首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
An analysis of the frequency of H63D (c.187C>G) mutations in the HFE gene in 19 populations from Central Eurasia demonstrated that the distribution of the mutation in the region of interest was not uniform and that there were the areas of H63D accumulation. The investigation of three polymorphic variants, c.340+4T>C (rs2071303, IVS2(+4)T>C), c.893-44T>C (rs1800708, IVS4(-44)T>C), and c.1007-47G>A (rs1572982, IVS5(-47)A>G), in the HFE gene in individuals homozygous for H63D mutations in the HFE gene revealed the linkage of H63D with three haplotypes, *CTA, *TTG, and *TTA. These findings indicated the partial spread of the mutation in Central Eurasia from Western Europe, as well as the possible repeated appearance of the mutation on the territory on interest.  相似文献   

3.
The history of the study and review of generic and species diversity of Mesozoic rissoid gastropods are provided. The generic composition of Jurassic rissoid gastropods is revised, so that it is proposed to regard them as the family Rissoidae, comprising the genera Bralitzia, Buvignieria, Palaeoceratia, and Palaeorissoina. It is tentatively proposed to assign the genus Hudlestoniella to Rissoidae; this is caused by insufficient morphological knowledge of this genus. The family Palaeorissoidae is regarded as a synonym of Rissoidae. Stratigraphical and geographical distribution of Rissoidae genera is reviewed. From the Jurassic of European Russia, the following species of the genus Buvignieria are described: B. calloviana Gründel, B. imminuera Gründel, B. paucicostata Gründel, B. eichwaldiana (Rouillier), B. choroshovensis Gerasimov, and B. gruendeli sp. nov. The morphological characteristics and stratigraphical distribution of these species are provided. Based on extensive material, the taxonomic significance of particular conchological characters for the establishment of species is discussed.  相似文献   

4.
Coffea arabica (the Arabica coffee) is an allotetraploid species originating from a recent hybridization between two diploid species: C. canephora and C. eugenioides. Transposable elements can drive structural and functional variation during the process of hybridization and allopolyploid formation in plants. To learn more about the evolution of the C. arabica genome, we characterized and studied a new Copia LTR-Retrotransposon (LTR-RT) family in diploid and allotetraploid Coffea genomes called Divo. It is a complete and relatively compact LTR-RT element (~5 kb), carrying typical Gag and Pol Copia type domains. Reverse Trancriptase (RT) domain-based phylogeny demonstrated that Divo is a new and well-supported family in the Bianca lineage, but strictly restricted to dicotyledonous species. In C. canephora, Divo is expressed and showed a genomic distribution along gene rich and gene poor regions. The copy number, the molecular estimation of insertion time and the analysis at orthologous locations of insertions in diploid and allotetraploid coffee genomes suggest that Divo underwent a different and recent transposition activity in C. arabica and C. canephora when compared to C. eugenioides. The analysis of this novel LTR-RT family represents an important step toward uncovering the genome structure and evolution of C. arabica allotetraploid genome.  相似文献   

5.
Shell chirality among Cambrian gastropods is discussed. It is demonstrated that the earliest members of the class include chiral aberrations with abnormal opposite coiling of the shell. It is assumed that, in Cambrian gastropods, speciation could have occurred by mutation in the locus determining the chirality, as is proposed for extant gastropods. In contrast to modern gastropods, the existence of chiral morphs within single species has not been recorded in Cambrian mollusks, whereas the presence of chiral twin species is possible. The systematic position of sinistral representatives of the genus Aldanella Vostokova, 1962 is considered. Aldanella golubevi sp. nov. with sinistral shell is described from the base of the Tommotian Stage of the Anabar Region. Aberrant sinistral specimens of the normally dextral species Aldanella utchurica Missarzhevsky in Rozanov et al., 1969 and Pelagiella adunca Missarzhevsky in Rozanov et al., 1969 are figured.  相似文献   

