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1.
Fanged frogs,now called Limnonectes kuhlii,from Borneo are remotely related to true Javanese L.kuhlii.For future taxonomy of Bornean fanged frogs,we fi x the nomenclatural status of two existing names,Rana conspicillata Günther,1872 and Rana paradoxa Mocquard,1890.Morphological comparison of the type-series revealed heterospecif ic relationships of the two species.For R.conspicillata,we designate BMNH 1947.2.29.20 as the lectotype,and for R.paradoxa,we also designate MNHN 1889.222 as the lectotype and propose a replacement name Limnonectes mocquardi,in order to stabilize their nomenclature.  相似文献   

2.
从线粒体基因探讨中国大头蛙群的分类及其属内地位   总被引:6,自引:0,他引:6  
Partial sequences of the mitochondrial 12S rRNA and 16S rRNA gene were determined for 8 populations of three species of Chinese Limnonectes, and aligned with the published sequences of Limnonectes from other parts of the world. When Nanorana parker, Paa boulengeri, Fejervarya limnocharis and Hoplobatrachus rugulosus was used as outgroup taxa (Accession Nos. AY158705, AY313685, AF206111, AF206491, AY322311). The sequences of the 12S rRNA and 16S rRNA genes totaled 950 nueleotide positions with gaps including 510 variable sites. We reconstructed phylogenetie trees using Clustal X 1.8, Mega 2.1 and PHYLIP 3.5e software, and using the maximum parsimony and maximum likelihood methods, respectively. Our analyses suggest that these fanged frogs from China are another monophyletie group in addition to the four monophyletie groups identified by previous studies. The Chinese Limnonectes were grouped into three elades (BCL 55% ). The first elade contains one species (BCL 100% ), from a population of Limnoneetes fragilis from Hainan Province. The second contains four individuals (BCL 100% ), i. e. two populations of Limnonectes kuhlii from Yunnan Province. The third contains one species (BCL 100% ), i. e. five populations of Limnonectes fujianensis from Fujian Province and 1 from Taiwan Province. The resulted phylogenetie trees indicate L. fragilis is basal to L. kuhlii L. fujianensis 。  相似文献   

3.
The matrilineal genealogy of the genus Paramesotriton is hypothesized based on DNA sequences from mitochondrial NADH subunit two (ND2) and its flanking tRNAs (tRN^Arp and a partial tRNA^Ala). The genealogy identifies a highly divergent, unnamed lineage from Qixiling Nature Reserve, Jiangxi, China and places it as the sister taxon of P. chinensis. The newly discovered population differs from other congeners by several features of external morphology including having large clusters of dark brown conical warts on the dorsum of the head, lateral surface of the body and dorsolateral ridges. Its intermittent dorsal vertebral ridge is the same color as other parts of the dorsum and tail narrows gradually from the base to the tip. Further, the new population differs from all congeners by an uncorrected P-distance of more than 9.38% in ND2. Consequently, we describe the new species of Asian warty newt (Salamandridae) as Paramesotriton qixilingensis sp. nov.  相似文献   

4.
Biology of the aphid Therioaphis maculata was studied on alfalfa (Medicago sativa L.), including four resistant (Mesa-Sirsa, CUF101, Baker and Lahontan) and two susceptible (ARC and Caliverde) alfalfa cultivars, and one of the most cropped Brazilian cultivars, Crioula. Under controlled conditions, antibiosis (i.e., reduced longevity, fecundity and increased mortality of the aphid) was observed mainly on the resistant alfalfa cultivars, except on Lahontan. Crioula seemed to be tolerant to aphids. Present data support geographic limitation usage of cultivars, and we suggest Baker and Mesa-Sirsa as sources of antibiosis, and provide biological information of a tropical T. maculata biotype on alfalfa.  相似文献   

