3,673 research outputs found

    Traditional and Modern Biomedical Prospecting: Part I—the History: Sustainable Exploitation of Biodiversity (Sponges and Invertebrates) in the Adriatic Sea in Rovinj (Croatia)

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    Nature, especially the marine environment, provides the most effective drugs used in human therapy. Among the metazoans, the marine sponges (phylum Porifera), which are sessile filter feeders, produce the most potent and highly selective bioactive secondary metabolites. These animals (or their associated symbiotic microorganisms) synthesize secondary metabolites whose activity and selectivity has developed during their long evolutionary history (evochemistry). The exploitation of these resources has become possible due to the progress in molecular and cell biology. BIOTECmarin, the German Center of Excellence follows this rationale. In the past, these animals have been successfully and extensively utilized to isolate bioactive compounds and biomaterials for human benefit. Pharmaceuticals prepared from marine animals, primarily sponges, have been applied since ancient times (Hippocrates, Aristotle and later Plinius). It has been reported that extracts and/or components from sponges can be used for the treatment of specific diseases. For a systematic and applied-oriented exploitation, the successful development of effective compounds largely depends on quality of the institutional infrastructure of marine stations and more so on the biodiversity. The Center for Marine Research in Rovinj (Croatia) fulfils these prerequisites. Founded in 1891, this institute has to its credit major discoveries related to exploitation of secondary metabolites/biomaterials from sponges for therapeutical application and to obtain biomaterials for general wellbeing. This is the first part of a review focusing on biomedical prospecting. Here, we have mainly described the historic background. The details of techniques, substances, approaches and outlooks will be discussed in the second part

    Protein SRP54 iz morske spužve Geodia cydonium

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    In the systematic search for phylogenetically conserved proteins in the simplest and most ancient extant metazoan phylum – Porifera, we have identified and analyzed a cDNA encoding the signal recognition particle 54 kD protein (SRP54) from the marine sponge Geodia cydonium (Demospongiae). The signal recognition particle (SRP) is a universally conserved ribonucleoprotein complex of a very ancient origin, comprising SRP RNA and several proteins (six in mammals). The nucleotide sequence of the sponge cDNA predicts a protein of 499 amino acid residues with a calculated Mr of 55175. G. cydonium SRP54 displays unusually high overall similarity (90 %) with human/mammalian SRP54 proteins, higher than with Drosophila melanogaster (88 %), or Caenorhabditis elegans (82 %). The same was found for the majority of known and phylogenetically conserved proteins from sponges, indicating that the molecular evolutionary rates in protein coding genes in Porifera as well as in highly developed mammals (vertebrates) are slower, when compared with the rates in homologous genes from invertebrates (insects, nematodes). Therefore, genes/proteins from sponges might be the best candidates for the reconstruction of ancient structures of proteins and genome/proteome complexity in the ancestral organism, common to all multicellular animals.U sistematskoj potrazi za filogenetski sačuvanim proteinima u spužava, najjednostavnijih i najstarijih živućih Metazoa, autori su identificirali i analizirali cDNA koja kodira protein SRP54 u morske spužve Geodia cydonium. SRP54 je evolucijski najsačuvaniji protein ribonukleoproteinskoga kompleksa SRP (signal recognition particle), odgovornog za translokaciju sekretornih i transmembranskih proteina. SRP je nastao vrlo rano u evoluciji i svugdje je prisutan u živom svijetu, od bakterija do čovjeka. cDNA spužve G. cydonium kodira protein SRP54 dug 499 aminokiselina, izračunate molekularne mase 55175, koji pokazuje najviši stupanj sličnosti (90 %) s ljudskim proteinom SRP54, više nego sa SRP54 iz kukca Drosophila melanogaster (88 %) ili oblića Caenorhabditis elegans (82 %). Velika sličnost proteina spužava s homolozima u sisavaca uočena u ovom radu, kao i u našim prijašnjim istraživanjima, upućuje na sporije evolucijske promjene u genima spužava i sisavaca (kralježnjaka) u usporedbi s ubrzanijim promjenama u genima kukaca i oblića (beskralježnjaka). Geni/proteini spužava su stoga posebno korisni za rekonstrukciju strukture proteina i kompleksnosti genoma/proteoma u ancestralnom organizmu koji je bio zajednički predak svih višestaničnih životinja

