四川雉鹑的冬季夜栖地选择

四川雉鹑(Tetraophasis szechenyii)是中国特有物种,国家Ⅰ级重点保护野生动物,对其冬季夜栖地选择的了解,有助于理解物种的生存策略,为物种保护提供参考。利用徒步跟踪和无线电遥测的方法,我们于2006年9月到2007年4月在四川省雅江县帕姆岭进行了野外研究。采用卡方检验、配对样本t检验和二元逻辑斯缔回归等方法对数据进行分析。结果发现:(1)四川雉鹑利用鳞皮冷杉(Abies squamata)和大果红杉(Larix potaninii var.macrocarpa)两种树夜栖,卡方检验分析发现四川雉鹑对这两树种没有明显的选择偏好(χ2=0.745,df=1,P=0.388);(2)夜栖树的胸径为(25.8±1.3)cm,夜栖枝条离地高度为(6.3±0.3)m,直径为(3.3±0.1)cm;(3)与对照样地相比,夜栖地生境一般靠近林缘,乔木的平均胸径大、林下盖度小、倒木数量多,夜栖树胸径大、最近乔木胸径大和最近乔木距离远;(4)逻辑斯缔回归分析表明:夜栖树第一枝距地面高为冬季四川雉鹑夜栖地选择的关键因子;倒木数量、平均乔木胸径、最近林缘距离为次关键因子,该模型对夜栖地的预测正确率为80.9%。冬季四川雉鹑选择夜栖地是安全、能量和地点转移三个因素综合作用的结果,在不同的环境下,同一物种对环境会有不同的适应策略。     

再引入黑颈长尾雉夜栖行为与夜栖地选择

2003年4月～2005年3月,通过野外观察、无线电遥测和样方调查,对广西岑王老山自然保护区再引入黑颈长尾雉的夜柄行为和夜柄地进行了研究.共观察记录到10个夜栖地,黑颈长尾雉夜间主要在树上栖息,偶尔在地上柄息,在针叶林为独栖(1只/树),在阔叶林独柄或者2～3只/树.黑颈长尾雉夜柄地选择受到柄树的高度、大小,灌术、乔木、草本层的盖度,水源距离及栖枝高度等因素的影响.黑颈长尾雉夜栖地的栖树具有一定的高度(雌:4.96±1.39 m,雄:5.52±1.95 m)和胸围大小(雌:21.4±8.29 cm,雄:23.50±8.39 cm);乔木层(78.00%±8.23%)和灌木层(44.50%±29.67%)盖度较大,草本层盖度较低的环境作为夜栖地;与水源具有一定的距离(348.50±308.30)m;夜栖地的坡度(44.80.±14.73.)和栖枝的高度(2.40±0.74 m).     

陕西黄龙山林区褐马鸡春季夜栖地选择

2006年4～6月,在陕西黄龙山林区,对褐马鸡(Crossoptilon mantchuricum)春季夜栖地的选择进行了研究.共记录到22个夜栖地,以夜栖树为中心做一个10 m×10 m样方,测定夜栖地海拔、坡向、坡度、坡位、地貌特征、夜栖树高度和胸径、乔木层盖度、乔木的数量、灌木层盖度、草本盖度、水源距离、人为干扰距离、林缘距离、栖枝高度和栖位上盖度等参数;通过9条样带测定54个随机样方,除栖枝高度和栖位上盖度外,指标相同.结果表明,褐马鸡春季夜栖地多偏向以坡度较大、山坡和山脊、接近水源、远离林边、人为干扰距离较远、乔木盖度和密度较大、栖树胸径较大、灌木层盖度和草本层盖度较小为主要特征的地方.主成分分析表明,前5个特征值的累积贡献率达到72.746%,可以较好地反映褐马鸡春季夜栖地生境特征.根据载荷系数绝对值大小,将褐马鸡春季夜栖地生境选择影响因子分别命名为地形和林下植被因子、气象因子、稳定性因子和水因子.影响褐马鸡夜栖地选择的关键因素是安全、舒适和栖息地转换的方便程度.     

