1.The Diversity of Filamentous Morphologies and Magnetic Sensitivity Modulated by Diverse MagR Expression in Bacteria
Ya-Fei CHANG ; Jing ZHANG ; Peng ZHANG ; Xiu-Juan ZHOU ; Meng-Ke WEI ; Tian-Tian CAI ; Pei-Qi HE ; Jun-Feng WANG ; Can XIE
Progress in Biochemistry and Biophysics 2026;53(5):1439-1456
Objective Magnetoreception, the remarkable ability of diverse animals to sense and utilize the geomagnetic field for orientation and navigation, remains a molecularly unresolved mystery in sensory biology. The putative magnetoreceptor (MagR, previously known as IscA1) is a highly conserved iron-sulfur protein implicated in both magnetoreception and iron metabolism; however, the functional diversity among its cross-species homologs remains poorly understood. Cellular morphology is a key genetically determined trait that can be altered through genetic or environmental modifications—a process known as cell morphology engineering. Constructing engineered cells with specific morphological features and magnetic sensitivity to achieve remote, non-invasive magnetic modulation represents a crucial goal in this field with significant application potential. Therefore, this study aims to systematically investigate the effects of MagR heterologous expression on bacterial morphology and magnetic sensing capabilities, screen for MagR-based magnetically sensitive morphology engineering pathways, and reveal the underlying molecular mechanisms. Methods We systematically screened 28 MagR homologous genes from diverse prokaryotic and animal taxa to evaluate their expression and corresponding phenotypic effects in Escherichia coli (E. coli). To compare the differential magnetic responses among bacteria expressing various recombinant MagR proteins, we utilized high-throughput automated bright-field microscopic imaging and scanning electron microscopy (SEM). Furthermore, comprehensive biochemical and biophysical characterizations of iron and iron-sulfur cluster binding were performed using Ferrozine colorimetric assays, electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopy. Additionally, 100 mT static magnetic field (SMF) exposure experiments were conducted to assess magnetically tunable phenotypes, while the intrinsic magnetic properties of purified MagR proteins were directly measured using a superconducting quantum interference device (SQUID) magnetometer. Results Our results demonstrated that the heterologous expression of MagR homologs induced varying degrees of bacterial filamentation. From this comprehensive screen, two distinct morphological patterns were identified: hydra (Hydra vulgaris) MagR (hyMagR) promoted uniform cell elongation and filamentation, exhibiting robust magnetic sensitivity manifested as significantly enhanced filamentation under the 100 mT SMF. In contrast, pigeon (Columba livia) MagR (clMagR) induced only low-frequency, extreme filamentation (sporadically exceeding 80 μm) with a relatively weaker magnetic morphological response. Mechanistically, our data unambiguously proved that these phenotypic differences are primarily driven by distinct iron redox preferences rather than total cellular iron accumulation. Specifically, hyMagR preferentially binds ferrous iron (Fe2+), whereas clMagR favors ferric iron (Fe3+) and forms more stable iron-sulfur clusters. Intriguingly, although SQUID magnetometry showed that purified clMagR exhibited approximately five-fold higher mass magnetic susceptibility than hyMagR, its cellular magnetic response was weaker. We hypothesize that the Fe2+-preferred intracellular environment associated with hyMagR overexpression primes the cell for enhanced generation of reactive oxygen species (ROS) via the Fenton reaction. Exposure to an SMF synergizes with this primed redox state, triggering the bacterial SOS response and upregulating cell division inhibitors to efficiently induce uniform filamentation. Conclusion Our findings identify the Fe2+/Fe3+ redox state as a critical determinant of MagR-mediated morphological remodeling and magnetic responsiveness. This discovery suggests a potential strategy for engineering magnetically responsive cellular systems for synthetic biology applications, and provides a plausible framework, which potentially combines intrinsic protein magnetism with redox-state modulation, for further investigating the evolutionary mechanisms of MagR-mediated magnetoreception.
