Desert plants, arbuscular mycorrhizal fungi and associated bacteria: Exploring the diversity and role of symbiosis under drought.

Desert plants, such as Agave tequilana, A. salmiana and Myrtillocactus geometrizans, can survive harsh environmental conditions partly due to their symbiotic relationships with microorganisms, including arbuscular mycorrhizal fungi (AMF). Interestingly, some of these fungi also harbour endosymbiotic bacteria. Our research focused on investigating the diversity of these AMFs and their associated bacteria in these plants growing in arid soil. We found that agaves have a threefold higher AMF colonization than M. geometrizans. Metabarcoding techniques revealed that the composition of AMF communities was primarily influenced by the plant host, while the bacterial communities were more affected by the specific plant compartment or niche they inhabited. We identified both known and novel endofungal bacterial taxa, including Burkholderiales, and confirmed their presence within AMF spores using multiphoton microscopy. Our study also explored the effects of drought on the symbiosis between A. tequilana and AMF. We discovered that the severity of drought conditions could modulate the strength of this symbiosis and its outcomes for the plant holobiont. Severe drought conditions prevented the formation of this symbiosis, while moderate drought conditions promoted it, thereby conferring drought tolerance in A. tequilana. This research sheds light on the diversity of AMF and associated bacteria in Crassulacean Acid Metabolism (CAM) plants and underscores the crucial role of drought as a factor modulating the symbiosis between A. tequilana and AMF. Further research is needed to understand the role of endofungal bacteria in this response.

Phytochemical Analysis and Antioxidant and Anti-Inflammatory Capacity of the Extracts of Fruits of the Sechium Hybrid.

In addition to their own antioxidants, human cells feed on external antioxidants, such as the phenolic compounds of fruits and vegetables, which work together to keep oxidative stress in check. Sechium edule, an edible species of chayote, has phenolic compounds with antioxidant activity and antineoplastic activity. A Sechium hybrid shows one thousand times greater antineoplastic activity than edible species, but its antioxidant and anti-inflammatory activities and the content of phenolic compounds are unknown. The aim of this study was to determine the antioxidant and anti-inflammatory capacity of the extract of fruits of the Sechium hybrid in vitro and in vivo. Phytochemical analysis using HPLC showed that the extract of the Sechium hybrid has at least 16 phenolic compounds; galangin, naringenin, phloretin and chlorogenic acid are the most abundant. In an in vitro assay, this extract inhibited 2,2-diphenyl-L-picrylhydrazyl (DPPH) activity and protected the dimyristoylphosphatidylethanolamine (DMPE) phospholipid model cell membrane from oxidation mediated by hypochlorous acid (HClO). In vivo, it was identified that the most abundant metabolites in the extract enter the bloodstream of the treated mice. On the other hand, the extract reduces the levels of tumor necrosis factor alpha (TNFα), interferon gamma (IFNγ), and interleukin-6 (IL-6) but increases interleukin-10 (IL-10) and glutathione peroxidase levels. Our findings indicate that intake of the fruits of the Sechium hybrid leads to antioxidant and anti-inflammatory effects in a mouse model. Therefore, these results support the possibility of exploring the clinical effect of this hybrid in humans.

Community Gerontology Model for Healthy Aging Developed in Mexico Framed in Resilience and Generativity.

BACKGROUND: The aims of this paper are to present the evolutionary development of the Community Model of Healthy Aging (CMHA) and to show the main results of the community gerontology studies framed in each of the stages of the CMHA. METHOD: The study employs a qualitative community-based participatory research approach. We also measured several biochemical parameters, social support networks, and indicators of physical and cognitive functioning. RESULTS: We identified three stages in the development of the CMHA. The first stage was informative (CMHA-I, 1994-2000) with more than 70% of the older adults participating in self-care programs for health. The second stage was formative (CMHA-F, 2001-2015) with more than 80% of older adults participating in self-care, mutual aid, and self-management programs. The third stage was emancipatory (CMHA-E, 2016-2018). In this last stage, we added resilience and generativity as basic elements to strengthen and enhance human capacities during aging, and more than 90% of older adults made optimal use of social support networks as a key strategy. CONCLUSION: Our findings suggest that the addition of resilience and generativity in the CMHA contributed to the active participation of older adults in the maintenance of functioning and the prevention and control of diseases linked to aging.

