虾池常见微藻种群温度、盐度和氮、磷含量生态位

就温度、盐度、氮磷含量设计试验,对4种虾池常见微藻种群新月菱形藻、啮蚀隐藻、微绿球藻、蛋白核小球藻的生态位进行研究.结果显示：啮蚀隐藻在温度和盐度资源上的生态位宽度值最大,分别达0.980和0.988,新月菱形藻在氮、磷含量资源上的生态位宽度值最大,达0.990,蛋白核小球藻在各资源的生态位宽度值均最小,平均只有0.926;啮蚀隐藻与蛋白核小球藻在温度和盐度资源上的生态位重叠值最小,分别为0.809和0.702,啮蚀隐藻与新月菱形藻在氮、磷含量资源上的生态位重叠值最小,只有0.829,蛋白核小球藻与微绿球藻在温度、盐度和氮、磷含量资源上的生态位重叠值均最大,分别为0.986、0.974和0.989.表明在养殖水环境调控过程中,啮蚀隐藻适宜与新月菱形藻、微绿球藻或蛋白核小球藻共同培育,而蛋白核小球藻和微绿球藻对资源的竞争性明显,不适合同时引入同一池塘进行培育.     

五种淡水微藻的适宜培养温度和光照强度

从淡水中分离得到绿球藻(Chlorococcum sp.)SHOU-F3、纤维藻(Ankistrodesmus sp.)SHOU-F33、小球藻(Chlorella sp.)SHOU-F46、空星藻(Coelastrum sphaericum)SHOU-F10和栅藻(Scenedesmus sp.)SHOU-FX,分别在光照培养箱中研究了温度、光照强度对5种微藻增殖的影响,并分析了5种微藻的细胞组成。结果表明:绿球藻SHOU-F3、纤维藻SHOU-F33、小球藻SHOU-F46、空星藻SHOU-F10和栅藻SHOU-FX的最适生长温度分别为29.8、23.5、31.4、34.4和24.7℃;最适光照强度分别为16、119、42、82和106μmol·m-2·s-1;在适宜培养条件下,绿球藻SHOU-F3的色素、蛋白以及总糖的百分含量最高,纤维藻SHOU-F33的脂肪百分含量最高。     

苏州城市河道滞流水体浮游植物常见属生态位研究

采用Colwell公式、余世孝和Pianka公式计算了苏州城市河道滞流水体浮游植物常见属的生态位宽度、二维(TN,TP)生态位中心点、一维(NH3-N)生态位中心点及生态位重叠.结果表明:重污染河道中蓝纤维藻、十字藻、卵囊藻、栅藻、小环藻的生态位宽度值较大,色球藻和蓝隐藻的生态位宽度值较小;蓝纤维藻、十字藻、卵囊藻、栅藻、小环藻、隐藻和蓝隐藻占据二维(TN,TP)生态空间的中心,而色球藻、颤藻和直链藻占据生态空间边缘;色球藻和颤藻的生态位重叠值最小,蓝纤维藻和十字藻生态位重叠值最大.在苏州城市河道中,氮磷浓度偏高,氨氮含量较大的情况下,绿藻门的生态位宽度普遍较大,各属种与其它各门的生态重叠值也均较高,与蓝藻相比具有竞争优势.     

淀山湖浮游植物优势种生态位

运用改进的Levins公式和Petraitis指数测定了淀山湖浮游植物优势种的生态位宽度和生态位重叠,分析了生态位宽度、种间生态位重叠与优势种密度和优势度的相关性.结果表明： 不同时期各优势种的生态位宽度和生态位重叠不尽相同,各物种对环境因子的适应能力存在差异.根据不同季节的生态位宽度可以将淀山湖浮游植物优势种分为4类;尖尾蓝隐藻和小球藻的生态位较宽,数量较多,分布较广,能充分利用环境资源.水华暴发时期,蓝藻门各优势种与其他藻类之间的生态位重叠程度相对偏高;铜绿微囊藻的生态位变宽,而其他优势种的生态位宽度相对有所降低.各季节优势种的优势度与其生态位宽度呈显著相关,优势种密度与生态位重叠呈极显著相关.     

单生卵囊藻(Oocystis solitaria)和月牙藻(Selenastrumsp.)的培养条件及其细胞组成

从海滨的淡水池沼中分离得到单生卵囊藻(Oocystis solitaria)和月牙藻(Selenastrum sp.),分别研究了温度、光照强度、盐度对2种微藻生长繁殖的影响,分析了2种微藻的细胞组成、脂肪酸组成及盐度对2种微藻脂肪积累的影响.结果表明:单生卵囊藻和月牙藻的适宜生长温度分别为35.9℃～40.5℃和29.7℃～32.8℃;单生卵囊藻和月牙藻的适宜光照强度分别为46～70μmol · m-2·s-1和17 ～54 μmol·m-2·s-1;单生卵囊藻在淡水培养液中生长最好,月牙藻在盐度为2的半成水培养液中生长最好;在适宜培养条件下,单生卵囊藻细胞蛋白、总糖和总脂肪分别为27.61％、22.00％和3.84％;月牙藻细胞的蛋白、总糖和总脂肪分别为28.06％、21.99％和12.53％;单生卵囊藻的脂肪酸组成中含有丰富的18∶3n3;月牙藻的脂肪酸组成中含有DHA;盐度影响2种微藻的总脂肪含量;单生卵囊藻和月牙藻分别在盐度4和10的半咸水培养液中细胞总脂含量最高.     

