What's new for 'Trypanosomatids' in PubMed

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Sent on Friday, 2012 April 06
Search: kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"

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PubMed Results

Items 1 - 10 of 10

1.	PLoS One. 2012;7(3):e34143. Epub 2012 Mar 30. B Cell: T Cell Interactions Occur within Hepatic Granulomas during Experimental Visceral Leishmaniasis. Moore JW, Beattie L, Dalton JE, Owens BM, Maroof A, Coles MC, Kaye PM . Source Centre for Immunology and Infection, Hull York Medical School and Department of Biology, University of York, Heslington, York, United Kingdom. Abstract Hepatic resistance to Leishmania donovani infection in mice is associated with the development of granulomas, in which a variety of lymphoid and non-lymphoid populations accumulate. Although previous studies have identified B cells in hepatic granulomas and functional studies in B cell-deficient mice have suggested a role for B cells in the control of experimental visceral leishmaniasis, little is known about the behaviour of B cells in the granuloma microenvironment. Here, we first compared the hepatic B cell population in infected mice, where ≈60% of B cells are located within granulomas, with that of naïve mice. In infected mice, there was a small increase in mIgM(lo)mIgD(+) mature B2 cells, but no enrichment of B cells with regulatory phenotype or function compared to the naïve hepatic B cell population, as assessed by CD1d and CD5 expression and by IL-10 production. Using 2-photon microscopy to quantify the entire intra-granuloma B cell population, in conjunction with the adoptive transfer of polyclonal and HEL-specific BCR-transgenic B cells isolated from L. donovani-infected mice, we demonstrated that B cells accumulate in granulomas over time in an antigen-independent manner. Intra-vital dynamic imaging was used to demonstrate that within the polyclonal B cell population obtained from L. donovani-infected mice, the frequency of B cells that made multiple long contacts with endogenous T cells was greater than that observed using HEL-specific B cells obtained from the same inflammatory environment. These data indicate, therefore, that a subset of this polyclonal B cell population is capable of making cognate interactions with T cells within this unique environment, and provide the first insights into the dynamics of B cells within an inflammatory site.
	PMID: 22479545 [PubMed - in process]
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2.	PLoS One. 2012;7(3):e34022. Epub 2012 Mar 30. Leishmania amazonensis Arginase Compartmentalization in the Glycosome Is Important for Parasite Infectivity. da Silva MF, Zampieri RA, Muxel SM, Beverley SM, Floeter-Winter LM. Source Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil. Abstract In Leishmania, de novo polyamine synthesis is initiated by the cleavage of L-arginine to urea and L-ornithine by the action of arginase (ARG, E.C. 3.5.3.1). Previous studies in L. major and L. mexicana showed that ARG is essential for in vitro growth in the absence of polyamines and needed for full infectivity in animal infections. The ARG protein is normally found within the parasite glycosome, and here we examined whether this localization is required for survival and infectivity. First, the localization of L. amazonensis ARG in the glycosome was confirmed in both the promastigote and amastigote stages. As in other species, arg(-) L. amazonensis required putrescine for growth and presented an attenuated infectivity. Restoration of a wild type ARG to the arg(-) mutant restored ARG expression, growth and infectivity. In contrast, restoration of a cytosol-targeted ARG lacking the glycosomal SKL targeting sequence (argΔSKL) restored growth but failed to restore infectivity. Further study showed that the ARGΔSKL protein was found in the cytosol as expected, but at very low levels. Our results indicate that the proper compartmentalization of L. amazonensis arginase in the glycosome is important for enzyme activity and optimal infectivity. Our conjecture is that parasite arginase participates in a complex equilibrium that defines the fate of L-arginine and that its proper subcellular location may be essential for this physiological orchestration.
