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Effects of UV irradiation on selected pathogens in peptone water and on stainless steel and chicken meat.

Effects of intensity and processing time of 254 nm UV irradiation on Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium were investigated. Intensities measured at 5.08, 10.1, 15.2, and 20.3 cm from the light source were 1.000, 500, 250, and 150 microW/cm2, respectively. Intensities of 250 or 500 microW/cm2 reduced all suspended pathogen cells in peptone water about 5 log cycles after 2 min and completely inactivated L. monocytogenes and E. coli O157:H7 after 3 min by reductions of 8.39 and 8.64 log cycles, respectively. Intensities of 250 or 500 microW/cm2 also reduced (P < or = 0.05) the tested pathogens inoculated on stainless steel (SS) chips, and E. coli O157:H7 was completely destroyed at 500 microW/cm2 for 3 min. After UV treatment for 3 min at 500 microW/cm2, all selected pathogens on chicken meat with or without skin showed reduction ranges from 0.36 to 1.28 log cycles. Results demonstrated that UV irradiation could effectively decrease pathogens in peptone water and on SS but that it was less effective on chicken meat.

Animals↗

Partial replacement of serum with peptone and lactalbumin hydrolysate for the production of foot-and-mouth disease vaccine in BHK-21 cells.

Two batches of experimental media were prepared with Difco-Peptone and Centron-Peptone in combination with lactalbumin hydrolysate (LAH) in Eagle's salts containing 3 amino acids, vitamins and 1% bovine serum. Both medium batches supported the growth of Razi BHK-21 cells in serial passages and the replication of foot-and-mouth disease (FMD) virus type "A". The infectivity and complement fixing antigen (CFU) titres of the virus were comparable with those in Eagle's medium. The protection indices "C" of the experimental batches of vaccine were highly satisfactory. The experimental media saved up to 90% of serum in comparison with Eagle's medium.

Animals↗

[Changes in the antibacterial activity of nitrofurantoin preparations induced by peptone and hydrolysates].

The determination of the activity of the product nitrofurantoin (10 and 100 mcg) versus 324 strains of Gram-negative bacteria showed that the diameter of the inhibition zones and the MIC values on a medium with a definite composition (7SG) are considerably larger than on the Mueller-Hinton (MH) medium, in the bacto-tryptose (BT) medium. An increase with 8-12 mm phi or with 2-4 binary dilutions changes the interpretation from resistant, on the MH and BT media into sensitive on the 7SG medium. The low results recorded on the conventional media reveal the existence of an antagonism between peptone and nitrofurantoin, similar to that known for sulfamides. The authors believe that the peptone antagonism has hindered the knowledge of the activity of the nitrofurfural derivatives and the correct assessment of the bacteria sensitivity. They also consider questionable the elimination tendency of the small dosage of microtablets of nitrofurantoin (10 mcg) and sulfamide (30 mcg), since their apparent insufficiency might be due less to the inadequate contraction of substances and more to the inadequate testing media. The results plead for the use of the media with definite chemical composition sulfamide and nitrofuran antagonists free and for reconsideration of several methodologic problems: use of the media with definite chemical composition; introduction of an intermediary dosage of maximum 100 mcg/microtablet; reassessment of the sensitivity categories for sulphafurazole and nitrofurantoin.

Culture Media↗

Effect of intraduodenal peptone on the lower esophageal sphincter pressure in the dog.

The role of the duodenum in the regulation of the lower esophageal sphincter pressure (LESP) was investigated in 4 unrestrained dogs equipped with a chronic Komarov type esophagostomy, a cutaneous duodenal fistula, a gastrojejunostomy, and a Y anastomosis between the distal end of the duodenum and the midjejunum. Installation of NaCl solution into the duodenum or into the stomach did not effect LESP during the following 60-min observation period. Peptone instillation into the duodenum or into the stomach produced a sustained elevation LESP. The rise of LESP was significantly greater after duodenal than after gastric instillation. Duodenal peptone did not raise serum gastrin. It is concluded that the duodenum may be an important regulator of LESP in the dog and that this effect is not mediated by circulating gastrin.

Animals↗

Comparison of methylated prostaglandin E2 analogues given orally in the inhibition of gastric responses to pentagastrin and peptone meal in man.

