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Sample records for brucei gambiense isolates

  1. Mechanism of Trypanosoma brucei gambiense resistance to human serum

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    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 in...

  2. 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

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

    Science.gov (United States)

    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

  4. 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

  5. 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.

  6. 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% (...

  7. 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

  8. 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.

  9. 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

  10. Diagnosis of human trypanosomiasis, due to Trypanosoma brucei gambiense in central Africa, by the polymerase chain reaction

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    Penchenier, Laurent; Simo, G.; Grébaut, Pascal; Nkinin, S.; Laveissière, Claude; Herder, Stéphane

    2000-01-01

    During a mass screening of sleeping sickness conducted in 1998 and 1999, and involving 27,932 persons in Cameroon and the Central African Republic, we tested the polymerase chain reaction (PCR) on whole blood for the diagnosis of human African trypanosomiasis due to #Trypanosoma brucei gambiense$. The 1858 samples obtained were from 4 groups : 155 infected patients, 1432 serological suspects detected by the card agglutination test for trypanosomiasis (CATT), 222 negative controls living in th...

  11. Familial aggregation of Trypanosoma brucei gambiense trypanosomiasis in a very high incidence community in Zaire.

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    Khonde, N; Pépin, J; Niyonsenga, T; De Wals, P

    1997-01-01

    Familial aggregation of Trypanosoma brucei gambiense human African trypanosomiasis (HAT) was investigated in 3 adjacent villages of central Zaire where 318/1431 inhabitants had previously suffered from HAT. Neither spatial nor familial aggregation was detected when analysing the distribution of cases in the whole community using Poisson, negative binomial and pairwise odds ratio models. However, clustering of cases was observed when specific familial relationships were examined. The risk of HAT for a child was significantly increased if the mother had also had HAT, but it was not influenced by a past history of HAT in the father. Sisters and brothers of cases of HAT had a higher risk of HAT than siblings of individuals who had never had HAT, but no such association was documented for half-sisters and half-brothers. Among married couples, a past history of HAT in one spouse had no impact on the other spouse's risk of HAT. Indirect arguments suggested that familial clustering was a consequence of shared exposure, either sequential or simultaneous, rather than of genetic susceptibility. The existence of familial clustering should be kept in mind when implementing passive or active case-finding activities. PMID:9463655

  12. 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

  13. 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.

  14. 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

  15. [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

  16. Wild chimpanzees are infected by Trypanosoma brucei.

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    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

  17. Wild chimpanzees are infected by Trypanosoma brucei

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    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.

  18. Trypanosome Lytic Factor-1 Initiates Oxidation-stimulated Osmotic Lysis of Trypanosoma brucei brucei.

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    Greene, Amy Styer; Hajduk, Stephen L

    2016-02-01

    Human innate immunity against the veterinary pathogen Trypanosoma brucei brucei is conferred by trypanosome lytic factors (TLFs), against which human-infective T. brucei gambiense and T. brucei rhodesiense have evolved resistance. TLF-1 is a subclass of high density lipoprotein particles defined by two primate-specific apolipoproteins: the ion channel-forming toxin ApoL1 (apolipoprotein L1) and the hemoglobin (Hb) scavenger Hpr (haptoglobin-related protein). The role of oxidative stress in the TLF-1 lytic mechanism has been controversial. Here we show that oxidative processes are involved in TLF-1 killing of T. brucei brucei. The lipophilic antioxidant N,N'-diphenyl-p-phenylenediamine protected TLF-1-treated T. brucei brucei from lysis. Conversely, lysis of TLF-1-treated T. brucei brucei was increased by the addition of peroxides or thiol-conjugating agents. Previously, the Hpr-Hb complex was postulated to be a source of free radicals during TLF-1 lysis. However, we found that the iron-containing heme of the Hpr-Hb complex was not involved in TLF-1 lysis. Furthermore, neither high concentrations of transferrin nor knock-out of cytosolic lipid peroxidases prevented TLF-1 lysis. Instead, purified ApoL1 was sufficient to induce lysis, and ApoL1 lysis was inhibited by the antioxidant DPPD. Swelling of TLF-1-treated T. brucei brucei was reminiscent of swelling under hypotonic stress. Moreover, TLF-1-treated T. brucei brucei became rapidly susceptible to hypotonic lysis. T. brucei brucei cells exposed to peroxides or thiol-binding agents were also sensitized to hypotonic lysis in the absence of TLF-1. We postulate that ApoL1 initiates osmotic stress at the plasma membrane, which sensitizes T. brucei brucei to oxidation-stimulated osmotic lysis. PMID:26645690

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

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    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...

  20. Syndromic algorithms for detection of gambiense human african trypanosomiasis in South Sudan.

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    Palmer, JJ; Surur, EI; Goch, GW; Mayen, MA; Lindner, AK; Pittet, A.; Kasparian, S; Checchi, F.; Whitty, CJ

    2013-01-01

    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...

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

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    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

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

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    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

  3. A Four-Point Screening Method for Assessing Molecular Mechanism of Action (MMOA) Identifies Tideglusib as a Time-Dependent Inhibitor of Trypanosoma brucei GSK3β

    OpenAIRE

    Swinney, Zachary T.; Haubrich, Brad A.; Xia, Shuangluo; Ramesha, Chakk; Gomez, Stephen R.; Guyett, Paul; Mensa-Wilmot, Kojo; Swinney, David C.

    2016-01-01

    Background New therapeutics are needed for neglected tropical diseases including Human African trypanosomiasis (HAT), a progressive and fatal disease caused by the protozoan parasites Trypanosoma brucei gambiense and T. b. rhodesiense. There is a need for simple, efficient, cost effective methods to identify new molecules with unique molecular mechanisms of action (MMOAs). The mechanistic features of a binding mode, such as competition with endogenous substrates and time-dependence can affect...

  4. Analysis of a model of gambiense sleeping sickness in humans and cattle.

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    Ndondo, A M; Munganga, J M W; Mwambakana, J N; Saad-Roy, C M; van den Driessche, P; Walo, R O

    2016-12-01

    Human African Trypanosomiasis (HAT) and Nagana in cattle, commonly called sleeping sickness, is caused by trypanosome protozoa transmitted by bites of infected tsetse flies. We present a deterministic model for the transmission of HAT caused by Trypanosoma brucei gambiense between human hosts, cattle hosts and tsetse flies. The model takes into account the growth of the tsetse fly, from its larval stage to the adult stage. Disease in the tsetse fly population is modeled by three compartments, and both the human and cattle populations are modeled by four compartments incorporating the two stages of HAT. We provide a rigorous derivation of the basic reproduction number [Formula: see text]. For [Formula: see text], the disease free equilibrium is globally asymptotically stable, thus HAT dies out; whereas (assuming no return to susceptibility) for [Formula: see text], HAT persists. Elasticity indices for [Formula: see text] with respect to different parameters are calculated with baseline parameter values appropriate for HAT in West Africa; indicating parameters that are important for control strategies to bring [Formula: see text] below 1. Numerical simulations with [Formula: see text] show values for the infected populations at the endemic equilibrium, and indicate that with certain parameter values, HAT could not persist in the human population in the absence of cattle. PMID:27296784

  5. 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 Trypan...osoma_brucei_S.png Trypanosoma_brucei_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Trypan...osoma+brucei&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 ...

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

    Directory of Open Access Journals (Sweden)

    Nwoha Rosemary Ijeoma Ogechi

    2015-02-01

    Full Text Available 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.

  7. 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.

  8. 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.

  9. 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

  10. Malleable Mitochondrion of Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Verner, Zdeněk; Basu, Somuvro; Benz, C.; Dixit, S.; Dobáková, Eva; Faktorová, Drahomíra; Hashimi, Hassan; Horáková, Eva; Huang, Zhenqiu; Paris, Zdeněk; Peña-Diaz, Priscila; Ridlon, L.; Týč, Jiří; Wildridge, David; Zíková, Alena; Lukeš, Julius

    2015-01-01

    Roč. 315, 2015 Feb 07 (2015), s. 73-151. ISSN 1937-6448 R&D Projects: GA ČR GAP302/12/2513; GA MŠk LL1205; GA MŠk(CZ) EE2.3.30.0032; GA MŠk LH12104; GA ČR GAP305/12/2261 EU Projects: European Commission(XE) 316304 Institutional support: RVO:60077344 Keywords : Kinetoplast * Metabolism * Mitochondrial transport * Mitochondrion * RNA import * T. brucei * Trypanosome * kDNA Subject RIV: EE - Microbiology, Virology Impact factor: 3.419, year: 2014

  11. 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...

  12. 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...

  13. Multiple Triclosan Targets in Trypanosoma brucei

    OpenAIRE

    Paul, Kimberly S.; Bacchi, Cyrus J.; Englund, Paul T.

    2004-01-01

    Trypanosoma brucei genes encoding putative fatty acid synthesis enzymes are homologous to those encoding type II enzymes found in bacteria and organelles such as chloroplasts and mitochondria. It was therefore not surprising that triclosan, an inhibitor of type II enoyl-acyl carrier protein (enoyl-ACP) reductase, killed both procyclic forms and bloodstream forms of T. brucei in culture with 50% effective concentrations (EC50s) of 10 and 13 μM, respectively. Triclosan also inhibited cell-free ...

  14. Performance of parasitological and molecular techniques for the diagnosis and surveillance of gambiense sleeping sickness

    OpenAIRE

    Mumba Ngoyi, Dieudonné; Ali Ekangu, Rosine; Mumvemba Kodi, Marie France; Pyana, Patient Pati; Balharbi, Fatima; Decq, Mélanie; Kande Betu, Victor; Van der Veken, Wim; Sese, Claude; Menten, Joris; Büscher, Philippe; Lejon, Veerle

    2014-01-01

    Objectives: Recently, improvements have been made to diagnostics for gambiense sleeping sickness control but their performance remains poorly documented and may depend on specimen processing prior to examination. In a prospective study in the Democratic Republic of the Congo, we compared the diagnostic performance of several parasite detection techniques, immune trypanolysis and of m18S PCR on whole blood stored in a stabilisation buffer or dried on filter paper. Methods: Individuals with CAT...

  15. 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

  16. Genetic control of resistance to Trypanosoma brucei brucei infection in mice

    Czech Academy of Sciences Publication Activity Database

    Šíma, Matyáš; Havelková, Helena; Quan, L.; Svobodová, M.; Jarošíková, T.; Vojtíšková, Jarmila; Stassen, A. P. M.; Demant, P.; Lipoldová, Marie

    2011-01-01

    Roč. 5, č. 6 (2011), e1173. ISSN 1935-2735 R&D Projects: GA AV ČR IAA500520606; GA MŠk(CZ) LC06009 Grant ostatní: NIH-NCI(US) 1R01CA127162-01 Institutional research plan: CEZ:AV0Z50520514 Keywords : Trypanosoma brucei brucei * mouse recombinant congenic strains * Tbbr Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.716, year: 2011

  17. 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...

  18. An evaluation of Minor Groove Binders as anti-Trypanosoma brucei brucei therapeutics.

    Science.gov (United States)

    Scott, Fraser J; Khalaf, Abedawn I; Giordani, Federica; Wong, Pui Ee; Duffy, Sandra; Barrett, Michael; Avery, Vicky M; Suckling, Colin J

    2016-06-30

    A series of 32 structurally diverse MGBs, derived from the natural product distamycin, was evaluated for activity against Trypanosoma brucei brucei. Four compounds have been found to possess significant activity, in the nanomolar range, and represent hits for further optimisation towards novel treatments for Human and Animal African Trypanosomiases. Moreover, SAR indicates that the head group linking moiety is a significant modulator of biological activity. PMID:27060763

  19. Mitochondrial pyruvate carrier in Trypanosoma brucei.

    Science.gov (United States)

    Štáfková, Jitka; Mach, Jan; Biran, Marc; Verner, Zdeněk; Bringaud, Frédéric; Tachezy, Jan

    2016-05-01

    Pyruvate is a key product of glycolysis that regulates the energy metabolism of cells. In Trypanosoma brucei, the causative agent of sleeping sickness, the fate of pyruvate varies dramatically during the parasite life cycle. In bloodstream forms, pyruvate is mainly excreted, whereas in tsetse fly forms, pyruvate is metabolized in mitochondria yielding additional ATP molecules. The character of the molecular machinery that mediates pyruvate transport across mitochondrial membrane was elusive until the recent discovery of mitochondrial pyruvate carrier (MPC) in yeast and mammals. Here, we characterized pyruvate import into mitochondrion of T. brucei. We identified mpc1 and mpc2 homologs in the T. brucei genome with attributes of MPC protein family and we demonstrated that both proteins are present in the mitochondrial membrane of the parasite. Investigations of mpc1 or mpc2 gene knock-out cells proved that T. brucei MPC1/2 proteins facilitate mitochondrial pyruvate transport. Interestingly, MPC is expressed not only in procyclic trypanosomes with fully activated mitochondria but also in bloodstream trypanosomes in which most of pyruvate is excreted. Moreover, MPC appears to be essential for bloodstream forms, supporting the recently emerging picture that the functions of mitochondria in bloodstream forms are more diverse than it was originally thought. PMID:26748989

  20. 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...

  1. Trypanosoma brucei has a canonical mitochondrial processing peptidase.

    Science.gov (United States)

    Desy, Silvia; Schneider, André; Mani, Jan

    2012-10-01

    Most mitochondrial matrix and inner membrane proteins have N-terminal presequences which serve as import signals. After import these presequences are cleaved by the heterodimeric mitochondrial processing peptidase. In the parasitic protozoa Trypanosoma brucei mitochondrial protein import relies on presequences that are much shorter than in other eukaryotes. How they are processed is unknown. The trypansomal genome encodes four open reading frames that are annotated as mitochondrial processing peptidase. Here we show that RNAi-mediated ablation of two of these proteins leads to a growth arrest and a concomitant accumulation of mitochondrial precursor proteins inside mitochondria. Import experiments using isolated mitochondria from RNAi cell lines reveals that both proteins are required for efficient import and processing of the tested precursor protein. Reciprocal immunoprecipitation demonstrates that the proteins interact with each other. In summary these results show that we have identified the two subunits of the trypanosomal mitochondrial processing peptidase. PMID:22841752

  2. 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.

  3. 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

  4. 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.

  5. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Antitrypanosomal alkaloids from Polyalthia suaveolens (Annonaceae): their effects on three selected glycolytic enzymes of Trypanosoma brucei.

    Science.gov (United States)

    Ngantchou, Igor; Nyasse, Barthélemy; Denier, Colette; Blonski, Casimir; Hannaert, Véronique; Schneider, Bernd

    2010-06-15

    In continuation of our study on medicinal plants of Cameroon, stem barks of Polyalthia suaveolens were phytochemically studied. This investigation yielded a new indolosesquiterpene alkaloid, named polysin (1) and four hitherto known alkaloids (2-5). Polysin (1) appeared as a competitive reversible inhibitor (K(i)=10 microM) of phosphofructo kinase (PFK) of Trypanosoma brucei with respect to fructose-6-phosphate (K(i)/K(M)=0.05) and could be used in the design of new trypanocidal drugs. The other isolated compounds (2-5) also exhibited interesting inhibitory effects on selected glycolytic enzymes (PFK, glyceraldehyde-3-phosphate dehydrogenase and aldolase). PMID:20529682

  9. Action of trypanosomal lipolytic enzymes on the membrane-form variant surface glycoprotein of trypanosoma brucei

    International Nuclear Information System (INIS)

    The membrane-form variant surface glycoprotein (mfVSG) of Trypanosoma brucei is anchored in the plasma membrane by myristoyl residues ester-linked to glycerophosphoethanolamine. The authors have extracted [myristoyl-3H]-mfVSG from trypanosomes incubated with [3H]-myristate and have isolated the protein by reverse phase HPLC. The extraction solvent, 20% acetonitrile in 0.1% trifluoroacetic acid, prevents lipolysis of the mfVSG during isolation. The mfVSG was shown to be homogeneous by SDS-PAGE, with an apparent molecular mass ratio of 66,000. No other proteins were labelled with [3H]-myristate. The major lipolytic enzyme of T. brucei, phospholipase A1, did not release myristate from mfVSG to any significant extent, though the enzyme readily hydrolyzes ester linkages of myristoyl phospholipids and p-nitrophenylmyristate. Trypanosomal membranes contain a phosphodiesterase which releases [3H]-1,2-diglyceride from [3H]-myristoyl-mfVSG. The phospholipase A1 can be separated from the myristoyl-releasing activity (phosphodiesterase) by centrifugation, affinity chromatography and anion-exchange chromatography

  10. Action of trypanosomal lipolytic enzymes on the membrane-form variant surface glycoprotein of trypanosoma brucei

    Energy Technology Data Exchange (ETDEWEB)

    Mellors, A.; Forsberg, C.M.; Hambrey, P.N.

    1986-05-01

    The membrane-form variant surface glycoprotein (mfVSG) of Trypanosoma brucei is anchored in the plasma membrane by myristoyl residues ester-linked to glycerophosphoethanolamine. The authors have extracted (myristoyl-/sup 3/H)-mfVSG from trypanosomes incubated with (/sup 3/H)-myristate and have isolated the protein by reverse phase HPLC. The extraction solvent, 20% acetonitrile in 0.1% trifluoroacetic acid, prevents lipolysis of the mfVSG during isolation. The mfVSG was shown to be homogeneous by SDS-PAGE, with an apparent molecular mass ratio of 66,000. No other proteins were labelled with (/sup 3/H)-myristate. The major lipolytic enzyme of T. brucei, phospholipase A/sub 1/, did not release myristate from mfVSG to any significant extent, though the enzyme readily hydrolyzes ester linkages of myristoyl phospholipids and p-nitrophenylmyristate. Trypanosomal membranes contain a phosphodiesterase which releases (/sup 3/H)-1,2-diglyceride from (/sup 3/H)-myristoyl-mfVSG. The phospholipase A/sub 1/ can be separated from the myristoyl-releasing activity (phosphodiesterase) by centrifugation, affinity chromatography and anion-exchange chromatography.

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

    Science.gov (United States)

    Sun, Ya Nan; No, Joo Hwan; Lee, Ga Young; Li, Wei; Yang, Seo Young; Yang, Gyongseon; Schmidt, Thomas J; Kang, Jong Seong; Kim, Young Ho

    2016-01-01

    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. PMID:27077842

  12. Regulation and spatial organization of PCNA in Trypanosoma brucei

    International Nuclear Information System (INIS)

    Highlights: ► Characterization of the proliferating cell nuclear antigen in Trypanosoma brucei (TbPCNA). ► TbPCNA is a suitable marker to detect replication in T. brucei. ► 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  14. 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.

  15. 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

  16. 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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. 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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  3. 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

  4. 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

  5. Nuclear-encoded mitochondrial tRNAs of Trypanosoma brucei have a modified cytidine in the anticodon loop.

    OpenAIRE

    Schneider, A.; McNally, K P; Agabian, N

    1994-01-01

    The mitochondrial genome of Trypanosoma brucei does not appear to encode any tRNA genes. Isolated organellar tRNAs hybridize to nuclear DNA, suggesting that they are synthesized in the nucleus and subsequently imported into the mitochondrion. Most imported tRNAs have cytosolic counterparts, showing identical mobility on two-dimensional polyacrylamide gels. We have compared three nuclear-encoded mitochondrial tRNAs (tRNA(Lys), tRNA(Leu), tRNA(Tyr)) with their cytosolic isoforms by direct enzym...

