Lucio Cariello

Cloning of ascidian homeobox genes provides evidence for a primordial chordate cluster

In order to isolate genes important in controlling embryonic development in Tunicates, a genomic library from the ascidian Ciona intestinalis was screened with a degenerate oligodeoxyribonucleotide encoding the third helix of Antennapedia-type homeoboxes. Fourteen C. intestinalis homeobox genes, corresponding to several classes of homeodomains, have been identified. Five of the isolated homeoboxes show their highest homology to members of the Vertebrate HOX clusters. mRNAs for two of the isolated homeoboxes are present in unfertilized C. intestinalis eggs.

Molecular forms of immunoreactive gonadotropin-releasing hormone in hypothalamus and testis of the frog, Rana esculenta.

The hypothalamus and the testis of the frog, Rana esculenta, contain gonadotropin-releasing hormone (Gn-RH)-like peptides which are recognized by an antiserum raised against mammalian Gn-RH. Two molecular forms which coelute with synthetic chicken II and salmon Gn-RH from reverse-phase HPLC were distinguished in the hypothalamus. A single peak coeluting with synthetic chicken II Gn-RH was present in the testis.

Transglutaminase activity is related to CAG repeat length in patients with Huntington’s disease

Abstract Huntington’s disease (HD) is a neurodegenerative disorder associated with CAG repeat expansion. We measured transglutaminase (TGase) activity in lymphocytes from 35 HD patients and from healthy individuals to ascertain whether it was altered in this condition. TGase activity was above maximum control levels in 25% of HD patients; it was correlated with the age of the patient and inversely correlated with the CAG repeat length. These results suggest that: (1) HD could be biochemically heterogeneous, and (2) the length of the CAG repeat expansion/TGase ratio could be important in the manifestation of HD.

α- and β-cephalotoxin: Two paralysing proteins from posterior salivary glands of Octopus vulgaris

Abstract 1. 1. Cephalotoxin has been extracted from the posterior salivary glands of Octopus vulgaris and has been fractionated in five components, two of which (α- and β-cephalotoxin) were further purified on Sephadex G-200 superfine. Their molecular weight, as determined on Biogel P-150, are equal to 91,200 and 33,900 respectively. 2. 2. Cephalotoxins are glycoproteins which contain approximately 50% of carbohydrates. Their acidic nature is indicated by the isoelectric point and by the amino acid analysis. 3. 3. α- and β-Cephalotoxin from O. vulgaris , which have been compared with the active components isolated from other Cephalopods, have a strong paralysing effect upon crabs. This has been used for the bioassay studies.

Isolation and characterization of two genes encoding calitoxins, neurotoxic peptides from Calliactis parasitica (Cnidaria)

Among sea anemone neurotoxins, calitoxin, recently isolated from Calliactis parasitica, is a highly toxic peptide of 46 amino acids (aa), whose sequence differs greatly from that of all sea anemone toxins isolated so far. In this study, two genes (clx-1 and clx-2) coding for two highly homologous calitoxins were isolated and characterized from a C. parasitica genomic library. The clx-1 gene encodes the already known calitoxin sequence, named CLX-I, whereas a single bp substitution in the coding region of clx-2 is responsible for a single Glu6-->Lys replacement in a new peptide named CLX-II. The structural organization of the two genes is very similar: two introns and three exons, whose sequences are highly homologous for clx-1 and clx-2 (95% identity). The open reading frame (ORF) of both clx-1 and clx-2 codes for a precursor peptide of 79 aa, whose N-terminus has the feature of a single peptide, while the C-terminus corresponds to the sequences of mature CLX-I and CLX-II. The finding that a pair of basic aa is located upstream from the sequence of both mature toxins strongly suggests that proteolytic events, at specific cleavage sites, are responsible for the release of neurotoxins from their respective precursor molecules.

Structure of two biologically active sesquiterpenoid amino-quinones from the marine spongeDysidea avara

The structures of 2 minor constituents of the marine spongeDysidea avara, which induce developmental aberrations in sea-urchin eggs, are described. The structures were confirmed also by a simple synthesis from avarol (1).

Posidonia ecosystem—V. Phenolic compounds from marine phanerogames, Cymodocea Nodosa and Posidonia Oceanica

Abstract 1. 1. A preliminary study of the phenolic compounds in two marine phanerogames, Cymodocea nodosa and Posidonia oceanica , has been undertaken. 2. 2. Several phenols have been isolated and identified by their chemical and physical properties.

A new transglutaminase‐like from the ascidian Ciona intestinalis 1

A cDNA clone encoding a transglutaminase (TGase) was isolated from a cDNA library prepared from the larval stage of Ciona intestinalis. The cDNA sequence has an open reading frame encoding a protein of 696 amino acids and is about 36% identical to 11 other TGase sequences. In addition, the critical residues thought to form the catalytic center are conserved. The Ciona TGase (CiTGase) has an extension of 39 amino acids in the NH2‐terminal region similar to that reported for keratinocyte TGases. A phylogenetic analysis among other types of TGases demonstrated that CiTGase represents a new type of the enzyme.

Partial characterization of suberitine, the neurotoxic protein purified from Suberites domuncula

Abstract 1. 1. The protein (mol. wt 28.000) consists of four subunits, which are not equivalent as regards the chemical composition, although all of them lack free terminal amino groups. 2. 2. The single subunits also possess different conformations since both photosensitized oxidation studies and acrylamide-quenching experiments of the protein fluorescence emission show that the three tryptophyl residues have a different accessibility to the aqueous solvent. 3. 3. Circular dichroism and fluorescence polarization studies suggest that suberitine has a remarkable tight three-dimensional organization: e.g., exposure of suberitine to 6 M urea for several hours is necessary to obtain a general unfolding of the protein molecule.

Natural variation of model mutant phenotypes in Ciona intestinalis.

Background The study of ascidians (Chordata, Tunicata) has made a considerable contribution to our understanding of the origin and evolution of basal chordates. To provide further information to support forward genetics in Ciona intestinalis, we used a combination of natural variation and neutral population genetics as an approach for the systematic identification of new mutations. In addition to the significance of developmental variation for phenotype-driven studies, this approach can encompass important implications in evolutionary and population biology. Methodology/Principal Findings Here, we report a preliminary survey for naturally occurring mutations in three geographically interconnected populations of C. intestinalis. The influence of historical, geographical and environmental factors on the distribution of abnormal phenotypes was assessed by means of 12 microsatellites. We identified 37 possible mutant loci with stereotyped defects in embryonic development that segregate in a way typical of recessive alleles. Local populations were found to differ in genetic organization and frequency distribution of phenotypic classes. Conclusions/Significance Natural genetic polymorphism of C. intestinalis constitutes a valuable source of phenotypes for studying embryonic development in ascidians. Correlating genetic structure and the occurrence of abnormal phenotypes is a crucial focus for understanding the selective forces that shape natural finite populations, and may provide insights of great importance into the evolutionary mechanisms that generate animal diversity.