bluuebunny/crossref_metadata_2025 huggingface dataset:
Photodynamische Wirkung von Quinacrin auf Bakterien
Authors: Jacob H.‐E.
Published: July 2010

The acridine dye quinacrine (QA) was tested with regard to the photodynamic action on bacteria (Proteus mirabilis, Escherichia coli). The absorption maximum of the yellow dye QA ist in contrary to the photodynamically active dyes methylene blue (MB) an thiopyronine (TP) situated in the short wave region of the visible spectrum. Using for illumination a common light source – they have in general a weak emission in the short wave region – relatively high concentrations of QA are necessary for photodynamic action, and the difference between photodynamic inactivation and toxic effect is small. Using the light source XBO 500 with nearly equal emission in the range from 400 to 700 nm, a distinct photodynamic action of QA results. Comparing the photodynamic action of QA with those of MB and TP, QA has a low photodynamic effect, and the kinetics of inactivation of bacteria with QA is completely different from those obtained with the dyes MB and TP.
Regulative influence ofo‐aminobenzoic acid on the biosynthesis of nourseothricin in cultures ofStreptomyces nourseiJA 3890b IV. Bistability of metabolism and the mechanism of action of aminobenzoic acids
Authors: Gräfe U. , Bocker H. , Thrum H.
Published: July 2010

Using the semi‐continuous cultivation technique we could establish that specifically inStreptomyces nourseiJA 3890b during growth on a medium supplied with D,L‐alanine, NH4+, and maize starch there are two different phenotypes of the organism and stationary states of metabolism, respectively.

The expression of either the metabolic state 1 with an enhanced capacity to oxidative deamination of alanine via the NAD+‐dependent alanine dehydrogenase or the metabolic state 2 which may be characterized by the preferred use of ammonium ions via the NADP+‐dependent glutamate dehydrogenase was shown to depend strongly on the conditions of inoculum cultivation.

When the amino acid permeases were derepressed by cultivating the inoculum cells on amino acid media. probably due to the defective mechanism of negative feedback control of amino acid influx in this strain an abnormously high uptake of alanine was observed that, consequently, was correlated to the enhanced oxidation of this amino acid as well as to the intensive production of ammonia within the cell. This overproduction of cellular NH4+seems to bring about the subsequent repression of biosynthetic glutamate dehydrogenase and so on the accumulation of ammonia autocatalytically may rise up (metabolic state 1).

On the other hand, if the influx of alanine was kept low and the NADH oxidation was less efficient, respectively, or when there was high cellular activity of glutamate dehydrogenase the level of ammonia never did exceed the repressory limit and, accordingly, the expression of the metabolic state 2 was observed.

Switching‐over of metabolic flux from the state 2 towards the state 1 can be brought about either by increasing the level of nitrogen sources in the medium or by adding buffers pH > 7.5. In contrast, decrease of cellular level of NH4+was shown to induce the transition of metabolic state 1 into the state 2. This can be achieved not only by limitation of nitrogen source but also by adding different aminobenzoic acids and, alternatively, effectors of membrane function (short‐chain alcohols). inhibitors of cytochrome oxidases (sodium azide, potassium cyanide), heavy metal (Fe++)‐ chelating agents (catechol, 2.2′‐dipyridyl,o‐phenanthroline). ß‐alanine, and buffers pH < 7. This suggests that these effectors are capable of preventing the abnormously high influx of amino acids as well as its wasteful catabolism within the cell ofS. nourseiJA 3890 b.

Therefore. it seems likely that by this way the aminobenzoic acids and similar effectors can diminish the catabolite repression or inhibition of secondary metabolism by cellular excess of some nitrogen compounds in good agreement with its well‐known stimulatory action on the biosynthesis of the antibiotic nourseothricin in this strain.
Regulation of Neurospora crassa nucleosidases by some environmental factors
Authors: Mattoo A. K. , Dandekar A. M. , Trivedi J. P. , Majmudar G. H. , Patel D. M.
Published: July 2010

Enzymic cleavage of N‐glycosidic bonds of AMP, GMP, and inosine by the cell‐free extracts of Neurospora crassa has been studied. The enzymic activities with these substrates appear to be discrete from one another. The levels of these enzymes in the cell vary with age, and are dependent upon the inoculum size, aeration rate, and phosphate level in the medium. Glucose (or ribose) controls the phosphate‐mediated repression of all the three nucleosidases of this fungus.
Verlauf und Beeinflussung der Autolyse von Hypomyces ochraceus m 359
Authors: Riemay K.‐H. , Weise M.
Published: July 2010

Growth and natural autolysis of the ascomycete Hypomyces ochraceus were investigated in shake cultures by measuring dry weight, pH value, and uptake of carbohydrate. The alkaline autolysis resulted in maximum loss of 53% of dry weight during an incubation period of 35 days. Early autolysis was induced by limitation of oxygen, increasing temperature, addition of peracetic acid, and sodiumacide. Autolysis is discussed to be derived from deficiency of energy.
Ultracytochemical charactrization of non‐specific acid phosphatase activities in Saccharomyces cerevisiae
Authors: Böhm K. J. , Unger E.
Published: July 2010

Glutaraldehyde prefixation causes a considerable inactivation of the acid phosphatase of yeast protoplasts in dependence on the duration of aldehyde influence. Lead ions necessary for ultracytochemical demonstration effect a still stronger inhibition of enzymatic activity. Prefixation, however, protects the enzyme from further inhibition by lead.

At pH 4.4 in intact cells acid phosphatase activities are mainly localized in the periplasmic space and in vesicles fused with the plasma membrane. The cell wall and cytoplasm usually remain free of reaction products. On the cell surface activities are found in form of globular lead deposits. At pH 5.2 and 6.3 the periplasmic activity appears decreased compared to that at lower pH values and the intracellular activity is increased.

