[Communication of gametes at distance. Chemotaxis and chemokinesis in spermatozoa in mammals]. / Comunicación de gametos a distancia. Quimiotaxis y quimiocinesis del espermatozoide en mamíferos.

The communication to distance is controlled chemically by the egg and the spermatozoa as part of the fertilization process, it has been studied intensily in invertebrate animals with outside fertilization. However studies with mammals offers a field of great interest. The chemoattractant from mammals spermatozoa include peptides or protein with a molecular weight of 1-20 KDa, hormones like progesterone, oxitocin, adrenalin and receptors on the spermatozoa head which are associated with the Guanylyl cyclase enzyme and G proteins, as well as other as like odorant receptor, rhodoopsin kinases and arresting. Chemotaxis allow us to understand the fertilization in human and also develop program for assisted reproduction. It is very important in the contraception.

[Oxygen reactive species in spermatozoa]. / Especies reactivas de oxígeno en el espermatozoide.

The free radicals of oxygen are chemical species of this element formed through enzymatics and non enzymatics reactions and they have been involved in many pathologic and physiologic processes. The most reactive chemical species of oxygen are the hydrogen peroxide and the free radicals frecuradils superoxide anion, hydroxil and free radical, this one being the most reactive. The mammalian spermatozoa, including the human, produce free radicals of oxygen and hydrogen peroxide; although this cell normally has enzymatic mechanics to protect itself from the possible damage of this toxic agents. In spite of, the spermatozoa is susceptible to "oxitative stress", and maybe it is due to the high concentrations of insaturated fatty acids. This fact may be important in the pathology of certain types of masculine infertility like oligozoospermia, because it displays a discontrol production of oxygen reactive species in the spermatozoa.

Screening of antimicrobial activity of plants popularly used in Guatemala for the treatment of dermatomucosal diseases.

Ethnobotanical surveys were conducted among traditional healers and local market vendors; about 200 plants used in Guatemala for the treatment of dermatomucosal diseases were detected. By literature review and according to local availability, 89 plants were selected for in vitro screening for antimicrobial activity against the microorganisms usually causing skin and mucosal infections. Ethanolic macerations were prepared and impregnated in absorbent paper; once dried, these were applied over standardized inocula of Candida albicans, Escherichia, coli, Pseudomonas aeruginosa and Staphylococcus aureus. After incubation, inhibition zones were measured, demonstrating that 28 of the plants exhibited some in vitro inhibition of the tested microorganisms.