National University of Tucuman
  • San Miguel de Tucumán, Tucumán, Argentina
Recent publications
Landscapes dominated by conventional agriculture reduce and simplify natural habitats, with negative consequences for ecosystem regulating services. We examined differences in structure and composition of bee communities across biotic and abiotic gradients to investigate how these communities respond to land-use changes associated with agriculture. Studies like ours which evaluates the relative effect of different components of spatial heterogeneity remain uncommon and are important to conserve pollinator fauna. The diversity of floral resources and habitat richness including the configuration and composition of landscape heterogeneity have been shown to influence the diversity of wild bees on a landscape scale. In this study, we examined how wild bee communities respond to landscape heterogeneity in a semi-arid productive region of Entre Ríos Argentina. We modeled the effect of landscape heterogeneity on wild bee community abundance, species richness, and Chao-1 diversity. We sampled bees using pan traps in four common land-uses in the region (forest plantations, pasture/croplands, mixed use areas and native espinal savanna) for five months in the spring-summer of 2014–2015. We identified 96 bee species among 3407 bees collected in the four habitat types. Pasture/croplands along with native espinal savanna supported the highest abundance, richness, and diversity of bees. Species composition of wild bee communities differed between land uses, with numerous species unique to each land use. Across all land use types, diversity of flower resources consistently supported more abundant and diverse wild bee communities. The richness of habitats along with the diversity of floral resources acted synergistically over wild bee communities. Our findings further clarify the relationship between land-use and wild bee communities, which provide valuable pollination services to crops and native plants. Continued expansion of large-scale monoculture forest plantations will likely come at the expense of the native floral resources, which are a key component to support regional bee species richness. Promoting landscapes with a diversity of crops and flower resources are important for the conservation of pollinators that are key for the functioning of ecosystems.
Biopurification systems (BPS) or biobeds are bioprophylaxis systems to prevent pesticide point-source contamination, whose efficiency relies mostly on the pesticide removal capacity of the biomixture, the majority component of a BPS. The adaptation of the components of the biomixtures to local availabilities is a key aspect to ensure the sustainability of the system. In this work, the removal of atrazine (ATZ) was evaluated in biomixtures formulated with three sugarcane by-products as alternative lignocellulosic substrates. Based on the capacity of actinobacteria to tolerate and degrade diverse pesticides, the effect of biomixtures bioaugmentation with actinobacteria was evaluated as a strategy to enhance the depuration capacity of biobeds. Also, the effect of ATZ and/or the bioaugmentation on microbial developments and enzymatic activities were studied. The biomixtures formulated with bagasse, filter cake, or harvest residue, reached pesticide removal values of 37–41% at 28 d of incubation, with t1/2 between 37.9 ± 0.4 d and 52.3 ± 0.4 d. The bioaugmentation with Streptomyces sp. M7 accelerated the dissipation of the pesticide in the biomixtures, reducing ATZ t1/2 3-fold regarding the controls, and achieving up to 72% of ATZ removal. Atrazine did not exert a clear effect on microbial developments, although most of the microbial counts were less in the contaminated biomixtures at the end of the assay. The bioaugmentation improved the development of the microbiota in general, specially actinobacteria and fungi, regarding the non-bioaugmented systems. The inoculation with Streptomyces sp. M7 enhanced acid phosphatase activity and/or reversed a possible effect of the pesticide over this enzymatic activity.
