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Thermophilic microorganisms possess several adaptations to thrive in high temperature, which is reflected as biosynthesis of proteins and thermostable molecules, isolation and culture represent a great methodological challenge, therefore High throughput sequencing enables screening of the whole bacterial genome for functional potential, providing rapid and cost-effective information to guide targeted cultures for the identification and characterization of novel natural products. In this study, we isolated two thermophilic bacterial strains corresponding to Bacillus LB7 and Streptomyces LB8, from the microbial mats in the Atacama Desert. By combining genome mining, targeted cultures and biochemical characterization, we aimed to identify their capacity to synthesize bioactive compounds with antimicrobial properties. Additionally, we determined the capability to produce bioactive compounds under controlled in vitro assays and detected by determining their masses by Thin-Layer Chromatography/Mass Spectrometry (TLC/MS). Overall, both isolates can produce antimicrobial (e.g., Myxalamide C by-product) and antioxidants (e.g. Dihydroxymandelic Acid, Amide biotine and Flavone by-products) compounds. Bacillus LB7 strain possesses a more diverse repertoire with 51.95% of total metabolites unmatched, while Streptomyces LB8 favors mainly antioxidants, but has over 70% of unclassified compounds, highlighting the necessity to study and elucidate the structure of novel compounds. Based on these results, we postulate that the uncultured or rare cultured thermophiles inhabiting high-altitude hydrothermal ecosystems in the Atacama Desert offer a promising opportunity to the study of novel microbial bioactive compounds.

ABSTRACT The Atacama Desert is the oldest and driest desert on Earth, encompassing great temperature variations, high ultraviolet radiation, drought, and high salinity, making it ideal for studying the limits of life and resistance strategies. It is also known for harboring a great biodiversity of adapted life forms. While desertification is increasing as a result of climate change and human activities, it is necessary to optimize soil and water usage, where stress-resistant crops are possible solutions. As many studies have revealed the great impact of the rhizobiome on plant growth efficiency and resistance to abiotic stress, we set up to explore the rhizospheric soils of Suaeda foliosa and Distichlis spicata desert plants. By culturing these soils and using 16S rRNA amplicon sequencing, we address community taxonomy composition dynamics, stability through time, and the ability to promote lettuce plant growth. The rhizospheric soil communities were dominated by the families Pseudomonadaceae, Bacillaceae, and Planococcaceae for S. foliosa and Porphyromonadaceae and Haloferacaceae for D. spicata. Nonetheless, the cultures were completely dominated by the Enterobacteriaceae family (up to 98%). Effectively, lettuce plants supplemented with the cultures showed greater size and biomass accumulation. We identified 12 candidates that could be responsible for these outcomes, of which 5 (Enterococcus, Pseudomonas, Klebsiella, Paenisporosarcina, and Ammoniphilus) were part of the built co-occurrence network. We aim to contribute to the efforts to characterize the microbial communities as key for the plant’s survival in extreme environments and as a possible source of consortia with plant growth promotion traits aimed at agricultural applications.IMPORTANCEThe current scenario of climate change and desertification represents a series of incoming challenges for all living organisms. As the human population grows rapidly, so does the rising demand for food and natural resources; thus, it is necessary to make agriculture more efficient by optimizing soil and water usage, thus ensuring future food supplies. Particularly, the Atacama Desert (northern Chile) is considered the most arid place on Earth as a consequence of geological and climatic characteristics, such as the naturally low precipitation patterns and high temperatures, which makes it an ideal place to carry out research that seeks to aid agriculture in future conditions that are predicted to resemble these scenarios. Our main interest lies in utilizing microorganism consortia from plants thriving under extreme conditions, aiming to promote plant growth, improve crops, and render “unsuitable” soils farmable.

PURPOSEBreast cancer mortality rates in Latin America (LA) are higher than those in the United States, possibly because of advanced disease presentation, health care disparities, or unfavorable molecular subtypes. The Latin American Cancer Research Network was established to address these challenges and to promote collaborative clinical research. The Molecular Profiling of Breast Cancer Study (MPBCS) aimed to evaluate the clinical characteristics and treatment outcomes of LA participants with locally advanced breast cancer (LABC).PATIENTS AND METHODSThe MPBCS enrolled 1,449 participants from Argentina, Brazil, Chile, Mexico, and Uruguay. Through harmonized procedures and quality assurance measures, this study evaluated clinicopathologic characteristics, neoadjuvant chemotherapy response, and survival outcomes according to residual cancer burden (RCB) and the type of surgery.RESULTSOverall, 711 and 480 participants in the primary surgery and neoadjuvant arms, respectively, completed the 5-year follow-up period. Overall survival was independently associated with RCB (worse survival for RCBIII-adjusted hazard ratio, 8.19, P < .001, and RCBII [adjusted hazard ratio, 3.69, P < .008] compared with RCB0 [pathologic complete response or pCR]) and type of surgery (worse survival in mastectomy than in breast-conserving surgery [BCS], adjusted hazard ratio, 2.97, P = .001). The hormone receptor–negative-human epidermal growth factor receptor 2–positive group had the highest proportion of pCR (48.9%). The analysis of the ASCO Quality Oncology Practice Initiative breast module revealed high compliance with pathologic standards but lower adherence to treatment administration standards. Notably, compliance with trastuzumab administration varied widely among countries (33.3%-88.7%).CONCLUSIONIn LABC, we demonstrated the survival benefit of BCS and the prognostic effect of the response to available neoadjuvant treatments despite an important variability in access to key treatments. The MPBCS represents a significant step forward in understanding the real-world implementation of oncologic procedures in LA.

ABSTRACT The Salar de Huasco (SH) salt lake in northern Chile is an extreme environment characterized by high atmospheric pressure, UV radiation, salinity, variable temperatures, and the presence of heavy metals, including arsenic. Exiguobacterium bacteria have adapted to thrive in these challenging conditions and possess various resistance mechanisms, including biofilm formation, redox reactions, methylation, and altered respiration. In this study, Exiguobacterium strains isolated from the SH were assessed for their capacity to form biofilms in the presence of arsenic, a metalloid that exists in different oxidation states, in order to understand their resistance mechanisms to this heavy metal. The minimum inhibitory concentration (MIC) of each strain against different concentrations of arsenic [III] and [V], biofilm formation using crystal violet staining, and the expression of genes related to biofilm formation were evaluated. The structure of the biofilms was characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Furthermore, the extracellular polymeric substances (EPS) produced during biofilm formation were purified, quantified, and their composition determined. The results showed that the tested Exiguobacterium strains exhibit a significant ability to form biofilms when exposed to arsenic. This biofilm contributes to their arsenic resistance, shedding light on the underlying mechanisms. These findings enhanced our understanding of the biofilm formation process, its role in arsenic resistance, and the adaptive strategies employed by bacteria in extreme environments. This study also contributes to the field of microbial resistance mechanisms that have implications for environmental and biotechnological applications. IMPORTANCE In this work, we characterized the composition, structure, and functional potential for biofilm formation of Exiguobacterium strains isolated from the Salar de Huasco in Chile in the presence of arsenic, an abundant metalloid in the Salar that exists in different oxidation states. Our results showed that the Exiguobacterium strains tested exhibit a significant capacity to form biofilms when exposed to arsenic, which would contribute to their resistance to the metalloid. The results highlight the importance of biofilm formation and the presence of specific resistance mechanisms in the ability of microorganisms to survive and thrive under adverse conditions.