In 32 healthy male volunteers the effects on gastric secretion of three methyl analogues of prostaglandin (PG) E2 have been studied, namel, 15 (R) -15-methyl PGE2 methyl ester, 15 (S) -15-methyl PGE2 methyl ester, and 16, 16-dimethyl PGE2. Secretion was measured for 30 min and a PG analogue at doses ranging from 1.25 to 2.5 mug per kg or a placebo was administered. Gastric secretion was then stimulated either by an intravenous infusion of pentagastrin (2 mug per kg-hr) or by a peptone meal with acid secretion determined by intragastric titration technique. The tests were randomized and double blind. All three methyl PG analogues exhibited a profound and prolonged inhibitory action on gastric acid and pepsin secretion induced by pentagastrin. PG analogues caused almost complete inhibition of gastric acid response to a peptone meal accompanied by a significant reduction in the serum concentration of immunoassayable gastrin. Except with the highest dose of PG (S) -15-methyl PGE2 methyl ester, which caused abdominal discomfort and single episodes of diarrhea in some subjects, no symptoms or untoward biochemical effects were observed. It is concluded that these methylated PG analogues are very potent inhibitors of gastric acid and pepsin secretion stimulated by pentagastrin or a meal and may have clinical potential in the treatment of peptic ulcer.

Administration, Oral↗

Effect of 16, 16-dimethyl prostaglandin E2 methyl ester on gastric secretion induced by pentagastrin and pepton meal in man.

In 14 healthy male volunteers the effect of 16,16-dimethyl PGE2 methyl ester (PG/D) on gastric secretion have been studied. Gastric secretion was stimulated by an intravenous infusion of pentagastrin (2 mug/kg/h) with gastric juice collected by aspiration or by a pepton meal with acid secretion determined by intragastric titration technique. Intragastrical administration of PG(D) resulted in a strong decrease of gastric acid and pepsin secretion in tests with pentagastrin. PG(D) caused almost complete inhibition of gastric acid response to a pepton meal accompanied by a marked decline of pepsin concentration in the gastric juice as well as significant reduction in the serum level of immunoassayable gastrin. No side effects were noted during or in succeeding 24 hours after administration of PG(D).

Adult↗

Gas chromatographic comparison of peptone yeast glucose and gas liquid chromatography growth media for anaerobic bacteria.

The growth media peptone yeast extract glucose broth and gas liquid chromatography broth were compared with respect to their suitability for anaerobic bacteria, using 63 strains belonging to 12 species. After incubation for 24 and 48 h the broth cultures were subjected to viable counts and gas chromatographic analysis of short-chain alcohols and fatty acids in head-space vapours and ether extracts. Head-space analysis was superior to the ether extraction method for detecting the rapidly eluting short-chain alcohols. The gas liquid chromatography medium provided superior growth and contained fewer compounds that interfered with the chromatographic analyses. Whereas incubation in gas liquid chromatography medium for 24 h gave characteristic chromatograms for all but one of the studied species, most species required 48 h of incubation in peptone yeast extract glucose medium. Gas liquid chromatography broth is the preferred substrate for use in gas chromatographic identification of anaerobic bacteria.

Alcohols↗

Comparison of selenite F, Muller-Kauffmann tetrathionate and Rappaport's medium for salmonella isolation from chicken giblets after pre-enrichment in buffered peptone water.

Six hundred and eighty three samples of chicken giblets were examined for salmonellas. Three hundred and forty nine of these were neck and crop specimens and 224 were combined liver and heart samples. Two hundred and ten, in all, contained salmonellas. The technique of examination included pre-enrichment in buffered peptone water at 37 degrees C for 18 h and subculture to three enrichment media: Muller-Kauffmann tetrathionate, selenite F and Rappaport's magnesium chloride malachite green broth. Inocula from buffered peptone water to 10 ml of tetrathionate and selenite were 1 ml in each case. The inoculum from the pre-enrichment medium to 10 ml of Rappaport was 0.005 ml. Tetrathionate and selenite were incubated at 43 degrees C for 48 h. Rappaport's medium was incubated at 37 degrees C for 48 h. Subcultures from all three enrichment broths were made at 24 h and 48 h to brilliant green MacConkey agar. Selective agars were incubated at 37 degrees C for 24 h. The most successful technique for salmonella isolation used Rappaport's medium, which was significantly more efficient than either tetrathionate or selenite. This finding reinforces results obtained using sewage polluted natural water as test material and it is suggested that routine examination of environment samples for salmonellas could be based on Rappaport's medium alone. If S. typhi, S. dublin or subgenus III salmonellas were likely to be present in the sample, the technique described here would require modification.

Animals↗

Recovery of the proteose peptone component 3 from cheese whey in Reppal PES 100/polyethylene glycol aqueous two-phase systems.

Recovery of the proteose peptone component 3 from cheese whey was optimal using a 16% (w/w) Reppal PES 100--24% (w/w) PEG 600 aqueous two-phase system, at pH 7, giving a mass recovery yield of 99% and a purity of 83% for proteose peptone component 3 in the upper phase. Using the above system a partition coefficient of 30.7 and a purification factor of 6.9 were achieved.

Animals↗

The composition, structure and origin of proteose-peptone component 8F of bovine milk.

