Biology of tRNA halves in Trypanosoma brucei

Although T. brucei has to challenge tremendous environment changes, e.g. switch from the bloodstream form in mammalian hosts to the mid gut form present in tsetse flies, there is no evidence for differential regulation of RNA Pol II transcription. Instead, constitutive transcription appears to occur. This observation indicates that protein levels have to be regulated by post-transcriptional mechanisms. It has been shown that non-protein coding RNAs (ncRNAs) are crucial in regulatory networks (e.g. chromosome remodelling; RNA polymerase activity; mRNA turnover; etc.), but all of the recently discovered ncRNAs involved in translation regulation target the mRNA rather than the ribosome. This is unexpected, since the ribosome has a central role during gene expression and due to the assumption that the primordial translation system most likely received direct regulatory input from small molecules including ncRNA cofactors. In our lab, it has been discovered that ncRNAs are able to directly bind to the ribosome, therefore influencing the translation rate in Haloferax volcanii and Saccharomyces cerevisiae. In order to extend this idea of ribosome-binding ncRNAs in mammalian parasites, we want to investigate this mechanism in T. brucei. Accordingly, we performed a genomic screen for small ribosome-associated RNAs followed by functional analyses of possible candidates. With the help of this genomic screen, we found tRNAs that are alternated and tRNA halves that are differentially expressed upon nutritional stress.

Biology of tRNA halves in Trypanosoma brucei

Although T. brucei has to challenge tremendous environment changes, e.g. switch from the bloodstream form in mammalian hosts to the mid gut form present in tsetse flies, there is no evidence for differential regulation of RNA Pol II transcription. Instead, constitutive transcription appears to occur. This observation indicates that protein levels have to be regulated by post-transcriptional mechanisms. It has been shown that non-protein coding RNAs (ncRNAs) are crucial in regulatory networks (e.g. chromosome remodelling; RNA polymerase activity; mRNA turnover; etc.), but all of the recently discovered ncRNAs involved in translation regulation target the mRNA rather than the ribosome. This is unexpected, since the ribosome has a central role during gene expression and due to the assumption that the primordial translation system most likely received direct regulatory input from small molecules including ncRNA cofactors. In our lab, it has been discovered that ncRNAs are able to directly bind to the ribosome, therefore influencing the translation rate in Haloferax volcanii and Saccharomyces cerevisiae. In order to extend this idea of ribosome-binding ncRNAs in mammalian parasites, we want to investigate this mechanism in T. brucei. Accordingly, we performed a genomic screen for small ribosome-associated RNAs followed by functional analyses of possible candidates. With the help of this genomic screen, we found tRNAs that are alternated and tRNA halves that are differentially expressed upon nutritional stress.

Selection of the N-Acylhomoserine Lactone-Degrading Bacterium Alteromonas stellipolaris PQQ-42 and of Its Potential for Biocontrol in Aquaculture

The production of virulence factors by many pathogenic microorganisms depends on the intercellular communication system called quorum sensing, which involves the production and release of signal molecules known as autoinducers. Based on this, new-therapeutic strategies have emerged for the treatment of a variety of infections, such as the enzymatic degradation of signaling molecules, known as quorum quenching (QQ). In this study, we present the screening of QQ activity amongst 450 strains isolated from a bivalve hatchery in Granada (Spain), and the selection of the strain PQQ-42, which degrades a wide range of N-acylhomoserine lactones (AHLs). The selected strain, identified as Alteromonas stellipolaris, degraded the accumulation of AHLs and reduced the production of protease and chitinase and swimming motility of a Vibrio species in co-cultivation experiments in vitro. In the bio-control experiment, strain PQQ-42 significantly reduced the pathogenicity of Vibrio mediterranei VibC-Oc-097 upon the coral Oculina patagonica showing a lower degree of tissue damage (29.25 ± 14.63%) in its presence, compared to when the coral was infected with V. mediterranei VibC-Oc-097 alone (77.53 ± 13.22%). Our results suggest that this AHL-degrading bacterium may have biotechnological applications in aquaculture.

