bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein extracts for nutritional purposes from fragile strains of Saccharomyces cerevisiae: Reduction of the nucleic acid content and applicability of the protein extracts
Authors: Lyutskanov Nikola , Koleva Lidia , Stateva Lubomira , Venkov Pencho , Hadjiolov Asen 
Published: February 2007

Abstract92% of the cellular proteins from the osmotically fragile strain Sacch. cerevisiae 211 (MATa srbl srb2 tsl) were extracted by one passage in a high pressure disintegrator at 650 atm. After isoelectric precipitation, 60.1% of the proteins were isolated. The protein extract was rich in proteins (60–70%) but also contained 12–13% nucleic acids and 13–14 % carbohydrates. Mild conditions were created for simultaneous reduction of nucleic acids and carbohydrates in the lysate prior to precipitation of proteins. Under these conditions the amount of nucleic acids in the protein extract was reduced to 2 %, and that of the carbohydrates to 5.7 %. As a result of the whole procedure on a pilot scale, 1 1 culture of Sacch. cerevisiae 211 grown in molasses based nutritional medium yielded 1 g protein extract. The applicability of this protein extract for nutritional purposes was demonstrated by determination of its amino acid composition, acute toxicity tests with Tetrahymena pyriformis and short‐term animal nutrition tests. The results showed that the protein extract is a suitable source of SCP for nutritional purposes.
Flavonoids in seed coats of two Colutea species: Ecophysiological aspects
Authors: Aguinagalde Itziar , Perez‐Garcia Felix , Gonzalez Aldo E. 
Published: February 2007

AbstractColutea is a genus of great rusticity and is valuable as forage. Its domestication is limited by the low germination rates and high susceptibility of the seeds to fungal attack. Abundant kaempferol, quercetin and myricelin glycosides have been identified from seed coats of Colutea arborescens and C. atlantica. Their ecophysiological role is studied by bioassays: inhibition test of germination of Lactuca sativa; inhibition test of growth of Cladosporium cladosporoides and Sterigmatomyces polyborus isolated from the seed coats.
The proton extrusion of growing yeast cultures as an on‐line parameter in fermentation processes: Ammonia assimilation and proton extrusion are correlated by an 1:1 stoichiometry in nitrogen‐limited fed‐batch fermentations
Authors: Huth Joachim , Werner Sabine , Müller Hans‐georg 
Published: February 2007

AbstractIn preceding papers (HUTH et al. 1990a, b) the proton extrusion nH+ of growing yeast cultures was shown to be an exact and reliable on‐line parameter for the description of biomass production and consumption of the nitrogen (NH4+) and carbon sources quantitatively in batch and fed‐batch fermentation processes.In the present paper we demonstrate that the biochemical basis of this proton extrusion must be connected with the nitrogen metabolism of growing yeasts: A strong acidification was found only during growth on NH4+ as the source of nitrogen, while the pH‐course was different for other substrates. Using NH4+limited fed‐batch conditions we detected an NH4+/H+ exchange ratio of exactly 1.0.The usefulness of the proton extrusion as an on‐line parameter in fermentation control and its range of application are discussed.
Ultrastructural features of microbial colony organization
Authors: Tetz Victor V. , Rybalchenko Oksana V. , Savkova Galina A. 
Published: February 2007

AbstractThe ultrastructure of microbial colonies was studied. Inside the colonies three types of intercellular contacts were demonstrated. In the colonies of Gram‐negative bacteria, the cells were found to be connected by tight adhesions of outer membranes of the cell walls and membrane bridges. In the colonies of Gram‐positive bacteria, the intercellular contacts were formed by fusion of peptidoglucan layers of the cell walls. Bacterial cells were differentiated by the presence of a capsule‐like envelope. The obtained data indicate the existence of elements of cellular cooperation and specialization in microbial colonies.
Citrate metabolism in starved cells of Streptococcus lactis subsp. diacetylactis
Authors: Vilchez F. , Petit C. , Marczak R. 
Published: February 2007

AbstractThe effect of starvation on citrate metabolism by fully grown cells of Streptococcus lactis subsp. diacetylactis was studied by three different procedures.An 8‐hour starvation period in fermented medium decreased citrate uptake rate but diacetyl and acetoin levels remained constant over a fermentation without starvation period: about 19 mg l‐1 diacetyl and 130 mg l‐1 acetoin were produced after utilization of 8.8 mM citrate. When fermentation products were discarded from the medium before starvation, diacetyl and acetoin levels reached 30 mg l‐1 and 240 mg l‐1, respectively.When the cells were allowed to rest on an isotonic diluent, citrate uptake rate slowed down, but the diacetyl plus acetoin yield remained higher since the cells accumulated as much acetoin (120 mg l‐1) and more diacetyl (50 mg l‐1). Peak production of diacetyl still coincided with citrate exhaustion whereas a delay in acetoin production was observed.
Activity of mutagens in the fungus Gibberella fujikuroi
Authors: R.  , Brückner B. , Blechschmidt D. , Fischer W. 
Published: February 2007

