bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of nourseothricin (streptothricin) on the outer membrane of sensitive and resistant Escherichia coli strains
Authors: Seltmann Guntram , Wolter Ernst‐Jürgen
Published: February 2007

Nourseothricin (streptothricin) causes disturbances (perforations) in the outer membrane of sensitive E. coli strains allowing lysozyme and deoxycholate, but not the periplasmic alkaline phosphatase to penetrate. EDTA slightly increases, but Mg++ ions slightly decrease this effect. The cell walls of three from four nourseothricin‐resistant strains do not become permeable under these conditions, but remain sensitive against TRIS/EDTA. Nourseothricin is supposed to pass the outer membrane of sensitive bacteria via some kind of “self‐promoting” pathway. This way can (but need not) be blocked in resistant strains.
Fatty acids and production of tylosin‐like compounds in Streptomyces fradiae
Authors: Vančura Aleš , Řezanka Tomáš , Maršálek Jaroslav , Křišťan Vladimir , Basařová Gabriela
Published: February 2007

The composition of fatty acids and the spectrum of macrolide antibiotics produced in 7 mutant strains of Streptomyces fradiae, a tylosin producer, were investigated. The strains under investigation differed in the production level and representation of individual tylosin‐like compounds. The composition of fatty acids in the mycelium did not depend on the total production. However, the strains producing relomycin in addition to tylosin produced a significantly higher fraction of fatty acids with a higher melting point, and, on the contrary, the strains producing only tylosin or tylosin and desmycosin synthesized a significantly lower proportion of these acids. The results obtained indicate that in addition to the activity and substrate specifity of secondary metabolism enzymes, the composition of the tylosin‐like compounds produced can be influenced by the cell membrane and its function.
Nachweis einer NAD abhängigen Gluconat‐6‐phosphat‐Dehydrogenase in Pseudomonas syringae pv. phaseolicola
Authors: Sauerstein J. , Jacob J. , Reuter G.
Published: February 2007

Crude extracts from cells of Pseudomanas syringae pv. Phaseolicola, a fluorescent pseudomonad, when grown on glucose contain a NAD‐linked 6‐phosphogluconate dehydrogenase. The reaction of the enzyme, which produces 14CO2 from 1‐14‐C‐6‐phosphogluconate, is not inhibited by NaF, a potent inhibitor of the ENTER‐DOUDOROFF (ED) pathway enzyme 6‐phosphogluconate dehydratase. In the presence of phosphate or arsenate ions the NAD‐linked glyceraldehyde‐3‐phosphate dehydrogenase reacts with glyceraldehyde‐3‐phosphate which, in the ED pathway, is produced from 6‐phosphogluconate and overlaps the 6‐phosphogluconate dehydrogenase reaction. Only a small proportion of glucose is metabolized via the 6‐phosphogluconate dehydrogenase/oxidative pentose phosphate pathway.
Oxidation of selected p‐menthane derivatives by means of Armilariella mellea (honey fungus), a parasite of woodlands
Authors: Draczyńska‐Lusiak B.
Published: February 2007

Armillariella mellea strains were found to oxidize ‐terpineol (1), limionene (2) and 1‐p‐menthene (3). The ring double bonds were converted into respective 1,2‐trans‐diols. Furthermore, several products of allylic hydroxylation were obtained. Trans‐sobrerol (6) and 7‐hydroxy‐α‐terpineol (8) were formed from 1 and 6‐hydroxy‐carveol from 2. Phelandrene (4) and p‐cymene (5) were found resistant to the enzymatic system of Armillariella mellea.
Nucleoid segregation pattern during branching in Streptomyces granaticolor mycelia
Authors: Kretschmer Sigrid
Published: February 2007

A survey of GIEMSA‐stained S. granaticolor mycelia grown in liquid medium revealed that branches developed only in subapical older regions of main hyphae for which large nucleoids were characteristic. The branches themselves contained only small nucleoids, as did the apical (about 30 μm long) region of the main hyphae. From the distribution pattern of the nucleoids at nascent branching areas it was concluded that during branch outgrowth one large nucleoid segregation into two small ones, both of which in most cases entered the branch.

In order to determine in vivo the number of genome equivalents provided from main hyphae for a single branch, the kinetics of outgrowth of branches was measured and compared to that of germ tubes. The analysis of series of micrographs revealed that at the beginning of outgrowth, a branch received two genome equivalents from the main hypha while a germ tube got only one (from the spore). The subsequently expressed exponential elongation of branches as well as germ tubes ruled out that further nucleoids were supplied thereafter.
Utilization of various concentrations of free cystine by the fungus Microsporum gypseum
Authors: Kunert J.
Published: February 2007

The dermatophyte Microsporum gypseum was cultivated on two liquid media enriched with 50 to 1000 μg/ml free L‐cystine. The presence of cystine in concentrations above 250 μg/ml (gelatin medium) or 500 μg/ml (glucose‐glutamate medium) inhibited the growth. In all variants, however, cystine was utilized from the very beginning of growth and exhausted completely until stationary phase. The rate of cystine metabolization grew with its concentration to 500 μg/ml but decreased again with 1000 μg/ml. The excess sulfur was oxidized and excreted back into the medium mainly as inorganic sulfate. Moreover, sulfite was also produced which immediately reacted with the residual cystine in the medium giving rise to S‐sulfocysteine. Sulfite excretion was higher in the initial phases of growth and on the medium with poorer growth (gelatin medium). The sulfate‐to‐sulfite ratio was different on the two media used but was little influenced by cystine concentration. The excretion of strongly acidic compounds (sulfate, sulfite, and S‐sulfocysteine) reduced the usual alkalinization of the medium in the course of growth.
Phenol hydroxylase from Rhodococcus sp. P 1
Authors: Straube Gunhild
Published: February 2007

The enzyme phenol hydroxylase (EC 1.14. 13.7) was determined and characterized in crude extracts of Rhodococcus sp. P 1. This enzyme catalyzed the first step of phenol degradation. It was inducible, had a pH optimum of 7.9 and ad temperature optimum at 20 °C and catalyzed also the hydroxylation of some other phenolic compounds.
Effect of cultivation temperature and light intensity on fatty acid production in the red alga Prophyridium cruentum
Authors: Řezanka T. , Doucha J. , Mareš P. , Podojil M.
Published: February 2007

The spectrum of fatty acids was studied in a unicellular red alga Prophyridium cruentum, strain 1380‐1a, grown in a photostate at 21, 24 and 28 °C and irradianee 30 and 60 W · m−2. Basic growth characteristics were determined for the strain under these conditions.

