bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of intrarenal oxygenation in mice by BOLD MRI on a 3.0T human whole‐body scanner
Authors: Li Lu‐Ping , Ji Lin , Lindsay Scott , Prasad Pottumarthi V.
Published: February 2007

Purpose

To extend observations on intra‐renal oxygenation with blood oxygen level‐dependent (BOLD) MRI in human and rats to mouse kidneys imaged with a human whole‐body scanner.

Materials and Methods

Renal BOLD MRI studies were performed on a 3.0T scanner using a multiple gradient‐echo (mGRE) sequence with a custom‐designed 2.0‐cm surface coil to acquire six T2*‐weighted images in mice (N = 8) at an in‐plane resolution of 156 × 156 μm2. BOLD MRI data were obtained before and after administration of furosemide (10 mg/kg intravenously [i.v.]).

Results

The mean weight of eight mice was 24.6 ± 1.0 g. The baseline renal R2* (mean ± standard error [SE]) was 28.6 ± 2.1 seconds–1 in the renal cortex (CO), 35.4 ± 2.2 in the outer medulla (OM), and 21.2 ± 2.1 seconds–1 in the inner medulla (IM). The BOLD response to furosemide (ΔR2*) was 4.1 ± 1.4 in the CO, 10.1 ± 2.1 seconds–1 in the OM, and 3.4 ± 0.8 seconds–1 in the IM in mice.

Conclusion

Intrarenal BOLD MR images with sufficiently high resolution can be obtained on a human whole‐body scanner when combined with a small receiver coil to allow studies in mice. Both baseline R2* and ΔR2* values following administration of furosemide were consistent with previous experience in humans and rats. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Differential expression of tissue inhibitor of metalloproteinases‐3 in cultured astrocytes and neurons regulates the activation of matrix metalloproteinase‐2
Authors: Liu Wenlan , Furuichi Takamitsu , Miyake Minoru , Rosenberg Gary A. , Liu Ke Jian
Published: February 2007

Matrix metalloproteinases (MMPs) degrade the extracellular matrix and are implicated in the pathogenesis of several neurological diseases. Secreted in proforms, the MMPs require activation. Tissue inhibitors of matrix metalloproteinases (TIMPs) regulate the activity of MMPs. We investigated the expression of MMP‐2 and ‐9, and the role of the TIMP‐3 in MMP‐2 activation, using cultures of cortical neurons and astrocytes. Under basal conditions, astrocytes and neurons produced low levels of pro‐MMP‐2, and ‐9. Stimulation with lipopolysaccharide (LPS) markedly increased pro‐MMP‐9 production in astrocytes, with only a slight increase in neurons. Pro‐MMP‐2 were constitutively expressed in both cell types, but with a much higher level in the astrocytes. Real‐time RT‐PCR showed that the mRNA levels of MMP‐2 and ‐9 paralleled their gelatinolytic activities in the gelatin zymograms. Interestingly, active MMP‐2 was observed only in neuronal cultures. TIMP‐2 and TIMP‐3 are constitutively expressed in astrocytes and neurons. However, astrocytes expressed much higher levels of TIMP‐3 mRNA and protein than neurons. Knockdown of TIMP‐3 with small interfering RNA (siRNA) significantly increased MMP‐2 activation in astrocytes. These results indicate that astrocytes are a more important intrinsic cellular source of MMP‐2 and ‐9 than neurons under normal and neuroinflammatory conditions. TIMP‐3 may be the key factor determining the differential activation of MMP‐2 in astrocytes and neurons. © 2007 Wiley‐Liss, Inc.
Lack of hippocalcin causes impairment in Ras/extracellular signal‐regulated kinase cascade via a Raf‐mediated activation process
Authors: Noguchi Hajime , Kobayashi Masaaki , Miwa Naofumi , Takamatsu Ken
Published: February 2007

Hippocalcin (Hpca) is a member of the neuronal calcium sensor protein family and is highly expressed in hippocampal neurons. Hpca‐deficient (Hpca–/–) mice display a defect in cAMP response element‐binding protein (CREB) activation associated with impaired spatial and associative memory. Here we examine the involvement of Hpca in the extracellular signal‐regulated kinase (ERK) cascade leading to CREB activation, because application of PD98059, a broad ERK cascade inhibitor, has resulted in similar levels of CREB activation in Hpca–/– hippocampus. N‐methyl‐D‐aspartate (NMDA)‐ and KCl‐induced phosphorylation of ERK was significantly attenuated in Hpca–/– hippocampal slices, as was ionomycin‐induced phosphorylation of ERK, whereas forskolin and 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) stimulation yielded indistinguishable levels of ERK phosphorylation in both wild‐type and Hpca–/– slices. In an in vitro reconstitution assay system, recombinant Hpca affected neither Raf‐1 protein kinase activity with recombinant MEK‐1 as a substrate nor MEK‐1 kinase activity with ERK2 as a substrate. Activation of Ras by NMDA and KCl stimulation of hippocampal slices showed no obvious changes between the two genotypes; however, phosphorylation of Raf‐1 was significantly lower in Hpca–/– slices. These results suggest that Hpca plays an important role in the activation of Raf conducted by Ras. © 2007 Wiley‐Liss, Inc.
Intermediate chain subunit as a probe for cytoplasmic dynein function: Biochemical analyses and live cell imaging in PC12 cells
Authors: Myers Kenneth R. , Lo Kevin W.‐H. , Lye R. John , Kogoy John M. , Soura Violetta , Hafezparast Majid , Pfister K. Kevin
Published: February 2007

