Search results for "Pori"
showing 10 items of 761 documents
Lactones from the Sponge-Derived Fungus Talaromyces rugulosus.
2017
The marine-derived fungus Talaromyces rugulosus isolated from the Mediterranean sponge Axinella cannabina and cultured on solid rice medium yielded seventeen lactone derivatives including five butenolides (1–5), seven (3S)-resorcylide derivatives (6–12), two butenolide-resorcylide dimers (13 and 14), and three dihydroisocoumarins (15–17). Among them, fourteen compounds (1–3, 6–16) are new natural products. The structures of the isolated compounds were elucidated by 1D and 2D NMR (Nuclear Magnetic Resonance) spectroscopy as well as by ESI-HRMS (ElectroSpray Ionization-High Resolution Mass Spectrometry). TDDFT-ECD (Time-Dependent Density Functional Theory-Electronic Circular Dichroism) calcul…
Cladosporinone, a new viriditoxin derivative from the hypersaline lake derived fungus Cladosporium cladosporioides
2015
A new cytotoxic viriditoxin derivative, cladosporinone (1), along with the known viriditoxin (2) and two viriditoxin derivatives (3 and 4) were obtained from the fungus C ladosporium cladosporioides isolated from the sediment of a hypersaline lake in Egypt. The structure of the new compound (1) was determined by 1D and 2D NMR measurements as well as by high-resolution ESIMS and electronic circular dichroism spectroscopy. All isolated compounds were studied for their cytotoxicity against the murine lymphoma cell line L5187Y and for their antibiotic activity against several pathogenic bacteria. Viriditoxin (2) was the most active compound in both bioassays. Compound 1 also exhibited strong cy…
Comparison of several methods used for the determination of cephalosporins. Analysis of cephalexin in pharmaceutical samples
2002
The precision of UV absorbance of intact and acid degraded cephalosporins, ninhydrin, high performance liquid chromatography and iodometric methods used for analysis of cefoxitin, cefotaxime, cephazolin and cephalexin were compared. To obtain the calibration graphs the analytical signal used were: absorbance, first derivative absorbance, second derivative absorbance and H-point Standard Additions Method by using absorbance values at two selected wavelengths as analytical signal. These methods and calibration graphs were also used for the determination of cephalexin in pharmaceutical samples.
Identification and isolation of the primary aggregation factor from the cell membrane of the sponge Geodia cydonium
1985
The primary aggregation factor (pAF) of sponge cells is a glycoprotein that is firmly associated with the cell membrane. Polyspecific antibodies (anti-GM) prepared from sera raised against membranes of cells from the siliceous sponge Geodia cydonium were found to inhibit initial aggregation of homologous cells. The inhibition of aggregation, caused by anti-GM was neutralized by pAF. The pAF had been successfully solubilized and enriched by affinity chromatography, gel filtration and density gradient centrifugation, if checked by polyacrylamide gel electrophoresis in the presence of urea. The Mr of the native pAF was approximately 40 000 as estimated by gel filtration; under denaturing condi…
Cloning and expression of the sponge longevity gene SDLAGL.
2000
Porifera show a characteristic Bauplan in spite of the fact that (almost) all cells are telomerase-positive and presumably provided with an unlimited potency for cell proliferation. One gene, SDLAGL, was identified in the marine sponge Suberites domuncula whose deduced polypeptide showed high sequence similarity to the longevity assurance genes from other Metazoa. While in single cells no transcripts of SDLAGL could be identified, high expression was seen after re-aggregation of single cells and in proliferating cells of primmorphs.
Evolutionary analysis of G-proteins in early metazoans: Cloning of α- and β-subunits from the sponge Geodia cydonium1The sequences reported here have…
1998
G-protein-coupled (seven-transmembrane segment)-receptors represent a major group of metazoan receptors, involved in transduction of extracellular signals. The G-proteins, which are made up of Galpha/beta/gamma-subunits, link the receptors to the effector system(s). To analyze the phylogenetic relationships among the metazoan alpha-subunits of G-proteins, cDNAs of alpha-subunits were isolated from Geodia cydonium, a marine sponge belonging to the lowest metazoan phylum, Porifera. One encodes a putative isotype of a stimulator of the adenylyl cyclase (Galpha s), another one a putative inhibitor of the adenylyl cyclase (Galpha i/o) and the third one a putative activator of phospholipase C (Ga…
Le Cycle des Myxozoa et les Cnidaires: comparaison des formes planctoniques
2007
Les études moléculaires rapprochent désormais les Myxozoaires des Cnidaires. Les deux groupes sont présents exclusivement en milieu aquatique et utilisent l’eau comme vecteur de prolifération et de dissémination Au cours de leur cycle de vie, les Cnidaires passent d’une phase sessile fixée sur des substrats, la forme Polype, à une phase libre autonome ou planctonique, la forme méduse et planula. Chez les Myxozoa on observe aussi une phase planctonique à morphologie actinomyxidie issue de la reproduction sexuée chez un annélide et une phase non planctonique à morphologie myxosporidie produite par reproduction sexuée chez le poisson. Toutefois, les connaissances sur la sexualité des Cnidaires…
Conflict between parasites with different transmission strategies infecting an amphipod host
2005
Competition between parasites within a host can influence the evolution of parasite virulence and host resistance, but few studies examine the effects of unrelated parasites with conflicting transmission strategies infecting the same host. Vertically transmitted (VT) parasites, transmitted from mother to offspring, are in conflict with virulent, horizontally transmitted (HT) parasites, because healthy hosts are necessary to maximize VT parasite fitness. Resolution of the conflict between these parasites should lead to the evolution of one of two strategies: avoidance, or sabotage of HT parasite virulence by the VT parasite. We investigated two co-infecting parasites in the amphipod host, G…
Physicochemical and functional characterization of the polymerization process of the Geodia cydonium lectin
1985
The extracellularly localized, galactose-specific lectin from the sponge Geodia cydonium binds at one class of sites, 40 mol Ca2+/mol lectin with an association constant (Ka) of 0.3 X 10(6)M-1. Stoichiometric calculations reveal that in the extracellular milieu 22 mol Ca2+ (maximum) are complexed per mol lectin. Binding of Ca2+ to the lectin increases its apparent Mr from 44000 to 56000 (electrophoretic determination) or from 36500 to 53500 (high-pressure liquid gel chromatographical determination); the s20, w increases from 4.3 S to 4.5 S if Ca2+ is added to the lectin. In the presence of Ca2+ the lectin undergoes a conformational change perhaps by expanding the carbohydrate side chains wh…
Application of Cell Culture for the Production of Bioactive Compounds from Sponges: Synthesis of Avarol by Primmorphs from Dysidea avara
2000
Among all metazoan phyla, sponges are known to produce the largest number of bioactive compounds. However, until now, only one compound, arabinofuranosyladenine, has been approved for application in humans. One major obstacle is the limited availability of larger quantities of defined sponge starting material. Recently, we introduced the in vitro culture of primmorphs from Suberites domuncula, which contain proliferating cells. Now we have established the primmorph culture also from the marine sponge Dysidea avara and demonstrate that this special form of sponge cell aggregates produces avarol, a sesquiterpenoid hydroquinone, known to display strong cytostatic activity especially against ma…