去除Wolbachia 对丽蝇蛹集金小蜂繁殖适合度和成蜂寿命的影响

【目的】明确内共生菌 Wolbachia 对丽蝇蛹集金小蜂 Nasonia vitripennis 繁殖适合度和成蜂寿命的影响。【方法】通过给自然感染 Wolbachia 的丽蝇蛹集金小蜂成蜂喂食不同浓度的利福平来消除其体内的 Wolbachia,然后进行10个世代的连续饲养,探究不同浓度利福平对丽蝇蛹集金小蜂体内 Wolbachia 的去除效果和去除 Wolbachia 后对丽蝇蛹集金小蜂繁殖力、性比（雌蜂占子代数量的比值）和成蜂寿命的影响。【结果】低浓度利福平（0.1~0.5 mg/mL）对丽蝇蛹集金小蜂的毒害作用较小,而高浓度利福平（0.7~10.0 mg/mL）对丽蝇蛹集金小蜂的毒害作用较大,但二者均能去除丽蝇蛹集金小蜂体内的 Wolbachia;去除 Wolbachia 后丽蝇蛹集金小蜂的出蜂量显著下降（P <0.01）,子代中性比显著下降（P <0.01）,但寿命无明显差异。【结论】不同浓度利福平均能去除丽蝇蛹集金小蜂体内Wolbachia,但效果不一致;Wolbachia 对丽蝇蛹集金小蜂的出蜂量和子代性比均有显著影响,对成蜂寿命无显著影响。     

十字花科黑腐病菌中影响致病相关基因XC3814表达的基因鉴定

十字花科黑腐病菌8004菌株的XC3814基因与致病性和胞外多糖合成有关。文章将XC3814的启动子与报告基因sacB融合, 构建了XC3814的表达报告质粒pL3814sac。将该质粒导入野生型菌株8004, 获得了报告菌株8004/pL3814sac。利用转座子EZ::Tn5对报告菌株的基因组进行随机诱变, 分离到3株耐蔗糖的突变体。分析发现其中的1株突变体是由EZ::Tn5插入到编号为XC3882的未知功能的基因所产生的。将由XC3814启动子与报告基因gusA融合得到的报告质粒pGUS3814分别导入8004菌株和XC3882的转座子Tn5gusA5插入突变体, 测定比较pGUS3814的GUS表达水平, 结果显示在XC3882突变体背景下GUS的表达水平比在野生型背景下降低81.3%, 表明XC3814基因的表达水平受XC3882基因的影响。     

应用流式细胞术测定17种中国野生蔷薇核DNA含量

以17种中国野生蔷薇为试材,采用改良的LB 01裂解液,以4种不同的标准植物——大豆（Glycine max Merr.‘Polanka’）、绿豆（Vigna radiata（L.） Wilczek）、番茄（Lycopersicon esculentum Miller）和玉米（Zea mays L.）为外标,以二倍体材料丽江蔷薇（Rosa×lichiangensis Yü et Ku）为内部参照,利用流式细胞术对其核DNA含量及染色体倍性进行检测,并采用常规染色体压片法验证倍性准确性。本研究首次检测了3个二倍体种——商城蔷薇（Rosa shangchengensis T.C.Ku）、广东蔷薇（Rosa kwangtungensis Yü et Tsai）和无刺刺梨（Rosa roxburghii f.inermis S.D.Shi）,1个三倍体种——伞房蔷薇（Rosa corymbulosa Rolfe）和1个四倍体种——弯刺蔷薇（Rosa beggeriana Schrenk）的核DNA含量及基因组大小。结果表明,流式细胞术检测结果与常规染色体压片法结果一致,可对中国野生蔷薇的倍性研究进行补充。本研究结果可丰富中国蔷薇属植物的细胞遗传学背景资料并为繁育新品种提供理论依据。     