Cytoplasmic dynein 1 is a multi‐subunit motor protein responsible for microtubule minus end‐directed transport in axons. The cytoplasmic dynein intermediate chain subunit has a scaffold‐like role in the dynein complex; it directly binds to four of the other five subunits, the heavy chain and the three light chains. The intermediate chain also binds the p150 subunit of dynactin, a protein that is essential for many dynein functions. We reexamined the generation of rat cytoplasmic dynein intermediate chain isoforms by the alternative splicing of the two genes that encode this subunit and identified an additional splicing site in intermediate chain gene 1. We reinvestigated the expression of the intermediate chain 1 isoforms in cultured cells and tissues. The Loa mouse, which is homozygote lethal, contains a missense mutation in the region of the cytoplasmic dynein heavy chain gene that binds the intermediate chain. Protein binding studies showed that all six intermediate chains were able to bind to the mutated heavy chain. GFP‐tagged intermediate chains were constructed and PC12 cell lines with stable expression of the fusion proteins were established. Live cell imaging and comparative immunocytochemical analyses show that dynein is enriched in the actin rich region of growth cones. © 2007 Wiley‐Liss, Inc.
The influence of temperature on the relations between thermal death, growth and yield in Candida utilis
Authors: Madeira‐Lopes A.
Published: February 2007

In the yeast Candida utilis an associative temperature profile was found with respect to thermal death and growth. The cardinal temperatures were the following: optimum temperature for growth, 36°C, minimum temperature of thermal death, 37.9°C; final maximum temperature for growth, 40.1°C; initial maximum temperature for growth, 40.7°C. The growth yield on glucose only decreased near the final maximum temperature for growth.
Abbau von Mischsubstraten durch Hefen III. Wachstumsparameter
Authors: Bachmann Beate , Siegel J. , Krauel H. H. , Weide H.
Published: February 2007

The growth characteristics of two Candida strains W1, W2, have been examined on the single substrates d‐glucose, d‐galactose, d‐xylose, d‐arabinose in batch culture. The importance of growth parameters μmax, KS and Y with regard to possible functions of single strains in mixed populations during degradation of mixed substrates has been discussed.
The effect of growth substrate on the levels of citric acid cycle enzymes in the facultative methylotroph Arthrobacter 2B2
Authors: Paddon C. J. , Payton M. A. , Hartley B. S.
Published: February 2007

All enzymes of the citric acid cycle were found to be present in cell‐free extracts of the facultative methylotroph Arthrobacter 2B2 except 2‐oxoglutarate dehydrogenase and pyruvate dehydrogenase. The dehydrogenase (E1) and lipoamide dehydrogenase (E2) component of 2‐oxoglutarate could be detected indicating that the complex was present, but may be very labile. No great differences in enzyme levels were detected between cells grown on trimethylamine and those on multicarbon substrates. Citrate synthase was found to be insensitive to inhibition by NADH or 2‐oxoglutarate, but some inhibition was observed with ATP.
Auswirkungen von Mutanteninduktion und Protoplastenfusion auf ausgewählte Dehydrogenase‐Muster von Pichia guilliermondii
Authors: Büttner Martina , Birnbaum D. , Böttcher F.
Published: February 2007

We investigated the enzyme patterns of two wild‐type strains, two auxotrophic mutants and some fusion hybrids of Pichia guilliermondii after the electrophoretic separation of their crude cell extracts in dependence on the cultivation on mineral salt medium with different carbon sources. The wild‐type strains showed a constitutive synthesis of one NAD‐specific and some NADP‐specific enzymes and their ability to oxidize primary alcohols with a chain length from C2 to C8. After the induction of mutants auxotroph for amino acids, nicotinic acid or adenine we found different enzyme patterns, too. Prototrophic fusion hybrids obtained via protoplast fusion of the two double auxotrophic mutants showed behaviour either characteristic for the wild‐type strains or characteristics of their parental strains and in some cases also combination of parental enzyme patterns. The behaviour of the hybrids seems to be dependent on the quantity of DNA transferred into each fusion hybrid from the parental mutant strains.

So the method of protoplast fusion allows to get qualitatively different hybrids.
A radioimmunoassay for (p)ppGpp and its application to Streptomyces hygroscopicus
Authors: Riesenberg D.
Published: February 2007

Aradioimmunoassay for (p)ppGpp was set up and applied to Streptomyces hygroscopicus. The (p)ppGpp specific antibodies obtained from rabbits immunized with ppGpp‐human serum albumin could not distinguish between guanosine‐5′‐triphosphate‐3′‐diphosphate (pppGpp) and guanosine‐5′‐diphosphate‐3′‐diphosphate (ppGpp) whereas the cross reacitivity against structurally related nucleotides was negligible. Therefore, the antibodies were used for determination of (p)ppGpp, i. e. the sum of pppGpp and ppGpp. The pretreatment of biological samples for quantification of (p)ppGpp included formic acid extraction of cell pool followed by step gradient elution on DEAE‐Sephadex A25 (Cl−) column for separation of (p)ppGpp from nucleotides with three or less phosphate groups. The very sensitive radioimmunoassay allowed determination of very low amounts: 1–50 pmoles (p)ppGpp per assay tube. The application of the RIA to S. hygroscopicus revealed a basal level in exponentially growing mycelium of about 2 pmoles (p)ppGpp per mg dry weight. The equilibrated pool size after induction of stringent response with serine hydroxamate was found to be about 30 pmoles (p)ppGpp per mg dry weight.
A stable L‐form variant of a Rhodococcus strain (B 245)
Authors: Das T. K. , Banerjee A. K.
Published: February 2007

