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Climate warming and human disturbance are known to be key drivers in causing range contraction of many species, but quantitative assessment on their distinctive and interactive effects on local disappearance is still rare.In this study, we examined the association of climate warming and human disturbance stressors with local disappearance probability of Brandt's voles (

We studied the infectious effect of SARS-CoV virus on juvenile and adult Brandt’s Vole (Microtus brandtii) by nasal cavity spraying method (CCID50 is 105.7). SARS virus caused serious deaths in adults. The death adults demonstrated hemorrhage from mouth, nasal cavity and intestine, hemorrhageious interstitial pneumonia and gore in liver, spleen and kidney. The survival adults demonstrated local hemorrhagic spot in lung and emphysema, but the other organs showed no pathological abnormality. SARS virus caused no deaths in juveniles, but locomotion of infected juveniles became slower. In the early stage, there was local pneumonia in lung and SARS viruses were isolated from the pathological tissue. Only one control juvenile lived and the infected juvenile showed local pneumonia in lung. The results demonstrated that SARS-CoV infected Brandt’s vole seriously and adults were more susceptive to SARS-CoV than juveniles. The Brandt’s vole may be a potential animal model for SARS research.

Background The colonial habit of Brandt’s vole (Lasiopodomys brandtii) differs from that of most other species of the genus Microtus. The demographic history of this species and the patterns shaping its current genetic structure remain unknown. Here, we explored patterns of genetic differentiation and infered the demographic history of Brandt’s vole populations through analyses of nuclear microsatellite and D-loop sequences. Results Phylogenetic analyses divided the sampled populations into three main clusters, which represent the southeastern, northeastern and western parts of the total range in Mongolia and China. Molecular data revealed an ancestral area located in the southeast of the extant range, in the Xilinguole District, Inner Mongolia, China, from where Brandt’s vole populations began expanding. A gene flow analysis suggested that the most likely colonization route was from the ancestral area and was followed by subsequent northeastward and westward range expansions. We identified decreases in genetic diversity with increasing distance from the founder population within the newly occupied regions (northeastern and western regions), clinal patterns in the allele frequencies, alleles that were rare in the original area that have become common in the newly occupied regions, and higher genetic differentiation in the expanded range compared with the original one. Conclusion Our results indicate that L. brandtii most likely originated from the southeastern part of its current geographic range, and subsequently colonized into the northeastern and western parts by expansion. The genetic patterns among the derived populations and with respect to the original population are consistent with that expected under genetic surfing models, which indicated that genetic drift, rather than gene flow, is the predominant factor underlying the genetic structure of expanding Brandt’s vole populations. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0995-y) contains supplementary material, which is available to authorized users.

Sampling information for Brandt’s vole. Table S2. Summary statistics for twelve microsatellite loci over all Brandt’s vole samples. Table S3. Genetic diversity measures calculated over 12 microsatellite loci and across all geographic locations. Table S4. Summary of Chi-Square Tests for Hardy-Weinberg Equilibrium for each geographic location sampled. Table S5. Geographic occurrences and frequencies of D-loop haplotypes H1–30. Table S6. Summary statistics on polymorphism and demographics inferred from analyses of D-loop sequences. Table S7. Pairwise F ST values calculated based on microsatellite data between 23 geographic locations sampled. Table S8. Clades support and ancestral areas reconstruction as obtained with S-DIVA and Lagrange. (DOCX 115 kb)

Brandt’s vole population structure based on 12 microsatellites loci as implemented by STRUCTURE. A) Values of lnP(D) from 20 independent runs for K = 1–23. B) Values of ΔK from 20 independent runs plotted for K = 1–23 and calculated by the Evanno method. (PDF 3121 kb)

In the approaching tracking process, we get infrared images from far to near, and the target in the images varies from small to big. The main problems in the tracking process are the large variety of scale, the change of target’s posture and intensity, the collusion of interferences. This paper focuses on the whole tracking and detection process when the target and inferences exist at the same time and block each other. We propose an approach which includes several cues. Firstly, according to the amount of target pixels, the target is divided into small target and shaped target. Then we use the information of the target displacement rate to track and detect the small target which only has several pixels and is unstable. For the shaped target, we can make use of the target’s contrast information. Lastly, we validate our method by designing an experiment which simulates the entire tracking and detection process. The test shows that our method improve the performance.

