bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrically induced protoplast fusion for ergosterol‐producing yeast strain improvement
Authors: Avram Dorina , Petcu Ileana , Radu Mihai , Dan Florica , Stan Rodica 
Published: February 2007

AbstractElectrofusion was employed for hybrid construction in ergosterol‐producing yeast strains. Some fusion products proved to be hybrid with respect to ergosterol content and to remain stable over several generations.
pH‐Abhängigkeit der Cytochromc2(c)‐Reduktion und des Membranpotentials (Δ Ψ) in Modellsystemen und Chromatophoren von Purpurbakterien
Authors: Oleskin Alexander V. , Samullov Vitaly D. 
Published: February 2007

AbstractUbiquinol‐1 reduces cytochromecin solution at a rate which increases 10‐fold with an increase in pH by one unit within the range of 6.5 – 8.5. Light‐dependent generation of ΔΦ in proteoliposomes containingRhodospirillum rubrumreaction centers in the presence of ubiquinone‐1 and cytochromecis also stimulated with an increase in pH from 6.5 to 8.5. The ΔΦ generation inR. rubrumandRhodobacter sphaeroidesis described by a bell‐shaped pH‐dependence curve, the maximum responses being observed at pH 7.5–8.0. The dependence is retained with antimycin A (but not myxothiazol). The magnitude of the residual ΔΦ generation in the presence of myxothiazol or its combination with antimycin remains relatively constant in the pH range 6.5 to 9.5. Switching off the light, cytochromec2is reduced inRb. sphaeroideschromatophores, with the maximum rate at pH 7.3 – 7.6. The data obtained suggest that cytochromec2reduction by ubiquinol in purple bacteria is accomplished by cytochromebc1complex. In proteoliposomes and soluble systems, this process depends on a direct nonenzymatic reaction.
Metabolism of PAH by fungi and correlation with extracellular enzymatic activities
Authors: Sack Ute , Günther Thomas 
Published: February 2007

AbstractThe activity to metabolize the polycyclic aromatic hydrocarbons (PAH) phenanthrene, anthracene, pyrene, fluorene and fluoranthene by Trametes versicolor, Pleurotus ostreatus (white rot fungi), Laetiporus sulphureus, Daedaela quercina, Flamulina velutipes (brown rot fungi), Marasmiellus sp. (litter decaying fungus) and Penicillium sp. M 1 (isolated from a PAH contaminated soil sample) were compared. Screening methods for the presence of exoenzymes (peroxidases, polyphenoloxidases, “radical generating” enzymes) were evaluated for their use in screenings for fungi degrading PAH. Laetiporus sulphureus and Penicillium sp. M 1 cometabolize several PAH with rates comparable to white rot fungi. In most of the cases the patterns of extracellular peroxidases indicate the potential of fungi to degrade PAH.
Survey of mycoflora and mycotoxins of some dried fruits in Egypt
Authors: Zohri A. A. , Abdel‐Gawad Khayria M. 
Published: February 2007

AbstractFifty‐five species and two varieties appertaing to 23 genera were collected and identified from 4 samples of dried fig and 3 dried samples of each of apricot, plum and raisin. Forty‐nine species and two varieties belonging to 20 genera were isolated on 1% glucose‐CZAPEK's while 31 species and one variety belonging to 16 genera were isolated on 40% sucrose‐CZAPEK's agar medium at 28 ± 2 °C.Penicillium, Aspergillusandcladosporiumwere the common genera on the two types of media used.AlternariaandPleosporawere common on 1% glucose‐CZAPEK's agar only while the genus ofEurotiumwas isolated with high occurrence on 40% sucrose‐CZAPEK's agar. The common species on the two types of media used werePenicillium chrysogenum, Aspergillus nigerandcladosporium cladosporioides. On 1% glucose‐CZAPEK's agar.P. aurantiogriseum, A. fumigatus, A. flavus, Alternaria tenuissimaandPleospora herbarumwere isolated with high occurrence whileA. versicolor, A. wentii, Eurotium amstelodamiandE. chevalieriwere common on 40% sucrose‐CZAPEK's agar.The different dried fruit samples were assayed for the natural occurrence of aflatoxins B1, B2, G1& G2, citrinin, ochratoxins, patulin, sterigmatocystin, diacetoxyscirpenol. T‐2 toxin and zearalenone by thin layer chromatographic analysis. Ochratoxin A was detected in all samples tested of apricot (50–110 μg/kg), fig (60–120 μg/kg) and plum (210–280μg/kg). The other mycotoxins under investigation were not detected. All samples examined of raisin proved to be mycotoxin free.
Temperature‐dependent expression of conjugation pili by IncM plasmid‐harbouring bacteria: Identification of plasmid‐encoded regulatory functions
Authors: Tietze Erhard , Tschäpe Helmut 
Published: February 2007

