A systematic and comprehensive protocol for rapid orthodontic extrusion.

Objective: The aim of the present paper is to describe a systematic and detailed protocol for rapid orthodontic extrusion, and to summarize the main results of this protocol in terms of migration of dental, hard and soft tissues, for 10 cases.

Clinical Considerations: The working design was to apply a protocol lasting 4 weeks of active phase with intense forces (greater than 300 g), perform weekly the circumferential supra-crestal fiberotomy procedure associated with root-planning, follow up with a passive stabilization phase of another 4 weeks and evaluate the results.

Conclusions: We believe that despite the partial migration of periodontal tissue, the defined protocol we used is, for simplicity of application, brevity of treatment and results, a viable alternative to the surgical technique of clinical crown lengthening in those cases where it is necessary to have more dental tissue exposed for restorative and prosthetic purposes.

Interdisciplinary planning as a landmark for treatment: Case report with a 2-years follow-up.

Case Report: young adult woman with esthetic complaints regarding her smile and frontal teeth aspect. At first glance, the problem seemed to be only the shape of the lateral upper incisors and a small diastema between the central incisors. The diagnosis shared between the orthodontist and the prosthetist led us to consider some other important aspects, such as the deep bite, the teeth inclination and the lips support.

Exploration of pairing constraints identifies a 9 base-pair core within box C/D snoRNA-rRNA duplexes.

2'-O-ribose methylation of eukaryotic ribosomal RNAs is guided by RNA duplexes consisting of rRNA and box C/D small nucleolar (sno)RNA sequences, the methylated sites invariably mapping five positions apart from the D box. Here we have analyzed the RNA duplex pairing constraints by investigating the features of 415 duplexes from the fungus, plant and animal kingdoms, and the evolution of those duplexes within the 124 sets they group into. The D-box upstream 1st and >or=15th positions consist of Watson-Crick base-pairs, G:U base-pairs and mismatched bases with ratios close to random assortments; these positions display single base differences in >60% of the RNA duplex sets.

Myb genes in ciliates: a common origin with the myb protooncogene?

In animals, the protooncogene myb family is characterized by a DNA-binding domain (so-called MYB domain), which consists of 3 imperfect tandem repeats of a helix-turn-helix motif. Homologous genes have been characterized in plants and also in Dictyostelium discoideum. However, in plants, the myb family is more diverse and displays 2 types of MYB domains: the animal-like 3 repeats (MYB-3R) and the 2 repeats (MYB-2R) domains.

The 62-kb upstream region of Bombyx mori fibroin heavy chain gene is clustered of repetitive elements and candidate matrix association regions.

We sequenced an 80 kb DNA region containing the complete sequence of the silkworm Bombyx mori fibroin gene and its flanking, especially the upstream, regions (-62 kb). About 30% of the 62 kb upstream region is composed of repetitive elements including short interspersed elements Bm1, long interspersed elements L1Bm and mariner-like elements Bmmar1 which are widespread over the silkworm genome. This 62 kb region is also enriched of commonly considered matrix association region (MAR) motifs.

Searching for excystment-regulated genes in Sterkiella histriomuscorum (Ciliophora, Oxytrichidae): a mRNA differential display analysis of gene expression in excysting cells.

In the absence of food, the oxytrichid Sterkiella histriomuscorum transforms like many ciliates into resting cysts. When transferred back into feeding medium, the cyst re-transforms into a vegetative cell. The entry into and exit from the dormant cyst stage are complex developmental processes still poorly investigated at the molecular level.

Silk fibroin: structural implications of a remarkable amino acid sequence.

The amino acid sequence of the heavy chain of Bombyx mori silk fibroin was derived from the gene sequence. The 5,263-residue (391-kDa) polypeptide chain comprises 12 low-complexity "crystalline" domains made up of Gly-X repeats and covering 94% of the sequence; X is Ala in 65%, Ser in 23%, and Tyr in 9% of the repeats. The remainder includes a nonrepetitive 151-residue header sequence, 11 nearly identical copies of a 43-residue spacer sequence, and a 58-residue C-terminal sequence.

