Two in one: cryptic species discovered in biological control agent populations using molecular data and crossbreeding experiments

There are many examples of cryptic species that have been identified through DNA-barcoding or other genetic techniques. There are, however, very few confirmations of cryptic species being reproductively isolated. This study presents one of the few cases of cryptic species that has been confirmed to be reproductively isolated and therefore true species according to the biological species concept. The cryptic species are of special interest because they were discovered within biological control agent populations. Two geographically isolated populations of Eccritotarsus catarinensis (Carvalho) [Hemiptera: Miridae], a biological control agent for the invasive aquatic macrophyte, water hyacinth, Eichhornia crassipes (Mart.) Solms [Pontederiaceae], in South Africa, were sampled from the native range of the species in South America. Morphological characteristics indicated that both populations were the same species according to the current taxonomy, but subsequent DNA analysis and breeding experiments revealed that the two populations are reproductively isolated. Crossbreeding experiments resulted in very few hybrid offspring when individuals were forced to interbreed with individuals of the other population, and no hybrid offspring were recorded when a choice of mate from either population was offered. The data indicate that the two populations are cryptic species that are reproductively incompatible. Subtle but reliable diagnostic characteristics were then identified to distinguish between the two species which would have been considered intraspecific variation without the data from the genetics and interbreeding experiments. These findings suggest that all consignments of biological control agents from allopatric populations should be screened for cryptic species using genetic techniques and that the importation of multiple consignments of the same species for biological control should be conducted with caution

On The Power of Tree Projections: Structural Tractability of Enumerating CSP Solutions

The problem of deciding whether CSP instances admit solutions has been deeply studied in the literature, and several structural tractability results have been derived so far. However, constraint satisfaction comes in practice as a computation problem where the focus is either on finding one solution, or on enumerating all solutions, possibly projected to some given set of output variables. The paper investigates the structural tractability of the problem of enumerating (possibly projected) solutions, where tractability means here computable with polynomial delay (WPD), since in general exponentially many solutions may be computed. A general framework based on the notion of tree projection of hypergraphs is considered, which generalizes all known decomposition methods. Tractability results have been obtained both for classes of structures where output variables are part of their specification, and for classes of structures where computability WPD must be ensured for any possible set of output variables. These results are shown to be tight, by exhibiting dichotomies for classes of structures having bounded arity and where the tree decomposition method is considered

Effect of the harvest season on phenolic composition and oenological parameters of grapes and wines cv. Touriga Nacional (Vitis vinifera L.) produced under tropical semi-arid climate, in the state of Pernambuco, Brazil

The northeastern region of São Francisco Valley is the third largest wine producer in Brazil, differentiated by the production of at least two harvests per year, generally in the first and second semesters, respectively. The productive cycle of the vine in the first semester is higher than in the second semester, mainly due to differences in temperature, with maximum and average temperatures of approximately 30 ºC and 26 ºC, respectively. Second semester is characterized by higher temperatures (summer season) and that promote a rapid maturation of the grapes. The objective of this work was to evaluate the phenolic composition, other oenological parameters and the sensorial profile of grapes and wines of cv. 'Touriga Nacional' (Vitis vinifera L.), characterizing grapes and wines from four harvest seasons, two of them referring to the first half of the year and two referring to the second half of the year, using a broad analytical approach. The experimental design consisted of three randomized blocks, with sixty plants marked in different lines and positions (twenty plants in each block at the beginning, middle and end of the vineyard). The results showed that there was a harvesting effect for some of the grape chemical compounds (monomeric anthocyanins, organic acids, condensed tannins and monomeric flavanols, for example) as well as in wines (calcium, monomeric anthocyanins, condensed tannins and monomeric flavanols). Regarding the sensorial profile of the wines, it was possible to observe that higher scores were attributed to floral aroma in wines from the first harvest (first half of the year). Fruity, spice and empyreumatic aromas were higher in wines from second harvest season (second half of the year). For other attributes, there was a tendency for higher variations between the period of study (2014 – 2017) than between the harvest seasonsinfo:eu-repo/semantics/publishedVersio

