Plant Variety, Mycorrhization, and Herbivory Influence Induced Volatile Emissions and Plant Growth Characteristics in Tomato.

Plants produce a range of volatile organic compounds (VOCs) that mediate vital ecological interactions between herbivorous insects, their natural enemies, plants, and soil dwelling organisms including arbuscular mycorrhizal fungi (AMF). The composition, quantity, and quality of the emitted VOCs can vary and is influenced by numerous factors such as plant species, variety (cultivar), plant developmental stage, root colonization by soil microbes, as well as the insect developmental stage, and level of specialization of the attacking herbivore. Understanding factors shaping VOC emissions is important and can be leveraged to enhance plant health and pest resistance. In this greenhouse study, we evaluated the influence of plant variety, mycorrhizal colonization, herbivory, and their interactions on the composition of emitted volatiles in tomato plants (Solanum lycopersicum L.). Four tomato varieties from two breeding histories (two heirlooms and two hybrids), were used. Tomato plants were inoculated with a commercial inoculum blend consisting of four species of AMF. Plants were also subjected to herbivory by Manduca sexta (Lepidoptera: Sphingidae L.) five weeks after transplanting. Headspace volatiles were collected from inoculated and non-inoculated plants with and without herbivores using solid phase-microextraction. Volatile profiles consisted of 21 different volatiles in detectable quantities. These included monoterpenes, sesquiterpenes, and alkane hydrocarbons. We documented a strong plant variety effect on VOC emissions. AMF colonization and herbivory suppressed VOC emissions. Plant biomass was improved by colonization of AMF. Our results show that mycorrhization, herbivory and plant variety can alter tomato plant VOC emissions and further shape volatile-mediated insect and plant interactions.

Vivencias académicas y salud mental en tres cohortes universitarias bajo emergencia covid-19 / Academic experiences and mental health in three university cohorts under COVID-19 emergency

(analítico) La inesperada irrupción del covid-19 tuvo profundas consecuencias para los/las estudiantes universitarios, quienes se vieron forzados/as a desarrollar sus carreras remotamente. Particularmente en Chile, las cohortes de ingreso 2019, 2020 y 2021 conformaron un caso único debido a las diferentes condiciones bajo las cuales se produjo su incorporación. Esta investigación tuvo por fin determinar las diferencias y la relación entre las variables personales y las vivencias académicas en una muestra de 331 estudiantes ad-hoc. Los resultados obtenidos estadísticamente mediante una estrategia asociativa e inferencial permiten concluir que no existen diferencias entre cohortes respecto a su salud mental, salvo en la vivencia con la carrera entre 2020 y 2021. Se presentan sugerencias para su abordaje personal y académico, así como para el desarrollo de estrategias focalizadas en la salud mental universitaria.

(analytical) The unexpected irruption of COVID-19 had profound consequences for university students, who were forced to develop their careers remotely. Particularly in Chile, the 2019, 2020 and 2021 entry cohorts formed a unique case due to the different conditions under which their incorporation took place. This research aimed to determine the differences and the relationship between personal variables and academic experiences in a sample of 331 ad-hoc students. The results obtained statistically through an associative and inferential strategy, allow us to conclude that there are no differences between cohorts with respect to their mental health, except in the experience with the career between 2020 and 2021. Suggestions are presented for their personal and academic approach, as well as for the development of strategies focused on university mental health.

(analítico) A inesperada irrupção do Covid-19 teve consequências profundas para os estudantes universitários, que foram forçados a desenvolver as suas carreiras remotamente. Particularmente no Chile, as coortes de entrada de 2019, 2020 e 2021 foram únicas devido às diferentes condições sob as quais entra-ram. Esta investigação visava determinar as diferenças e a relação entre as variáveis pessoais e as experiências académicas numa amostra de 331 estudantes ad-hoc. Os resultados obtidos estatisticamente através de uma estratégia associativa e inferencial, permitemnos concluir que não existem diferenças entre os coortes no que respeita à sua saúde mental, excepto na experiência com a carreira entre 2020 e 2021. São apresentadas sugestões para abordagens pessoais e académicas, bem como para o desenvolvimento de estratégias centradas na saúde mental universitária.

