Development of a Pseudomonas-based biocontrol consortium with effective root colonization and extended beneficial side effects for plants under high-temperature stress.

The root microbiota plays a crucial role in plant performance. The use of microbial consortia is considered a very useful tool for studying microbial interactions in the rhizosphere of different agricultural crop plants. Thus, a consortium of 3 compatible beneficial rhizospheric Pseudomonas strains previously isolated from the avocado rhizosphere, was constructed. The consortium is composed of two compatible biocontrol P. chlororaphis strains (PCL1601 and PCL1606), and the biocontrol rhizobacterium Pseudomonas alcaligenes AVO110, which are all efficient root colonizers of avocado and tomato plants. These three strains were compatible with each other and reached stable levels both in liquid media and on plant roots. Bacterial strains were fluorescent tagged, and colonization-related traits were analyzed in vitro, revealing formation of mixed biofilm networks without exclusion of any of the strains. Additionally, bacterial colonization patterns compatible with the different strains were observed, with high survival traits on avocado and tomato roots. The bacteria composing the consortium shared the same root habitat and exhibited biocontrol activity against soil-borne fungal pathogens at similar levels to those displayed by the individual strains. As expected, because these strains were isolated from avocado roots, this Pseudomonas-based consortium had more stable bacterial counts on avocado roots than on tomato roots; however, inoculation of tomato roots with this consortium was shown to protect tomato plants under high-temperature stress. The results revealed that this consortium has side beneficial effect for tomato plants under high-temperature stress, thus improving the potential performance of the individual strains. We concluded that this rhizobacterial consortium do not improve the plant protection against soil-borne phytopathogenic fungi displayed by the single strains; however, its inoculation can show an specific improvement of plant performance on a horticultural non-host plant (such as tomato) when the plant was challenged by high temperature stress, thus extending the beneficial role of this bacterial consortium.

Oxidative Stress in Patients with Advanced CKD and Renal Replacement Therapy: The Key Role of Peripheral Blood Leukocytes.

Oxidative stress plays a key role in the pathophysiology of chronic kidney disease (CKD). Most studies have investigated peripheral redox state focus on plasma, but not in different immune cells. Our study analyzed several redox state markers in plasma and isolated peripheral polymorphonuclear (PMNs) and mononuclear (MNs) leukocytes from advanced-CKD patients, also evaluating differences of hemodialysis (HD) and peritoneal dialysis (PD) procedures. Antioxidant (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH)) and oxidant parameters (xanthine oxidase (XO), oxidized glutathione (GSSG), malondialdehyde (MDA)) were assessed in plasma, PMNs and MNs from non-dialysis-dependent-CKD (NDD-CKD), HD and PD patients and healthy controls. Increased oxidative stress and damage were observed in plasma, PMNs and MNs from NDD-CKD, HD and PD patients (increased XO, GSSG and MDA; decreased SOD, CAT, GPX and GSH; altered GSSG/GSH balance). Several oxidative alterations were more exacerbated in PMNs, whereas others were only observed in MNs. Dialysis procedures had a positive effect on preserving the GSSG/GSH balance in PMNs. Interestingly, PD patients showed greater oxidative stress than HD patients, especially in MNs. The assessment of redox state parameters in PMNs and MNs could have potential use as biomarkers of the CKD progression.

A high magnesium concentration in citrate dialysate prevents oxidative stress and damage in human monocytes in vitro.