Fine organization of Bombyx mori fibroin heavy chain gene.

The complete sequence of the Bombyx mori fibroin gene has been determined by means of combining a shotgun sequencing strategy with physical map-based sequencing procedures. It consists of two exons (67 and 15 750 bp, respectively) and one intron (971 bp). The fibroin coding sequence presents a spectacular organization, with a highly repetitive and G-rich (approximately 45%) core flanked by non-repetitive 5' and 3' ends.

Messenger RNA in dormant cells of Sterkiella histriomuscorum (Oxytrichiade): indentification of putative regulatory gene transcripts.

In the absence of food, the oxytrichid Sterkiella histriomuscorum, like many ciliates, enters into dormancy and transforms into a round and walled encysted cell. When transferred back into a feeding medium, the cyst re-transforms into a vegetative cell in a few hours. This encystment-excystment pathway, which is common to many free-living and parasitic protists, is still poorly understood at the molecular level.

Phylogeny of trichomonads based on partial sequences of large subunit rRNA and on cladistic analysis of morphological data.

Several domains of large subunit rRNA from nine trichomonad species have been sequenced. Molecular phylogenies obtained with parsimony and distance methods demonstrate the trichomonads are a monophyletic group which branches very early in the eukaryotic tree. The topology of the trees is in general agreement with traditional views on evolutionary and systematic relationships of trichomonads.

A 28S rRNA-based phylogeny of the gnathostomes: first steps in the analysis of conflict and congruence with morphologically based cladograms.

Approximately 500 nucleotides of 28S rRNA of 31 species of gnathostomes have been sequenced in order to study the phylogeny of the major fish lineages. In maximum parsimony trees, nodes congruent with those of the morphologically based cladogram were found to be robust (chondrichthyans, neopterygians, euteleosteans), but some expected monophyletic groups were not found to be so (lissamphibians, tetrapods, osteichthyans). Possible causes for these discrepancies are discussed.

A broad molecular phylogeny of ciliates: identification of major evolutionary trends and radiations within the phylum.

The cellular architecture of ciliates is one of the most complex known within eukaryotes. Detailed systematic schemes have thus been constructed through extensive comparative morphological and ultrastructural analysis of the ciliature and of its internal cytoskeletal derivatives (the infraciliature), as well as of the architecture of the oral apparatus. In recent years, a consensus was reached in which the phylum was divided in eight classes as defined by Lynn and Corliss [Lynn, D.

ATP synthase subunit c/III/9 gene sequences as a tool for interkingdom and metaphytes molecular phylogenies.

The 38 sequences of the ATPase c/III/9 gene determined in bacteria, fungi, mammals, and higher plants have been used to construct phylogenetic trees by distance matrix and parsimony methods (checked by bootstrapping); alignments have been performed on the deduced amino-acid sequences and then transferred back to the nucleotide sequences. Three lineages stand out: (1) eubacteria (except cyanobacteria and alpha purple bacteria), (2) chloroplasts, together with cyanobacteria, and (3) mitochondria together with nuclei and alpha purple bacteria. The clear monophyly of the mitochondrial/nuclear lineage, taken all together, strongly suggests that the nuclear copies of the gene now residing in the eukaryotic nucleus originate from a mitochondrial transfer.

[Eukaryogenesis: a model derivated from ribosomal RNA molecular phylogenise].

We have undertaken the construction of a broad molecular phylogeny of protists through the comparison of 28S rRNA molecules. The sequences from several major protistan phyla were aligned and combined with a broad database of metazoans, metaphytes, fungi and bacteria and we have derived dendrograms from both distance matrix and parsimony methods. In agreement with classical systematics, a number of monophyletic groups separated by large evolutionary distances were observed (those of the ciliates, the chlorophytes, etc.

An analysis of the origin of metazoans, using comparisons of partial sequences of the 28S RNA, reveals an early emergence of triploblasts.

