516 research outputs found

    Differential Gene Expression at Coral Settlement and Metamorphosis - A Subtractive Hybridization Study

    Get PDF
    A successful metamorphosis from a planktonic larva to a settled polyp, which under favorable conditions will establish a future colony, is critical for the survival of corals. However, in contrast to the situation in other animals, e.g., frogs and insects, little is known about the molecular basis of coral metamorphosis. We have begun to redress this situation with previous microarray studies, but there is still a great deal to learn. In the present paper we have utilized a different technology, subtractive hybridization, to characterize genes differentially expressed across this developmental transition and to compare the success of this method to microarray.\ud \ud Methodology/Principal Findings\ud \ud Suppressive subtractive hybridization (SSH) was used to identify two pools of transcripts from the coral, Acropora millepora. One is enriched for transcripts expressed at higher levels at the pre-settlement stage, and the other for transcripts expressed at higher levels at the post-settlement stage. Virtual northern blots were used to demonstrate the efficacy of the subtractive hybridization technique. Both pools contain transcripts coding for proteins in various functional classes but transcriptional regulatory proteins were represented more frequently in the post-settlement pool. Approximately 18% of the transcripts showed no significant similarity to any other sequence on the public databases. Transcripts of particular interest were further characterized by in situ hybridization, which showed that many are regulated spatially as well as temporally. Notably, many transcripts exhibit axially restricted expression patterns that correlate with the pool from which they were isolated. Several transcripts are expressed in patterns consistent with a role in calcification.\ud \ud Conclusions\ud \ud We have characterized over 200 transcripts that are differentially expressed between the planula larva and post-settlement polyp of the coral, Acropora millepora. Sequence, putative function, and in some cases temporal and spatial expression are reported

    Development of optical methods for real-time whole-brain functional imaging of zebrafish neuronal activity

    Get PDF
    Each one of us in his life has, at least once, smelled the scent of roses, read one canto of Dante’s Commedia or listened to the sound of the sea from a shell. All of this is possible thanks to the astonishing capabilities of an organ, such as the brain, that allows us to collect and organize perceptions coming from sensory organs and to produce behavioural responses accordingly. Studying an operating brain in a non-invasive way is extremely difficult in mammals, and particularly in humans. In the last decade, a small teleost fish, zebrafish (Danio rerio), has been making its way into the field of neurosciences. The brain of a larval zebrafish is made up of 'only' 100000 neurons and it’s completely transparent, making it possible to optically access it. Here, taking advantage of the best of currently available technology, we devised optical solutions to investigate the dynamics of neuronal activity throughout the entire brain of zebrafish larvae

    Spatio-temporal organisation of plasma membrane proteins in budding yeast

    Get PDF

    Whole-transciptome analysis of [psi+] budding yeast via cDNA microarrays

    Get PDF
    Introduction: Prions of yeast present a novel analytical challenge in terms of both initial characterization and in vitro manipulation as models for human disease research. Presently, few robust analysis strategies have been successfully implemented which enable the efficient study of prion behavior in vivo. This study sought to evaluate the utilization of conventional dual-channel cDNA microarrays for the surveillance of transcriptomic regulation patterns by the [PSI+] yeast prion relative to an identical prion deficient yeast variant, [psi-]. Methods: A data analysis and normalization workflow strategy was developed and applied to cDNA array images, yielded quality-regulated expression ratios for a subset of genes exhibiting statistical congruence across multiple experimental repetitions and nested hybridization events. The significant gene list was analyzed using classical analytical approaches including several clustering-based methods and singular value decomposition. To add biological meaning to the differential expression data in hand, functional annotation using the Gene Ontology as well as several pathway-mapping approaches was conducted. Finally, the expression patterns observed were queried against all publicly curated microarray data performed using S. cerevisiae in order to discover similar expression behavior across a vast array of experimental conditions. Results: These data collectively implicate a low-level of overall genomic regulation as a result of the [PSI+] state, where the maximum statistically significant degree of differential expression was less than ±1 Log2(FC) in all cases. Notwithstanding, the [PSI+] differential expression was localized to several specific classes of structural elements and cellular functions, implying under homeostatic conditions significant up or down regulation is likely unnecessary but possible in those specific systems if environmental conditions warranted. As a result of these findings additional work pertaining to this system should include controlled insult to both yeast variants of differing environmental properties to promote a potential [PSI+] regulatory response coupled with co-surveillance of these conditions using transcriptomic and proteomic analysis methodologies

