bluuebunny/crossref_metadata_2025_split huggingface dataset:
Process optimization for continuous ethanol fermentation by alginate‐immobilized cells of Saccharomyces cerevisiae HAU‐1
Authors: Yadav B. S. , Rani Usha , Dhamija S. S. , Nigam Poonam , Singh Dalel 
Published: February 2007

AbstractContinuous ethanol production by immobilized cells of Saccharomyces cerevisiae HAU‐1 has been studied using synthetic and molasses based medium in column reactors. Immobilization of 30% yeast cells biomass (wet) in 1.5% calcium alginate gel resulted in the production of 20.8 g · 1−1 · h−1 alcohol at a dilution rate of 0.36 h−1 with approximately 1/3rd volume of the column reactor packed with gel beads. Optimum diameter of the beads was found to be 3.5 mm for efficient fermentation. The size of the column reactor (length to diameter ratio) also affected the productivity and fermentation efficiency due to gas hold‐up and mass transfer effects. Molasses could also be fermented by this system but at a lower fermentation efficiency which could be improved, to some extent, by supplementation with nutrients.
Thermokinetic profile of the yeast Rhodotorula ferulica and its modification by tributyltin‐oxide (TBTO)
Authors: Pinto Ana Ferreira , Veiga Alexandra , Madeira‐Lopes A. 
Published: February 2007

AbstractThe temperature range of growth of Rhodotorula ferulica on vanillic acid shrank from 5.3–31.6 °C to 11.1–26.0 °C in the presence of TBTO (tributyltin‐oxide) at 23.4 μM (the maximum tolerated by the organism). However, it took just 5 μM of the drug to transform the thermokinetic profile from associative (cardinal temperatures: top = 27–28°C, tmin d = 29.5°C, tmax f = 32.5 °C, tmax i = 35 °C) into dissociative (tmin d = 34 °C, tmax = 30 °C), the specific growth rates decreasing by one order of magnitude. In the supraoptimal temperature range (when exponential growth concurred with thermal death) the yield coefficients decreased by 70% on vanillic acid, rather than on glucose. The results are consistent with the hypothesis that the target for TBTO in this yeast is different from the thermal death target.
15N‐uptake, influenced by UV‐B radiation, and pattern of amino‐acid pools during akinete germination in Anabaena variabilis (Cyanobacteria)
Authors: Fraune Wolfram , Döhler Günter 
Published: February 2007

AbstractIn order to obtain better information on the nitrogen supply during the early germination period of Anabaena resting cells (akinetes) the uptake of 15N‐nitrate and 15N‐ammonium and changes in the amino acid pools were studied. Additionally, the influence of a UV‐B‐dose on the nitrogen uptake in germinating akinetes was investigated.Results indicate: (1) Ammonium was finally incorporated during a 48‐hours period after initiation of germination to a similar degree as nitrate, but follows different kinetics. (2) UV‐B radiation (0.95 W m−2, 0.5 to 5 hours) applied at the beginning of this period, did not have any (15N‐nitrate) or only minor (15N‐ammonium) influence on the nitrogen uptake (% 15N enrichment determined 48 h after initiation of germination). When a comparable UV‐B load was applied at the end of the 48‐hours (pre‐)germination period, a varying effect on the 15N‐accumulation during a subsequent 48‐hours period could be noticed: Whereas the nitrate uptake again remained uninfluenced, increasing accumulation of 15N‐ammonium took place, corresponding to the increasing UV‐B dose. (3) Pool patterns of amino acids/amides are different in akinetes and filament cells (filaments show a relatively higher content in glutamate, glutamine, serine and lower in arginine, asparagine and lysine). (4) During the 48‐hours (pre‐)germination period a transient increase in the proportion of some amino acids/amides was established, but the drastic proportionate decrease in the content of asparagine and arginine during the first 6 to 12 hours after initiation of germination was the most conspicuous effect. This observation is discussed in connection with the nitrogen mobilisation from the cyanophycin storage of the cells.
Microbiological transformation of progesterone by some zoosporic fungi
Authors: Khallil A. M. , Mostafa M. Eman 
Published: February 2007