Introduction: Despite a government-subsidized vaccination program, healthcare personnel (HCP) influenza vaccination uptake remains low in Peru. Using three years of cross-sectional surveys and an additional five years of prior vaccination history of HCP in Peru, we explored HCP knowledge, attitudes, and practices (KAP) of influenza illness and its impact on vaccination frequency. Methods: In 2016, the Estudio Vacuna de Influenza Peru (VIP) cohort was initiated in Lima, Peru, which collected information about HCP KAP and influenza vaccination history from 2011─2018. HCP were classified by their 8-year influenza vaccination history as never (0 years), infrequently (1─4 years), or frequently (5─8 years) vaccinated. Logistic regression models were used to describe KAP associated with frequent compared to infrequent influenza vaccination, adjusted for each HCP’s healthcare workplace, age, sex, preexisting medical conditions, occupation, and length of time providing direct patient care. Results: From 2016─2018, 5131 HCP were recruited and 3120 fully enrolled in VIP; 2782 consistently reported influenza vaccination status and became our analytic sample. From 2011─2018, 14.3% of HCP never, 61.4% infrequently, and 24.4% frequently received influenza vaccines. Compared to HCP who were infrequently vaccinated, frequently vaccinated HCP were more likely to believe they were susceptible to influenza (adjusted odds ratio [aOR]:1.49, 95% confidence interval [CI]:1.22─1.82), perceived vaccination to be effective (aOR:1.92, 95%CI:1.59─2.32), were knowledgeable about influenza and vaccination (aOR:1.37, 95%CI:1.06─1.77), and believed vaccination had emotional benefits like reduced regret or anger if they became ill with influenza (aOR:1.96, 95%CI:1.60─2.42). HCP who reported vaccination barriers like not having time or a convenient place to receive vaccines had reduced odds of frequent vaccination (aOR:0.74, 95%CI:0.61─0.89) compared to those without reported barriers. Conclusion: Few HCP frequently received influenza vaccines during an eight-year period. To increase HCP influenza vaccination in middle-income settings like Peru, campaigns could strengthen influenza risk perception, vaccine knowledge, and accessibility.

The presence of mobile genetic elements in Salmonella isolated from a chicken farm constitutes a potential risk for the appearance of emerging bacteria present in the food industry. These elements contribute to increased pathogenicity and antimicrobial resistance through genes that are related to the formation of biofilms and resistance genes contained in plasmids, integrons, and transposons. One hundred and thirty-three Salmonella isolates from different stages of the production line, such as feed manufacturing, hatchery, broiler farm, poultry farm, and slaughterhouse, were identified, serotyped and sequenced. The most predominant serotype was Salmonella Infantis. Phylogenetic analyses demonstrated that the diversity and spread of strains in the pipeline are serotype-independent, and that isolates belonging to the same serotype are very closely related genetically. On the other hand, Salmonella Infantis isolates carried the pESI IncFIB plasmid harboring a wide variety of resistance genes, all linked to mobile genetic elements, and among carriers of these plasmids, the antibiograms showed differences in resistance profiles and this linked to a variety in plasmid structure, similarly observed in the diversity of Salmonella Heidelberg isolates carrying the IncI1-Iα plasmid. Mobile genetic elements encoding resistance and virulence genes also contributed to the differences in gene content. Antibiotic resistance genotypes were matched closely by the resistance phenotypes, with high frequency of tetracycline, aminoglycosides, and cephalosporins resistance. In conclusion, the contamination in the poultry industry is described throughout the entire production line, with mobile genetic elements leading to multi-drug resistant bacteria, thus promoting survival when challenged with various antimicrobial compounds.

Arsenic is a highly toxic metalloid of major concern for public safety. However, microorganisms have several resistance mechanisms, particularly the expression of arsenic pumps is a critical component for bacterial ability to expel it and decrease intracellular toxicity. In this study, we aimed to characterize the biochemical, structural, and genomic characteristics of the Acr3 pump among a group of Exiguobacterium strains isolated from different sites of the arsenic-rich Salar de Huasco (SH) ecosystem. We also determined whether the differences in As(III) resistance levels presented by the strains could be attributed to changes in the sequence or structure of this protein. In this context, we found that based on acr3 sequences the strains isolated from the SH grouped together phylogenetically, even though clustering based on gene sequence identity did not reflect the strain’s geographical origin. Furthermore, we determined the genetic context of the acr3 sequences and found that there are two versions of the organization of acr3 gene clusters, that do not reflect the strain’s origin nor arsenic resistance level. We also contribute to the knowledge regarding structure of the Acr3 protein and its possible implications on the functionality of the pump, finding that although important and conserved components of this family of proteins are present, there are several changes in the amino acidic sequences that may affect the interactions among amino acids in the 3D model, which in fact are evidenced as changes in the structure and residues contacts. Finally, we demonstrated through heterologous expression that the Exiguobacterium Acr3 pump does indeed improve the organisms As resistance level, as evidenced in the complemented E. coli strains. The understanding of arsenic detoxification processes in prokaryotes has vast biotechnological potential and it can also provide a lot of information to understand the processes of evolutionary adaptation.

Introduction: Among the various widely recognized basal cell carcinoma (BCC) clinical patterns, linear basal cell carcinoma (LBCC) is an uncommon morphologic variant of BCC. Objective: Describe the clinical and dermoscopic characteristics of LBCC. Methods: Retrospective study including LBCC cases from 5 dermatology centers in North and South America. Biopsy-proven primary BCCs, that presented with at least 3:1 length:width ratio on physical examination, irrespective of tumor subtype or location, were included. Clinical and dermoscopic analysis were performed by 2 experts in dermoscopy. Results: Eighteen cases of LBCC met our inclusion criteria and were included in the study. Median age at diagnosis was 86.0 years, 10 patients (58.8%) were males. Regarding anatomic location, 11/18 (61.1%) were located on the head and neck, 5/18 (27.7%) cases were found on the trunk, and 2 on lower extremities (11.1%). Under dermoscopy, 15/18 (83.3%) of LBCC were pigmented. All tumors displayed at least one of the BCC-specific dermoscopic criteria the most common being blue-grey globules (72.2%). Conclusions: Dermoscopy might be useful in the differentiation of LBCC from other diagnoses presenting as linear lesions such as scars, scratches/erosions, and tattoos, among others. Some of these lesions might be confused by naked eye examination alone.

Niemann-Pick type A (NPA) disease is a fatal lysosomal neurodegenerative disorder caused by the deficiency in acid sphingomyelinase (ASM) activity. NPA patients present severe and progressive neurodegeneration starting at an early age. Currently, there is no effective treatment for this disease and NPA patients die between 2 and 3 years of age. NPA is characterized by an accumulation of sphingomyelin in lysosomes and dysfunction in the autophagy-lysosomal pathway. Recent studies show that c-Abl tyrosine kinase activity downregulates autophagy and the lysosomal pathway. Interestingly, this kinase is also activated in other lysosomal neurodegenerative disorders. Here, we describe that c-Abl activation contributes to the mechanisms of neuronal damage and death in NPA disease. Our data demonstrate that: 1) c-Abl is activated in-vitro as well as in-vivo NPA models; 2) imatinib, a clinical c-Abl inhibitor, reduces autophagy-lysosomal pathway alterations, restores autophagy flux, and lowers sphingomyelin accumulation in NPA patient fibroblasts and NPA neuronal models and 3) chronic treatment with nilotinib and neurotinib, two c-Abl inhibitors with differences in blood-brain barrier penetrance and target binding mode, show further benefits. While nilotinib treatment reduces neuronal death in the cerebellum and improves locomotor functions, neurotinib decreases glial activation, neuronal disorganization, and loss in hippocampus and cortex, as well as the cognitive decline of NPA mice. Our results support the participation of c-Abl signaling in NPA neurodegeneration and autophagy-lysosomal alterations, supporting the potential use of c-Abl inhibitors for the clinical treatment of NPA patients.

