Conservation practitioners’ understanding of how to manage evolutionary processes

Both academics and practitioners consider a lack of knowledge about evolutionary theory to be a general barrier to effectively managing genetic diversity. However, it is challenging to judge practitioners’ level of understanding and how this influences their management decisions. Knowledge built through experience may be difficult for practitioners to articulate, but could nonetheless result in appropriate management strategies. To date, researchers have assessed only the explicit (formal) knowledge practitioners have of evolutionary concepts. To explore practitioners’ understanding of evolutionary concepts, it is necessary to consider how they might apply explicit and implicit knowledge to their management decisions. Using an online survey, we asked Australian practitioners to respond to 2 common management scenarios in which there is strong evidence that managing genetic diversity can improve outcomes: managing small, isolated populations and sourcing seeds for restoration projects. In describing their approach to these scenarios, practitioners demonstrated a stronger understanding of the effective management of genetic diversity than the definitions of the relevant concepts. However, their management of genetic diversity within small populations was closer to best practice than for restoration projects. Moreover, the risks practitioners described in implementing best practice management were more likely to affect their approach to restoration than translocation projects. These findings provide evidence that strategies to build the capacity of practitioners to manage genetic diversity should focus on realistic management scenarios. Given that practitioners recognize the importance of adapting their practices and the strong evidence for the benefits of actively managing genetic diversity, there is hope that better engagement by evolutionary biologists with practitioners could facilitate significant shifts toward evolutionarily enlightened management.     

Targeted gene flow for conservation

Anthropogenic threats often impose strong selection on affected populations, causing rapid evolutionary responses. Unfortunately, these adaptive responses are rarely harnessed for conservation. We suggest that conservation managers pay close attention to adaptive processes and geographic variation, with an eye to using them for conservation goals. Translocating pre‐adapted individuals into recipient populations is currently considered a potentially important management tool in the face of climate change. Targeted gene flow, which involves moving individuals with favorable traits to areas where these traits would have a conservation benefit, could have a much broader application in conservation. Across a species’ range there may be long‐standing geographic variation in traits or variation may have rapidly developed in response to a threatening process. Targeted gene flow could be used to promote natural resistance to threats to increase species resilience. We suggest that targeted gene flow is a currently underappreciated strategy in conservation that has applications ranging from the management of invasive species and their impacts to controlling the impact and virulence of pathogens.     

广州河涌水体中食蚊鱼肝脏性激素相关基因的表达水平研究

应用食蚊鱼细胞色素P450芳香化酶基因(CYP19α)、卵黄蛋白原基因(VTGα)和雌/雄激素受体基因(ERα/ARα)m RNA转录水平为指标,评价广州海珠涌和黄埔涌食蚊鱼受环境激素物质干扰产生雌/雄性化效应的现状。结果显示,海珠涌宝岗大道段(BG)、洪德路段(HD)和黄埔涌赤岗路段(CG)、苗艺路段(MY)采样点雌鱼性腺CYP19αm RNA表达水平显著降低。雌鱼肝脏VTGαm RNA的表达水平在夏冬两季CG点都显著升高,但在BG、HD和MY点的表达水平在冬季则显著下降;夏冬两季雌鱼雄激素受体ARαm RNA表达水平在各点都显著升高。雄鱼性腺CYP19αm RNA表达水平在各点都无明显差异,但CG点在夏季显著升高,而MY点在冬季则显著下降;雄鱼肝脏VTGα和雌激素受体ERαm RNA表达水平分别在各点都显著升高,但夏季MY点和冬季HD、MY各点无明显差异。结果表明,雌性食蚊鱼的VTGα和CYP19α基因受到不同程度的抑制,ERα较对照REF明显升高,表现出雄激素效应;雄性食蚊鱼VTGα和ERα转录水平较对照REF显著升高,CYP19α基因无显著性差异,表现出雌激素效应。生活在广州海珠涌和黄埔涌中的食蚊鱼受雌/雄激素物质干扰明显,表明河涌中环境激素污染严重。     

