The impact of filamentous plant pathogens on the host microbiota.

When a pathogen invades a plant, it encounters a diverse microbiota with some members contributing to the health and growth of the plant host. So far, the relevance of interactions between pathogens and the plant microbiota are poorly understood; however, new lines of evidence suggest that pathogens play an important role in shaping the microbiome of their host during invasion. This review aims to summarize recent findings that document changes in microbial community composition during the invasion of filamentous pathogens in plant tissues. We explore the known mechanisms of interaction between plant pathogens and the host microbiota that underlie these changes, particularly the pathogen-encoded traits that are produced to target specific microbes. Moreover, we discuss the limitations of current strategies and shed light on new perspectives to study the complex interaction networks between filamentous pathogens and the plant microbiome.

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.

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.

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.

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)