首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
不同强度冷应激下仔猪淋巴细胞HSP70 mRNA的转录规律   总被引:3,自引:0,他引:3  
采用实时荧光定量PCR技术检测仔猪血液淋巴细胞HSP70 mRNA的转录量,探讨不同冷应激强度对淋巴细胞HSP70 mRNA转录量的影响.结果表明,仔猪在-10~-4℃冷暴露0.5h,淋巴细胞HSP70 mRNA的转录量迅速升高(P<0.05),并一直保持高水平至6h(P<0.05),随后下降,冷暴露结束后24h恢复正常.在4~10℃冷暴露前后,淋巴细胞HSP70 mRNA转录量无明显变化(P>0.05).结果提示,冷暴露温度越低,淋巴细胞中HSP70 mRNA转录越迅速,但冷暴露结束进入常温后HSP70 mRNA转录水平再次升高的时间延后;HSP70 mRNA转录呈现规律性变化,可以考虑把HSP70 mRNA优先作为评估不同冷应激的客观指标.表1图1参14  相似文献   

2.
冷应激对断乳仔猪ACTH及皮质醇的影响   总被引:1,自引:2,他引:1  
断乳仔猪在-3~3℃低温条件下冷暴露24h,然后在15~18℃室温条件下恢复,检测血浆促肾上腺皮质激素(ACTH)和皮质醇的动态变化.结果表明,仔猪血浆中ACTH和皮质醇含量随冷暴露时间延长而逐渐升高,冷应激6h时,ACTH含量高于冷应激前的水平(P<0.05);冷应激12h时,ACTH和皮质醇含量与冷应激前比较均有极显著升高(P<0.01);冷应激24h时,两激素含量与冷应激前无显著差异.终止冷暴露后0.5h,ACTH和皮质醇含量均高于冷应激前水平(P<0.05,P<0.01);3h时两激素水平基本恢复正常,但6h时两激素水平再次升高(P<0.01),呈波动性变化.表1参10  相似文献   

3.
采用Western blot和实时荧光定量RT-PCR方法,研究不同强度不同时间冷刺激后大鼠心脏、大脑、睾丸和肺脏中冷诱导RNA结合蛋白(CIRP)的表达情况.结果表明:常温(20℃±1℃)下大鼠4种组织中均存在一定的CIRP的表达;急性冷刺激组(-10℃±1℃、-4℃±1℃、0℃±1℃、4℃±1℃)心脏、大脑和睾丸中CIRP mRNA表达在冷刺激0~6 h呈上升趋势,6 h时达到最高值,随后呈下降趋势,肺脏中CIRP mRNA表达在0~6 h呈下降趋势,在6 h时达到最低值,随后呈上升趋势;慢性冷应激组(10℃±1℃)大鼠心脏、大脑和睾丸3种组织中CIRP mRNA在不同时间点(1周、2周、3 W周)的表达均高于正常对照组(P>0.05),肺脏CIRP mRNA表达均低于对照组(P>0.05),并且同一组织不同时间点之间差异不显著(P>0.05).可见冷刺激后CIRP的表达存在一定规律并且表现出组织特异性,可能与组织保护特异性有关.  相似文献   

4.
在捕食压力下,大鼠脾脏诱导型一氧化氮合酶(iNOS)明显表达,说明iNOS起到了重要的生理功能,然而,NOS的表达及在亚细胞水平的定位以及相应的差异变化等都很不明确,本试验采用捕食应激模型,利用免疫组织化学方法和生化测定,检测心理性应激对大鼠脾脏iNOS活性的影响及探讨这种影响与应激动物免疫力下降之间的关系.结果表明iNOS免疫阳性细胞表达部位集中于脾脏的红髓和边缘区,白髓中几乎没有.与对照组相比,在应激1~12d的过程中,应激组大鼠脾脏内iNOS的活性逐渐升高,至d12最为显著(P<0.01).但在后期应激13~30d,脾内iNOS的表达又逐渐减少.生化测定结果表明,NOS和NO的含量变化与iNOS的活性变化相似,在心理性应激早中期较高,至d12最为显著(P<0.01),而到中后期则逐渐降低.结果提示,iNOS活性程度与动物心理应激程度密切相关;应激过程中大鼠脾脏内由于iNOS的活性增加导致产生过量的NO,这可能与应激导致大鼠免疫力下降有关.图1表2参10  相似文献   