Smells from the desert: Microbial volatiles that affect plant growth and development of native and non-native plant species.

The plant microbiota can affect host fitness via the emission of microbial volatile organic compounds (mVOCs) that influence growth and development. However, evidence of these molecules and their effects in plants from arid ecosystems is limited. We screened the mVOCs produced by 40 core and representative members of the microbiome of agaves and cacti in their interaction with Arabidopsis thaliana and Nicotiana benthamiana. We used SPME-GC-MS to characterize the chemical diversity of mVOCs and tested the effects of selected compounds on growth and development of model and host plants. Our study revealed that approximately 90% of the bacterial strains promoted plant growth both in A. thaliana and N. benthamiana. Bacterial VOCs were mainly composed of esters, alcohols, and S-containing compounds with 25% of them not previously characterized. Remarkably, ethyl isovalerate, isoamyl acetate, 3-methyl-1-butanol, benzyl alcohol, 2-phenylethyl alcohol, and 3-(methylthio)-1-propanol, and some of their mixtures, displayed beneficial effects in A. thaliana and also improved growth and development of Agave tequilana and Agave salmiana in just 60 days. Volatiles produced by bacteria isolated from agaves and cacti are promising molecules for the sustainable production of crops in arid and semi-arid regions.

Functional Signatures of the Epiphytic Prokaryotic Microbiome of Agaves and Cacti.

Microbial symbionts account for survival, development, fitness and evolution of eukaryotic hosts. These microorganisms together with their host form a biological unit known as holobiont. Recent studies have revealed that the holobiont of agaves and cacti comprises a diverse and structured microbiome, which might be important for its adaptation to drylands. Here, we investigated the functional signatures of the prokaryotic communities of the soil and the episphere, that includes the rhizosphere and phyllosphere, associated with the cultivated Agave tequilana and the native and sympatric Agave salmiana, Opuntia robusta and Myrtillocactus geometrizans by mining shotgun metagenomic data. Consistent with previous phylogenetic profiling, we found that Proteobacteria, Actinobacteria and Firmicutes were the main represented phyla in the episphere of agaves and cacti, and that clustering of metagenomes correlated with the plant compartment. In native plants, genes related to aerobic anoxygenic phototrophy and photosynthesis were enriched in the phyllosphere and soil, while genes coding for biofilm formation and quorum sensing were enriched in both epiphytic communities. In the episphere of cultivated A. tequilana fewer genes were identified, but they belonged to similar pathways than those found in native plants. A. tequilana showed a depletion in several genes belonging to carbon metabolism, secondary metabolite biosynthesis and xenobiotic degradation suggesting that its lower microbial diversity might be linked to functional losses. However, this species also showed an enrichment in biofilm and quorum sensing in the epiphytic compartments, and evidence for nitrogen fixation in the rhizosphere. Aerobic anoxygenic phototrophic markers were represented by Rhizobiales (Methylobacterium) and Rhodospirillales (Belnapia) in the phyllosphere, while photosystem genes were widespread in Bacillales and Cyanobacteria. Nitrogen fixation and biofilm formation genes were mostly related to Proteobacteria. These analyses support the idea of niche differentiation in the rhizosphere and phyllosphere of agaves and cacti and shed light on the potential mechanisms by which epiphytic microbial communities survive and colonize plants of arid and semiarid ecosystems. This study establishes a guideline for testing the relevance of the identified functional traits on the microbial community and the plant fitness.

The Biological Significance of Oxidative Stress, Effects of Fruits as Natural Edible Antioxidants.

BACKGROUND: Oxidative stress (OxS) is a biochemical process characterized by an imbalance between the production of reactive species (RS) and antioxidants in favor of the former that subsequently induces the oxidative damage of biomolecules and alters cellular physiology. OxS exerts diverse effects and is associated with the pathophysiology of more than 100 diseases, as well as with the aging process. OxS also plays a role in maintaining the homeostasis of both animal and plant organisms. We analyze the role and mechanisms of the generation of RS and antioxidants both under physiological conditions and during aging and pathological processes. Likewise, the potential of antioxidant agents from the diet is considered, specifically fruits such as chayote. We focus on naringenin, a flavonoid with a high antioxidant capacity. METHOD: We conducted a literature review to present the state of the art of knowledge about the biological significance of oxidative stress and the effect of antioxidants in some edible fruits. CONCLUSIONS: Evidence supports the existence of RS, their physiological roles as well its harmful effects when oxidative stress occurs. In this sense, given the association of oxidative stress with diseases and aging the fruits rich in antioxidants are a feasible alternative to restore de redox balance if necessary.