    Reactions at polymer interfaces: A Monte Carlo Simulation

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    Reactions at a strongly segregated interface of a symmetric binary polymer blend are investigated via Monte Carlo simulations. End functionalized homopolymers of different species interact at the interface instantaneously and irreversibly to form diblock copolymers. The simulations, in the framework of the bond fluctuation model, determine the time dependence of the copolymer production in the initial and intermediate time regime for small reactant concentration ρ0Rg3=0.163...0.0406\rho_0 R_g^3=0.163 ... 0.0406. The results are compared to recent theories and simulation data of a simple reaction diffusion model. For the reactant concentration accessible in the simulation, no linear growth of the copolymer density is found in the initial regime, and a t\sqrt{t}-law is observed in the intermediate stage.Comment: to appear in Macromolecule

    Dvije nukleozid-difosfat kinaze (NDPK/Nm23) iz morske spužve Suberites domuncula

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    Suberites domuncula is a member of the most ancient and simplest extant phylum of multicellular animals – sponges (Porifera). A database of S. domuncula expressed sequence tags (ESTs) was recently constructed by random cDNA sequencing. Two NDPK/Nm23 proteins from the sponge Suberites domuncula are reported here. Sponge proteins were named Nm23-SD1 and Nm23-SD6, because they display the highest sequence similarity with human Nm23-H1 and -H6 proteins. Overall sequence conservation of Nm23-SD1 with human Nm23-H1 is very high – 79 % (71 % identical amino acids). Nm23-SD6 possesses an insertion at the C-terminus and displays 55 % overall homology (40 % identical amino acids) with human Nm23 H6. Secondary structure predictions for both sponge and human Nm23 protein pairs are almost identical. S. domuncula Nm23 proteins display high similarity to homologues from mammals/humans, higher than to e.g. NDPK/Nm23 proteins from Drosophila or other invertebrates. Sponge Nm23 proteins are more similar to mammalian/human Nm23 proteins than most known Nm23 proteins of invertebrates.Suberites domuncula je pripadnik najstarije i najjednostavnije postojeće skupine (koljena) višestaničnih životinja – spužvi (Porifera). Nasumičnim sekvenciranjem cDNA S. domuncula nedavno je konstruirana baza EST-ova (expressed sequence tags). U ovom radu opisana su dva NDPK/Nm23 proteina iz spužve Suberites domuncula. Spužvini proteini nazvani su Nm23-SD1 i Nm23-SD6 jer su po aminokiselinskim sljedovima najslič niji ljudskim Nm23-H1 i -H6 proteinima. Ukupna sačuvanost sekvence izme|u Nm23-SD1 i Nm23-H1 vrlo je visoka i iznosi 79 % (71 % je identična). Nm23-SD6 ima inserciju na C-kraju i pokazuje ukupnu homologiju od 55 % (40 % identičnosti) s ljudskim Nm23-H6. Predikcija sekundarne strukture pokazuje da su oba proteinska para gotovo jednaka. Nm23 proteini iz spužve S. domuncula pokazuju visoku sličnost s homolozima iz sisavaca/čovjeka, višu nego s npr. NDPK/Nm23 proteinima iz vinske mušice ili drugih beskralješnjaka. Osim toga, sličniji su proteinima iz sisavaca/čovjeka od većine poznatih Nm23 proteina iz beskralješnjak

    Isolation and Characterization of Adhesive Secretion from Cuvierian Tubules of Sea Cucumber Holothuria forskåli (Echinodermata: Holothuroidea)

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    The sea cucumber Holothuria forskåli possesses a specialized system called Cuvierian tubules. During mechanical stimulation white filaments (tubules) are expelled and become sticky upon contact with any object. We isolated a protein with adhesive properties from protein extracts of Cuvierian tubules from H. forskåli. This protein was identified by antibodies against recombinant precollagen D which is located in the byssal threads of the mussel Mytilus galloprovincialis. To find out the optimal procedure for extraction and purification, the identified protein was isolated by several methods, including electroelution, binding to glass beads, immunoprecipitation, and gel filtration. Antibodies raised against the isolated protein were used for localization of the adhesive protein in Cuvierian tubules. Immunostaining and immunogold electron microscopical studies revealed the strongest immunoreactivity in the mesothelium; this tissue layer is involved in adhesion. Adhesion of Cuvierian tubule extracts was measured on the surface of various materials. The extracted protein showed the strongest adhesion to Teflon surface. Increased adhesion was observed in the presence of potassium and EDTA, while cadmium caused a decrease in adhesion. Addition of antibodies and trypsin abolished the adhesive properties of the extract

    The largest Bio-Silica Structure on Earth: The Giant Basal Spicule from the Deep-Sea Glass Sponge Monorhaphis chuni

