基于生物信息学的甲型流感病毒跨物种传播机制的研究——以H7N9为例

以甲型流感病毒（IAV）毒株的完整内部蛋白编码基因为基础,发现并分析IAV传播过程中出现的影响宿主嗜性类型的单个或相互作用的关键氨基酸位点,为研究IAV的人类宿主适应性突变提供依据。

在全球流感共享数据库（GISAID）EpiFlu^TM数据库中,根据查询条件获得43 671个IAV毒株对应的6个内部基因节段全长核苷酸序列,通过质控与去冗余后保留698个嗜人类亚型（HU）和1 266个嗜禽类亚型（AV）代表株,使用R代码比较2种嗜性类别代表株的氨基酸共义序列,获得氨基酸差异位点及其多态性,并对差异位点进行多位点组合分析。

AV与HU中H1N1、H3N2亚型代表株分别进行共有序列比对,各发现49个、57个保守差异位点。差异位点的多位点组合分析,在HU与AV间分别发现79个三位点组合与65个四位点组合。共有11个保守差异位点同时存在于2种组合内：PB2蛋白的271、684位点;PB1蛋白的336、486、581、621位点;PA蛋白的204、356位点;NP蛋白的33、305、357位点;M1和NS1中未发现符合条件的差异位点。

IAV的嗜人和嗜禽类毒株间在PB2、PB1、PA与NP蛋白中存在若干保守氨基酸差异位点,这些位点彼此间可能存在一定形式的互相作用并进而形成特定的组合,共同（而非各自）决定着病毒的宿主嗜性。

     

Community‐based health literacy focused intervention for cervical cancer control among Black women living with human immunodeficiency virus: A randomized pilot trial

BackgroundHealth literacy plays an essential role in how individuals process health information to make decisions about health behaviours including cancer screening. Research is scarce to address health literacy as a strategy to improve cancer screening participation among women living with human immunodeficiency virus (HIV), particularly Black women who, despite the heavy burden of cervical cancer, report consistently low screening rates.AimTo assess the feasibility, acceptability and preliminary efficacy of a health literacy‐focused intervention called CHECC‐uP—Community‐based, HEalth literacy focused intervention for Cervical Cancer control—among women living with HIV.MethodsWe conducted a community‐based, single‐blinded randomized pilot trial. A total of 123 eligible women were enrolled and randomized to one of two conditions, control (i.e., cervical cancer brochure) or intervention (cervical cancer brochure plus 30–60 min health literacy‐focused education followed by monthly phone counselling and navigation assistance for 6 months). Study assessments were done at baseline, 3 and 6 months. The final analysis sample included 58 women who completed all data points and whose Papanicolaou (Pap) test status was confirmed by medical records.ResultsAll intervention participants who completed the programme would recommend the CHECC‐uP to other women living with HIV. However, adherence in the experimental conditions was low (49.6% attrition rate including 20 women who dropped out before the intervention began) due, in large part, to phone disconnection. Those who had received the intervention had a significantly higher Pap test rate compared to women in the control group at 6 months (50% vs. 21.9%, p = .025). Participation in the intervention programme was associated with improved health literacy and other psychosocial outcomes at 3 months but the trend was attenuated at 6 months.ConclusionsThe CHECC‐uP was highly acceptable and led to improved Pap testing rates among Black women living with HIV. Future research should consider addressing social determinants of health such as phone connectivity as part of designing a retention plan targeting low‐income Black women living with HIV.ImplicationsThe findings should be incorporated into a future intervention framework to fulfil the unmet needs of Black women living with HIV to facilitate their decision‐making about Pap test screening.Patient or Public ContributionNineteen community members including women living with HIV along with HIV advocates and care providers participated in four focus groups to develop cervical cancer screening decision‐relevant information and the health literacy intervention. Additionally, a community advisory board was involved to provide guidance in the general design and conduct of the study.     