2.The Diversity of Filamentous Morphologies and Magnetic Sensitivity Modulated by Diverse MagR Expression in Bacteria
Ya-Fei CHANG ; Jing ZHANG ; Peng ZHANG ; Xiu-Juan ZHOU ; Meng-Ke WEI ; Tian-Tian CAI ; Pei-Qi HE ; Jun-Feng WANG ; Can XIE
Progress in Biochemistry and Biophysics 2026;53(5):1439-1456
Objective Magnetoreception, the remarkable ability of diverse animals to sense and utilize the geomagnetic field for orientation and navigation, remains a molecularly unresolved mystery in sensory biology. The putative magnetoreceptor (MagR, previously known as IscA1) is a highly conserved iron-sulfur protein implicated in both magnetoreception and iron metabolism; however, the functional diversity among its cross-species homologs remains poorly understood. Cellular morphology is a key genetically determined trait that can be altered through genetic or environmental modifications—a process known as cell morphology engineering. Constructing engineered cells with specific morphological features and magnetic sensitivity to achieve remote, non-invasive magnetic modulation represents a crucial goal in this field with significant application potential. Therefore, this study aims to systematically investigate the effects of MagR heterologous expression on bacterial morphology and magnetic sensing capabilities, screen for MagR-based magnetically sensitive morphology engineering pathways, and reveal the underlying molecular mechanisms. Methods We systematically screened 28 MagR homologous genes from diverse prokaryotic and animal taxa to evaluate their expression and corresponding phenotypic effects in Escherichia coli (E. coli). To compare the differential magnetic responses among bacteria expressing various recombinant MagR proteins, we utilized high-throughput automated bright-field microscopic imaging and scanning electron microscopy (SEM). Furthermore, comprehensive biochemical and biophysical characterizations of iron and iron-sulfur cluster binding were performed using Ferrozine colorimetric assays, electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopy. Additionally, 100 mT static magnetic field (SMF) exposure experiments were conducted to assess magnetically tunable phenotypes, while the intrinsic magnetic properties of purified MagR proteins were directly measured using a superconducting quantum interference device (SQUID) magnetometer. Results Our results demonstrated that the heterologous expression of MagR homologs induced varying degrees of bacterial filamentation. From this comprehensive screen, two distinct morphological patterns were identified: hydra (Hydra vulgaris) MagR (hyMagR) promoted uniform cell elongation and filamentation, exhibiting robust magnetic sensitivity manifested as significantly enhanced filamentation under the 100 mT SMF. In contrast, pigeon (Columba livia) MagR (clMagR) induced only low-frequency, extreme filamentation (sporadically exceeding 80 μm) with a relatively weaker magnetic morphological response. Mechanistically, our data unambiguously proved that these phenotypic differences are primarily driven by distinct iron redox preferences rather than total cellular iron accumulation. Specifically, hyMagR preferentially binds ferrous iron (Fe2+), whereas clMagR favors ferric iron (Fe3+) and forms more stable iron-sulfur clusters. Intriguingly, although SQUID magnetometry showed that purified clMagR exhibited approximately five-fold higher mass magnetic susceptibility than hyMagR, its cellular magnetic response was weaker. We hypothesize that the Fe2+-preferred intracellular environment associated with hyMagR overexpression primes the cell for enhanced generation of reactive oxygen species (ROS) via the Fenton reaction. Exposure to an SMF synergizes with this primed redox state, triggering the bacterial SOS response and upregulating cell division inhibitors to efficiently induce uniform filamentation. Conclusion Our findings identify the Fe2+/Fe3+ redox state as a critical determinant of MagR-mediated morphological remodeling and magnetic responsiveness. This discovery suggests a potential strategy for engineering magnetically responsive cellular systems for synthetic biology applications, and provides a plausible framework, which potentially combines intrinsic protein magnetism with redox-state modulation, for further investigating the evolutionary mechanisms of MagR-mediated magnetoreception.
