Characterization of an International High-Risk Escherichia coli ST410 Clone Coproducing NDM-5 and OXA-181 in a Food Market in China.

During a 2020 routine epidemiological investigation of carbapenem-resistant Enterobacterales at a local food market in Guangzhou, China, two Escherichia coli ST410 isolates coproducing NDM-5 and OXA-181 were obtained from environmental samples. Antimicrobial susceptibility testing, whole-genome sequencing, and conjugation assays were applied to identify their resistance phenotypes, phylogenetic relatedness, and genetic characteristics. Phylogenetic analysis showed that the two isolates were clonally related with only one core-genome single-nucleotide polymorphism (SNP) difference and clustered into a branch with 87 E. coli ST410 isolates deposited in GenBank. These 89 ST410 isolates were closely related (≤51 SNPs), and most were from humans in Southeast Asian countries (n = 47). A Vietnamese clinical isolate collected in 2017 showed the strongest epidemiological link (seven SNPs) to the two ST410 isolates detected in this study. Complete-genome analysis revealed that the carbapenem resistance determinants blaNDM-5 and blaOXA-181 were located on an IncF1:A1:B49-IncQ1 plasmid and IncX3 plasmid, respectively. Conjugation experiments confirmed that the IncX3 plasmid was self-transmissible while the IncF1:A1:B49-IncQ1 plasmid was nonconjugative. BLASTn analysis indicated that the two plasmids showed high similarity to other blaNDM-5-bearing IncF1:A1:B49-IncQ1 and blaOXA-181-bearing IncX3 plasmids from other countries. Altogether, the high similarity of the core genomes and plasmids between the ST410 isolates found in this study and those human source isolates from foreign countries suggested the clonal spread of E. coli ST410 strains and horizontal transmission of blaOXA-181-bearing IncX3 plasmids across Southeast Asian countries. Stringent sanitary management of food markets is important to prevent the dissemination of high-risk clones to the public. IMPORTANCE This is the first report of an Escherichia coli ST410 clone that coproduces NDM-5 and OXA-181 in China. The high similarity of the core genomes and plasmids between the ST410 isolates characterized in this study and human source isolates from foreign countries strongly suggests that this ST410 lineage is an international high-risk clone, highlighting the need for continuous global surveillance of ST410 clones.

Clonal spread of Escherichia coli O101: H9-ST10 and O101: H9-ST167 strains carrying fosA3 and bla CTX-M-14 among diarrheal calves in a Chinese farm, with Australian Chroicocephalus as the possible origin of E. coli O101: H9-ST10.

During a 2018 antimicrobial resistance surveillance of Escherichia coli isolates from diarrheal calves in Xinjiang Province, China, an unexpectedly high prevalence (48.5%) of fosfomycin resistance was observed. This study aimed to reveal the determinants of fosfomycin resistance and the underlying transmission mechanism. Polymerase chain reaction (PCR) screening showed that all fosfomycin-resistant E. coli carried the fosA3 gene. Pulsed-field gel electrophoresis (PFGE) and southern blot hybridization revealed that the 16 fosA3-positive isolates belonged to four different PFGE patterns (i.e., A, B, C, D). The fosA3 genes of 11 clonally related strains (pattern D) were located on the chromosome, while others were carried by plasmids. Whole-genome and long-read sequencing indicated that the pattern D strains were E. coli O101: H9-ST10, and the pattern C, B, and A strains were O101: H9-ST167, O8: H30-ST1431, and O101: H9 with unknown ST, respectively. Among the pattern C strains, the bla CTX-M-14 gene was co-localized with the fosA3 gene on the F18: A-: B1 plasmids. Interestingly, phylogenetic analysis based on core genome single nucleotide polymorphisms (cgSNPs) showed that the O101: H9-ST10 strains were closely related to a Australian-isolated Chroicocephalus-origin E. coli O101: H9-ST10 strain producing CTX-M-14 and FosA3, with a difference of only 11 SNPs. These results indicate possible international dissemination of the high-risk E. coli clone O101: H9-ST10 by migratory birds.