AbstractA 1,3 kb DNA fragment of the IncM plasmid R446, if cloned in a multicopy plasmid, inhibits in trans the expression of conjugation pili by IncM plasmid‐harbouring host bacteria as indicated by their insensitivity to the IncM pilus‐dependent bacteriophage ϕM (Iml, insensitivity to ϕM‐mediated lysis). Determination of the nucleotide sequence of this DNA fragment, the introduction of deletions and the analysis of transposon insertions reveal two determinants, imlA and imlB, responsible for the Iml phenotype. A stretch of 80 bp of DNA containing imlA and about 450 bp of adjacent DNA comprising imlB, together, bring about inhibition of the typical expression of conjugation pili at 30 °C. The introduction of a transposable promoter probe and the construction of respective lacZ fusions indicate transcription of complementary strands in vivo overlapping in the region comprising imlA and imlB. Moreover, the expression of reporter genes discloses temperature‐dependent transcription of the imlA‐imlB‐region in one direction.A particular subfragment of the 1.3 kb IncM plasmid‐derived DNA does not inhibit conjugation pilus expression at 30 °C but stimulates in trans the formation of pili at 42 °C to give rise to untypical sensitivity to ϕM at 42 °C in addition to 30 °C. Other subfragments reveal vital interferences with IncM plasmid‐harbouring host cells.The putative nature of the cloned determinants interfering with the normal expression of IncM plasmid DNA is discussed.
Unspecific degradation of halogenated phenols by the soil fungus Penicillium frequentans Bi 7/2
Authors: Hofrichter Martin , Bublitz Friedemann , Fritsche Wolfgang 
Published: February 2007

AbstractResting phenol‐grown mycelia of the fungus Penicillium frequentans strain Bi 7/2 were shown to be capable of metabolizing various monohalogenated phenols as well as 3,4‐dichlorophenol. 2,4.dichlorophenol could be metabolized in the presence of phenol as cosubstrate. In the first degradation step the halogenated phenols were oxidized to the corresponding halocatechols. Halocatechols substituted in para‐position (4‐halocatechols) were further degraded under formation of 4‐carboxymethylenbut‐2‐en‐4‐olide. A partial dehalogenation took place splitting the ring system. 3‐Halocatechols were cleaved to 2‐halomuconic acids as dead end metabolites without a dehalogenation step. Dichlorophenols were only transformed to the corresponding catechols. In addition 3,5‐dichlorocatechol was O‐methylated to give two isomers of dichloroguaiacol. The halogenated catechols with the exception of 4‐fluorocatechol partly polymerized oxidatively in the culture fluid to form insoluble dark‐brown products. The degradation of halophenols are due to the action of unspecific intracellular enzymes responsible for phenol catabolism (phenol hydroxylase. catechol‐1,2‐dioxygenase, muconate cycloisomerase I).
Factors influencing β‐galactosidase activity ofAeromonas caviae
Authors: Karunakaran T. , Devi B. G. 
Published: February 2007

