贺兰山区马鹿对冬季生境的选择性

2003年11—12月,在贺兰山采用样带法对马鹿阿拉善亚种的生境选择性做了研究。在选定的25条样带上一共测定了87个利用样方以及50个任意样方的14种生态因子(植被类型、优势乔木、坡向、坡位、食物丰富度、乔木密度、灌木密度、坡度、海拔高度、雪深、水源距离、人为干扰距离、裸岩距离和隐蔽级)。结果表明,马鹿对4种生态因子有选择性：①植被类型：偏好利用山地草原带和山地针叶林带,避免选择亚高山灌丛和草甸带;②优势乔木：偏好利用混合型的生境,避免选择杜松、油松和无树的生境;③坡向：偏好位于阳坡的生境,避免利用阴坡;④坡位：偏好位于下坡位的生境,避免选择上坡位和中坡位。对利用样方和任意样方进行比较,发现马鹿的利用样方以灌木密度高、食物丰富、坡度小、接近水源、雪覆盖浅、远离裸岩和人为干扰为主要特征。对各种生态因子的主成分分析表明前6个主成分的累积贡献率已经达到了84．89％,可以较好地反映马鹿的生境特征。第1主成分反映出马鹿在选择生态因子方面与植被类型、乔木密度、灌木密度、坡向、坡度、距水源距离、雪深、海拔高度正相关。     

陕西黄龙山林区褐马鸡春季觅食地选择

2006年4～5月,在陕西黄龙山林区采用样带法对褐马鸡(Crossoptilon mantchuricum)春季觅食地选择进行了研究.共测定了9条样带上的54个随机样方和54个栖息地利用样方的20个生态因子.结果表明,褐马鸡春季觅食期间偏好利用针阔混交林,避免针叶林和阔叶林;偏向于下坡位,避免上坡位和中坡位;偏向于中等坡度的山坡(10～20°),避免坡度较大和较小的山坡;对坡向没有明显的选择性.对利用样方和随机样方进行比较,发现利用样方具有海拔较低、与林间小路和水源较近、乔木种类较少、乔木密度较小、乔木最大胸径较大、乔木最大高度较高、灌木种类较少、灌木密度较小、食物丰富度较大、灌木层植物盖度较小、乔木层植物盖度较大、隐蔽级较小等特征.逐步判别分析表明,乔木密度、与水源距离、灌木密度、灌木种类、乔木最大高度、海拔具有重要作用,由这6个变量构成的方程在对繁殖季节觅食地利用样方和对照样方进行区分时,正确判别率可以达到97.22%.褐马鸡春季觅食地选择主要与食物条件、隐蔽条件和水源有关.     

贺兰山岩羊（Pseudois nayaur）夏季取食和卧息生境选择

采用直接观察法和痕迹检验法对贺兰山岩羊夏季取食和卧息生境选择进行研究.结果表明,夏季岩羊偏好的取食地位于海拔高度1 600～2 000 m的山地疏林草原带,地形为平滑起伏的坡、明显断裂的坡和悬崖,以灰榆和山杨为优势乔木或无树,乔木矮小稀疏且距离远,接近低矮但密度较大的灌木,食物较多,位于<30°和>35°半阴半阳坡的下坡位,接近水源,人为干扰距离500～1 000 m,距裸岩2～5 m,隐蔽级25%～75%;夏季岩羊偏好的卧息地具有位于海拔高度1 600～2 000 m和>3 000 m的山地疏林草原带及亚高山灌丛和草甸带,地形为明显断裂的坡和悬崖,以灰榆和山杨为优势乔木或无树,乔木和灌木均矮小稀疏且距离较远,食物较少,位于>35°阴坡的上坡位,接近水源,人为干扰距离远,接近裸岩,隐蔽程度低.岩羊的取食和卧息生境在乔木高度和距水源距离上差异不显著(P > 0.05),而其余生态因子均有显著差异(P < 0.05).与取食生境相比,岩羊选择的卧息生境具有乔木稀疏且距离较远、灌木较少、低矮且距离较远、食物丰富度低、坡度大、远离人为干扰、接近裸岩和隐蔽程度低的特征.逐步判别分析表明,食物丰富度、灌木高度、距水源距离、隐蔽级、灌木密度、灌木距离、乔木高度和乔木距离8个生态因子可以区分取食样方与任意样方,正确判别率为85.8%;而区分卧息样方与任意样方时,距水源距离、灌木高度、距裸岩距离、人为干扰距离、食物丰富度、灌木密度和灌木距离共7个生态因子发挥作用,正确判别率为89.1%.     

