SARS-CoV-2合并感染患者的病原微生物分布特征及耐药性分析

目的分析严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2,SARS-CoV-2)合并感染患者病原微生物分布特点及耐药情况,为临床诊治提供依据。方法收集2022年12月至2023年2月延安大学附属医院收治的2019冠状病毒病(corona virus disease 2019,COVID-19)患者637例的临床资料,回顾性分析其临床特征及合并感染病原微生物情况。结果COVID-19患者以老年人为主,合并基础疾病患者占79.59%,好转及痊愈患者高达91.05%。培养阳性标本来源于呼吸道、血液和尿液,合并感染的病原微生物分别以肺炎克雷伯杆菌、凝固酶阴性葡萄球菌(coagulase negative staphylococci,CNS)和真菌为主。药敏试验结果显示,肺炎克雷伯杆菌对β内酰胺类抗生素及三代、四代头孢菌素类抗生素耐药率较低(14%~20%),鲍曼不动杆菌对氨基糖苷类抗生素和β内酰胺类复合物较为耐药(均>45%),大肠埃希菌对β内酰胺类抗生素及其复合物耐药率较低(14%~19%)。金黄色葡萄球菌、CNS、屎肠球菌、粪肠球菌均未发现对万古霉素、利奈唑胺、替加环素耐药。结论COVID-19合并感染病原体以革兰阴性菌及真菌为主,感染部位以呼吸道为主,主要病原菌为肺炎克雷伯杆菌。鲍曼不动杆菌对氨基糖苷类抗生素和β内酰胺类复合物耐药率高于全国细菌耐药平均水平,提示临床上应根据COVID-19患者的微生物鉴定和药敏试验结果,选择对症药物治疗,以改善患者预后。

SARS-CoV-2靶向CypA/CD147受体途径诱导心肌细胞凋亡

目的探究SARS-CoV-2靶向亲环素A(CypA)/细胞外金属蛋白酶诱导剂(CD147)受体途径诱导心肌细胞凋亡的可能机制。方法构建pEncmv-SARS-CoV-2 S-3xflag重组载体质粒转染H9c2细胞,TUNEL实验、流式细胞术和DNA ladder分析细胞凋亡,免疫共沉淀(CoIP)验证CD147与SARS-CoV-2 S蛋白之间相互作用,Western blotting法检测细胞凋亡信号通路相关蛋白表达。结果与对照组比较,TUNEL实验和流式细胞术结果显示转染组细胞凋亡显著增加(P<0.05),DNA ladder分析发现DNA降解明显。Western blotting法检测显示Caspase12、DR3表达显著升高(P<0.001),FAS表达升高(P<0.01),TRF1、DR4表达降低(P<0.01)。结论SARS-CoV-2 S蛋白靶向CypA/CD147受体入侵宿主细胞,激活内质网通路(Caspase12)和死亡受体通路(DR3、FAS),以内源性和外源性凋亡途径诱导心肌细胞凋亡。

自然杀伤(NK)细胞与2019冠状病毒病(COVID-19)发生发展的研究进展

自然杀伤(NK)细胞在清除病毒,执行免疫调节方面发挥着重要的作用,它通过分泌趋化因子以及与其他天然免疫细胞协同作用,被赋予天然免疫调节功能和获得性免疫反应。随着对严重急性呼吸综合征冠状病毒2(SARS-CoV-2)感染的2019冠状病毒病(COVID-19)的研究深入,发现NK细胞在其中发挥着重要作用。SARS-CoV-2感染会影响NK细胞的分布和效应功能,NK细胞的免疫应答或可影响新冠肺炎患者的预后。本文总结了近年来NK细胞在COVID-19感染中作用的研究现状,并且讨论了以NK细胞作为治疗剂的可能性,以期为防治SARS-CoV-2的免疫损害提供潜在思路。

