Nematode-trapping fungi are “carnivorous” and attack their hosts using specialized trapping devices. The morphological development of these traps is the key indicator of their switch from saprophytic to predacious lifestyles. Here, the genome of the nematode-trapping fungus Arthrobotrys oligospora Fres. (ATCC24927) was reported. The genome contains 40.07 Mb assembled sequence with 11,479 predicted genes. Comparative analysis showed that A. oligospora shared many more genes with pathogenic fungi than with non-pathogenic fungi. Specifically, compared to several sequenced ascomycete fungi, the A. oligospora genome has a larger number of pathogenicity-related genes in the subtilisin, cellulase, cellobiohydrolase, and pectinesterase gene families. Searching against the pathogen-host interaction gene database identified 398 homologous genes involved in pathogenicity in other fungi. The analysis of repetitive sequences provided evidence for repeat-induced point mutations in A. oligospora. Proteomic and quantitative PCR (qPCR) analyses revealed that 90 genes were significantly up-regulated at the early stage of trap-formation by nematode extracts and most of these genes were involved in translation, amino acid metabolism, carbohydrate metabolism, cell wall and membrane biogenesis. Based on the combined genomic, proteomic and qPCR data, a model for the formation of nematode trapping device in this fungus was proposed. In this model, multiple fungal signal transduction pathways are activated by its nematode prey to further regulate downstream genes associated with diverse cellular processes such as energy metabolism, biosynthesis of the cell wall and adhesive proteins, cell division, glycerol accumulation and peroxisome biogenesis. This study will facilitate the identification of pathogenicity-related genes and provide a broad foundation for understanding the molecular and evolutionary mechanisms underlying fungi-nematodes interactions.

This is a repository copy of Novel colorimetric films based on starch/polyvinyl alcohol incorporated with roselle anthocyanins for fish freshness monitoring.

Plant-parasitic nematodes cause significant damage to a broad range of vegetables and agricultural crops throughout the world. As the natural enemies of nematodes, nematophagous microorganisms offer a promising approach to control the nematode pests. Some of these microorganisms produce traps to capture and kill the worms from the outside. Others act as internal parasites to produce toxins and virulence factors to kill the nematodes from within. Understanding the molecular basis of microbe-nematode interactions provides crucial insights for developing effective biological control agents against plant-parasitic nematodes. Here, we review recent advances in our understanding of the interactions between nematodes and nematophagous microorganisms, with a focus on the molecular mechanisms by which nematophagous microorganisms infect nematodes and on the nematode defense against pathogenic attacks. We conclude by discussing several key areas for future research and development, including potential approaches to apply our recent understandings to develop effective biocontrol strategies.

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This is a repository copy of Preparation of an intelligent pH film based on biodegradable polymers and roselle anthocyanins for monitoring pork freshness.

Understanding the mechanisms of host-pathogen interaction can provide crucial information for successfully manipulating their relationships. Because of its genetic background and practical advantages over vertebrate model systems, the nematode Caenorhabditis elegans model has become an attractive host for studying microbial pathogenesis. Here we report a "Trojan horse" mechanism of bacterial pathogenesis against nematodes. We show that the bacterium Bacillus nematocida B16 lures nematodes by emitting potent volatile organic compounds that are much more attractive to worms than those from ordinary dietary bacteria. Seventeen B. nematocidaattractant volatile organic compounds are identified, and seven are individually confirmed to lure nematodes. Once the bacteria enter the intestine of nematodes, they secrete two proteases with broad substrate ranges but preferentially target essential intestinal proteins, leading to nematode death. This Trojan horse pattern of bacterium-nematode interaction enriches our understanding of microbial pathogenesis.Bacillus nematocida | Caenorhabditis elegans | chemotaxis | pathogen-host interaction | virulence protease M ost model organisms, such as the yeast Saccharomyces cerevisiae, the slime mold Dictyostelium discoideum, the mouseear cress plant Arabidopsis thaliana, the common fruit fly Drosophila melanogaster, and the nematode Caenorhabditis elegans, can be infected by microbes, including certain human-pathogenic bacteria (1). For several reasons, C. elegans is an attractive model organism to study host-pathogen interactions: It has simple growth requirements, a short generation time, a well-defined developmental process with invariant cell lineage sorting, a fully sequenced genome, and a suite of well-established genetic tools (2). Using C. elegans as a model, scientists in the last few years have identified a diversity of physical, chemical, and biochemical features involved in microbial pathogenesis (3). For example, Brevibacillus laterosporus secretes extracellular proteases that damage nematode cuticle, and Bacillus thuringiensis produces toxic crystal proteins that disrupt host cellular functions (4, 5). The common humanpathogenic bacterium Pseudomonas aeruginosa kills C. elegans with quorum-sensing controlled-virulence factors (6) and cyanide (7). Several other human pathogens such as the Gram-negative bacteria Burkholderia pseudomallei and Serratia marcescens and the Gram-positive bacteria Enterococcus faecalis, Streptococcus pyogenes, and Staphylococcus aureus also are reported to have nematoxic activities via a neuromuscular endotoxin, a cytolysin, two extracellular proteases (gelatinase and serine protease), and several other toxins (8-12). In S. aureus, several virulence determinants known to be important in mammalian pathogenesis, including the quorum-sensing global virulence regulatory system agr and the global virulence regulator sarA, the alternative sigma factor B, α-hemolysin, and the V8 serine protease, are all required for full pathogenicity against nematode...

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An edible and pH-sensitive film combined with electrochemical writing was developed using gelatin, gellan gum and red radish anthocyanin extract for intelligent food packaging applications. The composite film displays orange red-to-yellow color change over the pH range 2-12. The tensile strength, ductility, and barrier response of the films to UV light and oxygen improved with the increase of red radish anthocyanin concentration. Multicolor patterns were successfully drawn on the film using an electrochemical writing method. The composite films acted as gas sensors which presented visible color changes in the presence of milk and fish spoilage, while the written patterns were well preserved. Accordingly, this composite film with written patterns could be an easy-to-use indicator with great potential for monitoring food spoilage as part of an intelligent packaging system.