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At present a concept prevails that pathological alterations in insect hosts infected with microsporidia, and those associated with hormone imbalance may be explained by the production of juvenile hormone-like (JH) substances by microsporidia. According to another view point, this pathology is a consequence of the host response. We suggested that the microsporidian infection can provoke a stress reaction in insects, which may cause JH secretion by these insects. To confirm this hypothesis, we have analysed major stress protein Hsp70 levels in the infected insects. Using affinity chromatography on ATP-agarose and immunoblotting, we have shown that Hsp70 was accumulated in infected crickets, and that it was the host protein. The consequence of events accompanying the infection in the insects is discussed in relation to the response of hormonal system of the host organism.

Major stress protein HSP72 is known to participate in protecting cells and organisms against harmful factors including ischemia, trauma etc. Under study was the level of HSP72 in the myocardium of 32 patients with coronary disease operated in Military-medical academy. HSP72 was detected in probes of the right atria before and after pre-cardiopulmonary bypass in all cases induction of HSP72 was observed in 40% of patients, and directly correlated with the time of cardiopulmonary bypass and standing of the disease. The cardioprotective effect of the elevated pre-operational level of HSP72 was shown to be proportionate to the lower activity of cardiospecific enzymes, creatine phosphokinase (CK-MB). It is suggested that HSP72 is involved in the mechanism of cardioprotection during cardiopulmonary bypass.

It is known that the essential function of extracellular HSP70 (e-HSP70) to protect cell processes, indirectly associated with the genetic structures. A direct influence of e-HSP70 on chromosomal stability has not been studied. This explains actuality of the suggested investigation. A study was made of the influence of e-HSP70 on chromosomal variability at different phases of the first mitotic cycle in both intact and ciprofloxacin (CF) treated cells of the Indian muntjac skin fibroblasts. E-HSP70 (10 mg/ml) exerts no influence on the level of chromosomal aberrations, typical of the control. After a joint action of e-HSP70 and CF (50 mg/ml) no influence was also exerted on the antibiotic induced genotoxicity effect. CF and e-HSP70 (50 and 100 mg/ml, resp.) acting apart on intact cells during 6 and 24 h induce a significant increase of chromosomal aberrations compared to the control, primarily at the expense of chromatid or chromosomal breaks (depending on the duration of respective effect). CF and e-HSP70 acting apart on intact cells during 6 h with the following cultivation for 18 h in the fresh medium prior to fixation also induce a significant increase of chromosomal aberrations compared to the control, primarily at the expense of both breaks and dicentrics (telomeric associations). The joint action of CF and e-HSP70 on cultivated cells during 6 and 24 h and when CF and e-HSP70 were added respectively on 24 and 6 h prior to fixation, a significant decrease in chromosomal aberrations compared to the control level was induced. A simultaneous addition of CF and e-HSP70 in 6 h with the following cultivation for 18 h in fresh medium prior to fixation exerted no influence on the degree of genotoxicity effect, typical of the separate action of these agents. However a significant decrease in the number of dicentrics occurred. Apparently, e-HSP70 has a protective effect on chromosomal stability mainly at phase 62 of the mitotic cycle. The denaturated e-HSP70 (50, 100 mg/ml) has a genotoxicity effect similar to that of the infact e-HSP70 under above conditions. The joint action of CF and denaturated e-HSP70 (50 mg/ml) during 24 h exerts no influence on the degree of genotoxicity effect, induced by the separate action of these agents or leads to an increase in the number of dicentrics, acting separately or jointly compared to the control. The denaturated e-HSP70 (100 mg/ml) acting jointly with CF for 24 h, increases the degree of genotoxicity effects, induced by separate actions of the agents. Lipopolysacharide (50 mg/ml) exerts no influence on the number of chromosomal aberrations in the control. The sensitivity of individual chromosomes and their regions to agents inducing chromosomal instability is different. The preferential involvement of some chromosomes in dicentric formation was observed. A possible role of dicentrics in adaptation of cells belonging to "markerless" lines to infavourable factors of the environment, and possible mechanisms of protecting effect exerted by e-HSP70 on chromosomes are discussed.