The current study evaluated effects of quinestrol on oxidative stress and abnormal spermatogenesis for male Mongolian gerbils. Gerbils were randomly divided into multi-dose treated, single-dose treated, control groups. At 15 days after treatment antioxidant enzymes (SOD, GSH-Px) activities and T-AOC were decreased whereas the MDA concentration was significantly increased, testicular weight and seminiferous tubular areas decreased, germ cells were rarefied and showed irregular distribution in seminiferous tubules, apoptosis was pronounced among spermatocytes and spermatids, the number of dead and abnormal acrosomes of spermatozoa increased significantly in quinestrol treated groups. At 30 days following treatment the testicular histopathological changes were more severe, sperm quality and antioxidant capacity continued to decline, and multi-dose treatment produced more damage to gerbils testes compared with single-dose treatment. The physiological indicators were recovered by 60 days of treatment withdrawal. The results showed oxidative stress induced by quinestrol in relation to abnormal spermatogenesis.

Brandt’s vole (Lasiopodomys brandtii) distribution is discontinuous in Inner Mongolia with some populations isolated from others. Recently, some isolated populations have suffered extinction, and the factors responsible remain elusive. Genetic drift is one of the processes affecting population genetic differentiation, and can play a substantial role in the divergence of small, isolated populations. Using seven microsatellite markers, we genotyped four geographically isolated populations of Brandt’s vole, all of which exhibit episodic fluctuations in population density. The results showed a strong genetic differentiation among the geographically distinct populations (total F ST = 0.124) and in particular, one population (Zhengxiangbaiqi) was isolated from all others (F ST values were greatest between Zhengxiangbaiqi and other populations). Furthermore, high levels of inbreeding (F IS values ranged from 0.205 to 0.290) within each distinct population suggest that inbreeding has and is likely occurring in Brandt’s vole populations. These processes can decrease average individual fitness and consequently increase the risk of extinction of the species.

Effects of sasanguasaponin (SGS), a compound from defatted seeds of Camellia oleifera, on abnormal spermatogenesis were studied in adult male mice using daily intragastric administration of 100, 200 and 400 mg/kg body weight (BW) for 6 weeks. The sperm counts decreased and the number of abnormal spermatozoa increased in mice treated with SGS at 400 mg/kg dose level. Testicular weight and seminiferous tubular area gradually decreased as dosage increased to 400 mg/kg SGS. Germ cells were rarefied and showed irregular distribution in seminiferous tubules (STs). Apoptosis was pronounced among spermatocytes and spermatids at the 400 mg/kg dose level. Antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and total antioxide capacity (T-AOC) markedly decreased and malondialdehyde (MDA) concentration increased in the testes. These results suggest that adult exposure to SGS (400 mg/kg) induces spermatogenic apoptosis through increased oxidative stress in male mice.

Using a laboratory colony we demonstrated that the body mass (BM) and reproductive organ mass (ROM) of Brandt's voles vary in response to photoperiod and temperature. Male Brandt's voles from 25 days of age were housed under long (14L) or short (10L) photoperiod, which corresponds to seasonal changes in their natural environment. Under 10L, animals housed for the first 7 weeks at 10°C were significantly lighter than those housed at 20°C. This effect was not observed under 14L. However, a change from an initial 10L photoperiod to the 14L photoperiod for the following 9 weeks could compensate the effects of low temperature on BM. Changes in BM in response to photoperiod and/or temperature exposure appeared to be primarily as a result of the deposition or loss of fat-free dry mass and water. For Brandt's voles, ROM was regulated significantly by photoperiod but not by temperature. Taken together, the results suggest that BM and ROM for male Brandt's voles respond selectively to photoperiodic information and temperature. We propose that a compensatory relationship between photoperiod and temperature should be considered in animal physiology research.

Levonorgestrel and quinestrol, commonly known as EP-1, has long been used in the control of wild rodents. Up to the present time, however, no method for simultaneous quantification of levonorgestrel and quinestrol in rat plasma has been reported. In the present study, a sensitive reverse-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC-UV) method for quantification of levonorgestrel and quinestrol in rat plasma has been developed. It uses a Kromasil ODS C(18) column and acetonitrile-0.1% formic acid (85 : 15, v/v) mobile phase at ambient temperature. The plasma sample was prepared by hexane-isoamyl alcohol extraction (90 : 10, v/v). The flow rate and detection wavelength were 1.0 mL/min and 230 nm. The correlation coefficients were greater than 0.9995 within 0.08-50 microg/mL for levonorgestrel and 0.12-50 microg/mL for quinestrol, and the limits of detection were 0.02 and 0.05 microg/mL for levonorgestrel and quinestrol, respectively. Average recovery ranged from 92.5 to 96.3% and inter-day RSDs were less than 7.56%. This method can be applied to the further pharmacokinetic study of levonorgestrel and quinestrol in rat plasma.