The plasma membrane of protoplasts is completely free of precipitates. The intracellular activity sites of protoplasts (cisternae of endoplasmic reticulum and/or Golgi‐like system, small vesicles, central vacuole, nuclear envelope) are the same as for intact cells.

The occurrence of at least two forms of acid phosphatase in S. cerevisiae is deduced.
Effects of drugs that influence eucaryotic motile processes on motility of Cystobacter fuscus (Myxobacterales)
Authors: Heumann H.‐G. , Kühlwein H.
Published: July 2010

Cytochalasin B, dbcAMP and EGTA were found to inhibit the motility of Cystobacter fuscus completely whereas colchicine and cAMP only reduced velocity of movement.
Factors influencing the copy number of F‐like plasmids in Escherichia coli and Salmonella typhimurium
Authors: Pritchard J. J. , Lemoine V. Rodriguez , Rowbury R. J.
Published: July 2010

The copy numbers of Flac, four F‐like plasmids and pLT2 were estimated in two strains of Salmonella typhimurium and (for all except pLT2) one strain of Escherichia coli. For organisms grown in casamino acids minimal medium, the plasmids spanned a 7–8 fold range of copy number with ColB‐K98 having the highest copy number in each strain and R124 the lowest. The copy number of ColB‐K98 was substantially greater than 1 in each of the strains tested. There was no clear relation between the plasmid size and copy number, although the plasmids studied spanned only a narrow size range. The copy number of individual plasmids was slightly reduced or not affected at all by the presence of a second plasmid in the same strain. Derivatives harbouring each of the plasmids were grown in three different media to ascertain how plasmid copy number responds to changes in growth rate. For each plasmid, the copy number increased with decreasing growth rate. Extracts from each of the three strains harbouring ColB‐K98 contained two distinct plasmid species. One appeared to be about twice as large as the other and both were absent from Col− segregants.
Biochemical studies on sporulation in blue‐green algae I. Glycogen accumulation
Authors: Sarma T. A. , Kanta Swarn
Published: July 2010

Glycogen accumulation in vegetative cells of Anabaena sp. is demonstrated to be a light‐dependent process. No glycogen accumulation is found in dark or in cultures supplemented with 10−5 M DCMU in light. Large quantities of glycogen acccumulate in cells undergoing sporulation and the amount increased with the onset of maturation of spores.
Effect of temperature on the transcription by bacteriophage T3‐induced RNA polymerase
Authors: Mann W. , Musielski H. , Laue R. , Michel S.
Published: July 2010

Bacteriophage T3‐induced RNA polymerase is rapidly inactivated at 42°C. Addition of T3 DNA delays this process for 30 s and reduces the rate with which the enzyme activity is lsot indicating that a labile binary complex between T3 DNA and polymerase must have been formed. The ternary complex between T3‐specific RNA polymerase, T3 DNA, and nascent RNA chains obtained when the enzyme is incubated with T3 DNA, GTP, ATP, and UTP is stable to heat (42°C) and only slowly inactivated by polyvinyl sulfate. The optimal temperature for the formation of polyanionresistant ternary complexes is 30°C while the elongation of T3 RNA chains proceeds fastest at 38°C.
Steroidumwandelnde Enzyme aus Mikroorganismen XII. Merkmale der Induktion der 4‐En‐3‐oxosteroid: (Akzeptor)‐l‐en‐oxidoreduktase in Nocardia opaca
Authors: Hörhold C. , Hüller E. , Rose G.
Published: July 2010

17α‐Methyltestosterone and the corresponding 1(2)‐dehydrocompound (Dianabol) are efficient inducers of the 4‐en‐3‐oxosteroid: (acceptor)‐l‐en‐oxidoreductase from Nocardia opaca. After a lag period of 4 hours the enzyme activity increases rapidly. During the induction the steroids are completely metabolized causing a drastical drop of specific enzyme activity. Using a fixed induction time the optimal steroid concentration and the temperature characteristic were found out. The influence of the concentration of the steroid water suspension on the induction effect is discussed to be dependent on the velocity of the dissolving of the steroid particles.

Chloramphenicol and streptomycin are powerful inhibitors of the induction process.
Reduktion von L‐Carnitin zu γ‐Butyrobetain durch Escherichia coli
Authors: Seim H. , Kleber H.‐P. , Strack E.
Published: July 2010

Der Stoffwechsel des L(–)‐Carnitins wurde an einem aus Rattendarm isolierten Stamm von Escherichia coli und an E. coli K12 unter aeroben und anaeroben Bedingungen im Hinblick auf die Entstehung von L‐Carnitinmangel untersucht.

Unter aeroben Wachstumsbedingungen unterlag das L‐Carnitinmolekül keinerlei Veränderungen. Auch unter anaeroben Bedingungen war L‐Carnitin nicht C‐ oder N‐Quelle, aber beide E. coli‐Stämme reduzierten L‐Carnitin zu γ‐Butyrobetain. Als weiterer Carnitinmetabolit wurde Crotonsäurebetain, nicht aber Trimethylamin, nachgewiesen. Die Bildung von γ‐Butyrobetain und Crotonsäurebetain war von der Art des Nährmediums und von der eingesetzten L‐Carnitinkonzentration abhängig und unterschied sich signifikant bei beiden E. coli‐Stämmen. Die L‐Carnitinreduktion wurde sowohl durch Elektronenakzeptoren der anaeroben Atmung, wie Nitrat und Trimethylamin‐N‐oxid, als auch durch Glucose und ein L‐Aminosäuregemisch, nicht aber durch Lactat und Succinat, gehemmt.
Cell wall regeneration of Candida spec. protoplasts
Authors: Popov E. , Reuter G. , Meyer H. W.
Published: July 2010

