Strong founder effects and low genetic diversity in introduced populations of Coqui frogs

The success of non-native species may depend on the genetic resources maintained through the invasion process. The Coqui ( Eleutherodactylus coqui ), a frog endemic to Puerto Rico, was introduced to Hawaii in the late 1980s via the horticulture trade, and has become an aggressive invader. To explore whether genetic diversity and population structure changed with the introduction, we assessed individuals from 15 populations across the Hawaiian Islands and 13 populations across Puerto Rico using six to nine polymorphic microsatellite loci and five dorsolateral colour patterns. Allelic richness ( R _T) and gene diversity were significantly higher in Puerto Rico than in Hawaii populations. Hawaii also had fewer colour patterns (two versus three to five per population) than Puerto Rico. We found no isolation by distance in the introduced range, even though it exists in the native range. Results suggest extensive mixing among frog populations across Hawaii, and that their spread has been facilitated by humans. Like previous research, our results suggest that Hawaiian Coquis were founded by individuals from sites around San Juan, but unlike previous research the colour pattern and molecular genetic data (nuclear and mtDNA) support two separate introductions, one on the island of Hawaii and one on Maui. Coquis are successful invaders in Hawaii despite the loss of genetic variation. Future introductions may increase genetic variation and potentially its range.     

基于核酸侵入反应的基因突变检测方法研究进展

肿瘤靶向药物治疗需要检测特异性的基因突变。尽管已开发出多种基于模板扩增的基因突变检测方法,但由于存在扩增产物交叉污 染的风险,其应用受到极大限制。基于信号扩增的核酸侵入反应,由于不存在扩增产物污染的风险,并且具有良好的单碱基识别特异性, 非常适用于基因突变的检测。因此,一系列基于核酸侵入反应的基因突变检测方法应运而生。综述若干基于核酸侵入反应的基因突变检测 方法原理与应用研究。     

意大利苍耳入侵对本地植物群落物种多样性和稳定性的影响——以乌鲁木齐市为例

研究外来植物不同程度入侵对区域群落结构和植物群落物种多样性的影响对评价其对生态系统的危害具有重要意义。以入侵植物以意大利苍耳(Xanthium italicum)为主要研究对象,选择意大利苍耳危害较明显且分布面积较大的中国新疆乌鲁木齐市米东区为研究区域进行植物样方调查,以意大利苍耳和其共生的本地植物为切入点,以物种多样性指数、群落稳定性、群落可入侵性、影响程度指数、入侵植物的竞争优势和入侵强度来探究不同入侵程度下的本地植物群落物种多样性和群落稳定性的变化。结果表明:(1)与未入侵地相比,意大利苍耳轻度入侵显著增加了本地植物群落的物种多样性(P ＜ 0.05),而重度入侵显著降低了本地植物群落的物种多样性(P ＜ 0.05)。(2)在意大利苍耳入侵的群落中,群落稳定性由轻度入侵水平到重度入侵水平降低了25%,而群落可入侵性、意大利苍耳的竞争优势指数和入侵强度指数分别增加了77%、79%和83%。(3)在轻度入侵水平下,意大利苍耳对本植物群落物种多样性、群落稳定性和群落物种数的影响程度指数 ＜ 0,产生了积极影响;相反,在轻中度和重度入侵水平下意大利苍耳对本植物群落物种多样性、群落稳定性和群落物种数的影响程度指数 ＞ 0,产生了负面影响。(4)本地植物群落多样性与群落稳定性均呈正相关,但与群落可入侵性呈负相关(P ＜ 0.05)。(5)Shannon-Wiener指数对群落的稳定性的直接通经系数最大,为0.828;Simpson''s指数对群落可入侵性的直接通经系数最大,为0.932。由此可见,意大利苍耳在中度和重度入侵对植物群落结构产生巨大影响,而作为"一带一路"的核心和枢纽地带的新疆,将会对其脆弱的生态系统和土著物种的多样性造成不可估量的影响。应在入侵初期对其进行控制与铲除,防止意大利苍耳等有害外来入侵种的入侵和进一步扩散与蔓延。     

A Study on the Safety and Effects of Amorpha fruticosa Fruit Extract on Spontaneously Hypertensive Rats with Induced Type 2 Diabetes

