A Survey of Aflatoxin-Producing Aspergillus sp. from Peanut Field Soils in Four Agroecological Zones of China

Peanut pods are easily infected by aflatoxin-producing Aspergillus sp.ecies from field soil. To assess the aflatoxin-producing Aspergillus sp. in different peanut field soils, 344 aflatoxin-producing Aspergillus strains were isolated from 600 soil samples of four agroecological zones in China (the Southeast coastal zone (SEC), the Yangtze River zone (YZR), the Yellow River zone (YR) and the Northeast zone (NE)). Nearly 94.2% (324/344) of strains were A. flavus and 5.8% (20/344) of strains were A. parasiticus. YZR had the highest population density of Aspergillus sp. and positive rate of aflatoxin production in isolated strains (1039.3 cfu·g−1, 80.7%), the second was SEC (191.5 cfu·g−1, 48.7%), the third was YR (26.5 cfu·g−1, 22.7%), and the last was NE (2.4 cfu·g−1, 6.6%). The highest risk of AFB1 contamination on peanut was in YZR which had the largest number of AFB1 producing isolates in 1g soil, followed by SEC and YR, and the lowest was NE. The potential risk of AFB1 contamination in peanuts can increase with increasing population density and a positive rate of aflatoxin-producing Aspergillus sp. in field soils, suggesting that reducing aflatoxigenic Aspergillus sp. in field soils could prevent AFB1 contamination in peanuts

Is the rate of adverse reaction to rabies vaccine in China really as the public thinks?—based on a meta analysis

Objective To evaluate the rate of adverse reaction toward rabies vaccine in China from 2008 to 2019, explore its characteristics and to provide a scientific and objective basis for future policy decisions. Methods Literature on the rate of adverse reaction to rabies vaccine in China from 2008 to 2019 was retrieved and collected in CNKI, Wanfang, VIP databases, PubMed and Embase. A meta analysis was carried out then. Results Totally, 35 articles were included. The combined rate of adverse reaction to rabies vaccine was 5.6% (95% CI = 5.1% – 6.0%). Adverse reactions to rabies vaccine were 11.3% and 4.5% before and after 2011, 5.3% and 7.1% in the eastern and midwestern regions, 13.2%, 25.5% and 3.7% in the tertiary hospitals, secondary hospitals and primary medical institutions, respectively. And 13.3% were in the areas where the Changchun immortal vaccine was used. The combined rate of adverse reaction to rabies vaccine inoculated in Changsheng vaccine area was 5.1%. Conclusion After 2011, the rate of adverse reaction to rabies vaccine in China has decreased dramatically. The rate of adverse reaction to rabies vaccine in the midwestern regions is higher than the counterpart in the eastern regions. The primary medical institutions are lower than the counterpart in the tertiary and secondary hospitals

Inhibitory effect of essential oils on Aspergillus ochraceus growth and ochratoxin A production.

Ochratoxin A (OTA) is a mycotoxin which is a common contaminant in grains during storage. Aspergillus ochraceus is the most common producer of OTA. Essential oils play a crucial role as a biocontrol in the reduction of fungal contamination. Essential oils namely natural cinnamaldehyde, cinnamon oil, synthetic cinnamaldehyde, Litsea citrate oil, citral, eugenol, peppermint, eucalyptus, anise and camphor oils, were tested for their efficacy against A. ochraceus growth and OTA production by fumigation and contact assays. Natural cinnamaldehyde proved to be the most effective against A. ochraceus when compared to other oils. Complete fungal growth inhibition was obtained at 150-250 µL/L with fumigation and 250-500 µL/L with contact assays for cinnamon oil, natural and synthetic cinnamaldehyde, L. citrate oil and citral. Essential oils had an impact on the ergosterol biosynthesis and OTA production. Complete inhibition of ergosterol biosynthesis was observed at ≥ 100 µg/mL of natural cinnamaldehyde and at 200 µg/mL of citral, but total inhibition was not observed at 200 µg/mL of eugenol. But, citral and eugenol could inhibit the OTA production at ≥ 75 µg/mL and ≥ 150 µg/mL respectively, while natural cinnamaldehyde couldn't fully inhibit OTA production at ≤ 200 µg/mL. The inhibition of OTA by natural cinnamaldehyde is mainly due to the reduction in fungal biomass. However, citral and eugenol could significant inhibit the OTA biosynthetic pathway. Also, we observed that cinnamaldehyde was converted to cinnamic alcohol by A. ochraceus, suggesting that the antimicrobial activity of cinnamaldehyde was mainly attributed to its carbonyl aldehyde group. The study concludes that natural cinnamaldehyde, citral and eugenol could be potential biocontrol agents against OTA contamination in storage grains