Modern non-lithifying stromatolites on the shore of the volcanic lake Socompa (SST) in the Puna are affected by several extreme conditions. The present study assesses for the first time light utilization and functional metabolic stratification of SST on a millimeter scale through shotgun metagenomics. In addition, a scanning-electron-microscopy approach was used to explore the community. The analysis on SST unveiled the profile of a photosynthetic mat, with cyanobacteria not directly exposed to light, but placed just below a high-UV-resistant community. Calvin–Benson and 3-hydroxypropinate cycles for carbon fixation were abundant in upper, oxic layers, while the Wood–Ljungdahl pathway was dominant in the deeper anoxic strata. The high abundance of genes for UV-screening and oxidant-quenching pigments and CPF (photoreactivation) in the UV-stressed layers could indicate that the zone itself works as a UV shield. There is a remarkable density of sequences associated with photoreceptors in the first two layers. Also, genetic evidence of photosynthesis split in eukaryotic (layer 1) and prokaryotic (layer 2). Photoheterotrophic bacteria, aerobic photoautotrophic bacteria, and anaerobic photoautotrophic bacteria coexist by selectively absorbing different parts of the light spectrum (blue, red, and IR respectively) at different positions of the mat. Genes for oxygen, nitrogen, and sulfur metabolism account for the microelectrode chemical data and pigment measurements performed in previous publications. We also provide here an explanation for the vertical microbial mobility within the SST described previously. Finally, our study points to SST as ideal modern analogues of ancient ST.
Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)-even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth's surface.
The synthetic protocol and solid state characterization of two new coumarin‐pyrazolylthiazole hybrids (1‐2) are detailed in this manuscript. Synthesized compounds were characterized applying nuclear magnetic resonance, Fourier‐transform infrared spectroscopy and single‐crystal X‐ray diffraction techniques. A detailed structural analysis of 3‐(2‐(5‐(4‐bromophenyl)‐3‐(4‐fluorophenyl)‐4,5‐dihydropyrazol‐1‐yl)thiazol‐4‐yl)‐2H‐chromen‐2‐one (1) and 3‐(2‐(3,5‐bis(4‐bromophenyl)‐4,5‐dihydropyrazol‐1‐yl)thiazol‐4‐yl)‐2H‐chromen‐2‐one (2) is reported along with a detailed description of the noncovalent interactions and their evaluation using Hirshfeld surface analysis, emphasizing the structure‐directing role of C−H⋅⋅⋅O, Br⋅⋅⋅π and π–π interactions. Finally, DFT energetics, molecular electrostatic potential (MEP), quantum theory of “atoms‐in‐molecules” (QTAIM) and noncovalent interaction plot (NCIplot) index computations have been used to further investigate the relative importance of two different π‐stacking complexes observed in the solid state of both compounds, which are recurrent binding motifs in their crystal packing. This manuscript reports the synthesis, X‐ray characterization and theoretical study of dihalophenyl substituted chromenones focusing on the formation of energetically significant antiparallel π‐stacking interactions.
In a previous work, we demonstrated that nasally administered Corynebacterium pseudodiphtheriticum 090104 beneficially modulated the respiratory innate immune response and improved the protection against Respiratory Syncytial Virus and Streptococcus pneumoniae in mice. In this work, we aimed to evaluate whether the immunomodulatory 090104 strain was able to enhance the resistance against the respiratory infection induced by hypermucoviscous carbapenemase-producing (KPC-2) Klebsiella pneumoniae strains belonging to the sequence type (ST) 25. The nasal treatment of mice with C. pseudodiphtheriticum 090104 before the challenge with multiresistant K. pneumoniae ST25 strains significantly reduced lung bacterial cell counts and lung tissue damage. The protective effect of the 090104 strain was related to its ability to regulate the respiratory innate immune response triggered by K. pneumoniae challenge. C. pseudifteriticum 090104 differentially modulated the recruitment of leukocytes into the lung and the production of TNF-α, IFN-γ and IL-10 levels in the respiratory tract and serum. Our results make an advance in the positioning of C. pseudodiphtheriticum 090104 as a next-generation probiotic for the respiratory tract and encourage further research of this bacterium as a promising alternative to develop non-antibiotic therapeutical approaches to enhance the prevention of infections produced by microorganisms with multiple resistance to antimicrobials such as KPC-2-producing hypermucoviscous K. pneumoniae strains belonging to ST25.
