bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular cloning of a gene coding for thermostable beta‐glucanase from Bacillus macerans
Authors: Borriss Rainer , Manteuffel Renate , Hofemeister Jürgen 
Published: February 2007

AbstractThe bg/M gene DNA coding for a thermostable beta‐1.3,1.4‐glucanase of Bacillus macerans E138 was isolated by direct shot‐gun cloning into Escherichia coli using plasmid pBR322 as a vector. By deletion analysis the bg/M coding region was located within a 1.0 kb region of the cloned Bacillus DNA fragment. In E. coli, plasmid pBGLM12/2 containing the B. macerans bg/M gene gave rise to a beta‐glucanase expression 40 times higher than that of the B. macerans gene donor. The molecular weight of beta‐glucanase, isolated either from E. coli cells or from the culture filtrate of B. macerans, was in the range of 24 kD. The enzymes purified from E. coli or from the culture filtrate of B. macerans, had a halflife of about 40 min at 65 °C. This indicated an increased temperature stability of the B. macerans enzyme in comparison to other Bacillus‐beta‐glucanases.
Dihydrotentoxin: A precursor of tentoxin or its degradation product?
Authors: Liebermann B. , Ihn W. 
Published: February 2007

AbstractBesides tentoxin, dihydrotentoxin is produced by Alternaria alternata in similar quantities. Both peptides are excreted mainly into the culture medium, with a low content (20–55 μg/g) being found in the mycelium already of an early stage of fermentation. Tentoxin is not degraded during cultivation, therefore, dihydrotentoxin cannot be a decomposition product of the phytotoxin. During the isolation procedure, some tentoxin (10 to 15%) and even more dihydrotentoxin (30–40%) is lost. Incorporation of labelled dihydrotentoxin (14C, 15N) into tentoxin during fermentation allows the conclusion that the nonoxidized peptide is the precusor of tentoxin.
Microsomal oxygenases involved in ergoline alkaloid biosynthesis of various Claviceps strains
Authors: Maier Walter , Schumann Brigitte , Gröger Detlef 
Published: February 2007

AbstractThe conversions of agroclavine to elymoclavine and elymoclavine to paspalic acid/lysergic acid are catalyzed by microsomal preparations from various Claviceps strains. The enzymes designated as agroclavine 17‐monooxygenase and elymoclavine 17‐monooxygenase respectively are dependent on NADPH and molecular oxygen. NADH enhances enzyme activity observed in the presence of NADPH. Transhydrogenase activity in the presence of NADH and NADP+ which is dependent on ATP was found. Carbon monoxide, as it was shown by KIM et al. (1981, 1983) and cytochrome c inhibit hydroxylation, whereas NACN did not affect the reactions. This and other properties suggest that both clavine specific enzymes are cytochrome P‐450 dependent monooxygenases. Lysergol was not converted by elymoclavine 17‐hydroxylase. Feedback inhibition of agroclavine 17‐monooxygenase by elymoclavine was demonstrated under in vitro conditions.
Cloning and preliminary characterization of the streptothricin resistance determinants of the transposons Tn1825 and Tn1826
Authors: Tietze E. , Brevet J. , Tschäpe H. , Voigt W. 
Published: February 2007

AbstractStreptothricin resistance determinants have been cloned from the transposons Tn1825 and Tn1826 to the vector plasmid pUC8. The recombinant plasmids were characterized with respect to their physical structure. The resistance properties of their hosts were characterized with respect to the minimal inhibitory concentration of streptothricin and the activity of the streptothricin acetyltransferase. The proteins encoded by the cloned resistance determinants were analysed in a maxicell system. The results of our investigations suggest that the resistance to streptothricin is mediated by the activity of a streptothricin acetyltransferase with both, Tn1825 and Tn1826. However, the resistance determinant of Tn1825 is more complex than Tn1826 and additional functions involved in realizing the resistance phenotype must be recognized.
Genetic engineering in Yarrowia lipolytica
Authors: Gaillardin C. , Heslot H. 
Published: February 2007

AbstractThe development of a highly efficient integrative transformation system for the yeast Yarrowia lipolytica has permitted gene cloning by direct complementation. The main features of this system will be presented, as well as the results so far obtained on gene structure. Recent developments of these techniques now concern heterologeous gene expression and protein secretion and will be reviewed.
Genetic control of methanol utilization in yeasts
Authors: Sibirny A. A. , Titorenko V. I. , Gonchar M. V. , Ubiyvovk V. M. , Ksheminskaya G. P. , Vitvitskaya O. P. 
Published: February 2007

