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 15 毫秒
1.
Introduction of non-native fish species has been criticized as one of the major threats to freshwater ecosystems. During recent years, the cyprinid fish genus Carassius has been the subject of various studies in terms of introduction biology and ecology. The taxonomy and identification of described species in the genus Carassius is still ambiguous. In order to increase the knowledge of introduced species of the genus in Iran, molecular approaches were employed to identify species based on the mitochondrial gene, cytochrome b (Cyt b). In total, 417 specimens across Eurasia and some other parts of the world have been analyzed. Afterwards, investigation of the possible origin and pathways of introduction was done using analysis of haplotype networks based on the Cyt b gene. The results revealed that there are three introduced species i.e., Carassius auratus, Carassius gibelio and Carassius langsdorfii, in inland waters of Iran. Carassius langsdorfii was recorded from Iran and western Asia for the first time. Analysis of haplotype network showed various potential sources of introduction for each species in Iran and regions beyond their native distribution ranges.  相似文献   

2.
The genetic constitution and phylogenetic relationships among the proposed species and subspecies of the crucian carp complex in Japan (Carassius cuvieri, C. auratus subspp. 1 and 2, C. a. grandoculis, C. a. buergeri, and C. a. langsdorfii) were investigated based on analyses of the partial nucleotide sequences of the mitochondrial DNA control region and amplified fragment length polymorphisms of nuclear DNA. Our results demonstrate that C. cuvieri and C. auratus are different entities. However, although several distinct lineages were observed for C. auratus, none corresponded to the proposed subspecies. Moreover, the five subspecies of C. auratus were not necessarily separated genetically from each other. Triploid fish, which are currently classified as a single subspecies (C. a. langsdorfii) but are sometimes treated as an independent species, fell into various clades along with diploid individuals of other subspecies that have the same or similar mitochondrial haplotypes. This suggests that gynogenetic triploid crucian carps distributed throughout the Japanese Archipelago have polyphyletic maternal origins. Our results indicate that Japanese crucian carps are a much more complex assemblage than previously believed.  相似文献   

3.
Electron microscope examinations of primary oocytes of gynogenetic triploid ginbuna (Carassius auratus langsdorfii) and diploid gengoroubuna (Carassius auratus cuvieri) were carried out. Typical synaptonemal complexes were observed in both subspecies. In addition, clear differences in PGM-A electrophoretic patterns between a female parent ginbuna and her offspring were detected. It was concluded that synapsis and recombination occur between at least some homologous chromosomes in triploid ginbuna.  相似文献   

4.
To understand the differences in the spawning sites among Cyprininae fishes in Lake Biwa, we conducted periodic sampling of larvae and juveniles at three sites (irrigation ditch, St. 1; river, St. 2; and satellite lake, St. 3). On the basis of species/subspecies identification by using RAPD analysis, we examined the species composition of the larvae and juveniles at these three sampling sites. The number of specimens was 616, 68, and 117 at St. 1, St. 2, and St. 3, respectively. Based on morphological and genetic identification, the specimens were found to include nine fish species/subspecies, namely, Carassius auratus grandoculis, Carassius cuvieri, Carassius auratus langsdorfii, Cyprinus carpio, Sarcocheilichthys sp., Silurus asotus, Oryzias latipes, Odontobutis obscura obscura, and Rhinogobius sp. The species composition at the three sites also differed. Among the Cyprininae fishes, C. auratus grandoculis, C. auratus langsdorfii, and Cyprinus carpio were found in abundance at St. 1; C. cuvieri was not collected from St. 1 but was found at the other two sites, particularly St. 3. Among the other fishes, Rhinogobius sp. was collected at St. 1 and St. 3, whereas the other four occurred only at St. 1. These results suggest that the selection of spawning sites by C. cuvieri differs to a certain extent from that of the other Cyprininae fishes, and the irrigation ditch in the lake is an important habitat for the larvae and juveniles of native fish species.  相似文献   

5.
Summary Electrofocusing of carboxymethylated, crystalline Fraction I proteins in polyacrylamide gels containing 8 M urea resolves the large subunit into three major peptides and the small subunit into one or more peptides. Electrofocusing of proteins isolated from leaves of the reciprocal, F1, hybrids: N. glutinosa x N. tabacum, N. glauca x N. tabacum, N. glauca x N. langsdorfii and the parental species confirms that coding information for the large subunit is inherited only by the maternal line whereas both parents contribute coding information for the small subunit. The analysis shows that one or more of the three peptides of the large subunit of Fraction I proteins from different Nicotiana species differ in isoelectric point and therefore serve as phenotypic markers for chloroplast DNA genes.  相似文献   