海南原鸡繁殖期夜栖地的选择

原鸡Gallus gallus在繁殖期的日常活动趋向于以夜栖地为中心,因此夜栖地的研究对原鸡的繁殖和保育具有重要意义.2008年2～5月在海南大田自然保护区,采用野外观察和样方调查相结合的方法,对原鸡的夜栖地利用进行了研究,共记录到15个夜栖地.结果表明: 1) 原鸡在繁殖期多结成2～6只(3.3±1.5, n=13)的繁殖群,在同一棵树或邻近几棵树上集群夜栖; 2) 落叶季雨林和灌丛草地是原鸡繁殖期夜栖的主要植被类型; 3)原鸡多以小刺竹Bambusa bambos作为夜栖树,占53.3%,其次是厚皮树Lannea coromandelica,占20.0%; 4)原鸡倾向于选择灌木生长茂密、地面草本稀疏的生境作为夜栖地,并栖息在胸径均值为8.4 cm±3.5 cm的乔木或灌木的枝条上,栖枝均高为4.4 m±0.8 m; 5)主成分分析表明,影响原鸡夜栖地选择的主要因子依次为:栖树高、栖枝高度、栖树胸径、栖枝层盖度、草本层盖度、栖枝下方盖度和栖枝上方盖度.据此分析认为:繁殖期原鸡警惕性高,夜栖地多选择易于隐蔽和转移的生境.     

广西黑颈长尾雉对夜宿地的选择

2003年12月、2004年5月和12月、2005年4月,通过野外调查及设置样方的方法对广西金钟山鸟类保护区黑颈长尾雉的夜宿地选择进行了研究。共记录到12个夜宿地,以夜宿树为中心做一个10m×10m和5个1m×1m的样方,记录夜宿树特征(种类、胸径、栖枝高度、栖枝直径、栖枝上方盖度),测量每个样方的11个生境因子(海拔、林型、坡向、坡度、乔木层盖度、灌木层盖度、草本层盖度、距水源距离、距林缘距离、距道路距离和乔木密度);并随机设10个对照点,测量相同的生境因子。结果表明,黑颈长尾雉夜宿地主要位于阔叶林中,一般,夜间在乔木上休息,一树栖息一只,也有2—3只同宿一树。黑颈长尾雉选择有一定坡度、林下灌木和草本较少以及在森林内部远离林缘并且乔木密度较大的地方作为夜宿地,其夜栖树主要为生境内的中等大小的阔叶树,栖枝直径约为2·5—4cm,栖处高度为2—5m,黑颈长尾雉夜宿地的选择与距水源距离的远近无关。影响黑颈长尾雉夜宿地选择的因素依次为:位置及林下植被、栖枝、天气。影响黑颈长尾雉夜宿地选择的最终原因可能是安全、舒适和栖息地转换的方便程度。     

广西黑颈长尾雉对夜宿地的选择

2003年12月、2004年5月和12月、2005年4月，通过野外调查及设置样方的方法对广西金钟山鸟类保护区黑颈长尾雉的夜宿地选择进行了研究。共记录到12个夜宿地，以夜宿树为中心做一个10 m×10 m和5个1 m×1 m的样方,记录夜宿树特征(种类、胸径、栖枝高度、栖枝直径、栖枝上方盖度)，测量每个样方的11个生境因子(海拔、林型、坡向、坡度、乔木层盖度、灌木层盖度、草本层盖度、距水源距离、距林缘距离、距道路距离和乔木密度)；并随机设10个对照点，测量相同的生境因子。结果表明，黑颈长尾雉夜宿地主要位于阔叶林中，一般，夜间在乔木上休息，一树栖息一只，也有2—3只同宿一树。黑颈长尾雉选择有一定坡度、林下灌木和草本较少以及在森林内部远离林缘并且乔木密度较大的地方作为夜宿地，其夜栖树主要为生境内的中等大小的阔叶树，栖枝直径约为2.5—4 cm，栖处高度为2—5 m，黑颈长尾雉夜宿地的选择与距水源距离的远近无关。影响黑颈长尾雉夜宿地选择的因素依次为：位置及林下植被、栖枝、天气。影响黑颈长尾雉夜宿地选择的最终原因可能是安全、舒适和栖息地转换的方便程度。     

