Rodent model for long-term maintenance and development of the viable cysticerci of Taenia saginata asiatica

Although oncospheres of Taenia saginata asiatica can develop into cysticerci in immunodeficiency, immunosuppressed, and normal mice, no detailed information on the development features of these cysticerci from SCID mice is available. In the present study, the tumor-like cyst was found in the subcutaneous tissues of each of 10 SCID mice after 38-244 days inoculation with 39,000 oncospheres of T. s. asiatica. These cysts weighed 2.0-9.6 gm and were 1.5-4.3 cm in diameter. The number of cysticerci were collected from these cysts ranged from 125 to 1,794 and the cysticercus recovery rate from 0.3% to 4.6%. All cysticerci were viable with a diameter of 1-6 mm and 9 abnormal ones each with 2 evaginated protoscoleces were also found. The mean length and width of scolex, protoscolex, and bladder were 477 x 558, 756 x 727, and 1,586 x 1,615 microns, respectively. The diameters of suckers and rostellum were 220 microns and 70 microns, respectively. All cysticerci had two rows of rostellar hooks. These findings suggest that the SCID mouse model can be employed as a tool for long-term maintenance of the biological materials for advanced studies of immunodiagnosis, vaccine development, and evaluation of cestocidal drugs which would be most benefit for the good health of the livestocks.     

Genetic Diversity of Taenia asiatica from Thailand and Other Geographical Locations as Revealed by Cytochrome c Oxidase Subunit 1 Sequences

Twelve 924 bp cytochrome c oxidase subunit 1 (cox1) mitochondrial DNA sequences from Taenia asiatica isolates from Thailand were aligned and compared with multiple sequence isolates from Thailand and 6 other countries from the GenBank database. The genetic divergence of T. asiatica was also compared with Taenia saginata database sequences from 6 different countries in Asia, including Thailand, and 3 countries from other continents. The results showed that there were minor genetic variations within T. asiatica species, while high intraspecies variation was found in T. saginata. There were only 2 haplotypes and 1 polymorphic site found in T. asiatica, but 8 haplotypes and 9 polymorphic sites in T. saginata. Haplotype diversity was very low, 0.067, in T. asiatica and high, 0.700, in T. saginata. The very low genetic diversity suggested that T. asiatica may be at a risk due to the loss of potential adaptive alleles, resulting in reduced viability and decreased responses to environmental changes, which may endanger the species.     

青藏高原放牧地社会-经济-自然复合生态系统变迁

由于全球气候变化和人为活动的影响,我国放牧地社会-经济-自然复合生态系统发生了复杂、深刻且剧烈的变化。青藏高原放牧地复合生态系统面积约占全国此类生态系统总面积的三分之一。它对气候变化极度敏感,同时又是少数民族牧民的主要聚居区。因此,该生态系统具有生态、经济、政治、文化等多功能性,对维护边疆稳定和民族团结有重要意义。对建国以来该复合生态系统的水热条件、植被质量、土壤状况、大气氧含量等自然组分的变化进行了系统性综述与分析,并进一步探讨其自然及社会-经济成因。结果发现,草地制度变迁和生态恢复工程的实施在一定程度上扭转了生态恶化趋势,但草地退化并未得到全面解决,且全球气候变化可能进一步增加高原生态环境变化的不确定性。此外,未来还应就如何应对草原鼠害;如何权衡野生动物保护与家畜放牧的矛盾;如何平衡传统文化传承与牧业现代化需求间的潜在冲突;如何应对缺氧环境对高原人畜影响等生态系统管理议题进行深入研究,以推动人-草-畜和谐共生,实现牧区可持续高质量发展。     

Infection of Taenia asiatica in a Bai Person in Dali,China

We report here a human case of Taenia asiatica infection which was confirmed by genetic analyses in Dali, China. A patient was found to have symptoms of taeniasis with discharge of tapeworm proglottids. By sequencing of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene, we observed nucleotide sequence identity of 99% with T. asiatica and 96% with T. saginata. Using the cytochrome b (cytb) gene, 99% identity with T. asiatica and 96% identity with T. saginata were found. Our findings suggest that taeniasis of people in Dali, China may be mainly caused by T. asiatica.     

