Bias in the effect of habitat structure on pitfall traps: An experimental evaluation

Habitat structure has been implicated as a source of bias for pitfall-trap data but most evidence is observational or anecdotal. This study used an experimental approach to quantify biases due to habitat structure. In a randomized block design, I manipulated native grassland to create three types of habitat structure and measured pitfall-trap catches of grassland ants. Small patches of modified habitat were surrounded by otherwise unmodified grassland with the assumption that population density remained unaffected by the modification and that the effects observed were due to changes in trappability. I assessed magnitude, direction, predictability, and consistency of bias for the following types of data: population abundance for single species, relative abundance among species, species composition of assemblages, and species richness. The magnitude of the bias in population abundance was large for most species. However, since the direction of the bias varied predictably with habitat structure, pitfall-trap data can be used to judge differences in population abundance in some situations. The magnitude of the bias in relative abundance was less than for abundance. However, there was inconsistency in the direction and magnitude of bias among species. Thus, interpretation of relative abundance data in pitfall-trap studies may be compromised. Species richness and species composition were biased by habitat structure but were affected significantly only when the groundcover was very dense, suggesting a threshold effect of habitat structure. To help to interpret survey data, pitfall-trap studies should routinely measure attributes of habitat structure and incorporate an experimental component to characterize the bias.     

Photoacoustic imaging of the human placental vasculature

Minimally invasive fetal interventions require accurate imaging from inside the uterine cavity. Twin‐to‐twin transfusion syndrome (TTTS), a condition considered in this study, occurs from abnormal vascular anastomoses in the placenta that allow blood to flow unevenly between the fetuses. Currently, TTTS is treated fetoscopically by identifying the anastomosing vessels, and then performing laser photocoagulation. However, white light fetoscopy provides limited visibility of placental vasculature, which can lead to missed anastomoses or incomplete photocoagulation. Photoacoustic (PA) imaging is an alternative imaging method that provides contrast for hemoglobin, and in this study, two PA systems were used to visualize chorionic (fetal) superficial and subsurface vasculature in human placentas. The first system comprised an optical parametric oscillator for PA excitation and a 2D Fabry‐Pérot cavity ultrasound sensor; the second, light emitting diode arrays and a 1D clinical linear‐array ultrasound imaging probe. Volumetric photoacoustic images were acquired from ex vivo normal term and TTTS‐treated placentas. It was shown that superficial and subsurface branching blood vessels could be visualized to depths of approximately 7 mm, and that ablated tissue yielded negative image contrast. This study demonstrated the strong potential of PA imaging to guide minimally invasive fetal therapies.      

不同温度、气体微环境对红托竹荪干品储藏品质的影响

本研究针对红托竹荪干品在储藏过程中易发生褐变、降低商品性问题,探究了不同储藏条件(温度、气体微环境)对红托竹荪干品储藏品质的影响。以红托竹荪干品为原材料,考察了在气体微环境(空气、N₂、CO₂和脱氧)和不同储藏温度(5、25和45 ℃)下红托竹荪干品储藏品质的动态变化。在60 d的储藏期内,所有样品的褐变指数、剪切力、多酚氧化酶、过氧化氢酶、总酚、还原糖和5-羟甲基糠醛含量均增加,游离氨基酸、白度值、复水比均降低。与25、45 ℃相比,以上指标在5 ℃条件下均表现最优,5 ℃储藏条件下呈味氨基酸和挥发性成分指标更接近于0 d;在不同气体微环境比较下,CO₂储藏环境下干品品质保持最好,通过综合评分得出5 ℃低温结合CO₂充气条件下干品品质最优,其次为N₂结合5 ℃低温。结合经济成本,5 ℃低温结合CO₂或N₂充气可以作为红托竹荪干品延长货架期的推荐储藏技术。     

