Steller sea lion spatial‐use patterns derived from a Bayesian model of opportunistic observations

Despite acquisition of a substantial catalog of telemetry data from Steller sea lions (Eumetopias jubatus) over the past two decades, scientists still lack comprehensive regionally explicit knowledge about Steller sea lion habitat use. The Platforms of Opportunity data contain records of Steller sea lion sightings throughout the species’ entire range and have potential to fill gaps in knowledge about their spatial use; however, the data have not previously been used because effort (e.g., time spent surveying or area sampled) was not recorded when sightings were obtained. For this study a novel approach was used to overcome the lack of effort data through development of an effort index and a Bayesian negative binomial model. The model quantified Steller sea lion encounter rates and associated uncertainty within 15 × 15 km² grid cells across the species’ entire range. Year‐round, as well as breeding and nonbreeding season encounter rates were estimated. The results of this analysis identify several previously undocumented areas of high use by Steller sea lions, indicate that only 37% of Steller sea lion high‐use areas fall within designated critical habitat, and demonstrate that use of depth and distance from shore as indicators of Steller sea lion habitat is contraindicated.     

Properties of a Novel PBP2A Protein Homolog from Staphylococcus aureus Strain LGA251 and Its Contribution to the ��-Lactam-resistant Phenotype

Methicillin-resistant Staphylococcus aureus (MRSA) strains show strain-to-strain variation in resistance level, in genetic background, and also in the structure of the chromosomal cassette (SCCmec) that carries the resistance gene mecA. In contrast, strain-to-strain variation in the sequence of the mecA determinant was found to be much more limited among MRSA isolates examined so far. The first exception to this came with the recent identification of MRSA strain LGA251, which carries a new homolog of this gene together with regulatory elements mecI/mecR that also have novel, highly divergent structures. After cloning and purification in Escherichia coli, PBP2A_LGA, the protein product of the new mecA homolog, showed aberrant mobility in SDS-PAGE, structural instability and loss of activity at 37 °C, and a higher relative affinity for oxacillin as compared with cefoxitin. The mecA homolog free of its regulatory elements was cloned into a plasmid and introduced into the background of the β-lactam-susceptible S. aureus strain COL-S. In this background, the mecA homolog expressed a high-level resistance to cefoxitin (MIC = 400 μg/ml) and a somewhat lower resistance to oxacillin (minimal inhibitory concentration = 200 μg/ml). Similar to PBP2A, the protein homolog PBP2A_LGA was able to replace the essential function of the S. aureus PBP2 for growth. In contrast to PBP2A, PBP2A_LGA did not depend on the transglycosylase activity of the native PBP2 for expression of high level resistance to oxacillin, suggesting that the PBP2A homolog may preferentially cooperate with a monofunctional transglycosylase as the alternative source of transglycosylase activity.     

离子导入疗法对防治糖尿病视网膜病变及改善症状的临床研究

目的：探讨离子导入疗法对糖尿病视网膜病变患者进行护理的临床效果。方法：选取88例（122眼）糖尿病视网膜病变患者,随机分为照组和实验组,其中对照组44例（58眼）,给予常规护理治疗;实验组44例（64眼）,在对照组基础上采用离子导入疗法进行护理。观察患者视网膜改变、视力的改善及自觉症状改善情况。结果：实验组实施干预后,视网膜改变、视力的改善、自觉症状的改善显效率明显高于对照组,差异有统计学意义（P〈0．01）。结论：离子导入疗法有助于改善糖尿病视网膜病变患者眼底血液循环。促进出血点吸收、改善临床症状,操作简单易行,患者易于接受。     

Personality and body condition have additive effects on motivation to feed in Zebra Finches Taeniopygia guttata

Several hypotheses have been proposed to account for the adaptive evolution of personality, defined as inter‐individual differences in behaviour that are consistent over time and across situations. For instance, the ‘pace‐of‐life syndrome’ hypothesis suggests that personality evolved as a behavioural correlate of life‐history trajectories that vary within populations. Thus, proactivity, corresponding to higher exploratory tendencies or higher boldness levels, has been linked to higher productivity or mortality rates. However, the extent to which proactivity is associated with a higher motivation to forage remains poorly understood. Moreover, although personality and its effects on foraging behaviour are usually considered to be independent of any motivational or nutritional state, few studies so far have challenged this. Here we show that personality traits, both individually or combined using a principal component analysis, and body condition have additive effects on latency to feed following food deprivation in the Zebra Finch Taeniopygia guttata, with personality accounting for 41% and body condition for about 20% of the total variation in latency to feed. In accordance with the pace‐of‐life syndrome hypothesis, latency to feed was negatively related to the degree of proactivity and positively related to body condition. Thus, proactive individuals and individuals in poorer condition were quicker to start feeding after a period of food deprivation. The absence of a significant interaction between personality and body condition further suggests that the effect of personality was independent of body condition. We discuss the relevance of our results in relation to the different factors influencing foraging in birds. Moreover, we place our results within a life‐history framework by emphasizing the correlated evolution of life‐history traits and personality.     

