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https://www.readbyqxmd.com/read/27925615/positive-selection-in-cathelicidin-host-defense-peptides-adaptation-to-exogenous-pathogens-or-endogenous-receptors
#1
S Zhu, B Gao
The cause of adaptive protein evolution includes internal (for example, co-evolution of ligand-receptor pairs) and external (for example, adaptation to different ecological niches) mechanisms. Host defense peptides (HDPs) are a class of vertebrate-specific cationic antimicrobial peptides evolving under positive selection. Besides their antibiotic activity, HDPs also exert an effect on multiple host immune cells, thus providing an ideal model to study selective agents driving their evolution. On the basis of a combination of computational and experimental approaches, we studied the evolution of LL-37-type HDPs in mammals, the mature peptide of cathelicidin CAP18 (herein termed CAP18-MP) and investigated the driving force behind the evolution...
December 7, 2016: Heredity
https://www.readbyqxmd.com/read/27920145/three-small-receptive-field-ganglion-cells-in-the-mouse-retina-are-distinctly-tuned-to-size-speed-and-object-motion
#2
Jason Jacoby, Gregory W Schwartz
: Retinal ganglion cells (RGCs) are frequently divided into functional types by their ability to extract and relay specific features from a visual scene, such as the capacity to discern local or global motion, direction of motion, stimulus orientation, contrast or uniformity, or the presence of large or small objects. Here we introduce three previously uncharacterized, non-direction selective ON-OFF RGC types that represent a distinct set of feature detectors in the mouse retina. The three high definition (HD) RGCs possess small receptive field (RF) centers and strong surround suppression...
December 5, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27919445/effective-production-of-recipient-male-pigs-for-spermatogonial-stem-cell-transplantation-by-intratesticular-injection-with-busulfan
#3
Zhuoheng Lin, Jiajing Bao, Qunfang Kong, Yaofu Bai, Fenhua Luo, Zhou Songyang, Yingji Wu, Junjiu Huang
Germ cell transplantation has facilitated spermatogonial stem cell (SSC) and spermatogenesis research and shown great potential in the seed-breeding of domestic livestock. However, little progress has been made in large animals, primarily reflecting the difficulties in preparing sterile recipients. Here, we developed a novel protocol to prepare recipient pigs through the direct injection of busulfan into the cavum vaginale of the scrotums of Landrace-Large bi-crossbreeding male pigs and Seghers male pigs, two economically-important types of pigs, to eliminate endogenous spermatogonia...
November 1, 2016: Theriogenology
https://www.readbyqxmd.com/read/27911997/community-trait-structure-in-phytoplankton-seasonal-dynamics-from-a-method-for-sparse-trait-data
#4
Kyle F Edwards
The distribution of functional traits in communities, and how trait distributions shift over time and space, is critical information for understanding community structure, the maintenance of diversity, and community effects on ecosystem function. It is often the case that traits tightly linked to ecological performance, such as physiological capacities, are laborious to measure and largely unknown for speciose communities; however, these traits are particularly important for unraveling the mechanistic basis of community structure...
December 2016: Ecology
https://www.readbyqxmd.com/read/27911919/few-ant-species-play-a-central-role-linking-different-plant-resources-in-a-network-in-rupestrian-grasslands
#5
Fernanda V Costa, Marco A R Mello, Judith L Bronstein, Tadeu J Guerra, Renata L Muylaert, Alice C Leite, Frederico S Neves
Ant-plant associations are an outstanding model to study the entangled ecological interactions that structure communities. However, most studies of plant-animal networks focus on only one type of resource that mediates these interactions (e.g, nectar or fruits), leading to a biased understanding of community structure. New approaches, however, have made possible to study several interaction types simultaneously through multilayer networks models. Here, we use this approach to ask whether the structural patterns described to date for ant-plant networks hold when multiple interactions with plant-derived food rewards are considered...
2016: PloS One
https://www.readbyqxmd.com/read/27911438/evolutionary-convergence-in-experimental-pseudomonas-populations
#6
Peter A Lind, Andrew D Farr, Paul B Rainey
Model microbial systems provide opportunity to understand the genetic bases of ecological traits, their evolution, regulation and fitness contributions. Experimental populations of Pseudomonas fluorescens rapidly diverge in spatially structured microcosms producing a range of surface-colonising forms. Despite divergent molecular routes, wrinkly spreader (WS) niche specialist types overproduce a cellulosic polymer allowing mat formation at the air-liquid interface and access to oxygen. Given the range of ways by which cells can form mats, such phenotypic parallelism is unexpected...
