bluuebunny/crossref_metadata_2025 huggingface dataset:
BACTERIAL CELL MEMBRANES: II. POSSIBLE STRUCTURE OF THE BASAL MEMBRANE CONTINUUM OF MICROCOCCUS LYSODEIKTICUS
Authors: Grula E. A. , Butler Thomas F. , King Robert D. , Smith Gerald L.
Published: February 2010

Treatment of isolated membranes from M. lysodeikitcus with acetone, ethanol, or methanol, but not ethyl acetate, extracts phospholipids and carotenoids. These extracted membranes are not disaggregated by such treatments and retain a three-layered appearance. The extracted membranes can be completely disaggregated by sodium lauryl sulfate, yielding subunits which are primarily protein (stripped subunits). These stripped subunits reaggregate into membranous sheets that also possess a three-layered structure. Conditions for reaggregation of stripped subunits are the same as for unstripped subunits. Extracted phospholipids and carotenoids from M. lysodeikitcus or phospholipids from Erwinia sp. are incorporated into the membranous sheets formed using the stripped subunits from M. lysodeikticus. The composition of the basal membrane continuum from M. lysodeikticus consists primarily of protein; most phospholipids and carotenoids appear to be present as superstructures on the top and bottom of the protein. Membrane protein is basic and does not appear to contain any cysteine. It is speculated that hydrophobic amino acids may be positioned in clusters on the facing sides of the molecules.
MARINE THIOBACILLI: II. CULTURE AND ULTRASTRUCTURE
Authors: Tilton R. C. , Stewart G. J. , Jones G. E.
Published: February 2010

Gram-negative, polar-flagellated bacteria isolated from the Atlantic Ocean using thiosulfate or elemental sulfur as the sole energy source are considered members of the genus Thiobacillus. These cultures require seawater in the medium although they grow optimally when the salinity is reduced to a range of 6.4 to 25.8 p.p.t. There is no growth at 0 salinity and a 25–30% reduction of thiosulfate oxidation in 3 weeks is observed at 18 °C in a salinity of 32.3 p.p.t. The pH of the medium decreased from 7.2 or 5.6 to a final pH of 2–3. One culture decreased the pH to only 5.0 while oxidizing 80% of the thiosulfate. One representative culture, WH-2, was able to oxidize only thiosulfate and elemental sulfur from a series of substrates including tetrathionate, sulfite, sulfur-containing amino acids, and mineral sulfides. This culture is a strict aerobe and did not grow in the presence of 0.01% yeast extract, 2216E, or nutrient broth.The ultrastructure of culture WH-2 indicates that it is very similar to that of Thiobacillus thioosidans. The cells indicate a substantial cell envelope, cytomembranes, electron-dense fibrillar nuclear material, unknown granules, and distinct polyphosphate granules.
STUDIES ON THE CULTIVATION OF LISTERIA MONOCYTOGENES IN BATCH AND CONTINUOUS CULTURES
Authors: Holmström Björn
Published: February 2010

The growth of Listeria monocytogenes, McGill strain 42, XXVIII, has been studied in batch and in continuous cultures on a tryptose broth. Yields of 1.5 g dry weight/1 were obtained after 12 h of cultivation in semianaerobic batch cultures and the same yields were obtained in continuous cultures with a dilution rate of 0.25 h−1. Automatic pH control proved essential to achieve these values. Most cultures were run at 37 °C, but one culture at +4 °C is also reported. For large-scale production of cells, batch cultures of 500–2200 1 were run as well as 0.8–75 1 continuous cultures.
THE BIOLOGICAL PROPERTIES OF 3,6-EPIDITHIADIKETO-PIPERAZINES. DEGRADATION OF GLIOTOXIN-B BY BACILLUS SUBTIL IS (HLX 373)
Authors: Brewer D. , Taylor A.
Published: February 2010

Like sporidesmin, gliotoxin catalyzes the decomposition of azide in the presence of iodine, and this catalysis can be used for its estimation. The presence of respiring cells of Bacillus subtilis does not interfere with the estimation. Thus it was possible to show that the concentration of gliotoxin decreased when solutions of the antibiotic were incubated with respiring cells. The rate of the decomposition was independent of the gliotoxin concentration in the range 2–25 μg/ml, but was dependent on the number of cells, the pH, and the available nitrogen in the suspending medium. Loss of gliotoxin was most rapid at pH 5.5 and continued when the supernatant was reincubated after centrifugal removal of the cells. No loss of gliotoxin occurred when solutions were incubated in the absence of cells at pH 5.5. By contrast, chemical degradation at pH 8.0 was inhibited in the presence of cells. These results are consistent with the hypothesis that B. subtilis secretes an enzyme which degrades the disulfide group in gliotoxin.
D-GLYCERO-D-MANNO-HEPTOSE AS A COMPONENT OF LIPOPOLYSACCHARIDES FROM GRAM-NEGATIVE BACTERIA
Authors: Adams G. A. , Quadling C. , Perry M. B.
Published: February 2010

Lipopolysaccharides have been isolated from seven species of Gram-negative bacteria and their acid hydrolysates have been examined by gas–liquid partition chromatography for the presence of aldoheptoses. All contained D-glycero-D-manno-heptose in addition to the well-known aldoheptose component L-glycero-D-manno-heptose. The relative proportions of these two aldoheptoses varied widely between species of bacteria and to a lesser extent between members of the same species. Both aldoheptoses were isolated from a lipopolysaccharide prepared from E. coli cells and were positively identified by physical and chemical methods. The chromatographic method used for determining the aldoheptoses also provided means for simultaneous detection of 3-deoxy-D-manno-octulosonic acid (KDO).
METABOLISM OF LEPTOSPIRES: II. THE ACTION OF 8-AZAGUANINE
Authors: Johnson Russell C. , Rogers Palmer
Published: February 2010

