Autonomous University of Tlaxcala

Background Understanding the diversity and distribution of fungal communities at a regional scale is important since fungi play a crucial role in ecosystem functioning. Our study used environmental metagenomics to determine fungal communities in mountainous forest soils in the central highlands of Mexico. Methods We used four different bioinformatic workflows to profile fungal assemblages, i.e ., Geneious+UNITE, single- and paired-end microbial community profiling (MiCoP), and Kraken2. Results The workflows yielded different results; one detected a higher abundance of ectomycorrhizal (EcM) and saprophytic fungi, while the other identified more saprophytic and pathogenic fungi. Environmental, vegetation, and geographical factors determined the spatial distribution of soil fungi at a regional scale. Potential hydrogen (pH), calcium (Ca), magnesium (Mg), and silt content were detected as common drivers of fungal communities across different datasets enriched towards a functional guild. Vegetation traits were found to be more influential in shaping symbiotrophic fungi composition than saprotrophic and pathogenic fungi. This highlights the importance of considering vegetation traits when studying fungal community diversity and distribution. Clustering patterns of sampling points near the volcanoes indicated shared environmental and vegetation characteristics. A weak but significant distance decay in taxonomic similarity revealed that dispersal limitation contributed to fungal community composition, although it was not the primary factor in this study. Overall, this study provides important insights into the challenges and opportunities of studying fungal communities at a regional scale using metagenomic data.

Foraging during breeding is a demanding activity linked to breeding investment and possibly constrained by individual quality. Telomere length, the protective nucleoproteins located at the ends of the chromosomes, is considered a trait reflecting somatic maintenance and individual quality. Therefore, foraging effort and parental investment may be positively related to telomere length, if individuals with longer telomeres are of better quality and thus able to maintain better body condition and allocate more resources to parental activities. In the brown booby (Sula leucogaster), we investigated if telomere length is related to body mass (a proxy of condition) and whether variation in foraging behavior and provisioning effort is related to telomere length or body mass. Then, we explored whether variation in foraging and provisioning influences the chick mass growth rate. In 34 pairs nesting in Isla de San Jorge, in the Gulf of California, México, we sampled their blood to estimate telomere length, measured their body mass, and for 10 days, recorded their foraging behavior via global positioning system (GPS) loggers and their chick provisioning rate and chicks' mass growth rate. We found a positive relationship between parents' body mass and telomere length. Body mass did not affect foraging behavior. Females with longer telomeres were more prone to travel longer distances toward offshore and deeper waters than females with shorter telomeres. In contrast, males with longer telomere lengths performed more nearshore foraging trips than males with shorter telomeres. The chick provisioning rate was unrelated to telomere length or body mass, but females fed the chick at a rate 2.4 times greater than males. Females' offshore foraging, but not males', was positively related to chick mass growth rate. Our results suggest that individual quality, indicated by telomere length, is an important driver of sex‐specific, between‐individual variation in foraging behavior, indirectly affecting offspring condition.

At the intraspecific level, most bat species exhibit variations in body condition. Since body condition reflects the animals’ energy reserves, as fat, and lean mass, and the size of organs, it would be positively related to the velocity at which they process energy. We measured the basal metabolic rate under laboratory conditions in Eptesicus fuscus (n= 27) (differing in body mass between 11.2 to 17.6 g), and Lasiurus cinereus (n=18) (differing in body mass between 17.7 to 25.6 g), using open-flow respirometry, living in central Mexico. We estimated the relationship between basal metabolic rate and body condition (measured as body mass) using simple linear models. In both bat species, we found a positive relationship between these traits. Our result is likely explained by variations in metabolic active tissue and fat reserves. These differences may play a key role in natural selection of bats, affecting their energy processing and allocation strategies across different energy-spending ecological scenarios.

