Chronic wounds are a major health problem that cause millions of dollars in expenses every year. Among all the treatments used, active wound treatments such as enzymatic treatments represent a cheaper and specific option with a fast growth category in the market. In particular, bacterial and plant proteases have been employed due to their homology to human proteases, which drive the normal wound healing process. However, the use of these proteases has demonstrated results with low reproducibility. Therefore, alternative sources of proteases such as snake venom have been proposed. Here, we performed a functional mining of proteases from rattlesnakes (Crotalus ornatus, C. molossus nigrescens, C. scutulatus, and C. atrox) due to their high protease predominance and similarity to native proteases. To characterize Crotalus spp. Proteases, we performed different protease assays to measure and confirm the presence of metalloproteases and serine proteases, such as the universal protease assay and zymography, using several substrates such as gelatin, casein, hemoglobin, L-TAME, fibrinogen, and fibrin. We found that all our venom extracts degraded casein, gelatin, L-TAME, fibrinogen, and fibrin, but not hemoglobin. Crotalus ornatus and C. m. nigrescens extracts were the most proteolytic venoms among the samples. Particularly, C. ornatus predominantly possessed low molecular weight proteases (P-I metalloproteases). Our results demonstrated the presence of metalloproteases capable of degrading gelatin (a collagen derivative) and fibrin clots, whereas serine proteases were capable of degrading fibrinogen-generating fibrin clots, mimicking thrombin activity. Moreover, we demonstrated that Crotalus spp. are a valuable source of proteases that can aid chronic wound-healing treatments.

Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules. Currently, the effects of the overproduction of methemoglobin derived from snake venom are not extensively recorded. Therefore, the present study aims to describe the oxidative stress induced by Crotalus molossus nigrescens venom using erythrocytes. Human erythrocytes were washed and incubated with different Crotalus molossus nigrescens venom concentrations (0–640 μg/mL). After 24 h, the hemolytic activity was measured followed by attenuated total reflectance-Fourier transform infrared spectroscopy, non-denaturing PAGE, conjugated diene and thiobarbituric acid reactive substances determination. Low concentrations of venom (40 μg/mL). This substance is not degraded by proteases present in the venom. By infrared spectroscopy, starting in 80 μg/mL, we observed changes in bands that are associated with protein damage (1660 and 1540 cm−1) and lipid peroxidation (2960, 2920 and 1740 cm−1). Lipid peroxidation was confirmed by conjugated diene and thiobarbituric acid reactive substance determination, in which differences were observed between the control and erythrocytes treated with venom. Crotalus molossus nigrescens venom provokes hemolysis and oxidative stress, which induces methemoglobin formation, loss of protein structure and lipid peroxidation.

El conocimiento sobre la selección de sitios de anidación en aves rapaces es uno de los factores críticos para realizar cualquier manejo de una población para su conservación. El águila real generalmente elige paredes de roca para anidar, y esta selección está influenciada por las características naturales y antrópicas del paisaje. En México el estudio del águila real es importante debido a que tiene un valor cultural por ser un símbolo patrio y biológico por regular las poblaciones de sus presas, además, se encuentra listada en la Norma Oficial Mexicana 059-SEMARNAT-2010 en la categoría de amenazada y existe escasa información científica publicada sobre su ecología y biología en nuestro país. Por ello, se elaboró un estudio que determinó las variables de hábitat que influyen en los patrones de selección de sitios de anidación del águila real en Janos, Chihuahua. Se buscaron sitios de anidación de águila real y sitios semejantes sin presencia de la especie para tomar los datos de dichas variables; con esta información se analizaron los datos a través de modelos lineales generalizados, tomando como variable de respuesta la presencia y ausencia de nidos y las características del hábitat de los sitios como variables predictoras. Se localizaron 15 sitios de anidación y 16 sitios sin nidos; de 15 variables medidas solo existió diferencia estadística significativa en la altura de las paredes de roca (W = 44.5, p = 0.003001). El modelo con mejor ajuste tuvo un valor de AICc de 20.6, explicando el 68% de la variabilidad de los datos e incluye las variables de altura de las paredes de roca y la rugosidad del terreno, siendo esta última estadísticamente significativa (p =0.0279). La rugosidad del terreno y la altura de la pared de la roca que se presentaron en el mejor modelo reflejando la importancia de la topografía para la selección de sitios de anidación que puede proporcionar aislamiento de perturbaciones para las águilas.

A new species of Dactylopsylla Jordan, parasites of Geomyidae rodents from Chihuahua, is described and illustrated as D. samalayucae n. sp. This species is compared with their morphologically closest relatives. Males are characterized by the shape of the upper lobe of the inmovable and movable process, the shape and chaetotaxy of the distal arm of sternum IX and the shape of the crochet; and females by the contour of the distal margin of sternum VII. The geographical distribution of Dactylopsylla is extended to the Chihuahuan desert in Mexico as D. samalayucae n. sp. is reported from south of the Natural Protected Area Médanos de Samalayuca (MS). A recent key to Dactylopsylla species is updated with inclusion of the new species.

Background: Inland sand dunes are expanding and increasing mobility. Knowledge on the plants growing on them is keystone for their management. One of the largest inland dune systems in Mexico is the Médanos de Samalayuca area. Questions: How many and which species of vascular plants are in Samalayuca? Which is the distribution pattern of that flora? Are there endemisms? Are there species of conservation concern? Studied species: Vascular plants. Study site and dates: Médanos de Samalayuca protected area, northern Chihuahua, Mexico; 2017-2022. Methods: A database was generated based on literature, electronic sources, herbarium specimens, photographing, and collection and identification of materials. Distribution, endemism level and conservation status were recorded. Results: The updated checklist of vascular plants for Samalayuca includes 400 species of 246 genera and 65 families. Most species grow in Mixed desert scrub and in Sand dune vegetation. Almost a half are restricted to the Megamexico 1 region, followed by the North American element. One species is Threatened according to the Mexican Official Norm NOM-059, while two are Vulnerable and one is Almost threatened according to the IUCN. Ribes fontinale appears to be extinct. Conclusions: Considering the arid, extreme climate and the low stability of the psammophilous vegetation, the flora of Samalayuca is richer than expected. The area is home to regional and local endemics. The data and information generated here is baseline for further management programs and action planning to protect these fragile ecosystems and the adjacent communities.