bluuebunny/crossref_metadata_2025 huggingface dataset:
A correlation with type of sulfonamide resistance gene in Escherichia coli and synergy between trimethoprim and sulfamethoxazole
Authors: Valentine Carrie R. , Hawk James M. , Christian Mary M. , Youmans Roger W.
Published: February 2007

Plasmids carrying type I or II sulfonamide‐resistance (Sur) genes were evaluated for their effect on synergy between trimethoprim (Tmp) and sulfamethoxyzole (Smx) in E. coli. Strain J53 containing each of three plasmids (R1, pSa, and R388) with the type I Sur gene displayed a synergistic response to Tmp/Smx; strain LE392 containing a plasmid (RSF1010) with the type II Sur gene displayed no synergy. The difference in synergy between type I and type II Sur genes might be explained by the difference in amount of resistant enzyme produced.
Metabolism of gallate in Penicillium simplicissimum
Authors: Patel T. R. , Hameed Nuzhat , Armstrong Stephen
Published: February 2007

The pathway for the degradation of gallate (3,4,5‐trihydroxybenzoate) by a new strain of Penicillium was examined by in vivo and in vitro cell‐free systems. The organism was identified as P. simplicissimum (OUD THOM. It grew optimally at pH 5.5 and 27 °C, with 11.75 mM (0.2%) gallate added to the basal salt media. Mycelia grown on gallate accumulated protocatechuate in the medium, and had inducible activity for protocatechuate 3,4‐dioxygenase as determined by spectrophotometric and oxygen electrode studies. A NADPH‐dependent reductase in the cell‐free extract reduced gallate to dihydrogallate. Maleylacetate reductase was also detected in the gallate induced cell‐free extract, while β‐ketoadipate was detected as the product produced. The possible steps in the degradation of gallate are discussed.
Fungal contamination, natural occurrence of mycotoxins and resistance for aflatoxin accumulation of some broad bean (Vicia fabaL.) cultivars
Authors: Saber Sabah M.
Published: February 2007

Using glucose‐CZAPEK's and 10% NaCl glucose‐CZAPEK's agar media incubated at 28 ± 2 °C, nine genera and 18 species were identified from 10 different cultivars seed of broad bean.AspergillusandPenicilliumwere the most common genera on the two types of media used. The most common fungal species wereAspergillus flavus, A. niger, A. tamariiandPenicillium chrysogenum.

Thin‐layer chromatographic analysis indicated that seeds of one cultivar only was naturally contaminated with aflatoxins B1, B2, G1and G2. Nine mycotoxin‐free cultivars of broad bean were examined for resistance or susceptibility for aflatoxin production when inoculated byAspergillus flavusIMI 89717. Results obtained revealed that seeds of two cultivars were highly resistant, two cultivars showed partial resistance and the remaining were susceptible to the establishment ofA. flavusand aflatoxin accumulation.

The results did not show any relationship between morphological characters (olour, shape and size) and the amount of aflatoxin produced on the different broad bean seed cultivars. Also the results reveal absence of significant variation in the total nitrogen of the highly susceptible, partially resistant and highly resistant groups of broad bean seeds examined. Mean values of calcium, total phosphate and potassium of both seed coat and seed kernel of the susceptible seeds were low as compared to those of partially and highly resistant seed cultivars. The susceptible seeds contained higher levels of magnesium, zinc and sodium while the resistant seeds contained lower ones.
Cellulase from Trichoderma isolate
Authors: Ali Md. Showkat , Akhand Anwarul Azim
Published: February 2007

A new mesophilic Trichoderma isolate produced cellulases during growth on water hyacinth. Optimum cultural conditions for maximum enzyme production were: water hyacinth 0.25%, NH4NO3 0.2%, Tween 80.2%, 6 day cultivation at 28–30 °C. Partially purified cellulases from this organism displayed activity optima at pH 3–4 and 50–60 °C. The enzymes were stable at pH 3–6 and temperature upto 60 °C. Fe2+ had the most stimulating effect on cellulases activities amongst many metal ions tested.
Characterization of root‐nodule bacteria indigenous in the salt‐affected soils of Egypt by lipopolysaccharide, protein and plasmid profiles
Authors: Zahran Hamdi H.
Published: February 2007