BACKGROUND: The use of dialysis fluids (DFs) during haemodialysis has been associated with increased oxidative stress and reduced serum magnesium (Mg) levels, contributing to chronic inflammation. Since the role of Mg in modulating immune function and reducing oxidative stress has been demonstrated, the aim of this study was to characterize in vitro whether increasing the Mg concentration in DFs could protect immune cells from oxidative stress and damage. METHODS: The effect of citrate [citrate dialysis fluid (CDF), 1 mM] or acetate [acetate dialysis fluid (ADF), 3 mM] dialysates with low (0.5 mM; routinely used) or high (1 mM, 1.25 mM and 2 mM) Mg concentrations was assessed in THP-1 human monocytes. The levels of reactive oxygen species (ROS), malondialdehyde (MDA) and oxidized/reduced (GSSG/GSH) glutathione were quantified under basal and inflammatory conditions (stimulation with lipopolysaccharide, LPS). RESULTS: The increase of Mg in CDF resulted in a significant reduction of ROS production under basal and inflammatory conditions (extremely marked in 2 mM Mg; P < 0.001). These effects were not observed in ADF. Interestingly, in a dose-dependent manner, high Mg doses in CDF reduced oxidative stress in monocytes under both basal and inflammatory conditions. In fact, 2 mM Mg significantly decreased the levels of GSH, GSSG and MDA and the GSSG/GSH ratio in relation to 0.5 mM Mg. CONCLUSIONS: CDF produces lower oxidative stress than ADF. The increase of Mg content in DFs, especially in CDF, could have a positive and protective effect in reducing oxidative stress and damage in immune cells, especially under inflammatory conditions.

The Immunity Clock.

The immune system has been for long considered a marker of health. The age-related decline in its function results in a greater incidence of infections, autoimmune diseases, and cancer. Nevertheless, it is still not known if immune function can be used to accurately estimate the rate of aging of an individual. A set of 14 immune function variables were measured in 214 healthy individuals ranging from 19 to 88 years old. All immune variables were selected as independent variables for the prediction of age by multiple linear regression. The Immunity Clock was constructed including the following 5 immune variables: natural killer activity, phagocytosis and chemotaxis of neutrophils, and chemotaxis and proliferative capacity of lymphocytes, reaching an adjusted R2 of 80.3% and a standard error of the estimate of 4.74 years. The Immunity Clock was validated in a different group of healthy individuals (N = 106) obtaining a Pearson's correlation coefficient of .898 (p < .001) between chronological age and the age estimated by the Immunity Clock, the ImmunolAge. Moreover, we demonstrate that women with anxiety (N = 10) show a higher ImmunolAge than their chronological age, whereas healthy centenarians (N = 8) show a lower one. In addition, the Immunity Clock provided here proves to be useful for monitoring the effectiveness of a nutritional intervention lasting 1 month, by detecting a diminished ImmunolAge in the same individuals. Further research will be needed to ascertain if the Immunity Clock is a passive marker of the aging process or it plays an active role in it.

Ontogeny of leukocyte profiles in a wild altricial passerine.

Ecophysiological studies have highlighted the relevance of the avian immune system in individual fitness prospects in the wild. However, studies on the ontogeny of avian immunity are scarce. We analyse age-related changes in the cellular constitutive immunity throughout nestling development, as well as its relationship with sex and brood size. We found that cellular constitutive immunity could be affected by age, sex, brood size, or daily rhythm. Early-stage nestlings relied more on cells of the innate immunity rather than on cells linked to the adaptive immune system. Cellular immunity may not be fully mature in fledglings, as reflected by differences in phagocytic cell counts with regard to adults. Beyond the age-dependent effects, agranulocyte cell counts were affected by sibling competition while granulocyte cell counts showed a daily rhythm. We also show that the heterophil to lymphocyte ratio was negatively related to body weight when nestlings become more independent. Our study contributes knowledge to the fields of developmental immunology and ecological immunology based on essential components of the cellular immune system.

Soil Application of a Formulated Biocontrol Rhizobacterium, Pseudomonas chlororaphis PCL1606, Induces Soil Suppressiveness by Impacting Specific Microbial Communities.

