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2005年  第26卷  第5期

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研究论文
Between May and August 2002, microgeographic song variations of the Chinese Bulbul (Pycnonotus sinensis) were studied in Hangzhou, capital of Zhejiang Province in eastern China. We recorded 511 morning songs of 80 male Chinese Bulbul at eight locations: four locations in extensive mixed forest and 4 locations in urban woodlots, within an area of about 60 km2. We analysed the acoustic characteristics of typical sentences and their syllables of 160 songs, and randomly selected 20 songs for each location. The results showed that the Chinese Bulbul has obvious microgeographical song variations; specifically, that eight microgeographic song dialects were found in our survey area and each dialect had a typical song sentence. The microgeographical song variations of the Chinese Bulbul in Hangzhou occurred at different levels of acoustic characteristics, such as hearing, oscillogram, syllable composition, sonagram and spectrum. Obvious boundaries between microgeographical song dialects and also multibilingual individuals could be found in some survey locations. Additionally, the mixed areas in where individuals with different microgeographical song dialects occurred could be also found in our survey. The occurrence of microgeographical song dialects in the Chinese Bulbul might be related to individual dispersal of and changes of the habitats in urban areas.
The laboratory population was founded by the cross-fostering method. In order to investigate mechanisms of kin recognition by odor cues, we observed the behavioral responses of adult male root voles (Microtus oeconomus) to urine odors from females, which include non-siblings reared together (NSRT), non-siblings reared apart (NSRA), and siblings reared apart (SRA). The results showed that there are no significant differences in male vole body weight between siblings reared together and SRA during different developmental periods (age 2-70 days). Approach latency by males was significantly longer in response to NSRT than NSRA, whereas visiting time and sniff time by males were significantly shorter in response to NSRT than NSRA opposite-sex conspecifics. The behavioral responses of males to urine odors from SRA and NSRA had no relationship with the degree of genetic relatedness. In conclusion, male root voles 80 days in age can discriminate between familiar and unfamiliar non-kin by urine cues, but such males cannot discriminate between unfamiliar kin and non-kin. We conclude that male voles use an odor association mechanism for sibling recognition.
We analyzed the static life table, age structure and survivorship curve of blue sheep (Pseudois nayaur) using the horns of 102 male blue sheep that died of natural causes in tie field, from April to May, 2004, on Helan Mountain. The age of each horn was determined by the growth ring. We also compared the data from this study with data from 1995. The natural mortality rate between 1.5 and 4.5 years old ranged from 0% to 7.4% in this study. For rams between 5.5 and 10.5 years old the range was 14.9% to 25.0%. The mortality rate for rams with 11.5 to 15.5 years old varied between 40.7% and 100%. The first mortality peak (from 1.5 to 4.5 years old) in this study was similar to the results of 1995, while the second mortality peak (from 5.5 to 10.5 years old) was remarkably delayed. Unlike the results from 1995, 64.7% of individuals during this research survived up to 8 years old, and 7.8% rams survived until after 13 years. The 2004 data indicated that life expectancy of rams was close to that of 1995. However, life expectancy in the older rams (≥5.5 years) from this research increased significantly. We found a significant difference in the mortality rate of rams below 4.5 years old between 1995 and 2004. There was a significant difference in the mortality rate of rams from 5.5 to 9.5 years old between 1995 and this study. The mortality rate of rams over 4.5 years of age differed significantly between 1995 and 2004. Although the blue sheep populations on Helan Mountain have experienced some changes in the last ten years, the survivorship curve of rams was still close to convex type (A type).
This paper deals with the distribution and geographic division of grasshopper in Shaanxi province using GIS (geographic information system) techniques. 593 longitude and latitude grid cells (0.2°×0.2°) were used to count the species number of grasshopper and multi-analysis hierarchical cluster method was used in the cluster analysis. The results showed (1) the number of grasshopper species of southern Shaanxi are greater than that of the rest of Shaanxi, and the number of grasshopper species of Ordos Plateau are greater than that of Loess Plateau of northern Shaanxi. The 593 distributional units are clustered into 9 groups with proximity coefficients of 0.538 which resembles the physical division of Shaanxi. However, there are some differences in the distributional units as follows: Qinling mountain is divided into a southern and northern slope; Shangnan Hill is separated from Qinling Mountain; Ankang Area and Bashan Mountain from a single cluster of one group; Bashan Mountain and Micang Mountain are clustered into two paratactic groups. The cluster results also showed that there is a close relation between the geographic distribution of grasshopper in Shaanxi and its environment, and the distribution pattern of grasshopper has obvious zone differences. We conclude that the diversification of the geography and climate types of Shaanxi are the main reasons of the diversification of grasshopper species.
