Cytokines are released by numerous body tissues to control and coordinate immune responses. However, the role of these molecules in the skeletal muscle has received growing interest. Researchers have demonstrated that contracting skeletal muscle may synthesize and release interleukin-6 (IL-6) and interleukin-15 (IL-15) in response to the exercise. These cytokines potentially have anabolic effects in human skeletal muscle and can be associated with hypertrophic processes.

Clavulanic acid (CA) is a powerful inhibitor of the beta-lactamases, enzymes produced by bacteria resistants to penicillin and cefalosporin. This molecule is produced industrially by strains of Streptomyces clavuligerus in complex media which carbon and nitrogen resources are supplied by inexpensive compounds still providing high productivity. The genetic production improvement using physical and chemical mutagenic agents is an important strategy in programs of industrial production development of bioactive metabolites. However, parental strains are susceptible to loss of their original productivity due genetic instability phenomenona. In this work, some S. clavuligerus mutant strains obtained by treatment with UV light and with MMS are compared with the wild type (Streptomyces clavuligerus ATCC 27064). The results indicated that the random mutations originated some strains with different phenotypes, most divergent demonstrated by the mutants strains named AC116, MMS 150 and MMS 54, that exhibited lack of pigmentation in their mature spores. Also, the strain MMS 150 presented a larger production of CA when cultivated in semi-synthetics media. Using other media, the wild type strain obtained a larger CA production. Besides, using the modifed complex media the MMS 150 strain showed changes in its lipolitic activity and a larger production of CA. The studies also allowed finding the best conditions for a lipase activity exhibited by wild type S. clavuligerus and the MMS150 mutant.

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Exercises involving eccentric actions, mainly in untrained subjects, induce muscular damage to a higher extent than concentric actions. This damage arises from muscle injury and may cause rupture and inflammation of muscle, connective or nervous tissues. These changes in muscle morphology may occur as a direct consequence of exercise-induced mechanical stress or later due to activation of calcium-sensitive degradation pathways and inflammatory response. Later, this damage is exacerbated by the inflammatory response in the days after the exercise. However, an attenuated inflammatory response to a repeated bout reflects in an adaptation to avoid the proliferation of the mechanical disruption of myofibrils. Thus, muscle damage decreases when a person performs the same exercise consistently. This phenomenon is commonly known as the repeated bout effect or protective effect.

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Lipases constitute an important group of biocatalysts for biotechnological applications. This enzyme can be produced by plants, animals, and microorganisms. However, microbial lipases are the most studied and occupy the center attraction because of their stability, selectivity, and broad substrate specificity. Streptomyces are filamentous Gram-positive bacteria found generally in the soil. This microorganism is known mainly for their capacity to synthesize of numerous antibiotics and other secondary metabolites. They also produce a large number of enzymes such as lipases, which makes Streptomyces a genus with significant biotechnological potential.

Cytokines are released by numerous body tissues to control and coordinate immune responses. However, the role of these molecules in the skeletal muscle has received growing interest. Researchers have demonstrated that contracting skeletal muscle may synthesize and release interleukin-6 (IL-6) and interleukin-15 (IL-15) in response to the exercise. These cytokines potentially have anabolic effects in human skeletal muscle and can be associated with hypertrophic processes.