东北林区半人工养殖林蛙对当地自然生态保护影响的调查与分析

应用资料收集法和实地调查法,调查、评估并分析了东北林蛙养殖区域自然生态变化趋势、东北林蛙养殖业从业人员行为的影响及养殖业发展的可持续性.结果表明开展林蛙半人工养殖的区域几乎全部是自然生态状况良好、具有重要保护价值的区域;林蛙半人工养殖方式极大地提高了区域性森林生态系统中林蛙的数量,进而将导致自然生态系统发生一系列变化,这些变化对自然生态状况的影响有利有弊,并存在不确定性;林蛙养殖从业人员的从业行为或行为倾向,既有有利于当地自然生态保护的一面,也有不利于当地自然生态保护的隐患.在调查与分析的基础上,提出了如下建议:加强林蛙资源本底调查,坚持对林蛙半人工养殖区域自然生态变化的监测和研究,统一林蛙半人工养殖区域各经营活动的经营权,研究制定东北林蛙半人工养殖技术规范,引导从业人员规范操作等.     

基于原核表达的副溶血性弧菌类毒素疫苗对海水鱼类免疫保护作用

目的:实现副溶血性弧菌溶血毒素基因tdh克隆与表达,并以表达产物TDH作免疫原,研究其对海水鱼免疫活性的影响.方法:PCR扩增tdh;构建重组质粒(pET-28-TDH);IPTG诱导表达;SDS-PAGE检测:以纯化的TDH融合蛋白脱毒为类毒素免疫原免疫健康真鲷,测定其血清中过氧化氢酶(CAT)、酸性磷酸酶(ACP)、超氧化物歧化酶(SOD)和碱性磷酸酶(AKP)活性变化;用副溶血性弧菌病原攻毒,检测免疫保护作用.结果:tdh基因成功克隆并表达;表达蛋白相对分子量为21 kDa,证实为TDH蛋白;类毒素免疫真鲷后,其血清中总超氧化物歧化酶(T- SOD)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)和过氧化氢酶(CAT)活力在注射后48h、24h、24h、2Ah达到最高,最高点分别高于对照组77％、328％、75％、381％;72 h后均恢复至对照组水平.结论:类毒素对真鲷免疫系统具有明显的刺激作用;类毒素免疫后对攻毒的真鲷保护率达50％.     

考虑农业保护地因素下的红火蚁适生性分析

为明确外来入侵物种红火蚁Solenopsis invicta在我国的适生区分布格局及农业保护地对其分布的影响,本研究基于集成模型预测了红火蚁的潜在分布,并结合农业保护地的面积占比情况进行分析。结果显示,集成模型TSS、ROC值在0.85、0.95左右,预测结果可靠;温度和降水是影响红火蚁分布的关键环境变量;在历史气候条件下,红火蚁适生区将遍布到中国的28个省(市、自治区);考虑农业保护地因素,山东省、云南省、北京市、新疆维吾尔自治区、辽宁省和黑龙江省的部分地区适生区等级升高。     

Escherichia coli populations in unpredictably fluctuating environments evolve to face novel stresses through enhanced efflux activity

There is considerable understanding about how laboratory populations respond to predictable (constant or deteriorating environment) selection for single environmental variables such as temperature or pH. However, such insights may not apply when selection environments comprise multiple variables that fluctuate unpredictably, as is common in nature. To address this issue, we grew replicate laboratory populations of Escherichia coli in nutrient broth whose pH and concentrations of salt (NaCl) and hydrogen peroxide (H₂O₂) were randomly changed daily. After ~170 generations, the fitness of the selected populations had not increased in any of the three selection environments. However, these selected populations had significantly greater fitness in four novel environments which have no known fitness‐correlation with tolerance to pH, NaCl or H₂O₂. Interestingly, contrary to expectations, hypermutators did not evolve. Instead, the selected populations evolved an increased ability for energy‐dependent efflux activity that might enable them to throw out toxins, including antibiotics, from the cell at a faster rate. This provides an alternate mechanism for how evolvability can evolve in bacteria and potentially lead to broad‐spectrum antibiotic resistance, even in the absence of prior antibiotic exposure. Given that environmental variability is increasing in nature, this might have serious consequences for public health.     

