609 research outputs found

    Specificity Between Lactobacilli And Hymenopteran Hosts Is The Exception Rather Than The Rule

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    Lactobacilli (Lactobacillales: Lactobacillaceae) are well known for their roles in food fermentation, as probiotics, and in human health, but they can also be dominant members of the microbiota of some species of Hymenoptera (ants, bees, and wasps). Honey bees and bumble bees associate with host-specific lactobacilli, and some evidence suggests that these lactobacilli are important for bee health. Social transmission helps maintain associations between these bees and their respective microbiota. To determine whether lactobacilli associated with social hymenopteran hosts are generally host specific, we gathered publicly available Lactobacillus 16S rRNA gene sequences, along with Lactobacillus sequences from 454 pyrosequencing surveys of six other hymenopteran species (three sweat bees and three ants). We determined the comparative secondary structural models of 16S rRNA, which allowed us to accurately align the entire 16S rRNA gene, including fast-evolving regions. BLAST searches and maximum-likelihood phylogenetic reconstructions confirmed that honey and bumble bees have host-specific Lactobacillus associates. Regardless of colony size or within-colony oral sharing of food (trophallaxis), sweat bees and ants associate with lactobacilli that are closely related to those found in vertebrate hosts or in diverse environments. Why honey and bumble bees associate with host-specific lactobacilli while other social Hymenoptera do not remains an open question. Lactobacilli are known to inhibit the growth of other microbes and can be beneficial whether they are coevolved with their host or are recruited by the host from environmental sources through mechanisms of partner choice.National Science Foundation PRFB-1003133, DEB-0919519Texas Higher Education Coordinating Board 01923, National Institutes of Health GM067317Integrative BiologyCellular and Molecular BiologyCenter for Computational Biology and BioinformaticsBrackenridge Field Laborator

    ACCELERATING CLIMATE CHANGE IMPACTS ON ALPINE GLACIER FOREFIELD ECOSYSTEMS IN THE EUROPEAN ALPS

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    In the European Alps the increase in air temperature was more than twice the increase in global mean temperature over the last 50 years. The abiotic ( glacial) and the biotic components ( plants and vegetation) of the mountain environment are showing ample evidence of climate change impacts. In the Alps most small glaciers (80% of total glacial coverage and an important contribution to water resources) could disappear in the next decades. Recently climate change was demonstrated to affect higher levels of ecological systems, with vegetation exhibiting surface area changes, indicating that alpine and nival vegetation may be able to respond in a fast and flexible way in response to 1-2 degrees C warming. We analyzed the glacier evolution ( terminus fluctuations, mass balances, surface area variations), local climate, and vegetation succession on the forefield of Sforzellina Glacier ( Upper Valtellina, central Italian Alps) over the past three decades. We aimed to quantify the impacts of climate change on coupled biotic and abiotic components of high alpine ecosystems, to verify if an acceleration was occurring on them during the last decade (i.e., 1996-2006) and to assess whether new specific strategies were adopted for plant colonization and development. All the glaciological data indicate that a glacial retreat and shrinkage occurred and was much stronger after 2002 than during the last 35 years. Vegetation started to colonize surfaces deglaciated for only one year, with a rate at least four times greater than that reported in the literature for the establishment of scattered individuals and about two times greater for the well-established discontinuous early-successional community. The colonization strategy changed: the first colonizers are early-successional, scree slopes, and perennial clonal species with high phenotypic plasticity rather than pioneer and snowbed species. This impressive acceleration coincided with only slight local summer warming ( approximately +0.5 degrees C) and a poorly documented local decrease in the snow cover depth and duration. Are we facing accelerated ecological responses to climatic changes and/or did we go beyond a threshold over which major ecosystem changes may occur in response to even minor climatic variations?

    Ichthyophonus irregularis sp. nov. from the yellowtail flounder Limanda ferruginea from the Nova Scotia shelf

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    A previously described unusual form of the protistan parasite Ichthyophonus, differing in morphological and developmental features from I. hoferi sensu Plehn & Mulsow, was recovered from yellowtail flounder Limanda ferruginea Storer from the Brown's Bank area of the Nova Scotia shelf. The nuclear gene encoding the rRNA of the small ribosomal subunit was amplified from this unusual form of Ichthyophonus using the polymerase chain reaction, sequenced and aligned with other eukaryote small subunit (ssu)-rDNAs. Inferred phylogenetic trees clearly show that its ssu-rDNA is distinct from those of 2 isolates of I. hoferi sensu Plehn & Mulsow from different hosts and geographical locations (herring in the North Sea, and yellowtail flounder from the Nova Scotia shelf). We consider the unusual form to be a separate species, I. irregularis. The occurrence of a second, distinct type of Ichthyophonus within a single host species raises the possibility that ichthyophoniasis could be produced by different (although related) pathogens, and in some cases, by concurrent infections of the two

    Comparison of endometrial polyp recurrence in fertile women after office hysteroscopic endometrial polypectomy using two widely spread techniques

