Cricetulus Barabensis Research Articles

Identification and characterization of a novel rodent bocavirus from different rodent species in China

Members in the genus Bocaparvovirus are closely related to human health and have a wide host range. The diverse hosts raise the possibility of crossing species barrier, which is a feature of emerging viruses. Among the mammalian hosts, rodents are generally acknowledged to be important reservoirs of emerging viruses. Here, rodent samples collected from six provinces and autonomous regions of China (Liaoning, Inner Mongolia, Tibet, Xinjiang, Guangxi and Yunnan) were used to investigate the prevalence and distribution of bocaparvoviruses. By using next-generation sequencing first, a partial non-structural protein 1 (NS1) gene belonging to a possible novel bocaparvovirus was discovered. Following this, PCR-based screening of NS1 gene was conducted in 485 rodent samples, with 106 positive results found in seven rodent species (Rattus norvegicus, Mus musculus, Apodemus agrarius, Cricetulus barabensis, Rattus flavipectus, Rattus rattus and Rhombomys opimus). Finally, six nearly full-length genomes and three complete CDS were obtained and the newly identified bocaparvovirus was tentatively named rodent bocavirus (RoBoV). RoBoV has three ORFs: NS1, NP1, and VP, which are characteristics of bocaparvoviruses. Phylogenetic analyses revealed that porcine bocavirus isolate PBoV-KU14, a member of Ungulate bocaparvovirus 4, was the most related virus to RoBoV, with 92.1–92.9% amino acid identities in NS1 protein. Alignments of RoBoV-related sequences showed RoBoV isolates could be classified into two clades, demonstrating an inter-host genetic diversity. The results indicate a potential interspecies transmission of RoBoV between rodents and swine and expand our knowledge on bocaparvoviruses in rodent populations.

Seasonal variations in cellular and humoral immunity in male striped hamsters (Cricetulus barabensis).

ABSTRACTAnimals in the non-tropical zone usually demonstrate seasonal variations in immune function, which is important for their survival. In the present study, seasonal changes in immunity in striped hamsters (Cricetulus barabensis) were investigated to test the winter immunoenhancement hypothesis. Male hamsters were captured from the wild in the fall and winter of 2014 and in the spring and summer of 2015. Body mass, body fat mass and blood glucose levels of the hamsters were all highest in the summer, whereas relative fatness and thymus mass had no seasonal changes. Spleen mass was highest in the fall and white blood cells and phytohaemagglutinin (PHA) response indicative of cellular immunity were lowest in the summer among the four seasons, which supports the winter immunoenhancement hypothesis. IgG and IgM titers were lowest in the fall, which was against this hypothesis. Body fat mass had no correlations with cellular and humoral immunity, suggesting it was not the reason for seasonal changes in cellular and humoral immunity in males. Leptin titers were higher in spring and summer than in fall and winter. No correlation between leptin and cellular and humoral immunity suggested that leptin did not mediate their seasonal changes. Similarly, corticosterone levels were also higher in spring and summer than in fall and winter, which correlated negatively with cellular immunity but positively with IgG levels. This result implied that corticosterone has a suppressive effect on cellular immunity and an enhancing effect on humoral immunity. In summary, distinct components of immune systems exhibited different seasonal patterns. This article has an associated First Person interview with the first author of the paper.

Strategies of behavior, energetic and thermogenesis of striped hamsters in response to food deprivation.

The life history of many animals includes periods of food shortage. Two behavioral strategies are involved in small mammals in response to food shortage: an increase in activity behavior, representing the increased foraging or migratory behavior, and a decrease in activity level, serving as a mechanism for conserving energy. However, it is uncertain whether animals adopt both strategies in response to food shortage, and whether hormone and neuroendocrine mechanisms are involved in both strategies. In the present study, changes in behavior and metabolic rate were examined in food-deprived striped hamsters (Cricetulus barabensis). The effects of leptin supplement on activity behavior, metabolic rate and hypothalamic neuropeptide gene expression were also examined. The behavior of food-deprived hamsters significantly changed with photoperiod phases: with increasing activity during the dark phase compared to those fed ad libitum, whereas decreasing activity and simultaneously increasing resting behavior during the light phase. Resting metabolic rate, body mass, and masses of fat depots and digestive tracts significantly decreased in food-deprived hamsters compared with ad libitum controls. Leptin supplement tended to attenuate the increased activity in the dark phase. Gene expression of hypothalamic neuropeptide Y (NPY) was significantly upregulated in food-deprived hamsters, while was significantly attenuated by exogenous leptin. These findings suggest that both behavior strategies are important behavioral adjustments in free-living animals to cope with food shortage. Leptin and hypothalamic NPY gene expression may be involved in the adjustments of physiology and behavior in animals demonstrating a hyperactivity strategy in response to food shortage.