Both the pathogen Leptospira pomona and the saprophyte L. biflexa Patoc I can convert exogenous adenine, guanine, and 8-azaguanine to the corresponding nucleotide and incorporate them into nucleic acids. L. pomona is inhibited by low concentrations of 8-azaguanine (50 μg/ml) and this inhibition is associated with less than a 5% replacement of the ribonucleic acid (RNA) guanine residues by the analogue. Guanine possessed the highest activity for antagonizing the inhibitory effect of 8-azaguanine. The biosynthetic process of L. pomona most affected by the analogue was a relative increase in RNA synthesis. The analogue-resistant L. biflexa incorporated 1/10 as much 8-azaguanine as L. pomona. The higher rate of purine biosynthesis, in addition to the lesser amount of 8-azaguanine incorporated, may account for the analogue resistance of L. biflexa.
ETHANOL PRODUCED BY AUREOBASIDIUM PULLULANS AND ITS EFFECT ON THE GROWTH OF ARMILLARIA MELLEA
Authors: Pentland Gertrude D.
Published: February 2010

The cell-free filtrate of a liquid culture of Aureobasidium pullulans (de Bary) Arnaud contained a substance which stimulated the growth of Armillaria niellea (Fr.) Quél. This stimulatory effect was apparent when either rhizomorph tips or undifferentiated mycelium on water agar discs were used as inoculum, indicating an effect on both rhizomorph initiation and elongation. The cell-free filtrate was shown by gas chromatography to contain ethanol. Ethanol had an effect on the growth of A. mellea similar to that of the cell-free filtrate.Growth of A. mellea was stimulated by the presence of ethanol in the medium and the degree of stimulation was shown to be dependent on the total amount of ethanol available at a concentration of 500 p.p.m. Ethanol added at regular intervals as lower concentrations in the medium stimulated the growth of A. mellea as much as one higher initial concentration. A concentration of ethanol as low as 50 p.p.m. added daily for 14 days was more effective than an initial concentration of 700 p.p.m. in stimulating rhizomorph development of A. mellea.
EFFECTS OF TANNINS ON SPORE GERMINATION AND GROWTH OF FUSARIUM SOLANI f. PHASEOLI AND VERTICILLIUM ALBO-ATRUM
Authors: Lewis J. A. , Papavizas G. C.
Published: February 2010

Gallotannin, wattle, canaigre, and chestnut tannins in a complete medium affected in vitro spore germination and mycelial growth of Fusarium solani f. phaseoli and Verticillium albo-atrum. The pH values and tannin concentration were important factors determining the effectiveness of tannins as inhibitors. Under acidic conditions (pH 5), gallotannin, canaigre, and chestnut tannins at concentrations varying from 39 p.p.m. to 625 p.p.m. inhibited spore germination of both fungi. At a concentration of 1000 p.p.m. these tannins completely prevented growth at pH 5 of both fungi during a 20-day period. Under near neutral conditions (pH 6–7) there was a minimum inhibition of spore germination and mycelial growth with all tannins tested. Under alkaline conditions (pH 8) there was some degree of inhibition of spore germination, but, in general, growth was similar to that under neutral conditions. Wattle tannin was unusual in that it did not prevent growth of either fungus under acidic conditions although the growth of V. albo-atrum was appreciably reduced compared with the control. Gallotannin, however, prevented growth of both fungi under alkaline as well as acidic conditions.
DISTRIBUTION OF HEAT-LABILE AND HEAT-STABLE INORGANIC PYROPHOSPHATASES AMONG SOME BACTERIA
Authors: Blumenthal Bernard I. , Johnson Mary K. , Johnson Emmett J.
Published: February 2010

Significant biochemical differences were found in the inorganic pyrophosphatases from different bacteria. All of the Gram-positive sporeforming rods tested possessed a constitutive, heat-labile enzyme, and all of the Gram-negative rods tested possessed a constitutive, heat-stable enzyme. Of the enzymes from the Gram-positive cocci studied, the enzymes from two species of the genus Streptococcus were constitutive and heat labile, the enzyme from Micrococcus lysodeikticus was inducible and heat stable, and that from Staphylococcus aureus was inducible and heat labile. The enzyme from Mycobacterium phlei, the only acid-fast organism studied, was constitutive and heat labile.
Effects of immunosuppressive drugs on secondary antibody response in vitro
Authors: Leung F. C. , Vas S. I.
Published: February 2010

The inhibitory effects of 6-mercaptopurine, Imuran, and chloramphenicol on the in vitro incorporation of radioactive amino acid into antibody have been investigated. Inhibition of antibody synthesis by these drugs was compared to inhibition of protein synthesis within the same tissue cultures. The relative inhibition of antibody synthesis compared to that of protein synthesis provided an index which indicated the specificity and toxicity of the immunosuppressive agent. Imuran, at concentrations of 10–20 μg/ml inhibited antibody synthesis primarily, while at higher concentrations, protein synthesis was similarly affected. 6-Mercaptopurine at 177–250 μg/ml inhibited antibody production to a certain degree, while chloramphenicol at 300 μg/ml showed no preferential inhibition of antibody synthesis.
Transmission of California encephalitis virus by mosquitoes
Authors: Chernesky Max A.
Published: February 2010

