bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of ultraviolet sensitivity of the green alga Scenedesmus obliquus (Turpin) Kuetzing by acriflavine
Authors: Rai U. N. , Agrawal S. B. 
Published: February 2007

AbstractThe effect of pre‐ and post‐irradiation treatments with acriflavine on the kinetics of ultraviolet inactivation of the green alga Scenedesmus obliquus (Turpin) Kuetzing has been studied. Acriflavine is found to modify the UV‐doses. Pre‐irradiation treatment of the alga lessens but post‐irradiation treatment adds to the extent of UV‐inactivation. Incorporation of the dye in the algal suspension during irradiation also elicits a protective effect against UV‐inactivation. The observations are suggestive of an instantaneous uptake and incorporation of the dye in UV‐sensitive components of algal cells‐resulting in altered response of the pre‐, during‐, and post‐irradiation dye‐treated alga to UV and provide evidence for the operativity of two repair system, i.e. light‐independent and light‐dependent repair of the lesions in this alga.
The effect of the sugar‐chain on the bioconversion of tomatines by Nocardia restricta
Authors: Belič I. , Karlovšek M. , Kralj B. 
Published: February 2007

AbstractTomatines are bioconverted by Nocardia restricta to less polar products by conjugation with l (+)‐lactic acid. The yields of these bioconversions decrease from 50% with α‐tomatine to 5% with δ‐tomatine, depending on the length of the sugar‐chain.
Biotransformation of pinenes XVII. Transformation of α‐and β‐pinenes by means of Armillariella mellea (honey fungus), a parasite of woodlands
Authors: Draczyńska B. , Cagara Cz. , Siewiński A. , Rymkiewicz A. , Zabźa A. , Leufvèn A. 
Published: February 2007

AbstractA culture of Armillariella mellea species was adapted to carry out microbial transformations of (+), (‐), and (±)‐α‐pinene magnified image and (‐)‐β‐pinene magnified image. The composition of products obtained indicated that allylic hydroxylation of all substrates was the most characteristic reaction for Armillariella mellea species. The hydroxylation occurred either directly in unchanged pinane skeleton yielding among other compounds verbenol (magnified image) and verbenone (magnified image) or was preceded by a cleavage of four‐membered rings in substrates to form a menthane skeleton. The latter reaction leads to allylic alcohols and diols, mainly trans‐sobrerol (magnified image) and 7‐hydroxy‐α‐terpineol (magnified image).
Freeze‐fracture observations of Corynebacterium glutamicum: the occurrence of an outer membrane‐like structure and the influence of temperature on the cytoplasmic membrane
Authors: Richter W. , Hänel F. , Hilliger M. 
Published: February 2007

AbstractIn order to elucidate temperature‐dependent morphological changes in the cell envelope of the Gram‐positive L‐lysine‐overproducing Corynebacterium glutamicum 9366 we carried out freeze‐fracture investigations of native cells and studied their fatty acid composition. In addition to the cytoplasmic membrane C. glutamicum possesses at the periphery of the cell an additional fracture plane which is unusual in Gram‐positive bacteria and is designated here as outer membrane‐like structure. The fracture faces of this layer display a distinguishable appearance in several regions of the cell. Bacteria grown at various temperatures showed changes in the relation of the saturated to unsaturated fatty acids. We demonstrated that the cytoplasmic membrane was affected by these changes in the fatty acid composition.
Nachweis von Eisen‐Transport‐Aktivität in Pasteurella multocida‐Kulturen
Authors: Flossmann K.‐D. , Grajetzki Ch. , Rosner H. 
Published: February 2007

AbstractIt has been established that Pasteurella multocida cultures possess pronounced iron transport activities to accumulate the iron necessary for growth.Experiments with Fe‐59 confirmed that the bacterial cells are able to acquire iron without direct contact from high molecular iron substrates, such as iron dextrane, ferritine or transferrine. Microbial siderophores of the hydroxamate and phenolate types, such as desferrioxamin B and enterobactine as well as other iron chelators (phenanthroline, citrate and nitrilotriacetate) decrease the bacterial cell growth or iron incorporation and are not relevant for iron transport in P. multocida. The direct analytical identification of siderophores using the reactions by Csaky (hydroxamate type) and Arnow (phenolate type) has proved unsuccessful.The importance of the mannan cell wall polysaccharide is discussed with respect to the iron transport. Thus in terms of iron accumulation, P. multocida is similar to Yersinia, which also possess an efficient transport system for iron not involving siderophores.
Morphogenetic behaviour of two Streptomyces strains analyzed by the use of chemostats
Authors: Kretschmer S. 
Published: February 2007

AbstractStreptomyces granaticolor ETH 7347 and Streptomyces hygroscopicus IMET JA 6599 were cultivated in Casamino acids‐limited chemostats. Amino acids served as sole source of energy, carbon and nitrogen, but their limitation affected primarily the catabolism of the mycelia. At different specific growth rates (μ) samples were withdrawn. After staining the cell walls of the mycelia the average length of the cells (mycelial length per cross wall: L/C) and of the hyphal growth units (mycelia‐length per branch: L/N) were determined.L/C was only slightly influenced by μ. In S. granaticolor the cells were on average 11.5 μm and in S. hygroscopicus about 18.5 μm long.However, L/N was dependent on μ. Upon a shift from μ = 0.6 to μ = 0.1 L/N was reduced 1.2 fold in S. granaticolor and 1.8 fold in S. hygroscopicus. Especially growth rates below 0.2 stimulated branching. The opposite response of L/N to changes of μ was, however, observed in glucose‐limited chemostat cultures (Riesenberg and Bergter 1979). Thus, the average length of the growth units is not determined by μ per se — even if in both cases the energy source was limited — but by specificities of the nutirent‐dependent metabolism.Comparison of L/C and L/N showed that in all samples of S. granaticolor cells were smaller than the hyphal growth units, while they were larger in S. hygroscopicus. From a cellular point of view, thus there exist different mechanisms of branching — the single and the multiple branching — which were discussed.
Production, localization and glucose repression of β‐glucosidase in Trichoderma longibrachiatum
Authors: Sandhu D. K. , Sidhu M. S. 
Published: February 2007

AbstractOptimal 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

AbstractErgotamine 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

AbstractPurified 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

AbstractCandida 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

AbstractTwo 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

AbstractThe 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

AbstractThe 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

AbstractTransferable 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

AbstractThe 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

AbstractDifferent 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

AbstractThirty‐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

AbstractIn 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

AbstractVery 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

AbstractThe 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

AbstractThirty‐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

AbstractMn2+ 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

AbstractAn 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

AbstractDuring 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.