El desierto Chihuahuense. ¿Qué sabemos de el?

En el presente trabajo destaca la importancia del país por su gran biodiversidad, y el número de especies en alguna de las categorías de la NOM-059-ECOL-94. Se describen algunos aspectos abióticos y bióticos del desierto chihuahuense, así como la problemática asociada. Una medida alternativa es la creación de la escuela de biología, que tiene como uno de sus objetivos la formación de recursos humanos en el manejo de recursos naturales. In the following paper there is special attention on the hight biodiversity and the number of species in the NOM-059-ECOL-94 in México. There is a description of some biological and abiotical aspects of the chihuahuan desert, as well as the problems asociated with it. One alternative is the creation of the school of biology, with one of its objetives the formation of human resources in management of natural resources

A comparative analysis of hemolithic activity between Cortalus molossus and Crotalus molossus nigrescens subespecies

Blacktailed rattlesnake (Crotalus molossus) has four subspecies distributed in México; two of them are distributed in Chihuahua. Literature shows that few studies have been done in order to analyze the composition of their venom. Therefore, this study was carried out to evaluate protein content and hemolytic damage by agarose-human erythrocyte substrate between the Crotalus molossus nigrescens and Crotalus molossus molossus subspecies. Mann Whitney’s nonparanteric test was used in order to get the statistics analysis at an IC95. Protein concentration of Crotalus m. nigrescens was 466 ± 35.0 mg mL-1 and Crotalus m. molossus of 449 ± 90.0 mg mL-1 there was no statistical difference detected at IC95 (p>0.05). The protein profile of the venom of Crotalus m. nigrescens showed two protein bands with elevated masses approximately 230 kDa in comparison with Crotalus m. molossus that was of 16 kDa approximately. Crotalus m. nigrescens’s venom was 18 % more hemolytic (156.7±23.33 UHD) than Crotalus m. molossus’s (128±23.32 UHD) at the first hour and 20 % more hemolytic at the second hour, with UHD values of 116.7 ± 12.3 and 94 ± 9.8, respectively. The venom of the two subspecies did not show differences statistically at an IC95 at the first hour (p>0.05) and second hour (p>0.05). It could be concluded that two subspecies samples showed iqual proteomic characteristics. These differences can be attributed to the different eating habits due to the altitude, geographical distribution and the season. It can also be concluded that more investigation regarding venom of rattlesnakes is needed

Thermoregulation in a saxicolous population of the lizard Urosaurus ornatus from the northern Chihuahuan Desert, Mexico

Environmental temperatures often regulate the activity and physiological processes of ectotherms. Because environmental temperatures can vary significantly among seasons, lizards exposed to different thermal conditions in different months could differ in how they thermoregulate or behave. Here, we present a combination of field, laboratory, and modeling approaches to examine thermoregulation, habitat thermal quality, and hours of thermal restriction on activity in a saxicolous population of Urosaurus ornatus in two thermally contrasting months (June and October) in a micro-insular mountain system in the northern Chihuahuan Desert in Mexico. Both active and preferred body temperatures did not vary between months. In this population, U. ornatus is an active thermoregulator with highly accurate and efficient thermoregulation despite the thermal quality in both months. However, during the breeding season (June) activity is restricted (i.e., high number of hours of restriction) compared to the non-breeding season (October). Therefore, our results suggest that this saxicolous population of U. ornatus could be threatened by global climate change and it is essential to determine a conservation strategy for this population

Thermoregulation in a saxicolous population of the lizard Urosaurus ornatus from the northern Chihuahuan Desert, Mexico

Abstract Environmental temperatures often regulate the activity and physiological processes of ectotherms. Because environmental temperatures can vary significantly among seasons, lizards exposed to different thermal conditions in different months could differ in how they thermoregulate or behave. Here, we present a combination of field, laboratory, and modeling approaches to examine thermoregulation, habitat thermal quality, and hours of thermal restriction on activity in a saxicolous population of Urosaurus ornatus in two thermally contrasting months (June and October) in a micro-insular mountain system in the northern Chihuahuan Desert in Mexico. Both active and preferred body temperatures did not vary between months. In this population, U. ornatus is an active thermoregulator with highly accurate and efficient thermoregulation despite the thermal quality in both months. However, during the breeding season (June) activity is restricted (i.e., high number of hours of restriction) compared to the non-breeding season (October). Therefore, our results suggest that this saxicolous population of U. ornatus could be threatened by global climate change and it is essential to determine a conservation strategy for this population.</jats:p

Bioprospection of rattlesnake venom peptide fractions with anti-adipose and anti-insulin resistance activity in vitro

Animal venoms are natural products that have served as a source of novel molecules that have inspired novel drugs for several diseases, including for metabolic diseases such as type-2 diabetes and obesity. From venoms, toxins such as exendin-4 (Heloderma suspectum) and crotamine (Crotalus durissus terrificus) have demonstrated their potential as treatments for obesity. Moreover, other toxins such as Phospholipases A2 and Disintegrins have shown their potential to modulate insulin secretion in vitro. This suggests an unexplored diversity of venom peptides with a potential anti-obesogenic in Mexican rattlesnake venoms. For that reason, this study explored the in vitro effect of Crotalus venom peptide-rich fractions on models for insulin resistance, adipocyte lipid accumulation, antioxidant activity, and inflammation process through nitric oxide production inhibition. Our results demonstrated that the peptide-rich fractions of C. aquilus, C. ravus, and C. scutulatus scutulatus were capable of reverting insulin resistance, enhancing glucose consumption to normal control; C. culminatus, C. molossus oaxacus, and C. polystictus diminished the lipid accumulation on adipocytes by 20%; C. aquilus, C. ravus, and C. s. salvini had the most significant cellular antioxidant activity, having nearly 80% of ROS inhibition. C. aquilus, C. pyrrhus, and C. s. salvini inhibited nitric oxide production by about 85%. We demonstrated the potential of these peptides from Crotalus venoms to develop novel drugs to treat type-2 diabetes and obesity. Moreover, we described for the first time that Crotalus venom peptide fractions have antioxidant and inflammatory properties in vitro models