Objective To investigate the self-assembly and cellular localization patterns of fila-mentous temperature-sensitive protein Z (FtsZ) in Escherichia coli (E.coli) strains by using FtsZP74R, FtsZG77D and FtsZA81R mutants.Methods YFP or His labeled FtsZ proteins and the plasmids of FtsZ mu-tants were constructed by using molecular clone and site-directed mutagenesis methods.The targeted proteins were purified by affinity chromatography.FL37(△ftsZ-Cat) strains were constructed via linear DNA homol-ogous recombination.Living cell imaging was performed to observe the cellular localization patterns of FtsZ protein and its mutants in E.coli strains.The interactions between FtsZ-FtsZ/FtsZ mutants were examined by coi-mmunoprecipitation assay . The polymerization properties of FtsZ mutants were analyzed by light scattering.The activities of GTPase were monitored by using high performance liquid chromatography.Re-sults The P74, G77 and A81 amino acids were respectively replaced by different polar amino acids to change the amphipathicity of the helix within the domain of FtsZ ( 74-82 ) .The YFP-labeled FtsZP74R , FtsZG77D and FtsZA81R mutants failed to assemble into functional Z-ring structure in E.coli strains.The inter-actions between FtsZ protein and its mutants were weakened or completely disappeared.In addition, in vitro experiments showed that P74R, G77D and A81R mutations caused a decrease in the polymerization efficien-cy of FtsZ monomer.The activity of GTPase was significantly decreased in the FtsZA81R mutant. Conclusion The P74, G77 and A81 were critical amino acids in the function and assembly of FtsZ protein in E.coli strains.Moreover, A81 amino acid regulated the lateral interaction of FtsZ monomer and the activity of GTPase.

Coronavirus Disease 2019 (COVID-19) is an infectious disease caused by 2019 novel Coronavirus (2019-nCoV). At present, the most used method to diagnose 2019-nCoV is nucleic acid test. Suspected cases underwent real-time fluorescent RT-PCR examination, and those who were 2019-nCoV nucleic acid positive were confirmed cases. However, in the process of nucleic acid test, factors such as specimen quality, specimen transportation and storage conditions, detection reagents and methods may cause false negative or false positive results. This article reviews the factors that may affect the results of 2019-nCoV nucleic acid test, and provides a basis for the diagnosis of suspected COVID-19 cases.

Objective To investigate the causes of infertility and its pathological mechanism in female SD rats with spontaneous dwarfism(short stature rat,SSR).Methods Adult wildtype and SSR female SD rats were used in this study.A vaginal smear was used to observe changes in the motile cycle.Ovulation promotion was compared using the simultaneous estrus supernumerary ovulation method.Ovarian and uterine weight and body weight,and ovarian and uterine indices were measured.AMH,E2,FSH,LH,and FSH/LH levels in serum were measured.Transcriptome sequencing of ovarian tissues was performed to analyze gene expression differences.Results No abnormalities were observed in the estrous cycle of SSR female rats.The body weight of SSR female rats was significantly lower than that of wildtype rats,and their ovarian and uterine indices were significantly higher than that of wildtype rats.The mean number of ovulations was significantly higher in wildtype rats than in SSR female infertile rats(P<0.001).Serum AMH(P<0.01)and E2(P<0.05)levels were significantly higher in wildtype rats than in SSR female infertile rats,and serum levels of FSH,LH,and FSH/LH(P<0.05)were significantly lower in SSR infertile females than in SSR infertile rats,while PROG showed no significant difference.Transcriptome sequencing yielded 250 differentially expressed genes,including 190 upregulated and 60 downregulated genes.p53 signaling pathway and cytokine-cytokine receptor interaction.The MCC,MNC,EPC,and degree calculations of the CytoHubba plug-in were used to screen the top 10 significant nodes.The intersection was used to finally obtain nine hub genes,namely Cxcl1,Cxcl2,IL1a,IL1b,Cd80,Mmp13,Mmp8,Fgf3,and Ptgs2.Conclusions Infertility in SSR female rats may be related to a decreased ovarian reserve function and poor ovarian response.Cxcl1,Cxcl2,IL1a,IL1b,Cd80,Mmp13,Mmp8,Fgf3,and Ptgs2 were associated with infertility,laying a theoretical foundation to further explore infertility mechanisms.

