The endless tale of non-homologous end-joining

DNA double-strand breaks （DSBs） are introduced in cells by ionizing radiation and reactive oxygen species. In addition, they are commonly generated during V（D）J recombination, an essential aspect of the developing immune system. Failure to effectively repair these DSBs can result in chromosome breakage, cell death, onset of cancer, and defects in the immune system of higher vertebrates. Fortunately, all mammalian cells possess two enzymatic pathways that mediate the repair of DSBs： homologous recombination and non-homologous end-joining （NHEJ）. The NHEJ process utilizes enzymes that capture both ends of the broken DNA molecule, bring them together in a synaptic DNA-protein complex, and finally repair the DNA break. In this review, all the known enzymes that play a role in the NHEJ process are discussed and a working model for the co-operation of these enzymes during DSB repair is presented.

Preferential Bivalent Formation in Tetraploid Male of Pacific Oyster Crassostrea gigas Thunberg

Artificially induced tetraploid Pacific oyster, Crassostrea gigas Thunberg, produces more aneuploid gametes than nor- mal diploid one, although they showed a comparable fecundity to diploidy. The meiotic chromosome configuration of 3 tetraploid and 1 tetraploid/triploid mosaic males were analyzed through direct chromosome observation. A majority of metaphase I spermato- cytes contained both bivalents and quadrivalents. The chromosome configuration of these males was characterized by preferential formation of bivalents to quadrivalents. Bivalents appeared in all spermatocytes and consisted of 86% of all chromosome aggregates. In comparison, quadrivalents occurred in 91% spermatocytes and consisted of only 12.6% of all chromosome aggregates. The mean bivalent frequency per spermatocyte varied between 14.4 and 17.2; while that of quadrivalents varied between 2.2 and 2.7. Most quadrivalents were tandemly chained （58%） or circled （39%）. The total number of chromosome aggregates per spermatocyte ranged from 13 to 20 with an average of 17.6; while 18 （16 bivalents and 2 quadrivalents） was the most frequent. Univalents and trivalents appeared in very low frequency. Aneuploid （hypotetraploid） spermatocytes were observed in a low frequency. The chromosome con- figuration of in the mosaic individual was similar to that of tetraploid individuals. The percentage of triploid spermatocytes （2%） of the mosaic individual was significantly lower （2＂2 =30, P〈 0.01） than that of triploid cells （46%） in its somatic tissue.

Preparation and analysis of spermatocyte meiotic pachytene bivalents of pigs for gene mapping

Well-spread meiotic pachytene bivalents were obtained by using the prolonged hypotonic treatment com-bined with high chloroform Carnory’s fixative solution from cells of the testes of domestic pigs. Comparison in the division index and length of pachytene bivalents with metaphase chromosomes showed that those of the former are 5 times higher and 3.42(1.87-5.98) times longer than those of the latter. Comparative studies on chromomere maps of bivalents and mitotic chromosomal G-bands were conducted by using the chromo-some 12 as a example. Sex vesicle and various shapes of synaptic sex chromosomes have been observed.Two-color PRimed IN Situ (PRINS) labeling has been conducted successfully on pachytene bivalents of pigs.

ROLE OF BIVALENT CATIONS AND CHOLINE IN ATP-INDUCED APOPTOSIS OF HUMAN LYMPHOCYTES WITH P2Z RECEPTORS

The role of bivalent cations and choline in ATP induced apoptosis via P2Z purinoceptor was investigated in human leukemic lymphocytes. In vitro exposure of leukemic lymphocytes with P2Z receptors to 1 mmol/L ATP or 0 1 mmol/L benzoylbenzoic ATP(BzATP) for 8 h in the presence of choline, 1 mmol/L Mg 2+ or other bivalent cations, and ATP induced DNA breaks, associated with apoptosis were quantified by TdT assay. We observed that (1) Extracellular Mg 2+ or Ca 2+ stimulated ATP induced DNA fragmentation in a dose dependent manner, and the compatible evidence was provided by the inhibition of ATP induced DNA fragmentation in the present of EGTA or EDTA; (2) ATP induced DNA fragmentation was completely inhibited by 1 mmol/L Zn 2+ ;(3)ATP induced DNA breaks were not affected by Ba 2+ , Sr 2+ , Co 2+ when they were substituted for extracellular Mg 2+ or Ca 2+ ;(4)Choline, an inhibitor of phospholipase D(PLD) stimulated by ATP through P2Z receptor in human lymphocytes, was also a partial inhibitor of ATP induced DNA fragmentation, and the results were confirmed by flow cytometric analysis (FCA); (5)ATP induced DNA fragmentation was completely obliterated when the temperature was lower than 10℃. These results suggest that the endonuclease and PLD may be involved in ATP induced apoptosis in human lymphocytes via P2Z receptor.

