Tilapias are one of the most farmed fishes that are coined as “aquatic chicken” by the food industry. Nile tilapia and blue tilapia exhibit very recent transition of sex chromosome systems since their divergence approximately five million years ago, making them a great model for elucidating the molecular and evolutionary mechanisms of sex chromosome turnovers. Studies of their sex‐determining pathways are also critical for developing genetic sex control in aquaculture. We report here the newly produced genomes of Nile tilapia and blue tilapia that integrate long‐read sequencing and chromatin conformation data. The two nearly complete genomes have anchored over 97% of the sequences into linkage groups (LGs), and assembled majorities of complex repetitive regions including telomeres, centromeres and rDNA clusters. In particular, we inferred two episodes of repeat expansion at LG3 respectively in the ancestor of cichlids and that of tilapias. The consequential large heterochromatic region concentrated at one end of LG3 comprises tandem arrays of mRNA and small RNA genes, among which we have identified a candidate female determining gene Paics in blue tilapia. Paics shows female‐specific patterns of single‐nucleotide variants, copy numbers and expression patterns in gonads during early gonadogenesis. Our work provides a very important genomic resource for functional studies of cichlids, and suggested that unequal distribution of repeat content that impacts the local recombination rate might make some chromosomes more likely to become sex chromosomes.

H5N6 is a highly pathogenic avian influenza (HPAI) and a zoonotic disease that causes recurring endemics in East Asia. At least 155 H5N6 outbreaks, including 15 human infections, have been reported in China. These repeated outbreaks have increased concern that the H5N6 virus may cross over to humans and cause a pandemic. In February, 2016, peafowls in a breeding farm exhibited a highly contagious disease. Post-mortem examinations, including RT-PCR, and virus isolation, confirmed that the highly pathogenic H5N6 influenza virus was the causative agent, and the strain was named A/Pavo Cristatus/Jiangxi/JA1/2016. In animal experiments, it exhibited high pathogenicity in chickens and an estimated median lethal dose in mice of ~104.3 TCID50. A phylogenetic analysis showed that JA1/2016 was clustered in H5 clade 2.3.4.4. FG594-like H5N6 virus from Guangdong Province was the probable predecessor of JA1/2016, and the estimated divergence time was June 2014. Furthermore, we found that H5N6 influenza viruses can be classified into the two following groups: Group 1 and Group 2. Group 2 influenza viruses have not been detected since the end of 2014, whereas Group 1 influenza viruses have continually evolved and reassorted with the “gene pool” circulating in south China, resulting in the rise of novel subtypes of this influenza virus. An increase in the number of its identified hosts, the expanding range of its distribution, and the continual evolution of H5N6 AIVs enhance the risk that an H5N6 virus may spread to other continents and cause a pandemic.

Hypertension is regarded as the most prominent risk factor for cardiovascular diseases, which have become a primary cause of death, and recent research has demonstrated that chronic inflammation is involved in the pathogenesis of hypertension. Both innate and adaptive immunity are now known to promote the elevation of blood pressure by triggering vascular inflammation and microvascular remodeling. For example, as an important part of innate immune system, classically activated macrophages (M1), neutrophils, and dendritic cells contribute to hypertension by secreting inflammatory cy3tokines. In particular, interferon-gamma (IFN-γ) and interleukin-17 (IL-17) produced by activated T lymphocytes contribute to hypertension by inducing oxidative stress injury and endothelial dysfunction. However, the regulatory T cells and alternatively activated macrophages (M2) may have a protective role in hypertension. Although inflammation is related to hypertension, the exact mechanisms are complex and unclear. The present review aims to reveal the roles of inflammation, immunity, and oxidative stress in the initiation and evolution of hypertension. We envisage that the review will strengthen public understanding of the pathophysiological mechanisms of hypertension and may provide new insights and potential therapeutic strategies for hypertension.

