bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined effects of salinity and temperature on some morphological aspects of four zoosporic fungi
Authors: El‐Hissy Farida T. , Khalil A. M. 
Published: February 2007

AbstractThe quantitative and qualitative formation and deformations of vegetative mycelia, zoosporangia and their discharge, oogonia, antheridia, gemmae, resting sporangia and male and female gametangia varied according to variations in NaCl concentration, temperature and incubation period. Species‐dependent differences were observed.
Critical steps in degradation of chloroaromatics by rhodococci IV. Detailed kinetics of substrate removal and product formation by resting pre‐adapted cells
Authors: Janke D. , Ihn W. , Tresselt D. 
Published: February 2007

AbstractIn kinetic experiments it was demonstrated that turnover of various monochloroaromatic non‐growth substrates (i.e. 2‐chloroaniline, 3‐chloroaniline, 3‐chlorophenol, 4‐chlorophenol, 3‐chlorobenzoic acid) by resting pre‐adapted cells of Rhodococcus sp. An 117 or An 213 typically results in the accumulation of cis‐4‐carboxymethylene‐but‐2‐en‐4‐olide as the principle dead‐end product while cometabolic 2‐chloroaniline turnover by resting aniline‐grown cells of Rhodococcus rubropertinctus IMET 7481 yielded nearly stoichiometric amounts of 2‐chloro‐cis,cis‐muconic acid. Evidence is presented that the observed cometabolic effect of glucose on turnover of the respective monochloroaromatics is primarily associated with their initial oxygenative conversion into chlorocatechols. Based on the described experimental data, it was concluded that the failure of rhodococci to bring about total degradation of chloroaromatics through chlorocatechols is mainly due to the absence in these organisms of a modified ortho‐cleavage pathway (i.e. maleylacetatepathway).
Beladung von Polystyrol Festphasen mit mikrobiellen Erregern und deren Polysaccharid‐Antigenen zum Screening monoklonaler Antikörper
Authors: Mehl M. , Starke R. , Urban Anette , Hoffmann A. , Kiessig St. , Schmidt G. 
Published: February 2007

AbstractBefore screening monoclonal antibodies using enzyme immuno assays, it is necessary to prove that the coating of the solid phases occurs efficiently. The adhesion of whole cells of group B streptococci, Escherichia coli K1, Haemophilus influenzae type b and Candida albicans as well as B‐Streptococcus group antigen, H. influenzae type b capsular antigen, and C. albicans cell wall antigen to polystyrene solid phases was studied and detected by the following methods:.Peroxidase competition procedure, scintillations measurement of 32phosphate‐labelled germs, and reactions with monoclonal antibodies.
Flavovirin — a new antifungal antibiotic produced by the pyrenomycete Melanconis flavovirens
Authors: Sailer Miloslav , Šašek Václav , Sejbal Jan , Buděšínky Miloš , Musílek Vladimír 
Published: February 2007

AbstractThe pyrenomycete Melanconis flavovirens was found to produce a mixture of two antifungal antibiotics. The first has been already described; the antibiotic is identical with thermozymocidin (myriocin). The second antibiotic is a new compound, whose isolation and identification is presented in this paper. The chemical structure of this substance (C21H37NO5) was determined to be 2‐amino‐2‐hydroxymethyl‐3,4‐trans‐epoxy‐14‐oxo‐eicos‐trans‐6‐enoic acid. After the producer it was named flavovirin and it possesses strong activity against yeasts and a moderate effectivity against filamentous fungi.
Quantitation of the relationship between tester cell number inoculated and SOS‐inducing potency of 4‐nitroquinoline‐1‐oxide (4‐NQO) in an automated version of the SOS chromotest
Authors: Janz Siegfried , Wolf Gerhard , Huttunen Tapani , Raabe Ferdinand , Storch Helmi 
Published: February 2007

AbstractThe SOS chromotest is a simple quantitative short‐term bacterial assay for the detection of genotoxic activity of pure compounds or complex samples. On the basis of consecutive experiments aimed at demonstrating the relationship between the inoculum size and the outcome of the test using 4‐nitroquinoline‐1‐oxide (4‐NQO) as model genotoxin. It is shown that within the suitable range of the cell number there is a negative correlation between the number of tester cells and test sensitivity. Moreover, it could be demonstrated that the peak of the dose response curve, i. e., the maximal induction factor, is systematically influenced by the actual value of the ratio of β‐galactosidase to alkaline phosphatase enzyme activities at a 4‐NQO concentration of zero. Last but not least, some simple statistical data describing the performance of the automated version of the SOS chromotest are also given.
On the control of riboxin biosynthesis by Bacillus subtilis
Authors: Malkov M. A. , Tojtman A. I. , Kilfin G. I. 
Published: February 2007