Biocontrol bacteria can be used for plant protection against some plant diseases. Pseudomonas chlororaphis PCL1606 (PcPCL1606) is a model bacterium isolated from the avocado rhizosphere with strong antifungal antagonism mediated by the production of 2-hexyl, 5-propil resorcinol (HPR). Additionally, PcPCL1606 has biological control against different soil-borne fungal pathogens, including the causal agent of the white root rot of many woody crops and avocado in the Mediterranean area, Rosellinia necatrix. The objective of this study was to assess whether the semicommercial application of PcPCL1606 to soil can potentially affect avocado soil and rhizosphere microbial communities and their activities in natural conditions and under R. necatrix infection. To test the putative effects of PcPCL1606 on soil eukaryotic and prokaryotic communities, a formulated PcPCL1606 was prepared and applied to the soil of avocado plants growing in mesocosm experiments, and the communities were analyzed by using 16S/ITS metagenomics. PcPCL1606 survived until the end of the experiments. The effect of PcPCL1606 application on prokaryotic communities in soil and rhizosphere samples from natural soil was not detectable, and very minor changes were observed in eukaryotic communities. In the infested soils, the presence of R. necatrix strongly impacted the soil and rhizosphere microbial communities. However, after PcPCL1606 was applied to soil infested with R. necatrix, the prokaryotic community reacted by increasing the relative abundance of few families with protective features against fungal soilborne pathogens and organic matter decomposition (Chitinophagaceae, Cytophagaceae), but no new prokaryotic families were detected. The treatment of PcPCL1606 impacted the fungal profile, which strongly reduced the presence of R. necatrix in avocado soil and rhizosphere, minimizing its effect on the rest of the microbial communities. The bacterial treatment of formulated PcPCL1606 on avocado soils infested with R. necatrix resulted in biological control of the pathogen. This suppressiveness phenotype was analyzed, and PcPCL1606 has a key role in suppressiveness induction; in addition, this phenotype was strongly dependent on the production of HPR.

Increasing the Magnesium Concentration in Various Dialysate Solutions Differentially Modulates Oxidative Stress in a Human Monocyte Cell Line.

Oxidative stress is exacerbated in hemodialysis patients by several factors, including the uremic environment and the use of dialysis fluids (DFs). Since magnesium (Mg) plays a key role in modulating immune function and in reducing oxidative stress, we aimed to evaluate whether increasing the Mg concentration in different DFs could protect against oxidative stress in immunocompetent cells in vitro. Effect of ADF (acetate 3 mM), CDF (citrate 1 mM), and ACDF (citrate 0.8 mM + acetate 0.3 mM) dialysates with Mg at standard (0.5 mM) or higher (1, 1.25, and 2 mM) concentrations were assessed in THP-1 monocyte cultures. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were quantified under basal and uremic conditions (indoxyl sulfate (IS) treatment). Under uremic conditions, the three DFs with 0.5 mM Mg promoted higher ROS production and lipid damage than the control solution. However, CDF and ACDF induced lower levels of ROS and MDA, compared to that induced by ADF. High Mg concentration (1.25 and/or 2 mM) in CDF and ACDF protected against oxidative stress, indicated by reduced ROS and MDA levels compared to respective DFs with standard concentration of Mg. Increasing Mg concentrations in ADF promoted high ROS production and MDA content. Thus, an increase in Mg content in DFs has differential effects on the oxidative stress in IS-treated THP-1 cells depending on the dialysate used.

Mechanisms of Cardiovascular Disorders in Patients With Chronic Kidney Disease: A Process Related to Accelerated Senescence.

Cardiovascular diseases (CVDs), especially those involving a systemic inflammatory process such as atherosclerosis, remain the leading cause of morbidity and mortality in patients with chronic kidney disease (CKD). CKD is a systemic condition affecting approximately 10% of the general population. The prevalence of CKD has increased over the past decades because of the aging of the population worldwide. Indeed, CVDs in patients with CKD constitute a premature form of CVD observed in the general population. Multiple studies indicate that patients with renal disease undergo accelerated aging, which precipitates the appearance of pathologies, including CVDs, usually associated with advanced age. In this review, we discuss several aspects that characterize CKD-associated CVDs, such as etiopathogenic elements that CKD patients share with the general population, changes in the cellular balance of reactive oxygen species (ROS), and the associated process of cellular senescence. Uremia-associated aging is linked with numerous changes at the cellular and molecular level. These changes are similar to those observed in the normal process of physiologic aging. We also discuss new perspectives in the study of CKD-associated CVDs and epigenetic alterations in intercellular signaling, mediated by microRNAs and/or extracellular vesicles (EVs), which promote vascular damage and subsequent development of CVD. Understanding the processes and factors involved in accelerated senescence and other abnormal intercellular signaling will identify new therapeutic targets and lead to improved methods of diagnosis and monitoring for patients with CKD-associated CVDs.