Efficacy of treadmill exercises on arterial blood oxygenation, oxygen consumption and walking distance in healthy elderly people: a controlled trial.

BACKGROUND: Regular physical exercise and healthy lifestyle can improve aerobic power of the elderly, although lung capacity gradually deteriorates with age. The aims of the study are: a) to evaluate the therapeutic effect of a treadmill exercise program on arterial blood oxygenation (SaO2), maximum oxygen consumption (VO2max) and maximum walking distance (MWD) in healthy elderly people; b) to examine the outcome of the program at a supervised short-term and at an unsupervised long-term. METHODS: A prospective, not-randomized controlled intervention trial (NRCT) was conducted. Eighty participants were allocated into two homogeneous groups (training group, TG, n = 40; control group, CG, n = 40). Each group consisted of 20 men and 20 women. Pre-intervention measures of SaO2, VO2max and MWD were taken of each participant 1-week before the training program to establish the baseline. Also, during the training program, the participants were followed up at the 12, 30 and 48th week. The exercise program consisted of walking on a treadmill with fixed 0 % grade of inclination 3 times weekly for 48 weeks; the first 12 weeks were supervised and the remaining 36 weeks of the program were unsupervised. Participants in the control group were encouraged to walk twice a week during 45 min, and received standard recommendations for proper health. RESULTS: Related to the baseline, the SaO2, VO2max, and MWD is greater in the intervention group at the 12(th) (p <.001), 30(th) (p <.001) and 48(th) week (p <.001). Compared with the control group, there was also a significant improvement of SaO2, VO2max, and MWD valuesin the intervention group (p <.001) at the 12(th) (p <.001), 30(th) (p <.001) and 48(th) week (p <.001). Supervised intervention shows greater improvement of SaO2, VO2max, and MWD values than in the unsupervised one. CONCLUSION: These results show that performing moderate exercise, specifically walking 3 days a week, is highly recommended for healthy older people, improving aerobic power. TRIAL REGISTRATION: Current Controlled Trials ISRCTN12621097 .

Velocity-Based Training of Lower Limb to Improve Absolute and Relative Power Outputs in Concentric Phase of Half-Squat in Soccer Players.

The power production is force-velocity related. We hypothesized that speed-based training of lower limb using half-squat can lead to absolute and relative power improvements in concentric movement with the same external load. One group of 19 soccer players (age = 24.4 years, SD = 3.7 years) participated in a pretest-posttest power training protocol, consistent in 2 training sessions per week during 10 weeks, targeted to work the leg power by performing half-squat with a fixed external load (mean = 71.7, SD = 5.4) at 65% of 1 repetition maximum. Measurements of power (absolute [in watt] and relative [in watt per kilogram]), force (in newton), and velocity (in meter per second) (mean and peak) were made from a concentric movement of a half-squat exercise with a fixed external load. The training protocol increased relative power (mean = 47.5, SD = 47.5, p < 0.001) and absolute power (mean = 169.2, SD = 95.5, p < 0.001). Also, number of repetitions (mean = 2.9, SD = 2.4, p < 0.01), force (mean = 66.6, SD = 36.7, p < 0.001), and velocity (mean = 0.1, SD = 0.1, p < 0.001) were increased. However, only improved velocity was related to the changes in absolute (r = 0.939, p < 0.001) and relative (r = 0.757, p < 0.001) power. The speed-based training combined with moderate to high external load can lead to an improvement of absolute and relative power in concentric phases of half-squat in soccer players. This could be important for improving the performance of the players in the field.

