bluuebunny/crossref_metadata_2025 huggingface dataset:
Candida mucifera n. sp.
Authors: Kocková‐Kratochvílová Anna , Sláviková Elena
Published: February 2007

A new yeast, Candida mucifera, isolated from livers of anurans in the forest of Amazonia, is described. This species differs from all recently accepted Candida species in its morphological and physiological properties and in the fact that in sugar liquid media it produces a large quantity of extracellular polysaccharide that is of a gelatinous consistency.
Degradation of 3‐aminophenol by Arthrobacter spec. mA3
Authors: Lechner U. , Straube G.
Published: February 2007

The bacterial strain mA3 capable of utilizing 3‐aminophenol as the sole source of carbon, energy and nitrogen for growth was isolated from an enrichment culture and identified as an Arthrobacter species. Utilization of 0.68 mg ml 3‐aminophenol by batch cultures of this organism was characterized by a specific growth rate (μ) of 0.18 h−1 and a yield coefficient (Y) of 0.60. In chemostat cultures of strain mA3 we determined a critical dilution rate (Dc) of 0.175 h−1 by continuous addition of mineral salt medium with 0.5 mg/ml 3‐aminophenol.

Evidence was obtained that the degradation of catechol by 3‐aminophenol induced as well as non‐induced cells follows the β‐ketoadipate pathway. The excess ammonium ions, originating from 3‐aminophenol degradation and not needed for assimilation were released into the medium. Cells adapted to 3‐aminophenol exhibited a high substrate specificity. Among different aromatic substances tested, only catechol and 3,4‐dihydroxybenzoate could serve as a carbon source for growth. The importance of the meta position of the amino group for the first step of hydroxylation is discussed in connection with the substrate specificity of whole mA3 cells.
Microscopic structure of ineffective alfalfa nodules formed by auxotrophic mutants of Rhizobium meliloti
Authors: Małek Wanda
Published: February 2007

The inoculation of lucerne seedlings with mutants of Rhizobium meliloti (Arg−) requiring arginine resulted in the formation of ineffective nodules. In these nodules bacteria were not released from the infection threads into the nodule cytoplasm. When arginine was provided as a nitrogen source, the nodules became anatomically similar to those induced by the wild type strain and they fixed nitrogen. Effective nodules were induced also by prototrophic forms of revertants and transductants.

The infected cells in the central tissue of the effective nodule were enlarged, whereas uninfected ones of noneffective nodules of Arg− mutants remained small and contained small nuclei and many large starch granules.
Improvement of medium composition by random balance designs
Authors: Recknagel R.‐D. , Bormann E.‐J. , Friedrich W.
Published: February 2007

If the number of potentially relevant compounds which have to be optimally selected is large, then random balance experimentation provides a useful tool for the development of nutrient media.

The object of investigation was a thiostrepton producing Streptomyces strain from our own collection. The thiostreptone formation was increased although we had insufficient information about the physiological needs or regulation aspects concerning the biosynthesis. The medium development was carried out alongside mutation experiments within a limited temporal interval.

Our study shows how a 9‐component medium can be improved by a 6‐point experimental design. At the end of the paper the basic principles for constructing restricted random balance designs are outlined.
Nachweis einer direkten Isomerisierung von Mannose zu Fructose und ihre Bedeutung für den Mannosestoffwechsel von Pseudomonas syringae pv. phaseolicola
Authors: Sauerstein J. , Ramm M. , Schubert K. , Reuter G.
Published: February 2007

The phytopathogenic pseudomonad Pseudomonas syringae pv. phaseolicola possesses an isomerase which converts mannose to fructose. The synthesis of this enzyme is constitutive. The KM value for mannose is 0.02 M. Fe2 +, Mg2 + and Mn2 + ions stimulate the enzyme activity, whereas Cu2 + and Zn2 + iones are inhibitors. Since the enzymes mannokinase and phosphomannose isomerase could not be detected, the isomerase and an inducible fructokinase must have a function in the metabolism of mannose by this bacterium.
Methodische Untersuchungen zur Interferon‐Induktion unter in vitro‐Bedingungen
Authors: Glück Brigitte , Stelzner Axel
Published: February 2007

The procedures generally used for the in vitro induction of interferon exploit fibroblast or leucocyte culture suspensions. Several factors and conditions influencing the capacity for IFN induction were studied, with the following results.

In contrast to previous findings, optimum IFN induction was obtained at 37 °C, rather than 30 °C, when human fibroblasts were induced with 100 μg/ml of Poly (IC). There was a direct correlation between the dose of the inducing agent applied and the amount of IFN produced. Also, the cells were excellently superinducible with metabolic inhibitors like actinomycin D and cycloheximine. In addition, priming procedures enhanced IFN induction in human fibroblasts.

Comparing different cell types with respect to their ability to be induced for IFN production, we found that different cell types show great differences in their inducer sensitivity. Finally, the response of different cell culture systems was highly variable when induced with different compounds.
Production of extracellular enzymes during growth and autolysis of Pycnoporus cinnabarinus
Authors: Gomez‐Alarcon G. , Lahoz R. , Molina D.
Published: February 2007

Changes in cultural parameters and the production of some extracellular enzymes during growth and autolysis of the white‐rot fugus Pycnoporus cinnabarinus have been studied. At the end of the autolytic period (52 days of incubation) the degree of autolysis was greater than 50%. The laccase activity reached its highest value during the growth period, when the level of the carbon source in the medium was still comparatively high. When the fungus was cultivated in the presence of kraft lignin (Indulin AT) 0.05% (w/v), the activity of laccase was 3 times higher than when grown in the absence of lignin. The presence of lignin did not affect the activities of 1,3‐β‐glucanase, exoxylanase and proteases.
An electron microscopic study of alterations in the morphology and permeability of purified Mycobacterium leprae
Authors: Prabhakaran K. , Job C. K. , Harris E. B. , McCormick G. T.
Published: February 2007