Redox Parameters as Markers of the Rate of Aging and Predictors of Life Span.

Oxidative stress has been reported to increase with aging, and although several age-related changes in redox parameters have been described, none of them have been verified as markers of the rate of aging and life span. Therefore, antioxidant (catalase, glutathione peroxidase, reductase activities, and reduced glutathione) and oxidant (oxidized glutathione, basal superoxide anion, and malondialdehyde concentrations) parameters were studied in whole blood cells from humans divided into different age groups (adult, mature, older adult, nonagenarian, and centenarian) in a cross-sectional study. Moreover, the same parameters were investigated in peritoneal leukocytes of mice at the analogous human ages (adult, mature, old, very old, and long-lived) in a longitudinal study as well as in adult prematurely aging mice. The results reveal that the age-related alterations of these markers are similar in humans and mice, with decreased antioxidants and increased oxidants in old participants, whereas long-lived individuals show similar values to those in adults. In addition, adult prematurely aging mice showed similar values to those in chronologically old mice and had a shorter life span than nonprematurely aging mice. Thus, these parameters could be proposed as markers of the rate of aging and used to ascertain biological age in humans.

Immune Function, Oxidative, and Inflammatory Markers in Centenarians as Potential Predictors of Survival and Indicators of Recovery After Hospital Admission.

Several parameters of immune function, oxidative, and inflammatory stresses have been proposed as markers of health and predictors of longevity and mortality. However, it is unknown if any of these parameters can be used as predictors of survival in centenarians. Therefore, in a group of 27 centenarians, at the time of admission to the Clinical Hospital of Madrid, a series of immune function, antioxidant, oxidant, and inflammatory parameters were studied. Some centenarians survived and others did not, thus establishing two groups, "survivors" (n = 9) and "nonsurvivors" (n = 18). The results show that surviving centenarians display higher neutrophil chemotaxis and microbicidal capacity, natural killer activity, lymphoproliferation, glutathione reductase activity, and basal interleukin-10 release. Moreover, lower neutrophil and lymphocyte adherence, superoxide anion and malondialdehyde concentrations, and basal release of tumor necrosis factor α are also reported. The odds ratios for survival for these parameters were also calculated, with the highest odds ratios being the lymphoproliferative capacity and the ex vivo basal and stimulated release of interleukin-6 from mononuclear cells (odds ratio = 136.00). Therefore, these parameters have the potential to be used in the clinical setting as predictors of survival in centenarians. In the survivors group, the same parameters were also analyzed after 3 months. Because survivors showed an increase in neutrophil and lymphocyte chemotaxis capacity during the recovery period, reaching similar values to those observed in healthy centenarians, these parameters could be proposed as indicators of recovery.

High perceived stress in women is linked to oxidation, inflammation and immunosenescence.

Chronic stress situations lead to an impairment of immune response and higher oxidative and inflammatory stress, which are important underlying mechanisms of the ageing process. However, given that the physiological stress response depends on the subjective appraisal of a given stressor, the aim of the study was to investigate the effect that different degrees of perceived stress have, regardless of their type, on immune functions, oxidative and inflammatory stress and ageing rate of women (30-50 years old). For that purpose, a group of 49 women was classified, according to their scores obtained in the perceived stress scale (PSS), into low (n = 23), moderate (n = 14) and high (n = 12) degree of perceived stress. The immune functions studied were: neutrophil and lymphocyte chemotaxis, neutrophil phagocytic capacity, natural killer activity, lymphoproliferation and LPS-stimulated cytokine release. Basal cytokine release was studied as an inflammatory stress marker. Antioxidant (superoxide dismutase, glutathione peroxidase and reductase activities, and reduced glutathione) and oxidant compounds (oxidized glutathione and malondialdehyde) were also investigated in whole blood as markers of oxidative stress. The results show that, in general, women with a moderate or high degree of perceived stress have a worse immune functionality and higher oxidative and inflammatory stress compared to women with low stress perception. In addition, a positive correlation was found between PSS scores and the biological age of each woman (P ≤ 0.001). In conclusion, high levels of perceived stress in women are associated with a higher oxidative and inflammatory stress and immunosenescence, which seem to accelerate their ageing rate.