槲皮素通过抑制ACE2治疗SARS-CoV-2所致心肌损伤的研究进展

2019年底,由重症急性呼吸道综合征冠状病毒2(SARS-CoV-2)引起的新型冠状病毒病肺炎(COVID-19)在全球迅速蔓延,由于其潜伏期长、传播性强、突变率高,因此,COVID-19的防治已成为全球卫生领域的焦点问题。由于人体呼吸道黏膜表面血管紧张素转换酶2(angiotensin converting enzyme 2,ACE2)含量丰富,而SARS-CoV-2表面的刺突蛋白(S蛋白)具有介导受体识别和结合功能,其受体结构域可特异性结合ACE2的肽酶结构域。因此,ACE2是作为SARS-CoV-2感染的宿主的途径,在SARS-CoV-2感染机体过程中发挥至关重要的作用。与此同时,心肌组织ACE2含量较丰富,且COVID-19合并心肌损伤患者心肌组织ACE2呈现表达异常。而我国传统中医药六大处方防治COVID-19疗效显著,其中,共有中药单体成分槲皮素备受关注,防治机制可能与槲皮素抑制ACE2密切相关。迄今为止,少有SARS-CoV-2所致心肌损伤药物治疗的相关报道。因此,本文旨在通过文献汇总和生信预测探讨槲皮素是否通过抑制ACE2在心肌组织中的高表达从而改善COVID-19所致心肌损伤,从而降低COVID-19患者心源性死亡率及心血管并发症。

核酸检测Ct值在COVID-19重症风险预测模型构建的应用价值研究

目的验证荧光PCR测量的循环阈值(Ct值)对COVID-19患者重症风险评估的应用价值,并结合其它生化指标构建一个预测模型。方法通过对山东大学附属威海市立医院236例COVID-19住院患者的回顾性分析(2022年12月至2023年5月),收集病毒核酸检测Ct值及常规检验指标。利用Logistic回归分析筛选影响重症风险因素,并构建预测模型。采用受试者工作特征曲线(ROC)和临床决策曲线(DCA)评估模型性能,并量化Ct值的贡献度。结果年龄、白细胞计数、血小板、血红蛋白升高与重症风险正相关;较高的首次核酸检测阳性Ct值与重症风险负相关。COVID-19重症肺炎风险预测模型提示,年龄较大、PLT和WBC水平较高,以及Ct值和HGB较低的患者,重症化的风险显著增加。模型拟合度良好,AIC、C-index、R2和霍斯默检验的P值分别为126.00、0.90、0.51和0.53。相较仅含临床指标的模型,含Ct值的模型的ROC下面积(AUC)值在训练集和验证集分别从0.84和0.89提升至0.93和0.97,灵敏度从0.71和0.78增加为0.86和1.00,特异度从0.82和0.87上升到0.87和0.92。DCA结果验证了组合模型的临床应用价值。结论Ct值是评估COVID-19患者重症风险的重要指标,本研究所构建的预测模型为患者的早期诊治提供了创新且有效的工具。

糖尿病患者接种SARS-Cov-2疫苗后的免疫反应:系统评价

目的系统评价糖尿病患者在接种SARS-CoV-2疫苗后的体液和细胞免疫反应。方法检索Web of Science、PubMed、中国知网、万方数据知识服务平台、维普中文科技期刊全文数据库和中国生物医学文献数据库,获取国内外于2019年12月1日至2022年5月12日公开发表的有关糖尿病患者接种SARS-CoV-2疫苗后的体液和细胞免疫反应的观察性研究,经由2名研究者独立筛选文献和提取资料后,采用美国国立卫生研究质量评价工具对纳入文献进行偏倚风险评价,使用描述性统计方法进行汇总分析。结果13篇文献共纳入66651例研究对象,其中5874例(7.9%)患有糖尿病。7篇文献报道了接种第1剂疫苗后糖尿病患者和对照组的免疫反应,其中3篇文献表明,接种1剂SARS-CoV-2疫苗后,糖尿病患者血清抗体水平和阳性率低于对照组;11篇涉及接种2剂SARS-CoV-2疫苗后的免疫反应的文献中,2篇报道了糖尿病患者可产生与对照组相似的抗体反应,9篇报道了糖尿病患者的血清抗体水平、阳性率或细胞免疫反应低于对照组。结论接种SARS-CoV-2疫苗后糖尿病患者和对照组体液和细胞免疫反应均有所增加,但糖尿病患者增加幅度普遍低于对照组。