AbstractThe pattern of directed riboxin biosynthesis by Bacillus subtilis was studied in dependence on the cultivation conditions using the material‐energy balance method (MEB).By means of comparative evaluation of experimental and theoretical values of physiological indices received from the MEB equations, we determined the key fermentation periods where it was necessary to change both aeration and mixing regimes. During the period of controled biosynthesis characteristics of self‐regulation of the process have been observed, as expressed by periodical increases and decreases of glucose consumption rate and respiration intensity. The latter was inversely correlated to the velocity of riboxin synthesis and corresponded directly to changes of growth rate.
Plant growth substances produced by microorganisms of the rhizosphere and the soil
Authors: Leinhos Volker , Birnstiel Heide 
Published: February 2007

AbstractMicroorganisms isolated from the soil and the rhizosphere of wheat plants produce growth regulating substances with effects similar to gibberellins when grown in submerse cultures. Bioassays and thin layer chromatography were used for characterization. Different plant growth regulating substances and variations in their quantity were observed among microorganisms. The amounts of gibberellin‐like substances found in culture filtrates varied, in a range from 0.01 to 1.0 mg GA3 equivalents per liter.
Expression of β‐glucosidase and endo‐β‐1,4‐glucanase during development of Chaetomium fusisporale and their characterization
Authors: Sandhu D. K. , Puri R. 
Published: February 2007

AbstractIn the present study, the production of β‐glucosidase and endoglucanase and the pattern of their corresponding polymorphic forms occurring in the extracellular and cytosolic filtrates of Chaetomium fusisporale (ATCC 64772) has been studied. When C. fusisporale was grown on carboxymethyl cellulose (CMC) as the sole carbon source, the extracellular fractions contained most of these enzymes. The distribution of the enzymes varied with the age of the culture. By the use of electrophoretic techniques the presence of two forms of β‐glucosidase, i.e. β‐GLU II and β‐GLU III was detected in extracellular and cytosolic filtrates at early stages of growth, while at later stages two more isozymes of β‐glucosidase, i.e. β‐GLU I and β‐GLU IV, only appeared in the cytosolic filtrates. Similary, endoglucases isozymes EG I and EG II were present in both fractions at early stages of growth but at later stages, with the production of perithecia, EG III appeared. Thus, EG III, β‐GLU I and β‐GLU IV may indicate that they are correlated with the development of the fungus. In order to differentiate further between the multiple molecular forms of these enzymes two of them have been characterized with respect to temperature, pH, ethylenediamine tetra‐acetic acid (EDTA) and metal ions.
Unidirectional internuclear transfer of linked genes in heterokaryons of Candida albicans
Authors: Sarachek Alvin , Lovchik Julie A. 
Published: February 2007

AbstractNutritionally balanced heterokaryons of the naturally diploid, asexual yeast, Candida albicans are produced by fusing protoplasts of complementing auxotrophic strains. Spontaneous unidirectional internuclear transfers of an intact gene linkage group in established heterokaryons is demonstrated. Evidence is presented that a transfer event (i) typically involves a single chromosome which is added to the resident homologues of a recipient nucleus, (ii) can occur equally well in either direction between complementing nuclei and (iii) may encourage gene conversion at transferred loci in the recipient nucleus. The bearing of these findings on application of protoplast fusion to parasexual genetic analysis of C. albicans is discussed.
Relationship between the fatty acid composition and the type of antibiotics produced by Streptomyces lasaliensis
Authors: Podojil M. , Steinerová N. , Cudlín J. 
Published: February 2007

AbstractThe GC‐MS method was used to analyze fatty acids in a parent strain of Streptomyces lasaliensis and its two mutants producing only lasalocid or quinomycin. The biosynthesis of these substances bears relation to differences in the relative proportion of fatty acids. Biosynthetic relationships were revealed between the starter fatty acid units, their precursors, i.e. valine, leucine and isoleucine, and the type of the antibiotic produced.
Sequence‐directed DNA bending upstream of the streptokinase promoter
Authors: Müller Jörg , Malke Horst 
Published: February 2007