3.Traditional Chinese Medicine Alleviates Dry Eye Disease by Regulating Tear Film Homeostasis: A Review
Sainan TIAN ; Bin'an WANG ; Yao CHEN ; Guicheng LIU ; Li TANG ; Pei LIU ; Genyan QIN ; Jun PENG ; Qinghua PENG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(7):172-181
Dry eye (DE) is a prevalent multifactorial disease of the ocular surface, clinically characterized by tear film homeostasis imbalance accompanied by related ocular surface symptoms. Specifically, the tear film is a thin liquid layer of tears covering the cornea and conjunctiva through blinking, while tear film homeostasis serves as the foundation for maintaining normal ocular surface structure and function. Insufficient tear secretion and excessive tear film evaporation lead to tear hyperosmolarity and the production of inflammatory mediators, disrupting tear film homeostasis and subsequently forming DE. Additionally, cascade reactions are triggered, resulting in a "vicious cycle of DE" that exacerbates the disease severity and prolongs its duration. Therefore, for DE treatment, it is crucial to restore tear film homeostasis and terminate this vicious cycle. Traditional Chinese medicine (TCM), which differentiates and treats DE based on systemic conditions, often achieves favorable therapeutic outcomes, offering additional treatment options for DE. Studies have demonstrated that TCM can alleviate DE by regulating tear film homeostasis and terminating the vicious cycle. This review systematically summarizes recent basic experimental research in China and abroad on TCM in alleviating DE by regulating tear film homeostasis, aiming to provide a theoretical basis for clinical treatment and an insight for research design.
4.Effect of Runmu Dihuang Decoction on Perimenopausal Dry Eye in Rats with Liver-kidney Yin Deficiency Syndrome Based on SIRT3/HIF-1α/NF-κB Signaling Pathway
Sainan TIAN ; Wei MA ; Yao CHEN ; Yu CAO ; Guicheng LIU ; Pei LIU ; Junxian LEI ; Qinghua PENG ; Jun PENG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(7):201-210
ObjectiveTo investigate the mechanisms of Runmu Dihuang decoction (RMDHD) in treating perimenopausal dry eye with liver-kidney Yin deficiency syndrome based on the silent information regulator 3 (SIRT3)/hypoxia-inducible factor-1α (HIF-1α)/nuclear factor-κB (NF-κB) signaling pathway. MethodsSixty female Sprague-Dawley rats were randomly divided into six groups (n=10 per group): Sham operation group, model group, sodium hyaluronate eye drop group, and low-, medium-, and high-dose RMDHD groups (5.625, 11.25, 22.50 g·kg-1). Except for the sham operation group, all rats underwent bilateral ovariectomy and were administered 0.1% benzalkonium chloride eye drops combined with long-term chronic irritation to establish a perimenopausal dry eye model with liver-kidney Yin deficiency syndrome. Drug administration began in the 11th week after modeling and continued for 21 days. General conditions, screen-grip test scores, tear secretion volume, tear film breakup time (TFBUT), and corneal fluorescein staining were recorded. Serum levels of reactive oxygen species (ROS), follicle-stimulating hormone (FSH), estradiol (E2), and progesterone (PROG) were measured by enzyme-linked immunosorbent assay (ELISA). Pathological changes in the lacrimal glands, corneas, and uteri were observed using hematoxylin-eosin (HE) staining. Protein expression levels of SIRT3, HIF-1α, phosphorylated NF-κB p65 (p-NF-κB p65), and total NF-κB p65 in the lacrimal glands were detected by Western blot. The expression of inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the lacrimal glands was assessed by immunohistochemistry (IHC). ResultsAfter model establishment, no significant differences were observed among the groups except the sham operation group. Compared with the sham operation group, the other groups exhibited slowed movement, dull responses, increased irritability, reduced body weight, elevated rectal temperature, decreased screen-grip test scores, reduced tear secretion, and significantly shortened TFBUT (P<0.05). After treatment, compared with the model group, the sodium hyaluronate eye drop group and all RMDHD groups showed improved general conditions, significantly increased tear secretion (P<0.05), prolonged TFBUT (P<0.05), and elevated screen-grip test scores (P<0.05). Serum ROS and FSH levels were significantly decreased, while E2 and PROG levels were significantly increased (P<0.05). Pathological damage to the cornea, lacrimal glands, and uterus was ameliorated. In addition, protein expression levels of SIRT3 and HIF-1α in the lacrimal glands were significantly upregulated (P<0.05), whereas the expression of p-NF-κB p65, IL-1β, and TNF-α was significantly downregulated (P<0.05). ConclusionRMDHD increases tear secretion and TFBUT, improves lacrimal gland and corneal injury, and alleviates dry eye symptoms in a perimenopausal dry eye rat model with liver-kidney Yin deficiency syndrome. The underlying mechanism may be related to regulation of the SIRT3/HIF-1α/NF-κB signaling pathway, inhibition of oxidative stress and inflammatory responses, and reduction of ocular surface tissue damage.