19Background 20Tilapias are one of the most farmed fishes that are coined as 'aquatic chicken' by the 21 food industry. Like many other teleosts, Nile tilapia and blue tilapia exhibit very recent 22 transition of sex chromosome systems since their divergence about 5 million years ago, 23making them a great model for elucidating the molecular and evolutionary mechanisms 24 of sex chromosome turnovers. Studies into their sex-determining pathways are also 25 critical for developing genetic sex control in aquaculture. 26Results 27 We report here the newly produced genomes of Nile tilapia and blue tilapia that 28integrate long-read sequencing and chromatin conformation data. The two nearly 29 complete genomes have anchored over 97% of the sequences into linkage groups 30 (LGs), and assembled majorities of complex repetitive regions including telomeres, 31centromeres and rDNA clusters. In particular, we inferred two episodes of repeat 32 expansion at LG3 respectively in the ancestor of cichlids and that of tilapias. The 33 consequential large heterochromatic region concentrated at one end of LG3 comprises 34 tandem arrays of mRNA and small RNA genes, among which we have identified a 35 candidate female determining gene Paics in blue tilapia. Paics show female-specific 36 patterns of single-nucleotide variants, copy numbers and expression patterns in gonads 37 during early gonadogenesis. 38Conclusions 39Our work provide a very important genomic resource for functional studies of cichlids, 40and suggested that unequal distribution of repeat content that impacts the local 41 recombination rate might make some chromosomes more likely to become sex 42 chromosomes. 43There is a strong and persistent interest in studying the tilapia SD mechanisms 65 and sex chromosomes, in order to produce all-male fingerlings, and also to use tilapias 66 as a model to unravel the molecular and evolutionary mechanisms of vertebrate sex 67 chromosome turnovers [8][9][10]. In contrast to the conserved and stable sex 68 chromosomes within mammals, birds or Drosophila, teleost fish harbor a remarkable 69 diversity of male heterogametic (XY, like that of mammals), female heterogametic (ZW, 70 like that of birds), and environmental SD (ESD) mechanisms frequently between sister 71 species [11][12][13]. Fish sex chromosomes also do not usually exhibit a high degree of 72 differentiation [13][14][15], which hampers the identification of the sex chromosomes or the 73 4 exact SD region cytologically. Some species like ON combine both GSD and ESD, 74suggesting sex in these species is a threshold trait that can be determined by genetic 75 and environmental factors [9]. Despite the complexity of SD systems, and a lack of 76 abundant genomic resources and functional genetic tools until very recently, there have 77 been great efforts of mapping the SD regions among the tilapia species. Early 78 inspection of synaptonemal complex speculated that a large pair of chromosomes 79 corresponding to linkage group 3 (LG3) with incomplete pairing at its terminals mayb...

No abstract

Bungarus multicinctus is the most venomous snake distributed in China and neighboring countries of Myanmar, Laos, north Vietnam and Thailand. The high mortality rate of B. multicinctus envenomation is attributed to the lethal components of α-, β-, γ- and κ- bungarotoxins contained in the venom. Although anti-B. multicinctus sera were produced in Shanghai, Taiwan and Vietnam, the most widely clinic used product was term as B. multicinctus antivenin and manufactured by Shanghai Serum Bio-technology Co. Ltd. In the present investigation, high purity α-, β- and γ-bungarotoxins were separately isolated from B. multicinctus crude venom. Rabbit anti- α-, β- and γ-bungarotoxin antisera were prepared by common methods, respectively. LD50 values of α-, β- and γ-bungarotoxins were systematically determined via three administration pathways (intraperitoneal, intramuscular and intravenous injections) in Kunming mice. LD50 values of β-bungarotoxin were closely related with injection routines but those of both α- and γ-bungarotoxins were not dependent on the injection routines. Commercial B. multicinctus antivenin showed strong immunoreaction with high molecular weight fractions of the B. multicinctus but weakly recognized low molecular weight fractions like α- and γ-bungarotoxins. Although B. multicinctus antivenin showed immunoreaction with high molecular weight fractions of Bungarus fasciatus, Naja atra, Ophiophagus hannah venoms but the antivenin only demonstrated animal protection efficacy against O. hannah venom. These results indicated that the high molecular weight fractions of the O. hannah played an important role in venom lethality but those of B. fasciatus and N. atra did not have such a role.

Background Avian influenza A (H5N6) virus poses a great threat to the human health since it is capable to cross the species barrier and infect humans. Although human infections are believed to largely originate from poultry contaminations, the transmissibility is unclear and only limited information was available on poultry environment contaminations, especially in Fujian Province. Methods A total of 4901 environmental samples were collected and tested for Avian Influenza Virus (AIV) from six cities in Fujian Province through the Fujian Influenza Surveillance System from 2013 to 2017. Two patient-related samples were taken from Fujian’s first confirmed H5N6 human case and his backyard chicken feces in 2017. Chi- square test or Fisher’s exact probability test was used to compare the AIV and the viral subtype positive rates among samples from different Surveillance cities, surveillance sites, sample types, and seasons. Phylogenetic tree analysis and molecular analysis were conducted to track the viral transmission route of the human infection and to map out the evolutions of H5N6 in Fujian. Results The overall positive rate of the H5 subtype AIVs was 4.24% (208/4903). There were distinctive differences ( p < 0.05) in the positive rates in samples from different cities, sample sites, sample types and seasons. The viruses from the patient and his backyard chicken feces shared high homologies (99.9–100%) in all the eight gene segments. Phylogenetic trees also showed that these two H5N6 viruses were closely related to each other, and were classified into the same genetic clade 2.3.4.4 with another six H5N6 isolates from the environmental samples. The patient’s H5N6 virus carried genes from H6N6, H5N8 and H5N6 viruses originated from different areas. The R294K or N294S substitution was not detected in the neuraminidase (NA). The S31 N substitution in the matrix2 (M2) gene was detected but only in one strain from the environmental samples. Conclusions The H5 subtype of AIVs has started circulating in the poultry environments in Fujian Province. The patient’s viral strain originated from the chicken feces in his backyard. Genetic reassortment in H5N6 viruses in Fujian Province was indicated. The H5N6 viruses currently circulating in Fujian Province were still commonly sensitive to Oseltamivir and Zanamivir, but the resistance against Amantadine has emerged. Electronic supplementary material The online version of this article (10.1186/s12879-019-4145-6) contains supplementary material, which is available to authorized users.

No abstract