Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PEPTONES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources
PubMed1963

Bacteriology of Manganese Nodules: I. Bacterial Action on Manganese in Nodule Enrichments.

Bacteria, found in manganese nodules from the Atlantic Ocean, enhance the adsorption of Mn from sea water by crushed manganese nodules in the presence of peptone. When bacterial outgrowth from crushed manganese nodules was experimentally delayed, peptone did not enhance Mn adsorption by nodular substance, but hindered it in some cases. A mechanism to explain the role of bacteria in enhancing Mn adsorption by manganese nodules is presented. Oyster shells were shown to adsorb Mn in the absence of bacteria. Peptone did not enhance the rate of Mn adsorption. Adsorbed Mn was not visibly oxidized during experimental observation. These results suggest one way whereby nodule formation may be initiated in the oceans. Some bacteria in the nodules were found to release manganese from them in the presence of glucose and peptone. Bacteria may, therefore, play a role not only in nodule buildup but also in nodule breakdown.

Journal Article↗
PubMed1983

Extracellular acid proteases produced by Saccharomycopsis lipolytica.

Saccharomycopsis lipolytica CX161-1B produced at least three extracellular acid proteases during exponential growth in medium containing glycerol, Difco Proteose Peptone, and mineral salts at pH 3.4 (Difco Laboratories, Detroit, Mich.). Little extracellular acid protease activity was produced with glutamic acid as the sole nitrogen source, somewhat higher levels were obtained with peptone, and much higher levels were obtained with Difco Proteose Peptone. The relative amounts of the three proteases varied during growth on Difco Proteose Peptone, which suggested that the proteases were not coordinately regulated. The proteases were purified to near homogeneity (as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) by use of ultrafiltration, gel filtration, and DEAE-Sephacel and hydroxylapatite chromatography. Protease I had a molecular weight near 28,000, an isoelectric point of pH 4.9, and a pH optimum of 3.5. Protease II had a molecular weight near 32,000 and a pH optimum of 4.2. Protease III had a molecular weight near 36,000, an isoelectric point of 3.8, and a pH optimum of 3.1. All three proteases were glycoproteins; proteases I, II, and III contained 25, 12, and 1.2% carbohydrate, respectively. The proteases were inhibited by pepstatin and 1,2-epoxy-3-(4-nitrophenoxy) propane and were largely insensitive to diazoacetyl-DL-norleucine methylester and to compounds which inhibit the serine, sulfhydryl, or metallo-proteases.

Ascomycota↗
PubMed1997

Specific adaptation of gastric emptying to diets with differing protein content in the rat: is endogenous cholecystokinin implicated?

BACKGROUND: Recent studies indicate that gastric emptying may be influenced by patterns of previous nutrient intake. Endogenous cholecystokinin (CCK), whose synthesis and release can be affected by dietary intake, has a major role in the regulation of gastric emptying. AIMS: To evaluate the influence of diets with differing protein content on gastric emptying of differing liquid test meals and plasma CCK levels in the rat and to check whether the inhibitory effect of exogenous CCK on gastric emptying is modified after long term intake of diets with differing protein content. METHODS: Rats were fed for three weeks with high protein, medium protein (regular), or low protein diet. On day 22 gastric emptying of a peptone meal was studied. In addition, basal and postprandial CCK levels after the different dietary regimens were measured by bioassay. The time course of dietary adaptation was studied and its specificity assessed through the use of different (peptone, glucose, and methylcellulose) test meals. The effect of exogenous CCK-8 on gastric emptying was studied at the end of the adaptation period (three weeks). RESULTS: Feeding the animals with a high protein diet for three weeks resulted in a significant (p < 0.05) acceleration (by 21.2 (8.2)%) of gastric emptying while feeding with a low protein diet was followed by a significant (p < 0.05) delay (by 24.0 (6.2)%) in the emptying rate. When the time course of the effect of dietary adaptation on gastric emptying was studied, it appeared that at least two weeks are required for dietary protein to be effective. The regulatory effect of dietary protein on gastric emptying proved to be dependent on meal composition. Only the emptying rate of a protein containing meal (40% peptone) was significantly modified by previous dietary intake. No significant (p > 0.05) changes were observed with glucose and methylcellulose meals whose emptying rates were similar in rats receiving a high protein or low protein diet. A peptone meal strongly and significantly (p < 0.05) increased plasma CCK levels in rats fed a medium protein (regular) diet. Results were similar in rats receiving a low protein diet (p < 0.05) but not in rats on a high protein diet (p > 0.05). As a consequence, postprandial plasma levels of CCK in rats fed with a medium or low protein diet were significantly (p < 0.05) higher than those in rats receiving a high protein diet. In rats on high and low protein diets, dose response curves to CCK-8 were virtually identical, suggesting that dietary protein intake has no influence on the effect of exogenous CCK. CONCLUSIONS: These results clearly show that gastric emptying of a protein containing meal can be modified by previous dietary protein intake. This effect, which is time dependent and meal specific, may be related to changes in endogenous CCK release which will affect emptying rate. While the exact mechanisms underlying this adaptive response need to be studied and clarified further, these results emphasise the importance of dietary history in the evaluation and interpretation of gastric emptying data.

