Evaluación de la producción de hormonas esteroides en testículos y ovarios del ratón de las rocas (Peromyscus difficilis felipensis)

En este trabajo se reporta la evaluación de la producción de hormonas esteroides e intermediarios a partir de la biotransformación de colesterol tritiado por las gónadas de machos y hembras del ratón de las rocas -Peromyscus difficilis felipensis-. La síntesis de testosterona fue mayor en los testículos de ratones adultos y menor tanto en los ratones viejos como en los subadultos. En diestro I (metaestro) los ovarios producen más progesterona (P4) que estradiol (E2). Durante el diestro II, la síntesis de P4 tendió a ser menor que la de E2, mientras que en el proestro, esta relación se invirtió. Estos datos constituyen la primera evidencia de la producción in situ de esteroides sexuales en ambos sexos de esta especie de Peromyscus sin haber estado en condiciones previas de laboratorio

Descripción del perfil ontogénico de hormonas esteroides sexuales e intermediarios en testículos del ratón de orejas negras (Peromyscus melanotis, Allen y Chapman, 1897)

Se analizó por radioinmunoanálisis (RIA) el contenido de esteroides sexuales (ES), dos hormonas (progesterona –P4-y testosterona -T-) y tres intermediarios (pregnenolona -P5-; 17a-hidroxi-progesterona –17P4-y androstendiona –A-), en cuatro categorías de edad de Peromyscus melanotis, así como la histología de sus testículos y epidídimos. Cuando se compararon las concentraciones de los ES entre su correspondiente categoría de edad (CE) se encontraron diferencias significativas (P < 0.0001), pero cuando la comparación se hizo entre P5, P4, 17P4 y A en las cuatro CE no hubo diferencias (P > 0.05). Al comparar el contenido de T entre subadultos (CE II) y adultos jóvenes (CE III) la diferencia fue significativa (t1,7 = 30.80, P 0.05); en cambio sí existieron (t1,7 = 14.05, P < 0.0001) cuando la comparación se hizo entre adultos (CE IV) y viejos (CE V). El ciclo ontogénico de la testosterona, así como la espermatogénesis aumentan a partir de la pubertad, alcanzando su máximo en la edad adulta y decrecen progresivamente con el envejecimiento

Cueva del Lazo: Child Sacrifice or Special Funerary Treatment? Discussion of a Late Classic Context from the Zoque Region of Western Chiapas (Mexico)

The text discusses the archaeological remains from Cueva del Lazo (Chiapas, Mexico), a ritual precinct that yielded a group of 11 Late-Terminal Classic children’s partially mummified remains. Uncommon and rich contextual information, mainly derived from the exceptional preservation of perishable materials due to the dry climate of the cave, suggests that the interments could be interpreted as postsacrificial deposits or, alternatively, as funerary contexts whose special character could be linked to the specific sociocultural identity of the buried individuals, all of whom are under six years of age. In order to discuss these possibilities, we describe the archaeological context of the cave as well as review the available archaeological and ethnohistorical information on child sacrifices in Mesoamerica, in order to sketch a meaningful framework useful for interpreting the excavated burials

Global consortium for the classification of fungi and fungus-like taxa

The Global Consortium for the Classification of Fungi and fungus-like taxa is an international initiative of more than 550 mycologists to develop an electronic structure for the classification of these organisms. The members of the Consortium originate from 55 countries/regions worldwide, from a wide range of disciplines, and include senior, mid-career and early-career mycologists and plant pathologists. The Consortium will publish a biannual update of the Outline of Fungi and fungus-like taxa, to act as an international scheme for other scientists. Notes on all newly published taxa at or above the level of species will be prepared and published online on the Outline of Fungi website (https://www.outlineoffungi.org/), and these will be finally published in the biannual edition of the Outline of Fungi and fungus-like taxa. Comments on recent important taxonomic opinions on controversial topics will be included in the biannual outline. For example, 'to promote a more stable taxonomy in Fusarium given the divergences over its generic delimitation', or 'are there too many genera in the Boletales?' and even more importantly, 'what should be done with the tremendously diverse 'dark fungal taxa?' There are undeniable differences in mycologists' perceptions and opinions regarding species classification as well as the establishment of new species. Given the pluralistic nature of fungal taxonomy and its implications for species concepts and the nature of species, this consortium aims to provide a platform to better refine and stabilise fungal classification, taking into consideration views from different parties. In the future, a confidential voting system will be set up to gauge the opinions of all mycologists in the Consortium on important topics. The results of such surveys will be presented to the International Commission on the Taxonomy of Fungi (ICTF) and the Nomenclature Committee for Fungi (NCF) with opinions and percentages of votes for and against. Criticisms based on scientific evidence with regards to nomenclature, classifications, and taxonomic concepts will be welcomed, and any recommendations on specific taxonomic issues will also be encouraged; however, we will encourage professionally and ethically responsible criticisms of others' work. This biannual ongoing project will provide an outlet for advances in various topics of fungal classification, nomenclature, and taxonomic concepts and lead to a community-agreed classification scheme for the fungi and fungus-like taxa. Interested parties should contact the lead author if they would like to be involved in future outlines. </div