Southeastern Mexico Research Articles

Presence of Trypanosoma cruzi (TcI) in different tissues of Didelphis virginiana from the metropolitan area of Merida, southeastern Mexico: Epidemiological relevance and implications for non-vector transmission routes.

Trypanosoma cruzi is mainly transmitted to mammals by vectors, but other transmission routes exist. Opossums can harbor the infectious form of the parasite in their anal glands, underscoring their potential role in non-vectorial transmission. In Mexico, Didelphis virginiana and D. marsupialis are the main opossum species. While T. cruzi has been detected in the anal gland secretions of various opossum species, their infectivity has only been confirmed in D. marsupialis and D. albiventris. Vertical transmission has also been proposed in D. virginiana. However, if this occurs in opossums, it remains unclear whether it happens during pregnancy or lactation. Our objective was to investigate the possible contribution of urban opossums to non-vectorial transmission of T. cruzi in the metropolitan area of Merida, Yucatan, in southeastern Mexico. Blood, anal gland secretions, and milk were collected from opossums captured in Merida, Mexico, all identified as D. virginiana using taxonomic keys and Cytb sequencing. By PCR, T. cruzi was detected in 16/102 opossums (15.69%) in at least one type of sample. The prevalence was 14.71% (15/102) in blood and 0.98% (1/102) in anal gland secretions. 1/22 milk samples (4.55%) tested positive. Blood of 37 offspring from T. cruzi-positive mothers was collected and tested negative. qPCR revealed that females with offspring tended to have lower parasite load in blood compared to females without offspring and males. Genotyping of the parasite through multiplex PCR revealed only the DTU TcI. This study agrees with previous works where D. virginiana was the most abundant opossum species in urban areas in southeastern Mexico and confirms that it is associated with TcI. Detection of T. cruzi in a sample of anal gland secretions underscores the potential risk represented by D. virginiana in non-vectorial transmission in urban areas of southeastern Mexico. Detection in the milk of a lactating female, along with the observed tendency towards a lower parasite load in females with offspring, highlight the importance of further investigating vertical transmission in D. virginiana.

Prediction of environmental suitability for Haematoxylum campechianum: a proposal to promote reforestation in Mexico

Models of potential distribution and ecological niche allow to estimate priority areas for the management of species of interest, as well as to identify variables related to environmental suitability and predict the behavior of species in the face of anthropogenic disturbances. Logwood (Haematoxylum campechianum) is a species that we consider a natural heritage in southeastern Mexico because of its ecological role and the current and historical use of its wood. This species is present in different vegetation types and even dominates in some ecosystems called "tintales", which have been exploited for dye extraction in past centuries. This, combined with changes in land use for livestock, agriculture, and other anthropogenic activities, has affected the Logwood´s distribution and connectivity of its populations. We modeled the potential distribution of H. campechianum and evaluated the feasibility of reforestation with this species in southeastern Mexico. For this purpose, we included 638 occurrence points and used the MaxEnt algorithm for modeling, analyzing different parameters. We used the potential distribution model, accessibility to the areas and water availability to calculate a feasibility index for reforestation. The environmental suitability for the species is more present in southeastern Mexico, conditioned by the aridity index, the maximum temperature of the coldest month and the warmest month. The greatest percentage of areas with high feasibility indexes for reforestation are found in Campeche, apparently a key state for the conservation and management of the species. This study can be the starting point for implementing reforestation programs with H. campechianum and can be used as an example to apply to other species with patrimonial value.

Historical (1960 – 2011) and spatial analysis of mercury and arsenic in two species of tropical birds in southeastern Mexico

Historical (1960 – 2011) and spatial analysis of mercury and arsenic in two species of tropical birds in southeastern Mexico

DOES RESIN TAPPING AFFECT THE TAPERING AND ACCUMULATION OF MERCHANTABLE TIMBER VOLUME IN PINE TREES?

