南海海军部队特发性瘙痒症患者皮肤马拉色菌定植调查

目的研究南海海军部队特发性皮肤瘙痒症患者皮肤马拉色菌的检出以及菌种的构成,探讨马拉色菌与特发性瘙痒症之间的相关性。方法对采自56例特发性瘙痒症患者与50例健康者的鳞屑标本进行真菌学镜检及采用菜子油培养基培养,根据菌落形态和生理生化特点进行菌种鉴定。结果观察组与对照组镜检阳性率分别为74．10％和72．00％,X2=0．344,P〉0．05两者比较无统计学意义。而镜检马拉色菌孢子密度Ⅲ级以上（每10个高倍视野≥50个者）,观察组与对照组分别为74．70％和38．89％,X2=20．30,P〈0．01。两者统计学比较差异有显著性意义。观察组168份标本共分离出143株马拉色菌,阳性率85．12％。其中合轴马拉色菌97株（67．83％）,球形马拉色菌26株（18．18％）,糠秕马拉色菌19株（13．29％）,钝形马拉色菌1株（0．70％）。对照组分离出马拉色菌107株,阳性率71．33％;其中糠秕马拉色菌55株（51．40％）,合轴马拉色菌33株（30．84％）,球形马拉色菌14株（13．08％）,钝形马拉色菌5株（4．67％）。菌种检出率和菌种构成差异均有显著性（X2=2．99,P〈0．01和7。X2=51.16,P〈0．01）。结论南海海军部队特发性瘙痒症患者皮肤马拉色菌载量较正常人高,其优势菌是合轴马拉色菌。     

Identification and characterization of hydrophobic Escherichia coli virulence proteins by liquid chromatography-electrospray ionization mass spectrometry

Virulence of enterotoxicogenic Escherichia coli is mediated by rodlike, rigid, highly hydrophobic proteins designated fimbriae or colonization factors (CFs). More than 20 different colonization factors have been described so far using predominantly immunological and genetic methods. To characterize these hydrophobic proteins by liquid chromatography-mass spectrometry (LC-MS), different methodologies were explored. A novel LC-MS method was developed using hexafluoroisopropanol to maintain the hydrophobic proteins in solution. In addition, these proteins were digested with cyanogen bromide and peptide mapping by LC-MS was established. This technique was particularly useful in identification of closely related CFs. Both LC-MS and peptide mapping methodologies were found to be useful in characterizing highly hydrophobic CFs of E. coli. To search for molecular weights of mature proteins in the National Center for Biotechnology Information (NCBI) database, a new feature was developed and its applicability tested. The identification of a class of pathogenic virulence proteins, either intact or digested, is possible with molecular weight database searching.     

从新疆哈萨克族2型糖尿病患者粪便中分离的气单胞菌对小鼠的作用研究

目的 从新疆哈萨克族2型糖尿病患者粪便中分离培养气单胞菌,并回接到小鼠体内,检测其对小鼠血糖、血脂等2型糖尿病相关中间表型的作用。方法 （1）收集新鲜哈萨克族２型糖尿病患者的粪便样本,用气单胞菌专属培养基进行分离培养,微量生化反应管进行初步鉴定;提取所得菌株的DNA,使用气单胞菌属引物对此DNA进行特异性扩增,结合全自动细菌鉴定仪对菌株进行鉴定;（2）将气单胞菌菌液回接小鼠,采用羰花青素染料（CM-Dil）标记法对菌定植力情况进行检测。（3）检测气单胞菌菌液对小鼠体重、随机血糖（GLU）、空腹血糖（FBG）、总胆固醇（TC）和甘油三酯（TG）的作用,进行葡萄糖耐量（OGTT）、胰岛素耐量（ITT）试验。结果 （1）所得到的菌株经全自动细菌鉴定仪确定为气单胞菌;（2）从小鼠粪便中分离培养后的细菌能检测到荧光标记;（3）与正常饮食组小鼠相比,气单胞菌稀释液、原液、浓缩液组小鼠体重均升高;气单胞菌原液组小鼠GLU升高。小鼠FBG、TC和TG在各组间差异均无统计学意义;气单胞菌菌液组小鼠口服葡萄糖耐量试验血糖曲线下面积增加;气单胞菌原液、浓缩液组小鼠胰岛素耐量试验血糖曲线下面积增加。结论 （1）从新疆哈萨克族2型糖尿病患者粪便中分离培养得到气单胞菌;（2）从糖尿病患者粪便中分离的气单胞菌可定植于小鼠体内,并使小鼠的体重增加,GLU升高,给予气单胞菌稀释液、菌原液、菌浓缩液后第8周,小鼠出现糖耐量受损,胰岛素敏感性下降。     

Temporal lags in observed and dark diversity in the Anthropocene

Understanding biodiversity changes in the Anthropocene (e.g. due to climate and land‐use change) is an urgent ecological issue. This important task is challenging because global change effects and species responses are dependent on the spatial scales considered. Furthermore, responses are often not immediate. However, both scale and time delay issues can be tackled when, at each study site, we consider dynamics in both observed and dark diversity. Dark diversity includes those species in the region that can potentially establish and thrive in the local sites’ conditions but are currently locally absent. Effectively, dark diversity connects biodiversity at the study site to the regional scales and defines the site‐specific species pool (observed and dark diversity together). With dark diversity, it is possible to decompose species gains and losses into two space‐related components: one associated with local dynamics (species moving from observed to dark diversity and vice versa) and another related to gains and losses of site‐specific species pool (species moving to and from the pool after regional immigration, regional extinction or change in local ecological conditions). Extinction debt and immigration credit are useful to understand dynamics in observed diversity, but delays might happen in species pool changes as well. In this opinion piece we suggest that considering both observed and dark diversity and their temporal dynamics provides a deeper understanding of biodiversity changes. Considering both observed and dark diversity creates opportunities to improve conservation by allowing to identify species that are likely to go regionally extinct as well as foreseeing which of the species that newly arrive to the region are more likely to colonize local sites. Finally, by considering temporal lags and species gains and losses in observed and dark diversity, we combine phenomena at both spatial and temporal scales, providing a novel tool to examine biodiversity change in the Anthropocene.     

