bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences in enzyme activities of Lipomyces starkeyi between cells accumulating lipid and proliferating cells
Authors: Naganuma T. , Uzuka Y. , Tanaka K. , Iizuka H. 
Published: February 2007

AbstractDifferences in intracellular enzyme activities between cells accumulating lipid and proliferating cells were studied with Lipomyces starkeyi, a fat‐producing yeast. When the cells were removed from a medium for lipid accumulation to a medium for cell proliferation, activities of several enzymes on the glycolytic pathway, pentosephosphate cycle, glycerol 3‐phosphate pathway, tricarboxylic acid cycle and fatty‐acid biosynthesis pathway changed. In the proliferating cells, activities of glycerol‐3‐phosphate dehydrogenase (GDH) and ATP citrate lyase were very low, as compared to those in the cells accumulating lipids. Activities of these two enzymes and 6‐phosphogluconate dehydrogenase, particularly GDH, decreased with the addition of zinc ion to the cell‐free extract of the cells accumulating lipid.
Physiologischer Untersuchungen zur Bildung von Hitzeschockproteinen in Bacillus subtilis
Authors: Hecker M. , Richter A. 
Published: February 2007

AbstractThe protein synthesis pattern was investiged in Bacillus subtilis relA after heat shock. Cells of B. subtilis relA can produce heat shock proteins at 44 °C, 48 °C, 50 °C and 52 °C. At 52 °C growth processes are inhibited because the synthesis of vegetative proteins is dramatically restricted. Under these conditions a relatively pronounced synthesis of heat shock protins can be detected (see RICHTER and EHCKRE 1986 for B. subtilis relA+).When cells were exposed to hgh temperature for longer poids before puls‐labelling, the increased synthesis rate of several heat shock proteins is maintained but otehr heat shock proteins are synthesized with a reduced intensity. After a temperature‐shift down the accelerated rate of heat shock protein synthesis is drastically reduced imemdiately after the shift.The function of heat shock proteins wil be discussed from a physiological point of view.
Influence of culture conditions on mycelial structure and polygalacturonase synthesis of Aspergillus niger
Authors: Hermersdörfer H. , Leuchtenberger A. , Wardsack Ch. , Ruttloff H. 
Published: February 2007

AbstractBiosynthesis of polygalacturonase (PG) by A. niger strain R 1/214 correlates with the morphology of mycelium in submerged culture. The mean specific PG‐synthesis (PG‐U · g−1 · h−1) increases with the degree of compactness of mycelium. PG‐production can be optimized by a precise adjustment of the culture conditions after direct spore inoculation (diffuse mycelium) but the high synthesis as by compact mycelium is never obtained. Different reasons for the higher enzyme production by the pellet mycelium are discussed. PG‐synthesis is assumed to be strictly connected with a limitation of nutrient and oxygen supply.
Studies of the influence of nicotinamide on the development of heat resistance in Bacillus cereus T
Authors: Kalita D. K. , Singh R. P. 
Published: February 2007

AbstractEffects of nicotinamide (NA) on the development of heat resistance and sporulation in Bacillus cereus T were studied. It was observed that NA produces more than 95% heat labile spores (80°C for 30 min). The growth and the utilization of poly‐β‐hydroxybutyrate (PHB) is not affected. The heat labile spores were morphologically comparable to untreated spores but the levels of spore specific proteins and dipicolinic acid (DPA) were only 15–20% of the maximum. NA‐treated spores germinate poorly ( 10%) and a storage of 2 months at 4°C causes complete loss of germination characteristics. However, the exogenous addition of DPA or l‐kynurenine completely reverses all effects indicating a possible involvement of L‐tryptophan metabolism in the development of heat resistance.
Glycerol production by Dunaliella bioculata
Authors: Ahmed A. M. , Zidan M. A. 
Published: February 2007

AbstractDunaliella bioculata, a marine unicellular euryhaline green alga, accumulated interacellular glycerol as a response to increaed osmolality due to increased concentrations of NaCl, KCl or sucrose, but not ethylene glycol. A decrease in salinity, below the normal, of the outer medium resulted in a decrease in the intracellular glycerol. Glycerol was retained (NaCl salinization) or released (KCl salinization) by the alga. Glycerol production slightly depended on photosynthesis since it took place in the light and in the dark.
Amikacin‐acetyltransferase (AAC‐6′/I) encoded by an IncH2 plasmid (pIE866) in Escherichia coli strains
Authors: Voigt Wolfgang , Tschäpe Helmut , Heier Horst 
Published: February 2007