Form factors and taper functions are used for the quantitative and qualitative description of tree stem shape. In southeastern Mexico, there are plantations of Pinus caribaea var. hondurensis (Sénécl.) W.H. Barrett & Golfari, Pinus elliottii var. elliottii Engelm., and hybrids between these species to simultaneously produce resin and wood. Farmers need to know whether the practice of resin tapping to death has a negative impact on tree shape and volume of the wood produced. To answer these questions, this study compared the shape, taper, and volume of resin-tapped and untapped trees from three P. caribaea origins. A total of 198 trees (99 resin-tapped and 99 untapped) were measured in all diameter categories of the plantation. Total volume models, along with a compatible taper system and variable merchantable timber volume, were fitted using linear and nonlinear regression analyses. To compensate for the lack of initial tree size data prior to tapping, indicator variables (dummies) and an additive structure were used to parameterize volume and taper models. Untapped trees accumulated greater volume than tapped trees. In contrast, the form factor (ff) of resin-tapped trees (ff = 0.51) was greater than that of untapped trees (ff = 0.45). The form factor increased due to tapping between 4 and 7 % depending on the origin, although the hybrid P. caribaea × P. elliottii presented the most desirable stem geometry in tapped and untapped trees. Based on the Demaerschalk model, the variability is estimated at 99 and 97 % of the merchantable and taper volumes, respectively.

Impact Level of Post-COVID-19 Burnout Syndrome in a University in Southeastern Mexico

Objective: The objective of this study is to determine the level of impact of post-COVID-19 Burnout Syndrome in the Faculty of Accounting and Administration at a university in Southeastern Mexico. Theoretical Framework: A diagnosis of post-COVID-19 stress levels and their relationship with tutoring activities in the teaching-learning process is designed and developed, highlighting the importance of mental health as established by the World Health Organization (WHO) and the International Labour Organization (ILO). Method: The universe for this research will be one of the university’s affiliated centers. The methodology will be descriptive, using a questionnaire to measure three important aspects: emotional exhaustion, depersonalization, and personal accomplishment. Results and Discussion: The results revealed high levels of emotional exhaustion in both students and tutors, as well as elevated levels of depersonalization. Lastly, most of the evaluated population shows low levels of personal accomplishment. Based on these results, it is suggested to implement actions for the tutorial action plan to prevent stress-related situations like those associated with Burnout Syndrome. Research Implications: This study presents a positive perspective, providing an opportunity to help students adapt to new situations, while tutors remain alert and motivated to prevent dangers such as chronic stress, depression, and suicide. Tutorial action is oriented towards providing the necessary attention to students during their academic journey, enabling them to achieve adequate academic performance. Originality/Value: This article offers an innovative perspective on burnout syndrome in the university environment. The uniqueness of this work lies in its diagnostic approach, which not only reveals the manifestations of burnout through attitudes, emotions, and beliefs, but also emphasizes the importance of early intervention.

Strengthening Community Resilience in the Face of Environmental and Economic Challenges in Southeast Mexico

Objective: The problems in the sustainable management of natural resources in their fishing practices in the community of Aztlán Quinta Seccion Palomillal in Tabasco, Mexico, are analyzed to develop community solutions and improve sustainability and socioeconomic results. Theoretical Framework: It is based on the theory of sustainability (World Commission on Environment and Development, 1987, p. 43), the natural resources management model (Natural Resources Commission, 2012, p. 3) and the theory of participatory research (Reason & Bradbury, 2008, p. These frameworks are the context in which fishing practices are developed in the community, serving as a relevant case study for southeastern Mexico, facilitating the analysis of the problems and proposed solutions. Method: A qualitative case study design focused on community-based participatory research was applied, involving key community actors, including fishermen and leaders of the fishing cooperative. Data collection was through semi-structured interviews, focus groups and participant observation. The interviews were designed to learn about challenges in resource management, while focus groups facilitated discussions about possible solutions. Participant observations were carried out during community meetings and the sociocultural and environmental context. Results and Discussion: The problems of sediment accumulation, the presence of invasive species, the lack of adequate infrastructure and low educational levels were identified. There is an urgency to implement strategies that combine traditional knowledge with modern practices to improve the sustainability of fishing activities. The importance of community participation is highlighted. Research Implications: It has significant practical and theoretical implications for sustainable resource management in rural fishing communities and can be applied in other similar rural contexts and contributes to the theoretical development of community-based participatory research. Originality/Value: An innovative community-based participatory research approach is applied for sustainable natural resource management in a rural fishing community, replicable for sustainable resource management in vulnerable contexts.