AbstractA 450‐base pair (bp) HinfI restriction fragment from the chromosome of Streptococcus equisimilis H46A contains the early coding region of the streptokinase gene (skc), the skc promoter, and a stretch of DNA 5′ to the – 35 region of the skc promoter. Two‐dimensional polyacrylamide (PA) gel electrophoresis at two different temperatures showed that this fragment migrates anomalously slowly on PA gels, suggesting the existence of a bent DNA conformation. Inspection of the nucleotide sequence confirmed this suggestion by revealing numerous oligomeric dA.dT tracts, some of which are in phase with the helix screw. Computer analysis of the sequence predicted the existence of two bending loci, one of which is located upstream of the skc promoter. In addition to showing DNA bending, the 450‐bp HinfI fragment contains multiple 13‐bp sequences homologous to the Escherichia coli integration host factor DNA‐binding consensus sequence. Insertion of IS1 into a site immediately upstream of the – 35 region decreased the expression level of skc in E. coli, suggesting that DNA conformation upstream of the promoter has a role in skc expression.
Some environmental and nutritional factors affecting growth of associated microorganisms of agadagidi
Authors: Sanni A. I. 
Published: February 2007

AbstractA determination of the effect of temperature on growth of the test organisms revealed an optimum range of 30°–37°. From the pH– growth studies, tolerance to low pH levels was observed for all the microorganisms but the optimal range was 5.1–7.2. Various carbohydrates as sources of carbon were utilized.
Microbial synthesis of metabolites with antihypertensive activity: Aspects of fermentation derived inhibitors of angiotensin‐converting enzyme (ACE)
Authors: Manthey Anna , Reuter Gerhard 
Published: February 2007

AbstractIn this review the microbial angiotensin‐converting enzyme inhibitors are described. Especially from the microbiological point of view the characteristics of these metabolites are given, e.g. occurence, fermentation physiology and specificity. Besides these data, the structure, assays and some isolation problems are summarised. Apart from ACE inhibition the different biological activities of these secondary metabolites are discussed.
Streptomyces nucleotide 3′‐pyrophosphokinase are insensitive to stringent control
Authors: Mukai Jun‐Ichiro , Muta Shigeru , Ozumi Yukiko 
Published: February 2007

AbstractThe synthesis of GTP‐ and ATP‐3'‐pyrophosphate by Streptomyces morookaensis nucleotide 3′‐pyrophosphokinase was little affected by the presence of a ribosome‐deacylated tRNA‐poly A,G,U mixture in vitro. The Streptomyces pyrophosphokinases thus do not appear, unlike bacterial stringent factors, to play a significant role in the cellular stringent control.
Amino acids in the mycelium of four isolates of Macrophomina phaseolina pathogenic to groundnut (Arachis hypogaea L.)
Authors: Reddy M. N. , Devi P. Suvarnalatha , Reddy M. Basi 
Published: February 2007

AbstractSingle hyphal tip cultures of Macrophomina phaseolina, isolated from the lesions on pegs, pods, roots and stems of naturally infected groundnut plant, were analyzed for amino acid composition of the mycelium. The isolates varied, both qualitatively and also quantitatively in the composition of amino acids, both free and bound forms.
Degradation of different aromatic compounds by methanogenic consortia from Saale river sediment acclimated to either o‐, m‐ or p‐cresol
Authors: Kaminski Ute , Kuschk P. , Janke D. 
Published: February 2007

AbstractComparative experiments were conducted to examine undefined methanogenic consortia from Saale river sediment acclimated to either o‐, m‐ or p‐cresol for their potential to degrade different aromatic compounds. Each of the consortia under study proved specifically acclimated with respect to the particular cresol isomer used as the substrate during the enrichment procedure and failed to deal with any of the dimethylphenols tested. These findings clearly indicate that the enzyme systems initiating anaerobic (methanogenic) degradation of the different cresol (monomethylphenol) isomers are characterized by a narrow substrate specificity.Degradation of the particular cresol isomers was accompanied by production of methane in amounts which correspond to 89–97% of the theoretically possible yield. In addition, several exogenously added structural analogues (e.g. benzoate, 2‐, 3‐ and 4‐hydroxybenzoic acid, guaiacol, catechol) were degraded with high rates after short acclimation periods or even without any initial delay, depending on the particular type of consortium used.Distinct patterns of degradative activity towards the different aromatic test substrates were observed for the cresol‐acclimated bacterial consortia under study. The results obtained are insufficient to speculate about the precise degradation routes involved. They provide clear‐cut evidence, however, that use of mixtures of methanogenic consortia like those from Saale river sediment acclimated to o‐, m‐ and p‐cresol, respectively, would allow relatively fast biodegradation of a wide range of aromatic compounds under anaerobic (methanogenic) conditions.
Isolation and characterization of four methylotrophic bacterial strains
Authors: El‐Nawawy Amin S. , Banat Ibrahim M. , Elrayes Emad G. , Hamdan Ibrahim Y. 
Published: February 2007

