Serological investigation and genotyping of Mycobacterium avium subsp. paratuberculosis in sheep and goats in Inner Mongolia, China.

Paratuberculosis a contagious and chronic disease in domestic and wild ruminants, is caused by Mycobacterium avium subspecies paratuberculosis (MAP). Typical clinical signs include intractable diarrhea, progressive emaciation, proliferative enteropathy, and mesenteric lymphadenitis. Paratuberculosis is endemic to many parts of the world and responsible for considerable economic losses. In this study, different types of paratuberculosis and MAP in sheep and goats were investigated in Inner Mongolia, a northern province in China contiguous with two countries and eight other provinces. A total of 4434 serum samples were collected from six cities in the western, central, and eastern regions of Inner Mongolia and analyzed using the ELISA test. In addition, tissue samples were collected from seven animals that were suspected to be infected with MAP. Finally, these tissues samples were analyzed by histopathological examination followed by polymerase chain reaction (PCR), IS1311 PCR-restriction enzyme analysis (PCR-REA), and a sequence analysis of five genes. Among all 4434 ruminant serum samples collected from the six cities in the western, central, and eastern regions of Inner Mongolia, 7.60% (337/4434) measured positive for the MAP antibody. The proportions of positive MAP antibody results for serum samples collected in the western, central, and eastern regions were 5.10% (105/2058), 6.63% (85/1282), and 13.44% (147/1094), respectively. For the seven suspected infected animals selected from the herd with the highest rate of positivity, the gross pathology and histopathology of the necropsied animals were found to be consistent with the pathological features of paratuberculosis. The PCR analysis further confirmed the diagnosis of paratuberculosis. The rest of the results demonstrated that herds of sheep and goats in Inner Mongolia were infected with both MAP type II and type III. To the best of our knowledge, this is the first study of the two subtypes of MAP strains in sheep and goats in Inner Mongolia.

Isobavachalcone inhibits post-entry stages of the porcine reproductive and respiratory syndrome virus life cycle.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a pathogen of great economic significance that impacts the swine industry globally. Since the first report of a porcine reproductive and respiratory syndrome (PRRS) outbreak, tremendous efforts to control this disease, including various national policies and plans incorporating the use of multiple modified live-virus vaccines, have been made. However, PRRSV is still a significant threat to the swine industry, and new variants continually emerge as a result of PRRSV evolution. Several studies have shown that pandemic PRRSV strains have enormous genetic diversity and that commercial vaccines can only provide partial protection against these strains. Therefore, effective anti-PRRSV drugs may be more suitable and reliable for PRRSV control. In this study, we observed that isobavachalcone (IBC), which was first isolated from Psoralea corylifolia, had potent anti-PRRSV activity in vitro. Although many biological activities of IBC have been reported, this is the first report describing the antiviral activity of IBC. Furthermore, after a systematic investigation, we demonstrated that IBC inhibits PRRSV replication at the post-entry stage of PRRSV infection. Thus, IBC may be a candidate for further evaluation as a therapeutic agent against PRRSV infection of swine in vivo.

Enhancement of bacteriolysis of shuffled phage PhiX174 gene E.

Bacterial ghosts that are generated using the regulated PhiX174 lysis gene E offer a new avenue for the study of inactivated vaccines. Here, we constructed a library of mutant gene E using a gene-shuffling technique. After screening and recombination with the prokaryotic non-fusion expression vector pBV220, two lysis plasmids were selected. Among which, a novel mutant E gene (named mE), consisting of a 74-bp non-encoding sequence at 5'-end and a 201-bp gene ΔE, significantly increased the lysis effect on prokaryotic Escherichia coli and Salmonella enteritidis. Moreover, lysis efficiency, as measured by the OD600 value, reached 1.0 (109 CFU), avoiding the bottleneck problem observed with other bacterial lysis procedures, which results in a low concentration of bacteria in suspension, and consequent low production of bacterial ghosts. Our results may provide a promising avenue for the development of bacterial ghost vaccines.

Serotypes, virulence genes, and antimicrobial susceptibility of Escherichia coli isolates from pigs.