December 2, 2016: ISME Journal
https://www.readbyqxmd.com/read/27908803/pericytes-integral-components-of-adult-hematopoietic-stem-cell-niches
#7
REVIEW
D Sá da Bandeira, J Casamitjana, M Crisan
The interest in perivascular cells as a niche for adult hematopoietic stem cells (HSCs) is significantly growing. In the adult bone marrow (BM), perivascular cells and HSCs cohabit. Among perivascular cells, pericytes are precursors of mesenchymal stem/stromal cells (MSCs) that are capable of differentiating into osteoblasts, adipocytes and chondrocytes. In situ, pericytes are recognised by their localisation to the abluminal side of the blood vessel wall, closely associated with endothelial cells in combination with the expression of markers such as CD146, neural glial 2 (NG2), platelet derived growth factor receptor β (PDGFRβ), α-smooth muscle actin (α-SMA), nestin (Nes) and/or leptin receptor (LepR)...
November 28, 2016: Pharmacology & Therapeutics
https://www.readbyqxmd.com/read/27908291/muscle-pgc-1%C3%AE-modulates-satellite-cell-number-and-proliferation-by-remodeling-the-stem-cell-niche
#8
Ivana Dinulovic, Regula Furrer, Markus Beer, Arnaud Ferry, Bettina Cardel, Christoph Handschin
BACKGROUND: The myogenic capacity of satellite cells (SCs), adult muscle stem cells, is influenced by aging, exercise, and other factors. In skeletal muscle, the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a key regulator of oxidative metabolism and endurance training adaptation. However, a link between PGC-1α and SC behavior remains unexplored. METHODS: We have now studied SC function in a PGC-1α fiber-specific gain-of-function animal model...
December 2, 2016: Skeletal Muscle
https://www.readbyqxmd.com/read/27905469/selection-for-predation-not-female-fecundity-explains-sexual-size-dimorphism-in-the-orchid-mantises
#9
Gavin J Svenson, Sydney K Brannoch, Henrique M Rodrigues, James C O'Hanlon, Frank Wieland
Here we reconstruct the evolutionary shift towards floral simulation in orchid mantises and suggest female predatory selection as the likely driving force behind the development of extreme sexual size dimorphism. Through analysis of body size data and phylogenetic modelling of trait evolution, we recovered an ancestral shift towards sexual dimorphisms in both size and appearance in a lineage of flower-associated praying mantises. Sedentary female flower mantises dramatically increased in size prior to a transition from camouflaged, ambush predation to a floral simulation strategy, gaining access to, and visually attracting, a novel resource: large pollinating insects...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27903256/revealing-hidden-species-diversity-in-closely-related-species-using-nuclear-snps-ssrs-and-dna-sequences-a-case-study-in-the-tree-genus-milicia
#10
Kasso Daïnou, Céline Blanc-Jolivet, Bernd Degen, Priscilla Kimani, Dyana Ndiade-Bourobou, Armel S L Donkpegan, Félicien Tosso, Esra Kaymak, Nils Bourland, Jean-Louis Doucet, Olivier J Hardy
BACKGROUND: Species delimitation in closely related plant taxa can be challenging because (i) reproductive barriers are not always congruent with morphological differentiation, (ii) use of plastid sequences might lead to misinterpretation, (iii) rare species might not be sampled. We revisited molecular-based species delimitation in the African genus Milicia, currently divided into M. regia (West Africa) and M. excelsa (from West to East Africa). We used 435 samples collected in West, Central and East Africa...
December 1, 2016: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/27903056/spatial-pattern-evolution-of-aedes-aegypti-breeding-sites-in-an-argentinean-city-without-a-dengue-vector-control-programme
#11
Manuel O Espinosa, Francisco Polop, Camilo H Rotela, Marcelo Abril, Carlos M Scavuzzo
The main objective of this study was to obtain and analyse the space-time dynamics of Aedes aegypti breeding sites in Clorinda City, Formosa Province, Argentina coupled with landscape analysis using the maximum entropy approach in order to generate a dengue vector niche model. In urban areas, without vector control activities, 12 entomologic (larval) samplings were performed during three years (October 2011 to October 2014). The entomologic surveillance area represented 16,511 houses. Predictive models for Aedes distribution were developed using vector breeding abundance data, density analysis, clustering and geoprocessing techniques coupled with Earth observation satellite data...
