Mycoplamas are a group of wall-less prokaryotes widely distributed in nature, some of which are pathogenic for humans and animals. There are many lipoproteins anchored on the outer face of the plasma membrane, called ...Mycoplamas are a group of wall-less prokaryotes widely distributed in nature, some of which are pathogenic for humans and animals. There are many lipoproteins anchored on the outer face of the plasma membrane, called lipid-associated membrane proteins (LAMPs). LAMPs are highly antigenic and could undergo phase and size variation, and are recognized by the innate immune system through Toll-like receptors (TLR) 2 and 6. LAMPs can modulate the immune system, and could induce immune cells apoptosis or death. In addition, they may associate with malignant transformation of host cells and are also con-sidered to be cofactors in the progression of AIDS.展开更多
The henipaviruses,represented by Nipah virus and Hendra virus,are emerging zoonotic viral pathogens responsible for repeated outbreaks associated with high morbidity and mortality in Australia,Southeast Asia,India and...The henipaviruses,represented by Nipah virus and Hendra virus,are emerging zoonotic viral pathogens responsible for repeated outbreaks associated with high morbidity and mortality in Australia,Southeast Asia,India and Bangladesh. These viruses enter host cells via a class I viral fusion mechanism mediated by their attachment and fusion envelope glycoproteins;efficient membrane fusion requires both these glycoproteins in conjunction with specific virus receptors present on susceptible host cells. The henipavirus attachment glycoprotein interacts with a cellular B class ephrin protein receptor triggering conformational alterations leading to the activation of the viral fusion(F) glycoprotein. The analysis of monoclonal antibody(mAb) reactivity with G has revealed measurable alterations in the antigenic structure of the glycoprotein following its binding interaction with receptor. These observations only appear to occur with full-length native G glycoprotein,which is a tetrameric oligomer,and not with soluble forms of G(sG) ,which are disulfide-linked dimers. Single amino acid mutations in a heptad repeat-like structure within the stalk domain of G can disrupt its association with F and subsequent membrane fusion promotion activity. Notably,these mutants of G also appear to confer a post-receptor bound conformation implicating the stalk domain as an important element in the G glycoprotein's structure and functional relationship with F. Together,these observations suggest fusion is dependent on a specific interaction between the F and G glycoproteins of the henipaviruses. Further,receptor binding induces measurable changes in the G glycoprotein that appear to be greatest in respect to the interactions between the pairs of dimers comprising its native tetrameric structure. These receptor-induced conformational changes may be associated with the G glycoprotein's promotion of the fusion activity of F.展开更多
In this study, total mercury in canned tuna in comparison with Hypophthalmichthys molitrix （fitofag or phytophag） fish samples were determined by flow injection cold vapour generation atomic absorption spectrometry ...In this study, total mercury in canned tuna in comparison with Hypophthalmichthys molitrix （fitofag or phytophag） fish samples were determined by flow injection cold vapour generation atomic absorption spectrometry after digestion by the two different methods. The mercury concentration varied from 83 to 290 ng g~ with an average value of 147 ng g-1 in canned tuna, while the concentration varied from 14 to 56 ng g-1 with an average value of 26 ng g-1 for fitofag fish. Recoveries of the total mercury were in the range of 81-107% and 120-160% by method 1 and 2, respectively. The results of this study indicate that tuna and fitofag fish from the Persian Gulf area of Iran have concentrations well below the permissible FAO/WHO levels for total mercury and also the feed regime of fishes can affect the mercury accommodation. Therefore, their contribution to the body burden can be considering negligible and the fish seem to be safe for human consumption.展开更多
Recognition and management of gastrointestinal and hepatic complications of hematopoietic stem cell transplantation has gained increasing importance as indications and techniques of transplantation have expanded in th...Recognition and management of gastrointestinal and hepatic complications of hematopoietic stem cell transplantation has gained increasing importance as indications and techniques of transplantation have expanded in the last few years.The transplant recipient is at risk for several complications including conditioning chemotherapy related toxicities,infections,bleeding,sinusoidal obstruction syndrome,acute and chronic graftversus-host disease(GVHD) as well as other long-term problems.The severity and the incidence of many complications have improved in the past several years as the intensity of conditioning regimens has diminished and better supportive care and GVHD prevention strategies have been implemented.Transplant clinicians,however,continue to be challenged with problems arising from human leukocyte antigen-mismatched and unrelated donor transplants,expanding transplant indications and age-limit.This review describes the most commonly seen transplant related complications,focusing on their pathogenesis,differential diagnosis and management.展开更多