Cline variation in ecoregion transition zones can provide strong evidence for adaptation to different environments. We describe the geographical gradations of phenotypes and genetic variation between two rodent species across an environmental gradient in northwestern Argentina. We applied an integrative analysis of the genetic (mtDNA) and phenotypic (skull morphometrics and pelage colorimetrics) variation in Graomys griseoflavus and G. chacoensis, at the margin of their ranges along a local transect between the Chaco and the Monte Desert ecoregions. We aimed to test the hypothesis that phenotypic clines between species corresponds with the transition between these two ecoregions. Molecular identification based on 777 bp of the mitochondrial cyt b evidenced that both species did not occur in syntopy and corroborated a marked genetic differentiation. Subtle species differences were evident in both skull morphometrics and pelage colorimetrics. Generalized additive models of phenotypic traits suggested an ecological and evolutionary interaction between species and their environment. The tympanic bullae traits showed a significant cline variation across the transition zone, both being greater in the specimens from the Monte Desert ecoregion. The phenotypic shift along the transect showed disparate patterns not always coincident with the transition between ecoregions. These patterns could arise by means of selection (or phenotypic plasticity) due to local conditions favoring different traits in populations inhabiting distinct environments.
Modern microbialites in Argentina’s Puna (Central Andes) are considered a reliable tool for understanding the evolution of early life on our planet and developing strategies for detecting life on Mars. The morphological, structural and geochemical variations in these deposits, together with their distribution and architecture, are some of the most important parameters for understanding and characterising them. However, the lack of appropriate cartography and/or the high price to access it, added to the complex geological and geomorphological context in this region, complicate a traditional mapping on a good scale of detail. This paper presents a GIS-based methodology for a detailed mapping and architectural modeling of Las Quínoas microbialitic deposit (Holocene). To meet this objective, the geoprocessing of the information obtained from drone surveys, fieldwork and laboratory work, is carried out using ArcGIS software. The result is a high-resolution reconstruction of the deposit architecture, together with several thematic maps that represent the variation of the morphological, structural and geochemical characteristics of the oncoids (microbialites) with respect to depth and their position in the water body. From an integral point of view, this work provides a new methodological approach for microbialites mapping and improves the survey strategies in Central Andes.
Background Recently, it was defined that the sellar barrier entity could be identified as a predictor of cerebrospinal fluid (CSF) intraoperative leakage. The aim of this study is to validate the application of the sellar barrier concept for predicting intraoperative CSF leak in endoscopic endonasal surgery for pituitary adenomas with a machine learning approach. Methods We conducted a prospective cohort study, from June 2019 to September 2020: data from 155 patients with pituitary subdiaphragmatic adenoma operated through endoscopic approach at the Division of Neurosurgery, Università degli Studi di Napoli “Federico II,” were included. Preoperative magnetic resonance images (MRI) and intraoperative findings were analyzed. After processing patient data, the experiment was conducted as a novelty detection problem, splitting outliers (i.e., patients with intraoperative fistula, n = 11/155) and inliers into separate datasets, the latter further separated into training ( n = 115/144) and inlier test ( n = 29/144) datasets. The machine learning analysis was performed using different novelty detection algorithms [isolation forest, local outlier factor, one-class support vector machine (oSVM)], whose performance was assessed separately and as an ensemble on the inlier and outlier test sets. Results According to the type of sellar barrier, patients were classified into two groups, i.e., strong and weak barrier; a third category of mixed barrier was defined when a case was neither weak nor strong. Significant differences between the three datasets were found for Knosp classification score ( p = 0.0015), MRI barrier: strong ( p = 1.405 × 10 ⁻⁶ ), MRI barrier: weak ( p = 4.487 × 10 ⁻⁸ ), intraoperative barrier: strong ( p = 2.788 × 10 ⁻⁷ ), and intraoperative barrier: weak ( p = 2.191 × 10 ⁻¹⁰ ). We recorded 11 cases of intraoperative leakage that occurred in the majority of patients presenting a weak sellar barrier ( p = 4.487 × 10 ⁻⁸ ) at preoperative MRI. Accuracy, sensitivity, and specificity for outlier detection were 0.70, 0.64, and 0.72 for IF; 0.85, 0.45, and 1.00 for LOF; 0.83, 0.64, and 0.90 for oSVM; and 0.83, 0.55, and 0.93 for the ensemble, respectively. Conclusions There is a true correlation between the type of sellar barrier at MRI and its in vivo features as observed during endoscopic endonasal surgery. The novelty detection models highlighted differences between patients who developed an intraoperative CSF leak and those who did not.
