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2011年  第32卷  第6期

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A phylogenetic hypothesis for the Asian newts of the Tylototriton asperrimus group was generated using data from two mitochondrial fragments including COI and the ND1-ND2 regions. Four distinct clades (A, B, C, D) were resolved with high nodal support within this monophyletic group. Clade A included T. asperrimus, T. hainanensis, T. notialis, “T. vietnamensis”, and two unnamed salamander populations from Vietnam. Clade A, constituted the sister group of clades B + C. Newly identified clade C likely represents a new cryptic species. Clade C was the sister group of T. wenxianensis. The true T. vietnamensis exclusively constituted clade D. Our results bring into question some previous taxonomic decisions, and a revision is required. This study illustrates the necessity to include samples from type localities in taxonomic studies, and highlights the importance of fine-grained geographical sampling.
Origin and evolution of new genes contribute a lot to genome diversity. New genes usually form chimeric gene structures through DNA-based exon shuffling and generate proteins with novel functions. We investigated polymorphism of 14 chimeric new genes in Drosophila melanogaster populations and found that eight have premature stop codons in some individuals while six are intact in the population, four of which are under negative selection, suggesting the two evolutionary fates of new chimeric genes after origination: accumulate premature stop codons and pseudolize, or acquire functions and get fixed by natural selection. Different from new genes originated through RNA-based duplication (retroposition) which are usually testis-specific or male-specific expressed, the expression patterns of these new genes through DNA-based exon shuffling are temporally and spatially diverse, implying that they may have the potential to evolve various biological functions despite that they may become pseudogenes or non-protein-coding RNA genes.
Abstract: Taimen (Hucho taimen) is a native fish species in China and it is in the state of endangerment. To explain clearly the genetic diversity and genetic structure, 9 wild populations of taimen were investigated using 20 microsatellite markers. The results showed that their observed heterozygosity ranged from 0.0994 to 0.8882, the expected heterozygosity varied from 0.2005 to 0.8759, and the range of PIC index was from 0.3432 to 0.5261 while population from Huma River had low genetic diversity. Fst of matching group ranged from 0.0246 to 0.2333 (P<0.0001)and Nm varied among 0.8216 to 9.9292, which indicated that the genetic differentiation was remarkable among populations.The half/full-sib family tests detected a proportion of half/full-sib family groups varying among 27.78% to 90.91%, showing a high inbred pressure and a risk ofbottlenecks experienced by most groups. The AMOVA results showed that the global Fst was 0.1081; the clustering result showed that individuals from Beiji tributary of Heilongjiang River clustered as one clade, all individuals from Huma River and Wusuli River clustered as one clade and all individuals from the upper reaches of the Heilongjiang River clustered as another clade. All these results indicated that the decrease of taimen resource has affected the gene exchange among their populations. In order to achieve full protection of taimen germplasm resources, we should put an end to the destructive fishing for taimen and promotegene exchange among their populations.
ATP-binding cassette transporters (ABCT) could generate multiple transcripts through alternative splicing (AS) in mammalian. Some AS introduced PTC (premature terminal codon)-containing isoforms of ABCT couple with NMD (nonsense-mediated mRNA decay) to regulate relevant functions. However, there are no similar reports in lower organisms. This paper focuses on the unicellular protozoa Tetrahymena thermophila, based on the RNA-seq data of Tetrahymena thermophila, identified two alternative splicing variants of gene ABCC10 (SV1 and SV2). The SV2 contained an intron retention event at the fifth intron, and this 49 bp-intron resulted in shift-frame and introduced PTC. Then, a knock-down Tetrahymena strain of gene UPF1 which is a key factor of NMD was constructed, and the expression levels of SV2 were performed using a real-time quantitative PCR. The results showed the expression levels of SV2 were up-regulated significantly in knock-down strain, indicating that SV2 was targeted by NMD, which is consistent to the mechanism which the AS introduced PTC-containing isoforms of ABCC proteins can be targeted by NMD in mammalian. Thus, we infer that this mechanism is highly evolutionary conserved in eukaryotes and was already functional in the last eukaryotic common ancestor.
