The exotic invasive plant Vincetoxicum rossicum is a strong competitor even outside its current realized climatic temperature range

Dog-strangling vine (Vincetoxicum rossicum) is an exotic plant originating from Central and Eastern Europe that is becoming increasingly invasive in southern Ontario, Canada. Once established, it successfully displaces local native plant species but mechanisms behind this plant’s high competitive ability are not fully understood. It is unknown whether cooler temperatures will limit the range expansion of V. rossicum, which has demonstrated high tolerance for other environmental variables such as light and soil moisture. Furthermore, if V. rossicum can establish outside its current climatic limit it is unknown whether competition with native species can significantly contribute to reduce fitness and slow down invasion. We conducted an experiment to test the potential of V. rossicum to spread into northern areas of Ontario using a set of growth chambers to simulate southern and northern Ontario climatic temperature regimes. We also tested plant-plant competition by growing V. rossicum in pots with a highly abundant native species, Solidago canadensis, and comparing growth responses to plants grown alone. We found that the fitness of V. rossicum was not affected by the cooler climate despite a delay in reproductive phenology. Growing V. rossicum with S. canadensis caused a significant reduction in seedpod biomass of V. rossicum. However, we did not detect a temperature x competition interaction in spite of evidence for adaptation of S. canadensis to cooler temperature conditions. We conclude that the spread of V. rossicum north within the tested range is unlikely to be limited by climatic temperature but competition with an abundant native species may contribute to slow it down

Well-managed grazing systems: A forgotten hero of conservation

Ecologically sound grazing management is an underused and underappreciated conservation tool in the eastern United States. We contend that significant policy and educational barriers stand in the way of expanding the use of this conservation tool. Well-managed pasture systems combine vigorous perennial vegetation cover, reduced pesticide and fertilizer inputs, and lower costs of production using ecological approaches to generate ecosystem services for society, as well as economic sustainability for the producer. The majority of currently available conservation policy tools were designed to address either rangeland grazing situations in the western United States or conservation cropping in the eastern United States. To promote well-managed pastures in the eastern United States, resource managers and government agencies struggle to adapt programs that are really designed for annual row crop systems. Additional educational and technical assistance resources are needed for promoting well-managed pasture-based farming in the region. This paper summarizes the potential of well-managed pasture systems to provide ecosystem services, provides thoughts for discussion on the barriers to adoption of such systems in the eastern United States, and offers some solutions to move such systems forward through policy and educational efforts. These ideas were first presented at a symposium as part of the 2011 Annual Conference of the Soil and Water Conservation Society in Washington, DC

Common loss of far-red light photoacclimation in cyanobacteria from hot and cold deserts: a case study in the Chroococcidiopsidales

Deserts represent an extreme challenge for photosynthetic life. Despite their aridity, they are often inhabited by diverse microscopic communities of cyanobacteria. These organisms are commonly found in lithic habitats, where they are partially sheltered from extremes of temperature and UV radiation. However, living under the rock surface imposes additional constraints, such as limited light availability, and enrichment of longer wavelengths than are typically usable for oxygenic photosynthesis. Some cyanobacteria from the genus Chroococcidiopsis can use this light to photosynthesize, in a process known as far-red light photoacclimation, or FaRLiP. This genus has commonly been reported from both hot and cold deserts. However, not all Chroococcidiopsis strains carry FaRLiP genes, thus motivating our study into the interplay between FaRLiP and extreme lithic environments. The abundance of sequence data and strains provided the necessary material for an in-depth phylogenetic study, involving spectroscopy, microscopy, and determination of pigment composition, as well as gene and genome analyses. Pigment analyses revealed the presence of red-shifted chlorophylls d and f in all FaRLiP strains tested. In addition, eight genus-level taxa were defined within the encompassing Chroococcidiopsidales, clarifying the phylogeny of this long-standing polyphyletic order. FaRLiP is near universally present in a generalist genus identified in a wide variety of environments, Chroococcidiopsis sensu stricto, while it is rare or absent in closely related, extremophile taxa, including those preferentially inhabiting deserts. This likely reflects the evolutionary process of gene loss in specialist lineages

Common loss of far-red light photoacclimation in cyanobacteria from hot and cold deserts: a case study in the Chroococcidiopsidales