Infectious diseases result from the interactions of host, pathogens, and, in the case of vector-borne diseases, also vec- tors. The interactions involve physiological and ecological mechanisms and they have evolved un...Infectious diseases result from the interactions of host, pathogens, and, in the case of vector-borne diseases, also vec- tors. The interactions involve physiological and ecological mechanisms and they have evolved under a given set of environmental conditions. Environmental change, therefore, will alter host-pathogen-vector interactions and, consequently, the distribution, in- tensity, and dynamics of infectious diseases. Here, we review how climate change may impact infectious diseases of aquatic and terrestrial wildlife. Climate change can have direct impacts on distribution, life cycle, and physiological status of hosts, pathogens and vectors. While a change in either host, pathogen or vector does not necessarily translate into an alteration of the disease, it is the impact of climate change on the interactions between the disease components which is particularly critical for altered disease risks. Finally, climate factors can modulate disease through modifying the ecological networks host-pathogen-vector systems are belonging to, and climate change can combine with other environmental stressors to induce cumulative effects on infectious dis- eases. Overall, the influence of climate change on infectious diseases involves different mechanisms, it can be modulated by phenotypic acclimation and/or genotypic adaptation, it depends on the ecological context of the host-pathogen-vector interactions, and it can be modulated by impacts of other stressors. As a consequence of this complexity, non-linear responses of disease sys- tems under climate change are to be expected. To improve predictions on climate change impacts on infectious disease, we sug- gest that more emphasis should be given to the integration of biomedical and ecological research for studying both the physio- logical and ecological mechanisms which mediate climate change impacts on disease, and to the development of harmonized methods and approaches to obtain more comparable results, as this would support the discrimination of case-specific versus gen- eral mechanisms .展开更多
基金Project (No. 30570093) supported by the National Natural ScienceFoundation of China
文摘Mycoplamas are a group of wall-less prokaryotes widely distributed in nature, some of which are pathogenic for humans and animals. There are many lipoproteins anchored on the outer face of the plasma membrane, called lipid-associated membrane proteins (LAMPs). LAMPs are highly antigenic and could undergo phase and size variation, and are recognized by the innate immune system through Toll-like receptors (TLR) 2 and 6. LAMPs can modulate the immune system, and could induce immune cells apoptosis or death. In addition, they may associate with malignant transformation of host cells and are also con-sidered to be cofactors in the progression of AIDS.
基金supported in part by NIH grant AI054715 to C.C.B.
文摘The henipaviruses,represented by Nipah virus and Hendra virus,are emerging zoonotic viral pathogens responsible for repeated outbreaks associated with high morbidity and mortality in Australia,Southeast Asia,India and Bangladesh. These viruses enter host cells via a class I viral fusion mechanism mediated by their attachment and fusion envelope glycoproteins;efficient membrane fusion requires both these glycoproteins in conjunction with specific virus receptors present on susceptible host cells. The henipavirus attachment glycoprotein interacts with a cellular B class ephrin protein receptor triggering conformational alterations leading to the activation of the viral fusion(F) glycoprotein. The analysis of monoclonal antibody(mAb) reactivity with G has revealed measurable alterations in the antigenic structure of the glycoprotein following its binding interaction with receptor. These observations only appear to occur with full-length native G glycoprotein,which is a tetrameric oligomer,and not with soluble forms of G(sG) ,which are disulfide-linked dimers. Single amino acid mutations in a heptad repeat-like structure within the stalk domain of G can disrupt its association with F and subsequent membrane fusion promotion activity. Notably,these mutants of G also appear to confer a post-receptor bound conformation implicating the stalk domain as an important element in the G glycoprotein's structure and functional relationship with F. Together,these observations suggest fusion is dependent on a specific interaction between the F and G glycoproteins of the henipaviruses. Further,receptor binding induces measurable changes in the G glycoprotein that appear to be greatest in respect to the interactions between the pairs of dimers comprising its native tetrameric structure. These receptor-induced conformational changes may be associated with the G glycoprotein's promotion of the fusion activity of F.
