Diversity of yeasts associated with wood and the gut of wood-feeding insects

The gut of insects and plant tissues are productive sources for the isolation of undescribed species of yeasts. In particular, the gut of lignicolous insects is colonized by yeasts that can carry out the fermentation of several sugars. The consistent association between xylose-fermenting (X-F) yeasts and the gut of lignicolous insects has been used as evidence of a symbiotic relationship between them. In general passalid beetles (Passalidae) and wood-roaches (Cryptocercidae) feed on rotted wood where they spend most of their lives. Digestion of the substrate depends on the symbiotic microbiota, which include strict and facultative anaerobic microorganisms such as bacteria, parabasalids, and fungi. The objectives of this study were to describe the yeasts associated with hardwoods in Louisiana (Chapter 2), the gut of the wood roach Cryptocercus collected in the Appalachian Mountains (Chapter 3), passalids collected in Guatemala (Chapter 4) and in Thailand (Chapter 5), and to study selection acting on xylose reductase (XR) in yeasts (Chapter 6). This study confirmed the routine presence of ascomycete yeasts from the clades Scheffersomyces, Spathaspora, Lodderomyces, and Sugiyamaella in the guts of wood roaches and passalid beetles, as well as basidiomycete yeasts in the genera Cryptococcus and Trichosporon in passalids exclusively. In this investigation, four new X-F yeasts, Scheffersomyces illinoinensis, Sc. quercinus, Sc. virginianus, and Sc. cryptocercus, were proposed based on multilocus phylogenetic analyses, molecular, and biochemical characterization. The X-F yeasts in the Scheffersomyces clade were the most abundant species in the gut of both wood-roaches and Guatemalan passalids, results that support and expand the previously described relationship between X-F yeasts and lignicolous insects. This finding, however, was not observed in Thai passalids, where the most abundant yeasts were closely related to Candida insectamans (Spathaspora clade) that does not ferment xylose. In addition, this study determined that the gut of lignicolous insects is a niche rich in undescribed yeasts classified in several clades. The xylose reductase gene (XYL1) has been shown to be useful as a molecular marker for rapid identification of cryptic yeast species, and the xylose reductase enzyme (XR) has been exposed to purifying selection in ascomycete yeasts

Isolation and molecular characterization of the Romaine lettuce phylloplane mycobiome

Romaine lettuce (Lactuca sativa) is an important staple of American agriculture. Unlike many vegetables, romaine lettuce is typically consumed raw. Phylloplane microbes occur naturally on plant leaves; consumption of uncooked leaves includes consumption of phylloplane microbes. Despite this fact, the microbes that naturally occur on produce such as romaine lettuce are for the most part uncharacterized. In this study, we conducted culture-based studies of the fungal romaine lettuce phylloplane community from organic and conventionally grown samples. In addition to an enumeration of all such microbes, we define and provide a discussion of the genera that form the “core” romaine lettuce mycobiome, which represent 85.5% of all obtained isolates: Alternaria, Aureobasidium, Cladosporium, Filobasidium, Naganishia, Papiliotrema, Rhodotorula, Sampaiozyma, Sporobolomyces, Symmetrospora and Vishniacozyma. We highlight the need for additional mycological expertise in that 23% of species in these core genera appear to be new to science and resolve some taxonomic issues we encountered during our work with new combinations for Aureobasidiumbupleuri and Curvibasidium nothofagi. Finally, our work lays the ground for future studies that seek to understand the effect these communities may have on preventing or facilitating establishment of exogenous microbes, such as food spoilage microbes and plant or human pathogens

Congenital Chagas’ disease transmission in the United States: Diagnosis in adulthood

Two brothers with congenitally-acquired Chagas’ disease (CD) diagnosed during adulthood are reported. The patients were born in the USA to a mother from Bolivia who on subsequent assessment was found to be serologically positive for Trypanosoma cruzi. Serologic screening of all pregnant women who migrated from countries with endemic CD is strongly recommended

Characterization of novel genic SSR markers in Linum usitatissimum (L.) and their transferability across eleven Linum species

Little is known about the evolutionary relationships among Linum species, basically because of the lack of transferable molecular markers. Currently, expressed sequence tags available in public databases provide an opportunity for the rapid and inexpensive development of simple sequence repeat (SSR) markers in wild flax species. In this regard, fifty expressed sequence tag-derived microsatellite markers (EST-SSRs) were evaluated for polymorphism and transferability in 50 Linum usitatissimum cultivars/accessions and 11 Linum species. Among them 23 EST-SSRs were polymorphic in L. usitatissimum, while 2-4 alleles were detected (average 2.26 per locus). The polymorphism information content value ranged from 0.08 to 0.55 (average 0.38). Forty one genic markers (95.3%) produced strong amplicons in at least two of the 11 Linum species. The percentage of cross amplification ranged from 34.1% to 92.7% in L. tauricum and L. bienne, respectively. Moreover, the rate of transferability was associated positively with the botanical section. Our results suggest that the high degree of EST-SSRs transferability to Linum species can be a useful enhancement of the current database of SSR markers for future genetic and evolutionary studies

Aplicaci?n de t?cnicas de Machine Learning para identificar factores de predicci?n del estado de las cotizaciones en el sector de maquinaria ligera