Elements, Contexts, and Attributes of Teacher Leadership Identified by College Professors in southeastern Mexico

Teacher leadership has its beginnings in Western countries as a response to fast changes that have taken place in the social, political, and economic environments. Currently in the Latin American context it has become a focus of interest for educational researchers particularly because the incipient research on the topic in these contexts. This study focused on knowing the elements, contexts, and attributes identified by college teachers about teacher leadership southeastern Mexico. All full-time faculty from a college at a public university (50) participated in this study, 20% of whom have formal administrative functions in addition to their teaching. The main findings show that: the main elements that are related to the concept of teacher leadership are behaviors focused on interpersonal relationships and school innovation. Regarding the contexts, the development of teacher leadership is often based on institutional context and collaborative work. Regarding the attributes, special emphasis is placed on interpersonal relationships, change, and individual development and recognition. No significant differences were found in the perceptions of participants who have an administrative appointment and those who do not, regarding the contexts and attributes of teacher leadership, except for the elements of the concept of teacher leadership between men and women.

Elements, Contexts, and Attributes of Teacher Leadership Identified by College Professors in southeastern Mexico

Teacher leadership has its beginnings in Western countries as a response to fast changes that have taken place in the social, political, and economic environments. Currently in the Latin American context it has become a focus of interest for educational researchers particularly because the incipient research on the topic in these contexts. This study focused on knowing the elements, contexts, and attributes identified by college teachers about teacher leadership southeastern Mexico. All full-time faculty from a college at a public university (50) participated in this study, 20% of whom have formal administrative functions in addition to their teaching. The main findings show that: the main elements that are related to the concept of teacher leadership are behaviors focused on interpersonal relationships and school innovation. Regarding the contexts, the development of teacher leadership is often based on institutional context and collaborative work. Regarding the attributes, special emphasis is placed on interpersonal relationships, change, and individual development and recognition. No significant differences were found in the perceptions of participants who have an administrative appointment and those who do not, regarding the contexts and attributes of teacher leadership, except for the elements of the concept of teacher leadership between men and women.

Life history of Mexican species of the genus <i>Tlaloc</i> (Cyprinodontiformes, Profundulidae)

Fish of the genus Tlaloc are distributed from southern Mexico to Central America and are a distinctive example of the endemic fauna of the Mesoamerican highlands, which has been scarcely studied in Mexico. The present study provides basic life-history data for the species Tlaloc hildebrandi, T. candalarius, and T. labialis, which are native to the headwaters of the Grijalva-Usumacinta basin in southeastern Mexico. We collected 918 specimens to determine their Length-Weight Relationship (LWR), Relative Condition Factor (Kr), sex ratio, Gonadosomatic Index (GSI), fecundity, and size at first sexual maturity. Both sexes of all species had positive allometric growth, except for T. candalarius females (isometric). Mean Kr and sex ratio values differed significantly among species. Females’ GSI values differed significantly among species but were highest during the dry season in all three species. Absolute fecundity was positively correlated with standard length and weight. Sexual maturity was reached at different lengths among species. Based on these results, we suggest that all three species present an opportunistic life strategy, which is very common in fish of the order Cyprinodontiformes. These results represent a first contribution on the life-history of this group of fish and provide basic information that is fundamental to ensuring their conservation.

