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Because anthropogenic nitroaromatic compounds have entered the biosphere relatively recently, exploration of the recently evolved catabolic pathways can provide clues for adaptive evolutionary mechanisms in bacteria. The concept that nitroarene dioxygenases shared a common ancestor with naphthalene dioxygenase is well established. Diaphorobacter sp. strain JS3051 utilizes 2,3-dichloronitrobenzene (23DCNB), a toxic anthropogenic compound, as the sole carbon, nitrogen, and energy source for growth, but the metabolic pathway and its origins are unknown. Here, we establish that a gene cluster ( dcb ), encoding a Nag-like dioxygenase, is responsible for the initial oxidation of the 23DCNB molecule. The 2,3-dichloronitrobenzene dioxygenase system (DcbAaAbAcAd) catalyzes conversion of 23DCNB to 3,4-dichlorocatechol (34DCC). Site-directed mutagenesis studies indicated that residue 204 of DcbAc is crucial for the substrate specificity of 23DCNB dioxygenase. The presence of glutamic acid at position 204 of 23DCNB dioxygenase is unique among Nag-like dioxygenases. Genetic, biochemical, and structural evidence indicate that the 23DCNB dioxygenase is more closely related to 2-nitrotoluene dioxygenase from Acidovorax sp. strain JS42 than to the 34DCNB dioxygenase from Diaphorobacter sp. strain JS3050, which was isolated from the same site as strain JS3051. A gene cluster ( dcc ) encoding the enzymes for 34DCC catabolism, homologous to a clc operon in Pseudomonas knackmussii strain B13, is also on the chromosome at a distance of 2.5 Mb from the dcb genes. Heterologously expressed DccA catalyzed ring cleavage of 34DCC with high affinity and catalytic efficiency. This work not only establishes the molecular mechanism for 23DCNB mineralization, but also enhances the understanding of the recent evolution of the catabolic pathways for nitroarenes. IMPORTANCE Because anthropogenic nitroaromatic compounds have entered the biosphere relatively recently, exploration of the recently evolved catabolic pathways can provide clues for adaptive evolutionary mechanisms in bacteria. The concept that nitroarene dioxygenases shared a common ancestor with naphthalene dioxygenase is well established. But their phylogeny and how they evolved in response to novel nitroaromatic compounds are largely unknown. Elucidation of the molecular basis for 23DCNB degradation revealed that the catabolic pathways of two DCNB isomers in different isolates from the same site were derived from different recent origins. Integrating structural models of catalytic subunits and enzymatic activities data provided new insight about how recently modified enzymes were selected depending on the structure of new substrates. This study enhances understanding and prediction of adaptive evolution of catabolic pathways in bacteria in response to new chemicals.

Metabolism and gut microbiota are essential for newborn health, influencing immune function, energy balance, and growth. Breast milk provides IgA, crucial for shaping gut microbiota in infants. In non-breastfed newborns, we observe the presence of IgM antibodies that can recognize various bacteria, influence bacterial clustering, and alter bacterial metabolism, such as carbon source utilization in vitro within small bacterial communities. Based on these findings, we developed a monoclonal IgM, M291, derived from a newborn-B cell, which mimics naturally occurring antibodies and could serve as a surrogate tool to modulate intestinal bacterial functions and metabolism. Oral administration of M291 alters the metabolome of germ-free mice colonized with a defined bacterial consortium or an infant gut microbiota, by modulating the bacterial transcriptome, while maintaining microbial abundance and diversity. This study establishes proof of concept for the design and application of newborn-derived antibodies to modulate microbial and host metabolism, including lipid metabolism and bile acid secretion, without significantly altering microbiota composition. Here, the authors characterize a newborn-derived monoclonal IgM, showing it influences bacterial clustering, gene expression, and metabolic activity, thereby modulating gut bacterial functions and host metabolism without altering microbiota composition.

The spike‐in plasmid method was utilized to perform an analysis on meconium and second‐pass feces, yielding both relative and absolute quantitative results. With the absolute quantitative data, the abundance of bacteria in 17 meconium samples and 17 second‐pass fecal samples were found to be 1.14 × 107 and 1.59 × 109 copies/g, respectively. The mode of delivery can significantly influence the alterations and compositions of gut bacteria in a newborn within 72 h.