AbstractThe efficacy of a number of mutagens was examined for Gibberella fujikuroi. Nitrosoguanidine (MNNG) was the most effective mutagen inducing mainly morphological and pigment mutants. X‐ray produced small mutagenic effect. After UV‐irradiation pigment mutants developed for the most part and a combination of UV‐ and x‐ray‐irradiation mainly influenced the growth rate. A combination of UV‐irradiation with MNNG elicited the highest number of mutants with increased GA3 production.
The Streptomyces aureofaciens plasmid pIMB R8 and its use for shuttle vector construction
Authors: Godány Andrej , Lacová Bibiana , Zelinka Jan 
Published: February 2007

AbstractThe cryptic low copy plasmid designated as pIMB R8 was isolated from an industrial strain of the chlortetracycline producer Streptomyces aureofaciens R8/26. Using restriction endonucleases the pIMB R8 plasmid was characterized to have 15 kb. Subcloning of the Bam HI fragments of pIMB R8 into replication probe vector resulted in the identification of the replication part. The 0.7 kb Bc/I – Bg/I fragment is sufficient for normal replication, but produces about fourty times high plasmid copy numbers than the original pIMB R8. Using the replication part of pIMB R8 we constructed several shuttle cloning vectors for the E. coli‐streptomycete system.
Some factors affecting bioconversion of whole bagasse into fungal biomass
Authors: Nigam Poonam , Prabhu K. A. 
Published: February 2007

AbstractTwo isolated basidiomycetes mould cultures Polyporus BH1 and Polyporus BW1 and two standard white rot fungal cultures Pleurotus ostreatus and Polyporus versicolor were cultivated under submerged conditions on whole (untreated) bagasse for protein production. Some factors promoting better bioconversion were studied and selected. NORKRAN's medium at pH 5.0 with 1.0% bagasse of 80 mesh particle size using an appropriate quantity of inoculum, supplementing medium with an amino acid, without addition of any vitamin, etc. gave best results.
Distribution of three lysine‐catabolizing enzymes in various yeast species
Authors: Hammer Thomas , Bode Rüdiger , Schmidt Heike , Birnbaum Dieter 
Published: February 2007

Abstract28 yeast strains comprising a number of genera and species have been studied with respect to their ability to use l‐lysine as carbon or nitrogen source. Based on the utilization of this amino acid we could separate the yeasts into 3 groups. Enzymatic investigations demonstrate that yeasts can degrade l‐lysine by two distinct pathways. The first step of both ways was investigated and it was demonstrated that 3 enzymes, acetyl‐CoA: l‐lysine N‐acetyltransferase, l‐lysine α‐aminotransferase, l‐lysine α‐dehydrogenase, are able to catalyze the initial reaction. In 9 yeast strains the acetyltransferase was found. In 21 strains the aminotransferase and in 2 species the dehydrogenase could be detected. The enzyme formation could be enhanced in cells grown in the presence of l‐lysine as sole carbon and/or as sole nitrogen source.
Biosynthesis of tentoxin and dihydrotentoxin via protein turnover by Alternaria alternata
Authors: Liebermann B. , Schuffenhauer S. , Ihn W. 
Published: February 2007

AbstractBy shift experiments after labelling mycelium with d‐glucose‐U‐14C, l‐leucine‐U‐14C or Na15NO3, it was possible to demonstrate that in the biosynthesis of cyclic tetrapeptides during the idiophase, Alternaria alternata uses mycelium compounds produced and stored up in the trophophase. The participation of this protein turnover in the biosynthesis of tentoxin and dihydrotentoxin is very high, and differences are demonstrable concerning the single amino acids. If exogenous amino acids are available the fungus is also able to use them for the formation of the secondary products, in the early idiophase the highest incorporation rate was obtained.
Nachweis einer Fructokinase und ihre Bedeutung für den Stoffwechsel von Pseudomonas syringae pv. phaseolicola
Authors: Sauerstein J. , Schade R. , Emde J. , Reuter G. 
Published: February 2007