A yeast of the genus Candida which is able to grow on n‐alkanes was characterized by biochemical investigations: Crabtree effect, inhibition of ammonium utilization by asparagine, changes in the concentration of polysaccharides mainly concentrated in the cell wall. The yeast was compared biochemically and electron‐microscopically with its pure protoplast population, and the regeneration of the cell wall was studied. In correspondence with the asynchronously developing accumulation of glucan and mannan, electron microscopical studies have first only revealed glucan fibrils. Matrix formation (mannan) occurs only in the second stage of regeneration. After a regeneration period of 9 hours, the polysaccharides in the former protoplast population reached the concentration of the period before enzymatic removal of the cell wall. A tube‐like structure observed by light microscopy during the early stages of regeneration is shown electron‐microscopically to consist of a fibrillar network without matrix. Between newly formed cell wall and plasma membrane, in some cells groups of large flat vesicles were found, whose fracture faces are free of particles. After protoplast formation the invaginations of the plasma membrane arrange themselves in rows one behind the other. These findings are supported by further evidence suggesting that the invaginations are structures on the basis of lipid domains.
Carbon and nitrogen nutrition of plant pathogenic fungi associated with basal stem rots of cowpeas, Vigna unguiculata (L) WALP in Nigeria
Authors: Oladiran A. O. , Oso B. A.
Published: July 2010

Pythium aphanidermatum, Rhizoctonia bataticola (syn. = Macrophomina phaseolina), Botryodiplodia theobromae, and two strains of Selerotium rolfsii readily utilized for growth the monosaccharides glucose, fructose and mannose, the disaccharides sucrose and maltose and the polysaccharides dextrin and starch. In addition, S. rolfsii grew appreciably well on carboxymethylcellulose (CMC). When filter paper (nature cellulose) was supplied as sole carbon source, it was decomposed by B. theobromae, S. rolfsii (SR2) and R. bataticola.

In studies on nitrogen utilization, B. theobromae grew best on glutamic acid, P. aphanidermatum on glycine and the two strains of S. rolfsii on ammonium nitrate. R. bataticola utilized casein hydrolysate most effectively for growth. EDTANa2 was a poor nitrogen source for all the pathogens.
Dihydroxyacetone kinase of methanol‐assimilating yeasts. I. Regulation of dihydroxyacetone kinase from Candida methylica in situ
Authors: Hofmann K. H. , Babel W.
Published: July 2010

In order to investigate the control behaviour of dihydroxyacetone kinase of methanol‐grown Candida methylica under nearly physiological conditions kinetic and regulatory studies were carried out in situ. Yeast cells were made permeable to substrate and reaction products by treatment with Triton X‐100. Normal Michaelis‐Menten kinetics resulted in dependence upon the dihydroxyacetone concentration, both at the pH optimum of 7.6 and near the physiological pH‐value of 6.5. The Km obtained for dihydroxyacetone was 0.02 mm, independent of the pH‐value. The plots of dihydroxyacetone kinase activity as a function of the ATP concentration revealed complex kinetic characteristics with plateau regions. The maximum reaction rate was reached only after a lag time both at pH 7.6 and concentrations of ATP higher than 5 mm and at pH 6.5 and concentrations of ATP higher than 1.25 mm. Among a great number of tested metabolites no inhibitors of dihydroxyacetone kinase were found. Dihydroxyacetone kinase activity depending upon energy charge according to Atkinson exhibited curves of the U‐type. These results and further data concerning the regulation of other enzymes obtained with C. methylica and other yeasts were the basis to propose a preliminary overall model of fine control of the carbon and energy metabolism of methanol‐utilizing yeasts.
Bistability in a model of microbial product formation
Authors: Guthke R. , Knorre W. A.
Published: July 2010

A mathematical model of continuous growth of microorganisms and product formation with growth inhibition by the product is presented and investigated. Two stable steady states occur due to the competition of growth and product formation for the same limiting substrate. One stable state is characterized by a high product concentration but low biomass concentration whereas the other state is characterized by the opposite relations. The first steady state is approached by oscillating kinetics. Both phenomena are consistent with frequently observed kinetic instabilities in industrial fermentation processes.
Hyphomicrobium as a component of the aquatic microflora — morphological and physiological studies on two strains
Authors: Moaledj K.
Published: July 2010

Aspects of the morphology, metabolism and physiology of two oligocarbophilic strains of Hyphomicrobium (H4K and S5K), isolated from the Plußsee, were studied. Both strains are able to grow on mineral salts media without added organic carbon sources. Strain H4K grows well even in double distilled water. The two strains cannot grow on mineral media in the absence of atmospheric CO2. No growth occurred also in air purified of organic carbon, in spite of the presence of CO2. On the contrary, there is good growth in the presence of some organic compounds and without atmospheric CO2, i.e., heterotrophic metabolism without CO2 assimilation is possible. Growth was enhanced in a methanol atmosphere, and by the addition of yeast extract, methylamine, peptone and glucose. In nutrient solutions containing acetate or formate as carbon source, growth of H4K begins only after an adaptation period of ca. 4 weeks.
Naphthochinon‐Antibiotica aus Streptomyces lateritius. I. Fermentation, Isolierung und Charakterisierung der Granatomycine A, C und D
Authors: Fleck W. F. , Strauss D. G. , Prauser H. , Fleck W. F.
Published: July 2010