Effect of temperature and food restriction on immune function in striped hamsters (Cricetulus barabensis).

Small mammals in temperate areas face seasonal fluctuations of temperature and food availability, both of which may influence their immune responses, which are critical to survival. In the present study, we tested the hypothesis that low temperature and food restriction suppress immune function in striped hamsters (Cricetulus barabensis). Thirty-seven adult male hamsters were randomly assigned to warm (23±1°C) and cold (5±1°C) treatment groups, which were further divided into fed and food-restricted groups. Body mass was not affected by cold stress, food restriction or the interaction cold stress×food restriction. Cold stress decreased total body fat mass, haematological parameters including white blood cells, lymphocytes and neutrophilic granulocytes, and immunoglobin (Ig) M titres 5 days after injecting keyhole limpet haemocyanin (KLH). However, cold temperature increased bacterial killing capacity, indicative of innate immunity, and did not affect the mass of the thymus and spleen, intermediate granulocytes, the phytohaemagglutinin (PHA) response and the levels of blood glucose and serum leptin. Corticosterone concentration was affected significantly by the interaction cold stress×food restriction but not by cold stress or food restriction alone. Food restriction reduced thymus mass, but other immunological parameters including body fat mass, spleen mass, haematological parameters, innate immunity, PHA response, the titres of IgM and IgG, and the levels of blood glucose and serum leptin were all not affected by food restriction or the interaction cold stress×food restriction. Innate immunity was positively correlated with leptin levels, whereas no significant correlations were observed in the levels of blood glucose, serum leptin, corticosterone and all the detected immune parameters. Our results show that cold stress suppressed humoral immunity but enhanced innate immunity and did not affect cellular immunity in striped hamsters. Most immunological indices were not influenced by food restriction. Blood glucose, leptin and corticosterone could not explain the changes of innate, cellular and humoral immunity upon cold stress or food restriction in striped hamsters.

Microsatellite loci variation and investigation of gene flow between two karyoforms of Cricetulus barabensis sensu lato (Rodentia, Cricetidae)

We examine the diversity of six microsatellite loci and partial RAG1 exon of “barabensis” and “pseudogriseus” karyoforms in Cricetulus barabensis sensu lato species complex. A total of 435 specimens from 68 localities ranging from Altai to the Far East are investigated. The results of the population structure analysis (factor analysis and NJ tree based on Nei genetic distances) support subdivision into two well-differentiated clusters corresponding to the two karyoforms. These karyoforms are also well differentiated by the level of microsatellite variability. In several “barabensis” specimens, we found microsatellite alleles that are common in “pseudogriseus” populations but are otherwise absent in “barabensis.” Most of these specimens originate from a single population in one of the zones of potential contact between karyoforms, Kharkhorin in Central Mongolia. These molecular results are consistent with previously published karyological data in suggesting that rare hybridization events between the two chromosomal races occur in nature.

Photoperiod and temperature differently affect immune function in striped hamsters (Cricetulus barabensis)

Small mammals generally use short day length to elevate immune function to counteract the immunosuppressive effect of low temperature in winter in light of the winter immunoenhancement hypothesis. In the present study, we tested this hypothesis in striped hamsters (Cricetulus barabensis). We expected that immune responses would be increased by short photoperiod but suppressed by low temperature.Thirty-four adult female hamsters were randomly divided into the long day (16L:8D) and short day (8L:16D) groups, which were further assigned into the warm (23±1°C) and the cold (5±1°C) groups, respectively. We found that body mass was not affected by photoperiod or temperature. Contrary to our expectation, short day reduced phytohaemagglutinin (PHA) response indicative of cellular immunity and the levels of immunoglobin (Ig) M. It had no effect on total body fat mass, thymus and spleen masses, white blood cells (WBC) and Ig G titers. As expected, cold stress decreased total body fat mass, WBC, Ig G and Ig M titers. However, it did not influence the masses of thymus and spleen and PHA responses. The levels of blood glucose, serum leptin and corticosterone were all not affected by temperature or photoperiod except that corticosterone levels were increased by short days. No significant correlations were detected among the levels of blood glucose, serum leptin, corticosterone and all the detected immunological parameters. Taken together, short photoperiod suppressed both cellular and humoral immunity in striped hamsters, which did not support the winter immunoenhancement hypothesis. Cold stress reduced humoral immunity and WBC, which might account for the highest mortality in winter in this species. Blood glucose, leptin and corticosterone could not interpret the changes of immunity in hamsters.

