bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of cyanate on nitrate reduction by Rhizobium meliloti SU47
Authors: Roy Nupur , Chowdhury Aju , Roy S. , Chakrabartty P. K. 
Published: February 2007

AbstractEffect of cyanate on nitrate reduction by Rhizobium meliloti SU47 was studied. In the presence of cyanate assimilatory nitrate reduction activity appeared in the culture after a long lag and a conspicuously low level of nitrite was accumulated. Dissimilatory nitrate reduction activity was low in the intact cells precultured in KCNO of KNO3 as compared to that in the control. Dissimilatory nitrate reductase activity in the extracts of cells precultured in KCNO was also compared to be low. In the extracts, dissimilatory nitrate reductase activity assayed with increasing concentrations of KCNO confirmed that KCNO acts as an inhibitor of the enzyme.
L‐Lysine α‐oxidase from Trichoderma viride i4. Purification and characterization
Authors: Weber Ekkehard , Tonder Karin , Reinbothe Christiane , Unverhau Kerstin , Weide Heinz , Aurich Harald 
Published: February 2007

AbstractA L‐lysine α‐oxidase (LOD) has been purified to homogeneity in a two‐step procedure with 300‐fold enrichment and 60% recovery from the culture extract of Trichoderma viride i4. The enzyme catalyzes the reaction between L‐lysine and molecular oxygen forming 2‐oxo‐6‐aminocaproate, ammonia and hydrogen peroxide. Numerous substrates have been tested. The Km value for L‐lysine was found to be 0.026 mM. Its apparent molecular mass is 110000 Da when determined by gel filtration on Sephadex G‐200, the estimated molecular weight of the subunits being 55000 Da in the SDS‐PAGE. The enzyme is a glycoprotein and shows absorption maxima at 276, 386 and 463 nm. It was found to contain 1 mol of FAD per subunit. The coenzyme is bound non‐covalently. Its isoelectric point is at pH 4.3. The enzyme is stable at extreme pH values, at relatively high temperatures and in diluted hydrogen peroxide.The enzyme described here differs from two other known L‐lysine oxidases previously characterized with regard to its amino acid composition and its substrate specificity.
Lipid variation at different temperatures on two species of Xenorhabdus
Authors: Maheshwari D. K. , Nishimura Y. 
Published: February 2007

AbstractThis paper describes the lipid variation of Xenorhabdus nematophilus N24 and Xenorhabdus luminescens HP88 grown at different temperatures (25 °C, 18 °C and 5 °C). In both strains phosphatidylethanolamine was identified to be the major phospholipid accounting about 80% of lipid phosphorus. In X. luminescens HP88 a significant portion of cardiolipidin was found. The major fatty acid found was palmitic acid (C16:0), palmitoleic acid (C16:1) and oleic acid (C18:1). However, lauric acid (C12:0), myristic acid (C14:0), C17 cyclopropane acid (C17‐cy) and stearic acid (C18:0) were also detected. Decreasing growth temperatures from 25 °C to 18 °C was accompanied by increase in percentage of unsaturated fatty acid C16:1 at the expense of saturated fatty acids like C16:0, C18:0 and C17‐cy. Further decrease in temperature to 5 °C led to decline in C17‐cy in favour of C16:1 in X. nematophilus N24 but it could hardly get any change in fatty acid composition of X. luminescens HP88.
Physiological characterization of chlorate‐resistant mutants of the cyanobacterium Spirulina major
Authors: Singh Y. , Kumar H. D. 
Published: February 2007

AbstractChlorate‐resistant (ChlR)mutants SM11 and SM25 of the cyanobacterium Spirulina major were produced by N‐methyl‐N'‐nitro‐N‐nitrosoguanidine (NTG)1) mutagenesis. Strain SM11 showed nitrate reductase (NR) and glutamine synthetase (GS) activities equal to the SMP (parent) whereas SM25 had about 45% NR and 78% GS as compared to SMP. However, the uptake of nitrate or ammonia was almost equal in SMP, SM11 and SM25. ChlR strains differed physiologically between themselves, SM11 being blocked in uptake system of chlorate (Chl up−) and was not defective in NR or GS, while SM25 showed chlorate uptake (Chl up−) and was defective in NR (NRdef) and GS (GSdef). Thus strain SM11 resembles SMP except that the latter is chlorate sensitive. This is the first report of defective NR in any filamentous, non‐heterocystous, non‐nitrogen fixing cyanobacterium. Defective chlorate uptake not accompanied by defective NO uptake has also been observed in strain SM11.
Mutations affecting gluconate catabolism in Escherichia coli. Genetic mapping of loci for the low affinity transport and the thermoresistant gluconokinase
Authors: De Rekarte Usua D. , Cortés Marieen , Porco Antonietta , Niño Gustavo , Istúriz Tomás 
Published: February 2007