5.
Hox and ParaHox genes constitute two families of developmental regulators that pattern the Anterior-Posterior body axis in all bilaterians.The members of these two groups of genes are usually arranged in genomic clusters and work in a coordinated fashion,both in space and in time. While the mechanistic aspects of their action are relatively well known,it is still unclear how these systems evolved. For instance,we still need a proper model of how the Hox and ParaHox clusters were assembled over time.This problem is due to the shortage of information on gene complements for many taxa (mainly basal metazoans) and the lack of a consensus phylogenetic model of animal relationships to which we can relate our new findings.Recently, several studies have shown that the Acoelomorpha most probably represent the first offshoot of the Bilateria. This finding has prompted us,and others, to study the Hox and ParaHox complements in these animals,as well as their activity during development.In this review,we analyze how the current knowledge of Hox and ParaHox genes in the Acoelomorpha is shaping our view of bilaterian evolution.  相似文献   

6.
7.
We have developed a sensitive and rapid lateral-flow immunoassay (LFIA) for WSSV, using colloidal gold as an indicator. The fusion protein, VP (19 28), was expressed in E. coli, purified and used to prepare polyclonal antibodies. The purified anti-VP (19 28) IgG were conjugated with colloidal gold. Unconjugated anti-VP (19 28) IgG and goat anti-rabbit IgG were immobilized on nitrocellulose membranes. After assembly, three groups (5 individual animals in each group) of shrimp samples were tested which included healthy, moribund and dead shrimps. For each group, three different tissues (body juices, gills and hepatopancreas) were tested at the same time. In parallel, all the samples were also analyzed using PCR for comparison. Out of 45 samples tested, 30 were detected as positive while 15 were classified as negative. The results of LFIA correlate with those obtained by the PCR analysis, indicating that these two detection methods have the same efficacy in the limited number of samples tested in this preliminary study.  相似文献   

8.
To investigate genetic mechanisms of high altitude adaptations of native mammals on the Tibetan Plateau, we compared mitochondrial sequences of the endangered Pantholops hodgsonii with its lowland distant relatives Ovis ames and Capra hircus, as well as other mammals. The complete mitochondrial genome of P. hodgsonii (16,498 bp) revealed a similar gene order as of other mammals. Because of tandem duplications, the control region of P. hodgsonii mitochondrial genome is shorter than those of O. ames and C. hircus, but longer than those of Bos species. Phylogenetic analysis based on alignments of the entire cytochrome b genes suggested that P. hodgsonii is more closely related to O. ames and C. hircus, rather than to species of the Antilopinae subfamily. The estimated divergence time between P. hodgsonii and O. ames is about 2.25 million years ago. Eutther analysis on natural selection indicated that the COXI (cytochrome c oxidase subunit I) gene was under positive selection in P. hodgsonii and Bos grunniens. Considering the same climates and environments shared by these two mammalian species, we proposed that the mitochondrial COXI gene is probably relevant for these native mammals to adapt the high altitude environment unique to the Tibetan Plateau.  相似文献   

9.
The hot-spring snakes,Thermophis, were previously known only from the Tibet Autonomous Region and Western Sichuan, China. During the past two years, three adult hot-spring snakes (2 females, 1 male) were sampled in Shangri-La, northern Yunnan, China, thus expanding their known distribution region towards the southeast. This site is the southeastern-most corner of the Tibetan Plateau and the southernmost tip of the Hengduan Mountains (Mts.). Phylogenetic analysis of mitochondrial (mt) and nuclear (n) DNA segments suggested that the three specimens belong to the genus ofThermophis. Morphologically, the new species is more similar toT. zhaoermii. However, it is distinguished fromT.zhaoermiiin the number of maxillary teeth (15), distance between the two eyes/head width, rostral width/height, mental width/height, in one character limited to female: head width/length, and in four characters restricted to male: occurrence of the reduction from 10 to 8 (8 to 6, 6 to 4) scales in each dorsal row on the tail. There are differences in morphology, genetics (mtDNA, nDNA), and geography between the putative new species andT.zhaoermii,the new species meets our proposed eclectic and feasible "four-differences" rule.  相似文献   