5.
通过全氟辛烷磺酸(PFOS)28 d大鼠经口染毒评价PFOS肝损伤效应,探讨内质网应激在PFOS毒效应中的作用。Wistar大鼠随机分组,分别以0 mg·kg~(-1)、5 mg·kg~(-1)和10 mg·kg~(-1)PFOS灌胃染毒28 d。HE染色观察大鼠肝脏形态改变。ELISA法测定各组丙氨酸转氨酶(ALT)、天门冬氨酸转氨酶(AST)、碱性磷酸酶(ALP)和淀粉酶(AMY)含量变化。紫外分光光度法测定肝组织匀浆中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性变化。RT-PCR检测肝脏内质网应激标志蛋白表达水平。结果表明,PFOS造成大鼠体重降低、肝重增高(P0.05),组织切片显示肝细胞出现脂质沉积。PFOS不同剂量组大鼠ALT随暴露浓度增加,分别为(50.96±10.02)U·L~(-1)、(71.73±11.55)U·L~(-1),显著高于对照组(P0.05),AST、ALP含量与对照组相比显著上升(P0.05),高剂量组AMY水平为(833.46±63.05)U·L~(-1),与对照组相比显著降低(P0.05)。GSH-Px和SOD水平随PFOS浓度增加出现了显著降低(P0.05),而MDA水平显著升高(P0.05)。内质网应激标志蛋白表达均较对照组显著上升(P0.05)。以上结果说明PFOS可导致大鼠肝细胞损伤,其机制可能与内质网应激调控有关。  相似文献   

6.
热休克蛋白(HSP)参与蛋白质折叠、细胞膜转位和错误折叠蛋白质降解等过程,提高动物对环境的应激能力和适应能力。前期研究表明,多溴联苯醚-47(PBDE-47)对背角无齿蚌具有显著的氧化应激和急性毒性效应,为探讨PBDE-47慢性毒性效应;将背角无齿蚌随机分为对照组和PBDE-47处理组,处理组用3.36μg·L~(-1)浓度的PBDE-47进行处理,对照组用相同体积的二甲亚砜进行处理;克隆出AwHSP70基因,分析PBDE-47对AwHSP70表达的影响。结果显示,AwHSP70具有HSP70家族的标签序列,广泛分布于斧足、鳃、肝胰脏、闭壳肌、心脏、血淋巴和外套膜。PBDE-47处理可导致肝胰脏、鳃和血细胞中AwHSP70 mRNA水平显著升高。与对照组相比,PBDE-47处理组肝胰脏中AwHSP70 mRNA水平在1~15 d内增加2. 79倍(P<0.01)以上;鳃中AwHSP70 mRNA水平增加3.06倍(P<0.01)以上;血淋巴中AwHSP70表达增加1.81倍(P<0.05)以上。背角无齿蚌上调AwHSP70表达有助于增强动物对PBDE-47的耐受能力。  相似文献   

7.
以β-actin为内参基因,采用实时荧光定量聚合酶链式反应(PCR)技术,检测不同时间(12、24、48、96和192h)不同浓度(0.01、0.1、1、10、100、300μg·L-1)壬基酚(NP)处理下近江牡蛎(Crassostrea hongkongensis)鳃、外套膜和消化腺中HSC70和HSP70基因mRNA的表达水平。结果显示,0.01μg·L-1NP能诱导近江牡蛎鳃和消化腺中HSC70和HSP70基因显著高表达(P0.05)。随着NP处理浓度的升高,其表达水平逐渐升高,处理一定时间后100μg·L-1NP诱导近江牡蛎HSC70和HSP70基因表达量显著高于300μg·L-1NP诱导表达量(P0.05)。HSC70基因在鳃和消化腺中显著高表达峰值出现在96 h时,在外套膜中出现在48 h时;HSP70基因在鳃中显著高表达峰值出现在48 h时,在外套膜和消化腺中出现在24 h时。可见,近江牡蛎HSC70和HSP70基因对NP具有显著反应性。  相似文献   

