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By measuring the serum IgM-level every fourth day after keratoplasty the primary immune response can be observed. The extent of the graft's reaction corresponds with the fluctuation of IgM. |
The paper describes a semi-closed ecological system consisting of a man and a photosynthetic autotrophic component. The conditions required to maintain the stability of the atmosphere in the system are described as applied to two alternating modes of the function of the autotrophic component. These conditions express equal quantities of oxygen and carbon dioxide consumed and produced by the components of the system during any time period the length of which is the duration of the cycle of the system. On this basis equations have been derived which help to identify the photosynthetic cultures that can be used as an autotrophic component in a closed man-sustaining life support system. |
The environmental control system using superoxides, sillicagels or synthetic ceolites is capable of purifying the atmosphere from microorganisms. The air conditioning system is another means for air purification from microorganisms. The possibility of microbial build-up and multiplication in the atmospheric condensate makes it necessary to assume that an air conditioning system may contribute to the transfer of conditionally pathogenic microorganisms in a space cabin. The reliability of a life support system may degrade due to an accumulation of microorganisms in its components. Further extensive studies are needed to clarify this problem. |
The experiments carried out on white male rats have shown no significant changes in the animals that may have resulted from their 30-day consumption of reclaimed water which contained up to 34 mg/l methanol and was produced by sorption purification of the atmospheric condensate during a prolonged manned experiment. |
The kinetics of the outgassing of volatile substances from polymers of different function and composition was studied with respect to their natural ageing. The outgassing rate was exponentially related to the time of the sample storage. Six to nine months after the polymer fabrication the outgassing rate decreased to a minimum. Possible nobilization of synthetic materials with the aid of diffusion stabilization and thermostatization was investigated. Practical recommendations on how to prevent contamination of the enclosed atmosphere with outgassed products of synthetic materials were developed. |
The paper describes a model of an experimental ecological system consisting of autotrophic and heterotrophic components and a nutrient medium. The system has a zero stationary state and needs a correction. The life time of the system and the level of the necessary correction have been determined for the experimental ecological system: lettuce - slugs - nutrient solution. Optimal conditions for the conjugation of trophic components of the system have been established. |
Control of mineral nutrition of higher plants is one of the problems involved in the development of life support systems. The experiments on carrots cultivated aeroponically have demonstrated that mineral nutrition of plants can be controlled by means of a correction solution applied in accordance with the protocols derived from experimental studies of increase in the plant dry biomass. |
In this paper the comparative evaluation of the results of the surgical and conservative treatment applied in patients with Perthes-Legg-Calvé disease is given. The results obtained with intertrochanteric femur osteotomy performed in 39 patients and those obtained in 66 patients with conservative treatment are reported. The results are evaluated from the point of view of the patients' age, the localization of the process and the stages of the disease. The surgical treatment brought about in 1/3 of the cases excellent-in 1/3 good - and in 1/3 unsatisfactory results. Int the group of patients who received conservative treatment 1/3 of the cases showed excellent - 1/5 of the cases good - and 3/5 of the cases unsatisfactory results. The advantage of the surgicat treatment is that the patients are not confined to bed for long time and they must nol use walking splint releasing the hip-joint. |
The literature data concerning the effect of the atmosphere composition on the photosynthetic productivity of an intensive microalgal culture were used to build a mathematical model of a semiclosed ecological system working in the light-dark alternating cycles. The type of the relationship between time cycles and composition of the stationary atmosphere of the ecological system has been established. The conditions of the existence and stability of the stationary atmosphere have been determined. |
The increasing number of respiratory insufficiency, as well as of pulmonary complications after burns and their role in the post-traumatic mortality are pointed out by the author. The pathophysiological processes responsible for the development of post-traumatic pulmonary complications are shortly resumed. In respect of the clinical picture, three groups are distinguished by the author. One case is reported in detail. In the development of post-traumatic respiratory insufficiency important role is attributed by the author to the syndromes of micro-embolism. This supposition is supported by the laboratory examination of 10 patients. Finally the problems of prevention and therapy are discussed and the importance of the iatrogenic damages is emphasized. |
The management of burns consists essentially of the surgical removal of the necrotic skin layers and the substitution of the skin defects. Secondary skin transplantation does not prevent completely the cicatrization and all complications of the burn. The management of burns is partially classed among the problems of the conservative therapy. Early excision excludes the danger of demarcation and infection, and immediate transplantation may prevent the destruction of the subcutaneous skin layers. This advantages are assured in the cases concomitant with partial necrosis by xenotransplantation. |
The surgeon assuming the task of reconstruction of burned face must be skilled in plastic surgery. Primary surgical treatment and reconstruction are inseparable, therefore it is desirable that the treatment is performed since the day of the injury to the completion of the reconstruction by the same surgeon. In the surgical management of the facial burns relative conservatism is advisable. The excision is to be performed after the recovery of the second-degree burned areas. The above-mentioned principles are documented by the author on the basis of a few cases. |
The number of the injuries and of the open fractures is steadily increasing. These latter are regularly due to traffic accidents. Characteristics of the open fractures are the extended lesion of the soft parts and the piece-like fractures. The treatmend depends on the patient's general state, the extension of the lesion of the soft parts, the contamination and the infection of the wound, as well as on the localization and the type of the fracture. In the case of proper indication the osteosynthesis yields satisfactory results, but it is not always to be performed and its use to exposed to dangers. The conservative treatment assures good results, if the lesion of the soft parts is minimal, the reduction of the dislocation is easily accoplished and the bone ends are to be held together. On the other hand, the method is unsuitable, if extended lesion of the soft parts occurs, as well as in the treatment of multifragmental fractures. In this group of the open fractures we must try to find other, new methods. |
On the basis of 7 years' material, the distribution of 73 foreign bodies - of non-metallic intensity - in the hand and the foot is discussed. The foreign bodies did not appear as new, fresh lesions, but they have been diagnosed after longer or shorter symptom-free state. In the case of fistulous process immediate removal has been performed, and in the case of closed cases - on the basis of the clinical picture - immediate removal - or removal after fixation for a few days was effective. In the author's opinion, fixation is - so long as acute symptoms are present - in all cases indispensable, - fixation is immediately followed by physicotherapy, in order to assure good functional results. |
In open fractures of the leg, in which because of any reason no primary stable osteosynthesis can be performed, threading with Kirschner wire is preferred by the authors. This method assures adaptation stability, with minimal osteosynthesis. Primary closure of the wound in the soft parts is striven by the authors, - if necessary, even by plastic surgery. If primary healing of the wound is obtained and also the other conditions are favourable, the treatment after 7-10 days is the same as after covered fractures: stable osteosynthesis is performed. On the other hand, if suppuration of the wound occurs, the opposing fixed fracutre bone ends assure favourable conditions for the successful surgical treatment of the fracture. A further advantage of the method is that it may be performed without special instruments and without greater surgical experience. The results obtained with this surgical treatment of open leg fractures in the 4 years' material of the Traumatological Department of the First Surgical Clinique of the University Medical School, Pécs, are discussed by the authors. |
In respect of iatrogenic infections the elderly patients are to be considered as endangered. Modern traumatology increases this danger in consequence of the foreign materials placed in the wounds. The role of the antibiotic and chemotherapeutic prophylaxis is of utmost importance. Regrettably, the resistance of the pyogenics, especially of the strains in the hospitals is increasing, - in consequence, besides the maximal sterility the further improvement of the surgical technique and of the after-treatment are the most important tasks. In the case of infection aimed antibiotic and chemotherapeutic, resp., treatment may be successful. |