新疆地区回族、汉族人群 HBV 基因型的分布与特点

目的 了解新疆地区回族、汉族慢性乙型肝炎患者 HBV 基因型分布特点,完善新疆少数民族地区 HBV 流行病学资料。方法对来自乌鲁木齐和伊犁地区的回族与汉族乙型肝炎患者共 194 例,收集血清样本,应用 ELISA 法检测乙肝五项,测序方法进行 HBV 基因分型,荧光定量 PCR 法检测 HBV 基因载量。结果 94 例回族患者中各基因型比例分别为：B 型 7 例占 7.44%,C 型 66 例占 70.21%,D 型 21 例占 22.34%。100 例汉族患者中各基因型比例分别为：B 型 23 例占 23%,C 型 57 例占 57%,D 型 12 例占12%,B/C 混合型 8 例占 8%。汉族和回族中均以 C 型占优势,但 4 种基因型在汉族和回族中的总体分布不同：C 型和 D 型在回族的分布频率大于汉族（P=0.004 和 P=0.002),而 B 型和混合型在汉族中的分布频率大于回族（P=0.003 和 P=0.007）。HBV 基因载量测定检测结果显示,回、汉两民族间 D 基因型在 HBV-DNA 拷贝数上有显著差异（P<0.05）,其他型别均无统计学意义。结论 HBV 的 4 种基因型在汉族和回族中总体分布不同,两民族 C 型都占有绝对优势,但基因类型构成又各具特点,体现了新疆地区 HBV 基因型的地域分布和族群分布特点。     

Functional polyamine metabolic enzymes and pathways encoded by the virosphere

Viruses produce more viruses by manipulating the metabolic and replication systems of their host cells. Many have acquired metabolic genes from ancestral hosts and use the encoded enzymes to subvert host metabolism. The polyamine spermidine is required for bacteriophage and eukaryotic virus replication, and herein, we have identified and functionally characterized diverse phage- and virus-encoded polyamine metabolic enzymes and pathways. These include pyridoxal 5′-phosphate (PLP)-dependent ornithine decarboxylase (ODC), pyruvoyl-dependent ODC and arginine decarboxylase (ADC), arginase, S-adenosylmethionine decarboxylase (AdoMetDC/speD), spermidine synthase, homospermidine synthase, spermidine N-acetyltransferase, and N-acetylspermidine amidohydrolase. We identified homologs of the spermidine-modified translation factor eIF5a encoded by giant viruses of the Imitervirales. Although AdoMetDC/speD is prevalent among marine phages, some homologs have lost AdoMetDC activity and have evolved into pyruvoyl-dependent ADC or ODC. The pelagiphages that encode the pyruvoyl-dependent ADCs infect the abundant ocean bacterium Candidatus Pelagibacter ubique, which we have found encodes a PLP-dependent ODC homolog that has evolved into an ADC, indicating that infected cells would contain both PLP- and pyruvoyl-dependent ADCs. Complete or partial spermidine or homospermidine biosynthetic pathways are found encoded in the giant viruses of the Algavirales and Imitervirales, and in addition, some viruses of the Imitervirales can release spermidine from the inactive N-acetylspermidine. In contrast, diverse phages encode spermidine N-acetyltransferase that can sequester spermidine into its inactive N-acetyl form. Together, the virome-encoded enzymes and pathways for biosynthesis and release or biochemical sequestration of spermidine or its structural analog homospermidine consolidate and expand evidence supporting an important and global role of spermidine in virus biology.