Flooding and Herbivory Interact to Alter Volatile Organic Compound Emissions in Two Maize Hybrids.

Flooding is a major plant abiotic stress factor that is frequently experienced by plants simultaneously with other biotic stresses, including herbivory. How plant volatile emissions, which mediate interactions with a wide range of organisms, are influenced by flooding and by multiple co-occurring stress factors remains largely unexplored. Using Spodoptera frugiperda (Lepidoptera: Noctuidae) (fall armyworm) as the insect pest and two maize (Zea mays, L. Poaceae) hybrids differentially marketed for conventional and organic production, we assessed the effects of flooding, herbivory, and both stress factors on the composition of blends of emitted volatiles. Headspace volatiles were collected from all treatment combinations seven days after flooding. We documented metrics indicative of biomass allocation to determine the effects of individual and combined stressors on plant growth. We also evaluated relationships between volatile emissions and indicators of soil chemical characteristics as influenced by treatment factors. Flooding and herbivory induced the emission of volatile organic compounds (VOCs) in similar ways on both maize hybrids, but the interaction of both stress factors produced significantly larger quantities of emitted volatiles. Thirty-eight volatile compounds were identified, including green leaf volatiles, monoterpenes, an aldehyde, a benzoate ester, sesquiterpenes, a diterpene alcohol, and alkane hydrocarbons. The hybrid marketed for organic production was a stronger VOC emitter. As expected, plant biomass was detrimentally affected by flooding. Soil chemical properties were less responsive to the treatment factors. Taken together, the results suggest that flooding stress and the interactions of flooding and insect attack can shape the emission of plant volatiles and further influence insect-plant interactions.

Gerencia de diagnóstico y vigilancia epidemiológica del Instituto Nacional de Higiene "Rafael Rangel": Una década de avances y logros / Diagnostic and epidemiological surveillance management The National Institute of Hygiene "Rafael Rangel": A decade of advances and achievements

Buscando en los registros de las principales actividades de la Gerencia de Diagnóstico y Vigilancia Epidemiológica ha sido difícil elegir entre tantas vivencias, aquellos elementos que marcaron pauta durante la década 2008 ­ 2018. No obstante, es de resaltar que los desafíos afrontados ante la aparición de brotes, epidemias y la primera pandemia del siglo XXI, trajeron consigo un cúmulo de experiencias que se presentan en este artículo. Como centro nacional de referencia en las áreas de Bacteriología, Micología y Virología, continuamos aportando soluciones a la salud pública nacional mediante la actualización profesional de nuestro personal y la formación de la generación de relevo, en la que participan profesionales de excelencia, altamente especializados y sensibilizados con la problemática y los requerimientos de nuestra población. Asimismo, a través de la coordinación, supervisión y evaluación de la Red de laboratorios de salud pública, se contribuye con el fortalecimiento del diagnóstico de enfermedades transmisibles y vigilancia epidemiológica en el país. El trabajo realizado en estos diez años ha sido excelente, crucial y prioritario para enfrentar las emergencias. Debemos seguir trabajando en dos aspectos claves: 1. Mayor integración del laboratorio con el componente epidemiológico y clínico del país para ser más útiles al sistema de salud, y 2. Consolidar la creación del edificio sede del Centro de Diagnóstico de Enfermedades Transmisibles del Instituto Nacional de Higiene "Rafael Rangel" (INHRR), proyecto en el que estamos trabajando con la asesoría de la OPS/OMS.

