基于最大熵生态位模型的中华穿山甲潜在适宜生境预测

中华穿山甲（Manis pentadactyla）属于全球极度濒危物种,也是我国一级保护动物。对中华穿山甲的非法捕杀曾导致其种群数量锐减。但是,近年来相关研究报道较少,穿山甲分布状况不明,极大地制约了对该物种的有效保护。搜集了近年来国内中华穿山甲的救护记录和救护新闻,甄别出67个记录分布点,利用最大熵模型软件（MaxEnt）进行因子筛选,结果表明最冷季度降水量、人口密度、年降水量、坡度、坡向、海拔等6个环境变量是与中华穿山甲分布显著相关的影响因子。基于6个主导环境变量构建的MaxEnt模型AUC平均值为0.961±0.014,预测结果达到极好标准。刀切法（Jackknife）表明,其中最冷季度降水量、年降水量、人口密度和海拔是影响中华穿山甲分布的主要因素。中华穿山甲适宜生境（出现概率大于0.498）具有以下特点：最冷季度降水量141.22-439.46 mm,年降水量1471.67-2386.56 mm,人口密度≥390人/km²,海拔<316.98 m。该模型预测中华穿山甲在我国的潜在分布适宜区主要位于我国长江以南地区,总面积约为74.27×10⁴ km²,占国土面积的7.73%,主要集中在江西、广东、湖南和广西省,面积分别占该区域的97.58%,89.65%,76.90%和73.08%;其次是浙江、福建、台湾和安徽省。湖北、江苏、四川、云南、贵州等省份也有中华穿山甲的零星分布。湖北东南部、江苏南部、浙江西南部和福建西北部等与江西接壤的区域也是中华穿山甲的重要潜在分布适宜区。明确中华穿山甲的潜在分布适宜区,可为该物种的种群保护和栖息地管理提供科技支撑。     

烟青虫核型多角体病毒的复制和染病后血淋巴蛋白的变化

用烟青虫(Hiliothis assulta)核型多角体病毒感染5龄初烟青虫幼虫,以染病后24、48·,72、96/120小时分别测定了虫体血淋巴蛋白浓度的变化。幼虫染病后24小时血淋巴蛋白浓度要高于同期对照组,72小时后染病幼虫血淋巴蛋白浓度较对照急剧下降。在染病及对照血淋巴样品中电泳分析(PAGE)三种蛋白(普通蛋白、糖蛋白和脂蛋白)均可分别染出22条、3条和3条带。分析结果表明,在虫体正常生长代谢过程中发生变化的主要蛋白可能大多为糖脂复合蛋白,但病毒的侵染能抑制这些变化的产生。电镜观察染病毒后幼虫的中肠组织和气管上皮组织,发现中肠染病轻微,不形成多角体。气管上皮细胞感染情况表明其属于对NPV感染较为敏感的组织之一,并在虫体染病后的病毒二次感染上可能起着重要作用。     

Morphology of Coenophthalmus tridentatus first zoea (Crustacea: Portunidae: Polybiinae) hatched in the laboratory

The swimming crab Coenophthalmus tridentatus A. Milne Edwards,1879 (Decapoda, Portunidae) is an endemic species of the SouthwesternAtlantic, from southern Brazil to northern Patagonia (Argentina).Larvae of C. tridentatus from one female collected on beds ofoysters and mussels at 50 m depth in the Argentine continentalshelf (38°21'S, 57°38'W) were hatched in the laboratory.Zoea I morphology is described for the first time and comparedwith known zoeae of other portunid species.     

Effects of cigarette smoke condensate on proliferation and wound closure of bronchial epithelial cells in vitro: role of glutathione

Background

Increased airway epithelial proliferation is frequently observed in smokers. To elucidate the molecular mechanisms leading to these epithelial changes, we studied the effect of cigarette smoke condensate (CSC) on cell proliferation, wound closure and mitogen activated protein kinase (MAPK) activation. We also studied whether modulation of intracellular glutathione/thiol levels could attenuate CSC-induced cell proliferation.

