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At least 757 records · Page 42Linked to original sources
PubMed1993

Identification of a major soluble protein in mitochondria from nonphotosynthetic tissues as NAD-dependent formate dehydrogenase.

In many plant species, one of the most abundant soluble proteins (as judged by two-dimensional polyacrylamide gel electrophoresis) in mitochondria from nongreen tissues is a 40-kD polypeptide that is relatively scarce in mitochondria from photosynthetic tissues. cDNA sequences encoding this polypeptide were isolated from a lambda gt11 cDNA expression library from potato (Solanum tuberosum L.) by screening with a specific antibody raised against the 40-kD polypeptide. The cDNA sequence contains an open reading frame of 1137 nucleotides whose predicted amino acid sequence shows strong homology to an NAD-dependent formate dehydrogenase (EC 1.2.1.2) from Pseudomonas sp. 101. Comparison of the cDNA sequence with the N-terminal amino acid sequence of the mature 40-kD polypeptide suggests that the polypeptide is made as a precursor with a 23-amino acid presequence that shows characteristics typical of mitochondrial targeting signals. The identity of the polypeptide was confirmed by assaying the formate dehydrogenase activity in plant mitochondria from various tissues and by activity staining of mitochondrial proteins run on native gels combined with antibody recognition. The abundance and distribution of this protein suggest that higher plant mitochondria from various nonphotosynthetic plant tissues (tubers, storage roots, seeds, dark-grown shoots, cauliflower heads, and tissues grown in vitro) might contain a formate-producing fermentation pathway similar to those described in bacteria and algae.

Amino Acid Sequence↗
PubMed1968

Penicillin-resistant variants of pneumococci.

All of the 74 strains of pneumococci isolated from human infections from 1963 to 1964 proved to be uniformly and highly susceptible to penicillin. Of these strains, 15 were identified by capsule-swelling reactions and were submitted to serial transfer in the presence of increasing concentrations of penicillin. Highly penicillin-resistant mutants were selected from 14 of the 15 strains, whereas one strain was moderately resistant. Of these mutants, 11 could still react with specific antiserum, and all of the mutants could be identified by fermentation reactions and optochin inhibition. The in vitro development of penicillin resistance in these mutants did not result in a change in cell-wall composition sufficient to diminish bile solubility. The possibility of encountering rising penicillin resistance among pneumococci, as well as the possibility that such mutants may react atypically, should be kept in mind.

Antigens↗
PubMed1993

Butyrate production from dietary fibre and protection against large bowel cancer in a rat model.

Butyrate slows the growth of cancer cells cultured in vitro. To determine the relevance of the fermentative production of butyrate in vivo, colonic butyrate concentrations were manipulated by feeding different dietary fibres and were related to tumour development in the rat dimethylhydrazine model of large bowel cancer. It has previously been shown that guar gum and oat bran, while highly fermentable, are associated with low butyrate levels in the distal colon, while wheat bran causes significantly higher concentrations. Diets containing these fibres (nominally 10% w:w) were administered for 3 weeks before, for 10 weeks during, and for 20 weeks after dimethylhydrazine administration, after which animals were killed and examined for tumours. Significantly fewer tumours were seen in the rats fed wheat bran compared with those fed guar or oat bran, and the total tumour mass was lowest in rats fed wheat bran. Rats on a 'no added fibre diet' had an intermediate tumour mass. Regression analysis, performed regardless of dietary group, showed that the concentration in stools of butyrate but not of acetate or stool volume, correlated significantly (and negatively) with tumour mass. These findings indicate that fibre which is associated with high butyrate concentrations in the distal large bowel is protective against large bowel cancer, while soluble fibres that do not raise distal butyrate concentrations, are not protective. Thus, butyrate production in vivo does bear a significant relationship to suppression of tumour formation.

Animals↗
PubMed1988

The effect of 3-methylindole on the quantity and functional quality of lung surfactant.