The proportion of unsaturated fatty acids (18:2, 20:4, 20:5) increaserd with decreasing cultivaration temperature, their relative proportion changing depending on irradition intensity; the proportion of 18:2 and 20:4 acids was higher at a substraturation irradiance (20 W · m−2) while at saturation irradiance (60 W · m−2) the proportion of the 20:5 acid was substantially increased. The production os atured acids (16:0) declined with decreasing temperature.
Production of interferon by peritoneal cells of several inbred mouse strains
Authors: Błach‐Olszewska Zofia
Published: February 2007

The ability of peritoneal cells isolated from different strains of inbred mice to spontaneous interferon production was examined. AKR, C3H, and CBA mice which are known to develop spontaneous diseases such as lymphatic leukemia, mammary tumors or hepatomas in high percentage did not produce physiological interferon. On the other hand, peritoneal cells of BALB/c, 129, DBA/2 mice showed IFN production. In the early phase of their ontogenic development NZB mice were found to produce high titers of the interferon.

Differences were found in the contents of a natural IFN‐synthesis‐inhibitor between C3H and NZB mice and are considered as one of the reasons of differentiated physiological interferon synthesis. The disturbance in the regulation of the physiological IFNs synthesis in the development of neoplastic and autoimmune diseases is discussed.
Einsatz einer Mischkultur in Acetat‐Fermentationen
Authors: Mallach Cornelia , Noetzel Rainer , Meyer Manfred
Published: February 2007

Bacterial cultures were selected from the native flora of liquid manure in order to metabolize liquid manure substances. The mixed culture used in the growth experiments is characterized by low growth rates when maximum degradation of acetate occurs. The biomass concentration reached 2.2 g/l.
Mixed cultures fermentation for bioconversion of whole bagasse into microbial protein
Authors: Nigam Poonam , Pandey Ashok , Prabhu K. A.
Published: February 2007

Two basidiomycetes cultures, BH1 and BW1, isolated from the biomanure sample of a bio‐gas plant belonging to Polyporus sp., were used in combination with celluolytic cultures viz. Trichoderma sp. and Cellulomonas strain R2 for microbial protein production from whole bagasse. The biomass yields obtained were much higher in mixed cultures fermentation than in corresponding controls. Combination of BH1/BW1 with Cellulomonas proved to be the better in comparison with Trichoderma. Simultaneous inoculation of the bacteria along with BH1 culture resulted in higher protein production.
Electrofusion ofPenicilliumprotoplasts after dielectrophoresis
Authors: Groth I. , Jacob H.‐E. , Künkel W. , Berg H.
Published: February 2007

The protoplast fusion of auxotrophicPenicilliummutats after dielectrophoretic cell contact and rectangular field pulses (4,2 kV/cm, 25 μs) was microscopically observed in a microchamber consisting of two vapour‐plated chromium electrodes on a microslide (gap between the electrodes of about 150 μm). The conditions for protoplasting ofPenicilliumand for electrofusion are described. Isolation of viable fusion products was realized.
In vitro and in vivo production of pectolytic enzymes by some phytopathogenic fungi
Authors: Ikotun T. , Balogun O.
Published: February 2007

Five fungal plant pathogens were investigated for their in vitro and in vivo ability to produce pectolytic enzymes. Only Fusarium solani did not produce any appreciable amount of enzymes in vivo and in vitro. Alternaria solani, Collectotrichum truncatum, Colletotrichum capsici and Curvularia pallescens produced pectolytic enzymes in vitro which were detected after ten‐fold concentration of the cultures by ammonium sulphate precipitation. These same four fungi produced pectolytic enzymes in vivo which were detected after twenty‐fold concentration of blended infected host tissue. The pH values of peak enzyme activity of 3.0 and 5.0 indicate that the enzymes produced were polygalacturanaes. The monogalacturonide end‐product of sodium polypectate and cell wall degradation indicate that exopolygalacturonases were produced by the pathogens. The low concentration of these enzymes in infected host plant tissues and the slow pectate‐splitting action of the exopolygalacturonases produced may account for the slow development and the dry necrotic nature of the disease these fungi cause.
Saprophytic fungi isolated from animal and bird pens in Egypt
Authors: Moharram A. M. , Bagy M. M. K. , Abdel‐Mallek A. Y.
Published: February 2007

Forty four samples collected from animal and bird pens were screened for their content of saprophytic fungi by using the dilution plate method. 76 species in addition to one variety of Aspergillus flavus belonging to 33 genera were recovered on three types of media: 20 genera and 49 species on LITTMAN‐oxgall agar, 19 genera and 41 species on cellulose‐ and 19 genera and 43 species on glucose‐Czapek's agar. The most frequent genera were Aspergillus (21 species), Scopulariopsis (4 species) and Penicillium (10 species). Among the isolated fungi A. fumigatus, A. flavus, A. terreus, A. niger, A. sydowi, A. nidulans, S. brevicaulis, S. brumptii, P. chrysogenum and P. funiculosum were the most common species.
Studies on bacterial synergism in mice infected with Bacteroides intermedius and Fusobacterium necrophorum
Authors: Price Stuart B. , McCallum Roderick E.
Published: February 2007

