bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of the bacterial degradation of phenoxyalkanoate herbicides by the use of modified polyurethane foam as a support
Authors: Hinteregger Christel , Loidl Michael , Stockinger Johannes , Streichsbier Franz
Published: February 2007

The enhancement of the degradative behaviour of Flavobacterium sp. MH concerning the phenoxyalkanoate herbicides 2,4‐D, 2,4‐DP, 2,4‐DB, MCPA, MCPP, and MCPB, respectively, was achieved by the use of an inert polyurethane (PU)‐foam. In comparative batch‐degradation experiments with and without the addition of the PU‐carrier (1.25 % w/v), respectively, the advantages of the PU‐supply were demonstrated. When 2,4‐D, 2,4‐DP, and MCPP, respectively, was used as a growth substrate by strain MH the PU‐supply led to a reduced lag‐phase. In the case of the stronger toxic phenoxyalkanoates 2,4‐DB and MCPB, respectively, the inital substrate concentration (0.1 g/1) was significantly reduced to a minor toxic concentration due to a distinct adsorption to the PU‐carrier, thus enabling the biodegradation. Finally, the total initially supplied amount of the phenoxyalkanoates was detoxified as verified by thechloride balance. After several steps of subcultivation, even a five‐fold increased MCPB concentration (0.5 g/1) could be detoxified by strain MH in a PU‐supplied bubble reactor within several days.
Characteristics of NaCl stress associated proteins of Rhizobium under varying cultural conditions
Authors: Natarajan K. , Kishore L. , Babu C. R.
Published: February 2007

Sodium chloride stress results in the possible induction of high molecular weight proteins and elevated levels of already existing proteins. These proteins are cytosolic and acidic in nature and are not induced by heat stress. It appears that the cell envelope in DDSS 69 may play a limited role in osmotolerance. Osmoprotectants betaine and glutamate have differential effects on the stress proteins at elevated osmolarities.
Host‐phage interactions under osmotic stress in Nostoc muscorum
Authors: Pandey U. , Singh S. P.
Published: February 2007

Cyanophage N‐1 multiplication in Nostoc muscorum exposed to osmotic stress was studied. Osmotic stress (0.1 M NaCl, 2–8 h), reduced the host photosynthesis and nitrogenase activity. Latent period of the virus was extended followed by a significant reduction in burst size. The deployment of osmo‐tolerant host and a osmoprotective agent, glycine betaine (1 mM), improved cyanophage yield. The observations form the first report of cyanophage multiplication in a cyanobacterium exposed to osmotic stress and modifications by a osmoprotective agent or by a osmotolerant host.
Fast dissociation of phe‐tRNA synthetase from Aspergillus nidulans immobilized on sepharose‐6B column by NaCl
Authors: Singh Nalin Kumar , Tiwary Bhupendra N.
Published: February 2007

Phenylalanyl‐tRNA2) synthetase from Aspergillus nidulans was efficiently immobilised to sepharose 6B column containing phenylalanine as the ligand. NaCl was found to be a potent dissociating agent for the immobilised enzyme. While 0.5 M NaCl in discontinuous elution showed a slow impetus on dissociation giving a plateaux profile, a solution of 0.8 M NaCl made the eiution rapid giving a sharp peak. On the other hand, in a gradient (continuous) elution the rapidity of dissociation was found to be enhanced with the increase in the difference of the two concentrations. The result suggests that Na+ ions interact with the protein binding site of the ligand eventually dissociating the enzyme molecule by disrupting the covalent bond without affecting its normal catalytic activity.
Synthesis and secretion of recombinant penicillin G acylase in bacterial L‐forms
Authors: Gumpert Johannes , Cron Heinrich , Plapp Roland , Niersbach Helmut , Hoischen Christian
Published: February 2007