	PMID: 22479507 [PubMed - in process]
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3.	PLoS Biol. 2012 Mar;10(3):e1001287. Epub 2012 Mar 27. NUP-1 Is a Large Coiled-Coil Nucleoskeletal Protein in Trypanosomes with Lamin-Like Functions. Dubois KN, Alsford S, Holden JM, Buisson J, Swiderski M, Bart JM, Ratushny AV, Wan Y, Bastin P, Barry JD, Navarro M, Horn D, Aitchison JD, Rout MP, Field MC. Source Department of Pathology, University of Cambridge, Cambridge, United Kingdom. Abstract A unifying feature of eukaryotic nuclear organization is genome segregation into transcriptionally active euchromatin and transcriptionally repressed heterochromatin. In metazoa, lamin proteins preserve nuclear integrity and higher order heterochromatin organization at the nuclear periphery, but no non-metazoan lamin orthologues have been identified, despite the likely presence of nucleoskeletal elements in many lineages. This suggests a metazoan-specific origin for lamins, and therefore that distinct protein elements must compose the nucleoskeleton in other lineages. The trypanosomatids are highly divergent organisms and possess well-documented but remarkably distinct mechanisms for control of gene expression, including polycistronic transcription and trans-splicing. NUP-1 is a large protein localizing to the nuclear periphery of Trypanosoma brucei and a candidate nucleoskeletal component. We sought to determine if NUP-1 mediates heterochromatin organization and gene regulation at the nuclear periphery by examining the influence of NUP-1 knockdown on morphology, chromatin positioning, and transcription. We demonstrate that NUP-1 is essential and part of a stable network at the inner face of the trypanosome nuclear envelope, since knockdown cells have abnormally shaped nuclei with compromised structural integrity. NUP-1 knockdown also disrupts organization of nuclear pore complexes and chromosomes. Most significantly, we find that NUP-1 is required to maintain the silenced state of developmentally regulated genes at the nuclear periphery; NUP-1 knockdown results in highly specific mis-regulation of telomere-proximal silenced variant surface glycoprotein (VSG) expression sites and procyclin loci, indicating a disruption to normal chromatin organization essential to life-cycle progression. Further, NUP-1 depletion leads to increased VSG switching and therefore appears to have a role in control of antigenic variation. Thus, analogous to vertebrate lamins, NUP-1 is a major component of the nucleoskeleton with key roles in organization of the nuclear periphery, heterochromatin, and epigenetic control of developmentally regulated loci.
	PMID: 22479148 [PubMed - in process]
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4.	Parasitol Res. 2012 Apr 4. [Epub ahead of print] Adulticide effect of Monticalia greenmaniana (Asteraceae) against Lutzomyia migonei (Diptera: Psychodidae). Cárdenas J, Rojas J, Rondón M, Nieves E. Source LAPEX-Experimental Parasitology Laboratory, Biology Department, Science Faculty, Universidad de Los Andes, Merida, Venezuela. Abstract Leishmaniasis is a public health problem that has been increasing year by year, with the further difficulty that an efficient control system is not available. Therefore, it is necessary to search for less contaminating and dangerous alternatives for controlling Leishmania transmitting sandflies. The purpose of this study was to evaluate the activity of Monticalia greenmaniana (Asteraceae) extracts and essential oil as an adulticide against Lutzomyia migonei (Diptera: Psychodidae) females, from a laboratory colony, in experimental conditions. Dry aerial parts of M. greenmaniana (Hieron) Jeffrey were used. Methanolic and aqueous extracts were prepared, and essential oil was obtained by hydrodistillation. Adulticide tests in pots, adulticide tests in cages, and knocked-down effects were determined. The results obtained demonstrated that methanolic and aqueous extracts produced adulticide activity. The essential oil from M. greenmaniana was proved to be the most toxic against L. migonei, with a 95 % death rate at a concentration of 0.01 mg/ml during a 1-h exposure. The essential oil showed a DL50 = 0.0050 and DL98 = 0.0066 mg/ml. The methanolic extract was DL50 = 0.130 and DL98 = 1.016 mg/ml, and the aqueous extract, DL50 = 0.487 and DL98 10.924 mg/ml. The knocked-down effect for the M. greenmaniana oil showed a KDTL50 = 48.6 and KDTL98 = 90.1 min. It was concluded that the essential oil from M. greenmaniana showed a strong insecticide effect against L. migonei females, which encourages us to continue these studies in search for control alternatives against sandflies.
	PMID: 22476600 [PubMed - as supplied by publisher]
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5.	Parasitol Res. 2012 Apr 4. [Epub ahead of print] Previous exposure to a low infectious dose of Leishmania major exacerbates infection with Leishmania infantum in the susceptible BALB/c mouse. Nation CS, Dondji B, Stryker GA. Source Department of Biological Sciences, Central Washington University, 400E University Way, Ellensburg, WA, 98926, USA. Abstract The geographic distribution of Leishmania major overlaps with several other species of Leishmania. This study seeks to examine what effect previous exposure to L. major has on the outcome of infection with Leishmania infantum, the agent of virulent visceral leishmaniasis. The L. major immune response is well characterized by a strong Th1 response leading to resolution and protection against subsequent re-infection. A contrasting Th2 immune response leads to disseminated disease, while the role Th17 cytokines may play in Leishmania infection is still being explored. The cytokine profile, antibody titer, and parasite burden were evaluated in the susceptible BALB/c mouse after L. infantum infection in either naïve mice or those previously infected with a low/self-healing dose of L. major. Only IL-4 expression in mice previously exposed to L. major was found to be significantly increased over controls, a cytokine with an ambiguous role in L. infantum infection. However, disease exacerbation, with a notably higher parasite burden, was observed in the L. major exposed mice compared to the L. infantum only. Cross-reactive antibodies were seen in both groups of infected mice regardless of their immune history. Studies have shown a role for opsonizing antibodies leading to increased disease in visceral leishmaniasis. We speculate that cross-reactive antibodies may be playing a role in augmenting visceral disease in mice with immunological memory to L. major.
