Bacterial lipopolysaccharide induces porcine circovirus type 2 replication in swine alveolar macrophages   总被引：5，自引：0，他引：5  

Chang HW  Pang VF  Chen LJ  Chia MY  Tsai YC  Jeng CR 《Veterinary microbiology》2006,115(4):311-319

Monocyte/macrophage lineage cells are major target cells of porcine circovirus type 2 (PCV2). From tissues of field pigs suffering from postweaning multisystemic wasting syndrome (PMWS), both intracytoplasmic and intranuclear PCV2 signals, including antigens and nucleic acid, were easily detected in the monocyte/macrophage lineage cells. However, there was a high incidence of intracytoplasmic PCV2-positive signals, but lack of intranuclear signals and PCV2 replication in these cells in vitro. Concurrent infection with bacteria and activation of immune system are suggested to promote viral replication. In this study, lipopolysaccharide (LPS) and phorbol-12-myristate-13-acetate (PMA) were used to stimulate PCV2-inoculated alveolar macrophages (AMs). A decrease in intracytoplasmic but increase in intranuclear PCV2-positive signals, including antigens and nucleic acid, were detected in LPS-treated PCV2-inoculated AMs, but not in PMA-treated cells. Additionally, the replication product corresponding to PCV2 spliced major capsid protein (Cap) mRNA and a significant elevation in PCV2 titer were demonstrated in the LPS-treated PCV2-inoculated AMs. The results imply that Gram-negative bacterial co-infection in PCV2-infected pigs may be an important factor in promoting PCV2 replication and contributing, at least partially, to the full development of PMWS.  相似文献   

Apoptosis and oxidative stress of infiltrated neutrophils obtained from mammary glands of goats during various stages of lactation     

Su WJ  Chang CJ  Peh HC  Lee SL  Huang MC  Zhao X 《American journal of veterinary research》2002,63(2):241-246

OBJECTIVE: To examine apoptosis in infiltrated neutrophils during involution of mammary glands and compare them with those obtained during late and peak lactation, and to measure oxidative stress and activities of antioxidant enzymes and determine involvement of free radicals in apoptosis of infiltrated neutrophils. SAMPLE POPULATION: Neutrophils from mammary gland secretions of 8 goats at 4 stages (late and peak lactation and 1 and 2 weeks after end of lactation). PROCEDURE: DNA fragmentation was evaluated to characterize apoptosis. Concentration of thiobarbituric acid reactive substances (TBARS) was used to evaluate oxidative stress. Activities of superoxide dismutase and glutathione peroxidase were determined. RESULTS: Neutrophils from secretions obtained after end of lactation of all goats and from late-lactation milk of some goats underwent prominent apoptosis, whereas neutrophils from peak lactation secretions did not. Higher lipid peroxidation and lower antioxidant enzyme activities in neutrophils during involution were observed, compared with those during late and peak lactation. A significant negative correlation existed between TBARS concentrations and antioxidant enzyme activities during the nonlactating period. CONCLUSIONS AND CLINICAL RELEVANCE: Apoptosis is a feature of infiltrated neutrophils during involution of mammary glands in goats. This feature may allow prompt resorption and clearance of infiltrated neutrophils without damaging surrounding tissues. Increased oxidative stress in infiltrated neutrophils from secretions obtained after end of lactation is probably related to a deficiency in antioxidant enzyme activities. Understanding the relationship between apoptosis and oxidative stress will lead to new strategies for manipulating involution and reducing tissue damage.  相似文献   

Starch‐like exopolysaccharide produced by the filamentous fungi Ophiostoma ulmi and O. novo‐ulmi     