Looking at the records of the main activities of the Diagnostic and Epidemiological Surveillance Management, it has been difficult to choose between many experiences, those elements that set the standard during the 2008 ­ 2018 decade. However, it is noteworthy that the challenges faced with the emergence of outbreaks, epidemics and the first pandemic of the 21st century, brought with it a wealth of experiences that are presented in this article. As a national reference center in Bacteriology, Mycology and Virology areas, we continue to provide solutions to public health through the professional updating of our staff and formation of the relief generation, in which participate professionals of excellence, highly specialized and sensitized with the problems and requirements of our population. Likewise, through the coordination, supervision and evaluation of the public health laboratories network, it contributes to the strengthening of the communicable diseases diagnosis and epidemiological surveillance in the country. The work done in these ten years has been excellent, crucial and priority to face emergencies. We must continue working on two key aspects: 1. Greater laboratory integration with the epidemiological and clinical component of the country to be more useful to the health system, and 2. Consolidate headquarters building creation of the National Institute of Hygiene "Rafael Rangel" (INHRR) Diagnostic Center for Communicable Diseases, project in which we are working with the PAHO / WHO advice.

Correction: Use of inverse modeling to evaluate CENTURY-predictions for soil carbon sequestration in US rain-fed corn production systems.

[This corrects the article DOI: 10.1371/journal.pone.0172861.].

Use of inverse modeling to evaluate CENTURY-predictions for soil carbon sequestration in US rain-fed corn production systems.

We evaluated the accuracy and precision of the CENTURY soil organic matter model for predicting soil organic carbon (SOC) sequestration under rainfed corn-based cropping systems in the US. This was achieved by inversely modeling long-term SOC data obtained from 10 experimental sites where corn, soybean, or wheat were grown with a range of tillage, fertilization, and organic matter additions. Inverse modeling was accomplished using a surrogate model for CENTURY's SOC dynamics sub-model wherein mass balance and decomposition kinetics equations from CENTURY are coded and solved by using a nonlinear regression routine of a standard statistical software package. With this approach we generated statistics of CENTURY parameters that are associated with the effects of N fertilization and organic amendment on SOC decay, which are not as well quantified as those of tillage, and initial status of SOC. The results showed that the fit between simulated and observed SOC prior to inverse modeling (R2 = 0.41) can be improved to R2 = 0.84 mainly by increasing the rate of SOC decay up to 1.5 fold for the year in which N fertilizer application rates are over 200 kg N ha-1. We also observed positive relationships between C inputs and the rate of SOC decay, indicating that the structure of CENTURY, and therefore model accuracy, could be improved by representing SOC decay as Michaelis-Menten kinetics rather than first-order kinetics. Finally, calibration of initial status of SOC against observed levels allowed us to account for site history, confirming that values should be adjusted to account for soil condition during model initialization. Future research should apply this inverse modeling approach to explore how C input rates and N abundance interact to alter SOC decay rates using C inputs made in various forms over a wider range of rates.

Estudio comparativo de la sensibilidad entre el cultivo y la reacción en cadena de la polimerasa para la detección de bordetella pertussis a partir de muestras de hisopado nasofaríngeo / Comparative study of culture and sensitivity polymerase chain reaction in the diagnosis of bordetella pertussis from nasopharyngeal swab specimens

La tosferina es una enfermedad infecciosa causada por Bordetella pertussis, que se diagnostica mediante el cultivo como técnica de referencia, la cual tiene como limitante una baja sensibilidad. Es debido a esto, que el presente trabajo se centró en evaluar a la técnica de PCR a punto final amplificando las secuencias IS481 y PT, como una metodología alternativa diagnóstica a partir de 100 muestras pareadas de hisopado nasofaríngeo de pacientes provenientes de distintas regiones de Venezuela. Dichas muestras pareadas constaron de un hisopado para realizar el cultivo bacteriano y el otro para la detección de ADN específico. La identificación microbiológica de B. pertussis incluyó el aislamiento del microorganismo en agar Regan-Lowe, identificación bioquímica y la confirmación por coaglutinación. El análisis de los resultados fue realizado empleando el programa SPSS 21.0.0., usando como herramienta estadística el test de McNemar. La sensibilidad obtenida por el protocolo de PCR a punto final fue 50%, en concordancia con reportes previos. De acuerdo al valor de p=0,002 obtenido, la detección de B. pertussis mediante los dos métodos presentó una diferencia para el diagnóstico de tosferina estadísticamente significativa, por lo que no es indiferente emplear ambas técnicas diagnósticas. Sin embargo, se recomienda emplear en forma combinada ambas metodologías para incrementar la probabilidad de realizar el diagnóstico.