Immuno-Protective Efficiency of the Bivalent Inactivated Vaccine Against Vibrio scophthalmi and Aeromonas salmonicida Infections in Turbot(Scophthalmus maximus L.)

Vibrio scophthalmi and Aeromonas salmonicida can cause high turbot mortality and huge economic losses.Presently,vaccination is the most promising method for preventing communicable diseases.In this study,we used formalin to kill V.scophthalmi and A.salmonicida cells,and mixed with the mineralized oil adjuvant(Montanide^(TM)ISA 763 AVG)to prepare the bivalent inactivated vaccine.The results showed that turbot inoculated with the bivalent inactivated vaccine exhibited strong tolerance to the infection of V.scophthalmi and A.salmonicida,and no obvious clinical symptoms and pathological changes were observed.The activities of enzymes lysozyme,acid phosphatase and complement C3 had significantly increased after the vaccination.The antibody titer response of vaccinated turbot was greatly boosted,which was positively connected with the immunological impact according to ELISA results.Simultaneously,the expression levels of immune-related genes such as MHC-IIα,MHC-IIβ,CD4,CD8,TNF-αand IL^(-1)βwere up-regulated,demonstrating that it might stimulate humoral and cellular immunological response in turbot.These findings highlight the potential of the bivalent inactivated vaccine for controlling V.scophthalmi and A.salmonicida infections in turbot.

Effectiveness of Hemorrhagic Fever with Renal Syndrome Bivalent Vaccine in China:A Metaanalysis

Objective To evaluate the effectiveness of Hemorrhagic Fever with Renal Syndrome(HFRS) bivalent vaccine in field.Methods The articles on effectiveness of HFRS bivalent vaccine were retrieved from Vip Database,China Journal Full-text Database,Wanfang database,China Hospital Knowledge Database,Chinese Biomedical Literature Database,MEDLINE and ProQuest.Two persons extracted data and evaluated the quality of data together for meta-analysis.Results Seven articles were included into the analysis,and two articles were random clinical trials,five were quasi-trials.Meta-analysis showed that the overall effectiveness of HFRS bivalent vaccine was 85%(95%confidence interval:53%-95%) within one year after vaccination,and the effectiveness in two-dose recipients and three-dose recipients was 87%(95%confidence interval:54%-96%) and 60%,respectively;it was 96%(95%confidence interval:78%-99%) within 2-5 years after vaccination,and the effectiveness in two-dose recipients and three-dose recipients was 95%(95%confidence interval:19%-100%) and 96%(95%confidence interval:70%-99%),respectively;it was 100%(only one article included) within 6-9.6 years after vaccination.The effectiveness in two-dose recipients was 88%(95%confidence interval:62%-96%) during 1-2.5 years after vaccination,and that in three-dose recipients was 94%(95%confidence interval:70%-99%) during 1-5 years after vaccination.Conclusions HFRS bivalent vaccine is effective in field,and there is no difference between two-dose recipients and three-dose recipients.We should do some further studies on the long-term effectiveness of HFRS bivalent vaccine and on the age of vaccine reception.