Food restriction attenuates oxidative stress in brown adipose tissue of striped hamsters acclimated to a warm temperature

It has been suggested that the up-regulation of uncoupling proteins (UCPs) decreases reactive oxygen species (ROS) production, in which case there should be a negative relationship between UCPs expression and ROS levels. In this study, the effects of temperature and food restriction on ROS levels and metabolic rate, UCP1 mRNA expression and antioxidant levels were examined in the brown adipose tissue (BAT) of the striped hamsters (Cricetulus barabensis). The metabolic rate and food intake of hamsters which had been restricted to 80% of ad libitum food intake, and acclimated to a warm temperature (30°C), decreased significantly compared to a control group. Hydrogen peroxide (H2O2) levels were 42.9% lower in food restricted hamsters than in the control. Malonadialdehyde (MDA) levels of hamsters acclimated to 30°C that were fed ad libitum were significantly higher than those of the control group, but 60.1% lower than hamsters that had been acclimated to the same temperature but subject to food restriction. There were significantly positive correlations between H2O2 and, MDA levels, catalase activity, and total antioxidant capacity. Cytochrome c oxidase activity and UCP1 mRNA expression significantly decreased in food restricted hamsters compared to the control. These results suggest that warmer temperatures increase oxidative stress in BAT by causing the down-regulation of UCP1 expression and decreased antioxidant activity, but food restriction may attenuate the effects.

Spatial niche partitioning of coexisting small mammals in sand dunes

Resource partitioning may allow species coexistence. Sand dunes in the typical steppe of Inner Mongolia, China, consist of desert, shrub and grass habitats, providing an appropriate system for studies of spatial niche partitioning among small mammals. We collected data to verify the niche separation hypothesis that coexisting small mammals would separate into spatial niches, and the productivity hypothesis that the highest species richness and overlap were to be expected in the most productive and diverse shrub habitat of the north-facing slopes, in contrast with the less productive grass and desert habitats of sand dunes. We trapped small mammals on 44 sand dunes in the summer of 1984 using snap traps. We captured 12 species of small mammals among three types of habitats. Cricetulus barabensis was a habitat generalist, present in all three types of habitats. Spermophilus dauricus was present only in the grass habitat, Allactaga sibirica and Dipus sagitta only in the desert habitat, and Apodemus peninsulae primarily in the shrub habitat. The shrub habitat hosted the largest number of small mammal species among the three types of habitats, supporting the productivity hypothesis. Habitat separation is an important mechanism for structuring small mammal communities in Inner Mongolia grasslands.

