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2012年  第33卷  第4期

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Understanding large-scale geographic patterns of species richness as well its underlying mechanisms are among the most significant objectives of macroecology and biogeography. The ecological hypothesis is one of the most accepted explanations of this mechanism. Here, we studied the geographic patterns of snakes and investigated the relationships between species richness and ecological factors in China at a spatial resolution of 100 km×100 km. We obtained the eigenvector-based spatial filters by Principal Coordinates Neighbor Matrices, and then analyzed ecological factors by multiple regression analysis. The results indicated several things: (1) species richness of snakes showed multi-peak patterns along both the latitudinal and longitudinal gradient. The areas of highest richness of snake are tropics and subtropical areas of Oriental realm in China while the areas of lowest richness are Qinghai-Tibet Plateau, the grasslands and deserts in northern China, Yangtze-Huai Plain, Two-lake Plain, and the Poyang-lake Plain; (2) results of multiple regression analysis explained a total of 56.5% variance in snake richness. Among ecological factors used to explore the species richness patterns, we found the best factors were the normalized difference vegetation index, precipitation in the coldest quarter and temperature annual range ; (3) our results indicated that the model based on the significant variables that (P<0.05) uses a combination of normalized difference vegetation index, precipitation of coldest quarterand temperature annual range is the most parsimonious model for explaining the mechanism of snake richness in China. This finding demonstrates that different ecological factors work together to affect the geographic distribution of snakes in China. Studying the mechanisms that underlie these geographic patterns are complex, so we must carefully consider the choice of impact-factors and the influence of human activities.
Using simultaneous land surveys, we monitored the population size and spatial distribution of wintering Siberian cranes at 64 lakes around Poyang Lake between 1998 and 2010. The results showed that 46 lakes were inhabited by wintering cranes, and in 25 of those, the number of wintering cranes accounted for more than 1% of the Siberian cranes’ global population. The lakes where over 40.0% of the global population, e.g. 1 280 individuals, included Dachahu Lake in Jiujiang region, and Banghu Lake and Candouhu Lake in the Poyang Lake Nature Reserve. The average yearly population of the wintering Siberian crane in the Poyang lakes was 3 108±849, with the maximum of 4 004 individuals in winter 2002. On the whole, there was no drastic fluctuation, but population numbers have shown considerable fluctuation since 2003. We also found the Poyang Lake Nature Reserve was the major wintering area of the Siberian crane, with over 60% of Siberian cranes wintering in the reserve since 2002 (except in 2006). Most of the inhabited lakes are covered in existing nature reserves, though some lakes outside the reserve were also considerably used by Siberian cranes.
This work used Immunohistochemistry to examine the expression of myelin basic protein and accumulation of oligodendrocytes in Pchdaknockout and control littermate mice. Data showed that in Pchda knockout mice, Myelin proteins decrease in the central nervous systemand mature oligodendrocytes in the cerebellum also decrease. Furthermore, deletion of the Pcdha cluster does not cause any change to the axons and astrocytes in quantification of relative marker proteins. These findings suggest that the Pcdha cluster may be required for myelination and oligodendrite development of the brain in mice, and that Pcdha cluster may play a key role in the development of the central nervous system.
To investigate the effects and possible mechanisms of resistin on hepatic fibrosis in non-alcoholic fatty liver disease, this review used an in vivo model utilizing Wistar rats with a high fat diet. Recombinant resistin was selected to play role in hepatic stellate cells in the HSC-T6 cell line. We observed the degrees of hepatic ?brosis, measured the levels of Liver fibrosis spectrum and detected expression levels of resistin mRNA and protein in liver tissue as well as the expression levels of TGFβ-1 and TNF-α mRNA in HSC-T6. The results showed that expression of resistin in rat liver tissue and the degree of hepatic fibrosis increased over time with a high fat diet. Along with the increased concentration of resistin and levels of fibrosis index, TGFβ-1and TNF-α also increased in HSC-T6 cells. Compared with the control group, significant differences were found between each group, suggesting resistin by proinflammatory cytokine TNF-α and TGF-β1 induced the occurrence and development of NAFLD in hepatic fibrosis.
