Seasonal changes in the histochemical properties of the olfactory epithelium and vomeronasal organ in the Japanese striped snake, Elaphe quadrivirgata

Seasonal changes in the histochemical properties of the vomeronasal and olfactory epithelia of the Japanese striped snake were examined in four seasons, viz. the reproductive, pre-hibernating, hibernating and post-hibernating seasons. In the vomeronasal and olfactory supporting cells, secretory granules were much more abundant in the hibernating season than in the other seasons. In the vomeronasal and olfactory receptor cells, the lipofuscin granules were much fewer in the post-hibernating season than in the other seasons. In histochemical studies with 21 lectins, several lectins stained the vomeronasal and olfactory epithelia (receptor cells, supporting cells and free border) more weakly in the hibernating season than in the reproductive season. However, all lectins stained both epithelia in the hibernating season after sialic acid removal in a similar manner as in the reproductive season after sialic acid removal. These lectin histochemical studies indicate that sialic acid residues in the vomeronasal and olfactory epithelia are more numerous in the hibernating season than in the reproductive season. The results suggest that during hibernation, the vomeronasal and olfactory receptor cells possibly undergo rapid cell turnover, and that during this time, the vomeronasal and olfactory epithelia are securely protected from pathogens by an innate immune defence system.     

Cytogenetical and molecularbiological studies on a bovine XY female.

A bovine XY female in Holstein-Friesian heifer, which appeared as female with uterus and ovaries but did not show the estrus until 23 months old after the birth, was cytogenetically and molecularbiologically examined. As results of chromosome analysis, leucocyte and fibroblasts from skin, spleen and kidney examined had only metaphase plates with 60, XY. From these results and the clinical characteristics, this case was clearly diagnosed as a pure XY female. It was ascertained that the two genes, ZFY and AMG gene which located on the short arm of the Y chromosome (Yp) were detected in normal bulls and a XY female, but were not detected in normal cow, mother cow and half-sib heifer by Southern blotting.     

Correction to: Dispersion and degradation of environmental DNA from caged fish in a marine environment

Fisheries Science - In the original publication the text in right column of page 330, the sequences of primers were incorrectly published as.     

Diversity of interaction types and ecological community stability

Ecological theory predicts that a complex community formed by a number of species is inherently unstable, guiding ecologists to identify what maintains species diversity in nature. Earlier studies often assumed a community with only one interaction type, either an antagonistic, competitive, or mutualistic interaction, leaving open the question of what the diversity of interaction types contributes to the community maintenance. We show theoretically that the multiple interaction types might hold the key to understanding community dynamics. A moderate mixture of antagonistic and mutualistic interactions can stabilize population dynamics. Furthermore, increasing complexity leads to increased stability in a "hybrid" community. We hypothesize that the diversity of species and interaction types may be the essential element of biodiversity that maintains ecological communities.     

Foraging adaptation and the relationship between food-web complexity and stability

Ecological theory suggests that complex food webs should not persist because of their inherent instability. "Real" ecosystems often support a large number of interacting species. A mathematical model shows that fluctuating short-term selection on trophic links, arising from a consumer's adaptive food choice, is a key to the long-term stability of complex communities. Without adaptive foragers, food-web complexity destabilizes community composition; whereas in their presence, complexity may enhance community persistence through facilitation of dynamical food-web reconstruction that buffers environmental fluctuations. The model predicts a linkage pattern consistent with field observations.     

A geostatistical approach to spatial density distributions of sika deer (Cervus nippon)

Sika deer (Cervus nippon) cause serious damage to trees in Japanese forests. Browsing, bark stripping, and tree abrasion with antlers account for 50% of total wildlife damage over the past decade. The extent of forest damage depends on deer population density. We determined the spatial distribution of sika deer population density on Mt. Hiko (Fukuoka Prefecture, southwestern Japan). We also investigated changes in population density distribution over time. Determinants of population density were examined, with particular emphasis on the hunting cull. Deer densities in 1999 and 2004 were estimated by fecal pellet counts at 86 sites. We used kriging, a geostatistical technique that is a component of geographic information systems, to interpolate site-specific point data over large areas of landscape. Mapping procedures showed that high-density (≥30.0 deer km^?2) and low-density sections of landscape (≤10.0 deer km^?2) decreased in areal extent between 1999 and 2004. Contractions of high-density sections were attributable to intensive hunting. In low-density landscape sections, reduced hunting pressure allowed increased persistence of adult animals whose high fecundity led to population growth and higher deer densities. Landscape tracts with medium deer densities (10.0–30.0 deer km^?2) expanded, adding further difficulties to the task of wildlife management. Given the scale of the problems caused by deer, it is clear that reliable estimates of population size across space and time are essential components of the wildlife manager’s toolbox.     