A join-based hybrid parameter for constraint satisfaction

We propose joinwidth, a new complexity parameter for the Constraint Satisfaction Problem (CSP). The definition of joinwidth is based on the arrangement of basic operations on relations (joins, projections, and pruning), which inherently reflects the steps required to solve the instance. We use joinwidth to obtain polynomial-time algorithms (if a corresponding decomposition is provided in the input) as well as fixed-parameter algorithms (if no such decomposition is provided) for solving the CSP. Joinwidth is a hybrid parameter, as it takes both the graphical structure as well as the constraint relations that appear in the instance into account. It has, therefore, the potential to capture larger classes of tractable instances than purely structural parameters like hypertree width and the more general fractional hypertree width (fhtw). Indeed, we show that any class of instances of bounded fhtw also has bounded joinwidth, and that there exist classes of instances of bounded joinwidth and unbounded fhtw, so bounded joinwidth properly generalizes bounded fhtw. We further show that bounded joinwidth also properly generalizes several other known hybrid restrictions, such as fhtw with degree constraints and functional dependencies. In this sense, bounded joinwidth can be seen as a unifying principle that explains the tractability of several seemingly unrelated classes of CSP instances

Investigating hyper-vigilance for social threat of lonely children

The hypothesis that lonely children show hypervigilance for social threat was examined in a series of three studies that employed different methods including advanced eye-tracking technology. Hypervigilance for social threat was operationalized as hostility to ambiguously motivated social exclusion in a variation of the hostile attribution paradigm (Study 1), scores on the Children’s Rejection-Sensitivity Questionnaire (Study 2), and visual attention to socially rejecting stimuli (Study 3). The participants were 185 children (11 years-7 months to 12 years-6 months), 248 children (9 years-4 months to 11 years-8 months) and 140 children (8 years-10 months to 12 years-10 months) in the three studies, respectively. Regression analyses showed that, with depressive symptoms covaried, there were quadratic relations between loneliness and these different measures of hypervigilance to social threat. As hypothesized, only children in the upper range of loneliness demonstrated elevated hostility to ambiguously motivated social exclusion, higher scores on the rejection sensitivity questionnaire, and disengagement difficulties when viewing socially rejecting stimuli. We found that very lonely children are hypersensitive to social threat

Rudimentary G-Quadruplex-Based Telomere Capping In Saccharomyces Cerevisiae

Telomere capping conceals chromosome ends from exonucleases and checkpoints, but the full range of capping mechanisms is not well defined. Telomeres have the potential to form G-quadruplex (G4) DNA, although evidence for telomere G4 DNA function in vivo is limited. In budding yeast, capping requires the Cdc13 protein and is lost at nonpermissive temperatures in cdc13-1 mutants. Here, we use several independent G4 DNA-stabilizing treatments to suppress cdc13-1 capping defects. These include overexpression of three different G4 DNA binding proteins, loss of the G4 DNA unwinding helicase Sgs1, or treatment with small molecule G4 DNA ligands. In vitro, we show that protein-bound G4 DNA at a 3\u27 overhang inhibits 5\u27-\u3e 3\u27 resection of a paired strand by exonuclease I. These findings demonstrate that, at least in the absence of full natural capping, G4 DNA can play a positive role at telomeres in vivo

Extracts of Phenolic Compounds from Seeds of Three Wild Grapevines—Comparison of Their Antioxidant Activities and the Content of Phenolic Compounds