AbstractThe isolation and properties of strains of Escherichia coli carrying mutations affecting either the low affinity transport for gluconate (gene gntU) or the thermoresistant gluconokinase (gene gntK) are described. A lesion of each type was genetically characterized by transduction experiments. Both mutations mapped in the asd region, and the order was malA‐glpD‐asd‐gntU‐gntK, with the last two markers at about min 75.78 and 75.86 on the map, respectively. Mutations altering specifically gntU have not been previously reported.
Effect of inhibitors of cell envelope synthesis on β‐sitosterol side chain degradation by Mycobacterium sp. NRRL MB 3683
Authors: Sedlaczek Leon , Górmiński Bernard Marcin , Lisowska Katarzyna 
Published: February 2007

AbstractThe role of the lipid bilayer and the peptidoglycan of the mycobacterial cell wall in the permeation of β‐sitosterol into the cell and its transformation to androst‐1‐ene‐3,17‐dione (AD) and androsta‐1,4‐diene‐3,17‐dione (ADD) was studied. Specific inhibitors were used at concentrations affecting the biosynthesis of the assumed target structures, but causing only partial cell growth inhibition or exerting no effect on growth. m‐Fluorophenylalanine and dl‐norleucine which are known to disorganize the biosynthesis of amphipatic components of the outer layer of the lipid bilayer, used at concentrations 250 μg/ml and 400 μg/ml, respectively, increased the formation rate of AD + ADD from 0.3 (control) to 0.7 and 0.8 mg products/g dry weight/h. The disorganization of the underlying mycolyl‐arabinogalactan structure by the action of ethambutol at the concentration 40 μg/ml, at which the cell growth was apparently not affected, caused the decrease of the product formation from 135 mg/1 to 70 mg/1. In the presence of isoniazid (350 μg/ml) only trace amounts of AD accumulated during 48 hours of transformation indicating much lower activity than that of the intact cells. The most effective among the tested inhibitors of peptidoglycan synthesis were glycine (15 mg/ml) and vancomycin (150 μg/ml) which enhanced the transformation activity of the treated cells nearly three times. Increased transformation rate was also obtained by the action of colistin at concentrations ranging from 10 μg/ml to 15 μg/ml.
Solid‐state (substrate) fermentation systems and their applications in biotechnology
Authors: Nigam Poonam , Singh Dalel 
Published: February 2007

AbstractSolid‐state fermentations have attracted renewed interest and attention from researchers due to recent developments in the field of biotechnology. In this article some aspects of solid‐state cultivations have been reviewed, including characteristics of substrates and microorganisms used for various endproducts.
Effect of increased ppGpp concentration on DNA replication of different replicons in Escherichia coli
Authors: Herman Anna , Wèrzyn Grzegorz 
Published: February 2007

AbstractThe plasmids harbouring the relA gene under an inducible promoter allowed us to increase the guanosine 5′‐diphosphate‐3′‐diphosphate (ppGpp) concentration in Escherichia coli cells without any starvation and thus, to directly investigate the effect of ppGpp on DNA replication. We studied all types of replicons which were investigated previously in amino acid‐starved bacteria and found that ColE1, oriC, λ plasmid and pSC101 but not RK2 replicons are sensitive to high ppGpp level. To our knowledge, this paper presents the first direct evidence that replication of most, but not all, replicons is dependent on ppGpp concentration and thus, is under stringent control.
Selection of lysine‐excreting mutants from Aureobasidium pullulans
Authors: Wu Chengbin , Reed‐Hamer Beth , West Thomas P. 
Published: February 2007

AbstractA method to select lysine‐excreting mutants from the fungus Aureobasidium pullulans was devised. This method involved the use of bacterial auxotroph indicator solid medium where mutant colonies were detected by their ability to support the satellite growth of an Escherichia coli lysine auxotrophic strain in the medium. Utilizing this procedure and a lysine bioassay, two mutants were identified that were capable of producing approximately double the concentration of lysine in the culture medium relative to their parent strain.
A phycoerythrin‐lacking mutant induced by DCMU in photoheterotrophically grown Nostoc linckia
Authors: Bastia A. K. , Adhikary S. P. 
Published: February 2007