A stable L‐form variant was isolated from a soil‐inhabiting, orange red‐pigment coryneform bacterium belonging to the genus Rhodococcus. The variant differed from the parental strain in colony and cell morphology, in growth rate and obligatory requirement of B‐vitamins and amino acids, in temperature sensitivity, in susceptibility to antibiotics affecting cell wall synthesis, and in the inability to utilize hydrocarbons as sole carbon sources for growth.
Localization of a streptothricin acetyl transferase in cells of Escherichia coli K‐12
Authors: Seltmann G. , Wolter E.‐J.
Published: February 2007

Streptothricin acetyl transferase coded for by plasmids pIE636 and pIE637 in Escherichia coli K‐12 was found to be located at the inner side of the cytoplasmic membrane.
Morphological characterization of the Serratia marcescens bacteriophage SLP
Authors: Viñas M. C. , Gargallo D. , Lorén J. G. , Guinea J.
Published: February 2007

SLP is a lambda‐like bacteriophage specific for Serratia marcescens. strains. Morphological studies have demonstrated that SLP virions present two cross‐bar structures on its tail not described in bacteriophages specific for Enterobacteriaceae. SDS‐polyacrylamide gel electrophoresis of major capsid proteins as well as electron micrographs are reported.
Invasion of wood by basidiomycetous fungi II. Obliterated differences between pathosism and saprophytism on pre‐degraded wood substrates in monoxenic culture
Authors: Gramss G.
Published: February 2007

Mycelial production and linear extension growth of 41 wood‐destroying basidiomycetous fungi (WBF) whose pathogenicity and kratovirulence levels permitted their subdivision into 7 fungal categories was determined on nonsterile and autoclaved wood dust materials from fresh, discoloured (nondecay), and decay wood samples. The resident microflora of nonsterile wood meals compels the intruding WBF mycelium to mobilize its entire competitive ability when going to colonize a contaminated substrate. This demand excludes the pathogenic WBF from utilizing the non‐sterile substrates but allows for extensive development of the fresh‐wood and successive saprophytes that afford the required kratovirulence level. On sterilized wood dust, any differences in the growth patterns of pathogenic and saprophytic WBF vanish immediately. Sterile fresh wood samples from host and nonhost trees the latter being never infected in the field allow for widely uniform mycelial production by fungal species with wide or extremely narrow host range. Some fungi display, in addition, a strong substrate preference to certain natural host tree species or their close relatives. No correlation was found between the total exoenzymatic activity reported for the fungus concerned and its mycelial production. Top values of mycelial formation were observed in fungi with lowest enzymatic activity as well as in producers of normal enzyme quantities while some brown‐rot fungi showed extremely restricted mycelial output although they are known for enzymatic activities to be highest.

Among the 41 fungal species listed, 25 prefer certain particular nondecay and decay wood samples to fresh wood meal although the general rule is a higher mycelial production on fresh wood. The addiction to pre‐degraded wood can be traced, surprisingly, throughout all fungal categories with the tendency to abate in saprophytic ones. The brown‐rot fungi are more frequently stimulated by the discoloured nondecay wood while white‐rot fungi tend to prefer decay wood samples. The partially diminutive mycelial production in certain brown‐rot fungi means no defect in vitality or wood‐decay capacity. The weekly linear extension growth figure LE7 of the fungal mycelia can reach top values throughout the 7 fungal categories. No relationship was detected between rapid mycelial growth and both kratovirulence level or pathogenic potency. Fungi most reliably transplanted to raw substrates have medium‐sized LE7 figures. It is concluded that the striking differences between pathogenic and saprophytic members of WBF they display in their competitive ability immediately vanish in the absence of substrate microorganisms. The in vitro tests neither reveal differences in a striking host substrate specificity, the preference to fresh or decay wood, mycelial dry matter production, general enzymatic particularities, and weekly mycelial growth rate.
Einfluß von Acetat auf die Bildung des Phytoeffektors Tentoxin durch Alternaria alternata (Fr.) Keissler
Authors: Hänel I. , Liebermann B. , Brückner B. , Tröger R.
Published: February 2007

The effect of the cosubstrate acetate on the formation of the phytotoxic substance tentoxin by Alternaria alternata (fr.) Keissler was investigated. Acetate was taken up and metabolized during growth. The added acetate stimulated considerably the biosynthesis of tentoxin depending on its concentration and time of introduction. There was an increased incorporation of (U‐14C)‐glucose into the toxin molecule in the presence of acetate in the medium. The results indicate an induction of the biosynthesis of tentoxin by the precursor acetate, probably mediated through the accumulation of the glycolytic intermediates pyruvate and phosphoenolpyruvate.
Induction and inactivation of phenol hydroxylase and catechol oxygenase in Candida maltosa L4 in dependence on the carbon source
Authors: Hofmann K. H. , Krüger Anne‐Kathrin
Published: February 2007

In order to investigate the regulation of phenol assimilation in the yeast Candida maltosa L4 the activities of phenol hydroxylase and catechol oxygenase were measured in crude extracts from cells grown in presence of different carbon sources.

No activities of these two enzymes have been found in cells grown on glucose, glycerol, succinate or n‐hexadecane. The phenol hydroxylase and catechol oxygenase were induced in presence of phenol. Glucose repressed the induction of both enzymes. The catechol oxygenase appeared only after complete exhaustion of glucose and in the presence of phenol. The phenol hydroxylase was already synthesized in presence of low Incentrations of glucose (<0.2% w/v).

Addition of glucose (2% w/v) to a culture of Candida maltosa L4 caused a very rapid disappearance of phenol hydroxylase activity both in the presence of phenol or after depletion of phenol. The catechol oxygenase activity decreased only slowly under these conditions.

The inactivation of phenol hydroxylase could be reversed by transferring the glucose‐treated cells into a glucose‐free and phenol‐containing medium. This reappearance of phenol hydroxylase activity could be prevented by the addition of 0.1 mM of cycloheximid, it is, therefore, dependent on de novo protein synthesis.

