2,085 research outputs found
Safety of low dose glucocorticoid treatment in rheumatoid arthritis: published evidence and prospective trial data
Adverse effects of glucocorticoids have been abundantly reported. Published reports on low dose glucocorticoid treatment show that few of the commonly held beliefs about their incidence, prevalence, and impact are supported by clear scientific evidence. Safety data from recent randomised controlled clinical trials of low dose glucocorticoid treatment in RA suggest that adverse effects associated with this drug are modest, and often not statistically different from those of placebo
The Plasmodium falciparum, Nima-related kinase Pfnek-4: a marker for asexual parasites committed to sexual differentiation
<b>Background</b>
Malaria parasites undergo, in the vertebrate host, a developmental switch from asexual replication to sexual differentiation leading to the formation of gametocytes, the only form able to survive in the mosquito vector. Regulation of the onset of the sexual phase remains largely unknown and represents an important gap in the understanding of the parasite's complex biology.
<b>Methods:</b>
The expression and function of the Nima-related kinase Pfnek-4 during the early sexual development of the human malaria parasite Plasmodium falciparum were investigated, using three types of transgenic Plasmodium falciparum 3D7 lines: (i) episomally expressing a Pfnek-4-GFP fusion protein under the control of its cognate pfnek-4 promoter; (ii) episomally expressing negative or positive selectable markers, yeast cytosine deaminase-uridyl phosphoribosyl transferase, or human dihydrofolate reductase, under the control of the pfnek-4 promoter; and (iii) lacking a functional pfnek-4 gene. Parasite transfectants were analysed by fluorescence microscopy and flow cytometry. In vitro growth rate and gametocyte formation were determined by Giemsa-stained blood smears.
<b>Results:</b>
The Pfnek-4-GFP protein was found to be expressed in stage II to V gametocytes and, unexpectedly, in a subset of asexual-stage parasites undergoing schizogony. Culture conditions stimulating gametocyte formation resulted in significant increase of this schizont subpopulation. Moreover, sorted asexual parasites expressing the Pfnek-4-GFP protein displayed elevated gametocyte formation when returned to in vitro culture in presence of fresh red blood cells, when compared to GFP- parasites from the same initial population. Negative selection of asexual parasites expressing pfnek-4 showed a marginal reduction in growth rate, whereas positive selection caused a marked reduction in parasitaemia, but was not sufficient to completely abolish proliferation. Pfnek-4- clones are not affected in their asexual growth and produced normal numbers of stage V gametocytes.
<b>Conclusions:</b>
The results indicate that Pfnek-4 is not strictly gametocyte-specific, and is expressed in a small subset of asexual parasites displaying high rate conversion to sexual development. Pfnek-4 is not required for erythrocytic schizogony and gametocytogenesis. This is the first study to report the use of a molecular marker for the sorting of sexually-committed schizont stage P. falciparum parasites, which opens the way to molecular characterization of this pre-differentiated subpopulation
A transcriptomic snapshot of early molecular communication between Pasteuria penetrans and Meloidogyne incognita
© The Author(s). 2018Background: Southern root-knot nematode Meloidogyne incognita (Kofoid and White, 1919), Chitwood, 1949 is a key pest of agricultural crops. Pasteuria penetrans is a hyperparasitic bacterium capable of suppressing the nematode reproduction, and represents a typical coevolved pathogen-hyperparasite system. Attachment of Pasteuria endospores to the cuticle of second-stage nematode juveniles is the first and pivotal step in the bacterial infection. RNA-Seq was used to understand the early transcriptional response of the root-knot nematode at 8 h post Pasteuria endospore attachment. Results: A total of 52,485 transcripts were assembled from the high quality (HQ) reads, out of which 582 transcripts were found differentially expressed in the Pasteuria endospore encumbered J2 s, of which 229 were up-regulated and 353 were down-regulated. Pasteuria infection caused a suppression of the protein synthesis machinery of the nematode. Several of the differentially expressed transcripts were putatively involved in nematode innate immunity, signaling, stress responses, endospore attachment process and post-attachment behavioral modification of the juveniles. The expression profiles of fifteen selected transcripts were validated to be true by the qRT PCR. RNAi based silencing of transcripts coding for fructose bisphosphate aldolase and glucosyl transferase caused a reduction in endospore attachment as compared to the controls, whereas, silencing of aspartic protease and ubiquitin coding transcripts resulted in higher incidence of endospore attachment on the nematode cuticle. Conclusions: Here we provide evidence of an early transcriptional response by the nematode upon infection by Pasteuria prior to root invasion. We found that adhesion of Pasteuria endospores to the cuticle induced a down-regulated protein response in the nematode. In addition, we show that fructose bisphosphate aldolase, glucosyl transferase, aspartic protease and ubiquitin coding transcripts are involved in modulating the endospore attachment on the nematode cuticle. Our results add new and significant information to the existing knowledge on early molecular interaction between M. incognita and P. penetrans.Peer reviewedFinal Published versio
Wilson loops stability in the gauge/string correspondence
We study the stability of some classical string worldsheet solutions employed
for computing the potential energy between two static fundamental quarks in
confining and non-confining gravity duals. We discuss the fixing of the
diffeomorphism invariance of the string action, its relation with the
fluctuation orientation and the interpretation of the quark mass substraction
worldsheet needed for computing the potential energy in smooth (confining)
gravity background. We consider various dual gravity backgrounds and show by a
numerical analysis the existence of instabilities under linear fluctuations for
classical string embedding solutions having positive length function derivative
. Finally we make a brief discussion of 't Hooft loops in