We studied caching behavior in the plateau pika Ochotona curzoniae in the Dawu, Guo Luo, Qinghai Province from July to October of 2004 when caching behaviour occurs. Counts of cradaled plant species were obtained using placement, quadrat sampling, and transection methods. The results showed that in the growing season plateau pika cached hay-piles for feeding in the winter. Plant species chosen by the plateau pika reflected their habitat vegetation. Plants collected by plateau pika were placed on plants with spacious leaves to prevent the hay-piles from rotting. The results of excavation indicated that plateau pika habitually store food in holes.
The nucleolus of the eukaryotic cell is the site of ribosome biogenesis and contains many protein factors required for ribosome biogenesis. As it has been previously shown that Giardia did not have a nucleolar structure, we want to know how ribosome biogenesis occurs in Giardia. Are there any differences between Giardia and the other eukaryotes with nucleolar structures? We first identified 129 conserved common proteins which are involved in ribosome biogenesis in typical eukaryotes. Then, we used these proteins as query sequences to identify the orthologs in Giardia genomic database. Our results indicate that there are 89 orthologs of the 129 ribosomal biogenesis proteins in Giardia, some of which are involved in rRNA methylation or pseudouridine and present in 90S, pre-40S and pre-60S particles. These data suggest the ribosome biogenesis system of Giardia is similar to that of typical eukaryotes. However, there are 40 ribosomal proteins that do not have obvious orthologs in Giardia. This may imply that the ribosome biogenesis system of Giardia is simpler than that of other eukaryotes. According to these results, we argue that although Giardia does not possess nucleolus, its mechanism and pathway of ribosome biogenesis are similar to that of typical eukaryotes but simpler, and are different from that of prokaryotes. The present investigation provides significant insights into the origin and evolution of the nucleolus.
In this study we designed several pairs of primers to clone and sequence the ebony gene of a new pigment mutant named black strip (bsr) in Drosophila melanogaster (Qian & Zhang, 1994). Compared with ebony gene of wild type w91910 and ebony mutant of e1, there was no big deletion segment found in coding sequence of ebony of bsr except for several amino acid mutation sites which did not distribute in the key motif of ebony protein. However, a big fragment deletion was found at the 5′ end of ebony gene in bsr, which comprised 206 nucleotides of exon 1 and 747 nucleotides of intron 1. Therefore we have been able to accurately localize the mutation locus in bsr.
Six culturing systems were designed by adding different concentrations of epidermal growth factor (EGF) and insulin into DME/Hams F12 medium. Based on the speed of cell growth and variation ratio of chromosome number, we chose the best culture media from the six culture systems. The results showed that the culture medium of 10 μg/mL insulin and 40 ng/mL EGF was most suitable for giant pandas cutaneous fibroblast culture in vitro. In the best culturing system, the density of fibroblast increased from (1.673±0.185)×10 5/mL to 6.890×10 5/mL for three and a half days. The fibroblast growing speed was the fastest in all culture system and the ratio of diploid at the 5th generation was 75.77%. Karyotype analysis showed that culture cell is from Giant Pandas body cell. In conclusion, CS-5 is more suitable for giant pandas cutaneous fibroblast culture than other culturing systems in vitro.
2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) is one of the most toxic environmental pollutants. The goal of this study is to understand the cause of the short lower jaw induced by TCDD in the zebrafish embryos. Embryos are exposed to TCDD (0-1.0 μg/L) at 24 h post fertilization (24 hpf) until the time of observation and studied by gene knockdown, immunohistochemistry staining and in situ hybridization. The results show that TCDD treatment leads to decreases in the size of the lower jaw and reduced Shh gene expression. This effect can be blocked by injection of Morpholino antisense oligos against AhR2, the potential TCDD receptor. We also find Cyclopamine, a Shh inhibitor, caused short lower jaw and decreased cell proliferation in the zebrafish embryos. These results suggest that TCDD might inhibit the expression of Shh through AhR and lead to decreased cell proliferation and short lower jaw in zebrafish embryos.