During the Formative period by the Late-Holocene (ca. 3000–1500 BP), semi-sedentary and sedentary human occupations had emerged in the oases, salares, and riverine systems in the central depression (2400–1000 masl) of the Atacama Desert, northern Chile (19–25°S). This hyperarid core was marginally occupied during the post-Pleistocene and middle Holocene droughts. Settlement on these lower belts was accompanied by a rise in humidity, the introduction of Andean crops, flourishment of Prosopis spp. (algarrobo) forests, and increasing integration of domestic camelid caravans. Here, we explore lowland husbandry within risk-spreading strategies, focusing on silvopastoralism and endozoochory between camelids and algarrobos. Analysis of camelid coprolites from seven archeological sites located in the Pampa del Tamarugal, Loa River, and Salar de Atacama found intense grinding from camelid chewing and indicated a ruminal digestive system. Abundant macro and microremains in the form of tissues, phytoliths, crystals, cell structures, and others, were identified as Prosopis, Atriplex, Schoenoplectus, Distichlis, and Phragmites. We conclude that camelids were foraging for Prosopis, although the rather low number of entire seeds preserved in the coprolites leads us to think that these herbivores might not have been the main vectors for the spread and germination of algarrobos. More samples and interdisciplinary studies are needed to comprehend the complex socioecological web in the shaping of these forests and the management of the Atacama Desert landscapes.
Agricultural expansion into tropical and subtropical forests often leads to major social-ecological trade-offs. Yet, despite ever-more detailed information on where deforestation occurs, how agriculture expands into forests remains unclear, which is hampered by a lackof spatially and temporally detailed reconstruction of agricultural expansion. Here, we developed and mapped a novel set of metrics that quantify agricultural frontier processes at unprecedented spatial and temporal detail. Specifically, we first derived consistent annual time series of land-use/cover to, second, describe archetypical patterns of frontier expansion, pertaining to speed, diffusion and activity of deforestation, as well as post-deforestation land use. We exemplify this approach for understanding agricultural frontier expansion across the entire South American Chaco, a global deforestation hotspot. Our study provides three major insights. First, agricultural expansion has been rampant in the Chaco, with more than 19.3 million ha of woodlands converted between 1985 and 2020, including a surge in deforestation after 2019. Second, land-use trajectories connected to frontier processes have changed in major ways over the 35-year study period we studied, including substantial regional variations. For instance, while ranching expansion drove most of the deforestation in the 1980s and 1990s, cropland expansion dominated during the mid-2000s in Argentina, but not in Paraguay. Similarly, 40% of all areas deforested were initially used for ranching, but later on converted to cropping. Accounting for post-deforestation land-use change is thus needed to properly attribute deforestation and associated environmental impacts, such as carbon emissions or biodiversity loss, to commodities. Finally, we identified major, recurrent frontier types that may be a useful spatial template for land governance to match policies to specific frontier situations. Collectively, our study reveals the diversity of frontier processes and how frontier metrics can capture and structure this diversity to uncover major patterns of human-nature interactions, which can be used to guide spatially-targeted policies.