AbstractConsidered are our own data and those found in literature on the properties of yeast mutants impaired in their ability to utilize methanol as sole carbon and energy source; hypotheses about the role of alcohol oxidase and citrate synthase in biogenesis of peroxisomes are proposed. It has been proved that formaldehyde reductase participates in the control of the formaldehyde level in the cell. Properties of mutants defective in the catabolite repression and inactivation of enzymes of methanol metabolism are described. The existence of several autonomous mechanisms of the catabolite repression of alcohol oxidase has been shown. It has been found, that the induction of glyoxysomal enzymes of C2‐metabolism is repressed by methanol in the ecr1 mutant of Pichia pinus with the affected repression of alcohol oxidase by ethanol. Data are presented on the regulatory properties of the recently discovered acidification system of the medium induced by methanol. Such acidification occurs due to symport extrusion of protons and formate anions from the cells.
Construction of promoter‐probe vectors for Candida maltosa, a n‐alkane‐assimilating yeast, using the LEU2 gene of Saccharomyces cerevisiae
Authors: Takagi Masamichi , Uchino Shigeo , Sugimoto Masakazu , Kawai Shinya , Hikiji Takeshi , Yano Keiji 
Published: February 2007

AbstractFor the purpose of isolation of promoter regions which are regulated by a carbon source in the medium in an n‐alkane‐assimilating yeast, Candida maltosa, two promoter‐probe vectors were constructed. Each of them consists of the LEU2 gene of Saccharomyces cerevisiae whose 5′‐non‐coding region was trimmed with BAL31, an autonomously replicating sequence isolated from C. maltosa genome (the TRA region) which we have previously isolated, and the pBR322 sequence. One of them, pPLC2, having the TATA box, lacks the regulatory sequence (“sequence L”) of the LEU2 gene, and the other, pPLC1, lacks both the TATA box and sequence L. Using pPLC1 as a shot‐gun cloning vector in C. maltosa, many promoter regions which were active when glucose was present in the medium as a carbon source were obtained from the genome of C. maltosa. The sizes of the inserted fragments of two of them were determined. (In this paper, a promoter region refers to a promoter which includes a TATA box, plus a regulatory sequence such as an UAS (upstream activating sequence)‐like sequence).
Transformation of methylotrophic yeast Hansenula polymorpha: Cloning and expression of genes
Authors: Tikhomirova L. P. , Ikonomova R. N. , Kuznetsova E. N. , Fodor I. I. , Bystrykh L. V. , Aminova L. R. , Trotsenko Yu. A. 
Published: February 2007

AbstractWe developed a host‐vector system for transformation and gene cloning experiments using the methylotrophic yeast Hansenula polymorpha. Regeneration of protoplasts in a medium containing polyethylene glycol before plating made transformation more efficient and reproducible (2 to 3 · 104 μg DNA). The frequency of transformation was significantly lower when dominant resistance marker Cup1r was used for transformant selection. The transformation system developed was used to clone the DNA fragment which complements functionally the defect in the dihydroxyacetone kinase (DHAKAbbreviations: DHA, dihydroxyacetone; DHAK, dihydroxyacetone kinase; DHAS, dihydroxyacetone synthase; PEG, polyethylene glycol.
activity of a H. polymorpha mutant strain. The DNA insert isolated was shown to increase by up to ten times the activity of DHAK in transformants carrying recombinant plasmids. When recombinant plasmids were introduced into S. cerevisiae, the transformants obtained acquired the ability to grow on the medium with dihydroxyacetone as a sole carbon source and the activity of DHAK was observed.
Influence of cytochrome c‐deficiency on the energy conservation of whole cells of Acetobacter methanolicus sp. MB 58
Authors: Loffhagen N. , Babel W. 
Published: February 2007

AbstractThe ability of A. methanolicus sp. MB 58 and of a cytochrome c‐deficient mutant (A. methanolicus sp. MB 58105) to synthesize ATP by the oxidation of methanol, ethanol, glucose, formate and formaldehyde was investigated. It was found out that cells of the wild type were energized and that cells of the mutant were not energized by the oxidation of ethanol.The energization of cells by the oxidation of glucose, formate and formaldehyde is obviously not influenced by the cytochrome c defect. The results point to a coupling of the alcohol dehydrogenase at cytochrome c, as already postulated in a previous paper for the alcohol and the methanol dehydrogenases of A. methanolicus sp. MB 70.The dehydrogenases responsible for the oxidation of glucose and formate should be coupled to other cytochromes of the respiratory chain. Evidence for the coupling of the formaldehyde dehydrogenase could not be obtained, because it was not possible to differentiate between cytochrome‐dependent oxidation of formaldehyde and the NAD+‐dependent oxidations after fixation of formaldehyde.
Changes of protein pattern of Streptomyces griseus strains that characterize differentiation of mycelia in submerged culture
Authors: Vitális S. , Valu G. , Békési I. , Szeszák F. , Szabó G. 
Published: February 2007

