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Sample records for brucei gambiense isolates

  1. Chimerization at the AQP2–AQP3 locus is the genetic basis of melarsoprol–pentamidine cross-resistance in clinical Trypanosoma brucei gambiense isolates

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    Fabrice E. Graf

    2015-08-01

    Full Text Available Aquaglyceroporin-2 is a known determinant of melarsoprol–pentamidine cross-resistance in Trypanosoma brucei brucei laboratory strains. Recently, chimerization at the AQP2–AQP3 tandem locus was described from melarsoprol–pentamidine cross-resistant Trypanosoma brucei gambiense isolates from sleeping sickness patients in the Democratic Republic of the Congo. Here, we demonstrate that reintroduction of wild-type AQP2 into one of these isolates fully restores drug susceptibility while expression of the chimeric AQP2/3 gene in aqp2–aqp3 null T. b. brucei does not. This proves that AQP2–AQP3 chimerization is the cause of melarsoprol–pentamidine cross-resistance in the T. b. gambiense isolates.

  2. Mechanism of Trypanosoma brucei gambiense resistance to human serum

    DEFF Research Database (Denmark)

    Uzureau, Pierrick; Uzureau, Sophie; Lecordier, Laurence;

    2013-01-01

    The African parasite Trypanosoma brucei gambiense accounts for 97% of human sleeping sickness cases. T. b. gambiense resists the specific human innate immunity acting against several other tsetse-fly-transmitted trypanosome species such as T. b. brucei, the causative agent of nagana disease......GP), which prevents APOL1 toxicity and induces stiffening of membranes upon interaction with lipids. Two additional features contribute to resistance to TLFs: reduction of sensitivity to APOL1 requiring cysteine protease activity, and TbHpHbR inactivation due to a L210S substitution. According...

  3. Genotypic status of the TbAT1/P2 adenosine transporter of Trypanosoma brucei gambiense isolates from Northwestern Uganda following melarsoprol withdrawal.

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    Anne J N Kazibwe

    Full Text Available BACKGROUND: The development of arsenical and diamidine resistance in Trypanosoma brucei is associated with loss of drug uptake by the P2 purine transporter as a result of alterations in the corresponding T. brucei adenosine transporter 1 gene (TbAT1. Previously, specific TbAT1 mutant type alleles linked to melarsoprol treatment failure were significantly more prevalent in T. b. gambiense from relapse patients at Omugo health centre in Arua district. Relapse rates of up to 30% prompted a shift from melarsoprol to eflornithine (alpha-difluoromethylornithine, DFMO as first-line treatment at this centre. The aim of this study was to determine the status of TbAT1 in recent isolates collected from T. b. gambiense sleeping sickness patients from Arua and Moyo districts in Northwestern Uganda after this shift in first-line drug choice. METHODOLOGY AND RESULTS: Blood and cerebrospinal fluids of consenting patients were collected for DNA preparation and subsequent amplification. All of the 105 isolates from Omugo that we successfully analysed by PCR-RFLP possessed the TbAT1 wild type allele. In addition, PCR/RFLP analysis was performed for 74 samples from Moyo, where melarsoprol is still the first line drug; 61 samples displayed the wild genotype while six were mutant and seven had a mixed pattern of both mutant and wild-type TbAT1. The melarsoprol treatment failure rate at Moyo over the same period was nine out of 101 stage II cases that were followed up at least once. Five of the relapse cases harboured mutant TbAT1, one had the wild type, while no amplification was achieved from the remaining three samples. CONCLUSIONS/SIGNIFICANCE: The apparent disappearance of mutant alleles at Omugo may correlate with melarsoprol withdrawal as first-line treatment. Our results suggest that melarsoprol could successfully be reintroduced following a time lag subsequent to its replacement. A field-applicable test to predict melarsoprol treatment outcome and identify

  4. Mechanism of Trypanosoma brucei gambiense (group 1) resistance to human trypanosome lytic factor.

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    Kieft, Rudo; Capewell, Paul; Turner, C Michael R; Veitch, Nicola J; MacLeod, Annette; Hajduk, Stephen

    2010-09-14

    Human innate immunity against most African trypanosomes, including Trypanosoma brucei brucei, is mediated by a minor subclass of toxic serum HDL, called trypanosome lytic factor-1 (TLF-1). This HDL contains two primate specific proteins, apolipoprotein L-1 and haptoglobin (Hp)-related protein, as well as apolipoprotein A-1. These assembled proteins provide a powerful defense against trypanosome infection. Trypanosoma brucei rhodesiense causes human African sleeping sickness because it has evolved an inhibitor of TLF-1, serum resistance-associated (SRA) protein. Trypanosoma brucei gambiense lacks the SRA gene, yet it infects humans. As transfection of T. b. gambiense (group 1) is not possible, we initially used in vitro-selected TLF-1-resistant T. b. brucei to examine SRA-independent mechanisms of TLF-1 resistance. Here we show that TLF-1 resistance in T. b. brucei is caused by reduced expression of the Hp/Hb receptor gene (TbbHpHbR). Importantly, T. b. gambiense (group 1) also showed a marked reduction in uptake of TLF-1 and a corresponding decrease in expression of T. b. gambiense Hp/Hb receptor (TbgHpHbR). Ectopic expression of TbbHpHbR in TLF-1-resistant T. b. brucei rescued TLF-1 uptake, demonstrating that decreased TbbHpHbR expression conferred TLF-1 resistance. Ectopic expression of TbgHpHbR in TLF-1-resistant T. b. brucei failed to rescue TLF-1 killing, suggesting that coding sequence changes altered Hp/Hb receptor binding affinity for TLF-1. We propose that the combination of coding sequence mutations and decreased expression of TbgHpHbR directly contribute to parasite evasion of human innate immunity and infectivity of group 1 T. b. gambiense. PMID:20805508

  5. The TgsGP gene is essential for resistance to human serum in Trypanosoma brucei gambiense.

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    Capewell, Paul; Clucas, Caroline; DeJesus, Eric; Kieft, Rudo; Hajduk, Stephen; Veitch, Nicola; Steketee, Pieter C; Cooper, Anneli; Weir, William; MacLeod, Annette

    2013-01-01

    Trypanosoma brucei gambiense causes 97% of all cases of African sleeping sickness, a fatal disease of sub-Saharan Africa. Most species of trypanosome, such as T. b. brucei, are unable to infect humans due to the trypanolytic serum protein apolipoprotein-L1 (APOL1) delivered via two trypanosome lytic factors (TLF-1 and TLF-2). Understanding how T. b. gambiense overcomes these factors and infects humans is of major importance in the fight against this disease. Previous work indicated that a failure to take up TLF-1 in T. b. gambiense contributes to resistance to TLF-1, although another mechanism is required to overcome TLF-2. Here, we have examined a T. b. gambiense specific gene, TgsGP, which had previously been suggested, but not shown, to be involved in serum resistance. We show that TgsGP is essential for resistance to lysis as deletion of TgsGP in T. b. gambiense renders the parasites sensitive to human serum and recombinant APOL1. Deletion of TgsGP in T. b. gambiense modified to uptake TLF-1 showed sensitivity to TLF-1, APOL1 and human serum. Reintroducing TgsGP into knockout parasite lines restored resistance. We conclude that TgsGP is essential for human serum resistance in T. b. gambiense. PMID:24098129

  6. The TgsGP gene is essential for resistance to human serum in Trypanosoma brucei gambiense.

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    Paul Capewell

    Full Text Available Trypanosoma brucei gambiense causes 97% of all cases of African sleeping sickness, a fatal disease of sub-Saharan Africa. Most species of trypanosome, such as T. b. brucei, are unable to infect humans due to the trypanolytic serum protein apolipoprotein-L1 (APOL1 delivered via two trypanosome lytic factors (TLF-1 and TLF-2. Understanding how T. b. gambiense overcomes these factors and infects humans is of major importance in the fight against this disease. Previous work indicated that a failure to take up TLF-1 in T. b. gambiense contributes to resistance to TLF-1, although another mechanism is required to overcome TLF-2. Here, we have examined a T. b. gambiense specific gene, TgsGP, which had previously been suggested, but not shown, to be involved in serum resistance. We show that TgsGP is essential for resistance to lysis as deletion of TgsGP in T. b. gambiense renders the parasites sensitive to human serum and recombinant APOL1. Deletion of TgsGP in T. b. gambiense modified to uptake TLF-1 showed sensitivity to TLF-1, APOL1 and human serum. Reintroducing TgsGP into knockout parasite lines restored resistance. We conclude that TgsGP is essential for human serum resistance in T. b. gambiense.

  7. Wild fauna as a probable animal reservoir for Trypanosoma brucei gambiense in Cameroon

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    Njiokou, F.; Laveissière, Claude; Simo, G.; Nkinin, S.; Grébaut, Pascal; Cuny, Gérard; Herder, Stéphane

    2006-01-01

    In order to Study the existence of a wild animal reservoir for Trypanosoma brucei gambiense in South Cameroon, blood was collected from wild animals in three human African trypanosomiasis foci and from a nonendemic control area. The 1142 wild animals sampled belonged to 36 different species pertaining to eight orders (407 primates, 347 artiodactyls, 265 rodents, 54 pangolins, 53 carnivores, 11 Saurians and crocodilians, and five hyraxes). QBC (R) and KIVI tests detected trypanosomes on 1.7% (...

  8. Latent Trypanosoma brucei gambiense foci in Uganda: a silent epidemic in children and adults?

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    Wastling, S L; Picozzi, K; Wamboga, C; VON Wissmann, B; Amongi-Accup, C; Wardrop, N A; Stothard, J R; Kakembo, A; Welburn, S C

    2011-10-01

    Trypanosoma brucei gambiense sleeping sickness follows a long asymptomatic phase and persists in ancient foci from which epidemic clinical disease arises. A putative focus of T. b. gambiense infections has been identified, initially in mothers and young children, on the Lake Albert shoreline of Western Uganda leading to mass screening of 6207 individuals in September 2008. T. b. gambiense infections were identified by Card Agglutination Test for Trypanosomiasis (CATT) and sub-species-specific PCR although parasitological methods failed to confirm any patent trypanosome infections. In April 2009, CATT positives were re-visited; diagnosis of individuals by CATT and PCR was unstable over the two time points and parasites remained undetected, even using mini Anion Exchange Centrifugation Technique (mAECT). These observations suggest the possibility of a silent focus of disease, where all infected individuals are in a latent stage, and highlight our limited understanding of the local natural history and disease progression of T. b. gambiense in children and adults. PMID:21554841

  9. Screening of Trypanosoma brucei gambiense in Domestic Livestock and Tsetse Flies from an Insular Endemic Focus (Luba, Equatorial Guinea)

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    Cordon-Obras, Carlos; García-Estébanez, Carmen; Ndong-Mabale, Nicolás; Abaga, Simón; Ndongo-Asumu, Pedro; Benito, Agustín; Cano, Jorge

    2010-01-01

    Background Sleeping sickness is spread over 36 Sub-Saharan African countries. In West and Central Africa, the disease is caused by Trypanosoma brucei gambiense, which produces a chronic clinical manifestation. The Luba focus (Bioko Island, Equatorial Guinea) has not reported autochthonous sleeping sickness cases since 1995, but given the complexity of the epidemiological cycle, the elimination of the parasite in the environment is difficult to categorically ensure. Methodology/Principal Findings The aim of this work is to assess, by a molecular approach (Polymerase Chain Reaction, PCR), the possible permanence of T. b. gambiense in the vector (Glossina spp.) and domestic fauna in order to improve our understanding of the epidemiological situation of the disease in an isolated focus considered to be under control. The results obtained show the absence of the parasite in peridomestic livestock but its presence, although at very low rate, in the vector. On the other hand, interesting entomological data highlight that an elevated concentration of tsetse flies was observed in two out of the ten villages considered to be in the focus. Conclusions These findings demonstrate that even in conditions of apparent control, a complete parasite clearance is difficult to achieve. Further investigations must be focused on animal reservoirs which could allow the parasites to persist without leading to human cases. In Luba, where domestic livestock are scarcer than other foci in mainland Equatorial Guinea, the epidemiological significance of wild fauna should be assessed to establish their role in the maintenance of the infection. PMID:20544031

  10. Molecular evidence of a Trypanosoma brucei gambiense sylvatic cycle in the human african trypanosomiasis foci of Equatorial Guinea.

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    Cordon-Obras, Carlos; Rodriguez, Yasmin Fermin; Fernandez-Martinez, Amalia; Cano, Jorge; Ndong-Mabale, Nicolas; Ncogo-Ada, Policarpo; Ndongo-Asumu, Pedro; Aparicio, Pilar; Navarro, Miguel; Benito, Agustin; Bart, Jean-Mathieu

    2015-01-01

    Gambiense trypanosomiasis is considered an anthroponotic disease. Consequently, control programs are generally aimed at stopping transmission of Trypanosoma brucei gambiense (T. b. gambiense) by detecting and treating human cases. However, the persistence of numerous foci despite efforts to eliminate this disease questions this strategy as unique tool to pursue the eradication. The role of animals as a reservoir of T. b. gambiense is still controversial, but could partly explain maintenance of the infection at hypo-endemic levels. In the present study, we evaluated the presence of T. b. gambiense in wild animals in Equatorial Guinea. The infection rate ranged from 0.8% in the insular focus of Luba to more than 12% in Mbini, a focus with a constant trickle of human cases. The parasite was detected in a wide range of animal species including four species never described previously as putative reservoirs. Our study comes to reinforce the hypothesis that animals may play a role in the persistence of T. b. gambiense transmission, being particularly relevant in low transmission settings. Under these conditions the integration of sustained vector control and medical interventions should be considered to achieve the elimination of gambiense trypanosomiasis.

  11. Molecular evidence of a Trypanosoma brucei gambiense sylvatic cycle in the human african trypanosomiasis foci of Equatorial Guinea

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    Cordon-Obras, Carlos; Rodriguez, Yasmin Fermin; Fernandez-Martinez, Amalia; Cano, Jorge; Ndong-Mabale, Nicolas; Ncogo-Ada, Policarpo; Ndongo-Asumu, Pedro; Aparicio, Pilar; Navarro, Miguel; Benito, Agustin; Bart, Jean-Mathieu

    2015-01-01

    Gambiense trypanosomiasis is considered an anthroponotic disease. Consequently, control programs are generally aimed at stopping transmission of Trypanosoma brucei gambiense (T. b. gambiense) by detecting and treating human cases. However, the persistence of numerous foci despite efforts to eliminate this disease questions this strategy as unique tool to pursue the eradication. The role of animals as a reservoir of T. b. gambiense is still controversial, but could partly explain maintenance of the infection at hypo-endemic levels. In the present study, we evaluated the presence of T. b. gambiense in wild animals in Equatorial Guinea. The infection rate ranged from 0.8% in the insular focus of Luba to more than 12% in Mbini, a focus with a constant trickle of human cases. The parasite was detected in a wide range of animal species including four species never described previously as putative reservoirs. Our study comes to reinforce the hypothesis that animals may play a role in the persistence of T. b. gambiense transmission, being particularly relevant in low transmission settings. Under these conditions the integration of sustained vector control and medical interventions should be considered to achieve the elimination of gambiense trypanosomiasis. PMID:26257727

  12. Molecular Evidence of a Trypanosoma brucei gambiense Sylvatic Cycle in the Human African Trypanosomiasis Foci of Equatorial Guinea

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    Carlos eCordon-Obras

    2015-07-01

    Full Text Available Gambiense trypanosomiasis is considered an anthroponotic disease. Consequently, control programs are generally aimed at stopping transmission of Trypanosoma brucei gambiense (T. b. gambiense by detecting and treating human cases. However, the persistence of numerous foci despite efforts to eliminate this disease questions this strategy as unique tool to pursue the eradication. The role of animals as a reservoir of T. b. gambiense is still controversial, but could partly explain maintenance of the infection at hypo-endemic levels. In the present study, we evaluated the presence of T. b. gambiense in wild animals in Equatorial Guinea. The infection rate ranged from 0.8% in the insular focus of Luba to more than 12% in Mbini, a focus with a constant trickle of human cases. The parasite was detected in a wide range of animal species including four species never described previously as putative reservoirs. Our study comes to reinforce the hypothesis that animals may play a role in the persistence of T. b. gambiense transmission, being particularly relevant in low transmission settings. Under these conditions the integration of sustained vector control and medical interventions should be considered to achieve the elimination of Gambiense trypanosomiasis.

  13. Trypanosoma brucei gambiense Adaptation to Different Mammalian Sera Is Associated with VSG Expression Site Plasticity

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    Cordon-Obras, Carlos; Cano, Jorge; González-Pacanowska, Dolores; Benito, Agustin; Navarro, Miguel; Bart, Jean-Mathieu

    2013-01-01

    Trypanosoma brucei gambiense infection is widely considered an anthroponosis, although it has also been found in wild and domestic animals. Thus, fauna could act as reservoir, constraining the elimination of the parasite in hypo-endemic foci. To better understand the possible maintenance of T. b. gambiense in local fauna and investigate the molecular mechanisms underlying adaptation, we generated adapted cells lines (ACLs) by in vitro culture of the parasites in different mammalian sera. Using specific antibodies against the Variant Surface Glycoproteins (VSGs) we found that serum ACLs exhibited different VSG variants when maintained in pig, goat or human sera. Although newly detected VSGs were independent of the sera used, the consistent appearance of different VSGs suggested remodelling of the co-transcribed genes at the telomeric Expression Site (VSG-ES). Thus, Expression Site Associated Genes (ESAGs) sequences were analysed to investigate possible polymorphism selection. ESAGs 6 and 7 genotypes, encoding the transferrin receptor (TfR), expressed in different ACLs were characterised. In addition, we quantified the ESAG6/7 mRNA levels and analysed transferrin (Tf) uptake. Interestingly, the best growth occurred in pig and human serum ACLs, which consistently exhibited a predominant ESAG7 genotype and higher Tf uptake than those obtained in calf and goat sera. We also detected an apparent selection of specific ESAG3 genotypes in the pig and human serum ACLs, suggesting that other ESAGs could be involved in the host adaptation processes. Altogether, these results suggest a model whereby VSG-ES remodelling allows the parasite to express a specific set of ESAGs to provide selective advantages in different hosts. Finally, pig serum ACLs display phenotypic adaptation parameters closely related to human serum ACLs but distinct to parasites grown in calf and goat sera. These results suggest a better suitability of swine to maintain T. b. gambiense infection supporting

  14. In vitro investigation of Brazilian Cerrado plant extract activity against Plasmodium falciparum, Trypanosoma cruzi and T. brucei gambiense.

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    Charneau, Sébastien; de Mesquita, Mariana Laundry; Bastos, Izabela Marques Dourado; Santana, Jaime Martins; de Paula, José Elias; Grellier, Philippe; Espindola, Laila Salmen

    2016-06-01

    The threatened Brazilian Cerrado biome is an important biodiversity hotspot but still few explored that constitutes a potential reservoir of molecules to treat infectious diseases. We selected eight Cerrado plant species for screening against the erythrocytic stages of Plasmodium falciparum, human intracellular stages of Trypanosoma cruzi and bloodstream forms of T. brucei gambiense, and for their cytotoxicity upon the rat L6-myoblast cell line. Bioassays were performed with 37 hexane, ethyl acetate and ethanol extracts prepared from different plant organs. Activities against parasites were observed for 24 extracts: 9 with anti-P. falciparum, 4 with anti-T. cruzi and 11 with anti-T. brucei gambiense activities. High anti-protozoal activity (IC50 values knowledge essential for Cerrado conservation and sustainable development. PMID:26222897

  15. Untreated human infections by Trypanosoma brucei gambiense are not 100% fatal.

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    Vincent Jamonneau

    Full Text Available The final outcome of infection by Trypanosoma brucei gambiense, the main agent of sleeping sickness, has always been considered as invariably fatal. While scarce and old reports have mentioned cases of self-cure in untreated patients, these studies suffered from the lack of accurate diagnostic tools available at that time. Here, using the most specific and sensitive tools available to date, we report on a long-term follow-up (15 years of a cohort of 50 human African trypanosomiasis (HAT patients from the Ivory Coast among whom 11 refused treatment after their initial diagnosis. In 10 out of 11 subjects who continued to refuse treatment despite repeated visits, parasite clearance was observed using both microscopy and polymerase chain reaction (PCR. Most of these subjects (7/10 also displayed decreasing serological responses, becoming progressively negative to trypanosome variable antigens (LiTat 1.3, 1.5 and 1.6. Hence, in addition to the "classic" lethal outcome of HAT, we show that alternative natural progressions of HAT may occur: progression to an apparently aparasitaemic and asymptomatic infection associated with strong long-lasting serological responses and progression to an apparently spontaneous resolution of infection (with negative results in parasitological tests and PCR associated with a progressive drop in antibody titres as observed in treated cases. While this study does not precisely estimate the frequency of the alternative courses for this infection, it is noteworthy that in the field national control programs encounter a significant proportion of subjects displaying positive serologic test results but negative results in parasitological testing. These findings demonstrate that a number of these subjects display such infection courses. From our point of view, recognising that trypanotolerance exists in humans, as is now widely accepted for animals, is a major step forward for future research in the field of HAT.

  16. Loop Mediated Isothermal Amplification for Detection of Trypanosoma brucei gambiense in Urine and Saliva Samples in Nonhuman Primate Model

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    Maina Ngotho

    2015-01-01

    Full Text Available Human African trypanosomiasis (HAT is a vector-borne parasitic zoonotic disease. The disease caused by Trypanosoma brucei gambiense is the most prevalent in Africa. Early diagnosis is hampered by lack of sensitive diagnostic techniques. This study explored the potential of loop mediated isothermal amplification (LAMP and polymerase chain reaction (PCR in the detection of T. b. gambiense infection in a vervet monkey HAT model. Six vervet monkeys were experimentally infected with T. b. gambiense IL3253 and monitored for 180 days after infection. Parasitaemia was scored daily. Blood, cerebrospinal fluid (CSF, saliva, and urine samples were collected weekly. PCR and LAMP were performed on serum, CSF, saliva, and urine samples. The detection by LAMP was significantly higher than that of parasitological methods and PCR in all the samples. The performance of LAMP varied between the samples and was better in serum followed by saliva and then urine samples. In the saliva samples, LAMP had 100% detection between 21 and 77 dpi, whereas in urine the detection it was slightly lower, but there was over 80% detection between 28 and 91 dpi. However, LAMP could not detect trypanosomes in either saliva or urine after 140 and 126 dpi, respectively. The findings of this study emphasize the importance of LAMP in diagnosis of HAT using saliva and urine samples.

  17. Loop Mediated Isothermal Amplification for Detection of Trypanosoma brucei gambiense in Urine and Saliva Samples in Nonhuman Primate Model.

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    Ngotho, Maina; Kagira, John Maina; Gachie, Beatrice Muthoni; Karanja, Simon Muturi; Waema, Maxwell Wambua; Maranga, Dawn Nyawira; Maina, Naomi Wangari

    2015-01-01

    Human African trypanosomiasis (HAT) is a vector-borne parasitic zoonotic disease. The disease caused by Trypanosoma brucei gambiense is the most prevalent in Africa. Early diagnosis is hampered by lack of sensitive diagnostic techniques. This study explored the potential of loop mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR) in the detection of T. b. gambiense infection in a vervet monkey HAT model. Six vervet monkeys were experimentally infected with T. b. gambiense IL3253 and monitored for 180 days after infection. Parasitaemia was scored daily. Blood, cerebrospinal fluid (CSF), saliva, and urine samples were collected weekly. PCR and LAMP were performed on serum, CSF, saliva, and urine samples. The detection by LAMP was significantly higher than that of parasitological methods and PCR in all the samples. The performance of LAMP varied between the samples and was better in serum followed by saliva and then urine samples. In the saliva samples, LAMP had 100% detection between 21 and 77 dpi, whereas in urine the detection it was slightly lower, but there was over 80% detection between 28 and 91 dpi. However, LAMP could not detect trypanosomes in either saliva or urine after 140 and 126 dpi, respectively. The findings of this study emphasize the importance of LAMP in diagnosis of HAT using saliva and urine samples.

  18. Trypanosoma brucei gambiense Infections in Mice Lead to Tropism to the Reproductive Organs, and Horizontal and Vertical Transmission.

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    Biteau, Nicolas; Asencio, Corinne; Izotte, Julien; Rousseau, Benoit; Fèvre, Muriel; Pillay, Davita; Baltz, Théo

    2016-01-01

    Trypanosoma brucei gambiense, transmitted by the tsetse fly, is the main causative agent of Human African trypanosomosis in West Africa and poses a significant health risk to 70 million people. Disease progression varies depending on host immunity, but usually begins with a haemo-lymphatic phase, followed by parasite invasion of the central nervous system. In the current study, the tropism of T. b. gambiense 1135, causing a low level chronic 'silent' infection, was monitored in a murine model using bioluminescence imaging and PCR. A tropism to the reproductive organs, in addition to the central nervous system, after 12-18 months of infection was observed. Bioluminescent analysis of healthy females crossed with infected males showed that 50%, 62.5% and 37.5% of the female mice were subsequently positive for parasites in their ovaries, uteri and brain respectively. Although PCR confirmed the presence of parasites in the uterus of one of these mice, the blood of all mice was negative by PCR and LAMP. Subsequently, bioluminescent imaging of the offspring of infected female mice crossed with healthy males indicated parasites were present in the reproductive organs of both male (80%) and female (60%) offspring. These findings imply that transmission of T. b. gambiense 1135 occurs horizontally, most probably via sexual contact, and vertically in a murine model, which raises the possibility of a similar transmission in humans. This has wide reaching implications. Firstly, the observations made in this study are likely to be valid for wild animals acting as a reservoir for T. b. gambiense. Also, the reproductive organs may act as a refuge for parasites during drug treatment in a similar manner to the central nervous system. This could leave patients at risk of a relapse, ultimately allowing them to act as a reservoir for subsequent transmission by tsetse and possibly, horizontally and vertically. PMID:26735855

  19. A single amino acid substitution in the group 1 Trypanosoma brucei gambiense haptoglobin-hemoglobin receptor abolishes TLF-1 binding.

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    E DeJesus

    Full Text Available Critical to human innate immunity against African trypanosomes is a minor subclass of human high-density lipoproteins, termed Trypanosome Lytic Factor-1 (TLF-1. This primate-specific molecule binds to a haptoglobin-hemoglobin receptor (HpHbR on the surface of susceptible trypanosomes, initiating a lytic pathway. Group 1 Trypanosoma brucei gambiense causes human African Trypanosomiasis (HAT, escaping TLF-1 killing due to reduced uptake. Previously, we found that group 1 T. b. gambiense HpHbR (TbgHpHbR mRNA levels were greatly reduced and the gene contained substitutions within the open reading frame. Here we show that a single, highly conserved amino acid in the TbgHpHbR ablates high affinity TLF-1 binding and subsequent endocytosis, thus evading TLF-1 killing. In addition, we show that over-expression of TbgHpHbR failed to rescue TLF-1 susceptibility. These findings suggest that the single substitution present in the TbgHpHbR directly contributes to the reduced uptake and resistance to TLF-1 seen in these important human pathogens.

  20. A single amino acid substitution in the group 1 Trypanosoma brucei gambiense haptoglobin-hemoglobin receptor abolishes TLF-1 binding.

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    DeJesus, E; Kieft, R; Albright, B; Stephens, N A; Hajduk, S L

    2013-01-01

    Critical to human innate immunity against African trypanosomes is a minor subclass of human high-density lipoproteins, termed Trypanosome Lytic Factor-1 (TLF-1). This primate-specific molecule binds to a haptoglobin-hemoglobin receptor (HpHbR) on the surface of susceptible trypanosomes, initiating a lytic pathway. Group 1 Trypanosoma brucei gambiense causes human African Trypanosomiasis (HAT), escaping TLF-1 killing due to reduced uptake. Previously, we found that group 1 T. b. gambiense HpHbR (TbgHpHbR) mRNA levels were greatly reduced and the gene contained substitutions within the open reading frame. Here we show that a single, highly conserved amino acid in the TbgHpHbR ablates high affinity TLF-1 binding and subsequent endocytosis, thus evading TLF-1 killing. In addition, we show that over-expression of TbgHpHbR failed to rescue TLF-1 susceptibility. These findings suggest that the single substitution present in the TbgHpHbR directly contributes to the reduced uptake and resistance to TLF-1 seen in these important human pathogens. PMID:23637606

  1. [Serological evidence of the existence of a wild reservoir of Trypanosoma brucei gambiense in the Pendjari biosphere reservation in the Republic of Benin].

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    Guedegbe, B; Verhulst, A; Van Meirvenne, N; Pandey, V S; Doko, A

    1992-06-01

    In the national park of Pendjari, situated in the North-West of Benin, 91 wild animals, belonging to seven species, were darted. Thick and thin blood smears were examined for trypanosomes and plasma for trypanolytic antibodies against 6 antigenic variants of Trypanosoma brucei gambiense. Parasites were found in 13.92% and trypanolytic antibodies in 20.88% of the samples. A total of 28.57% of animals were positive by at least one of the two test systems used. Morphologically Trypanosoma congolense, T. vivax and T. brucei were identified. Overall prevalence was 40% in Adenota kob (n: 50), 13.63% in Alcelaphus buselaphus (n: 22), 10% in Hippotragus equinus (n: 10), 33% in Kobus defassa (n: 3), 0% in Phacochoerus aethiopicus (n: 3) and in Syncerus caffer (n: 2). The only lion (Panthera leo) examined was serologically positive. The results indicate that the wild animals are reservoirs of animal trypanosomes and suggest that among them Adenota kob and Panthera leo are carriers of T. brucei gambiense, one of the etiological aspects of human trypanosomiasis. PMID:1417158

  2. The miRNA and mRNA Signatures of Peripheral Blood Cells in Humans Infected with Trypanosoma brucei gambiense.

    Directory of Open Access Journals (Sweden)

    Smiths Lueong

    Full Text Available Simple, reliable tools for diagnosis of human African Trypanosomiases could ease field surveillance and enhance patient care. In particular, current methods to distinguish patients with (stage II and without (stage I brain involvement require samples of cerebrospinal fluid. We describe here an exploratory study to find out whether miRNAs from peripheral blood leukocytes might be useful in diagnosis of human trypanosomiasis, or for determining the stage of the disease. Using microarrays, we measured miRNAs in samples from Trypanosoma brucei gambiense-infected patients (9 stage I, 10 stage II, 8 seronegative parasite-negative controls and 12 seropositive, but parasite-negative subjects. 8 miRNAs (out of 1205 tested showed significantly lower expression in patients than in seronegative, parasite-negative controls, and 1 showed increased expression. There were no clear differences in miRNAs between patients in different disease stages. The miRNA profiles could not distinguish seropositive, but parasitologically negative samples from controls and results within this group did not correlate with those from the trypanolysis test. Some of the regulated miRNAs, or their predicted mRNA targets, were previously reported changed during other infectious diseases or cancer. We conclude that the changes in miRNA profiles of peripheral blood lymphocytes in human African trypanosomiasis are related to immune activation or inflammation, are probably disease-non-specific, and cannot be used to determine the disease stage. The approach has little promise for diagnostics but might yield information about disease pathology.

  3. Wild chimpanzees are infected by Trypanosoma brucei.

    Science.gov (United States)

    Jirků, Milan; Votýpka, Jan; Petrželková, Klára J; Jirků-Pomajbíková, Kateřina; Kriegová, Eva; Vodička, Roman; Lankester, Felix; Leendertz, Siv Aina J; Wittig, Roman M; Boesch, Christophe; Modrý, David; Ayala, Francisco J; Leendertz, Fabian H; Lukeš, Julius

    2015-12-01

    Although wild chimpanzees and other African great apes live in regions endemic for African sleeping sickness, very little is known about their trypanosome infections, mainly due to major difficulties in obtaining their blood samples. In present work, we established a diagnostic ITS1-based PCR assay that allows detection of the DNA of all four Trypanosoma brucei subspecies (Trypanosoma brucei brucei, Trypanosoma brucei rhodesiense, Trypanosoma brucei gambiense, and Trypanosoma brucei evansi) in feces of experimentally infected mice. Next, using this assay we revealed the presence of trypanosomes in the fecal samples of wild chimpanzees and this finding was further supported by results obtained using a set of primate tissue samples. Phylogenetic analysis of the ITS1 region showed that the majority of obtained sequences fell into the robust T. brucei group, providing strong evidence that these infections were caused by T. b. rhodesiense and/or T. b. gambiense. The optimized technique of trypanosome detection in feces will improve our knowledge about the epidemiology of trypanosomes in primates and possibly also other endangered mammals, from which blood and tissue samples cannot be obtained. Finally, we demonstrated that the mandrill serum was able to efficiently lyse T. b. brucei and T. b. rhodesiense, and to some extent T. b. gambiense, while the chimpanzee serum failed to lyse any of these subspecies. PMID:26110113

  4. Wild chimpanzees are infected by Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Milan Jirků

    2015-12-01

    Finally, we demonstrated that the mandrill serum was able to efficiently lyse T. b. brucei and T. b. rhodesiense, and to some extent T. b. gambiense, while the chimpanzee serum failed to lyse any of these subspecies.

  5. Estimates of the duration of the early and late stage of gambiense sleeping sickness

    OpenAIRE

    Chandramohan Daniel; Haydon Daniel T; Filipe João AN; Checchi Francesco; Chappuis François

    2008-01-01

    Abstract Background The durations of untreated stage 1 (early stage, haemo-lymphatic) and stage 2 (late stage, meningo-encephalitic) human African trypanosomiasis (sleeping sickness) due to Trypanosoma brucei gambiense are poorly quantified, but key to predicting the impact of screening on transmission. Here, we outline a method to estimate these parameters. Methods We first model the duration of stage 1 through survival analysis of untreated serological suspects detected during Médecins Sans...

  6. The isolation and partial characterization of the plasma membrane from Trypanosoma brucei.

    Science.gov (United States)

    Voorheis, H P; Gale, J S; Owen, M J; Edwards, W

    1979-04-15

    Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase. PMID:486094

  7. Role of expression site switching in the development of resistance to human Trypanosome Lytic Factor-1 in Trypanosoma brucei brucei.

    Science.gov (United States)

    Kieft, Rudo; Stephens, Natalie A; Capewell, Paul; MacLeod, Annette; Hajduk, Stephen L

    2012-05-01

    Human high-density lipoproteins (HDLs) play an important role in human innate immunity to infection by African trypanosomes with a minor subclass, Trypanosome Lytic Factor-1 (TLF-1), displaying highly selective cytotoxicity to the veterinary pathogen Trypanosoma brucei brucei but not against the human sleeping sickness pathogens Trypanosoma brucei gambiense or Trypanosoma brucei rhodesiense. T. b. rhodesiense has evolved the serum resistance associated protein (SRA) that binds and confers resistance to TLF-1 while T. b. gambiense lacks the gene for SRA indicating that these parasites have diverse mechanisms of resistance to TLF-1. Recently, we have shown that T. b. gambiense (group 1) resistance to TLF-1 correlated with the loss of the haptoglobin/hemoglobin receptor (HpHbR) expression, the protein responsible for high affinity binding and uptake of TLF-1. In the course of these studies we also examined TLF-1 resistant T. b. brucei cell lines, generated by long-term in vitro selection. We found that changes in TLF-1 susceptibility in T. b. brucei correlated with changes in variant surface glycoprotein (VSG) expression in addition to reduced TLF-1 binding and uptake. To determine whether the expressed VSG or expression site associated genes (ESAGs) contribute to TLF-1 resistance we prepared a TLF-1 resistant T. b. brucei with a selectable marker in a silent bloodstream expression site (BES). Drug treatment allowed rapid selection of trypanosomes that activated the tagged BES. These studies show that TLF-1 resistance in T. b. brucei is largely independent of the expressed VSG or ESAGs further supporting the central role of HpHbR expression in TLF-1 susceptibility in these cells. PMID:22226682

  8. Protective effect of humus extract against Trypanosoma brucei infection in mice.

    Science.gov (United States)

    Kodama, Hiroshi; Denso; Okazaki, Fumi; Ishida, Saeko

    2008-11-01

    Humic substances are formed during the decomposition of organic matter in humus, and are found in many natural environments in which organic materials and microorganisms are present. Oral administration of humus extract to mice successfully induced effective protection against experimental challenge by the two subspecies, Trypanosoma brucei brucei and T. brucei gambiense. Mortality was most reduced among mice who received a 3% humus extract for 21 days in drinking water ad libitum. Spleen cells from humus-administered mice exhibited significant non-specific cytotoxic activity against L1210 mouse leukemia target cells. Also, spleen cells produced significantly higher amounts of Interferon-gamma when stimulated in vitro with Concanavalin A than cells from normal controls. These results clearly show that administration to mice of humus extract induced effective resistance against Trypanosoma infection. Enhancement of the innate immune system may be involved in host defense against trypanosomiasis.

  9. Transport proteins determine drug sensitivity and resistance in a protozoan parasite, Trypanosoma brucei

    Science.gov (United States)

    Munday, Jane C.; Settimo, Luca; de Koning, Harry P.

    2015-01-01

    Drug resistance in pathogenic protozoa is very often caused by changes to the ‘transportome’ of the parasites. In Trypanosoma brucei, several transporters have been implicated in uptake of the main classes of drugs, diamidines and melaminophenyl arsenicals. The resistance mechanism had been thought to be due to loss of a transporter known to carry both types of agents: the aminopurine transporter P2, encoded by the gene TbAT1. However, although loss of P2 activity is well-documented as the cause of resistance to the veterinary diamidine diminazene aceturate (DA; Berenil®), cross-resistance between the human-use arsenical melarsoprol and the diamidine pentamidine (melarsoprol/pentamidine cross resistance, MPXR) is the result of loss of a separate high affinity pentamidine transporter (HAPT1). A genome-wide RNAi library screen for resistance to pentamidine, published in 2012, gave the key to the genetic identity of HAPT1 by linking the phenomenon to a locus that contains the closely related T. brucei aquaglyceroporin genes TbAQP2 and TbAQP3. Further analysis determined that knockdown of only one pore, TbAQP2, produced the MPXR phenotype. TbAQP2 is an unconventional aquaglyceroporin with unique residues in the “selectivity region” of the pore, and it was found that in several MPXR lab strains the WT gene was either absent or replaced by a chimeric protein, recombined with parts of TbAQP3. Importantly, wild-type AQP2 was also absent in field isolates of T. b. gambiense, correlating with the outcome of melarsoprol treatment. Expression of a wild-type copy of TbAQP2 in even the most resistant strain completely reversed MPXR and re-introduced HAPT1 function and transport kinetics. Expression of TbAQP2 in Leishmania mexicana introduced a pentamidine transport activity indistinguishable from HAPT1. Although TbAQP2 has been shown to function as a classical aquaglyceroporin it is now clear that it is also a high affinity drug transporter, HAPT1. We discuss here a

  10. Classical clinical signs in rats experimemtally infected with Trypanosoma brucei

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omolathebu

    2015-01-01

    Objective:To investigate clinical signs in Trypanosoma brucei infection in albino rats. Methods:Fourteen rats grouped into 2 with 7 rats in each group were used to determine classical clinical manifestation of Trypanosoma brucei infection in rats. Group A rats were uninfected control and Group B rats were infected with Trypanosoma brucei. Results:Parasitaemia was recorded in Group B by (3.86±0.34) d and the peak of parasitaemia was observed at Day 5 post infection. Classical signs observed included squint eyes, raised whiskers, lethargy, no weight loss, pyrexia, isolation from the other rats, and starry hair coat. Conclusions:These signs could be diagnostic or aid in diagnosis of Trypanosoma brucei infection in rats.

  11. Taxonomy Icon Data: Trypanosoma brucei [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Trypanosoma brucei Trypanosoma brucei Trypanosoma_brucei_L.png Trypanosoma_brucei_NL.png Trypanosoma_bruce...i_S.png Trypanosoma_brucei_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Trypanosoma+bruce...i&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=NL http://bioscie...ncedbc.jp/taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=S http://biosciencedbc.jp.../taxonomy_icon/icon.cgi?i=Trypanosoma+brucei&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=121 ...

  12. Accuracy of individual rapid tests for serodiagnosis of gambiense sleeping sickness in West Africa.

    Directory of Open Access Journals (Sweden)

    Vincent Jamonneau

    2015-02-01

    Full Text Available Individual rapid tests for serodiagnosis (RDT of human African trypanosomiasis (HAT are particularly suited for passive screening and surveillance. However, so far, no large scale evaluation of RDTs has been performed for diagnosis of Trypanosoma brucei gambiense HAT in West Africa. The objective of this study was to assess the diagnostic accuracy of 2 commercial HAT-RDTs on stored plasma samples from West Africa.SD Bioline HAT and HAT Sero-K-Set were performed on 722 plasma samples originating from Guinea and Côte d'Ivoire, including 231 parasitologically confirmed HAT patients, 257 healthy controls, and 234 unconfirmed individuals whose blood tested antibody positive in the card agglutination test but negative by parasitological tests. Immune trypanolysis was performed as a reference test for trypanosome specific antibody presence. Sensitivities in HAT patients were respectively 99.6% for SD Bioline HAT, and 99.1% for HAT Sero-K-Set, specificities in healthy controls were respectively 87.9% and 88.3%. Considering combined positivity in both RDTs, increased the specificity significantly (p ≤ 0.0003 to 93.4%, while 98.7% sensitivity was maintained. Specificities in controls were 98.7-99.6% for the combination of one or two RDTs with trypanolysis, maintaining a sensitivity of at least 98.1%.The observed specificity of the single RDTs was relatively low. Serial application of SD Bioline HAT and HAT Sero-K-Set might offer superior specificity compared to a single RDT, maintaining high sensitivity. The combination of one or two RDTs with trypanolysis seems promising for HAT surveillance.

  13. Trypanosoma brucei gambiense Spliced Leader RNA Is a More Specific Marker for Cure of Human African Trypanosomiasis Than T. b. gambiense DNA.

    Science.gov (United States)

    Ilboudo, Hamidou; Camara, Oumou; Ravel, Sophie; Bucheton, Bruno; Lejon, Veerle; Camara, Mamadou; Kaboré, Jacques; Jamonneau, Vincent; Deborggraeve, Stijn

    2015-12-15

    To assess the efficacy of treatment for human African trypanosomiasis, accurate tests that can discriminate relapse from cure are needed. We report the first data that the spliced leader (SL) RNA is a more specific marker for cure of human African trypanosomiasis than parasite DNA. In blood samples obtained from 61 patients in whom human African trypanosomiasis was cured, SL RNA detection had specificities of 98.4%-100%, while DNA detection had a specificity of only 77%. Data from our proof-of-concept study show that SL RNA detection has high potential as a test of cure.

  14. Syndromic algorithms for detection of gambiense human African trypanosomiasis in South Sudan.

    Directory of Open Access Journals (Sweden)

    Jennifer J Palmer

    Full Text Available BACKGROUND: Active screening by mobile teams is considered the best method for detecting human African trypanosomiasis (HAT caused by Trypanosoma brucei gambiense but the current funding context in many post-conflict countries limits this approach. As an alternative, non-specialist health care workers (HCWs in peripheral health facilities could be trained to identify potential cases who need testing based on their symptoms. We explored the predictive value of syndromic referral algorithms to identify symptomatic cases of HAT among a treatment-seeking population in Nimule, South Sudan. METHODOLOGY/PRINCIPAL FINDINGS: Symptom data from 462 patients (27 cases presenting for a HAT test via passive screening over a 7 month period were collected to construct and evaluate over 14,000 four item syndromic algorithms considered simple enough to be used by peripheral HCWs. For comparison, algorithms developed in other settings were also tested on our data, and a panel of expert HAT clinicians were asked to make referral decisions based on the symptom dataset. The best performing algorithms consisted of three core symptoms (sleep problems, neurological problems and weight loss, with or without a history of oedema, cervical adenopathy or proximity to livestock. They had a sensitivity of 88.9-92.6%, a negative predictive value of up to 98.8% and a positive predictive value in this context of 8.4-8.7%. In terms of sensitivity, these out-performed more complex algorithms identified in other studies, as well as the expert panel. The best-performing algorithm is predicted to identify about 9/10 treatment-seeking HAT cases, though only 1/10 patients referred would test positive. CONCLUSIONS/SIGNIFICANCE: In the absence of regular active screening, improving referrals of HAT patients through other means is essential. Systematic use of syndromic algorithms by peripheral HCWs has the potential to increase case detection and would increase their participation in HAT

  15. Mapping of VSG similarities in Trypanosoma brucei

    OpenAIRE

    Weirather, Jason L.; Wilson, Mary E; Donelson, John E.

    2011-01-01

    The protozoan parasite Trypanosoma brucei switches its variant surface glycoprotein (VSG) to subvert its mammalian hosts’ immune responses. The T. brucei genome contains as many as 1600 VSG genes (VSGs), but most are silent noncoding pseudogenes. Only one functional VSG, located in a telomere-linked expression site, is transcribed at a time. Silent VSGs are copied into a VSG expression site through gene conversion. Truncated gene conversion events can generate new mosaic VSGs with segments of...

  16. What happens when Trypanosoma brucei leaves Africa

    OpenAIRE

    Jensen, Robert E.; Simpson, Larry; Englund, Paul T.

    2008-01-01

    Julius Lukeš and co-workers evaluated the evolutionary origin of Trypanosoma equiperdum and Trypanosoma evansi, parasites that cause horse and camel diseases. Although similar to T. brucei, the sleeping-sickness parasite, these trypanosomes do not cycle through the tsetse fly and have been able to spread beyond Africa. Transmission occurs sexually, or via blood-sucking flies or vampire bats. They concluded that these parasites, which resemble yeast petite mutants, are T. brucei sub-species, w...

  17. Effects of tea on survival rates and liver pathology of Trypanosoma brucei brucei infected mice

    OpenAIRE

    Mbuthia, S.K; Wachira, N.W; Ngure, R.M; Ouma, J; Kagira, J. M.

    2011-01-01

    The current study investigated the effects of different types of Kenyan tea extracts on the pathogenesis ofTrypanosoma brucei brucei in a Swiss White mice model. Following infection with trypanosomes, the micewere monitored for survival and liver pathology. Tea significantly (P

  18. Anti-trypanosomal effect of Peristrophe bicalyculata extract on Trypanosoma brucei brucei-infected rats

    Institute of Scientific and Technical Information of China (English)

    Abdulazeez Mansurah Abimbola; Ibrahim Abdulrazak Baba; Edibo Zakari Yenusa; Sidali Joseph Omanibe; Idris Habeeb Oladimeji

    2013-01-01

    Objective: To investigate the in vitro and in vivo effect of whole plant extracts of Peristrophe bicalyculata on Trypanosoma brucei brucei-infected rats. Methods: The experiment was divided into two phases: In the first phase, the anti-trypanosomal activity of the hot water, cold water, methanol and butanol extracts of the whole plant were determined by incubating with Trypanosoma brucei brucei. The cold water extract was partially-purified and the anti-trypanosomal activity of the fractions determined. In the second phase, Trypanosoma brucei brucei-infected rats were treated with fraction 2c for nine days. Packed cell volume (PCV), high density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol (TC), triacylglycerol (TAG), aspartate aminotransferase, alanine aminotransferases (ALT), alkaline phosphatase (ALP), total and direct bilirubin levels were determined at the end of the experiment. Results:Cold water extract immobilized 90%of the parasites after 60 min of incubation, and fraction 2c completely immobilized the parasites after 35 min. It significantly increased PCV in Trypanosoma brucei brucei-infected rats. Decreased TC, TAG, HDL and LDL levels of infected rats increased significantly when rats were treated with the fraction, while elevated levels of total bilirubin and ALT also decreased. The difference in urea, direct bilirubin and ALP was not significant when infected rats were compared to rats in other groups. Conclusions:The ability of the plant to ameliorate the infection-induced biochemical changes calls for detailed investigation of the potentials of the plant for antitrypanosomiasis drug delivery.

  19. Involvement of lysosomes in the uptake of macromolecular material by bloodstream forms of Trypanosoma brucei.

    Science.gov (United States)

    Opperdoes, F R; Van Roy, J

    1982-09-01

    To investigate whether the lysosomes of Trypanosoma brucei are capable of uptake of macromolecules after internalization by the cell, we used Triton WR-1339, a non-digestible macromolecular compound, which is known to cause a marked decrease in the density of hepatic lysosomes due to massive intralysosomal storage. Intraperitoneal administration of 0.4 g/kg Triton WR-1339 to rats infected with T. brucei led to the development of a large vacuole in the trypanosomes between nucleus and kinetoplast within 22 h. Higher doses (2 g/kg) led to the disappearance of the trypanosomes from the blood and resulted in permanent cures (greater than 100 days). Lysosomes isolated from the trypanosomes of animals treated with a sub-curative dose showed a decrease in equilibrium density of 0.03 g/cm3 in sucrose gradients. These lysosomes were partly damaged as evidenced by a reduction in latency and an increase in the non-sedimentable part of lysosomal enzymes. We conclude that acid proteinase and alpha-mannosidase-containing organelles of T. brucei take up exogenous macromolecules and must therefore be considered as true lysosomes and that Triton WR-1339 acts in T. brucei as a true lysosomotropic drug. Its trypanocidal action probably results from an interference with lysosomal function.

  20. CHARACTERIZATION AND ANTIPARASITIC ACTIVITY OF BENZOPHENONE THIOSEMICARBAZONES ON Trypanosoma brucei brucei

    OpenAIRE

    Georges C. Accrombessi; Jacques Poupaert; Raymond H. Fatondji; Salomé D. S. Kpoviessi; Gbaguidi, Fernand A.; Bienvenu Glinma

    2011-01-01

    The structure of four synthesized thiosemicarbazones, substituted or not, of benzophenone has been confirmed by spectrometrical analysis IR, NMR 1H and 13C. Their anti-trypanosomal activities were evaluated on Trypanosoma brucei brucei. Among these compounds, benzophenone 4 phenyl-3-thiosemicarbazone 4 has the highest activity with the half-inhibitory concentration (IC50) = 8.48 micromolar (µM). Benzophenone 4-methyl-3-thiosemicarbazone 3 and benzophenone thiosemicarbazone 1 showed moderate a...

  1. Molecular variation of Trypanosoma brucei subspecies as revealed by AFLP fingerprinting

    OpenAIRE

    Agbo, E.E.C.; Majiwa, P.A.O.; Claassen, H.J.H.M.; Pas, te, M.F.W.

    2002-01-01

    Genetic analysis of Trypanosoma spp. depends on the detection of variation between strains. We have used the amplified fragment length polymorphism (AFLP) technique to develop a convenient and reliable method for genetic characterization of Trypanosome (sub)species. AFLP accesses multiple independent sites within the genome and would allow a better definition of the relatedness of different Trypanosome (sub)species. Nine isolates (3 from each T. brucei subspecies) were tested with 40 AFLP pri...

  2. Cell cycle regulation in Trypanosoma brucei

    OpenAIRE

    Tansy C Hammarton

    2007-01-01

    Cell division is regulated by intricate and interconnected signal transduction pathways that precisely coordinate, in time and space, the complex series of events involved in replicating and segregating the component parts of the cell. In Trypanosoma brucei, considerable progress has been made over recent years in identifying molecular regulators of the cell cycle and elucidating their functions, although many regulators undoubtedly remain to be identified, and there is still a long way to go...

  3. Motility modes of the parasite Trypanosoma brucei

    Science.gov (United States)

    Temel, Fatma Zeynep; Qu, Zijie; McAllaster, Michael; de Graffenried, Christopher; Breuer, Kenneth

    2015-11-01

    The parasitic single-celled protozoan Trypanosoma brucei causes African Sleeping Sickness, which is a fatal disease in humans and animals that threatens more than 60 million people in 36 African countries. Cell motility plays a critical role in the developmental phases and dissemination of the parasite. Unlike many other motile cells such as bacteria Escherichia coli or Caulobacter crescentus, the flagellum of T. brucei is attached along the length of its awl-like body, producing a unique mode of motility that is not fully understood or characterized. Here, we report on the motility of T. brucei, which swims using its single flagellum employing both rotating and undulating propulsion modes. We tracked cells in real-time in three dimensions using fluorescent microscopy. Data obtained from experiments using both short-term tracking within the field of view and long-term tracking using a tracking microscope were analyzed. Motility modes and swimming speed were analyzed as functions of cell size, rotation rate and undulation pattern. Research supported by NSF.

  4. Reduced Mitochondrial Membrane Potential Is a Late Adaptation of Trypanosoma brucei brucei to Isometamidium Preceded by Mutations in the γ Subunit of the F1Fo-ATPase

    Science.gov (United States)

    Munday, Jane C.; Tagoe, Daniel N. A.; Stelmanis, Valters; Schnaufer, Achim

    2016-01-01

    Background Isometamidium is the main prophylactic drug used to prevent the infection of livestock with trypanosomes that cause Animal African Trypanosomiasis. As well as the animal infective trypanosome species, livestock can also harbor the closely related human infective subspecies T. b. gambiense and T. b. rhodesiense. Resistance to isometamidium is a growing concern, as is cross-resistance to the diamidine drugs diminazene and pentamidine. Methodology/Principal Findings Two isometamidium resistant Trypanosoma brucei clones were generated (ISMR1 and ISMR15), being 7270- and 16,000-fold resistant to isometamidium, respectively, which retained their ability to grow in vitro and establish an infection in mice. Considerable cross-resistance was shown to ethidium bromide and diminazene, with minor cross-resistance to pentamidine. The mitochondrial membrane potentials of both resistant cell lines were significantly reduced compared to the wild type. The net uptake rate of isometamidium was reduced 2-3-fold but isometamidium efflux was similar in wild-type and resistant lines. Fluorescence microscopy and PCR analysis revealed that ISMR1 and ISMR15 had completely lost their kinetoplast DNA (kDNA) and both lines carried a mutation in the nuclearly encoded γ subunit gene of F1 ATPase, truncating the protein by 22 amino acids. The mutation compensated for the loss of the kinetoplast in bloodstream forms, allowing near-normal growth, and conferred considerable resistance to isometamidium and ethidium as well as significant resistance to diminazene and pentamidine, when expressed in wild type trypanosomes. Subsequent exposure to either isometamidium or ethidium led to rapid loss of kDNA and a further increase in isometamidium resistance. Conclusions/Significance Sub-lethal exposure to isometamidium gives rise to viable but highly resistant trypanosomes that, depending on sub-species, are infective to humans and cross-resistant to at least some diamidine drugs. The crucial

  5. Trypanosoma evansi is alike to Trypanosoma brucei brucei in the subcellular localisation of glycolytic enzymes

    Directory of Open Access Journals (Sweden)

    S Andrea Moreno

    2015-06-01

    Full Text Available Trypanosoma evansi, which causes surra, is descended from Trypanosoma brucei brucei, which causes nagana. Although both parasites are presumed to be metabolically similar, insufficient knowledge of T. evansi precludes a full comparison. Herein, we provide the first report on the subcellular localisation of the glycolytic enzymes in T. evansi, which is a alike to that of the bloodstream form (BSF of T. b. brucei: (i fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH, hexokinase, phosphofructokinase, glucose-6-phosphate isomerase, phosphoglycerate kinase, triosephosphate isomerase (glycolytic enzymes and glycerol-3-phosphate dehydrogenase (a glycolysis-auxiliary enzyme in glycosomes, (ii enolase, phosphoglycerate mutase, pyruvate kinase (glycolytic enzymes and a GAPDH isoenzyme in the cytosol, (iii malate dehydrogenase in cytosol and (iv glucose-6-phosphate dehydrogenase in both glycosomes and the cytosol. Specific enzymatic activities also suggest that T. evansi is alike to the BSF of T. b. brucei in glycolytic flux, which is much faster than the pentose phosphate pathway flux, and in the involvement of cytosolic GAPDH in the NAD+/NADH balance. These similarities were expected based on the close phylogenetic relationship of both parasites.

  6. Mapping of VSG similarities in Trypanosoma brucei.

    Science.gov (United States)

    Weirather, Jason L; Wilson, Mary E; Donelson, John E

    2012-02-01

    The protozoan parasite Trypanosoma brucei switches its variant surface glycoprotein (VSG) to subvert its mammalian hosts' immune responses. The T. brucei genome contains as many as 1600 VSG genes (VSGs), but most are silent noncoding pseudogenes. Only one functional VSG, located in a telomere-linked expression site, is transcribed at a time. Silent VSGs are copied into a VSG expression site through gene conversion. Truncated gene conversion events can generate new mosaic VSGs with segments of sequence identity to other VSGs. To examine the VSG family sub-structure within which these events occur, we combined the available VSG sequences and annotations with scripted BLAST searches to map the relationships among VSGs in the T. brucei genome. Clusters of related VSGs were visualized in 2- and 3-dimensions for different N- and C-terminal regions. Five types of N-termini (N1-N5) were observed, within which gene recombinational events are likely to occur, often with fully-coding 'functional' or 'atypical'VSGs centrally located between more dissimilar VSGs. Members of types N1, N3 and N4 are most closely related in the middle of the N-terminal region, whereas type N2 members are more similar near the N-terminus. Some preference occurs in pairing between specific N- and C-terminal types. Statistical analyses indicated no overall tendency for more related VSGs to be located closer in the genome than less related VSGs, although exceptions were noted. Many potential mosaic gene formation events within each N-terminal type were identified, contrasted by only one possible mosaic gene formation between N-terminal types (N1 and N2). These data suggest that mosaic gene formation is a major contributor to the overall VSG diversity, even though gene recombinational events between members of different N-terminal types occur only rarely. PMID:22079099

  7. Identifying Transmission Cycles at the Human-Animal Interface: The Role of Animal Reservoirs in Maintaining Gambiense Human African Trypanosomiasis

    OpenAIRE

    Sebastian Funk; Hiroshi Nishiura; Hans Heesterbeek; W. John Edmunds; Francesco Checchi

    2013-01-01

    Many infections can be transmitted between animals and humans. The epidemiological roles of different species can vary from important reservoirs to dead-end hosts. Here, we present a method to identify transmission cycles in different combinations of species from field data. We used this method to synthesise epidemiological and ecological data from Bipindi, Cameroon, a historical focus of gambiense Human African Trypanosomiasis (HAT, sleeping sickness), a disease that has often been considere...

  8. CHARACTERIZATION AND ANTIPARASITIC ACTIVITY OF BENZOPHENONE THIOSEMICARBAZONES ON Trypanosoma brucei brucei

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    Georges C. Accrombessi

    2011-02-01

    Full Text Available The structure of four synthesized thiosemicarbazones, substituted or not, of benzophenone has been confirmed by spectrometrical analysis IR, NMR 1H and 13C. Their anti-trypanosomal activities were evaluated on Trypanosoma brucei brucei. Among these compounds, benzophenone 4 phenyl-3-thiosemicarbazone 4 has the highest activity with the half-inhibitory concentration (IC50 = 8.48 micromolar (µM. Benzophenone 4-methyl-3-thiosemicarbazone 3 and benzophenone thiosemicarbazone 1 showed moderate anti-trypanosomal activity with IC50 values equal to 23.27 µM and 67.17 µM respectively. Benzophenone 2 methyl-3-thiosemicarbazone 2 showed no activity up to IC50 = 371.74 µM.

  9. Phenolic Constituents of Medicinal Plants with Activity against Trypanosoma brucei

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    Ya Nan Sun

    2016-04-01

    Full Text Available Neglected tropical diseases (NTDs affect over one billion people all over the world. These diseases are classified as neglected because they impact populations in areas with poor financial conditions and hence do not attract sufficient research investment. Human African Trypanosomiasis (HAT or sleeping sickness, caused by the parasite Trypanosoma brucei, is one of the NTDs. The current therapeutic interventions for T. brucei infections often have toxic side effects or require hospitalization so that they are not available in the rural environments where HAT occurs. Furthermore, parasite resistance is increasing, so that there is an urgent need to identify novel lead compounds against this infection. Recognizing the wide structural diversity of natural products, we desired to explore and identify novel antitrypanosomal chemotypes from a collection of natural products obtained from plants. In this study, 440 pure compounds from various medicinal plants were tested against T. brucei by in a screening using whole cell in vitro assays. As the result, twenty-two phenolic compounds exhibited potent activity against cultures of T. brucei. Among them, eight compounds—4, 7, 11, 14, 15, 18, 20, and 21—showed inhibitory activity against T. brucei, with IC50 values below 5 µM, ranging from 0.52 to 4.70 μM. Based on these results, we attempt to establish some general trends with respect to structure-activity relationships, which indicate that further investigation and optimization of these derivatives might enable the preparation of potentially useful compounds for treating HAT.

  10. Regulation and spatial organization of PCNA in Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Doris; Gassen, Alwine [University of Munich (LMU), Department Biology I, Genetics, Grosshaderner Str. 2-4, 82152 Martinsried (Germany); Maiser, Andreas; Leonhardt, Heinrich [University of Munich (LMU), Department Biology II, Grosshaderner Str. 2-4, 82152 Martinsried (Germany); Janzen, Christian J., E-mail: christian.janzen@uni-wuerzburg.de [University of Munich (LMU), Department Biology I, Genetics, Grosshaderner Str. 2-4, 82152 Martinsried (Germany)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer Characterization of the proliferating cell nuclear antigen in Trypanosoma brucei (TbPCNA). Black-Right-Pointing-Pointer TbPCNA is a suitable marker to detect replication in T. brucei. Black-Right-Pointing-Pointer TbPCNA distribution and regulation is different compared to closely related parasites T. cruzi and Leishmania donovani. -- Abstract: As in most eukaryotic cells, replication is regulated by a conserved group of proteins in the early-diverged parasite Trypanosoma brucei. Only a few components of the replication machinery have been described in this parasite and regulation, sub-nuclear localization and timing of replication are not well understood. We characterized the proliferating cell nuclear antigen in T. brucei (TbPCNA) to establish a spatial and temporal marker for replication. Interestingly, PCNA distribution and regulation is different compared to the closely related parasites Trypanosoma cruzi and Leishmania donovani. TbPCNA foci are clearly detectable during S phase of the cell cycle but in contrast to T. cruzi they are not preferentially located at the nuclear periphery. Furthermore, PCNA seems to be degraded when cells enter G2 phase in T. brucei suggesting different modes of replication regulation or functions of PCNA in these closely related eukaryotes.

  11. A comparative study on the susceptibility of male and female albino mice to Trypanosoma brucei brucei

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    A.A. Turay, G.O. Nwobu, G.R.A. Okogun, C.U. Igwe, K. Adeyeye, K.E. Aghatise, H.O. Okpal & Y.M. Tatfeng

    2005-03-01

    Full Text Available Background & objectives: Trypanosomiasis has remained a major set-back in the development oflivestock farming in tropical Africa. Thus the need for ascertaining the trypanotolerant levels ofdomestic animal breeds and possible improvement on them cannot be over-emphasised.Methods: Level of trypanotolerance in animals was compared between sexes using albino mice infectedwith a Nigerian strain of Trypanosoma brucei brucei at a 50% mouse lethal dose (MLD50.Results: The male mice showed unrestrained parasite growth with a prepatent period (PP of two daysand a mean survival period (MSP of six days corresponding to a gradual decrease in packed cellvolume (PCV, body weight, diet response and white blood cells (WBC count to the time of death.Their female counterparts showed a PP of three days and MSP of ten days with a similar PCV gradientbut a refractory WBC count. There was no significant difference in the differential leucocytes countin both sexes. However, the eosinophils count was significantly higher in the infected animals. It wasfound that female albino mice exercised more parasite restraint than their male counterparts.Interpretation & conclusion: The result suggests that the female animals may be more trypanotoleranthence may be more useful in protein production in trypanosomiasis endemic areas. However, furtherresearch using large domestic breeds like goats and sheep may be required to confirm the hypothesis.