Characteristics of the Achnatherum splendens community along the Qinghai-Tibet Railway, China

The Achnatherum splendens community is an important type of warm steppe vegetation which plays a very important role in environmental protection in the area along the Qinghai-Tibet Railway. In order to under-stand its dynamic features, the characteristics of the A. splendens community, such as spatial distribution pattern, species richness and biomass, were examined near Haiyan County, Qinghai Province. Results showed that the A. splendens community consisted of two types of mosaic patches, the microaggregation dominated by A. splendens and the microaggregation dominated by Stipa sp. The number and size of the two patches showed an interesting distribution pattern. The A. splendens patch decreased with increasing distance away from the railway, while species diversity increased. The total coverage of A. splen-dens was significantly higher than that of Stipa sp. The number and size of patches may indicate the degradation of the A. splendens community, which could be acceler-ated by human activities. Based on the characteristics and status quo of the A. splendens community, we suggest that some measures be taken to control human activities and rodents to conserve the A. splendens community.     

Altitudinal Distribution of Ammonia-Oxidizing Archaea and Bacteria in Alpine Grassland Soils Along the South-Facing Slope of Nyqentangula Mountains,Central Tibetan Plateau

Nitrogen is a major limiting nutrient for the net primary production of terrestrial ecosystems, especially on sentinel alpine ecosystem. Ammonia oxidation is the first and rate-limiting step on nitrification process and is thus crucial to nitrogen cycle. To decipher climatic influence on ammonia oxidizers, their communities were characterized by qPCR and clone sequencing by targeting amoA genes (encoding the alpha subunit of ammonia mono-oxygenase) in soils from 7 sites over an 800 m elevation transect (4400–5200 m a.s.l.), based on “space-to-time substitution” strategy, on a steppe-meadow ecosystem located on the central Tibetan Plateau (TP). Archaeal amoA abundance outnumbered bacterial amoA abundance at lower altitude (<4800 m a.s.l.), but bacterial amoA abundance was greater in surface soils at higher altitude (≥4800 m a.s.l.). Archaeal amoA abundance decreased with altitude in surface soil, while its abundance stayed relatively stable and was mostly greater than bacterial amoA abundance in subsurface soils. Conversely, bacterial amoA abundance gradually increased with altitude at all three soil depths. Statistical analysis indicated that altitude-dependent factors, in particular pH and precipitation, had a profound effect on the abundance and community of ammonia-oxidizing bacteria, but only on the community composition of ammonia-oxidizing archaea along the altitudinal gradient. These findings imply that the shifts in the relative abundance and/or community structure of ammonia-oxidizing bacteria and archaea may result from the precipitation variation along the altitudinal gradient. Thus, we speculate that altitude-related factors (mainly precipitation variation combing changed pH), would play a vital role in affecting nitrification process on this alpine grassland ecosystem located at semi-arid area on TP.     

高寒草甸物种多样性对藏系牧羊放牧行为的影响

为探究草原植物物种多样性对家畜放牧行为的影响及其机制,在青藏高原高寒草甸开展藏系牧羊轮牧试验,调查植被物种多样性,观察藏系牧羊采食速率、觅食速率和采食时间,并计算藏系牧羊日采食量。结果表明：两年间,植物物种丰富度与藏系牧羊采食速率呈显著正相关关系（P<0.05）;觅食速率、采食时间和日采食量对放牧率响应敏感（P<0.05）,呈夏秋增冬春减的趋势。植物Shannon-Wiener指数与藏系牧羊的采食时间显著负相关（P<0.05）;在暖季或8羊/hm²放牧率下植物Shannon-Wiener指数与藏系牧羊日采食量呈显著正相关（P<0.05）。Pilelou均匀度指数与藏系牧羊采食速率和采食时间显著负相关（P<0.05）;在暖季或8羊/hm²放牧率下Pilelou均匀度指数与藏系牧羊日采食量呈显著负相关（P<0.05）。植物物种丰富度对藏系牧羊放牧行为贡献较大,且放牧藏系牧羊的采食速率和采食时间比觅食速率和日采食量对植物物种丰富度响应更敏感,以用植物物种丰富度为自变量可以更好预测藏系牧羊放牧行为。放牧管理通过影响植被物种多样性从而进一步影响了藏系牧羊放牧行为。放牧行为不仅是评价草地营养价值和家畜生产力的关键指标,也是草地健康管理的基础。因此,明确草原植物物种多样性-藏系牧羊放牧行为的互作机制有助于更好的提高藏系牧羊地生产力,维护草原生态健康。     

