scholarly journals Definition of constitutive and stage-enriched promoters in the rodent malaria parasite, Plasmodium yoelii

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Laura M. Bowman ◽  
Logan E. Finger ◽  
Kevin J. Hart ◽  
Scott E. Lindner
Keyword(s):  
Life Cycle ◽  
Gene Editing ◽  
Life Cycle Stage ◽  
Plasmodium Yoelii ◽  
Essential Elements ◽  
Host Immune Responses ◽  
Specific Effects ◽  
Or Gene ◽  
Definition Of ◽  
Targeted Recombination

Abstract Background Well-defined promoters are essential elements for genetic studies in all organisms, and enable controlled expression of endogenous genes, transgene expression, and gene editing. Despite this, there is a paucity of defined promoters for the rodent-infectious malaria parasites. This is especially true for Plasmodium yoelii, which is often used to study the mosquito and liver stages of malarial infection, as well as host immune responses to infection. Methods Here six promoters were selected from across the parasite’s life cycle (clag-a, dynein heavy chain delta, lap4, trap, uis4, lisp2) that have been invoked in the literature as controlling their genes in a stage-specific manner. A minimal promoter length for the constitutive pybip promoter that confers strong expression levels was also determined, which is useful for expression of reporters and gene editing enzymes. Results Instead, it was observed that these promoters confer stage-enriched gene control, as some parasites also effectively use these promoters in other stages. Thus, when used alone, these promoters could complicate the interpretation of results obtained from promoter swaps, stage-targeted recombination, or gene editing experiments. Conclusions Together these data indicate that achieving stage-specific effects, such as gene editing, is likely best done using a two-component system with independent promoter activities overlapping only in the intended life cycle stage.

scholarly journals Plasmodium yoelii Macrophage Migration Inhibitory Factor Is Necessary for Efficient Liver-Stage Development

2012 ◽  
Vol 80 (4) ◽  
pp. 1399-1407 ◽  
Author(s):  
Jessica L. Miller ◽  
Anke Harupa ◽  
Stefan H. I. Kappe ◽  
Sebastian A. Mikolajczak
Keyword(s):  
Life Cycle ◽  
Immune Responses ◽  
Macrophage Migration Inhibitory Factor ◽  
Plasmodium Yoelii ◽  
Blood Stage ◽  
Macrophage Migration ◽  
Liver Stage ◽  
Content Type ◽  
Host Immune Responses ◽  
Stage Development

ABSTRACTMammalian macrophage migration inhibitory factor (MIF) is a multifaceted cytokine involved in both extracellular and intracellular functions. Malaria parasites express a MIF homologue that might modulate host immune responses against blood-stage parasites, but the potential importance of MIF against other life cycle stages remains unstudied. In this study, we characterized the MIF homologue ofPlasmodium yoeliithroughout the life cycle, with emphasis on preerythrocytic stages.P. yoeliiMIF (Py-MIF) was expressed in blood-stage parasites and detected at low levels in mosquito salivary gland sporozoites. MIF expression was strong throughout liver-stage development and localized to the cytoplasm of the parasite, with no evidence of release into the host hepatocyte. To examine the importance of Py-MIF for liver-stage development, we generated a Py-mifknockout parasite (P. yoeliiΔmif).P. yoeliiΔmifparasites grew normally as asexual erythrocytic-stage parasites and showed normal infection of mosquitoes. In contrast, theP. yoeliiΔmifstrain was attenuated during the liver stage. Mice infected withP. yoeliiΔmifsporozoites either did not develop blood-stage parasitemia or exhibited a delay in the onset of blood-stage patency. Furthermore,P. yoeliiΔmifparasites exhibited growth retardationin vivo. Combined, the data indicate thatPlasmodiumMIF is important for liver-stage development ofP. yoelii, during which it is likely to play an intrinsic role in parasite development rather than modulating host immune responses to infection.

Assessment of the Culture of Care working with laboratory animals by using a comprehensive survey tool

2021 ◽  
pp. 002367722110144
Author(s):  
Thomas Bertelsen ◽  
Kirstine Øvlisen
Keyword(s):  
Performance Indicators ◽  
Essential Elements ◽  
Laboratory Animals ◽  
Survey Tool ◽  
Culture Of Care ◽  
Eu Directive ◽  
Comprehensive Picture ◽  
Comprehensive Survey ◽  
Definition Of ◽  
The Eu

The term Culture of Care, within the scientific community using laboratory animals, is being used more and more frequently after it was introduced in the EU Directive 2010/63/EU, where it is phrased as a ‘climate of care’, which became effective in national legislation from January 2013. However, there is a risk that the term could become a meaningless phrase if no agreed local definition of the term exists at the animal facility (called establishment in the EU Directive). This paper presents a comprehensive survey tool that provides a means to describe what the Culture of Care in an establishment looks like. The tool is one of the elements that can contribute to the overall picture of the culture; however, it cannot stand alone. Together with an evaluation of the effectiveness of the Culture of Care (e.g. key performance indicators) and a description of the outcomes and achievements in terms of animal welfare and the 3Rs (Replace, Reduce, Refine), the survey tool will constitute a comprehensive picture. The survey tool offers a multilevel and comprehensive view of different subcultures, presenting details on mindset and behaviour of the employees and the different relations within the culture, thus enabling the initiation of improvement projects if required. The tool addresses essential elements of a co-operative culture in terms of what we think, what we do and how we work together.

