Phylogenetic relationships of Sakhalin taimen <Emphasis Type="Italic">Parahucho perryi</Emphasis> inferred from PCR-RFLP analysis of mitochondrial DNA

RFLP analysis of three amplified mtDNA fragments (Cytb/D-loop, ND1/ND2, and ND3/ND4L/ND4) was performed in the following taxa: Parahucho perryi, Hucho taimen, Brachymystax lenok, B. tumensis, Salmo salar, Salvelinus leucomaenis, and S. levanidovi. For mtDNA of P. perryi, a substantial decrease in the haplotype and nucleotide diversity was observed as a result of random genetic drift, caused by a reduction in the effective population size. Nucleotide divergence estimates between the mtDNA haplotypes were determined. Sakhalin taimen P. perryi was found to be approximately equally diverged from S. salar and from the charrs of the genus Salvelinus, by 11.0 and 10.0%, respectively. The divergence between P. perryi and H. taimen constituted 14.6%, between P. perryi and lenoks of the genus Brachymystax, 14.2%, and between H. taimen and Brachymystax, 7.7%. The analysis of possible phylogenetic relationships of the mtDNA from P. perryi among the group of taxa examined confirmed validity of the genus Parahucho. Phylogenetic reconstructions performed showed that robustness of the trees constructed for the complex of phylogenetically informative characters over three mtDNA fragments was considerably higher than that of the trees constructed for individual genes.     

Recent advances in the identification of the host factors involved in dengue virus replication

Dengue virus (DENV) belongs to the genus Flavivirus of the family Flaviviridae and it is primarily transmitted via Aedes aegypti and Aedes albopictus mosquitoes. The life cycle of DENV includes attachment, endocytosis, protein translation, RNA synthesis, assembly, egress, and maturation. Recent researches have indicated that a variety of host factors, including cellular proteins and microRNAs, positively or negatively regulate the DENV replication process. This review summarizes the latest findings (from 2014 to 2016) in the identification of the host factors involved in the DENV life cycle and Dengue infection.

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Viral metagenomics analysis of feces from coronary heart disease patients reveals the genetic diversity of the <Emphasis Type="Italic">Microviridae</Emphasis>

Recent studies have declared that members of the ssDNA virus family Microviridae play an important role in multiple environments, as they have been found taking a dominant position in the human gut. The aim of this study was to analyze the overall composition of the gut virome in coronary heart disease (CHD) patients, and try to discover the potential link between the human gut virome and CHD. Viral metagenomics methods were performed to detect the viral sequences in fecal samples collected from CHD inpatients and healthy persons as controls. We present the analysis of the virome composition in these CHD patients and controls. Our data shows that the virome composition may be linked to daily living habits and the medical therapy of CHD. Virgaviridae and Microviridae were the two dominant types of viruses found in the enteric virome of CHD patients. Fourteen divergent viruses belonging to the family Microviridae were found, twelve of which were grouped into the subfamily Gokushovirinae, while the remaining two strains might represent two new subfamilies within Microviridae, according to the phylogenetic analysis. In addition, the genomic organization of these viruses has been characterized.

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Detection and characterization of diverse alpha- and betacoronaviruses from bats in China

Bats have been implicated as important reservoir hosts of alpha- and betacoronaviruses. In this study, diverse coronaviruses (CoVs) were detected in 50 of 951 (positive rate 5.3%) intestinal specimens of eight bat species collected in four provinces and the Tibet Autonomous Region of China by pan-coronavirus RT-PCR screening. Based on 400-nt RNA-dependent RNA polymerase (RdRP) sequence analysis, eight belonged to genus Alphacoronavirus and 42 to Betacoronavirus. Among the 50 positive specimens, thirteen gave rise to CoV full-length RdRP gene amplification for further sequence comparison, of which three divergent sequences (two from a unreported province) were subjected to full genome sequencing. Two complete genomes of betacoronaviruses (JTMC15 and JPDB144) and one nearly-complete genome of alphacoronavirus (JTAC2) were sequenced and their genomic organization predicted. The present study has identified additional numbers of genetically diverse bat-borne coronaviruses with a wide distribution in China. Two new species of bat CoV, identified through sequence comparison and phylogenetic analysis, are proposed.