彭泽鲫卵源致病性水霉的鉴定及其生物学特性

从患病的彭泽鲫卵上分离3株丝状真菌,经人工感染试验证实其中1株丝状真菌JL1对彭泽鲫卵具有致病性,并进一步研究了其形态与生长特性,开展了ITS rDNA序列分析。实验结果表明,菌株JL1菌丝为透明管状结构,中间无横隔,分枝较少;游动孢子囊多数呈棒状,游动孢子呈多排排列,发育成熟后从孢子囊中释放出来,并迅速游离;藏卵器呈球形,与雄器同枝或异枝。菌株JL1的ITS rDNA序列与GenBank基因库中水霉属菌株自然聚类,同源性高达99%,与Saprolegnia sp.H(登录号:EF460351)的亲缘关系最近。结合形态特征与ITS序列鉴定的结果,判定菌株JL1为水霉菌(Saprolegnia sp.)。此外,菌株JL1在5°C-30°C、pH 4-11范围内均能生长,最适生长温度和pH范围分别为25°C-30°C和6-9。同时菌株JL1对NaCl敏感,质量分数为2%的NaCl即可抑制其生长,可以作为该病防治的依据。     

The Effect of Bovine IFN-α on the Immune Response in Guinea Pigs Vaccinatedwith DNA Vaccine of Foot-and-Mouth Disease Virus

Foot-and-mouth disease virus (FMDV) belongs to thegenus Aphthovirus of the family Picornavidae. The FMDVgenome is a copy of positive-sense, single-stranded RNA,which contains one large open reading frame (ORF). TheORF is translated into a polypeptide, which undergoesautoproteolytic cleavage to produce the structural and non-structural proteins and ultimately forms mature viral pro-teins [1,2]. FMD is caused by the FMDV, which is a highly conta-gious vesicular disease of cloven-hoofe…     

Quantitative Detection of the Foot-And-Mouth Disease Virus Serotype O 146S Antigen for Vaccine Production Using a Double-Antibody Sandwich ELISA and Nonlinear Standard Curves

The efficacy of an inactivated foot-and-mouth disease (FMD) vaccine is mainly dependent on the integrity of the foot-and-mouth disease virus (FMDV) particles. At present, the standard method to quantify the active component, the 146S antigen, of FMD vaccines is sucrose density gradient (SDG) analysis. However, this method is highly operator dependent and difficult to automate. In contrast, the enzyme-linked immunosorbent assay (ELISA) is a time-saving technique that provides greater simplicity and sensitivity. To establish a valid method to detect and quantify the 146S antigen of a serotype O FMD vaccine, a double-antibody sandwich (DAS) ELISA was compared with an SDG analysis. The DAS ELISA was highly correlated with the SDG method (R² = 0.9215, P<0.01). In contrast to the SDG method, the DAS ELISA was rapid, robust, repeatable and highly sensitive, with a minimum quantification limit of 0.06 μg/mL. This method can be used to determine the effective antigen yields in inactivated vaccines and thus represents an alternative for assessing the potency of FMD vaccines in vitro. But it still needs to be prospectively validated by analyzing a new vaccine preparation and determining the proper protective dose followed by an in vivo vaccination-challenge study to confirm the ELISA findings.     

Viroporin Activity of the Foot-and-Mouth Disease Virus Non-Structural 2B Protein

Viroporins are a family of low-molecular-weight hydrophobic transmembrane proteins that are encoded by various animal viruses. Viroporins form transmembrane pores in host cells via oligomerization, thereby destroying cellular homeostasis and inducing cytopathy for virus replication and virion release. Among the Picornaviridae family of viruses, the 2B protein encoded by enteroviruses is well understood, whereas the viroporin activity of the 2B protein encoded by the foot-and-mouth disease virus (FMDV) has not yet been described. An analysis of the FMDV 2B protein domains by computer-aided programs conducted in this study revealed that this protein may contain two transmembrane regions. Further biochemical, biophysical and functional studies revealed that the protein possesses a number of features typical of a viroporin when it is overexpressed in bacterial and mammalian cells as well as in FMDV-infected cells. The protein was found to be mainly localized in the endoplasmic reticulum (ER), with both the N- and C-terminal domains stretched into the cytosol. It exhibited cytotoxicity in Escherichia coli, which attenuated 2B protein expression. The release of virions from cells infected with FMDV was inhibited by amantadine, a viroporin inhibitor. The 2B protein monomers interacted with each other to form both intracellular and extracellular oligomers. The Ca²⁺ concentration in the cells increased, and the integrity of the cytoplasmic membrane was disrupted in cells that expressed the 2B protein. Moreover, the 2B protein induced intense autophagy in host cells. All of the results of this study demonstrate that the FMDV 2B protein has properties that are also found in other viroporins and may be involved in the infection mechanism of FMDV.