160 research outputs found

    A broad-host-range lytic phage vB_VhaS-R18L as a candidate against vibriosis

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    Vibriosis is one of the most common bacterial diseases that cause high rates of mortality and considerable economic losses in aquaculture. Phage therapy has been considered as a promising alternative method to antibiotics in the biocontrol of infectious diseases. Genome sequencing and characterization of the phage candidates are prerequisites before field applications to ensure environmental safety. In this study, a lytic phage, named vB_VhaS-R18L (R18L), was isolated from the coastal seawater of Dongshan Island, China. The phage was characterized in terms of morphology, genetic content, infection kinetics, lytic profile, and virion stability. Transmission electronic microscopy indicated that R18L is siphovirus-like, comprising an icosahedral head (diameter 88.6 ± 2.2 nm) and a long noncontractile tail (225 × 11 nm). Genome analysis indicated R18L to be a double-stranded DNA virus with a genome size of 80,965 bp and a G + C content of 44.96%. No genes that encode known toxins or genes implicated in lysogeny control were found in R18L. A one-step growth experiment showed that R18L had a latent period of approximately 40 min and a burst size of 54 phage particles per infected cell. R18L showed lytic activity against a wide range of at least five Vibrio species (V. alginolyticus, V. cholerae, V. harveyi, V. parahemolyticus, and V. proteolyticus). R18L was relatively stable at pH 6–11 and at temperatures ranging from 4°C to 50°C. The broad lytic activity across Vibrio species and the stability in the environment make R18L a potential candidate for phage therapy in controlling vibriosis in aquaculture systems

    Application of UPLC to separation and analysis of ginsenosides from cultivated ginseng and forest-grown wild ginseng

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    In the past years, much attention has been paid to Panax ginseng, mainly referring to Cultivated Ginseng (CG), but few studies have also been focused on Forest-grown Wild Ginseng (FWG). FWG has been included in the 2010 edition Pharmacopoeia of The Peoples Republic of China, as a substitute for wild ginseng. This paper compared and determined the variety and changes of ginsenosides in CG and FWG by UPLC. The results demonstrated that the content of every ginsenoside was the highest at tenyear-old FWG, but the lowest at fourteen-year-old FWG. Pharmacological activity varies for different ginsenosides, therefore, this study will provide a scientific reference for clinical applications of FWG.Comunicación breveShort communicationComunicação breveColegio de Farmacéuticos de la Provincia de Buenos Aire

    Prosaposin in seminal plasma on the day of oocyte retrieval is associated with normal fertilization and embryo development in in vitro fertilization cycles.

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    The prospective study including 166 participants aims to evaluate the association between seminal prosaposin and the outcomes of in vitro fertilization (IVF) cycles in humans. The generalized linear model (GLM) was used to analyze the associations between seminal prosaposin concentrations and normal fertilization rates and good embryos proportion. The generalized estimating equation (GEE) was used to evaluate the association between embryo parameters and the prosaposin concentrations. Each model was adjusted for age of the couples, female basal FSH, AFC and BMI, starting dose and oocyte yield of IVF cycles and smoker. GLM models suggested that prosaposin was significantly associated with fertilization rate ( P = 0.005) and good embryo proportion ( P = 0.038) while none of the semen parameters (sperm concentration, motility, progressive motility, normal morphology rate, postwash sperm concentration and motility) was significantly associated with the parameters in the cohort. Using GEE, it was also shown that prosaposin was positively associated with the occurrence of early cleavage and negatively associated with uneven cleavage pattern on day 3. In both the overall population and the normozoospermia patients, the prosaposin was significantly associated with pregnancy with adjustment with covariates. In conclusion, our data suggested that seminal prosaposin concentration could provide more information regarding normal fertilization and embryo development in IVF than traditional semen parameters

    A newly isolated roseophage represents a distinct member of Siphoviridae family.

