bluuebunny/crossref_metadata_2025_split huggingface dataset:
Occurrence of the general control of amino acid biosynthesis in yeasts
Authors: Bode R. , Schüssler K. , Schmidt H. , Hammer T. , Birnbaum D. 
Published: February 2007

AbstractThe response of three amino acid biosynthetic enzymes, threonine dehydratase, tyrosine aminotransferase and saccharopine dehydrogenase, to conditions of histidine, tryptophan or lysine limitation was investigated in 15 yeast species. The activities of all these enzymes increased about two‐ to fourfold as a result of action of the general control of amino acid biosynthesis in Brettanomyces anomalus. Candida maltasa, Hansemala polymarpa, Rhodosporidium toruloides, Saccharomyces cerevisiae and Yarrowia lipolyilca. No evidence for the existence of the general control was found in Candida brumptii, Candida, utilis, Hansenula anomala, Hansemula henricii, Khuyveromyces marxianus, Pichia gulliermondii, Saccharomycopsn capsularis, Trichosporan adenino‐voranis and Trigonopsis variabilis.
Amplification of pBR322 plasmid DNA in Escherichia coli relA strains during batch and fed‐batch fermentation
Authors: Hofmann K. H. , Neubauer P. , Riethdorf Sabine , Hecker M. 
Published: February 2007

AbstractFermenter studies under batch and fed‐batch conditions were carried out to test the possibility of plasmid pBR322 production in large amounts by using E. coli relA strains. High amplification rates of pBR322 plasmid DNA were observed in E. coli CP79 (relA) and E. coli CP143 (relA) in both batch and fed‐batch cultivation after exhaustion of the amino acid arginine. The concentrations of plasmid DNA per unit of biomass were nearly the same in batch and in fedbatch fermentations of E. coli CP79 and E. coli CP143. Therefore, the significantly higher biomass concentration of the two strains after fed‐batch fermentation gave a dramatic increase in the yield of plasmid DNA per litre of medium in comparison to the batch process.The results support the suggestion that E. coli relA strains are suitable hosts for production of large amounts of ColE1‐derived plasmids for recombinant DNA research.
N‐Acetylmuramic acid inhibits spore germination and germination enzymes
Authors: Brown W. C. , Morrison D. , Sanford W. , Granada S. 
Published: February 2007

AbstractThis report describes the inhibition of spore germination by N‐acetylmuramic acid. At concentrations of 20 mM and higher, the rate of germination of the treated spores was ten‐fold lower than that of the control spores. The inhibitor also depressed the activity of two germination‐related enzymes; a coat‐associated hexosaminidase and a core enzyme. These findings suggests that N‐acetylmuramic acid affects spore germination by inhibition of the corticolytic enzymes. The results are discussed with respect to the possible role of these enzymes in germination.
Studies on the mycoflora of Aswan High Dam Lake, Egypt: Monthly variations
Authors: El‐Hissy F. T. , Moharram A. M. , El‐Zayat S. A. 
Published: February 2007

AbstractFifty‐one species and one variety appertaining to twenty one genera of mesophilic fungi were recovered from the monthly samples of marginal water (44 species, 1 variety and 18 genera) and submerged mud (78 species, 1 variety and 30 genera) of Aswan High Dam Lake during the period from July 1985 to December 1986. The most common species were Aspergillus fumigatus, A. flavus, A. terreus, A. niger and Penicillium funiculosum. The highest fungal populations were almost detected either in October, in December 1985 or in February 1986. Of the 12 thermophilic and thermotolerant fungal species, A. fumigatus and A. nidulans were the most common. Paecilomyces variotii, Rhizomucor pusillus, Thermomyces lanuginosus, Thermoascus thermophilus and Sporotrichum thermophilum were fairly common in one locality or more. The physico‐chemical characteristics of water and mud samples were also followed.
Inhibition of growth of some plant pathogenic fungi by some antagonistic microorganisms isolated from soil
Authors: Ikotun T. , Adekunle Funke 
Published: February 2007