6.
Morphology of the phosphatic sclerites of the species Mobergella radiolata that come from the Lower Cambrian sections is studied, and the stratigraphic distribution of the species is revised. The sclerite laminated microstructure of this species is described and is shown to be similar to that of some gastropods, bivalves, brachiopods, bryozoans, and corals. The species M. hexactina Skovsted, 2003 and M. sibirica Skovsted, 2003 are shown to be junior synonyms of M. radiolata based on sclerite morphology supported by the results of statistical analysis.  相似文献   

7.
Cryptomeria japonica pollinosis is one of the most serious allergic diseases in Japan; this is a social problem because C. japonica is the most important Japanese forestry species. In order to reduce the amount of pollen dispersed, breeding programs using trees with male-sterile genes have been implemented. High-density linkage maps with stable ordering of markers facilitate the localization of male-sterile genes and the construction of partial linkage maps around them in order to develop markers for use in marker-assisted selection. In this study, a high-density linkage map for C. japonica with 2560 markers was constructed. The observed map length was 1266.2 cM and the mean distance between adjacent markers was 0.49 cM. Using information from this high-density map, we newly located two male-sterile genes (ms3 and ms4) on the first and fourth linkage groups, respectively, and constructed partial linkage maps around these loci. We also constructed new partial linkage maps around the ms1 and ms2 loci using additional SNP markers. The closest markers to the ms1, ms2, ms3, and ms4 male-sterile loci were estSNP04188 (1.8 cM), estSNP00695 (7.0 cM), gSNP05415 (3.1 cM), and estSNP01408 (7.0 cM) respectively. These results allowed us to develop SNP markers tightly linked to the male sterile genes for use in MAS; this will accelerate the future isolation of these genes by map-based cloning approaches.  相似文献   

8.
The review includes seven species, three new species are described: Carpelimus maliensis, C. neuterus, and C. xenosus spp. n. The names Trogophloeus variegatus Cameron, 1944, T. ruandanus Cameron, 1956, and Carpelimus maroccanus Gildenkov, 2004 are synonymized with Carpelimus atomus (Saulcy, 1864). Carpelimus rondaensis is downgraded to the subspecies C. boops rondaensis (Fagel, 1957). Lectotype of Trogophloeus dundoensis Cameron, 1950 is designated. New data on the morphology and distribution of Carpelimus (Troginus) species are given.  相似文献   

9.
A large number of Crassostrea oysters are found in Asia-Pacific. While analyses of interspecific variation have helped to establish historical relationships among these species, studies on intraspecific variation are necessary to understand their recent evolutionary history and current forces driving population biology. We resequenced 18 and analyzed 31 mitogenomes of five Crassostrea species from China: Crassostrea gigas, Crassostrea angulata, Crassostrea sikamea, Crassostrea ariakensis, and Crassostrea hongkongensis. Our analysis finds abundant insertions, deletions, and single-nucleotide polymorphisms in all species. Intraspecific variation varies greatly among species with polymorphic sites ranging from 54 to 293 and nucleotide diversity ranging from 0.00106 to 0.00683. In all measurements, C. hongkongensis that has the narrowest geographic distribution exhibits the least sequence diversity; C. ariakensis that has the widest distribution shows the highest diversity, and species with intermediate distribution show intermediate levels of diversity. Low sequence diversity in C. hongkongensis may reflect recent bottlenecks that are probably exacerbated by human transplantation. High diversity in C. ariakensis is likely due to divergence of northern and southern China populations that have been separated without gene flow. The significant differences in mitogenome diversity suggest that the five sister species of Crassostrea have experienced different evolutionary forces since their divergence. The recent divergence of two C. ariakensis populations and the C. gigas/angulata species complex provides evidence for continued diversification and speciation of Crassostrea species along China’s coast, which are shaped by unknown mechanisms in a north–south divide.  相似文献   

10.
Baikal endemic Benedictia fragilis gastropods distributed in a wide range of depths (from sublittoral to abyssal) of three lake basins are studied. The analysis of the nucleotide sequence of the COI mitochondrial gene fragment and internal transcribed nuclear DNA spacer (ITS1) demonstrates that the studied gastropods are represented in Lake Baikal by three genetic groups. The results of the studies on genetic diversity, phenotypic traits, and distribution allow us to assume that the detected groups are incipient allopatric (geographical) species. On the basis of the data obtained and geological and climatic history of Baikal, possible pathways of the B. fragilis resettlement in the lake and the emergence of three genetic groups are hypothesized.  相似文献   