基于hACE2转导建立SARS-CoV-2 spike假病毒感染病证结合的小鼠病毒肺炎模型

目的建立与评价一种安全、经济、有效的病证结合小鼠新冠病毒感染肺炎模型。方法30只KM种小鼠随机分为空白组、对照组及实验1组、实验2组、实验3组,每组各6只。每天把KM小鼠置于模拟寒湿环境中4 h,将表达hACE2的重组腺相关病毒(pAAV-hACE2)采用改良悬挂法气管内给药转导至肺组织,继以新型冠状病毒(SARS-CoV-2)spike假病毒采用相同的气管内给药方式造模。观察各组小鼠一般情况,检测体重变化、肺指数、血清炎性因子及肺部病理变化。结果免疫组化法显示h ACE2在小鼠肺组织中有效表达;在寒湿环境中给予SARS-CoV-2 spike假病毒后,实验组小鼠表现出类似疫毒犯肺证候的体征;且同样喂养条件和时间下,与空白组和对照组小鼠比较,实验组小鼠出现体重下降;实验1、2、3组小鼠出现肺指数显著增大(P<0.05或P<0.01),血清炎性因子白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)显著升高(P<0.01),肺组织病理改变明显。结论本研究成功建立了一种安全、经济、有效的病证结合小鼠新冠病毒感染肺炎模型。

hiPSCs分化的细胞和类器官在SARS-CoV-2感染研究上的应用

SARS-CoV-2引起全球性传染病COVID-19的大流行,SARS-CoV-2感染研究对于了解人体细胞和器官被此种病毒感染后的病理反应具有重要意义。将hiPSCs分化为呼吸道、肺类器官、神经系统细胞、脑类器官、心肌细胞、血管、肠类器官和肾类器官,进行SARS-CoV-2感染研究,发现这些细胞和类器官受SARS-CoV-2感染,生理活性受损,生理功能削弱,促炎性因子分泌增加,类器官发生炎症反应和功能退化现象。因此,hiPSCs分化的细胞和类器官可用于SARS-CoV-2感染研究,病毒感染会影响这些细胞和类器官的功能。

Seroprevalence of SARS-COV-2 Exposure among “High-Risk” Populations (Healthcare Workers, People Who Attend Markets, and School Children) in Zanzibar

In Zanzibar, from the start of the pandemic in March 2020 to the time of sampling in December 2020, SARS-CoV-2 seroprevalence data was limited. We conducted a seroprevalence study to evaluate the magnitude of SARS-CoV-2 exposure among healthcare workers, school children, and people who attended general markets in Zanzibar. The objectives of the study were to analyse the total antibodies from selected higher-risk population groups in order to determine magnitude in SARS CoV-2 exposure. Blood samples were collected from eligible and consented participants (adults and children), and their serum was analyzed for total antibodies against SARS-CoV-2 using ELISA. A questionnaire was used to collect participants’ demographic and clinical data. The overall SARS-CoV-2 seroprevalence across all age groups was 33%, and a higher seroprevalence was observed in the 40 - 49 years’ age group relative to other ages as well as in those who attended markets. A runny nose (18.8% of participants) was the most frequently reported SARS-CoV-2 infection-related symptom. Multivariable analysis showed significantly higher odds of infection in people living in urban districts. The findings provide insight into SARS-CoV-2 infection among school children, health workers, and people who attended markets in Zanzibar in the early stages of the pandemic. Exposure in these groups might have been influenced by infection and prevention strategies taken by the government, as well as shopping behavior, school overcrowding, and population density in urban settings. The study had methodological limitations, including cross-sectional design. Further, well-designed, longitudinal studies are recommended to understand exposure and transmission at a population level.