R. Jeng  C. Huang  M. Sain  M. Hubbes  A. Rodriguez  B. Saville 《Forest Pathology》2007,37(2):80-95

This paper describes the chemical and biochemical properties of exopolysaccharides (EPS) produced by Ophiostoma ulmi and O. novo‐ulmi isolates, the Dutch elm disease (DED) fungi. Some of EPS have been considered as pathogenicity factor in the DED complex. The selected isolates grow well and produce EPS in a medium containing various types of carbon and nitrogen sources. EPS obtained from potato dextrose broth (PDB) medium appeared to be opaque, firm and stained purple blue with iodine‐potassium iodide solution, whereas those from yeast extract (YE) medium were less opaque, jelly‐like and remained unchanged in iodine solution. The selected fungal isolates produced much higher molecular weight EPS from the medium containing YE than from PDB. The results of this study suggest that high molecular weight compounds produced by O. ulmi (W9) and O. novo‐ulmi (R136) are not involved in DED pathogenesis. Spectrometric analysis of acid‐digested EPS obtained from PDB and YE revealed the presence of a monomer similar to glucose used as a standard. Thin layer chromatography indicated that glucan‐1,4‐α‐glucosidase (glucoamylase) only hydrolyses EPS from PDB media and releases glucose. The results strongly indicate that isolates of O. ulmi and O. novo‐ulmi produce starch‐like EPS from PDB medium. The EPS obtained from YE medium lacked this characteristic. The biological significance and the potential use of these EPS are discussed.  相似文献   

Association of zinc with connective tissue in the digestive tract of common carp     

Hsuan-Jung Liao  Yen-Hua Chen  Sen-Shyong Jeng 《Fisheries Science》2006,72(4):893-902

ABSTRACT:   Zinc (Zn) concentration in the digestive tract of common carp is always >10 times higher than most animal tissues. In a previous paper, it was reported that this high Zn came from a 43 kDa Zn-binding membrane protein. In this present study it was further found that in the digestive tract of common carp, Zn content was closely associated with the amounts of extracellular macromolecules. The higher the Zn content, the more there is of collagen and glycosaminoglycans. An indirect immunoperoxidase staining method using antibody against the 43 kDa Zn-binding protein, or the fibroblast marker (Thy 1.1 protein) was applied to the sections of digestive tract of fish. It was found that the Zn-binding protein in the digestive tract of common carp is mainly located in the connective tissue of its lamina propria and submucosal layer. Connective tissue cells, probably fibroblasts, hold the 43 kDa Zn-binding protein. In the common carp Zn might be bound to the external side of the fibroblast. The present finding may have a significant meaning on extending the studies of Zn in biology to the field of Zn with extracellular matrix.  相似文献   

Seasonal variations of free amino acids and nucleotide-related compounds in the muscle of cultured Taiwanese puffer Takifugu rubripes   总被引：2，自引：0，他引：2  

Deng-Fwu Hwang  Tai-Yuan Chen  Chyuan-Yuan Shiau and  Sen-Shyong Jeng 《Fisheries Science》2000,66(6):1123-1129

SUMMARY: Seasonal variation in the level of extractive nitrogenous components was investigated in the muscle of puffer Takifugu rubripes cultured in two different areas of Taiwan. There were no seasonal and regional variations in the proximate composition of the fish. Of the free amino acids (FAA) in the muscle of puffer, the predominant one was taurine, followed by glycine, lysine, and alanine. Among nucleotide-related compounds, inosine monophosphate (IMP) and guanosine monophosphate (GMP) were the most prominent compounds. The total nucleotide-related compounds in the muscle of puffer were higher in July and November than those in the other months. The level of total taste-active components including glycine, alanine, arginine, GMP, IMP, and adenosine 5'-monophosphate was much higher in the muscle of puffer collected from July to January. Therefore, the puffer is probably more palatable in these periods.  相似文献   

A cholesterol biosynthesis inhibitor blocks Staphylococcus aureus virulence     

Liu CI  Liu GY  Song Y  Yin F  Hensler ME  Jeng WY  Nizet V  Wang AH  Oldfield E 《Science (New York, N.Y.)》2008,319(5868):1391-1394

