Melanins, pigments of polymer structure, are known to be unique energy transmitters. Being amorphous semiconductors, they are able to absorb and scatter various types of energy. Disturbances in melanin metabolism are involved in the etiology of various disorders, such as Parkinsonism, senile deafness, pigment abnormalies, Vaardenburg's, Usher's and Down's syndromes, Alzheimer disease, etc. Melanins are used in pharmacology and cosmetics as antioxidants, radioprotectors, and medicines against ageing diseases; they are also used for skin and eye protection from UV-irradiation. Melanin photoprotective, immunostimulating and mitogen activities have been actively investigated. Melanins are applied as ingredients of sunscreens. At the same time there are obstacles to apply melanins in practice, because the production of synthetic melanins is expensive; as to natural melanins derived from different sources, their features are various. Most melanins are water-insoluble, which is a serious obstacle for preparation of melanin-containing products.
In 2002-2004 we implemented the ISTC Project A-683. Mutant strains of Bacillus thuringiensis that have high potential to synthesize bacterial melanin (BM) were isolated. The technology for BM production in fermenters and the processes of its isolation from the culture medium and purification from impurities have been developed.
The main physicochemical features of BM were studied; its ecological safety was demonstrated. The produced and purified BM was shown to be an amorphous high-molecular water-soluble polymer. Its cost, according to prior calculation, is dozen times lower than the price of synthetic melanins or pigments prepared from other sources. Investigation of BM features performed in the Project A-683 has revealed its high biological activity. BM was shown to be mighty phytostimulator with hormone-like effect on plant growth and development both in vivo and in vitro. In experiments on laboratory animals with brain surgical trauma BM promoted the recovery of physiological functions and brain tissue regeneration. Preliminary experiments on animal and human cell cultures revealed that BM was not toxic for cells at concentrations many times higher than physiological ones and that cancer cells were more sensitive to the toxic effect of BM in high concentrations than normal cells.
The objectives of this Project will have both fundamental and applied values, developing and enlarging the achievements of the Project A-683. In the course of this project the following tasks are planned: the quality and productivity of melanin strain-producers will be improved; physicochemical, immunological and neuroregenerative properties of the obtained BM will be studied.
The influence of BM on regenerative processes in damaged central and peripheral nervous systems and on the immobilization stress will be investigated. In the frames of this Project the safety of BM will be evaluated and risk assessment will be performed. The main biological effects of BM will be studied (the antioxidant and anticancer activity, the ability to protect cells from UV-irradiation and heat shock, the mitogenic activity, the influence of BM on the organism immune status). As with all studies of new substances, it is necessary to determine the potential danger of BM, i.e. determine the degree of acute, chronic and genetic toxicity in vivo, cyto- and genotoxicity in vitro.
The study of BM as a stimulator of the plant growth and development will be carried out in vivo and in vitro. These investigations will be also conducted in Georgia. BM has several advantages compared with the known growth stimulants – it is easily soluble in water, rapidly degrades in the soil, is effective in very low concentrations, is simple in use. The mentioned features show that the technology for its production is ecologically safe. Moreover, constituents of the medium for theB. thuringiensis strain cultivation are inexpensive and easily available, thus BM production does not require large expenses. This essentially affects the prime cost of BM. Consequently, the increase in production scale will undoubtedly reduce the BM cost.
Proceeding from a prolonged effect of melanin, the other objective of the Project is obtaining of new melaninogenic strains based on the B. thuringiensis strains that have high insecticidal activity. Based on these strains it will be possible to set up a new profitable wasteless manufacture: the biomass obtained at the end of the fermentation will be used as a basis for the insecticide preparation, and BM isolated from culture liquid (CL) - as a biologically active substance.
Among the ecological aims of this project are studies of the influence of melanin and melaninogenic strains on the quality of the soil and its constituents.
The results obtained will promote commercialization of BM preparation as a potential pharmaceutical as well as a phytostimulator for agriculture. Besides, the strain-synthesizing melanin can be used as bioinsecticide.
The proposed Project implementation will exert long-term influence on further investigations of BM. Technologically efficient production of inexpensive water-soluble natural melanin and description of its biological activities will make this valuable product available for common application in pharmacology, cosmetology, agriculture and other areas and ensure future commercial success of this Project. The study of BM effects will open for the Project participants a long-term prospective to develop new active preparations including BM.
The Project proposed fully meets the ISTC goals and promotes them to be realized.
In the process of the Project implementation the participants and collaborators will continuously exchange the information on work progress and the results obtained, etc. The collaborators will comment interim and final reports presented to ISTC, will carry out cross-examination of results and technical examination of participants’ activity. Joint experiments will be performed using collaborators’ equipment. Joint workshops will be periodically organized.
In the process of the Project implementation a number of techniques will be applied: methods of cultivation and testing of animal and plant cells in vitro; study of morphology, functional activity and histochemistry of the nervous system; techniques of genetic engineering and microorganisms biotechnology; methods for determination of the product isolation and purification, study of physicochemical and immunological properties of melanins and determination of their cytotoxicity and genotoxicity in vivo and in vitro; analysis of plant enzyme activity; field investigation of plants; methods for determination of insecticidal activity of melaninogenic strains, etc.
