Function and distribution of nitrogen-cycling microbial communities in the Napahai plateau wetland.

Nitrogen is an essential component of living organisms and a major nutrient that limits life on Earth. Until now, freely available nitrogen mainly comes from atmospheric nitrogen, but most organisms rely on bioavailable forms of nitrogen, which depends on the complex network of microorganisms with a wide variety of metabolic functions. Microbial-mediated nitrogen cycling contributes to the biogeochemical cycling of wetlands, but its specific microbial abundance, composition, and distribution need to be studied. Based on the metagenomic data, we described the composition and functional characteristics of microbial nitrogen cycle-related genes in the Napahai plateau wetland. Six nitrogen cycling pathways existed, such as dissimilatory nitrate reduction, denitrification, nitrogen fixation, nitrification, anammox, and nitrate assimilation. Most genes related to the nitrogen cycling in this region come from bacteria, mainly from Proteobacteria and Acidobacteria. Habitat types and nitrogen cycle-related genes largely explained the relative abundance of total nitrogen pathways. Phylogenetic trees were constructed based on nitrogen cycle-related genes from different habitats and sources, combined with PCoA analysis, most of them clustered separately, indicating richness and uniqueness. Some microbial groups seemed to be special or general in the nitrogen cycling. In conclusion, it suggested that microorganisms regulated the N cycling process, and may lead to N loss throughout the wetland, thus providing a basis for further elucidation of the microbial regulation of N cycling processes and the Earth's elemental cycles.

Salmonella enterica serovar Paratyphi A-induced immune response in Caenorhabditis elegans depends on MAPK pathways and DAF-16.

Salmonella enterica serovar Paratyphi A (S. Paratyphi A) is a pathogen that can cause enteric fever. According to the recent epidemic trends of typhoid fever, S. Paratyphi A has been the major important causative factor in paratyphoid fever. An effective vaccine for S. Paratyphi A has not been developed, which made it a tricky public health concern. Until now, how S. Paratyphi A interacts with organisms remain unknown. Here using lifespan assay, we found that S. Paratyphi A could infect Caenorhabditis elegans (C. elegans) at 25°C, and attenuate thermotolerance. The immune response of C. elegans was mediated by tir-1, nsy-1, sek-1, pmk-1, mpk-1, skn-1, daf-2 and daf-16, suggesting that S. Paratyphi A could regulate the MAPK and insulin pathways. Furthermore, we observed several phenotypical changes when C. elegans were fed S. Paratyphi A, including an accelerated decline in body movement, reduced the reproductive capacity, shortened spawning cycle, strong preference for OP50, arrested pharyngeal pumping and colonization of the intestinal lumen. The virulence of S. Paratyphi A requires living bacteria and is not mediated by secreting toxin. Using hydrogen peroxide analysis and quantitative RT-PCR, we discovered that S. Paratyphi A could increase oxidative stress and regulate the immune response in C. elegans. Our results sheds light on the infection mechanisms of S. Paratyphi A and lays a foundation for drugs and vaccine development.

Chemoselective Condensation of 3-Amino-2-cyclohexenones with Cinnamaldehydes: Switchable Synthesis of Dihydroquinolinones and Hexahydroacridinediones.

Herein, a chemoselective condensation of 3-amino-2-cyclohexenones and cinnamaldehydes for switchable synthesis of dihydroquinolinones and hexahydroacridinediones was developed. Mechanism analysis showed that the formation of dihydroquinolinones involved trimolecular condensation and oxidative aromatization, while the formation of hexahydroacridinediones involved acid hydrolysis of enaminone and dehydration-aromatization. This strategy provides a convenient way to switch from the same substrates to produce two different quinolinone derivatives.

Isolation and characterization of two novel serotypes of Tibet orbivirus from Culicoides and sentinel cattle in Yunnan Province of China.

Tibet orbivirus (TIBOV), a new candidate of Orbivirus genus, was initially isolated from mosquitoes in Tibet in 2009 and subsequently from both Culicoides and mosquitoes in several provinces of China and Japan. Little is known about the origin, genetic diversity, dissemination and pathogenicity of TIBOV, although its potential threat to animal health has been acknowledged. In this study, two viruses, V290/YNSZ and V298/YNJH, were isolated from the Culicoides and sentinel cattle in Yunnan Province. Their genome sequences, cell tropism in mammalian and insect cell lines along with pathogenicity in suckling mice were determined. Genome phylogenetic analyses confirmed their classification as TIBOV species; however, OC1 proteins of the V290/YNSZ and V298/YNJH shared maximum sequence identities of 31.5% and 33.9% with other recognized TIBOV serotypes (TIBOV-1 to TIBOV-4) and formed two monophyletic branches in phylogenetic tree, indicating they represented two novel TIBOV serotypes which were tentatively designated as TIBOV-5 and TIBOV-6. The viruses replicated robustly in BHK, Vero and C6/36 cells and triggered overt clinical symptoms in suckling mice after intracerebral inoculation, causing mortality of 100% and 25%. Cross-sectional epidemiology analysis revealed silent circulation of TIBOV in Yunnan Province with overall prevalence of 16.4% (18/110) in cattle, 10.8% (13/120) in goats and 5.5% (6/110) in swine. The prevalence patterns of four investigated TIBOV serotypes (TIBOV-1, -2, -5 and 6) differed from each one another, with their positive rates ranging from 8.2% (9/110) for TIBOV-2 in cattle to 0.9% (1/110) for TIBOV-1 and TIBOV-5 in cattle and swine. Our findings provided new insights for diversity, pathogenicity and epidemiology of TIBOV and formed a basis for future studies addressing the geographical distribution and the zoonotic potential of TIBOV.

