Sialylation of Helicobacter bizzozeronii lipopolysaccharides modulates Toll-like receptor (TLR) 2 mediated response

Sialic acid in lipopolysaccharides (LPS) of mucosal pathogens is known to be an important virulence factor. Few strains of Helicobacter pylori express sialyl-Lewis-X and we have reported that human and canine Helicobacter bizzozeronii strains express sialyl-lactoseamine in their LPS. However, the role of sialyation of Helicobacter LPS in the interaction with the host cells is still unknown. In this study H. bizzozeronii LPS is shown to activate the TLR2 in a dose and strain dependent manner in the in vitro HEK-293 cells model expressing TLR2, but not the cells expressing TLR4. These results indicate that TLR2 is the specific receptor for H. bizzozzeronii LPS, as previously described for H. pylori. To further explore the role of sialylation of H. bizzozeronii LPS on TLR2 response, H. bizzozeronii Δhbs2 mutant strains deficient in sialyltransferase activity were constructed by homologous recombination. LPS from H. bizzozeronii Δhbs2 strains enhanced the NF-ĸB induction via TLR2 compared to the respective wild types, leading to the conclusion that the sialylation of H. bizzozeronii LPS in wild-type strains may modulate host immune response.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-014-0133-4) contains supplementary material, which is available to authorized users.     

Genome sequence of Helicobacter suis supports its role in gastric pathology

ABSTRACT: Helicobacter (H.) suis has been associated with chronic gastritis and ulcers of the pars oesophagea in pigs, and with gastritis, peptic ulcer disease and gastric mucosa-associated lymphoid tissue lymphoma in humans. In order to obtain better insight into the genes involved in pathogenicity and in the specific adaptation to the gastric environment of H. suis, a genome analysis was performed of two H. suis strains isolated from the gastric mucosa of swine. Homologs of the vast majority of genes shown to be important for gastric colonization of the human pathogen H. pylori were detected in the H. suis genome. H. suis encodes several putative outer membrane proteins, of which two similar to the H. pylori adhesins HpaA and HorB. H. suis harbours an almost complete comB type IV secretion system and members of the type IV secretion system 3, but lacks most of the genes present in the cag pathogenicity island of H. pylori. Homologs of genes encoding the H. pylori neutrophil-activating protein and γ-glutamyl transpeptidase were identified in H. suis. H. suis also possesses several other presumptive virulence-associated genes, including homologs for mviN, the H. pylori flavodoxin gene, and a homolog of the H. pylori vacuolating cytotoxin A gene. It was concluded that although genes coding for some important virulence factors in H. pylori, such as the cytotoxin-associated protein (CagA), are not detected in the H. suis genome, homologs of other genes associated with colonization and virulence of H. pylori and other bacteria are present.     

Effects of compounded metronidazole and metronidazole benzoate oral suspensions on food intake in healthy chinchillas (Chinchilla lanigera)

BackgroundThe administration of metronidazole in chinchillas remains controversial and some sources raise concerns regarding drug-induced anorexia or hyporexia. Therefore, the objective of this study was to evaluate if the oral administration of oral metronidazole has a significant effect on food intake in clinically healthy chinchillas, and if drug-induced reduction of food intake differs between metronidazole and metronidazole benzoate as well as between different concentrations of metronidazole benzoate suspensions.MethodsIn a series of randomized, blinded, crossover experiments, the effects of oral administration of metronidaole at 20 mg/kg was evaluated following q12h (for 3 days, n = 12) or q24h (for 5 days, n = 9) dosing using two different drug compounding protocols.ResultsFollowing administration of metronidazole, food intake was significantly reduced within 24 hours of drug administration, regardless of drug formulation type, compounding protocol, or drug concentration. Variation in metronidazole-induced food intake reduction differed widely between individual chinchillas, with a reduction of >50% of food intake reported in 50% of the animals following q12h administration, and 33% of animals after q24h administration of metronidazole. The reduction in food intake was self-limiting and return to normal food intake occurred after discontinuation of metronidazole administration. Neurological adverse effects were observed in one animal following q12h administration.Conclusions and clinical relevanceThe oral administration of metronidazole and metronidazole benzoate at published dosages can result in a marked reduction in food intake, and therefore, this drug should be used cautiously in chinchillas and food intake carefully monitored.     

