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2005年  第26卷  第2期

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研究论文
Life-history theory predicts that differences in reproductive effort and residual reproductive value among species should result in differences in the level of risk that parents are willing to tolerate to themselves versus their offspring. Here,we tested the prediction that parental investment decisions were correlated with nest sites by comparing risk - taking behaviour in two species of passerines (small skylark Alauda gulgula and horned lark Eremophila alpestris) in alpine meadow, from 2002 to 2004. We experimentally manipulated predation risk by presenting models and measured the willingness of parents to feed nestlings. The results shown:Response of the horned lark to human intrusion was a significantly stronger than the small skylark;Both species responded to predators by decreasing the length of attendance time,reducing the feeding rate and increasing the length of elapsed time;There was significantly difference between the reproductive behaviour in the small skylark and horned lark in the natural condition,whereas,no difference in the predator condition;Males of both species had lower willingness to tolerate risk to themselves than females. Thus,those passerine species responded to predators by reducing investment in current reproduction and increasing probability of future survival. Our experimental results support the above prediction.
In order to understanding the competitive relationship among predators and planning a conservation program for the wildlife around Beijing, 85 feces samples of carnivores were collected by a strip-sampling method at two scenic spots (Songshan, and Yunmengshan) and one nature reserve (Wulingshan) in 2002, which mainly belonged to Vulpes vulpes and Nyctereutes procyonoides of Canidae, Mustela sibirica and Arctomyx collaris of Mustelidae, and leopard cat (Felis bengalensis) of Felidae. And then the food habits of animals were studied by feces content analysis. The results revealed that the small mammals were the main food and the percentage of occurrence of rodents in the total samples was 82.4%. The second and third orders of foods were plants (54.1%) and birds (31.8%) respectively. But the occurrence rates of big preys of roe deer (Capreolus capreolus) and hare (Lepus capensis) were only 8.2%. The main foods of canids were the voles, plants and murid species. Whereas the plants took the first place (72.4%) in the analyzed samples of leopard cat, and birds (62.1%) and murid species (48.3%) took the following order places. The remains of plastic products had a higher occurrence rate at the areas with intensive tourism. The relationship of co-existence and competition among the predators was discussed through the comparison of food niche overlap. It suggested that the leopard cats took more birds and murid species as a food divergence to co-exist with other predators.
Long-PCR amplification, clone and primer-walking sequencing methods were employed in determine the complete sequence of mitochondrial genome of tokay (Gekko gecko). The genome is 16 435 bp in size, contains 13 protein-coding, 2 ribosomal and 22 transfer RNA genes. The mt genome of Gekko is similar to most of the vertebrates in gene components, order, orientation, tRNA structures, low percentage of guanine and high percentage of thymine, and skews of base GC and AT. Base A was preferred at third codon positions for protein genes is similar to amphibians and fishes rather than amnion vertebrates. The standard stop codes (TAA) present only in three protein genes, less than those of most vertebrates. Transfer RNA genes range in length from 63 to 76 nt, their planar structure present characteristic clover leaf, except for tRNA-Cys and tRNA-Ser (AGY) because of lacking the D arm.
Based on the experiments from 1998 to 2001 in the Haibei Research Station Alpine Meadow Ecosystem, the Chinese Academy of Sciences. Logistic Equations were used to describe the growth process of nestling of ten species Passerine birds for different varieties and several parameters of nestling process were derived from those equations. Basing on growth rule of nestling, we divided the growth process into three growth periods: slight growth period, fast growth period, and slow growth period. The ten species passerine were divided into two groups[ground or shrub, open or semi-open and semi-closing nesting birds (GOB) and hole nesting birds (HCB)]according to the type of nesting. The percentages growth period should vary in the order in GOB: fast growth period>slight growth period>slow growth period; this percentage in the order in HCB: slow growth period>fast growth period>slight growth period. We investigated the effects of nest type, nest predation and clutch size on each growth period. The percentages of each growth period in nestling period varies with nest types. Percentage of growth period and percentage of weight were affected significantly by nest type and predation. The length of fast and slow growth period were affected by clutch size, but the length of slight growth period was not affected by clutch size. The growth rate of slight growth period was not correlated with the accumulated weight of fast growth period but the number of slight growth period was strongly correlated with the accumulated weight of fast growth period. We think that anaphase growth is not affected by prophase energy accumulated, but the length of anaphase is affected by prophase energy accumulated. Our results are consistent with current theory that compensatory growth does not appear to occur in altricial birds.