拉萨河中上游夏秋季纤毛虫群落时空变动及其与环境的关系

为揭示中国西藏高原河流浮游纤毛虫群落结构特征及与水环境的关系,于2015—2016年的8月和11月,利用25号浮游生物网,分别在拉萨河中上游共8个代表性采样点,共采集64个水样。物种鉴定采用活体观察和固定染色相结合的方法。共鉴定出纤毛虫91种,夏季49种,各样点物种数由小到大依次为:S2S4S8S5S1S3=S7S6。秋季64种,各样点物种数由小到大依次为:S4S3=S1=S2=S5S8S6=S7。夏季各样点丰度为1.2×10~4—5.6×10~5个/L,秋季各样点丰度在1.2×10~4—2.6×10~5个/L之间。夏、秋季的优势种均为12种且优势种组成与分布不同,表现该流域纤毛虫存在明显的时空差异;群落结构分析显示:纤毛虫群落结构简单,物种组成多样性低而分布均匀;纤毛虫营养功能结构分析表明,夏季B、S类群的物种丰富度低于秋季;相关分析表明,总磷和总氮是影响夏季纤毛虫物种多样性的主要环境因子,并且浊度、NH_4-N和NO_3-N是影响秋季纤毛虫的主要环境因子。     

重组hPRL-1的表达纯化及其理化和酶学性质研究

目的:表达纯化hPRL-1重组蛋白,分析其理化性质及酶学特性。方法:热激法将重组pET15b质粒转化入E.coli BL21中,IPTG诱导表达出His-tagged hPRL-1蛋白。使用Ni-NTA亲和层析法结合Mono Q离子交换层析法纯化。用SDS-PAGE法和Western Blot法进行表达情况的定性定量分析,并使用HPLC法鉴定蛋白纯度,计算出蛋白分子量,圆盘等电聚焦电泳分析重组蛋白等电点。比较分析以pNPP、4-MUP和DiFMUP为底物时的酶促反应动力学。同时以pNPP为底物测定酶的最适pH值;以4-MUP为底物测定酶的最适温度,分析探讨缓冲液离子强度与蛋白酪氨酸酶通用抑制剂钒酸钠对酶活力的影响。结果:以亲和层析和离子交换层析结合,可以纯化得到纯度约为95%的蛋白。测得蛋白分子量为24.54kD,等电点为9.11。以pNPP、4-MUP和DiFMUP为底物时Km分别为3720μmol/L,130μmol/L和50μmol/L。酶的最适pH值为7.6,最适温度为34℃。结论:纯化所得蛋白为目的蛋白hPRL-1;两步纯化相结合可以得到纯度较高的蛋白;三种底物特异性依次为DiFMUP>4-MUP>pNPP。     

以MyD88 TIR二聚化为靶点的抗炎抑制剂筛选模型的建立

MyD88是IL-1R/TLR受体超家族向细胞内转导胞外信号时募集到受体胞浆尾部的重要接头蛋白．由TIR结构域介导的MyD88分子同源二聚化是它招募到受体胞浆尾部的前提,然后二聚化的MyD88再募集下游信号分子,传递信号,引发促炎基因的表达．本研究旨在建立一种模型,以实现活细胞原位的、基于荧光信号变化的MyD88二聚化抑制物的高通量筛选．我们分别构建了MyD88 TIR与GFP和RFP的融合蛋白表达质粒,瞬时转染HeLa细胞,在488 nm激发光下,转染GFP-MyD88 TIR和RFP-MyD88 TIR细胞,检测到绿色荧光与红色荧光间的共振能量转移(FRET)．而当细胞转染GFP-MyD88 TIR和RFP或RFP-MyD88 TIR和GFP,因TIR二聚化不能实现,FRET效率受到严重影响．实验结果提示,依赖双阳性表达GFP-MyD88 TIR和RFP-MyD88 TIR的细胞株,检测不同化合物对于荧光FRET效率的影响,可以建立MyD88 TIR二聚化抑制药物的筛选模型．此外,我们构建了原核表达质粒,利用纯化的His-MyD88 TIR分别与GST或GST-MyD88 TIR蛋白进行体外结合实验,发现GST-MyD88 TIR(而非GST)可以与His-MyD88 TIR相互结合．结果的差异性提示,利用His-MyD88 TIR和GST-MyD88 TIR体外结合实验分析,可以进一步确定抑制物是否直接阻断了TIR的相互作用．结合真核细胞的荧光FRET阻断结果和原核表达的重组蛋白相互作用分析,可确定MyD88 TIR二聚化的抑制物．利用这一模型可以对商品化的小分子库、自行制备的天然产物组分进行广泛的筛选,从中获得有效抑制MyD88二聚化的化合物,参与对MyD88信号通路依赖的慢性炎症、自身免疫性疾病的药物治疗．     

FREUDEIA KASZAB, A NEWLY RECORDED GENUS AND A NEW SPECIES FROM CHINA (COLEOPTERA, TENEBRIONIDAE,TENTYRIINI)

报道中国鳖甲族1新纪录属及1新种:异颚弗鳖甲Freudeia heteromaxillaria sp.nov.,描述了新种的形态特征并附鉴别特征图和整体照片.新种模式标本保存于中国科学院西北高原生物研究所和河北大学博物馆.     

