中国典型冻土区土壤可培养细菌多样性

[目的]对比分析中国典型高纬度冻土区和高海拔冻土区土壤可培养细菌的多样性.[方法]采用NM、TSA 、R2A 3种培养基分离培养不同冻土区土壤可培养细菌,用通用引物扩增分离的细菌16S rRNA基因,根据系统发育分析进行鉴定.[结果]从6个样品中得到冻土土壤可培养细菌的菌落数量为4.70×103 -2.57×105 cfu/g(土壤干重),根据不同的菌落形态分离出144株可培养细菌.纯培养物的16S rRNA基因部分序列分析表明:我国高纬度冻土区土壤样品中的细菌分别属于Firmicutes分支(59.52％)、Gammaproteobacteria 分支(38.10％)、Betaproteobacteria分支(2.38％),其中假单胞菌属(Pseudomonas)、芽胞杆菌属(Bacillus)、类芽胞杆菌属(Paenibacillus)的菌株为该区域的三大优势菌群.我国高海拔冻土区土壤样品中分离细菌属于Gammaproteobacteria分支(89.22％)、Firmicutes分支(8.82％)和Bacteroidetes分支(1.96％)o优势菌群为假单胞菌属( Pseudomonas).[结论]我国高纬度冻土区和高海拔冻土区土壤具有较高的可培养细菌多样性;不同类型冻土区土壤可培养细菌群落组成不同.本文研究结果将为我国冻土区土壤细菌资源研究与利用提供理论依据.     

栀子粗提物对抑郁模型小鼠行为学及海马神经发生的影响

目的观察栀子粗提物对慢性轻度应激模型小鼠行为学及海马神经发生的影响。方法采用10种不同应激源实施对小鼠连续10周刺激,从第3周开始口服给予栀子粗提物3个剂量治疗8周后,测定各组小鼠行为学改变,并采用NeuN和BrdU免疫组化观察海马区神经细胞的增殖情况。结果栀子粗提物高剂量组蔗糖饮水量明显增加（P〈0.05）,强迫游泳不动时间明显缩短（P〈0.05）;NeuN阳性表达升高（P〈0.01）,BrdU阳性细胞的面数密度亦显著增加（P〈0.05）。结论栀子粗提物对抑郁模型小鼠行为有明显改善作用,并能显著促进海马区神经元发生,提示栀子粗提物具有良好的抗抑郁作用。     

Africa goes Europe: The complete phylogeography of the marbled white butterfly species complex Melanargia galathea/M. lachesis (Lepidoptera: Satyridae)

Climatic oscillations influence the distribution of species in time. Thermophilic species survived the ice ages in refugia around the Mediterranean. Northern Africa is one of the possibly important refugia. In this study we test the genetic differentiation between northern African and European populations, using the marbled white butterfly species complex, Melanargia galathea/M. lachesis, as a model. We studied 18 allozyme loci in 876 individuals from 23 populations representing a major part of Europe (northern Spain to Romania) and the western part of northern Africa (Atlas Mountains). The African populations resemble the European ones in allelic richness; their genetic diversity is higher than in Europe. Cluster analysis discriminated five European genetic groups: M. lachesis, a western European lineage, and three eastern European lineages. However, the African samples did not form a separate cluster within this phenogram, but clustered randomly within the Balkan/southeastern European groups. The genetic differentiation among the African populations (F_ST 8.8%) was higher than that within any of the European lineages (F_ST 2.6–5.5%). The high genetic diversity and the relatively strong differentiation of the four African populations sampled in a comparatively limited area of the Atlas Mountains indicate that the most probable origin of M. galathea is northern Africa, with its sibling species, M. lachesis, evolving in parallel in Iberia. Most probably, M. galathea colonised Europe first during the Eem interglacial, some 130 ky ago. Since M. lachesis must have existed on the Iberian peninsula during that period already, M. galathea should have reached Europe via Italy. The genetic differentiation to distinct groups in Europe most probably evolved during the following Würm glacial period.     

Impacts of dust on plant health,survivorship and plant communities in semi‐arid environments

There is a general perception that dust accumulation on plant surfaces causes negative impacts to plants. Consequently, it is common for environmental regulatory agencies to apply vegetation monitoring requirements to oil, gas and mining developments. We use two independent, medium‐term monitoring studies in semi‐arid Australia to examine this relationship at two scales: plant health and survivorship of a threatened subspecies (Tetratheca paynterae paynterae: Elaeocarpaceae) at Windarling Range between 2003 and 2014; and changes in plant health and floristic composition on Barrow Island between 2009 and 2014. Accumulation of dust decreased rapidly with distance from source. At Windarling Range, even at the site with the highest dust load, there was no significant impact on Tetratheca paynterae paynterae compared with the less dusty sites for 10 years. Similarly, there was no significant effect between distance from the source of dust and floristic composition on Barrow Island for 5 years. The probability of plants transitioning to a lower health condition between one year and the next did not appear to be related to dust load. This is further supported by comparing the same site before and after paving the road (removal of dust source), which showed no clear trends. Trends in plant health are likely to be driven more by the variability of cumulative rainfall in the preceding 5 months than dust load. The observed temporal variation in the mean dust load may also be related to variation in rainfall. In conclusion, in these case studies from semi‐arid Australia, we find no evidence to support the perception that, under the observed climatic condition and dust deposition rates up to 20 or 77 g m^?2 per month at Windarling Range and Barrow Island, respectively, dust accumulation on plants causes negative impacts.     