November 21, 2016: Geospatial Health
https://www.readbyqxmd.com/read/27901089/a-silac-based-method-for-quantitative-proteomic-analysis-of-intestinal-organoids
#12
Alexis Gonneaud, Christine Jones, Naomie Turgeon, Dominique Lévesque, Claude Asselin, François Boudreau, François-Michel Boisvert
Organoids have the potential to bridge 3D cell culture to tissue physiology by providing a model resembling in vivo organs. Long-term growing organoids were first isolated from intestinal crypt cells and recreated the renewing intestinal epithelial niche. Since then, this technical breakthrough was applied to many other organs, including prostate, liver, kidney and pancreas. We describe here how to apply a SILAC-based quantitative proteomic approach to measure protein expression changes in intestinal organoids under different experimental conditions...
November 30, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27899994/targeting-of-the-leukemia-microenvironment-by-c-rgdfv-overcomes-the-resistance-to-chemotherapy-in-acute-myeloid-leukemia-in-biomimetic-polystyrene-scaffolds
#13
Zhao-Hua Shen, Dong-Feng Zeng, Xiao-Yan Wang, Ying-Ying Ma, Xi Zhang, Pei-Yan Kong
The bone marrow microenvironment provides a relative sanctuary from cytotoxic drugs for leukemia cells. The present niche models concentrate on a two-dimensional (2D) co-culture system in vitro, which does not imitate the in vivo environment, while the 3D scaffolds are more reflective of this. Osteopontin (Opn) secreted by bone marrow osteoblasts, may participate in protecting leukemia cells from apoptosis by binding to its receptor αvβ3, which can be expressed on the surface of the leukemia MV4-11 cell line...
November 2016: Oncology Letters
https://www.readbyqxmd.com/read/27898178/pre-rain-green-up-is-ubiquitous-across-southern-tropical-africa-implications-for-temporal-niche-separation-and-model-representation
#14
Casey M Ryan, Mathew Williams, John Grace, Emily Woollen, Caroline E R Lehmann
Tree phenology mediates land-atmosphere mass and energy exchange and is a determinant of ecosystem structure and function. In the dry tropics, including African savannas, many trees grow new leaves during the dry season - weeks or months before the rains typically start. This syndrome of pre-rain green-up has long been recognized at small scales, but the high spatial and interspecific variability in leaf phenology has precluded regional generalizations. We used remote sensing data to show that this precocious phenology is ubiquitous across the woodlands and savannas of southern tropical Africa...
November 29, 2016: New Phytologist
https://www.readbyqxmd.com/read/27895171/impairment-of-ccr6-and-cxcr3-th-cell-migration-in-hiv-1-infection-is-rescued-by-modulating-actin-polymerization
#15
Valentina Cecchinato, Enos Bernasconi, Roberto F Speck, Michele Proietti, Ulrike Sauermann, Gianluca D'Agostino, Gabriela Danelon, Tanja Rezzonico Jost, Fabio Grassi, Lorenzo Raeli, Franziska Schöni-Affolter, Christiane Stahl-Hennig, Mariagrazia Uguccioni
CD4(+) T cell repopulation of the gut is rarely achieved in HIV-1-infected individuals who are receiving clinically effective antiretroviral therapy. Alterations in the integrity of the mucosal barrier have been indicated as a cause for chronic immune activation and disease progression. In this study, we present evidence that persistent immune activation causes impairment of lymphocytes to respond to chemotactic stimuli, thus preventing their trafficking from the blood stream to peripheral organs. CCR6(+) and CXCR3(+) Th cells accumulate in the blood of aviremic HIV-1-infected patients on long-term antiretroviral therapy, and their frequency in the circulation positively correlates to levels of soluble CD14 in plasma, a marker of chronic immune activation...