Explaining the evolution of cooperation remains one of the important problems in both biology and social science. Classical theories mainly based on an assumption that cooperative players are symmetrically interacted. However, almost all the well-studied systems showed that cooperative players are in fact asymmetrically interacted and that asymmetric interaction might greatly affect cooperation behavior of the involved players. Considering the asymmetric interaction and the selection pressure of resources, we present a model that possesses four strategies: strength- cooperation (SC), strength-defection (SD), weakness-cooperation (WC) and weakness-defection (WD). Combining evolutionary game theory with dynamical stability theory, we find that the evolutionary results closely depend on the asymmetric interaction and selection pressure of resources as well as cost-to-benefit ratio of conflict. When the common resources are plentiful, the cost-to-benefit ratio of conflict is negatively correlated with the probability of SC, while it is positively correlated with the probability of SD and WD. With increasing the strength ratio between the strong and weak players, the proportion of SC and SD will increase, while the proportion of WD will reduce. The model developed here has intrinsically integrated Boxed Pigs game and Hawk-Dove game. When the common resource is at shortage, the Boxed Pigs game will transform into Hawk-Dove game under the increase of the strength ratio between the strong and weak players.
We sought to experimentally verify if testis specific serine/threonine kinases (Tssks) play a role in spermatogenesis and/or the regulation of sperm function. Purified Tssk proteins were obtained based on cloning and expression of mouse Tssk1 and Tssk2. Tssk1 and Tssk2 were detected in mature mouse and human sperm by western blotting. Immunofluorescence indicated that Tssk1 is distributed in the acrosome and the entire flagellum of mouse sperm while Tssk2 was mainly distributed in post-acrosomal region. There was no alteration in the distribution pattern of Tssk1 and Tssk2 in non-capacitated and capacitated sperm. Tssk2 distribution remained unchanged after induced acrosome reaction but no signals were detected in the acrosome for Tssk1, which was present before the acrosome reaction, though signals in flagellum were undisturbed. In human sperm, Tssk1 was found in neck and flagellum while Tssk2 was found in the equatorial region. Our results suggest Tssk1 and/or Tssk2 do play an important role(s) in the regulation of sperm function.
In amphioxus, we found a mesoderm related gene, tropomyosin,which encodes a protein comprising 284 amino acid residues, sharing high identities with other known Tropomyosin proteins both in vertebrates and invertebrates. Phylogenetically, amphioxus Tropomyosin fell outside the invertebrate clade and was at the base of the vertebrate protein family clade, indicating that it may represent an independent branch. From the early neurula to the larva stage, whole-mount in situ hybridization and histological sections found transcripts of amphioxus tropomyosin gene. Weak tropomyosin expression was first detected in the wall of the archenteron at about 10 hours-post-fertilization neurula stage, while intense expression was revealed in the differentiating presumptive notochord and the muscle. Transcripts of tropomyosin were then expressed in the formed notochord and somites. Gene expression seemed to continue in these developing organs throughout the neurular stages and remained till 72-hours, during the early larval stages. In situ study still showed tropomyosin was also expressed in the neural tube, hepatic diverticulum, notochord and the spaces between myotomes in adult amphioxus. Our results indicated that tropomyosin may play an important role in both embryonic development and adult life.
The tubulin beta III (TUBB3) gene encodes a class III member of the beta tubulin protein family that is primarily expressed in neurons and is considered to play a critical role in proper axon guidance and maintenance. This protein is generally used as a specific marker of neurons in the central nervous system. We obtained the full length cDNA sequence of TUBB3 by using the RACE method based on the EST fragment from the brain and spinal cord cDNA library of Gekko japonicus. We further investigated the multi-tissue expression pattern by RT-PCR and identified one transcript of TUBB3 about 1.8 kb in the central nervous system of Gekko japonicus by Northern blotting. The completed cDNA of gecko TUBB3 is 1 790 bp with an open reading frame of 1 350 bp, encoding a 450 amino-acid protein. The recombinant plasmid of pET-32a-TUBB3 was constructed and induced to express His-tagged TUBB3 protein in prokaryotic BL21 cells. The purified TUBB3 protein was then used to immunize rabbits to generate polyclonal antisera. The titer of the antiserum was more than 1:65 536 determined by ELISA. The result of western blotting showed that the TUBB3 antibody could specifically recognize the recombinant TUBB3 protein and endogenous TUBB3 protein. Our findings provide the tools to further understand the TUBB3 gene and investigate the regeneration of the central nervous system in Gekko japonicas.