  6. Characterization of the mitochondrial inner membrane protein translocator Tim17 from Trypanosoma brucei

    OpenAIRE

    Singha, Ujjal K; PEPRAH, EMMANUEL; Williams, Shuntae; Walker, Robert; Saha, Lipi; Chaudhuri, Minu

    2008-01-01

    Mitochondrial protein translocation machinery in the kinetoplastid parasites, like Trypanosoma brucei, has been characterized poorly. In T. brucei genome data base, one homolog for a protein translocator of mitochondrial inner membrane (Tim) has been found, which is closely related to Tim17 from other species. The T. brucei Tim17 (TbTim17) has a molecular mass 16.2 kDa and it possesses four characteristic transmembrane domains. The protein is localized in the mitochondrial inner membrane. The...

  7. Trypanosoma brucei solanesyl-diphosphate synthase localizes to the mitochondrion

    Czech Academy of Sciences Publication Activity Database

    Lai, D.-H.; Bontempi, E. J.; Lukeš, Julius

    2012-01-01

    Roč. 183, č. 2 (2012), s. 189-192. ISSN 0166-6851 R&D Projects: GA ČR(CZ) GAP305/11/2179 Institutional support: RVO:60077344 Keywords : Trypanosoma brucei * Sleeping sickness * Ubiquinone * Solanesyl-diphosphate synthase * Digitonin permeabilization * In situ tagging Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.734, year: 2012 http://www.sciencedirect.com/science/article/pii/S0166685112000539

  8. 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...

  9. 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 ...

  10. 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.

  11. Single molecule analysis of Trypanosoma brucei DNA replication dynamics.

    Science.gov (United States)

    Calderano, Simone Guedes; Drosopoulos, William C; Quaresma, Marina Mônaco; Marques, Catarina A; Kosiyatrakul, Settapong; McCulloch, Richard; Schildkraut, Carl L; Elias, Maria Carolina

    2015-03-11

    Eukaryotic genome duplication relies on origins of replication, distributed over multiple chromosomes, to initiate DNA replication. A recent genome-wide analysis of Trypanosoma brucei, the etiological agent of sleeping sickness, localized its replication origins to the boundaries of multigenic transcription units. To better understand genomic replication in this organism, we examined replication by single molecule analysis of replicated DNA. We determined the average speed of replication forks of procyclic and bloodstream form cells and we found that T. brucei DNA replication rate is similar to rates seen in other eukaryotes. We also analyzed the replication dynamics of a central region of chromosome 1 in procyclic forms. We present evidence for replication terminating within the central part of the chromosome and thus emanating from both sides, suggesting a previously unmapped origin toward the 5' extremity of chromosome 1. Also, termination is not at a fixed location in chromosome 1, but is rather variable. Importantly, we found a replication origin located near an ORC1/CDC6 binding site that is detected after replicative stress induced by hydroxyurea treatment, suggesting it may be a dormant origin activated in response to replicative stress. Collectively, our findings support the existence of more replication origins in T. brucei than previously appreciated. PMID:25690894

  12. Tracking autophagy during proliferation and differentiation of Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    William R. Proto

    2014-01-01

    Full Text Available Autophagy is a lysosome-dependent degradation mechanism that sequesters target cargo into autophagosomal vesicles. The Trypanosoma brucei genome contains apparent orthologues of several autophagy-related proteins including an ATG8 family. These ubiquitin-like proteins are required for autophagosome membrane formation, but our studies show that ATG8.3 is atypical. To investigate the function of other ATG proteins, RNAi compatible T. brucei were modified to function as autophagy reporter lines by expressing only either YFP-ATG8.1 or YFP-ATG8.2. In the insect procyclic lifecycle stage, independent RNAi down-regulation of ATG3 or ATG7 generated autophagy-defective mutants and confirmed a pro-survival role for autophagy in the procyclic form nutrient starvation response. Similarly, RNAi depletion of ATG5 or ATG7 in the bloodstream form disrupted autophagy, but did not impede proliferation. Further characterisation showed bloodstream form autophagy mutants retain the capacity to undergo the complex cellular remodelling that occurs during differentiation to the procyclic form and are equally susceptible to dihydroxyacetone-induced cell death as wild type parasites, not supporting a role for autophagy in this cell death mechanism. The RNAi reporter system developed, which also identified TOR1 as a negative regulator controlling YFP-ATG8.2 but not YFP-ATG8.1 autophagosome formation, will enable further targeted analysis of the mechanisms and function of autophagy in the medically relevant bloodstream form of T. brucei.

  13. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Infeção experimental por Trypanosoma brucei brucei em modelo murino e estudo da eficácia farmacológica do benznidazol

    OpenAIRE

    Pereira, João Luís Gomes

    2013-01-01

    ABSTRACT - TRYPANOSOMA BRUCEI BRUCEI MURINE EXPERIMENTAL MURINE INFECTION AND STUDIES ON PHARMACOLOCICAL EFFECTIVENESS OF BENZNIDAZOLE - African Trypanosomiasis (AT) is a parasitic disease caused by several species of Trypanosoma, transmitted by diptera of the Glossina genus, also known as the tsetse flies. This disease affects humans and animals, in humans takes the name of Sleeping Sickness, and in animals takes the name of Nagana. Diagnosis can be performed by parasite visualization...

  16. Rab23 is a flagellar protein in Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    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.

  17. 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...

  18. 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.

  19. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  1. 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...

  2. The Phosphoproteome of Bloodstream Form Trypanosoma brucei, Causative Agent of African Sleeping Sickness

    OpenAIRE

    Nett, Isabelle R. E.; Martin, David M. A.; Miranda-Saavedra, Diego; Lamont, Douglas; Barber, Jonathan D.; Mehlert, Angela; Ferguson, Michael A. J.

    2009-01-01

    The protozoan parasite Trypanosoma brucei is the causative agent of human African sleeping sickness and related animal diseases, and it has over 170 predicted protein kinases. Protein phosphorylation is a key regulatory mechanism for cellular function that, thus far, has been studied in T.brucei principally through putative kinase mRNA knockdown and observation of the resulting phenotype. However, despite the relatively large kinome of this organism and the demonstrated essentiality of severa...

  3. Natively Inhibited Trypanosoma brucei Cathepsin B Structure Determined by Using an X-ray Laser

    OpenAIRE

    L. Redecke; Nass, K.; DePonte, D. P.; White, T A; Rehders, D.; Barty, A.; F. Stellato; Liang, M; Barends, T. R. M.; Boutet, S.; Williams, G J; Messerschmidt, M.; Seibert, M. M.; Aquila, A.; Arnlund, D.

    2012-01-01

    The Trypanosoma brucei cysteine protease cathepsin B (TbCatB), which is involved in host protein degradation, is a promising target to develop new treatments against sleeping sickness, a fatal disease caused by this protozoan parasite. The structure of the mature, active form of TbCatB has so far not provided sufficient information for the design of a safe and specific drug against T. brucei. By combining two recent innovations, in vivo crystallization and serial femtosecond crystallography, ...

  4. 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

  5. The Molecular Dynamics of Trypanosoma brucei UDP-Galactose 4′-Epimerase: A Drug Target for African Sleeping Sickness

    OpenAIRE

    Friedman, Aaron J; Durrant, Jacob D.; Pierce, Levi C. T.; McCorvie, Thomas J; Timson, David J; McCammon, J. Andrew

    2012-01-01

    During the past century, several epidemics of human African trypanosomiasis, a deadly disease caused by the protist Trypanosoma brucei, have afflicted sub-Saharan Africa. Over 10 000 new victims are reported each year, with hundreds of thousands more at risk. As current drug treatments are either highly toxic or ineffective, novel trypanocides are urgently needed. The T. brucei galactose synthesis pathway is one potential therapeutic target. Although galactose is essential for T. brucei survi...

  6. 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.

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

    International Nuclear Information System (INIS)

    Highlights: → Inhibiting Δ9 desaturase drastically changes T. brucei's fatty-acid composition. → Isoxyl specifically inhibits the Δ9 desaturase causing a growth arrest. → RNA interference of desaturase expression causes a similar effect. → Feeding T. brucei-infected mice with Isoxyl decreases the parasitemia. → 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 (EC50) of PCF was 1.0 ± 0.2 μM for Isoxyl and 5 ± 2 μM for 10-TS, whereas BSF appeared more susceptible with EC50 values 0.10 0.03 μM (Isoxyl) and 1.0 ± 0.6 μM (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.

  8. Co-infection with Plasmodium berghei and Trypanosoma brucei increases severity of malaria and trypanosomiasis in mice.

    Science.gov (United States)

    Ademola, Isaiah Oluwafemi; Odeniran, Paul Olalekan

    2016-07-01

    Individuals in natural populations may be infected with multiple different parasites at a time. These parasites may interact with each other or act independently in the host, and this may result to varying outcomes on host health and survival. This study therefore aimed at investigating the health impact of co-infection of mice with Plasmodium berghei and Trypanosoma brucei. Forty Swiss albino mice (14-17g) were divided into four groups of ten. Mice in groups A and B received 10(6)P. berghei and groups B and C 10(5)T. brucei, while group D were uninfected. The co-infected mice had higher P. berghei and T. brucei parasitaemia, compared with the mono-infected mice. The co-infected mice had significantly (p<0.05) lower survival rate compared with the mono-infected mice. Co-infection of mice with P. berghei and T. brucei resulted in rapid P. berghei and T. brucei development and increased parasitaemia. The leukocyte numbers significantly (p<0.05) reduced on days 12 and 15 post infection among P. berghei infected mice, in the presence or absence of T. brucei. Anaemia and hypoglycaemia was more severe in the co-infected mice. Therefore, co-infection of mice with P. berghei and T. brucei may increase pathologic impact to the host by increasing parasitaemia. PMID:27021269

  9. Unfolded Protein Response Pathways in Bloodstream-Form Trypanosoma brucei?

    Science.gov (United States)

    Tiengwe, Calvin; Brown, Abigail E N A; Bangs, James D

    2015-11-01

    The unfolded protein response (UPR) is a stress mechanism to cope with misfolded proteins in the early secretory pathway, the hallmark being transcriptional upregulation of endoplasmic reticulum (ER) molecular chaperones such as BiP and protein disulfide isomerase. Despite the lack of transcriptional regulation and the absence of the classical UPR machinery, African trypanosomes apparently respond to persistent ER stress by a UPR-like response, including upregulation of BiP, and a related spliced leader silencing (SLS) response whereby SL RNA transcription is shut down. Initially observed by knockdown of the secretory protein translocation machinery, both responses are also induced by chemical agents known to elicit UPR in mammalian cells (H. Goldshmidt, D. Matas, A. Kabi, A. Carmi, R. Hope, S. Michaeli, PLoS Pathog 6:e1000731, 2010, http://dx.doi.org/10.1371/journal.ppat.1000731). As these findings were generated primarily in procyclic-stage trypanosomes, we have investigated both responses in pathogenic bloodstream-stage parasites. RNA interference (RNAi) silencing of the core translocon subunit Trypanosoma brucei Sec61α (TbSec61α) failed to induce either response. Interestingly, cell growth halted within 16 h of silencing, but sufficient TbSec61α remained to allow full competence for translocation of nascent secretory proteins for up to 24 h, indicating that replication is finely coupled with the capacity to synthesize and transport secretory cargo. Tunicamycin and thapsigargin at concentrations compatible with short-term (4 h) and long-term (24 h) viability also failed to induce any of the indicators of UPR-like or SLS responses. Dithiothreitol (DTT) was lethal at all concentrations tested. These results indicate that UPR-like and SLS responses to persistent ER stress do not occur in bloodstream-stage trypanosomes. PMID:26318397

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Paula Ana Iribarren

    Full Text Available 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.

  12. A haptoglobin-hemoglobin receptor conveys innate immunity to Trypanosoma brucei in humans

    DEFF Research Database (Denmark)

    Vanhollebeke, Benoit; De Muylder, Géraldine; Nielsen, Marianne J; Pays, Annette; Tebabi, Patricia; Dieu, Marc; Raes, Martine; Moestrup, Soren K; Pays, Etienne

    2008-01-01

    The protozoan parasite Trypanosoma brucei is lysed by apolipoprotein L-I, a component of human high-density lipoprotein (HDL) particles that are also characterized by the presence of haptoglobin-related protein. We report that this process is mediated by a parasite glycoprotein receptor, which bi...

  13. The phosphoproteome of bloodstream form Trypanosoma brucei, causative agent of African sleeping sickness.

    Science.gov (United States)

    Nett, Isabelle R E; Martin, David M A; Miranda-Saavedra, Diego; Lamont, Douglas; Barber, Jonathan D; Mehlert, Angela; Ferguson, Michael A J

    2009-07-01

    The protozoan parasite Trypanosoma brucei is the causative agent of human African sleeping sickness and related animal diseases, and it has over 170 predicted protein kinases. Protein phosphorylation is a key regulatory mechanism for cellular function that, thus far, has been studied in T.brucei principally through putative kinase mRNA knockdown and observation of the resulting phenotype. However, despite the relatively large kinome of this organism and the demonstrated essentiality of several T. brucei kinases, very few specific phosphorylation sites have been determined in this organism. Using a gel-free, phosphopeptide enrichment-based proteomics approach we performed the first large scale phosphorylation site analyses for T.brucei. Serine, threonine, and tyrosine phosphorylation sites were determined for a cytosolic protein fraction of the bloodstream form of the parasite, resulting in the identification of 491 phosphoproteins based on the identification of 852 unique phosphopeptides and 1204 phosphorylation sites. The phosphoproteins detected in this study are predicted from their genome annotations to participate in a wide variety of biological processes, including signal transduction, processing of DNA and RNA, protein synthesis, and degradation and to a minor extent in metabolic pathways. The analysis of phosphopeptides and phosphorylation sites was facilitated by in-house developed software, and this automated approach was validated by manual annotation of spectra of the kinase subset of proteins. Analysis of the cytosolic bloodstream form T. brucei kinome revealed the presence of 44 phosphorylated protein kinases in our data set that could be classified into the major eukaryotic protein kinase groups by applying a multilevel hidden Markov model library of the kinase catalytic domain. Identification of the kinase phosphorylation sites showed conserved phosphorylation sequence motifs in several kinase activation segments, supporting the view that

  14. Trypanosoma brucei: Differential requirement of membrane potential for import of proteins into mitochondria in two developmental stages

    OpenAIRE

    Williams, Shuntae; Saha, Lipi; Singha, Ujjal K; Chaudhuri, Minu

    2007-01-01

    Trypanosome alternative oxidase (TAO) and the cytochrome oxidase (COX) are two developmentally regulated terminal oxidases of the mitochondrial electron transport chain in Trypanosoma brucei. Here, we have compared the import of TAO and cytochrome oxidase subunit IV (COIV), two stage specific nuclear encoded mitochondrial proteins, into the bloodstream and procyclic form mitochondria of T. brucei to understand the import processes in two different developmental stages. Under in vitro conditio...

  15. 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% (...

  16. The molecular dynamics of Trypanosoma brucei UDP-galactose 4'-epimerase:a drug target for African sleeping sickness

    OpenAIRE

    Friedman, Aaron J; Durrant, Jacob D.; Pierce, Levi C. T.; McCorvie, Thomas J; Timson, David J; McCammon, J. Andrew

    2012-01-01

    During the past century, several epidemics of human African trypanosomiasis, a deadly disease caused by the protist Trypanosoma brucei, have afflicted sub-Saharan Africa. Over 10 000 new victims are reported each year, with hundreds of thousands more at risk. As current drug treatments are either highly toxic or ineffective, novel trypanocides are urgently needed. The T. brucei galactose synthesis pathway is one potential therapeutic target. Although galactose is essential for T. brucei survi...

  17. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  19. 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 ...

  20. 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...

  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. 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

  3. 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...

  4. 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...

  5. 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

  6. 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...

  7. Mitochondrial tRNA import in Trypanosoma brucei is independent of thiolation and the Rieske protein

    Czech Academy of Sciences Publication Activity Database

    Paris, Zdeněk; RUBIO, M. A. T.; Lukeš, Julius; Alfonzo, J. D.

    2009-01-01

    Roč. 15, č. 7 (2009), s. 1398-1406. ISSN 1355-8382 R&D Projects: GA ČR GA204/06/1558; GA MŠk LC07032; GA MŠk 2B06129 Institutional research plan: CEZ:AV0Z60220518 Keywords : T. brucei * tRNA import * 2-thiolation * RIC * Rieske * Fe-S cluster Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.198, year: 2009

  8. Proteins and lipids of glycosomal membranes from Leishmania tarentolae and Trypanosoma brucei

    OpenAIRE

    Claudia Colasante; Frank Voncken; Theresa Manful; Thomas Ruppert; Tielens, Aloysius G. M.; van Hellemond, Jaap J; Christine Clayton

    2013-01-01

    In kinetoplastid protists, several metabolic pathways, including glycolysis and purine salvage, are located in glycosomes, which are microbodies that are evolutionarily related to peroxisomes. With the exception of some potential transporters for fatty acids, and one member of the mitochondrial carrier protein family, proteins that transport metabolites across the glycosomal membrane have yet to be identified. We show here that the phosphatidylcholine species composition of Trypanosoma brucei...

  9. 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...

  10. Structure of a Trypanosoma brucei α/β-hydrolase fold protein with unknown function

    International Nuclear Information System (INIS)

    T. brucei gene Tb10.6k15.0140 codes for an α/β-hydrolase fold protein of unknown function. The 2.2 Å crystal structure shows that members of this sequence family retain a conserved Ser residue at the expected site of a catalytic nucleophile, but that trypanosomatid sequences lack structural homologs for the other expected residues of the catalytic triad. The structure of a structural genomics target protein, Tbru020260AAA from Trypanosoma brucei, has been determined to a resolution of 2.2 Å using multiple-wavelength anomalous diffraction at the Se K edge. This protein belongs to Pfam sequence family PF08538 and is only distantly related to previously studied members of the α/β-hydrolase fold family. Structural superposition onto representative α/β-hydrolase fold proteins of known function indicates that a possible catalytic nucleophile, Ser116 in the T. brucei protein, lies at the expected location. However, the present structure and by extension the other trypanosomatid members of this sequence family have neither sequence nor structural similarity at the location of other active-site residues typical for proteins with this fold. Together with the presence of an additional domain between strands β6 and β7 that is conserved in trypanosomatid genomes, this suggests that the function of these homologs has diverged from other members of the fold family

  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. Anti-trypanosomal Activity of Potential Inhibitors of Trypanosoma brucei Glycolytic Pathway Enzymes Selected by Docking Studies

    Directory of Open Access Journals (Sweden)

    Clarisse Musanabaganwa

    2014-12-01

    Full Text Available Human African trypanosomiasis (HAT, a potentially fatal protozoan infection caused by tsetse-fl mediated transmission of Trypanosoma brucei (T. Brucei, is largely recognized as a neglected disease. The repertoire of drugs that is effective against the infection is limited and all drugs have several drawbacks including high level of toxicity, diffiult administration regimens, and the resurgence of resistance. At present the biology of the parasite is well studied and a number of technologies are now available which can aid in the identifiation of potential drug targets. This review identifies putative inhibitors of trypanosomal glycolytic enzymes.

