Fusobacterium nucleatum-induced imbalance in microbiome-derived butyric acid levels promotes the occurrence and development of colorectal cancer

BACKGROUND Colorectal cancer(CRC)ranks among the most prevalent malignant tumors globally.Recent reports suggest that Fusobacterium nucleatum(F.nucleatum)contributes to the initiation,progression,and prognosis of CRC.Butyrate,a short-chain fatty acid derived from the bacterial fermentation of soluble dietary fiber,is known to inhibit various cancers.This study is designed to explore whether F.nucleatum influences the onset and progression of CRC by impacting the intestinal metabolite butyric acid.AIM To investigate the mechanism by which F.nucleatum affects CRC occurrence and development.METHODS Alterations in the gut microbiota of BALB/c mice were observed following the oral administration of F.nucleatum.Additionally,DLD-1 and HCT116 cell lines were exposed to sodium butyrate(NaB)and F.nucleatum in vitro to examine the effects on proliferative proteins and mitochondrial function.RESULTS Our research indicates that the prevalence of F.nucleatum in fecal samples from CRC patients is significantly greater than in healthy counterparts,while the prevalence of butyrate-producing bacteria is notably lower.In mice colonized with F.nucleatum,the population of butyrate-producing bacteria decreased,resulting in altered levels of butyric acid,a key intestinal metabolite of butyrate.Exposure to NaB can impair mitochondrial morphology and diminish mitochondrial membrane potential in DLD-1 and HCT116 CRC cells.Consequently,this leads to modulated production of adenosine triphosphate and reactive oxygen species,thereby inhibiting cancer cell prolif-eration.Additionally,NaB triggers the adenosine monophosphate-activated protein kinase(AMPK)signaling pathway,blocks the cell cycle in HCT116 and DLD-1 cells,and curtails the proliferation of CRC cells.The combined presence of F.nucleatum and NaB attenuated the effects of the latter.By employing small interfering RNA to suppress AMPK,it was demonstrated that AMPK is essential for NaB’s inhibition of CRC cell proliferation.CONCLUSION F.nucleatum can promote cancer progression through its inhibitory effect on butyric acid,via the AMPK signaling pathway.

Development of Quantitative Real-time Polymerase Chain Reaction for the Detection of Vibrio vulnificus Based on Hemolysin (vvhA) Coding System

Objective To establish a TaqMan real-time fluorescent quantitative PCR to detect Vibrio vulnificus based on the hemolysin gene （vvhA） coding cytolysin. Methods Primers and probes in the conserved region of the vvhA gene sequence were designed for the TaqMan real-time PCR to detect 100 bp amplicon from V. vulnificus DNA. Recombinant plasmid pMD19-vvhA100 was constructed and used as a positive control during the detection. Minimal amplification cycles （Ct value） and fluorescence intensity enhancement （ARn value） were used as observing indexes to optimize the reaction conditions of TaqMan real-time PCR. The TaqMan assay for the detection of Vbirio vulnificus was evaluated in pure culture, mice tissue which artificially contaminated Vibrio vulnificus and clinical samples. Results The established TaqMan real-time PCR showed positive results only for Vibrio vulnificus DNA and pMD19-vvhA100. The standard curve was plotted and the minimum level of the vvhA target from the recombinant plasmid DNA was 103 copies with a Ct value of 37.94±0.19, as the equivalent of 0.01 ng purified genomic DNA of Vibrio vulnificus. The results detected by TaqMan PCR were positive for the 16 clinical samples and all the specimens of peripheral blood and subcutaneous tissue of mice which were infected with Vibrio vulnificus. Conclusion TaqMan real-time PCR is a rapid, effective, and quantitative tool to detect Vibro vulnificus, and can be used in clinical laboratory diagnosis of septicemia and wound infection caused by Vibrio vulnificus.