Genomic Profile of SARS-COV-2 Associated with COVID-19 Outbreaks in N’Djamena, Chad

Background: SARS-CoV-2 has circulated worldwide with dramatic consequences. In Chad, we have no data reported of variants. The aim of this study was to identify the SARS-CoV-2 variants that circulated during the epidemic from 2020 to 2021. Methods: This is a cross-sectional, descriptive study carried out between 2020 and 2021. Samples from patients with suspected COVID-19 were tested in five laboratories in N’Djamena. One hundred quality samples of the positives were sequenced in Kinshasa using Oxford nanopore technologies minion and the Protocol Midnight SARS-CoV2. Data were processed using Excel version 16 software. Results: Of the 100 samples sequenced, 77 (77%) produced sequences, 23 (23%) did not. The genomic profiles were wild-type Wuhan and minor mutations (19A, 19B (A), 20A (B.1, B.2), 20B (AV.1), 20D (B.1.1.1 /C.36), 20C), variant of concern Alpha (20I), variant of concern Delta (21A/J), variant of interest Eta (21D), variant of concern Omicron (21K) and unclassified variant under surveillance (B.1.640). Of these variants, the maximums were detected in patients aged 26 - 35 with 30.26% and 25.26% in 36 - 45. However, 24.67% were in travelers and 75.32% in residents, 35.06% in those vaccinated against COVID-19 and 62.33% in non-vaccinates. The estimated case-fatality rate was 2.44% (107/4374). Conclusion: This work has provided preliminary data on COVID-19 and SARS-CoV-2 variants circulating during the 2020-2021 epidemics in Chad.

Evaluation of a Rapid Diagnostic Test, Boson Biotech SARS CoV-2 Ag, for the Detection of SARS-CoV-2 in Gabon

1) Background: Rapid and acurate diagnostic testing for case identification, quarantine, and contact tracing is essential for managing the COVID 19 pandemic. Rapid antigen detection tests are available, however, it is important to evaluate their performances before use. We tested a rapid antigen detection of SARS-CoV-2, based on the immunochromatography (Boson Biotech SARS-CoV-2 Ag Test (Xiamen Boson Biotech Co., Ltd., China)) and the results were compared with the real time reverse transcriptase-Polymerase chain reaction (RT-PCR) (Gold standard) results;2) Methods: From November 2021 to December 2021, samples were collected from symptomatic patients and asymptomatic individuals referred for testing in a hospital during the second pandemic wave in Gabon. All these participants attending “CTA Angondjé”, a field hospital set up as part of the management of COVID-19 in Gabon. Two nasopharyngeal swabs were collected in all the patients, one for Ag test and the other for RT-PCR;3) Results: A total of 300 samples were collected from 189 symptomatic and 111 asymptomatic individuals. The sensitivity and specificity of the antigen test were 82.5% [95%CI 73.8 - 89.3] and 97.9 % [95%CI 92.2 - 98.2] respectively, and the diagnostic accuracy was 84.4% (95% CI: 79.8 - 88.3%). The antigen test was more likely to be positive for samples with RT-PCR Ct values ≤ 32, with a sensitivity of 89.8%;4) Conclusions: The Boson Biotech SARS-CoV-2 Ag Test has good sensitivity and can detect SARS-CoV-2 infection, especially among symptomatic individuals with low viral load. This test could be incorporated into efficient testing algorithms as an alternative to PCR to decrease diagnostic delays and curb viral transmission.

Isolation and Characterization of SARS-CoV-2 in Kenya

The discovery of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) in Wuhan, Hubei province, China, in December 2019 raised global health warnings. Quickly, in 2020, the virus crossed borders and infected individuals across the world, evolving into the COVID-19 pandemic. Notably, early signs of the virus’s existence were observed in various countries before the initial outbreak in Wuhan. As of 12th of April, the respiratory disease had infected over 762 million people worldwide, with over 6.8 million deaths recorded. This has led scientists to focus their efforts on understanding the virus to develop effective means to diagnose, treat, prevent, and control this pandemic. One of the areas of focus is the isolation of this virus, which plays a crucial role in understanding the viral dynamics in the laboratory. In this study, we report the isolation and detection of locally circulating SARS-CoV-2 in Kenya. The isolates were cultured on Vero Cercopithecus cell line (CCL-81) cells, RNA extraction was conducted from the supernatants, and reverse transcriptase-polymerase chain reaction (RT-PCR). Genome sequencing was done to profile the strains phylogenetically and identify novel and previously reported mutations. Vero CCL-81 cells were able to support the growth of SARS-CoV-2 in vitro, and mutations were detected from the two isolates sequenced (001 and 002). Genome sequencing revealed the circulation of two isolates that share a close relationship with the Benin isolate with the D614G common mutation identified along the S protein. These virus isolates will be expanded and made available to the Kenya Ministry of Health and other research institutions to advance SARS-CoV-2 research in Kenya and the region.