6.
Edoardo Biondi 《Plant biosystems》2013,147(5-6):227-233
Abstract

Taxodioxylon gypsaceum (Göppert) Kräusel, wood fossil discovered in the central italian miocene.—A sample of silicified wood fossil has been discovered in the miocenic formations of the Castellaro mountain in the neighbourhood of Pesaro a city in Central Italy. An anatomical study has made it possible to accept that the species is Taxodioxylon gypsaceum, which resembles the actual Sequoia sempervirens for its woody structure, conservative endemism of a coastal region in California. The fossil species that is known for its numerous tertiary deposits in the Northern, Central and Eastern Europe, is now indicated for the first time in Italy; the mount Castellaro station results to be the more south among those in Europe.

Various paleobotanical data concerning traces of leaves, fruits and seeds gathered in localities near to the deposit and in the region complies with the discovery of Taxodioxylon gypsaceum because of the presence of varions species of Sequoia and Taxodium and in particular of the Sequoia langsdorfii leaves which is considered as the ancient form of the Sequoia sempervirens.  相似文献   

7.
Carassius RFamide (C-RFa) is a brain-gut peptide, isolated originally from the brain of a teleost fish, Japanese crucian carp (Carassius auratus langsdorfii). It is a novel FMRFamide-related peptide sharing homologies with mammalian prolactin-related peptide. We observed the localization of C-RFa-like immunoreactivity (C-RFa-IR) in the stomach, intestine, and pancreas of Japanese butterfly ray using an immunohistochemical technique. In the whole gastrointestinal tract, C-RFa-IR was observed in smooth muscle cells, and in the Meissner’s and Auerbach’s plexus ganglia. Furthermore, in the stomach C-RFa-IR was also observed at the bottom of the fundic glands in both the body and pyloric region. In the intestine C-RFa-IR was observed in epithelial cells at the tip of mucosal folds. In the pancreas, C-RFa-IR was observed in islet cells. Thus, we suggest that ray C-RFa may have functional roles in both peripheral neurotransmission and endocrine function of the gastroenteropancreatic system.  相似文献   

8.
In teleost fish, a novel gene G6F-like was identified, encoding a type I transmembrane molecule with four extracellular Ig-like domains and a cytoplasmic tail with putative tyrosine phosphorylation motifs including YxN and an immunoreceptor tyrosine-based activation motif (ITAM). G6F-like maps to a teleost genomic region where stretches corresponding to human chromosomes 6p (with the MHC), 12p (with CD4 and LAG-3), and 19q are tightly linked. This genomic organization resembles the ancestral “Ur-MHC” proposed for the jawed vertebrate ancestor. The deduced G6F-like molecule shows sequence similarity with members of the CD4/LAG-3 family and with the human major histocompatibility complex-encoded thrombocyte marker G6F. Despite some differences in molecular organization, teleost G6F-like and tetrapod G6F seem orthologous as they map to similar genomic location, share typical motifs in transmembrane and cytoplasmic regions, and are both expressed by thrombocytes/platelets. In the crucian carps goldfish (Carassius auratus auratus) and ginbuna (Carassius auratus langsdorfii), G6F-like was found expressed not only by thrombocytes but also by erythrocytes, supporting that erythroid and thromboid cells in teleost fish form a hematopoietic lineage like they do in mammals. The ITAM-bearing of G6F-like suggests that the molecule plays an important role in cell activation, and G6F-like expression by erythrocytes suggests that these cells have functional overlap potential with thrombocytes.  相似文献   