AbstractS100 fractions were isolated from submerged cultures of well conidiating (No. 45H), nonconidiating (No. 52‐1) and factor C treated No. 52‐1 Streptomyces griseus strains and analyzed by one‐dimensional SDS‐PAGE. The quantity and synthesis of soluble proteins were examined on densitograms and fluorograms. The evaluation was carried out by a computer aided method. Specific radioactivities of the protein bands were also calculated.Some groups of protein bands were found to be characteristic of the two strains during development. On the other hand densitograms of the two strains could be in part superimposed showing similarities in the position and relative intensity of bands.Most of the soluble proteins were synthesized all over the life‐cycle of both strains, although characteristic individual bands appeared or disappeared during differentiation or when the two strains were compared.The protein pattern of S100 fraction from factor C treated No. 52‐1 cultures became similar although not identical, with that of strain No. 45H. Fluorograms showed closer similarities than densitograms. At 40 h there were certain peaks of specific radioactivity in the factor C treated mycelium which were missing from strain No. 45H of that age, but were expressed later in the 64 h old mycelium.Although the bands obtained by one‐dimensional SDS‐PAGE did not represent individual proteins, the results shown demonstrate that our method is suitable for the characterization of the process of biochemical differentiation. The quantitative changes of some bands detected by densiometry, fluorography and specific radioactivity may reflect important events of differentiation (Table 1).
Nitrogen regulation of avermectins biosynthesis in Streptomyces avermitilis in a chemically defined medium
Authors: Cimburková E. , Zima J. , Novák J. , Vanék Z. 
Published: February 2007

AbstractThe biosynthesis of avermectins was significantly affected by the nitrogen source used. The maximum yield of AVMs1) was achieved in a chemically defined medium with ammonium sulfate as the sole nitrogen source. Higher concentrations of ammonia inhibited the production of AVMs without the inhibition of the growth. AVMs of the group B were prevailing in the complex until 15 mM ammonium sulfate. At higher concentrations, AVMs of the group A predominated. Of various amino acids tested, lysine and asparagine were found to be the best for the biosynthesis of AVMs. The concentration of most amino acids higher than 0.2% inhibited the production, while the mycelium was still growing. The biosynthesis of AVMs was completely suppressed by 15.2 mM isoleucine, however, this inhibition was reversed by adding alanine at the beginning of cultivation.
Critical steps in degradation of chloroaromatics by rhodococci II. Whole‐cell turnover of different monochloroaromatic non‐growth substrates by Rhodococcus sp. An 117 and An 213 in the absence/presence of glucose
Authors: Janke D. , Al‐Mofarji T. , Schukat B. 
Published: February 2007

AbstractKinetic experiments were performed to examine the effect of glucose and some related compounds on the removal of different monochloroaromatic non‐growth substrates (i.e. monochloroisomers of aniline, phenol and benzoate, respectively) by resting pre‐adapted cells of either Rhodococcus sp. An 117 or Rhodococcus sp. An 213. With both strains, the use of glucose as the additional carbon substrate allowed to differentiate between “cometabolizable” monochloroaromatics (i.e. 2‐chloroaniline, 3‐chloroaniline, 3‐chlorophenol, 4‐chlorophenol whose turnover appeared to be primarily limited by the availability of reducing power and/or energy to the cells) and those which were weakly removed “under any condition” due to narrow substrate specificity of the enzymes initiating the transformation process.In a second line of investigation, the reduction of ferricyanide by resting An 117 or An 213 cells was shown to exhibit a pattern of cosubstrate‐dependence analogous to that found for turnover of the “cometabolizable” monochloroaromatics. As demonstrated with different cell preparations of strain An 117, whole‐cell ferricyanide reduction strongly interferred with the cometabolic turnover of various monochloroaromatic non‐growth substrates. The results obtained are those to be expected if the former (NAD(P)H‐dependent) type of process, in preference to the second one, would consume the reducing equivalents which become available from the metabolism of glucose. They point out the opportunity to make use of the carbon substrate‐dependent whole‐cell reduction of ferricyanide (or of other external electron acceptors) as a rapid and inexpensive assay of pre‐screening for carbon compounds which would function as energy‐replenishing cosubstrates in the (cometabolic) turnover of xenobiotic non‐growth substrates by rhodococci.
Some investigations concerning the entropy balances of microbial fermentations — primary and secondary metabolite production
Authors: Bormann E.‐J. , Grosse H. H. , Menz J. 
Published: February 2007