AbstractAeromonas caviae, often reported to be associated with diarrhoeal patients, elaborates several virulence factors as well as catabolic enzymes such as xylanase and β‐galactosidase. Studies on the kinetics of growth ofA. caviaeand synthesis of β‐galactosidase suggested that the activity was cell associated and reached a peak during the late logarithmic phase of growth. The optimum pH for β‐galactosidase activity was 7.0 and required Ca2+and glutathione for enhancement of its activity; IPTG also slightly improved the activity. Aerobic cultivation ofA. caviaein LB containing glucose, fructose, maltose and sucrose completely inhibited the activity possibly due to acetic acid production. Addition of 100 mM cAMP to the media containing glucose (0.25%, w/v) restored the relative activity by 8.8%; however, the final pH of the media remained acidic. Aerobic growth ofA. caviaewith other carbon sources did not affect β‐galactosidase activity, probably as there was no acid production and thereby the final pH of the media unaltered. Arabinose, xylose and galactose induced theA. caviaeβ‐galactosidase activity by several folds and lactose moderately enhanced its activity.
Cellulase activity and succession of fungi in soil amended with sodium chloride, organic matter and Ca‐superphosphate
Authors: Abdel‐Sater M. A. 
Published: February 2007

AbstractThe fungal population in soil amended with 2.5, 5 and 10% sodium chloride, sodium chloride with either 5% organic matter or 1% Ca‐superphosphate and incubated at 25 °C was studied after 2, 4 and 8 weeks. Sixty‐six species and 5 varieties belonging to 35 genera were isolated from the treated and untreated soils on glucose‐, cellulose‐ and 10% NaCl‐Czapek's agar at 25° or 45 °C. The total propagules, total counts ofAspergillusand counts 6f several species were significantly promoted with the low concentration of NaCl (2.5%) and decreased with the rise of NaCl levels. Also, the total counts of fungi were significantly flourished in soil amendment with sodium chloride when combined with organic matter or fertilizer after some storage periods. Several glucophilic, cellulose‐decomposing, xerophilic and thermophilic fungi were found to tolerate the previous conditions. The cellulolytic activities of most isolates tested were inhibited either by sodium chloride or combined with superphosphate and organic matter.
Ecological and physiological studies on thermophilic bacilli from sulfataric hot springs of central Italy
Authors: Canganella Francesco , Trovatelli Luigi Daniele 
Published: February 2007

AbstractHot springs located in a geothermal area of central Italy were investigated with respect to the total number of thermophilic microorganisms as well as to the presence of amylolytic and pullulolytic bacteria. A number of motile thermophilic spore‐forming bacteria were isolated from different sites. The aerobic organisms grew optimally at 60 −65°C on yeast extract‐trypticase and/or xylose‐starch supplemented mineral medium and spores were mostly observed on agar plates after prolonged incubation. According to the results based on phenotypic characterization, G + C% and lipid analyses all the aerobic isolates belong to the genus Bacillus and are characterized by an unusual G + C content ranging between 33.4 ‐ 38.8. A limited number of anaerobic organisms were also isolated and investigated for the presence of amylolytic and pullulolytic activity. According to physiological tests these isolates were identified as Clostridium thermohydrosulfuricum; when grown on starch, they produced thermostable α‐amylases, pullulanases and α‐glucosidases.
Thermally‐induced cell lysis in Escherichia coli K12
Authors: Membrillo‐Hernández Jorge , La Mora Alejandra Núñez‐De , Del Rio‐Albrechtsen Tania , Camacho‐Carranza Rafael , Gomez‐Eichelmann M. Carmen 
Published: February 2007

AbstractEscherichia coli cells exposed to high temperatures exhibit a progressive loss of viability. We observed two mechanisms of cell death induced by lethal temperatures: with and without lysis. The number of cells lysed by heat decreased at later stages of the growth curve, when cells were pre‐treated at lower temperatures for 10 minutes and when cells were pre‐treated with novobiocin, nalidixic acid and cadmium chloride. Cell lysis was similar in wild type, rpoH, groE and dnaK mutant cells as well as in cells which overproduce heat shock proteins GroE or DnaK. Results using cells aligned for cell division and cells growing at 42°C, 45°C and 47°C suggest that cells near division are more sensitive to lysis and that a high concentration of heat‐shock proteins increases their resistance to lysis.
Simultaneous raw starch hydrolysis and ethanol fermentation by glucoamylase from Rhizoctonia solani and Saccharomyces cerevisiae
Authors: Singh Dalel , Dahiya Jagroop S. , Nigam Poonam 
Published: February 2007

