雏番鸭病毒性肝炎病毒的分离与鉴定

从洛江区临床发病鸭分离到2株病毒,2株分离病毒能够致死鸡胚,能被Ⅰ型鸭病毒性肝炎标准强毒高免血清特异性中和。分离毒株在鸡胚上传代培养,并测定ELD50分别为10-6.32/0.2 m L、10-5.49/0.2 m L;经动物回归试验,对1日龄雏番鸭的致死率分别为80%和70%,雏番鸭出现明显的角弓反张姿态,剖检可见肝脏出血斑、出血点,为鸭病毒性肝炎的典型症状,表明分离到的病毒为Ⅰ型鸭病毒性肝炎病毒(DHV-I)。     

仔猪雷极氏普罗菲登斯菌的分离鉴定及系统进化分析

为了解猪雷极氏普罗菲登斯菌(P.rettgeri)的生物学特性、致病性及16SrRNA基因系统进化关系,从发生严重腹泻、血便的哺乳仔猪群的内脏器官中分离到1株病原菌,根据形态特征、培养特性、生化特性、16SrRNA基因序列分析鉴定为P.rettgeri。小鼠攻毒试验证实,该分离菌株对试验小鼠有较强致病力,哺乳仔猪回归试验可复制出与临床上相似的典型症状,并从发病死亡小鼠及哺乳仔猪中分离到攻毒菌株。系统进化分析表明,分离菌株与雷极氏普罗菲登斯菌系统进化关系最为密切,其16SrRNA基因序列与雷极氏普罗菲登斯菌代表菌株的同源性在97.3%~99.6%之间。药敏试验结果表明,分离菌株对头孢哌酮钠、头孢噻肟钠、头孢曲松钠、头孢唑啉、头孢呋肟、头孢吡肟、阿莫西林、链霉素、氨曲南、诺氟沙星、左氟沙星、恩诺沙星、卡那霉素、氨苄青霉素、米诺环素、链霉素、阿米卡星等多数药物敏感。首次报道了雷极氏普罗菲登斯菌可以引起哺乳仔猪严重腹泻,提示在仔猪腹泻中应注意该菌感染的诊断、监测和防控。     

The impact of weight loss on circulating cytokines in Beagle dogs

Chronic low-grade inflammation in obesity is characterized by an increased production of pro-inflammatory and chemotactic cytokines that are contributing to insulin resistance and related co-morbidities. Cytokines act in networks and exhibit pleiotropic effects so we investigated the circulating levels of a wide array of cytokines (pro and anti-inflammatory, chemotactic and growth factors) in a canine model of weight loss. The dogs served as their own control in order to study the impact of weight loss independent of potential confounding factors, such as history of excess weight or gender. While low-grade inflammation had been previously investigated in obese dogs by measuring changes in adipokines, acute phase proteins and key pro-inflammatory cytokines, to the best of our knowledge this is the first study to evaluate how weight loss impacts a wide array of circulating cytokines.Eighteen overweight Beagle dogs were recruited (six spayed females and 12 neutered males), and none of them were grossly obese according to the body condition score (BCS). All the dogs reached an ideal weight by the end of the program. Parameters were assessed before (baseline), at mid-point (month 3) and at end-point (month 6). Plasma GM-CSF, IL-2, Il-4, IL-6, IL-7, IL-8, IL-10, IL-15, IL-18, IFNγ, IP-10, TNFα, monocyte chemotactic protein 1 (MCP-1), keratinocyte chemokine (KC) were measured with canine multiplex immunoassays. Fat mass was assessed by dual energy X-ray absorption (DEXA).Several cytokines decreased throughout the weight loss program (p < 0.01) and were correlated with the percentage of fat measured by DEXA (p < 0.05): chemotactic (MCP-1), growth factors (GM-CSF, IL-7 and IL-2), and pro-inflammatory (KC and IL-18). We could not show trends for several cytokines, possibly because their level may be lower than the assay sensitivity: anti-inflammatory (IL-4 and IL-10), and pro-inflammatory (IL-6 and TNFα).In conclusion, while our findings for several pro-inflammatory and chemotactic cytokines are in accordance with human and rodent studies, we may have identified additional cytokines, such as growth factors, related to obesity-induced low-grade inflammation. Considering the weight loss was enabled by an adjusted diet, the role of this association of cytokines in insulin resistance and related co-morbidities needs to be clarified. Our results could help better understand the cytokine biology in dogs, and as such are relevant for further elucidating the relationship between immune function and metabolism/nutrition.     