Studies on effects of human activity on the foraging behavior of dunlins Calidris alpina were conducted using methods of focal-animal sampling and human-disturbance experiment at the beaches of Yanpen and Yuecheng, Yueqing bay in Zhejiang Province from November 2003 to March 2004. Results of focal-animal sampling showed that 96.6% of dunlins responded to human disturbances at a distance of 35 m or less by either running or flying. Dunlins spent 90% (94% in Yanpen with less people while only 85% in Yuecheng with more people) of the time foraging and 10% avoiding human disturbance generally. Number of persons and type of human activities had significant effects on foraging time, respectively. The distance and frequency of dunlin moved, and the response behaviors of dunlin to human approaching were significantly sensitive to the number of persons, the type of human activities and the distance from humans. The results of human-disturbance experiment indicated that the distances of dunlins responding to human were 3-30 m. The minimal approach distance to dunlins was significantly lager at one disturber than that at two disturbers, but no significant difference between two types of human activities, walking and running. This study tested the hypothesis that the human activities in shorebird foraging areas adversely affect the foraging behavior of dunlins.
Spring habitat selection by four eyespotted turtle (Sacalia quadriocellata) was studied from March to April 2004 in Limu Mountain of Hainan Island which geographically locates in 19°07′-19°14′N, 109°39′-109°49′E. Using regular sampling, elevation ranging from 170 to 1 170 m, a total of 196 representative plots were sampled in the mountain stream and the distance between every two adjacent plots was 60-90 m. At every selected plot, a bamboo cage with rotten beef as bait was placed for six days to catch turtles. Fourteen ecological factors (including width of water, depth of water, speed of flow water, substrate types, percentage of exposed stones, food abundance, vegetation types, coverage, thickness of deciduous leaves, elevation, slope degree, soil types, number of stone caves, distance to human disturbance) were measured at every plot. A total of 36 S. quadriocellata were caught at 26 plots below 500 m and no S. quadriocellata was caught above 500 m. Kruskal-Wallis Test was used to analyze the difference between the usage plots (n=26) below 500 m and contrastive plots (n=26) above 500 m. Of the 14 ecological factors, only the difference in number of stone caves between usage plots and contrastive plots is insignificant. This indicates that the environment above 500 m is rather different from that below 500 m. Principal components analysis were used to analyze the important factors which affect spring habitat selection by S. quadriocellata. The result showed that six important factors were as follows in decreasing order of importance: elevation, distance to human disturbance, coverage, soil types, water depth and thickness of deciduous leaves. And the influence of vegetation types, food abundance, percentage of exposed stones, substrate types, slope degree, number of stone caves, width of water and speed of flow water on spring habitat selection by S. quadriocellata was insignificant. To protect the vegetation near riverside and to improve local peoples conservation awareness are very important for the conservation of S. quadriocellata.
By radioimmunoassays, we analyzed fecal estradiol (E2) and progesterone (P) concentrations of four female red pandas (Ailurus fulgens) from Chengdu Zoo and Chengdu Research Base of Giant Panda Breeding from December 1999 to April 2000. Meantime, we investigated mating activity of the red pandas. The results showed that there was a rapid increase in E2 concentration, accompanying several peaks. This implied that female red pandas might be seasonally polyestrous. Before mating, E2 concentration reached the peak, meanwhile, P concentration also increased. This indicated E2 and P were both important factors for promoting the females mating activity. The copulation couldnt occur when E2 concentration reached the peak without P concentration increase, which was a dark rut. P concentration increasing continually after mating, presumably, an ovulation phenomenon had occurred according to the females kittening later. This implies that the ovulation mode of red pandas primarily is inductive, and the inductive factor is mating stimulation.
The genetic diversity of Hydra robusta was studied by RAPD technique from 17 populations of 10 distribution areas in Heilongjiang Province. Nineteen primers were selected from 80 random primers, and yielded a total of 320 bands ranging from 0.3-3.0 kb, 299 (93.44%) of which were polymorphic. The result indicated high level of genetic diversity in this species. The values of genetic identity (GI) and genetic distance (GD) of those populations were 0.7158 and 0.3425 on average, respectively. GD within distribution areas (0.1695) was lower than that between (0.3425). Cluster analysis showed that GDs of populations were consistent with their geographic distances. The population of Hutou had a clearly lower genetic identity with others (GI=0.5413 and GD=0.6161 on average) and was considered a relatively specialized one.
