bluuebunny/crossref_metadata_2025 huggingface dataset:
Production, localization and glucose repression of β‐glucosidase in Trichoderma longibrachiatum
Authors: Sandhu D. K. , Sidhu M. S.
Published: February 2007

Optimal production of β‐glucosidase was obtained by incubating the culture at 27°C in a growth medium that had an initial pH of 5.0 and contained cellobiose. The bulk of the enzyme (70%) was present in a cell‐associated state (cell debris and cytosol) while only a small portion (30%) appeared in the culture filtrate. When cellulosic substrates were used, the major portion of the enzyme (70%) appeared in the extracellular fraction. A repression of the enzyme occurred in the presence of glucose. A drop of the pH of the medium during the exponential growth phase coincided with a rapid inactivation of the enzyme. The glucose effect was most likely mediated by adverse effects of low pH on the integrity of the enzyme.
Formation of enzyme‐bound L‐phenylalanine by a cell‐free system of Claviceps purpurea
Authors: Maier W. , Gröger D.
Published: February 2007

Ergotamine synthetase purified by ammonium sulfate precipitation, gel filtration and ion exchange chromatography on DEAE‐Sepharose CL‐6B binds l‐phenylalanine in an acid‐stable, apparently covalent, form. This substrate‐enzyme complex might be involved in ergopeptine synthesis.
Wechselwirkungen der Aldehyddehdyrogenase aus Acinetobacter calcoaceticus mit Membranlipiden II. Rekonstitution in künstlichen Membranvesikeln
Authors: Aurich H. , Bergmann R. , Lasch J. , Koelsch B. , Sorger H.
Published: February 2007

Purified aldehyde dehydrogenase (NADP+‐dependent) of intracytoplasmic membranes of Acinetobacter calcoaceticus could be incorporated from micelles formed during the purification procedure into liposomal membranes. Both the cholate dilution method and the ultrasonication method were suitable to produce enzyme liposomes. In unilamellar liposomes produced by phosphatidyl choline, the enzyme activity decreased to 1% (or less) of the original activity. In contrast, about 10% of the original activity could be preserved in unilamellar liposomes prepared from bacterial phospholipids.

The destruction of the enzyme liposomes induced by detergents (lauroyl sarcosinate) was followed by measuring the wavelength dependence of turbidity, which allowed us to draw conclusions on size and stability of the particles in the suspension. In addition these measurements demonstrated that decanal and NADP+ did not destroy the liposomal structure at concentrations necessary for the determination of enzyme activity.

The liposomal enzyme was inactivated to a lesser degree by proteinase K than the micellar enzyme. Both phospholipase A2 and D inactivated the enzyme incorporated into the liposomal membranes to about 50%. After treatment with phospholipase A2, the enzyme could be reactivated by bacterial phospholipids. After treatment with phospholipase D, no reactivation was possible by bacterial phospholipids.
Untersuchungen zum Glutamat/Aspartat‐Metabolismus von Candida maltosa
Authors: Casper P. , Bode R. , Samsonova I. A. , Birnbaum D.
Published: February 2007

Candida maltosa mutants deficient in the metabolism of glutamate aspartate were isolated. One of these mutants required asparagine, the second asparagine or aspartate, and the third grew with various amino acids (glutamate, glutamine, aspartate, asparagine, proline, arginine, ornithine, or lysine) or excess of ammonia. The biochemical defects were as follows: asparagine synthetase (asn1), aspartate aminotransferase (asp1), and glutamate synthase (glu1). On the basis of these data and additional biochemical studies we suggest that glutamate synthase is required for the assimilation of ammonia, and that glutamate dehydrogenase may be involved in glutamate production only in the presence of excess of ammonia. Aspartate is only synthesized from glutamate via transamination, while the synthesis of asparagine from aspartate is catalyzed by an asparagine synthetase.
Sporothrix nivea n. sp. — ein Methanol und Kohlenwasserstoffe verwertender Pilz
Authors: Kreisel H. , Schauer F.
Published: February 2007

Two fungal strains of the genus Sporothrix, isolated from industrial waste water, were characterized with respect to some morphological and physiological properties. After comparison with other species of the genus Sporothrix, the fungal strains are described as Sporothrix nivea, n. sp.

Among 28 carbon sources tested, such as sugars, polysaccharides, alcohols, organic acids, and hydrocarbons, 23 are utilized. The most remarkable property of Sporothrix nivea is the utilization of both n‐alkanes and methanol.
Uptake of nourseothricin by the producing microorganism, Streptomyces noursei
Authors: Röder B. , Gräfe U.
Published: February 2007

The uptake of 14C‐(U)‐nourseothricin by stationary phase mycelium of Streptomyces noursei JA 3890b‐NG 13/14 was demonstrated. An energy‐dependent transport system appears to be involved in the transport of the antibiotic. Relatively large quantities of the antibiotic were adsorbed to the surface of mycelium. Degradation of nourseothricin by the producing microorganism was not detectable.
Leukaemomycin‐geblockte Mutanten des Streptomyces griseus und ihre Pigmente III. 11‐Desoxydaunomycinonderivate aus der Mutante ZIMET 43699/G44
Authors: Wagner Christina , Eckardt K. , Tresselt D. , Ihn W. , Schumann G. , Fleck W. F.
Published: February 2007

