Gino Corsini

Structure and expression of a laccase gene from the ligninolytic basidiomycete Ceriporiopsis subvermispora

A gene encoding laccase has been isolated from a genomic library of the white-rot basidiomycete Ceriporiopsis subvermispora constructed in Lambda GEM-11. This gene (Cs-lcs1) contains an open reading frame of 2215 bp, encoding a mature protein of 499 amino acids with a 21-residue signal peptide. The protein sequence exhibits between 63 and 68% identity with laccases from other basidiomycetes and shares with all of them 10 conserved histidines and one cysteine involved in the coordination of copper atoms at the active site of the enzyme. The gene possesses 11 introns, with splicing junctions and internal lariat formation sites adhering to the GT-AG and CTRAY rules, respectively. The upstream region of Cs-lcs1 contains a TATA box, two CAAT sites, five putative metal response elements and a ACE1 element. In agreement with the presence of the latter element, transcription of Cs-lcs1 is activated by copper and silver, as shown by Northern blot and reverse transcription followed by DNA amplification analyses. Based on Southern blot analysis, Cs-lcs1 appears to be the only gene encoding laccase in C. subvermispora.

Characterization of three new manganese peroxidase genes from the ligninolytic basidiomycete Ceriporiopsis subvermispora.

Three new genes (Cs-mnp2A, Cs-mnp2B and Cs-mnp3) coding for manganese-dependent peroxidase (MnP) have been identified in the white-rot basidiomycete Ceriporiopsis subvermispora. The mature proteins contain 366 (MnP2A and MnP2B) and 364 (MnP3) amino acids, which are preceded by leader sequences of 21 and 24 amino acids, respectively. Cs-mnp2A and Cs-mnp2B appear to be alleles, since the corresponding protein sequences differ in only five residues. The upstream region of Cs-mnp2B contains a TATA box, AP-1 and AP-2 sites, as well as sites for transcription regulation by metals (two), cAMP (two) and xenobiotics (one). Some of these elements are also found in the regulatory region of Cs-MnP3. Transcription of Cs-mnp2A and Cs-mnp2B, but not that of Cs-mnp3, is activated by manganese.

MAGNETIC PROPERTIES AND ANTIBACTERIAL ACTIVITY OF TETRANUCLEAR COPPER COMPLEXES BRIDGED BY OXO GROUP

A series of three tetranuclear Cu(II) complexes of general formula (Cu4OCl6L4), where L is a Lewis Base ligand has been characterized through magnetic

Draft genome sequence of the Chilean isolate Aeromonas salmonicida strain CBA100

We report the draft genome sequence from Aeromonas salmonicida sp. strain CBA100, which was characterized as an antibiotic-resistant bacterium isolated from infected rainbow trout. The total size of the genome is 4,788,109 bp, with a G + C content of 60.55%. Comparison of its open reading frames shows that the closest homologue to one third of the genes of strain CBA100 are found in A. hydrophila. The strain contains several efflux pumps and putative genes that confer resistance to multiclass antibiotics, including macrolide, β-lactamics, florfenicol and quinolones. The antibiogram profile suggests that efflux pumps are the main mechanism of resistance to non-β-lactamic antibiotics. This is the first genome of a Chilean isolate of A. salmonicida, which should shed light on the design of strain-specific vaccines against this pathogen and reduce the use of antibiotics for preventive treatment in Chilean aquaculture.

Two isomorphous transition metal complexes containing a protonated diaminopurine ligand: diaquabis(2,6-diamino-7H-purin-1-ium-κN9)bis(homophthalato-κO)nickel(II) tetrahydrate and the cobalt(II) analogue

The two isomorphous title compounds, [M(C(5)H(7)N(6))(2)(C(9)H(6)O(4))(2)(H(2)O)(2)]·4H(2)O or M(2+)(Hdap(+))(2)(hpt(2-))(2)(H(2)O)(2)·4H(2)O {where dap is 2,6-diaminopurine, H(2)hpt is homophthalic acid [2-(2-carboxyphenyl)acetic acid] and M is Ni(II) or Co(II)}, consist of neutral M(2+)(Hdap(+))(2)(hpt(2-))(2)(H(2)O)(2) monomers, where the M(II) cation lies on an inversion centre and its MN(2)O(4) octahedral environment is defined by one N atom (from Hdap(+)), two O atoms (from one hpt(2-) dianion and one water molecule) and their inversion images. The structures are unusual in that the Hdap(+) cation occurs in an uncommon protonated state (as 2,6-diamino-7H-purin-1-ium) and both ligands bind in an unprecedented monodentate fashion. The existence of a large number of donors and acceptors for hydrogen bonding, together with π-π interactions, leads to a rather complex three-dimensional structure.