  13. 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...

  14. Mitochondrial tRNA import in the parasitic protozoon "Trypanosoma brucei" and its consequences on mitochondrial translation

    OpenAIRE

    Charrière, Fabien; Schneider, André; Linder, Patrick

    2007-01-01

    Le parasite protozoaire Trypanosoma brucei est l’agent pathogène responsable de la maladie du sommeil chez l’homme. En plus de son importance dans le domaine de la lutte contre les maladies tropicales, T. brucei est également un excellent modèle pour la recherche fondamentale car il présente beaucoup de caractéristiques qui lui sont propres. Par exemple, aucun ARN de transfert (ARNt) n’est codé dans le génome mitochondrial. Pour cette raison, les ARNts nécessaires au processus de traduction m...

  15. Phosphorylation-Dependent Protein Interaction with Trypanosoma brucei 14-3-3 Proteins that Display Atypical Target Recognition

    OpenAIRE

    Inoue, Masahiro; Yasuda, Kouichi; Uemura, Haruki; Yasaka, Natsumi; Inoue, Hiroshi; Sei, Yoshitatsu; Horikoshi, Nobuo; Fukuma, Toshihide

    2010-01-01

    Background The 14-3-3 proteins are structurally conserved throughout eukaryotes and participate in protein kinase signaling. All 14-3-3 proteins are known to bind to evolutionally conserved phosphoserine-containing motifs (modes 1 and/or 2) with high affinity. In Trypanosoma brucei, 14-3-3I and II play pivotal roles in motility, cytokinesis and the cell cycle. However, none of the T. brucei 14-3-3 binding proteins have previously been documented. Methodology/Principal Findings Initially we sh...

  16. Identification of the ISWI Chromatin Remodeling Complex of the Early Branching Eukaryote Trypanosoma brucei.

    Science.gov (United States)

    Stanne, Tara M; Narayanan, Mani Shankar; Ridewood, Sophie; Ling, Alexandra; Witmer, Kathrin; Kushwaha, Manish; Wiesler, Simone; Wickstead, Bill; Wood, Jennifer; Rudenko, Gloria

    2015-11-01

    ISWI chromatin remodelers are highly conserved in eukaryotes and are important for the assembly and spacing of nucleosomes, thereby controlling transcription initiation and elongation. ISWI is typically associated with different subunits, forming specialized complexes with discrete functions. In the unicellular parasite Trypanosoma brucei, which causes African sleeping sickness, TbISWI down-regulates RNA polymerase I (Pol I)-transcribed variant surface glycoprotein (VSG) gene expression sites (ESs), which are monoallelically expressed. Here, we use tandem affinity purification to determine the interacting partners of TbISWI. We identify three proteins that do not show significant homology with known ISWI-associated partners. Surprisingly, one of these is nucleoplasmin-like protein (NLP), which we had previously shown to play a role in ES control. In addition, we identify two novel ISWI partners, regulator of chromosome condensation 1-like protein (RCCP) and phenylalanine/tyrosine-rich protein (FYRP), both containing protein motifs typically found on chromatin proteins. Knockdown of RCCP or FYRP in bloodstream form T. brucei results in derepression of silent variant surface glycoprotein ESs, as had previously been shown for TbISWI and NLP. All four proteins are expressed and interact with each other in both major life cycle stages and show similar distributions at Pol I-transcribed loci. They are also found at Pol II strand switch regions as determined with ChIP. ISWI, NLP, RCCP, and FYRP therefore appear to form a single major ISWI complex in T. brucei (TbIC). This reduced complexity of ISWI regulation and the presence of novel ISWI partners highlights the early divergence of trypanosomes in evolution. PMID:26378228

  17. 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

  18. 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...

  19. 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...

  20. 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

  1. Mitochondrial translation factors of Trypanosoma brucei: elongation factor-Tu has a unique subdomain that is essential for its function

    Czech Academy of Sciences Publication Activity Database

    Cristodero, M.; Mani, J.; Oeljeklaus, S.; Aeberhard, L.; Hashimi, Hassan; Ramrath, D.J.F.; Lukeš, Julius; Warscheid, B.; Schneider, A.

    2013-01-01

    Roč. 90, č. 4 (2013), s. 744-755. ISSN 0950-382X R&D Projects: GA ČR GAP305/12/2261 Institutional support: RVO:60077344 Keywords : mitochondrial translation * Trypanosoma brucei * EF-Tu Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.026, year: 2013

  2. Transcription of the procyclic acidic repetitive protein genes of Trypanosoma brucei

    International Nuclear Information System (INIS)

    The procyclic acidic repetitive protein (parp) genes of Trypanosoma brucei encode a small family of abundant surface proteins whose expression is restricted to the procyclic form of the parasite. They are found at two unlinked loci, parpA and parpB; transcription of both loci is developmentally regulated. The region of homology upstream of the A and B parp genes is only 640 base pairs long and may contain sequences responsible for transcriptional initiation and regulation. Transcription upstream of this putative promoter region is not developmentally regulated and is much less active than that of the parp genes; the polymerase responsible is inhibited by alpha-amanitin, whereas that transcribing the parp genes is not. Transcription of the parp genes is strongly stimulated by low levels of UV irradiation. The putative parp promoter, when placed upstream of the chloramphenicol acetyltransferase gene, is sufficient to cause production of chloramphenicol acetyltransferase in a T. brucei DNA transformation assay. Taken together, these results suggest that a promoter for an alpha-amanitin-resistant RNA polymerase lies less than 600 nucleotides upstream of the parp genes

  3. A Gene of the β3-Glycosyltransferase Family Encodes N-Acetylglucosaminyltransferase II Function in Trypanosoma brucei.

    Science.gov (United States)

    Damerow, Manuela; Graalfs, Frauke; Güther, M Lucia S; Mehlert, Angela; Izquierdo, Luis; Ferguson, Michael A J

    2016-06-24

    The bloodstream form of the human pathogen Trypanosoma brucei expresses oligomannose, paucimannose, and complex N-linked glycans, including some exceptionally large poly-N-acetyllactosamine-containing structures. Despite the presence of complex N-glycans in this organism, no homologues of the canonical N-acetylglucosaminyltransferase I or II genes can be found in the T. brucei genome. These genes encode the activities that initiate the elaboration of the Manα1-3 and Manα1-6 arms, respectively, of the conserved trimannosyl-N-acetylchitobiosyl core of N-linked glycans. Previously, we identified a highly divergent T. brucei N-acetylglucosaminyltransferase I (TbGnTI) among a set of putative T. brucei glycosyltransferase genes belonging to the β3-glycosyltransferase superfamily (Damerow, M., Rodrigues, J. A., Wu, D., Güther, M. L., Mehlert, A., and Ferguson, M. A. (2014) J. Biol. Chem. 289, 9328-9339). Here, we demonstrate that TbGT15, another member of the same β3-glycosyltransferase family, encodes an equally divergent N-acetylglucosaminyltransferase II (TbGnTII) activity. In contrast to multicellular organisms, where GnTII activity is essential, TbGnTII null mutants of T. brucei grow in culture and are still infectious to animals. Characterization of the large poly-N-acetyllactosamine containing N-glycans of the TbGnTII null mutants by methylation linkage analysis suggests that, in wild-type parasites, the Manα1-6 arm of the conserved trimannosyl core may carry predominantly linear poly-N-acetyllactosamine chains, whereas the Manα1-3 arm may carry predominantly branched poly-N-acetyllactosamine chains. These results provide further detail on the structure and biosynthesis of complex N-glycans in an important human pathogen and provide a second example of the adaptation by trypanosomes of β3-glycosyltransferase family members to catalyze β1-2 glycosidic linkages. PMID:27189951

  4. Design, Mathematical Modelling, Construction and Testing of Synthetic Gene Network Oscillators to Establish Roseobacter Clade Bacteria and the Protozoan Trypanosoma brucei as Synthetic Biology Chassis.

    OpenAIRE

    Borg, Y.

    2015-01-01

    The aim of this project is to establish Roseobacter marine bacteria and Trypanosoma brucei (T. brucei) protozoa as synthetic biology chassis. This work addresses the gap within synthetic biology resulting from the limited choice of host cells available for use in practice. This was done by developing synthetic bacterial and trypanosomal genetic regulatory networks (GRNs) which function as an oscillator as well as by developing the necessary protocols and set-ups to allow for the analysis of G...

  5. 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

    OpenAIRE

    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 w...

  6. 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

  7. Effects of Trypanosoma brucei tryptophanyl-tRNA synthetases silencing by RNA interference

    Directory of Open Access Journals (Sweden)

    Liliana Torcoroma García

    2007-09-01

    Full Text Available The kinetoplast genetic code deviates from the universal code in that 90% of mitochondrial tryptophans are specified by UGA instead of UGG codons. A single nucleus-encoded tRNA Trp(CCA is used by both nuclear and mitochondria genes, since all kinetoplast tRNAs are imported into the mitochondria from the cytoplasm. To allow decoding of the mitochondrial UGA codons as tryptophan, the tRNA Trp(CCA anticodon is changed to UCA by an editing event. Two tryptophanyl tRNA synthetases (TrpRSs have been identified in Trypanosoma brucei: TbTrpRS1 and TbTrpRS2 which localize to the cytoplasm and mitochondria respectively. We used inducible RNA interference (RNAi to assess the role of TbTrpRSs. Our data validates previous observations of TrpRS as potential drug design targets and investigates the RNAi effect on the mitochondria of the parasite.

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Trypanocidal action of bisphosphonium salts through a mitochondrial target in bloodstream form Trypanosoma brucei

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    Abdulsalam A.M. Alkhaldi

    2016-04-01

    Full Text Available Lipophilic bisphosphonium salts are among the most promising antiprotozoal leads currently under investigation. As part of their preclinical evaluation we here report on their mode of action against African trypanosomes, the etiological agents of sleeping sickness. The bisphosphonium compounds CD38 and AHI-9 exhibited rapid inhibition of Trypanosoma brucei growth, apparently the result of cell cycle arrest that blocked the replication of mitochondrial DNA, contained in the kinetoplast, thereby preventing the initiation of S-phase. Incubation with either compound led to a rapid reduction in mitochondrial membrane potential, and ATP levels decreased by approximately 50% within 1 h. Between 4 and 8 h, cellular calcium levels increased, consistent with release from the depolarized mitochondria. Within the mitochondria, the Succinate Dehydrogenase complex (SDH was investigated as a target for bisphosphonium salts, but while its subunit 1 (SDH1 was present at low levels in the bloodstream form trypanosomes, the assembled complex was hardly detectable. RNAi knockdown of the SDH1 subunit produced no growth phenotype, either in bloodstream or in the procyclic (insect forms and we conclude that in trypanosomes SDH is not the target for bisphosphonium salts. Instead, the compounds inhibited ATP production in intact mitochondria, as well as the purified F1 ATPase, to a level that was similar to 1 mM azide. Co-incubation with azide and bisphosphonium compounds did not inhibit ATPase activity more than either product alone. The results show that, in T. brucei, bisphosphonium compounds do not principally act on succinate dehydrogenase but on the mitochondrial FoF1 ATPase.

  14. 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

  15. 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

  16. 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...

  17. 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.

  18. Dynamics of Mitochondrial RNA-Binding Protein Complex in Trypanosoma brucei and Its Petite Mutant under Optimized Immobilization Conditions

    Czech Academy of Sciences Publication Activity Database

    Huang, Zhenqiu; Kaltenbrunner, S.; Šimková, Eva; Staněk, David; Lukeš, Julius; Hashimi, Hassan

    2014-01-01

    Roč. 13, č. 9 (2014), s. 1232-1240. ISSN 1535-9778 R&D Projects: GA ČR GAP305/12/2261; GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 ; RVO:68378050 Keywords : mitochondrion * Trypanosoma brucei * YFP Subject RIV: EB - Genetics ; Molecular Biology; EB - Genetics ; Molecular Biology (UMG-J) Impact factor: 2.820, year: 2014

  19. 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.

  20. Trypanosoma brucei 29-13 strain is inducible in but not permissive for the tsetse fly vector

    Czech Academy of Sciences Publication Activity Database

    Herder, S.; Votýpka, Jan; Jirků, Milan; Rádrová, J.; Janzen, C. J.; Lukeš, Julius

    2007-01-01

    Roč. 117, č. 1 (2007), s. 111-114. ISSN 0014-4894 R&D Projects: GA MŠk(CZ) LC06009; GA MŠk 2B06129 Grant ostatní: MŠk(CZ) Barrande 2-06-28 Institutional research plan: CEZ:AV0Z60220518 Keywords : Trypanosoma brucei * tsetse * Glossina * GFP * Transmission * midgut infection * tetracycline Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.597, year: 2007

  1. 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...

  2. Dereplication Strategies for Targeted Isolation of New Antitrypanosomal Actinosporins A and B from a Marine Sponge Associated-Actinokineospora sp. EG49

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    Usama Ramadan Abdelmohsen

    2014-03-01

    Full Text Available High resolution Fourier transform mass spectrometry (HRFTMS and nuclear magnetic resonance (NMR spectroscopy were employed as complementary metabolomic tools to dereplicate the chemical profile of the new and antitrypanosomally active sponge-associated bacterium Actinokineospora sp. EG49 extract. Principal Component (PCA, hierarchical clustering (HCA, and orthogonal partial least square-discriminant analysis (OPLS-DA were used to evaluate the HRFTMS and NMR data of crude extracts from four different fermentation approaches. Statistical analysis identified the best culture one-strain-many-compounds (OSMAC condition and extraction procedure, which was used for the isolation of novel bioactive metabolites. As a result, two new O-glycosylated angucyclines, named actinosporins A (1 and B (2, were isolated from the broth culture of Actinokineospora sp. strain EG49, which was cultivated from the Red Sea sponge Spheciospongia vagabunda. The structures of actinosporins A and B were determined by 1D- and 2D-NMR techniques, as well as high resolution tandem mass spectrometry. Testing for antiparasitic properties showed that actinosporin A exhibited activity against Trypanosoma brucei brucei with an IC50 value of 15 µM; however no activity was detected against Leishmania major and Plasmodium falciparum, therefore suggesting its selectivity against the parasite Trypanosoma brucei brucei; the causative agent of sleeping sickness.

  3. 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.

  4. 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.

  5. A Host-Pathogen Interaction Reduced to First Principles: Antigenic Variation in T. brucei.

    Science.gov (United States)

    Hovel-Miner, Galadriel; Mugnier, Monica; Papavasiliou, F Nina; Pinger, Jason; Schulz, Danae

    2015-01-01

    Antigenic variation is a common microbial survival strategy, powered by diversity in expressed surface antigens across the pathogen population over the course of infection. Even so, among pathogens, African trypanosomes have the most comprehensive system of antigenic variation described. African trypanosomes (Trypanosoma brucei spp.) are unicellular parasites native to sub-Saharan Africa, and the causative agents of sleeping sickness in humans and of n'agana in livestock. They cycle between two habitats: a specific species of fly (Glossina spp. or, colloquially, the tsetse) and the bloodstream of their mammalian hosts, by assuming a succession of proliferative and quiescent developmental forms, which vary widely in cell architecture and function. Key to each of the developmental forms that arise during these transitions is the composition of the surface coat that covers the plasma membrane. The trypanosome surface coat is extremely dense, covered by millions of repeats of developmentally specified proteins: procyclin gene products cover the organism while it resides in the tsetse and metacyclic gene products cover it while in the fly salivary glands, ready to make the transition to the mammalian bloodstream. But by far the most interesting coat is the Variant Surface Glycoprotein (VSG) coat that covers the organism in its infectious form (during which it must survive free living in the mammalian bloodstream). This coat is highly antigenic and elicits robust VSG-specific antibodies that mediate efficient opsonization and complement mediated lysis of the parasites carrying the coat against which the response was made. Meanwhile, a small proportion of the parasite population switches coats, which stimulates a new antibody response to the prevalent (new) VSG species and this process repeats until immune system failure. The disease is fatal unless treated, and treatment at the later stages is extremely toxic. Because the organism is free living in the blood, the VSG

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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/.

  11. 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.

  12. Immune mechanisms in trypanosomiasis: Studies in mice using 75Se-labelled Trypanosoma brucei

    International Nuclear Information System (INIS)

    Using trypanosomes labelled in vivo with 75Se-methionine, the ability of normal and immunized mice to remove radiolabelled parasites from their circulation was investigated. It was found that immune animals had the capacity to clear parasites rapidly from their blood essentially as a result of hepatic uptake, whereas normal mice did not have this ability and the parasites remained in the circulation. A series of experiments in actively and passively immunized mice showed that hepatic uptake was closely related to antibody levels and was not markedly influenced by macrophage activation or blockade. In subsequent studies in infected animals it was found that, in contrast to mice with chronic infections, those with acute fulminating parasitaemias were unable to remove radiolabelled trypanosomes from their circulation. It was found that this was not due to impaired macrophage function, but was apparently caused by rapid parasite replication outpacing antibody production so that effective opsonization of the trypanosomes did not occur. A comparison of replication rates of the acute strain of T. brucei with that of a strain which causes a more chronic infection showed that, while their initial rates were similar after day 5 the 'chronic' strain changed to a much slower replication rate and this allowed antibody to rise to effective levels. In contrast to the findings of other workers, there was no evidence that the parasite caused any significant suppression of antibody responses in these acute infections. (author)

  13. 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.

  14. 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.

  15. 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

  16. 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 ...

  17. 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.

  18. 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

  19. Trypanosoma brucei TIF2 and TRF Suppress VSG Switching Using Overlapping and Independent Mechanisms

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    Jehi, Sanaa E.; Nanavaty, Vishal; Li, Bibo

    2016-01-01

    Trypanosoma brucei causes debilitating human African trypanosomiasis and evades the host’s immune response by regularly switching its major surface antigen, VSG, which is expressed exclusively from subtelomeric loci. We previously showed that two interacting telomere proteins, TbTRF and TbTIF2, are essential for cell proliferation and suppress VSG switching by inhibiting DNA recombination events involving the whole active VSG expression site. We now find that TbTIF2 stabilizes TbTRF protein levels by inhibiting their degradation by the 26S proteasome, indicating that decreased TbTRF protein levels in TbTIF2-depleted cells contribute to more frequent VSG switching and eventual cell growth arrest. Surprisingly, although TbTIF2 depletion leads to more subtelomeric DNA double strand breaks (DSBs) that are both potent VSG switching inducers and detrimental to cell viability, TbTRF depletion does not increase the amount of DSBs inside subtelomeric VSG expression sites. Furthermore, expressing an ectopic allele of F2H-TbTRF in TbTIF2 RNAi cells allowed cells to maintain normal TbTRF protein levels for a longer frame of time. This resulted in a mildly better cell growth and partially suppressed the phenotype of increased VSG switching frequency but did not suppress the phenotype of more subtelomeric DSBs in TbTIF2-depleted cells. Therefore, TbTIF2 depletion has two parallel effects: decreased TbTRF protein levels and increased subtelomeric DSBs, both resulting in an acute increased VSG switching frequency and eventual cell growth arrest. PMID:27258069

  20. Widespread variation in transcript abundance within and across developmental stages of Trypanosoma brucei

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    Kifer Charles T

    2009-10-01

    Full Text Available Abstract Background Trypanosoma brucei, the causative agent of African sleeping sickness, undergoes a complex developmental cycle that takes place in mammalian and insect hosts and is accompanied by changes in metabolism and cellular morphology. While differences in mRNA expression have been described for many genes, genome-wide expression analyses have been largely lacking. Trypanosomatids represent a unique case in eukaryotes in that they transcribe protein-coding genes as large polycistronic units, and rarely regulate gene expression at the level of transcription initiation. Results Here we present a comprehensive analysis of mRNA expression in several stages of parasite development. Utilizing microarrays that have multiple copies of multiple probes for each gene, we were able to demonstrate with a high degree of statistical confidence that approximately one-fourth of genes show differences in mRNA expression levels in the stages examined. These include complex patterns of gene expression within gene families, including the large family of variant surface glycoproteins (VSGs and their relatives, where we have identified a number of constitutively expressed family members. Furthermore, we were able to assess the relative abundance of all transcripts in each stage, identifying the genes that are either weakly or highly expressed. Very few genes show no evidence of expression. Conclusion Despite the lack of gene regulation at the level of transcription initiation, our results reveal extensive regulation of mRNA abundance associated with different life cycle and growth stages. In addition, analysis of variant surface glycoprotein gene expression reveals a more complex picture than previously thought. These data provide a valuable resource to the community of researchers studying this lethal agent.

