Cloning and expression of ATP N-glycosidase from the freshwater sponge Ephydatia muelleri.

Previously we had discovered unusual enzymatic activity in the marine sponge Axinella polypoides, ATP N-glycosidase (Reintamm et al., 2003). We show here that the Ephydatia muelleri mRNA encoding protein with PNP_UDP_1 (phosphorylase superfamily) signature is the secreted ATP N-glycosidase.

Identification of a novel member of 2H phosphoesterases, 2',5'-oligoadenylate degrading ribonuclease from the oyster Crassostrea gigas.

Several genes of IFN-mediated pathways in vertebrates, among them the genes that participate in the 2',5'-oligoadenylate synthetase (OAS)/RNase L pathway, have been identified in C. gigas. In the present study, we identified genes, which encode proteins having 2',5'-oligoadenylate degrading activity in C.

Enzymatically active 2',5'-oligoadenylate synthetases are widely distributed among Metazoa, including protostome lineage.

2',5'-Oligoadenylate synthetases (OASs) belong to the nucleotidyl transferase family together with poly(A) polymerases, CCA-adding enzymes and the recently discovered cyclic-GMP-AMP synthase (cGAS). Mammalian OASs have been thoroughly characterized as components of the interferon-induced antiviral system. The OAS activity and the respective genes were also discovered in marine sponges where the interferon system is absent.

A novel endoribonuclease from the marine sponge Tethya aurantium specific to 2',5'-phosphodiester bonds.

In the marine sponge Tethya aurantium a novel endoribonuclease was found which specifically catalyzed the degradation of 2',5'-phosphodiester linkages and was therefore named endo-2',5'-ribonuclease. This enzymatic reaction yielded 2',3'-cyclic phosphate and 5'-OH products similarly to the 3'-5' bond cleavage in RNA, catalyzed by metal-independent ribonucleases. The partially purified enzyme preparation was used for its biochemical characterization.

Expressed 2-5A synthetase genes and pseudogenes in the marine sponge Geodia barretti.

The 2',5'-oligoadenylate synthetases (2-5A synthetases, OAS) form a family of proteins presented in many branches of Metazoa. The phylum Porifera (sponges) contains OAS proteins which are different from those in vertebrates and form a distinct OAS subfamily. In turn, OAS proteins from different genera of Demospongia show rather low similarities in their primary structures.

Natural occurrence of 2',5'-linked heteronucleotides in marine sponges.

2',5'-oligoadenylate synthetases (OAS) as a component of mammalian interferon-induced antiviral enzymatic system catalyze the oligomerization of cellular ATP into 2',5'-linked oligoadenylates (2-5A). Though vertebrate OASs have been characterized as 2'-nucleotidyl transferases under in vitro conditions, the natural occurrence of 2',5'-oligonucleotides other than 2-5A has never been demonstrated. Here we have demonstrated that OASs from the marine sponges Thenea muricata and Chondrilla nucula are able to catalyze in vivo synthesis of 2-5A as well as the synthesis of a series 2',5'-linked heteronucleotides which accompanied high levels of 2',5'-diadenylates.

Sponge OAS has a distinct genomic structure within the 2-5A synthetase family.

2',5'-Oligoadenylate synthetases (2-5A synthetases, OAS) are enzymes that play an important role in the interferon-induced antiviral defense mechanisms in mammals. Sponges, the evolutionarily lowest multicellular animals, also possess OAS; however, their function is presently unclear. Low homology between primary structures of 2-5A synthetases from vertebrates and sponges renders their evolutionary relationship obscure.

Expression and characterization of recombinant 2',5'-oligoadenylate synthetase from the marine sponge Geodia cydonium.

2',5'-oligoadenylate (2-5A) synthetases are known as components of the interferon-induced cellular defence mechanism in mammals. The existence of 2-5A synthetases in the evolutionarily lowest multicellular animals, the marine sponges, has been demonstrated and the respective candidate genes from Geodia cydonium and Suberites domuncula have been identified. In the present study, the putative 2-5A synthetase cDNA from G.