Study of the Temperature-Programmed Desorption of Carbon Dioxide (CO2) on Zeolites X Modified with Bivalent Cations

Study of physisorbed and chemisorbed carbon dioxide (CO2) species was carried out on the NaX zeolite modified by cationic exchanges with bivalent cations (Ca2+ and Ba2+) by temperature-programmed desorption of CO2 (CO2-TPD). Others results were obtained by infrared to complete the study. The results of this research showed, in the physisorption region (213 - 473 K), that the cationic exchanges on NaX zeolite with bivalent cations increase slightly the interactions of CO2 molecule with adsorbents and/or cationic site. Indeed, the desorption energies of physisorbed CO2 obtained on the reference zeolite NaX (13.5 kJ·mol-1) are lower than that of exchanged zeolites E-CaX and E-BaX (15.77 and 15.17 kJ·mol-1 respectively). In the chemisorbed CO2 region (573 - 873 K), the desorption energies related to desorbed species (bidentate carbonates: CO32-) on the exchanged zeolites E-CaX and E-BaX are about 81 kJ·mol-1, higher than the desorbed species (bicarbonates: HCO32-) on the reference R-NaX (62 kJ·mol-1). In addition, the exchanged E-BaX zeolite develops the secondary adsorption sites corresponding to bicarbonates species with desorption energies of 35 kJ·mol-1 lower to desorption energies of bicarbonates noted on the reference zeolite NaX.

RADIOIODINATION AND PHARMACOKINETICS OF BIVALENT ANALOG OF PRACTOLOL AS MYOCARDIAL IMAGING AGENT

Solid phase exchange radioiodination method was used to label the compound.Pharmacokinetics was studied in rats and the data were dealt with by computer. The results indicate that the compound would be a potential myocardial imaging agent.

Molecular dynamics simulations of A-DNA in bivalent metal ions salt solution

A-form DNA is one of the biologically active double helical structure.The study of A-DNA structure has an extensive application for developing the field of DNA packaging in biotechnology.In aqueous solution,the A-DNA structure will have a free transformation,the A-DNA structure will be translated into B-form structure with the evolution of time,and eventually stabilized in the B-DNA structure.To explore the stability function of the bivalent metal ions on the A-DNA structure,a series of molecular dynamics simulations have been performed on the A-DNA of sequence(CCCGGCCGGG).The results show that bivalent metal ions(Mg^(2+),Zn^(2+),Ca^(2+))generate a great effect on the structural stability of A-DNA in the environment of high concentration.As the interaction between metal ions and electronegative DNA chains,the stability of A-DNA in solution is gradually improved with the increasing solution concentration of ions.In metal salt solution with high concentration,metal ions can be easily distributed in the solvation shells around the phosphate groups and further lead to the formation of shorter and more compact DNA structure.Also,under the condition of the same concentration and valency of the metal ions,the stability of A-DNA structure is different.The calculations indicate that the structure of A-DNA in CaCl_(2)solution is less stable than in MgCl_(2)and ZnCl_(2)solution.

Histone methylation in Huntington's disease:are bivalent promoters the critical targets?

Huntington’s disease（HD）is a currently incurable,late onset,progressive,ultimately fatal neurological disorder（Bates et al.,2015）.We have recently published the results of comprehensive genetic interaction tests aimed at identification of histone methyltransferases and demethylases involved in HD pathogenesis in a Drosophila model of the disease（Song et al.,2018）.

THE STRUCTURE OF ACTIVE SITE AND THE ROLE OF BIVALENT CATION IN FERRITE-FERRIC OXIDE CATALYSTS FOR OXIDATIVE DEHYDROGENATION OF BUTENES

The relations between catalytic activities and compositions of the systems Mg_xZn_(1-x)Fe_2O_4, Co_xZn_(1-x)Fe_2O_4, Co_xMg_(1-x)Fe_2O_4, Cd_xZn_(1-x)Fe_2O_4 and Mg_xZn_(1-x)Fe_2O_4·0.17Fe_2O_3 have been studied by flow differential reactor, XRD, and derivative IR techniques. It has been found that the appropriate normal-inverse spinel combination substantially increases the activity for the title raction. The structure of the active site and the role of the bivalent cation in the title catalyst have been inferred.