Some characteristics of thirty isolates of root‐nodule bacteria, indigenous in the salt‐affected soil of Egypt, were studied. To recognize different isolates of these bacteria, the electrophoretic pattern of plasmids and of whole cell lipopolysaccharides (LPS) and proteins were analysed and compared using agarose gel electrophoresis (AGE) and sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE), respectively. The bacteria showed patterns of LPS, protein and plasmid which varied among isolates of different plant species as among isolates of a single plant species. Based on LPS and protein profile analysis, isolates from root‐nodules of broadbean and lupin plants were more diverse than isolates from root‐nodules of berseem plant. Root‐nodule bacteria of lupin and berseem were also less diverse than root‐nodule bacteria of broadbean when compared on the basis of plasmid profiles. This result indicate that root‐nodule bacteria of broadbean may have higher surviving ability in the salt‐affected soil. Most isolates of the root‐nodule bacteria synthesized specific LPS (smooth, ladder‐like type) and protein, which were different from LPS and protein of other well‐known (recognized) Rhizobium species. These specific forms of LPS and protein could be a prerequisite for the bacterial isolates to tolerate salt stress conditions of the salt‐affected soils.
Naphthalene‐anthracene‐utilizing microorganisms
Authors: Bagy M. K. , Shoreit A. A. M. , Hemida S. K.
Published: February 2007

Oil‐polluted freshwater samples collected from Assiut oil company, Egypt, were screened for hydrocarbon‐utilizing microorganisms (bacteria and fungi). Two hydrocarbons (naphthalene and anthracene) were used as a sole source of carbon.

Most Probable Number (MPN) technique was used to determine naphthalene and anthraceneutilizing bacteria. Micrococcus, Corynebacterium, Nocardia and Pseudomonas were recovered on basal medium supplemented with the hydrocarbons. Numbers of bacteria decreased as the pollution in water increased. Eleven species and 1 variety belonging to 8 terrestrial fungal genera were collected from oil polluted water on naphthalene or anthracene modified CZAPEK agar medium. Aspergillus (A. flavus var. columnaris) and Scopulariopsis (S. brumptii) were the most prevalent genera. 75.4 and 24.6% of total bacterial isolates utilized naphthalene and anthracene with different ranges of turbidity, respectively.
Role of plasmid pJL1 of Arthrobacter oxydans 317 in the degradation of β‐sitosterol
Authors: Dutta Ranjit K. , Roy Monoj K. , Singh H. Devendra
Published: February 2007

Arthrobacter oxydans 317 is a plasmid (pJL1)‐harbouring organism capable of complete degradation of β‐sitosterol, 4‐androstene‐3,17‐dione (AD) and 1,4‐androstadiene‐3,17‐dione (ADD). Plasmid‐cured strain A. oxydans 317 A1 obtained by treatment of A. oxydans 317 with sodium dodecylsulphate (DUTTA et al. 1989) is capable of only partial degradation of β‐sitosterol side chain and incapable of utilizing AD and ADD. Conjugation experiments were carried out using A. oxydans 317 A1 as the recipient and A. oxydans 317 as the donor of pJL1 plasmid. A transconjugant strain A. oxydans 317 TC containing pJL1 plasmid was obtained. The transconjugant was able to form 9 α‐hydroxy‐4‐androstene‐3,17‐dione (9α‐hydroxy AD) from β‐sitosterol and AD, and to utilize ADD for growth but it could not convert AD to ADD. It was proposed that pJL1 is involved in the conversion of 3‐oxochol‐4‐en‐24‐oic acid to AD and in the 9α‐hydroxylation of the steroid nucleus but it is not connected with 1,2‐dehydrogenation, a critical reaction step in steroid ring opening.
Role of NH or NO on release of soluble phosphate from hydroxyapatite by Rhizobium and Bradyrhizobium
Authors: Halder A. K. , Banerjee A. , Mishra A. K. , Chakrabartty P. K.
Published: February 2007

Capability of strains of Rhizobium and Bradyrhizobium to solubilize phosphate was determined in a defined medium containing hydroxyapatite as source of insoluble phosphate and (NH4)2SO4 or KNO3 as nitrogen source. Phosphate solubilization was found to be directly related to reduction of medium pH during growth of the strains. In general, presence of NH in the medium caused higher solubilization of phosphate by the strains as compared to the presence of NO as nitrogen source. The strain R. leguminosarum bv. viccae BICC 635 was the only exception which solubilized comparable amount of phosphate in medium containing either (NH4)2SO4 or KNO3. It appears, that the strains employ two different mechanisms for phosphate solubilization. One of the mechanisms relies upon the presence of NH in the culture and the other is independent of it. The strains could be divided into two groups, high‐ and low solubilizers based on their performances of phosphate solubilization.
Mitotically unstable polyploids in the yeast Pichia guilliermondii
Authors: Klinner U. , Böttcher F.
Published: February 2007