环境温度和繁殖经历对黑线仓鼠哺乳期能量收支的影响

环境温度和繁殖经历对黑线仓鼠哺乳期能量收支的影响

不同干扰下阿拉善荒漠啮齿动物优势种对气候变化的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 不同干扰下阿拉善荒漠啮齿动物优势种对气候变化的响应 DOI: 10.5846/stxb201408061564 作者: 作者单位: 内蒙古农业大学生态环境学院,内蒙古农业大学生态环境学院,内蒙古自治区林业监测规划院,内蒙古农业大学生态环境学院,中国农业科学研究院草原研究所,内蒙古医科大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(30160019, 30560028, 30760044, 31160096);公益性行业(农业)科研专项经费项目(201203041);中央级公益性科研院所基本科研业务费专项资金(中国农业科学院草原研究所)资助项目(1610332015012) Responses of dominant rodentspecies to climate change in different disturbed habitats in the Alashan desert Author: Affiliation: College of Ecology and Environmental Science, Inner Mongolia Agricultural University,,College of Ecology and Environmental Science, Inner Mongolia Agricultural University,,,College of Ecology and Environmental Science, Inner Mongolia Agricultural University,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:气候变化已对物种分布范围和丰富度产生了极大的影响。荒漠生态系统对气候变化的反应可能更加敏感。作为荒漠生态系统的重要组成者,了解荒漠啮齿动物特别是优势鼠种将对气候变化如何响应,对于荒漠地区生物多样性的维持将具有重要意义。2002-2010年,采用标志重捕法对阿拉善荒漠4种不同生境下啮齿动物优势种群进行了研究,分别利用Spearman相关分析以及典范对应分析(Canonical Correspondence analysis,CCA)对啮齿动物优势种群动态与年平均温度和年降水量的相关性进行了分析。结果表明,不同啮齿动物优势种对温度和降雨的响应不同,尤其以子午沙鼠表现最为显著。跳鼠对温度的适宜性要高于仓鼠科的子午沙鼠和黑线仓鼠,而仓鼠科啮齿动物对降雨的适宜性高于跳鼠。较小尺度上的人为干扰更可能从改变食性和生境的途径上加剧或缓冲降雨对荒漠啮齿动物优势种的影响,而不是改变温度对啮齿动物的作用。 Abstract:The Northern Hemisphere of the earth has been experiencing remarkable climate warming in last century. Climate change has a profound influence on the distribution, range, and richness of species. Temperature and precipitation are two indicators of climate in most of studies. Because hydrothermic factor has a significant effect on desert ecosystem, it is particularly sensitive to climate fluctuations. Rodents are especially important components of the desert ecosystem, and are dominant species that play a key role in these systems. In addition, desert rodents have played an important role in the development of ecological theory and in the understanding of adaptations to xeric environments. Therefore, understanding the response of dominant rodent species to climate change is significant to biodiversity conversion. Desert ecosystems in China, compared with similar ecosystems in other continents, suffer more disturbances from human activities. Alxa desert is a typical desert ecosystem in China. Annual mean temperatures of Alxa desert have risen 9.05 degrees, and precipitation has increased 23.46mm in last decade. Against this Background, the response of desert rodents, especially dominant rodent species, to climate change, and how this response influences by human disturbances are keeping unknown. A study was conducted from 2002 to 2010 at prohibited-grazing, rotational-grazing, over-grazing, and cultivated sites to investigate the response of dominant rodent species to climate change in Alashan, Inner Mongolia, China. Rodent species were identified among and monitored with a live-trapping method. We trapped nine species including Dipus sagitta, Stylodipus andrewsi, Allactaga sibirica, Phodopus roborovskii, Cricetulus barabensis, Allocricetulus eversmanni, Meriones meridianus, Meriones unguiculatus and Spermophilus alaschanicus. M. meridianus was the dominant rodent species in prohibited-grazing and cultivated sites. However, A. sibirica and D. sagitta was the dominant rodent species in over-grazing and rotational grazing sites, respectively. The relationships of annual mean temperature and precipitation with rodent abundance were analyzed with Spearman correlation analysis and canonical correspondence analysis. The results showed that the response to temperature and precipitation was variable across rodent species. M. meridianus abundance was significantly correlated with annual precipitation in the previous year and annual mean temperature. The abundance optimum of A. sibirica and D. sagitta with respect to temperature was higher than that of M. meridianus and C. barabensis, but this pattern was reversed with respect to precipitation. Effect of temperature on desert rodent should be worked through influencing biology and ecological characteristics of animal, while precipitation affects the rodents through changing food resource and habitat. Precipitation has a pulse effect on M. meridianus abundance. These results suggested that human disturbance, occurring at a smaller spatial scale, should intensify or buffer the influence of precipitation rather than temperature on the dominant rodent species through altering food resource availability and habitat quality. These disturbances complex the response of rodent species to climate change, and have a further effect to community structure of desert rodent. 参考文献 相似文献 引证文献

Plasticity in gastrointestinal morphology and enzyme activity in lactating striped hamsters (Cricetulus barabensis).

In small mammals, marked phenotypic plasticity of digestive physiology has been shown to make it easier for them to cope with energetically stressful periods, such as lactation. It has been proposed that the capacity of the gut to digest and absorb food is not the limiting factor to sustained energy intake (SusEI) during peak lactation. In this study, plasticity in energy intake and gastrointestinal morphology was examined in striped hamsters at different stages of reproduction and when raising litters of different sizes. Mechanisms associated with digestive enzymes and neuroendocrine hormones underpinning the plasticity were also examined. Females significantly increased energy intake, digestibility, digestive tract mass and the activity of stomach pepsin and small intestine maltase, sucrase and aminopeptidase in peak lactation compared with the non-productive and post-lactating periods. Further, females raising large litters significantly increased energy intake, digestibility, gastrointestinal mass and activity of digestive enzymes, and weaned heavier offspring compared with those nursing small and medium litters, indicating that the significant plasticity of digestive physiology increased reproductive performance. Agouti-related protein (AgRP) mRNA expression in the hypothalamus was up-regulated significantly in females raising large litters relative to those raising small litters. Serum leptin levels, and mRNA expression of hypothalamus neuropeptide Y (NPY) and the anorexigenic neuropeptides pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) did not differ among females raising small, medium and large litters. Leptin levels in lactation may only reflect a state of energy balance rather than being the prime driver of hyperphagia. Some hypothalamic neuropeptides, such as NPY, POMC and CART, may be involved in the limits to the SusEI during lactation.