L‐form strains of Proteus mirabilis and Escherichia coli lacking the cell wall represent an alternative prokaryotic cell system for the production of recombinant proteins (KLESSEN et al. 1988, LAPLACE et al. 1988 a, 1989b). We could demonstrate that they are also able to synthesize the enzyme penicillin G acylase (PAC)1). PAC was processed and secreted into the medium by recombinant L‐form strains. The synthesis of PAC was growth‐associated and stably regulated. Expression, secretion, and processing were not temperature‐dependent and occurred at 26 °C, 32 °C and even 37 °C. The expression vector pHC1 carried the pac gene under the control of the lac UV promoter and a kanamycin resistance gene. It could be maintained in L‐form cells, showing low structural as well as segregational instability. The secretion of the biologically active enzyme into the medium indicated that the postranslational processing of the PAC molecule, including the excision of a 54 amino acid spacer peptide between the α and β subunit, is not carried out in the periplasmic space, but occurs at the cytoplasmic membrane or autocatalytically.
Low energy gain from formate oxidation during bacterial growth on 2,4‐dichlorophenoxyacetic acid
Authors: Müller Roland H. , Babel Wolfgang
Published: February 2007

Alcaligenes eutrophus JMP 134 was chemostatically grown on 2,4‐dichlorophenoxyacetic acid (2,4‐D) at a dilution rate of 0.06 h−1; formate was fed as an auxiliary energy source. The simultaneous utilization of both components resulted in an increase in growth yield. As an example, this figure increased from 0.18 g dry mass/g 2,4‐D to 0.25 g dry mass/g 2,4‐D during growth on 1 g/l 2,4‐D plus 3 g/l sodium formate. The increase was correlated to energy generated from formate oxidation. Accordingly, a P/O‐quotient of 1 was derived for the energy transduction of NADH obtained from formate oxidation as it was for the overall efficiency during growth on 2,4‐D itself. This low energy yield was attributed to uncoupling exerted by 2,4‐D. The theoretical maximum yield coefficient of 0.69 g/g could not be reached due to the limiting activity of formate dehydrogenase in the conversion of the required quantities of formate.
Bacterial diversity at surface water in three locations within the Baltic sea as revealed by culture‐dependent molecular techniques
Authors: Hantula Jarkko , Koivula Teija T. , Luo Cheng , Bamford Dennis H.
Published: February 2007

Diversity of culturable bacteria inhabiting the Baltic sea surface waters was studied in three separate locations. Based on electrophoretically separated whole cell proteins the number of operational taxonomic units (OTU) within each sampling location was high. Most of the OTUs were unique to single locations. Within each sampling location 8–22% of isolates belonged to a single OTU. Rarefaction analysis revealed that the bacterial community was more divergent at a polluted location than at clean areas. Also the most common OTUs were different in clean locations compared to the polluted site suggesting that both diversity and species composition of the bacterial community is greatly affected by pollution. The partial 16S rRNA gene sequences of the isolates of the most common OTUs are unique. Intragroup variation and an OTU‐specific bacteriocin system was observed among the isolates of the second common OTU. The bacteriocin activity was linked to restriction fragment length polymorphism grouping, although additional variation correlating to geographic origin of isolates was observed.
Xylose reductase and xylitol dehydrogenase activities of D‐xylose‐xylitol‐fermenting Candida guilliermondii
Authors: Silva S. S. , Vitolo M. , Pessoa A. , Felipe M. G. A.
Published: February 2007

The effect of the inoculum age and initial xylose concentration on the activities of xylose reductase (XR) and xylitol dehydrogenase (XD) of Candida guilliermondii FTI 20037 were investigated. Under the experimental conditions used, the XR and XD activities were, respectively. NADPH and NAD or NADP dependent. The NADP/NADPH ratio for XR was not substantially influenced by the age of inoculum or the initial xylose concentration. The Km of XR (0.18 M) was about 4‐folds smaller than the Km of XD NAD‐dependent. A renewable xylose‐xylitol conversion was obtained with 40 h aged inoculum of Candida guilliermondii FTI 20037 grown in a medium containing an initial xylose concentration of 120g/l.
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