AbstractTwelve isolates of zoosporic fungi belonging to four species (three isolates each) of the genus Saprolegnia were tested for progesterone biotransformation. The three isolates tested of each of S. hypogyna and S. parasitica have the capacity to perform oxidative splitting of the side chain of progesterone with the formation of Δ4 androstene‐3,17 dione, testosterone and testololactone. All the isolates tested of S. diclina and S.furcata failed to transform progesterone molecule into another steroid derivative. The chromatographic resolution of the mixture products obtained when S. hypogyna (isolate No. 1008‐2) had acted on one gram progesterone revealed the presence of 15 % unchanged progesterone, 25% Δ4‐androstene‐3,17‐dione, 25% testosterone and 35% testololactone.
Physical and biochemical characterization of a competition and nodulation defective mutant of Azorhizobium caulinodans ORS571
Authors: Kishore L. , Natarajan K. , Babu C. R. 
Published: February 2007

AbstractThe competitive ability of Azorhizobium caulinodans strain ORS571 was assessed using induced mutagenesis, which resulted in isolation of two mutants that were either defective in symbiotic properties or in competition for nodulation of Sesbania rostrata. One of the mutants was non‐nodulating whereas the other one exhibited reduced competitiveness when inoculated along with the parent strain. Further characterization revealed that the non‐nodulating mutant exhibited altered protein and lipopolysaccharide (LPS) profiles and the absence of flagella.
Bacterial heavy metal‐tolerance — extreme resistance to nickel in Arthrobacter spp. strains
Authors: Margesin Rosa , Schinner Franz 
Published: February 2007

AbstractThe heavy metal‐resistant bacterial community of strongly polluted industrial areas was investigated. The bacterial tolerance levels to nickel, chromium and copper depended greatly on the pollution degree of sampling sites. Thirty‐six selected strains were tested on their multiple heavy metal resistance, most strains were resistant to high concentrations of nickel as well as of chromate. Remarkably, 4 plasmid‐containing strains with an extreme resistance to nickel (up to 20 mM) were Gram‐positive and identified as Arthrobacter spp. Nickel resistance is an induced mechanism in 3 strains and is constitutively expressed in one of the 4 strains; nickel resistance is influenced by temperature. This is the first description of extreme nickel resistance in Grampositive bacteria.
Studies on an amylolytic strain of Saccharomyces cerevisiae isolated from yam tuber
Authors: Olasupo N. A. , Teniola O. D. , Okosun R. , Omowaye A. , Olatope S. O. , Scott‐Emuakpor M. B. 
Published: February 2007

AbstractAn amylolytic yeast strain identified as Saccharomyces cerevisiae was isolated from yam tuber. Studies on the effect of physical agents such as pH and temperature on the activity of the amylase showed that the optimum pH and temperature for the amylase produced by the S. cerevisiae were 5.0 and 60 °C, respectively. Heavy metal resistance study on the amylolytic yeast strain indicated different levels of resistance to copper (6.0 mM), zinc (3.0 mM) and manganese (15.0 mM) ions. The results are discussed in relation to the potential use of an amylolytic yeast in the brewing industry in Nigeria.
Isozyme polymorphism of cellulases in Aspergillus terreus
Authors: Singh S. , Brar J. K. , Sandhu D. K. , Kaur A. 
Published: February 2007