5.Mechanism of MEK/Ras/Raf/ERK Signaling Pathway Modulated by Mimenghua Prescription on Inflammatory Response in Dry Eye Animal Model
Shi TAN ; Pei LIU ; Yuan ZHONG ; Sainan TIAN ; Pengfei JIANG ; Genyan QIN ; Qinghua PENG ; Jun PENG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(7):211-221
ObjectiveThis paper aims to investigate the effects and mechanism of Mimenghua prescription in modulating the mitogen-activated protein kinase kinase (MEK)/rat sarcoma viral oncogene homolog (Ras)/rapidly accelerated fibrosarcoma kinase (Raf)/extracellular signal-regulated kinase (ERK) signaling pathway to inhibit inflammatory responses in a dry eye animal model. MethodsA total of 60 C57BL/6J mice (eight weeks old, half male and half female) were used in the experiment. Ten mice were randomly selected as the blank control group, while the remaining 50 were exposed to a controlled dry system and received instillation of 0.2% benzalkonium chloride (BAC) into the eyes for four weeks to establish a dry eye mouse model. After successful modeling, the mice were randomly divided into five groups: Model group, sodium hyaluronate group, and Mimenghua prescription groups with low dose (4.83 g·kg-1), medium dose (9.67 g·kg-1), and high dose (19.34 g·kg-1). The mice in the model group received an equal volume of normal saline via gavage for four weeks. The mice in the sodium hyaluronate group received instillation of sodium hyaluronate eye drops twice daily for 14 consecutive days. The tear secretion volume, tear film break-up time (TBUT), and corneal fluorescein staining were evaluated once every two weeks. After four weeks of administration, mice were euthanized, and their lacrimal gland tissues and corneas were harvested. Hematoxylin-eosin (HE) staining was used to assess histopathological morphology. Western blot was performed to detect the protein expression levels of MEK, Ras, Raf, and ERK. Enzyme-linked immunosorbent assay (ELISA) was used to measure the contents and expressions of MEK, Ras, Raf, ERK, and interleukin (IL)-1β in lacrimal gland and corneal tissues of the mice in each group. Quantitative real-time polymerase chain reaction (Real-time PCR) was employed to determine mRNA expression levels of MEK, Ras, Raf, and ERK. ResultsThe Mimenghua prescription groups and the sodium hyaluronate group exhibited significantly increased tear secretion volume (P<0.05) and prolonged TBUT (P<0.05) after treatment. Ocular surface damage of mice was visibly recovered. Western blot results indicated that protein expression levels of MEK, Ras, Raf, and ERK in the lacrimal gland and corneal tissues were significantly downregulated in the sodium hyaluronate group and Mimenghua prescription group with high dose (P<0.05). ELISA results showed that IL-1β levels were highest in the model group but significantly reduced in the sodium hyaluronate group and Mimenghua prescription groups (P<0.05). Both ELISA and Real-time PCR results demonstrated that the expression levels of MEK, Ras, Raf, and ERK in the lacrimal glands and corneal tissues were significantly elevated in the model group (P<0.05), but markedly downregulated in the sodium hyaluronate group and Mimenghua prescription groups (P<0.05), suggesting that Mimenghua prescription can decrease the expressions of MEK, Ras, Raf, and ERK in the lacrimal glands and corneal tissues. ConclusionMimenghua prescription can reduce inflammatory responses, increase tear secretion, prolong TBUT, and promote corneal recovery by inhibiting the MEK, Ras, Raf, and ERK signaling pathways in lacrimal gland and corneal tissues.
