Search results for "centri"
showing 10 items of 869 documents
Preparation of Native and Recombinant Light-Harvesting Chlorophyll-<I>a/b </I>Complex
2004
Procedures to isolate native light-harvesting chlorophyll-a/b complex (LHCIIb) and to reconstitute recombinant LHCIIb are described. Separation of trimeric from monomeric forms and free pigment by sucrose density-gradient ultracentrifugation can be applied to both native and reconstituted complexes. The preparations are characterized by their pigment composition, protein pattern, and spectral properties.
Chlorophyll b is involved in long-wavelength spectral properties of light-harvesting complexes LHC I and LHC II.
2001
AbstractChlorophyll (Chl) molecules attached to plant light-harvesting complexes (LHC) differ in their spectral behavior. While most Chl a and Chl b molecules give rise to absorption bands between 645 nm and 670 nm, some special Chls absorb at wavelengths longer than 700 nm. Among the Chl a/b-antennae of higher plants these are found exclusively in LHC I. In order to assign this special spectral property to one chlorophyll species we reconstituted LHC of both photosystem I (Lhca4) and photosystem II (Lhcb1) with carotenoids and only Chl a or Chl b and analyzed the effect on pigment binding, absorption and fluorescence properties. In both LHCs the Chl-binding sites of the omitted Chl species…
IM30 triggers membrane fusion in cyanobacteria and chloroplasts
2015
The thylakoid membrane of chloroplasts and cyanobacteria is a unique internal membrane system harbouring the complexes of the photosynthetic electron transfer chain. Despite their apparent importance, little is known about the biogenesis and maintenance of thylakoid membranes. Although membrane fusion events are essential for the formation of thylakoid membranes, proteins involved in membrane fusion have yet to be identified in photosynthetic cells or organelles. Here we show that IM30, a conserved chloroplast and cyanobacterial protein of approximately 30 kDa binds as an oligomeric ring in a well-defined geometry specifically to membranes containing anionic lipids. Triggered by Mg2+, membr…
A rapid and cost-efficient DMSO-based method for isolating DNA from cultured lichen photobionts
2010
We have developed a simple and fast procedure for the purification of PCR-quality DNA from cultured lichen photobionts. This new one-step method uses the solvent dimethyl sulfoxide (DMSO) combined with heat treatment to chemically breakdown algal and plant tissues. The DMSO-DNA extracts may be directly precipitated and purified by standard techniques in a total time of approximately 30 min. Compared to other DNA extraction protocols, the DMSO-based method suppresses the need for liquid nitrogen, any extraction buffer, grinding, phenol, and long incubation or centrifugation steps, thereby considerably reducing the possibility of contamination. In addition, minimal amounts of starting materia…
Protoplasts fromPodospora anserina: Isolation, purification, and transformation
1985
Protoplasts fromPodospora anserina mycelium were produced using the commercially available enzyme Novozym 234. Different parameters involved in protoplast isolation were analyzed in order to establish optimal conditions, and protoplast production was notably increased. For the purification of protoplasts, several techniques based on both centrifugation and filtration were assayed, with filtration yielding the best results. Regeneration of protoplasts was studied on different media and osmostic stabilizers, and about 80% regeneration was obtained. The good physiological condition of the protoplasts produced with this method is demonstrated by the lack of cell wall and high regeneration rate …
La sostenibilidad, un nuevo pensamiento. Intervención de José Vidal-Beneyto
2003
Número monográfico sobre "El nuevo horizonte de la Sostenibilidad". Fundación Santander Central Hispano.
A Classical Synthesis of the Collagen-like Peptides with the Sequence Z(GlyProPro)nOBut and their characterization with circular dichroism and ultrac…
1975
Oligopeptides with the sequence Z(GlyProPro)nOBut (n = 3–7) were synthesized along a clasical pathway. Generally long fragments were condensed in order to allow an easy separation of the products from the reactants. It is established by molecular weight determination and measurements of circular dichroism that the peptides form the collagen-like triple helix in methanol and that they assume the random coil conformation in dilute acetic acid. The circular dichroism spectra agree reasonably well with the corresponding spectra for (ProProGly)10 which was obtained by solid phase synthesis in another laboratory.
Isolation and characterization of haemoporin, an abundant haemolymph protein from Aplysia californica.
2003
In the present study, we show the isolation and characterization of the protein haemoporin, which constitutes the second most abundant protein fraction in the haemolymph of the marine gastropod Aplysia californica. Although Aplysia is commonly used to investigate the molecular basis of learning, not much is known about the proteins in its haemolymph, which is in contact with the neurons owing to the open circulatory system of molluscs. In the native state, haemoporin is a macromolecular complex forming a cylinder with a central solvent-filled pore. The native complex most probably is a homopentamer made up from 70 kDa subunits with a molecular mass of 360 kDa and a sedimentation coefficient…
URBAN RESILIENCE AND WASTE MANAGEMENT: PROPOSALS OF NEW INFRASTRUCTURES FOR URBAN AREAS AND BUILDINGS
2015
La produzione ingente di rifiuti, quale conseguenza di costumi di vita volti allo spreco, rende vulnerabili i sistemi urbani che possono essere sottoposti, in casi emergenziali, a pressioni eccezionali e incontrollate con situazioni prossime al collasso. Un’opportuna e corretta gestione integrata dei rifiuti contribuisce alla resilienza dei sistemi urbani. Perciò si rendono necessarie la pianificazione e la progettazione di nuovi servizi e l’individuazione/integrazione di spazi e dotazioni tecnologiche per incentivare la popolazione a effettuare la raccolta differenziata in modo corretto e costante. Si presentano gli esiti di uno studio svolto in un piccolo centro siciliano. Partendo dalle …
Edilizia abusiva a Favara. Analisi dell’insediamento e sviluppo del territorio
2007
Il Piano Regolatore Generale, strumento di fondamentale importanza per lo sviluppo di un centro urbano e del suo territorio, è ancora per diverse città siciliane un obiettivo da raggiungere. I dati provenienti dall'Assessorato Regionale al Territorio e Ambiente (A.R.T.A.) indicano una Sicilia decisamente indietro nella progettazione urbanistica. Nell'isola soltanto il 40,3% dei comuni hanno un piano regolatore vigente. La mancata approvazione degli strumenti urbanistici ha influito negativamente sui processi di urbanizzazione, spesso frammentari e disorganici. Le città si sono sviluppate senza una forma, un modello riconoscibile, alimentando nei cittadini una politica che ha preferito l’edi…