Search

Peste des petits ruminants virus (PPRV), a member of the family Paramyxoviridae, belongs to the genus Morbillivirus. It causes devastating viral diseases in small ruminants and has been rapidly spreading over various regions in Africa, the Middle East, and Asia. Although vaccination is thought to be an effective management strategy against PPR infections, the heat sensitivity of PPRV vaccines severely restricts their use in regions with hot climates. In this research, we studied the antiviral activities of ribavirin and aimed to understand the potential mechanisms of action of ribavirin in the African green monkey kidney cells (Vero cells). In brief, the adsorption, intrusion, replication, and release of PPRV, as well as the mRNA expression level of RNA-dependent RNA polymerase (RdRp), were significantly inhibited in the ribavirin-treated Vero cells compared to those in the PPRV-infected cells that were not treated with ribavirin. Additionally, ribavirin has potential as an antiviral drug against PPRV, and its antiviral activity is mediated by the Janus kinase signal transducer and activator of transcription (JAK/STAT) and PI3K/AKT pathways.

Picoplankton abundance and biomass in Sanggou Bay, China, were investigated in 4 successive seasons (April, August and October 2011, January 2012). Different distribution patterns of picoplankton abundance and biomass were observed according to season and culture areas (bivalves or macroalgae). Synechococcus, picoeukaryotes and heterotrophic prokaryotes exhibited higher abundance and biomass in warm seasons (summer and autumn) than in cold seasons (spring and winter). Over all 4 seasons, picoplankton abundance was higher in the bivalve culture area than in the macroalgae culture area. Among picoplankton, picoeukaryotes contributed most to the carbon standing stock in summer and autumn. In spring and winter, the heterotrophic component biomass exceeded that of the autotrophic picoplankton. Picoeukaryotes were an important contributor (21-27%) to total phytoplankton carbon biomass in spring to autumn. In spring, heterotrophic prokaryote biomass accounted for more than 56% of total phytoplankton biomass, and even exceeded phytoplankton biomass at some stations. As revealed by multiple stepwise regression analysis, physicochemical factors and protist grazing were the most important variables that controlled picoplankton distribution and variation. The reduction in grazing pressure, as well as phosphorus release by bivalves, is likely to explain the higher abundance of picoplankton in the bivalve culture area of Sanggou Bay.

ABSTRACT The present study was carried out to investigate the influence of freezing-thawing cycles (0, 2, 4 and 6) on lipid oxidation and myowater contents and distribution. Nine replicates of chicken breast meat samples were used for each cycle. Lipid oxidation was determined by measuring peroxide value, and malondialdehyde (MDA) concentrations, which reflect thiobarbituric acid reactive substance (TBARS). Color was determined with a digital colorimeter. Muscle moisture contents were determined by drip loss and thawing loss, water holding capacity, and nuclear magnetic resonance (NMR). The results showed that, as the number of freeze-thaw cycles increased, meat redness decreased and MDA and peroxide values increased. Drip loss and thawing loss tended to decreasing as the number of freeze-thaw cycles increased. Water holding capacity also decreased as a function of increasing freeze-thaw cycles. NMR relaxometry profile showed freeze-thaw cycles change the water distribution of meat subjected to multiple freeze-thaw cycles. In conclusion, multiple freezing and thawing rate (6 cycles) increased lipid oxidation, decreased myowater, and impaired the color of chicken meat.

Feeding ratio and frequency have substantial effects on food digestion and assimilation in fish, yet few attempts have been made to determine their influences on the bioaccumulation of trace metals. In this study, juvenile Acanthopagrus schlegeli were exposed to either waterborne or dietary cadmium (Cd) at different feeding ratios (0, 2, or 4% body weight d-1 [BW d-1] under waterborne Cd exposure and 1, 2.5, or 4% BW d-1 under dietary Cd exposure) or feeding frequencies (1, 2 or 8 times d-1) for 5 wk. Under waterborne Cd exposure, the fish fed 0% BW d-1 or 8 times d-1 showed significantly lower growth rates and those fed 0% BW d-1 or 1 time d-1 exhibited higher Cd body burdens and Cd uptake rates compared to the other groups. The gut showed a significantly higher waterborne Cd uptake rate than the gills when fish were fasted or fed only 1 time d-1. These results suggest that starvation and low feeding frequency facilitate waterborne Cd uptake. Under dietary Cd exposure, the fish fed 4% BW d-1 or 2 times d-1 grew faster. Cd body burden and Cd assimilation were higher in fish fed 2.5% BW d-1 or 2 times d-1. Dietary Cd retention was positively correlated with feed efficiency, suggesting the utilization of Cd probably coincides with the essential nutrients in fish. Overall, this study demonstrates that different feeding strategies significantly influence waterborne and dietary Cd bioaccumulation in marine fish. Therefore, feeding conditions have to be considered carefully for managing trace metal contamination in marine fish farming.

