2009 Vol. 30, No. 1
In order to analysis the genetic structure and demographic history of Boleophthalmus pectinirostris, the random amplified polymorphic DNA (RAPD) technology and mitochondrial cytochrome b (Cyt b) gene sequences were used in the study. The results showed that there was high level genetic diversity in the populations of B. pecinirostris in Yangtze River estuary and its southern wet-land adjacent regions. (1) RAPD was conducted to analysis the genetic variation of B. pecinirostris in Jiuduansha (JDS), Dinghai（DH）and Xiapu（XP）for 20 individuals per population, with 30 polymorphic 10-based random primers selected from 100 ones. In total, 236, 270 and 274 bands were obtained for JDS, DH and XP, respectively and there was 301useful loci. The range of proportion of polymorphic loci (P), Nei’s gene diversity (H) and Shannon diversity index (I ) was: 93.02%–96.3%, 0.3890–0.4219, 0.5618–0.6044, respectively. The results of AMOVA showed significantly genetic differentiation (Fst=0.03004-0.03254, P<0.05) but there was only 3.2% genetic variation among populations. (2) Results of Cyt b gene: the total Cyt b gene length was 1 141 bp and 33 haplotypes were obtained from 42 individuals collecting in 4 different regions, which included JDS, DH, XP and Cixi (CX). The average haplotype diversity (h) and nucleotide diversity (π) was 0.9184, 0.0048, respectively. The high level of Nm values (14.50–30.79) and low Fst values (0.0043–0.07814), the average K2-P distances (0.0040–0.0056), as well as the AMOVA analysis (total Fst=0.0193, P>0.05) all revealed that the B. pecinirostris had no obviously geographical differentiation. However, the phylogenetic tree estimated by neighbor-joining (NJ) method indicated that the individuals of B. pecinirostris formed two monophyletic lineages, and the two lineages were not correlated with geographical populations. Neutrality tests, mismatch distribution and network analysis suggested a late Pleistocene population expansion for B. pecinirostris (0.057–0.023 million years ago).
2009, 30(1): 11-16. doi: 10.3724/SP.J.1141.2009.01011
In order to explain the process of biological evolution based on some conditions, the differential equation deduced from directional selection describes the evolutionary process of two populations (species) which share the same resource without amalgamation. Although it is generally held that the larger population obtains better chances of survival, such view is not complete. By using differential equations and computer simulations, we found that, when a population gains beneficial mutation, the other population will go extinct regardless of its initial conditions. The larger population is superior since it is more likely to obtain advantageous mutation if the rate of advantageous mutation remains constant between the two populations. On the other hand, if both populations have favorable mutation, the chance of the survival for the smaller population will be apparently better.
Partial sequences of the mitochondrial DNA cytochrome c oxidase subunit I gene (COI) of seven Tegillarca granosa populations, which were collected from China's coastal areas, were amplified by polymerase chain reaction (PCR). The length of COI gene of 38 Tegillarca granosa individuals from seven populations was all 660bp. One hundred and three variable sites were detected in the nucleotide sequences of 660 bp, and 17 different haplotypes were identified. The result showed that the seven populations could be divided into two groups based on the the genetic distance and phylogenetic analysis of their COI gene sequences. The two groups were classified as Group in the Northern Fujian (including Fujian) and Group in the Southern Fujian. Group in the Northern Fujian was composed of five populations and the genetic distance was 0.0016. Group in the Southern Fujian was composed of two populations and the genetic distance was 0.0006. However, the genetic distance between the two groups was significantly high (0.1529), which suggested significant genetic differentiation between the two groups. It suggested that Group in the North of Fujian (including Fujian) and Group in the South of Fujian should be the same species, but they were different subspecies.