    Telecommunication Systems

    Get PDF
    This book is based on both industrial and academic research efforts in which a number of recent advancements and rare insights into telecommunication systems are well presented. The volume is organized into four parts: "Telecommunication Protocol, Optimization, and Security Frameworks", "Next-Generation Optical Access Technologies", "Convergence of Wireless-Optical Networks" and "Advanced Relay and Antenna Systems for Smart Networks." Chapters within these parts are self-contained and cross-referenced to facilitate further study

    JuhukÔnnid translatsioonis

    Get PDF
    VĂ€itekirja elektrooniline versioon ei sisalda publikatsioone.Poomisvastus on vĂ”tmetĂ€htsusega adaptiivsete mehhanismide regulatsioonil, mis aitavad bakteritel ebasoodsaid keskkonnatingimusi ĂŒle elada. Soolekepikeses (Escherichia coli) on selles protsessis oluliseks ensĂŒĂŒmiks RelA, mis vastusena aminohappenĂ€ljale sĂŒnteesib signaalmolekuli (p)ppGpp. See signaalmolekul mĂ”jutab transkriptsiooni, translatsiooni ja rakkude jagunemist. Meie töötasime vĂ€lja ĂŒhe molekuli jĂ€lgimise mikroskoopia metoodika, mis vĂ”imaldab mÔÔta molekulide difusiooni rakus. Kasutasime seda metoodikat erineva kiirusega liikuvate molekulide kirjeldamiseks. Rakus vabalt difundeeruva valgu nĂ€iteks oli fluorestseeruv valk mEos2. Hoopis teistsuguste omadustega valguks osutus mitokondri membraanivalk Tom40, mille liikumine on ĂŒhte asukohta piiratud. RelA puhul tĂ€heldasime nii vabu, kiirelt difundeeruvaid molekule kui ka ribosoomile seondunud ja seetĂ”ttu aeglaselt liikuvaid molekule. Kombineerides ĂŒhe molekuli jĂ€lgimise tulemusi biokeemiliste andmetega, pakume vĂ€lja RelA valgu töötsĂŒkli mudeli. Kuhjuv (p)ppGpp pĂ”hjustab samuti RelA aktivatsiooni. Sellisel viisil tekib positiivse tagasisidestusega regulatsioonisĂŒsteem ja signaalmolekuli kontsentratsioon tĂ”useb kiiresti.The stringent response plays key role in the activation and regulation of the adaptive mechanisms that bacteria employ in order to accommodate to the adverse conditions. In E.coli the process is governed by the stringent factor RelA, transferring the amino-acid starvation signals by synthesize (p)ppGpp altering cell replication, transcription and translation. We have developed in vivo single-molecule tracking microscopy assay that allows us to track fast and slowly diffusive cytosolic (stringent factor RelA and free GFP variant mEos2) or membrane bound (mitochondrial membrane channel Tom40) proteins. The fluorescently labeled Tom40-Dendra2 complex in the mitochondrial membrane showed highly mobile but confined diffusion properties By combining biochemical and single-molecule microscopy approaches we have suggested different (p)ppGpp synthesizing mechanism from the standard hopping model where many (p)ppGpp molecules are produced upon dissociation of enzymatically active RelA from the ribosome and (p)ppGpp production is directly responsible for enhancement of the RelA enzymatic activity by positive feedback loop acting at the enzymatic level.

    Molecular Imaging

    Get PDF
    The present book gives an exceptional overview of molecular imaging. Practical approach represents the red thread through the whole book, covering at the same time detailed background information that goes very deep into molecular as well as cellular level. Ideas how molecular imaging will develop in the near future present a special delicacy. This should be of special interest as the contributors are members of leading research groups from all over the world
    • 

    corecore