Transmission of California encephalitis (CE) virus strain R2929 by groups of Aedes vexans (Meigen) mosquitoes to rabbits was accomplished 7 and 9 days after the insects had imbibed an infective blood meal. Aedes aegypti (L.) mosquitoes transmitted virus to newly hatched chickens by biting them 48, 96, and 144 hours after intrathoracic injection.CE vires was found in gut, thorax, legs, and salivary glands of pools of Aedes triseriatus (Say), Aedes canadensis (Theobald), and A. vexans mosquitoes after intrathoracic injection of 101.3 mouse LD50 per 0.003 ml of virus. Salivary glands contained a maximum virus titer of 105.0 mouse LD50 per anatomical unit 5 days after injection. A. aegypti mosquitoes also supported virus growth after intrathoracic injection but yielded higher virus titers (106.3 mouse LD50) in the salivary glands.The infection threshold of A. vexans fed CE virus was 102.0LD50 per insect. Immediately after ingestion of 102.0 LD50 of virus only the gut washings contained virus. Detection of virus was not accomplished again until 4 days later. Average maximum titers of 104.5 LD50 per salivary glands were found after 8 days of extrinsic incubation. The infection threshold of A. aegypti fed CE virus exceeded 104.5 LD50 per insect.New Zealand white rabbits and Leghorn chickens circulated CE virus in their blood, which attained peak titers of 102.5 mouse LD50 per 0.03 ml 48 and 72 hours respectively after subcutaneous inoculation, but weaned mice did not develop viremia. All three animal species produced neutralizing antibodies to CE virus 21 days after inoculation.
Nitrogen fixation by cell-free extracts of Klebsiella pneumoniae
Authors: Mahl M. C. , Wilson P. W.
Published: February 2010

A cell-free system which permits nitrogen fixation by extracts of Klebsiella pneumoniae M5al (formerly Aerobacter aerogenes) has been developed. It is, essentially, that system described by Bulen and associates for Azotobacter vinelandii, utilizing ATP as a source of energy and dithionite as a source of electrons. The Michaelis constant for fixation has been estimated to be 0.12 atm. The extracts possessed an ATP-dependent hydrogen evolving system. Hydrogen evolution from these extracts was less under nitrogen than under helium in the presence of ATP. Nitrogen gas appears to be the inducer of nitrogen fixation. In the absence of N2, no induction of nitrogenase occurs. Nitrogenase is absent in cells grown on NH4+-N. There is a lag of about 13 h after the introduction of N2 gas into a culture which has depleted its supply of NH4+-N before nitrogenase can be detected. For reasons discussed in the text, this conclusion must be regarded as tentative at this time. Ammonium ion appears to prevent the synthesis of new molecules of nitrogenase without affecting the activity of those already formed.
Effects of exogenous purines on growth rates and other properties of Staphylococcus aureus strains including a pyrimidineless mutant of the Wood 46 strain
Authors: Repentigny J. de , Mathieu L. G. , Turgeon S. , Sonea S.
Published: February 2010

Growth inhibition by adenine or adenosine and its reversal by other purines were quantitatively different in the four Staphylococcus aureus strains we have studied. After 11 hours, 0.25 μmole/ml adenine or adenosine reduced growth by 6 and 4%, respectively, in the coagulase-negative SA-13 strain, by 35 and 35% in the tryptophan-dependent Smith strain, by 68 and 98% in a Wood 46 thymineless mutant strain, and by 40 and 37% in the parent Wood 46 strain. Normal growth in the presence of adenine or adenosine was restored in most cases by guanine, guanosine, hypoxanthine, inosine, and inosinic acid. However, for the thymineless mutant strain, guanine and inosine were much less effective in this respect in the presence of adenine, and none of these purines could reverse the inhibitory effect of adenosine. Purine analogs were mostly ineffective in inhibiting or in restoring growth. Our observations indicate that some patterns of purine biosynthesis and utilization in Staphylococcus aureus are different from those already known in other bacterial species. Adenine or adenosine had a greater inhibitory effect on the growth of coagulase-positive strains than on that of the coagulase-negative strain.
Investigations on the formation and interconversion of Sindbis virus hemagglutinins
Authors: Faulkner P. , Dobos P.
Published: February 2010

Three hemagglutinins were separated by equilibrium density centrifugation in CsCl of Sindbis concentrates obtained from infected chick-embryo cultures. They were designated heavy fraction (HF, density 1.240 g/ml), intermediate fraction (IF, density 1.212 g/ml), and light fraction (LF, density 1.191 g/ml). On the basis of work published by other authors, HF is considered to consist of Sindbis virions and LF to consist of non-infectious coreless particles and other membranous structures. The third hemagglutinin fraction, IF, appeared in the culture fluid at about the same time as the virions (HF) and before the non-infectious LF. In a series of rebanding experiments in CsCl gradients the relationship [Formula: see text] was demonstrated. The constant buoyant density of IF and results of the reconstitution experiments described suggest that IF consists of virions surrounded by LF material in a fixed and constant proportion. It is not established whether IF plays any role in the intracellular replication of the virus.
Immunodiffusion studies on the myxoviruses. I. The presence of influenza A/PR8 precipitins in the serum of some normal animals
Authors: Johnson C. Margaret , Westwood John C. N.
Published: February 2010