Tree shrews（Tupaia Belangeri）are phenogenetically close to humans and primates and generally recognized as a prominent small animal model for studies of heptitis virus type B (HBV). Isolating and culturing tree shrew hepatocytes is the first key step toward the cellular model of HBV infection in vitro. Due to the lack of details in previous reports, establishing the model has been a matter of arbitary experiences. In this study, we validated the superiority of perfusion over mechanic dispersion for hepatocyte separation and isolation. Subsequent cultures showed that dimethyl sulphoxide (DMSO) could suppress the growth of fibroblast-like cells and maintain the hepatocytes in the differentiated status. Furthermore, hepatocyte growth factor (HGF) and epidermal growth factor (EGF) could sustain growth and survival of the hepatocytes in the long-term culture. The combination of DMSO and HGF/EGF could maintain the hepatocytes in a longer and more stable differentiated status with clear trend to form liver sinus-like structures. Following this detailed method as a laboratory routine would permit plentiful starting material for study of HBV infection in vitro and drug-screening, as well as studies on hepatitis viruses type C and D, and herpes simplex virus.
In the present experiment, Pavlovian fear conditioning was adopted to study the effects of different early rearing environments on fear conditioning in adult rats. Weaned rats were reared in three manipulable environments (enriched, social and isolated conditions). After 8 weeks, fear conditioning (characterized by percentage of freezing) was observed and analyzed, and rats’ weight, locomoter activity and foot-shock sensitivity were operated too. The results showed that: (1) Compared with control group, the level of conditioned fear was significantly increased in enriched group, but significantly decreased in isolated group; (2) Enriched and isolated conditions influenced rat’s weight significantly; (3) Different rearing conditions have no effect on locomoter activity and foot-shock sensitivity. These results indicated that early enriched condition could improve the tone-evoked fear conditioning response, while isolated condition impaired the response.
Recent studies show that a reduced effect of inhibitory transmitter system in the visual cortex may underlie aged visual function degradation. Whether excitatory transmitter system changes with age and hence affects intracortical excitation-inhibition balance is not clear. To explore this issue, we used Nissl staining and immunohistochemical methods as well as Image-Pro Express software to examine the density of Nissl-stained neurons, Glutamic acid-immunoreactive (Glu-IR) neurons and γ-Aminobutyric acid-immunoreactive (GABA-IR) neurons in the primary visual cortex of young adult and aged cats. The results showed that there was no significant difference in the density of Nissl-stained neurons between young and old cats (P>0.05). However, the density of Glu-IR neurons and GABA-IR neurons in the primary visual cortex of aged cats was significantly lower than that of young ones (P<0.01). The ratio between Glu-IR neurons and GABA-IR neurons was significantly increased in old cats compared to that in young adult ones (P<0.01). These results indicated that the effect of excitatory transmitter system in the old visual cortex was increased relative to the inhibitory transmitter system, which might cause an imbalance between cortical excitation and inhibition and might be an important factor mediating the visual function decline during aging.
The W-3Bao mouse, which was obtained in previous ENU mutagenesis project, is a new mutant caused by the nonsense mutation of Kit gene. Mating and gross observing combining with PCR and sequencing were used for determining the genotypes of the W-3Bao mice. Embryonic development, hematological detection and histopathologic section methods were used for their phenotype analysis. The results showed that the W-3Bao/+ mouse was white belly, white limb terminals and white tail tip. However, there was no difference of the external appearance among the W-3Bao/+, W-3Bao/3Bao and wild type mice for the embryo of 12.5 days. The W-3Bao/3Bao embryos looked pale since pregnant 14.5 days and dwarf since pregnant 16.5 days. The extremely low level of haematochrome and big red blood cells of W-3Bao/3Bao 18.5-day-embryos were found in the inspections of blood routine items and blood smear, which resulted in death of W-3Bao/3Bao homozygous mouse around being born, and no live postnatal W-3Bao/3Bao mouse was found in this study. No spermatogonium at different developmental stages was found in some contorted seminiferous tubules in adult W-3Bao/+ mouse. At the age of 18.5-day embryo, the spermatogonium of W-3Bao/3Bao mice only lied in interstitial tissue and no one lied in contorted seminiferous tubules, while the spermatogonium of W-3Bao/+ or W+/+ mice lied in interstitial tissue and in contorted seminiferous tubules in the same time. At the age of 18.5-day embryo, cells arranged irregularly and primordial follicles were not seen in the W-3Bao/3Bao ovaries, while primordial follicles appeared clearly in the ovaries of W-3Bao/+ or W+/+ mice. We concluded that because of the nonsense mutation of Kit gene, the W-3Bao/+ mice show white spot and abnormal development of some contorted seminiferous tubules. The W-3Bao/3Bao mice die around birth resulting from severe macrocytic anemia and show abnormal genital glands of both genders.