  1. 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.

  2. 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

  3. The 2’-O-ribose methyltransferase for cap 1 of spliced leader RNA and U1 small nuclear RNA in Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Zamudio, J. R.; Mittra, B.; Foldynová-Trantírková, Silvie; Zeiner, G. M.; Lukeš, Julius; Bujnicki, J. M.; Sturm, N. R.; Campbell, D. A.

    2007-01-01

    Roč. 27, č. 17 (2007), s. 6084-6092. ISSN 0270-7306 R&D Projects: GA MŠk 2B06129; GA MŠk LC07032 Institutional research plan: CEZ:AV0Z60220518 Keywords : methylation * Trypanosoma brucei * methyltransferase * RNA interference Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.420, year: 2007

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Synthesis of novel amide and urea derivatives of thiazol-2-ethylamines and their activity against Trypanosoma brucei rhodesiense.

    Science.gov (United States)

    Patrick, Donald A; Wenzler, Tanja; Yang, Sihyung; Weiser, Patrick T; Wang, Michael Zhuo; Brun, Reto; Tidwell, Richard R

    2016-06-01

    2-(2-Benzamido)ethyl-4-phenylthiazole (1) was one of 1035 molecules (grouped into 115 distinct scaffolds) found to be inhibitory to Trypanosoma brucei, the pathogen causing human African trypanosomiasis, at concentrations below 3.6μM and non-toxic to mammalian (Huh7) cells in a phenotypic high-throughput screen of a 700,000 compound library performed by the Genomics Institute of the Novartis Research Foundation (GNF). Compound 1 and 72 analogues were synthesized in this lab by one of two general pathways. These plus 10 commercially available analogues were tested against T. brucei rhodesiense STIB900 and L6 rat myoblast cells (for cytotoxicity) in vitro. Forty-four derivatives were more potent than 1, including eight with IC50 values below 100nM. The most potent and most selective for the parasite was the urea analogue 2-(2-piperidin-1-ylamido)ethyl-4-(3-fluorophenyl)thiazole (70, IC50=9nM, SI>18,000). None of 33 compounds tested were able to cure mice infected with the parasite; however, seven compounds caused temporary reductions of parasitemia (⩾97%) but with subsequent relapses. The lack of in vivo efficacy was at least partially due to their poor metabolic stability, as demonstrated by the short half-lives of 15 analogues against mouse and human liver microsomes. PMID:27102161

  9. 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.

  10. 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

  11. Influence of trypanocidal therapy on the haematology of vervet monkeys experimentally infected with Trypanosoma brucei rhodesiense.

    Science.gov (United States)

    Ngotho, Maina; Kagira, John M; Kariuki, Christopher; Maina, Naomi; Thuita, John K; Mwangangi, David M; Farah, Idle O; Hau, Jann

    2011-07-01

    The aim of this study was to characterise the sequential haematological changes in vervet monkeys infected with Trypanosoma brucei rhodesiense and subsequently treated with sub-curative diminazene aceturate (DA) and curative melarsoprol (MelB) trypanocidal drugs. Fourteen vervet monkeys, on a serial timed-kill pathogenesis study, were infected intravenously with 10(4) trypanosomes of a stabilate T. b. rhodesiense KETRI 2537. They were treated with DA at 28 days post infection (dpi) and with MelB following relapse of infection at 140 dpi. Blood samples were obtained from the monkeys weekly, and haematology conducted using a haematological analyser. All the monkeys developed a disease associated with macrocytic hypochromic anaemia characterised by a reduction in erythrocytes (RBC), haemoglobin (HB), haematocrit (HCT), mean cell volume (MCV), platelet count (PLT), and an increase in the red cell distribution width (RDW) and mean platelet volume (MPV). The clinical disease was characteristic of human African trypanosomiasis (HAT) with a pre-patent period of 3 days. Treatment with DA cleared trypanosomes from both the blood and cerebrospinal fluid (CSF). The parasites relapsed first in the CSF and later in the blood. This treatment normalised the RBC, HCT, HB, PLT, MCV, and MPV achieving the pre-infection values within two weeks while RDW took up to 6 weeks to attain pre-infection levels after treatment. Most of the parameters were later characterised by fluctuations, and declined at one to two weeks before relapse of trypanosomes in the haemolymphatic circulation. Following MelB treatment at 140 dpi, most values recovered within two weeks and stabilised at pre-infection levels, during the 223 days post treatment monitoring period. It is concluded that DA and MelB treatments cause similar normalising changes in the haematological profiles of monkeys infected with T. b. rhodesiense, indicating the efficacy of the drugs. The infection related changes in haematology

  12. 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

  13. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    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. 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

  18. 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

  19. Population genetics of Trypanosoma brucei circulating in Glossina palpalis palpalis and domestic animals of the Fontem sleeping sickness focus of Cameroon

    OpenAIRE

    Simo, Gustave; Njitchouang, Guy Roger; Melachio, Tresor Tito Tanekou; Njiokou, Flobert; Cuny, Gerard; Tazoacha, Asonganyi

    2014-01-01

    Background: Human African Trypanosomiasis is still a public health threat in Cameroon. To assess Trypanosoma brucei strains circulating in the Fontem sleeping sickness focus, we conducted a genetic structure study using microsatellites to assess genotypes circulating in both tsetse flies and domestic animals. Method: For this study, pyramidal traps were set up and 2695 tsetse flies were collected and 1535 (57%) living flies were dissected and their mid- guts collected. Furthermore, blood samp...

  20. Characterization of a novel trans-sialidase of Trypanosoma brucei procyclic trypomastigotes and identification of procyclin as the main sialic acid acceptor

    OpenAIRE

    1993-01-01

    Here we report the presence of a trans-sialidase on the surface of Trypanosoma brucei culture-derived procyclic trypomastigotes. The enzyme is not detected in lysates of bloodstream trypomastigotes enriched for either stumpy or slender forms. The trans-sialidase catalyzes the transfer of alpha(2-3)-linked sialic acid residues to lactose. beta-galactopyranosyl residues are at least 100 times better acceptors for sialic acid than alpha-galactopyranosyl residues. In the absence of efficient acce...

  1. 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.

  2. 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...

  3. The de novo and salvage pathways of GDP-mannose biosynthesis are both sufficient for the growth of bloodstream-form Trypanosoma brucei

    OpenAIRE

    Kuettel, Sabine; Wadum, Majken C T; Güther, Maria Lucia S; Mariño, Karina; Riemer, Carolin; Ferguson, Michael A. J.

    2012-01-01

    Summary The sugar nucleotide GDP-mannose is essential for Trypanosoma brucei. Phosphomannose isomerase occupies a key position on the de novo pathway to GDP-mannose from glucose, just before intersection with the salvage pathway from free mannose. We identified the parasite phosphomannose isomerase gene, confirmed that it encodes phosphomannose isomerase activity and localized the endogenous enzyme to the glycosome. We also created a bloodstream-form conditional null mutant of phosphomannose ...

  4. 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.

  5. 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

  6. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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

  9. 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

    Directory of Open Access Journals (Sweden)

    Nwoha Rosemary Ijeoma Ogechi

    2015-06-01

    Full Text Available 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 < 0.05 and peaked at the 3rd week after vaccination. Following infections, there were marked significant decreases (P < 0.05 in the antibody production against rabies in GPII, GPIII and GPIV. The significant decrease (P < 0.05 in antibody titer was highest in the conjunct groups (GPIII and GPIV compared to the single infection (GPII. Treatment with diminazene aceturate and mebendazole did not significantly improve antibody response in the dogs. A secondary vaccination administered at the 12th week after the primary vaccination significantly increased (P < 0.05 the antibody titer with a peak at the 3rd week after the secondary vaccination. Conclusions: It was therefore concluded

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. RNA interference analyses suggest a transcript-specific regulatory role for mitochondrial RNA-binding proteins MRP1 and MRP2 in RNA editing and other RNA processing in Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Horáková, Eva; Van Den Burg, J.; Zíková, Alena; Ernst, N. L.; Stuart, K.; Benne, R.; Lukeš, Julius

    2005-01-01

    Roč. 280, č. 4 (2005), s. 2429-2438. ISSN 0021-9258 R&D Projects: GA AV ČR IAA6022903 Institutional research plan: CEZ:AV0Z60220518 Keywords : Trypanosoma brucei * RNA editing * interference RNA Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.854, year: 2005

  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. Comparative analysis of respiratory chain and oxidative phosphorylation in Leishmania tarentolae, Crithidia fasciculata, Phytomonas serpens and procyclic stage of Trypanosoma brucei.

    Science.gov (United States)

    Verner, Zdeněk; Cermáková, Petra; Skodová, Ingrid; Kováčová, Bianka; Lukeš, Julius; Horváth, Anton

    2014-01-01

    Trypanosomatids are unicellular parasites living in a wide range of host environments, which to large extent shaped their mitochondrial energy metabolism, resulting in quite large differences even among closely related flagellates. In a comparative manner, we analyzed the activities and composition of mitochondrial respiratory complexes in four species (Leishmania tarentolae, Crithidia fasciculata, Phytomonas serpens and Trypanosoma brucei), which represent the main model trypanosomatids. Moreover, we measured the activity of mitochondrial glycerol-3-phosphate dehydrogenase, the overall oxygen consumption and the mitochondrial membrane potential in each species. The comparative analysis suggests an inverse relationship between the activities of respiratory complexes I and II, as well as the overall activity of the canonical complexes and glycerol-3-phosphate dehydrogenase. Our comparative analysis shows that mitochondrial functions are highly variable in these versatile parasites. PMID:24556248

  17. 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.

  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. 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.

  20. 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.

  1. 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

  2. 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

  3. Proteins and lipids of glycosomal membranes from Leishmania tarentolae and Trypanosoma brucei [v1; ref status: indexed, http://f1000r.es/x1

    Directory of Open Access Journals (Sweden)

    Claudia Colasante

    2013-01-01

    Full Text Available In kinetoplastid protists, several metabolic pathways, including glycolysis and purine salvage, are located in glycosomes, which are microbodies that are evolutionarily related to peroxisomes. With the exception of some potential transporters for fatty acids, and one member of the mitochondrial carrier protein family, proteins that transport metabolites across the glycosomal membrane have yet to be identified. We show here that the phosphatidylcholine species composition of Trypanosoma brucei glycosomal membranes resembles that of other cellular membranes, which means that glycosomal membranes are expected to be impermeable to small hydrophilic molecules unless transport is facilitated by specialized membrane proteins. Further, we identified 464 proteins in a glycosomal membrane preparation from Leishmania tarentolae. The proteins included approximately 40 glycosomal matrix proteins, and homologues of peroxisomal membrane proteins - PEX11, GIM5A and GIM5B; PXMP4, PEX2 and PEX16 - as well as the transporters GAT1 and GAT3. There were 27 other proteins that could not be unambiguously assigned to other compartments, and that had predicted trans-membrane domains. However, no clear candidates for transport of the major substrates and intermediates of energy metabolism were found. We suggest that, instead, these metabolites are transported via pores formed by the known glycosomal membrane proteins.

  4. 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

  5. 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.

  6. 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...

  7. 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...

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

    Directory of Open Access Journals (Sweden)

    James Nyabuga Nyariki

    2015-03-01

    Full Text Available 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<0.05 different compared to un-supplemented groups, and clearly indicated that coenzyme Q10 prevented full blown splenomegaly pathogenesis by T. b. rhodesiense. A significant (P<0.05 increase in hemoglobin levels and red blood cells was observed in coenzyme Q10 mice compared to those infected and un-supplemented with coenzyme Q10. 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.

  9. Glycolipid precursors for the membrane anchor of Trypanosoma brucei variant surface glycoproteins. II. Lipid structures of phosphatidylinositol-specific phospholipase C sensitive and resistant glycolipids

    International Nuclear Information System (INIS)

    A common diagnostic feature of glycosylinositol phospholipid (GPI)-anchored proteins is their release from the membrane by a phosphatidylinositol-specific phospholipase C (PI-PLC). However, some GPI-anchored proteins are resistant to this enzyme. The best characterized example of this subclass is the human erythrocyte acetylcholinesterase, where the structural basis of PI-PLC resistance has been shown to be the acylation of an inositol hydroxyl group(s). Both PI-PLC-sensitive and resistant GPI-anchor precursors (P2 and P3, respectively) have been found in Trypanosoma brucei, where the major surface glycoprotein is anchored by a PI-PLC-sensitive glycolipid anchor. The accompanying paper shows that P2 and P3 have identical glycans, indistinguishable from the common core glycan found on all the characterized GPI protein anchors. This paper shows that the single difference between P2 and P3, and the basis for the PI-PLC insusceptibility of P3, is a fatty acid, ester-linked to the inositol residue in P3. The inositol-linked fatty acid can be removed by treatment with mild base to restore PI-PLC sensitivity. Biosynthetic labeling experiments with [3H]palmitic acid and [3H]myristic acid show that [3H]palmitic acid specifically labels the inositol residue in P3 while [3H]myristic acid labels the diacylglycerol portion. Possible models to account for the simultaneous presence of PI-PLC-resistant and sensitive glycolipids are discussed in the context of available information on the biosynthesis of GPI-anchors

  10. 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.

  11. 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...

  12. Sleeping Sickness and Nagana Disease

    OpenAIRE

    Steverding, Dietmar

    2016-01-01

    The hemoflagellate Trypanosoma brucei is the causative agent of human and animal African trypanosomiasis, also known as sleeping sickness and nagana disease, respectively. The infec-tious disease is transmitted by the bite of infected tsetse flies and afflicts mainly rural popula-tions in sub-Saharan Africa. The subspecies T. b. gambiense and T. b. rhodesiense are responsi-ble for the two forms of human African trypanosomiasis, the West and East African sleeping sickness, respectively. A thir...

  13. Molecular differential diagnosis of African Trypanosomosis in Uganda

    International Nuclear Information System (INIS)

    Out of 106 Trypanosomal DNAs from infected domestic animals, 77 (72.6%) were resolved into different Trypanosome species using primers based on ribosomal internal transcribed spacer-1 region in a single PCR (ITS-PCR). The remaining 29 (27.4%) Trypanosomal DNA samples were negative by ITS-PCR, but were positive by TBR-PCR, indicating that they were Trypanozoon Trypanosomes where the ITS-PCR could not resolve their identities. This was possibly due to the low amounts of DNA in the extracts which could not be picked up by ITS-PCR. The TBR-PCR was able to resolve all 106 Trypanosome isolates into 88 Trypanozoon and 18 others, which were identified and confirmed as T.congolense (6) and T.vivax (12) Trypanosomes. In addition, a total of 58 (89.2%) of the 65 (53 from cows and 12 from pigs) Trypanosome isolates from domestic animals in T.b.gambiense endemic areas in North West Uganda were positive by TBR-PCR, indicating that they were Trypanozoon Trypanosomes while 7 (10.8%) of the Trypanosome isolates were TBR-PCR negative, indicating that they were possibly not T.brucei ssp and could be T.congolense, T.vivax or T.theileri. Indeed, the 7 Trypanosome isolates were confirmed to be T.congolense (2) and T.vivax (5) using species specific primers. Furthermore, 31 of the 58 TBR-PCR positive Trypanosomal DNA samples analysed were TgsGP-PCR negative, indicating that they were not T.b.gambiense and hence no domestic animals identified as reservoir of T.b.gambiense. Additionally, all the 31 Trypanosomal DNA samples were SRA-PCR negative, indicating that there is probably no mixed infection of the two diseases, T.b.gambiense and T.b.rhodesiense in North West Uganda. Analysis of Trypanosomes derived from domestic animals from T.b.rhodesiense endemic areas in South East Uganda showed that, 79 (90.8%) of the 87 Trypanosomes isolated from cattle were positive by TBR-PCR, indicating that they were Trypanozoon while 8 (9.2%) were negative, suggesting that they could be T.vivax, T

  14. 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

    tRNA is the most heavily modified of all RNA types, with typically 10-20% of the residues being post-transcriptionally altered. Unravelling the modification pattern of a tRNA is a challenging task; there are 92 currently known tRNA modifications [1], many of which are chemically similar....... 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 was...... MALDI-TOF MS of two independent digests of the tRNA, with RNase A and RNase T1, respectively. This revealed digestion products harbouring mass-changing modifications. Next, the modifications were mapped at the nucleotide level in the RNase products by tandem MS. Comparison with the sequence of the...

  15. Alternativ isolering i Tyskland

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place

    2001-01-01

    Resume af rapport om brugen af alternativ isolering i Tyskland, som er udarbejdet af Teknologisk Insititut under Energistyrelsens udviklingsprogram "Miljø- og arbejdsmiljøvenlig isolering"......Resume af rapport om brugen af alternativ isolering i Tyskland, som er udarbejdet af Teknologisk Insititut under Energistyrelsens udviklingsprogram "Miljø- og arbejdsmiljøvenlig isolering"...

  16. 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 ...

  17. 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)

  18. Development of multiplex serological assay for the detection of human African trypanosomiasis.

    Science.gov (United States)

    Nzou, Samson Muuo; Fujii, Yoshito; Miura, Masashi; Mwau, Matilu; Mwangi, Anne Wanjiru; Itoh, Makoto; Salam, Md Abdus; Hamano, Shinjiro; Hirayama, Kenji; Kaneko, Satoshi

    2016-04-01

    Human African trypanosomiasis (HAT) is a disease caused by Kinetoplastid infection. Serological tests are useful for epidemiological surveillance. The aim of this study was to develop a multiplex serological assay for HAT to assess the diagnostic value of selected HAT antigens for sero-epidemiological surveillance. We cloned loci encoding eight antigens from Trypanosoma brucei gambiense, expressed the genes in bacterial systems, and purified the resulting proteins. Antigens were subjected to Luminex multiplex assays using sera from HAT and VL patients to assess the antigens' immunodiagnostic potential. Among T. b. gambiense antigens, the 64-kDa and 65-kDa invariant surface glycoproteins (ISGs) and flagellar calcium binding protein (FCaBP) had high sensitivity for sera from T. b. gambiense patients, yielding AUC values of 0.871, 0.737 and 0.858 respectively in receiver operating characteristics (ROC) analysis. The ISG64, ISG65, and FCaBP antigens were partially cross-reactive to sera from Trypanosoma brucei rhodesiense patients. The GM6 antigen was cross-reactive to sera from T. b. rhodesiense patients as well as to sera from VL patients. Furthermore, heterogeneous antibody responses to each individual HAT antigen were observed. Testing for multiple HAT antigens in the same panel allowed specific and sensitive detection. Our results demonstrate the utility of applying multiplex assays for development and evaluation of HAT antigens for use in sero-epidemiological surveillance. PMID:26519611

  19. 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 ...