Whooping cough is an infectious disease caused by Bordetella pertussis, diagnosed by culture as a reference technique, which has low sensitivity as limiting. It is because of this that the present work focused on evaluating the PCR technique endpoint amplifying IS481 and PT sequences, as an alternative methodology diagnostic from 100 paired samples of nasopharyngeal swabs from patients from different regions of Venezuela. Such paired samples comprised a swab for bacterial culture and the other for detection of specific DNA. Microbiological identification of B. pertussis included the isolation of the microorganism in agar Regan-Lowe, biochemical identification and confirmation by Coagglutination. The analysis of the results was performed using the SPSS program 21.0.0., as a statistical tool using the McNemar test. The sensitivity obtained by the PCR protocol endpoint was 50%, consistent with previous reports. According to the value of p = 0.002 obtained, detection of B. pertussis by the two methods showed a difference for the diagnosis of pertussis statistically significant, so it is not indifferent both diagnostic techniques employed. However, it is recommended to use both methods in combination to increase the likelihood of diagnosis.

Electroforesis de campo eléctrico pulsado en la tipificación molecular de cepas aisladas de un brote de Salmonelosis ocasionado por consumo de queso contaminado con Salmonella Javiana / Pulse Field Gel Electrophoresis in molecular typification of strains isolated from a Salmonellosis outbreak caused by consumption of Salmonella Javiana contaminated cheese

El objetivo de este trabajo fue confirmar por Electroforesis de Campo Electrico Pulsado (PFGE) que la Salmonella aislada del alimento implicado en el brote (queso blanco) fue la responsable del evento.La muestra de queso blanco presento elevado recuento de coliformes, E. coli y S. aureus,ademas, presencia de Salmo nella spp., lo que indico condiciones sanitarias inadecuadas y posible contaminacion de origen fecal. Para la confirmacion de las cepas sospechosas de Sal monella spp, aisladas de los pacientes y del alimento, se utilizaron tecnicas bioquimicas convencionales, la serotipificacion se realizo siguiendo el esquema de White-kauffmann-LeMinor y la sensibilidad a los antimicrobianos (Ampicilina, Trimetroprim-Sulfametoxazole, Ciprofloxacina, Amoxicilina, Ac.Clavulanico, Cloranfenicol, Ceftriaxone y Tetraciclina) por la tecnica kirby-Bauer. Las cepas bacterianas de Salmonella spp aisladas fueron identificadas como Salmonella Javiana [1,9,12:l, z28:1,5] y resultaron sensibles a todos los antibioticos probados.La Tipificacion Molecular de las cepas, se realizo por PFGE, se gun protocolo estandarizado de PulseNet para Salmonella y el analisis de los patrones se estudio utilizando el programa BioNumerics, version 4.0, lo cual mostro que los aisla dos de Salmonella Javiana procedentes tanto de pacientes como del alimento tenian identico patron de restriccion, en tamano y numero de fragmentos. La ocurrencia de un patron unico de PFGE (Coeficiente de similitud 100%) entre los aislados permitio demostrar que el queso contaminado con Salmonella Javiana fue el responsable del brote familiar.

The aim of this work was confirmation through Pulse Field Gel Electrophoresis (PFGE) that Salmonella isolated from the food implicated in the outbreak (white cheese) was responsible for the event. The white cheese sample showed a high count of Coli orms,f E. coli and S. aureus. Moreover, Salmonella was pre ent,s which indicated inadequate sanitary conditions and possible fecal contamination. The suspected Salmonella strains isolated from patients and the food sample, were confirmed using conventional biochemical techniques, serotyping according to the White-kauffmann-Le Minor scheme and antibiotics sensibility (Am picillin, Trimetroprim-Sulfametoxazole, Ciprofloxacin, Amoxicillin, Clavulanic Acid, Cloranfenicol, Ceftriaxone and tetraciclin) following kirby-Bauer’s technique. The Salmonella strains were identified as Salmonella Javiana [1,9,12:I, z28:1,5]and were sensitive to all the antibiotics tested. The molecular typing of the strains was performed using PFGE, according to the PulseNet standardized protocol for Salmonella. The pattern analysis was studied using Bionunella merics program, version 4.0, which showed that the Sal monella Javiana isolates from patients as the food sample had an identical restriction pattern in size and fragments number. The incidence of a unique pattern of PFGE (similarity coefficient 100%) between isolates demonstrated that the cheese contaminated with Salmonella Javiana was responsible for the family outbreak.