武陵山区蕨类植物研究

武陵山区蕨类植物资源丰富,现知有644种(包括变种),分属116属, 46科;蕨类区系属热带-亚热带山地类型;属的地理成份有12种类型,与日本、印度-马来西亚有密切关系;武陵山区蕨类区系属我国西南区系,与华中华东区关系密切,华南、华北区次之;蕨类垂直分布分四带。     

指掌骨骨折合并软组织损伤的微型锁定钢板皮外固定应用效果及对关节活动度的影响

摘要 目的：探讨指掌骨骨折合并软组织损伤的微型锁定钢板皮外固定的应用效果及对关节活动度的影响。方法：选取我院2015年7月到2020年7月共收治的80例指掌骨骨折合并软组织损伤的患者作为研究对象,将其随机分为观察组与对照组,各40例。对照组应用克氏针、微型螺钉、肌腱缝线或拉力螺钉进行内固定,观察组在对照组基础上联合应用微型锁定钢板皮外固定,并针对患者合并软组织损伤情况应用石膏外固定。对比两组患者的骨折愈合时间、围术期指标、Jamar握力、TAM、DASH评分、术后不良反应情况以及生活质量。结果：观察组手术时间高于对照组,骨折愈合时间和住院时间较对照组低（P＜0.05）;观察组患者的DASH评分明显低于对照组,TAM与Jamar握力明显高于对照组（P＜0.05）;观察组术后并发症发生率较对照组低（P＜0.05）;术后1个月两组患者生活质量评分均升高,高于对照组（P＜0.05）。结论：对指掌骨骨折合并软组织损伤的患者在常规克氏针内固定的基础上,应用微型锁定钢板皮外固定,再进行石膏固定,手术步骤、手术时间虽增加,但更有利于患者术后骨折愈合,减少术后并发症的发生,减少住院时间,促进患者出院后关节功能恢复,提高生活质量,值得临床应用推广。     

Estimating Fundamental Host Range: a Host-Specificity Study of a Potential Biocontrol Agent for Prosopis Species (Leguminosae)

One approach to predicting non-target attack by potential biological control agents is to first describe their fundamental host ranges and then to predict how it will be expressed under postrelease field conditions. In this paper, we illustrate how the fundamental host range can be estimated experimentally by excluding possible limiting factors such as time-dependent effects. The example we use is a host-specificity study of a leaf-tying moth (Gelechiidae: Evippe sp. #1) which was being assessed for the biological control of mesquite (Leguminosae: Prosopis spp.) in Australia. Females oviposited all eggs on plants, mostly into cracks and fissures. First instar larvae leaf-mined and subsequent instars leaf-tied. Oviposition was not host-specific in cage trials, although ten times more eggs were laid on Prosopis than on non-targets. The fundamental host range for initiation of larval feeding was restricted to Prosopis and Leucaena leucocephala which both belong to the same tribe, and the fundamental host range for complete larval development was restricted to Prosopis . We predict that if released in Australia Evippe sp. #1 will only attack Prosopis spp., although low levels of 'indiscriminate' oviposition might occur on other taxa, and might result in initiation of feeding on L. leucocephala .     

Space-time diversification of Androcymbium Willd. (Colchicaceae) in western South Africa

 We examined patterns of cpDNA RFLP variability using 21 restriction endonucleases in 21 populations of Androcymbium that represent 12 endemic species distributed in the winter rainfall areas of South Africa to explore the diversification of the genus in its area of maximum species diversity. Our results are supportive of a diversification landscape characterized by continued opportunistic short-range invasion, naturalization, and rapid speciation, in which the selective action of the different environments where Androcymbium species occur determined their colonization success and subsequent short-range geographic expansion. The historical presence of fire, the constraint imposed by the low concentration of nutrients throughout southwestern South Africa and the different reproductive capabilities of Androcymbium species have also likely stimulated species' diversification. Our divergence time estimates bolster the view that speciation of South African Androcymbium initiated in the late Eocene, intensified in the Oligocene and proceeded more sporadically during the Miocene. These chronological estimates also substantiate the previous hypothesis that most lineages of Androcymbium in South Africa are much more ancient than their North African relatives, whose diversification began in the late Miocene-early Pliocene. Received July 25, 2001 Accepted December 6, 2001