9.
The asexual all-female Japanese crucian carp, Carassius auratus langsdorfii (Teleostei: Cypriniformes), reproduces gynogenetically, relying on the sperm of males of the sexual "host," C. auratus subspp. Theoretically, frequency-dependent mating preference of males to conspecific females can lead to the coexistence of asexual and sexual fish, if all else is equal. Our specific questions are whether males prefer conspecific females over asexual females and whether individuals show dominance hierarchies that potentially cause frequency-dependent mating preference. In an individual choice experiment, a tank was partitioned into three compartments with the middle one for a single male and the two outer ones for a sexual and an asexual female. The males of C. auratus bürgeri demonstrated a significant preference for ovulated conspecific females over ovulated asexual females. In contrast, in a group mating experiment, a single experimental tank included two males, a sexual female, and an asexual female together, and males chased and mated with both asexual and sexual females equally. Male mate preference was weak in group mating, which is typical in natural populations. Males and females of crucian carp showed no apparent agonistic behavior to each other in the group mating experiment. This is different from other gynogenetic complexes with the dominance hierarchy of males showing strong frequency-dependent mating preference (e.g., Poeciliopsis). We conclude that male mate preference is unlikely to be a strong frequency-dependent force maintaining the coexistence of asexual–sexual complexes of Japanese crucian carp. Received in revised form: 5 February 2001 Electronic Publication  相似文献   

10.
Herbaceous vegetation was examined in an Otanoshike wetland in northern Japan to clarify the relationships between vegetation patterns and environmental factors with different scales. Alders (Alnus japonica) have recently invaded and might modify the herbaceous vegetation. In total, 150 50×50cm plots were established on the transitional areas between alder thickets and grassy marshland. Cover was measured for the vascular plant taxa, and canopy area, number of stumps, number of mounds, water depth, elevation difference, litter thickness, soil organic matter, and soil pH were measured in each plot. TWINSPAN cluster analysis classified four vegetation groups: (i), grasslands represented by Phragmites australis, Trientalis europaea, Lythrum salicaria, and Hosta rectifolia; (ii), Calamagrostis langsdorfii, and Polygonum thunbergii grasslands with Spiraea salicifolia; (iii), reed swamp dominated by Phragmites australis, and (iv), marshland dominated by Carex lyngbyei. Canonical correspondence analysis indicated that water depth primarily divided vegetation groups 1–2 and 3–4. Alder established in drier sites mostly by re-sprouting, and the canopy affected light and soil conditions on the ground surface. The second axis of canonical correspondence analysis was related to the canopy area and soil pH, and explained the vegetation differentiation between groups 1 and 2, and groups 3 and 4. In conclusion therefore, scale-dependent or hierarchical variables affected the vegetation patterns in different ways, that is, the herbaceous vegetation was first differentiated by water depth that was corresponding to alder establishment on a large scale, and subsequent light and soil conditions were second determinants on a small scale.  相似文献   

11.
The phylogenetic relationships of Carassius genus subspecies were investigated based on the data of the variability of nucleotide sequences of the mtDNA cytochrome b (cyt b) and control region (CR). Dendrograms constructed based on the BA, ML, NJ, and MP methods revealed five clusters of the congruent topologies that substantially corresponded to geographical localities and taxonomic conception of the C. auratus complex. An analysis of two mtDNA fragment topologies demonstrated that the island forms of Japanese crucian carps C. cuvieri and C. auratus langsdorfii diverged later compared to the divergence of continental C. auratus forms (4.0?C4.5 mln years ago, by molecular calibration). Among the continental silver crucian carps, C. a. gibelio forms two clusters corresponding to two phylogroups with a mean uncorrected genetic distance p = 0.044. The genealogical combination of haplotypes with the first C. a. gibelio phylogroup was observed in C. auratus clade. According to the data of mtDNA analysis, these subspecies represent sister lineages with a level of intergroup divergence of p = 0.022?C0.036. No genetic differences were observed between diploid (except for the two C. a. gibelio phylogroups) and polyploid C a. auratus, as well as monophyly in polyploid forms. New approaches based on a comparative study of the nuclear markers might help to unravel the origin of gynogenetic forms and phylogenetic relationships within the C. auratus complex.  相似文献   