The nowadays accepted principles of the treament of open leg fractures are discussed. The open character of the lesion multiplies the possibilities of complications. In the present paper the complications of the bone recovery are not dealt with, only the complications observed in the soft parts and the possibilities of their treatment are analysed by the authors. According to the severity of the soft parts complications free transplantation of semi-thick skin, pedicle flap plasty, double-end graft plasty, crossed flap grafting, as well as the primary and secondary variations of these methods are used by the authors. The satisfactory results obtained with these methods even in spite of the complications are pointed out by the authors. |
Open leg fractures observed in 81 patients are analysed by the authors. In case of conservative treatment alone and in the group, which has been treated with primary osteosynthesis satisfactory results have been observed by the authors. False joint and osteomyelitis happened only in the group, in which the patients obtained firstly conservative treatment and in the case of the failure of this treatment osteosynthesis has been carried out. In the authors' opinion the most frequent complications are due - besides the damage of the soft parts - to the repeated and sometimes erroneous interventions. |
The surgical treatment of a severe injury in the cubital region of a bus-driver, aged 47, is reported. Because of the extended contamination and the splintered fracture radical wound excision - involving also the chondral surfaces - has been performed and hereupon humero-radial arthrodesis was carried out. The skin defect has been successfully treated secondarily by insert of a flap. After uneventful recovery the patient could resume his work 6 months after the injury again. |
The injury due to burns embraces three, nearly concentric zones. The necrobiosis of the central and marginal zones is reversible and the pig-skin - assuring biological ligature - plays important role in turning for better of the process. The preparation and use of Xenograft - applied in the author's department - is discussed. |
Mosquito-borne arboviruses are prevalent throughout subarctic regions of Canada and Alaska, principally in the boreal forest extending between latitudes 53 and 66 degrees N, but they have been identified in tundra regions as far north as 70 degrees N. All mosquito-borne agents have been bunyaviruses, comprising principally the snowshoe hare subtype of California encephalitis (CE) virus, but also Northway virus. Mosquito vectors comprise several Aedes species and Culiseta inornata, all of which have supported replication of CE virus following incubation at 13 degrees C or lower temperatures. Isolation of virus from wild-caught larvae points towards transovarial transfer. Principal vertebrate reservoirs of infection are mammals, especially snowshoe hares (Lepus americanus) and ground squirrels (Citellus undulatus). Where the boreal forest merges into prairie grassland around 53 degrees N, Culex tarsalis mosquitoes become prevalent, and an alphavirus, western equine encephalomyelitis, is detected more frequently than CE virus. |
Mosquito longevity and blood-feeding behaviour are very important but neglected factors in the dynamics of arbovirus infections as changes in them affect transmission rates exponentially. Some mosquito species feed on a narrow range of vertebrates, some on a wide range, both influenced by host-availability and other environmental and behavioural factors. Only those which feed on maintenance hosts contribute to maintenance of the infection. Some species change their feeding pattern with season. The frequency of blood-feeding depends inter alia on environmental temperature. Longevity is perhaps most important: the majority of mosquitoes infected probably do not survive long enough to become infective; it is influenced by relative humidity, temperature and predation. Longevity, feeding frequency and the extrinsic incubation period are all temperature dependent and are therefore important rate determinants in seasonal epizootics or epidemics. Equally, their relative stability in the tropics contributes to the equilibrium of an enzootic or endemic. |
The nucleocapsid of the Semliki Forest virus is composed of 34% RNA and 66% protein, or one RNA and about 240 capsid protein molecules. The particle is spherical, with a diameter of 38--39 nm. If the nucleocapsid is exposed to slightly acid pH (6.4--5.6) it undergoes a structural change and is contracted to a 32 nm state. A similar contraction can be effected by RNase treatment, in this case, however, in connection with a loss of RNA. Treatment of the nucleocapsid with 0.2 mM SDS results in dissociation of capsid protein from RNA, an effect which suggests strong RNA-protein interaction. At 0.05 mM SDS the protein remains associated with the RNA, but the S-value is reduced from 150 S to 100 S. Electron micrographs of the 100 S ribonucleoprotein showed irregular and strand-like structures. |
The present data show that SPN have a striking influence on thymus dependent T cells. The enhancing effect of gvh reactions on antibody formation against thymus dependent antigens give a good explanation for the antitumor effects of this substance. |
The morphology and function of the urethrovesical junction are described to give some understanding of the pathogenesis and therapy of female stress incontinence. Conservative procedures can only be helpful in stage-1 stress incontinence, whereas in stage 2 surgical treatment provides excellent results. |
The activity of pyruvate dehydrogenase from freshly isolated mitochondria was shown to be dependent upon the nutritional and metabolic state of the animal prior to sacrifice, such that mitochondria from the livers of 48 hr starved, diabetic, or high fat fed rats had lower enzyme activity than normal, chow fed rats. The activity of pyruvate dehydrogenase and the rate of lipogenesis were shown to correlate to a certain extent when a reconstituted, cell free system consisting of 105,000 x g supernatant of rat liver and isolated mitochondria was used. This system was employed so that the role of the mitochondrion and pyruvate dehydrogenase in lipogenesis could be investigated. Dichloroacetate increased the activity of pyruvate dehydrogenase and increased the rate of lipogenesis, suggesting that the activity of pyruvate dehydrogenase is an important factor in determining the rate of lipogenesis in the reconstituted system. It was observed, however, that dichloroacetate was more effective in stimulating the activity of pyruvate dehydrogenase than the rate of lipogenesis when mitochondria from starved animals were used to reconstitute lipogenesis. Furthermore, the cytoplasmic adenosine triphosphate/adenosine diphosphate ratios and phosphorylation potentials (ATP/ADP x Pi) maintained in the reconstituted system by mitochondria isolated from starved animals were found to be significantly lower than those maintained by mitochondria isolated from chow fed animals. It is proposed that the lower "energy pressure" maintained in the reconstituted system by mitochondria isolated from starved animals severely limits lipogenesis at the ATP requiring steps of the process. |
Testicular tissue was shown to contain the full complement of enzymes required for de novo synthesis of fatty acids. The enzymes capable of snythesizing palmitic acid from citrate, acetate, or acetyl CoA were found to be present in the soluble (cytoplasmic) fraction. These included fatty acid synthetase, acetyl CoA carboxylase, citrate-cleavage enzyme, malic enzyme, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase. Optimal conditions for assaying activities of fatty acid synthetase and acetyl CoA carboxylase in the soluble fraction from rat testes were established, and the activities of these two enzymes were determined to be 0.54 +/- 0.1 and 0.030 +/- 0.002 (nmoles of substrate incorporated into fatty acid per min per mg of soluble fraction protein), respectively. The activities of citrate-cleavage enzyme, malic enzyme, and the glucose-6-phosphate dehydrogenase/6-phosphogluconate dehydrogenase pair were also measured. The activities were 6.0 +/- 0.7, 34.9 +/- 4.2, and 29.9 +/- 9.3 nmoles/min/mg, respectively. |
An in vitro system for acetate incorporation into fatty acids by the mitochondrial and the cytosol fractions of rat testis is described. The rate of incorporation of acetate into fatty acids was twice as fast with the mitochondrial as with the cytosol fraction; both systems were stimulated in the presence of adenosine triphosphate, reduced nicotinamide adenine dinucleotide phosphate, coenzyme A, and MgC1(2). The optimum pH was between 7.0-7.5 for the mitochondrial fraction and between 6.5-8.0 for the cytosol fraction. Radio gas chromatography showed that palmitic acid was the most highly labeled acid, followed by stearic acid, in the mitochondrial fraction in accord with the pathway of de novo fatty acid synthesis. Some of the labeled acetate was also incorporated into the 16:1 and 18:1 fatty acids of this fraction. Distribution of radioactivity among the mitochondrial lipid classes was highest in the phospholipids and monoglycerides, followed by diglycerides and cholesterol; little radioactivity was present in the triglyceride fraction. These observations are in accord with studies of the incorporation of labeled metabolites into testicular lipids following intratesticular injection and indicate the validity of the in vitro system for studies of specific reactions occurring in vivo. |