11.
Colletotrichum cliviae is a fungal species reported both as pathogen and endophyte with broad geographical distribution. Some purported isolates of this species have been assigned to different taxa, including Colletotrichum aracearum, Colletotrichum orchidearum and Colletotrichum. sichuanensis, for which a preliminary analysis of extensive multilocus (ACT, GAPDH, ITS, TUB2) data in this study revealed high sequence similarity with C. cliviae. We further reassessed the species delineation by using the coalescent method of the generalized mixed Yule-coalescent (GMYC) and Poisson Tree Processes (PTP). Single and multilocus gene trees strongly supported a C. cliviae s. lat. clade including the four species. This clade unfolded eight subclades grouped into three distinct lineages, but no monophyly of any of the four species. GMYC and PTP analyses confidently supported the evolutionary independence of these lineages. C. sichuanensis and C. cliviae, except one isolate, formed the largest lineage. The second lineage was made up of isolates named C. aracearum and some of C. orchidearum sharing the haplotype and the third lineage accommodated two isolates named C. cliviae and C. orchidearum. This finding suggests the synonymization of C. sichuanensis with C. cliviae whereas the taxonomic status of C. aracearum and C. orchidearum still needs clarification. This study lays great stress upon the use of comprehensive data for sequence-based characterisation of species in the C. cliviae s. lat. It also presents the first report of C. cliviae in tropical Africa and on citrus host.  相似文献   

12.
Antarctic benthos has been a main target in Antarctic research, but very few quantitative studies have been carried out in the littoral zone, which may be seasonally covered by macroalgae. In this work, we studied (1) cover and biomass of the macroalgae Iridaea cordata and Adenocystis utricularis, and (2) composition of macrobenthic assemblage associated with these macroalgal species at three locations at King George Island: Mareograph Beach (1 M), Tank’s Bay (2R) and Ardley Bay (3R). Iridaea cordata was collected by completely detaching the algae from the substrate, while A. utricularis was scraped. Adenocystis utricularis covered more than 80 % of the substrate at all locations, while coverage of Iridaea cordata was below 53 % or absent (3R). Fresh biomass of I. cordata was 0.8–61.4 g/individual and 4.7–93.0 g/100 cm2 for A. utricularis. The assemblage associated with both macroalgae differed significantly between sites. The studied fauna was composed mainly of amphipods, gastropods and bivalves. Species diversity was higher in the community associated with A. utricularis. A total of ~27 ind/g DW were found associated with I. cordata, while ~112 ind/g DW were found associated with A. utricularis. The most abundant groups associated with I. cordata were amphipods at 1 M (57 %) and gastropods at 2R (46 %). Both groups were responsible for the dissimilarity between localities (62.50 %). The most abundant groups associated with A. utricularis were the gastropods at all localities reaching up to 82 % at 1 M. This study provides a first baseline on the diversity and abundance of benthic assemblages associated with intertidal macroalgae in the southwest of King George Island.  相似文献   

13.
The ants Formica aquilonia and F. lugubris which inhabit the entire forest zone of the North Palaearctic and are absent from the basins of the Yana, Indigirka, and Kolyma rivers were found in the coastal area of the Sea of Okhotsk. A possible climatic conditionality of their occurrence in the Northeast is considered based on the data on the biotopic distribution of ants, the temperature causation of their overwintering, and cold hardiness. On the Sea of Okhotsk coast, these ants overwinter at a depth of 40–200 cm in the soil. During winter, the minimum soil temperature at a depth of 40 cm under the anthill was ?5°C. The supercooling temperature of F. aquilonia was not lower than ?20.2 ± 0.5°C, that of F. lugubris, not lower than ?19.6 ± 0.4°C. Half of F. aquilonia individuals did not survive the daily exposure at ?13°C, F. lugubris, at ?16°C. These two cold-resistant species could inhabit some biotopes of the Kolyma River basin, similar to F. exsecta, F. lemani, and F. sanguinea, but they are absent there for some reasons that are not related to the temperature. A similar cold hardiness is characteristic of F. aquilonia in Estonia (Maavara, 1971, 1985), where it represents a side effect of diapause, since excessive cold hardiness has no adaptive significance for insects overwintering in the non-freezing soils of Estonia. Colonization of Siberia by ant species turned out to be possible only due to the existing cold hardiness, i.e. preadaptation to low temperature. On the Sea of Okhotsk coast, cold hardiness of the ants is non-adaptive due to the relatively mild conditions during winter.  相似文献   