Proteose-peptone component 8F (or '8-fast') has been prepared from bovine milk. Sedimentation equilibrium analysis, polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate and gel filtration in urea-containing buffers all gave molecular weight values between 3300 and 3900. The N-terminal sequence was found to be Arg-Glu- by dansylation and Edman degradation. Hydrazinolysis released lysine from the C-terminus. A mixture of carboxypeptidases A and B showed that the C-terminal sequence was -Thr-(Arg,Ile,Asn)-Lys. The phosphate content was 3.8 mol/mol and was completely released by a short alkaline hydrolysis indicating linkage to serine. This and all other aspects of the composition were entirely consistent with the identification of this proteosepeptone as residues 1--28 of the beta-casein molecule. This identity was confirmed by a peptide mapping procedure. Thus proteose-peptone component 8F represents the N-terminal fragment when the gamma1-caseins are formed by proteolysis of beta-casein.

Amino Acid Sequence↗

Gentamicin-Containing Peptone-Yeast Extract Medium for Cocultivation of Hartmannella vermiformis ATCC 50256 and Virulent Strains of Legionella pneumophila.

We evaluated the use of peptone-yeast extract (PY) medium, different strains of Hartmannella vermiformis, and gentamicin in a coculture system to improve the discrimination of virulent and avirulent strains of Legionella pneumophila. H. vermiformis ATCC 50256 was unique among four strains of H. vermiformis, in that it multiplied equally well in Medium 1034 and PY medium (Medium 1034 without fetal calf serum, folic acid, hemin, and yeast nucleic acid and with a 50% reduction of peptone). However, both a virulent strain of L. pneumophila and its avirulent derivative strain multiplied in cocultures when PY medium was used. The multiplication of this avirulent strain was greatly reduced by incorporating gentamicin (1 (mu)g/ml) into the cocultivation system. Five virulent-avirulent sets of L. pneumophila strains were then tested for multiplication in cocultures with H. vermiformis ATCC 50256 and the gentamicin-containing PY medium. Only the virulent strains multiplied. The modified cocultivation system can discriminate between virulent and avirulent strains of L. pneumophila.

Journal Article↗

Characteristics of bacterial populations responsible for uptake of amino acids in activated sludge acclimated to peptone.

Amino acids (AAs) are produced from the hydrolysis of proteins, which are the major biodegradable organic compounds in municipal sewage. The characteristics of bacterial populations responsible for the assimilation of thirteen AAs into activated sludge (AS) acclimated to peptone are investigated. The results are as follows. (1) The bacterial populations responsible for the uptake of AAs were partly aggregated in AS flocs. (2) The amounts of the bacterial populations responsible for the uptake of leucine, valine, isoleucine, histidine, threonine, lysine and glycine are limited in AS acclimated to peptone. (3) The bacterial populations responsible for the uptake of phenylalanine, leucine and lysine were different. (4) The amounts of bacterial populations responsible for the uptake of aspartate, arginine, alanine, glutamate and phenylalanine are not limited. (5) The functions of the assimilation of these AAs were induced in many bacterial cells as a result of the BOD determination methods applied to these pure AAs.

Amino Acids↗

Effects of volatile fatty acids on a thermophilic anaerobic hydrogen fermentation process degrading peptone.

Hydrogen fermentation using glucose as a single substrate caused abrupt pH drops and the gradual losses of hydrogen producers, which in turn led to system failure. In this study the use of a proteinaceous substrate, peptone, avoided the abrupt pH drops in the reactive system and allowed for further exploration of volatile fatty acids (VFAs) and pH effects on the hydrogen fermentation process. Our results showed that: (1) during the hydrogen fermentation tests, the abrupt pH drops were avoided thus system stability increased due to the production of ammonia from the peptone fermented, (2) pH control was not necessary and the addition of acetate to the process had little effect on the hydrogen fermentation process, (3) at the extreme pHs the addition of acetate either lengthened the lag phase (pH < or = 6) or slowed the hydrogen production rate (pH > or = 8), and both situations were not desired, and (4) high VFA content in the system sped up the consumption of hydrogen gas. Results of this study suggested that the hydrogen fermentation using the protein-containing substances as substrate was beneficial in maintaining the system pH. As long as the pH was maintained around 6-8, system inhibition due to VFAs accumulation was minimized. Thus, the optimal operation of a hydrogen fermentation process would be achievable via the control of substrate composition at a certain carbohydrate-to-protein ratio.

Bioelectric Energy Sources↗

The growth of L-cells and Vero cells on an autoclavable MEM-peptone medium.