悬浮物对褐牙鲆抗氧化酶活性及相关基因表达的影响

为探究褐牙鲆(Paralichthys olivaceus)幼鱼抗氧化系统酶活力及相关基因表达在悬浮物胁迫下的变化情况,设计了浓度为5 000、10 000 mg·L-1悬浮物水体对褐牙鲆(14.53 cm±1.58 cm)肌肉、肝脏、鳃及血液总超氧化物歧化酶(T-SOD)、谷胱甘肽转移酶(GST)、过氧化氢酶(CAT)酶活力及SOD2、GST、CAT的mRNA转录水平表达变化情况。结果显示:在悬浮物胁迫24 h或者48 h时,4种组织3种酶活力具有升高的趋势(P0.05);4种组织的T-SOD酶活力在96 h均高于对照组(P0.05),肌肉、鳃丝及血液中SOD2基因相对表达量96 h实验组低于对照组(P0.05);肌肉中CAT酶活力呈现先升高再降低趋势,鳃中CAT基因相对表达量呈现先降低、再升高、再降低的趋势;肝脏、鳃、血液中GST酶活力在悬浮物胁迫下呈现升高趋势,4种组织GST基因相对表达量在12~24 h时呈现升高趋势。研究表明:悬浮物对褐牙鲆抗氧化酶活力及相关基因的表达具有一定的影响,血液中3种酶活力变化幅度最大,鳃中3种基因相对表达水平变化幅度最大,这与血液及鳃参与呼吸作用过程有关;抗氧化酶活性及基因相对表达变化趋势并不完全一致。本研究可为揭示褐牙鲆应对悬浮物胁迫的耐受机制及褐牙鲆耐悬浮物品种选育提供基础数据。     

MUCT短程硝化和反硝化除磷系统中Candidatus Accu- mulibacter的代谢活性和菌群结构

采用实现亚硝酸型硝化的MUCT工艺处理低C/N实际生活污水,在短程硝化的基础上实现反硝化除磷.研究短程硝化建立与破坏过程中,亚硝酸盐积累率的变化对系统除磷性能及Candidatus Accumulibacter菌群结构的影响.结果表明:MUCT除磷以反硝化除磷为主,平均反硝化除磷率高达88%.磷去除率与亚硝酸盐积累率具有很好的正相关性.短程硝化阶段磷的平均去除率比全程硝化阶段高30%以上,证明了亚硝酸盐更适合作为低C/N比污水反硝化除磷的电子受体.以多聚磷酸盐激酶基因(ppk1)作为遗传标记,采用实时荧光定量PCR方法考察不同亚硝酸盐积累率下Accumulibacter的丰度、各主要进化分支的菌群结构和相对丰度.当系统处于全程硝化状态时,存在少量以硝酸盐为电子受体的Acc-I型反硝化聚磷菌,低于总Accumulibacter的5%;当系统进入短程硝化状态后,Acc-I逐渐消失.运行期间以亚硝酸盐作为电子受体进行反硝化除磷的Acc-IID始终是优势聚磷菌,达到总Accumulibacter的92%以上,甚至接近100%,保证了亚硝酸型反硝化除磷的稳定运行,亚硝酸盐浓度是影响其丰度变化的重要因素.     

Human serum paraoxonase gene polymorphisms and association with chronic symptoms of pesticide toxicity in Indian farmers

The association between PON1 (serum paraoxonase) genotype and symptoms of pesticide toxicity was examined in a total of 268 farm workers in Andhra Pradesh, India. Approximately 140 of the farm workers who did not report at least two of the symptoms of chronic toxicity, such as abdominal pain, nausea, dizziness, headache, drowsiness, fatigue, tremors of fingers, numbness, or limb weakness were categorized as controls. The remaining 128 farmers showed 2 or more of the above symptoms. All the farm workers were genotyped for polymorphisms of PON1 gene at amino acid positions 55 (exon 3) and 192 (exon 6). A decrease in the percentage of high-activity genotypes at both L55M and Q192R was observed in the farm workers reporting symptoms of pesticide toxicity. When combined genotype distribution at both exons was analyzed, a marked increase in the percentage of low-activity genotypes LLQQ, LMQQ, MMQQ, and MMQR was also observed in symptomatic farmers compared to controls. Age, working years, smoking, duration of exposure, and alcoholism were not statistically significant when compared to symptoms of chronic toxicity. Our findings suggest that L55M and Q192R gene polymorphisms influence the variable susceptibility of farmers to pesticide; and thus may be considered a useful biomarker of genetic susceptibility in assessing an individual's risk of pesticide exposures.     

