Anthoceros subtilis and A. telaganus (Anthocerotaceae): two new records for America from the hornwort flora of Mexico

In a recent trip to southern Mexico, Anthoceros subtilis and A. telaganus were recorded for the first time in Mexico and the American continent. Several previous records of A. subtilis were from Asia and one from Africa, and A. telaganus is known only from Indonesia. The new range extension of these two species is reported and the species are described and illustrated. Mexican populations of A. subtilis are characterized by small brown spores (26–42 μm), similar ornamentation on proximal and distal spore surfaces with papillate to tuberculate projections. Anthoceros telaganus is characterized by larger black spores (32–53 μm) with a smooth strip along the trilete mark on the proximal surface. Molecular genetic sequencing is needed to test whether Asian and American populations of these morphologically similar but geographically disjunct taxa are conspecific.

Prevalence of protective haplotypes of the SLCO1B1 gene for statin transport in Mexican populations

Aim: To evaluate the genetic distribution of the rs4149056 and rs2306283 variants in the SLCO1B1 gene in Mexican Mestizo (admixed) and Native American groups. Materials & methods: We recruited 360 volunteers who were qPCR-genotyped with TaqMan probes. Results: Allele and genotype frequencies are reported. Among the expected rs4149056– rs2306283 haplotypes, T–A (42.35–58.47%) was the most prevalent which relates to the normal activity of the OATP1B1 transporter. This was followed by the T–G haplotype associated with further statin transport and cholesterol reduction (32.49–43.76%). Conclusion: Based on these SLCO1B1 gene variants, we confirmed that a minimum fraction of the Mexican study populations would be at risk from decreasing simvastatin transport and the development of statin-induced myopathy.

Effect of a conditional cash transference program on food insecurity in Mexican households: 2012–2016

Objective: To estimate the effects of the social inclusion programme PROSPERA on food insecurity (FI) in Mexican households during 2012 and 2016. Design: Quasi-experimental study using cross-sectional data from 2012 to 2016 National Household Income and Expenditure Survey – Socioeconomic Conditions Module (in Spanish, ENIGH-MCS). Setting: Data were used from a 2012 sample of 56 888 Mexican households (representative of 31 206 819 households) and a 2016 sample of 70 263 Mexican households (representative of 33 445 353 households). Severity of FI was estimated with the Mexican Food Security Scale (in Spanish, EMSA). The statistical analysis estimated a differences in differences (DD) model weighted by propensity score to compare program beneficiary and non-beneficiary households in 2012 than in 2016. We estimated the effect on households with and without children (< 18 years of age). We also compared this model to a DD model without propensity score weighting. Participants: Mexican households. Results: FI among all beneficiary households decreased 8·0pp as compared to non-beneficiary households over the study period. In beneficiary households with children, this decrease was 6·0pp and for beneficiary households without children, this decrease was 12·9pp (for all, P-value < 0·001). Conclusions: The PROSPERA program had a positive effect on FI reduction at the household level through increasing food access, which usually improves nutritional outcomes in vulnerable Mexican populations.

Prevalence of latent tuberculosis in patients with hematological neoplasms in a cancer referral hospital in Mexico City

Objective To determine the prevalence of Latent Tuberculosis in patients with hematological neoplasms at the Instituto Nacional de Cancerología in Mexico City using the Tuberculin skin test (TST). Methods This retrospective study included all patients with a recent diagnosis of hematological neoplasms who were admitted for treatment from 2017 to 2018 and who were screened for latent tuberculosis with the TST. The prevalence of latent tuberculosis in this group, tolerance and therapeutic adherence in treated patients are described. Results The files of 446 patients with hematological malignancy who had a TST were reviewed. The prevalence of latent tuberculosis was 31.2% (n = 139). Ninety-three patients received isoniazid, 15.1% had some adverse reactions, but only 4 (4.3%) had to discontinue treatment. Two patients with latent tuberculosis under treatment with Isoniazid reactivated tuberculosis infection. Conclusions The prevalence in our study was within the range of other similar Mexican populations. Isoniazid treatment had an adequate tolerance and adherence. Longer follow-up could offer more information on the risk of reactivation in both groups.