En el presente estudio haremos uso de Machine learning, usando 4 t?cnicas en la categor?a de aprendizaje supervisado, para la predicci?n del estado de las cotizaciones, buscando agilizar la toma de decisiones con respecto al tiempo y costos de importaci?n, y evitar la p?rdida de ventas. Para la construcci?n del modelo predictivo se inici? con la recopilaci?n y limpieza de datos. Posteriormente, se utiliz? el 80 % de datos recopilados para el entrenamiento de los modelos y 20% para la evaluaci?n de las predicciones. Con la t?cnica k-NN se obtuvo un accuracy del 67.9% con un par?metro de k = 5; con la t?cnica Regresi?n log?stica, se obtuvo un 70.69% de accuracy; con la t?cnica SVM se obtuvo un 63.79% de accuracy y con la t?cnica ?rbol de decisi?n se obtuvo un accuracy de 87.93%. Se aplic? codificaci?n y normalizaci?n como mejora a la base de datos y con ello, la t?cnica de ?rbol de decisi?n obtuvo el valor m?s alto de accuracy - 88.79%. Se recomienda el empleo de t?cnicas adicionales de Aprendizaje Supervisado a fin de seleccionar la que mejor resultado obtenga en la predicci?n

Enabling Space Exploration Medical System Development Using a Tool Ecosystem

The NASA Human Research Program's (HRP) Exploration Medical Capability (ExMC) Element is utilizing a Model Based Systems Engineering (MBSE) approach to enhance the development of systems engineering products that will be used to advance medical system designs for exploration missions beyond Low Earth Orbit. In support of future missions, the team is capturing content such as system behaviors, functional decompositions, architecture, system requirements and interfaces, and recommendations for clinical capabilities and resources in Systems Modeling Language (SysML) models. As these products mature, SysML models provide a way for ExMC to capture relationships among the various products, which includes supporting more integrated and multi-faceted views of future medical systems. In addition to using SysML models, HRP and ExMC are developing supplementary tools to support two key functions: 1) prioritizing current and future research activities for exploration missions in an objective manner; and 2) enabling risk-informed and evidence-based trade space analysis for future space vehicles, missions, and systems. This paper will discuss the long-term HRP and ExMC vision for the larger ecosystem of tools, which include dynamic Probabilistic Risk Assessment (PRA) capabilities, additional SysML models, a database of system component options, and data visualizations. It also includes a review of an initial Pilot Project focused on enabling medical system trade studies utilizing data that is coordinated across tools for consistent outputs (e.g., mission risk metrics that are associated with medical system mass values and medical conditions addressed). This first Pilot Project demonstrated successful operating procedures and integration across tools. Finally, the paper will also cover a second Pilot Project that utilizes tool enhancements such as medical system optimization capabilities, post-processing, and visualization of generated data for subject matter expert review, and increased integration amongst the tools themselves

Accurate Real-Time PCR Strategy for Monitoring Bloodstream Parasitic Loads in Chagas Disease Patients

Infection with the parasite Trypanosoma cruzi (T. cruzi), causing American trypanosomiasis or Chagas disease, remains a major public health concern in 21 endemic countries of America, with an estimated prevalence of 8 million infected people. Chagas disease shows a variable clinical course, ranging from asymptomatic to chronic stages with low parasitaemias, whose severest form is heart disease. Diagnosis at the asymptomatic and chronic stages is based on serological detection of anti-T. cruzi antibodies, because conventional parasitological methods lack sensitivity. Current chemotherapies are more effective in recent infections than in the chronic adult population. The criterion of cure relies on serological conversion to negative, which may occur only years after treatment, requiring long-term follow-up. In this context, we aimed to develop a real-time PCR assay targeted to repetitive sequences of T. cruzi for sensitive quantitation of parasitic load in peripheral blood of infected patients. It was applied to monitor treatment response of infected children, allowing rapid evaluation of drug efficacy as well as detection of treatment failure. It was also used for early diagnosis of chagasic reactivation in end-stage heart disease patients who received immunosuppressive drugs after cardiac transplantation. This laboratory strategy may constitute a novel parasitological tool for prompt and sensitive evaluation of anti-parasitic treatment of Chagas disease

Multilocus Phylogenetic Study of the Scheffersomyces Yeast Clade and Characterization of the N-Terminal Region of Xylose Reductase Gene

Many of the known xylose-fermenting (X-F) yeasts are placed in the Scheffersomyces clade, a group of ascomycete yeasts that have been isolated from plant tissues and in association with lignicolous insects. We formally recognize fourteen species in this clade based on a maximum likelihood (ML) phylogenetic analysis using a multilocus dataset. This clade is divided into three subclades, each of which exhibits the biochemical ability to ferment cellobiose or xylose. New combinations are made for seven species of Candida in the clade, and three X-F taxa associated with rotted hardwood are described: Scheffersomyces illinoinensis (type strain NRRL Y-48827T  =  CBS 12624), Scheffersomyces quercinus (type strain NRRL Y-48825T  =  CBS 12625), and Scheffersomyces virginianus (type strain NRRL Y-48822T  =  CBS 12626). The new X-F species are distinctive based on their position in the multilocus phylogenetic analysis and biochemical and morphological characters. The molecular characterization of xylose reductase (XR) indicates that the regions surrounding the conserved domain contain mutations that may enhance the performance of the enzyme in X-F yeasts. The phylogenetic reconstruction using XYL1 or RPB1 was identical to the multilocus analysis, and these loci have potential for rapid identification of cryptic species in this clade