Impact of the COVID-19 Pandemic on Cancer Patients: Experience of the medical oncology department of CHU HASSAN II Fez.

Introduction: In December 2019, COVID 19 spread worldwide, but did not officially start in MOROCCO until March 02, 2020. Since then, this pandemic has significantly impacted the health status of patients in general and cancer patients in particular. The main objective of our study is to evaluate the prognosis of patients treated for cancer and infected with COVID-19. Material and method: A descriptive study with prospective collection was carried out at the medical oncology department of CHU Hassan II in FEZ over a period of two years, from March 2020 to March 2022. Data was carried out on the software SPSS. Results: One hundred cancer patients tested positive for COVID-19 infection and were collected within our department. The average age was 56 years [22-91]. The sex ratio was 1.2. Patients with breast cancer were the most affected by this infection (34%). The clinical symptomatology was dominated by the respiratory syndrome (45%).The diagnosis was made through thoracic CT scan in 62% of cases. 76% of patients were in a metastatic stage. 96% of patients were undergoing oncological treatment. For symptomatique patients, the standard treatment approach involved using antibiotics in 76% of cases. Evolution was marked by recovery in 79% of patients, with a death rate of 12% in this cancer patient population. Conclusion: COVID-19 infection is particularly severe in cancer patients. Mortality among these patients remains high and is associated with overall patient characteristics. However, anticancer treatments have not shown deleterious effects on the course of COVID-19.

Leveraging Nanotechnology for Addressing COVID-19: Revealing Antiviral Approaches and Hurdles

The emergence of COVID-19 has caused extensive harm and is recognized as a significant threat to human life worldwide. Currently, the application of nanomedicine techniques in pre-clinical studies related to various infections, such as respiratory viruses, herpes viruses, human papillomavirus, and HIV, has demonstrated success. Nanoparticles, due to their specific attributes, have garnered considerable attention in combating COVID-19. Strategies employing nanomaterials for COVID-19 prevention encompass the development of rapid, precise diagnostic tools, the creation of effective disinfectants, the delivery of mRNA vaccines to the biological system, and the administration of antiretroviral medications within the body. This article focuses on recent research regarding the effectiveness of nano platforms as antiviral measures against coronaviruses. It delves into the molecular characteristics of coronaviruses and the affected target systems, highlighting challenges and limitations in combating SARS-CoV-2. Additionally, it explores potential nanotechnology-based treatments to confront current and future variants of coronaviruses associated with COVID-19 infections.

Impact of a Mass Campaign on the Evolution of the Fourth Wave of the Covid-19 Pandemic in the Central African Republic

Objective: In the context of increasing cases despite vaccination campaigns, a survey was conducted in the Bangui population from January 17 to 26, 2022, to evaluate the strains of Severe Acute Respiratory Infection Coronavirus 2 (SARS-Cov-2) circulating in a healthy population. Materials and methods: This study was conducted by taking nasopharyngeal samples from randomly selected volunteers. Antigen detection was performed systematically, and RT-PCR was done on the positive samples. Results and discussion: We collected 2,554 samples. Thirty were found RT-PCR positive (1.2%) and sent for viral genome sequencing. Twenty-eight SARS-Cov-2 strains belonged to the Omicron type, and only 2 to the Delta type. Conclusion: Thus, infections were uncommon in the tested population, but the presence of Omicron and Delta types raises concerns that vaccination may not be effective in fighting the virus, and newly designed vaccines should be implemented to better protect the population at risk of infection and reinfection by these variants.