November 28, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/27893284/biomarkers-and-metabolic-patterns-in-the-sediments-of-evolving-glacial-lakes-as-a-proxy-for-planetary-lake-exploration
#16
Víctor Parro, Yolanda Blanco, Fernando Puente-Sánchez, Luis A Rivas, Mercedes Moreno-Paz, Alex Echeverría, Guillermo Chong-Díaz, Cecilia Demergasso, Nathalie A Cabrol
Oligotrophic glacial lakes in the Andes Mountains serve as models to study the effects of climate change on natural biological systems. The persistent high UV regime and evolution of the lake biota due to deglaciation make Andean lake ecosystems potential analogues in the search for life on other planetary bodies. Our objective was to identify microbial biomarkers and metabolic patterns that represent time points in the evolutionary history of Andean glacial lakes, as these may be used in long-term studies as microscale indicators of climate change processes...
November 28, 2016: Astrobiology
https://www.readbyqxmd.com/read/27893179/ctra-controls-cell-division-and-outer-membrane-composition-of-the-pathogen-brucella-abortus
#17
Nayla Francis, Katy Poncin, Antonella Fioravanti, Victoria Vassen, Kevin Willemart, Thi Anh Phuong Ong, Luca Rappez, Jean-Jacques Letesson, Emanuele G Biondi, Xavier De Bolle
Brucella abortus is a pathogen infecting cattle, able to survive, traffic and proliferate inside host cells. It belongs to the Alphaproteobacteria, a phylogenetic group comprising bacteria with free living, symbiotic and pathogenic lifestyles. An essential regulator of cell cycle progression named CtrA was described in the model bacterium Caulobacter crescentus. This regulator is conserved in many alphaproteobacteria, but the evolution of its regulon remains elusive. Here we identified promoters that are CtrA targets using ChIP-seq and we found that CtrA binds to promoters of genes involved in cell cycle progression, in addition to numerous genes encoding outer membrane components involved in export of membrane proteins and synthesis of lipopolysaccharide...
November 28, 2016: Molecular Microbiology
https://www.readbyqxmd.com/read/27891142/genetic-structure-and-evolutionary-history-of-three-alpine-sclerophyllous-oaks-in-east-himalaya-hengduan-mountains-and-adjacent-regions
#18
Li Feng, Qi-Jian Zheng, Zeng-Qiang Qian, Jia Yang, Yan-Ping Zhang, Zhong-Hu Li, Gui-Fang Zhao
The East Himalaya-Hengduan Mountains (EH-HM) region has a high biodiversity and harbors numerous endemic alpine plants. This is probably the result of combined orographic and climate oscillations occurring since late Tertiary. Here, we determined the genetic structure and evolutionary history of alpine oak species (including Quercus spinosa, Quercus aquifolioides, and Quercus rehderiana) using both cytoplasmic-nuclear markers and ecological niche models (ENMs), and elucidated the impacts of climate oscillations and environmental heterogeneity on their population demography...
2016: Frontiers in Plant Science
https://www.readbyqxmd.com/read/27890929/extended-time-lapse-in-vivo-imaging-of-tibia-bone-marrow-to-visualize-dynamic-hematopoietic-stem-cell-engraftment
#19
S Kim, L Lin, G A J Brown, K Hosaka, E W Scott
Homing, engraftment and proliferation of hematopoietic stem/progenitor cell (HSC/HPCs) are crucial steps required for success of a bone marrow transplant. Observation of these critical events is limited by the opaque nature of bone. Here we demonstrate how individual HSCs engraft in long bones by thinning one side of the tibia for direct and unbiased observation. Intravital imaging enabled detailed visualization of single Sca-1(+), c-Kit(+), Lineage(-) (SKL) cell migration to bone marrow niches and subsequent proliferation to reconstitute hematopoiesis...
November 28, 2016: Leukemia: Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K
https://www.readbyqxmd.com/read/27890729/maturation-of-human-embryonic-stem-cell-derived-cardiomyocytes-hesc-cms-in-3d-collagen-matrix-effects-of-niche-cell-supplementation-and-mechanical-stimulation
#20
W Zhang, C W Kong, M H Tong, W H Chooi, N Huang, R A Li, B P Chan
: Cardiomyocytes derived from human embryonic stem cells (hESC-CMs) are regarded as a promising source for regenerative medicine, drug testing and disease modeling. Nevertheless, cardiomyocytes are immature in terms of their contractile structure, metabolism and electrophysiological properties. Here, we fabricate cardiac muscle strips by encapsulating hESC-CMs in collagen-based biomaterials. Supplementation of niche cells at 3% to the number of hESC-CMs enhance the maturation of the hESC-CMs in 3D tissue matrix...
November 24, 2016: Acta Biomaterialia
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