Screening and evaluation of antigens for detection of antibodies against Mycobacterium avium subspecies paratuberculosis in naturally infected young sheep / 中国生物制品学杂志

@#Objective To analyze the antibody responses of 10 serum reactive antigens(MAP1138c,MAP2121c,MAP0150c,MAP0862,MAP0209c,MAP2120c,MAP0038,MAP3420c,MAP 2154c and MAP2751)of Mycobacterium avium subspecies paratuberculosis(MAP)in naturally infected young sheep and evaluate their diagnostic value.Methods Serum samples and anal swab samples were collected from 6-month-old sheep without obvious PTB symptoms in the flocks with paratuberculosis(PTB)history.The serum samples were tested by PTB antibody detection ELISA kit,and anal swab samples were detected by the fluorescent quantitative PCR based on MAP F57 element.The sheep were grouped according to the test results.PCR was used to detect 10 MAP antigen genes in positive anal swabs.The antigen genes were cloned into pET-28a and induced to be expressed in E.coli BL21(DE3)strain by IPTG.The recombinant antigens were purified by Ni-Sepharose,and then coated on the ELISA plate for testing the collected serum samples to analyze the antibody reaction of the selected antigens in naturally infected sheep.The detection rates of serum antibodies against different antigens were analyzed to evaluate the diagnostic value of the antigens.Results The 72 sheep sampled were divided into three groups:anal swab positive-antibody positive(n = 34),anal swab positive-antibody negative(n = 23),and anal swab negative-antibody negative(n = 15).All 10 antigen genes were detected from positive anal swabs,and sequences of each gene were highly consistent.Through ELISA detection,MAP1138c,MAP2121c,MAP0150c and MAP0862 produced antibody reactions in infe-cted sheep.Antibodies against MAP1138c,MAP2121c,MAP0150c and MAP0862 were detected in 30,34,24 and 31 of the 57infected sheep,respectively.In the anal swab positive-antibody positive group,the detection rate of anti-MAP1138c antibody was the highest(76.47%).In the anal swab positive-antibody negative group,the detection rates of antibodies against MAP2121 and MAP0862(52.17% and 47.83%)were higher than those of the other two proteins.In the detection of 72serum samples,the overlap of ELISA coated with MAP2121c and MAP0862 exceeded 91%.Conclusion MAP1138c,MAP-2121c and MAP0862 may be dominant biomarkers to induce MAP antibody response in naturally infected young sheep.MAP2121c and MAP0862 can make up for the deficiency of sensitivity of commercial ELISA kits in early diagnosis of PTB.

Identification and anti-infection effect of heparin binding motif of sacbrood virus capsid protein / 中国生物制品学杂志

@#Objective To identify the heparin-binding motif of drug-binding pocket protein 2(Dbpp2)of sacbrood virus(SBV)and determine the anti-SBV infection activity of the heparin-binding motif and its derived peptides.MethodsThe secondary structure prediction and homology modeling of Dbpp2 were carried out using online software to search for potential heparin-binding motifs. The binding ability of SBV,Dbpp2 and their heparin-binding motif mutants to and the ability of heparin-binding motifs to inhibit the binding of Dbpp2 to heparin were tested using heparin agarose beads. The therapeutic effect of heparin-binding motifs and their derived peptides on the larvae of Apis cerana cerana infected with SBV was tested.ResultsSBV and Dbpp2 showed binding with heparin. The flexible ring(KPANRPRR)rich in basic amino acids exposed at the C-end of Dbpp2 was a heparin-binding motif,which inhibited Dbpp2 from binding to heparin. KPANRPRR and its derived peptides KPAARPRR,KPRNRPRR,KPRARPRR,KPRWRPRR and KPRWRPRRW all had the effect of reducing the mortality of larvae caused by SBV infection,among which KPRARPRR showed the best therapeutic effect.Conclusion The research provides a basis for understanding the interaction of SBV-glycosaminoglycan(GAG),and provides a reference for the development of peptides for the treatment of SBV infection based on the interaction.

