爬行动物MHC基因研究进展

主要组织相容性复合体(MHC)是有颌脊椎动物中发现的编码免疫球蛋白受体的高度多态的基因群,因其在免疫系统中的重要作用而备受关注。脊椎动物不同支系间MHC的结构和演化差异较大。尽管MHC基因特征在哺乳类、鸟类、两栖类和鱼类中已被较好地描述,但对爬行动物MHC的了解仍较少。鉴于爬行动物对于理解MHC基因的演化占据很重要的系统发育位置,研究其MHC具有重要意义。本文就近年来爬行动物MHC的分子结构、多态性维持机制、功能和主要应用的研究现状进行了系统地回顾和总结,并展望了其研究前景。     

Proliferation, neurogenesis and regeneration in the non-mammalian vertebrate brain

Post-embryonic neurogenesis is a fundamental feature of the vertebrate brain. However, the level of adult neurogenesis decreases significantly with phylogeny. In the first part of this review, a comparative analysis of adult neurogenesis and its putative roles in vertebrates are discussed. Adult neurogenesis in mammals is restricted to two telencephalic constitutively active zones. On the contrary, non-mammalian vertebrates display a considerable amount of adult neurogenesis in many brain regions. The phylogenetic differences in adult neurogenesis are poorly understood. However, a common feature of vertebrates (fish, amphibians and reptiles) that display a widespread adult neurogenesis is the substantial post-embryonic brain growth in contrast to birds and mammals. It is probable that the adult neurogenesis in fish, frogs and reptiles is related to the coordinated growth of sensory systems and corresponding sensory brain regions. Likewise, neurons are substantially added to the olfactory bulb in smell-oriented mammals in contrast to more visually oriented primates and songbirds, where much fewer neurons are added to the olfactory bulb. The second part of this review focuses on the differences in brain plasticity and regeneration in vertebrates. Interestingly, several recent studies show that neurogenesis is suppressed in the adult mammalian brain. In mammals, neurogenesis can be induced in the constitutively neurogenic brain regions as well as ectopically in response to injury, disease or experimental manipulations. Furthermore, multipotent progenitor cells can be isolated and differentiated in vitro from several otherwise silent regions of the mammalian brain. This indicates that the potential to recruit or generate neurons in non-neurogenic brain areas is not completely lost in mammals. The level of adult neurogenesis in vertebrates correlates with the capacity to regenerate injury, for example fish and amphibians exhibit the most widespread adult neurogenesis and also the greatest capacity to regenerate central nervous system injuries. Studying these phenomena in non-mammalian vertebrates may greatly increase our understanding of the mechanisms underlying regeneration and adult neurogenesis. Understanding mechanisms that regulate endogenous proliferation and neurogenic permissiveness in the adult brain is of great significance in therapeutical approaches for brain injury and disease.     

Food habits of three carnivore species (Viverricula indica, Herpestes urva, and Melogale moschata) in Fushan Forest, northern Taiwan

The food habits and degrees of dietary overlap of lesser oriental civet ( Viverricula indica ), crab-eating mongoose ( Herpestes urva ), and ferret badger ( Melogale moschata ) inhabiting the Fushan Forest, northern Taiwan, were studied using faecal analysis between February 1993 and June 1994. Laboratory analysis of 154 civet faeces, and 174 mongoose faeces showed that both species fed on a wide variety of food items, including mammals, birds, reptiles, amphibians, fish, crustaceans, insects, oligochaetes, gastropods, chilopods, arachnids, and plants. Insects, oligochaetes, plants, and mammals were the four most important food items in the civets' diet, whereas crustaceans, insects, amphibians, and reptiles were the four most important food items consumed by mongooses. Amphibians were the only vertebrates, together with invertebrates and plants, found in the 64 ferret badger faeces we analysed, and oligochaetes, insects, and amphibians were the most important food items consumed by ferret badgers. The diversity of diet was highest in the mongoose, followed by the civet, and was lowest in the ferret badger.
The degree of dietary overlap was greatest between the civet and the ferret badger, followed by that of the civet and mongoose. The mongoose and ferret badger had the lowest degree of dietary overlap. However, the degree of dietary overlap varied in different seasons. Invertebrates were the most important food source for the carnivores in Fushan Forest.     