Identification of asset life cycle stage: case study in heavy-duty truck fleet

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Oscar Daniel Rivera Baena ◽  
Maria Valentina Clavijo Mesa ◽  
Carmen Elena Patino Rodriguez ◽  
Fernando Jesus Guevara Carazas
Keyword(s):  
Life Cycle ◽  
Design Methodology ◽  
Life Cycle Stage ◽  
Waste Collection ◽  
Content Type ◽  
Heavy Duty Truck ◽  
Maintenance Work ◽  
Operational Decision Making ◽  
The Moment

PurposeThis paper aims to determine the stage of the life cycle where the trucks of a waste collection fleet from a Colombian city are located through a reliability approach. The reliability analysis and the evaluation of curve of operational costs allow to know the moment in which it is necessary to make decisions regarding an asset, its maintenance or possible replacement.Design/methodology/approachFor a dataset presented as maintenance work orders, the time to failures (TTFs) for each vehicle in the fleet were calculated. Then, a probability density function for those TTFs was fitted to locate each vehicle in a region of the bathtub curve and to calculate the reliability of the whole fleet. A general functional analysis was also developed to understand the function of the vehicles.FindingsIt was possible to determine that the largest proportion of the fleet was in the final stage of the life cycle, in this sense, the entire fleet represent critical assets which in most of cases could be worth replacement or overhaul.Originality/valueIn this study, an address is exposed for the identification of critical equipment by reliability and statistical analysis. This analysis is also integrated with the maintenance management process. This is a broadly interested topic since it allows to support the maintenance and operational decision-making process, indicating the focus of resource allocation all over the entire asset life cycle.

Developmental gene expression in Leishmania donovani: differential cloning and analysis of an amastigote-stage-specific gene

1994 ◽  
Vol 14 (5) ◽  
pp. 2975-2984
Author(s):  
H Charest ◽  
G Matlashewski
Keyword(s):  
Life Cycle ◽  
Leishmania Donovani ◽  
Repetitive Sequences ◽  
Protozoan Parasite ◽  
Life Cycle Stage ◽  
Immune Serum ◽  
Sand Fly ◽  
Specific Gene ◽  
Reading Frame ◽  
Developmental Gene Expression

Leishmania protozoans are the causative agents of leishmaniasis, a major parasitic disease in humans. During their life cycle, Leishmania protozoans exist as flagellated promastigotes in the sand fly vector and as nonmotile amastigotes in the mammalian hosts. The promastigote-to-amastigote transformation occurs in the phagolysosomal compartment of the macrophage cell and is a critical step for the establishment of the infection. To study this cytodifferentiation process, we differentially screened an amastigote cDNA library with life cycle stage-specific cDNA probes and isolated seven cDNAs representing amastigote-specific transcripts. Five of these were closely related (A2 series) and recognized, by Northern (RNA) blot analyses, a 3.5-kb transcript in amastigotes and in amastigote-infected macrophages. Expression of the amastigote-specific A2 gene was induced in promastigotes when they were transferred from culture medium at 26 degrees C and pH 7.4 to medium at 37 degrees C and pH 4.5, conditions which mimic the macrophage phagolysosomal environment. A2 genes are clustered in tandem arrays, and a 6-kb fragment corresponding to a unit of the cluster was cloned and partially sequenced. An open reading frame found within the A2-transcribed region potentially encoded a 22-kDa protein containing repetitive sequences. The recombinant A2 protein produced in Escherichia coli cells was specifically recognized by immune serum from a patient with visceral leishmaniasis. The A2 protein repetitive element has strong homology with an S antigen of Plasmodium falciparum, the protozoan parasite responsible for malaria. Both the A2 protein of Leishmania donovani and the S antigen of P. falciparum are stage specific and developmentally expressed in mammalian hosts.

scholarly journals Effects of silver nanoparticles on the freshwater snailPhysa acuta: The role of test media and snails’ life cycle stage

2016 ◽  
Vol 36 (1) ◽  
pp. 243-253 ◽  
Author(s):  
Sandra F. Gonçalves ◽  
Maria D. Pavlaki ◽  
Rafael Lopes ◽  
Julia Hammes ◽  
Julián Alberto Gallego-Urrea ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Life Cycle ◽  
Life Cycle Stage

scholarly journals Environmental and Social Impact Assessment of Optimized Post-Tensioned Concrete Road Bridges

2020 ◽  
Vol 12 (10) ◽  
pp. 4265 ◽  
Author(s):  
Vicent Penadés-Plà ◽  
David Martínez-Muñoz ◽  
Tatiana García-Segura ◽  
Ignacio J. Navarro ◽  
Víctor Yepes
Keyword(s):  
Life Cycle ◽  
Impact Assessment ◽  
Social Impact ◽  
Sustainability Assessment ◽  
Life Cycle Stage ◽  
Social Impact Assessment ◽  
Weighting Method ◽  
Ecoinvent Database ◽  
The Social ◽  
Post Tensioned

Most of the definitions of sustainability include three basic pillars: economic, environmental, and social. The economic pillar has always been evaluated but not necessarily in the sense of economic sustainability. On the other hand, the environmental pillar is increasingly being considered, while the social pillar is weakly developed. Focusing on the environmental and social pillars, the use of methodologies to allow a wide assessment of these pillars and the integration of the assessment in a few understandable indicators is crucial. This article is structured into two parts. In the first part, a review of life cycle impact assessment methods, which allow a comprehensive assessment of the environmental and social pillars, is carried out. In the second part, a complete environmental and social sustainability assessment is made using the ecoinvent database and ReCiPe method, for the environmental pillar, and SOCA database and simple Social Impact Weighting method, for the social pillar. This methodology was used to compare three optimized bridges: two box-section post-tensioned concrete road bridges with a variety of initial and maintenance characteristics, and a pre-stressed concrete precast bridge. The results show that there is a high interrelation between the environmental and social impact for each life cycle stage.

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