The fermentation and isolation procedures of the antibiotic granatomycin produced by Streptomyces lateritius are described. Furthermore, the producing strain ZIMET 43627 and the main constituents of granatomycin will be characterized. Granatomycin is a red‐violet pigment antibiotic of the naphthoquinone type. The physicochemical properties of granatomycin resemble those of granaticin. The antibiotic can be isolated from culture filtrates and from the mycelium by extraction with lower aliphatic alcohols. It can be purified by gel filtration methods. Granatomycin displays antimicrobial activity, particularly against grampositive and gramnegative bacteria, and antiviral activity against fowl‐plaque‐virus in mammalian cells. Granatomycin is useful in selection of resistant mutants of bacteria and viruses with decreased virulence but high immunogenity suitable for use as life vaccines against infection diseases. The physicochemical properties of the main constituents of granatomycin studied confirm the identity of granatomycin C with granaticin and the identity of granatomycin D with dihydrogranaticin. Granatomycin A is identical with the well‐known semisynthetic methylester of dihydrogranaticin. Therefore, the production of granatomycin A is the first possibility to produce this derivative of granaticin biosynthetically.
Kupfer‐II‐komplexe N‐heterocyclischer Formylisothiosemicarbazone mit antimikrobieller und β‐Lactamasen inhibierender Wirkung
Authors: Heinisch L. , Fleck W. F. , Jacob H.‐E.
Published: July 2010

The synthesis of copper(II)‐complexes from quinoline‐2‐ or quinoxaline‐2‐aldehyde‐isothiose‐micarbazones in pyridine and the elucidation of their structure are described. Some of the new substances exhibit an inhibitory action on growth of grampositive bacteria, especially Bacillus subtilis (ATCC 6633), furthermore in vitro the β‐lactamase I action is inhibited. Using penicillin‐resistant Staphylococci as test strains a strong penicillin‐synergistic action was discovered.
Degradation of steroids by microorganisms. XVIII. The reversibility of steroid‐l‐dehydrogenation during microbial side chain degradation of sterols by Nocardia
Authors: Komel R. , Groh H. , Hörhold C.
Published: July 2010

The aerobic side chain degradation of sterols often leads to mixtures of 1,4‐diene and 4‐ene compounds. By an additional anaerobic step a practically complete reverse reaction of the steroid‐1‐dehydrogenation occurs yielding only the corresponding 4‐ene compound.
Biochemical studies on sporulation in blue‐green algae. III. Effect of amino acids on glycogen accumulation
Authors: Sarma T. A. , Kanta Swarn
Published: July 2010

The effect of 21 amino acids was studied on glycogen accumulation during sporulation in the blue‐green alga Anabaena sp. All the amino acids enhanced the initial level of glycogen on the 4th day. The maximum amount of glycogen, on the 20th day, was noticed from l‐methionine, l‐tyrosine, glycine, and l‐histidine supplemented cultures. Others like l‐serine, l‐valine, l‐asparagine, dl‐alanine, l‐glutamic acid, l‐phenylalanine, l‐aspartic acid, l‐arginine, and dl‐lysine come next in the order. On the other hand, l‐cysteine and l‐cystine, although upto the 16th day they exhibited higher values of glycogen, did not show much variation in glycogen content over nitrogen‐free medium. Except in these two amino acids, in all others initiation of sporulation occurred on the 4th day, resulting in free spores on the 8th day. But in case of l‐serine, l‐asparagine, l‐isoleucine, and l‐phenylalanine free spores were noticed only on the 12th day while in dl‐lysine they were seen on the 16th day. l‐cysteine and l‐cystine supplemented media showed free spores on the 20th day as in nitrogen‐free control.
Bakterium MB 58, ein methylotrophes „Essigsäurebakterium”︁
Authors: Steudel A. , Miethe D. , Babel W.
Published: July 2010

Das stäbchenförmige, gram‐negative und Katalase‐positive Bakterium MB 58 ist fakultativ methylotroph. Es unterscheidet sich z. B. von Acetobacter suboxydans ATCC 621 H, das ebenfalls Methanol assimilieren kann (Hexulosephosphat‐Weg), kaum, weder in der Fähigkeit zur Oxydation verschiedener Substrate (Methanol, Äthanol, Glucose, Acetaldehyd u. a.) noch in den Cytochromprofilen oder im Enzym‐Muster nach Wachstum auf Methanol bzw. Glucose.

Beim Wachstum auf Glucose zeigt Bakterium MB 58 wie Gluconobacter oxydans diauxisches Verhalten, was darauf zurückgeführt wird, daß Glucose assimiliert und ein Teil davon gleichzeitig zu Gluconsäure oxydiert wird.

Außerdem können Phagen von Bakterium MB 58 verschiedene Acetobacter‐ und Gluconobacter‐Species lysieren, und auch mit Hilfe der Immunofluoreszenz sowie der Objektträgeragglutination läßt sich Bakterium MB 58 von den genannten „Essigsäurebakterien”︁ nicht unterscheiden.

Auf Grund dieser Befunde, die auf enge verwandtschaftliche Beziehungen hinweisen, wird vorgeschlagen, Bakterium MB 58 in die Gruppe der „Essigsäurebakterien”︁ einzuordnen.
Geomikrobiologische Untersuchungen XIV. Schwermetall‐Toleranz desulfurizierender Bakterien unter verschiedenen ökologischen Bedingungen
Authors: Brecklinghaus J. , Schwartz W. , Näveke R.
Published: July 2010

Tolerance and adaptation to heavy metals of Desulfovibrio‐ and Desulfotomaculum‐strains of different origin have been investigated in enrichment cultures under different conditions of sulphate supply. Three groups of low, medium, and high toxicity were found with As, V, and Mo in the first, Ni, Sb, Co, and Hg in the second, and Cd, Zn, U, and Cu in the third group. If the SO4″‐supply was restricted to heavy metal sulphates with a relation of 1:1 of heavy metal‐ and SO4″‐ions (2:3 with Sb2(SO4)3) the tolerance was somewhat lowered. Adaptation to higher concentrations of heavy metals was possible, if the strains had not yet been exposed and adapted to higher concentration levels at their natural habitats. The tolerance range of desulfurizers has been compared with the tolerance range of different biochemical types of microorganisms.
Inhibitor studies of phage T4 wild‐type and mutant DNA polymerases V. A summary of kinetic and inhibition data
Authors: Schroeder Cornella , Jantschak J.
Published: July 2010