Continuous 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

The 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

In 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

Twelve 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

The 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

The 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

An 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

Maximum 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

Root 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

The 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

An 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

Four 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

The 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

In 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

Cassava 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

Studies 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

The 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

The 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

The 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

The 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

Three 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

The 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

Diversity 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.
Evidence for and characterization of cytochrome P‐450 in Neurospora crassa
Authors: Nega Eva , Grunwaldt Gisela
Published: February 2007

Cytochrome P‐450 was detected in microsomes and presumably in cytosol of Neurospora crassa, and was found to be inducible by progesterone. In the microsomal fraction cytochrome b5 and NADPH‐cytochrome c reductase activities were measurable, too. Cytochrome P‐450 of Neurospora crassa is inhibited by SKF‐525 A and by inhibitors of ergosterol biosynthesis. After induction of cytochrome P‐450 with progesterone 11α‐hydroxyprogesterone as one metabolite of progesterone was detected in the culture media as well as in the mycelia. After 42 hours about 70% of progesterone were metabolized.
In vitro studies on antifungal activity of tea (Camellia sinensis) and coffee (Coffea arabica) against wood‐rotting fungi
Authors: Arora D. S. , Ohlan D.
Published: February 2007

The present study reports the sensitivity of ten different wood‐rotting fungi towards eight samples of tea and two samples of coffee. The tea samples included five CTC black teas, one orthodox black tea and two green teas. The different fungi tested were sensitive to different tea and coffee samples to variable levels. Green tea caused the maximum growth inhibition and it was 100% in case of Phanerochaete chrysosporium and Sporotrichum pulverulentum. Of the black tea samples, orthodox black tea was more effective inhibitor for all the fungi tested. Phlebia radiata was the most sensitive fungus to all the black tea samples except Lipton Cheers. The growth of Daldinia concentrica was least affected by all the black tea samples. The two coffee samples showed better inhibition than CTC black tea samples. The inhibitory effect of tea and coffee extracts was greatly reduced on their filtration. All the tea and coffee samples tested showed more than 50% reduction in their inhibitory activity. The inhibitory effect was completely lost in spent black tea leaves. The antifungal effect of pure caffeine was tested at different concentrations. Majority of the fungi were totally inhibited at a concentration of 0.3% whereas, D. concentrica, P. radiata and P. palustris showed complete inhibition at a concentration of 0.5 percent.
Characterization of a bacterial consortium degrading the lignin model compound vanillyl‐β‐D‐glucopyranoside
Authors: Céspedes Ricardo , González Bernardo , Vicuña Rafael
Published: February 2007

Aryl‐β‐D‐glycosides have been described as intermediates in lignin biodegradation. The catabolism of this kind of compounds has been poorly studied. In this work, the isolation and initial characterization of a bacterial consortium degrading vanillyl‐β‐D‐glucopyranoside is reported. The consortium is able to grow on and completely degrade the dimer vanillyl‐β‐D‐glucopyranoside. The consortium is composed of three microorganisms: strain 2.1 is closely related to Chryseomonas luteola; strain 2.2, identified as Moraxella phenylpyruvica and strain 2.3, preliminary identified as Pseudomonas spp. Complete degradation of the glycoside required strains 2.1 and 2.2, although only strain 2.1 was able to cleave the aryl‐glycoside linkage. Oxidation of vanillyl alcohol, one product of the aryl‐glycoside cleaving reaction, to the respective acid was carried out by strain 2.2. Vanillic acid was used as growth substrate by strains 2.2 and 2.3. Strain 2.1 can grow on other aryl‐β‐glycosides, accumulating the aryl moiety in the culture. β‐Glucosidase present in strain 2.1 is probably the key enzyme in the catabolism of aryl‐glycosides by this consortium.
Phenoxyacetic acid induces glutathione‐dependent detoxification and depletes the glutathione pool in Penicillium chrysogenum
Authors: Emri Tamás , Pócsi István , Szentirmai Attila
Published: February 2007