In this study, we evaluated the effects of intrabursal administration of cabergoline and N-acetylcysteine on ovarian hyperstimulation syndrome (OHSS) in an immature rat model. The study assessed body, ovarian, and uterine weights, as well as the concentrations of vascular endothelial growth factor A (VEGF-A). Moreover, levels of MDA, 4-HDA, and nitrites were assessed in ovarian homogenates, and vascular permeability was quantified in the peritoneal cavity. Ovarian morphology was characterized using histology and hematoxylin–eosin staining, determining the count of ovarian follicles and corpus luteum. Our results demonstrated a significant increase in lipoperoxidation, nitrite levels, and VEGF-A concentrations in the OHSS group compared to the control group. These biochemical alterations corroborate the successful induction of OHSS in the experimental model. Direct injection into the ovarian bursa resulted in reduced vascular permeability and VEGF-A levels, suggesting that the effects of cabergoline are predominantly ovarian. Particularly, cabergoline did not significantly alter other parameters such as ovarian weight, lipoperoxidation, nitrite levels, or morphology. Conversely, low concentrations of N-acetylcysteine (25–50 µg/kg) significantly reduced ovarian and uterine weights, VEGF-A levels, and vascular permeability. Interestingly, this dose–response relationship was not observed at higher NAC concentrations (100–200 μg/kg), suggesting a potential threshold beyond which NAC loses efficacy in these specific parameters. Our results suggest that the localized administration of N-acetylcysteine shows promise as a therapeutic strategy for OHSS by modulating key parameters associated with the syndrome. These promising results warrant further investigation into its mechanisms and efficacy, potentially expanding therapeutic options for OHSS management.

Cisplatin (CIS) is a potent chemotherapeutic agent primarily used to treat hematologic malignancies and solid tumors, including lymphomas, sarcomas, and some carcinomas. Patients receiving this treatment for tumors outside the nervous system develop cognitive impairment. Alterations in the kynurenine pathway (KP) following CIS treatment suggest that certain KP metabolites may cross the blood–brain barrier, leading to increased production of the neuromodulator kynurenic acid (KYNA), which is associated with cognitive impairment. This study aimed to evaluate the effects of modulating brain KYNA levels by the administration of N-acetylcysteine (NAC), an inhibitor of kynurenine aminotransferase II (KATII), an enzyme responsible for KYNA biosynthesis on the cognitive and neuromuscular deficits induced by CIS. Female Wistar rats were divided into four groups: control, NAC (300 mg/day/8 days), CIS (3 mg/kg i.p/5 days), and NAC + CIS (both treatments co-administered in parallel). Seven days after the last CIS administration, cognitive performance, muscle strength, brain KYNA levels, KATII activity, and brain tissue redox profile (lipid peroxidation and oxidized/reduced glutathione (GSH/GSSG) ratio) were assessed. CIS did not affect short-term memory but induced long-term memory deficits and reduced muscle strength, effects which were prevented by NAC co-administration. CIS decreased the GSH/GSSG ratio and the number of cells in the brain cortex while it increased lipid peroxidation, KYNA levels, and marginal KATII activity. All these effects were attenuated by the co-administration of NAC. These findings suggest that NAC mitigates the side effects of CIS, such as chemo-brain and muscle weakness, by improving the redox imbalance and modulating KYNA levels by limiting its non-enzymatic production by reactive oxygen species (ROS).

This article links the notion of rhizome with the field of migration studies, specifically to reflect on the vitality and political becoming of in-transit migrants passing through Mexico irregularly. Under this light, we aim to answer the following questions: How can we interpret the movements traced by undocumented migrants in transit? With what connections do they pass or not pass intensities that allow them to move? What is the political becoming of this migratory journey? The rhizome category is used as a methodological figuration to explore the paths, journeys, and walkers constituted in this becoming, in order to situate and map the collective resistances and singular experiences that emerge from these displacements. The working thesis asserts that irregularized migration in transit articulates an ongoing political process. Migrants who transit without the required legal documentation, when confronting a border order, create spaces outside State control and configure a type of politicized subjectivity. We applied a multi-situated ethnography, by following up the migrant caravan that crossed Mexico from its southern border up to reaching Tijuana, at its northern border, at the end of 2018, and employed observation and in- depth interviews techniques to document migrants’ experiences, movements, journeys, and displacements. Findings allowed us to map the creative, singular, and collective resistances that are woven during these transits and that somehow challenge the regime of control and borders.

