1,721,108 research outputs found
Il settore nautico, i porti turistici e le problematiche innovative
No full textIl capitolo contorna il settore della nautica da diporto, il ruolo, al suo interno, dei porti turistici e le principali innovazioni nelle formule d'offerta dei porti stessi
Strategies of ELISA development for pesticide detection
No full textThis review examines some of the most common problems generally faced during the development of immunoenzymatic assays. In particular, the criteria of hapten design either for the preparation of the immunogen or the immunoenzymatic assay reagent are discussed. Examples are given from work carried out for the detection of triazole fungicides, specifically, tetraconazole, hexaconazole, penconazole and propiconazole. It is concluded that ELISA performance with polyclonal antibody is mainly affected by 2 factors: the use of a coating conjugate characterized by a handle different in length and nature from that present in the immunizing conjugate, and by a low hapten/protein molar ratio
Elongation of the catalytic loop of Azotobacter vinelandii rhodanese changed selectivity from sulfur to phosphorus compounds as substrates
No full textThe human genome contains numerous genes whose protein products are unknown in terms of structure, interaction partner, expression, and function. To unravel the function of these orphan genes, it is of particular value to isolate native forms of protein and peptide products derived from these genes. From human blood ultrafiltrate, we characterized a novel gene-encoded, cysteine-rich, and cationic peptide that we termed liver-expressed antimicrobial peptide 2 (LEAP-2). We identified several circulating forms of LEAP-2 differing in their amino-terminal length, all containing a core structure with two disulfide bonds formed by cysteine residues in relative 1-3 and 2-4 positions. Molecular cloning of the cDNA showed that LEAP-2 is synthesized as a 77-residue precursor, which is predominantly expressed in the liver and highly conserved among mammals. This makes it a unique peptide that does not exhibit similarity with any known human peptide regarding its primary structure, disulfide motif, and expression. Analysis of the LEAP-2 gene resulted in the identification of an alternative promoter and at least four different splicing variants, with the two dominating transcripts being tissue-specifically expressed. The largest native LEAP-2 form of 40 amino acid residues is generated from the precursor at a putative cleavage site for a furin-like endoprotease. In contrast to smaller LEAP-2 variants, this peptide exhibited dose-dependent antimicrobial activity against selected microbial model organisms. LEAP-2 shares some characteristic properties with classic peptide hormones and it is expected that the isolation of this novel peptide will help to unravel its physiological role
Evidence that elongation of the catalytic loop of the Azotobacter vinelandii rhodanese changed selectivity from sulfur- to phosphate-containing substrates
No full textRecent investigations have shown that the rhodanese domains, ubiquitous structural modules which might represent an example of conserved structures with possible functional diversity, are structurally related to the catalytic subunit of Cdc25 phosphatase enzymes. The major difference characterizing the active-site of the Azotobacter vinelandii rhodanese RhdA, with respect to the closely related Cdc25s (A, B, C), is that in Cdc25 phosphatases the active site loop [His-Cys-(X)5-Arg] is one residue longer than in RhdA [His-Cys-(X)4-Arg]. According to the hypothesis that the length of the RhdA active-site loop should play a key role in substrate recognition and catalytic activity, RhdA scaffold was the starting point for producing mutants with single-residue insertion to generate the catalytic loop HCQTHAHR (in RhdA-Ala) and HCQTHSHR (in RhdA-Ser). Analyses of the catalytic performances of the engineered RhdAs revealed that elongation of the catalytic loop definitely compromised the ability to catalyze sulfur transfer reactions, while it generated 'phosphatase' enzymes able to interact productively with the artificial substrate 3-O-methylfluorescein phosphate. Although this study is restricted to an example of rhodanese modules (RhdA), it provided experimental evidence of the hypothesis that a specific mutational event (a single-residue insertion or deletion in the active-site loop) could change the selectivity from sulfur- to phosphate-containing substrates (or vice versa)
Desulfo-glucosinolate sulfotransferases isolated from several Arabidopsis thaliana ecotypes differ in their sequence and enzyme kinetics