BSMV-based miR159a silencing using the STTM approach in wheat.

<p>(<b>A</b>) Diagrammatic representation of STTM159a structure. (<b>B</b>) Semiquantitative RT-PCR assays detection of STTM159a structure expression in wheat infected with BSMV-EV and with BSMV-STTM159a. CP, coat protein of BSMV. (<b>C</b>) The 4^th leaves of wheat infected with BSMV-EV (left) and with BSMV-STTM159a (right) were photographed at 20 dpi. (<b>D</b>) Stem-loop RT-PCR together with real-time qPCR detection of mature miR159a relative transcript level in wheat infected with BSMV-EV and with BSMV-STTM159a. Error bars represented SE of three representing experiments from four replicates. (<b>E</b>) Real-time RT-PCR analysis of mRNA levels of miR159a target <i>TaMYB3</i> in BSMV-EV control and plants expressing STTM159a structure. Error bars representing SE were calculated from three replicates.</p

Schematic diagram of integrating BSMV-γb vector and <i>AtIPS1</i>-based MIM or STTM sequences.

<p>Modified BSMV-γb vector (pCaBS-γ-LIC) was shown in this figure. <i>AtIPS1</i>-based MIM or STTM sequences can be cloned into pCaBS-γ-LIC derivatives by the LIC reaction. MIM structure contained an <i>AtIPS1</i> backbone, but the target mimic motif of AthmiR399 was changed to that of corresponding miRNAs. STTM structure contained two tandem target mimics separated by a 48 nt imperfect stem-loop linker as described [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126621#pone.0126621.ref016" target="_blank">16</a>].</p

BSMV-based miR3134a silencing using <i>AtISP1</i>-based miRNA target mimicry in wheat.

<p>(<b>A</b>) Diagrammatic representation of MIM3134a structure. (<b>B</b>) Semiquantitative RT-PCR assays detection of MIM3134a structure expression in wheat infected with BSMV-EV and with BSMV-MIM3134a. CP, coat protein of BSMV. (<b>C</b>) The 4^th leaves of wheat infected with BSMV-EV (left) and with BSMV-MIM3134a (right) were photographed at 20 dpi. (<b>D</b>) Stem-loop RT-PCR together with real-time qPCR detection of mature miR3134a relative transcript level in wheat infected with BSMV-EV and with BSMV-MIM3134a. Error bars represented SE of three representing experiments from four replicates. (<b>E</b>) Real-time RT-PCR analysis of mRNA levels of miR3134a target AK335430 in BSMV-EV control and plants expressing MIM3134a structure. Error bars representing SE were calculated from three replicates.</p

Simultaneous silencing of miR159a and miR3134a using the BSMV expressing STTM approach in wheat.

<p>(<b>A</b>) Diagrammatic representation of STTM159a/3134a structure. (<b>B</b>) Semiquantitative RT-PCR assays detection of STTM159a/3134a structure expression in wheat infected with BSMV-EV and with BSMV-STTM159a/3134a. CP, coat protein of BSMV. (<b>C</b>) The 4^th leaves of wheat infected with BSMV-EV (left) and with BSMV-STTM159a/3134a (right) were photographed at 20 dpi. (<b>D</b>) Stem-loop RT-PCR together with real-time qPCR detection of mature miR159a and miR3134a relative transcript level in wheat infected with BSMV-EV and with BSMV-STTM159a/3134a. Error bars represented SE of three representing experiments from four replicates. (<b>E</b>) Real-time RT-PCR analysis of mRNA levels of miR159a target <i>TaMYB3</i> and miR3134a target AK335430 in BSMV-EV control and plants expressing STTM159a/3134a structure. Error bars representing SE were calculated from three replicates.</p

BSMV-based miR159a silencing using <i>AtISP1</i>-based miRNA target mimicry in wheat.

