Estudio de la ultraestructura de la espermatogénesis de Anadara tuberculosa (Sowerbi 1833) (Mollusca: Pelecipoda:Arcidae)

Anadara tuberculosa is a bivalve mollusk of the Arcidae family. This species is found at the Pacific coast, from Laguna de Ballenas (Baja California, Mexico) to Peru. Different types of germ cells have been described at the light microscopic level; however, up to date, no ultrastructural studies of these cells have been performed. The aim of the present work was to determine the main ultrastructural features of the germinal cells, and consequently to contribute on a better taxonomic characterization of different species of the Arcidae family. Spermatogonia were characterized by a large spherical and centrally localized nucleus. Heterochromatin was randomly scattered as dense granules throughout the nucleoplasm. Mitochondria were abundant, and vacuoles were seen dispersed in the cytoplasm. Primary spermatocytes had a more condensed chromatin. The number of mitochondria was lower than in spermatogonia. Secondary spermatocytes had nuclei with chromatin placed peripherically with dense granular projections to the center. Nucleus/cytoplasm ratio was lower as compared to the above mentioned cell types. Spermatids showed two stages of differentiation. At the first stage, chromatin was completely condensed with mitochondria increased in size and migrated to the basal pole of the cell. At the second stage, a centriole was seen localized between the mitochondria and acrosome. Spermatozoids showed a pyramidal acrosome and the centriole was placed intermixed with the typical five mitochondria, specific for this specie. Based in our ultrastructural data, we propose the following for this specie: 1) spermatozoids are of the primitive type 2) centriole is present up from the stage of spermatid and not at earlier stages as reported in other species and 3) five mitochondria with pyramidal acrosome are typical characteristic of this specie.Anadara tuberculosa bivalvo de la familia Arcidae, se distribuye ampliamente en las Costas del Pacífico, desde la Laguna de Ballenas (Baja California), hasta Perú. Las células germinales han sido descritas en microscopia óptica pero no su ultraestructura, por lo que el objetivo de este trabajo es describir las principales diferencias entre dichas células, así como la forma del acrosoma el cual puede contribuir como una característica más para la ubicación taxonómica de las especies de esta familia. Se encontró que las espermatogonias tienen un núcleo grande y esférico en posición central con la presencia de gránulos de heterocromatina esparcidos en el nucleoplasma, el retículo endoplasmático rugoso es escaso y está localizado hacia la periferia del núcleo, las mitocondrias son abundantes, y las vacuolas están dispersas en el citoplasma; en los espermatocitos primarios la heterocromatina está más condensada, las mitocondrias disminuyen en número con respecto a las espermatogonias; los espermatocitos secundarios presentan la heterocromatina distribuida hacia la periferia nuclear con proyecciones hasta el centro del núcleo, la cantidad de citoplasma disminuye con respecto a los tipos celulares anteriores. Las espermátidas presentan dos etapas de diferenciación, en la primera la cromatina esta completamente condensada, las mitocondrias se incrementan en tamaño y migran al polo basal, en la segunda se observa el centríolo localizado entre las mitocondrias y el acrosoma. En los espermatozoides el acrosoma es de forma piramidal y el centríolo se encuentra entre las cinco mitocondrias características para esta especie. Los resultados muestran que 1) Los espermatozoides son de tipo primitivo 2) El centríolo se observa a partir de la fase de espermátida y no en etapas tempranas como en otras especies 3) Se encuentra como característica específica de especie la presencia de cinco mitocondrias y acrosoma de forma piramidal

Flavonoids as a Natural Treatment Against Entamoeba histolytica

Over the past 20 years, gastrointestinal infections in developing countries have been a serious health problem and are the second leading cause of morbidity among all age groups. Among pathogenic protozoans that cause diarrheal disease, the parasite Entamoeba histolytica produces amebic colitis as well as the most frequent extra-intestinal lesion, an amebic liver abscess (ALA). Usually, intestinal amebiasis and ALA are treated with synthetic chemical compounds (iodoquinol, paromomycin, diloxanide furoate, and nitroimidazoles). Metronidazole is the most common treatment for amebiasis. Although the efficacy of nitroimidazoles in killing amebas is known, the potential resistance of E. histolytica to this treatment is a concern. In addition, controversial studies have reported that metronidazole could induce mutagenic effects and cerebral toxicity. Therefore, natural and safe alternative drugs against this parasite are needed. Flavonoids are natural polyphenolic compounds. Flavonoids depend on malonyl-CoA and phenylalanine to be synthesized. Several flavonoids have anti-oxidant and anti-microbial properties. Since the 1990s, several works have focused on the identification and purification of different flavonoids with amebicidal effects, such as, -(-)epicatechin, kaempferol, and quercetin. In this review, we investigated the effects of flavonoids that have potential amebicidal activity and that can be used as complementary and/or specific therapeutic strategies against E. histolytica trophozoites. Interestingly, it was found that these natural compounds can induce morphological changes in the amebas, such as chromatin condensation and cytoskeletal protein re-organization, as well as the upregulation and downregulation of fructose-1,6-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase, and pyruvate:ferredoxin oxidoreductase (enzymes of the glycolytic pathway). Although the specific molecular targets, bioavailability, route of administration, and doses of some of these natural compounds need to be determined, flavonoids represent a very promising and innocuous strategy that should be considered for use against E. histolytica in the era of microbial drug resistance