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    BACKGROUND(#br)Members of the Roseobacter lineage are a major group of marine heterotrophic bacteria because of their wide distribution, versatile lifestyles and important biogeochemical roles. Bacteriophages, the most abundant biological entities in the ocean, play important roles in shaping their hosts’ population structures and mediating genetic exchange between hosts. However, our knowledge of roseophages (bacteriophages that infect Roseobacter) is far behind that of their host counterparts, partly reflecting the need to isolate and analyze the phages associated with this ecologically important bacterial clade.(#br)METHODS(#br)vB_DshS-R4C (R4C), a novel virulent roseophage that infects Dinoroseobacter shibae DFL12T, was isolated with the double-layer agar method. The phage morphology was visualized with transmission electron microscopy. We characterized R4C in-depth with a genomic analysis and investigated the distribution of the R4C genome in different environments with a metagenomic recruitment analysis.(#br)RESULTS(#br)The double-stranded DNA genome of R4C consists of 36,291 bp with a high GC content of 66.75%. It has 49 genes with low DNA and protein homologies to those of other known phages. Morphological and phylogenetic analyses suggested that R4C is a novel member of the family Siphoviridae and is most closely related to phages in the genus Cronusvirus. However, unlike the Cronusvirus phages, R4C encodes an integrase, implying its ability to establish a lysogenic life cycle. A terminal analysis shows that, like that of λ phage, the R4C genome utilize the ’cohesive ends’ DNA-packaging mechanism. Significantly, homologues of the R4C genes are more prevalent in coastal areas than in the open ocean.(#br)CONCLUSIONS(#br)Information about this newly discovered phage extends our understanding of bacteriophage diversity, evolution, and their roles in different environments

    Impacts of Freshwater and Seawater Mixing on the Production and Decay of Virioplankton in a Subtropical Estuary

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    Abstract(#br)Virioplankton is an important component of the aquatic ecosystem and plays multiple ecological and biogeochemical roles. Although the spatial and temporal distributions and dynamics of virioplankton have been well investigated in riverine and marine environments, little is known about the dynamics and environmental controlling mechanisms of virioplankton in estuaries. In this study, viral abundance, production and decay were examined in the Pearl River Estuary (PRE), one of the largest estuaries in China. The influences of freshwater and seawater mixing on viral ecological dynamics were evaluated with several cross-transplant experiments. In PRE, viral abundance, production and decay rates varied from 2.72 ± 0.09 to 27.5 ± 1.07 × 10 6 viruses ml −1 , 7.98 ± 2.33 to 16.27 ±..

    Ambient outdoor air pollutants and sex ratio of singletons born after in vitro fertilization: the effect of single blastocyst transfer.

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    OBJECTIVE(#br)To evaluate the impact of air pollution on the sex ratio in singletons after IVF treatment and to evaluate the influence of the number of and the developmental stage of transferred embryos on the sex ratio.(#br)DESIGN(#br)Retrospective cohort study.(#br)SETTING(#br)University-affiliated IVF unit.(#br)PATIENT(S)(#br)A total of 7,004 singletons born after fresh transfer or frozen-thawed embryo transfer (FET) between January 2013 and December 2017.(#br)INTERVENTION(S)(#br)None.(#br)MAIN OUTCOME MEASURE(S)(#br)Male-to-female ratio in live-born singletons.(#br)RESULT(S)(#br)The estimated medians (interquartile range) of particle matter (PM)10, PM2.5, CO, NO2, O3, and SO2 at the IVF site were 51.4 (39.5-64.6), 27.7 (20.7-37.4), 0.62 (0.5-0.72), 32.5 (25.4-40.1), 79.6 (63.3-96.6), and 11.9 (9.3-15.9) μg/m3, respectively. Multivariate analysis indicated that SO2 was the only pollutant clearly associated with sex ratio. In singletons from single blastocyst transfer (SBT), as indicated by the generalized additive model, the SO2 concentration and sex ratio showed an inverted-U-shape association. In singletons after non-SBT, a monotonic decreasing in the sex ratio was observed with increased SO2 concentration. Compared with the referent category (SO2 < 7.57 μg/m3), the sex ratio at the 5th decile of SO2 (10.81-11.94 μg/m3) was increased by 2.1-fold (95% confidence interval [CI], 1.3-3.14) after adjusting covariates. In singletons born from non-SBT, the sex ratio significantly decreased only in the 9th (odds ratio = 0.69; 95% CI, 0.53-0.90) and 10th (OR = 0.74, 95% CI, 0.56-0.98) deciles.(#br)CONCLUSION(S)(#br)Low concentrations of SO2 showed an association with increased sex ratio in singletons of SBT, while in singletons born from another ET system the sex ratios did not show an association at low concentrations of SO2