10.
11.
As an organophosphorus compound that frequently detected in water samples,triphenyl phosphate(TPhP)has been showed to have multiple toxicological effects on aquatic species.However,no attention has been paid to its potential impact on non-model amphibian species.Here,tadpoles of the Zhenhai brown frog(Rana zhenhaiensis)were exposed to different concentrations of TPh P(0,0.02 and 0.1 mg/L)throughout the developmental period to assess physiological and meta bolic impacts of TPh P exposure on amphibian larvae.After 30-day TPh P exposure,the developmental stage of tadpoles from the high-concentration treatment appeared to be more advanced than that from the other two treatments,but other measured traits(including body size,tail length and liver weight)did not differ among treatments.Metabolite profiles in tadpole livers based on liquid chromatographymass spectrometry(LC-MS)revealed a distinct metabolic disorder in exposed animals.Specifically,significant changes in various hepatic amino acids(such as glutamine,glutamate,valine and leucine)were observed.Overall,our results indicated that chronic TPhP exposure potentially caused developmental and hepatic physiological changes in R.zhenhaiensis tadpoles,although its impact on tadpole growth appeared to be minor.  相似文献   

12.
Grass species display a wide array of inflorescences ranging from highly branched compound/panicle inflorescences to unbranched spike inflorescences. The unbranched spike is a characteristic feature of the species of tribe Triticeae, including economically important crops,such as wheat and barley. In this review, we describe two important developmental genetic mechanisms regulating spike inflorescence architecture in barley and wheat.These include genetic regulation of(i) row-type pathway specific to Hordeum species and(ii) unbranched spike development in barley and wheat. For a comparative understanding, we describe the branched inflorescence phenotypes of rice and maize along with unbranched Triticeae inflorescences. In the end, we propose a simplified model describing a probable mechanism leading to unbranched spike formation in Triticeae species.  相似文献   

13.
In the present study, we report a survey on a Miniature Inverted Transposable Element (MITE) system known as mPing in 102 varieties of Asian cultivated rice (Oryza sativa L.). We found that mPing populations could be generalized Into two families, mPing-1 and mPing-2, according to their sequence structures. Further analysis showed that these two families of mPing had significant bias in their distribution pattern in two subspecies of rice, namely O. sativa ssp. japonica and indica. 0. sativa japonica has a higher proportion of mPing-1 as a general trait, whereas 0. sativa indica has a higher proportion of roPing-2. We also examined the mPing system In a doubled haploid (DH) cross-breeding population of jingxi 17 (japonica) and zhaiyeqing 8 (indica) varieties and observed that the mPing system was not tightly linked to major subspecies-determining genes. Furthermore, we checked the mPing system in 28 accessions of Asian common wild rice O. rufipogon and found the roPing system in 0. rufipogon. The distribution pattern of the roPing system in O. rufipogon indicated a diphyletlc origin of the Asian cultivated rice O. sativa species. We did not find the mPing system in another 20 Oryza species. These results substantiated a previous hypothesis that O. ruflpogon and O. nivara species were the closest relatives of O. sativa and that the two extant subspecies of O. sativa were evolved independently from corresponding ecotypes of O. ruflpogon.  相似文献   

