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1.
Research on antifungal proteins and other mechanisms that provide the biochemical basis for host-plant resistance to stalk rot and grain molds is reviewed in this paper. Stalk rot caused by Fusarium species leads to substantial yield loss due to poor grain filling and/or lodging. A transgenic sorghum expressing high levels of chitinase exhibited less stalk rot development when exposed to conidia of F. thapsinum. Grain mold of sorghum is associated with warm humid environments and results from colonization by several fungi (F. thapsinum, Curvularia lunata, and Alternaria alternata) of the developing caryopsis. The roles of several biochemical mechanisms (tannins, phenolic compounds, red pericarp, proteins, hard endosperm, and antifungal proteins) on grain mold resistance are discussed. Resistance mechanisms related to these compounds appear to be additive, and pyramiding of genes is a feasible approach to limit grain deterioration. Several experimental approaches are proposed to extend current findings.  相似文献   
2.
Anaerobic CO dehydrogenases catalyze the reversible oxidation of CO to CO2 at a complex Ni-, Fe-, and S-containing metal center called cluster C. We report crystal structures of CO dehydrogenase II from Carboxydothermus hydrogenoformans in three different states. In a reduced state, exogenous CO2 supplied in solution is bound and reductively activated by cluster C. In the intermediate structure, CO2 acts as a bridging ligand between Ni and the asymmetrically coordinated Fe, where it completes the square-planar coordination of the Ni ion. It replaces a water/hydroxo ligand bound to the Fe ion in the other two states. The structures define the mechanism of CO oxidation and CO2 reduction at the Ni-Fe site of cluster C.  相似文献   
3.
Pasteurella multocida causes various respiratory disease symptoms in pigs, including atrophic rhinitis and pneumonia. In the present study, 69 strains of P. multocida were isolated from 443 pigs with respiratory clinical symptoms at 182 farms located throughout South Korea from 2009 to 2010. A multiplex capsular PCR typing assay revealed that 69 strains of P. multocida isolated in this study had the biosynthetic locus of the capsules of either serogroup A (47 strains, 68.1%) or serogroup D (22 strains, 31.9%). The 22 strains positive for serogroup D-specific primers were divided into four clusters and the 47 strains positive for serogroup A-specific primers were divided into 12 clusters according to the results of Random Amplified Polymorphic DNA (RAPD) analysis. P. multocida strains in the present study were susceptible to most of the antimicrobial agents used. An analysis of antimicrobial resistance and virulence gene pattern combined with RAPD indicated that a certain P. multocida strain appeared to be genetically identical, implying the persistence of the strain within a single farm.  相似文献   
4.
To investigate the potential transmission of subtype H3 influenza virus to cats, a serological survey was carried out in South Korea. Serum samples (n = 1027) were obtained from 809 pet cats and 218 domesticated cats living in urban colonies (D-cats) from 2008 to 2010, and tested using an influenza anti-nucleoprotein (NP)-specific enzyme-linked immunosorbent assay (ELISA) and the haemagglutination inhibition (HI) test, which was recommended by the World Organization for Animal Health. Anti-influenza virus antibodies were detected in 3.12% and 2.43% of cat sera tested using the NP-specific ELISA and HI test, respectively. Anti-H3 antibodies were also identified when the HI assay was used for influenza virus serotyping. These data may indicate the sporadic transmission of subtype H3 influenza virus from other infected species to cats in South Korea.  相似文献   
5.
The expression of myeloperoxidase (MPO) was examined in the swine influenza virus (SIV)-infected neutrophils in the lungs of pigs experimentally infected with swine influenza virus (SIV) subtype H1N2 by immunohistochemistry. Five pigs each from the infected and non-infected group were euthanized 1, 3, 5, 7, and 10?days post-inoculation (dpi). Immunohistochemical reactivity was mainly seen in neutrophils. The score for pulmonary histopathological lesions correlated with the score for MPO immunohistochemical reactivity (r ( s )?=?0.962, P?相似文献   
6.
The effect of three planting dates on stem, stolon, tuber number and size were compared throughout the 1979 and 1980 growing seasons. A relatively warm April and early May and a relatively cool late May and June in 1980 resulted in significantly higher stem and stolon numbers and a tuber population over double that of 1979. The highest average commercial yields ever recorded in the Columbia Basin were obtained with yields in some fields of 100 tons per ha on 48 hectare irrigation circles. On experimental plots tuber numbers increased from the latter part of May with successive sampling dates until late June and early July when a peak in number was reached after which a significant decline in number occurred. The decrease in tuber number was attributed to the phenomenon of reabsorption which was much greater with later planted potatoes. It occurred only in tubers of approximately 10 g size or smaller. Average tuber size in 1980 was one-half that of 1979 although total yield was 25 tons per ha higher because of significantly larger tuber numbers.  相似文献   
7.