Cytochrome P450 and its role in veterinary drug interactions.

Cytochrome P450 (CYP) enzymes are common sites of drug interactions in human beings. Drugs may act as inhibitors or inducers of CYPs, leading to altered clearance of a second drug. Clinically relevant drug interactions involving various CYP isoforms in people, including CYP1A2, CYP2C9, CYP2D6, and CYP3A4, have been well documented. Analogous interactions are beginning to be characterized in dogs, for which canine CYPs share many of the same substrate ranges as in human beings.     

Structural and functional characterisation of the ovine interferon gamma (IFNG) gene: its role in nematode resistance in Rasa Aragonesa ewes

The ovine interferon gamma (IFNG) gene was structurally and functionally characterised, and the association between its variants and the response to Haemonchus contortus infection was examined in resistant and susceptible Rasa Aragonesa ewes in different physiological conditions. Sequential faecal egg counts (FECs) were performed on a naturally infected flock of 400 Rasa Aragonesa ewes and two groups of ewes selected for high (n=38) or low (n=33) FEC, which were subsequently challenged with H. contortus in the spring and autumn. The second challenge infection was performed to explore the extent to which the previously established resistance or susceptibility to H. contortus based on FEC reflected the worm burdens of ewes in different physiological states. The ovine IFNG gene was partially isolated and characterised, including the promoter and other regulatory regions. In addition, DNA sequencing of the resistant and susceptible Rasa Aragonesa ewes revealed 13 polymorphisms (12 SNPs and 1 microsatellite) in the IFNG gene. Association studies showed that a haplotype composed of C (SNP -641) and (GTTT)? (microsatellite) was linked to the FEC and worm burden recorded in spring and autumn challenges, respectively, and thus to susceptibility to H. contortus in adult Rasa Aragonesa ewes. Our results also suggested that the IFNG gene was not responsible for the phenotypic variation in susceptibility to H. contortus but was linked to a QTL segregating near the IFNG gene. No significant differences in IFNG gene expression were found between either resistant and susceptible or pregnant and non-pregnant ewes. Finally, we studied the effects of the polymorphisms on IFNG gene expression, finding that the C/T SNP at -641 and the microsatellite showed significant effects in spleen. The C/T SNP at -641 was located within a possible trans-acting factor binding site. Further work is needed to elucidate the function of this SNP.     

The multiple antibiotic resistance (mar) locus and its significance

Chromosomally encoded systems involved in low level resistance of bacteria to different classes of antibiotics (mainly beta-lactams, chloramphenicol, quinolones and tetracycline), disinfectants and in resistance to organic solvents have been the focus of considerable interest in recent years. The multiple antibiotic resistance (mar) locus of Escherichia coli and Salmonella is perhaps the best described system involved in this type of resistance which is induced by MarA, the activator protein encoded by the marRAB locus. The mar -locus is reported to mediate resistance primarily by up-regulating efflux of some antibiotics, disinfectants and organic solvents via the AcrAB-TolC efflux pump and down regulating influx through Outer Membrane Protein F (OmpF). Whilst the level of antibiotic resistance conferred by marRAB is only low level, there are increasing data to suggest that marRAB and related systems are important in clinical antibiotic resistance, possibly as a 'stepping stone' to higher levels of resistance. Other related systems include up-regulation of RobA, SoxS and AcrAB which give rise to a similar resistance phenotype to that conferred by up-regulation of MarA. The aim of this paper is to review the function and significance of the mar -locus and related systems with a particular focus on its implications in veterinary medicine.     