Analysis of Groundwater Quality in Rural Homes in Southeastern Mexico: Comparison of Treatment Methods

Analysis of Groundwater Quality in Rural Homes in Southeastern Mexico: Comparison of Treatment Methods

Regeneration of the caudal fin of the evolutionary ancient tropical gar Atractosteus tropicus

BackgroundThe tropical gar (Atractosteus tropicus), a member of the Lepisosteidae family, is native to regions extending from southeastern Mexico to southern Costa Rica. This species serves as a unique bridge between tetrapods and teleosts due to its phylogenetic position, slow evolutionary rate, dense genetic map, gene similarities with humans, and ease of laboratory cultivation. As a taxonomic sister group to teleosts like the zebrafish (Danio rerio), known for its high regenerative capacity, it remains unclear whether the tropical gar shares a similar ability for regeneration.ResultsThis study aims to elucidate the caudal fin regeneration process in tropical gar through skeletal and histological staining methods. Juvenile specimens were observed over a two-month period, during which they were fed brine shrimp, and anesthetized with 1% eugenol for caudal fin amputation. Samples were collected at various days post-amputation (dpa). Alcian blue and alizarin red staining were used to highlight skeletal regeneration, particularly the formation of new cartilage, while histological staining with hematoxylin and eosin was performed to observe tissue regeneration at the amputation site.ConclusionsThe findings reveal a remarkable ability for caudal fin regeneration in juvenile tropical gar. Given the Garfish evolutionary relationship with teleosts, this opens new avenues for research into tissue regeneration across different groups of Actinopterygii.

Learning styles and regulation of task value in new university students

International organizations’ analyses of Mexican students have shown that the nation's educational system is currently facing significant challenges in its ability to support the development of academic skills at all educational levels. Evaluations carried out by international organizations on Mexican students have revealed that the educational system in this country currently presents serious difficulties in effectively contributing to the development of academic skills at all educational levels. Models that consider learning styles and other factors that support academic performance such as intrinsic motivation, mastery goals, beliefs, control and Regulation of the Value of Tasks (RVT) have been developed since the last century to improve the skills of both high school and university students. A quantitative, non-experimental, cross-sectional, descriptive and correlational study was conducted to identify the relationship between Regulation of the Value of Tasks (RTV) and learning style (LS). RTV data collection used the motivated strategies for learning questionnaire while EA was assessed using the Honey-Alonso Learning Styles Questionnaire (CHAEA). The study involved 108 university students enrolled in a public institution located in southeastern Mexico. The results indicate a "very weak" relationship between SRL and the active, pragmatic and theoretical learning styles. According to the literature review conducted for this study, there are very few similar investigations making it difficult to compare the results with previous data. Further research is suggested to explore the relationship between these variables in other populations.

Estado de excepción neoliberal y resistencia en el sureste de México

In November 2021, the President of Mexico (2018-2024) declared that the priority megaprojects of the National Development Plan (Maya Train, Isthmus of Tehuantepec Interoceanic Corridor, Dos Bocas Refinery) fall within the realm of national security. Public and private investments in these projects are directed towards southeastern Mexico, covering the states of Oaxaca, Chiapas, Quintana Roo, Campeche, Yucatán, and Tabasco. These regions are home to indigenous peoples and communities that hold 45% of Mexico’s total social property. In some cases, these communities are visibly linked to national political organizations that defend land and territory. The decree is considered a state of exception applied to land-territory use, with dual implications. On one hand, it represents the undivided social field monopolized by monetary metrics. On the other hand, it signifies the expansion of a neocolonial condition promoted by the Mexican federal government, which marginalizes the voice of resistance in favor of adopting the capital logic defined by the stratification of the global economy. The methodology involves participatory action research since 2019, collaborative research through the coordination of workshops, caravans, marches, and political-community meetings, promoted in conjunction with assemblies fighting for territorial defense. We anticipate the increased use of such state of exception in response to the intertwined rise of health, environmental, and economic contingencies that drive the economic cycle, coupled with ineffective governmental policies formulated for regular times. In other words, the state of exception is activated to ensure the continuity of capital accumulation driven by the concentration of private property.

Phenome-Wide Association Study of Latent Autoimmune Diabetes from a Southern Mexican Population Implicates rs7305229 with Plasmatic Anti-Glutamic Acid Decarboxylase Autoantibody (GADA) Levels.