When will my mouse die? Life span prediction based on immune function, redox and behavioural parameters in female mice at the adult age.

The identification of predictive markers of life span would help to unravel the underlying mechanisms influencing ageing and longevity. For this aim, 30 variables including immune functions, inflammatory-oxidative stress state and behavioural characteristics were investigated in ICR-CD1 female mice at the adult age (N = 38). Mice were monitored individually until they died and individual life spans were registered. Multiple linear regression was carried out to construct an Immunity model (adjusted R2 = 75.8%) comprising Macrophage chemotaxis and phagocytosis and Lymphoproliferation capacity, a Redox model (adjusted R2 = 84.4%) involving Reduced Glutathione and Malondialdehyde concentrations and Glutathione Peroxidase activity and a Behavioural model (adjusted R2 = 79.8%) comprising Internal Locomotion and Time spent in open arms indices. In addition, a Combined model (adjusted R2 = 92.4%) and an Immunity-Redox model (adjusted R2 = 88.7%) were also constructed by combining the above-mentioned selected variables. The models were also cross-validated using two different sets of female mice (N = 30; N = 40). Correlation between predicted and observed life span was 0.849 (P < 0.000) for the Immunity model, 0.691 (P < 0.000) for the Redox, 0.662 (P < 0.000) for the Behavioural and 0.840 (P < 0.000) for the Immunity-Redox model. Thus, these results provide a new perspective on the use of immune function, redox and behavioural markers as prognostic tools in ageing research.

Function, Oxidative, and Inflammatory Stress Parameters in Immune Cells as Predictive Markers of Lifespan throughout Aging.

According to the oxidative-inflammatory theory of aging, there is a link between the function, the oxidative-inflammatory stress state of immune cells, and longevity. However, it is unknown which immune cell parameters can predict lifespan and if there would be any changes in this prediction, depending on the age of the subject. Therefore, a longitudinal study in mice was performed analysing immune function (chemotaxis of macrophages and lymphocytes, phagocytosis of macrophages, natural killer (NK) activity, and lymphoproliferation capacity), antioxidant (catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities as well as reduced glutathione (GSH) concentrations), oxidant (oxidized glutathione (GSSG), superoxide anion, and malondialdehyde (MDA) concentrations), and inflammation-related markers (basal release of IL-1ß, IL-6, TNF-α, and IL-10) in peritoneal leukocytes from mice at the adult, mature, old, very old, and long-lived ages (40, 56, 72, 96, and 120 ± 4 weeks of age, respectively). The results reveal that some of the investigated parameters are determinants of longevity at the adult age (lymphoproliferative capacity, lymphocyte chemotaxis, macrophage chemotaxis and phagocytosis, GPx activity, and GSH, MDA, IL-6, TNF-α, and IL-10 concentrations), and therefore, they could be proposed as markers of the rate of aging. However, other parameters are predictive of extreme longevity only at the very old age (NK activity, CAT and GR activities, and IL-6 and IL-1ß concentrations), and as such, they could reflect some of the adaptive mechanisms underlying the achievement of high longevity. Nevertheless, although preliminary, the results of the present study provide a new perspective on the use of function, redox, and inflammatory parameters in immune cells as prognostic tools in aging research and represent a novel benchmark for future work aimed at prediction of lifespan.

Altered Redox State in Whole Blood Cells from Patients with Mild Cognitive Impairment and Alzheimer's Disease.