This communication reports the association of changes in ultrastructure of Mycobacterium leprae with alterations in its permeability. To study morphologic changes of the organisms under different conditions (of temperature and exposure to NaOH and trypsin), ultrathin sections of the bacteria were cut and examined in an electron microscope. In the untreated bacilli and those washed with trypsin, the cytoplasmic membrane and the cell wall (peptidoglycan layer) remained intact; dapsone showed little effect on diphenoloxidase of the bacteria. M. leprae is unique among mycobacteria in possessing an unusual form of the enzyme diphenoloxidase. The antileprosy drug dapsone is a potent inhibitor of the enzyme, but it does not readily penetrate the bacteria where the cell envelope remains intact. The cell wall of M. leprae exposed to −80 °C or washed with NaOH was partially detached from the cell membrane; dapsone readily penetrated these organisms and inhibited the bacterial enzyme. In the above preparations, the cytoplasmic membrane appeared undamaged and the bacteria remained viable, as evidenced by multiplication in mouse foot pads. At 50 °C, the peptidoglycan layer became completely separated from the membrane and the cytoplasm was partially denatured. These organisms were permeable to dapsone, but were no longer viable. At 100 °C, the structural organization of the bacilli was completely destroyed, and of course, they lost their enzyme activity as well as viability. Evidently, the intact cell wall layer mediates the exclusion of dapsone from M. leprae, and there is no correlation between its viability and permeability. The ultrathin sections also reveal the internal organization and cytoplasmic inclusions of M. leprae, as never before seen.
Beeinflussung der Phagocytose durch verschiedene Kl‐Kapselpräparationen von Escherichia coli
Authors: Sokolowska‐Köhler Wanda , Bollmann Renate , Mehl Michael , Starke Roland , Presber Wolfgang
Published: February 2007

The influence of two different types of Escherichia coli Kl capsule preparation on the phagosytosis of an E. coli laboratory strain (LN 28) by polymorphnuclear leucocytes (PMNL) is described.

Capsule material of E. coli 0 18 and 0 83 was prepared a) from the culture supernatant and b) from a bacterial pellet fraction. When capsule material from the pellet was added to opsonin, before mixing the laboratory strain with the PMNL, it decreased the rate of phagocytosis, compared with untreated opsonin. The preparation from the supernatant of capsule showed no alteration of phagocytosic rate or capacity.

These results are explained by the different chemical compositions of the preparations.
Functional half‐life of the alpha‐amylase mRNA of Bacillus licheniformis
Authors: Tonkova Alexandra , Pazlarová Jarmila , Emanuilova Elka , Stoeva Nelly
Published: February 2007

Some aspects of the regulation of α‐amylase synthesis in Bacillus licheniformis CCM 2205 were investigated. The effect of actinomycin D and chloramphenicol was studied at the level of RNA transcription and translation, α‐amylase synthesis in Bacillus licheniformis CCM 2205 was practically not altered during the first 20 min after the addition of actinomycin D, although RNA synthesis was almost completely blocked. In contrast to RNA polymerase inhibitor, chloramphenicol stopped immediately the synthesis of α‐amylase. By using the least squares method the mean half‐life of α‐amylase mRNA was calculated to range from 7.5 to 8.4 min. The mean half‐life of cell protein mRNA was determined to range from 2.6 to 3.8 min. Having in mind the immediate effect of chloramphenicol on the α‐amylase synthesis, it can be concluded that de novo protein synthesis is required in the case of actinomycin D resistant residual synthesis.
Isolation and characterization of mutants of Trichosporon adeninovorans resistant to 2‐deoxy‐D‐glucose
Authors: Büttner R. , Scheit A. , Bode R. , Birnbaum D.
Published: February 2007

We isolated stable mutants from Trichosporon adeninovorans resistant to 2‐deoxy‐D‐glucose. All mutants were altered in the C‐catabolite repression and produced different amounts of glucoamylase and β‐glucosidase when grown on several carbon sources. In addition to the C‐catabolite derepression of these extracellular enzymes, a repression defect of isocitrate lyase was found.
Ultrastructure of Borrelia burgdorferi in tissues of patients with Lyme disease
Authors: Hulínská Dagmar , Jirouš Jan , Valešová Marika , Herzogová Jana
Published: February 2007

Spirochetal organisms were sought in 18 skin and 4 synovial membrane specimens obtained by biopsy from 22 Lyme disease patients. The presence of spirochetes in body tissues was histologically demonstrated in one patient with lymphadenosis benigna cutis, one patient with acrodermatitis chronica atrophicans and in one patient with active arthritis. The organisms were 5–30 μm long and 0.12–0.25 μm thick, had 8 or 11 flagella arising from both ends of the body, and their ultrastructure was analogous to that of cultured Borrelia burgdorferi strains. They were located intra‐ or perivascularly, or in the collagenous connective tissue of the skin and synovium. This implies that Lyme spirochetes may have a potential to survive in body tissues and cause injury to blood vessels.
Stability and expression of the staphylococcal constitutive macrolide‐lincosamide‐streptogramin B resistance plasmid pE3692 in Staphylococcus aureus and Bacillus subtilis
Authors: Więckiewicz Jerzy , Wójcik Kinga
Published: February 2007