AbstractMaximum cellulase production in Aspergillus terreus was obtained at a temperature of 28 °C, pH 4.0 and a substrate concentration of 1% CMC. Variability in cellulase enzyme production and isozyme polymorphism of endo‐β‐1,4‐glucanase and β‐1,4‐glucosidase was studied in 45 natural isolates of A. terreus. Different electrophoretic patterns were evident for endoglucanase. Three zones of activity viz EG 1, EG 11 and EG 111 were observed showing different electrophoretic mobilities. Some of the isolates exhibited the presence of null alleles for EG 1. During development EG 1 and EG 11 were observed throughout while EG 111 appeared on the eighth day. For β‐1,4‐glucosidase two zones of activity viz β‐glu 1 and β‐glu 11 were observed. β‐glu 1 showed variable electrophoretic mobilities. β‐glu 1 appeared throughout during development while β‐glu 11 appeared on the twelfth day.
Content of different phytohormones and indole acetic acid metabolism in root nodules of Derris scandens BENTH
Authors: De P. S. , Basu P. S. 
Published: February 2007

AbstractRoot nodules of Derris scandens BENTH., an economic leguminous climbing shrub, contain high amount of IAA, gibberellin like (GA), cytokinin like (CK) and abscisic acid like (ABA) substances. A tryptophan pool present in the nodule may serve as a source of IAA production. Metabolism of IAA in the nodules was evidenced by the presence of IAA metabolising enzymes, IAA oxidase and peroxidase. The symbiont from the nodules, a Rhizobium sp., produced high amount of IAA in culture when supplemented with tryptophan. For IAA production the bacteria preferred L‐tryptophan to DL‐ or D‐isomers of tryptophan.
Molecular analysis of the rpoD gene of Enterococcus faecalis
Authors: Frère Jacques , Gansel Xavier , Benachour Abdellah , Auffray Yanick 
Published: February 2007

AbstractThe complete nucleotide sequence of the rpoD gene of Enterococcus faecalis ATCC19433 has been determined. This gene encodes a putative 368 amino acids (aa) polypeptide of a predicted Mr of 41842 named sigma 42. Upstream of the rpoD gene and beginning from the end of the cloned chromosomal fragment is an open reading frame encoding a putative 264‐aa polypeptide. It is reminiscent of the C‐terminal domain of known DNA primase from Gram‐positive bacteria indicating that the E. faecalis rpoD gene is included in a macromolecular synthesis (MMS) operon, as it was described for Escherichia coli, Bacillus subtilis and Lactococcus lactis rpoD gene.
Induction of Rhizobium meliloti nodC gene by Alnus incana compounds
Authors: Małek Wanda 
Published: February 2007

AbstractAn expression of nodC promoter of R. meliloti 1021, cloned in front of the Escherichia coli lacZ gene, was used to study the presence of R. meliloti nodC gene‐inducing compound(s) in extracts and exudates of A. incana seeds and roots. The regulatory gene nodD was expressed at comparable level in bacterial culture of R. meliloti with and without the studied plant extracts and exudates, whereas the nodC‐lacZ fusion expression was increased 4 times by seed exudates of grey alder and 2 times by seed extracts and root ingredients in comparison to the nodC‐lacZ fusion expression in R. meliloti grown in a medium free of plant compounds. Induction of R. meliloti nodC gene expression by A. incana substances was also supported in plant test. Sterile filtrate of coculture of R. meliloti with seed exudates of A. incana induced root hair deformations and nodule‐like strutures on Medicago sativa.
Phosphorylation of ribosomal proteins by ribosome‐associated protein kinases of Trichosporon cutaneum
Authors: Wojda Iwona , Cytryńska Malgorzata , Jakubowicz Teresa 
Published: February 2007

AbstractFour ribosomal proteins of Mr 13 kDa, 15 kDa, 19 kDa and 38 kDa were identified as phosphorylation substrates for protein kinases tightly associated with Trichosporon cutaneum ribosomes. It was found that proteins of 13 kDa, 19 kDa and 38 kDa were phosphorylated by multifunctional casein kinase II while the protein of 15 kDa by casein kinase I. Proteins of 13 kDa and 38 kDa were detected in the large subunits while 15 kDa and 19 kDa in the small ribosomal subunits. By using isoelectrofocusing the protein of 13 kDa was resolved into two individual phosphorylated forms. The phosphorylation level of both forms was much higher in ribosomes from the cells collected at the exponential growth phase than in those from the stationary phase. The same phosphoprotein forms were identified in ribosomes from in vitro and in vivo [32P]‐labelling experiments.
NADP‐specific glutamate dehydrogenase of Penicillium chrysogenum has a homohexamer structure
Authors: Bogáti Magdolna Sz. , Pócsi István , Maticsek Judit , Boross Péter , Tózsér József , Szentirmai Attila 
Published: February 2007

