bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pseudomonas acidovorans: a bacterium capable of mineralizing 2‐chloroaniline
Authors: Hinteregger Christel , Loidl Michael , Streichsbier Franz 
Published: February 2007

AbstractProlonged adaptation of Ca‐alginate immobilized cells of Pseudomonas acidovorans CA28 to a mixture of 3‐chloroaniline (3‐CA)1) and 2‐CA and subsequently to 2‐CA as sole substrate led to the isolation of another strain, termed CA50 with the additional capability of utilizing 2‐CA as sole source of carbon, nitrogen, and energy. Batch‐degradation of 190 mg/l of 2‐CA at pH 6.1 by this newly isolated strain was achieved within 3 days, at higher concentrations up to 0.6 g/l increasing lag‐phases and degradation periods were observed. Except chloride and ammonium no further metabolites were detectable in the medium. Mineralization of 2‐CA proceeds via the modified ortho‐cleavage pathway as demonstrated by the presence of catechol 1,2‐dioxygenase (C120) activity, which is characterized by its substrate specificity and elution behaviour on DEAE‐cellulose.
Principal characteristics of α‐galactosidase from Leuconostoc mesenteroides subsp. mesenteroides
Authors: Huang D. Q. , Prévost H. , Diviès C. 
Published: February 2007

Abstractα‐Galactosidases (α‐gal) from six strains of Leuconostoc mesenteroides subsp. mesenteroides, which were isolated from four different ecological niches, have been characterized. The enzymes have an optimum pH ranging from 5.5 to 6.4. Strain 19A possesses a pH optimum close to neutral. The optimum temperature varied with the strains, ranging from 37 to 43 °C. The Km values of the enzymes for substrate p‐nitrophenyl‐α‐D‐galactopyranoside (PNPG) varied from 2.15 to 22.70 mM. α‐Gal from strain 23A had the lowest affinity for substrate PNPG. An increase of the affinity for PNPG in the presence of 10 mM lactose was observed for strains 6M, 19A, 23A, 19M, while this higher affinity for PNPG was also observed in the presence of 10 mM galactose for strains 6M, 23A, 19M. The activation energy of the enzyme from different strains was calculated to be about 62.9–72.8 kJ/mol. Ca2+ ions have a strong inhibitive effect on the enzyme activity. Appearance of α‐gal activity band and protein profiles under the same conditions of SDS‐PAGE allowed an estimation of the apparent molecular weight of α‐gal to be at about 175,000.
Natural occurrence of mycotoxins in broad bean (Vicia faba l.) seeds and their effect on Rhizobium‐legume symbiosis
Authors: Mahmoud A.‐L. E. , Abd‐Alla M. H. 
Published: February 2007

AbstractSeeds of faba bean cultivar Giza 3 were screened for natural presence of mycotoxins. Eleven out of 100 samples were contaminated. Aflatoxins B1 and B2 were found in 7 samples while aflatoxins B1, B2, G1 and G2 and ochratoxin A were each detected twice in separate samples. Mycotoxins at concentrations of 100 or 200 μg kg−1 soil significantly decreased nodule number, nodule fresh weight and total nitrogenase activity, leading to reductions in dry matter accumulation and nitrogen yield of the bean. Mycotoxins also suppressed specific nitrogenase activity. NADH‐dependent glutamate dehydrogenase (NADH‐GDH) as well as glutamate synthase (NADH‐GOGAT) activities. In addition, mycotoxins inhibited synthesis of leghaemoglobin, carbohydrated and protein in the nodule cytosol. Of the mycotoxins tested, aflatoxin B1 was the most toxic. The decline in nitrogenase activity and total N concentration in the plants could be attributed to mycotoxins interference with normal nodule physiology and function.
Microbial degradation of phloroglucinol and other polyphenolic compounds
Authors: Armstrong S. M. , Patel T. R. 
Published: February 2007

