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A Jacquier

Publications and source records attributed to A Jacquier.

At least 55 records · Page 3Linked to original sources
PubMed1985

An intron-encoded protein is active in a gene conversion process that spreads an intron into a mitochondrial gene.

The intron of the mitochondrial 21S rRNA gene of Saccharomyces cerevisiae possesses a long internal reading frame (ORF) that is conserved in various yeast species. In crosses between intron-plus and intron-minus variants, this intron determines a specific gene conversion phenomenon, which results in the integration of the intron sequence within all previously intron-minus copies of the gene. We show, from a frameshift mutant within the intron ORF and from the need of mitochondrial protein synthesis, that ORF encodes a protein active in the gene conversion that spreads the intron within populations of interbreeding strains. This new intron function is reminiscent of the "transposase" encoded by mobile genetic elements and is discussed in relation to other intron functions.

Base Sequence↗
PubMed1985

Biochemical identification and phylogenetic relationships in free-living amoebas of the genus Naegleria.

Using isoelectric focusing, the zymograms of 23 pathogenic and nonpathogenic Naegleria strains were studied for the activity of 16 enzymes. Certain enzymes (lactate dehydrogenase, L-threonine dehydrogenase, superoxide dismutase, acid phosphatase, malic enzyme, and leucine aminopeptidase) proved particularly useful from a practical point of view as they allow easy and reliable identification of pathogenic N. fowleri and N. australiensis as well as nonpathogenic N. lovaniensis strains. Genetic interpretation of these zymograms gave estimates of genetic distances that largely confirmed the taxonomic position of the Naegleria species. In addition, the genetic data suggest that there are two main phylogenetic groups in the genus Naegleria.

Amoeba↗
PubMed1984

Complexes of serum gamma-glutamyltransferase with apolipoproteins and immunoglobulin A.

We have detected complexes between gamma-glutamyltransferase and apolipoproteins or immunoglobulin A in sera from patients with hepatobiliary diseases but not in sera from healthy individuals. An average of 52.4% of the enzymic activity was precipitated by antiserum against apolipoprotein A, 29.9% by antiserum against apolipoprotein B, and 9.7% by antiserum against immunoglobulin A. Fifty to 60% of the enzyme activity was inhibited in the immunoprecipitates from the transferase fraction bound to apolipoprotein A or immunoglobulin A, and 21% in the fraction bound to apolipoprotein B. We identified the complexed transferase fractions by electrophoresis.

Aged↗
PubMed1984

Associations between serum gamma-glutamyltransferase and apolipoproteins: relationships with hepatobiliary diseases.

We studied the association between gamma-glutamyltransferase (GGT) and apolipoproteins A or B in serum of 42 patients with various hepatobiliary diseases. Binding of the enzyme to apolipoprotein A is not related to a clearly defined disease, but appears to be mainly influenced by the ratio of total cholesterol to GGT activity. An important fraction of GGT activity is associated with apolipoprotein B in patients with icteric or anicteric cholestasis. Conversely, in noncholestatic patients, the percentage of apolipoprotein B-bound GGT activity is low. Addition of the "heavy" form of GGT, obtained by solubilizing the membrane-bound enzyme with detergents, to a serum with low GGT activity led to the binding of the enzyme only to apolipoprotein A. The "light" form of GGT, obtained by limited proteolysis of the "heavy" form and added to the same serum, did not bind to either apolipoprotein A or apolipoprotein B. Thus, the association between the serum enzyme and apolipoprotein A apparently results from nonspecific aggregation of the amphiphilic "heavy" form of the enzyme. The origin of the apolipoprotein B-GGT complexes found in cholestatic patients needs further investigation.

Adult↗
PubMed1983

The intron of the mitochondrial 21S rRNA gene: distribution in different yeast species and sequence comparison between Kluyveromyces thermotolerans and Saccharomyces cerevisiae.

We have screened numerous different yeast species for the presence of sequences homologous to the intron of the mitochondrial 21S rRNA gene of Saccharomyces cerevisiae (intron r1) and found them in all Kluyveromyces species, some of the Saccharomyces species and none of the other yeasts tested. We have determined the nucleotide sequence of the r1-intron in K. thermotolerans and compared it with that of S. cerevisiae. The two introns are inserted at the same position within the 21S rRNA gene. They contain homologous internal open reading frames (ORFs) initiated at the same AUG codon which can be aligned over their entire length. Several silent multi-substitutions indicate that these intronic ORFs represent selectively conserved functional genes. Other intron segments, on the contrary, reveal short blocks of extensive homology separated by non-homologous stretches and/or additions-deletions. Comparison of our two yeast r1-introns with equivalent introns of N. crassa and A. nidulans mitochondria reveals that introns with very similar RNA secondary structures can accommodate different types of ORFs.