Oxidative stress plays an essential and early role in the pathophysiology of Alzheimer's disease (AD). Alterations in the redox state in AD and in mild cognitive impairment (MCI) patients appear in the brain and at peripheral level. Given that it is easier to study the latter, most of the research has been focused on plasma. However, the analysis of redox parameters in whole blood cells (including erythrocytes and leukocytes) has not really been investigated. Moreover, the association of these parameters with Mini-Mental State Examination (MMSE) clinical scores, has scarcely been studied. Therefore, the aim of the present work was to analyze several redox markers in whole blood cells from male and female MCI and AD patients. Antioxidant (superoxide dismutase, catalase (CAT), glutathione peroxidase (GPx), and reductase (GR) activities, and reduced glutathione (GSH) concentration) together with oxidant parameters (oxidized glutathione (GSSG) and thiobarbituric acid-reactive substances (TBARS)) were investigated using MCI and AD (10 women and 10 men in each group) and their age-matched control groups (15 women and 15 men). The results show an altered redox state in whole blood cells from AD patients (higher CAT, GSSG/GSH, TBARS and lower GPx, GR, GSH). Some of these redox parameters are already affected in MCI patients (higher TBARS and lower GPx and GR activities) in both sexes and, consequently, they could be used as markers of prodromal AD. Since GR, GSH, GSSG, and GSSG/GSH were found to be associated with MMSE scores, they seem to be useful clinically to monitor cognitive decline in AD progression.

Fitness Features Involved in the Biocontrol Interaction of Pseudomonas chlororaphis With Host Plants: The Case Study of PcPCL1606.

The goal of this mini review is to summarize the relevant contribution of some beneficial traits to the behavior of the species Pseudomonas chlororaphis, and using that information, to give a practical point of view using the model biocontrol strain P. chlororaphis PCL1606 (PcPCL1606). Among the group of plant-beneficial rhizobacteria, P. chlororaphis has emerged as a plant- and soil-related bacterium that is mainly known because of its biological control of phytopathogenic fungi. Many traits have been reported to be crucial during the multitrophic interaction involving the plant, the fungal pathogen and the soil environment. To explore the different biocontrol-related traits, the biocontrol rhizobacterium PcPCL1606 has been used as a model in recent studies. This bacterium is antagonistic to many phytopathogenic fungi and displays effective biocontrol against fungal phytopathogens. Antagonistic and biocontrol activities are directly related to the production of the compound 2-hexyl, 5-propyl resorcinol (HPR), despite the production of other antifungal compounds. Furthermore, PcPCL1606 has displayed additional traits regarding its fitness in soil and plant root environments such as soil survival, efficient plant root colonization, cell-to-cell interaction or promotion of plant growth.

Lymphoproliferation Impairment and Oxidative Stress in Blood Cells from Early Parkinson's Disease Patients.

In Parkinson's Disease (PD), the peripheral changes in the functional capacity and redox state of immune cells has been scarcely investigated, especially in the early PD stages. Aging is a risk factor for PD, and the age-related impairment of the immune system, based on a chronic-oxidative stress situation, is involved in the rate of aging. We analyzed several functions in isolated peripheral blood neutrophils and mononuclear cells from PD stage 2 patients, and compared the results to those in healthy elderly and adult controls. Several oxidative stress and damage parameters were studied in whole blood cells. The results showed an impairment of the lymphoproliferative response in stimulated conditions in the PD patients compared with age-matched controls, who also showed typical immunosenescence in comparison with adult individuals. Higher oxidative stress and damage were observed in whole blood cells from PD patients (lower glutathione peroxidase activity, and higher oxidized glutathione and malondialdehyde contents). Our results suggest an accelerated immunosenescence in PD stage 2, and that several of the parameters studied could be appropriate peripheral biomarkers in the early stages of PD.

Protein Carbamylation: A Marker Reflecting Increased Age-Related Cell Oxidation.

Carbamylation is a post-translational modification of proteins that may partake in the oxidative stress-associated cell damage, and its increment has been recently proposed as a "hallmark of aging". The molecular mechanisms associated with aging are related to an increased release of free radicals. We have studied whether carbamylated proteins from the peripheral blood of healthy subjects are related to oxidative damage and aging, taking into account the gender and the immune profile of the subjects. The study was performed in healthy human volunteers. The detection of protein carbamylation and malondialdehyde (MDA) levels was evaluated using commercial kits. The immune profile was calculated using parameters of immune cell function. The results show that the individuals from the elderly group (60⁻79 years old) have increased carbamylated protein and MDA levels. When considered by gender, only men between 60 and 79 years old showed significantly increased carbamylated proteins and MDA levels. When those subjects were classified by their immune profile, the carbamylated protein levels were higher in those with an older immune profile. In conclusion, the carbamylation of proteins in peripheral blood is related to age-associated oxidative damage and to an aging functional immunological signature. Our results suggest that carbamylated proteins may play an important role at the cellular level in the aging process.