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Brandt's voles (Microtus brandti) are small native mammals that inhabit the grasslands of Inner Mongolia, China. The species is considered a pest, particularly during population outbreaks, which have increased in frequency since 1970 from 1 every 7 years to 1 every 3 to 5 years. Using historical records taken between 1948 and 1998, we found that there was significant correlation between years for which the monthly averages of the Southern Oscillation Index (SOI) were consistently high, and years in which outbreaks occurred. Also there was a tendency for outbreaks not to occur in years with precipitation above or below average. For some years at some sites, annual or biannual estimates are available for the density of Brandt's vole populations. We found that the seasonal rate of increase over the non-breeding season from autumn to spring was negatively correlated with the density in autumn. The rate of increase over the breeding season from spring to autumn was independent of the density in spring but instead, reflects the species' preference for habitat with short, sparse grass; populations do not persist in highly degraded grasslands or in tall, dense grassland. The link between outbreaks and climatic indices, and the numerical response of Brandt's voles to particular habitat characteristics, suggest that current grazing intensity tends to maintain grass at low height in years with average precipitation. The substantial increase in livestock numbers over the last 50 years appears to have increased the number of years when the balance of grazing and plant growth favours high rates of increase in Brandt's vole populations, and hence, there has been an increase in the frequency of outbreaks.

Summary 1 Brandt’s vole Microtus brandti is considered a pest in China and is actively managed through the use of toxic baits. A time-dependent density-dependent Leslie matrix model was developed to investigate the effectiveness of fertility control as an alternative. 2 Three annual cycles of Brandt’s vole were observed between 1995 and 1998 at a site in the grasslands of Inner Mongolia, China. For each of these cycles, cohort-specific monthly survival rates were derived for the spring, summer and autumn months. Over the breeding season, monthly reproductive rates were obtained as numbers of young females per adult female. 3 Survival of voles over winter, a 5–6-month period, depended on age at the onset of winter and the density in autumn. 4 The model was parameterized with measured and continuously varying monthly data for vital rates. It was then used to predict the impact that fertility control, delivered with non-toxic baits, and lethal control would have had on the vole population if control had been imposed in the autumn of 1994 or spring of 1995. The timing and frequency of bait delivery were varied, and we considered the population response to bait that renders females sterile and bait that renders females only temporarily infertile. 5 The model suggested that the effectiveness of lethal control in spring could be matched by fertility control if it was applied twice in the spring of a year in which high densities were reached, or in the previous autumn. The latter requires that (i) infertility is long-lasting in treated animals and (ii) either high-density years be reliably forecast a year ahead or fertility control be applied every autumn. 6 Brandt’s voles provide an exception to the general rule that fertility control is never more effective than lethal control applied at the same time with the same bait uptake. We found that when control was applied in autumn, fertility control was better than lethal control in reducing the numbers of voles over the following spring, summer and autumn. This is because normal density-dependent mortality over winter has a greater impact following fertility control than lethal control.

Ten polymorphic microsatellite loci from Lasiopodomys brandtii have been isolated and characterized. Two to 11 alleles per locus were detected from 52 Brandt's voles samples collected from a single population. Expected heterozygosities ranged from 0.406 to 0.840. For the majority of loci observed heterozygosities were similar to or greater than the expected heterozygosity. One locus pair appeared to be in linkage disequilibrium. The microsatellite markers will enable the studies of genetic diversity, population structure and relatedness in this species, and perhaps in closely related species of vole.

How to distinguish mental healthy people from people suffered from depression objectively is an unsolved question in both pattern recognition and clinical psychology. Traditional diagnosis of depression was drawn by doctors according to the results of questionnaire analysis or scale tests, which were prone to be subjective. In this paper, we selected negative and positive scenes from IAPS as the background, positive and negative faces from Taiwanese Facial Expression Image Database as foreground. Based on the competing effect and the priming effect of background scenes, we designed two experiments by controlling the relative appearing orders of background scenes and foreground faces. By recording subjects’ response times at key-strokes, we quantified the identification differences towards different combinations of background and foreground between depressed people and mental healthy people, and these quantified differences can be used as criteria to derive features distinguishing two kinds of people objectively.

Rodent pest population outbreaks occur frequently in grassland ecosystems in northern China. The Mongolian gerbil (Meriones unguiculatus) is a dominant pest rodent which is distributed across the semi-desert grasslands of Inner Mongolia, China. In 2009, we studied the contraceptive effect of levonorgestrel-quinestrol (EP-1), concentration 50 ppm, on a wild Mongolian gerbil population. The one-off contraceptive treatment was compared with a control group using a semi-monthly live trapping method in the Ordos Semi-desert Grassland Region of Inner Mongolia. The results show that juveniles were not recruited in spring in the treatment group. Ratios of juveniles in the control and treatment groups showed significant semi-monthly differences from spring to summer (one-way ANOVA, F2, 14 = 7.53, P < 0.05). Between both groups, annual fluctuations of juvenile and total population densities were significantly different respectively (F2, 14 = 4.64, P < 0.05; F2, 18 = 7.72, P < 0.05). The contraceptive EP-1 delayed the normal reproductive pattern of Mongolian gerbil populations. This suppressed birth rates of gerbil populations, reduced their densities, and changed their age structures. The period of EP-1 baiting should be extended but it could be an ideal method for controlling Mongolian gerbil populations during each breeding season.