Observation on the Efficiency of the Mongolian Gerbil Kidney Tissue Culture Inactivated Bivalent Vaccine for Hemorrhagic Fever with Renal Syndrome

The Z 10 and Z 37 strains of hemorrhagic fever with renal syndrome (HFRS) virus and the Mongolian gerbil ( Merions unguiculatus ) kidney cells were used to prepare the inactivated bivalent vaccine. A phase Ⅱ clinical trial use of this vaccine was made in 750 Chinese volunteers. The results showed that the side reaction rate was 2.5% and the sero-conversion rate of neutralizing antibodies against Hantaan and Seoul viruses in the inoculated volunteers were 87.6% and 96.3% respectively.

水液相下二价镁缬氨酸配合物(Val·Mg^(2+))对映异构的密度泛函理论

采用密度泛函理论中处理远程弱作用的M06-2X和MN15杂化交换泛函方法以及SMD模型方法(处理溶剂效应),对生理环境下二价镁缬氨酸(Val·Mg^(2+))的对映异构(S手性→R手性)转变过程的机制进行研究.对映异构反应通道研究结果表明:手性Val·Mg^(2+)对映异构反应通道分别是H质子以羰基O为桥、羰基O与氨基N联合为桥以及氨基N独自为桥迁移.反应过程的自由能势能面计算表明:H质子以N独自为桥的迁移反应具有优势;在水溶剂的极性作用下,优势反应通道速度控制步骤的能垒为210.4 kJ/mol,水分子(簇)的催化使该能垒降至116.1~118.3 kJ/mol.水液相下二价镁缬氨酸配合物对映异构的速度极缓慢,其可安全用于生命体,二价镁离子和缬氨酸同补.

表达鸡传染性喉气管炎病毒gD蛋白的重组嵌合型新城疫病毒La Sota株的构建

为构建表达鸡传染性喉气管炎病毒(ILTV)糖蛋白D(gD)的重组新城疫病毒(NDV)La Sota株,本研究将ILTV强毒株gD基因胞外域与NDV F基因信号肽、跨膜域和胞质尾区融合,并插入到含有NDV基因VII型F和HN基因的嵌合型La Sota株感染性cDNA克隆pLa Sota-VIIF/HN的P和M基因之间,将获得的重组感染性克隆pLa Sota-VIIF/HN-gD与辅助质粒pCIneo-NP-P-L共转染BHK-21细胞,拯救出表达gD蛋白的重组嵌合型NDV La Sota株rLaSota-VIIF/HN-gD,并采用血凝试验鉴定正确后,将重组病毒在9日龄SPF鸡胚中连续传至10代,提取10代重组病毒基因组RNA,反转录成c DNA作为模板,以ILTV gD基因插入位点两侧的鉴定引物进行PCR鉴定;采用第10代重组病毒感染BHK-21细胞,以ILTV gD蛋白多克隆抗体作为一抗进行间接免疫荧光试验(IFA);分别对鸡红细胞吸附的重组病毒感染的鸡胚尿囊液上清和从红细胞上解离下来的纯化的重组NDV病毒粒子经western blot鉴定,并对重组病毒对鸡胚的致病性和在鸡胚中的复制动态进行初步研究。PCR结果显示ILTV gD基因能够在重组病毒中稳定存在;IFA和western blot鉴定结果显示,重组病毒能够正确表达ILTV的gD蛋白,而且gD蛋白嵌合表达在重组病毒颗粒上。鸡胚致病性试验和鸡胚中的复制动态试验结果显示,重组病毒保持了La Sota疫苗株的低致病性和良好的复制特性,rLaSota-VIIF/HN-gD的鸡胚平均死亡时间(MDT)为168 h,1日龄雏鸡脑内接种该重组病毒的致病指数(ICPI)为0.20,鸡胚半数感染量(EID_(50))峰值可达10^(-8.66)/100μL。本研究所制备的重组病毒r LaSota-VIIF/HN-gD为研制基因VII型NDV和ILTV的二联活疫苗奠定了基础。