Expression of adiponectin and its receptors (AdipoR1 and AdipoR2) in chicken ovary: potential role in ovarian steroidogenesis

Adiponectin and its receptors (AdipoR1 and AdipoR2) mRNAs are expressed in various chicken tissues including ovary. However, the cellular expression and the role of adiponectin system have never been investigated in chicken ovary. Here, we have shown that the level of adiponectin mRNA is about 10- to 30-fold higher (p < 0.001) in theca cells than in granulosa cells from each hierarchical yellow follicle studied (F4–F1). In contrast, the level of AdipoR1 mRNA expression was about two-fold lower in theca cells than in granulosa cells (p < 0.05) whereas those of AdipoR2 was similar in both ovarian cells. Whereas expression of adiponectin mRNA increased with follicular differentiation in theca cells, it decreased in granulosa cells. In contrast, mRNA expression of AdipoR1 and AdipoR2 in both theca and granulosa cells remained stable during yellow follicle development. To determine whether adiponectin is involved in the ovarian steroidogenesis, LH (100 ng/ml)-, FSH (100 ng/ml)- and IGF-1 (100 ng/ml)-induced progesterone production was measured in absence or presence of human recombinant adiponectin (10 μg/ml) for 36 h in cultured granulosa cells from F1, F2 and mixed F3 and F4 follicles. In absence of LH, FSH and IGF-1, adiponectin treatment had no effects on progesterone production whatever vitollegenic follicle studied. However, it increased by about two-fold IGF-1-induced progesterone secretion in F2 and F3/4 follicles whereas it halved progesterone production in response to gonadotropins (LH and FSH) in F3/4 follicles. Thus, in chicken, adiponectin, mainly expressed in theca cells, could exert paracrine or autocrine effect on the ovarian steroidogenesis.     

Disposition of metronidazole in hens (Gallus gallus) and quails (Coturnix coturnix japonica): pharmacokinetics and whole-body autoradiography

Hens were given single intravenous or oral doses (30 mg/kg body weight) of metronidazole and the plasma concentrations of the drug were determined by high-performance liquid chromatography (HPLC) at intervals from 10 min to 24 h after drug administration. Pharmacokinetic variables were calculated by the Lagrange algorithm technique. The elimination half-life ( t _1/2β) after the intravenous injection was 4.2 ± 0.5 h, the volume of distribution ( V _d(ss)) 1.1±0.2 L/kg and the total body clearance ( Cl _B) 131.2 ± 20 mL/h.kg. Oral bioavailability of the metronidazole was 78 ± 16%. The plasma maximum concentration ( C _max) 31.9 ± 2.3 μg/mL was reached 2 h after the oral administration and the oral elimination half-life ( t ₁/2β) was 4.7 ± 0.2 h. The binding of metronidazole to proteins in hen plasma was very low (less than 3%). Whole body autoradiography of [³H] metronidazole in hens and quails showed an even distribution of labelled material in various tissues at short survival intervals (1-4 h) after oral or intravenous administration. A high labelling was seen in the contents of the small and large intestines. In the laying quails a labelling was also seen in the albumen and in a ring in the periphery of the yolk at long survival intervals. Our results show that a concentration twofold above the MIC is maintained in the plasma of hens for at least 12 h at an oral dose of 30 mg/kg metronidazole.     

挤压技术及其在饲料工业中的应用(1)

前言挤压技术用于食品工业已有近百年历史。按韦氏字典的定义,挤压是“迫使原料通过一个特定设计的开口而成形,事先多将原料预热”。挤压熟化是综合了水、压力、温度和机械剪切的作用完成的。挤压熟化中,机镗内温度可达90￣200℃,挤压延续时间在2￣30s范围。挤压产物会发生一系     

2006年美国饲料市场及分布状况（1）

1 2006年美国饲料产量及其分布 根据对美国动物存栏量的分析,相对应的美国2006年基础饲料生产量略高于2005年.     

