野生与笼养绿孔雀种群的随机扩增多态DNA研究

利用随机扩增多态DNA（RAPD）技术对野生14只和笼养18只绿孔雀（Pavo muticus）个体进行了种群遗传多样性分析。用23个随机引物,野生与笼养绿孔雀分别获得161和166个扩增片段,计算发现野生与笼养绿孔雀的种群内平均相对遗传距离分别是0.0555和0.1355,两种群间的为0.1635;两种群的Shannon多样性指数平均分别是0.4348和1.0163,有显著性差异。以上分析都显示野生绿孔雀的遗传多样性很低。用UPGMA法聚类显示两个种群都是分别来源于两个家系,可据此进行繁育管理。 Abstract:Random-amplified polymorphic DNA(RAPD) was used to investigate the genetic diversity of the population of 14 wild green peafowl and 18 captive green peafowl(pavo muticus).Total of 161 and 166 bands were obtained respectively,and 23 random primers were used to amplify the genomic DNA of the wild and captive green peafowls.The average relative hereditary distance of the wild and captive green peafowls is 0.0555 and 0.1355 respectively;and the Shannon diversity index is 0.4348 and 1.0163 respectively.There is a prominent differentia between the two populations by T-Test of HO.All the analyses above show that the genetic diversity is very low in wild green peafowl.It tells us that the two populations come from two families by using UPGMA,which can be useful in the breeding management in the future.     

大麦DNA单限制性酶切选择性扩增多态性技术及其优化

建立和优化了大麦DNA单限制性酶切选择性扩增多态性技术体系(SADF).分别用限制酶PstI、EcoRI和MseI酶切大麦基因组DNA,再与各自相应的人工接头连接,使用带三个选择碱基的引物进行选择性扩增.结果表明:采用分别优化建立的标准PCR扩增检测体系,六个识别碱基的PstI和EcoRI的SADF均能得到丰富稳定的带形,四个识别碱基的MseI不能得到明显谱带.SADF扩增产物片段大小范围为:PstI一般在200～2000bp,而EcoRI在200～1000bp;两者在不同大麦品种中均能检测到多态性,可用于不同大麦品种的检测,但PstI得到的带型明显优于EcoRI,在大麦中得到的片段具有范围宽、分布均匀、易于观察、多态性高等特点。 Abstract:A method named selective amplification DNA fragments (SADF) using single restrictive enzyme was established and optimized in barley.The barley genome DNA was first restricted into fragments of varied length with PstI,EcoRI and MseI respectively,then ligated with synthetic adapters.The ligated sets of fragments were used as templates for PCR amplification.Ideal amplification results could be obtained with different amplification procedure for PstI and EcoRI.Except MseI,both PstI and EcoRI could obtain abundant and reproducible bands,but SADF of PstI was more suitable for barley studies because of wider,more recognizable and polymorphic distribution of bands.     

Molecular phylogeography and evolutionary history of Picea likiangensis in the Qinghai-Tibetan Plateau inferred from mitochondrial and chloroplast DNA sequence variation

The aim of the present study was to examine the phylogeographic and evolutionary history of Picea likiangensis,a dominant species of the conifer forests in the eastern declivity of the Qinghai-Tibetan Plateau. We collected 422 individuals from 42 natural populations of three major varieties classified under this species.In conifers,mitochondrial(mt) DNA and chloroplast(cp) DNA dispersed by seeds or pollen experience very different levels of gene flow.To this end,we examined the sequence variation of two mtDNA fragments(nad5 intron 1 and nad1 intron b/c) and three cpDNA fragments(trnL-trnF,trnS-trnG and nadhK/C).We found that cpDNA probably introgressed from P.purpurea into remote populations of P.likiangensis through long-distance dispersal. Multiple refugia seem to have been maintained for P.likiangensis during the Last Glacial Maximum because the cpDNA and mtDNA haplotypes recovered were fixed in the different regions.Postglacial expansions were only detected at the distributional edges of this species where a single cpDNA or mtDNA haplotype was fixed in adjacent populations.However,genetic imprints of postglacial expansions from these two sets of markers were different in the western and southeastern regions,which may result from the long-distance dispersal of the cpDNA,as well as its fast lineage sorting during intraspecific divergences.Analysis of molecular variance further suggested that genetic differentiation between the three varieties is higher at cpDNA markers than at mtDNA markers,which supports the previous viewpoint that cpDNA markers with a high rate of gene flow may be more effective in delimitating closely related taxa.Together,the results of the present study highlight the evolutionary complexity of a widely distributed species owing to interactions among local and edge expansion,long-distance dispersal,and intraspecific divergences at two sets of DNA genomes with different rates of gene flow.     