  20. Isolated Galaxies and Isolated Satellite Systems

    CERN Document Server

    Ann, H B; Choi, Yun-Young

    2009-01-01

    We search for isolated galaxies using a volume-limited sample of galaxies with 0.02r_{vir,nei} and \\rho <\\bar{\\rho} well segregates the CIG galaxies. We confirm the morphology conformity between the host and their satellites, which suggests importance of hydrodynamic interaction among galaxies within their virial radii in galaxy evolution.

  1. 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

  2. Isolating the shaft

    International Nuclear Information System (INIS)

    Paper describes the environment contact preventing isolation of the shaft used to dispose off waste at the Dounreay site (Great Britain) and containing a mixture of radioactive and chemical waste. Well drilling, hydraulic testing, ability to work of isolation are phases of the working. Application of remote controlled transport facility for the waste removal from horizontal tunnel is discussed. Financial problems are treated

  3. 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

  4. 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.

  5. 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.

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

  7. 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...

  8. Lever mechanism for vibration isolation

    Directory of Open Access Journals (Sweden)

    Mitchell Gohnert

    2010-04-01

    Full Text Available By introducing lever mechanism into the conventional vibration isolation system, new vibration isolation systems such as lever-damper isolator (LDI, lever-spring isolator (LSI and lever-spring-mass isolator (LSMI can be developed. The transmissibility of LDI, transmissibility of LSI and that of LSMI are obtained analytically. With numerical simulation, the vibration isolation performance of these systems and the effect of parameters on the performance are investigated. The results show that the performance of traditional vibration isolator can be improved by the introducing of lever mechanism. The results also show that the new systems have less constraint in design.

  9. Primary isolated hepatic tuberculosis

    International Nuclear Information System (INIS)

    Isolated hepatic tuberculosis without pulmonary or bowel involvement is a diagnostic challenge and can cause considerable morbidity. A young lady from Lahore presented with fever, pain in right hypochondria, nausea and weight loss. CT scan of abdomen showed multiple small hypodense non-enhancing lesions and a heterogeneous texture of liver. Biopsy confirmed the diagnosis of hepatic tuberculosis. It was concluded a case of isolated hepatic tuberculosis without evidence of other primary sites involvement. It is important to consider tuberculosis in the differential diagnosis when suspecting lymphoproliferative or metastatic diseases in a patient with vague symptoms and abnormal hepatic texture on CT. (author)

  10. Proteoglycan isolation and analysis

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    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 of...

  11. Emotion regulation during isolation

    Czech Academy of Sciences Publication Activity Database

    Poláčková Šolcová, Iva; Šolcová, Iva

    2012-01-01

    Roč. 47, Suppl. 1 (2012). ISSN 0020-7594. [International Congress of Psychology /30./. 22.07.2012-27.07.2012, Cape Town] R&D Projects: GA ČR(CZ) GAP407/11/2226 Institutional support: RVO:68081740 Keywords : emotion regulation * isolation * Mars500 Subject RIV: AN - Psychology

  12. 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.

  13. Isolated mucosal Leishmaniasis

    OpenAIRE

    Deepak Sundriyal; Naveen Kumar; Raj Kumar; Brijesh Sharma

    2013-01-01

    Leishmaniasis is a term used to define a group of clinical syndrome caused by various species of parasite Leishmania. Three main clinical types of leishmaniasis are visceral leishmaniasis, cutaneous leishmaniasis and mucocutaneous leishmaniasis. However, isolated presentation as mucosal disease is rare. We report a case of primarily mucosal leishmaniasis.

  14. 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.

  15. Isolating Triggered Star Formation

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Elizabeth J.; Arnold, Jacob A.; /UC, Irvine; Zentner, Andrew R.; /KICP, Chicago /Chicago U., EFI; Bullock, James S.; /UC, Irvine; Wechsler, Risa H.; /KIPAC, Menlo

    2007-09-12

    Galaxy pairs provide a potentially powerful means of studying triggered star formation from galaxy interactions. We use a large cosmological N-body simulation coupled with a well-tested semi-analytic substructure model to demonstrate that the majority of galaxies in close pairs reside within cluster or group-size halos and therefore represent a biased population, poorly suited for direct comparison to 'field' galaxies. Thus, the frequent observation that some types of galaxies in pairs have redder colors than 'field' galaxies is primarily a selection effect. We use our simulations to devise a means to select galaxy pairs that are isolated in their dark matter halos with respect to other massive subhalos (N= 2 halos) and to select a control sample of isolated galaxies (N= 1 halos) for comparison. We then apply these selection criteria to a volume-limited subset of the 2dF Galaxy Redshift Survey with M{sub B,j} {le} -19 and obtain the first clean measure of the typical fraction of galaxies affected by triggered star formation and the average elevation in the star formation rate. We find that 24% (30.5 %) of these L* and sub-L* galaxies in isolated 50 (30) h{sup -1} kpc pairs exhibit star formation that is boosted by a factor of {approx}> 5 above their average past value, while only 10% of isolated galaxies in the control sample show this level of enhancement. Thus, 14% (20 %) of the galaxies in these close pairs show clear triggered star formation. Our orbit models suggest that 12% (16%) of 50 (30) h{sup -1} kpc close pairs that are isolated according to our definition have had a close ({le} 30 h{sup -1} kpc) pass within the last Gyr. Thus, the data are broadly consistent with a scenario in which most or all close passes of isolated pairs result in triggered star formation. The isolation criteria we develop provide a means to constrain star formation and feedback prescriptions in hydrodynamic simulations and a very general method of understanding

  16. 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.

  17. Spheres of isolation: adaptation of isolation levels to transactional workflow

    OpenAIRE

    Guabtni, Adnene; Charoy, François; Godart, Claude

    2005-01-01

    In Workflow Management Systems (WFMSs), transaction isolation is managed most of the time by the underlying database system using ANSI SQL strategies. These strategies do not take sufficiently into account process aspects. Our work consists in studying with more depth the relation between isolation strategy and process dimension as well as the real isolation needs in workflow environments. To carry out these needs, we define `spheres of isolation' inspired from `spheres of control' proposed b...

  18. 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

  19. 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.

  20. 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

  1. Dynamic Isolated Domains

    OpenAIRE

    Nyman, Thomas

    2014-01-01

    Operating System-level Virtualization is virtualization technology based on running multiple isolated userspace instances, commonly referred to as containers, on top of a single operating system kernel. The fundamental difference compared to traditional virtualization is that the targets of virtualization in OS-level virtualization are kernel resources, not hardware. OS-level virtualization is used to implement Bring Your Own Device (BYOD) policies on contemporary mobile platforms. Current co...

  2. 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.

  3. Galvanically Isolated Modular Converter

    OpenAIRE

    Christe, Alexandre; Dujic, Drazen

    2016-01-01

    Direct current (DC) electrical grids are already a reality in low voltage (LV) telecom distribution systems and point-to-point high voltage DC transmission. Medium voltage (MV) domain, despite its big potential, still suffers from a lack of suitable conversion and protection technologies. This study presents a bidirectional, galvanically isolated, high power converter for interface of emerging MVDC grids with readily available LVAC grids. To achieve high conversion efficiency, the integration...

  4. 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.

  5. 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....

  6. 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...

  7. 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

  8. The molecular basis of livestock disease as illustrated by African trypanosomiasis

    International Nuclear Information System (INIS)

    African trypanosomes are protozoan parasites, most species of which are transmitted by tsetse flies. They reside in the mammalian bloodstream and evade the immune system by periodically switching the major protein on their surface - a phenomenon called antigenic variation, mediated by gene rearrangements in the trypanosome genome. The trypanosomes eventually enter the central nervous system and cause a fatal disease, commonly called ngana in domestic cattle and sleeping sickness in humans. Two sub-species of Trypanosoma brucei infect humans (T. b. rhodesiense and T. b. gambiense) and one sub-species does not survive in humans (T. b. brucei) because it is lysed by the human-specific serum protein, apolipoprotein L-I. Wild animals in Africa have other (less well understood) molecular mechanisms of suppressing the number of African trypanosomes in the blood, and some indigenous breeds of African cattle also display a partial 'trypanotolerance' whose genetic loci have recently been mapped. (author)

  9. 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

  10. 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

  11. 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...

  12. 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...

  13. 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....

  14. 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...

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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...

  20. Wild chimpanzees are infected by Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Jirků, Milan; Votýpka, Jan; Petrželková, Klára Judita; Jirků-Pomajbíková, K.; Kriegová, Eva; Vodička, R.; Lankester, F.; Leendertz, S. A. J.; Wittig, R. M.; Boesch, Ch.; Modrý, David; Ayala, F. J.; Leendertz, F. H.; Lukeš, Julius

    2015-01-01

    Roč. 4, č. 3 (2015), s. 277-282. ISSN 2213-2244 R&D Projects: GA MŠk(CZ) EE2.3.30.0032 EU Projects: European Commission(XE) 316304 Institutional support: RVO:60077344 Keywords : Trypanosomes * Chimpanzee * Non-human primates * Transmission * Diagnostics Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine

  1. Wild chimpanzees are infected by Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Jirků, M.; Votýpka, J.; Petrželková, Klára Judita; Jirků-Pomajbíková, K.; Kriegová, E.; Vodička, R.; Lankester, F.; Leendertz, S. A. J.; Wittig, R. M.; Boesch, Ch.; Modrý, D.; Ayala, F. J.; Leendertz, F. H.; Lukeš, J.

    2015-01-01

    Roč. 4, č. 3 (2015), s. 277-282. ISSN 0020-7519 Institutional support: RVO:68081766 Keywords : Trypanosomes * Chimpanzee * Non-human primates * Transmission * Diagnostics Subject RIV: EG - Zoology Impact factor: 3.872, year: 2014

  2. 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.

  3. 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.

  4. Seismic isolation for Advanced LIGO

    International Nuclear Information System (INIS)

    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

  5. Isolated transfer of analog signals

    Science.gov (United States)

    Bezdek, T.

    1974-01-01

    Technique transfers analog signal levels across high isolation boundary without circuit performance being affected by magnetizing reactance or leakage inductance. Transfers of analog information across isolated boundary are made by interrupting signal flow, with switch, in such a manner as to produce alternating signal which is applied to transformer.

  6. Patients experience of source isolation

    DEFF Research Database (Denmark)

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

    2013-01-01

    , Nursing education in Århus, Hedeager 2, 8200 Aarhus N, Denmark. Background: Medical treatment and care of patients with infections may include source isolation of the patient, to avoid spreading of the infection. However, isolation is a potential physiological and psychological stress factor to the....... Quality of Care: The patients felt abandoned and forgotten by the nurses, because of fewer visits and time limited communication. This led to emotions such as frustrations, insecurity and neglect. While isolated the patients felt it difficult to achieve contact and have an optimal relation with the nurses...... experience both positive and negative effects of source isolation, and areas of potential interest for developing new strategies to improve care of isolated patients were identified. Surprisingly, despite both verbal and written information, the information has not been understood by the patients. Repetitive...

  7. 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.

  8. 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.

  9. Development of base isolated APWR

    International Nuclear Information System (INIS)

    The applicability of a seismic-isolation device to an Advanced Pressurized Water Reactor (APWR) plant was investigated in an attempt to rationally achieve plant safety against earthquake and promote the standardization of plant design. Consequently, it was found that the seismic-isolation device is capable of significantly mitigating the effects of seismic force on the building. As a result, in addition to a reduction in building volume, and wall thickness, the optimal design of support structures for equipment and piping can be achieved while maintaining safety against earthquakes. Finally, it has been verified that the base-isolated APWR plant will have an advantage in construction costs even after taking into account the costs of providing the seismic-isolation device. (author)

  10. 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.

  11. 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

  12. 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 ...

  13. CHARACTERIZATION OF RUBBER DEGRADING ISOLATES

    Directory of Open Access Journals (Sweden)

    M. D. Chengalroyen

    2012-12-01

    Full Text Available Sixteen soil samples were screened for the presence of rubber degrading strains. Twenty-five strains displaying clear zone formation on latex agar plates were purified. Identification revealed that twenty three of these isolates were Streptomyces species, one Pseudonocardia species and one Methylibium species. The addition of carbon sources with the exception of tween 80 enhanced extracellular rubber biodegradation. Scanning electron microscopy revealed that the isolates were able to colonize and penetrate vulcanized glove rubber.

  14. CHARACTERIZATION OF RUBBER DEGRADING ISOLATES

    OpenAIRE

    M. D. Chengalroyen; Dabbs, E R

    2012-01-01

    Sixteen soil samples were screened for the presence of rubber degrading strains. Twenty-five strains displaying clear zone formation on latex agar plates were purified. Identification revealed that twenty three of these isolates were Streptomyces species, one Pseudonocardia species and one Methylibium species. The addition of carbon sources with the exception of tween 80 enhanced extracellular rubber biodegradation. Scanning electron microscopy revealed that the isolates were able to colonize...

  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. 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.

  20. Solo doctors and ethical isolation.

    Science.gov (United States)

    Cooper, R J

    2009-11-01

    This paper uses the case of solo doctors to explore whether working in relative isolation from one's peers may be detrimental to ethical decision-making. Drawing upon the relevance of communication and interaction for ethical decision-making in the ethical theories of Habermas, Mead and Gadamer, it is argued that doctors benefit from ethical discussion with their peers and that solo practice may make this more difficult. The paper identifies a paucity of empirical research related to solo practice and ethics but draws upon more general medical ethics research and a study that identified ethical isolation among community pharmacists to support the theoretical claims made. The paper concludes by using the literary analogy of Soderberg's Doctor Glas to illustrate the issues raised and how ethical decision-making in relative isolation may be problematical. PMID:19880707

  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...... between R2 and R2-R3 sympathicotomy for isolated facial blushing. Both were effective, and QOL increased significantly. Despite very frequent side effects, the vast majority of patients were satisfied. Surprisingly, many patients experienced mild recurrent symptoms within the first year; this should...

  2. 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.

  3. Seismic, shock, and vibration isolation 1991

    International Nuclear Information System (INIS)

    It covers a wide variety of topics, including shock and vibration isolation analysis methods, development of new isolation system, characterization of material properties of vibration isolation components, analytical/experimental methods, optimal isolation design, and isolation system design criteria and requirements. The structures considered included buildings, high-tech facilities, nuclear power plants, and pipe lines. The work reported here is representative of current research activities and contributed to the advancement of the state of the art in vibration isolation. THe editor hopes this volume will serve as a useful resource for research and design engineers and stimulate further interest in seismic, shock, and vibration isolation research

  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. 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

  6. Completely Isolated? Health Information Seeking among Social Isolates

    Science.gov (United States)

    Askelson, Natoshia M.; Campo, Shelly; Carter, Knute D.

    2011-01-01

    To better target messages it is important to determine where people seek their health information. Interpersonal networks are a common way most people gather health information, but some people have limited networks. Using data from the 2004 General Social Survey (N = 984), we compared social isolates and nonisolates in their health…

  7. 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.

  8. 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...

  9. 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.

  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. Emotional isolation in BBC Forum

    Science.gov (United States)

    Sienkiewicz, J.; Chmiel, A.

    2014-03-01

    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.

  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. 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.

  16. Study on three dimensional seismic isolation system

    International Nuclear Information System (INIS)

    Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) launched joint research programs on structural design and three-dimensional seismic isolation technologies, as part of the supporting R and D activities for the feasibility studies on commercialized fast breeder reactor cycle systems. A research project by JAPC under the auspices of the Ministry of Economy, Trade, and Industry (METI) with technical support by JNC is included in this joint study. This report contains the results of the research on the three dimensional seismic isolation technology, and the results of this study are summarized in the following five aspects. (1) Study on Requirements for the Realization of 3-dimensional Base Isolation System. The simulated seismic wave 'case study S2', which was applied to the horizontal seismic isolation study for demonstrative FBR, was adopted applying to this study. Seismic response analyses of NPP building and R/V were conducted by this wave. The conditions required for the realization of 3-dimensional isolation system for FBR were clarified in terms of vertical frequency and damping ratio of the system, considering the design criteria for the core support plate etc. and their responses in acceleration and displacement. (2) Investigation and Clarification of 3-dimensional Isolation Concepts. Three types of seismic isolation system were examined on the feature of the isolation system, development status and problems to be solved. Then, six types of seismic isolation device were also investigated on the same aspects by literature. (3) Preliminary Evaluation of 3-dimensional Isolation Concepts. By preliminarily evaluating three types of seismic isolation system on easiness, effectiveness and cost of development, 3-dimensional entire building base isolation system and horizontal entire building base isolation system with vertically isolated for main equipments were selected for FBR. Then, air and dish springs were selected as

  17. 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

  18. Preparation of isolated carbon nanotubes

    International Nuclear Information System (INIS)

    Full text: Carbon nanotubes are of great interest for a large range of applications from physical chemistry, solid state physics to molecular quantum optics. We propose the preparation of molecular beams of isolated carbon nanotubes for future matter wave experiments, as well as for applications in the material sciences and spectroscopy. Carbon nanotubes may be particularly interesting for quantum experiments because of their low ionization threshold, high mechanical stability and high polarizability. This is expected to facilitate the cooling, coherent manipulation and efficient detection of such molecular beams. For this purpose we are investigating different methods of solvation, isolation and shortening of carbon nanotubes from commercial bundles. Length and diameter distributions are recorded by SPM whereas the unbundling of the tubes is determined by absorption spectroscopy. Established methods from physical chemistry, such as laser desorption are currently being modified and studied as potential tools for generating beams of nanotubes in the mass range of around 50.000-100.000 amu. (author)

  19. 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...

  20. Isolated tuberculosis of the sternum

    International Nuclear Information System (INIS)

    Isolated tuberculous foci of the sternum are rare. In a period of 26 years (1955 to 1981) we have treated ten sternal lesions surgically in our clinic. Eight of these were tuberculous. The clinical material (three females, five males) is described, including diagnostic and therapeutic details. The frequency, localisation, clinical features, diagnosis, treatment, prognosis and differential diagnosis of specific sternal infections are discussed and the relevant literature is reviewed. (orig.)