固定化微藻对虾池弧菌数量动态的影响

引入固定化波吉卵囊藻(Oocystis borgei)和微绿球藻(Nannochloris oculata)于凡纳对虾(Litop Penaeus vannamei)养殖环境中,检测水体、对虾胃和后肠中弧菌的数量变化,研究固定化微藻对虾池弧数量动态影响。结果表明:波吉卵囊藻培养液中9d后不能检测出弧菌,微绿球藻培养液中15d后不能检测出弧菌。引入固定化波吉卵囊藻和微绿球藻的褐藻胶藻珠能抑制弧菌的生长,实验组养殖水体、对虾胃和后肠中弧菌的数量都比对照组低;抑制效果是固定化波吉卵囊藻和微绿球藻混合固定化波吉卵囊藻固定化微绿球藻;试验后期实验组弧菌的数量明显低于试验前期。试验期间固定化波吉卵囊藻和微绿球藻的生物量分别增加了约10倍和17倍,证明它们的生理活性不会因固定化而受干扰。因此,固定化微藻可应用于虾池微生态调控防病。       

4株微藻悬浮和固定培养生长和氮磷去除效果的比较

为了比较牟氏角毛藻(Chaetoceros muelleri)、蛋白核小球藻(Chlorella pyrenoidosa)、三角褐指藻(Phaeodactylum tricornutum)、新月柱鞘藻(Nitzschia closterium)四株微藻在悬浮和固定培养方式下藻细胞生长状况和氮磷去除效果,试验采取模拟含氮磷人工污水,向培养液中添加NH₄Cl,在相同培养条件下,分别培养4株微藻。实验结果表明:4株微藻在悬浮和固定化培养均能生长,氮磷去除效果良好。4种微藻悬浮培养的生长速率要优于固定化培养。两种培养方式生长速率均为:蛋白核小球藻>新月柱鞘藻>三角褐指藻>牟氏角毛藻;4种藻在悬浮培养下,NH₄⁺-N和PO₄^3--P去除率为:新月柱鞘藻>三角褐指藻>牟氏角毛藻>蛋白核小球藻;4种藻在固定化培养下,NH₄⁺-N和PO₄^3--P去除率为:新月柱鞘藻>...     

环境因子对小球藻(Chlorella sp.XQ-20044)光合作用的影响

小球藻(Chlorella sp.XQ-20044)是一株具有应用潜力的产油微藻,本文利用测定净光合放氧速率的方法研究了光照强度、温度、pH值和盐度对其光合作用的影响。研究结果表明:小球藻适宜的光照强度为500~1200μmol·m-2·s-1,光补偿点约30μmol·m-2·s-1,光饱和点在600μmol·m-2·s-1附近;光合作用适宜的温度范围为30~42.5℃,最适温度为40℃;适宜的pH值范围7.0~10.0,最适pH值为8.0;适宜盐度范围0.1~0.3 mol/L,最适盐度为0.2 mol/L。从光合作用特性来看,小球藻能适应较强的光照强度、较高的温度、偏碱性和较高的盐度环境,其中可耐受较高盐度的特性,有助于预防敌害生物的污染,对于实现规模培养,特别是利用开放系统进行规模培养较为有利。     

汾河水库及河道中优势硅藻生态位的研究

采用Levins生态位宽度公式和Petrailis生态位特定重叠指数测定了汾河水库和河道中 5 0个主要硅藻种的生态位宽度和生态位重叠 ,并对生态位宽度和生态位重叠的关系进行了初步探讨 ,结果表明 ,着生硅藻中的原子舟形藻、眼斑小环藻、平卧桥弯藻、尖菱形藻、短小舟形藻、线形曲壳藻、阿尔夫舟形藻等生态位最大 ,浮游硅藻中 ,以具星小环藻、团聚小环藻、眼斑小环藻生态位最宽 ;同时表明 ,生态位宽度大的种与其它种的生态位重叠也较大。生态位重叠表明 ,着生硅藻中 ,生态位重叠普遍偏高 ,河道中 ,清洁水体指示种普通等片藻进攻性最强 ,水库中以α -中污和 β-中污带生物比索曲壳藻进攻性最高。从生态位普遍重叠指数分析 ,浮游硅藻明显小于着生硅藻 ,表明浮游生境下 ,硅藻分化明显 ,着生环境中 ,硅藻对资源利用充分     

两种微藻改善虾池环境增强凡纳对虾抗病力的研究

人工引入波吉卵囊藻和微绿球藻于凡纳对虾养殖环境中,检测与凡纳对虾抗病力有关因子变化和测定主要水质因子,研究微藻生态调控对凡纳对虾抗病力的影响。结果表明,引入波吉卵囊藻和微绿球藻能改善养殖水体的水质,凡纳对虾的血细胞数目,血清蛋白的含量以及酚氧化酶、超氧化物歧化酶,溶菌酶,抗菌酶的活性都较对照组显提高。因此,微藻生态调控是防止对虾疾病的重要技术措施。     

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.