PubMed Health⌕ Search

Biomedical subjects

F Chartier

Publications and source records attributed to F Chartier.

16 recordsLinked to original sources
PubMed1998

The DNA-binding protein II from Zymomonas mobilis. Complete amino acid sequence and interaction with DNA.

The primary structure of the DNA-binding protein II from Zymomonas mobilis has been determined from data provided by automated Edman degradation of the intact protein and of peptides derived from cleavage at aspartic acid and arginine residues. When compared with the homologous protein isolated from other bacteria, the DNA-binding protein II from Z mobilis shows many substitutions. Several non-conservative substitutions at positions usually highly conserved in this type of protein probably account for the weaker DNA-binding activity of this protein compared to that of the E coli protein.

Amino Acid Sequence↗
PubMed1991

Determination of the DNA-interacting region of the archaebacterial chromosomal protein MC1. Photocrosslinks with 5-bromouracil-substituted DNA.

Protein MC1 is the major chromosomal protein in methanosarcinaceae. Using photochemical crosslinking on 5-bromouracil-substituted DNA, we identified the region of the protein that interacts with it. This region is located in the C-terminal part of the polypeptide chain, and the crosslinked amino-acids are in the region 74-86. Tryptophan 74 is one of the amino-acids crosslinked to DNA.

Archaeal Proteins↗
PubMed1991

[A new case of Mycobacterium bovis pulmonary tuberculosis in the dromedary (Camelus dromedarius) in Mauritania].

A case of pulmonary tuberculosis is described in a dromedary from Nouakchott (Mauritania). Gross lesions affected pulmonary parenchyma, diaphragmatic pleura, pericardium and regional lymph nodes: caseo-calcified nodules, miliary tubercles and haemorrhagic "pendeloques". Microscopically lesions were characterised by granulomatous tissue, epithelioid cells, necrotic material in the centre. No Langhans giant cells were seen. Mycobacterium bovis was isolated from these samples.

Animals↗
PubMed1989

Primary structure of the chromosomal proteins MC1a, MC1b, and MC1c from the archaebacterium Methanothrix soehngenii.

The chromosomal protein MC1 of Methanothrix soehngenii is a family of three variants a, b, and c. These are small basic polypeptides of 89, 87, and 90 residues, respectively. Their primary structures have been determined from automated sequence analyses of the intact proteins and from structural data provided by peptides derived from the variants by cleavage at aspartic acid, glutamic acid, arginine, and methionine residues. By comparison with variant b taken as reference, variants a and c present 18 and 24 differences, respectively. The extent of sequence homologies between protein MC1 from M. soehngenii and proteins MC1 from two other species of Methanosarcinaceae is only 60%. The sequences 17-35 and 45-58 of the protein MC1 appear well conserved. Deletions are observed in region 36-44. Many changes, most of them nonconservative, occur in the carboxyl-terminal third of the protein. However, proline residues at positions 68, 72, 76, and 82 remain strictly conserved. Predictive methods for secondary structures indicate a low content of alpha helix and beta sheet structures in proteins MC1.

Amino Acid Sequence↗
PubMed1989

Primary structure of the chromosomal protein MC1 from the archaebacterium Methanosarcina sp. CHTI 55.

The DNA of the thermophilic archaebacterium Methanosarcina sp. CHTI 55 has been shown to be associated with two proteins called MC1 and MC2, of molecular mass 11 kDa and 17 kDa (Chartier et al. (1988) Biochim. Biophys. Acta 951, 149-156). The most abundant of these proteins, protein MC1, can protect DNA against thermal denaturation. In the present paper we report the covalent structure of protein MC1 and its effect on transcription of DNA in vitro. The covalent structure was determined from automated sequence analysis of the protein and from structural data provided by peptides derived from cleavage of the protein at aspartic acid and arginine residues. The amino-acid sequence of protein MC1 from Methanosarcina sp. CHTI 55 is closely related to that of the protein MC1 (previously called HMb) isolated from Methanosarcina barkeri strain MS: among the nine substitutions observed between the two proteins seven are conservative. Transcription of DNA in vitro is stimulated by protein MC1 at low protein-to-DNA ratio but is inhibited at a ratio higher than 0.1 (w/w), which is the one determined in the bacterial deoxyribonucleoprotein complex.

Amino Acid Sequence↗
PubMed1988

Characterization of the chromosomal protein MC1 from the thermophilic archaebacterium Methanosarcina sp. CHTI 55 and its effect on the thermal stability of DNA.

In the deoxyribonucleoprotein complex of Methanosarcina sp. CHTI 55, DNA is associated with two proteins, named MC1 (methanogen chromosomal protein 1) (Mr 10,760) and MC2 (Mr 17,000). Protein MC1, the most abundant of these proteins, is closely related to the Methanosarcina barkeri MS protein MC1. The effect of Methanosarcina sp. CHTI 55 protein MC1 on the thermal stability of DNA has been studied in native deoxyribonucleoprotein complex, as well as in reconstituted complexes, and it has been compared to the effect of E. coli DNA-binding protein II. Both proteins are able to protect DNA against thermal denaturation, but the differences observed in the melting profiles suggest that they interact by different mechanisms. Moreover, our studies indicate that one molecule of protein MC1 protects eight base pairs of DNA.