Deserts represent an extreme challenge for photosynthetic life. Despite their aridity, they are often inhabited by diverse microscopic communities of cyanobacteria. These organisms are commonly found in lithic habitats, where they are partially sheltered from extremes of temperature and UV radiation. However, living under the rock surface imposes additional constraints, such as limited light availability, and enrichment of longer wavelengths than are typically usable for oxygenic photosynthesis. Some cyanobacteria from the genus Chroococcidiopsis can use this light to photosynthesize, in a process known as far-red light photoacclimation, or FaRLiP. This genus has commonly been reported from both hot and cold deserts. However, not all Chroococcidiopsis strains carry FaRLiP genes, thus motivating our study into the interplay between FaRLiP and extreme lithic environments. The abundance of sequence data and strains provided the necessary material for an in-depth phylogenetic study, involving spectroscopy, microscopy, and determination of pigment composition, as well as gene and genome analyses. Pigment analyses revealed the presence of red-shifted chlorophylls d and f in all FaRLiP strains tested. In addition, eight genus-level taxa were defined within the encompassing Chroococcidiopsidales, clarifying the phylogeny of this long-standing polyphyletic order. FaRLiP is near universally present in a generalist genus identified in a wide variety of environments, Chroococcidiopsis sensu stricto, while it is rare or absent in closely related, extremophile taxa, including those preferentially inhabiting deserts. This likely reflects the evolutionary process of gene loss in specialist lineages

Phage Orf family recombinases:conservation of activities and involvement of the central channel in DNA binding

Genetic and biochemical evidence suggests that λ Orf is a recombination mediator, promoting nucleation of either bacterial RecA or phage Redβ recombinases onto single-stranded DNA (ssDNA) bound by SSB protein. We have identified a diverse family of Orf proteins that includes representatives implicated in DNA base flipping and those fused to an HNH endonuclease domain. To confirm a functional relationship with the Orf family, a distantly-related homolog, YbcN, from Escherichia coli cryptic prophage DLP12 was purified and characterized. As with its λ relative, YbcN showed a preference for binding ssDNA over duplex. Neither Orf nor YbcN displayed a significant preference for duplex DNA containing mismatches or 1-3 nucleotide bulges. YbcN also bound E. coli SSB, although unlike Orf, it failed to associate with an SSB mutant lacking the flexible C-terminal tail involved in coordinating heterologous protein-protein interactions. Residues conserved in the Orf family that flank the central cavity in the λ Orf crystal structure were targeted for mutagenesis to help determine the mode of DNA binding. Several of these mutant proteins showed significant defects in DNA binding consistent with the central aperture being important for substrate recognition. The widespread conservation of Orf-like proteins highlights the importance of targeting SSB coated ssDNA during lambdoid phage recombination