AbstractBiodegradation of phloroglucinol (1,3,5‐trihydroxybenzene) and other polyphenolic compounds by microbes may occur by aerobic and anaerobic metabolic pathways. Aerobic microbes may initiate the mineralization of phloroglucinol or other polyphenolics by either a reductive pathway, epoxide formation, or a specific hydroxylating mechanism. Cleavage of the various intermediates of phloroglucinol and polyphenolic degradation may occur by intradiol and extradiol mechanisms. The reductive pathway in contrast to other mechanisms utilized by aerobic microbes, seems both cumbersome and energy wasteful. The degradation of lignin and its associated phenolics follows an enzymatic combustion process which resembles a nonspecific enzyme‐catalyzed burning. Anaerobic mineralization of phloroglucinol and its associated polyphenolics by several microbes seems to favour the reductive formation of a dihydrophloroglucinol (1,3‐dioxo‐5‐hydroxycyclohexane), which is cleaved by a specific hydrolase. Mineralization of numerous other polyphenolic compounds by anaerobes seems to utilize phloroglucinol as a central metabolite.
Modulation of the spc operon affects growth and protein secretion in Bacillus subtilis
Authors: Breitling Reinhard , Schlott Bernhard , Behnke Detlev 
Published: February 2007

AbstractA proximal segment of B. subtilis sec Y gene was placed under the control of the inducible spac promoter Lac repressor system. This fusion was integrated into the chromosomal spc operon of B. subtilis via Campbell‐like reciprocal recombination. The growth of the resulting strain was strongly IPTG dependent. With staphylokinase and α‐amylase as reporter proteins it was found, that the protein secretion capacity of this strain was correlated to the conditions of repression or induction of the chromosomal spac promoter.
Utilization of beet molasses for riboflavin production by Mycobacterium phlei
Authors: Ghozlan H. A. 
Published: February 2007

AbstractMycobacterium phlei was tested for its ability to utilize beet molasses as the sole carbon source and produce riboflavin. The crude beet molasses was analyzed and treated in various ways to reduce its heavy element content and to remove the muddy residue. Promising amounts of riboflavin were produced when the organism was cultivated on decationized (resin‐treated) beet molasses. The highest vitamin productivity was achieved by incubating the inoculated medium containing 9% molasses and initially adjusted to pH 6 under shacked condition for 6 days in the dark.
Antibacterial activity of three Leuconostoc strains isolated from vacuum‐packaged processed meats
Authors: Papathanasopoulos Maria Antonia , Hastings John Waugh , Holy Alexander Von 
Published: February 2007

AbstractOne hundred and fifty lactic acid bacteria (LAB) isolated from vacuum‐packaged processed meats were screened for antagonistic activity against various food spoilage microorganisms and foodborne pathogens. Nineteen strains produced bacteriocins active against closely related LAB and Listeria strains. Leuconostoc carnosum (LA54a and TA26b) and Leuconostoc mesenteroides subspecies dextrancum (TA33a) produced bacteriocins that were susceptible to proteolytic enzymes, but not to catalase, lysozyme or chloroform. They were heat stable up to 100 °C for thirty minutes at pH 2 to 7, and exerted a bacteriolytic effect. Bacteriocin production by all Leuconostoc strains was growth associated, occurring at incubation temperatures of 0 °C to 30 °C and initial medium pH 4.5 to 7.5. Probing of plasmid DNA from the three Leuconostoc strains with an oligonucleotide probe homologous to the nucleotide sequence of leucocin A‐UAL 187 indicated plasmid‐mediated bacteriocin production. Homology of the three Leuconostoc bacteriocin‐coding genes to the amino‐terminal end of the leucocin A‐UAL 187 gene from Leuconostoc gelidum UAL 187 is therefore suggested. This evidence implies that all three Leuconostoc strains produce type 2, Listeria active bacteriocins.
Isolation of plasmid pRLI from Arthrobacter oxydans 317 and demonstration of its role in steroid 1 (2)‐dehydrogenation
Authors: Sarman Utpal , Roy Monoj K. , Singh H. Devendra 
Published: February 2007