In order to investigate the effects of age on androgen receptor (AR) in testes and epididymides of mandarin voles（Lasiopodomys mandarinus）, the expression of AR from five age groups [postnatal 1(neonatal), 10, 25, 45 and 60 days (adult) of age] was examined using immunohistochemistry method. The results were as follows: ① There was AR expression in leydig cells in neonatal voles and the expression of AR decreased at postnatal 10 days and 25days. AR expression reached its peak at postnatal 45 days and then decreased in adults（P＜0.05）. ② The positive expression of AR in myoid cells was found from neonatal to adult. The positive expression of AR was unchanged at postnatal 1 day and postnatal 10 days, but decreased at postnatal 25 days, reaching its highest level at postnatal 45 days and then decreased in adults (P＜0.05). ③ The positive expression of AR in prospermatogonia was weak in neonatal voles. There was no expression of AR in spermatogonia at postnatal 10 days. There was AR expression in spermatoon at postnatal 25 days, while in spermatocyte and some spermatoon at postnatal 45days. The positive expression of AR in spermatogonia, spermatoon and sperm was also found in adults. ④ The positive expression of AR in sertoli cells was found in adults, but there were few expressions of ARs at other ages. ⑤ The positive cells of ARs were both detected in epithelium cells and stroma cells of epididymides. These results suggest that AR expressiones in leydig cells, myoid cells and spermatogenic cells change significantly with mandarin vole’s individual development. Androgen facilitates leydig cells differentiation during puberty, and myoid cells play an important role during spermatogenesis. Androgen may regulate function of epididymises.
The sex pheromone blend of a China strain of the black cutworm moth Agrotis ypsilon (Rottemberg) (Lepidoptera: Noctuidae) was investigated. Chemical analysis of pheromone gland extracts of 3-day-old females showed that individual isolated glands contained only very small amounts of pheromone. The high-resolution gas chromatography combined with mass spectrometry (GC-MS) analysis showed the presence of Cis-7-dodecenyl acetate (Z7-12:Ac, A), Cis-9-tetradecenyl acetate (Z9-14:Ac, B), Cis-11-hexadecenyl acetate (Z11-16:Ac, C), Cis-8-dodecenyl acetate (Z8-12:Ac, E) and Cis-5-decenyl acetate (Z5-10:Ac, D) in biologically active pheromone gland extracts. An extract of one gland from a day 3 female gave the following values for the gland components: 0.245±0.098 ng for Z7-12:Ac, 0.080±0.031 ng for Z9-14:Ac, 0.089±0.033 ng for Z11-16:Ac, 0.085±0.031 ng for Z5-10:Ac, 0.105±0.065 ng for Z8-12:Ac per female. The percentages of Z7-12:Ac, Z9-14:Ac, Z11-16:Ac, Z5-10:Ac and Z8-12:Ac in pheromone gland extracts from individual females were (mean±SE) 40.451±13.66, 13.176±5.279, 14.943±5.142, 14.392±6.10 and 17.225±9.792 respectively, and the percentages of Z7-12:Ac, Z9-14:Ac and Z11-16:Ac were 58.75±9.429, 18.91±7.539 and 22.34±7.209. Field trials indicated that each single component of sex pheromone was non-effective and captured no males. The lures baited with duality compound of AB (3∶1) had a certain attraction to males, the mean captured number was 2.6. The attraction ability of the lures baited with ternary compound of ABC (3∶1∶1) to males added significantly, the mean captured number per trap was 7.40, which was 2.8 times of duality compound of AB (3∶1). The contents of sex pheromone could obviously affect its capture ability to males, the mean captured number was the highest at the dosage of 200 µg.