Effect of temperature on oxidative stress, antioxidant levels and uncoupling protein expression in striped hamsters

According to the rate of living-free radical hypothesis, higher metabolic rates should increase reactive oxygen species (ROS) production. However, the “uncoupling to survive” hypothesis postulates that uncoupling proteins (UCPs) can decrease ROS production by lowering the potential of the inner mitochondrial membrane, in which case the correlation between metabolic rate and ROS levels would be a negative rather than positive. In this study, we examined energy intake, oxidative stress levels, antioxidant activity and the expression of UCPs in brown adipose tissue (BAT), and in the liver, heart, skeletal muscle and brain, of striped hamsters (Cricetulus barabensis) acclimated to either 5°C or 32.5°C. The energy intake of hamsters acclimated to 5°C increased by 70.7%, whereas the energy intake of hamsters acclimated to 32.5°C decreased by 31.3%, relative to hamsters kept at room temperature (21°C) (P<0.05). Malonadialdehyde (MDA) levels, total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-PX) activity in BAT significantly decreased in 5°C group, but increased in 32.5°C group, relative to the 21°C group. Neither ROS levels (i.e. H2O2 levels), nor antioxidants in skeletal muscle, liver, heart or brain tissue, were affected by temperature. UCP1 expression in BAT was significantly up-regulated in 5°C group, but down-regulated in 32.5°C group, relative to the 21°C group. UCP3 expression of skeletal muscle was also up-regulated significantly in hamsters acclimated to 5°C. These results suggest that the relationship between ROS levels and metabolic rate was negative, rather than positive. UCP1 expression in BAT may have played a role in lowering ROS levels.

Description and phylogenetic affinities of two new species of Nomadolepis (Eucestoda, Hymenolepididae) from Eastern Palearctic

Two new species of hymenolepidid cestodes belonging to the genus Nomadolepis are described from small mammals in western Siberia and the Far East, Russian Federation. Nomadolepis fareasta n. sp. is described from the striped dwarf hamster Cricetulus barabensis in Amurskaya Oblast' and Nomadolepis shiloi n. sp. is described from the Eurasian harvest mouse Micromys minutus from Novosibirskaya Oblast' and Amurskaya Oblast'. Nomadolepis fareasta n. sp. differs from Nomadolepis merionis, Nomadolepis ellobii and N. shiloi n. sp. in having a substantially longer strobila, longer cirrus-sac and wider ovary. Furthermore, N. fareasta n. sp. can be readily distinguished from its congeners by the arrangement of the testes and the number and size of rostellar hooks. Nomadolepis shiloi n. sp. differs from N. merionis, N. ellobii and N. fareasta n. sp. by the number and length of the rostellar hooks, the presence of irregular transverse anastomoses as well as the length of the cirrus-sac and position of the cirrus-sac in relation to the poral ventral osmoregulatory canal. Morphological differentiation of the two new species from morphologically similar Palearctic species of the related genus Rodentolepis (sensu lato) from rodents is also provided. Phylogenetic affinities of Nomadolepis were studied for the first time using partial sequences of the nuclear ribosomal 28S DNA gene. Phylogenetic analysis strongly supported the status of Nomadolepis as a separate genus closest to Pararodentolepis.

Correlations between phytohemagglutinin response and leukocyte profile, and bactericidal capacity in a wild rodent.

Phytohemagglutinin (PHA)-induced swelling is widely used to investigate cell-mediated and innate immunity across different vertebrate taxa. However, its physiological mechanism is still an open question due to the complexity of the involved immune components. In the present study, we measured the synchronous variations of PHA response, the proportion of different subtypes of leukocytes, as well as serum bactericidal capacity in circulation blood at 6, 12 and 24 h after PHA versus PBS injection in striped hamster, Cricetulus barabensis. First, the results showed that PHA responses reached a peak at 6 h postinjection, then sharply declined at 12 h and 24 h postinjection. Serum bactericidal capacity was higher at 6 h and 12 h than at 24 h. The proportion of different subtypes of leukocytes, as well as the ratio of neutrophils to lymphocytes did not display significant changes across different time points. Second, PHA response was positively correlated with the proportion of neutrophils and serum bactericidal capacity. The proportion of monocytes was negatively correlated with that of eosinophils and neutrophils. The proportion of basophils was negatively correlated with that of lymphocytes. Our results indicate that earlier enhanced PHA response is important for the striped hamster to cope with changing environmental conditions due to its small body mass, and the increased components of innate immunity in circulation blood may contribute to the enhancement of PHA swelling response.