溶解性二价铁-铁氧化物非均相体系氧化还原电位的电化学测定方法探究

溶解性二价铁(Fe_(aq)^(2+)-)-铁氧化物非均相体系的氧化还原能力显著影响含水层中有毒重金属和有机污染物的迁移转化行为。然而,非均相体系氧化还原电位(Eh)的测定存在平衡缓慢和结果不稳定等难题,故亟待开发与优化电化学法快速准确测定Eh,实现Fe_(aq)^(2+)-铁氧化物非均相体系氧化还原能力的定量表征。本文选取针铁矿作为常见的铁氧化物,探讨了介导和非介导电位法测定Fe_(aq)^(2+)-针铁矿非均相体系Eh的优化实验条件,研究了介导物质的类型与添加顺序以及工作电极预处理方法等条件对Eh测定的影响,并通过能斯特方程验证电位法的可行性。结果表明:工作电极的表面状态、介导物质的选择以及针铁矿-工作电极之间平衡的建立对Eh测定十分关键。介导法能有效地缩短测定时间,但需要选择合适的介导物质;非介导法需确保工作电极与针铁矿之间平衡的建立。同时,利用非介导法测定了不同pH和Fe_(aq)^(2+)-浓度下不同粒径针铁矿与Fe_(aq)^(2+)-非均相体系的Eh,根据能斯特方程和最小二乘法多元线性拟合得到不同粒径针铁矿的标准氧化还原电位(Eh0),对于粒径为200、700和1000nm的针铁矿Eh0分别为815、802和782mV,验证了优化后电位法的可行性。本文的结论可为矿物非均相体系Eh的测定提供方法学参考,也为预测Fe_(aq)^(2+)-铁氧化物非均相体系参与的污染物衰减速率提供理论支撑。

猪流感二价灭活疫苗对H1N1亚型流行毒株的攻毒保护效果

旨在评价猪流感二价灭活疫苗(H1N1 LN株+H3N2 HLJ株)对2021年国内H1N1亚型猪流感流行毒株的交叉保护效果。将10头4周龄健康易感猪随机均分为疫苗接种组和对照组,疫苗接种组每头接种疫苗2 mL,首免14 d后进行二免,对照组未接种疫苗;首免后28 d,每头猪经气管内注射A/Swine/Jiangsu/NL33/2021(H1N1)(简称NL33株)4.0 mL;综合临床症状、鼻拭子病毒分离和肺脏病变3个方面进行判定。结果:试验组保护率为80%,对照组发病率为100%。综上,猪流感二价灭活疫苗(H1N1 LN株+H3N2 HLJ株)接种对2021年国内流行的H1N1亚型猪流感病毒攻击产生了较好的交叉保护效果,猪群接种该疫苗后能有效抵抗猪流感流行毒株的攻击。

Construction of a bivalent vaccine candidate against HAdV4/HAdV7 based on capsid-display strategy via Red-homologous recombination and counter-selection methodology

Human adenoviruses(HAdvs)are major respiratory pathogens.Specifically,human adenovirus type 4(HAdV4)and human adenovirus type 7(HAdV7)are known for causing fever and pneumonia,with docu-mented cases of fatalities among the population.In recent years,HAdV4/HAdv7 has been implicated in caus-ing substantial outbreaks,leading to increased morbidity in multiple countries.Most HAdV4 and HAdV7 infections have been reported in North America,Asia,Europe,Africa,South America,Oceania,and the Middle East.Most fatalities occurred in North America(the United States)and Asia(China and Singapore).Engineered recombinant adenoviruses have played a crucial role as vaccine vectors.In this study,we con-structed a recombinant adenovirus,Ad4ITRmut-Ad7E3,and evaluated it in vitro and in vivo.We observed that the replication rate of Ad4ITRmut-Ad7E3 was lower than that of the RI-67 strain,indicating that the mutation of inverted terminal repeats(ITRs)weakened the replication ability of HAdV4.Immunization of BALB/c mice with the bivalent Ad4ITRmut-Ad7E3 vaccine strain,administered by intraperitoneal injection and oral gavage,resulted in the elicitation of neutralizing antibodies targeting HAdV4 and HAdv7.This finding not only pro-vides a novel method and technique for the efficient construction of a polyvalent recombinant adenovirus vac-cine candidate against HAdV4 and HAdv7 but also against other prevalent adenovirus serotypes such as HAdV3,HAdV11,HAdV14,and HAdv55,from various regions.