磷酸三(2,3-二氯丙基)酯阻燃剂对稀有鮈鲫的毒性效应

为研究新型阻燃剂磷酸三(2,3-二氯丙基)酯(TDCPP)的毒性效应,以稀有鮈鲫(Gobiocypris rarus)为实验生物,采用半静态实验方法,分别进行96 h和28 d的染毒,研究TDCPP对稀有鮈鲫的急性毒性和慢性毒性效应,并通过对稀有鮈鲫脑组织中与神经纤维的生长、发育、轴突再生等相关基因mRNA表达量的检测,初步探讨了TDCPP的神经毒性作用。结果表明：TDCPP对稀有鮈鲫的96 h-LC₅₀为2.99(2.20～3.38) mg·L^-1,根据化学物质对鱼类毒性分级标准TDCPP属于剧毒性。经0.9、1.5、2.1和2.7 mg·L^-1 TDCPP染毒28 d,与对照组相比,暴露组稀有鮈鲫肝脏及脑组织中SOD和GSH-Px的活性均受到抑制,且随着TDCPP的暴露浓度增加,其抑制作用显著增强;暴露组稀有鮈鲫脑组织中与神经纤维的生长、发育相关的微管蛋白α/β、神经丝NF-M以及关键蛋白GAP-43等基因的mRNA表达量,与对照相比均发生显著下调。可知,TDCPP暴露可以诱发稀有鮈鲫神经毒性作用。     

典型POPs的生物降解修复技术研究与发展

生物吸附与降解是解决持久性有机污染物（POPs）最有潜力的方法之一,有必要介绍利用微生物把目标污染物转化为易降解的物质甚至矿化的POPs修复原理及其技术。对此,概述了近年来国内外基于微生物通过膜融合、胞质融合和核融合形成能够降解POPs的杂种细胞的细胞融合技术;基于降解性质粒的相容性,把能够降解不同污染物的质粒组合到一个菌种中,形成多质粒的新菌种,使微生物由于代谢途径的改变能够矿化POPs的基因工程菌构建技术;基于通过某些载体把酶固定于其中实现活性稳定、可以回收及可重复利用的酶固定化技术,以及基于降解菌活性酶分子亚基置换、降解菌活性酶的定点突变、降解酶的体外定向进化这几方面的酶构建技术;进一步分析基于分子生物学提高POPs生物修复能力的原理,指出经生物技术改造的工程菌和固定化酶未能进入实际应用的障碍所在。以多溴联苯醚（PBDEs）的微生物细胞吸收和降解机理作为典型POPs生物修复的案例,强调生物降解的过程强化需要建立多尺度上功能方面的适合;提出了分子生物学与基因工程学的结合在解决POPs环境污染方面未来的基础科学问题与研究思路。综合上述,典型POPs的生物修复技术的构建需要考虑宏观污染物协同降解的工艺理论,在基因水平、分子水平、反应器水平及工程水平上追求更高功能方面的适合。     

白洋淀水陆交错带N20还原酶基因（nosE）与反硝化活性的垂直分布研究

为深入剖析水陆交错带N2O释放热区的机理,选择白洋淀一处典型水陆交错带为研究对象。通过对其纵剖面（0～80cm）分层土壤样品的理化指标、反硝化速率（DNR）、N2O产生速率及N2O还原酶基因（NosZ）丰度和多样性的分析发现,在水陆交错带陆域纵剖面中,表层土壤（0～10cm）的反硝化速率（DNR）和N2O产生速率均最高,分别为65．8和9．41nmol·g^-1·h^-1（以N及dw计）;表层（0～10cm）和亚表层（10～20cm）土壤的nosZ基因丰度最高（分别为1．00×10^10genecopies·g^-1dw和9．23×10^9genecopies·g^-1dw）且没有显著性差异（p〈0．05）。生物多样性指数表明,表层土壤的nosZ基因生物多样性高于底层;在系统发育树中,表层和底层土壤的nosZ基因序列并没有明显的界限。Pearson相关性分析表明,在典型水陆交错带陆域纵剖面中,nosZ基因丰度与N2O／N2O＋N2）呈负相关关系（r=0．766,p〈0．05）,表明在水陆交错带区域nosZ基因丰度是N2O转化的指示指标。     

微囊藻毒素对真菌和哺乳动物细胞毒害效应的研究

主要探讨微囊藻毒素对真菌和哺乳动物细胞的毒害效果,以及其作为水体生理毒害评价模式细胞的可能。通过毒性试验和单细胞凝胶电泳实验,利用栗酒裂殖酵母细胞（S.pombe）,人肝癌细胞（HepG2）和人脑星形胶质母细胞癌细胞（U87）3种生物模型评估MC对细胞DNA的损伤以及对细胞内氧化自由基水平的影响。并利用栗酒裂殖酵母的基因缺失体,判断MC所诱导的酵母细胞氧化应激路径。研究表明MC通过氧化路径诱导DNA损伤;缺失wis1△和pap1△基因的S.pombe细胞无法诱导ROS生产,wis1△和pap1△缺失型S.pombe细胞在40 mg·L-1-1MC暴露24 h下细胞增殖率仅下降7.3%、7.7%;氧化损伤是MC损伤S.pombe的主要方式;HepG2细胞和U87细胞较S.pombe细胞适于研究、评估MC的毒性。