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2008年  第29卷  第3期

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研究论文
Recent molecular cytogenetic studies demonstrate that extensive centromere-telomere fusions are the main chromosomal rearrangements underlying the karyotypic evolution of extant muntjacs. Although the molecular mechanism of tandem fusions remains unknown, satellite DNA is believed to have facilitated chromosome fusions by non-allelic homologous recombination. Previous studies detected non-random hybridization signals of cloned satellite DNA at the postulated fusion sites on the chromosomes in Indian and Chinese muntjacs. But the genomic distribution and organization of satellite DNAs in other muntjacs have not been investigated. In this study, we have isolated four satellite DNA clones (BMC5, BM700, BM1.1k and FM700) from the black muntjac (Muntiacus crinifrons) and Fea’s muntjac (M. feae), and hybridized these four clones onto chromosomes of four muntjac species (M. reevesi, M. crinifrons, M. gongshanenisis and M. feae). Besides the predominant centromeric signals, non-random interstitial hybridization signals from satellite I and II DNA clones (BMC5, BM700 and FM700) were also observed on the arms of chromosomes of these four muntjacs. Our results provide additional support for the notion that the karyotypes of M. crinifrons, M. feae and M. gongshanensis have evolved from a 2n = 70 ancestral karyotype by a series of chromosome fusions.
The complete sequence of Teleogryllus emma mitochondrial genome was determined using long PCR and conserved primer walking approaches. The results showed that the entire mitochondrial genome of T. emma was 15 660 bp in length, with an A+T content of 74.3%. The most distinct feature of this mtDNA is that the tRNA genes of Glutamic acid, Serine and Asparagine are located in the minor strand, and thus constitutes the third type of gene order of mitochondria in Orthoptera. The intergenic spacers range from 1 to 24 bp in size, totaling 73 bp. A total of 54 overlapping nucleotides exist among 14 genes, ranging from 1 to 11 bp in size. The TAA and TAG codons are used as stop codons in all the protein coding genes (PCGs) except COII, ND5 and ND4. The COI gene has an unusual start codon, TTA, instead of ATN or NTG. Most of the tRNA genes, except tRNASer (AGN), form typical secondary structures. An A+T rich region of T. emma mitochondrial genome with 940 bp in length exists as an ubiquitous secondary structure found in the Orthoptera and other orders of Insecta, such as Diptera, Lepidoptera, Hymenoptera, but not in Collembola, which is considered the basal group of Insecta.
Esox reieherti Dybowsk genomic microsatellites were developed by using enrichment protocols combined with radioactive hybridization protocol. Four hundred to nine hundred base pair fragments were selected for the whole genome. DNA PCR amplification after digestion with restriction endonuclease Sau 3AⅠ, and (CA)12, (GA)12 probes marked with biotin were used for microsatellite DNA enrichment. The product fragments were connected with carrier pGEM-T and transferred into DH5α Escherichia coli competent cells, and radioactive isotope probes marked with γ-32 P were used for the second hybridization. As a result, a total of 1600 bacteria were obtained in the microsatellite genomic libraries, positive clones accounted for 90.91% before hybridization and 81.25% after hybridization, amounting to 1300. One hundred and ninety-six positive clones were selected for sequencing, and 192 clones included microsatellite sequences. The microsatellite sequences obtained, mono-nucleotide, quad-nucleotide and quint-nucleotide repeat motifs were observed beside double-base-pairs CA/GT, GA/CT. Seventy primers were designed according to the flanking sequences by using software Primer Premier 5.0, and 32 primers were selected to be synthesized. After optimizing PCR reaction conditions, 28 primers were amplified and produced clear purpose bands. The aim of our research was to promote the development and utilization of E. reieherti genomic resource, and lay the foundation for optimizing E. reieherti breeding strain in order to detect the genetic diversity and construct a genetic map.