The isolation and identification of several anthracyclinones (designated as G44‐K4/5, G44‐G1, G44‐G2) and anthracyclines (G44‐A, B, C, D, E, F, G) produced by the mutant strain IMET JA 3933/G44 of the daunomycin‐producing Streptomyces griseus strain IMET JA 3933 are described. G44‐K4/5 was found to be identical with 7,11‐dideoxy‐13‐dihydrodaunomycinone previously isolated from a mutant strain of Streptomyces coeruleorubidus. Compound G44‐G1 was identified as 11‐deoxydaunomycinone, the aglycone of the antibiotic 11‐deoxydaunomycin. G44‐G2 was found to be a stereoisomer of G44‐G1. The NMR and CD spectral data suggest strongly that the compound is 7‐epi‐11‐deoxydaunomycinone. Of the 7 isolated G44‐glycosides only the major component G44‐B could be identified. Comparison with an authentic sample revealed that this compound is 11‐deoxydaunomycin which had previously been isolated from cultures of Streptomyces peucetius var. aureus and Micromonospora peucetica. As reported for S. coeruleorubidus, S. peucetius var. aureus, and Micromonospora peucetica the 11‐deoxydaunomycinone derivatives described in this paper were isolated from the fermentation broth of a mutant of a daunomycin‐producing wild type strain. This suggests that in general the accumulation of 11‐deoxydaunomycinone derivatives may be the result of a block of C11‐hydroxylation in the normal biosynthetic pathway of daunomycin and its analogues.
Phage adsorption and productive lysis in stable protoplast type L‐forms of Bacillus subtilis and Streptomyces hygroscopicus
Authors: Gumpert J. , Zimmermann I. , Taubeneck U.
Published: February 2007

Transferable productive lysis in stable protoplast type L‐form cells of Bacillus subtilis was producted by 6 phages out of 14 strains virulent for the parent B. subtilis 170 and 1997. Most of these Phages lytie for L‐forms show the ϕ 29 morphology characteristic for the smallest B. subtilis Phages containing double‐stranded DNA. Among 31 actinophages, 23 of which were virulent for Streptomyces hygroscopicus, only SLE 109 and ϕc 31 gave productive infection of the stable protoplast type L‐form of S. hygroscopicus NG 33–354.

Electron microscopic investigation and treatment by DNAse demonstrated that infection of L‐forms cells is an adsorption‐injection process, and that it is not caused by transfection of free phage DNA or endocytotic uptake of phage particles. Because in both stable L‐forms cell wall biosyntheesis blocked irreversibly the results allow the conclusion that specific receptors must be localized in the cyroplasmic membrane for those phages producing transferable lysis in protoplast type L‐forms. Localization of receptors for certain phages in the cytoplasmic membrane seems to occur in many Gram‐positive bacteria, but not in Gram‐negative bacteria.
Effect of tryptophan on 2,4‐dichlorophenoxyacetic acid toxicity in the nitrogen‐fixing‐cyanobacterium Nostoc linckia
Authors: Mishra A. K. , Tiwari D. N.
Published: February 2007

The combined effect of a hormone weed killer 2,4‐dichlorophenoxyacetic acid (2,4‐D) and an amino acid (tryptophan) has been studied on growth and heterocyst differentiation in the cyanobacterium Nostoc linckia. 2.4‐D at 100 μg/ml stimulated growth and heterocyst frequency in combined nitrogen‐free medium while its higher concentrations inhibited both. Tryptophan under similar conditions promoted much growth yield with 3–4 fold enhanced heterocyst frequency than the control. Such heterocysts were immature and showed germination under in situ condition. The concentrations of 2,4‐D (100 μg/ml) and tryptophan (50 μg/ml), stimulatory to growth and heterocyst formation, caused additive effect while herbicide inhihibition of nitrogen‐fixing growth at higher doses was partially relieved by tryptophan but tryptophan‐induced heterocyst frequency was completely suppressed under this condition. The possible role of interaction of these two chemicals on growth and heterocyst formation has been discussed.
Catabolism of androst‐4‐ene‐3,17‐dione by mutant strains of Nacardia restricta
Authors: Miclo A. , Germain P. , Lefebvre G.
Published: February 2007

Different mutants of the catabolism of androst‐4‐ene‐3,17‐dione were produced in Nocardia restricta by action of γ‐rays and nitrosoguanidine. These selected mutants (acetate+‐androst‐4‐ene‐3,17‐dione−) are hexanoate−. Their behaviour is identical to the mutants selected as hexanoate− acetate+ which are themselves incapable of growing on androst‐4‐ene‐3,17‐dione. These mutants degrade androst‐4‐ene‐3,17 dione to methylperhydroindane dione propionic acid in presence of acetate with a molar yield of about 50%. The study of the biosynthesis of the 1,2‐steroid‐dehydrogenase in the mutant strains shows that a metabolite of MEPHIP is an inducer of the biosynthesis of this enzyme. On the other hand, the behaviour of these mutant strains shows an inductible β‐oxidation mechanism which takes place in the catabolism of methyl perhydroindane dione propionic acid. Another isolated mutant strain degrades androst‐4‐ene‐3,17‐dione with an transient accumulation of 3‐hydroxy‐9,10‐secoandrosta‐1,3,5(10)‐triene‐9,17‐dione.
Identification of Bacillus species from ‘iru’, a fermented African locust bean product
Authors: Odunfa S. A. , Oyewole O. B.
Published: February 2007

Thirty‐seven Bacillus isolates were obtained from fermenting locust bean (‘iru’) from three different locations in Nigeria. The isolates were characterized on the basis of biochemical and physiological tests. Thirty‐two of the isolates were identified as B. subtilis, two as B. pumilus and three as B. licheniformis.