The constitutive MLS resistance plasmid pE3692 (2.4 kb) from S. aureus and pE3692‐9 plasmid derived from pE3692 by in vitro deletion of the small HindIII‐HindIII fragment Sta t (0.3 kb) were introduced into S. aureus RN450 and B. subtilis UOT0277 strains. The pE3692 plasmid was completly stable in S. aureus RN450, however, in B. subtilis UOT0277 this plasmid was segregationally unstable. Deletion of the Sta t fragment from the pE3692 reduced plasmid stability considerably both in S. aureus and B. subtilis host strains. The lower expression of tylosin‐resistance of the erm gene of the pE3692‐9 plasmid in B. subtilis UOT0277 strain was also observed.
Sexual behavior and its pheromonal regulation in ascosporogenous yeasts
Authors: Yoshida Kazuo , Hisatomi Taisuke , Yanagishima Naohiko
Published: February 2007

We reviewed our investigations on sexual behaviors and interactions including sexual cell agglutination and pheromone action mainly in non‐conventional yeasts, Hansenula anomala, H. wingei, Pichia amethionina, P. heedi, P. opuntiae, Saccharomyces kluyveri, S. globosus, S. exiguus, Saccharomycodes ludwigii. The techniques and genetic models including the cassette model and α1‐α2 hypothesis which had been developed largely in S. cerevisiae were applicable to these yeasts in principle. The sexual agglutination was distinctly species‐specific while sex pheromones were cross‐reactive beyond species' barriers. The successful induction of heterothallic strains from homothallic strains in S. exiguus by mutagenesis enabled to the subsequent biochemical and genetical analysis of sexual behavior in the yeast. The phylogenetic consideration on sex differentiation is also included.
Aclacinomycin ZIMET 33352—a new anthracycline antibiotic
Authors: Dornberger K. , Eckardt K. , Ihn W. , Tresselt D. , Schumann G.
Published: February 2007

A new anthracycline, aclacinomycin ZIMET 33352, has been isolated from cultures of Streptomyces spec. AM 33352/NG 3–11.
Detection of an insensitive ornithine‐carbamoyltransferase in strains of Pseudomonas syringae pv. phaseolicola with different phytotoxin‐generating capacities
Authors: Jahn O. , Sauerstein J. , Laplace F. , Reuter G.
Published: February 2007

Independently of their capacity to produce phytotoxins, strains of Pseudomonas syringae pv. phaseolicola contain two ornithine carbamoyltransferases (OCT, EC 2.1.3.3.) which differ in resistance to phaseolotoxin and Orn‐P(O) (NH2)‐NH‐SO3 H (PNSOrn). At 18 °C, the optimal temperature for product formation, the balance of the two types of OCT was shifted in favour of the insensitive type in phaseolotoxin producing strains, and in favour of the sensitive one in strains with little or no toxin production. The results suggest a causal relationship between the existence of an insensitive enzyme and the synthesis of toxins.
Studies on the effect of the fungicide Euparen on cellulose‐decomposing fungi in Egyptian soil
Authors: Abdel‐Kader M. I. A. , Moubasher A. H. , Abdel‐Mallek A. Y.
Published: February 2007

Euparen when applied to the soil at three doses (0.95, 4.75 and 9.5 mg active ingredient N,N‐dimethyl‐N'‐phenyl‐(N'‐fluorodichloro‐methylthio)‐sulfamide per kg dry soil) was generally suppressive to the total count of fungi and several fungal species. Its toxicity persisted to act till after 10 weeks from treatment with the three doses, but after 15 weeks the toxicity was completely alleviated. Trichoderma spp. were the only fungal species that was recovered from soil when Euparen was incorporated into cellulose‐CZAPEKS agar medium at the three doses (4.8, 23.8 and 47.5 ppm). The decomposition of filter paper buried in Euparen‐treated soil was significantly retarded after 1 week of incubation with the high dose. On the other hand, filter paper sprayed with the fungicide at the high dose and buried in untreated soil was decomposed at a significantly lower rate than the control after all experimental periods (15 weeks) in addition to the medium dose after 5 weeks of incubation. The growth and sporulation of Trichoderma viride on filter papers placed on the surface of carbon‐free agar medium and treated with Euparen were partially increased by the low dose, not affected by the medium dose and partially inhibited by the high dose. The colonization of the other test fungi was partially inhibited or even completely eliminated by the three doses. The mycelial dry weight of Trichoderma viride was significantly increased (nearly doubled) by the medium dose and not affected by the other two doses. The mycelial dry weight and endo 1,4‐β‐D‐glucanase production of the other test fungi were toxicated at least by the higher doses.
Keratinophilic fungi of animal and bird pens in Egypt
Authors: Bagy M. M. K. , Abdel‐Mallek A. Y. , Moharram A. M.
Published: February 2007

Samples were collected from 44 pens under animals and birds for the estimation of keratinophilic fungi using the hair‐baiting technique. Thirty‐nine species which belong to eighteen genera were recovered. Chrysosporium, Aspergillus, and Penicillium were the most frequent genera. From keratinophilic fungi, Myceliophthora anamorph of Corynascus sepedonium, Myceliophthora anamorph of Corynascus novoguinensis, Microsporum boullardii, M. gypseum, Trichophyton mentagrophytes and Arthroderma sp. were also recovered in different frequencies.
The effect of inorganic phosphate on the production of avermectin in Streptomyces avermitilis
Authors: Čurdová Eva , Jechová Vendulka , Zima Jiří , Vaněk Zdenko
Published: February 2007

The effect of phosphate on the production of avermectin B1a, growth and utilization of glucose in the course of cultivation of Streptomyces avermitilis on a complex and chemically defined medium has been studied. Phosphate added at the beginning of cultivation at 1–20 mmol/1 did not distinctly affect the production of secondary metabolite. From the results it follows that the biosynthesis of avermectin tolerates high concentrations of phosphate in the medium.
Biotransformation of tryptamine derivatives in mycelial cultures of Psilocybe
Authors: Gartz Jochen
Published: February 2007

Mycelial cultures of Psilocybe cubensis capable of forming psilocybin and psilocin de novo display a high capacity for hydroxylation of tryptamine derivatives at the 4‐position. A specific biotransformation of added synthetic N,N‐diethyl‐tryptamine was found. Thus high amounts of 4‐hydroxy‐N,N‐diethyltryptamine (up to 3.3%) and a minor quantity of 4‐phosphoryloxy‐N,N‐diethyltryptamine (0.01–0.8%) were isolated from fruiting bodies of Psilocybe cubensis in corresponding experiments. This is the first example of a directed biosynthesis of tryptamine substances by fungi.