Contextualizing farmers’ attitudes towards genetically modified crops

Analyses of the role of technological development in agriculture are central to an understanding of social change in agri-food systems. The objective of this paper is to contribute to the formation of a broader perspective of how farmers are positioning themselves with respect to controversial agricultural technologies through an empirical analysis of Washington State farmers’ willingness or unwillingness to try Genetically Modified Organisms (GMOs) technology on their farms. The use of this type of biotechnology in farming has been criticized for its potential harmful effects on natural environments and socio-cultural systems, while proponents highlight the possibilities for increasing production with minimal use of other inputs. An analysis of the extent of farmers’ expressed willingness to use GMOs provides an opportunity to better understand how their diverse thoughts about controversial agricultural technologies are shaped not only by their own experiences but also by social context. The present study does this by analyzing data from a farm survey conducted on a random sample of farmers from across Washington State. The results show that the production practices farmers utilize and the market strategies they employ may be at least as useful as farmers’ socio-economic characteristics in explaining what types of farmers appear to be more or less interested in potentially using this technology. Furthermore, the relationship between level of formal education and willingness to use GMOs is not straightforward. It may hide differences between farmers with respect to where and how they received their formal education as well as the type(s) of knowledge they gained. It is argued that future research should recognize the diversity that exists in farmers’ interests vis-á-vis particular technologies and should also explore how these interests are shaped by farmers’ past and present social networks and life experiences. Kazumi Kondoh is a PhD candidate in the Department of Sociology at Washington State University. Her research interests include environmental policies, science and technology, and sustainable agriculture. Raymond Jussaume is an Professor and Chair, Community and Rural Sociology at Washington State University. His primary areas of interest are sociology of agriculture, development sociology, and political sociology.     

The forest vegetation and its differentiation under disturbance in a temperate mountain, China

Composition and structure of the main forest types, as well as the species changes under disturbance, were described as the representation of the forest vegetation in the north slope of Changbai mountain, northeast China. There were 3 forest zones from 600 m to 2,000 m asl, (1) broad-leaved-conifer mixed forest zone, 600–1,100 m asl, dominated byPinus koraiensis, Tilia amurensis, Acer mono, Ulmus japonica, (2) coniferous forest zone, 1,100–1,700 m asl, dominated byPicea jezoensis var.komarovii, P. koraiensis, Abies nephrolepis, and (3)Betula ermanii forest zone, 1,700–2,000 m asl, dominated byBetula ermanii, except for the east slope which was occupied byLarix olgensis. The evergreen component increased with elevation up to the upper limit of the coniferous forest zone (1,700 m), but disappeared in theB. ermanii zone. Species richness was significantly related to elevation. Towards higher elevation, the lapse rate of species-number was 1.6 species per 100 m, and it was only one species near the timberline. Species richness was reduced sharply under intensive disturbance, such as clear cutting, windfalletc. The species diversity was very low in the early stage of succession, and high in the later.     

Requirement of DNase II for definitive erythropoiesis in the mouse fetal liver

Mature erythrocytes in mammals have no nuclei, although they differentiate from nucleated precursor cells. The mechanism by which enucleation occurs is not well understood. Here we show that deoxyribonuclease II (DNase II) is indispensable for definitive erythropoiesis in mouse fetal liver. No live DNase II-null mice were born, owing to severe anemia. When mutant fetal liver cells were transferred into lethally irradiated wild-type mice, mature red blood cells were generated from the mutant cells, suggesting that DNase II functions in a non-cell-autonomous manner. Histochemical analyses indicated that the critical cellular sources of DNase II are macrophages present at the site of definitive erythropoiesis in the fetal liver. Thus, DNase II in macrophages appears to be responsible for destroying the nuclear DNA expelled from erythroid precursor cells.