The Bacillus species were sub‐divided into strains. Five different strains of B. subtilis and two of B. pumilus were identified. Biochemical tests showed that the strains differ in starch hydrolysis nitrate reduction and methyl red reaction and in their ability to produce acetylmethylcarbinol. They also vary in their patterns of sugar fermentation. This study shows that various strains or dossibly subspecies of B. subtilis are the major Bacillus species involved in the fermentation of the African locust bean (Parkia biglobosa).
DHBA (2,3‐Dihydroxybenzoesäure)‐Ausscheidung durch einen enterobactinnegativen multiresistenten Salmonella typhimurium‐Wildstamm
Authors: Rabsch W. , Paul P. , Reissbrodt R. , Rabsch W.
Published: February 2007

In investigations of iron siderophores produced by different Salmonella typhimurium strains we found a strain deficient in enterobactin production. Using microbiological and chemical methods, we detected the production and excretion of 2,3‐dihydrobenzoic acid, a metabolite of the enterobactin biosynthesis pathway. The strain was able to produce aerobactin. We suggest that the iron uptake of pathogenic strains can be mediated by aerobactin alone. For a correct enterobactin bioassay it is necessary to use a mutant unable to grow on 2,3‐dihydroxybenzoic acid.
Biochemical studies on Mycobacterium leprae
Authors: Prabhakaran K.
Published: February 2007

Very little information is available on the basic biology of Mycobacterium leprae. It is not known why the organism fails to grow in bacteriological media or in cell cultures and why it has an unusual predilection for certain tissues in the human host where cells derived from the neural crest occur (e. g. skin, peripheral nerves, adrenal medulla). Biochemical studies have revealed that M. leprae contains an unusual form of the enzyme diphenoloxidase which has not been detected in other mycobacteria. The presence of a specific glutamic acid decarboxylase in the organism has been demonstrated. Although a few enzymes of glycolysis and tricarboxylic acid cycle have been investigated, nothing characteristic of the bacterium has been discovered, and how M. leprae derives energy for its survival and proliferation still remains obscure.
Degradation of aromatic amino acids in Candida maltosa
Authors: Lippoldt A. , Bode R. , Birnbaum D.
Published: February 2007

The degradation of l‐ and d‐aromatic amino acids has been studied in Candida maltosa. The following main metabolites were indentified: indolelactate was the degradation product of tryptophan, phenylpyruvate and phenyllactate were that of phenylalanine and p‐hydroxyphenylpyruvate and p‐hydroxyphenyllactate resulted from degradation of tyrosine. The first step of utilization of l‐aromatic amino acids was found to be a transamination. The cells contained increased aromatic aminotransferase activity if grown on medium supplemented with one of the three l‐aromatic amino acids. Three aromatic aminotransferases were separated by DEAE‐cellulose chromatography. The pathway for degradation of d‐aromatic amino acids involves deamination as the initial step. The enzyme was characterized to be a general d‐amino acid oxidase capable of utilizing various d‐amino acids. Synthesis of this enzyme was constitutive. Common products of both enzymatic reactions with the aromatic amino acids were the corresponding aromatic pyruvates. Formation of the aromatic lactate derivatives was catalyzed by an aromatic lactate dehydrogenase. This enzyme possessed a high substrate specificity for p‐hydroxyphenylpyruvate, phenylpyruvate, and indolepyruvate and was synthesized constitutively.
Contribution to the taxonomy of methanotrophic bacteria: Correlation between membrane type and GC‐value
Authors: Meyer Jutta , Haubold R. , Heyer J. , Böckel W.
Published: February 2007

Thirty‐nine isolates and additional reference strains of methanotrophic bacteria were studied with respect to mol % G + C of their DNA and the type of intracytoplasmatic membranes. The results on the whole confirm the former classification scheme of Whittenbury et al. (1970). However, problematic groups such as “Methylocystis” and “Methylobacter” are in need of additional taxonomic studies.
Mn2+ transport in the unicellular cyanobacterium Anacystis nidulans
Authors: Singh D. P.
Published: February 2007

Mn2+ uptake by wild type of Anacystis nidulans IU 625 follows Michaelis‐Menten type kinetics with apparent saturation at 27 μmol/l of Mn2+. Lineweaver‐Burk plot of the data reveals a Km of 25 μmol/l and Vmax of 1.2 nmol/mg protein · min. The uptake values at different pH (pH 4.0 to 9.0) exhibit a characteristic profile with an optimum at pH 6.0. The Mn2+ uptake rate in the dark is found to be similar to that in the light suggesting that energy for transport may not be directly derived from light reactions. The system seems to be specific for Mn2+ transport since simultaneous addition of Mg2+ partially inhibited the uptake in a competitive manner. Further, the alterations in Km and Vmax values of mutants with respect to that of wild type strains suggest a genetic control of the transport system.
Interferonsensitivität verschiedener Zellkulturen
Authors: Tonew Marion , Glück Brigitte
Published: February 2007

An economic assay to determine the yield of interferon is necessary for the induction, production and purification of interferon.

Using the inhibition of cytopathic effect of vesicular stomatitis virus in a microtitre system, we compared the susceptibility of different cell lines against an internal IFNα standard obtained from Sendai virus‐induced human leukocytes. Human fibroblasts carrying trisomy G 21 and bovine MDBK cells showed the highest sensitivity followed by normal human fibroblasts. Human RH kidney cells exhibited a susceptibility similar to that of human WISH amnion cells frequently used by others. The human amnion cell line FL and monkey Vero kidney cells, as described here, were unsuitable for the determination of IFN yields.
A plasmid‐containing Flavobacterium sp. isolated from freshwater sediment
Authors: Trevors J. T.
Published: February 2007

During the microbiological examination of freshwater sediment samples for dichloromethane (DCM)‐degrading bacteria, a Flavobacterium sp. was isolated which contained two plasmids with molecular masses (X 106 daltons) of 13.0 and 2.1 as evidenced by agrose gel electrophoresis of cleared cell lysates. This may be one of the frist reports on the presence of plasmids in a Flavobacterium sp.
Proteins tightly bound to DNA and DNA‐synthesizing activity of nucleoids from Escherichia coli
Authors: Gaziev A. I. , Fomenko Ludmila A. , Zakrzhevskaya Dina T. , Petrov S. I.
Published: February 2007

Membrane‐attached nucleoids were isolated from E. coli and separated from proteins by 2 m NaCl. Desintegration of such nucleoids by ultrasound and subsequent centrifugation resulted in the formation of two fractions: a sediment (fraction I) and a supernatant (fraction II). The protein:DNA ratio of fraction I was equal to 27 and was different from that to fraction II (2.6). More than 70% of the proteins not dissociating at 2 m NaCl and bound to DNA of both fractions were polypeptides with molecular weights (Mw) of 31,000–23,000 daltons (31–23 Kdal).