6.GPX3 attenuates ischemia-reperfusion injury in kidney transplantation by inhibiting ROS-mediated NET formation
Jun PEI ; Hongyu TANG ; Moudong WU ; Jinpu PENG ; Nini AN ; Xingyu PAN
Organ Transplantation 2026;17(4):602-609
Objective To investigate the role and potential mechanism of glutathione peroxidase 3 (GPX3) in ischemia-reperfusion injury (IRI) during kidney transplantation. Methods C57BL/6 mice were divided into four groups according to different interventions: sham operation group (Sham group), kidney transplantation group (KT group), kidney transplantation + GPX3 overexpression group (KT+GPX3 group) and kidney transplantation + GPX3 overexpression + reactive oxygen species (ROS) agonist group (KT+GPX3+CADD522 group). Twenty-four hours after model establishment, inferior vena cava blood was collected to detect blood urea nitrogen (BUN) and serum creatinine (Scr). Left renal tissues were harvested for immunofluorescence staining to detect ROS and NADPH oxidase 2 (NOX2). Enzyme-linked immunosorbent assay (ELISA) was performed to measure neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), tumor necrosis factor (TNF) -α and interleukin (IL)-1β. Western blotting was used to detect myeloperoxidase (MPO) and citrullinated histone H3 (CitH3). Results Compared with the Sham group, the expression level of GPX3 was decreased in the KT group; compared with the KT group, GPX3 expression was increased in the KT+GPX3 group; compared with the KT+GPX3 group, GPX3 expression was reduced in the KT+GPX3+CADD522 group (all P<0.05). Compared with the Sham group, the levels of Scr, BUN, NGAL and KIM-1 were elevated in the KT group; compared with the KT group, the above indicators were decreased in the KT+GPX3 group; compared with the KT+GPX3 group, the levels of Scr, BUN, NGAL and KIM-1 were increased in the KT+GPX3+CADD522 group (all P<0.05). Compared with the Sham group, the expression levels of NOX2 and ROS were increased in the KT group; compared with the KT group, NOX2 and ROS levels were decreased in the KT+GPX3 group; compared with the KT+GPX3 group, NOX2 and ROS levels were upregulated in the KT+GPX3+CADD522 group (all P<0.05). Compared with the Sham group, the expression levels of MPO and CitH3 were increased in the KT group; compared with the KT group, MPO and CitH3 levels were decreased in the KT+GPX3 group; compared with the KT+GPX3 group, MPO and CitH3 levels were increased in the KT+GPX3+CADD522 group (all P<0.05). Compared with the Sham group, the expression levels of TNF-α and IL-1β were increased in the KT group; compared with the KT group, TNF-α and IL-1β levels were decreased in the KT+GPX3 group; compared with the KT+GPX3 group, TNF-α and IL-1β levels were increased in the KT+GPX3+CADD522 group (all P<0.05). Conclusions GPX3 may alleviate renal tissue inflammation by inhibiting ROS-mediated neutrophil extracellular trap (NET) formation, thereby attenuating IRI in renal transplantation.
7.Prevalence and molecular characterization of Shiga toxin-producing Esch-erichia coli in domestic goats in the Chengkou District of Chongqing
Jing-jing PENG ; Bin HU ; Xi YANG ; Yi LI ; Hai HUANG ; Wen-shuang LIU ; Yu MENG ; Li-jun WANG ; Yan-wen XIONG ; Yi YUAN ; Pei-bin HOU
Chinese Journal of Zoonoses 2025;41(5):529-536
This study investigated the infection status,drug resistance,and molecular characteristics of Shiga toxin-producing Escherichia coli(STEC)in domestic goats in Chengkou county,Chongqing.In August 2023,283 fecal samples were collected from households in Chengkou county.After enrichment with EC broth and inoculation onto selective media,samples that tested positive for stx1/stx2 were selected for further isolation.The positive strains were investigated with antimicrobial susceptibility testing and whole genome sequencing.According to the whole genomic sequences,the stx subtypes,serotypes,multi-locus sequence types,virulence genes,drug resistance genes,and phylogenetic relationships of the STEC strains were analyzed.Forty-six strains of STEC were isolated from 283 goat fecal samples,thus resulting in a detection rate of 16.25%.The 46 STEC strains were categorized into 12 O∶H serotypes,among which O76∶H19 and O8∶H7 predominated,each represented by 9 strains.Five STEC strains were identified as serotype O157∶H7.The 46 STEC strains were categorized into 11 sequence types(STs),among which ST675 and ST196 predominated,each represented by nine strains,accounting for a 19.57%proportion.The strains were categorized into 7 stx subtypes,among which stx1c(26/46,56.52%),followed by stx2k(9/46,19.57%)predominated.All nine Stx2k-STEC strains were identified as serotype O8∶H7 and sequence type ST196.In antimicrobial susceptibility testing,2 STEC strains were resistant to ampicillin,one strain was resistant to ampicillin/sulbactam,one strain was resistant to cefazolin,and one strain was resistant to cefoxitin.Nine Stx2k-STEC strains were found to carry the beta-lactam resistance gene blaEC-18.Antimicrobial sensitivity tests revealed that the nine Stx2k-STEC strains were sensitive to all 15 tested antibiotics.Moreover,phylogenetic analysis indicated that the 9 Stx2k-STEC strains were remarkably similar but showed high genetic diversity with respect to that of the Stx2k-STEC strains isolated from other regions in China.Goatsare an important animal reservoir for STEC in theChengkou district of Chongqing,and novel sequence type Stx2k-STEC strains distinct from those found in other regions of China were identified in this region.