Articular cartilage and cartilage matrix degradation are key pathological changes occurring in the early stage of knee osteoarthritis (KOA). However, currently, there are limited strategies for early prevention and treatment of KOA. Duhuo Jisheng Decoction (DHJSD) is a formula quoted in Bei Ji Qian jin Yao Fang, which was compiled by Sun Simiao in the Tang Dynasty of China. As a complementary therapy, it is widely used to treat early-stage KOA in China; however, its mechanism has not been completely elucidated. This study investigated the potential role of DHJSD in preventing cartilage degradation and the underlying mechanism. A rat model of KOA model was established via the Hulth method. Subsequently, 25 rats were randomized into sham (saline), model control (saline), high-DHJSD (1.9g/mL of DHJSD), medium-DHJSD (1.2g/mL of DHJSD), and low-DHJSD groups (0.6g/mL of DHJSD). After 4 weeks of treatment, all rats were sacrificed and the severity of the cartilage degeneration was evaluated by a series of histological methods. The autophagosome was observed using transmission electron microscopy, and the related functional proteins were detected by the western blotting and real-time polymerase chain reaction. Next, the mechanism by which DHJSD improves knee cartilage degeneration was further clarified the in vitro by gene silencing technology combined with a series of functional experiments. The proteins levels of PTEN, Akt, p-Akt, mTOR, and p-mTOR, as well as the marker proteins of autophagy and apoptosis were determined. Zinc levels in chondrocytes were determined using inductively coupled plasma mass spectrometry. Histopathological staining revealed that DHJSD had a protective effect on the cartilage. DHJSD increased autophagosome synthesis and the expression of autophagy proteins LC3 and Beclin-1 in chondrocytes. Moreover, it reduced the phosphorylation levels of Akt and mTOR and the levels of zinc, MMP-13, Bax, and Bcl-2. Following PTEN silencing, this DHJSD-mediated reduction in Akt and mTOR phosphorylation and Bax, Bcl-2, and zinc levels were further decreased; in addition, DHJSD-mediated increase in LC3 and Beclin-1 levels was decreased. DHJSD inhibits the Akt/mTOR signaling pathway by targeting PTEN to promote autophagy in chondrocytes, which may help reduce MMP-13 production by regulating zinc levels in chondrocytes.

CRISPR-Cas systems are prevalent in bacterial and archaeal genomes, and these systems provide a powerful adaptive immune system against predation by phages and other mobile genetic elements (MGEs). They also contribute to other functions, such as gene regulation in prokaryotic organisms. Determining Cas proteins and Cas loci can help mine Cas proteins and facilitate the identification of Cas-associated accessory proteins. Therefore, the purpose of this work is to develop a web-based server, CasLocusAnno, to annotate Cas proteins and Cas loci and to classify them according to (sub)type based on a previous study. CasLocusAnno can annotate Cas proteins and Cas loci and assign their (sub)types within ~28 seconds for whole protein sequence submissions, with protein sequence numbers ranging from ~30 to ~10500. Comparison with Makarova et al's benchmark data demonstrates that CasLocusAnno can accurately identify Cas loci and (sub)types. In addition, CasLocusAnno can identify Cas proteins with higher accuracy and a lower additional prediction rate (APR) than two excellent software programs, CRISPRCasFinder and MacSyFinder. The domain alignment of a Cas protein can be easily browsed in the annotation results. Our server can be freely accessed at http://cefg.uestc.edu.cn/CasLocusAnno/.