From these results we conclude that the glucose‐dependent catabolite inactivation of phenol hydroxylase in Candida maltosa L4 resulted in a proteolytic degradation of the enzyme.
Cyclopeptine synthetase activity in surface cultures of Penicillium cyclopium
Authors: Lerbs W. , Luckner M.
Published: February 2007

Cyclopeptine synthetase, the key enzyme of benzodiazepine alkaloid biosynthesis in Penicillium cyclopium forms cyclo‐(anthranoyl‐phenylalanyl) from anthranilic acid, L‐phenylalanine, the methyl group of L‐methionine and ATP. The following in vitro measurable partial activities of the enzyme system were followed during the development of P. cyclopium: anthranilic acid and L‐phenylalanine adenylyltransferase activities, and the ability for thioester‐binding of L‐phenylalanine to the enzyme protein. These activities became measurable at the beginning of the idiophase and reached a maximum 6 days after inoculation, i.e., the pattern of activity was similar to that of the other enzymes participating in the biosynthesis of the benzodiazepine alkaloids indicating that the activities of all enzymes of the pathway were coordinatedly expressed. Inhibitor experiments indicated that 48–55 h after inoculation a preprotein of anthranilic acid adenylyltransferase was formed, which later on became activated by a hitherto unknown mechanism.
Studies of colicin action on wall‐less stable L‐forms of Escherichia coli II. Growth inhibition of complete and wall‐less (L‐form) cells of Escherichia coli by basic colicin types
Authors: Šmarda J. , Schuhmann† Edith
Published: February 2007

The inhibitive activity of colicins of 16 types (produced by 22 colicinogenic strains) on rods and protoplast‐like stable L‐form cells of the strains Escherichia coli B, W1655 F+ and W1655 F− was compared. The results of 58 combinations tested fall into four groups (with three subgroups):

both cell forms are sensitive

both cell forms are about equally sensitive

rods are distinctly more sensitive than L‐form cells

L‐form cells are distinctly more sensitive than rods

only rods are sensitive, L‐form cells are not sensitive

only L‐form cells are sensitive rodsare not sensitive

neither cell form is sensitive.

Group la represents simple sensitivity; both cell wall and cytoplasmic membrane receptors are present and functioning. Groups 1b and 2 represent sensitivity, substantially or completely mediated by cell wall receptors. Groups 1 c and 3, represent partial or complete “pseudoresistance” or “pseudotolerance”; cell wall receptors are absent or non‐lethal, but cytoplasmic membrane ones are present and mediate the lethal effect. Group 4 represents both true resistance and true tolerance.
Studies of colicin action on wall‐less stable L‐forms of Escherichia coli III. A colicin‐tolerant mutant in a wall‐less stable L‐form
Authors: Šmarda J. , Schuhmann† Edith
Published: February 2007

The conversion of a tol III Escherichia coli mutant, tolerant to colicins E2, E3, la and K, into protoplast‐like stable L‐form makes it sensitive to colicins E2, la and K. Its original sensitivity to colicin El and tolerance to E3 are preserved in this cell form. Thus, rods of this mutant are not truly tolerant to colicins E2, la and K, but “pseudotolerant”: their wall receptors have been turned out to “nonlethal” ones by the mutation in question.
Rapid yeast DNA staining method for flow cytometry
Authors: Kuchenbecker Doris , Braun G.
Published: February 2007

The variation of the fluorescence intensity of olivomycin‐stained yeast cells as a function of the concentration of olivomycin, NaCl, and MgCl2 in the staining solution was studied.

The best results were obtained when the staining solution contained 100 μg olivomycin/ml, 40 mM MgCl2, and 1 M NaCl. A staining time of 12 min was sufficient for proper staining.
Adaptation games between microorganisms sharing a common substrate niche
Authors: Reich J. G. , Meiske W.
Published: February 2007

Microorganisms adapt their enzymic outfit to the ambient substrate supply. If several species compete for a limiting substrate, then reciprocal influence on the state of adaptation results, which has been envisaged in the paper as strategic game. The most important types of strategies, which are assessed by the governing selection rule, are called aggressive, neutral and cooperative. A cooperative strategy brings the highest advantage, but triggers the temptation to increase the gain by defection. The neutral strategy, i.e. acting as if the competitor were alone in the medium, is promising only when the selection rule favours product maximization, whereas as aggressive strategy, e.g. maximizing the difference between own and foreign profit, is most effective on growth rate maximization as selection criterion. Gruelling competition reduces the metabolic output and weakens the community as a whole against other systems.
Isolierung einer Hefezellen agglutinierenden Komponente aus Normalserum durch Zellsäulenchromatographie
Authors: Wegewitz Brigitte , Flemming Ch.
Published: February 2007

By cell column chromatography a fraction of porcine serum has been obtained that specifically reacts to the surfaces of the yeast cells of Saccharomyces cerevisiae H155. This serum fraction agglutinates only the cells of Saccharomyces cerevisiae H155 but does not those of Candida maltosa EH15 and Yarrowia lipolytica EH59, respectively.
Vorkommen von 3‐Amino‐3,6‐didesoxy‐D‐glucose in einem Lipopolysaccharid von Campylobacter coli
Authors: Seltmann G. , Beer W.
Published: February 2007

In a Campylobacter coli strain 3‐amino‐3,6‐dideoxy‐D‐glucose was detected.
Wechselwirkungen der Aldehyddehydrogenase aus Acinetobacter calcoaceticus mit Membranlipiden I. Einfluß von Detergentien, Proteinasen und Phospholipasen auf die Solubilisierung und Aktivität des Enzyms
Authors: Aurich H. , Sorger H. , Bergmann R. , Lasch J. , Koelsch R.
Published: February 2007

