Biology subjects

Rosas, C.

Publications and source records attributed to Rosas, C..

8 recordsLinked to original sources

bioRxiv2026

Collagen-based scaffolds loaded with iron oxide nanoparticles promote functional sensorimotor recovery in spinal cord injury

Spinal cord injury disrupts sensorimotor circuits, leading to chronic deficits that require coordinated repair of both spinal and supraspinal circuits. Here, we developed and evaluated a hybrid collagen hydrogel containing chitosan-functionalized iron oxide nanoparticles as a therapeutic scaffold to promote multi-level recovery in a C6 hemisection model in rats. In vitro, both the nanoparticles and the resulting hybrid scaffold show preserved neuronal viability, excitability, and network connectivity. In vivo, scaffold-implanted rats demonstrate significant improvements in gross motor function and postural control, as well as recovery of fine motor skills, forelimb dexterity and grip strength. Sensory evaluations show preserved hindlimb tactile responses accompanied by plasticity within the somatosensory cortex, indicating functional recovery of the different tracts related to sensory and motor functions. At the lesion site, the scaffold enhances neurite outgrowth and modulates the inflammatory milieu, providing a permissive environment for neural repair. These findings indicate that these hybrid collagen scaffolds support relevant integrated structural and functional recovery features after SCI and represent a promising platform for further optimization toward the effective release of therapeutics at the injured spinal cord.

physiology↗

bioRxiv2024

Evaluation of Octopus maya enzyme activity of the digestive gland and gastric juice

BackgroundAs the demand for Octopus maya grows, sustainable farming practices become essential to prevent overexploitation. Thus, its farming development can be a sustainable alternative to traditional fishing. Understanding the digestive dynamics is essential for devising optimal dietary formulations in aquaculture, particularly the role of enzymes like cathepsins and others. Despite the progress in understanding cephalopod digestion, little is known about the specific functioning of the digestive enzymes responsible for breaking down protein substrates. This knowledge gap underscores the need for further research to ensure O. maya population sustainable management. Methods and ResultsDietary formulations are identified for cephalopods by characterizing O. maya digestive enzymes present in the digestive gland and gastric juice. The present investigation revealed that acidic proteases showed a peak activity at higher temperatures than alkaline proteases. Inhibitors confirmed the presence of H, L, and D cathepsins. Noteworthy is a lower activation energy of alkaline enzymes compared to acidic, ones highlighting an intriguing aspect of O. mayas digestive physiology. ConclusionOverall, this research provides valuable insights into O. maya digestive enzyme functions representing a significant advancement in formulating diets crucial for octopus successful farming that may help to fully understand its physiology.

physiology↗

bioRxiv2023

Can upwelling regions be potential thermal refugia for marine species during climate warming? The case of Mexico

Anthropogenic climate warming will change the thermal habitats of marine species worldwide. Species are expected to migrate to higher latitudes as warming intensifies since behavioral and physiological mechanisms have been adapted to maximize fitness under a specific range of temperatures. However, given the possible intensification of upwelling ecosystems, they may act as potential thermal refugia under climate warming, which could protect the diversity of the marine ecosystems, making them important regions for marine resource management. This research aimed to predict the effects of climate warming on commercial and non-commercial marine species (vertebrate and invertebrates) reported in official Mexican documents (> 300 species) based on a thermal niche characterization with the objective to observe if the upwelling regions can act as potential thermal refugia. For this, we considered Representative Concentration Pathway (6.0 and 8.5) scenarios for the present and the future (2040-2050 and 2090-2100). Current and future patterns of suitability, species distribution, richness, and turnover were calculated via ecological niche models using the minimum volume ellipsoids as an algorithm. The results in this study highlight that beyond migration to higher latitudes, some upwelling regions (not all) could be potentially used as some type of "oasis" by marine species refuging from environmental pressure or zones of higher stability of species. Specifically, the upwelling systems in western Baja California and north of Yucatan may be essential regions for future management in Mexico. Nevertheless, it is important to note that climate change acts on numerous ecosystem features, such as trophic relationships, phenology, and other environmental variables not considered here. Future research could test our hypothesis under more realistic simulations. However, migration toward upwelling regions seems to be the most logical selection from all the available ecosystems as climate refugia for marine species beyond movement to higher latitudes or depths.

ecology↗

bioRxiv2022

Specific Ethogram of the Mexican four-eyed octopus: Octopus maya.