The growth of L-60TM cells (a suspension culture adapted L-cell) on media composed of MEM (minimum essential medium (Eagle)) and bactopeptone autoclaved together or separately under a variety of conditions has veen determined. It has been found that MEM autoclaved with 0.5% bactopeptone at 15 psi for 20 min, cooled and then neutralized with NaHCO3, consistently supported good cell growth of L-60TM and L-929 cells. Similar results were obtained when the MEM and bactopeptone were autoclaved separately. The cells grew initially as a monolayer, subsequently becoming a stationary suspension. Some experiments were carried out with agitated suspension culture of L-60TM cells in the autoclaved MEM-bactopeptone combination with and without added methylcellulose and results were obtained which indicate that large scale suspension culture is possible in this system. Other peptones were also found to support cell growth. The autoclaved MEM-bactopeptone combination also supported the growth of Chang liver and Vero cells. The Chang liver cells rapidly dissociated from the plastic surface but the Vero cells remained sufficiently securely attached so that it was possible to grow them near to confluency in roller bottles.

Animals↗

Effect of histamine H2-receptor stimulation on bombesin- and peptone-stimulated gastrin release in man.

This study was undertaken to determine whether histamine H2-receptors are involved in the regulation of gastrin secretion in man. Since previous studies on the effect of histamine H2-receptor blockade on gastrin release are conflicting, we have studied the effect of histamine infusion (130 nmol/kg/hr) with simultaneous H1-receptor blockade on gastrin release in healthy male subjects. Intragastric pH was maintained at 4.5 by continuous intragastric titration during all studies. Histamine did not affect gastrin release stimulated by infusion of bombesin (90 pmol/kg/hr) or by a peptone meal. Integrated gastrin secretion during bombesin plus histamine was 767 +/- 151 pmol X min/liter (+/- SEM), compared to 757 +/- 144 pmol X min/liter during bombesin plus saline (not significant), whereas integrated meal-stimulated gastrin release was 1666 +/- 456 pmol X min/liter during histamine and 1856 +/- 492 pmol X min/liter during saline. It is concluded that histamine H2-receptors do not seem to be involved in the regulation of gastrin secretion in man.

Adult↗

Metabolic roles of peptone and yeast extract for the culture of a recombinant strain of Escherichia coli.

The influence of complex compounds on the growth of a recombinant strain of Escherichia coli containing the gene encoding glyceraldehyde 3-phosphate dehydrogenase, as well as the production of this enzyme have been studied. Batchwise cultures led to an accumulation of acetate, which was not utilized in a yeast extract-free medium. After glucose exhaustion, growth stopped and enzyme activity decreased. Whereas yeast extract allowed acetate assimilation and growth, peptone stabilized the enzymatic activity. The addition of both compounds resulted in optimal performances for enzyme production.

Culture Media↗

Pure pancreatic juice in humans: orange-lemon-juice-induced secretory effects. Comparative analysis with a regular meal, sorbitol, acidified peptone broth and secretin.

The secretory effect elicited by the ingestion of 100 ml of orange-lemon juice (O.-L.J.) was studied on pure pancreatic juice obtained from a catheter placed in the human Wirsung duct at surgery. These changes were compared with those evoked by a regular meal (R.M.), the ingestion of a Sorbitol solution (S.S.), the intragastric infusion of an acidified peptone broth (A.P.B.) and an i.v. single injection of secretin (Boots, 1.0 U/kg). The O.-L.J. induced purer pancreatic secretion response (flow, bicarbonate and enzyme output) than that triggered by the R.M., S.S. and A.P.B. The O.-L.J. evoked peak values, were observed earlier (60 min) than with a R.M. (90 min) ingestion. The 120-min-cumulative values confirmed these findings and disclosed that O.-L.J. elicits a rate of secretion and bicarbonate output closely similar to that of an i.v. secretin injection and amylase response greater than that evoked by this hormone. Thus, O.-L.J. ingestion proved to be an unexpected powerful stimulus of exocrine pancreatic secretion.

Adult↗

New protein hydrolysates from collagen wastes used as peptone for bacterial growth.

A simple and low-cost procedure was developed for the effective processing of native calf skin and blood wastes to produce protein hydrolysates. The method includes extraction of high-molecular-weight protein from the raw material, followed by enzymatic hydrolysis of the extracted residue. The enzymatic hydrolysis was performed by inexpensive commercial subtilisin DY, produced by Bacillus subtilis strain DY possessing high specific activity. The contents of protein, nitrogen, ash, and amino acids of the obtained hydrolysates were determined and compared with those of the commonly used commercial casein hydrolysate (Fluka Biochemica, Switzerland). The newly obtained calf skin hydrolysate, called Eladin, was found to be suitable as a low-cost alternative peptone in growth media of different microorganisms, such as Escherichia coli, Pseudomonas aeruginosa, Salmonella dublin, and Staphylococcus aureus. The method allows utilization of waste materials by converting them into valuable protein products that could find widespread application in microbiologic practice.

Amino Acids↗