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Assembly of long DNA sequences using a new synthetic <Emphasis Type="Italic">Escherichia coli</Emphasis>-yeast shuttle vector

Synthetic biology is a newly developed field of research focused on designing and rebuilding novel biomolecular components, circuits, and networks. Synthetic biology can also help understand biological principles and engineer complex artificial metabolic systems. DNA manipulation on a large genome-wide scale is an inevitable challenge, but a necessary tool for synthetic biology. To improve the methods used for the synthesis of long DNA fragments, here we constructed a novel shuttle vector named pGF (plasmid Genome Fast) for DNA assembly in vivo. The BAC plasmid pCC1BAC, which can accommodate large DNA molecules, was chosen as the backbone. The sequence of the yeast artificial chromosome (YAC) regulatory element CEN6-ARS4 was synthesized and inserted into the plasmid to enable it to replicate in yeast. The selection sequence HIS3, obtained by polymerase chain reaction (PCR) from the plasmid pBS313, was inserted for screening. This new synthetic shuttle vector can mediate the transformation-associated recombination (TAR) assembly of large DNA fragments in yeast, and the assembled products can be transformed into Escherichia coli for further amplification. We also conducted in vivo DNA assembly using pGF and yeast homologous recombination and constructed a 31-kb long DNA sequence from the cyanophage PP genome. Our findings show that this novel shuttle vector would be a useful tool for efficient genome-scale DNA reconstruction.

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Genetic polymorphism of commander islands polar foxes <Emphasis Type="Italic">Alopex lagopus semenovi</Emphasis> Ognev, 1931 and <Emphasis Type="Italic">Alopex lagopus beringiensis</Emphasis> Merriam, 1902

The polymorphism of the mitochondrial DNA (mtDNA) control region sequence was examined in 30 polar foxes from Bering Island and 30 polar foxes from Mednyi Island. Seven haplotypes were revealed in polar foxes from Bering Island, and one, in polar foxes from Mednyi Island. The age of divergence of these populations (12 000 ± 6 000 years) was calculated based on a fragment of the D-loop. In Bering polar foxes, the sequence nucleotide diversity (π) was 0.003 (S.D. = 0.002), the haplotype diversity h in Bering polar foxes was 0.835 (S.D. = 0.037). The effective number of females n the Bering Island population was estimated as 105 animals.     

Coexistence of multiple coronaviruses in several bat colonies in an abandoned mineshaft

Since the 2002–2003 severe acute respiratory syndrome(SARS) outbreak prompted a search for the natural reservoir of the SARS coronavirus, numerous alpha- and betacoronaviruses have been discovered in bats around the world. Bats are likely the natural reservoir of alpha- and betacoronaviruses, and due to the rich diversity and global distribution of bats, the number of bat coronaviruses will likely increase. We conducted a surveillance of coronaviruses in bats in an abandoned mineshaft in Mojiang County, Yunnan Province, China, from 2012–2013. Six bat species were frequently detected in the cave: Rhinolophus sinicus, Rhinolophus affinis, Hipposideros pomona, Miniopterus schreibersii, Miniopterus fuliginosus, and Miniopterus fuscus. By sequencing PCR products of the coronavirus RNA-dependent RNA polymerase gene(Rd Rp), we found a high frequency of infection by a diverse group of coronaviruses in different bat species in the mineshaft. Sequenced partial Rd Rp fragments had 80%–99% nucleic acid sequence identity with well-characterized Alphacoronavirus species, including Bt CoV HKU2, Bt CoV HKU8, and Bt CoV1,and unassigned species Bt CoV HKU7 and Bt CoV HKU10. Additionally, the surveillance identified two unclassified betacoronaviruses, one new strain of SARS-like coronavirus, and one potentially new betacoronavirus species. Furthermore, coronavirus co-infection was detected in all six bat species, a phenomenon that fosters recombination and promotes the emergence of novel virus strains. Our findings highlight the importance of bats as natural reservoirs of coronaviruses and the potentially zoonotic source of viral pathogens.     