Historically, behavior studies have focused mainly on animals of two phyla in particular: Craniata and Arthropoda, however, behavioral research on alternative phyla like mollusks has been increasing because of the potential for research that these models present. When we talk about mollusk behavior, cephalopods are the first group that stands out, however, research on Mexicos endemic species like Octopus maya, is still lacking. This octopus could help to reach a standardized model in neuroscience, because adapts well to laboratory conditions and has been successfully cultured through several generations. These characteristics provide a great advantage as a research model since they could reduce the number of variables that affect behavioral studies, something hard to control with a captured-wild octopus. Hence, in order to work properly with species like this, in research environments, its fundamental to know first the behaviors that this species can perform there. Therefore, the objective of this study was to elaborate an ethogram that describes the behavioral repertoire that O. maya displays in laboratory conditions. Thirteen individuals of O. maya (6-20g) were used and maintained in tanks with a closed circulation seawater system and illuminated with a red light of 30 lx in a 12:12 LD cycle. Nine of these individuals were used for an ad libitum sampling of behaviors to name, define, categorize and operationally describe them. The last four individuals were used to establish day/night activity patterns, (length and frequency of behaviors throughout the day). The obtained results showed that O. maya has a wide behavioral repertoire with at least twenty-three behaviors, which were included in six different behavioral categories. The obtained results showed that O. maya has a wide behavioral repertoire with at least twenty-three behaviors, which were organized in six different behavioral categories. Also, this species showed differentiated activity patterns between day and night, with peaks of activity, distribution, and frequencies of activity behaviors mainly during the light hours. These results showed that O. maya has behaviors comparable with other octopus species and support the proposal for its use as a viable research model. Knowing the behavioral repertoire of O. maya allows for better control in future behavioral studies using this model, provides the main tools to evaluate the organisms health and status, and supports its use for research in neuroscience and cognition.

animal behavior and cognition↗

bioRxiv2022

Trans-generational physiological condition of embryos is conditioned by maternal thermal stress in Octopus maya

Current anthropogenic global warming generates profound metabolic alterations in marine ectotherm invertebrates capable of leading a wide range of these species to extinction. The most worrying and devastating consequence may be that the effect of thermal stress overpasses the individual generations. To evaluate the transgenerational effect of thermal stress on the cephalopod Octopus maya, this study experimentally tests morphology, respiratory metabolism, antioxidant mechanisms, and oxidative stress indicators of the embryos incubated at two temperatures (24 and 30{degrees}C) produced by females acclimated at 24 and 30{degrees}C. The results demonstrate that, regardless of their incubation temperature, embryos from females acclimated at 30{degrees}C are smaller, show more accelerated development, and higher respiratory rates than those from females acclimated at 24{degrees}C. These embryos confirmed a greater oxidative stress degree, as well as an increased amount of soluble carbonylated proteins and catalase activity as the main enzyme during the activation development stage (even the highest in the embryos incubated at 30{degrees}C). Finally, a collapse of the antioxidant defense system was observed, measured as lower both CAT activity and GSH concentrations. Additionally, soluble carbonylated proteins reduced and GST activity increased in embryos incubated at 30{degrees}C from females maintained at high temperatures in a clear deleterious and transgenerational effect of thermal stress on this octopus species.

physiology↗

bioRxiv2021

Constitutive loss of DNMT3A causes morbid obesity through misregulation of adipogenesis