A novel metalloprotease from Vipera lebetina venom induces human endothelial cell apoptosis.

A novel endothelial cell apoptosis inducing metalloprotease (VLAIP) was found in the snake venom of Vipera lebetina. This metalloprotease is a heterodimeric glycoprotein with molecular mass of about 106 kDa. The protease hydrolyzes azocasein, fibrinogen and oxidized insulin B-chain.

ATP N-glycosidase - a novel ATP-converting activity from a marine sponge Axinella polypoides.

A novel nucleosidase enzymatic activity was discovered in the marine sponge Axinella polypoides. This enzyme, designated as ATP N-glycosidase, converts adenosine-5'-triphosphate into adenine and ribose-5-triphosphate. The crude extract of A.

Qualitative and quantitative aspects of 2-5A synthesizing capacity of different marine sponges.

2-5A synthetase is an important component of the mammalian antiviral 2-5A system. At present, the existence of 2-5A synthetase in the lowest animals, the marine sponges, has been demonstrated, although this enzyme has not been found in bacteria, yeast or plants. Here, we studied the 2-5A synthesizing capacity and the product profile of a variety of marine sponges belonging to Demospongia subclasses Tetractinomorpha and Ceractinomorpha.

Sponge (2',5')oligoadenylate synthetase activity in the whole sponge organism and in a primary cell culture.

A high (2',5')oligoadenylate (2-5A) synthetase activity was found in the marine sponge Geodia cydonium. Here we demonstrate that the 2-5A synthetase activity is present also in other sponge species although the level of the 2-5A synthetase activity varies in several magnitudes in different sponges. The 2-5A synthesizing activity was maintained in the primary culture produced from a sponge.

2',5'-oligoadenylate synthetase from a lower invertebrate, the marine sponge Geodia cydonium, does not need dsRNA for its enzymatic activity.

Recently, the presence of 2',5'-linked oligoadenylates and a high 2',5'-oligoadenylate synthetase activity were discovered in a lower invertebrate, the marine sponge Geodia cydonium. It has been demonstrated that mammalian 2-5A synthetase isozymes require a dsRNA cofactor for their enzymatic activity. Our results show that, unlike mammalian 2-5A synthetases, the 2-5A synthetase from the sponge acts in a dsRNA-independent manner in vitro.

Expression and activity of 2-5A synthetase in the course of differentiation and apoptosis of PC12 cells.

The role of IFN-induced 2-5A system in cell differentiation has not been elucidated. While studying differentiation of PC12 cells we found that the simultaneous treatment of cells with NGF and IFN-gamma in serum-containing medium resulted first in the extension of neurites and then apoptosis. On the contrary, in serum-free medium the cells underwent a more rapid neuronal differentiation.

The effect of 9,11-secosterol, a newly discovered compound from the soft coral Gersemia fruticosa, on the growth and cell cycle progression of various tumor cells in culture.

A new 9,11-secosterol, 24-nor-9,11-seco-11-acetoxy-3 beta,6 alpha-dihydroxycholest-7,22(E)-dien-9-one, was found to exhibit growth inhibitory (IC50 below 10 microM) and cytotoxic activities against human leukemia K562, human cervical cancer HeLa, and Ehrlich ascites tumor cells in vitro. The cytostatic concentrations of the compound generally caused the G2/M block in the cell cycle progression, but differences between the three tumor cell lines in the events leading to cell death were remarkable. While inhibiting cell proliferation, 9,11-secosterol caused accumulation of HeLa and K562 cells in the metaphase of mitosis.

Comparative fluorometric study of benzo(a)pyrene and aza-aromatic hydrocarbon penetration and metabolism kinetics in the skin of hairless mice.