  1. Multipole moments of isolated horizons

    International Nuclear Information System (INIS)

    To every axi-symmetric isolated horizon we associate two sets of numbers, Mn and Jn with n = 0, 1, 2, ..., representing its mass and angular momentum multipoles. They provide a diffeomorphism invariant characterization of the horizon geometry. Physically, they can be thought of as the 'source multipoles' of black holes in equilibrium. These structures have a variety of potential applications ranging from equations of motion of black holes and numerical relativity to quantum gravity

  2. Customizable Isolation in Transactional Workflow

    OpenAIRE

    Guabtni, Adnene; Charoy, François; Godart, Claude

    2005-01-01

    In Workflow Management Systems (WFMSs) safety of execution is a main need of more and more business processes and transactional workflows are real needs inside enterprizes. In previous works, transactional models consider mainly atomicity as the main issue regarding long term transactions. It rarely consider the fact that many processes may run concurrently and thus access and update the same data. Usually, the main isolation item is the data on which we apply locking approaches and this atti...

  3. 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...

  4. 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...

  5. 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...

  6. 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.

  7. 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...

  8. 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...

  9. Genetics Home Reference: isolated hyperCKemia

    Science.gov (United States)

    ... the elevated blood levels of creatine kinase that characterize this condition. In addition to isolated hyperCKemia , CAV3 ... cause the disorder. In most cases, an affected person has one parent with isolated hyperCKemia or another ...

  10. Isolation of Cellulolytic Actinomycetes from Marine Sediments

    OpenAIRE

    Veiga, Manuel; Esparis, Azucena; Fabregas, Jaime

    1983-01-01

    The cellulolytic activity of 36 actinomycetes strains isolated from marine sediments was investigated by the cellulose-azure method. Approximately 50% of the isolates exhibited various degrees of cellulolytic activity.

  11. 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....

  12. Isolation of haloorganic groundwater humic substances

    DEFF Research Database (Denmark)

    Krog, M.; Grøn, C.

    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 was...

  13. Molecular characterization of Danish Cryptosporidium parvum isolates

    DEFF Research Database (Denmark)

    Enemark, Heidi L.; Ahrens, Peter; Juel, Cynthia Dawn;

    2002-01-01

    characterized as C. meleagridis. The porcine Cryptosporidium isolates (N = 4) revealed a pattern which was genetically distinct from human and bovine isolates. Cryptosporidium in a hedgehog (Erinaceus europaeus L.) was identified for the first time. By microsatellite sequencing the hedgehog isolate showed a...

  14. 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.

  15. [Isolation of proteins in coconut water].

    Science.gov (United States)

    Birosel, D M; de Oliveira Ferro, V; Holcberg, I B; Pitelli, A C

    1976-01-01

    The isolation of protein fractions in cocont water was achieved by precipitation with controlled pH variation obtaining three isolates at pH 8,5, 10,5, and 11,5. By comparing each of these isolates with proteins of coconut milk, a similarity between properties of the first two isolates of the water - pH 8,5, 10,5--and those of coconut serum proteins -- glutelin and prolamin was observed. The third isolate is entirely absent from the milk, when coconut water is not used in the second pressing to obtain the milk. PMID:19819

  16. 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.

  17. 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.

  18. 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

  19. [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

  20. Basalt waste isolation project overview

    International Nuclear Information System (INIS)

    The proposed candidate site for a high-level nuclear waste repository is located beneath the Hanford Nuclear Reservation in southeastern Washington State. At this point, the Hanford Reservation has been selected as one of three preferred candidates in the draft environmental assessment. Project activities have concentrated on understanding the site location with respect to the 10CFR60, 40CFR191, and 10CFR960, identifying critical parameters for design of water package and repository seals, and identifying parameters for repository design. This paper describes the program to evaluate the site and to identify the natural processes that would effect isolation

  1. Marchantin A, a macrocyclic bisbibenzyl ether, isolated from the liverwort Marchantia polymorpha, inhibits protozoal growth in vitro

    DEFF Research Database (Denmark)

    Jensen, Sophie; Omarsdottir, Sesselja; Bwalya, Angela Gono;

    2012-01-01

    proliferation of the Plasmodium falciparum strains, NF54 (IC(50)=3.41µM) and K1 (IC(50)=2.02µM) and showed activity against other protozoan species Trypanosoma brucei rhodesiense, T. cruzi and Leishmania donovani with IC(50) values 2.09, 14.90 and 1.59µM, respectively. Marchantin A was tested against three...

  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. 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

  4. 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...

  5. 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...

  6. 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...

  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. Isolation of chloroplastic phosphoglycerate kinase

    Energy Technology Data Exchange (ETDEWEB)

    Macioszek, J.; Anderson, L.E. (Univ. of Illinois, Chicago (USA)); Anderson, J.B. (Pennsylvania State Univ., University Park (USA))

    1990-09-01

    We report here a method for the isolation of high specific activity phosphoglycerate kinase (EC 2.7.2.3) from chloroplasts. The enzyme has been purified over 200-fold from pea (Pisum sativum L.) stromal extracts to apparent homogeneity with 23% recovery. Negative cooperativity is observed with the two enzyme phosphoglycerate kinase/glyceraldehyde-3-P dehydrogenase (EC 1.2.1.13) couple restored from the purified enzymes when NADPH is the reducing pyridine nucleotide, consistent with earlier results obtained with crude chloroplastic extracts. Michaelis Menten kinetics are observed when 3-phosphoglycerate is held constant and phosphoglycerate kinase is varied, which suggests that phosphoglycerate kinase-bound 1,3-bisphosphoglycerate may be the preferred substrate for glyceraldehyde-3-P dehydrogenase in the chloroplast.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Radiation tolerant isolation amplifiers for temperature measurement

    International Nuclear Information System (INIS)

    This paper concentrates on the selection of radiation tolerant isolation amplifiers, which are suitable for the signal conditioners for cryogenic system in the Large Hadron Collider (LHC). The evolution and the results of different commercial isolation amplifiers' parameters under neutron and gamma radiation are presented. In most cases, the tested isolation amplifiers' input offset voltage, bias currents and output offset voltage hardly changed during the radiation. The DC gain in input stage was only affected for some isolation amplifiers with a small open loop gain. Transmission coefficient showed decrease for all the tested isolation amplifiers. Also, the DC output voltage increased and the ripple voltage decreased for all the build-in isolated regulators. In addition, results on 1B41 signal conditioner showed that it was tolerant to 7-8x1012 n/cm2, which was 50% higher than the expected dose in the LHC

  14. Tsetse ecology in a Liberian rain-forest focus of Gambian sleeping sickness.

    Science.gov (United States)

    Kaminsky, R

    1987-07-01

    Investigations on tsetse ecology were undertaken in Bong County of Liberia during the dry season, October 1981 to February 1982, around villages where the human infection rate with Trypanosoma brucei gambiense Dutton was about 2%. Most tsetse captured in biconical traps were Glossina palpalis Robineau-Desvoidy and G. pallicera Bigot, with relatively few G. fusca Walker and G. nigrofusca Newstead. Swamps and water-gathering places were predominant habitats of all four species, but tsetse were also found in coffee and cocoa plantations. Breeding-places of G. palpalis were found in the leaf axils of oilpalm trees (Elaeis guineensis Jacquin), especially beside paths where people would risk being bitten. Bloodmeals of twenty-nine wild-caught G. palpalis were identified as mostly from man (fifteen) and bushbuck (Tragelaphus scriptus (Pallas] or other wild ruminants (eleven), plus three from reptiles. It is concluded that man may be the principal host of tsetse in the area, while man or bushbuck could be the main reservoir to T.b. gambiense infection. Most of the activity of G. palpalis occurs in the early afternoon from noon to 16.00 hours. Mean life-span of G. palpalis and G. pallicera, estimated from wing-fray age-groups, was consistent with the females, and to a lesser degree the males, having vector potential. PMID:2979539

  15. 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...

  16. Isolation of Circulating Tumor Cells by Dielectrophoresis

    OpenAIRE

    Gascoyne, Peter R.C.; Sangjo Shim

    2014-01-01

    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...

  17. 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...

  18. 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.

  19. Klebsiella pneumoniae KPC: first isolations in Italy

    OpenAIRE

    Carla Fontana; Marco Favaro; Loredana Sarmati; Silvia Natoli; Anna Altieri; Maria Cristina Bossa; Silvia Minelli; Cartesio Favalli

    2009-01-01

    Klebsiella pneumoniae carbapenemase (KPC) was detected in two isolates of carbapenem-resistant K. pneumoniae in an italian teaching hospital. This is the first report of a KPC-producing isolates in our country. The first strain was isolated from a urine sample collected from a indwelling urinary catheter in a ICU-patient with subdural haematoma, while the second was from the culture of the central venous catheter (CVC) in a patient affected by Crohn’s disease admitted in gastroenterology ward...

  20. 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.

  1. 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.

  2. Permanent isolation surface barrier: Functional performance

    International Nuclear Information System (INIS)

    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

  3. 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

  4. Recent advances in nonlinear passive vibration isolators

    Science.gov (United States)

    Ibrahim, R. A.

    2008-07-01

    The theory of nonlinear vibration isolation has witnessed significant developments due to pressing demands for the protection of structural installations, nuclear reactors, mechanical components, and sensitive instruments from earthquake ground motion, shocks, and impact loads. In view of these demands, engineers and physicists have developed different types of nonlinear vibration isolators. This article presents a comprehensive assessment of recent developments of nonlinear isolators in the absence of active control means. It does not deal with other means of linear or nonlinear vibration absorbers. It begins with the basic concept and features of nonlinear isolators and inherent nonlinear phenomena. Specific types of nonlinear isolators are then discussed, including ultra-low-frequency isolators. For vertical vibration isolation, the treatment of the Euler spring isolator is based on the post-buckling dynamic characteristics of the column elastica and axial stiffness. Exact and approximate analyses of axial stiffness of the post-buckled Euler beam are outlined. Different techniques of reducing the resonant frequency of the isolator are described. Another group is based on the Gospodnetic-Frisch-Fay beam, which is free to slide on two supports. The restoring force of this beam resembles to a great extent the restoring roll moment of biased ships. The base isolation of buildings, bridges, and liquid storage tanks subjected to earthquake ground motion is then described. Base isolation utilizes friction elements, laminated-rubber bearings, and the friction pendulum. Nonlinear viscoelastic and composite material springs, and smart material elements are described in terms of material mechanical characteristics and the dependence of their transmissibility on temperature and excitation amplitude. The article is closed by conclusions, which highlight resolved and unresolved problems and recommendations for future research directions.

  5. 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...

  6. 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

  7. Cooling device upon reactor isolation

    International Nuclear Information System (INIS)

    A vacuum breaking valve is disposed to a sucking pipeline of vacuum pumps. A sucking port of the breaking valve is connected with an exhaustion side of a relief valve of a liquid nitrogen-filled tank by way of communication pipes. When a cooling device is operated upon reactor isolation and the vacuum pumps are operated, a three directional electromagnetic valve is operated, and nitrogen discharged out of the exhaustion port of the relief valve of the liquid nitrogen-filled tank is sent to a nitrogen releasing port on the suction side of the vacuum breaking valve by way of the communication pipes and released to atmosphere. When the pressure in the vacuum tank is excessively lowered in this state and the vacuum breaking valve is opened, nitrogen flows from the nitrogen discharge port into the vacuum tank through the breaking valve, and are sent to a pressure suppression chamber by the vacuum pumps. Since a great amount of nitrogen is sent to the pressure suppression chamber, and the inflow of the air is reduced, increase of oxygen concentration in the pressure suppression chamber can be suppressed. (I.N.)

  8. Isolation of Plasmid DNA from Butyrivibrio fibrisolvens†

    OpenAIRE

    Teather, Ronald M.

    1982-01-01

    A procedure based on successive precipitation of cell lysates with sodium dodecyl sulfate-NaCl and polyethylene glycol 6000 was developed which allows the isolation of plasmid DNA from Butyrivibrio fibrisolvens. A survey of B. fibrisolvens strains isolated from the bovine rumen showed that plasmids are a common feature of this species.

  9. 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...

  10. 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.

  11. 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 is not a...

  12. 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).

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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...

  19. Study on three dimensional seismic isolation system

    International Nuclear Information System (INIS)

    Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) launched joint research programs on structural design and three-dimensional seismic isolation technologies, as part of the supporting R and D activities for the feasibility studies on commercialized fast breeder reactor cycle systems. A research project by JAPC under the auspices of the Ministry of Economy, Trade, and Industry (METI) with technical support by JNC is included in this joint study. This report contains the results of the research on the three-dimensional seismic isolation technologies, and the results of this year's study are summarized in the following five aspects. (1) Study on Earthquake Condition for Developing 3-dimensional Base Isolation System. The case study S2 is one of the maximum ground motions, of which the records were investigated up to this time. But a few observed near the fault exceed the case study S2 in the long period domain, depending on the fault length and conditions. Generally it is appropriate that the response spectra ratio (vertical/horizontal) is 0.6. (2) Performance Requirement for 3-dimensional Base Isolation System and Devices. Although the integrity map of main equipment/piping dominate the design criteria for the 3-dimensional base isolation system, the combined integrity map is the same as those of FY 2000, which are under fv=1Hz and over hv=20%. (3) Developing Targets and Schedule for 3-dimensional Isolation Technology. The target items for 3-dimensional base isolation system were rearranged into a table, and developing items to be examined concerning the device were also adjusted. A development plan until FY 2009 was made from the viewpoint of realization and establishment of a design guideline on 3-dimensional base isolation system. (4) Study on 3-dimensional Entire Building Base Isolation System. Three ideas among six ideas that had been proposed in FY2001, i.e., '3-dimensional base isolation system incorporating hydraulic

  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. 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

  2. EMPLACEMENT DRIFT ISOLATION DOOR CONTROL SYSTEM

    International Nuclear Information System (INIS)

    The purpose of this analysis is to review and refine key design concepts related to the control system presently under consideration for remotely operating the emplacement drift isolation doors at the potential subsurface nuclear waste repository at Yucca Mountain. This analysis will discuss the key design concepts of the control system that may be utilized for remotely monitoring, opening, and closing the emplacement drift isolation doors. The scope and primary objectives of this analysis are to: (1) Discuss the purpose and function of the isolation doors (Presented in Section 7.1). (2) Review the construction of the isolation door and other physical characteristics of the doors that the control system will interface with (Presented in Section 7.2). (3) Discuss monitoring and controlling the operation of the isolation doors with a digital control system (either a Programmable Logic Controller (PLC) system or a Distributed Control System (DCS)) (Presented in Section 7.3). (4) Discuss how all isolation doors can be monitored and controlled from a subsurface central control center (Presented in Section 7.4). This analysis will focus on the development of input/output (I/O) counts including the types of I/O, redundancy and fault tolerance considerations, and processor requirements for the isolation door control system. Attention will be placed on operability, maintainability, and reliability issues for the system operating in the subsurface environment with exposure to high temperatures and radiation

  3. Seismic isolation of nuclear power plants

    International Nuclear Information System (INIS)

    Seismic isolation is a viable strategy for protecting safety-related nuclear structures from the effects of moderate to severe earthquake shaking. Although seismic isolation has been deployed in nuclear structures in France and South Africa, it has not seen widespread use because of limited new build nuclear construction in the past 30 years and a lack of guidelines, codes and standards for the analysis, design and construction of isolation systems specific to nuclear structures. The funding by the United States Nuclear Regulatory Commission of a research project to the Lawrence Berkeley National Laboratory and MCEER/University at Buffalo facilitated the writing of a soon-to-be-published NUREG on seismic isolation. Funding of MCEER by the National Science Foundation led to research products that provide the technical basis for a new section in ASCE Standard 4 on the seismic isolation of safety-related nuclear facilities. The performance expectations identified in the NUREG and ASCE 4 for seismic isolation systems, and superstructures and substructures are described in the paper. Robust numerical models capable of capturing isolator behaviors under extreme loadings, which have been verified and validated following ASME protocols, and implemented in the open source code OpenSees, are introduced.

  4. 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.

  5. 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.

  6. 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.

  7. Nonlinear vibration isolator with adjustable restoring force

    Science.gov (United States)

    Araki, Yoshikazu; Asai, Takehiko; Kimura, Kosuke; Maezawa, Kosei; Masui, Takeshi

    2013-11-01

    This paper presents a vertical quasi-zero stiffness (QZS) vibration isolator with a mechanism for adjusting restoring force. QZS vibration isolators have high initial stiffness and QZS around the static equilibrium position. This way, excessive deformation due to self-weight can be avoided while having enough vibration reduction capability to dynamic excitations. One of the main issues left for QZS vibration isolators is the difficulty in keeping the vibration reduction capability when the vibration isolated object is replaced. In such a case, adjustment of its restoring force becomes necessary in accordance with the self-weight of the newly placed vibration isolated object. This paper attempts to address this issue by proposing a mechanism that enables quick and easy adjustment of the restoring force of a QZS vibration isolator. The proposed mechanism consists of cranks and a screw jack. With the present mechanism, the restoring force provided by horizontally placed springs can be converted into the vertical restoring force of the vibration isolator. In the conversion, the vertical resisting force can be adjusted simply by applying and removing torque to the screw jack to change and hold the angle of inclined bars placed in the cranks. In this study, a prototype of a class of QZS vibration isolator having the proposed mechanism is produced. Shaking table tests are performed to demonstrate the efficacy of the present mechanism, where the produced prototype is subjected to various sinusoidal and earthquake ground motions. It is demonstrated through the shaking table tests that the produced prototype can reduce the response acceleration within the same tolerance even when the mass of the vibration isolated object is changed.

  8. Molecular characterization of Korean rabies virus isolates

    OpenAIRE

    Yang, Dong-Kun; Park, Young-nam; Hong, Gyeong-Soo; Kang, Hee-Kyung; Oh, Yoon-I; Cho, Soo-Dong; SONG, Jae-Young

    2011-01-01

    The nucleoprotein (N) and glycoprotein (G) of 11 Korean rabies virus (RABV) isolates collected from animals diagnosed with rabies between 2008 and 2009 were subjected to molecular and phylogenetic analyses. Six isolates originated from domestic animals (cattle and dogs) and five were obtained from wild free-ranging raccoon dogs. The similarities in the nucleotide sequences of the N gene among all Korean isolates ranged from 98.1 to 99.8%, while those of the G gene ranged from 97.9 to 99.3%. B...

  9. STREPTOMYCETE Producing Antibiotics Isolated From Egyptian Soil

    International Nuclear Information System (INIS)

    An investigation was concerned the distribution of Streptomyces species in some types of Egyptian soils. Thirty nine actinomycetes isolates were obtained from 7 types of Egyptian soils; 8 isolates exhibited antimicrobial activities against all tested organisms and three of them were identified as Streptomyces griseoluteus (YM23), Streptomyces aurantiogriseus (S15) and Streptomyces nogalator (H12). RAPD-PCR showed correlation between 8 isolates in 3 clades. The active metabolite was extracted with ethyl acetate and concentrated in vacuum and the crude fraction was purified using thin layer and column chromatography

  10. Isolation and distribution of rabbit keratocyte precursors

    OpenAIRE

    Mimura, Tatsuya; Amano, Shiro; Yokoo, Seiichi; Uchida, Saiko; Usui, Tomohiko; Yamagami, Satoru

    2008-01-01

    Purpose To isolate multipotent precursors from the rabbit corneal stroma and to compare the distribution and proliferative capacity of keratocyte precursors obtained from the central and peripheral regions of the corneal stroma. Methods The rabbit corneal stroma was divided into a peripheral region (6.0–10.0 mm in diameter) and a central region (6.0 mm in diameter). A sphere-forming assay was then performed to isolate precursors from the stroma of each region. To promote differentiation, isol...