An effective biotransformation of N‐methyltryptamine was also demonstrated with surface cultures of Psilocybe semilanceata. Baeocystin, a possible natural precursor of psilocybin, was detected and quantified in the biomasses.

No alkaloids could be found in the culture medium.
Cellular fatty acids composition of the genus Monascus
Authors: Nishikawa Jiro , Sato Yasuhiro , Kashimura Jun , Iizuka Hiroshi
Published: February 2007

The cellular fatty acid composition of the genus Monascus (13 spp., 2 var., 36 strains) was analyzed by gaschromatography. The fatty acid composition of all tested 36 strains shows high similarity. The major components of fatty acids are C18:1, C18:2, C16:0, C18:0, and C16:1.

No strict correlation between the characteristics of the genus Monascus and the fatty acid composition could be found. However, some strains differ from the others. These results suggested that the fatty acids composition ratio could also be a powerful method for taxonomic studies. Moreover, the fatty acid compositions of all Monascus spp. were clearly different from those of Aspergillus oryzae IAM 2600, A. niger IAM 2020, Penicillium notatum IAM 7168 and Paecilomyces variotii IF0 4855.
Monovalent cation specificity of passive transport mediated by laidlomycin and 26‐deoxylaidlomycin
Authors: Gräfe U. , Reinhardt G. , Miosga N.
Published: February 2007

The capacity of laidlomycin (I) and the new 26‐deoxylaidlomycin (II) to facilitate passive fluxes of cations through a layer of organic solvent (CHCl3/n‐heptane) was estimated in comparison to monensin A (III). While II displayed a 10fold higher transport rate for sodium as compared to calcium, laidlomycin (I) was distinguishable by mediating approx. 100times lower conveyance of the divalent cations.
Physical maps of the streptococcal bacteriophage A25 and C1 genomes
Authors: Pomrenke Mary E. , Ferretti Joseph J.
Published: February 2007

A physical map of the group A streptococcal bacteriophage A25 genome was constructed using data obtained from restriction enzyme digestion analysis of purified DNA. Phage A25 was 34.6 kb in size and was digested with several enzymes which generated the following number of fragments: AvaI (3), EcoRI (2), HindIII (4), HaeII (10), HindII (22), HpaI (11), and PvuII (8). Restriction enzymes BamH1, PstI, and SalI did not cleave phage A25 DNA. A physical map of the group C streptococcal phage C1 genome was also constructed. Phage C1 was 16.9 kb in size and was cleaved by the following enzymes to give the indicated number of fragments; EcoRI (8), HaeII (4), HaeIII (10), HindIII (5), HpaI (8), PvuII (3). and SalI (2). Restriction enzymes AvaI, AvaII, BamH1, EcoRV, HpaII, and PstI did not cleave phage C1 DNA.
Production of extracellular trypsin and chymotrypsin inhibitors by aStreptomycessp
Authors: Kourteva Yordanka , Angelova Blaga , Peretz Valya
Published: February 2007

The production of extracellular inhibitors byStreptomycessp. 1–72, specific either to trypsin (TI‐1), or to chymotrypsin (CI‐1), was investigated in relation to the cell growth and composition of the cultivation media. The biosynthesis of the inhibitors was found to be of a growth‐associated type which reached a maximum level at late exponential phase. All of the investigated carbon sources, including starch, disaccharides and monosaccharides, equally supported the production of both inhibitors, while the effect of the different nitrogen sources considerably varied, some of then being totally ineffective. The sources which mostly supported the biosynthesis of the inhibitors were tryptone (3%) for TI‐1, and peptone (3%) for CI‐1 respectively.
Keratinophilic fungi associated with rabbit claws in Egypt
Authors: Moharram A. M. , Abdel‐Gawad K. M.
Published: February 2007

Using the soil plate technique, thirty one species appertaining to twenty three genera were recovered from 160 samples of rabbit claws which were collected from a rabbit farm at Assiut. Of the true keratinophilic fungi Chrysosporium tropicum was the most prevalent where it colonized 56.25% of the samples.

Microsporum gypseum was rarely isolated in this study. Among the non‐keratinophilic fungi Penicillium funiculosum, P.jenseni and Paecilomyces lilacinus were of low incidence (20%, 19.37% and 14.37% of the samples, respectively).
Resistance of Escherichia coli to nourseothricin (streptothricin): Reduced penetrability of the cell wall as an additional, possibly unspecific mechanism
Authors: Seltmann Guntram
Published: February 2007

The resistance of E. coli strains to the antibiotic nourseothricin is known to be caused by an acetyltransferase acetylating the β‐lysine chain of the antibiotic. In addition, most of the resistant strains exhibit reduced penetrability of the outer membrane, presumably caused by a reduced amount of available negative charges. This was shown using crystal violet, Congo red, or the hydrophobic antibiotic novobiocin as indicators.
Coronatine production by Pseudomonas syringae pathovars: Screening method and capacity of product formation
Authors: Völksch Beate , Bublitz Friedemann , Fritsche Wolfgang
Published: February 2007

The hypertrophy of potato tuber tissue caused by coronatine could be developed into a semiquantitative screening method. A correlation between coronatine concentration and hypertrophy was demonstrated. 53 strains of P. syringae pv. glycinea and 9 strains of P. syringae pv. tomato were tested for coronatine production using this method. 24 of the investigated Pseudomonas syringae pv. glycinea strains failed to produce detectable amounts of coronatine. The remaining 29 produced coronatine in various quantities. The yields of these strains differed in orders of magnitude. The strains of P. syringae pv. tomato showed an analogous behaviour.