The study was undertaken to characterize the kinetics of possible bacterial synergy using a mouse model of mixed intraabdominal infection with Bacteroides intermedius and Fusobacterium necrophorum. Female CD‐1 mice were injected intraperitoneally with B. intermedius, F. necrophorum or mixtures of both organisms. Generalized septic peritonitis developed within 24 hr, with abscess formation occurring after one to two wk in survivors with the mixed infection. Involvement of the reticuloendothelial system was evidenced by dose‐dependent hepatosplenomegaly, which appeared during the first wk postinfection and progressed throughout the course of the exepriment. Indirect immunofluorescence confirmed the presence of both species of bacteria in frozen sections of liver tissue. The median lethal dose (LD50) was 2.11 × 109 for the mixture, 3.03 × 109 for B. intermedius alone, and 1.07 × 109 for F. necrophorum alone. The median abscess‐producing dose (AD50), the dose required to produce abscessess in fifty percent of the surviving mice at two wk, was approx. 1/100 of the LD50 dose. The AD50 for intrahepatic abscesses was 2.8 × 108 for the mixture, whereas the AD50 for intraabdominal abscesses occurring in any site was 5.14 × 107. Both Bacteroides and Fusobacterium persisted in tissue for at least 22 wk following mixed infection. The persistence of the Bacteroides in tissue represents a synergistic result of mixed infection with Fusobacterium and contributed to the chronicity of intraabdominal abscess formation. Bacteroides, injected alone, did not produce abscesses at any of the doses tested. However, when passaged (isolated from mixed infection hepatic abscesses) B. intermedius was used, the bacteria did induce abscesses.
Effect of oxygen concentration on denitrification in freshwater sediment
Authors: Trevors J. T. , Starodub M. E.
Published: February 2007

The effect of different O2concentrations on denitrification in freshwater sediment was studied using the acetylene blockage technique. Denitrification occurred over a wide range of O2concentrations ranging from 10.1 to 0.33 μmol ml−1in nitrate amended sediment. However, denitrifying activity was not observed in sediment incubated under similar conditions when NO3‐was absent. These observations suggested that an anoxic environment or low O2concentrations were not required for denitrification to occur, if NO3‐ was initially present in the sediment. Denitrification gradually decreased as the dissolved O2concentration in sediment increased to 0.25 μmol ml−1. However, between 0.25 and 0.35 μmol ml−1dissolved O2, denitrifying activity was higher than at the lower dissolved O2concentration (0.25 μmol ml−1).
Effect of NaCl on the accumulation of glycerol by three Aspergillus species
Authors: Zidan M. A. , Abdel‐Mallek A. Y.
Published: February 2007

The accumulation of glycerol was investigated in three Aspergillus species, A. niger, A. ochraceus and A. tamarii after being grown in media containing different NaCl concentrations. Intra‐extracellular as well as total glycerol were markedly accumulated by the three organisms in response to increased salinity. However, at salinity levels of 10–14% NaCl, extracellular glycerol was somewhat lowered. In addition, it was found that the maximum accumulation of glycerol in A. niger and A. tamarii was reached within the first 10 hours after salinization. However, after desalinization, the extracellular glycerol was continuously increased within the first 6 hours at the expense of intracellular glycerol.
Isolation and characterization of the extracellular lipase of Acinetobacter calcoaceticus 69 V
Authors: Fischer B. E. , Kleber H.‐P.
Published: February 2007

The extracellular lipase of Acinetobacter calcoaceticus 69 V was purified by hydrophobic interaction chromatography to homogeneity as suggested by gel electropheretic analysis.

The lipase existed as a high molecular complex of about 300 kDa, with a subunit molecular weight of 30.5 kDa being obtained by SDS‐PAGE. The hydrodynamic molecular radious obtained by gel electrophoresis was 3.27 nm.

The lipase had an isoelectric point of 5.5 and was stimulated by additions of deoxycholate. The activation energy for the hydrolysis of p‐nitrophenyl palmitate was 39.9 kJ mol−1. Tri‐, di‐ and monoacylglycerols were hydrolyzed. Hg2+ and p‐hydroxymercuribenzoate inhibited the enzyme activity at very low concentrations. One sulfhydryl group was found per molecule of lipase.
Influence of Gramoxone and paraquat on growth and respiration of Azotobacter vinelandii
Authors: Gadkari Dilip
Published: February 2007

The influence of the herbicide Gramoxone and its active ingredient paraquat on growth and respiratory activity of Azotobacter vinelandii was studied. The experiments were performed in nitrogen‐free medium and in medium with combined nitrogen. Addition of Gramoxone (50 ppm) or paraquat (15 ppm) to the cultures during lag phase caused a total inhibition of growth. However, even after 24 h of incubation in the presence of herbicides the number of viable counts did not decrease. When herbicides were added to exponentially growing cultures, the growth response of the cultures was different. After addition of herbicides only a transient short inhibition period was noted and the length of the inhibition period was dependent on the time of herbicide addition. Neither Gramoxone (50 ppm) nor paraquat (15 ppm) enhanced catalase production. The respiratory activity of paraquat‐treated cells in the presence of 1 mM KCN was distinctly reduced (75%), while that of untreated cells did not change.
Development of a plasmid‐cloning system for Streptomyces viridochromogenes Tü494
Authors: Strauch E. , Wohlleben W. , Pühler A.
Published: February 2007