中国青藏高原北部戈壁区种子植物物种组成及其区系特征

青藏高原北部戈壁区海拔变化幅度大,极端干旱、低温且大风,特殊环境条件导致该区种子植物区系组成有别于其他戈壁区。本文在野外调查的基础上,对该区种子植物组成与植物区系特征进行了分析。结果显示：（1）青藏高原北部戈壁区种子植物组成贫乏,调查中共记录种子植物17科50属69种,以灌木、半灌木及多年生草本为主;（2）该区含属、种数较多的科有：藜科、菊科、柽柳科、禾本科、豆科等,科内物种组成简单,优势物种主要有：红砂（Reaumuria songarica（Pall.） Maxim.）、驼绒藜（Ceratoides latens（J.F.Gmel.） Reveal et Holmgren）、合头藜（Sympegma regelii Bunge）、沙拐枣（Calligonum mongolicum Turcz.）、膜果麻黄（Ephedra przewalskii Stapf）、松叶猪毛菜（Salsola laricifolia Turcz.ex Litv.）等;（3）种子植物区系地理成分较为复杂,其中科的分布区类型以世界分布型占绝对优势,属的分布区类型以北温带分布及地中海区、西亚至中亚分布类型为重要成分;中国特有、戈壁区特有植物在植被组成中多为建群种或优势种;（4）与其他荒漠区相比,该区北温带分布及其变型,地中海区、西亚至中亚分布及其变型的比例达65%以上,显著高于黑戈壁地区、临近的库姆塔格沙漠及整个西北荒漠区。该区种子植物区系组成具有一定特殊性与过渡性特征。     

青藏高原阿里、那曲和海西地区土壤可培养放线菌的多样性

【目的】为了研究青藏高原北部地区土壤可培养放线菌的多样性,并比较不同选择性分离培养基对高原土壤放线菌的分离效果。【方法】使用9种分离培养基,并尝试添加藤黄微球菌发酵液,对采集自阿里、那曲和海西地区的14份土壤样品中的放线菌进行选择性分离。通过16S r RNA基因序列分析对分离菌株进行初步分类鉴定,并在不同分类水平上统计所分离得到的放线菌多样性。【结果】分离得到去重复后的放线菌255株,分布于放线菌门的8个目,14个科,23个属,包含94个可能的物种。其中至少25个物种可能为新种,分布于13个属。链霉菌属的菌株108株,可能的物种28个,是最主要的优势菌属。分离培养基中添加藤黄微球菌发酵液明显增加了放线菌分离菌株的数量和多样性,稀释的葡萄糖酵母麦芽汁培养基适合分离链霉菌,淀粉甘油脯氨酸培养基、丙酸钠酪蛋白培养基等则适合分离稀有放线菌。【结论】青藏高原北部土壤放线菌多样性非常丰富,并且存在较多的新颖放线菌类群;添加藤黄微球菌发酵液是提高放线菌分离效率的有效手段。     

A mini-review of advances in the study of the evolution of Perdix species

The Northern Eurasia origin hypothesis is one key point in the evolutionary model. This indicates that species riginated in Northern Eurasia. Perdix, belonging to Phasianidae of Galliformes, is a valuable type of wildfowl widely distributed Northern Eurasia and contains three species. This mini-review discusses the taxonomic status, phylogeny, and origin of Perdix. Morphological and molecular evidence suggest that the three species, P. hodgsoniae, P. dauuricae and P. perdix, form a monophyletic group and they should be classified as pheasant rather than quail. The current review also shows that results were affected by the methods selected for data analysis. A taxonomic category should contain as many species as possible, have a clear system history, remain evolutionarily stable, and lack adaptive radiation. Appropriate type, number and length of genes are important as molecular markers and out-group affects the bootstrap support value. P. hodgsoniae is located at the root of the phylogenetic tree and has the phenotype of ancestral Perdix. The genus Perdix may originate in the Qinghai-Tibet Plateau and expanded into high latitude areas, towards the northern plateau. This phylogenetic and evolutionary statement differs from the Eurasian origin hypothesis.