基于比较基因组学的高地芽孢杆菌6ww6分子标识筛选及其快速鉴定

【目的】高地芽孢杆菌(Bacillus altitudinis) 6ww6是一株根际耐盐促生菌,可以作为微生物肥料的优选菌种。为了加强菌种知识产权保护,建立菌株快速检测方法。【方法】本研究通过基因组比对分析、TBLASTn检索、NR库检索验证并剔除有其他同源的结果序列,最终得到菌株6ww6的孤儿基因,设计引物进行PCR鉴定。【结果】筛选出5个特异性基因J939_13195、J9319_05960、J9319_13355、J9319_05965和J9319_13350。引物5960F和5960R可以单一性扩增出菌株6ww6的目的基因J9319_05960,确定其为菌株6ww6的特异性分子标识。【结论】本研究确定了菌株6ww6的唯一性身份编码,建立了以比较基因组学和孤儿基因为基础的菌株水平上的鉴定方法。该方法具有快速、精确、能鉴定到菌株水平的优点,对于有价值微生物的知识产权保护提供了有力的抓手。     

中国兽类一新纪录白尾高山䶄及西藏、湖北和四川兽类各一省级新纪录

在最近几年开展的小型兽类调查和研究中,通过形态学和分子鉴定的方法,证实在新疆发现的白尾高山䶄（Alticola albicauda True, 1894）是中国新纪录。该种尾全白色,末端有白色毛束;身体背部淡红褐色,腹部纯白。在基于Cyt b构建的系统树中和GenBank中的白尾高山䶄聚在一起,并与银色高山䶄（Alticola argentatus Severtzov,1879）形成姊妹群,两者间遗传距离为5%;在西藏发现小毛足鼠（Phodopus roborovskii Satunin,1902）,其特征和我国其他区域分布的小毛足鼠一致,两者之间Cyt b基因遗传距离（K2P）为0.6%,是西藏新纪录;在四川发现丽江绒鼠（Eothenomys fidelis Hinton, 1923）,牙齿特征,尾长和体长之比和地模标本基本一致,但个体较小,在基于Cyt b构建的系统发育树显示,四川标本为独立分支,表明形态和分子上均存在一定的分化,但和地模标本的遗传 距离只有1.1%,应为同一种,为四川省新纪录;在湖北发现循化鼠兔（Ochotona xunhuaensis Sou and Feng, 1984）,有异耳屏,头骨较扁平,符合循化鼠兔的鉴定特征,与模式产地的循化鼠兔Cyt b基因的遗传距离为1.9%,为湖北新纪录。     

转昆虫抗冻蛋白基因增强甘薯抗冻能力

为明确昆虫抗冻蛋白基因转入甘薯(Ipomoea batatas)后是否能提升其抗冻能力,进而为培育甘薯抗冻育种材料奠定基础,将黄粉虫(Tenebrio molitor)抗冻蛋白基因TmAFP导入植物基因表达质粒,经农杆菌介导的遗传转化获得抗冻甘薯新材料。以甘薯品种Huachano为受体材料建立甘薯植株高效再生体系,并采用不同成分的体细胞胚成熟培养基培养胚性悬浮细胞。胚性愈伤组织对除草剂的敏感性测试结果表明,转基因阳性植株筛选的最适培养基为MS+0.2 mg·L–12,4-D+0.8 mg·L^–1 GAP+100 mg·L^–1 Carb。将表达质粒分别转化Huachano后共获得7个胚性愈伤团并最终获得42株再生抗性植株,其中转pSUIBEV3-AFP有23个株系,转pCAMBIA-AFP有19个株系,经PCR、Southern杂交和RT-PCR检测后证实TmAFP基因已整合至甘薯基因组中并获得表达。将转基因甘薯及对照植株在–1℃下处理15小时后转移至室温,结果表明,转基因甘薯植株的抗冻能力显著提升。     

