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We hypothesized that host antiviral genes induced by type I interferons might affect the natural course of severe acute respiratory syndrome (SARS). We analyzed single nucleotide polymorphisms (SNPs) of 2',5'-oligoadenylate synthetase 1 (OAS-1), myxovirus resistance-A (MxA), and double-stranded RNA-dependent protein kinase in 44 Vietnamese SARS patients with 103 controls. The G-allele of non-synonymous A/G SNP in exon 3 of OAS-1 gene showed association with SARS (p=0.0090). The G-allele in exon 3 of OAS-1 and the one in exon 6 were in strong linkage disequilibrium and both of them were associated with SARS infection. The GG genotype and G-allele of G/T SNP at position -88 in the MxA gene promoter were found more frequently in hypoxemic group than in non-hypoxemic group of SARS (p=0.0195). Our findings suggest that polymorphisms of two IFN-inducible genes OAS-1 and MxA might affect susceptibility to the disease and progression of SARS at each level.  相似文献
我国中越边境地区有毒植物资源的调查研究   总被引:6,自引:0,他引:6  
对中越边境地区有毒植物资源进行了调查研究,列出了主要的有毒植物的名单及其有毒部位、学名、中文名、科名、习性和毒性,并在此基础上对该地区有毒植物资源进行了总体评价。此外,还提出了因地制宜开发利用该地区丰富的有毒植物资源的建议。  相似文献
兜兰属宽瓣亚属(广义)的被充研究   总被引:5,自引:0,他引:5  
对新种小囊兜兰Paphiopedilum globulosum与新变种扁球兜兰P.micranthum var.oblatum作了描述与绘图。两者均为采自云南东南部的栽培植物,与硬叶兜兰P.micranthum近似。但小囊兜兰具有宽得多的叶(宽2.8-3.4cm),先端多少呈钩状、宽1.1-1.2cm的辱瓣,以及与唇瓣囊口几乎同样大小的退化雄蕊,而扁球兜兰则叶宽2.2-3cm,唇瓣扁球形,囊深不超过1cm,可区别于硬叶兜兰。上述种类均属于宽瓣亚属(广义)。该亚属有16个种产中国、越南或两地共有。本文提供了分种检索表。  相似文献
Mosquitoes (Diptera: Culicidae) of the Anopheles (Cellia) Myzomyia Series are important malaria vectors in Africa, India and Southeast Asia. Among 10 named species of Myzomyia known from the Oriental Region, seven form the An. minimus group. Even for expert taxonomists, the adults of these species remain difficult to identify morphologically. For technical staff of malaria control programmes, confusion may extend to misidentification of species that are not formally within the minimus group. For identification of specimens from Indochina (Cambodia, Laos, Vietnam), we describe a multiplex polymerase chain reaction (PCR) assay, based on rDNA internal transcribed spacer 2 (ITS2) sequences, that employs a cocktail of primers to identify An. minimus Theobald sibling species A and C (sensu; Green et al., 1990) and three other species in the An. minimus group (An. aconitus Dönitz, An. pampanai Büttiker & Beales, An. varuna Iyengar), as well as An. jeyporiensis James, also belonging to the Myzomyia Series. As the test is DNA-based, it can be applied to all life stages of these mosquitoes for ecological investigations and vector incrimination studies. This PCR assay is simpler, quicker, cheaper and more readily interpreted than previous assays.  相似文献
Dengue haemorrhagic fever emerged in the 1950s and has become a major public health concern in most Asian countries. In Vietnam, little is known about the intraspecific variation of the vector and its consequences on vectorial capacity. Here we report the use of microsatellite markers to differentiate Aedes aegypti populations in Ho Chi Minh City, a typical, overcrowded Asian city. Six microsatellite loci, with 5-14 alleles per locus, were scored in 20 mosquito samples collected in 1998 in Ho Chi Minh City. We found substantial differentiation among Ae. aegypti populations from the outskirts, whereas populations from the centre of the city showed less differentiation. These results are consistent with the hypothesis that populations of Ae. aegypti in central Ho Chi Minh City are panmictic because there are abundant larval breeding sites and an abundance of humans for adults to feed upon. In contrast, populations on the outskirts become differentiated largely through the processes of genetic drift because larval breeding sites are not as abundant. These findings implicate human activities associated with urbanization, as factors shaping the genetic structure of Ae. aegypti populations.  相似文献