Quantification of percutaneous absorption of metronidazole and levamisole in the fire-bellied toad (Bombina orientalis)

Spot-on application has proved to be an effective way to reach therapeutic doses of metronidazole and levamisole in fire-bellied toads. The percutaneous absorption of metronidazole and levamisole was quantified, using an aqueous solution of 1.008 mg/ml of metronidazole and an aqueous solution of 3.767 mg/ml of levamisole. High Performance Liquid Chromatography (HPLC) analysis of the percutaneous absorption revealed that of the amount applied, 75% of metronidazole and 90% of levamisole was absorbed. This resulted during 3 days of application in dosages of 23 mg/kg BW of metronidazole and 94 mg/kg BW of levamisole. Of the absorbed substances, 48% of metronidazole and 9% of levamisole were excreted in urine and faeces as unmetabolised substances.     

Clinical use of metronidazole in horses: 200 cases (1984-1989)

Case records of 200 horses treated with metronidazole were reviewed. Horses were treated for respiratory tract infections (90 cases), peritonitis or abdominal abscess (39 cases), celiotomy (49 cases), orthopedic infections (6 cases), and miscellaneous soft tissue infections (16 cases). Bacteria of the genus Bacteroides were most prevalent (55 of 167 anaerobic isolates). Metronidazole was always used in combination with other antimicrobial drugs. Only 4 of the 200 horses had signs of adverse effects associated with metronidazole treatment. Those 4 horses had poor appetite that resolved when metronidazole treatment was discontinued.     

豌豆抗豌豆象育种及其综合防治研究进展

豌豆是重要的豆科经济作物,世界范围内均有种植,因其营养价值高深受人们喜爱。豌豆象是严重危害豌豆的害虫,全球普遍发生。豌豆象幼虫可蛀食籽粒超过50%的子叶部分,导致籽粒空瘪,发芽率降低,品质变差,商品价值丧失。豌豆象已成为严重制约豌豆产业健康持续发展的因素之一。豌豆栽培种中尚未发现可遗传的豌豆象抗性资源,然而在豌豆近缘野生种中发现了抗性资源,遗传研究表明3对隐性基因控制豆象抗性。α-淀粉酶抑制剂(α-amylase inhibitor,α-AI)和豌豆neoplastic pod(Np)基因突变体植株可有效减轻豌豆象危害。豌豆转基因抗虫育种虽然已获成功,但由于安全性问题,目前唯一有效的防治方法仍然是化学药剂的使用。为了解和掌握豌豆象最新研究前沿动态,促进豌豆象有效防治,本研究从豌豆象、豌豆抗豆象及豌豆象综合防治等3方面研究进展进行了综述。基于此,指出我国目前研究中存在的问题,并提出豌豆象、豌豆抗豆象育种及其综合防治领域未来的研究重点和方向。     

家蚕丝素结晶区高度重复多肽[GAGAGA]_(16)和[GAGAGS]_(16)的融合蛋白优化表达

为了给深入研究家蚕丝素结晶区的典型肽段结构提供素材,对设计的GST-tag家蚕丝素结晶区典型多肽[GAGAGA]16和[GAGAGS]16的融合蛋白KGA、KGS进行了表达条件优化试验。结果表明,pGEX-KGA和pGEX-KGS表达载体能够有效表达家蚕丝素结晶区的2种典型多肽,KGA和KGS的最佳表达诱导剂IPTG的浓度分别为1.4mmol/L、1.0 mmol/L,诱导时间为5 h。在此优化条件下,KGA和KGS在大肠杆菌(E.coli)中的表达量分别达75 mg/L、110 mg/L。诱导起始时大肠杆菌的菌密度(OD600为0.4~3.0)对2种融合蛋白的表达效率没有显著影响。     

Pharmacokinetics of metronidazole and its concentration in body fluids and endometrial tissues of mares.