Attempts to obtain triploids or tetraploids of P. guilliermondii by sexual hybridization led to mitotically stable hybrids. However, their DNA content per cell was not higher than in diploids. The results of random spore analysis demonstrate that these hybris were in fact aneuploids which obviously suffered drastic chromosome losses immediately after mating. This phenomenon could have been caused either by aneuploidy already present in the parental strains or it might have been due to a general inability of P. guilliermondii to maintain a polyploid genome.
A simple screening procedure for microbial phase‐transfer mediators conveying anions
Authors: Stengel C. , Reinhardt G. , Gräfe U.
Published: February 2007

The conveyance of methylorange (helianthin) anion from a weakly acidic aqueous solution to a toluene layer was taken as a measure for the presence of anionophoric metabolites in microbial culture extracts mediating the transfer of amphiphilic anions from the water phase to an organic solvent. The presence of lipophilic amines such as pamamycin in microbial extracts thus could easily be detected by a directed screening procedure for anionophoric compounds. The efficiency of the screening procedure was demonstrated both with purified antiobiotics (pamamycin, a dimethylamino subunit of pamamycin, turimycin) and extracts from a large collection of Streptomyces strains.
Fate of the subapical cell in Streptomyces granaticolor mycelia
Authors: Kretschmer S.
Published: February 2007

In stained Streptomyces granaticolor mycelia the fate of the subapical cell (c2) formed periodically after each septation of the apical cell (c1) was analzyed. From the time of birth of c2, the intervals until the starts of first and second branching, the doubling of length by branch growth, and septation were determined. Since five cultures grown at different growth rates were used, the intervals were expressed in relation to the interseptation time of c1 (T) of the respective culture. With few exceptions, the determined values were rather independent of the growth rate. On average, the fate of c2 was: start of branching at 0.7 T, doubling in length at 1.4 T, and septation at 1.7 T, meaning that septation of c1 and c2 did not occur synchronously. A second branch was formed 1.7 T after the first, i.e. at the same interval between the first (in c1) and second (in c2) septation.

The site of septation was either more or less median within the original c2‐length, or within the branch, adjacent to the branching site. The percentage of the former was higher in cultures showing delayed branching. Generally, the median position of septation prevailed. As a consequence, the branched c2 was divided into two differently sized and shaped daughter cells. On average, the branch‐receiving daughter was about 2.5 times larger than the branchless daughter.

The increase of the frequency of septation within the original c2 cells was followed for five T‐times. Rate and degree of increase was dependent on the growth rate or on the original length of c2. As a result, within all cultures the interseptal distance within the main hyphae approached a length of about 5 μm.
Some ecological and physiological studies on bacteria isolated from salt‐affected soils of Egypt
Authors: Zahran H. H. , Moharram A. M. , Mohammad H. A.
Published: February 2007

Members of Bacillaceae, Rhizobiaceae, actinomycetes and others were isolated from cultivated and non‐cultivated saline soils. The high population of bacteria and actinomycetes were almost coincided with the relatively high levels of organic matter whatever the degree of soil salinity. Bacillus stearothermophilus and B. subtilis were more frequently isolated than other Bacillus species. Most of Rhizobium isolates were salt tolerant being able to grow in media containing 3% and 6% NaCl. The abilities of different bacterial isolates to attack citrus pectin, soluble and insoluble forms of cellulose were also tested.
Microbial degradation of aquatic biomass by Trichoderma viride 992 and Aspergillus wentii 669 with reference to the physical structure
Authors: Kour J. , Maheshwari D. K. , Mehta P.
Published: February 2007

There was a considerable change in the structural parameters of both the lignocellulosic substrates. This change was confirmed by infrared (IR) spectroscopy and X‐ray diffraction data, which reveled the presence of phenolic groups in the peaks range 1310–1410 and 1200 cm−1 with large crystalline substrates. These were found to be reduced after treatment with alkali. Enzyme/s activity were found to increased after pretreatment of hydrolysed substrates. The structural modification in both the substrates were further evidenced by the results obtained after enzymatic hydrolysis of alkali‐treated substrates.
Fructose‐2,6‐bisphosphate level and β‐lactam formation in Penicillium chrysogenum
Authors: Kozma József , Bartók Gábor , Szentirmai Attila
Published: February 2007

The rate of penicillin formation in the medium containing lactose as sole carbon source markedly decreased after addition of glucose but at the same time the growth rate of fungal mycelium increased. Significant correlation was found between the formation of penicillin and the intracellular concentration of fructose‐2,6‐bisphosphate. It appears that penicillin production is influenced by the level of fructose‐2,6‐bisphosphate.
Variation in poly‐β‐hydroxybutyrate synthesis in rhizobia reflects strain differentiation and temperature regulation
Authors: Nair Suresh , Jha Prakash K. , Babu C. R.
Published: February 2007