Tumor-Promoting ATAD2 and Its Preclinical Challenges.

ATAD2 has received extensive attention in recent years as one prospective oncogene with tumor-promoting features in many malignancies. ATAD2 is a highly conserved bromodomain family protein that exerts its biological functions by mainly AAA ATPase and bromodomain. ATAD2 acts as an epigenetic decoder and transcription factor or co-activator, which is engaged in cellular activities, such as transcriptional regulation, DNA replication, and protein modification. ATAD2 has been reported to be highly expressed in a variety of human malignancies, including gastrointestinal malignancies, reproductive malignancies, urological malignancies, lung cancer, and other types of malignancies. ATAD2 is involved in the activation of multiple oncogenic signaling pathways and is closely associated with tumorigenesis, progression, chemoresistance, and poor prognosis, but the oncogenic mechanisms vary in different cancer types. Moreover, the direct targeting of ATAD2's bromodomain may be a very challenging task. In this review, we summarized the role of ATAD2 in various types of malignancies and pointed out the pharmacological direction.

[Advances of Researches on Anti-phage Mechanisms of Host].

Phages also known as bacteria viruses, are recognized as the most abundant and diverse microbes. This diversity is adapting to the selective pressures such as the prevalence of the phage resistance mechanisms of bacteria. Phages invade and lyse bacterial through six steps (adsorption, injection, replication, transcription translation, assemble, release). Bacteria evolve to many anti-phage mechanisms to avoid phage infection and lysis. This paper focus on a variety of anti-phage mechanisms of bacteria.

Complete Genome Sequence of the Salmonella enterica Serovar Paratyphi A Bacteriophage LSPA1 Isolated in China.

The bacteriophage LSPA1 was isolated from hospital sewage (Kunming, China), and lytic activity was demonstrated against the Salmonella enterica serovar Paratyphi A CMCC50973 strain. This bacteriophage has a 41,880-bp double-stranded DNA (dsDNA) genome encoding 58 coding sequences (CDSs) and belongs to the family Siphoviridae.

Simian foamy virus prevalence in Macaca mulatta and zookeepers.

The simian foamy virus (SFV) has been reported to be transmissible among humans occupationally exposed to nonhuman primates. Nevertheless, epidemiological and genotypic data on the SFV in Macaca mulatta and zookeepers in China are limited. In the present study, SFV proviral DNA was detected in 74 blood samples from M. mulatta and 12 saliva specimens from zookeepers by nested polymerase chain reaction. A total of 29 blood samples from M. mulatta (29/74, 39.19%) and two saliva specimens from zookeepers (2/12, 16.67%) were positive. The phylogenetic analysis indicated that these SFV strains shared the highest homology with Macaca fascicularis (93.4%). The two SFV strains infected human beings, and shared the highest homology of 98.6% with each other as well as 90.8-99.5% with M. mulatta. The investigation revealed the high prevalence of the SFV in M. mulatta in China and its zoonotic transmission to humans.

Seroepidemiology and molecular characterization of hepatitis E Virus in Macaca mulatta from a village in Yunnan, China, where infection with this virus is endemic.

BACKGROUND: Hepatitis E virus (HEV) infection is a significant public health concern and has been identified as a zoonotic infection. OBJECTIVES: Since no reports have characterized the epidemiological and genotypic features of HEV infections in Macaca mulatta (rhesus macaques) from Yunnan, China, where swine HEV infections are endemic, we aimed to investigate these characteristics. MATERIALS AND METHODS: Seroepidemiological and molecular characterization of HEV in both Macaca mulatta and pigs from the Yunnan province of China were conducted using enzyme-linked immunosorbent assay (ELISA) and reverse transcription-nested PCR (RT-nPCR). Four hundred and eighty-two stool samples (320 from Macaca mulatta and 162 from pigs) and 92 serum samples (all from Macaca mulatta) were collected for the detection of HEV RNA and anti-HEV antibodies (IgG/IgM). RESULTS: Thirty-three rhesus macaques (35.87%) were positive for HEV IgG. Of these, 3 were also positive for HEV IgM. Four different strains of swine HEV RNA were detected in pigs; however, we failed to detect any in Macaca mulatta. CONCLUSIONS: Results indicate that Macaca mulatta may not be a natural reservoir of HEV.

[Construction and identification of ureB gene vaccine of H. pylori].