Base Sequence↗
PubMed1982

[Contribution of per- and trans-endoscopic pH measurements to the exploration of the upper digestive tract (author's transl)].

Per- and trans-endoscopic pH measurements in the upper digestive tract have provided new and interesting data. Performed by the authors on a series of 314 patients, they showed that the gastric pH is seldom acid, even in duodenal ulcer, and is always alkaline in gastric ulcer and gastric carcinoma. Gastritis may be divided into two groups, depending on whether the pH is normal or hypoacid (4.5 in the antrum, 2.5 in the fundus). Biopsies demonstrated the presence of intestinal metaplasia and epithelial dysplasia in 57.8% of 83 patients with hypoacid gastritis. The method therefore constitutes a simple and reliable means of determining markers of precancerous lesions.

Esophagoscopy↗
PubMed1982

Comparison of fungal mitochondrial introns reveals extensive homologies in RNA secondary structure.

The complete sequences of nine Saccharomyces cerevisiae mitochondrial introns, six of which carry long open reading frames, have already been published. We have recently determined the sequence of an intron in the large ribosomal mitochondrial RNA of Kluyveromyces thermotolerans (Jacquier et al., in preparation), which we found to be closely related to its S. cerevisiae counterpart. This latter result prompted us to undertake a systematic search for possible homologous elements in the other, available sequences with the help of an original computer program. A previously unsuspected wealth of evolutionarily conserved sequences and secondary structures was thus uncovered. Seven at least of the available sequences may be folded up into elaborate secondary structure models, the cores of which are nearly identical. These models result in bringing together the exon-intron junctions into relatively close spatial proximity and looping out either all or most of the sequences in open reading frame, when present. These results and their possible implications with respect to the mechanism of splicing are discussed in the light of available genetic and biochemical data.

Base Sequence↗
PubMed1980

[Cephalic neural crests and disorders of craniofacial morphogenesis. Neurocristopathies (author's transl)].

To establish the pathogenicity, and attempt to define a classification of craniofacial malformations is a difficult task, both in animals and humans. Mention is often made of the classification developed by Paul Tessier, which according to this author "is neither based on a theory nor on an embryonic definition. It is the by-product of anatomical findings during clinical examination and operative dissections" (31). The authors propose an embryologic classification of facial malformations, based on disorders of embryonic development of cells derived from the neural crests (NC) of cephalic origin, and constituting the craniofacial ectomesenchyme. The importance of the cephalic NC derivatives in craniofacial morphogenesis is stressed, and the principal malformations of the cephalic shelf outlined, as a function of disorders occurring during the formation of the NC; migrations, proliferation, and differentiation of their derivatives. The main objective of this study was to formulate pathogenetic hypotheses, to propose a classification, and to stimulate interest in further studies in the realm of physiological and pathological craniofacial morphogenesis.

Bone Diseases, Developmental↗
PubMed1980

[Peripheral haemodynamic disturbances of the limbs in Raynaud's phenomenon (author's transl)].

Study of 36 cases of Raynaud's phenomenon by Doppler effect (radial artery and digital pulp at rest and during hyperhaemia) showed that measurement of peripheral resistance is an excellent method for differentiating idiopathic Raynaud's disease (index higher than 5) from syndromes to obliterative disease of the digital arteries or scleroderma (index less than 4). Capillaroscopy offers additional information concerning the validity of the distal bed, stasis and sludging phenomena and is a diagnostic aid in early scleroderma.

Adult↗
PubMed1979

[Endocrine polyadenomatosis: progressive neurocristopathy (author's transl)].

Endocrine polyadenomatosis forms but a part of the larger group of neurocristopathy disorders. This term includes those affections due to lesions of cells, tissues, or organs derived from the neural crest. The common origin of the various neuro-endocrine cells within the neural crest suggests that there is a denominator of embryologic pathogenicity for the different polyendocrine affections. Knowledge of these is essential for early diagnosis of the different neuro-endocrine lesions, together with a systematic search for any familial associations.

Acromegaly↗
PubMedDate not supplied

[Cardiac imaging].

Explore the source record for details and available documents.

Cardiomyopathies↗