  12. Evaluation of In Vitro Activity of Essential Oils against Trypanosoma brucei brucei and Trypanosoma evansi

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    Nathan Habila

    2010-01-01

    Full Text Available Essential oils (EOs from Cymbopogon citratus (CC, Eucalyptus citriodora (EC, Eucalyptus camaldulensis (ED, and Citrus sinensis (CS were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity against Trypanosoma brucei brucei (Tbb and Trypanosoma evansi (T. evansi. The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb and T. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09% in CS, 6-octenal (77.11% in EC, Eucalyptol (75% in ED, and Citral (38.32% in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy.

  13. Evaluation of In Vitro Activity of Essential Oils against Trypanosoma brucei brucei and Trypanosoma evansi.

    Science.gov (United States)

    Habila, Nathan; Agbaji, Abel S; Ladan, Zakari; Bello, Isaac A; Haruna, Emmanuel; Dakare, Monday A; Atolagbe, Taofiq O

    2010-01-01

    Essential oils (EOs) from Cymbopogon citratus (CC), Eucalyptus citriodora (EC), Eucalyptus camaldulensis (ED), and Citrus sinensis (CS) were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity against Trypanosoma brucei brucei (Tbb) and Trypanosoma evansi (T. evansi). The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb and T. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09%) in CS, 6-octenal (77.11%) in EC, Eucalyptol (75%) in ED, and Citral (38.32%) in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy. PMID:20700425

  14. Evaluation of In Vitro Activity of Essential Oils against Trypanosoma brucei brucei and Trypanosoma evansi

    Science.gov (United States)

    Habila, Nathan; Agbaji, Abel S.; Ladan, Zakari; Bello, Isaac A.; Haruna, Emmanuel; Dakare, Monday A.; Atolagbe, Taofiq O.

    2010-01-01

    Essential oils (EOs) from Cymbopogon citratus (CC), Eucalyptus citriodora (EC), Eucalyptus camaldulensis (ED), and Citrus sinensis (CS) were obtained by hydrodistillation process. The EOs were evaluated in vitro for activity against Trypanosoma brucei brucei (Tbb) and Trypanosoma evansi (T. evansi). The EOs were found to possess antitrypanosomal activity in vitro in a dose-dependent pattern in a short period of time. The drop in number of parasite over time was achieved doses of 0.4 g/ml, 0.2 g/mL, and 0.1 g/mL for all the EOs. The concentration of 0.4 g/mL CC was more potent at 3 minutes and 2 minutes for Tbb and T. evansi, respectively. The GC-MS analysis of the EOs revealed presence of Cyclobutane (96.09%) in CS, 6-octenal (77.11%) in EC, Eucalyptol (75%) in ED, and Citral (38.32%) in CC among several other organic compounds. The results are discussed in relation to trypanosome chemotherapy. PMID:20700425

  15. Triacylglycerol Storage in Lipid Droplets in Procyclic Trypanosoma brucei.

    Science.gov (United States)

    Allmann, Stefan; Mazet, Muriel; Ziebart, Nicole; Bouyssou, Guillaume; Fouillen, Laetitia; Dupuy, Jean-William; Bonneu, Marc; Moreau, Patrick; Bringaud, Frédéric; Boshart, Michael

    2014-01-01

    Carbon storage is likely to enable adaptation of trypanosomes to nutritional challenges or bottlenecks during their stage development and migration in the tsetse. Lipid droplets are candidates for this function. This report shows that feeding of T. brucei with oleate results in a 4-5 fold increase in the number of lipid droplets, as quantified by confocal fluorescence microscopy and by flow cytometry of BODIPY 493/503-stained cells. The triacylglycerol (TAG) content also increased 4-5 fold, and labeled oleate is incorporated into TAG. Fatty acid carbon can thus be stored as TAG in lipid droplets under physiological growth conditions in procyclic T. brucei. β-oxidation has been suggested as a possible catabolic pathway for lipids in T. brucei. A single candidate gene, TFEα1 with coding capacity for a subunit of the trifunctional enzyme complex was identified. TFEα1 is expressed in procyclic T. brucei and present in glycosomal proteomes, Unexpectedly, a TFEα1 gene knock-out mutant still expressed wild-type levels of previously reported NADP-dependent 3-hydroxyacyl-CoA dehydrogenase activity, and therefore, another gene encodes this enzymatic activity. Homozygous Δtfeα1/Δtfeα1 null mutant cells show a normal growth rate and an unchanged glycosomal proteome in procyclic T. brucei. The decay kinetics of accumulated lipid droplets upon oleate withdrawal can be fully accounted for by the dilution effect of cell division in wild-type and Δtfeα1/Δtfeα1 cells. The absence of net catabolism of stored TAG in procyclic T. brucei, even under strictly glucose-free conditions, does not formally exclude a flux through TAG, in which biosynthesis equals catabolism. Also, the possibility remains that TAG catabolism is completely repressed by other carbon sources in culture media or developmentally activated in post-procyclic stages in the tsetse. PMID:25493940

  16. Triacylglycerol Storage in Lipid Droplets in Procyclic Trypanosoma brucei.

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    Stefan Allmann

    Full Text Available Carbon storage is likely to enable adaptation of trypanosomes to nutritional challenges or bottlenecks during their stage development and migration in the tsetse. Lipid droplets are candidates for this function. This report shows that feeding of T. brucei with oleate results in a 4-5 fold increase in the number of lipid droplets, as quantified by confocal fluorescence microscopy and by flow cytometry of BODIPY 493/503-stained cells. The triacylglycerol (TAG content also increased 4-5 fold, and labeled oleate is incorporated into TAG. Fatty acid carbon can thus be stored as TAG in lipid droplets under physiological growth conditions in procyclic T. brucei. β-oxidation has been suggested as a possible catabolic pathway for lipids in T. brucei. A single candidate gene, TFEα1 with coding capacity for a subunit of the trifunctional enzyme complex was identified. TFEα1 is expressed in procyclic T. brucei and present in glycosomal proteomes, Unexpectedly, a TFEα1 gene knock-out mutant still expressed wild-type levels of previously reported NADP-dependent 3-hydroxyacyl-CoA dehydrogenase activity, and therefore, another gene encodes this enzymatic activity. Homozygous Δtfeα1/Δtfeα1 null mutant cells show a normal growth rate and an unchanged glycosomal proteome in procyclic T. brucei. The decay kinetics of accumulated lipid droplets upon oleate withdrawal can be fully accounted for by the dilution effect of cell division in wild-type and Δtfeα1/Δtfeα1 cells. The absence of net catabolism of stored TAG in procyclic T. brucei, even under strictly glucose-free conditions, does not formally exclude a flux through TAG, in which biosynthesis equals catabolism. Also, the possibility remains that TAG catabolism is completely repressed by other carbon sources in culture media or developmentally activated in post-procyclic stages in the tsetse.

  17. KREX2 is not essential for either procyclic or bloodstream form Trypanosoma brucei.

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    Jason Carnes

    Full Text Available BACKGROUND: Most mitochondrial mRNAs in Trypanosoma brucei require RNA editing for maturation and translation. The edited RNAs primarily encode proteins of the oxidative phosphorylation system. These parasites undergo extensive changes in energy metabolism between the insect and bloodstream stages which are mirrored by alterations in RNA editing. Two U-specific exonucleases, KREX1 and KREX2, are both present in protein complexes (editosomes that catalyze RNA editing but the relative roles of each protein are not known. METHODOLOGY/PRINCIPAL FINDINGS: The requirement for KREX2 for RNA editing in vivo was assessed in both procyclic (insect and bloodstream form parasites by methods that use homologous recombination for gene elimination. These studies resulted in null mutant cells in which both alleles were eliminated. The viability of these cells demonstrates that KREX2 is not essential in either life cycle stage, despite certain defects in RNA editing in vivo. Furthermore, editosomes isolated from KREX2 null cells require KREX1 for in vitro U-specific exonuclease activity. CONCLUSIONS: KREX2 is a U-specific exonuclease that is dispensable for RNA editing in vivo in T. brucei BFs and PFs. This result suggests that the U deletion activity, which is required for RNA editing, is primarily mediated in vivo by KREX1 which is normally found associated with only one type of editosome. The retention of the KREX2 gene implies a non-essential role or a role that is essential in other life cycle stages or conditions.

  18. Testicular pathology, gonadal and epididymal sperm reserves of Yankasa rams infected with experimental Trypanosoma brucei brucei and Trypanosoma evansi

    Science.gov (United States)

    Wada, Yunusa A.; Oniye, Sonnie J.; Rekwot, Peter I.; Okubanjo, Oluyinka O.

    2016-01-01

    Aim: The study was conducted to evaluate the pathological effects of trypanosomosis on the testes, gonadal, and epididymal sperm reserves of Yankasa rams for 98 days. Materials and Methods: A total of 16 Yankasa rams, aged between 24 and 30 months and weighed between 22 and 25 kg, were acclimatized for a period of 2-months in a clean fly proof house and were adequately fed and given water ad-libitum. Of the 16 rams, 12 that were clinically fit for the experiment at the end of the acclimatization period were randomly divided into four groups: Groups I, II, III, and IV, each having 3 rams. Groups I and II were each challenged singly with experimental Trypanosoma brucei brucei (Federer strain) and Trypanosoma evansi (Sokoto strain), respectively, while Group III was challenged with mixed T. brucei brucei and T. evansi parasites (50% of each species in the infective inoculum) and Group IV was left as an uninfected control. Each infected ram received 2 mL of the infected blood containing 2×106 trypomastigotes via the jugular vein, while the control group received 2 mL each, normal saline. Results: All the infected rams developed clinical signs typical of trypanosomosis at varying pre-patent periods. The gross lesions observed in the infected rams in Group II were moderate and more severe in those of Groups I and III. Histological sections of the testes of infected rams (Groups I, II, and III) showed moderate (T. evansi-infected group) to severe (mixed and T. brucei brucei-infected groups) testicular degenerations with reduction in number of spermatogenic cell layers, degenerated seminiferous tubules, congested interlobular spaces, loss of tissue architecture with significant (p<0.01) depletion, and loss of gonadal and epididymal sperm reserves in Groups I and III in comparison to Group II and the control Group IV. No observable clinical signs and histopathological lesions were found in those rams of the control Group IV. Conclusion: The study concluded that

  19. Testicular pathology, gonadal and epididymal sperm reserves of Yankasa rams infected with experimental Trypanosoma brucei brucei and Trypanosoma evansi

    Directory of Open Access Journals (Sweden)

    Yunusa A. Wada

    2016-07-01

    Full Text Available Aim: The study was conducted to evaluate the pathological effects of trypanosomosis on the testes, gonadal, and epididymal sperm reserves of Yankasa rams for 98 days. Materials and Methods: A total of 16 Yankasa rams, aged between 24 and 30 months and weighed between 22 and 25 kg, were acclimatized for a period of 2-months in a clean fly proof house and were adequately fed and given water ad-libitum. Of the 16 rams, 12 that were clinically fit for the experiment at the end of the acclimatization period were randomly divided into four groups: Groups I, II, III, and IV, each having 3 rams. Groups I and II were each challenged singly with experimental Trypanosoma brucei brucei (Federer strain and Trypanosoma evansi (Sokoto strain, respectively, while Group III was challenged with mixed T. brucei brucei and T. evansi parasites (50% of each species in the infective inoculum and Group IV was left as an uninfected control. Each infected ram received 2 mL of the infected blood containing 2×106 trypomastigotes via the jugular vein, while the control group received 2 mL each, normal saline. Results: All the infected rams developed clinical signs typical of trypanosomosis at varying pre-patent periods. The gross lesions observed in the infected rams in Group II were moderate and more severe in those of Groups I and III. Histological sections of the testes of infected rams (Groups I, II, and III showed moderate (T. evansi-infected group to severe (mixed and T. brucei brucei-infected groups testicular degenerations with reduction in number of spermatogenic cell layers, degenerated seminiferous tubules, congested interlobular spaces, loss of tissue architecture with significant (p<0.01 depletion, and loss of gonadal and epididymal sperm reserves in Groups I and III in comparison to Group II and the control Group IV. No observable clinical signs and histopathological lesions were found in those rams of the control Group IV. Conclusion: The study concluded

  20. Nanomolar Inhibitors of Trypanosoma brucei RNA Triphosphatase

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    Paul Smith

    2016-02-01

    Full Text Available Eukaryal taxa differ with respect to the structure and mechanism of the RNA triphosphatase (RTPase component of the mRNA capping apparatus. Protozoa, fungi, and certain DNA viruses have a metal-dependent RTPase that belongs to the triphosphate tunnel metalloenzyme (TTM superfamily. Because the structures, active sites, and chemical mechanisms of the TTM-type RTPases differ from those of mammalian RTPases, the TTM RTPases are potential targets for antiprotozoal, antifungal, and antiviral drug discovery. Here, we employed RNA interference (RNAi knockdown methods to show that Trypanosoma brucei RTPase Cet1 (TbCet1 is necessary for proliferation of procyclic cells in culture. We then conducted a high-throughput biochemical screen for small-molecule inhibitors of the phosphohydrolase activity of TbCet1. We identified several classes of chemicals—including chlorogenic acids, phenolic glycopyranosides, flavonoids, and other phenolics—that inhibit TbCet1 with nanomolar to low-micromolar 50% inhibitory concentrations (IC50s. We confirmed the activity of these compounds, and tested various analogs thereof, by direct manual assays of TbCet1 phosphohydrolase activity. The most potent nanomolar inhibitors included tetracaffeoylquinic acid, 5-galloylgalloylquinic acid, pentagalloylglucose, rosmarinic acid, and miquelianin. TbCet1 inhibitors were less active (or inactive against the orthologous TTM-type RTPases of mimivirus, baculovirus, and budding yeast (Saccharomyces cerevisiae. Our results affirm that a TTM RTPase is subject to potent inhibition by small molecules, with the caveat that parallel screens against TTM RTPases from multiple different pathogens may be required to fully probe the chemical space of TTM inhibition.

  1. Monitoring the use of nifurtimox-eflornithine combination therapy (NECT in the treatment of second stage gambiense human African trypanosomiasis

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    Franco JR

    2012-08-01

    Full Text Available Jose R Franco,1 Pere P Simarro,1 Abdoulaye Diarra,2 Jose A Ruiz-Postigo,3 Mireille Samo,1 Jean G Jannin11World Health Organization, Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, Geneva, Switzerland; 2World Health Organization, Regional Office for Africa, Brazzaville, Congo; 3World Health Organization, Communicable Disease Control, Control of Tropical Diseases and Zoonoses Regional Office for the Eastern Mediterranean, Cairo, EgyptAbstract: After inclusion of the nifurtimox-eflornithine combination therapy (NECT in the Model List of Essential Medicines for the treatment of second-stage gambiense human African trypanosomiasis (HAT, the World Health Organization, in collaboration with National Sleeping Sickness Control Programs and nongovernmental organizations set up a pharmacovigilance system to assess the safety and efficacy of NECT during its routine use. Data were collected for 1735 patients treated with NECT in nine disease endemic countries during 2010–2011. At least one adverse event (AE was described in 1043 patients (60.1% and a total of 3060 AE were reported. Serious adverse events (SAE were reported for 19 patients (1.1% of treated, leading to nine deaths (case fatality rate of 0.5%. The most frequent AE were gastrointestinal disorders (vomiting/nausea and abdominal pain, followed by headache, musculoskeletal pains, and vertigo. The most frequent SAE and cause of death were convulsions, fever, and coma that were considered as reactive encephalopathy. Two hundred and sixty-two children below 15 years old were treated. The characteristics of AE were similar to adults, but the major AE were less frequent in children with only one SAE and no deaths registered in this group. Gastrointestinal problems (vomiting and abdominal pain were more frequent than in adults, but musculoskeletal pains, vertigo, asthenia, neuropsychiatric troubles (headaches, seizures, tremors, hallucinations, insomnia were less

  2. Pentatricopeptide repeat proteins in Trypanosoma brucei function in mitochondrial ribosomes

    OpenAIRE

    Pusnik, Mascha; Small, Ian; Read, Laurie K.; Fabbro, Thomas; Schneider, André

    2008-01-01

    The pentatricopeptide repeat (PPR), a degenerate 35-amino-acid motif, defines a novel eukaryotic protein family. Plants have 400 to 500 distinct PPR proteins, whereas other eukaryotes generally have fewer than 5. The few PPR proteins that have been studied have roles in organellar gene expression, probably via direct interaction with RNA. Here we show that the parasitic protozoan Trypanosoma brucei encodes 28 distinct PPR proteins, an extraordinarily high number for a nonplant organism. A com...

  3. Trypanosoma brucei mitochondrial respiratome: Composition and organization in procyclic form

    KAUST Repository

    Acestor, Nathalie

    2011-05-24

    The mitochondrial respiratory chain is comprised of four different protein complexes (I-IV), which are responsible for electron transport and generation of proton gradient in the mitochondrial intermembrane space. This proton gradient is then used by F oF 1-ATP synthase (complex V) to produce ATP by oxidative phosphorylation. In this study, the respiratory complexes I, II, and III were affinity purified from Trypanosoma brucei procyclic form cells and their composition was determined by mass spectrometry. The results along with those that we previously reported for complexes IV and V showed that the respiratome of Trypanosoma is divergent because many of its proteins are unique to this group of organisms. The studies also identified two mitochondrial subunit proteins of respiratory complex IV that are encoded by edited RNAs. Proteomics data from analyses of complexes purified using numerous tagged component proteins in each of the five complexes were used to generate the first predicted protein-protein interaction network of the Trypanosoma brucei respiratory chain. These results provide the first comprehensive insight into the unique composition of the respiratory complexes in Trypanosoma brucei, an early diverged eukaryotic pathogen. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Comparative genomics of drug resistance in Trypanosoma brucei rhodesiense.

    Science.gov (United States)

    Graf, Fabrice E; Ludin, Philipp; Arquint, Christian; Schmidt, Remo S; Schaub, Nadia; Kunz Renggli, Christina; Munday, Jane C; Krezdorn, Jessica; Baker, Nicola; Horn, David; Balmer, Oliver; Caccone, Adalgisa; de Koning, Harry P; Mäser, Pascal

    2016-09-01

    Trypanosoma brucei rhodesiense is one of the causative agents of human sleeping sickness, a fatal disease that is transmitted by tsetse flies and restricted to Sub-Saharan Africa. Here we investigate two independent lines of T. b. rhodesiense that have been selected with the drugs melarsoprol and pentamidine over the course of 2 years, until they exhibited stable cross-resistance to an unprecedented degree. We apply comparative genomics and transcriptomics to identify the underlying mutations. Only few mutations have become fixed during selection. Three genes were affected by mutations in both lines: the aminopurine transporter AT1, the aquaporin AQP2, and the RNA-binding protein UBP1. The melarsoprol-selected line carried a large deletion including the adenosine transporter gene AT1, whereas the pentamidine-selected line carried a heterozygous point mutation in AT1, G430R, which rendered the transporter non-functional. Both resistant lines had lost AQP2, and both lines carried the same point mutation, R131L, in the RNA-binding motif of UBP1. The finding that concomitant deletion of the known resistance genes AT1 and AQP2 in T. b. brucei failed to phenocopy the high levels of resistance of the T. b. rhodesiense mutants indicated a possible role of UBP1 in melarsoprol-pentamidine cross-resistance. However, homozygous in situ expression of UBP1-Leu(131) in T. b. brucei did not affect the sensitivity to melarsoprol or pentamidine. PMID:26973180

  5. Changes in blood sugar levels of rats experimentally infected with Trypanosoma brucei and treated with imidocarb dipropionate and diminazene aceturate

    OpenAIRE

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omalathebu

    2016-01-01

    Objective: To determine the effect of Trypanosoma brucei (T. brucei) on blood sugar level of infected rats. Methods: The experiment was done with 42 albino rats grouped into 3 groups of 14 members each. Group A was uninfected (control group), Group B was infected with T. brucei and treated with diminazene aceturate, and Group C was infected with T. brucei and treated with imidocarb dipropionate. Blood samples were collected from the media canthus of the experimental rats on ...

  6. Secondary Metabolites from Vietnamese Marine Invertebrates with Activity against Trypanosoma brucei and T. cruzi

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    Nguyen Phuong Thao

    2014-06-01

    Full Text Available Marine-derived natural products from invertebrates comprise an extremely diverse and promising source of the compounds from a wide variety of structural classes. This study describes the discovery of five marine natural products with activity against Trypanosoma species by natural product library screening using whole cell in vitro assays. We investigated the anti-trypanosomal activity of the extracts from the soft corals and echinoderms living in Vietnamese seas. Of the samples screened, the methanolic extracts of several marine organisms exhibited potent activities against cultures of Trypanosoma brucei and T. cruzi (EC50 < 5.0 μg/mL. Among the compounds isolated from these extracts, laevigatol B (1 from Lobophytum crassum and L. laevigatum, (24S-ergost-4-ene-3-one (2 from Sinularia dissecta, astropectenol A (3 from Astropecten polyacanthus, and cholest-8-ene-3β,5α,6β,7α-tetraol (4 from Diadema savignyi showed inhibitory activity against T. brucei with EC50 values ranging from 1.57 ± 0.14 to 14.6 ± 1.36 μM, relative to the positive control, pentamidine (EC50 = 0.015 ± 0.003 μM. Laevigatol B (1 and 5α-cholest-8(14-ene-3β,7α-diol (5 exhibited also significant inhibitory effects on T. cruzi. The cytotoxic activity of the pure compounds on mammalian cells was also assessed and found to be insignificant in all cases. This is the first report on the inhibitory effects of marine organisms collected in Vietnamese seas against Trypanosoma species responsible for neglected tropical diseases.

  7. Rab23 is a flagellar protein in Trypanosoma brucei

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    Field Mark C

    2011-06-01

    Full Text Available Abstract Background Rab small GTPases are important mediators of membrane transport, and orthologues frequently retain similar locations and functions, even between highly divergent taxa. In metazoan organisms Rab23 is an important negative regulator of Sonic hedgehog signaling and is crucial for correct development and differentiation of cellular lineages by virtue of an involvement in ciliary recycling. Previously, we reported that Trypanosoma brucei Rab23 localized to the nuclear envelope 1, which is clearly inconsistent with the mammalian location and function. As T. brucei is unicellular the potential that Rab23 has no role in cell signaling was possible. Here we sought to further investigate the role(s of Rab23 in T. brucei to determine if Rab23 was an example of a Rab protein with divergent function in distinct taxa. Methods/major findings The taxonomic distribution of Rab23 was examined and compared with the presence of flagella/cilia in representative taxa. Despite evidence for considerable secondary loss, we found a clear correlation between a conventional flagellar structure and the presence of a Rab23 orthologue in the genome. By epitope-tagging, Rab23 was localized and found to be present at the flagellum throughout the cell cycle. However, RNAi knockdown did not result in a flagellar defect, suggesting that Rab23 is not required for construction or maintenance of the flagellum. Conclusions The location of Rab23 at the flagellum is conserved between mammals and trypanosomes and the Rab23 gene is restricted to flagellated organisms. These data may suggest the presence of a Rab23-mediated signaling mechanism in trypanosomes.

  8. T cells and macrophages in Trypanosoma brucei-related glomerulopathy.

    Science.gov (United States)

    van Velthuysen, M L; Mayen, A E; van Rooijen, N; Fleuren, G J; de Heer, E; Bruijn, J A

    1994-08-01

    In a previous study, susceptibility for Trypanosoma brucei-related glomerulopathy in mice was shown to be dependent on non-major histocompatibility complex genes. Glomerular disease in this model could not be explained by the production of autoantibodies alone. In order to analyze which part of the defense system, in addition to the B-cell compartment, is involved in the development of this infection-related glomerular disease, groups of athymic (BALB/c rnu/rnu), splenectomized, or macrophage-depleted BALB/c mice were inoculated with T. brucei parasites. Polyclonal B-cell activation, invariably observed in infected BALB/c mice, was absent in BALB/c rnu/rnu mice. Glomerular disease in athymic mice, however, as defined by albuminuria and deposition of immune complexes, was not different from that seen in euthymic infected BALB/c mice. Splenectomy prior to inoculation of parasites led to a decreased incidence of albuminuria in 40% of the animals, whereas splenectomy 21 days after inoculation reduced albuminuria significantly, suggesting a role for spleen cells in the induction of glomerular disease. After macrophage depletion with liposome-encapsulated dichlorodimethylene-diphosphonate, infected BALB/c mice developed significantly higher albuminuria levels for a period up to 2 weeks after depletion. Therefore, it was concluded that the development of T. brucei-related glomerular disease is independent of thymus-matured T cells, while the involvement of macrophages in the development of proteinuria is inhibitory rather than disease inducing. Spleen cells other than thymus-dependent T cells, B cells, and macrophages should be investigated for their role in the pathogenesis of this glomerulopathy. PMID:7913696

  9. VSG gene expression site control in insect form Trypanosoma brucei.

    OpenAIRE

    Rudenko, G; Blundell, P A; Taylor, M. C.; Kieft, R.; Borst, P

    1994-01-01

    When the African trypanosome Trypanosoma brucei is taken up from mammals by a tse-tse fly, it replaces its variant surface glycoprotein (VSG) coat by a procyclin coat. Transcription of VSG genes stops in the fly, but transcription of sequences derived from the promoter area of the VSG expression site(s) remains high. Whether this is due to continuing high activity of one promoter or to low activity of many promoters was unclear. We have used the small differences between the sequences of diff...

  10. Minimum Information Loss Based Multi-kernel Learning for Flagellar Protein Recognition in Trypanosoma Brucei

    KAUST Repository

    Wang, Jingyan

    2014-12-01

    Trypanosma brucei (T. Brucei) is an important pathogen agent of African trypanosomiasis. The flagellum is an essential and multifunctional organelle of T. Brucei, thus it is very important to recognize the flagellar proteins from T. Brucei proteins for the purposes of both biological research and drug design. In this paper, we investigate computationally recognizing flagellar proteins in T. Brucei by pattern recognition methods. It is argued that an optimal decision function can be obtained as the difference of probability functions of flagella protein and the non-flagellar protein for the purpose of flagella protein recognition. We propose to learn a multi-kernel classification function to approximate this optimal decision function, by minimizing the information loss of such approximation which is measured by the Kull back-Leibler (KL) divergence. An iterative multi-kernel classifier learning algorithm is developed to minimize the KL divergence for the problem of T. Brucei flagella protein recognition, experiments show its advantage over other T. Brucei flagellar protein recognition and multi-kernel learning methods. © 2014 IEEE.

  11. Effects of DMSO on Diminazene Efficacy in Experimental Murine T. brucei Infection

    OpenAIRE

    K.I. Eghianruwa; Anika, S.M.

    2012-01-01

    This study evaluated the influence of dimethyl sulfoxide (DMSO) daily supplementation on diminazene treatment of trypanosomosis. Four groups of Trypanosoma brucei brucei infected rats received 7.0 mg/kg diminazene aceturate on day 7 post infection. Three of the four groups received different doses of DMSO (0.5, 1.0 and 2.0 g/kg, respectively) in addition to diminazene treatment. The changes in hematological parameters and the weights of liver, spleen and heart caused by T. brucei infection we...

  12. Telomeric expression sites are highly conserved in Trypanosoma brucei.

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    Christiane Hertz-Fowler

    Full Text Available Subtelomeric regions are often under-represented in genome sequences of eukaryotes. One of the best known examples of the use of telomere proximity for adaptive purposes are the bloodstream expression sites (BESs of the African trypanosome Trypanosoma brucei. To enhance our understanding of BES structure and function in host adaptation and immune evasion, the BES repertoire from the Lister 427 strain of T. brucei were independently tagged and sequenced. BESs are polymorphic in size and structure but reveal a surprisingly conserved architecture in the context of extensive recombination. Very small BESs do exist and many functioning BESs do not contain the full complement of expression site associated genes (ESAGs. The consequences of duplicated or missing ESAGs, including ESAG9, a newly named ESAG12, and additional variant surface glycoprotein genes (VSGs were evaluated by functional assays after BESs were tagged with a drug-resistance gene. Phylogenetic analysis of constituent ESAG families suggests that BESs are sequence mosaics and that extensive recombination has shaped the evolution of the BES repertoire. This work opens important perspectives in understanding the molecular mechanisms of antigenic variation, a widely used strategy for immune evasion in pathogens, and telomere biology.

  13. Antitrypanosomal effect of methanolic extract of Zingiber officinale (ginger on Trypanosoma brucei brucei-infected Wistar mice

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    P. I. Kobo

    2014-10-01

    Full Text Available Aim: The study was carried out to determine the in vivo antitrypanosomal effect of methanolic extract of Zingiber officinale (ginger in Trypanosoma brucei brucei-infected mice. Materials and Methods: Twenty-five mice were randomly allocated into five groups of five animals each. Group I and II were given Tween 80 (1 ml/kg and diminazene aceturate (3.5 mg/kg to serve as untreated and treated controls, respectively. Groups III-V received the extract at 200, 400 and 800 mg/kg body weight, respectively. All treatments were given for 6 consecutive days and through the oral route. The mean body weight, mean survival period and daily level of parasitaemia were evaluated. Results: Acute toxicity showed the extract to be relatively safe. There was an insignificant increase in body weight and survival rate of mice treated with the extract. The level of parasitaemia in the extract treated groups was decreased. Conclusion: This study shows the in vivo potential of methanolic extract of Z. officinale in the treatment of trypanosomiasis.

  14. Cofactor-independent phosphoglycerate mutase is an essential gene in procyclic form Trypanosoma brucei.

    Science.gov (United States)

    Djikeng, Appolinaire; Raverdy, Sylvine; Foster, Jeremy; Bartholomeu, Daniella; Zhang, Yinhua; El-Sayed, Najib M; Carlow, Clotilde

    2007-03-01

    Glycolysis and gluconeogenesis are, in part, driven by the interconversion of 3- and 2-phosphoglycerate (3-PG and 2-PG) which is performed by phosphoglycerate mutases (PGAMs) which can be cofactor dependant (dPGAM) or cofactor independent (iPGAM). The African trypanosome, Trypanosoma brucei, possesses the iPGAM form which is thought to play an important role in glycolysis. Here, we report on the use of RNA interference to down-regulate the T. brucei iPGAM in procyclic form T. brucei and evaluation of the resulting phenotype. We first demonstrated biochemically that depletion of the steady state levels of iPGM mRNA correlates with a marked reduction of enzyme activity. We further show that iPGAM is required for cell growth in procyclic T. brucei.

  15. Hidden Markov Models for Gene Sequence Classification: Classifying the VSG genes in the Trypanosoma brucei Genome

    OpenAIRE

    Mesa, Andrea; Basterrech, Sebastián; Guerberoff, Gustavo; Alvarez-Valin, Fernando

    2015-01-01

    The article presents an application of Hidden Markov Models (HMMs) for pattern recognition on genome sequences. We apply HMM for identifying genes encoding the Variant Surface Glycoprotein (VSG) in the genomes of Trypanosoma brucei (T. brucei) and other African trypanosomes. These are parasitic protozoa causative agents of sleeping sickness and several diseases in domestic and wild animals. These parasites have a peculiar strategy to evade the host's immune system that consists in periodicall...

  16. Synthesis of novel guttiferone A derivatives: in-vitro evaluation toward Plasmodium falciparum, Trypanosoma brucei and Leishmania donovani.

    Science.gov (United States)

    Fromentin, Yann; Gaboriaud-Kolar, Nicolas; Lenta, Bruno Ndjakou; Wansi, Jean Duplex; Buisson, Didier; Mouray, Elisabeth; Grellier, Philippe; Loiseau, Philippe M; Lallemand, Marie-Christine; Michel, Sylvie

    2013-07-01

    The catechol pharmacomodulation of the natural product guttiferone A, isolated from the Symphonia globulifera tree, led to the semisynthesis of a collection of twenty derivatives. The ester and ether derivatives of guttiferone A were evaluated for their anti-plasmodial, trypanocidal and anti-leishmanial activities. Some compounds described below have shown potent antiparasitic activity against Plasmodium falciparum, Trypanosoma brucei and Leishmania donovani in a range from 1 to 5 μM. The evaluation of guttiferone A derivatives against VERO cells highlighted catechol modulations as an interesting tool to decrease the toxicity and keep the activity of this natural compound. The current study revealed new molecules as promising new antiparasitic drug candidates. PMID:23727538

  17. Channel-forming activities in the glycosomal fraction from the bloodstream form of Trypanosoma brucei.

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    Melisa Gualdron-López

    Full Text Available BACKGROUND: Glycosomes are a specialized form of peroxisomes (microbodies present in unicellular eukaryotes that belong to the Kinetoplastea order, such as Trypanosoma and Leishmania species, parasitic protists causing severe diseases of livestock and humans in subtropical and tropical countries. The organelles harbour most enzymes of the glycolytic pathway that is responsible for substrate-level ATP production in the cell. Glycolysis is essential for bloodstream-form Trypanosoma brucei and enzymes comprising this pathway have been validated as drug targets. Glycosomes are surrounded by a single membrane. How glycolytic metabolites are transported across the glycosomal membrane is unclear. METHODS/PRINCIPAL FINDINGS: We hypothesized that glycosomal membrane, similarly to membranes of yeast and mammalian peroxisomes, contains channel-forming proteins involved in the selective transfer of metabolites. To verify this prediction, we isolated a glycosomal fraction from bloodstream-form T. brucei and reconstituted solubilized membrane proteins into planar lipid bilayers. The electrophysiological characteristics of the channels were studied using multiple channel recording and single channel analysis. Three main channel-forming activities were detected with current amplitudes 70-80 pA, 20-25 pA, and 8-11 pA, respectively (holding potential +10 mV and 3.0 M KCl as an electrolyte. All channels were in fully open state in a range of voltages ±150 mV and showed no sub-conductance transitions. The channel with current amplitude 20-25 pA is anion-selective (P(K+/P(Cl-∼0.31, while the other two types of channels are slightly selective for cations (P(K+/P(Cl- ratios ∼1.15 and ∼1.27 for the high- and low-conductance channels, respectively. The anion-selective channel showed an intrinsic current rectification that may suggest a functional asymmetry of the channel's pore. CONCLUSIONS/SIGNIFICANCE: These results indicate that the membrane of glycosomes

  18. Mosaic VSGs and the scale of Trypanosoma brucei antigenic variation.

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    James P J Hall

    Full Text Available A main determinant of prolonged Trypanosoma brucei infection and transmission and success of the parasite is the interplay between host acquired immunity and antigenic variation of the parasite variant surface glycoprotein (VSG coat. About 0.1% of trypanosome divisions produce a switch to a different VSG through differential expression of an archive of hundreds of silent VSG genes and pseudogenes, but the patterns and extent of the trypanosome diversity phenotype, particularly in chronic infection, are unclear. We applied longitudinal VSG cDNA sequencing to estimate variant richness and test whether pseudogenes contribute to antigenic variation. We show that individual growth peaks can contain at least 15 distinct variants, are estimated computationally to comprise many more, and that antigenically distinct 'mosaic' VSGs arise from segmental gene conversion between donor VSG genes or pseudogenes. The potential for trypanosome antigenic variation is probably much greater than VSG archive size; mosaic VSGs are core to antigenic variation and chronic infection.

  19. MIF Contributes to Trypanosoma brucei Associated Immunopathogenicity Development

    Science.gov (United States)

    Stijlemans, Benoît; Leng, Lin; Brys, Lea; Sparkes, Amanda; Vansintjan, Liese; Caljon, Guy; Raes, Geert; Van Den Abbeele, Jan; Van Ginderachter, Jo A.; Beschin, Alain

    2014-01-01

    African trypanosomiasis is a chronic debilitating disease affecting the health and economic well-being of many people in developing countries. The pathogenicity associated with this disease involves a persistent inflammatory response, whereby M1-type myeloid cells, including Ly6Chigh inflammatory monocytes, are centrally implicated. A comparative gene analysis between trypanosusceptible and trypanotolerant animals identified MIF (macrophage migrating inhibitory factor) as an important pathogenic candidate molecule. Using MIF-deficient mice and anti-MIF antibody treated mice, we show that MIF mediates the pathogenic inflammatory immune response and increases the recruitment of inflammatory monocytes and neutrophils to contribute to liver injury in Trypanosoma brucei infected mice. Moreover, neutrophil-derived MIF contributed more significantly than monocyte-derived MIF to increased pathogenic liver TNF production and liver injury during trypanosome infection. MIF deficient animals also featured limited anemia, coinciding with increased iron bio-availability, improved erythropoiesis and reduced RBC clearance during the chronic phase of infection. Our data suggest that MIF promotes the most prominent pathological features of experimental trypanosome infections (i.e. anemia and liver injury), and prompt considering MIF as a novel target for treatment of trypanosomiasis-associated immunopathogenicity. PMID:25255103

  20. MIF contributes to Trypanosoma brucei associated immunopathogenicity development.

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    Benoît Stijlemans

    2014-09-01

    Full Text Available African trypanosomiasis is a chronic debilitating disease affecting the health and economic well-being of many people in developing countries. The pathogenicity associated with this disease involves a persistent inflammatory response, whereby M1-type myeloid cells, including Ly6C(high inflammatory monocytes, are centrally implicated. A comparative gene analysis between trypanosusceptible and trypanotolerant animals identified MIF (macrophage migrating inhibitory factor as an important pathogenic candidate molecule. Using MIF-deficient mice and anti-MIF antibody treated mice, we show that MIF mediates the pathogenic inflammatory immune response and increases the recruitment of inflammatory monocytes and neutrophils to contribute to liver injury in Trypanosoma brucei infected mice. Moreover, neutrophil-derived MIF contributed more significantly than monocyte-derived MIF to increased pathogenic liver TNF production and liver injury during trypanosome infection. MIF deficient animals also featured limited anemia, coinciding with increased iron bio-availability, improved erythropoiesis and reduced RBC clearance during the chronic phase of infection. Our data suggest that MIF promotes the most prominent pathological features of experimental trypanosome infections (i.e. anemia and liver injury, and prompt considering MIF as a novel target for treatment of trypanosomiasis-associated immunopathogenicity.

  1. Stearoyl-CoA desaturase is an essential enzyme for the parasitic protist Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Alloatti, Andres [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina); Gupta, Shreedhara; Gualdron-Lopez, Melisa; Nguewa, Paul A. [Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Universite Catholique de Louvain, Brussels (Belgium); Altabe, Silvia G. [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina); Deumer, Gladys; Wallemacq, Pierre [Department of Clinical Chemistry, Cliniques Universitaires Saint-Luc, LTAP, Universite Catholique de Louvain, Brussels (Belgium); Michels, Paul A.M. [Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Universite Catholique de Louvain, Brussels (Belgium); Uttaro, Antonio D., E-mail: toniuttaro@yahoo.com.ar [Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Santa Fe (Argentina)

    2011-08-26

    Highlights: {yields} Inhibiting {Delta}9 desaturase drastically changes T. brucei's fatty-acid composition. {yields} Isoxyl specifically inhibits the {Delta}9 desaturase causing a growth arrest. {yields} RNA interference of desaturase expression causes a similar effect. {yields} Feeding T. brucei-infected mice with Isoxyl decreases the parasitemia. {yields} 70% of Isoxyl-treated mice survived the trypanosome infection. -- Abstract: Trypanosoma brucei, the etiologic agent of sleeping sickness, is exposed to important changes in nutrients and temperature during its life cycle. To adapt to these changes, the fluidity of its membranes plays a crucial role. This fluidity, mediated by the fatty-acid composition, is regulated by enzymes named desaturases. We have previously shown that the oleoyl desaturase is essential for Trypanosoma cruzi and T. brucei. In this work, we present experimental support for the relevance of stearoyl-CoA desaturase (SCD) for T. brucei's survival, in both its insect or procyclic-form (PCF) and bloodstream-form (BSF) stages. We evaluated this essentiality in two different ways: by generating a SCD knocked-down parasite line using RNA interference, and by chemical inhibition of the enzyme with two compounds, Isoxyl and a thiastearate with the sulfur atom at position 10 (10-TS). The effective concentration for 50% growth inhibition (EC{sub 50}) of PCF was 1.0 {+-} 0.2 {mu}M for Isoxyl and 5 {+-} 2 {mu}M for 10-TS, whereas BSF appeared more susceptible with EC{sub 50} values 0.10 {+-} 0.03 {mu}M (Isoxyl) and 1.0 {+-} 0.6 {mu}M (10-TS). RNA interference showed to be deleterious for both stages of the parasite. In addition, T. brucei-infected mice were fed with Isoxyl, causing a reduction of the parasitemia and an increase of the rodents' survival.

  2. Eleganolone, a Diterpene from the French Marine Alga Bifurcaria bifurcata Inhibits Growth of the Human Pathogens Trypanosoma brucei and Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Anne-Marie Rusig

    2013-02-01

    Full Text Available Organic extracts of 20 species of French seaweed have been screened against Trypanosoma brucei rhodesiense trypomastigotes, the parasite responsible for sleeping sickness. These extracts have previously shown potent antiprotozoal activities in vitro against Plasmodium falciparum and Leishmania donovani. The selectivity of the extracts was also evaluated by testing cytotoxicity on a mammalian L6 cell line. The ethyl acetate extract of the brown seaweed, Bifurcaria bifurcata, showed strong trypanocidal activity with a mild selectivity index (IC50 = 0.53 µg/mL; selectivity index (SI = 11.6. Bio-guided fractionation led to the isolation of eleganolone, the main diterpenoid isolated from this species. Eleganolone contributes only mildly to the trypanocidal activity of the ethyl acetate extract (IC50 = 45.0 µM, SI = 4.0. However, a selective activity against P. falciparum erythrocytic stages in vitro has been highlighted (IC50 = 7.9 µM, SI = 21.6.

  3. Eleganolone, a Diterpene from the French Marine Alga Bifurcaria bifurcata Inhibits Growth of the Human Pathogens Trypanosoma brucei and Plasmodium falciparum

    Science.gov (United States)

    Gallé, Jean-Baptiste; Attioua, Barthélémy; Kaiser, Marcel; Rusig, Anne-Marie; Lobstein, Annelise; Vonthron-Sénécheau, Catherine

    2013-01-01

    Organic extracts of 20 species of French seaweed have been screened against Trypanosoma brucei rhodesiense trypomastigotes, the parasite responsible for sleeping sickness. These extracts have previously shown potent antiprotozoal activities in vitro against Plasmodium falciparum and Leishmania donovani. The selectivity of the extracts was also evaluated by testing cytotoxicity on a mammalian L6 cell line. The ethyl acetate extract of the brown seaweed, Bifurcaria bifurcata, showed strong trypanocidal activity with a mild selectivity index (IC50 = 0.53 µg/mL; selectivity index (SI) = 11.6). Bio-guided fractionation led to the isolation of eleganolone, the main diterpenoid isolated from this species. Eleganolone contributes only mildly to the trypanocidal activity of the ethyl acetate extract (IC50 = 45.0 µM, SI = 4.0). However, a selective activity against P. falciparum erythrocytic stages in vitro has been highlighted (IC50 = 7.9 µM, SI = 21.6). PMID:23442789

  4. Procyclic Trypanosoma brucei do not use Krebs cycle activity for energy generation

    NARCIS (Netherlands)

    Weelden, van S.W.H.; Fast, B.; Vogt, A.; Meer, van der P.; Saas, J.; Hellemond, van J.J.; Tielens, A.G.M.; Boshart, M.

    2003-01-01

    The importance of a functional Krebs cycle for energy generation in the procyclic stage of Trypanosoma brucei was investigated under physiological conditions during logarithmic phase growth of a pleomorphic parasite strain. Wild type procyclic cells and mutants with targeted deletion of the gene cod

  5. Dynamic Modelling under Uncertainty : The Case of Trypanosoma brucei Energy Metabolism

    NARCIS (Netherlands)

    Achcar, Fiona; Kerkhoven, Eduard J.; Bakker, Barbara M.; Barrett, Michael P.; Breitling, Rainer; Papin, Jason A.

    2012-01-01

    Kinetic models of metabolism require detailed knowledge of kinetic parameters. However, due to measurement errors or lack of data this knowledge is often uncertain. The model of glycolysis in the parasitic protozoan Trypanosoma brucei is a particularly well analysed example of a quantitative metabol

  6. Handling Uncertainty in Dynamic Models : The Pentose Phosphate Pathway in Trypanosoma brucei

    NARCIS (Netherlands)

    Kerkhoven, Eduard J.; Achcar, Fiona; Alibu, Vincent P.; Burchmore, Richard J.; Gilbert, Ian H.; Trybilo, Maciej; Driessen, Nicole N.; Gilbert, David; Breitling, Rainer; Bakker, Barbara M.; Barrett, Michael P.

    2013-01-01

    Dynamic models of metabolism can be useful in identifying potential drug targets, especially in unicellular organisms. A model of glycolysis in the causative agent of human African trypanosomiasis, Trypanosoma brucei, has already shown the utility of this approach. Here we add the pentose phosphate

  7. Telomere length affects the frequency and mechanism of antigenic variation in Trypanosoma brucei.

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    Galadriel A Hovel-Miner

    Full Text Available Trypanosoma brucei is a master of antigenic variation and immune response evasion. Utilizing a genomic repertoire of more than 1000 Variant Surface Glycoprotein-encoding genes (VSGs, T. brucei can change its protein coat by "switching" from the expression of one VSG to another. Each active VSG is monoallelically expressed from only one of approximately 15 subtelomeric sites. Switching VSG expression occurs by three predominant mechanisms, arguably the most significant of which is the non-reciprocal exchange of VSG containing DNA by duplicative gene conversion (GC. How T. brucei orchestrates its complex switching mechanisms remains to be elucidated. Recent work has demonstrated that an exogenous DNA break in the active site could initiate a GC based switch, yet the source of the switch-initiating DNA lesion under natural conditions is still unknown. Here we investigated the hypothesis that telomere length directly affects VSG switching. We demonstrate that telomerase deficient strains with short telomeres switch more frequently than genetically identical strains with long telomeres and that, when the telomere is short, switching preferentially occurs by GC. Our data supports the hypothesis that a short telomere at the active VSG expression site results in an increase in subtelomeric DNA breaks, which can initiate GC based switching. In addition to their significance for T. brucei and telomere biology, the findings presented here have implications for the many diverse pathogens that organize their antigenic genes in subtelomeric regions.

  8. Nucleic acid sequence-based amplification with oligochromatography for detection of Trypanosoma brucei in clinical samples

    NARCIS (Netherlands)

    C.M. Mugasa; T. Laurent; G.J. Schoone; P.A. Kager; G.W. Lubega; H.D.F.H. Schallig

    2009-01-01

    Molecular tools, such as real-time nucleic acid sequence-based amplification (NASBA) and PCR, have been developed to detect Trypanosoma brucei parasites in blood for the diagnosis of human African trypanosomiasis (HAT). Despite good sensitivity, these techniques are not implemented in HAT control pr

  9. The major transcripts of the kinetoplast Trypanosoma brucei are very small ribosomal RNA's.

    NARCIS (Netherlands)

    I.C. Eperon; J.W.G. Janssen; J.H.J. Hoeijmakers (Jan); P. Borst (Piet)

    1983-01-01

    textabstractThe nucleotide sequence has been determined of a 2.2 kb segment of kinetoplast DNA, which encodes the major mitochondrial transcripts (12S and 9S) of Trypanosoma brucei. The sequence shows that the 12S RNA is a large subunit rRNA, although sufficiently unusual for resistance to chloramph

  10. Biosynthesis of SUMOylated Proteins in Bacteria Using the Trypanosoma brucei Enzymatic System

    Science.gov (United States)

    Iribarren, Paula Ana; Berazategui, María Agustina; Cazzulo, Juan José; Alvarez, Vanina Eder

    2015-01-01

    Post-translational modification with the Small Ubiquitin-like Modifier (SUMO) is conserved in eukaryotic organisms and plays important regulatory roles in proteins affecting diverse cellular processes. In Trypanosoma brucei, member of one of the earliest branches in eukaryotic evolution, SUMO is essential for normal cell cycle progression and is likely to be involved in the epigenetic control of genes crucial for parasite survival, such as those encoding the variant surface glycoproteins. Molecular pathways modulated by SUMO have started to be discovered by proteomic studies; however, characterization of functional consequences is limited to a reduced number of targets. Here we present a bacterial strain engineered to produce SUMOylated proteins, by transferring SUMO from T. brucei together with the enzymes essential for its activation and conjugation. Due to the lack of background in E. coli, this system is useful to express and identify SUMOylated proteins directly in cell lysates by immunoblotting, and SUMOylated targets can be eventually purified for biochemical or structural studies. We applied this strategy to describe the ability of TbSUMO to form chains in vitro and to detect SUMOylation of a model substrate, PCNA both from Saccharomyces cerevisiae and from T. brucei. To further validate targets, we applied an in vitro deconjugation assay using the T. brucei SUMO-specific protease capable to revert the pattern of modification. This system represents a valuable tool for target validation, mutant generation and functional studies of SUMOylated proteins in trypanosomatids. PMID:26258470

  11. The lysosomotropic drug LeuLeu-OMe induces lysosome disruption and autophagy-independent cell death in Trypanosoma brucei

    OpenAIRE

    Hazel Xinyu Koh; Htay Mon Aye; Tan, Kevin S W; He, Cynthia Y.

    2015-01-01

    Background: Trypanosoma brucei is a blood-borne, protozoan parasite that causes African sleeping sickness in humans and nagana in animals. The current chemotherapy relies on only a handful of drugs that display undesirable toxicity, poor efficacy and drug-resistance. In this study, we explored the use of lysosomotropic drugs to induce bloodstream form T. brucei cell death via lysosome destabilization. Methods: We measured drug concentrations that inhibit cell proliferation by 50% (...

  12. Identification of a Wee1-like kinase gene essential for procyclic Trypanosoma brucei survival.

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    Natalia Y Boynak

    Full Text Available Regulation of eukaryotic cell cycle progression requires sequential activation and inactivation of cyclin-dependent kinases (CDKs. Activation of the cyclin B-cdc2 kinase complex is a pivotal step in mitotic initiation and the tyrosine kinase Wee1 is a key regulator of cell cycle sequence during G2/M transition and inhibits mitotic entry by phosphorylating the inhibitory tyrosine 15 on the cdc2 M-phase-inducing kinase. Wee1 degradation is essential for the exit from the G2 phase. In trypanosomatids, little is known about the genes that regulate cyclin B-cdc2 complexes at the G2/M transition of their cell cycle. Although canonical tyrosine kinases are absent in the genome of trypanosomatids, phosphorylation on protein tyrosine residues has been reported in Trypanosoma brucei. Here, we characterized a Wee1-like protein kinase gene from T. brucei. Expression of TbWee1 in a Schizosaccharomyces pombe strain null for Wee1 inhibited cell division and caused cell elongation. This demonstrates the lengthening of G2, which provided cells with extra time to grow before dividing. The Wee1-like protein kinase was expressed in the procyclic and bloodstream proliferative slender forms of T. brucei and the role of Wee1 in cell cycle progression was analyzed by generating RNA interference cell lines. In the procyclic form of T. brucei, the knock-down of TbWee1 expression by RNAi led to inhibition of parasite growth. Abnormal phenotypes showing an increase in the percentage of cells with 1N0K, 0N1K and 2N1K were observed in these RNAi cell lines. Using parasites with a synchronized cell cycle, we demonstrated that TbWee1 is linked to the G2/M phase. We also showed that TbWee1 is an essential gene necessary for proper cell cycle progression and parasite growth in T. brucei. Our results provide evidence for the existence of a functional Wee1 in T. brucei with a potential role in cell division at G2/M.

  13. Alkaloids Induce Programmed Cell Death in Bloodstream Forms of Trypanosomes (Trypanosoma b. brucei

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    Michael Wink

    2008-10-01

    Full Text Available The potential induction of a programmed cell death (PCD in Trypanosoma b. brucei by 55 alkaloids of the quinoline, quinolizidine, isoquinoline, indole, terpene, tropane, steroid, and piperidine type was studied by measuring DNA fragmentation and changes in mitochondrial membrane potential. For comparison, the induction of apoptosis by the same alkaloids in human leukemia cells (Jurkat APO-S was tested. Several alkaloids of the isoquinoline, quinoline, indole and steroidal type (berberine, chelerythrine, emetine, sanguinarine, quinine, ajmalicine, ergotamine, harmine, vinblastine, vincristine, colchicine, chaconine, demissidine and veratridine induced programmed cell death, whereas quinolizidine, tropane, terpene and piperidine alkaloids were mostly inactive. Effective PCD induction (EC50 below 10 µM was caused in T. brucei by chelerythrine, emetine, sanguinarine, and chaconine. The active alkaloids can be characterized by their general property to inhibit protein biosynthesis, to intercalate DNA, to disturb membrane fluidity or to inhibit microtubule formation.

  14. Trypanosoma brucei Infection in asymptomatic greater Kudus (Tragelaphus strepsiceros) on a game ranch in Zambia.

    Science.gov (United States)

    Munang'andu, Hetron Mweemba; Siamudaala, Victor; Munyeme, Musso; Nambota, Andrew; Mutoloki, Stephen; Matandiko, Wigganson

    2010-03-01

    Trypomastogotes of Trypanosoma brucei were detected from 4 asymptomatic kudus (Tragelaphus strepsiceros) on a game ranch located approximately 45 km north east of Lusaka, Zambia. Blood smears examined from 14 wildlife species comprising of the impala (Aepyceros melampus), Kafue lechwe (kobus leche kafuensis), sable antelope (Hippotragus niger), tsessebe (Damaliscus lunatus), warthog (Phacochoerus aethiopicus), puku (Kobus vardoni), zebra (Equus burchelli), waterbuck (Kobus ellipsiprymnus), bushbuck (Tragelaphus scriptus), reedbuck (Redunca arundinum), wilderbeest (Connochaetes taurinus), hartebeest (Alcephelus lichtensteini), African buffalo (Syncerus caffer), and kudu (Tragelaphus strepsiceros) showed that only the kudu had T. brucei. Although game ranching has emerged to be a successful ex-situ conservation strategy aimed at saving the declining wildlife population in the National Parks, our findings suggest that it has the potential of aiding the re-distribution of animal diseases. Hence, there is a need for augmenting wildlife conservation with disease control strategies aimed at reducing the risk of disease transmission between wildlife and domestic animals. PMID:20333288

  15. Identification of Paralogous Life-Cycle Stage Specific Cytoskeletal Proteins in the Parasite Trypanosoma brucei

    OpenAIRE

    Neil Portman; Keith Gull

    2014-01-01

    The life cycle of the African trypanosome Trypanosoma brucei, is characterised by a transition between insect and mammalian hosts representing very different environments that present the parasite with very different challenges. These challenges are met by the expression of life-cycle stage-specific cohorts of proteins, which function in systems such as metabolism and immune evasion. These life-cycle transitions are also accompanied by morphological rearrangements orchestrated by microtubule ...

  16. Ribose 5-Phosphate Isomerase B Knockdown Compromises Trypanosoma brucei Bloodstream Form Infectivity

    OpenAIRE

    Inês Loureiro; Joana Faria; Christine Clayton; Sandra Macedo-Ribeiro; Nuno Santarém; Nilanjan Roy; Anabela Cordeiro-da-Siva; Joana Tavares

    2015-01-01

    Ribose 5-phosphate isomerase is an enzyme involved in the non-oxidative branch of the pentose phosphate pathway, and catalyzes the inter-conversion of D-ribose 5-phosphate and D-ribulose 5-phosphate. Trypanosomatids, including the agent of African sleeping sickness namely Trypanosoma brucei, have a type B ribose-5-phosphate isomerase. This enzyme is absent from humans, which have a structurally unrelated ribose 5-phosphate isomerase type A, and therefore has been proposed as an attractive dru...

  17. The promoter for a variant surface glycoprotein gene expression site in Trypanosoma brucei.

    OpenAIRE

    Zomerdijk, J C; Ouellette, M; ten Asbroek, A L; Kieft, R.; Bommer, A M; Clayton, C E; Borst, P

    1990-01-01

    The variant-specific surface glycoprotein (VSG) gene 221 of Trypanosoma brucei is transcribed as part of a 60 kb expression site (ES). We have identified the promoter controlling this multigene transcription unit by the use of 221 chromosome-enriched DNA libraries and VSG gene 221 expression site specific transcripts. The start of transcription was determined by hybridization and RNase protection analysis of nascent RNA. The 5' ends of the major transcripts coming from the initiation region m...

  18. Reconstitution of a surface transferrin binding complex in insect form Trypanosoma brucei.

    OpenAIRE

    Ligtenberg, M.J.; Bitter, W.; Kieft, R.; Steverding, D; Janssen, H.; Calafat, J.; Borst, P

    1994-01-01

    In the bloodstream of the mammalian host, Trypanosoma brucei takes up host transferrin by means of a high-affinity uptake system, presumably a transferrin receptor. Transferrin-binding activity is seen in the flagellar pocket and is absent in insect form trypanosomes. By transfection we have reconstituted a transferrin-binding complex in insect form trypanosomes. Formation of this complex requires the products of two genes that are part of a variant surface glycoprotein expression site, expre...

  19. Genetic validation of aminoacyl-tRNA synthetases as drug targets in Trypanosoma brucei.

    Science.gov (United States)

    Kalidas, Savitha; Cestari, Igor; Monnerat, Severine; Li, Qiong; Regmi, Sandesh; Hasle, Nicholas; Labaied, Mehdi; Parsons, Marilyn; Stuart, Kenneth; Phillips, Margaret A

    2014-04-01

    Human African trypanosomiasis (HAT) is an important public health threat in sub-Saharan Africa. Current drugs are unsatisfactory, and new drugs are being sought. Few validated enzyme targets are available to support drug discovery efforts, so our goal was to obtain essentiality data on genes with proven utility as drug targets. Aminoacyl-tRNA synthetases (aaRSs) are known drug targets for bacterial and fungal pathogens and are required for protein synthesis. Here we survey the essentiality of eight Trypanosoma brucei aaRSs by RNA interference (RNAi) gene expression knockdown, covering an enzyme from each major aaRS class: valyl-tRNA synthetase (ValRS) (class Ia), tryptophanyl-tRNA synthetase (TrpRS-1) (class Ib), arginyl-tRNA synthetase (ArgRS) (class Ic), glutamyl-tRNA synthetase (GluRS) (class 1c), threonyl-tRNA synthetase (ThrRS) (class IIa), asparaginyl-tRNA synthetase (AsnRS) (class IIb), and phenylalanyl-tRNA synthetase (α and β) (PheRS) (class IIc). Knockdown of mRNA encoding these enzymes in T. brucei mammalian stage parasites showed that all were essential for parasite growth and survival in vitro. The reduced expression resulted in growth, morphological, cell cycle, and DNA content abnormalities. ThrRS was characterized in greater detail, showing that the purified recombinant enzyme displayed ThrRS activity and that the protein localized to both the cytosol and mitochondrion. Borrelidin, a known inhibitor of ThrRS, was an inhibitor of T. brucei ThrRS and showed antitrypanosomal activity. The data show that aaRSs are essential for T. brucei survival and are likely to be excellent targets for drug discovery efforts. PMID:24562907

  20. A Pre-clinical Animal Model of Trypanosoma brucei Infection Demonstrating Cardiac Dysfunction

    OpenAIRE

    McCarroll, Charlotte S; Rossor, Charlotte L.; Linda R Morrison; Morrison, Liam J.; Loughrey, Christopher M.

    2015-01-01

    Author Summary African trypanosomiasis (AT) is a disease caused by the single-celled protozoan parasite Trypanosoma brucei. In humans, AT causes neurological problems including sleep disturbances, which give the disease its colloquial name of “sleeping sickness”. Much of the focus of AT research has been on the neurological deficits, but other major organs are also affected, including the heart. Previous studies in humans and animals with AT have identified heart abnormalities such as contrac...

  1. An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei.

    Science.gov (United States)

    de Macêdo, Juan P; Schumann Burkard, Gabriela; Niemann, Moritz; Barrett, Michael P; Vial, Henri; Mäser, Pascal; Roditi, Isabel; Schneider, André; Bütikofer, Peter

    2015-05-01

    Elucidating the mechanism of action of trypanocidal compounds is an important step in the development of more efficient drugs against Trypanosoma brucei. In a screening approach using an RNAi library in T. brucei bloodstream forms, we identified a member of the mitochondrial carrier family, TbMCP14, as a prime candidate mediating the action of a group of anti-parasitic choline analogs. Depletion of TbMCP14 by inducible RNAi in both bloodstream and procyclic forms increased resistance of parasites towards the compounds by 7-fold and 3-fold, respectively, compared to uninduced cells. In addition, down-regulation of TbMCP14 protected bloodstream form mitochondria from a drug-induced decrease in mitochondrial membrane potential. Conversely, over-expression of the carrier in procyclic forms increased parasite susceptibility more than 13-fold. Metabolomic analyses of parasites over-expressing TbMCP14 showed increased levels of the proline metabolite, pyrroline-5-carboxylate, suggesting a possible involvement of TbMCP14 in energy production. The generation of TbMCP14 knock-out parasites showed that the carrier is not essential for survival of T. brucei bloodstream forms, but reduced parasite proliferation under standard culture conditions. In contrast, depletion of TbMCP14 in procyclic forms resulted in growth arrest, followed by parasite death. The time point at which parasite proliferation stopped was dependent on the major energy source, i.e. glucose versus proline, in the culture medium. Together with our findings that proline-dependent ATP production in crude mitochondria from TbMCP14-depleted trypanosomes was reduced compared to control mitochondria, the study demonstrates that TbMCP14 is involved in energy production in T. brucei. Since TbMCP14 belongs to a trypanosomatid-specific clade of mitochondrial carrier family proteins showing very poor similarity to mitochondrial carriers of mammals, it may represent an interesting target for drug action or targeting. PMID

  2. An essential signal peptide peptidase identified in an RNAi screen of serine peptidases of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Catherine X Moss

    Full Text Available The serine peptidases of Trypanosoma brucei have been viewed as potential drug targets. In particular, the S9 prolyl oligopeptidase subfamily is thought to be a good avenue for drug discovery. This is based on the finding that some S9 peptidases are secreted and active in the mammalian bloodstream, and that they are a class of enzyme against which drugs have successfully been developed. We collated a list of all serine peptidases in T. brucei, identifying 20 serine peptidase genes, of which nine are S9 peptidases. We screened all 20 serine peptidases by RNAi to determine which, if any, are essential for bloodstream form T. brucei survival. All S9 serine peptidases were dispensable for parasite survival in vitro, even when pairs of similar genes, coding for oligopeptidase B or prolyl oligopeptidase, were targeted simultaneously. We also found no effect on parasite survival in an animal host when the S9 peptidases oligopeptidase B, prolyl oligopeptidase or dipeptidyl peptidase 8 were targeted. The only serine peptidase to emerge from the RNAi screen as essential was a putative type-I signal peptide peptidase (SPP1. This gene was essential for parasite survival both in vitro and in vivo. The growth defect conferred by RNAi depletion of SPP1 was rescued by expression of a functional peptidase from an RNAi resistant SPP1 gene. However, expression of catalytically inactive SPP1 was unable to rescue cells from the SPP1 depleted phenotype, demonstrating that SPP1 serine peptidase activity is necessary for T. brucei survival.

