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C Miceli

Publications and source records attributed to C Miceli.

35 records · Page 2Linked to original sources
PubMed1986

Purification to apparent homogeneity of the mating pheromone of mat-1 homozygous Euplotes raikovi.

Mating type-specific mating pheromones autonomously released into the environment control cell-cell union in conjugation of the marine ciliate Euplotes raikovi. The mating pheromone, termed euplomone r-1, of cells of the homozygous mating type determined by the mat-1/mat-1 genotype was purified by means of a three-stage purification procedure which provides a yield of 79%. Starting from 10 liters of supernatant, 3.3 mg of euplomone r-1 were regularly recovered. Euplomone r-1 was identified with a protein showing a molecular weight of 12,000, an isoelectric point of 3.7, and unusually high contents of cysteine (15%) and tyrosine (5.8%). It appeared active at a concentration of 3.4 +/- 0.5 X 10(-12) M. Carbohydrate and a small colored compound, not yet identified, occurred in association with partially purified euplomone r-1 samples, whereas they were not detected in samples of the final product of purification. An acidic shift was apparently capable of destroying the carbohydrate/euplomone r-1 association, suggesting that it does not involve covalent bonds.

Amino Acids↗
PubMed1986

The ciliate Euplotes raikovi heterozygous at the mat genetic locus coreleases two individual species of mating pheromone: Genetic and biochemical evidence.

Euplotes raikovi of the wild-type strain 13 was found to be heterozygous (mat-1/mat-2) for the genetic locus mat, which is supposed to control the mating-type specificity of freely released mating pheromones ("euplomones"), and capable of yielding the two types of corresponding homozygotes (mat-1/mat-1, mat-2/mat-2). The results of euplomone purification, performed in parallel on Euplotes of the three different genotypes, showed that the heterozygous cells corelease two mat-specific euplomones (namely, euplomone r 1 associated with mat-1 and euplomone r 2 associated with mat-2), while the homozygous cells release either one of the two types according to their genotype. The two euplomones coreleased by the mat heterozygous cells were resolved as separate molecular species present in different relative amounts (euplomone r 1, approximately 70%; euplomone r 2, approximately 30%). A closely similar degree of eccentricity in the euplomone r 1/euplomone r 2 production was again found between the two homozygous cell types. It was concluded that the alleles mat-1 and mat-2 exhibit a relationship of nondominance: the heterozygote apparently behaves as the simple combination of the two corresponding homozygotes. It was inferred that the observed quantitative variations in the production of the different euplomones may be the result of a differential mat gene-type amplification occurring during the development of the cell somatic macronucleus.

Journal Article↗
PubMed1985

Long-term culture and characterization of alloreactive T-cell infiltrates from renal needle biopsies.

Long-term T-cell lines have been established by culturing renal needle biopsies from kidney recipients undergoing graft rejection. These cultures are maintained in the presence of Interleukin 2, with weekly addition of irradiated donor lymphocytes as a source of antigen. The cells express T-cell markers, T3, T4, and T8, T-cell growth factor (IL2) receptor, and HLA-DR antigens. In one cell line, J2, the T4 and T8 antigens are found on two separate cell populations. This line is also shown to specifically kill Epstein Barr Virus transformed donor cells. This cytotoxicity is directed against HLA-B35 determinant and has been maintained in vitro for over 6 months.

Antibodies, Monoclonal↗
PubMed1983

Isolation of the mating-inducing factor of the ciliate Euplotes.

Numerous strains of different mating types of the marine ciliate Euplotes raikovi have been found to be autonomous excreters into the surrounding medium of specific mating-inducing factors (gamones) (Luporini, P et al., J exp zool 226 (1983) 1 [9]). The gamone from the mating type represented by strain 13 has been isolated and identified as a glycoprotein with a molecular weight (MW) of about 12 kD and a pI of 4. It has been termed euplomone r 13. At a concentration of 3 X 10(-12) M, euplomone r 13 specifically induces cells of a complementary mating type to unite in conjugation within 2 h.

Animals↗
PubMed1980

On the role of germ cells in planarian regeneration. II. Cytophotometric analysis of the nuclear Feulgen-DNA content in cells of regenerated somatic tissues.