AbstractIn order to check the usefulness of the resulting equations of a model concerning entropy balances of microbial fermentation processes apropriate experiments were analyzed. To take into account both primary and secondary metabolism data of previously carried out fermentations of the amino acid L‐lysine and the antibiotic nourseothricin respectively were used.The obtained results indicate the agreement of the calculated values with the supposed thermodynamic relations showing the expected decrease of entropy production to a minimum as well as the zero balance of the entropy variation.The course of entropy production during the phase of product formation gave rise to discuss this phenomenon from a more general viewpoint with respect to the role of secondary metabolites as a possible way to avoid “overheating” of cells or membranes although energy substrates are available in excess.
Interconversion and glucose‐induced inactivation of glucose transport systems in Candida shehatae
Authors: Lucas Cǎndida , van Uden N. 
Published: February 2007

AbstractDuring starvation (derepression) glucose‐grown cells of Candida shehatae IGC 3607 displayed total interconversion of facilitated diffusion of glucose into a glucose‐proton symport, dependent on de novo protein synthesis (proteosynthetic interconversion). The reverse process, inactivation of the proton symport induced by glucose or 2‐deoxyglucose, was not accompanied by reemergence of the facilitated diffusion function. The inactivation process had a rapid initial and a slow second phase. The rapid inactivation depended on the external sugar concentration and was reversible while the subsequent slow inactivation was irreversible and independent of the external concentration of the signalling sugar. Interaction of the latter with a surface receptor was indicated by the range of sugar concentrations that affected rapid inactivation.
Mutants of Rhizobium meliloti defective in nodulation
Authors: Małek Wanda 
Published: February 2007

AbstractUsing nitrosoguanidine (NTG) two nodulation defective (Nod−), auxotrophic mutants of the Rhizobium meliloti strain L5.30 have been isolated. In their Sym plasmid, pRmeL5.30b, a large deletion has been demonstrated. Both mutants were adsorbed into root hairs of lucerne, but were unable to induce root hair curlings. The nodulation of lucerne was restored to both hair‐curling (Hac−) mutants by the introduction of the Sym plasmid pJB5JI of R. leguminosarum and by plasmid pEK25, carrying a 3.6 kb AvaI/EcoRI fragment of “common” nod genes of R. meliloti 41. This led to the conclusion that in these Nod− deletion mutants nod mutations were concerned with “common” nod genes.
Reduction of testosterone, androstendione and their derivatives by Aphanocladium album
Authors: Dmochowska‐Gladysz Jadwiga , Kolek Teresa , Siewiński Antoni 
Published: February 2007

AbstractA strain of Aphanocladium album reduces the C‐3 carbonyl group in testosterone or androstendione to to 3α‐allyl alcohol. In some derivatives of these steroids the same carbonyl group is reduced to allyl alcohol with stereospecificity, depending on whether chlorine at C‐4 or a 17α‐methyl group is present. On the other hand, the presence of C‐4 methyl group, a C‐19 hydroxy group, a C‐17 acetyl one, or a double bond conjugated with the 4‐en‐3‐ ketone system totally inhibits the formation of allyl alcohols at C‐3.At the samé time, the C‐17 carbonyl group in androstendione or in its derivatives is reduced to a respective 17β‐alcohol.In the derivatives with an additional 2‐exomethylene group the double bond at this group is reduced.
Adaptive growth at high temperatures of the lactose‐fermenting yeast Kluyveromyces marxianus var. marxianus
Authors: Sampaio J. P. , Spencer‐Martins I. 
Published: February 2007

AbstractThe temperature profile of growth and death rates of a strain of Kluyveromyces marxianus var. marxianus was found to be essentially dissociative, with an optimum temperature for growth at around 38 °C and sustained exponential growth up to 43–44 °C. At temperatures near the maximum temperature for growth a second growth period was observed. This did not correspond to the second branch in the ARRHENIUS plots characteristic of associative profiles, since growth was not balanced and after a while the growth rate increased to values similar to those of the first period. The biomass yield on lactose was not dependent on the growth temperature, a behaviour typical of yeast strains with dissociative temperature profiles.
Cytological effects of fungal metabolites produced by fungi isolated from Egyptian poultry feedstuffs
Authors: Abdou R. F. , Megalla S. E. , Moharram A. M. , Abdel‐Gawad K. M. , Sherif T. H. I. , Mahmood A. L. El‐Syed , Lottfy A. E. 
Published: February 2007