The expressed sequence tag of eukaryotic translation initiation factor 5 (eIF5) from the Schistosoma japonicum adult worm cDNA library through subtractive hybridization between male and female worms was analyzed by the bioinformatics method. The overlapping sequences were assembled into one that includes the complete open reading frame (GenBank accession number: AY686501). The full-length cDNA of SjeIF5 was cloned into a pET-28c(+) vector, which generated a prokaryotic expression plasmid, and a fusion protein of 18 kDa was induced in Escherichia coli. The recombinant expression of eIF5 protein of Schistosoma japonicum was purified. The immunoprotection test against schistosomiasis demonstrated that the recombinant protein worked to a certain extent, especially in the reduction of eggs in the liver of the host.
We studied the ultrastructure of the spermatozoon of northern grass lizards (Takydromus septentrionalis,n=5) collected in April 2003 from a population in Wenzhou, Zhejiang, eastern China. The mature spermatozoa are characterized by: A circular acrosome; an acrosomal vesicle divided into cortex and medulla; the unilateral ridge of the acrosome vesicle divided into cortex and medulla, the electronlucent zone between them; a prenuclear perforatorium, absence of the perforatorium base plate; presence of the subacrosomal space; an elongated nucleus, absence of a endonuclear canal; absence of epinuclear lucent zone; rounded nuclear shoulders. A bilateral stratified laminar structure within the neck region. A short midpiece; absence of multilaminar membranes; in longitudinal section, two tiers of mitochondria, in transverse section, six mitochondria with linear cristae; the presence of two dense body groups, the ring structure consisting of the complete ring; the arrangement pattern of the ring structure and mitochondria in rs1/mi1 and rs2/mi2; a fibrous sheath in the midpiece; presence of an annulus. A thin granular zone of cytoplasm at the anterior portion of the principal piece; the enlarged fiber 3 and fiber 8 disappearing at the anterior portion of the principal piece; the axoneme complex having an usual 9+2 pattern. Within lacertid lizards, sperms differ among species in the number of mitochondria, but in all species studied so far, there are two groups of dense bodies. However, lizards of different taxa differ, in various degrees, in such sperm morphological traits as acrosome vesicle, subacrosomal space, epinuclear lucent zone, perforatorium base plate, nuclear shoulder and number and arrangement of mitochondria and dense bodies. These differences suggest that sperm morphology provides additional information which one may use to study the phylogeny of lizards.
In order to investigate age-related morphological changes in the white matter of the lumbar spinal cord in young adult and old cats, several techniques were used. (1) Immunostaining of neurofilaments (NF) was used to identify nerve fibres; (2) modified Holzer crystal violet to show all the glial cells; (3) immunoreaction of glial fibrillary acid protein (GFAP) to exhibit the astrocytes; (4) the Golgi method to display the morphology of glial cells and astrocytes in the white matter. Under the microscope, the fibres and glial cells were observed and quantitatively studied. Compared with young cats, old cats showed significantly lower density of nerve fibres (P<0.01)and weaker staining of the NF immunoreactivity. However, the density of glial cells and astrocytes (P<0.01) in old cats is significantly greater than in young adult cats. In addition, astrocytes in old cats were more hypertrophic, with stronger immunoreactivity of GFAP substance than in young ones. This indicates that there is a loss of nerve fibres accompanied by an obvious glial hyperplasia in the white matter of the aging cat spinal cord. The above results suggest that the loss of nerve fibres in the white matter of old cats may be an important factor that underlies the functional decline of signal transmission and processing in the spinal cord during ageing. The activity enhancement of glial cells in old cats may provide a protective effect on surviving nerve fibers from further degradation during senescence.
We studied the spatial summation of excitatory post synaptic potentials (EPSPs) at proximal and distal dendrites of the hippocampal CA1 area by using two stimulating electrodes in anaesthetized Wistar rats. Our results showed that the summation of EPSP was sublinear both at the proximal and the distal dendrites of hippocampal CA1 area. As expected, EPSP amplitudes increased and the summation of distal dendritic EPSPs decreased (though tended to be more sublinear) but the proximal summation was not affected. Furthermore, bicuculline (GABA receptor antagonist) didnt affect the spatial summation of EPSPs, but AP-4 (antagonist of transient A type K+ channel) made spatial summation of the proximal dendrites linear. Our experiments demonstrate that hippocampal CA1 pyramidal neurons may use different patterns of spatial summation at proximal and distal dendrites. Proximal dendrites of hippocampal CA1 pyramidal neurons receive mainly the inputs from schaffer collateral/associational commissural pathways, whereas the distal dendrites receive mainly the inputs from entorhinal cortex through TA (temporoammonic) pathways. These results indicate that that two different summation mechanisms in hippocampal CA1 pyramidal neurons are used to process information (1) within the hippocampus and (2) from the entorhrinal cortex.