Polyβ‐hydroxybutyrate (PHB), a carbon storage polymer, occurs widely among prokaryotes including Rhizobium. Screening of 45 strains of rhizobia, isolated from nodules of legumes inhabiting different ecological regimes, showed a wide range of variation in the PHB content. Broadly, this variation is strain‐ specific and may be used as a taxonomic character for strain differentiation. Rhizobia show minimum PHB content at optimum temperature for growth and relatively higher content at the temperature extremes implying that PHB accumulation in rhizobia is in response to stress imposed by the extremes of temperature. PHB presumably protects membrane structure of rhizobia during this stress.
Regulation of glutamate metabolism in the cyanobiont Nostoc ANTH by nitrogen sources
Authors: Singh Surendra
Published: February 2007

Growth, heterocyst differentiation, nitrogenase activity and glutamate uptake were studied in the cyanobiont Nostoc ANTH, a free‐living isolate of the liverwort Anthoceros punctatus. Nostoc ANTH grew well in N2‐medium and produced heterocyst and nitrogenase activity whereas NO‐ and NH‐grown cultures did not show heterocyst differentiation and nitrogenase activity. Also, glutamate inhibited the diazotrophic growth, heterocyst differentiation and nitrogenase activity. However, the availability of NO and NH to the glutamate‐medium resulted in the recovery of growth. NO‐ and NH‐grown cells showed reduced levels of glutamate uptake which further reduced by the supplementation of NO‐ and NH in the reaction mixture during experimentation. These results suggest that in Nostoc ANTH glutamate acts as an inhibitor of heterocyst differentiation and nitrogenase activity rather than as a nitrogen source and that availability of NO‐ and NH alleviates the glutamate toxicity by inhibiting its uptake. This glutamate toxicity may be the reason for the localization of glutamate forming enzyme, glutamate synthase (GOGAT) within vegetative cells and not within heterocysts.
Steroid metabolism with intestinal microorganisms
Authors: Groh Helmut , Schade Karin , Hörhold‐Schubert Cläre
Published: February 2007

As a result of the metabolic activities of numerous anaerobic microorganisms with sterols, bile acids and steroid hormones as substrates in connection with the enterohepatic circulation of these compounds, the intestine may be considered as an “endocrine” active site or organ.

The review summarizes transformations of steroids by anaerobic intestinal bacteria, the physiological and supposed pathophysiological meaning thereof. The aim is to recommend further investigation in this field with respect to both the elucidation of the reactions and biological responses.
Discrimination from other thermophilic Campylobacter and genometyping at the chromosomal genomic DNA level of Campylobacter lari
Authors: Matsuda Motoo
Published: February 2007

Since the respective undigested and intact chromosomal DNAs from C. coli JCM2529T, from two strains of C. coli, C. jejuni JCM2013 and from two strains of C. jejuni migrated as fragments of around 1,900 kb and the chromosomal DNAs from C. lari JCM2530T and from eleven strains of C. lari migrated as fragments of around 1,640 kb, pulsed‐field gel electrophoresis (PFGE) was clearly demonstrated to be useful for the discrimination of C. lari from two other thermophilic species of Campylobacter (C. coli and C. jejuni). PFGE revealed that SmaI generated nine distinctly different and distinguishable banding profiles from the DNA of 18 strains of C. lari, which included the type strain. Three types of banding profile, namely, A, B and C, exemplified by the nine profiles included those from five, four and three strains of C. lari, respectively. Our present attempt to discriminate and to genome‐type C. lari at the chromosomal genomic level using PFGE and SmaI may be a valuable step towards a discriminative and molecular‐epidemiologic study of C. lari.
Infection of reovirus type 3 in Mongolian gerbils (Meriones unguiculatus) – Lesions in pancreas and brain
Authors: Yukawa M. , Takeuchi T. , Mochizuki K. , Inaba Y. , Kamata H. , Onodera T.
Published: February 2007

Gerbils were inoculated with reovirus type 3 (Abney strain), and the pancreas, brain and other organs histopathologically evaluated.

Male Mongolian gerbils (Meriones unguiculatus) aged 5‐10 days (newborn, 9 animals), 4 weeks (juvenile, 5 animals), and 12 weeks (adult, 5 animals) were used. Gerbils inoculated intraperitoneally with the virus were sacrificed 3, 5, 7, or 10 days later. Tissues were observed by light and electron microscopy.