AbstractFour pure methylotrophic bacterial strains isolated from Kuwaiti soil were designated KISRI‐5, KISRI‐6.1, KISRI‐512 and KISRI‐5112, and deposited in NCIMB under NCIB numbers 12135, 12136, 12137 and 12138, respectively. Characterization tests showed that they grew well on methanol and slowly on glucose, at temperatures up to 44 °C and pH 7.0. However, they could not grow on numerous other organic carbon sources. The four strains were very close taxonomically, with minor differences in colony characteristics, lipids pattern, mole G + C% and resistance to certain antibiotics. All strains utilized monomethylamine, but not methane or trimethylamine; all contained ubiquinones with eight isoprene units (Q8), and had C16 as their major fatty acid component. Their characteristics indicate that they are different strains of restricted type M facultative methylotrophs, and could be considered new members of the genus Methylophilus.
Excision of transposon Tn917 in Bacillus subtilis
Authors: Adler Barbara , Hofemeister Jürgen 
Published: February 2007

AbstractExcision of Tn917 from chromosomal sites in B. subtilis is characterized by reversion studies. We propose different modes of excision depending on the site of transposon insertion. Excision takes place as precise excision in one step which results in reversion of the mutant phenotype, or by a two‐step process where nearly precise excision of the transposon moiety is followed by precise excision of the nearly precise excision remnants. For this type of transposons a minor pathway or nonreplicative transposition is proposed to be connected with precise exsision.
Phycomyces blakesleeanus BURGEFF and several wood‐decay fungi in a bioassay for growth factor resources in fresh and microbially precolonized timber
Authors: Grams G. 
Published: February 2007

AbstractThe presence of the essential growth factor thiamine in timber was ascertained with the determination of the mycelial growth figures of several indicator fungi on the respective timber substrates. The behaviour of the absolutely thiamine‐dependent phycomycete, Phycomyces blakesleeanus BURGEFF (Pb), as well as of 6 strains of basidiomycetous wood‐decay fungi (WBF) that did or did not depend on exogenous vitamin supply proved in accordance that (i) both sapwood and heartwood material of 14 native timber species examined were able to furhish fungi with any degree of vitamin dependence with the essential growth factor(s); (ii) both fresh timber and timber pre‐colonized by bacteria, ascomycetous discolouration fungi, and WBF contained thiamine resources above the saturation level of 50 μg per kg; (iii) neither a thiamine supply of 2 to 20 mg per kg total weight nor the residues of microbial pre‐colonizers added to the vitamin pool of timber in that the growth of the test fungi could be further stimulated; (iv) the depressive growth of WBF on vitamin‐free liquid media was not observed on vitamin‐free solid media such as fertilized builder's sand. A vitamin supply did not improve the vigour of WBF of any degree of vitamin dependence, but it was a prerequisite for the growth of Pb on these substrates.It is concluded that vitamins in timber have, on their permanent excessive presence, no ecological significance. They do not add to host wood specificity, to the election of the fungus' host range, to the specialization for gymnosperm wood, to the preference for sapwood or heartwood within the stem, to the establishment of pathogenesis on standing timber, and to the preference for fresh or pre‐colonized wood material.
Characterization of enteroinvasive Escherichia coli serotype 0164 by means of plasmid analysis and virulence assay
Authors: Todorova K. , Bratoeva M. , Daneva M. 
Published: February 2007

AbstractEscherichia coli 0164 is the most prevalent serotype among the enteroinvasive E. coli in Bulgaria and is annually isolated in sporadic, as well in epidemic cases. We studied 243 strains of this serotype, isolated in different regions of the country over the period 1954–1988. The plasmid analysis performed revealed that the presence of large plasmid DNA with molecular size of 140 MDa was related to the virulence of the strains, assessed by the test of SERENY. The absence of this plasmid or its deletion led to the loss of virulence. In 92 % of the strains two small plasmids were demonstrated with molecular size of 6.0 MDa and 4.8 MDa, which appeared to be serotype‐specific. On the basis of the plasmid content of the strains, 7 plasmid profiles were differentiated. The stability of the plasmid profile within a given epidemic focus was confirmed.
Kinetics of secondary metabolite formation by wild type and mutant strains of Streptomyces griseus
Authors: Jacob H.‐E. , Katenkamp U. , Wagner Christina , Fleck W. F. 
Published: February 2007

