112 research outputs found
Therapeutic activity of two xanthones in a xenograft murine model of human chronic lymphocytic leukemia
<p>Abstract</p> <p>Background</p> <p>We previously reported that allanxanthone C and macluraxanthone, two xanthones purified from <it>Guttiferae </it>trees, display <it>in vitro </it>antiproliferative and proapoptotic activities in leukemic cells from chronic lymphocytic leukemia (CLL) and leukemia B cell lines.</p> <p>Results</p> <p>Here, we investigated the <it>in vivo </it>therapeutic effects of the two xanthones in a xenograft murine model of human CLL, developed by engrafting CD5-transfected chronic leukemia B cells into SCID mice. Treatment of the animals with five daily injections of either allanxanthone C or macluraxanthone resulted in a significant prolongation of their survival as compared to control animals injected with the solvent alone (<it>p </it>= 0.0006 and <it>p </it>= 0.0141, respectively). The same treatment of mice which were not xenografted induced no mortality.</p> <p>Conclusion</p> <p>These data show for the first time the <it>in vivo </it>antileukemic activities of two plant-derived xanthones, and confirm their potential interest for CLL therapy.</p
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Validation and intercomparison of ocean color algorithms for estimating particulate organic carbon in the oceans
Particulate Organic Carbon (POC) plays a vital role in the ocean carbon cycle. Though relatively small compared with other carbon pools, the POC pool is responsible for large fluxes and is linked to many important ocean biogeochemical processes. The satellite ocean-colour signal is influenced by particle composition, size, and concentration and provides a way to observe variability in the POC pool at a range of temporal and spatial scales. To provide accurate estimates of POC concentration from satellite ocean colour data requires algorithms that are well validated, with uncertainties characterised. Here, a number of algorithms to derive POC using different optical variables are applied to merged satellite ocean colour data provided by the Ocean Colour Climate Change Initiative (OC-CCI) and validated against the largest database of in situ POC measurements currently available. The results of this validation exercise indicate satisfactory levels of performance from several algorithms (highest performance was observed from the algorithms of Stramski et al. (2008) and Loisel et al. (2002)) and uncertainties that are within the requirements of the user community. Estimates of the standing stock of the POC can be made by applying these algorithms, and yield an estimated
mixed-layer integrated global stock of POC between 0.77 and 1.3 Pg C of carbon. Performance of the algorithms vary regionally, suggesting that blending of region-specific algorithms may provide the best way forward for generating global POC products
Reduction of radiation dose by application of optimized filtered backprojection algorithm
X-Ray tomography is one of widespread methods of medical diagnostics. Due to its opportunity to visualize inside structure of scanned object it allows to diagnose, for example, cancer cells. Modern medical tomographic setups have lots of advantages such as high resolution, which allows to visualize objects of very small size, high level of reproducibility, which allows to verify obtained results, simplicity of utilization etc. There is certain amount of improvements still can be applied. One of most significant challenges is reducing of radiation dose. Diagnostics of complex structures sometimes requires more time of measurements. That means that dose will increase with time. This work proposes optimized filtered backprojection algorithm as solution for the problem of radiation dose level
Manipulation of immunometabolism by HIV-accessories to the crime?