A survey was conducted on the species composition, richness and abundance of Papilionoidea (excluding Lycaenidae) butterfly fauna in habitats with various degrees of disturbance and altitudes in tropical forests at Tam Dao National Park, northern Vietnam in 2001. The transect method was used to collect data in the survey. Six transects representing different habitat types at two sites, one site located at a low elevation of 200–250 m a.s.l., and the other located at a high elevation of 950–1000 m a.s.l., were chosen: three transects for each site, with a length of 500 m for each transect. A total of 3594 individuals of 127 species in 240 sets of data were recorded from various habitats. The differences in butterfly composition, species richness, abundance and diversity in different habitat types and altitudes were analyzed. The results showed significant differences of butterfly diversity among the different habitat types and between the low and high altitude sites. The butterfly diversity, species richness and species abundance in the low elevation habitats were higher than in the high elevation habitats. The highest diversity of butterflies occurred in the mixed habitats of agriculture, scrub and clearing lands of high disturbance. However, butterflies most important for conservation are associated with undisturbed or moderately disturbed forests only.  相似文献
Samples of the dengue vector mosquito Aedes aegypti (L.) (Diptera: Culicidae) were collected from 13 localities between 1995 and 1998. Two laboratory strains, Bora (French Polynesia) and AEAE, were both susceptible to DDT and permethrin; all other strains, except Larentuka (Indonesia) and Bouaké (Ivory Coast), contained individual fourth-instar larvae resistant to permethrin. Ten strains were subjected to a range of biochemical assays. Many strains had elevated carboxylesterase activity compared to the Bora strain; this was particularly high in the Indonesian strains Salatiga and Semarang, and in the Guyane strain (Cayenne). Monooxygenase levels were increased in the Salatiga and Paea (Polynesia) strains, and reduced in the two Thai strains (Mae Kaza, Mae Kud) and the Larentuka strain. Glutathione S-transferase activity was elevated in the Guyane strain. All other enzyme profiles were similar to the susceptible strain. The presence of both DDT and pyrethroid resistance in the Semarang, Belem (Brazil) and Long Hoa (Vietnam) strains suggested the presence of a knock-down resistant (kdr)-type resistance mechanism. Part of the S6 hydrophobic segment of domain II of the voltage-gated sodium channel gene was obtained by RT-PCR and sequenced from several insects from all 13 field strains. Four novel mutations were identified. Three strains contained identical amino acid substitutions at two positions, two strains shared a different substitution, and one strain was homozygous for a fourth alteration. The leucine to phenylalanine substitution that confers nerve insensitivity to pyrethroids in a range of other resistant insects was absent. Direct neurophysiological assays on individual larvae from three strains with these mutations demonstrated reduced nerve sensitivity to permethrin or lambda cyhalothrin inhibition compared to the susceptible strains.  相似文献
越南铁线莲属一新种   总被引:3,自引:0,他引:3       下载免费PDF全文
本文描述的产于越南的毛茛科Ranunculaceae铁线莲属Clematis一新种C. hagiangensis N. T. Do是欧亚大陆第一个具单性花的种, 在花构造方面与单性铁线莲组单性铁线莲亚组sect. Aspidanthera Spach subsect. Dioicae (Prantl) W. T. Wang的种类近缘, 但叶均为单叶, 萼片呈卵形或宽卵形而不同。在单性铁线莲亚组的种, 叶通常为复叶, 只在C. dimorphophylla W. T. Wang和C. variifolia W. T. Wang同时为单叶和复叶, 此外萼片呈长圆形、倒披针形或狭卵形。  相似文献
越南蕨类植物的新记载(1)   总被引:3,自引:0,他引:3  
报道了越南6种新记载的蕨类植物,包括分布和简短讨论Christensenia assamica (Griff.) Ching,Arthropteris repens (Brack.)C.Chr.,Cyrtomium hemionitis H.Christ,Cyrtogonellum sichouensis S.K.Wu & Musuta,Dryopteris conjugata Ching,and Lepisorus sinensis (H.Christ) Ching.  相似文献
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