Most of the studies into the beneficial effects of chia were conducted with seeds. However, less evidence about the effects of cold pressed chia seeds oil on hypercholesterolemia-induced alterations has been found. Thus, this study investigated the effects of cold pressed chia seed oil supplementation on some clinical, hematological and biochemical biomarkers in both normal and hypercholesterolemic rabbits. All experimental protocols were approved by the Institutional Animal Ethics Committee (Approval number: 021/2019; Date: March 23th, 2021). 32 male rabbits were assigned to four different groups fed on: regular diet (CD), CD supplemented with 10% chia oil, CD supplemented with 1% cholesterol, CD supplemented with 1% cholesterol and 10% chia oil. After 6 weeks of dietary interventions, mean arterial blood pressure and visceral fat were measured and blood samples were analyzed for lipid profiles and hematological parameters while erythrocyte membranes and retroperitoneal fat were analyzed for fatty acids composition and biochemical biomarkers. Dietary intervention with chia oil reached to control hypercholesterolemia-induced increase of mean arterial blood pressure, neutrophil to lymphocytes ratio, erythrocyte membrane fluidity, and improved erythrocyte morphological alterations. With regard to inflammatory biomarkers, chia oil supplementation reduced omega-6/omega 3 polyunsaturated fatty acids ratio and arachidonic/linolenic fatty acids ratio both in erythrocytes and fat from normal and hypercholesterolemic rabbits. The increase of linolenic fatty acid into the retroperitoneal fat was about 9 times higher than its respective controls. These results provide support for the potential health benefits of the chia oil intake against hypercholesterolemia-associated clinical, hematological and biochemical alterations.
1. Studying species interactions in nature often requires elaborated logistics and intense fieldwork. The difficulties in such task might hinder our ability to answer questions on how biotic interactions change with the environment. Fortunately, a workaround to this problem lies within scientific collections. 2. For some animals, the inspection of preserved specimens can reveal the scars of past antagonistic encounters, such as predation attempts. A common defensive behaviour that leaves scars on animals is autotomy, the loss of a body appendage to escape predation. By knowing the collection site of preserved specimens,
Three coordination complexes {[Cu(pydco)(pz)0.5(H2O)]·H2O}n (1), [Cu(pydco)(phen)(H2O)]·2H2O (2), and [Zn2(pydco)(phen)2Cl2]·2H2O (3) have been synthesized at room temperature using a mixed-ligand system including pyridine-2,6-dicarboxylic acid N-oxide (H 2 pydco) as O-donor as well as pyrazine (pz) and 1,10-phenanthroline (phen) as N,N'-bidentate donors. Single-crystal X-ray diffraction (XRD) revealed that 1 forms a 1D-coordination polymer through bridging pz units while 2 and 3 form discrete complexes in which endo-bidentate phen can only connect with one metal centre via a five-membered chelate ring. Also, pydco 2-can form a six-membered chelate ring around the metal ion via the N-oxide oxygen and one carboxylate oxygen. However, another carboxylate group of this ligand can also participate in the coordination and create unique structures in 1 and 3. Subsequently, 1-3 can expand their structures into 2D-supramolecular networks through π⋯π stacking or H-bonding interactions. Recurrent π⋯π stacking motifs in all compounds have been further analyzed energetically using DFT calculations and characterized using the quantum theory of "atoms-in-molecules" (QTAIM) and noncovalent interaction plot (NCIPlot) index computational tools. In compound 3, cooperativity effects in π···π/π···π/π···π assemblies have been also analyzed.
