Description: Invasion of erythrocytes by merozoites is required in the life cycle of malarial parasites. Proteins derived from the invasive merozoites are essential ligands for erythrocyte recognition and penetration. In this study, we report a novel protein that possesses a Trx domain-like structure of the thioredoxin family and is expressed on the surface of merozoites of the malaria parasite Plasmodium falciparum . This protein, namely, PfTrx-mero protein, displayed a mutated sequence character at the Trx domain, but with a specific binding activity to human erythrocytes. Specific antibodies to the protein inhibited merozoite invasion into human erythrocytes. Immunization with a homologous protein of Plasmodium berghei strain ANKA also showed significant protection against lethal infection in mice. These results suggested that the novel PfTrx-like-mero protein expressed on the surface of merozoites is an important ligand participating in erythrocyte invasion and a potential vaccine candidate.

Description: The compound 3,5-dibromo-4-hydroxybenzoate (DBHB) is both anthropogenically released into and naturally produced in the environment, and its environmental fate is of great concern. Aerobic and anaerobic reductive dehalogenations are the only two reported pathways for DBHB catabolism. In this study, a new oxidative decarboxylation pathway for DBHB catabolism was identified in a DBHB-utilizing strain, Pigmentiphaga sp. strain H8. The genetic determinants underlying this pathway were elucidated based on comparative transcriptome analysis and subsequent experimental validation. A gene cluster comprising orf420 to orf426 , with transcripts that were about 33- to 4,400-fold upregulated in DBHB-induced cells compared with those in uninduced cells, was suspected to be involved in DBHB catabolism. The gene odcA ( orf420 ), which is essential for the initial catabolism of DBHB, encodes a novel NAD(P)H-dependent flavin monooxygenase that mediates the oxidative decarboxylation of DBHB to 2,6-dibromohydroquinone (2,6-DBHQ). The substrate specificity of the purified OdcA indicated that the 4-hydroxyl group and its ortho -halogen(s) are important for hydroxylation of the C-1 site carboxyl group by OdcA. 2,6-DBHQ is then ring cleaved by the dioxygenase OdcB (Orf425) to 2-bromomaleylacetate, which is finally transformed to β-ketoadipate by the maleylacetate reductase OdcC (Orf426). These results provide a better understanding of the molecular mechanism underlying the catabolic diversity of halogenated para -hydroxybenzoates. IMPORTANCE Halogenated hydroxybenzoates (HBs), which are widely used synthetic precursors for chemical products and common metabolic intermediates from halogenated aromatics, exert considerable adverse effects on human health and ecological security. Microbial catabolism plays key roles in the dissipation of halogenated HBs in the environment. In this study, the discovery of a new catabolic pathway for 3,5-dibromo-4-hydroxybenzoate (DBHB) and clarification of the genetic determinants underlying the pathway broaden our knowledge of the catabolic diversity of halogenated HBs in microorganisms. Furthermore, the NAD(P)H-dependent flavin monooxygenase OdcA identified in Pigmentiphaga sp. strain H8 represents a novel 1-monooxygenase for halogenated para -HBs found in prokaryotes and enhances our knowledge of the decarboxylative hydroxylation of (halogenated) para -HBs.

Description: Introduction High blood pressure (BP) affects over 40% of adults over the age of 25 worldwide and is the leading global risk factor for death or disability. Hypertension is also the most important risk factor for endovascular atherosclerosis, which, when combined with other cardiovascular risk factors, leads to atherosclerotic cardiovascular disease (ASCVD). Statins are one of the most widely used drugs for the prevention of ASCVD. The recently announced study of Heart Outcomes Prevention Evaluation-3 suggests that cholesterol-lowering agents combined with antihypertensive therapy can prevent cardiovascular events and reduce the combined endpoint. We plan to conduct a systematic review and meta-analysis to evaluate whether combined antihypertensive and statin therapy is more beneficial than antihypertensive therapy alone in patients with hypertension without complications. Methods and analysis We will perform a comprehensive search for randomised controlled trials evaluating combined antihypertensive and statin therapy for the treatment of patients with hypertension. The following English electronic databases will be searched: The Cochrane Library, EMBASE and PubMed. Outcomes will be categorised as short-term (≤6 months) or long-term (〉6 months). When evaluating the effects of combined antihypertensive and statin therapy, a short-term outcome is usually defined as a change in BP or lipid levels, while a long-term outcome is usually defined as cardiovascular benefits or risks. The data screening and extraction will be conducted by two different reviewers. The quality of the RCTs will be assessed according to the Cochrane handbook risk of bias tool. Ethics and dissemination This review does not require ethics approval and the results of the meta-analysis will be submitted to a peer-review journal. PROSPERO registration number CRD 42017071935 .