Population Diversity of Three Variants of the SLC47A2 Gene (MATE2-K transporter) in Mexican Mestizos and Native Americans

Background. MATE2-K is an efflux transporter protein of organic cation expressed mainly in the kidney and encoded by the SLC47A2 gene. Different variants of this gene have shown an impact on the pharmacokinetics of various drugs, including metformin, which represents one of the most widely used drugs in treating type 2 diabetes. The SLC47A2 gene variants have been scarcely studied in Mexican populations, especially in Native American groups. For this reason, we analyzed the distribution of the variants rs12943590, rs35263947, and rs9900497 within the SLC47A2 gene in 173 Native Americans (Tarahumara, Huichol, Maya, Puerépecha) and 182 Mestizos (admixed) individuals from Mexico. Methods and Results . Genotypes were determined through TaqMan probes (qPCR). The Hardy-Weinberg agreement was confirmed for all three SLC47A2 gene variants in all the Mexican populations analyzed. When worldwide populations were included for comparison purposes, for alleles and genotypes, a relative interpopulation homogeneity was observed for rs35263947 (C allele; range: 48.9–76.7%) and rs9900497 (G allele; range: 59.1–81.4%). Conversely, heterogeneity was evident for rs12943590 (G allele, range 40.9–77.9%), where the most differentiated population was the Huichol, with high frequencies of the risk genotype associated with decreased response to metformin treatment (A/A= 40.9%).Conclusions. Although the SLC47A2 gene variants allow predicting favorable response to the metformin treatment in Mexican populations, the probable high frequency of ineffectiveness should be discarded in Huichols.

Genetic diversity of divergent redclaw crayfish Cherax quadricarinatus (Von Martens, 1868) populations evaluated to initiate a breeding program in Mexico

Cherax quadricarinatus is a decapod crustacean of interest to the aquaculture industry. In Mexico, a significant effort has been made to improve biological requirements, but the genetic characteristics are unknown. We examined the genetic diversity and differentiation in four populations in Mexico (three commercial farms and one feral population), as well as one research line from Argentina, used as reference. To initiate a founder stock in a genetic improvement program, we analyzed five microsatellite markers. The genetic diversity in terms of the number of alleles was low to moderate (2.8-6.2) in Mexican populations than the Argentinean sample (8.8). A pairwise Wright's Fst analysis showed that all populations were significantly different (P < 0.5). Cross-breeding organisms from a different population are suggested to increase genetic variability before initiating a founder stock with higher genetic variation.

Dietary, Cultural and Pathogens-related Selective Pressures Shaped Differential Adaptive Evolution Among Native Mexican Populations

Native American genetic ancestry has been remarkably implicated with increased risk of diverse health issues in several Mexican populations, especially in relation to the dramatic changes in environmental, dietary and cultural settings they have recently undergone. In particular, the effects of these ecological transitions and Westernization of lifestyles have been investigated so far predominantly on Admixed individuals. Nevertheless, indigenous groups, rather than admixed Mexicans, have plausibly retained the highest proportions of genetic components shaped by natural selection in response to the ancient milieu experienced by Mexican ancestors during their pre-Columbian evolutionary history. These formerly adaptive alleles/haplotypes have the potential to represent the genetic determinants of some biological traits peculiar to the Mexican people and a reservoir of loci with potential biomedical relevance. To test such a hypothesis, we used high-resolution genomic data to infer the unique adaptive evolution of 15 Native Mexican groups selected as reasonable descendants of the main pre-Columbian Mexican civilizations. A combination of haplotype-based and gene-network analyses enabled us to detect genomic signatures ascribable to polygenic adaptive traits evolved by the main genetic clusters of indigenous Mexican populations to cope with local environmental and/or cultural conditions. Some of them were also found to play a role in modulating the susceptibility/resistance of these groups to certain pathological conditions, thus providing new evidence for diverse selective pressures having contributed to shape current biological and disease-risk patterns in present-day Native and Mestizo Mexican populations.

