The evidence supporting the recent hypothesis of a homoploid hybrid origin for the butterfly species Heliconius heurippa is evaluated. Data from selective breeding experiments, mate-choice studies, and a wide variety of DNA markers are reviewed, and an alternative hypothesis for the origin of the species and its close relatives is proposed. A scenario of occasional red wing-pattern mutations in peripheral populations of Heliconius cydno with subsequent adaptive convergence towards sympatric mimicry rings involving H. melpomene and H. erato is offered as an alternative to the HHS hypothesis. Recent twists of this tale are addressed in a postscript.

Significant progress has been made over the past 50 years in the control of schistosomiasis japonica in China. However, recent data suggest that the disease is re-emerging. By the end of 2003, Schistosoma japonicum was still endemic in 110 counties in seven provinces in the southern part of China where the long-term reduction of the disease has been replaced by an increase in the number of people infected and areas infested by the intermediate host snail, i.e. Oncomelania hupensis. Explanations are multifactorial, including the construction of the Three Gorges dam, major flooding events, recovery of the Dongting Lake and the possible impact of climate change. An efficacious vaccine against S. japonicum would represent a significant addition to the current arsenal of control tools, particularly in the framework of an integrated control approach. The vaccine could be targeted either towards the prevention of infection or towards the reduction of parasite fecundity. Although progress in this field has been relatively slow, encouraging results have been obtained in recent years using defined native and recombinantly derived S. japonicum antigens. These findings suggest that development of a safe and efficacious vaccine is feasible. This paper reviews the progress in the development of a vaccine against S. japonicum in China, and includes also data from foreign researchers who are engaged in collaborative work with Chinese scientists.

Triosephosphate isomerase (TPI, EC 5.3.1.1) is an ubiquitously expressed enzyme that catalyses the interconversion of dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate in the energy-generating glycolytic pathway. Inherited defects in the TPI gene are characterised biochemically by markedly reduced TPI enzyme activity in all tissues resulting in metabolic block in glycolysis, with accumulating DHAP particularly in red cells. Clinical TPI deficiency is a rare autosomal recessive multi-system disorder characterised by non-spherocytic haemolytic anaemia, recurrent infections, cardiomyopathy, severe and fatal neuromuscular dysfunctions. Reviews of current literature show that after 30 years since TPI deficiency was first described, the disease still remains without effective therapy. However, several potential therapeutic strategies exist for the treatment of inherited metabolic disorders such as TPI deficiency. Development of an effective therapy for TPI deficiency presents a fascinating and formidable challenge for basic laboratory and clinical research. The major aim of this overview is to discuss the current knowledge of TPI deficiency with special emphasis on research efforts directed towards reversing the metabolic effects of the disorder.

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Recent developments dealing with the age-related alteration of enzymes have been examined. Since the last review of this field, three enzymes have been purified to homogeneity from young and old nematodes (enolase, phosphoglycerate kinase, triosephosphate isomerase) and one from the liver of young and old rats (superoxide dismutase). In all cases except for triosephosphate isomerase, the enzymes from old animals show a reduced catalytic ability compared to those from young animals. In addition, new reports of increases in the amount of altered enzymes in late-passage cells in tissue culture have appeared, though contrary evidence has also been published. The data from these and other papers are compared and discussed. Possible explanations for the alteration of enzymes include error theory, substitution of individual amino acids and conformational change without sequence change. Though final conclusions cannot be made, the evidence favors the latter idea to explain the presence of altered enzymes in old animals.