Molecular characterization of a new type of cytoplasmic male sterile sugar beet

A line (named Cl) of cytoplasmic sterility of sugar beet whose cytoplasm derived from Betacicla Turkey was obtained by interspecific hybrid. Its cytoplasm and a spontaneous male sterile cytoplasm from wild beet Beta maritima (named M) were compared with that of Owen's sterile line (S-cms) and a common maintainer of them named N was used as control. RFLP and RAPD methods were mainly used in our experiments. The restriction fragment patterns of mtDNAs were found to be likely but for a few of specific low-lighted electrophoresis bands in Cl. The results of Southern hybridization of six heterogeneous mitochondrial genes as probes to digests of mtDNAs by six restriction enzymes showed to be analogous between S and M lines. But the Cl mtDNA was sorted out by hybridization of atpA probe. Difference of low-molecular-weight mitochondrial DNAs was found among the three sterile lines. Three RNA molecules weighing about 4.2kb stably existed in Cl mitochondria. Our results of RAPD also supported that the Cl cytoplas     

条纹斑竹鲨线粒体DNA的研究

用6种限制性内切酶分析了4条条纹斑竹鲨的线粒体DNA(mtDNA)。PstⅠ、Hpa Ⅰ、XbaⅠ、EcoRⅠ、EcoRⅤ、BglⅡ在条纹斑竹鲨mtDNA分子上分别具有0至2个切点, mtDNA分子大小为16.6kb,根据单酶和双酶完全酶解片段的大小,构建了条纹斑竹鲨mtDNA 的限制性酶切图谱。 Abstract:Mitochondrial DNA(mtDNA)form 4 samples of Chiloscyllium plagiosum was analyzed by 6 kinds of restriction.The number of cleavage sites were as follow:2 for HpaI,XbaI and EcoRI respectively;1 for BglII and EcoRV respectively;None for PstI.Molecular size of mtDNA was found to be 16.6kb.According to analysis of single and double enzyme cleavage,the map of restriction enzyme was constructed.     

Species identification refined by molecular scatology in a community of sympatric carnivores in Xinjiang,China

Many ecological studies and conservation management plans employ noninvasive scat sampling based on the assumption that species’ scats can be correctly identified in the field. However, in habitats with sympatric similarly sized carnivores, misidentification of scats is frequent and can lead to bias in research results. To address the scat identification dilemma, molecular scatology techniques have been developed to extract DNA from the donor cells present on the outer lining of the scat samples. A total of 100 samples were collected in the winter of 2009 and 2011 in Taxkorgan region of Xinjiang, China. DNA was extracted successfully from 88% of samples and genetic species identification showed that more than half the scats identified in the field as snow leopard(Panthera uncia) actually belonged to fox(Vulpes vulpes). Correlation between scat characteristics and species were investigated, showing that diameter and dry weight of the scat were significantly different between the species. However it was not possible to define a precise range of values for each species because of extensive overlap between the morphological values. This preliminary study confirms that identification of snow leopard feces in the field is misleading. Research that relies upon scat samples to assess distribution or diet of the snow leopard should therefore employ molecular scatology techniques. These methods are financially accessible and employ relatively simple laboratory procedures that can give an indisputable response to species identification from scats.     

PCR方法制备地高辛标记DNA探针检测中国对虾非包涵体型杆状病毒

A pair of primers created from information of PmNOBⅢ genome DNA Sal I fragment produced a 355bp band by using Penaeus chinensis non occluded baculovirus (PcNOBV),the WSBV isolate from P.hinensis in mainland China,as the DNA template.The specific PCR product was cloned,sequenced and labeled with digoxigenin (DIG)DNA labeling kit(Boehringer Mannheim).The DIG labeled fragment was tested by dot blot hybridization for sensitivity and specificity with purified PcNOBV nucleocapsid,PcNOBV infected shrimp tissues and healthy shrimp tissues.The detection limit of the DNA probe is 6.8pg of purified PcNOBV DNA.No hybridization signals were observed using DNA from healthy shrimp as template.Healthy P.chinensis,artificially infected P.chinensis and pond reared adult P.chinensis were screened for PcNOBV infection by both PCR and the hybridization assay.The results showed a good relationship between PCR and the hybridization assay.These findings demonstrate that the DIG labeled probe can be used as a sensitive,specific and cost effective reagent for detection of PcNOBV.     

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.