Cellulase production by Rhizobium

Summary The production of cellulase byRhizobium species was studied.Rhizobium trifolii cellulase was induced by a variety of polysaccharides, including celluloses and hemicelluloses. Cellobiose and myo-inositol also allowed enzyme expression but mannitol prevented it at concentrations higher than 0.25%. Both soluble and insoluble plant root substances moderately stimulated cellulase production byRhizobium trifolii.Most substances tested did not induce the production of cellulases by the slow-growing, cowpea type rhizobia strain CIAT 79. Effective inducers were carboxymethylcellulose, gluconate and myo-inositol.Cellulase production was very low under all conditions tested. In most cases the enzyme activity was loosely bound to the capsular material. The enzyme in fast-growers is an 1,4--D-glucan-4-glucanohydrolase (endo-glucanase EC 3.2.1.4) with specificity for high molecular weight polysaccharides.There was no correlation between infectiveness ofRhizobium trifolii strains and cellulase production. One strain, which lacks the nodulation plasmid, produced cellulase at the same rate as its parental infective strain.     

Denaturation of mouse satellite DNA upon melting of chromatin in solution

The denaturation of mouse satellite DNA upon melting of chromatin in solution of low ionic strength has been studied. A procedure for preparation of partially denaturated chromatin was developed which enabled the isolation of double-stranded (non-denatured) DNA sequences according to their thermal stability in chromatin. The content of mouse satellite DNA in these DNA sequences was determined by hybridization with RNA, complementary to satellite DNA in order to find the temperature interval of denaturation of satellite DNA. It was found that the melting temperature of satellite DNA in chromatin was lower than that of the total DNA. The results are discussed in relation to previously reported anomalous behaviour of satellite DNA upon melting of chromatin on hydroxyapatite.     

A major substrate of maturation promoting factor identified as elongation factor 1 beta gamma delta in Xenopus laevis

Protein synthesis is believed to be under control of the cell cycle during meiosis and mitosis. Any relationship between substrates for cdc2 kinase and components of the protein synthetic apparatus would therefore be of prime importance. During meiosis of Xenopus laevis oocytes one of the substrates for this kinase is a p47 protein, which is complexed to two other proteins, P36 and P30. Judged from partial amino acid sequence data on P47 and P30, the P30 and P47 proteins were reported to resemble the protein synthetic elongation factors (EF) 1 beta and 1 gamma from Artemia salina (Bellé, R., Derancourt, J., Poulhe, R., Capony, J.P., Ozon, R., and Mulner-Lorillon, O. (1989) FEBS Lett. 255, 101-104). This paper shows that the complex composed of P30, P47, and P36 from Xenopus is identical to the complex of EF-1 beta, EF-1 gamma, and EF-1 delta from Artemia according to two criteria. 1) Both stimulate elongation factor 1 alpha-mediated transfer RNA binding to ribosomes and exchange of guanine nucleotides on elongation factor 1 alpha to a comparable degree. 2) Each of the three subunits of the protein complex P30.P47.P36 from Xenopus shows a structural homology with one of the corresponding subunits of EF-1 beta gamma delta from Artemia. Presumably the phosphorylation of EF-1 gamma, which associates with tubulin at least in vitro, is important in processes following the onset of meiosis which is accompanied by a rise of protein synthesis.     

The influence of ionic composition on the distribution of nematode species in springs of the province of Granada (Spain)

The ionic composition of 38 mineral springs in the province of Granada (Spain), and the distribution of 45 species of nematodes belonging to orders Monhysterida, Araeolaimida, Chromadorida and Enoplida were examined. Water chemistry is used to make two diagrams representing anionic and cationic composition. Diagrams for anionic composition (given the greater variance seen in the springs considered) are used to illustrate the distribution of individual species. The results obtained from species distribution and the correlation between species made it possible to group species which could be associated with springs where each of the anions considered predominated. A greater number of species groups was found to inhabit springs in which chloride concentrations was less than 50% of the total concentration of anions.     

Structure-activity relationships for unsaturated dialdehydes. 6. The mutagenic activity of 11 compounds in the V79/HGPRT assay.

The mutagenic activity of 11 sesquiterpenoid unsaturated dialdehydes in the V79/HGPRT assay has been determined, and is compared with previously published data on the mutagenicity of the same compounds towards Ames Salmonella strains. One compound, isovelleral, is a potent mutagen in both assays, while six compounds, which are positive in the Ames Salmonella/microsome assay, show no significant activity in this study. One compound, acetylmerulidial, is negative in the Ames Salmonella/microsome assay but significantly although weakly mutagenic in the V79/HGPRT assay. The remaining three compounds are inactive in both assays. The study is part of a general investigation of quantitative structure-activity relationships for unsaturated dialdehydes, a class of natural occurring compounds known for their potent and numerous biological activities.     

Evaluation in Drosophila melanogaster of the mutagenic potential of furfural in the mei-9a test for chromosome loss in germ-line cells and the wing spot test for mutational activity in somatic cells.

The mutagenic potential of furfural was evaluated by means of the chromosome loss test in germ cells and the wing spot test in somatic cells of Drosophila melanogaster. The chromosome loss test was carried out employing repair-proficient as well as repair-deficient females. Males carried the compound Y chromosome, BSYy+. Two routes of administration were used: injection and feeding of adult males. Genetic damage was demonstrable after matings of treated males with females carrying the excision repair-deficient mutant mei-9a. The somatic mutation and recombination test was carried out treating 72-h transheterozygous mwh+/+flr3 larvae. Acute treatment of larvae was chosen as the method of exposure. Evidence indicates that furfural induces somatic damage as measured in the wing spot test.     