A plasmid‐cloning system was developed for Streptomyces viridochromogenes Tü494, a producer of the tripeptide antibiotic phosphinothricyl‐alanyl‐alanine (PTT). Parameters affecting protoplast formation and transformability of S. viridochromogenes were investigated in detail. A procedure giving rise to transformation efficiencies of 104–105 transformants per μg DNA was worked out. Several Streptomyces plasmid vectors such as pIJ350, pIJ61, pEB2, pGM4 and pSW2 were tested in S. viridochromogenes. Some of these vectors (pGM4, pEB2) showed a high copy number, whereas the copy number of others (pIJ350, pIJ61 and pSW2) was markedly lower. Under non‐selective conditions some of the vectors (pIJ350, pEB2) were not stably maintained, in contrast to the vectors pGM4 and pSW2 which did not require any selection pressure for stable meintanance. Therefore, the plasmid vectors pGM4 and pSW2 derived from endogenous replicons of Streptomyces ghanaensis strains represent appropriate plasmid vehicles for cloning experiments in S. viridochromogenes.
Effect of growth temperature on the externalization and localization of α‐amylase in Bacillus stearothermophilus
Authors: Bezbaruah R. L. , Pillai K. R. , Gogoi B. K. , Singh H. D. , Baruah J. N.
Published: February 2007

The synthesis and localization of α‐amylase were studied in Bacillus stearothermophilus AN002 at 40, 45, 50 and 55 °C and also during early exponential, late exponential and stationary phases of growth. The extracellular α‐amylase synthesis was highes at 50 °C and at stationary growth phase. Accumulation of intracellular α‐amylase was observed in cells grown at 40 °C and was distributed in all the cell fractions. At 50 and 55 °C the cell did not have α‐amylase in the protoplasm or protoplamic membrane. The synthesis and externalization of extracellular enzyme are two processes and the externalization is controlled by growth temperature and cell age.
The ability of Aphanocladium album and Rhodotorula mucilaginosa to transform some compounds of juvenoid type
Authors: Dmochowska‐Gładysz J. , Kołek T. , Siewiński A. , Derdziński K. , Zabza A. , Galera E. , Walkowiak U.
Published: February 2007

The strains of Aphanocladium album (isolated from insects Tenebrio molitor) and Rhodotorula mucilaginosa reduce α,β‐unsaturated ketone groupings in (±)5‐(2′,2′,3′‐trimethy1‐3′‐cyclopenten‐1′‐y1)‐3‐penten‐2‐one, pseudoionone or in its (±) γ,δ‐dihydro‐derivative to respective saturated alcohols.

The strains reduce the same carbony1 group to both alcohols in two enantiomeric 3,4‐dihydroderivatives of the first substrate as well as in () hexahydro‐analogue of pseudoionone. For all these substrates, the transformations were found to be enantiospecific.
Selektion und biotechnische Herstellung von Kulturlösungen mikrobieller Antagonisten zur Unterdrückung phytopathogener Bodenpilze
Authors: Huber Johann , Bochow Helmut , Junge Helmut
Published: February 2007

Two strains of bacteria,Bacillus subtilisT 99 andStreptomycessp. G43, antagonistic to phytopathogenic soil fungi, were isolated from natural substrates.In vitrotests indicated activities against differentFusariumspecies including formae speciales ofFusarium oxysporum, Stromatinia gladioli, Botrytis cinerea, Thanatephorus cucumeris, and other fungi. For both of the antagonists, biotechnical procedures were developed yielding culture broth for large‐scale application. After dilution of these media antagonists were tested successfullyin vivoby soil drenching treatments in a greenhouse carnation production facility. The application forms of the fermentation media developed were capable of suppressing wilt disease ofDianthus.
Temperature and aflatoxin production by Aspergillus flavus and A. parasiticus strains from Nigerian groundnuts
Authors: Ogundero Vincent W.
Published: February 2007

The ability of four strains of Aspergillus parasiticus (IMI 301 001) and two strains of Aspergillus flavus (IMI 300 998) to produce aflatoxins on Nigerian groundnuts under varying conditions of temperature was studied. While all the A. parasiticus strains produced the four major aflatoxins (B1, B2, G1, G2), only aflatoxin B1, and B2 were produced by the A. flavus strains used. The optimum temperature for aflatoxin production by both the fungal species was 30 °C with no toxin production at 10 °C.
Partial purification and characterization of anhydrotetracycline oxygenase of Streptomyces aureofaciens
Authors: Vančurová Ivana , Flieger Miroslav , Volc Jindřich , Beneš Milan J. , Novotná Jana , Neužil Jiří , Běhal Vladislav
Published: February 2007

Anhydrotetracycline oxygenase was purified both by affinity chromatography and by hydrophobic interaction chromatography. Molecular weight of anhydrotetracycline oxygenase was determined to be 115,000 by Sephadex G‐200 gel filtration. Using preparative isoelectric focusing the isoelectric point of the enzyme was estimated to be 5.3. The enzyme showed a sensitivity to thiol‐specific inhibitors. During the hydrophobic interaction purification step, the activity dropped considerably. Reactivation occurred when a heat treated crude extract was added to the reaction mixture.
Ultrastructural studies on the cyanobacteriumNodularia spumigenaand its epiphytic bacteria of the genusSeliberia
Authors: Gumpert J. , Šmarda J. , Hübel M. , Hübel H.
Published: February 2007