贺兰山马麝秋季生境选择

为了更好地保护和管理贺兰山的马麝Moschus sifanicus种群,2014—2016年秋季,采用样线法和样方法对贺兰山马麝的秋季生境选择进行研究。共记录利用样方181个,对照样方75个,测定了17种生态因子。对非数值型生态因子采用拟合优度卡方检验进行分析,使用Bonferroni不等式分析马麝对其的偏好性,然后通过非参数检验Mann-Whitney U检验对利用样方与对照样方中的13种数值型生态因子进行比较,最后对数值型生态因子中差异显著的8个生态因子采用逐步判别分析。结果表明:(1)马麝偏好以青海云杉Picea crassifolia为优势乔木的山地针叶林阴坡的中坡位。(2)马麝趋向于海拔高、乔木密度高、乔木距离近、灌木密度低、人为干扰距离远、距裸岩距离远、隐蔽级高的栖息地类型。(3)差异性显著的生态因子按照贡献值大小依次为:隐蔽级、距裸岩距离、海拔、人为干扰距离、灌木密度、乔木高度、乔木距离和乔木密度,隐蔽级是影响马麝秋季生境选择最重要的生态因子。     

陕西凤县春季林麝生境的初步分析

2006年4～5月,在陕西凤县共设置41个20 m×20 m的样方和14个生态因子,并以此为基础数据,分析结果表明,林麝春季喜欢选择在海拔1700～2100 m、灌木盖度、竹子密度、倒木密度、树桩密度、动物干扰程度均较低、坡度≥ 40°、半阴半阳坡、远离人类生产活动、有土质覆盖的生境.其他生态因子郁闭度、隐蔽级、乔木密度、灌木密度均以适中为准.因子分析的结果表明,前7个公共因子的累计贡献率达到76.63%,基本上反映了林麝春季栖息地的特征.在前7个公共因子中,占有较高信息载荷系数的变量依次为灌木盖度、树桩密度、乔木密度、活动基底、隐蔽级、人为干扰、竹子密度.     

贺兰山马鹿冬季取食和卧息生境选择

2007 年12 月至2008 年1 月,在贺兰山地区,利用痕迹检验法和直接观察法对马鹿阿拉善亚种的冬季取食和卧息生境选择进行研究。通过在选定的15 条沟段里进行调查,共测定了72 个取食利用样方,59 个卧息利用样方和131 个对照样方的18 种生态因子。结果表明,马鹿在冬季偏好的取食地为平滑起伏坡,以酸枣、柳为优势乔木、混合型树林或空地,乔木高大稀疏、间距较远,灌木密度大,草本盖度较高,位于< 15°的半阴半阳坡的下坡位,距裸岩远,隐蔽度高;偏好的卧息地在山地疏林草原带的平滑起伏坡上,以酸枣、柳为优势乔木、混合型树林或空地,乔木高大稀疏,灌木矮小、稀疏且距离较远,草本盖度较高,位于< 15°阳坡的下坡位,远离裸岩,隐蔽程度高。马鹿冬季的取食和卧息生境在草本盖度和隐蔽度上差异极显著。相对于卧息生境,马鹿冬季的取食生境对草本盖度和隐蔽度要求更低一些。马鹿冬季取食地的资源选择函数为1.155 - 0.149 × 乔木高度- 0.066 × 草本盖度+ 0.190 × 坡度,模型的正确判别率为86.8% ;马鹿冬季卧息地的资源选择函数为- 30.936
+ 0.494 × 乔木高度+ 0.257 × 坡度-0.002 × 海拔高度+ 0.387 × 隐蔽度,模型的正确判别率为95.8% 。食物、隐蔽条件以及贺兰山的独特地形特征是影响马鹿冬季取食和卧息生境选择的主要因素。     