8.circHERC4_041 Inhibits the Fibrotic Phenotype of Cardiac Fibroblasts by Encoding Protein
Yuan GAO ; Chuan-Meng ZHOU ; Hua-Yan WU ; Ya WANG ; Ru-Shi WU ; Pei-Ying GUAN ; Jun-Tao FANG ; Jin-Dong XU ; Yu-Peng LIU ; Zhi-Qin HU ; Zhi-Xin SHAN
Chinese Journal of Biochemistry and Molecular Biology 2025;41(3):393-403
A mounting body of research suggests that circRNAs significantly contribute to the develop-ment of myocardial fibrosis.The microarray results of human circular RNA expression profile indicated that circHERC4_041 expression increased in the myocardium of patients with heart failure,RT-qPCR a-nalysis confirmed that the myocardial expression level of circHERC4_041 in individuals with heart failure were considerably elevated compared to that in healthy organ donors.Fluorescence in situ hybridization(FISH)confirmed that circHERC4_041 was abundant in the cytoplasm of human cardiomyocyte AC16.Overexpression of circHERC4_041 in mouse myocardial fibroblasts(mCFs)mediated by adenovirus in-hibited the expression of fibrosis-related proteins in mCFs.Experiments involving cell proliferation,wound healing,and Transwell assays demonstrated that overexpression of circHERC4_041 suppressed the growth and mobility of mCFs(P<0.001).Sequence analysis results suggested that circHERC4_041 con-tains potential ribosome entry sequence(IRES)and open reading frame(ORF).Western blot confirmed that circHERC4_041 could translate the 516 amino acid HERC4-516aa protein,which was mainly located in the cytoplasm of the cell.Cell functional experiments confirmed that circHERC4_041 inhibited the fi-brotic phenotype of mCFs by specifically translating HERC4-516aa(P<0.05).The specific interaction between HERC4-516aa and transglutaminase 2(TGM2)was confirmed by IP-MS screening and Co-IP i-dentification.Further results found that the degradation of TGM2 was promoted through proteasome path-way.The overexpression of TGM2 in mCFs facilitated by adenoviral vectors could counteract the suppres-sive effects of HERC4-516aa on the fibrotic phenotype of mCFs.Therefore,this study confirmed that the HERC4-516aa protein translated by circHERC4_041 can specifically bind to TGM2 to inhibit the fibrotic phenotype of myocardial fibroblasts.