Frailty Quantified by the "Valencia Score" as a Potential Predictor of Lifespan in Mice.

The development of frailty scores suitable for mice and which resemble those used in the clinical scenario is of great importance to understand human frailty. The aim of the study was to determine an individual frailty score for each mouse at different ages and analyze the association between the frailty score and its lifespan. For this purpose, the "Valencia Score" for frailty was used. Thus, a longitudinal study in mice was performed analyzing weight loss, running time and speed, grip strength and motor coordination at the late-adult, mature and old ages (40, 56 and 80 weeks old, respectively). These parameters are equivalent to unintentional weight loss, poor endurance, slowness, weakness, and low activity level, respectively, in humans. A cut-off point was used to identify frail mice for each criterion. All the measurements were also performed on chronologically adult prematurely aging mice. The results show that by using the "Valencia Score" for frailty a prematurely aged phenotype can be identified even during the adulthood of animals. This opens up the possibility of carrying out preventive long-term interventions. Moreover, the individual frailty score of a given mouse at the late-adult, mature and old ages is shown to be a relevant predictor of its lifespan.

An Appropriate Modulation of Lymphoproliferative Response and Cytokine Release as Possible Contributors to Longevity.

The decrease in the proliferative response of lymphocytes is one of the most evident among the age-related changes of the immune system. This has been linked to a higher risk of mortality in both humans and experimental animals. However, long-lived individuals, in spite of optimally maintaining most of the functions of the immune system, also seem to show an impaired proliferative response. Thus, it was hypothesized that these individuals may have distinct evolution times in this proliferation and a different modulatory capacity through their cytokine release profiles. An individualized longitudinal study was performed on female ICR-CD1 mice, starting at the adult age (40 weeks old), analyzing the proliferation of peritoneal leukocytes at different ages in both basal conditions and in the presence of the mitogen Concanavalin A, for 4, 24 and 48 h of culture. The cytokine secretions (IL-2, IL-17, IL-1ß, IL-6, TNF-α and IL-10) in the same cultures were also studied. Long-lived mice show a high proliferative capacity after short incubation times and, despite experiencing a functional decline when they are old, are able to compensate this decrease with an appropriate modulation of the lymphoproliferative response and cytokine release. This could explain their elevated resistance to infections and high longevity.

Impact of motility and chemotaxis features of the rhizobacterium Pseudomonas chlororaphis PCL1606 on its biocontrol of avocado white root rot.

The biocontrol rhizobacterium Pseudomonas chlororaphis PCL1606 has the ability to protect avocado plants against white root rot produced by the phytopathogenic fungus Rosellinia necatrix. Moreover, PCL1606 displayed direct interactions with avocado roots and the pathogenic fungus. Thus, nonmotile (flgK mutant) and non-chemotactic (cheA mutant) derivatives of PCL1606 were constructed to emphasize the importance of motility and chemotaxis in the biological behaviour of PCL1606 during the biocontrol interaction. Plate chemotaxis assay showed that PCL1606 was attracted to the single compounds tested, such as glucose, glutamate, succinate, aspartate and malate, but no chemotaxis was observed to avocado or R. necatrix exudates. Using the more sensitive capillary assay, it was reported that smaller concentrations (1 mM) of single compounds elicited high chemotactic responses, and strong attraction was confirmed to avocado and R. necatrix exudates. Finally, biocontrol experiments revealed that the cheA and fglK derivative mutants reduced root protection against R. necatrix, suggesting an important role for these biological traits in biocontrol by P. chlororaphis PCL1606. [Int Microbiol 20(2):94-104 (2017)].