Evolutionary diversity of reverse (R) fluorescent chromosome bands in vertebrates

Mitotic chromosomes, interphase cell nuclei, and male meiosis of 41 species representing all vertebrate classes were analyzed with distamycin A/mithramycin counterstaining. The purpose of the study was to recognize differences and common characteristics in the reverse (R) fluorescent banding patterns in the chromosomes of vertebrate species at various stages of evolution. In contrast to the warm-blooded mammals and birds, the euchromatic segments in the chromosomes of most reptiles, amphibians, and fishes contain no multiple fluorescent R-bands. This is thought to be due to the absence of the long homogeneous regions (isochores) in the DNA of the cold-blooded vertebrates. Distamycin A/mithramycin banding specifically reveals the GC-rich constitutive heterochromatin in all vertebrates. In most of the vertebrate chromosomes examined, the heterochromatic regions have opposite staining properties with mithramycin and quinacrine. Mithramycin labels the nucleolus organizer regions very brightly in the karyotypes of fishes, amphibians, reptiles and birds, but not of mammals. The lack of mithramycin fluorescence at the nucleolus organizer regions of mammals is attributed to the relatively low level of redundancy of the GC-rich ribosomal DNA in their genomes. Studies on the various meiotic stages of the cold-blooded vertebrates show that the mithramycin labeling of the nucleolus organizers is independent of their state of activity. This can be confirmed by mithramycin fluorescence at the nucleoli of actinomycintreated cells.Dedicated to the memory of Professor Dr. Hans Bauer     

Partitioning sources of variation in vertebrate species richness

Aim To explore biogeographic patterns of terrestrial vertebrates in Maine, USA using techniques that would describe local and spatial correlations with the environment. Location Maine, USA. Methods We delineated the ranges within Maine (86,156 km²) of 275 species using literature and expert review. Ranges were combined into species richness maps, and compared to geomorphology, climate, and woody plant distributions. Methods were adapted that compared richness of all vertebrate classes to each environmental correlate, rather than assessing a single explanatory theory. We partitioned variation in species richness into components using tree and multiple linear regression. Methods were used that allowed for useful comparisons between tree and linear regression results. For both methods we partitioned variation into broad‐scale (spatially autocorrelated) and fine‐scale (spatially uncorrelated) explained and unexplained components. By partitioning variance, and using both tree and linear regression in analyses, we explored the degree of variation in species richness for each vertebrate group that could be explained by the relative contribution of each environmental variable. Results In tree regression, climate variation explained richness better (92% of mean deviance explained for all species) than woody plant variation (87%) and geomorphology (86%). Reptiles were highly correlated with environmental variation (93%), followed by mammals, amphibians, and birds (each with 84–82% deviance explained). In multiple linear regression, climate was most closely associated with total vertebrate richness (78%), followed by woody plants (67%) and geomorphology (56%). Again, reptiles were closely correlated with the environment (95%), followed by mammals (73%), amphibians (63%) and birds (57%). Main conclusions Comparing variation explained using tree and multiple linear regression quantified the importance of nonlinear relationships and local interactions between species richness and environmental variation, identifying the importance of linear relationships between reptiles and the environment, and nonlinear relationships between birds and woody plants, for example. Conservation planners should capture climatic variation in broad‐scale designs; temperatures may shift during climate change, but the underlying correlations between the environment and species richness will presumably remain.     

Evolutionary physiology by data of publications for 1965–2005

Evolutionary physiology as independent direction of physiology was formed in the XX century and was rapidly developing in its second half. To evaluate some tendencies of this process, we analyzed publications in Journal of Evolutionary Biochemistry and Physiology, one of the leading specialized periodicals on this problem. Analysis of works published for 4 decades has shown that the majority of papers deals with study of evolution of function of the nervous system (40–60 papers per year), less papers concern study of functions of sensory and visceral systems (20–30 per year). Among the used method, the most widely spread is the comparative-physiological method. By the end of the 1990s the number of works with use of methods of embryophysiology decreased. In the performed studies, predominant are physiological methods. Use of biochemical methods decreased, while of methods of molecular biology increased. The most often used objects of studies were mammals. By the end of the XX—beginning of the XXI century, in the greater number of papers the object of study has become human, while the number of publications in which experiments were performed on amphibians, reptiles, and birds decreased. More than a half of all works were carried out in St. Petersburg (Leningrad); the number of papers submitted from Moscow institutions gradually decreased, but the number of works from regions of Russia rose. Most studies were performed at institutes of the Russian Academy of Sciences and universities, while the number of papers from institutes of the Russian Academy of Medical Sciences decreased. For the last few years, several generalizations on evolution of functions and functional evolution have been formulated; handbooks and monographs on problems of evolutional physiology have been published.     