12.
Cytotoxic T cells (CTLs) constitute an important component of the specific effector mechanism in killing against microbial-infected or transformed cells. In addition to these activities, recent studies in mammals have suggested that CTLs can exhibit direct antimicrobial activity. Therefore, the present investigation was conducted to find out the microbicidal activity of CD8α+ T cells of ginbuna crucian carp, Carassius auratus langsdorfii. The CD8α+ T cells from immunised ginbuna exhibited the antibacterial activity against both facultative intracellular bacteria and extracellular bacteria. The maximum reduction of viable count of pathogens was recorded with effector (sensitized) cells and target (bacteria) ratio of 10:1 co-incubated for a period of 1–2 h at 26 °C when effector cells were derived from ginbuna 7 days after one booster dose at 15th day of primary sensitization/immunisation. Sensitized CD8α+ T cells are found to kill 92.1 and 98.9% of Lactococcus garvieae and Edwardsiella tarda, respectively. No significant difference in the bacterial killing activity could be recorded against facultative intracellular bacteria and extracellular bacteria. The specificity study indicated the non-specific killing of bacteria. CD8α+ T cells from E. tarda immunised ginbuna exhibited 40% of non-specific killing activity against L. garvieae and those from L. garvieae immunised ginbuna showed 42.7% of non-specific killing activity against E. tarda. Furthermore, CD4+ T cells also killed 88% and 95.7% of L. garvieae and E. tarda, respectively. In addition to T cell subsets, surface IgM+ cells also killed both types of pathogens. Therefore, the present study demonstrated the direct antibacterial activity of CD8α+, CD4+ T-cells and surface IgM+ cells in fish.  相似文献   

13.
A taxonomic review of the Korean Lymantria Hübner, 1819 was conducted. A total of nine species of five subgenera with two unrecorded species are listed: Lymantria (Porthetria) dispar Linnaeus 1758, L. (P.) xylina Swinhoe 1903, L. (Lymantria) monacha (Linnaeus 1758), L. (L.) minomonis Matsumura 1933 (new to Korea), L. (L.) similis monachoides Schintlimeister 2004 (new to Korea), L. (L.) lucescens (Butler 1881), L. (Nyctria) mathura Moore 1865, L. (Collentria) fumida Butler 1877, and L. (Spinotria) bantaizana Matsumura 1933. Lymantria (Lymantria) minomonis and L. (L.) similis monachoides are newly added to the Korean fauna. Lymantria (L.) minomonis was found only on Bogildo Island of Jeollanam‐do in the southern part of Korea, and L. (L.) similis monachoides was collected in central Korea. Lymantria (Porthetria) xylina and L. (Collentria) fumida were not examined in this study, and it is considered that the previous records were due to misidentification or they are only distributed in the northern part of the Korean Peninsula. We provide diagnoses of two unrecorded species and adult habitus and genitalia photos of the Korean Lymantria species.  相似文献   

14.
15.
The S locus and its flanking regions in the genus Prunus (Rosaceae) contain four pollen-expressed F-box genes. These genes contain the S locus F-box genes with low allelic sequence polymorphism genes 1, 2, and 3 (SLFL1, SLFL2, and SLFL3) as well as the putative pollen S gene, named the S haplotype-specific F-box protein gene (SFB). As much less information is available on the function of SLFLs than that of SFB, we analyzed the SLFLs of six S haplotypes of sweet cherry (Prunus avium) in this study. Genomic DNA blot analysis and the isolation of SLFL1 showed that the SLFL1 gene in a functional self-incompatible S 3 haplotype is deleted and only a partial sequence resembling SLFL1 is left in the S 3 locus region, suggesting that SLFL1 by itself is not directly involved in either the GSI reaction or pollen-tube growth. Genomic DNA blot analysis showed that there was no substantial modification or mutation in SLFL2 and SLFL3. A phylogenic analysis of F-box genes in the rosaceous S locus and its border regions showed that Prunus SLFLs were more closely related to maloid S locus F-box brothers than to Prunus SFBs. The functions of SLFLs and the evolution of self-incompatibility in Prunus are discussed based on these results. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. The nucleotide sequence data reported appear in the DDBJ, EMBL, and GenBank Nucleotide Sequence Databases under the accession numbers, AB360339, AB360340, AB360341, and AB360342, for SLFL1-S 1 , SLFL1-S 2 , SLFL1-S 5 , and SLFL1-S 6 , respectively.  相似文献   