  3. Alkaloids Induce Programmed Cell Death in Bloodstream Forms of Trypanosomes (Trypanosoma b. brucei)

    OpenAIRE

    Michael Wink; Vera Rosenkranz

    2008-01-01

    The potential induction of a programmed cell death (PCD) in Trypanosoma b. brucei by 55 alkaloids of the quinoline, quinolizidine, isoquinoline, indole, terpene, tropane, steroid, and piperidine type was studied by measuring DNA fragmentation and changes in mitochondrial membrane potential. For comparison, the induction of apoptosis by the same alkaloids in human leukemia cells (Jurkat APO-S) was tested. Several alkaloids of the isoquinoline, quinoline, indole and steroidal type (berberine, c...

  4. An Atypical Mitochondrial Carrier That Mediates Drug Action in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Juan P de Macêdo

    2015-05-01

    Full Text Available Elucidating the mechanism of action of trypanocidal compounds is an important step in the development of more efficient drugs against Trypanosoma brucei. In a screening approach using an RNAi library in T. brucei bloodstream forms, we identified a member of the mitochondrial carrier family, TbMCP14, as a prime candidate mediating the action of a group of anti-parasitic choline analogs. Depletion of TbMCP14 by inducible RNAi in both bloodstream and procyclic forms increased resistance of parasites towards the compounds by 7-fold and 3-fold, respectively, compared to uninduced cells. In addition, down-regulation of TbMCP14 protected bloodstream form mitochondria from a drug-induced decrease in mitochondrial membrane potential. Conversely, over-expression of the carrier in procyclic forms increased parasite susceptibility more than 13-fold. Metabolomic analyses of parasites over-expressing TbMCP14 showed increased levels of the proline metabolite, pyrroline-5-carboxylate, suggesting a possible involvement of TbMCP14 in energy production. The generation of TbMCP14 knock-out parasites showed that the carrier is not essential for survival of T. brucei bloodstream forms, but reduced parasite proliferation under standard culture conditions. In contrast, depletion of TbMCP14 in procyclic forms resulted in growth arrest, followed by parasite death. The time point at which parasite proliferation stopped was dependent on the major energy source, i.e. glucose versus proline, in the culture medium. Together with our findings that proline-dependent ATP production in crude mitochondria from TbMCP14-depleted trypanosomes was reduced compared to control mitochondria, the study demonstrates that TbMCP14 is involved in energy production in T. brucei. Since TbMCP14 belongs to a trypanosomatid-specific clade of mitochondrial carrier family proteins showing very poor similarity to mitochondrial carriers of mammals, it may represent an interesting target for drug

  5. Procyclic Trypanosoma brucei do not use Krebs cycle activity for energy generation.

    Science.gov (United States)

    van Weelden, Susanne W H; Fast, Beate; Vogt, Achim; van der Meer, Pieter; Saas, Joachim; van Hellemond, Jaap J; Tielens, Aloysius G M; Boshart, Michael

    2003-04-11

    The importance of a functional Krebs cycle for energy generation in the procyclic stage of Trypanosoma brucei was investigated under physiological conditions during logarithmic phase growth of a pleomorphic parasite strain. Wild type procyclic cells and mutants with targeted deletion of the gene coding for aconitase were derived by synchronous in vitro differentiation from wild type and mutant (Delta aco::NEO/Delta aco::HYG) bloodstream stage parasites, respectively, where aconitase is not expressed and is dispensable. No differences in intracellular levels of glycolytic and Krebs cycle intermediates were found in procyclic wild type and mutant cells, except for citrate that accumulated up to 90-fold in the mutants, confirming the absence of aconitase activity. Surprisingly, deletion of aconitase did not change differentiation nor the growth rate or the intracellular ATP/ADP ratio in those cells. Metabolic studies using radioactively labeled substrates and NMR analysis demonstrated that glucose and proline were not degraded via the Krebs cycle to CO(2). Instead, glucose was degraded to acetate, succinate, and alanine, whereas proline was degraded to succinate. Importantly, there was absolutely no difference in the metabolic products released by wild type and aconitase knockout parasites, and both were for survival strictly dependent on respiration via the mitochondrial electron transport chain. Hence, although the Krebs cycle enzymes are present, procyclic T. brucei do not use Krebs cycle activity for energy generation, but the mitochondrial respiratory chain is essential for survival and growth. We therefore propose a revised model of the energy metabolism of procyclic T. brucei.

  6. Experimental Trypanosoma brucei infection at immediate post partum period:effects on dam and the offspring

    Institute of Scientific and Technical Information of China (English)

    Izuchukwu S Ochiogu; Chukwuka N Uchendu; John I Ihedioha

    2010-01-01

    Objective:To investigate the effects of immediate post-partum infection with Trypanosoma brucei (T. brucei) on dam and offspring. Methods:Sixty female Albino rats (Rattus norvegicus) weighing between 130-170 g were used as animal model. The animals were divided as follows:25 infected between 1-5 days post partum; 10 infected unbred as positive controls; and 25 uninfected as negative controls. The following parameters were evaluated:packed cell volume (PCV), level of parasitaemia, survival time, litter size and litter weight at birth and on days 7, 14 and 21 post delivery, using conventional methods. Possible trans-mammary transmission of infection to litter through milk was also assessed. Results:The results showed a comparatively (P<0.05) higher mean PCV value for the uninfected negative control on the 8th day post infection compared with the infected groups which corresponded with the increasing level of parasitaemia in the two infected groups. Mean litter size and litter weights were higher (P< 0.05) in the uninfected controls on the 21st day. Survival time in the infected groups were similar. No evidence of trans-mammary transfer of infection was recorded. Conclusion:T. brucei infection during immediate post partum period is detrimental to the dam and impairs growth of the offspring.

  7. Advancing Trypanosoma brucei genome annotation through ribosome profiling and spliced leader mapping.

    Science.gov (United States)

    Parsons, Marilyn; Ramasamy, Gowthaman; Vasconcelos, Elton J R; Jensen, Bryan C; Myler, Peter J

    2015-08-01

    Since the initial publication of the trypanosomatid genomes, curation has been ongoing. Here we make use of existing Trypanosoma brucei ribosome profiling data to provide evidence of ribosome occupancy (and likely translation) of mRNAs from 225 currently unannotated coding sequences (CDSs). A small number of these putative genes correspond to extra copies of previously annotated genes, but 85% are novel. The median size of these novels CDSs is small (81 aa), indicating that past annotation work has excelled at detecting large CDSs. Of the unique CDSs confirmed here, over half have candidate orthologues in other trypanosomatid genomes, most of which were not yet annotated as protein-coding genes. Nonetheless, approximately one-third of the new CDSs were found only in T. brucei subspecies. Using ribosome footprints, RNA-Seq and spliced leader mapping data, we updated previous work to definitively revise the start sites for 414 CDSs as compared to the current gene models. The data pointed to several regions of the genome that had sequence errors that altered coding region boundaries. Finally, we consolidated this data with our previous work to propose elimination of 683 putative genes as protein-coding and arrive at a view of the translatome of slender bloodstream and procyclic culture form T. brucei.

  8. Discovery of Inhibitors of Trypanosoma brucei by Phenotypic Screening of a Focused Protein Kinase Library.

    Science.gov (United States)

    Woodland, Andrew; Thompson, Stephen; Cleghorn, Laura A T; Norcross, Neil; De Rycker, Manu; Grimaldi, Raffaella; Hallyburton, Irene; Rao, Bhavya; Norval, Suzanne; Stojanovski, Laste; Brun, Reto; Kaiser, Marcel; Frearson, Julie A; Gray, David W; Wyatt, Paul G; Read, Kevin D; Gilbert, Ian H

    2015-11-01

    A screen of a focused kinase inhibitor library against Trypanosoma brucei rhodesiense led to the identification of seven series, totaling 121 compounds, which showed >50 % inhibition at 5 μm. Screening of these hits in a T. b. brucei proliferation assay highlighted three compounds with a 1H-imidazo[4,5-b]pyrazin-2(3H)-one scaffold that showed sub-micromolar activity and excellent selectivity against the MRC5 cell line. Subsequent rounds of optimisation led to the identification of compounds that exhibited good in vitro drug metabolism and pharmacokinetics (DMPK) properties, although in general this series suffered from poor solubility. A scaffold-hopping exercise led to the identification of a 1H-pyrazolo[3,4-b]pyridine scaffold, which retained potency. A number of examples were assessed in a T. b. brucei growth assay, which could differentiate static and cidal action. Compounds from the 1H-imidazo[4,5-b]pyrazin-2(3H)-one series were found to be either static or growth-slowing and not cidal. Compounds with the 1H-pyrazolo[3,4-b]pyridine scaffold were found to be cidal and showed an unusual biphasic nature in this assay, suggesting they act by at least two mechanisms.

  9. Ethanolamine phosphoglycerol attachment to eEF1A is not essential for normal growth of Trypanosoma brucei

    OpenAIRE

    Eva Greganova; Peter Bütikofer

    2012-01-01

    Eukaryotic elongation factor 1A (eEF1A) is the only protein modified by ethanolamine phosphoglycerol (EPG). In mammals and plants, EPG is attached to conserved glutamate residues located in eEF1A domains II and III, whereas in the unicellular eukaryote, Trypanosoma brucei, a single EPG moiety is attached to domain III. A biosynthetic precursor of EPG and structural requirements for EPG attachment to T. brucei eEF1A have been reported, but the role of this unique protein modification in cellul...

  10. Central Nervous System Parasitosis and Neuroinflammation Ameliorated by Systemic IL-10 Administration in Trypanosoma brucei-Infected Mice.

    Science.gov (United States)

    Rodgers, Jean; Bradley, Barbara; Kennedy, Peter G E; Sternberg, Jeremy M

    2015-01-01

    Invasion of the central nervous system (CNS) by African trypanosomes represents a critical step in the development of human African trypanosomiasis. In both clinical cases and experimental mouse infections it has been demonstrated that predisposition to CNS invasion is associated with a type 1 systemic inflammatory response. Using the Trypanosoma brucei brucei GVR35 experimental infection model, we demonstrate that systemic delivery of the counter-inflammatory cytokine IL-10 lowers plasma IFN-γ and TNF-α concentrations, CNS parasitosis and ameliorates neuro-inflammatory pathology and clinical symptoms of disease. The results provide evidence that CNS invasion may be susceptible to immunological attenuation.

  11. A mixed methods study of a health worker training intervention to increase syndromic referral for gambiense human African trypanosomiasis in South Sudan.

    Directory of Open Access Journals (Sweden)

    Jennifer J Palmer

    2014-03-01

    Full Text Available BACKGROUND: Active screening by mobile teams is considered the most effective method for detecting gambiense-type human African trypanosomiasis (HAT but constrained funding in many post-conflict countries limits this approach. Non-specialist health care workers (HCWs in peripheral health facilities could be trained to identify potential cases for testing based on symptoms. We tested a training intervention for HCWs in peripheral facilities in Nimule, South Sudan to increase knowledge of HAT symptomatology and the rate of syndromic referrals to a central screening and treatment centre. METHODOLOGY/PRINCIPAL FINDINGS: We trained 108 HCWs from 61/74 of the public, private and military peripheral health facilities in the county during six one-day workshops and assessed behaviour change using quantitative and qualitative methods. In four months prior to training, only 2/562 people passively screened for HAT were referred from a peripheral HCW (0 cases detected compared to 13/352 (2 cases detected in the four months after, a 6.5-fold increase in the referral rate observed by the hospital. Modest increases in absolute referrals received, however, concealed higher levels of referral activity in the periphery. HCWs in 71.4% of facilities followed-up had made referrals, incorporating new and pre-existing ideas about HAT case detection into referral practice. HCW knowledge scores of HAT symptoms improved across all demographic sub-groups. Of 71 HAT referrals made, two-thirds were from new referrers. Only 11 patients completed the referral, largely because of difficulties patients in remote areas faced accessing transportation. CONCLUSIONS/SIGNIFICANCE: The training increased knowledge and this led to more widespread appropriate HAT referrals from a low base. Many referrals were not completed, however. Increasing access to screening and/or diagnostic tests in the periphery will be needed for greater impact on case-detection in this context. These data

  12. Trypanosoma brucei modifies the tsetse salivary composition, altering the fly feeding behavior that favors parasite transmission.

    Directory of Open Access Journals (Sweden)

    Jan Van Den Abbeele

    Full Text Available Tsetse flies are the notorious transmitters of African trypanosomiasis, a disease caused by the Trypanosoma parasite that affects humans and livestock on the African continent. Metacyclic infection rates in natural tsetse populations with Trypanosoma brucei, including the two human-pathogenic subspecies, are very low, even in epidemic situations. Therefore, the infected fly/host contact frequency is a key determinant of the transmission dynamics. As an obligate blood feeder, tsetse flies rely on their complex salivary potion to inhibit host haemostatic reactions ensuring an efficient feeding. The results of this experimental study suggest that the parasite might promote its transmission through manipulation of the tsetse feeding behavior by modifying the saliva composition. Indeed, salivary gland Trypanosoma brucei-infected flies display a significantly prolonged feeding time, thereby enhancing the likelihood of infecting multiple hosts during the process of a single blood meal cycle. Comparison of the two major anti-haemostatic activities i.e. anti-platelet aggregation and anti-coagulation activity in these flies versus non-infected tsetse flies demonstrates a significant suppression of these activities as a result of the trypanosome-infection status. This effect was mainly related to the parasite-induced reduction in salivary gland gene transcription, resulting in a strong decrease in protein content and related biological activities. Additionally, the anti-thrombin activity and inhibition of thrombin-induced coagulation was even more severely hampered as a result of the trypanosome infection. Indeed, while naive tsetse saliva strongly inhibited human thrombin activity and thrombin-induced blood coagulation, saliva from T. brucei-infected flies showed a significantly enhanced thrombinase activity resulting in a far less potent anti-coagulation activity. These data clearly provide evidence for a trypanosome-mediated modification of the tsetse

  13. A Gateway® compatible vector for gene silencing in bloodstream form Trypanosoma brucei

    OpenAIRE

    Kalidas, Savitha; Li, Qiong; Margaret A Phillips

    2011-01-01

    RNA interference is the most rapid method for generation of conditional knockdown mutants in Trypanosoma brucei. The dual T7 promoter (pZJM) and the stem-loop vectors have been widely used to generate stable inducible RNAi cell lines with the latter providing tighter regulatory control. However, the steps for cloning stem-loop constructs are cumbersome requiring either multiple cloning steps or multi-fragment ligation reactions. We report the development of a vector (pTrypRNAiGate) derived fr...

  14. Development of Simplified Heterocyclic Acetogenin Analogues as Potent and Selective Trypanosoma brucei Inhibitors.

    Science.gov (United States)

    Florence, Gordon J; Fraser, Andrew L; Gould, Eoin R; King, Elizabeth F; Menzies, Stefanie K; Morris, Joanne C; Thomson, Marie I; Tulloch, Lindsay B; Zacharova, Marija K; Smith, Terry K

    2016-07-19

    Neglected tropical diseases caused by parasitic infections are an ongoing and increasing concern. They are a burden to human and animal health, having the most devastating effect on the world's poorest countries. Building upon our previously reported triazole analogues, in this study we describe the synthesis and biological testing of other novel heterocyclic acetogenin-inspired derivatives, namely 3,5-isoxazoles, furoxans, and furazans. Several of these compounds maintain low-micromolar levels of inhibition against Trypanosoma brucei, whilst having no observable inhibitory effect on mammalian cells, leading to the possibility of novel lead compounds for selective treatment. PMID:27283448

  15. Evidence for a degradosome-like complex in the mitochondria of Trypanosoma brucei

    OpenAIRE

    Mattiacio, Jonelle L.; Read, Laurie K.

    2009-01-01

    Mitochondrial RNA turnover in yeast involves the degradosome, composed of DSS-1 exoribonuclease and SUV3 RNA helicase. Here, we describe a degradosome-like complex, containing SUV3 and DSS-1 homologues, in the early branching protozoan, Trypanosoma brucei. TbSUV3 is mitochondrially localized and co-sediments with TbDSS-1 on glycerol gradients. Co-immunoprecipitation demonstrates that TbSUV3 and TbDSS-1 associate in a stable complex, which differs from the yeast degradosome in that it is not s...

  16. Trypanosoma Brucei Aquaglyceroporins Facilitate the Uptake of Arsenite and Antimonite in a pH Dependent Way

    Directory of Open Access Journals (Sweden)

    Néstor L. Uzcátegui

    2013-09-01

    Full Text Available Background: Trypanosoma brucei is a primitive parasitic protozoan that thrives in diverse environments such as the midgut of the tsetse fly and the blood of a mammalian host. For an adequate adaptation to these environments, the parasite´s aquaglyceroporins play an important role. Methods and Results: In order to test their ability to transport trivalent arsenic and antimony, we expressed the three known Trypanosoma brucei aquaglyceroporins (TbAQPs in the heterologous systems of yeast null aquaporin mutant and Xenopus laevis oocytes. For both expression systems, we found a pH dependent intracellular accumulation of As(III or Sb(III mediated by all of the three TbAQPs, with the exception of TbAQP1-As(III uptake. Additionally, we observed that Trypanosoma brucei aquaglyceroporins allow the passage of As(III in both directions. Conclusion: Taken together, these results demonstrated that T. brucei aquaglyceroporins can serve as entry routes for As(III and Sb(III into the parasitic cell, and that this uptake is pH sensitive. Therefore, aquaporins of protozoan parasites may be considered useful as a vehicle for drug delivery.

  17. Variations in maxi-circle and mini-circle sequences in kinetoplast DNAs from different Trypanosoma brucei strains.

    NARCIS (Netherlands)

    P. Borst (Piet); F. Fase-Fowler; J.H.J. Hoeijmakers (Jan); A.C.C. Frasch

    1980-01-01

    textabstractWe have compared a total of 30 recognition sites for eight restriction endonucleases on the 20-kilobase-pair maxi-circle of kinetoplast DNAs from five different Trypanosoma brucei strains. In addition to three polymorphic sites were have found a 5 kilobase-pair region that is not cleaved

  18. Evaluation of the In Vitro Efficacy of Artemisia annua, Rumex abyssinicus, and Catha edulis Forsk Extracts in Cancer and Trypanosoma brucei Cells.

    Science.gov (United States)

    Worku, Netsanet; Mossie, Andualem; Stich, August; Daugschies, Arwid; Trettner, Susanne; Hemdan, Nasr Y A; Birkenmeier, Gerd

    2013-01-01

    The current drugs against sleeping sickness are derived from cancer chemotherapeutic approaches. Herein, we aimed at evaluating the in vitro effect of alcoholic extracts of Artemisia annua (AMR), Rumex abyssinicus (RMA), and Catha edulis Forsk (CEF) on proliferation/viability of 1321N1 astrocytoma, MCF-7 breast cancer, THP-1 leukemia, and LNCaP, Du-145, and PC-3 prostate cancer cells and on Trypanosoma brucei cells. Proliferation of tumor cells was evaluated by WST-1 assay and viability/behaviour of T. brucei by cell counting and light microscopy. CEF was the most efficient growth inhibitor in comparison to AMR and RMA. Nevertheless, in LNCaP and THP-1 cells, all extracts significantly inhibited tumor growth at 3 μg/mL. All extracts inhibited proliferation of T. brucei cells in a concentration-dependent manner. Microscopic analysis revealed that 95% of the T. brucei cells died when exposed to 33 μg/mL CEF for 3 hrs. Similar results were obtained using 33 μg/mL AMR for 6 hrs. In case of RMA, however, higher concentrations were necessary to obtain similar effects on T. brucei. This demonstrates the antitumor efficacy of these extracts as well as their ability to dampen viability and proliferation of T. brucei, suggesting a common mechanism of action on highly proliferative cells, most probably by targeting cell metabolism. PMID:25937964

  19. Sec16 determines the size and functioning of the Golgi in the protist parasite, Trypanosoma brucei.

    Science.gov (United States)

    Sealey-Cardona, Marco; Schmidt, Katy; Demmel, Lars; Hirschmugl, Tatjana; Gesell, Tanja; Dong, Gang; Warren, Graham

    2014-06-01

    The Sec16 homologue in Trypanosoma brucei has been identified and characterized. TbSec16 colocalizes with COPII components at the single endoplasmic reticulum exit site (ERES), which is next to the single Golgi stack in the insect (procyclic) form of this organism. Depletion of TbSec16 reduces the size of the ERES and the Golgi, and slows growth and transport of a secretory marker to the cell surface; conversely, overexpression of TbSec16 increases the size of the ERES and Golgi but has no effect on growth or secretion. Together these data suggest that TbSec16 regulates the size of the ERES and Golgi and this size is set for optimal growth of the organism.

  20. Extracellular Vesicles from Trypanosoma brucei Mediate Virulence Factor Transfer and Cause Host Anemia.

    Science.gov (United States)

    Szempruch, Anthony J; Sykes, Steven E; Kieft, Rudo; Dennison, Lauren; Becker, Allison C; Gartrell, Anzio; Martin, William J; Nakayasu, Ernesto S; Almeida, Igor C; Hajduk, Stephen L; Harrington, John M

    2016-01-14

    Intercellular communication between parasites and with host cells provides mechanisms for parasite development, immune evasion, and disease pathology. Bloodstream African trypanosomes produce membranous nanotubes that originate from the flagellar membrane and disassociate into free extracellular vesicles (EVs). Trypanosome EVs contain several flagellar proteins that contribute to virulence, and Trypanosoma brucei rhodesiense EVs contain the serum resistance-associated protein (SRA) necessary for human infectivity. T. b. rhodesiense EVs transfer SRA to non-human infectious trypanosomes, allowing evasion of human innate immunity. Trypanosome EVs can also fuse with mammalian erythrocytes, resulting in rapid erythrocyte clearance and anemia. These data indicate that trypanosome EVs are organelles mediating non-hereditary virulence factor transfer and causing host erythrocyte remodeling, inducing anemia. PMID:26771494

  1. Trypanosoma brucei: Enrichment by UV of intergenic transcripts from the variable surface glycoprotein gene expression site

    International Nuclear Information System (INIS)

    The expression site for the variable surface glycoprotein (VSG) gene AnTat 1.3A of Trypanosoma brucei is 45 kilobases long and encompasses seven expression site-associated genes (ESAGs). After UV irradiation, several large transcripts from the putative promoter region were strongly enriched. We report that one such major transcript starts near the poly(A) addition site of the first gene (ESAG 7), spans the intergenic region, and extends to the poly(A) addition site of the second gene (ESAG 6), thus bypassing the normal 3' splice site of the ESAG 6 mRNA. Since this transcript is spliced, we conclude that UV irradiation does not inhibit splicing but stabilizes unstable processing products. This demonstrates that at least some intergenic regions of the VSG gene expression site are continuously transcribed in accordance with a polycistronic transcription model

  2. Processing of the glycosomal matrix-protein import receptor PEX5 of Trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Gualdrón-López, Melisa [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium); Michels, Paul A.M., E-mail: paul.michels@uclouvain.be [Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Brussels (Belgium)

    2013-02-01

    Highlights: ► Most eukaryotic cells have a single gene for the peroxin PEX5. ► PEX5 is sensitive to in vitro proteolysis in distantly related organisms. ► TbPEX5 undergoes N-terminal truncation in vitro and possibly in vivo. ► Truncated TbPEX5 is still capable of binding PTS1-containing proteins. ► PEX5 truncation is physiologically relevant or an evolutionary conserved artifact. -- Abstract: Glycolysis in kinetoplastid protists such as Trypanosoma brucei is compartmentalized in peroxisome-like organelles called glycosomes. Glycosomal matrix-protein import involves a cytosolic receptor, PEX5, which recognizes the peroxisomal-targeting signal type 1 (PTS1) present at the C-terminus of the majority of matrix proteins. PEX5 appears generally susceptible to in vitro proteolytic processing. On western blots of T. brucei, two PEX5 forms are detected with apparent M{sub r} of 100 kDa and 72 kDa. 5′-RACE-PCR showed that TbPEX5 is encoded by a unique transcript that can be translated into a protein of maximally 72 kDa. However, recombinant PEX5 migrates aberrantly in SDS–PAGE with an apparent M{sub r} of 100 kDa, similarly as observed for the native peroxin. In vitro protease susceptibility analysis of native and {sup 35}S-labelled PEX5 showed truncation of the 100 kDa form at the N-terminal side by unknown parasite proteases, giving rise to the 72 kDa form which remains functional for PTS1 binding. The relevance of these observations is discussed.

  3. Knockdown of Inner Arm Protein IC138 in Trypanosoma brucei Causes Defective Motility and Flagellar Detachment.

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    Corinne S Wilson

    Full Text Available Motility in the protozoan parasite Trypanosoma brucei is conferred by a single flagellum, attached alongside the cell, which moves the cell forward using a beat that is generated from tip-to-base. We are interested in characterizing components that regulate flagellar beating, in this study we extend the characterization of TbIC138, the ortholog of a dynein intermediate chain that regulates axonemal inner arm dynein f/I1. TbIC138 was tagged In situ-and shown to fractionate with the inner arm components of the flagellum. RNAi knockdown of TbIC138 resulted in significantly reduced protein levels, mild growth defect and significant motility defects. These cells tended to cluster, exhibited slow and abnormal motility and some cells had partially or fully detached flagella. Slight but significant increases were observed in the incidence of mis-localized or missing kinetoplasts. To document development of the TbIC138 knockdown phenotype over time, we performed a detailed analysis of flagellar detachment and motility changes over 108 hours following induction of RNAi. Abnormal motility, such as slow twitching or irregular beating, was observed early, and became progressively more severe such that by 72 hours-post-induction, approximately 80% of the cells were immotile. Progressively more cells exhibited flagellar detachment over time, but this phenotype was not as prevalent as immotility, affecting less than 60% of the population. Detached flagella had abnormal beating, but abnormal beating was also observed in cells with no flagellar detachment, suggesting that TbIC138 has a direct, or primary, effect on the flagellar beat, whereas detachment is a secondary phenotype of TbIC138 knockdown. Our results are consistent with the role of TbIC138 as a regulator of motility, and has a phenotype amenable to more extensive structure-function analyses to further elucidate its role in the control of flagellar beat in T. brucei.

  4. Population genetics of Trypanosoma brucei rhodesiense: clonality and diversity within and between foci.

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    Craig W Duffy

    2013-11-01

    Full Text Available African trypanosomes are unusual among pathogenic protozoa in that they can undergo their complete morphological life cycle in the tsetse fly vector with mating as a non-obligatory part of this development. Trypanosoma brucei rhodesiense, which infects humans and livestock in East and Southern Africa, has classically been described as a host-range variant of the non-human infective Trypanosoma brucei that occurs as stable clonal lineages. We have examined T. b. rhodesiense populations from East (Uganda and Southern (Malawi Africa using a panel of microsatellite markers, incorporating both spatial and temporal analyses. Our data demonstrate that Ugandan T. b. rhodesiense existed as clonal populations, with a small number of highly related genotypes and substantial linkage disequilibrium between pairs of loci. However, these populations were not stable as the dominant genotypes changed and the genetic diversity also reduced over time. Thus these populations do not conform to one of the criteria for strict clonality, namely stability of predominant genotypes over time, and our results show that, in a period in the mid 1990s, the previously predominant genotypes were not detected but were replaced by a novel clonal population with limited genetic relationship to the original population present between 1970 and 1990. In contrast, the Malawi T. b. rhodesiense population demonstrated significantly greater diversity and evidence for frequent genetic exchange. Therefore, the population genetics of T. b. rhodesiense is more complex than previously described. This has important implications for the spread of the single copy T. b. rhodesiense gene that allows human infectivity, and therefore the epidemiology of the human disease, as well as suggesting that these parasites represent an important organism to study the influence of optional recombination upon population genetic dynamics.

  5. Protein functional links in Trypanosoma brucei, identified by gene fusion analysis

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    Trimpalis Philip

    2011-07-01

    Full Text Available Abstract Background Domain or gene fusion analysis is a bioinformatics method for detecting gene fusions in one organism by comparing its genome to that of other organisms. The occurrence of gene fusions suggests that the two original genes that participated in the fusion are functionally linked, i.e. their gene products interact either as part of a multi-subunit protein complex, or in a metabolic pathway. Gene fusion analysis has been used to identify protein functional links in prokaryotes as well as in eukaryotic model organisms, such as yeast and Drosophila. Results In this study we have extended this approach to include a number of recently sequenced protists, four of which are pathogenic, to identify fusion linked proteins in Trypanosoma brucei, the causative agent of African sleeping sickness. We have also examined the evolution of the gene fusion events identified, to determine whether they can be attributed to fusion or fission, by looking at the conservation of the fused genes and of the individual component genes across the major eukaryotic and prokaryotic lineages. We find relatively limited occurrence of gene fusions/fissions within the protist lineages examined. Our results point to two trypanosome-specific gene fissions, which have recently been experimentally confirmed, one fusion involving proteins involved in the same metabolic pathway, as well as two novel putative functional links between fusion-linked protein pairs. Conclusions This is the first study of protein functional links in T. brucei identified by gene fusion analysis. We have used strict thresholds and only discuss results which are highly likely to be genuine and which either have already been or can be experimentally verified. We discuss the possible impact of the identification of these novel putative protein-protein interactions, to the development of new trypanosome therapeutic drugs.

  6. Inhibitors of the mitochondrial cytochrome b-c1 complex inhibit the cyanide-insensitive respiration of Trypanosoma brucei.

    Science.gov (United States)

    Turrens, J F; Bickar, D; Lehninger, A L

    1986-06-01

    The cyanide-insensitive respiration of bloodstream trypomastigote forms of Trypanosoma brucei (75 +/- 8 nmol O2 min-1(mg protein)-1) is completely inhibited by the mitochondrial ubiquinone-like inhibitors 2-hydroxy-3-undecyl-1,4-naphthoquinone (UHNQ) and 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole (UHDBT). The Ki values for UHDBT (30 nM) and UHNQ (2 microM) are much lower than the reported Ki for salicylhydroxamic acid (SHAM) (5 microM), a widely used inhibitor of the cyanide-insensitive oxidase. UHNQ also stimulated the glycerol-3-phosphate-dependent reduction of phenazine methosulfate, demonstrating that the site of UHNQ inhibition is on the terminal oxidase of the cyanide-insensitive respiration of T. brucei. These results suggest that a ubiquinone-like compound may act as an electron carrier between the two enzymatic components of the cyanide-insensitive glycerol-3-phosphate oxidase.

  7. Inhibitors of the mitochondrial cytochrome b-c1 complex inhibit the cyanide-insensitive respiration of Trypanosoma brucei.

    Science.gov (United States)

    Turrens, J F; Bickar, D; Lehninger, A L

    1986-06-01

    The cyanide-insensitive respiration of bloodstream trypomastigote forms of Trypanosoma brucei (75 +/- 8 nmol O2 min-1(mg protein)-1) is completely inhibited by the mitochondrial ubiquinone-like inhibitors 2-hydroxy-3-undecyl-1,4-naphthoquinone (UHNQ) and 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole (UHDBT). The Ki values for UHDBT (30 nM) and UHNQ (2 microM) are much lower than the reported Ki for salicylhydroxamic acid (SHAM) (5 microM), a widely used inhibitor of the cyanide-insensitive oxidase. UHNQ also stimulated the glycerol-3-phosphate-dependent reduction of phenazine methosulfate, demonstrating that the site of UHNQ inhibition is on the terminal oxidase of the cyanide-insensitive respiration of T. brucei. These results suggest that a ubiquinone-like compound may act as an electron carrier between the two enzymatic components of the cyanide-insensitive glycerol-3-phosphate oxidase. PMID:3016533

  8. Catalytic properties, localization, and in vivo role of Px IV, a novel tryparedoxin peroxidase of Trypanosoma brucei.

    Science.gov (United States)

    Liu, Ilon; Bogacz, Marta; Schaffroth, Corinna; Dirdjaja, Natalie; Krauth-Siegel, R Luise

    2016-06-01

    Px IV is a distant relative of the known glutathione peroxidase-type enzymes of African trypanosomes. Immunofluorescence microscopy of bloodstream cells expressing C-terminally Myc6-tagged Px IV revealed a mitochondrial localization. Recombinant Px IV possesses very low activity as glutathione peroxidase but catalyzes the trypanothione/tryparedoxin-dependent reduction of hydrogen peroxide and, even more efficiently, of arachidonic acid hydroperoxide. Neither overexpression in bloodstream cells nor the deletion of both alleles in bloodstream or procyclic parasites affected the in vitro proliferation. Trypanosoma brucei Px IV shares 58% of all residues with TcGPXII. The orthologous enzymes have in common their substrate preference for fatty acid hydroperoxides. However, the T. cruzi protein has been reported to be localized in the endoplasmic reticulum and to be specific for glutathione as reducing agent. Taken together, our data show that Px IV is a low abundant tryparedoxin peroxidase of T. brucei that is not essential, at least under culture conditions. PMID:27262262

  9. Functional dissection of T. brucei Protein Tyrosine Phosphatase 1 and investigation of its development as a therapeutic target

    OpenAIRE

    Ruberto, Irene

    2011-01-01

    Trypanosoma brucei undergoes developmentally regulated morphological and biochemical changes during its life cycle, being transmitted between the mammalian host and the tsetse fly. It is generally recognized that cellular responses to environmental changes are mediated through signalling pathways, but our understanding of trypanosome signal transduction during differentiation is limited. Protein Tyrosine Phosphatase 1 (TbPTP1) is the one of the few factors identified to b...

  10. A structural domain mediates attachment of ethanolamine phosphoglycerol to eukaryotic elongation factor 1A in Trypanosoma brucei.

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    Eva Greganova

    Full Text Available Ethanolamine phosphoglycerol (EPG represents a protein modification that so far has only been found in eukaryotic elongation factor 1A (eEF1A. In mammals and plants, EPG is covalently attached to two conserved glutamate residues located in domains II and III of eEF1A. In contrast, Trypanosoma brucei eEF1A contains a single EPG attached to Glu362 in domain III. The sequence and/or structural requirements for covalent linkage of EPG to eEF1A have not been determined for any organism. Using a combination of biosynthetic labelling of parasites with tritiated ethanolamine and mass spectrometry analyses, we demonstrate that replacement of Glu362 in T. brucei eEF1A by site-directed mutagenesis prevents EPG attachment, whereas single or multiple amino acid substitutions around the attachment site are not critical. In addition, by expressing a series of eEF1A deletion mutants in T. brucei procyclic forms, we demonstrate that a peptide consisting of 80 amino acids of domain III of eEF1A is sufficient for EPG attachment to occur. Furthermore, EPG addition also occurs if domain III of eEF1A is fused to a soluble reporter protein. To our knowledge, this is the first report addressing amino acid sequence, or structure, requirements for EPG modification of eEF1A in any organism. Using T. brucei as a model organism, we show that amino acid substitutions around the modification site are not critical for EPG attachment and that a truncated version of domain III of eEF1A is sufficient to mediate EPG addition.

  11. Comparative genomics reveals two novel RNAi factors in Trypanosoma brucei and provides insight into the core machinery.

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    Rebecca L Barnes

    Full Text Available The introduction ten years ago of RNA interference (RNAi as a tool for molecular exploration in Trypanosoma brucei has led to a surge in our understanding of the pathogenesis and biology of this human parasite. In particular, a genome-wide RNAi screen has recently been combined with next-generation Illumina sequencing to expose catalogues of genes associated with loss of fitness in distinct developmental stages. At present, this technology is restricted to RNAi-positive protozoan parasites, which excludes T. cruzi, Leishmania major, and Plasmodium falciparum. Therefore, elucidating the mechanism of RNAi and identifying the essential components of the pathway is fundamental for improving RNAi efficiency in T. brucei and for transferring the RNAi tool to RNAi-deficient pathogens. Here we used comparative genomics of RNAi-positive and -negative trypanosomatid protozoans to identify the repertoire of factors in T. brucei. In addition to the previously characterized Argonaute 1 (AGO1 protein and the cytoplasmic and nuclear Dicers, TbDCL1 and TbDCL2, respectively, we identified the RNA Interference Factors 4 and 5 (TbRIF4 and TbRIF5. TbRIF4 is a 3'-5' exonuclease of the DnaQ superfamily and plays a critical role in the conversion of duplex siRNAs to the single-stranded form, thus generating a TbAGO1-siRNA complex required for target-specific cleavage. TbRIF5 is essential for cytoplasmic RNAi and appears to act as a TbDCL1 cofactor. The availability of the core RNAi machinery in T. brucei provides a platform to gain mechanistic insights in this ancient eukaryote and to identify the minimal set of components required to reconstitute RNAi in RNAi-deficient parasites.

  12. High-resolution complex of papain with remnants of a cysteine protease inhibitor derived from Trypanosoma brucei

    OpenAIRE

    Alphey, Magnus S.; Hunter, William N.

    2006-01-01

    Attempts to cocrystallize the cysteine protease papain derived from the latex of Carica papaya with an inhibitor of cysteine proteases (ICP) from Trypanosoma brucei were unsuccessful. However, crystals of papain that diffracted to higher resolution, 1.5 Å, than other crystals of this archetypal cysteine protease were obtained, so the analysis was continued. Surprisingly, the substrate-binding cleft was occupied by two short peptide fragments which have been assigned as remnants of ICP. Compar...

  13. A target-based high throughput screen yields Trypanosoma brucei hexokinase small molecule inhibitors with antiparasitic activity.

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    Elizabeth R Sharlow

    Full Text Available BACKGROUND: The parasitic protozoan Trypanosoma brucei utilizes glycolysis exclusively for ATP production during infection of the mammalian host. The first step in this metabolic pathway is mediated by hexokinase (TbHK, an enzyme essential to the parasite that transfers the gamma-phospho of ATP to a hexose. Here we describe the identification and confirmation of novel small molecule inhibitors of bacterially expressed TbHK1, one of two TbHKs expressed by T. brucei, using a high throughput screening assay. METHODOLOGY/PRINCIPAL FINDINGS: Exploiting optimized high throughput screening assay procedures, we interrogated 220,233 unique compounds and identified 239 active compounds from which ten small molecules were further characterized. Computation chemical cluster analyses indicated that six compounds were structurally related while the remaining four compounds were classified as unrelated or singletons. All ten compounds were approximately 20-17,000-fold more potent than lonidamine, a previously identified TbHK1 inhibitor. Seven compounds inhibited T. brucei blood stage form parasite growth (0.03brucei parasites, Leishmania promastigotes, and mammalian cell lines. Analysis of two structurally related compounds, ebselen and SID 17387000, revealed that both were mixed inhibitors of TbHK1 with respect to ATP. Additionally, both compounds inhibited parasite lysate-derived HK activity. None of the compounds displayed structural similarity to known hexokinase inhibitors or human African trypanosomiasis therapeutics. CONCLUSIONS/SIGNIFICANCE: The novel chemotypes identified here could represent leads for future therapeutic development against the African trypanosome.

  14. Evolutionary consequences of a large duplication event in Trypanosoma brucei: Chromosomes 4 and 8 are partial duplicons

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    Jackson Andrew P

    2007-11-01

    Full Text Available Abstract Background Gene order along the genome sequence of the human parasite Trypanosoma brucei provides evidence for a 0.5 Mb duplication, comprising the 3' regions of chromosomes 4 and 8. Here, the principal aim was to examine the contribution made by this duplication event to the T. brucei genome sequence, emphasising the consequences for gene content and the evolutionary change subsequently experienced by paralogous gene copies. The duplicated region may be browsed online at http://www.genedb.org/genedb/tryp/48dup_image.jsp Results Comparisons of trypanosomatid genomes demonstrated widespread gene loss from each duplicon, but also showed that 47% of duplicated genes were retained on both chromosomes as paralogous loci. Secreted and surface-expressed genes were over-represented among retained paralogs, reflecting a bias towards important factors at the host-parasite interface, and consistent with a dosage-balance hypothesis. Genetic divergence in both coding and regulatory regions of retained paralogs was bimodal, with a deficit in moderately divergent paralogs; in particular, non-coding sequences were either conserved or entirely remodelled. The conserved paralogs included examples of remarkable sequence conservation, but also considerable divergence of both coding and regulatory regions. Sequence divergence typically displayed strong negative selection; but several features, such as asymmetric evolutionary rates, positively-selected codons and other non-neutral substitutions, suggested that divergence of some paralogs was driven by functional change. The absence of orthologs to retained paralogs in T. congolense indicated that the duplication event was specific to T. brucei. Conclusion The duplication of this chromosomal region doubled the dosage of many genes. Rather than creating 'more of the same', these results show that paralogs were structurally modified according to various evolutionary trajectories. The retention of paralogs, and

  15. Chemopreventive effect of methanolic extract of Azadirachta indica on experimental Trypanosoma brucei induced oxidative stress in dogs

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    Temidayo O Omobowale

    2015-01-01

    Full Text Available Introduction: The medicinal properties of Azadirachta indica have been harnessed for many years in the treatment of many diseases in both humans and animals. Materials and Methods: Twenty-five apparently healthy dogs weighing between 3 and 8 kg were randomly divided into five groups with five dogs in each group. Ameliorative effect of A. indica on erythrocyte antioxidant status and markers of oxidative stress were assessed. Liver and kidney function tests were also performed. Results: Pre-treatment with methanolic extract of Azadirachta indica (MEAI at different doses did not significantly alter the values of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase activity in Trypanosoma brucei infection. Although, serum creatinine significantly (P 0.05 difference compared to the values obtained in pre-treated animals. Pre-treatment with 100 mg/kg and 200 mg/kg of A. indica significantly (P < 0.05 decreased serum myeloperoxidase activity at 2 weeks post-infection with T. brucei. Conclusion: From this study, MEAI showed significant ability to attenuate oxidative stress and inflammation during experimental T. brucei infection.

  16. Ab initio identification of novel regulatory elements in the genome of Trypanosoma brucei by Bayesian inference on sequence segmentation.

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    Steven Kelly

    Full Text Available BACKGROUND: The rapid increase in the availability of genome information has created considerable demand for both comparative and ab initio predictive bioinformatic analyses. The biology laid bare in the genomes of many organisms is often novel, presenting new challenges for bioinformatic interrogation. A paradigm for this is the collected genomes of the kinetoplastid parasites, a group which includes Trypanosoma brucei the causative agent of human African trypanosomiasis. These genomes, though outwardly simple in organisation and gene content, have historically challenged many theories for gene expression regulation in eukaryotes. METHODOLOGY/PRINCIPLE FINDINGS: Here we utilise a Bayesian approach to identify local changes in nucleotide composition in the genome of T. brucei. We show that there are several elements which are found at the starts and ends of multicopy gene arrays and that there are compositional elements that are common to all intergenic regions. We also show that there is a composition-inversion element that occurs at the position of the trans-splice site. CONCLUSIONS/SIGNIFICANCE: The nature of the elements discovered reinforces the hypothesis that context dependant RNA secondary structure has an important influence on gene expression regulation in Trypanosoma brucei.

  17. Changes in blood sugar levels of rats experimentally infected withTrypanosoma brucei and treated with imidocarb dipropionate and diminazene aceturate

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Omamegbe Joseph Omalathebu

    2016-01-01

    Objective:To determine the effect ofTrypanosoma brucei (T. brucei) on blood sugar level of infected rats. Methods: The experiment was done with 42 albino rats grouped into 3 groups of 14 members each. Group A was uninfected (control group), Group B was infected withT. brucei and treated with diminazene aceturate, and Group C was infected withT. brucei and treated with imidocarb dipropionate. Blood samples were collected from the media canthus of the experimental rats on Days 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 for the assessment of change in blood sugar levels. The blood sugar levels were determined with a glucometer (Accu-chek active serialNo.GN:10023338). Results: By 4 to 5 days post infection, there was a significant increase (P 0.05) was observed in the groups when compared with the control group till Day 12 of the experiment. Conclusions:T. brucei caused a significant increase in blood sugar of infected rats.

  18. Flux Analysis of the Trypanosoma brucei Glycolysis Based on a Multiobjective-Criteria Bioinformatic Approach

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    Amine Ghozlane

    2012-01-01

    Full Text Available Trypanosoma brucei is a protozoan parasite of major of interest in discovering new genes for drug targets. This parasite alternates its life cycle between the mammal host(s (bloodstream form and the insect vector (procyclic form, with two divergent glucose metabolism amenable to in vitro culture. While the metabolic network of the bloodstream forms has been well characterized, the flux distribution between the different branches of the glucose metabolic network in the procyclic form has not been addressed so far. We present a computational analysis (called Metaboflux that exploits the metabolic topology of the procyclic form, and allows the incorporation of multipurpose experimental data to increase the biological relevance of the model. The alternatives resulting from the structural complexity of networks are formulated as an optimization problem solved by a metaheuristic where experimental data are modeled in a multiobjective function. Our results show that the current metabolic model is in agreement with experimental data and confirms the observed high metabolic flexibility of glucose metabolism. In addition, Metaboflux offers a rational explanation for the high flexibility in the ratio between final products from glucose metabolism, thsat is, flux redistribution through the malic enzyme steps.

  19. A new generation of T7 RNA polymerase-independent inducible expression plasmids for Trypanosoma brucei.

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    Jack Sunter

    Full Text Available Expression of transgenes is central to forward and reverse genetic analysis in Trypanosoma brucei. The inducible expression of transgenes in trypanosomes is based on the tetracycline repressor binding to a tetracycline operator to prevent transcription in the absence of tetracycline. The same inducible system is used to produce double-stranded RNA for RNAi knockdown of target genes. This study describes a new plasmid pSPR2.1 that drives consistent high-level expression of tetracycline repressor in procyclic form trypanosomes. A complementary expression plasmid, p3227, was constructed. The major difference between this and current plasmids is the separation of the inducible transgene and selectable marker promoters by the plasmid backbone. The plasmid p3227 was able to support inducible expression in cell lines containing pSPR2.1 as well as the established Lister 427 29-13 cell line. p3666, a derivative of p3227, was made for inducible expression of stem loop RNAi constructs and was effective for knockdown of DRBD3, which had proved problematic using existing RNAi plasmids with head-to-head promoters. The plasmid system was also able to support inducible transgene expression and DRBD3 RNAi knockdown in bloodstream form cells expressing tetracycline repressor from an integrated copy of the plasmid pHD1313.

  20. Immune Evasion Strategies of Trypanosoma brucei within the Mammalian Host: Progression to Pathogenicity

    Science.gov (United States)

    Stijlemans, Benoît; Caljon, Guy; Van Den Abbeele, Jan; Van Ginderachter, Jo A.; Magez, Stefan; De Trez, Carl

    2016-01-01

    The diseases caused by African trypanosomes (AT) are of both medical and veterinary importance and have adversely influenced the economic development of sub-Saharan Africa. Moreover, so far not a single field applicable vaccine exists, and chemotherapy is the only strategy available to treat the disease. These strictly extracellular protozoan parasites are confronted with different arms of the host’s immune response (cellular as well as humoral) and via an elaborate and efficient (vector)–parasite–host interplay they have evolved efficient immune escape mechanisms to evade/manipulate the entire host immune response. This is of importance, since these parasites need to survive sufficiently long in their mammalian/vector host in order to complete their life cycle/transmission. Here, we will give an overview of the different mechanisms AT (i.e. T. brucei as a model organism) employ, comprising both tsetse fly saliva and parasite-derived components to modulate host innate immune responses thereby sculpturing an environment that allows survival and development within the mammalian host.

  1. Synchronous expression of individual metacyclic variant surface glycoprotein genes in Trypanosoma brucei.

    Science.gov (United States)

    Ramey-Butler, Kiantra; Ullu, Elisabetta; Kolev, Nikolay G; Tschudi, Christian

    2015-01-01

    One distinctive feature of the Trypanosoma brucei life cycle is the presence of two discrete populations that are based on differential expression of variant surface glycoproteins (VSGs). Both are adapted to the environmental pressures they face and more importantly, both contribute directly to transmission. Metacyclics in the tsetse fly enable transmission to a new mammalian host, whereas bloodstream trypanosomes must avoid immune destruction to the extent that sufficient numbers are available for transmission, when the insect vector takes a blood meal. At present, there are few investigations on the molecular aspects of parasite biology in the tsetse vector and specifically about the activation of metacyclic VSG gene expression. Here we used an established in vitro differentiation system based on the overexpression of the RNA-binding protein 6 (RBP6), to monitor two metacyclic VSGs (VSG 397 and VSG 653) during development from procyclics to infectious metacyclic forms. We observed that activation of these two mVSGs was simultaneous both at the transcript and protein level, and manifested by the appearance of only one of the mVSGs in individual cells. PMID:25896436

  2. Identification and characterization of an unusual class I myosin involved in vesicle traffic in Trypanosoma brucei.

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    Diana Spitznagel

    Full Text Available Myosins are a multimember family of motor proteins with diverse functions in eukaryotic cells. African trypanosomes possess only two candidate myosins and thus represent a useful system for functional analysis of these motors. One of these candidates is an unusual class I myosin (TbMyo1 that is expressed at similar levels but organized differently during the life cycle of Trypanosoma brucei. This myosin localizes to the polarized endocytic pathway in bloodstream forms of the parasite. This organization is actin dependent. Knock down of TbMyo1 results in a significant reduction in endocytic activity, a cessation in cell division and eventually cell death. A striking morphological feature in these cells is an enlargement of the flagellar pocket, which is consistent with an imbalance in traffic to and from the surface. In contrast TbMyo1 is distributed throughout procyclic forms of the tsetse vector and a loss of approximately 90% of the protein has no obvious effects on growth or morphology. These results reveal a life cycle stage specific requirement for this myosin in essential endocytic traffic and represent the first description of the involvement of a motor protein in vesicle traffic in these parasites.

  3. Identification and characterization of an unusual class I myosin involved in vesicle traffic in Trypanosoma brucei.

    Science.gov (United States)

    Spitznagel, Diana; O'Rourke, John F; Leddy, Neal; Hanrahan, Orla; Nolan, Derek P

    2010-01-01

    Myosins are a multimember family of motor proteins with diverse functions in eukaryotic cells. African trypanosomes possess only two candidate myosins and thus represent a useful system for functional analysis of these motors. One of these candidates is an unusual class I myosin (TbMyo1) that is expressed at similar levels but organized differently during the life cycle of Trypanosoma brucei. This myosin localizes to the polarized endocytic pathway in bloodstream forms of the parasite. This organization is actin dependent. Knock down of TbMyo1 results in a significant reduction in endocytic activity, a cessation in cell division and eventually cell death. A striking morphological feature in these cells is an enlargement of the flagellar pocket, which is consistent with an imbalance in traffic to and from the surface. In contrast TbMyo1 is distributed throughout procyclic forms of the tsetse vector and a loss of approximately 90% of the protein has no obvious effects on growth or morphology. These results reveal a life cycle stage specific requirement for this myosin in essential endocytic traffic and represent the first description of the involvement of a motor protein in vesicle traffic in these parasites.

  4. Isothermal microcalorimetry, a new tool to monitor drug action against Trypanosoma brucei and Plasmodium falciparum.

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    Tanja Wenzler

    Full Text Available Isothermal microcalorimetry is an established tool to measure heat flow of physical, chemical or biological processes. The metabolism of viable cells produces heat, and if sufficient cells are present, their heat production can be assessed by this method. In this study, we investigated the heat flow of two medically important protozoans, Trypanosoma brucei rhodesiense and Plasmodium falciparum. Heat flow signals obtained for these pathogens allowed us to monitor parasite growth on a real-time basis as the signals correlated with the number of viable cells. To showcase the potential of microcalorimetry for measuring drug action on pathogenic organisms, we tested the method with three antitrypanosomal drugs, melarsoprol, suramin and pentamidine and three antiplasmodial drugs, chloroquine, artemether and dihydroartemisinin, each at two concentrations on the respective parasite. With the real time measurement, inhibition was observed immediately by a reduced heat flow compared to that in untreated control samples. The onset of drug action, the degree of inhibition and the time to death of the parasite culture could conveniently be monitored over several days. Microcalorimetry is a valuable element to be added to the toolbox for drug discovery for protozoal diseases such as human African trypanosomiasis and malaria. The method could probably be adapted to other protozoan parasites, especially those growing extracellularly.

  5. Identification of paralogous life-cycle stage specific cytoskeletal proteins in the parasite Trypanosoma brucei.

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    Neil Portman

    Full Text Available The life cycle of the African trypanosome Trypanosoma brucei, is characterised by a transition between insect and mammalian hosts representing very different environments that present the parasite with very different challenges. These challenges are met by the expression of life-cycle stage-specific cohorts of proteins, which function in systems such as metabolism and immune evasion. These life-cycle transitions are also accompanied by morphological rearrangements orchestrated by microtubule dynamics and associated proteins of the subpellicular microtubule array. Here we employed a gel-based comparative proteomic technique, Difference Gel Electrophoresis, to identify cytoskeletal proteins that are expressed differentially in mammalian infective and insect form trypanosomes. From this analysis we identified a pair of novel, paralogous proteins, one of which is expressed in the procyclic form and the other in the bloodstream form. We show that these proteins, CAP51 and CAP51V, localise to the subpellicular corset of microtubules and are essential for correct organisation of the cytoskeleton and successful cytokinesis in their respective life cycle stages. We demonstrate for the first time redundancy of function between life-cycle stage specific paralogous sets in the cytoskeleton and reveal modification of cytoskeletal components in situ prior to their removal during differentiation from the bloodstream form to the insect form. These specific results emphasise a more generic concept that the trypanosome genome encodes a cohort of cytoskeletal components that are present in at least two forms with life-cycle stage-specific expression.

  6. Dynamic modelling under uncertainty: the case of Trypanosoma brucei energy metabolism.

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    Fiona Achcar

    2012-01-01

    Full Text Available Kinetic models of metabolism require detailed knowledge of kinetic parameters. However, due to measurement errors or lack of data this knowledge is often uncertain. The model of glycolysis in the parasitic protozoan Trypanosoma brucei is a particularly well analysed example of a quantitative metabolic model, but so far it has been studied with a fixed set of parameters only. Here we evaluate the effect of parameter uncertainty. In order to define probability distributions for each parameter, information about the experimental sources and confidence intervals for all parameters were collected. We created a wiki-based website dedicated to the detailed documentation of this information: the SilicoTryp wiki (http://silicotryp.ibls.gla.ac.uk/wiki/Glycolysis. Using information collected in the wiki, we then assigned probability distributions to all parameters of the model. This allowed us to sample sets of alternative models, accurately representing our degree of uncertainty. Some properties of the model, such as the repartition of the glycolytic flux between the glycerol and pyruvate producing branches, are robust to these uncertainties. However, our analysis also allowed us to identify fragilities of the model leading to the accumulation of 3-phosphoglycerate and/or pyruvate. The analysis of the control coefficients revealed the importance of taking into account the uncertainties about the parameters, as the ranking of the reactions can be greatly affected. This work will now form the basis for a comprehensive Bayesian analysis and extension of the model considering alternative topologies.

  7. Fluorinated Sterols Are Suicide Inhibitors of Ergosterol Biosynthesis and Growth in Trypanosoma brucei.

    Science.gov (United States)

    Leaver, David J; Patkar, Presheet; Singha, Ujjal K; Miller, Matthew B; Haubrich, Brad A; Chaudhuri, Minu; Nes, W David

    2015-10-22

    Trypanosoma brucei, the causal agent for sleeping sickness, depends on ergosterol for growth. Here, we describe the effects of a mechanism-based inhibitor, 26-fluorolanosterol (26FL), which converts in vivo to a fluorinated substrate of the sterol C24-methyltransferase essential for sterol methylation and function of ergosterol, and missing from the human host. 26FL showed potent inhibition of ergosterol biosynthesis and growth of procyclic and bloodstream forms while having no effect on cholesterol biosynthesis or growth of human epithelial kidney cells. During exposure of cloned TbSMT to 26-fluorocholesta-5,7,24-trienol, the enzyme is gradually killed as a consequence of the covalent binding of the intermediate C25 cation to the active site (kcat/kinact = 0.26 min(-1)/0.24 min(-1); partition ratio of 1.08), whereas 26FL is non-productively bound. These results demonstrate that poisoning of ergosterol biosynthesis by a 26-fluorinated Δ(24)-sterol is a promising strategy for developing a new treatment for trypanosomiasis.

  8. Spliced leader trapping reveals widespread alternative splicing patterns in the highly dynamic transcriptome of Trypanosoma brucei.

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    Daniel Nilsson

    Full Text Available Trans-splicing of leader sequences onto the 5'ends of mRNAs is a widespread phenomenon in protozoa, nematodes and some chordates. Using parallel sequencing we have developed a method to simultaneously map 5'splice sites and analyze the corresponding gene expression profile, that we term spliced leader trapping (SLT. The method can be applied to any organism with a sequenced genome and trans-splicing of a conserved leader sequence. We analyzed the expression profiles and splicing patterns of bloodstream and insect forms of the parasite Trypanosoma brucei. We detected the 5' splice sites of 85% of the annotated protein-coding genes and, contrary to previous reports, found up to 40% of transcripts to be differentially expressed. Furthermore, we discovered more than 2500 alternative splicing events, many of which appear to be stage-regulated. Based on our findings we hypothesize that alternatively spliced transcripts present a new means of regulating gene expression and could potentially contribute to protein diversity in the parasite. The entire dataset can be accessed online at TriTrypDB or through: http://splicer.unibe.ch/.

  9. Identification of the mitochondrially encoded subunit 6 of F1FO ATPase in Trypanosoma brucei.

    Science.gov (United States)

    Škodová-Sveráková, Ingrid; Horváth, Anton; Maslov, Dmitri A

    2015-06-01

    Kinetoplast maxicircle DNA of trypanosomatids encodes eighteen proteins. RNA editing is required to confer translatability to mRNA for twelve of these. Sequence conservation of the predicted hydrophobic polypeptides indicates that they represent functional components of the respiratory chain. Yet, so far only two of those, cytochrome c oxidase subunit I and apocytochrome b of cytochrome c reductase, have been identified with biochemical methods. Here we report on identification of A6 subunit of F1FO ATPase encoded by a pan-edited mRNA in Trypanosoma brucei. The polypeptide was present among the (35)S-labeled mitochondrial translation products characterized by anomalous migration in denaturing 2D gels. It was identified as an ATPase subunit by co-migration with this complex in Blue Native 2D gels. A partial N-terminal sequence of the corresponding polypeptide present in the gel-purified ATPase complex from Leishmania tarentolae was consistent with the predicted A6 sequence. PMID:26276057

  10. THE MULTIPLE ROLES OF CYCLIN E1 IN CONTROLLING CELL CYCLE PROGRESSION AND CELLULAR MORPHOLOGY OF TRYPANOSOMA BRUCEI

    OpenAIRE

    Gourguechon, Stéphane; Savich, Jason M.; Ching C Wang

    2007-01-01

    Regulation of eukaryotic cell cycle progression requires sequential activation and inactivation of cyclin-dependent kinases. Previous RNA interference (RNAi) experiments in Trypanosoma brucei indicated that cyclin E1, cdc2-related kinase (CRK)1 and CRK2 are involved in regulating G1/S transition, whereas cyclin B2 and CRK3 play a pivotal role in controlling the G2/M checkpoint. To search for potential interactions between the other cyclins and CRKs that may not have been revealed by the RNAi ...

  11. Loop-mediated isothermal amplification (LAMP method for rapid detection of Trypanosoma brucei rhodesiense.

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    Zablon Kithinji Njiru

    Full Text Available Loop-mediated isothermal amplification (LAMP of DNA is a novel technique that rapidly amplifies target DNA under isothermal conditions. In the present study, a LAMP test was designed from the serum resistance-associated (SRA gene of Trypanosoma brucei rhodesiense, the cause of the acute form of African sleeping sickness, and used to detect parasite DNA from processed and heat-treated infected blood samples. The SRA gene is specific to T. b. rhodesiense and has been shown to confer resistance to lysis by normal human serum. The assay was performed at 62 degrees C for 1 h, using six primers that recognised eight targets. The template was varying concentrations of trypanosome DNA and supernatant from heat-treated infected blood samples. The resulting amplicons were detected using SYTO-9 fluorescence dye in a real-time thermocycler, visual observation after the addition of SYBR Green I, and gel electrophoresis. DNA amplification was detected within 35 min. The SRA LAMP test had an unequivocal detection limit of one pg of purified DNA (equivalent to 10 trypanosomes/ml and 0.1 pg (1 trypanosome/ml using heat-treated buffy coat, while the detection limit for conventional SRA PCR was approximately 1,000 trypanosomes/ml. The expected LAMP amplicon was confirmed through restriction enzyme RsaI digestion, identical melt curves, and sequence analysis. The reproducibility of the SRA LAMP assay using water bath and heat-processed template, and the ease in results readout show great potential for the diagnosis of T. b. rhodesiense in endemic regions.

  12. Genome-wide dissection of the quorum sensing signalling pathway in Trypanosoma brucei.

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    Mony, Binny M; MacGregor, Paula; Ivens, Alasdair; Rojas, Federico; Cowton, Andrew; Young, Julie; Horn, David; Matthews, Keith

    2014-01-30

    The protozoan parasites Trypanosoma brucei spp. cause important human and livestock diseases in sub-Saharan Africa. In mammalian blood, two developmental forms of the parasite exist: proliferative 'slender' forms and arrested 'stumpy' forms that are responsible for transmission to tsetse flies. The slender to stumpy differentiation is a density-dependent response that resembles quorum sensing in microbial systems and is crucial for the parasite life cycle, ensuring both infection chronicity and disease transmission. This response is triggered by an elusive 'stumpy induction factor' (SIF) whose intracellular signalling pathway is also uncharacterized. Laboratory-adapted (monomorphic) trypanosome strains respond inefficiently to SIF but can generate forms with stumpy characteristics when exposed to cell-permeable cAMP and AMP analogues. Exploiting this, we have used a genome-wide RNA interference library screen to identify the signalling components driving stumpy formation. In separate screens, monomorphic parasites were exposed to 8-(4-chlorophenylthio)-cAMP (pCPT-cAMP) or 8-pCPT-2'-O-methyl-5'-AMP to select cells that were unresponsive to these signals and hence remained proliferative. Genome-wide Ion Torrent based RNAi target sequencing identified cohorts of genes implicated in each step of the signalling pathway, from purine metabolism, through signal transducers (kinases, phosphatases) to gene expression regulators. Genes at each step were independently validated in cells naturally capable of stumpy formation, confirming their role in density sensing in vivo. The putative RNA-binding protein, RBP7, was required for normal quorum sensing and promoted cell-cycle arrest and transmission competence when overexpressed. This study reveals that quorum sensing signalling in trypanosomes shares similarities to fundamental quiescence pathways in eukaryotic cells, its components providing targets for quorum-sensing interference-based therapeutics.

  13. Enhanced succinic acid production in Aspergillus saccharolyticus by heterologous expression of fumarate reductase from Trypanosoma brucei.