El presente artículo muestra las formas de precarización laboral en términos de tiempo, contratos y salarios, enfocándose en los docentes a tiempo parcial y “hora-clase”, que constituyen la mayor parte de la población educativa en instituciones de educación superior. La metodología empleada parte de un análisis conceptual basado en artículos que abordan el creciente problema de la precariedad laboral en el sector educativo latinoamericano. Este problema es el resultado de la adopción de modelos neoliberales desde los años ochenta, que priorizan la eficiencia y la maximización de la producción. La desregulación de los contratos y la subcontratación han dado lugar a una proliferación de trabajos flexibles, lo que ha deteriorado la seguridad laboral y las condiciones de la comunidad docente. Además, el estudio destaca la situación particularmente incierta de los docentes “hora-clase” y no sindicalizados, quienes enfrentan salarios desproporcionados y una sensación de invisibilidad. En definitiva, es profundamente preocupante el escenario en que se encuentran los docentes de educación superior con condiciones de precariedad laboral, en especial si se lleva un estandarte de calidad educativa, y si se antepone el cumplimiento de parámetros y resultados al bienestar de los docentes.

The Chlamydiaceae are a family of obligate intracellular bacteria known for their unique biphasic developmental cycle. Chlamydial are associated with various host organisms, including humans, and have been proposed as emerging pathogens. Genomic studies have significantly enhanced our understanding of chlamydial biology, host adaptation, and evolutionary processes. In this study, we conducted a complete pangenome association analysis (pan-GWAS) using 101 genomes from the Chlamydiaceae family to identify differentially represented genes in Chlamydia and Chlamydophila, revealing their distinct evolutionary strategies for interacting with eukaryotic hosts. Our analysis identified 289 genes with differential abundance between the two clades: 129 showed a strong association with Chlamydia and 160 with Chlamydophila. Most genes in Chlamydia were related to the type III secretion system, while Chlamydophila genes corresponded to various functional categories, including translation, replication, transport, and metabolism. These findings suggest that Chlamydia has developed a high dependence on mammalian cells for replication, facilitated by a complex T3SS for intracellular manipulation. In contrast, the metabolic and functional diversity in Chlamydophila allows it to colonize a broad range of hosts, such as birds, reptiles, amphibians, and mammals, making it a less specialized clade.

Urbanization has reshaped the distribution of biodiversity on Earth, but we are only beginning to understand its effects on ecological communities. While urbanization may have homogenization effects strong enough to blur the large-scale patterns in interaction networks, urban community patterns may still be associated with climate gradients reflecting large-scale biogeographical processes. Using 103 hummingbird–plant mutualistic networks across continental Americas, including 176 hummingbird and 1,180 plant species, we asked how urbanization affects species interactions over large climate gradients. Urban networks were more generalized, exhibiting greater interaction overlap. Higher generalization was also associated with lower precipitation in both urban and natural areas, indicating that climate affects networks irrespective of habitat type. Urban habitats also showed lower hummingbird functional trait diversity and over/underrepresentation of specific clades. From the plant side, urban communities had a higher prevalence of nonnative nectar plants, which were more frequently visited by the hummingbird species occurring in both urban and natural areas. Therefore, urbanization affected hummingbird–plant interactions through both the composition of species and traits, as well as floral resource availability. Taken together, we show that urbanization consistently modifies ecological communities and their interactions, but climate still plays a role in affecting the structure of these novel communities over the scale of continents.

The diversity of interspecific interactions is a key part of biodiversity, but its response to anthropogenic disturbance and seasonal changes remains poorly understood. We explored the effects of habitat disturbance (from oak forest to induced pasture) and seasonality (dry vs. rainy) on the alpha diversity and evenness of ant–plant interaction networks in two temperate forests of central Mexico. Over three years, we conducted observations of ant–plant interactions monthly in La Malinche National Park and Flor del Bosque State Park, constructed quantitative networks based on interaction frequency. Using Hill numbers, we calculated alpha interaction diversity and evenness, analyzing both individual sites and pooled data. Disturbance significantly reduced interaction diversity for dominant interactions (q = 2) in both sites and reduced evenness in Flor del Bosque. Seasonal differences were evident, with higher alpha interaction diversity during the rainy season, particularly in the induced pasture in La Malinche and in the oak forest in Flor del Bosque. Evenness was higher during the dry season in the oak forest in Flor del Bosque. The same tendencies were observed when the data were pooled. Our results suggest that the disturbance and seasonal resource shifts simplify interaction networks, potentially affecting ecosystem functioning. This highlights the importance of considering interaction-level processes in biodiversity and conservation strategies.