A 400–900 nm thick slime sheath showing 2–3 layers of different thickness and fibril orientation as well as large amounts of densely packed gas vesicles are characteristic for vegetative cells ofNodularia spumigena, a cyanobacterium, forming extended water blooms in the Baltic Sea. Comparative SEM and TEM investigations revealed typical screw‐like shaped epiphytic bacterial cells anchored in the slime sheath ofNodulariatrichomes. Their unique helically sculptured surface is characteristic for the genusSeliberia.Two types ofSeliberiacells can be distinguished, regarding cell morphology, formation of apical spherical bodies and their occurrence on host organisms. The main ultrastructural peculiarities concern a helically sculptured membraneous cell wall, a 100–250 nm large, heavily stained inclusion granulum in the cytoplasm of the anchored polar region, and a pad‐structure with associated hold‐fast material surrounding the polar cap, which is attached to the slime sheath. A permanent subcultivation of pure cultures ofSeliberiaepiphytes could not be obtained. In samples from natural water blooms,Nodulariacells were found to contain single or numerous gram‐negative rod‐shaped bacteria, and to show a more or less advanced destructio of the intracellular organization.
Leucine aminopeptidase in intracytoplasmic membranes of Acinetobacter calcoaceticus
Authors: Ludewig M. , Fricke B. , Aurich H.
Published: February 2007

Cells of Acinetobacter calcoaceticus strain 69‐V contain an aminopeptidase that cleaves L‐leucine amide, leucylglycine or lecine hydrazide with high efficiency. Leucine 4‐nitroanilide and alanine hydrazide are hydrolyzed to less than 0.1% and 1%, resp. of leucine amide.

Grown on acetate‐NH+4 medium the activity of the enzyme in the cytoplasm is increased 5‐fold compared with cells grown on a casamino acid medium or on yeast extract. In these cases the specific activity of the unpurified enzyme is about 5 nkat/mg for the cytoplasmic and membrane‐bound enzyme species as well.

Up to 30% of the aminopeptidase activity were found mainly in intracytoplasmic membranes, less in cytoplasmic membranes and only traces in outer membranes, presumably as contaminations. It is solubilized by detergents but not by high salt concentrations. An addition of antipain or Z‐Ala2‐Phe‐CH3 before cell rupture did not change the distribution of the enzyme. A mixture of EDTA and 1.10‐phenanthroline diminished the membrane‐bound enzyme from 11.4% to 4.3% and leupeptin or E‐64 increased it to 20%. The enzyme is regarded as leucine aminopeptidase (LAP) bound to intracytoplasmic membranes.
Netropsin increases formation of mRNA coding for a neutral metalloproteinase in Bacillus megaterium
Authors: Chaloupka J. , Kučerová H.
Published: February 2007

The anticancer drug netropsin increases the synthesis of an exocellular metalloproteinase during exponential growth as well as in the stationary phase of a sporulating strain of Bacillus megaterium. Its effect is due to a stimulation of the synthesis of the mRNA coding for the proteinase, determined as a residual synthesis of the enzyme in the presence of actinomycin D. The half‐life of the proteinase mRNA (5–6 min at 35 °C) is not affected by netropsin. Netropsin relieves partially the repression of the proteinase mRNA caused by amino acids, whereas the repression brought about by an increased temperature is almost unaffected by the drug.
NADP+‐dependent aldehyde dehydrogenase from ‘Acetobacter rancens’ CCM 1774: Purification and properties
Authors: Hommel Rolf , Kurth Jochen , Kleber Hans‐Peter
Published: February 2007

NADP+‐dependent aldehyde dehydrogenase from the cytosolic fraction of the alkane‐degradating ‘Acetobacter rancens’ CCM 1774 was purified 112‐fold (specific activity of 112 nkat mg−1 protein). After polyacrylamide gel electrophoresis of the purified enzyme only one band was visible. The relative molecular weight was estimated to be 82,000 by both gel filtration and disc gel electrophoresis. The substrate specifity of the purified enzyme within the straight chain aliphatic aldehyde series is confined to acetaldehyde and propionaldehyde. Butyraldehyde and formaldehyde are considerably less converted. NADP+ alone served as electron acceptor. Mg2+ stimulated the reaction velocity in a strong manner by ‘non‐competitive’ activation. The estimation of kinetic parameters and inhibition experiments of the irreversible oxidation of ethanal indicate a random kinetic mechanism at optimal aldehyde concentrations and saturating NADP+ concentrations at optimal pH 8.5 which, however, trends to become ordered with decreasing pH values. Properties described exclude the participation of the enzyme in degradation of n‐alkanes. One physiological function of this constitutive aldehyde dehydrogenase may be the intracellular detoxification of short chain aldehydes by conversion to corresponding fatty acids.
Stepwise increase of elongation rate in individual hyphae of Streptomyces granaticolor during outgrowth
Authors: Kretschmer S.
Published: February 2007

Starting with germinating spores of Streptomyces granaticolor, the kinetics of elongation of 3 types of outgrowing hyphae was determined. The 3 hyphal types were: first germ tube, second germ tube (which appeared from the same spores about 3 hours later) and branches arising from the first germ tubes. Taking photographs every fifth minute, with all hyphae a linear multiphasic elongation behaviour was found. Alternatively, periods with constant elongation rate (α) changed with steps at which α increased abruptly. Several successive shifts were observed until finally at a hyphal length of about 25 μm a constant maximum α of about 22 μm h−1 was attained.

The length of the periods during which α remained constant did not depend on either the hyphal type or the order of the period. On an average, a single period lasted 46.8 minutes.

The lengths of the hyphae, at the time when α increased, corresponded for the first germ tubes to successively about 2,4,8 and 16 unit cells. With branches and second germ tubes these lengths corresponded to 4 and 10 unit cells.