    Science.gov (United States)

    Yang, Lei; Lübeck, Mette; Ahring, Birgitte K; Lübeck, Peter S

    2016-02-01

    Aspergillus saccharolyticus exhibits great potential as a cell factory for industrial production of dicarboxylic acids. In the analysis of the organic acid profile, A. saccharolyticus was cultivated in an acid production medium using two different pH conditions. The specific activities of the enzymes, pyruvate carboxylase (PYC), malate dehydrogenase (MDH), and fumarase (FUM), involved in the reductive tricarboxylic acid (rTCA) branch, were examined and compared in cells harvested from the acid production medium and a complete medium. The results showed that ambient pH had a significant impact on the pattern and the amount of organic acids produced by A. saccharolyticus. The wild-type strain produced higher amount of malic acid and succinic acid in the pH buffered condition (pH 6.5) compared with the pH non-buffered condition. The enzyme assays showed that the rTCA branch was active in the acid production medium as well as the complete medium, but the measured enzyme activities were different depending on the media. Furthermore, a soluble NADH-dependent fumarate reductase gene (frd) from Trypanosoma brucei was inserted and expressed in A. saccharolyticus. The expression of the frd gene led to an enhanced production of succinic acid in frd transformants compared with the wild-type in both pH buffered and pH non-buffered conditions with highest amount produced in the pH buffered condition (16.2 ± 0.5 g/L). This study demonstrates the feasibility of increasing succinic acid production through the cytosolic reductive pathway by genetic engineering in A. saccharolyticus.

  14. A monoclonal antibody marker for the exclusion-zone filaments of Trypanosoma brucei

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    Decossas Marion

    2008-07-01

    Full Text Available Abstract Background Trypanosoma brucei is a haemoflagellate pathogen of man, wild animals and domesticated livestock in central and southern Africa. In all life cycle stages this parasite has a single mitochondrion that contains a uniquely organised genome that is condensed into a flat disk-like structure called the kinetoplast. The kinetoplast is essential for insect form procyclic cells and therefore is a potential drug target. The kinetoplast is unique in nature because it consists of novel structural proteins and thousands of circular, interlocking, DNA molecules (kDNA. Secondly, kDNA replication is critically timed to coincide with nuclear S phase and new flagellum biogenesis. Thirdly, the kinetoplast is physically attached to the flagellum basal bodies via a structure called the tripartite attachment complex (TAC. The TAC consists of unilateral filaments (within the mitochondrion matrix, differentiated mitochondrial membranes and exclusion-zone filaments that extend from the distal end of the basal bodies. To date only one protein, p166, has been identified to be a component of the TAC. Results In the work presented here we provide data based on a novel EM technique developed to label and characterise cytoskeleton structures in permeabilised cells without extraction of mitochondrion membranes. We use this protocol to provide data on a new monoclonal antibody reagent (Mab 22 and illustrate the precise localisation of basal body-mitochondrial linker proteins. Mab 22 binds to these linker proteins (exclusion-zone filaments and provides a new tool for the characterisation of cytoskeleton mediated kinetoplast segregation. Conclusion The antigen(s recognised by Mab 22 are cytoskeletal, insensitive to extraction by high concentrations of non-ionic detergent, extend from the proximal region of basal bodies and bind to the outer mitochondrial membrane. This protein(s is the first component of the TAC exclusion-zone fibres to be identified. Mab 22

  15. Simulating the complex cell design of Trypanosoma brucei and its motility.

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    Davod Alizadehrad

    2015-01-01

    Full Text Available The flagellate Trypanosoma brucei, which causes the sleeping sickness when infecting a mammalian host, goes through an intricate life cycle. It has a rather complex propulsion mechanism and swims in diverse microenvironments. These continuously exert selective pressure, to which the trypanosome adjusts with its architecture and behavior. As a result, the trypanosome assumes a diversity of complex morphotypes during its life cycle. However, although cell biology has detailed form and function of most of them, experimental data on the dynamic behavior and development of most morphotypes is lacking. Here we show that simulation science can predict intermediate cell designs by conducting specific and controlled modifications of an accurate, nature-inspired cell model, which we developed using information from live cell analyses. The cell models account for several important characteristics of the real trypanosomal morphotypes, such as the geometry and elastic properties of the cell body, and their swimming mechanism using an eukaryotic flagellum. We introduce an elastic network model for the cell body, including bending rigidity and simulate swimming in a fluid environment, using the mesoscale simulation technique called multi-particle collision dynamics. The in silico trypanosome of the bloodstream form displays the characteristic in vivo rotational and translational motility pattern that is crucial for survival and virulence in the vertebrate host. Moreover, our model accurately simulates the trypanosome's tumbling and backward motion. We show that the distinctive course of the attached flagellum around the cell body is one important aspect to produce the observed swimming behavior in a viscous fluid, and also required to reach the maximal swimming velocity. Changing details of the flagellar attachment generates less efficient swimmers. We also simulate different morphotypes that occur during the parasite's development in the tsetse fly, and

  16. 3D Architecture of the Trypanosoma brucei Flagella Connector, a Mobile Transmembrane Junction.

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    Johanna L Höög

    2016-01-01

    Full Text Available Cellular junctions are crucial for the formation of multicellular organisms, where they anchor cells to each other and/or supportive tissue and enable cell-to-cell communication. Some unicellular organisms, such as the parasitic protist Trypanosoma brucei, also have complex cellular junctions. The flagella connector (FC is a three-layered transmembrane junction that moves with the growing tip of a new flagellum and attaches it to the side of the old flagellum. The FC moves via an unknown molecular mechanism, independent of new flagellum growth. Here we describe the detailed 3D architecture of the FC suggesting explanations for how it functions and its mechanism of motility.We have used a combination of electron tomography and cryo-electron tomography to reveal the 3D architecture of the FC. Cryo-electron tomography revealed layers of repetitive filamentous electron densities between the two flagella in the interstitial zone. Though the FC does not change in length and width during the growth of the new flagellum, the interstitial zone thickness decreases as the FC matures. This investigation also shows interactions between the FC layers and the axonemes of the new and old flagellum, sufficiently strong to displace the axoneme in the old flagellum. We describe a novel filament, the flagella connector fibre, found between the FC and the axoneme in the old flagellum.The FC is similar to other cellular junctions in that filamentous proteins bridge the extracellular space and are anchored to underlying cytoskeletal structures; however, it is built between different portions of the same cell and is unique because of its intrinsic motility. The detailed description of its structure will be an important tool to use in attributing structure / function relationships as its molecular components are discovered in the future. The FC is involved in the inheritance of cell shape, which is important for the life cycle of this human parasite.

  17. A novel high-throughput activity assay for the Trypanosoma brucei editosome enzyme REL1 and other RNA ligases

    Science.gov (United States)

    Zimmermann, Stephan; Hall, Laurence; Riley, Sean; Sørensen, Jesper; Amaro, Rommie E.; Schnaufer, Achim

    2016-01-01

    The protist parasite Trypanosoma brucei causes Human African trypanosomiasis (HAT), which threatens millions of people in sub-Saharan Africa. Without treatment the infection is almost always lethal. Current drugs for HAT are difficult to administer and have severe side effects. Together with increasing drug resistance this results in urgent need for new treatments. T. brucei and other trypanosomatid pathogens require a distinct form of post-transcriptional mRNA modification for mitochondrial gene expression. A multi-protein complex called the editosome cleaves mitochondrial mRNA, inserts or deletes uridine nucleotides at specific positions and re-ligates the mRNA. RNA editing ligase 1 (REL1) is essential for the re-ligation step and has no close homolog in the mammalian host, making it a promising target for drug discovery. However, traditional assays for RELs use radioactive substrates coupled with gel analysis and are not suitable for high-throughput screening of compound libraries. Here we describe a fluorescence-based REL activity assay. This assay is compatible with a 384-well microplate format and sensitive, satisfies statistical criteria for high-throughput methods and is readily adaptable for other polynucleotide ligases. We validated the assay by determining kinetic properties of REL1 and by identifying REL1 inhibitors in a library of small, pharmacologically active compounds. PMID:26400159

  18. TbPIF5 is a Trypanosoma brucei mitochondrial DNA helicase involved in processing of minicircle Okazaki fragments.

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    Beiyu Liu

    2009-09-01

    Full Text Available Trypanosoma brucei's mitochondrial genome, kinetoplast DNA (kDNA, is a giant network of catenated DNA rings. The network consists of a few thousand 1 kb minicircles and several dozen 23 kb maxicircles. Here we report that TbPIF5, one of T. brucei's six mitochondrial proteins related to Saccharomyces cerevisiae mitochondrial DNA helicase ScPIF1, is involved in minicircle lagging strand synthesis. Like its yeast homolog, TbPIF5 is a 5' to 3' DNA helicase. Together with other enzymes thought to be involved in Okazaki fragment processing, TbPIF5 localizes in vivo to the antipodal sites flanking the kDNA. Minicircles in wild type cells replicate unidirectionally as theta-structures and are unusual in that Okazaki fragments are not joined until after the progeny minicircles have segregated. We now report that overexpression of TbPIF5 causes premature removal of RNA primers and joining of Okazaki fragments on theta structures. Further elongation of the lagging strand is blocked, but the leading strand is completed and the minicircle progeny, one with a truncated H strand (ranging from 0.1 to 1 kb, are segregated. The minicircles with a truncated H strand electrophorese on an agarose gel as a smear. This replication defect is associated with kinetoplast shrinkage and eventual slowing of cell growth. We propose that TbPIF5 unwinds RNA primers after lagging strand synthesis, thus facilitating processing of Okazaki fragments.

  19. In Silico Identification and in Vitro Activity of Novel Natural Inhibitors of Trypanosoma brucei Glyceraldehyde-3-phosphate-dehydrogenase

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    Fabian C. Herrmann

    2015-09-01

    Full Text Available As part of our ongoing efforts to identify natural products with activity against pathogens causing neglected tropical diseases, we are currently performing an extensive screening of natural product (NP databases against a multitude of protozoan parasite proteins. Within this project, we screened a database of NPs from a commercial supplier, AnalytiCon Discovery (Potsdam, Germany, against Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH, a glycolytic enzyme whose inhibition deprives the parasite of energy supply. NPs acting as potential inhibitors of the mentioned enzyme were identified using a pharmacophore-based virtual screening and subsequent docking of the identified hits into the active site of interest. In a set of 700 structures chosen for the screening, 13 (1.9% were predicted to possess significant affinity towards the enzyme and were therefore tested in an in vitro enzyme assay using recombinant TbGAPDH. Nine of these in silico hits (69% showed significant inhibitory activity at 50 µM, of which two geranylated benzophenone derivatives proved to be particularly active with IC50 values below 10 µM. These compounds also showed moderate in vitro activity against T. brucei rhodesiense and may thus represent interesting starting points for further optimization.

  20. Tracking the Biogenesis and Inheritance of Subpellicular Microtubule in Trypanosoma brucei with Inducible YFP-α-Tubulin

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    Omar Sheriff

    2014-01-01

    Full Text Available The microtubule cytoskeleton forms the most prominent structural system in Trypanosoma brucei, undergoing extensive modifications during the cell cycle. Visualization of tyrosinated microtubules leads to a semiconservative mode of inheritance, whereas recent studies employing microtubule plus end tracking proteins have hinted at an asymmetric pattern of cytoskeletal inheritance. To further the knowledge of microtubule synthesis and inheritance during T. brucei cell cycle, the dynamics of the microtubule cytoskeleton was visualized by inducible YFP-α-tubulin expression. During new flagellum/flagellum attachment zone (FAZ biogenesis and cell growth, YFP-α-tubulin was incorporated mainly between the old and new flagellum/FAZ complexes. Cytoskeletal modifications at the posterior end of the cells were observed with EB1, a microtubule plus end binding protein, particularly during mitosis. Additionally, the newly formed microtubules segregated asymmetrically, with the daughter cell inheriting the new flagellum/FAZ complex retaining most of the new microtubules. Together, our results suggest an intimate connection between new microtubule formation and new FAZ assembly, consequently leading to asymmetric microtubule inheritance and cell division.

  1. Independent analysis of the flagellum surface and matrix proteomes provides insight into flagellum signaling in mammalian-infectious Trypanosoma brucei.

    Science.gov (United States)

    Oberholzer, Michael; Langousis, Gerasimos; Nguyen, HoangKim T; Saada, Edwin A; Shimogawa, Michelle M; Jonsson, Zophonias O; Nguyen, Steven M; Wohlschlegel, James A; Hill, Kent L

    2011-10-01

    The flagellum of African trypanosomes is an essential and multifunctional organelle that functions in motility, cell morphogenesis, and host-parasite interaction. Previous studies of the trypanosome flagellum have been limited by the inability to purify flagella without first removing the flagellar membrane. This limitation is particularly relevant in the context of studying flagellum signaling, as signaling requires surface-exposed proteins in the flagellar membrane and soluble signaling proteins in the flagellar matrix. Here we employ a combination of genetic and mechanical approaches to purify intact flagella from the African trypanosome, Trypanosoma brucei, in its mammalian-infectious stage. We combined flagellum purification with affinity-purification of surface-exposed proteins to conduct independent proteomic analyses of the flagellum surface and matrix fractions. The proteins identified encompass a broad range of molecular functionalities, including many predicted to function in signaling. Immunofluorescence and RNA interference studies demonstrate flagellum localization and function for proteins identified and provide insight into mechanisms of flagellum attachment and motility. The flagellum surface proteome includes many T. brucei-specific proteins and is enriched for proteins up-regulated in the mammalian-infectious stage of the parasite life-cycle. The combined results indicate that the flagellum surface presents a diverse and dynamic host-parasite interface that is well-suited for host-parasite signaling. PMID:21685506

  2. Genome-wide Analysis Reveals Extensive Functional Interaction between DNA Replication Initiation and Transcription in the Genome of Trypanosoma brucei

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    Calvin Tiengwe

    2012-07-01

    Full Text Available Identification of replication initiation sites, termed origins, is a crucial step in understanding genome transmission in any organism. Transcription of the Trypanosoma brucei genome is highly unusual, with each chromosome comprising a few discrete transcription units. To understand how DNA replication occurs in the context of such organization, we have performed genome-wide mapping of the binding sites of the replication initiator ORC1/CDC6 and have identified replication origins, revealing that both localize to the boundaries of the transcription units. A remarkably small number of active origins is seen, whose spacing is greater than in any other eukaryote. We show that replication and transcription in T. brucei have a profound functional overlap, as reducing ORC1/CDC6 levels leads to genome-wide increases in mRNA levels arising from the boundaries of the transcription units. In addition, ORC1/CDC6 loss causes derepression of silent Variant Surface Glycoprotein genes, which are critical for host immune evasion.

  3. Deviating the level of proliferating cell nuclear antigen in Trypanosoma brucei elicits distinct mechanisms for inhibiting proliferation and cell cycle progression.

    Science.gov (United States)

    Valenciano, Ana L; Ramsey, Aaron C; Mackey, Zachary B

    2015-01-01

    The DNA replication machinery is spatially and temporally coordinated in all cells to reproduce a single exact copy of the genome per division, but its regulation in the protozoan parasite Trypanosoma brucei is not well characterized. We characterized the effects of altering the levels of proliferating cell nuclear antigen, a key component of the DNA replication machinery, in bloodstream form T. brucei. This study demonstrated that tight regulation of TbPCNA levels was critical for normal proliferation and DNA replication in the parasite. Depleting TbPCNA mRNA reduced proliferation, severely diminished DNA replication, arrested the synthesis of new DNA and caused the parasites to accumulated in G2/M. Attenuating the parasite by downregulating TbPCNA caused it to become hypersensitive to hydroxyurea. Overexpressing TbPCNA in T. brucei arrested proliferation, inhibited DNA replication and prevented the parasite from exiting G2/M. These results indicate that distinct mechanisms of cell cycle arrest are associated with upregulating or downregulating TbPCNA. The findings of this study validate deregulating intra-parasite levels of TbPCNA as a potential strategy for therapeutically exploiting this target in bloodstream form T. brucei.

  4. Identification and Characterization of Hundreds of Potent and Selective Inhibitors of Trypanosoma brucei Growth from a Kinase-Targeted Library Screening Campaign

    Science.gov (United States)

    Diaz, Rosario; Luengo-Arratta, Sandra A.; Seixas, João D.; Amata, Emanuele; Devine, William; Cordon-Obras, Carlos; Rojas-Barros, Domingo I.; Jimenez, Elena; Ortega, Fatima; Crouch, Sabrinia; Colmenarejo, Gonzalo; Fiandor, Jose Maria; Martin, Jose Julio; Berlanga, Manuela; Gonzalez, Silvia; Manzano, Pilar; Navarro, Miguel; Pollastri, Michael P.

    2014-01-01

    In the interest of identification of new kinase-targeting chemotypes for target and pathway analysis and drug discovery in Trypanosomal brucei, a high-throughput screen of 42,444 focused inhibitors from the GlaxoSmithKline screening collection was performed against parasite cell cultures and counter-screened against human hepatocarcinoma (HepG2) cells. In this way, we have identified 797 sub-micromolar inhibitors of T. brucei growth that are at least 100-fold selective over HepG2 cells. Importantly, 242 of these hit compounds acted rapidly in inhibiting cellular growth, 137 showed rapid cidality. A variety of in silico and in vitro physicochemical and drug metabolism properties were assessed, and human kinase selectivity data were obtained, and, based on these data, we prioritized three compounds for pharmacokinetic assessment and demonstrated parasitological cure of a murine bloodstream infection of T. brucei rhodesiense with one of these compounds (NEU-1053). This work represents a successful implementation of a unique industrial-academic collaboration model aimed at identification of high quality inhibitors that will provide the parasitology community with chemical matter that can be utilized to develop kinase-targeting tool compounds. Furthermore these results are expected to provide rich starting points for discovery of kinase-targeting tool compounds for T. brucei, and new HAT therapeutics discovery programs. PMID:25340575

  5. A proteomics approach reveals molecular manipulators of distinct cellular processes in the salivary glands of Glossina m. morsitans in response to Trypanosoma b. brucei infections

    NARCIS (Netherlands)

    Kariithi, Henry M.; Boeren, Sjef; Murungi, Edwin K.; Vlak, Just M.; Abd-Alla, Adly M.M.

    2016-01-01

    Background: Glossina m. morsitans is the primary vector of the Trypanosoma brucei group, one of the causative agents of African trypanosomoses. The parasites undergo metacyclogenesis, i.e. transformation into the mammalian-infective metacyclic trypomastigote (MT) parasites, in the salivary glands

  6. Excreted/Secreted Proteins from Trypanosome Procyclic Strains

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    Celestine Michelle Atyame Nten

    2010-01-01

    Full Text Available Trypanosoma secretome was shown to be involved in parasite virulence and is suspected of interfering in parasite life-cycle steps such as establishment in the Glossina midgut, metacyclogenesis. Therefore, we attempted to identify the proteins secreted by procyclic strains of T. brucei gambiense and T. brucei brucei, responsible for human and animal trypanosomiasis, respectively. Using mass spectrometry, 427 and 483 nonredundant proteins were characterized in T. brucei brucei and T. brucei gambiense secretomes, respectively; 35% and 42% of the corresponding secretome proteins were specifically secreted by T. brucei brucei and T. brucei gambiense, respectively, while 279 proteins were common to both subspecies. The proteins were assigned to 12 functional classes. Special attention was paid to the most abundant proteases (14 families because of their potential implication in the infection process and nutrient supply. The presence of proteins usually secreted via an exosome pathway suggests that this type of process is involved in trypanosome ESP secretion. The overall results provide leads for further research to develop novel tools for blocking trypanosome transmission.

  7. The use of yellow fluorescent hybrids to indicate mating in Trypanosoma brucei

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    Ferris Vanessa

    2008-02-01

    Full Text Available Abstract Background Trypanosoma brucei undergoes genetic exchange in its insect vector, the tsetse fly, by an unknown mechanism. The difficulties of working with this experimental system of genetic exchange have hampered investigation, particularly because the trypanosome life cycle stages involved cannot be cultured in vitro and therefore must be examined in the insect. Searching for small numbers of hybrid trypanosomes directly in the fly has become possible through the incorporation of fluorescent reporter genes, and we have previously carried out a successful cross using a reporter-repressor strategy. However, we could not be certain that all fluorescent trypanosomes observed in that cross were hybrids, due to mutations of the repressor leading to spontaneous fluorescence, and we have therefore developed an alternative strategy. Results To visualize the production of hybrids in the fly, parental trypanosome clones were transfected with a gene encoding Green Fluorescent Protein (GFP or Red Fluorescent Protein (RFP. Co-infection of flies with red and green fluorescent parental trypanosomes produced yellow fluorescent hybrids, which were easily visualized in the fly salivary glands. Yellow trypanosomes were not seen in midgut or proventricular samples and first appeared in the glands as epimastigotes as early as 13 days after fly infection. Cloned progeny originating from individual salivary glands had yellow, red, green or no fluorescence and were confirmed as hybrids by microsatellite, molecular karyotype and kinetoplast (mitochondrial DNA analyses. Hybrid clones showed biparental inheritance of both nuclear and kinetoplast genomes. While segregation and reassortment of the reporter genes and microsatellite alleles were consistent with Mendelian inheritance, flow cytometry measurement of DNA content revealed both diploid and polyploid trypanosomes among the hybrid progeny clones. Conclusion The strategy of using production of yellow hybrids

  8. JBP2, a SWI2/SNF2-like protein, regulates de novo telomeric DNA glycosylation in bloodstream form Trypanosoma brucei.

    Science.gov (United States)

    Kieft, Rudo; Brand, Verena; Ekanayake, Dilrukshi K; Sweeney, Kate; DiPaolo, Courtney; Reznikoff, William S; Sabatini, Robert

    2007-11-01

    Synthesis of the modified thymine base, beta-d-glucosyl-hydroxymethyluracil or J, within telomeric DNA of Trypanosoma brucei correlates with the bloodstream form specific epigenetic silencing of telomeric variant surface glycoprotein genes involved in antigenic variation. In order to analyze the function of base J in the regulation of antigenic variation, we are characterizing the regulatory mechanism of J biosynthesis. We have recently proposed a model in which chromatin remodeling by a SWI2/SNF2-like protein (JBP2) regulates the developmental and de novo site-specific localization of J synthesis within bloodstream form trypanosome DNA. Consistent with this model, we now show that JBP2 (-/-) bloodstream form trypanosomes contain five-fold less base J and are unable to stimulate de novo J synthesis in newly generated telomeric arrays. PMID:17706299

  9. Differential expression of glycosomal and mitochondrial proteins in the two major life-cycle stages of Trypanosoma brucei.

    Science.gov (United States)

    Vertommen, Didier; Van Roy, Joris; Szikora, Jean-Pierre; Rider, Mark H; Michels, Paul A M; Opperdoes, Fred R

    2008-04-01

    Label-free semi-quantitative differential three-dimensional liquid chromatography coupled to mass spectrometry (3D-LC-MS/MS) was used to compare the glycosomal and mitochondrial proteomes of the bloodstream- and insect-form of Trypanosoma brucei. The abundance of glycosomal marker proteins identified in the two life-cycle stages corresponded well with the relative importance of biochemical pathways present in the glycosomes of the two stages and the peptide spectral count ratios of selected enzymes were in good agreement with published data about their enzymatic specific activities. This approach proved extremely useful for the generation of large scale proteomics data for the comparison of different life-cycle stages. Several proteins involved in oxidative stress protection, sugar-nucleotide synthesis, purine salvage, nucleotide-monophosphate formation and purine-nucleotide cycle were identified as glycosomal proteins. PMID:18242729

  10. Crystal structures of Trypanosoma brucei oligopeptidase B broaden the paradigm of catalytic regulation in prolyl oligopeptidase family enzymes.

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    Peter Canning

    Full Text Available Oligopeptidase B cleaves after basic amino acids in peptides up to 30 residues. As a virulence factor in bacteria and trypanosomatid pathogens that is absent in higher eukaryotes, this is a promising drug target. Here we present ligand-free open state and inhibitor-bound closed state crystal structures of oligopeptidase B from Trypanosoma brucei, the causative agent of African sleeping sickness. These (and related structures show the importance of structural dynamics, governed by a fine enthalpic and entropic balance, in substrate size selectivity and catalysis. Peptides over 30 residues cannot fit the enzyme cavity, preventing the complete domain closure required for a key propeller Asp/Glu to fix the catalytic His and Arg in the catalytically competent conformation. This size exclusion mechanism protects larger peptides and proteins from degradation. Similar bacterial prolyl endopeptidase and archael acylaminoacyl peptidase structures demonstrate this mechanism is conserved among oligopeptidase family enzymes across all three domains of life.

  11. Immunospecific immunoglobulins and IL-10 as markers for Trypanosoma brucei rhodesiense late stage disease in experimentally infected vervet monkeys

    DEFF Research Database (Denmark)

    Ngotho, Maina; Kagira, J.M.; Jensen, Henrik Michael Elvang;

    2009-01-01

    OBJECTIVE: To determine the usefulness of IL-10 and immunoglobulin M (IgM) as biomarkers for staging HAT in vervet monkeys, a useful pathogenesis model for humans. METHODS: Vervet monkeys were infected with Trypanosoma brucei rhodesiense and subsequently given sub-curative and curative treatment 28...... and 140 days post-infection (dpi) respectively. Matched serum and CSF samples were obtained at regular intervals and immunospecific IgM, immunoglobulin G (IgG) and IL-10 were quantified by ELISA. RESULTS: There was no detectable immunospecific IgM and IgG in the CSF before 49 dpi. CSF IgM and Ig...... followed a pattern that mimics the progression of the disease and may present reliable and useful biomarkers of the disease stage. Due to rapid decline, serum IgM and IL-10 are, additionally, potential biomarkers of the success of chemotherapy....

  12. Crystal Structures of TbCatB and rhodesain, potential chemotherapeutic targets and major cysteine proteases of Trypanosoma brucei.

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    Iain D Kerr

    Full Text Available BACKGROUND: Trypanosoma brucei is the etiological agent of Human African Trypanosomiasis, an endemic parasitic disease of sub-Saharan Africa. TbCatB and rhodesain are the sole Clan CA papain-like cysteine proteases produced by the parasite during infection of the mammalian host and are implicated in the progression of disease. Of considerable interest is the exploration of these two enzymes as targets for cysteine protease inhibitors that are effective against T. brucei. METHODS AND FINDINGS: We have determined, by X-ray crystallography, the first reported structure of TbCatB in complex with the cathepsin B selective inhibitor CA074. In addition we report the structure of rhodesain in complex with the vinyl-sulfone K11002. CONCLUSIONS: The mature domain of our TbCat*CA074 structure contains unique features for a cathepsin B-like enzyme including an elongated N-terminus extending 16 residues past the predicted maturation cleavage site. N-terminal Edman sequencing reveals an even longer extension than is observed amongst the ordered portions of the crystal structure. The TbCat*CA074 structure confirms that the occluding loop, which is an essential part of the substrate-binding site, creates a larger prime side pocket in the active site cleft than is found in mammalian cathepsin B-small molecule structures. Our data further highlight enhanced flexibility in the occluding loop main chain and structural deviations from mammalian cathepsin B enzymes that may affect activity and inhibitor design. Comparisons with the rhodesain*K11002 structure highlight key differences that may impact the design of cysteine protease inhibitors as anti-trypanosomal drugs.

  13. The multiple roles of cyclin E1 in controlling cell cycle progression and cellular morphology of Trypanosoma brucei.

    Science.gov (United States)

    Gourguechon, Stéphane; Savich, Jason M; Wang, Ching C

    2007-05-11

    Regulation of eukaryotic cell cycle progression requires sequential activation and inactivation of cyclin-dependent kinases. Previous RNA interference (RNAi) experiments in Trypanosoma brucei indicated that cyclin E1, cdc2-related kinase (CRK)1 and CRK2 are involved in regulating G1/S transition, whereas cyclin B2 and CRK3 play a pivotal role in controlling the G2/M checkpoint. To search for potential interactions between the other cyclins and CRKs that may not have been revealed by the RNAi assays, we used the yeast two-hybrid system and an in vitro glutathione-S-transferase pulldown assay and observed interactions between cyclin E1 and CRK1, CRK2 and CRK3. Cyclins E1-E4 are homologues of yeast Pho80 cyclin. But yeast complementation assays indicated that none of them possesses a Pho80-like function. Analysis of cyclin E1+CRK1 and cyclin E1+CRK2 double knockdowns in the procyclic form of T. brucei indicated that the cells were arrested more extensively in the G1 phase beyond the cumulative effect of individual knockdowns. But BrdU incorporation was impaired significantly only in cyclin E1+CRK1-depleted cells, whereas a higher percentage of cyclin E1+CRK2 knockdown cells assumed a grossly elongated posterior end morphology. A double knockdown of cyclin E1 and CRK3 arrested cells in G2/M much more efficiently than if only CRK3 was depleted. Taken together, these data suggest multiple functions of cyclin E1: it forms a complex with CRK1 in promoting G1/S phase transition; it forms a complex with CRK2 in controlling the posterior morphogenesis during G1/S transition; and it forms a complex with CRK3 in promoting passage across the G2/M checkpoint in the trypanosome. PMID:17376478

  14. The orthologue of Sjogren's syndrome nuclear autoantigen 1 (SSNA1 in Trypanosoma brucei is an immunogenic self-assembling molecule.

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    Helen P Price

    Full Text Available Primary Sjögren's Syndrome (PSS is a highly prevalent autoimmune disease, typically manifesting as lymphocytic infiltration of the exocrine glands leading to chronically impaired lacrimal and salivary secretion. Sjögren's Syndrome nuclear autoantigen 1 (SSNA1 or NA14 is a major specific target for autoantibodies in PSS but the precise function and clinical relevance of this protein are largely unknown. Orthologues of the gene are absent from many of the commonly used model organisms but are present in Chlamyodomonas reinhardtii (in which it has been termed DIP13 and most protozoa. We report the functional characterisation of the orthologue of SSNA1 in the kinetoplastid parasite, Trypanosoma brucei. Both TbDIP13 and human SSNA1 are small coiled-coil proteins which are predicted to be remote homologues of the actin-binding protein tropomyosin. We use comparative proteomic methods to identify potential interacting partners of TbDIP13. We also show evidence that TbDIP13 is able to self-assemble into fibril-like structures both in vitro and in vivo, a property which may contribute to its immunogenicity. Endogenous TbDIP13 partially co-localises with acetylated α-tubulin in the insect procyclic stage of the parasite. However, deletion of the DIP13 gene in cultured bloodstream and procyclic stages of T. brucei has little effect on parasite growth or morphology, indicating either a degree of functional redundancy or a function in an alternative stage of the parasite life cycle.

  15. The spliceosomal snRNP core complex of Trypanosoma brucei: Cloning and functional analysis reveals seven Sm protein constituents

    Science.gov (United States)

    Palfi, Zsofia; Lücke, Stephan; Lahm, Hans-Werner; Lane, William S.; Kruft, Volker; Bragado-Nilsson, Elisabeth; Séraphin, Bertrand; Bindereif, Albrecht

    2000-01-01

    Each of the trypanosome small nuclear ribonucleoproteins (snRNPs) U2, U4/U6, and U5, as well as the spliced leader (SL) RNP, contains a core of common proteins, which we have previously identified. This core is unusual because it is not recognized by anti-Sm Abs and it associates with an Sm-related sequence in the trypanosome small nuclear RNAs (snRNAs). Using peptide sequences derived from affinity-purified U2 snRNP proteins, we have cloned cDNAs for five common proteins of 8.5, 10, 12.5, 14, and 15 kDa of Trypanosoma brucei and identified them as Sm proteins SmF (8.5 kDa), -E (10 kDa), -D1 (12.5 kDa), -G (14 kDa), and -D2 (15 kDa), respectively. Furthermore, we found the trypanosome SmB (T. brucei) and SmD3 (Trypanosoma cruzi) homologues through database searches, thus completing a set of seven canonical Sm proteins. Sequence comparisons of the trypanosome proteins revealed several deviations in highly conserved positions from the Sm consensus motif. We have identified a network of specific heterodimeric and -trimeric Sm protein interactions in vitro. These results are summarized in a model of the trypanosome Sm core, which argues for a strong conservation of the Sm particle structure. The conservation extends also to the functional level, because at least one trypanosome Sm protein, SmG, was able to specifically complement a corresponding mutation in yeast. PMID:10900267

  16. Structural characterization of CYP51 from Trypanosoma cruzi and Trypanosoma brucei bound to the antifungal drugs posaconazole and fluconazole.

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    Chiung-Kuang Chen

    Full Text Available BACKGROUND: Chagas Disease is the leading cause of heart failure in Latin America. Current drug therapy is limited by issues of both efficacy and severe side effects. Trypansoma cruzi, the protozoan agent of Chagas Disease, is closely related to two other major global pathogens, Leishmania spp., responsible for leishmaniasis, and Trypansoma brucei, the causative agent of African Sleeping Sickness. Both T. cruzi and Leishmania parasites have an essential requirement for ergosterol, and are thus vulnerable to inhibitors of sterol 14alpha-demethylase (CYP51, which catalyzes the conversion of lanosterol to ergosterol. Clinically employed anti-fungal azoles inhibit ergosterol biosynthesis in fungi, and specific azoles are also effective against both Trypanosoma and Leishmania parasites. However, modification of azoles to enhance efficacy and circumvent potential drug resistance has been problematic for both parasitic and fungal infections due to the lack of structural insights into drug binding. METHODOLOGY/PRINCIPAL FINDINGS: We have determined the crystal structures for CYP51 from T. cruzi (resolutions of 2.35 A and 2.27 A, and from the related pathogen T. brucei (resolutions of 2.7 A and 2.6 A, co-crystallized with the antifungal drugs fluconazole and posaconazole. Remarkably, both drugs adopt multiple conformations when binding the target. The fluconazole 2,4-difluorophenyl ring flips 180 degrees depending on the H-bonding interactions with the BC-loop. The terminus of the long functional tail group of posaconazole is bound loosely in the mouth of the hydrophobic substrate binding tunnel, suggesting that the major contribution of the tail to drug efficacy is for pharmacokinetics rather than in interactions with the target. CONCLUSIONS/SIGNIFICANCE: The structures provide new insights into binding of azoles to CYP51 and mechanisms of potential drug resistance. Our studies define in structural detail the CYP51 therapeutic target in T. cruzi, and

  17. Characterization of 2,4-Diamino-6-oxo-1,6-dihydropyrimidin-5-yl Ureido Based Inhibitors of Trypanosoma brucei FolD and Testing for Antiparasitic Activity.

    Science.gov (United States)

    Eadsforth, Thomas C; Pinto, Andrea; Luciani, Rosaria; Tamborini, Lucia; Cullia, Gregorio; De Micheli, Carlo; Marinelli, Luciana; Cosconati, Sandro; Novellino, Ettore; Lo Presti, Leonardo; Cordeiro da Silva, Anabela; Conti, Paola; Hunter, William N; Costi, Maria P

    2015-10-22

    The bifunctional enzyme N(5),N(10)-methylenetetrahydrofolate dehydrogenase/cyclo hydrolase (FolD) is essential for growth in Trypanosomatidae. We sought to develop inhibitors of Trypanosoma brucei FolD (TbFolD) as potential antiparasitic agents. Compound 2 was synthesized, and the molecular structure was unequivocally assigned through X-ray crystallography of the intermediate compound 3. Compound 2 showed an IC50 of 2.2 μM, against TbFolD and displayed antiparasitic activity against T. brucei (IC50 49 μM). Using compound 2, we were able to obtain the first X-ray structure of TbFolD in the presence of NADP(+) and the inhibitor, which then guided the rational design of a new series of potent TbFolD inhibitors. PMID:26322631

  18. Evaluation of the In Vitro Efficacy of Artemisia annua, Rumex abyssinicus, and Catha edulis Forsk Extracts in Cancer and Trypanosoma brucei Cells

    OpenAIRE

    Netsanet Worku; Andualem Mossie; August Stich; Arwid Daugschies; Susanne Trettner; Hemdan, Nasr Y. A.; Gerd Birkenmeier

    2013-01-01

    The current drugs against sleeping sickness are derived from cancer chemotherapeutic approaches. Herein, we aimed at evaluating the in vitro effect of alcoholic extracts of Artemisia annua (AMR), Rumex abyssinicus (RMA), and Catha edulis Forsk (CEF) on proliferation/viability of 1321N1 astrocytoma, MCF-7 breast cancer, THP-1 leukemia, and LNCaP, Du-145, and PC-3 prostate cancer cells and on Trypanosoma brucei cells. Proliferation of tumor cells was evaluated by WST-1 assay and viability/behav...

  19. Effect of experimental single Ancylostoma caninum and mixed infections of Trypanosoma brucei and Trypanosoma congolense on the humoural immune response to anti-rabies vaccination in dogs

    Institute of Scientific and Technical Information of China (English)

    Nwoha Rosemary Ijeoma Ogechi; Anene Boniface Maduka

    2015-01-01

    Objective:To determine the effect of Ancylostoma caninum (A. caninum) and trypanosome parasites on the immune response to vaccination in dogs in endemic environments. Methods:Sixteen dogs for the experiment were grouped into 4 of 4 members each. Group I was the uninfected control one, and GPII was infected with A. caninum; GPIII was infected with A. caninum/Trypanosoma congolense (T. congolense), and GPIV was infected with Trypanosoma brucei (T. brucei)/A. caninum. The dogs were first vaccinated with antirabies vaccine before infecting GPII, GPIII and GPIV with A. caninum which were done 4 weeks after vaccination. By 2-week post-vaccination, trypanosome parasites were superimposed on both GPIII and GPIV. A secondary vaccination was given to GPI, GPII, GPIII, and GPIV by Week 12 of the experiment (4 weeks post treatment). Results:The prepatent period was (3.00 ± 1.40) days, in the conjunct infection of T. brucei/A. caninum. It was (9.00 ± 1.10) days, in conjunct T. congolense/A. caninum. The prepatent period of A. caninum was (14.0 ± 2.0) days in the single A. caninum group and (13.0 ± 1.0) days in the conjunct trypanosome/A. caninum. At the 1st week after vaccination, the antibody titer in all the vaccinated groups (GPI, GPII, GPIII, and GPIV) significantly increased (P Conclusions:It was therefore concluded that A. caninum, T. brucei and T. congolense induced immunosuppression in antirabies vaccination in dogs.

  20. A pseudouridylation switch in rRNA is implicated in ribosome function during the life cycle of Trypanosoma brucei.

    Science.gov (United States)

    Chikne, Vaibhav; Doniger, Tirza; Rajan, K Shanmugha; Bartok, Osnat; Eliaz, Dror; Cohen-Chalamish, Smadar; Tschudi, Christian; Unger, Ron; Hashem, Yaser; Kadener, Sebastian; Michaeli, Shulamit

    2016-01-01

    The protozoan parasite Trypanosoma brucei, which causes devastating diseases in humans and animals in sub-Saharan Africa, undergoes a complex life cycle between the mammalian host and the blood-feeding tsetse fly vector. However, little is known about how the parasite performs most molecular functions in such different environments. Here, we provide evidence for the intriguing possibility that pseudouridylation of rRNA plays an important role in the capacity of the parasite to transit between the insect midgut and the mammalian bloodstream. Briefly, we mapped pseudouridines (Ψ) on rRNA by Ψ-seq in procyclic form (PCF) and bloodstream form (BSF) trypanosomes. We detected 68 Ψs on rRNA, which are guided by H/ACA small nucleolar RNAs (snoRNA). The small RNome of both life cycle stages was determined by HiSeq and 83 H/ACAs were identified. We observed an elevation of 21 Ψs modifications in BSF as a result of increased levels of the guiding snoRNAs. Overexpression of snoRNAs guiding modification on H69 provided a slight growth advantage to PCF parasites at 30 °C. Interestingly, these modifications are predicted to significantly alter the secondary structure of the large subunit (LSU) rRNA suggesting that hypermodified positions may contribute to the adaption of ribosome function during cycling between the two hosts. PMID:27142987

  1. GMP synthase is essential for viability and infectivity of Trypanosoma brucei despite a redundant purine salvage pathway.

    Science.gov (United States)

    Li, Qiong; Leija, Christopher; Rijo-Ferreira, Filipa; Chen, Jun; Cestari, Igor; Stuart, Kenneth; Tu, Benjamin P; Phillips, Margaret A

    2015-09-01

    The causative agent of human African trypanosomiasis, Trypanosoma brucei, lacks de novo purine biosynthesis and depends on purine salvage from the host. The purine salvage pathway is redundant and contains two routes to guanosine-5'-monophosphate (GMP) formation: conversion from xanthosine-5'-monophosphate (XMP) by GMP synthase (GMPS) or direct salvage of guanine by hypoxanthine-guanine phosphoribosyltransferase (HGPRT). We show recombinant T. brucei GMPS efficiently catalyzes GMP formation. Genetic knockout of GMPS in bloodstream parasites led to depletion of guanine nucleotide pools and was lethal. Growth of gmps null cells was only rescued by supraphysiological guanine concentrations (100 μM) or by expression of an extrachromosomal copy of GMPS. Hypoxanthine was a competitive inhibitor of guanine rescue, consistent with a common uptake/metabolic conversion mechanism. In mice, gmps null parasites were unable to establish an infection demonstrating that GMPS is essential for virulence and that plasma guanine is insufficient to support parasite purine requirements. These data validate GMPS as a potential therapeutic target for treatment of human African trypanosomiasis. The ability to strategically inhibit key metabolic enzymes in the purine pathway unexpectedly bypasses its functional redundancy by exploiting both the nature of pathway flux and the limited nutrient environment of the parasite's extracellular niche. PMID:26043892

  2. Probing the metabolic network in bloodstream-form Trypanosoma brucei using untargeted metabolomics with stable isotope labelled glucose.

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    Darren J Creek

    2015-03-01

    Full Text Available Metabolomics coupled with heavy-atom isotope-labelled glucose has been used to probe the metabolic pathways active in cultured bloodstream form trypomastigotes of Trypanosoma brucei, a parasite responsible for human African trypanosomiasis. Glucose enters many branches of metabolism beyond glycolysis, which has been widely held to be the sole route of glucose metabolism. Whilst pyruvate is the major end-product of glucose catabolism, its transamination product, alanine, is also produced in significant quantities. The oxidative branch of the pentose phosphate pathway is operative, although the non-oxidative branch is not. Ribose 5-phosphate generated through this pathway distributes widely into nucleotide synthesis and other branches of metabolism. Acetate, derived from glucose, is found associated with a range of acetylated amino acids and, to a lesser extent, fatty acids; while labelled glycerol is found in many glycerophospholipids. Glucose also enters inositol and several sugar nucleotides that serve as precursors to macromolecule biosynthesis. Although a Krebs cycle is not operative, malate, fumarate and succinate, primarily labelled in three carbons, were present, indicating an origin from phosphoenolpyruvate via oxaloacetate. Interestingly, the enzyme responsible for conversion of phosphoenolpyruvate to oxaloacetate, phosphoenolpyruvate carboxykinase, was shown to be essential to the bloodstream form trypanosomes, as demonstrated by the lethal phenotype induced by RNAi-mediated downregulation of its expression. In addition, glucose derivatives enter pyrimidine biosynthesis via oxaloacetate as a precursor to aspartate and orotate.

  3. A global comparison of the human and T. brucei degradomes gives insights about possible parasite drug targets.

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    Susan T Mashiyama

    Full Text Available We performed a genome-level computational study of sequence and structure similarity, the latter using crystal structures and models, of the proteases of Homo sapiens and the human parasite Trypanosoma brucei. Using sequence and structure similarity networks to summarize the results, we constructed global views that show visually the relative abundance and variety of proteases in the degradome landscapes of these two species, and provide insights into evolutionary relationships between proteases. The results also indicate how broadly these sequence sets are covered by three-dimensional structures. These views facilitate cross-species comparisons and offer clues for drug design from knowledge about the sequences and structures of potential drug targets and their homologs. Two protease groups ("M32" and "C51" that are very different in sequence from human proteases are examined in structural detail, illustrating the application of this global approach in mining new pathogen genomes for potential drug targets. Based on our analyses, a human ACE2 inhibitor was selected for experimental testing on one of these parasite proteases, TbM32, and was shown to inhibit it. These sequence and structure data, along with interactive versions of the protein similarity networks generated in this study, are available at http://babbittlab.ucsf.edu/resources.html.

  4. A pseudouridylation switch in rRNA is implicated in ribosome function during the life cycle of Trypanosoma brucei.

    Science.gov (United States)

    Chikne, Vaibhav; Doniger, Tirza; Rajan, K Shanmugha; Bartok, Osnat; Eliaz, Dror; Cohen-Chalamish, Smadar; Tschudi, Christian; Unger, Ron; Hashem, Yaser; Kadener, Sebastian; Michaeli, Shulamit

    2016-01-01

    The protozoan parasite Trypanosoma brucei, which causes devastating diseases in humans and animals in sub-Saharan Africa, undergoes a complex life cycle between the mammalian host and the blood-feeding tsetse fly vector. However, little is known about how the parasite performs most molecular functions in such different environments. Here, we provide evidence for the intriguing possibility that pseudouridylation of rRNA plays an important role in the capacity of the parasite to transit between the insect midgut and the mammalian bloodstream. Briefly, we mapped pseudouridines (Ψ) on rRNA by Ψ-seq in procyclic form (PCF) and bloodstream form (BSF) trypanosomes. We detected 68 Ψs on rRNA, which are guided by H/ACA small nucleolar RNAs (snoRNA). The small RNome of both life cycle stages was determined by HiSeq and 83 H/ACAs were identified. We observed an elevation of 21 Ψs modifications in BSF as a result of increased levels of the guiding snoRNAs. Overexpression of snoRNAs guiding modification on H69 provided a slight growth advantage to PCF parasites at 30 °C. Interestingly, these modifications are predicted to significantly alter the secondary structure of the large subunit (LSU) rRNA suggesting that hypermodified positions may contribute to the adaption of ribosome function during cycling between the two hosts.

  5. Comparative pathogenicity of Trypanosoma brucei rhodesiense strains in Swiss white mice and Mastomys natalensis rats.

    Science.gov (United States)

    Muchiri, Margaret Wanjiku; Ndung'u, Kariuki; Kibugu, James Karuku; Thuita, John Kibuthu; Gitonga, Purity Kaari; Ngae, Geoffrey Njuguna; Mdachi, Raymond Ellie; Kagira, John Maina

    2015-10-01

    We evaluated Mastomys natelensis rat as an animal model for Rhodesian sleeping sickness. Parasitaemia, clinical and pathological characteristics induced by T. b. rhodesiense isolates, KETRI 3439, 3622 and 3637 were compared in Mastomys rats and Swiss white mice. Each isolate was intra-peritonially injected in mice and rat groups (n=12) at 1×10(4) trypanosomes/0.2mL. Pre-patent period (PP) range for KETRI 3439 and KETRI 3622-groups was 3-6 days for mice and 4-5 days for rats while for KETRI 3637-infected mice and rats was 5-9 and 4-12 days, respectively. Pairwise comparison between PP of mice and rats separately infected with either isolate showed no significant difference (p>0.05). The PP's of KETRI 3637-infected mice were significantly (p>0.01) longer than those infected with KETRI 3439 or KETRI 3622, a trend also observed in rats. The second parasitaemic wave was more prominent in mice. Clinical signs included body weakness, dyspnoea, peri-orbital oedema and extreme emaciation which were more common in rats. Survival time for KETRI 3439 and 3622-infected groups was significantly (ppneumonia, enteritis with moderate splenomegaly and lymphadenopathy. KETRI 3637-infected rats had the most severe lesions characterized by prominent splenomegaly, lymphadenopathy, hepatomegaly, enlarged adrenal glands, organ congestion, generalized oedemas, gastroenteritis, pneumonia and brain congestion. KETRI 3637-infected Mastomys is a suitable model for studying pathophysiology of HAT. PMID:26099681

  6. Simultaneous depletion of Atm and Mdl rebalances cytosolic Fe-S cluster assembly but not heme import into the mitochondrion of Trypanosoma brucei.

    Science.gov (United States)

    Horáková, Eva; Changmai, Piya; Paris, Zdeněk; Salmon, Didier; Lukeš, Julius

    2015-11-01

    ABC transporter mitochondrial 1 (Atm1) and multidrug resistance-like 1 (Mdl) are mitochondrial ABC transporters. Although Atm1 was recently suggested to transport different forms of glutathione from the mitochondrion, which are used for iron-sulfur (Fe-S) cluster maturation in the cytosol, the function of Mdl remains elusive. In Trypanosoma brucei, we identified one homolog of each of these genes, TbAtm and TbMdl, which were downregulated either separately or simultaneously using RNA interference. Individual depletion of TbAtm and TbMdl led to limited growth defects. In cells downregulated for TbAtm, the enzymatic activities of the Fe-S cluster proteins aconitase and fumarase significantly decreased in the cytosol but not in the mitochondrion. Downregulation of TbMdl did not cause any change in activities of the Fe-S proteins. Unexpectedly, the simultaneous downregulation of TbAtm and TbMdl did not result in any growth defect, nor were the Fe-S cluster protein activities altered in either the cytosolic or mitochondrial compartments. Additionally, TbAtm and TbMdl were able to partially restore the growth of the Saccharomyces cerevisiae Δatm1 and Δmdl2 null mutants, respectively. Because T. brucei completely lost the heme b biosynthesis pathway, this cofactor has to be obtained from the host. Based on our results, TbMdl is a candidate for mitochondrial import of heme b, which was markedly decreased in both TbMdl and TbAtm + TbMdl knockdowns. Moreover, the levels of heme a were strongly decreased in the same knockdowns, suggesting that TbMdl plays a key role in heme a biosynthesis, thus affecting the overall heme homeostasis in T. brucei. PMID:26277108

  7. Histone H3 Variant Regulates RNA Polymerase II Transcription Termination and Dual Strand Transcription of siRNA Loci in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    David Reynolds

    2016-01-01

    Full Text Available Base J, β-D-glucosyl-hydroxymethyluracil, is a chromatin modification of thymine in the nuclear DNA of flagellated protozoa of the order Kinetoplastida. In Trypanosoma brucei, J is enriched, along with histone H3 variant (H3.V, at sites involved in RNA Polymerase (RNAP II termination and telomeric sites involved in regulating variant surface glycoprotein gene (VSG transcription by RNAP I. Reduction of J in T. brucei indicated a role of J in the regulation of RNAP II termination, where the loss of J at specific sites within polycistronic gene clusters led to read-through transcription and increased expression of downstream genes. We now demonstrate that the loss of H3.V leads to similar defects in RNAP II termination within gene clusters and increased expression of downstream genes. Gene derepression is intensified upon the subsequent loss of J in the H3.V knockout. mRNA-seq indicates gene derepression includes VSG genes within the silent RNAP I transcribed telomeric gene clusters, suggesting an important role for H3.V in telomeric gene repression and antigenic variation. Furthermore, the loss of H3.V at regions of overlapping transcription at the end of convergent gene clusters leads to increased nascent RNA and siRNA production. Our results suggest base J and H3.V can act independently as well as synergistically to regulate transcription termination and expression of coding and non-coding RNAs in T. brucei, depending on chromatin context (and transcribing polymerase. As such these studies provide the first direct evidence for histone H3.V negatively influencing transcription elongation to promote termination.

  8. Functional and structural insights revealed by molecular dynamics simulations of an essential RNA editing ligase in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Rommie E Amaro

    Full Text Available RNA editing ligase 1 (TbREL1 is required for the survival of both the insect and bloodstream forms of Trypanosoma brucei, the parasite responsible for the devastating tropical disease African sleeping sickness. The type of RNA editing that TbREL1 is involved in is unique to the trypanosomes, and no close human homolog is known to exist. In addition, the high-resolution crystal structure revealed several unique features of the active site, making this enzyme a promising target for structure-based drug design. In this work, two 20 ns atomistic molecular dynamics (MD simulations are employed to investigate the dynamics of TbREL1, both with and without the ATP substrate present. The flexibility of the active site, dynamics of conserved residues and crystallized water molecules, and the interactions between TbREL1 and the ATP substrate are investigated and discussed in the context of TbREL1's function. Differences in local and global motion upon ATP binding suggest that two peripheral loops, unique to the trypanosomes, may be involved in interdomain signaling events. Notably, a significant structural rearrangement of the enzyme's active site occurs during the apo simulations, opening an additional cavity adjacent to the ATP binding site that could be exploited in the development of effective inhibitors directed against this protozoan parasite. Finally, ensemble averaged electrostatics calculations over the MD simulations reveal a novel putative RNA binding site, a discovery that has previously eluded scientists. Ultimately, we use the insights gained through the MD simulations to make several predictions and recommendations, which we anticipate will help direct future experimental studies and structure-based drug discovery efforts against this vital enzyme.

  9. Crystal Structures of Trypanosoma brucei Sterol 14[alpha]-Demethylase and Implications for Selective Treatment of Human Infections

    Energy Technology Data Exchange (ETDEWEB)

    Lepesheva, Galina I.; Park, Hee-Won; Hargrove, Tatiana Y.; Vanhollebeke, Benoit; Wawrzak, Zdzislaw; Harp, Joel M.; Sundaramoorthy, Munirathinam; Nes, W. David; Pays, Etienne; Chaudhuri, Minu; Villalta, Fernando; Waterman, Michael R. (ULdB); (Vanderbilt); (TTU); (Toronto); (NWU); (Meharry)

    2010-01-25

    Sterol 14{alpha}-demethylase (14DM, the CYP51 family of cytochrome P450) is an essential enzyme in sterol biosynthesis in eukaryotes. It serves as a major drug target for fungal diseases and can potentially become a target for treatment of human infections with protozoa. Here we present 1.9 {angstrom} resolution crystal structures of 14DM from the protozoan pathogen Trypanosoma brucei, ligand-free and complexed with a strong chemically selected inhibitor N-1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl-4-(5-phenyl-1,3,4-oxadi-azol-2-yl)benzamide that we previously found to produce potent antiparasitic effects in Trypanosomatidae. This is the first structure of a eukaryotic microsomal 14DM that acts on sterol biosynthesis, and it differs profoundly from that of the water-soluble CYP51 family member from Mycobacterium tuberculosis, both in organization of the active site cavity and in the substrate access channel location. Inhibitor binding does not cause large scale conformational rearrangements, yet induces unanticipated local alterations in the active site, including formation of a hydrogen bond network that connects, via the inhibitor amide group fragment, two remote functionally essential protein segments and alters the heme environment. The inhibitor binding mode provides a possible explanation for both its functionally irreversible effect on the enzyme activity and its selectivity toward the 14DM from human pathogens versus the human 14DM ortholog. The structures shed new light on 14DM functional conservation and open an excellent opportunity for directed design of novel antiparasitic drugs.

  10. A Novel Basal Body Protein That Is a Polo-like Kinase Substrate Is Required for Basal Body Segregation and Flagellum Adhesion in Trypanosoma brucei.

    Science.gov (United States)

    Hu, Huiqing; Zhou, Qing; Li, Ziyin

    2015-10-01

    The Polo-like kinase (PLK) in Trypanosoma brucei plays multiple roles in basal body segregation, flagellum attachment, and cytokinesis. However, the mechanistic role of TbPLK remains elusive, mainly because most of its substrates are not known. Here, we report a new substrate of TbPLK, SPBB1, and its essential roles in T. brucei. SPBB1 was identified through yeast two-hybrid screening with the kinase-dead TbPLK as the bait. It interacts with TbPLK in vitro and in vivo, and is phosphorylated by TbPLK in vitro. SPBB1 localizes to both the mature basal body and the probasal body throughout the cell cycle, and co-localizes with TbPLK at the basal body during early cell cycle stages. RNAi against SPBB1 in procyclic trypanosomes inhibited basal body segregation, disrupted the new flagellum attachment zone filament, detached the new flagellum, and caused defective cytokinesis. Moreover, RNAi of SPBB1 confined TbPLK at the basal body and the bilobe structure, resulting in constitutive phosphorylation of TbCentrin2 at the bilobe. Altogether, these results identified a basal body protein as a TbPLK substrate and its essential role in promoting basal body segregation and flagellum attachment zone filament assembly for flagellum adhesion and cytokinesis initiation.

  11. Nucleolar accumulation of RNA binding proteins induced by Actinomycin D is functional in Trypanosoma cruzi and Leishmania mexicana but not in T. brucei.

    Directory of Open Access Journals (Sweden)

    Ezequiel Názer

    Full Text Available We have recently shown in T. cruzi that a group of RNA Binding Proteins (RBPs, involved in mRNA metabolism, are accumulated into the nucleolus in response to Actinomycin D (ActD treatment. In this work, we have extended our analysis to other members of the trypanosomatid lineage. In agreement with our previous study, the mechanism seems to be conserved in L. mexicana, since both endogenous RBPs and a transgenic RBP were relocalized to the nucleolus in parasites exposed to ActD. In contrast, in T. brucei, neither endogenous RBPs (TbRRM1 and TbPABP2 nor a transgenic RBP from T. cruzi were accumulated into the nucleolus under such treatment. Interestingly, when a transgenic TbRRM1 was expressed in T. cruzi and the parasites exposed to ActD, TbRRM1 relocated to the nucleolus, suggesting that it contains the necessary sequence elements to be targeted to the nucleolus. Together, both experiments demonstrate that the mechanism behind nucleolar localization of RBPs, which is present in T. cruzi and L. mexicana, is not functional in T. brucei, suggesting that it has been lost or retained differentially during the evolution of the trypanosomatid lineage.

  12. Dynein Light Chain LC8 Is Required for RNA Polymerase I-Mediated Transcription in Trypanosoma brucei, Facilitating Assembly and Promoter Binding of Class I Transcription Factor A.

    Science.gov (United States)

    Kirkham, Justin K; Park, Sung Hee; Nguyen, Tu N; Lee, Ju Huck; Günzl, Arthur

    2016-01-01

    Dynein light chain LC8 is highly conserved among eukaryotes and has both dynein-dependent and dynein-independent functions. Interestingly, LC8 was identified as a subunit of the class I transcription factor A (CITFA), which is essential for transcription by RNA polymerase I (Pol I) in the parasite Trypanosoma brucei. Given that LC8 has never been identified with a basal transcription factor and that T. brucei relies on RNA Pol I for expressing the variant surface glycoprotein (VSG), the key protein in antigenic variation, we investigated the CITFA-specific role of LC8. Depletion of LC8 from mammalian-infective bloodstream trypanosomes affected cell cycle progression, reduced the abundances of rRNA and VSG mRNA, and resulted in rapid cell death. Sedimentation analysis, coimmunoprecipitation of recombinant proteins, and bioinformatic analysis revealed an LC8 binding site near the N terminus of the subunit CITFA2. Mutation of this site prevented the formation of a CITFA2-LC8 heterotetramer and, in vivo, was lethal, affecting assembly of a functional CITFA complex. Gel shift assays and UV cross-linking experiments identified CITFA2 as a promoter-binding CITFA subunit. Accordingly, silencing of LC8 or CITFA2 resulted in a loss of CITFA from RNA Pol I promoters. Hence, we discovered an LC8 interaction that, unprecedentedly, has a basal function in transcription.

  13. Lipid-drug conjugate nanoparticles of the hydrophilic drug diminazene-cytotoxicity testing and mouse serum adsorption

    NARCIS (Netherlands)

    Olbrich, C.; Gessner, A.; Schroder, W.; Kayser, Oliver; Muller, R.H.

    2004-01-01

    Sleeping sickness is a widely distributed disease in great parts of Africa. It is caused by Trypanosoma brucei gambiense and rhodiense, transmitted by the Tse-Tse fly. After a hemolymphatic stage, the parasites enter the central nervous system where they cannot be reached by hydrophilic drugs. To po

  14. Human African Trypanosomiasis Transmission, Kinshasa, Democratic Republic of Congo

    Science.gov (United States)

    Diabakana, Philemon Mansinsa; Mesu, Victor Kande Betu Ku; Manzambi, Emile Zola; Ollivier, Gaelle; Asonganyi, Tazoacha; Cuny, Gerard; Grébaut, Pascal

    2006-01-01

    To investigate the epidemiology of human African trypanosomiasis (sleeping sickness) in Kinshasa, Democratic Republic of Congo, 2 entomologic surveys were conducted in 2005. Trypanosoma brucei gambiense and human-blood meals were found in tsetse fly midguts, which suggested active disease transmission. Vector control should be used to improve human African trypanosomiasis control efforts. PMID:17326955

  15. Quantitative Mass Spectrometry-Based Analysis of β-D-Glucosyl-5-Hydroxymethyluracil in Genomic DNA of Trypanosoma brucei

    Science.gov (United States)

    Liu, Shuo; Ji, Debin; Cliffe, Laura; Sabatini, Robert; Wang, Yinsheng

    2014-10-01

    β-D-glucosyl-5-hydroxymethyluracil (base J) is a hyper-modified nucleobase found in the nuclear DNA of kinetoplastid parasites. With replacement of a fraction of thymine in DNA, J is localized primarily in telomeric regions of all organisms carrying this modified base. The biosynthesis of J occurs in two putative steps: first, a specific thymine in DNA is recognized and converted into 5-hydroxymethyluracil (5-HmU) by J-binding proteins (JBP1 and JBP2); a glucosyl transferase (GT) subsequently glucosylates the 5-HmU to yield J. Although several recent studies revealed the roles of internal J in regulating transcription in kinetoplastids, functions of telomeric J and proteins involved in J synthesis remain elusive. Assessing the functions of base J and understanding fully its biosynthesis necessitate the measurement of its level in cells and organisms. In this study, we reported a reversed-phase HPLC coupled with tandem mass spectrometry (LC-MS/MS) method, together with the use of a surrogate internal standard (β-D-glucosyl-5-hydroxymethyl-2'-deoxycytidine, 5-gHmdC), for the accurate detection of β-D-glucosyl-5-hydroxymethyl-2'-deoxyuridine (dJ) in Trypanosoma brucei DNA. For comparison, we also measured the level of the precursor for dJ synthesis [i.e. 5-hydroxymethyl-2'-deoxyuridine (5-HmdU)]. We found that base J was not detectable in the JBP-null cells whereas it replaced approximately 0.5% thymine in wild-type cells, which was accompanied with a markedly decreased level of 5-HmdU in JBP1/JBP2-null strain relative to the wild-type strain. These results provided direct evidence supporting that JBP proteins play an important role in oxidizing thymidine to form 5-HmdU, which facilitated the generation of dJ. This is the first report about the application of LC-MS/MS for the quantification of base J. The analytical method built a solid foundation for dissecting the molecular mechanisms of J biosynthesis and assessing the biological functions of base J in the

  16. A core MRB1 complex component is indispensable for RNA editing in insect and human infective stages of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Michelle L Ammerman

    Full Text Available Uridine insertion/deletion RNA editing is a unique and vital process in kinetoplastids, required for creation of translatable open reading frames in most mitochondrially-encoded RNAs. Emerging as a key player in this process is the mitochondrial RNA binding 1 (MRB1 complex. MRB1 comprises an RNA-independent core complex of at least six proteins, including the GAP1/2 guide RNA (gRNA binding proteins. The core interacts in an RNA-enhanced or -dependent manner with imprecisely defined TbRGG2 subcomplexes, Armadillo protein MRB10130, and additional factors that comprise the dynamic MRB1 complex. Towards understanding MRB1 complex function in RNA editing, we present here functional characterization of the pentein domain-containing MRB1 core protein, MRB11870. Inducible RNAi studies demonstrate that MRB11870 is essential for proliferation of both insect vector and human infective stage T. brucei. MRB11870 ablation causes a massive defect in RNA editing, affecting both pan-edited and minimally edited mRNAs, but does not substantially affect mitochondrial RNA stability or processing of precursor transcripts. The editing defect in MRB1-depleted cells occurs at the initiation stage of editing, as pre-edited mRNAs accumulate. However, the gRNAs that direct editing remain abundant in the knockdown cells. To examine the contribution of MRB11870 to MRB1 macromolecular interactions, we tagged core complexes and analyzed their composition and associated proteins in the presence and absence of MRB11870. These studies demonstrated that MRB11870 is essential for association of GAP1/2 with the core, as well as for interaction of the core with other proteins and subcomplexes. Together, these data support a model in which the MRB1 core mediates functional interaction of gRNAs with the editing machinery, having GAP1/2 as its gRNA binding constituents. MRB11870 is a critical component of the core, essential for its structure and function.

