Prenatal Environmental Hypoxia Enhances Adult Hypoxia Tolerance in Brandt's Voles (Lasiopodomys brandtii): Behavioral and Transcriptomic Insights.

Brandt's vole (Lasiopodomys brandtii) is a hypoxia-tolerant species, and the metabolic characteristics of hypoxia-tolerant species have become a focus of recent research. However, insights into the anaerobic and aerobic metabolism of the livers of Brandt's voles under hypoxia remain limited. In this study, Brandt's voles and hypoxia-intolerant Kunming mice (Mus musculus, control species) were exposed to hypoxia conditions (Brandt's voles, 10% and 7.5% O2; Kunming mice, 10% O2) for 24 h, and changes in gene expression and enzyme activity related to anaerobic and aerobic metabolism in the livers were evaluated. Phosphofructokinase 1 (PFK1), phosphofructokinase 2 (PFK2), pyruvate kinase muscle (PKM), hexokinase 2 (HK2), and lactate dehydrogenase (LDH) related to anaerobic metabolism in the livers of Brandt's voles were increased under 7.5% O2. Regarding gene expression and enzyme activity for aerobic metabolism in Brandt's voles under 7.5% and 10% O2, pyruvate dehydrogenase kinase 1 (PDK1) expression was up-regulated, and succinate dehydrogenase (SDH) activity was decreased. In the livers of Kunming mice, gene expression related to anaerobic and aerobic metabolism was increased at the late stage of 10% O2, and SDH activity was enhanced at 6 h and reduced at 18 h. In addition, PFK1,PKM, PDK1 expression and SDH activity in Brandt's voles were significantly correlated with HIF-1a expression. PFK1, PKM, LDHand PDK1 expression in Kunming mice were significantly correlated with HIF-1a expression. These findings indicate that the livers of Brandt's voles have a certain tolerance to hypoxia, and metabolic changes play important roles in hypoxia tolerance.

Physiological indices and liver gene expression related to glucose supply in Brandt's vole (Lasiopodomys brandtii) exhibit species- and oxygen concentration-specific responses to hypoxia

内蒙古草原布氏田鼠与绵羊的营养生态位研究

Research on palatability of bait for targeted control of Brandt's vole (Lasiopodomys brandtii) in typical steppes

Rodents can cause considerable changes in plant community composition. However, relationships between shifts in species dominance and plant functional traits caused by rodents have seldom been investigated, especially for belowground functional traits. In this study, a set of enclosures was constructed to analyze the effects of 10 years of Brandt's voles' activities on the defense strategies and dominant position changes of three gramineous plants (Leymus chinensis, Stipa krylovii, and Cleistogenes squarrosa) in Inner Mongolia. Here, we measured the dominance, biomass, and fourteen functional traits of three plants. The effects of Brandt's voles on dominance, biomass, and functional traits were analyzed, and then we explored the effect of functional traits on plant dominance by using the structural equation model. Results showed that long-term feeding by Brandt's voles resulted in a significant decrease in the dominance of L. chinensis and S. krylovii, whereas C. squarrosa was positively affected. The belowground biomass of L. chinensis and S. krylovii was higher in the vole treatment, which showed that they were increasing their escape characteristics. The leaf thickness of L. chinensis and the leaf C:N ratio of S. krylovii significantly increased, while the specific leaf area of C. squarrosa significantly decreased. All three gramineous showed increased resistance traits in response to Brandt's voles, which positively affected their dominance. Tolerance-related traits of S. krylovii significantly increased, with the increasing growth rate of root length contributing to enhancing its dominance. We highlight that selective feeding by rodents led to the selection of different defense strategies by three gramineous plants, and that changes in biomass allocation and functional traits in the different species affected plant dominance, driving changes in the plant communities.

Diet of the Pallas's cat (Otocolobus manul) in Mongolian steppe habitat during a population peak of Brandt's voles

Multiple paternities increase genetic diversity of offspring in Brandt's voles

Cold commonly affects growth and reproductive development in small mammals. Here, we test the hypothesis that low ambient temperature will affect growth and puberty onset, associated with altered hypothalamic Kiss-1 gene expression and serum leptin concentration in wild rodents. Male Brandt's voles (Lasiopodomys brandtii) were exposed to cold (4 ± 1 °C) and warm (23 ± 1 °C) conditions from the birth and sacrificed on different developmental stages (day 26, day 40, day 60, and day 90, respectively). Brandt's voles increased the thermogenic capacity of brown adipose tissue, mobilized body fat, decreased serum leptin levels, and delayed the reproductive development especially on day 40 in the cold condition. They increased food intake to compensate for the high energy demands in the cold. The hypothalamic Kiss-1 gene expression on day 26 was decreased, associated with lower wet testis mass and testis testosterone concentration on day 40, in the cold-exposed voles compared to that in the warm. Serum leptin was positively correlated with body fat, testis mass, and testosterone concentration. These data suggested that cold exposure inhibited hypothalamic Kiss-1 gene expression during the early stage of development, decreased serum leptin concentration, and delayed reproductive development in male Brandt's voles.

