Relationship between nitrogen fixation and numbers of cyanobionts and heterocysts in fifteen Azolla strains

The relationship between nitrogen fixation and the numbers of cyanobionts and heterocysts in the mature leaves of fifteen Azolla strains from five species was examined. The nitrogenase (acetylene reduction) activity per leaf and the numbers of cyanobionts and heterocysts in the mature region varied depending on the Azolla strains. The numbers of cyanobionts and heterocysts, particularly the number of heterocysts, were closely correlated with the nitrogenase activity per leaf. However, the nitrogenase activity per leaf was not correlated with the nitrogenase activity per heterocyst. The results indicate that the variation in the nitrogenase activity of the leaves among Azolla strains mainly resulted from the variation in the number of heterocysts and not from the variation in the nitrogenase activity per heterocyst.     

Purification and sensitivity of Clostridium chauvoei hemolysin to various erythrocytes

Using ammonium sulphate fractionation, the Clostridium chauvoei hemolysin was purified by cation exchange chromatography and sephacryl S-100 gel filtration. The molecular mass of the hemolysin, determined by SDS-PAGE was found to be approximately 27kDa. The activity of the hemolysin was determined in erythrocytes of various animals, with sensitivities observed in the order of cow, sheep, chicken, rabbit, rat, mouse, dog and horse. Temperature affected the sensitivity of erythrocytes to C. chauvoei hemolysin. These results may reflect distinct characteristics of the hemolytic activity of C. chauvoei hemolysin and that the hemolysin may be pore-forming.     

Simulation of Pastoral Management in Mongolia: An Integrated System Dynamics Model

High grazing density has given rise to concerns about grassland degradation in periurban areas in Mongolia. Moreover, whether livestock can increase without harming the vegetation in these areas in Mongolia and what types of policy measures should be implemented is not documented. As such, this study develops an integrated simulation model of grassland biomass, animal growth, and livestock management for a forest-steppe area in northern Mongolia and conducts a simulation on long-term changes. The simulations show that, under current conditions, the number of animals will continue to increase, while the grassland biomass will decrease. Cooperative grassland management would lead to an increase in grassland biomass and higher incomes for herders. Furthermore, herders’ population changes would have a significant impact on animal density adjustments, while the effects of conventional economic measures, such as a tax on animals, would be limited if all other conditions remain constant. Consequently, the synergistic effects of herder population changes and cooperative management can contribute toward maintaining the herders’ income while preserving the grassland ecosystem.     

Relationship between Clostridium septicum alpha-toxin activity and binding to erythrocyte membranes

The activity of Clostridium septicum alpha-toxin was determined in erythrocytes of various animals, with sensitivities observed in the order of mouse, rat, canine, equine, rabbit, chicken, bovine, swine and ovine. Temperature and protease treatment affected the sensitivity of erythrocytes to alpha-toxin. Proteinase K treatment decreased the sensitivity of murine, canine, equine and bovine erythrocytes, but ovine erythrocytes did not change the sensitivity to alpha-toxin activity. On the other hand, the activity of alpha-toxin on swine erythrocytes increased after treatment with proteinase K, trypsin, chymotrypsin or lysyl endopeptidase. Toxin overlay assay showed that alpha-toxin bound to erythrocyte membrane proteins with a molecular mass of 30 to 45-kDa in mouse, equine, bovine, swine and chicken, whereas in rat erythrocyte membranes the toxin reacted with 100-kDa protein. The treatment of murine and swine erythrocyte membranes with phosphatidylinositol-specific phospholipase C resulted in liberation of the toxin-binding protein from the individual membranes in a native state. These results show that alpha-toxin associates with specific erythrocyte membrane proteins in any animal species, and are subsets of glycosylphosphatidylinositol-anchored proteins in various animal species. These results may reflect distinct characteristics of the hemolytic activity of alpha-toxin in response to various erythrocytes.     

Temporal and regional variability of cumulative ecological risks of pesticides in Japanese river waters for 1990–2010

We quantitatively evaluated the cumulative ecological risks from multiple pesticides used in paddy fields in Japan. Moreover, we visualized the temporal and regional variability of those risks for 1990–2010. Considering the region-specific parameters of environmental conditions, region-specific predicted environmental concentrations were estimated at 350 river-flow monitoring sites in Japan. Then the multi-substance potentially affected fraction (msPAF) was calculated as a risk index of multiple pesticides by using the computation tool NIAES-CERAP. The median msPAF values for insecticides and herbicides decreased by 92.4% and 53.1%, respectively, from 1990 to 2010. This substantial reduction in ecological risk was attributed to the development of low-risk pesticides by manufacturers, the efforts of farmers in risk reduction, and tighter regulation by the Japanese government. In particular, the substantial reduction of the ecological risk from insecticides was largely due to the decrease in the use of organophosphorus insecticides.     

Rapid method for detecting resistance to a QoI fungicide in Plasmopara viticola populations

BACKGROUND: The increasing occurrence of Qo inhibitor (QoI)‐fungicide‐resistant Plasmopara viticola (Berk. & MA Curtis) Berl. & DeToni populations is becoming a serious problem in the control of grapevine downy mildew worldwide. RESULTS: The authors have developed a rapid method for detecting resistance to a QoI fungicide, azoxystrobin, in P. viticola populations using the nested PCR‐RFLP method. With this method, a glycine‐to‐alanine substitution was discovered at codon 143 in the cytochrome b gene of P. viticola populations found in Japan. CONCLUSION: It is proposed that the nested PCR‐RFLP method is a high‐speed, sensitive and reliable tool for detecting azoxystrobin‐resistant P. viticola populations. Copyright © 2009 Society of Chemical Industry     

浑善达克沙地牧户经营与草地变化的实证分析

本文以浑善达克沙地牧户调查数据为基础,在草地畜牧业可持续发展理论指导下,通过对牧户经营现状以及草地变化状况的实证分析,明确了牧户经营基本特点、经营收入支出构成与草地资源变化特征,并提出调整畜种结构,适当增加牛的饲养比重;科学管理,提高牲畜出栏率;加强牲畜改良,提高良种比率;完善草畜平衡制度,加强监督、执法力度等对策。     

Correction to: Spatial and seasonal variations of radiocesium concentrations in an algae-grazing annual fish,ayu Plecoglossus altivelis collected from Fukushima Prefecture in 2014

Fisheries Science - In the original publication the caption of Fig. 6a and 6b is incorrectly published.