  17. 3-(3-amino-3-carboxypropyl)-5,6-Dihydrouridine is one of two novel post-transcriptional modifications in tRNALys(UUU) from Trypanosoma brucei

    DEFF Research Database (Denmark)

    Krog, Jesper Schak; Español, Yaiza; Giessing, Anders M B;

    2011-01-01

    the entire analysis. We identified modifications on 12 nucleosides in tRNA(Lys) (UUU), where U47 exhibited a novel modification, 3-(3-amino-3-carboxypropyl)-5,6-dihydrouridine, based on identical chromatographic retention and MS fragmentation as the synthetic nucleoside. A37 was observed in two versions....... Furthermore, the tRNA has to be investigated with single-nucleotide resolution in order to ensure complete mapping of all modifications. In the present work, we characterized tRNA(Lys) (UUU) from Trypanosoma brucei, and provide a complete overview of its post-transcriptional modifications. The first step...... of the unmodified tRNA revealed the modified residues. The modifications were further characterized at the nucleoside level by chromatographic retention time and fragmentation pattern upon higher-order tandem MS. Phylogenetic comparison with modifications in tRNA(Lys) from other organisms was used through...

  18. Characterization of a Novel Class I Transcription Factor A (CITFA) Subunit That Is Indispensable for Transcription by the Multifunctional RNA Polymerase I of Trypanosoma brucei

    KAUST Repository

    Nguyen, T. N.

    2012-10-26

    Trypanosoma brucei is the only organism known to have evolved a multifunctional RNA polymerase I (pol I) system that is used to express the parasite\\'s ribosomal RNAs, as well as its major cell surface antigens, namely, the variant surface glycoprotein (VSG) and procyclin, which are vital for establishing successful infections in the mammalian host and the tsetse vector, respectively. Thus far, biochemical analyses of the T. brucei RNA pol I transcription machinery have elucidated the subunit structure of the enzyme and identified the class I transcription factor A (CITFA). CITFA binds to RNA pol I promoters, and its CITFA-2 subunit was shown to be absolutely essential for RNA pol I transcription in the parasite. Tandem affinity purification (TAP) of CITFA revealed the subunits CITFA-1 to -6, which are conserved only among kinetoplastid organisms, plus the dynein light chain DYNLL1. Here, by tagging CITFA-6 instead of CITFA-2, a complex was purified that contained all known CITFA subunits, as well as a novel proline-rich protein. Functional studies carried out in vivo and in vitro, as well as a colocalization study, unequivocally demonstrated that this protein is a bona fide CITFA subunit, essential for parasite viability and indispensable for RNA pol I transcription of ribosomal gene units and the active VSG expression site in the mammalian-infective life cycle stage of the parasite. Interestingly, CITFA-7 function appears to be species specific, because expression of an RNA interference (RNAi)-resistant CITFA-7 transgene from Trypanosoma cruzi could not rescue the lethal phenotype of silencing endogenous CITFA-7.

  19. Structures of Trypanosoma brucei methionyl-tRNA synthetase with urea-based inhibitors provide guidance for drug design against sleeping sickness.

    Directory of Open Access Journals (Sweden)

    Cho Yeow Koh

    2014-04-01

    Full Text Available Methionyl-tRNA synthetase of Trypanosoma brucei (TbMetRS is an important target in the development of new antitrypanosomal drugs. The enzyme is essential, highly flexible and displaying a large degree of changes in protein domains and binding pockets in the presence of substrate, product and inhibitors. Targeting this protein will benefit from a profound understanding of how its structure adapts to ligand binding. A series of urea-based inhibitors (UBIs has been developed with IC50 values as low as 19 nM against the enzyme. The UBIs were shown to be orally available and permeable through the blood-brain barrier, and are therefore candidates for development of drugs for the treatment of late stage human African trypanosomiasis. Here, we expand the structural diversity of inhibitors from the previously reported collection and tested for their inhibitory effect on TbMetRS and on the growth of T. brucei cells. The binding modes and binding pockets of 14 UBIs are revealed by determination of their crystal structures in complex with TbMetRS at resolutions between 2.2 Å to 2.9 Å. The structures show binding of the UBIs through conformational selection, including occupancy of the enlarged methionine pocket and the auxiliary pocket. General principles underlying the affinity of UBIs for TbMetRS are derived from these structures, in particular the optimum way to fill the two binding pockets. The conserved auxiliary pocket might play a role in binding tRNA. In addition, a crystal structure of a ternary TbMetRS•inhibitor•AMPPCP complex indicates that the UBIs are not competing with ATP for binding, instead are interacting with ATP through hydrogen bond. This suggests a possibility that a general 'ATP-engaging' binding mode can be utilized for the design and development of inhibitors targeting tRNA synthetases of other disease-causing pathogen.

  20. Cytosolic NADPH homeostasis in glucose-starved procyclic Trypanosoma brucei relies on malic enzyme and the pentose phosphate pathway fed by gluconeogenic flux.

    Science.gov (United States)

    Allmann, Stefan; Morand, Pauline; Ebikeme, Charles; Gales, Lara; Biran, Marc; Hubert, Jane; Brennand, Ana; Mazet, Muriel; Franconi, Jean-Michel; Michels, Paul A M; Portais, Jean-Charles; Boshart, Michael; Bringaud, Frédéric

    2013-06-21

    All living organisms depend on NADPH production to feed essential biosyntheses and for oxidative stress defense. Protozoan parasites such as the sleeping sickness pathogen Trypanosoma brucei adapt to different host environments, carbon sources, and oxidative stresses during their infectious life cycle. The procyclic stage develops in the midgut of the tsetse insect vector, where they rely on proline as carbon source, although they prefer glucose when grown in rich media. Here, we investigate the flexible and carbon source-dependent use of NADPH synthesis pathways in the cytosol of the procyclic stage. The T. brucei genome encodes two cytosolic NADPH-producing pathways, the pentose phosphate pathway (PPP) and the NADP-dependent malic enzyme (MEc). Reverse genetic blocking of those pathways and a specific inhibitor (dehydroepiandrosterone) of glucose-6-phosphate dehydrogenase together established redundancy with respect to H2O2 stress management and parasite growth. Blocking both pathways resulted in ∼10-fold increase of susceptibility to H2O2 stress and cell death. Unexpectedly, the same pathway redundancy was observed in glucose-rich and glucose-depleted conditions, suggesting that gluconeogenesis can feed the PPP to provide NADPH. This was confirmed by (i) a lethal phenotype of RNAi-mediated depletion of glucose-6-phosphate isomerase (PGI) in the glucose-depleted Δmec/Δmec null background, (ii) an ∼10-fold increase of susceptibility to H2O2 stress observed for the Δmec/Δmec/(RNAi)PGI double mutant when compared with the single mutants, and (iii) the (13)C enrichment of glycolytic and PPP intermediates from cells incubated with [U-(13)C]proline, in the absence of glucose. Gluconeogenesis-supported NADPH supply may also be important for nucleotide and glycoconjugate syntheses in the insect host.

  1. The response of trypanosomes and other eukaryotes to ER stress and the spliced leader RNA silencing (SLS) pathway in Trypanosoma brucei.

    Science.gov (United States)

    Michaeli, Shulamit

    2015-01-01

    The unfolded protein response (UPR) is induced when the quality control machinery of the cell is overloaded with unfolded proteins or when one of the functions of the endoplasmic reticulum (ER) is perturbed. Here, I describe UPR in yeast and mammals, and compare it to what we know about pathogenic fungi and the parasitic protozoans from the order kinetoplastida, focusing on the novel pathway the spliced leader silencing (SLS) in Trypanosoma brucei. Trypanosomes lack conventional transcription regulation, and thus, lack most of the UPR machinery present in other eukaryotes. Trypanosome genes are transcribed in polycistronic units that are processed by trans-splicing and polyadenylation. In trans-splicing, which is essential for processing of each mRNA, an exon known as the spliced leader (SL) is added to all mRNAs from a small RNA, the SL RNA. Under severe ER stress, T. brucei elicits the SLS pathway. In SLS, the transcription of the SL RNA gene is extinguished, and the entire transcription complex dissociates from the SL RNA promoter. Induction of SLS is mediated by an ER-associated kinase (PK3) that migrates to the nucleus, where it phosphorylates the TATA-binding protein (TRF4), leading shut-off of SL RNA transcription. As a result, trans-splicing is inhibited and the parasites activate a programmed cell death (PCD) pathway. Despite the ability to sense the ER stress, the different eukaryotes, especially unicellular parasites and pathogenic fungi, developed a variety of unique and different ways to sense and adjust to this stress in a manner different from their host.

  2. Megazol and its bioisostere 4H-1,2,4-triazole: comparing the trypanocidal, cytotoxic and genotoxic activities and their in vitro and in silico interactions with the Trypanosoma brucei nitroreductase enzyme

    Directory of Open Access Journals (Sweden)

    Alcione Silva de Carvalho

    2014-06-01

    Full Text Available Megazol (7 is a 5-nitroimidazole that is highly active against Trypanosoma cruzi and Trypanosoma brucei, as well as drug-resistant forms of trypanosomiasis. Compound 7 is not used clinically due to its mutagenic and genotoxic properties, but has been largely used as a lead compound. Here, we compared the activity of 7 with its 4H-1,2,4-triazole bioisostere (8 in bloodstream forms of T. brucei and T. cruzi and evaluated their activation by T. brucei type I nitroreductase (TbNTR enzyme. We also analysed the cytotoxic and genotoxic effects of these compounds in whole human blood using Comet and fluorescein diacetate/ethidium bromide assays. Although the only difference between 7 and 8 is the substitution of sulphur (in the thiadiazole in 7 for nitrogen (in the triazole in 8, the results indicated that 8 had poorer antiparasitic activity than 7 and was not genotoxic, whereas 7 presented this effect. The determination of Vmax indicated that although 8 was metabolised more rapidly than 7, it bounds to the TbNTR with better affinity, resulting in equivalent kcat/KM values. Docking assays of 7 and 8 performed within the active site of a homology model of the TbNTR indicating that 8 had greater affinity than 7.

  3. The antiprotozoal activity of sixteen asteraceae species native to Sudan and bioactivity-guided isolation of xanthanolides from Xanthium brasilicum.

    Science.gov (United States)

    Nour, Amal M M; Khalid, Sami A; Kaiser, Marcel; Brun, Reto; Abdallah, Wai'l E; Schmidt, Thomas J

    2009-10-01

    In vitro screening of the dichloromethane extracts of 16 Asteraceae species native to Sudan for activity against major protozoan pathogens revealed that a Xanthium brasilicum Vell. [syn. X. strumarium var. brasilicum (Vell.) Baker in Mart.] extract was the most active against Trypanosoma brucei rhodesiense, the etiological agent of East African human trypanosomiasis (IC(50) = 0.1 microg/mL). This plant extract also exhibited noticeable activities against T. cruzi (Chagas disease), Leishmania donovani (Kala-Azar) as well as Plasmodium falciparum (Malaria tropica). Bioactivity-guided fractionation resulted in the isolation of four bioactive sesquiterpene lactones (STL) of the xanthanolide series (4,5-seco-guaianolide-type). They were identified by spectroscopic means as 8-epixanthatin (1), 8-epixanthatin 1beta,5beta-epoxide (2), and as the dimers pungiolide A (4) as well as pungiolide B (5). Two further modified xanthanolide sesquiterpene lactones, xanthipungolide (3) and 4,15-dinor-1,11(13)-xanthadiene-3,5beta:12,8beta-diolide (6) were isolated. While xanthipungolide turned out to be inactive against the tested parasites, the dinor-xanthanlide showed significant activity against T. brucei rhodesiense and L. donovani. All isolated compounds were previously known from other Xanthium species but this is the first report on their occurrence in X. brasilicum, and, most notably, on their antiprotozoal activity. As the most active single compound from this extract, 8-epixanthatin 1beta,5beta-epoxide showed IC(50) values of 0.09, 2.95, 0.16 and 1.71 microg/mL (0.33, 11.3, 0.6 and 6.5 microM) against T. brucei rhodesiense, T. cruzi, L. donovani and P. falciparum, respectively, while its cytotoxicity against rat myoblast cells used as control was determined at 5.8 microg/mL (22.1 microM). Besides assessment of their antiprotozoal activity, the structural assignments for the dimeric xanthanolides pungiolide A and B were reinvestigated and fully established. PMID:19431098

  4. Isolated dextrogastria

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Kyung Soo; Kim, Soo Ryun; Lee, Yong Chul; Park, Soo Soung [Chung Ang University College of Medicine, Seoul (Korea, Republic of); Sim, Young Soo [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1982-06-15

    Isolated situs inversus of the stomach with otherwise normal position of the thoracic and abdominal viscera is an extremely rare anomaly occurring in two district forms. Majority of cases are associated with eventration of the diphragm and are reported as being confused with spontaneous pneumothorax or pyopneumothorax at base of the right lung. The right sided stomach may produce interesting and confusing changes in liver scan. We have experienced 2 cases of the isolated dextrogastria.

  5. Isolated dextrogastria

    International Nuclear Information System (INIS)

    Isolated situs inversus of the stomach with otherwise normal position of the thoracic and abdominal viscera is an extremely rare anomaly occurring in two district forms. Majority of cases are associated with eventration of the diphragm and are reported as being confused with spontaneous pneumothorax or pyopneumothorax at base of the right lung. The right sided stomach may produce interesting and confusing changes in liver scan. We have experienced 2 cases of the isolated dextrogastria

  6. Biochemical analysis of PIFTC3, the Trypanosoma brucei orthologue of nematode DYF-13, reveals interactions with established and putative intraflagellar transport components.

    Science.gov (United States)

    Franklin, Joseph B; Ullu, Elisabetta

    2010-10-01

    DYF-13, originally identified in Caenorhabditis elegans within a collection of dye-filling chemosensory mutants, is one of several proteins that have been classified as putatively involved in intraflagellar transport (IFT), the bidirectional movement of protein complexes along cilia and flagella and specifically in anterograde IFT. Although genetic studies have highlighted a fundamental role of DYF-13 in nematode sensory cilium and trypanosome flagellum biogenesis, biochemical studies on DYF-13 have lagged behind. Here, we show that in Trypanosoma brucei the orthologue to DYF-13, PIFTC3, participates in a macromolecular complex of approximately 660 kDa. Mass spectroscopy of affinity-purified PIFTC3 revealed several components of IFT complex B as well as orthologues of putative IFT factors DYF-1, DYF-3, DYF-11/Elipsa and IFTA-2. DYF-11 was further analysed and shown to be concentrated near the basal bodies and in the flagellum, and to be required for flagellum elongation. In addition, by coimmunoprecipitation we detected an interaction between DYF-13 and IFT122, a component of IFT complex A, which is required for retrograde transport. Thus, our biochemical analysis supports the model, proposed by genetic analysis in C. elegans, that the trypanosome orthologue of DYF-13 plays a central role in the IFT mechanism. PMID:20923419

  7. Coenzyme Q10 prevented full blown splenomegaly and decreased melarsoprol-induced reactive encephalopathy in mice infected with Trypanosoma brucei rhodesiense

    Institute of Scientific and Technical Information of China (English)

    James Nyabuga Nyariki; John Kibuthu Thuita; Grace Kemunto Nyambati; Alfred Orina Isaac

    2014-01-01

    Objective: To establish the modulatory effects of coenzyme Q10 on experimental trypanosome infections in mice and evaluate the risk of occurrence and severity of melarsoprol-induced post treatment reactive encephalopathy (PTRE). Methods: Female Swiss white mice were orally administered with 200 mg/kg of coenzyme Q10 after which they were intraperitoneally inoculated with Trypanasoma brucei rhodesiense (T. b. rhodesiense). The resultant infection was allowed to develop and simulate all phases of human African trypanosomiasis and PTRE. Parasitaemia development, packed cell volume, haematological and pathological changes were determined. Results:A histological study in the brain tissue of T. b. rhodesiense infected mice demonstrated neuroinflammatory pathology which was highly amplified in the PTRE-induced groups. A prominent reduction in the severity of the neuroinflammatory response was detected when coenzyme-Q10 was administered. Furthermore, the mean tissue weight of spleen to body ratio in coenzyme Q10 supplemented group was significantly (P Conclusions: The capacity of coenzyme Q10 to alter the pathogenesis of T. b. rhodesiense infection in mice and following treatment with melarsoprol, may find application by rendering humans and animals less susceptible to deleterious effects of trypanosome infection such as splenomegaly and melarsoprol-induced PTRE and neurotoxicity.

  8. Exposure of Trypanosoma brucei to an N-acetylglucosamine-binding lectin induces VSG switching and glycosylation defects resulting in reduced infectivity.

    Directory of Open Access Journals (Sweden)

    Víctor M Castillo-Acosta

    2015-03-01

    Full Text Available Trypanosoma brucei variant surface glycoproteins (VSG are glycosylated by both paucimannose and oligomannose structures which are involved in the formation of a protective barrier against the immune system. Here, we report that the stinging nettle lectin (UDA, with predominant N-acetylglucosamine-binding specificity, interacts with glycosylated VSGs and kills parasites by provoking defects in endocytosis together with impaired cytokinesis. Prolonged exposure to UDA induced parasite resistance based on a diminished capacity to bind the lectin due to an enrichment of biantennary paucimannose and a reduction of triantennary oligomannose structures. Two molecular mechanisms involved in resistance were identified: VSG switching and modifications in N-glycan composition. Glycosylation defects were correlated with the down-regulation of the TbSTT3A and/or TbSTT3B genes (coding for oligosaccharyltransferases A and B, respectively responsible for glycan specificity. Furthermore, UDA-resistant trypanosomes exhibited severely impaired infectivity indicating that the resistant phenotype entails a substantial fitness cost. The results obtained further support the modification of surface glycan composition resulting from down-regulation of the genes coding for oligosaccharyltransferases as a general resistance mechanism in response to prolonged exposure to carbohydrate-binding agents.

  9. The glycosylphosphatidylinositol-PLC in Trypanosoma brucei forms a linear array on the exterior of the flagellar membrane before and after activation.

    Science.gov (United States)

    Hanrahan, Orla; Webb, Helena; O'Byrne, Robert; Brabazon, Elaine; Treumann, Achim; Sunter, Jack D; Carrington, Mark; Voorheis, H Paul

    2009-06-01

    Bloodstream forms of Trypanosoma brucei contain a glycosylphosphatidylinositol-specific phospholipase C (GPI-PLC) that cleaves the GPI-anchor of the variable surface glycoprotein (VSG). Its location in trypanosomes has been controversial. Here, using confocal microscopy and surface labelling techniques, we show that the GPI-PLC is located exclusively in a linear array on the outside of the flagellar membrane, close to the flagellar attachment zone, but does not co-localize with the flagellar attachment zone protein, FAZ1. Consequently, the GPI-PLC and the VSG occupy the same plasma membrane leaflet, which resolves the topological problem associated with the cleavage reaction if the VSG and the GPI-PLC were on opposite sides of the membrane. The exterior location requires the enzyme to be tightly regulated to prevent VSG release under basal conditions. During stimulated VSG release in intact cells, the GPI-PLC did not change location, suggesting that the release mechanism involves lateral diffusion of the VSG in the plane of the membrane to the fixed position of the GPI-PLC.

  10. Depletion of the SR-Related Protein TbRRM1 Leads to Cell Cycle Arrest and Apoptosis-Like Death in Trypanosoma brucei

    Science.gov (United States)

    Levy, Gabriela V.; Moretti, Georgina; Tekiel, Valeria S.; Sánchez, Daniel O.

    2015-01-01

    Arginine-Serine (RS) domain-containing proteins are RNA binding proteins with multiple functions in RNA metabolism. In mammalian cells this group of proteins is also implicated in regulation and coordination of cell cycle and apoptosis. In trypanosomes, an early branching group within the eukaryotic lineage, this group of proteins is represented by 3 members, two of them are SR proteins and have been recently shown to be involved in rRNA processing as well as in pre-mRNA splicing and stability. Here we report our findings on the 3rd member, the SR-related protein TbRRM1. In the present study, we showed that TbRRM1 ablation by RNA-interference in T. brucei procyclic cells leads to cell-cycle block, abnormal cell elongation compatible with the nozzle phenotype and cell death by an apoptosis-like mechanism. Our results expand the role of the trypanosomal RS-domain containing proteins in key cellular processes such as cell cycle and apoptosis-like death, roles also carried out by the mammalian SR proteins, and thus suggesting a conserved function in this phylogenetically conserved protein family. PMID:26284933

  11. Identification of a bacterial-like HslVU protease in the mitochondria of Trypanosoma brucei and its role in mitochondrial DNA replication.

    Directory of Open Access Journals (Sweden)

    Ziyin Li

    2008-04-01

    Full Text Available ATP-dependent protease complexes are present in all living organisms, including the 26S proteasome in eukaryotes, Archaea, and Actinomycetales, and the HslVU protease in eubacteria. The structure of HslVU protease resembles that of the 26S proteasome, and the simultaneous presence of both proteases in one organism was deemed unlikely. However, HslVU homologs have been identified recently in some primordial eukaryotes, though their potential function remains elusive. We characterized the HslVU homolog from Trypanosoma brucei, a eukaryotic protozoan parasite and the causative agent of human sleeping sickness. TbHslVU has ATP-dependent peptidase activity and, like its bacterial counterpart, has essential lysine and N-terminal threonines in the catalytic subunit. By epitope tagging, TbHslVU localizes to mitochondria and is associated with the mitochondrial genome, kinetoplast DNA (kDNA. RNAi of TbHslVU dramatically affects the kDNA by causing over-replication of the minicircle DNA. This leads to defects in kDNA segregation and, subsequently, to continuous network growth to an enormous size. Multiple discrete foci of nicked/gapped minicircles are formed on the periphery of kDNA disc, suggesting a failure in repairing the gaps in the minicircles for kDNA segregation. TbHslVU is a eubacterial protease identified in the mitochondria of a eukaryote. It has a novel function in regulating mitochondrial DNA replication that has never been observed in other organisms.

  12. The serum of rabbitfish (Siganus oramin) has antimicrobial activity to some pathogenic organisms and a novel serum L-amino acid oxidase is isolated.

    Science.gov (United States)

    Wang, Fanghua; Li, Ruijun; Xie, Mingquan; Li, Anxing

    2011-01-01

    The serum of rabbitfish (Siganus oramin) has been confirmed previously to have killing effect to Cryptocaryon irritans, an important marine ciliate protozoan that causes a disease referred to as "marine white spot disease". Herein, we find the serum of the rabbitfish also shows antibacterial activity against both gram-positive and gram-negative bacteria and has killing effect on two other parasites: Trypanosoma brucei brucei, Ichthyophthirius multifiliis. Results of scanning electron microscopy indicated that after treating with rabbitfish serum, the surface of the Staphylococcus aureus was wrinkled and pores were formed on the surface of Escherichia coli. Serum of the rabbitfish possesses a strong killing effect to Ichthyophthirius multifiliis in vitro, causing a similar effect as to C. irritans. The serum of rabbitfish also showed strong killing effect to T. b. brucei in vitro, with the minimus trypanocidal titre (MTT) only to be 1.5% in 1 h. Results of laser confocal fluorescence microscopy indicated that rabbitfish serum could also induce cell rupture of T. b. brucei. A novel antimicrobial protein (SR-LAAO) was isolated from the serum of rabbitfish by using ultrafiltration, reversed phase high performance liquid chromatography (RP-HPLC) and Native polyacrylamide gel electrophoresis (Native-PAGE). Results of gel overlay assay showed that the protein could act alone to inhibit the growth of S. aureus and E. coli. Results of western blot and automated Edman degradation showed that it was the same as the antiparasitic protein (APP) reported before to have killing effect on C. irritans. Full length cDNA sequence of the SR-LAAO was cloned. BLAST research suggested that the cDNA of SR-LAAO has a close similarity with a number of L-amino acid oxidases (LAAOs) and possesses two conserved motifs that exist in LAAOs. Combined, these results demonstrate that this protein which has antimicrobial activity to some pathogenic organisms was a novel LAAO found in the serum of

  13. Isoler nu

    DEFF Research Database (Denmark)

    Andersen, N.E.; Ankerstjerne, P.; Jørgensen, B.;

    Omfattende vejledning, der angiver, hvordan energiforbruget i eksisterende huse kan nedbringes ved isolering, tætning og forbedring af varmeanlægget, og hvor meget det koster. Anvisningen indeholder detaljerede eksempler på efterisolering af ydervægge, tage, gulve og vinduer. Henvender sig til ej...

  14. Genome-wide expression profiling of in vivo-derived bloodstream parasite stages and dynamic analysis of mRNA alterations during synchronous differentiation in Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Ghazal Peter

    2009-09-01

    Full Text Available Abstract Background Trypanosomes undergo extensive developmental changes during their complex life cycle. Crucial among these is the transition between slender and stumpy bloodstream forms and, thereafter, the differentiation from stumpy to tsetse-midgut procyclic forms. These developmental events are highly regulated, temporally reproducible and accompanied by expression changes mediated almost exclusively at the post-transcriptional level. Results In this study we have examined, by whole-genome microarray analysis, the mRNA abundance of genes in slender and stumpy forms of T.brucei AnTat1.1 cells, and also during their synchronous differentiation to procyclic forms. In total, five biological replicates representing the differentiation of matched parasite populations derived from five individual mouse infections were assayed, with RNAs being derived at key biological time points during the time course of their synchronous differentiation to procyclic forms. Importantly, the biological context of these mRNA profiles was established by assaying the coincident cellular events in each population (surface antigen exchange, morphological restructuring, cell cycle re-entry, thereby linking the observed gene expression changes to the well-established framework of trypanosome differentiation. Conclusion Using stringent statistical analysis and validation of the derived profiles against experimentally-predicted gene expression and phenotypic changes, we have established the profile of regulated gene expression during these important life-cycle transitions. The highly synchronous nature of differentiation between stumpy and procyclic forms also means that these studies of mRNA profiles are directly relevant to the changes in mRNA abundance within individual cells during this well-characterised developmental transition.

  15. Micro RNA expression profiles in peripheral blood cells of rats that were experimentally infected with Trypanosoma congolense and different Trypanosoma brucei subspecies.

    Science.gov (United States)

    Simo, Gustave; Lueong, Smiths; Grebaut, Pascal; Guny, Gerard; Hoheisel, Jörg D

    2015-08-01

    To identify miRNAs whose expression are differentially regulated during trypanosome infections a microarray targeting more than 600 rat miRNA was used to analyze the miRNA expression profiles between uninfected rats and animals infected by Trypanosoma congolense and Trypanosoma brucei s.l. The potential targets of dysregulated miRNAs as well as their biological pathways and functions were predicted using several bioinformatics software tools. Irrespective of the infecting trypanosome species, eight miRNAs (seven up- and one down-regulated) were dysregulated during infections. Moreover, other miRNAs were differentially regulated in rats infected by specific trypanosome species. Functional analyses of differentially regulated miRNAs indicated their involvement in diverse biological processes. Among these, transcription repressor activity, gene expression control as well as protein transporter activity were predominant. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of dysregulated miRNAs revealed their involvement in several biological pathways and disease conditions. This suggests possible modulation of such pathways following trypanosome infection; for example, the MAPK signaling pathway which is known to play vital roles in apoptosis, innate immune response and response to viral infections was highly affected. Axon guidance was equally highly impacted and may indicate a cross reactivity between pathogen proteins and guidance molecules representing one pathological mechanism as it has been observed with influenza HA. Furthermore, Ingenuity pathway analyses of dysregulated miRNAs and potential targets indicated strong association with inflammatory responses, cell death and survival as well as infectious diseases. The data generated here provide valuable information to understand the regulatory function of miRNAs during trypanosome infections. They improved our knowledge on host-parasite cross-talks and provide a framework for investigations to

  16. Structure determination of glycogen synthase kinase-3 from Leishmania major and comparative inhibitor structure-activity relationships with Trypanosoma brucei GSK-3

    Energy Technology Data Exchange (ETDEWEB)

    Ojo, Kayode K; Arakaki, Tracy L; Napuli, Alberto J; Inampudi, Krishna K; Keyloun, Katelyn R; Zhang, Li; Hol, Wim G.J.; Verlind, Christophe L.M.J.; Merritt, Ethan A; Van Voorhis, Wesley C [UWASH

    2012-04-24

    Glycogen synthase kinase-3 (GSK-3) is a drug target under intense investigation in pharmaceutical companies and constitutes an attractive piggyback target for eukaryotic pathogens. Two different GSKs are found in trypanosomatids, one about 150 residues shorter than the other. GSK-3 short (GeneDB: Tb927.10.13780) has previously been validated genetically as a drug target in Trypanosoma brucei by RNAi induced growth retardation; and chemically by correlation between enzyme and in vitro growth inhibition. Here, we report investigation of the equivalent GSK-3 short enzymes of L. major (LmjF18.0270) and L. infantum (LinJ18_V3.0270, identical in amino acid sequences to LdonGSK-3 short) and a crystal structure of LmajGSK-3 short at 2 Å resolution. The inhibitor structure-activity relationships (SARs) of L. major and L. infantum are virtually identical, suggesting that inhibitors could be useful for both cutaneous and visceral leishmaniasis. Leishmania spp. GSK-3 short has different inhibitor SARs than TbruGSK-3 short, which can be explained mostly by two variant residues in the ATP-binding pocket. Indeed, mutating these residues in the ATP-binding site of LmajGSK-3 short to the TbruGSK-3 short equivalents results in a mutant LmajGSK-3 short enzyme with SAR more similar to that of TbruGSK-3 short. The differences between human GSK-3β (HsGSK-3β) and LmajGSK-3 short SAR suggest that compounds which selectively inhibit LmajGSK-3 short may be found.

  17. Eksistentiel Isolation

    OpenAIRE

    Matikainen, Oliver Albert; Andersen, Kian Alexander; Thorup, Johannes Hoff; Slotsager, Christian Knud; Jensen, Mette Ingersholm; Bachmann, Zenia Gruhl; Razga, Pauline Marie

    2015-01-01

    This study examines whether or not isolation can lead to personal growth. In order to answer this question we distinguish between loneliness and aloneness. We explain the theory of existential psychotherapist Irvin D. Yalom and on the basis of this examination, we analyze a conducted interview through the theory. Based on the theory, interview and analysis, we discuss the validity of Yalom’s theory. Considering the examination, the analysis and the distinction between the two types of isolati...

  18. Challenges in Diagnosing Human African Trypanosomiasis: Evaluation of the MSF OCG project in Dingila, DRC

    OpenAIRE

    Van Nieuwenhove, Simon

    2015-01-01

    Between late 2010 and the end of 2014 and under extremely difficult conditions, Médecins sans Frontières (MSF) carried out a project to combat Human African Trypanosomiasis (HAT), also known as sleeping sickness, in the Dingila, Ango and Zobia regions of Orientale Province in the Democratic Republic of Congo (DRC). HAT in DRC is caused by Trypanosoma brucei gambiense and is transmitted by the tsetse fly (Glossina genus) of the Palpalis group. Without effective treatment, virtually all f...

  19. Population Vulnerability and Disability in Kenya's Tsetse Fly Habitats

    OpenAIRE

    Grady, Sue C.; Messina, Joseph P.; McCord, Paul F.

    2011-01-01

    BACKGROUND: Human African Trypanosomiasis (HAT), also referred to as sleeping sickness, and African Animal Trypanosomaisis (AAT), known as nagana, are highly prevalent parasitic vector-borne diseases in sub-Saharan Africa. Humans acquire trypanosomiasis following the bite of a tsetse fly infected with the protozoa Trypanosoma brucei (T.b.) spp. -i.e., T.b. gambiense in West and Central Africa and T.b. rhodesiense in East and Southern Africa. Over the last decade HAT diagnostic capacity to est...

  20. Sulfated phenolic compounds from Limonium caspium: Isolation, structural elucidation, and biological evaluation

    Science.gov (United States)

    Gadetskaya, Anastassiya V.; Tarawneh, Amer H.; Zhusupova, Galiya E.; Gemejiyeva, Nadezhda G.; Cantrell, Charles L.; Cutler, Stephen J.; Ross, Samir A.

    2016-01-01

    Three new compounds, (2S,3S)-5-methyldihydromyricetin (1), (2S,3S)-5-methyldihydromyricetin-3′-O-sulfate (2) and β-D-glucopyranoside, 3-methyl, but-3-en-1-yl 4-O-α-L-rhamnopyranosyl (3) have been isolated from the Limonium caspium, together with dihydromyricetin (4), dihydromyricetin-3′-O-sulfate (5), myricetin-3′-O-sulfate (6), 5-methylmyricetin (7), myricetin (8), myricetin-3-O-β-glucoside (9), as well as phloridzin (10), and tyramine (11). Compounds 5 and 6 were isolated for the first time as acids. This is the first report of all these compounds from this plant. Their structures were established by extensive NMR studies (1H NMR, 13C NMR, DEPT, 1H–1H COSY, HSQC, HMBC) as well as HRESIMS. All isolated compounds were evaluated for their antibacterial, antifungal, antimalarial and antileishmanial activities. Compounds 7, 8 and 9 exhibited good antifungal activity against Candida glabrata with IC50 values of 6.79, 15.37 and 8.53 μg/mL, respectively. Compound 8 displayed significant antimalarial activity against resistant and sensitive strains of Plasmodium falciparum with IC50 values of 1.82 and 1.51 μg/mL, respectively. Compounds 1, 4, 6, 8 and 9 showed excellent activity against Trypanosoma brucei with IC50 values of 6.93, 9.65, 8.52, 7.67 and 6.31 μg/mL, respectively. To date, this is the first report on the phytochemical and biological activity of secondary metabolites from L. caspium. PMID:26025854

  1. Molecular markers for the different (sub)-species of the Trypanozoon subgenus

    International Nuclear Information System (INIS)

    During the past years, species specific PCRs for identifying the different taxa within the Trypanozoon subgenus have been developed by our laboratory. For the detection of the two human pathogenic Trypanosomes, PCR-SRA for T.b.rhodesiense and PCR-TgsGP gene for T.b. gambiense exist now. For animal Trypanosomiasis, a T.evansi specific PCR based on the RoTat 1.2 VSG was developed. Only for T.b.brucei and T.equiperdum, no specific markers could be identified. However, results examine here indicate that T.equiperdum is more closely related to T.b.brucei than to T.evansi and even might be a particular strain of T b.brucei. (author)

  2. Understand Quarantine and Isolation

    Science.gov (United States)

    ... Social Media What CDC is Doing Blog: Public Health Matters What's New Preparation & Planning Emergency Preparedness and Response Understand Quarantine and Isolation Recommend on Facebook Tweet Share Compartir Isolation and quarantine help protect the public by ...

  3. Mutation and premating isolation.

    Science.gov (United States)

    Woodruff, R C; Thompson, J N

    2002-11-01

    While premating isolation might be traceable to different genetic mechanisms in different species, evidence supports the idea that as few as one or two genes may often be sufficient to initiate isolation. Thus, new mutation can theoretically play a key role in the process. But it has long been thought that a new isolation mutation would fail, because there would be no other individuals for the isolation-mutation-carrier to mate with. We now realize that premeiotic mutations are very common and will yield a cluster of progeny carrying the same new mutant allele. In this paper, we discuss the evidence for genetically simple premating isolation barriers and the role that clusters of an isolation mutation may play in initiating allopatric, and even sympatric, species divisions.

  4. Genetics Home Reference: isolated growth hormone deficiency

    Science.gov (United States)

    ... deficiency dwarfism, pituitary growth hormone deficiency dwarfism isolated GH deficiency isolated HGH deficiency isolated human growth hormone deficiency isolated somatotropin deficiency isolated somatotropin deficiency disorder ...

  5. Population genomics reveals the origin and asexual evolution of human infective trypanosomes.

    Science.gov (United States)

    Weir, William; Capewell, Paul; Foth, Bernardo; Clucas, Caroline; Pountain, Andrew; Steketee, Pieter; Veitch, Nicola; Koffi, Mathurin; De Meeûs, Thierry; Kaboré, Jacques; Camara, Mamadou; Cooper, Anneli; Tait, Andy; Jamonneau, Vincent; Bucheton, Bruno; Berriman, Matt; MacLeod, Annette

    2016-01-01

    Evolutionary theory predicts that the lack of recombination and chromosomal re-assortment in strictly asexual organisms results in homologous chromosomes irreversibly accumulating mutations and thus evolving independently of each other, a phenomenon termed the Meselson effect. We apply a population genomics approach to examine this effect in an important human pathogen, Trypanosoma brucei gambiense. We determine that T.b. gambiense is evolving strictly asexually and is derived from a single progenitor, which emerged within the last 10,000 years. We demonstrate the Meselson effect for the first time at the genome-wide level in any organism and show large regions of loss of heterozygosity, which we hypothesise to be a short-term compensatory mechanism for counteracting deleterious mutations. Our study sheds new light on the genomic and evolutionary consequences of strict asexuality, which this pathogen uses as it exploits a new biological niche, the human population. PMID:26809473

  6. Alternativ isolering i bygninger

    DEFF Research Database (Denmark)

    Andersen, T.; Skibstrup Eriksen, S.

    Denne SBI-meddelelse beskriver resultaterne af en undersøgelse af bygninger, hvor der er anvendt alternativ isolering. Undersøgelsen omfatter termografering og fugtmåling af udvendige bygningsdele isoleret med alternativ isolering. Endvidere rapporteres resultaterne af målinger af indholdet af tu...

  7. Extremely Isolated Elliptical Galaxies

    Science.gov (United States)

    Fuse, Christopher R.; Marcum, P.; Fanelli, M.; Aars, C.

    2006-06-01

    Isolated galaxies provide a means of assessing the evolution of galactic systems. Extremely isolated galaxies define a zero-interaction baseline for comparative studies of galaxy evolution. We present results of a search for isolated elliptical galaxies (IEGs). We utilize the optical imaging data produced by the Sloan Digital Sky Survey (SDSS) to identify candidate galaxies from Release 1-4 of the SDSS. Candidate IEGs meet strict isolation criteria: Any IEG must be separated by at least 2.5 Mpc from any neighboring non-dwarf galaxy having a MV fainter than -16.5 mag. The candidate isolated systems have no non-dwarf neighbors within a distance such that we can insure that the IEGs have never interacted with another existing galaxy since formation.In order to increase the signal-to-noise ratio, we have used the SDSS images in the u,g,r filters to create combined sets of images for each IEG. The stacked images permit a more robust determination of the morphology of the candidate galaxies. Verification that these are spheroidal systems is achieved through a bulge/disk decomposition technique using standard surface photometry. Our preliminary sample of 51 isolated systems defines a complete volume-limited population of extremely isolated early-type galaxies within a distance of 72Mpc

  8. Haptoglobin-hemoglobin receptor independent killing of African trypanosomes by human serum and trypanosome lytic factors.

    Science.gov (United States)

    Bullard, Whitney; Kieft, Rudo; Capewell, Paul; Veitch, Nicola J; Macleod, Annette; Hajduk, Stephen L

    2012-01-01

    The haptoglobin-hemoglobin receptor (HpHbR) of African trypanosomes plays a critical role in human innate immunity against these parasites. Localized to the flagellar pocket of the veterinary pathogen Trypanosoma brucei brucei this receptor binds Trypanosome Lytic Factor-1 (TLF-1), a subclass of human high-density lipoprotein (HDL) facilitating endocytosis, lysosomal trafficking and subsequent killing. Recently, we found that group 1 Trypanosoma brucei gambiense does not express a functional HpHbR. We now show that loss of the TbbHpHbR reduces the susceptibility of T. b. brucei to human serum and TLF-1 by 100- and 10,000-fold, respectively. The relatively high concentrations of human serum and TLF-1 needed to kill trypanosomes lacking the HpHbR indicates that high affinity TbbHpHbR binding enhances the cytotoxicity; however, in the absence of TbbHpHbR, other receptors or fluid phase endocytosis are sufficient to provide some level of susceptibility. Human serum contains a second innate immune factor, TLF-2, that has been suggested to kill trypanosomes independently of the TbbHpHbR. We found that T. b. brucei killing by TLF-2 was reduced in TbbHpHbR-deficient cells but to a lesser extent than TLF-1. This suggests that both TLF-1 and TLF-2 can be taken up via the TbbHpHbR but that alternative pathways exist for the uptake of these toxins. Together the findings reported here extend our previously published studies and suggest that group 1 T. b. gambiense has evolved multiple mechanisms to avoid killing by trypanolytic human serum factors. PMID:22286709

  9. Alternativ isolering i bygninger

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place

    2001-01-01

    Resume af rapport om målinger på alternative isoleringsmaterialer i bygninger, udgivet af Statens Byggeforskningsinstitut (SBI meddelelse 128) under Energistyrelsens udviklingsprogram "Miljø- og arbejdsmiljøvenlig isolering"...

  10. Base isolation: Fresh insight

    Energy Technology Data Exchange (ETDEWEB)

    Shustov, V.

    1993-07-15

    The objective of the research is a further development of the engineering concept of seismic isolation. Neglecting the transient stage of seismic loading results in a widespread misjudgement: The force of resistance associated with velocity is mostly conceived as a source of damping vibrations, though it is an active force at the same time, during an earthquake type excitation. For very pliant systems such as base isolated structures with relatively low bearing stiffness and with artificially added heavy damping mechanism, the so called `damping`` force may occur even the main pushing force at an earthquake. Thus, one of the two basic pillars of the common seismic isolation philosophy, namely, the doctrine of usefulness and necessity of a strong damping mechanism, is turning out to be a self-deception, sometimes even jeopardizing the safety of structures and discrediting the very idea of seismic isolation. There is a way out: breaking with damping dependancy.

  11. Isolation of Human Eosinophils

    OpenAIRE

    Akuthota, Praveen; Shamri, Revital; Weller, Peter F.

    2012-01-01

    Highly purified eosinophils can be isolated from peripheral blood by negative selection using an antibody-based magnetic negative selection protocol. The basic protocol describes a sequential fractionation of peripheral blood in which CD16+ granulocytes are enriched first from whole blood, followed by isolation of eosinophils. This technique is easy to use, fast, and highly reproducible. Support protocols describe a staining methods that can be used to evaluate the purity of eosinophils and d...

  12. Isolated sleep paralysis

    OpenAIRE

    Sawant, Neena S.; Shubhangi R Parkar; Tambe, Ravindra

    2005-01-01

    Sleep paralysis (SP) is a cardinal symptom of narcolepsy. However, little is available in the literature about isolated sleep paralysis. This report discusses the case of a patient with isolated sleep paralysis who progressed from mild to severe SP over 8 years. He also restarted drinking alcohol to be able to fall asleep and allay his anxiety symptoms. The patient was taught relaxation techniques and he showed complete remission of the symptoms of SP on follow up after 8 months.

  13. Défis en matière de diagnostic de la Trypanosomiase Humaine Africaine: Evaluation du projet de MSF OCG à Dingila, RDC

    OpenAIRE

    Van Nieuwenhove, Simon

    2015-01-01

    Entre fin 2010 et fin 2014, Médecins sans Frontières (MSF) a, dans des conditions extrêmement difficiles, mené un projet de lutte contre la trypanosomiase humaine africaine (THA) ou maladie du sommeil dans la région de Dingila, Ango et Zobia, dans la Province Orientale de la République Démocratique du Congo (RDC). La THA en RDC est causée par Trypanosoma brucei gambiense et y est transmise par des glossines (mouches tsé-tsé) du groupe palpalis. Sans traitement efficace, quasi tous les malades...

  14. Isolated Fallopian Tube Torsion

    Directory of Open Access Journals (Sweden)

    S. Kardakis

    2013-01-01

    Full Text Available Isolated torsion of the Fallopian tube is a rare gynecological cause of acute lower abdominal pain, and diagnosis is difficult. There are no pathognomonic symptoms; clinical, imaging, or laboratory findings. A preoperative ultrasound showing tubular adnexal masses of heterogeneous echogenicity with cystic component is often present. Diagnosis can rarely be made before operation, and laparoscopy is necessary to establish the diagnosis. Unfortunately, surgery often is performed too late for tube conservation. Isolated Fallopian tube torsion should be suspected in case of acute pelvic pain, and prompt intervention is necessary.

  15. Motion of isolated bodies

    Energy Technology Data Exchange (ETDEWEB)

    Choquet-Bruhat, Yvonne [Academie des Sciences, 23 Quai de Conti, 75270 Paris Cedex 06 (France); Friedrich, Helmut [Max-Planck-Institut fuer Gravitationsphysik, Am Muehlenberg 1, 14476 Golm (Germany)

    2006-10-21

    It is shown that sufficiently smooth initial data for the Einstein-dust or the Einstein-Maxwell-dust equations with non-negative density of compact support develop into solutions representing isolated bodies in the sense that the matter field has spatially compact support and is embedded in an exterior vacuum solution.

  16. Motion of Isolated bodies

    CERN Document Server

    Choquet-Bruhat, Y; Choquet-Bruhat, Yvonne; Friedrich, Helmut

    2006-01-01

    It is shown that sufficiently smooth initial data for the Einstein-dust or the Einstein-Maxwell-dust equations with non-negative density of compact support develop into solutions representing isolated bodies in the sense that the matter field has spatially compact support and is embedded in an exterior vacuum solution.

  17. Chiral fiber optical isolator

    Science.gov (United States)

    Kopp, Victor I.; Zhang, Guoyin; Zhang, Sheng; Genack, Azriel Z.; Neugroschl, Dan

    2009-02-01

    We propose an in-fiber chiral optical isolator based on chiral fiber polarizer technology and calculate its performance by incorporating the magnetic field into the scattering matrix. The design will be implemented in a special preform, which is passed through a miniature heat zone as it is drawn and twisted. The birefringence of the fiber is controlled by adjusted the diameter of a dual-core optical fiber. By adjusting the twist, the fiber can convert linear to circular polarization and reject one component of circular polarization. In the novel central portion of the isolator, the fiber diameter is large. The effective birefringence of the circular central core with high Verdet constant embedded in an outer core of slightly smaller index of refraction is small. The central potion is a non-reciprocal polarization converter which passes forward traveling left circularly polarized (LCP) light as LCP, while converting backward propagating LCP to right circularly polarized (RCP) light. Both polarizations of light traveling backwards are scattered out of the isolator. Since it is an all-glass structure, we anticipate that the isolator will be able to handle several watts of power and will be environmentally robust.

  18. Isolated fructose malabsorption.

    OpenAIRE

    Wales, J. K.; Primhak, R A; Rattenbury, J; Taylor, C J

    1990-01-01

    A patient with isolated fructose malabsorption presented with diarrhoea and colic during the first year of life and subsequently responded to a fructose free diet. Fructose malabsorption has been implicated in some cases of irritable bowel syndrome in adults and may also be an infrequently recognised cause of gastrointestinal symptoms in children.

  19. Isolated jejunal varices.

    Directory of Open Access Journals (Sweden)

    Bhagwat S

    1995-04-01

    Full Text Available Isolated jejunal varices are an uncommon manifestation of portal hypertension. A one and a half year old boy presented with recurrent, massive gastrointestinal bleeding from jejunal varices. The bleeding site was identified at exploratory laparotomy. Jejunal resection and anastomosis resulted in complete resolution of the bleeding and there has been no recurrent bleeding over an eight month follow-up period.

  20. Proteoglycan isolation and analysis

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    2001-01-01

    Proteoglycans can be difficult molecules to isolate and analyze due to large mass, charge, and tendency to aggregate or form macromolecular complexes. This unit describes detailed methods for purification of matrix, cell surface, and cytoskeleton-linked proteoglycans. Methods for analysis...

  1. Method for isolating nucleic acids

    Science.gov (United States)

    Hurt, Jr., Richard Ashley; Elias, Dwayne A.

    2015-09-29

    The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

  2. Trypanosome resistance to human innate immunity: targeting Achilles' heel.

    Science.gov (United States)

    Stephens, Natalie A; Kieft, Rudo; Macleod, Annette; Hajduk, Stephen L

    2012-12-01

    Trypanosome lytic factors (TLFs) are powerful, naturally occurring toxins in humans that provide sterile protection against infection by several African trypanosomes. These trypanocidal complexes predominantly enter the parasite by binding to the trypanosome haptoglobin/hemoglobin receptor (HpHbR), trafficking to the lysosome, causing membrane damage and, ultimately, cell lysis. Despite TLF-mediated immunity, the parasites that cause human African Trypanosomiasis (HAT), Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense, have developed independent mechanisms of resistance to TLF killing. In this review we describe the parasite defenses that allow trypanosome infections of humans and discuss how targeting these apparent strengths of the parasite may reveal their Achilles' heel, leading to new approaches in the treatment of HAT. PMID:23059119

  3. Trypanosome resistance to human innate immunity: targeting Achilles’ heel

    Science.gov (United States)

    Stephens, Natalie A.; Kieft, Rudo; MacLeod, Annette; Hajduk, Stephen L.

    2015-01-01

    Trypanosome lytic factors (TLFs) are powerful, naturally-occurring toxins in humans that provide sterile protection against infection by several African trypanosomes. These trypanocidal complexes predominantly enter the parasite by binding to the trypanosome haptoglobin/hemoglobin receptor (HpHbR), trafficking to the lysosome, causing membrane damage and ultimately, cell lysis. Despite TLF-mediated immunity, the parasites that cause human African Trypanosomiasis (HAT), Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense, have developed independent mechanisms of resistance to TLF killing. Here we describe the parasite defenses that allow trypanosome infections of humans and discuss how targeting these apparent strengths of the parasite may reveal their Achilles’ heel, leading to new approaches in the treatment of HAT. PMID:23059119

  4. Facteurs socioculturels et contrôle de la Trypanosomiase Humaine Africaine en République Démocratique du Congo / Sociocultural factors and control of human African trypanosomiasis in the Democratic Republic of Congo

    OpenAIRE

    Mpanya Kabeya, Alain

    2015-01-01

    RESUMELa Trypanosomiase Humaine Africaine (THA) appelée également « maladie du sommeil» est une maladie parasitaire provoquée par un protozoaire du genre Trypanosoma dont deux sous-espèces (T. brucei gambiense et T. brucei rhodesiense) sont pathogènes à l’homme. La stratégie de lutte contre cette maladie est essentiellement basée sur le dépistage précoce et le traitement des malades, complété avec le contrôle du vecteur. Cependant, l’utilisation du service de dépistage de la THA par les commu...

  5. Isolated lung perfusion.

    Science.gov (United States)

    Cypel, Marcelo; Keshavjee, Shaf

    2012-01-01

    Isolated lung perfusion (ILP) has been historically used as a method to study basic lung physiologic concepts using animal models. More recently, ILP has been applied in lung transplantation and thoracic oncology. In lung transplantation, ILP has been used to assess physiological integrity of donor lungs after the organ is removed from the donor. This procedure is called Ex vivo Lung Perfusion (EVLP), and it has also been proposed as a method for active treatment and repair of injured unsuitable donor organs ex vivo. In oncology, ILP is an attractive method to deliver high dose chemotherapy to treat pulmonary metastatic disease. Since the lung vasculature is isolated in vivo, this technique is called in vivo lung perfusion (IVLP). This review will focus on the rationale, technical aspects, experimental and clinical experience of EVLP and IVLP. A perspective on the future use of these techniques is described. PMID:22202033

  6. Ultrasonic thermometer isolation standoffs

    International Nuclear Information System (INIS)

    A method is provided for minimizing sticking of the transmission line to the protective sheath and preventing noise echoes from interfering with signal echoes in an improved high temperature ultrasonic thermometer which includes an ultrasonic transmission line surrounded by a protective sheath. Small isolation standoffs are mounted on the transmission line to minimize points of contact between the transmission line and the protective sheath, the isolation standoffs serving as discontinuities mounted on the transmission line at locations where a signal echo is desired or where an echo can be tolerated. Consequently any noise echo generated by the sticking of the standoff to the protective sheath only adds to the amplitude of the echo generated at the standoff and does not interfere with the other signal echoes. 6 claims, 3 figures

  7. High voltage isolation transformer

    Science.gov (United States)

    Clatterbuck, C. H.; Ruitberg, A. P. (Inventor)

    1985-01-01

    A high voltage isolation transformer is provided with primary and secondary coils separated by discrete electrostatic shields from the surfaces of insulating spools on which the coils are wound. The electrostatic shields are formed by coatings of a compound with a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools adjacent to the coils. Coatings of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs of a ferromagnetic core extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings, lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.

  8. Electron isolation at ATLAS

    International Nuclear Information System (INIS)

    The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of efficiently selecting interesting candidate events in pp collisions at 14 TeV centre-of-mass energy, whilst rejecting the enormous number of background events. Many of these interesting candidate events have isolated leptons in the final state, like for example events with a gauge boson or SUSY. On top of the standard ATLAS electron identification an isolation criterion has been developed using a likelihood as multivariate approach with several discriminating variables. The likelihood is constructed by selecting electrons from Z decays for the signal and for the background electrons from b quark jets. Results for the example of the associated Higgs boson production with top quarks and subsequent decay into a pair of W bosons are presented. In addition first results of a likelihood to discriminate against jets are given and a possible extension for muons is discussed

  9. Brown Fat Cell Isolation

    OpenAIRE

    sprotocols

    2014-01-01

    Author: C.R. Kahn ### 1.) ISOLATION AND PRIMARY CULTURE OF BROWN FAT PREADIPOCYTES ### Rationale: To prepare primary brown preadipocytes for immortalization: useful for metabolic studies from knockout mice. This consists of the following five protocols. References: Fasshauer, M., J. Klein, K M. Kriauciunas, K. Ueki, M.Benito, and C.R. Kahn. 2001. Essential role of insulin substrate 1 in differentiation of brown adipocytes. *Mol Cell Biol* 21: 319-329. Fasshauer, M....

  10. Napoleon in isolation

    OpenAIRE

    Calegari, Danny

    1999-01-01

    Napoleon's theorem in elementary geometry describes how certain linear operations on plane polygons of arbitrary shape always produce regular polygons. More generally, certain triangulations of a polygon that tiles R^2 admit deformations which keep fixed the symmetry group of the tiling. This gives rise to isolation phenomena in cusped hyperbolic 3-manifolds, where hyperbolic Dehn surgeries on some collection of cusps leaves the geometric structure at some other collection of cusps unchanged.

  11. Isolated unilateral disk edema

    OpenAIRE

    Varner P

    2011-01-01

    Paul VarnerJohn J Pershing VAMC, Poplar Bluff, MO, USAAbstract: Isolated unilateral disk edema is a familiar clinical presentation with myriad associations. Related, non-consensus terminology is a barrier to understanding a common pathogenesis. Mechanisms for the development of disk edema are reviewed, and a new framework for clinical differentiation of medical associations is presented.Keywords: disk edema, axoplasmic flow, clinical multiplier, optic neuritis, ischemic optic neuropathy, papi...

  12. Isolated Pulmonary Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Hatamizadeh

    2009-06-01

    Full Text Available Infective endocarditis is one of the most severe complications of parenteral drug abuse. The outstanding clinical feature of infective endocarditis in intravenous drug abusers is the high incidence of right-sided valve infection, and the tricuspid valve is involved in 60% to 70% of the cases. We herein report a case of isolated pulmonic valve infective endocarditis with a native pulmonary valve.

  13. Mechanical beam isolator

    International Nuclear Information System (INIS)

    Back-reflections from a target, lenses, etc. can gain energy passing backwards through a laser just like the main beam gains energy passing forwards. Unless something blocks these back-reflections early in their path, they can seriously damage the laser. A Mechanical Beam Isolator is a device that blocks back-reflections early, relatively inexpensively, and without introducing aberrations to the laser beam

  14. Beyond Insulation and Isolation

    DEFF Research Database (Denmark)

    Højlund, Marie Koldkjær

    2016-01-01

    insulation and isolation strategies to reduce measurable and perceptual noise levels. However, these strategies are unsuited to support the need to feel as an integral part of the shared hospital environment. This article suggests that the gap is intimately linked to a reductionist framework underlying the......Most research on the acoustic environment in the Western modern hospital identifies raised noise levels as the main causal explanation for the ranking of noise as critical stressors for patients, relatives and staffs. Therefore the most widely used strategies to tackle the problem in practice are...

  15. NORMOLIPEMIC ISOLATED XANTHOMA

    Directory of Open Access Journals (Sweden)

    Gowri Sankar

    2013-10-01

    Full Text Available ABSTRACT: Xanthomas are often a manifestation of underlying lipid abnormalities.A 17 - year - old female presented to our hospital with pain and swelling over t he left knee joint.Routine investigations and lipid profile were normal. Dermatological examination and Psychiatric examination were done and found to be normal. Histopathology from the lesion revealed macrophages and Touton type of giant cells. We present a case of normolipemic isolated xanthoma, which not only is an an uncommon occurrence but also needs a regular follow up because a high association with reticuloendothelial malignancies has also been reported.

  16. Diabetes in Population Isolates

    DEFF Research Database (Denmark)

    Grarup, Niels; Moltke, Ida; Albrechtsen, Anders;

    2016-01-01

    Type 2 diabetes (T2D) is an increasing health problem worldwide with particularly high occurrence in specific subpopulations and ancestry groups. The high prevalence of T2D is caused both by changes in lifestyle and genetic predisposition. A large number of studies have sought to identify...... on glucose-stimulated plasma glucose, serum insulin levels, and T2D. The variant defines a specific subtype of non-autoimmune diabetes characterized by decreased post-prandial glucose uptake and muscular insulin resistance. These and other recent findings in population isolates illustrate the value...

  17. Isolation of RNP granules

    DEFF Research Database (Denmark)

    Jønson, Lars; Nielsen, Finn Cilius; Christiansen, Jan

    2011-01-01

    be regarded as a supramolecular assembly of RNA and protein, probably representing several overlapping post-transcriptional operons. The present protocol describes how RNP granules may be isolated by the transgenic expression of a 3X FLAG version of an RNA-binding protein under tetracycline control...... via the tetracycline receptor/operator complex. In this way, inclusion of an appropriate tetracycline concentration ensures expression of the tagged version at the endogenous level, and the 3X FLAG tag is a convenient "handle" for the subsequent immunoprecipitation by immobilized anti-FLAG antibody....

  18. Journey from isolation

    Directory of Open Access Journals (Sweden)

    Wim A. Dreyer

    2011-06-01

    Full Text Available Since the Ottawa Consultation in 1982, the relationship between the Nederduitsch Hervormde Kerk van Afrika (NHKA and the World Alliance of Reformed Churches (WARC was nonexistent. In the NHKA it became progressively clear that it would be impossible to travel the road of faith alone. This article examined the factors which contributed to the growing isolation of the NHKA, especially nationalism, a particularistic ecclesiology and the rejection of Apartheid by international ecumenical bodies. It also reflected on efforts of the NHKA to return to the international ecumenical movement.

  19. How isolated is Antarctica?

    Science.gov (United States)

    Clarke, Andrew; Barnes, David K A; Hodgson, Dominic A

    2005-01-01

    The traditional view of Antarctica and the surrounding Southern Ocean as an isolated system is now being challenged by the recent discovery at the Antarctic Peninsula of adult spider crabs Hyas areneus from the North Atlantic and of larvae of subpolar marine invertebrates. These observations question whether the well described biogeographical similarities between the benthic fauna of the Antarctic Peninsula and the Magellan region of South America result from history (the two regions were once contiguous), or from a previously unrecognized low level of faunal exchange. Such exchange might be influenced by regional climate change, and also exacerbated by changes in human impact. PMID:16701330

  20. Schizosaccharomyces isolation method

    Directory of Open Access Journals (Sweden)

    Benito Santiago

    2014-01-01

    Full Text Available This study discusses the optimization of a selective and differential medium which would facilitate the isolation of Schizosaccharomyces (a genus with a low incidence compared to other microorganisms to select individuals from this genus for industrial purposes, especially in light of the recent recommendation of the use of yeasts from this genus in the wine industry by the International Organisation of Vine and Wine, or to detect the presence of such yeasts, for those many authors who consider them food spoilers. To this end, we studied various selective differential agents based on the main physiological characteristics of these species, such as their high resistances to high concentrations of sugar, sulfur dioxide, sorbic acid, benzoic acid, acetic acid or malo ethanolic fermentation. This selective medium is based on the genus resistance to the antibiotic actidione and its high resistance to inhibitory agents such as benzoic acid. Malic acid was used as a differential factor due to the ability of this genus to metabolise it to ethanol, which allows detecting of the degradation of this compound. Lastly, the medium was successfully used to isolate strains of Schizosaccharomyces pombe from honey and honeycombs.

  1. Identification of trans-sialidases as a common mediator of endothelial cell activation by African trypanosomes.

    Directory of Open Access Journals (Sweden)

    Zeinab Ammar

    Full Text Available Understanding African Trypanosomiasis (AT host-pathogen interaction is the key to an "anti-disease vaccine", a novel strategy to control AT. Here we provide a better insight into this poorly described interaction by characterizing the activation of a panel of endothelial cells by bloodstream forms of four African trypanosome species, known to interact with host endothelium. T. congolense, T. vivax, and T. b. gambiense activated the endothelial NF-κB pathway, but interestingly, not T. b. brucei. The parasitic TS (trans-sialidases mediated this NF-κB activation, remarkably via their lectin-like domain and induced production of pro-inflammatory molecules not only in vitro but also in vivo, suggesting a considerable impact on pathogenesis. For the first time, TS activity was identified in T. b. gambiense BSF which distinguishes it from the subspecies T. b. brucei. The corresponding TS were characterized and shown to activate endothelial cells, suggesting that TS represent a common mediator of endothelium activation among trypanosome species with divergent physiopathologies.

  2. Patients experience of source isolation

    DEFF Research Database (Denmark)

    Johansen, Kamilla; Pedersen, Didde; Kragbak, Nina;

    2013-01-01

    to the patients, and it is important to gain insight in the patients perspectives of being isolated, to develop treatment and caring strategies that may reduce the negative side effects of isolation. Aim: To make a systematic literature review, and analyse the literature to describe the state of the art knowledge...... and older and articles were peer reviewed. 11 articles were included and analysed by means of systematic text condensation. Results: Five themes were found; (1) Insufficient information, (2) Quality of care, (3) Physical environment, (4) Importance of relatives and (5) Psychological consequence....... The design of the ward with a balance between source isolation and visual and communicative opening to the outside is important to reduce the negative impact from isolation. Keywords: literature review, isolation, source isolation, patients experiences, patients perspectives, depression, coping, information...

  3. Isolation and the parish ministry

    OpenAIRE

    Irvine, Andrew R.

    1989-01-01

    The purpose of this thesis was to examine the concept of isolation as it occurs within the profession of ministry. Isolation, for the purpose of this thesis, is defined social-psychologically. Within the field research isolation is considered as evidenced professionally, socially and spiritually. This study utilized as its sample base 200 hundred Church of Scotland ministers (15% of total population) which provided 159 usable responses to an extensive mail survey. The mai...