Previous findings by our group have shown how primordial male germ cells take part in regenerative blastema formation in planarians by migrating to the wound. The role of these cells in rebuilding transected tissues has been investigated in a population of Dugesia lugubris s.l. which is particularly suited for our purpose. In fact, these planarians provide a clear karyological marker to distinguish diploid male germ cells (2n = 8) from tryploid embryonic or somatic cells (3n = 12). In this study we employed the cytophotometric analysis of the nuclear Feulgen-DNA content in order to distinguish non-replicating male germ cells from reserve and somatic cells. The Feulgen-DNA content in cells from the gonad-free caudal area was measured after complete regeneration. Most non-replicating cells (94-95%) were found to have a DNA amount typical of cells previously estimated as triploid. Some (5-6%) nuclei containing a DNA amount typical of cells previously estimated as diploid male gonia were also found. These findings seem to support the view that primordial male germ cells also participate in rebuilding somatic tissues according to the field influence they encounter during regeneration. The possibility that metaplasia (or cell transdifferentiation) may occur in planarians is finally discussed.

Animals↗
PubMed1980

Autoplastic vein grafts in experimental microsurgery.

The writers discuss the histological results of a study of twelve auto-plastic vein grafts performed by a microsurgical technique on the femoral artery of the rabbit. Our observations, which were made at periods of from one to twelve weeks after the grafts had been performed, revealed the details of the nature and chronological development of the structural changes that occurred in the wall of the graft.

Animals↗
PubMed1980

On the role of germ cells in planarian regeneration. I. A karyological investigation.

Specimens from a polyploid biotype of Dugesia lugubris s.l. were used to clarify the role and fate of germ cells during planarian regeneration. These specimens provide a useful karyological marker because embryonic and somatic cells (3n = 12) can be easily distinguished from male (2n = 8) and female (6n = 24) germ cells by their chromosome number. We succeed in demonstrating how primordial germ cells participate in blastema formation and take part in rebuilding somatic tissues. This evidence was obtained by cutting each planarian specimen twice at appropriate levels. The first aimed to induce primordial germ cells to migrate to the wound. The second cut was performed after complete regeneration and aimed to obtain a blastema from a cephalic or caudal area devoid of gonads. A karyological analysis of mitotic cells present in each blastema obtained after the second cut provided evidence that cells, originally belonging to the germ lines, are still present in somatic tissues even months after complete regeneration. The role of primordial germ cells in planarian regeneration was finally discussed in relation to the phenomenon of metaplasia or transdifferentiation.

Animals↗
PubMedDate not supplied

Specific and common epitopes in mating pheromones of Euplotes raikovi revealed by monoclonal antibodies.

Polypeptide mating pheromones Er-1 and Er-2, purified from the supernatant of Euplotes raikovi cultures of mating type I and mating type II, respectively, were used to immunize mice and obtain monoclonal antibodies. Five hybridoma clones producing antibodies specific to the mating pheromones were selected. They were analyzed for immunospecificity by immunoperoxidase assay, immunoblotting, and for their efficacy in inhibition of mating pheromone activity. Monoclonal antibodies from two hybridoma clones recognized only the mating pheromone used as antigen: those from the other three clones reacted, to comparable extents, with both mating pheromones. On the basis of these results it was assumed that two immunogenic sites exist in Er-1 and Er-2, one specific and the other common to both mating pheromones.

Animals↗
PubMedDate not supplied

Identification of the tubulin gene family and sequence determination of one beta-tubulin gene in a cold-poikilotherm protozoan, the antarctic ciliate Euplotes focardii.