AbstractCrude glucoamylase preparation from Rhizoctonia solani was used to saccharify raw and cooked starch. Various concentrations of potato starch and wheat flour from 10–40%, w/v were used for mashing but 30% was found to be the optimal and economical. The saccharified mash yielded 5.89%, v/v ethanol in a simultaneous saccharification and fermentation process using a yeast strain Saccharomyces cerevisae (SC‐39) at 35°C for 4 days. Removal of inhibitory substances from the fermenting broth through dialysis caused considerable increase in ethanol production.
Isolation of porcine adenovirus as a candidate of 5th serotype
Authors: Kadoi K. , Inoue Y. , Ikeda T. , Kamata H. , Yukawa M. , Iwabuchi M. , Inaba Y. 
Published: February 2007

AbstractA strain of cytopathic virus, named strain TG/K79, was isolated from the brain of a newborn piglet, pure Hampshire breed, which died shortly after birth. The physicochemical property of virus was considered to be that of the family Adenoviridae. A significant difference between our isolate and 4 reference porcine adenoviruses was demonstrated by cross‐seroneutralization testDifferences between TG/K79 and other porcine adenoviruses were also seen in electrophoretic patterns of viral DNA in agarose gel after digested by restiction endonucleases. Two SPF pigs, 2‐month‐old, experimentally infected via intranasal showed a fever and a hemorrhagic enteritis. A serological survey indicates that at least swine in the farm where the virus was isolated have been highly contaminated.
The fix Escherichia coli region contains four genes related to carnitine metabolism
Authors: Eichler Knut , Buchet Anne , Bourgis Fabienne , Kleber Hans‐Peter , Mandrand‐Berthelot Marie‐Andrée 
Published: February 2007

AbstractAnaerobic carnitine metabolism in Escherichia coli was recently shown to involve six genes organized in the cai operon and located at the first minute on the chromosome. The DNA sequence lying at the 5′ end of the cai locus was further investigated. It contains four open reading frames organized as an operon. In vivo overexpression of this DNA region revealed four polypeptides with apparent molecular masses of 27, 33, 45 and 6 kDa. These proteins displayed significant amino acid sequence homologies with polypeptides encoded by the fixABCX operons from Azorhizobium caulinodans and Rhizobium meliloti. The four ORFs were thus named fixABCX. The first two gene products were also found to share a high degree of sequence similarity with the subunits β and α, respectively, of mammalian electron transfer flavoproteins, suggesting a role for these proteins in a redox reaction. A singly polycistronic 5 kb mRNA transcript was detected in Northern blots under anaerobic conditions in the presence of DL‐carnitine. Expression of a fixA‐lacZ transcriptional fusion was induced by L(‐)‐carnitine and crotonobetaine but not by D(+)‐carnitine, γ‐butyrobetaine, glycinebetaine and choline as found previously for the carnitine pathway. Similarly, the fix operon was repressed by glucose and nitrate. Moreover, expression of the fix operon was induced by the global regulatory proteins CRP and FNR and repressed by the histone‐like protein H‐NS. All these regulatory proteins have been shown also to control expression of carnitine enzymes. Results from Northern blots and lacZ fusion studies indicate a common regulation of expression of fix and cai operons, which implies a physiological linkage between these two loci.
Proteolytic activity of Aeromonas caviae
Authors: Karunakaran T. , Devi B. G. 
Published: February 2007