The Chinese alligator (Alligator sinensis) is a critically endangered species in China. Wild populations of Chinese alligator are on the edge of extinction. Through a release program, some captive-bred alligators will be selected and released into the wild to supplement and renew natural populations. The purpose of this study was to provide data to select healthy individuals for release. Through bacteriological and molecular identification, six different genera, eight species and an unclassified bacterium were identified in 13 bacterial strains, which were isolated from the cloaca of 25 Chinese alligators. One genus and four species were identified in eight bacterial strains, which were isolated from the water where the alligators live. According to the analysis, except for the unclassified bacterium, the other bacteria from the cloaca were not pathogenic and were different from the bacteria isolated from the water. Thus, it was concluded that the 24 Chinese alligators were healthy, and could be selected to be released into the wild. As subject AS12 was identified carrying an unclassified bacteria, of which the characteristics were unknown, it was suggested that the AS12 individual not be released.
The orbitofrontal cortex (OFC) is particularly important for the neural representation of reward value. Previous studies indicated that electroencephalogram (EEG) activity in the OFC was involved in drug administration and withdrawal. The present study investigated EEG activity in the OFC in rats during the development of food reward and craving. Two environments were used separately for control and food-related EEG recordings. In the food-related environment rats were first trained to eat chocolate peanuts; then they either had no access to this food, but could see and smell it (craving trials), or had free access to this food (reward trials). The EEG in the left OFC was recorded during these trials. We showed that, in the food-related environment the EEG activity peaking in the delta band (2-4 Hz) was significantly correlated with the stimulus, increasing during food reward and decreasing during food craving when compared with that in the control environment. Our data suggests that EEG activity in the OFC can be altered by food reward; moreover, delta rhythm in this region could be used as an index monitoring changed signal underlying this reward.
The study was conducted to investigate the effects of vitamin E (VE) on reproduction endocrine and ovary structures in mice acutely treated with TCDD. Twenty-four mice were divided into control groups, TCDD-treated with 30 µg/kg group, and a TCDD-treated with 30 μg/kg followed with 100 mg/kg vitamin E group. The level of progesterone and estradiol of plasma were analyzed by radio-immunity methods. The number of ova and the ovary forms were counted and observed under the microscope. The results showed that TCDD obviously decreased the level of plasma progesterone and the number of ova, changed the forms of ovaries, while 100 mg/kg VE significantly alleviated these effects caused by TCDD. TCDD and VE had no significant effects on the levels of plasma estradiol. The results indicated that VE had anti-actions on the endocritic function and a decrease in the progesterone level and the ova number in mice, caused by TCDD.
Nesting has important effects upon birds’ growth and breeding. We studied nesting characteristics of Yellow-bellied Prinia by marking and measuring nests of study sites at Jiangxi village, Guangdong from March to September in 2007. For each active nest-site, we made a 5 m×5 m sampling plot with the center of each nest to sample habitat index, and then analyze nest-site selection using Principal-component analysis. The results showed that: 1) Yellow-bellied Prinia started nesting in the middle of March, reached its peak in April, and was completed by late July. 2) A total of 44 nests were found in 13 species of plants; 27 nests were built in Pennisetum purpureum, 4 in Erigeron canadensis and 1 or 2 in other species. 3) All nests were irregularly sphere-shaped, included artifactitious materials besides vegetation and creatural Materials. 4) Four factors were found to affect birds selecting their nest-sites: distance from the nearest water sources (29.89%), distance from the nearest road (16.45%), distance from the nearest bush (12.92%), and height above water surface (11.69%). Hence, we concluded that the pattern of nest building of Yellow-bellied Prinia was a way to adapt to their environment, and shorter tails could not only increase flexibility, but also reduce nesting investment.
The songs of Yellow-bellied Tits (Parus venustulus) were recorded during April and March, 2006 and June, 2007 in Beijing Xiaolongmen forest. The acoustic characteristics of songs were measured and analyzed with Avisoft-SASLab Pro software (Germany). The songs of Yellow-bellied Tits have simple verse structure, formed with repeat syllables. The repertoire of Yellow-bellied Tits includes 56 syllable types. Significant positive correlation was found between the number of syllable types and sampling individuals (r=0.973, P=0.000<0.05). Differences in territory songs found among individuals may be related to individual identification. Compared with four other species distributed in the same area, the Yellow-bellied Tit had the shortest verse (Dv =0.83±0.48), higher maximum frequency (Fmax=7.64±1.01, Fmin =3.27±1.13), and the least repeat syllables in its verse (Ns.v=2.0±0.2).
