Seasonal dietary niche contraction in coexisting Neotropical frugivorous bats (Stenodermatinae)

Tropical dry forests are characterized by punctuated seasonal precipitation patterns that drive primary production and the availability of fruits, seeds, flowers, and insects throughout the year. In environments in which the quantity and quality of food resources varies seasonally, consumers should adjust their foraging behavior to maximize energy intake while minimizing overlap with competitors during periods of low food availability. Here, we investigated how the diets of frugivorous bats in tropical dry forests of NW Mexico varied in response to seasonal availability and how this affected dietary overlap of morphologically similar species. We performed stable isotope analyses to understand temporal and interspecific patterns of overall isotopic niche breadth, trophic position, and niche overlap in the diet of six frugivorous species of closely related New World leaf-nosed bats (family Phyllostomidae, subfamily Stenodermatinae). We estimated seasonal changes in resource abundance in two complementary ways: (a) vegetative phenology based on long-term remote sensing data and (b) observational data on food availability from previously published insect and plant fruiting surveys. In all species, there was a consistent pattern of reduced isotopic niche breadth during periods of low food availability. However, patterns of niche overlap varied between morphologically similar species. Overall, results from our study and others suggest that seasonal food availability likely determines overall dietary niche breadth in Phyllostomidae and that despite morphological specialization, it is likely that other mechanisms, such as opportunistic foraging and spatiotemporal niche segregation, may play a role in maintaining coexistence rather than simply dietary displacement.     

Preparation and Properties of Human Kappa-casein-like Fraction

A κ-casein-like fraction was prepared from human whole casein by gel filtration with Sephadex G-150 and Biogel A-150 m. The fraction was calcium-insensitive and its solution became turbid by rennin. In polyacrylamide gel electrophoretic (PAE) analysis, the fraction gave 11~12 bands after reduction with 2-mercaptoethanol. It appeared to exist as a disulfide- bound complex of many components. The occurrence of human para-IC-caseins from the fraction after rennin treatment was confirmed by PAE. When the reduced, alkylated human κ-casein-like fraction was chromatographed by DEAE-cellulose, several fractions were obtained. After rennin treatment, they formed either a para-SCM-κ-casein band moving toward the cathode on PAE pattern or the one which moved toward the anode. These results suggest that two para-κ-caseins were formed from human whole casein or human κ-casein-like fraction by the action of rennin.     

蝉棒束孢菌子实体对大鼠肾小管上皮细胞的影响

对蝉棒束孢菌子实体（0.75g/kg）重复灌胃SD雄性大鼠90d及恢复28d的早期肾损伤生物标记物肾损伤分子-1（KIM-1）和中性粒细胞明胶酶相关载脂蛋白（NGAL）进行测定,评估蝉棒束孢菌子实体对肾小管上皮细胞的影响;研究不同剂量蝉棒束孢菌子实体（0.25g/kg、0.5g/kg、1.0g/kg）对肾小管上皮细胞增殖和增生能力的影响。给药30、60、90d及恢复28d时,SD大鼠血清中KIM-1浓度与对照组相比均无显著差异（P>0.05）,给药30d、60d时,SD大鼠血清中NGAL浓度与对照组相比均无显著差异（P>0.05）,给药90d及恢复28d时,SD大鼠血清中NGAL浓度低于对照组（P<0.05）,且给药90d组与对照组相比有显著性差异（P<0.01）;免疫组化检测增殖细胞核抗原法（PCNA）及四甲基偶氮唑盐微量酶反应比色法（MTT）表明：与对照组相比,蝉棒束孢菌子实体能使肾小管上皮细胞增生能力增强,未导致肾小管上皮细胞凋亡。     

巴氏蘑菇子实体不同发育阶段的转录组分析

为探讨巴氏蘑菇子实体不同发育阶段基因的表达情况,本研究对巴氏蘑菇子实体不同发育时期（原基、采收期和开伞期）进行转录组测序,以本实验室已获得的巴氏蘑菇JA菌株的不育单孢菌株JA-15036基因组为参考基因组研究原基与采收期及开伞期样本间差异表达基因,并对差异表达基因进行了GO功能和Pathway富集分析。GO功能分析结果显示,差异表达基因主要富集在跨膜转运、碳水化合物代谢途径和膜组分,它们协同调控为子实体生长发育提供稳定的内环境。KEGG富集分析结果表明,原基期上调的差异表达基因主要富集在核糖体蛋白和DNA复制,表明原基期细胞代谢旺盛,其中核糖体蛋白基因上调为后期蛋白质合成提供重要场所;采收期和开伞期子实体时期差异表达基因主要富集在碳水化合物代谢、脂肪酸降解和氨基酸代谢等途径,为巴氏蘑菇子实体的生长发育与成熟提供营养与能量。     

深挖垦复对锥栗重要农艺性状及土壤理化性质的影响

为探索锥栗林地高效的土壤管理方式,提升我国锥栗栽培管理技术水平,进而提高其产量、品质以及经济效益。该研究采用全垦和环垦两种方式对锥栗林地进行连续4年的深挖垦复,通过测定垦复前后土壤理化性质变化以及锥栗树体生长、叶片表型和生理特征、结果性状、产量及品质等重要农艺性状,统计数据并进行对比分析。结果表明:(1)深挖垦复对锥栗林地土壤理化性质改善效果显著,两种垦复方式土壤容重较垦复前降低31.21%及以上(0～30 cm处),土壤含水率、土壤孔隙度、有机质含量以及各种大量元素含量较垦复前和对照均有不同程度的增加,土壤肥力及其保水保肥能力显著增强。(2)环垦区土壤有机质含量、有效磷含量以及交换性镁含量高于全垦区,其土壤有机质含量较垦复前增加40.59%,远高于全垦增加幅度(17.76%),从土壤保肥能力的角度来看,环垦效果优于全垦。(3)土壤肥力的提升增强了其对锥栗叶片的供肥能力,使得叶片含水率、叶绿素含量以及各种矿质元素含量显著增加,从而提升其光合作用能力。(4)深挖垦复对锥栗树体生长、结实能力、产量及品质同样具有显著的提升效果,其中全垦和环垦区单位面积产量分别是对照的1.75倍和1.33倍,且栗苞总重、单果质量、出籽率、可溶性糖含量以及磷、钾元素含量显著高于对照,而空苞率显著低于对照。综上,深挖垦复是改良林地土壤和提高锥栗生产力的有效举措。     

Maxent modeling for predicting the potential distribution of Sanghuang,an important group of medicinal fungi in China

The ability to identify the spatial distribution of economically important fungal species is crucial for understanding the environmental factors that affect them and for conservation management. A potentially valuable approach for this is maximum entropy (Maxent) spatial distribution modeling, which was applied here to map the potential distribution of three “Sanghuang” mushrooms in China, which include Phellinus baumii, Phellinus igniarius and Phellinus vaninii. Nineteen WorldClim bioclimatic variables, with corresponding altitude data, and 89 spatially well-dispersed species occurrence records were used in the modeling. The relative importance of the environmental variables was evaluated by Jackknife tests in the modeling analysis. The maximum entropy models obtained have high Area Under Receiver Operating Characteristic Curve (AUC) values: 0.956, 0.967 and 0.960, for P. baumii, P. igniarius and P. vaninii, respectively. The bioclimatic variable that most strongly affected distributions of P. baumii and P. vaninii was precipitation in the warmest quarter, while the mean temperature in the warmest quarter affected the distribution of P. igniarius most strongly. Overall, these models could provide valuable help in searching for the target species in areas where it is hitherto unknown, and be the reference of conservation measures for these medicinal fungal species.