食物限制对黑线仓鼠免疫功能的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 食物限制对黑线仓鼠免疫功能的影响 DOI: 10.5846/stxb201305241171 作者: 作者单位: 曲阜师范大学生命科学学院,曲阜师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(31070332,31370427);山东省自然科学基金(ZR2013CM019);曲阜师范大学博士启动基金(bsqd20100204) Effect of food restriction on immune function in the striped hamster (Cricetulus barabensis) Author: Affiliation: College of Life Sciences,Qufu Normal University,Qufu,273165,Shandong Province Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:温带地区小型哺乳动物经常面临着食物资源的波动。食物对动物的免疫功能具有重要影响。将19只成年雄性黑线仓鼠(Cricetulus barabensis)随机分为自由取食组(n=9)和限食组(n=10)。注射植物血球凝集素(PHA)来测定细胞介导的免疫反应,用匙孔血蓝蛋白(KLH)免疫动物,然后测定抗KLH抗体的浓度以反映其体液免疫功能。旨在检验食物限制是否会抑制黑线仓鼠的细胞免疫和体液免疫功能。结果发现,与对照组相比,限食组黑线仓鼠具有较低的体重、体脂、脾脏鲜重、血清瘦素水平、免疫球蛋白IgG和IgM浓度。而限食对胸腺鲜重、白细胞数、皮质酮水平以及PHA反应没有显著影响。结果表明黑线仓鼠免疫系统的不同成分对限食反应存在差异,在食物资源短缺时,黑线仓鼠防御细胞外病原体的能力降低,从而导致生存能力的下降。 Abstract:The immune system protects animals against environmental pathogens, and hence it plays an important role in their survival and fitness. However, immune function is influenced by many factors including food availability. Small mammals in the temperate zone often face fluctuations in food availability, which is important to their survival. Changes in food availability may have a great influence on an animals' immunity. Some investigators have examined the effect of reduced food availability (i.e., food restriction) on the immune function in small rodents, but their results are often inconsistent. Food restriction could depress, enhance or have no effect on immunity in different species. In order to clarify the discrepancy between results, the striped hamster (Cricetulus barabensis) was used to examine the effect of food restriction on its immune function. The striped hamster is a major pest rodent in northern China. It is granivorous, nocturnal and feeds mainly on plant stems and leaves during summer and forages crop seeds in winter. The climate is arid and characterized by warm and dry summers and cold winters. Thus, the species experiences great seasonal fluctuations in temperature, photoperiod as well as food quality and availability. The question we focused on in the present study was how the immune function would vary in the face of reduced food availability for hamsters. Nineteen adult male hamsters were randomly divided into the fed ad libitum group (Fed, n=9) and food restricted group (FR, n=10) (90% of baseline food intake). The course of food restriction was 21 days. Hamsters were injected with phytohaemagglutinin (PHA) and keyhole limpet haemocyanin (KLH) solution to assess cellular and humoral immunity, respectively. Our goal was to test whether food restriction would suppress cellular and humoral immunity in striped hamsters. Body mass in the FR group decreased significantly after 21 days of food restriction, whereas body mass in the Fed group did not change significantly. Body mass in the FR group was significantly lower than that of the Fed group after 10 days of food restriction. Food restriction significantly reduced perirenal fat, perirenal fat content, retroperitoneal fat, total body fat, and wet spleen mass in the FR group compared with the Fed group. However, it had no significant effect on the wet thymus mass or white blood cells. Immunoglobulin (Ig) G and IgM concentrations were reduced significantly in the food restricted hamsters in contrast with the Fed control group, which indicated the suppressive role of food restriction on humoral immunity. PHA response did not differ between the two groups, suggesting cellular immunity was not influenced by food restriction. Food restricted hamsters had significantly lower serum leptin levels than that of the control group, while corticosterone levels were not affected by food restriction. Taken together, our results suggest that different components of the immune system respond differently to food restriction in striped hamsters. Humoral immunity was suppressed in food restricted hamsters, which might be due to their lower body fat mass and lower leptin levels. In the face of food shortage, striped hamsters might be more prone to extracellular pathogens and their survival capability would decrease. 参考文献 相似文献 引证文献

