Biomedical subjects

Daniel M Lorenzini

Publications and source records attributed to Daniel M Lorenzini.

7 recordsLinked to original sources

PubMed2005

Discovery of immune-related genes expressed in hemocytes of the tarantula spider Acanthoscurria gomesiana.

The present study reports the identification of immune related transcripts from hemocytes of the spider Acanthoscurria gomesiana by high throughput sequencing of expressed sequence tags (ESTs). To generate ESTs from hemocytes, two cDNA libraries were prepared: one by directional cloning (primary) and the other by the normalization of the first (normalized). A total of 7584 clones were sequenced and the identical ESTs were clustered, resulting in 3723 assembled sequences (AS). At least 20% of these sequences are putative novel genes. The automatic functional annotation of AS based on Gene Ontology revealed several abundant transcripts related to the following functional classes: hemocyanin, lectin, and structural constituents of ribosome and cytoskeleton. From this annotation, 73 transcripts possibly involved in immune response were also identified, suggesting the existence of several molecular processes not previously described for spiders, such as: pathogen recognition, coagulation, complement activation, cell adhesion and intracellular signaling pathway for the activation of cellular defenses.

Amino Acid Sequence↗

PubMed2005

GARSA: genomic analysis resources for sequence annotation.

SUMMARY: Growth of genome data and analysis possibilities have brought new levels of difficulty for scientists to understand, integrate and deal with all this ever-increasing information. In this scenario, GARSA has been conceived aiming to facilitate the tasks of integrating, analyzing and presenting genomic information from several bioinformatics tools and genomic databases, in a flexible way. GARSA is a user-friendly web-based system designed to analyze genomic data in the context of a pipeline. EST and GGS data can be analyzed using the system since it accepts (1) chromatograms, (2) download of sequences from GenBank, (3) Fasta files stored locally or (4) a combination of all three. Quality evaluation of chromatograms, vector removing and clusterization are easily performed as part of the pipeline. A number of local and customizable Blast and CDD analyses can be performed as well as Interpro, complemented with phylogeny analyses. GARSA is being used for the analyses of Trypanosoma vivax (GSS and EST), Trypanosoma rangeli (GSS, EST and ORESTES), Bothrops jararaca (EST), Piaractus mesopotamicus (EST) and Lutzomyia longipalpis (EST). AVAILABILITY: The GARSA system is freely available under GPL license (http://www.biowebdb.org/garsa/). For download requests visit http://www.biowebdb.org/garsa/ or contact Dr Alberto Dávila.

Animals↗

PubMed2005

Purification and partial characterization of the plasma clotting protein from the pink shrimp Farfantepenaeus paulensis.

A clotting protein (CP) was purified from the plasma of the pink shrimp Farfantepenaeus paulensis by sequential anion-exchange chromatography. The shrimp CP was able to form stable clots in vitro in the presence of hemocyte lysate and Ca2+, suggesting that the clotting reaction is catalyzed by a Ca2+-dependent transglutaminase present in shrimp hemocytes. Dansylcadaverine was incorporated into the shrimp CP in the presence of endogenous transglutaminase (hemocyte lysate), confirming that the shrimp purified CP is the substrate for the transglutaminase enzyme. The molecular mass of the CP was determined by gel filtration to be 341 kDa and 170 kDa by SDS-PAGE under reducing conditions. These results suggest that the shrimp CP consists of two identical subunits, covalently linked by disulphide bonds. The amino acid sequence at the N-terminus was 100% identical to that of the penaeids Litopenaeus vannamei and Penaeus monodon and 66% to 80% identical to the CPs of other decapods. This is the first report of a CP characterization in an Atlantic penaeid species. Further studies, including a molecular cloning approach would enable to detect which tissues express the gene of the clotting protein. It would be also useful to understand the mechanism by which the coagulation time is delayed in shrimps under stress conditions.

Amino Acid Sequence↗

PubMed2004

Cysteine-rich antimicrobial peptides of the cattle tick Boophilus microplus: isolation, structural characterization and tissue expression profile.

Antimicrobial peptides (AMPs) are components of the immune system of both vertebrate and invertebrate animals. This study describes the isolation, primary structure, cDNA cloning, and tissue expression profile of two cysteine-rich AMPs from the hemolymph of the cattle tick Boophilus microplus. A 10,204 Da polypeptide, with six cysteine residues and no sequence similarity to any known molecule, was isolated from the cell-free hemolymph. Because of its sequence originality, this peptide was named microplusin. The second AMP was isolated from the hemocytes of B. microplus. This peptide, with a molecular mass of 4285 Da and six cysteines, is a defensin with similarity to the insect defensin family members. The cDNA cloning established that microplusin is synthesized as a prepeptide while the tick defensin is synthesized as a prepromolecule. Interestingly, despite the fact that microplusin and defensin have been isolated from different compartments, their gene expression was found to have similar tissue distribution.

Amino Acid Sequence↗

PubMed2003

Acanthoscurrin: a novel glycine-rich antimicrobial peptide constitutively expressed in the hemocytes of the spider Acanthoscurria gomesiana.

We report the isolation of a novel antimicrobial peptide, acanthoscurrin, from the hemocytes of unchallenged tarantula spider Acanthoscurria gomesiana. A combination of Edman degradation, mass spectrometry and cDNA cloning revealed the presence of two isoforms of acanthoscurrin, differing by two glycine residues. Both displayed cationic properties and a high percentage of glycine residues. However, acanthoscurrins have no structural similarities with already known glycine-rich antimicrobial peptides from animals and plants. As deduced from cDNA cloning and mass spectrometry, the amino acid sequence of acanthoscurrin begins with a putative signal peptide of 23 amino acids followed by the mature peptide, which is post-translationally modified by a C-terminal amidation. Acanthoscurrins are constitutively expressed in hemocytes and released to plasma following an immune challenge.

Amino Acid Sequence↗

PubMed2003

Molecular cloning, expression analysis and cellular localization of gomesin, an anti-microbial peptide from hemocytes of the spider Acanthoscurria gomesiana.

Gomesin is a cationic anti-microbial peptide of 18 amino acid residues isolated from the hemocytes of unchallenged tarantula spider Acanthoscurria gomesiana. This paper reports the first study of the processing and cellular location of an anti-microbial peptide (AMP) in spiders. Gomesin cDNA sequence analysis indicated that it is processed from a precursor containing a signal peptide (23 amino acid residues) and a negative C-terminal region (43 amino acid residues). The gomesin gene was constitutively transcribed in hemocytes and the gene product localized in hemocyte granules. The constitutive production of gomesin by a spider is discussed in the context of an ancient mechanism of AMP regulation and storage.

Amino Acid Sequence↗

PubMed2002

Characterization and partial purification of a lectin from the hemolymph of the white shrimp Litopenaeus schmitti.

The agglutinating activity of the hemolymph of Litopenaeus schmitti is insensitive to calcium and specific for acetylated sugars, particularly sialic acid (Neu5Ac) and O-sialoglycoconjugates (bovine submaxillary mucin) and has varying specificity for different LPS, which may suggest a putative role in microorganism recognition. Affinity chromatography on fetuin-agarose of the agglutinin resulted in a 220 kDa band (lectin), and a 82.5 kDa band, which probably is hemocyanin. The 220 kDa protein consists of 31 and 34 kDa subunits, suggesting that this lectin is multimeric. The lectin molecular mass was estimated by gel filtration to be 153+/-10 kDa. The hemolymph of L. schmitti comprises at least another soluble lectin, with distinct chemical and carbohydrate specificity than the 220 kDa lectin.

Animals↗