Phylogenetic relationships of intraspecific forms of the house mouse Mus musculus: Analysis of variability of the control region (D-loop) of mitochondrial DNA

Analysis of the control region of mitochondrial DNA (mtDNA) or D-loop of 96 house mice (Mus musculus) from Russia, Moldova, Armenia, Azerbaijan, Kazakhstan, and Turkmenistan has been used to reconstruct the phylogenetic relationships and phylogeographic patterns of intraspecific forms. New data on the phylogenetic structure of the house mouse are presented. Three phylogroups can be reliably distinguished in the eastern part of the M. musculus species range, the first one mainly comprising the haplotypes of mice from Transcaucasia (Armenia); the second one, the haplotypes of mice from Kazakhstan; and the third one, the haplotypes of mice from Siberia and some other regions. The morphological subspecies M. m. wagneri and M. m. gansuensis have proved to be genetically heterogeneous and did not form discrete phylogroups in the phylogenetic tree.     

Polymorphism of the mitochondrial DNA control region in eight sturgeon species and development of a system for DNA-based species identification

Intraspecific and interspecific nucleotide sequence variations of the mtDNA control region (D-loop) were studied with mtDNAs isolated from tissue specimens of more than 1400 sturgeons of nine species: Russian sturgeon Acipenser gueldenstaedtii, Persian sturgeon A. persicus, Siberian sturgeon A. baerii, Amur sturgeon A. schrenkii, Fringebarbel sturgeon A. nudiventris, sterlet A. ruthenus, stellate sturgeon A. stellatus, beluga Huso huso, and kaluga H. dauricus. The results were used to analyze the interspecific variation of the mtDNA control region in the given set of species and to develop a test system of ten species-specific primers, which allowed species identification from noninvasive tissue samples, spawn, and food products of eight species. The system proved suitable for multiplex PCR. A method was developed for the first time to reliably differentiate the A. baerii mitotype and the baerii-like mitotype of A. gueldenstaedtii. It was found that, although genetically separate, A. gueldenstaedtii and A. persicus are relatively young species and have common mitochondrial haplotypes, precluding their identification via mtDNA analysis alone. To develop a system for species identification of A. gueldenstaedtii and A. persicus, it is necessary to study the polymorphism of nuclear markers.     

Phylogeography of mitochondrial DNA in South Asian Dolly Varden char <Emphasis Type="Italic">Salvelinus curilus</Emphasis> Pallas, 1814 (Salmoniformes,Salmonidae): Mediated gene introgression?

In 41 individuals of South Asian Dolly Varden char Salvelinus curilus, nucleotide sequences of tRNA-Pro gene fragment (27 bp) and mtDNA control region (483–484 bp) were analyzed. The fish were collected in 20 localities covering virtually the whole range of the species: Kuril Islands, Sakhalin Island, and Primorye. In addition, six individuals of three other char species (S. albus, S. malma, and S. leucomaenis), which are closely related to S. curilus and inhabit the Russian Far East, were examined. In all, we detected 12 different variants of mtDNA haplotypes that formed three distinct groups differing in 14–20 nucleotide positions. The first group consisted of six haplotypes found in S. curilus in Kuril Islands, Sakhalin, and Primorye (mtDNA phylogroup OKHOTSKIA). The second group comprised four haplotypes representing the mtDNA phylogroup BERING, which had been described earlier (Brunner et al, 2001); they were found in S. curilus in Kuril Islands and Sakhalin, as well as in S. albus and S. malma in Kamchatka and northern Kurils. The third group included two haplotypes detected in S. leucomaenis. The existence of two mtDNA lineages (OKHOTSKIA and BERING) in S. curilus from Kurils and Sakhalin was explained by hybridization and mtDNA transfer from S. malma to S. curilus. The absence of the BERING haplotypes in S. curilus from Primorye water reservoirs is related to the physical isolation of the Sea of Okhotsk and Sea of Japan basins in past epochs. On the basis of comparing phylogenetic trees, constructed from the data on allozyme and mtDNA variation, we suggest that in this case, a mediated transfer of mtDNA in Alpinoid chars → S. malma → S. curilus chain could occur.     