AbstractArthrobacter oxydans 317 capable of complete degradation of β‐sitosterol harbours two plasmids ‐pJLI and pRLI. Standard plasmid isolation methods can easily detect pJLI but not pRLI. The latter plasmid was isolated by a mild procedure using α,α′‐dipyridyl as lytic agent and separated from pJLI by agarose gel electrophoresis using the technique of electro elution into throughs. It's molecular weight was found to be about 3.5 kilo base (kb) pRLI was introduced into the plasmid cured A. oxydans 317 AL. Through genetic transformation using protoplasts of the recepient strain, a transformant strain A. oxydans 317 ALT bearing only pRLI plasmid was obtained. The transformant strain was unable to grow on 4‐androstene‐3, 17‐dione (AD) and 1,4‐androstadiene‐3,17‐dione (ADD) as sole carbon source but a modest growth was observed on 9α‐hydroxy‐4‐androstene‐3, 17‐dione (9α‐hydroxy AD) indicating the ability for steriod 1 (2)‐dehydrogenation and a lack of the capacity for α,α‐hydroxylation. The strain was able to form ADD from AD, and 1 (2)‐dehydrogenation of 3‐oxochol‐4‐en24‐oic acid from β‐sitosterol. Direct estimation of steroid (1 (2)‐dehydrogenase activity showed that the transformant strain and parent strain containing pRLI had high enzyme activity where as strains lacking in this plasmid had negligible enzyme activity. It was concluded that pRLI is responsible for steroid 1 (2)‐dehydrogenation in A. oxydans 317.
Role of glutamine synthetase activity in the urea regulation of heterocyst and nitrogenase formation in the cyanobacterium Anabaena cycadeae
Authors: Singh Surendra , Bisen P. S. 
Published: February 2007

AbstractGrowth and urea regulation of heterocyst and nitrogenase formation have been studied in the diazotrophic cyanobacterium Anabaena cycadeae and its glutamine auxotrophic mutant strain lacking glutamine synthetase (GS) activity. The parent strain having normal GS activity utilized urea as sole nitrogen source without producing N2‐fixing heterocysts. In contrast, the mutant strain lacking GS activity could not utilize urea as sole nitrogen source although similar to the parent strain it lacked N2‐fixing heterocysts in urea‐medium. Both parent and mutant strain showed high levels of urea uptake and urease activity in the presence and absence of a GS inhibitor, l‐methionine‐dl‐sulphoximine (MSX). Urea‐dependent NH production by MSX‐untreated cells was only confined to the mutant strain lacking GS activity whereas the parent strain having normal GS activity produced NH only in the presence of MSX. These results suggest that (i) GS is the sole NH assimilating as well as glutamine‐forming route in heterocystous N2‐fixing cyanobacteria; (ii) while GS activity is necessarily required for the assimilation of urea as sole nitrogen source, it is however, not required for the urea inhibition of heterocysts and nitrogenase formation; (iii) that NH resulting from the hydrolysis of urea and not GS‐mediated pathway of NH assimilation appears to be the initial repressor signal for heterocysts and nitrogenase formation; and (iv) GS does not control the formation of N2‐fixing heterocysts, urea uptake and urease activity systems.
Xylitol formation by Candida guilliermondii in media containing different nitrogen sources
Authors: Silva Silvio S. , Mancilha Ismael M. , Queiroz Maurício A. , Felipe Maria G. A. , Roberto Ines C. , Vitolo Michele 
Published: February 2007

AbstractThe xylose conversion into xylitol by Candida guilliermondii was evaluated in semi‐synthetic media supplemented with different nitrogen sources in a ratio C/N equal 25.6. It was noticed that the xylitol yield was around 80% and also that the type of nitrogen source did not influence this bioconversion.
Glutamic acid synthesis from methanol: Theoretical considerations
Authors: Ackermann Jörg‐Uwe , Babel Wolfgang 
Published: February 2007