Background：The conventional venous access for cardiovascular implantable electronic device （CIED） is the subclavian vein,which is often accompanied by high complication rate.The aim of this study was to assess the efficacy and safety of optimized axillary vein technique.Methods：A total of 247 patients undergoing CIED implantation were included and assigned to the axillary vein group or the subclavian vein group randomly.Success rate of puncture and complications in the perioperative period and follow-ups were recorded.Results：The overall success rate （95.7% vs.96.0%） and one-time success rate （68.4% vs.66.1%） of punctures were similar between the two groups.In the subclavian vein group,pneumothorax occurred in three patients.The subclavian gaps of three patients were too tight to allow operation of the electrode lead.In contrast,there were no puncture-associated complications in the axillary vein group.In the patient follow-ups,two patients in the subclavian vein group had subclavian crush syndrome and both of them received lead replacement.The incidence of complications during the perioperative period and follow-ups of the axillary vein group and the subclavian vein group was 1.6% （2/125） and 8.2% （10/122）,respectively （χ^2=5.813,P =0.016）.Conclusion：Optimized axillary vein technique may be superior to the conventional subclavian vein technique for CIED lead placement.

To the Editor： Chest abdominal wall defects are usually the result of tumor resection, infection, radiation, or trauma. Chest abdominal wall neoplasms are classified as primary, locally invading, or metastatic. The most common primary malignancies in the chest wall are the soft tissue and bone sarcomas.In most patients, the operations of the following defect locations are at the risk of herniation or paradoxical breathing postsurgery： total or subtotal sternal resection including several ribs bilaterally or high lateral resection （more than 3-4 ribs）. In these cases, patients are prone to develop respiratory problems, if the stability is not adequate as early＇ as during the immediate postoperative period .

Background： Previously, we reported that dual-specificity adenocarcinoma （EEA）. However, the role of DUSP1 medroxyprogesterone （MPA） are still unclear. phosphatase I （DUSPI） was differentially expressed in endometrioid in EEA progression and the relationship between DUSPI and Methods： The expression of DUSPI in EEA specimens was detected by immunohistochemical analysis. The effect of DUSPI on cell proliferation was analyzed by Cell Counting Kit 8 and colony formation assay, and cell migration was analyzed by transwell assay. MPA-induced DUSPI expression in EEA cells was measured by Western blot. Results： DUSPI expression was deficient in advanced International Federation of Gynecology and Obstetrics stage, high-grade and myometrial invasive EEA. In EEA cell lines （HeclA, Hecl B, RL952, and Ishikawa）, the DUSP1 expression was substantially higher in lshikawa cells than in other cell lines （P 〈 0.05）. Knockdown ofDUSP I promoted lshikawa cells proliferation, migration, and activation of mitogen-activated protein kinases/extracellular signal-regulated kinase （MAPK/Erk） pathway. MPA-induced DUSP1 expression and inhibited MAPK/Erk pathway in Ishikawa cells. Conclusions： Our data suggest that DUSP1 deficiency promotes EEA progression via MAPK/Erk pathway, which may be reversed by MPA, suggesting that DUSP I may serve as a potential therapeutic target for the treatment of EEA.

Flexible electrochemical capacitors (ECs) are vitally important as the emerging flexible electronics. We have prepared polypyrrole doped with counter ion of Cl− on carbon fibers (PPy-Cl/CFs) via the simple electrochemical deposition method. The flexible ECs based on PPy-Cl/CFs electrodes have been assembled by using H3PO4/poly(vinyl alcohol) (PVA), H2SO4/PVA, LiClO4/PVA, KCl/PVA and LiCl/PVA as gel electrolytes. The capacitive properties of ECs have been systematically evaluated with electrochemical methods. The results show that the cells with H3PO4/PVA electrolyte exhibit good cyclic stability (91.5% retention after 15000 cycles) although PPy-Cl/CFs has moderate specific capacitance in H3PO4/PVA (41.6 mF·cm−1 or 52.0 F·cm−3). However, the ECs in other electrolytes have poor cyclic stability. Further electrochemical analysis reveals that the doping/dedoping processes of PPy-Cl/CFs are different in the five electrolytes, and X-ray photoelectron spectra demonstrate that the ratios of counter anions in PPy’s oxidized states to those in reduced states are obviously different when PPy-Cl/CFs are kept in reduced or oxidized states in the five electrolytes. The results also illustrate why the capacitors using H3PO4/PVA as electrolyte exhibit good cyclic stability. Furthermore, a light emitting diode (LED) with a threshold voltage of 2.5 V can be lighted by three ECs connected in series.