AbstractAeromonas strains produce a variety of virulence factors including proteases. Studies on the kinetics of growth of Aeromonas caviae NRRL B‐966 and its proteases suggest that the proteolytic activities are produced throughout the growth phase, with peak level occurring at stationary phase. A. caviae synthesize both intracellular and extracellular proteases with the latter account for major portion of the total activity. Optimum pH for the A. caviae proteolytic activity is at 7.0. A. caviae produces a thermoresistant protease, whose activity is dependent on Mg++ and Ca++ ions. Inhibition of proteolytic activity by phenyl methyl sulfonyl fluoride suggest the presence of a serine protease in A. caviae. Nitrogenous compounds enhance the proteolytic activity while carbohydrates tested in this study inhibit the activity.
Biological treatment of distillery waste for pollution‐remediation
Authors: Fitzgibbon F. J. , Nigam P. , Singh D. , Marchant R. 
Published: February 2007

AbstractThe biological treatment of spent wash from molasses distilleries was investigated. Analysis of raw spent wash showed it to be a recalcitrant waste, with a high COD of 85,170 mg/l and containing inhibitory phenolic compounds. Reverse phase thin layer chromatography identified gallic and vanillic acid present in spent wash. The fungi Geotrichum candidum, Coriolus versicolor, Phanerochaete chrysosporium and Mycelia sterilia were screened for their ability to decolourize spent wash and to reduce the COD level. A 10 day pretreatment with Geotrichum candidum at 30°C resulted in reducing the COD by 53.17% and total phenols by 47.82%, enabling other bioremediating organisms to grow. Coriolus versicolor immobilized in a packed‐bed reactor reduced the COD of spent wash by a further 50.3%, giving an overall reduction in COD of 77% to 15,780 mg/l. A small amount of decolourization was achieved (4.2%), although the spent wash was still coloured. Present studies are encouraging and indicate that it is possible to bioremediate spent wash using a multi‐stage treatment process involving an intial pretreatment step with Geotrichum candidum.
Cometabolic degradation of o‐cresol and 2,6‐dimethylphenol by Penicillium frequentans Bi 7/2
Authors: Hofrichter Martin , Bublitz Friedemann , Fritsche Wolfgang 
Published: February 2007

Abstracto‐Cresol induced glucose‐grown resting mycelia of Penicillium frequentans Bi 7/2 (ATCC‐number: 96048) immediately oxidized o‐cresol and other phenols. After precultivation on glucose and phenol degradation started after a lag‐phase of 24 hours. Metabolites of o‐cresol metabolism were methylhydro‐quinone, methyl‐p‐benzoquinone, 2‐methyl‐5‐hydroxyhydroquinone and 2‐methyl‐5‐hydroxy‐p‐benzo‐quinone. The initial reaction is probably catalyzed by a NADPH dependent hydroxylase which is specific for o‐cresol. The metabolism of 2,6‐dimethylphenol (2,6‐xylenol) occurred via 2,6‐dimethylhydroqui‐none, 2,6‐dimethyl p‐benzoquinone, 2,6‐dimethyl‐3‐hydroxyhydroquinone, 2,6‐dimethyl‐3‐hydroxy‐p‐benzoquinone and 3‐methyl‐2‐hydroxybenzoic acid.
Isolation of dimeric nonactic acid from the nonactin‐producing Streptomyces spec. JA 5909‐1
Authors: Fleck Werner F. , Ritzau Michael , Heinze Stephan , Gräfe Udo 
Published: February 2007

AbstractThe formation of possible intermediates of nonactin (I) biosynthesis by Streptomyces spec. JA 5909‐1 was investigated. In addition to monomer nonactic acid (II), the dimeric nonactic acid (III) was isolated suggesting that III could be an intermediate of nonactin biosynthesis. The structure of III was settled by electrospray mass‐spectrometry and high‐field FT‐NMR methods. III displays no antibacterial and antifungal activities supporting the view that cation complex formation by nactin‐type antibiotics requires the entire macrotetrolide ring.
Enhanced excretion of intermediates of aromatic amino acid catabolism during chlorophenol degradation due to nutrient limitation in the yeast Candida maltosa
Authors: Hammer Elke , Kneifel Helmut , Hofmann Klaus , Schauer Frieder 
Published: February 2007

