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881.
Long-term studies of invasive populations are rare, which is unfortunate because important aspects of their dynamics may only be detected over long term. For instance, invasive populations can experience substantial population declines, or even crashes, sometime after their introduction and invasion. Potamopyrgus antipodarum (Caenogastropoda) is a successful invader, and is rarely parasitized in introduced areas. In France, the snail is parasitized as first intermediate host by only one trematode species (Aporocotylid sp. I), native to the snail’s home range, New Zealand. Here, we examined the dynamics of the molluscan assemblage in a French stream on a 14-year interval (2000–2004 and 2009–2013), focusing on this introduced host-parasite association. Overall, P. antipodarum was numerically dominant (90.80%) among molluscs, also including sphaeriid clams (9.12%) and pulmonate snails (0.08%). However, during the last monitoring period, we found a substantial population decline of P. antipodarum, potentially driven by environmental change, such as decreased water temperature and depth, and possibly competitive interactions with sphaeriids, which became numerically dominant (56.34%). P. antipodarum was the only mollusc found infected and only by Aporocotylid sp. I. Interestingly, despite low monthly prevalence (from 0 to 1.52%) and snail host population decline, the P. antipodarum-aporocotylid relationship appeared to be persistent over time. 相似文献
882.
Maxime Delos François Foulquier Charles Hellec Dorothée Vicogne Alexandre Fifre Mathieu Carpentier Dulce Papy-Garcia Fabrice Allain Agnès Denys 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(7):1644-1655
Background
Heparan sulfate (HS) 3-O-sulfation can be catalysed by seven 3-O-sulfotransferases (HS3STs) in humans, still it is the rarest modification in HS and its biological function is yet misunderstood. HS3ST2 and HS3ST3B exhibit the same activity in vitro. They are however differently expressed in macrophages depending on cell environment, which suggests that they may be involved in distinct cellular processes. Here, we hypothesized that both isozymes might also display distinct subcellular localizations.Methods
The subcellular distribution of HS3ST2 and HS3ST3B was analysed by using overexpression systems in HeLa cells. The localization of endogenous HS3ST2 was confirmed by immunostaining in primary macrophages.Results
We found that HS3ST3B was only localized in the Golgi apparatus and no difference between full-length enzyme and truncated construct depleted of its catalytic domain was observed. In contrast, HS3ST2 was clearly visualized at the plasma membrane. Its truncated form remained in the Golgi apparatus, meaning that the catalytic domain might support correct addressing of HS3ST2 to cell surface. Moreover, we found a partial co-localization of HS3ST2 with syndecan-2 in HeLa cells and primary macrophages. Silencing the expression of this proteoglycan altered the localization of HS3ST2, which suggests that syndecan-2 is required to address the isozyme outside of the Golgi apparatus.Conclusions
We demonstrated that HS3ST3B is a Golgi-resident isozyme, while HS3ST2 is addressed to the plasma membrane with syndecan-2.General significance
The membrane localization of HS3ST2 suggests that this enzyme may participate in discrete processes that occur at the cell surface. 相似文献883.
Katrien Van Petegem Felix Moerman Maxime Dahirel Emanuel A. Fronhofer Martijn L. Vandegehuchte Thomas Van Leeuwen Nicky Wybouw Robby Stoks Dries Bonte 《Ecology letters》2018,21(2):225-234
With ongoing global change, life is continuously forced to move to novel areas, which leads to dynamically changing species ranges. As dispersal is central to range dynamics, factors promoting fast and distant dispersal are key to understanding and predicting species ranges. During range expansions, genetic variation is depleted at the expanding front. Such conditions should reduce evolutionary potential, while increasing kin competition. Organisms able to recognise relatives may be able to assess increased levels of relatedness at expanding range margins and to increase their dispersal in a plastic manner. Using individual‐based simulations and experimental range expansions of a spider mite, we demonstrate that plastic responses to kin structure can be at least as important as evolution in driving range expansion speed. Because recognition of kin or kind is increasingly documented across the tree of life, we anticipate it to be a highly important but neglected driver of range expansions. 相似文献
884.
885.
Oriane?Bourgeon Clémence?PagnouxEmail author Stéphane?Mauné Enrique?García?Vargas Sarah?Ivorra Vincent?Bonhomme Mohammed?Ater Abdelmajid?Moukhli Jean-Frédéric?Terral 《Vegetation History and Archaeobotany》2018,27(3):463-476
During the excavations of a Roman amphora workshop and oil mill of the 1st–4th century ad in Las Delicias, Genil valley, Ecija, Spain, large quantities of charred olive stones were recovered. The assemblages discovered in the pottery kilns demonstrate the use as fuel of olive residues, which were obtained from the extraction of the oil in the nearby mill. The abundance of material offered the opportunity to study the infra-specific diversity of the olives growing in the province of Baetica, which is known to have been an important oil-producing region during the Roman Empire. In total, 335 intact charred archaeological olive stones were analysed using geometric morphometry (outline analysis) and compared with several current morphotypes. These have been identified within a set of dimensional references of the stones established from the morphometric study of current varieties and wild populations, including genuinely wild and feral forms of olives, from various areas around the Mediterranean. The morphotype mainly found in wild populations was widely represented among the olive stones from Las Delicias. A large proportion of the archaeological stones were however close to various domesticated forms, which reflect the history of the region and of its varied cultural Mediterranean influences, Punic, Greek and Roman. Moreover, intermediate forms between two distinct morphotypes were identified. They suggest that hybrid olive trees derived from crosses among domesticated varieties and also between domesticated and wild forms, were grown in Las Delicias. In the Genil valley, Roman olive cultivation was based on a set of local olives which included wild and domesticated varieties from various origins, and whose diversity arose from breeding for improvement of varieties. 相似文献
886.
Maxime W.C. Rousseaux Tyler Tschumperlin Hsiang-Chih Lu Elizabeth P. Lackey Vitaliy V. Bondar Ying-Wooi Wan Qiumin Tan Carolyn J. Adamski Jillian Friedrich Kirk Twaroski Weili Chen Jakub Tolar Christine Henzler Ajay Sharma Aleksandar Bajić Tao Lin Lisa Duvick Zhandong Liu Harry T. Orr 《Neuron》2018,97(6):1235-1243.e5
887.
Megan K. Fuller Denver M. Faulk Nambirajan Sundaram Maxime M. Mahe Kara M. Stout Richard J. von Furstenberg Brian J. Smith Kirk K. McNaughton Noah F. Shroyer Michael A. Helmrath Susan J. Henning 《Cell and tissue research》2013,354(2):441-450
Intestinal stem cells (ISCs) are responsible for renewal of the epithelium both during normal homeostasis and following injury. As such, they have significant therapeutic potential. However, whether ISCs can survive tissue storage is unknown. We hypothesize that, although the majority of epithelial cells might die, ISCs would remain viable for at least 24 h at 4 °C. To explore this hypothesis, jejuna of C57Bl6/J or Lgr5-LacZ mice were removed and either processed immediately or placed in phosphate-buffered saline at 4 °C. Delayed isolation of epithelium was performed after 24, 30, or 48 h storage. At the light microscope level, despite extensive apoptosis of villus epithelial cells, small intestinal crypts remained morphologically intact for 30 h and ISCs were identifiable via Lgr5-LacZ positivity. Electron microscopy showed that ISCs retained high integrity for 24 h. When assessed by flow cytometry, ISCs were more resistant to degeneration than the rest of the epithelium, including neighboring Paneth cells, with higher viability across all time points. Cultured isolated crypts showed no loss of capacity to form complex enteroids after 24 h tissue storage, with efficiencies after 7 days of culture remaining above 80 %. By 30 h storage, efficiencies declined but budding capability was retained. We conclude that, with delay in isolation, ISCs remain viable and retain their proliferative capacity. In contrast, the remainder of the epithelium, including the Paneth cells, exhibits degeneration and programmed cell death. If these findings are recapitulated in human tissue, storage at 4 °C might offer a valuable temporal window for the harvesting of crypts or ISCs for therapeutic application. 相似文献
888.
Emily Ayoub Anita Hall Adam M. Scott Mélanie J. Chagnon Géraldine Miquel Maxime Hallé Masaharu Noda Andreas Bikfalvi Michel L. Tremblay 《The Journal of biological chemistry》2013,288(36):25739-25748
PTP-PEST is a cytosolic ubiquitous protein tyrosine phosphatase (PTP) that contains, in addition to its catalytic domain, several protein-protein interaction domains that allow it to interface with several signaling pathways. Among others, PTP-PEST is a key regulator of cellular motility and cytoskeleton dynamics. The complexity of the PTP-PEST interactome underscores the necessity to identify its interacting partners and physiological substrates in order to further understand its role in focal adhesion complex turnover and actin organization. Using a modified yeast substrate trapping two-hybrid system, we identified a cytosolic adaptor protein named Src kinase-associated phosphoprotein 55 homologue (SKAP-Hom) as a novel substrate of PTP-PEST. To confirm PTP-PEST interaction with SKAP-Hom, in vitro pull down assays were performed demonstrating that the PTP catalytic domain and Proline-rich 1 (P1) domain are respectively binding to the SKAP-Hom Y260 and Y297 residues and its SH3 domain. Subsequently, we generated and rescued SKAP-Hom-deficient mouse embryonic fibroblasts (MEFs) with WT SKAP-Hom, SKAP-Hom tyrosine mutants (Y260F, Y260F/Y297F), or SKAP-Hom SH3 domain mutant (W335K). Given the role of PTP-PEST, wound-healing and trans-well migration assays were performed using the generated lines. Indeed, SKAP-Hom-deficient MEFs showed a defect in migration compared with WT-rescued MEFs. Interestingly, the SH3 domain mutant-rescued MEFs showed an enhanced cell migration corresponding potentially with higher tyrosine phosphorylation levels of SKAP-Hom. These findings suggest a novel role of SKAP-Hom and its phosphorylation in the regulation of cellular motility. Moreover, these results open new avenues by which PTP-PEST regulates cellular migration, a hallmark of metastasis. 相似文献
889.
The brown ear tick Rhipicephalus appendiculatus, vector of East Coast fever (ECF) and related cattle diseases caused by Theileria parva has never been reported from the Horn of Africa. Habitat suitability for this tick species was predicted using Maxent modelling technique based on R. appendiculatus records in Sub-Saharan Africa. Two models were developed: the first is based on the tropical R. appendiculatus distribution and the one is based on the distribution records in the temperate region of Sub-Saharan Africa. The tropical model shows favourable habitat in much of the Ethiopian highlands. The whole Djibouti, the south eastern Ethiopian lowlands, majority of Somalia and Eritrea were found to be not suitable for the survival and development of this tick species. Highly suitable areas occur in areas which have moderate temperature and high precipitation. Introductions of R. appendiculatus into the Horn of Africa probably have been prevented by the natural barrier between the known R. appendiculatus distribution range in East Africa and the Horn of Africa. The effect of an introduction of R. appendiculatus and thereby ECF into the Horn of Africa could be catastrophic since the cattle in this area have no immunity against ECF, and mortality might be considerable in all age groups of cattle. 相似文献
890.
Pollen grains have long fascinated biologists who used their remarkable interspecific diversity as a marker to infer profiles of past and present vegetations and environment. This study addresses the question of the diversity of the morphology of pollen grains at the intraspecific level: how different are pollen grains of the same species sampled in different populations? Such differences are expected, and are actually well known to palynologists, but at the same time technically challenging to quantify. We used elliptic Fourier analysis, a powerful morphometric approach for the comparison of outlines, on equatorial and polar views of 30 pollen grains sampled in two different populations for each of five tropical species, thus yielding 600 outlines. Multivariate analysis of variance revealed intraspecific variation of shape of the pollen grains in three out of the five species studied. Our goal here was to test if there were differences in the shape of pollen. This, to our knowledge, would be the first such study of this particular aspect of palynology. We also discuss some relevant evolutionary hypotheses. Further studies using outline analysis, coupled with a choice of appropriate sampling strategies, to suit varying environmental conditions, would prove of great value in testing such hypotheses. 相似文献