Concerning increase of α during each step the quotients were in the range between 1.3 and 2.0. Branches and second germ tubes started with twice the rate observed with first germ tubes and thus reached the maximum α after a reduced number of steps. Calculations indicated, that on principle α of each linear period was determined by the number of unit cells (nucleoids) present at its beginning.
A simple method of distinguishing the bacterial viruses T3 and T7, and a critical reevaluation of their heterologous and homologous exclusion
Authors: Krüger D. H. , Mann W. , Hansen S. , Bläsing G. , Bläsing M. , Schroeder C.
Published: February 2007

A method is presented allowing a clear distinction between bacterial viruses T3 and T7 by plating on selectively permissive host cells. The indicator strains are Escherichia coli cells containing either cloned pif genes (exclusively permissive for T3) or the EcoRV DNA restriction system (permissive only for T7): The efficiencies of plating of the two phages on these hosts differ by more than 8 orders of magnitude. This method was applied to reinvestigate the controversial question of mutual exclusion between T3 and T7. Under single‐burst conditions, about 50% of coinfected cells (permissive for both viruses) produced T3 and T7 progeny while about 25% reproduced only T3 and about 25% only T7. The burst size of co‐infected cells was slightly reduced, compared to controls infected with only one virus type. Homologous exclusion among T3 phages was also not seen; rather, there was a gene dosage effect: T3‐encoded RNA polymerase activity as well as T3‐specific RNA synthesis increased proportionally to the multiplicity of infection (2.5–20 plaque‐forming units/cell).
Energy conservation in whole cells of the acidophilic methylo‐trophic bacterium Acetobacter methanolicus sp. MB 70
Authors: Loffhagen N. , Babel W.
Published: February 2007

Hitherto, lower growth yields were found with acidophilic methylotrophic bacteria, than those found with neutrophilic methylotrophic ones. Since differences with respect to the oxidative phosphorylation might be responsible for this phenomenon, P/0 quotients were determined for the oxidation by Acetobacter methanolicus sp. MB 70 of endogenous substrates, methanol and other substrates. P/0 quotients for endogenous substrates were calculated from the formation of “energy‐rich” phosphate bonds and the concomitant oxygen uptake on transition of the cells from anaerobiosis to aerobiosis in the range between 0.07 to 0.17 nmol P/nmol 0. P/0 quotients for methanol between 0.1 to 0.25 were determined under aerobic conditions by intracellular energization. For this purpose, the energy charge was decreased to values lower than 0.5 by changing the extracellular pH from 4.0 to 7.0, and increased again to values from 0.7 to nearly 1.0, by adding methanol. The addition of FCCP and DCCD2) totally prevented the increase of the ATP concentration. The energization of the same cell preparation produced similar P/0 quotients for methanol, ethanol and glucose. But in a certain cell preparation, the P/0 quotient for glucose (0.01) was considerably lower than that for methanol (0.18); this was the only quotient reduced from 0.12 to 0.05 by aerating the former cell preparation for 4 h. The results are discussed in terms of the coupling of dehydrogenase reactions, for endogenous and exogenous substrates, to the cytochromes of the respiratory chain. Its composition and structure before cytochrome c appears to be responsible for the fact that the growth yields of these bacteria are smaller than expected for such a type of methylotrophs.
Purification and analysis of DNA‐binding proteins from Streptomyces hygroscopicus
Authors: Sarfert Eva , Zimmer Christoph , Gumpert Johannes , Störl Joachim
Published: February 2007

Purification by DNA‐cellulose chromatography of acid‐soluble DNA‐binding proteins (ASB) from Streptomyces hygroscopicus is described. Two main fractions, ASBII and ASBIII, containing different major protein components were isolated. The dominating protein of ASBIII (19 kd) could be enriched on Streptomyces DNA‐cellulose.

DNA‐binding properties of ASBIII were studied by using a filter retention assay, thermal melting, and by following the DNA template activity in the RNA polymerase system of E. coli. Binding to supercoiled and linear pBR322 DNA occurred effectively at 0.05 M NaCl while increasing salt concentrations up to 0.15 M and 0.2 M NaCl caused dissociation of the complexes. Single‐stranded DNA showed a slightly lower affinity for the ASBIII protein. ASBIII blocked the DNA template activity of the RNA polymerase reaction in vitro. The binding properties and role of ASB‐proteins are discussed with respect to their possible influence on the chromosomal state of the DNA.
The molecular genetics of copper resistance in Saccharomyces cerevisiae — a paradigm for non‐conventional yeasts
Authors: Fogel Seymour , Welch Juliet W. , Maloney Daniel H.
Published: February 2007

After a short introduction on the historical background of the development of Saccharomyces cerevisiae as a model eukaryote, a review is given on the present state of genetics and molecular biology of copper resistance in S. cerevisiae. The gene CUP1 encodes a protein (copper metallothionein) of a molecular weight of 6570 dalton. The synthesis of this copper chelatin is induced by copper and is regulated at the level of transcription.

Copper resistance (CUPr) is correlated with amplification of CUP1 and resulted in a higher copy number of this gene on chromosome VIII. Spontaneous meiotic alterations of the gene copy number have been studied.
Towards diacetyl‐less brewers' yeast. Influence of ilv2 and ilv5 mutations
Authors: Gjermansen Claes , Nilsson‐Tillgren Torsten , Petersen Jens G. Litske , Kielland‐Brandt Morten C. , Sigsgaard Poul , Holmberg Steen
Published: February 2007

During alcoholic fermentations, the off‐flavour compound diacetyl is formed non‐enzymatically from acetolactate leaking out from the cells. Acetolactate is an intermediate in the biosynthesis of valine. In beer fermentation, the amount of diacetyl is reduced to acceptable levels during maturation. A reduction of the time needed for maturation may be achieved by the use of a brewing yeast that produces less diacetyl.

Saccharomyces cerevisiae laboratory strains with an inactive ilv2 gene can not form acetolactate, while ilv5 strains, blocked in the subsequent step, leak acetolactate in high amounts.

Induction of recessive mutations in production strains of Saccharomyces carlsbergensis has not yet been achieved, as the yeast is polyploid and possibly a hybrid between S. cerevisiae and another Saccharomyces species. Thus, all chromosomes investigated so far are present in at least two genetically different versions. Genetic and molecular analysis has shown that the brewing yeast is structurally heterozygous for ILV2 and ILV5.