Cloning and expression of hepatitis B surface antigen in the yeastKluyveromyces lactis

Summary The gene coding for the major surface antigen of the hepatitis B virus was integrated into the genome ofKluyveromyces lactis and expressed up to levels of 0.4% of the total soluble protein.     

Comparative value of four arcelin variants in the development of dry bean lines resistant to the Mexican bean weevil

Wild Phaseolus vulgaris L. accessions containing arcelin codominant alleles 1 through 5 were reconfirmed and characterized for resistance to the Mexican bean weevil, Zabrotes subfasciatus (Boheman) (Coleoptera: Bruchidae). Accession G 02771 (arcelin 5) had the highest level of antibiosis resistance, followed by G 12952 (arcelin 4), G 12882 (arcelin 1) and G 12866 (arcelin 2). Arcelin 3 accessions conferred the lowest levels of resistance. As the presence of arcelin is inherited as a single dominant gene, a backcross breeding program has been used to transfer resistance to the Mexican bean weevil from wild beans to bean cultivars using serological techniques to detect the presence of arcelin and replicated insect feeding tests to measure resistance levels. Progeny containing arcelin 1 showed resistance equal or superior to that of the resistant check. Arcelin 2-deerived lines had intermediate levels of resistance while no resistant progenies were obtained from crosses with arcelin 3 and 4 sources. Results are discussed in relation to the deployment of arcelin alleles in bean cultivars.

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Valeurs comparées de 5 types d'arcéline dans l'obtention de lignées de Phaseolus vulgaris résistantes à Zabrotes subfasciatus

Résumé La résistance à Zabrotes subfasciatus est associée à la présence d'arcéline, une nouvelle protéine des graines, découverte chez quelques populations de Phaseolus vulgaris. 5 types d'arcéline, hérités comme allèles codominants ont été décrits dans la littérature. Nous avons reprécisé les différentes populations contenant différents types d'arcéline et caractérisé leurs résistances à Z. subfasciatus. La population G 02771, correspondant à l'arcéline 5, présente la résistance la plus élevée par antibiose, suivie de G 12952 (arcéline 4), G 12882 (arcéline 1) et G 12866 (arcéline 2). Les populations contenant l'arcéline 3 présentent le moins de résistance à Z. subfasciatus.Un programme de croisements en retour associé à des tests sérologiques pour déceler la présence d'arcéline chez les descendants jeunes et des expériences répétées d'alimentation par les insectes vec BC2F₃ a été réalisé pour transférer la résistance de populations naturelles à des cultivars de haricots. Les lignées, provenant de croisements avec des populations sauvages avec de l'arcéline 1, ont été fortement résistantes à Z. subfasciatus. Les lignées contenant de l'arcéline 2 ont été considérées comme ayant une résistance intermédiaire. Les lignées avec arcélines 3 et 4 étaient sensibles. Les raisons de l'échec du transfert de la résistance élevée des parents contenant de l'arcéline 4, sont inconnues. On a constaté que la concentration de l'arcéline dans les lignées contenant cet allèle était très faible, tandis que la concentration en arcéline 1 restait remarquablement élevée. Les recherches sont poursuivies pour déterminer les raisons de l'absence de transfert de l'arcéline 4 chez les descendants contenant cet allèle. Quoi qu'il en soit, les caractéristiques agronomiques et les qualités des lignées résistantes (codées RAZ) ont été évaluées en vue d'une diffusion pour les programmes nationaux de recherche des pays de basses altitudes intertropicaux ou Zabrotes subfasciatus fait des dégâts importants.

     

Mammalian wildlife diseases as hazards to man and livestock in an area of the Llanos Orientales of Colombia

Development of the LLanos Orientales of Colombia, and access to underdeveloped areas in the Llanos, may create disease hazards to man and domestic animals or introduce exotic pathogens, creating reservoirs of infection for domestic animals and acting as limiting factors on the native wild species. A survey of wild animals common to the Llanos revealed a number of parasites indigenous to the area. A total total of 59 mammalian species, representing eight orders were examined. Haematozoa were represented by Trypanosoma cruzi, T. evansi and T. rangeli. Eight species of ticks were found: Amblyomma cajennense, A. auricularium, A. rotundatum, A. maculatum, A. longirostre, A. pacae, Ixodes luciae and Boophilus microplus. Four species of fleas were found: Rhopalopsyllus lugubris lugubris, R. australis tupinus, R. cacicus saevus and Polygenis klagesi samuelis. A species of Echinococcus was commonly found in Cuniculus paca. Serologic titers and/or isolations of pathogenic viral and bacterial agents generally indicated that the wildlife population had not been exposed to the diseases common to the domestic population. A low prevalence of titers to Venezuelan equine encephalomyelitis was found in Cebus apella and Proechimys sp. Neutralizing antibodies to Group B viruses were found in Proechimys sp., Coendor sp. and Nectomys squamipes. Antibodies to Group C viruses were found in Proechimys sp. Serologic titers to Leptospira sejroe and L. tarassovi were found in Proechimys sp. and Didelphis marsupialis. L. tarassovi was isolated from Proechimys sp. Titers to Brucella were not found in 1964 animals. The significance of these findings are discussed.     

Treatment of carcinoma in situ of the bladder with BCG

Summary Although carcinoma in situ conveys the idea of an early neoplasm, such lesions in the bladder mucosa commonly exhibit a very aggressive behavior and carry a grave prognosis. Seven patients with in situ carcinoma of the bladder have been treated with intravesical and systemic administration of Bacillus Calmette-Guérin. Elimination of tumor was documented by endoscopy, histology and cytology in five patients. These five patients have remained tumor-free for periods ranging between 12 and 33 months (mean: 22.6). This preliminary study indicates that regional and systemic immunotherapy is an alternative worth additional investigation in patients with carcinoma in situ of the bladder.