14.
It is generally accepted that Oryza rufipogon is the progenitor of Asian cultivated rice (O. sativa). However, how the two subspecies of O. sativa (indica and japonica) were domesticated has long been debated. To investigate the genetic differentiation in O. rufipogon in relation to the domestication of O. sativa, we developed 57 subspecies-specific intron length polymorphism (SSILP) markers by comparison between 10 indica cultivars and 10 japonica cultivars and defined a standard indica rice and a standard japonica rice based on these SSILP markers. Using these SSILP markers to genotype 73 O. rufipogon accessions, we found that the indica alleles and japonica alleles of the SSILP markers were predominant in the O. rufipogon accessions, suggesting that SSILPs were highly conserved during the evolution of O. sativa. Cluster analysis based on these markers yielded a dendrogram consisting of two distinct groups: one group (Group I) comprises all the O. rufipogon accesions from tropical (South and Southeast) Asia as well as the standard indica rice; the other group (Group II) comprises all the O. rufipogon accessions from Southern China as well as the standard japonica rice. Further analysis showed that the two groups have significantly higher frequencies of indica alleles and japonica alleles, respectively. These results support the hypothesis that indica rice and japonica rice were domesticated from the O. rufipogon of tropical Asia and from that of Southern China, respectively, and suggest that the indica-japonica differentiation should have formed in O. rufipogon long before the beginning of domestication. Furthermore, with an O. glaberrima accession as an outgroup, it is suggested that the indica-japonica differentiation in O. ruffpogon might occur after its speciation from other AA-genome species.  相似文献   

15.
We propose a simple statistical approach for using Dispersal-Vicariance Analysis (DIVA) software to infer biogeographic histories without fully bifurcating trees. In this approach, ancestral ranges are first optimized for a sample of Bayesian trees. The probability P of an ancestral range r at a node is then calculated as P(rY) = ∑t^n=1 F(rY)t Pt where Y is a node, and F(rY) is the frequency of range r among all the optimal solutions resulting from DIVA optimization at node Y, t is one of n topologies optimized, and Pt is the probability of topology t. Node Y is a hypothesized ancestor shared by a specific crown lineage and the sister of that lineage "x", where x may vary due to phylogenetic uncertainty (polytomies and nodes with posterior probability 〈 100%). Using this method, the ancestral distribution at Y can be estimated to provide inference of the geographic origins of the specific crown group of interest. This approach takes into account phylogenetic uncertainty as well as uncertainty from DIVA optimization. It is an extension of the previously described method called Bayes-DIVA, which pairs Bayesian phylogenetic analysis with biogeographic analysis using DIVA. Further, we show that the probability P of an ancestral range at Y calculated using this method does not equate to pp*F(rY) on the Bayesian consensus tree when both variables are 〈 100%, where pp is the posterior probability and F(rY) is the frequency of range r for the node containing the specific crown group. We tested our DIVA-Bayes approach using Aesculus L., which has major lineages unresolved as a polytomy. We inferred the most probable geographic origins of the five traditional sections of Aesculus and ofAesculus californica Nutt. and examined range subdivisions at parental nodes of these lineages. Additionally, we used the DIVA-Bayes data from Aesculus to quantify the effects on biogeographic inference of including two wildcard fossil taxa in phylogenetic analysis. Our analysis resolved the geographic  相似文献   

16.
Interesting results may arise by combining studies on the structure and function of ecosystems with that of biodiversity for certain species. Grasshopper biodiversity is the result of the evolution of grassland ecosystems; however, it also impacts on the structure and the function of those ecosystems. We consider there to be a close relationship between the health of grassland ecosystems and grasshopper biodiversity. The main problems involved in this relationship are likely to include: (i) grasshopper biodiversity and its spatial pattern; (ii) the effect of grasshopper biodiversity on the ecological processes of grassland ecosystems; (iii) the biodiversity threshold of grasshopper population explosions; (iv) the relationship between grasshopper biodiversity and the natural and human factors that affect grassland ecosystems; and (v) grasshopper biodiversity and the health of grassland ecosystems. The solutions to these problems may provide sound bases for controlling disasters caused by grasshoppers and managing grassland ecosystems in the west of China. In this paper, we introduced two concepts for grasshopper biodiversity, that is, "spatial pattern" and "biodiversity threshold". It is helpful to understand the action of the spatial pattern of grasshopper biodiversity on the ecological processes of grassland ecosystems and the effect of this spatial pattern on the health of those ecosystems, owing to the fact that, in the west of China, grasslands are vast and grasshoppers are widely distributed. Moreover, we inferred that the change in the level of component richness at each type of grasshopper biodiversity can make an impact on grassland ecosystems, and therefore, there is likely to be a threshold to grasshopper biodiversity for the stability and the sustainability of those ecosystems.  相似文献   

