Characteristics of the simplest type of bulk-incubation artificial rumen for the production of volatile fatty acids.
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Animal Feed↗
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Results for “In vitro fermentation”
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n-Butyrate mediation of ganglioside expression of human and murine cancer cells demonstrates relative cell specificity.
1. n-Butyrate, a short chain fatty acid produced by colonic fermentation, induces differentiation in human neoplastic cell lines, and reduces expression in vitro of a sialyltransferase that glycosylates N-linked glycoproteins in hepatoblastoma cells. Gangliosides are amphipathic, sialylated glycosphingolipids that undergo profound changes in many transformed cells and may protect neoplastic cells from host immune surveillance. Colonic mucosal cells are exposed to luminal short-chain fatty acid concentrations of up to 80 mmol/l, and there is some evidence that short-chain fatty acids may alter ganglioside expression in colon cancer cells. 2. Because of the importance of gangliosides in cancer pathogenesis, we investigated the effects of n-butyrate on ganglioside expression of colonic (human and murine) and non-colonic cancer cells. 3. Three separate colon cancer cell lines (LS174T, T84 and MCA-38), when butyrate treated, demonstrated striking amplification of specific individual gangliosides. However, the total lipid-bound sialic acid content of gangliosides of butyrate-treated LS174T cells diminished. In contrast to earlier reports, n-butyrate did not mediate expression of all gangliosides and specifically did not mediate expression of GM3. This effect persisted even after removal of butyrate. 4. In contrast, exposure of extracolonic cells to butyrate, including cervical cancer (HeLa) and laryngeal cancer (HEp-2) cell lines in this study and hepatoblastoma cells (Hep G2) in our previous work, caused no detectable changes in ganglioside expression. 5. In conclusion, our results indicate a relative tissue specificity of butyrate-mediated alterations in ganglioside expression that is not universal but is limited to specific gangliosides.
Animals↗
Anti-cancer effects of butyrate: use of micro-array technology to investigate mechanisms.
Epidemiological evidence suggests that a high intake of resistant starch and NSP protects against colo-rectal cancer. The mechanisms underlying this protection are thought to be mediated by the short-chain fatty acid butyrate, which is present in the colonic lumen in millimolar concentrations as a result of bacterial fermentation of carbohydrates that have resisted digestion in the small intestine. In vitro studies have shown that butyrate displays a host of chemo-preventative properties including increased apoptosis, reduced proliferation, down regulation of angiogenesis, enhanced immunosurveillance and anti-inflammatory effects in colo-rectal cancer cell lines. However, the molecular mechanisms underlying the apparent chemo-preventative actions of butyrate are largely unknown. The evidence supporting the role of butyrate as an anti-cancer agent is reviewed, with particular emphasis on those studies that have attempted to elucidate the mechanism of action of butyrate. Our understanding of the mechanistic action of butyrate and its role in cancer prevention is likely to advance considerably in this post-genomic era with the application of genomic and proteomic technologies. Studies are described that have used gene array and proteomic techniques to investigate the response of colo-rectal cancer cells to butyrate. These pioneering studies illustrate the potential of these technologies to help characterise the molecular responses of the cancer cell to butyrate, and to define the role of butyrate (and other nutrients) in the prevention of colo-rectal cancer.
Animals↗
Long-term cultivation of certain rumen protozoa in a continuous fermentation system supplemented with sponge materials.
Inert polyurethane-sponge cubes were added to an 'artificial rumen' fermenter. With crushed barley as protozoal substrate this system maintained a population of Entodinia in both substrate bags and sponge cubes for 64 d in numbers (1 X 10(6)/ml) comparable with those found in vivo. This culture was more tolerant of variations in mechanical agitation and size and shape of substrate bags than a similar culture without the sponge cubes. The extent of protozoal sequestration, 2 h after feeding, on to the sponge cubes as well as on to acetone-treated hay was evaluated. The bags of acetone-treated hay and barley, and those of sponge cubes and barley could sequestrate the protozoa to the same extent as normal hay and barley. Based on the results of the short-term experiments and those of the long-term experiment with sponge cubes, a polyurethane-sponge wall was added to the inside of the fermenter. This system maintained a varied protozoal population including large protozoa, holotrichs and Entodinia with a normal fermentation. The molar percentages of butyrate in the total volatile fatty acid (VFA) in each part of the fermenter with a sponge wall were higher than those in a fermenter without a sponge wall, suggesting that there was high protozoal activity related to the sponge wall. These results show that the introduction of the sponge wall to the fermenter produced an enlargement of the area for protozoal sequestration and a suitable micro-habitat for the maintenance of Entodinia , large protozoa and holotrichs .
Animals↗
Studies on the fate of the glucosyl moiety of sucrose metabolized by Streptococcus mutans.
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Adhesiveness↗
The effect of fluoride on the stability of oral bacterial communities in vitro.