    Active and diverse viruses persist in the deep sub-seafloor sediments over thousands of years

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    Viruses are ubiquitous and cause significant mortality in marine bacterial and archaeal communities. Little is known about the role of viruses in the sub-seafloor biosphere, which hosts a large fraction of all microbes on Earth. We quantified and characterized viruses in sediments from the Baltic Sea. The results show that the Baltic Sea sub-seafloor biosphere harbors highly abundant viruses with densities up to 1.8 × 1010 viruses cm−3. High potential viral production down to 37 meters below seafloor in ca. 6000-years-old sediments and infected prokaryotic cells visible by transmission electron microscopy demonstrate active viral infection. Morphological and molecular data indicate that the highly diverse community of viruses includes both allochthonous input from the overlying seawater and autochthonous production. The detection of cyanophage-like sequences showed that viruses of phototrophic hosts may persist in marine sediments for thousands of years. Our results imply that viruses influence sub-seafloor microbial community dynamics and thereby affect biogeochemical processes in the sub-seafloor biosphere

    Precore Mutation of Hepatitis B Virus May Contribute to Hepatocellular Carcinoma Risk: Evidence from an Updated Meta-Analysis

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    BACKGROUND: Studies focused on the correlation of mutations in the genome of Hepatitis B Virus (HBV) like Pre-S mutation, Basal Core promoter (BCP), Enhancer II (EnhII), especially Precore mutation, with the risk of hepatocellular carcinoma (HCC) have triggered stiff controversies. With an increasing number of studies in this field recently, we conducted this meta-analysis to appraise the correlations. METHODS: We searched the commonly used databases both in English and Chinese till February 1(st), 2012. Meta-analysis was performed in fixed/random-effects models using STATA 10.0. Publication bias was examined through Egger's test and Begg's funnel plot. RESULTS: In total, 85 case-control studies were included involving 16745 HBV-infected patients, of whom 5781 had HCC. Statistically significant correlations were observed in Precore mutation G1896A (OR = 1.46, 95% confidence interval [CI] = 1.15-1.85, P(OR) = 0.002), G1899A (OR = 3.13, 95%CI = 2.38-4.13, P(OR)<0.001) and Pre-S mutation especially Pre-S1 deletion (OR = 2.94, 95%CI = 2.22 to 3.89) and Pre-S2 deletion (OR = 3.02, 95%CI = 2.03 to 4.50). Similar correlation existed between BCP double mutation A1762T/G1764A, T1753V, C1653T and HCC. In subgroup analysis, the Asians, genotype C or HBeAg positive patients with certain above mutations may be more susceptible to HCC. Besides, the mutations like G1896A and BCP double mutation may be associated with the progression of the liver diseases. CONCLUSIONS: Precore mutation G1896A, G1899A, deletions in Pre-S region as well as the other commonly seen mutations correlated with the increased risk of HCC, especially in Asians and may predict the progression of the liver disease

    Semi-groupe de Lie associé à un cône symétrique

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    Volcanic arcs are the surface expression of magmatic systems that result from the subduction of mostly oceanic lithosphere at convergent plate boundaries. Arcs with a submarine component include intraoceanic arcs and island arcs that span almost 22,000 km on Earth\u27s surface, the vast majority of which are located in the Pacific region. Hydrothermal systems hosted by submarine arc volcanoes commonly contain a large component of magmatic fluid. This magmatic-hydrothermal signature, coupled with the shallow water depths of arc volcanoes and their high volatile contents, strongly influences the chemistry of the fluids and resulting mineralization and likely has important consequences for the biota associated with these systems. The high metal contents and very acidic fluids in these hydrothermal systems are thought to be important analogs to numerous porphyry copper and epithermal gold deposits mined today on land
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