Coasts, Mediterranean Sea Region, East, 1680-1689 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Orientalior districtus Maris Mediterranei = T' Ooster gedeelte van de Middelandse Zee. It was published by Fred. de Wit, between 1680 and 1689. Scale [ca. 1:4,500,000]. Covers Mediterranean Sea, Black Sea, and coasts of Europe, North Africa, and the Middle East. Map in Latin and Dutch.The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Includes index.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Coasts, Mediterranean Sea Region, West, 1680-1689 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Occidentalior Tractus Maris Mediterranei = Wester gedeelte van de Middelandse Zee. It was published by Fred. de Wit, between 1680 and 1689. Scale [ca. 1:4,500,000]. Scale [ca. 1:4,500,000]. Covers Mediterranean Sea and coasts of Europe and North Africa. Map in Latin and Dutch. The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Includes index.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Mediterranean Sea Region, West, 1690-1699 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Accuratissima occidentalioris districtus maris Mediterranei tabula, authore Iusto Danckerts. It was published by Iusto Danckerts, between 1690 and 1699. Scale [ca. 1:5,300,000]. Covers the western Mediterranean Sea region. Map in Latin. The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, shoreline features, and more. Relief shown pictorially.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Mediterranean Sea Region, East, 1690-1699 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Accuratissima orientalioris districtus maris Mediterranei tabula, authore Iusto Danckerts. It was published by Iusto Danckerts, between 1690 and 1699. Scale [ca. 1:5,300,000]. Covers the eastern Mediterranean Sea region. Map in Latin. The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, shoreline features, and more. Relief shown pictorially.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Traduzione audiovisiva e format gastronomici: proposta di sottotitolaggio in italiano e in francese della finale di Masterchef

In questo mio elaborato ho affrontato il tema della traduzione audiovisiva. Mi sono soffermata sulla tecnica del sottotitolaggio, concentrando la mia attenzione sui format televisivi di cucina. Sono stata spinta da una vera e propria passione per tutto ciò che riguarda la sfera gastronomica e i programmi televisivi a questa dedicati. Oggi queste trasmissioni hanno raggiunto un vero e proprio successo mondiale. La nostra è l’era dei grandi format televisivi che non parlano altro che di cucina, sfide tra i fornelli e critiche spietate. La cucina è alla base di ogni civiltà ed è parte integrante della cultura di ogni popolo. Tra le molteplici sfaccettature delle culture, troviamo la gastronomia che, dal mio punta di vista, è situata ai primi posti per importanza. L’Italia e la Francia hanno, sin da sempre, dimostrato la loro eccellenza all’interno del panorama mondiale enogastronomico: la cucina italiana, con la sua semplicità e i suoi sapori mediterranei, e quella francese, ricca di note tradizionali ed esotiche all’unisono. Per questo motivo, la mia attenzione si è rivolta a un talk show culinario ormai noto in tutto il mondo: MasterChef. In questo format televisivo, i concorrenti sono tenuti a sostenere varie prove, nelle quali bisogna realizzare piatti dell’arte culinaria del paese in cui il programma viene trasmesso e non solo. Scopo del programma è aggiudicarsi il titolo di miglior chef. Ho scelto chiaramente un’edizione a mio piacimento del programma per entrambi i paesi e ho proposto un sottotitolaggio per un particolare momento di questo format televisivo: la finale. Nella fattispecie, ho proposto il sottotitolaggio per la finale di MasterChef Italia in francese e per la finale di MasterChef France in italiano. Ho scelto di sottotitolare questo particolare momento della trasmissione televisiva, in quanto ritengo che, oltre ad essere uno dei più emozionanti per i telespettatori, sia ricco di elementi utili per un’analisi approfondita in ambito traduttivo.

Discovery of a new source of rifamycin antibiotics in marine sponge actinobacteria by phylogenetic prediction

Phylogenetic analysis of the ketosynthase (KS) gene sequences of marine sponge-derived Salinispora strains of actinobacteria indicated that the polyketide synthase (PKS) gene sequence most closely related to that of Salinispora was the rifamycin B synthase of Amycolatopsis mediterranei. This result was not expected from taxonomic species tree phylogenetics using 16S rRNA sequences. From the PKS sequence data generated from our sponge-derived Salinispora strains, we predicted that such strains might synthesize rifamycin-like compounds. Liquid chromatography-tandem mass spectrometry (LC/MS/MS) analysis was applied to one sponge-derived Salinispora strain to test the hypothesis of rifamycin synthesis. The analysis reported here demonstrates that this Salinispora isolate does produce compounds of the rifamycin class, including rifamycin B and rifamycin SV. A rifamycin-specific KS primer set was designed, and that primer set increased the number of rifamycin-positive strains detected by PCR screening relative to the number detectable using a conserved KS-specific set. Thus, the Salinispora group of actinobacteria represents a potential new source of rifamycins outside the genus Amycolatopsis and the first recorded source of rifamycins from marine bacteria.