Precipitins against influenza A/PR8 were detected in the serum of normal rabbits with a highly sensitive cellulose acetate micro-immunodiffusion technique which allows the diffusion of whole virus particles. Rabbits were susceptible to subclinical artificially induced influenza A/PR8 infection. These natural antibodies might be indicative of natural infection in animal populations with influenza A/PR8 or a closely related influenza A strain. Similar immunodiffusion reactions were observed with normal serum from a sheep, a goat, guinea pigs, and roosters.
The response of sporogenesis in Bacillus subtilis to acriflavine
Authors: Rogolskyi Marvin , Slepecky Ralph A.
Published: February 2010

Previous studies demonstrated that acriflavine treatment of early log phase cells of Bacillus subtilis produced both stable oligosporogenic and asporogenic mutants in high yield. More recently it has been demonstrated that high numbers of oligosporogenic mutants, believed to be defective for a regulatory gene, were found consistently after acriflavine addition. The asporogenic mutants were found on only a few occasions at approximately 19 hours after the addition of acriflavine. Results did not imply that acriflavine selected out either type of mutant. Exposure of late log and stationary phase cells to acriflavine was not effective in producing sporulation mutants. However, if these cells grown to the late growth phase are irradiated with specific doses of ultraviolet light and then treated with acriflavine, high numbers of oligosporogenic mutants appeared. The acriflavine-induced Sp− mutants were not found to be auxotrophic for amino acids or resistant to acriflavine. They had no detectable respiratory deficiencies and produced the protease and bacteriocin associated with the early stages of sporogenesis.
Synthesis and degradation of intracellular polyglucose in Streptococcus salivarius
Authors: Hamilton Ian R.
Published: February 2010

The incorporation of large quantities of glucose into an intracellular polymer similar in composition to glycogen has been demonstrated with growing and resting cells of Streptococcus salivarius isolated from human saliva. Characteristics of the synthetic process have been determined with resting cells grown in minimal glucose broth and then incubated with glucose-14C in a nitrogen-free buffer medium. At an optimum pH of 7.0, cells rapidly synthesized large quantities of intracellular polyglucose incorporating glucose at an initial rate of 5.6 μmoles/h per mg dry weight of cells. At exogenous glucose concentrations of 11.0 μmoles per milligram dry cells or above, resting cells would not incorporate more than 2.75 μmoles of glucose into intracellular polysaccharide. The incorporation of this amount of glucose represents a 50% increase in cell size on a dry weight basis and reflects the physical limit of these cells without cell division. Almost 90% of this intracellular material was utilizable glucose in polymer form with the remaining material being incorporated into structural components. The enzymes for polyglucose synthesis were found to be constitutive, although the rate and degree of synthesis was reduced after prolonged exposure to carbon sources other than glucose, possibly reflecting an alteration in the glucose transport system. Growth at high levels of glucose also suppressed the rate of polyglucose synthesis as well as the rate of glucose utilization. Rapid degradation of the intracellular polyglucose was always observed in the absence of exogenous carbohydrate with the last molecules of glucose synthesized into the polymer being the first to be degraded upon exhaustion of the exogenous glucose. With resting cells of S. salivarius, the exogenous glucose not incorporated into polyglucose was stoichiometrically converted to lactic acid, but only 80–85% of the endogenous polyglucose was converted to this end-product in the absence of exogenous glucose, with the remaining 15–20% being degraded to small amounts of α-ketoglutarate, citrate, pyruvate, and an unknown acid. In this organism, intracellular polyglucose synthesis and degradation appear to be controlled processes, as experiments designed to measure the specific activity of lactic acid, produced by cells grown on high and low levels of glucose and metabolizing radioactive glucose, have shown that synthesis and degradation of intracellular polyglucose do not proceed simultaneously.
The stimulatory effect of Aureobasidium pullulans on rhizomorph development of Armillaria mellea in autoclaved soil
Authors: Pentland Gertrude D.
Published: February 2010

Armillaria mellea (Fr.) Quél, was able to develop an extensive rhizomorph system in autoclaved soil in two-section petri plates if the stimulatory substance produced by Aureobasidium pullulans (de Bary) Arnaud was present. A sufficient quantity of the substance was produced by A. pullulans on a glucose–asparagine agar substrate but not on an autoclaved soil substrate.
A simple plate test for the determination of protocatechuic acid utilization by soil bacteria
Authors: Sundman Veronica
Published: February 2010

The method described makes use of the color reaction between protocatechuic acid and ferric ions. Separately sterilized protocatechuic acid is added to soil extract agar before plates are poured. After suitable incubation the plates are flooded with ferric chloride solution. Colorless zones around growth contrasting with the green color of the protocatechuic acid containing agar indicate utilization of protocatechuic acid. With the aid of this method the frequency of strains that use protocatechuic acid, among random bacterial isolates of soil origin, was found to vary between 26 and 44% according to the soil investigated.
Metabolites of pathogenic fungi. VI. The isolation of 5-thiomethyladenosine from Candida albicans
Authors: Pace-Asciak C. , Just G. , Blank F.
Published: February 2010

The isolation of 5-thiomethyladenosine in greater than 14 μmoles per gram dry weight from Candida albicans is described.
The enhanced release of coxsackievirus B5 from a trypsinized monolayer of HEp-2 cells
Authors: Konowalchuk Jack , Speirs Joan I.
Published: February 2010

