紫貂秋季生境选择的初步研究

采用无线电跟踪技术和全球定位系统（ＧＰＳ）对大兴安岭地区紫貂（Ｍａｒｔｅｓ ｚｉｂｅｌｌｉｎａ）秋季的生境选择进行研究。秋季紫貂对优势树种（以落叶松为主,７２％）、中下坡位（９０％）、小树密度（Ｐ＝０．０００４）、大树密度（Ｐ＝０００１）、大树胸径（Ｐ＝０．０００１）、倒木长度（Ｐ＝０．０００６）及密度（Ｐ＝０．０００１）都有一定的选择性,对坡向,灌丛盖度的选择性不明显,对中等盖度的林地有一定的选     

大兴安岭地区紫貂冬季生境选择的研究

１９９１～１９９３年在大兴安岭的呼中和图强区,采用雪地足迹跟踪法研究了紫貂（Ｍａｒｔｅｓｚｉ－ｂｅｌｉｎａ）冬季对取食和休息生境的选择特点,结果表明紫貂喜好植被演替晚期的林型,具体特点如下：（１）喜好中等到高等树冠盖度的乔木林地（Ｐ＝０．０００１）和混合型林地（Ｐ＝０．０２）,回避单一树种优势林地和空地。（２）对灌木盖度无选择性（Ｐ＝０．０９）,但喜好混合型灌木林地（Ｐ＝０．０３）。（３）取食时喜好下坡位及岸边,休息时选择上坡位（Ｐ＝０．００９）,且倒木、大胸径树和树根较多的生境,不选择坡向（Ｐ＝０．３９）。（４）对大树密度（Ｐ＝０．０００１）、落叶松基区面积（Ｐ＝０．００５）、大树胸径（Ｐ＝０．０００１）、落叶松胸径（Ｐ＝０．００１４）、倒木全长（Ｐ＝０．０００６）、倒木直径（Ｐ＝０．００１４）及倒木覆盖面积（Ｐ＝０．０００１）都有明显的正选择性,且休息对生境的选择强于取食。对小树密度取食时喜好中等密度（１．２１～１．８２棵／ｍ２）林地,而休息时回避高密度区（１．８２～３．０３棵／ｍ２）。根据上述结果建议在择伐过程中应当保留植被演替晚期的林型和胸径在４０ｃｍ左右的大树。     

紫貂春季和夏季生境选择的初步研究

１９９４～１９９６年,在大兴安岭满归林业局北岸林场的阿巴河流域原始林中,采用无线电跟踪技术和全球定位系统（ＧＰＳ）对紫貂春季和夏季的生境选择进行了研究。结果表明：１）紫貂对盖度为６％～７５％的林地选择性强,而对５％以下和７６％以上地区选择性较弱;栖息地优势树种为兴安落叶松;（２）主要喜欢中、下坡位;（３）对小树密度、大树密度、乔木胸径（ｄｉａｍｅｔｅｒ ｏｆ ｂｒｅａｓｔ ｈｅｉｇｈｔ,ＤＢＨ）、     

紫貂冬季食性的分析

１９９１至１９９８年的三个冬季,在大兴安岭地区共收集紫貂粪样２２３个．食性分析结果表明,紫貂冬季食物主要为小型哺乳类（５４．１％）、植物浆果和种子（３２．４％）、鸟类（１２．５％）和昆虫（１．０％）．在紫貂选择的７种小型哺乳类中,主要以棕背（２７．３％）和红背（１９．２％）为食,其次为雪兔和冬眠的花鼠。对于鸟类,紫貂主要捕食花尾榛鸡（８．１％）,松鸦（０．７％）,大山雀（０．５％）和黑啄本鸟等。有２．２％的粪样中含有小型鸟的卵壳、紫貂的植物性食物主要为越桔浆果（２０．８％）和偃松种籽（８．８％）。昆虫中只有蚂蚁在紫貂食性中出现（１．０％）．紫貂冬季食物构成没有年度间差异（Ｐ＞０．０５）。通过捕食迹,我们还发现紫貂捕食黑嘴松鸡。虽然红背的捕获率（７９．４％）高于棕背（２．９％）,但食性分析结果却相反,说明紫貂更喜欢捕捉身体较大的鼠类。有较强气味的中虽有一定的数量,但在紫貂冬季食物中未出现过。     

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。     

秦岭周至自然保护区斑羚夏冬季生境选择利用

2014年2月、2014年12月—2015年1月和2015年6—7月,在陕西省周至自然保护区,采用样带法对斑羚冬季和夏季生境选择进行研究。结果表明,斑羚夏季对14种生境因子有选择性,而在冬季斑羚对16种生境因子有选择性。夏冬季斑羚对植被类型、坡位、海拔、坡度、郁闭度、乔木大小、乔木距离、灌木密度、灌木距离、灌木盖度、草本盖度、草本种类、距隐蔽物距离和距人为干扰距离的选择存在显著差异。逻辑斯蒂回归分析表明,坡向、坡位、乔木大小、乔木距离、灌木大小、隐蔽级、距隐蔽物距离、距人为干扰距离是斑羚夏季生境选择的主导因子。坡向、坡位、郁闭度、乔木距离、灌木大小、灌木距离、草本种类、隐蔽级、距水源距离是斑羚冬季生境选择的主导因子。     