The kinetics of penetration and metabolism of BaP, BACs, DB(a,h)ACs and DB(c,g)Cs in the skin of hairless mice was studied. The relative fluorescence intensities were measured during three hours after applying 10 nmoles of the compound to the interscapular region of the mice. By using a kinetical model which combines a non-steady diffusion of a hydrocarbon through the stratum corneum and the metabolic oxidation by epidermal cells, the rate constants for the two processes were calculated.

[Synthesis and antiaggregation activity of prostacyclin analogs. II. Direct synthesis of 15-fluoro-13,14-didehydrocarbacyclin].

E- and Z-isomers of 15-fluoro-13,14-dehydrocarbacyclin were synthesized starting from 2,3-epoxy-bicyclo[3.3.0]octan-6-one ethylene ketal with the use of 3-fluoro-1-octynydlithium.

[Synthesis and antiaggregation activity of prostacyclin analogs. 1. Bicyclo [3.2.0] heptane analogs].

Bicyclo[3.2.0]heptane analogues of prostacyclin were synthesized starting from 2,3-epoxy-bicyclo[3.

Identification and biological activity of a novel natural prostaglandin, 5,6-dihydro-prostaglandin E3.

A novel natural E-prostaglandin was detected by HPLC among the endogenous prostaglandins extracted from ram seminal vesicles. The corresponding precursor - all-cis-eicosa-8, 11, 14, 17-tetraenoic acid was isolated from bovine liver lipids and the preparative biosynthesis with the microsomal fraction of ram seminal vesicles was performed. The isolated product was purified by HPLC and identified by GC-MS as 5,6-dihydro-PGE3.

Fluorescence method for the measurement of penetration and metabolism of carcinogens in mouse skin.

The present study aims at elucidating by fluorescence measurements the possibilities of the mathematical description of the processes of penetration and metabolism of carcinogenic polynuclear arenes in mouse skin. The fluorescence intensities of the topically applied benzo(a)pyrene (BaP), 10-60 nmoles of BaP in 100 microliters of acetone, were measured in the interscapular region of hairless mice during three hours. A kinetic model combining a non-steady diffusion of BaP through the stratum corneum and BaP metabolic oxidation by epidermal cells was elaborated.

[Kinetics of benzo[a]pyrene penetration into the mouse skin after treatment with various phenols].

A mathematical method for the study of benzo(a)pyrene (BP) penetration into the skin of nude mice was elaborated and supported by the experimental data. BP, whose concentration was measured by its fluorescence intensity, was applied to the skin using a "dry" technique. The effect of certain phenols and products of oxybenzene oxidation was studied.

[The effect of hydroxymethyl derivatives of 7,12-dimethylbenz(a)anthracene on its metabolism and toxic action in tissue culture].

The naturally occurring hydroxymethyl derivatives of the carcinogen 7,12-dimethylbenz(a)anthracene was found to inhibit the metabolic hydroxylation and toxic effect of this carcinogen in mouse embryo fibroblast-like cell culture. The greatest reduction of both effects was obtained when 12-hydroxymethyl-7-methylbenz(a)anthracene was added to the growth medium, less effective were, resp., 7,12-dihydroxymethylbenz(a)-anthracene and 7-hydroxymethyl-12-methylbenz(a)anthracene.

[Effect of metabolites of 7,12-dimethylbenz(a)anthracene on the dynamics of its fluorescence in the skin of hairless mice].

The influence of two metabolites of 7,12-dimethylbenz(a)anthracene (DMBA)--7-hydromethyl-12-methylbenz(a)anthracene and 7,12-dihydroxymethylbenz(a)anthracene--on the dynamics of DMBA fluorescence was studied in the skin of mice. The first of the metabolites did not affect the dynamics of DMBA fluorescence, whereas the second one, when used in equimolar concentrations with DMBA, prolonged the duration of DMBA fluorescence in the skin. The same effect was observed in case of 7,8-benzoflavone, and inhibitor of DMBA metabolism.