Myosin 1F Regulates M1-Polarization by Stimulating Intercellular Adhesion in Macrophages

Intestinal macrophages are highly mobile cells with extraordinary plasticity and actively contribute to cytokine-mediated epithelial cell damage. The mechanisms triggering macrophage polarization into a proinflammatory phenotype are unknown. Here, we report that during inflammation macrophages enhance its intercellular adhesion properties in order to acquire a M1-phenotype. Using in vitro and in vivo models we demonstrate that intercellular adhesion is mediated by integrin-αVβ3 and relies in the presence of the unconventional class I myosin 1F (Myo1F). Intercellular adhesion mediated by αVβ3 stimulates M1-like phenotype in macrophages through hyperactivation of STAT1 and STAT3 downstream of ILK/Akt/mTOR signaling. Inhibition of integrin-αVβ3, Akt/mTOR, or lack of Myo1F attenuated the commitment of macrophages into a pro-inflammatory phenotype. In a model of colitis, Myo1F deficiency strongly reduces the secretion of proinflammatory cytokines, decreases epithelial damage, ameliorates disease activity, and enhances tissue repair. Together our findings uncover an unknown role for Myo1F as part of the machinery that regulates intercellular adhesion and polarization in macrophages

Human Amebiasis: Breaking the Paradigm?

For over 30 years it has been established that the Entamoeba histolytica protozoan included two biologically and genetically different species, one with a pathogenic phenotype called E. histolytica and the other with a non-pathogenic phenotype called Entamoeba dispar. Both of these amoebae species can infect humans. E. histolytica has been considered as a potential pathogen that can cause serious damage to the large intestine (colitis, dysentery) and other extraintestinal organs, mainly the liver (amebic liver abscess), whereas E. dispar is a species that interacts with humans in a commensal relationship, causing no symptoms or any tissue damage. This paradigm, however, should be reconsidered or re-evaluated. In the present work, we report the detection and genotyping of E. dispar sequences of DNA obtained from patients with amebic liver abscesses, including the genotyping of an isolate obtained from a Brazilian patient with a clinical diagnosis of intestinal amebiasis that was previously characterized as an E. dispar species. The genetic diversity and phylogenetic analysis performed by our group has shown the existence of several different genotypes of E. dispar that can be associated to, or be potentiality responsible for intestinal or liver tissue damage, similar to that observed with E. histolytica

Retos actuales de la farmacia

Retos actuales de la farmacia es un proyecto que está coordinado por Leobargo Manuel Gómez Oliván y un equipo de investigadores que forman parte del claustro de la Facultad de Química en el área de posgrado, ellos han incentivado el espíritu investigador y científico de los estudiantes adscritos al programa para adentrarse en el ámbito farmacéutico. Los capítulos que conforman esta edición son el reflejo de la actividad académica desarrollada en este posgrado en las diferentes áreas de acentuación que lo conforman: farmacia molecular, farmacia social y tecnología farmacéutica

Iron-Binding Protein Degradation by Cysteine Proteases of Naegleria fowleri

Naegleria fowleri causes acute and fulminant primary amoebic meningoencephalitis. This microorganism invades its host by penetrating the olfactory mucosa and then traveling up the mesaxonal spaces and crossing the cribriform plate; finally, the trophozoites invade the olfactory bulbs. During its invasion, the protozoan obtains nutrients such as proteins, lipids, carbohydrates, and cationic ions (e.g., iron, calcium, and sodium) from the host. However, the mechanism by which these ions are obtained, particularly iron, is poorly understood. In the present study, we evaluated the ability of N. fowleri to degrade iron-binding proteins, including hololactoferrin, transferrin, ferritin, and hemoglobin. Zymography assays were performed for each substrate under physiological conditions (pH 7 at 37°C) employing conditioned medium (CM) and total crude extracts (TCEs) of N. fowleri. Different degradation patterns with CM were observed for hololactoferrin, transferrin, and hemoglobin; however, CM did not cause ferritin degradation. In contrast, the TCEs degraded only hololactoferrin and transferrin. Inhibition assays revealed that cysteine proteases were involved in this process. Based on these results, we suggest that CM and TCEs of N. fowleri degrade iron-binding proteins by employing cysteine proteases, which enables the parasite to obtain iron to survive while invading the central nervous system

Dataset of cathepsin L-like CP inhibition of Naegleria fowleri and Acanthamoeba castellanii by ppTvCP4r from Trichomonas vaginalis

The recombinant TvCP4 prepro region (ppTvCP4r) acts as an exogenous inhibitor of cathepsin L-like CPs from Trichomonas vaginalis (Cárdenas-Guerra et al., 2015 [1]). Here, we present the dataset of the trichomonad ppTvCP4r inhibitory effect against the CP proteolytic activities from other microorganisms, such as Naegleria fowleri and Acanthamoeba castellanii free-living amoeba. The proteolytic activity inhibition of total crude extracts (TCEs) of N. fowleri and A. castellanii was determined and recorded using a fluorogenic substrate specific for cathepsin L CPs without or with a ppTvCP4r treatment at different concentrations and pH. Keywords: Acanthamoeba castellanii, Cathepsin L-like CPs, Cysteine proteinase inhibitors, Naegleria fowleri, ppTvCP4r, Trichomonas vaginali