Laminaria japonica Extract, an Inhibitor of Clavibater michiganense Subsp. Sepedonicum

Insights into enterovirus a-71 antiviral development: from natural sources to synthetic nanoparticles

Enteroviruses are pathogens responsible for several diseases, being enterovirus A71 (EVA71) the second leading cause of hand, foot, and mouth disease (HFMD), especially in Asia-Pacific countries. HFMD is mostly common in infants and children, with mild symptoms. However, the disease can result in severe nervous system disorders in children as well as in immunosuppressed adults. The virus is highly contagious, and its transmission occurs via fecal-oral, oropharyngeal secretions, and fomites. The EVA71 burdens the healthy systems and economies around the world, however, up to date, there is no antiviral approved to treat infected individuals and the existent vaccines are not available or approved to be used worldwide. In this context, an extensive literature research was conducted to describe and summarize the recent advances in natural and/or synthetic compounds with antiviral activity against EVA71. The summarized data presented here might simply encourage the future studies in EVA71 antiviral development, by encouraging further research encompassing these compounds or even the application of the techniques and technologies to improve or produce new antiviral molecules.

A review of volatile compounds in edible macroalgae

Seaweeds (green algae, red algae and brown algae) are rich in nutrients, and incorporating algae into the human diet can provide important health benefits. However, consumer acceptance of food is closely related to its flavor, and in this respect, volatile compounds are key factors. This article reviews the extraction methods and composition of volatile compounds from Ulva prolifera, Ulva lactuca, Sargassum spp. and economically valuable cultured seaweeds such as Undaria pinnatifida, Laminaria japonica, Neopyropia haitanensis and Neopyropia yezoensis. Research found that the volatile compounds of the above seaweeds were composed mainly of aldehydes, ketones, alcohols, hydrocarbons, esters, acids, sulfur compounds, furans and small amounts of other compounds. Volatile compounds such as benzaldehyde, 2-octenal, octanal, β-ionone and 8-heptadecene have been identified in several macroalgae. This review argues that more research on the volatile flavor compounds of edible macroalgae is required. Such research could aid new product development or widen applications of these seaweeds in the food or beverage sectors.

Bioinspired nanocoatings for biofouling prevention by photocatalytic redox reactions

Aquaculture is a billion dollar industry and biofouling of aquaculture installations has heavy economic penalties. The natural antifouling (AF) defence mechanism of some seaweed that inhibits biofouling by production of reactive oxygen species (ROS) inspired us to mimic this process by fabricating ZnO photocatalytic nanocoating. AF activity of fishing nets modified with ZnO nanocoating was compared with uncoated nets (control) and nets painted with copper-based AF paint. One month experiment in tropical waters showed that nanocoatings reduce abundances of microfouling organisms by 3-fold compared to the control and had higher antifouling performance over AF paint. Metagenomic analysis of prokaryotic and eukaryotic fouling organisms using next generation sequencing platform proved that nanocoatings compared to AF paint were not selectively enriching communities with the resistant and pathogenic species. The proposed bio-inspired nanocoating is an important contribution towards environmentally friendly AF technologies for aquaculture.

Self-decontaminating photocatalytic zinc oxide nanorod coatings for prevention of marine microfouling: a mesocosm study

The antifouling (AF) properties of zinc oxide (ZnO) nanorod coated glass substrata were investigated in an out-door mesocosm experiment under natural sunlight (14:10 light: dark photoperiod) over a period of five days. The total bacterial density (a six-fold reduction) and viability (a three-fold reduction) was significantly reduced by nanocoatings in the presence of sunlight. In the absence of sunlight, coated and control substrata were colonized equally by bacteria. MiSeq Illumina sequencing of 16S rRNA genes revealed distinct bacterial communities on the nanocoated and control substrata in the presence and absence of light. Diatom communities also varied on nanocoated substrata in the presence and the absence of light. The observed AF activity of the ZnO nanocoatings is attributed to the formation of reactive oxygen species (ROS) through photocatalysis in the presence of sunlight. These nanocoatings are a significant step towards the production of an environmentally friendly AF coating that utilizes a sustainable supply of sunlight.

Production of a compound against methicillin resistant Staphylococcus aureus (MRSA) from Streptomyces rubrolavendulae ICN3 & its evaluation in zebrafish embryos

BACKGROUND & OBJECTIVES

Antibiotic resistance in pathogens has become a serious problem worldwide. Therefore, the search for new antibiotics for drug resistanct pathogens is an important endeavor. The present study deals with the production of anti-methicillin resistant Staphylococcus aureus (MRSA) potential of Streptomyces rubrolavendulae ICN3 and evaluation of anti-MRSA compound in zebrafish embryos.

METHODS

The antibiotic production from S. rubrolavendulae ICN3 was optimized in solid state fermentation and extracted. The antagonistic activity was confirmed against MRSA and purified in silica gel column and reverse phase--HPLC with an absorption maximum at 215 nm. Minimal inhibitory concentration of the compound was determined by broth microdilution method. Zebrafish embryos were used to evaluate the extract/compound for its minimal inhibition studies, influences on heart beat rates, haematopoietic blood cell count and lethal dose values.

RESULTS

Streptomyces rubrolavendulae ICN3 showed potent antagonistic activity against MRSA with a zone of 42 mm. The minimum inhibitory concentration was calculated as 500 μg/ml of the crude extract and the purified C23 exhibited 2.5 μg/ml in in vitro assay. The LC 50 value of the anti MRSA compound C23 was calculated as 60.49 μg/ml and the MRSA treated embryos survived in the presence of purified compound C23 at a dose of 10 μg/ml.

INTERPRETATION & CONCLUSIONS

Our results suggested that the compound was potent with less toxic effects in zebrafish embryonic model system for MRSA infection. Further structural evaluation and analysis in higher mammalian model system may lead to a novel drug candidate for drug resistant Staphylococcus aureus.