Existence Of Adaptive Response Research Articles

Relieved residual damage in the hematopoietic system of mice rescued by radiation-induced adaptive response (Yonezawa Effect)

Existence of adaptive response (AR) was previously demonstrated in C57BL/6J mice. Irradiations were performed by delivering a priming low dose of X-rays (0.50 Gy) in combination with a challenge high dose of accelerated carbon or neon ion particles. AR was characterized by significantly decreased mortality in the 30-day survival test. This mouse AR model (‘Yonezawa Effect’) was originally established by using X-rays as both the priming and challenge irradiations. The underlying mechanism was due to radio-resistance occurring in blood-forming tissues. In this study, we verified the existence of AR and further investigated residual damage in the hematopoietic system in surviving animals. Results showed that the priming low dose of X-rays could relieve the detrimental effects on the hematopoietic system. We observed both an improvement in the blood platelet count and the ratio of polychromatic erythrocytes (PCEs) to the sum of PCEs and normochromatic erythrocytes (NCEs) and a marked reduction of the incidences of micronucleated PCEs and micronucleated NCEs. These findings suggest that the priming low dose of low linear energy transfer (LET) X-rays induced a protective effect on the hematopoietic system, which may play an important role in both rescue from acute lethal damage (mouse killing) and prevention of late detrimental consequences (residual anhematopoiesis and delayed genotoxic effects) caused by exposure to a high challenge dose from low-LET (X-ray) or high-LET (carbon and neon ion) irradiations. These findings provide new knowledge of the characterization of the Yonezawa Effect by providing new insight into the mechanistic study of AR in vivo.

Significance of adaptive response to study of traditional Chinese medicine

Adaptive response is a topic of general interest in medical research. Utilization of adaptive response has become a new treatment strategy for some diseases, the core of which is to stimulate the mechanisms of body internal protection, to improve the adaptive and anti-injury capability, and to maintain the homeostasis of the body. The existence of adaptive response indicates that the body internal protection can be induced and its key mechanism is the inducement of internal protective factors (internal protective proteins). In this article, some connections between adaptive response and the theory of traditional Chinese medicine (TCM) were discussed, which indicated that adaptive response is much beneficial for explaining some theories of TCM such as correspondence between human and nature, strengthening healthy qi to consolidate constitution, acupuncture theory, adaptogen herbs, and treating disease before its onset, etc. Thus the adaptive response is of great significance for explaining scientifically the connotative meaning of the theories of TCM and for promoting the integration of TCM and western medicine.

Widespread adaptive response against environmental methylating agents in microorganisms

Many bacteriol species have adaptive responses which protect against the toxicity and mutagenicity of methylating agents. Induced 3-methyladenine-DNA glycosylase and O6-methylguanine-DNA methyl-transferase activities increase the cellular capacity of E. coli, B. subtilis, and M. luteus to repair toxic and mutagenic methylated base derivatives in DNA. The DNA methyltransferase or Ada protein of E. coli regulates the response and is converted into a strong transcriptional activator by self-methylation on repair of a methylphosphotriester in DNA. The multiple functions of the E. coli Ada protein (39 kDa) are split between two proteins, AdaA (24 kDa) and AdaB (20 kDa), in B. subtilis. Proteins (39 kDa) recognised by anti-Ada antibodies are efficiently induced in several enterobacteriol species and correlate with increased DNA methyltransferase activities. In contrast, an “Ada-related” protein is only weakly induced in Salmonella typhimurium and no increase in DNA repair activity is detectable.The existence of adaptive responses in diverged bacterial species suggests the frequent occurrence of methylating agents in the environment. Several direct-acting methylating agents which are known to arise in the environment have been shown to induce the response. These include abundantly occurring methyl chloride, the antibiotic streptozotocin,the precursors of the known labile inducers N-methyl-N′-nitrosourea and N-methyl-N′-nitro-N-nitrosoguandine and as shown in this paper, methyl radicals which may arise by the irradiation or oxidation of methyl compounds.