Enzymes of the glutathione‐dependent detoxification pathway (glutathione S‐transferase and γ‐glutamyl‐transpeptidase)1) were induced, and the glutathione pool was completely depleted by phenoxyacetic acid in Penicillium chrysogenum mycelia incubated for 15 h in a culture medium containing lactose as a carbon source and sodium glutamate as a nitrogen source. A significant increase in both the oxidised glutathione concentrations and the glutathione reductase activities were also observed. 1‐Chloro‐2,4‐dinitrobenzene ‐ a potent substrate and inducer of glutathione S‐transferase ‐ initiated very similar physiological changes but no β‐lactam production could be detected in this case. When (NH4)2HPO4 was used as a nitrogen source the penicillin biosynthesis was repressed and the induction of γ‐glutamyltranspeptidase by phenoxyacetic acid was hindered considerably.
Effect of the carbon source succinate on pyrimidine synthesis in Burkholderia cepacia
Authors: Li Ke , West Thomas P.
Published: February 2007

The effect of the carbon source succinate on pyrimidine synthesis in the pathogen Burkholderia cepacia ATCC 25416 was investigated. The five de novo pathway enzyme activities of pyrimidine biosynthesis in B. cepacia were shown to be affected when ATCC 25416 cells were grown in the presence of uracil. Pyrimidine limitation of a uracil auxotrophic B. cepacia strain lacking orotidine 5′‐monophosphate decarboxylase activity increased aspartate transcarbamoylase, dihydroorotase, dihydroorotate dehydrogenase and orotate phosphoribosyltransferase activities by at least 1.5‐fold which indicated that these pathway enzymes may be regulated by a uracil‐related compound. The levels of the de novo pyrimidine biosynthetic enzyme activities in B. cepacia ATCC 25416 cells appeared to be influenced to a greater degree in cells grown on succinate than on glucose as a carbon source.
Heavy metal resistant Arthrobacter sp. — A tool for studying conjugational plasmid transfer between Gram‐negative and Gram‐positive bacteria
Authors: Margesin R. , Schinner F.
Published: February 2007

The role of two heavy metal‐resistant strains of the Gram‐positive genus Arthrobacter sp. as a tool in studying conjugational plasmid transfer between Gram‐positive and Gram‐negative bacteria is described. The high nickel resistance and the cobalt resistance of Arthrobacter sp. strain RM1/6 could be transferred to Arthrobacter sp. strain WS14. IncQ plasmids (pKT240, pKT240::czc, pML10) could be mobilized from E. coli into Arthrobacter spp. strains; antibiotic (Km, Ap, Tc)1) and heavy metal (Co) resistance genes were expressed in the recipient strains. IncQ plasmid pKT240 could be mobilized between Arthrobacter spp. strains. IncP plasmid RP4::Tn4371 was transferred from A. eutrophus to Arthrobacter sp., RP4‐mediated antibiotic resistance to Km was expressed in the recipient strain.
Evaluation of the Staph‐Zym system in the identification of staphylococci isolated from ovine milk and the ewe environment
Authors: Burriel Angeliki Rothi , Scott Maggie
Published: February 2007

The Staph‐Zym and the Rosco Set methods were used to assign species to 142 strains of staphylococci isolated from the milk of sheep with subclinical intramammary infection or teat skin, mouth of lambs or milking machine teat cups. One hundred eleven of the same strains were also tested by Standard Laboratory Culture Media. The Rosco Set assigned species to all strains tested, but the other two methods were unable to assign species to a similar proportion of isolates. Seventy six (68.5%) of the strains tested with all three methods were not assigned the same species, each method shown a preference for particular species. The Staph‐Zym and the Rosco Set identified most of the strains as members of the ‘epidermidis’ group with the ‘aureus’ second, while the reverse was observed with the Standard Laboratory Culture Media. Only in the case of Staphylococcus epidermidis all methods were in close agreement. When the results of the Staph‐Zym and the Rosco Set are compared, although they agree on the predominant group, they disagree on the predominant species within the same group.
Relationship between the thermotolerance and the increase of DnaK and GroEL synthesis in Enterococcus faecalis ATCC19433
Authors: Flahaut Sigrid , Frere Jacques , Boutibonnes Philippe , Auffray Yanick
Published: February 2007