The NADP+‐dependent aldehyde dehydrogenase of Acinetobacter calcoaceticus was inducible by alkanes. It was located in the membranes surrounding the intracellular alkane inclusions. The enzyme could not be solubilized by changing of the pH or the ionic strength but by detergents at concentrations around the critical micelle concentration. High concentrations of detergents inactivated the enzyme; reactivation was possible by addition of natural membrane phospholipids. The enzyme in intact membranes gave lower Km values than the enzyme in the micelle form. The size of the particles of cell envelopes (including the inclusion membranes) and of micelles was controlled by measurements of the wavelength dependence of turbidity. Proteinases were unable to solubilize the enzyme; in the presence of detergent they inactivated it irreversibly. Phospholipase A2 and D inactivated the enzyme reversibly.
Metabolism of methanol by yeast and SCP production
Authors: Jwanny Etidal W. , Rashad Mona M.
Published: February 2007

The utilization of methanol by Candida lipolytica was studied with respect to the biomass, protein, lipid and other metabolites contents. Supplementation of the methanol medium with certain redox agents such as 2,6‐dichlorophenol indophenol, reduced glutathione and methyl red, showed a stimulation of both growth and protein production of C. lipolytica. At certain growth conditions the cellular yield of C. lipolytica was 0.3 g of cells/g of methanol and the protein of the biomass was 41.0%. The amino acid composition of the protein especially of the essential ones was comparable to FAO standards. Thin‐layer chromatography of the lipids indicated a dominance of total glycerides. Analyses of the acylated unsaponified fraction by gas liquid chromatography showed that campesterol was the major component.
Localization of hydrolytic enzymes in Acinetobacter calcoaceticus
Authors: Fischer B. E.
Published: February 2007

The localization of hydrolytic enzymes, phosphatase, esterase, lipase and palmitoyl‐CoA hydrolase was analysed in the cytosol, cytoplasmic membrane, periplasmic fraction, outer membrane and culture supernatant in dependence on the growth rate of the bacteria.

The unspecific phosphatase was found to be a cytosolic enzyme.

A lipase was the only extracellular enzyme detected. The results pointed to a secretion of the lipase into the culture medium via cytoplasmic and outer membrane.

The palmitoyl‐CoA hydrolase was found to be attached to the outer membrane, but activities were also detected in the periplasmic fraction.

Unspecific esterolytic activities were mainly measured in the cytosol and in the cytoplasmic membrane.
DNA replication is not restricted to specific regions in young vegetative Streptomyces mycelia
Authors: Kummer Christel , Kretschmer Sigrid , Kummer C.
Published: February 2007

In order to determine the localization of DNA‐synthesis in Streptomyces granaticolor and Streptomyces hygroscopicus, mycelia (growing either on agar or in liquid medium) were pulse‐labelled with 3H‐thymidine and prepared for autoradiography. The distribution of silver grains showed no regions of preferential incorporation of 3H‐thymidine in mycelia up 300 μm in length. Since mycelia grow by apical elongation of hyphae, the frequency of silver grains was quantitatively analysed along individual main hyphase. No significant difference of labelling was found within zones of different age up to a distance of 80 μm from the hyphal tip. Also, the very youngest part of the hyphae enclosing only the most apically situated nucleoid did not show any deviation from the average frequency of silver grains.
Comparative study of the temperature profiles of growth and death of the pathogenic yeast Cryptococcus neoformans and the non‐pathogenic Cryptococcus albidus
Authors: Madeira‐Lopes A. , Plácido M. Teresa , Cabeça‐Silva C.
Published: February 2007

The temperature profiles of two species of Cryptococcus were compared. The pathogenic Cr. neoformans had a maximum temperature for growth of 39.8 °C and the non‐pathogenic Cr. albidus, of 30.2 °C. The specific growth rates measured in the former were of an order of magnitude higher than in the latter, whereas the Arrhenius plots of the specific thermal death rates did not show a significant difference.
Expression of the Proteus mirabilis recA gene in Bacillus subtilis is directed by its own promoter
Authors: Eitner‐mönke G. , Manteuffel R.
Published: February 2007

The recA gene of Proteus mirabilis (recApm) has been cloned into the PstI site of the Bacillus promoter‐probe plasmid pPL603. When present on this plasmid, the recApm1) gene is expressed in B. subtilis under the control of its own transcriptional and translational signals. It is concluded that the high AT‐content of the DNA sequence upstream of the −35 region is of decisive importance for the usage of the recApm promoter by the B. subtilis RNA polymerase. The results are discussed in relation to the expression barriers found to exist for genes from gram‐negative bacteria in the gram‐positive B. subtilis.
Expression of the streptokinase gene from Streptococcus equisimilis in Bacillus subtilis
Authors: Klessen Christian , Malke Horst
Published: February 2007

The previously cloned and sequenced streptokinase gene (skc) from Streptococcus equisimilis H46A was inserted into plasmid vectors capable of replication in Bacillus subtilis. The skc gene was expressed by use of its own transcription and translation signals which appeared to meet the stringent requirements of B. subtilis for efficient foreign gene expression. The secreted streptokinase activity began to decline toward the end of the exponential growth phase suggesting that B. subtilis exoproteases hydrolyzed and inactivated the foreign protein.
Fractionation of ribonucleic acid transcripts synthesized during spore germination in Bacillus subtilis
Authors: Matsuda M. , Kameyama T.
Published: February 2007

Transcription was found to proceed stepwise during germination of Bacillus subtilis spores. Three distinct phases were evident with respect to pulse‐labelled RNA synthesis and the RNA species synthesized.