AbstractIn a particle containing medium, the kinetics of formation of secondary metabolites of a Streptomyces wild type and a mutant strain were determined by spectrophotometric measurements of the anthracyclinone pigments and by the analysis of antibiotic activity of the substances produced. The results were related to the physiological state of the culture derived from the oxygen supply.The total cultivation time was about 400 hours. The production of secondary metabolites started at the end of the logarithmic growth phase (after about 30 hours). During the following cultivation remarkable differences between the two strains regarding the formation of pigments and antibiotics occurred. In the wild type strain producing daunomycinone glycosides and related compounds with antibiotic activity, these antibiotics are active as inhibitors (negative feedback). Therefore, at a certain concentration of antibiotics, the de‐novo formation of anthracycline molecules was impaired. In the mutant strain, as the result of a genetic change, the secondary metabolite production was shifted to nonglycosylated compounds. The production of these substances is not influenced by feedback inhibition as in the case of the wild type strain. From that reason the amount of pigment increased slightly throughout the course of the experiment.Under our experimental conditions the measurement of oxygen supply was a suitable indicator of the physiological state of culture.
The proton extrusion of growing yeast cultures as an on‐line parameter in fermentation processes: Quantitative determination of growth from milligram amounts of substrate in a minimized fed‐batch fermentation apparatus
Authors: Huth Joachim , Werner Sabine , müller Hans‐Georg 
Published: February 2007

AbstractThe proton extrusion of growing yeast cultures was demonstrated to be a very exact and reliable on‐line parameter for the description of the growth of yeasts and substrate consumption in batch fermentation processes. Using this parameter we were able to build up a minimized fermentation apparatus (working volume about 90 ml) which permits the description of growth from substrate amounts of 5 to 50 mg quantitatively in fed‐batch fermentation processes.Using various yeast strains it was demonstrated for nitrogen‐free carbon sources such as hydrocarbons and carbohydrates that1. the course of the proton extrusion indicates qualitatively whether any given carbon source can be utilized as a growth substrate or not, and that2. the amount of proton extrusion is a reliable and reproducible quantitative parameter for growth on the tested substrate.This minimized fermentation apparatus offers advantages and possibilities to detect growth of microorganisms from very small substrate amounts in submerged cultures.
Detection of a 2 μ derivative yeast plasmid with altered properties
Authors: Mink Mátyás , Stülke Jörg , Büttner Knut 
Published: February 2007

AbstractThe Saccharomyces cerevisiae (Sacch. cerevisiae) strain RXII, like many others, harbours plasmid DNAs. and one category of them is homologous to the 2 μ plasmid of yeast. DNA‐DNA hybridization experiments indicated altered structures of this species as regards the number and distribution of the restriction sites. The efforts made to clone either the whole plasmid in pBR328 or its fragments in pBR322 vectors remained unsuccessful, since deleted plasmids were isolated without insert DNA, and even the loss of vector sequences was observed. The data suggest, that the 2 μ derivative plasmid in strain RXII represent an unique category of this extrachromosomal genetic element.
Protein extracts for nutritional purposes from fragile strains of Saccharomyces cerevisiae: Construction of strains and conditions for lysis
Authors: Stateva Lubomira , Venkov Pencho , Lyutskanov Nikola , Koleva Lidia , Hadjiolov Asen 
Published: February 2007

AbstractA superfragile strain, Saccharomyces cerevisiae 211, carrying three nonallelic nuclear determinants of cell lysis by osmotic shock was isolated from the haploid progeny of a cross between two laboratory fragile strains VY 1160 and SY 15. The strain Sacch. cerevisiae 211 is prototrophic, grows well in both laboratory and industrial media, only when supplemented with osmotic stabilizers. The average protein content of its biomass after growth in a molasses‐based nutritional medium is 48.7%. In laboratory conditions this strain releases about 60% of its cellular proteins by spontaneous lysis in water. However, on a pilot scale the protein yield decreases to about 25%. After a single disintegration step at 650 atm, practically all of the cellular protein – 91.5%, is extracted without any additional chemical treatment. This result cannot be reached in any of the wild type strains tested even after triple treatment at 650 atm.