Relationship between intrinsic thermal resistance, thermotolerance and heat shock proteins (hsp) synthesis is studied in Enterococcus faecalis. We showed that an impressive phenotypic heat resistance was induced by mild heat and a slight thermotolerance was developed by various sublethal pretreatments such as NaCl, SDS and bile salts. Hydrogen peroxide, acid and alkalin shifts or ‘thermomimetic’ agent such as ethanol, did not enhance the survival of adapted cells against the lethal thermal shock (62 °C). The inhibition of protein synthesis by chloramphenicol or rifampin abolished thermotolerance. The immunological identification of the DnaK and GroEL proteins in E. faecalis allowed to study induction of these molecular chaperones under various conditions. Heat was the most efficient inductor of DnaK and GroEL synthesis. However, it was surprising that ethanol did not strongly induce these proteins. We also show that amplification of these hsp is not correlated to acquired thermotolerance with a linear relationship. A weak thermotolerance is not coupled from increased synthesis of DnaK and GroEL. So, we postulate that the high synthesis of the major hsp is not obligatory in the thermal cross‐protection but that de novo protein synthesis is an absolute necessity in E. faecalis. Activation of preformed hsp or other factors depending or not on protein synthesis may be also necessary to enhance thermal resistance.
UV‐B and heat shock‐induced changes in the wild type and UV‐B heat shock‐tolerant (UV‐HSt) strain of the unicellular cyanobacterium Anacystis nidulans
Authors: Gour R. K. , Singh S. , Pandey P. K. , Bisen P. S.
Published: February 2007

Ultraviolet‐B and heat shock (HS)1) induced changes in growth kinetics, NO−3 reductase (NR), glutamine synthetase (GS), NO−3 uptake and NO−2 efflux activities, have been studied in the wild type Anacystis nidulans and its UV‐HS1 strain. The application of UV‐B and HS stresses either used separately or in combination shows a drastic changes in growth rates of wild type, and insignificant effect on the growth of the UV‐HSt strain. The wild type cells, in contrast to its UV‐HSt strain exhibits insignificant effect on NR and GS activities upon UV‐B radiation followed by heat shock treatment. Similar treatments to the wild type cells resulted in maximum reduction of NR and GS activities. The NO−3 uptake and NO−2 efflux activities are found to be lower in the UV‐HSt strain than in the wild type counterpart and both the systems consisted of an initial rapid phase followed by a slower one. NH+4 grown cells when transferred to NO−3 medium in presence of streptomycin showed significant inhibition in the development of both the NO−3 uptake and NO−2 efflux systems indicating that de novo protein synthesis is required for the development of NO−3 uptake and NO−2 efflux systems. Whereas the same cells in the presence of L‐methionine‐DL‐sulfoximine (MSX) showed marginally higher NO−3 uptake but, exhibits only 42% NO−2 efflux to that of MSX‐devoid both the cells. It is suggested that NH+4 assimilation via GS is necessarily required for NO−2 efflux system to be functional.
Purification and properties of methanol dehydrogenase from Methylocystis sp. GB 25
Authors: Grosse Stephan , Wendlandt Karin‐Dagmar , Kleber Hans‐Peter
Published: February 2007