17.
Virus-induced gene silencing (VIGS) has been shown to be effective for transient knockdown of gene expression in plants to analyze the effects of specific genes in development and stress-related responses. VlGS is well established for studies of model systems and crops within the Solanaceae, Brassicaceae, Leguminaceae, and Poaceae, but only recently has been applied to plants residing outside these families. Here, we have demonstrated that barley stripe mosaic virus (BSMV) can infect two species within the Zingiberaceae, and that BSMV-VIGS can be applied to specifically down-regulate phytoene desaturase in the culinary ginger Zingiber officinale. These results suggest that extension of BSMV-VlGS to monocots other than cereals has the potential for directed genetic analyses of many important temperate and tropical crop species.  相似文献   

18.
A molecular phylogenetic analysis of most of the species of Perezia reveals that, as traditionally defined, the genus is not monophyletic with two species more closely related to Nassauvia than to Perezia. In addition, our results show that Burkartia (Perezia) lanigera is related to Acourtia and is the only member of that clade in South America. The remaining species are monophyletic and show a pattern of an early split between a western temperate and an eastern subtropical clade of species. Within the western clade, the phylogeny indicates a pattern of diversification that proceeded from southern, comparatively low-elevation habitats to southern high-elevation habitats, and ultimately into more northern high-elevation habitats. The most derived clades are found in the high central Andes, where significant radiation has occurred.  相似文献   

19.
Human immunodeficiency virus (HIV) is the infectious agent causing acquired immu-nodeficiency syndrome (AIDS),a deadliest scourge of human society. Hepatitis C virus (HCV) is a major causative agent of chronic liver disease and infects an estimated 170 million people worldwide,resulting in a serious public health burden. Due to shared routes of transmission,co-infection with HIV and HCV has become common among individuals who had high risks of blood exposures. Among hemophiliacs the co-infection rate accounts for 85%; while among injection drug users (IDU) the rate can be as high as 90%. HIV can accelerate the progression of HCV-related liver disease,particularly when immunodeficiency has developed. Although the effect of HCV on HIV infection is controversial,most studies showed an increase in mortality due to liver disease. HCV may act as a direct cofactor to fasten the progression of AIDS and decrease the tolerance of highly active antiretroviral therapy (HARRT). Conversely,HAART-related hepatotoxicity may enhance the progression of liver fibrosis. Due to above complications,co-infection with HCV and HIV-1 has imposed a critical challenge in the management of these patients. In this review,we focus on the epidemiology and transmission of HIV and HCV,the impact of the two viruses on each other,and their treatment.  相似文献   

20.
Bauhinia blakeana Dunn is the Hong Kong Special Administrative Region emblem and a popular horticultural species in many Asian countries. It was first described as a new species from Hong Kong almost a century ago. This plant is sterile and has long been considered a hybrid, possibly from two related species, B. purpurea and B. variegata. However, not much evidence based on molecular methods was available to support this hypothesis. In this study, sequences of internal transcribed spacer I (ITS1), rbcL and atpB-rbcL intergenic spacer for five Bauhinia species and two varieties of one of the species were determined and compared. There were two types of ITS1 sequences in B. blakeana, one indistinguishable from that of B. purpurea and the other one identical to that of B. variegata. This confirmed that B. blakeana was a hybrid of these two species. Chloroplast atpB-rbcL intergenic spacer sequence of B. blakeana was identical to that of B. purpurea, indicating that B. purpurea was the female parent. The hybridization event seemed to occur only recently and was a rare incident. Its occurrence was likely facilitated by interspecific pollen competition. It appeared that human efforts played a crucial role in the preservation and ubiquity of B. blakeana.  相似文献   

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