Genetic modification of brewers' yeast to reduce diacetyl formation is being carried out by mutation of ILV2. Deletion mutations in both ILV2 alleles have been constructed in vitro to be used for gene replacement in the brewing strain. In addition, partial inactivation of the ILV2 function is carried out by selecting spontaneous dominant mutations resistant to the herbicide sulfometuron methyl. Among these mutants some produce only half the amount of diacetyl compared to the parental strain.

An alternative way to reduce diacetyl production might be to increase the activity of the ILV5 gene product. Model experiments in S. cerevisiae show that the presence of the ILV5 gene on a 2‐micron based multi‐copy vector can reduce the diacetyl production by half.
Mating in the alkane‐utilizing yeast Yarrowia lipolytica
Authors: Weber H. , Kurischko Cornelia , Barth G.
Published: February 2007

Mating in Yarrowia lipolytica can be induced by mixing cells of both complementary mating types (A and B) in yeast extract‐malt‐medium. By means of an inbreeding programme, strains with significantly improved mating frequencies were selected. The main events of the mating process, that have been detected so far, by means of cytological methods, are: formation of mating tubes, cell contact, cell fusion and karyogamy. During the process of conjugation, mating tubes of different lengths as and shapes are formed between haploid parental cells. Under special conditions the preformation of mating tubes was observed. Mating in the dimorphic yeast Y. lipolytica has been shown to be a distant mating and to occur between cells of a different shape and size. Cells involved in conjugation are no changed morphologically, except for the formation of special copulation structures. Several events of mating and the morphology of zygotes are different than those in the case of baker's yeasts. It is supposed that there is in this yeast also an action of diffusible factors that trigger mating.
OFAGE banding patterns of different yeast genera and of intergeneric hybrids
Authors: Zimmermann M. , Hoffmann‐Hintz M. , Kolvenbach M. , Emeis C. C.
Published: February 2007

Electrophoretic karyotypes of yeasts belonging to the species Saccharomyces cerevisiae, Kluyveromyces marxianus and Candida macedoniensis were established by means of OFAGE. Hybrids between S. cerevisiae and K. marxianus as well as between K. marxianus and C. macedoniensis were analyzed by comparing their OFAGE‐banding‐pattern with the parental banding‐patterns. Thus, evidence for exchanges of intact chromosomes and for chromosomal rearrangements could be gained on a molecular level.
Purification and properties of a glycoprotein acid phosphatase from the yeast form of Yarrowia lipolytica
Authors: López M. Carmen , Domínguez Angel
Published: February 2007

An acid phosphatase from derepressed cells of the yeast form of Yarrowia lipolytica was purified 176‐fold by ammonium sulfate precipitation, chromatography on DEAE‐Sephacel and gel filtration in Biogel A 5‐M. The enzyme is a glycoprotein with a sugar content of 60%. The MICHAELIS constant of the enzyme is 5.5 × 10−4 M for p‐nitrophenyl phosphate as substrate; the isoelectric point estimated by electrofocusing is around 4.6 and the optimum pH is 6.2. Phosphatase activity was destroyed by exposure of the enzyme to 40 °C for 30 min or at pH 3 for 30 min. The purified enzyme shows size heterogeneity within a linear concentration gradient of polyacrylamide (4–20%) which indicates an apparent molecular weight in the range of 90,000–200,000 in the presence of sodium dodecyl sulfate. The heterogeneity of the enzyme is due to its carbohydrate content, as can be demonstrated by gel filtration and by treatment with endoglycosidase H. The carbohydrate‐depleted protein has a molecular weight of 60,000. Aminoacid analysis revealed a high content of aspartic acid, serine, threonine, glycine and alanine. Antibodies against the protein moiety show cross reactivity with the acid phosphatase of Saccharomyces cerevisiae.
High level expression of heterologous proteins in methylotrophic yeast Pichia pastoris
Authors: Sreekrishna K. , Potenz Rica H. B. , Cruze John A. , McCombie William R. , Parker Kathryn A. , Nelles Lynn , Mazzaferro Paul K. , Holden Kathy A. , Harrison Roger G. , Wood Phyllis J. , Phelps Doris A. , Hubbard Cindi E. , Fuke Motohiro
Published: February 2007

Expression of human tumor necrosis factor —α (TNF) and four different TNF analogs has been studied in Pichia pastoris by utilizing the alcohol oxidase gene promoter. TNF expression level in certain transformants accounted for as much as 36% of the soluble protein. TNF expression was stably maintained during high cell density fermentation (100 g dry cell weight/liter) resulting in a TNF production level of 6–10g/liter. TNF contained in P. pastoris cell lysates was biologically active as determined by its cytotoxic effect on murine L‐929 fibroblast cells and the bioactivity was retained for at least 6 months in the lysates stored frozen at −20 °C in the presence of protease inhibitor PMSF. TNF expressed in P. pastoris was recognized by monoclonal antibodies prepared against recombinant Escherichia coli derived TNF. TNF purified from P. pastoris has the expected N‐terminal amino acid sequence and specific activity of 107 units/mg protein. TNF analogs were also expressed at levels comparable to that of native TNF. Three of the four analogs were insoluble when produced in P. pastoris.
Taxonomic studies of Acinetobacter species based on the electrophoretic analysis of enzymes
Authors: Nishimura Yukimasa , Kanzaki Hisanaga , Iizuka Hiroshi
Published: February 2007