New host records of the nematode Gnathostoma sp. in Mexico

Gnathostomiasis is an emerging zoonosis in Mexico. However, for most endemic zones, the source of human infection has not been established. During 2000-2003, we investigated 2168 vertebrates (2047 fish, 31 amphibians, 4 reptiles, 19 birds and 67 mammals) from 39 localities distributed in nine states. We registered 7 vertebrate species as new hosts for Gnathostoma, and 22 new locality records for this nematode.     

Relationships between species richness of vascular plants and terrestrial vertebrates in China: analyses based on data of nature reserves

The relationship between plant diversity and animal diversity on a broadscale and its mechanisms are uncertain. In this study, we explored this relationship and its possible mechanisms using data from 186 nature reserves across China on species richness of vascular plants and terrestrial vertebrates, and climatic and topographical variables. We found significant positive correlations between species richness in almost all taxa of vascular plants and terrestrial vertebrates. Multiple regression analyses indicated that plant richness was a significant predictor of richness patterns for terrestrial vertebrates (except birds), suggesting that a causal association may exist between plant diversity and vertebrate diversity in China. The mechanisms for the relationships between species richness of plants and animals are probably dependent on vertebrate groups. For mammals (endothermic vertebrates), this relationship probably represents the integrated effects of plants on animals through trophic links (i.e. providing foods) and non-trophic interactions (i.e. supplying habitats), whereas for amphibians and reptiles (ectothermic vertebrates), this may be a result of the non-trophic links, such as the effects of plants on the resources that amphibians and reptiles require.     

Mortality of vertebrates on a road crossing the Biebrza Valley (NE Poland)

Mortality of vertebrates was monitored on a local road running across Poland’s Biebrza River Valley during 2 years (August 2005–July 2006). On the basis of distance from the river and surrounding habitats, the road (of total length 2,510 m) was divided into three stretches. The road was monitored on foot by two people every month, over a few consecutive days. A total of 1,892 road kills representing at least 47 species were found. Of these, 90.7% were amphibians, 4.2% mammals, 3.1% birds and 2.0% reptiles. Most (70%) of the amphibians were anurans, with the common toad, common frog and moor frog among them together accounting for 82% of the total. Mortality among amphibians differed between months, most anurans dying in May and August, while a majority of Urodela are lost in October. The peaks in mortality were connected with the migration of adult amphibians in spring and juveniles in summer and autumn. The number of amphibians killed was greatest on the (wettest) stretch adjacent to the river and decreased with distance from it. Mortality among birds was highest in July—probably in association with the dispersal of young individuals. Among recorded mammalian road kills, there was a prevalence of small rodents (mainly voles) and insectivores (mainly shrews). Medium-sized mammals were found only accidentally. Mortality in general was conditioned by the number of anurans killed.     

Evolution of oestrogen functions in vertebrates

Steroidal oestrogens have been isolated from marine and terrestrial animals representative of all major classes of vertebrates including fish, amphibians, reptiles, birds and mammals. In general, oestrogens are responsible for most features characteristic of the female sex of a species, such as metabolic, behavioural and morphological changes during the stages of reproduction; they also support several processes in males. The evolution of the hormonal system always involves both the ligand and its sites of interaction. In the case of oestrogens, the steroid producing enzymes, mainly the aromatase complex, and the oestrogen receptor belong together within their co-evolution. The finding of oestrogenic steroids, the more recent identification of aromatase and receptor genes and their expression fit together, thereby confirming the importance for all vertebrates. Within the present paper, the evolution of the physiological functions of oestrogens from oviparous vertebrates to Eutherian mammals, oestrogen biosynthesis, metabolization and signalling pathways will be reviewed in detail.     

New monoclonal antibodies against gastric gland mucous cell-type mucins: a comparative immunohistochemical study

 The immunohistochemical reactivity of monoclonal antibodies raised against rat and pig gastric mucins (HIK1083, PGM36, and PGM37) was investigated in normal gastrointestinal tracts obtained from fish, amphibians, reptiles, birds, and mammals (including humans). These monoclonal antibodies exhibited highly selective reactivity with class III mucins, as identified by paradoxical concanavalin A stain, in the gastrointestinal tract of vertebrates. All three monoclonal antibodies reacted with the mucous neck cells and pyloric gland cells of amphibians, reptiles and mammals, the cardiac glands of reptiles and mammals, and Brunner’s glands of mammls. The deep crypt secretory cells of the rat colon and certain goblet-type cells deep in crypts in the pig colon differed from the above pattern only in that they did not show immunoreactivity with monoclonal antibody PGM36. These data suggest that the development of class III mucin is a fundamental evolutionary characteristic of vertebrate gastric mucins. These monoclonal antibodies should prove useful for the investigation of cell differentiation among gastrointestinal mucous cells and for the biochemical analysis of gastrointestinal mucins in different species. Accepted: 17 February 1998     

Body cavities in fishes

Four types of body cavity arrangement were found in 20 species of fish (see Materials and Methods). The body cavities of fishes were also compared with those of mammals and birds. It was concluded that higher vertebrates utilized only the Tinca type for their evolution, while the other types were dead-end evolutionary forms which terminated at fish level, or possibly with amphibians and reptiles. The necessary research in these groups still remains to be done.     