It is assumed that coronatine is a virulence factor, which is of importance for the severing of plant diseases, implicated in the establishment of the bacteria in the plant tissue.
Induction of akinete formation in Nodularia spumigena by temperature
Authors: Pandey Rakesh Kumar
Published: February 2007

A synchronized akinete differentiation occurred within 3 days when Nodularia filaments were incubated at a higher temperature (32 ± 1 °C). Exogenous nitrogen and carbon compounds increased the akinete frequency. The cyanophycin content of akinetes was found to be nearly 6 times higher than that of exponentially growing vegetative cells. The results suggest that the akinete differentiation is induced by the rise in temperature and akinete frequency is regulated by cellular carbon and nitrogen levels.
Acetohydroxyacid synthase from Claviceps purpurea: Partial purification and characterization
Authors: Maier Walter , Luthra Rajesh , Gröger Detlef
Published: February 2007

An acetohydroxyacid synthase (EC 4.1.3.18) which synthesizes α‐acetolactate from pyruvate has been isolated from two different Claviceps purpurea strains. A purification of about 142‐fold was achieved by ammonium sulfate fractionation and the use of Sepharose 6B and DEAE‐Sepharose CL‐6B columns. The purified enzyme requires thiamine pyrophosphate and a divalent metal ion (Mn2 + or Mg2 +) for maximum activity but no FAD. The optimum pH is about 6.0 and the optimum temperature is 40 °C. The enzyme is not inhibited by branched‐chain amino acids neither singly nor in combination. AHAS is strongly inhibited by p‐chloromercuribenzoate and N‐ethylmaleimide. The apparent Km values for pyruvate and TPP are 1.7 × 10−2 M and 1.2 × 10−6 M, respectively.
Fungal flora of poultry feedstuff ingredients
Authors: Moharram A. M. , Abdel‐Gawad K. M. , Megalla S. E. , Mahmoud A.‐L. E.
Published: February 2007

One hundred and ten samples representing five types of poultry feed ingredients were mycologically examined. These samples included soybean meal, ground maize, cotton‐seed cake, wheat bran and fish meal (22 samples each). Among the 73 mesophilic fungal species, Aspergillus flavus, A. niger and A. fumigatus were the most dominant. A. terreus, A. flavipes, Mucor circinelloides, Scopulariopsis brevicaulis, Penicillium chrysogenum, Fusarium moniliforme and Rhizopus stolonifer were found to be common on a particular ingredient and less common on the remainders. Of the twelve thermophilic and thermotolerant species, A. fumigatus, Thermomyces lanuginosus, Rhizomucor pusillus and Thermoascus thermophilus prevailed on one or more type of the different ingredients. Marked variations were observed in the rancid fatty compounds of the different samples and the values ranged between 0.663 and 3.900 mg malonaldehyde per kg sample.
Comparaison du mode d'infection et du développement des nodosités racinaires et caulinaires chez quelques légumineuses des genres Sesbania et Aeschynomene
Authors: Ramaroson Esthel , Schramm Michael
Published: February 2007

Sesbania rostrata and fifteen species of Aeschynomene are tropical legumes which can grow in flooded soils because they have both root and stem nodulation. They are of particular agronomic interest because of their potential for maintaining soil fertility. Three genera of rhizobia are associated symbiotically with these stem nodulating legumes: Rhizobium infects S. rostrata and some Aeschynomene species; Azorhizobium is specific to S. rostrata and can live outside the plant; Bradyrhizobium infects only Aeschynomene species.

In S. rostrata root infection occurs by root hair curling, whereas stem nodulation is achieved by entry of bacteria at the site of emerging adventitious rootlets. Many studies have reported that infection by thread formation is observed on both roots and stems of S. rostrata.

In S. rostrata, the process of root infection has been shown to follow several stages: recognition and attachment of rhizobia to the root surfaces induction of root hair curling; formation of infection threads that guide bacteria to the adjacent cortical root cells; release of bacteria into the cytoplasm of host cells where they are enveloped by host plasmalemm.

Stem infection of S. rostrata has been shown to have four stages: rhizobial penetration in degenerated cortical cells through cracks at the site of emerging rootlets; Rhizobium proliferates in the intercellular cavities and initiates meristematic nodules; infection threads form in the intercellular cavities and in the host cells; rhizobia are intercellularly released by an endocytotic process.

Most of the stem nodulated Aeschynomene spp. have displayed the same process of root infection as S. rostrata. A.indica is an exception in that it appears that the path of infection is constituted by the rupture of tissue restricted to the place of rootlet emergence. No infection thread formation is observed in A. indica.

The unique characteristic of all stem‐nodulating legumes is the presence of pre‐determined nodulation sites on their stems. In Aeschynomene, the process of stem infection does not involve formation of infection threads but is effected by penetration of Rhizobinum through cracks which surround the root primordia. This penetration is followed by hydrolysis of host epidermic cell walls causing the release of the bacteria into cell cytoplasm.

Stem‐nodulating legumes infection depends on both ecological and intrinsic legumes factors.

It is important to note that the nitrogen fixation of S. rostrata. A. afraspera, and A. scabra was not inhibited by mineral nitrogen.

