Water-soluble organic matter with various polarities in PM_(2.5) over Xi'an,China:Abundance,functional groups,and light absorption

Humic-like substances(HULIS)are a major component of brown carbon and consequently play a major role in climate change.In this study,70 PM_(2.5) samples were collected from Xi'an in winter 2019 and summer 2020.Neutral HULIS(HULIS-n),acidic HULIS(HULIS-a),and high-polarity water-soluble organic compounds(HP-WSOC)were analyzed to determine their carbon concentrations and measure their ultraviolet-visible absorption and infrared spectra.Of the three components,HULIS-n had the highest carbon content in both winter(3.29±1.45μg m^(-3))and in summer(1.38±1.10μg m^(-3)).The semi-quantitative results for the functional groups revealed that HP-WSOC was rich in carboxylic acids and had high aromaticity in winter,whereas HULIS-n was rich in carboxylic acids in summer.Moreover,HULJS-a was richer in nitrate esters and saturated aliphatic hydrocarbons in summer than in winter.The results for specific ultraviolet absorbance(SUVA)and E_(250)/E_(365) revealed that HULIS had higher molecular weight and aromaticity in winter than in summer.HULIS-n dominated in the total light absorption of HULIS+HP-WSOC in both winter(73.08%)and summer(48.57%).Overall,the results on the carbon content,optical properties,and functional groups of WSOCs with differing polarity can improve un-derstanding of environmental and climatic effects.

Development and performance evaluation of a culture-independent nanopore amplicon-based sequencing method for accurate typing and antimicrobial resistance profiling in Neisseria gonorrhoeae

Dear Editor,Bacterial antimicrobial resistance(AMR)poses a serious threat to global human health(Antimicrobial Resistance Collaborators,2022).Comprehensive profiling of AMR and accurate molecular typing are important for tracking and controlling the emergence and dissemination of antibiotic-resistant bacteria(Yahara et al.,2021).We previously developed a multiplex amplicon sequencing-based method for directly sequencing AMR-related loci in N.gonorrhoeae from clinical samples(Zhang et al.,2021).

The potential development of drug resistance in rheumatoid arthritis patients identified with p53 mutations

Rheumatoid arthritis(RA)is a chronic inflammatory disease characterized by cartilage and bone damage with the presence of pannus formation which causes uncontrollable proliferation and invasion of fibroblast-like synoviocytes(FLS).Since rheumatoid arthritis is a chronic disorder,the patients normally need to undergo prolonged antirheumatic treatment with the use of disease-modifying antirheumatic drugs(DMARDs),steroids,and nonsteroidal anti-inflammatory drugs(NSAIDs).The efficacy of such long-term pharmaceutical intervention can be significantly affected by the development of drug resistance.The pathological relationship between rheumatoid arthritis and cancer hinted that some chemotherapeutic drugs,such as methotrexate(MTX),could be used for RA treatment.This idea was reinforced by the analysis of mutations in p53 tumor suppressor gene.Around 50%of p53 somatic mutations observed from various cancers are also identified in the synovium of RA patients1(Fig.1A).Of note,the hyperplastic synovium in RA with overexpressed p53 mutants contributed to the destruction of joints in patients with erosive RA.

Determining antimicrobial resistance profiles and identifying novel mutations of Neisseria gonorrhoeae genomes obtained by multiplexed MinION sequencing

Gonorrhea is one of the most common sexually transmitted diseases worldwide. To cure infection and prevent transmission,timely and appropriate antimicrobial therapy is necessary. Unfortunately, Neisseria gonorrhoeae, the etiological agent of gonorrhea, has acquired nearly all known mechanisms of antimicrobial resistance(AMR), thereby compromising the efficacy of antimicrobial therapy. Treatment failure resulting from AMR has become a global public health concern. Whole-genome sequencing is an effective method to determine the AMR characteristics of N. gonorrhoeae. Compared with next-generation sequencing, the MinION sequencer(Oxford Nanopore Technologies(ONT)) has the advantages of long read length and portability. Based on a pilot study using MinION to sequence the genome of N. gonorrhoeae, we optimized the workflow of sequencing and data analysis in the current study. Here we sequenced nine isolates within one flow cell using a multiplexed sequencing strategy. After hybrid assembly with Illumina reads, nine integral circular chromosomes were obtained. By using the online tool Pathogenwatch and a BLAST-based workflow, we acquired complete AMR profiles related to seven classes of antibiotics. We also evaluated the performance of ONT-only assemblies. Most AMR determinants identified by ONT-only assemblies were the same as those identified by hybrid assemblies. Moreover, one of the nine assemblies indicated a potentially novel antimicrobial-related mutation located in mtrR which results in a frame-shift, premature stop codon, and truncated peptide.In addition, this is the first study using the MinION sequencer to obtain complete genome sequences of N. gonorrhoeae strains which are epidemic in China. This study shows that complete genome sequences and antimicrobial characteristics of N.gonorrhoeae can be obtained using the MinION sequencer in a simple and cost-effective manner, with hardly any knowledge of bioinformatics required. More importantly, this strategy provides us with a potential approach to discover new AMR determinants.