AbstractTo determine to what extent methanol in addition to the commonly used glucose is an attractive alternative feedstock for glutamic acid production, a comparative theoretical consideration of possible yields is given. Methanol can be assimilated by bacteria via three different metabolic pathways. With regard to the corresponding energy balance equations the overproduction process is either energy‐deficient, energy‐neutral or energy‐excess. The theoretical maximum yields of glutamic acid synthesis with methanol as a substrate are not substantially lower than based on glucose. In one case the value is even higher. From the aspect of possible yields methanol would not be less convenient than glucose and the serine pathway seems to be the most suitable one for the synthesis of glutamic acid.
Influence of growth rate and nutrient limitation on monobactam production and peptidoglycan synthesis in Pseudomonas aeruginosa
Authors: Allison D. G. , Nolan R. D. 
Published: February 2007

AbstractThe effects of growth rate and nutrient limitation on monobactam production, peptidoglycan content and mean cell length in Pseudomonas aeruginosa was studied using continuous culture techniques. All three parameters increased progressively with growth rate, a greater response being shown under carbon limitation compared to that occurring under nitrogen limiting conditions. Interestingly, monobactum production mirrored peptidoglycan synthesis. In addition, the monobactam exhibited a broad range of antibacterial activity and bound preferentially to PBP 1A in the producing organism. Moreover, addition of the monobactam to a growing culture inhibited cell wall synthesis. These results are discussed in relation to the control and regulation of peptidoglycan synthesis.
Action of carbamate biocides on sterols, gibberellin and aflatoxin formation
Authors: Hasan H. A. H. 
Published: February 2007

AbstractAn interrelationship between primary and secondary metabolites of a toxigenic mould(Aspergillus parasiticusvar.globosusIMI 120920) was obtained in liquid broth containing various concentrations of dithaneZ‐78 and propoxur. The results show that a stimulatory response was recorded in gibberellin, protein, sterol and aflatoxin yield in cultures treated with 15, 30, 50 and 100 ppm a.i. of dithane Z‐78. On the other hand, propoxur reduced the yield of gibberellin, amino acids, protein, sterol and aflatoxin. In comparison to its effect on the mycelial growth, gibberellin and aflatoxin activity is inhibited more severly than dry weight increase, thus leading to the assumption that there is a specific effect of the inhibitor on both gibberellin and aflatoxin synthesis.
Development of an inexpensive legume‐Rhizobium inoculation technology which may be used in aerial seeding
Authors: Jha Prakash K. , Nair Suresh , Babu C. R. 
Published: February 2007

AbstractEncapsulation of seeds with alginate entrapped rhizobia (AER) bead has been developed as a new seed‐applied inoculum technique for utilizing legume‐Rhizobium symbiosis for the management and protection of natural ecosystems. Alginate beads trapped water and immobilized rhizobia which ensured germination of seeds and nodulation of seedlings. Incorporation of a synthetic polymer, Jalshakti, in alginate beads did not enhance symbiotic nitrogen fixation but sufficient number of rhizobia remain viable in them even after 30 weeks of storage reflecting suitability of these materials as carriers for rhizobia. Plant cultures raised from these beads were similar to or even better than the inoculated controls in symbiotic parameters indicating the effectiveness of seed‐applied inoculum technique. Pelleting of seeds with these polymers after coating with gum arabic lead to substantial reduction in symbiotic association and viability of rhizobia. Experiments involving two legume‐Rhizobium associations indicated that the encapsulation of seed with AER bead is a cheap, inexpensive and effective inoculation technique which may be used in aerial seeding.
A revised map location for the histidine utilization genes in Pseudomonas putida
Authors: King Robin S. , Sechrist Lynne L. , Phillips Allen T. 
Published: February 2007

