Substrate Locking Promotes Dimer-Dimer Docking of an Enzyme Antibiotic Target

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Effects of habitat simplification on assemblages of cavity nesting bees and wasps in a semiarid neotropical conservation area

Habitat complexity is directly correlated to insect diversity in most natural environments. Structural complexity reflects an increase in vertical stratification and plant diversity and often leads to a greater availability of floral resources and nesting sites. Efficient conservation strategies require understanding of how changes in habitat structure affect insects that provide essential ecosystem services. We analyzed how the diversity and species composition of bees and wasps that nest in pre-existing cavities is affected by habitat complexity. Our study was developed in the semiarid region of northeastern Brazil, in the Ubajara National Park and surrounding area. Four types of habitats within two physiognomies were sampled for two consecutive years. We used 120 trap-nest (9000 cavities) distributed in 40 sample points. Overall, 657 cavities were occupied by 11 species of bees, nine of wasps, and six of cleptoparasitic/parasitoids. Bees and wasp diversity increases with habitat complexity. While species richness was higher in more complex physiognomies, abundance was higher in disturbed areas. Species composition also varied with habitat structure. Habitat simplification has adverse effects on the diversity and composition of assemblages. These effects are stronger in more complex habitats indicating that conservation of humid habitats within semiarid areas is essential to maintain bee and wasp regional diversity.     

Genomic compositions and phylogenetic analysis of Shigella boydii subgroup

Comparative Genomic Hybridization (CGH) microarray analysis was used to compare the genomic compositions of all eighteen Shigella boydii serotype representative strains. The results indicated the genomic “backbone” of this subgroup contained 2552 ORFs homologous to nonpathogenic E. coli K12. Compared with the genome of K12199 ORFs were found to be absent in all S. boydii serotype representatives, including mainly outer membrane protein genes and O-antigen biosynthesis genes. Yet the specific ORFs of S. boydii subgroup contained basically bacteriophage genes and the function unknown (FUN) genes. Some iron metabolism, transport and type II secretion system related genes were found in most representative strains. According to the CGH phylogenetic analysis, the eighteen S. boydii serotype representatives were divided into four groups, in which serotype C13 strain was remarkably distinguished from the other serotype strains. This grouping result corresponded to the distribution of some metabolism related genes. Furthermore, the analysis of genome backbone genes, specific genes, and the phylogenetic trees allowed us to discover the evolution laws of S. boydii and to find out important clues to pathogenesis research, vaccination and the therapeutic medicine development.     

Diet of Neotropical parrots is independent of phylogeny but correlates with body size and geographical range

Body mass and geographical range are two main drivers of diet in animals, yet how these factors influence diet in the morphologically and ecologically diverse avian group of Psittaciformes is little known. We reviewed current knowledge of the diet of Neotropical parrots and assessed the relation between diet (breadth and composition), phylogeny, body mass and geographical range. Diet has been documented for 98 of 165 species, but information is available only for 34 of 59 threatened species, and countries with high species diversity (> 20 species) had few studies (one to seven). Neotropical parrot species consumed 1293 plant species of 125 families. When assessing the relative frequency of different food items in the diet (seed, fruits, flowers, leaves, nectar, bark and stems), we found that parrots mostly exploited seeds (41.9%) and fruits (38.3%) of native species. Diet overlap was very low among genera (0.006–0.321). At the species level, geographical range and body size explained the variation in diet composition. In particular, small parrots of restricted distribution had a distinct diet composition relative to either large or widely distributed species. Although body size and geographical range showed phylogenetic inertia, diet was independent of phylogenetic history. Our review not only reveals ecological factors explaining diet in a generalist group but also exposes information gaps across the Neotropical region.     

The Effects of the Organic Flame‐Retardant 1,2‐Dibromo‐4‐(1,2‐dibromoethyl) Cyclohexane (TBECH) on Androgen Signaling in Human Prostate Cancer Cell Lines

The effects of the organic flame retardant 1,2‐Dibromo‐4‐(1,2‐dibromoethyl) cyclohexane (TBECH) on androgen receptor target gene expression were examined in the human LNCaP prostate cancer cell line. While γ‐/δ‐TBECH alone led to a significant increase in prostate‐specific antigen (PSA) mRNA accumulation, both the α‐/‐TBECH and γ‐/δ‐TBECH mixtures repressed androgen‐inducible PSA mRNA and protein accumulation in human LNCaP cells. Thus, we hypothesize that isomeric mixtures of TBECH may act as partial agonists of the androgen receptor.