Adaptation, Physiological↗
PubMed1963

Comparison of colicine production and diffusion on different solid media.

Using a freezing-thawing method for extracting colicine from solid media it has been shown that the choice of media for production and diffusion is important. Digest nutrient agar yielded the most colicine and peptone water agar the least. A factor in bacteriological peptone, but absent in a proteose peptone (Difco) and Neopeptone, was responsible for inhibiting production on peptone water agar. Dextrose reduced the diffusion of colicine. A minimum of six hours' incubation of the colicinogenic organism was required for satisfactory production of colicine.

Journal Article↗
PubMed1990

Luminal CCK-releasing factors in the isolated vascularly perfused rat duodenojejunum.

The factors operating at the apical side of the endocrine cell releasing cholecystokinin (CCK) were investigated using the isolated vascularly perfused rat duodenojejunum. In the protease-free intestinal segment, a 30-min infusion of glucose (280 mM), oleic acid (100 mM), or triglycerides containing short- or long-chain fatty acids did not alter significantly the basal level of portal CCK-like immunoreactivity (CCK-LI), while octanoic acid (100 mM) produced a transient rise of plasma CCK-LI to approximately 250% of basal. Infusion of proteins (5% solutions of ovalbumin or casein) or of a mixture of all amino acids brought about a modest CCK secretion. In contrast, isocaloric amounts of an ovalbumin hydrolysate produced a sharp rise of portal CCK-LI to 530% of basal followed by a well-sustained plateau secretion (420% of basal) until the end of the infusion. An acid casein hydrolysate induced a slightly less pronounced CCK-LI release and was followed in decreasing order by meat, casein, and soybean peptones. Simultaneous infusion of trypsin with ovalbumin or casein hydrolysate reduced by approximately 60% the CCK release induced by peptone alone. This effect was reversed by coinfusion of soybean trypsin inhibitor (SBTI) with the trypsin-peptone mixture. Arterial infusion of tetrodotoxin (10(-6) M) or atropine (10(-5) M) had no significant effect on the trypsin-induced inhibition of peptone-mediated CCK-LI release. Administration of SBTI or camostate alone or in combination with trypsin did not alter basal CCK. Monitor peptide produced a dose-dependent transient rise of portal CCK-LI over the range from 2 to 12 micrograms.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1993

CD18-independent neutrophil and mononuclear leukocyte emigration into the peritoneum of rabbits.