The yellow granules in the gastral cuticle of the Oriental hornet Vespa orientalis (Hymenoptera, Vespinae) are located in yellow stripes. In the present study, we focus on the micromorphology and formation of the yellow granules from their inception to their spread in the regions which are destined to acquire a yellow color. The cuticle was observed with several methods of electron microscopy. The results showed that the yellow granules comprise a layer which is 20-25 µm thick, within the total cuticular thickness of 40-45 µm. In the mentioned regions one can see, from above, many apertures of about 0.5 µm in diameter which extends into a peripheral photoreceptor cell. In each yellow granule, one discerns a myoid envelope inside which there are 9 fibrils arranged in a circle. Yellow granules maturation process involves infiltration of canals that give rise to the incipient ball-shaped primary granules which increase in number (as a result of continues budding off the walls of a canal) as the cuticle matures and transform into secondary barrel shaped granules, becoming elongated and then splitting into shorter barrels that fill up the entire area. Preliminary examinations have suggested liver-like function activity within the layer of yellow granules.
From October 2006 to May 2007, daily activity patterns and the relationship between time budget and age, wintering stage, flocking behavior of Black-necked Cranes were studied at Napa Lake Nature Reserve, Shangri-La of Yunnan Province. We compartmentalized the winter season into three stages based on the amount of change the Black-necked Crane habited on Napa Lake Nature Reserve. The statistics from test results show significant differences among different stages in foraging, vigilance, preening, resting, locomotion, aggression, and flying (F2,36= 4.63–26.54, c22= 5.29–13.68, P= 0.0016–0.000). During the study period, Black-necked cranes devoted most of their daily activity time to foraging , which is about 76.81±9.1％. The percent time spent foraging showed two peaks; one peaking in the middle morning and another higher peak during late afternoon. The postponing of higher foraging peaks is a behavioral adjustment in response to the frigid weather of morning. Adult Black-necked Cranes showed significant differences in foraging, vigilance and aggression between flocks and families（F1,76= 0.27, 0.77, U= 279, P= 0.001–0.000）, but there were no significant differences in juveniles（U=735–558, P=0.924–0.062）. Adults foraging in flocks showed an advantage for having more foraging time and less vigilance than family-based units. Juveniles spent more time in foraging and resting compared to adults, with less time in vigilance and aggression contrary. There are differences with wintering behavior between various wintering areas. We explain these activity changes as a consequence of a behavioral adaptation to the local environment changes, while climate and food resources are important factors that affect wintering behavior.
Operational sex ratio (OSR) is the ratio of the number of sexually mature males to the estrous females, which is used to predict the intensity of sexual selection. During the mating season (August－December 2007), we studied reproductive and aggressive behaviors in sexually mature male Tibetan macaques (Macaca thibitana) in two troops (YA1 and YA2) at Huangshan, China. The behavioral data were collected by focal animal sampling, ad libitum sampling and continuous recording. The purpose is to discuss the impact of OSR on mating competition of male Tibetan macaques. The OSR of YA1 was 0.4:1, and the OSR of YA2 was 0.9:1. The male-biased in OSR of YA2 was higher than YA1. The sexually mature males of high rank in YA1 troop showed higher rates of reproductive behaviors than the males in YA2: genital-inspecting, grimace, sexual chase and mating, respectively (P＜0.01). The sexually mature males of middle rank in YA1 troop showed higher rates of reproductive behaviors than the males in YA2: genital-inspecting, grimace, sexual chase (P＜0.01). The sexually mature males of middle rank in YA1 troop also showed higher rate of mating behavior than the males in YA2 (P＜0.05). However, there was no significant difference in reproductive behaviors between sexually mature males of low rank in two troops. The sexually mature males of high rank in YA2 troop showed higher rate of aggressive behavior than the males in YA1 (P＜0.01). The sexually mature males of middle rank in YA2 troop showed higher rate of aggressive behavior than the males in YA1 (P＜0.05). The sexually mature males of low rank in YA1 troop didn’t show any aggressive behavior. These results suggested that the intensification of male-biased in OSR can lead to the decrease of reproductive behaviors and the increase of aggressive behavior of male Tibetan macaques. The intensity of mating competition of sexually mature males in YA2 troop was stronger than the males in YA1. Our results support the prediction of the impact of OSR on mating competition by sexual selection theory.