Metabolic syndrome is characterized by a variety of diagnostic criteria: obesity, dyslipidemia, type 2 diabetes, and arterial hypertension. They contribute to the elevated risk of cardiovascular morbidity and mortality. The potential for Amorpha fruticosa L. (Fabaceae) to improve diabetes and metabolic disease is promising, based on in vitro tests. This is why a further investigation of the species is needed. Additionally, a toxicity review in relation to safety revealed that to date, there are no published data regarding the toxicity of A. fruticosa towards humans. This species could provide abundant and cheap resources because it is an aggressive invasive plant that grows almost unrestrictedly. The objective of this study was to evaluate the acute toxicity of a purified extract of A. fruticosa (EAF), and to assess its antioxidant, antihypertensive, and antihyperglycemic activity in streptozotocin-induced diabetic spontaneously hypertensive rats (SHRs). The EAF was slightly toxic (LD₅₀ = 2121 mg/kg, b.w.) when administered orally, and moderately toxic (LD₅₀ = 316 mg/kg, b.w.) at intraperitoneal administration, both in mice. The oral administration of EAF (100 mg/kg) for 35 days to SHRs caused significant decreases in the systolic pressure, blood glucose levels, and MDA quantity. It also increased the hepatic level of the endogenous antioxidant GSH, not only in diabetic SHRs, but also in the control group. An additional potential benefit to human health might be conferred through the environmental management of A. fruticosa based on its large-scale use for medicinal purposes, as this aggressive invasive species brings problems to natural habitats in many European countries.     

北京外来入侵植物的演变、分布特征及影响因素

【目的】北京外来入侵植物问题尤其突出,但其入侵和扩散的时空规律、影响因素尚不清楚,给制定相关管理措施带来挑战。本研究旨在厘清入侵植物在北京的动态规律及社会经济影响因素,为制定应对措施,有效防治外来入侵植物侵害提供信息和技术支撑。【方法】基于已有文献、专著和相关数据库信息,重新构建了北京外来入侵植物数据库,分析北京外来入侵植物的构成特征、入侵特点及危害,采用GIS、SPSS相关软件分析外来入侵植物的时间演变、空间分布特点,并与社会经济变量进行相关性分析。【结果】(1)北京外来入侵植物共101种,菊科植物最多;以一年生草本植物为主;原产地主要是美洲;主要入侵途径是人类活动造成的有意和无意引入;传播扩散活动多数依赖结实量大的特点;均会挤占本地种生态位;超过1/5属于国家重点关注防控的外来入侵植物;(2)不同时间阶段年均植物入侵数量具有极显著差异,经历了低、高和稳定3个阶段,入侵植物累计种数与历史事件累计次数、人口、货运量等社会经济因素呈极显著正相关;(3)空间分布格局中丰富度分布和密度分布的热点地区不同,入侵植物密度与常住人口密度、绿化覆盖率呈极显著相关。【结论】北京入侵植物的演变和分布特征除了受其自身入侵性的限制外,还受到社会经济发展及城市化等人类活动因素的影响,应预防、控制、消灭三管齐下,综合治理。     

No signs of Na+/K+‐ATPase adaptations to an invasive exotic toxic prey in native squamate predators

Invasions by exotic toxic prey, like the release of the South American cane toad (Bufo (Rhinella) marinus) to the toad‐free Australian continent in 1935, have been shown to result in massive declines in native predator numbers. Due to minor nucleotide mutations of the Na⁺/K⁺‐ATPase gene most Australian squamate predators are highly susceptible to cane toad toxin. However, in spite of this, predators like yellow‐spotted goannas (Varanus panoptes) and red‐bellied black snakes (Pseudechis porhyriacus) still persist in parts of Queensland where they, in some areas, have co‐existed with cane toads for more than 70 years. Here, we show that the amino acids of the Na⁺/K⁺‐ATPase enzyme in the two species do not provide toad toxin resistance, and hence the two Queensland predators are still highly susceptible to cane toad toxin. Both yellow‐spotted goannas and lace monitors (Varanus varius) have, however, been recorded avoiding feeding on cane toads in areas where they co‐exist with this toxic amphibian. Moreover, both varanids have also been shown to learn to avoid feeding on toads when first subjected to conditioned taste aversion. Such behavioural shifts may therefore explain why yellow‐spotted goannas and red‐bellied black snakes still exist in cane toad infested areas of Queensland. The process appears, however, to be unable to rapidly restore varanid populations to pre‐toad population numbers as even after 10 years of co‐existence with cane toads in the Northern Territory, we see no signs of an increase in yellow‐spotted goanna numbers.     

