Methionine oxidation to methionine sulfoxide （MetSO） is reversed by two types of methionine sulfoxide reducrases （MSRs）, A and B, specific to the S- and R-diastereomers of MetSO, respectively. MSR genes are found ...Methionine oxidation to methionine sulfoxide （MetSO） is reversed by two types of methionine sulfoxide reducrases （MSRs）, A and B, specific to the S- and R-diastereomers of MetSO, respectively. MSR genes are found in most organisms from bacteria to human. In the current review, we first compare the organization of the MSR gene families in photosynthetic organisms from cyanobacteria to higher plants. The analysis reveals that MSRs constitute complex families in higher plants, bryophytes, and algae compared to cyanobacteria and all non-photosynthetic organisms. We also perform a classification, based on gene number and structure, position of redox-active cysteines and predicted sub-cellular localization. The various catalytic mechanisms and potential physiological electron donors involved in the regeneration of MSR activity are then de- scribed. Data available from higher plants reveal that MSRs fulfill an essential physiological function during environmental constraints through a role in protein repair and in protection against oxidative damage. Taking into consideration the ex- pression patterns of MSR genes in plants and the known roles of these genes in non-photosynthetic cells, other functions of MSRs are discussed during specific developmental stages and ageing in photosynthetic organisms.展开更多
Environmental climate conditions could lead to an increasing global occurrence of microorganism blooms that synthesize toxins in the aquatic environments.These blooms could result in significantly toxic events.Respons...Environmental climate conditions could lead to an increasing global occurrence of microorganism blooms that synthesize toxins in the aquatic environments.These blooms could result in significantly toxic events.Responses of photosynthetic organisms to adverse environmental conditions implicate reactive oxygen species generation;but,due to the presence of a varied cellular antioxidant defense system and complex signaling networks,this oxidative stress could act as an important factor in the environmental adaptive processes.The objective of this review was to assess how some biotoxins are implicated in the generation of oxidative and nitrosative metabolic changes,not only in biotoxin-producing organisms but also in non-producing organisms.Therefore,toxins may modify the oxidative cellular balance of several other species.Hence,the effect of toxins on the oxidative and nitrosative conditions will be evaluated in freshwater and marine algae and vascular plants.The changing climate conditions could act as agents capable of modifying the community composition leading to alterations in the global health of the habitat,risking the survival of many species with ecological relevance.展开更多
基金supported by the National Natu-ral Sciences Foundation of China (40771005 30870382)+1 种基金the CAS (Chinese Academy of Sciences) Action Plan for West Development Project (KZCX2-XB2-04-01KZCX2-XB2-09-03)
文摘Methionine oxidation to methionine sulfoxide （MetSO） is reversed by two types of methionine sulfoxide reducrases （MSRs）, A and B, specific to the S- and R-diastereomers of MetSO, respectively. MSR genes are found in most organisms from bacteria to human. In the current review, we first compare the organization of the MSR gene families in photosynthetic organisms from cyanobacteria to higher plants. The analysis reveals that MSRs constitute complex families in higher plants, bryophytes, and algae compared to cyanobacteria and all non-photosynthetic organisms. We also perform a classification, based on gene number and structure, position of redox-active cysteines and predicted sub-cellular localization. The various catalytic mechanisms and potential physiological electron donors involved in the regeneration of MSR activity are then de- scribed. Data available from higher plants reveal that MSRs fulfill an essential physiological function during environmental constraints through a role in protein repair and in protection against oxidative damage. Taking into consideration the ex- pression patterns of MSR genes in plants and the known roles of these genes in non-photosynthetic cells, other functions of MSRs are discussed during specific developmental stages and ageing in photosynthetic organisms.
基金supported by grants from the University of Buenos Aires(UBACyT,20020170100199BA)the National Council for Science and Technology(CONICET,PIP 11220170100539CO).
文摘Environmental climate conditions could lead to an increasing global occurrence of microorganism blooms that synthesize toxins in the aquatic environments.These blooms could result in significantly toxic events.Responses of photosynthetic organisms to adverse environmental conditions implicate reactive oxygen species generation;but,due to the presence of a varied cellular antioxidant defense system and complex signaling networks,this oxidative stress could act as an important factor in the environmental adaptive processes.The objective of this review was to assess how some biotoxins are implicated in the generation of oxidative and nitrosative metabolic changes,not only in biotoxin-producing organisms but also in non-producing organisms.Therefore,toxins may modify the oxidative cellular balance of several other species.Hence,the effect of toxins on the oxidative and nitrosative conditions will be evaluated in freshwater and marine algae and vascular plants.The changing climate conditions could act as agents capable of modifying the community composition leading to alterations in the global health of the habitat,risking the survival of many species with ecological relevance.