AbstractThe NADP‐specific glutamate dehydrogenase of a high β‐lactam producing industrial strain of Penicillium chrysogenum was purified to homogeneity. The enzyme (Mr = 339000 ± 34000) was demonstrated to have a homohexamer quaternary structure with a subunit molecular mass of Mr = 56000 ± 2000. The N‐terminal sequence of the enzyme was also determined and was found to be highly homologous to other fungal NADP‐specific glutamate dehydrogenase sequences.
The variability of fungal flora in the air during morning and evening in 1994
Authors: Çolakoğlu Günay 
Published: February 2007

AbstractIn this study the variability of fungal flora in the atmosphere during morning and evening hours in different districts of Istanbul is investigated. The results are that in all districts in the evening the density is high of moulds,PenicilliumandAspergilluswhile in the morning hours,CladosporiumandAlternariadensities are high. The density ofLeptosphaeriain the atmosphere decreases at night or equalizes compared to the morning rate. The rate ofUstilagodiffers in the morning and evening hours in different districts. There is no differentiation in the build‐up rate of other fungus genera.
Effect of cassavar cultivar, age and pretreatment processes of cellulase and xylanase production from cassava waste by Trichoderma harzianum
Authors: Onilude A. A. 
Published: February 2007

AbstractCassava wastes — the peel and the root fibre were taken through various pretreatment procedures before being subjected to solid state fermentation with Trichoderma harzianum. Most of the pretreatment processes increased the cellulose and hemicellulose content of the cassava peel and fibre by as high as 155% while sulfuric acid treatment resulted in 25.3% loss in the peel hemicellulose. The best pretreatment found to be 1% NaOH at 120 °C gave the highest production of the Cx, the C1 and xylanase enzymes with the cassava root fibre. Xylanase and cellulase production with the exception of the Cx was found to be affected by age while an improved cassava variety TMS(2) 1425 peel and fibre rated highest in terms of production of the enzymes. Percentage hydrolysis within range of 56.52–67.64% were recorded for the enzymes on sorghum grains.
Cadmium‐sensitive targets in the aerobic respiratory metabolism of Staphylococcus aureus
Authors: Tynecka Zofia , Malm Anna 
Published: February 2007

AbstractStudies on the effect of various Cd2+ concentrations on substrate oxidation by whole cells of cadmium‐sensitive Staphylococcus aureus 17810S showed that oxidation of glutamate or pyruvate was highly sensitive to low Cd2+ concentrations (5 μM), whereas L‐lactate oxidation was insensitive even to high Cd2+ concentrations (100 μM). Location of the cadmium‐sensitive targets in the enzyme systems involved in oxidation of these substrates was studied in subcellular fractions prepared from cells pretreated with 5 or 100 μM Cd2+. Activities of the cytoplasmic 2‐oxoglutarate dehydrogenase complex (ODHC)1) and pyruvate dehydrogenase complex (PDHC) were strongly inhibited with 5 μM Cd2+, while with 100 μM Cd2+ the inhibition was almost complete. In contrast, activities of the cytoplasmic NAD‐dependent glutamate dehydrogenase (NAD‐GDH), the membrane‐bound NADH dehydrogenase (NDH) and HQNO‐sensitive NADH oxidase were not sensitive to 100 μM Cd2+. These data indicate that the accessible, cadmium‐sensitive targets are located only in the cytoplasmic ODHC and PDHC. It is postulated that two vicinal dithiols present in ODHC and PDHC may be regarded as the primary cadmium‐sensitive targets in the systems oxidizing glutamate or pyruvate. Since activities of the membrane‐bound NAD‐independent L‐lactate dehydrogenase (iLDH) and HQNO‐sensitive L‐lactate oxidase were not affected by 100 μM Cd2+, this indicates that the L‐lactate oxidizing system lacks the accessible, cadmium‐sensitive targets. The mechanism of Cd2+ toxicity to energy conservation with glutamate, pyruvate or L‐lactate in S. aureus is discussed.
Copurification of ribosomal protein S2 and DNA‐dependent RNA polymerase from heat‐shocked cells of Bacillus subtilis
Authors: Bütiner Knut , Pich Andreas , Neubauer Peter , Schmid Roland , Bahl Hubert , Hecker Michael 
Published: February 2007