non-conformal backgrounds.Comment: 34 pages, 36 figures. Reference added. Final version JHEP accepte
Science and technology parks as innovation intermediaries for green innovation
Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Springer in Lecture Notes in Mechanical Engineering on 18/08/2020.Available online: https://link.springer.com/chapter/10.1007/978-3-030-48021-9_101This paper discusses how science and technology parks (STPs) act as intermediaries for projects regarding green innovation. The empirical evidence is gathered through a case study of the City of Knowledge in Panama. For the recent Panama channel’s expansion, local authorities faced the need to improve the water resource management to secure enough fresh water for the canal’s operation. We inductively analysed data from 24 interviews, documents and participant observer. Preliminary results show the intermediation of STPs in green innovation processes in three phases: a first intermediation process is the STP as a hub for knowledge generation, including training for entrepreneurship. A second stage of the park as an innovation intermediary regards to an arena for knowledge and technology transfer, including collaboration with universities. A third phase implies financing and brokerage of green innovation between local and global actors. Our results challenge the existing literature about STPs with a narrow focus on economic spillover effects, or as hubs for attracting and developing cutting-edge technological innovations.acceptedVersio
Single-nucleotide polymorphism, linkage disequilibrium and geographic structure in the malaria parasite Plasmodium vivax: prospects for genome-wide association studies
<p>Abstract</p> <p>Background</p> <p>The ideal malaria parasite populations for initial mapping of genomic regions contributing to phenotypes such as drug resistance and virulence, through genome-wide association studies, are those with high genetic diversity, allowing for numerous informative markers, and rare meiotic recombination, allowing for strong linkage disequilibrium (LD) between markers and phenotype-determining loci. However, levels of genetic diversity and LD in field populations of the major human malaria parasite <it>P. vivax </it>remain little characterized.</p> <p>Results</p> <p>We examined single-nucleotide polymorphisms (SNPs) and LD patterns across a 100-kb chromosome segment of <it>P. vivax </it>in 238 field isolates from areas of low to moderate malaria endemicity in South America and Asia, where LD tends to be more extensive than in holoendemic populations, and in two monkey-adapted strains (Salvador-I, from El Salvador, and Belem, from Brazil). We found varying levels of SNP diversity and LD across populations, with the highest diversity and strongest LD in the area of lowest malaria transmission. We found several clusters of contiguous markers with rare meiotic recombination and characterized a relatively conserved haplotype structure among populations, suggesting the existence of recombination hotspots in the genome region analyzed. Both silent and nonsynonymous SNPs revealed substantial between-population differentiation, which accounted for ~40% of the overall genetic diversity observed. Although parasites clustered according to their continental origin, we found evidence for substructure within the Brazilian population of <it>P. vivax</it>. We also explored between-population differentiation patterns revealed by loci putatively affected by natural selection and found marked geographic variation in frequencies of nucleotide substitutions at the <it>pvmdr-1 </it>locus, putatively associated with drug resistance.</p> <p>Conclusion</p> <p>These findings support the feasibility of genome-wide association studies in carefully selected populations of <it>P. vivax</it>, using relatively low densities of markers, but underscore the risk of false positives caused by population structure at both local and regional levels.</p> <p>See commentary: <url>http://www.biomedcentral.com/1741-7007/8/90</url></p
Human surfactant protein D alters oxidative stress and HMGA1 expression to induce p53 apoptotic pathway in eosinophil leukemic cell line
This article is made available through the Brunel Open Access Publishing Fund. Copyright: © 2013 Mahajan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Surfactant protein D (SP-D), an innate immune molecule, has an indispensable role in host defense and regulation of
inflammation. Immune related functions regulated by SP-D include agglutination of pathogens, phagocytosis,
oxidative burst, antigen presentation, T lymphocyte proliferation, cytokine secretion, induction of apoptosis and
clearance of apoptotic cells. The present study unravels a novel ability of SP-D to reduce the viability of leukemic
cells (eosinophilic leukemic cell line, AML14.3D10; acute myeloid leukemia cell line, THP-1; acute lymphoid leukemia
cell lines, Jurkat, Raji; and human breast epithelial cell line, MCF-7), and explains the underlying mechanisms. SP-D
and a recombinant fragment of human SP-D (rhSP-D) induced G2/M phase cell cycle arrest, and dose and timedependent
apoptosis in the AML14.3D10 eosinophilic leukemia cell line. Levels of various apoptotic markers viz.
activated p53, cleaved caspase-9 and PARP, along with G2/M checkpoints (p21 and Tyr15 phosphorylation of cdc2)
showed significant increase in these cells. We further attempted to elucidate the underlying mechanisms of rhSP-D
induced apoptosis using proteomic analysis. This approach identified large scale molecular changes initiated by SPD
in a human cell for the first time. Among others, the proteomics analysis highlighted a decreased expression of
survival related proteins such as HMGA1, overexpression of proteins to protect the cells from oxidative burst, while a
drastic decrease in mitochondrial antioxidant defense system. rhSP-D mediated enhanced oxidative burst in
AML14.3D10 cells was confirmed, while antioxidant, N-acetyl-L-cysteine, abrogated the rhSP-D induced apoptosis.
The rhSP-D mediated reduced viability was specific to the cancer cell lines and viability of human PBMCs from
healthy controls was not affected. The study suggests involvement of SP-D in host’s immunosurveillance and
therapeutic potential of rhSP-D in the eosinophilic leukemia and cancers of other origins.Department of Biotechnology, Indi
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