The structures of bird communities and guilds were compared among three successional-stage forests (deciduous forest,mixed forest and coniferous forest) to evaluate the effect of natural succession on breeding bird communities. The number of bird species, species diversity and guild diversity were the highest in the mixed forest and the lowest in the deciduous forest. Results from multiple comparisons and cluster analysis showed that there were differences in bird communities among three stages. Eleven of 36 recorded bird species differed significantly among three successioanal stages. Guilds also showed different responses to natural succession. For example, frugivore and gramnivore were most abundant in the mixed and deciduous forests. From a conservation point of view, bird biodiversity will be favored by the protection of all successional stages since different stages possess different bird communities and guilds. Artificial disturbance is recommended to maintain three successional stages, and, consequently, to maintain bird species diversity at the landscape scale.
In order to identify the relationship between geographic subdivision and population genetic structure due to habitat loss and fragmentation, the complete sequenes of the mitochondrial control region from 28 Chinese giant salamanders collected from Yangtze River Region (Hunan and Shaanxi), Yellow River Region (Henan) and Pearl River Region (Guangxi) were sequenced. According to the analysis of Clustal X, MEGA2.0, DnaSP4.0 and Arlequin1.1, 64 nucleotide sites were variable, including 6 transitions, 2 transversions and 11 insertions/deletions in the complete D-loop gene sequence (771 bp). A total of 27 haplotypes were identified and the average genetic distance among all these haplotypes was 1.32%. Furthermore, the results showed that all three geographic regions exhibited low levels of nucleotide diversity and haplotype diversity, in which the two indexes of Yangtze River were the lowest. The results also presented that there was significantly distinctive geographic phylogeography between Pearl River Region and Yangtze River Region, between Pearl River Region and Yellow River Region (all P<0.001), but no obvious subdivision between Yangtze River Region and Yellow River Region (P>0.05). In addition, and the genetic variation within and between regions was 99.31% and 0.69% respectively, which means the genetic variation mainly happens within the geographic region and gene flow among the geographic regions was comparatively frequent. At last the phylogenetic tree analysis (NJ method and MP method) demonstrated that all the haplotypes could not be clustered to three geographic clades, but appear disordered distribution pattern.
①Twenty 240 d old Yuehuang hens were equally divided into 2 groups and respectively inoculated I.m. with recombinant leptin or BSA immunogen (containing 1 mg protein in 1 mL mineral oil emulsion adjuvant, n=10 in each group) on days 3, 31, 63 and 84, blood sampled on days 1, 31, 53, 78 and 91 in the experiment. The plasma anti-leptin antibody titres following 1st inoculation became significantly (P<0.01) higher than in the control hens, so were plasma leptin levels,which steady increased following repeated immunizations. Plasma total T3 and total T4 levels were slightly lower but not significantly different (P>0.05) in treated hens following repeated inoculations from levels in control hens. The laying rates was significaltly depressed (P<0.05) by leptin immunization by 50% after the 3rd inoculation. Feed intake was slightly lower whereas live weight slightly higher in leptinimmunized than in the control hens. The abdominal fat mass was significantly higher in treated than in control hens (115.60±15.07 g vs 77.98±5.70 g,P<0.05) on day 98. ②Twelve 50 d old pullets were I.m. injected with anti-Leptin antibody in yolk extracts (n=6) or physiological saline (n=6). Pullets passively immunized against Leptin exhibited significantly higher (P<0.05) accumulative feed intake at 2, 4 and 6 h post injection than the saline injected controls. However the total feed intake of the 2 groups were identical at 8 h postinjection (P>0.05). The above results mimicked the biological effects of loss of leptin bioactivities observed in mammals and implied correctness of so far cloned chicken leptin gene, therefore contributed to clarify the disputes regarding this gene.