DNA Methyltransferase 3A (DNMT3A) is an important facilitator of differentiation of both embryonic and hematopoietic stem cells. Heterozygous germline mutations in DNMT3A lead to Tatton-Brown-Rahman Syndrome (TBRS), characterized by obesity and excessive height. While DNMT3A is known to impact feeding behavior via the hypothalamus, here we investigated a role in adipocyte progenitors utilizing heterozygous knockout mice that recapitulate cardinal TBRS phenotypes. These mice become morbidly obese due to adipocyte enlargement and tissue expansion. Adipose tissue in these mice exhibited defects in preadipocyte maturation and precocious activation of inflammatory gene networks, including interleukin-6 signaling. Adipocyte progenitor cell lines lacking DNMT3A exhibited aberrant differentiation. Furthermore, mice in which Dnmt3a was specifically ablated in adipocyte progenitors showed enlarged fat depots and increased progenitor numbers, partly recapitulating the TBRS obesity phenotypes. Loss of DNMT3A led to constitutive DNA hypomethylation, such that the DNA methylation landscape of young adipocyte progenitors resemble that of older wild-type mice. Together, our results demonstrate that DNMT3A coordinates both the central and local control of energy storage required to maintain normal weight and prevent inflammatory obesity.

cell biology↗

bioRxiv2018

Sexual maturation and embryonic development in octopus: use of energy and antioxidant defense mechanisms using Octopus mimus as a model.

Sexual maturation and reproduction influence the status of a number of physiological processes and consequently the ecology and behaviour of cephalopods. Using Octopus mimus as model species, the present study examined the changes in biochemical composition that take place during gonadal maturation of octopus females and its consequences in embryo and hatchlings characteristics, including energetic metabolites, digestive enzymes and antioxidant defence mechanisms. A total of 32 Octopus mimus adult females were sampled during ovarian maturation; biochemical composition (metabolites and digestive enzymes) of digestive gland (DG) and ovaries (only metabolites) were followed during physiological and functional maturation. Levels of protein (Prot), triacyl glycerol (TG), cholesterol (Chol), glucose (Glu) and glycogen (Gly) were evaluated. The activity of alkaline and acidic enzymes also was measured in DG. Simultaneously, groups of eggs coming from mature females were sampled along development, and metabolites (Prot, TG, Glu, Gly, TG, Chol), digestive enzymes activity (Lipases, alkaline and acidic), antioxidant defence mechanisms and radical oxygen species (ROS) were evaluated. This study shows that ovarium is a site for reserve of some nutrients for reproduction. Presumably, TG where stored at the beginning of the maturation processes followed by Chol, both at the same time were energetically supported by Glu, derived from Gly following gluconeogenic pathways. Nutrients and enzymes (metabolic, digestive and REDOX system) where maintained without significant changes and in a low activity during organogenesis. Our findings suggest that activity was not energetically costly; in contrast, during the embryo growth there was mobilization of nutrients and activation of the metabolic and digestive enzymes. Increments in consumption of yolk and glycogen, and reduction in molecules associated with oxidative stress allowed paralarvae to hatch with the antioxidant defence mechanisms ready to support ROS production.

physiology↗

bioRxiv2018

Effects of chronic thermal stress on the reproductive performance of male Octopus maya

In female Octopus maya the reproductive success has well-defined thermal limits; beyond which, spawning, number of eggs, fecundity, and the viability of the embryos are reduced. Observations of wild male O. maya suggest that temperatures below 27{degrees}C favour their reproductive performance. From these observations we hypothesize that, as in females, the temperature modulates the reproductive performance of adult O. maya males. The study was directed to evaluate the physiological condition, reproductive success, and histological damage in testis of male O. maya exposed to thermal stress, to determine the implications of ocean warming over their reproductive performance. High temperatures (28-30{degrees}C) negatively affect the growth and health of male O. maya. In octopuses maintained at 30{degrees}C, as a consequence of the thermal stress we observed an increment in the haemocytes number, a reduction in the oxygen consumption rate, and an inflammatory process in the testis. The number of spermatozoa per spermatophore was not affected by temperature, but higher spermatophores production was observed at 30{degrees}C. The paternity analysis showed that the offspring had multiple paternity with an average of 10 males contributing in a single spawn. The paternal contribution was affected by temperature with high, medium, or no paternal contribution in animals maintained at 24{degrees}C (control group), 28{degrees}C, and 30{degrees}C, respectively. The temperatures from 28{degrees}C to 30{degrees}C deeply affected the reproductive performance of Octopus maya males.

ecology↗