The CD18 mAb 60.3 and the CD49d mAb HP1/2 were given at the time of intraperitoneal instillation of either protease peptone or live Escherichia coli bacteria and at 12 h. Leukocyte emigration was evaluated at 4 and 24 h. PMN emigration 4 h after protease peptone instillation and injection of both mAbs was 10% of that in saline treatment. It was 15% of that in saline treatment after mAb 60.3 alone and unchanged by mAb HP1/2. At 24 h PMN emigration in response to protease peptone was not prevented by either CD18 or CD49d mAbs, however, when given together emigration was 10% of saline-treated animals. Mononuclear cell emigration to protease peptone was enhanced at 4 h by both CD18 and CD49d mAbs. The CD18 mAb did not augment mononuclear emigration in response to live bacteria. At 24 h, neither the CD18 nor the CD49d mAb alone blocked emigration of mononuclear cells, but the combination of the two did. These studies demonstrate that: (a) early (4 h) PMN emigration is CD11/CD18 dependent; (b) late (24 h) PMN emigration is CD11/CD18 independent; and (c) mononuclear cells utilize the integrins CD18 and CD49d.

Animals↗
PubMed1991

Methods for inoculation and recovery of Salmonella from chicken eggs.

Various methods of applying inoculum and recovering low numbers of artificially inoculated Salmonella typhimurium on eggs were evaluated. Inoculation methods tested were suspending cells in 1) .85% saline; 2) 1% peptone; 3) sterile chicken fecal paste; or 4) a 1:10 dilution of chicken feces in .85% saline. Sampling methods tested were 1) shell and membrane massage; and 2) mortar and pestle grinding of shells and membranes. The method that yielded the best recovery of low numbers of Salmonella was as follows: 1) apply cell suspension in 1% peptone to egg; 2) sample egg by a hand crush and massage of shell and membranes in 50 mL of buffered peptone; 3) incubate shell and membranes in buffered peptone overnight and then plate onto selective agar. Methods that did not improve sensitivity of recovery included varying the inoculum drying time, addition of FeSO4 or Cleland's reagent to the recovery medium, and varying the temperature of the inoculum to affect penetration.

Animals↗
PubMed2004

Diffusion of lactate and ammonium in relation to growth of Geotrichum candidum at the surface of solid media.

Geotrichum candidum was cultivated at the surface of solid model media containing peptone to simulate the composition of Camembert cheese. The surface growth of G. candidum induced the diffusion of substrates from the core to the rind and the diffusion of produced metabolites from the rind to the core. In the range of pH measured during G. candidum growth, constant diffusion coefficients were found for lactate and ammonium, 0.4 and 0.8 cm(2) day(-1), respectively, determined in sterile culture medium. Growth kinetics are described using the Verlhust model and both lactate consumption and ammonium production are considered as partially linked to growth. The experimental diffusion gradients of lactate and ammonium recorded during G. candidum growth have been fitted. The diffusion/reaction model was found to match with experimental data until the end of growth, except with regard to ammonium concentration gradients in the presence of lactate in the medium. Indeed, G. candidum preferentially assimilated peptone over lactate as a carbon source, resulting in an almost cessation of ammonium release before the end of growth. On peptone, it was found that the proton transfer did not account for the ammonium concentration gradients. Indeed, amino acids, being positively charged, are involved in the proton transfer at the beginning of growth. This effect can be neglected in the presence of lactate within the medium, and the sum of both lactate consumption and ammonium release gradients corresponded well to the proton transfer gradients, confirming that both components are responsible for the pH increase observed during the ripening of soft Camembert cheese.

Cheese↗
PubMed1995

Enhancement of peritoneal macrophages reduces postoperative peritoneal adhesion formation.