Comparative studies have been made of the extracellular release of coxsackievirus B5 from HEp-2 cells. The latter were maintained as monolayers or as freshly trypsinized cells, kept either in suspension or allowed to settle out. In accordance with some workers we have found that the suspended cells release virus earlier and in larger amounts than monolayer cells. We attribute and attempt to show experimentally that this difference, to a large degree, is the result of the physically round shape of the suspended cell as compared to the varied shape of the monolayer cell.
Properties of a D-quinovosamine-producing Achromobacter
Authors: Colwell R. R. , Smith E. J. , Chapman G. B.
Published: February 2010

The bacterial mucopolysaccharide of a Gram-negative bacterium, Georgetown strain COC-21, includes a hexosamine component, D-quinovosamine. The bacterium has been identified and classified as Achromobacter georgiopolitanum n. sp. and a description of the organism is given. The overall deoxyribonucleic acid base composition, determined by buoyant density measurements in cesium chloride, is 41 moles %. Electron micrographs of ultrathin sections reveal a double-layered cell wall structure typical of the Gram-negative bacteria.
Value of a plant growth retardant for isolating soil fungi
Authors: Curl E. A.
Published: February 2010

Various concentrations of 42 dyes, alkaloids, plant-growth regulators, and miscellaneous chemicals were tested as substitutes for rose bengal in peptone–dextrose–streptomycin agar for isolating soil fungi by the dilution-plate method. Most of the chemicals did not compare favorably with rose bengal, but a plant growth retardant 2,4-dichlorobenzyltributylphosfonium chloride (phosfon) used at 500 μg/ml significantly increased numbers of fungal colonies per plate and suppressed fast-growing fungi. The value of phosfon persisted even in the presence of gibrel, which alone induced rapid overgrowth of plates by Trichoderma and the Mucoraceae.
Ultrastructural comparisons of fungus hyphal cells using frozen-etched replicas and thin sections of the fungus Pyrenochaeta terrestris
Authors: Hess W. M.
Published: February 2010

The ultrastructure of P. terrestris hyphal cells was investigated to compare frozen-etched replicas with chemically fixed thin sections. The fungus used in this study uses glycerol as a sole carbon source and survives the freezing procedures necessary for freeze-etching; thus frozen-etched replicas reflect the living state.Frozen-etched membrane systems have particles of various sizes and concentrations and have a smooth appearance as contrasted to chemically fixed membrane systems, which have particles difficult to distinguish and somewhat irregular membrane systems. Frozen-etched cell walls are seen to contain particles, and microfibrillar orientation is evident in older cell walls, whereas substructure is not evident in chemically fixed cell walls, although secretion products of the fungus accumulate on cell surfaces.Chemically fixed ground cytoplasm has ribosomes and areas of high- and low-electron scattering which are not seen with freeze-etching. Cells fixed in glutaraldehyde–acrolein–OsO4 more nearly resemble frozen-etched cells than cells fixed in potassium permanganate.
Extracellular proteolytic enzymes of psychrophilic bacteria. II. Production and heterogeneity of enzymes of an obligately psychrophilic red-pigmented bacterium and of a white variant
Authors: Nunokawa Y. , McDonald I. J.
Published: February 2010

The appearance of proteolytic enzymes in culture fluids during growth of an obligately psychrophilic red-pigmented bacterium and of a white variant was followed. Enzymes were precipitated with ammonium sulfate and fractionated on Sephadex G-100. Both organisms produced a slow-moving component (III) at the start of proteinase production and a fast-moving component as the culture aged. The fast-moving component of the red but not of the white organism was separated into two fractions (I-1 and I-2) on DEAE-cellulose. On filtration through Sephadex, fraction I-1 gave rise to fraction III; fraction I-2 gave rise to enzymatically active I-2 and inactive red pigment. It is suggested that both organisms produce fraction III initially and that this aggregates to form fraction I-1 and that the red organism produces fraction I-2, which is a separate protein.
Infection bactérienne à Salmonella typhimurium chez un invertébré, Galleria mellonella L.
Authors: Kurstak E. , Vega C. E.
Published: February 2010

Fourth and fifth instar larvae of Galleria mellonella were inoculated by injection or "per os" with two strains of Salmonella typhimurium. After injection of 2 × 104 viable units, the average mortality was 68%, with strain 7 Suc LL, and 26% with strain LT2; by per os inoculation, mortality was 58% and 18% respectively. During infection, the number of bacteria increased and the total hemocyte count decreased by 64% with a consequent impairment of phagocytosis. Infection under similar conditions with a saprophytic Enterobacteriaceae species, Escherichia coli had no effect. Since the wax-moth infests beehives the possibility of Salmonella infection may be of epidemiological significance.
Use of normal probability paper in determining thermal melting values of deoxyribonucleic acid
Authors: Knittel M. D. , Black C. H. , Sandine W. E. , Fraser Dorothy K.
Published: February 2010