AbstractThe histidine utilization genes hutH and hutU of Pseudomonas putida ATCC 12633 have been mapped by interrupted mating and transduction to a location at approximately 43 minutes on the chromosome, closely linked to ser‐800 and met‐400 markers previously shown to be at 46 and 42 minutes, respectively. Since restriction enzyme mapping and cloning results have established that all genes associated with the hut pathway are contiguous, earlier maps of this strain which place these genes near 10 minutes on the chromosome in a superoperonic catabolic cluster are in error.
Loss of the TOL meta‐cleavage pathway functions of Pseudomonas putida strain PaW1 (pWW0) during growth on toluene
Authors: Brinkmann Ulrich , Ramos Juan L. , Reineke Walter 
Published: February 2007

AbstractA derivative of Pseudomonas putida strain PaW1 bearing the TOL plasmid pWW0 was isolated from a culture which has grown unlimited on toluene. In contrast to the parent strain PaW1, the derivative, strain CG220, is unable to grow with xylenes and toluates, while toluene and benzoate served as substrates. Strain CG220 had a remarkable growth advantage against the wild type when grown with toluene. Biochemical analysis showed that in strain CG220 toluene was metabolised through the TOL plasmid upper pathway to benzoate and the latter to amphibolic intermediates by the chromosomal encoded ortho‐cleavage pathway. No activities of the TOL plasmid encoded toluate dioxygenase and catechol 2,3‐dioxygenase were detectable in strain CG220. No reversion of strain CG220 to growth with xylenes or toluates was observed. Hybridisation experiments with TOL plasmid‐derived gene probes and oligonucleotides revealed that genes xy/Y to xy/G were absent, while xy/X and xy/K were still present.
Keratinophilic fungi in soils of Yemen Arab Republic
Authors: El‐Said A. H. M. 
Published: February 2007

AbstractThirty‐six species belonging to 15 genera of keratinophilic fungi were collected from 50 soil samples gathered from different places of Yemen by using hair fragments as baits at 28 °C. Six species of true dermatophytes were collected:Arthroderma lenticulare(=Trichophyton terrestre), Trichophyton mentagrophytes, T. equinum, T. rubrum, T. soudanenseandMicrosporum gypseum. Numerous Keratinophilic fungi were isolated namely:Aphanoascus terreus(=Chrysosporium indicum), Aphanoascus species( =C. tropicum), A. fulvescens( =C. keratinophilum), Chrysosporium pannicola, C. pruinosum, C. carmichaelii, C. lucknowense, C. xerophilum, C. asperatum, Athroderma cuniculi( =C. anamorphofArthroderma cuniculi),A. curreyi( =C. anamorphofArthroderma curreyi) andPectinotrichum Ilanense( =C. anamorphofPectinotrichum Ilanense). The commonest saprophytes in order of frequency were member of the generaAspergillus, Alternaria, Penicillium, Rhizopus, Cunninghamella, Fusarium, UlocladiumandMacrophomina.
Characterization of a Tn925‐induced mutant of Staphylococcus aureus altered in exoprotein production
Authors: Giraudo Ana T. , Martínez Gabriela L. , Calzolari Aldo , Nagel Rosa 
Published: February 2007

AbstractAn insertional mutant was isolated from a bovine Staphylococcus aureus strain after membrane‐mating with a Streptococcus faecalis strain carrying conjugative plasmid pCF10: : Tn925. This mutant, designated RC128, showed enhanced production of α‐hemolysin and proteases and decreased production of coagulase, extracellular protein A, DNase, lipase and δ‐hemolysin. No difference was found in the production of β‐hemolysin. Both, Southern blot analysis and transfer of the pleiotropic mutant phenotype by transduction, indicated that the mutation was originated from a single insertion of transposon Tn925. The LD50 determined by intraperitoneal administration in mice showed that mutant RC128 was slightly less virulent than its parental strain.
Role of phenolic substances in pathogenesis of soft rot diseases
Authors: Khare V. , Mehta P. , Kachhwaha M. , Mehta A. 
Published: February 2007