Badger Meles meles diet: a review of literature from the former Soviet Union

We review 69 studies of the diet of Badgers Meles meles L. in the former Soviet Union, using information from 58 Russian-language papers. Animal foods occurred more frequently in the diet than vegetal foods and constituted, on average, 62% of all intake by volume. The most important individual food categories were insects (30% by volume) and small mammals (20% by volume), which appear to be staple foods of Badgers over virtually the whole of the former Soviet Union. Earthworms were mentioned in only a few reports and never exceeded 5% of the diet by volume. Other animal foods included birds, reptiles, amphibians, fish, molluscs and carrion. Fruits were seasonally important in some areas while roots, tubers, bulbs, cereals and nuts were also eaten; but in general, the Soviet literature lacks detailed information about vegetal foods. Many authors comment on seasonal variation in the diet and there was statistically significant seasonal variation in the frequency with which small mammals, reptiles, insects and vegetal foods were eaten. No largescale geographical trends were apparent in the composition of the diet, but foods which were of minor importance overall, such as reptiles, amphibians and molluscs, were sometimes eaten with high frequency in particular localities. The results support the view that Badgers are opportunistic, generalist foragers, with a preference for animal foods when these are available.     

Germline development in amniotes: A paradigm shift in primordial germ cell specification

In the field of germline development in amniote vertebrates, primordial germ cell (PGC) specification in birds and reptiles remains controversial. Avians are believed to adopt a predetermination or maternal specification mode of PGC formation, contrary to an inductive mode employed by mammals and, supposedly, reptiles. Here, we revisit and review some key aspects of PGC development that channelled the current subdivision, and challenge the position of birds and reptiles as well as the ‘binary’ evolutionary model of PGC development in vertebrates. We propose an alternative view on PGC specification where germ plasm plays a role in laying the foundation for the formation of PGC precursors (pPGC), but not necessarily of PGCs. Moreover, inductive mechanisms may be necessary for the transition from pPGCs to PGCs. Within this framework, the implementation of data from birds and reptiles could provide new insights on the evolution of PGC specification in amniotes.     

Primate origins and the evolution of angiosperms

Traditionally, the morphological traits of primates were assumed to be adaptations to an arboreal way of life. However, Cartmill [1972] pointed out that a number of morphological traits characteristic of primates are not found in many other arboreal mammals. He contends that orbital convergence and grasping extremities indicate that the initial divergence of primates involved visual predation on insects in the lower canopy and undergrowth of the tropical forest. However, recent research on nocturnal primates does not support the visually-oriented predation theory. Although insects were most likely important components of the diets of the earliest euprimates, it is argued here that visual predation was not the major impetus for the evolution of the adaptive traits of primates. Recent paleobotanical research has yielded evidence that a major evolutionary event occurred during the Eocene, involving the angiosperms and their dispersal agents. As a result of long-term diffuse coevolutionary interactions with flowering plants, modern primates, bats, and plant-feeding birds all first arose around the Paleocene-Eocene boundary and became the major seed dispersers of modern tropical flora during the Eocene. Thus, it is suggested here that the multitude of resources available on the terminal branches of the newly evolved angiosperm, rain forest trees led to the morphological adaptations of primates of modern aspect.     

The diet of feral cats on islands: a review and a call for more studies

Cats are among the most successful and damaging invaders on islands and a significant driver of extinction and endangerment. Better understanding of their ecology can improve effective management actions such as eradication. We reviewed 72 studies of insular feral cat diet from 40 islands worldwide. Cats fed on a wide range of species from large birds and medium sized mammals to small insects with at least 248 species consumed (27 mammals, 113 birds, 34 reptiles, 3 amphibians, 2 fish and 69 invertebrates). Three mammals, 29 birds and 3 reptiles recorded in the diet of cats are listed as threatened by the IUCN. However, a few species of introduced mammals were the most frequent prey, and on almost all islands mammals and birds contributed most of the daily food intake. Latitude was positively correlated with the predation of rabbits and negatively with the predation of reptiles and invertebrates. Distance from landmass was positively correlated with predation on birds and negatively correlated with the predation of reptiles. The broad range of taxa consumed by feral cats on islands suggests that they have the potential to impact almost any native species, even the smallest ones under several grams, that lack behavioral, morphological or life history adaptations to mammalian predators. Insular feral cat??s reliance on introduced mammals, which evolved with cat predation, suggests that on many islands, populations of native species have already been reduced.     

