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Biomedical subjects

M Gautier

Publications and source records attributed to M Gautier.

At least 19 recordsLinked to original sources
PubMed2001

Characterization of the caprine stearoyl-CoA desaturase gene and its mRNA showing an unusually long 3'-UTR sequence arising from a single exon.

A 5-kb long transcript encoding the stearoyl-CoA desaturase (SCD) was identified by Northern-blot analysis of poly(A)+ mRNA from caprine lactating mammary gland. Complete sequencing of the SCD cDNA (5123 bp) revealed that the coding region (1080 nt) is followed by an unusually long (3.8 kb) 3'-UTR sequence, deriving from a single exon, in which a polymorphism, due to the deletion of a nucleotide triplet, was detected. The complete structural organization of the relevant gene has been determined. The transcription unit was shown to span a 15-kb region and to consist in six exons varying in size from 131 (3rd exon) to 4047 bp (6th exon), and five introns varying in size from 600 to 3700 bp. Using the fluorescence in situ hybridization technique, the SCD gene was localized to bovine and caprine chromosomes 26q21, and ovine chromosome 22q21.

3' Untranslated Regions↗
PubMed2001

First evidence of lysogeny in Propionibacterium freudenreichii subsp. shermanii.

Dairy propionic acid bacteria, particularly the species Propionibacterium freudenreichii, play a major role in the ripening of Swiss type cheese. Isometric and filamentous bacteriophages infecting P. freudenreichii have previously been isolated from cheese. In order to determine the origin of these bacteriophages, lysogeny of P. freudenreichii was determined by isometric bacteriophage type analysis. The genomic DNA of 76 strains were hybridized with the DNA of nine bacteriophages isolated from Swiss type cheeses, and the DNA of 25 strains exhibited strong hybridization. Three of these strains released bacteriophage particules following UV irradiation (254 nm) or treatment with low concentrations of mitomycin C. A prophage-cured derivative of P. freudenreichii was readily isolated and subsequently relysogenized. Lysogeny was therefore formally demonstrated in P. freudenreichii.

Bacteriophages↗
PubMed2001

Assignment of eight additional genes from human chromosome 11 to bovine chromosomes 15 and 29: refinement of the comparative map.

A comparative mapping approach was applied in order to refine the extent and the distribution of conserved segments between human chromosome 11 (HSA11) and cattle chromosomes 15 and 29 (BTA15 and BTA29 respectively). Eight genes from HSA11 were mapped using a bovine-hamster somatic cell hybrid panel and seven represent new assignments. Adding these assignments to those present in human, mouse and cattle databases, a new conserved segment was identified between the telomeric region of HSA11 and BTA29. This brings to seven the number of conserved segments identified between HSA11 and BTA15 and 29, and our study refines their boundaries to the level of the human cytogenetic band.

Animals↗
PubMed2000

Localization by FISH of the 31 Texas nomenclature type I markers to both Q- and R-banded bovine chromosomes.

A series of 31 marker genes (one per chromosome) were localized precisely to both Q- and R-banded bovine chromosomes by fluorescence in situ hybridization (FISH), as a contribution to the revised chromosome nomenclature of the three major domestic bovidae (cattle, sheep and goat). All marker genes except one (LDHA) are taken from the Texas Nomenclature of the cattle karyotype published in 1996. Homologous probes for each marker gene were obtained by screening a bovine BAC library by PCR with specific primer pairs. After labeling with biotin, each probe preparation was divided into two fractions and hybridized to bovine chromosomes identified either by Q or R banding. Clear signals and good quality band patterns were observed in all cases. Results of the two series of hybridizations are totally concordant both for Q and R band chromosome numbering and precise band localization. This work permits an unambiguous correlation between the Q/G- and R-banded 31 bovine chromosomes, including chromosomes 25, 27 and 29 which remained unresolved in the Texas Nomenclature (1996). Hybridization of the chromosome 29 marker gene to metaphase spreads from a 1;29 Robertsonian translocation bull carrier showed a positive signal on the short arm of this rearranged chromosome, confirming that the numbering of this long-known translocation in cattle is correct when referring to the Texas Nomenclature (1996). Taking into account that cattle, goat and sheep have very similar banded karyotypes, the data presented here will help to establish a definite and complete reference chromosome nomenclature for these species.

Animals↗
PubMed1999

Rapid growth of Salmonella enteritidis in egg white reconstituted from industrial egg white powder.