Evolutionary pressure has produced an 'arms race' between cellular restriction factors (limiting viral replication) and viral proteins (overcoming host restriction). The host factors SAMHD1 and SLFN1 patrol metabolic bottlenecks required for HIV replication. Conversely, the HIV accessory proteins Vpx, Vpu and Nef manipulate cellular metabolism to enable viral replication. Recent work identifying Vpu-mediated downregulation of the alanine transporter SNAT1 and Nef-mediated downregulation of the serine carriers SERINC3/5 has uncovered the importance of HIV manipulation of the amino acid supply. Interference with CD4(+) T-cell amino acid metabolism suggests a novel paradigm of viral immunomodulation, and signposts fundamental aspects of lymphocyte biology.This work was supported by the NIHR Cambridge BRC, a Wellcome Trust Strategic Award to CIMR and the Addenbrooke’s Charitable Trust.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.coviro.2016.06.01
A marine biodiversity observation network for genetic monitoring of hard-bottom communities (ARMS-MBON)
Marine hard-bottom communities are undergoing severe change under the influence of multiple drivers, notably climate change, extraction of natural resources, pollution and eutrophication, habitat degradation, and invasive species. Monitoring marine biodiversity in such habitats is, however, challenging as it typically involves expensive, non-standardized, and often destructive sampling methods that limit its scalability. Differences in monitoring approaches furthermore hinders inter-comparison among monitoring programs. Here, we announce a Marine Biodiversity Observation Network (MBON) consisting of Autonomous Reef Monitoring Structures (ARMS) with the aim to assess the status and changes in benthic fauna with genomic-based methods, notably DNA metabarcoding, in combination with image-based identifications. This article presents the results of a 30-month pilot phase in which we established an operational and geographically expansive ARMS-MBON. The network currently consists of 20 observatories distributed across European coastal waters and the polar regions, in which 134 ARMS have been deployed to date. Sampling takes place annually, either as short-term deployments during the summer or as long-term deployments starting in spring. The pilot phase was used to establish a common set of standards for field sampling, genetic analysis, data management, and legal compliance, which are presented here. We also tested the potential of ARMS for combining genetic and image-based identification methods in comparative studies of benthic diversity, as well as for detecting non-indigenous species. Results show that ARMS are suitable for monitoring hard-bottom environments as they provide genetic data that can be continuously enriched, re-analyzed, and integrated with conventional data to document benthic community composition and detect non-indigenous species. Finally, we provide guidelines to expand the network and present a sustainability plan as part of the European Marine Biological Resource Centre (www.embrc.eu).Peer reviewe
Balancing selection is common in the extended MHC region but most alleles with opposite risk profile for autoimmune diseases are neutrally evolving
<p>Abstract</p> <p>Background</p> <p>Several susceptibility genetic variants for autoimmune diseases have been identified. A subset of these polymorphisms displays an opposite risk profile in different autoimmune conditions. This observation open interesting questions on the evolutionary forces shaping the frequency of these alleles in human populations.</p> <p>We aimed at testing the hypothesis whereby balancing selection has shaped the frequency of opposite risk alleles.</p> <p>Results</p> <p>Since balancing selection signatures are expected to extend over short genomic portions, we focused our analyses on 11 regions carrying putative functional polymorphisms that may represent the disease variants (and the selection targets). No exceptional nucleotide diversity was observed for <it>ZSCAN23</it>, <it>HLA-DMB</it>, <it>VARS2</it>, <it>PTPN22</it>, <it>BAT3</it>, <it>C6orf47</it>, and <it>IL10</it>; summary statistics were consistent with evolutionary neutrality for these gene regions. Conversely, <it>CDSN/PSORS1C1</it>, <it>TRIM10/TRIM40</it>, <it>BTNL2</it>, and <it>TAP2 </it>showed extremely high nucleotide diversity and most tests rejected neutrality, suggesting the action of balancing selection. For <it>TAP2 </it>and <it>BTNL2 </it>these signatures are not secondary to linkage disequilibrium with HLA class II genes. Nonetheless, with the exception of variants in <it>TRIM40 </it>and <it>CDSN</it>, our data suggest that opposite risk SNPs are not selection targets but rather have accumulated as neutral variants.</p> <p>Conclusion</p> <p>Data herein indicate that balancing selection is common within the extended MHC region and involves several non-HLA loci. Yet, the evolutionary history of most SNPs with an opposite effect for autoimmune diseases is consistent with evolutionary neutrality. We suggest that variants with an opposite effect on autoimmune diseases should not be considered a distinct class of disease alleles from the evolutionary perspective and, in a few cases, the opposite effect on distinct diseases may derive from complex haplotype structures in regions with high genetic diversity.</p