The protoxin Cry1Ac of Bacillus thuringiensis improves the protection conferred by intranasal immunization with Brucella abortus RB51 in a mouse model

Brucellosis is a zoonotic disease affecting many people and animals worldwide. Preventing this infection requires improving vaccination strategies. The protoxin Cry1Ac of Bacillus thuringiensis is an adjuvant that, in addition to increasing the immunogenicity of different antigens, has shown to be protective in different models of parasitic infections. The objective of the present study was to test whether the intranasal co-administration of pCry1Ac with the RB51 vaccine strain of Brucella abortus confers protection against an intranasal challenge with the virulent strain B. abortus 2308 in BALB/c mice. The results showed that co-administration of pCry1Ac and RB51, increased the immunoprotection conferred by the vaccine as evidenced by the following: (1) decrease of the splenic bacterial load when challenged intranasally with the virulent strain; (2) greater in vivo cytotoxic activity in response to the transference of previously infected cells; (3) further proliferation of cytotoxic TCD8+ cells in response to stimulation with heat-inactivated bacteria; (4) increased production of TNF-α and IFN-γ; and (5) significant IgG2a response. These results indicate that the use of the Cry1Ac protein as a mucosal adjuvant via the intranasal route can be a promising alternative for improving current RB51 vaccine against brucellosis.     

Evidence of LAT1 expression in canine caput epididymis

L-type amino acid transporter 1 (LAT1), the first isotype of amino acid transport system L, transports aromatic and branched amino acids pivotal for fundamental cellular activities such cellular growth and proliferation. LAT1 expression was high only in the brain in contrast to its limited distribution and low level of expression in normal tissues. We found potent LAT1 expression in canine caput epididymis by quantitative RT-PCR and Western blotting analysis. Immnuno-histochemical examination revealed observable LAT1 in microvillous epithelial cells.     

Relationship between three novel SNPs of BRCA1 and canine mammary tumors

The BRCA1 gene plays an important role in the development of human breast cancer, and recent research indicated that genetic variations of BRCA1 are also related to canine mammary tumors (CMTs). Here, using rapid amplification of cDNA ends (RACE), we cloned the 5′- and 3′-UTRs of BRCA1. By direct sequencing of the flanking sequences of the 5′- and 3′-UTRs of BRCA1, three previously unreported single-nucleotide polymorphisms (SNPs) were identified, two (−1228T >C, −1173C >T) in the putative promoter regions and one non-synonymous SNP (63449G >A) in exon 23. Compared with 16 normal samples, the sequences from 34 CMTs suggested that SNP (−1173C >T) was associated with the development of CMTs (odds ratio (OR)=2.57, 95% confidence interval (CI): 1.07–6.15).     

Mdivi-1, mitochondrial fission inhibitor,impairs developmental competence and mitochondrial function of embryos and cells in pigs

Mitochondria are highly dynamic organelles that undergo constant fusion/fission as well as activities orchestrated by large dynamin-related GTPases. These dynamic mitochondrial processes influence mitochondrial morphology, size and function. Therefore, this study was conducted to evaluate the effects of mitochondrial fission inhibitor, mdivi-1, on developmental competence and mitochondrial function of porcine embryos and primary cells. Presumptive porcine embryos were cultured in PZM-3 medium supplemented with mdivi-1 (0, 10 and 50 μM) for 6 days. Porcine fibroblast cells were cultured in growth medium with mdivi-1 (0 and 50 μM) for 2 days. Our results showed that the rate of blastocyst production and cell growth in the mdivi-1 (50 μM) treated group was lower than that of the control group (P < 0.05). Moreover, loss of mitochondrial membrane potential in the mdivi-1 (50 μM) treated group was increased relative to the control group (P < 0.05). Subsequent evaluation revealed that the intracellular levels of reactive oxygen species (ROS) and the apoptotic index were increased by mdivi-1 (50 μM) treatment (P < 0.05). Finally, the expression of mitochondrial fission-related protein (Drp 1) was lower in the embryos and cells in the mdivi-1-treated group than the control group. Taken together, these results indicate that mdivi-1 treatment may inhibit developmental competence and mitochondrial function in porcine embryos and primary cells.     

Pathogenicity of emerging Japanese type 1 porcine reproductive and respiratory syndrome virus in experimentally infected pigs

To clarify the pathogenicity of Japanese type 1 porcine reproductive and respiratory syndrome virus (PRRSV) isolate in experimentally infected pigs, we evaluated clinical signs and monitored viremia for 21 days post-inoculation (dpi). Lungs were mottled, tanned and reddish in appearance; had lesions predominantly in the cranial, middle and accessory lobes; and failed to collapse at 10 dpi. Although microscopic lesions of lungs were reproduced using the Japanese emerging type 1 PRRSV isolate under experimental conditions, no significant differences were noted between the challenge and control groups regarding mean rectal temperature and daily weight gain. These results provide useful insights into the limited pathogenicity of single infection with the Japanese type 1 PRRSV isolate in piglets, which differ from findings in reported field cases.