AbstractAn amikacin resistance plasmid was detected in E. coli wild type strains isolated from polluted surface water. This conjugative 145 Md plasmid belongs to the IncH2 group and specifies amino‐glycoside‐acetyltransferase AAC‐6′/I activity.
Growth response of Calothrix marchica LEMM var. intermedia RAO to exogenous organic substrates and distillery effluent in the light and dark
Authors: Adhikary S. P. 
Published: February 2007

AbstractCalothrix marchica LEMM. var. intermedia RAO has been found to grow abundantly in soil receiving the effluent of a molasses distillery. The effluent at low concentrations (1–10%, v/v) and at neutral pH increased the growth of the organism. The cyanobacterium grew photoheterotrophically as well as chemoheterotrophically in the medium supplemented with sucrose and lower concentration (10%, v/v) of neutralized distillery effluent. The exogenous carbon sources were also utilized probably in certain specific biosynthetic process, for example, in the synthesis of sheath layer around the trichome of the cyanobacterium. Formation of sheath was not observed in the medium with mannose, pentoses and organic acids which did not support the heterotrophic growth.
Strain selection in Kluyveromyces marxianus var. lactis for galactose production
Authors: Marin M.‐Hélène , Boze Hélène , Moulin G. , Galzy P. 
Published: February 2007

AbstractAfter treatment with ethy1‐methane sulfonate (EMS) mutants of Kluyveromyces marxianus var, lactis altered in galactose metabolism were obtained which were further imporoved by genetic recombination. Six types of mutants were detected. In batch culture strains with double mutations — either in galactokinase and uridyltransferase, or in galactokinase and epimerase‐ and which also had a galactose permease transformed lactose to galactose and galactitol. Strains with the same double mutations but no galactose permease completely hydrolyzed lactose to galactose and galactitol under continuous culture.
An antibiotic‐overproducing mutant of Streptomyces granaticolor with impaired differentiation
Authors: Šťastná Jana , Blumauerová Margita , Janda Ivan , Ludvík Jiří , Čáslavská Jana 
Published: February 2007

AbstractA thy− tetracycline‐resistant mutant of Streptomyces granaticolor was prepared by mutagenesis of the parental strain ETH 7437. The mutant exhibits a different morphology and an overproduction of granaticins. The ability to form an aerial mycelium and spores has been lost. The mutant cells have a round or an atypical shape and a thick cell wall, the membraneous system is enlarged by numerous mesosomes. Division septa are formed rarely. The mutant is more sensitive to both low and high temperature than the parental strain. The altered features are stably maintained for many generations. Ribosomal proteins of the mutant do not differ substantially from those of the original strain indicating that the mutant phenotype is not due to an alteration at the translational level.
The tricarboxy acid cycle in Acetobacter methanolicus
Authors: Müller‐Kraft Gabriele , Babel W. 
Published: February 2007

AbstractThe acidophilic methylotrophic Acetobacter methanolicus MB 58 possesses a complete set of TCA cycle enzymes. As in neutrophilic methylotrophs, during growth on C1‐compounds the cycle in acidophilic methylotrophs does not work to yield energy. This is also true for chemoheterotrophic growth of Acetobacter methanolicus. However, in the non‐methylotrophic Acetobacter pasteurianus when grown on glycerol, the citric acid cycle seems to operate to yield energy.
Bistable growth pattern of Streptomycetes during continuous cultivation in chemostat
Authors: Noack D. 
Published: February 2007

AbstractStreptomycetes continuously cultivated in a chemostat exhibit a bistable growth pattern characterized by two different growth behaviours, a “disperse” one and a “pellet” one. There exists a distinct range of growth rates within which either growth behaviour can be exerted. The transition between them can be induced by shifting the growth rate above or below critical values by manipulating the dilution rate. Both of them are stable over the same range of growth rates provided that the changing of growth rate within this stability range proceeds successively in moderate steps. This bistable growth pattern is exerted at least by two different species, Streptomyces noursei and Streptomyces “lividans”.
The effects of some protein‐modifying reagents on the interaction of colicins A, E2, E3 and K with their respective Escherichia coli cell receptors
Authors: Šmarda J. , Macholán L. 
Published: February 2007

