Molecular diversity, cultivation, and improved detection by fluorescent in situ hybridization of a dominant group of human gut bacteria related to Roseburia spp. or Eubacterium rectale

Peer reviewed

Woman wiring fluorescent light

Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].

Woman wiring fluorescent light

Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].

Woman wiring fluorescent light

Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].

Synthesis of a PbTx-2 photoaffinity and fluorescent probe and an alternative synthetic route to photoaffinity probes

A natural phenomenon characterized by dense aggregations of unicellular photosynthetic marine organisms has been termed colloquially as red tides because of the vivid discoloration of the water. The dinoflagellate Karenia brevis is the cause of the Florida red tide bloom. K. brevis produces the brevetoxins, a potent suite of neurotoxins responsible for substantial amounts of marine mammal and fish mortalities. When consumed by humans, the toxin causes Neurotoxic Shellfish Poisoning (NSP). The native function of brevetoxin within the organism has remained mysterious since its discovery. There is a need to identify factors which contribute to and regulate toxin production within K. brevis. These toxins are produced and retained within the cell implicating a significant cellular role for their presence. Localization of brevetoxin and identification of a native receptor may provide insight into its native role as well as other polyether ladder type toxins such as the ciguatoxins, maitotoxins, and yessotoxins. In higher organisms these polyether ladder molecules bind to transmembrane proteins with high affinity. We anticipated the native brevetoxin receptor would also be a transmembrane protein. Photoaffinity labeling has become increasingly popular for identifying ligand receptors. By attaching ligands to these photophors, one is able to activate the molecule after the ligand binds to its receptor to obtain a permanent linkage between the two. Subsequent purification provides the protein with the ligand directly attached. A molecule that is capable of fluorescence is a fluorophore, which upon excitation is capable of re-emitting light. Fluorescent labeling uses fluorophores by attaching them covalently to biologically active compounds. The synthesis of a brevetoxin photoaffinity probe and its application in identifying a native brevetoxin receptor will be described. The preparation of a fluorescent derivative of brevetoxin will be described and its use in localizing the toxin to an organelle within K. brevis. In addition, the general utility of a synthesized photoaffinity label with other toxins having similar functionality will be described. An alternative synthetic approach to a general photoaffinity label will also be discussed whose goal was to accelerate the preparation and improve the overall synthetic yields of a multifunctional label.

X-ray fluorescent (XRF) ratios and diatom groups of sediment core GeoB13813-4

The continental shelf adjacent to the Río de la Plata (RdlP) exhibits extremely complex hydrographic and ecological characteristics which are of great socioeconomic importance. Since the long-term environmental variations related to the atmospheric (wind fields), hydrologic (freshwater plume), and oceanographic (currents and fronts) regimes are little known, the aim of this study is to reconstruct the changes in the terrigenous input into the inner continental shelf during the late Holocene period (associated with the RdlP sediment discharge) and to unravel the climatic forcing mechanisms behind them. To achieve this, we retrieved a 10 m long sediment core from the RdlP mud depocenter at 57 m water depth (GeoB 13813-4). The radiocarbon age control indicated an extremely high sedimentation rate of 0.8 cm per year, encompassing the past 1200 years (AD 750-2000). We used element ratios (Ti / Ca, Fe / Ca, Ti / Al, Fe / K) as regional proxies for the fluvial input signal and the variations in relative abundance of salinity-indicative diatom groups (freshwater versus marine-brackish) to assess the variability in terrigenous freshwater and sediment discharges. Ti / Ca, Fe / Ca, Ti / Al, Fe / K and the freshwater diatom group showed the lowest values between AD 850 and 1300, while the highest values occurred between AD 1300 and 1850. The variations in the sedimentary record can be attributed to the Medieval Climatic Anomaly (MCA) and the Little Ice Age (LIA), both of which had a significant impact on rainfall and wind patterns over the region. During the MCA, a weakening of the South American summer monsoon system (SAMS) and the South Atlantic Convergence Zone (SACZ), could explain the lowest element ratios (indicative of a lower terrigenous input) and a marine-dominated diatom record, both indicative of a reduced RdlP freshwater plume. In contrast, during the LIA, a strengthening of SAMS and SACZ may have led to an expansion of the RdlP river plume to the far north, as indicated by higher element ratios and a marked freshwater diatom signal. Furthermore, a possible multidecadal oscillation probably associated with Atlantic Multidecadal Oscillation (AMO) since AD 1300 reflects the variability in both the SAMS and SACZ systems.