Methods

Cells of the bronchial epithelial cell line NCI-H292 and subcultures of primary bronchial epithelial cells were used for the present study. The effect of CSC on epithelial proliferation was assessed using 5-bromo-2-deoxyuridine (BrdU) incorporation. Modulation of epithelial wound repair was studied by analysis of closure of 3 mm circular scrape wounds during 72 hours of culture. Wound closure was calculated from digital images obtained at 24 h intervals. Activation of mitogen-activated protein kinases was assessed by Western blotting using phospho-specific antibodies.

Results

At low concentrations CSC increased proliferation of NCI-H292 cells, whereas high concentrations were inhibitory as a result of cytotoxicity. Low concentrations of CSC also increased epithelial wound closure of both NCI-H292 and PBEC, whereas at high concentrations closure was inhibited. At low, mitogenic concentrations, CSC caused persistent activation of ERK1/2, a MAPK involved in cell proliferation. Inhibition of cell proliferation by high concentrations of CSC was associated with activation of the pro-apoptotic MAP kinases p38 and JNK. Modulation of intracellular glutathione (GSH)/thiol levels using N-acetyl-L-cysteine, GSH or buthionine sulphoximine (BSO), demonstrated that both the stimulatory and the inhibitory effects of CSC were regulated in part by intracellular GSH levels.

Conclusion

These results indicate that CSC may increase cell proliferation and wound closure dependent on the local concentration of cigarette smoke and the anti-oxidant status. These findings are consistent with increased epithelial proliferation in smokers, and may provide further insight in the development of lung cancer.     

Preliminary evaluation of non-native rainbow trout (Oncorhynchus mykiss) impact on the Cederberg ghost frog (Heleophryne depressa) in South Africa’s Cape Fold Ecoregion

We evaluated the impact of non-native rainbow trout Oncorhynchus mykiss on a population of endemic Cedarberg ghost frog Heleophryne depressa in the upper Krom River (Olifants-Doring River Catchment, Cape Fold Ecoregion). We compared H. depressa abundance (using kick-sampling and underwater video analysis) and environmental conditions between sites above and below a waterfall that marks the upper distribution limit of O. mykiss. Heleophryne depressa abundance was significantly greater above the waterfall than that below it, and, because there was no significant difference in measured environmental variables, O. mykiss presence is identified as the most likely explanation for the observed decrease in H. depressa abundance.     

Distribution and habitat preferences of two grapsid crab species in Mar Chiquita Lagoon (Province of Buenos Aires,Argentina)

Cyrtograpsus angulatus andChasmagnathus granulata (Grapsidae) are the two dominant decapod crustacean species in the outer parts of Mar Chiquita Lagoon, the southernmost in a series of coastal lagoons that occur along the temperate Atlantic coasts of South America. Distribution and habitat preferences (water and sediment type) in these crab species were studied in late spring. There is evidence of ontogenetic changes in habitat selection of both species. Recruitment ofC. angulatus takes place mainly in crevices of tube-building polychaete (Ficopomatus enigmaticus) “reefs” and, to a lesser extent, also in other protected microhabitats (under stones). In the latter, mostly somewhat larger juveniles were found, suggesting that these are used as a refuge for growing individuals. Adults are most frequently found on unprotected muddy and sandy beaches.C. angulatus was found in all parts of Mar Chiquita Lagoon, including freshwater, brackish, and marine habitats.C. granulata, in contrast, was restricted to the lower parts of the lagoon, where brackish water predominates and freshwater or marine conditions occur only exceptionally. It showed highest population density on “dry mud” flats and inSpartina densiflora grassland, where it can build stable burrows and where high contents of organic matter occur in the sediment. Such habitats are characterized by mixed populations of juveniles (including newly settled recruits) and adults, males and females (including a high percentage of ovigerous). Unstable “wet mud” as well as stony sand were found to be inhabited by chiefly adult populations, with only few ovigerous females. In “dry mud” flats, the proportion of males increased vertically with increasing level in the intertidal zone, showing a significantly increasing trend also in their average body size. These observations may be explained by higher resistance of males, in particular of large individuals, to desiccation, salinity, and temperature stress occurring in the upper intertidal. However, an opposite, or no such, tendency was found in the distribution of ovigerous and non-ovigerous females, respectively. With increasing distance from the water edge, salinity increased and pH decreased significantly inC. granulata burrows, whereas temperature showed no consistent tendency within the intertidal gradient. A highly significant linear relationship (r=−0.794; P<0.001) between salinity and pH in water from crab burrows is described. This regression line is significantly different from one that had been observed in water from the lagoon, indicating consistently lower pH values at any salinity level in burrow water. This is interpreted as a result of crab and/or microbial respiration.     