AbstractThe plant pathogenic Pseudomonas syringae pv. phaseolicola possesses a fructokinase which is epigenetically regulated. The kM values for fructose and ATP are 0.56 and 0.53 mM, respectively. About 23% of the activity observed with ATP was obtained with equimolar amounts of ITP. CTP, GTP, UTP, PEP and acetl‐P were ineffective, Fructokinase is responsible for the conversion of fructose to fructose‐6‐phosphate. In this way,. fructose, which is formed intracellulary during the growth in a sucrose or mannose containing medium, can be metabvolized via fructose‐6‐phosphate.
Host‐controlled modification and restriction as a criterion of evaluating the therapeutical potential of Pseudomonas phage
Authors: Gachechiladze K. K. , Balardshishvili N. S. , Adamia R. S. , Chanishvili T. G. , Krüger D. H. 
Published: February 2007

AbstractThe recently isolated phages ØST3 and ØST1 were compared as to their lysis behaviour in about 100 different P. aeruginosa strains. The growth of ØST3 varies greatly in different host strains. We demonstrated one case of “non‐classical”, host‐dependent modification and restriction. Here the capability to adsorb, and consequently to reproduce in a given host strain differs, depending on which modification the phage aquired in its former host. — The DNA‐containing phage ØST1 displays stable lysis properties in the majority of the host strains. This makes ØST1 a candidate for therapeutic phage preparations. One of the reasons for stable lysis properties is the apparent selection against recognition sites of restriction enzymes in its genome.
Steric course of the N‐methylation in the biosynthesis of ergot alkaloids by Claviceps purpurea
Authors: Gröger Detlef , Gröger Lisa , D'Amico Derin , He Min‐Xia , Floss Heinz G. 
Published: February 2007

AbstractUsing the chiral methyl group methodology, the methylation step in the biosynthesis of ergot alkaloids catalyzed by the enzyme AdoMet:dimethylallyltryptophan N‐methyltransferase was found to proceed with net inversion of methyl group configuration. The enzyme thus conforms to the majority of methyltransferases studied which mediate a direct SN2 transfer of the methyl group from AdoMet2) to the acceptor nucleophile in a ternary enzyme substrate complex.
Genetic recombination in Streptomyces michiganensis DSM 40 015 revealed three genes responsible for the formation of melanin
Authors: Held Thomas , Kutzner Hans J. 
Published: February 2007

AbstractBy UV and NTG mutagenesis numerous auxotrophic, antibiotic‐resistant and melanin‐negative mutants were isolated from Streptomyces michiganensis DSM 40 015 which proved to possess a efficient photoreactivation system. Using a mel− test strain with three auxotrophic markers and a antibiotic resistance for crosses with numerous prototrophic mel− strains three classes of mutants (melA, melB and melC) could be found. This classification was further supported by a series of crosses. The melC locus seemed to correspond to the melC locus of S. glaucescens which contains the tyrosinase structural gene.
Mechanistic studies of two amino acid racemases of broad substrate specificity from Pseudomonas striata and Aeromonas caviae
Authors: Reynolds Kevin , Martin Jennifer , Shen Shu‐Jane , Esaki Nobuyoshi , Soda Kenji , Floss Heinz G. 
Published: February 2007

AbstractThe conversion of l‐[α‐2H]alanine in H2O and unlabeled l‐alanine in 2H2O into d‐alanine, under nearly irreversible conditions, with the amino acid racemase from Pseudomonas striata showed significant internal transfer of the α‐hydrogen. This result has been interpreted as being indicative of a single base mechanism for the racemization.The relative rates of deuterium incorporation into unlabeled d‐ and l‐methionine by the two amino acid racemases of broad substrate specificity from P. striata and Aeromonas caviae, were measured in 2H2O. The results showed a markedly different pattern, dependent upon the configuration of the initial substrate; with d‐methionine as substrate deuterium is incorporated into both enantiomers at approximately the same rate, but with l‐methionine as substrate deuterium is incorporated considerably faster into the d than the l enantiomer. These results argue against a single base mechanism of racemization for these enzymes and are best rationalized in terms of a double base model where only one of the bases undergoes proton (deuterium) exchange with the solvent while the amino acid is enzyme‐bound. The interpretation of the earlier experiment needs to be considered in light of these results.
Reinigung und Charakterisierung von cAMP‐abhängigen Proteinkinasen bei Hefen in einem Saccharomyces cerevisiae Wildstamm und ausgewählten Mutanten des cAMP‐Stoffwechsels
Authors: Sachse O. , Jelen H. 
Published: February 2007