Temperature and salinity are critical to the reproduction, growth, and survival of shellfish. We investigated the combined effects of temperature (15 °C, 20 °C, and 25 °C) and salinity [20, 30, and 40 practical salinity units (PSUs)] on the horse mussel Modiolus modiolus, which inhabits the northern Chinese coast. The specific growth rate of M. modiolus increased with salinity at a low temperature (15 °C). The interaction between temperature and salinity with respect to M. modiolus survival was significant (Two-Way ANOVA; p < 0.01). Across all temperatures tested, M. modiolus specimens kept at low salinity (20 PSU) had narrower gill filament lumens than those kept at moderate salinity (30 PSU); the gill filament lumens of specimens kept at high salinity (40 PSU) were wider than either of these. The combined effects of temperature and salinity on superoxide dismutase (SOD) activity, total antioxidant capacity (T-AOC), and glutathione peroxidase (GPx) activity in the gills of M. modiolus were significant (Two-Way ANOVA; p < 0.05). Our results suggested that temperature and salinity significantly affect the survival, gill morphology, and antioxidant capabilities of M. modiolus. Our findings not only enrich our knowledge of the interactions between temperature and salinity with respect to shellfish but also provide a framework for M. modiolus aquaculture development.

Heavy metal pollution has become an increasingly recognized threat to the aquatic environment. In response to heavy metal stresses, various terrestrial plants produce the hormone nitric oxide (NO), but minimal information is available about the role of NO in aquatic macrophytes under high zinc (Zn) stress. In this study, we measured physiochemical parameters in the leaves of Hydrilla verticillata exposed to Zn2+ (10 mg l-1) alone or combined with NO (supplied as sodium nitroprusside, SNP) for 1 d and 4 d. Excess Zn disturbed nutrient uptake and altered the redox status of the aquatic plants. NO application partially reversed negative impacts of Zn stress on the contents of photosynthetic pigments, malondialdehyde, nutrient concentration, ascorbic acid, and the activity of antioxidant enzymes. However, the metabolites of SNP did not have similar effects. After treatments for 4 d, plants were further cultured in a solution containing Zn2+ (10 mg l-1) for 10 d. NO application partially reversed Zn-induced negative effects in parameters such as nutrient uptake, antioxidant enzymatic activities, and biomass, as compared to treatments with Zn alone. These results indicate that NO supply could mitigate Zn stress in H. verticillata, as a defense mechanism of the plant against Zn toxicity.

The species composition and abundance of the planktonic Hyperiidea and their relationship with environmental factors (depth, temperature, salinity, dissolved oxygen, turbidity and chlorophyll a concentration) were analyzed based on 4 seasonal investigations in the Beibu Gulf between 2006 and 2007. Hyperiids were represented by 82 species, 5 of which had not previously been recorded in the South China Sea. The hyperiid communities were dominated by Lestrigonus bengalensis year-round, Hyperioides sibaginis was dominant in spring, summer and autumn, and Tullbergella cuspidata became dominant in spring. Both species richness and the Shannon-Wiener diversity index increased from north to south, and from nearshore to offshore. Biodiversity was higher in some regions where the water mass was strongly influenced by the open sea or the lower salinity water off the northern sea shelf. Results of partial correlation analysis showed that species richness was positively related to depth at all times, and negatively related to temperature only in summer and winter. TWINSPAN classification indicated that the Hyperiidea community was divided into 2 groups in spring and winter (a widely distributed group and a pelagic warm-water group), and 3 groups in summer and autumn. A clear distinction between euryhaline and pelagic species can be discerned, based on different geographical distributions of water masses.

Vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) have been widely used in the fields of tissue engineering and regenerative medicine to stimulate angiogenesis and bone formation. The goal of this study was to determine whether VEGF and BMP-2 are involved in the homing of bone marrow stem cells (BMSCs) for bone regeneration and to provide insights into their mechanism of action. The chemoattraction of BMSCs to VEGF and BMP-2 was analysed in vitro using a checkerboard assay. VEGF and BMP-2 stimulated the chemotaxis of BMSCs but not chemokinesis. In vivo, both VEGF and BMP-2 also have been confirmed to induce the homing of tail vein injected BMSCs to the site of silk scaffold subcutaneous implantation in nude mice. When the scaffolds were implanted in the rabbit skull defects, more SSEA+ mesenchymal stem cells were mobilised and homed to silk scaffolds containing VEGF and/or BMP-2. More importantly, autogenic BMSCs were reinjected via the ear vein after labelling with lenti-GFP, and the cells were detected to home to the defects and differentiate into endothelial cells and osteogenic cells induced by VEGF and BMP-2. Finally, perfusion with Microfil showed that initial angiogenesis was enhanced in tissue-engineered complexes containing VEGF. Observations based on µCT assay and histological study revealed that bone formation was accelerated on BMP-2-containing scaffolds. These findings support our hypothesis that the localised release of VEGF and BMP-2 promote bone regeneration, in part by facilitating the mobilisation of endogenous stem cells and directing the differentiation of these cells into endothelial and osteogenic lineages.