The aim of this study was to evaluate the consequences of the egg white-drying process on egg white ability to limit Salmonella Enteritidis growth in addition to the elucidation of the factors involved. We observed rapid growth of Salmonella Enteritidis inoculated in egg white reconstituted from industrial powder in comparison with that observed in liquid egg white collected in the laboratory: Salmonella cell counts rose from 10(3) to 10(8) cells/ml of egg white from powder during 24 h incubation at 30 degrees C. This rapid growth was observed in powder from all egg-breaking factories investigated, and it was comparable to that observed in optimum medium (tryptone soy broth). In view of the mechanism of egg white resistance and the major role played by iron availability and by ovotransferrin, we investigated several hypotheses to explain this rapid growth: iron provided during the drying process and/or denaturation of protein (especially ovotransferrin). The rapid growth observed in egg white reconstituted from powder was in relation to egg white protein denaturation and especially ovotransferrin denaturation during powder pasteurization that enhanced the availability of iron necessary for Salmonella growth. The major role played by ovotransferrin and iron deficiency on Salmonella growth in egg white was illustrated in this study.

Animals↗
PubMed1998

Combinational variation of restriction modification specificities in Lactococcus lactis.

Three genes coding for a type I R-M system related to the class C enzymes have been identified on the chromosome of Lactococcus lactis strain IL1403. In addition, plasmids were found that encode only the HsdS subunit that directs R-M specificity. The presence of these plasmids in IL1403 conferred a new R-M phenotype on the host, indicating that the plasmid-encoded HsdS is able to interact with the chromosomally encoded HsdR and HsdM subunits. Such combinational variation of type I R-M systems may facilitate the evolution of their specificity and thus reinforce bacterial resistance against invasive foreign unmethylated DNA.

Amino Acid Sequence↗
PubMed1997

Lactobacillus helveticus: strain typing and genome size estimation by pulsed field gel electrophoresis.

Genomic DNAs of 22 strains of Lactobacillus helveticus of various geographical origins were analyzed by pulsed-field gel electrophoresis. Two endonucleases, SmaI and SgrAI, of the 19 tested produced DNA fragments useful for strain comparison. With the endonuclease SmaI, a characteristic restriction pattern was identified for 18 of the 22 strains. The percentage of similarity (Dice coefficient) between the profiles varied between 26% and 100%, and clustering was accomplished by using the unweighted pair group method with arithmetic averages (UPGMA). For the strains showing identical profiles,the high genomic similarity was confirmed when the endonuclease SgrAI was used instead of SmaI. From summation of SmaI and SgrAI fragments from three L. helveticus strains(CNRZ 241, CNRZ 303, and CIP 57.15), the genomic length was estimated at ca.1. 85-2.0 Mb.

Bacterial Typing Techniques↗
PubMed1997

Bacillus cereus necrotizing cellulitis mimicking clostridial myonecrosis: case report and review of the literature.

We describe a case of rapidly progressive necrotizing cellulitis in an immunocompromised farmer caused by Bacillus cereus, and review 15 additional cases of serious soft tissue infection due to this organism reported in the English language literature. These cases illustrate the potential for B. cereus to cause fulminant soft tissue disease indistinguishable from that caused by clostridia.

Bacillaceae Infections↗
PubMed1995

Reclassification of "Propionibacterium rubrum" as P. jensenii.

The taxonomic relationship of strains previously designated as "Propionibacterium rubrum" to P. thoenii and P. jensenii was investigated by use of 16S ribosomal RNA sequence comparison, biochemical characteristics and DNA hybridization. A total of 46 strains representing the species P. jensenii and P. thoenii and the former species "P. rubrum" and also including 21 reference strains and 25 strains isolated from dairy sources were studied. The 16S rRNA sequence of strain "P. rubrum" CNRZ 85 (= ATCC 4871) was found to be almost identical to that of the type strain of P. jensenii. DNA hybridization data indicated that "P. rubrum" should belong to the species P. jensenii rather than P. thoenii, as formerly proposed. The "P. rubrum" strains should then be reclassified as a beta-haemolytic biovar of P. jensenii. The genomic species P. jensenii and P. thoenii could be differentiated by biochemical characteristics such as the production of acid from myo-inositol and starch.

DNA, Bacterial↗
PubMed1995

Occurrence of Propionibacterium freudenreichii bacteriophages in swiss cheese.