AbstractIncubation of phenol‐induced cells of the yeast Candida maltosa SBUG 700 with mono‐ and dichlorophenols resulted in the formation of metabolites of the substrates and of further metabolites not related to the degradation pathway of the substrates. These additional compounds, identified as 4‐hydroxyphenylacetic acid (4‐HPA), phenylacetic acid (PA), indolylacetic acid (IA) and indolylethanol (IE) by means of HPLC and GC/MS, were not excreted in incubation experiments with glucose.The excretion of these metabolites of aromatic amino acid metabolism is not caused by toxic effects of the phenol derivatives, but seems to be a result of carbon and nitrogen starvation of yeast cells.
Unusual resistance and acquired tolerance to cadmium chloride in Enterococcus faecalis
Authors: Paplace Jean‐Marie , Boutibonnes Philippe , Auffray Yanick 
Published: February 2007

AbstractEnterococcus faecalis exhibits an extremely high natural resistance to cadmium which can be even raised by a conditioning treatment at a lower cadmium concentration as well as by a previous exposure to a sublethal temperature. By contrast, thermotolerance is not significantly induced by previous exposure to low cadmium concentration. The synthesis of several proteins is markedly enhanced by a low concentration of the chemical agent.
Analysis of the PHA granule‐associated proteins GA20 .and GA11 in Methylobacterium extorquens and Methylobacterium rhodesianum
Authors: Föllner Christina G. , Madkour Mohamed , Mayer Frank , Babel Wolfgang , Steinbüchel Alexander 
Published: February 2007

AbstractElectrophoretic analysis of the proteins bound to poly(3‐hydroxybutyric acid), PHB‐, granules in Methylobacterium extorquens, M. rhodesianum as well as the PHB‐leaky mutants Mu 1 and Mu 11, which were isolated from the latter, resulted in two dominant low‐molecular weight proteins, which were referred to as GA 11 and GA20. After purification of these proteins antibodies against the GA11 and GA20 protein of M. extorquens were obtained. Both proteins bound to the surface of PHB granules as revealed by immunoelectron microscopy of whole cells of M. extorquens and M. rhodesianum. With cells of the PHB‐leaky mutants Mu 1 and Mu 11 no specific labeling was observed. The N‐terminal amino acid sequences of the GA11 and the GA20 protein were determined. We found significant homologies between the sequences of the investigated strains. The use of oligonucleotide probes based on the N‐terminal sequences of the GA20 protein from M. rhodesianum to identify the corresponding structural genes in various genomic libraries failed.
Degradation of dimeric lignin model compounds by aerobic bacteria isolated from the hindgut of xylophagous termites
Authors: Kuhnigk Thomas , König Helmut 
Published: February 2007

AbstractThe capability of the intestinal flora from the gut of xylophagous termites of degrading lignin model compounds was investigated. Different dimeric lignin model compounds‐degrading bacteria were obtained from the hindgut flora of Mastotermes darwiniensis FROGGATT, Reticulitermes santonensis FEYTAUD, Nasutitermes nigriceps HALDEMAN and Zootermopsis angusticollis HAGEN. In the presence of oxygen dimeric model compounds were degraded by all isolates. This indicates that the hindgut flora of termites is basically able to produce substrate for their host from aromatic extractives of wood.
Degradation of phenanthrene and pyrene by Nematoloma frowardii
Authors: Sack Ute , Hofrichter Martin , Fritsche Wolfgang 
Published: February 2007

AbstractThe white‐rot fungus Nematoloma frowardii was examined for the ability to degrade [ring U‐14C]‐phenanthrene and [4,5,9,10‐14C]pyrene in liquid and solid (straw) cultures in a period of 63 days. 3.2% phenanthrene and 8.6% pyrene were mineralized to 14CO2 in liquid cultures, respectively. A considerable higher mineralization of 11.2% (phenanthrene) and 46.5% (pyrene) was detected in straw cultures. Metabolites were identified by their UV absorption spectra. N. frowardii transformed phenanthrene to phenanthrene 9,10‐dihydrodiol. Pyrene 4,5‐dihydrodiol was identified as major metabolite in pyrene degradation.