ABSTRACT Microbial communities inhabiting extreme environments such as Salar de Huasco (SH) in northern Chile are adapted to thrive while exposed to several abiotic pressures and the presence of toxic elements such as arsenic (As). Hence, we aimed to uncover the role of As in shaping bacterial composition, structure, and functional potential in five different sites in this altiplanic wetland using a shotgun metagenomic approach. The sites exhibit wide gradients of As (9 to 321 mg/kg), and our results showed highly diverse communities and a clear dominance exerted by the Proteobacteria and Bacteroidetes phyla. Functional potential analyses show broadly convergent patterns, contrasting with their great taxonomic variability. As-related metabolism, as well as other functional categories such as those related to the CH4 and S cycles, differs among the five communities. Particularly, we found that the distribution and abundance of As-related genes increase as the As concentration rises. Approximately 75% of the detected genes for As metabolism belong to expulsion mechanisms; arsJ and arsP pumps are related to sites with higher As concentrations and are present almost exclusively in Proteobacteria. Furthermore, taxonomic diversity and functional potential are reflected in the 12 reconstructed high-quality metagenome assembled genomes (MAGs) belonging to the Bacteroidetes (5), Proteobacteria (5), Cyanobacteria (1), and Gemmatimonadetes (1) phyla. We conclude that SH microbial communities are diverse and possess a broad genetic repertoire to thrive under extreme conditions, including increasing concentrations of highly toxic As. Finally, this environment represents a reservoir of unknown and undescribed microorganisms, with great metabolic versatility, which needs further study. IMPORTANCE As microbial communities inhabiting extreme environments are fundamental for maintaining ecosystems, many studies concerning composition, functionality, and interactions have been carried out. However, much is still unknown. Here, we sampled microbial communities in the Salar de Huasco, an extreme environment subjected to several abiotic stresses (high UV radiation, salinity and arsenic; low pressure and temperatures). We found that although microbes are taxonomically diverse, functional potential seems to have an important degree of convergence, suggesting high levels of adaptation. Particularly, arsenic metabolism showed differences associated with increasing concentrations of the metalloid throughout the area, and it effectively exerts a significant pressure over these organisms. Thus, the significance of this research is that we describe highly specialized communities thriving in little-explored environments subjected to several pressures, considered analogous of early Earth and other planets, that have the potential for unraveling technologies to face the repercussions of climate change in many areas of interest.

Proton therapy has advantages and pitfalls comparing with photon therapy in radiation therapy. Among the limitations of protons in clinical practice we can selectively mention: uncertainties in range, lateral penumbra, deposition of higher LET outside the target, entrance dose, dose in the beam path, dose constraints in critical organs close to the target volume, organ movements and cost. In this review, we combine proposals under study to mitigate those pitfalls by using individually or in combination: (a) biological approaches of beam management in time (very high dose rate “FLASH” irradiations in the order of 100 Gy/s) and (b) modulation in space (a combination of mini-beams of millimetric extent), together with mechanical approaches such as (c) rotational techniques (optimized in partial arcs) and, in an effort to reduce cost, (d) gantry-less delivery systems. In some cases, these proposals are synergic (e.g., FLASH and minibeams), in others they are hardly compatible (mini-beam and rotation). Fixed lines have been used in pioneer centers, or for specific indications (ophthalmic, radiosurgery,…), they logically evolved to isocentric gantries. The present proposals to produce fixed lines are somewhat controversial. Rotational techniques, minibeams and FLASH in proton therapy are making their way, with an increasing degree of complexity in these three approaches, but with a high interest in the basic science and clinical communities. All of them must be proven in clinical applications.

Summary: The transcription factor EB (TFEB) has emerged as a master regulator of lysosomal biogenesis, exocytosis, and autophagy, promoting the clearance of substrates stored in cells. c-Abl is a tyrosine kinase that participates in cellular signaling in physiological and pathophysiological conditions. In this study, we explored the connection between c-Abl and TFEB. Here, we show that under pharmacological and genetic c-Abl inhibition, TFEB translocates into the nucleus promoting the expression of its target genes independently of its well-known regulator, mammalian target of rapamycin complex 1. Active c-Abl induces TFEB phosphorylation on tyrosine and the inhibition of this kinase promotes lysosomal biogenesis, autophagy, and exocytosis. c-Abl inhibition in Niemann-Pick type C (NPC) models, a neurodegenerative disease characterized by cholesterol accumulation in lysosomes, promotes a cholesterol-lowering effect in a TFEB-dependent manner. Thus, c-Abl is a TFEB regulator that mediates its tyrosine phosphorylation, and the inhibition of c-Abl activates TFEB promoting cholesterol clearance in NPC models.

Arsenopyrite is the most abundant arsenic-bearing sulfide mineral in the lithosphere, usually associated with sulfide gold ores. The recovery of this highly valuable metal is associated with the release of large quantities of soluble arsenic. One way to mitigate the effects of high concentrations of arsenic in solution is to immobilize it as scorodite precipitate, a more stable form. Hence, we addressed the scorodite formation capacity (under mesophilic conditions) of psychrotolerant Acidithiobacillus ferrivorans ACH isolated from the Chilean Altiplano. Bio-oxidation assays were performed with 1% arsenopyrite concentrate as unique energy source and produced solids were evaluated by X-ray diffraction (XRD) and QEMSCAN analysis. Interestingly, the results evidenced scorodite generation as the main sub-product after incubation for 15 days, due to the presence of the microorganism. Moreover, the QEMSCAN analysis support the XRD, detecting a 3.5% increase in scorodite generation by ACH strain and a 18.7% decrease in arsenopyrite matrix, implying an active oxidation. Finally, we presented the first record of arsenopyrite oxidation capacity and the stable scorodite production ability by a member of A. ferrivorans species under mesophilic conditions.

Polyextremophilic bacteria can thrive in environments with multiple stressors such as the Salar de Huasco (SH). Microbial communities in SH are exposed to low atmospheric pressure, high UV radiation, wide temperature ranges, salinity gradient and the presence of toxic compounds such as arsenic (As). In this work we focus on arsenic stress as one of the main adverse factors in SH and bacteria that belong to the Exiguobacterium genus due to their plasticity and ubiquity. Therefore, our aim was to shed light on the effect of niche conditions pressure (particularly arsenic), on the adaptation and divergence (at genotypic and phenotypic levels) of Exiguobacterium strains from five different SH sites. Also, to capture greater diversity in this genus, we use as outgroup five As(III) sensitive strains isolated from Easter Island (Chile) and The Great Salt Lake (United States). For this, samples were obtained from five different SH sites under an arsenic gradient (9 to 321 mg/kg: sediment) and isolated and sequenced the genomes of 14 Exiguobacterium strains, which had different arsenic tolerance levels. Then, we used comparative genomic analysis to assess the genomic divergence of these strains and their association with phenotypic differences such as arsenic tolerance levels and the ability to resist poly-stress. Phylogenetic analysis showed that SH strains share a common ancestor. Consequently, populations were separated and structured in different SH microenvironments, giving rise to multiple coexisting lineages. Hence, this genotypic variability is also evidenced by the COG (Clusters of Orthologous Groups) composition and the size of their accessory genomes. Interestingly, these observations correlate with physiological traits such as growth patterns, gene expression, and enzyme activity related to arsenic response and/or tolerance. Therefore, Exiguobacterium strains from SH are adapted to physiologically overcome the contrasting environmental conditions, like the arsenic present in their habitat.

Abstract Background Transformation of follicular lymphoma most typically occurs as diffuse large B-cell lymphoma, however other forms of transformation such as classic Hodgkin lymphoma and lymphoblastic transformation can occur. Secondary malignant histiocytosis also represents a rare form of transformation, which is thought to occur due to a process of transdifferentiation whereby the lymphoma cells exhibit lineage plasticity and lose all evidence of B-cell phenotype and instead acquire the phenotype of a histiocytic neoplasm. Little is known about the underlying genetic alterations that occur during this unusual process. Comparative genetic analysis of pre- and post-transformation/transdifferentiation would be one tool by which we could better understand how this phenomenon occurs. Case presentation Here we report the clinical, immunophenotypic and genetic features of a rare case of secondary malignant histiocytosis, Langerhans cell-type (Langerhans cell sarcoma) arising from a previous low grade follicular lymphoma. FISH analysis confirmed the presence of IgH/BCL2 rearrangement in both the low grade follicular lymphoma (FL) and transformed Langerhans cells sarcoma (LCS) samples, demonstrating a clonal relationship. Comparative whole exome sequencing was then performed, which identified a KRAS p.G13D mutation in the LCS that was not present in the FL. Conclusions This report highlights genetic alterations, in particular an acquired somatic KRAS mutation, that may occur during transdifferentiation, with additional significance of KRAS mutation as a possible therapeutic target in cases which otherwise would have limited treatment options.

