10 research outputs found
Aerial elephant count in the Shimba Hills ecosystem, Kenya
Get PDFConducted by helicopter in the Shimba Hills ecosystem in August 1997 a one day wet season count observed 464 elephant, and served to verify the estimated 412 obtained through dung counts. 150 of the animals were in Mwaluganje Forest, giving a density of 6 elephant per sq km in this area. The population in the Forest has probably been increasing since the 1950's. Shimba Hills National Reserve itself is enclosed by an electric fence. A wildlife corridor, namely the Mwaluganje Community Conservation Area, joins the Reserve and the Forest but there is no additional habitat/range for this isolated population which is literally surrounded by human habitation and agricultural land. Vegetation damage by elephants in the Shimba Hills ecosystem has reached critical levels in localized areas, and the area's biodiversity may suffer if management action is not taken soon. The author discusses the growth of the population and the differing opinions of researchers who have undertaken previous surveys. He conclusions are in line with a recent consultant's report (Kamanga, 1997) who suggested 200 animals should be removed, and that a density of 0.5 elephants per sq km is probably good for the Shimba ecosystem. Translocation is suggested as an option to consider followed up by a population control immunocontraception programme
Tsetse bloodmeal analyses incriminate the common warthog Phacochoerus africanus as an important cryptic host of animal trypanosomes in smallholder cattle farming communities in Shimba Hills, Kenya
Get PDFTable S1: Data on tsetse fly bloodmeal hosts and trypanosome
infections in the different study-blocks in Shimba Hills, Kenya.Data Availability Statement: The dataset used and/or analysed during the current study are available from the corresponding author FIE on reasonable request. DNA sequences of vertebrate
species generated during the current study are available in the GenBank under accession numbers:
MZ816958-MZ816971.Trypanosomes are endemic and retard cattle health in Shimba Hills, Kenya. Wildlife in the area act as reservoirs of the parasites. However, wild animal species that harbor and expose cattle to tsetse-borne trypanosomes are not well known in Shimba Hills. Using xeno-monitoring surveillance to investigate wild animal reservoirs and sources of trypanosomes in Shimba Hills, we screened 696 trypanosome-infected and uninfected tsetse flies for vertebrate DNA using multiplegene PCR-High Resolution Melting analysis and amplicon sequencing. Results revealed that tsetse flies fed on 13 mammalian species, preferentially Phacochoerus africanus (warthogs) (17.39%, 95% CI: 14.56–20.21) and Bos taurus (cattle) (11.35%, 95% CI: 8.99–13.71). Some tsetse flies showed positive cases of bloodmeals from multiple hosts (3.45%, 95% CI: 2.09–4.81), including warthog and cattle (0.57%, 95% CI: 0.01–1.14). Importantly, tsetse flies that took bloodmeals from warthog had significant risk of infections with Trypanosoma vivax (5.79%, 95% CI: 1.57–10.00), T. congolense (7.44%, 95% CI: 2.70–12.18), and T. brucei sl (2.48%, 95% CI: 0.33–5.29). These findings implicate warthogs as important reservoirs of tsetse-borne trypanosomes affecting cattle in Shimba Hills and provide valuable epidemiological insights to underpin the parasites targeted management in Nagana vector control programs in the area.A German Academic Exchange Service (DAAD) in-region postgraduate scholarship; the BioVision Foundation Switzerland; European Union’s Integrated Biological Control Applied Research Programme—tsetse repellent component; the German Ministry for Economic Cooperation and Development (BMZ) through the Deutsche Gesellschaft für Internationale Zusammenarbeit; UK’s Department for International Development (DFID); Swedish International Development Cooperation Agency (SIDA); the Swiss Agency for Development and Cooperation (SDC); and the Kenyan Government.https://www.mdpi.com/journal/pathogensam2022Zoology and Entomolog