The DNA polymerases of phage T4 wild‐type, the mutator mutant L98 and the antimutator mutant CB121 were purified about 100‐fold free of foreign enzyme activities interfering with the polymerase assay. The enzymes were characterized as to thermostability, exonuclease activity and kinetic data with DNA template primer, deoxythymidine 5′‐triphosphate, and a mixture of all four deoxynucleoside 5′‐triphosphates. The effects of eight inhibitors of DNA synthesis on the three enzymes were determined (Schroeder and Jantschak 1978 and 1980, Jantschak and Schroeder 1980) and are compared here. The most selective inhibitor, pyridoxal 5′‐phosphate, interacts with the active site of the polymerases while the two least discriminating drugs, distamycin A and actinomycin D, do not directly interact with the polymerases at all. The study was intended to test whether specific enzyme inhibitors elicit a differential response in temperature‐sensitive structural variants of this enzyme and whether, in principle, structural variants of virus enzymes or the respective ts‐ mutants in vivo are suitable as a screening system for selective antiviral agents.
Dihydroxyacetone kinase of methanol‐assimilating yeasts II. Partial purification and some properties of dihydroxyacetone kinase from Candida methylica
Authors: Hofmann K. H. , Babel W.
Published: July 2010

Dihydroxyacetone kinase (DHAK) from the cell‐free extract of methanol‐grown Candida methylica was partially purified about 100‐fold by a procedure employing streptomycine sulfate fractionation, ammonium sulfate fractionation, negative absorption on Cibacron blue F3G‐A sephadex G 200 and DEAE‐cellulose column chromatography. The enzyme was stable in 50 mm Tris‐HCl buffer pH 7.5 containing 60% glycerol at –18°C.

The pH optimum for the activity of DHAK from C. methylica was 7.5. The purified enzyme phosphorylated dihydroxyacetone four times faster than d,l‐glyceraldehyde. The apparent Michaelis‐Menten constants for dihydroxyacetone and d,l‐glyceraldehyde were 0.011 mm and 0.024 mm. Other C3 compounds including glycerol were not phosphorylated. ITP and UTP were used as phosphate donors with a reaction rate of 11% and 3.1%, respectively, in relation to ATP, whereas the reaction rates of DHAK from C. methylica with CTP or GTP were much lower than 1%. The reaction of DHAK depends upon the presence of divalent cations in the assay. The highest activity was found with Mg2+ ions. The reaction rates with Co2+ or Ca2+ ions were only 57.3% and 30.3%, respectively, in relation to the assay with magnesium ions. Manganese chloride in the assay led to a complete loss of activity.
Microbiological implications of electric field effects II. Inactivation of yeast cells and repair of their cell envelope
Authors: Jacob H.‐E. , Förster W. , Berg H.
Published: July 2010

The inactivation of yeast cells in different growth phases by an electric field pulse was investigated. Cells of Saccharomyces cerevisiae in the logarithmic growth phase were found to be much more sensitive with respect to an electric discharge than those in the stationary phase. The influence of the electric field pulse characteristics on the inactivation as well as possible secondary effects were studied. The polyene antibiotic perhydrohexafungin (PHF) is used as a tool to sense defects in the yeast cell envelope brought about by electric field action. The repair kinetics of these defects was followed after the impulse. At least two repair stages can be distinguished, a fast one in the second range and a slower one which takes place after plating the cells on a nutrient medium. The obtained results are discussed in connection with current theories of reversible dielectric breakdown in biological membrane systems.
Studies on air‐borne fungi at Qena I. Seasonal fluctuations
Authors: Moubasher A. H. , Abdel‐Fattah H. M. , Swelim M. A.
Published: July 2010

73 species which belong to 24 genera were collected in 200 and 35 esposures made during the period May 1976–October 1977 at each of two levels (2 m and 20 m).

The air‐borne fungi showed seasonal periodicities and the highest incidence was recovered in spring and autumn and the least in summer.

Aspergillus was the dominating genus. 17 species were collected at the two levels of which A. niger and A. flavus were the most common.

Other common genera were Cladosporium which was represented by C. herbarum, C. cladosporioides, C. sphaerospermum, and C. macrocarpum. 7 species of Curvularia were identified of which C. pallescens was the most frequent at the low and C. spicifera at the high level. Drechslera was represented by 6 species of which D. halodes was the most common at the two levels. Only one Alternaria species, A. alternata was isolated at both levels. 10 Penicillium were recovered, P. notatum was the most frequently one isolated at the two levels.

Many fungal spore showers of Cladosporium, Aspergillus, Curvularia, and Alternaria were recorded during the experimental period.
Light‐induced oscillations of the glutamate pool size and of the respiratory oxygen uptake in the blue‐green algaAnacystis nidulans
Authors: Metzler H.
Published: July 2010

The glutamate and glutamine pool contains about 75% of the free amino acids ofAnacystis nidulansharvested from a growing culture. Light pulses induced oscillations of the rate of oxygen uptake and of the size of the glutamate pool under certain physiological conditions. The frequencies of these oscillations were similar. During the oscillation the size of the glutamate pool was transiently reduced to about 50% of the dark level. The pool size of 2‐oxoglutarate did not show similar oscillations. A phase plane plot of the glutamate against the respiration oscillation supported a connection of both oscillations.
Microbial fixation of nitrogen in the presence of lanthanum sulphate
Authors: Ranganayaki S. , Bahadur K. , Mohan C.
Published: July 2010