Symptomatic COVID-19 in University Students: A School-Wide Web-Based Questionnaire Survey during the Omicron Variant Outbreak

Aim: To detect risk and preventive factors associated with the Omicron variant infection in university students, a combination of a web-based survey and multivariate logistic regression analysis was introduced as the front-line initiatives by the school health practitioners. Design: Questionnaire survey. Methods: The school-wide web-based questionnaire survey was conducted among our university students as a part of the annual health check-up in April, 2023. The positive outcome was confined to the first symptomatic COVID-19 onset during the Omicron variant outbreak. Results: In this self-administered survey, risk or protective associations were merely estimated statistically in university students (n = 5406). In measured factors, karaoke and club/group activities could maintain the statistical significance in adjusted odds ratios (ORs) as relative risk factors, and science course, measles/ rubella (MR) vaccination, and COVID-19 vaccination remained as relative protective factors in adjusted OR analyses. Club/group activities with member gathering and karaoke sing-along sessions in university students may frequently have WHO’s three Cs. These risk factors are still important topics for the infection control of COVID-19 in university students. Together with some recent reports from other researchers, the significant protective role of MR vaccine in our survey warrants further clinical investigation. If the breakthrough infection continuously constitutes the majority of infection, real data in test-negative case-control or web-based questionnaire design continue to be important for statistical analysis to determine the minimal requirement of our strategies which may be equivalent to or replace COVID-19 vaccines.

Comparison of Oral Manifestations in Hospitalized COVID-19 Positive Patients and COVID-19 Negative Dental Outpatients. A Case Series Study and Literature Review

Background: The Coronavirus disease 2019 (COVID-19) is a respiratory infectious disease, also named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which can cause various systemic manifestations that pose a threat to human life. Oral lesions in patients with COVID-19 may appear during or after the illness and may or may not be a consequence of the viral infection. Objective: In this case series we compare the oral manifestations in hospitalized COVID-19 positive patients and COVID-19 negative dental outpatients. Methods: 60 hospitalized COVID-19 patients and 41 control patients, were examined for oral signs and symptoms. The controls were dental patients who visited the hospital for dental care without complaining of any problems related to the oral cavity itself. Results: We have observed a strong association between certain clinical findings and COVID-19, including alterations in taste (ageusia, dysgeusia, and hypogeusia), anosmia, hairy tongue, tongue imprints, red tongue, erythematous candidiasis, pseudomembranous candidiasis, and exfoliative cheilitis. A trend but not statistically significant association at the level of 5% was also noted for colored tongue, linea alba, and pale mucosa. On the contrary, fissured tongue and oral mucosa pigmentation were more frequent in the controls, statistically significant at the level of 5%. Conclusion: COVID-19 has been found to impact the oral cavity, resulting in various oral lesions that can be attributed to either the direct action of the virus or the patient’s immune response.

SARS-CoV-2重组痘苗病毒疫苗rVTT△TK-RBD的构建、筛选及免疫原性研究

目的 构建重组痘苗病毒载体疫苗rVTT△TK-RBD,并评价其安全性和免疫原性。方法 参考严重急性呼吸综合征冠状病毒2(SARS-CoV-2)基因序列合成受体结合域(RBD)基因,并将其插入自主构建的重组质粒pSTKE的多克隆位点上,构建重组痘苗病毒穿梭载体pSTKE-RBD,并转染到预先感染天坛株痘苗病毒(VTT)的BHK-21细胞内,经多轮的荧光噬斑筛选成功获得重组痘苗病毒rVTT△TK-RBD;通过滴鼻方式免疫小鼠后,检测rVTT△TK-RBD对BALB/c小鼠体质量的影响;通过肌肉免疫小鼠后,分析rVTT△TK-RBD对BALB/c小鼠产生的特异性抗体和中和抗体的水平;通过流式细胞术检测rVTT△TK-RBD对BALB/c小鼠T细胞亚群的影响。结果 利用同源重组、增强型绿色荧光蛋白(EGFP)筛选标记和多次荧光噬斑筛选,成功筛选获得了表达RBD的胸腺激酶(TK)基因缺失型重组痘苗病毒rVTT△TK-RBD,且PCR验证成功。BALB/c小鼠体内实验表明rVTT△TK-RBD具有较好的抗SARS-CoV-2的免疫原性且相比于亲本株VTT明显降低了对机体的毒性作用。结论 成功构建并获得SARS-CoV-2重组痘苗病毒疫苗rVTT△TK-RBD并通过各项试验证明其安全性和免疫原性。