191 A photonic band calculation with the SS method combined with the BEM and its acceleration technique.
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A framework of shape optimisation based on the isogeometric boundary element method toward designing thin-silicon photovoltaic devices
No full text187 A development of isogeometric BEM for 1-periodic boundary value problems for wave problems
No full textRoberto Tibau and the process of making architecture
No full textEste estudo documenta a vida e a obra de Roberto José Goulart Tibau (1924-2003), arquiteto brasileiro. O objetivo fundamental - e mais importante - é reunir informações sobre os projetos e obras mais significativos desenvolvidos durante sua atividade profissional, tornando-os acessíveis através dessa pesquisa. O trabalho baseou-se em pesquisa bibliográfica, levantamento e registro das obras e projetos realizados, currículo profissional, e depoimento de Tibau, concedido ao autor, em 1998. Em Roberto Tibau e o fazer arquitetura são descritos os caminhos percorridos pelo arquiteto; o contexto histórico de sua formação e atuação profissional; a relação de sua produção arquitetônica com outras obras da época; e eventuais referências projetuais utilizadas na criação dos seus projetos. Este trabalho vem preencher uma lacuna bibliográfica considerável, trazendo à luz, a obra deste significativo arquiteto, que dedicou sua vida ao trabalho na prancheta, na qual deixou sua marca de humanista.This study documents the life and work of Roberto José Goulart Tibau (1924-2003), a Brazilian architect. It aims to collect information about the most significant projects developed during the years of his professional career, which will become available through this research. The present study based on bibliographical research, examination and registration of the projects executed by the architect, his resumé, and his testimonial to the author of this research, in 1998. In Roberto Tibau and the process of making architecture there is a description of the ways in which his projects were conceived; the historical context through his professional activity since graduation, the relation between his own production and the production of other architects of the same period, and the projecting references used for his creations. This research is also an attempt to fill a signicant bibliographical gap of architecture history in Brazil by bringing to light the work of this relevant architect, who dedicated his life to working on his drawing table, leaving to us his humanistic style
Screening for improved activity of a transglutaminase from Streptomyces mobaraensis created by a novel rational mutagenesis and random mutagenesis
Get PDFMicrobial transglutaminase (MTG) has been used extensively in academic research and the food industries through its cross-linking or posttranslational modification of proteins. To improve MTGT, a novel method of rational mutagenesis, called WASH-ROM (Water Accessible Surface Hot-space Region Oriented Mutagenesis), was first attempted. Based on the three-dimensional structure of MTG, 151 point mutations were selected at 40 different residues bearing high solvent accessibility surface area, within a 15 Å of the active center site nucleophile, Cys64. Among them, 32 mutants showed higher specific activity than the wild type enzyme. We found that beneficial mutations are distributed in two regions and with distinctive amino acid substitutions. Next, random mutagenesis was applied to the entire MTG region by developing a new plate assay-based screening system, using Corynebacterium glutamicum as the secretion host strain. This in vivo screening system allowed us to readily distinguish the change in enzymatic activity upon mutation by monitoring the intensity of enzymatic reaction-derived color zones which appeared around the recombinant cell colonies on the plate. From the library of 24,000 clones, 10 mutants were finally selected as beneficial enzymes exhibiting higher specific activity than wild type. Notably, most of the mutations differed from those obtained by WASH-ROM, except for H289Y. Beneficial mutations were distributed in two other regions as well. Furthermore, we found that the FRAP-S199A mutant (FRAP: N-terminal four amino acid residues extension) showed the highest specific activity (45 U/mg: 1.7 times higher than the wild type enzyme). Through these different mutation approaches, various beneficial positions leading to increased specific activity of MTG were surveyed
A development of the isogeometric boundary element method based on Burton-Miller boundary integral equation for wave problems
No full textMolecular and developmental analysis of non-coding RNA metabolism in" C. elegans" : the exoribonuclease XRN2 and the RNA- binding proteins SART-3 and USIP-1
Get PDFAbout three quarters of a eukaryotic genome are transcribed into RNA. However, only <2% of these transcripts are translated into protein while the bulk of transcripts execute their biological function as RNA. Non-protein coding RNAs (ncRNAs) associate with proteins in ribonucleoprotein particles (RNPs) to regulate gene expression at various stages thereby greatly increasing the functional complexity of the genome. Nonetheless, the function and mode of action of the vast majority of ncRNAs is unknown and even in well studied examples little is known about the post-transcriptional regulation of ncRNAs themselves. In the thesis at hand, I explored the molecular and developmental functions of proteins implicated in the metabolism of ncRNAs, namely the miRNA-degrading enzyme XRN2 and the U6 snRNA-interacting proteins SART-3 and USIP-1. The XRN2 project was a collaboration with Takashi Miki and Hannes Richter.