国产双价人乳头瘤病毒疫苗和进口双价人乳头瘤病毒疫苗有效性的对比性研究

目的:比较国产双价人乳头瘤病毒(Human Papilloma virus,HPV)疫苗及进口双价人乳头瘤病毒(以下简称HPV)疫苗预防HPV16/HPV18感染的有效性。方法:本研究选取江西省妇幼保健院2020年8月-2020年10月自愿接受宫颈癌筛查的200名女性为研究对象,根据其接种HPV疫苗的意愿,分为国产双价HPV疫苗组(100名)与进口双价HPV疫苗组(100名)。研究以同期在我院门诊接受宫颈癌筛查的100名女性为对照组。研究入组时各组的宫颈细胞检查及HPV检测结果均无异常,待国产双价HPV疫苗组和进口双价HPV疫苗组完成3针HPV疫苗接种后24 m,比较三组的HPV16/HPV18阳性率。结果:三组的HPV16/HPV18阳性率比较,差异有统计学意义(P<0.05)。国产双价组与进口双价组两组的*HPV16/HPV18阳性率比较,差异无统计学意义(P>0.05)。对照组HPV16/HPV18阳性率高于国产双价组,对照组HPV16/HPV18阳性率高于进口双价组,以上两组间差异有统计学意义(P<0.05)。结论:国产双价HPV疫苗和进口双价HPV疫苗预防HPV16/HPV18相关感染具有相近的保护效力。

Safety,immunogenicity,and preliminary efficacy of a randomized clinical trial ofomicron XBB.1.5-containing bivalent mRNA vaccine

Periodically updating coronavirus disease 19(COVID-19)vaccines that offer broad-spectrum protection is needed giventhe strong immune evasion by the circulating omicron sublineages.The effectiveness of prototype and BA.4/5-containing bivalent mRNA vaccines is reduced when XBB subvariants predominate.We initiated an observer-blinded,threearms study in 376 patients in Chinese individuals aged from 18 to 55 years old who had previously received three dosesCOVID-19 vaccine.Immunogenicity in terms of neutralizing antibodies elicited by a 30-mg dose of XBB.1.5-containingbivalent vaccine(RQ3027),a 30-mg dose of BA.2/BA.5-Alpha/Beta bivalent vaccine(RQ3025)and their precedent 30-mg Alpha/Beta(combined mutations)monovalent mRNA vaccine(RQ3013)and safety are primary and secondary endpoints,respectively.We recorded prescribed COVID-19 cases to explore the preliminary efficacy of three vaccines.RQ3027 and RQ3025 boosters elicited superior neutralizing antibodies(NAbs)against XBB.1.5,XBB.1.16,XBB.1.9.1,and JN.1 compared to RQ3013 at day 14 in participants without SARS-CoV-2 infection.All study vaccines were welltolerated without serious adverse reactions identified.The incidence rates per 1000 person-years of COVID-19 casesduring the 2nd-19th week after randomization were lowest in RQ3027.Overall,our data show that XBB.1.5-containingbivalent booster generated superior immunogenicity and better protection against newer severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants compared to BA.2/BA.5-containing bivalent and Alpha/Beta monovalentwith no new safety concerns.

双价人乳头瘤病毒疫苗(毕赤酵母)细菌内毒素检查方法的建立

目的建立双价人乳头瘤病毒疫苗(毕赤酵母)的细菌内毒素检查方法。方法按《中国药典》2020年版三部通则1143细菌内毒素检查法及四部指导原则9251“细菌内毒素检查法应用指导原则”中的相关规定进行凝胶法、光度法(动态浊度法和动态显色法)测定细菌内毒素方法学研究。结果双价人乳头瘤病毒疫苗(毕赤酵母)经40倍及以上稀释,对凝胶法反应无干扰,同时动态浊度法及动态显色法回收率也可达到要求。结论建立双价人乳头瘤病毒疫苗(毕赤酵母)的凝胶法、动态浊度法及动态显色法进行细菌内毒素检查可行。