[Retrieval of leaf net photosynthetic rate of moso bamboo forests using hyperspectral remote sen-sing based on wavelet transform].

This study focused on retrieval of net photosynthetic rate (Pn) of moso bamboo forest based on analysis of wavelet transform on hyperspectral reflectance data of moso bamboo forest leaf. The result showed that the accuracy of Pn retrieved by the ideal high frequency wavelet vegetation index ( VI) was higher than that retrieved by low frequency wavelet VI and spectral VI. Normalized difference vegetation index of wavelet (NDVIw), simple ratio vegetation index of wavelet (SRw) and difference vegetation index of wavelet (Dw) constructed by the first layer of high frequency coefficient through wavelet decomposition had the highest relationship with Pn, with the R² of 0.7 and RMSE of 0.33; low frequency wavelet VI had no advantage compared with spectral VI. Significant correlation existed between Pn estimated by multivariate linear model constructed by the ideal wavelet VI and the measured Pn, with the R² of 0.77 and RMSE of 0.29, and the accuracy was significantly higher than that of using the spectral VI. Compared with the fact that sensitive spectral bands of the retrieval through spectral VI were limited in the range of visible light, the wavelength of sensitive bands of wavelet VI ranged more widely from visible to infrared bands. The results illustrated that spectrum of wavelet transform could reflect the Pn of moso bamboo more in detail, and the overall accuracy was significantly improved than that using the original spectral data, which provided a new alternative method for retrieval of Pn of moso bamboo forest using hyper spectral remotely sensed data.

[Retrieval of crown closure of moso bamboo forest using unmanned aerial vehicle (UAV) remotely sensed imagery based on geometric-optical model].

This research focused on the application of remotely sensed imagery from unmanned aerial vehicle (UAV) with high spatial resolution for the estimation of crown closure of moso bamboo forest based on the geometric-optical model, and analyzed the influence of unconstrained and fully constrained linear spectral mixture analysis (SMA) on the accuracy of the estimated results. The results demonstrated that the combination of UAV remotely sensed imagery and geometric-optical model could, to some degrees, achieve the estimation of crown closure. However, the different SMA methods led to significant differentiation in the estimation accuracy. Compared with unconstrained SMA, the fully constrained linear SMA method resulted in higher accuracy of the estimated values, with the coefficient of determination (R2) of 0.63 at 0.01 level, against the measured values acquired during the field survey. Root mean square error (RMSE) of approximate 0.04 was low, indicating that the usage of fully constrained linear SMA could bring about better results in crown closure estimation, which was closer to the actual condition in moso bamboo forest.

In silico identification of novel kinase inhibitors by targeting B-Raf(v660e) from natural products database.

The Ras/Raf/MEK/ERK (MAPK) signaling pathway has gained much attention from scientific community for therapeutic intervention in the past decades, specifically in oncology. Notably, a most prevalent B-Raf(v600e) mutant in Raf kinase family exhibits elevated kinase activity and results in constitutive activation of the MAPK pathway, thus making it a promising drug target for cancer therapy. Herein, virtual screening is applied to identify its potential inhibitors. Following the 25 ns molecular dynamic (MD) simulations, ZINC38541768, ZINC38541767, and ZINC12496469 are identified as B-Raf(v600e) potential inhibitors in a DFG-in conformation. Furthermore, according to the molecular mechanics/generalized born surface area (MM/GBSA) method, these three small molecules exhibit similar and good binding affinity toward B-Raf(v600e) (-38.76 kcal mol(-1), -42.60 kcal mol(-1), and -39.04 kcal mol(-1)). At the same time, several critical residues, such as I463, V471 in the P-loop, and DFG motif residue D594 within the A-loop, are also well clarified. All these results may not only indicate some future applications of inhibitors targeting B-Raf(v600e), but also benefit B-Raf(v600e) harboring cancer patients.