AbstractActinomyces species I and II (tentatively identified awaiting confirmation) and Trichoderma harzianum were isolated from soils grown to cassava plants. The Actinomyces species inhibited the growth of five plant pathogenic fungi at a distance whereas T. harzianum was an active hyperparasite which attacked the mycelia of target organisms (plant pathogens) and prevented their continued growth. The three microorganisms compared favourably with two other established antagonists, Bacillus cereus and B. subtilis. But the species of Actinomyces were especially more active. Soil inoculation of the antagonists have prevented root and tuber rot of cassava plants in the field and are likely to be useful for preventing other soil‐borne diseases of plants.
Synthesis and metabolism of roquefortine in Penicillium species
Authors: Reshetilova Tatiana A. , Kozlovsky Anatoly G. 
Published: February 2007

AbstractThe uptake of exogeneous 14C‐roquefortine by Penicillium farinosum cells and its metabolism was followed. Growth and roquefortine biosynthesis of three Penicillium species during a cultivation period of 14 d were investigated. Furthermore, the effect of cultivation conditions viz. various culture media on roquefortine uptake and biosynthesis as well as biomass production were studied. Some general problems of physiology and metabolic regulation of alkaloid formation in Penicillium species were discussed.
Mechanisms of bacterial degradation and transformation of chlorinated monoaromatic compounds
Authors: Häggblom Max 
Published: February 2007

AbstractChloroaromatics are xenobiotic compounds of environmental concern. They can be removed from the environment by (bio)degradation or by (bio)transformation. Recognition of the mechanisms and requirements of their biodegradation is of cardinal importance for understanding the fate of these chemicals in the environment, and for developing methods for biological treatment of wastes containing compounds of this type.Cleavage of the carbon‐halogen bond is the critical step in degradation of chloroaromatics. As exemplified with chlorophenols, chlorobenzoates and chlorobenzenes in this review, two distinct strategies are employed by bacteria for degradation of chlorinated aromatic compounds: the particular chlorine substituents are removed either directly from the aromatic ring (as an initial step in degradation) or after oxygenative ring cleavage (from chlorinated aliphatic intermediates). Direct elimination of chlorine substituents from the aromatic ring occurs by displacement with either hydroxyl groups (hydrolytically or oxygenolytically) or hydrogen atoms (reductive dechlorination). Dechlorinations of the latter type require reducing power and are significant in anaerobic environments, but have also been observed with strictly aerobic bacteria.Various biotransformation reactions, with only minor alteration of the parent compound, are an alternative to biogradation. Two environmentally significant transformation reactions discussed here are O‐methylation and O‐demethylation. The capability to O‐methylate chlorinated hydroxybenzenes seems to be widespread in bacteria. O‐Methylation is an environmentally important transformation reaction, since methylation increases the lipophilicity of the compound and thus the potential for bioaccumulation. Bacterial O‐demethylation of chlorinated methoxylated compounds has been observed under both aerobic and anaerobic conditions.
Enzyme regulation in in vivo‐constructed Pseudomonas putida strains with two alternative routes for oxidative degradation of phenol
Authors: Janke D. , Kujau M. , Zippel M. , Schöpp W. 
Published: February 2007

AbstractBased on plate matings using P. putida strain BL10 as the recipient and either P. putida strain PG405 or PG125 as the donor, the transconjugant strains TK1 and TK3 were obtained. These were shown to harbour a single plasmid of a molecular size comparable to that of PGH1 (in the donor strain PG405) and pPGH11 (in the donor strain PG125), respectively. Clear‐cut evidence was presented that at least the transconjugant strain TK3 has the genetic potential of degrading phenol via both the ortho‐pathway (encoded by chromosomal genes) and the meta‐pathway (encoded by plasmid‐localized genes) due to two complete alternative enzyme sequences. However, in both transconjugant strains TK1 and TK3 only the meta‐pathway enzymes were found to operate during cell growth on phenol as the sole carbon source. Several lines of investigation indicated the observed predominance of the meta‐pathway in TK1 and TK3 cells growing on phenol to be a specific phenomenon resulting from coordinate induction of the respective plasmid‐encoded enzymes by the primary substrate.
Studies on the mycoflora of Aswan High Dam Lake, Egypt: Vertical fluctuations
Authors: Moharram A. M. , El‐Hissy F. T. , El‐Zayat S. A. 
Published: February 2007