  11. 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....

  12. 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

  13. Lonely, Isolated People May Be Prone to Heart Disease, Stroke

    Science.gov (United States)

    ... Isolated People May Be Prone to Heart Disease, Stroke Study found social isolation raised the risk by ... face a higher risk of heart disease and stroke, researchers report. Social isolation raised that risk by ...

  14. 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.

  15. 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

  16. 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...

  17. 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.

  18. 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...

  19. Genetics Home Reference: isolated ectopia lentis

    Science.gov (United States)

    ... isolated ectopia lentis . Affected individuals often have nearsightedness (myopia) and can have an irregular curvature of the lens or a structure that covers the front of the eye (the cornea), which causes blurred vision (astigmatism). They may also develop clouding ...

  20. Extracellular enzymes of Fusarium graminearum isolates

    Directory of Open Access Journals (Sweden)

    Gisele Eleonora Kikot

    2010-08-01

    Full Text Available Fusarium graminearum isolates from three different agroecological regions in Argentina were examined according to the production of different extracellular enzyme activities of potential biotechnological interest: pectinases (PGase: polygalacturonase and PMGase: polymethylgalacturonase, cellulase (CMCase: carboxymethylcellulase and hemicellulase (xylanase. The isolates were grown in minimum salt medium supplemented with 0.25% glucose, 0.125% citric pectin and 0.125% oat bran as carbon sources and/or enzyme inducers. PGase activity was detected early (after two days of incubation in all the cultures; it was found to be the highest for all the isolates. PMGase was high only for those isolates of the II region. CMCase and endoxylanase activities were particularly found at late stages (after four and seven days of incubation, respectively and the maximum values were lower than pectinase activities.

  1. 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...

  2. In-vacuum Faraday isolation remote tuning.

    Science.gov (United States)

    Accadia, T; Acernese, F; Antonucci, F; Aoudia, S; Arun, K G; Astone, P; Ballardin, G; Barone, F; Barsuglia, M; Bauer, Th S; Beker, M G; Bigotta, S; Birindelli, S; Bitossi, M; Bizouard, M A; Blom, M; Boccara, C; Bondu, F; Bonelli, L; Bosi, L; Braccini, S; Bradaschia, C; Brillet, A; Brisson; Budzynski, R; Bulik, T; Bulten, H J; Buskulic, D; Cagnoli, G; Calloni, E; Campagna, E; Canuel, B; Carbognani, F; Cavalier, F; Cavalieri, R; Cella, G; Cesarini, E; Chassande-Mottin, E; Chincarini, A; Cleva, F; Coccia, E; Colacino, C N; Colas, J; Colla, A; Colombini, M; Corda, C; Corsi, A; Coulon, J-P; Cuoco, E; D'Antonio, S; Dari, A; Dattilo, V; Davier, M; Day, R; De Rosa, R; del Prete, M; Di Fiore, L; Di Lieto, A; Emilio, M Di Paolo; Di Virgilio, A; Dietz, A; Drago, M; Fafone, V; Ferrante, I; Fidecaro, F; Fiori, I; Flaminio, R; Fournier, J-D; Franc, J; Frasca, S; Frasconi, F; Freise, A; Gammaitoni, L; Garufi, F; Gemme, G; Genin, E; Gennai, A; Giazotto, A; Gouaty, R; Granata, M; Greverie, C; Guidi, G M; Heitmann, H; Hello, P; Hild, S; Huet, D; Jaranowski, P; Kowalska, I; Królak, A; La Penna, P; Leroy, N; Letendre, N; Li, T G F; Lorenzini, M; Loriette, V; Losurdo, G; Mackowski, J M; Majorana, E; Man, N; Mantovani, M; Marchesoni, F; Marion, F; Marque, J; Martelli, F; Masserot, A; Michel, C; Milano, L; Minenkov, Y; Mohan, M; Moreau, J; Morgado, N; Morgia, A; Mosca, S; Moscatelli, V; Mours, B; Neri, I; Nocera, F; Pagliaroli, G; Palladino, L; Palomba, C; Paoletti, F; Pardi, S; Parisi, M; Pasqualetti, A; Passaquieti, R; Passuello, D; Persichetti, G; Pichot, M; Piergiovanni, F; Pietka, M; Pinard, L; Poggiani, R; Prato, M; Prodi, G A; Punturo, M; Puppo, P; Rabaste, O; Rabeling, D S; Rapagnani, P; Re, V; Regimbau, T; Ricci, F; Robinet, F; Rocchi, A; Rolland, L; Romano, R; Rosińska, D; Ruggi, P; Sassolas, B; Sentenac, D; Sturani, R; Swinkels, B; Toncelli, A; Tonelli, M; Tournefier, E; Travasso, F; Trummer, J; Vajentei, G; van den Brand, J F J; van der Putten, S; Vavoulidis, M; Vedovato, G; Verkindt, D; Vetrano, F; Viceré, A; Vinet, J-Y; Vocca, H; Was, M; Yvert, M

    2010-09-01

    In-vacuum Faraday isolators (FIs) are used in gravitational wave interferometers to prevent the disturbance caused by light reflected back to the input port from the interferometer itself. The efficiency of the optical isolation is becoming more critical with the increase of laser input power. An in-vacuum FI, used in a gravitational wave experiment (Virgo), has a 20 mm clear aperture and is illuminated by an almost 20 W incoming beam, having a diameter of about 5 mm. When going in vacuum at 10(-6) mbar, a degradation of the isolation exceeding 10 dB was observed. A remotely controlled system using a motorized lambda=2 waveplate inserted between the first polarizer and the Faraday rotator has proven its capability to restore the optical isolation to a value close to the one set up in air. PMID:20842804

  3. Antigenic typing Polish isolates of canine parvovirus

    International Nuclear Information System (INIS)

    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

  4. Isolated Enteric Cyst in the Neck

    OpenAIRE

    Amit Mahore; Raghvendra Ramdasi; Palak Popat; Shilpa Sankhe; Vishakha Tikeykar

    2014-01-01

    We report an extremely rare case of isolated enteric cyst in the neck region which was diagnosed on the histopathological examination. It was suspected to be duplication cyst on radiology. We have also evaluated the differential diagnosis and management issues.

  5. 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.

  6. Collection, Isolation and Culture of Marine Algae.

    Science.gov (United States)

    James, Daniel E.

    1984-01-01

    Methods of collecting, isolating, and culturing microscopic and macroscopic marine algae are described. Three different culture media list of chemicals needed and procedures for preparing Erdschreiber's and Provasoli's E. S. media. (BC)

  7. 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...

  8. 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...

  9. Standardization of Islet Isolation and Transplantation Variables

    OpenAIRE

    Friberg, Andrew S

    2011-01-01

    Currently, the transplantation of islets of Langerhans is a viable means to maintain control of blood sugar levels and reduce the risk of hypoglycemia in defined populations with brittle type I diabetes mellitus or those requiring pancreatectomy. However, the process of islet isolation is highly variable and not all isolations result in islet numbers or quality suitable for transplantation. This thesis aimed to improve transplantation success through optimization and standardization of the is...

  10. Isolation of Saprophytic Basidiomycetes from Soil

    OpenAIRE

    Thorn, R.G.; Reddy, C. A.; Harris, D.; Paul, E. A.

    1996-01-01

    A method with the combined advantages of soil particle washing, selective inhibitors, and an indicator substrate was developed to isolate saprophytic basidiomycetes from soil. Organic particles were washed from soil and plated on a medium containing lignin, guaiacol, and benomyl, which reduced mold growth and allowed detection of basidiomycetes producing laccase or peroxidase. The 64 soil samples yielded 67 basidiomycete isolates, representing 51 groups on the basis of morphology and physiolo...

  11. 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.

  12. 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 ...

  13. 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

  14. 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...

  15. 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...

  16. 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).

  17. 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.

  18. 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...

  19. Base isolation strategies for structures and components

    International Nuclear Information System (INIS)

    In the present report the effect of laminated rubber bearing (LRB) system on the dynamic response of the structure was studied. A LRB system was designed and tested in the laboratory for its dynamic characteristics. Finite element analysis was also performed and based on this analysis, isolator for PHWR nuclear power plant was designed. Analysis of the building was performed with and without isolator. Comparison of responses was made in terms of frequencies, accelerations and displacements and floor response spectra. (author)

  20. ISOLATION OF RUTIN FROM PHYLLANTHUS AMARUS

    OpenAIRE

    Prabodh Shukla et al.

    2012-01-01

    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...

  1. Extracellular enzymes of Fusarium graminearum isolates

    OpenAIRE

    Gisele Eleonora Kikot; Roque Alberto Hours; Teresa María Alconada

    2010-01-01

    Fusarium graminearum isolates from three different agroecological regions in Argentina were examined according to the production of different extracellular enzyme activities of potential biotechnological interest: pectinases (PGase: polygalacturonase and PMGase: polymethylgalacturonase), cellulase (CMCase: carboxymethylcellulase) and hemicellulase (xylanase). The isolates were grown in minimum salt medium supplemented with 0.25% glucose, 0.125% citric pectin and 0.125% oat bran as carbon sour...

  2. 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 ...

  3. 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....

  4. Using Euler buckling springs for vibration isolation

    CERN Document Server

    Winterflood, J; Blair, D G

    2002-01-01

    Difficulties in obtaining ideal vertical vibration isolation with mechanical springs are identified as being due to the mass of the elastic element which is in turn due to its energy storage requirement. A new technique to minimize this energy is presented - being an Euler column undergoing elastic buckling. The design of a high performance vertical vibration isolation stage based on this technique is presented together with its measured performance.

  5. Using Euler buckling springs for vibration isolation

    International Nuclear Information System (INIS)

    Difficulties in obtaining ideal vertical vibration isolation with mechanical springs are identified as being due to the mass of the elastic element which is in turn due to its energy storage requirement. A new technique to minimize this energy is presented - being an Euler column undergoing elastic buckling. The design of a high performance vertical vibration isolation stage based on this technique is presented together with its measured performance

  6. Microsample preparation by dielectrophoresis: isolation of malaria

    OpenAIRE

    Gascoyne, Peter; Mahidol, Chulabhorn; Ruchirawat, Mathuros; Satayavivad, Jutamaad; WATCHARASIT, PIYAJIT; Becker, Frederick F.

    2002-01-01

    An important enabling factor for realising integrated micro fluidic analysis instruments for medical diagnostics purposes is front-end sample preparation. Dielectrophoresis is a method that offers great potential for cell discrimination and isolation for sample processing, and here we have applied it to the problem of isolating malaria-infected cells from blood. During development of the malarial pathogen, Plasmodium falciparum, increases occur in the ionic permeability of the plasma membrane...

  7. 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...

  8. Xerophilic mycopopulations isolated from rapeseeds (Brassica napus

    Directory of Open Access Journals (Sweden)

    Škrinjar Marija M.

    2013-01-01

    Full Text Available This paper presents the results of an investigation related to mycological populations of rapeseed samples produced in the Institute of Field and Vegetable Crops in Novi Sad (location: Rimski Šančevi, Novi Sad, with a special emphasis on the potentially toxigenic mycopopulations. Mycological investigations were performed on the samples that were treated with 4% solution of Na-hypochlorite, and on the ones that were not submitted to this treatment. Isolation and determination of total mould count was carried out using Dichloran Glycerol Agar (DG18. The identification of isolated moulds was done according to modern keys for fungal determination. From 20 untreated tested samples, 17 were contaminated with moulds (10.0 to 4.7x102 cfu/g. When the samples were treated with 4% solution of Na-hypochlorite, moulds were isolated only form 4 samples, and the total mould count ranged from 10.0 to 60.0 cfu/g. In the isolated mycopopulations, xerophilic moulds dominated, especially those from the genera Aspergillus, Eurotium and Penicillium. In the isolated mycopopulations, high degree of isolated species belonged to toxigenic species from the genera Alternaria, Aspergillus, Fusarium, Eurotium and Penicillium. [Projekat Ministarstva nauke Republike Srbije, br. III46009 i br.TR31025

  9. 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.

  10. 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...

  11. Control issues of microgravity vibration isolation

    Science.gov (United States)

    Knospe, C. R.; Hampton, R. D.; Allaire, P. E.

    1991-01-01

    Active vibration isolation systems contemplated for microgravity space experiments may be designed to reach given performance requirements in a variety of ways. An analogy to passive isolation systems proves to be illustrative but lacks the flexibility as a design tool of a control systems approach and may lead to poor designs. For example, it is shown that a focus on equivalent stiffness in isolation system design leads to a controller that sacrifices robustness for performance. Control theory as applied to vibration isolation is reviewed and passive analogies are discussed. The loop shaping trade-off is introduced and used to design a single-degree-of-freedom fedback controller. An algebraic control design methodology is contrasted to loop shaping and critiqued. Multi-axis vibration isolation and the problems of decoupled single loop control are introduced through a two-degree-of-freedom example problem. It is shown that center of mass uncertainty may result in instability when decoupled single loop control is used. This results from the ill-conditioned nature of the feedback control design. The use of the Linear Quadratic Regulator synthesis procedure for vibration isolation controller design is discussed.

  12. 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.

  13. Isolated elliptical galaxies in the local Universe

    Science.gov (United States)

    Lacerna, I.; Hernández-Toledo, H. M.; Avila-Reese, V.; Abonza-Sane, J.; del Olmo, A.

    2016-04-01

    Context. We have studied a sample of 89 very isolated, elliptical galaxies at z color, specific star formation rate, galaxy size, and stellar age, as a function of stellar mass and environment based on SDSS data. We analyzed the blue and star-forming isolated ellipticals in more detail, through photometric characterization using GALFIT, and infer their star formation history using STARLIGHT. Results: 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 quenched. There are four isolated galaxies (≈4.5%) that are blue and star forming at the same time. These galaxies, with masses between 7 × 109 and 2 × 1010 h-2 M⊙, are also the youngest galaxies with light-weighted stellar ages ≲1 Gyr and exhibit bluer colors toward the galaxy center. Around 30-60% of their present-day luminosity, but only <5% of their present-day mass, is due to star formation in the last 1 Gyr. Conclusions: The processes of morphological transformation and quenching seem to be in general independent of environment since most of elliptical galaxies are "red and dead", although the transition to the red sequence should be faster for isolated ellipticals. In some cases, the isolated environment seems to propitiate the rejuvenation of ellipticals by recent (<1 Gyr) cold gas accretion.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Procedure for isolating the endophyte from tall fescue and screening isolates for ergot alkaloids.

    OpenAIRE

    Bacon, C W

    1988-01-01

    A procedure was developed to isolate and determine ergot alkaloid production by Acremonium coenophialum, the endophytic fungus of tall fescue. The procedure established that macerated leaf sheath or pith from inflorescence stem placed either in a liquid medium or on a corn meal-malt extract agar medium produced isolated mycelium and characteristic conidia within a 3- to 3.5-week period. Once isolated, each fungus was placed in another liquid medium, M104T, where competent strains produced tot...

  19. 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...

  20. 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...

  1. 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.

  2. 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.

  3. A Seismic Isolation Device Test for the evaluation of Performance Criteria of Seismic Isolated NPPs

    International Nuclear Information System (INIS)

    Seismic safety of NPP is one of the most important issues in a nuclear field after great east Japan earthquake in 2011. For the improvement of seismic safety of nuclear power plant, a seismic isolation is the easiest solution for increasing the seismic safety. Otherwise, the application of seismic isolation devices for nuclear power plants doesn't make the seismic risk of NPP increases always. According to the applying seismic isolation systems in NPPs, an acceleration response can be decreased but the relative displacement might be increased. Also the performance of isolation system is one of the most important parts of application of isolation system In this study, seismic isolation device tests were performed for the evaluation of performance criteria of isolation system. There are two kinds of tests were performed as below; Basic mechanical property test, Dynamic performance test In this study, seismic isolation device tests were performed for the evaluation of performance criteria of isolation system. Through this test, it can be recognized that in the case of considering a mechanical property test, dynamic and multi degree of loading conditions should be determined. But these differences should be examined how much affect to the global structural behavior

  4. 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

  5. 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.

  6. [Antioxidant activity of cationic whey protein isolate].

    Science.gov (United States)

    titova, M E; Komolov, S A; Tikhomirova, N A

    2012-01-01

    The process of lipid peroxidation (LPO) in biological membranes of cells is carried out by free radical mechanism, a feature of which is the interaction of radicals with other molecules. In this work we investigated the antioxidant activity of cationic whey protein isolate, obtained by the cation-exchange chromatography on KM-cellulose from raw cow's milk, in vitro and in vivo. In biological liquids, which are milk, blood serum, fetal fluids, contains a complex of biologically active substances with a unique multifunctional properties, and which are carrying out a protective, antimicrobial, regenerating, antioxidant, immunomodulatory, regulatory and others functions. Contents of the isolate were determined electrophoretically and by its biological activity. Cationic whey protein isolate included lactoperoxidase, lactoferrin, pancreatic RNase, lysozyme and angeogenin. The given isolate significantly has an antioxidant effect in model experimental systems in vitro and therefore may be considered as a factor that can adjust the intensity of lipid oxidation. In model solutions products of lipid oxidation were obtained by oxidation of phosphatidylcholine by hydrogen peroxide in the presence of a source of iron. The composition of the reaction mixture: 0,4 mM H2O2; 50 mcM of hemin; 2 mg/ml L-alpha-phosphatidylcholine from soybean (Sigma, German). Lipid peroxidation products were formed during the incubation of the reaction mixture for two hours at 37 degrees C. In our studies rats in the adaptation period immediately after isolation from the nest obtained from food given orally native cationic whey protein isolate at the concentration three times higher than in fresh cow's milk. On the manifestation of the antioxidant activity of cationic whey protein isolate in vivo evidence decrease of lipid peroxidation products concentration in the blood of rats from the experimental group receipt whey protein isolate in dos 0,6 mg/g for more than 20% (pwhey protein isolate has an

  7. 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.

  8. 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

  9. Entomopathogenicity of Simplicillium lanosoniveum Isolated in Korea.

    Science.gov (United States)

    Lim, Sung Yeol; Lee, Sehee; Kong, Hyun Gi; Lee, Jungkwan

    2014-12-01

    Fruiting bodies similar to those of the ascomycete fungi Podostroma cornu-damae and Cordyceps militaris were collected from Mt. Seunghak in Busan, Korea on August 21, 2012. The fruiting bodies were cylindrical, with tapered ends and golden red in color. The fruiting bodies contained abundant conidiophores bearing single-celled conidia, but no perithecia or asci. Pure culture of the fungal isolates was obtained through single-spore isolation. Analyses of morphological characteristics, including conidia shape, and phylogenetic traits, using internal transcribed spacer sequences, showed that these isolates belonged to the species Simplicillium lanosoniveum. Although this fungal species is known to be mycoparasitic, the isolates obtained in this study were unable to infect fungi. However, silkworms (Bombyx mori) inoculated with the fungal isolates died during the larval or pupal stages, as has been shown for the strongly entomopathogenic fungus Beauveria bassiana. This study is the first report of the entomopathogenicity of S. lanosoniveum and indicates its potential for use in biological control of insects. PMID:25606002

  10. 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.