Respuesta fisiológica durante la escalada deportiva / Physiological response during sport climbing

La escalada es una actividad deportiva que consiste en la realización de ascensiones en paredes de fuerte pendiente valiéndose de la fuerza física, la habilidad técnica, la capacidad psicológica y, por lo general, utilizando como única ayuda un calzado especial. La búsqueda de la superación y del rendimiento deportivo, provocan la necesidad de definir y estudiar las características del escalador, así como la mejora de los métodos y técnicas empleados para el entrenamiento. Durante una ascensión, se producen actividades bastantes exigentes, en las que los tiempos de realización oscilan entre 2 y 7 minutos, donde 5/8 del tiempo de trabajo se emplea en posiciones estáticas (descansos, toma de decisiones, aseguramientos, etc.) y el tiempo restante en movimientos de superación. Las sucesivas acciones musculares de sostén (isométricas) y de progresión (isotónicas)en la vertical provocan valores de VO2 en torno a 20-25 ml/kg/min, pudiendo llegar a 30 ml/kg/min, manteniéndose elevados en el tiempo post -ejercicio, existiendo un incremento desproporcionado de la frecuencia cardiaca en relación alVO2. Las pérdidas de resistencia de agarre se han correlacionado con la acumulación de lactato. Los valores alcanzados oscilan entre 2,1 y 6,1 mmol/l, observándose mayores incrementos con la dificultad de la ruta. Parece indicar, que la mayor eliminación de las sustancias metabolizadas, durante las fases de recuperación, aumenta la capacidad de repetir los esfuerzos (AU)

Scaling is a sports activity that consists of the accomplishment of ascents on walls of strong slope using physical force, technical ability, psychological capacity and, generally, using special footwear as the only form of help. The search to overcome and dominate the sport, prompts the need to define and study characteristics of the climber. In doing so, it also provokes the need for improvement in methods and techniques used for training. During an ascent, quite demanding activities take place, in which the time of accomplishment ranges from between 2 to 7 minutes. 5/8 of that working time is spent in static positions (rests, decision making, safety settings, etc.) The remaining time is spent in overcoming movements. The consecutive muscular actions of support (isometric) and progression (isotonic)in the vertical position cause VO2 levels in turn to reach 20-25 ml/kg/min(with the ability to reach30ml/kg/min). These levels remain elevated in post-exercise time. There is an out of proportion increase of heart rate in relation to the VO2. The loss of take hold resistance has been correlated with lactate accumulation. The reached values range from 2.1 and 6.1 mmol/l, observing greater increasing difficulty of the route. This may indicate that the greater clearance of the metabolized substances, during recovery phase, increases the ability of repeating the efforts (AU)

Effects of training exercises for the development of strength and endurance in soccer.

A training program designed to increase strength and aerobic endurance in 1 season was tested on 16 professional soccer players from Spain with a mean age of 28 +/- 3.37 years. The schedule comprised 4 macrocycles of 12 weeks of aerobic endurance and strength training. As much for the strength training as for the aerobic endurance, the program used a sequence of general, special, and specific exercises. Assessments were made with routine tests (i.e., squat jumps [SJs], countermovement jumps [CMJs], and countermovement jumps with arm swing [CMJas]) at the end of each macrocycle, and the Probst test was used to assess aerobic endurance as a function of running speed and distance, at the start and end of the training schedule and at the start of the third macrocycle. Jumps were performed on an infrared platform fitted to the MuscleLab system. The Probst test showed differences between the first evaluation and the second and third evaluations: 3,550 +/- 411.59 m vs. 2,006 +/- 207.20 m (P < 0.01). For 2 of the 3 jumps analyzed, the results were better in the last 2 than in the first 2 evaluations (SJ, 43.13 +/- 3.77 vs. 39.47 +/- 3.4 [P < 0.05]; CMJ, 49.80 +/- 3.77 vs. 46.67 +/- 3.76 [P < 0.05]; CMJas, 56.24 +/- 5.2 vs. 52.98 +/- 4.54 [P > 0.05]). Improvement of aerobic endurance was produced on the first phase of the season as a consequence of the training. To increase strength, it is necessary to augment the number of training sessions of this type. It is convenient to separate aerobic endurance and strength training to create more ample blocks during the last 2 macrocycles.

Influence of vibration training on energy expenditure in active men.