Assessment of Activity of 'Transparent and Clear' and 'Opaque and Highly Coloured' Photocatalytic Samples using a Fluorescent Photocatalytic Activity Indicator Ink, FPaii.

The photocatalytic activity of self-cleaning glass is assessed using a resazurin (Rz) photocatalyst activity indicator ink, i.e. Rz paii, via both the rate of change in the colour of the ink (blue to pink), R(Abs), and the rate of change in the fluorescence intensity, R(Fl), (λ(excitation) = 593 nm; λ(emission) = 639 nm) of the ink. In both cases the kinetics are zero order. Additional work with a range of glass samples of different photocatalytic activity reveal R(Abs) is directly related to R(Fl), thereby showing that the latter, like the former, can be used to provide a measure of the photocatalytic activity of the sample under test. The measured value of R(Fl) is found to be the same for 5 pieces of, otherwise identical, selfcleaning glass with: black, red, blue, yellow and no coloured tape stuck to their backs, which demonstrates that R(Fl) measurements can be used to measure photocatalytic activity under conditions of high colour and opacity under which R(Abs) cannot be measured. The relevance of this novel, fluorescence-based paii to the assessment of the activity of highly coloured, opaque photocatalytic samples, such as paints and tiles, is discussed briefly.

Leave a light on – Terracotta lamps from Agia Paraskevi of Arachamitai, from the Classical period until Roman times

This thesis deals with terracotta lamps found at the archaeological site of Agia Paraskevi of Arachamitai during the years 2010–2014. The research questions are: What kind of lamps were used on the site and when? For what purposes were the lamps used? Where were they manufactured? In order to address these questions, a total of fifty lamps have been chosen to form the body of research material. To answer the first research question, a typology for these lamps has been created with twenty-one types and one variant, after examining various lamp typologies and previous publications. The find contexts and distribution of the lamps are both examined to test the dates for the different lamp types gathered from other publications, and to answer the question on what purposes the lamps were used on the site. Visual observation of the clay of the lamps and information on clay materials from other sites are both examined to determine the lamps' origins. The lamps in this study date from the 5th century BC to the 2nd century AD. The find contexts allow the dating of the lamps according to the other publications, but suggestions of more site-specific dates are given to some lamps. The distribution of the lamps indicates that while most were used for everyday lighting at the sanctuary, some may have had ritual connections. Most of the lamps were manufactured locally or at a nearby Arcadian site. Few lamps can be regarded as imports.

A review of one-step fluorescent cyanoacrylate techniques

A review of recent research in the use of one-step fluorescent cyanoacrylate techniques is presented. Advantages and disadvantages of such techniques in comparison to two-step processes are discussed. Further studies and new experimental data are presented to aid this review: three one-step cyanoacrylate products (Lumicyano, PolyCyano UV and PECA Multiband) containing a fluorescent dye were tested to evaluate their effectiveness in developing latent fingermarks on polyethylene bags by means of a pseudo operational trial. The results were compared to the traditional two-step process of cyanoacrylate fuming followed by staining with ethanol-based basic yellow 40 (BY40). The study was conducted using sequential treatments of an initial fuming cycle, a second cycle and finally BY40 staining. LumicyanoTM and PolyCyano UV performed similarly before BY40 staining, with both providing good contrast and visibility under fluorescence. PECA Multiband, however, did not develop as many fingermarks and proved to be problematic for the fuming cabinet. Subsequent BY40 staining of fingermarks developed by all three one-step processes enabled the visualisation of new fingermarks.

Rapporto tecnico sulla ottimizzazione del processo di biosintesi di una Green Fluorescent Protein ricombinante estratta da A. sulcata

L’espressione di geni eterologhi in Escherichia coli rappresenta uno dei metodi più veloci, semplici ed economici per la produzione di ampie quantità di proteine target. Tuttavia, meccanismi di folding e le modifiche post traduzionali inducono a volte un non corretto ripiegamento delle proteine nella conformazione nativa, con successiva aggregazione in quelli che vengono definiti corpi di inclusione. Nel nostro caso, l’attenzione è stata focalizzata su una Green Fluorescent Protein (GFP) di 228 aa estratta da Anemonia sulcata, contenente un fluoroforo composto da tre amminoacidi Gln63, Tyr64, Gly65 all'interno di una struttura a barile. Il corretto folding della proteina era correlato strettamente alla funzionalità del fluoroforo. Il nostro obiettivo è stato quello, quindi, di ottimizzare il processo di biosintesi della GFP espressa in E. coli, ovviando alla formazione di corpi di inclusione contenenti la proteina (non funzionale), definendo e standardizzando inoltre, le condizioni che consentivano di produrre la più alta percentuale di GFP correttamente ripiegata (in condizioni non denaturanti) e quindi funzionale.