Influence of water content on structure and mobility of polyvinyl alcohol: a molecular dynamics simulation.

Fully atomistic molecular dynamics simulations have been performed on aqueous solutions of polyvinyl alcohol (PVA) to get some insight into the effect of water content on PVA structure and dynamics. Simulations were carried out on mixtures of water/atactic PVA at 300 K covering a composition range (water weight fraction X(w)=0.1-0.8. The analysis focuses on polymer segmental dynamics, which is monitored by the mean square displacement, Van Hove self correlation function, non-Gaussian parameter, and the intermediate incoherent scattering function. It was found that PVA dynamics is strongly affected by addition of water. Both, PVA carbon and hydrogen (hydroxyl and main chain hydrogens) motions are faster with further dilution. Differences on atom mobility (dynamic heterogeneity) decreases as water content increases allowing more isotropic segmental motions. Moreover, the non-Gaussian parameter shows a maximum at X(w)=0.25 followed by a continuous decrease with dilution. The non-Gaussian effects become more important as the water content decreases and dynamic heterogeneity is enhanced. These results are explained in terms of the plasticization effects of water on the polymer and the intrinsic dynamic heterogeneity observed on PVA dynamics.

First isolation of a VIM-producing Klebsiella pneumoniae from a seven-year-old child in Venezuela.

BACKGROUND: VIM-type metallo-betalactamases (MBLs) exhibit hydrolytic activity against most betalactam antibiotics, including carbapenems. So far, VIM-type-producing Klebsiella pneumoniae isolates had not been reported in Latin America. METHODOLOGY: In July 2005, a carbapenem-resistant Klebsiella pneumoniae was isolated from a urine sample collected from a 7-year-old girl hospitalized at the Hospital de Niños "J. M. de los Ríos" in Caracas, Venezuela. This strain was identified using conventional biochemical tests. The susceptibility analysis was conducted by disk diffusion, and MICs for Imipenem and Meropenem were performed by agar dilution. For the phenotypic detection of MBL we used the Imipenem-EDTA/SMA double-disk diffusion method. The hydrolytic activity against carbapenems was determined by the Masuda microbiological method. Purified protein was subjected to isoelectric focusing (IEF). Detection of antimicrobial resistance genes was performed by PCR amplification with specific VIM primers. RESULTS: The strain showed resistance to most betalactam antibiotics, quinolones and amynoglicosides, but remained susceptible to Aztreonam and Cefepime. The use of phenotypic and microbiological methods detected the presence of a metallobetalactamase. By IEF we visualized three bands at pI 5.4, 7.6 and 7.9, corresponding to reduced-spectrum betalactamases, and a band at pI 5.8 that corresponded to the metallobetalactamase. PCR screening of bla genes revealed the presence of blaVIM, with an amplicon of 261 bp. CONCLUSIONS: This is the first report of a MBL-mediated carbapenem-resistant Klebsiella pneumoniae in Latin America, which constitutes a public health concern in our region since their transference to other microorganisms with multiple antibiotic resistance mechanisms will increase the antimicrobial resistance problem.

Reduced susceptibility to quinolones among Salmonella serotypes isolated from poultry at slaughter in Venezuela.