After pulse labelling of the cells with [3H]‐thymidine, the specific radioactivity of newly synthesized DNA associated with fraction I was shown to be considerably higher than that of fraction II. The analysis of DNA‐synthesizing activities in fractions I and II showed that both nucleoid fractions contained DNA polymerase I.

After dissolving the two fractions in 8 m urea – 0.15% sodium dodecylsulphate (SDS) they were chromatographed on hydroxyapatite. DNA‐protein complexes were obtained that did not dissociate at 4 m guanidine. HCI – 5 m urea and 1% SDS. The main protein of the complexes was a 31 Kdal polypeptide tightly bound to DNA.
The production of 3aα‐H‐4α‐(3′‐propionic acid)‐5α‐hydroxy‐7aβ‐methylhexahydro‐1‐indanone‐δ‐lactone by Nocardia restricta mutants
Authors: Miclo A. , Germain P. , Lefebvre G.
Published: February 2007

Two mutants of Nocardia restricta breakdown androst‐4‐ene‐3,17‐dione into 3aα‐H‐4α‐(3′‐propionic acid)‐5α‐hydroxy‐7aβ‐methylhexahydro‐l‐indanone‐δ‐lactone. The metabolic intermediates formed are very different in each mutant. One uses certain aromatic compounds very slowly. A degradation pathway for steroids by Nocardia restricta has been proposed.
The purification and activities of an alkaline protease of Aspergillus clavatus from Nigerian poultry feeds
Authors: Ogundero V. W. , Osunlaja S. O.
Published: February 2007

Optimal growth and extracellular protease production by Aspergillus clavatus Des. was recorded at 30 °C and between days 5 and 7 of the 8‐day incubation period. Purification of this enzyme was achieved by a combination of ultrafiltration, alcoholic precipitation and fractionation on DEAEcellulose and Sephadex‐G.200. A single peak of an alkaline protease was subsequently obtained with a 9‐fold increase in specific activity and a final recovery value of 26.2%.

The enzyme had optimal activity at 37 °C and a pH of 7.8. The enzyme did not degrade leucine amide, hippurylphenylalanine and hippurylarginine indicating lack of exo‐protease activity. However, endo‐protease activity led to a rapid hydrolysis of gelatin with optimal activity at 40 °C and pH 7.8. The high incidence of A. Clavatus on Nigerian poultry feeds vis‐a‐vis the potential health risks posed to farm animals is discussed.
Degradation of phenolic compounds by the yeast Candida tropicalis HP 15. II. Some properties of the first two enzymes of the degradation pathway
Authors: Krug M. , Straube G.
Published: February 2007

The first two enzymes of the phenol degradation pathway were determined and characterized in crude extracts from Candida tropicalis HP 15. The phenol hydroxylase (EC 1.14.13.7) was a stable NADPH2‐ and FAD‐dependent enzyme with a pH‐optimum of 7.6 to 8.0 and a broad substrate specificity. Influence of ultrasound rapidly reduced the enzyme activity.

The catechol 1,2‐oxygenase (EC 1.13.1.1) had a broad pH‐optimum between 7.5 and 9.6 and a limited substrate specificity. Two active protein bands indicating the presence of two isofunctional enzymes were detectable after electrophoretic separation of crude and partially purified extracts on polycrylamide gels and specific staining for catechol 1,2‐oxygenase activity.
Purification and properties of an acylamide amidohydrolase (E. C. 3.5.1.4) with a wide activity spectrum from Brevibacterium sp. R 312
Authors: Thiery A. , Maestracci M. , Arnaud A. , Galzy P. , Nicolas M.
Published: February 2007

An amidase with a wide activity spectrum was purified from the Brevibacterium sp. R 312 and studied. The purification was performed by precipitating the proteins of the supernatant fraction obtained after centrifugation of sonicated cells. The resulting proteins were submitted to a gel filtration step followed by DEAE‐Sephadex ion exchange chromatography and then by another gel filtration process. The purified amidase had a molecular weight of 180,000 and was composed of four subunits of the same molecular weight (43,000 + 2,000). Its isoelectric point was 3.5. This enzyme was able to hydrolyze a large number of amides into their corresponding organic acids and it also possessed an acyl transferase activity.
Self‐resistance of the nourseothricin‐producing strain Streptomyces noursei
Authors: Haupt I. , Thrum H. , Noack D.
Published: February 2007

The nourseothricin producer Streptomyces noursei is resistant to its own antibiotic in submerged as well as in surface culture. The strain shows no cross‐resistance to miscoding inducing aminoglycoside antibiotics. Cell free extracts of Streptomyces noursei inactivate nourseothricin by enzymatic acetylation. The pattern of cross‐resistance of Streptomyces noursei correlates well with the substrate specificity of the nourseothricin acetyltransferase. Furthermore, the acetyltransferase activity parallels the resistance level in nourseothricin‐producing strains and nonproducing mutants. The results suggest that the nourseothricin acetyltransferase is important in the self‐defence strategy of the nourseothricin‐producing strain.
Physiological studies on pBR 322 DNA amplification in an Escherichia coli relA strain
Authors: Hecker M. , Schroeter A. , Mach F.
Published: February 2007

Amino acid limitation leads in E. coli relA cells which cannot synthesize guanosine tetraphosphate (ppGpp) under these conditions to an amplification of pBR 322 DNA. We previously proposed that ppGpp produced in E. coli relA+ cells subjected to amino acid limitation inhibits pBR 322 DNA replication (Hecker et al. 1983).