8.
在实验室条件下,将驯化后的鲻鱼(Mugil cephalus)幼鱼〔体长(3.37±0.19)cm,体质量(0.36±0.02)g〕分别放在盐度为20(CK)、15、10、5和0的水体中饲养20 d,检测不同盐度和不同时间(试验0、5、10、15和20 d)鲻鱼幼鱼鳃丝、肌肉和肠3种组织中Na+-K+-ATP(NKA)酶活性和丙二醛(MDA)含量。结果表明,在正常生长环境盐度(CK)下鲻鱼幼鱼鳃丝、肠NKA酶活性及MDA含量均明显高于肌肉。在受到低盐度胁迫时不同组织的响应程度不同,鳃丝和肠NKA酶活性变化幅度高于肌肉,而MDA含量的变化则恰好相反。0~10 d时,处理组鲻鱼幼鱼鳃丝、肠道和肌肉NKA酶活性均显著高于对照组(P0.05),表明一定范围的低盐度(0~15)环境能激活和提高鲻鱼幼鱼NKA酶活性,增强其对低盐度环境的适应能力。0~5 d时,处理组3种组织内MDA含量均显著高于对照组(P0.05),且MDA含量总体随盐度降低而升高。随试验时间延长,试验组NKA酶活性以及MDA含量均降低并趋于稳定,与对照组之间差异减小,表现出较强的盐度适应能力,但NKA酶活性和MDA含量恢复到对照组水平所需时间与组织有关,具有组织器官的特异性和时序性。  相似文献   

9.
为探讨亚硝酸盐急性胁迫对中华绒螯蟹机体免疫力的影响,以及机体在胁迫过程中的应对策略,分别测定了幼蟹(平均体重3.25 g)在10、20、30、40 mg L-1亚硝酸盐暴露组和对照组中血细胞总数(Total hemocyte counts,THC)、超氧化物歧化酶(Superoxide dismutase,SOD)活力、丙二醛(Malodiadehyde,MDA)含量以及热休克蛋白70(Heatstress protein 70,HSP70)表达量在受胁迫2 d内的动态变化.结果表明:1)低浓度亚硝酸盐(10 mg L-1)胁迫组THC在胁迫3 h时显著高于对照组,肝胰腺中SOD活性在胁迫3 h和6 h时亦显著提高,表现出一定的"毒物兴奋效应".2)但随着暴露时间的延长和亚硝酸盐浓度的升高,幼蟹THC减少,肝胰腺SOD活性下降,而MDA含量升高.3)对照组中有少量的HSP70表达.幼蟹经10、20 mg L-1亚硝酸盐处理后,鳃组织中HSP70表达量在胁迫6 h后达到最大,而经30、40 mg L-1亚硝酸盐处理后,HSP70表达量在胁迫3 h后达到最大.各浓度组所诱导的HSP70最大表达量与水中亚硝酸盐的浓度呈正相关.以上结果说明亚硝酸盐胁迫可通过加剧组织中脂质过氧化的方式导致机体免疫力下降,肝胰腺中MDA的含量变化可作为亚硝酸盐胁迫的有效评价指标之一,而HSP70表达量的变化可作为早期预警指标应用于亚硝酸盐胁迫评价中.图2表1参36  相似文献   

10.
冷应激对健康雏鸡某些内分泌活动的影响   总被引:21,自引:4,他引:17  
以罗曼雄性雏鸡为试验对象,研究5d和10d龄健康雏鸡在低于正常饲养温度条件下,在一定时间内机体某些代谢激素的变化规律,结果表明:(1)5d龄雏鸡在两种低温情况下,血清三碘甲腺原氨酸(T3)变化显著,在冷应激最初几h内,T3先下降,至6h(15±1℃)和12h(10±1℃)又升高;血清四碘甲腺原氨酸(T4)变化不明显,在10±1℃情况下,在12h时显著降低;胰岛素(Ins)在两种低温情况下,均于2h时显著升高,而后呈波动性变化,(2)10d龄雏鸡在15℃±1℃条件下,T3在0.5~3h显著下降,至6h回升;T4在2h时显著升高(P<0.05);Ins在2h时升高(P>0.05),但3h时显著降低,而后又回升(3)血清皮质醇浓度均于冷应激后2h时有所升高,但差异不显著,而后呈波动性变化.  相似文献   

11.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

12.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

13.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

14.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

15.
An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.  相似文献   

16.
Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.  相似文献   

17.
Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.  相似文献   

18.
Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.  相似文献   

19.
20.
How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号