9.Prevalence and molecular characterization of Shiga toxin-producing Esch-erichia coli in domestic goats in the Chengkou District of Chongqing
Jing-jing PENG ; Bin HU ; Xi YANG ; Yi LI ; Hai HUANG ; Wen-shuang LIU ; Yu MENG ; Li-jun WANG ; Yan-wen XIONG ; Yi YUAN ; Pei-bin HOU
Chinese Journal of Zoonoses 2025;41(5):529-536
This study investigated the infection status,drug resistance,and molecular characteristics of Shiga toxin-producing Escherichia coli(STEC)in domestic goats in Chengkou county,Chongqing.In August 2023,283 fecal samples were collected from households in Chengkou county.After enrichment with EC broth and inoculation onto selective media,samples that tested positive for stx1/stx2 were selected for further isolation.The positive strains were investigated with antimicrobial susceptibility testing and whole genome sequencing.According to the whole genomic sequences,the stx subtypes,serotypes,multi-locus sequence types,virulence genes,drug resistance genes,and phylogenetic relationships of the STEC strains were analyzed.Forty-six strains of STEC were isolated from 283 goat fecal samples,thus resulting in a detection rate of 16.25%.The 46 STEC strains were categorized into 12 O∶H serotypes,among which O76∶H19 and O8∶H7 predominated,each represented by 9 strains.Five STEC strains were identified as serotype O157∶H7.The 46 STEC strains were categorized into 11 sequence types(STs),among which ST675 and ST196 predominated,each represented by nine strains,accounting for a 19.57%proportion.The strains were categorized into 7 stx subtypes,among which stx1c(26/46,56.52%),followed by stx2k(9/46,19.57%)predominated.All nine Stx2k-STEC strains were identified as serotype O8∶H7 and sequence type ST196.In antimicrobial susceptibility testing,2 STEC strains were resistant to ampicillin,one strain was resistant to ampicillin/sulbactam,one strain was resistant to cefazolin,and one strain was resistant to cefoxitin.Nine Stx2k-STEC strains were found to carry the beta-lactam resistance gene blaEC-18.Antimicrobial sensitivity tests revealed that the nine Stx2k-STEC strains were sensitive to all 15 tested antibiotics.Moreover,phylogenetic analysis indicated that the 9 Stx2k-STEC strains were remarkably similar but showed high genetic diversity with respect to that of the Stx2k-STEC strains isolated from other regions in China.Goatsare an important animal reservoir for STEC in theChengkou district of Chongqing,and novel sequence type Stx2k-STEC strains distinct from those found in other regions of China were identified in this region.
10.Investigation of the Mechanism of Cold Hyperalgesia in KOA Mice Relieved by Shangke Lengtongtie Based on HMGB1/CX-CL12/CXCR4 Signaling Axis
Yibao WEI ; Li ZHANG ; Taiyang LIAO ; Lishi JIE ; Zhenyuan MA ; Peng WU ; Zhengquan HUANG ; Li ZHANG ; Liang DING ; Wei MEI ; Runlin XING ; Songjiang YIN ; Xiaochen LI ; Nongshan ZHANG ; Jun MAO ; Pei-min WANG
Journal of Nanjing University of Traditional Chinese Medicine 2025;41(2):195-202
OBJECTIVE To explore the intervention mechanism of Shangke Lengtongtie on cold hyperalgesia in KOA mice based on the HMGB1/CXCL12/CXCR4 signaling axis.METHODS Monosodium iodoacetate(MIA)was used for the intra-articular injec-tion into the knee joint to establish mice model of knee osteoarthritis(KOA).Peripheral blood monocytes were extracted from mice,cultured,and then reinfused into the tail vein of the mice.Subsequently,in vivo animal imaging was used to observe the recruitment sites of these monocytes.The cold hyperalgesia threshold was measured at various time points in each group of mice.Hematoxylin and eosin(HE)staining was used to evaluate the level of synovial pathological changes.ELISA was employed to detect the expression of in-flammatory factors IL-1β,TNF-α,and pain mediators CGRP and Substance P in mouse serum.Western blot and qPCR methods were used to detect the protein and gene expression of cold hyperalgesia-related indicators such as TRPA1,TRPM8,HMGB1,CXCL12,CXCR4,Collagen Ⅰ,and Netrin-1 in synovial tissue,as well as DCC in dorsal root ganglia(DRG)tissue.RESULTS In vivo ima-ging showed that after the monocytes were reinfused into KOA mice,they were recruited to the knee joint area,with the HMGB1 group exhibiting a greater recruitment of circulating monocytes at the knee joint.Additionally,compared to the control group,the KOA group and HMGB1 group showed inflammatory pathological changes in the synovium,increased expression of serum inflammatory factors and pain mediators,reduced cold hyperalgesia threshold,and upregulated protein and gene expression of cold hyperalgesia-related indica-tors in synovial and DRG tissues.The changes were more significant in the HMGB1 group compared to the KOA group(P<0.05).Af-ter treatment with Shangke Lengtongtie or GL intervention,synovial inflammation was alleviated,serum inflammatory factors and pain mediators decreased,cold hyperalgesia threshold increased,and the upregulation of cold hyperalgesia-related indicator protein and gene expression levels was significantly reversed(P<0.05).CONCLUSION Shangke Lengtongtie exerts a beneficial effect on the mitigation of synovitis and cold hyperalgesia in KOA mice,a therapeutic mechanism that possibly mediated through the inhibition of the HMGB1/CXCL12/CXCR4 signaling axis.

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