Postoperative adhesion formation results from a fibroproliferative inflammatory reaction. Macrophages are critical in the final resolution of the inflammatory process and tissue repair, including modulation of proliferation and differentiation of fibroblasts and secretion of neutral proteases like plasminogen activator. We, therefore, studied the influence of peritoneal macrophage enhancement on postoperative adhesion formation in five groups of rabbits. Group 1 was a control with normal peritoneum. Animals in group 2 had increased macrophage population in their peritoneum by intraperitoneal injection of protease peptone 3 days before adhesion induction. In group 3, animals were treated by protease peptone as in group 2 and then depleted of the increased macrophage population by peritoneal lavage before adhesion induction. In group 4 macrophages were transplanted from animals enriched as in group 2 into a nonenriched peritoneum at the time of adhesion induction. Group 5 had a normal peritoneum with peritoneal lavage before adhesion induction. Peritoneal adhesions were induced at laparotomy by repairing a peritoneal defect in two different models. It was found that enhancement of peritoneal macrophages by protease peptone reduced markedly the degree of postoperative adhesion formation. After depletion of the enhanced peritoneal macrophages by peritoneal lavage the degree of adhesion formation was equivalent to that of controls. Finally, macrophage transplantation into a nonenhanced macrophage peritoneum also reduced the degree of postoperative adhesion formation. It is concluded that enhancement of peritoneal macrophages reduces postoperative peritoneal adhesion formation.

Animals↗
PubMed1993

Intestinal fat digestion plays a significant role in fat-induced suppression of gastric acid secretion and gastrin release in the rat.

We have investigated the role of intestinal fat digestion in fat-induced suppression of gastric acid secretion and gastrin release in the rat. Intraduodenal administration of oleic acid (10%, pH 6.5) and triglyceride (10%, pH 6.5) at a rate of 2 ml/hr resulted in significant suppression of gastric acid secretion and gastrin release stimulated by intragastric perfusion of peptone (0.5%). Diversion of pancreatic juice from the duodenum completely abolished triglyceride-induced inhibition of peptone-stimulated gastric acid secretion and plasma gastrin release, but oleic acid-suppressed gastric acid secretion and gastrin release were unaffected by pancreatic juice diversion. Intraduodenal administration of digested triglyceride, prepared by preincubation with lipase, caused significant suppression of the peptone-induced gastric acid secretion and rise in plasma gastrin levels, even though pancreatic juice was excluded. The results of this study indicate that digestive products of triglyceride by pancreatic juice, especially by lipase, are responsible for the intestinal fat-induced inhibition of gastric acid secretion and gastrin release and that intestinal fat digestion plays a significant role in the mechanism.

Animals↗
PubMed1989

Effect of medium on the bacteriocin production by Klebsiella pneumoniae.

The influence of growth media and media constituents on bacteriocin production by Klebsiella pneumoniae was studied. Among the standard laboratory media used trypticase soy broth (TSB) showed the maximum production and poor yields resulted from growth in peptone water and nutrient broth. A number of peptones differed in their bacteriocin production. Best yields were observed in tryptone and proteose peptone water. Addition of 1% yeast extract to TSB further stimulated bacteriocin production. However, activity was low when glucose, glycine, sodium mercaptoacetate or bile salt mixture were added to the medium. Suppression of synthesis by certain agents as well as inhibition of formed bacteriocin by the others appears to affect the bacteriocin yield. No proteinase activity was detected during the entire incubation period.

Bacteriocins↗
PubMed2006

Sugarcane molasses and yeast powder used in the Fructooligosaccharides production by Aspergillus japonicus-FCL 119T and Aspergillus niger ATCC 20611.

Different concentrations of sucrose (3-25% w/v) and peptone (2-5% w/v) were studied in the formulation of media during the cultivation of Aspergillus japonicus-FCL 119T and Aspergillus niger ATCC 20611. Moreover, cane molasses (3.5-17.5% w/v total sugar) and yeast powder (1.5-5% w/v) were used as alternative nutrients for both strains' cultivation. These media were formulated for analysis of cellular growth, beta-Fructosyltransferase and Fructooligosaccharides (FOS) production. Transfructosylating activity (U ( t )) and FOS production were analyzed by HPLC. The highest enzyme production by both the strains was 3% (w/v) sucrose and 3% (w/v) peptone, or 3.5% (w/v) total sugars present in cane molasses and 1.5% (w/v) yeast powder. Cane molasses and yeast powder were as good as sucrose and peptone in the enzyme and FOS (around 60% w/w) production by studied strains.

Aspergillus↗
PubMed2006

Optimization of an ethanol production medium in very high gravity fermentation.