Introduction Organic wastes are composted to increase their plant nutritional value, but little is known about how this might alter the bacterial and archaeal community structure and their genes. Methods Cow manure was collected from three local small-scale farmers and composted under controlled conditions, while the bacterial and archaeal communities were determined using shotgun metagenomics at the onset and after 74 days of composting. Results The bacterial, archaeal, methanogen, methanotrophs, methylotroph, and nitrifying community structures and their genes were affected by composting for 74 days, but the original composition of these communities determined the changes. Most of these archaeal and bacterial groups showed considerable variation after composting and between the cow manures. However, the differences in the relative abundance of their genes were much smaller compared to those of the archaeal or bacterial groups. Discussion It was found that composting of different cow manures did not result in similar bacterial or archaeal communities, and the changes that were found after 74 days were defined by the original populations. However, more research is necessary to determine if other composting conditions will give the same results.

Global warming is threatening ectotherms, with strong repercussions on their population dynamics. Body temperature in ectotherm reptiles is crucial to perform all their biological functions, which are maximized within a narrow interval. When faced with new or adverse thermal conditions, reptiles will respond with distributional changes, behavioural adjustments to maintain their internal temperature, or by adapting to the new environment, otherwise, extinctions will occur. Higher temperatures may have negative repercussions, for example, shortening periods of activity, affecting embryo development during gestation or decreasing viability of sperm cells in males. Through behavioural thermoregulation, reptiles can compensate for environmental variations (Bogert effect). Furthermore, according to Janzen’s hypothesis, the physiological cost of responding to adverse thermal conditions will be low in species exposed to higher thermal overlap. Here, we analysed the effect of a change in the thermal regime on sperm cell viability in Sceloporus megalepidurus, a small viviparous lizard from central Mexico. We hypothesized that an active thermoregulator inhabiting temperate mountains is able to prevent the effects of thermal change on sperm cell viability. We found that the change in thermal regime did not modify sperm cell viability, nor does it affect the maturation of sperm cells in the epididymis. Our results support the Bogert effect and suggest that, despite the high temperatures and low thermal quality, S. megalepidurus can maintain its body temperature within an optimal range for sperm cell viability.

Silicon dioxide nanoparticles are receiving increasing attention due to their new properties and wide applications. The aim of this study was to investigate the cytotoxic potential of 300 nm SiO2 nanospheres on erythrocytes using thermal diffusivity values. Cytotoxicity was correlated with thermal diffusivity of the hemolysates; thermal values were from 10.00 ± 0.40 × 10− 4 cm²/s to 12.20 ± 0.07 × 10− 4 cm²/s. The concentrations tested were 50, 100, 200, 400 and 800 µg/ml of silica nanoparticles. To evaluate cytotoxicity, human erythrocytes were obtained. Hemolytic damage in red blood cells had an exponential behavior dependent on the concentration of SiO2 nanostructures. The use of concentrations of 800 µg/ml exceeds the limit of compatibility for human red blood cells. Antioxidant enzyme quantification assays were also performed in which a dose-dependent depletion of catalase activity levels and an increase in glutathione S-transferase was observed. Therefore, oxidative stress was suggested as a mechanism of toxicity in erythrocytes.