One hundred two pathogenic Escherichia coli isolates from diseased pigs were analyzed for serotypes, virulence genes, antimicrobial susceptibility, and the molecular basis of phenicol resistance. Of these 102 E. coli isolates, 101 were typeable and belonged to 27 different O serogroups. However, 69% of these isolates belonged to one of the following eight serogroups: O8, O54, O64, O65, O92, O108, O119, and O120. Serogroups O8 (23%) and O64 (10%) were the most prevalent among typeable isolates. High-resistance phenotypes were observed in all the isolates, with the majority displaying resistance to chloramphenicol (89%), streptomycin (83%), enrofloxacin (78%), and doxycycline (60%). The chloramphenicol resistance genes cat1, cat2, and cmlA were detected in 58%, 49%, and 65%, respectively, of the chloramphenicol-resistant isolates. The floR gene was detected in 57% of the florfenicol-resistant isolates and in 52% of chloramphenicol-resistant isolates. Pulsed-field gel electrophoresis showed that the 32 floR-positive isolates with florfenicol minimum inhibitory concentration ≥ 8 µg mL⁻¹ belonged to 25 different pulsed-field gel electrophoresis profiles, indicating the spread of floR among swine pathogenic E. coli isolates.

Isolation and characterization of human anti-VEGF165 monoclonal antibody with anti-tumor efficacy from transgenic mice expressing human immunoglobulin loci.

The purpose of this study was to prepare a fully human anti-VEGF (vascular endothelial growth factor) monoclonal antibody with anti-tumor activity from five-feature mice which express human immunoglobin loci. Four hybridomas secreting mAb stably were isolated successfully. Some characters such as isotypes, cross-reactivity, inhibition on the binding of hVEGF to VEGFR-2, dissociation constants and the idiotypic characteristic were determined. Proliferation of T24 and Ls-174-T cell line and nude mice bearing human colorectal cancer were used to evaluate therapeutic effects and safety of this mAb. Pharmacokinetics data shows the half life of this mAb was about 5 days after a single intravenous injection. These results suggest the fully human anti-VEGF mAb maybe safe and efficient for cancer treatment.

Transfer of an expression YAC into goat fetal fibroblasts by cell fusion for mammary gland bioreactor.

Yeast artificial chromosomes (YACs) as transgenes in transgenic animals are likely to ensure optimal expression levels. Microinjection of YACs is the exclusive technique used to produce YACs transgenic livestock so far. However, low efficiency and high cost are its critical restrictive factors. In this study, we presented a novel procedure to produce YACs transgenic livestock as mammary gland bioreactor. A targeting vector, containing the gene of interest-a human serum albumin minigene (intron 1, 2), yeast selectable marker (G418R), and mammalian cell resistance marker (neo(r)), replaced the alpha-lactalbumin gene in a 210kb human alpha-lactalbumin YAC by homogeneous recombination in yeasts. The chimeric YAC was introduced into goat fetal fibroblasts using polyethylene glycol-mediated spheroplast fusion. PCR and Southern analysis showed that intact YAC was integrated in the genome of resistant cells. Perhaps, it may offer a cell-based route by nuclear transfer to produce YACs transgenic livestock.

Effect of human osteopontin on proliferation, transmigration and expression of MMP-2 and MMP-9 in osteosarcoma cells.

BACKGROUND: To explore the effect of human osteopontin (hOPN) on the proliferation, transmigration and expression of matrix metallproteinase-2 (MMP-2) and matrix metallproteinase-9 (MMP-9) in osteosarcoma (OS) cells in vitro. METHODS: The prokaryotic-expression vector of hOPN was produced. hOPN was then subcloned into E. coli BL21 (DE3) cells and purified with ProBond trade mark Columns. The proliferation, cell cycle and the expression of cyclin A in OS cells were investigated by using MTT assay, flow cytometry and Western blot respectively. The transmigration of OS cells was checked by using transwell cell culture chamber. The micro-pore-filter-membrane system was used to study the chemiotaxis of hOPN to OS cells. The levels of total protein were examined according to Coomassie Brilliant Blue manuals. The expression of MMP-2 and MMP-9 were evaluated by detecting the volume of degradation of gelatin on SDS-PAGE gel. RESULTS: The prokaryotic-expression vector of hOPN and purified hOPN protein were achieved hOPN promoted OS cells proliferation in a dose-dependent manner, and stimulated cyclin A expression in OS cells to accelerate cell division cycle. hOPN facilitated the trans-membrane migration of OS cells. hOPN also enhanced the secretion of MMP-2 and MMP-9 in OS cells. CONCLUSION: hOPN could stimulate cyclin A expression in OS cells. hOPN has chemiotaxis to OS cells and increases their transmigration. hOPN enhances the secretion of MMP-2 and MMP-9 in OS cells.