Concentrations of Mg(2+), glycine, yeast extract, biotin, acetaldehyde and peptone were optimized by a uniform design process for ethanol production by Saccharomyces cerevisiae. Using non-linear step-wise regression analysis, a predictive mathematical model was established. Concentrations of Mg(2+) and peptone were identified as the critical factors: 50 mM Mg(2+) and 1.5% (w/v) peptone in the medium increased the final ethanol titre from 14.2% (v/v) to 17% (v/v) in 48 h.

Acetaldehyde↗
PubMed1981

Bombesin stimulates human gastric function by gastrin-dependent and independent mechanisms.

Studies were performed in six men to determine the relationship between serum gastrin concentration and gastric function during exogenous and endogenous stimulation of gastrin release. When the intragastric pH was maintained at 5.0, there were dose-related increases in gastric acid secretion with increasing serum gastrin concentrations produced either by stepwise increasing doses of intravenous gastrin or bombesin, or by intragastric perfusion with peptone. When intragastric pH was maintained at 2.5, or when intravenous atropine was given hourly, sensitivity to both exogenous and endogenously released gastrin were similarly decreased. Gastric emptying was inhibited in a dose-dependent manner by both bombesin and peptone but not by exogenous gastrin. These results suggest that bombesin and peptone stimulate gastric acid secretion through release of circulating gastrin but inhibit gastric emptying by another mechanism.

Adult↗
PubMed2000

Stressed salmonella are exposed to reactive oxygen species from two independent sources during recovery in conventional culture media.

Previously, Stephens et al. [J. Appl. Microbiol. 83 (1997) 445-455] developed a sensitive technique for studying the resuscitation of low levels of stressed Salmonella. Using this technique the influence on recovery performance of the peptone component of buffered peptone water was investigated. Within 12 different peptone types as much as 3.5 log10 cells/ml difference was observed between the best and worst performing formulations. Poor recovery performance was linked to reactive oxygen species (ROS) generation through auto-oxidation of reducing sugars and photo-sensitisation of sensitive components such as riboflavin. Supplementary recovery agents were explored with only Oxyrase, which has both enzymes to degrade ROS and the ability to rapidly turn a medium anaerobic, having any significant effect. It improved the speed of recovery and increased, by up to 100-fold, the number of stressed cells recovered. Stressed cells were further studied by flow cytometry with cell sorting, based on the staining pattern from a novel fluorochrome combination, into good and poor recovery media. It was identified that within a stressed population the removal of all oxygen protected actively respiring cells the most by forcing them to generate energy from anaerobic metabolism thus avoiding any risk from accidental endogenous ROS generation. The recognition of two independent sources of oxidative stress in the routine use of conventional culture media is discussed in relation to pathogen detection and other areas of food microbiology.

Carbohydrates↗
PubMedDate not supplied

Pharmacological analysis of wine-stimulated gastric acid secretion in dogs.

Wine apparently stimulates gastric acid secretion both in man and animals, yet the underlying mechanism remains unclear. The present study was attempted to clarify the pharmacological properties involved in gastric acid secretion stimulated by wine in beagle dogs. Commercially available red or white wine, 14% ethanol, or 10% peptone meal was intragastrically administered to dogs with vagally denervated Heidenhain pouches. Gastric acid secretion was stimulated by both red and white wines (25-50 ml) for 45-60 min. While S-0509 only tended to inhibit wine-stimulated gastric acid secretion, both atropine and famotidine significantly inhibited wine-stimulated gastric acid secretion. Plasma gastrin level was not significantly increased by administration of red and white wines. Administration of 14% ethanol also stimulated gastric acid secretion, but the effect was about half of that of wine. Combined administration of wine and peptone resulted in a biphasic stimulation of gastric acid secretion. S-0509, atropine and famotidine significantly inhibited wine+peptone meal stimulation, yet the order of inhibition of cumulative acid secretion was in the order, famotidine>atropine>S-0509. It was concluded that wine stimulated gastric acid secretion in denervated dogs via acethylcholine- and histamine-dependent mechanisms, but nearly independent from the intervention of gastrin.