In further experiments it was established that an E. coli relA strain shows plasmid amplification during amino acid limitation (arginine, threonine, leucine or histidine) only in the presence of sufficient concentrations of phosphate, ammonia and glucose. Plasmid amplification does not occur if ammonia or phosphate is depleted. We suggest that glucose, ammonia and phosphate are needed for nucleotide and deoxynucleotide synthesis as the essential prerequisite for plasmid amplification.

The activity of β‐lactamase was determined as an indicator for the expression of plasmid‐encoded genes. The enzyme activity remains on a low level during plasmid amplification because of arginine exhaustion. A remarkable increase in the activity of β‐lactamase was observed after resumption of growth of relA cells containing amplified plasmid DNA. The plasmid content decreased as the cells continued to grow. We found that plasmid amplification and expression of plasmid‐localized genes are opposite reactions which do not occur at the same time.
Bioconversion of steroids by Cochliobolus lunatus. I. Transformation of Reichstein's compound S with cell‐free preparations of Cochliobolus lunatus
Authors: Hörhold Cläre , Undisz Katrin , Groh H. , Sahm Renate , Schade W. , Komel R.
Published: February 2007

Steroid 11β‐hydroxylase activity and 20β‐hydroxy‐steroid dehydrogenase activity were found in the cell‐free crude extract of Cochliobolus lunatus. It was possible to separate these two enzymatic activities by centrifugation at 100,000 X g. The 20β‐hydroxy‐steroid dehydrogenase activity remained in the supernatant while the 11β‐hydroxylase activity was present in the sediment. 11β‐hydroxylation was clearly inhibited by CO.
Screening among nocardioform bacteria for strains able to degrade aniline and monochloroanilines
Authors: Janke D. , Schukat B. , Prauser H.
Published: February 2007

A total of 106 strains of nocardioform bacteria were chosen from the IMET Culture Collection and checked for their ability to degrade aniline. Among them only four Rhodococcus strains proved to be capable of removing aniline from a liquid mineral salts medium devoid of any other carbon and nitrogen source. This capability was found to be due to total degradation of the aromatic substrate via the β‐ketoadipate pathway which is initiated by the action of inducible oxygenating enzymes. Without any exception, the ring‐cleaving enzymes induced during cell precultivation with aniline were pyrocatechases of the “ordinary” type.

None of the four aniline‐assimilating Rhodococcus strains could utilize any of the monochloroaniline isomers as the sole carbon and energy source for growth. However, resting aniline‐grown cells of these strains mediated the turnover of 2‐ and 3‐chloroaniline in the presence of chloramphenicol. The respective rates were substantially higher (31 to 59% as compared with the unsubstituted aniline) when glucose was provided as the additional carbon substrate. In contrast, 4‐chloroaniline turnover occurred with low rates (3–6%), even in the presence of glucose. With all of the four Rhodococcus strains under study, 3‐chloroaniline turnover resulted in chloride levels which corresponded to an almost stoichiometric dechlorination of the substrate. 2‐Chloroaniline, however was only partially dechlorinated even in the presence of glucose indicating that certain chlorinated metabolite(s) was (were) accumulated in the respective incubation media.
Growth and autolysis of the ascomycete Hypomyces ochraceus. Metabolism of U‐14C‐l‐leucine, 2‐14C‐dl‐threonine and U‐14C‐l‐aspartic acid
Authors: Röber B. , Riemay K. H. , Hilpert A.
Published: February 2007

The autolytic process observed in fungi has been divided into three different phases A 1, A 2, A 3. Each of which is characterized by specific metabolic evants. Recently, we characterized these phases by means of 14C‐d‐glucose. In this communication we report on the uptake and conversion of 14C‐labelled amino acids. These amino acids were rapidly taken up by the fungal mycelium and incorporated into cellular pools. During autolysis phase A 1 these amino acids were still used for protein synthesis. The autolytic process resembled a turnover process during this first phase. At this time the mycelium still exhibited high metabolic activity. The second phase, A 2 was characterized by a rapid intracellular degradation of compartmental material and accompanied by oxidation of the products formed. This was reflected by an increasing 14CO2 production. During phase A 3 products of intracellular degradation and possibly compounds from autolysing hyphae were still taken up by intact, i. e. living compartments of the hyphae and converted to heat and CO2.

Almost no radioactive material was released into the medium during the last two phases. Metabolically active compartments or parts of the hyphae were present during the whole process of autolysis of fungal batch culture, .i e. even at the end of phase A 3.
Mercury methylation by bacteria
Authors: Trevors J. T.
Published: February 2007

Bacteria capable of methylating Hg2+ have been isolated from sediment, water, soil and the gastrointestinal tract of humans. However, very little is known about the physiology and genetics of the mechanisms controlling Hg2+ methylation. Mercury methylation can be either chromosomal or plasmid‐encoded in bacteria. In addition, the extent of nonbiological methylation is not well understood in environmental samples, where there are numerous physical, chemical and biological factors that control the methylation process.