A method is described of plotting deoxyribonucleic acid (DNA) thermal melting data which allows information other than average content of guanine plus cytosine to be determined. Absorbancy (A) values, corrected for thermal expansion, are plotted on normal probability graph paper and the best straight line drawn. The 50 percentile point on the graph establishes the Tm value which allows calculation of the mean base composition. In addition the 2σ (twice the standard deviation) value is easily determined from the probability plot, thus providing information about the degree of variation from the mean in DNA base composition. Comparison of the probability plot and usual graphic methods of determining Tm values provided similar DNA composition data on 15 different strains of Streptococcus lactis, Streptococcus cremoris, and Streptococcus diacetilactis. When many A values obtained from streptococcal DNA samples showing skewed thermal melting curves (S. lactis b and S. diacetilactis DRC-2) were plotted on normal probability paper, two intersecting straight lines were apparent on the graph. This suggested that there were two types of DNA in these organisms. Each had its own unimodal compositional distribution and its presence was confirmed by density gradient separation. The use of normal probability plots as a rapid method of determining average base composition of DNA samples is suggested. In addition, heterogeneity in base composition may be shown by this method of plotting the data.
Identité immunochimique de certains polysaccharides extracellulaires chez diverses espèces de Rhizobium. I. Polysaccharides extracellulaires solubles de Rhizobium meliloti
Authors: Failly Christiane , Blachère H.
Published: February 2010

Ten strains of Rhizobium meliloti were compared by immunochemistry. A polysaccharide-precipitin band is identified by a specific staining method. The polysaccharide-precipitin band is common to the 10 strains of R. meliloti.
Selecting an economical binary test battery for a set of microbial cultures
Authors: Niemelä S. I. , Hopkins J. W. , Quadling C.
Published: February 2010

Selection of diagnostic tests for key construction from binary test-scores has been achieved (1) by evaluation of the partitioning effects of sequentially executed dichotomies and (2) by an exploratory process of data-matrix reduction. Corresponding computer programs are described and their results compared. Both procedures yielded similar, acceptable, keys when applied to data of various origins ranging in size from 9 cultures × 8 tests to 308 × 131. The matrix-reduction method was usually more economical of computer time. Some indications have been derived of the approximate number of such diagnostic tests likely to be needed in keys for given numbers of individuals. The actual number required in any instance will depend on the extent to which individual tests are correlated in the data. Consequently, overall performance of tests when associated in keys is not predictable from simple numerical indices expressing their divisive power.
A comparison between the effects of a surfactant (chenodeoxycholamine) and freezing and thawing on some properties of the membrane of Pseudomonas aeruginosa
Authors: Bernheim Frederick
Published: February 2010

Chenodeoxycholamine, a bile acid conjugated with a quaternary amine, increases the rate of swelling of cells of a strain of Pseudomonas aeruginosa suspended in 0.05 M Na–K phosphate buffer, pH 7.7. It also inhibits benzoate oxidase induction but only when the concentration of the buffer is increased. The rate of swelling in normal and treated cells apparently depends on the rate of influx of ions. Ion efflux may also occur in the presence of an oxidizable substrate. Freezing and thawing has effects similar to those of the drug. Low concentrations of ninhydrin or mercuric chloride inhibit the induction of benzoate oxidase. The inhibition is markedly decreased in drug-treated and frozen and thawed cells.
The effect of prewetting naturally infested soils on destruction of the muskmelon wilt fungus by formaldehyde
Authors: Wensley R. N.
Published: February 2010

The length of time muskmelon wilt soils were prewetted with water influenced the effectiveness of formaldehyde against populations of the wilt fungus, Fusarium oxysporum f. melonis, and as a control of wilt. Formaldehyde was least effective against populations of the wilt fungus in soils wetted for 24 hours before treatment and increasingly effective after 72 and 168 hours of wetting. Prewetting soils for different periods of time did not affect the susceptibility of Trichoderma and Penicillium spp. and members of Mucoraceae to formaldehyde.
An approach to the classification of lactobacilli using computer-aided numerical analysis
Authors: Seyfried Patricia L.
Published: February 2010

An electronic computer was used to analyze the data obtained for 82 strains of streptococci, lactobacilli, and propionibacteria. The lactobacilli were divided into three major taxonomic groups which correspond to the subgenera Thermobacterium, Streptobacterium, and Betabacterium described by Orla-Jensen (14). Three clusters observed among the streptococcal strains also correlate with Sherman's (19) classification of pyogenic, fecal, and lactic groups of streptococci. The results are in agreement with present classifications. No justification for including the genus Lactobacillus in the same family as genus Propionibacterium was found.
Loss of effectiveness and infectivity in mutants of Rhizobium resistant to metabolic inhibitors
Authors: Schwinghamer E. A.
Published: February 2010

Association between resistance to metabolic inhibitors and ability for symbiosis was investigated for isolates of Rhizobium blocked at different stages of nodule development. Approximately 530 spontaneous mutants were isolated from symbiotically effective strains (mainly R. leguminosarum and R. trifolii) for resistance to one of 21 inhibitors, mainly structural analogues of L-amino acids. Mutants resistant to fluorophenylalanine, norleucine, norvaline, D-leucine, D-methionine, D-histidine, or D-alanine comprised a group having several characteristics in common. Those derived from R. leguminosarum strains were typically non-nodulating (non-infective) on pea seedlings while those from R. trifolii strains were ineffective on red clover. Loss or non-loss of parental ability to form effective nodules could be predicted with about 85% accuracy on the basis of an additional criterion, namely collateral sensitivity to D-aspartic or D-glutamic acid. Limited bioassays for metabolic excretion showed no consistent change in excretion for any class of mutant. In some of the mutants, partial auxotrophy was associated with resistance to inhibitors; in one strain of R. trifolii the nutritional requirement appeared to be related also to loss of effectiveness. Loss of symbiotic ability was most pronounced for mutants resistant to amino acid antagonists which most readily induced spheroplast formation in culture. Cell wall or membrane defects are considered as one likely basis for ineffectiveness in these mutants.
Extracellular purine β-ribosidases from fungi
Authors: Reese E. T.
Published: February 2010