Genome Degradation in Brucella ovis Corresponds with Narrowing of Its Host Range and Tissue Tropism
Brucella ovis is a veterinary pathogen associated with epididymitis in sheep. Despite its genetic similarity to the zoonotic pathogens B. abortus, B. melitensis and B. suis, B. ovis does not cause zoonotic disease. Genomic analysis of the type strain ATCC25840 revealed a high percentage of pseudogenes and increased numbers of transposable elements compared to the zoonotic Brucella species, suggesting that genome degradation has occurred concomitant with narrowing of the host range of B. ovis. The absence of genomic island 2, encoding functions required for lipopolysaccharide biosynthesis, as well as inactivation of genes encoding urease, nutrient uptake and utilization, and outer membrane proteins may be factors contributing to the avirulence of B. ovis for humans. A 26.5 kb region of B. ovis ATCC25840 Chromosome II was absent from all the sequenced human pathogenic Brucella genomes, but was present in all of 17 B. ovis isolates tested and in three B. ceti isolates, suggesting that this DNA region may be of use for differentiating B. ovis from other Brucella spp. This is the first genomic analysis of a non-zoonotic Brucella species. The results suggest that inactivation of genes involved in nutrient acquisition and utilization, cell envelope structure and urease may have played a role in narrowing of the tissue tropism and host range of B. ovis
The CydDC family of transporters
The CydDC family of ABC transporters export the low molecular weight thiols glutathione and cysteine to the periplasm of a variety of bacterial species. The CydDC complex has previously been shown to be important for disulfide folding, motility, respiration, and tolerance to nitric oxide and antibiotics. In addition, CydDC is thus far unique amongst ABC transporters in that it binds a haem cofactor that appears to modulate ATPase activity. CydDC has a diverse impact upon bacterial metabolism, growth, and virulence, and is of interest to those working on membrane transport mechanisms, redox biology, aerobic respiration, and stress sensing/tolerance during infection
The great opportunity: Evolutionary applications to medicine and public health
Evolutionary biology is an essential basic science for medicine, but few doctors and medical researchers are familiar with its most relevant principles. Most medical schools have geneticists who understand evolution, but few have even one evolutionary biologist to suggest other possible applications. The canyon between evolutionary biology and medicine is wide. The question is whether they offer each other enough to make bridge building worthwhile. What benefits could be expected if evolution were brought fully to bear on the problems of medicine? How would studying medical problems advance evolutionary research? Do doctors need to learn evolution, or is it valuable mainly for researchers? What practical steps will promote the application of evolutionary biology in the areas of medicine where it offers the most? To address these questions, we review current and potential applications of evolutionary biology to medicine and public health. Some evolutionary technologies, such as population genetics, serial transfer production of live vaccines, and phylogenetic analysis, have been widely applied. Other areas, such as infectious disease and aging research, illustrate the dramatic recent progress made possible by evolutionary insights. In still other areas, such as epidemiology, psychiatry, and understanding the regulation of bodily defenses, applying evolutionary principles remains an open opportunity. In addition to the utility of specific applications, an evolutionary perspective fundamentally challenges the prevalent but fundamentally incorrect metaphor of the body as a machine designed by an engineer. Bodies are vulnerable to disease – and remarkably resilient – precisely because they are not machines built from a plan. They are, instead, bundles of compromises shaped by natural selection in small increments to maximize reproduction, not health. Understanding the body as a product of natural selection, not design, offers new research questions and a framework for making medical education more coherent. We conclude with recommendations for actions that would better connect evolutionary biology and medicine in ways that will benefit public health. It is our hope that faculty and students will send this article to their undergraduate and medical school Deans, and that this will initiate discussions about the gap, the great opportunity, and action plans to bring the full power of evolutionary biology to bear on human health problems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90555/1/j.1752-4571.2007.00006.x.pd
Trans-species polymorphism in humans and the great apes is generally maintained by balancing selection that modulates the host immune response
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