重组SARS-CoV-2 Omicron变异株S1蛋白的表达及免疫原性评价

目的构建表达新型冠状病毒(SARS-CoV-2)Omicron BA.1变异株S1蛋白的真核表达载体,在CHO-K1细胞中进行表达,评价其免疫原性,并对佐剂和抗原剂量进行研究。方法构建重组质粒UCOE-Omi-S1,转染至CHO-K1工程细胞中进行表达和纯化,通过SDS-PAGE和Western blot法实验鉴定重组S1蛋白。将BALB/c小鼠随机分为12组,即PBS组,无佐剂组(高、中、低剂量组),铝盐佐剂对照组,MF59佐剂对照组,铝盐佐剂实验组(高、中、低剂量组),MF59佐剂实验组(高、中、低剂量组),将按照分组要求配比的溶液经小鼠肌内注射3次,间隔14天,每2周尾静脉采血,末次免疫30天后取血分离血清,酶联免疫吸附试验(enzyme-linked immunosorbent assay,ELISA)检测血清抗体水平,并和SARS-CoV-2原型株的假病毒和SARS-CoV-2 Omicron BA.1变异株的假病毒进行假病毒中和实验。结果目的蛋白在CHO-K1工程细胞表达后可分泌到培养上清中,在相对分子质量约为70kDa处可见1条特异性蛋白表达条带,经Western blot法鉴定为Omi-S1蛋白。铝盐佐剂组和MF59佐剂组免疫诱导效果优于无佐剂组,铝盐佐剂组和MF59佐剂组免疫诱导效果相差不大,但MF59佐剂起效快;高、中、低剂量组的免疫诱导效果在第8周相差不大,但高剂量组起效快。假病毒中和实验表明,MF59佐剂实验组针对Omicron变异株的中和抗体水平高于铝盐佐剂组。结论本研究所构建的Omicron S1重组蛋白免疫原性良好,在小鼠体内产生了良好的体液免疫应答,并诱导高水平的对抗SARS-CoV-2假病毒的中和抗体,对佐剂和抗原剂量初步研究,结果显示,10μg以下抗原剂量搭配MF59佐剂可获得较好的免疫效果。本研究为SARS-CoV-2变异株的重组蛋白疫苗的研制提供了实验基础。

基于Cov‑AHP的EES系统指标体系构建及对人兽冲突影响测度

在野生动物及其栖息地保护的进程中,人兽冲突事件时有发生,探究人兽冲突的影响因素并提出相应建议是促进人与自然和谐共生的必然要求。本研究以北京市周边地区2009—2017年经济、生态和社会系统(EES系统)的22个变量入手,基于协方差-层次分析法(Cov‑AHP)建立了EES系统指标评价体系。为了探究EES系统中人兽冲突的影响因素,建立多元线性回归模型,运用AIC准则筛选并分析对人兽冲突具有显著影响的变量。结果显示:北京市周边地区人兽冲突形式主要表现为损毁农田和果园,受损失最小的是平谷区,最大的是门头沟区和延庆区,冲突高峰期为每年的8—9月。经济系统中,第二产业增长率、第二产业占比、政府一般预算收入、粮食总产量的增长会加剧人兽冲突的损失;生态系统中,退耕造林面积越大、距水系距离越近,越容易造成人兽冲突损失,而距林地距离越近,越不容易造成人兽冲突损失;社会系统中,恩格尔系数、公共图书馆总藏量会加剧人兽冲突的损失,而防护措施占比则相反。因此,在发展经济的同时,应当优化当地的产业结构,加强生态文明建设,提高当地居民对野生动物及栖息地保护的认知。在推进退耕还林工程的过程中,应该合理地恢复当地的生态环境,避免矫枉过正,与野生动物和谐相处,并建立健全防护措施,减少野生动物对人类带来的负面影响。本研究侧重在EES复合系统中探究人兽冲突的主要影响因素,为减少人兽冲突的损失,促进人与自然和谐共生提供理论依据和数据支持。