In order to study the origin of metazoans, we have compared sequences from the 5' end of the large subunit ribosomal RNA of a number of protists, fungi, plants and metazoans, including all diploblastic phyla (sequences of 10 new species have been determined, including that of the placozoan, Trichoplax adhaerens). These sequences were analyzed using distance matrix, maximum parsimony and maximum likelihood methods, and the validity of the results was ascertained with bootstrapping and species removal or addition. Triploblasts and diploblasts formed two clearly separated monophyletic units; this divergence, which apparently preceded the diversification of diploblastic animals (i.

Origin of the algae.

Eukaryotic algae are traditionally separated into three broad divisions: the rhodophytes, the chromophytes and the chlorophytes. The evolutionary relationships between these groups, their links with other eukaryotes and with other photosynthetic groups, such as euglenophytes and cryptophytes, have been the subject of much debate and speculation. Here we analyse partial sequences of the large (28S) cytoplasmic ribosomal RNA from ten new species of protists belonging to various groups of unicellular algae.

[Preliminary molecular phylogeny of the fishes based on sequence analysis of 28S ribosomal RNA].

"Fish" phylogeny has been studied using partial 28 S ribosomal RNA sequences of 14 species among which 12 are "fish" ranging from lamprey to perciforms. Our results are in good agreement with generally accepted cladograms based on anatomical and paleontological data. Two interesting conclusions emerged: a) Polypterus is the sister-group of all other actinopterygians; b) the divergences of the Clasdistia, Tetrapoda and Chondrichthyes seem to have occurred during a relatively short period of time.

Partial phylogeny of the unicellular eukaryotes based on rapid sequencing of a portion of 28S ribosomal RNA.

Using a rapid rRNA sequencing technique, we have determined the sequence of the 400 nucleotides located at the 5' end of the large subunit rRNA molecule from eight species of unicellular eukaryotes (protists). This region contains a pair of conservative domains well-suited for long-range phylogenetic evaluations among eukaryotes, due both to their substantia, length and to their intrinsic rate of sequence variation during evolution. It also comprises a central more rapidly evolving portion, which allows for a fine tuning of distance evaluation between closely related species.

Molecular evolution of the 5'-terminal domain of large-subunit rRNA from lower eukaryotes. A broad phylogeny covering photosynthetic and non-photosynthetic protists.

This paper summarizes the present status of an analysis of protist phylogeny using rapid partial sequencing of 28S rRNA. Data from 12 protistan phyla are now available and have been used to construct a tentative dendrogram based on a distance matrix method. The tree is robust and has considerable internal consistency.

Mitochondria alterations in Cd2+-treated rats: general regression of inner membrane cristae and electron transport impairment.

Young adult rats absorbed 50 p.p.m.

A STEM approach to the study of the proteinaceous architecture of a ribosome.

We used a high-resolution STEM to attempt to recognize the spatial localization of the macromolecular components of ribosomes isolated from Tetrahymena pyriformis. Images obtained either by the annular dark field detector or by the ratio-contrast mode (Z-contrast) show a ribosome as constituted of rounded dark areas, the number and size of which are compatible with those of the protein molecules recognized by biochemistry. Images of different ribosomes, when similar orientations are observed, exhibit a roughly constant pattern of the dark areas.

Effects of chloramphenicol on the mitochondrial respiratory chain in the wild strain and in a cytoplasmic chloramphenicol-resistant mutant of Tetrahymena pyriformis.

The effects of chloramphenicol (CAP) on mitochondrial respiratory activity in the wild strain (ST) and in a cytoplasmic CAP-resistant mutant (STR1) of Tetrahymena pyriformis were studied by determining oxygen consumption, by spectrophotometry, and by cytochemistry. In the absence of CAP both strains had the same respiration capacity, and the low-temperature spectra of their isolated mitochondria were similar. Furthermore, the mitochondria of both strains showed a positive reaction with diaminobenzidine, denoting a similar cytochrome oxidase activity.

The mitoribosomes of a chloramphenicol-resistant cytoplasmic mutant of Tetrahymnea pyriformis differ from those of the wild strain.

The spontaneous CAP-resistant mutant, STR1, has been isolated from the sensitive St-strain of Tetrahymena pyriformis (Curgy et al., Biologie Cellulaire 37, 51-60, 1980; Perasso et al., Biologie Cellulaire 37, 45-50, 1980).