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As one of the nearest and most dormant supermassive black holes (SMBHs), M31* provides a rare but promising opportunity for studying the physics of black hole accretion and feedback at the quiescent state. Previous Karl G. Jansky Very Large Array (VLA) observations with an arcsecond resolution have detected M31* as a compact radio source over centimeter wavelengths, but the steep radio spectrum suggests optically thin synchrotron radiation from an outflow driven by a hot accretion flow onto the SMBH. Aiming to probe the putative radio outflow, we conducted milliarcsecond-resolution very long baseline interferometric (VLBI) observations of M31* in 2016, primarily at 5 GHz and combining the Very Long Baseline Array, Tianma 65 m, and Shanghai 25 m radio telescopes. Despite the unprecedented simultaneous resolution and sensitivity achieved, no significant (≳3 σ) signal is detected at the putative position of M31* given an rms level of 5.9 μ Jy beam−1, thus ruling out a pointlike source with a peak flux density comparable to that (∼30 μ Jy beam−1) measured by the VLA observations taken in 2012. We disfavor the possibility that M31* has substantially faded since 2012, in view that a 2017 VLA observation successfully detected M31* at a historically high peak flux density (∼75 μ Jy beam−1 at 6 GHz). Instead, the nondetection of the VLBI observations is best interpreted as the arcsecond-scale core being resolved out at the milliarcsecond scale, suggesting an intrinsic size of M31* at 5 GHz larger than ∼300 times the Schwarzschild radius. Such extended radio emission may originate from a hot wind driven by the weakly accreting SMBH. [ABSTRACT FROM AUTHOR]

A systematic study was carried out on 638 wheat and paddy grains (including fresh and stored samples) collected in 2021 from Shanghai, China, to identify the major mycobiota and their toxigenic abilities. A total of 349 fungi, namely, 252 Fusarium, 53 Aspergillus, and 44 Alternaria, were characterized by morphological and molecular identification. Fusarium and Aspergillus were more frequently isolated in paddy with Fusarium sambucinum species complex and Aspergillus section flavi as the predominant species, respectively. The genus Alternaria was the most frequently isolated fungal species in wheat. The toxin-producing potentials of the identified fungi were further evaluated in vitro. Deoxynevalenol (DON) was produced by 34.5% of Fusarium isolates and zearalenone (ZEN) was produced by 47.6% of them, and one isolate also processed the abilities for fumonisin B1 (FB1), B2 (FB2), and B3 (FB3) productions. Aflatoxin B1 (AFB1), B2 (AFB2), and G1 (AFG1) were only generated by Aspergillus section flavi, with the production rate of 65.5%, 27.6%, and 13.8%, respectively. Alternariol (AOH) was the most prevalent Alternaria toxin, which could be produced by 95.5% of the isolates, followed by alternariol monomethyl ether (AME) (72.7%), altenuene (ALT) (52.3%), tenuazonic acid (TeA) (45.5%), tentoxin (TEN) (29.5%), and altenusin (ALS) (4.5%). A combinational analysis of mycobiota and toxigenic ability allowed us to provide comprehensive information about the production mechanisms of mycotoxins in wheat and paddy in a specific geographic area, and will be helpful for developing efficient prevention and control programs. [ABSTRACT FROM AUTHOR]

Campylobacter species are zoonotic pathogens, as well as the prevalent cause of foodborne bacterial gastroenteritis. The spread of antimicrobial-resistant strains poses a serious threat to global public health and attracts attention worldwide, but information about clinical Campylobacter is relatively limited compared to isolates from food and animals. The current study illustrated the prevalence and antimicrobial resistance profiles of Campylobacter jejuni and Campylobacter coli isolates collected from a consecutive surveillance program between 2012 and 2019 in Shanghai, China, using antimicrobial susceptibility testing and whole-genome sequencing. Among the 891 Campylobacter strains (761 C. jejuni and 130 C. coli) isolates collected, high portions above 90% of resistance to ciprofloxacin, nalidixic acid, and tetracycline were observed for both C. jejuni and C. coli. The most common MDR profiles represented by C. jejuni and C. coli were combination of ciprofloxacin, tetracycline, florfenicol and nalidixic acid (5.39%), and azithromycin, ciprofloxacin, erythromycin, gentamicin, tetracycline, clindamycin, nalidixic acid (28.46%), respectively. The erythromycin resistance of C. coli (59.23%) is higher than C. jejuni (2.50%). A total of 76 erythromycin resistant isolates (16 C. jejuni and 60 C. coli) were sequenced using Illumina platform for determining the genotypes, antimicrobial resistance patterns and phylogeny analysis. Multilocus sequence typing (MLST) analysis showed a high genetic diversity with 47 sequence types (STs), including 4 novel alleles and 12 new STs. The most abundant clonal complexes (CCs) were CC-403 (31.25%) and CC-828 (88.33%) for C. jejuni and C. coli, respectively. Among the 76 erythromycin-resistant isolates, mutation A2075G in 23S rRNA and erm(B) gene were detected in 53.95 and 39.47%, respectively. The erm(B) gene was identified exclusively in 30 C. coli isolates. All these erm(B) positive isolates were multi-drug resistant. Furthermore, comparison of the erm(B)-carrying isolates of multiple sources worldwide demonstrated the possibility of zoonotic transmission of erm(B) in Campylobacter. These findings highlight the importance of continuous surveillance of erythromycin resistance dissemination in Campylobacter which may compromise the effectiveness of antimicrobial therapy. [ABSTRACT FROM AUTHOR]

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