Cell free preparations of avocado mesocarp and spinach leaf tissue rapidly convert lauryl CoA to DL-3-hydroxyl lauric acid as well as 2-, and 3-dodecanoic acids. The conversion does not occur under anaerobic conditions unless a suitable redox carrier such as ferredoxin is present. H2 18O is incorporated into the 3-hydroxyl function, but O2(18) is not. The characteristics of this system are presented and a possible function of this system is proposed. |
Transplantable mammary adenocarcinomas and livers of C3H mice fed a stock diet or a linoleate rich diet (15% corn oil) contain similar amounts of oleate (ca 3 mg/gm tissue). On feeding either a high carbohydrate, fat free or a high carbohydrate, saturated fat-containing (15% hydrogenated coconut or cottonseed oil) diet for 6 weeks, oleate levels increased 2-fold in tumor and 5-fold in liver. The specific activity of stearoyl-CoA desaturase in liver microsomes was similar to that in the corresponding fractions of mammary glands of lactating mice. In liver, this activity was enhanced 2- to 3-fold by feeding a high carbohydrate, fat free or a high carbohydrate, saturated fat diet. The desaturase activity in mammary tumor microsomes, while only 10% of that in hepatic microsomes, remained unaltered regardless of the type of diet fed. These observations suggest that (a) a major portion of the oleate in the mammary tumor is not produced within the tissue, (b) dietary adaptation is not a general characteristic of stearoyl-CoA desaturase in neoplastic tissues, and (c) enhanced desaturase activity in liver is directly related to the absence of linoleate or oleate, or to a large decrease in oleate in the diet. |
During the 1973 and 1974 state high school wrestling championships, urine samples were obtained from wrestlers prior to the weigh-in, immediately before they wrestled, and immediately after the subjects had completed their match. Specific gravity, osmolarity, pH, sodium and potassium determinations, as well as qualitative tests for protein and ketones, indicated that the wrestlers were in a dehydrated state at the time of weigh-in. After the five hour interim between the weigh-in and the first match, all but the pH measure remained essentially unchanged. This absence of significant changes in the urinary profile suggests that the wrestlers were unable to rehydrate during the five hour time period between the weigh-in and the first match and that they were competing in a dehydrated state. Urine samples collected after competition were significantly lower in specific gravity, osmolarity and potassium concentration than samples obtained before the match. The urinary potassium levels were of interest because at the three conditions (weigh-in, before the first match, after competition) they were 73-182% higher than values reported for high school students who were nonwrestlers. |
The development of generalized necrotizing vasculitis in association with hepatitis B antigenemia is the first example in man of a chronic rheumatic disease presumably caused by a viral infection. This report reviews the experience in nine biopsy-proven cases of hepatitis B-associated necrotizing vasculitis followed for up to six years. The natural history of the disease is emphasized and the manifestations of patients with vasculitis who carry hepatitis B antigen are compared with those of vasculitis patients who are antigen negative. |
An association between viral hepatitis and two rheumatic disease syndromes has been observed. Twenty-nine patients manifested a transient polyarthritis, sometimes associated with a rash (Group I). Ten patients were seen with a multisystem disease (Group II). Histologic evidence of arteritis or glomerulonephritis was present in seven of ten patients with multisystem disease. Liver tissue from 18 patients showed morphologic evidence of hepatitis with viral features in 9 of 10 patients in Group I and in 6 of 8 patients in Group II. Hepatitis B surface antigen (HBsAg) and/or antibody to HBsAg were detected in sera of all 39 patients. Abnormal liver functions were present in 36. Twelve Group I patients and 2 Group II patients became jaundiced. Rheumatoid factor was present in sera of seven patients in each group. The third component of complement (C3) was depressed in 13 patients in Group I and 7 patients in Group II. The fourth component of complement (C4) was decreased in 8 of 21 Group I and 3 of 7 Group II patients. Synovial fluid C3 was decreased in 2 of 11 Group I and 1 of 4 Group II patient's fluids. Articular inflammation in patients with transient polyarthritis responded in three to seven days to aspirin, acetominophen and/or bedrest alone and rashes disappeared spontaneously. Patients with multisystem disease generally had a prolonged illness and responded somewhat unpredictably to prednisone or a combination of prednisone and cyclophosphamide. |
In healthy male subjects aldosterone excretion and plasma renin activity were reduced by a 4-6 hr head-out immersion in thermoindifferent water baths (35.5 +/- 0.1 degrees C). The red cell 2,3-diphosphoglycerate (DPG) concentration before and throughout immersion period was positively correlated both with aldosterone excretion in 2 hr pooled urine (r = +0.69; 2 p less than 0.001) and with renin activity (r = + 0.54; 2p less than 0.001) despite a concomitant increase of cubital venous pH and inorganic phosphate concentration. These findings furnish evidence for a regulatory role of aldosterone in DPG metabolism, possibily by a direct influence on red cell glycolysis. |
Rhodopseudomonas palustris, Rh. viridis, Rh. acidophila, and Rhodomicrobium vanniellii grow on media containing ethanol, n-propanol, and n-butanol. The highest amount of lower alcohols is utilized by the strains of Rh. palustris. Only Rh. acidophila accumulates methanol. Alcohol dehydrogenase of Rh. palustris, Rh. viridis, and Rhodospirillum rubrum requires for its activity NAD, that of Rhodomicrobium vanniellii--NADP, and the enzyme of Rh. acidophila is active in the presence of phenazine metasulphate (PMS) and ammonium ions. Aldehyde dehydrogenase from two strains of Rh. palustris also requires NAD; the Nakamura strain is active in the presence of PMS. Aldehyde dehydrogenase of Rh. acidophila is active in the presence of PMS and ammonium ions. Different bacterial species vary in the substrate specificity of their alcohol dehydrogenases. |
Mycobacterium lacticolum 121 grows and synthesizes exopolysaccharide at the initial values of pH of the medium from 5.0 to 11.5. The accumulation of biomass is maximal (10 to 12 gram/litre) at pH 6.0 to 11.5; the rate of growth is highest at pH 8.0 to 11.5. The largest amount of exopolysaccharide (2.0 to 2.4 gram/litre) is produced in the medium at pH 8.0 to 11.0; the rate of its production is highest at pH 9.0 to 11.0. The growth of Mycobacterium lacticolum 121 and the biosynthesis of polysaccharide are optimal at pH 8.0 to 8.2. Changes in acidity of the medium have no effect on the qualitative composition, structure, and molecular weight of the polysaccharide. |
The growth of Pseudomonas methanolica was inhibited by unfavourable values of pH in the conditions of chemostat; the rate of the substrate assimilation was higher, and anabolic and catabolic reactions were decoupled. Hydrogen ions inhibited the activity of enzymes of the Krebs cycle, hydroxyl ions inhibited the activity of methanol dehydrogenase. Changes in pH are presumed to involve the energy apparatus of the cell membrane. |
Report dealing with the clinical and pathoanatomical course as well as the autopsy findings in a 54 year old female suffering from panarteritis nodosa. Onset of the illness with polyneuritis and arthralgia. One year later diagnosis of panarteritis nodosa verified by muscle biopsy. Deterioration of the disease leading to the development of peripheral gangrene could not be prevented in spite of intensive therapy with steroids, immune suppressive agents, digitalis and antihypertensive drugs. Death 4 years later by myocardial infarction. Autopsy revealed generalized healed panarteritis nodosa with scarring and obliteration of vessels. A short description of the symptoms of the disease is given and the efficacy of the therapy with steroids and immune suppressive drugs is discussed from the clinical as well as the pathoanatomical point of view. Immunopathologic mechanisms are considered to be the responsible factors for pathogenesis. |
The lysis of Actinomyces rimosus producing oxytetracycline during its mass growth can be caused by two factors which were separated by differential centrifugation. The first factor is phage particles of a temperate phage produced by the culture; they are incapable of growth but may induce the lysis. The phage particles treated with low pH and a temperature of 70 degrees C lose the lytic activity. The second factor is a lytic enzyme produced under the control of the temperate phage during its induction; it seems to consist of at least two enzymes, a lytic enzyme and a proteolytic enzyme. |
Pulmonary artery and pulmonary wedge pressures were measured at rest and during exercise in 25 young patients with moderate to severe scoliosis. Simultaneous determinations of arterial blood gases and pH were performed. The results of the vascular pressure measurements were compared with those obtained in 15 healthy young subjects. In all patients the pulmonary artery and pulmonary wedge pressure were normal at rest. During mild ergometer exercise, however, an abnormal rise in pulmonary artery pressure occurred in 9 patients. Moreover, an increased diastolic pressure gradient across the pulmonary vascular bed was found in some scoliotic patients indicating an elevated pulmonary vascular resistance. It is supposed that this haemodynamic abnormality is primarily due to a restriction of the pulmonary vascular bed. Relationships between pulmonary artery pressure and arterial oxygen tension and blood pH, respectively, could be found. The possible significance of these results is discussed. |