AbstractProtein kinases represent a diverse family of enzymes that play a critical role in regulation. Among nearly 100 known protein kinases, the cAMP‐dependent enzyme is best understood biochemically. Unlike other protein kinases, cAMP‐dependent protein kinase consists of two different types of subunits that dissociate, a regulatory subunit (R), which is the receptor for cAMP, and a catalytic subunit (C). In the absence of cAMP, the enzyme exists as an inactive tetramer, R2C2. The binding of intracellular cAMP to the R subunit decreases the affinity of the R subunit for the C subunit by approximately four orders of magnitude and, under physiological conditions, leads to dissociation of the holoenzyme into R2(cAMP)4 dimer and two free C subunits that are catalytically active. Mutants of the cAMP metabolism, adenylate cyclase and cell cycle mutants, provided further information about protein synthesis and cellular growth in Saccharomyces cerevisiae. The purified protein kinases were divided into different types according to their elution profiles from the DEAE‐cellulose matrix. Two types of cAMP‐dependent and two types of cAMP‐independent protein kinases were isolated from the wild strain. Differences in the activities of the kinases in the mutants showed a close relationship to the locus of the respective mutations in the cell‐cycle. Some properties of the protein kinases are discussed with respect to individual mutations.
On the role of 26‐deoxylaidlomycin in laidlomycin biosynthesis
Authors: Gräfe U. , Stengel C. 
Published: February 2007

Abstract3H‐26‐deoxylaidlomycin (I) was fed to growing cultures of Streptoverticillium olivoreticuli IMET 43782 producing both I and laidlomycin (II). The incorporation of labelled I into laidlomycin II was neglible showing a role of I as precursor of II to be at variance. Otherwise, a measurable conversion was achieved by the use of sonicated 48 hrs mycelium suggesting that final oxidation of I to II could be mediated by a compartmentized oxidoreductase.
Production of xylanase by Verticillium albo‐atrum in the presence of polymeric substances
Authors: Bahkali A. H. 
Published: February 2007

AbstractThe production of xylanase in the presence of various polymeric substrates was studied. Among the polymeric substrates, xylan was the best inducer of xylanase by V. albo‐atrum. Other cellulolytic enzymes such as glucanase and β‐glucosidase were synthesized in smaller quantities. The process of degradation indicated that xylanase behaved as typical endo enzyme causing first production of high mol. wt. products. Studies on xylan medium indicated that V. albo‐atrum produced at least three enzymes which degrade xylan.
Reduction of saturated derivatives of testosterone by a strain of Aphanocladium album
Authors: Dmochowska‐Gladysz Jadwiga 
Published: February 2007

AbstractA strain of Aphanocladium album was found to reduce carbonyl group at C‐3 in 5α‐ and 5β‐dihydroderivatives of testosterone and androstendione. Stereochemistry of this reduction depends on the geometry of ring junction as well as on the presence of substituents (CH3 at C‐4, OAc at C‐17, or OH at C‐19). The simultaneous presence of both CH3 at C‐4 and OAc at C‐17 inhibits the reduction totally in both 5α‐ and 5β‐isomer. The substrates containing a carbonyl group at C‐17 were reduced to 17β‐alcohol.
15α‐Hydroxylation of 13‐ethyl‐gon‐4‐ene‐3,17‐dione using a hyphal fungus immobilized in calcium alginate gel beads
Authors: Schlosser D. , Schmauder H.‐P. 
Published: February 2007

AbstractCalcium alginate‐entrapped mycelium of Penicillium raistrickii i 477 was used for the 15α‐hydroxylation of 13‐ethyl‐gon‐4‐ene‐3,17‐dione. The system was tested in 10 batches during 40 days of operation, the catalytic activity could be completely regenerated by incubation in a nutrient medium between several batches.
Thermophilic actinomycetes associated with agro‐environment of Punjab State (India)
Authors: Singh S. , Sandhu M. S. , Singh M. , Harchand R. K. 
Published: February 2007

AbstractThermophilic actinomycetes (TAs) are unique high temperature aerobic bacteria which belong to the group actinomycetes. While working on hypersensitivity pneumonitis (HP), an immunological disorder, resulting from the inhalation of spores of thermophilic actinomycetes, it was considered worthwhile to record their occurrence in the environment of Punjab. Thermophilic actinomycetes isolated by spread plate method from nine different substrates of the Punjab environment were identified as 8 different species. Atmospheric occurence of TAs was detected by exposing Petri dishes containing soy agar medium which were exposed in six different environments of the state. Seven thermophilic species were recorded. Thermoactinomyces vulgaris was the predominant species with 87.5, 87.1, and 100% prevalence in the soil, natural manure and the wheat field, respectively. The study is the first report of its kind from this region.
Interactions of Mycobacterium fortuitum with solid sterol substrate particles
Authors: Atrat P. , Hösel P. , Richter W. , Meyer H. W. , Hörhold C. 
Published: February 2007