The role of leaghemoglobin in the regulation and protection of nitrogenase activity is well established. Recently, it was suggested that superoxide dismutase. which is present at high levels in bacteroides isolated from root and stem nodules of a few stem‐nodulating legumes, would be another regulator and protector of the process of nitrogen fixation.
Interferonsensitivität verschiedener Zellkulturen: Untersuchungen zur Abhängigkeit der relativen antiviralen Aktivität vom Interferon‐Subtyp
Authors: Tonew Marion , Glück Brigitte , Ohme Elke , Wondraczek R. H.
Published: February 2007

The phenomenon that rHuIFN‐αl(D) displays an apparently higher antiviral activity when assayed on bovine cells as compared to human cell lines was applied to the elucidation of the nature of recombinant HuIFN prepared in our institute.

These investigations were carried out by using a microtitre test, which defines biological activity as the IFN concentration leading to 50 % inhibition of the cytopathic effect of vesicular stomatitis virus (VSV). In addition, the ability of IFN to diminish the reproduction of infectious viruses was monitored. The two methods yielded similar results. With bovine cells, antiviral activities of the same order of magnitude were observed, regardless of the interferon types applied, i.e. rHuIFN‐αl. rHuIFN‐α2 and human leukocyte interferon. On human fibroblasts, however, rHuIFN‐αl had an apparently 45 to 165 times lower activity than the other two interferons. On human WISH cells, the differences in apparent activity between the respective IFNs were even greater, with factors of up to 212 fold being observed.

Still more distinctive were the effects on murine L 929 cells where an antiviral effect could be confirmed only for rHuIFN‐αl whereas the other two interferons proved completely inactive.
Biochemical aspects of the resistance to nourseothricin (streptothricin) of Escherichia coli strains
Authors: Seltmann Guntram
Published: February 2007

In most cases Escherichia coli strains phenotypically resistant against nourseothricin (streptothricin) harbour a plasmid which codes for an acetyltransferase. This enzyme transfers an acetyl group from acetyl‐coenzyme A to an amino group of the β‐lysine (peptide) chain of the antibiotic, thus inactivating it. Additionally, the penetrability for nourseothricin of the cell wall is drastically reduced in a high percentage of the resistant strains. Both resistance mechanisms seem to be independent of each other.
Microbial biomass protein and polysaccharide production from vegetable processing wastes
Authors: Jwanny Etidal W. , Rashad Mona M. , Moharib Sorial A.
Published: February 2007

Pichia pinus was grown in flasks on extract of mango peel medium. The yield was about 2.5 g of dry yeast cells per liter. The reducing sugar concentration of the medium decreased during the fermentation from a level of about 1.5 to 0.7 gl−1 after 4 days of growth. The value of biomass production after 48 h fermentation was 3 g/g of reducing sugar in the extract of mango peel. The yeast cells contained 66.5 % crude protein. Reasonable amounts of essential amino acids could be estimated. Extracellular polysaccharides formed during fermentation were estimated. The maximum amount found was about 4.8‐5 gl−1 on the 4th day of growth. Chromatographic analysis of the purified polysaccharide hydrolysates revealed the presence of glucose, galactose, arabinose, xylose and an unknown spot near the starting point. The sugar components of exopolysaccharides hydrolysate differed during growing time.
Septation behaviour of the apical cell in Streptomyces granaticolor mycelia
Authors: Kretschmer S.
Published: February 2007

The septation behaviour of the apical hyphal cell, which solely brings about hyphal elongation, was studied using mycelia grown at different specific growth rates (μ) (chemostat and batch cultures). After cell wall staining it was found that both the apical cell (c1) and the adjacent subapical cell (c2) were generally unbranched. Thus, their length (L) could be easily determined.

As the growth rate decreased, Lc1 as well as Lc2 decreased, but cells smaller than 5 μm were not observed, even at extremely slow rates of growth (μ = 0.06 h−1). The largest cells were observed in rich media, where Lc1 attained 4l μm.

Since Lc2 represented the length of one of the new‐born daughter cells of c1, the distribution curves of Lc2 were used to look for regularity of septation. Especially at slow rates of growth, the curves indicated that in c1 septation did not occur randomly. By using Lc2 the interdivision time T of c1 was calculated. At fast rates of growth it was identical to the earlier determined replication time C, indicating that in mature hyphae septation was coupled to the rounds of DNA replication.

Lc1 and Lc2 were used to calculate the length of c1 at birth and at the start of septation. It was found that upon septation the appearing daughter cells were differently sized. Depending on the growth rate, the apically situated daughter cell was 1.37 to 1.81 times larger than the subapical daughter (c2). Based on the functional heterogeneity of the sister cells a hypothesis was invented, which could explain the asymmetric septation pattern. It involves the existence of a period S between the determination of the septum site at median position and the actual process of septum formation. The duration of S was calculated, and its correlation to the T and C values at the corresponding growth rates was discussed. Two mechanisms could be distinguished, which were responsible for the immense increase of Lc1 at fast rates of growth.
Characterization of new resistance plasmids belonging to incompatibility group IncQ
Authors: Tietze Erhard , Tschäpe Helmut , Voigt Wolfgang
Published: February 2007

New IncQ R plasmids, pIE639 and pIE723, are characterized and compared to the prototype IncQ plasmid RSF1010. Additional resistance determinants not common on other R plasmids are located on small stretches of DNA interspacing essential regions at different positions in an otherwise unchanged core of IncQ plasmid DNA. The contribution of IncQ plasmids to resistance evolution in bacteria is discussed.
Characterization of yeasts with high L[+]‐lactic acid production: Lactic acid specific soft‐agar overlay (LASSO) and TAFE‐patterns
Authors: Witte V. , Krohn U. , Emeis C. C.
Published: February 2007

Only few yeast strains are known for the high level production of L[+]‐lactate. We report indications for the conspecifity of Kluyveromyces thermotolerans (formerly Saccharomyces veronae) strain CBS 4728 with Stamm 42 (formerly Saccharomyces pretoriensis, RADLER 1984). We suggest that Stamm 42 has little, if any relationships to Saccharomyces cerevisiae.