The aim of the present study was to analyze the effect of whole-body vibration on energy expenditure, as well as on exercise intensity, during and immediately after a typical set of exercises for muscle hypertrophy in physically active subjects. Seventeen male university students (mean age 18.3 +/- 0.24 years) volunteered to perform 2 different training exercises: half squat (HS), and half squat with vibration (HSV). Both exercises were performed by all subjects on the vibration platform (with vibration only for HSV), the sequence order being assigned randomly. Energy expenditure (EE), respiratory exchange ratio, perceived exertion (PE), and heart rate were recorded for baseline, exercise, and short-recovery conditions. Training consisted of 5 sets of 10 repetitions of HS and HSV, with a 2-minute recovery interval between sets. Analysis of variance with repeated measurements and Bonferroni correction, as well as effect size were used for statistical calculations. Results indicated that EE and PE were significantly higher in the HSV group, during both exercise and recovery. Heart rate did not differ significantly between groups. Thus, it would appear that HS strength training could be rendered more energy-efficient through the addition of vibration. Moreover, it would be feasible to introduce vibration exercises into regular training programs, particularly those whose key objective is muscle hypertrophy along with fat reduction.

Valoración de la exactitud de predicción del tamaño dental mesiodistal de las tablas de probabilidad de Moyers y las ecuaciones de Tanaka/Johnston en una población mexicana / Assessment of the prediction accuracy of mesiodistal tooth size in the Moyers`s probability tables and the Tanaka/Johnston equations in a Mexican population

La determinación de la discrepancia del tamaño dental-longitud del arco en dentición mixta, requiere de una predicción lo más exacta posible del diámetro mesiodistal de los dientes permanentes no erupcionados como parte esencial de los procedimientos del diagnóstico ortodóntico para instituir un plan de tratamiento coherente. En este sentido los métodos de predicción más comúnmente utilizados en nuestra población son las tablas de Moyers y las ecuaciones de Tanaka/Johnston, sin embargo, tales ecuaciones fueron desarrolladas de estudios en poblaciones caucásicas del Norte de Europa, con lo que su exactitud es cuestionable al ser aplicadas a la población mexicana. El objeto de la presente investigación es determinar la exactitud de predicción de dichos análisis de dentición mixta al ser aplicados a una muestras de 35 adolescentes mexicanos de 12 a 15 años, sin problemas de discrepancia dentoalveolar y ausencia de tratamiento ortodóntico. Las mediciones se realizaron en modelos de yeso e incluyeron el diámetro mesiodistal de los incisivos mandibulares, caninos y premolares maxilares y mandibulares del lado derecho. Se aplicaron los análisis de dentición mixta y con los valores obtenidos se realizó la prueba de ANOVA y análisis de Tuckey; también se aplicó el coeficiente de correlación de Pearson. Los resultados indican que no existen diferencias significativamente estadísticas entre los valores pronosticados y el diámetro mesiodistal actual de caninos y premolares maxilares y mandibulares (P > 0.05)), por lo que se concluye que las ecuaciones de Tanaka/Johnston y las tablas de Moyers en el nivel 75 por ciento son de utilidad clínica al ser aplicadas en nuestra población; asimismo los coeficientes de correlación permiten establecer que las ecuaciones de Tanaka/Johnston tienen mayor exactitud en el pronóstico que las tablas de Moyers en el nivel 75 por ciento (P < 0.001)

Prevalencia de signos y síntomas de los trastornos temporomandibulares en un grupo de adultos mayores / Prevalence of signs and symptoms of temporomandibular joint disorders in a group of older adults

Se realizó un estudio observacional, prospectivo, transversal y descriptivo de 37 ancianos de 60 a 80 años para conocer los signos y síntomas de los trastornos temporomandibulares que se presentan con mayor frecuencia en este grupo etario. Los signos y síntomas que se valoraron fueron: dolor, ruidos articulares, bloqueos, limitación funcional de la apertura mandibular, desgaste dental, pérdida de dientes, dimensión vertical, colapso posterior de la mordida y rehabilitación prostésica, entre otros. El 46 por ciento (n=17) de la población presentó patología dolorosa de la ATM acompañada por los menos con un síntoma , por ej. chasquido, bruxismo o apertura limitada; el 43.2 por ciento (n=16) tiene signos positivos de pérdida de la dimensión vertical; el 81 por ciento (n=30) presenta colapso de la mordida; el 54 por ciento (n=20) de los ancianos que no presentó dolor, está expuesto por lo menos a un factor de riesgo