EP-1不育剂对内蒙古沙地黑线仓鼠种群结构与繁殖的作用

PDF HTML阅读 XML下载 导出引用 引用提醒 EP-1不育剂对内蒙古沙地黑线仓鼠种群结构与繁殖的影响 DOI: 10.5846/stxb201308132066 作者: 作者单位: 中国科学院亚热带农业生态研究所,中国科学院亚热带农业生态研究所,四川大学生命学院,中国科学院亚热带农业生态研究所,内蒙古锡林郭勒盟林业局,内蒙古锡林郭勒盟林业局,内蒙古锡林郭勒盟林业局,内蒙古锡林郭勒盟林业局 作者简介: 通讯作者: 中图分类号: 基金项目: 公益性行业(农业)科研专项经费项目(201203041) Effect of a contraceptive compound (EP-1) on the population reproduction on the striped hamster(Cricetulus barabensis) in Inner Mongolia Author: Affiliation: institute of subtropical agriculture , the chinese academy of science,institute of subtropical agriculture , the chinese academy of science,,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:2003年在内蒙古锡林郭勒盟浑善达克沙地进行了EP-1不育剂控制黑线仓鼠的野外实验,分析新型EP系列不育剂对黑线仓鼠种群结构和繁殖的影响。采用逐月夹线调查方法,监测EP-1不育剂对沙地黑线仓鼠种群结构与数量动态的作用。结果表明,投药区与对照区相比,不育剂对黑线仓鼠的性别比例没有影响,对照区域投药区相比雄性比例没有差异。投药区黑线仓鼠种群幼鼠比例下降,比对照区相比幼鼠比例下降40%-60%,持续时间达4个月以上。春季一次性投放EP-1不育剂,可实现对沙地黑线仓鼠整个繁殖季节的繁殖控制。此外,EP-1不育剂对沙地鼠类种群年龄结构与数量的作用成效,随着时间的推移逐渐下降,这可能跟沙地鼠类具有扩散迁移习性有关。 Abstract:Hunshandake Sandland is one of the biggest areas of semi-desert in China. It is also the primary source of sandstorms affecting Beijing and Tianjin. In recent years, scientists and the Chinese government have paid increased attention to the ecological restoration and reconstruction of the Hunshandake Sandland. To restore the vegetation of this region, the primary problem is how to control the populations of rodents.The striped hamster (Cricetulus barabensis) is a widely distributed species in the grasslands of Inner Mongolia. Striped hamsters like to eat plant seeds, which account for 70% of all their food. As a result, this animal has a negative impact on the restoration of vegetation on sandy land. It is necessary to find an effective way to control their population. Traditional chemical rat poisons can kill most individuals of a population in short time. However, thanks to their high reproductive ability, rodent populations are able to recover rapidly. Moreover, traditional chemical rat poisons pollute the environment and hurt nontarget animals at the same time.EP-1 is a new type of contraceptive compound, the main ingredients of which are levonorgestrel and quinestrol. EP-1 does not kill its target animals; instead, it affects the female reproductive system but the animals are able to recover from the damage. Laboratory experiments have shown that EP-1 has a remarkable impact on controlling the reproduction of rodents. Moreover, EP-1 has little effect on nontarget animals. Environmental pollution from EP-1 is also less than that from traditional chemical rat poisons.To test the effect of EP-1 on reproduction in the striped hamster, EP-1 baits were placed in the Hunshandake Sandland in April 2003. We chose four plots: two were baited and the others were control areas. Monthly trapping censuses were conducted to monitor the reproductive parameters of the rodent population during June to October. EP-1 did not influence the sex ratio of the striped hamster, and no significant differences were observed in the proportions of male hamsters between the baited and control areas (Student's t test, P < 0.05). EP-1 baiting obviously influenced the age structure of the striped hamster population, as the proportion of juvenile animals found in the baited area was only 40%-50% of that in the control area (Student's t test, P < 0.05). This impact lasted for more than 4 months. EP-1 baiting obviously influenced reproductive parameters. In the baited areas, EP-1 caused damage to the uteri of 70%-80% adult female hamsters, and in June 100% of the uteri were damaged. The organs turned black and uterine cysts were evident. This impact lasted for more than 5 months. Moreover, EP-1 baiting significantly reduced female fertility as no pregnant females were found in baited areas in June. The pregnancy rates in the baited areas were also very low in July and August: significantly different from the control area (Student's t test, P < 0.055). Litter sizes in the baited area were also influenced by EP-1 and were significantly lower than in the control area (pooled Student's t tests, P < 0.05). The impact of EP-1 on these rodents lasted for more than 4 months after a single baiting in spring, suggesting that it can influence the whole breeding season of this species. This fertility control effect might be related to the foraging behavior of striped hamsters. The impact of EP-1 baiting on the hamster populations declined with time, suggesting that female hamsters might be able to recover from the damage caused by EP-1. This recovery might also be explained by dispersal of the hamsters. 参考文献 相似文献 引证文献

Genetic variation of the striped hamster (Cricetulus barabensis) and the impact of population density and environmental factors

The striped hamster (Cricetulus barabensis) is a dominant rodent species in the North China Plain and has suffered a continuous decline of population size in the last 17 years. However, little is known about the population genetic structure of this species and how it is influenced by geographical and environmental factors. In the present study, we investigated the genetic diversity and genetic differentiation of the striped hamsters in four geographical populations of different environmental features. The genetic variability for a sample of 158 animals from the four populations was estimated using data from 10 microsatellite loci. Genetic diversity exists in the striped hamster. The number of alleles and the proportion of heterozygosity indicate moderate variability. A total of 46 alleles were detected, with a moderate mean number of alleles. Significant genetic differentiation (p < 0.01) exists among all four examined geographical populations. Population-specific alleles and variable allelic richness were detected in all populations regardless of the geographical distances. The genetic diversity positively correlates with the population density, while the genetic distance is partially affected by the geographical distances. Moreover, the habitat environment is also an important factor influencing the genetic differentiation of the species. The genetic diversity of the striped hamster is mainly impacted by population density, while partially influenced by geographical distances. The results of our study and other studies collectively suggest that a minimum geographical distance is required to prevent gene flow between different populations and for genetic differentiation to be pronounced.