At the early stage of germination (Gm 1:0—15 min), RNA synthesis started in about 5 min and increased linearly when 1 min pulse‐labelling with 3H‐uridine was used. RNA molecules of relatively low molecular weight (LMW) 4S, 4.5S, 5S, LMW I, II, III, VII RNAs and so on were mainly synthesized during this stage. The relative synthesis of 16S and 23S rRNA was suppressed considerably at Gm 1. This suppression was eliminated by the mid stage of germination (Gm 2:15 to 40 min). Pulse‐labelled RNA synthesis took on a constant level for about 20 min (Gm 2). The relative amounts of LMW I, II, III and VI RNAs in an aliquot (10,000 cpm) decreased at Gm 2. Gm 2 was followed by a tremendous increase in the pulse‐labelled RNA synthesis (Gm 3 and outgrowth).

The transition from Gm 1 to Gm 2 was inhibited by chloramphenicol. LMW I, III, and VI RNAs were densely banded at Gm 2 on administration of chloramphenicol.

These results strongly suggested that transcription may be positively regulated at an early stage of germination.

Possible positive factor(s) involved in this regulation are discussed.
Oxidation of naphthalene by Saccharomyces cerevisiae and Candida utilis
Authors: Hofmann K. H.
Published: February 2007

The yeasts Saccharomyces cerevisiae 118 and Candida utilis 128 were examined for their ability to metabolize the polycyclic aromatic hydrocarbons naphthalene and anthracene. The two yeasts tested oxidized these aromatics. Metabolites were extracted and analyzed by thin layer chromatography and gas chromatography. The predominant oxidation product of naphthalene found in the culture medium was 1‐naphthol.
Frequency of acrystalliferous spore‐forming bacteria possessing flagellar antigens of Bacillus thuringiensis
Authors: Ohba M. , Aizawa K.
Published: February 2007

Flagellar (H) antigens of 189 acrystalliferous spore‐forming bacteria, referable to Bacillus cereus, isolated from soils and silkworm litters of Japan, were analyzed by using H antisera against Bacillus thuringiensis H serotypes 1–20. These isolates proved to share common H antigens at a very high frequency of 29.6% (56/189) with the known 16 H serotypes of B. thuringiensis. This indicates that, in natural environments, B. cereus possessing B. thuringiensis H antigens is distributed more widely than crystalliferous B. thuringiensis.
Monosaccharide composition of lipopolysaccharides from Campylobacter jejuni and Campylobacter coli
Authors: Beer W. , Seltmann G. , Adam Maria
Published: February 2007

The monosaccharide composition of the LPS from 5 Campylobacter jejuni strains and 7 Campylobacter coli strains has been studied. All LPS's contained KDO, heptose, glucosamine, glucose, and (with one exception) galactose. All C. jejuni and 3 C. coli LPS contained > 1% galactosamine. 3‐Amino‐3.6‐dideoxyglucose was present in all but one C. coli LPS and in only one C. jejuni LPS.
Theoretically possible yields of microbial secondary products
Authors: Bormann E. J.
Published: February 2007

Balance equations for some representatives of the main biogenetic groups of secondary metabolites were formulated which provide the known and probable reactions within the biosynthetic routes. The calculated yields Ymaxp/s with respect to the usual substrate glucose range between 0.37 and 0.9 and, obviously, they agree well with the theoretical yields of biochemically related parts of cell dry mass. The sugar derivatives correspond to carbohydrates, the β‐lactams and shikimate derivatives to proteins, and finally, the polyketides and mevalonate derivatives to lipids. From this stoichiometric point of view the secondary metabolism thus seems to possess the same biosynthetic efficiency as adequate parts of primary metabolism under the conditions of retarded growth.

The introduction of the Ymaxp/s values into an equation for substrate consumption regarding the growth, maintenance and product formation (van der Beek and Roels 1984) delivered yields which demonstrated that more than 70% of the glucose flowed into byproducts or waste metabolites, respectively.
DNA replication behaviour of individual nucleoids of two Streptomyces strains
Authors: Kummer Christel , Kretschmer Sigrid
Published: February 2007

During exponential growth mycelia of Streptomyces granaticolor and Streptomyces hygroscopicus were pulse‐labelled with 3H‐thymidine for different times. The distribution of silver grains was analyzed in the autoradiograms by using the unit cell‐concept, according to which a unit cell corresponds to the hyphal length containing one nucleoid, i. e. one genome equivalent.

All nucleoids of the mycelia were labelled, if the pulse extended for more than 50% of the doubling time. Thus, in young mycelia there were no nucleoids in which had stopped replication at all. However, the mycelia showed an increasing fraction of non‐replicating nucleoids, if the pulse was shortened. This fact indicated that nucleoids transiently lacked replication.

The fraction of non‐replicating nucleoids as determined from the latter samples allowed to calculate the replication time C of the individual nucleoids. The C period occupied about 54% of the doubling time in mycelia growing with a generation time of 96 to 415 min.