Zika virus and Zika fever

An emerging mosquito-borne arbovirus named Zika virus (ZIKV), of the family Flaviviridae and genus Flavivirus, is becoming a global health threat. ZIKV infection was long neglected due to its sporadic nature and mild symptoms. However, recently, with its rapid spread from Asia to the Americas, affecting more than 30 countries, accumulating evidences have demonstrated a close association between infant microcephaly and Zika infection in pregnant women. Here, we reviewed the virological, epidemiological, and clinical essentials of ZIKV infection.

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Association of single nucleotide polymorphism rs2065955 of the <Emphasis Type="Italic">filaggrin</Emphasis> gene with susceptibility to Epstein-Barr virus-associated gastric carcinoma and EBV-negative gastric carcinoma

The relationship between the Filaggrin gene (FLG) rs2065955 polymorphism and susceptibility to Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) and EBV-negative gastric carcinoma (EBVnGC) was investigated in Shandong Province, China. We detected the FLG rs2065955 genotype and allele distribution by using PCR and restriction fragment length polymorphism (RFLP) in 64 EBVaGC, 82 EBVnGC, and 111 normal control samples. Immunohistochemistry was used to detect the level of FLG protein in 35 EBVaGC and 51 EBVnGC tumor tissues. Compared with normal controls, the genotype CC and allele C of FLG rs2065955 showed higher frequency in EBVaGC and EBVnGC. There was no significant difference between EBVaGC and EBVnGC in allele distribution of FLG rs2065955, but the genotype CC was found more frequently in EBVaGC than in EBVnGC. The risk of developing either EBVaGC or EBVnGC in genotype CC was higher than in other genotypes. Furthermore, genotype CC of FLG rs2065955 may contribute more to the risk of developing EBVaGC than EBVnGC. There was no significant difference in the expression level of FLG protein between EBVaGC and EBVnGC. In conclusion, the FLG rs2065955 polymorphism was significantly related to gastric carcinoma. Allele C of FLG rs2065955 could be a risk factor for EBVaGC or EBVnGC, while genotype CC of FLG rs2065955 was especially associated with EBVaGC.

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Lack of association between integrin α<Subscript>v</Subscript>β<Subscript>3</Subscript> gene polymorphisms and hemorrhagic fever with renal syndrome in Han Chinese from Hubei,China

Hantaviruses belong to the family Bunyaviridae and cause hemorrhagic fever with renal syndrome (HFRS) in humans. β₃ integrins, including α_Vβ₃ and α_IIbβ₃ integrins, act as receptors on endothelial cells and play key roles in cellular entry during the pathogenesis of hantaviruses. Previous study demonstrated that the polymorphisms of integrin α_IIbβ₃ are associated with susceptibility to hantavirus infection and the disease severity of HFRS in Shaanxi Province of China, rather than in Finland. However, the polymorphisms of integrin α_vβ₃ in patients with HFRS was incompletely understood. Here, we aimed to investigate the associations between polymorphisms in human integrin α_vβ₃ and HFRS in Han Chinese individuals. Ninety patients with HFRS and 101 healthy controls were enrolled in this study. Analysis of five single nucleotide polymorphism (SNP) sites (rs3768777 and rs3738919 on ITGAV; rs13306487, rs5921, and rs5918 on ITGB3) was performed by TaqMan SNP genotyping assays and bi-directional PCR allele-specific amplification method. No significant differences were observed between the HFRS group and controls regarding the genotype and allele frequency distributions of any of the five SNP sites, and no associations were found between ITGAV polymorphisms/genotypes and disease severity. In conclusion, our results implied that these five SNPs in the integrin α_vβ₃ gene were not associated with HFRS susceptibility or severity in Han Chinese individuals in Hubei Province.