The effect of lanthanum sulphate on five Azotobacter strains (4A7, 10, 5A2, 5A1, and 3A3) isolated from Allahabad soil consists in a considerable increase in the nitrogen fixation, carbon consumption and in the amount of nitrogen fixed in mg per g of carbon consumed. The presence of 200 μM, 300 μM and 400 μM lanthanum sulphate in culture media increases the fixation of nitrogen by all the nitrogen fixers significantly.
Response of a wild type and a non‐nitrogen‐fixing mutant of Anabaena doliolum towards different amino acids
Authors: Kumar Ashok , Kumar H. D.
Published: July 2010

The effects of various amino acids on growth and heterocyst differentiation have been studied on wild type and a heterocystous, non‐nitrogen‐fixing (het+ nif−) mutant of Anabaena doliolum. Glutamine, arginine and asparagine showed maximum stimulation of growth. Serine, proline and alanine elicited slight stimulation of growth of wild type but failed to show any stimulatory effect on mutant strain. Valine, glutamic acid, iso‐leucine and leucine at a concentration of as low as 0.1 mM were inhibitory to growth of parent type. Methionine, aspartic acid, threonine, cysteine, and tryptophan did not affect growth at concentrations lower than 0.5 mM. But at 1 mM, these amino acids were inhibitory. In addition to the stimulatory effects of glutamine, arginine and asparagine, the heterocyst frequency was also repressed by these amino acids. Glutamine and arginine at 2 mM completely repressed heterocyst differentiation in the mutant strain; however, other amino acids failed to repress the differentiation of heterocysts. Our results suggest that glutamine and arginine are utilized as nitrogen sources. This is strongly supported from the data of growth and heterocyst differentiation of mutant strain, where at least with glutamine there is good growth without heterocyst formation. Studies with glutamine and arginine on other N2‐fixing blue‐green lagae may reveal the regulation of the heterocyst‐nitrogenase sub‐system.
Regulation of ammonia assimilation in ammonia‐limited chemostat cultures of Escherichia coli ML 30: Evidence of bistability
Authors: Müller P. J. , von Frommannshausen Beate , Schütz H.
Published: July 2010

In a preceding paper evidence of two stationary stable states (bistability) in the specific activity of glutamine synthetase (GS) in ammonia‐limited steady‐state cultures of Escherichia coli ML 30 at dilution rates (D) about 0.15 h−1 was described (Müller et al. 1977). For better understanding of the regulation mechanisms leading to GS bistability chemostat experiments were performed over a wide range of dilution rates up to D = 0.8 h−1. For each steady state the specific activities of GS and glutamate dehydrogenase (GDH) – the other key enzyme of the two NH3 assimilation routes in E. coli – and in addition the remaining NH3 concentration in the culture liquid were determined.

Parallel to GS bistability two states of GDH activity and NH3 concentration are found. The higher state of GS is connected with a lower GDH activity and NH3 concentration. With rising D the GS activities decrease whereas GDH activities and NH3 concentrations increase.

Since no adenylation of the GS is detectable GS bistability seems to be regulated on the level of enzyme synthesis like GDH bistability.

From the experimental findings a mathematical model is derived based on the bottle neck enzyme theory of growth. It describes the dependence between the specific growth rates on the one hand and the specific enzyme activities and NH3 concentration on the other. It is shown that the specific uptake rate of the limiting NH3 and the specific growth rates, respectively, depend on the simultaneous action of two bottle neck enzymes which are connected by a regulative link.
A comparison of the toxic effects of 2‐deoxy‐D‐glucose and 2‐deoxy‐2‐fluoro‐D‐hexoses on Saccharomyces cerevisiae cells and protoplasts
Authors: Biely P. , Rjazanova L. P. , Tsiomenko A. B.
Published: July 2010

The toxicity to the cells and protoplasts of Saccharomyces cerevisiae of the sugar analogues modified at carbon 2 increases in the order 2‐deoxy‐D‐glucose (DG), 2‐deoxy‐2‐fluoro‐D‐glucose (FG) and 2‐deoxy‐2‐fluoro‐D‐mannose (FM). The fluorohexoses, similarly as DG, behave generally as analogues of both glucose and mannose, depending on the hexose used as a carbon source in the medium. Relative inhibitions of glucan and mannan synthesis in protoplasts were found to be dependent more on glucose and mannose used as the growth support than on the type of the sugar analogue. Certain degree of structural relationship of fluorohexoses to the corresponding natural hexoses was reflected in their effects on growth of intact cells. Growth on glucose was inhibited most effectively by FM, growth on mannose by FG. The data obtained support the view that the sugar analogues interfere mainly with the glucose‐mannose interconversion catalyzed by hexosephosphateisomerases. A comparison of the effects of fluorohexoses and DG on the synthesis of extracellular invertase and intracellular α‐glucosidase and alkaline phosphatase in protoplasts pointed to the fact that all three sugar analogues tested also participate in metabolic control of enzyme synthesis.
Regulation of steroid 16α‐hydroxylation in Streptomyces olivoviridis
Authors: Dlugoński J. , Sedlaczek L.
Published: July 2010

The steroid 16α‐hydroxylase of Streptomyces olivoviridis was shown to be constitutive, but synthetized only in small amounts in the absence of cortisol. The induction of the enzyme with the steroidal substrate resulted in a distinct increase in the 16α‐hydroxylation rate. This increase in activity, however, could be demonstrated only in later phases of culturing, after the growth of the mycelium was completed. The possible mechanisms controlling the activity of the enzyme during the growth phase of the culture are discussed.
Charakterisierung von Strukturelementen in den Lipopolysacchariden von Pasteurella multocida
Authors: Erlee W. , Feist H. , Flossmann K. D. , Jacob B. , Pilarski A.
Published: July 2010