Phenolic compounds were extracted from three wild grapevine species: Vitis californica, V. riparia and V. amurensis seeds using 80% methanol or 80% acetone. The total content of phenolic compounds was determined utilizing the Folin-Ciocalteu’s phenol reagent while the content of tannins was assayed with the vanillin and BSA precipitation methods. Additionally, the DPPH free radical scavenging activity and the reduction power of the extracts were measured. The RP-HPLC method was applied to identify the phenolic compounds in the extracts, such as phenolic acids and catechins. The seeds contained large amounts of tannins, catechins and gallic acid and observable quantities of p-coumaric acid. The total content of phenolic compounds and tannins was similar in the extracts from V. californica and V. riparia seeds. However, the total content of total phenolic compounds and tannins in the extracts from V. californica and V. riperia seeds were about two-fold higher than that in the extracts from V. amurensis seeds. Extracts from seeds of the American species (V. californica and V. riparia) contained similarly high concentrations of tannins, whereas extracts from seeds of V. amurensis had approximately half that amount of these compounds. The content of catechin and epicatechin was similar in all extracts. The highest DPPH• anti-radical scavenging activity was observed in the acetonic and methanolic extracts of V. californica and V. riparia seeds— while the acetonic extract from the V. californica seeds was the strongest reducing agent

Genetic Engineering of Trypanosoma (Dutonella) vivax and In Vitro Differentiation under Axenic Conditions

Trypanosoma vivax is one of the most common parasites responsible for animal trypanosomosis, and although this disease is widespread in Africa and Latin America, very few studies have been conducted on the parasite's biology. This is in part due to the fact that no reproducible experimental methods had been developed to maintain the different evolutive forms of this trypanosome under laboratory conditions. Appropriate protocols were developed in the 1990s for the axenic maintenance of three major animal Trypanosoma species: T. b. brucei, T. congolense and T. vivax. These pioneer studies rapidly led to the successful genetic manipulation of T. b. brucei and T. congolense. Advances were made in the understanding of these parasites' biology and virulence, and new drug targets were identified. By contrast, challenging in vitro conditions have been developed for T. vivax in the past, and this per se has contributed to defer both its genetic manipulation and subsequent gene function studies. Here we report on the optimization of non-infective T. vivax epimastigote axenic cultures and on the process of parasite in vitro differentiation into metacyclic infective forms. We have also constructed the first T. vivax specific expression vector that drives constitutive expression of the luciferase reporter gene. This vector was then used to establish and optimize epimastigote transfection. We then developed highly reproducible conditions that can be used to obtain and select stably transfected mutants that continue metacyclogenesis and are infectious in immunocompetent rodents

Comparing comorbidity measures for predicting mortality and hospitalization in three population-based cohorts

<p>Abstract</p> <p>Background</p> <p>Multiple comorbidity measures have been developed for risk-adjustment in studies using administrative data, but it is unclear which measure is optimal for specific outcomes and if the measures are equally valid in different populations. This research examined the predictive performance of five comorbidity measures in three population-based cohorts.</p> <p>Methods</p> <p>Administrative data from the province of Saskatchewan, Canada, were used to create the cohorts. The general population cohort included all Saskatchewan residents 20+ years, the diabetes cohort included individuals 20+ years with a diabetes diagnosis in hospital and/or physician data, and the osteoporosis cohort included individuals 50+ years with diagnosed or treated osteoporosis. Five comorbidity measures based on health services utilization, number of different diagnoses, and prescription drugs over one year were defined. Predictive performance was assessed for death and hospitalization outcomes using measures of discrimination (<it>c</it>-statistic) and calibration (Brier score) for multiple logistic regression models.</p> <p>Results</p> <p>The comorbidity measures with optimal performance were the same in the general population (<it>n </it>= 662,423), diabetes (<it>n </it>= 41,925), and osteoporosis (<it>n </it>= 28,068) cohorts. For mortality, the Elixhauser index resulted in the highest <it>c</it>-statistic and lowest Brier score, followed by the Charlson index. For hospitalization, the number of diagnoses had the best predictive performance. Consistent results were obtained when we restricted attention to the population 65+ years in each cohort.</p> <p>Conclusions</p> <p>The optimal comorbidity measure depends on the health outcome and not on the disease characteristics of the study population.</p