AbstractColicins attach themselves — through specific protein‐protein interactions — onto receptors in the outer membrane of sensitive bacterial cells. An attempt was made to analyze amino‐acid groups and attractive forces involved in this interaction, following treatment of either colicins A, E2, E3 and K or sensitive bacteria with various physico‐chemical factors and several protein‐modifying reagents. The amounts of colicin bound were checked by a quantitative biological assay.Ionic conditions and specific spatial conformation of both colicin and its receptor molecules are crucial in their interaction and, hence, in the biological effect of colicin.Formaldehyde, naphthalene‐diisocyanate and osmium tetroxide strongly inhibit the binding ability of all colicins tested. The results suggest that NH2 and SH groups are involved in their binding onto receptors; also, CH3S groups seem to be engaged in the attachment of colicins E2 and E3 and phenol‐OH groups in that of colicin K. The possible involvement of further groups (NH, SH etc.) should be checked using more specific reagents. The attitude of colicins E2 and E3 to their common receptor BtuB protein is nearly, but not completely the same.Receptors for all colicins tested should be oxidized to achieve optimal interactions; obviously, carbonyl groups are produced and newly formed anions increase the negative load of bacterial surface. In agreement, reduction of at least colicins A and E3 enhances their receptor binding reactivity. The binding capacity of each receptor can be modulated by a set of amino acid reagents in a specific manner.
Biosynthesis of anthracyclinones
Authors: Eckardt K. , Wagner Ch. 
Published: February 2007

AbstractRecent biosynthetic studies confirmed that anthraquinones are involved as intermediates in the pathway to anthracyclines. The present knowledge in this field has been reviewed. Furthermore, a new generalized order of biosynthetic intermediates from the hypothetical polyketide to aklavinone and related anthracyclinones has been proposed involving tricyclic precursors and 7‐hydroxy‐naphthacenequinones, which also have been found in mutants of anthracycline‐producing strains.
The production of lipases by some Candida and Yarrowia yeasts
Authors: Novotný Čenék , Doležalová Ludmila , Musil Petr , Novák Miroslav 
Published: February 2007

AbstractThe activities of the free and the cell‐bound lipases of Candida rugosa, Candida guilliermondii, Candida curvata, Candida deformans and Yarrowia lipolytica that had been grown on a complex medium with various carbon and nitrogen sources were examined. The highest activities were observed with citrate and succinate as the carbon sources. In some cases olive oil was used as the efficient inducer of the cell‐bound lipases.The cells grown in the presence of the organic nitrogen sources (peptone, urea, soy flour) exhibited higher lipase levels than those cultivated in the medium containing ammonium as the nitrogen source. The extracellular enzyme was detected only in cultures grown with urea, peptone or soy flour as the nitrogen source.
Interaction of bacteriophage 1P with the cell surface components of Rhizobium trifolii 24SM
Authors: Zając Elżbieta 
Published: February 2007

AbstractPhage 1P is a BRADLEY C type with an octahedron head 52 nm in diameter and a short tail 10.2 nm long. The process of phage adsorption in to the host cells has been studied. At first, virions attached themselves to the host exopolysaccharide (EPS) capsule, with subsequent penetration through the capsular layer towards the cell wall. Isolated EPS preparation, composed mainly of mannose, galactose and glucose did not neutralize the phages. The rate of attachment of phage 1P to the mucoid strain R. trifolii 24SM and to its nonmucoid, morphologically rough mutants, 24AR and 24R, is the same. The cell wall of R. trifolii 24SM contains lipopolysaccharide (LPS) receptors, which bind phage particles irreversibly. Purified LPS showed a PhI50 value of 0.05 μg ml−1. One particle of phase 1P is neutralized by 5 × 10−16 g of LPS.
Effect of some photosynthesis‐inhibiting herbicides on growth and nitrogenase activity of a new isolate of cyanobacteria, Nostoc G3
Authors: Gadkari Dilip 
Published: February 2007

AbstractThe effect of the photosynthesis‐inhibiting herbicides Goltix, Sencor, Tycor, Arelon, DCMU, paraquat and atrazine on growth and nitrogenase activity of a new isolate of cyanobacteria, Nostoc G3 was studied. Nostoc G 3 was cultivated under N2‐fixing photoautotrophic conditions. The used herbicide concentrations were in the range or recommended field rates. In the presence of Goltix (50 mg/l and 100mg/l), Arelon (15 mg/l und 30 mg/l), paraquat (10 mg/l and 20 mg/l) and DCMU (1 μM) the growth and nitrogenase activity of Nostoc G3 was almost completely inhibited. The most severe inhibitory effect was observed in the presence of paraquat. Even 1 h treatment of 1 mg/l paraquat caused a total inhibition of growth for 4 weeks. In contrast, the herbicides Sencor (10 mg/l and 20 mg/l) and Tycor (10 mg/l and 50 mg/l) did not cause inhibition of growth and nitrogenase activity. In the presence of atrazine (1 mg/l and 2 mg/l) the nitrogenase activity and the growth were partially inhibited. The results obtained in this study show that cyanobacteria occurring in natural environments are resistant against some of the photosynthesis‐inhibiting herbicides.
Influence of cations on the viability of Halobacterium mediter‐ranei cells
Authors: Muriana F. J. G. , Rodulfo J. D. , Alvarez‐Ossorio M. C. , Relimpio A. M. 
Published: February 2007