AbstractThe DNA‐dependent RNA polymerases from heat‐shocked and vegetatively grown cells of Bacillus subtilis were isolated and compared. The RNA polymerase from non‐stressed cells had the well known a, ß, ß' and σ composition of eubacterial RNA polymerases. The RNA polymerase from heat‐shocked cells exhibited one additional band shown by SDS‐PAGE. N‐terminal sequencing of the first 16 amino acids of the associated protein demonstrated its identity with the ribosomal protein S2.
Antibacterial efficacy of new commercially manufactured disinfectant substances against Salmonella typhimurium
Authors: Majtán Viktor , Majtánová L'Ubica 
Published: February 2007

AbstractThe antibacterial effect of 19 new commercially manufactured disinfectant substances on a Salmonella typhimurium strain was studied. The substances tested represent 9 quaternary ammonium salts (QAT) and 11 combinated QAT with other ingredients. The antimicrobial efficacy was characterized by influencing the growth and reproduction of bacterial cells expressed either by MIC and ED50 values (ED50 values represent concentration of substance in μ/ml which cause inhibition of growth by 50%), as well as by the inhibition of incorporation rate of [14C] adenine and [14C] leucine. The disinfectants are divided into three groups according to their efficacy. The first group comprises substances with strong inhibitory effect (MIC 0.04–0.19 μ/ml) such as Neoquat S, Antibacteric P, Divoquat forte, Sokrena and Diesin forte (sole from the group belonging to multicomponent substances). QAT except Antibacteric P interfere with energy metabolism (R values ∼1). The second group represents substances with good antibacterial efficacy (MIC values up 1.56 μg/ml), and the third group substances with MIC values up 12.5 μg/ml. Cutasept G was found ineffective also in the concentration 100 μg/ml. The method of inhibition of [14C] precursors is suitable as one from possible criterion in evaluation of antibacterial efficacy of various synthetic substances.
Determination of the thickness of the boundary layer surrounding bacterial PHA inclusion bodies, and implications for models describing the molecular architecture of this layer
Authors: Mayer Frank , Hoppert Michael 
Published: February 2007

AbstractThe thickness of the boundary layer surrounding polyhydroxyalkanoic acid (PHA) inclusion bodies in bacteria was determined from electron micrographs of ultrathin cell sections. The obtained values were compared with the thickness of boundary layers of other kinds of prokaryotic inclusion bodies known to be monolayers (sulfur globule, hydrocarbon‐containing inclusion, carboxysome, gas vesicle, chiorobium vesicle) and the thickness of typical bilayer membranes (cytoplasmic membrane, photosynthetic vesicle). The data are discussed in view of contradicting models published recently for the molecular architecture of the boundary layer of PHA inclusion bodies.
Discoordinate gene expression of gyrA and gyrB in response to DNA gyrase inhibition in Escherichia coli
Authors: Neumann Susanne , Quiñones Ariel 
Published: February 2007