Salmonella Typhimurium, a bacterial pathogen with high metabolic plasticity, can adapt to different environmental conditions; these traits enhance its virulence by enabling bacterial survival. Neutrophils play important roles in the innate immune response, including the production of microbicidal reactive oxygen species (ROS). In addition, the myeloperoxidase in neutrophils catalyzes the formation of hypochlorous acid (HOCl), a highly toxic molecule that reacts with essential biomolecules, causing oxidative damage including lipid peroxidation and protein carbonylation. The bacterial response regulator ArcA regulates adaptive responses to oxygen levels and influences the survival of Salmonella inside phagocytic cells. Here, we demonstrate by whole transcriptomic analyses that ArcA regulates genes related to various metabolic pathways, enabling bacterial survival during HOCl-stress in vitro. Also, inside neutrophils, ArcA controls the transcription of several metabolic pathways by downregulating the expression of genes related to fatty acid degradation, lysine degradation, and arginine, proline, pyruvate, and propanoate metabolism. ArcA also upregulates genes encoding components of the oxidative pathway. These results underscore the importance of ArcA in ATP generation inside the neutrophil phagosome and its participation in bacterial metabolic adaptations during HOCl stress.

Salmonella comprises over 2500 serotypes and foodborne contamination associated with this pathogen remains an important health concern worldwide. During the last decade, a shift in serotype prevalence has occurred as traditionally less prevalent serotypes are increasing in frequency of infections, especially those related to poultry meat contamination. S. Infantis is one of the major emerging serotypes, and these strains commonly display antimicrobial resistance and can persist despite cleaning protocols. Thus, this work aimed to isolate S. Infantis strains from a poultry meat farm in Santiago, Chile and to characterize genetic variations present in them. We determined their genomic and phenotypic profiles at different points along the production line. The results indicate that the strains encompass 853 polymorphic sites (core-SNPs) with isolates differing from one another by 0–347 core SNPs, suggesting variation among them; however, we found discrete correlations with the source of the sample in the production line. Furthermore, the pan-genome was composed of 4854 total gene clusters of which 2618 (53.9%) corresponds to the core-genome and only 181 (3.7%) are unique genes (those present in one particular strain). This preliminary analysis will enrich the surveillance of Salmonella, yet further studies are required to assess their evolution and phylogeny.

The beef cattle production system in the east area of Caldenal tends to concentrate the parturition in a short period of time, adjusting the availability of forage production with the maximum nutrient herd demando Nevertheless the current system has the main disadvantage to offer weaning calf in a tiny period of time affecting negatively both the sale price and the provision of animal to feed lot that demand animal year round. The objective of the project was to develop a new methodology to distribute the calving around the year in arder 10 increase the economic and reproductive efficiencies . It was chosen six beef herd on native pasture in the Caldenal area with strategic energy supplementation. The breeding season was planned to be of 90 days of duration, where the last 30 days of breeding of the initial herd mach with the first 30 days of the fol1owing. The percentage of calving detected by the alternative method were the same or higher to those observed by the traditional system

MLN64 is a late endosomal cholesterol-binding membrane protein that has been implicated in cholesterol transport from endosomal membranes to the plasma membrane and/or mitochondria, in toxin-induced resistance, and in mitochondrial dysfunction. Down-regulation of MLN64 in Niemann-Pick C1 deficient cells decreased mitochondrial cholesterol content, suggesting that MLN64 functions independently of NPC1. However, the role of MLN64 in the maintenance of endosomal cholesterol flow and intracellular cholesterol homeostasis remains unclear. We have previously described that hepatic MLN64 overexpression increases liver cholesterol content and induces liver damage. Here, we studied the function of MLN64 in normal and NPC1-deficient cells and we evaluated whether MLN64 overexpressing cells exhibit alterations in mitochondrial function. We used recombinant-adenovirus-mediated MLN64 gene transfer to overexpress MLN64 in mouse liver and hepatic cells; and RNA interference to down-regulate MLN64 in NPC1-deficient cells. In MLN64-overexpressing cells, we found increased mitochondrial cholesterol content and decreased glutathione (GSH) levels and ATPase activity. Furthermore, we found decreased mitochondrial membrane potential and mitochondrial fragmentation and increased mitochondrial superoxide levels in MLN64-overexpressing cells and in NPC1-deficient cells. Consequently, MLN64 expression was increased in NPC1-deficient cells and reduction of its expression restore mitochondrial membrane potential and mitochondrial superoxide levels. Our findings suggest that MLN64 overexpression induces an increase in mitochondrial cholesterol content and consequently a decrease in mitochondrial GSH content leading to mitochondrial dysfunction. In addition, we demonstrate that MLN64 expression is increased in NPC cells and plays a key role in cholesterol transport into the mitochondria.

Non-crop cultivated plants can provide agriculture with ecosystem services, such as biological pest control and, a sound knowledge of the relationships between these plants and arthropod communities is important. Given its entomophilous characteristics, Dittrichia viscosa, a plant commonly found in the Mediterranean region, could potentially be used in integrated pest management systems. The aim of this study is to investigate arthropofauna associated with D. viscosa in olive groves during its pre-flowering, flowering and post-flowering stages and to determine the possible relationships between different groups of arthropods. Using vacuum-sampling, the study was carried out on D. viscosa plants bordering and inside olive groves. The plants produced new leaves in April and flowered between August and October. Miridae, Aphididae, Hymenoptera parasitoids, Formicidae, Araneae, and Aleyrodidae were the most abundant groups of arthropods collected during the pre-flowering and flowering stages. Plant phenology differentially influenced the arthropod populations of the different groups, with the Aleyrodidae family found to be more abundant during the pre-flowering stage, while Hymenoptera parasitoids were more numerous during the flowering stage. During the post-flowering stage, the number of arthropods captured was very low. Numerous correlations between and within the different functional groups were observed throughout the life cycle of D. viscosa. Our results clearly show that D. viscosa plants in olive groves have great potential as a reservoir of different predators and Hymenoptera parasitoids and that these olive groves were not attacked by any D. viscosa-related phytophages.

Exiguobacterium is a polyextremophile bacterial genus with a physiology that allows it to develop in different adverse environments. The Salar de Huasco is one of these environments due to its altitude, atmospheric pressure, solar radiation, temperature variations, pH, salinity, and the presence of toxic compounds such as arsenic. However, the physiological and/or molecular mechanisms that enable them to prosper in these environments have not yet been described. Our research group has isolated several strains of Exiguobacterium genus from different sites of Salar de Huasco, which show different resistance levels to As(III) and As(V). In this work, we compare the protein expression patterns of the three strains in response to arsenic by a proteomic approach; strains were grown in absence of the metalloid and in presence of As(III) and As(V) sublethal concentrations and the protein separation was carried out in 2D electrophoresis gels (2D-GE). In total, 999 spots were detected, between 77 and 173 of which showed significant changes for As(III) among the three strains, and between 90 and 143 for As(V), respectively, compared to the corresponding control condition. Twenty-seven of those were identified by mass spectrometry (MS). Among these identified proteins, the ArsA [ATPase from the As(III) efflux pump] was found to be up-regulated in response to both arsenic conditions in the three strains, as well as the Co-enzyme A disulfide reductase (Cdr) in the two more resistant strains. Interestingly, in this genus the gene that codifies for Cdr is found within the genic context of the ars operon. We suggest that this protein could be restoring antioxidants molecules, necessary for the As(V) reduction. Additionally, among the proteins that change their expression against As, we found several with functions relevant to stress response, e.g., Hpf, LuxS, GLpX, GlnE, and Fur. This study allowed us to shed light into the physiology necessary for these bacteria to be able to tolerate the toxicity and stress generated by the presence of arsenic in their niche.

[This corrects the article DOI: 10.1371/journal.pone.0203497.].

Esta pesquisa tenta estabelecer um diálogo entre a crítica literária do séc. XXI e o marxismo, por meio da obra crítica ensaística de Roberto Bolaño Entre paréntesis (2011). Nesta publicação, Bolaño discute algumas das vozes narrativas do séc. XX, no viés crítico geopolítico em que se movimentam, canonizadas ou não, definindo, inflexivamente, um passo ao estudo da narrativa não-cânone. Nesse sentido, acredita-se que Bolaño, ao fundamentar a obra contemporânea, na descontinuidade (GONZÁLEZ, 2010), cria uma inflexão crítica que se desprende do marxismo dialético, na aliança entre o real e a ficção, numa narração latino-americana de finais do século passado.