AIM: To clone ureB gene of H.pylori and construct its gene vaccine. METHODS: ureB gene was amplified by PCR from genome of H. pylori 11637 strain and subcloned into pMD18-T vector. The vector digested with restriction enzyme (Sal I and Bgl II) was inserted into pTCAE and transformed into E. coli DH5alpha. The positive recombinant plasmid identified by digesting with restriction enzyme (Sal I and Xho I) and sequencing named pT-ureB. The pT-ureB was transfected into CHO cells by electroporation method. The expression of UreB protein was detected by Western blot. RESULTS: The pT-ureB was obtained by cloning and recombinant DNA technique. The Western blot analysis showed that the expression of UreB protein (M(r)approximately 62,000) was detected in culture supernatant of CHO cells following transfection with pT-ureB. CONCLUSION: UreB DNA vaccine of H. pylori was successfully constructed. The expression of UreB protein can be detected in culture supernatants of transfected CHO cells.

Restriction fragment length polymorphism of adhesin gene hpaA from different Helicobacter pylori strains of Chongqing, China.

AIM: To assess the variability of adhesin gene hpaA between different Helicobacter pylori (H pylori) strains with PCR-restriction fragment length polymorphism (RFLP). METHODS: Twelve different H pylori strains were chosen to amplify the 710-bp segments of gene hpaA. These strains were NCTC11637, SS1; Chongqing clinical isolates CCS9801, CCS9802, CCS9803, CCS9806, CCS9809, CCS9810, CCS9813, which were gained from patients of gastritis; Mongolia gerbil adapted H pylori strains (abbreviation MG), which were gained from the following steps: gastric mucosal specimens of Mongolia gerbils infected by clinical isolate CCS9803 were cultured and detected, the positive H pylori strains were named as the first generation of Mongolia gerbil adapted H pylori strains (abbreviation MG1) and then were subcultured with healthy Mongolia gerbil to generate MG2, in turn to gain the ninth generation (abbreviation MG9). All hpaA segments, obtained from 12 different H pylori strains, were digested by HhaI and HaeIII individually and analyzed by agarose gel electrophoresis. RESULTS: In all 12 strains, the 710-bp PCR products were successfully amplified and products were cloned to pMD18-T vector respectively, then the recombinant plasmids were digested simultaneously with NcoI and XhoI to recover the small fragments. The objective fragments from 12 different H pylori strains digested with Hae III could be seen as 4 types of bands and 5 types with Hha I. According to the hpaA RFLP patterns, the 12 H pylori strains could be divided into 5 groups: group I, NCTC11637 and SS1; group II, CCS9809, which RFLP type digested with HaeIII was the same as strains of group I, but HhaI RFLP showed difference compared with the other groups; group III, CCS9810; group IV, CCS9803; group V: CCS9801, CCS9802, CCS9806, CCS9813, MG1, MG3 and MG9. The sequence data of 12 hpaA segments were analyzed by DNAsis software and it was observed that: (1) The homologies of base pair and amino acid sequence between strains NCTC11637, SS1, CCS9809 were 99.6% and 98.9%, respectively; (2) The homology of base pair and amino acid sequence between CCS9803 and CCS9810 was 97.7% and 99.1%; (3) That of the rest strains, CCS9801, CCS9802, CCS9806, CCS9813, MG1, MG3, MG9 reached 99.4% and 98.4%; (4) The base pair homologies between all hpaA fragments of different sources were higher than 94.6%, therefore the correspondence of deduced amino acid sequence was higher than 96.8% between each other. CONCLUSION: The gene hpaA from different H pylori strains revealed variation, and this might provide an effective method for molecular epidemiological survey of H pylori.

[Immunopotency of the recombinant urease B subunit vaccine of Helicobacter pylori after intranasal administration to mice].

AIM: To observe the immunopotency of the recombinant urease B subunit (rUreB) of Helicobacter pylori after intranasal administration to mice. MDTHODS: BALB/c mice were immunized intranasally with rUreB of 20 microg,10 microg and rUreB plus different adjuvants, such as cholera toxin B subunit (CTB), Escherichia coli heat labile enterotoxin B subunit (LTB) and carbopol respectively, four times at an intervals of 7 days. The serum and washing solution from gastric, intestinal, nasal and tracheal mucosas were collected in 7 days after final immunization. IgG and IgA antibodies specific for rUreB were detected by ELISA. RESULTS: The levels of IgA and IgG antibodies in sera every groups of mice immunized intranasally were significantly increased compared with control group (P<0.01). Only the levels of serum IgG of mice immunized with 20 microg dose were higher than those of mice immunized with 10 microg dose. Carbopol could enhance the level of IgA antibodies in washing solution from mouse gastric mucosa after intranasal immunization. The efficacy of LTB as a nasal mucosal immuno-adjuvant was stronger than that of CTB. CONCLUSION: CTB, LTB and carbopol can play the role of adjuvant in nasal mucosal immunization. Intranasal immunization with rUreB can induce not only serum IgG antibody production but also antibody responses of different mucosa. Thus intranasal inoculation is a convenient, effective and cheap immunization way.