14.
Although reef corals are dependent of the dinoflagellate Symbiodinium, the large majority of corals spawn gametes that do not contain their vital symbiont. This suggests the existence of a pool of Symbiodinium in the environment, of which surprisingly little is known. Reefs around Curaçao (Caribbean) were sampled for free-living Symbiodinium at three time periods (summer 2009, summer 2010, and winter 2010) to characterize different habitats (water column, coral rubble, sediment, the macroalgae Halimeda spp., Dictyota spp., and Lobophora variegata, and the seagrass Thalassia testudinum) that could serve as environmental sources of symbionts for corals. We detected the common clades of Symbiodinium that engage in symbiosis with Caribbean coral hosts A, B, and C using Symbiodinium-specific primers of the hypervariable region of the chloroplast 23S ribosomal DNA gene. We also discovered clade G and, for the first time in the Caribbean, the presence of free-living Symbiodinium clades F and H. Additionally, this study expands the habitat range of free-living Symbiodinium as environmental Symbiodinium was detected in T. testudinum seagrass beds. The patterns of association between free-living Symbiodinium types and habitats were shown to be complex. An interesting, strong association was seen between some clade A sequence types and sediment, suggesting that sediment could be a niche where clade A radiated from a free-living ancestor. Other interesting relationships were seen between sequence types of Symbiodinium clade C with Halimeda spp. and clades B and F with T. testudinium. These relationships highlight the importance of some macroalgae and seagrasses in hosting free-living Symbiodinium. Finally, studies spanning beyond a 1-yr cycle are needed to further expand on our results in order to better understand the variation of Symbiodinium in the environment through time. All together, results presented here showed that the great diversity of free-living Symbiodinium has a dynamic distribution across habitats and time.  相似文献   

15.
In this contribution on the genus Cantharellus in Asia, C. subvaginatus is described from the Republic of Korea as a close relative to the Chinese C. vaginatus, which is here reported for the first time from India. Both species are here placed in Cantharellus subg. Cantharellus sect. Amethystini, together with the Indian C. pseudoformosus (syn.: C. umbonatus) and the Malayan C. subamethysteus. As such, Asia has suddenly become the continent with the highest diversity for Amethystini. Species delimitation in sect. Amethystini is molecularly supported by a combined phylogenetic analysis of rDNA sequences obtained for LSU and ITS and additionally suggests the existence of a still undescribed species in North America. Character variability is discussed for all known members of Amethystini, including atypical specimens of the North American C. lewisii that are morphologically more reminiscent of the South Korean C. subvaginatus.  相似文献   

16.
Propofol (2,6-diisopropylphenol) is one of the safest and most commonly used anaesthetic agents for intravenous general anaesthesia. However, in clinical practice, a large inter-individual variability in response to propofol is observed. To limit the risk of adverse effects, pharmacogenetic investigations are recommended. The aim of our study was to verify the impact of genetic changes c.516G>T in the CYP2B6, c.98T>C in the UGT1A9 and c.1075A>C in the CYP2C9 genes on the individual propofol pharmacokinetic profile in the Polish patients undergoing general anaesthesia. Eighty-five patients from the Department of Anaesthesiology and Intensive Therapy, Regional Hospital in Poznan, Poland, anaesthetised with propofol for surgery, were enrolled in the study. We have genotyped CYP2B6, UGT1A9 and CYP2C9 polymorphisms with the use of pyrosequencing. HPLC measurements of propofol plasma concentration were applied for a pharmacokinetic analysis of the anaesthetic. We identified poor (20), intermediate (42) and rapid (23) metabolisers of propofol, which constituted 24%, 49% and 27% of the group, respectively. Homozygotes c.516 T/T in the CYP2B6 gene were statistically more often found in the rapid metabolisers group (p?<?0.05). However, polymorphisms c.98T>C in the UGT1A9 and c.1075A>C in the CYP2C9 genes did not affect the pharmacokinetic profile of propofol. The mean propofol retention time (MRT) correlated with the patient’s body mass index (BMI) (p?<?0.05). From all the analysed changes, only polymorphism c.516G>T in the CYP2B6 gene and BMI affect the metabolism rate of propofol and may play an important role in the optimisation of propofol anaesthesia.  相似文献   