  4. A hybrid base isolation system

    Energy Technology Data Exchange (ETDEWEB)

    Hart, G.C. [Univ. of California, Los Angeles, CA (United States); Lobo, R.F.; Srinivasan, M. [Hart Consultant Group, Santa Monica, CA (United States); Asher, J.W. [kpff Engineers, Santa Monica, CA (United States)

    1995-12-01

    This paper proposes a new analysis procedure for hybrid base isolation buildings when considering the displacement response of a base isolated building to wind loads. The system is considered hybrid because of the presence of viscous dampers in the building above the isolator level. The proposed analysis approach incorporates a detailed site specific wind study combined with a dynamic nonlinear analysis of the building response.

  5. Isolated Pelvic Hyperthermochemotherapeutic Perfusion -An Experimental Study on Isolating Efficacy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Hyperthermochemotherapeutic perfusion model through isolated pelvic vessels was developed to evaluate the leakage of hyperthermia and drugs (such as adriamycin) from the isolated pelvic circulation to systemic circulation and its associated side/toxic effects. The isolated pelvic circulation was perfused through a femoral artery catheter with hyperthermic (48 ℃ to 55 ℃) adriamycin solution (50 μg/ml) for 30 min. The efflux was drained through a femoral vein catheter. And the pelvic temperature was kept at the level of 43±0.5 ℃. The temperature of pelvic circulation was kept at 4 ℃ to 5 ℃ greater than the systemic/core temperature. The adriamycin concentration of pelvic efflux was 12 to 46 folds of that of systemic serum. The difference between them was very significant (P<0.001). As the perfusion pressure was increased, which kept lower than the mean systemic artery pressure, the leakage of the adriamycin from the isolated pelvic circulation to systemic circulation was increased, but there was no significant difference between them (P>0.05). During isolated perfusion, the systemic blood dynamics remained stable and there were no organic injuries on the important organs. It was suggested that the isolating efficacy of the modality of isolated pelvic hyperthermochemotherapeutic perfusion through vessels was rather high. The hyperthermia and drugs could be effectively limited in the isolated pelvic region with minor side effects on the systemic circulation and important organs.

  6. Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe

    CERN Document Server

    Argudo-Fernández, M; Bergond, G; Puertas, S Duarte; Carmona, E Ramos; Sabater, J; Lorenzo, M Fernández; Espada, D; Sulentic, J; Ruiz, J E; Leon, S

    2015-01-01

    The construction of catalogues of galaxies and the posterior study of galaxy properties in relation to their environment, have been hampered by the scarce redshift information. The new 3-dimensional (3D) surveys permits to distinguish small, faint, physically bound satellites from a background projected galaxy population, giving a more comprehensive 3D picture of the surroundings. We aim to provide representative samples of isolated galaxies, isolated pairs, and isolated triplets for testing galaxy evolution and secular processes in low density regions of the local Universe, as well as to characterise their local and large-scale environments. We use spectroscopic data from the SDSS to automatically and homogeneously compile catalogues of 3,702 isolated galaxies, 1,240 isolated pairs, and 315 isolated triplets in the local Universe. To quantify the effects of their local and large-scale environments, we compute the projected density and the tidal strength for the brightest galaxy in each sample. We find eviden...

  7. Seismic isolation for Advanced LIGO

    CERN Document Server

    Abbott, R; Allen, G; Cowley, S; Daw, E; Debra, D; Giaime, J; Hammond, G; Hammond, M; Hardham, C; How, J; Hua, W; Johnson, W; Lantz, B; Mason, K; Mittleman, R; Nichol, J; Richman, S; Rollins, J; Shoemaker, D; Stapfer, G; Stebbins, R

    2002-01-01

    The baseline design concept for a seismic isolation component of the proposed 'Advanced LIGO' detector upgrade has been developed with proof-of-principle experiments and computer models. It consists of a two-stage in-vacuum active isolation platform that is supported by an external hydraulic actuation stage. Construction is underway for prototype testing of a full-scale preliminary design.

  8. Improved Active Vibration Isolation Systems

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The control force, feedback gain, and actuator stroke of several active vibration isolation systems were analyzed based on a single-layer active vibration isolation system. The analysis shows that the feedback gain and actuator stroke cannot be selected independently and the active isolation system design must make a compromise between the feedback gain and actuator stroke. The performance of active isolation systems can be improved by the joint vibration reduction using an active vibration isolation system with an adaptive dynamic vibration absorber. The results show that the joint vibration reduction method can successfully avoid the compromise between the feedback gain and actuator stroke. The control force and the object vibration amplitude are also greatly reduced.

  9. Isolation of rat adrenocortical mitochondria

    International Nuclear Information System (INIS)

    Highlights: ► A method for isolation of adrenocortical mitochondria from the adrenal gland of rats is described. ► The purified isolated mitochondria show excellent morphological integrity. ► The properties of oxidative phosphorylation are excellent. ► The method increases the opportunity of direct analysis of adrenal mitochondria from small animals. -- Abstract: This report describes a relatively simple and reliable method for isolating adrenocortical mitochondria from rats in good, reasonably pure yield. These organelles, which heretofore have been unobtainable in isolated form from small laboratory animals, are now readily accessible. A high degree of mitochondrial purity is shown by the electron micrographs, as well as the structural integrity of each mitochondrion. That these organelles have retained their functional integrity is shown by their high respiratory control ratios. In general, the biochemical performance of these adrenal cortical mitochondria closely mirrors that of typical hepatic or cardiac mitochondria.

  10. Isolation of methylglyoxal from liver.

    Science.gov (United States)

    Fodor, G; Mujumdar, R; Szent-Gyorgyi, A

    1978-01-01

    Acetaldehyde and methylglyoxal were shown to be present in liver bound to protein. They were isolated in the form of 2,4-dinitrophenylhydrazones and osazones, respectively. The NMR spectrum of pure methylglyoxal was recorded. PMID:279916

  11. Isolation of rat adrenocortical mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Solinas, Paola [Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Department of Medicine, Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Fujioka, Hisashi [Electron Microscopy Facility, Department of Pharmacology, Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Tandler, Bernard [Department of Biological Sciences, School of Dental Medicine, Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Hoppel, Charles L., E-mail: charles.hoppel@case.edu [Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States); Department of Medicine, Center for Mitochondrial Disease, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States)

    2012-10-12

    Highlights: Black-Right-Pointing-Pointer A method for isolation of adrenocortical mitochondria from the adrenal gland of rats is described. Black-Right-Pointing-Pointer The purified isolated mitochondria show excellent morphological integrity. Black-Right-Pointing-Pointer The properties of oxidative phosphorylation are excellent. Black-Right-Pointing-Pointer The method increases the opportunity of direct analysis of adrenal mitochondria from small animals. -- Abstract: This report describes a relatively simple and reliable method for isolating adrenocortical mitochondria from rats in good, reasonably pure yield. These organelles, which heretofore have been unobtainable in isolated form from small laboratory animals, are now readily accessible. A high degree of mitochondrial purity is shown by the electron micrographs, as well as the structural integrity of each mitochondrion. That these organelles have retained their functional integrity is shown by their high respiratory control ratios. In general, the biochemical performance of these adrenal cortical mitochondria closely mirrors that of typical hepatic or cardiac mitochondria.

  12. Isolated tubercles of some Palaeoscolecida

    NARCIS (Netherlands)

    Boogaard, van den M.

    1989-01-01

    Tubercles of Palaeoscolex? tenensis Kraft & Mergl, 1989 found as isolated phosphatic microfossils in Ordovician limestones are described. The probability that the phosphatic microfossils assigned to the genera Hadimopanella Gedik, 1977 and Milaculum Müller, 1973 represent tubercles of palaeoscolecid

  13. Missed isolated posterior malleolar fractures

    OpenAIRE

    Ozler, Turhan; Guven, Melih; Onal, Ayberk; Ulucay, Cagatay; Beyzadeoglu, Tahsin; Altintas, Faik

    2014-01-01

    Objective:The aim of this study was to evaluate the injury mechanism and clinical and radiological results of the patients with isolated posterior malleolar fracture.Methods: Seven patients (5 male, 2 female; mean age: 32 years; range: 23-40) with a missed isolated posterior malleolar fracture were included in the study. All patients had initially been examined for an ankle sprain in the emergency room, where the initial plain radiographs did not show any abnormality. Due to the long lasting ...

  14. Pneumothorax complicating isolated clavicle fracture.

    Science.gov (United States)

    Hani, Redouane; Ennaciri, Badr; Jeddi, Idriss; El Bardouni, Ahmed; Mahfoud, Mustapha; Berrada, Mohamed Saleh

    2015-01-01

    Isolated clavicle fractures are among the commonest of traumatic fractures in the emergency department. Complications of isolated clavicle fractures are rare. Pneumothorax has been described as a complication of a fractured clavicle only rarely in English literature. In all the reported cases, the pneumothorax was treated by a thoracostomy and the clavicle fracture was treated conservatively. In our case, the pneumothorax required a chest drain insertion and the clavicle fracture was treated surgically with good result.

  15. Base isolation of fluid containers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. [Cygna Group Inc./ICF Kaiser International, Oakland, CA (United States)

    1995-12-01

    Fluid containers often constitute critical internal equipment in power plants. However, due to possible structure-equipment interaction effect they are particularly vulnerable during strong earthquake events. An effective technique for protecting fluid containers is base isolation. By deflecting the possible seismic input energy into the superstructure, base isolation can substantially reduce seismic demand on the containers, making it more cost effective than equivalent conventional design.

  16. Base isolation of fluid containers

    International Nuclear Information System (INIS)

    Fluid containers often constitute critical internal equipment in power plants. However, due to possible structure-equipment interaction effect they are particularly vulnerable during strong earthquake events. An effective technique for protecting fluid containers is base isolation. By deflecting the possible seismic input energy into the superstructure, base isolation can substantially reduce seismic demand on the containers, making it more cost effective than equivalent conventional design

  17. Geomorphology of Minnesota - Isolated Landform Structures

    Data.gov (United States)

    Minnesota Department of Natural Resources — Geomorphology of Minnesota - Isolated Landform Structures are essentially cartographic arcs representing isolated glacial features that were mapped in conjunction...

  18. Isolation and identification of local Bacillus isolates for xylanase biosynthesis.

    Directory of Open Access Journals (Sweden)

    Hassan Ammoneh

    2014-04-01

    Full Text Available Bacillus species are attractive industrial organisms due to their rapid growth rates leading to a short fermentation cycle and for their capacity to secrete important enzymes and proteins such as xylanase into the extracellular medium. Considering the industrial importance of xylanase, in this current study, Bacillus spp. were isolated from different soils and were screened for their xylanase production.Bacillus isolates used in this study were obtained from a national screening program carried out during 2006-2007 in which soil samples that covered areas throughout the interior of Syria were collected. The prepared inoculum from each of Bacillus isolates was aliquoted onto xylan agar plates, incubated at 30°C for 72 h and screened for xylanase synthesis.Xylanolytic isolates were selected depending on the clear zones of xylan hydrolysis. Fifteen isolates having the highest clearing zone were determined and grown in a solid state fermentation. Of the 15 isolates, three bacilli namely SY30A, SY185C and SY190E that showed maximum xylanase production, were identified using the 16S rDNA sequencing method. According to 16S rDNA gene sequence data, the closest phylogenetic neighbor for SY30A was Bacillus pumilus and for SY185C and SY190E isolates was Bacillus subtilis. Optimal pH and temperature for xylanase activity was 7.0 and 55ºC for SY30A and 6.0 and 60ºC for SY185C and SY190E, respectively. Under these conditions, the following activities were found to be around 1157 ± 58, 916 ± 46 and 794 ± 39 (U/g for SY30A, SY185C and SY190E, respectivly.Selected local Bacillus isolates were found to be a potential source of xylanase which was proven to be quite suitable for multiple biotechnological applications. These isolates might after extensive optimization steps be an alternative to commercially available strains.

  19. Catalogues of isolated galaxies, isolated pairs, and isolated triplets in the local Universe

    Science.gov (United States)

    Argudo-Fernández, M.; Verley, S.; Bergond, G.; Duarte Puertas, S.; Ramos Carmona, E.; Sabater, J.; Fernández Lorenzo, M.; Espada, D.; Sulentic, J.; Ruiz, J. E.; Leon, S.

    2015-06-01

    Context. The construction of catalogues of galaxies and the a posteriori study of galaxy properties in relation to their environment have been hampered by scarce redshift information. The new 3-dimensional (3D) surveys permit small, faint, physically bound satellites to be distinguished from a background-projected galaxy population, giving a more comprehensive 3D picture of the surroundings. Aims: We aim to provide representative samples of isolated galaxies, isolated pairs, and isolated triplets for testing galaxy evolution and secular processes in low density regions of the local Universe, as well as to characterise their local and large-scale environments. Methods: We used spectroscopic data from the tenth data release of the Sloan Digital Sky Survey (SDSS-DR10) to automatically and homogeneously compile catalogues of 3702 isolated galaxies, 1240 isolated pairs, and 315 isolated triplets in the local Universe (z ≤ 0.080). To quantify the effects of their local and large-scale environments, we computed the projected density and the tidal strength for the brightest galaxy in each sample. Results: We find evidence of isolated pairs and isolated triplets that are physically bound at projected separations up to d ≤ 450 kpc with radial velocity difference Δν ≤ 160 km s-1, where the effect of the companion typically accounts for more than 98% of the total tidal strength affecting the central galaxy. For galaxies in the catalogues, we provide their positions, redshifts, and degrees of relation with their physical and large-scale environments. The catalogues are publicly available to the scientific community. Conclusions: For isolated galaxies, isolated pairs, and isolated triplets, there is no difference in their degree of interaction with the large-scale structure (up to 5 Mpc), which may suggest that they have a common origin in their formation and evolution. We find that most of them belong to the outer parts of filaments, walls, and clusters, and generally

  20. Perceived social isolation and cognition.

    Science.gov (United States)

    Cacioppo, John T; Hawkley, Louise C

    2009-10-01

    Social species, from Drosophila melanogaster to Homo sapiens, fare poorly when isolated. Homo sapiens, an irrepressibly meaning-making species, are, in normal circumstances, dramatically affected by perceived social isolation. Research indicates that perceived social isolation (i.e. loneliness) is a risk factor for, and may contribute to, poorer overall cognitive performance, faster cognitive decline, poorer executive functioning, increased negativity and depressive cognition, heightened sensitivity to social threats, a confirmatory bias in social cognition that is self-protective and paradoxically self-defeating, heightened anthropomorphism and contagion that threatens social cohesion. These differences in attention and cognition impact on emotions, decisions, behaviors and interpersonal interactions that can contribute to the association between loneliness and cognitive decline and between loneliness and morbidity more generally. PMID:19726219

  1. VIBRATION ISOLATION SYSTEM PROBABILITY ANALYSIS

    Directory of Open Access Journals (Sweden)

    Smirnov Vladimir Alexandrovich

    2012-10-01

    Full Text Available The article deals with the probability analysis for a vibration isolation system of high-precision equipment, which is extremely sensitive to low-frequency oscillations even of submicron amplitude. The external sources of low-frequency vibrations may include the natural city background or internal low-frequency sources inside buildings (pedestrian activity, HVAC. Taking Gauss distribution into account, the author estimates the probability of the relative displacement of the isolated mass being still lower than the vibration criteria. This problem is being solved in the three dimensional space, evolved by the system parameters, including damping and natural frequency. According to this probability distribution, the chance of exceeding the vibration criteria for a vibration isolation system is evaluated. Optimal system parameters - damping and natural frequency - are being developed, thus the possibility of exceeding vibration criteria VC-E and VC-D is assumed to be less than 0.04.

  2. Bacteria isolated from amoebae/bacteria consortium

    Science.gov (United States)

    Tyndall, Richard L.

    1995-01-01

    New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

  3. Is an isolated cleft lip an isolated anomaly?

    NARCIS (Netherlands)

    Deelder, J. D.; Breugem, C. C.; de Vries, Iris; de Bruin, M.; van der Molen, A. B. Mink; van der Horst, C. M. A. M.

    2011-01-01

    Introduction: It is well known that patients with cleft lip/palate or cleft palate can have associated anomalies. However, there is a relative paucity of information about the possible anomalies associated with an isolated cleft lip. A recent study (Vallino et al., 2008) showed that children with cl

  4. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated......Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...

  5. Isolated complete corpus callosal agenesis

    Directory of Open Access Journals (Sweden)

    Jaiganesh S, Venkateshwaran A, Naresh Kumar C, Rajasekhar KV

    2014-11-01

    Full Text Available Isolated complete corpus callosal agenesis is a rare entity. Usually this condition will be an associated finding in other syndromes. 3 month old male child came with complaints of deformed foot on both sides, not having a social smile and neck holding. Patient referred to the Radiology department for MRI brain which showed complete absence of corpus callosum, widely separated and parallely placed lateral ventricles, colpocephaly, high riding of 3rd ventricle and absence of cingulate gyrus and radial arrangement of gyri along the interhemispheric fissure. Hence it was reported as isolated complete corpus callosal agenesis and this article describes the Embryogenesis, anatomy, developmental anomalies and its clinical manifestations & prognosis.

  6. [Isolated giant hydatid in kidney].

    Science.gov (United States)

    Ozgör, Faruk; Erbin, Akif; Berberoğlu, Ahmet Yalçın; Binbay, Murat; Sarılar, Omer; Müslümanoğlu, Ahmet Yaser

    2014-06-01

    Cyst hydatid of the kidney is parasitic condition caused by Echinococcus granulosus and identified in many countries, especially associated with sheep farming. Echinococcal larvae enter the bloodstream using the digestive system and invade any organs in the human body. The urinary system is the third most common area affected by parasitic infection after liver and lungs, but isolated renal involvement is a very rare situation, even in endemic areas. İn our case, we aimed to report a 57-year-old female patient with an 18-centimeter isolated renal cyst hydatid treated by retroperitoneal nephrectomy. The diagnosis was based on imaging findings and confirmed by histopathologically.

  7. Database Replication Using Generalized Snapshot Isolation

    OpenAIRE

    Elnikety, Sameh; Pedone, Fernando; Zwaenepoel, Willy

    2005-01-01

    Generalized snapshot isolation extends snapshot isolation as used in Oracle and other databases in a manner suitable for replicated databases. While (conventional) snapshot isolation requires that transactions observe the “latest” snapshot of the database, generalized snapshot isolation allows the use of “older” snapshots, facilitating a replicated implementation. We show that many of the desirable properties of snapshot isolation remain. In particular, read-only transactions never block or a...

  8. Effectiveness of Base Isolation Technique and Influence of Isolator Characteristics on Response of a Base Isolated Building

    Directory of Open Access Journals (Sweden)

    Sunita Tolani

    2016-06-01

    Full Text Available This study concerns with the seismic response comparison of a fixed base building with a base isolated building and parametric study of a base isolated building. The structural system considered for analysis is a three storey reinforced concrete building, which is idealized as a shear type building with one lateral degree of freedom at each floor level. The isolation systems considered for this study are Laminated Rubber bearing (LRB, Lead Rubber Bearing (N-Z bearing and Friction Pendulum System (FPS. The response of fixed base building and of base isolated building is compared in terms of maximum top floor acceleration, interstorey drift, maximum floor displacements and base shear. For parametric study important isolation system parameters considered are: (i isolation time period, isolator damping for LRB; (ii isolator yield strength, isolation time period, isolator damping for N-Z bearing and (iii isolation time period, friction coefficient for FPS. It is found that base isolation technique is very effective in reducing seismic response of structure and isolation system parameters significantly influence the earthquake response of a base isolated structure.

  9. Pediatric isolated bilateral iliac aneurysm.

    Science.gov (United States)

    Chithra, R; Sundar, R Ajai; Velladuraichi, B; Sritharan, N; Amalorpavanathan, J; Vidyasagaran, T

    2013-07-01

    Aneurysms are rare in children. Isolated iliac artery aneurysms are very rare, especially bilateral aneurysms. Pediatric aneurysms are usually secondary to connective tissue disorders, arteritis, or mycotic causes. We present a case of a 3-year-old child with bilateral idiopathic common iliac aneurysms that were successfully repaired with autogenous vein grafts.

  10. Isolation of mitochondria from CNS

    OpenAIRE

    Kristian, Tibor

    2010-01-01

    This unit contains a protocol describing the isolation of brain mitochondria by using discontinuous Percoll gradient centrifugation. The Percoll density gradient centrifugation separates synaptosomes, myelin, and free non-synaptic mitochondria released from cells during tissue homogenization into individual fractions. Mitochondria entrapped in synaptosomes (synaptic mitochondria) can be liberated using nitrogen cavitation and then further purified by Percoll gradient centrifugation. These met...

  11. Emotional isolation in BBC Forum

    International Nuclear Information System (INIS)

    We analyze emotionally annotated massive data from BBC Forum and examine properties of the isolation phenomenon of negative and positive users. Our results show the existence of a percolation threshold dependent on the average emotional value in the network of negatively charged nodes

  12. High-Voltage Isolation Transformer

    Science.gov (United States)

    Clatterbuck, C. H.; Ruitberg, A. P.

    1985-01-01

    Arcing and field-included surface erosion reduced by electrostatic shields around windings and ferromagnetic core of 80-kilovolt isolation transformer. Fabricated from high-resistivity polyurethane-based material brushed on critical surfaces, shields maintained at approximately half potential difference of windings.

  13. Providencia stuartii Isolates from Greece

    NARCIS (Netherlands)

    Oikonomou, Olga; Liakopoulos, Apostolos; Phee, Lynette M.; Betts, Jonathan; Mevius, Dik; Wareham, David W.

    2016-01-01

    Providencia stuartii has emerged as an important nosocomial pathogen. We describe an outbreak due to a multidrug-resistant strain over a 4-month period in a critical care unit in Athens. Molecular typing revealed each of the isolates to be clonally related with coresistance to cephalosporins, car

  14. Isolated tubercles of some Palaeoscolecida

    OpenAIRE

    Boogaard, van den, F.E.

    1989-01-01

    Tubercles of Palaeoscolex? tenensis Kraft & Mergl, 1989 found as isolated phosphatic microfossils in Ordovician limestones are described. The probability that the phosphatic microfossils assigned to the genera Hadimopanella Gedik, 1977 and Milaculum Müller, 1973 represent tubercles of palaeoscolecidans is discussed. A relation between Palaeoscolecida and Chordata is hinted at.

  15. Isolation and identification among cockle isolates of Vibrio vulnificus isolated from Selangor, Malaysia

    Science.gov (United States)

    Kurdi Al-Dulaimi, Mohammed M.; Mutalib, Sahilah Abd.; Ghani, Ma`aruf Abd.

    2014-09-01

    Vibrio vulnificus infections are worldwide public health problems associated with illnesses resulting from consumption of raw or partially cooked seafood. The aim of this study was to investigate the presence and identification of V. vulnificus in cockles from local wet (40) and supermarkets (38) from Selangor, Malaysia from July 2013 to February 2014. A total of 78(n=78) cockle were examined for the presence of V. vulnificus and at about 32% (25/78) cockle samples were positive to this bacterium. Colonies morphological observation and biochemical characterization for those isolates showed 60% (15/78) of isolates were classified as biotype 1 and 40% (10/78) belong to biotype 2.

  16. Identification of different trypanosome species in the mid-guts of tsetse flies of the Malanga (Kimpese sleeping sickness focus of the Democratic Republic of Congo

    Directory of Open Access Journals (Sweden)

    Simo Gustave

    2012-09-01

    Full Text Available Abstract Background The Malanga sleeping sickness focus of the Democratic Republic of Congo has shown an epidemic evolution of disease during the last century. However, following case detection and treatment, the prevalence of the disease decreased considerably. No active survey has been undertaken in this focus for a couple of years. To understand the current epidemiological status of sleeping sickness as well as the animal African trypanosomiasis in the Malanga focus, we undertook the identification of tsetse blood meals as well as different trypanosome species in flies trapped in this focus. Methods Pyramidal traps were use to trap tsetse flies. All flies caught were identified and live flies were dissected and their mid-guts collected. Fly mid-gut was used for the molecular identification of the blood meal source, as well as for the presence of different trypanosome species. Results About 949 Glossina palpalis palpalis were trapped; 296 (31.2% of which were dissected, 60 (20.3% blood meals collected and 57 (19.3% trypanosome infections identified. The infection rates were 13.4%, 5.1%, 3.5% and 0.4% for Trypanosoma congolense savannah type, Trypanosoma brucei s.l., Trypanosoma congolense forest type and Trypanosoma vivax, respectively. Three mixed infections including Trypanosoma brucei s.l. and Trypanosoma congolense savannah type, and one mixed infection of Trypanosoma vivax and Trypanosoma congolense savannah type were identified. Eleven Trypanosoma brucei gambiense infections were identified; indicating an active circulation of this trypanosome subspecies. Of all the identified blood meals, about 58.3% were identified as being taken on pigs, while 33.3% and 8.3% were from man and other mammals, respectively. Conclusion The presence of Trypanosoma brucei in tsetse mid-guts associated with human blood meals is indicative of an active transmission of this parasite between tsetse and man. The considerable number of pig blood meals combined

  17. Vapor-barrier Vacuum Isolation System

    Science.gov (United States)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

    2014-01-01

    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  18. Isolated Proofs of Knowledge and Isolated Zero Knowledge

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Nielsen, Jesper Buus; Wichs, Daniel

    2008-01-01

    We consider proof of knowledge protocols where the cheating prover may communicate with some external adversarial environment during the run of the proof. Without additional setup assumptions, no witness hiding protocol can securely ensure that the prover knows a witness in this scenario...... notion called ℓ-isolated proofs of knowledge (ℓ-IPoK). These protocols securely ensure that an ℓ-isolated prover knows the witness. To prevent the above-mentioned attack, an ℓ-IPoK protocol has to have communication complexity greater than ℓ. We show that for any relation in NP and any value ℓ......, there is an ℓ-IPoK protocol for that relation. In addition, the communication complexity of such a protocol only needs to be larger than ℓ by a constant multiplicative factor....

  19. The detection and treatment of human African trypanosomiasis

    Directory of Open Access Journals (Sweden)

    Bouteille B

    2012-06-01

    Full Text Available Bernard Bouteille,1 Alain Buguet21Laboratory of Parasitology, Dupuytren University Hospital of Limoges, France; 2Polyclinic Marie-Louise Poto-Djembo, Pointe-Noire, CongoAbstract: Human African trypanosomiasis (HAT is caused by the injection of Trypanosoma brucei (T. b. gambiense or T. b. rhodesiense by Glossina, the tsetse fly. Three historical eras followed the exclusive clinical approach of the 19th century. At the turn of the century, the “initial research” era was initiated because of the dramatic spread of HAT throughout intertropical Africa, and scientists discovered the agent and its vector. Two entities, recurrent fever and sleeping sickness, were then considered a continuum between hemolymphatic stage 1 and meningoencephalitic stage 2. Treatments were developed. Soon after World War I, specific services and mobile teams were created, initiating the “epidemiological” era, during which populations were visited, screened, and treated. As a result, by 1960, annual new cases were rare. New mass screening and staging tools were then developed in a third, “modern” era, especially to counter a new epidemic wave. Currently, diagnosis still relies on microscopic detection of trypanosomes without (wet and thick blood films or with concentration techniques (capillary tube centrifugation, miniature anion-exchange centrifugation technique. Staging is a vital step.Stage 1 patients are treated on site with pentamidine or suramin. However, stage 2 patients are treated in specialized facilities, using drugs that are highly toxic and/or that require complex administration procedures (melarsoprol, eflornithine, or nifurtimox-eflornithine combination therapy. Suramin and melarsoprol are the only medications active against Rhodesian HAT. Staging still relies on cerebrospinal fluid examination for trypanosome detection and white blood cell counts: stage 1, absence of trypanosomes, white blood cell counts ≤ 5/µL; stage 2, presence of

  20. Immunodiagnosis of bovine trypanosomiasis in Anambra and Imo states, Nigeria, using enzyme-linked immunosorbent assay: zoonotic implications to human health

    Directory of Open Access Journals (Sweden)

    M.C. Ezeani

    2008-11-01

    Full Text Available Background & objectives: The prevalence of trypanosomiasis was studied in cattle, being a major source of animal protein in Nigeria, thus, a very likely means of spread of Human African Trypano-somosis (HAT. Methods: Enzyme-linked immunosorbent assay (ELISA was used to diagnose bovine trypanosomiasis in 264 samples collected from adult cattle of mixed breeds, age and sex, in Anambra and Imo states, Nigeria. Results: Out of 264 samples analysed, 21 (7.96% were seropositive for Trypanosoma congolense while 20 (7.58% were seropositive for T. vivax and 8 (3.03% were seropositive for T. brucei infections in both the states. Interpretation & conclusion: The predominant species was found to be T. congolense. Mixed infection of three species, T. vivax, T. congolense and T. brucei was found to dominate other mixed infections in both the states. ELISA detected the infection of the three species of trypanosomes in the same group of animals. The usefulness of antigen capture ELISA in the diagnosis of human or animal trypanosomiasis was established, and the possibility of the spread of HAT caused by T. brucei gambiense and T.b. rhodesiense through cattle was expressed.

  1. Sympathicotomy for isolated facial blushing

    DEFF Research Database (Denmark)

    Licht, Peter Bjørn; Pilegaard, Hans K; Ladegaard, Lars

    2012-01-01

    Background. Facial blushing is one of the most peculiar of human expressions. The pathophysiology is unclear, and the prevalence is unknown. Thoracoscopic sympathectomy may cure the symptom and is increasingly used in patients with isolated facial blushing. The evidence base for the optimal level...... of targeting the sympathetic chain is limited to retrospective case studies. We present a randomized clinical trial. Methods. 100 patients were randomized (web-based, single-blinded) to rib-oriented (R2 or R2-R3) sympathicotomy for isolated facial blushing at two university hospitals during a 6-year period...... in all social and mental domains in both groups. Overall, 85% of the patients had an excellent or satisfactory result, with no significant difference between the R2 procedure and the R2-R3 procedure. Mild recurrence of facial blushing occurred in 30% of patients within the first year. One patient...

  2. Heterogeneity of koala retrovirus isolates.

    Science.gov (United States)

    Shimode, Sayumi; Nakagawa, So; Yoshikawa, Rokusuke; Shojima, Takayuki; Miyazawa, Takayuki

    2014-01-01

    Koala retrovirus (KoRV) is a gammaretrovirus which may induce immune suppression, leukemia and lymphoma in koalas. Currently three KoRV subgroups (A, B, and J) have been reported. Our phylogenetic analysis suggests that KoRV-B and KoRV-J should be classified as the same subgroup. In long terminal repeat (LTR), a KoRV-B isolate has four 17 bp tandem repeats named direct repeat (DR)-1, while a KoRV-J isolate (strain OJ-4) has three 37 bp tandem repeats named DR-2. We also found that the promoter activity of the KoRV-J strain OJ-4 is stronger than that of original KoRV-A, suggesting that KoRV-J may replicate more efficiently than KoRV-A.

  3. Autosomal dominant isolated ('uncomplicated') microcephaly.

    OpenAIRE

    Merlob, P; Steier, D; Reisner, S H

    1988-01-01

    A large family (13 affected members in three generations) is reported in which isolated microcephaly occurred without any other dysmorphic or neurological abnormalities. The family pedigree confirms the autosomal dominant mode of inheritance with incomplete penetrance, including one example of male to male transmission and the occurrence of a non-manifesting heterozygote resulting in a 'skipped generation'. There is considerable variation in the phenotypic expression of autosomal dominant mic...

  4. Transformerless dc-Isolated Converter

    Science.gov (United States)

    Rippel, Wally E.

    1987-01-01

    Efficient voltage converter employs capacitive instead of transformer coupling to provide dc isolation. Offers buck/boost operation, minimal filtering, and low parts count, with possible application in photovoltaic power inverters, power supplies and battery charges. In photovoltaic inverter circuit with transformerless converter, Q2, Q3, Q4, and Q5 form line-commutated inverter. Switching losses and stresses nil because switching performed when current is zero.

  5. Protein isolation using affinity chromatography

    OpenAIRE

    Besselink, T.

    2012-01-01

    Many product or even waste streams in the food industry contain components that may have potential for e.g. functional foods. These streams are typically large in volume and the components of interest are only present at low concentrations. A robust and highly selective separation process should be developed for efficient isolation of the components. Affinity chromatography is such a selective method. Ligands immobilized to a stationary phase (e.g., a resin or membrane) are used to bind the c...

  6. Fungi isolated in school buildings

    OpenAIRE

    Elżbieta Ejdys

    2013-01-01

    The aim of the study was to determine the species composition of fungi occurring on wall surfaces and in the air in school buildings. Fungi isolated from the air using the sedimentation method and from the walls using the surface swab technique constituted the study material. Types of finish materials on wall surfaces were identified and used in the analysis. Samples were collected in selected areas in two schools: classrooms, corridors, men's toilets and women's toilets, cloakrooms, sports c...

  7. Isolation and Aggregation in Economics

    OpenAIRE

    Schlicht, Ekkehart

    1985-01-01

    In explaining economic phenomena, economic analysis concentrates on selected influences and fixes the host of other factors under a ceteris paribus clause. This view, which goes back to Alfred Marshall (1842-1924), is developed in the first part of the book. Aggregation is viewed as a particular application of ceteris paribus analysis - isolation from "structural effects". This leads to an approach, called "closed aggregation", which was introduced by Kenneth May and is also implicit in Keyne...

  8. Tiamulin resistance in porcine Brachyspira pilosicoli isolates.

    Science.gov (United States)

    Pringle, M; Landén, A; Franklin, A

    2006-02-01

    There are few studies on antimicrobial susceptibility of Brachyspira pilosicoli, therefore this study was performed to investigate the situation among isolates from pigs. The tiamulin and tylosin susceptibility was determined by broth dilution for 93 and 86 porcine B. pilosicoli isolates, respectively. The isolates came from clinical samples taken in Swedish pig herds during the years 2002 and 2003. The tylosin minimal inhibitory concentration (MIC) was >16 microg/ml for 50% (n=43) of the isolates tested. A tiamulin MIC >2 microg/ml was obtained for 14% (n=13) of the isolates and these were also tested against doxycycline, salinomycin, valnemulin, lincomycin and aivlosin. For these isolates the susceptibility to salinomycin and doxycycline was high but the MICs for aivlosin varied. The relationship between the 13 tiamulin resistant isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Among the 13 isolates 10 different PFGE patterns were identified.

  9. Mycoplasma contamination of Chlamydia pneumoniae isolates

    DEFF Research Database (Denmark)

    Huniche, BS; Jensen, Lise Torp; Birkelund, Svend;

    1998-01-01

    We examined 6 C. pneumonia isolates from The American Type Culture Collection (ATCC) and 2 Finnish isolates for Mycoplasma contamination. Three of the ATCC isolates and both of the Finnish isolates were Mycoplasma-contaminated. The contaminants were characterized by means of growth in BEa and BEg...... media, immunoblotting, polymerase chain reaction and pulsed field gel electrophoresis. Two of the 6 ATCC isolates [ATCC VR1355 (TWAR strain 2043) and ATCC VR1356 (TWAR strain 2023)] were infected with Mycoplasma hominis and 1 isolate [ATCC VR2282 (TWAR strain TW183)] was contaminated with both...... Mycoplasma hominis and Mycoplasma orale, whereas 3 of the ATCC isolates [ATCC VR1310, ATCC VR1360 (TWAR strain CM-1) and ATCC 53592 (TWAR strain AR39)] were not contaminated. The Finnish C. pneumoniae isolates Kajaani 6 and Parola were found to be contaminated with M. hominis and M. orale, respectively...

  10. Isolated malignant melanoma metastasis to the pancreas

    DEFF Research Database (Denmark)

    Larsen, Anne K; Krag, Christen; Geertsen, Poul;

    2013-01-01

    SUMMARY: Malignant melanomas rarely develop isolated pancreatic metastases. We describe a unique patient who is still alive 22 years following an isolated pancreatic melanoma metastasis, and we review the sparse literature in the field....

  11. Isolation of haloorganic groundwater humic substances

    DEFF Research Database (Denmark)

    Krog, M.; Grøn, C.

    1995-01-01

    Humic substances were isolated from groundwater according to a revised method designed to avoid organohalogen artefacts. The prepared humic substances exhibited lower halogen contents than humic substances isolated according to the conventionally used method. Excessive oxidation or hydrolysis...

  12. Input-output rearrangement of isolated converters

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Kovacevic, Milovan; Mønster, Jakob Døllner;

    2015-01-01

    This paper presents a new way of rearranging the input and output of isolated converters. The new arrangement posses several advantages, as increased voltage range, higher power handling capabilities, reduced voltage stress and improved efficiency, for applications where galvanic isolation...

  13. Vibrio cholerae O1 isolated in Kenya.

    OpenAIRE

    Iwanaga, M; Mori, K.; Kaviti, J N

    1982-01-01

    Biological and serological analyses of 272 isolates of Vibrio cholerae O1 from six epidemics and from a few sporadic cases in Kenya were carried out. All of the isolates were identified as V. cholerae biotype E1 Tor, and 210 out of 272 isolates were hemolytic as examined by Feeley's method.

  14. Fungi isolated in school buildings

    Directory of Open Access Journals (Sweden)

    Elżbieta Ejdys

    2013-12-01

    Full Text Available The aim of the study was to determine the species composition of fungi occurring on wall surfaces and in the air in school buildings. Fungi isolated from the air using the sedimentation method and from the walls using the surface swab technique constituted the study material. Types of finish materials on wall surfaces were identified and used in the analysis. Samples were collected in selected areas in two schools: classrooms, corridors, men's toilets and women's toilets, cloakrooms, sports changing rooms and shower. Examinations were conducted in May 2005 after the heating season was over. Fungi were incubated on Czapek-Dox medium at three parallel temperatures: 25, 37 and 40°C, for at least three weeks. A total of 379 isolates of fungi belonging to 32 genera of moulds, yeasts and yeast-like fungi were obtained from 321 samples in the school environment. The following genera were isolated most frequently: Aspergillus, Penicillium and Cladosporium. Of the 72 determined species, Cladosporium herbarum, Aspergillus fumigatus and Penicillium chrysogenum occurred most frequently in the school buildings. Wall surfaces were characterised by an increased prevalence of mycobiota in comparison with the air in the buildings, with a slightly greater species diversity. A certain species specificity for rough and smooth wall surfaces was demonstrated. Fungi of the genera Cladosporium and Emericella with large spores adhered better to smooth surfaces while those of the genus Aspergillus with smaller conidia adhered better to rough surfaces. The application of three incubation temperatures helped provide a fuller picture of the mycobiota in the school environment.

  15. Simplified design procedure for base isolation system

    Energy Technology Data Exchange (ETDEWEB)

    Takayama, Mineo; Tada, Hideyuki [Fukuoka Univ. (Japan). Faculty of Engineering

    1995-12-01

    This paper presents a simplified design procedure which incorporates an existing response prediction method for base isolated buildings into design methods for isolation devices (rubber bearings and hysteresis dampers). The procedure enables a designer to easily identify the relationship between tile seismic behavior of base-isolated buildings and the characteristics of isolation devices. The prediction method, proposed by Prof. Akiyama, is based on energy balance between the total input seismic energy and the energy absorbed by the isolation devices. The method is very accurate. The design methods for devices were developed by authors based on experimental and finite element analysis results.

  16. Thermodynamic laws in isolated systems.

    Science.gov (United States)

    Hilbert, Stefan; Hänggi, Peter; Dunkel, Jörn

    2014-12-01

    The recent experimental realization of exotic matter states in isolated quantum systems and the ensuing controversy about the existence of negative absolute temperatures demand a careful analysis of the conceptual foundations underlying microcanonical thermostatistics. Here we provide a detailed comparison of the most commonly considered microcanonical entropy definitions, focusing specifically on whether they satisfy or violate the zeroth, first, and second laws of thermodynamics. Our analysis shows that, for a broad class of systems that includes all standard classical Hamiltonian systems, only the Gibbs volume entropy fulfills all three laws simultaneously. To avoid ambiguities, the discussion is restricted to exact results and analytically tractable examples. PMID:25615053

  17. [Neuroanatomy of Isolated Body Lateropulsion].

    Science.gov (United States)

    Nakazato, Yoshihiko; Tamura, Naotoshi; Ikeda, Kei; Tanaka, Ai; Yamamoto, Toshimasa

    2016-03-01

    Axial body lateropulsion, a phenomenon where the body is pulled toward the side of the lesion, with tendency of falling down, is the well-known transient feature of lateral medullary syndrome. In some cases, axial body lateropulsion occurs without vestibular and cerebellar symptoms (isolated body lateropulsion:[iBL]). Patients with iBL have a lesion located in the spinocerebellar tract, descending lateral vestibulospinal tract, vestibulo-thalamic pathway, dentatorubrothalamic pathway, or thalamocortical fascicle. This review deals with the anatomic basis and clinical significance of iBL. PMID:27001775

  18. Investigation of mercury thruster isolators. [service life

    Science.gov (United States)

    Mantenieks, M. A.

    1973-01-01

    Mercury ion thruster isolator lifetime tests were performed using different isolator materials and geometries. Tests were performed with and without the flow of mercury through the isolators in an oil diffusion pumped vacuum facility and cryogenically pumped bell jar. The onset of leakage current in isolators tested occurred in time intervals ranging from a few hours to many hundreds of hours. In all cases, surface contamination was responsible for the onset of leakage current and subsequent isolator failure. Rate of increase of leakage current and the leakage current level increased approximately exponentially with isolator temperature. Careful attention to shielding techniques and the elimination of sources of metal oxides appear to have eliminated isolator failures as a thruster life limiting mechanism.

  19. Blackbody Radiation from Isolated Neptunes

    CERN Document Server

    Ginzburg, Sivan; Loeb, Abraham

    2016-01-01

    Recent analyses of the orbits of some Kuiper Belt objects hypothesize the presence of an undiscovered Neptune-size planet at a very large separation from the Sun. The energy budget of Neptunes on such distant orbits is dominated by the internal heat released by their cooling rather than solar irradiation (making them effectively "isolated"). The blackbody radiation that these planets emit as they cool may provide the means for their detection. Here we use an analytical toy model to study the cooling and radiation of isolated Neptunes. This model can translate a detection (or a null detection) to a constraint on the size and composition of the hypothesized "Planet Nine". Specifically, the thick gas atmosphere of Neptune-like planets serves as an insulating blanket which slows down their cooling. Therefore, a measurement of the blackbody temperature, $T_{\\rm eff}\\sim 50\\textrm{K}$, at which a Neptune emits can be used to estimate the mass of its atmosphere, $M_{\\rm atm}$. Explicitly, we find the relation $T_{\\r...

  20. Nuclear Activity In Isolated Galaxies

    CERN Document Server

    Hernandez-Ibarra, Francisco; Krongold, Yair; Del Olmo, Ascencion; Perea, Jaime; Gonzalez, Jesus

    2012-01-01

    We present a spectroscopic study of the incidence of AGN nuclear activity in two samples of isolated galaxies (Karachentseva, V.E. & Varela, J.). Our results show that the incidence of non-thermal nuclear activity is about 43% and 31% for galaxies with emission lines and for the total sample 40% and 27% respectively. For the first time we have a large number of bona-fide isolated galaxies (513 objects), with statistically significant number of all types. We find a clear relation between bulge mass and the incidence of nuclear activity in the sample with emission lines. This relation becomes flatter when we take into account the complete sample with no emission line galaxies. A large fration ($\\sim$70%) of elliptical galaxies or early type spirals have an active galactic nucleus and $\\sim$70% of them are LINERs. Only 3% of the AGN show the presence of broad lines (a not a single one can be classified as type 1 AGN). This is a remarkable result which is completely at odds with the unified model even if we c...

  1. Isolation of technogenic magnetic particles

    International Nuclear Information System (INIS)

    Technogenic magnetic particles (TMPs) emitted by various industrial sources, such as smelting plants, end up after atmospheric transfer on the soil surface. In the present study, we characterised the origin and composition of such particles emitted by a large iron smelting plant and deposited on particular substrates, namely tombstones, which act as a very interesting and appropriate matrix when compared to soil, tree bark, lichens or attic dust. The isolation and subsequent description of TMPs require a critical step of separation between different components of the sample and the magnetic particles; here, we described an efficient protocol that fulfils such a requirement: it resorts to water suspension, sonication, repeated magnetic extraction, sedimentation, sieving and organic matter destruction at 550 °C in some instances. The isolated TMPs displayed a noticeable crystalline shape with variable compositions: a) pure iron oxides, b) iron + Cr, Ni or Zn, and c) a complex structure containing Ca, Si, Mg, and Mn. Using Scanning Electron Microscope Energy Dispersive X-ray (SEM–EDX), we obtained profiles of various and distinct magnetic particles, which allowed us to identify the source of the TMPs. - Highlights: • The developed method offers a low-cost approach of large-scale dry deposition. • Tombstones are excellent supports for sampling these atmospheric deposits. • Smelted elements crystallise after cooling, giving typical technogenic magnetic particles (TMPs). • Coupling microscopic and bulk analyses allows identifying TMP origin. • Magnetic TMPs issued from steel industry were separated by a new technique

  2. Isolation of technogenic magnetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Catinon, Mickaël, E-mail: mickael.catinon@gmail.com [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France); Ayrault, Sophie, E-mail: sophie.ayrault@lsce.ispl.fr [Laboratoire des Sciences du Climat et de l' Environnement, UMR 8212, CEA-CNRS-UVSQ/IPSL, 91198 Gif-sur-Yvette (France); Boudouma, Omar, E-mail: boudouma@ccr.jussieu.fr [Service du MEB, UFR928, Université Pierre et Marie Curie, 75252 Paris VI (France); Bordier, Louise, E-mail: Louise.Bordier@lsce.ipsl.fr [Laboratoire des Sciences du Climat et de l' Environnement, UMR 8212, CEA-CNRS-UVSQ/IPSL, 91198 Gif-sur-Yvette (France); Agnello, Gregory, E-mail: contact@evinrude.fr [Evinrude, Espace St Germain, 38200 Vienne (France); Reynaud, Stéphane, E-mail: stephane.reynaud@ujf-grenoble.fr [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France); Tissut, Michel, E-mail: michel.tissut@ujf-grenoble.fr [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France)

    2014-03-01

    Technogenic magnetic particles (TMPs) emitted by various industrial sources, such as smelting plants, end up after atmospheric transfer on the soil surface. In the present study, we characterised the origin and composition of such particles emitted by a large iron smelting plant and deposited on particular substrates, namely tombstones, which act as a very interesting and appropriate matrix when compared to soil, tree bark, lichens or attic dust. The isolation and subsequent description of TMPs require a critical step of separation between different components of the sample and the magnetic particles; here, we described an efficient protocol that fulfils such a requirement: it resorts to water suspension, sonication, repeated magnetic extraction, sedimentation, sieving and organic matter destruction at 550 °C in some instances. The isolated TMPs displayed a noticeable crystalline shape with variable compositions: a) pure iron oxides, b) iron + Cr, Ni or Zn, and c) a complex structure containing Ca, Si, Mg, and Mn. Using Scanning Electron Microscope Energy Dispersive X-ray (SEM–EDX), we obtained profiles of various and distinct magnetic particles, which allowed us to identify the source of the TMPs. - Highlights: • The developed method offers a low-cost approach of large-scale dry deposition. • Tombstones are excellent supports for sampling these atmospheric deposits. • Smelted elements crystallise after cooling, giving typical technogenic magnetic particles (TMPs). • Coupling microscopic and bulk analyses allows identifying TMP origin. • Magnetic TMPs issued from steel industry were separated by a new technique.

  3. Braking Index of Isolated Pulsars

    CERN Document Server

    Hamil, Oliver Q; Urbanec, Martin; Urbancova, Gabriela

    2016-01-01

    Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\\Omega$, and their time derivatives that show unambiguously that the pulsars are slowing down. The commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of $\\Omega$. This relation leads to the power law $\\dot{\\Omega}$ = -K $\\Omega^{\\rm n}$ where $n$ is called the braking index. The MDR model predicts $n$ exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of $n$, individually accurate to a few percent or better, in the range 1$ <$ n $ < $ 2.8, which is consistently less than the predictions of the MDR model. In spite of an extensive investigation of various modifications of the MDR model, no satisfactory explanation of observation has been found yet. The aim of this work is t...

  4. Isolation of technogenic magnetic particles.

    Science.gov (United States)

    Catinon, Mickaël; Ayrault, Sophie; Boudouma, Omar; Bordier, Louise; Agnello, Gregory; Reynaud, Stéphane; Tissut, Michel

    2014-03-15

    Technogenic magnetic particles (TMPs) emitted by various industrial sources, such as smelting plants, end up after atmospheric transfer on the soil surface. In the present study, we characterised the origin and composition of such particles emitted by a large iron smelting plant and deposited on particular substrates, namely tombstones, which act as a very interesting and appropriate matrix when compared to soil, tree bark, lichens or attic dust. The isolation and subsequent description of TMPs require a critical step of separation between different components of the sample and the magnetic particles; here, we described an efficient protocol that fulfils such a requirement: it resorts to water suspension, sonication, repeated magnetic extraction, sedimentation, sieving and organic matter destruction at 550 °C in some instances. The isolated TMPs displayed a noticeable crystalline shape with variable compositions: a) pure iron oxides, b) iron+Cr, Ni or Zn, and c) a complex structure containing Ca, Si, Mg, and Mn. Using Scanning Electron Microscope Energy Dispersive X-ray (SEM-EDX), we obtained profiles of various and distinct magnetic particles, which allowed us to identify the source of the TMPs. PMID:24419285

  5. From rumors to genetic isolates

    Directory of Open Access Journals (Sweden)

    Eduardo E. Castilla

    2014-01-01

    Full Text Available Here we propose a registration process for population genetic isolates, usually geographic clusters of genetic disorders, based on the systematic search of rumors, defined as any type of account regardless of its reliability. Systematically ascertained rumors are recorded, and validated through a progressive process of pre-established steps. This paper outlines the conceptual basis for this approach and presents the preliminary results from a rumor-based nationwide registry of genetically isolated populations, named CENISO (Censo Nacional de Isolados, operating in Brazil since 2009. During the first four years of its existence (2009-2013, a total of 191 Rumors were registered and validated, resulting in a prevalence rate of one per million inhabitants of Brazil. When the five statutory geographic regions of Brazil were considered, more Rumors were registered for the Northeast (2.11; 1.74-2.54 per 10(6 than for the remaining four regions, North, Center-West, Southeast, and South, which did not differ among themselves. About half (86/191 of the recorded rumors were proven to be geographic clusters; of these disorders, 58 were autosomal recessive, 17 autosomal dominant, 5 X-linked, 3 multifactorial, and one environmental (thalidomide embryopathy.

  6. Characterization of Sclerotinia sclerotiorum Isolated from Paprika.

    Science.gov (United States)

    Jeon, Young-Jae; Kwon, Hyuk-Woo; Nam, Ji-Sun; Kim, Seong Hwan

    2006-09-01

    A fungal isolate collected from infected paprika (Capsicum annuum var. grossum) was characterized as Sclerotinia sclerotiorum based on its ability of sclerotium formation, physiological and molecular properties. When the isolate was grown on potato dextrose agar, oatmeal agar, and malt extract agar, it grew most well on PDA. Optimal temperature and pH for its growth were 25℃ and pH 7, respectively. The fungal isolate produced sclerotia on PDA within 10 days, and the color and shape of the sclerotia were similar to those of S. sclerotiorum . The ITS rDNA regions including ITS1 and ITS2 and 5.8S sequences were amplified using ITS1F and ITS4 primers from the genomic DNAs of the paprika isolate and other known pathogenic S. sclerotiorum isolated from different crops in Korea, and their nucleotide sequences were determined. Sequence comparison analysis showed the ITS rDNA of the paprika isolate shares 100% sequence identity with those of S. sclerotiorum isolated from red pepper, lettuce and a S. sclerotiorum isolate registered in GenBank DNA database. Neighbor joining analysis based on the ITS rDNA sequence revealed the paprika isolate has very close phylogenetic relationships with known Sclerotinia sclerotiorum isolates. This is the first report that S. sclerotiorum has been found associated with paprika rot in paprika growing countries. PMID:24039491

  7. Effectiveness of Base Isolation Technique and Influence of Isolator Characteristics on Response of a Base Isolated Building

    OpenAIRE

    Sunita Tolani; Dr. Ajay Sharma

    2016-01-01

    This study concerns with the seismic response comparison of a fixed base building with a base isolated building and parametric study of a base isolated building. The structural system considered for analysis is a three storey reinforced concrete building, which is idealized as a shear type building with one lateral degree of freedom at each floor level. The isolation systems considered for this study are Laminated Rubber bearing (LRB), Lead Rubber Bearing (N-Z bearing) and Frictio...

  8. Spectroscopy of Isolated Prebiotic Nucleobases

    Science.gov (United States)

    Svadlenak, Nathan; Callahan, Michael P.; Ligare, Marshall; Gulian, Lisa; Gengeliczki, Zsolt; Nachtigallova, Dana; Hobza, Pavel; deVries, Mattanjah

    2011-01-01

    We use multiphoton ionization and double resonance spectroscopy to study the excited state dynamics of biologically relevant molecules as well as prebiotic nucleobases, isolated in the gas phase. Molecules that are biologically relevant to life today tend to exhibit short excited state lifetimes compared to similar but non-biologically relevant analogs. The mechanism is internal conversion, which may help protect the biologically active molecules from UV damage. This process is governed by conical intersections that depend very strongly on molecular structure. Therefore we have studied purines and pyrimidines with systematic variations of structure, including substitutions, tautomeric forms, and cluster structures that represent different base pair binding motifs. These structural variations also include possible alternate base pairs that may shed light on prebiotic chemistry. With this in mind we have begun to probe the ultrafast dynamics of molecules that exhibit very short excited states and search for evidence of internal conversions.

  9. Braking index of isolated pulsars

    Science.gov (United States)

    Hamil, O.; Stone, J. R.; Urbanec, M.; Urbancová, G.

    2015-03-01

    Isolated pulsars are rotating neutron stars with accurately measured angular velocities Ω , and their time derivatives that show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of detailed debate, the commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. Other processes, including the emission of gravitational radiation, and of relativistic particles (pulsar wind), are also being considered. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of Ω . This relation leads to the power law Ω ˙ =-K Ωn where n is called the braking index. The MDR model predicts n exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of n , individually accurate to a few percent or better, in the range 1

  10. Osteocyte isolation and culture methods.

    Science.gov (United States)

    Shah, Karan M; Stern, Matt M; Stern, Amber R; Pathak, Janak L; Bravenboer, Nathalie; Bakker, Astrid D

    2016-01-01

    The aim of this paper is to present several popular methods for in vitro culture of osteocytes and osteocyte cell lines. Osteocytes are located extremely suitably within the calcified bone matrix to sense mechanical signals, and are equipped with a multitude of molecular features that allow mechanosensing. However, osteocytes are more than specialized mechanosensing cells. Several signaling molecules are preferentially produced by osteocytes, and osteocytes hold a tight reign over osteoblast and osteoclast formation and activity, but also have a role as endocrine cell, communicating with muscles or organs as remote as the kidneys. In order to facilitate further research into this fascinating cell type, three protocols will be provided in this paper. The first protocol will be on the culture of mouse (early) osteocyte cell lines, the second on the isolation and culture of primary mouse bone cells, and the third on the culture of fully embedded human osteocytes within their own three-dimensional bone matrix. PMID:27648260

  11. Bacterial isolates degrading aliphatic polycarbonates.

    Science.gov (United States)

    Suyama, T; Hosoya, H; Tokiwa, Y

    1998-04-15

    Bacteria that degrade an aliphatic polycarbonate, poly(hexamethylene carbonate), were isolated from river water in Ibaraki. Prefecture, Japan, after enrichment in liquid medium containing poly(hexamethylene carbonate) suspensions as carbon source, and dilution to single cells. Four of the strains, 35L, WFF52, 61A and 61B2, degraded poly(hexamethylene carbonate) on agar plate containing suspended poly(hexamethylene carbonate). Degradation of poly(hexamethylene carbonate) was confirmed by gel permeation chromatography. Besides poly(hexamethylene carbonate), the strains were found to degrade poly(tetramethylene carbonate). The strains were characterized morphologically, physiologically, and by 16S rDNA sequence analysis. Strains 35L and WFF52 were tentatively identified as Pseudomonas sp. and Variovorax sp., respectively, while strains 61A and 61B2 constitute an unidentified branch within the beta subclass of the Proteobacteria.

  12. Propellant isolation shutoff valve program

    Science.gov (United States)

    Merritt, F. L.

    1973-01-01

    An analysis and design effort directed to advancing the state-of-the-art of space storable isolation valves for control of flow of the propellants liquid fluorine/hydrazine and Flox/monomethylhydrazine is discussed. Emphasis is on achieving zero liquid leakage and capability of withstanding missions up to 10 years in interplanetary space. Included is a study of all-metal poppet sealing theory, an evaluation of candidate seal configurations, a valve actuator trade-off study and design description of a pneumo-thermally actuated soft metal poppet seal valve. The concepts and analysis leading to the soft seal approach are documented. A theoretical evaluation of seal leakage versus seal loading, related finishes and yield strengths of various materials is provided. Application of a confined soft aluminum seal loaded to 2 to 3 times yield strength is recommended. Use of either an electro-mechanical or pneumatic actuator appears to be feasible for the application.

  13. Multiple isolated cutaneous plexiform schwannomas

    Directory of Open Access Journals (Sweden)

    Enas A. S. Attia

    2011-01-01

    Full Text Available Plexiform schwannoma is a rare neurogenic tumor, arising from skin and subcutaneous tissue. The presence of multiple schwannomas suggests a possible association with neurofibromatosis type 2 (NF2. A 50-year old male patient presented with multiple papulo-nodular cutaneous lesions on both arms and forearms. Histopathological examination revealed a dermal multinodular pattern of well-circumscribed masses of closely packed cells, with peripheral myxoid tissue, well-encapsulated in a thin collagenous capsule. S-100 immunohistochemical staining was diffusely and strongly positive. Neuron-specific enolase was positive, confirming a neural tissue tumor. An audiogram and Magnetic Resonance Imaging (MRI of cerebro-pontine angle showed no detected abnormality, excluding acoustic neuroma. Thus, we present a case of multiple bilateral isolated cutaneous plexiform schwannomas, not associated with NF2. Multiple plexiform schwannomas is a very rare entity, distinct from neurofibromatosis (NF, and being confined to the dermis is even more rarely reported.

  14. An isolated nasolacrimal duct osteoma.

    Science.gov (United States)

    Kim, Joo Yeon; Kwon, Jae Hwan

    2013-07-01

    Osteomas of the nose and paranasal sinus are common benign tumors that can extend to surrounding structures and result in orbital or intracranial involvement. Presenting symptoms include facial pain, headache, cerebral symptoms, ocular symptoms, and so on, depending on the location and size of the tumor. They commonly occur within the frontal, ethmoid, maxillary, and sphenoid sinuses; however, there are rare cases of reported osteomas in the nasal cavity, turbinate, or orbit. Our case report describes a patient with nasolacrimal duct osteoma who presented with ipsilateral ocular pain, epiphora, and medial canthal swelling. We performed intranasal dacryocystorhinostomy using a nasal endoscope and removed the lacrimal duct osteoma. This report describes symptoms and management of an isolated nasolacrimal duct stone with a review of the literature.

  15. Genetically distinct Glossina fuscipes fuscipes populations in the Lake Kyoga region of Uganda and its relevance for human African trypanosomiasis.

    Science.gov (United States)

    Echodu, Richard; Sistrom, Mark; Hyseni, Chaz; Enyaru, John; Okedi, Loyce; Aksoy, Serap; Caccone, Adalgisa

    2013-01-01

    Tsetse flies (Glossina spp.) are the sole vectors of Trypanosoma brucei--the agent of human (HAT) and animal (AAT) trypanosomiasis. Glossina fuscipes fuscipes (Gff) is the main vector species in Uganda--the only country where the two forms of HAT disease (rhodesiense and gambiense) occur, with gambiense limited to the northwest. Gff populations cluster in three genetically distinct groups in northern, southern, and western Uganda, respectively, with a contact zone present in central Uganda. Understanding the dynamics of this contact zone is epidemiologically important as the merger of the two diseases is a major health concern. We used mitochondrial and microsatellite DNA data from Gff samples in the contact zone to understand its spatial extent and temporal stability. We show that this zone is relatively narrow, extending through central Uganda along major rivers with south to north introgression but displaying no sex-biased dispersal. Lack of obvious vicariant barriers suggests that either environmental conditions or reciprocal competitive exclusion could explain the patterns of genetic differentiation observed. Lack of admixture between northern and southern populations may prevent the sympatry of the two forms of HAT disease, although continued control efforts are needed to prevent the recolonization of tsetse-free regions by neighboring populations.

  16. Isolation and Identification of Concrete Environment Bacteria

    Science.gov (United States)

    Irwan, J. M.; Anneza, L. H.; Othman, N.; Husnul, T.; Alshalif, A. F.

    2016-07-01

    This paper presents the isolation and molecular method for bacteria identification through PCR and DNA sequencing. Identification of the bacteria species is required in order to fully utilize the bacterium capability for precipitation of calcium carbonate in concrete. This process is to enable the addition of suitable catalyst according to the bacterium enzymatic pathway that is known through the bacteria species used. The objective of this study is to isolate, enriched and identify the bacteria species. The bacteria in this study was isolated from fresh urine and acid mine drainage water, Kota Tinggi, Johor. Enrichment of the isolated bacteria was conducted to ensure the bacteria survivability in concrete. The identification of bacteria species was done through polymerase chain reaction (PCR) and rRDNA sequencing. The isolation and enrichment of the bacteria was done successfully. Whereas, the results for bacteria identification showed that the isolated bacteria strains are Bacillus sp and Enterococus faecalis.

  17. Hyaluronidase in Clinical Isolates of Propionibacterium acnes

    OpenAIRE

    Harmony Tyner; Robin Patel

    2015-01-01

    Objectives. We sought to describe the prevalence of a hyaluronidase gene and hyaluronidase production in 197 clinical isolates of P. acnes; we assessed kinetics of hyaluronidase production in a subset of three isolates. Methods. The hyaluronidase gene was detected using polymerase chain reaction. Hyaluronidase production was detected by growing isolates on BHI agar containing 400 μg/mL hyaluronic acid and 1% albumin and flooding plates with 2 N glacial acetic acid to precipitate unbound hyalu...

  18. Isolation of Helicobacter pylori from saliva.

    OpenAIRE

    Ferguson, D A; C. Li; Patel, N. R.; Mayberry, W R; Chi, D S; Thomas, E.

    1993-01-01

    Helicobacter pylori was grown in low numbers from the saliva of one of nine patients who were positive for gastric H. pylori. The saliva-derived isolate from this patient was identical to the antral biopsy-derived isolate from the same patient and differed from isolates cultured from the antral biopsies of all other patients by soluble-protein electrophoresis, restriction endonuclease DNA analysis, and Southern blot hybridization. This is the first observation, to our knowledge, of the recove...