长期不同施氮水平对草原植物群落结构的影响

为探讨施氮对贝加尔针茅草原植物群落结构的影响,该研究于内蒙古贝加尔针茅草原设置不同施氮水平0(N0)、15(N15)、30(N30)、50(N50)、100(N100)、150(N150)、200(N200)和300(N300)kg·hm-2·a-1,研究连续施氮9年后贝加尔针茅草原群落物种组成、重要值、多样性及生物量等指标对不同施氮水平的响应。结果表明:(1)长期施氮导致植物群落物种组成发生了明显的变化,在高浓度氮素添加量下群落物种数最低,但可显著提高优势种在群落中的重要值(P<0.05)。(2)长期施氮使贝加尔针茅草原植物多样性指数不同程度地降低,使优势度指数增加,其中N300添加水平效果最为明显(P<0.05)。(3)长期施氮使草原植被生产力(地上、地下生物量)整体呈先上升后下降的趋势,地上生物量在N100水平时出现峰值,地下生物量在N50水平时出现最大值(P<0.05),且根系分布具有明显的表聚特征(0~10 cm)。(4)RDA分析表明,寸草苔和狭叶柴胡地上生物量与土壤pH呈显著正相关关系(P<0.05);展枝唐松草和二裂委陵菜地上生物量与土壤有机质含量呈显著正相关关系(P<0.05)。研究认为,长期不同施氮水平均可改变贝加尔针茅草原群落物种组成,降低物种多样性,对植物群落结构有着明显的影响。     

土地利用变化对三峡库区重庆段植被净初级生产力的影响

研究土地利用变化对区域植被净初级生产力(Net Primary Productivity,NPP)的影响对于明确区域植被固碳能力与土地利用变化的关系,以及维持生态系统结构稳定具有重要意义。以三峡库区重庆段为例,基于2000—2015年MOD17A3数据和土地利用数据,分析研究区NPP时空分布特征并从景观生态学的角度探讨土地利用变化对区域植被NPP的影响。研究表明:(1)NPP年均值16年间波动不大,空间分布上从东到西逐渐减少;(2)研究期内林地面积增加,耕地和草地面积减小,而NPP总量从25.6 TgC增加到了28.5 TgC,其中耕地NPP约占总量的44%,林地次之(40%),草地最少(14%),2000—2005年、2005—2010年、2010—2015年土地利用变化对NPP变化的贡献率分别为26.49%、59.76%、17.27%;(3)区域生态景观指数中的香农多样性指数SHDI、斑块密度PD与NPP呈正相关,而聚合度AI与NPP呈负相关,景观格局类型和景观格局变化均影响区域植被NPP的增长。要提高区域植被NPP,需优化土地利用格局,增加景观异质性和斑块密度,重视培育幼龄林,并控制成熟林的数量。     

钾肥及与秸秆配施对紫色土作物产量和微生物群落结构的影响

基于紫色菜园土壤莴笋-白菜-甜玉米轮作4年12季连续定位施钾肥试验,研究不同种类钾肥及用量对重庆地区紫色菜园土上作物产量和土壤微生物群落结构的影响,为该地区作物生产确定合理的施钾技术提供科学依据。结果表明,在施用氮磷肥基础上,不同钾肥处理莴笋、白菜、甜玉米产量均显著提高;从3种作物4年平均产量和钾肥效益看,以单施适量化学钾(K_2)、单施适量秸秆钾(M_2)和秸秆还田配施少量化学钾(K_1+M_1)的施钾肥模式对白菜的增产效果好,增产28.05%—30.27%;M_2和K_1+M_1施钾肥模式对莴笋的增产效果较好,增产13.89%和13.81%;K_1+M_1施钾肥模式对甜玉米的增产效果最好,增产15.10%,表明秸秆还田配施少量化学钾(K_1+M_1)模式在供试3种作物生产中具有很好的应用前景。不同施钾处理对土壤微生物群落结构及丰度均会产生一定影响,以秸秆还田配施少量化学钾肥(K_1+M_1)对提高土壤细菌、真菌、革兰氏阳性菌的作用较好,并显著增加土壤微生物总PLFA含量,缓解对土壤微生物生存环境的胁迫,说明K_1+M_1能为土壤微生物的生长繁育创造有利环境。莴笋、白菜、甜玉米3种作物4年平均产量与土壤细菌、真菌、革兰氏阳性菌和革兰氏阴性菌数量间存在显著相关性(P0.05),而不同钾肥处理对土壤微生物特征具有一定影响,说明施钾肥可能会调节土壤微生物特征,从而促进作物增产。