Background: Sexual size dimorphism(SSD) occurs in a wide range of species in birds and other animals, but the magnitude of SSD often varies with environmental conditions. In general, in the developmental stages, the l...Background: Sexual size dimorphism(SSD) occurs in a wide range of species in birds and other animals, but the magnitude of SSD often varies with environmental conditions. In general, in the developmental stages, the larger sex is more vulnerable to adverse environmental conditions because the larger sex requires more energy than the smaller sex. However, this may not hold true for birds with large brood sizes; the larger sex can acquire more food by suppressing the smaller sex. In addition, most previous studies have been experimental, such as by manipulating clutch size and ectoparasites, which may not reflect natural conditions.Methods: In the present study, we propose a general framework to assess sexual differences in environmental sensitivity in natural populations. Because environmental conditions change throughout the breeding season, seasonal changes of nestling SSD and sex ratio should reflect sexual differences in environmental sensitivity. We applied this approach to a large dataset(1555 nestlings over 5 years) of Japanese Tits(Parus minor). In this population, the male nestling is generally larger than the female(5% SSD in body weight).Results: We found that the magnitude of SSD(weight, tarsus, wing) and fledgling sex ratio increased both in the beginning and the end of the breeding season.Conclusion: Our study suggested that female nestlings are more valuable to poor environmental conditions in the relatively fecund species. This study underscores the importance of brood size on sexual differences in environmental stochasticity and our framework encourages comparative analysis among different bird species.展开更多
Among more than 75 variants of microcystin （MC）, microcystin-LR （MC-LR） is one of the most common toxins. In this study, the feasibility of using Caenorhabditis elegans to evaluate MC-LR toxicity was studied. C. e...Among more than 75 variants of microcystin （MC）, microcystin-LR （MC-LR） is one of the most common toxins. In this study, the feasibility of using Caenorhabditis elegans to evaluate MC-LR toxicity was studied. C. elegans was treated with MC-LR at different concentrations ranging from 0.1 to 80 μg/L. The results showed that MC-LR could reduce lifespan, delay development, lengthen generation time, decrease brood size, suppress locomotion behavior, and decreases hsp-16-2-gfp expression. The endpoints of generation time, brood size, and percentage of the population expressing hsp-16-2-gfp were very sensitive to 1.0μg/L of MC-LR, and would be more useful for the evaluation of MC-LR toxicity. Furthermore, the tissue-specific hsp-16-2-gfp expressions were investigated in MC-LR-exposed animals, and the nervous system and intestine were primarily affected by MC-LR. Therefore, the generation time, brood size, and hsp-16-2-gfp expression in C. elegans can be explored to serve as valuable endpoints for evaluating the potential toxicity from MC-LR exposure.展开更多
Background: Life history traits play critical roles in population survival and evolution.Breeding information should be particularly detailed in order to provide significant insights into the population status and the...Background: Life history traits play critical roles in population survival and evolution.Breeding information should be particularly detailed in order to provide significant insights into the population status and the evolution of other traits.To our knowledge, there is still no information about the breeding biology of Spectacled Parrotbill(Sinosuthora conspicillatus), an endemic parrotbill in China.Methods: We searched the nests, checked all nests found and recorded the information of eggs, nestlings and nest sites of the Spectacled Parrotbill from 2013 to 2015 at Lianhuashan National Nature Reserve in Gansu Province, China.Results: A total of 16 nests were found.Nest trees were artificial young spruces and honeysuckles.Mean nest height was 0.89 ± 0.47 m(n = 16) above the ground level.All nests were cup-shaped and constructed