Animals↗
PubMed1993

15N- and 13C-labeled media from Anabaena sp. for universal isotopic labeling of bacteriocins: NMR resonance assignments of leucocin A from Leuconostoc gelidum and nisin A from Lactococcus lactis.

A procedure for universal 13C and/or 15N labeling of microbial peptides which are produced by fermentation in complex media and its application to two food-preserving bacteriocins from lactic acid bacteria are described. Isotopic enrichment of nisin A (from Lactococcus lactis) and of leucocin A (from Leuconostoc gelidum) is readily achieved using a soluble peptone derived from enzymatic hydrolysis (pepsin and chymopapain) of Anabaena sp. ATCC 27899 cells grown on sodium [13C]bicarbonate and/or sodium [15N]nitrate as sole carbon and nitrogen sources. Combustion of this peptone followed by mass spectrometric analysis indicates that 45% of the labeled carbon and 65% of the labeled nitrogen added to the Anabaena culture are utilized in the amino acids of the peptone and that the isotopic purity for both 13C and 15N remains essentially unchanged provided that the cells are grown under argon atmosphere to avoid nitrogen fixation. NMR analyses of [13C,15N]nisin A using H[13C]MQC, H[13C]MBC, 2D INADEQUATE, and H[15N]MQC techniques confirmed 1H spectral assignments previously reported for unlabeled material and readily provided carbon and nitrogen assignments. The results show that universal but not uniform 13C labeling occurs unless the nutrient source is completely isotopically enriched at high level (> or = 98%) because of differential levels of de novo amino acid synthesis. Application of NMR techniques such as TOCSY, DQF-COSY, NOESY, and H[13C]MQC to unlabeled and [13C]leucocin A afforded the complete 1H and 13C assignment. Leucocin A does not possess clearly defined conformational structure in DMSO or aqueous solutions.

Amino Acid Sequence↗
PubMed2000

Acid secretory changes in streptozotocin-diabetic rats: different responses to various secretagogues.

We examined gastric acid secretion in response to various stimuli in streptozotocin (STZ) induced diabetic rats and characterized the alteration of acid secretory responses in diabetic conditions. Animals were injected STZ (70 mg/kg, intraperitoneally) and used after five weeks of diabetes with blood glucose >350 mg/dl. Under urethane anesthesia, the experiment was performed in a chambered stomach or a whole stomach preparation, and the acid secretion was measured at pH 7.0 using a pH-stat method and by adding 100 mM NaOH. The acid secretion was stimulated by intravenous infusion of either histamine (4 mg/kg/hr), pentagastrin (60 microg/kg/hr), or carbachol (20 microg/kg/hr) or by intraluminal application of peptone solution (4%), or vagal electrical stimulation (2 msec, 3 Hz, 0.5 mA). In normal rats, acid secretion was increased in response to either histamine, pentagastrin, carbachol, peptone, or electrical vagal stimulation. In STZ diabetic rats, however, changes in acid secretion varied depending on the stimuli; the acid response to histamine remained unchanged, but the responses to vagal electrical stimulation or pentagastrin and carbachol were significantly decreased or enhanced, respectively, as compared to normal rats. Likewise, the acid response to peptone was also markedly enhanced in STZ-diabetic rats, and this response was significantly blocked by atropine and YM022 (a CCKB/gastrin antagonist) as well as famotidine in both normal and diabetic rats. Both pentagastrin and carbachol increased the luminal release of histamine in normal rats, and these responses were significantly augmented in STZ-diabetic rats. The altered acid response and histamine release induced by pentagastrin in STZ diabetic rats were partially reversed by daily injection of insulin. These results suggest that STZ-diabetic rats showed different changes in gastric acid secretion in response to various stimuli. The increased acid secretory response may be associated with an enhanced release of mucosal histamine, while the decreased response may be due to vagal neuropathy.

Animals↗