Respuesta de la presión arterial post-ejercicio y sus factores asociados

Introdução: Na Academia da Cidade os hipertensos realizam exercício físico diariamente, mas pouco trabalhos tratam sobre o comportamento da pressão arterial (PA) nesses espaços. Outra lacuna refere-se aos fatores preditores da resposta pressórica. Objetivo: investigar o comportamento da pressão arterial e analisar os fatores preditores durante o exercício físico. Métodos: estudo observacional, realizado de dezembro de 2018, janeiro e fevereiro de 2019. Dezesseis hipertensos (58.8±15.3 anos), praticantes de exercício em Academia da Cidade. A PA e frequência cardíaca foram verificadas antes e depois de cada sessão de exercício. A variabilidade da frequência cardíaca foi avaliada em dezembro. Para análise foram usados ANOVA de uma via e regressão linear. Resultados: PA sistólica (PAS) de repouso não reduziu entre os meses de observação. PA diastólica (PAD) de repouso reduziu entre dezembro e janeiro (79.3±9.7mmHg para 73.0±7.1mmHg, p=0.02, D de Cohen=0.77). Em dezembro, para a PAS pós-treinamento, o SDNN (β: 1.6, 95%IC: 0.3 - 0.6, p=0.0), RMSSD (β: -2.0, 95%IC: -2.3 - -1.5, p=0.0) e PAS pré-exercício (β: 0.6, 95%IC:0.3 – 0.8, p= 0.0) foram preditoras. Para a PAD pós-exercício, o LF/HF (β: -0.9, 95%IC: -4.2 - -0.8, p=0.0) e a PAD pré-exercício (β: 0.8, 95%IC: 0.4 – 1.4, p=0.0) foram preditoras. Demais relações foram observadas entre janeiro e fevereiro. Conclusão: apenas a PAD reduziu significantemente. Variáveis do sistema nervoso autônomo, pressão arterial sistólica ou diastólica pré-exercício e frequência cardíaca durante o treino predizem o comportamento da pressão arterial pós-exercício.Introduction: in Academia da Cidade, hypertensive individuals involved in daily exercise practice, but fewer studies have been developed about blood pressure (BP) behavior in these spaces. Another gap refers to the predictive factors for the blood pressure response. Aim: to investigate the blood pressure behavior and to analyze its predictive factors during exercise. Methods: observational study, carried out between December of 2018, January to February 2019. Sixteen hypertensives (58.8 ± 15.3 years) took part in the exercise practice. BP and heart rate were checked before and after each exercise session. Heart rate variability was assessed in April. Statistical analysis was carried out with One-way ANOVA and linear regression. Results: the systolic BP (SBP) at rest did not decrease between the months of observation. The diastolic BP (DBP) at rest decreased between December and January (79.3±9.7mmHg to 73.0±7.1 mmHg, p=0.02, Cohen's D =0.77). In April, for post-training PAS, SDNN (β:1.6, 95%CI: 0.3-0.6, p=0.0), RMSSD (β:-2.0, 95%CI: -2.3 - -1.5, p=0.0) and pre-exercise SBP (β:0.6, 95%CI:0.3-0.8, p=0.0) were predictors. For the post-exercise DBP, the LF/HF (β:-0.9, 95%CI:-4.2 - -0.8, p=0.0) and the pre-exercise DBP (β:0, 8, 95%CI: 0.4-1.4, p=0.0) were predictors. Other relations were observed between February and March. Conclusion: only the PAD reduced significantly. Variables of the autonomic nervous system, systolic or diastolic pre-exercise blood pressure and heart rate during exercise practice predicted the behavior of post-exercise blood pressure.Introducción: En el gimnasio Academia da Cidade las personas hipertensas realizan ejercicio físico a diario. Sin embargo hay pocos trabajos que aborden el comportamiento de la presión arterial (PA) en estos lugares. Otra laguna está vinculada a los factores predictores de la respuesta presórica. Objetivo: investigar el comportamiento de la presión arterial y analizar los factores predictores durante el ejercicio físico. Métodos: estudio observacional realizado durante los meses de diciembre de 2018, enero y febrero de 2019. Dieciséis hipertensos (58.8±15.3 años), que practican ejercicios físicos en el gimnasio Academia da Cidade. Se constató la PA y la frecuencia cardíaca antes y después de cada sesión de ejercicios. La variabilidad de la frecuencia cardíaca se evaluó en diciembre. Para efectuar el análisis se utilizó ANOVA de una vía y regresión linear. Resultados: La PA sistólica (PAS) de reposo no se redujo entre los meses de observación. La PA diastólica (PAD) de reposo se redujo entre diciembre y enero (de 79.3±9.7mmHg a 73.0±7.1mmHg, p=0.02, D de Cohen=0.77). En diciembre, la PAS post-entrenamiento, el SDNN (β: 1.6, 95%IC: 0.3 - 0.6, p=0.0), RMSSD (β: -2.0, 95%IC: -2.3 - -1.5, p=0.0) y la PAS pre-ejercício (β: 0.6, 95%IC:0.3 – 0.8, p= 0.0) fueron predictoras. La PAD post-ejercício, el LF/HF (β: -0.9, 95%IC: -4.2 - -0.8, p=0.0) y la PAD pre-ejercício (β: 0.8, 95%IC: 0.4 – 1.4, p=0.0) fueron predictoras. Se observaron otras relaciones entre enero y febrero. Conclusión: solo la PAD se redujo significativamente. Las variables del sistema nervioso autónomo, la presión arterial sistólica o diastólica pre-ejercício y la frecuencia cardíaca durante el entrenamiento predicen el comportaminto de la presión arterial post-ejercicio.Facultad de Humanidades y Ciencias de la Educació