Furthermore, we have optimized the method of SUBDEN et al. (1982) for the detection of lactate producing microorganisms. Using this method in a screening with 100 yeast strains of our institute collection, we could not find additional strains with high L[+]‐lactate production. This method may provide a useful tool for the molecular cloning of the unique yeast L[+]‐LDH1) gene (s).
Survey of keratinophilic and saprobic fungi in the clovenhooves and horns of goats and sheep from Egypt
Authors: Abdel‐Hafez A. I. I. , Moharram A. M. , Abdel‐Gawad K. M.
Published: February 2007

Seventy‐six species belonging to 29 genera were collected from 320 samples of cloven‐hooves and horns of goats and sheep.Chrysosporiumwas the most common genus on the various substrates and comprehended the following species:C. asperatum, Chrysosporiumanamorph ofArthroderma cuniculi, Chrysosporiumanamorph ofAnthroderma curreyi, C. georgii, C. indicum, C. keratinophilum, C. lobatum, C. lucknowense, C. pannicola, C. pseudomerdarium, C. queenslandicum, Chrysosporiumstate ofThielavia sepedoniumandC. tropicum.Some interesting fungi were isolated:Myceliophthoraanamorph ofArthroderma tuberculatum, Myceliophthoraanamorph ofCorynoascus novoguineensis, Myceliophthoraanamorph ofCtenomyces serratus, Trichosporon cutaneum, Trichophyton terrestreandT. verrucosum.Also, several saprobic filamentous fungi tolerating high levels of cycloheximide were islolated of which numerous members ofAcremonium, Aspergillus, Chaetomium, Fusarium, Penicillium, Scopulariopsisand serveral others.
Properties of the transducing phage Ml of Rhizobium meliloti
Authors: Malek Wanda
Published: February 2007

A temperate phage Ml, infective towards some R. meliloti strains, was isolated from soil taken from local fields. Its morphology, host range, transducing ability and the locations of restriction endonuclease cleavage sites on the genomes were determined. Phage Ml was classified as belonging to B BRADLEY's group bacteriophages because of the hexagonal outlines of its head and its long, flexible and non‐contractible tail. The molecular weight of phage DNA was estimated to be 54.1 ± 1 kilobases (kb) and it corresponded to the value expected for capsid size – 70 nm. Phage Ml carries out general transduction and forms stable lysogens with the R. meliloti strain L5.30.
Isolation and characterization of an alkaloid‐blocked mutant of Claviceps paspali
Authors: Pertot Elizabeta , Gaberc‐Porekar Vladimira , Sočič Helena
Published: February 2007

After UV‐irradiation an alkaloid‐blocked mutant of Claviceps paspali was isolated from an ergometrine and lysergic acid amides (1:1) producing strain. The formation of ergometrine is blocked in this particular mutant strain which accumulates only lysergic acid amides. A significant morphological differentation of colonies of mutant as well as of mycelium in submerged cultures could be observed and total alkaloid yields are rather influenced.
The occurrence of keratinophilic fungi in sewage sludge from Egypt
Authors: Abdel‐Hafez A. I. I. , El‐Sharouny H. M. M.
Published: February 2007

The keratinophilic fungi of 40 sewage sludge samples from Upper Egypt were studied using a goat hair‐baiting technique. 43 species representing 22 genera were isolated, 17 species of which were dermatophytes and closely related fungi:Chrysosporiumstate ofArthroderma tuberculatum, C. asperatum, C. georgii, C. indicum, C. keratinophilum, C. pseudomerdarium, C. queenslandicum, Chrysosporiumstate ofThielavia sepedonium, C. tropicum, Microsporum cookei, M. gypseum, Myceliophthoraanamorph ofCorynascus novoguineensis, M. vellereaandTrichophyton terrestre.26 species of cycloheximide resistant fungi were collected and these included members ofAcremonium, Aspergillus, Alternaria, Chaetomium, Cladosporium, Cunninghamella, Emericella, Fusarium, Geotrichum, Penicilliumand others.
Formation and regeneration of protoplasts from Gibberella fujikuroi
Authors: Brückner B. , May R. , Loeffler B.
Published: February 2007

The preparation and regeneration of protoplasts from Gibberella fujikuroi was examined. High yields of protoplasts were obtained by using a mixture of lyophilized enzyme preparation from the snail Helix pomatia and a laboratory prepared mycolytic enzyme system from Trichoderma harzianum. The physiological stage of the mycelium and the mycelium amount were found to be important factors in the determination of the protoplast yield. Regeneration could be achieved on the surface of culture media osmotically stabilized with NaCl, KCl, mannitol or sorbitol.
Some physiological studies on fungi isolated from poultry feedstuffs
Authors: Megalla Samuel E. , Nassar A. Y. , Moharram A. M. , Abdel‐Gawad K. M. , Mahmoud A.‐L. E.
Published: February 2007