Today there are recognized global "hot spots" that are areas in which nontyphoid Salmonella serotypes have been reported to have a high prevalence of quinolone resistance. There is concern that resistant strains can be disseminated from these localized geographical areas by travelers or via commercial food products. The objective of this article is to report a high frequency of reduced susceptibility to first- and second-generation quinolones among nontyphoid Salmonella isolates from poultry at slaughter in two processing plants belonging to the largest poultry integration companies in Zulia State, Venezuela. Nearly all (74 of 77; 96.1%) of the isolated strains were resistant to nalidixic acid, and 3.7% were resistant to ciprofloxacin; most (45 of 77; 58%) exhibited reduced susceptibility to ciprofloxacin and norfloxacin (15 of 77; 19.5%). In contrast, all of the isolates were susceptible to beta-lactamic antimicrobial drugs. Ninety-three percent (72 of 77) of the isolates were either Salmonella Parathyphi B or Salmonella Heidelberg, which have been reported as invasive Salmonella. The predominant serotypes in each slaughter plant showed different antimicrobial susceptibilities, only having in common their high resistance to nalidixic acid, suggesting that different clones disseminated in each commercial integration. The detection of high frequency of reduced susceptibility to first- and second-generation quinolones among nontyphoid Salmonella isolates from fresh poultry during processing is noteworthy. Resistance to quinolone drugs will not only make antimicrobial therapy more complicated if foodborne disease results, but also these quinolone-resistant strains can disseminate from this local hot spot to other geographical areas, spreading the resistance against this important antimicrobial drug.

Relevance of functional neuroimaging in the progression of mild cognitive impairment.

AIM: To assess whether combining neuropsychological tests and cerebral blood flow markers improves progression accuracy from mild cognitive impairment (MCI) to Alzheimer's disease (AD) than each of them on its own. METHODS: Forty-two patients were investigated prospectively, undergoing baseline and 3-year follow-up neuropsychological tests and neuroimaging with Tc-ECD-SPECT. Twenty-one patients had developed AD while 21 retained their initial diagnosis. The relative blood flow and cognitive differences were studied. Validity parameters, multivariant analysis and logistic regression model were calculated. RESULTS: Patients who deteriorated showed lower scoring than stable subjects in some neuropsychological tests (p = 0.03-0.001) and in relative blood flow in selected regions (8-10%). Low cognitive test scoring and low relative blood flow in some regions showed sensibilities and specificities from 70% to 86% for the diagnosis of early Alzheimer's disease. The relative risk of progression to AD was up to 4.7 times higher for these patients (p = 0.0001). The left frontal relative blood flow, the CAMCOG and orientation scoring were the best data to predict the risk of progression to AD. CONCLUSIONS: The combination of functional imaging and neuropsychological tests can diagnose with high sensitivity and specificity if a patient is suffering cognitive impairment in its early stages, and may aid in predicting the risk of developing dementia.

Regional cerebral blood flow assessed with 99mTc-ECD SPET as a marker of progression of mild cognitive impairment to Alzheimer's disease.

Patients diagnosed with mild cognitive impairment (MCI) have a higher risk of developing Alzheimer's disease (AD). However, not all such patients develop this kind of dementia. The purpose of this prospective study was to assess whether regional cerebral blood flow (rCBF) patterns measured with technetium-99m ethyl cysteinate dimer single-photon emission tomography ((99m)Tc-ECD SPET) in patients suffering from MCI are useful in predicting progression to AD. The study group comprised 42 patients who fulfilled MCI criteria according to the International Psychogeriatric Association and the Alzheimer's Disease Cooperative Study. rCBF was calculated in 16 regions of interest (ROIs). All patients were clinically assessed for 1-3 years. Twenty-one developed AD (group I) while the initial diagnosis of MCI was retained in the other 21 (group II). ROC curves were designed, and sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were determined for each ROI. Compared with group II (MCI), group I (AD) showed a significant reduction of relative blood flow (RBF), ranging from 7% to 10%, in the following areas: right and left prefrontal, right and left frontal, right and left parietal, right and left temporal, right and left frontoparietotemporal and left posterior lateral temporal. Left prefrontal, left frontal and left parietal areas showed sensitivities and specificities higher than 75% and areas below the ROC curve close to 80%. This study shows that RBF patterns in the right and left prefrontal, right and left frontal and left parietal areas are sensitive early markers of progression towards AD. Reduction of rCBF in the medial temporal and anterior lateral temporal cortex has no value as a predictor since it also occurs in patients with MCI who remain stable.