AbstractA blue‐green strain showing loss of phycoeryhtrin pigment was obtained from the 15 mM fructose and 10−5 M DCMU [3‐(3,4‐dichlorophenyl),1,1‐dimethyl urea] supplemented photoheterotrophic culture of the blackish‐brown rice‐field cyanobacterium Nostoc linckia. Absence of phycoerythrin in the mutant strain was ascertained from the whole cell absorption spectra and spectra of water soluble pigments. Quantitative estimation of photosynthetic pigments of the parent and mutant strain showed that increase in the chlorophyll and phycocyanin content took place in the mutant with a total loss of phycoerythrin. Subculturing under low and high light intensities brought no change in the mutant. The mutant strain grew well, synthesized high amounts of chlorophyll and phycocyanin and possessed higher nitrogen‐fixing capacity in comparison to the parent material.
Microbiological survey of a South African poultry processing plant
Authors: Geornaras Ifigenia , De Jesus Amelia , Van Zyl Elsabé , Von Holy Alexander 
Published: February 2007

AbstractBacterial populations associated with poultry processing were determined on neck skin samples, equipment surfaces and environmental samples by replicate surveys. Aerobic plate counts, Enterobacteriaceae counts and Pseudomonas counts were performed by standard procedures and the prevalence of Listeria, presumptive Salmonella and Staphylococcus aureus determined. Statistically significant (P < 0.05) increases in counts of all types of bacteria were obtained on product samples as a result of processing. Although bacterial counts on neck skin samples decreased by 0.3 to 0.4 log CFU g−1 after spray washing of carcasses, subsequent spinchilling and packaging of whole carcasses resulted in 0.7 to 1.2 log CFU g−1 increases. Bacterial numbers on equipment surfaces, however, decreased significantly from the „dirty”︁ to the „clean”︁ areas of the abattoir. Transport cages, „rubber fingers”︁, defeathering curtains, shackles and conveyor belts repeatedly showed aerobic plate counts in excess of 5.0 log CFU 25 cm−2. Aerobic plate counts of scald tank and spinchiller water were 2 log CFU ml−1 higher than those of potable water samples. Bacterial numbers of the air in the „dirty”︁ area were higher than those of the „clean”︁ area. Listeria, presumptive Salmonella and Staphylococcus aureus were isolated from 27.6, 51.7 and 24.1% of all product samples, respectively, and Listeria and Staphylococcus aureus were also isolated from selected equipment surfaces.
Phenol and cresol metabolism in Bacillus pumilus isolated from contaminated groundwater
Authors: Günther K. , Schlosser D. , Fritsche W. 
Published: February 2007

AbstractFrom an aquifier contaminated with phenolic compounds seven bacterial strains able to grow on phenol and several mono‐ and disubstituted alkylphenols as sole source of carbon and energy were isolated. Five isolates belong to the genus Pseudomonas, two to the genus Bacillus. The isolate most active in utilization of the applied xenobiotics was identified as Bacillus pumilus and used for the investigation of the degradation pathways in liquid cultures. Cells of this strain precultured on phenol were able to utilize para‐cresol as sole carbon source via the oxidation of the methylsubstituent and intradiol ring cleavage of the resulting protocatechuic acid, whereas an intradiol ring fission of the intermediate 4‐methylcatechol led to 4‐methylmuconolactone as dead end‐product. Cells precultured on meta‐ and ortho‐cresol were able to utilize the respective compounds as sole carbon sources via 3‐methylcatechol, which induced the following extradiol ring fission pathway. Cells precultured on phenol were able to cooxidize meta‐ as well as ortho‐cresol to 3‐methylcatechol, which was cleaved via an intradiol ring fission, finally leading to the dead end‐product 2‐methylmuconolactone.
Effects of NaCl stress on the growth dynamics and protein content of Rhizobium DDSS 69
Authors: Natarajan K. , Kishore L. , Babu C. R. 
Published: February 2007

AbstractSodium chloride stress results in an increased lag phase of Rhizobium culture at inhibitory concentrations without affecting either the mean generation time (MGT) or the duration of log period. Irrespective of the phase of addition of NaCl the cells exhibited a ‘critical’ phase. Osmoprotectants do decrease the period of ‘critical’ phase but only if added prior to or along with the addition of NaCl. There is a progressive decrease in the protein content of cells grown under NaCl stress and betaine has no effect on the protein content.
β‐amalyse production by immobilized cells of Bacillus megaterium B6
Authors: Ray Rina Rani , Jana Subhas Chandra , Nanda Geeta 
Published: February 2007