17.
CIB2 and GJB2 genes variants contribute significantly in familial cases of prelingual recessive hearing loss (HL). This study was aimed to determine the CIB2 and GJB2 variants and associated phenotype in 150 non-familial individuals with HL. After getting informed consent, 150 non-familial deaf patients were enrolled and blood samples were obtained for DNA extraction. Pure tone air conduction audiometry was performed. Coding exons of CIB2 and GJB2 genes were Sanger sequenced. A tetra primer ARMS assay was developed for recurrent CIB2 variant. Four bi-allelic GJB2 variants, c.71G>A p.(Trp24*), c.231G>A p.(Trp77*), c.235delC p.(Leu79Cysfs3*) and c.35delG p.(Gly11Leufs24*), were found in nine hearing impaired individuals. We also found four homozygotes and five carriers of c.380G>A p. (Arg127His) variant of controversial clinical significance. CIB2 sequencing revealed single recurrent variant c.272T>C p. (Phe91Ser) segregating with HL in ten individuals. Among our patients, c.71G>A (p.Trp24*) was the most common variant, accounted for 45% of GJB2 variants. Two known GJB2 variants, c.235delC p. (Leu79Cysfs3*) and c.310del14 p. (Lys105Argfs2*), are reported here for the first time in Pakistani population. Our data further support the benign nature of c.380G>A p. (Arg127His) variant. For CIB2, c.272T>C p. (Phe91Ser) is the second common cause of HL among our sporadic cases. Phenotypically, in our patients, individuals homozygous for GJB2 variants had profound HL, whereas CIB2 homozygotes had severe to profound prelingual HL. Our results suggest that GJB2 and CIB2 are common cause of HL in different Pakistani ethnicities.  相似文献   