Niemann–Pick type C disease (NPCD) is a lysosomal storage disease (LSD) characterized by abnormal cholesterol accumulation in lysosomes, impaired autophagy flux, and lysosomal dysfunction. The activation of transcription factor EB (TFEB), a master lysosomal function regulator, reduces the accumulation of lysosomal substrates in LSDs where the degradative capacity of the cells is compromised. Genistein can pass the blood–brain barrier and activate TFEB. Hence, we investigated the effect of TFEB activation by genistein toward correcting the NPC phenotype. We show that genistein promotes TFEB translocation to the nucleus in HeLa TFEB-GFP, Huh7, and SHSY-5Y cells treated with U18666A and NPC1 patient fibroblasts. Genistein treatment improved lysosomal protein expression and autophagic flux, decreasing p62 levels and increasing those of the LC3-II in NPC1 patient fibroblasts. Genistein induced an increase in β-hexosaminidase activity in the culture media of NPC1 patient fibroblasts, suggesting an increase in lysosomal exocytosis, which correlated with a decrease in cholesterol accumulation after filipin staining, including cells treated with U18666A and NPC1 patient fibroblasts. These results support that genistein-mediated TFEB activation corrects pathological phenotypes in NPC models and substantiates the need for further studies on this isoflavonoid as a potential therapeutic agent to treat NPCD and other LSDs with neurological compromise.

SUMMARY The whole-body iodine-131 scintigraphy is an imaging technique in monitoring patients with a history of thyroid cancer. Although the rate of false positives is negligible, it is not nonexistent. We report the case of an intervened and treated patient for thyroid cancer with good clinical and biochemical response. Scintigraphic findings were consistent with unsuspected bone metastasis. Fused SPECT/CT data allowed accurate diagnosis of giant diaphragmatic hernia associated with intrathoracic stomach, a very rare pathology that can lead to false positive results.

Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant Exiguobacterium strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity. However, to date, there are no studies regarding the tolerance and resistance to salinity and osmotic pressure. We set out to characterize the Exiguobacterium sp. SH31 strain and describe its phenotypical and genotypical response to osmotic stress. In this context, as a first step to characterize the response to the SH31 strain to salinity and to establish the bases for a molecular study, we proposed to compare its response under three salt conditions (0, 25, and 50 g/l NaCl). Using different physiology, genomic, and transcriptomic approaches, we determined that the bacterium is able to grow properly in a NaCl concentration of up to 50 g/l; however, the best growth rate was observed at 25 g/l. Although the presence of flagella is not affected by salinity, motility was diminished at 25 g/l NaCl and abolished at 50 g/l. Biofilm formation was induced proportionally with increases in salinity, which was expected. These phenotypic results correlated with the expression of related genes: fliG and fliS Motility); opuBA and putP (transport); glnA, proC, gltA, and gbsA (compatible solutes); ywqC, bdlA, luxS y pgaC (biofilm and stress response); and therefore, we conclude that this strain effectively modifies gene expression and physiology in a differential manner when faced with different concentrations of NaCl and these modifications aid survival.

Salmonella enterica Serovar Typhimurium (S. Typhimurium) is an intracellular bacterium that overcomes host immune system barriers for successful infection. The bacterium colonizes the proximal small intestine, penetrates the epithelial layer, and is engulfed by macrophages and neutrophils. Intracellularly, S. Typhimurium encounters highly toxic reactive oxygen species including hydrogen peroxide and hypochlorous acid. The molecular mechanisms of Salmonella resistance to intracellular oxidative stress is not completely understood. The ArcAB two-component system is a global regulatory system that responds to oxygen. In this work, we show that the ArcA response regulator participates in Salmonella adaptation to changing oxygen levels and is also involved in promoting intracellular survival in macrophages and neutrophils, enabling S. Typhimurium to successfully establish a systemic infection.

This work presents a software application to identify, in real time, the respiratory movements -inspiration and expiration- through a microphone. The application, which has been developed in Matlab and named ASBSLAB for the GUI version and ASBSLABCONSOLE for the command-line version, is the result of a research and experimentation process. A total of 48 minutes of breathing movements from four subjects was recorded and 18 acoustic features were extracted to generate the data model. A first level of identification, based on the classification of tiny audio segments, was designed using kNN supervised method. The second level of identification implements a state machine that takes the results ordered in the time from kNN as input and identifies the whole respiratory movement, achieving a level of positive identifications above 95%. As computation time is a handicap, the application let the user choose easily the sample rate, the audio segment size and the set of acoustic features to use in the identification process. In addition, based on the number of features selected, this works suggests those that achieve best results.

En las plantas las antocianinas cumplen roles fundamentales en sus interacciones con el medio ambiente, son una de las líneas de defensa contra los radicales libres, la radiación ultravioleta y el ataque de patógenos. Observaciones realizadas muestran que los frutos de M. dubia acumulan antocianinas alrededor de lesiones mecánicas probablemente causadas por insectos. Por tanto, hemos probado la hipótesis que produciendo lesiones mecánicas en frutos verdes de M. dubia se induce la biosíntesis local de antocianinas. De tres plantas en fructificación de la colección de germoplasma del INIA se seleccionaron aleatoriamente 40 frutos verdes (25 ± 5 mm de Ø) y se causaron lesiones mecánicas con estilete o bisturí al 75% de ellos. Posteriormente, se registró el porcentaje de acumulación de antocianinas por área superficial del fruto a las 0, 24, 48 y 72 horas. Se observó acumulación de antocianinas en ~10% (24 horas), ~30% (48 horas) y ~70% (72 horas) del área superficial de los frutos. En conclusión, las lesiones mecánicas causadas en frutos de M. dubia inducen la biosíntesis local de antocianinas, probablemente como un mecanismo de defensa efectivo desarrollado por esta especie. La comprensión de los mecanismos moleculares implicados en esta respuesta fisiológica nos permitirá establecer las bases para la mejora genética de esta especie.

Las infecciones diarreicas agudas (IDAs) son problemas comunes en niños menores de 5 años en nuestro país y la Región Loreto. Sin embargo, se desconocen los agentes microbiológicos causales de estas infecciones. Para cubrir estos vacíos en el conocimiento, el objetivo de esta investigación fue realizar la identificación molecular de Escherichia coli enterotoxigénica (ECET) en niños con infecciones diarreicas agudas mediante la Reacción en Cadena de la Polimerasa (PCR). Se colectaron 188 muestras diarreicas de niños menores de cinco años de siete Centros de Salud de Iquitos. A partir de estas se aislaron cepas de E. coli, se extrajo el ADN y amplificó regiones de los genes que codifican las enterotoxinas lábil al calor (LT) y estable al calor (ST). De los 188 casos con IDAs se ha encontrado que ~83% son atribuibles a infecciones por cepas de E. coli y de estas ~18% fueron identificadas molecularmente como ECET por presentar el gen LT (19) o el gen ST (9). En conclusión, la mayoría de las IDAs en niños < 5 años de Iquitos están asociadas con cepas de E. coli. Una fracción importante de estas cepas han sido identificadas molecularmente (mediante PCR) y demostrado que pertenecen al patotipo ECET. Asimismo, se ha evidenciado que las cepas ECET portadoras del gen LT predominan con respecto a las que tienen el gen ST y no se ha encontrado cepas ECET que porten de forma simultánea ambos genes.

