Applying meta-data of soybean grain in origin trace and quarantine inspection.

Soybean and derived products are among the most important food for both humans and animals. China is the world's largest importer of soybeans, with more than 100 million tons of annual imports, mainly from the United States of America (US), Brazil, and Argentina. However, there have been limited studies on the microbiota associated with imported soybean grains. Here, we reveal the soybean microbiota using amplicon sequencing based on samples from four countries on three continents of North America (US), South America (Argentina, Brazil), and Asia (China). Our results showed that the soybean-associated microbiota from different continents significantly separated, presenting strong geographic variations. The core microbial taxa and geographically specified taxa were defined, with Alternaria, Enterobacter, Plectosphaerella, Stenotrophomanas, and Xeromyces defined as the core microbiota for soybean from Asia; Amanita, Aspergillus, Fusarium, Nigrospora, Herbiconiux, Pseudomonas, Saccharopolyspora, and Schumannella from North America; and Bradyrhizobium, Colletotrichum, Filobasidium, Phialosimplex, Mycosphaerella, Septoria, Sphingomonas, and Weissalla, from South America. In addition, we build the Random Forest (RF) model to predict the source of imported soybean grains. We could accurately predict the original countries of imported soybean grains within the RF prediction models, with accuracies greater than 95 %. We constructed a database of soybean-related quarantine pathogens using full-length sequences of fungal ITS region and bacterial 16S rDNA region. Two phytopathogenic fungi, Diaporthe caulivora and Cladosporium cucumerinum, listed in the Chinese quarantine catalog, were intercepted through metabarcoding sequencing. The former was further confirmed using an available national standard protocol of qPCR diagnosis. In summary, our NGS-based approach revealed the microbiota associated with soybeans. It could provide comprehensive information and valuable method on the trace the origin of soybean and detection of quarantine pathogens at Customs and departments of inspection and quarantine.

Comparative transcriptomic analysis provides insights into transcription mechanisms of Vibrio parahaemolyticus T3SS during interaction with HeLa cells.

Vibrio parahaemolyticus is an important foodborne pathogenic bacterium that harbors the type III secretion system 1 (T3SS1) as an essential virulence factor. However, the pathogenesis and infection mechanism mediated by T3SS1 are not entirely clarified. Similar to previous studies on other T3SS-positive bacteria, the T3SS1 needle is a major extracellular component in V. parahaemolyticus. We recently showed that the needle gene-deletion mutant (ΔvscF) exhibited markedly decreased cytotoxicity and effector translocation during interaction with HeLa cells. To further elucidate the pathogenesis of T3SS1 during host cell infection, bacterial RNA was extracted from wild-type POR-1 and ΔvscF mutants under infected condition for comparative RNA sequencing analysis in HeLa cell. The results showed that 120 differentially expressed genes (DEGs) were identified in the ΔvscF-infected group. These encoded proteins of DEGs, such as VP2088, VP2089, and VP2091, were annotated as ABC transporter system, whereas VP0757, VP1123, and VP1289 may be new transcriptional regulators. In addition, the downregulation of T3SS1 had a positive influence on the expression of T3SS2. Moreover, the transcription of the basal body is unaffected by the needle, and there was a close relation among the tip, translocon, and needle, because bacterial adenylate cyclase two-hybrid system (BACTH system) assay indicated the interaction of VP1656, VP1670, VP1693, and VP1694 (VscF). This study provides insights into transcription mechanism of T3SS1 upon infecting HeLa cell, which is expected to better clarify the T3SS1 virulent mechanism.

Transcriptional analysis of four family 4 P450s in a Puerto Rico strain of Aedes aegypti (Diptera: Culicidae) compared with an Orlando strain and their possible functional roles in permethrin resistance.

A field strain of Aedes aegypti (L.) was collected from Puerto Rico in October 2008. Based on LD50 values by topical application, the Puerto Rico strain was 73-fold resistant to permethrin compared with a susceptible Orlando strain. In the presence of piperonyl butoxide, the resistance of Puerto Rico strain of Ae. aegypti was reduced to 15-fold, suggesting that cytochrome P450-mediated detoxification is involved in the resistance of the Puerto Rico strain to permethrin. To determine the cytochrome P450s that might play a role in the resistance to permethrin, the transcriptional levels of 164 cytochrome P450 genes in the Puerto Rico strain were compared with that in the Orlando strain. Of the 164 cytochrome P450s, 33 were significantly (P < 0.05) up-regulated, including cytochrome P450s in families four, six, and nine. Multiple studies have investigated the functionality of family six and nine cytochrome P450s, therefore, we focused on the up-regulated family 4 cytochrome P450s. To determine whether up-regulation of the four cytochrome P450s had any functional role in permethrin resistance, transgenic Drosophila melanogaster Meigen lines overexpressing the four family 4 P450 genes were generated, and their ability to survive exposure to permethrin was evaluated. When exposed to 5 microg per vial permethrin, transgenic D. melanogaster expressing CYP4D24, CYP4H29, CYP4J15v1, and CYP4H33 had a survival rate of 60.0 +/- 6.7, 29.0 +/- 4.4, 64.4 +/- 9.7, and 11.0 +/- 4.4%, respectively. However, none of the control flies survived the permethrin exposure at the same concentration. Similarly, none of the transgenic D. melanogaster expressing CYP4J15v1 or CYP4H33 ?5 survived when they were exposed to permethrin at 10 microg per vial. However, transgenic D. melanogaster expressing CYP4D24 and CYP4H29 had a survival rate of 37.8 +/- 4.4 and 2.2 +/- 2.2%, respectively. Taken together, our results suggest that CYP4D24 might play an important role in cytochrome P450-mediated resistance to permethrin.

Effects of chemical agent injections on genotoxicity of wastewater in a microfiltration-reverse osmosis membrane process for wastewater reuse.

With combined microfiltration (MF)/ultrafiltration (UF) and reverse osmosis (RO) process being widely used in municipal wastewater reclamation, RO concentrate with high level genotoxicity is becoming a potential risk to water environment. In this study, wastewater genotoxicity in a MF-RO process for municipal wastewater reclamation and also the effects of chemical agent injections were evaluated by SOS/umu genotoxicity test. The genotoxicity of RO concentrate ranged 500-559 µg 4-NQO (4-nitroquinoline-1-oxide)/L and 12-22 µg 4-NQO/mg DOC, was much higher than that of RO influent. Further research suggested that Kathon biocide was a key chemical agent associated with the genotoxicity increase. Kathon biocide used in RO system was highly genotoxic in vitro and Kathon biocide retained in RO system could contribute to a higher genotoxicity of RO concentrate. Hence, treatments for biocides before discharging are necessary. Chlorination of secondary effluent could significantly decrease the genotoxicity and increasing chlorine dosage could be an efficacious method to decrease the genotoxicity of RO concentrate. According to the result of the experiment, the dosage of chlorine in dual-membrane process could be set to about 2.5 mg Cl2/L. The effect of antiscalant (2-phosphomobutane-1,2,4-tricarboxylic acid) was also investigated; it turned out to have no effect on genotoxicity.