巴松措原生动物群落结构季节及垂直分布

为揭示我国西藏高原湖泊原生动物群落结构特征及垂直分布格局,于2017年11月及2018年5月和9月,在巴松措中心分7层设置采样点,利用25号浮游生物网采集原生动物。采用活体观察和固定染色相结合的方法,共鉴定到原生动物195种(其中春季86种,夏季93种,秋季80种),隶属于2门11纲24目43科59属。其中以肉鞭门种类较丰富,砂壳类纤毛虫占优势。垂直分布的物种组成和群落结构复杂表现为：表层>中层>底层,物种多样性、丰富度和优势度指数表现为：表层>中层>底层,均匀度指数大多数为1;季节分布的物种组成和群落结构群复杂程度表现为：夏季>春季>秋季,物种多样性、丰富度指数表现为：夏季>秋季>春季,优势度指数表现为：夏季>秋季>春季,均匀度指数表现为：秋季>春季>夏季;优势物种和群落结构都会随水深的增加而减少。总体呈现出物种多样性较低、均匀度较高,具有明显的时空异质性。     

脂肪间充质干细胞来源外泌体的功能

外泌体是细胞外膜质纳米囊泡,将蛋白质、核酸(DNA和RNA)转运到靶细胞中,介导局部和系统的细胞间通信,从而改变受体细胞的行为.这些小泡在许多生物功能中发挥重要作用,如脂肪合成、免疫调节、神经再生和肿瘤调节等.脂肪间充质干细胞目前被认为是细胞治疗和再生医学领域中一种功能丰富的工具,可产生和分泌多种外泌体,继承细胞的多种...     

Isolation and characterization of novel microsatellite loci for the short‐beaked common dolphin (Delphinus delphis) and cross‐amplification in other cetacean species

Seven tetranucleotide and three dinucleotide microsatellite loci were isolated from the short‐beaked common dolphin (Delphinus delphis). Number of alleles and observed heterozygosity ranged from three to twelve (mean 8.4) and from 0.087 to 0.978 (mean 0.741), respectively. All loci were tested in four other odontocete species and showed polymorphisms in most locus–species combinations. This panel of nuclear markers will be useful for the investigation of population ecology and social interactions in common dolphins and other cetacean species.     

ENVIRONMENTAL CONDITIONS, GROWTH AND PRODUCTION OF ANADARA SENILIS (LINNAEUS, 1758) IN A SENEGAL LAGOON

Two populations of Anadara senilis were sampled periodicallyin a lagoon of Senegal. Spatfall occurs in summer during therainy season. Population density decreases from about 50, 000.m^–2,two months after spatfall, down to 6, 750 one year later and750 after 28 months. The average growth, measured on the surfaceof the shell, following the umbo rim axis is 0.8 mm per month.The main reduction in growth rate occurs in winter and endsby the deposition of a growth ring. A second growth reductiontakes place during the rainy season and sometimes ends by aweak growth ring. The microgrowth increments are conspicuousand widest during spring equinox. They are not directly relatedto the tidal cycle, but it was impossible to determine if theyhave a tidal or a daily periodicity. (Received 11 February 1990; accepted 16 July 1993)     

The Longevity of Thermoactinomycete Endospores in Natural Substrates

Occupational debris from beneath the Roman fort Vindolanda, and lake sediments cored from Seamere in East Anglia were examined for the presence of viable Thermoactinomyces endospores. Up to 10⁴ viable endospores/g dry wt were recovered from the occupational debris at Vindolanda deposited between 1850 to 1890 years ago. Highest numbers were found in layers of bracken and straw litter sandwiched between clay floors within a military building. Associated artefacts and writing tablets have been used to date the various layers. Pollen analyses on core samples from Seamere revealed one region containing a declining percentage of tree pollen and the appearance of cereal and associated weed pollens suggesting the presence of a primitive agricultural community on the shores of the lake. Samples from this section of the core, deposited ca . 1950 to 2750 years ago, contained viable thermoactinomycete endospores. These studies confirm the extreme longevity of Thermoactinomycete endospores and suggest that these organisms may be usefully employed in future archaeological and palaeoecological studies.