AbstractMycobacterium fortuitum NRRL B‐8119 transformes sterols into 9 alpha‐hydroxy‐androsta‐4‐ene‐3,17‐dione (9OH‐AD) at high efficieny. Cells strongly aggregate to the surface of the sterol particles forming stable agglomerates (“substrate immobilized cells”). Substrate uptake and product formation were studied as function of the size of the sterol particles. Using particle sizes comparable with the size of the mycobacterial cells (> 5μm) highest rates were found for both the substrate uptake and the product formation. After mechanical reinforcement of the contact between mycobacterial cells and the sterol substrate by co‐grinding of the components, a significantly increased product formation was observed. Associated cells and cell‐sterol agglomerates were investigated by freeze‐fracture electron microscopy. The micrographs obtained demonstrate that cells of M. fortuitum are growing into the sterol microcrystallite. The uptake of the sterol substrate is assumed to take place via direct contact between cells and the substrate particles. To understand the transport mechanism a model is proposed that includes a flexible multicomponent mesophase (FMCM) which is placed between cells and particles and which mediates the sterol uptake. The putative FMCM is assumed to be composed of mycobacterial glycolipids, extracellular biolipids, synthetical detergents, sterol and water.
Comparative study of external and internal β‐glucosidases and glucoamylase of Arxula adeninivorans
Authors: Büttner Roland , Bode RÜDiger , Birnbaum Dieter 
Published: February 2007

AbstractProperties of external and internal β‐glucosidases and glucoamylase of Arxula ademinivorans were compared. For the purification of enzymes, the C‐catabolite derepression mutant SBUB 724/41 was used. The following Km‐values for β‐glucosidases with cellobiose as substrate were measured: 14.3 mm (external β‐glucosidase I), 4.1 mm, Ixternal β‐glucosidase I), 5.0 mm (internal β‐glucosidase II), 3.0 mm (external β‐glucosidase II). The Km‐values of the glucoamylase for maltose were 4.6 mm (internal enzyme), 11.1 mm (external enzyme), and for starch 0.32 g/1 and 1.2 g/1, respectively.Both external β‐glucosidases showed a relatively sharp pH‐optimum in a range from 4.5 to 5.5 while that of internal enzymes was between 5.5 and 6.0. No differences were obtained between pH‐optima (4.5‐5.5) of internal and external glucoamylase. The temperature optimum values of internal β‐glucosidase I (40°C) and of internal β‐glucosidase II (50°C) were remarbably low compared with those of the external β‐glucosidases (60–63°C) and both glucoamylases (60°C).Molecular mass of 570 kD for the external and of 290 kd for the internal β‐glucosidase I, on the one hand, and of 525 kD and 180 kD for the internal β‐glucosidase II on the other hand were determined. The external gucoamylase consists of two subunits with a molecular mass of 110 kD. After deglycosylation a molecular mass of 76 kD was measured, indicating a carbohydrate content of 30%. whereas for the internal enzyme, a molecular mass of 95 kD was estimated.
Mycoflora associated with five species of freshwater leeches
Authors: Khallil Abdel‐Raouf M. , Bagy M. M. K. , El‐Shimy N. A. 
Published: February 2007

AbstractTwenty‐two species belonging to 11 genera of zoosporic fungi were collected from 10 freshwater sites and from five species of leeches on sesame and hemp seeds, maize grains and Pinus pollen grains as baits at 22°C. Dictyuchus, Achlya, Pythium, Allomyces and Saprolegnia were the most common genera. The highest population of zoosporic fungi was estimated from Batracobdelloides tricarinata, the lowest from Barbronia assiuti.In addition fifty‐three species and 1 variety representing 23 terrestrial fungal genera were identified on glucose (17 genera and 41 species) and cellulose (20 genera and 34 species + 1 variety) Czapek's Dox agar at 28°C. The most common species on the two media were Aspergillus niger, A. fumigatus, A. flavus, Trichoderma harzianum, Gibberella fujikuroi and Penicillium chrysogenum. Some fungi were common only on cellulose agar medium such as Botryotrichum atrogriseum, Chaetomium bostrychodes, Dactylella alaskana and Drechslera halodes.Batracobdelloides tricarinata was the richest with terrestrial fungi whereas Salifa delicata was the poorest.Five leech species, namely Alboglossiphonia polypompholyx, Batracobdelloides tricarinata, Helobdella conifera, Barbronia assiuti and Salifa delicata were used during this investigation.