In the main fraction of oligosaccharides obtained after the acetic acid hydrolysis of the lipopolysaccharides of the strain PM were identified: terminal bound glucose and L‐glycero‐D‐mannoheptose, 1,2‐,1,3,4‐, and 1,3,4,6,‐linked heptose. The oligosaccharide of the strain 1297 S contains terminal linked galactose, 1,4‐ or 1,6‐linked glucose and 1,4‐linked N‐acetylglucosamine additionally. The molar ratios of these elements show the heterogenicity of the preparations. The determined molecular weights underline the R‐character of the LPS

In the by‐fractions of the acetic acid hydrolysis the known mannan and another polysaccharide with galactose and glucosamine were identified.
Propionate formation in Rhodospirillum rubrum under anaerobic dark conditions
Authors: Voelskow H. , Schön G.
Published: July 2010

Experiments with 14C labelled propionyl‐CoA, methylmalonyl‐CoA and succinyl‐CoA showed that these compounds are intermediates of propionate synthesis in fermentative metabolism of Rhodospirillum rubrum. The rate of propionate and succinate production is dependent on the CO2 concentration of the medium. There is, however, no evidence for a transcarboxylation, and high concentrations of propionate in the medium did not inhibit propionate synthesis as is the case in propionibacteria. PEP‐carboxykinase (EC 4.1.1.32) and propionyl‐CoA‐carboxylase (EC 6.4.1.3) showed high activities, whereas the other two PEP‐carboxylases (EC 4.1.1.31, EC 4.1.1.38), and the pyruvate‐carboxylase (EC 4.1.1.1.) showed only very low activity. It is probable that in pyruvate fermentation metabolism of R. rubrum no specific enzymes are activated for propionate formation and all enzymes are still present from aerobic or phototrophic preculture.
Effect of sodium molybdate on microbial fixation of nitrogen
Authors: Ranganayaki S. , Mohan Chandra
Published: July 2010

The effect of 0, 100, 200, 300, 400, and 500 μM concentrations of sodium molybdate in the culture media of the five Azotobacter species isolated from Allahabad soil was studied. It was observed that the presence of molybdenum in the culture media of all the bacterial samples increased the fixation of nitrogen indicating that molybdenum is essential for increasing the efficiency of the nitrogen fixers for nitrogen fixation.
Optimierung von Kulturbedingungen für Acinetobacter calcoaceticus beim Wachstum auf n‐Alkanen in einem Laborfermentor
Authors: Fricke B. , Bergmann R. , Sorger H. , Aurich H.
Published: July 2010

The growth conditions for the cultivation of Acinetobacter calcoaceticus in a commercial laboratory fermenter have been optimized. This was done taking former results of shake cultures as a basis. At the end of the logarithmic phase up to 10 g/l dry weight were obtained.

The following culture conditions have been used: The medium contained 10 ml/l n‐alkane and 6 g/l NH4Cl. The pH was adjusted to 6.5 and pO2 employed to 70% saturation.

A 12 times higher amount of dry weight was observed compared with shake culture technique.
Transformation of 12‐deoxycardenolids with Streptomyces purpurascens
Authors: Albrecht K. , Máté G. , Láng T.
Published: July 2010

Streptomyces purpurascens transforms primary and secondary 12‐deoxycardenolids into digoxin, 7β‐hydroxy‐digitoxin and 7β‐hydroxy‐digoxin, respectively. A metabolic pathway is proposed for cardenolid transformations and the enzymes participating in it are investigated. The substrate concentration in the medium can be increased by using a water‐miscible solvent of electron donor character. The newly developed procedure yields 0.5 g/l−1 of digoxin in a five‐day fermentation.
Regulation der PEP‐Carboxylase des fakultativ methylotrophen Acetobacter sp. MB 58
Authors: Loffhagen N. , Babel W.
Published: July 2010

Acetobacter sp. MB 58 assimilates methanol via the fructose‐1,6‐bisphosphate variant of the hexulose phosphate pathway. Glyceraldehyde‐3‐phosphate originates as net product of an assimilation loop involving the regeneration of the C1‐acceptor ribulose‐5‐phosphate and must be available for the de novo synthesis of the C1‐acceptor as well as for the oxidative glycolysis.

It is made probable in a regulatory model that this is accomplished via alternating anabolic and catabolic phases which are controlled by concerted action of PEP‐carboxylase and pyruvate kinase. Whereas Ac‐CoA is a crucial effector and ä‐ketoglutarate and aspartate are inhibitors for the PEP‐carboxylase, the pyruvate kinase is assumed to be regulated by energy charge.
Charakterisierung eines CaCl2‐abhängigen Transfektionssystems von Escherichia coli und T3‐Phagen‐DNS
Authors: Stompe H. , Michel S. , Mann W. , Richter G.
Published: July 2010

Transfection by DNA isolated from bacteriophage T3 was studied using Escherichia coli 921/0 as host. The following conditions were found optimal:

Competent E. coli 921/0 were obtained by harvesting the bacteria at the onset of late exponential growth (5 × 108 cells/ml) and treating the latter with 0.05 M CaCl2. Hereafter, the microbes were suspended in 50 mM Tris‐HCl buffer (pH 7.2) and the concentration adjusted to 7 × 109 cells/ml. T3 DNA was added and the suspension kept at 0°C for 15 min. Determination of the number of infectious centers was then carried out in the usual way. The efficiency of transfection under these conditions amounted to 104 p. f. u./μg DNA.