AbstractThe effects of monovalent and divalent cations on the cell viability of an extremely halophilic bacteria H. mediterranei were examined. High magnesium concentrations (≧72 mM) were required for stabilization of H. mediterranei cells, although calcium ions were more potent than magnesium in preserving viability. On the other hand, H. mediterranei cells are also able to survive in the presence of monovalent cations, such as ammonium and potassium, at least 14 days. The implications for maintaining stability and neutrality of several cell envelope components by monovalent and divalent cations are discussed.
Bioconversion of Egyptian lignocelluloses by microbial treatment, using Streptomyces viridosporus added to highly reactive polymeric acidified lignin
Authors: Adeeb Zenat , El‐Gammal Amira 
Published: February 2007

AbstractStreptomyces viridosporus degraded lignin and lignocellulose, producing low molecular weight phenolic compounds for potential industrial use.The main portion of lignin in the residues was released into the growth medium as a water soluble modified polymer. The polymer, an acid precipitable polyphenolic lignin (APPL), was recovered from spent culture media by an acid precipitation, and was shown to be mostly free of non‐lignin components, as compared to native lignin. Elemental and functional group analysis showed that APPL contained a higher hydrogen and oxygen content, lower carbon and also lower methoxyl group and higher phenolic content, than native lignin. From IR spectra, an absorption peak at 1,720 cm−1 appeared in the infrared spectra of APPL. The ratio of the absorbance at 1,720 cm−1 to the absorbance at 1.630 cm−1 increased, due to higher levels of carbonyl and carboxyl groups.
Assimilatory reduction of nitrate in Rhizobium meliloti
Authors: Sekiguchi Satoshi , Maruyama Yoshiharu 
Published: February 2007

AbstractNitrate and nitrite reductases in the crude extract of aerobically grown Rhizobium meliloti were determined with methylviologen as electron donor at pH 7. Nitrate reductase was detected in the cells grown in the medium that did not contain nitrate, and in the presence of nitrate the specific activity increased about 2‐fold.Nitrite reductase was induced by nitrate and produced ammonia from nitrite.In nitrate reducing cells, two kinds of O2 labile nitrate reductase were found. One enzyme had optimal pH at 7 and was stabilized to O2 by treating with DEAE‐Toyopearl 650M. The other had optimal pH at 9 and was stabilized by the addition of dithiothreitol and EDTA.Nitrate reductase stabilized by DEAE‐Toyopearl 650M treatment was purified 3,360‐fold from crude extract. The purified enzyme showed a single protein band in polyacrylamide gel electrophoresis, and there was no absorption peak in the visible region. It had a molecular weight of 64,000 in SDS PAGE and 58,000 on Sephadex G‐100 gel filtration. Km for nitrate was 0.9 mM. It was inhibited by p‐chloromercuribenzoate, cyanide, and α,α'‐dipyridyl.
Factor C, a regulatory protein of Streptomyces griseus induces release of potassium from the mycelium
Authors: Szeszák F. , Vitális S. , Szabó G. 
Published: February 2007

AbstractExternal potassium concentration was measured in suspensions of washed living mycelia of Streptomyces strains. An active uptake of K+ by the mycelium was observed from the medium at proper aeration and stirring.The endogenous regulatory protein factor C. in very low concentrations (down to 0.7 ng ml−1), induced in a specific way the release of K+. Changes in the electrolyte composition of the medium had moderate effect on the factor C induced K+ release. Factor C proved to be active in nine different Streptomyces strains. Only S. griseus 45H, the producer of factor C, did not respond. Response to factor C was not affected by chloramphenicol or actinomycin D. The process followed a “slow kinetics” with 3–10 min latency of K+ release.It was assumed that the factor C induced K+ release could be the consequence of a more rapid process realized at the level of existing macromolecules.
Inhibition of ornithine carbamoyltransferase from Pseudomonas syringae pv. syringae W50 by phaseolotoxin
Authors: Jahn O. , Sauerstein J. , Reuter G. 
Published: February 2007