By semi-quantitative RT-PCR method and Southern blotting technology, growth hormone (GH) gene expression was determined in extra-pituitary tissues of green sunfish, Lepomis cyanellus. After the condition of semi-quantitative RT-PCR was established, 12 tissues of 6 months old (larvae stage) and 1 year old (mature stage) male L. cyanellus were detected. The results showed that GH gene was expressed in muscle, gonad, gill, heart, brain, and kidney in different level besides pituitary gland, and that no GH expression was detected in spleen, liver and stomach. Unexpectedly and interestingly, GH expression in muscle of adult fish was distinctly higher than that of sexually immature fish. In addition, the transcript levels of GH mRNA in the gonad of larvae and adult fishes were high. The data presented here provide the first systematic report of universal GH gene expression in extra-pituitary tissues in fish, suggesting that GH through autocrine or paracrine pathway exerted its possible important local physiological function during development and growth of L. cyanellus.
Using in situ hybridization with DIG antisense RNA probe, we detected the expression and distributing of goldfish (Carassius auratus) DEAD-box family gene vasa during oogenesis and spermatogenesis. The results showed that during oogenesis, the positive signals of vasa RNA were detected in the cytoplasm of oocytes at all stages. In stage Ⅰand Ⅱ oocytes, strong hybridization signals of vasa RNA were dispersed uniformly throughout the cytoplasm. With the development of oocytes and accumulation of yolk, the signals of vasa RNA significantly decreased in most of the regions while remained strong at cortical region in stage Ⅲ, Ⅳ oocytes. During spermatogenesis, the positive signals of vasa RNA could only be detected in spermatogenia and primary spermatocytes while the signals in the former were much stronger than in the latter. However, no signals could be detected in spermatids. Our results suggested that gene vasa may play an important role in the early stage of goldfish spermatogenesis; vasa RNA is deposited in oocytes and subsequently regulate the germ cells specification and differentiation during the early embryogenesis.
Neurogenesis and development of the central nervous system in the embryo stage of swimming crabs, Portunus trituberculatus, were studied by the histological method. The brain appeared at the egg-nauplius stage Ⅱ and was composed of protocerebrum, deutocerebrum and tritocerebrum under microscope. The protocerebrum was composed of lamina ganglionaris, lateral protocerebrum and medial protocerebrum at the egg-zoea stage Ⅱ, and olfactory lobe appeared and arranged beside the esophagus with deutocerebrum and tritocerebrum. The ventral nerve cord of the crab in the embryo included 1 pair mandibular neuromere, 2 pairs neuromeres of maxillae, 2 pairs neuromeres of maxillipede and abdomen nerve cord. Under microscope, the mandibular neuromere appeared at the egg-nauplius stage Ⅱ, the neuromeres of maxillae and neuromeres of maxillipede appeared at the egg-zoea stage Ⅱ, and the abdomen nerve cord formed at the egg-zoea stage Ⅲ. The central nervous system was composed of brain and ventral nerve cord in the embryo stage of the swimming crab. The brain was composed of protocerebrum, deutocerebrum and tritocerebrum. The brain connected to the suboesophageal ganglia with circumoesophageal fibre. The forming time of the part of the central nervous system showed difference in the embryonic development.
Using a stripsampling method, the birds resource was investigated at three areas (Tianpingshan, Sanmujie and Doupengshan) of Mt. Badagongshan, Hunan in summer from 2002 to 2004. Further more, Shannon-Wiener index (H′) and Pielou evenness index (J) of birds was calculated. Seventy-seven species belonging to 10 orders and 27 families are recorded. Among of them, there are 22 summer migrant and 55 resident species; 6 class Ⅱ protected wildlife of China and 7 provincial protected species; 43 oriental, 18 paratactic and 16 widespread species, and its geographical variation is Oriental realm, Huazhong section, and Western hilly area-highland sub-section. Analyses show that the bird diversities of Tianpingshan, Sanmujie and Doupengshan mainly relate to the area elevation and human disturbance, that is elevation lower, and habitats diversity higher, then H′ also higher; human disturbance higher, then J lower. The H′ and J values of Mt. Badagongshan are 1.5838 and 0.8395, respectively, are lower than those of Hupingshan, where the elevation is the lowest, and higher than Wulingyuan, where has been developed a tourist enterprise, in North-west of Hunan.