Identification of Mycobacterium avium subspecies paratuberculosis in sheep farms in Bayannaoer, Inner Mongolia, China (short communication).

BACKGROUND: Paratuberculosis is a widespread chronic infection of Mycobacterium avium subspecies paratuberculosis (MAP) that causes significant economic losses to the sheep industry. The current study investigated this disease, which causes diarrhea in sheep, particularly, in Bayannaoer, Inner Mongolia, China. Diagnosis was based on clinical symptoms, pathological autopsy, histopathological inspection, and serological and molecular methods. RESULTS: MAP was confirmed using polymerase chain reaction using DNA extracted from tissue and fecal samples. Serum samples from 472 individual sheep were obtained to detect antibodies against MAP using an enzyme-linked immunosorbent assay. MAP antibodies were separately detected in 17.86% (35/196) and 18.48% (51/276) of sheep herds at approximately 6 months and ≥ 1 year of age, respectively. The tissue lesion and pathological section results were consistent with paratuberculosis infection. CONCLUSIONS: To our knowledge, this is the first report of Mycobacterium avium subspecies paratuberculosis seroprevalence in Bayannaoer sheep in Inner Mongolia. Our findings show that MAP is not only prevalent, but also a potential threat to this region. Further investigations, including long-term epidemiological surveillance and isolation are needed for the awareness and effective treatment of paratuberculosis in sheep of Inner Mongolia.

Complete Genome Sequence of Trueperella pyogenes, Isolated from Infected Farmland Goats.

Trueperella pyogenes is a significant pathogen of livestock, causing diverse diseases, such as mastitis, liver abscessation, and pneumonia. In this study, we have reported the genome sequence of Trueperella pyogenes 2012CQ-ZSH. Moreover, several genes coding for virulence factors were found, such as pyolysin (PYO), nanH, nanP, cbpA, fimC, and fimE.

Rapid detection of sacbrood virus (SBV) by one-step reverse transcription loop-mediated isothermal amplification assay.

BACKGROUND: Sacbrood virus (SBV) primarily infects honeybee broods, and in order to deal with the problem cost effective detection methods are required. FINDINGS: A one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for the rapid identification of SBV. The data demonstrated that, in a simple water bath, SBV RNA could be detected as early as 20 min at 65°C, and a positive amplification reaction was visible to the naked eye due to a color change brought on by the addition of nucleic acid stain SYBR Green. CONCLUSIONS: The current study presents a method for the rapid and simple detection of SBV by RT-LAMP with high sensitivity and analytic specificity.

Low doses of cyclic AMP-phosphodiesterase inhibitors rapidly evoke opioid receptor-mediated thermal hyperalgesia in naïve mice which is converted to prominent analgesia by cotreatment with ultra-low-dose naltrexone.

Systemic (s.c.) injection in naïve mice of cyclic AMP-phosphodiesterase (cAMP-PDE) inhibitors, e.g. 3-isobutyl-1-methylxanthine [(IBMX) or caffeine, 10 mg/kg] or the more specific cAMP-PDE inhibitor, rolipram (1 mug/kg), rapidly evokes thermal hyperalgesia (lasting >5 h). These effects appear to be mediated by enhanced excitatory opioid receptor signaling, as occurs during withdrawal in opioid-dependent mice. Cotreatment of these mice with ultra-low-dose naltrexone (NTX, 0.1 ng/kg-1 pg/kg, s.c.) results in prominent opioid analgesia (lasting >4 h) even when the dose of rolipram is reduced to 1 pg/kg. Cotreatment of these cAMP-PDE inhibitors in naïve mice with an ultra-low-dose (0.1 ng/kg) of the kappa-opioid receptor antagonist, nor-binaltorphimine (nor-BNI) or the mu-opioid receptor antagonist, beta-funaltrexamine (beta-FNA) also results in opioid analgesia. These excitatory effects of cAMP-PDE inhibitors in naïve mice may be mediated by enhanced release of small amounts of endogenous bimodally-acting (excitatory/inhibitory) opioid agonists by neurons in nociceptive networks. Ultra-low-dose NTX, nor-BNI or beta-FNA selectively antagonizes high-efficacy excitatory (hyperalgesic) Gs-coupled opioid receptor-mediated signaling in naïve mice and results in rapid conversion to inhibitory (analgesic) Gi/Go-coupled opioid receptor-mediated signaling which normally requires activation by much higher doses of opioid agonists. Cotreatment with a low subanalgesic dose of kelatorphan, an inhibitor of multiple endogenous opioid peptide-degrading enzymes, stabilizes endogenous opioid agonists released by cAMP-PDE inhibitors, resulting in conversion of the hyperalgesia to analgesia without requiring selective blockade of excitatory opioid receptor signaling. The present study provides a novel pharmacologic paradigm that may facilitate development of valuable non-narcotic clinical analgesics utilizing cotreatment with ultra-low-dose rolipram plus ultra-low-dose NTX or related agents.