Asociación entre obesidad y cáncer de ovario

Obesity is a risk factor for cancer. Epidemiological evidences associate ovarian cancer with obesity. Epithelial ovarian cancer (EOC) is the most common type of ovarian cancer and accounts for a high rate of mortality. The association between ovarian cancer and obesity could be explained by molecular factors secreted by adipose tissue such as leptin. In EOC, leptin increases cell proliferation and inhibits apoptosis. Additionally, adipose tissue synthesizes endogenous estrogens, which increase cell proliferation of epithelial ovarian cells. Also, obesity associated hyperinsulinism could increase ovarian estrogen secretion.

Isolation and molecular characterization of Thraustochytrium strain isolated from Antarctic Peninsula and its biotechnological potential in the production of fatty acids

Thraustochytrids are unicellular protists belonging to the Labyrinthulomycetes class, which are characterized by the presence of a high lipid content that could replace conventional fatty acids. They show a wide geographic distribution, however their diversity in the Antarctic Region is rather scarce. The analysis based on the complete sequence of 18S rRNA gene showed that strain 34-2 belongs to the species Thraustochytrium kinnei, with 99% identity. The total lipid profile shows a wide range of saturated fatty acids with abundance of palmitic acid (16:0), showing a range of 16.1–19.7%. On the other hand, long-chain polyunsaturated fatty acids, mainly docosahexaenoic acid and eicosapentaenoic acid are present in a range of 24–48% and 6.1–9.3%, respectively. All factors analyzed in cells (biomass, carbon consumption and lipid content) changed with variations of culture temperature (10 °C and 25 °C). The growth in glucose at a temperature of 10 °C presented the most favorable conditions to produce omega-3fatty acid. This research provides the identification and characterization of a Thraustochytrids strain, with a total lipid content that presents potential applications in the production of nutritional supplements and as well biofuels.

X-RAY STUDIES AND ANTIBACTERIAL ACTIVITY IN COPPER AND COBALT COMPLEXES WITH IMIDAZOLE DERIVATIVE LIGANDS

The complexes Diaqua-bis(5-nitroimidazole)-copper(II)-dinitrate (1); Tetrakis(4- phenylimidazole)-copper(II)-dinitrate, ethanol solvate (2); Bis(4phenylimidazole)-bis(acetate)-copper(II) (3); Hexakis(4-phenylimidazole)-cobalt(II)-acetate (4) and Bis(2- phenylimidazole)-bis(acetate)-cobalt(II) (5), have been synthesized. Their structures were determined by X-ray analysis. The antimicrobial activities of these complexes have been screened in vitro against the microorganisms Escherichia coli, Klebsiella pneumoniae, Shigella flexneri, Salmonella typhi, Salmonella enteritidis, Salmonella enterica, Staphylococcus aureus , Listeria monocytogenes. Complexes (1) and (3) showed antimicrobial activity over Gram positive and negative bacteria by a bacteriostatic effect. On the other hand, complexes (4) and (5) showed antibacterial activity with a bacteriolytic effect over Gram positive and negative bacteria. The cytotoxicity of complexes (3) and (4) was tested in vitro. These complexes presented cytotoxic effect to values near the MIC.

MAGNETIC BEHAVIOR AND ANTIBACTERIAL ACTIVITY OF IRON (III) COMPLEXES

ABSTRACT The preparation, magnetic characterization and antimicrobial properties of the complexes [Fe 3 O(CH 3 COO) 6 (CH 3 COOH)(H 2 O)]Cl(MeImid)·(H 2 O) (1) and [Fe 4 O 2 (CH 3 COO) 7 O 2 (BPA) 2 (H 2 O)]· Cl·1.25(CH 3 CH 2 OH)(H 2 O) (2), where MeImid is 2-methyl-imidazolium and BPA is 2,2´-bipyridine, are described.The variable temperature susceptibilities of these complexes were investigated in the temperature range 2-300K. The data have been modeled on the assumption of “butterfly” arranged for (2) and equilateral triangle of ferric ions for (1).The antimicrobial activities of these complexes have been screened in vitro against different bacterial strains. The complexes (1) and (2) display activity over Gram negative bacteria and these compounds not present activity over Gram positive strains. These complexes have bacteriostatic effect over bacterial target. The toxicity analyses of iron complexes showed these have cytotoxicity effect to values around the MIC on human cell.Keyword: iron complexes, magnetism, antibacterial activities.e-mail: aatria@ciq.uchile.cl

Draft Genome Sequence of a Copper-Resistant Marine Bacterium, Pantoea agglomerans Strain LMAE-2, a Bacterial Strain with Potential Use in Bioremediation

ABSTRACT Pantoea agglomerans LMAE-2 was isolated from seabed sediment moderately contaminated with Cu2+. Here, we report its draft genome sequence, which has a size of 4.98 Mb. The presence of cop genes related with copper homeostasis in its genome may explain the resistance and strengthen its potential for use as bioremediation agent.