Description: Fungal β-1,3-glucanosyltransferases are cell wall-remodeling enzymes implicated in stress response, cell wall integrity, and virulence, with most fungal genomes containing multiple members. The insect-pathogenic fungus Beauveria bassiana displays robust growth over a wide pH range (pH 4 to 10). A random insertion mutant library screening for increased sensitivity to alkaline (pH 10) growth conditions resulted in the identification and mapping of a mutant to a β-1,3-glucanosyltransferase gene ( Bbgas3 ). Bbgas3 expression was pH dependent and regulated by the PacC transcription factor, which activates genes in response to neutral/alkaline growth conditions. Targeted gene knockout of Bbgas3 resulted in reduced growth under alkaline conditions, with only minor effects of increased sensitivity to cell wall stress (Congo red and calcofluor white) and no significant effects on fungal sensitivity to oxidative or osmotic stress. The cell walls of Bbgas3 aerial conidia were thinner than those of the wild-type and complemented strains in response to alkaline conditions, and β-1,3-glucan antibody and lectin staining revealed alterations in cell surface carbohydrate epitopes. The Bbgas3 mutant displayed alterations in cell wall chitin and carbohydrate content in response to alkaline pH. Insect bioassays revealed impaired virulence for the Bbgas3 mutant depending upon the pH of the media on which the conidia were grown and harvested. Unexpectedly, a decreased median lethal time to kill (LT 50 , i.e., increased virulence) was seen for the mutant using intrahemocoel injection assays using conidia grown at acidic pH (5.6). These data show that BbGas3 acts as a pH-responsive cell wall-remodeling enzyme involved in resistance to extreme pH (〉9). IMPORTANCE Little is known about adaptations required for growth at high (〉9) pH. Here, we show that a specific fungal membrane-remodeling β-1,3-glucanosyltransferase gene ( Bbgas3 ) regulated by the pH-responsive PacC transcription factor forms a critical aspect of the ability of the insect-pathogenic fungus Beauveria bassiana to grow at extreme pH. The loss of Bbgas3 resulted in a unique decreased ability to grow at high pH, with little to no effects seen with respect to other stress conditions, i.e., cell wall integrity and osmotic and oxidative stress. However, pH-dependent alternations in cell wall properties and virulence were noted for the Bbg as3 mutant. These data provide a mechanistic insight into the importance of the specific cell wall structure required to stabilize the cell at high pH and link it to the PacC/Pal/Rim pH-sensing and regulatory system.

Description: Dengue is an acute febrile illness caused by dengue virus (DENV) and a major cause of morbidity and mortality in tropical and subtropical regions of the world. The lack of an appropriate small-animal model of dengue infection has greatly hindered the study of dengue pathogenesis and the development of therapeutics. In this study, we conducted mass spectrometry-based serum metabolic profiling from a model using humanized mice (humice) with DENV serotype 2 infection at 0, 3, 7, 14, and 28 days postinfection (dpi). Forty-eight differential metabolites were identified, including fatty acids, purines and pyrimidines, acylcarnitines, acylglycines, phospholipids, sphingolipids, amino acids and derivatives, free fatty acids, and bile acid. These metabolites showed a reversible-change trend—most were significantly perturbed at 3 or 7 dpi and returned to control levels at 14 or 28 dpi, indicating that the metabolites might serve as prognostic markers of the disease in humice. The major perturbed metabolic pathways included purine and pyrimidine metabolism, fatty acid β-oxidation, phospholipid catabolism, arachidonic acid and linoleic acid metabolism, sphingolipid metabolism, tryptophan metabolism, phenylalanine metabolism, lysine biosynthesis and degradation, and bile acid biosynthesis. Most of these disturbed pathways are similar to our previous metabolomics findings in a longitudinal cohort of adult human dengue patients across different infection stages. Our analyses revealed the commonalities of host responses to DENV infection between humice and humans and suggested that humice could be a useful small-animal model for the study of dengue pathogenesis and the development of dengue therapeutics. IMPORTANCE Dengue virus is the most widespread arbovirus, causing an estimated 390 million dengue infections worldwide every year. There is currently no effective treatment for the disease, and the lack of an appropriate small-animal model of dengue infection has greatly increased the challenges in the study of dengue pathogenesis and the development of therapeutics. Metabolomics provides global views of small-molecule metabolites and is a useful tool for finding metabolic pathways related to disease processes. Here, we conducted a serum metabolomics study on a model using humanized mice with dengue infection that had significant levels of human platelets, monocytes/macrophages, and hepatocytes. Forty-eight differential metabolites were identified, and the underlying perturbed metabolic pathways are quite similar to the pathways found to be altered in dengue patients in previous metabolomics studies, indicating that humanized mice could be a highly relevant small-animal model for the study of dengue pathogenesis and the development of dengue therapeutics.