18.
Nine new species of scelionids collected in Japan, Israel, and the Ukraine, Calotelea shimurai Kononova et Fursov, C. japonica Kononova, C. stellae Kononova, Calliscelio recens Kononova, C. floridum Kononova, C. parilis Kononova, C. ordo Kononova, Oxyscelio florum Kononova, and O. perpensum Kononova, are described. A brief morphological characteristics of the mentioned genera and some data on the geographical distribution of these species are given. Calotelea shimurai differs from C. striola Kononova in the sculpture of the metasoma (tergites I–III striate, whereas in C. striola striation present only on tergites I and II), fore-wing venation (stigmal vein of C. shimurai 0.43 times as long as postmarginal vein and 1.75 times as long as marginal one; in C. striola, stigmal vein 0.52 times as long as postmarginal vein and 1.3 times as long as marginal one), and the length of the metasoma (in C. shimurai and C. striola, metasoma 4.0 and 2.3 times as long as wide, respectively). Calotelea shimurai parasitizes in eggs of the dragonflies Aeshna nigroflava Martin, Planaeschna milnei Selys, and Boyeria macachlani (Aeshnidae, Odonata). C. japonica is closely related to C. originalis Kozlov and Kononova, but differs from it in the sculpture of the metasoma (metasomal tergites with longitudinal wrinkles against the bright smooth background; in C. originalis, tergites I and II with longitudinal wrinkles against the alveolate background), in the coloration of fore wing (infuscate in C. japonica and dark, with dark transverse stripes in C. originalis). C. stellae differs from C. artus Kozlov and Kononova in the more flattened mesoscutum (C. artus with protruding mesoscutum) and the sculpture of the metasomal tergites (in C. stellae, only petiolus and tergite II striate, while in C. artus, such striation present on tergites I–IV). C. stellae was reared from eggs of unidentified Orthoptera. C. recens is closely related to C. parilis Kononova. It can be distinguished by the fore-wing venation (C. recens has stigmal vein, which is twice as long as marginal vein and 0.66 times as long as postmarginal one; stigmal vein of C. parilis is 3 times as long as marginal vein and 0.83 times as long as postmarginal one), by the sculpture of the metasoma, and coloration of the coxae (yellow in C. recens and black in C. parilis). C. floridum is similar to C. mediterranea Kieffer, but can be identified by the length of the postmarginal vein, which is 3 times as long as the stigmal vein, whereas C. mediterranea has the postmarginal vein, which is only twice as long as the stigmal one. C. floridum also differs in the sculpture of the metasoma (C. floridum has all the metasomal tergites with longitudinal lines, while C. mediterranea has only metasomal petiolus with the same sculpture and tergites II–IV with alveolate sculpture, tergites V and VI are slightly stippled) and in the coloration of the legs, which are yellow (as coxae), while C. mediterranea has brownish black legs. C. parilis resembles C. recens, but differs from it in the fore-wing venation, sculpture of the metasoma, and coloration of the coxae. C. ordo differs from the closely related C. ruficollis Kozlov et Kononova in the head sculpture, which is finely alveolate in C. ordo and finely granulate in C. ruficollis. Oxyscelio florum is closely related to O. perpensum, but differs from it in the coloration of the body and size of the antennal segments, stigmal and postmarginal veins, and metasomal tergites. O. perpensum is closely related to O. florum. The main distinguishing morphological characters are similar to those in O. florum. O. perpensum was reared from eggs of unidentified Orthoptera.  相似文献   

19.
Invasive candidiasis is caused mainly by Candida albicans, but other Candida species have increasing etiologies. These species show different virulence and susceptibility levels to antifungal drugs. The aims of this study were to evaluate the usefulness of the non-conventional model Caenorhabditis elegans to assess the in vivo virulence of seven different Candida species and to compare the virulence in vivo with the in vitro production of proteinases and phospholipases, hemolytic activity and biofilm development capacity. One culture collection strain of each of seven Candida species (C. albicans, Candida dubliniensis, Candida glabrata, Candida krusei, Candida metapsilosis, Candida orthopsilosis and Candida parapsilosis) was studied. A double mutant C. elegans AU37 strain (glp-4;sek-1) was infected with Candida by ingestion, and the analysis of nematode survival was performed in liquid medium every 24 h until 120 h. Candida establishes a persistent lethal infection in the C. elegans intestinal tract. C. albicans and C. krusei were the most pathogenic species, whereas C. dubliniensis infection showed the lowest mortality. C. albicans was the only species with phospholipase activity, was the greatest producer of aspartyl proteinase and had a higher hemolytic activity. C. albicans and C. krusei caused higher mortality than the rest of the Candida species studied in the C. elegans model of candidiasis.  相似文献   

20.
Harmonia axyridis Pallas (1773) (Coleoptera: Coccinellidae) is the well-studied system of invasive insect species. Native and invasive parts of the area of H. axyridis are isolated geographically. We studied the species composition and the distribution of bacterial symbionts Spiroplasma and Rickettsia in seven localities of the native area and six localities of the invasive area of H. axyridis. Rickettsia was detected in H. axyridis populations for the first time. We found that the proportion of beetles infected with Rickettsia in native and invasive populations of H. axyridis is about 0.03. Spiroplasma was found only in native populations of H. axyridis. The proportion of infected individuals with Spiroplasma in native populations of H. axyridis is about 0.08. All studied native populations of H. axyridis are infected with Spiroplasma, while all invasive populations are not. We discuss the possible influence of Spiroplasma and Rickettsia in the formation of invasive populations of H. axyridis.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号