Rocio Zataraín-Palacios’s research while affiliated with University of Colima and other places

Skin secretions of toads are a complex mixture of molecules. The substances secreted comprise more than 80 different compounds that show diverse pharmacological activities. The compounds secreted through skin pores and parotid glands are of particular interest because they help toads to endure in habitats full of pathogenic microbes, i.e., bacteria, fungi, viruses, and protozoa, due to their content of components such as bufadienolides, alkaloids, and antimicrobial peptides. We carried out an extensive literature review of relevant articles published until November 2022 in ACS Publications, Google Scholar, PubMed, and ScienceDirect. It was centered on research addressing the biological characterization of the compounds identified in the species of genera Atelopus, Bufo, Duttaphrynus, Melanophryniscus, Peltopryne, Phrynoidis, Rhaebo, and Rhinella, with antibacterial, antifungal, antiviral, and antiparasitic activities; as well as studies performed with analogous compounds and skin secretions of toads that also showed these activities. This review shows that the compounds in the secretions of toads could be candidates for new drugs to treat infectious diseases or be used to develop new molecules with better properties from existing ones. Some compounds in this review showed activity against microorganisms of medical interest such as Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Coronavirus varieties, HIV, Trypanosoma cruzi, Leishmania chagasi, Plasmodium falciparum, and against different kinds of fungi that affect plants of economic interest.

Carbohydrate metabolism via cyclodextrins (CM-CD) is an uncommon starch-converting pathway that thoroughly depends on extracellular cyclomaltodextrin glucanotransferases (CGTases) to transform the surrounding starch substrate to α-(1,4)-linked oligosaccharides and cyclodextrins (CDs). The CM-CD pathway has emerged as a convenient microbial adaptation to thrive under extreme temperatures, as CDs are functional amphipathic toroids with higher heat-resistant values than linear dextrins. Nevertheless, although the CM-CD pathway has been described in a few mesophilic bacteria and archaea, it remains obscure in extremely thermophilic prokaryotes (T opt ≥ 70 °C). Here, a new monophyletic group of CGTases with an exceptional three-domain ABC architecture was detected by (meta)genome mining of extremely thermophilic Thermoanaerobacterales living in a wide variety of hot starch-poor environments on Earth. Functional studies of a representative member, CldA, showed a maximum activity in a thermoacidophilic range (pH 4.0 and 80 °C) with remarkable product diversification that yielded a mixture of α:β:γ-CDs (34:62:4) from soluble starch, as well as G3-G7 linear dextrins and fermentable sugars as the primary products. Together, comparative genomics and predictive functional analysis, combined with data of the functionally characterized key proteins of the gene clusters encoding CGTases, revealed the CM-CD pathway in Thermoanaerobacterales and showed that it is involved in the synthesis, transportation, degradation, and metabolic assimilation of CDs.

Taurine is an abundant metabolite associated with regulation of cell volume. Several signaling pathways are stimulated at a micromolar concentrations of taurine. However, most of the experimental studies employ this compound at a very high concentration (tens of millimolar). In this study, the role of a chronic treatment with a micromolar dosage of taurine in the physical performance of skeletal muscle of castrated-aged mice was characterized. Taurine was administered in drinking water (800 μM) to 9-months-old castrated (or sham) mice at approximately 20 mg/kg per day for 12 weeks. The weight of the mice, grip strength, food and water intake were monitored. Soleus or EDL muscles were dissected for determinations of force and fatigue. Castrated mice show a slow increase in body mass and a sustained reduction of grip strength. The taurine treatment delays the weigh recovery and generates a decrease in force of castrated and sham mice. No effect of taurine was observed in young mice. The food intake was significantly reduced in castrated mice treated with taurine (with no effect in water intake). The raw force generation or muscle mass in EDL and soleus muscle were similar in treated mice in comparison with control groups. Interestingly, the taurine treatment generated an increased fatigability in both EDL and soleus muscle. We suggest that a submillimolar concentration of taurine chronically administered during aging produce negative effect in physical performance. Caution should be taken when this compound is routinely consumed by old adults.

Diatoms are ubiquitous in all aquatic areas. Recently, these marine microorganisms gained attention because of their health benefits, especially when addressing the problem of antibiotic resistance. In this study, Actinoptychus octonarius Ehrenberg was identified by its ultrastructural details by Scanning Electron Microscopy (SEM). Additionally, the antibacterial properties of A. octonarius Ehrenberg were evaluated employing the method of disk diffusion against Staphylococcus aureus and Vibrio vulnificus bacteria. Four A. octonarius Ehrenberg extracts were obtained by the sequential multi-solvent extraction process using hexane, dichloromethane, methanol, and water. The best antibacterial activity was observed for the methanol extract, which had a significant effect against S. aureus and V. vulnificus. Hexane extracts showed a limited antibacterial activity only against S. aureus and showing no significant effects against V. vulnificus. The area of inhibition of the extracts was higher to 1 cm2. The aqueous and dichloromethane extracts did not present antibacterial activity. In summary, this study revealed, for the first time, morphological characteristics of A.octonarius Ehrenberg diatom through a SEM methodology. Furthermore, it was observed that molecules present in the methanolic extracts of A. octonarius Ehrenberg have antibacterial action against Gram-positive S. aureus and Gram-negative V. vulnificus., while the hexane extract showed effect only against V. vulnificus.