Recent evidences indicate that retinal muller cells exhibit retinal progenitor characteristics under certain condition in chick, rat and human. However, there is no report on nonhuman primate, a close relative to human. In this study, we first established a muller cell line of rhesus monkey expressing GS, vimentin, CRALBP, EGFR, barely GFAP, which resemble the expression profile of human muller cells, differ from that of rodent. Expression of pax6, nestin, sox2, otx2, six6, and six3 was detected after one week culture in neural stem cell medium. Further culture with retinoic acid induced some cells differentiate toward neuron. These results suggest that primate muller cell is capable of dedifferentiating to retinal progenitors, which may serve as a potential cell source for cell therapy to treat retinal degenerative diseases.
Human ALR gene sequence was amplified by PCR from human total DNA and inserted into pIRES2-EGFP vector. The bicistronic eukaryotic expression vector, pIRES-EGFP/ALR, expressing EGFP, Neor and ALR genes was constructed. Sheep fetal fibroblast cells (sEFCs) were transfected with pIRES-EGFP/ALR by the induction of lipofectAMINETM. The positive cell clones were selected with medium containing G418 (800 µg/ml). The fluorescence of transgenic cells was examined with a confocal laser scanning microscope. The expression of ALR gene was tested by PCR, RT-PCR and immuno-histochemical staining. The transgenic cells were used as donors for nuclear transfer to enucleated ovine oocytes. Transgenic embryos were tested by confocal laser scanning microscope and immuno -histochemical staining. Results showed that the EGFP and ALR genes linked with IRES were coexpressed simultaneously in sFFCs; the blastocysts formed by nuclear transfer using tranfected donor cells are all transgenic blastocysts. EGFP, ALR and Neor gene were all expressed in the transgenic embryos. In conclusion that a method to construct the positive embryos before pre-implantation which stably express ALR gene by the indication of EGFP expression has been successfully established. The application of this method can simplify the procedure of testing the targets and contribute to the efficiency increasing of transgenic domestic animal production.
From December 2009 to May 2010 goose and duck (Anatidae) community censuses in winter and shorebird (Charadriiforms) community censuses in spring were conducted across three types artifical wetlands (urban lake wetland, restorative wetland, abandoned wetland) along the coast of Nanhui, Shanghai. Correlation analyses were undertaken between community indices and habitat factors. The results showed there were significant differences in the density of geese and ducks among the wetlands, but no difference in the number of species. The density of geese and ducks in the restorative wetland was 3.77 times that of abandoned wetland and 6.03 times that of urban lake wetlands. The number of species and density of shorebirds in restorative wetlands was 2.88 and 5.70 times that of abandoned wetlands. We found significant differences in the number and density of shorebird species between restorative and abandoned wetlands. The number of species density of geese and ducks and the Shannon-Wiener (H′) index were positively correlated with water area. The number of species and H′ were negatively correlated with vegetation area. The number of species, species density and H′ and evenness were negatively correlated with vegetation coverage. H′ was positively correlated with mean water level. The results showed that the number and density of shorebird species were positively correlated with bare muddy areas. Aquaculture ponds and paddy fields in reclaimed area is efficient sufficient compensation mechanism to maintain more water areas for waterbirds and to control vegetation expansion and maintain shorebird habitat after coastal reclamation.
Waterbird surveys were conducted regularly in the Qiantangjiang River estuary and Hangzhou Bay from July 2007 to November 2011. A total of 128 species (nine orders and 18 families) were recorded, including 119 migrants which accounted for 93% of the total species; eleven species were listed as National Protected Species. Inter-specific correlation analysis for 13 shorebird populations and nine duck populations recorded over time found that 21 pairs of shorebirds and 23 pairs of ducks were correlated. By looking at seasonal dynamics and migration patterns we were able to divide the migration process into six stages: (1) late July to late September was the migration peak of shorebirds, which were dominated by Limosa limosa, Calidris ruficollis and Charadrius mongolus. (2) Early October to mid-December was the migration peak of wintering migrants of shorebirds and ducks, which were the first two large groups in our study areas. (3) Late December to mid-February was the wintering period of migration waterbirds. (4) Late February to late March was the peak migration of ducks and the winter migrants of shorebirds dominated by.Calidris alpina. (5) Early April to mid-May was the migration peak of passage migrants such as, Calidris ruficollis, Calidris acuminate and Limosa limosa but the population size of shorebird winter migrants dominated by Calidris alpine was still larger than the former. (6) Late May to mid-July was the breeding season of all egrets, summer migrants of gulls and several species of shorebirds. Our surveys show that interaction among species is possibly an important determinant of community composition of shorebirds and wintering ducks during the migration season. It may be the geographical position and community composition of migrant shorebirds across Hangzhou Bay that mean during the northward migration there are far more shorebirds than during the southward migration.