Latent autoimmune diabetes in adults (LADA) is characterized by the presence of glutamate decarboxylase autoantibodies (GADA). LADA has intermediate features between type 1 diabetes and type 2 diabetes. In addition, genetic risk factors for both types of diabetes are present in LADA. Nonetheless, evidence about the genetics of LADA in non-European populations is scarce. This study aims to perform a genome-wide association study with a phenome-wide association study of LADA in a southeastern Mexican population. We included 59 patients diagnosed with LADA from a previous study and 3121 individuals without diabetes from the MxGDAR/ENCODAT database. We utilized the GENESIS package in R to perform the genome-wide association study (GWAS) of LADA and PLINK for the phenome-wide association study (PheWAS) of LADA features. Nine polymorphisms reach the nominal association level (1 × 10-5) in the GWAS. The PheWAS showed that rs7305229 is genome-wide and associated with serum GADA levels in our sample (p = 1.84 × 10-8). rs7305229 is located downstream of the FAIM2 gene; previous reports associate FAIM2 variants with childhood obesity, body mass index, body adiposity measures, lymphocyte CD8+ activity, and anti-thyroid peroxidase antibodies. Our findings reveal that rs7305229 affects the GADA levels in patients with LADA from southeastern Mexico. More studies are needed to determine if this risk genotype exists in other populations with LADA.

Growth, chlorophyll fluorescence, and gas exchange of three maize landraces in southeastern Mexico

Background: Maize landraces show remarkable diversity and environmental adaptability in Mexico. Nevertheless, few studies have explored physiological mechanisms used by different maize landraces to grow and yield in a particular agroecological region. Question: How do three landrace maize populations from contrasting maize races in southeastern Mexico, differ in their responses in terms of growth, chlorophyll fluorescence, and gas exchange? Studied species: Zea mays L. Study site and date: Yucatan, Mexico; 2017. Methods: The field experiment followed a complete randomized block design, with six replicates. Three contrasting maize landraces were evaluated as treatments. Response variables were vegetative traits, dry matter allocation, yield components, and maize physiological responses. Data were analyzed by one-way ANOVA and post hoc Tukey multiple comparison test (P ≤ 0.05). Results: Maize landraces showed differences in cycle length, plant morphology, and yield performance. The long cycle maize landrace Xnuc-naal, had tall plants that accumulated 17 and 21 % more dry matter than Xmejen-naal and Elotillo, respectively. The short-cycle maize landraces Elotillo and Xmejen-naal exhibit superior physiological responses leading to higher grain yields compared to the Xnuc-naal. Conclusions: The landrace Xnuc-naal stood out for its ability in forage production, whereas Elotillo and Xmejen-naal exhibited notable physiological efficiency in grain production in southeastern Mexico.

Pathogen index in freshwater drum (Aplodinotus grunniens R.) from the usumacinta river in southeastern mexico (Aplodinotus grunniens R.) from the usumacinta river in southeastern mexico

Pathogen index in freshwater drum (Aplodinotus grunniens R.) from the usumacinta river in southeastern mexico (Aplodinotus grunniens R.) from the usumacinta river in southeastern mexico

GENETIC DIVERSITY OF Moringa oleifera Lam. IN SOUTHEASTERN MEXICO

Moringa oleifera Lam. is a plant with nutritional and nutraceutical properties. It was introduced from India to Mexico, and some of its ecotypes are cultivated for industrial use. These ecotypes show morphological variations, indicating genetic variation. Therefore, the purpose of this study was to evaluate eight simple sequence repeat (SSR) loci to assess the genetic diversity of 10 cultivated M. oleifera populations collected from the southeast of Mexico. All markers generated a total of 127 alleles, with 15.8 alleles per locus. The polymorphic information content of markers was 0.869, with an average heterozygosity of 0.194. At the population level, the Nei´s gene diversity was found to be 0.66, with 4.9 different alleles per locus and 5.2 genotypes on average per accession. The distribution of genetic variation was 20 % among populations, 58 % between individuals, and 22 % within individuals. The principal coordinate analysis (PcoA) plot and unweighted pair group method with arithmetic mean (UPGMA) linkage revealed three groups, corresponding to the three original genetic populations identified through structure analysis (Delta K = 3). Results showed significant differences in genetic diversity in M. oleifera populations stablished in Southeastern Mexico, which can be leveraged to increase the use of this germplasm.