using leaves, fine strips of barks and grasses by both parents.The mean clutch size was 4.42 ± 0.79(n = 12).The eggs were oval in pale blue without speckles, and the mean egg mass was 1.25 ± 0.07 g(n = 27).The egg length was 15.56 ± 0.46 mm(n = 27) and the width was 12.46 ± 0.29 mm(n = 27).Incubation period was 13 days and nestling period was 13–14 days.The breeding success rate was 46%, and among those failed nest, 71% were depredated and 29% were deserted.Conclusion: Detailed life history information about parrotbill is still limited.The breeding biology of Spectacled Parrotbill reported in the present study should be helpful for further research about population, breeding behavior and conservation of this bird.展开更多
DEHP(di(2-ethylhexyl) phthalate) is an endocrine disruptor commonly found in plastic products that has been associated with reproduction alterations, but the effect of DEHP on toxicity is still widely unknown. Using D...DEHP(di(2-ethylhexyl) phthalate) is an endocrine disruptor commonly found in plastic products that has been associated with reproduction alterations, but the effect of DEHP on toxicity is still widely unknown. Using DEHP concentrations of 10, 1, and 0.1 mg/L, we showed that DEHP reduced the reproductive capacity of Caenorhabditis elegans after 72 hr. of exposure. DEHP exposure reduced the reproductive capacity in terms of decreased brood sizes, egg hatchability(0.1, 1 and 10 mg/L), and egg-laying rate(1 and 10 mg/L), and increased numbers of fertilized eggs in the uterus(1 and 10 mg/L). DEHP also caused damage to gonad development. DEHP decreased the total number of germline cells, and decreased the relative area of the gonad arm of all exposure groups, with worms in the 1 mg/L DEHP exposure group having the minimum gonad arm area. Additionally, DEHP caused a significant concentration-dependent increase in the expression of unc-86. Autophagy and ROS contributed to the enhancement of DEHP toxicity in reducing reproductive capacity, and glutathione peroxidase and superoxide dismutase were activated as the antioxidant defense in this study. Hence, we found that DEHP has a dual effect on nematodes. Higher concentration(10 mg/L) DEHP can inhibit the expression of autophagy genes( atg-18, atg-7, bec-1, lgg-1 and unc-51), and lower concentrations(0.1 and 1 mg/L) can promote the expression of autophagy genes. Our data highlight the potential environmental risk of DEHP in inducing reproductive toxicity toward the gonad development and reproductive capacity of environmental organisms.展开更多
文摘Background: Sexual size dimorphism(SSD) occurs in a wide range of species in birds and other animals, but the magnitude of SSD often varies with environmental conditions. In general, in the developmental stages, the larger sex is more vulnerable to adverse environmental conditions because the larger sex requires more energy than the smaller sex. However, this may not hold true for birds with large brood sizes; the larger sex can acquire more food by suppressing the smaller sex. In addition, most previous studies have been experimental, such as by manipulating clutch size and ectoparasites, which may not reflect natural conditions.Methods: In the present study, we propose a general framework to assess sexual differences in environmental sensitivity in natural populations. Because environmental conditions change throughout the breeding season, seasonal changes of nestling SSD and sex ratio should reflect sexual differences in environmental sensitivity. We applied this approach to a large dataset(1555 nestlings over 5 years) of Japanese Tits(Parus minor). In this population, the male nestling is generally larger than the female(5% SSD in body weight).Results: We found that the magnitude of SSD(weight, tarsus, wing) and fledgling sex ratio increased both in the beginning and the end of the breeding season.Conclusion: Our study suggested that female nestlings are more valuable to poor environmental conditions in the relatively fecund species. This study underscores the importance of brood size on sexual differences in environmental stochasticity and our framework encourages comparative analysis among different bird species.
