Yang Xiao

Determination of albendazole and metabolites in silkworm Bombyx mori hemolymph by ultrafast liquid chromatography tandem triple quadrupole mass spectrometry.

Albendazole is a broad-spectrum parasiticide with high effectiveness and low host toxicity. No method is currently available for measuring albendazole and its metabolites in silkworm hemolymph. This study describes a rapid, selective, sensitive, synchronous and reliable detection method for albendazole and its metabolites in silkworm hemolymph using ultrafast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-MS/MS). The method is liquid-liquid extraction followed by UFLC separation and quantification in an MS/MS system with positive electrospray ionization in multiple reaction monitoring mode. Precursor-to-product ion transitions were monitored at 266.100 to 234.100 for albendazole (ABZ), 282.200 to 208.100 for albendazole sulfoxide (ABZSO), 298.200 to 159.100 for albendazole sulfone (ABZSO2) and 240.200 to 133.100 for albendazole amino sulfone (ABZSO2-NH2). Calibration curves had good linearities with R2 of 0.9905–0.9972. Limits of quantitation (LOQs) were 1.32 ng/mL for ABZ, 16.67 ng/mL for ABZSO, 0.76 ng/mL for ABZSO2 and 5.94 ng/mL for ABZSO2-NH2. Recoveries were 93.12%–103.83% for ABZ, 66.51%–108.51% for ABZSO, 96.85%–105.6% for ABZSO2 and 96.46%–106.14% for ABZSO2-NH2, (RSDs <8%). Accuracy, precision and stability tests showed acceptable variation in quality control (QC) samples. This analytical method successfully determined albendazole and its metabolites in silkworm hemolymph in a pharmacokinetic study. The results of single-dose treatment suggested that the concentrations of ABZ, ABZSO and ABZSO2 increased and then fell, while ABZSO2-NH2 level was low without obvious change. Different trends were observed for multi-dose treatment, with concentrations of ABZSO and ABZSO2 rising over time.

RNA-Seq Analyses for Two Silkworm Strains Reveals Insight into Their Susceptibility and Resistance to Beauveria bassiana Infection

The silkworm Bombyx mori is an economically important species. White muscardine caused by Beauveria bassiana is the main fungal disease in sericulture, and understanding the silkworm responses to B. bassiana infection is of particular interest. Herein, we investigated the molecular mechanisms underlying these responses in two silkworm strains Haoyue (HY, sensitive to B. bassiana) and Kang 8 (K8, resistant to B. bassiana) using an RNA-seq approach. For each strain, three biological replicates for immersion treatment, two replicates for injection treatment and three untreated controls were collected to generate 16 libraries for sequencing. Differentially expressed genes (DEGs) between treated samples and untreated controls, and between the two silkworm strains, were identified. DEGs and the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the two strains exhibited an obvious difference. Several genes encoding cuticle proteins, serine proteinase inhibitors (SPI) and antimicrobial peptides (AMP) and the drug metabolism pathway involved in toxin detoxification were considered to be related to the resistance of K8 to B. bassiana. These results revealed insight into the resistance and susceptibility of two silkworm strains against B. bassiana infection and provided a roadmap for silkworm molecular breeding to enhance its resistance to B. bassiana.

Fingerprint of Exhaust Gases and Database of Microbial Diversity During Silkworm Excrement Composting

ABSTRACT Composting can convert silkworm excrement (SE) into good fertilizer, but the popularization of this practice is greatly hampered due to the strong odor produced. Determining the gas pollutants, the potential native aerogenic microorganisms and deodorant microorganism communities will lay foundations for developing good strategies to deal with malodor pollution from SE composting. This study qualitatively and quantitatively analyzed the exhaust gas and the microbial diversity. With a combination of solid-phase micro-extraction-gas chromatography tandem mass spectrometry technology and other methods of Chinese national standards, 43 odor pollutants from SE composting were identified and quantified. Ammonia, sulfur dioxide and hydrogen sulfide were the three major pollutants among the volatile inorganic compounds, with concentrations far exceeding the permissible standards for workplaces in China. 5-Ethyl-2,2,3-trimethyl-heptane, 2,2,4,6,6-5-methyl-heptane and 5-isobutyl-nonane accounted for 46.58% of volatile organic compounds. Using analysis of ribosome DNA sequences with Illumina Miseq PE 2 * 250, a next generation high-throughput sequencing technology, more than 694 bacteria (and actinomycetes) and more than 136 fungi were annotated, including groups of native aerogenic microorganisms and deodorant microorganisms. This study indicated a serious malodor problem and abundant microorganisms from SE composting and provided basic data not only for odor pollution control but also for future functional microorganism studies.

Characterization and Sequence Analysis of Potential Biofertilizer and Biocontrol Agent Bacillus subtilis Strain SEM-9 from Silkworm Excrement

Fusarium wilt is a devastating soil-borne disease caused mainly by highly host-specific formae speciales of Fusarium oxysporum. Antagonistic microorganisms play a very important role in Fusarium wilt control, and the isolation of potential biocontrol strains is becoming more and more important. We isolated a bacterial strain (SEM-9) from the high-temperature stage of silkworm excrement composting, which had a marked ability to solubilize phosphorus, promote the growth and increase the yield of the small Chinese cabbage, and which also exhibited considerable antagonistic effect towards Fusarium sambucinum and other fungi. The result of physiological and biochemical analyses, as well as genome sequencing, showed that SEM-9 was a strain of Bacillus subtilis. Through genome annotation and analysis, it was found that SEM-9 contained genes related to the regulation of biofilm formation, which may play an important role in colonization, and gene clusters encoding the biosynthesis of antimicrobials, such as surfactin, bacilysin, fengycin, and subtilosin-A. The production of such antifungal compounds may constitute the basis of the mode-of-action of SEM-9 against Fusarium spp. These data suggested that the SEM-9 strain has potential as both a biofertilizer and a biocontrol agent, with the potential to manage Fusarium wilt disease in crops.