Septin-mediated plant cell invasion by the rice blast fungus, Magnaporthe oryzae

To cause rice blast disease, the fungus Magnaporthe oryzae develops a pressurized dome-shaped cell called an appressorium, which physically ruptures the leaf cuticle to gain entry to plant tissue. Here, we report that a toroidal F-actin network assembles in the appressorium by means of four septin guanosine triphosphatases, which polymerize into a dynamic, hetero-oligomeric ring. Septins scaffold F-actin, via the ezrin-radixin-moesin protein Tea1, and phosphatidylinositide interactions at the appressorium plasma membrane. The septin ring assembles in a Cdc42- and Chm1-dependent manner and forms a diffusion barrier to localize the inverse-bin-amphiphysin-RVS-domain protein Rvs167 and the Wiskott-Aldrich syndrome protein Las17 at the point of penetration. Septins thereby provide the cortical rigidity and membrane curvature necessary for protrusion of a rigid penetration peg to breach the leaf surface.     

Glutamatergic and dopaminergic neurons mediate anxiogenic and anxiolytic effects of CRHR1

The corticotropin-releasing hormone receptor 1 (CRHR1) critically controls behavioral adaptation to stress and is causally linked to emotional disorders. Using neurochemical and genetic tools, we determined that CRHR1 is expressed in forebrain glutamatergic and γ-aminobutyric acid-containing (GABAergic) neurons as well as in midbrain dopaminergic neurons. Via specific CRHR1 deletions in glutamatergic, GABAergic, dopaminergic, and serotonergic cells, we found that the lack of CRHR1 in forebrain glutamatergic circuits reduces anxiety and impairs neurotransmission in the amygdala and hippocampus. Selective deletion of CRHR1 in midbrain dopaminergic neurons increases anxiety-like behavior and reduces dopamine release in the prefrontal cortex. These results define a bidirectional model for the role of CRHR1 in anxiety and suggest that an imbalance between CRHR1-controlled anxiogenic glutamatergic and anxiolytic dopaminergic systems might lead to emotional disorders.     

Paleoindian seafaring, maritime technologies, and coastal foraging on California's Channel Islands

Three archaeological sites on California's Channel Islands show that Paleoindians relied heavily on marine resources. The Paleocoastal sites, dated between ~12,200 and 11,200 years ago, contain numerous stemmed projectile points and crescents associated with a variety of marine and aquatic faunal remains. At site CA-SRI-512 on Santa Rosa Island, Paleocoastal peoples used such tools to capture geese, cormorants, and other birds, along with marine mammals and finfish. At Cardwell Bluffs on San Miguel Island, Paleocoastal peoples collected local chert cobbles, worked them into bifaces and projectile points, and discarded thousands of marine shells. With bifacial technologies similar to those seen in Western Pluvial Lakes Tradition assemblages of western North America, the sites provide evidence for seafaring and island colonization by Paleoindians with a diversified maritime economy.     

CO2-forced climate and vegetation instability during Late Paleozoic deglaciation

The late Paleozoic deglaciation is the vegetated Earth's only recorded icehouse-to-greenhouse transition, yet the climate dynamics remain enigmatic. By using the stable isotopic compositions of soil-formed minerals, fossil-plant matter, and shallow-water brachiopods, we estimated atmospheric partial pressure of carbon dioxide (pCO2) and tropical marine surface temperatures during this climate transition. Comparison to southern Gondwanan glacial records documents covariance between inferred shifts in pCO2, temperature, and ice volume consistent with greenhouse gas forcing of climate. Major restructuring of paleotropical flora in western Euramerica occurred in step with climate and pCO2 shifts, illustrating the biotic impact associated with past CO2-forced turnover to a permanent ice-free world.     

Contact activity of synthetic pyrethroids against adult grass grub,Costelytra zealandica (white)

The field life for contact activity of cypermethrin and permethrin, applied to pasture, was similar for all of five application rates between 0.25 and 1.5 kg ha^?1. Laboratory bioassays with grass grub beetles, Costelytra zealandica (White), showed that the insecticides lost their activity after about 4–9 days on pasture. Microencapsulation significantly increased the active field life of permethrin.     

American mink control on inland rivers in southern England: An experimental test of a model strategy

Invasive species are an important driver of global biodiversity loss. Under international legislation, the UK has an obligation to eradicate or to control the alien, invasive American mink. Using a large-scale field experiment, we tested the effectiveness of a specified mink removal strategy, identified through earlier modelling work, in reducing the relative abundance of mink. We found that mink removal could be effective in reducing mink populations with four months or less of trapping per year, over only 2-3 years, but that for small sites (c. 20 km) a flexible, reactive approach, coupled with continual monitoring for mink presence is necessary. Survival of reintroduced water voles at four sub-sites within our mink removal sites suggest that the reactive mink removal strategy adopted in this study was sufficient for water vole protection. We discuss the use of an adaptive management approach in local mink management, and consider the wider implications of our results for invasive species control on mainlands.     

Molecular cloning,purification and immunogenicity of recombinant Brucella abortus 544 malate dehydrogenase protein

The Brucella mdh gene was successfully cloned and expressed in E. coli. The purified recombinant malate dehydrogenase protein (rMDH) was reactive to Brucella-positive bovine serum in the early stage, but not reactive in the middle or late stage, and was reactive to Brucella-positive mouse serum in the late stage, but not in the early or middle stage of infection. In addition, rMDH did not react with Brucella-negative bovine or mouse sera. These results suggest that rMDH has the potential for use as a specific antigen in serological diagnosis for early detection of bovine brucellosis.     

Land use influences soil fungal community composition across central Victoria,south-eastern Australia

Current theory expects that fungi, on the one hand, are spatially ubiquitous but, on the other, are more susceptible than bacteria to disturbance such as land use change due to dispersal limitations. This study examined the relative importance of location and land use effects in determining soil fungal community composition in south-eastern Australia. We use terminal restriction fragment length polymorphism (T-RFLP; primer pair ITS1-F–ITS4) and multivariate statistical methods (NMDS ordinations, ANOSIM tests) to compare relative similarities of soil fungal communities from nine sites encompassing three locations (ca 50–200 km apart) and four land uses (native eucalypt forest, Pinus radiata plantation, Eucalyptus globulus plantation, and unimproved pasture). Location effects were generally weak (e.g. ANOSIM test statistic R ≤ 0.49) and were, in part, attributed to minor differences in soil texture. By contrast, we found clear and consistent evidence of land use effects on soil fungal community composition (R ≤ 0.95). That is, soils from sites of the same land use grouped together in NMDS ordinations of fungal composition despite geographic separations of up to ca 175 km (native eucalypt forests) and 215 km (P. radiata plantations). In addition, different land uses from the same location were clearly separate in NMDS ordinations, despite, in one case, being just 180 m apart and having similar land use histories (i.e. P. radiata versus E. globulus plantation both established on pasture in the previous decade). Given negligible management of all sites beyond the early establishment phase, we attribute much of the land use effects to changes in dominant plant species based on consistent evidence elsewhere of strong specificity in pine and eucalypt mycorrhizal associations. In addition, weak to moderate correlations between soil fungal community composition and soil chemical variables (e.g. Spearman rank correlation coefficients for individual variables of 0.08–0.32), indicated a minor contributing role of vegetation-mediated changes in litter and soil chemistry. Our data provide evidence of considerable plasticity in soil fungal community composition over time spans as short as 6–11 years. This suggests that – at least within geographic zones characterised by more-or-less contiguous forest cover – soil fungal community composition depends most on availability of suitable habitat because dispersal propagules are readily available for colonisation after land use change.