Seasonal and sex-specific prey composition of black-footed catsFelis nigripes

During a 6-year field study on the game farm ‘Benfontein’ in the central Republic of South Africa 1725 prey items were observed consumed by 17 free-ranging habituated black-footed catsFelis nigripes Burchell, 1824. Average prey size was 24.1 g. Eight males fed on significantly larger prey (27.9 g) than 9 females (20.8 g). Fifty-four prey species were classified by their average mass into 8 different size classes, 3 for mammals, 3 for birds, 1 for amphibians/reptiles, and 1 for invertebrates. Small mammals (5–40 g) constituted the most important prey class (39%) of total prey biomass followed by larger mammals (>100 g; 17%) and small birds (<40 g; 16%). Mammals and birds pooled comprised 72% and 26% of total prey biomass, respectively, whereas invertebrates and amphibians/reptiles combined constituted just 2% of total prey mass consumed. Three seasons of 4-months duration were recognized. Heterotherm prey items were unavailable during winter, when larger birds and mammals (> 100 g) were mainly consumed. Small rodents like the large-eared mouseMalacothrix typica, captured 595 times by both sexes, were particularly important during the reproductive season for females with kittens. Male black-footed cats showed less variation between prey size classes consumed among climatic seasons. This sex-specific difference in prey size consumption may help to reduce intra-specific competition.     

短尾蝮蛇IRF-2基因的克隆和特征分析

报道了短尾蝮蛇Gloydius brevicaudus干扰素调节因子2基因(IRF-2)的克隆和cDNA全序列测定分析.目前除在爬行类外,IRF-2基因在大部分的脊椎动物如鱼类、两栖类、鸟类和哺乳类都有报道.为了获得爬行类IRF-2基因的全序列,从短尾蝮蛇的肾、脾、肝和肠4种组织中使用Trizol试剂盒提取了总RNA.从已知的IRF-2基因序列比对设计了简并引物来扩增保守片段.最后使用RACE方法得到IRF-2的cDNA全序列.结果 显示短尾蝮蛇的IRF-2基因开放阅读框包含有978个核苷酸,编码326个氨基酸,其3′UTR包含137个核苷酸.与脊椎动物其他四足动物序列比对分析还发现,短尾蝮蛇的IRF-2基因和推导的氨基酸序列都非常保守,与大部分四足动物的IRF-2相似.从其氨基酸序列中可以辨别出DBD、IDA2和transactivating domain等大部分元件和阻遏模体.     

Global comparisons of beta diversity among mammals, birds, reptiles, and amphibians across spatial scales and taxonomic ranks

Beta diversity is the change in species composition among areas in a geographic region. The proportion of species shared between two areas often decreases when the distance separating them increases, leading to an increase in beta diversity. This study compares beta diversity among four classes of terrestrial vertebrates （mammals, birds, reptiles, and amphibians） at both regional （biogeographic realm） and global extents, using the same sets of faunal sample units for all four groups in each comparison. Beta diversity is lower for the two endothermic taxa （birds and mammals） than for the two ectothermic taxa （reptiles and amphibians） in all six biogeographic realms examined. When the four taxa in the six biogeographic realms are combined, beta diversity at the species rank is higher than that of the genus rank by a factor of 1.24, and is higher than that of the family rank by a factor of 1.85. The ratio of beta diversity at the genus rank to that at the family rank is 1.50. Beta diversity is slightly higher for ecoregions of 5000-99,999 km^2 than for ecoregions of 100,000-5,000,000 km^2.     

Diets of Ocelots (Leopardus pardalis), Margays (L. wiedii), and Oncillas (L. tigrinus) in the Atlantic Rainforest in Southeast Brazil

Felids play an important role in structuring the prey community, and thus in the dynamics of the plant community in tropical forests. The diets of three species of small cats, Leopardus pardalis (ocelot), L. wiedii (margay), and L. tigrinus (oncilla) were investigated by analysis of scats and regurgitations during a one-year study at Parque Estadual Serra do Mar, Núcleo Santa Virgínia, southeastern Brazil. Small non-volant mammals were the most frequent prey in all the diets. The diets of the three cats were similar but although they consumed the same prey items, they showed differential use of them. Ocelots consumed more reptiles than the other species, oncillas preyed on birds and arboreal marsupials, whereas margays were generalists.