Thirty six strains of Acinetobacter, 22 strains from the culture collections and 14 isolates from soil and cotton samples, were examined for the presence of twelve enzymes using polyacrylamide gel electrophoresis. A numerical analysis was carried out on the basis of similarity values obtained from the electrophoretic mobilities of the enzymes. The strains used were divided into four clusters (Z‐1, Z‐2, Z‐3 and Z‐4), and cluster Z‐1 was further divided into three subclusters (Z‐1a, Z‐1b and Z‐1c). The type strains of Acinetobacter calcoaceticus IAM 12087 (ATCC 23055) and Acinetobacter Iwoffii ATCC 15309 were found to belong to subcluster Z‐1a and cluster Z‐4, respectively. The radiation‐resistant strain FO‐1, a new type of acinetobacters, was included in cluster Z‐3. Superoxide dismutase showed clearly distinguishable mobilities among four clusters, and was concluded to be useful in grouping acinetobacters.
Partial characterization of α‐mannosidase from Yarrowia lipolytica
Authors: Vega Rosario , Domínguez Angel
Published: February 2007

An exo‐α‐mannosidase (E.C. 3.2.1.24) was characterized in the yeast form of Yarrowia lipolytica. The enzyme located in a crude particulate fraction of the cell extract is under catabolite repression, has an optimum pH of 6.0, a Km of 0.27 mM with p‐nitrophenyl‐α‐D‐mannopyranoside and is partially inhibited by D‐mannose.

The enzyme is not affected by ethylenediaminotetraacetic acid, several cations (only Zn++ increased its activity in a 25%) or sulphydryl reagents and can be partially solubilized by treatment with digitonine.
Survey of the pSM10 family of streptococcal cloning vectors
Authors: Laplace Frank , Klessen Christian , Malke Horst
Published: February 2007

A survey of the pSM10 family of streptococcal plasmid cloning vectors is provided. These vectors are derived from a macrolide‐lincosamide‐streptogramin B resistance plasmid and include general cloning vectors, shuttle vectors, helper plasmids, expression vectors, gene fusion vectors and phasmids. Besides describing their general properties, this paper also provides their genetic and physical maps.
Amplification of different ColEl plasmids in an Escherichia coli relA strain
Authors: Schroeter A. , Riethdorf S. , Hecker M.
Published: February 2007

Amino acid starved cells of an E. coli relA strain accumulate a large amount of pBR322 plasmid DNA. In this study ColEl related plasmids of different copy number and size including a high copy number plasmid mutant of pBR322 were amplified in a relA strain of E. coli K‐12 under amino acid limitation in order to determine the upper plasmid level in amino acid starved cells. In all cases we measured a 4 to 6 fold increase of the plasmid copy number in comparison to log‐phase cells independent of the size, the number of origins per plasmid molecule or the copy number in log‐phase cells. The plasmid copy number in amino acid starved cells varies from about 200 (pBR322‐dimer) to about 2000 (high copy number plasmid pERIII‐BPL4, see BOROS et al. 1986). Rop+ and rop− plasmids show the same amplification rate under the used conditions.
Effect of soil treatment with sewage and sludge on fungal populations
Authors: Abdel‐Mallek A. Y. , Moharram A. M. , Bagy M. M. K.
Published: February 2007

The effect of soil treatment with sewage and sludge at three doses (1%, 10% and 20% w/w) on its fungal population was studied in vitro. The treatment of soil with sewage significantly increased the count of total fungi after 1 week by the high dose, and after 12 weeks by each of the three doses. Fungi differed in their response to the different doses of sewage: some were promoted and others were inhibited. The count of total fungi was significantly raised by the low dose of sludge after 1 week of soil treatment, and by the medium and the high doses after 12 weeks. Counts of all fungi were significantly increased at certain treatments with sludge, except those of Aspergillus niger (at the high dose after 6 weeks), Fusarium (at each of the three doses after 3 weeks and at the high dose after 6 weeks) and Paecilomyces varioti (by the medium and the high doses after 1 week) whose counts were significantly lower than those in untreated soil.
Ultrastructural characteristics of Claviceps purpurea seed cultures
Authors: Didek‐Brumec Matjana , Jezernik Kristijan , Puc Anka , Sočič Helena
Published: February 2007

Ultrastructural characteristics of optimally developed seed cultures of two morphologically and biochemically different Claviceps purpurea strains were established. The vegetative mycelium of both conidial (L‐17) and mycelial (L‐18) strains was filamentous and consisted of cells with a polynuclear state. Differences between the strains were more expressed in the ultrastructure of the cytoplasm which contained different and numerically more organelles in the strain L‐17 in comparison with the strain L‐18. This conidial strain developed from a parasitic strain retained in submerged seed cultures the ultrastructural characteristics of sphacelia. Seed cultures of both strains were also characterized by large mitochondria with the dense matrix and numerous cristae, which usually did not appeared before the alkaloid production.
Crystalline structures within vacuoles of n‐alkane‐grown Mucor circinelloides: Cytochemical evidence of NAD(P)H oxidase activity
Authors: Fischer W. , Ude J.
Published: February 2007

Crystalline structures of the fungus Mucor circinelloides were investigated substructurally and cytochemically by means of electron microscopy. The crystals, preferably localized within vacuoles and vesicles, are abundant in hyphae grown on n‐alkanes or 1‐decanol. Stripes and spot patterns with different dispositions are evident in the planes of sectioned crystals. Membraneous structures are in close spatial relation to crystalline inclusions.

The crystals reveal NAD(P)H oxidase activity, as demonstrated by the cerium precipitation technique. The amount of reaction product as well as the quantity of reactive inclusions both depend on the carbon source of the nutrient medium. It was demonstrated that the formation of reaction product is insensitive to 1 mM KCN; it depends rather on both NADH and NADPH, with NADPH being the most efficient substrate, p‐chloromercuribenzoate in the incubation medium results in a drastic reduction in the amount of deposited precipitate; this indicates that the observed cerium precipitation is attributed to enzyme activity. Catalase activity was found to be restricted to microbodies.

The accumulation of the reactive, crystalline condensed material on hydrocarbon‐grown hyphae might account for a changed cellular metabolism.