Staphylococcus aureus produces hospital- and community-acquired infections, with methicillin-resistant S. aureus posing a serious public health threat. The golden carotenoid pigment of S. aureus, staphyloxanthin, promotes resistance to reactive oxygen species and host neutrophil-based killing, and early enzymatic steps in staphyloxanthin production resemble those for cholesterol biosynthesis. We determined the crystal structures of S. aureus dehydrosqualene synthase (CrtM) at 1.58 angstrom resolution, finding structural similarity to human squalene synthase (SQS). We screened nine SQS inhibitors and determined the structures of three, bound to CrtM. One, previously tested for cholesterol-lowering activity in humans, blocked staphyloxanthin biosynthesis in vitro (median inhibitory concentration approximately 100 nM), resulting in colorless bacteria with increased susceptibility to killing by human blood and to innate immune clearance in a mouse infection model. This finding represents proof of principle for a virulence factor-based therapy against S. aureus.  相似文献   

Potential nitrogen and phosphorus leaching from soils fertilized with meat and bone meal     

Alhaji S. Jeng  Nils Vagstad 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):238-245

Abstract

The nitrogen and phosphorus contents of meat and bone meal (MBM) make it a potentially valuable nutrient source in agriculture. Its narrow N:P ratio, however, makes it a potential environmental risk if it is not utilized with caution. A column-leaching experiment was conducted to assess potential nitrogen and phosphorus leaching from bare soils fertilized with MBM. This should give an idea of the efficacy of autumn or early spring MBM application on land devoid of vegetation cover. Earlier greenhouse and field experiments have indicated that nitrogen mineralization after MBM application takes place relatively rapidly. The column experiment conducted here has indicated that spring application of MBM prior to planting can result in the loss of mineral nitrogen, reducing the total amount of N available to the crop. A higher initial loss (up to 47 mg l^?1) of ammonium was found for the MBM treated soils, but this declined to less than 0.1 mg l^?1 by the end of the experiment, 11 weeks later. Nitrate loss was highest at the onset of the experiment for the soils that received mineral N fertilizer. With time, however, the largest nitrate losses were associated with the MBM-treated soils. Nitrate leaching continued to well beyond the end of the experiment. The effect will most certainly be exacerbated when the crop N (rather than crop P) requirement forms the basis for MBM application. The amount of P leached as ortho-P is probably small but may also represent an environmental risk if N remains to be the basis of MBM application. Based on the results presented here and considering the dangers of elevated nutrient losses, autumn and early spring MBM application may not be recommended.  相似文献   

Study of Biochar Properties by Scanning Electron Microscope – Energy Dispersive X-Ray Spectroscopy (SEM-EDX)     

Xingzhu Ma  Baoku Zhou  Alice Budai  Alhaji Jeng  Xiaoyu Hao  Dan Wei 《Communications in Soil Science and Plant Analysis》2016,47(5):593-601

Biochar is a carbon-rich solid product obtained by pyrolysis of biomass. Here, we investigated multiple biochars produced under slow pyrolysis (235–800 °C), flash carbonization, and hydrothermal carbonization (HTC), using Scanning Electron Microscope—Energy Dispersive X-ray Spectroscopy (SEM-EDX) in order to determine whether SEM-EDX can be used as a proxy to characterize biochars effectively. Morphological analysis showed that feedstock has an integrated structure compared to biochar; more pores were generated, and the size became smaller when the temperature increased. Maximum carbon content (max. C) and average carbon content (avg. C) obtained from SEM-EDX exhibited a positive relationship with pyrolysis temperature, with max. C correlating most closely with dry combustion total carbon content. The SEM-EDX O/C ratios displayed a consistent response with the highest treatment temperature (HTT). The study suggests that SEM-EDX produces highly consistent C, oxygen (O), and C/O ratios that deserve further investigation as an operational tool for characterization of biochar products.  相似文献   

