Expression of the tobacco β-1,3-glucanase gene, PR-2d, following induction of SAR with Peronospora tabacina

Systemic acquired resistance (SAR) is induced following inoculation of Peronospora tabacina sporangia into the stems of Nicotiana tabacum plants highly susceptible to the pathogen. Previous results have shown that accumulation of acidic β-1,3-glucanases (PR-2's) following induction of SAR by P. tabacina may contribute to resistance to P. tabacina. We showed that up-regulation of the PR-2 gene, PR-2d, following stem inoculation with P. tabacina, is associated with SAR. Studies using plants transformed with GUS constructs containing the full length promoter from PR-2d or promoter deletions, provided evidence that a previously characterized regulatory element that is involved in response to salicylic acid (SA), may be involved in regulation of PR-2d following induction of SAR with P. tabacina. This work provides evidence that regulation of PR-2 genes during P. tabacina-induced SAR may be similar to regulation of these genes during infection of N-gene tobacco by TMV or following exogenous application of SA, and provides further support for the role of SA in regulation of genes during P. tabacina-induced SAR.     

鸡IL-18真核表达载体的构建及其对新城疫疫苗免疫增强作用的研究

利用首次从鸡新城疫疫苗接种的鸡胚脾细胞中扩增出的鸡IL 18 全基因,构建IL 18 真核表达载体(pcDNA3 IL18),并观察其对新城疫疫苗的免疫增强作用。结果表明,同时接种pcDNA3 IL18 质粒和活疫苗的免疫鸡在接种后35 d内,特别是15 d之后所产生的HI抗体效价和T、B淋巴细胞增殖反应均高于单纯疫苗免疫组及pcDNA3 空白质粒和疫苗联合免疫组。其中,HI抗体效价在15 d 时差异显著(P<0 05),在30 和35 d时差异极显著(P<0 01); T淋巴细胞增殖反应在15 d后均表现为差异显著(P<0 05〉或极显著(P<0 01);而单纯疫苗组与空白质粒和疫苗联合免疫组之间的各测定指标则无明显的差异(P>0 05)。在35 d时进行攻毒, pcDNA3 IL18和疫苗联合免疫组的保护率为83.3%,而单纯疫苗免疫组、空白质粒和疫苗联合免疫组鸡的保护率则分别只有61.5%和66.7%。说明该pcDNA3 IL18真核表达质粒在鸡体内得到了表达,表达产物不仅能够显著增强新城疫疫苗所诱导的细胞免疫和体液免疫反应,而且还可以明显提高疫苗的保护率。     

鸡新城疫强毒株的分离与鉴定

从山东某鸡场的产蛋下降而无其他典型ND症状的高抗体蛋鸡群中分离到一株病毒。经过试验鉴定．该分离株具有血凝性，且可被ND标准阳性血清所抑制和中和，不能被AI（H5亚型与H9亚型）标准阳性血清抑制；该病毒的最小致死量病毒致死鸡胚的平均时间（MDT）为50．4，1日龄SPF鸡脑内接种分离病毒致病指数（ICPI）为1．85，6周龄SPF鸡静脉接种致病指数（WPI）为2．42，回归试验鸡出现了新城疫症状和病变，该病毒株确定为新城疫病毒强毒型，并暂命名为ShD-dzh04。     

2000～2004年间广西新城疫病毒强毒株的分离与鉴定

近年来从广西不同地区规模化鸡场的13个肉鸡群病死鸡中分离到13株有血凝性的病毒,这13株病毒的血凝性均能被新城疫标准阳性血清抑制,经过血凝(HA)试验、血凝抑制(HI)试验和RT-PCR检测结果确定为新城疫病毒.13株病毒的生物学特性测定实验结果证明该13株病毒均为新城疫病毒强毒株.     

禽网状内皮组织增生病病毒和马立克氏病病毒共感染对鸡的致肿瘤作用

用禽网状内皮组织增生病病毒(REV)和马立克氏病病毒(MDV)共感染肉鸡，研究这2种病毒对鸡的致瘤作用，结果表明肉鸡共感染MDV和REV后13d即可发生死亡．接种后100d死亡率达84％。死亡鸡的肝脏、脾脏、肾脏和心脏等可以形成2种外观明显不同的散在的大肿瘤结节和弥漫性的小肿瘤结节。取发病鸡的肝脏、脾脏、肾脏、心脏和腺胃等组织样品做连续石蜡切片，HE染色后发现这些脏器均存在2种不同类型的肿瘤细胞增生。对这些连续切片分别用MDV和REV的单克隆抗体进行间接荧光试验，则同1份样品存在可以与REV和MDV分别呈现阳性反应的肿瘤细胞团，结果表明REV和MDV可以在感染鸡的体内分别诱发形成肿瘤。在接种后14、21、28和42d随机采集3只鸡的全血分离MDV和REV，均可以同时分离到MDV和REV。表明REV和MDV的共感染延长了病毒血症的时间。     

新城疫病毒F基因的真核表达及其免疫原性检测

为了探讨F基因在DNA免疫防制新城疫(ND)中的免疫原性,将NDV Z株F基因插入到真核表达载体pcDNA3.1/V5-H is-TOPO中,构建了真核表达质粒pcDNA NDV ZF。在脂质体作用下将pcDNA NDV ZF转染CEF细胞,用间接免疫荧光试验检测,在CEF细胞中可见有大量F蛋白表达。将重组质粒以100μg/只的剂量肌注免疫SPF雏鸡,经间接ELISA试验检测二免前后的血清,结果证明,pcDNA NDV ZF基因可在SPF鸡体内诱导相应抗体的产生,具有特定的免疫原性。     

Canine GM2‐Gangliosidosis Sandhoff Disease Associated with a 3‐Base Pair Deletion in the HEXB Gene

Background

GM2‐gangliosidosis is a fatal neurodegenerative lysosomal storage disease (LSD) caused by deficiency of either β‐hexosaminidase A (Hex‐A) and β‐hexosaminidase B (Hex‐B) together, or the GM2 activator protein. Clinical signs can be variable and are not pathognomonic for the specific, causal deficiency.

Objectives

To characterize the phenotype and genotype of GM2‐gangliosidosis disease in an affected dog.

Animals

One affected Shiba Inu and a clinically healthy dog.

Methods

Clinical and neurologic evaluation, brain magnetic resonance imaging (MRI), assays of lysosomal enzyme activities, and sequencing of all coding regions of HEXA, HEXB, and GM2A genes.

Results

A 14‐month‐old, female Shiba Inu presented with clinical signs resembling GM2‐gangliosidosis in humans and GM1‐gangliosidosis in the Shiba Inu. Magnetic resonance imaging (MRI) of the dog's brain indicated neurodegenerative disease, and evaluation of cerebrospinal fluid (CSF) identified storage granules in leukocytes. Lysosomal enzyme assays of plasma and leukocytes showed deficiencies of Hex‐A and Hex‐B activities in both tissues. Genetic analysis identified a homozygous, 3‐base pair deletion in the HEXB gene (c.618‐620delCCT).

Conclusions and Clinical Importance

Clinical, biochemical, and molecular features are characterized in a Shiba Inu with GM2‐gangliosidosis. The deletion of 3 adjacent base pairs in HEXB predicts the loss of a leucine residue at amino acid position 207 (p.Leu207del) supporting the hypothesis that GM2‐gangliosidosis seen in this dog is the Sandhoff type. Because GM1‐gangliosidosis also exists in this breed with almost identical clinical signs, genetic testing for both GM1‐ and GM2‐gangliosidosis should be considered to make a definitive diagnosis.