It is known that methylation of Hg2+ is mediated by a series of enzymatic reactions that are also responsible for the anaerobic evolution of methane. However, under highly reduced environments the reaction can also occur nonbiologically. It is possible that certain bacteria use methylation as a resistance/detoxification mechanism.
Chemoautotrophic growth of Thiocystis violacea, Chromatium gracile and C. vinosum in the dark at various O2‐concentrations
Authors: Kämpf Charlotte , Pfennig N.
Published: February 2007

The influence of various O2‐concentrations on chemoautotrophic growth was determined in the range from microaerobic to aerobic conditions. Chromatium vinosum D, Thiocystis violacea 2311 and Chromatium gracile 25‐1 were grown chemoautotrophically using consecutively repeated batch cultures. Rapid growth of all three strains occurred only under microaerobic conditions. The fastest growth (μ = 0.058) was obtained with Chromatium gracile 25‐1 grown in the presence of 1 mg O2 · 1−1. For optimal chemoautotrophic growth sulfur‐containing cells had to be supplied continuously with extracellular electron donor. Multiplication of thiocystis violacea 2311 and Chromatium gracile 25‐1 was significantly inhibited after several cell generations, while Chromatium vinosum D could be grown unlimited. In case of the latter bacterium any given O2‐concentration determined a unique growth rate and a unique specific bchl α content. The analysis of absorption spectra of whole cells revealed that different pigment complexes were regulated separately by oxygen. Growth yields were not dependent on the O2‐concentration. A growth yield of 12 g dry cell mass per mol of thiosulfate oxidized was determined for Chromatium vinosum D growing in the micro‐ to semiaerobic O2‐concentration range. When compared to phototrophically grown cells, the catalase content of chemotrophically grown cells was 2 times lower while the maximal specific respiration rate of the cells was 7 times higher. The ecological significance of the kinetics of chemotrophic growth under various growth conditions is discussed.
Developmental studies of Claviceps paspali seed cultures for the submerged production of lysergic acid derivatives
Authors: Sočič H. , Gaberc‐Porekar V. , Pertot E. , Puc A. , Miličić S.
Published: February 2007

Metabolic pattern of mycelial Claviceps paspali seed cultures during the submerged cultivation was established. By comparing it with conidial and mycelial Claviceps purpurea strains it was found that the biosynthesis of RNA, DNA, and proteins followed a similar course in all Claviceps strains, so the fall of RNA content in mycelium may be considered a general biochemical indicator for optimally developed inoculum. But, two different patterns of carbohydrate and lipid metabolism were observed one for condial and one for mycelial strains.
Effect of oxygen Iimitation on the content of n‐hexadecane‐inducible cytochrome P‐450 in Acinetobacter calcoaceticus strain EB 104
Authors: Sharychev A. A. , Matyashova R. N. , Losinov A. B. , Asperger O. , Kleber H.‐P.
Published: February 2007

The content of cytochrome P‐450 as a function of oxygen supply was studied during growth of Acinetobacter on n‐hexadecane in batch cultures at constant pH. and agitation. The rate of growth and the content of cytochrome P‐450 were not affected as long as the dissolved oxygen tension ranged above 3 to 5% of saturation. The amount of cytochrome P‐450 increased when the oxygen tension declined to zero. Cytochrome P‐450 levels of about 0.3 to 0.4 nmol/mg protein, i.e. a more than a threefold increase, were observed under conditions where oxygen supply was strictly limited and allowed to maintain only a minimum of metabolism or growth. Limited oxygen supply exerted a special effect on the induction of the cytochrome P‐450 as concluded from an increasing ratio between cytochrome P‐450 and cytochrome o, and from the absence of cytochrome d in cells with elevated content of cytochrome P‐450. The increased formation of cytochrome P‐450 was a reversible process.
Introduction of oxygen function into isoprenoid systems by means of Botrytis cinerea (Persoon)
Authors: Dmochowska‐Gladysz J. , Kolek T. , Siewiński A. , Derdziński K. , Zabża A. , Nespiak A.
Published: February 2007

The introduction of oxygen functions into (±)‐1‐(2′,2′,3′‐trimethyl‐3′ ‐cyclopenten‐1′ ‐yl)‐propan‐2‐one [(±)‐1a], (±)‐1‐(2′,2′,3′,‐trimethyl‐3′‐cyclopenten‐1′ ‐yl)‐butan‐2‐one [(±)‐1b], and (±)‐1‐ (2′, 3′, 3′‐trimethyl‐3′ ‐cyclopenten‐1′ ‐yl)‐pentan‐2‐one [(±)‐1c)] by Botrytis cinerea was carried out by hydroxylation in α position with respect to the double bond, or by epoxidation of the double bond itself. The main products had the hydroxy group at the methyl on the double bond. Simultaneously, a hydroxylation at the C′‐5 position in 1a and 1b was observed. In 1e, an additional hydroxylation occurred at the C‐4 position of the side chain. All the reactions were enantiospecific.
Restriction enzyme map of cryptic plasmid accompanying pR711b and pR409; identity of pR409 and pR388
Authors: Heidorn Jacqueline V. , Valentine Carrie R. I.
Published: February 2007

A reference strain containing the IncW plasmid, pR409, was found to contain also a cryptic, conjugative plasmid, here named pJR15. After the separation of the two plasmids into different strains of bacteria, pR409 was found to have an identical restriction enzyme map to the IncW plasmid, pR388. Both pR409 and pR388 were isolated from the same hospital in London and confer sulphonamide and trimethoprim resistance. Orginally pR409 was reported to confer resistance to tetracycline, but this was not confirmed by the Plasmid Reference Center. pR409 appears to represent another isolate of pR388 in a different host background. The restriction enzyme map of the cryptic plasmid, pJR15 (39 kb), has been determined. pJR15 was found compatible with plasmids from 15 different incompatibility groups and has been found also in the reference strain of the IncD plasmid, pR711b. The HindIII and BglII digests of pR711 b are shown. The possible presence of the conjugative plasmid, pJR15, should be examined for studies on the sex pili or chromosomal mobilization properties of pR711b.
A new killer brewing yeast capable of degrading dextrin and starch
Authors: Janderová B. , Davaasurengijn T. , Vondrejs V. , Bendová O.
Published: February 2007