16.
17.
18.
Endosymbiotic Wolbachia bacteria are, to date, considered the most widespread symbionts in arthropods and are the cornerstone of major biological control strategies. Such a high prevalence is based on the ability of Wolbachia to manipulate their hosts' reproduction. One manipulation called cytoplasmic incompatibility (CI) is based on the death of the embryos generated by crosses between infected males and uninfected females or between individuals infected with incompatible Wolbachia strains. CI can be seen as a modification‐rescue system (or modresc) in which paternal Wolbachia produce mod factors, inducing embryonic defects, unless the maternal Wolbachia produce compatible resc factors. Transgenic experiments in Drosophila melanogaster and Saccharomyces cerevisiae converged towards a model where the cidB Wolbachia gene is involved in the mod function while cidA is involved in the resc function. However, as cidA expression in Drosophila males was required to observe CI, it has been proposed that cidA could be involved in both resc and mod functions. A recent correlative study in natural Culex pipiens mosquito populations has revealed an association between specific cidA and cidB variations and changes in mod phenotype, also suggesting a role for both these genes in mod diversity. Here, by studying cidA and cidB genomic repertoires of individuals from newly sampled natural C. pipiens populations harbouring wPipIV strains from North Italy, we reinforce the link between cidB variation and mod phenotype variation fostering the involvement of cidB in the mod phenotype diversity. However, no association between any cidA variants or combination of cidA variants and mod phenotype variation was observed. Taken together our results in natural C. pipiens populations do not support the involvement of cidA in mod phenotype variation.  相似文献   

19.
 For the angiosperm dominants of northern California’s mixed evergreen forests, this study compares the display of photosynthetic tissue within leaves and along branches, and examines the correspondence between these morphological attributes and the known environmental tolerances of these species. Measurements were made on both sun and shade saplings of six species: Arbutus m e n z i e s i i (Ericaceae), C h r y s o l e p i s c h r y s o p h y l l a (Fagaceae), L i t h o c a r p u s d e n s i f l o r u s (Fagaceae), Quercus c h r y s o l e p i s (Fagaceae), Quercus w i s l i z e n i i (Fagaceae), and Umbellularia c a l i f o r n i c a (Lauraceae). All species had sclerophyllous leaves with thick epidermal walls, but species differed in leaf specific weight, thickness of mesophyll tissues and in the presence of a hypodermis, crystals, secretory idioblasts, epicuticular deposits, and trichomes. The leaves of Arbutus were 2 – 5 times larger than those of C h r y s o l e p i s, L i t h o c a r p u s and Umbellularia and 4 – 10 times larger than those of both Quercus species. Together with differences in branch architecture, these leaf traits divide the species into groups corresponding to environmental tolerances. Shade-tolerant C h r y s o l e p i s, L i t h o c a r p u s, and Umbellularia had longer leaf lifespans and less palisade tissue, leaf area, and crown mass per volume than the intermediate to intolerant Arbutus and Quercus. Having smaller leaves, Quercus branches had more branch mass per leaf area and per palisade volume than other species, whereas Arbutus had less than other species. These differences in display of photosynthetic tissue should contribute to greater growth for Quercus relative to the other species under high light and limited water, for Arbutus under high light and water availability, and for C h r y s o l e p i s, L i t h o c a r p u s, and Umbellularia under limiting light levels. Accepted: 22 March 1996  相似文献   

20.
Functions of α‐ and β‐branch carotenoids in whole‐plant acclimation to photo‐oxidative stress were studied in Arabidopsis thaliana wild‐type (wt) and carotenoid mutants, lut ein deficient (lut2, lut5), n on‐p hotochemical q uenching1 (npq1) and s uppressor of z eaxanthin‐l ess1 (szl1) npq1 double mutant. Photo‐oxidative stress was applied by exposing plants to sunflecks. The sunflecks caused reduction of chlorophyll content in all plants, but more severely in those having high α‐ to β‐branch carotenoid composition (α/β‐ratio) (lut5, szl1npq1). While this did not alter carotenoid composition in wt or lut2, which accumulates only β‐branch carotenoids, increased xanthophyll levels were found in the mutants with high α/β‐ratios (lut5, szl1npq1) or without xanthophyll‐cycle operation (npq1, szl1npq1). The PsbS protein content increased in all sunfleck plants but lut2. These changes were accompanied by no change (npq1, szl1npq1) or enhanced capacity (wt, lut5) of NPQ. Leaf mass per area increased in lut2, but decreased in wt and lut5 that showed increased NPQ. The sunflecks decelerated primary root growth in wt and npq1 having normal α/β‐ratios, but suppressed lateral root formation in lut5 and szl1npq1 having high α/β‐ratios. The results highlight the importance of proper regulation of the α‐ and β‐branch carotenoid pathways for whole‐plant acclimation, not only leaf photoprotection, under photo‐oxidative stress.  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