En las plantas las antocianinas cumplen roles fundamentales en sus interacciones con el medio ambiente, son una de las líneas de defensa contra los radicales libres, la radiación ultravioleta y el ataque de patógenos. Observaciones realizadas muestran que los frutos de M. dubia acumulan antocianinas alrededor de lesiones mecánicas probablemente causadas por insectos. Por tanto, hemos probado la hipótesis que produciendo lesiones mecánicas en frutos verdes de M. dubia se induce la biosíntesis local de antocianinas. De tres plantas en fructificación de la colección de germoplasma del INIA se seleccionaron aleatoriamente 40 frutos verdes (25 ± 5 mm de Ø) y se causaron lesiones mecánicas con estilete o bisturí al 75% de ellos. Posteriormente, se registró el porcentaje de acumulación de antocianinas por área superficial del fruto a las 0, 24, 48 y 72 horas. Se observó acumulación de antocianinas en ~10% (24 horas), ~30% (48 horas) y ~70% (72 horas) del área superficial de los frutos. En conclusión, las lesiones mecánicas causadas en frutos de M. dubia inducen la biosíntesis local de antocianinas, probablemente como un mecanismo de defensa efectivo desarrollado por esta especie. La comprensión de los mecanismos moleculares implicados en esta respuesta fisiológica nos permitirá establecer las bases para la mejora genética de esta especie.

En el presente trabajo se intentarán abordar las problemáticas que existen en las unidades penitenciarias con respecto al acceso a la educación, teniendo en cuenta la situación en la que se encuentran los sujetos privados de su libertad. Luego se verá el marco normativo que prevé la educación en las cárceles (artículos 2 y 140 de la ley 24.660, tratados internacionales); las modificaciones legislativas (Ley de Estímulo Educativo) y las dificultades que existen para llevarlas a cabo. Asimismo, será relevante determinar si el Estado cumple con las obligaciones que le son inherentes respecto al goce de los derechos de las personas que son privadas de su libertad, sobre todo en lo que respecta a la educación. Por último, se esgrimirá la importancia de la educación en las cárceles y su recepción en el marco normativo tanto internacional como nacional.

Mauritia flexuosa es una especie vegetal amazónica que forma extensas poblaciones denominadas “aguajales”. Como los pobladores amazónicos emplean varios órganos de M. flexuosa para suplir sus necesidades y con fines comerciales, se está ejerciendo un gran impacto negativo sobre esta especie. A pesar de ello, a la fecha no se conoce la diversidad genética de esta especie en la Amazonía peruana. Consecuentemente, los planes de manejo para la especie serían limitados sin este tipo de información. Por tanto, el objetivo de esta investigación fue determinar la diversidad genética y filogenia molecular de poblaciones de M. flexuosa aledañas a la carretera Iquitos-Nauta. Las hojas se colectaron en seis zonas contiguas a la carretera Iquitos–Nauta. El ADN purificado con protocolos estándares fue amplificado mediante la técnica de ADN Polimórfico Amplificado al Azar (RAPD) con dos cebadores aleatorios. En total se generaron 28 amplicones RAPD (26 polimórficos y 2 monomórficos). Dentro de los aguajales la diversidad genética fue tres veces mayor (75±19 %) que la diversidad genética entre las seis poblaciones de M. flexuosa (25±19 %). La diferenciación genética entre las poblaciones varió de 0,0 a 0,6. Los aguajales que se agruparon en clados en el dendrograma por su mayor similitud genética tuvieron proximidad geográfica. La similitud genética entre las poblaciones de M. flexuosa depende de la distancia geográfica, de tal manera que las poblaciones con más similitud genética están más próximas entre sí que las que tienen menos similitud genética.

Treatment of high grade gliomas (HGGs) has remained elusive due to their high heterogeneity and aggressiveness. Surgery followed by radiotherapy represents the mainstay of treatment for HGG. However, the unfavorable location of the tumor that usually limits total resection and the resistance to radiation therapy are the major therapeutic problems. Chemotherapy with DNA alkylating agent temozolomide is also used to treat HGG, despite modest effects on survival. Disregulation of several growth factor receptors (GFRs) were detected in HGG and receptor amplification in glioblastoma has been suggested to be responsible for heterogeneity propagation through clonal evolution. Molecularly targeted agents inhibiting these membrane proteins have demonstrated significant cytotoxicity in several types of cancer cells when tested in preclinical models. Platelet-derived growth factor receptors (PDGFRs) and associated signaling were found to be implicated in gliomagenesis, moreover, HGG commonly display a Platelet-derived growth factor (PDGF) autocrine pathway that is not present in normal brain tissues. We have previously shown that both the susceptibility towards PDGFR and the impact of the PDGFR inactivation on the radiation response were different in different HGG cell lines. Therefore, we decided to extend our investigation, using two other HGG cell lines that express PDGFR at the cell surface. Here, we investigated the effect of PDGFR inhibition alone or in combination with gamma radiation in 11 and 15 HGG cell lines. Our results showed that while targeting the PDGFR represents a good means of treatment in HGG, the combination of receptor inhibition with gamma radiation did not result in any discernable difference compared to the single treatment. The PI3K/PTEN/Akt/mTOR and Ras/Raf/MEK/ERK pathways are the major signaling pathways emerging from the GFRs, including PDGFR. Decreased sensitivity to radiation-induced cell death are often associated with redundancy in these pro-survival signaling pathways. Here we found that Phosphoinositide 3-kinases (PI3K), Extracellular-signal-regulated kinase 1/2 (ERK1/2), or c-Jun N-terminal kinase 1/2 (JNK1/2) inactivation induced radiosensitivity in HGG cells.

Myrciaria dubia muestra una amplia variación en la producción de vitamina C (vit.C). Para entender las bases moleculares de esta variación, se determinó la relación del nivel de expresión genética y actividad de GDP-Manosa pirofosforilasa (GMP) con la variación del contenido de vit.C en M. dubia. Las muestras fueron obtenidas de una colección de germoplasma. La vit.C se cuantificó por HPLC, la actividad de GMP se midió por espectrofotometría. El ARN se purificó, el ADNc se sintetizó, amplificó, clonó y secuenció con técnicas estándares. La expresión del gen se midió mediante PCR en tiempo real. Las diferencias en el contenido de vit.C de las hojas, pulpa y cáscara dependieron de la expresión y actividad de GMP. Esta relación también se observó entre plantas que producen frutos con bajo y alto contenido de vit.C. En conclusión, Las hojas, pulpa y cáscara de M. dubia muestran diferencias significativas en el contenido de vit.C, el cual se atribuye a la expresión y actividad catalítica diferencial de la GMP. Asimismo, las plantas que producen frutos con diferencias marcadas en el contenido de vit.C en sus pulpas, también dependen del nivel de expresión y actividad catalítica de esta enzima.

La amazonía peruana es megabiodiversa y posee millones de genes con potencial biotecnológico que debemos descubrir. Para identificarlos, aislarlos y poder aprovecharlos tenemos que secuenciar los genomas y transcriptomas de las especies más importantes. Sin embargo, hasta concretar este tipo de proyectos, combinando estrategias bioinformáticas y moleculares podemos aislar genes con potencial biotecnológico. El objetivo fue aislar genes involucrados en la biosíntesis de vitamina C en Myrciaria dubia. De acuerdo a las relaciones filogenéticas de M. dubia con otras especies, se buscaron secuencias homólogas en el banco de genes del gen que codifica L-galactono-1,4-lactona deshidrogenasa (L-GalLDH). En base al alineamiento múltiple obtenido, se construyó un filograma consenso y de los clados formados se diseñaron cebadores degenerados. Los frutos fueron obtenidos de una colección de germoplasma y el ARN total se purificó, el ADNc se sintetizó y amplificó con cebadores degenerados. El amplicón sintetizado se clonó y secuenció con técnicas estándares. Con las aproximaciones empleadas se logró aislar, clonar y secuenciar un segmento de 921 pb del gen L-GalLDH de M. dubia. En conclusión, con las estrategias bioinformáticas y moleculares descritas se aisló el segmento de un gen que codifica la enzima L-galactono-1,4-lactona deshidrogenasa de la vía biosintética de vitamina C en M. dubia, especie de la que no se disponía de secuencias génicas. Con estas mismas aproximaciones será posible aislar genes de interés biotecnológico de esta y otras especies amazónicas que aún no cuentan con bases de datos de secuencias nucleotídicas.