Verticillium dahliae LysM effectors differentially contribute to virulence on plant hosts

Chitin‐binding lysin motif (LysM) effectors contribute to the virulence of various plant‐pathogenic fungi that are causal agents of foliar diseases. Here, we report the LysM effectors of the soil‐borne fungal vascular wilt pathogen Verticillium dahliae. Comparative genomics revealed three core LysM effectors that are conserved in a collection of V. dahliae strains. Remarkably, and in contrast with the previously studied LysM effectors of other plant pathogens, no expression of core LysM effectors was monitored in planta in a taxonomically diverse panel of host plants. Moreover, targeted deletion of the individual LysM effector genes in V. dahliae strain JR2 did not compromise virulence in infections on Arabidopsis, tomato or Nicotiana benthamiana. Interestingly, an additional lineage‐specific LysM effector is encoded in the genome of V. dahliae strain VdLs17, but not in any other V. dahliae strain sequenced to date. Remarkably, this lineage‐specific effector is expressed in planta and contributes to the virulence of V. dahliae strain VdLs17 on tomato, but not on Arabidopsis or N. benthamiana. Functional analysis revealed that this LysM effector binds chitin, is able to suppress chitin‐induced immune responses and protects fungal hyphae against hydrolysis by plant hydrolytic enzymes. Thus, in contrast with the core LysM effectors of V. dahliae, this lineage‐specific LysM effector of strain VdLs17 contributes to virulence in planta.     

del Nido心脏停搏液在主动脉夹层手术中的心肌保护效果

摘要 目的：探讨del Nido心脏停搏液在主动脉夹层手术中的心肌保护效果。方法：2015年2月到2020年6月选择在本院进行急诊手术的Stanford A型主动脉夹层的150例患者,入院后根据术中采用的心脏停搏液的不同分为两组 del Nido组与对照组各75例,所有患者都实施大血管外科手术,由同一组医师团队完成手术。Del Nido组给予del Nido心脏停博液灌注,对照组给予改良St. Thomas液灌注,记录心肌保护效果。结果：所有患者完成手术,两组的体外循环时间、停循环时间、阻断主动脉时间对比差异无统计学意义(P>0.05),del Nido组的灌注次数、总灌注时间、停博液晶体总量与对照组对比,差异有统计学意义(P<0.05)。Del Nido组的机械通气时间、ICU停留时间、术后住院时间短于对照组(P<0.05)。两组术后1 d的血清 cTnⅠ高于术前(P<0.05),del Nido组低于对照组(P<0.05)。两组术后7 d的院内死亡、心律失常、开胸止血、肾功能不全、肝功能不全等发生率对比差异无统计学意义(P>0.05)。结论：del Nido心脏停搏液在主动脉夹层手术中的能更好地发挥心肌保护效果,且不增加术后并发症的发生,减少灌注次数、总灌注时间,有利于促进患者康复。     

Verbenone-releasing flakes protect individual Pinus contorta trees from attack by Dendroctonus ponderosae and Dendroctonus valens (Coleoptera: Curculionidae, Scolytinae)

1 In a study site in interior northern California, twenty individual lodgepole pines Pinus contorta were sprayed with a suspension of DISRUPT Micro‐Flake^® Verbenone (4,6,6‐trimethylbicyclo(3.1)hept‐3‐en‐2‐one) Bark Beetle Anti‐Aggregant flakes (Hercon Environmental, Emigsville, Pennsylvania) in water, with sticker and thickener, from ground level to a height of 7 m. Twenty trees sprayed with just water, sticker and thickener served as controls. All trees were baited immediately after spraying with mountain pine beetle Dendroctonus ponderosae aggregation pheromone lures, and lures were refreshed after 4 weeks. 2 Trees treated with verbenone had significantly lower attack density by D. ponderosae than controls at 2, 4, 6 and 8 weeks after application of flakes. 3 None of the treated trees was attacked by red turpentine beetle Dendroctonus valens, whereas control trees averaged nearly two D. valens attacks per tree, 8 weeks after treatment. 4 A dry frass index, used to predict ultimate tree mortality, was significantly higher in control trees than treated trees for all four sampling intervals. This index proved to be a significant predictor of ultimate tree mortality. 5 Ten months after application, treated trees showed significantly lower mortality than control trees.     