AbstractThe intracellular level of DNA supercoiling is regulated in Escherichia coli by a homeostatic control mechanism that includes DNA gyrase and topoisomerase I gene expression. Despite several biochemical and genetical evidence that supports the existence of a homeostatic regulation mechanism, there are only few studies focusing gyrA and gyrB gene expression in connection to the mechanism involved in the regulation of DNA supercoiling in vivo. To study DNA gyrase gene expression and to be able to isolate mutants with altered expression of DNA gyrase, we constructed a new chromosomal reporter system based on two translational fusions of gyrA and gyrB to lacZ. Using this stable monitor system in a robust wild type, we simultaneously studied the influence of several inhibitors of DNA gyrase (quinolones and coumarins) on gyrA and gyrB gene expression as well as on the intracellular level of DNA supercoiling. Surprisingly, we found a delayed and differential response of gyrA and gyrB gene expression following inhibition of DNA gyrase by quinolones or coumarins. Whereas both groups of drugs were able to increase the expression of gyrA, the gyrB gene expression was only induced by the coumarins. Although the action of the quinolones was able to alter DNA supercoiling, we never observed any induction of gyrB from the chromosome. These results revealed that the gene expression of gyrA appears to be more sensitive to alterations in DNA supercoiling than the gyrB gene expression and suggest that probably additional regulatory mechanisms on the post‐translational level might be involved in the regulation of DNA supercoiling and DNA gyrase gene expression.
Three Bacillus thuringiensis flagellar serovars widely occurring in natural environments of Japan
Authors: Ohba Michio 
Published: February 2007

AbstractThree Bacillus thuringiensis flagellar (H) serogroups were newly detected in the populations associated with sericultural and natural environments of Japan. A total of 44 B. thuringiensis strains, derived from seven prefectures in Honshu, Shikoku, and Kyushu, were assigned to the H serotypes 34 (serovar konkukian), 35 (serovar seoulensis), and 43 (serovar guiyangiensis). Of the 44 strains, three of the serovar konkukian and one strain of the serovar guiyangiensis exhibited moderate larvicidal activity specific for the mosquito, Aedes aegypti. None of the strains showed toxicity against larvae of the silkworm, Bombyx mori.
Optimization of catalase biosynthesis in submerged cultures of Aspergillus niger mutant
Authors: Gromada A. , Fiedurek J. 
Published: February 2007

AbstractThe effect of some medium components, viscous substances and metabolic inhibitors, on catalase production by mutant Aspergillus niger has been studied in shake culture. Altering the composition of the basal medium, particularly substituting NaNO3 for KNO3, and peptone for yeast extract brought an increase in extra‐ and intracellular catalase activity by 1.5‐ and 3‐fold, respectively. The addition of 2.0–6.0 mg sodium alginate or pectin/ml as viscous additive to the medium, containing glucose as carbon source, increased the medium viscosity and catalase production in shake culture by about 2.8‐ to 3.0‐fold. The highest yield of extracellular catalase activity of A. niger was obtained in the presence of sodium orthovanadate and Triton X‐100, which improved the activity of this enzyme by about 1.5‐2.2‐fold. A significant increase in intracellular catalase activity was observed in the presence of hematin, Tween 80 and sodium orthovanadate (1.7‐, 1.6‐ and 1.4‐fold respectively). The time course of growth and enzyme production by A. niger in the optimized medium is also reported.
Diversity within bacterial isolates hybridizing with Comamonas probe ppT
Authors: Koivula Teija T. , Hantula Jarkko 
Published: February 2007

AbstractDiversity within bacteria isolated from activated sludge and the Baltic sea and recognized by the rRNA targeted oligonucleotide probe ppT (designed by BRAUN‐HOWLAND et al., 1993 to recognize C. testosteroni) was studied. The partial nucleotide sequences of 16S genes of the isolates revealed that the activated sludge and Baltic sea isolates each formed a separate group distinct from C. testosteroni. The analysis of phage and bacteriocin sensitivity as well as whole cell protein patterns revealed the same grouping, but in these characters also intragroup variation was observed. As a conclusion, neither of the studied groups were C. testosteroni, but they probably belong to two previously unknown species common in activated sludge or the Baltic sea.