The cryoprotective effect and toxicity of Bovine Serum Albumin (BSA) at 8 concentrations (0, 2, 4, 8, 16, 32, 64, 96 mg/mL, respectively) supplemented in cryoprotectant solutions on mouse pronuclear-stage embryo vitrification were studied. Survival rate, cleavage rate, blastocyst rate and mean cell numbers of blastocyst of vitrified embryos were used as criterion to evaluate the effect of BSA on the post-thawed embryos development. The results showed that no statistical differences of survival rate, cleavage rate, blastocyst rate and mean cell numbers of blastocyst of vitrified groups both in the toxic effect assay (P>0.05) and the vitrification assay (P>0.05). The results indicated that BSA in this cryoprotectant solutions has no effect on the viability of pronuclearstage embryos. Economical, practical and biosecure considerations do not support the use of BSA in vitrificationsolutions.
In order to understand the molecular mechanism of olfaction of housefly, Musca domestica, we constructed a cDNA library using the Creator[TM] SMART[TM] cDNA library construction kit (Clontech). Total RNA was isolated from the housefly antenna using TRIzol Reagent. The PowerScript[TM] reverse transcriptase was used to synthesize and anchor the first-strand cDNA. Following reverse transcription, LD-PCR was performed using a modified oligo (dT) and an anchor primer to enrich the cDNA population for full-length sequences. cDNA size fraction, ligation and transformation into E. coli were continued to generate the oriental, unamplified cDNA library. The unamplified cDNA library has a titer of about 6.3×10[8] cfu/mL, in which the recombinant clones with an average insert size of 1.7 kb were about 91%. Amplification of oriental library is vital to obtain enough high quality plasmid for library screening and for long-term storage of the library. A full-length odorant binding protein (OBP) cDNA with 5′ and 3′ untranslated regions was isolated from the cDNA library, and named MdomOBP3 (GenBank Accession: AY826189). Sequencing and analysis show that the OBP cDNA is characterized by typical conservative Cys. Deduced amino acid sequence is highly similar to that of six OBPs from Diptera, with sequence identity of 59%-82%.
Female mice after 8 weeks were superovulated with PMSG and hCG, and their eggs were taken as recipients. Meanwhile cumulus cells around oocytes were also collected and used as donor cells in somatic cell nuclear transfer. Oocytes injected with donor cell nuclei were activated for 6 h by treatment in M16 media modified containing SrCl[2], and then cocultured with mouse oviduct epithelial cell in mM16 medium. When being in the stage of blastocyst, they were transferred on the feeder layers of mouse embryonic fibroblasts, adding ES cell media conditioned. After hatched from blastocysts, ICM were isolated and trypsinized, and then cocultured continuously to gain ES cell masses. Results indicated that activation rate of embryos reconstructed was 65.23%, development rate of blastocyst was 11.69%; ES cell colonies were isolated from 9 blastocysts reconstructed, isolation rate was 2.77%. ES cell colonies isolated were with islandlike images and strong positive by AKP staining, could become embryo bodies and spontaneously differentiate into epidermal-like cells around them in vitro. In addition, after frozen and thawed routinely, ES cell colonies were with strong proliferation and previous image. It indicates that mouse oviduct epithelial cell, modified M16 media and ES cell media with cardiomyocyte media can be more successfully applied in mouse somatic cell nuclear transfer and isolation of ES cell from reconstructed embryos.
Protozoan flagellates of the genus Trypanosoma are first found in fish, subsequently found in almost all classes of vertebrates and transmitted from host to host by blood-sucking arthropod or leech vectors. They are harmful to host. Based on the data of phylogeny in trypanosome, the origin, phylogeny and evolution of trypanosome, coevolution between host and trypanosome parasite, and present existing problems were reviewed in this article.
Membrane fluidity means the fluidity of membrane lipid in the unit membrane. The changes of neuronal membrane potential, ion flux, release and binding of neurotransmitters, enzyme activity and signal transfer will induce the changes of neuronal membrane fluidity. The membrane fluidity of brain neurons of aged animals and Alzheimer s patients is lower than that of young animals and normal people. The decrease of membrane fluidity is related to the increase of lipid peroxidation induced by increased free radicals. In addition, the disorder of intracellular calcium homeostasis, decrease of density of membrane receptor, and deposit of amyloid-β protein (Aβ) in the neurons of the brain also affect the membrane fluidity. The nootropic drugs, such as Pyrrolidone derivatives, Ginsenoside Rg1 and EGb761 significantly improved membrane fluidity of neurons in the aged animal and Alzheimer s disease patient s brain via above mechanisms.