外来树种桉树引种的景观生态安全格局

以大面积桉树引种区云南省澜沧县为研究区,以自然栖息地和生物多样性的整体保护为目标,利用最小累积阻力模型开展了桉树引种的景观生态安全格局的定量研究.结果表明:(1)基于GIS技术和“成本距离加权”制图分析工具,将生物和景观等综合因素融入最小累积阻力模型,把“源”扩展的生态过程与景观格局结合起来,应用于桉树引种的景观生态安全格局构建中是可行的.(2)选择次生常绿阔林为保护“源”,地表覆盖类型、海拔、坡度、土壤质地和公路等为阻力因子,建立最小累计阻力面,识别了廊道、辐射道和战略点等生态安全格局组分;用最小累积阻力阈值划分了生态缓冲区、生态过渡区、生态边缘区、农业耕作区和居民生活区等生态功能区,并界定桉树禁止种植区和桉树可种植区,最终组合成两个方案的中级和高级景观生态安全格局.方案一,中级和高级安全水平的桉树可种植区面积分别占研究区面积的33.48％和19.27％.方案二,中级和高级安全水平的桉树可种植区面积分别占研究区面积的28.37％和15.17％.(3)从“源”的扩展效果、保护广度、管理成本、难易程度及生态环境和经济社会发展要求等方面评价,认为方案二的中级安全水平格局能够相对满足澜沧县对生态、经济发展的要求.研究结果为制定研究区生态安全策略提供参考.     

Effects of food deprivation on expression of growth hormone receptor and proximate composition in liver of black seabream Acanthopagrus schlegeli

The effects of food deprivation on the hepatic level growth hormone receptor (GHR) were investigated in black seabream (Acanthopagrus schlegeli) both at the protein level (by radioreceptor assay) and at the mRNA level (by ribonuclease protection assay). Serum levels of growth hormone (GH) and triiodothyronine (T₃) were also measured. Condition factor and hepatic proximate composition of the fish were also assessed. Significant decrease in hepatic GHR binding was recorded as early as on day 2 of starvation. On day 30 this decrease was even more pronounced, with the level in the starved fish reaching less than 20% the fed control level. A concomitant decrease in the hepatic GHR mRNA content was also noted during this period, with a progressive decrease from day 2 to day 30 of starvation. The extent of decrease in the mRNA content was less pronounced than the decrease in receptor binding, with the hepatic GHR mRNA content in the day 30 starved fish representing approximately 30% of the level in the fed control. In large contrast, serum GH level increased progressively during starvation. After 30 days of starvation, serum GH levels in the starved fish were more than three times the concentration found in the fed control. Serum T₃ levels, on the other hand, decreased during starvation, with the difference reaching significance on day 15 and day 30. After 30 days of starvation, serum T₃ levels in the starved fish were only approximately 40% the concentration found in the fed control. The hepatic lipid content exhibited an increasing trend during starvation. On day 30 the hepatic lipid content of the starved fish had doubled the level found in the fed control. However, the hepatic protein content did not exhibit much change during starvation. There was also a minor decrease in the moisture content of the liver during starvation, but the condition factor of the fish as a whole registered a gradual decrease during the course of food deprivation.     

Cantaloupe line CZW-30 containing coat protein genes of cucumber mosaic virus,zucchini yellow mosaic virus,and watermelon mosaic virus-2 is resistant to these three viruses in the field

Cantaloupe line CZW-30 containing coat protein gene constructs of cucumber mosaic cucumovirus (CMV), zucchini yellow mosaic potyvirus (ZYMV), and watermelon mosaic virus 2 potyvirus (WMV-2) was investigated in the field over two consecutive years for resistance to infections by CMV, ZYMV, and/or WMV-2. Resistance was evaluated under high disease pressure achieved by mechanical inoculations and/or natural challenge inoculations by indigenous aphid vectors. Across five different trials, homozygous plants were highly resistant in that they never developed systemic symptoms as did the nontransformed plants but showed few symptomatic leaves confined close to the vine tips. Hemizygous plants exhibited a significant delay (2–3 weeks) in the onset of disease compared to control plants but had systemic symptoms 9–10 weeks after transplanting to the field. Importantly, ELISA data revealed that transgenic plants reduced the incidence of mixed infections. Only 8% of the homozygous and 33% of the hemizygous plants were infected by two or three viruses while 99% of the nontransformed plants were mixed infected. This performance is of epidemiological significance. In addition, control plants were severely stunted (44% reduction in shoot length) and had poor fruit yield (62% loss) compared to transgenic plants, and most of their fruits (60%) were unmarketable. Remarkably, hemizygous plants yielded 7.4 times more marketable fruits than control plants, thus suggesting a potential commercial performance. This is the first report on extensive field trials designed to assess the resistance to mixed infection by CMV, ZYMV, and WMV-2, and to evaluate the yield of commercial quality cantaloupes that are genetically engineered.