We studied the relative importance of hyperkalemia and mineralocorticoid deficiency in the metabolic acidosis of a patient with proved isolated hyporeninemic hypoaldosteronism and moderate kidney failure. The hyperkalemia and acidosis were severe in relation to the slight azotemia. Despite the systemic acidosis and urinary pH of 4.9, urinary ammonium excretion was distinctly blunted. Correction of the hyperkalemia by potassium-sodium exchange resin alone resolved the acidosis and restored the previously diminished urinary ammonium excretion to normal. Administration of mineralocorticoids only partially corrected the hyperkalemia and the acidosis. Hyperkalemia by itself, rather than hypoaldosteronism per se, caused the acidosis in this patient. Hyperkalemia apparently suppresses urinary ammonium excretion and thus interferes with urinary acidification. |
Penicillium corylophilium Dieckx was isolated from sludge collected at the interface of an aqueous, copper-bearing leachate and an organic, kerosene based, ion exchange solvent. The organism assimilated kerosene and various straight chain and cyclic hydrocarbons including dodecane, hexadecane, octadecane, toluene, benzene, and cyclohexane. Assimilation of kerosene and hexadecane was optimal at pH 2 and was stimulated by yeast extract. |
Chitinolytic microorganisms isolated from forest soil and from healthy gypsy moth larvae (Porthetria dispar (L.) were screened for their ability to lyse Trichophyton rubrum mycelia. A few of these isolates were mycolytic on both autoclaved and on actively growing, intact, T. rubrum mycelia. Supernatants from these isolates, utilizing live T. rubrum as the sole carbon source, showed the same mycolytic ability. Assays of the supernatants for enzymatic activity revealed exocellular, stable enzymes that releases reducing substances including N-acetylglucosamine from the mycelia. |
A model catalyst is described which has properties in common with carbonic anhydrase. The model demonstrates the availability of a mechanism, previously only hypothetical, for the action of the enzyme. It also shows, however, that this mechanism alone is not adequate to produce the high activity of the enzyme. |
Studies were made of the mechanisms regulating the quantity and catalytic efficiency of hepatic acetyl coenzyme A carboxylase, which plays a critical role in the control of fatty acid biosynthesis. The microsomal enzyme system responsible for the formation of phosphatidic acid, the initial step in glycerolipid biosynthesis, was resolved into two component enzymes. The acyl-donor specificities of these and other acyltransferases account for the asymmetric fatty acid distribution in naturally occurring glycerolipids. |
Strains of transmissible gastroenteritis (TGE) virus possessing different pathogenicity were examined for stability to digestive enzymes and acid, and growth at various temperatures. In growth experiments, virus titer obtained at 37 degrees C were about equal between attenuated and virulent strains, but titers attained by the attenuated strain were higher at 30 degrees C. The attenuated virus multiplied at 28 degrees C, but the virulent virus did not at this temperature. The virulent virus was significantly stable to trypsin and pepsin, but the attenuated virus was inactivated rapidly by these proteolytic enzymes. No significant differences were observed in stability to acid between the attenuated and virulent strains. At different pH, both lost their infectivity more rapidly at 37 degrees C than at 22 degrees C. |
The established hamster lung cell line, HmLu-1 cells could grow in a suspended state. The initial cell count, 40 X 10(4)/ml, increased to 200 X 10(4)/ml on the 4th day of culture. The suspension culture of HmLu-1 cells was proved satisfactory for propagation of Ibaraki virus. The viral titer reached a maximum of 10(6.75) TCID50/0.1 ml. The input multiplicity ranging from 0.003 to 3.0 exerted no influence on the final yield of the virus. The optimal pH value of initial culture ranged from 6.8 to 7.6. In comparison of virus yield per cell among the suspension culture and two methods of monolayer culture in stationary and rolling condition, there was no noticeable difference in it among the three methods. The cell population per unit volume was the largest and, therefore, virus titer in the culture fluid the highest in the suspension culture of the three methods. |
The influence of some drugs on the effect of morphine on the threshold pressure required to elicit peristalsis in the guinea pig ileum in situ was studied, in order to test the hypothesis that this effect of morphine is mediated by catecholamine release. Tachyphylaxis to this effect of morphine was confirmed. Pretreatemnt with two 8 mg/kg doses of reserpine, 24 and 48 hrs before the experiment, significantly reduced the effect of morphine on the pressure threshold. The i.v. administration of 10 mg/kg dl-Dopa re-established the effect of morphine in reserpinized animals to the level of the untreated controls. Pretreatment with guanethidine (15 mg/kg) decreased and even prevented this effect of morphine. Phentolamine pretreatment (10 mg/kg) also significantly inhibited the effect of morphine. Neither DCI nor propranolol influenced this morphine effect. Pretreatment with reserpine, guanethidine or phentolamine reduced the basic pressure threshold needed to elicit peristalsis. The possibility that the decrease of local circulation induced by hypotenison would reduce the local concentration of morphine was rejected because the same doses of guanethidine or phentolamine did not modify the effect of hexamethonium given i.v. in this preparation. All these results support the idea that the effect of morphine on intestinal peristalsis is mediated by a catecholamine acting on alpha-receptors, e.g. norepinephrine. |
In perifused isolated pancreatic islets alpha-ketoisocaproic acid (KIC) or alpha-ketocaproic acid (KC) induced a high insulin secretion rate and a steep increase of the fluorescence of reduced pyridine pyridine nucleotides [NAD(P)H] which fell again to almost prestimulatory levels 6 min after medium change. Insulin release in response to alpha-ketooctanoic (KO) acid started slowly and was accompanied by a decrease of the NAD(P)H-fluorescence trace. Beta-phenylpyruvate which is known to initiate insulin release also caused a fluorescence decrease. Alpha-keto-isovaleric (KIV) acid or pyruvate had no significant effects upon insulin secretion or NAD(P)H-fluorescence. In contrast to l-leucine, l-norleucine or l-valine did not enhance insulin release or fluorescence of NAD(P)H. KIV, alpha-keto-beta-methylvaleric acid (KMV), KIC and KC raised the production their corresponding amino acids by islet cells. From these results it is concluded that alpha-ketomonocarboxylic acids as such trigger insulin release by acting upon receptor sites which differ from those occupied by amino acids. |
The nerve growth factor (NGF) subunit of 7S NGF was isolated by chromatography at high pH on QAE-Sephadex. It has the same specific NGF activity as betaNGF isolated at acid pH, showing that this activity is an intrinsic property of the subunit and is independent of the pathway of dissociation. Continued exposure of the NGF subunit to high pH resulted in an increase in the amount of the minor species beta2NGF and the formation of a new species, beta3NGF, of even lower isoelectric point. These two species and the original major species of the preparation, beta1, were isolated by isoelectric focusing. All three species had the same specific NGF activity, but differed in their ability to reform 7S NGF. The beta2 species was one-fifth as competent as beta1, while beta3 was unable to regenerate 7S NGF. Addition of alpha- and gamma-subunits to beta1NGF decreased the amount of NGF protein required to produce one Biological Unit of activity in the bioassay, but had no effect when added to beta3NGF. The interactions between the subunits in 7S NGF therefore determine, in part, the specific activity of the NGF subunit. |
The affinity of concanavalin A for neutral and acidic glycopeptides derived from rat brain glycoproteins was investigated by studying the inhibition of a concanavalin A-glycogen precipitation system. The neutral, mannose-rich glycopeptides obtained by column electrophoresis of the dialyzable glycopeptides that had been solubilized by proteolytic treatment of defatted brain tissue were powerful inhibitors, with an inhibitory activity 20 to 26 times that of the standard inhibitor, methyl-alpha-D-mannoside. The acidic sialoglycopeptides had activities one to nine times that of the mannoside. Therefore, both acid and neutral glycopeptides were capable of interacting with concanavalin A. The especially strong affinity of the neutral mannose-rich glycopeptides, however, enabled their retention on concanavalin A-Sepharose and subsequent elution with methyl-alpha-D-mannoside. This provided the means of separation of the acidic sialoglycopeptides from the neutral, mannose-rich glycopeptides by affinity chromatography. Glycopeptides that contain N-acetylgalactosamine are not retained by concanavalin A-Sepharose. |