AbstractThe fungal population of Aswan High Dam Lake showed marked vertical variations during the period of study which extended from July 1985 to December 1986. High fungal counts were observed at the surface water which were mainly due to the high counts of Aspergillus fumigatus and A. tertureus. Going deeper the fungal population decreased till 30 meters, then gradually increased to reach its maximum at the 70 meter depth (near the bottom of the lake). Such increase was basically due to the high population of Penicillium funiculosum. At each sampling time, the water temperature and the values of dissolved oxygen were always higher at the surface than near the bottom of the lake. The temperature ranged from 15° to 26 °C and the dissolved oxygen from 1.31 to 8.98 mg 1−1.
Microbial DNA topoisomerases and their inhibition by antibiotics
Authors: Zimmer C. , Störl K. , Störl J. 
Published: February 2007

AbstractSupercoiling of bacterial DNA is regulated by topoisomerases and influences most of the metabolic processes involving DNA. The present review is devoted to a brief outline of the supercoiled state of DNA in bacteria and to all microbial topoisomerases hitherto described. Recent studies on topoisomerases of archaebacteria led to the discovery of a so‐called reverse gyrase, the properties of which are also discussed.Special emphasis is given to a selective treatment of the effects of those antibiotics which act as gyrase inhibitors.
Mapping of the glucoamylase gene of Trichosporon adeninovorans by mitotic haploidization using hybrids from protoplast fusions
Authors: Büttner R. , Bode R. , Samsonova I. A. , Birnbaum D. 
Published: February 2007

AbstractIn two strains of Trichosporon adeninovorans genes of unknown location were assigned to linkage groups. Diploid strains were produced by protoplast fusion and partially haploidized by growth on benomyl causing mitotic haploidization. We show that both strains synthesize an extracellular glucoamylase with different properties. These differences could be used to map the corresponding gene in the segregants. We could map the glucoamylase gene from one of these yeast strains on linkage group II, one of the three linkage groups identified so far.
Occurrence of zoosporic and terrestrial fungi in some ponds of Kharga Oases, Egypt
Authors: El‐Nagdy M. A. , Abdel‐Hafez S. I. I. 
Published: February 2007

AbstractThirty‐nine species belonging to 13 genera of zoosporic fungi were collected from 33 water samples on sesame and hemp seeds as baits at 22 °C. Five genera were isolated in high occurrence:Allomyces(2 species),Achlya(9 species),Dictyuchus(4 species),Pythium(5 species) andSaprolegnia(5 species).Aphanomyces(4 species) andIsoachlya(2 species) were of moderate frequencies. The remaining six genera were less frequent:Anisolpidium, Brevilegnia, Calyptralegnia, Leptolegnia, PythiopsisandThraustotheca.Sixty‐six species and 2 varieties belonging to 34 genera were identified on glucose‐(24 genera and 52 species + 1 variety) and cellulose (31 genera and 48 species + 2 varieties) CZAPEK DOX agar at 28 °C. The most common species on the two media wereAcremonium strictum, Aspergillus flavus, A. fumigatus, A. niger, Fusarium moniliforme, F. oxysporum, F. solani, Mucor racemosus, Penicillium chrysogenum andP. corylophilum.Some fungi were common only on cellulose agar medium such asChaetomium globosum, C. spiraleandMemnoniella echinata.
DNA probes for studying streptothricin resistance evolution in enteric bacteria
Authors: Tietze Erhard , Tschäpe Helmut , Golubev Alexander V. 
Published: February 2007

AbstractProbes for the detection of streptothricin resistance genes have been derived from recombinant plasmids. These include the streptothricin resistance gene probe sat 1/2 derived from Tn 1825 and specific for both the sat‐1 determinant of Tn 1825 and the sat‐2 determinant of Tn 1826, and the probe sat D derived from and specific for the sat‐1 determinant of transposon Tn 1825. A third streptothricin resistance gene probe, sat 3, represents the streptothricin resistance determinant sat‐3 of the IncQ R plasmid pIE639. Hybridization studies did not reveal any sequence homology between sat‐3 and the transposon‐ localized sat‐1 and sat‐2 determinants. Moreover, non of the different sat‐determinants isolated from plasmids of gram negative bacteria hybridized with the analogous resistance determinant of Streptomyces noursei, which had been cloned and named nat by KRÜGEL et al. (Gene, 1988, 62, 209–214). The sat 1/2 probe in combination with the sat D probe proved to be suitable for the identification and the differentiation of sat‐1 and sat‐2 determinants in different genetic environments. Streptothricin resistance genes related to those present on transposons Tn 1825 and Tn 1826 have been detected by hybridization with the probe sat 1/2 on plasmids isolated a long time ago before the application of streptothricins. The sat‐3 determinant appears to be exclusively associated with the IncQ plasmid pIE639.
Mutagenesis of Acetobacter methanolicus MB58 with the transposon Tn5
Authors: Dobrowolski P. , Gründig M. W. 
Published: February 2007