Acute bovine pulmonary edema is a naturally occurring lung disease caused by 3-methylindole (3MI), a ruminal fermentation product of tryptophan. Morphological and in vitro studies have suggested that 3MI causes abnormalities in phospholipid synthesis. The present study was designed to investigate the effect of 3MI on the quantity and functional quality of surfactant using the goat as an experimental model. Following intravenous infusion of 3MI, goats were killed at 6-, 18-, and 30-h intervals. The lungs were removed and intracellular surfactant, in the form of lamellar bodies, and extracellular surfactant from alveolar lavage were quantified. 3MI treatment did cause modest changes in the lamellar body phospholipid pools, decreasing the quantity of phosphatidylcholine and the proportion of palmitate in this fraction. The quantity of lavage phospholipids was not significantly affected. There was an increase in the protein content of the lavage, reflecting the presence of edema. The functional quality of the surfactant isolated from the lavage fraction was tested in vitro using a pulsating bubble surfactometer. 3MI infusion decreased the ability of surfactant to lower the surface tension of an air bubble at maximum radius and during compression.

Animals↗
PubMed2002

Comparison of the interproximal plaque removal efficacy of two powered toothbrushes using in vitro oral biofilms.

PURPOSE: To compare the efficacy of interproximal plaque removal beyond the bristles by two electric toothbrushes, the new Sonicare Elite and Braun Oral-B 3D, in an in vitro model replicating the brushing of interproximal plaque as would occur in vivo. MATERIALS AND METHODS: Oral biofilms were grown, in vitro, in a constant-depth film fermenter on a hydroxyapatite (HA) disc substratum. Brushing experiments were conducted in a brushing machine representing the brushing of interproximal plaque between mandibular molars. The HA discs with oral biofilms were located a minimum of 1.6 mm away from the bristles. The efficacy of plaque removal was assessed by enumeration of the percentage of viable bacteria removed from the biofilms by 5 seconds of brushing with the brush motors either activated or inactivated. RESULTS: In the activated state, both brushes removed a significantly higher percentage of plaque bacteria compared to the inactive brushes (Braun, P = 0.002; Sonicare, P = 0.005). The percentage of plaque bacteria removed by the Sonicare Elite (32.23%) beyond the bristles was significantly greater (P = 0.012) than that removed by the Braun Oral-B 3D (9.48%) in this model system.

Adult↗
PubMed2004

Appropriate use of the carbapenems.

The carbapenems are a group of broad-spectrum beta-lactam antibiotic agents of which there are three parenteral preparations currently available in South Africa, namely imimpenem/cilastatin, meropenem and ertapenem. Owing to the fact that imipenem/cilastatin and meropenem have a broad spectrum of activity that includes Pseudomonas and Acinetobacter species, they are ideal antibiotics for treatment of severe nosocomial infections. In contrast, ertapenem has limited in vitro activity against the latter non-fermentative gram-negative bacteria and is therefore more suitable for the treatment of certain severe community-acquired infections. This statement arises out of concerns about the general abuse of antibiotics such as the carbapenems, with the primary intention of highlighting the appropriate use of these agents.

Anti-Bacterial Agents↗
PubMed1996

In vitro inhibition of microbial methane production by 9,10-anthraquinone.

Monensin, 2,2-dichloroacetamide, and 9,10-anthraquinone were incubated for 24 h in ruminal fluid and buffer with 100:0, 50:50, and 10:90 forage-concentrate diets. Monensin (.5 ppm of the fluid) increased (P < .05) the molar proportion of propionate in the 50 and 100% forage diets but not in the high concentrate diet. At the same level of addition, 2,2-dichloroacetamide increased (P < .05) the molar proportion of propionate only in the 50:50 forage-concentrate diet. Relative to control cultures, monensin and 2,2-dichloroacetamide numerically decreased methane production in the 10 and 100% forage diets and decreased (P < .05) methane in the 50% forage diet. Hydrogen production was unaffected by treatment. Lack of an effect on fermentation end products in the high concentrate diet was probably a result of the low dose levels. In general, increasing levels of 9,10-anthraquinone (.5, 1.0, and 5.0 ppm) reduced total VFA concentration and the molar proportion of acetate, and increased propionate, butyrate and valerate. Increasing levels of 9,10-anthraquinone caused linear and quadratic decreases (P < .05) in methane production, and increases (P < .05) in hydrogen. There were no consistent effects on ammonia concentration in culture fluid from any of the compounds. In continuous culture of a 10:90 forage-concentrate diet, addition of 9,10-anthraquinone (10 ppm of the fluid/12 h) caused changes similar to those observed in batch culture with the exception of a decreased (P < .05) molar percentage of propionate, which may have been due to the high dose. The data are interpreted to indicate that 9,10-anthraquinone has the ability to alter in vitro microbial fermentation.

