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681.
Geographic distribution of HBsAg subtypes in Brazil 总被引:1,自引:0,他引:1
HBsAg positive serum samples (896) from five brazilian regions were analysed for HBsAg subtypes. The presence of five different subtypes (ayw2, ayw3, ayw4, adw2 and adw4) was detected. In Northern region subtypes adw4 (41.2%) and adw2 (37.2%) were predominant. In the North East only subtype adw2 was encountered. In Central West, South-East and South, subtypes ayw2, ayw3, adw2 and adw4 were present, with predominance of adw2 in Central West and South East (84.3% and 69.4% respectively) whereas in the South the predominant subtype was ayw3 (41.9%) followed by ayw2 (36.4%). Subtypes ayw1, ayr and adr were not found among the samples studied. These results show the difference in the incidence of HBsAg subtypes in the different regions of Brazil and their significance in relation to the colonization and migrations in this country. 相似文献
682.
Does altered nitrogen metabolism and H2O2 accumulation explain the vitrified status of the fully habituated callus of Beta vulgaris (L.)? 总被引:2,自引:0,他引:2
Frédérik Le Dily Claude Huault Thomas Gaspar Jean-Pierre Billard 《Plant Cell, Tissue and Organ Culture》1993,35(1):69-74
The habituated callus is a vitrified tissue which has two main biochemical characteristics both leading to production of toxic forms of oxygen: first the blockage of the porphyrin pathway and a lack of H2O2 detoxifying enzymes (catalase and peroxidases); secondly a deviation of the nitrogen metabolism induced by NH3 accumulation. Ammonia detoxification is ensured by increased glutamate dehydrogenase activity and accumulation of both proline and polyamines. A putative linkage between proline synthesis and the HMP pathway, as proposed for animal proliferating tissues (Phang 1985), might explain a high purine biosynthesis and cytokinin autonomy.Abbreviations FFA
free fatty acids
- 6PG-DH
6-phosphogluconate dehydrogenase
- G6P-DH
glucose-6-phosphate dehydrogenase
- GLU
glutamate
- GDH
glutamate dehydrogenase
- GR
glutathion reductase
- H
habituated callus
- HMP
hexoses-monophosphate
- IAA
indolyl-acetic acid
- LOX
lipoxygenase
- MDA
malondialdehyde
- N
normal callus
- OAT
ornithine aminotransferase
- ORN
ornithine
- PAs
polyamines
- P5C
pyrroline-5-carboxylate
- P5CR
pyrroline-5-carboxylate reductase
- PP-ribose-P
phosphoribosyl pyrophosphate
- SOD
superoxide dismutase 相似文献
683.
A GC-ECD titration of IAA in normal auxin (2,4-D)-requiring and auxin-independent (habituated) sugarbeet callus revealed an equal amount in both tissues. A comparison of the content and pattern (through starch gel electrophoresis) of soluble, membrane and wall peroxidases indicated that normal tissues contained a higher level of isoperoxidases. Normal tissues also were found to contain higher levels of peroxidase inhibitors and auxin protectors. The hypothesized peroxidase-mediated higher rate of auxin destruction in normal sugarbeet callus is supposed to be counterbalanced by the 2,4-D-controlled auxin protectors. 相似文献