XRN2 project
XRN2 is a conserved 5’-to-3’ exoribonuclease involved in various pathways including transcription termination and processing of precursor forms of rRNAs and snoRNAs. Our lab had established a function of XRN2 in the turnover of mature miRNAs, however, whether XRN2 targets all or specific miRNAs in vivo remained unclear. Although XRN2 substrates have extensively been characterized, the developmental function of XRN2 is essentially unexplored. Moreover, knowledge of co-factors regulating XRN2 function beyond transcription termination is scarce in multicellular organisms. In order to elucidate the developmental role of XRN2, we characterized an xrn-2 null and xrn-2 temperature-sensitive mutant. We found that XRN2 is essential during several stages of C. elegans development, including embryogenesis, and that only specific miRNAs are affected by XRN2 in vivo. Co-immunoprecipitations identified PAXT-1 (PArtner of XRN-Two 1) as a tight interaction partner of XRN2. paxt-1 depletion enhanced the xrn-2ts mutant phenotype and a paxt-1 null mutant slowed-down miRNA degradation in vivo, similar to XRN2 inactivation. These observations, as we showed, are due to a stabilizing effect of PAXT-1 on XRN2. Truncation mutants of PAXT-1 revealed a conserved N-terminal domain of unknown function, DUF3469, sufficient for XRN2 binding. We were excited to discover that human proteins containing DUF3469 were also able to bind to XRN2. Hence, we renamed DUF3469 to XRN2-binding domain (XTBD). Collectively, we identified PAXT-1 as an essential interaction partner of XRN2 in C. elegans and established a protein domain (XTBD) that serves as a binding platform for XRN2 beyond C. elegans.
Finally, the laboratory of Dr. Martin Simard found that the scavenger decapping enzyme DCS-1 interacts with the exonuclease XRN1, a paralogue of XRN2, to promote miRNA degradation in C. elegans. Collaborating on their project, I evaluated the subcellular localization of XRN1 and XRN2 in C. elegans and provided tools useful to their experiments such as an XRN1 antibody. This collaborative work has been published and can be found in section 7.
SART-3 project
The human protein SART3 and its yeast homolog Prp24 have previously been implicated in spliceosome assembly, namely the association of the U4 and U6 snRNP into the U4/U6 di-snRNP complex. Additionally, a physical interaction of SART3 with the Argonaute proteins AGO1 and AGO2 had been reported, suggesting an involvement of SART3 in the miRNA pathway. However, a putative function of SART3 in the miRNA pathway remained to be established. In order uncover such a function and to shed light on the so far largely neglected systemic role of SART3 in a multicellular context, I investigated its C. elegans homolog SART-3. Co-immunoprecipitations of SART-3 revealed an interaction with a previously uncharacterized putative terminal uridylyl transferase (TUTase), whereas I could not verify an interaction between SART-3 and AGO1/AGO2. It is known that SART3 binds specifically to the U6 snRNA which contains a post-transcriptionally elongated uridine (U)-tail essential for spliceosome assembly. Therefore it was appealing to assume that this U-tail is polymerized by the identified TUTase. Subsequent analyses unveiled an interaction between the TUTase and U6 snRNA, which hence was renamed to U Six snRNA Interacting Protein 1 (USIP-1). It appeared that USIP-1 binds to a U6 snRNA species that is devoid of Lsm proteins suggesting a role for USIP-1 early in spliceosome assembly. Moreover, knock-down of sart-3 in a usip-1 null mutant background led to a synthetic, embryonic lethal phenotype. This phenotype was rescued by transgenic expression of wild-type USIP-1. Although formal demonstration of TUTase-activity for USIP-1 is lacking, the synthetic lethality was not rescued by a supposedly catalytically inactive version of USIP-1. In sum, I established a physical and functional interaction between two previously uncharacterized proteins in C. elegans, SART-3 and USIP-1, and explored their developmental phenotypes
