ZraP is a periplasmic molecular chaperone and a repressor of the zinc-responsive two-component regulator ZraSR

The bacterial envelope is the interface with the surrounding environment and is consequently subjected to a barrage of noxious agents including a range of compounds with antimicrobial activity. The ESR (envelope stress response) pathways of enteric bacteria are critical for maintenance of the envelope against these antimicrobial agents. In the present study, we demonstrate that the periplasmic protein ZraP contributes to envelope homoeostasis and assign both chaperone and regulatory function to ZraP from Salmonella Typhimurium. The ZraP chaperone mechanism is catalytic and independent of ATP; the chaperone activity is dependent on the presence of zinc, which is shown to be responsible for the stabilization of an oligomeric ZraP complex. Furthermore, ZraP can act to repress the two-component regulatory system ZraSR, which itself is responsive to zinc concentrations. Through structural homology, ZraP is a member of the bacterial CpxP family of periplasmic proteins, which also consists of CpxP and Spy. We demonstrate environmental co-expression of the CpxP family and identify an important role for these proteins in Salmonella's defence against the cationic antimicrobial peptide polymyxin B.     

Effects of landscape matrix on population connectivity of an arboreal mammal,Petaurus breviceps

Ongoing habitat loss and fragmentation is considered a threat to biodiversity as it can create small, isolated populations that are at increased risk of extinction. Tree‐dependent species are predicted to be highly sensitive to forest and woodland loss and fragmentation, but few studies have tested the influence of different types of landscape matrix on gene flow and population structure of arboreal species. Here, we examine the effects of landscape matrix on population structure of the sugar glider (Petaurus breviceps) in a fragmented landscape in southeastern South Australia. We collected 250 individuals across 12 native Eucalyptus forest remnants surrounded by cleared agricultural land or exotic Pinus radiata plantations and a large continuous eucalypt forest. Fifteen microsatellite loci were genotyped and analyzed to infer levels of population differentiation and dispersal. Genetic differentiation among most forest patches was evident. We found evidence for female philopatry and restricted dispersal distances for females relative to males, suggesting there is male‐biased dispersal. Among the environmental variables, spatial variables including geographic location, minimum distance to neighboring patch, and degree of isolation were the most important in explaining genetic variation. The permeability of a cleared agricultural matrix to dispersing gliders was significantly higher than that of a pine matrix, with the gliders dispersing shorter distances across the latter. Our results added to previous findings for other species of restricted dispersal and connectivity due to habitat fragmentation in the same region, providing valuable information for the development of strategies to improve the connectivity of populations in the future.     

Phylogenetic placement of the austral rove beetle genus Hyperomma triggers changes in classification of Paederinae (Coleoptera: Staphylinidae)

Sister‐group relationships are resolved for the systematically and biogeographically puzzling austral rove beetle genus Hyperomma by means of phylogenetic analysis of five gene markers (one mitochondrial and four nuclear protein‐coding) for 25 taxa broadly representing the subfamily Paederinae, and six outgroup taxa from Staphylininae and Pseudopsinae. As a result, the new subtribe Dicaxina subtrib. nov. is established for Hyperomma and five other Southern Hemisphere genera previously classified in Cryptobiina. Based on the molecular phylogeny and the discussion of several adult and larval morphological characters, the concept of the tribe Paederini is changed as follows: Paederini sensu novo is reduced to include Paederina, Cryptobiina, Dolicaonina and Dicaxina only, while Lathrobiini sensu novo is established for Lathrobiina, Scopaeina, Astenina, Stilicopsina, Medonina, Stilicina and Echiasterina. The tribe Cylindroxystini stat. resurr. is reinstated for the Paederini subtribe Cylindroxystina because of its very peculiar morphology not fitting either Paederini or Lathrobiini in new sense. The tribe Pinophilini was resolved as sister to Lathrobiini sensu novo, and its status remains unchanged. Morphological diagnoses and other relevant systematic information are provided for all newly established taxa. The taxonomic history of the higher‐level systematics of the subfamily Paederinae is summarized.     

Plain Women: Gender and Ritual in the Old Order River Brethren.

Plain Women: Gender and Ritual in the Old Order River Brethren. Margaret C. Reynolds. with. foreword by Simon J. Bronner, ed. University Park: Pennsylvania State University Press, 2001. 192 pp.     

Relaxation dynamics in three polypyridyl iron(II)-based complexes probed by nanosecond and sub-picosecond transient absorption spectroscopy

The results of a sub-picosecond transient absorption spectroscopy study on a mononuclear and two dinuclear low-spin iron(II) complexes is reported. The dinuclear derivatives are homonuclear (i.e. Fe–Fe) and heterodinuclear (Fe–Zn) in nature. The ligands we used were 2-pyridylmethyl-ketazine and 2-pyridylmethyl-hydrazone. Irradiation was made on the metal-to-ligand CT band occurring around 500 nm. The observed pattern of the relaxation decays is consistent with the population of the metastable ⁵T₂ ligand field state within the first 100 fs after the photon absorption from the three different chromophores. The suggested implication of triplet intermediate states was not detected. The ground state recovery was observed to occur with a time constant of 350 ps for the mononuclear complex and 1600–1800 ps for the two dinuclear complexes.