<p>(<b>A</b>) Diagrammatic representation of MIM159a structure. (<b>B</b>) Semiquantitative RT-PCR assays detection of MIM159a structure expression in wheat infected with BSMV-EV and with BSMV-MIM159a. CP, coat protein of BSMV. (<b>C</b>) The 4^th leaves of wheat infected with BSMV-EV (left) and with BSMV-MIM159a (right) were photographed at 20 dpi. (<b>D</b>) Stem-loop RT-PCR together with real-time quantitative PCR (qPCR) detection of mature miR159a relative transcript level in wheat infected with BSMV-EV and with BSMV-MIM159a. Error bars represented standard error (SE) of three representing experiments from four replicates. (<b>E</b>) Real-time RT-PCR analysis of mRNA levels of miR159a target <i>TaMYB3</i> in BSMV-EV control and plants expressing MIM159a structure. Error bars representing SE were calculated from three replicates.</p

<i>Barley Stripe Mosaic Virus</i> (BSMV) Induced MicroRNA Silencing in Common Wheat (<i>Triticum aestivum L</i>.)

<div><p>MicroRNAs (miRNAs) play important roles in growth, development, and response to environmental changes in plants. Based on the whole-genome shotgun sequencing strategy, more and more wheat miRNAs have been annotated. Now, there is a need for an effective technology to analyse endogenous miRNAs function in wheat. We report here that the modified <i>barley stripe mosaic virus</i> (BSMV)-induced miRNAs silencing system can be utilized to silence miRNAs in wheat. BSMV-based miRNA silencing system is performed through BSMV-based expression of miRNA target mimics to suppress miR159a and miR3134a. The relative expression levels of mature miR159a and miR3134a decrease with increasing transcript levels of their target genes in wheat plants. In summary, the developed approach is effective in silencing endogenous miRNAs, thereby providing a powerful tool for biological function analyses of miRNA molecules in common wheat.</p></div

Functional Characterization of New Polyketide Synthase Genes Involved in Ochratoxin A Biosynthesis in Aspergillus Ochraceus fc-1

Ochratoxin A (OTA), a potentially carcinogenic mycotoxin which contaminates grains, is produced by several Aspergillus species. A comparative sequence analysis of the OTA-producing Aspergillus ochraceus fc-1 strain and other Aspergillus species was performed. Two new OTA-related polyketide synthase (PKS) (AoOTApks) genes were identified. The predicted amino acid sequence of AoOTApks-1 displayed high similarity to previously identified PKSs from OTA-producing A. carbonarius ITEM 5010 (67%; [PI] No. 173482) and A. niger CBS 513.88 (62%; XP_001397313). However, the predicted amino acid sequence of AoOTApks-2 displayed lower homology with A. niger CBS 513.88 (38%) and A. carbonarius ITEM 5010 (28%). A phylogenetic analysis of the β-ketosynthase and acyl-transferase domains of the AoOTApks proteins indicated that they shared a common origin with other OTA-producing species, such as A. carbonarius, A. niger, and A. westerdijkiae. A real-time reverse-transcription PCR analysis showed that the expression of AoOTApks-1 and -2 was positively correlated with the OTA concentration. The pks gene deleted mutants ∆AoOTApks-1 and ∆AoOTApks-2 produced nil and lesser OTA than the wild-type strain, respectively. Our study suggests that AoOTApks-1 could be involved in OTA biosynthesis, while AoOTApks-2 might be indirectly involved in OTA production