  19. Molecular identification of Korean Trichinella isolates

    OpenAIRE

    Sohn, Woon-Mok; Huh, Sun; Chung, Dong-Il; Pozio, Edoardo

    2003-01-01

    Muscle larvae of Trichinella isolates from two outbreaks in Korea were analyzed by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and multiple-PCR. All of the muscle larvae showed a band similar to that of T. spiralis larvae of the reference strain. The two Korean Trichinella isolates (isolate code ISS623 and ISS1078) might be classifiable to Trichinella spiralis.

  20. Isolated trochlear nerve palsy with midbrain hemorrhage

    Directory of Open Access Journals (Sweden)

    Raghavendra S

    2010-01-01

    Full Text Available Midbrain hemorrhage causing isolated fourth nerve palsy is extremely rare. Idiopathic, traumatic and congenital abnormalities are the most common causes of fourth nerve palsy. We report acute isolated fourth nerve palsy in an 18-year-old lady due to a midbrain hemorrhage probably due to a midbrain cavernoma. The case highlights the need for neuroimaging in selected cases of isolated trochlear nerve palsy.

  1. Isolated systems with wind power. Main report

    DEFF Research Database (Denmark)

    Lundsager, P.; Bindner, Henrik W.; Clausen, Niels-Erik;

    2001-01-01

    approach for assessing the technical and economical feasibility of isolated power supply systems with wind energy. As a part of the project the following tasks were carried out: Review of literature, fieldmeasurements in Egypt, development of an inventory of small isolated systems, overview of end......The overall objective of this research project is to study the development of methods and guidelines rather than "universal solutions" for the use of wind energy in isolated communities. The main specific objective of the project is to develop and present amore unified and generally applicable...... for Isolated Systems with Wind Power, applicable for international organisations such as donoragencies and development banks....

  2. Variable stiffness and damping magnetorheological isolator

    Institute of Scientific and Technical Information of China (English)

    Yang ZHOU; Xingyu WANG; Xianzhou ZHANG; Weihua LI

    2009-01-01

    This paper presents the development and characterization of a magnetorheological (MR) fluid-based variable stiffness and damping isolator. The prototype of the MR fluid isolator is fabricated, and its dynamic behavior is measured under various applied magnetic fields. The parameters of the model under various magnetic fields are identified, and the dynamic perfor-mance of the isolator is evaluated in simulation. Experi-mental results indicate that both the stiffness and damping capability of the developed MR isolator can be controlled by an external magnetic field.

  3. The Dynamic Characteristics of Silicone Rubber Isolator

    Institute of Scientific and Technical Information of China (English)

    YU Lianjiang; LIU Suling; YE Linming; HUANG Guangsu; XU Yuntao

    2012-01-01

    The dynamic stiffness and the specific damping energy,as well as the vibration response characteristics of a silicone rubber isolator were researched.The results of the vibration test showed that the silicone rubber isolator was excellent in the performance of vibration control.The dynamic stiffness and the damping characteristics were non-linear.From the comparison between experimental results and simulation analysis,the displacement transmissibility characteristics of the isolator were obtained.As a result,the dynamic characteristics of the isolator could be accurately described by the quadratic type non-linear terms at small amplitude.

  4. Permanent isolation surface barrier: Functional performance

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.

    1993-10-01

    This document presents the functional performance parameters for permanent isolation surface barriers. Permanent isolation surface barriers have been proposed for use at the Hanford Site (and elsewhere) to isolate and dispose of certain types of waste in place. Much of the waste that would be disposed of using in-place isolation techniques is located in subsurface structures, such as solid waste burial grounds, tanks, vaults, and cribs. Unless protected in some way, the wastes could be transported to the accessible environment via transport pathways, such as water infiltration, biointrusion, wind and water erosion, human interference, and/or gaseous release.

  5. Isolation Studies for Di-photon Searches

    CERN Document Server

    Mak, Sze Ning

    2015-01-01

    The run2 LHC will focus on searching for new particles, such as, additional Higgs particles, gravitons etc. If those particles can decay to diphoton (either at tree level or via loop), that will be the most promising channel since it provides clean signature. In order to provide the final results in a fiducial region, truth isolation equivalent to the reconstructed isolation cut need to be applied. In this study, we found that the same reco isolation cuts correspond to looser truth isolation cuts for higher invariant masses.

  6. Study on ultimate behavior of base-isolated building: Effect of random rupture of isolation device

    International Nuclear Information System (INIS)

    This paper describes the results of the numerical analysis on the ultimate behavior of the base-isolated Fast Breeder Reactor (FBR) building with 272 isolation devices from the viewpoint of the Cascade Failure phenomenon so that the rupture of an arbitrary isolator might induce that of others. Three-dimensional seismic response analyses are carried out, in which the rupture of isolators are considered, and the influence on the ultimate behavior of the isolation layer due to the torsional response which is attributable to partial rupture of isolators is investigated. Further, fragility of the seismic isolation layer is evaluated by employing the Monte Carlo Simulation technique, where randomness of strength of the isolation device is considered

  7. Teaching basic lung isolation skills on human anatomy simulator: attainment and retention of lung isolation skills

    OpenAIRE

    Latif, Rana K.; VanHorne, Edgar M.; Kandadai, Sunitha Kanchi; Bautista, Alexander F.; Neamtu, Aurel; Wadhwa, Anupama; Carter, Mary B.; Ziegler, Craig H.; Memon, Mohammed Faisal; Akça, Ozan

    2016-01-01

    Background Lung isolation skills, such as correct insertion of double lumen endobronchial tube and bronchial blocker, are essential in anesthesia training; however, how to teach novices these skills is underexplored. Our aims were to determine (1) if novices can be trained to a basic proficiency level of lung isolation skills, (2) whether video-didactic and simulation-based trainings are comparable in teaching lung isolation basic skills, and (3) whether novice learners’ lung isolation skills...

  8. Understanding the differences in gelling properties between lupin protein isolate and soy protein isolate

    NARCIS (Netherlands)

    Berghout, J.A.M.; Boom, R.M.; Goot, van der A.J.

    2015-01-01

    The gelling properties of lupin protein isolate (LPI) were compared with those of soy protein isolate (SPI). It was found that LPI behaves fundamentally different than SPI, evidenced by the formation of weaker and deformable gels. Further investigation shows that both protein isolates can be conside

  9. Scalable Detection and Isolation of Phishing

    NARCIS (Netherlands)

    Moreira Moura, G.C.; Pras, A.

    2009-01-01

    This paper presents a proposal for scalable detection and isolation of phishing. The main ideas are to move the protection from end users towards the network provider and to employ the novel bad neighborhood concept, in order to detect and isolate both phishing e-mail senders and phishing web server

  10. Gene Diversity of Trichomonas Vaginalis Isolates

    Directory of Open Access Journals (Sweden)

    Z Valadkhani

    2011-09-01

    Full Text Available Background: Trichomonas vaginalis is protozoan parasite responsible for trichomoniasis and is more common in high-risk behavior group such as prostitute individuals. Interest in trichomoni­asis is due to increase one's susceptibility to viruses such as herpes, human papillomavirus and HIV. The aim of this study was to find genotypic differences between the isolates.Methods: Forty isolates from prisoners' women in Tehran province were used in this study. The random amplified polymorphic DNA (RAPD technique was used to determine genetic differ­ences among isolates and was correlated with patient's records. By each primer the banding pat­tern size of each isolates was scored (bp, genetic differences were studied, and the genealogical tree was constructed by using NTSYS software program and UPGMA method.Results: The least number of bands were seen by using primer OPD8 and the most by using OPD3. Results showed no significant difference in isolates from different geographical areas in Iran. By using primer OPD1 specific amplified fragment with length 1300 base pair were found in only 8 isolates. All these isolates were belonged to addicted women; however, six belonged to asymptomatic patients and two to symptomatic ones.Conclusion: There was not much genetic diversity in T vaginalis isolates from three different geo­graphical areas.

  11. Decode Fish Lymphocystis Virus Isolated from China

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Aresearch group headed by Prof. Zhang Qiya from the CAS Institute of Hydrobiology (IHB) has succeeded in sequencing the complete genome of lymphocystis disease virus isolated from China (LCDV-C), a virus isolated from cultured flounder (Paralichthys olivaceus) with lymphocystis disease in China. Their work has been published in the recent issue of Journal of Virology (2004, 78 (13): 6982- 6994).

  12. Vibration Isolation Review: II. Shock Excitation

    OpenAIRE

    F.C. Nelson

    1996-01-01

    This is the second part of a two part review of shock and vibration isolation. It covers three distinct categories of shock excitation—pulselike shock, velocity shock, and complex shock—and discusses the means that are available in each case to measure the effectiveness of shock mitigation by the imposition of flexible connections between the isolated system and its base.

  13. Isolation of glycoproteins from brown algae.

    OpenAIRE

    Surendraraj, Alagarsamy; Farvin Koduvayur Habeebullah , Sabeena; Jacobsen, Charlotte

    2015-01-01

    The present invention relates to a novel process for the isolation of unique anti-oxidative glycoproteins from the pH precipitated fractions of enzymatic extracts of brown algae. Two brown seaweeds viz, Fucus serratus and Fucus vesiculosus were hydrolysed by using 3 enzymes viz, Alcalase, Viscozyme and Termamyl and the glycoproteins were isolated from these enzyme extracts.

  14. Fault Isolation for Shipboard Decision Support

    DEFF Research Database (Denmark)

    Lajic, Zoran; Blanke, Mogens; Nielsen, Ulrik Dam

    2010-01-01

    Fault detection and fault isolation for in-service decision support systems for marine surface vehicles will be presented in this paper. The stochastic wave elevation and the associated ship responses are modeled in the frequency domain. The paper takes as an example fault isolation of a containe...

  15. Epidemic model with isolation in multilayer networks

    CERN Document Server

    Zuzek, L G Alvarez; Braunstein, L A

    2014-01-01

    The Susceptible-Infected-Recovered (SIR) model has successfully mimicked the propagation of such airborne diseases as influenza A (H1N1). Although the SIR model has recently been studied in a multilayer networks configuration, in almost all the research the dynamic movement of infected individuals, e.g., how they are often kept in isolation, is disregarded. We study the SIR model in two multilayer networks and use an isolation parameter, indicating time period, to measure the effect of isolating infected individuals from both layers. This isolation reduces the transmission of the disease because the time in which infection can spread is reduced. In this scenario we find that the epidemic threshold increases with the isolation time and the isolation parameter and the impact of the propagation is reduced. We also find that when isolation is total there is a threshold for the isolation parameter above which the disease never becomes an epidemic. We also find that regular epidemic models always overestimate the e...

  16. Fusarium Species Isolated from Forest Soil Samples

    OpenAIRE

    Azaman, R. S.; Latiffah, Z.

    2011-01-01

    A total of 46 isolates of Fusarium were isolated from six forest soil samples in Muka Head, Teluk Bahang, Pulau Pinang. Two Fusarium species were identified from the soil samples namely, F. solani (93.5%) and F. oxysporum (6.5%). The present study showed that the diversity and occurrences of Fusarium species in forest soil was low compared to cultivated soils.

  17. Seismic isolation: Which way to go?

    Energy Technology Data Exchange (ETDEWEB)

    Shustov, V. [Seismic Risk Evaluation Co., Los Angeles, CA (United States)

    1995-12-01

    There are known limitations in current seismic isolation designs which, particularly, use shearing type (e.g. rubber) bearings as isolators. This paper identifies some of the limitations and describes an alternative design. The technical basis and advantages of the new approach are presented.

  18. K-Basin isolation barrier seal

    International Nuclear Information System (INIS)

    This report documents various aspects of the design, analysis, procurement, and fabrication of the hydraulic seal on the isolation barriers to be installed in the 100-K Area spent nuclear fuel basin. The isolation barrier is used to keep water in the basin in the event of an earthquake

  19. TRYPANOCIDAL ACTIVE COMPOUNDS FROM SCOTTISH ABIES NOBILIS AND PINUS SYLVESTRIS

    Directory of Open Access Journals (Sweden)

    Veronique Seidel

    2013-02-01

    Full Text Available Three active compounds obtained from the aerial parts of Abies nobilis and Pinus sylvestris isolated by different chromatographic techniques. Their structures were identified by NMR (1H, 13C, COSY, HMBC spectroscopic and mass spectrometric data and established as catechin, dehydroabietic acid and Dihydroconiferyl alcohol. The isolated compounds were exhibited activity against blood stream form of parasite Trypanosoma brucei brucei (S 427.

  20. Isolation of Pasteurella multocida from broiler chickens

    Directory of Open Access Journals (Sweden)

    Sri Poernomo

    1996-06-01

    Full Text Available Pasteurella multocida, the etiological agent of fowl cholera, was isolated from five, 32 days oldbroilerchickens in the late of 1992. The chickens were from a farm located in Bogor area, raised in cages and each flock consisted of 1,550 broilers . Therewere 230 birds, aging from 28-31 days old, died with clinical signs of lameness and difficulty in breathing. Serological test of the isolate revealed serotype Aof Carter classification . To prove its virulences, the isolate was then inoculated into 3 mice subcutaneously. The mice died less then 24 hours postinoculation and P. multocida can be reisolated . The sensitivity test to antibiotics and sulfa preparations showed that the isolate was sensitive to ampicillin, doxycyclin, erythromycin, gentamycin, sulfamethoxazol-trimethoprim and baytril, but resistance to tetracyclin, kanamycin and oxytetracyclin. This is the first report of P. multocida isolation in broiler chickens in Indonesia, and it is intended to add information on bacterial diseases in poultry in Indonesia.

  1. Sexually dimorphic neuronal responses to social isolation

    Science.gov (United States)

    Senst, Laura; Baimoukhametova, Dinara; Sterley, Toni-Lee; Bains, Jaideep Singh

    2016-01-01

    Many species use social networks to buffer the effects of stress. The mere absence of a social network, however, may also be stressful. We examined neuroendocrine, PVN CRH neurons and report that social isolation alters the intrinsic properties of these cells in sexually dimorphic fashion. Specifically, isolating preadolescent female mice from littermates for neurons. These changes were not evident in age-matched males. By contrast, subjecting either males (isolated or grouped) or group housed females to acute physical stress (swim), increased FSL. The increase in FSL following either social isolation or acute physical stress was blocked by the glucocorticoid synthesis inhibitor, metyrapone and mimicked by exogenous corticosterone. The increase in FSL results in a decrease in the excitability of CRH neurons. Our observations demonstrate that social isolation, but not acute physical stress has sex-specific effects on PVN CRH neurons. DOI: http://dx.doi.org/10.7554/eLife.18726.001 PMID:27725087

  2. Advanced Technology for Isolating Payloads in Microgravity

    Science.gov (United States)

    Alhorn, Dean C.

    1997-01-01

    One presumption of scientific microgravity research is that while in space disturbances are minimized and experiments can be conducted in the absence of gravity. The problem with this assumption is that numerous disturbances actually occur in the space environment. Scientists must consider all disturbances when planning microgravity experiments. Although small disturbances, such as a human sneeze, do not cause most researchers on earth much concern, in space, these minuscule disturbances can be detrimental to the success or failure of an experiment. Therefore, a need exists to isolate experiments and provide a quiescent microgravity environment. The objective of microgravity isolation is to quantify all possible disturbances or vibrations and then attenuate the transmission of the disturbance to the experiment. Some well-defined vibration sources are: experiment operations, pumps, fans, antenna movements, ventilation systems and robotic manipulators. In some cases, it is possible to isolate the source using simple vibration dampers, shock absorbers and other isolation devices. The problem with simple isolation systems is that not all vibration frequencies are attenuated, especially frequencies less than 0.1 Hz. Therefore, some disturbances are actually emitted into the environment. Sometimes vibration sources are not well defined, or cannot be controlled. These include thermal "creak," random acoustic vibrations, aerodynamic drag, crew activities, and other similar disturbances. On some "microgravity missions," such as the United States Microgravity Laboratory (USML) and the International Microgravity Laboratory (IML) missions, the goal was to create extended quiescent times and limit crew activity during these times. This might be possible for short periods, but for extended durations it is impossible due to the nature of the space environment. On the International Space Station (ISS), vehicle attitude readjustments are required to keep the vehicle in a minimum

  3. Cardiac alterations in human African trypanosomiasis (T.b. gambiense with respect to the disease stage and antiparasitic treatment.

    Directory of Open Access Journals (Sweden)

    Johannes A Blum

    Full Text Available BACKGROUND: In Human African Trypanosomiasis, neurological symptoms dominate and cardiac involvement has been suggested. Because of increasing resistance to the available drugs for HAT, new compounds are desperately needed. Evaluation of cardiotoxicity is one parameter of drug safety, but without knowledge of the baseline heart involvement in HAT, cardiologic findings and drug-induced alterations will be difficult to interpret. The aims of the study were to assess the frequency and characteristics of electrocardiographic findings in the first stage of HAT, to compare these findings to those of second stage patients and healthy controls and to assess any potential effects of different therapeutic antiparasitic compounds with respect to ECG changes after treatment. METHODS: Four hundred and six patients with first stage HAT were recruited in the Democratic Republic of Congo, Angola and Sudan between 2002 and 2007 in a series of clinical trials comparing the efficacy and safety of the experimental treatment DB289 to the standard first stage treatment, pentamidine. These ECGs were compared to the ECGs of healthy volunteers (n = 61 and to those of second stage HAT patients (n = 56. RESULTS: In first and second stage HAT, a prolonged QTc interval, repolarization changes and low voltage were significantly more frequent than in healthy controls. Treatment in first stage was associated with repolarization changes in both the DB289 and the pentamidine group to a similar extent. The QTc interval did not change during treatment. CONCLUSIONS: Cardiac involvement in HAT, as demonstrated by ECG alterations, appears early in the evolution of the disease. The prolongation of the QTC interval comprises a risk of fatal arrhythmias if new drugs with an additional potential of QTC prolongation will be used. During treatment ECG abnormalities such as repolarization changes consistent with peri-myocarditis occur frequently and appear to be associated with the disease stage, but not with a specific drug.

  4. Listeria fleischmannii sp. nov., isolated from cheese.

    Science.gov (United States)

    Bertsch, David; Rau, Jörg; Eugster, Marcel R; Haug, Martina C; Lawson, Paul A; Lacroix, Christophe; Meile, Leo

    2013-02-01

    A study was performed on three isolates (LU2006-1(T), LU2006-2 and LU2006-3), which were sampled independently from cheese in western Switzerland in 2006, as well as a fourth isolate (A11-3426), which was detected in 2011, using a polyphasic approach. The isolates could all be assigned to the genus Listeria but not to any known species. Phenotypic and chemotaxonomic data were compatible with the genus Listeria and phylogenetic analysis based on 16S rRNA gene sequences confirmed that the closest relationships were with members of this genus. However, DNA-DNA hybridization demonstrated that the isolates did not belong to any currently described species. Cell-wall-binding domains of Listeria monocytogenes bacteriophage endolysins were able to attach to the isolates, confirming their tight relatedness to the genus Listeria. Although PCR targeting the central portion of the flagellin gene flaA was positive, motility was not observed. The four isolates could not be discriminated by Fourier transform infrared spectroscopy or pulsed-field gel electrophoresis. This suggests that they represent a single species, which seems to be adapted to the environment in a cheese-ripening cellar as it was re-isolated from the same type of Swiss cheese after more than 5 years. Conjugation experiments demonstrated that the isolates harbour a transferable resistance to clindamycin. The isolates did not exhibit haemolysis or show any indication of human pathogenicity or virulence. The four isolates are affiliated with the genus Listeria but can be differentiated from all described members of the genus Listeria and therefore they merit being classified as representatives of a novel species, for which we propose the name Listeria fleischmannii sp. nov.; the type strain is LU2006-1(T) ( = DSM 24998(T)  = LMG 26584(T)).

  5. Isolation of nuc mutant isolates of Staphylococcus aureus from bovine clinical mastitis.

    Science.gov (United States)

    Zastempowska, E; Orczykowska-Kotyna, M; Lassa, H

    2014-06-01

    Isolates of Staphylococcus aureus with a mutation in the nuclease (nuc) gene were recovered from cases of bovine mastitis in Poland. Three S. aureus isolates from cows in one herd had a 42 base pair duplication in the nuc gene. These isolates belonged to sequence type 97 (ST97) and clonal complex 97 (CC97). They had a different spa type and multiple-locus variable-number tandem-repeat fingerprinting (MLVF) subtype than a S. aureus isolate without the nuc mutation from the same herd. Isolation of nuc mutant S. aureus strains from cases of bovine mastitis may confound diagnostic PCRs based on detection of the nuc gene.

  6. Behavioural reproductive isolation and speciation in Drosophila

    Indian Academy of Sciences (India)

    Punita Nanda; Bashisth Narayan Singh

    2012-06-01

    The origin of premating reproductive isolation continues to help elucidate the process of speciation and is the central event in the evolution of biological species. Therefore, during the process of species formation the diverging populations must acquire some means of reproductive isolation so that the genes from one gene pool are prevented from dispersing freely into a foreign gene pool. In the genus Drosophila, the phenomenon of behavioural reproductive isolation, which is an important type of premating (prezygotic) reproductive isolating mechanisms, has been extensively studied and interesting data have been documented. In many cases incomplete sexual isolation has been observed and the pattern and degree of isolation within and between the species have often been used to elucidate the phylogenetic relationships. The present review documents an overview of speciation mediated through behavioural incompatibility in different species groups of Drosophila with particular reference to the models proposed on the basis of one-sided ethological isolation to predict the direction of evolution. This study is crucial for understanding the mechanism of speciation through behavioural incompatibility and also for an understanding of speciation genetics in future prospects.

  7. Effects of isolation on various lymphocyte activities

    Energy Technology Data Exchange (ETDEWEB)

    Jessop, J.J.

    1986-01-01

    Prolonged exposure of Sprague Dawley male rats to isolation, water scheduling, or their combination resulted in an enhanced lymphocyte proliferative response to mitogen. Time course studies of effects of isolation on mitogenic response of splenic and/or blood T and B lymphocytes and splenic NK cell activity demonstrated a suppression with short term exposure followed by an enhancement with prolonged exposure. Use of immunoperoxidase staining techniques to identify splenic T or T helper cells revealed that prolonged exposure to isolation had no significant effect on the proportion of these cell populations in the spleen. Examination of the data by Lineweaver-Burke plot and plot of the data as % maximum response showed that prolonged exposure to isolation did not alter the sensitivity of the lymphocytes to mitogen. Involvement of corticosteroids and opioid peptides in mediation of the effects of exposure to isolation on lymphocyte activity was assessed by measurement of plasma corticosterone by radioimmunoassay and by examination of the ability of the opioid antagonist naltrexone to alter the effects of isolation on lymphocyte proliferative response to mitogen. Attempts were made to mimic the effects of short-term isolation on lymphocyte activity by morphine sulfate administration.

  8. Application of seismic isolation to industrial tanks

    Energy Technology Data Exchange (ETDEWEB)

    Zayas, V.A.; Low, S.S. [Earthquake Protection Systems, San Francisco, CA (United States)

    1995-12-01

    The state-of-the-art in the application of seismic isolation to industrial tanks is presented. Use of seismic isolation in industrial tanks can reduce lateral shaking forces by factors of 3 to 5 for strong earthquake loadings. This level of force reduction offers a practical and economical means of designing tanks on a linear elastic basis, and thereby reduces the risk of local failures and leakage during earthquakes. The case studies presented include: LNG Storage Tanks, an Ammonia Storage Tank, and an Emergency Fire and Cooling Water Tank. The tank capacities range from 50 thousand gallons to 19 million gallons. Two applications are new tanks, and one is a retrofit of an existing tank. The methodology for the design of the isolation bearings and tank structures is presented. The dynamic analysis methods used to perform the seismic analysis of the isolated tanks are reviewed, including the hydrodynamic modeling methods. The engineering principles and theory of the Friction Pendulum isolation bearings are discussed. This pendulum based isolation system results in the same natural period of vibration regardless of changes in the fluid levels in the tank, or temperature, aging, and environmental conditions. Test results for the isolation bearings are presented, including comparisons of experimental and analytical results for dynamic loadings, and strength, temperature and aging tests.

  9. Genetic differences between avian and human isolates of Candida dubliniensis.

    LENUS (Irish Health Repository)

    McManus, Brenda A

    2009-09-01

    When Candida dubliniensis isolates obtained from seabird excrement and from humans in Ireland were compared by using multilocus sequence typing, 13 of 14 avian isolates were genetically distinct from human isolates. The remaining avian isolate was indistinguishable from a human isolate, suggesting that transmission may occur between humans and birds.

  10. Fault Detection and Isolation for Spacecraft

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Wisniewski, Rafal

    2002-01-01

    This article realizes nonlinear Fault Detection and Isolation for actuators, given there is no measurement of the states in the actuators. The Fault Detection and Isolation of the actuators is instead based on angular velocity measurement of the spacecraft and knowledge about the dynamics of the...... satellite. The algorithms presented in this paper are based on a geometric approach to achieve nonlinear Fault Detection and Isolation. The proposed algorithms are tested in a simulation study and the pros and cons of the algorithms are discussed....

  11. Isolation of Chloroplasts from Plant Protoplasts.

    Science.gov (United States)

    Lung, Shiu-Cheung; Smith, Matthew D; Chuong, Simon D X

    2015-10-01

    Chloroplasts can be isolated from higher plants directly following homogenization; however, the resulting yield, purity, and intactness are often low, necessitating a large amount of starting material. This protocol is optimized to produce a high yield of pure chloroplasts from isolated Arabidopsis protoplasts. The two-part method is a simple, scaled-down, and low-cost procedure that readily provides healthy mesophyll protoplasts, which are then ruptured to release intact chloroplasts. Chloroplasts isolated using this method are competent for use in biochemical, cellular, and molecular analyses.

  12. Characterization of Sclerotinia sclerotiorum Isolated from Paprika

    OpenAIRE

    Jeon, Young-Jae; Kwon, Hyuk-Woo; Nam, Ji-Sun; Kim, Seong Hwan

    2006-01-01

    A fungal isolate collected from infected paprika (Capsicum annuum var. grossum) was characterized as Sclerotinia sclerotiorum based on its ability of sclerotium formation, physiological and molecular properties. When the isolate was grown on potato dextrose agar, oatmeal agar, and malt extract agar, it grew most well on PDA. Optimal temperature and pH for its growth were 25℃ and pH 7, respectively. The fungal isolate produced sclerotia on PDA within 10 days, and the color and shape of the scl...

  13. Mycoparasitism of Gliocladium isolates in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-hua; MA Gui-zhen; GAO Hui-lan; LI Shi-dong

    2004-01-01

    @@ During an investigation of mycoparasitic fungi on sclerotia of Sclerotinia sclerotiorum in China,Gliocladium species was consistently encountered and isolated from natural soils collected over the country. Colonization frequencies on sclerotia of S. sclerotiorum by the fungi ranged from 40% to 100% when the sclerotia were introduced into soils and coincubated at 22-24 ℃ for 4 weeks.Identification showed that G. roseum, G. virens and G. catenulatum were the dominant species among the 300 isolates gained. Molecular taxonomy of some Gliocladium isolates analysed by rDNA ITS sequence used ITS1 and ITS4 as primers was demonstrated to be identical with morphological classification.

  14. Ultrasonic isolation of buried pipes

    Science.gov (United States)

    Leinov, Eli; Lowe, Michael J. S.; Cawley, Peter

    2016-02-01

    Long-range guided wave testing (GWT) is used routinely for the monitoring and detection of corrosion defects in above ground pipelines. The GWT test range in buried, coated pipelines is greatly reduced compared to above ground configurations due to energy leakage into the embedding soil. In this paper, the effect of pipe coatings on the guided wave attenuation is investigated with the aim of increasing test ranges for buried pipelines. The attenuation of the T(0,1) and L(0,2) guided wave modes is measured using a full-scale experimental apparatus in a fusion-bonded epoxy (FBE)-coated 8 in. pipe, buried in loose and compacted sand. Tests are performed over a frequency range typically used in GWT of 10-35 kHz and compared with model predictions. It is shown that the application of a low impedance coating between the FBE layer and the sand effectively decouples the influence of the sand on the ultrasound leakage from the buried pipe. Ultrasonic isolation of a buried pipe is demonstrated by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both the pipe and sand, and has the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is found to be substantially reduced, in the range of 0.3-1.2 dB m-1 for loose and compacted sand conditions, compared to measured attenuation of 1.7-4.7 dB m-1 in the buried FBE-coated pipe without the PE-foam. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry and incorporated into model predictions of guided wave propagation in buried coated pipe. Good agreement is found between the experimental measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges; such

  15. Anreicherung, Isolierung und Analyse des Differenzierungsfaktors von Trypanosoma brucei

    OpenAIRE

    Buchholz, Björn

    2011-01-01

    Afrikanische Trypanosomen sind einzellige Parasiten, die bei Nutztieren die Nagana und bei Menschen die afrikanische Schlafkrankheit auslösen. Ihr Lebenszyklus ist durch einen obligaten Wirtswechsel zwischen Säuger und Tsetsefliege geprägt. Dabei wechseln sich teilungsfähige mit teilungsdefizienten Formen ab. Beim Stich einer infizierten Fliege werden metazyklische Trypanosomen von der Insekten-Speicheldrüse in die Blutbahn eines Vertebraten übertragen. Sie wandeln sich dann spontan in die...

  16. A case of familial isolated hemihyperplasia

    Directory of Open Access Journals (Sweden)

    Bacino Carlos A

    2004-02-01

    Full Text Available Abstract Background Hemihyperplasia (hemihypertrophy is defined as asymmetric body overgrowth of one or more body parts. Hemihyperplasia can be isolated or be part of well-defined syndromes such as in the case of Beckwith-Wiedemann syndrome (BWS. Isolated hemihyperplasia is usually sporadic, but a number of familial occurrences have been described. Case presentation We describe a Tunisian family in which three maternal cousins and their maternal grandfather present with isolated hemihyperplasia. Conclusions The etiology of isolated hemihyperplasia is unknown although in BWS, genomic imprinting has been shown to play a role in the asymmetric overgrowth. Given the similarity between these two conditions, it is possible that both may share a common pathogenesis. We also discuss the possible genetic mechanisms leading to the production of hemihyperplasia in this family.

  17. Pendulum seismic isolation bearings. Design, analysis, experiment

    Directory of Open Access Journals (Sweden)

    Yu.L. Rutman

    2012-02-01

    Full Text Available In the present research a pendular type of seismoisolation system for protection construction from earthquake is considered. Seismic isolation is carried out on the basis of the following principles:• the natural frequency of the "protected object - seismic isolation" should be significantlylower than the main energy contained frequency (which leads to high frequencies filtering;• damping in seismic isolation systems should be high enough to avoid resonance effects;• in seismic isolation systems can be applied elements that limit the level of force that is passed to the protected object (a plastically deformable or friction elements.A design of devices (component of seismoisolation systems is shown in the article. The methods of seismoisolation systems analysis are described and the results are presented. The main results of dynamic tests of those devices are shown.

  18. Antigenic typing Polish isolates of canine parvovirus

    Energy Technology Data Exchange (ETDEWEB)

    Mizak, B. [National Veterinary Research Institute, Pulawy (Poland); Plucienniczak, A. [Polish Academy ofd Sciences. Microbiology and Virology Center, Lodz (Poland)

    1995-12-31

    Polish strains of canine parvovirus isolated between 1982 and 1993 were examined to determine the extent to which the virus has evolved antigenically and genetically over eleven years. Two CPV isolates obtained in Warsaw in 1982 and Pulawy in 1993, were examined using monoclonal antibody typing, restriction analysis and sequencing VP-2 protein gene. Five other isolates from Warsaw and Pulawy were tested with the panel of monoclonal antibodies specific to CPV-2, CPV-2a and common for canine parvovirus, feline panleukopenia virus and milk enteritis virus. Results of the studies demonstrated that all isolates tested represented CPV-2a antigenic type. Rapid antigenic strain replacement recorded by Parrish and Senda in the U.S.A and Japan was not confirmed in Poland. (author). 30 refs, 2 tabs.

  19. Spontaneously reduced isolated orbital roof fracture.

    Science.gov (United States)

    Itinteang, Tinte; Lambe, Gerald Francis; MacKinnon, Craig; Agir, Hakan

    2012-07-01

    We report a case of a spontaneously reduced isolated orbital roof blow-in fracture with resolution of associated diplopia and blepharoptosis highlighting the need for a low threshold for reimaging this cohort of facial fracture patients. PMID:22801127

  20. ISOLATION OF RUTIN FROM PHYLLANTHUS AMARUS

    Directory of Open Access Journals (Sweden)

    Prabodh Shukla et al.

    2012-04-01

    Full Text Available General phytochemical screening of Phyllanthus amarus (Euphorbiaceae revealed the presence of Saponin, tannins, glycoside and alkaloids etc. The aim of this study is to identify and characterize the bioactive principle from the plant. It has wide folk medicinal uses. The isolation and characterization of Phytoconstituent was done from the methanolic extract by the gradient fractionation method. The structure of the isolated compound was established on the basis of physical, chemical test and spectroscopic evidences (IR, UV, 1HNMR, MS. A flavonol structure was isolated from the methanolic extract of the plant. The odourless, colourless compound which solubilizes in methanol having m.p. 1860C and Rf value 0.46 in mobile phase Methanol : Glacial Acetic Acid: Water (90 : 5 : 5 was identified by the various spectroscopical methods. So from this study it is concluded that isolated compound may be rutin which is responsible for various pharmacological activities of the plant.

  1. Isolated Curves for Hyperelliptic Curve Cryptography

    CERN Document Server

    Wang, Wenhan

    2012-01-01

    We introduce the notion of isolated genus two curves. As there is no known efficient algorithm to explicitly construct isogenies between two genus two curves with large conductor gap, the discrete log problem (DLP) cannot be efficiently carried over from an isolated curve to a large set of isogenous curves. Thus isolated genus two curves might be more secure for DLP based hyperelliptic curve cryptography. We establish results on explicit expressions for the index of an endomorphism ring in the maximal CM order, and give conditions under which the index is a prime number or an almost prime number for three different categories of quartic CM fields. We also derived heuristic asymptotic results on the densities and distributions of isolated genus two curves with CM by any fixed quartic CM field. Computational results, which are also shown for three explicit examples, agree with heuristic prediction with errors within a tolerable range.

  2. Connectivity and Linkages Between Isolated Habitat

    Data.gov (United States)

    California Department of Resources — Proposed areas where connectiviy and linkages between isolated habitat on the San Joaquin Valley floor and natural lands in the surrounding foothills should be...

  3. Nitrogen uptake kinetics of freshly isolated zooxanthellae

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Wafar, S.; Rajkumar, R.

    Zooxanthellae freshly isolated from the coral host Pocillopora damicornis exhibited substrate-saturable uptake kinetics for ammonium, nitrate and urea. Maximum uptake velocity for ammonium [10.1 nmol. ( mu chl-a)./1h/1] was greater than...

  4. Extracellular enzymatic activities of Bipolaris sorokiniana isolates.

    Science.gov (United States)

    Geimba, Mercedes P; Brandelli, Adriano

    2002-01-01

    Several enzymatic activities were investigated in six isolates of the fungus Bipolaris sorokiniana, originating from different areas of Brazil. Among the glycosidases studied, beta-glucosidase, beta-N-acetylglucosaminidase, beta-xylosidase, cellobiohydrolase, and chitobiohydrolase were the major activities. In some isolates, beta-glucuronidase, beta-galactosidase, and alpha-mannosidase activities were also present. Polysaccharide-hydrolyzing enzymes, such as pectin lyase and carboxymethyl cellulase were detected in significant amounts, and their activities were variable among the different isolates. Other enzymes, namely phosphatases, proteinases and phenol oxidase, were also examined, showing variable amounts depending on the isolate. The pH dependence of all enzymes tested was investigated. Endoproteinase, carboxymethyl cellulase, and phenoloxidase had maximum activity in the pH range of 6-8, whilst all other enzymes showed maximum activity at pH 4-6.

  5. Neglected isolated fracture of the trochlea humeri

    Institute of Scientific and Technical Information of China (English)

    Ajay Pal Singh; Ish Kumar Dhammi; Anil Kumar Jain; Saurabh Jain

    2010-01-01

    A 15 years old girl was found to have isolated trochlea fracture 10 weeks after an injury caused by a fall on her left elbow. Movement of the elbow was severely restricted. Radiographs showed a half moon-shaped and anterosuperiorly displaced osteochondral fragment. Medial approach capsulotomy of the elbow and excision of the intraarticular adhesions were done to expose the isolated trochlea fracture. Headless screws were used for fixation,combined with bone grafting. The follow-up showed union and excellent functional recovery of the elbow. Isolated trochlea fracture in adults is rare and usually associated with capitellar fractures and/or elbow dislocations. A neglected trochlea fracture is rarely reported in the English language literature to the best of our knowledge. Recognition of isolated trochlea fracture is vital to apprehend the pathomechanics of the injury and to devise a suitable treatment approach.

  6. The dynamics of isolated Local Group galaxies

    CERN Document Server

    Kirby, Evan N; Boylan-Kolchin, Michael; Kaplinghat, Manoj; Cohen, Judith G

    2014-01-01

    We measured velocities of 862 individual red giant stars in seven isolated dwarf galaxies in the Local Group: NGC 6822, IC 1613, VV 124 (UGC 4879), the Pegasus dwarf irregular galaxy (DDO 216), Leo A, Cetus, and Aquarius (DDO 210). We also computed velocity dispersions, taking into account the measurement uncertainties on individual stars. None of the isolated galaxies is denser than the densest Local Group satellite galaxy. Furthermore, the isolated dwarf galaxies have no obvious distinction in the velocity dispersion--half-light radius plane from the satellite galaxies of the Milky Way and M31. The similarity of the isolated and satellite galaxies' dynamics and structural parameters imposes limitations on environmental solutions to the too-big-to-fail problem, wherein there are fewer dense dwarf satellite galaxies than would be expected from cold dark matter simulations. This data set also has many other applications for dwarf galaxy evolution, including the transformation of dwarf irregular into dwarf sphe...

  7. Compact, Lightweight, High Voltage Propellant Isolators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TA&T, Inc. proposes an enabling fabrication process for high voltage isolators required in high power solar electric and nuclear electric propulsion (SEP and...

  8. A Multiport Isolated DC-DC Converter

    OpenAIRE

    Tran, Yan-Kim; Dujic, Drazen

    2016-01-01

    This paper presents a multi-port isolated DC-DC converter for DC applications. A three-port structure is presented, characterized with full bidirectional power flow and simple control. Galvanic isolation is achieved by means of a multi-winding medium frequency transformer which is a part of a resonant LLC converter. To provide controllable power exchange with external DC ports, two out of three ports are equipped with additional bidirectional buck/boost stages. They serve to provide active po...

  9. Combating isolation: Building mutual mentoring networks

    Science.gov (United States)

    Cox, Anne J.

    2015-12-01

    Women physicists can often feel isolated at work. Support from a grant through the ADVANCE program of the National Science Foundation (U.S. government funding) created mutual mentoring networks aimed at combating isolation specifically for women faculty at undergraduate-only institutions. This paper will discuss the organization of one such network, what contributed to its success, some of the outcomes, and how it might be implemented in other contexts.

  10. Isolation and damping properties of magnetorheologic elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Collette, C; Kroll, G; Avraam, M; Preumont, A [University of Brussels, 50 av. F.D. Roosevelt, 1050 Brussels (Belgium); Saive, G [Techspace Aero (SAFRAN Group), 121, route de Liers, 4041 Herstal (Belgium); Guillemier, V [MATIS Benelux, 121, route de Liers, 4041 Herstal (Belgium)], E-mail: christophe.collette@ulb.ac.be

    2009-02-01

    This paper considers two systems based on a magnetorheological elastomer (MRE): a MRE isolator under a frequency varying harmonic excitation and a MRE Dynamic Vibration Absorber (DVA) mounted on a frequency-varying structure under a random excitation. It is shown that the commandability of the elastomer improves the isolation performances in the first case, and decreases the stress level in the structure in the second case.

  11. Fault Detection and Isolation using Eigenstructure Assignment

    DEFF Research Database (Denmark)

    Jørgensen, R.B.; Patton, R.J.; Chen, J.

    1994-01-01

    The purpose of this article is to investigate the robustness to model uncertainties of observer based fault detection and isolation. The approach is designed with a straight forward dynamic nad the observer.......The purpose of this article is to investigate the robustness to model uncertainties of observer based fault detection and isolation. The approach is designed with a straight forward dynamic nad the observer....

  12. An isolated vaginal metastasis from rectal cancer

    OpenAIRE

    Ai Sadatomo; Koji Koinuma; Hisanaga Horie; Lefor, Alan K.; Naohiro Sata

    2015-01-01

    Introduction: Isolated vaginal metastases from colorectal cancer are extremely rare. There are only a few reported cases in the English literature, and the characteristics of such cases of metastasis remain relatively unknown. Presentation of case: We present a case of isolated vaginal metastasis from rectal cancer in a 78-year-old female patient. The patient had no symptoms related to vaginal tumor. Magnetic resonance imaging (MRI) showed thickening of the middle rectum and a vaginal tumo...

  13. ASSESING GEOGRAPHIC ISOLATION OF THE GALAPAGOS ISLANDS

    OpenAIRE

    Orellana, D.; Smith, F.

    2016-01-01

    The Galapagos Archipelago is one of the most important ecological spots in the planet due its unique biodiversity, active geology, and relatively well-preserved ecosystems. These characteristics are strongly based on the geographical isolation of the islands. On the one hand this isolation allowed the evolution processes that gave the islands their international fame and on the other hand it kept them from major human impacts that affected the vast majority of the Earth’s surface. Ga...

  14. Criteria: waste tank isolation and stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Metz, W.P.; Ogren, W.E.

    1976-09-01

    The crystallized Hanford high-level wastes stored in single-shell underground tanks consist of sludges and salt cakes covered with supernatural liquor. Purpose of stabilization and isolation is to reduce the releases and losses as a result of a loss of tank integrity. The tanks will be modified so that no inadvertent liquid additions can be made. Criteria for the isolation and stabilization are given and discussed briefly. (DLC)

  15. Complete Isolation System for Laboratory Infectious Animal

    Institute of Scientific and Technical Information of China (English)

    Jean; Pierre

    2005-01-01

    Contents:Duringthe development of biological medical science,a great number of research experiments are carried out andthe various infectious animal experiments are necessary part of them.For lab animal experiments,it is necessary tochoose proper isolation equipments accordingto experiment hazardlevels.1.FunctionsAnimal isolation systemare used broadlyin laboratory research,pharmaceuticals and medical areas.The isolationsystemhas become excellent equipmentsin animal breeding,disease diagnosis,analysis,test ...

  16. Genotoxicological Evaluation of NUTRALYS Pea Protein Isolate

    OpenAIRE

    Chentouf Aouatif; Ph. Looten; Parvathi, M. V. S.; Raja Ganesh, S.; Paranthaman, V

    2013-01-01

    NUTRALYS Pea Protein Isolate, a protein supplement, is a high-quality source of protein which is primarily emulsifying functional protein. We evaluated the genotoxic potential of NUTRALYS isolated from dry yellow pea, using three established genotoxicity tests (AMES test in vitro chromosomal aberration test, and in vivo micronucleus test) employing OECD guidelines under GLP conditions. In the bacterial reverse mutation test, NUTRALYS did not show positive responses in strains detecting point ...

  17. Isolated rib fractures in geriatric patients

    OpenAIRE

    Elmistekawy Elsayed; Hammad Abd Almohsen

    2007-01-01

    Introduction: The goal of this study was to investigate the short-term outcomes in patients older than 60 years with isolated rib fractures and admitted to emergency hospital. Materials and Methods: This study included patients who were 60 years old or more and sustained blunt chest injury and had isolated rib fractures. The following data were obtained from the medical records: age, gender, number of fracture ribs, side of fracture ribs, mechanism and nature of injury, preexisting medical...

  18. An isolated current monitor for iontophoresis.

    Science.gov (United States)

    Hauser, S E; Cohen, S A

    1976-01-01

    An inexpensive isolated current monitor has been developed as an effort to minimize stimulus artifact in experimental systems which include iontophoresis as the source of stimulus. The monitor becomes an element of the iontophoresis circuit, but provides an output voltage isolated from the iontophoresis current. The voltage is proportional to the iontophoresis current and will represent currents of 1/2 nA to 5 muA. It is this ability to detect minute currents that is valuable in iontophoresis measurements.

  19. Candida species isolated from various clinical specimens

    OpenAIRE

    Uraz, Güven; Arslan, Seza; Ekener, Serpil

    2000-01-01

    Objectives: The various culture specimens of patients were investigated in our research. Material and methods: 123 Candida strains were isolated. In identification of Candida species that were isolated, germ tube test, growth in Cornmeal-Tween 80 agar and formation of clamydospore, presence of pseudohyphae, carbonhytrate fermentation and assimilation tests, formation of membranes in sabouraud medium, and the tests of ascospore in the mediums with cycloheximide and the test of nitrate were...

  20. Rebate subsidies, matching subsidies and isolation effects

    Directory of Open Access Journals (Sweden)

    Douglas D. Davis

    2006-07-01

    Full Text Available In a series of recent experiments (Davis, Millner and Reilly, 2005, Eckel and Grossman, 2003, 2005a-c, 2006, matching subsidies generate significantly higher charity receipts than do theoretically equivalent rebate subsidies. This paper reports a laboratory experiment conducted to examine whether the higher receipts are attributable to a relative preference for matching subsidies or to an ``isolation effect'' (McCaffery and Baron, 2003, 2006. Some potential policy implications of isolation effects on charitable contributions are also

  1. Gene Diversity of Trichomonas vaginalis Isolates

    OpenAIRE

    Z Valadkhani; F Kazemi; N Hassan; Aghighi, Z; I Esmaili; M. Talebi2

    2011-01-01

    Background: Trichomonas vaginalis is protozoan parasite responsible for trichomoniasis and is more common in high-risk behavior group such as prostitute individuals. Interest in trichomoni­asis is due to increase one's susceptibility to viruses such as herpes, human papillomavirus and HIV. The aim of this study was to find genotypic differences between the isolates.Methods: Forty isolates from prisoners' women in Tehran province were used in this study. The random amplified polymorphic DNA (R...

  2. Seismic isolation, the New Zealand experience

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, W.H. [New Zealand Inst. for Industrial Research and Development, Lower Hutt (New Zealand). Materials Engineering Lab.

    1995-12-01

    In New Zealand, seismic isolation, the technique in which the structure is decoupled from earthquake-induced ground motions, has now advanced to the point where it is often considered for the protection of both new and existing buildings, bridges, and to a lesser extent, industrial plant. The authors describe here how the lead-based devices operate, and they give some examples of the application of seismic isolation to structures in New Zealand. Current interest is focused on the application of seismic isolation to three buildings in central Wellington. In July 1993, the construction of the seismically isolated Museum of New Zealand was started on the Wellington waterfront. All of the lead-rubber isolators have now (June 1994) been tested, delivered to the site and most have been installed. Nearby the NZ Parliament Building and Library have been retrofitted with a lead-rubber bearing system. To support the continuation of improvements to the seismic resistance of structures a number of research programs are operating in the Universities of Auckland and Canterbury, the Engineering Seismology Section of the NZ Institute of Geology, Works, a number of engineering consultants and in the author`s own institute. Very strong support for the principles of seismic isolation is given by the fact that of the ten hospitals affected by the recent Los Angeles (Jan `94) earthquake only the hospital seismically isolated by a lead-rubber bearing system was able to continue to operate. Further support is given by the excellent behavior of two isolated buildings in the South Hyogo earthquake (Jan. `95).

  3. Using Isolation Spheres for Cooperative Processes Correctness

    OpenAIRE

    Guabtni, Adnene; Charoy, François; Godart, Claude

    2006-01-01

    Managing cooperation in Business Processes still represents a challenge because of several problems. Concurrent access to common data, coherence of the results, organisation and cooperation correctness are some of them. Looking at isolation problems in the database world and at their solutions using SQL isolation levels, we try to adapt them to the cooperative dimension of processes. In this paper, we identify the phenomena that happen during cooperation in business processes. Then we propose...

  4. Effects of Metallothionein on Isolated Rat Heart

    Institute of Scientific and Technical Information of China (English)

    SUN Zhongdong; XIA Jiahong; DONG Nianguo; DU Xinling; CHI Yifan; YANG Tienan; YANG Chenyuan

    2007-01-01

    To investigate the effects of metallothionein (MT) on isolated rat heart, 16 Wistar rats were randomly divided into 2 groups. In control group (group C), distilled water was injected intraperitoneally and 24 h later isolated hearts were perfused with Langendorff and stored at 4℃ for 3 h with histidine-tryptophan-ketoglutarate (HTK) solutions, and then isolated hearts were perfused for 2 h by Langendorff. In experimental group (group E), 3.6% ZnSO4 was injected intraperitoneally, 24 h later isolated hearts were perfused by Langendorff and stored at 4℃ for 3 h with HTK solutions, and then the isolated herts were perfused for 2 h with Langendorff. MT content, the recovery of hemodynamics, myocardial water content (MWC), lactate dehydrogenase (LDH) and creatine kinase (CK) leakage, adenosine triphosphate (ATP) and malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, myocardial cell Ca2+ content, Ca2+-ATPase activity of mitochondria ([Ca2+-ATPase]m) and its Ca2+ content ([Ca2+]m), synthesizing ATP activity of mitochondria ([ATP]m), and the ultrastructure of cells were examined. There were a significant increase in group E in hemodynamic recovery, ATP content, SOD activity, [Ca2+-ATPase]m activity, [ATP]m activity, and substantial reduction in MWC, LDH and CK leakage, MDA content, myocardial cell Ca2+ content, [Ca2+]m content,and the ultrastructural injury were obviously milder than that of group C. This study demonstrated that MT has protective effects on isolated rat heart.

  5. Seismic behavior of variable frequency pendulum isolator

    Institute of Scientific and Technical Information of China (English)

    V. R. Panchal; R. S. Jangid

    2008-01-01

    Earthquake performance of a flexible one-story building isolated with a variable frequency pendulum isolator(VFPI) under near-fault and far-field ground motions is investigated. The frictional forces mobilized at the interface of theVFPI are assumed to be velocity dependent. The interaction between frictional forces of the VFPI in two horizontal directionsis duly considered and coupled differential equations of motion of the isolated system in the incremental form are solvediteratively. The response of the system with bi-directional interaction is compared with those without interaction. In addition,the effects of velocity dependence on the response of the isolated system are also investigated. Moreover, a parametricstudy is carried out to critically examine the influence of important parameters on bi-directional interaction effects of thefrictional forces of the VFPI. These parameters are: the superstructure time period, frequency variation factor (FVF) andfriction coefficient of the VFPI. From the above investigations, it is observed that the dependence of the friction coefficienton relative velocity of the system does not have a noticeable effect on the peak response of the system isolated with VFPI, andthat the bi-directional interaction of frictional forces of the VFPI is important and if neglected, isolator displacements will beunderestimated and the superstructure acceleration and base shear will be overestimated.

  6. Isolation of cellulose microfibrils - An enzymatic approach

    Directory of Open Access Journals (Sweden)

    Sain, M.

    2006-11-01

    Full Text Available Isolation methods and applications of cellulose microfibrils are expanding rapidly due to environmental benefits and specific strength properties, especially in bio-composite science. In this research, we have success-fully developed and explored a novel bio-pretreatment for wood fibre that can substantially improve the microfibril yield, in comparison to current techniques used to isolate cellulose microfibrils. Microfibrils currently are isolated in the laboratory through a combination of high shear refining and cryocrushing. A high energy requirement of these procedures is hampering momentum in the direction of microfibril isolation on a sufficiently large scale to suit potential applications. Any attempt to loosen up the microfibrils by either complete or partial destruction of the hydrogen bonds before the mechanical process would be a step forward in the quest for economical isolation of cellulose microfibrils. Bleached kraft pulp was treated with OS1, a fungus isolated from Dutch Elm trees infected with Dutch elm disease, under different treatment conditions. The percentage yield of cellulose microfibrils, based on their diameter, showed a significant shift towards a lower diameter range after the high shear refining, compared to the yield of cellulose microfibrils from untreated fibres. The overall yield of cellulose microfibrils from the treated fibres did not show any sizeable decrease.

  7. Hyaluronidase in Clinical Isolates of Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Harmony Tyner

    2015-01-01

    Full Text Available Objectives. We sought to describe the prevalence of a hyaluronidase gene and hyaluronidase production in 197 clinical isolates of P. acnes; we assessed kinetics of hyaluronidase production in a subset of three isolates. Methods. The hyaluronidase gene was detected using polymerase chain reaction. Hyaluronidase production was detected by growing isolates on BHI agar containing 400 μg/mL hyaluronic acid and 1% albumin and flooding plates with 2 N glacial acetic acid to precipitate unbound hyaluronic acid, with a zone of clearing representing a positive phenotype. Hyaluronidase production kinetics were measured as a function of hyaluronic acid digestion over time in a liquid medium. Results. A hyaluronidase gene and hyaluronidase production were detected in 100 and 97% of P. acnes isolates, respectively. Hyaluronidase production in liquid medium was detectable after 96 hours of growth. Conclusions. Hyaluronidase production is nearly universal among P. acnes isolates. Three days appear to be required for significant hyaluronidase production in a liquid medium. Detection of hyaluronidase in tissue specimens may be a strategy to differentiate P. acnes infection from colonization when P. acnes is isolated from a clinical specimen.

  8. Forty Years of Research on Isolated Galaxies

    CERN Document Server

    Sulentic, J W

    2009-01-01

    Isolated galaxies have not been a hot topic over the past four decades. This is partly due to uncertainties about their existence. Are there galaxies isolated enough to be interesting? Do they exist in sufficient numbers to be statistically useful? Most attempts to compile isolated galaxy lists were marginally successful--too small number and not very isolated galaxies. If really isolated galaxies do exist then their value becomes obvious in a Universe where effects of interactions and environment (i.e. nurture) are important. They provide a means for better quantifying effects of nurture. The Catalog of Isolated Galaxies (CIG) compiled by Valentina Karachentseva appeared near the beginning of the review period. It becomes the focus of this review because of its obvious strengths and because the AMIGA project has increased its utility through a refinement (a vetted CIG). It contains almost 1000 galaxies with nearest neighbor crossing times of 1-3Gyr. It is large enough to serve as a zero-point or control samp...

  9. Isolation and resistance test of several isolates of Lactobacillus in low pH

    Directory of Open Access Journals (Sweden)

    RIANI HARDININGSIH

    2006-01-01

    Full Text Available Several isolates of Lactobacillus had been isolated from Indonesian fermented foods. Four isolates where isolated from tongcai (TT2, saguer drink (Sg.Mnd.N2, pindang ikan selar (PSl1 and sawi asin (S5 had been used in this research. The aim of the research was to get Lactobacillus isolates as probiotic candidate and to know its resistance to low pH. The treatment were several concentration of low pH of MRS broth medium, i.e. 2; 2.5; 3; and 6.5 (optimal pH. The optical density (OD was measured after 24, 48, 72, and 96 hours respectively, with three replication by using spectrophotometer ( = 600 nm. The results showed that all Lactobacillus isolates (i.e. TT2, Sg.Mnd.N2, PSl1, and S5 could been used as probiotic candidate because they were resistant to all of low pH used.

  10. Yeasts isolated from clinical samples of AIDS patients

    Directory of Open Access Journals (Sweden)

    Neves Rejane Pereira

    2002-01-01

    Full Text Available In order to investigate yeasts in oropharyngeal secretion, urine, sputum and inguinal scales from AIDS patients, clinical samples were collected from one hundred patients interned in the Infectious and Parasitic Diseases Sector of the Hospital das Clínicas of the Universidade Federal de Pernambuco and in Hospital Universitário Osvaldo Cruz of the Universidade de Pernambuco. Yeasts were isolated from seventy-two out of one hundred and eight clinical samples. The isolated yeasts were: Candida albicans (sixty-two isolates, Candida tropicalis (four isolates, Candida glabrata (two isolates, Candida parapsilosis (two isolates, Candida krusei (one isolate and Trichosporon pullulans (one isolate.

  11. Applicability of base isolation made of elastomeric isolators for the protection of cultural heritage

    OpenAIRE

    Vojko Kilar; David Koren; Simon Petrovčič

    2009-01-01

    This article briefly presents the applicability of base isolation made of elastomeric isolators for the protection of heritage architecture. The first part of the article gives an illustrative overview on the use of base isolation throughout the world, together with an analysis of guidelines for the protection and management of places of heritage architecture. The guidelines which are given through international agreements and resolutions on the conservation of monuments have to be considered...

  12. Isolation and characterization of Vibrio cholerae isolates from seafood in Hat Yai City, Songkhla, Thailand.

    Science.gov (United States)

    Preeprem, Sutima; Mittraparp-arthorn, Pimonsri; Bhoopong, Phuangthip; Vuddhakul, Varaporn

    2014-11-01

    Seafood has been identified as an important source of Vibrio cholerae in Thailand, especially in the Southern coastal region. In this study, we isolated and characterized V. cholerae from seafood obtained from several markets in Hat Yai city, Southern Thailand. A total of 100 V. cholerae isolates were obtained from 55 of 125 seafood samples. The dominant serotype was non-O1/non-O139. Polymerase chain reaction (PCR) analysis was used to detect the presence of pathogenesis-related genes. The stn/sto and hlyA El Tor virulence genes were detected in 20% and 96% of the isolates, respectively. None of the isolates were positive for the ctxA, tcpA, zot, and ace genes. Only 6% of the isolates carried the T3SS gene (vcsV2); however, the majority of the isolates (96%) carried the T6SS gene (vasH). Representative isolates (n=35) that exhibited various virulence gene patterns were randomly selected and analyzed for their hemolytic activity, antibiotic susceptibility, biofilm formation, and genotype. Hemolytic activity using sheep red blood cells was detected in only one of the hlyA-negative isolates. Apart from ampicillin, all isolates were pansusceptible to five test antibiotics. Biofilm production was observed in most of the isolates, and there was no difference in the presence of a biofilm between the smooth and rugose isolates. Using the enterobacterial repetitive intergenic consensus-PCR method, clonal relationships were observed among the isolates that exhibited identical virulence gene patterns.

  13. Isolation and screening of azo dye decolorizing bacterial isolates from dye-contaminated textile wastewater

    OpenAIRE

    Shahid Mahmood; Muhammad Arshad; Azeem Khalid; Zilli Huma Nazli; Tariq Mahmood

    2011-01-01

    Azo dyes are released into wastewater streams without any pretreatment and pollute water and soilenvironments. To prevent contamination of our vulnerable resources, removal of these dye pollutants is of greatimportance. For this purpose, wastewater samples were collected from dye-contaminated sites of Faisalabad. About200 bacterial isolates were isolated through enrichment and then tested for their potential to remove RemazolBlack-B azo dye in liquid medium. Five bacterial isolates capable of...

  14. Isolation and Characterization of Tetracycline-Resistant Clinical Isolates of Helicobacter pylori

    OpenAIRE

    Kwon, Dong H.; Kim, J.J.; Lee, M.; Yamaoka, Y.; Kato, M; Osato, M. S.; El-Zaatari, F. A. K.; David Y Graham

    2000-01-01

    Tetracycline is an important component of combination therapies for Helicobacter pylori eradication. Twenty-nine tetracycline-resistant isolates requiring MICs ranging from 4 to 16 μg/ml were isolated from Korean (22 of 460) and Japanese (7 of 105) patients. Interestingly, all of the 29 tetracycline-resistant isolates exhibited cross-resistance to metronidazole, and the cross-resistance was transferred to tetracycline-sensitive H. pylori strains.

  15. Exopolysaccharide Production by Four Cyanobacterial Isolates and Preliminary Identification of These Isolates

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yunyi; CHI Zhenming; LU Weidong

    2007-01-01

    Four marine cyanobacterial isolates, named 104, 109, 113 and 115, from marine water off China's coast can release a large amount of exopolysaccharide (EPS) to medium. The effects of different components in medium on EPS production by the four isolates were investigated. Under the optimal condition, the EPS released by isolates 104,109, 113 and 115 reached 7.48 g L-1, 8.33 g L-1, 18.26 g L-1, and 6.78 g L-1 within 14 d,respectively. Based on the conventional identification methods for cyanobacteria,these isolates were assigned to genus Cyanothece.

  16. Single spore isolation and morphological characterization of local Malaysian isolates of rice blast fungus Magnoporthe grisea

    Science.gov (United States)

    Mishra, Ankitta; Ratnam, Wickneswari; Bhuiyan, Md Atiqur Rahman; Ponaya, Ariane; Jena, Khisord K.

    2015-09-01

    Rice blast is a destructive disease, caused by the fungal pathogen Magnaporthe grisea. It causes considerable damage to rice and leads to crop loss in rice growing regions worldwide. Although fungicides can be used to control rice blast, they generate additional cost in rice production and contamination of environment and food. Therefore, the use of resistant varieties is thought to be one of the most economically and environmentally efficient ways of crop protection from the disease. Six new local Malaysian isolates of M. grisea were isolated using single spore isolation method. Five isolates were from infected leaf samples collected from Kompleks Latihan MADA, Kedah and one was from Kelantan. These isolates were identified using morphological characteristics and microscopic studies and later confirmed by ITSequences. These isolates were induced to sporulate and used for greenhouse screening on two differential rice varieties: Mahsuri (susceptible) and Pongsu Seribu 2 (resistant). Among the 6 isolates, isolate number 3 was found to be the most virulent showing high sporulation while isolate number 4 was very slow growing, and the least virulent.

  17. Permanent isolation surface barrier development plan

    International Nuclear Information System (INIS)

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no open-quotes provenclose quotes long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems

  18. Permanent isolation surface barrier development plan

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.

    1994-01-01

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no {open_quotes}proven{close_quotes} long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems.

  19. Isolation of Campylobacter from human stool samples

    Directory of Open Access Journals (Sweden)

    S M Salim

    2014-01-01

    Full Text Available Context: Campylobacter is an undetected cause of diarrhoea especially under 5 years of age in most of the countries. Isolation of this organism is difficult, expensive and cumbersome. Aims: Our objective of this study was to isolate this pathogen from the stool specimens on routinely available blood containing laboratory media using the candle jar for creating the microaerophilic atmosphere in our setup. Settings and Designs: A descriptive study. Materials and Methods: A total of 50 stool samples were inoculated onto selective and non-selective media with and without filtration using a 0.45 μm membrane. The inoculated media were simultaneously incubated in microaerophilic conditions using the Anoxomat as well as in candle jars at temperatures 37°C and 42°C. The culture isolates were confirmed by standard phenotypic tests. A simplex polymerase chain reaction (PCR targeting the 16S ribosomal deoxyribonucleic acid of Campylobacter was performed on the deoxyribonucleic acid (DNA of the culture isolates as well as on the DNA extracted from the stool filtrates. Statistical Analysis: Data was expressed as a proportion. Results: Campylobacter could be isolated in 5 out of 50 stool samples using both the Anoxomat as well as the candle jar. Furthermore, we did not find any difference between the isolation using the selective and blood containing media as well as the different incubation temperatures. All the five were confirmed phenotypically and genotypically to be Campylobacter jejuni. The PCR results corroborated with that of the culture. Conclusions: Isolation by culture was as sensitive as that of the PCR.

