Inhibition of post-mortem fish muscle softening and degradation using legume seed proteinase inhibitors

Inhibitors that control muscle softening are important for regulating the activities of specific proteinases in meat. Proteolytic activity of endogenous proteinases in postmortem fish leads to the deterioration of myofibres. Calpain proteolytic enzyme system in skeletal muscles is mainly responsible for the post-mortem proteolysis. Soluble sarcoplasmic serine proteinase and the insoluble myofibrillar serine proteinase fractions contribute to the modori effects in surimi gels while myosin heavy chains contribute to gel strength. Proteolytic degenerative processes negatively affect the entire quality spectrum of the fish as food. Legume seeds are a good source of proteinase inhibitors with the potential to emerge as a promising tool in fish meat quality management. Many workers have studied the potent inhibitory effect of the seed flour from various legume crops on the flesh, surimi gels and visceral proteinases of fishes. The present review provides collective information about proteolysis in fish and its control by using legume seed flour as a natural source of proteinase inhibitors. Use of legume seed flour can reduce the dependence of the meat processing industry on the non-renewable synthetic chemical agents. Moreover, the use of natural products from sustainable resources also leads to the improved economics of meat production.

HIV aspartyl protease inhibitors as promising compounds against Candida albicans André Luis Souza dos Santos

Cells of Candida albicans (C. albicans) can invade humans and may lead to mucosal and skin infections or to deep-seated mycoses of almost all inner organs, especially in immunocompromised patients. In this context, both the host immune status and the ability of C. albicans to modulate the expression of its virulence factors are relevant aspects that drive the candidal susceptibility or resistance; in this last case, culminating in the establishment of successful infection known as candidiasis. C. albicans possesses a potent armamentarium consisting of several virulence molecules that help the fungal cells to escape of the host immune responses. There is no doubt that the secretion of aspartyl-type proteases, designated as Saps, are one of the major virulence attributes produced by C. albicans cells, since these hydrolytic enzymes participate in a wide range of fungal physiological processes as well as in different facets of the fungal-host interactions. For these reasons, Saps clearly hold promise as new potential drug targets. Corroborating this hypothesis, the introduction of new anti-human immunodeficiency virus drugs of the aspartyl protease inhibitor-type (HIV PIs) have emerged as new agents for the inhibition of Saps. The introduction of HIV PIs has revolutionized the treatment of HIV disease, reducing opportunistic infections, especially candidiasis. The attenuation of candidal infections in HIV-infected individuals might not solely have resulted from improved immunological status, but also as a result of direct inhibition of C. albicans Saps. In this article, we review updates on the beneficial effects of HIV PIs against the human fungal pathogen C. albicans, focusing on the effects of these compounds on Sap activity, growth behavior, morphological architecture, cellular differentiation, fungal adhesion to animal cells and abiotic materials, modulation of virulence factors, experimental candidiasis infection, and their synergistic actions with classical antifungal agents.