Shaoxing ducks raised in long-day (LD) or short-day photoperiods (SD) matured at different ages. The aim of this study was to investigate the central mechanisms behind this difference. The results were as follows: Ducks raised in LD grew faster and matured earlier than those raised in SD. LD and SD ducks attained puberty at 120 and 150 days of age, respectively. Additionally, the hypothalamic gonadotropinreleasing hormone-Ⅰ (GnRH-Ⅰ) pro-opiomelanocortin (POMC) and neuropeptide Y (NPY) mRNA abundance were detected by semi-quantitative RT-PCR using β-actin or 18S rRNA as an internal standard. The results showed that, even though the profile of GnRH-Ⅰ mRNA expression was similar between two groups, which increased progressively during sexual maturation, the level was higher in LD ducks than in SD ducks of corresponding ages, especially at 120 days of age (P<0.05). The levels of hypothalamic POMC and NPY gene expression showed different patterns compared with GnRH-Ⅰ gene. POMC and NPY mRNA reached the highest level on D60 or D90, then decreased significantly till D150. Multi-factor ANOVA analysis showed that the LD photoperiod stimulated the expression of hypothalamic GnRH-Ⅰ and POMC mRNA, but had no effect on NPY gene expression. These results suggest that the hypothalamic GnRH-Ⅰ gene is the key factor for the onset of puberty and earlier maturation for ducks raised in the LD photoperiod. Additionally, right before or at the onset of laying, the coincidence of down-regulation of POMC and NPY mRNA and up-regulation in GnRH-Ⅰ gene expression in hypothalamus indicates that GnRH-Ⅰ, POMC and NPY gene work synergistically underlying the onset of puberty in Shaoxing ducks.
The accumulations of three main energy sources: triacylglycerol, polysaccharide and soluble protein were determined in two psocids, Liposcelis bostrychophila Badonnel and L. entomophila (Enderlein). The results indicated that the reserves of three energy sources in L. entomophila were significantly higher than that in L. bostrychophila. Exposure of the two psocids to chlorpyrifos and carbosulfan was associated with a significant change of the reserves, and the change range for L. entomophila was greater than for L. bostrychophila. The triacylglycerol responded to the two insecticides with a parabolic increase in the reserves, while polysaccharide and soluble protein responded with an enhancement of the utilization rates. These changes suggested that under the effect of chlorpyrifos and carbosulfan, polysaccharide and soluble protein are the main energy sources, while the utilization of triacylglycerol decreased.
The chick embryo is a widely used experimental animal in developmental biology research. Heart rate (HR) is usually considered to be an important physiological index reflecting the embryos natural activity. The paper introduces in detail a new invasive method for heart rate recording. With wire electrodes implanted by drilling small holes in the eggs shell, signals are amplified and digitised using an A/D converter. The heart rate (HR) could be measured under normal physiological conditions, and thus the normal embryonic development is not significantly affected by the recording procedure. In addition, the signals are large in amplitude and easy to manipulate.
Tandem repeat sequences, also known as direct repeats, are repeat sequences in which the length of the repeat unit changes mainly from 1 to 200 bp size, and the repeat unit is arranged in a “head-tail” conjunction mode, and is distributed widely in the genome of eukaryotes and some prokaryotes. At the level of full genomes, both the abundance and distribution characteristics of repeat types, such as dinucleotide repeats and trinucleotide repeats et cetera are varied in different organisms, and the variedness also occurs in different repeat classes, such as AT and AC repeat classes etc. and across inter-chromosomes, and even between coding regions and noncoding regions. All of the above differences indicate that the genesis and evolution of tandem repeat sequences are complex and may involve several mechanisms and factors, as is typical of biology. Additionally, there exist some problems preventing us from further studying the tandem repeat sequences, e.g. the software to analyze repeat sequences, criteria such as the length, the copy number, and the perfect or imperfect delimitation to determine what is a repeat sequence or not which varies across researchers. In order to address these problems, six future research directions should be pursued: The study of tandem repeat sequences, the self-evolution relations of tandem repeat sequences, the evolution status in the level of full genomes, the biology function, the establishment of tandem repeat sequence data-banks, and their application researches.