微创肺表面活性物质对呼吸窘迫综合征新生儿肝肾功能、氧合功能及呼吸功能的影响

目的:探讨微创肺表面活性物质(pulmonary surfactant,PS)对呼吸窘迫综合征新生儿氧合功能、肝肾功能及呼吸功能的影响。方法:选择2018年3月至2019年3月我院收治的66例新生呼吸窘迫综合征的患儿作为研究对象,并按照随机数字表法分为观察组(n=33)和对照组(n=33)。对照组患儿采取常规的治疗方式,观察组患儿则在对照组治疗基础上应用微创PS治疗。观察比较两组患儿的动脉血气指标、Ⅱ型肺泡细胞表面抗原(KL-6)、巨噬细胞移动抑制因子-1(MIF-1)、高迁移率族蛋白1(HMGB-1)、肝肾功能、氧合指数及呼吸机参数。结果:治疗后,两组的氧分压(PaO_2)、二氧化碳总量(TCO_2)、氧饱和度(SaO_2)均较治疗前显著增高;且观察组以上指标均高于对照组。两组的Ⅱ型肺泡细胞表面抗原(KL-6)、巨噬细胞移动抑制因子-1 (MIF-1)、高迁移率族蛋白1(HMGB-1)均较治疗前显著降低,且观察组的以上指标均低于对照组。两组的谷草转氨酶(AST)、谷丙转氨酶(ALT)、尿素氮(BUN)、肌酐(CRE)水平均较治疗前显著降低,且观察组的以上指标均明显低于对照组。观察两组的呼吸机参数和氧合指数,发现两组的吸入氧浓度(FiO_2)、吸气峰压(PIP)、呼吸末正压(PEEP)、氧合指数(PaO_2/FiO_2,OI)均较治疗前有所改善,且观察组的以上指标均要优于对照组(P0.05)。结论:应用微创PS治疗新生儿呼吸窘迫综合征的效果显著,能明显改善患儿的动脉血气指标、肝肾功能以及氧合功能,减轻炎症反应,并减少机械通气的参数。     

Hydrological responses of a valley‐bottom wetland to land‐use/land‐cover change in a South African catchment: making a case for wetland restoration

Valley‐bottom wetlands are valuable assets as they provide many ecosystem services to mankind. Despite their value, valley‐bottom wetlands are often exploited and land‐use/land‐cover (LULC) change results in trade‐offs in ecosystem services. We coupled physically based hydrological modeling and spatial analysis to examine the effects of LULC change on water‐related ecosystem services in the Kromme catchment: an important water‐providing catchment for the city of Port Elizabeth. LULC scenarios were constructed to match 5 different decades in the last 50 years to explore the potential effects of restoring the catchment to different historic benchmarks. In the Kromme catchment, valley‐bottom wetlands have declined by 84%, driven by key LULC changes: an increase in irrigated land (307 ha) and invasion by alien trees (336 ha). If the wetlands were restored to the relatively pristine extent and condition of the 1950s, riverflow could increase by approximately 1.13 million m³/a, about 6% of the current supply to Port Elizabeth. Wetland restoration would also significantly improve the catchment's ability to absorb extreme rainfall events, decreasing flood damage. We conclude that in the face of the water scarcity in this region, all ecosystem services, particularly those related to water flow regulation, should be taken into account by decision makers in charge of land zonation. Zonation decisions should not continue to be made on the basis of provisioning ecosystem services alone (i.e. food provision or dam yield). We recommend prioritization of the preservation and restoration of valley‐bottom wetlands providing water‐related ecosystem services to settlements downstream.     

澳大利亚外来入侵物种管理策略及对我国的借鉴意义

澳大利亚是一个岛状大陆,海洋运输业十分发达,通过贸易,旅游,运输等途径有意或无间引进有害外来物种的风险较大。澳大利亚政府高度重视外来入侵物种的管理工作,制定了《澳大利亚国家生物多样性保护策略》,针对外来杂草和通过压舱水载入的海洋外来入侵物种的管理制定了《国家杂草策略》,《杂草风险评价系统》和《压舱水指南》等法规和技术性文件,加强了对外来入侵物种的管理。本文简要介绍了澳大利亚外来入侵物种管理的有关策略和指南,并提出了我国在外来入侵物种管理方面的对策建议;（1）尽快建立相应的法规体系,实现外来入侵物种的依法管理;（2）加强机构建设,形成多部门的协调管理机制;（3）加强外来入侵物种管理制度的建设;（4）采取适当的引进预防,消除,控制和恢复措施;（5）开展科学研究,为外来入侵物种的管理提供科学依据;（6）制定教育和培训计划,提高公众意识。     

美国对入侵种的管理对策

外来种入侵是产生当前世界生物多样性危机的重要原因之一。目前外来种入侵问题已经引起人们的普遍关注。1999年2月美国联邦政府发布总统令,号召联邦政府机构执行人员防止外来入侵种所造成的严重环境威胁,指示有关职能部门行使职权阻止引入入侵种并且恢复本地种。总统令指示建立一个入侵物种理事会,并就理事会、联邦机构的职责做了相应界定。美国农业部等部门支持的入侵植物管理国家策略项目,提出了针对入侵种的三项国家目标一入侵种的预防、控制和本地种的恢复。国家管理策略的制定不同层次的人们提供了合作、教育和研究的机遇。美国政府部门以及有关社会团体已经就外来种入侵危害防范积极展开行动,包括制定标准防止入侵种进入,控制、根除入侵种,向民众进行有关外来种入侵的教育,增加财政年度预算等等。