Objective:To establish a risk prediction model for prolonged mechanical ventilation in adult heart transplant recipients.Methods:This study used structured language to query hospital electronic medical record systems. From January 2004 to December 2021, 957 adult recipients undergoing cardiac transplantation at Fuwai Hospital of the Chinese Academy of Medical Sciences were selected as the study subject using a convenience sampling. This study collected basic information, past history, preoperative blood creatinine, preoperative total bilirubin, preoperative ventilation assistance, and intraoperative donor heart cold ischemia time. The enrolled patients were divided into a training group ( n=717) and a validation group ( n=240) in a ratio of 3∶1. Based on the training group data, a risk prediction model was constructed using two-way stepwise Logistic regression. The prediction performance of the model was evaluated using the area under the receiver operating characteristic (ROC) curve, sensitivity and specificity based on the validation group data. Results:A total of 957 adult heart transplant recipients were included, and 18.39% (176/957) of them experienced prolonged mechanical ventilation (>24 hours) after surgery. Based on the model established by the training group data, 7 independent risk factors for prolonged mechanical ventilation after surgery were clarified, including age ≥ 60 years old ( OR=1.820), history of blood transfusion ( OR=5.237), previous cardiac surgery ( OR=2.826), preoperative total bilirubin≥ 34.2 μmol/L ( OR=1.861), preoperative ventilator assistance ( OR=9.421), preoperative intra-aortic balloon pump assistance ( OR=1.826), intraoperative donor heart cold ischemia time≥ 360 min ( OR=2.093) ( P<0.05). The area under the curve of the model was 0.676 (95% confidence interval was 0.581 to 0.770), with a sensitivity of 0.500, and a specificity of 0.796. Conclusions:Based on the data of adult heart transplant recipients from a single center, this study established a relatively simple and objective risk prediction model that can predict the prolonged mechanical ventilation in adult heart transplant recipients, and has good clinical value.

ObjectiveTo investigate the impact of acute respiratory infections in children under 12 years old in Pudong New Area， Shanghai from 2019 to 2023. MethodsAcute respiratory infection samples of children under 12 years old from three sentinel hospitals in Pudong New Area， Shanghai from 2019 to 2023 were collected， and 42 respiratory infection pathogens， including influenza virus， adenovirus， parainfluenza virus， respiratory syncytial virus， human enterovirus/rhinovirus， human pulmonary virus， human bokavirus， coronavirus （229E， HKU1， NL63 and OC43）， and novel coronavirus， were detected with microfluidic chips. The situation of acute respiratory infections among outpatient and inpatient children in this area was analyzed for the before the implementation of non pharmacological intervention measures （2019.12‒2020.1）， during the period of non pharmacological intervention measures （2020.2‒2022.12）， and after non pharmacological intervention measures （2023.1‒2023.6）. ResultsFrom 2019 to 2023， a total of 1 770 samples were collected， and 445 pathogens were detected， with a detection rate of 25.14% （445/1 770）. The main pathogens detected during the study period were influenza virus： 8.70% （154/1 770）， respiratory syncytial virus： 4.41% （78/1 770）， human enterovirus/rhinovirus： 2.66% （47/1 770）， human adenovirus： 2.49% （44/1 770）， and parainfluenza virus： 2.20% （39/1 770）. Before the implementation of non pharmacological intervention measures， outpatients were primarily infected with influenza， parainfluenza virus， and respiratory syncytial virus， with detection rates of 8.09%， 4.49%， and 4.04%， respectively； inpatients were mainly infected with influenza， respiratory syncytial virus， and parainfluenza virus， with detection rates of 4.49%， 3.82%， and 3.15%， respectively. During the period of non pharmacological intervention measures， influenza， rhinovirus and respiratory syncytial virus were the main viruses detected in the samples of outpatient children， with detection rates of 4.04%， 3.60%， and 2.47%， respectively； inpatient samples mainly detected respiratory syncytial virus， rhinovirus， and influenza virus， with detection rates of 3.60%， 2.02%， and 1.80%， respectively. After non pharmacological intervention measures， influenza， rhinovirus and respiratory syncytial virus were the main pathogens detected in the outpatients， with detection rates of 9.89%， 2.92% and 2.02%， respectively； influenza， respiratory syncytial virus， and rhinovirus were the main pathogens detected in inpatient children， with detection rates of 6.29%， 1.57%， and 1.35%， respectively. ConclusionThe prevalence of pathogens related to acute respiratory infections in children is influenced by non pharmacological preventive measures.