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    The depth of the ocean is plentifully populated with a highly diverse fauna and flora, from where the Challenger expedition (1873–1876) treasured up a rich collection of vitreous sponges [Hexactinellida]. They have been described by Schulze and represent the phylogenetically oldest class of siliceous sponges [phylum Porifera]; they are eye-catching because of their distinct body plan, which relies on a filigree skeleton. It is constructed by an array of morphologically determined elements, the spicules. Later, during the German Deep Sea Expedition “Valdivia” (1898-1899), Schulze could describe the largest siliceous hexactinellid sponge on Earth, the up to 3 m high Monorhaphis chuni, which develops the equally largest bio-silica structures, the giant basal spicules (3 m × 10 mm). With such spicules as a model, basic knowledge on the morphology, formation, and development of the skeletal elements could be elaborated. Spicules are formed by a proteinaceous scaffold which mediates the formation of siliceous lamellae in which the proteins are encased. Up to eight hundred 5 to 10 μm thick lamellae can be concentrically arranged around an axial canal. The silica matrix is composed of almost pure silicon and oxygen, providing it with unusual optophysical properties that are superior to those of man-made waveguides. Experiments indicated that the spicules function in vivo as a nonocular photoreception system. In addition, the spicules have exceptional mechanical properties, combining mechanical stability with strength and stiffness. Like demosponges the hexactinellids synthesize their silica enzymatically, via the enzyme silicatein. All these basic insights will surely contribute also to a further applied utilization and exploration of bio-silica in material/medical science

    Comparison between the Comet Assay and Fast Micromethod® for Measuring DNA Damage in HeLa Cells

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    The sensitivity and precision of the single cell gel electrophoresis (Comet) assay and Fast Micromethod® for DNA damage determinations in human HeLa cell line were compared. The first assay allows analysis of DNA breaks in individual cells while the second is a rapid and convenient procedure for DNA breaks determination in cell suspensions on single microplates. Both assays detect DNA strand breaks, alkali-labile sites and transient breaks occurring at sites of ongoing repair and might be applied for the assessment of surface water genotoxic potential as well as for clinical use. DNA damage in HeLa cells was induced by different doses of γ-rays generated by Cs137 (8 to 500 cGy), UV-C light (10 to 1000 J m-2) and by different concentrations of 4-nitroquinoline-V-oxide (0.026-2.6 μmol dm-3). Gamma rays induced a dose-depended response with the average Comet tail moment values from 7 mm for the negative control to 291 mm for 200 cGy, from 6.1 to 192 mm for 500 J m-2 of UV-C light and from 7.1 to 238 mm for 1.0 μmol dm-3 of 4-nitro-quinoline-N-oxide. The Fast Micromethod® strand scission factor varied from 0.010 for negative control to 0.701 for 500 cGy, from 0.019 to 1.196 for 1000 J m-2 and from 0.003 to 0.810 for 0.5 μmol dm-3 of 4-nitroquinoline-IV-oxide. Sensitivity was the same for both methods and in the case of 4-nitroquinoline-IV-oxide even better precision (lower variation coefficient) was achieved with the Fast Micromethod®. Since the time required for multiple analysis by the Fast Micromethod® is short (2 hours or less), its use in measuring DNA breakage in cells can be recommended for environmental genotoxicity monitoring

    Mumijo Traditional Medicine: Fossil Deposits from Antarctica (Chemical Composition and Beneficial Bioactivity)

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    Mumijo is a widely used traditional medicine, especially in Russia, Altai Mountains, Mongolia, Iran Kasachstan and in Kirgistan. Mumijo preparations have been successfully used for the prevention and treatment of infectious diseases; they display immune-stimulating and antiallergic activity as well. In the present study, we investigate the chemical composition and the biomedical potential of a Mumijo(-related) product collected from the Antarctica. The yellow material originates from the snow petrels, Pagodroma nivea. Extensive purification and chemical analysis revealed that the fossil samples are a mixture of glycerol derivatives. In vitro experiments showed that the Mumijo extract caused in cortical neurons a strong neuroprotective effect against the apoptosis-inducing amyloid peptide fragment β-fragment 25–35 (Aβ25–35). In addition, the fraction rich in glycerol ethers/wax esters displayed a significant growth-promoting activity in permanent neuronal PC12 cells. It is concluded that this new Mumijo preparation has distinct and marked neuroprotective activity, very likely due to the content of glycerol ether derivatives

    Porifera Lectins: diversity, physiological roles and biotechnological potential

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    An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest

    Tajixanthonhydrat und dessen Verwendung zur Behandlung von Tumorerkrankungen

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    Es werden Tajixanthonhydrat sowie Tajixanthonhydrat-Derivate der allgemeinen Formel I $F1 beschrieben sowie ein Verfahren zu ihrer Herstellung. Tajixanthonhydrat besitzt u. a. eine ausgeprägte Biofilm-inhibierende Wirkung gegen Staphylococcus epidermidis
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