Four different tubulin genes were identified in the somatic nucleus (macronucleus) of Euplotes focardii, a strictly cold-adapted, Antarctic ciliate: one of 1,800 bp for alpha-tubulin and three of 2,150, 1,900, and 1,600 bp, respectively, for beta-tubulin. Preliminarily analysed for restriction fragment length polymorphisms, these genes showed remarkable differences in organisation from tubulin genes of other ciliates which live in temperate areas and were analysed in parallel with E. focardii. The complete coding sequence of the 1,600 bp beta-tubulin gene was then determined and shown to contain unique structural features of potential importance for E. focardii microtubule organization and activity. Of eight unique substitutions detected, seven were concentrated in the large amino terminal domain of the molecule that directly interacts with the carboxy terminal region of alpha-tubulin for heterodimer formation. Sequence analysis of the cloned gene revealed, in addition, a potential new exception in the use of the genetic code by ciliates. A TAG codon was aligned in correspondence with Trp-21 which is strictly conserved in every tubulin sequence so far determined.

Amino Acid Sequence↗
PubMedDate not supplied

Chemical signaling in ciliates.

For long, our knowledge of the biology of ciliate pheromones has long relied solely upon the study of the two structurally unrelated "gamones" identified in culture filtrates of a Blepharisma species. However, the characterization of a number of polypeptide pheromones secreted by Euplotes raikovi and E. octocarinatus has now established that structural relationships of homology usually link these molecules, which is consistent with the genetic basis of the mating type systems evolved by these species. In this context, our growing appreciation of the conserved and variable elements of the pheromone architecture should foster progress in the understanding of pheromone-receptor interactions and thus, provide important clues into pheromone mechanisms of action.

Amino Acid Sequence↗
PubMedDate not supplied

Molecular cloning of the gene encoding an acidic ribosomal protein of the P2 family from the ciliate Euplotes raikovi.

We have characterized a macronuclear gene of the ciliate protozoan Euplotes raikovi, which encodes an acidic ribosomal protein of the P protein family. This gene shows the typical organization of the hypotrich ciliate macronuclear "gene-sized" molecules with Euplotes telomeres at the ends. The longest open reading frame encodes a conceptual protein of 113 amino acid residues, with a molecular mass and pI value of 11.45 kDa and 3.97, respectively. By using sequence homology analysis, the protein was found to belong to the ribosomal P2 protein family and was named Er P2, where Er stands for Euplotes raikovi. These proteins, generally called A (acidic/alanine rich) proteins in prokaryotes and P (phosphorylated) proteins in eukaryotes, in which they are divided into P1 and P2 families, play a role in the elongation step of protein synthesis. Approximately 40% amino acid sequence identity was found between the cloned protein and other known protozoan ribosomal P2 proteins. Within its N-terminal half, this protein contains several potential kinase phosphorylation sites. Protein Er P2 differs markedly from the consensus P protein sequence in its C-terminal region, usually highly conserved among eukaryotic ribosomal P proteins, and shows similarities with the C-terminus of the archaebacterial ribosomal A proteins. To our knowledge, this E. raikovi protein represents the first demonstration of a ribosome-associated protein of the P2 family in a ciliate protozoan.

Amino Acid Sequence↗
PubMedDate not supplied

Self from nonself discrimination in single-celled eukaryotes.

A mechanism for self recognition has been proposed to control the mating type interactions in the marine ciliate Euplotes raikovi. The relevant molecules involved in this mechanism are the mating pheromones inherited via high-multiple alleles codominant at the Mendelian locus mat. Four of these mating pheromones have been isolated, purified, and characterized. They are relatively small and acidic proteins (Mr, 11,000-12,000; pI, 3.7-4.0), which are still active at the concentration of approximately 10(-12) molar. Data, yet preliminary, of amino acid sequencing of the purified mating pheromones showed extensive structural homologies and the common presence of the aspartic acid at the amino terminal.

Animals↗
PubMedDate not supplied

Development of the Abbott AxSYM Free PSA assay: performance characteristics and preliminary clinical evaluation.

The AxSYM Free PSA assay was demonstrated to have good analytical sensitivity and reproducibility. The F/T ratio determinations for 385 men tested during the Prostate Awareness Week who had biopsies due to an elevated total PSA value and/or a suspicious DRE demonstrated that the percentage of free PSA was lower in patients found to have prostate cancer than those that were biopsy negative for the overall group and for all patient categories examined. The optimal strategy for combining PSA values, F/T ratios, DRE and other clinical and diagnostic parameters to improve the early detection of prostate cancer requires additional clinical studies.

Humans↗