Effect of RFRP-3 on reproduction is sex- and developmental status-dependent in the striped hamster (Cricetulus barabensis)

RFamide-related peptides (RFRPs) are orthologous to gonadotropin-inhibitory hormone (GnIH) inhibiting gonadotropin release. There are only two RFRP sequences (RFRP-1 and RFRP-3) encoded in rodents. RFRP-3, which was considered as a hypothetical inhibitor on GnRH, shows a stimulatory effect on the male Syrian and male Siberian hamster in short days. As a dominant rodent pest in northern China farmland, the striped hamster (Cricetulus barabensis) has higher reproductive activities and could act as a model to study the mechanism of reproduction. However, the effect of RFRP-3 on the reproductive activity for the striped hamster is less understood. In the study, we cloned 643 bp RFRP cDNA from the striped hamster hypothalamus, which contained an ORF of 570 bp encoding two RFamide-related peptide (RFRP) sequences: SPAPANKVPHSAANLPLRF-NH2 (C. barabensis RFRP-1) and TLSRVPSLPQRF-NH2 (C. barabensis RFRP-3). We also investigated the expression variation of RFRP mRNA and GnRH mRNA in the hypothalamus from hamsters with different developmental statuses (7-week-, 13-week- and 1.5-year-olds) using FQ-PCR, in which the 13-week-old female individuals were in estrous. The striped hamsters that are 7 weeks and 1.5 years old are non-breeding individuals, and those that are 13-week hamsters have breeding phenomena. The highest hypothalamus RFRP mRNA level was found in breeding males as compared to non-breeding males. Conversely, the lowest RFRP mRNA level in the hypothalamus was observed in breeding females, with no significant level when the breeding females were compared to the 7-week-old individuals. Additionally, the investigation of GnRH expression level showed a declining expression trend across the developmental stages (7-week-, 13-week- and 1.5-year-olds) in both sexes. Significant negative and positive relationships were detected in the 13-week estrous female (r=-0.997, P=0.035) and the 13-week male (r=0.998, P=0.029) striped hamsters respectively, which suggest that RFRP-3 has inhibitory and stimulatory effects on female and male adults respectively. Our results suggest that the effects of RFRP-3 on reproduction are sex- and developmental status-dependent in the striped hamster.

Temporal change in body mass of two sympatric hamster species and implications for population dynamics

Shifting of body size distributions of animals has been a long-time focus in population ecology, but the underlying mechanism of density-dependent changes in body size and its implications for population dynamics of animals are largely unknown. In this 26-year study, we investigated intrinsic and extrinsic factors affecting body mass of the Chinese striped hamster (Cricetulus barabensis Pallas, 1773) and the greater long-tailed hamster (Tscherskia triton de Winton, 1899) in the Northern China Plain. We proposed three hypotheses to explain body mass shifts in the two hamster species: growth, survival, and reproduction hypotheses. Our results showed that mean and maximum body masses of both hamster species were positively correlated with population density, and that this density-dependent change in body mass is more likely to be caused by a change in mortality rates, not by a change in growth rates or reproduction rates. The sustained decline of body mass during the study period was probably caused by increased mortality owing to an increase in the area of agricultural irrigation. Our results suggest that, under the condition of lacking survival and growth data, the maximum body mass (which represents survival rate), minimum body mass (which represents growth rate), and mean body mass are very useful criteria in revealing intrinsic and extrinsic effects on population dynamics and the underlying mechanisms.

Sporadic disorders in the meiotic prophase I inCricetulus barabensishybrids (Cricetidae, Rodentia) do not lead to reproductive isolation between karyomorphs

Electron microscopy analysis of the synaptonemal complex was carried out for the first time in Cricetulus barabensis pseudogriseus, fertile F1 hybrids of C. b. pseudogriseus × C. b. griseus, C. b. griseus × C. b. barabensis, and back-cross hybrids C. b. pseudogriseus × (F1 C. b. pseudogriseus × C. b. griseus). Meiotic disturbances were identified in the nuclei of single hybrid spermatocytes, including atypical synapsis, associations of autosomes with a sex bivalent, and sex body formation errors. Our study confirms the results of the molecular genetic and craniometric analysis of these forms. Despite the geographical segregation, three chromosomal forms of Cricetulus barabensis complex do not establish reliable cytogenetic barriers.