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Molecular detection of viruses in Kenyan bats and discovery of novel astroviruses,caliciviruses and rotaviruses

This is the first country-wide surveillance of bat-borne viruses in Kenya spanning from 2012–2015covering sites perceived to have medium to high level bat-human interaction. The objective of this surveillance study was to apply a non-invasive approach using fresh feces to detect viruses circulating within the diverse species of Kenyan bats. We screened for both DNA and RNA viruses;specifically, astroviruses(AstVs), adenoviruses(ADVs), caliciviruses(CalVs), coronaviruses(CoVs), flaviviruses, filoviruses, paramyxoviruses(PMVs), polyomaviruses(PYVs) and rotaviruses.We used family-specific primers, amplicon sequencing and further characterization by phylogenetic analysis. Except for filoviruses, eight virus families were detected with varying distributions and positive rates across the five regions(former provinces) studied. AstVs(12.83%), CoVs(3.97%), PMV(2.4%), ADV(2.26%), PYV(1.65%), CalVs(0.29%), rotavirus(0.19%) and flavivirus(0.19%). Novel CalVs were detected in Rousettus aegyptiacus and Mops condylurus while novel Rotavirus-A-related viruses were detected in Taphozous bats and R. aegyptiacus. The two Rotavirus A(RVA) strains detected were highly related to human strains with VP6 genotypes I2 and I16. Genotype I16 has previously been assigned to human RVA-strain B10 from Kenya only, which raises public health concern, particularly considering increased human-bat interaction.Additionally, 229E-like bat CoVs were detected in samples originating from Hipposideros bats roosting in sites with high human activity. Our findings confirm the presence of diverse viruses in Kenyan bats while providing extended knowledge on bat virus distribution. The detection of viruses highly related to human strains and hence of public health concern, underscores the importance of continuous surveillance.     

Genome analysis of Heliothis virescens ascovirus 3h isolated from China

No ascovirus isolated from China has been sequenced so far. Therefore, in this study, we aimed to sequence the genome of Heliothis virescens ascovirus 3h (HvAV-3h) using the 454 pyrosequencing technology. The genome was found to be 190,519-bp long with a G+C content of 45.5%. We also found that it encodes 185 hypothetical open reading frames (ORFs) along with at least 50 amino acids, including 181 ORFs found in other ascoviruses and 4 unique ORFs. Gene-parity plots and phylogenetic analysis revealed a close relationship between HvAV-3h and three other HvAV-3a strains and a distant relationship with Spodoptera frugiperda ascovirus 1a (SfAV-1a), Trichoplusia ni ascovirus 6a (TnAV-6a), and Diadromus pulchellus ascovirus 4a (DpAV-4a). Among the 185 potential genes encoded by the genome, 44 core genes were found in all the sequenced ascoviruses. In addition, 25 genes were found to be conserved in all ascoviruses except DpAV-4a. In the HvAV-3h genome, 24 baculovirus repeat ORFs (bros) were present, and the typical homologous repeat regions (hrs) were absent. This study supplies information important for understanding the conservation and functions of ascovirus genes as well as the variety of ascoviral genomes.

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Phylogeography of endangered <Emphasis Type="Italic">Dendrobium moniliforme</Emphasis> in East Asia based on mitochondrial DNA sequence variations

Belonging to the genus Dendrobium of Orchidaceae, Dendrobium moniliforme is an endangered species with disjunct distribution in East Asia, possessing significant medicinal value. To investigate its phylogeography, this study compared sequences of two mitochondrial DNA (mtDNA) fragments (nad 1/b-c and nad 7/2-3) from 143 samples of 18 natural populations of D. moniliforme almost covering the entire range of the Sino-Japanese Floristic Region (SJFR) of East Asia. As a result, a total of 30 mtDNA haplotypes were identified in these populations which revealed high levels of haplotype diversity (H _d  = 0.8733) and total genetic diversity (H _T  = 0.8886). Additionally, G _ST value being significantly lower (0.451) than N _ST value (0.722) (P < 0.05) indicated the presence of strong phylogeographic structure in these populations, and the network of mtDNA haplotypes showed that all haplotypes were divided into two clades (A and B). Haplotype overlap was observed among several D. moniliforme population groups in mainland China, suggesting the occurrence of ongoing and/or historical gene flow among them. No common haplotypes were shared by D. moniliforme populations from mainland China and the CKJ Islands (representing Taiwan [China], South Korea, and Japan collectively), pointing to their allopatric evolution in the two regions. Moreover, mismatch distribution analysis and neutral test of mtDNA data rejected the population expansion model. According to the mtDNA-based results, we infer that multiple refugia for D. moniliforme existed in the SJFR of East Asia during the Quaternary glacial period.