Concentration–Mortality Response of Mexican Populations Fall Armyworm (Lepidoptera: Noctuidae) to Commercial Formulations of Bacillus Thuringiensis

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is the most economically important pest of maize (Zea mays L.) grown in Mexico. In order to identify biologically based management tactics for this pest, we determined the concentration–mortality response of 16 S. frugiperda populations collected in Mexico to two commercial formulations of Bacillus thuringiensis Berliner (Bt) (XenTari® [Bt subsp. aizawai] and DiPel® [Bt subsp. kurstaki]; Valent de México SA De CV, Jalisco, México). Laboratory bioassays established median lethal concentrations (LC50s) for each Bt formulation × population combination. We also determined mean larval weight 7 d after exposure and the number of larvae that reached the third instar of development. The populations were susceptible to both Bt formulations but they were, overall, more susceptible to Bt subsp. aizawai (XenTari) than to Bt subsp. kurstaki (DiPel). These results can serve as a reference to detect changes in S. frugiperda response to these Bt commercial products over time.

Susceptibility of Fall Armyworms (Spodoptera frugiperda J.E.) from Mexico and Puerto Rico to Bt Proteins

Fall armyworm is one of the main pests of conventional and Bacillus thuringiensis (Bt) corn in many countries in the Americas, Africa, Asia and in Australia. We conducted diet-overlay bioassays to determine the status of susceptibility to four Bt proteins (Cry1A.105, Cry2Ab2, Cry1F and Cry1Ac) in three different populations of fall armyworm from Mexico, and one population from Puerto Rico. Bioassays showed that fall armyworms from Puerto Rico were resistant to Cry1F with a resistance ratio 50 (RR50) higher than 10,000 ng/cm2 and to Cry1Ac with a RR50 = 12.2 ng/cm2, displaying the highest median lethal concentration (LC50) values to all Bt proteins tested. The effective concentration 50 (EC50) values further confirmed the loss of susceptibility to Cry1F and Cry1Ac in this population. However, LC50 and EC50 results with Cry1A.105 and Cry2Ab2 revealed that fall armyworm from Puerto Rico remained largely susceptible to these two proteins. The Mexican populations were highly susceptible to all the Bt proteins tested and displayed the lowest LC50 and EC50 values to all Bt proteins. Our results suggest that Cry1F and Cry1Ac resistance is stable in fall armyworm from Puerto Rico. However, this population remains susceptible to Cry1A.105 and Cry2Ab2. Results with Mexican fall armyworms suggest that possible deployment of Bt corn in Mexico will not be immediately challenged by Bt-resistant genes in those regions.

Development of an index to assess adherence to the traditional Mexican diet using a modified Delphi method

Objective: Promoting a traditional Mexican diet (TMexD) could potentially reduce high rates of non-communicable diseases (NCDs) and support food sustainability in Mexico. This study aimed to develop an index to assess adherence to the TMexD. Design: A three-round Delphi study was conducted to examine the food groups, specific foods, and food-related habits that would constitute a TMexD index. Participants selected the TMexD items using Likert scales, lists of responses, and yes/no questions. Consensus was determined using percentages of agreement, mean values and/or coefficients of variation. Setting: Online Delphi study. Participants: Seventeen nutrition and food experts in Mexico completed all three rounds. Results: The resulting index (ranging from 0 to 21 points) consisted of 15 food groups, containing 102 individual foods. Food groups included in higher quantities were maize, other grains, legumes, vegetables, fruits, herbs, nuts and seeds, and tubers. Animal foods, vegetable fats and oils, home-made beverages, maize-based dishes, and plain water were also included, but in lower quantities. The food-related habits included were consuming home-made meals, socialising at meals, and buying food in local markets. Consensus was reached for all index items apart from quantities of consumption of six food groups (herbs, nuts, grains, tubers, dairy, and eggs). Conclusions: Although future research could improve the measures for which consensus was not reached, the TMexD index proposed in this study potentially displays a healthy and sustainable dietary pattern and could be used to examine links between the TMexD and health outcomes in Mexican populations.