Dioscorea trifida “sachapapa” es una de las especies promisorias amazónicas que podemos considerarla huérfana de la ciencia, por las escasas investigaciones que hay sobre esta especie. El objetivo de esta investigación fue determinar la diversidad genética intra e interpoblacional de D. trifida de cinco cuencas hidrográficas de la amazonía peruana. Las hojas fueron colectadas de una colección de germoplasma y purificó el ADN con métodos estándares. El polimorfismo genético se evaluó con la técnica RAPD y los parámetros de genética poblacional fueron estimados con el programa POPGENE. Los análisis espectrofotométrico (A260/A280=1,7±0,1) y electroforético (bandas de ADN íntegras) mostraron que el ADN purificado fue de alta calidad. Asimismo, la cantidad obtenida fue apropiada para estudios de diversidad genética (rendimiento promedio = 582±248 mg ADN/mg hojas). La diversidad genética intrapoblacional más alta se encontró en la cuenca del Itaya (h = 0,24±0,11) y la más baja en la cuenca del Marañón (h = 0,10±0,04). Adicionalmente, la diversidad genética interpoblacional más alta se registró entre las poblaciones de Itaya vs Ucayali (GST = 1,00), mientras que la más baja entre las poblaciones de Nanay vs Tapiche (GST = 0,07). En conclusión, D. trifida muestra variación en su diversidad genética intra e interpoblacional en las cinco cuencas hidrográficas de la amazonía peruana, siendo la cuenca del Itaya la que presenta mayor diversidad genética intrapoblacional y las poblaciones de Itaya vs Ucayali las que presentan mayor diversidad genética interpoblacional, que en parte se atribuyen al flujo de genes diferencial entre las poblaciones analizadas.

Myrciaria dubia “camu camu” es un frutal del trópico amazónico caracterizado por sus frutos con gran contenido de vitamina C, siendo considerado un producto importante del país. Sin embargo, hay pocos reportes sobre el metabolismo y transporte de vitamina C en esta especie. El objetivo de la investigación fue determinar la fluctuación diurna del contenido de vitamina C en hojas de M. dubia “camu camu”. Las hojas se colectaron de la colección de germoplasma de “camu camu” del INIA a las 2, 6, 10, 14, 18 y 22 horas; de cuatro plantas y en tres fechas diferentes. La vitamina C fue extraída de las hojas con un método estandarizado en el laboratorio y se cuantificó mediante espectrofotometría a 530nm, previa reacción con 2,6-diclorofenolindofenol. Los resultados muestran que el contenido de vitamina C de las hojas de “camu camu” fue en promedio 231±35 mg vitamina C/100g de hoja. Además, el contenido de vitamina C en las hojas del “camu camu” mostró fluctuación diurna, siendo menor a las 6 horas y mayor a las 2 y 14 horas del día. También, se registraron concentraciones intermedias en horas de menor o ausencia de radiación solar (235±17 y 237±35 mg vitamina C/100g de hoja a las 18 y 22 horas respectivamente). Se concluye que existe alto contenido de vitamina C en las hojas del “camu camu” y que este contenido presenta fluctuación diurna.

Las microalgas oleaginosas constituyen una nueva alternativa para la producción de biodiesel, por su alta eficiencia fotobiosintética de triglicéridos y presentan productividades mayores de 10 a 100 veces que los cultivos convencionales. Además, que actúan como sumideros de CO2 y pueden usar aguas servidas para producir biodiesel. Sin embargo, los estudios sobre identificación de este tipo de microalgas en la amazonía son escasos. El objetivo del presente trabajo de investigación fue identificar especies de microalgas oleaginosas con potencial aplicación para la producción de biodiesel que se encuentran en ambientes acuáticos del Área de Concesión para Conservación de la Universidad Científica del Perú (UCP). La colecta de las muestras se realizó del 27/06/12 al 03/07/12 entre las 12 y 15 h utilizando red planctónica tipo cono y como preservante formol al 3%. La identificación microscópica se realizó en el Laboratorio de Ciencias Básicas de la UCP. La densidad de las microalgas fue realizada en base a su conteo en cámaras de Neubauer y Sedgwick-Rafter. Los resultados muestran la presencia de 20 especies de microalgas, de las cuales cinco son microalgas oleaginosas. Correspondiente a las del género Chlorella quienes presentaron la mayor densidad promedio (6x104 células/ml) en las tres cochas evaluadas.

Myrciaria dubia “camu-camu” es un frutal amazónico caracterizado por su amplia variación de vitamina C. Pero los estudios genético moleculares que puedan explicar esta variación son limitados. Por ello nuestro objetivo fue realizar la clonación y filogenia molecular de un segmento del gen codante de la actina de M. dubia. Las muestras fueron obtenidas de la colección de germoplasma del INIA. Luego, el ARN fue purificado y mediante RT-PCR con cebadores degenerados se amplificó un segmento del gen. En base a la secuencia obtenida se diseñaron cebadores específicos para PCR en tiempo real. Los resultados muestran que se ha aislado, clonado y secuenciado un segmento del gen codante de actina de M. dubia y detectado su expresión en hojas, pulpa y cáscara de M. dubia. Así, con el soporte de herramientas bioinformáticas y uso de técnicas de biología molecular hemos aislado, clonado y secuenciado un segmento del gen codante de la actina de M. dubia. Asimismo, los análisis realizados muestran que el gen se expresa y presenta niveles similares de expresión en hojas, pulpa y cáscara de M. dubia. Sin embargo, es necesario realizar más experimentos a fin de verificar su estabilidad de expresión.

Abstract The authors describe a rare case of mycotic aneurysm (MA) associated with subarachnoid hemorrhage treated with aneurysm trapping. The literature on management and the surgical techniques are controversial due to lack of randomize trials.

Myrciaria dubia “camu-camu”, una especie nativa de la Amazonía que produce frutos con alto contenido de vitamina C y otras sustancias importantes. Sin embargo, los estudios moleculares de esta planta son escasos, por falta de un protocolo reproducible para purificar sus ácidos nucléicos. El objetivo de este trabajo fue establecer un protocolo para aislar el ADN genómico a partir de hojas de M. dubia, apropiado para análisis moleculares. El ADN se purificó con un protocolo modificado, la calidad y cantidad se estimó por espectrofotometría y electroforesis en gel de agarosa. Adicionalmente, la calidad se evaluó mediante RAPD. El ratio de calidad (A260/A280) promedio del ADN fue 1.9±0.1 y el espectro de absorción UV/Vis presentó un único pico de máxima absorbancia a 260nm. Mediante electroforesis el ADN fue íntegro y sin ARN. También, la síntesis de amplicones RAPD nos sugiere ausencia de inhibidores para polimerasas. La concentración promedio del ADN fue 99±33 ng/ml y el rendimiento promedio fue 237±80 mg ADN/g hoja. En conclusión, se ha establecido un protocolo de aislamiento de ADN genómico a partir de hojas de Myrciaria dubia “camu camu”, caracterizado por permitirnos obtener ADN de alta calidad y cantidad suficiente para análisis moleculares como el RAPD.

Ants are the most abundant group of soil arthropods in olive groves where they are involved in various trophic relationships of great importance for crops. The system of soil management is one agricultural practice that has a great effect on ants, so the objective of this study was to compare ant populations in organic olive orchards with a ground cover of natural vegetation and others where this natural vegetation is mechanically removed at the beginning of June. Ants were sampled using pitfall traps at 14, 30, 70 and 90 days after the removal of the ground vegetation. Overall, ant biodiversity did not change. However, changes were observed in the abundance of ant species, in particular, in those species that build shallow nests in the soil, both between the rows of trees and under the canopy of olive trees. In contrast, deep nesting species, such as Messor barbarus, were not affected. The response also differed between the various genera: the abundance of Cataglyphis increased, due to there being more of the species C. rosenhaueri, while there was a significant fall in Aphaenogaster, due to the decline in abundance of A. senilis. Thirty days after the removal of vegetation, the response of most of the genera was clearly noticeable, due to the increased activity of workers, and in some cases there were still differences after 90 days.