Serum concentrations of metronidazole were determined in 6 healthy adult mares after a single IV injection of metronidazole (15 mg/kg of body weight). The mean elimination rate (K) was 0.23 h-1, and the mean elimination half-life (t1/2) was 3.1 hours. The apparent volume of distribution at steady state was 0.69 L/kg, and the clearance was 168 ml/h/kg. Each mare was then given a loading dose (15 mg/kg) of metronidazole at time 0, followed by 4 maintenance doses (7.5 mg/kg, q 6 h) by nasogastric tube. Metronidazole concentrations were measured in serial samples of serum, synovia, peritoneal fluid, and urine. Metronidazole concentrations in CSF and endometrial tissues were measured after the fourth maintenance dose. The highest mean concentration in serum was 13.9 +/- 2.18 micrograms/ml at 40 minutes after the loading dose (time 0). The highest mean synovial and peritoneal fluid concentrations were 8.9 +/- 1.31 micrograms/ml and 12.8 +/- 3.21 micrograms/ml, respectively, 2 hours after the loading dose. The lowest mean trough concentration in urine was 32 micrograms/ml. Mean concentration of metronidazole in CSF was 4.3 +/- 2.51 micrograms/ml and the mean concentration in endometrial tissues was 0.9 +/- 0.48 micrograms/g at 3 hours after the fourth maintenance dose. Two mares hospitalized for treatment of bacterial pleuropneumonia were given metronidazole (15.0 mg/kg, PO, initially then 7.5 mg/kg, PO, q 6 h), while concurrently receiving gentamicin, potassium penicillin, and flunixin meglumine IV. Metronidazole pharmacokinetics and serum concentrations in the sick mares were similar to those obtained in the healthy mares.     

Increased expression of fractalkine and its receptor CX(3)CR1 in canine inflammatory bowel disease and their possible role in recruitment of intraepithelial lymphocytes

The interaction between fractalkine/CX(3)CL1 and its receptor CX(3)CR1 has been reported to play an important role in various human inflammatory diseases, including inflammatory bowel disease (IBD) mediated by lymphocyte chemoattraction. The objective of this study was to investigate the role of fractalkine and CX(3)CR1 in lymphocyte migration in canine IBD. IBD was diagnosed in 34 dogs, and 19 healthy beagles were used as normal controls. We quantified intestinal mRNA and protein expression of fractalkine and CX(3)CR1 by real-time RT-PCR and ELISA, respectively, and examined the localization of fractalkine in canine intestine by immunohistochemistry. The expression of CX(3)CR1 and surface antigens on peripheral blood mononuclear cells (PBMCs) and intraepithelial lymphocytes (IELs) was analyzed by flow cytometry. Intestinal fractalkine and CX(3)CR1 mRNA was significantly up-regulated in IBD dogs compared with the healthy control dogs. In addition, fractalkine expression on intestinal epithelial cells was significantly increased in the intestinal mucosa of IBD dogs compared with the healthy dogs. CX(3)CR1(+) PBMCs were significantly elevated in IBD dogs and positively correlated with the histopathological severity of IELs infiltration. These CX(3)CR1(+) PBMCs predominantly expressed markers for cytotoxic T cells. Almost all IELs expressed CD3, and the majority of cells expressed CD8 rather than CD4, which was analogous to the CX(3)CR1(+) PBMCs. These results suggest that the fractalkine-CX(3)CR1 interaction may contribute to the pathogenesis of canine IBD through migration of IELs.     

Cytochrome P450 (CYP1A) induction in sea bream (Sparus Aurata) gills and liver following exposure to polychlorobiphenyls (PCBs)

Veterinary Research Communications -     

家蚕丝素结晶区典型多肽[GAGAGY]_(16)和[GAGAGV]_(16)的融合蛋白优化表达

家蚕丝素结晶区典型多肽[GAGAGY]16、[GAGAGV]16的GST融合蛋白KGY和KGV是深入研究家蚕丝素结晶区典型多肽聚集态结构的素材。对这2种融合蛋白在大肠杆菌中的表达条件进行优化试验的结果表明,表达载体pGEX-KGY和pGEX-KGV能够有效表达家蚕丝素结晶区的这2种典型多肽。KGY和KGV的最佳诱导表达条件:IPTG浓度分别为0.2 mmol/L和1.0 mmol/L,诱导时间分别为5 h和4 h。在此条件下,2种融合蛋白在大肠杆菌中的表达量分别达115 mg/L和90 mg/L左右。诱导起始时大肠杆菌的菌密度(OD600为0.4～3.0)对2种融合蛋白的表达效率没有显著影响。