Validation of a HLA-A2 tetramer flow cytometric method, IFNgamma real time RT-PCR, and IFNgamma ELISPOT for detection of immunologic response to gp100 and MelanA/MART-1 in melanoma patients

<p>Abstract</p> <p>Background</p> <p>HLA-A2 tetramer flow cytometry, IFNγ real time RT-PCR and IFNγ ELISPOT assays are commonly used as surrogate immunological endpoints for cancer immunotherapy. While these are often used as research assays to assess patient's immunologic response, assay validation is necessary to ensure reliable and reproducible results and enable more accurate data interpretation. Here we describe a rigorous validation approach for each of these assays prior to their use for clinical sample analysis.</p> <p>Methods</p> <p>Standard operating procedures for each assay were established. HLA-A2 (A*0201) tetramer assay specific for gp100_209(210M)and MART-1_26–35(27L), IFNγ real time RT-PCR and ELISPOT methods were validated using tumor infiltrating lymphocyte cell lines (TIL) isolated from HLA-A2 melanoma patients. TIL cells, specific for gp100 (TIL 1520) or MART-1 (TIL 1143 and TIL1235), were used alone or spiked into cryopreserved HLA-A2 PBMC from healthy subjects. TIL/PBMC were stimulated with peptides (gp100₂₀₉, gp100_pool, MART-1_27–35, or influenza-M1 and negative control peptide HIV) to further assess assay performance characteristics for real time RT-PCR and ELISPOT methods. Validation parameters included specificity, accuracy, precision, linearity of dilution, limit of detection (LOD) and limit of quantification (LOQ). In addition, distribution was established in normal HLA-A2 PBMC samples. Reference ranges for assay controls were established.</p> <p>Results</p> <p>The validation process demonstrated that the HLA-A2 tetramer, IFNγ real time RT-PCR, and IFNγ ELISPOT were highly specific for each antigen, with minimal cross-reactivity between gp100 and MelanA/MART-1. The assays were sensitive; detection could be achieved at as few as 1/4545–1/6667 cells by tetramer analysis, 1/50,000 cells by real time RT-PCR, and 1/10,000–1/20,000 by ELISPOT. The assays met criteria for precision with %CV < 20% (except ELISPOT using high PBMC numbers with %CV < 25%) although flow cytometric assays and cell based functional assays are known to have high assay variability. Most importantly, assays were demonstrated to be effective for their intended use. A positive IFNγ response (by RT-PCR and ELISPOT) to gp100 was demonstrated in PBMC from 3 melanoma patients. Another patient showed a positive MART-1 response measured by all 3 validated methods.</p> <p>Conclusion</p> <p>Our results demonstrated the tetramer flow cytometry assay, IFNγ real-time RT-PCR, and INFγ ELISPOT met validation criteria. Validation approaches provide a guide for others in the field to validate these and other similar assays for assessment of patient T cell response. These methods can be applied not only to cancer vaccines but to other therapeutic proteins as part of immunogenicity and safety analyses.</p

Functional performance of a bi-layered chitosan-nano-hydroxyapatite osteochondral scaffold : a pre-clinical in vitro tribological study

Osteochondral grafts are used for repair of focal osteochondral lesions. Autologous grafts are the gold standard treatment; however, limited graft availability and donor site morbidity restrict use. Therefore, there is a clinical need for different graft sources/materials which replicate natural cartilage function. Chitosan has been proposed for this application. The aim of this study was to assess the biomechanics and biotribology of a bioresorbable chitosan/chitosan-nano-hydroxyapatite osteochondral construct (OCC), implanted in an in vitro porcine knee experimental simulation model. The OCC implanted in different surgical positions (flush, proud and inverted) was compared to predicate grafts in current clinical use and a positive control consisting of a stainless steel graft implanted proud of the cartilage surface. After 3 h (10 800 cycles) wear simulation under a walking gait, subsidence occurred in all OCC samples irrespective of surgical positioning, but with no apparent loss of material and low meniscus wear. Half the predicate grafts exhibited delamination and scratching of the cartilage surfaces. No graft subsidence occurred in the positive controls but wear and deformation of the meniscus were apparent. Implanting a new chitosan-based OCC either optimally (flush), inverted or proud of the cartilage surface resulted in minimal wear, damage and deformation of the meniscus

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology