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861.
Soil – an underestimated biotope The soil is a biotope with high species abundances and richness. It is, furthermore, a location where important ecosystem services are realized. Recent research projects on the origin and development of soil animal communities, on the heterogeneous interactions within the soil nutrient net and the distribution of soil animals show the different ecological traits and adaptabilities of the world beneath our feet. So research contributes to maintain the eco‐resource of soil and its sustainable use. 相似文献
862.
863.
Anna CC Aguiar Ananda C Cunha Isabela Penna Ceravolo Regina A Correia Gon?alves Arildo JB Oliveira Antoniana Ursine Krettli 《Memórias do Instituto Oswaldo Cruz》2015,110(7):906-913
Several species of Aspidosperma plants are used to treat diseases in
the tropics, including Aspidosperma ramiflorum, which acts against
leishmaniasis, an activity that is experimentally confirmed. The species, known as
guatambu-yellow, yellow peroba,
coffee-peroba andmatiambu, grows in the Atlantic
Forest of Brazil in the South to the Southeast regions. Through a guided
biofractionation of A. ramiflorum extracts, the plant activity
against Plasmodium falciparum was evaluated in vitro for toxicity
towards human hepatoma G2 cells, normal monkey kidney cells and nonimmortalised human
monocytes isolated from peripheral blood. Six of the seven extracts tested were
active at low doses (half-maximal drug inhibitory concentration < 3.8 µg/mL); the
aqueous extract was inactive. Overall, the plant extracts and the purified compounds
displayed low toxicity in vitro. A nonsoluble extract fraction and one purified
alkaloid isositsirikine (compound 5) displayed high selectivity indexes (SI) (= 56
and 113, respectively), whereas compounds 2 and 3 were toxic (SI < 10). The
structure, activity and low toxicity of isositsirikine in vitro are described here
for the first time in A. ramiflorum, but only the neutral and
precipitate plant fractions were tested for activity, which caused up to 53%
parasitaemia inhibition of Plasmodium berghei in mice with
blood-induced malaria. This plant species is likely to be useful in the further
development of an antimalarial drug, but its pharmacological evaluation is still
required. 相似文献
864.
Nutrient and plant secondary compound composition and iron‐binding capacity in leaves and green stems of commonly used plant browse (Carolina willow; Salix caroliniana) fed to zoo‐managed browsing herbivores 下载免费PDF全文
S. R. Lavin K. E. Sullivan S. C. Wooley R. Robinson S. Singh K. Stone S. Russell E. V. Valdes 《Zoo biology》2015,34(6):565-575
865.
Katherine McAuliffe Richard Wrangham Luke Glowacki Andrew F. Russell 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2015,370(1683)
Life abounds with examples of conspecifics actively cooperating to a common end, despite conflicts of interest being expected concerning how much each individual should contribute. Mathematical models typically find that such conflict can be resolved by partial-response strategies, leading investors to contribute relatively equitably. Using a case study approach, we show that such model expectations can be contradicted in at least four disparate contexts: (i) bi-parental care; (ii) cooperative breeding; (iii) cooperative hunting; and (iv) human cooperation. We highlight that: (a) marked variation in contributions is commonplace; and (b) individuals can often respond positively rather than negatively to the contributions of others. Existing models have surprisingly limited power in explaining these phenomena. Here, we propose that, although among-individual variation in cooperative contributions will be influenced by differential costs and benefits, there is likely to be a strong genetic or epigenetic component. We then suggest that selection can maintain high investors (key individuals) when their contributions promote support by increasing the benefits and/or reducing the costs for others. Our intentions are to raise awareness in—and provide testable hypotheses of—two of the most poorly understood, yet integral, questions regarding cooperative ventures: why do individuals vary in their contributions and when does cooperation beget cooperation? 相似文献
866.
867.
Serena C. Hedgepeth M. Iveth Garcia Larry E. Wagner II Ana M. Rodriguez Sree V. Chintapalli Russell R. Snyder Gary D. V. Hankins Beric R. Henderson Kirsty M. Brodie David I. Yule Damian B. van Rossum Darren Boehning 《The Journal of biological chemistry》2015,290(11):7304-7313
The inositol 1,4,5-trisphosphate receptor (IP3R) is a ubiquitously expressed endoplasmic reticulum (ER)-resident calcium channel. Calcium release mediated by IP3Rs influences many signaling pathways, including those regulating apoptosis. IP3R activity is regulated by protein-protein interactions, including binding to proto-oncogenes and tumor suppressors to regulate cell death. Here we show that the IP3R binds to the tumor suppressor BRCA1. BRCA1 binding directly sensitizes the IP3R to its ligand, IP3. BRCA1 is recruited to the ER during apoptosis in an IP3R-dependent manner, and, in addition, a pool of BRCA1 protein is constitutively associated with the ER under non-apoptotic conditions. This is likely mediated by a novel lipid binding activity of the first BRCA1 C terminus domain of BRCA1. These findings provide a mechanistic explanation by which BRCA1 can act as a proapoptotic protein. 相似文献
868.
Josh Lawrimore Paula A. Vasquez Michael R. Falvo Russell M. Taylor II Leandra Vicci Elaine Yeh M. Gregory Forest Kerry Bloom 《The Journal of cell biology》2015,210(4):553-564
The centromere is the DNA locus that dictates kinetochore formation and is visibly apparent as heterochromatin that bridges sister kinetochores in metaphase. Sister centromeres are compacted and held together by cohesin, condensin, and topoisomerase-mediated entanglements until all sister chromosomes bi-orient along the spindle apparatus. The establishment of tension between sister chromatids is essential for quenching a checkpoint kinase signal generated from kinetochores lacking microtubule attachment or tension. How the centromere chromatin spring is organized and functions as a tensiometer is largely unexplored. We have discovered that centromere chromatin loops generate an extensional/poleward force sufficient to release nucleosomes proximal to the spindle axis. This study describes how the physical consequences of DNA looping directly underlie the biological mechanism for sister centromere separation and the spring-like properties of the centromere in mitosis. 相似文献
869.
Joanna Stanicka Eileen G. Russell John F. Woolley Thomas G. Cotter 《The Journal of biological chemistry》2015,290(15):9348-9361
Internal tandem duplication of the FMS-like tyrosine kinase (FLT3-ITD) receptor is present in 20% of acute myeloid leukemia (AML) patients and it has been associated with an aggressive AML phenotype. FLT3-ITD expressing cell lines have been shown to generate increased levels of reactive oxygen species (ROS) and DNA double strand breaks (DSBs). However, the molecular basis of how FLT3-ITD-driven ROS leads to the aggressive form of AML is not clearly understood. Our group has previously reported that inhibition of FLT3-ITD signaling results in post-translational down-regulation of p22phox, a small membrane-bound subunit of the NADPH oxidase (NOX) complex. Here we demonstrated that 32D cells, a myeloblast-like cell line transfected with FLT3-ITD, have a higher protein level of p22phox and p22phox-interacting NOX isoforms than 32D cells transfected with the wild type FLT3 receptor (FLT3-WT). The inhibition of NOX proteins, p22phox, and NOX protein knockdowns caused a reduction in ROS, as measured with a hydrogen peroxide (H2O2)-specific dye, peroxy orange 1 (PO1), and nuclear H2O2, as measured with nuclear peroxy emerald 1 (NucPE1). These reductions in the level of H2O2 following the NOX knockdowns were accompanied by a decrease in the number of DNA DSBs. We showed that 32D cells that express FLT3-ITD have a higher level of both oxidized DNA and DNA DSBs than their wild type counterparts. We also observed that NOX4 and p22phox localize to the nuclear membrane in MV4–11 cells expressing FLT3-ITD. Taken together these data indicate that NOX and p22phox mediate the ROS production from FLT3-ITD that signal to the nucleus causing genomic instability. 相似文献
870.