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    Aim: To compare the recurrence of benign endometrial polyps after office hysteroscopic polypectomy performed with a bipolar electrode (BE) or a small diameter hysteroscopic tissue removal system (HTRs). Methods: From July 2018 to December 2019 we evaluated the charts of 114 asymptomatic fertile women who underwent office hysteroscopic polypectomy, 1 year before, for a single large benign endometrial polyp (size between 10 and 20 mm) using a 4 mm continuous flow hysteroscope with a BE or a 5 mm HTRs. Patients, divided into two groups according to surgical procedure, each performed exclusively by one expert gynecologist, were scheduled for a 12-month postoperative transvaginal sonography to evaluate the recurrence of endometrial polyps. Results: Forty-eight women of the BE group and 42 of the HTRs group were considered for the 1-year transvaginal sonography follow-up. Five polyps were identified in the BE group and three in the HTRs group (5/48 vs 3/42, P = n.s.). All polyps were removed hysteroscopically (in three out of five and in two out of three cases, respectively, in the same places of the previous polypectomy) and evaluated as ‘benign’ by the pathologist. Conclusion: Office hysteroscopic endometrial polypectomy with small HTRs compared to BE revealed at a 1-year follow-up no difference in terms of complete removal and recurrence of polyps. HTRs polypectomy resulted in less pain and significantly quicker time of procedure compared to BE. This data should be kept in mind for patient comfort any time hysteroscopic polypectomy is planned in an office setting

    Randomised trial comparing biweekly oxaliplatin plus oral capecitabine versus oxaliplatin plus i.v. bolus fluorouracil/leucovorin in metastatic colorectal cancer patients: results of the Southern Italy Cooperative Oncology study 0401

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    Oxaliplatin combined with either fluorouracil/leucovorin (OXAFAFU) or capecitabine (OXXEL) has a demonstrated activity in metastatic colorectal cancer patients. We aimed at comparing these two regimens in terms of response rate (RR), safety, progression-free survival (PFS), and quality of life (QoL) of patients

    Ethnic fragmentation and degree of urbanization strongly affect the discrimination power of Y-STR haplotypes in central Sahel

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    Y chromosome short tandem repeats (Y-STRs) are commonly used to identify male lineages for investigative and judicial purposes and could represent the only source of male-specific genetic information from unbalanced female-male mixtures. The Yfiler Plus multiplex, which includes twenty conventional and seven rapidly-mutating Y-STRs, represents the most discriminating patrilineal system commercially available to date. Over the past five years, this multiplex has been used to analyze several Eurasian populations, with a reported discrimination capacity (DC) approaching or corresponding to the highest possible value. However, despite the inclusion of rapidly mutating Y-STRs, extensive haplotype sharing was still reported for some African populations due to a number of different factors affecting the effective population size. In the present study, we analyzed 27 Y-STRs included in the Yfiler Plus multiplex and 82 Y-SNPs in central Sahel (northern Cameroon and western Chad), an African region characterized by a strong ethnic fragmentation and linguistic diversity. We evaluated the effects of population sub-structuring on genetic diversity by stratifying a sample composed of 431 males according to their ethnicity (44 different ethnic groups) and urbanization degree (four villages and four towns). Overall, we observed a low discrimination capacity (DC = 0.90), with 71 subjects (16.5 %) sharing 27 Y-STR haplotypes. Haplotype sharing was essentially limited to subjects with the same binary haplogroup, coming from the same location and belonging to the same ethnic group. Haplotype sharing was much higher in rural areas (average DC = 0.83) than urban settlements (average DC = 0.96) with a significant correlation between DC and census size (r = 0.89; p = 0.003). Notably, we found that genetic differentiation between villages from the same country (ΦST = 0.14) largely exceeded that found among countries (ΦST = 0.02). These findings have important implications for the choice of the appropriate reference population database to evaluate the statistical relevance of forensic Y-haplotype matches

    Viscous-Inviscid Interactions in a Boundary-Layer Flow Induced by a Vortex Array

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    In this paper we investigate the asymptotic validity of boundary layer theory. For a flow induced by a periodic row of point-vortices, we compare Prandtl's solution to Navier-Stokes solutions at different ReRe numbers. We show how Prandtl's solution develops a finite time separation singularity. On the other hand Navier-Stokes solution is characterized by the presence of two kinds of viscous-inviscid interactions between the boundary layer and the outer flow. These interactions can be detected by the analysis of the enstrophy and of the pressure gradient on the wall. Moreover we apply the complex singularity tracking method to Prandtl and Navier-Stokes solutions and analyze the previous interactions from a different perspective

    Recommendation of RILEM TC237-SIB on cohesion test of recycled asphalt

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    This recommendation describes how to evaluate the presence of potentially active bitumen in recycled asphalt (RA) materials through the cohesion test. The experimental protocol is designed according to the research performed by the RILEM Technical Committee 237-SIB ‘‘Testing and characterization of sustainable innovative bituminous materials and systems’’ with the purpose, to develop a new, simple and fast method for the characterization of RA while limiting the need for conventional rheological tests. The guidelines in this recommendation focus on the testing procedure including specimen preparation, data analysis and provide information on the preparation of a tests report
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