The polyamine spermidine (Fig. 1) is a metabolically primordial polycation found throughout bacteria, archaea, and eukaryotes (1). It is a fundamental molecule of life that was likely present in the last universal common ancestor (2). In Escherichia coli, 90% of spermidine is noncovalently bound to RNA (3) and is required for efficient translational elongation by the ribosome (4). Spermidine increases global messenger RNA (mRNA) translation in E. coli by facilitating the queuosine modification of specific tRNA anticodon wobble bases (4). Consistent with these findings, in strains of E. coli deleted for genes that modify the anticodon wobble position in transfer RNAs (tRNAs), spermidine becomes absolutely essential for growth (5), which may be due to spermidine-mediated stabilization of the tRNA interaction with the translating ribosome. Spermidine is not only important for growth of bacteria; over 40 y ago, it was shown that T4 and T7 bacteriophages replicated more slowly in a spermidine-deficient mutant of E. coli (6). Replication of JG004 and N4-like phages in Pseudomonas aeruginosa PAO1 is absolutely dependent on spermidine (7, 8).Open in a separate windowFig. 1.Polyamine metabolic pathways. Pathways biochemically characterized herein are indicated by blue arrows and blue enzyme names.In eukaryotic cells, spermidine is universally required for growth and cell proliferation. An aminobutyl moiety of spermidine (Fig. 1) is transferred by deoxyhypusine synthase (DHS) to a single lysine of the translation factor eIF5A to eventually form the essential hypusine posttranslational modification (9). Hypusinated eIF5a is needed for translation of mRNAs encoding proline-rich motifs and for translation termination (10). Replication of eukaryotic RNA viruses is highly dependent on host spermidine (11), and spermidine-derived hypusination of host eIF5a is required for Ebola virus replication and is considered a potential target to inhibit viral replication (12).Viruses reprogram the metabolism of host cells to make more virions by redirecting expression and activity of host-encoded enzymes and by expressing virus-encoded enzymes. Using homology-based approaches, nucleocytoplasmic large DNA viruses have been found to encode homologs of enzymes involved in nitrogen metabolism, glycolysis, and the tricarboxylic acid cycle (13). Bacteriophages have been found to encode homologs of enzymes involved in inorganic sulfur metabolism (14) and nucleotide metabolism (15). The eukaryotic chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) encodes an entire functional biosynthetic pathway for production of homospermidine (Fig. 1), a structural analog of spermidine, consisting of L-arginine decarboxylase (ADC), agmatine deiminase/iminohydrolase (AIH), N-carbamoylputrescine amidohydrolase (NCPAH), and homospermidine synthase (HSS) (16–18). In addition, PBCV-1 encodes a polyamine N-acetyltransferase (19). A biochemically functional HSS enzyme is encoded by Ralstonia phage ϕRSL1 (20). Considering the importance of polyamines to phage and virus replication, we sought to systematically identify and functionally characterize polyamine metabolic enzymes and pathways encoded in phage and virus genomes. Some of the taxonomic affiliations of giant viruses included in our study are based on a recently published hierarchical taxonomy for the Nucleocytoviricota (21).     

Respiratory syncytial virus disease burden in adults aged 60 years and older in high‐income countries: A systematic literature review and meta‐analysis

BackgroundRespiratory syncytial virus (RSV)‐associated acute respiratory infection (ARI) is an underrecognized cause of illness in older adults. We conducted a systematic literature review and meta‐analysis to estimate the RSV disease burden in adults ≥60 years in high‐income countries.MethodsData on RSV‐ARI and hospitalization attack rates and in‐hospital case fatality rates (hCFR) in adults ≥60 years from the United States, Canada, European countries, Japan, and South Korea were collected based on a systematic literature search (January 1, 2000–November 3, 2021) or via other methods (citation search, unpublished studies cited by a previous meta‐analysis, gray literature, and an RSV‐specific abstract booklet). A random effects meta‐analysis was performed on estimates from the included studies.ResultsTwenty‐one studies were included in the meta‐analysis. The pooled estimates were 1.62% (95% confidence interval [CI]: 0.84–3.08) for RSV‐ARI attack rate, 0.15% (95% CI: 0.09–0.22) for hospitalization attack rate, and 7.13% (95% CI: 5.40–9.36) for hCFR. In 2019, this would translate into approximately 5.2 million cases, 470,000 hospitalizations, and 33,000 in‐hospital deaths in ≥60‐year‐old adults in high‐income countries.ConclusionsRSV disease burden in adults aged ≥60 years in high‐income countries is higher than previously estimated, highlighting the need for RSV prophylaxis in this age group.     

A Nonlinear Relationship Between ALT Levels at Delivery and the Risk of Postpartum ALT Flares in Pregnant Women with Chronic Hepatitis B