The pancreas of newborns showed inflammatory edema with infiltrates of neutrophilis and mononuclear round cells, degranulation of acinar cells and dissociation of lobules and acini with necrosis at 3 days or later after inoculation but not degeneration of pancreatic islets. Brains of newborns had necrosis of neurons and aggregation of microglial cells in the brain stem and cerebral hemisphere. Azurophilic inclusion bodies were seen in the cytoplasm of some neurons. In electron micrographs, virus particles (60‐80 nm in diameter) were observed around the nucleus of neurons in the brain stem. No changes were observed in the juvenile and adult gerbils.
Physical and functional characterization of the cloned lysl + gene of Schizosaccharomyces pombe
Authors: Ford Richard A. , Ye Zhi‐Hai , Bhattacharjee J. K.
Published: February 2007

The α‐aminoadipate pathway for the biosynthesis of lysine is present in yeast and other higher fungi. The lys2 and lys5 mutants of Saccharomyces cerevisiae as well as the lys1– and lys7 –mutants of Schizosacharomyces pombe are blocked at the α‐aminoadipate reductase step of this pathway. The cloned lys1 + gene in the plasmid pLYS1 isolated from a S. pombe genomic library complemented lys1– mutant of S. pombe. The cloned LYS2 gene in the plasmid YEp620 and the LYS5 gene in the plasmid pSC5 of S. cerevisiae exhibited heterologous complementation of lys1– and lys7– mutants, respectively, of S. pombe. The homologous lys1 + transformed cells exhibited five fold higher α‐aminoadipate reductase activity while the heterologous lys1 + and lys7 + transformed cells exhibited much less activity than the the wild type cells. The DNA insert of the plasmid pLYS1 was determined to be 16.7 kb long and the lys1 + gene has been subcloned within a 9.1 kb Clal‐Clal DNA insert of the recombinant plasmids pLYS1B and pLYS1C. The restriction pattern for 12 enzymes of the 9.1 kb DNA insert, (Apal, Aval, BamHI, Clal, EcoRI, EcoRV, HindIII, Hpal, Pstl, Pvull, Sphl, and Xbal), exbibited no obvious similarity to that of the LYS2 gene of S. cerevisiae. A 1.7 kb EcoRI‐HindIII DNA fragment of pLYS1B and pLYS1C complemented the lys1‐131 mutation in an integrative transformation. Although the lys1 + gene of S.pombe is isofunctional to the LYS2 gene of S. cerevisiae, the restriction sites, and expression of these two genes exhibited considerable divergence.
Vanadium requirement for growth on N2 or nitrate as nitrogen source in a tungsten‐resistant mutant of the cyanobacterium Nostoc muscorum
Authors: Singh H. N. , Chakravarty D. , Rao K. Srinivasa , Singh A. K.
Published: February 2007

A tungstate‐resistant mutant of Nostoc muscorum was isolated with severely defective molybdate transport activity. It did not show nitrogenase activity or nitrate reductase activity in the presence or absence of Mo, but expressed both activities in the presence of vanadyl sulphate. V‐dependent nitrate assimilation was accompanied by V‐dependent nitrate reductase mediated nitrate repression of heterocyst formation and nitrogenase in a way Mo‐nitrate reductase did in the parent.
Influence of the different amino acid substitutions in Escherichia coli thioredoxin on the growth of bacteriophages T7 and f1
Authors: Minárik Peter , Kollárová Marta , Brunovská Alena
Published: February 2007

We have constructed three mutants in the thioredoxin (trxA) gene changing its catalytic core between Cys‐32 and Cys‐35. Oligonucleotide‐directed mutagenesis was carried out to replace conservative Gly‐33 or Pro‐34 by leucine, lysine, glutamine, phenylalanine or tryptophane. The mutants were characterized using an in vivo assay based on the ability of cell (mutants in the chromosomal trxA gene) to support growth of T7 and filamentous f1 phages. The results indicate that the smaller group side‐chain in the position 33 and 34 of amino acid residues are indispensable for the growth of phages.
Co‐cultivation of tomato cell cultures with the pathogenPseudomonas syringaepv.tomato
Authors: Perner Birgit , Schmauder Hans‐Peter
Published: February 2007

The effect of a co‐cultivation with the pathogenPseudomonas syringaepv.tomato, strain 34, on plant cell cultures ofLycopersicon esculentumand its wild typeLycopersicon peruvianumwas investigated. The studied parameter were growth, vitality (TTC‐test, FDA‐test) cellular protein content, activities of polyphenol oxidase, peroxidase and PAL within the cells. Furthermore we estimated the rate of attached bacteria on the plant cell walls. The used tomato suspension cultures react in a quite different way to the pathogen.
Purification and characterization of nitrile hydratase of a mutant strain of Brevibacterium sp.
Authors: Moreau J. L. , Azza S. , Arnaud A. , Galzy P.
Published: February 2007