Purine β-ribonucleosidases are inducible enzymes secreted into the growth medium by several species of Aspergillus and Penicillium. They act on purine β-N-ribosides to produce p urine and ribose, but do not hydrolyze pyrimidine β-N-ribosides, deoxyribonucleosides, or β-O-ribosides. Nucleosidase g has properties different from nucleosidase a, one of which is the added ability to hydrolyze adenosine 5′-phosphate to adenine and ribose 5′-phosphate.
Production of polyol dehydrogenases in bacteria
Authors: Yamanaka Kei , Sakai Shuzo
Published: February 2010

D-Arabitol dehydrogenase (D-arabitol [Formula: see text]D-xylulose, D-arabitol:NAD oxidoreductase, EC 1.1.1.11) was found in the D-sorbitol-grown or D-mannitol-grown cells of Agrobacterium tumefaciens, Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas coronafaciens, Sarcina aurantiaca, and Sarcina marginata. This enzyme was accompanied by D-sorbitol dehydrogenase. Activity of D-mannitol dehydrogenase (D-mannitol:NAD oxidoreductase, EC 1.1.1) was also found in Pseudomonas fluorescens, Pseudomonas coronafaciens, Pseudomonas aeruginosa, Sarcina marginata, and Sarcina aurantiaca. D-Mannitol dehydrogenase was produced from Lactobacillus brevis, L. pentoaceticus, L. gayonii, and Leuconostoc mesenteroides in fructose media. D-Fructose seemed to be essential for the enzyme production by L. brevis, but Leuconostoc mesenteroides produced an equal amount of the enzyme from D-glucose, D-fructose, or sucrose media. Mannitol was found to be effective for enzyme production in a shake culture of Leuconostoc mesenteroides and of L. brevis.
Characterization of Streptococcus durans bacteriophages
Authors: Brailsford Marvin D. , Hartman Paul A.
Published: February 2010

Streptococcus durans bacteriophages were isolated from bovine rumen fluid, feed lot soil, bovine fecal samples, and lysogenic strains of S. durans. The presence of different phage strains was suggested by antiserum neutralization tests and one-step growth characteristics, whereby the bacteriophages were placed into three distinct, but serologically related, groups. These phages were further characterized by plaque morphology, phage morphology, adsorption kinetics, and pH and temperature effects.
Sulphur and carbon isotope fractionation by Salmonella heidelberg during anaerobic SO3= reduction in Trypticase soy broth medium
Authors: Krouse H. R. , Sasaki A.
Published: February 2010

In a long-term experiment, Salmonella heidelberg was found capable of significantly altering the 13C/12C, and 34S/32S abundance ratios during anaerobic SO3= reduction in Trypticase soy broth medium. During the experiment, the 13C/12C ratio of the product CO2 fluctuated by nearly 5%. The 32SO3= species was reduced faster than 34SO3= by a factor which varied from 1.026 near the beginning of the experiment to 1.042 near the end of it. This factor is significantly higher than that realized in the equivalent inorganic reduction.
A purple-pigment-producing bean wilt bacterium, Corynebacterium flaccumfaciens var. violaceum, n. var.
Authors: Schuster M. L. , Vidaver Anne K. , Mandel M.
Published: February 2010

A phytopathogenic coryneform bacterium was shown to be similar to Corynebacterium flaccumfaciens (yellow wilt) and C. flaccumfaciens var. aurantiacum (orange wilt). The newly described bacterium is provisionally given the nomen Corynebacterium flaccumfaciens var. violaceum n. var. The variety name indicates the extracellular purple pigment, the chief distinguishing characteristic of the organism. The optimal temperature for purple pigment production is 20 C in vitro, whereas infected seed turn purple over a wide range of temperatures. Media requirements were determined for optimal purple pigment production. The DNA base composition as moles % guanine + cytosine (GC), is 70.9 ± 0.8, for C. flaccumfaciens Nebr. 21, C. flaccumfaciens ATCC 6887, C. flaccumfaciens var. aurantiacum 2A, and C. flaccumfaciens var. violaceum CV8. The GC content is greater than that reported for other Corynebacterium species. The current taxonomic status of Corynebacterium and related genera is discussed.
Indolelactate dehydrogenase from Clostridium sporogenes
Authors: Jean Marcel , DeMoss R. D.
Published: February 2010

Indolelactate dehydrogenase has been purified 13-fold from cell-free extracts of Clostridium sporogenes. The enzyme is inactive with lactate, but active with indolelactate, phenyllactate, and p-hydroxyphenyllactate, and utilizes nicotinamide adenine dinucleotide (NAD) but not nicotinamide adenine dinucleotide phosphate NADP (1), as coenzyme. The reaction is reversible; the equilibrium constant is 6.3 × 10−6 M at pH 7.0, expressed as [indolepyruvate] [NADH] [H+]/[indolelactate] [NAD].The enzyme preparation exhibits regular Michaelis–Menten kinetics with respect to indolelactate, NAD, and NADP, but not with respect to indolepyruvate.
Studies on the pathogenicity of Candida albicans isolated from baboon
Authors: Al-Doory Yousef
Published: February 2010