Naloxone rapidly evokes endogenous kappa opioid receptor-mediated hyperalgesia in naïve mice pretreated briefly with GM1 ganglioside or in chronic morphine-dependent mice.

Low-dose naloxone-precipitated withdrawal hyperalgesia is a reliable indicator of physical dependence after chronic morphine treatment. A remarkably similar long-lasting (>3-4 h) hyperalgesia is evoked by injection of a low dose of naloxone (10 microg/kg, s.c.) in naïve mice after acute pretreatment with the glycolipid, GM1 ganglioside (1 mg/kg) (measured by warm-water-immersion tail-flick assays). GM1 treatment markedly increases the efficacy of excitatory Gs-coupled opioid receptor signaling in nociceptive neurons. Co-treatment with an ultra-low-dose (0.1 ng/kg, s.c.) of the broad-spectrum opioid receptor antagonist, naltrexone or the selective kappa opioid receptor antagonist, nor-binaltorphimine, blocks naloxone-evoked hyperalgesia in GM1-pretreated naïve mice and unmasks prominent, long-lasting (>4 h) inhibitory opioid receptor-mediated analgesia. This unmasked analgesia can be rapidly blocked by injection after 1-2 h of a high dose of naltrexone (10 mg/kg) or nor-binaltorphimine (0.1 mg/kg). Because no exogenous opioid is administered to GM1-treated mice, we suggest that naloxone may evoke hyperalgesia by inducing release of endogenous bimodally acting opioid agonists from neurons in nociceptive networks by antagonizing putative presynaptic inhibitory opioid autoreceptors that "gate" the release of endogenous opioids. In the absence of exogenous opioids, the specific pharmacological manipulations utilized in our tail-flick assays on GM1-treated mice provide a novel bioassay to detect the release of endogenous bimodally acting (excitatory/inhibitory) opioid agonists. Because mu excitatory opioid receptor signaling is blocked by ultra-low doses of naloxone, the higher doses of naloxone that evoke hyperalgesia in GM1-treated mice cannot be mediated by activation of mu opioid receptors. Co-treatment with ultra-low-dose naltrexone or nor-binaltorphimine may selectively block signaling by endogenous GM1-sensitized excitatory kappa opioid receptors, unmasking inhibitory kappa opioid receptor signaling, and converting endogenous opioid receptor-mediated hyperalgesia to analgesia. Co-treatment with kelatorphan stabilizes putative endogenous opioid peptide agonists released by naloxone in GM1-treated mice, so that analgesia is evoked rather than hyperalgesia. Acute treatment of chronic morphine-dependent mice with ultra-low-dose naltrexone (0.1 ng/kg) results in remarkably similar rapid blocking of naloxone (10 microg/kg)-precipitated withdrawal hyperalgesia and unmasking of prominent opioid analgesia. These studies may clarify complex mechanisms underlying opioid physical dependence and opioid addiction.