Archaea↗
PubMed1986

Primary structure of the chromosomal protein HMb from the archaebacteria Methanosarcina barkeri.

The amino acid sequence of the protein HMb, a protein of 93 residues (Mr 10757) which represents the major acid-soluble component of the Methanosarcina barkeri nucleoprotein complex, has been established from automated sequence analysis of the protein and from structural data provided by peptides derived from cleavage of the protein at aspartic acid, arginine and methionine residues. The protein HMb is mainly characterized by a high amount of charged residues (15% of acidic residues and 26.8% of basic residues) which are distributed all along the polypeptide chain. The amino acid sequence of the protein HMb is not homologous to any eubacterial, archaebacterial or eukaryotic chromosomal proteins known up to now.

Amino Acid Sequence↗
PubMed1983

Utilization of volatile fatty acids and improvement of fluid therapy for treatment of dehydration in diarrheic calves.

Oral glucose-electrolytes solutions have been first developed for treatment of watery diarrhea in situations where resources are limited. However, oral therapy proved by no means to be a limited or alternative form of treatment and it must be now considered as the treatment of choice for acute diarrhea of practically all etiologies. Furthermore, it must be pointed out that, whatever the additional treatments (antibiotics essentially), oral therapy and suppression of milk feeding have to be effected as soon as possible. Glucose-facilited sodium transport is one of the main processes involved in efficiency of oral formulations. However, recent investigations in our laboratory have shown that acetate (and propionate) brought about a substantial stimulation of sodium and water absorption in the small intestine. This effect was all the more interesting since it was observed throughout the small intestine, in contrast to solutes such as glucose, aminoacids or chloride. Furthermore, acetate affords the possibility of having a more physiological Na/Cl ratio, for correction of acidosis. Besides, acetate may display a delayed alkalinizing effect after metabolization. Propionate also exhibits interesting properties on sodium absorption and as glucogenic substrate after absorption. Field evaluation have demonstrated the efficiency of oral formulations including acetate and propionate (treatment of more than 100 000 diarrheic calves), with generally more than 95% success. Further progress should be expected from improvement in energy supply from oral formulations. The problem is at present the matter of investigations, particularly by utilization of lactose in carefully balanced electrolytes formulations.

Acetates↗
PubMed1981

Effect of acetate or chloride anions on intestinal absorption of water and solutes in the calf.

The influence of acetate, compared with chloride, included in glucose-glycine-sodium formulation was investigated in anesthetized calves, using isolated segments of jejunum or ileum filled with one of the formulations. Maximal absorption of water was observed in the jejunum; this absorption was markedly higher with acetate formulations. The absorption of sodium was highest in the jejunum with the acetate formulation. With the acetate formulation, sodium absorption was still substantial in the ileum, but sodium absorption was maximal with the chloride formulation. Acetate was readily absorbed in the small intestine, particularly in the jejunum, whereas chloride was essentially absorbed in the ileum. With acetate formulations, there was a concomitant secretion of chloride and bicarbonate. These results indicate that acetate favors very efficiently the absorption of water and sodium in the jejunum. In addition, acetate has other interesting properties, such as alkalinizing effects after metabolization.

Acetates↗
PubMed1980

Origin and utilization of volatile fatty acids in the rat.

The arteriovenous differences in the caecum of the rat have been compared for volatile fatty acids (VFA) and for electrolytes. Our results suggest the possibility of an exchange between VFA and chloride at the level of the caecal wall, rather than a net exchange between VFA and bicarbonate; however, the role of bicarbonate or Cl- at the cellular level is still unknown. Acetate uptake by the liver was enhanced when acetate in the afferent plasma was increased in fed as in starved rats, showing that acetyl CoA synthetase was still active during starvation. A release of endogenous acetate was only observed in situations of very active ketogenesis (starvation at the end of pregnancy). In physiological conditions, propionate and butyrate reaching the liver were almost quantitatively removed. However, butyrate was taken up by the liver at a higher rate than propionate after intracecal loads. Propionate was very efficiently utilized as a glucogenic substrate and without noticeable disturbance of lactate metabolism. After administration of acetate loads in starved rats, hepatic ketogenesis increased slightly. There was a marked difference between ketogenesis from butyrate in fed and starved rats. The low ketogenesis from butyrate in the fed rats stressed the important role of metabolic pathways of acetyl-CoA utilization in the control of ketogenesis. In contrast to alanine or lactate, propionate was poorly antiketogenic in the rat.

Acetates↗
PubMed1980

Evidence of different types of acidosis associated with diarrhea in the neonatal calf.

Suckling calves suffering from diarrhea at various ages were examined. Striking differences in the biochemical disturbances were observed in plasma between postnatal (2.3 days old, on average) and older calves (14.7 days old). Severe dehydration and hypovolaemia in the youngest calves was accompanied by a marked acidosis with hyperlactataemia, hyperalaninaemia and a considerable increase of most other amino acids. Simultaneously, there was an increase of plasma potassium and of plasma magnesium. In contrast, in diarrheic calves more than 6 days old, acidosis was also observed with minor changes in plasma amino acids and without hyperlactataemia. There were only minimal changes in the plasma magnesium concentration in the older calves. No evident lipomobilization was observed during the course of the disease.

Acidosis↗