This study cloned the hemoglobin α1 from the marine teleost, the half-smooth tongue sole (Cynoglossus semilaevis), and then examined its expression under hypoxia exposure. The full-length of CsHb-α1 (594 bp) cDNA contains an open reading frame encoding 144 amino acids. Sequence analysis shows that the predicted CsHb-α1 amino acids shares high identities with that of other species. Real-time PCR showed that CsHb-α1 was highly expressed in the heart, liver, spleen, kidney and blood. Five to 120 min esposure and long-term (36 h) exposure to hypoxia (1.0 mg/L) significantly increased CsHb-α1 mRNA expression in most tissues compared to those fish held in normoxic conditions (dissolved oxygen (DO): 6.2 mg/L). These results suggested that the up-regulation of Hb-α1 is an important component for adaptation of half-smooth tongue sole to short-term hypoxia.
The PI3K/Akt signal transduction pathway plays an important role in pre-implantation embryonic development. The tumor suppressor gene PTEN negatively regulates the PI3K/Akt pathway. Although PI3K is constitutively activated during pre-implantation embryonic development, currently no evidence shows the presence and possible involvement of PTEN in early embryo development. We investigated the expression of PTEN protein in germinal vesicle (GV) stage oocytes as well as in pre-implantation embryos. The activated form of PTEN was distributed in the peripheral of GV oocytes and compact morula. Treatment of GV oocytes with PTEN inhibitor bpV(pic) did not affect the maturation of the oocyte, but significantly impaired embryonic development. Thus, our study suggests the necessary role of PTEN in pre-implantation embryonic development.
During conjugation of Paramecium caudatum, nuclear events occur in a scheduled program. Morphological studies on nuclear behavior during conjugation of P. caudatum have been performed since the end of the 19th century. Here we report on new details concerning the conjugation of P. caudatum through the staining of conjugating cells with protargol, carbol fuchsin solution, Hoechst 33342 and immunofluorescence labeling with monoclonal antibody of anti-α tubulin. 1) The crescent nucleus is a characteristic of the meiotic prophase of P. caudatum, has an unstained area. We stained this area with protargol, which was separated from the chromatin area and was not detected by the other stainings. 2) In regards to the four meiotic products, it has long been considered that only one product enters the paroral cone region (PC) and survives after meiosis. However, our protargol and immunofluorescence labeling results indicated that PC entrance of the meiotic product happened before the completion of meiosis instead of after. 3) In our previous study, protargol staining indicated the presence of a swollen structure around the central part of the “U” and “V” shaped spindles connecting the two types of prospective pronuclei. However, immunofluorescence labeling with anti-α tubulin antibodies gave a different image from protargol. All these observations form the basis for further studies of their molecular mechanisms.
The embryonic development of Portunus pelagicus was studied in under laboratory conditions at a water temperature of 25-26 ℃, salinity of 30, and pH of 7.8-8.4. The embryogenesis of Portunus pelagicus was divided into six stages: cleavage, blastula, gastrula, nauplius, metanauplius, and protozoea. Embryogenesis lasted about 300 h post spawning. Eggs began superficial cleavage about 28 h after spawning when the nucleus appeared at the surface of the egg till the egg divided into 16 cells. The blastula stage was observed about 40 h post spawning and gastrula stage appeared when the presumptive endoderm and other cells near them invaginated. The fourth-stage of embryogenesis, nauplius, was characterized by three pairs of appendages appearing about 90 h post spawning, while metanauplius, the fifth-stage of embryogenesis, was characterized by five pairs of appendages, which appeared about 110 h post spawning. The sixth stage of embryogenesis was protozoea, which was characterized by seven pairs of appendages appearing about 140 h post spawning. The compound eye, heart and pigment cells were also found in the protozoea stage. After the natatory seta formed on the top of maxilliped, the protozoea developed into the zoea at the time of hatching (about 300 h post spawning).