Usefulness of interferon-γrelease assay for the diagnosis of sputum smear-negative pulmonary and extra-pulmonary TB in Zhejiang Province,China

Background:Quick diagnosis of smear-negative pulmonary tuberculosis(TB)and extra-pulmonary TB are urgently needed in clinical diagnosis.Our research aims to investigate the usefulness of the interferon-γrelease assay(IGRA)for the diagnosis of smear-negative pulmonary and extra-pulmonary TB.Methods:We performed TB antibody and TB-IGRA tests on 389 pulmonary TB patients(including 120 smear-positive pulmonary TB patients and 269 smear-negative pulmonary TB patients),113 extra-pulmonary TB patients,81 patients with other pulmonary diseases and 100 healthy controls.Blood samples for the TB-Ab test and the TB-IGRA were collected,processed,and interpreted according to the manufacturer’s protocol.Results:The detection ratio of smear-positive pulmonary TB patients and smear-negative pulmonary TB patients were 90.8%(109 of 120)and 89.6%(241 of 269),respectively.There was no statistically significant difference of its performance between these two sample sets(P>0.05).The detection ratio of positive TB patients and extra-pulmonary TB patients were 90.0%(350 of 389)and 87.6%(99 of 113),respectively,which was not significantly different(P>0.05).Conclusions:In this work,the total detection ratio using TB-IGRA was 89.4%,therefore TB-IGRA has diagnostic values in smear-negative pulmonary TB and extra-pulmonary TB diagnosis.

Circulating MicroRNAs as Potential Biomarkers in the Diagnosis of Neurosyphilis: A Case Control Study

Objective:Laboratory diagnosis of neurosyphilis(NS)remains a great challenge.This study was the aimed to identify miRNA candidates as biomarkers to distinguish between NS,non-neurosyphilis,and healthy controls(HCs).Methods:We analyzed miRNA expression profiles in peripheral blood mononuclear cells(PBMCs)from six patients with NS,eight patients with secondary syphilis(SS),and five HCs using microarray technology.The differentially expressed miRNAs were validated in 33 NS samples,31 SS samples,and 30 HC samples using TaqMan miRNA real-time qPCR(qRT-PCR).Results:Thirty-nine miRNAs were differentially expressed in SS and NS patients compared with HCs.Thirteen miRNAs were randomly selected to validate their expression levels in the same samples used in microarray assay by qRT-PCR.All miRNAs were upregulated in SS and NS samples compared with HC.qRT-PCR analysis of the expression of the 13 miRNAs in a second cohort(76 samples)showed that the average expression levels of nine miRNAs were higher in SS than in NS(SS:0.185,NS:0.136,P=3.8E-10),while the expressions of the other four miRNAs were lower in SS than in NS(SS:0.000757,NS:0.000873,P=0.022).ROC curve analysis of the 13 miRNAs showed the area under the curve value to be 1.00 for distinguishing SS patients from HCs,1.00 for distinguishing NS patients from HCs,1.00 for distinguishing SS and NS patients from HCs,and 0.968 for distinguishing NS from SS patients.Conclusion:The present study is the first one that identified differentially expressed miRNAs in PBMCs from patients with NS.Our results suggest that the 13 candidate miRNAs in PBMCs may be novel noninvasive biomarkers for NS diagnosis.

Quorum Sensing:An Emerging Role for Vibrio Infection and Host Defense

Quorum sensing(QS)is a mechanism that allows bacteria to regulate various physiological and biochemical functions by secreting,sensing and responding to signaling molecules called autoinducers(AIs).In Vibrio species,QS plays a crucial role in modulating different biological characteristics.QS can influence the formation of biofilms,which are communities of bacteria encased in a protective matrix.It also controls flagella formation and motility,ensuring that Vibrio spp.can move efficiently in response to environmental cues.Additionally,QS in Vibrio spp.regulates the production of different virulence factors based on cell density.This enables the bacteria to adjust their virulence strategies accordingly,enhancing pathogenicity.QS also influences the interaction between Vibrio spp.and their host.Following infection by Vibrio spp.,QS can affect the host immune response and colonization processes.Understanding the role of QS in these interactions is crucial for unraveling the complex dynamics between Vibrio spp.and the host.In summary,research on QS in Vibrio spp.has revealed its significance in regulating various biological phenotypes,controlling virulence factor production and affecting host defense.It provides valuable insights into the intricate mechanisms underlying microbial behavior,host adaptation and Vibrio spp.pathogenesis.