5,620 research outputs found
Giardiavirus internal ribosome entry site has an apparently unique mechanism of initiating translation.
Giardiavirus (GLV) utilizes an internal ribosome entry site (IRES) for translation initiation in the early branching eukaryote Giardia lamblia. Unlike most of the viral IRESs among higher eukaryotes, which localize primarily within the 5'-untranslated region (UTR), the GLV IRES comprises 253 nts of 5'UTR and the initial 264 nts in the open-reading-frame (ORF). To test if GLV IRES also functions in higher eukaryotic systems, we examined it in rabbit reticulocyte lysate (RRL) and found that it functions much less efficiently than the IRES from the Encephalomyocarditis virus (EMCV) or Cricket paralysis virus (CrPV). In contrast, both EMCV-IRES and CrPV-IRESs were inactive in transfected Giardia cells. Structure-function analysis indicated that only the stem-loop U5 from the 5'UTR and the stem-loop I plus the downstream box (Dbox) from the ORF of GLV IRES are required for limited IRES function in RRL. Edeine, a translation initiation inhibitor, did not significantly affect the function of GLV IRES in either RRL or Giardia, indicating that a pre-initiation complex is not required for GLV IRES-mediated translation initiation. However, the small ribosomal subunit purified from Giardia did not bind to GLV IRES, indicating that additional protein factors may be necessary. A member of the helicase family IBP1 and two known viral IRES binding proteins La autoantigen and SRp20 have been identified in Giardia that bind to GLV IRES in vitro. These three proteins could be involved in facilitating small ribosome recruitment for initiating translation
A Rare Giant Pleural Thymoma in Posterior Mediastinum.
Thymoma is an epithelial neoplasm of the thymus, which commonly lies in the anterior mediastinum. Unusually, thymomas can also be found in other locations. Surgical excision, when feasible, appears to provide good results. We encountered a rare case of a thymoma that developed in the right thoracic cavity, and originating from the pleura in posterior mediastinum. We describe the clinical scenario, investigations, and our management of the patient
The Power of Interfacing Departments in Shaping B2B Customer Satisfaction
Extant research identifies service quality and service encounter perceptions as the key determinants of satisfaction. However, no study in a business-to-business environment has examined the simultaneous effect of these two determinants on overall satisfaction. Hence, we do not know which of these two determinants has a stronger impact on service satisfaction. We investigated this issue by collecting data from shipping managers of several firms in Singapore that used the services of ocean freight shipping companies. Results of path analysis indicate that perceptions of service encounters have a relatively stronger impact compared to service quality. Implications of these results are discussed
Role of antioxidant scavenging enzymes and extracellular polysaccharide in pathogenicity of rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae
The role of antioxidant scavenging enzymes of plant pathogenic bacteria: catalase, ascorbate peroxidase and a virulence factor; extracelluar polysaccharide prodn. in detg. the virulence of Xanthomonas oryzae pv. oryzae (Xoo) isolates and its differential reaction to rice cultivars was studied. A varied level of antioxidant scavenging activity and exopolysaccharide prodn. was obsd. among 34 isolates studied, and most of the Xoo isolates with higher catalase activity also exhibited higher ascorbate peroxidase activity. The max. level of catalase (45 ΞΌM H2O2 min-β1 mg-β1 protein)β, ascorbate peroxidase (29 ΞΌM ascorbate min-β1 mg-β1 proteins) activity and exopolysaccharide prodn. (70 mg) was found in isolate Xoo32 which induced max. lesion length on cultivar 'Jaya' upon clip inoculation in virulence assay. Among the 44 cultivars screened, cultivar 'Jeerigesanna' recorded least bacterial blight disease incidence, with 0.7 cm lesion length. The activity of catalase, ascorbate peroxidase and exopolysaccharide can be employed as bio-βchem. markers in detg. the virulence of Xoo under lab. conditions
Role of antioxidant scavenging enzymes and extracellular polysaccharide in pathogenicity of rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae
In the present work, we studied the role of antioxidant scavenging enzymes of plant pathogenic bacteria:Β catalase, ascorbate peroxidase and a virulence factor; extracelluar polysaccharide production in determining the virulence of Xanthomonas oryzae pv. oryzae (Xoo) isolates and its differential reaction to rice cultivars. A varied level of antioxidant scavenging activity and exopolysaccharide production was observed among 34 isolates studied, and most of the Xoo isolates with higher catalase activity also exhibited higher ascorbate peroxidase activity. The maximum level of catalase (45 Β΅M H2O2 min-1 mg-1 protein), ascorbate peroxidase (29 Β΅M ascorbate min-1 mg-1 proteins) activity and exopolysaccharide production (70 mg) was found in isolate Xoo32 which induced maximum lesion length on cultivar βJayaβ upon clip inoculation in virulence assay. Among the 44 cultivars screened, cultivar βJeerigesannaβ recorded least bacterial blight disease incidence, with 0.7 cm lesion length. The activity of catalase, ascorbate peroxidase and exopolysaccharide can be employed as bio-chemical markers in determining the virulence of Xoo under laboratory conditions.Key words: Paddy, plant pathogenic bacteria, antioxidant scavenging enzymes, exopolysaccharide,Β virulence, bio-chemical markers
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