  20. Legionella spp. isolation and quantification from greywater.

    Science.gov (United States)

    Rodríguez-Martínez, Sara; Blanky, Marina; Friedler, Eran; Halpern, Malka

    2015-01-01

    Legionella, an opportunistic human pathogen whose natural environment is water, is transmitted to humans through inhalation of contaminated aerosols. Legionella has been isolated from a high diversity of water types. Due its importance as a pathogen, two ISO protocols have been developed for its monitoring. However, these two protocols are not suitable for analyzing Legionella in greywater (GW). GW is domestic wastewater excluding the inputs from toilets and kitchen. It can serve as an alternative water source, mainly for toilet flushing and garden irrigation; both producing aerosols that can cause a risk for Legionella infection. Hence, before reuse, GW has to be treated and its quality needs to be monitored. The difficulty of Legionella isolation from GW strives in the very high load of contaminant bacteria. Here we describe a modification of the ISO protocol 11731:1998 that enables the isolation and quantification of Legionella from GW samples. The following modifications were made:•To enable isolation of Legionella from greywater, a pre-filtration step that removes coarse matter is recommended.•Legionella can be isolated after a combined acid-thermic treatment that eliminates the high load of contaminant bacteria in the sample. PMID:26740925

  1. Seismic Analysis of a Viscoelastic Damping Isolator

    Directory of Open Access Journals (Sweden)

    Bo-Wun Huang

    2015-01-01

    Full Text Available Seismic prevention issues are discussed much more seriously around the world after Fukushima earthquake, Japan, April 2011, especially for those countries which are near the earthquake zone. Approximately 1.8×1012 kilograms of explosive energy will be released from a magnitude 9 earthquake. It destroys most of the unprotected infrastructure within several tens of miles in diameter from the epicenter. People can feel the earthquake even if living hundreds of miles away. This study is a seismic simulation analysis for an innovated and improved design of viscoelastic damping isolator, which can be more effectively applied to earthquake prevention and damage reduction of high-rise buildings, roads, bridges, power generation facilities, and so forth, from earthquake disaster. Solidworks graphic software is used to draw the 3D geometric model of the viscoelastic isolator. The dynamic behavior of the viscoelastic isolator through shock impact of specific earthquake loading, recorded by a seismometer, is obtained via ANSYS finite element package. The amplitude of the isolator is quickly reduced by the viscoelastic material in the device and is shown in a time response diagram. The result of this analysis can be a crucial reference when improving the design of a seismic isolator.

  2. Legionella spp. isolation and quantification from greywater

    Science.gov (United States)

    Rodríguez-Martínez, Sara; Blanky, Marina; Friedler, Eran; Halpern, Malka

    2015-01-01

    Legionella, an opportunistic human pathogen whose natural environment is water, is transmitted to humans through inhalation of contaminated aerosols. Legionella has been isolated from a high diversity of water types. Due its importance as a pathogen, two ISO protocols have been developed for its monitoring. However, these two protocols are not suitable for analyzing Legionella in greywater (GW). GW is domestic wastewater excluding the inputs from toilets and kitchen. It can serve as an alternative water source, mainly for toilet flushing and garden irrigation; both producing aerosols that can cause a risk for Legionella infection. Hence, before reuse, GW has to be treated and its quality needs to be monitored. The difficulty of Legionella isolation from GW strives in the very high load of contaminant bacteria. Here we describe a modification of the ISO protocol 11731:1998 that enables the isolation and quantification of Legionella from GW samples. The following modifications were made:•To enable isolation of Legionella from greywater, a pre-filtration step that removes coarse matter is recommended.•Legionella can be isolated after a combined acid-thermic treatment that eliminates the high load of contaminant bacteria in the sample. PMID:26740925

  3. Extremely Isolated Early-Type Galaxies

    Science.gov (United States)

    Fuse, Christopher; Marcum, Pamela; Fanelli, Michael

    2006-10-01

    Isolated galaxies provide a unique means of assessing the evolution of galactic systems. Extremely isolated galaxies define the zero-interaction baseline for comparative studies of galaxy evolution. Here we present results for a sample of isolated early-type galaxies (IEGs) in the local universe. Candidate IEGs were identified using the optical imaging data from Release 1-5 of the Sloan Digital Sky Survey (SDSS). Objects are selected according to strict isolation criteria: IEGs must be separated by at least 2.5 Mpc from any neighboring non-dwarf companion galaxy (MV> -16.5 mag). These criteria insure that the IEGs have never interacted with another existing galaxy since formation. We have combined SDSS images in the u,g,r filters to improve the signal-to-noise ratio. The stacked images permit a more robust determination of the morphology and photometric structure of the candidate galaxies. The images are interpreted using annular surface photometry and a bulge/disk decomposition technique. Our sample defines a complete volume-limited population of extremely isolated early-type galaxies within a distance of 72Mpc.

  4. Isolation of total RNA from pollens.

    Science.gov (United States)

    Bijli, K M; Singh, B P; Sridhara, S; Arora, N

    2001-05-01

    Isolation of total RNA from plant materials has been difficult, due to the presence of complex organic substances and the associated pigmentation. In fact, there is a dearth of standardized protocols for isolating total RNA from pollens. To find a simple and reliable method for isolating total RNA from pollen, four methods, viz. phenol/SDS (PS), guanidine HCl (GH), tri-reagent (TR), and modified SDS-betaME (SB) were tested with fresh pollen of Ricinus communis (procured at -70 degrees C) and pollen dried at 30-37 degrees C. The quality and quantity of RNA was superior for the material processed at -70 degrees C. SB gave the highest RNA yield (2.35 mg/g, OD260/280 >2.0), compared to other methods. The results obtained by the SB method were found to be comparable with the widely used tri-reagent method. This was validated with other pollens of Imperata cylindrica and Xanthium strumarium. The yield obtained from graded amounts of pollen was consistent with SB, compared to the TR method. The RNA isolated by SB gave good quality mRNA for synthesizing cDNA. The SDS-betaME method is simple, efficient, and uses less expensive reagents. Hence, we recommend the modified SDS-betaME method for isolating total RNA from pollens. PMID:11426703

  5. Reinforcement of gametic isolation in Drosophila.

    Directory of Open Access Journals (Sweden)

    Daniel R Matute

    2010-03-01

    Full Text Available Reinforcement, a process by which natural selection increases reproductive isolation between populations, has been suggested to be an important force in the formation of new species. However, all existing cases of reinforcement involve an increase in mate discrimination between species. Here, I report the first case of reinforcement of postmating prezygotic isolation (i.e., barriers that act after mating but before fertilization in animals. On the slopes of the African island of São Tomé, Drosophila yakuba and its endemic sister species D. santomea hybridize within a well-demarcated hybrid zone. I find that D. yakuba females from within this zone, but not from outside it, show an increase in gametic isolation from males of D. santomea, an apparent result of natural selection acting to reduce maladaptive hybridization between species. To determine whether such a barrier could evolve under laboratory conditions, I exposed D. yakuba lines derived from allopatric populations to experimental sympatry with D. santomea, and found that both behavioral and gametic isolation become stronger after only four generations. Reinforcement thus appears to be the best explanation for the heightened gametic isolation seen in sympatry. This appears to be the first example in animals in which natural selection has promoted the evolution of stronger interspecific genetic barriers that act after mating but before fertilization. This suggests that many other genetic barriers between species have been increased by natural selection but have been overlooked because they are difficult to study.

  6. An active viscoelastic metamaterial for isolation applications

    Science.gov (United States)

    Reynolds, M.; Daley, S.

    2014-04-01

    Metamaterials are of interest due to their ability to produce novel acoustic behaviour beyond that seen in naturally occurring media. Of particular interest is the appearance of band gaps which lead to very high levels of attenuation within narrow frequency ranges. Resonant elements within metamaterials allow band gaps to form within the long wavelength limit at low frequencies where traditional passive isolation solutions suffer poor performance. Hence metamaterials may provide a path to high performance, low frequency isolation. Two metamaterials are presented here. An acoustic material consisting of an array of split hollow spheres is developed, and its performance is validated experimentally. The application of an acoustic/mechanical analogy allows the development of an elastodynamic metamaterial that could be employed as a high performance vibration isolator at low frequencies. A prototype isolator is manufactured, and its performance is measured. The passively occurring band gap is enhanced using an active control architecture. The use of the active control system in conjunction with the natural passive behaviour of the metamaterial enables high levels of isolation across a broad frequency range. An eventual goal of the work is to produce such materials on a small scale, and as such the metamaterials developed are designed for, and produced using, additive layer manufacturing techniques.

  7. Diabetes in Population Isolates: Lessons from Greenland.

    Science.gov (United States)

    Grarup, Niels; Moltke, Ida; Albrechtsen, Anders; Hansen, Torben

    2015-01-01

    Type 2 diabetes (T2D) is an increasing health problem worldwide with particularly high occurrence in specific subpopulations and ancestry groups. The high prevalence of T2D is caused both by changes in lifestyle and genetic predisposition. A large number of studies have sought to identify the genetic determinants of T2D in large, open populations such as Europeans and Asians. However, studies of T2D in population isolates are gaining attention as they provide several advantages over open populations in genetic disease studies, including increased linkage disequilibrium, homogeneous environmental exposure, and increased allele frequency. We recently performed a study in the small, historically isolated Greenlandic population, in which the prevalence of T2D has increased to more than 10%. In this study, we identified a common nonsense variant in TBC1D4, which has a population-wide impact on glucose-stimulated plasma glucose, serum insulin levels, and T2D. The variant defines a specific subtype of non-autoimmune diabetes characterized by decreased post-prandial glucose uptake and muscular insulin resistance. These and other recent findings in population isolates illustrate the value of performing medical genetic studies in genetically isolated populations. In this review, we describe some of the advantages of performing genetic studies of T2D and related cardio-metabolic traits in a population isolate like the Greenlandic, and we discuss potentials and perspectives for future research into T2D in this population. PMID:27111118

  8. Applicability of base isolation made of elastomeric isolators for the protection of cultural heritage

    Directory of Open Access Journals (Sweden)

    Vojko Kilar

    2009-01-01

    Full Text Available This article briefly presents the applicability of base isolation made of elastomeric isolators for the protection of heritage architecture. The first part of the article gives an illustrative overview on the use of base isolation throughout the world, together with an analysis of guidelines for the protection and management of places of heritage architecture. The guidelines which are given through international agreements and resolutions on the conservation of monuments have to be considered when designing the base isolation of existing monuments. Generally, interventions into such structures should be minimal or visible as little as possible and should minimally affect the aesthetics and functionality of the object. In the second part of the article the general and some special requirements for base isolation design with elastomeric isolators are presented. The influence of the slenderness of the structure is analysed in more detail. The analysis is based on the corresponding rocking prevention criterion, upon the condition that the isolators cannot bear any tensile forces. The article concludes with a presentation of the maximum height-to-width ratios for objects that can be mounted on isolators, fulfilling the given rocking prevention criterion for different soil conditions. The maximum aspect ratios have also been determined by considering 5 appropriately scaled ground motions from the 1998 Posočje earthquake.

  9. Draft Genome Sequences of Five Yersinia pseudotuberculosis ST19 Isolates and One Isolate Variant.

    Science.gov (United States)

    Platonov, Mikhail E; Blouin, Yann; Evseeva, Vera V; Afanas'ev, Maxim V; Pourcel, Christine; Balakhonov, Sergey V; Vergnaud, Gilles; Anisimov, Andrey P

    2013-04-11

    We report the first draft genome sequences of five Yersinia pseudotuberculosis isolates of sequence type (ST) 19 and of a variant from one of the five isolates. The total length of assemblies ranged from 4,226,485 bp to 4,274,148 bp, including between 3,808 and 3,843 predicted coding sequences.

  10. Molecular characterisation of clinical and environmental isolates of Mycobacterium kansasii isolates from South African gold mines.

    Science.gov (United States)

    Kwenda, Geoffrey; Churchyard, Gavin J; Thorrold, Catherine; Heron, Ian; Stevenson, Karen; Duse, Adriano G; Marais, Elsé

    2015-03-01

    Mycobacterium kansasii (M. kansasii) is a major cause of non-tuberculous mycobacterial pulmonary disease in the South African gold-mining workforce, but the source of infection and molecular epidemiology are unknown. This study investigated the presence of M. kansasii in gold and coal mine and associated hostel water supplies and compared the genetic diversity of clinical and environmental isolates of M. kansasii. Five M. kansasii and ten other potentially pathogenic mycobacteria were cultured mainly from showerhead biofilms. Polymerase chain reaction-restriction analysis of the hsp65 gene on 196 clinical and environmental M. kansasii isolates revealed 160 subtype I, eight subtype II and six subtype IV strains. Twenty-two isolates did not show the typical M. kansasii restriction patterns, suggesting that these isolates may represent new subtypes of M. kansasii. In contrast to the clonal population structure found amongst the subtype I isolates from studies in other countries, DNA fingerprinting of 114 clinical and three environmental subtype I isolates demonstrated genetic diversity amongst the isolates. This study demonstrated that showerheads are possible sources of M. kansasii and other pathogenic non-tuberculous mycobacterial infection in a gold-mining region, that subtype I is the major clinical isolate of M. kansasii strain and that this subtype exhibits genetic diversity. PMID:25719478

  11. Identity of streptococcal blood isolates and oral isolates from two patients with infective endocarditis

    DEFF Research Database (Denmark)

    Fiehn, N E; Gutschik, E; Larsen, Tove;

    1995-01-01

    The purpose of this study was to isolate streptococcal strains from the oral cavities of streptococcal endocarditis patients and compare these strains biochemically and genetically with the corresponding streptococcal blood isolates. Total identity was observed between the blood and oral cavity...

  12. Escaping Deleterious Immune Response in Their Hosts: Lessons from Trypanosomatids

    Science.gov (United States)

    Geiger, Anne; Bossard, Géraldine; Sereno, Denis; Pissarra, Joana; Lemesre, Jean-Loup; Vincendeau, Philippe; Holzmuller, Philippe

    2016-01-01

    The Trypanosomatidae family includes the genera Trypanosoma and Leishmania, protozoan parasites displaying complex digenetic life cycles requiring a vertebrate host and an insect vector. Trypanosoma brucei gambiense, Trypanosoma cruzi, and Leishmania spp. are important human pathogens causing human African trypanosomiasis (HAT or sleeping sickness), Chagas’ disease, and various clinical forms of Leishmaniasis, respectively. They are transmitted to humans by tsetse flies, triatomine bugs, or sandflies, and affect millions of people worldwide. In humans, extracellular African trypanosomes (T. brucei) evade the hosts’ immune defenses, allowing their transmission to the next host, via the tsetse vector. By contrast, T. cruzi and Leishmania sp. have developed a complex intracellular lifestyle, also preventing several mechanisms to circumvent the host’s immune response. This review seeks to set out the immune evasion strategies developed by the different trypanosomatids resulting from parasite–host interactions and will focus on: clinical and epidemiological importance of diseases; life cycles: parasites–hosts–vectors; innate immunity: key steps for trypanosomatids in invading hosts; deregulation of antigen-presenting cells; disruption of efficient specific immunity; and the immune responses used for parasite proliferation. PMID:27303406

  13. Escaping deleterious immune response in their hosts: lessons from trypanosomatids

    Directory of Open Access Journals (Sweden)

    Anne eGeiger

    2016-05-01

    Full Text Available The Trypanosomatidae family includes the genera Trypanosoma and Leishmania, protozoan parasites displaying complex digenetic life cycles requiring a vertebrate host and an insect vector. Trypanosoma brucei gambiense, T. cruzi and Leishmania spp are important human pathogens causing Human African Trypanosomiasis (HAT or Sleeping Sickness, Chagas’ disease, and various clinical forms of Leishmaniasis, respectively. They are transmitted to humans by tsetse flies, triatomine bugs or sandflies and affect millions of people worldwide.In humans, extracellular African trypanosomes (T. brucei evade the hosts’ immune defences, allowing their transmission to the next host, via the tsetse vector. By contrast, T. cruzi and Leishmania sp. have developed a complex intracellular lifestyle, also preventing several mechanisms to circumvent the host’s immune response.This review seeks to set out the immune evasion strategies developed by the different trypanosomatids resulting from parasite-host interactions and, will focus on: clinical and epidemiological importance of diseases; life cycles: parasites-hosts-vectors; innate immunity: key steps for trypanosomatids in invading hosts; deregulation of antigen presenting cells; disruption of efficient specific immunity; and the immune responses used for parasite proliferation.

  14. Isolation between three antennas at 700 MHz

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Svendsen, Simon; Pedersen, Gert F.

    2015-01-01

    To address the antenna design challenges posed by many frequency bands, introduced with long-term evolution deployment, this study proposes the use of separate transmit (Tx) and receive (Rx) narrow-band antennas. In addition, a diversity Rx (Dx) antenna is needed for multiple-input multiple......-output performance. Although the isolation between two antennas at low frequencies (700 MHz) is crucial for the successful implementation of 4G in handheld terminals, it becomes more challenging when considering isolation among three antennas (one Tx and two Rx antennas) at low frequencies. Hence, a method...... that improves the isolation between the ports of one Tx and two Rx antennas is presented here. Publishe...

  15. MICROSCOPIC FUNGI ISOLATED FROM POLISH HONEY

    Directory of Open Access Journals (Sweden)

    Soňa Felšöciová

    2012-12-01

    Full Text Available The characterization of some honey samples from Poland was carried out on the basis of their microbiological (fungi and yeasts analysis. Most of the samples contained less than 20 % water. The amount of fungi found in the honey samples was less than 1 x 102 CFU.g-1 but 19 % of the samples had more yeasts than 1 x 102 CFU.g-1 – up to 5.7 x 102 CFU.g-1. The isolated fungi were Alternaria spp., Aspergillus spp., Cladosporium spp., Fusarium spp., Mycelia sterilia, Rhizopus spp. and Penicillium spp. The last genus was isolated very frequently. A total number of eight fungal Penicillium species were identified namely, Penicillium brevicompactum, P. commune, P. corylophilum, P. crustosum, P. expansum, P. griseofulvum, P. chrysogenum and P. polonicum. They were isolated using dilution plate method. The results showed that honeys produced in this region are of good microbiological quality.

  16. Characterization of lactococci isolated from homemade kefir

    Directory of Open Access Journals (Sweden)

    Kojić M.

    2007-01-01

    Full Text Available Five bacteriocin-producing lactococci isolates from traditionally prepared kefir were determined as Lactococcus lactis subsp. lactis. The analyzed isolates showed different plasmid profiles and no cross inhibition between them was detected. Moreover, natural isolate BGKF26 was resistant to the antimicrobial activity of nisin producing strain NP45. Plasmid curing experiments revealed that the genes encoding bacteriocin and proteinase production are located on separate genetic elements, except in BGKF26. Production of the tested bacteriocins depends on the concentration of casitone or triptone in the medium. Higher concentrations of casitone or triptone induce bacteriocin activity. Our DNA-DNA hybridization analyses suggest that the analyzed antimicrobial compounds probably are lactococcin-like bacteriocins.

  17. Approaches to counter loneliness and social isolation.

    Science.gov (United States)

    Price, Bob

    2015-09-01

    Social isolation and loneliness are significant threats for older people and may be associated with mental and physical health problems. This article revisits what is meant by social isolation and loneliness and explores the way in which social change can trigger both problems. Social networks are discussed as the means by which older people can mediate the stresses of change around them. The article summarises some of the health consequences of loneliness, indicates some simple measures nurses can use to limit the risk of institutional loneliness and then examines how collaborative community ventures, mentoring and befriending schemes can help older people to access and rebuild social networks that may assist them to sustain wellbeing. Case study material is used to highlight contrasting profiles of older people who may be either more or less at risk of social isolation.

  18. Negative-stiffness-mechanism vibration isolation systems

    Science.gov (United States)

    Platus, David L.

    1992-02-01

    A new type of vibration isolation system offers significant improvement in performance compared with current state-of-the-art systems. The system uses negative-stiffness mechanisms to cancel the stiffness of a spring suspension. Reduction in stiffness magnifies the damping inherent in the system creating a practical means for achieving high hysteretic damping. The result is a simple, compact 6-DOF passive isolation system capable of system resonant frequencies below 0.2 Hz and first isolator resonances above 100 Hz. Resonant transmissibilities below 1.4 can be achieved with transmissibilities at the higher frequencies close to that of the ideal undamped system. The negative-stiffness mechanisms can cancel the stiffness of power cables, hoses or other lines connected to payloads. This paper develops the theory, describes typical configurations and summarizes test data with prototype systems.

  19. Dual isolation technique for paediatric lung surgery.

    Directory of Open Access Journals (Sweden)

    Pantvaidya S

    1994-04-01

    Full Text Available This report describes a dual isolation technique adopted to isolate the lungs from one another at the time of right pneumonectomy in a child (age: 5 yrs, 10 kg weight with evidence of infective lung disease associated with copious purulent secretion and compromised respiratory function. The isolation of right lung from left was achieved by placing Fogarty embolectomy catheter in right main bronchus and a plain polyvinylchloride endotracheal tube (which was aseptically preshaped to have a distal 45 degrees angulation towards left in left main bronchus. No soiling of left lung occurred during surgery and patient remained hemodynamically stable. In the same child, post-thoracotomy pain was relieved for five days with buprenorphine, administered through a lumbar epidural catheter. The child had an uneventful post-operative course and cooperated for physiotherapy.

  20. Weakly isolated horizon information loss paradox

    CERN Document Server

    Chen, Ge-Rui

    2014-01-01

    In this paper we investigate the information loss paradox of weakly isolated horizon(WIH) based on the Parikh and Wilczek's tunneling spectrum. We find that there are correlations among Hawking radiations from weakly isolated horizon, the information can be carried out in terms of correlations between sequential emissions, and the radiation is an entropy conservation process. We generalize Refs.[11-13]' results to a more general spacetime. Through revisiting the calculation of tunneling of weakly isolated horizon, we find that Ref.[12]'s requirement that radiating particles have the same angular momenta of unit mass as that of black hole is not needed, and the energy and angular momenta of emitting particles are very arbitrary, which should be restricted only by keeping the cosmic censorship of black hole.

  1. RNA isolation and fractionation with compaction agents

    Science.gov (United States)

    Murphy, J. C.; Fox, G. E.; Willson, R. C.

    2001-01-01

    A new approach to the isolation of RNA from bacterial lysates employs selective precipitation by compaction agents, such as hexammine cobalt and spermidine. Using 3.5 mM hexammine cobalt, total RNA can be selectively precipitated from a cell lysate. At a concentration of 2 mM hexammine cobalt, rRNA can be fractionated from low molecular weight RNA. The resulting RNA mixture is readily resolved to pure 5S and mixed 16S/23S rRNA by nondenaturing anion-exchange chromatography. Using a second stage of precipitation at 8 mM hexammine cobalt, the low molecular weight RNA fraction can be isolated by precipitation. Compaction precipitation was also applied to the purification of an artificial stable RNA derived from Escherichia coli 5S rRNA and to the isolation of an Escherichia coli-expressed ribozyme. Copyright 2001 Academic Press.

  2. Isolates of Staphylococcus aureus and saprophyticus resistant to antimicrobials isolated from the Lebanese aquatic environment.

    Science.gov (United States)

    Harakeh, Steve; Yassine, Hadi; Hajjar, Shady; El-Fadel, Mutasem

    2006-08-01

    The indiscriminate use of antimicrobials especially in developing countries has evoked serious bacterial resistance and led to the emergence of new and highly resistant strains of bacteria to commonly used antimicrobials. In Lebanon, pollution levels and bacterial infections are increasing at a high rate as a result of inadequate control measures to limit untreated effluent discharges into the sea or freshwater resources. The aim of this study was to isolate and molecularly characterize various Staphylococcus strains isolated from sea water, fresh water, sediments, and crab samples collected from representative communities along the coast of Lebanon. The results on the antimicrobial resistance indicated that the level of resistance of Staphylococcus aureus varied with various antimicrobials tested. The resistance patterns ranged between 45% in freshwater isolates and 54.8% in seawater ones. Fifty one percent of the tested isolates have shown resistance to at least one of the five tested antimicrobials; with seawater isolates exhibiting the highest rates of antimicrobial resistance.

  3. 33 CFR 62.29 - Isolated danger marks.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Isolated danger marks. 62.29... NAVIGATION UNITED STATES AIDS TO NAVIGATION SYSTEM The U.S. Aids to Navigation System § 62.29 Isolated danger marks. Isolated danger marks indicate an isolated danger which may be passed on all sides. As...

  4. Isolation of Mycoplasma hyosynoviae from pneumonic lung of swine.

    Science.gov (United States)

    Dahlia, H; Tan, L J; Zarrahimah, Z; Maria, J

    2009-12-01

    The isolation of Mycoplasma hyosynoviae from a piglet with severe pneumonia is described. This is the first report of M. hyosynoviae isolation in the country. The lung sample where the isolation was made was severely consolidated, suppurative and pleurisy. The pathogenicity of the M. hyosynoviae isolated has yet to be determined. PMID:20237449

  5. Sleep-isolated Trichotillomania (SITTM): A Case Report

    Science.gov (United States)

    Goyal, Dharmendra; Surya, Sandarsh; Elder, Joshua; Mccall, William V.; Graham, Krystle

    2016-01-01

    We report a case of sleep-isolated trichotillomania admitted to the hospital for alcohol detoxification. It would be helpful for patients with sleep-isolated trichotillomania to have diagnostic polysomnography to identify any other sleep-related pathology and correlate sleep-isolated trichotillomania behaviors with the sleep cycle to identify specific treatment for sleep-isolated trichotillomania.

  6. Numerical Modelling of Rubber Vibration Isolators: identification of material parameters

    NARCIS (Netherlands)

    Beijers, Clemens; Noordman, Bram; Boer, de André

    2004-01-01

    Rubber vibration isolators are used for vibration isolation of engines at high frequencies. To make a good prediction regarding the characteristics of a vibration isolator in the design process, numerical models can be used. However, for a reliable prediction of the dynamic behavior of the isolator,

  7. Assesing Geographic Isolation of the Galapagos Islands

    Science.gov (United States)

    Orellana, D.; Smith, F.

    2016-06-01

    The Galapagos Archipelago is one of the most important ecological spots in the planet due its unique biodiversity, active geology, and relatively well-preserved ecosystems. These characteristics are strongly based on the geographical isolation of the islands. On the one hand this isolation allowed the evolution processes that gave the islands their international fame and on the other hand it kept them from major human impacts that affected the vast majority of the Earth's surface. Galapagos' geographical isolation is therefore of mayor value, but it is rapidly diminishing due to the increase of marine and air transportation among islands and with the rest of the world. This increased accessibility implies enhanced risks for the ecological dynamics on the archipelago (e.g. increased risk of biological invasions, uncontrolled tourism growth, more water and energy consumption). Here, we introduce a general accessibility model to assess geographical isolation of the Galapagos Islands. The model aims to characterize accessibility in terms of human mobility by evaluating travel time to each point of the archipelago using all available transportation modalities. Using a multi criteria cost surface for marine and land areas, we estimated travel time for each surface unit using the fastest route and mode of transportation available while considering several friction factors such as surface type, slope, infrastructure, transfer points, legal restrictions, and physical barriers. We created maps to evaluate the isolation of different islands and places, highlighting the potential risks for several habitats and ecosystems. The model can be used for research and decision-making regarding island conservation, such as estimating spreading paths for invasive species, informing decisions on tourism management, and monitoring isolation changes of sensitive ecosystems.

  8. Isolated Fetal Ascite Associated with Cardiac Diseases

    Directory of Open Access Journals (Sweden)

    Vehbi Doğan

    2014-12-01

    Full Text Available Fetal ascite is defined as fluid accumulation in peritoneal cavity. It can be seen as isolated disease or an early sign of hydrops fetalis. Once fetal ascite is detected, a careful examination for hydops fetalis and possible underlying disease is necessary, since its prognosis and treatment depends mostly on the cause. Non-immunologic fetal ascite is an uncommon problem occurring for many reasons, such as urinary tract obstruction, congenital infections, genetic and metabolic diseases, gastrointestinal diseases and cardiovascular diseases. Here in this report we present two isolated fetal ascite that occurred secondary to cardiac diseases.

  9. Function analysis of steam isolation valves

    International Nuclear Information System (INIS)

    Function analysis of system-medium-operated steam isolation valves has been the objective of the Swedish-Finnish IVLS project, the results of which are presented in this report. Theoretical models were to be verified against available experimental data, to some extent from the HDR blowdown experiments, which are part of a German reactor safety program. Finnish hydraulic measurements on a valve model (scale 1:2.15) have been performed to give complementary data. The analysis work has covered the thermal-hydraulic behaviour of steam isolation valves as well as phenomena related to structural mechanics. Work performed under contract with the Swedish Nuclear Power Inspectorate. (Author)

  10. Doubts and Concerns about Isolated Maternal Hypothyroxinemia

    Directory of Open Access Journals (Sweden)

    Mariacarla Moleti

    2011-01-01

    Full Text Available There is evidence that isolated maternal hypothyroxinemia may have detrimental effects on both mother and foetus. Nonetheless, this condition is still far from being universally accepted as a separate thyroid disease, and a standard definition of this state of mild thyroid underfunction is still lacking. We will review the biochemical criteria used to define isolated maternal hypothyroxinemia, together with current methodological issues related to FT4 assays. We will also discuss its epidemiological impact in both iodine-deficient and-sufficient areas, and the effectiveness of iodine prophylaxis on maternal thyroid function and neuropsychomotor development in offspring.

  11. Isolated humeral recurrence in endometrial carcinoma

    Science.gov (United States)

    Devdas, Santosh Kumar; Digumarti, Leela; Digumarti, Raghunadharao; Patro, Kunha Charan; Nutakki, Ramakoteswararao

    2016-01-01

    Isolated skeletal metastasis in endometrial carcinoma at recurrence is very rare. We report a 52-year-old woman diagnosed to have FIGO Stage 1b, Grade 1 endometrioid adenocarcinoma, presenting with isolated distal humerus metastasis, 2 years after surgery and adjuvant radiotherapy for primary disease. Imaging, bone scintigraphy, and cytology confirmed the diagnosis of poorly differentiated metastatic adenocarcinoma. She was treated with local radiotherapy followed by six cycles of paclitaxel and carboplatin chemotherapy along with zoledronic acid, monthly. She is symptom-free after the treatment and at a first follow-up visit after 3 months. PMID:27688615

  12. Spectroscopy of a weakly isolated horizon

    Science.gov (United States)

    Chen, Ge-Rui; Huang, Yong-Chang

    2016-06-01

    The spectroscopy of a weakly isolated horizon has been investigated. We obtain an equally spaced entropy spectrum with its quantum equal to the one given by Bekenstein (Phys Rev D 7:2333, 1973). We demonstrate that the quantization of entropy and area is a generic property of horizons which exists in a wide class of spacetimes admitting weakly isolated horizons. Our method based on the tunneling method also indicates that the entropy quantum of black hole horizons is closely related to Hawking temperature.

  13. Isolation of functional, coated, endocytic vesicles

    OpenAIRE

    1991-01-01

    Brief internalization of [125I]transferrin was used to label coated endocytic vesicles, which were then purified using a combination of 2H2O and 2H2O/Ficoll density gradients. Purification was monitored using an assay measuring fusion of endocytic organelles, so as to isolate functional vesicles. Isolated vesicles had all the properties of clathrin-coated vesicles, being enriched for the major components of clathrin coats and uncoated by either 1 M Tris-HCl or an uncoating ATPase. Nearly half...

  14. Isolation, Culture, and Staining of Single Myofibers

    Science.gov (United States)

    Gallot, Yann Simon; Hindi, Sajedah M.; Mann, Aman K.; Kumar, Ashok

    2016-01-01

    Adult skeletal muscle regeneration is orchestrated by a specialized population of adult stem cells called satellite cells, which are localized between the basal lamina and the plasma membrane of myofibers. The process of satellite cell-activation, proliferation, and subsequent differentiation that occurs during muscle regeneration can be recapitulated ex vivo by isolation of single myofibers from skeletal muscles and culturing them under suspension conditions. Here, we describe an improved protocol to evaluate ex vivo satellite cells activation through isolation of single myofibers from extensor digitorum longus (EDL) muscle of mice and culturing and staining of myofiber-associated satellite cells with the markers of self-renewal, proliferation, and differentiation.

  15. Lepton Isolation Using Particle Flow Objects for the ATLAS Detector

    CERN Document Server

    Moortgat, Seth

    2014-01-01

    This note presents a novel method for isolation using particle flow objects. The study is focused on muon isolation, but it is expected that these techniques would also be applicable for electrons and photons. It will be shown to be robust against pile-up, which is one of the challenges at the LHC. High efficiency in identifying truly isolated particles needs to be balanced by good fake rejection such that non-isolated particles do not pass the isolation criteria. Particle flow isolation shows improvements over previously used track and calorimeter based isolation, preserving a higher fake rejection for a similar isolation efficiency. For an efficiency of 90$\\%$, particle flow isolation achieves a fake rejection of 63$\\%$ whereas the standard isolation techniques reach only 40$\\%$.

  16. Formation, Evolution and Properties of Isolated Field Elliptical Galaxies

    CERN Document Server

    Niemi, Sami-Matias; Nurmi, Pasi; Saar, Enn

    2010-01-01

    [Abridged] We study the properties, evolution and formation mechanisms of isolated field elliptical galaxies. We create a mock catalogue of isolated field elliptical galaxies from the Millennium Simulation Galaxy Catalogue, and trace their merging histories. The formation, identity and assembly redshifts of simulated isolated and non-isolated elliptical galaxies are studied and compared. Observational and numerical data are used to compare age, mass, and the colour-magnitude relation. Our results, based on simulation data, show that almost seven per cent of all elliptical galaxies brighter than -19mag in B-band can be classified as isolated field elliptical galaxies. Isolated field elliptical galaxies show bluer colours than non-isolated elliptical galaxies and they appear younger, in a statistical sense, according to their mass weighted age. Isolated field elliptical galaxies also form and assemble at lower redshifts compared to non-isolated elliptical galaxies. About 46 per cent of isolated field elliptical...

  17. Antitrypanosomal activity of polycarpol from Piptostigma preussi (Annonaceae).

    Science.gov (United States)

    Ngantchou, Igor; Nkwengoua, Ernestine; Nganso, Yves; Nyasse, Barthelemy; Denier, Colette; Hannaert, Veronique; Schneider, Bernd

    2009-04-01

    Polycarpol, sitosterol and sitosterol-3-O-beta-D-glucoside isolated for the first time from Piptostigma preussi (Annonaceae) occur regularly in some Annonaceae such as Piptostigma genus. Polycarpol exhibits interesting antitrypanosomal activity with an ED(50) value of 5.11 microM on Trypanosoma brucei cells. Moreover, it inhibits T. brucei glycolytic enzymes GAPDH and PFK with IC(50) values of 650 and 180 microM respectively.

  18. Worldwide Abundance and Distribution of Bacillus thuringiensis Isolates

    OpenAIRE

    Martin, Phyllis A. W.; Travers, Russell S.

    1989-01-01

    We found the insect control agent Bacillus thuringiensis to be a ubiquitous soil microorganism. Using acetate selection to screen soil samples, we isolated B. thuringiensis in 785 of 1,115 soil samples. These samples were obtained in the United States and 29 other countries. A total of 48% of the B. thuringiensis isolates (8,916 isolates) fit the biochemical description of known varieties, while 52% represented undescribed B. thuringiensis types. Over 60% (1,052 isolates) of the isolates test...

  19. Virulence of Rhodococcus equi Isolated from Cats and Dogs

    OpenAIRE

    Takai, Shinji; Martens, Ronald J.; Julian, Alan; Garcia Ribeiro, Márcio; Rodrigues de Farias, Marconi; Sasaki, Yukako; Inuzuka, Kazuho; Kakuda, Tsutomu; Tsubaki, Shiro; Prescott, John F.

    2003-01-01

    Nine cat isolates and nine dog isolates of Rhodococcus equi from clinical material were investigated for the presence of the virulence-associated antigens (VapA and VapB) and virulence plasmids. Five of the cat isolates and one dog isolate were VapA positive and contained an 85-kb type I or an 87-kb type I plasmid. The remaining 12 isolates were avirulent R. equi strains and contained no virulence plasmids.

  20. Isolation of Integrated Optical Acousto-Optic Switch

    Institute of Scientific and Technical Information of China (English)

    XIAO Li-Feng; LIU Ying; WANG Wei-Peng; GENG Fan

    2006-01-01

    @@ Isolation of a new structured acousto-optic switch based on an integrated optical polarization-independent quasicollinear acousto-optic tunable filter is studied in detail. The factors that influence the isolation of the optical switch are analysed, the expressions of the isolation are educed, and the isolation of the device is measured in experiment. It is found that the isolation mainly depends on the TE/TM mode intensity ratio, the mode-splitter extinction rate, and the conversion efficiency.

  1. Comparative molecular analysis of ovine and bovine Streptococcus uberis isolates.

    Science.gov (United States)

    Gilchrist, T L; Smith, D G E; Fitzpatrick, J L; Zadoks, R N; Fontaine, M C

    2013-02-01

    Streptococcus uberis causes clinical and subclinical mastitis in cattle and sheep, but it is unknown whether the composition of Strep. uberis populations differs between host species. To address this, we characterized a collection of bovine and ovine Strep. uberis isolates with shared geographical and temporal origins by means of an expanded multilocus sequence typing scheme. Among 14 ovine and 35 bovine isolates, 35 allelic profiles were detected. Each allelic profile was associated with a single host species and all but one were new to the multilocus sequence typing database. The median number of new alleles per isolate was higher for ovine isolates than for bovine isolates. None of the ovine isolates belonged to the global clonal complexes 5 or 143, which are commonly associated with bovine mastitis and which have a wide geographical distribution. Ovine isolates also differed from bovine isolates in carriage of plasminogen activator genes, with significantly higher prevalence of pauB in ovine isolates. Isolates that were negative for yqiL, one of the targets of multilocus sequence typing, were found among ovine and bovine isolates and were not associated with a specific sequence type or global clonal complex. One bovine isolate carried a gapC allele that was probably acquired through lateral gene transfer, most likely from Streptococcus salivarius. We conclude that ovine isolates are distinct from bovine isolates of Strep. uberis, and that recombination between isolates from different host species or bacterial species could contribute to changes in virulence gene profiles with relevance for vaccine development. PMID:23200465

  2. Virulence of South African isolates of Haemophilus paragallinarum. Part 1: NAD-dependent field isolates.

    Science.gov (United States)

    Bragg, R R

    2002-06-01

    The virulence of four South African field isolates of NAD-dependent Haemophilus paragallinarum, representing the four serovars known to occur in that country, was investigated. During this study an alternative challenge model for infectious coryza was used, in which the infectivity as well the virulence of different isolates could be evaluated. The challenge model consisted of the direct challenge, via intrasinus injection of one chicken in a row of interconnected layer cages, containing 10 chickens, which are subsequently infected by natural routes. A scoring system of the clinical signs was established in which a score is given to the ability of the isolate to produce clinical signs in the challenge birds. The mean daily disease score for the flock can be calculated and plotted on a graph to give a graphic representation of the disease profile. A mean disease score, calculated over a 20-day examination period can be calculated. Isolates can then be compared to each other, either graphically or by a comparison of the mean disease scores. It has been demonstrated using this scoring system that the South African serogroup C isolates appear to be more virulent than the South African serogroup A or B isolates. It was further established that the serovar C-3 isolate appeared to be the most virulent.

  3. Cortical overgrowth in fetuses with isolated ventriculomegaly.

    Science.gov (United States)

    Kyriakopoulou, Vanessa; Vatansever, Deniz; Elkommos, Samia; Dawson, Sarah; McGuinness, Amy; Allsop, Joanna; Molnár, Zoltán; Hajnal, Joseph; Rutherford, Mary

    2014-08-01

    Mild cerebral ventricular enlargement is associated with schizophrenia, autism, epilepsy, and attention-deficit/hyperactivity disorder. Fetal ventriculomegaly is the most common central nervous system (CNS) abnormality affecting 1% of fetuses and is associated with cognitive, language, and behavioral impairments in childhood. Neurodevelopmental outcome is partially predictable by the 2-dimensional size of the ventricles in the absence of other abnormalities. We hypothesized that isolated fetal ventriculomegaly is a marker of altered brain development characterized by relative overgrowth and aimed to quantify brain growth using volumetric magnetic resonance imaging (MRI) in fetuses with isolated ventriculomegaly. Fetal brain MRI (1.5 T) was performed in 60 normal fetuses and 65 with isolated ventriculomegaly, across a gestational age range of 22-38 weeks. Volumetric analysis of the ventricles and supratentorial brain structures was performed on 3-dimensional reconstructed datasets. Fetuses with isolated ventriculomegaly had increased brain parenchyma volumes when compared with the control cohort (9.6%, P ventriculomegaly may represent the neurobiological substrate for cognitive, language, and behavioral deficits in these children.

  4. Overcoming the isolation of disadvantaged housing areas

    DEFF Research Database (Denmark)

    Stender, Marie; Bech-Danielsen, Claus

    Disadvantaged social housing areas in Denmark are currently subject to more thorough physical refurbishments, aiming to overcome the isolated character of the housing estates. The ambition is to attract new users and residents by opening up the borders of the area and establish attractive, new...

  5. Numerical modelling of rubber vibration isolators

    NARCIS (Netherlands)

    Beijers, Clemens A.J.; Boer, de André; Nilsson, A.; Boden, H.

    2003-01-01

    An important cause for interior noise in vehicles is structure-borne sound from the engine. The vibrations of the source (engine) are transmitted to the receiver structure (the vehicle) causing interior noise in the vehicle. For this reason the engine is supported by rubber isolators for passive iso

  6. Isolation of Circulating Tumor Cells by Dielectrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Gascoyne, Peter R. C., E-mail: pgascoyn@mdanderson.org [Department of Imaging Physics Research, The University of Texas M.D. Anderson Cancer Center Unit 951, 1515 Holcombe Boulevard, Houston, TX 77030 (United States); Shim, Sangjo [Department of Imaging Physics Research, The University of Texas M.D. Anderson Cancer Center Unit 951, 1515 Holcombe Boulevard, Houston, TX 77030 (United States); Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, C0800, Austin, TX 78712 (United States); Present address: Micro & Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, 208 North Wright Street, Urbana, IL 61801 (United States)

    2014-03-12

    Dielectrophoresis (DEP) is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs) from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a) the principles of DEP; (b) the biological basis for the dielectric differences between CTCs and blood cells; (c) why such differences are expected to be present for all types of tumors; and (d) instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF) is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies.

  7. Design of high Isolation benzocyclobutene microring resonator

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We report the design of benzocyclobutene microring resonator of symmetric coupling made of a readily available polymer with a higher isolation of 43.8 dB, a finesse of 34, and a Q value of 1.5 × 10s. The FDTD method predicts a drop efficiencyof almost 80% for a gap of 0.55μm.

  8. Isolated pharmacomechanical thrombolysis using the Trellis system

    LENUS (Irish Health Repository)

    O’Sullivan, GJ

    2010-01-01

    While anticoagulation remains the current gold standard for treating acute deep vein thrombosis,1 there is a growing body of evidence that rapid thrombus removal results in better short- and long-term outcomes.2–5 This is a practical guide to achieve rapid thrombus removal with isolated pharmacomechanical thrombolysis using the Trellis® peripheral infusion system.\\r\

  9. Geotrichum capitatum, a new isolate degrading phenol

    Directory of Open Access Journals (Sweden)

    Anna Grabińska-Łoniewska

    2014-08-01

    Full Text Available Geotrichum capitatum strain GID2, highly active in degradation of phenol was isolated from the biocenosis of rotating discs reactor treating petrochemical wastes. It was also able to utilize ethanol, glycerol, acetate, citrate and p-, m-cresoles as sole C-sources.

  10. Isolation of Cholesterol from an Egg Yolk

    Science.gov (United States)

    Taber, Douglass F.; Li, Rui; Anson, Cory M.

    2011-01-01

    A simple procedure for the isolation of the cholesterol, by hydrolysis and extraction followed by column chromatography, is described. The cholesterol can be further purified by complexation with oxalic acid. It can also be oxidized and conjugated to cholestenone. The source of the cholesterol is one egg yolk, which contains about 200 mg of…

  11. Decoherence in Nearly-Isolated Quantum Dots

    DEFF Research Database (Denmark)

    Folk, J.; M. Marcus, C.; Harris jr, J.

    2000-01-01

    Decoherence in nearly-isolated GaAs quantum dots is investigated using the change in average Coulomb blockade peak height upon breaking time-reversal symmetry. The normalized change in average peak height approaches the predicted universal value of 1/4 at temperatures well below the single...

  12. Active seat isolation for hybrid electric vehicles

    Science.gov (United States)

    Leo, Donald J.; Malowicki, Mark; Buckley, Stephen J.; Naganathan, Ganapathy

    1999-07-01

    A feasibility study in the use of induced strain actuators for active seal isolation is described. The focus of the work is the isolation of lightweight automotive seats for hybrid-electric vehicles. The feasibility study is based on a numerical analysis of a three-degree-of-freedom vibration model of the seat. Mass and inertia properties are based on measurements from a powered seat that is found in current model year automobiles. Tradeoffs between vertical acceleration of the seat, actuator stroke requirements, and isolation frequency are determined through numerical analysis of the vibration model. Root mean square accelerations and actuator strokes are computed using power spectral densities that model broadband excitation and road excitation that is filtered by the vehicle suspension. Numerical results using the road excitation indicate that factors of two to three reduction in vertical acceleration are achieved when the active isolation frequency is reduced to approximately 1 Hz with damping factors on the order of 10 to 30 percent critical. More significant reductions are achieved in the case of broadband floor excitation. Root mean square actuator strokes for both case are int he range of 0.4 to 50 mm. Root mean square accelerations in the vertical direction are consistent with the levels found in standard comfort curves.

  13. Rabies in Sri Lanka: Splendid Isolation

    OpenAIRE

    Nanayakkara, Susilakanthi; Smith, Jean S.; Rupprecht, Charles E.

    2003-01-01

    Rabies virus exists in dogs on Sri Lanka as a single, minimally divergent lineage only distantly related to other rabies virus lineages in Asia. Stable, geographically isolated virus populations are susceptible to local extinction. A fully implemented rabies-control campaign could make Sri Lanka the first Asian country in >30 years to become free of rabies virus.

  14. Corynebacterium macginleyi isolated from a corneal ulcer

    Directory of Open Access Journals (Sweden)

    Kathryn Ruoff

    2010-02-01

    Full Text Available We report the isolation of Corynebacterium macginleyi from the corneal ulcer culture of a patient, later enrolled in the Steroids for Corneal Ulcer Trial (SCUT. To our knowledge this is the first published report from North America of the recovery of C. macginleyi from a serious ocular infection.

  15. Geological problems in radioactive waste isolation

    Energy Technology Data Exchange (ETDEWEB)

    Witherspoon, P.A. (ed.)

    1991-01-01

    The problem of isolating radioactive wastes from the biosphere presents specialists in the fields of earth sciences with some of the most complicated problems they have ever encountered. This is especially true for high level waste (HLW) which must be isolated in the underground and away from the biosphere for thousands of years. Essentially every country that is generating electricity in nuclear power plants is faced with the problem of isolating the radioactive wastes that are produced. The general consensus is that this can be accomplished by selecting an appropriate geologic setting and carefully designing the rock repository. Much new technology is being developed to solve the problems that have been raised and there is a continuing need to publish the results of new developments for the benefit of all concerned. The 28th International Geologic Congress that was held July 9--19, 1989 in Washington, DC provided an opportunity for earth scientists to gather for detailed discussions on these problems. Workshop W3B on the subject, Geological Problems in Radioactive Waste Isolation -- A World Wide Review'' was organized by Paul A Witherspoon and Ghislain de Marsily and convened July 15--16, 1989 Reports from 19 countries have been gathered for this publication. Individual papers have been cataloged separately.

  16. REAL ROOT ISOLATION OF SPLINE FUNCTIONS

    Institute of Scientific and Technical Information of China (English)

    Renhong Wang; Jinming Wu

    2008-01-01

    In this paper,we propose an algorithm for isolating real roots of a given univariate spline function,which is based on the use of Descartes' rule of signs and de Casteljau algorithm.Numerical examples illustrate the flexibility and effectiveness of the algorithm.

  17. Molecular characterization of Danish Cryptosporidium parvum isolates

    DEFF Research Database (Denmark)

    Enemark, Heidi L.; Ahrens, Peter; Juel, Cynthia Dawn;

    2002-01-01

    The genetic polymorphism among 271 Danish Cryptosporidium isolates of human and animal origin was studied by partial amplification and sequencing of the Cryptosporidium oocyst wall protein (COWP) gene, the 18S rDNA, and a microsatellite locus.dagger Furthermore, the microsatellite locus was studied...

  18. Isolated elliptical galaxies in the local Universe

    CERN Document Server

    Lacerna, I; Avila-Reese, V; Abonza-Sane, J; del Olmo, A

    2015-01-01

    We have studied a sample of 89 very isolated elliptical galaxies at z < 0.08 and compared their properties with elliptical galaxies located in a high-density environment such as the Coma supercluster. Our aim is to probe the role of environment on the morphological transformation and quenching of elliptical galaxies as a function of mass. In addition, we elucidate about the nature of a particular set of blue and star-forming isolated ellipticals identified here. We study physical properties of ellipticals such as color, specific star formation rate, galaxy size and stellar age as a function of stellar mass and environment based on SDSS data. We analyze in more detail the blue star-forming isolated ellipticals through photometric characterization using GALFIT and infer their star formation history using STARLIGHT. Among the isolated ellipticals ~ 20% are blue, 8% are star-forming and ~ 10% are recently quenched, while among the Coma ellipticals ~ 8% are blue and just <= 1% are star-forming or recently qu...

  19. An isolated vaginal metastasis from rectal cancer

    Directory of Open Access Journals (Sweden)

    Ai Sadatomo

    2016-02-01

    Conclusion: We should keep the vagina within the field of view of pelvic MRI, which is one of the preoperative diagnostic tools for colorectal cancer. If female patients show gynecological symptoms, gynecological examination should be recommended. Isolated vaginal metastases are an indication for surgical resection, and adjuvant chemotherapy is also recommended.

  20. Shewanella strain isolated from black powder

    Energy Technology Data Exchange (ETDEWEB)

    Lutterbach, Marcia T.S.; Contador, Luciana S.; Oliveira, Ana Lucia C.; Galvao, Mariana M. [National Institute of Technology (INT), Rio de Janeiro, RJ (Brazil); Pimenta, Gutemberg S. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Black powder is a term frequently used to refer to residues formed by various types of iron sulfides mixed with contaminants eventually present in the natural gas flow. According to some researchers, the occurrence of black powder in gas pipelines, besides its chemical corrosion origin, can be directly related to the sulfate-reducing bacteria (SRB) metabolism in this environment. A black powder sample was inoculated in a Post gate E medium modified with the addition of thioglycolate. The resulting positive culture was kept in the laboratory for four years until its use. A dilution technique was then performed aiming to isolate an SRB strain. The bacterial strain isolated and identified through DNA sequencing was not an SRB but rather a Shewanella sp. Compared to the sulfate-reducing bacteria group-traditionally considered the foremost responsible for microbially-influenced corrosion (MIC) - Shewanella is a facultative anaerobe and has a versatile metabolism. Shewanella is able to reduce ferric iron and sulfite, oxidize hydrogen gas, and produce hydrogen sulfide; therefore, these bacteria can be responsible for MIC and pit formation. The isolated Shewanella was used in a corrosion experiment, and the corrosion products were characterized by X-ray diffraction, identifying iron sulfides, iron oxides, and sulfur. Our results indicate that the strain isolated, S. putrefaciens, plays a key role in corrosion problems in gas pipelines. (author)

  1. Neighborhood Racial Isolation, Disorder and Obesity

    Science.gov (United States)

    Chang, Virginia W.; Hillier, Amy E.; Mehta, Neil K.

    2009-01-01

    Recent research suggests that racial residential segregation may be detrimental to health. This study investigates the influence of neighborhood racial isolation on obesity and considers the role of neighborhood disorder as a mediator in this relationship. For the city of Philadelphia, we find that residence in a neighborhood with high black…

  2. Form-Focused Instruction: Isolated or Integrated?

    Science.gov (United States)

    Spada, Nina; Lightbown, Patsy M.

    2008-01-01

    There is increasing consensus that form-focused instruction helps learners in communicative or content-based instruction to learn features of the target language that they may not acquire without guidance. The subject of this article is the role of instruction that is provided in separate (isolated) activities or within the context of…

  3. Isolation of glycoproteins from brown algae

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel process for the isolation of unique anti-oxidative glycoproteins from the pH precipitated fractions of enzymatic extracts of brown algae. Two brown seaweeds viz, Fucus serratus and Fucus vesiculosus were hydrolysed by using 3 enzymes viz, Alcalase, Viscozyme...

  4. Probiotic features of two oral Lactobacillus isolates

    Directory of Open Access Journals (Sweden)

    Gordana Zavisic

    2012-03-01

    Full Text Available In this study, we checked lactobacilli strains of human origin for their potential as probiotic. Samples were collected from oral mucosa of 16 healthy individuals, out of which twenty isolates were obtained and two of them were selected and identified as Lactobacillus plantarum (G1 and L. casei (G3. Both isolates exhibited antagonistic action towards pathogenic microorganisms such as Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella abony, and Clostridium sporogenes, but not on the growth of Candida albicans. The bacteriocin activity against Staphylococcus aureus ATCC 6358-P was shown only by L. plantarum G1. Moreover, the isolates G1 and G3 showed good viability in the acid gastric environment and in the gut environment containing bovine bile salts. The viability of G1 and G3 isolates in the gastrointestinal tract, and the adhesion to the intestinal mucosa were also confirmed in vivo. The biochemical tests of blood samples revealed lower levels of serum triglycerides and cholesterol, as well as reduced activity of alkaline phosphatase in all lactobacilli-treated Wistar rats, compared to control ones. No toxicity for NMRI Ham mice was observed. According to our experimental results, these findings imply that L. plantarum G1 and L. casei G3 could be characterized as potential probiotics.

  5. Isolation of deoxyribonucleic acids (A Review)

    International Nuclear Information System (INIS)

    The criteria of choice in this Review have been to gather some of the last advances in the methodology of DNAs isolation; also the description of the generally accepted procedures has been emphasized. Only papers published before March 1974 are reviewed, because this work has been finished during this month. (Author) 109 refs

  6. Isolated microalbuminuria indicates a poor medical prognosis

    NARCIS (Netherlands)

    Scheven, Lieneke; Van der Velde, Marije; Heerspink, Hiddo J. Lambers; De Jong, Paul E.; Gansevoort, Ron T.

    2013-01-01

    Background. Microalbuminuria is often regarded as a sign of end-organ damage due to diabetes and/or hypertension, and as such to be associated with an increased risk for cardiovascular events. It has been questioned whether isolated microalbuminuria, that is microalbuminuria in the absence of a card

  7. Water splitting: Taking cobalt in isolation

    Science.gov (United States)

    Wang, Aiqin; Zhang, Tao

    2016-01-01

    The sustainable production of hydrogen is key to the delivery of clean energy in a hydrogen economy; however, lower-cost alternatives to platinum electrocatalysts are needed. Now, isolated, earth-abundant cobalt atoms dispersed over nitrogen-doped graphene are shown to efficiently electrolyse water to generate hydrogen.

  8. CHOROIDAL TUBERCLES IN ISOLATED TUBERCULOUS MENINGITIS

    Directory of Open Access Journals (Sweden)

    Tharun Tom

    2016-04-01

    Full Text Available Choroidal tubercles are the most common manifestation of intraocular tuberculosis and results from the haematogenous spread of mycobacteria in miliary tuberculosis. However, its presence without the evidence of miliary tuberculosis is a rare entity. We present a case of isolated tuberculous meningitis with choroidal tubercles, who had no features of miliary tuberculosis.

  9. Isolated and syndromic forms of congenital anosmia

    DEFF Research Database (Denmark)

    Karstensen, H G; Tommerup, N

    2012-01-01

    Loss of smell (anosmia) is common in the general population and the frequency increases with age. A much smaller group have no memory of ever being able to smell and are classified as having isolated congenital anosmia (ICA). Families are rare, and tend to present in a dominant inheritance pattern...

  10. Geological problems in radioactive waste isolation

    International Nuclear Information System (INIS)

    The problem of isolating radioactive wastes from the biosphere presents specialists in the fields of earth sciences with some of the most complicated problems they have ever encountered. This is especially true for high level waste (HLW) which must be isolated in the underground and away from the biosphere for thousands of years. Essentially every country that is generating electricity in nuclear power plants is faced with the problem of isolating the radioactive wastes that are produced. The general consensus is that this can be accomplished by selecting an appropriate geologic setting and carefully designing the rock repository. Much new technology is being developed to solve the problems that have been raised and there is a continuing need to publish the results of new developments for the benefit of all concerned. The 28th International Geologic Congress that was held July 9--19, 1989 in Washington, DC provided an opportunity for earth scientists to gather for detailed discussions on these problems. Workshop W3B on the subject, ''Geological Problems in Radioactive Waste Isolation -- A World Wide Review'' was organized by Paul A Witherspoon and Ghislain de Marsily and convened July 15--16, 1989 Reports from 19 countries have been gathered for this publication. Individual papers have been cataloged separately

  11. Isolation and cultivation of Walsby's square archaeon

    NARCIS (Netherlands)

    Bolhuis, H; Poele, EMT; Rodriguez-Valera, F

    2004-01-01

    In 1980, A. E. Walsby described a square halophilic archaeon. This archaeon is of specific interest because of its unique shape and its abundance in hypersaline ecosystems, which suggests an important ecophysiological role. Ever since its discovery, the isolation and cultivation of 'Walsby's square

  12. Electrically conductive fibers thermally isolate temperature sensor

    Science.gov (United States)

    De Waard, R.; Norton, B.

    1966-01-01

    Mounting assembly provides thermal isolation and an electrical path for an unbacked thermal sensor. The sensor is suspended in the center of a plastic mounting ring from four plastic fibers, two of which are coated with an electrically conductive material and connected to electrically conductive coatings on the ring.

  13. Isolation of Circulating Tumor Cells by Dielectrophoresis

    Directory of Open Access Journals (Sweden)

    Peter R. C. Gascoyne

    2014-03-01

    Full Text Available Dielectrophoresis (DEP is an electrokinetic method that allows intrinsic dielectric properties of suspended cells to be exploited for discrimination and separation. It has emerged as a promising method for isolating circulation tumor cells (CTCs from blood. DEP-isolation of CTCs is independent of cell surface markers. Furthermore, isolated CTCs are viable and can be maintained in culture, suggesting that DEP methods should be more generally applicable than antibody-based approaches. The aim of this article is to review and synthesize for both oncologists and biomedical engineers interested in CTC isolation the pertinent characteristics of DEP and CTCs. The aim is to promote an understanding of the factors involved in realizing DEP-based instruments having both sufficient discrimination and throughput to allow routine analysis of CTCs in clinical practice. The article brings together: (a the principles of DEP; (b the biological basis for the dielectric differences between CTCs and blood cells; (c why such differences are expected to be present for all types of tumors; and (d instrumentation requirements to process 10 mL blood specimens in less than 1 h to enable routine clinical analysis. The force equilibrium method of dielectrophoretic field-flow fractionation (DEP-FFF is shown to offer higher discrimination and throughput than earlier DEP trapping methods and to be applicable to clinical studies.

  14. Snapshot isolation for Neo4j

    OpenAIRE

    Patiño Martínez, Marta; Sancho, Diego; Jiménez Peris, Ricardo; Brondino, Ivan; Vianello, Valerio; Dhamane, Rohit

    2016-01-01

    NoSQL data stores are becoming more and more popular. Graph databases are one of this kind of data stores. In this paper we present an overview of the implementation of snapshot isolation for Neo4j, a very popular graph database.

  15. Site identification presentation: Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    The final step in the site identification process for the Basalt Waste Isolation Project is described. The candidate sites are identified. The site identification methodology is presented. The general objectives which must be met in selecting the final site are listed. Considerations used in the screening process are also listed. Summary tables of the guidelines used are included

  16. Campylobacter iguaniorum sp. nov., isolated from reptiles

    Science.gov (United States)

    During samplings of reptiles for Epsilonproteobacteria, Campylobacter strains were isolated from lizards and chelonians not belonging to any of the established taxa. Initial AFLP, PCR, and 16S rRNA sequence analysis showed that these strains were most closely related to Campylobacter fetus and Campy...

  17. New secondary metabolites isolated from dondonae viscosa

    Science.gov (United States)

    Bioassay guided fractionation and chemical investigation of the ethanolic extract of the aerial parts of Dodonaea viscosa Linn. from Egypt, resulted in the isolation and identification of three new compounds, including two new clerodane diterpenoids and a new myo-inositol derivative, along with nine...

  18. Isolated systems with wind power. Main report

    Energy Technology Data Exchange (ETDEWEB)

    Lundsager, P.; Bindner, H.; Clausen, N.E.; Frandsen, S.; Hansen, L.H.; Hansen, J.C.

    2001-06-01

    The overall objective of this research project is to study the development of methods and guidelines rather than 'universal solutions' for the use of wind energy in isolated communities. The main specific objective of the project is to develop and present a more unified and generally applicable approach for assessing the technical and economical feasibility of isolated power supply systems with wind energy. As a part of the project the following tasks were carried out: Review of literature, field measurements in Egypt, development of an inventory of small isolated systems, overview of end-user demands, analysis of findings and development of proposed guidelines. The project is reported in one main report and four topical reports, all of them issued as Risoe reports. This is the Main Report Risoe-R-1256, summing up the activities and findings of the project and outlining an Implementation Strategy for Isolated Systems with Wind Power, applicable for international organisations such as donor agencies and development banks. (au)

  19. Natural proteins: Sources, isolation, characterization and applications

    Directory of Open Access Journals (Sweden)

    Jitendra Y Nehete

    2013-01-01

    Full Text Available Worldwide, plant protein contributes substantially as a food resource because it contains essential amino acids for meeting human physiological requirements. However, many versatile plant proteins are used as medicinal agents as they are produced by using molecular tools of biotechnology. Proteins can be obtained from plants, animals and microorganism cells. The abundant economical proteins can be obtained from plant seeds. These natural proteins are obtained by isolation procedures depending on the physicochemical properties of proteins. Isolation and purification of single protein from cells containing mixtures of unrelated proteins is achievable due to the physical and chemical attributes of proteins. The following characteristics are unique to each protein: Amino acid composition, sequence, subunit structures, size, shape, net charge, isoelectric point, solubility, heat stability and hydrophobicity. Based on these properties, various methods of isolation exist, like salting out and isoionic precipitation. Purification of proteins is quiet challenging and, therefore, several approaches like sodium dodecyl sulfate gel electrophoresis and chromatography are available. Characterization of proteins can be performed by mass spectrometry/liquid chromatography-mass spectrometry (LC-MS. The amino acid sequence of a protein can be detected by using tandem mass spectrometry. In this article, a review has been made on the sources, isolation, purification and characterization of natural proteins.

  20. Isolation and cultivation of Lyme disease spirochetes.

    OpenAIRE

    Barbour, A G

    1984-01-01

    The successful isolation and cultivation of Lyme disease spirochetes traces its lineage to early attempts at cultivating relapsing fever borreliae. Observations on the growth of Lyme disease spirochetes under different in vitro conditions may yield important clues to both the metabolic characteristics of these newly discovered organisms and the pathogenesis of Lyme disease. Images FIG. 1