What's new for 'Trypanosomatids' in PubMed

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Sent on Sunday, 2011 Apr 10
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 - 5 of 5

1.	J Biol Chem. 2011 Apr 7. [Epub ahead of print] Endonuclease associations with three distinct editosomes in Trypanosoma brucei. Carnes J, Zelaya Soares C, Wickham C, Stuart K. Seattle Biomedical Research Institute, United States. Abstract Three distinct editosomes, typified by mutually exclusive KREN1, KREN2 or KREN3 endonucleases, are essential for mitochondrial RNA editing in Trypanosoma brucei. The three editosomes differ in substrate endoribonucleolytic cleavage specificity, which may reflect the vast number of editing sites that need insertion or deletion of uridine nucleotides (Us). Each editosome requires the single RNase III domain in each of endonuclease for catalysis. Studies reported here show that the editing endonucleases do not form homodimeric domains, and may therefore function as intermolecular heterodimers, perhaps with KREPB4 and/or KREPB5. Editosomes isolated via TAP-tag fused to KREPB6, KREPB7 or KREPB8 have a common set of 12 proteins. In addition, KREN3 is only found in KREPB6 editosomes, KREN2 is only found in KREPB7 editosomes, and KREN1 is only found in KREPB8 editosomes. These are the same associations previously found in editosomes isolated via the TAP tagged endonucleases KREN1, KREN2, or KREN3. Furthermore, TAP-tagged KREPB6, KREPB7, and KREPB8 complexes isolated from cells in which expression of their respective endonuclease was knocked down were disrupted and lacked the heterotrimeric insertion subcomplex (KRET2, KREPA1, and KREL2). These results and published data suggest that KREPB6, KREPB7 and KREPB8 associate with the deletion subcomplex while the KREN1, KREN2 and KREN3 endonucleases associate with insertion subcomplex. Free Article
	PMID: 21474442 [PubMed - as supplied by publisher]
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2.	Bioorg Med Chem Lett. 2011 Jan 27. [Epub ahead of print] Potent antiprotozoal activity of a novel semi-synth etic berberine derivative. Bahar M, Deng Y, Zhu X, He S, Pandharkar T, Drew ME, Navarro-Vázquez A, Anklin C, Gil RR, Doskotch RW, Werbovetz KA, Kinghorn AD. College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, USA. Abstract Treatment of diseases such as African sleeping sickness and leishmaniasis often depends on relatively expensive or toxic drugs, and resistance to current chemotherapeutics is an issue in treating these diseases and malaria. In this study, a new semi-synthetic berberine analogue, 5,6-didehydro-8,8-diethyl-13-oxodihydroberberine chloride (1), showed nanomolar level potency against in vitro models of leishmaniasis, malaria, and trypanosomiasis as well as activity in an in vivo visceral leishmaniasis model. Since the synthetic starting material, berberine hemisulfate, is inexpensive, 8,8-dialkyl-substituted analogues of berberine may lead to a new class of affordable antiprotozoal compounds. Copyright © 2011. Published by Elsevier Ltd.
	PMID: 21474310 [PubMed - as supplied by publisher]
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3.	Trans R Soc Trop Med Hyg. 2011 Apr 5. [Epub ahead of print] The emergence of concurrent HIV-1/AIDS and visceral leishmaniasis in Northea st Brazil. Nascimento ET, Moura ML, Queiroz JW, Barroso AW, Araujo AF, Rego EF, Wilson ME, Pearson RD, Jeronimo SM. Department of Infectious Disease, Health Sciences Center, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil; Health Post-Graduate Program, Health Sciences Center, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil. Abstract HIV has become increasingly prevalent in the Northeast region of Brazil where Leishmania infantum chagasi is endemic, and concurrent AIDS and visceral leishmaniasis (VL) has emerged. In this study, persons with HIV/AIDS and VL (n=17) had a mean age of 37.3 years (range 29-53 years) compared with 12.5 years (1-80 years) for persons with VL alone (n=2836). Males accounted for 88% of cases with concurrent VL and AIDS and 65% of those with VL alone. The mean CD4 count and antileishmanial antibody titre were lower and recurrence of VL and death were more likely with co-infection. Considering the prevalences of L.i. chagasi and HIV in the region, this may herald the emergence of an important public health problem. Copyright © 2011 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.
	PMID: 21474157 [PubMed - as supplied by publisher]
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4.	Arch Biochem Biophys. 2011 Mar 15;507(2):287-95. Epub 2010 Dec 16. Tryparedoxin peroxidases from Trypanosoma cruzi: high efficiency in the catalytic elimination of hydrogen peroxide and peroxynitrite. Piñeyro MD, Arcari T, Robello C, Radi R, Trujillo M. Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay. Abstract During host cell infection, Trypanosoma cruzi parasites are exposed to reactive oxygen and nitrogen species. As part of their antioxidant defense systems, they express two tryparedoxin peroxidases (TXNPx), thiol-dependent peroxidases members of the peroxiredoxin family. In this work, we report a kinetic characterization of cytosolic (c-TXNPx) and mitochondrial (m-TXNPx) tryparedoxin peroxidases from T. cruzi. Both c-TXNPx and m-TXNPx rapidly reduced hydrogen peroxide (k=3.0 x 10⁷ and 6 x 10⁶ M⁻¹ s⁻¹ at pH 7.4 and 25 °C, respectively) and peroxynitrite (k=1.0 x 10⁶ and k=1.8 x 10⁷ M⁻¹ s⁻¹ at pH 7.4 and 25 °C, respectively). The reductive part of the catalytic cycle was also studied, and the rate constant for the reduction of c-TXNPx by tryparedoxin I was 1.3 x 10⁶ M⁻¹ s⁻¹. The catalytic role of two conserved cysteine residues in both TXNPxs was confirmed with the identification of Cys52 and Cys173 (in c-TXNPX) and Cys81 and Cys204 (in m-TXNPx) as the peroxidatic and resolving cysteines, respectively. Our results indicate that mitochondrial and cytosolic TXNPxs from T. cruzi are highly efficient peroxidases that reduce hydrogen peroxide and peroxynitrite, and contribute to the understanding of their role as virulence factors reported in vivo. Copyright © 2010 Elsevier Inc. All rights reserved.
	PMID: 21167808 [PubMed - indexed for MEDLINE]
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5.	Zoonoses Public Health. 2010 Dec;57(7-8):e76-80. Toxoplasma gondii and Trypanosoma cruzi antibodies in dogs from Virginia. Rosypal AC, Hill R, Lewis S, Braxton K, Zajac AM, Lindsay DS. Department of Natural Sciences and Mathematics, College of Science, Technology, Engineering and Mathematics, Johnson C. Smith University, Charlotte, NC 28216, USA. acrosypal@jcsu.edu Abstract Toxoplasma gondii and Trypanosoma cruzi are zoonotic protozoan parasites that cause disseminated infections in many vertebrate species. The present study determined the seroprevalence of T. gondii and Tr. cruzi in a population of dogs from Virginia. Serum samples were tested from 90 domestic dogs collected from animal shelters in Virginia. Using an indirect immunofluorescent antibody test, sera were examined at a 1 : 50 dilution and antibodies to T. gondii were found in 19 dogs (21%). Antibodies to Tr. cruzi were determined by qualitative immunochromatographic dipstick assay. One (1%) of the 90 dogs had Tr. cruzi antibodies and it was also seropositive for T. gondii. Our findings indicate that dogs are frequently exposed to T. gondii in Virginia, but that antibodies to Tr. cruzi are rare in the same geographical region.
	PMID: 20500504 [PubMed - indexed for MEDLINE]
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