Methanol dehydrogenase (MDH) from Methylocystis sp. GB 25, which belongs to the group II of methanotrophic bacteria, is able to catalyse the oxidation of methanol to formate directly. The enzyme was purified 20‐fold by a 5 step procedure to electrophoretic homogeneity. After cell disruption by French press, about 95% of MDH‐activity was found in the soluble fraction. The relative molecular mass of the native enzyme has been estimated to be 122 kDa by gel filtration and 115 kDa by the method of HEDRICK and SMITH (1968). It seems to be composed of two identical subunits with a relative molecular mass of 62 kDa (estimated by SDS gel electrophoresis). The isoelectric point was found to be about 8.3. The amino terminal sequence shows a strong similarity to the α‐chain of MDH from the facultative methylotrophic bacterium Methylobacterium extorquens AM1. PQQ, the probable prosthetic group of MDH, could be detected in the supernatant of the culture by using the apoenzyme of a membrane‐bound glucose dehydrogenase from Pseudomonas aeruginosa but not absolutely in the absorption spectra of the enzyme after DEAE‐chromatography. The purified MDH has an optimum activity at pH 9.0 and at 45 °C. MDH of Methylocystis sp. GB 25 oxidises only primary alcohols from methanol to heptanol and aldehydes from formaldehyde to propionaldehyde and the glutaraldehyde, respectively. The estimated Km‐values show no dependence upon the chain length of substrates.
Physiological and biochemical characterization of intergeneric hybrids of thermotolerant and non‐thermotolerant yeasts
Authors: Dhamija S. S. , Gera R. , Singh D. K. , Singh D. , Marchant R.
Published: February 2007

Kluyveromyces‐like intergeneric hybrids of thermotolerant Kluyveromyces marxianus and non‐thermotolerant Saccharomyces cerevisiae, produced in a previous study by protoplasmic fusion, have been characterized. On molasses, these strains produced ethanol in excess of 6% (v/v) both at 30 and 45 °C as against 3% and 4.2% (v/v) by the former parent at 30 and 45 °C, respectively. In hybrids, the increase in ethanol production appeared to be a sequel to increased activities of alcohol dehydrogenase and pyruvate kinase, derived probably from S. cerevisiae parent. Hybrid ADH‐isozyme pattern on polyacrylamide gel corroborated the presence of S. cerevisiae ADH in the tested hybrids. Regression analyses indicated a positive correlation between ethanol production and ADH or PK or both (r ∼ 0.76–0.84).
Epizootic of Chlamydia psittaci infection in goats in Taiwan
Authors: Liao Y. K. , Chain C. Y. , Lu Y. S. , Li N. J. , Tsai H. J. , Liou P. P.
Published: February 2007

Epizootic abortion in goats has been frequently reported in Taiwan since 1993. The outbroken flocks were found in most of districts in Taiwan. No apparent clinical signs were found in aborted doe. The typical abortion occurred in the last two months of pregnancy. The incidence of abortion was from 10% to 87% in outbroken farms in 1993, and a total of 976 out of 2130 pregnancies (46%) were found abortion in our investigation. Gross lesions in aborted fetuses included generalized haemorrhage and swollen liver. Chlamydia psittaci was isolated from tissues of aborted fetuses and from vaginal swabs of aborted does. Chlamydial antibodies were detected among 67% to 100% of aborted does from epizootic flocks. The C. psittaci was diagnosed as the causal agent in enzootic abortion. This is the first report on chlamydial isolation and antibody surveys in epizootic abortion in goats in Taiwan.
Effects of pH on the comparative culturability of fungi and bacteria from acidic and less acidic forest soils
Authors: Matthies Carola , Erhard Hans‐Peter , Drake Harold L.
Published: February 2007

Under aerobic conditions, the culturable microbial population of acidic forest soils was more tolerant to acidic cultivation conditions than was the culturable microbial population of less acidic soils. The number of culturable bacteria decreased sharply under acidic cultivation conditions, while the number of culturable fungi remained relatively constant over the pH range 2.2–6.5. The ratios of culturable bacteria to culturable fungi were greater than one at pH 6.5; in contrast, the bacteria‐to‐fungi ratios were less than one at pH 2.2–4. At pH's approximating those of the soils examined, culturable fungi predominated the culturable microbial community in acidic soils. However, relative to the populations resolved, acidic forest soils displayed a more acid tolerant bacterial population than did less acidic forest soils. The culturable fungal population contained both filamentous and yeast morphologies. An acid‐tolerant fungal isolate that grew at pH 1 was identified as a subspecies of Penicillium frequentans, and an acid‐tolerant yeast that grew at pH 2 was identified as the yeast stage of the basidiomycetes Ustilago maydis.