  11. An active viscoelastic metamaterial for isolation applications

    International Nuclear Information System (INIS)

    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. (paper)

  12. 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

  13. 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

  14. Unfolded Protein Response Pathways in Bloodstream-Form Trypanosoma brucei?

    OpenAIRE

    Tiengwe, Calvin; Brown, Abigail E. N. A.; Bangs, James D.

    2015-01-01

    The unfolded protein response (UPR) is a stress mechanism to cope with misfolded proteins in the early secretory pathway, the hallmark being transcriptional upregulation of endoplasmic reticulum (ER) molecular chaperones such as BiP and protein disulfide isomerase. Despite the lack of transcriptional regulation and the absence of the classical UPR machinery, African trypanosomes apparently respond to persistent ER stress by a UPR-like response, including upregulation of BiP, and a related spl...

  15. Probing for primary functions of prohibitin in Trypanosoma brucei

    Czech Academy of Sciences Publication Activity Database

    Týč, Jiří; Faktorová, Drahomíra; Kriegová, Eva; Jirků, Milan; Vávrová, Zuzana; Maslov, D. A.; Lukeš, Julius

    2010-01-01

    Roč. 40, č. 1 (2010), s. 73-83. ISSN 0020-7519 R&D Projects: GA ČR GA204/09/1667; GA AV ČR IAA500960705; GA ČR(CZ) GP204/06/P423 Institutional research plan: CEZ:AV0Z60220518 Keywords : prohibitin * mitochondrion * morphology * mitochondrial translation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.822, year: 2010

  16. 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...

  17. Modes of flagellar assembly in Chlamydomonas reinhardtii and Trypanosoma brucei

    OpenAIRE

    Höög, Johanna L.; Lacomble, Sylvain; O’Toole, Eileen T.; Hoenger, Andreas; McIntosh, J. Richard; Gull, Keith

    2014-01-01

    eLife digest Some cells have a whip-like appendage called a flagellum. This is most often used to propel the cell, notably in sperm cells, but it can also be involved in sensing cues in the surrounding environment. Flagella are found in all three domains of life—the eukaryotes (which include the animals), bacteria and ancient, single-celled organisms called Archaea—and they perform similar functions in each domain. However, they also differ significantly in their protein composition, overall ...

  18. A comprehensive analysis of Trypanosoma brucei mitochondrial proteome

    Czech Academy of Sciences Publication Activity Database

    Panigrahi, A. K.; Ogata, Y.; Zíková, Alena; Anupama, A.; Dalley, R. A.; Acestor, N.; Myler, P. J.; Stuart, K. D.

    2009-01-01

    Roč. 9, č. 2 (2009), s. 434-450. ISSN 1615-9853 Keywords : database * mass spectrometry * mitochondrion * organelle fractionation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.426, year: 2009

  19. Seismic assessment of bridge structures isolated by a shape memory alloy/rubber-based isolation system

    International Nuclear Information System (INIS)

    This paper explores the effectiveness of shape memory alloy (SMA)/rubber-based isolation systems for seismic protection of bridges against near-field earthquakes by performing a sensitivity analysis. The isolation system considered in this study consists of a laminated rubber bearing, which provides lateral flexibility while supplying high vertical load-carrying capacity, and an auxiliary device made of multiple loops of SMA wires. The SMA device offers additional energy dissipating and re-centering capability. A three-span continuous bridge is modeled with the SMA/rubber-based (SRB) isolation system. Numerical simulations of the bridge are conducted for various near-field ground motions that are spectrally matched to a target design spectrum. The normalized forward transformation strength, forward transformation displacement and pre-strain level of the SMA device, ambient temperature and the lateral stiffness of the rubber bearings are selected as parameters of the sensitivity study. The variation of the seismic response of the bridge with the considered parameters is assessed. Also, the performance of the SRB isolation system with optimal design parameters is compared with an SMA-based sliding isolation system. The results indicate that the SRB isolation system can successfully reduce the seismic response of highway bridges; however, a smart isolation system that combines sliding bearings together with an SMA device is more efficient than the SRB isolation system

  20. 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...

  1. 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.

  2. 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.

  3. Isolation of lactic acid bacteria from Malaysian foods and assessment of the isolates for industrial potential.

    Science.gov (United States)

    Mohd Adnan, Ahmad Faris; Tan, Irene K P

    2007-05-01

    Two traditional fermented food 'tapai' (fermented tapioca) and 'tempoyak' (fermented durian flesh), chilli puree and fresh goat's milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from 'tapai', produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat's milk. PMID:16872826

  4. 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.

  5. 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.

  6. 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.

  7. K-Basins isolation barriers summary report

    International Nuclear Information System (INIS)

    The purpose of this report is to provide an information summary for the 100-K Area fuel storage basins design change. The design change was made to resolve an unreviewed safety question related to potential water leakage from the basin following a design basis earthquake. The design change consists of installing isolation barriers in the K-East and K-West Basins. The barriers are installed in each basin to isolate the fuel storage portion of the basin from the location of the potential seismic induced leak. The summary represented by this report provides information on the issue, the courses of corrective action, the technical work to support the corrective action, and the fabrication, installation, testing of the isolation barriers

  8. Isolated systems with wind power. Main report

    DEFF Research Database (Denmark)

    Lundsager, P.; Bindner, Henrik W.; Clausen, Niels-Erik; Frandsen, S.; Hansen, L.H.; Hansen, Jens Carsten

    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...... for Isolated Systems with Wind Power, applicable for international organisations such as donoragencies and development banks.......-user demands, analysis of findings and development of proposed guidelines. The project is reported in one main report and four topical reports, all of themissued as Risø reports. This is the Main Report Risø-R-1256, summing up the activities and findings of the project and outlining an Implementation Strategy...

  9. 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.

  10. 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.

  11. 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

  12. Escape mechanisms of African trypanosomes: why trypanosomosis is keeping us awake.

    Science.gov (United States)

    Cnops, Jennifer; Magez, Stefan; De Trez, Carl

    2015-03-01

    African trypanosomes have been around for more than 100 million years, and have adapted to survival in a very wide host range. While various indigenous African mammalian host species display a tolerant phenotype towards this parasitic infection, and hence serve as perpetual reservoirs, many commercially important livestock species are highly disease susceptible. When considering humans, they too display a highly sensitive disease progression phenotype for infections with Trypanosoma brucei rhodesiense or Trypanosoma brucei gambiense, while being intrinsically resistant to infections with other trypanosome species. As extracellular trypanosomes proliferate and live freely in the bloodstream and lymphatics, they are constantly exposed to the immune system. Due to co-evolution, this environment however no longer poses a hostile threat, but has become the niche environment where trypanosomes thrive and obligatory await transmission through the bites of tsetse flies or other haematophagic vectors, ideally without causing severe side infection-associated pathology to their host. Hence, African trypanosomes have acquired various mechanisms to manipulate and control the host immune response, evading effective elimination. Despite the extensive research into trypanosomosis over the past 40 years, many aspects of the anti-parasite immune response remain to be solved and no vaccine is currently available. Here we review the recent work on the different escape mechanisms employed by African Trypanosomes to ensure infection chronicity and transmission potential. PMID:25479093

  13. 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...

  14. Broadband Faraday isolator for gravitational wave detectors

    CERN Document Server

    Parfenov, V A

    2002-01-01

    In this paper, we report on the concept and performance of a highly effective broadband Faraday isolator. This device is based on Nd:Fe:B permanent magnets and can be used in interferometric gravitational wave detectors in which lasers oscillating in the visible or near infrared region are used. The degree of optical isolation of 30 dB, provided by the device, is achieved when operating with laser beams of up to 2 mm, and up to 25 dB when the aperture of the magneto-optic element (10 mm) is completely filled.

  15. Entropy decrease in an isolated mesoscopic system

    CERN Document Server

    Crosignani, B; Conti, C

    2003-01-01

    The analysis of the dynamical behavior of a system consisting of two isolated cavities, filled with a gas and separated by a moving adiabatic wall, reveals that the entropy of such an isolated system can undergo a significant decrease. This notable result is extremely sensitive to the system dimensions, any appreciable deviation from a mesoscopic scale of the order of one micron rendering our conclusions invalid, so that no implications can be drawn from our results on the validity of the second law of thermodynamics at a macroscopic level.

  16. 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)

  17. Glassy dynamics in condensed isolated polymer chains.

    Science.gov (United States)

    Tress, Martin; Mapesa, Emmanuel U; Kossack, Wilhelm; Kipnusu, Wycliffe K; Reiche, Manfred; Kremer, Friedrich

    2013-09-20

    In the course of miniaturization down to the nanometer scale, much remains unknown concerning how and to what extent the properties of materials are changed. To learn more about the dynamics of condensed isolated polymer chains, we used broadband dielectric spectroscopy and a capacitor with nanostructured electrodes separated by 35 nanometers. We measured the dynamic glass transition of poly(2-vinylpyridine) and found it to be bulk-like; only segments closer than 0.5 nanometer to the substrate were weakly slowed. Our approach paves the way for numerous experiments on the dynamics of isolated molecules. PMID:24052303

  18. 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.

  19. Harvesting vibrations via 3D phononic isolators

    Science.gov (United States)

    Psarobas, Ioannis E.; Yannopapas, Vassilios; Matikas, Theodore E.

    2016-05-01

    We report on the existence of unidirectional phononic band gaps that may span over extended regions of the Brillouin zone and can find application in trapping elastic (acoustic) waves in properly designed multilayered 3D structures. Phononic isolators operate as a result of asymmetrical wave transmission through a slab of a crystallographic phononic structure with broken mirror symmetry. Due to the use of lossless materials in the crystal, the absorption rate is dramatically enhanced when the proposed isolator is placed next to a vibrational harvesting cell. xml:lang="fr"

  20. The elastic modulus of isolated polytetrafluoroethylene filaments

    Directory of Open Access Journals (Sweden)

    Patrick Drawe

    2014-09-01

    Full Text Available We report vibrational Raman spectra of small extended perfluoro-n-alkanes (CnF2n+2 with n = 6, 8–10, 12–14 isolated in supersonic jet expansions and use wavenumbers of longitudinal acoustic vibrations to extrapolate the elastic modulus of cold, isolated polytetrafluoroethylene filaments. The derived value E = 209(10 GPa defines an upper limit for the elastic modulus of the perfectly crystalline, noninteracting polymer at low temperatures and serves as a benchmark for quantum chemical predictions.

  1. 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...

  2. 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.

  3. 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...

  4. Isolated non-chylous pleural effusion in two neonates.

    OpenAIRE

    Hwang, Ji Young; Yoo, Jeong Hyun; Suh, Jeong Soo; Rhee, Chung Sik

    2003-01-01

    Isolated pleural effusion, so called primary pleural effusion denotes a pleural effusion without documented etiology such as a cardiac, inflammatory, iatrogenic problem or fetal hydrops. Chromosomal anomaly such as Down syndrome may be associated with isolated pleural effusion. The content of the isolated pleural effusion is mostly chylous, and isolated non-chylous pleural effusion in neonate is rare. We experienced 2 cases of isolated non-chylous pleural effusion. They had neither cardiac pr...

  5. 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.

  6. 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.

  7. Isolation of mycoplasmas from a buzzard, falcons and vultures.

    Science.gov (United States)

    Poveda, J B; Giebel, J; Kirchhoff, H; Fernandez, A

    1990-10-01

    Thirteen mycoplasmas were isolated from a peregrine falcon (Falco peregrinus), two saker falcons (Falco cherrug), a buzzard (Buteo buteo), a black vulture (Aegypius monachus), and two griffon vultures (Gypsfuhus). Six of them could be identified: Mycoplasma gallinarum (three isolates), M. columborale (two isolates) and M. anatis (one isolate). The remaining seven isolates did not react with antisera against the known avian mycoplasma species in the indirect immunofluorescence and growth inhibition tests. They may represent new species. PMID:18679987

  8. Ceftaroline versus isolates from animal bite wounds: comparative in vitro activities against 243 isolates, including 156 Pasteurella species isolates.

    Science.gov (United States)

    Goldstein, Ellie J C; Citron, Diane M; Merriam, C Vreni; Tyrrell, Kerin L

    2012-12-01

    More than 5 million Americans are bitten by animals, usually dogs, annually. Bite patients comprise ∼1% of all patients who visit emergency departments (300,000/year), and approximately 10,000 require hospitalization and intravenous antibiotics. Ceftaroline is the bioactive component of the prodrug ceftaroline fosamil, which is FDA approved for the treatment of acute bacterial skin and skin structure infections (ABSSSIs), including those containing methicillin-resistant Staphylococcus aureus (MRSA). There are no in vitro data about the activity of ceftaroline against Pasteurella multocida subsp. multocida and Pasteurella multocida subsp. septica, other Pasteurella spp., or other bite wound isolates. We therefore studied the in vitro activity of ceftaroline against 243 animal bite isolates. MICs were determined using the broth microdilution method according to CLSI guidelines. Comparator drugs included cefazolin, ceftriaxone, ertapenem, ampicillin-sulbactam, azithromycin, doxycycline, and sulfamethoxazole-trimethoprim (SMX-TMP). Ceftaroline was the most active agent against all 5 Pasteurella species, including P. multocida subsp. multocida and P. multocida subsp. septica, with a maximum MIC of ≤0.008 μg/ml; more active than ceftriaxone and ertapenem (MIC(90)s, ≤0.015 μg/ml); and more active than cefazolin (MIC(90), 0.5 μg/ml) doxycycline (MIC(90), 0.125 μg/ml), azithromycin (MIC(90), 0.5 μg/ml), ampicillin-sulbactam (MIC(90), 0.125 μg/ml), and SMX-TMP (MIC(90), 0.125 μg/ml). Ceftaroline was also very active against all S. aureus isolates (MIC(90), 0.125 μg/ml) and other Staphylococcus and Streptococcus species, with a maximum MIC of 0.125 μg/ml against all bite isolates tested. Ceftaroline has potential clinical utility against infections involving P. multocida, other Pasteurella species, and aerobic Gram-positive isolates, including S. aureus. PMID:23027193

  9. 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

  10. 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...

  11. 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.

  12. RHEOLOGY OF EXTRUDED WHEY PROTEIN ISOLATE

    Science.gov (United States)

    Whey protein isolate (WPI), a high-quality protein used to fortify a number of foods, may be texturized with a twin-screw extruder. Since extrusion of food is commonly performed above 70°C, which causes whey protein to denature, cold extrusion below 70°C was investigated to determine the effects on...

  13. 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…

  14. 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

  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. 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

  17. 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.

  18. Isolation of Mitochondria from Potato Tubers

    DEFF Research Database (Denmark)

    Havelund, Jesper F.; Salvato, Fernanda; Chen, Mingjie;

    2014-01-01

    vivo properties of the organelle inside the plant cell. Here, we describe a method to isolate mitochondria from a relatively homogeneous plant tissue, the dormant potato tuber. The homogenization is done using a juice extractor, which is a relatively gentle homogenization procedure where the...

  19. Isolated Fournier's gangrene of the penis.

    Science.gov (United States)

    Obi, A O

    2016-01-01

    To share experience on the presentation and management of 4 cases of isolated penile Fournier's gangrene. Clinical and demographic data of four patients with isolated penile Fournier's gangrene seen over an 8-year period (January 2006-December 2013) were reviewed. All patients had intravenous fluid resuscitation, emergency surgical debridement, and broad-spectrum intravenous antibiotics. Fournier's gangrene of the penis was, respectively, due to long segment anterior urethral stricture, penile edema from poorly controlled congestive cardiac failure, penile abrasion from oral sex and idiopathic. The mean age of the patients was 34.3 ± 5.6 years. One patient with urethral stricture had urinary tract infection. The patients presented with a prodromal period of genital pain and fever followed by genital swelling, gangrene, and ulceration. The most common wound swab isolates were Staphylococcus aureus and Escherichia coli. Only the skin and dartos fascia were affected with sparing of the corporal cylinders. Mean hospital stay was 17.3 ± 3.0 days and mean Fournier's gangrene severity index (FGSI) was 4.0 ± 0.8. Wound closure was achieved by split skin grafting in 2 patients, delayed primary closure in the third and healing by secondary intention in the fourth patient. Subjectively assessed erectile function was preserved in all four patients. Isolated Fournier's gangrene of the penis is very rare. It is associated with low FGSI and sparing of the three corporal cylinders. It may rarely follow oral sexual practice. PMID:27022814

  20. 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.

  1. Isolation of Circulating Tumor Cells by Dielectrophoresis

    International Nuclear Information System (INIS)

    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

  2. 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...

  3. 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.

  4. Isolation of actinomycetes from cervical specimens.

    OpenAIRE

    Traynor, R M; Parratt, D; Duguid, H L; Duncan, I D

    1981-01-01

    Cervical smears from 30 women were examined. Fifteen of these had actinomycetes visible by direct smear examination and the organisms were isolated in 13. Of the remainder, all had negative smears and culture was similarly negative in 12, whilst in 3, the cultures were either positive (1) or suspicious (2).

  5. 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…

  6. 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…

  7. Aminoglycoside resistance among isolates of nosocomial Enterobacteriaceae

    International Nuclear Information System (INIS)

    Fifty-seven gentamicin-resistant isolates of Enterobacteriaceae, obtained from patients attending hospital, were examined for the production of aminoglycoside-modifying enzymes. Of the 51 strains producing such enzymes, 34 were presumptively plasmid-mediated as indicated by conjugation experiments

  8. 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.

  9. 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

  10. ISOLATION OF CHICKEN FOLLICULAR DENDRITIC CELLS

    Science.gov (United States)

    The aim of the present study was to isolate chicken follicular dendritic cells (FDC). A combination of methods involving panning, iodixanol density gradient centrifugation, and magnetic cell separation technology made it possible to obtain functional FDC from the cecal tonsils from chickens, which h...

  11. 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...

  12. 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)

  13. 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...

  14. 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.

  15. 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.

  16. Isolated cleft sternum: Neonatal surgical treatment

    Directory of Open Access Journals (Sweden)

    Kanojia Ravi

    2007-01-01

    Full Text Available Isolated cleft sternum is a rare congenital defect of the anterior chest wall and is the result of failed ventral midline fusion of sternal bands. We present two cases operated 18 and 24 days after birth with satisfactory results. Surgery is indicated to protect the heart and mediastinal contents.

  17. Isolated prompt photon production at CDF

    International Nuclear Information System (INIS)

    This note describes measurements of isolated prompt photon production at √s = 1.8 TeV using the CDF experiment. The measurements are compared to recent NLO QCD calculations, including recently obtained parton distribution functions. Qualitatively, the QCD calculation with the new parton distribution functions agrees better with the data than the previous parton distribution functions

  18. Isolated prompt photon production at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Maas, P.A. [Wisconsin Univ., Madison, WI (United States); CDF Collaboration

    1992-11-01

    This note describes measurements of isolated prompt photon production at {radical}s = 1.8 TeV using the CDF experiment. The measurements are compared to recent NLO QCD calculations, including recently obtained parton distribution functions. Qualitatively, the QCD calculation with the new parton distribution functions agrees better with the data than the previous parton distribution functions.

  19. 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

  20. 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...