Necrotic enteritis (NE) and gangrenous dermatitis (GD) are important infectious diseases of poultry. Although NE and GD share a common pathogen, Clostridium perfringens, they differ in other important aspects such as clinical signs, pathologic symptoms, and age of onset. The primary virulence factors of C perfringens are its four major toxins (alpha, beta, epsilon, iota) and the newly described NE B-like (NetB) toxin. While neutralizing antibodies against some C perfingens toxins are associated with protection against infection in mammals, the serologic responses of NE- and GD-afflicted birds to these toxins have not been evaluated. Therefore, we measured serum antibody levels to C perfringens alpha-toxin and NetB toxin in commercial birds from field outbreaks of NE and GD using recombinant toxin-based enzyme-linked immunosorbent assay (ELISA). Initially, we used this ELISA system to detect antibody titers against C perfringens alpha-toxin and NetB toxin that were increased in birds experimentally coinfected with Eimeria maxima and C perfringens compared with uninfected controls. Next, we applied this ELISA to field serum samples from flock-mated birds with or without clinical signs of NE or GD. The results showed that the levels of antibodies against both toxins were significantly higher in apparently healthy chickens compared to birds with clinical signs of NE or GD, suggesting that these antitoxin antibodies may play a role in protection against NE and GD.  相似文献   
8.
The purpose of this study was to investigate the genetic features of canine coronavirus (CCV) strains detected in Korea. M gene sequences obtained for isolates from 22 dogs with enteritis over a 5-year period were evaluated. Sequence comparison revealed that the 22 Korean CCV strains had an 87.2 to 100% nucleotide homology. Comparing to the typical reference CCV strains (type II), the nucleotide sequence of Korean strains had homology ranged from 86.3% to 98.3% (89.1% to 99.2% for the amino acid sequence) and 87.7% to 97.8% (92.4% to 100% for the amino acid sequence) when compared to FCoV-like CCV strains (type I). Three amino acid variations in the M gene were characteristic for the Korean CCV strains. Phylogenetic analysis demonstrated that the 22 Korean CCV strains belonged to four typical CCV clusters (i.e., a unique Korean CCV cluster, a type II and transmissible gastroenteritis virus cluster, an intermediate cluster between type I and II, and a type I cluster). This study was the first to identify genetic differences of the M gene from Korean CCV strains and provided a platform for molecular identification of different Korean CCV strains.  相似文献   
9.
Clostridium-related poultry diseases such as necrotic enteritis (NE) and gangrenous dermatitis (GD) cause substantial economic losses on a global scale. Two antigenic Clostridium perfringens proteins, elongation factor Tu (EF-Tu) and pyruvate:ferredoxin oxidoreductase (PFO), were identified by reaction with immune sera from commercial meat-type chickens with clinical outbreak of Clostridium infections. In addition to the genes encoding EF-Tu and PFO, C. perfringens alpha-toxin and necrotic enteritis B-like (NetB) toxin were also expressed in Escherichia coli and their corresponding recombinant proteins were purified. Using the four recombinant proteins as target antigens in ELISA immunoassays, high serum antibody titers were observed not only in chickens with clinical signs of Clostridium infections, but also in apparently healthy animals from the same disease-endemic farm. By contrast, no antibodies against any of the proteins were present in the serum of a specific pathogen-free bird. In ELISA using recombinant proteins of C. perfringens, the levels of anti-bacterial protein antibodies were also higher in chickens which were experimentally induced to show NE clinical signs after co-infection with C. perfringens and Eimeria maxima compared with uninfected controls. These results show that two antigenic C. perfringens proteins, EF-Tu and PFO can be useful detection antigens for C. perfringens-afflicted infections in commercial poultry.  相似文献   
10.
A novel peptide nucleic acid (PNA)-based array was developed for use in ante-mortem antigenic typing discrimination in dogs with canine parvovirus (CPV). Cyclic benzothiazole-2-sulfonyl PNA monomers were synthesized that recognized GTA (CPV-2) and TAT (CPV-2a, -2b and -2c) at the nt 913–915 positions, and AAT (CPV-2 and CPV-2a), GAT (CPV-2b), and GAA (CPV-2c) at the nt 1276–1278 positions of the VP2 gene. The detection limits for aa 305 and aa 426 of the VP2 proteins belonging to the four CPV antigenic types were determined optically to be 40–2000 DNA copies, and the optimal cut-off fluorescence signaling value was fixed at 5000. The PNA array described here was developed from 135 field dog fecal specimens and had 89.8% (62/69) sensitivity and 90.4% (66/73) specificity compared with a real-time PCR using the TaqMan assay, a gold standard method. This CPV PNA array could be used together with MGB probe assays as an attractive novel tool for ante-mortem antigenic typing discrimination.  相似文献   
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