中国鳖甲族一新纪录属及一新种记述(鞘翅目,拟步甲科)

报道中国鳖甲族1新纪录属及1新种:异颚弗鳖甲Freudeia heteromaxillaria sp.nov.,描述了新种的形态特征并附鉴别特征图和整体照片。新种模式标本保存于中国科学院西北高原生物研究所和河北大学博物馆。     

Neotropical Copestylum (Diptera,Syrphidae) breeding in Agavaceae and Cactaceae including seven new species

We studied 42 species of saprophagous, Neotropical Copestylum (Diptera, Syrphidae) reared from decaying Cactaceae and Agavaceae. Thirty‐three species were reared during fieldwork in Bolivia, Costa Rica, Ecuador, Mexico, Peru, and Trinidad from 1998–2007. Nine species came from museum and private collections. Seven were new species. We describe these new species and the third stage larva and/or puparium and breeding sites of 40 species. Not described are two apparent species related to Copestylum apicale (Loew, 1866) reared from Cactaceae. Resolution of their status was beyond the scope of this paper but reference is made to their distinctive larval morphology. Based on early stage characters all reared species can be placed in ten species groups, all but three of which have been recognized previously on the basis of adult characters. A high level of congruence was found between adult and larval characters in terms of these species groups. Eight of the groups appear to be related closely and may represent a monophyletic lineage within Copestylum that has diversified in xeric habitats. Early stage morphology varied within and amongst groups but two trends in functional morphology are recognizable. One trend is towards feeding in watery decay and the other towards feeding in firmer decay. The latter trend is characterized by species that scoop food and use grinding mills in their head skeletons to break it up. They also have armoured thoraces with varying arrangements of sclerotized spicules or stiffened setae for gripping and protection during tunnelling, a short anal segment, and a short posterior breathing tube for protecting the openings. The former trend is characterized by species with opposite and contrasting features. They filter food and have well‐developed pre‐oral setal filters but they lack grinding mills or only have poorly developed grinding mills. They have reduced thoracic armature, elongate anal segments, and posterior breathing tubes which facilitates simultaneous feeding and respiration. Comparison with 23 Copestylum species reared from bromeliads (Bromeliaceae) suggests a common pattern of diversification in that species groups with the largest body sizes are more specialized.     

BR-TRG-Ⅰ型体腔热灌注治疗系统安全性评估的动物实验

目的探讨应用BR-TRG-I型体腔热灌注治疗系统进行持续循环腹腔热灌注治疗（continuous circulatory hyperthermic intraperitoneal perfusion treatment,CCHIP）对实验动物的生命体征、肝肾功能及内脏器官病理形态的影响。方法选用家猪作为实验动物,应用BR-TRG-I型体腔热灌注治疗系统建立CCHIP动物模型,分别用44℃、45℃的设定温度进行CCHIP。在CCHIP期间记录实验动物的生命体征变化;CCHIP前及治疗后1d、3d、7d和14d抽取外周血液保存备检;CCHIP结束后即刻及2周后处死动物,观察内脏器官的大体形态学改变,切取肝、肾、小肠等器官进行病理检查。结果44℃CCHIP持续1.5h对猪的生命体征、肝肾功能无明显影响,肝、肾、小肠等脏器损伤较轻,2周后恢复正常;45℃CCHIP持续1.5h对猪的生命体征影响严重,肝肾功能损害持续2周尚不能恢复正常,肝、肾、小肠等脏器病理损伤明显。结论44℃温度CCHIP1.5h安全可行,可以作为CCHIP的安全温度;45℃温度CCHIP1.5h可对实验动物肝肾功能造成严重损害,不适合作为CCHIP的治疗温度。