The major protein in beta nerve growth factor preparations, beta1NGF, is a dimer in which both peptide chains have COOH-terminal arginine residues. Digestion of beta1NGF with carboxypeptidase B produced a dimer, beta3NGF, in which both chains lack these terminal arginine residues. Exposure of mixtures of beta1 and beta3NGF dimers to 8 M urea to produce monomers, followed by removal of urea to allow recombination, resulted in the formation of the hybrid beta2NGF, comprising one arginine-containing and one arginine-less chain, as well as the parent dimers. The amount of the three dimers formed was close to that expected from random association of monomers. Hybrid beta2NGF was also formed from mixtures of beta1 and beta3NGF where incubated at pH 2.6 to 4.5. The formation of beta2NGF has a half-time of 6 h at pH 4.0 and 4 degrees C. Its rate of formation decreased above pH 4.5, becoming minimal between pH 9.5 and pH 10.5, and increased with increasing temperature. The amount of beta2NGF formed was determined by the lowest pH to which the parent mixture was exposed, irrespective of its prior history. These data suggest that the hybrid is formed by the same mechanism in the absence and presence of the urea step. An approximate value for Kd, the equilibrium dissociation constant of the dimer equilibrium monomer equilibrium was derived. Its value was 3 - 10(-10) M at pH 4.0 and 4 degrees C. The alpha-subunit of 7S NGF decreased the rate of formation of beta2NGF not only at pHs where an alphabeta complex is stable, but also at an acid pH where no complex formation is observed by sedimentation analysis, suggesting that the present methodology offers a more sensitive probe of subunit interactions. In contrast, the gamma subunit and a number of indifferent proteins had little or no effect on the appearance of beta2NGF at the pHs studied. |
Rats subjected to pinealectomy or to pinealectomy plus bilateral superior cervical ganglionectomy exhibited depressed serotonin uptake by hypothalamic synaptosomes; norepinephrine, dopamine or glutamate uptake was not affected by any of the surgical procedures. Treatment with melatonin resulted in inhibition of hypothalamic serotonin accumulation but it did not modify the uptake of norepinephrine, dopamine or glutamate. These data suggest a relationship between the pineal gland and the serotoninergic nerve endings of the hypothalamus. |
The antihypertensive activity of timolol (Blocadren, FROSST-MSD), a new beta blocking agent, was assessed in a single blind crossover placebo-controlled study in 14 patients with essential hypertension. Ten patients completed the trial. The average standing pressure during the placebos periods was 168/109mmHg and during the periods on treatment with timolol the average standing pressure was 139/92mmHg. All 10 patients showed some hypotensive response. The average daily dosage was 21 mg with a range of 15-30 mg. Four patients achieved optimal levels of blood pressure by the end of one week's therapy with the maximum time required being four weeks. Timolol appears to be an effective antihypertensive agent. Side effects were insignificant. |
The effects of ritodrine hydrochloride were evaluated in 25 toxemic patients in active labor utilizing continuous electronic monitoring of fetal and maternal cardiovascular systems and uterine activity. Fetal scalp blood and free flowing maternal antecubital venous blood was obtained for pH, Po2, Pco2, base deficit and blood glucose determinations prior to and immediately following the study period. The initial ritodrine dose was 50 mug/min for 15 minutes. The dose was increased by 50 mug/min each 15 minutes until there was a clinically apparent reduction in uterine activity. Once this was accomplished, the infusion was maintained for 30 minutes. There was a consistent increase in the maternal heart rate (MHR) and a significant rise in fetal heart rate (FHR) late in the infusion and in the postinfusion period. There was a widening of the maternal pulse pressure mainly due to a reduction in diastolic pressure with little change in the mean blood pressure. Maternal and fetal pH decreased and base deficit increased during the study although the PO2 and PCO2 remained unchanged. Maternal and fetal blood glucose rose significantly following ritodrine infusion. |
Ovarian hyperstimulation was produced by human menopausal gonadotropin and chorionic gonadotropin in rabbits. A more rapid regression of the hyperstimualted ovaries was observed in an antihistamine-treated group than in a control group. The difference in regression was found to be statistically significant. The possibility of treating the ovarian hyperstimulation syndrome by antihistamine is cited. |
Jovian plants have enviroments apparently suitable for the evolution of life, but nevertheless, present severe challenges to organisms. One such challenge arises from the presence of ammonia. Ammonia is an efficient biocide, its effect being dependent on pH as well as on concentration. The effects of pH and ammonia concentration were studied separately, where possible, on a variety of organisms, including some isolated from natural enviornments of high pH and/or ammonia concentration. Escherichia coli and Bacillus subtilis are both extremely sensitive to ammonia. An aerobic organism (growth up to pH 11.4) from an alkaline spring is more resistant, but exhibits a toxic response to ammonia at a pH much lower than its maximum for growth. The greatest ammonia resistance has been found in an unidentified organism growing at near neutral pH. Even in this case, however, survival at ammonia concentrations reasonably expected on the Jovian planets is measured in hours. This is, nevertheless, two to three orders of magnitude longer than for E. coli. Our data support the tentative conclusion that contamination of the Jovian planets with terrestrial organisms that can grow is unlikely. However, the range of toxic response noted, coupled with the observation that terrestrial life has not been exposed to high ammonia concentrations for millions of years, suggests that adaptation to greater ammonia tolerance may be possible. |
Gamma-Glutamyltranspeptidase (GGTP) activity was studied in livers of rats submitted to an end-to-side portacaval shunt (PCS) and in developing animals. To correlate the evolution of the enzymatic activity measured in vitro, histochemical techniques were used to localize enzyme activity in liver tissue. The GGTP activity in the adult rats was low and amounted to 2.0 +/- 0.1 mumol/min/g. During fetal development the enzyme activity rose beginning on the 15th gestational day from 630 +/- 97 to 1,058 +/- 20 on the first postnatal day. Then the values declined and reached nearly adult values from the 10th postnatal day. After PCS the GGTP activity exhibited a three- to sixfold increase (130 +/- 69 to 371 +/- 131) as compared with unoperated adult controls (53 +/- 13). the highest levels corresponded to those observed between the 3rd and 5th postnatal day in the developing rats. The histochemistry of GTTP in the fetal and newborn liver showed a regular distribution of the enzyme as a fine deposit in the hepatocytes throughout the whole tissue. Ten days after birth the activity was low, at the same level as in the adult rat. In the period after PCS hepatocytes began to show signs of enzymatic activity at the periphery of the hepatic lobules, which subsequently spread through the whole lobules. The increase of GGTP activity after PCS equaled the activity found in fetal animals. That correlated well in both groups with the reappearance of histologically demonstrable enzyme activity in hepatocytes. |
Modified stereotaxic techniques were applied to fetal lambs during the latter third of gestation. Electrical stimulation in the region of the hypothalamus in 10 acute experiments was associated with three patterns of arterial blood pressure and heart rate changes: a pressor-tachycardia response; a pure tachycardia response (abolished by propranolol); and a pure bradycardia response (abolished by atropine). The pressor-tachycardia response was examined in detail in 13 chronic preparations (115-135 days of gestation at operation). The systolic arterial blood pressure increase was never greater than 35 mm Hg and was probably blunted by the large noninnervated placental circulation. This pressure increase was abolished by phentolamine and was thus mediated by stimulation of alpha-adrenergic receptors. The initial tachycardia was prevented by propranolol and was due to beta-adrenergic stimulation. The tachycardia was followed in a few seconds by a bradycardia, abolished by atropine and possibly a vagal baroreflex. The pressor-tachycardia response was accentuated in two lambs who were delivered spontaneously and were studied after birth. These studies indicate that a suprabulbar neural framework exists in the fetal lamb for influencing the cardiovascular system from as early as 90 days of gestation. |
Mucocutaneous lymph node syndrome (MCLS) is a newly recognized disease characterized by fever persisting for more than 5 days, an erythematous skin eruption, conjunctival congestion, dry red fissured lips, reddened tongue, palms, and soles, nonpurulent lymphadenopathy, and sometines diarrhea, arthralgia, and aseptic meningitis. Additional features may include carditis, pericarditis, aneurysmal dilation and thrombosis of coronary arteries, and sudden death. There is a striking similarity of fatal cases to infantile polyarteritis nodosa, a disease recently reported to be associated with elevated levels of serium IgE. Indeed, it is likely that MCLS represents a disease which can progress to polyarteritis nodosa in infants and young children. The paired acute and convalescent serum IgE levels of 20 subjects with acute nonfatal MCLS were studied along with 20 near-age unaffected controls from the same communities in Japan. The results indicate that most if not all subjects with MCLS in the study had an elevation of total serum IgE during the acute phase of the disease (geometric mean 157 IU/ml compared with the control value of 38 IU/ml, P = 0.005). The level appeared to reach a peak 1-2 weeks after onset and declined over the ensuing 1-2 months. |