甘肃兴隆山保护区野生马麝的冬季卧息地生境特征

生境是野生动物的栖息基底,卧息地是野生动物重要的功能性生境。为深入了解野生马麝（Moschus chrysogaster）冬季卧息地生境的特征及选择利用,于2021年12月至2022年1月对甘肃兴隆山国家级自然保护区的野生马麝的功能性生境开展了基于生境取样的研究。通过样线调查法获取马麝卧息痕迹位点,采用主成分分析和资源选择函数法进行其卧息生境选择的研究。结果表明,野生马麝冬季卧息地生境的海拔较低[（2 488.5±26.6）m]、灌木较高[（1.3±0.3）m]、灌木盖度（31.08%±3.14%）和地表植被盖度（38.36%±3.27%）较大、倒木较多[（0.5±0.1）个]且积雪较浅[（1.0±0.3）cm];马麝冬季卧息地多选择位于南坡的下坡位灌丛生境,而且距水源较近、隐蔽度较好。主成分分析表明,乔木因子、食物因子、安全因子和地形因子的累计贡献率达67%;马麝的卧息生境资源选择函数为：Logit(x)=﹣4.967+0.001×海拔﹣0.02×坡度+0.03×乔木郁闭度+0.104×乔木高度+0.17×灌木盖度﹣0.466×雪被深度﹣1.015×坡向,模型预测正确率为91.1%。...     

在高CO2浓度下四种亚热带幼树光合作用对水分胁迫的响应

在较高CO2浓度（700μl/L）下,随着光强（PAR）增高,严自高林林地植物罗伴的光合速率（Pn）增高,当叶片水热（Ψ）从－0.92kPa降低至－2.0kPa,Pn/PAR斜率从0.037降至0.017,即观量子产率（αA）降低54.0％;而来自林密度中等林地的九节和荷木,当叶片水热分别从－0.80kPa降到－2.00和-1.20kPa,αA分别降低22.2%和19.4%;来自开阔地的桃金娘叶片水势降低时,αA亦见明显降低。当叶片水势降低1kPa,罗伞叶片的光能转换效率（δ）降低0.10电子／量子或39.2%,九节和荷木,以及桃金娘相应降低0.033至0.05电子／量子。来自高林密度林地罗伞叶片水热从-0.92kPa降低至-2.00kPa,最大羧化速率（Vcmax）降低24.3%,来自林密度中等林地的九节叶片水热低1kPa,Vcmax降低7.08μmol/m^2s,荷木和疏林桃金娘则有明显高的Vcmax。叶片水势降低,Vcmax亦受明显抑制（P＜0.01）。结果表明,来自林或等林地的荷木和来自开阔林地的桃金娘有着高的Rubisco激活特性,叶片水势降低明显影响Rubisco的激活特性,来自较稀疏林地的荷木和桃金娘有较高电子传递速率（J）,叶片水势降低1kPa,J分别降低52.5和58.1μmol m^2/s,而来自高林密度林地的罗伞,J降低仅为8.9-9.0μmol m^2/s。表明阳生树种的J对水分胁迫响应敏感。研究结果表明,阳生树种有较高的Vcmax,J,δ和Г^*。叶片水势降低引起光合参数不同程度降低,但阳生树种仍维持国产高的光合参数值,这有利于阳生植物生物量的积累和保持种群的优势,从而有利于亚热带常绿阔叶林是生植物群落向中生性和耐荫顶极植物群落的演替。     

大兴安岭原麝冬季的生境选择

2005年3～4月和2006年3月,在黑龙江省大兴安岭呼中自然保护区,采用机械布点法随机设置样线,对原麝(Moschus moschiferus)冬季生境选择进行了研究。对海拔、乔木密度、雪深、隐蔽度、食物丰富度、坡度和倒木数量进行2个独立样本的Mann-Whitey U检验,找出生境利用样方与任意样方的生态因子的差异。U检验的结果表明,原麝冬季喜欢活动在相对海拔高、乔木密度小、雪层浅、隐蔽度高、坡度陡且喜食食物丰富的区域;对植被类型、坡位、坡向、距水源距离、距人为干扰距离、动物干扰和碎石坡7个名词性变量采用卡方(Chi-square)统计进行显著性检验,卡方检验的结果表明:原麝冬季偏好远离人为干扰、接近碎石坡、阳坡和其他动物干扰较少的针阔混交林中;对以上14个生态因子进行主成分分析,结果表明,前6个特征值的累计贡献率达到72·318%,可以较好地反映原麝生境特征,根据主成分分析结果,将原麝冬季生境选择影响因子分别命名为空间因子(海拔、坡度、距碎石坡距离)、干扰因子(距人为干扰距离、距水源距离)、坡向因子(坡向、乔木密度)、坡位因子(坡位、动物干扰)、食物因子(食物丰富度、隐蔽度)和倒木因子(倒木数量)。     

秦岭大熊猫冬春季节对巴山木竹竹林生长指标的选择

2004~2005年冬季的12月、1月和春季的4月、5月,在秦岭山系南坡佛坪自然保护区内就大熊猫对构成其主要栖息地和食物来源的巴山木竹竹林的选择进行研究后的结果表明:在冬季,大熊猫栖息地多为幼竹与死竹比例基本持平、密度稳定的巴山木竹竹林,主要取食老竹;在春季,大熊猫更偏好选择竹子密度和盖度略低、竹子粗壮高大、幼竹与竹笋比例高的竹林活动,主要取食幼竹。大熊猫春季栖息地幼竹比例通常高过死竹比例,竹林密度处于增长期。竹林进入发笋期后,稀疏、高大的竹林下的粗大竹笋成为大熊猫的主要食物来源。     

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.