In this research, the optimised structural and vibrational properties of cis–trans isomers of powerful insecticide allethrin were theoretically studied in gas phase and in aqueous and ethanol solutions by using hybrid B3LYP/6–311 + + g(d,p) level of theory. The results revealed that the permittivity of solvent has influence on the properties of both isomers, thus, higher dipole moments and solvation energies are observed in water, a solvent of higher permittivity (78.355) than ethanol. Complete vibrational assignments of both isomers were done by combining the experimental IR spectrum of allethrin with the scaled quantum mechanical force field (SQMFF) methodology and the determination of corresponding scaled force constants in gas phase and aqueous solution are reported. Different signs of dihedral O2C10C6C4 angles of both isomers (negative in cis and positive in trans) support the differences in the vibrational assignments. Natural bond orbital (NBO) calculations suggest that both isomers are highly stable in gas phase and aqueous solution and that the side chains and five member’s rings are involved in the n → σ* interactions. However, atoms in molecules (AIM) studies reveal a higher stability of form cis in both media than the trans one. Merz-Kollman (MK), Mulliken and natural population atomic (NPA) charges for both isomers support the higher hydration of trans isomer in aqueous media and, hence, the higher solvation energy in water (ΔGC/ZPVE = − 80.29 kJ/mol). Changes in the bond orders of O and C atoms of side chain are observed in water as a consequence of hydration. The higher stability of the cis form in the above solutions could be explained by the lower solvation energy in water, as supported by AIM calculations. The studies of frontier orbital reveal that the cis form in both media is sligthly more reactive than the trans form.Graphical abstract
High-fructose diet is associated with an increased risk of dyslipidemia, metabolic syndrome, and the development of non-alcoholic fatty liver disease (NAFLD) through chronic inflammation. The present study aimed to elucidate the potential benefit of daily consumption of Smallanthus sonchifolius (yacon) roots, rich in fructooligosaccharides (FOS), on the progression to liver fibrosis, in a rat model of NAFLD induced by a high-fructose diet. Male Wistar rats were fed a standard diet (CD, n = 6) or a standard diet plus 10% fructose solution (FD; n = 18). After 20 weeks, FD rats were randomly separated into the following groups (n = 6, each): FD; FD treated with yacon flour (340 mg FOS/body weight; FD + Y) and FD treated with fenofibrate (30 mg/kg body weight; FD + F), for 16 weeks. Daily intake of yacon flour significantly reduced body weight gain, plasma lipid levels, transaminase activities, and improved systemic insulin response in FD rats. In the liver, yacon treatment decreased fructose-induced steatosis and inflammation, and reduced total collagen deposition (64%). Also, yacon decreased TGF-β1 mRNA expression (78%), followed by decreased nuclear localization of p-Smad2/3 in liver tissue. Yacon significantly reduced the expression of α-smooth muscle actin (α-SMA), Col1α1, and Col3α1 mRNAs (85, 44, and 47%, respectively), inhibiting the activation of resident hepatic stellate cells (HSCs). These results suggested that yacon roots have the potential to ameliorate liver damage caused by long-term consumption of a high-fructose diet, being a promising nutritional strategy in NAFLD management.
In some tephritid fruit flies, exposure to volatile compounds from host plants increases male sexual success. This phenomenon has been used to boost sterile males’ sexual competitiveness in the framework of the sterile insect technique (SIT). Previous studies revealed that males of Anastrepha fraterculus (Diptera: Tephritidae) exposed to volatiles from guava (Psidium guajava) fruit (GF) and guava essential oil (GEO) exhibit intensified courtship behavior and have greater copulatory success relative to unexposed males. Similar results were achieved in these flies through exposure to moradillo (Schinus polygama) essential oil or lemon (Citrus limon) essential oil. To identify the responsible compounds involved in these effects, we compared the volatile chemical profiles of GF, GEO, moradillo essential oil, and lemon essential oil. We selected five candidate compounds: (E)-β-ocimene, (Z)-β-ocimene, limonene, β-caryophyllene, and α-humulene. Using the electroantennographic detection (EAD) technique, we verified that males are able to detect all the candidate compounds and built dose-response curves between 0.01 and 100 μg/μl for each compound. We confirmed a stimulating effect on the courtship behavior of males for (E/Z)-β-ocimene and (R)-limonene, whereas β-caryophyllene and α-Humulene did not affect male courtship behavior. For those compounds that sexually stimulated males, we found a dose-dependent effect. Males’ behavioral response to the semiochemicals was maximum when (R)-limonene was combined with (E/Z)-β-ocimene, but the response was reduced when β-caryophyllene and α-humulene were included, which suggests some sort of negative interaction between them. Our results may contribute to the ongoing development of the SIT in this species.