The nitrile hydratase from the mutant strain of Brevibacterium sp. ACV2 was purified and compared to that from the wild type R312. Its molecular weight was estimated at 80000. This enzyme is composed of 2 sub‐units with 26000 and 27500 molecular weights. The nitrile hydratase of the mutant strain is different from that of the wild type by its pHi, optimum activity pH, and its rates of hydrolysis of cyanovaleramide and cyanovaleric acid which were 30 and 15 folds greater.
Effect of phenol on the mycelial growth and fructification in some of basidiomycetous fungi
Authors: Upadhyay R. C. , Hofrichter M.
Published: February 2007

Cometabolic growth studies with phenol were undertaken to screen 32 strains of white and brown rot fungi. All the cultures studied grew well up to 4 mM of phenol on CZAPEKDOX agar except Agaricus bisporus (white button mushroom) and Pleurotus cystidiosus. Most of them could grow even up to 6 mM of phenol. Phenol induced a brown pigmentation of the culture medium. P. flabellatus and P. pulmonarius metabolized 67 and 64 mg/1 phenol in 10 days. Studies have indicated that phenol (0.1 to 1.0 mM) incorporated in malt‐extract agar has no inhibitory effect on fruitbody formation. Preliminary studies indicate that soaking of wheat straw with phenol solution up to 1600 mg/1 give better mycelial growth and fructification of P. cornucopiae, P. ostreatus Z‐15 and Calocybe indica than water soaked. Soaking of wheat straw in phenol inhibited the growth of common competitor weed fungi like Stachybotrys sp. and Coprinus sp.
Phosphorylated nutrient uptake by Treponema denticola and other potential periodontopathogens
Authors: Yotis William W. , Gopalsami Chellam , Corrigan Kevin , Hoerman Kirk , Keene Joseph J.
Published: February 2007

Nutrient uptake may contribute to the survival of certain potential periodontopathogens in the competitive environment of the gingival sulcus. This study was conducted to assess the uptake of commercially available, key radiolabelled phosphorylated compounds by Treponema denticola. There was a linear relationship in the uptake of ATP and G‐1‐P with cell concentrations of 0.1–2.5 mg of cell dry weight. This uptake reached a steady state within 15 min, and at temperatures of 25–37 °C the uptake ranged between 13–21%. At 50 °C, or above 50 °C the assay cells took up 0–1% of the assay nutrients. The maximum uptake of ATP was 47.5, 38 and 47.6 pmoles for serovars a, b and c. G‐1‐P yielded maximum uptake values of 306, 304, and 306 pmoles respectively. Significant uptake of ATP, or G‐1‐P occurred at pH 4.8 for serovars a, or c, while serovar b showed a broad pH range for the uptake of G‐1‐P. Stannous fluoride at a concentration of 0.17 mM enhanced the uptake of ATP while chlorhexidine digluconate inhibited the uptake of ATP. At concentrations usually employed (0.05–0.5 mM) the metabolic poisons 2,4‐dinitrophenol, sodium azide, sodium arsenite and the ATPase inhibitor N,N1‐dicyclohexylcarbodiimide did not alter significantly the uptake of ATP. The uptake of ATP, by Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum and T. denticola at pH 4.8 was 13.4, 1.5, 6.9, and 18–20.4%, respectively. At pH 6.5 the uptake for the microorganisms indicated above was 22, 1.3, 6.6 and 6.2%, respectively. G‐1‐P showed the same trend in its uptake by A. actinomycetemcomitans, P. gingivalis, F. nucleatum and T. denticola. This study provides for the first time specific examples of phosphorylated nutrient uptake by potential periodontopathogens, and that the uptake of phosphorylated nutrients can be suppressed by oral hygienic compounds.
Survey of mycoflora and mycotoxins in Egyptian soybean seeds
Authors: El‐Kady I. A. , Youssef M. S.
Published: February 2007