En este artículo se presenta la experiencia de repotenciación de un transformador de potencia de 20/25 MVA, 115/34,5 kV, Y/Y/D sumergido en aceite, al incrementar la potencia a 30/35 MVA. Después de un riguroso estudio se concluyó que la opción más eficiente consistía en rediseñar el transformador. Esta experiencia abarca los aspectos metodológicos, pruebas preliminares, rediseño del transformador y cambio del núcleo (construcción de los devanados principales y del devanado de compensación), pruebas finales en fábrica y validación de la metodología desarrollada. La implementación de la metodología se realizó a través de una herramienta computacional y la validación se realizó mediante ensayos en la planta de Industrias Explorer, Duitama, Colombia.

Lack of effectiveness of radiation therapy may arise from different factors such as radiation induced receptor tyrosine kinase activation and cell repopulation; cell capability to repair radiation induced DNA damage; high grade glioma (HGG) tumous heterogeneity, etc. In this study, we analyzed the potential of targeting epidermal growth factor receptor (EGFR) in inducing radiosensitivity in two human HGG cell lines (11 and 15) that displayed similar growth patterns and expressed the receptor protein at the cell surface. We found that 15 HGG cells that express more EGFR at the cell surface were more sensitive to AG556 (an EGFR inhibitor), compared to 11 HGG cells. Although in line 15 the effect of the inhibitor was greater than in line 11, it should be noted that the efficacy of this small-molecule EGFR inhibitor as monotherapy in both cell lines has been modest, at best. Our data showed a slight difference in the response to radiation of the HGG cell lines, three days after the treatment, with line 15 responding better than line 11. However, both cell lines responded to ionizing radiation in the same way, seven days after irradiation. EGFR inhibition induced radiosensitivity in 11 HGG cells, while, in 15 HGG cells, the effect of AG556 treatment on radiation response was almost nonexistent.

Antecedentes: La resistencia a rifampicina en M. tuberculosis involucra mutaciones en el gen rpoβ que codifica a la subunidad β de la ARN polimerasa. Objetivo: Identificar las mutaciones del gen rpoβ , en cepas de M. tuberculosis asociadas con resistencia a rifampicina aisladas de la Subregiσn de Salud Lima Norte, Perϊ. Materiales y métodos: Se cultivó en Lowestein - Jenseen 73 muestras de esputo de pacientes con tuberculosis pulmonar. A 62, con más de 10 colonias por tubo, se les comprobó susceptibilidad a isoniazida, rifampicina, estreptomicina y etambutol. Se realizó la extracción de ADN por PCR, clonación en el vector pGEM-T, transformación, selección de clonas recombinantes y secuenciamiento del ADN plasmídico para la determinación de los polimorfismos del gen rpoβ. Resultados: 52 (83,9%) cepas fueron resistentes a rifampicina (Rif r) y 10 (16,1%) susceptibles (Rif s ). Se encontró alteraciones en el gen rpoβ en 51 de 52 cepas Rif r Se identificaron 20 mutaciones. Las mutaciones mαs frecuentes fueron encontradas en los codones Ser-531 (62,7%), His-526 (15,7%), Asp-516 (11,8%) y Gln-513 (5,9%). No se observσ mutaciσn alguna en las 10 cepas Rif s. 94,2% de nuestras cepas Rif r fueron también resistentes a isoniazida. Conclusiones: Se encontraron mutaciones en el gen rpoB de casi todas las cepas Rif r ; asimismo, casi todas las cepas Rif r fueron también resistentes a isoniazida.

In this paper, an experience is presented showing repowering an oil-submerged power transformer. The most efficient option is the redesign and repowering a transformer 20/25 MVA, 115/34.5 kV, Y/Y/D to increase the power from 20 to 30/35 MVA. This experience considers methodological aspects, preliminary tests, redesign and construction of main winding and compensation winding; final tests factory and validation of the methodology were carried out. The implementation of the methodology was conducted through a computational tool and the validation was conducted by testing at the factory laboratory of Industries Explorer, Duitama, Colombia.

The olive is one of the most important crops grown in the Mediterranean region, both in terms of total surface area and its socioeconomic and environmental impact. In the present work, the main soil parameters of olive groves under different management systems are compared to an uncultivated area. Soil samples were collected and analysed from native vegetation (NV) and olive groves under three different soil management systems: conventional tillage (T), no-tillage bare soil (NT) and cover crop (CC). The groves (T, NT, and CC) increased the calcium carbonate content in the uppermost part of the soil profile with respect to NV. The lowest calcium carbonate concentrations were recorded in the top few centimetres of NV soil, with concentrations increasing with depth, while in the cultivated soils, no depth-related variations were found. The results showed an accumulation of soil organic carbon (SOC) in the shallowest soil layer resulting in a high stratification value in the NV; however, this diminished in the cultivated soil and particularly in the tilled plots. The plots under these types of soil management also presented the lowest SOC, nitrogen, potassium and C/N values. CC was the soil management system that showed the best soil properties. Our results indicate that using cover crops and eliminating tillage practices significantly improve soil quality in Mediterranean olive groves.El olivo es uno de los cultivos más importantes en la región mediterránea, tanto por la extensión que ocupa como por su impacto económico, social y medioambiental. En este trabajo se comparan los principales parámetros del suelo en un olivar bajo distintos manejos del suelo con un área natural donde no se ha implantado el cultivo. En concreto, se recogieron y analizaron muestras de suelo bajo vegetación nativa (NV), suelo de olivar labrado (T), parcelas en no laboreo con suelo desnudo (NT) y parcelas con cubierta vegetal espontánea (CC). El cultivo (T, NT y CC) incrementó el contenido de carbonato cálcico en los primeros centímetros. Las concentraciones más bajas se registraron en los primeros centímetros de la NV, donde además se observaron incrementos con la profundidad, mientras que en los suelos cultivados no se apreciaron diferencias con la profundidad. Los resultados mostraron una acumulación del carbono orgánico del suelo (SOC) en las capas más superficiales, que dio lugar a un valor de estratificación muy alto en NV y que disminuyó en los suelos cultivados, especialmente en los que recibieron un pase de labor. La parcela T presentó además los valores más bajos de SOC, nitrógeno (N), potasio (K) y relación C/N. Nuestros resultados indican cómo la implantación de cubierta vegetal mejoran significativamente la calidad del suelo en cultivos mediterráneos.O olival é uma das culturas mais importantes da região da bacia Mediterrânica, tanto pela superfície que ocupa como pelo seu impacto sócio-económico e ambiental. Neste trabalho comparam-se os principais parâmetros de um solo de olival sujeito a diferentes tipos de maneio com uma área natural não cultivada. Especificamente, recolheram- se e analisaram-se amostras de solo com vegetação nativa (NV) e de solo de olival sujeito a três diferentes tipos de maneio: lavoura convencional (T), não-lavoura com solo a descoberto (NT) e coberto vegetal espontâneo (CC). A presença de cultura (T, NT e CC) aumentou o teor de carbonato de cálcio nos primeiros centímetros de solo. As concentrações mais baixas foram registadas na camada superficial do solo NV, aumentando com a profundidade, enquanto que nos solos cultivados não foram encontradas quaisquer diferenças com o aumento da profundidade. Os resultados mostram uma acumulação de carbono orgânico do solo (SOC) nas camadas mais superficiais, resultando num elevado valor de estratificação em NV, que diminuiu nos solos cultivados, principalmente nas parcelas sujeitas a lavoura. A parcela T apresentou os menores valores de SOC, azoto, potássio e razão C/N. O CC foi a técnica de maneio do solo que contribuiu para as melhores propriedades do solo. Os resultados obtidos indicam que o uso de coberto vegetal, bem como a eliminação de práticas de lavoura melhoraram significativamente a qualidade do solo em olivais instalados na região da bacia Mediterrânica.

In a computer science curriculum, the data structures course is considered fundamental. In that course, students must generate the ability to desingn the more suitable data structures for a problem solution. They must also write an efficient algorithm in order to solve the problem. Students must understand that there are different types of data structures, each of them with associated algorithms of different complexity. A data structures laboratory is a set of computional tools that helps students in the experimentation with the concepts introduced in the curse. The main objetive of this experimentation is to generate the student's needed abilities for manipulating complex data structure. This paper presents the main characteristics of the laboratory built as a sopport of the course. we illustrate the huge possibilities of the tool with an example.