The study aimed to evaluate the ability of dominant lactic acid bacteria (LAB) in orange juice to growth on N-depleted MRS medium supplemented or not with cysteine (mMRS), then to select the most nutritionally promising strains for growth assays in the food matrix and evaluation of beneficial attributes for fruit juice fermentation. Levilactobacillus brevis and Lactiplantibacillus plantarum were dominant species among the total of 103 LAB isolates as confirmed by multiplex PCR and/or 16 s rDNA sequence analysis. Based on growing lower than 20% and higher than 70% in mMRS (1.0 g/l meat extract, without peptone and yeast extract) with and without cysteine requirement, one L. brevis (JNB23) and two L. plantarum (JNB21 and JNB25) were selected. These bacteria and the L. plantarum strains N4 and N8 (previously isolated from oranges peel) when inoculated in orange juice grew up to 1.0 log cfu/ml for 24 h incubation at 30 °C and mainly produced lactic acid, with strains JNB25 and JNB23 reaching the highest and lowest cell densities in agreement with their nutritional exigency. In addition, all L. plantarum strains exhibited antagonistic activity against the majority of tested bacterial pathogens (in opposition to L. brevis), ability to grow or survive to pH 3.0 for 3 h, to grow with 0.5% sodium taurocholate, and a decrease after simulated gastrointestinal digestion assay which did not exceed 1.0 or 2.0 log units, depending on the strain. Thus, autochthonous L. plantarum strains with ability for overcoming nutritional limitations and beneficial attributes are promising candidates for further investigations as novel probiotic and/or preservative starters to ferment citric fruit juices.
Undernutrition remains a major issue in global health. Low protein-energy consumption, results in stunting, wasting and/or underweight, three deleterious forms of malnutrition that affect roughly 200 million children under the age of five years. Undernutrition compromises the immune system with the generation of various degrees of immunodeficiency, which in turn, renders undernourished individuals more sensitive to acute infections. The severity of various infectious diseases including visceral leishmaniasis (VL), influenza, and tuberculosis is associated with undernutrition. Immunosuppression resulting from protein-energy undernutrition severely impacts primary and secondary lymphoid organs involved in the response to related pathogens. The thymus—a primary lymphoid organ responsible for the generation of T lymphocytes—is particularly compromised by both undernutrition and infectious diseases. In this respect, we will discuss herein various intrathymic cellular and molecular interactions seen in undernutrition alone or in combination with acute infections. Many examples illustrated in studies on humans and experimental animals clearly revealed that protein-related undernutrition causes thymic atrophy, with cortical thymocyte depletion. Moreover, the non-lymphoid microenvironmental compartment of the organ undergoes important changes in thymic epithelial cells, including their secretory products such as hormones and extracellular matrix proteins. Of note, deficiencies in vitamins and trace elements also induce thymic atrophy. Interestingly, among the molecular interactions involved in the control of undernutrition-induced thymic atrophy is a hormonal imbalance with a rise in glucocorticoids and a decrease in leptin serum levels. Undernutrition also yields a negative impact of acute infections upon the thymus, frequently with the intrathymic detection of pathogens or their antigens. For instance, undernourished mice infected with Leishmania infantum (that causes VL) undergo drastic thymic atrophy, with significant reduction in thymocyte numbers, and decreased levels of intrathymic chemokines and cytokines, indicating that both lymphoid and microenvironmental compartments of the organ are affected. Lastly, recent data revealed that some probiotic bacteria or probiotic fermented milks improve the thymus status in a model of malnutrition, thus raising a new field for investigation, namely the thymus-gut connection, indicating that probiotics can be envisioned as a further adjuvant therapy in the control of thymic changes in undernutrition accompanied or not by infection.
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1,076 members
Maria Guadalupe Vizoso Pinto
  • Instituto Superior de Investigaciones Biológicas
Natacha P. Chacoff
  • Instituto de Ecología Regional (IER)
Max Valentinuzzi
  • Departamento de Bioingeniería (INSIBIO)
Martin Gonzalo Sirombra
  • Departamento de Ecología
Fabiana Cuezzo
  • Instituto Superior de Entomología (INSUE)
Ayacucho 491, 4000, San Miguel de Tucumán, Tucumán, Argentina
Head of institution
Ing. José García