Bird song is an important way of studying bird behavior in the field. To understand the relationship between songs and tail action of Plain Prinia(Prinia inornata),we studied their territorial songs during August and October in 2007 in Jiangxi Village of Zhaoqing,Guangdong. The results showed: 1) Plain Prinia had six song types,four were frequent, one transitional and one scarce type. 2) The song was simple but its type varied,indicating different types and degrees of danger. 3) The four song types had connections with different behaviors,and each song was accompanied by tail shaking. Therefore,we concluded that the structure of the songs was simple but varied a lot,and tail action had a function in these territorial songs.
From November 2006 to February 2007, the characteristics of the feeding sites of Purple Swamphen (Porphyrio porphyrio) in winter were studied in Guangdong Haifeng Avian Natural Reserve, by sampling methods. The results showed that there was obvious selectivity of the vegetation in the feeding sites during winter, and Scirpus tabernaemontani was the preferred flora. We found that the main selection factors at the feeding sites in winter using the principal component analysis of 18 factors at 62 feeding sites, were the density of herbage, the height of herbage, the canopy of herbage, the shrub species, the water quality and the water level. In addition, we found that the main selection factors at the feeding sites using the Step DA between feeding sites and control samples plots, were the height of hay, the abundance of animal foods, the distance to the road, the herbage species, the distance to the byway and the distance to the water’s edge. The veracity to distinguish was 78.1%. Purple Swamphen preferred to feed in areas that had more Scirpus tabernaemontani or Phragmites communis, special water levels or water quality and medium interference from humans. Thus, restoration and protection of the extant feeding sites in winter are important for the conservation of Purple Swamphen.
This study investigated species composition and diversity of fish larvae and juveniles in the surf zone of the Yangtze River estuary to reveal the importance of this habitat as a fish nursery ground. Fish larvae and juveniles were collected monthly at 13 stations on the spring tide during July 2006 and June 2007. Samples were conducted along the surf zone (depth of 0.5-1.5 m) using a seine net (1 m×4 m, 1 mm mesh-aperture). Each haul was made parallel to the shore for a distance of about 50 m. A total of 49 045 fish larvae and juveniles were collected representing 84 species from 31 families. They included 16 marine species, 30 estuarine species, 4 diadromous species and 34 freshwater species. Coilia nasus was the most dominant species accounting for 82.63% of the total. The number of species, individual and abundance were lower in winter with the minimum number in March and maximum in summer. The Margalef index was relatively low between November 2006 and April 2007, the highest being in October 2006. The Shannon-Wiener diversity index was the highest in October 2006 and the lowest in March 2007. The Pielou evenness index was invariable throughout the whole year and relatively low in July 2006 and June 2007.
Laboratory experiments with split—plot block design were conducted to examine the effects of soil temperature and moisture on cocoon production and hatching of the exotic earthworm Pontoscolex corethrurus under controlled conditions. Results showed that consecutive cocoon production and hatching took place at all three soil temperatures and at the two higher soil moisture conditions, used in this experiment. Cultivation time, soil moisture and temperature had significant effects on cocoon production and hatching of P. corethrurus. Earthworms suffered a diapause or even died when reared in soil with 20% moisture content. The greatest cocoon production and hatching rate were observed at 35% soil moisture content. When soil moisture was preferable (e.g. 35%), cocoon production was greater at higher temperatures than at lower temperatures. Hatching rate increased with soil temperature if the soil moisture content was preferable; however it was restrained if the temperature was too high or too low. The greatest hatching rate only occurred at a combination of 25°C soil temperature and 35% soil moisture content. The results also showed that soil moisture was the primary factor limiting the reproduction of P. corethrurus, the effects of soil temperature on earthworm reproduction was influenced by soil moisture.
A new species of Paramesotriton longliensis sp.nov. (Holotype: No.0705015, adult male; Allotype: No.0705019, adult female; Paratypes: 10♂♂, 10♀♀) was discovered during a survey of herpetofauna in Shuichang village, Longli County, Guizhou Province between May 4 to May 12, 2007. This new species can be distinguished by the following characteristics: the back part of the upper branchial bone points upwards, an obvious bulge presents on both sides of the branchia vestiges on the head, high edges stick out on the back, there is no fringe on the side of the fingers and toes, but there is a black cuticle at the end, the fold of the tail fin behind the anus is reddish orange, which fades away, while that of the adult male is purplish red, and has no stripes.