Prevalencia y factores de riesgo de mordida cruzada posterior en niños de 4-9 años de edad en ciudad Nezahualcóyotl

Introducción. La mordida cruzada posterior es una maloclusión con una prevalencia reportada entre 5 y 27% de los individuos, dependiendo de la edad y características de la población estudiada. Debido a la información existente hasta este momento, donde los factores de riesgo no son específicos; el propósito de este estudio fue conocer la prevalencia de mordida cruzada posterior y los factores de riesgo potenciales que dan lugar a su aparición (erupción ectópica, respiración bucal, succión digital, interferencias oclusales y grupo edad). Material y métodos. Se llevó a cabo un estudio transversal en una población de 1 000 niños de 4 a 9 años de edad en ciudad Nezahualcóyotl, a los cuales se les hizo una exploración intrabucal, valorando la oclusión y análisis funcional. Se efectuó un análisis univariado y de regresión logística con el paquete estadístico SPSS versión 10.0. Resultados. La prevalencia de mordida cruzada posterior fue de 11.3%; dividido en 5.4% con mordida cruzada unilateral; 1.5% mordida cruzada bilateral, 4.8% abarcando un solo diente; por sexo se observó con mayor frecuencia en los niños. Los factores de riesgo que mostraron significancia estadística fueron: erupción ectópica, interferencia oclusal y edad. Con el análisis multivariado se observó que la erupción ectópica y la interferencia oclusal permanecen como los factores de riesgo más importante (P <0.001). Conclusión. La prevalencia de mordida cruzada posterior es alta y la mayor dependencia está dada por erupción ectópica e interferencias oclusales; por lo que es necesario la detección y corrección temprana de cualquier anormalidad en la oclusión dentaria lo que permitirá corregir defectos en el crecimiento dento facial.

Introduction. Posterior cross bite is a malocclusion with a prevalence reported from 5 till 27% of individuals, depending on age and the features of the population studied, due to the existing information at the moment which the risk factors are not specific, the purpose of the present study was to know the prevalence of posterior cross bite and the potential factors of risk which may cause its appearance (ectopic dental eruption, mouth breathing, finger sucking, occlusal disturbances, and age). Material and methods. It was carried out a cross-section study in a population of 1 000 children from 4 till 9 years old in Ciudad Nezahualcoyotl (a suburb of Mexico City), which were undergone to intraoral examination assessing occlusion and functional analysis. Univariate and logistic regression analyses were executed with the statistical software SPSS version 10.0. Results. The prevalence of posterior cross bite was 11.3%, with the following breakdown: 5.4% having unilateral cross bite; 1.5% having bilateral cross bite; 4.8% being affected one tooth only; in the sex structure more prevalence in boys was observed. The factors of risk, which showed statistical significance, were: ectopic eruption, occlusal interference, and group age. Using multivariate analysis, it was observed that ectopic eruption and occlusal interference are the more important risk factors (P < 0.001). Conclusion. Prevalence of posterior cross bite is high and the greatest dependency is produced by ectopic eruption and occlusal interferences, being necessary the early detection and correction of any abnormalities in the tooth occlusion, which would allow correcting disturbances in the dent facial growth.

Prevalencia de caries dental en un grupo de pacientes de la tercera edad / Incidence of dental caries in third age patients

Con el propósito de conocer la prevalencia de caries coronl y radicular se realizó un estudio observacional, prolectivo, transversal y descriptivo en una población geriátrica conformada por 61 ancianos de 60 a 90 años de edad. La valoración clínica de caries coronal se obtuvo con el índice CPOD de Klein y Palmer y la radicular a través del Indice de Caries Radicular de katz (RCI). La caries sigue siendo un problema de salud pública. Para toda la población se encontró un CPOD de 18.3 incrementándose éste conforme avanza la edad pues a los 81 y más años de edad el CPOD fue de 23.0. La distribución porcentual de caries radicular señala un RCI de 34.4 por ciento de afectación en el total de la dentición de esta población, aumentando conforme avanza la edad de los individuos, ya que a la edad de 81 y más años la afectación es del 100 por ciento. La caries coronaria es una enfermedad dentaria primaria, sin embargo, la radicular es secundaria a la exposición bucal del cemento por retracción gingival fisiológica senil o por enfermedad periodontal previa. La caries radicular es la más frecuente en el anciano