Reduction of porcine reproductive and respiratory syndrome virus (PRRSV) infection in swine alveolar macrophages by porcine circovirus 2 (PCV2)-induced interferon-alpha   总被引：12，自引：0，他引：12  

Chang HW  Jeng CR  Liu JJ  Lin TL  Chang CC  Chia MY  Tsai YC  Pang VF 《Veterinary microbiology》2005,108(3-4):167-177

Two common viral pathogens of swine, namely, porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV), were investigated in regard to their effects on monolayer cultures of swine alveolar macrophages (AMs). The purpose was to identify selected cellular changes and responses potentially associated with the clinical reactions of pigs infected with either or both of these viruses. Measurements included the (1) absolute and relative numbers of infected, viable, and apoptotic cells; (2) distribution of viral antigens; (3) levels of interferon-alpha (IFN-alpha) and tumor necrosis factor-alpha (TNF-alpha) produced and their association with the extent of virus-induced cytopathology. Four groups of AMs were studied, including mock-infected, PCV2 alone-infected (PCV2-A), PRRSV alone-infected (PRRSV-A), and PCV2 and PRRSV dually infected (PCV2/PRRSV) groups. The AMs of PCV2-A group had high antigen-containing rate without cell death. There was a marked increase in cell death and apoptosis in PRRSV-A group. However, a lower PRRSV-induced infectious rate, cell death, and apoptosis were seen in PCV2/PRRSV group. High levels of IFN-alpha production were detected in PCV2-infected groups, but not in mock-infected and PRRSV-A groups. The PRRSV-induced cytopathic effect (CPE) on MARC-145 cells or swine AMs was markedly reduced by pre-incubation of the cells with UV-treated or non-UV-treated supernatants of PCV2-infected AMs. In addition, the reduction in CPE was abolished when the supernatants of PCV2-infected AMs were pre-treated with a mouse anti-recombinant porcine IFN-alpha antibody. The results suggest that swine AMs were an important reservoir of PCV2; PCV2 infection reduced PRRSV infection and PRRSV-associated CPE in PCV2/PRRSV AMs; the reduction of PRRSV infection in AMs was mediated by IFN-alpha generated by PCV2 infection. The reduced PRRSV-associated CPE in AMs and increased pro-inflammatory cytokine production may lead to a more severe pneumonic lesion in those dually infected pigs.  相似文献   

Epithelioid leiomyosarcoma in the visceral peritoneum of an American badger (Taxidea taxus).     

Fun-In Wang  Chih-Hua Chang  Chen-Hsuan Liu  Chian-Ren Jeng 《Journal of veterinary diagnostic investigation》2005,17(1):86-89

A 12-year-old female American badger was presented to the Taipei city zoo veterinary ward with anorexia and weakness. Treatments were ineffective, and the badger died of chronic interstitial nephritis and uremia. At necropsy, numerous firm white nodules, measuring 0.5-2.0 cm, were present on the surface of the liver, stomach, spleen, small intestine, pancreas, and diaphragm. Most nodules were encapsulated and well demarcated from the organs to which they were attached. A poorly demarcated mass, measuring 0.5 cm in diameter, had invaded the hepatic parenchyma and appeared to be the origin of all the nodules derived by transcavitary implantation. Histologically, the nodules contained primarily oval or spindle-shaped cells, typical of smooth muscle cells, forming alternating bundles attached to the surface of the various organs. In some nodules, aggregates of individual polyhedral to round cells with round to oval centrally located nuclei and abundant eosinophilic cytoplasm, typical of smooth muscle origin, were noted. Zones of subcapsular necrosis and multifocal necrosis were also observed in some nodules. Tumor cells stained positively for alpha-smooth muscle actin and vimentin and negatively for desmin, cytokeratin, estrogen, and progesterone receptors. This tumor is similar to but distinguishable from the "disseminated peritoneal leiomyomatosis (DPL)" found in women.  相似文献