AbstractIn contrast to the producer of phaseolotoxin and Orn‐P(O)(NH2)‐NH‐SO3H (PNSOrn), Pseudomonas syringae pv. phaseolicola, which possesses a sensitive and an insensitive type of ornithine carbamoyltransferase (OCT, E.C. 2.1.3.3.), in Pseudomonas syringae pv. syringae W50, an organism which produce neither phaseolotoxin nor PNSOrn, only one typ of OCT could be detected. This enzyme is highly sensitive to phaseolotoxin. This result supports our hypothesis that the existence of an insensitive ornithine carbamoyltransferase is an important prerequisite for the synthesis of phaseolotoxin in P. syringae pv. phaseolicola and that this enzyme does not occur generally in P. syringae spec.
Fungi on the claws of buffalo and cow in Egypt
Authors: Abdel‐Gewad Khyria M. 
Published: February 2007

AbstractThe frequency of occurrence of fungi in 120 claw samples of buffalo and cow from different localities at Assiut governorate was determined.Thirty‐seven species which belong to twenty genera were collected from the two substrates and the most common genera wereChrysosporium(eleven species ofChrysosporiumwere isolated),AspergillusandScopulariopsis.From the preceding generaChrysosporium sulfureumwas common on cow claws butC. merdariumwas slightly dominant on buffalo claws than on cow claws.Aspergillus flavusandA. nigerwere dominant on buffalo claws, butScopulariopsis brevicauliswas prevalent on cow claws.Also other dermatophytes were isolated such asTrichophyton terrestre, T. rubrum, Histoplasma capsulatum, Phialophora gougerotiiandMicrosporum distortum.
Mycoflora of anise and fennel seeds in Egypt
Authors: Moharram A. M. , Abdel‐Mallek A. Y. , Abdel‐Hafez A. I. I. 
Published: February 2007

AbstractUsing four medium types (glucose‐, cellulose‐, 50% sucrose‐ and 10% NaCl‐CZAPEK's agar), it was possible to isolate 15 fungal genera, 78 species and 6 varieties. The collective fungal spectrum varied from one medium to another where the highest number of species (57 species/1000 seeds) was obtained on glucose‐ and the lowest (31 species/1000 seeds) on 10% NaCl‐CZAPEK's agar.Aspergillus, Penicilliumand sometimesRhizopusandChaetomiumwere the most common genera on the different medium types. The most common fungal species especially on glucose‐ and cellulose‐CZAPEK's agar were,Aspergillus niger, A. flavus, A. ochraceus, A. fumigatus. A. flavusvar.columnaris, Penicillium chrysogenum, Rhizopus stoloniferandChaetomium globosum.Members ofA. glaucusgroup were more frequently recovered on 10% NaCl‐ and 50% sucrose‐CZAPEK's agar.
Screening of microorganisms for enzyme‐inhibiting activities
Authors: Angelov Theodor , Angelova Blaga , Kourteva Yordanka , Stephanova Liliana , Avramova Tatyana , Peretz Valya , Konova Olga 
Published: February 2007

AbstractIn the course of a screening for extracellular inhibitors of 8 different proteinases 140 actinomycete and 150 mould strains were examined. 130 fungal and 50 actinomycete strains were similarly tested for the production of extracellular inhibitors of dihydrofolate reductase (DHFR) and alkaline phosphatase (APh). Most of the inhibitors found in the culture media of the actinomycete and mould strains were specific against serine proteinases. Inhibitors of DHFR were discovered in the culture media of different actinomycetes and moulds. Inhibiting activities towards APh were found mainly in the fermentation filtrates of the mould strains. The approximate molecular sizes of the active substances were determined by using membrane filtration.
In vitrostudies on long‐term stability of R plasmids inEscherichia coliK12
Authors: Böttcher Ingolf , Stelzer Wolfgang 
Published: February 2007

AbstractThe maintenance and stability in anE. coliK12 host of environmental isolates of R plasmids encoding gentamicin resistance during multiple passages in antibiotic‐free and antibiotic‐containing broth were investigated in regard to the conferred resistance phenotypes and the respectiveEcoRI digestion patterns.Only two plasmids belonging to theIncM group maintained stable endonuclease digestion patterns over a 15‐month period in both of the media applied. Other members of this group revealed a considerable variability in theirEcoRI digestion patterns, but a stability in their resistance determinants. TwoIncM plasmids and anIncK plasmid exhibited partial resistance loss under nonselective conditions. The complete segregation of resistance determinants fromIncOF plasmids resulted in a stably maintained cryptic core plasmid.