AbstractWhole cells of Bacillus megaterium B6 were immobilized by ionotropic, thermal gelation and polymerization of which ionotropic gelation was found to be most suitable process for α‐amylase production. Strontium was proved to be the best divalent cation for alginate entrapment of cell in terms of enzyme production and reusability of the cells.
Pulse feeding with nitrate and phosphate in relation to tissue composition and nutrient uptake by some macroalgae from the Red Sea at Ghardaqa (Egypt)
Authors: Aisha Kh. Abou , Shabana Effat F. , El‐Abyad M. S. , Kobbia I. A. , Schanz F. 
Published: February 2007

AbstractThis investigation aimed at determining the effects of experimental enrichment with either N or P or both elements on the tissue nutrient levels, and on the internal N: P molar ratios of three macroalgal species collected in the vicinity of Ghardaqa, Red Sea, EgyptThe results obtained showed that the rates of nutrient (nitrate and phosphate) uptake were highly species dependent. Uptake rates of both nutrients were significantly higher forCodiumthan for eitherDictyotaorGalaxaura.For the three algae, uptake, except nitrate byGalaxaura, was rapid during the first 6 h of immersion and declined during the rest of the experiment. The observed increases in N levels after 6 h of enrichment decreased sharply after 24 h of enrichment. The fluctuations in tissue‐N were accompanied by fluctuations in protein levels. Total carbohydrate content of the three macroalgae was decreased in seawater treatments enriched with either N or N+P for 24 h compared with non‐enriched plants or plants enriched with P only. For the three macroalgae, enrichment with P resulted in consistent increases in tissue‐P levels over the experimental period. The changes in the N:P ratios of the three plants were significantly correlated with the increases in tissue ‐P as compared to tissue ‐N.G. rugosaappeared to be the most strongly nutrient ‐ limited of the three algal species studied andD. dichotomawas the least.
Kinetic studies on the yeastPhaffia rhodozyma
Authors: Acheampong Edward A. , Martin Antonio M. 
Published: February 2007

AbstractThe yeastPhaffia rhodozyma, a promising microbial producer of the carotenoid astaxanthin, was cultivated in batch and continuous processes in an agitated and aerated fermenter using an acid peat extract ‐ based culture medium. For the accelerated growth phase, the mean specific growth rate and doubling time were found to be 0.038 h−1, and 18.24 hours, respectively. The production of astaxanthin was found to be basically growth associated, the maximum concentrations of the pigment produced in batch culture and continuous cultivation being similar.
Ultrastructure of circulating immune complexes isolated from the blood plasma of patients suffering from infectious diseases
Authors: Didenko L. V. , Andreevskaya S. G. , Konstantinova N. D. , Buchwalow I. B. 
Published: February 2007

AbstractAn original procedure which permits to isolate circulating immune complexes (CIC) from the blood plasma in a form of a dense pellet was developed. This procedure was applied for the ultrastructural analysis of CIC isolated from blood of healthy blood donors and patients suffering from Yersinia enterocolitica (YE) and Yersinia pseudotuberculosis (YP) infections. The here reported method of CIC isolation from blood plasma permitted to visualize CIC electronmicroscopically as amorphous masses of low, middle, and high electron density with inclusions of cell debris. In contrast to CIC of healthy blood donors, CIC of infected patients contained various bacteria and fungiformic structures. For the first time, this method made possible an ultrastructural demonstration of bacterial destruction outside of phagocytes in vivo. This method also permits to visualize and identify bacteria in cases of lingering forms of infection when hemoculture tests fail. Therefore, electronmicroscopic examination of CIC preparations from the blood plasma might be a very informative indicator of bacteriemia in the course of an infection process and serve as an indicator of therapeutic effects. In lingering forms of an infection process, ultrastructural analysis of CIC preparations can be of prognostic value and serve as an indicator of therapeutic effects. This method might be also advantageous as an additional test for the exposure of latent bacterial persistence in diagnostically complicated cases.
Catabolite repression of inductive polygalacturonase synthesis in Penicillium expansum by sucrose
Authors: Piccoli‐Valle Roberta Hilsdorf , Baracat‐Pereira Maria Cristina , Silva Daison Olzany 
Published: February 2007