Influence of Anastrepha host fruit size over parasitism by Diachasmimorpha longicaudata in open-field augmentative releases

ABSTRACT Fruit size can act as a physical barrier providing refuge for larvae of pest Anastrepha species against parasitoid attack. Therefore, the aim of this study was to evaluate the influence of fruit size in six fruit species infested by Anastrepha larvae on the parasitism of Diachasmimorpha longicaudata after its augmentative release. About 1500 parasitoids were weekly released in disturbed wild vegetation patches. Fruit sampling was performed at the Coastal Lowlands of the Soconusco Region, southeastern Mexico, between June 2021 and October 2022. Overall, 310 ripe fruits belonging to grapefruit, creole mamey (large-size fruits), sweet orange, creole mango, wild guava (medium-size fruits), and wild hog plum (small-size fruit) were collected. The length, frontal width, lateral width and pulp thickness of all sampled fruits were measured. Such physical characteristics are indicators of the fruit size. Fruit collection was performed 48 h after release. Results indicated an inverse correlation between fruit size and parasitism, with a significant r 2 value higher than 75%. Host larvae in all fruits were parasitised only by D. longicaudata. The highest mean parasitism, which exceeded 90%, was recorded on hog plum and the lowest, below 20%, on Citrus spp. and mamey. Results corroborated the influence of host fruit size on parasitism levels by D. longicaudata regardless of its large-scale, open-field releases. Augmentative releases of D. longicaudata can be focused on wilderness areas with prevalence of medium-size to small-size Anastrepha host fruits. This would encourage long-term sustainable conservation of released parasitoid populations.

Mangrove dynamics driven by Late Holocene drought at Laguna Bacalar, Mexico

Laguna Bacalar, one of Mexico's most significant near-coast lakes, remains underexplored in the context of its Late Holocene paleoecology. A 2,40 m long core was retrieved in northern Laguna Bacalar. Palynological and geochemical proxies were isolated and analyzed. Our findings reveal the intricate paleoecological dynamics and hydrodynamic shifts of this vital area in southeastern Mexico. Climate and ecological changes delineate three pivotal phases during the Late Holocene at Laguna Bacalar: (i) a period between 3600 and 3250 cal BP mirroring current climatic conditions with seasonal dry tropical forest and mangroves as the dominant vegetation and evidence of human activities indicated by the presence of fossil maize pollen, (ii) a relatively arid phase from 3250 to 2600 cal BP, influenced by heightened ENSO-driven precipitation variability and sea level rise favoring an estuarine environment at Laguna Bacalar, and (iii) a period between 2600 and 2200 cal BP, exhibiting hydrological conditions akin to contemporary conditions with wetland forest mangrove vegetation. These data ultimately underscore the region's susceptibility to regional climatic fluctuations and ecological resilience, providing a case study from which to predict future conditions and establish modern conservation policy for Laguna Bacalar and similar environments.

Single‑nucleotide polymorphisms in the promoter of the gene encoding for C‑reactive protein associated with acute coronary syndrome.

Acute coronary syndrome (ACS) is a leading cause of mortality worldwide. Several studies have shown that certain single nucleotide polymorphisms (SNPs) are linked to the development of ACS. In particular, C-reactive protein (CRP) has emerged as an important predictive biomarker for cardiovascular disease. The current study aimed to investigate four polymorphisms of the CRP gene as possible biomarkers for ACS in a sample of 252 individuals (114 patients with ACS and 138 healthy controls) from Southeastern Mexico. Multivariate analysis adjusted for clinical variables showed that the polymorphism 3872CT for the genotype CC/CT [adjusted Odds Ratio (AdOR)=3.78; 95% Confidence Interval (CI): 1.11-12.92; P=0.034] and the genotype GG/GC of the polymorphisms 2667CG (AdOR=4.82; 95% CI: 1.69-13.72; P=0.02) were associated with ACS. However, the polymorphisms 3006AC genotype AA/AC and 5237GA genotype GG/GC were not found to be associated in the multivariate analysis with ACS (P>0.05). These results suggested that 3872CC/CT and 2667CC/CG polymorphism of the CRP gene plays a significant role in the development of ACS.