The purpose of this study was to investigate the effects of akermanite as compared to β-TCP on attachment, proliferation, and osteogenic differentiation of human periodontal ligament cells (hPDLCs). Scanning electron microscopy (SEM) and actin filament labeling were used to reveal attachment and growth of hPDLCs seeded on β-TCP and akermanite ceramic. Cell proliferation was tested by lactic acid production and MTT analysis, while osteogenic differentiation was assayed by alkaline phosphatase (ALP) expression and real-time polymerase chain reaction (PCR) analysis on markers of osteopontin (OPN), dentin matrix acidic phosphoprotein-1 (DMP-1), and osteocalcin (OCN), and further detected by enzyme-linked immunosorbent analysis (ELISA) analysis for OCN expression. Besides, the ions released from akermanite and their effect on hPDLCs was also measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES), MTT analysis, ALP expression and real-time PCR analysis. hPDLCs attached well on both ceramics, but showed better spreading on akermanite. hPDLCs proliferated more rapidly on akermanite than β-TCP. Importantly, osteogenic differentiation of hPDLCs was enhanced on akermanite compared to β-TCP. Besides, Ca, Mg and Si ions were released from akermanite, while only Ca ions were released from β-TCP. Moreover, more pronounced proliferation and higher osteogenic gene expression for hPDLCs cultured with akermanite extract were detected as compared to cells cultured on akermanite. Therefore, akermanite ceramic showed an enhanced effect on proliferation and osteogenic differentiation of hPDLCs, which might be attributed to the release of ions containing Ca, Mg and Si from the material. It is suggested that akermanite ceramics may serve as a potential material for periodontal bone regeneration.

In an increasingly globalized world, invasive species cause major human, financial, and environmental costs. A cosmopolitan pest of great concern is the cassava mealybug Phenacoccus manihoti (Hemiptera: Pseudococcidae), which invaded Asia in 2008. Following its arrival, P. manihoti inflicted measurable yield losses and a 27% drop in aggregate cassava production in Thailand. As Thailand is a vital exporter of cassava-derived commodities to China and supplies 36% of the world’s internationally-traded starch, yield shocks triggered price surges and structural changes in global starch trade. In 2009 a biological control agent was introduced in Asia-the host-specific parasitoid, Anagyrus lopezi (Hymenoptera: Encyrtidae). This parasitoid had previously controlled the cassava mealybug in Africa, and its introduction in Asia restored yield levels at a continent-wide scale. Trade network and price time-series analyses reveal how both mealybug-induced production loss and subsequent parasitoid-mediated yield recovery coincided with price fluctuations in futures and spot markets, with important cascading effects on globe-spanning trade networks of (cassava) starch and commodity substitutes. While our analyses may not imply causality, especially given the concurrent 2007–2011 food crises, our results do illuminate the important interconnections among subcomponents of the global commodity system. Our work underlines how ecologically-based tactics support resilience and safeguard primary productivity in (tropical) agro-ecosystems, which in turn help stabilize commodity markets in a similar way as pesticide-centered approaches. Yet, more importantly, (judiciously-implemented) biological control can deliver ample ‘hidden’ environmental and human-health benefits that are not captured by the prices of globally-traded commodities.

We present a method for accurate mid-infrared frequency measurements and stabilization to a near-infrared ultra-stable frequency reference, transmitted with a long-distance fibre link and continuously monitored against state-of-the-art atomic fountain clocks. As a first application, we measure the frequency of an OsO _4 rovibrational molecular line around 10 μ m with an uncertainty of 8 × 10 ^−13 . We also demonstrate the frequency stabilization of a mid-infrared laser with fractional stability better than 4 × 10 ^−14 at 1 s averaging time and a linewidth below 17 Hz. This new stabilization scheme gives us the ability to transfer frequency stability in the range of 10 ^−15 or even better, currently accessible in the near infrared or in the visible, to mid-infrared lasers in a wide frequency range.

ABSTRACT Newcastle disease is a highly contagious disease responsible for major outbreaks and considerable economic losses in the poultry industry in China. There is still little information available regarding gene characterization of the NDV, especially in ducks and pigeons. Therefore, the aim of this study was to investigate NDV isolated from ducks and pigeons in Hubei, China. In this study, three NDVs from ducks and pigeons were isolated between 2013 and 2015.The fusion protein (F) gene of the NDV isolates was sequenced and phylogenetically analyzed. The clinical signs and gross histopathological lesions were examined. Phylogenetic analysis of these strains indicated that all the sequences are classified as genotype II. The isolates shared a 112 G-R-Q-G-R-L 117motif at the F protein cleavage site, indicating that these three isolates strains are lentogenic. Necropsy and histopathology showed the typical pathological changes. It was concluded that commercial ducks and pigeons in Hubei province carry lentogenic NDV strains with regular genetic divergence, indicating that these species may act as the main reservoirs of NDV in poultry. Therefore, strategies and surveillance should be undertaken to reduce the risk of ND outbreaks.