Preincubation of competent bacteria with T4 DNA at 0°C before the addition of T3 DNA reduced the number of infectious centers. However, if T3‐ and T4 DNA were added simultaneously no decrease of the transfection efficiency occurred. Calf thymus DNA was without influence on transfection.
Aktivierung von Proteinbiosynthesen in auswachsenden Sporen von Bacillus subtilis
Authors: Wachlin G. , Hecker M.
Published: July 2010

The programme of protein synthesis as an indicator for the control of gene expression was examined during outgrowth of Bacillus subtilis spores. At various stages of outgrowth cells of Bacillus subtilis were labelled with 35S‐L‐methionine. Extracted proteins were separated on two‐dimensional gels according to O'FARRELL (1975). Three groups of proteins were synthesized during outgrowth:

During all stages of outgrowth a great number of “vegetative genes” is expressed. The programme of protein synthesis of the outgrowing cell is very similar to that of a vegetative cell.

Only a few proteins — probably the products of outgrowth‐genes — are synthesized especially in outgrowing spores and turned off at different stages of outgrowth.

The synthesis of a minor group of vegetative proteins is triggered during different stages of outgrowth.

In contrast to earlier assumptions (comp. TORRIANI and LEVINTHAL 1967, HANSEN et al. 1970, GALIZZI et al. 1976) we suggest that only a small portion of the genome is activated during outgrowth as a dependent sequence.

These results are discussed on the basis of earlier concepts about the regulation of outgrowth as a developmentally regulated gene expression programme.
Steroid modifications with immobilized biocatalysts — use of immobilized enzyme‐requiring cofactor regeneration and of immobilized mycelium
Authors: Ergan F. , Atrai P. , Dhulster P. , Gellf G. , Kim M. N. , Legoy M. D. , Thomas D.
Published: July 2010

Two biological approaches have been investigated for specific modifications of steroids. The first one uses the purified enzyme for the specific dehydrogenation of androsterone to androstanedione. The enzyme used is 3α‐hydroxysteroid dehydrogenase which requires a cofactor (NAD). A cofactor regeneration is needed so that the process could work continuously. The conjugation of two points (immobilization of the enzyme and optimization of the ratio methanol‐water) allows a continuous work of the enzyme during 25 days. Moreover, we propose a chemical regeneration of the cofactor using methoxy derivative of phenazine methosulphate. Right now it is the limiting step of the process.

The second approach of steroid modification uses a whole mycelium of Aspergillus phoenicis for the specific hydroxylation of progesterone to 11α‐hydroxy progesterone. The transformation of 90% of the progesterone is obtained with calcium alginate immobilization and the lowest number of products is obtained at pH lower than 2.5 with carrageenan and polyurethane immobilization.

It seems promising to apply immobilized biocatalysts to the bioconversion of hydrophobic compounds in organic solvents system.
Alteration of interaction with virulent bacteriophage Tal during differentiation of Thermoactinomyces vulgaris
Authors: Kretschmer Sigrid
Published: July 2010

During its life cycle Thermoactinomyces vulgaris 1227 and 1261 substrate mycelium showed three modes of interaction with the virulent phage Tal, each expressed at a distinct morphological stage. Primary mycelium arising from spores 50 min after start of germination was the only stage which propagated phages upon infection. However, infection of growing secondary mycelium or of late sporulation stages resulted in a loss of phage. The lack of phage production upon infection of growing secondary mycelium was not related to sporogenesis, since it appeared already 3.5 hours before the beginning of sporulation. If phages were added to the secondary mycelium at the beginning of spore formation, the phage genome became integrated in the developing spores in a heat‐stable state. Allowing outgrowth of these prophage‐carrier spores, phages were produced similarly as in germ tubes arising from normal spores infected at the time of inoculation.

The growing secondary substrate mycelium was characterized by competence for the uptake of exogenous DNA. Since at the stage of competence phages were neither produced nor was phage DNA trapped, the earlier reported lack of transfection in undisturbed differentiating T. vulgaris is now understandable.
Elektronenoptische Untersuchungen zur in vitro‐Wirkung von Dipyridamol auf das Pseudorabiesvirus
Authors: Zöpel P.
Published: July 2010

Dipyridamole at a concentration of 50 μM/ml displays no activity on adsorption and penetration of pseudorabies virus in chicken embryonal cells. Furthermore, first stages of virus replication take place within the nucleus, whereas incomplete virus cores defective in DNA content are found within the nucleoplasm at times when the regular viral replication has been finished in controls. Defective pseudorabies virus particles lacking in DNA‐content of the core, can be observed at the end of normal replication time. Consequently, the antiviral activity of dipyridamole may be due to blocking of the synthesis or of the incoporation of infectious viral DNA into the virus core.
Physiologischer und zellbiologische Charakterisierung des Proteasebildners Thermoactinomyces vulgaris während Langzeit‐Kultivation im Rührfermentor
Authors: Kretschmer S. , Körner D. , Strohbach G. , Klingenberg P. , Jacob H.‐E. , Gumpert J. , Ruttloff H.
Published: July 2010

The physiological behaviour of Thermoactinomyces vulgaris — producing a thermostabile serine‐protease — was analyzed during fermentation. During 38 h the consumption of nutrients and oxygen as wll as the rates of macromolecular and protease synthesis were measured. The morphological and ultrastructural changes of the mycelia were also studied.

The mycelia grew exponentially for about 5 hours. After a short lag and a second slower growth phase, growth continued about linearly until the end, as was indicated by a constant rate of incorporation of labelled thymidine. However, at the same time a changing portion of hyphae — up to 45% — underwent lysis. According to the changing ratio of growing and lysing material, regarding the physiological activity of the culture the fermentation process could be divided into 4 periods.

The formation of the protease started at the transition to the slow growth phase and continued linearly. The ability to produce the protease was attributed to a mycelium being formed after the shift down caused by limitation of supply of utilizable nitrogen compounds. The end of protease production 10 h later was correlated to a drastic decrease of the respiratory activity of the mycelia, probably caused by exhaustion of easily utilizable carbohydrates.