Hybrid strains able to ferment dextrins and to produce killer toxin were constructed by induced protoplast fusion of the brewing strain Saccharomyces uvarum P9 with two different strains of Saccharomyces sp.: the killer strain S. cerevisiae T 158 C and strain S. diastaticus (CCT 21‐49‐9‐a donor of dex genes). Hybrid strains decrease the amount of dextrins in fermented wort and are capable of eliminating heavy contaminations by sensitive strains of Saccharomyces sp.
DNA rearrangements associated with instability of an arginine gene in Streptomyces coelicolor A3(2)
Authors: Flett Fiona , Platt Jacqueline , Cullum J.
Published: February 2007

Streptomyces coelicolor A3(2) gives rise to spontaneous chloramphenicol sensitive mutants at a frequency of about 0.3% per spore. These mutants are often genetically unstable and give rise to arginine auxotrophs (Arg−) at frequencies of 1–7% per spore. These Arg− mutants usually lack the enzyme argininosuccinate synthetase (one exception was found that lacked ornithine carbamoyltransferase) and were shown to have deleted the corresponding argG gene by hybridisation analysis using a cloned S. cattleya argG gene. The Arg− strains also showed a variety of different DNA amplification and deletion events in a region homologous to an amplified DNA sequence found in spontaneous Arg− mutants in S. lividans 66.
Increase of nucleoid size with increasing age of hyphal region in vegetative mycelia of Streptomyces granaticolor
Authors: Kretschmer Sigrid , Kummer Christel
Published: February 2007

In mycelia of Streptomyces granaticolor grown in liquid cultures the distribution of DNA was surveyed by staining and autoradiographic methods. The frequency of stained nucleoids was rather similar in young and old hyphal regions. However, the size of the nucleoids increased with the age of a hyphal region. The degree of heterogeneity in nucleoid size was particularly high during slow growth. In the autoradiograms silver grains (3H‐thymidine label) were also heterogeneously distributed along the hyphae. Calculation of the average number of silver grains per nucleoid revealed that the amount of DNA per nucleoid was 1.6 times higher in the more distant subapical regions than within the 35 μm long apical region.

From a chase experiment it became obvious that the DNA segregated in a normal manner only within the apical region. When the chase lasted for one doubling time, the frequency of silver grains was reduced to 50% only within the about 30 μm long apical region. The label incorporated subapieally remained almost constant, therefore, indicating a lack of normal segregation. Only about 10% of the label was lost by branching. The lack of segregation of sister nucleoids after repeated rounds of replication was found to be responsible for the increase of nucleoid size within subapieal hyphal regions.
The role of copper(I)‐nicotinic acid complex on kojic acid biosynthesis by Aspergillus flavus
Authors: Megalla S. E. , Nassar A. Y. , Gohar M. A. S.
Published: February 2007

Addition of cooper‐monovalent‐nicotinic acid complex to a synthetic medium specific for kojie acid production by Aspergillus flavus enhanced the production by about 47%. The substance is proposed to act via a biochemical utilization of the copper(I)‐B3 complex in a manner similar to that of the naturally utilized nicotinic acid. NAD and NADP like carriers with higher reactivity have been predicted.

According to this prediction the biosynthetic route of kojic acid has been interpreted on the basis of a model proposed by BAJPAI et al. (1981). In this model the enzymes participating are dependent on NAD and NADP (glucose dehydrogenase and gluconate dehydrogenase) as well as on other reduction processes.
Transactivation of several genes of two native Serratia prophages after superinfection by phage kappa
Authors: Steiger H. , Garbe T. , Güleke R. , Gencic Simonida
Published: February 2007

Serratia marcescens HY bacteria must be lysogenic with either prophage y or ψ to make it possible for phage χ to form plaques unless they carry a so‐called ink mutation. Genes in y and ψ termed any and anp were identified that after infection of ink+ cells are necessary for an effective propagation of these phages as well as of coinfecting χ phage. When χ infects y and/or ψ‐Iysogenic cells it transactivates the respective prophage genes by means of two early genes termed tay and tap. It appears that on infection of nonlysogenic ink+ cells χ damps its own development, provided the regulatory region of the responsible gene is undermethylated. After χ infection duly to achieve the special methylation of this region seems to be the function of any and anp.

There are some more genes in y and ψ prophage under the control of tay and tap, concerning in both cases a Dam methylation (recognition sequence GATC) of χ DNA, a recombination proneness under restricting conditions of χ DNA not modified by the modification enzyme of HY, and the χ plaque size. By hybridization studies a region of homology common to y and ψ was demonstrated which from its size might comprise all the transactivated genes. The view is supported by genetic data indicating an affinity among the any and anp genes.

Investigation of various any mutants were indicative of DNA inversions in this region of the y genome. Surprisingly some of the any mutants had become sensitive in their plaque forming ability to an inhibitory activity exerted by prophage ψ. Mutants of ψ unable to interfere but still able to lysogenize were isolated. A model is presented accounting for the formation of pleiotropic and nonpleiotropic mutations with Any phenotype and their reversion types. Possible functions of the y genes and their counterparts in ψ are discussed.
RNA polymerase binding sites on a plasmid R6K derivative with increased copy number
Authors: Nešvera Jan , Klaus Siegfried , Štokrová Jitka , Hochmannová Jitka
Published: February 2007

The specific binding of Escherichia coli RNA polymerase molecules to the DNA of plasmid pNH602, a deletion derivative of R6K having an increased copy number, was detected by electron microscopy. Seven strong RNApol binding sites were found on pNH602 DNA linearized with BamHI or EcoRI restriction endonuclease. All of these specific sites occur in genetically defined regions of the pNH602 molecule. Two of them correspond with the recently reported transcription initiation sites within a region essential for plasmid R6K replication.
Proteasen in differenten Membranfraktionen von Acinetobacter calcoaceticus
Authors: Fricke B. , Jahreis G. , Sorger H. , Aurich H.
Published: February 2007