	PMID: 22476599 [PubMed - as supplied by publisher]
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6.	Vaccine. 2012 Apr 1. [Epub ahead of print] Leishmaniasis: Vaccine candidates and perspectives. Singh B, Sundar S. Source Infectious Disease Research Laboratory, Department of Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221 005, UP, India. Abstract Leishmania is a protozoan parasite and a causative agent of the various clinical forms of leishmaniasis. High cost, resistance and toxic side effects of traditional drugs entail identification and development of therapeutic alternatives. The sound understanding of parasite biology is key for identifying novel drug targets, that can induce the cell mediated immunity (mainly CD4+ and CD8+ IFN-gamma mediated responses) polarized towards a Th1 response. These aspects are important in designing a new vaccine along with the consideration of the candidates with respect to their ability to raise memory response in order to improve the vaccine performance. This review is an effort to identify molecules according to their homology with the host and their ability to be used as potent vaccine candidates. Copyright © 2012. Published by Elsevier Ltd.
	PMID: 22475861 [PubMed - as supplied by publisher]
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7.	Parasitology. 2012 Apr 4:1-10. [Epub ahead of print] Proteomics and the Trypanosoma brucei cytoskeleton: advances and opportunities. Portman N, Gull K. Source The Sir William Dunn School of Pathology and Oxford Centre for Integrative Systems Biology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK. Abstract SUMMARYTrypanosoma brucei is the etiological agent of devastating parasitic disease in humans and livestock in sub-saharan Africa. The pathogenicity and growth of the parasite are intimately linked to its shape and form. This is in turn derived from a highly ordered microtubule cytoskeleton that forms a tightly arrayed cage directly beneath the pellicular membrane and numerous other cytoskeletal structures such as the flagellum. The parasite undergoes extreme changes in cellular morphology during its life cycle and cell cycles which require a high level of integration and coordination of cytoskeletal processes. In this review we will discuss the role that proteomics techniques have had in advancing our understanding of the molecular composition of the cytoskeleton and its functions. We then consider future opportunities for the application of these techniques in terms of addressing some of the unanswered questions of trypanosome cytoskeletal cell biology with particular focus on the differences in the composition and organisation of the cytoskeleton through the trypanosome life-cycle.
	PMID: 22475638 [PubMed - as supplied by publisher]
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8.	Epidemiol Infect. 2012 Apr 4:1-4. [Epub ahead of print] The persisting burden of visceral leishmaniasis in Iraq: data of the National Surveillance System, 1990-2009. Majeed B, Sobel J, Nawar A, Badri S, Muslim H. Source Centers for Disease Control and Prevention, Center for Global Health, Atlanta, GA, USA. Abstract SUMMARYVisceral leishmaniasis (VL) is an endemic parasitic disease transmitted by the bite of sand flies. To describe trends and demographics of reported VL cases, we reviewed surveillance data from 1990-2009. Reported VL incidence per 100 000 population was 2·6 in 2007, 3·1 in 2008, and 4·8 in 2009, mostly in children aged <5 years. The number of cases varied greatly in step with prevailing economic and security conditions, raising concerns about the completeness and quality of surveillance data. Nevertheless, we conclude that VL remains an important endemic disease in Iraq and that surveillance system is recovering the capacity to detect cases as the country experiences greater stability. We recommend conducting formal entomological investigations, and evaluating existing control measures.
	PMID: 22475358 [PubMed - as supplied by publisher]
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9.	Nat Prod Commun. 2012 Feb;7(2):195-6. A double-blind, randomized, clinical trial on the antileishmanial activity of a Morinda citrifolia (Noni) stem extract and its major constituents. Sattar FA, Ahmed F, Ahmed N, Sattar SA, Malghani MA, Choudhary MI. Source Balochistan University of Information Technology, Engineering and Management Sciences, Quetta, Pakistan. fouzia.sattar@buitms.edu.pk Abstract A controlled study was conducted to determine the efficiency of a topical ointment prepared from the stem extract of Morinda citrifolia against cutaneous leishmaniasis. Similarly, the in vitro antileishmanial activity of morindicone and morinthone isolated from the extract were investigated against Leishmania major. These compounds displayed good activity. Out of 40 patients, 50% showed an excellent response and 30% exhibited good improvement.
	PMID: 22474954 [PubMed - in process]
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10.	JAAPA. 2011 Dec;24(12):18. Nodules that developed months after treatment. Al Aboud K, Al Aboud D. Source King Faisal Hospital, Makkah, Saudi Arabia.
	PMID: 22315912 [PubMed - indexed for MEDLINE]
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