AbstractPhomopsis sapotae and P. psidii are known to cause severe fruit rot diseases of Achras sapota and Psidium quajava fruits respectively. Among all tested phenolic compounds, α‐naphthol (50 ppm) and guaiacol (250 ppm) caused complete inhibition of mycelial growth of Phomopsis sapotae and P. psidii. Achras sapota and Psidium quajava fruits treated with α‐naphthol (50 ppm) and guaiacol (250 ppm) did not show any disease symptoms and hence complete inhibition of polygalacturonase, pectinmethylgalacturonase and cellulase enzyme was recorded in both the fruits. Pyrocatechol and phloroglucinol were least inhibitory in checking the mycelial growth, rot development and enzyme secretion in both the tested fruits. Generally these parameters were decreased by increasing the concentration of each phenolic compound in both the cases.
Influence of some non‐halogenated aromatics on 2,4‐D assimilation by a microbial consortium
Authors: Müller R. H. , Babel W. 
Published: February 2007

AbstractA microbial consortium capable of converting 2,4‐D with a maximum rate of 0.18 h−1 under chemostatic conditions was shown to be unable to further utilize this compound after nonchlorinated aromatics were simultaneously supplied. After a long term cultivation on aniline and 2,4‐D under chemostatic conditions, 2,4‐D remained almost unmetabolized and the culture could not be reactivated to use 2,4‐D as a sole source of carbon and energy. However, phenol pulses did not disturb growth on 2,4‐D when the latter was supplied in a carbon substrate‐limited manner at a rate lower than that used in the precultivation phase. Phenol even remained unmetabolized after one day of treatment. Wash‐in of phenol to a culture growing on an excess of 2,4‐D did not lead to a disturbance of growth either, but to a sequential consumption of both. These results are discussed in terms of metabolic incompatibility in the conversion of chlorinated and non‐chlorinated aromatics and regulatory threshold concentrations.
A new microbial isoquinoline iron chelator from Streptomyces spec. 2002‐104
Authors: Gräfe Udo , Ritzau Michael , Ihn Wolfgang , Möllmann Ute , Fleck Werner F. , Groth J. , Reissbrodt Reinhardt 
Published: February 2007

Abstract2‐N‐hydroxy‐3,4‐dihydro‐isoquinoline‐1‐one (C9H9NO2, 1) was isolated as a new naturally occurring iron chelator from cultures of Streptomyces spec. 2002‐104 in the course of a screening for new iron chelating compounds. The structure was solved by high resolution MS and NMR investigations.
Catabolite repression of cellulase biosynthesis in Streptomyces albaduncus
Authors: Harchand R. K. , Singh S. 
Published: February 2007

AbstractThe cellulase complex of S. albaduncus was found to undergo catabolite repression in the presence of glycerol accompanied by a decrease in the pH of the medium. The results of the experiments conducted at two different initial pH of the medium suggested that pH effect as well as proteases were involved in the inactivation of glucanases (exoglucanase and endoglucanase) whereas β‐glucosidase inactivation was solely due to ‘pH effect’. It was also apparent that pH change followed by the addition of glycerol caused alterations in protease activities as well as pattern of their production.
Osmotolerant yeasts isolated from Tokaj wines
Authors: Miklós Ida , Sipiczki M. , Benko Z. 
Published: February 2007

AbstractYeasts growing in “Tokaj Aszu” wine and in “Aszu essence” were isolated and characterised. They proved to be physiological races of Saccharomyces cerevislae and showed high osmotolerance, which was an inherited feature rather than the result of adaptation. No correlations were found between the osmotolerance and the ethanol tolerance or the cell size and morphology. Yeasts in “Aszu essence” are usually undesirable contaminants that impair the quality of the essence. The isolate characterized in this work exhibited physiological parameters very similar to those of the “Tokaj Aszu” strain, which make it a potent competitor of other yeasts in Aszu fermentation. However, the high termo sensitivity of its cells offers a possibility to eliminate them selectively.