We isolated bacteriophages active against Propionibacterium freudenreichii from 16 of 32 swiss cheese samples. Bacteriophage concentrations ranged from 14 to 7 x 10(5) PFU/g, depending on the sample and the sensitive strain used for detection. Only a few strains, 8 of the 44 strains of P. freudenreichii in our collection, were sensitive. We observed that multiplication of bacteriophages occurred in the cheese loaf during multiplication of propionibacteria in a warm curing room, but it seems that these bacteriophages have no adverse effect on the development of the propionic flora. We also found that sensitive cells, originating from either the starter or the cheese-making milk, were present at a high level (10(9) CFU/g) in the cheese.

Bacteriophages↗
PubMed1994

Low efficiency of [14C]galactose incorporation by galactosemic skin fibroblasts: relationship with neurological sequelae.

The incorporation of radioactivity from [1-14C]-galactose into TCA-precipitable material was determined in skin fibroblasts derived from 11 galactosemic patients deficient in galactose 1-phosphate uridyl transferase (GALT-). "R" ratios (designated the R phenotype) were defined as the ratio between [14C]galactose incorporation and [3H]leucine incorporation. Results were expressed as a percentage of the controls. In the GALT-strains this ratio varied from strain to strain, presumably depending on the efficiency of the secondary route via the UDP-galactose pyrophosphorylase pathway. In 10 GALT-patients without late serious clinical manifestations, the R phenotype varied from 37 to 57% of the control value. In the 11th patient, the R phenotype was only 20% of the control. Thus, we obtained a significantly lower R phenotype in one patient who was distinguished from the others by having very severe delayed neurological complications, although compliance to galactose-free diet was good. We suggest that, in this patient, the development of the UDP-galactose pyrophosphorylase pathway was not sufficient to ensure the availability of enough galactose for the necessary synthesis of glycoproteins and glycolipids. Thus the R phenotype may be an indicator of the risk of late neurological complications. The determination of the R phenotype of GALT-patients may therefore be valuable. However, further investigations of galactosemic patients with neurological complications are required to confirm this relationship.

Adolescent↗
PubMed1994

Periodic fluctuations in proliferation of SV-40 transformed human skin fibroblast lines with prolonged lifespan.

A human fibroblastic cell line transformed by the SV40-T antigen sequence and continuously cultured for 7 months displayed large periodic variations in cell proliferation. This contrasted with other characteristics of this cell line that remained constant: mosaic cell shape, absence of cell contact inhibition, and predominance of a hypodiploid population. Similar fluctuations in proliferative capacity were also found during the long-term growth of a transformed but nonimmortalized human fibroblastic line prior to senescence, and in the established hamster fibroblastic Nil cell line. This growth pattern suggests a recurrent stimulation of growth in these three transformed cell lines. The proliferation pattern from cultured transformed cells may thus be complex and requires further investigation. These variations presumably influence major cell functions. This observation has important implications for the analysis of data from such cell lines.

Animals↗
PubMed1994

Fructose-induced enhanced mitogenicity of diploid human cells: possible relationship with cell differentiation.

Fructose strongly stimulates the growth of normal diploid human skin fibroblasts (SFs) and induces marked changes in their morphology and lipid accumulation. This mitogenic effect occurs despite very low fructose consumption and depends on the presence of glutamine. The cell kinetics of cultured fructose-fed human skin fibroblasts were different from those fed on glucose: in the presence of fructose a high proliferative index persisted at Day 14 of culture and the duration of the total cell cycle and of the G1 + 1/2 M and S phases was slightly shorter. The mitogenic effect of fructose on SF was largest in the presence of human serum: it was small or undetectable when fibroblasts were cultured in media supplemented with dialyzed human serum, fetal bovine serum, or serum substitutes. This suggests that serum growth factor(s) mediate the mitogenic effect of fructose. Only normal diploid human cells seem to be sensitive to this mitogenic effect of fructose: the long-term growth of normal human liver cells on fructose was slightly better or similar to that on glucose. In contrast, fructose could only support limited growth of hamster fibroblastic Nil cells and of a transformed human fibroblastic line, which grew better with glucose.

Animals↗
PubMed1994

Multiple myeloma in the elderly.

While multiple myeloma is an incurable disease for nearly all patients, current chemotherapy and supportive care can result in significant disease control and improved duration of survival and quality of life. With the average age of patients about 70, most of the high-dose curative strategies exclude the bulk of patients affected by the disease. Recent advances in understanding the biology and pathophysiology of myeloma have led to novel therapies aimed at altering drug resistance, improving duration of the plateau phase, interrupting the cytokine growth stimulation, and improving management of common complications including infections, anemia, and bone lesions. These latter approaches are not restricted to younger patients, and early evidence indicates that elderly patients are also likely to benefit.

Aged↗