Fertility control has been identified by studies in the laboratory and the field as a more appropriate and long-term control strategy for rodent pests than lethal control. In this study, we investigated the effects of quinestrol on mass of reproductive organs and on social behaviors in female and male Indochinese forest rat (Rattus andamanensis (Blyth, 1860)] using approach of morphometrics and genetics). [corrected]. A total of 16 adult females and 16 adult males were randomly assigned to 4 groups. One male and one female group were fed rice with 0.005% quinestrol by weight for 7 days, and another 2 groups were fed rice only. After 7 days, rats were assigned to 10 min dyadic encounters between groups, and investigation, aggression, defense and attack latency were quantified. All animals were killed on day 10, and reproductive organs were dissected and weighed. Dyadic encounter data showed that there were obvious changes in social behaviors of quinestrol-treated rats. Quinestrol significantly inhibited the investigative behavior of quinestrol-treated males toward control females in Rattus nitidus, but seldom affected investigation between control males and quinestrol-treated females. Aggression of control females toward quinestrol-treated males was higher than that of quinestrol-treated females, and defense of quinestrol-treated males toward control females was more remarkable than that of control males. Quinestrol remarkably decreased wet masses of epididymis and spermotophore in males and ovaries in females, but had no effect on wet masses of testes and uteri after quinestrol treatment. These results indicate that the anti-fertility effects of quinestrol on R. nitidus are attributed to not only suppressing reproductive organs but also impacting social behaviors associated with territory defense and mate choice.

In natural conditions, animals have to cope with fluctuations of food resources. Animals having experienced prolonged decrease in feeding opportunities may increase their reproductive success when meeting abundant food. Though food restriction is well known to reduce reproductive success of animals, it is not clear whether re-feeding can restore or even overcompensate the reproductive success. In this study, we investigated the differences in reproductive parameters between food-restricted and refed (FR-RF) group and control group of Brandt's vole (Lasiopodomys brandtii). For 4 weeks, FR-RF voles were provided with 70% of their normal daily food intake and then they were fed ad libitum for the next 4 weeks. Voles of control group were fed ad libitum for 8 weeks. Females (FR-RF or control) were mated to non-littermate males of the same group (FR-RF or control), and we found that the mean litter size and survival rate of F1 pups of FR-RF group were significantly higher than those of control group. We also provided a field example showing that the litter size of Brandt's voles tended to be higher if they experienced two consecutive dry and wet months than that of voles didn't have this experience. Our results suggest that re-feeding may have evoked an overcompensatory mechanism of food-restricted voles in reproductive success. This may be an adaptive strategy for Brandt's voles (with oscillating populations) to cope with the fluctuating food resources in natural conditions by adjusting their reproductive success.

To meet the demands of monitoring and controlling of pest rodents in rural areas in China, the information system for rodent monitoring in rural areas was designed and developed. The system includes three sub-systems: data collection software on the basis of PDA +GPS, information management system, and information query system for rodent spatial distributing characteristics based on WebGIS. The data collecting software, consists of 2 modules (Night Trapping Method module and Valid Holes Method module), can be used to record pest rodents field- monitoring data binding with position data and transfer the data to the database as main data source of the system. The information management system can manage the data recorded by PDA and provide data for WebGIS system. The information query system can provide various spatial distribution characteristics of pest rodents to users and assist users to primarily determine pest rodents' trends by a multi-criteria query function. The system is integrated with the data recording, transferring, managing, and providing information query services. It laid the foundation for further pest rodents' prediction and forecast in rural areas in China.

Effects of diethylstilbestrol (DES), an endocrine disrupting chemical, on abnormal spermatogenesis were studied in adult hamster using daily subcutaneous injection of 0.01, 0.1 and 1.0 mg/kg body weight for 1 week. Testicular weight and seminiferous tubular area gradually decreased as dosage increased to 1.0 mg/kg DES. Germ cells were rarefied and showed irregular distribution in seminiferous tubules. Apoptosis was pronounced among spermatocytes and spermatids at the 1.0 mg/kg dose level. Antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and total antioxide capacity (T-AOC) markedly decreased and malondialdehyde (MDA) concentration significantly increased in the testes. These results suggest that DES (1.0 mg/kg) induces testicular oxidative stress and spermatogenic apoptosis in adult male hamsters to extend findings shown for prenatal and/or neonatal exposure.