Acetamides↗
PubMed1995

Natural fermentation of lentils. Influence of time, concentration and temperature on protein content, trypsin inhibitor activity and phenolic compound content.

Lentil (Lens culinaris var. vulgaris) flour was naturally fermented for 4 days at different temperatures (28 degrees C, 35 degrees C and 42 degrees C) and concentrations (79 milligrams, 150 milligrams and 221 milligrams). Samples were analysed to establish the changes of total protein content and in vitro protein digestibility, trypsin inhibitor activity (TIA) and phenolic compound content during natural fermentation of lentils. The preparation of lentil flour suspensions to be fermented caused a slight increase in total protein and in vitro protein digestibility content, a decrease of TIA and a sharp decrease the tannin/catechin ratio. During the whole fermentation procedure, the minimum initial lentil concentration and temperature used (79 milligrams, 28 degrees C) achieved the maximum protein content and the lowest tannin/catechin ratio. The TIA was more affected by temperature than by concentration, and a 62.5% reduction was observed at 42 degrees C and 79 milligrams.

Catechin↗
PubMed1985

Intestinal metabolism of a random-bonded polyglucose bulking agent in humans: in vitro and in vivo studies of hydrogen evolution.

In vivo and in vitro experiments were conducted to determine the extent of intestinal fermentation of polydextrose, a random-bonded glucose polymer proposed as a low-calorie bulking agent in weight-reducing diets. The evolution of hydrogen gas was the index of bacterial fermentation. Oral ingestion of 15 gm polydextrose by healthy volunteers produced a flat breath hydrogen response, equivalent to that of glucose, and significantly less than that of lactulose. In vitro incubation of a polydextrose solution with fecal homogenates produced 24.8% of the hydrogen production of a comparable glucose solution. When either milk or lactose-hydrolyzed milk containing 18 gm intrinsic carbohydrate was mixed with 18 gm polydextrose, a significantly greater breath hydrogen excretion was observed as compared with the respective beverages alone. There is minimal in vivo fermentation of polydextrose when consumed alone, but when mixed into foods it may produce carbohydrate malabsorption or itself be more readily fermented.

Adult↗
PubMed2005

Effect of dairy products on the lifetime of Provox2 voice prostheses in vitro and in vivo.

BACKGROUND: Reduction of biofilm formation on tracheoesophageal voice prostheses by certain dairy products might extend their clinical lifetime. The purpose of this study was to determine the influence of certain dairy products on voice prosthetic biofilms and lifetimes in vitro and in vivo. METHODS: The in vitro results were accomplished using an artificial throat. The lifetimes of Provox2 prostheses were evaluated in a patient group that daily consumed the evaluated products. RESULTS: Buttermilk and Yakult Light fermented milk decreased the amount of bacteria on voice prostheses but stimulated yeast prevalence in vitro. Concurrently, lifetimes of voice prostheses in patients consuming buttermilk were not significantly different, whereas patients consuming Yakult Light fermented milk drink had a significantly (p < .01) increased prosthesis lifetime by a factor of 3.76. CONCLUSION: Yakult Light fermented milk drink reduced biofilm formation on Provox2 prostheses in vitro and in vivo and significantly increased prosthesis lifetime. In vivo, no significant effects were observed for patients consuming buttermilk.