To elucidate the genetic characteristics of the bovine Inhibin α subunit (INHA) gene, the polymorphisms in exon 1 of INHA and its bilateral sequences were assayed using PCR with direct sequencing in buffalo, gayal and yak. A comparative analysis was conducted by pooled the results in this study with the published data of INHA on some mammals including some bovine species together. A synonymous substitution c.73C>A was identified in exon 1 of INHA for buffalo, which results in identical encoding product in river and swamp buffalo. In gayal, two non-synonymous but same property substitutions in exon 1 of INHA, viz. c.62 C>T and c.187 G>A, were detected, which lead to p. P21L, p. V63M changes in INHA, respectively. In yak, nucleotide substitution c.62C>T, c.129A>G were found in exon 1 of INHA, the former still causes p. P21L substitution and the latter is synonymous. For the sequence of the 5'-flanking region of INHA examined, no SNPs were found within the species, but a substitution, c. -6T>G, was found. The nucleotide in this site in gayal, yak and cattle was c. -6G, whereas in buffalo it was c. -6T. Meanwhile, a 6-bp deletion, namely c. 262+31_262+36delTCTGAC, was found in the intron of buffalo INHA gene. For this deletion, wild types (+/+) account for main part in river buffalo while mutant types (-/-) are predominant in swamp buffalo. This deletion was not found in gayal, yak and cattle, though these all have another deletion in the intron of INHA, c. 262+78_262+79delTG. The results of sequence alignment showed that the substitutions c. 43A and c. 67G in exon 1 of INHA are specific to buffalo, whereas the substitutions c. 173A and c. 255G are exclusive to gayal, yak and cattle, and c. 24C, c. 47G, c. 174T and c. 206T are specific to goat. Furthermore, there are few differences among gayal, yak and cattle, but there relatively great differences between buffalo, goat and other bovine species regarding the sequences of INHA exon 1.
Attempts to understand the degeneration of the eyes in cave fish has largely been explained by either various extents of gradual degeneration, ranging from partial to total loss, observed in various species or by acceleration of loss caused by dark environments. However, neither the theory of biological evolution developed by Charles Darwin nor the neutral theory of molecular evolution formulated by Kimura Motoo adequately explains these phenomena. Recent trends in utilizing multidisciplinary research, however, have yielded better results, helping reveal a more complex picture of the mechanisms of degeneration. Here, we summarize the current progress of the research via morphology and anatomy, development biology, animal behavior science and molecular genetics, and offer some perspectives on the ongoing research into the development and degeneration of eyes in cave fish.
MicroRNAs (miRNAs) are a newly identified class of small regulatory non-coding endogenous RNAs that take part in a series of important processes by regulating gene expression. Recent studies have provided evidence that miRNAs may be involved in nearly all biological and metabolic processes, especially influencing self-renewal and differentiation of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). In this review, we briefly summarize the biological characteristics of miRNAs, the detection technologies, and the role of miRNAs regulation in ESCs and iPSCs to frame a discussion on the future prospects of miRNA research.
Originally grown and produced in southern of Yunnan, China, Pu-erh tea has a long history and carries rich cultural connotations. Consumption of Pu-erh has been thought to possess numerous health benefits including weight-loss, lowering of blood glucose levels, and preventing cardiovascular diseases. Research on humans, rodents, and cell lines have each confirmed that Pu-erh tea indeed displays weight-loss and blood lipid lowering effects. The main bioactive components, such as theabrownin (TB), polysaccharides, polyphenols, and statins, may down-regulate the biosynthesis of fat and up-regulate the oxidation of fat to cut weight and reduce the content of lipids in blood. Here, we summarize current progress on understanding the mechanisms and bioactive components of Pu-erh’s weight-cutting effects as well as highlighting current weaknesses in the field in order to suggest possible solutions for future research on Pu-erh tea.