Postnatal developments of morphological features (forearm and body mass) and vocalization (call frequencies and durations) of Rhinolophus pusillus were studied in the Jishui Cave of Guilin City from May 31st to July 20th 2006. The morphological changes indicated that infants of R. pusillus grew significantly in the postnatal three weeks and then gradually slowed down. Both forearm length and body weight were significantly correlated with the growing of age. Durations of infants’ calls were fairly variable and longer than those of adults. No significant correlation was found between the duration and age. Spectral characteristics indicated that the calls produced by infants had rather variable spectrums, unstable frequencies, and multiple harmonics in the first 20 days after birth. Infants over three weeks old mostly emitted FM-CF-FM type calls. Frequencies of first harmonics were significantly correlated with their age but the second harmonics did not correlate with age. The call frequencies of the young five-week-old bats were similar with their adults. The call frequency had a significant linear correlation with forearm length. Our findings indicated that the high flexible vocal cord and undeveloped nasal chamber might affect the vocalization veracity of new born infants.
Fourteen to sixteen specimens of Rana pleuraden (the numbers of male and female almost equal) were collected and dissected each month. Their snout-vent length, weight of body fat, spermary and ovary, volume of spermary, and diameter of oviducts were measured. The lengths of the snout-vents were analyzed by an ANOVA as a covariate factor. The results showed that there were significant differences in the weight of spermary and ovary, volume of spermary, and diameter of oviduct, which changed annually. The breeding season of R. pleuraden appeared from April to June and the breeding peak appeared from late May to early June. The analysis of allometric and regression showed that the growth of reproductive organs was mostly positive allometric (b>1) with snout-vent length or body weight. This meant that the growth of reproductive organs was substantially influenced by individual growth. The bigger individuals spawned at least twice per year, which was one of the reproductive strategies to enhance successful reproduction. The development of reproductive organs was negative allometric (b<1) to the weight of body fat. Body fat provided energy for reproduction and hibernation. Weight of body fat declined to the lowest point during the breeding peak. When less fat was deposited, a few individuals would delay hibernation in order to accumulate more energy to ensure safe living through the winter. The analysis of a Pearson correlation and cross correlation showed a significant correlation in the development of reproductive organs both in males and females. However, development of reproductive organs in males and females were not completely synchronic, and the spermary grew slowly because the maturation of eggs required longer time compared to sperm. Volume of spermary developed synchronously with diameter of oviduct, which was a good preparation for insemination.
The Dahe pig is one of the representative indigenous pig breeds in the middle-altitude region of southwest China, and has played an important role in the local meat production for a long time. In order to estimate the genetic variability in its population, as well as provide the guidance and basis of genetic background for its conservation and further utilization, 76 microsatellite loci situated on swine’s 19 chromosomes were analyzed for 60 individuals sampled from their natural population by employing PCR and polyacrylamide gel electrophoresis. A total of 347 alleles were detected and all the loci were polymorphic. The number of alleles varied from 3 to 10, with a mean allele and effective allele number of 4.57 and 3.50 at each locus respectively. The mean heterozygosity and polymorphism information content of 76 microsatellite loci were 0.696 2±0.071 6 and 0.644 1±0.091 4, respectively. The results indicated that the genetic diversity of the Dahe pig was rich, and the Dahe pig has a good selection potential for breeding.
A new recorded fish (Siniperca roulei) of the Yangtze estuary and Shanghai district was collected at the west end of Chongming Island in the survey on the intertidal fishes in May, 2008. It belongs to Family Serranidae of Order Perciformes. Its main features were described as the following: body slim and long, nearly tubby; head long and a little flat, and proboscis sharp; oral fissure big, the mandible apparent protruding, and the upper jaw outstretch to the area under the eye; ten thin sawteeth and two declining spurs at the rear edge and the ventrolateral edge of the front operculum, respectively; one flat spine at the back-end of the operculum with one short spine at its up-end; body tawny and some anomalistic macula and dark spots on the head and both sides of the body. Owing to the overfishing and water pollution, the resource amount of the fish has decreased sharply in recent decades. It has been listed in China Red Book of Endangered Animals. Currently, very few studies on this fish species have been carried out, especially those on their breeding, feeding and growing characteristics are even scare. Hence, it is extremely urgent to carry out the study and conservation on this species.