Bioremediation of piggery effluents using Scenedesmus Obliquus microalga [Resumo]

Effluents from intensive pig farms present high nutrient concentration, mainly ammonium, contributing to water eutrophication and pollution. Microalgae ability to deplete inorganic nutrients makes them an efficient effluent bioremediation tool. Scenedesmus obliquus was grown in piggery effluent (without any pretreatment) diluted with tap water at 5%v/v (187±25mg/L N-NH4+) and compared with growth in synthetic Bristol media. A 21-days trial was performed in 1L bubble-column reactors illuminated by fluorescent and LED lamps(3klux). Microalgae growth was monitored through OD540nm, dry weight and Chlorophyll content and also by flow cytometry in terms of autofluorescence read in FL3 channel (>670 nm), cell size (FSC), internal complexity (SSC) and cell membrane integrity (PI). S. obliquus cells have grown slower in pig effluent (mmax=0.13-19d-1) than in Bristol media (mmax=0.46-0.50d-1) although after 15 days the biomass productivity observed for the pig waste cultivation, operated under LED (0.127gL-1d-1) was similar to those attained for the Bristol media after 8 and 12 days (0.130 and 0.129 gL-1d-1 using Fluorescent and LED lights, respectively). The Chlorophyll content was correlated to FL3 autofluorescence, with R2>0.97 for Bristol and R2>0.92 for pig waste cultures. Regarding cell size and complexity, Bristol cultures did not show significant differences along time, while cells grown on pig waste increased, attaining FSC and SSC values similar to those observed for Bristol cultures. However, pig waste led to higher percentage of cells with permeabilised membrane (up to 18%) than Bristol cultures (7%). For pig waste experiments, ammonium removal rates were 95% with final values within legal limits. S. obliquus cultivations proved to be an efficient system for direct piggery effluent bioremediation, attaining biomass productivities similar to those obtained in synthetic media. Using LED lighting enables to reduce the energy consumption while maintaining microalgae growth and bioremediation performance. Scale-up to an outdoor 150L photobioreactor is underway.

EXCITON ENGINEERING THROUGH TUNALBLE FLUORESCENT QUANTUM DEFECTS

This thesis demonstrates exciton engineering in semiconducting single-walled carbon nanotubes through tunable fluorescent quantum defects. By introducing different functional moieties on the sp2 lattice of carbon nanotubes, the nanotube photoluminescence is systematically tuned over 68 meV in the second near-infrared window. This new class of quantum emitters is enabled by a new chemistry that allows covalent attachment of alkyl/aryl functional groups from their iodide precursors in aqueous solution. Using aminoaryl quantum defects, we show that the pH and temperature of complex fluids can be optically measured through defect photoluminescence that encodes the local environment information. Furthermore, defect-bound trions, which are electron-hole-electron tri-carrier quasi-particles, are observed in alkylated single-walled carbon nanotubes at room temperature with surprisingly high photoluminescence brightness. Collectively, the emission from defect-bound excitons and trions in (6,5)-single walled carbon nanotubes is 18-fold brighter than that of the native exciton. These findings pave the way to chemical tailoring of the electronic and optical properties of carbon nanostructures with fluorescent quantum defects and may find applications in optoelectronics and bioimaging.

Study of led lamps technologies impact on the utility

With the growing interest in the issue of reducing powerconsumption in electricity applications, energy-saving devises and the problem of their operation gains more attention. The increase in the utilization of energy-saving lamps, especially LED lamps, leads to the wide interest in their influence on the power system. The impact of discussed devices on the voltage and current in the grid must be thoroughly studied before launching devices into the market. The studies undertaken on the LED lamps present in a wide range the issue of harmonic emission from lamps and their influence on power quality. Due to many anufacturing technologies, different LED devices can have various effects on the utility. It is significant to carry out researches concerning the adverse effects of energy-saving lamps in order to utilize devices that meet certain requirements which are set by the international commissions.