AbstractTransposon mutagenesis was applied to the isolation of mutants of the facultatively methylotrophic Acetobacter methanolicus MB58. The transposon Tn5 (pSU2011) was transferred from Escherichia coli SM 10 by means of conjugation to Acetobacter methanolicus MB 58. Four out of 1850 stable Km‐resistant transconjugants were identified that were formaldehyde sensitive and failed to grow on methanol.
DNA sequences from Saccharomycopsis fibuligera capable of autonomous replication in Saccharomyces cerevisiae
Authors: Jurský František , Hostinová Eva 
Published: February 2007

AbstractA Sau 3AI digest of total DNA from Saccharomycopsis fibuligera was cloned with the yeast‐integrating plasmid YEp24ΔEcoRI and the capacity for autonomous replication (ARS) was assayed in yeast. From eighty clones, five mitoticaly unstable yeast transformants were picked up, recombinant plasmids from these clones were recovered with Escherichia coli, mapped, hybridized with total DNA of S. fibuligera and tested to mitotical stability in Saccharomyces cerevisiae. Experiments suggested the existence of DNA sequences from dimorphic Saccharomycopsis fibuligera with ARS activity in Saccharomyces cerevisiae.
Spontaneous mutations in the galactose operons of Streptomyces coelicolor A3 (2) and Streptomyces lividans 66
Authors: Ali‐Dunkrah Umaru , Kendall Kevin , Cullum John 
Published: February 2007

Abstract17 spontaneous Gal− mutants of S. coelicolor were studied using Southern blottings, but no insertion or deletion mutations were found. 10 mutants of S. lividans included three deletion mutations. The reasons for the lack of insertion mutants are discussed.
Acremonium chrysogenum differentiation and biosynthesis of cephalosporin
Authors: Bartoshevich Yu. E. , Zaslavskaya P. L. , Novak M. J. , Yudina O. D. 
Published: February 2007

AbstractOn the basis of structure‐functional analysis of the development of Acremonium chrysogenum, e.g. under conditions either stimulating antibiotic synthesis or not conductive to production, a scheme was proposed representing the various ways in which morphological differentiation occurs in the culture in dependence on the directions of its metabolism.Three types of culture differentiation were determined. Type 1 differentiation is characterized by the transition of the vegetative stage into the reproductive one with the formation of conidia. Type 2 differentiation is characterized by the formation of typical arthrospores also being the reproductive form. Type 3 differentiation is characterized by the multistage transformation of the mycelium organization into the yeast‐like one which is metabolically more active and is a producer of antibiotics and enzymes.In addition to the defined regularities in the development and differentiation of Acremonium chrysogenum structural peculiarities were observed which could be helpful to the search for regulators or specific enzymes taking part in the culture development.
Autolytic reduction of the nucleic acid content in Candida utilis
Authors: Kossaczká Zuzana , Vojtková‐Lepšiková Anna , Machová Eva 
Published: February 2007

AbstractThe nucleic acid content in Candida utilis was autolytically reduced only after previous lyophilization of yeast cells or pretreatment of the cells with ethyl acetate. These pretreatments provided a sufficient permeability of the cell membrane system and thus enabled a reduction of the nucleic acid content. While deep freezing of the cells (−35 °C) had no positive effect on the degradation of nucleic acids, lyophilization of yeast cells led to a 75% decrease of the nucleic acid content. Furthermore, a 55% reduction of the nucleic acid content was proceeded without a concomitant loss of proteins. Similar results were obtained by using ethyl acetate.
Studies on the early stages of infection of Alternaria alternata on groundnut (Arachis hypogaea L.)
Authors: Prasad P. , Devi P. Suvarnalatha , Reddy M. N. 
Published: February 2007

AbstractStudies were conducted on the early stages of infection of groundnut leaves by Alternaria alternata. Inoculated leaves were periodically sampled, checked for germination of spores, growth of germ tubes, appressorium formation and method of sporulation. Evidence was observed for the entry of the germ tubes through the stomates (with or without the formation of appressorium‐like structures) or through the host surface by the formation of appressoria.
Substratinduzierte cAMP‐Signale in Wildstämmen und Mutanten von Saccharomyces cerevisiae
Authors: Sachse Ottomar 
Published: February 2007