Description: Numerous viral pathogens are persistently transmitted by insect vectors and cause agricultural or health problems. These viruses circulate in the vector body, enter the salivary gland, and then are released into the apical plasmalemma-lined cavities, where saliva is stored. The cavity plasmalemma of vector salivary glands thus represents the last membrane barrier for viral transmission. Here, we report a novel mechanism used by a persistent virus to overcome this essential barrier. We observed that the infection by rice gall dwarf virus (RGDV), a species of the genus Phytoreovirus in the family Reoviridae , induced the formation of virus-associated filaments constructed by viral nonstructural protein Pns11 within the salivary glands of its leafhopper vector, Recilia dorsalis . Such filaments attached to actin-based apical plasmalemma and induced an exocytosis-like process for viral release into vector salivary gland cavities, through a direct interaction of Pns11 of RGDV and actin of R. dorsalis . Failure of virus-induced filaments assembly by RNA interference with synthesized double-stranded RNA targeting the Pns11 gene inhibited the dissemination of RGDV into salivary cavities, preventing viral transmission by R. dorsalis . For the first time, we show that a virus can exploit virus-induced inclusion as a vehicle to pass through the apical plasmalemma into vector salivary gland cavities, thus overcoming the last membrane barrier for viral transmission by insect vectors. IMPORTANCE Understanding how persistent viruses overcome multiple tissue and membrane barriers within the insect vectors until final transmission is the key for viral disease control. The apical plasmalemma of the cavities where saliva is stored in the salivary glands is the last barrier for viral transmission by insect vectors; however, the mechanism is still poorly understood. Here we show that a virus has evolved to exploit virus-induced filaments to perform an exocytosis-like process that enables viral passage through the apical plasmalemma into salivary cavities. This mechanism could be extensively exploited by other persistent viruses to overcome salivary gland release barriers in insect vectors, opening new perspectives for viral control.

Description: A characteristic clinical feature of dengue virus infection is thrombocytopenia, though its underlying mechanism is not definitively determined. By adoptive transfer of human CD34 + fetal liver cells into immunodeficient mice, we have constructed humanized mice with significant levels of human platelets, monocytes/macrophages, and hepatocytes. Infection of these mice with both lab-adapted and clinical strains of dengue virus induces characteristic human hematological changes, including transient leukopenia and thrombocytopenia. We show that the specific depletion of human platelets is not mediated by antibodies in the periphery or reduced production of human thrombopoietin in the liver but reduction of human megakaryocytes and megakaryocyte progenitors in the bone marrow of the infected mice. These findings identify inhibition of platelet production in the bone marrow as a key mechanism underlying dengue-induced thrombocytopenia and suggest the utility of the improved humanized mouse model in studying dengue virus infection and pathogenesis in a human cell context.

Description: We isolated a recombinant H9N2 avian influenza virus (AIV) from fresh egret feces in the Ardeidae protection region of the Dongting Lake wetland area in China, and it was designated A/Egret/Hunan/1/2012(H9N2). This is the first report of isolating H9N2 AIV from wild birds in the Dongting Lake wetland. Its eight gene segments are generated by reassortment of gene segments of different AIV subtypes. These results are helpful for understanding the epidemiology and evolution of AIV in wild birds during migration.

Description: Avian coronavirus infectious bronchitis virus (IBV) is variable, which causes many serotypes. Here we reported the complete genome sequences of two virulent IBV variants from China, GX-YL5 and GX-YL9, belonging to different serotypes. Differences between GX-YL5 and GX-YL9 were found mainly in stem-loop structure I in the predicted RNA secondary structure of open reading frame (ORF) 1b and the S protein gene fusion region, which will help us understand the molecular evolutionary mechanism of IBV and the disconcordance between the genotypes and serotypes of coronavirus.

Description: Sphingomonads DC-6 and DC-2 degrade the chloroacetanilide herbicides alachlor, acetochlor, and butachlor via N -dealkylation. In this study, we report a three-component Rieske non-heme iron oxygenase (RHO) system catalyzing the N -dealkylation of these herbicides. The oxygenase component gene cndA is located in a transposable element that is highly conserved in the two strains. CndA shares 24 to 42% amino acid sequence identities with the oxygenase components of some RHOs that catalyze N - or O -demethylation. Two putative [2Fe-2S] ferredoxin genes and one glutathione reductase (GR)-type reductase gene were retrieved from the genome of each strain. These genes were not located in the immediate vicinity of cndA . The four ferredoxins share 64 to 72% amino acid sequence identities to the ferredoxin component of dicamba O -demethylase (DMO), and the two reductases share 62 to 65% amino acid sequence identities to the reductase component of DMO. cndA , the four ferredoxin genes, and the two reductases genes were expressed in Escherichia coli , and the recombinant proteins were purified using Ni-affinity chromatography. The individual components or the components in pairs displayed no activity; the enzyme mixture showed N -dealkylase activities toward alachlor, acetochlor, and butachlor only when CndA-His 6 was combined with one of the four ferredoxins and one of the two reductases, suggesting that the enzyme consists of three components, a homo-oligomer oxygenase, a [2Fe-2S] ferredoxin, and a GR-type reductase, and CndA has a low specificity for the electron transport component (ETC). The N -dealkylase utilizes NADH, but not NADPH, as the electron donor.