贺兰山岩羊冬季对卧息地的选择

2003 年11～12月, 在贺兰山采用样带法对岩羊冬季卧息地的选择性进行了研究。共观察到94 个岩羊的卧息地, 结果表明岩羊对优势乔木的利用有选择性( x² = 17.01 , df = 5 , P < 0.05) , 偏好利用灰榆占优势的卧息地, 避免选择油松和青海云杉占优势的卧息地; 对坡向选择性利用( x²= 30.69, df =2, P < 0.05) , 偏好位于阳坡的卧息地, 避免利用阴坡; 对植被类型、坡位和风向的利用无选择性。对卧息地样方与在样带中随机设置的样方进行比较, 发现卧息地具有乔木密度低、食物丰富度低、隐蔽程度高、接近水源、接近裸岩、风速低和雪覆盖浅等特征。贺兰山的岩羊经常选择岩洞作为卧息地, 占总卧息地的62.77 %。对59 个岩洞和35 个非岩洞卧息地进行比较, 表明岩洞卧息地的坡度大、隐蔽程度高、风速低、保温性好、食物丰富度低和无雪覆盖。岩羊通常选择较宽的、深度和高度适中的岩洞作为卧息地。对各种生境因子的主成分分析表明前7 个特征值的累积贡献率已经达到了80.09%, 可以较好地反映岩羊卧息地的生境特征, 第1 主成分中隐蔽级、风向、风速、距裸岩距离和雪深具有重要作用, 其余6 个主成分中优势乔木、坡向、坡位和坡度也很重要。     

四川铁布梅花鹿自然保护区梅花鹿夏季栖息地选择

四川梅花鹿Cervus nippon sichuanicus为国家Ⅰ级重点保护动物,四川铁布梅花鹿自然保护区分布有我国现存最大的梅花鹿野生种群。2011年6-9月,采用样方法对保护区梅花鹿夏季栖息地选择进行了调查,共布设109个样方(利用样方61个,对照样方48个),测量并比较了海拔、坡度等20个生境因子。结果显示,梅花鹿偏好利用的植被类型为灌丛、草甸、针叶林,同时选择隐蔽度较高的生境;此外,距水源距离、灌木高度、灌木盖度、灌木密度、草本高度和草本盖度6个连续变量在利用样方和对照样方之间差异有统计学意义(F<0.05或U<0.05)。回归模型分析结果表明,梅花鹿夏季偏好选择草本盖度大、靠近水源和林缘的生境,回避远离水源和林缘的生境。     

黄泥河自然保护区狍冬季栖息地选择

2009年12月—2010年1月,在黄泥河自然保护区采用样线法对狍冬季栖息地选择进行了研究。共设置了47条样线,调查了109个狍利用样方和109个对照样方,测定了海拔、坡度、坡向、坡位、隐蔽级、郁闭度、食物丰富度、灌丛盖度、树胸径、人为干扰距离、林型、裸岩、雪深、倒木和针叶树15类栖息地因子。Baileys法和Mann-WhiteyU检验表明:在黄泥河自然保护区冬季,狍喜欢在坡度平缓、平均海拔602m,位于阳坡或半阴半阳坡的中坡位上雪被较浅,食物丰富度、灌丛盖度和隐蔽级都较高的针阔混交林生境中活动,对倒木因子表现出明显的选择性,避开选择阴坡、裸岩和针叶林生境。在主成分分析中,前5个主成分中的累积贡献率达到88.6%,第一主成分贡献率为30.8%,主要反映利用样方的林型、海拔和隐蔽级的影响,第二主成分贡献率为26.5%,主要反映利用样方的食物丰富度和灌丛盖度影响。     

大兴安岭原麝夏季的生境选择

2005年7月和2006年8月,在黑龙江呼中国家级自然保护区,采用机械布点法设置样线,对原麝夏季生境选择进行了研究.Mann-Whitey U检验表明,原麝夏季喜欢活动在乔木密度小、郁闭度低、坡度较陡且隐蔽度高的生境中;卡方检验表明,原麝夏季偏好远离人为干扰的中上坡位、接近碎石坡和水源的阴坡或半阴半阳坡的针阔混交林中;主成分分析表明,前6个特征值的累计贡献率达72.28%,可较好地反映原麝生境特征,因而将原麝夏季生境选择影响因子分别命名为干扰因子、林型因子、坡度因子、水源因子、空间因子和郁闭度因子.     

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.