Replication of neighboured nucleoids was not synchronous.
Biotransformation of aklanonic acid by blocked mutants of anthracycline‐producing strains of Streptomyces galilaeus and Streptomyces peucetius
Authors: Schumann G. , Stengel C. , Eckardt K. , Ihn W.
Published: February 2007

Aklanonic acid is an anthracyclinone‐related pigment that was found to be an intermediate at an early stage of the biosynthesis of daunomycinone glycosides by Streptomyces griseus. We now isolated anthracycline‐negative mutants of other Streptomyces species and used them in feeding experiments with both natural and radioactive aklanonic acid. In cultures of the mutant Streptomyces galilaeus S 727 exogenous aklanonic acid was biotransformed to cinerubin A as the major product. The spectrum of the conversion products was qualitatively comparable to that of the parent strain. In cultures of mutant 21/8 derived from Streptomyces peucetius var. caesius the predominant conversion product was ϵ‐rhodomycinone. Daunomycinone glycosides were isolated in small amounts. According to results obtained with the radioactively labelled precursor aklanonic acid was completely incorporated into the molecules of the conversion products. Our findings suggest that aklanonic acid is also a natural intermediate in the biosynthesis of anthracyclines by Streptomyces galilaeus and Streptomyces peucetius. Proposed bisynthetic pathways have been constructed.
Production of deoxynivalenol and zearalenone by isolates of Fusarium graminearum Schw
Authors: Megalla S. E. , Bennett G. A. , Ellis J. J. , Shotwell O. I.
Published: February 2007

The production of deoxynivalenol (DONI) on rice, corn, wheat, and barley grains by Fusarium graminearum Schw. NRRL 5883 was investigated. Highest yields (91.9–202 ppm) were obtained on rice; yields on the other substrates were: corn (34.1–84.5 ppm), wheat (3.6–24.4 ppm), and barley (0–6.6 ppm). Fifty isolates of Fusarium from corn inoculated in the field in 1979 with a mixture of strains of F. graminearum, originally collected from corn plants infected with stalk rot, were tested for DONI production on corn. Twenty of these were also tested for zearalenone production. One isolate produced more than 200 ppm DONI, 13 produced 20–50 ppm, 17 produce 10–20 ppm, and the rest produced less than 10 ppm. The only isolate that did not produce DONI was not identified as F. graminearum. All 20 isolates tested produced zearalenone; 18 produced higher levels of zearalenone (15.4–369 ppm) than of DONI. The other 2 isolates formed essentially the same levels of zearalenone and DONI‐37 and 30 ppm, and 15 and 16 ppm, respectively.
Differential sensitivity of three cyanobacteria to the rice field herbicide Machete
Authors: Pandey K. D. , Kashyap A. K.
Published: February 2007

The effect of the rice field herbicide Machete (2‐chloro‐2′6′‐diethyl‐N‐(Butoxymethyl)acetanilide) on the growth and cell composition of Anacystis nidulans, Nostoc muscorum and Anabaena doliolum was investigated. Growth of these cyanobacteria was completely inhibited at 2.5, 5.0 and 20 μg/ml, respectively, while a slight stimulation of growth was observed at lower concentrations. Stimulation of cyanobacterial growth in the presence of low concentrations of Machete was associated with an increase in the cellular levels of phycobilins and RNA while there was little impact on the levels of chlorophyll a and DNA. Photosynthetic pigments were degraded at lethal concentrations. The toxicity of the herbicide towards N. muscorum and A. doliolum could be reversed by supplementing the growth medium with either nitrate, nitrite or ammonia. This did not apply for A. nidulans. It is suggested that Machete inhibited nitrogen fixation in the former two strains while availability of nutrients was affected in the latter strain. In either case death of the organisms was most likely due to nitrogen starvation.
Adhesion and phagocytosis of Staphylococcus aureus L‐forms
Authors: Schmitt‐Slomska J. , Michailova L. , Ivanova E. , Toshkov As.
Published: February 2007

Electron microscopical investigations on in vitro and in vivo interactions of normal Staphylococcus aureus cells with rat peritoneal macrophages showed that these bacteria were rapidly endocytosed and digested even in the absence of specific antibodies. In contrast to the parental strains oxacilin‐induced and stable variante lacking a cell wall (L‐forms) were ingested without subsequent formation of phagolysomes and digestive vacuoles. The intracytoplasmic L‐form bodies retained their characteristic ultrastructure, i. e. no visible alterations occurred.

Some morphological aspects of the L‐forms and their persistence in macrophages 7 days after intraperitoneal administration of L‐form to rats, suggest the possibility of their intracellular survival.
Spread of plasmid‐mediated nourseothricin resistance due to antibiotic use in animal husbandry
Authors: Hummel Ruth , Tschäpe H. , Witte W.
Published: February 2007

After using of the streptothricin antibiotic nourseothricin in animal husbandry for growth promotion, plasmid‐borne resistance to streptothricin could be observed in E. coli from nourseothricin fed pigs, from emploees in pig farms and from their family members. Moreover, streptothricin resistance plasmids also occurred in E. coli of man without any contact to pig farms (gut flora and even urinary tract infections). However, these individuals live in villages and towns of the territory where nourseothricin was applied to pigs. Similar streptothricin resistance plasmids belonging to different incompatibility groups were found in both E. coli from pigs and E. coli from human beings. As no coselection of resistance to drugs indispensable for therapeutic use in man was observed, the application of nourseothricin in animal husbandry has not clinical implication for human medicine yet. Nevertheless, this problem remains under further investigation.
Localization of alkaline phosphatase in Streptomyces noursei
Authors: Kretschmer S.
Published: February 2007

Alkaline phosphatase activity appeared in Streptomyces noursei strain IMET 43 716 when cultures were shifted to phosphate limitation. By using p‐nitrophenylphosphate as substrate, the activity detected at pH 9.4 was cell‐bound, as long as young mycelia were studied. Supernatant fluids of the cultures were only active, if partial mycelial lysis had taken place after incubation for several days under the influence of shear forces.

After cytochemical staining the phosphatase reaction products were microscopically visible as grains distributed rather homogeneously within the hyphal lumen. The frequency of grains was correlated to the rate of nourseothricin production. Electron microscopy of thin sections showed the phosphatase reaction products to be only present in the cytoplasm.
Die mikrobiologische Synthese von Gibberellinen
Authors: Brückner B. , Blechschmidt D.
Published: February 2007

The present review deals with some essential aspects regarding to the microbial gibberellin biosynthesis during the last 10 to 15 years.