文摘In this study, total mercury in canned tuna in comparison with Hypophthalmichthys molitrix （fitofag or phytophag） fish samples were determined by flow injection cold vapour generation atomic absorption spectrometry after digestion by the two different methods. The mercury concentration varied from 83 to 290 ng g~ with an average value of 147 ng g-1 in canned tuna, while the concentration varied from 14 to 56 ng g-1 with an average value of 26 ng g-1 for fitofag fish. Recoveries of the total mercury were in the range of 81-107% and 120-160% by method 1 and 2, respectively. The results of this study indicate that tuna and fitofag fish from the Persian Gulf area of Iran have concentrations well below the permissible FAO/WHO levels for total mercury and also the feed regime of fishes can affect the mercury accommodation. Therefore, their contribution to the body burden can be considering negligible and the fish seem to be safe for human consumption.
文摘Recognition and management of gastrointestinal and hepatic complications of hematopoietic stem cell transplantation has gained increasing importance as indications and techniques of transplantation have expanded in the last few years.The transplant recipient is at risk for several complications including conditioning chemotherapy related toxicities,infections,bleeding,sinusoidal obstruction syndrome,acute and chronic graftversus-host disease(GVHD) as well as other long-term problems.The severity and the incidence of many complications have improved in the past several years as the intensity of conditioning regimens has diminished and better supportive care and GVHD prevention strategies have been implemented.Transplant clinicians,however,continue to be challenged with problems arising from human leukocyte antigen-mismatched and unrelated donor transplants,expanding transplant indications and age-limit.This review describes the most commonly seen transplant related complications,focusing on their pathogenesis,differential diagnosis and management.
文摘Infectious diseases result from the interactions of host, pathogens, and, in the case of vector-borne diseases, also vec- tors. The interactions involve physiological and ecological mechanisms and they have evolved under a given set of environmental conditions. Environmental change, therefore, will alter host-pathogen-vector interactions and, consequently, the distribution, in- tensity, and dynamics of infectious diseases. Here, we review how climate change may impact infectious diseases of aquatic and terrestrial wildlife. Climate change can have direct impacts on distribution, life cycle, and physiological status of hosts, pathogens and vectors. While a change in either host, pathogen or vector does not necessarily translate into an alteration of the disease, it is the impact of climate change on the interactions between the disease components which is particularly critical for altered disease risks. Finally, climate factors can modulate disease through modifying the ecological networks host-pathogen-vector systems are belonging to, and climate change can combine with other environmental stressors to induce cumulative effects on infectious dis- eases. Overall, the influence of climate change on infectious diseases involves different mechanisms, it can be modulated by phenotypic acclimation and/or genotypic adaptation, it depends on the ecological context of the host-pathogen-vector interactions, and it can be modulated by impacts of other stressors. As a consequence of this complexity, non-linear responses of disease sys- tems under climate change are to be expected. To improve predictions on climate change impacts on infectious disease, we sug- gest that more emphasis should be given to the integration of biomedical and ecological research for studying both the physio- logical and ecological mechanisms which mediate climate change impacts on disease, and to the development of harmonized methods and approaches to obtain more comparable results, as this would support the discrimination of case-specific versus gen- eral mechanisms .