AbstractThe cytogenetic effects of fungal metabolites produced by 113 strains belonging to 36 fungal species and isolated from 5 substrates of commercial poultry feedstuffs were tested for their effect on the growing root meristems of Allium cepa.The fungal metabolites of Paecilomyces canescens, Aspergillus fumigatus, Syncephalastrum racemosum, Aspergillus terreus and Mucor hiemalis strongly suppressed cell division. Metabolites from other strains had less effect on cell division but permitted the appearance of several abnormalities through different mitotic stages. In general, chromosomal aberrations were more obvious with metabolites of Aspergillus species, Mucor circinelloides and Cladosporium cladosporioides.The mutagenic effects produced by these fungal metabolites reflect the risk that might take place through the consumption of these contaminated feedstuffs.
Effect of protonophore on growth of Escherichia coli
Authors: Nakano S. , Onoda T. 
Published: February 2007

AbstractWhen 20 μM of carbonyl cyanide‐m‐chlorophenyl hydrazone (CCCP) were added to a M medium containing glucose as an energy source at pH 7.6, the Escherichia coli K12 strain 3301 was able to grow, whereas on the medium containing NaCl above 200 mM, the growth was remarkably suppressed by the addition of 20 μM CCCP. Furthermore, when glucose was replaced by either glycerol or lactate as an energy source, no growth occurred in the presence of 20 μM of CCCP. When glycerol was used as a substrate, O2 consumption by whole cells was observed in the presence of 20 μM of CCCP, but not in the case of lactate. We found that 14C‐lactate uptake was completely inhibited by the addition of 20 μM of CCCP. The cells, which were incubated for 24 h on a M medium containing glucose in the presence of 20 μM of CCCP produced many more organic acids (mainly, acetate and lactate) than was the case in its absence. It appears that the influx process of external lactate when this was added as an energy source, was completely inhibited by addition of CCCP (20 μM), but the efflux process of lactate that was produced by glycolysis, was not influenced by this protonophore. On the other hand, it is suggested that on the hyposalts medium, a proton motive force (pmf) is not necessary for the growth of the strain 3301, whereas pmf is necessary for growth to occur.
Untersuchungen zum Methankreislauf in der Saale
Authors: Berger Ursula , Heyer Jürgen 
Published: February 2007

AbstractThe activities and interrelations of the processes of methanogenesis and methane oxidation were investigated in the water and sediment of the middle Saale River. The studies showed that in the impounded reaches of the river, which is heavily polluted by organic waste and inorganic compounds, sediments occur with high methane production rates (6.3–64.6 mmol/m2 · h). The methane oxidation in the surface sediment layer (20–240 μmol/1 · h) was shown to function as an effective barrier for the methane diffusion out of the sediment. The methane concentrations in the anaerobic sediment were very high (383–1696 μmol/1), but low in the water (0.33–9.3 μmol/1) in consequence of oxidation processes and water turbulence. The distribution of methane‐oxidizing bacteria was studied. High cell concentrations were found (water, 8.8 · 101 — 2.8 · 104 cells/ml; sediment, 1.3 · 106 — 1.3 · 107 cells/gram). The ecological importance of the processes of the methane cycle was evaluated by calculation of the oxygen demand (methane oxidation) and of the mineralization capacity in the river system. The anaerobic mineralization of organic matter with the methanogenesis as terminal step amounted to 59–87% of the total mineralization. The sediment and consequently the particular organic load was found to be a significant factor for estimation and control of the water quality in the river.
Enantioselectivity of the metabolism of some monoterpenic components of coniferous tree resin by Armillariella mellea (honey fungus)
Authors: Draczynska‐Lusiak Bozena , Siewinski Antoni 
Published: February 2007

AbstractTransformation of (±)α‐pinene, (±)α‐terpineol, and (±)α‐limonene by Armillariella mellea proceeds enatio‐selectively. (±)α‐Pinene oxidizes (via α‐terpineol) (to (4S)‐trans‐sobrerol faster than to (4R)‐isomer. (4R)‐Trans‐sobrerol and (4S)‐1,2,8‐p‐menthantriol are formed in excess from (±)α‐terpineol, whilst transformation of (±)‐limonene yields an excess of (4R) 8‐p‐menthene‐1,2‐diol.