Distinct protease activities were found in membrane fractions from Acinetobacter calcoaceticus grown on acetate‐NH+4 medium until early stationary phase. Mechanical or enzymatic cell disintegration followed by membrane fractionation through sucrose gradient revealed higher activities in the outer membrane than in the cytoplasmic membrane. Using azocasein and synthetic p‐nitranilides as substrates we found very low proteinase activities in intracytoplasmic membrane fractions. However, these fractions contained a significant aminopeptidase activity which was absent from cell envelope membranes. Peptidolytic activities in intracytoplasmic membranes of gramnegative bacteria have not been described before.
Use of salicylate to estimate the “threshold” inducer level for de novo synthesis of the phenol‐degrading enzymes in Pseudomonas putida strain H
Authors: Janke D.
Published: February 2007

A special approach was used to elucidate the “threshold” inducer concentration for coordinative de novo synthesis of phenol hydroxylase(s), catechol 2,3‐dioxygenase and the 2‐hydroxymuconic semialdehyde‐metabolizing enzymes which initiate phenol catabolism in Pseudomonas putida strain H. It is based on cell‐precultivation with glucose (as the carbon and energy source) in the presence of different concentrations of sodium salicylate which proved to be a potent non‐metabolizable inducer in strain H of these enzymes. Subsequent estimation of the activity status of resting cell suspensions and cell‐free extracts, respectively, prepared from those strain H cultures clearly revealed failing de novo synthesis of the mentioned phenol‐degrading enzymes at salicylate concentrations lower than 0.2 mg/1.
Occurrence of phage‐like particles and growth inhibition in Streptomyces chrysomallus
Authors: Krügel H. , Solovjeva N. J. , Fiedler G. , Avraleva I. W. , Schumann G.
Published: February 2007

From Streptomyces chrysomallus variant strains were isolated which inhibited their parent and were autoimmune to the action of the inhibitor (KRÜGEL and FIEDLER 1986). Phage‐like particles released by these variants as well as by strains of Streptomyces lividans and Streptomyces noursei harbouring various plasmids were analyzed by electron microscopy. We did not find any correlation between the presence of plasmids exhibiting different copy numbers or the transfer functions and the release of phage‐like particles. Also, there was no correlation between the occurrence of these particles and the inhibitory activities of the strains.
Use of batch assays to assess the toxicity of atrazine to some selected cyanobacteria. I. Influence of atrazine on the growth, pigmentation and carbohydrate contents of Aulosira fertilissima, Anabaena oryzae, Nostoc muscorum and Tolypothrix tenuis
Authors: Shabana E. F.
Published: February 2007

The data presented in this investigation revealed that the gain in the dry weights of all algae tested was suppressed in herbicide treatments, particularly, at higher concentrations. However, at the lowest dose of the herbicide, the growth inhibition was statistically significant for Anabaena and insignificant for the other organisms. The chlorophyll a content in Anabaena was slightly, however, insignificantly increased at lower concentrations; a phenomenon that was enhanced by increasing the herbicide dose. On the other hand, the pigment biosynthesis was suppressed in all treatments, in Tolypothrix and Aulosira, being more effective and statistically significant in the latter. The pigment accumulation in Nostoc was slightly and insignificantly promoted by all herbicide doses except at the highest concentration where a slight drop was noticed.

The herbicide was most efficient at lower doses, in stimulating glucose absorption by either Nostoc and Anabaena up to 0.1 ppm. Applying higher doses, a remarkable drop was maintained. It induced significant retardation in the sugar uptake by Tolypothrix and Aulosira. This trend was confirmed by increasing the herbicide concentration. In all treatments with atrazine the total carbohydrate accumulation in all test organisms was suppressed and was more effective at the lowest concentration in Tolypothrix and Aulosira, however, of less significant effect in Anabaena and Nostoc. It may be concluded that the toxic effects of atrazine are partially due to its inhibitory effects on the synthesis of carbohydrates.
Peptidases of Lactobacillus casei and L. plantarum
Authors: Abo‐Elnaga Ibrahim G. , Plapp Roland
Published: February 2007

Fractionation of cell‐free extracts of Lactobacillus casei NCDO 151 (grown in MAN's et al. (1960) broth) by polyacrylamide disc electrophoresis showed the presence of 4 constitutive peptidases. The enzymes appear to be a tripeptidase with a narrow substrate specificity, two true dipeptidases with identical broad‐specificity, and a probable carboxypeptidase with broad‐specificity. A probable amino peptidase could also be isolated from the cell‐free extract by density gadient electrofocusing. Growth of the organism in skim milk resulted in the formation of two inducible dipeptidases.

Examination of 5 other strains of L. casei for the presence of the two constitutive dipeptidases and the carboxypeptidase confirmed the results obtained for the species. Some strains, however, had one more peptidase. The peptidases of the strains differed relatively in the activity and substrate specificity from strain to strain. On polyacrylamide gel, the peptidase activity of L. plantarum appeared as one band only, probably of a carboxypeptidase.
Regulation of L‐carnitine metabolism in Escherichia coli
Authors: Jung Kirsten , Jung Heinrich , Kleber Hans‐Peter
Published: February 2007

The metabolization of L‐carnitine was studied using whole cells of Escherichia coli 044 K74. It showed features of an epigenetical control. L‐carnitine and crotonobetaine were able to induce the carnitine‐reducing system. Oxygen and nitrate as electron acceptors, γ‐butyrobetaine as final product of carnitine transformation in E. coli as well as glucose repress the carnitine metabolization. Other betaines and structurally related compounds did not show any effect neither as inductors nor as repressors.