After a brief historical outline some gibberellins resp. gibberellin‐like substances producing microorganisms (e. g. fungi, bacteria) are presented of which the ability to produce these compounds recently was published. In addition techniques to obtain mutants from the fungus Gibberella fujikuroi by means of physical and chemical methods are described. A further topic of the survey is dedicated to the biosynthetic pathway of gibberellins in the fungus Gibberella fujikuroi as well as the regulation of this biosynthetic route. In this connection especially the dependence of the biosynthesis on environmental factors (e. g. role of various carbon and nitrogen sources in the medium and their relation to each other) are demonstrated.

Also a possible role of the gibberellins for the producing fungus itself is discussed.

Finally, new fields of application for gibberellic acid and the gibberellins GA4 and GA7 (e. g. animal production, pharmaceutical industry) are presented.
Ultracytochemical localization of aldehyde dehydrogenase in Acinetobacter calcoaceticus
Authors: Sorger H. , Aurich H. , Fricke B. , Vořišek J.
Published: February 2007

A membrane‐bound aldehyde dehydrogenase is induced in Acinetobacter calcoaceticus grown on aliphatic hydrocarbons as sole carbon source. This enzyme is NADP‐dependent and is able to oxidize medium‐ and long‐chain aliphatic aldehydes to their corresponding fatty acids. Electron micrographs of sectioned alkane‐adapted bacteria showed hydrocarbon inclusions in the cytoplasmic matrix. The cytochemical phenazine methosulphate‐tetranitro tetrazolium blue capture reaction allowed to localize the activity of the aldehyde dehydrogenase near the surface of these inclusions. At the same location we also found a NADPH tetrazolium‐reducing activity.
Zum Vorkommen von Hop‐22(29)‐en in Acetobacter methanolicus IMET B 346
Authors: Vier B. , Voigt B.
Published: February 2007

A hydrocarbon was isolated from a lipid extract of Acetobacter methanolicus IMET B 346 (carbon source: methanol) and identified as hop‐22(29)‐ene.
Construction of bacterial strains with novel degradative capabilities for chloroaromatics
Authors: Reineke W.
Published: February 2007

Biodegradation of most naturally occurring compounds is relatively fast, since microorganisms have evolved appropriate enzyme systems. However, biodegradation is less likely in the case of man‐made compounds like haloaromatics, which have structural features rarely or never encountered in natural products.

One strategy to develop new metabolic activities for novel compounds by strains of microorganisms is by the alteration of their existing genetic information. The present paper summarizes results of studies where the degradation capabilities of bacteria were expanded by genetic material from external sources either by natural exchange or by cloning procedures.
Codon usage in streptococci
Authors: Malke Horst
Published: February 2007

Codon usage was analysed for 14 streptococcal genes or significant open reading frames and found to be different from that in Escherichia coli and Bacillus subtilis. In particular, the preferred use of WWT codons over WWC was inconsistent with the rule of optimal codon‐anticodon interaction energy. On the other hand, for SSTC codons, adherence to this rule was better in streptococci than in E. coli. A preliminary codon bias table generated with the Pustell computer program for the analysed streptococcal genes may prove useful for the detection of protein coding regions in newly sequenced DN As from both streptococci and staphylococci.
Crown rot fungi of Nigerian bananas cv. Robusta and the effects of benomyl on their exo‐enzymes
Authors: Ogundero V. W.
Published: February 2007

Eight species of fungi were consistently obtained from crown rots of Nigerian bananas cv. Robusta. The predominant species were Botryodiplodia theobromae PAT. and Colletotrichum musae (BERK. & CURT) VON ARX. Others include: Ceratocystis paradoxa (DADE) C. MOREAU, Fusarium solani (MART.) SACC., Fusarium roseum SAYD. & HANS, Fusarium moliniformae SHELDON, Fusarium oxysporum SCHLECHT and Verticillum theobromae (TURC.) MASON & HUGHES. Growth‐temperature relations showed that B. theobromae and C. musae grew best at 30 °C within the 8‐day incubation period. Both fungal species produced extracellularly, amylases, pectin (methyl) esterase and CM‐cellulases. The synthesis of these enzymes was completely inhibited by the presence of the fungicide benomyl at concentrations of 200 ppm and above in the growth medium. At lower concentrations (50–150 ppm), pectin esterase and CM‐cellulase production was also suppressed while amylases were produced in measurable amounts.
The survival of propagules of Macrophomina phaseoli and Diplodia maydis in Nigerian soils
Authors: Durojaiye J. A. , Ikotun T. , Fajemisin J. M.
Published: February 2007

Weekly isolations from sterile and unsterile soils artificially inoculated with Macrophomina phaseoli and Diplodia maydis showed a decline in numbers of the propagules of these pathogens. Sclerotia of M. phaseoli and spores of D. maydis could not be recovered either on dilution plate or on soil plates after four weeks of inoculation of unsterile soil and after fifteen weeks for D. maydis and twenty‐five weeks for M. phaseoli in sterile soil. In unsterile soil, sclerotia‐like structures were observed with the aid of a light microscope up to the tenth week after soil inoculation by the flotation technique but their viability could not be determined due to active parasitization by Penicillium sp. and Trichoderma sp. The high number of these hyperparasites/g of soil may be responsible for the non‐detection of these pathogens in soils of some maize‐growing states in Nigeria, as well as a reduction in their longevity in soil. It thus seems, from this study, that the host tissue is the site of survival of propagules of these pathogens from one season to another.