AbstractPolygalacturonase (PG) synthesis by the fungus Penicillium expansum in the presence of a combination of pectin and sucrose corresponding to 0.3% of the substrate was repressed more intensely by increasing sucrose concentrations and decreasing pectin concentrations. PG synthesis was partially repressed when sucrose was added 6 or 12 h after the beginning of culture and fully repressed when sucrose was added at the beginning of culture. Tests with actidione indicated that repression by sucrose occurs at the transcription level. We suggest that an accumulation of messenger RNA occurred when the fungus was cultured for 36 h in 0.3% pectin and actidione since, after being washed and reincubated in actidione‐free medium in the presence of the repressor, the fungus synthesized PG up to 54 h of culture, when a reduction in accumulated messenger RNA and PG synthesis occurred. Repression by sucrose was reversible since the fungus started synthesizing PG again in the absence of the repressor and in the presence of the inducer.
The properties of the multicopy suppressor of the ogdl mutation in yeast
Authors: Gbelská Yvetta , Mockovčiaková Daniela , Timko Jozef , Šubík Július 
Published: February 2007

AbstractThe 8.1 kb chromosomal fragment partially suppressing the ogdl mutation in Saccharomyces cerevisiae has been cloned. The molecular analysis revealed that its suppressor gene codes for a natural glutamine tRNACAG and maps on chromosome XIII in the upstream region of the URA10 gene. The multicopy plasmids containing this tRNA gene also suppressed the standard trpl‐l amber mutation and conferred the sensitivity of yeast cells to paromomycin and increased temperature.
Effect of different carbon sources on growth and glutamic acid fermentation by Brevibacterium sp.
Authors: Nampoothiri K. Madhavan , Pandey Ashok 
Published: February 2007

AbstractExperiments were carried out to find the efficiency of Brevibacterium sp. to utilize different carbon sources (glucose, fructose, sucrose, maltose, lactose, xylose and starch) for its growth and for the production of glutamic acid. Except starch, all the carbon sources supported the growth of the culture, which showed a preferential choice of growth and activity when grown on glucose as sole carbon source. Mixed substrate fermentation did not improve the yield of amino acid. Maximum glutamic acid yields (6.86 mg/ml) were obtained when 2% glucose medium was fermented under optimized conditions for 48 h.
Studies on rifamycin production by Amycolatopsis mediterranei cells immobilized on glass wool
Authors: Abu‐Shady Mohamed R. , El‐Diwany Ahmed I. , Farid Mohamed A. , El‐Enshasy Hesham A. 
Published: February 2007

AbstractCells of Amycolatopsis mediterranei CBS 42575 were immobilized on glass wool for the production of rifamycins B and SV. Glass wool (CORNING type) of 8 microns in diameter has a better entrapment capacity for microbial cells of microorganism than the other types of glass wool used. The most suitable amount of glass wool was 0.8 g/50 ml. The best initial cell concentration used as inoculum was 40 mg cells/50 ml. Repeated batch production of rifamycins by immobilized cells on glass wool was carried out for 6 repeated batches. The results showed that reduction of batch time from 96 h to 48 h does not decrease rifamycin production by immobilized cells.
Salt‐ and pH‐dependent hemagglutination with Kasba virus, a member of the Palyam serogroup of the genus Orbivirus
Authors: Jusa E. R. , Inaba Y. 
Published: February 2007

AbstractKasba virus grown in BHK21‐WI2 cells was tested for hemagglutination (HA) with erythrocytes of a variety of species at 4°C, 25°C and 37°C. HA was observed at all temperatures with cattle, sheep and goat but not with swine, chicken, and goose erythrocytes. The HA was dependent on not only the NaCl concentration but also the pH of the diluent. The HA titer significantly improved by increasing the NaCl molarity to 0.6 M and standardizing pH to 7.5. The HA titer was 16‐ or 32‐fold higher in 0.4 M or 0.6 M solution than in 0.2 M solution of not only NaCl but also several other salts. The HA reaction was inhibited by specific antibody.
A rapid method for differentiation of Xanthomonas campestris pv. mangiferaeindicae from other Xanthomonads and mango phylloplane inhabitants
Authors: Sanders Gina M. , Korsten L. 
Published: February 2007

AbstractA rapid method for differentiation of Xanthomonas campestris pv. mangiferaeindicae from other Xanthomonads and phylloplane inhabitants is described. Several selective media were evaluated for selective enrichment of X. campestris pv. mangiferaeindicae from mango plants. Boost broth supplemented with cycloheximide, methyl violet and methyl green enhanced growth of epiphytic X. campestris pv. mangiferaeindicae but not other phylloplane organisms. The identity of X. campestris pv. mangiferaeindicae selectively enriched from mango plant material was confirmed with monoclonal antibodies in an Enzyme‐Linked Immunosorbent Assay. Preliminary field evaluations showed that selective enrichment and confirmation by ELISA could successfully detect latent infections of X. campestris pv. mangiferaeindicae in mango plants.