A total of 506 isolates of mesophilic, thermophilic and thermotolerant fungi isolated from the poultry feed ingredients included soybean meals, ground maize, cottonseed cake, wheat bran and fish meal, on glucose‐CZAPEK's agar, LITTMAN oxgall agar at 28 °C and yeast starch agar (YPSs) at 45 °C, were screened for their ability to produce hydrolytic protease enzyme on solid media. Most of the fungal isolates were able to produce such enzymes but with variable capabilities. The highest proteolytic activity was exhibited by some isolates of Penicillium chrysogenum, Aspergillus flavus, Thermoascus thermophilus and Rhizopus chizopodifarmis. Of all fungal isolates screened for proteolytic activity, Penicillium chrysogenum and Thermoascus thermophilus produced the highest amounts of proteases. These two isolates were used to study the effect of some environmental and nutritional factors on their proteolytic activity. It was found that the highest yield of protease by P. chrysogenum (12.5 units) was achieved 3 days after incubation at 30 °C, Marked reduction in protease activity was observed at 37 °C. The thermophilic fungus T. thermophillus exhibited maximum (18 units) proteolytic activity 6 days after incubation at 45 °C, The enzyme yield was reduced to 13 units at 50 °C. Among the seven carbon sources tested, sucrose was the most appropriate for maximum protease production by both P. chrysogenum and T. thermophilus (13.2 and 12.8 units, respectively). Of the sixteen nitrogen sources investigated. NaNO3 was the best inorganic additive nitrogenous salt which induced the highest proteolytic activity by P. chrysogenum and T. thermophilus, whereas DL‐tryptophan was the most preferable organic nitrogen compound for maximum protease production by the two fungi tested.
Expression and stability of a Rhizobium leguminosarum bv. trifolii Sym plasmid in R. meliloti and Agrobacterium tumefaciens and its effect on clover‐bacterium symbiosis
Authors: Miksch G. , Lentzsch P.
Published: February 2007

The Rhizobium leguminosarum bv. trifolii Sym plasmid pRtr5a was transferred by conjugation to R. meliloti strains deleted or mutated in the nod and fix genes, and also to a plasmid‐less strain of Agrobacterium tumefaciens. The plasmid transfer led to the elimination of the resident cryptic plasmid of the R. meliloti recipients. The Sym plasmid of the recipients was only eliminated in the case of a deletion. In some cases the transferred plasmid was instable. The nod and nif/fix genes of R. leguminosarum bv. trifolii were expressed in R. meliloti and somewhat delayed in A. tumefaciens. A high level of nitrogen fixation on clover was only found in R. meliloti containing pRtr5a. However, this occurred only if the nif/fix genes of the recipient had been deleted before. Inoculation of clover with this R. meliloti strain resulted in a higher dry matter production in comparison to clover inoculated with the donor strain.
Construction of an R‐prime plasmid carrying the hup genes of Azorhizobium caulinodans ORS571 and its transfer to and stability in Rhizobium meliloti
Authors: Miksch G. , Lentzsch P.
Published: February 2007

An R‐prime plasmid (pJB3JI‐18) carrying a 10 kb region of Azorhizobium caulinodans ORS571 DNA which codes for uptake hydrogenase activity was isolated from a Km8 derivative of R68.45. R‐prime plasmids were obtained by transferring R68.45 to ORS571, retransferring it to E. coli, and selecting transconjugants for hydrogenase activity by means of a colour test based on methylene blue. The R‐prime plasmid DNA was hybridized with a DNA region which contained the hup genes of Bradyrhiobium japonicum, indicating homology between the heterologous hup genes. Transfer of the R‐prime plasmid to different Hup− mutants restored the Hup+ phenotype. When it was introduced to R. meliloti strains, it maintained its molecular weight and did not affect indigenous plasmids in two of three recipients. In the third recipient cointegrate formation and incompatibility with indigenous plasmids were found.
Kinetics of hemolysin production in bovine group B streptococci
Authors: Griffiths Bertie B.
Published: February 2007

Thirteen strains of group B streptococci etiologically related to bovine infections were investigated in order to observe the effects of non‐hemoglobin iron and glucose on growth and hemolysin production; and to determine the necessity to stabilize the hemolysin with a carrier‐stabilizer agent. Ferric citrate was diluted to give final concentrations of 1–11 μg/ml, added to iron‐reduced (by CaCl2 precipitation) brain heart infusion media, inoculated and incubated at 37 °C. Parallel experiments were carried out with glucose. A variety of agents was employed to act as hemolysin stabilizers. Hemolysin production was detected by lysis of sheep erythrocytes. Both iron and glucose were crucial in concentrations 5–7 μg/ml and 0.5–1% respectively. Bovine serum albumin‐starch mixture acted as an excellent stabilizer.
Bacillus thuringiensis insecticidal delta‐endotoxin: Diversity of crystal proteins and its relatedness to the toxicity spectrum
Authors: Haider M. Z. , Mahmood S.
Published: February 2007

Bacillus thuringiensis strains produce crystal delta‐endotoxins which exhibit a diverse toxicity spectrum. In order to explore the basis of toxin specificity, a comparison of the activity of 13 strains belonging to seven serotypes was made against three insect species. The delta‐endotoxin crystals were purified and their poly‐peptide composition analyzed by SDS‐PAGE. Among the strains studied, the delta‐endotoxins consist of a variety of crystal proteins in the 60‐144 KDa size range. On the basis of molecular mass, endotoxins maybe grouped into two classes; one contained both high (125‐144 KDa, P1) and medium sized (60–66 KDa, P2) proteins and a second class consisting of only the high Mr polypeptides. Immunoblotting with B. alzawai P1 antiserum revealed antigenic cross‐reaction with one or more of the polypeptides in 125‐144 KDa range in all the strains studied. When the crystal proteins from different strains were immunoblotted with kurstaki P2 antiserum, none of the P1 protein crossreacted suggesting that the P1 and P2 proteins are not structurally related. However, the B. kurstaki P2 antiserum crossreacted with 66 KDa proteins in some other strains which underlines a structural homology in this class of the toxic polypeptides. Toxicity studies revealed that the high Mr P1 proteins of all the strains in this study were active against lepidopteran (Pieris brassicae and Diacrisia obliqua) larvae. B. thuringiensis aizawai strains exhibit a dual toxicity associated with the high Mr (130–135 KDa; P1) proteins. The P2 crystal proteins (60–66 KDa) also showed dual toxicity against the lepidopteran and dipteran larvae but were found to be structurally and immunologically distinct.