Background: The aim of the present study was to investigate the association between alanine aminotransferase (ALT) levels at delivery and postpartum ALT flares among women with chronic hepatitis B (CHB).Methods: Pregnant women with CHB from November 2008 to November 2017 were included in this retrospective study. Multivariable logistic regression analysis and a generalized additive model were performed to determine both linear and nonlinear relationships between ALT levels at delivery and postpartum ALT flares. Stratification analysis was performed to test for effect modifications in subgroups.Results: A total of 2643 women were enrolled. Multivariable analysis indicated that ALT levels at delivery were positively associated with postpartum ALT flares (odds ratio (OR) 1.02, 95% confidence interval (CI) 1.01-1.02, P < 0.0001). When ALT levels were converted to a categorical variable, the ORs and 95% CIs in quartiles 3 and 4 versus quartile 1 were 2.26 (1.43-3.58) and 5.34 (3.48-8.22), respectively (P for trend < 0.001). When ALT levels were dichotomized into a categorical variable according to clinical cutoffs (40 U/L or 19 U/L), the ORs and 95% CIs were 3.06 (2.05-4.57) and 3.31 (2.53-4.35), respectively (P < 0.0001). The ALT level at delivery was also found to have a nonlinear relationship with postpartum ALT flares. The relationship followed an inverted U-shaped curve.Conclusions: The ALT level at delivery was positively correlated with postpartum ALT flares in women with CHB when the ALT level was less than 182.8 U/L. The ALT cutoff (19 U/L) at delivery was more sensitive to predict the risk of ALT flares postpartum.     

原发性肝细胞癌病人PBMCs中HBV X、P基因的整合

目的 探讨外周血单个核细胞（PBMCs）中乙型肝炎病毒（HBV）X、P基因整合与原发性肝细胞癌（HCC）的关系。方法 分离HBsAg阳性的40例原发性肝癌病人PBMCs,提取基因组DNA;分别设计HBVX基因、P基因PCR引物．检测HCC病人PBMCs基因组中HBV的X基因和P基因的整合情况。结果 HCC病人X基因在PBMCs中的整合率为77．5％（31/40）．P基因整合率为15．0％（6／40）,二者差异有显著性（x^2=31．43,P〈0．001）。结论 PBMCs中存在HBVX、P基因的整合．X基因片段的整合及表达是HCC发生的主要因素。     

荔枝核总皂苷体外抗乙型肝炎病毒的作用

0 引言 我国属乙型病毒性肝炎高流行区,2004年中国疾病预防控制中心调查显示我国HBsAg感染率高达9．09％．目前,尚没有理想的治疗慢性乙型肝炎的药物．我国有数千年应用中草药治疗疾病的传统和经验,从中已发现了不少抗乙型肝炎病毒（HBV）的药物．荔枝核是无患子科植物荔枝（Litchi chinensis Sonn）的成熟种子,又名荔仁或荔核,味甘、微苦,归肝、肾经,具有行气散结、祛寒止痛的功效．其化学成分包括皂苷、蒜质和脂肪酸等多种物质．研究发现,荔枝核黄酮类提取物对乙肝病毒HBsAg,HBeAg以及HBVDNA有明显的抑制作用．但荔枝核皂苷是否具有抑制HBV的作用,目前尚未见文献报道．我们采用HepG2．2．15细胞为靶细胞,观察不同浓度荔枝核总皂苷体外对HBV的抑制作用．     

用不同厂家ELISA试剂检测抗HCV结果的差异性分析

目的探讨不同厂家酶联免疫吸附试验（ELISA）试剂检测丙型肝炎病毒抗体（抗HCV）结果的差异性。方法用4种不同厂家生产的第3代ELISA抗HCV试剂检测经上海科华公司生产的ELISA抗HCV试剂检测为阳性的出入境体检人员的血清标本62例,结果不一致的标本再用MP HCV BLOT3.0检测确认。结果A、B、C、D 4种试剂阳性反应数分别为59、50、43和53份,其中试剂B和C、B和D比较差异无统计学意义（P〉0.05）;试剂C和D比较差异有统计学意义（P〈0.05）。4种试剂反应都阳性标本37份,结果不一致的标本25份,经确认有9份标本阳性。结论不同厂家抗HCV试剂检测结果的阳性率有较大差异,提示选择灵敏度较高的试剂进行初筛,并且要有另一种灵敏度和特异性高的试剂作为复检方法,当2种试剂检测都为阳性,且标本吸光度值与阳性判定值（cut off）的比值（S/CO）≥3.8时,则可判定为抗HCV阳性;当检测结果为阳性但其S/CO值≤3.8或其中1种检测方法结果为阴性,建议用免疫重组印迹（RIBA）试验确认。