AbstractAddition of glucose or other substrates to starved Saccharomyces cerevisiae cells triggers a cyclic AMP signal which induces the protein phosphorylating cascade. Before the addition of various substrates the wild‐type and mutant yeast strains were arrested at the G1 phase of the cell division cycle by transferring the cells, grown at 26 °C to 36 °C in a synthetic medium without any substrate. After the temperature shift back to 26 °C different substrates were added and the cAMP levels were measured. The highest cAMP levels were observed immediately after the addition of the substrates. A relationship between the maximum growth rate of the individual strains or mutants at a given substrate and the intracellular cAMP level is discussed.
Fungal flora associated with combine harvester wheat and sorghum dusts from Egypt
Authors: Abdel‐Hafez S. I. I. , Moubasher A. H. , Shoreit A. A. M. , Ismail M. A. 
Published: February 2007

Abstract107 species and 8 species varieties belonging to 44 genera were collected from combine harvester wheat and sorghum dusts (35 genera and 91 species + 4 varieties) and from the atmosphere of their hay sites (26 genera and 69 species + 4 varieties) on glucose‐ and cellulose‐CZAPEK's Dox agar at 28 °C and 45 °C. The mycoflora of wheat and sorghum dusts were basically similar on the two types of media and the most common fungi were:Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. ochraceus. A. svdowii, A. terreus, Cochliobolus spicifer, Emericella nidulans, Fusarium moniliforme, Penicillium chrysogenum, P. duclauxii, P.funiculosumandP. oxalicum.Truly thermophilic species were frequently encountered from the two substrates:Chaetomium thermophilum, Humicola griseavar. thermoidae, H. insolens, Malbranchea pulchella var.sulphurea, Rhizomucor pusillus, Sporotrichum thermophilum, Talaromyces thermophilus, Thermoascus thermophilusandThermomyces lanuginosus.The airborne fungi in the two atmospheres were basically similar and the most prevalent species were members ofAlternaria(1 species),Aspergillus(18 species + 2 varieties),Chaetomium(2 species),Cochliobolus(3 species),Emericella(3 species + 2 varieties),Fusarium(3 species),Mucor(1 species),Penicillium(14 species) andStachybotrys(1 species).
The proton extrusion of growing yeast cultures as an on‐line parameter in fermentation processes: Determination of biomass production and substrate consumption in batch experiments with Candida maltosa EH 15 D
Authors: Huth Joachim , Blasig Rosel , Werner Sabine , Müller Hans‐Georg 
Published: February 2007

AbstractUsing the proton extrusion of growing yeast cultures (calculated from the alkali consumption required to maintain a constant pH‐value) it is possible to describe the growth of yeasts and the growth‐related substrate consumption on‐line and to do so more exactly than by determining these values with usual off‐line methods. In batch experiments with Candida maltosa in a mineral salt medium clear linear relationships could be demonstrated between the proton extrusion nH+ and the increase of biomass concentration (determined as dry weight, optical density and protein according to a modified LOWRY‐method) as well as substrate consumption (n‐hexadecane and NH+4 as the C‐ and N‐sources respectively). The biochemical basis of the proton extrusion seems to be connected with the NH+4‐metabolism. The simple on‐line registration of the proton extrusion offers various possibilities to use this value for control of fermentation processes.
Formation of a potent respiratory inhibitor at nitrite reduction by nitrite reductase isolated from the bacterium Paracoccus denitrificans
Authors: Kučera Igor , Skládal Petr 
Published: February 2007

AbstractA new method of dissimilatory nitrite reductase (cytochrome cd1) isolation from the periplasmic fraction of anaerobically grown cells of the bacterium Paracoccus denitrificans was developed, using ionex and gel permeation chromatography with FPLC system (PHARMACIA, Sweden). In experiments with isolated enzyme it was shown that through a nitrite reduction, catalysed by this enzyme, a substance (presumably nitric oxide) was formed which at submicromolar concentrations inhibited terminal cytochrome oxidase of the respiratory chain of the same bacterium. These results help to explain formerly observed sensitivity of bacterial oxidase activity to NO‐2 and the mechanism of switching the electron flow from O2 to nitrogen terminal acceptors.