Aged↗
PubMed1995

Influence of starch fermentation on bile acid metabolism by colonic bacteria.

Secondary bile acids (BA) may be involved in the pathogenesis of colorectal cancer. In vivo, starch malabsorption has been shown to reduce fecal excretion of secondary BA. The present in vitro study was performed to investigate the effect of starch fermentation on BA metabolism by colonic bacteria. Fecal samples of healthy volunteers were incubated in anaerobic batch cultures for 48 hours with the primary bile acids cholic (0.6 g/l) and chenodeoxycholic acid (0.4 g/l). Media were starch free or enriched with starch (10 g/l). The pH was controlled and held at 6 or 7. In the starch-free incubations, secondary BA were rapidly formed, and degradation of primary to secondary BA was complete within 24 hours. The formation of secondary BA was partially inhibited by the addition of starch to the media. This effect was stronger at pH 6 than at pH 7. Starch was rapidly and completely fermented. In conclusion, this study showed that formation of secondary BA by fecal bacteria is inhibited when starch is simultaneously fermented, an effect that is mainly, but not completely, explained by reduction of pH.

Bacteria, Anaerobic↗
PubMed1999

Nutritional benefits of specialty grain hybrids in beef feedlot diets.

The study of grain hybrids with faster or more extensive rates of ruminal starch fermentation has been a key research area. Because grain sorghum starch is generally regarded as less accessible to enzymatic degradation than starch in other grains, it has received the greatest research emphasis. However, all grains have been evaluated to some extent. Grain sorghum hybrids appear to be more variable in digestibility, in vitro and in vivo, and in rate of starch fermentation than are corn hybrids. The greater variation may be partially because grain sorghum hybrids are developed and evaluated under more stressful environmental conditions (high temperature and limited water conditions) than are corn hybrids. In vitro and in vivo studies indicate that differences in grain hybrids exist, but these differences may not totally explain differences in cattle performance. The response to feeding high-lysine corn to cattle has been variable. Although high-lysine corn supplies more lysine in the diet, lysine flow to the abomasum was not increased. Hybrids selected for increased lysine content have been shown to have faster in vitro rates of starch digestion, suggesting that improvements in animal performance may be related to the indirect selection for improved energy utilization. In one study in which high-oil corn was evaluated, feed conversion was not improved compared with a control corn diet. At the present time additional studies in which other genetic modifications of grain hybrids are evaluated are in progress, but the results have not been published.

Animals↗
PubMed1994

Nutritional improvement of lentils, chick pea, rice and wheat by natural fermentation.

Effect of natural fermentation process (4 days) on the non-protein nitrogen, crude and true protein, amino acids content and in vitro digestibility of two kinds of legumes (lentils and chick pea) and two kinds of cereals (rice and wheat) was investigated. Non-protein nitrogen increased significantly (p < 0.001) in the fermented products. Little increase has occurred in the crude protein while no significant change was observed in the fermented true protein samples. It was observed that methionine and cystine which are considered the limiting amino acids in legume seeds were close to those of FAO/WHO patterns. Also, lysine content (the first limiting amino acid in cereals was higher in fermented rice than that of FAO/WHO pattern. Moreover, fermentation process improved significantly, the in vitro digestibility of both legume and cereal products.

Amino Acids↗
PubMed1977

Aerobic and anaerobic fermentation of glucose by Echinostoma liei.

Echinostoma liei was incubated in vitro aerobically and anaerobically with various species of 14C glucose. From the recovery of isotope in the respired CO2, it appeared that glucose was incompletely oxidized. The major portion of the CO2 arose from the 3 and 4 carbons of glucose. In addition to CO2, a number of volatile fatty acids accumulated as end-products both aerobically and anaerobically. Lactate and succinate were also isolated. Of these, n-valerate was recovered in the highest concentrations. Qualitatively, the same products were demonstrated after both aerobic and anaerobic incubations, but quantitatively considerably more fatty acids accumulated anaerobically.

Aerobiosis↗