Paenibacillus brasilensis sp nov., a novel nitrogen-fixing species isolated from the maize rhizosphere in Brazil

Sixteen nitrogen-fixing strains isolated from the rhizosphere of maize planted in Cerrado soil, Brazil, which showed morphological and biochemical characteristics similar to the gas-forming Paenibacillus spp., were phenotypically and genetically characterized. Their identification as members of the genus Paenibacillus was confirmed by using specific primers based on the 16S rRNA gene. SDS-PAGE of whole-cell proteins, API 50CH, morphological and biochemical tests, amplified rDNA-restriction analysis (ARDRA), DNA-relatedness analyses, denaturing-gradient gel electrophoresis (DGGE) and 16S rRNA gene sequence determinations were performed to characterize the novel isolates and to compare them to strains of other nitrogen-fixing Paenibacillus spp. Phenotypic analyses showed that the 16 strains were very homogeneous and shared a high level of relatedness with Paenibacillus polymyxa and Paenibacillus peoriae. However, none of the novel isolates was able to ferment glycerol (positive test for P. polymyxa), L-arabinose or D-xylose (positive tests for P. polymyxa and P. peoriae) or utilize succinate (positive test for P. peoriae). Genetic approaches also indicated a high level of similarity among the novel isolates and P. polymyxa and P. peoriae, but the novel strains clearly could not be assigned to either of these two recognized species. On the basis of the features presented in this study, the 16 novel isolates were considered to represent members of a novel species within the genus Paenibacillus, for which the name Paenibacillus brasilensis is proposed. The type strain is PB172(T) (=ATCC BAA-413(T)=DSM 14914(T)

Relationship between adiposity and admixture in African-American and Hispanic-American women.

ObjectiveThe objective of this study was to investigate whether differences in admixture in African-American (AFA) and Hispanic-American (HA) adult women are associated with adiposity and adipose distribution.DesignThe proportion of European, sub-Saharan African and Amerindian admixture was estimated for AFA and HA women in the Women's Heath Initiative using 92 ancestry informative markers. Analyses assessed the relationship between admixture and adiposity indices.SubjectsThe subjects included 11 712 AFA and 5088 HA self-identified post-menopausal women.ResultsThere was a significant positive association between body mass index (BMI) and African admixture when BMI was considered as a continuous variable, and age, education, physical activity, parity, family income and smoking were included covariates (P<10(-4)). A dichotomous model (upper and lower BMI quartiles) showed that African admixture was associated with a high odds ratio (OR=3.27 (for 100% admixture compared with 0% admixture), 95% confidence interval 2.08-5.15). For HA, there was no association between BMI and admixture. In contrast, when waist-to-hip ratio (WHR) was used as a measure of adipose distribution, there was no significant association between WHR and admixture in AFA but there was a strong association in HA (P<10(-4); OR Amerindian admixture=5.93, confidence interval=3.52-9.97).ConclusionThese studies show that: (1) African admixture is associated with BMI in AFA women; (2) Amerindian admixture is associated with WHR but not BMI in HA women; and (3) it may be important to consider different measurements of adiposity and adipose distribution in different ethnic population groups

Characterization of Herbaspirillum seropedicae gen. nov., sp. nov., a root-associated nitrogen-fixing bacterium.

During a survey of the occurrence of Azospirillum spp. in cereal roots, we obtained 119 isolates which could not be identified as members of one of the three previously described Azospirillum species. These strains formed a very homogeneous group of N2-fixing, microaerobic, motile, vibrioid, gram-negative rod-shaped organisms which formed a veillike pellicle in semisolid medium similar to that of Azospirillum spp. However, the new isolates differed from Azospirillum spp. by their smaller cell width (0.6 to 0.7 μm), variable flagellation (one to three flagella on one or both poles), moist brownish colonies, and broader pH and oxygen tolerance for nitrogenase activity. Organic acids were the preferred carbon sources, but glucose, galactose, L-arabinose, mannitol, sorbitol, and glycerol were also used. The guanine-plus-cytosine content of the deoxyribonucleic acid was slightly lower than the guanine-plus-cytosine contents of Azospirillum spp. (66 to 67 mol%). Deoxyribonucleic acid hybridization experiments with 17 strains of the group showed 50 to 100% complementarity, while the levels of hybridization with the type strains of Azospirillum brasilense, Azospirillum lipoferum, and Azospirillum amazonense were 23, 15, and 6%, respectively. For these new isolates we propose a new genus, Herbaspirillum (the name refers to the habitat of the organisms, the roots of cereals, which are herbaceous seed-bearing plants). The type species is named Herbaspirillum seropedicae after the place where it was first isolated. The type strain is strain Z67, which has been deposited in the American Type Culture Collection as strain ATCC 3589

Mice lacking sialyltransferase ST3Gal-II develop late-onset obesity and insulin resistance

Sialyltransferases are a family of 20 gene products in mice and humans that transfer sialic acid from its activated precursor, CMP-sialic acid, to the terminus of glycoprotein and glycolipid acceptors. ST3Gal-II (coded by the St3gal2 gene) transfers sialic acid preferentially to the three positions of galactose on the Galβ1-3GalNAc terminus of gangliosides GM1 and GD1b to synthesize GD1a and GT1b, respectively. Mice with a targeted disruption of St3gal2 unexpectedly displayed lateonset obesity and insulin resistance. At 3 months of age, St3gal2-null mice were the same weight as their wild type (WT) counterparts, but by 13 months on standard chow they were visibly obese, 22% heavier and with 37% greater fat/lean ratio than WT mice. St3gal2-null mice became hyperglycemic and displayed impaired glucose tolerance by 9 months of age. They had sharply reduced insulin responsiveness despite equivalent pancreatic islet morphology. Analyses of insulin receptor (IR) tyrosine kinase substrate IRS-1 and downstream target Akt revealed decreased insulininduced phosphorylation in adipose tissue but not liver or skeletal muscle of St3gal2-null mice. Thin-layer chromatography and mass spectrometry revealed altered ganglioside profiles in the adipose tissue of St3gal2-null mice compared to WT littermates. Metabolically, St3gal2-null mice display a reduced respiratory exchange ratio compared to WT mice, indicating a preference for lipid oxidation as an energy source. Despite their altered metabolism, St3gal2-null mice were hyperactive. We conclude that altered ganglioside expression in adipose tissue results in diminished IR sensitivity and late-onset obesity.Fil: Lopez, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina. Johns Hopkins University School of Medicine; Estados UnidosFil: Aja, Susan. Johns Hopkins University School of Medicine; Estados UnidosFil: Aoki, Kazuhiro. University of Georgia; GreciaFil: Seldin, Marcus M.. Johns Hopkins University School of Medicine; Estados UnidosFil: Lei, Xia. Johns Hopkins University School of Medicine; Estados UnidosFil: Ronnett, Gabriele V. Johns Hopkins University School of Medicine; Estados UnidosFil: Wong, G. William. Johns Hopkins University School of Medicine; Estados UnidosFil: Schnaar, Ronald L.. Johns Hopkins University School of Medicine; Estados Unido

Ocorrência de endófitos do gênero Bacillus em seiva de plantas de milho.

bitstream/item/58840/1/ct-35-1.pd