Full text linkThe goal was to investigate whether the diverse glucosinolate (Gl) profiles described for different Arabidopsis thaliana (L.) Heynh. ecotypes are at least partially shaped by the kinetic properties of sulfotransferases (SOTs) (EC 2.8.2.-) catalyzing the final step in Gl core structure biosynthesis. This study focuses on only one of the three SOTs that contribute to Gl biosynthesis. Homologues of AtSOT18 proteins were characterized, which was inspired by earlier findings on SOTs from ecotypes Col-0 and C24 differing in two amino acids (aa) and specific enzyme activities. Could there be a correlation of AtSOT18 enzyme activities and differences in Gl profiles between the ecotypes? SOT18 sequences from eight Arabidopsis ecotypes with highly diverse Gl patterns differed in two aa at various positions in the protein sequence. The SOT18 sequence from Col-0 showed the highest similarity to the largest number of other sequences in the alignment. The small differences in the primary sequence lead to important structural changes in secondary and tertiary structure that might be the key of different kinetic activities towards a broad range of substrates. All recombinant AtSOT18 proteins showed low substrate specificity with an indolic Gl, while the specificity for aliphatic substrates varied. There is no correlation in the kinetic behavior with the major ds-Gl contents or with the ratio of C-3/C-4 ds-Gl in the respective ecotype. Therefore, is it unlikely that ds-Gl AtSOT18 proteins play a major role in shaping the Gl profile in Arabidopsis
Processi molecolari coinvolti nell'attività anti-biofilm: approccio proteomico multi-strategico
No full textLo sviluppo e la funzionalità di un nuovo materiale antibiofilm non può prescindere dalla comprensione dei meccanismi molecolari che permettono alle molecole che lo compongono di impedire la formazione di un biofilm microbico. Il problema è stato affrontato applicando diversi approcci proteomici. In uno di questi, si è partiti dal presupposto che tali molecole esercitino un'interferenza con la formazione del biofilm mediante l'alterazione di specifici processi molecolari e cellulari del microorganismo sotto bersaglio. Un altro approccio invece nasce dalla condiderazione che un dato composto antibiofilm funzioni interagendo con un bersaglio costituito da una o più proteine specifiche del microorganismo che sono coinvolte in una delle fasi della formazione del biofilm o nel suo mantenimento
Come funzionano i composti antibiofilm?
No full textLo sviluppo e la funzionalità di un nuovo materiale antibiofilm non può prescindere dalla comprensione dei meccanismi molecolari che permettono alle molecole che lo compongono di impedire la formazione di un biofilm microbico. Il problema è stato affrontato applicando diversi approcci proteomici. In uno di questi, si è partiti dal presupposto che tali molecole esercitino un'interferenza con la formazione del biofilm mediante l'alterazione di specifici processi molecolari e cellulari del microorganismo sotto bersaglio. Un altro approccio invece nasce dalla condiderazione che un dato composto antibiofilm funzioni interagendo con un bersaglio costituito da una o più proteine specifiche del microorganismo che sono coinvolte in una delle fasi della formazione del biofilm o nel suo mantenimento
Recombinant expression of a maize ribosome-inactivating protein (B32.66) in Saccharomyces cerevisiae and Escherichia coli
No full textHepatic fibrosis is a result of an imbalance between enhanced matrix synthesis and diminished breakdown of connective tissue proteins, the net result of which is increased deposition of Extra Cellular Matrix. In this concept Matrix Metalloproteinases play an important role because their activity is largely responsible for extra cellular matrix breakdown. In the present study we have tested the influence of curcumin, the active principle of turmeric, on matrix metalloproteinase expression during alcohol and thermally oxidised sunflower oil induced liver toxicity. Male albino Wistar rats were used for the study. The matrix metalloproteinase expressions were found to be increased significantly in alcohol as well as thermally oxidised sunflower oil groups and on treatment with curcumin there was a significant decrease. In alcohol + thermally oxidised sunflower oil group, we found a significant decrease in matrix metalloproteinase activities. Administration of curcumin significantly improved their activities. From the results obtained, we could conclude that curcumin influences the hepatic matrix metalloproteinases and effectively protects liver against alcohol and delta PUFA induced toxicity
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