Re-feeding evokes reproductive overcompensation of food-restricted Brandt's voles

Inbreeding depression is a major evolutionary and ecological force influencing population dynamics and the evolution of inbreeding-avoidance traits such as mating systems and dispersal. Mating systems and dispersal are fundamental determinants of population genetic structure. Resolving the relationships among genetic structure, seasonal breeding-related mating systems and dispersal will facilitate our understanding of the evolution of inbreeding avoidance. The goals of this study were as follows: (i) to determine whether females actively avoided mating with relatives in a group-living rodent species, Brandt’s voles (Lasiopodomys brandtii), by combined analysis of their mating system, dispersal and genetic structure; and (ii) to analyze the relationships among the variation in fine-genetic structure, inbreeding avoidance, season-dependent mating strategies and individual dispersal. Using both individual- and population-level analyses, we found that the majority of Brandt’s vole groups consisted of close relatives. However, both group-specific FISs, an inbreeding coefficient that expresses the expected percentage rate of homozygosity arising from a given breeding system, and relatedness of mates showed no sign of inbreeding. Using group pedigrees and paternity analysis, we show that the mating system of Brandt’s voles consists of a type of polygyny for males and extra-group polyandry for females, which may decrease inbreeding by increasing the frequency of mating among distantly-related individuals. The consistent variation in within-group relatedness, among-group relatedness and fine-scale genetic structures was mostly due to dispersal, which primarily occurred during the breeding season. Biologically relevant variation in the fine-scale genetic structure suggests that dispersal during the mating season may be a strategy to avoid inbreeding and drive the polygynous and extra-group polyandrous mating system of this species.

Molecular cloning and characterization of kiss1 in Brandt's voles (Lasiopodomys brandtii).

Objective To determine a method for amplification of cytochrome C oxidase subunit I(CO I) gene of Brandt's vole. Methods The Brandt's Voles were captured in Abagaqi Xilingol League Inner Mongolia, and DNA was extracted from liver tissue. CO I gene was amplified by nested PCR and sequenced afterwards. Results A band of 657 bp and 1 132 bp was amplified by internal and external PCR primers, respectively, which were consistent with expected sizes. A total of 12 segments of Brandt's Vole CO I gene sequences were amplified by PCR and verified by sequencing. The sequence number was KF182196 - KF182207 in GenBank. After gene sequence alignment of the 12 CO I gene sequences, it was found that the similarity was 100%, and no base mutation. Conclusion CO I gene of Brandt's Vole could be amplified by nested PCR without pseudo gene. Key words: Nested PCR; Brandt's Vole; Cytochrome C oxidase subunit I gene

ABSTRACTBrandt's voles have an annual cycle of body weight and adiposity. These changes can be induced in the laboratory by manipulation of photoperiod. In the present study, male captive-bred Brandt's voles aged 35 days were acclimated to a short day (SD) photoperiod (8L:16D) for 70 days. A subgroup of individuals (n=16) were implanted with transmitters to monitor physical activity and body temperature. They were then randomly allocated into long day (LD=16L:8D) (n=19, 8 with transmitters) and SD (n=18, 8 with transmitters) groups for an additional 70 days. We monitored aspects of energy balance, glucose and insulin tolerance (GTT and ITT), body composition and organ fat content after exposure to the different photoperiods. LD voles increased in weight for 35 days and then re-established stability at a higher level. At the end of the experiment LD-exposed voles had greater white adipose tissue mass than SD voles (P=0.003). During weight gain they did not differ in their food intake or digestive efficiency; however, daily energy expenditure was significantly reduced in the LD compared with SD animals (ANCOVA, P<0.05) and there was a trend to reduced resting metabolic rate RMR (P=0.075). Physical activity levels were unchanged. Despite different levels of fat storage, the GTT and ITT responses of SD and LD voles were not significantly different, and these traits were not correlated to body fatness. Hence, the photoperiod-induced obesity was independent on disruptions to glucose homeostasis, indicating a potential adaptive decoupling of these states in evolutionary time. Fat content in both the liver and muscle showed no significant difference between LD and SD animals. How voles overcome the common negative aspects of fat storage might make them a useful model for understanding the phenomenon of ‘healthy obesity’.

Diet-induced obesity in the short-day-lean Brandt's vole

Age structure and seasonality influence the population fluctuations of small rodents. Age determines body weight and social experience, while seasonality regulates the duration of the breeding season and onset of sexual maturity in newborn offspring. Therefore, reproductive success and skew usually occur in different age groups. Brandt's vole (Lasiopodomys brandtii) is a social, short-lived and seasonal breeding small rodent with a dramatic seasonal population fluctuation, but reproductive skew is not fully understood in this species. In the present study, we determined kinship in semi-natural enclosure populations using microsatellite markers based on genotyping, analyzed the reproductive skew between sexes and between overwintered and newborn voles, and monitored variation in male reproductive activity by testing fecal testosterone levels throughout the year. Overwintered voles had the most reproductive success along with a striking increase in the population size in the enclosures, with all biological fathers and 77.8% of biological mothers, which had 100% and 87% of the total offspring, respectively. Compared to overwintered voles, reproductive skews were significantly higher in potential overwintered and newborn parents, implying the possible reproductive suppression of newborn voles by dominant overwintered voles. Moreover, both heavier body weight and higher testosterone levels in overwintered males supported their potential social status in the population. Our study provided new evidence for reproductive skew and differentiation of postnatal gonadal development patterns of different age groups in Brandt's vole.