To investigate the relationship between structure and function of the deferens ducts in the Chinese rat snake (Zaocys dhumnades), morphological changes within an annual cycle were observed by routine histological techniques. Also, the correlation of androgen receptor (AR), estrogen receptor (ER), progesterone receptor (PR) and aromatase (Ar) expressions in the vas deferens and testis were studied immunohistochemically. To confirm that the sperm and the spherical structure existed in deferens ducts, we also used routine histological technique observed deferens ducts in the Striped-tailed rat-snake (Elaphe taeniura), Red-banded snake (Dinodon rufozonatum), and Tiger-spotted neck-troughed snake (Rhabdophis tigrina lateralis). The results showed that the deferens ducts of the Chinese Rat Snake were composed of efferent duct, epididymal duct and vas deferens. Efferent duct contained sperm from August-October, and the sperm were observed in the epididymal duct from August-the following January. Throughout the year (except July) a large number of sperm were present in the vas deferens where a previously unreported spherical structure formed by spermatids was observed, which showed no significant differences in the IOD values of AR-, ER-, PR- and Ar-immunoreactivities. Since the spermatids in the spherical structure were undergoing spermatogenesis and this phenomenon also existed in the Striped-tailed rat-snake and Red-banded snake, the term, seminiferous spherule, was named for this spherical structure This study demonstrated that the testis was the main site for snake spermiogenesis, and the seminiferous spherule in vas deferens was the other Both the epididymis and vas deferens stored sperm; however, the vas deferens was the main organ for sperm storage.
To interfere with the drug-cue memory processes of addicts such as reconsolidation by the administration of the β-adrenergic receptor (β-AR) of norepinephrine (NE) antagonist propranolol (PRO) has become a potential therapy in the future to decrease or inhibit relapse. However, the relationship between PRO and the acquisition or retrieval of morphine-cue memory is not clear.This study examined the effects of PRO on the acquisition and retrieval of memories in morphine-induced conditioned place preference (CPP) mice model. We found that during memory acquisition period, PRO had no effects on the expression and extinction of morphine-CPP, which suggests that the β-AR was irrelevant to the CPP memory acqusition. However, during memoery retrival period, although PRO did not affect the expression of CPP, but it delayed the occurrence of CPP extinction, which indicates that PRO has an inhibit effect on CPP memery extinction, and β-AR plays an important role in modulating the extinction of morphine-CPP. Our study further improved the relationship between drug addiction and β-AR, and proposed a new theory to help developing potential therapy to cure addiction and other neuropsychiatric disorders.
The western black crested gibbon (Nomascus concolor) is mainly distributed in Yunnan, China. Ailao Mountain is located in central Yunnan and divided into three prefectures and six counties. This mountain forms the principle distribution range for western black crested gibbon; however, there are no published data on the gibbon population inhabiting the Xinping administrative. Take the interview results conducted in 2007 and 2009 with local people as the reference, this study conducted an extensive field survey covering all possible habitats from November 2009 to January 2010 using call surveys. Among the one hundred and twenty-four gibbon groups which were confirmed across the Ailao Mountain, the largest known population of western black crested gibbons yet, 85 groups inhabit the national nature reserve and adjacent national forest, 30 groups inhabit the provincial nature reserve and nine groups inhabit the collective forest located outside the reserve and national forest. We found that the western black crested gibbons here have a patchy distribution pattern and occur at higher densities in certain areas. Moreover, the population distribution density and elevation gradient distribution decline from north to south. The results also demonstrated the importance of Ailao Montain in the western black crested gibbon protection.
The bent-toed gecko (Cyrtodactylus wayakonei Nguyen, Kingsada, Rösler, Auer and Ziegler, 2010) has been recorded for the first time in China. Here, we provide descriptions of specimens from Yunnan, China. This species was distinguished from all congeners by the following characteristics: 7–8 supralabials; 9–10 infralabials; dorsal tubercles smooth to slightly keeled; 17–19 rows of dorsal tubercles; 6–8 precloacal pores in both sexes; femoral scales not enlarged; no femoral pores; subcaudals somewhat enlarged and broadened; and tail tubercles flat and smooth.
There is a high proportion of parthenogenesis in insecta, and the parthenogenetic potential of insects is an important but often ignored threaten factor for the agricultural and forestry production. The maintenance of parthenogenetic species is a puzzling issue in evolutionary biology. In recent years, although the cellular mechanisms during parthenogenesis in some species have been well studied, the underlying genetic mechanisms that cause the switch from sexual reproduction to parthenogenesis have not been defined. While, understanding the genetic mechanism and evolutionary significance of the origin of parthenogenetic insects is crucial for preventing the pests in agricultural and forestry production. Here we summarized recent studies aimed at identifying the underlying genetic mechanism of parthenogenesis in insects, and briefly discussed its potential application in this filed.