Lung slices from term fetal rats were incubated in vitro at various pH values and the rates of the two de novo pathways for lecithin biosynthesis were determined by measuring the conversion of either 14C-choline (pathway 1) or 14C-methionine (pathway 2) to the phospholipid. It was observed that the choline pathway, but not phosphatidylethanolamine methylation, is pH-sensitive with maximum rates occurring at pH levels between 7.3 and 7.5; significantly less activity was found at pH levels between 7.0 and 7.2 and at pH levels between 7.6 and 8.0. Adjustment of the pH from 7.0 to 7.4 in vitro simulating the clinical correction of acidosis by alkali infusion was found to increase the conversion of choline to lecithin to a rate approximating that observed at pH 7.4. Since lecithins are the principal phospholipid components of pulmonary surfactant, and since pathway 1 is predominantly responsible for lung lecithin synthesis, the demonstration of impaired production with reduced pH offers a biochemical explanation for the pathophysiological effects of acidosis in the respiratory distress syndrome. A comparison of pH effects on choline pathway rate with the pH profiles of pathway enzymes suggests that these effects are mediated by the catalysts of lecithin synthesis. |
The bicarbonate concentration in rat parotid saliva increases with increasing flow rates and approximates plasma values at highest salivation. At lowest flow rates the bicarbonate concentration in the secretory fluid markedly exceeds the plasma levels. Intravenous administration of acetazolamide has no influence on the bicarbonate excretion of the parotid gland. Following retrograde application of acetazolamide into the gland duct the concentrations of both bicarbonate and sodium are elevated. The potassium concentrations in final saliva exceed 70 mEq/l at flow rates below 5 mul/min g gland weight. With increasing flow rates a precipitous decrease in potassium concentration below 10 mEq/l occurs. With further increase in flow rate the potassium concentration remains unchanged. The sodium concentrations increased with augmented salivation rate. At lowest flow rates the sodium concentrations showed an increase of modest degree. Our findings can best be explained by the existence of two independent ductular mechanism: a) bicarbonate reabsorption probably in the striated ducts of the parotid gland; b) secretion of potassium with concomitand secretion of bicarbonate in the main excretory duct. |
An ATPase stimulated by HCO - ions and other oxybases and inhibited by SCN- has been found in main excretory duct of rat submaxillary gland, a tissue, capable of actively secreting HCO - 3 ions. No such ATPase was found in the rabbit duct, which normally does not secrete HCO - 3. The HCO - 3 ATPase was localized in the plasma membrane fraction of the homogenate, as evidenced by the marker 5'-nucleotidase. The activities of the HCO - 3 ATPase increased in metabolic alkalosis and decreased in metabolic acidosis in parallel to secretion of HCO - 3 and K+ ions by the duct epithelium. These findings provide further evidence that the membrane-bound HCO - 3 ATPase is involved in active H+/HCO - 3 transport. |
The ventilatory responses, blood gases and acid-base status to intravenous injections of KCN and doxapram hydrochloride were studied in anesthetized dogs during normothermia and at two levels of hypothermia. In the normothermic animal, KCN evoked significant elevations of minute and alveolar ventilations. For the mildly hypothermic (32-33 degrees C) dog, minute and alveolar ventilations were proportionally greater than for normothermia. Bolus infusions of KCN to deeply hypothermic dogs (28-29 degrees C) elicited larger and nearly similar increases of minute and alveolar ventilations as compared, respectively, with normothermia and mild hypothermia. Compared to their controls, injections of doxapram during normothermia, mild and deep hypothermia augmented VE 43.3%, 63.6% and 31.5%, respectively. With doxapram there was a feeble increase in alveolar ventilation. These results demonstrate that the peripheral (arterial) chemoreceptors preserve the capacity to respond to stimuli given acutely while lowering core temperature and in some circumstances this capacity is even enhanced as compared to normothermia. |
The ventilatory responses, blood gases and acid-base status to intravenous injections of KCN and doxapram hydrochloride were studied in anesthetized dogs during normothermia and thermally induced panting. In the normothermic animal, KCN evoked elevation of VE (154.7%), VT (70.1%), f (48.3%, PaO2 (12.1%) and pH (0.098 units), while PaCO2 diminished by 9.7 mm Hg. During panting, KCN infusions resulted in increases of VE (24.5%), VT (46.6%), PaO2 (3.9%) and pH (0.034 units), while f decreased (10.1%). Bolus injections of doxapram during normothermia increased VE (32.6%), VT (18.8%) and f (17.1%). During panting VE, VT and f increased by 18.0%, 18.2% and 1.5%, respectively. These results demonstrate that the peripheral (arterial) chemoreceptors preserve the capacity to react to acute chemical stimuli in animals in which the thermal stimuli override the normal chemical control of respiration in order to control body temperature, and that this reaction contributes to the integrated respiratory drive. |
Alpha-Adrenolytics (ABA)-phenoxybenzamine, phentolamine and aceperone-increase 5-hydroxyindoleacetic (5-HIAA) acid content in rat's brain. At the same time, these compounds either increase or do not affect 5-hydroxytryptamine (5-HT) level. Moreover, they potentiate L-dopa and reserpine-induced increase in 5-HIAA level and antagonized clonidine-induced decrease in 5-HIAA content. The experiments with probenecid indicate that the observed increase in 5-HIAA does not result from the deficient elimination of the metabolite from brain. The increase in 5-HT turnover in brain, due to ABA, is suggested. |
Diabetic ketoacidosis is an acute medical emergency that requires immediate diagnosis and treatment. Diagnosis may be established rapidly by measurement of urinary glucose and ketones, arterial blood pH and blood gases, and serum ketones. Rapid infusion of large volumes of fluids and electrolytes, together with continuous infusion of low doses of insulin, provides effective restoration of fluid and electrolyte balance and correction of metabolic derangements. Hyperosmolar nonketotic coma is characterized by marked hyperglycemia in the absence of ketoacidosis and occurs usually in patients with mild adult-onset diabetes. Symptoms develop more slowly than in diabetic ketoacidosis. Treatment is the same for both conditions. In alcoholic ketoacidosis, hyperketonemia is present without hyperglycemia. The syndrome differs from diabetic ketoacidosis in that blood glucose levels are lower and glycosuria is absent. Treatment consists of intravenous administration of dextrose in water and, if necessary, of sodium bicarbonate. Insulin administration usually is not necessary. |
The molecular mechanism of the Bohr effect is explained according to the molecular model proposed by Perutz et al. The Bohr effect is due to changes in the pK of specific carboxyl and amino groups of the four globin chains following the transition between the deoxy and oxy conformations of the molecule. Carbon dioxide binds to the N terminal valine of the 4 monomers to form carbamino compounds. This carbaminoformation depends upon pH, PCO2 and predominates on deoxygenated haemoglobin. It is lowered when O2 binds to the heme groups (O2 linked carbamino compounds). Through the carbamino compounds Carbon dioxide lowers both the affinity of haemoglobin for O2 and the Bohr effect. Diphosphoglycerate also binds to the haemoglogin molecule. This organophosphate lowers the affinity for O2 but increases the Bohr effect. In whole blood, the Bohr effect is therefore dependent upon pH, O2 saturation, PCO2 and DPG concentration into the red blood cells. |
Propranolol, alprenolol and sotalol given intraventricularly (ivc) to rats reduce depressing effects of isoprenaline (IPS) and antagonize stimulating effects of noradrenaline (NA). Phentolamine given by the same route of administration does not affect IPS action. |
In vitro, the affinity of Hb for O2 depends on pH and capnia by the intermediate of the 2-3 DPG level, the concentration of which lowers in the case of acidosis and hypercapnia. Thus, an increase in the affinity results, but while Bohr's effect is immediate, on the contrary the 2-3 DPG effect is slow. Authors have verified the importance of this modification by studying the affinity of Hb for O2 thanks to the P50 technique in 15 normal non-smokers subjects and in 10 subjects with compensated or not respiratory acidosis but normally saturated thanks to continuous O2 administration. |
The effects of alpha, alpha1-dipyridyl (DP) on noradrenaline (NA), dopamine (DA) and 5-hydroxytryptamine (5-HT) levels in rat and mouse brain and on dopamine-beta-hydroxylase (DbetaH) activity in rat brain have been studied, DP decreases NA level and inhibits DbetaH activity in a dose dependent manner, without affecting DA or 5-HT levels. |
New colorimetric procedure for determination of bromisoval and carbromal is based on the hydroxamation reaction and colour developing after addition of Fe(ClO4)3. The method is employed for the estimation of both compounds in substances and in tablets. |
The influence of aeration, pH and iron concentration on the growth of yeast C. lipolytica 704 on the hexadecane medium and on the synthesis of citric and isocitric acids was investigated. The yeast synthesized citric acids actively during intensive aeration. The acid formation was strongly dependent on the medium acidity: pH 6.0 was most favourable for the synthesis of citric acids. The Fe concentration influenced significantly the ratio of the acids synthesized. At a low concentration of iron (0.005 mg Fe/l) equal amounts of citrate and isocitrate were formed; at an increased concentration isocitrate was in predominant formation. |
The transformation of inosine into 5'-inosine acid by Pseudomonas trifolii cells was studied. The synthesis of 5'-inosine acid can be performed by both live intact and dry cells. The effectiveness of inosine phosphorylation depends on the ratio of the inosine and phosphate donor concentrations and the amount of cells. The temperature and pH effect on activity of nucleoside phosphotransferase, phosphomonoesterase and 5'-nucleotidase has been studied. The influence of surface active substances and metal ions on the synthesis of 5'-inosine acid has been investigated. Optimal conditions for the inosine transformation by the above culture have been established. |