After four months in commercial storage, 100 soybean samples from different places of Egyptian Governorates were assayed for filamentous fungal growth at two incubation temperatures (28 and 45 °C). 73 species and 8 varieties belonging to 32 genera were isolated by the dilution plate method. At 28 °C, the common species were Aspergillus flavus, A. fumigatus, A. niger and A. alutaceus, followed by A. terreus, Penicillium chrysogenum, P. citrinum, Mucor hiemalis, M. racemosus, Emericella nidulans, Rhizopus stolonifer, Nectria haematococca and Scopulariopsis brevicaulis. At 45 °C, A. fumigatus was the dominant species followed by Rhizomucor pusillus, Emericella nidulans and Neosartorya fischeri. Penicillium which was one of the most abundant genus at 28 °C, absent at 45 °C. The seeds were assayed for aflatoxin, ochratoxin A, sterigmatocystin, T‐2 and zearalenone by thin layer chromatographic analysis. Aflatoxin was detected in 35% of soybean seed samples (5–35 μg/kg). The other mycotoxins were not detected.
Toxicity of legume seeds to rhizobia: Selective marker for strain identification and selection of toxin‐free seeds
Authors: Jha Prakash K. , Nair Suresh , Babu C. R.
Published: February 2007

Seeds of legume species Argyrolobium flaccidum, Desmodium elegans, D. tortuosum, Indigofera gangetica, Lespedeza stenocarpa and Sesbania sesban have been evaluated for the toxicity to rhizobia for the first time. Legume species differ in quantity and quality of released seed toxins to which the symbiotic bacteria respond differentially. Therefore, seed toxicity may be used as a selectable taxonomic marker for the strainal identification of rhizobia. Seed toxins are located in seed coat and are thermolabile to some extent. The seed genotypes, within the species, differ in toxicity and such polymorphism can be used in the selection of toxin‐free seeds. Seed surface‐disinfection procedures involving subsequent soaking and washing with water are the most useful methods for reducing the seed toxins. The seed toxins from I. gangetica inhibited the growth of its homologous strain but did not affect nodulation and symbiotic parameters. Various seed‐toxin‐producing legume species did not affect nodulation and symbiotic efficiency and effectiveness.
Cytochromes c‐dependent aerobic respiration of Paracoccus denitrificans
Authors: Kaplan Petr , Kučera Igor
Published: February 2007

Terminal parts of the respiratory chain of Paracoccus denitrificans containing cytochromes c have been investigated through the use of NNN′Nprime;‐tetramethyl‐p‐phenylenediamine (TMPD) as an electron donor. The cells have been shown to possess two major membrane bound TMPD oxidases characterized by their different sensitivities to cyanide. The more sensitive one, identified as cytochrome aa3, appears to be produced under oxygen‐rich growth conditions, whereas a less sensitive and as yet uncharacterized enzyme accompanied with only moderate amounts of cytochrome aa3 functions when oxygen becomes limiting. The soluble periplasmic cytochrome cd1 does not contribute significantly to the total oxygen consumption rate, although its maximal catalytic capacity may be high. The fact thap the activity of alternative TMPD oxidase is not proportional to cytochrome o content is discussed in relation to possible occurrence of two distinct cytochrome o‐type terminal oxidases.
Influence of the insecticide Dimethoate on some metabolic activities of five zoosporic fungi
Authors: Khallil A. M. A. , Omar S. A.
Published: February 2007

Using sesame water culture and various doses of Dimethoate, no mycelial growth appeared in cultures at rate above 5 ppm. There was no appreciable effect of the low dose of the insecticide (2.5 ppm) when incorporated into water cultures on vegetative growth, asexual and sexual sporulation of all tested fungi compared with the control. Using liquid media, respiration, mycelial dry weight as well as protease, lipase, amylase and cellulase production were varied depending upon the doses and tested fungal species.
Differential response of two species of the cyanobacterium Anabaena to ultraviolet (UV‐C) irradiation
Authors: Patnaik J. , Swain N. , Adhikary S. P.
Published: February 2007

Ultraviolet sensitivity of two different species of Anabaena, Anabaena doliolum and Anabaena sp. was studied. These two species differ in their pigment composition; A. doliolum showed predominance of phycocyanin whereas Anabaena sp. showed predominance of phycoerythrin pigments. Survival of the two species were different after exposure to different doses of UV (λmot 254 nm) irradiation; Anabaena sp. was more resistant to higher UV dose than A. doliolum. In both species the UV induced damage was partially repaired by white fluorescent light. A. doliolum showed a lower rate of photorecovery than Anabaena sp., Higher UV dose (20 min) induced production of a non‐nitrogen fixing strain of A. doliolum and a pigment mutant lacking phycoerythrin of Anabaena sp.
Metabolism and physiological behaviour of Leuconostoc mesenteroides subsp. mesenteroides growing on raffinose
Authors: Prévost H. , Phalip V. , Huang D. Q. , Diviés C.
Published: February 2007