Genome-resolved metagenomics, based on shotgun sequencing, has become a powerful strategy for investigating animal-associated microbiomes, due its heightened capability for delivering detailed taxonomic, phylogenetic, and functional insights compared to amplicon sequencing-based approaches. While genome-resolved metagenomics holds promise across various non-lethal sample types, their effectiveness in yielding high-quality metagenome-assembled genomes (MAGs) remains largely unexplored. Our investigation of fecal and cloacal microbiota of the mesquite lizards ( Sceloporus grammicus ) using genome-resolved metagenomics revealed that fecal samples contributed 97% of the 127 reconstructed bacterial genomes, whereas only 3% were recovered from cloacal swabs, which were largely enriched with host DNA. Taxonomic, phylogenetic and functional alpha microbial diversity was greater in fecal samples than in cloacal swabs. We also observed significant differences in microbial community composition between sampling methods, and higher inter-individual variation in cloacal swabs. Bacteroides , Phocaeicola and Parabacteroides (all Bacteroidota) were more abundant in the feces, whereas Hafnia and Salmonella (both Pseudomonadota) increased in the cloaca. Functional analyses showed that metabolic capacities of the microbiota to degrade polysaccharides, sugars and nitrogen compounds were enriched in fecal samples, likely reflecting the role of the microbiota in nutrient metabolism. Overall, our results indicate that fecal samples outperform cloacal swabs in characterizing microbial assemblages within lizards using genome-resolved metagenomics.

In women and animal models, hypothyroidism induces hypercholesterolemia, pancreatitis, and insulitis. We investigated whether lipids are involved in the effects of hypothyroidism in the pancreas. Control (n = 6) and hypothyroid (n = 6) adult female rabbits were used. We quantified serum and pancreatic triacylglycerol and total cholesterol levels, the oxidative and antioxidant status, and the expression of low‐density lipoprotein cholesterol receptor (LDLR) in the pancreas. Inflammation of the pancreas was evaluated by infiltration of immune cells positive to CD163 and α‐farnesoid receptor (FXRα). Other lipid players involved in both inflammation and insulin secretion of the pancreas, such as lanosterol 14‐α‐demethylase (CYP51A1), β‐farnesoid receptor (FXRβ), 3β‐hydroxysteroid dehydrogenase (3β‐HSD), and peroxisome proliferator‐activated receptor β (PPARβ/δ), were quantified. Groups were compared by t‐Student or U‐Mann–Whitney tests (p ≤ 0.05). Hypothyroidism induced hypercholesterolemia and a high cholesterol accumulation in the pancreas of female rabbits, without affecting oxidative or antioxidative status nor the expression of LDLR. The pancreas of hypothyroid females showed inflammation identified by a great infiltration of immune cells, macrophages CD163+, and loss of expression of FXRα+ in immune cells. Moreover, a reduced expression of CYP51A1, FXRβ, and PPARβ/δ, but not 3β‐HSD, in the hypothyroid pancreas was found. Pancreatitis and insulitis promoted by hypothyroidism may be related to the accumulation of cholesterol, lanosterol actions, and the activation of PPARβ/δ. All inflammatory markers evaluated in this study are related to glucose regulation, suggesting the link between hypothyroidism and diabetes.

Immune defense is fundamental to diminish the negative effects of the attack of infectious agents, yet the activation of the immune system entails costs and may compromise other life history-traits such as reproduction. In reproductive brown booby pairs (Sula leucogaster), we experimentally imposed an immune challenge during incubation, by intraperitoneally injecting Escherichia coli lipopolysaccharide (LPS), in either the male or the female. We aimed to test whether activation of the immune response results on: (1) an increase in oxidative stress parameters, (2) a decline in post-hatching parental care in the treated individual, and (3) a compensation of the post-hatching parental effort by the non-treated mate. We found that activation of the immune response during incubation did not increase oxidative damage to lipids or total antioxidant capacity. However, mounting an immune response compromised parental effort during the chick rearing period: compared to controls, LPS-treated parents showed roughly a 50% decline in the rate of preening and offspring feeding in response to begging. Interestingly, mates of LPS-treated parents increased their feeding rate suggesting parental care compensation. According to a scenario of full compensation, the decline in parental effort of LPS-treated parents did not result in poorer offspring growth or immune response, or increased levels of oxidative stress parameters. These findings suggest that in a long-lived species with long-lasting biparental care, an immune challenge compromises parental care, favoring parental compensation as a strategy to mitigate costs in terms of offspring success.