The purpose of the study was to determine optimal pH values for the enzymic activity of the fungi Trichothecium roseum and Aspergillus niger hydrolyzing nonstarch polysaccharides of barley and disrupting cell walls (cytolysis) of grain, the so called cytolytic enzymes. The effect of the acidity of the medium on the stability of these enzymes was also investigated. In this connection total cytolytic activity (i. e. total activity of the enzymes hydrolyzing nonstarch polysaccharides of cell walls of barley) and hemicellulase activity of the fungi at different pH values were measured. The activity of these enzymes in aqueous extracts from the fungal culture at optimal pH after preincubation was determined at different acidity levels. The optimum of the hemicellulase activity of both fungi was at 4.6, the optimum of the total cytolytic activity of Tr. roseum at pH 5.6 and of Asp. niger at pH 3.0. The enzymes of the fungus Asp. niger showed a far higher acid stability than those of Tr. roseum. |
By isoelectric focussing the lyzing complex produced by Actinomyces griseinus-11 has been fractionated. The sole neutral protease which is active at pH 7.0 does not participate in lysis induced by other enzymes. The lyzing activity of this complex is associated with the carbohydrase enzymes that are at least three in number. Various carbohydrases may exert a synergistic effect upon their combined action on the protein-vitamin concentrate. |
Thiamine pyrophosphokinase (EC 2.7.7.2) isolated from dry brewing yeast has been purified 20-fold with a 70% yield. Certain properties of the enzyme have been determined: pH and temperature optima, donor and acceptor concentrations, and relationship between the rate of cocarboxylase biosynthesis and the incubation time and the enzyme quantity. The effects of concentrations of bivalent metal ions Co2+, Mg2+ and Mn2+ on the rate of the enzymic reaction has been studied. A change in the pH optimum as a function of the nature of the ion-activator has been investigated. It has been shown that neopyrithiamin is a competitive inhibitor and oxythiamin inhibits the enzymic reaction insignificantly. Thiamine phosphate cannot be transformed into thiamine diphosphate by the purified enzyme. |
The formation of an insoluble product of the interaction of trypsin and sodium alginate at pH 3-9 was studied. The optic density of the system was in an extreme relation to the composition. The insoluble phase was enriched in trypsin. The dispersion phase formed as a result of the electrostatic interaction between alginate macroanion and trypsin macrocation. The interaction brought about the formation of ATn, where n=90-900 (with an accuracy of the term Mw/Mn of alginate). The relation between the composition of the complex and pH was nonmonotonous. |
The paper describes studies of heat treatment of the preparations amylorizin G10x, amylosubtilin G10x and glucoendomycopsin G15 and its effect on the relationshop between the rate of the enzymic reaction and the preparation concentration, optimal pH and temperatures, and the EDTA influence on the activity of heated preparations. After heating the preparations showed an elevation of optimal temperatures of their action and a shift of optimal pH to the alkaline region. Primary heating of the preparations resulted in an increase of the rate of the enzymic reaction. Heated preparations were less susceptible to the effect of the inhibitor that nonheated ones. |
The effect of hydrogen and hydroxyl ions on the physiological features of the yeast C. utilis VKMU-1668 was studied. High acidity inhibited yeast growth and uncoupled pathways of the energy and constructive metabolism: normal respiration was disturbed and the electron transport chain was damaged in the site of cytochromes and not flavins. Hydroxyl ions also inhibited yeast growth and uncoupled pathways of the energy and constructive metabolism: oxygen uptake and the content of flavin adenone dinucleotide increased, dehydrogenase activity upon the use of glycerol decreased significantly, and the absolute amount of all cytochromes declined slightly. The chemical composition of cellular polymers at all pH values tested was stable enough. The amount of major metabolites--volatile oils and ketoacids--was insignificant. |
The procedure for isolating aminoacyl-tRNA-synthetases from yeast Candida utilis IBPM-405 was developed. The rate of activation of L-amino acids in the formation of hydroxamates was different. Aspartic acid, asparagine, glutamic acid, tryptophane, phenyl alanine and methionine underwent the highest activation. The activation of alanine, arginine, hydroxyproline, serine and isoleucine was insignificant. Using aspartic acid, it was shown that the hydroxamate formation was ATP-stimulated and that the amount of hydroxamate increased with a rise of the protein concentration in the mixture to 9-10 mg/ml. The hydroxamate formation was inhibited by p-chloromercury-benzoate and heavy metal ions. Yeast aminoacyl-tRNA-synthetases showed L-aspartic and L-glutamic activities that were independent from Mg++ ions and ATP. |
Immobilized trypsin and alpha-chymotrypsin were obtained as a result of the enzyme attachment to bromo-cyanogen activated cepharose. Proteolytic activity (substrate--casein) of immobilized trypsin and alpha-chymotrypsin was 18.7 and 9%, respectively and their esterase activity with methyl ester benzoyl-L-arginine (trypsin) and ethyl ester acetyl-L-tyrosine (alpha-chymotrypsin) was 75 and 20% of that of soluble enzymes. Immobilized enzymes were used to purify proteinase inhibitors from potatoes by affine chromatography. Specific activity of trypsin and chymotrypsin inhibitors was increased 10 and 6 times, respectively. By isoelectric focussing it was shown that the purified preparation of chymotrypsin inhibitors consisted of two acid proteins and one alkaline protein, the latter being in predominance. The purified preparation of trypsin inhibitors contained equal amounts of proteins with the isoelectric point at pH 7.1 and 8.9 and a low quantity of the component with the isoelectric point at pH 5.7. |
The proteolytic preparation of Mucor pusillus-917 has been obtained. The preparation produces an effective hydrolytic influence on milk casein. Thermal and acid inactivation of the proteolytic complex is the reaction of the first order. The activity-pH curves, calculations of ionization heat, inactivation of proteases by photooxidation and monoiodoacetic acid suggest that imidazole, carboxyl and sulphydryl groups of proteases are involved in the clotting and hydrolysis of milk. |
The effect of low pH values on the activity and stability of the quaternary structure of asparaginase from Escherichia coli was investigated at early stages of purification of the enzyme. Acidification of the E. coli extract was most effective before the biomass separation. This procedure helped to separate biomass together with coagulated ballast proteins and not to reduce the activity. Upon storage of the acidified solution at 5 degrees C reversible dissociation of the tetrametric structure into dimers and monomers occurred. Stability of L-asparaginase in the storage of acetone powders and during extraction was studied. It is suggested that asparaginase in bacterial cells in unlikely to have the quaternary structure which normally occurs in the solution at neutral pH. |
A preparation with a high proteolytic activity has been obtained by acetone precipitation from the culture liquid filtrate of the thermophilous actinomycete Actinomyces thermovulgaris str. T-54. The proteolytic (caseinolytic), fibrinolytic and thrombolytic activity of the preparation is comparable with that of trypsin and far superior to that of fibrinolysine. The preparation is stable at pH 5.0=9.5 and inactivated in the acid zone. The study of pH dependent proteolytic activity has shown acid, neutral and alkaline proteases in the preparation. It is relatively thermostable, and is completely inactivated for 10 min at 90 degrees. It is suggested that the preparation contains four enzymes or four enzymic groups that are different in their temperature sensitivity. |
The effect of ammonium on glutamine synthetase of fodder yeast Candida tropicalis was studied. Ammonium ions were found to repress the synthesis of glutamine synthetase of fodder yeast and to inhibit the enzyme in the cells. The substitution of glutamic acid for ammonium in the nutrient medium brought about depression of glutamine synthetase. |
The properties of the thermotolerant fungus Rhizopus microsporus strain UzLT-1--producer of lipolyptic enzymes are described. Optimal cultivation conditions--40 degrees, C, pH 4.5--Are determined. The lipolytic activity of the culture on the medium consisting of corn extract (2%), cotton-seed oil (1%) and water is 850 ml 0.1 n KOH per 100 ml culture liquid. The enzymic preparations of lipase have been precipitated by isopropanol and ammonium sulphate. The preparation precipitated by isopropanol shows its macimum activity at pH 4.2 and 7.8 and a temperature of 40--50 degrees C. |
The capacity of 86 strains of the Aspergillus fungus to synthesize acid stable alpha-amylase was examined. The strains of Asp. niger showing a high capacity of synthesizing the enzyme were isolated. Repeated cultivation of the selected cultures on the Minoda agar medium led to a 200% increase in the enzyme activity in the submerged culture. Addition of sodium nitrate to the Minoda medium during submerged cultivation allowed a 3-fold increase of the synthesis of acid stable alpha-amylase. |