The α‐galactosidase activities of 11 strains of Leuconostoc mesenteroides subsp. mesenteroides grown on glucose, lactose or raffinose were determined. The inductive effects of lactose and raffinose differed depending on the strain. In four of the strains, α‐galactosidase activity of cells grown on lactose was higher than that of cells grown on raffinose, while the reverse was true for one other strain. The study of two strains exhibiting a different behaviour was extended to all raffinose‐component sugars: melibiose, sucrose, glucose, galactose and fructose. The apparent fermentation yields with raffinose‐component sugars complied with heterofermentation theory, except for sucrose, where there was a 40% deficit in fermentation products. Raffinose hydrolysis enzymes (α‐galactosidase and β‐fructosidase) underwent a catabolic repression by glucose. Growth on raffinose was considerably stimulated if the inoculum was first grown on melibiose or raffinose (induction of α‐galactosidase).
Isoenzyme profiles in Azotobacteraceae
Authors: Jana Subhas Chandra
Published: February 2007

Electrophoretic comparison of isoenzymes of the members of Azotobacteraceae suggests that the genus Azotobacter consists of a heterogeneous group of bacteria. The new name Azomonotrichon macrocytogenes for Azomonas macrocytogenes is supported by the present investigation which was proposed earlier by numerical analysis study.
Iron supply of Pasteurella multocia and Pasteurella haemolotica
Authors: Reissbrodt R. , Erler W. , Winkelmann G.
Published: February 2007

Pasteurella multocida and Pasteurella haemolytica do not produce hydroxamate‐ or phenolate type siderophores. However, transport‐ and utilization systems could be detected for the well known siderophores ferrioxamine B, E, G, rhizoferrin and the intermediate 2,3‐dihydroxybenzoic acid by means of cross‐feeding tests in both Pasteurella species. Enterobactin and ferrichrome did not feed any of the Pasteurella strains tested. Additionally, α‐ketoacids and α‐hydroxyacids such as pyruvic acid, α‐hydroxyisovaleric acid and others acting as primary metabolites enabled growth of P. multocida and P. haemolytica under iron limitation.
Oomycetes and Chytridiomycetes (Mastigomycotina) from water bodies in Tübingen region (Germany)
Authors: El‐Hissy Farida T.
Published: February 2007

Twenty‐five identified and 3 unidentified species in addition to one variety belonging to ten genera of aquatic fungi were recovered from 20 surface water samples collected from different aquatic sites in Tübingen region (Baden‐Württemberg, Germany) during July‐September 1992 using sesame seeds as baiting substances. Three genera were of high occurrence; Saprolegnia (8 species), Aqualinderella (one species) and Pythium (6 species) and two genera namely Achlya (2 species) and Dictyuchus (one species) were of moderate occurrence. Allomyces (3 species + one variety) and Aphanomyces (one species) were of low occurrence whereas Olpidiopsis, Phytophthora, Pythiopsis and Thraustotheca were of rare occurrence (one species each). Saprolegnia contributed the broadest spectrum of species (8 species). The richest water samples in Saprolegnia species (7 species) and the aquatic fungal species (15 species) was number one which collected from the river Neckar while this group of fungi disappeared completely in sample number (16). It seems that the most effective factor in the occurrence and distribution of this group of fungi during this study was the water temperature.
Effect of cyanate on nitrate reduction by Rhizobium meliloti SU47
Authors: Roy Nupur , Chowdhury Aju , Roy S. , Chakrabartty P. K.
Published: February 2007

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

A L‐lysine α‐oxidase (LOD) has been purified to homogeneity in a two‐step procedure with 300‐fold enrichment and 60% recovery from the culture extract of Trichoderma viride i4. The enzyme catalyzes the reaction between L‐lysine and molecular oxygen forming 2‐oxo‐6‐aminocaproate, ammonia and hydrogen peroxide. Numerous substrates have been tested. The Km value for L‐lysine was found to be 0.026 mM. Its apparent molecular mass is 110000 Da when determined by gel filtration on Sephadex G‐200, the estimated molecular weight of the subunits being 55000 Da in the SDS‐PAGE. The enzyme is a glycoprotein and shows absorption maxima at 276, 386 and 463 nm. It was found to contain 1 mol of FAD per subunit. The coenzyme is bound non‐covalently. Its isoelectric point is at pH 4.3. The enzyme is stable at extreme pH values, at relatively high temperatures and in diluted hydrogen peroxide.

The enzyme described here differs from two other known L‐lysine oxidases previously characterized with regard to its amino acid composition and its substrate specificity.
Lipid variation at different temperatures on two species of Xenorhabdus
Authors: Maheshwari D. K. , Nishimura Y.
Published: February 2007

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

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

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

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

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

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

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

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

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