Monkeys do not express ABO antigens on red blood cells (RBCs), but on tissues, which is an obstacle in ABO typing. In this study we describe a simple and efficient method to type monkeys blood. Rhesus monkeys (n=34) and cynomolgus monkeys (n=16) were typed by the direct and reverse gel system, which has been widely used in clinics in recent years. Based on the results of immunohistochemical staining, we evaluated the feasibility and the interference factors of the gel system to type monkeys. The results revealed that the direct gel system didn’t have a positive report, the fibrinogen and non-specific anti-human antibodies in monkey blood interfered with the reverse gel system in some samples. In accordance with the results of immunohistochemical staining, using clear sera, which were pre-absorbed on normal human type O RBCs, the reverse gel system gave an accurate blood type determination for monkeys. We concluded that the reverse gel system could be used for ABO typing of monkeys, and the fibrinogen and non-specific anti-human antibodies were the major interference factors, which could be eliminated by using clear and pre-absorbed sera.
The Red-breasted Flycatcher (Ficedula parva) and Taiga Flycatcher (F albicila) have long been considered having a conspecific status under the species Red-throated Flycatcher (F parva). Based on the studies on the morphology, vocalizations and molecular biology, the two subspecies have recently been split into separate species that are allopatrically distributed in the Palearctic region. Before our report, there was no formal record of taxon parva in China. Between April and May of 2007, two birds of parva were recorded respectively at Potoi Island, Hong Kong SAR and Xiangyundao Tree Farm, Laoting, Hebei Province, the first known recording of this species in China. We also briefly discussed the general characteristics and field identification of Red-breasted Flycatchers in this article.
Among the collection from Hekou County (the Bazi River,a tributary of the Nanxi River which flows into the Red River),six specimens of Pseudobagrus kyphus were identified as a new record of Bagridae species in Yunnan Province. It could be distinguished by a combination of the following characteristics: four pairs of barbels,short maxillary barbels,not reaching the pectoral-fin origin; adipose fin present,dissociated from the caudal peduncle; anal fin with 16–18 rays; anterior edge of pectoral and dorsal spines without serrations; a dark blotch appearing on the margin of the dorsal fin and stripes appearing on the upper and lower lobes of the caudal fin.
A specimen of White-spectacled Warbler Seicercus affinis was collected in Diding Nature Reserve in Jingxi County, Southwest Guangxi province in December 2006. It is a new record of bird species in Guangxi. During our field investigation in Diding Nature Reserve from January 2005 to May 2007, Seicercus affinis were observed frequently in the underbrush of the evergreen broad-leaved forest and the shrub around agricultural land at an altitude of 500-700 m. There are two subspecies of Seicercus affinis recorded in the world, but only one in China. Through a careful examination, this specimen was identified as Seicercus affinis intermedius. The distribution of Seicercus affinis in China will be discussed in this paper. The specimen was kept at the College of Animal Sciences and Technology, Guangxi University.
The retroviral vector (RCAS) has been widely used in avian system to study development and diseases, but is not suitable for mammals which do not produce the retrovirus receptor TVA. In this review, we trace the current uses of RCAS-TVA approach in mammalian system with improved strategies, including generation of tv-a transgenic mice, use of soluble TVA receptor and retroviral receptor-ligand fusion proteins, improvement of RCAS vectors, and compare a series of mammalian models in variant studies of gene function, development, oncogenesis and gene therapy. All those studies demonstrate that the RCAS-TVA based mammalian models are powerful tools for understanding the mechanisms and target treating of human diseases.
Satellite tracking, based on the Argos satellite system, has been used in the studies of migratory birds since the 1980’s, and ornithologists have learned a lot using this method. But it is not widely used by Chinese ornithologists. We satellite-tracked several wintering Black-necked Cranes in Yunnan Province, in the winter of 2004, to confirm their migratory routes. We were also able to review the utility, advantage and development of this technology. Recent research has focused on discovering migratory routes and important stopover sites, finding new breeding and wintering areas, evaluating habitat quality and habitat use and discussing migration strategies. We hope this review might promote migratory studies and conservation of birds in China.