The specific action and composition of the functional groups of active centres of three fractions of acid proteinases from Aspergillus terricola have been studied. With respect to the hydrolysis rates of acetyl-L-phenylalanyl-L-tyrosine and carbobenzoxy-D, L-glycyl-phenylalanine by the three fractions it is suggested that the interaction of acid proteinases with the substrate involves hydrophobic forces. It has been shown that the above fractions are no metal enzymes. By means of the diazocarbonyl inhibitor an occurrence of a catalytically active carboxy group has been found in the active centre of proteinases. The proteinase inhibition by Fe3+ in the presence of citric acid is an indirect evidence of the existence of several carboxy groups and, possibly, of a hydroxy group in the active centre of acid proteinases from Aspergillus terricola. |
The stability to heating and pH changing of two proteinases of Bacillus subtilis was studied. The preparations were: protosubtilin G10x with an activity of 21500 units/g and proteinase immobilized on silochrome C-80 with an activity of 3880 units/g. For protosubtilin G10x the pH optimum was 7.0-7.2. For the immobilized preparation 96-100% activity was found at pH 5.5-10.0. The difference between the two proteinase preparations was more distinct with respect to the temperature minimum. The initial preparation-protosubtilin G10x was more stable to low temperature and showed maximum activity at 40 degrees; the immobilized preparation was less active at low temperatures and showed maximum activity at 60-70 degrees. Protosubtilin G10x was more sensitive to pH changes, especially in the acid zone (pH 4.5). It was significantly activated at 30-40 degrees and was unstable at 50-60 degrees. The immobilized preparation was activated at 50- 60 degrees and was insensitive to pH changes in the range of 4.5 to 9.2 and temperature changes from 10 degrees to 40 degrees for 1.5-2.0 hours. |
We have examined three mutants of Klebsiella aerogenes whose genetic lesions (glnB, glnD, and glnE) are in loci unlinked to the structural gene for glutamine sythetase (glnA) and in which the control of both the level and state of adenylylation of glutamine synthetase is altered. Each mutation alters a different component of the adenylylation system of glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2]. Inability of the cell to deadenylylate glutamine synthetase (glnB and glnD) greatly decreases its production, while inability to adenylylate glutamine sythetase (glnE) results in its constitutively high production. These results together with our previous results indicate that adenylylated glutamine synthetase inhibits the transcription of glnA. |
Fungal beta-galactosidase was immobilized by covalent binding with KM-cellulose. The resultant preparation contained 3 mg protein per 1 g carrier; its specific activity was 65% of the initial one. As a result of immobilization pH optimum remained unchanged whereas the temperature optimum decreased from 65 degrees to 50 degrees. The seemings Km of the immobilized enzyme varied insignificantly as compared with Km of the soluble enzyme. |
The conditions for splitting protodioscine--the main steroid saponine isolated from Tribulus terrestris L. by the enzymic preparation of Aspergillus niger str. BKMt-33 were investigated. The optimal conditions were found to be as follows: pH 4-5, temperature 30-37 degrees (the substrate concentration--5 mg%, concentration of the enzymic preparation--1%). Under these conditions the enzymolysis continued 24 hours. Mg+2 and K+ ions accelerated the reaction twice. As a result of the enzymic hydrolysis dioscine and trilline were obtained. This indicates beta-glucosidase and alpha-rhamnosidase activities of the enzymic complex isolated from Aspergillus niger str. BKMt-33. |
Clonal mouse neuroblastoma cells without tyrosine 3-monooxygenase [EC 1.14.16.2; tyrosine hydroxylase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating)] activity were fused with normal cells from embryonic mouse sympathetic ganglia. One of the 37 hybrid cell lines obtained possesses high tyrosine 3-monooxygenase activity and synthesizes dopamine. These cells also have excitable membranes and generate action potentials in response to electrical stimuli. Thus hybrid cells, generated by fusion of neuroblastoma cells with normal cells from the nervous system, can acquire neural properties not found with the parental neuroblastoma cells. |
Under aerobic conditions that are likely to prevail in chloroplasts in vivo, the optimal concentration of ferredoxin for cyclic photophosphorylation was found to be equal to that required for NADP reduction and about one-tenth of that needed for cyclic photophosphorylation under anaerobic conditions. In the presence of ferredoxin and NADP, cyclic photophosphorylation operated concurrently with noncyclic photophosphorylation, producing an ATP: NADPH ratio of about 1.5. The effective operation of ferredoxin-catalyzed cyclic photophosphorylation by itself required a curtailment of the electron flow from water which was accomplished experimentally by the use of either an inhibitor or far-red monochromatic light. An unexpected discovery was that the operation of cyclic photophosphorylation by itself was also regulated by a back reaction of NADPH and ferredoxin with two components of chloroplast membranes, component C550 and cytochrome b559. The significance of these findings to photosynthesis in vivo is discussed. |
High resolution 31P nuclear magnetic resonance (NMR) spectra at 145.7 MHZ are presented for intact yeast cells. Several peaks are resolved and assigned. They include the middle phosphate peaks from long chain or cyclic polyphosphates. Our results are consistent with the suggestion that these polyphosphates act as a phosphate store in the cell. We have also been able to measure cytoplasmic pH using the orthophosphate peak inside the cell, as compared with outside the cell. The results show that yeast cells maintain their cytoplasmic pH around 6.3. This value is considerably higher than the acidic extracellular pH at which they normally live. These preliminary results indicate that 31P NMR at 145.7 MHZ can be a rapid, informative, and non-invasive method for probing biochemical events within living cells. |
Stimulation with phytohemagglutinin of the leukocytes from six of the seven known individuals with UDP-galactose 4-epimerase (= UDP-glucose 4-epimerase; EC 5.1.3.2) deficiency consistently resulted in the appearance of epimerase activity in the cultured cells. A long-term lymphoblast culture derived from one proband also contained an active epimerase enzyme. A comparison of the properties of this enzyme with those of epimerase produced by control lymphoblast lines revealed comparable Km values for UDP-galactose and NAD and identical behavior on polyacrylamide electrophoresis. However, a difference in the NAD requirement for heat stability at 40 degree provided some evidence for a structural defect in this enzyme. Possible explanations for the appearance of UDP-galactose 4-epimerase activity in stimulated lymphocytes include an increased rate of synthesis of a mutant enzyme and a derepression of an epimerase locus during lymphocyte transformation. |
beta-Bungarotoxin, a pre-synaptic neurotoxin isolated from the venom of the snake Bungarus multicinctus, has been shown to modify release of neurotransmitter at the neuromuscular junction. In this communication, we demonstrate that beta-bungarotoxin is a potent phospholipase A2 (phosphatide 2-acyl hydrolase, EC 3.1.1.4), comparable in activity with purified phospholipase enzymes from Naja naja and Vipera russellii. The phospholipase activity of beta-bungarotoxin requires calcium and is stimulated by deoxycholate. When strontium replaces calcium, no phospholipase activity is detected. Since neuromuscular transmission is not blocked when calcium is replaced by strontium, it was possible to examine the effects of the toxin on neuromuscular transmission in the presence of strontium. Under these conditions, when the phospholipase activity should be inhibited, the toxin has little or no effect on neuromuscular transmission. If beta-bungarotoxin owes its toxicity in part to its enzymatic activity, then it must be placed in a different class from those toxins which produce their effect by binding passively to an appropriate receptor. |
An unsaturated fatty acid-requiring mutant derived from Chinese hamster ovary (CHO) cells has been isolated and characterized. This mutant grows normally when oleate or other unsaturated fatty acids are supplemented in the growth medium. Unlike the wild-type CHO cells, growth stops when medium is deprived of unsaturated fatty acid. Whole cell pulse experiments with [14C]acetate or [14C]stearate indicate that the mutant is defective in unsaturated fatty acid synthesis. Enzyme assays in vitro show that the enzymatic defect of the mutant is localized to the microsomal stearoyl-CoA desaturase. |
The method of DNA alkaline elution was applied to a study of the formation and resealing of DNA single-strand breaks after irradiation of human fibroblasts with ultraviolet light (UV). The general features of the results were consistent with current concepts of DNA excision repair, in that breaks appeared rapidly after UV, and resealed slowly in normal fibroblasts, whereas breaks did not appear in those cells of patients with xeroderma pigmentosum (XP) that are known to have defects in DNA repair synthesis. The appearance of breaks required a short post-UV incubation, consistent with the expected action of an endonuclease. Cells of the variant form of XP characterized by normal DNA repair synthesis exhibited normal production of breaks after UV, but were slower than normal cells in resealing these breaks. This difference was enhanced by caffeine. A model is proposed to relate this finding with a previously described defect in post-replication repair in these XP variant cells. DNA crosslinking appears to cause an underestimate in the measurement of DNA breakage after UV. |