Distribution and conservation of mobile elements in the genus Drosophila

Essentially nothing is known of the origin, mode of transmission, and evolution of mobile elements within the genus Drosophila. To better understand the evolutionary history of these mobile elements, we examined the distribution and conservation of homologues to the P, I, gypsy, copia, and F elements in 34 Drosophila species from three subgenera. Probes specific for each element were prepared from D. melanogaster and hybridized to genomic DNA. Filters were washed under conditions of increasing stringency to estimate the similarity between D. melanogaster sequences and their homologues in other species. The I element homologues show the most limited distribution of all elements tested, being restricted to the melanogaster species group. The P elements are found in many members of the subgenus Sophophora but, with the notable exception of D. nasuta, are not found in the other two subgenera. Copia-, gypsy-, and F-element homologues are widespread in the genus, but their similarity to the D. melanogaster probe differs markedly between species. The distribution of copia and P elements and the conservation of the gypsy and P elements is inconsistent with a model that postulates a single ancient origin for each type of element followed by mating-dependent transmission. The data can be explained by horizontal transmission of mobile elements between reproductively isolated species.      

Temporal and spatial fluctuations of heavy metals in Opa Reservoir,Ile-Ife,Nigeria

The Opa Reservoir, established for water supply to the Obafemi Awolowo University community, over the years has received direct linkage to township drains as a result of the widening and dredging of its river channels. The current study aimed at documenting monthly heavy metal loads at its riverine, transition and lacustrine zones in 2012–2013. Most of the heavy metals, analysed using an atomic absorption spectrophotometer, occurred within wide ranges, with coefficients of variation ranging from 60% to 300%, although the differences in heavy metal loads between the different zones were statistically insignificant at both the surface and bottom levels. The overall order of dominance of the metals was Ni > Cu > Fe > Zn > Cd = Cr > Pb, with nickel concentration being very high throughout. Heavy metal total mean concentration was higher during the rainy season (1.889 mg l?1) than the dry season (1.503 mg l?1) irrespective of sampling sites, having highly significant seasonal differences (p < 0.001) in Ni, Cd, Fe and Cu concentrations. The mean concentrations of Zn (0.074 mg l?1), Fe (0.176 mg l?1), Cu (0.507 mg l?1) and Pb (0.004 mg l?1) were within the WHO acceptable limit. However, the recorded levels of toxic elements Cd (0.031 mg l?1) and Ni (0.905 mg l?1) pose potential health risk to water consumers.     

Trophic ecology and persistence of invasive silver carp Hypophthalmichthys molitrix in an oligotrophic South African impoundment

The alien invasive silver carp Hypophthalmichthys molitrix established a self-sustaining feral population in an oligotrophic impoundment, Flag Boshielo Dam, in South Africa. The ability of this population to persist in a dam with low algal biomass (median annual suspended chlorophyll a = 0.08 µg l^?1), and limited access to rivers considered large enough for successful spawning, has implications for their invasive potential in other systems. Stomach content and stable isotope analysis were used to assess the trophic ecology of H. molitrix, which was then compared with indigenous Mozambique tilapia Oreochromis mossambicus, on a seasonal basis during 2011. Hypophthalmichthys molitrix are generalist filter feeders, with a diet consisting primarily of sediment, vegetative detritus, dinoflagellates and diatoms. The dominance of sediments in their stomachs suggests occasional benthic scavenging. However, H. molitrix occupied a higher trophic level (TL = 2.8) than expected, suggesting that this population subsidised their diet with an unidentified dietary constituent, characterised by enriched nitrogen values. Although the stomach contents indicated dietary overlap between H. molitrix and O. mossambicus, stable isotopes revealed fine-scale resource partitioning, despite both species occupying the same trophic level. Nonetheless, the persistence of this feral H. molitrix population in an oligotrophic impoundment highlights their phenotypic plasticity.