Establishment of Beauveria bassiana as a fungal endophyte in potato plants and its virulence against potato tuber moth,Phthorimaea operculella (Lepidoptera: Gelechiidae)

The potato tuber moth, Phthorimaea operculella, is the most damaging potato pest in the world and is difficult to control as the larvae are internal feeders in the foliage and tubers. Entomopathogenic fungi that colonize plants as endophytes have lethal and sublethal pathological effects on insect pests. We show that Beauveria bassiana colonizes the aerial parts of potato plants endophytically after inoculation through soil drenching. Endophytic B. bassiana persisted in potato foliage for more than 50 days postinoculation. Bioassays indicated that foliage of B. bassiana-inoculated potato plants were pathogenic against larvae of P. operculella. Sublethal experiments indicated that B. bassiana negatively affected the growth, development, and reproduction of P. operculella. Development experiments showed that the weight of P. operculella pupae reared on B. bassiana-colonized potato plants (4.25 mg) was significantly less than that of those reared on uninoculated control plants (8.89 mg). Compared with newly eclosed larvae fed on control plants, those fed on B. bassiana-inoculated plants had significantly lower survivorship, with only 17.8% developing to the adult stage. Oviposition of P. operculella females reared on B. bassiana endophytically colonized plants was significantly lower (35 eggs/female) than of those reared on uninoculated plants (115 eggs/female). This study demonstrates that endophytic B. bassiana can be a potential biological control agent for the control and management of P. operculella. Comparing pupal weights of P. operculella reared on potato plants inoculated with the B. bassiana strain GZGY-1-3 and on untreated control plants, pupae from the control plants were significantly heavier than those from treated plants.     

Genetic architecture influences when and how hybridization contributes to colonization

The role of genetic architecture in adaptation to novel environments has received considerable attention when the source of adaptive variation is de novo mutation. Relatively less is known when the source of adaptive variation is inter- or intraspecific hybridization. We model hybridization between divergent source populations and subsequent colonization of an unoccupied novel environment using individual-based simulations to understand the influence of genetic architecture on the timing of colonization and the mode of adaptation. We find that two distinct categories of genetic architecture facilitate rapid colonization but that they do so in qualitatively different ways. For few and/or tightly linked loci, the mode of adaptation is via the recovery of adaptive parental genotypes. With many unlinked loci, the mode of adaptation is via the generation of novel hybrid genotypes. The first category results in the shortest colonization lag phases across the widest range of parameter space, but further adaptation is mutation limited. The second category takes longer and is more sensitive to genetic variance and dispersal rate, but can facilitate adaptation to environmental conditions that exceed the tolerance of parental populations. These findings have implications for understanding the origins of biological invasions and the success of hybrid populations.     

湿地植物的丛枝菌根（AM）

随着对湿地重要性认识的增加,湿地植物的丛枝菌根（arbuscular mycorrhiza,AM）结构研究受到了关注。研究表明,AM结构在多种湿地类型和湿地植被类型中存在,但AM形成受植被生长地水文状况的影响;从湿地植物上的AM真菌种类看,球囊霉属（Glomus）是湿地环境的常有属。同陆生植物相比,有关湿地植物AM结构的研究尽管已取得了一些进展,但还有很大差距,尤其在我国还几乎处于空白状态。鉴此,从形成AM的湿地植被类型、湿地环境中的AM真菌种类、AM对湿地植物生长的影响,以及影响湿地植物AM形成的因素等方面进行了详细阐述,并对今后的研究方向做了展望,以期为我国开展湿地植物AM结构研究提供参考。     

Suppression of ectomycorrhizae on canopy tree seedlings in Rhododendron maximum L. (Ericaceae) thickets in the southern Appalachians

 Thickets of Rhododendron maximum (Ericaceae) (Rm) in the southern Appalachians severely limit regeneration of hardwood and coniferous seedlings. Experimental blocks were established in and out of Rm thickets in a mature, mixed hardwood/conifer forest in Macon County, N.C. Litter and organic layer substrates were removed, composited and redistributed among plots within the blocks (except for control plots). Seedlings of northern red oak (Quercus rubra) and eastern hemlock (Tsuga canadensis) were planted in the plots and harvested at the end of the first and second growing seasons. Litter manipulation had no effect on total mycorrhizal colonization, but the distribution of Cenococcum geophilum mycorrhizae was altered. After the first year, percent mycorrhizal colonization of hemlocks not in Rm thickets (62%) was at least three times higher than in Rm thickets (19%), and the ramification index (no. of mycorrhizae cm^–1) had increased by more than a factor of four (2.83 versus 0.61). In addition, colonization of 1-year-old hemlocks by C. geophilum was significantly higher within blocks with (10.4%) than without (4.6%) Rm. Differences in mycorrhizal colonization, ramification indices and colonization by C. geophilum were absent or less pronounced on 2-year-old hemlocks and 1- and 2-year-old oak seedlings. The biomasses of first year oak roots and shoots and second year shoots were 50% less in Rm thickets. Biomasses of first year hemlock roots and second year shoots were also reduced. Mycorrhizal parameters were correlated with some growth parameters only for hemlock seedlings, but did not explain most of the variation observed. Accepted: 12 February 1999