应用资源选择函数对褐马鸡冬季夜栖地选择的研究

2006年11月至2007年1月,在陕西黄龙山腹地的北寺山林区,对褐马鸡Crossoptilon mantchuricum冬季夜栖地的选择进行了研究。共记录到34个夜宿地,以夜宿树为中心各做一个10m×10m样方,测定夜栖地海拔、坡向、坡度、坡位、夜栖树高度和胸径、乔木层盖度、乔木数量、灌木层盖度、草本盖度、离最近水源距离、离林间道路的距离、离最近林缘的距离、离最近居民点距离等参数;对照样方采用随机抽样法,在研究区域内设置同样数目的对照样方,测定同样指标。结果表明,褐马鸡冬季夜栖地选择的资源选择函数为:logit(p)=-11.537 2.245×坡度 3.452×乔木盖度 2.001×乔木数量-2.903×与最近居民点的距离。根据拟合出的资源选择函数,褐马鸡冬季对夜栖地的选择概率为P=elogit(p)/(1 elogit(p)),模型的正确预测率可达到93.8%。模型表明,冬季褐马鸡夜栖地的选择概率与坡度、乔木盖度和栖树数量呈正相关,与距居民点距离呈负相关。     

四川雉鹑育雏早期雌体与幼体夜栖地的选择

开展鸟类幼体夜栖生境的研究,对于确定物种的生存策略并实施生境保护具有重要的参考价值。四川雉鹑Tetraophasis szechenyii是我国Ⅰ级重点保护物种。利用无线电遥测和直接跟踪的方法,对育雏早期(幼体孵化后大约2周内)雌体与幼体的夜栖生境进行研究。研究发现,在幼体孵化后1周内,雌体与幼体夜栖于地上(n=3);在第2周,它们开始上树夜栖(n=12)。当树栖时,偏好选择鳞皮冷杉-大果红杉林,并使用乔木盖度和坡度较大的地方。与育雏后期的正常夜栖生境相比,本阶段雌体与幼体的夜栖地的乔木盖度更大,但夜栖树胸径较小且靠近道路。基于本研究,建议在生境保护方面应该维持一定区域的乔木盖度,并适当注意保留一些中小型乔木。     

白腹锦鸡(Chrysolophus amherstiae)的夜栖地选择

2005年4月～2006年9月,结合无线电遥测技术,采用系统搜索法和繁殖期跟踪法对四川石棉县栗子坪自然保护区白腹锦鸡的夜栖地选择进行了研究。共发现24个夜栖地。以夜栖树为中心做r=7.5m大样方,随机在其中做4个1m×1m和4个0.5m×0.5m小样方,测量乔木、灌木和草本植物的各项参数;做128个非活动区对照样方和258个日栖地样方,分别随机选取等量样方与夜栖地样方相比较。结果表明:白腹锦鸡夜栖地多在针阔混交林和针叶林中,栖树以针叶树为主,繁殖期内成对个体同树共栖的栖位距离较近,栖枝雄高雌低。影响白腹锦鸡夜栖地选择的主要因素依次为:地形、栖树、隐蔽条件和遮蔽特征。与对照样方相比,白腹锦鸡夜栖地选择较矮而疏的乔木和少量倒木的环境;与日栖地样方相比,选择较矮、疏和较低盖度灌木草本植物的环境,有一定的空间分离。     

四川老君山地区红腹角雉的夜栖行为和夜栖地选择

2005年4–8月和2006年3–8月, 采用无线电遥测、野外追踪及观察等方法对四川老君山自然保护区红腹角雉(Tragopan temminckii)的夜栖行为和夜栖地选择进行了研究, 共记录树栖19例和地栖2例, 未见2只以上同栖1树。栖枝平均直径4.6 cm, 平均高度6.8 m。夜栖个体天黑前0.5–1 h上树, 黎明后0.5 h左右下树。夜栖时间受季节和天气影响: 晴好天气下, 夏季的平均夜栖时间(615.7 ± 15.7 min)较春季和秋季(658.3 ± 5.9 min)短; 夏季中, 晴好天气夜栖平均时间比不良天气(阴霾、大雾、雨天)(661.5 ± 6.8 min)短。夜栖树隶属于2科(壳斗科、木兰科)6种。研究区内红腹角雉最主要的夜栖地是常绿落叶阔叶混交林—竹灌混交林。在夜栖树周围选取样方并测量了反映夜栖地特征的22个变量, 同时分析19个对照样方以进行比较。方差分析和Mann-Whitney U检验显示, 红腹角雉偏好竹灌丛、乔木层盖度较高的陡峭上坡位山地夜栖。主成分分析显示, 植被因子和栖枝方向因子贡献率最大。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.