The pathogenicity and mortality rate of Candida albicans from various sites of the baboon were studied in mice. Tissue population and pathogenicity of four selected isolates of this group were compared to two isolates of human origin. Ninety-one percent and 100% of mice were found to be infected by use of the intraperitoneal and intravenous routes respectively. No significant variations were found among the strains of baboon and human origin. The kidney was found to be the most susceptible organ, followed by the brain. The greatest total count of C. albicans from kidney tissue occurred in 96 hours and from other organs in 6–24 hours. A hypothesis relating to kidney susceptibility to C. albicans infection was introduced.
Serological differentiation of the Ascochyta species on peas
Authors: Madhosingh C. , Wallen V. R.
Published: February 2010

Specific immune serum against Ascochyta pisi was developed and three species-specific reactions were obtained by standard absorption techniques using extracts of both Ascochyta pinodella and Ascochyta pinodes. Ouchterlony tests showed a complex pattern of precipitation reactions in agar gel between the antigens from the three species and antisera developed in response to them and indicated distinct serological relationships among the three fungi. The pattern of reciprocal precipitin reactions indicates a closer serological relationship between A. pinodella and A. pinodes than between either of these two species and A. pisi. Two serologically similar antigenic components were present in the extracts from the three species.
Exigences en sels minéraux de Corynebacterium sepedonicum (Spiek. & Kott.) Skapt. & Burkh.
Authors: Bordeleau Lucien M. , Lachance Robert-A.
Published: February 2010

The mineral requirements of Corynebacterium sepedonicum (Spiek. & Kott.) Skapt. & Burkh., were studied in a medium containing seven amino acids, three vitamins, dextrose, and tris buffer. The organism does not grow in a mineral-free medium. Potassium phosphate monobasic and potassium phosphate dibasic are required in concentrations of 1.2 × 10−3 and 2.8 × 10−3 mole per liter respectively. Ammonium phosphate monobasic inhibits the growth. Potassium can be replaced by calcium when H3PO4 is used as a source of PO4---. Magnesium as MgCl2∙6H2O in concentration of 2 × 10−3 mole per liter is required for good growth but does not affect the morphology of the organism as reported for other bacteria. Manganese as MnSO4>∙H2O and iron as Fe(SO4)2(NH4)2∙6H2O, in concentrations of 10−3 and 10−6 mole per liter respectively, are not essential but stimulate the growth when added to potassium phosphate (KH2PO4 and K2HPO4) and magnesium. Copper, nickel, cobalt, aluminum, and zinc were found to be inhibitory.
Effets des purines et des pyrimidines sur la croissance de Corynebacterium sepedonicum (Spiek. & Kott.) Skapt. & Burkh.
Authors: Bordeleau Lucien M. , Lachance Robert-A.
Published: February 2010

The effects of purines and pyrimidines on the growth of Corynebacterium sepedonicum were studied in a synthetic medium containing amino acids, vitamins, mineral salts, and glucose. Among four purines tested, only adenine inhibited the growth of the organism. Hypoxanthine and guanine reversed the inhibition caused by adenine. None of four pyrimidines tested affected the growth. In the presence of pyrimidines, only hypoxanthine reversed the inhibition caused by adenine. It appears that purines and pyrimidines do not stimulate the growth of C. sepedonicum and that the synthesis of nucleic acids from these bases is not a limiting factor in the growth of the organism.
A chemical method for culture purification
Authors: Elliott L. F. , Spangler W. J.
Published: February 2010

A culture purification method that succeeded when streak methods had failed is described.
The calculated nitrogen requirements of a single cell of Escherichia coli
Authors: Hunt D. E. , Pittillo R. F.
Published: February 2010

A chemically defined broth medium, deficient in a growth-limiting nitrogen source, was used in a series of experiments which alllowed the calculation of the relative number of ammonium chloride molecules (approximately 1.0 × 109) required for one division cycle of a single cell of Escherichia coli.
Composition of DNA from Phytophthora infestans
Authors: Clark M. C. , Lawrence C. H. , Page O. T. , Hodgson W. A.
Published: February 2010

Deoxyribonucleic acid was extracted from the late blight fungus, Phytophthora infestans, and partially characterized in terms of its physical and chemical properties. Hydrolysis of the purified DNA followed by electrophoretic analysis failed to demonstrate the presence of constituents other than those characteristically found in DNA. Analysis of the nucleotide composition based on thermal denaturation studies yielded values for the percentage guanine–cytosine which are consistent with those reported for other members of the Phycomycetes.
Epiphytic microflora: the balloon print isolation technique
Authors: Rusch Volker , Leben Curt
Published: February 2010

A plant part is pressed on a sterile rubber balloon, which is inflated and then pressed on hardened agar in large plates.
Utilization of fructose and glutamate by Rhodospirillum rubrum
Authors: Gibson Margaret S. , Wang Chih H.
Published: February 2010

Fructose served as sole carbon source for the growth of Rhodospirillum rubrum anaerobically under light or aerobically in the dark while glucose did not. Glucose was not utilized by the organism at all. Radiorespirometric studies, using 14C specifically labelled fructose as substrate, revealed that fructose is catabolized exclusively via the Embden–Meyerhof–Parnas (EMP) glycolytic pathway. Both L-glutamic and D-glutamic acids can be utilized by this organism, via the tricarboxylic acid cycle (TCA) pathway, under either aerobic-dark or anaerobic-light conditions.