A series of mass mortalities of the cultured blood clam, Tegillarca granosa, occurred in the Yueqing Bay of China from 2005 to 2009. An obligate intracellular prokaryote, designated as rickettsia-like organism （RLO）...A series of mass mortalities of the cultured blood clam, Tegillarca granosa, occurred in the Yueqing Bay of China from 2005 to 2009. An obligate intracellular prokaryote, designated as rickettsia-like organism （RLO）, was frequently found in the moribund or dead blood clam sample during ultra- structural examination. These organisms were usually round, ellipsoid or occasionally dumbbell- shaped, ranged from approximately 0.28 to 0.71 #m in size and had a trilaminar cell wall. Two reproductive modes of organisms, transverse binary fission and budding, were observed. The or- ganisms were able to form eosinophilic inclusions. Most inclusions were found within epithelial and connective tissues of the mantle, gills and digestive tube. The biological and morphological char- acteristics indicate that these organisms may belong to the family Rickettsiaceae. RLOs exhibited significant pathogenicity. Cytopathological examinations revealed extensive necrosis and destruc- tion in the infected cell. The degree of tissue destruction was positively related to the number of RLO inclusions in the tissues, and the cytopathological effects were positively related to the number of intracellular RLO. RLOs and their inclusions were discovered throughout different disease areas and in different time periods. The infection intensity of the RLOs was positively correlated with the mortality rate of clams. Therefore, RLO infection might be associated with mass mortalities of cultured blood clams in the Yueqing Bay.展开更多
The purpose of this project is to reach more students in food, agricultural, and environmental sciences with a globalized undergraduate curriculum, by providing contextually-rich reusable learning objects （RLOs） and...The purpose of this project is to reach more students in food, agricultural, and environmental sciences with a globalized undergraduate curriculum, by providing contextually-rich reusable learning objects （RLOs） and authentic case studies that address multidisciplinary issues. Reusable learning objects （RLOs） are self--contained, digital learning activities that range in length from 2 to 15 minutes. RLOs can contain a wide array of media, including text, web sites, charts, maps, models, PowerPoint presentations, photos, case studies, simulations, video clips, audio clips, and assessments, Food and agricultural sciences faculty at the University of Florida, the University of Georgia, and Texas A＆M University have been selected to be part of a Faculty Learning Community that Will work together in curriculum and RLO development, and will participate in an international study experience funded by this project. For each experience, a group of approximately ten faculty and three project team members will spend roughly two weeks in a Latin American/Caribbean basin country. Various social science data collection processes and evaluation strategies will be the focus of the presentation. The use of preflective and reflective instruments to measure initial attitudes or beliefs about the context-rich multidisciplinary experience and expected gains from participating in the curricula development will be demonstrated.展开更多
基金Scientific Projects of Zhejiang Province,China under contract Nos 2004C23041 and 20080123
文摘A series of mass mortalities of the cultured blood clam, Tegillarca granosa, occurred in the Yueqing Bay of China from 2005 to 2009. An obligate intracellular prokaryote, designated as rickettsia-like organism （RLO）, was frequently found in the moribund or dead blood clam sample during ultra- structural examination. These organisms were usually round, ellipsoid or occasionally dumbbell- shaped, ranged from approximately 0.28 to 0.71 #m in size and had a trilaminar cell wall. Two reproductive modes of organisms, transverse binary fission and budding, were observed. The or- ganisms were able to form eosinophilic inclusions. Most inclusions were found within epithelial and connective tissues of the mantle, gills and digestive tube. The biological and morphological char- acteristics indicate that these organisms may belong to the family Rickettsiaceae. RLOs exhibited significant pathogenicity. Cytopathological examinations revealed extensive necrosis and destruc- tion in the infected cell. The degree of tissue destruction was positively related to the number of RLO inclusions in the tissues, and the cytopathological effects were positively related to the number of intracellular RLO. RLOs and their inclusions were discovered throughout different disease areas and in different time periods. The infection intensity of the RLOs was positively correlated with the mortality rate of clams. Therefore, RLO infection might be associated with mass mortalities of cultured blood clams in the Yueqing Bay.
文摘The purpose of this project is to reach more students in food, agricultural, and environmental sciences with a globalized undergraduate curriculum, by providing contextually-rich reusable learning objects （RLOs） and authentic case studies that address multidisciplinary issues. Reusable learning objects （RLOs） are self--contained, digital learning activities that range in length from 2 to 15 minutes. RLOs can contain a wide array of media, including text, web sites, charts, maps, models, PowerPoint presentations, photos, case studies, simulations, video clips, audio clips, and assessments, Food and agricultural sciences faculty at the University of Florida, the University of Georgia, and Texas A＆M University have been selected to be part of a Faculty Learning Community that Will work together in curriculum and RLO development, and will participate in an international study experience funded by this project. For each experience, a group of approximately ten faculty and three project team members will spend roughly two weeks in a Latin American/Caribbean basin country. Various social science data collection processes and evaluation strategies will be the focus of the presentation. The use of preflective and reflective instruments to measure initial attitudes or beliefs about the context-rich multidisciplinary experience and expected gains from participating in the curricula development will be demonstrated.