基金supported by the National Natural Sci-ence Foundation of China (No. 30771113, 30870810)the Doctoral Program of Higher Education of China (No.20050286035)+1 种基金the Jiangsu 333 Project Foundation (No.07056)the Natural Science Foundation of Jiangsu Province (No. BK2006107, BK2008320)
文摘Among more than 75 variants of microcystin （MC）, microcystin-LR （MC-LR） is one of the most common toxins. In this study, the feasibility of using Caenorhabditis elegans to evaluate MC-LR toxicity was studied. C. elegans was treated with MC-LR at different concentrations ranging from 0.1 to 80 μg/L. The results showed that MC-LR could reduce lifespan, delay development, lengthen generation time, decrease brood size, suppress locomotion behavior, and decreases hsp-16-2-gfp expression. The endpoints of generation time, brood size, and percentage of the population expressing hsp-16-2-gfp were very sensitive to 1.0μg/L of MC-LR, and would be more useful for the evaluation of MC-LR toxicity. Furthermore, the tissue-specific hsp-16-2-gfp expressions were investigated in MC-LR-exposed animals, and the nervous system and intestine were primarily affected by MC-LR. Therefore, the generation time, brood size, and hsp-16-2-gfp expression in C. elegans can be explored to serve as valuable endpoints for evaluating the potential toxicity from MC-LR exposure.
基金supported by the National Natural Science Foundation of China(31472012,31270468)
文摘Background: Life history traits play critical roles in population survival and evolution.Breeding information should be particularly detailed in order to provide significant insights into the population status and the evolution of other traits.To our knowledge, there is still no information about the breeding biology of Spectacled Parrotbill(Sinosuthora conspicillatus), an endemic parrotbill in China.Methods: We searched the nests, checked all nests found and recorded the information of eggs, nestlings and nest sites of the Spectacled Parrotbill from 2013 to 2015 at Lianhuashan National Nature Reserve in Gansu Province, China.Results: A total of 16 nests were found.Nest trees were artificial young spruces and honeysuckles.Mean nest height was 0.89 ± 0.47 m(n = 16) above the ground level.All nests were cup-shaped and constructed using leaves, fine strips of barks and grasses by both parents.The mean clutch size was 4.42 ± 0.79(n = 12).The eggs were oval in pale blue without speckles, and the mean egg mass was 1.25 ± 0.07 g(n = 27).The egg length was 15.56 ± 0.46 mm(n = 27) and the width was 12.46 ± 0.29 mm(n = 27).Incubation period was 13 days and nestling period was 13–14 days.The breeding success rate was 46%, and among those failed nest, 71% were depredated and 29% were deserted.Conclusion: Detailed life history information about parrotbill is still limited.The breeding biology of Spectacled Parrotbill reported in the present study should be helpful for further research about population, breeding behavior and conservation of this bird.
基金supported by the Fundamental Research Fund of Central Public Welfare Research Institutions in 2019(Innovation team project of new approach and application on substitution toxicology of environmental hormone substances).
文摘DEHP(di(2-ethylhexyl) phthalate) is an endocrine disruptor commonly found in plastic products that has been associated with reproduction alterations, but the effect of DEHP on toxicity is still widely unknown. Using DEHP concentrations of 10, 1, and 0.1 mg/L, we showed that DEHP reduced the reproductive capacity of Caenorhabditis elegans after 72 hr. of exposure. DEHP exposure reduced the reproductive capacity in terms of decreased brood sizes, egg hatchability(0.1, 1 and 10 mg/L), and egg-laying rate(1 and 10 mg/L), and increased numbers of fertilized eggs in the uterus(1 and 10 mg/L). DEHP also caused damage to gonad development. DEHP decreased the total number of germline cells, and decreased the relative area of the gonad arm of all exposure groups, with worms in the 1 mg/L DEHP exposure group having the minimum gonad arm area. Additionally, DEHP caused a significant concentration-dependent increase in the expression of unc-86. Autophagy and ROS contributed to the enhancement of DEHP toxicity in reducing reproductive capacity, and glutathione peroxidase and superoxide dismutase were activated as the antioxidant defense in this study. Hence, we found that DEHP has a dual effect on nematodes. Higher concentration(10 mg/L) DEHP can inhibit the expression of autophagy genes( atg-18, atg-7, bec-1, lgg-1 and unc-51), and lower concentrations(0.1 and 1 mg/L) can promote the expression of autophagy genes. Our data highlight the potential environmental risk of DEHP in inducing reproductive toxicity toward the gonad development and reproductive capacity of environmental organisms.