An in vitro model system has been used to study the combined influences of fermentable carbohydrate, pH, and fluoride on the stability of complex oral microbial communities. The pH generated from carbohydrate pulses rather than the availability of substrate per se was responsible for the enrichment of the cariogenic species S. mutans and L. casei. The addition of sub-MIC levels of sodium fluoride (1 mmol/L; 19 ppm) reduced both the rate of acid production and the fall in terminal pH from glucose pulses, thereby enabling pH-sensitive bacteria, including many Gram-negative species, to persist. Furthermore, the combination of even a moderately-low environmental pH (ca. pH 5.0) with a low level (1 mmol/L) of fluoride was able to prevent S. mutans from out-competing other species and resulted in its proportions within the bacterial community remaining low. By this mechanism, fluoride could make a significant contribution to preventing dental caries.
Bacteria↗
Effects of enzyme supplementation of a total mixed ration on microbial fermentation in continuous culture, maintained at high and low pH.
A dual-flow continuous culture system was used to investigate the effects of pH and addition of an enzyme mixture to a total mixed ration (TMR) on fermentation, nutrient digestion, and microbial protein synthesis. A 4 x 4 Latin square design with a factorial arrangement of treatments was used, with four 9-d periods consisting of 6 d for adaptation and 3 d for measurements. Treatments were as follows: 1) high pH with control TMR, 2) high pH with TMR treated with enzyme, 3) low pH with control TMR, and 4) low pH with TMR treated with enzyme. Ranges of pH were 6.0 to 6.6 and 5.4 to 6.0 for high and low, respectively. Fermenters were fed twice daily a TMR consisting of 30% alfalfa hay, 30% corn silage, and 40% rolled corn (DM basis). The silage was milled fresh and the TMR was fed to the fermenters in fresh form (64% DM). The enzyme mixture was a commercial product of almost exclusive protease activity; it was applied daily to the fresh TMR and stored at 4 degrees C for at least 12 h before feeding. Degradability of OM, NDF, ADF, and cellulose was decreased (P < 0.05) by low pH. Hemicellulose and protein degradation were not affected by pH. Enzyme addition increased (P < 0.01) NDF degradability (by 43% and 25% at high and low pH, respectively), largely as a result of an increase in hemicellulose degradation (by 79% and 51% at high and low pH, respectively). This improvement was supported by an increase (P < 0.05) in the xylanase and cellulase activities in the liquid phase of the fermenter contents. Total VFA were decreased (P < 0.05) by low pH, but were not affected by enzyme addition. Total bacterial numbers were increased (P < 0.03) at low pH and tended (P < 0.13) to increase with enzyme addition. Cellulolytic bacteria in effluent fluid were decreased (P < 0.02) at low pH but were unaffected by enzyme addition. Despite a large increase (P < 0.001) in protease activity, protein degradation was only numerically increased by enzyme addition. Microbial protein synthesis was higher (P < 0.10) at high pH but was not affected by enzyme addition. Methane production, expressed as a proportion of total gases, was decreased (P < 0.001) at low pH but was not affected by enzyme addition. It is concluded that it is possible to adapt the continuous culture system to use fresh feeds instead of dried feeds. Overall, the results indicate that the enzyme product used in this study has a potential to increase fiber degradability without increasing methane production.
Animal Feed↗
Effects of replacing dietary starch with sucrose on ruminal fermentation and nitrogen metabolism in continuous culture.
A dual-effluent continuous-culture system was used to evaluate the effects of partially replacing cornstarch with sucrose in a total mixed ration on ruminal fermentation and N metabolism. The 4 treatments were 0 (control), 2.5, 5.0, and 7.5% sucrose and, respectively, 7.5 (control), 5.0, 2.5, and 0% cornstarch in a total mixed ration containing 20% corn silage and 40% alfalfa silage. Fermenters were fed 4 times a day during four 9-d periods with sampling beginning on d 6. Replacing cornstarch with sucrose did not alter ruminal pH (5.97), total volatile fatty acids (VFA) (104.4 mmol/L), or the acetate to propionate ratio (2.16); however, branched-chain volatile fatty acids were higher for the control treatment compared with the 7.5% sucrose treatment. Five hours postfeeding, sucrose treatments significantly altered molar proportions of all volatile fatty acids, and acetate-to-propionate and glucogenic-to-lipogenic ratios. Digestibility of dry matter and N were not affected by treatment, but digestibility of total non-structural carbohydrates was increased with sucrose treatments. A quadratic effect was noted for neutral detergent fiber (NDF) digestibility as sucrose replaced starch. A higher NDF digestibility (66.1 vs. 59.9%) was observed for the 7.5% sucrose treatment compared with the other 2 sucrose treatments. Levels of ammonia N were within an acceptable range to support microbial protein synthesis and did not differ among treatments (mean=9.23 mg/dL). Sucrose inclusion in the total mixed ration did not affect bacterial N synthesis. Results indicate that (at the levels tested in this study) inclusion of sucrose in the diet when rumen-degradable protein is adequate does not affect ruminal fermentation.
Animal Feed↗
Effect of pH and energy spilling on bacterial protein synthesis by carbohydrate-limited cultures of mixed rumen bacteria.
Rumen contents were obtained from a cow fed 2.5 kg concentrates and 2.5 kg timothy hay twice daily, and the mixed rumen bacterial inoculum (pH 6.3) was separated from large feed particles and protozoa by centrifugation. Bacteria were incubated in artificial media at pH 6.7 and 6.0. When starch, sucrose, cellobiose, xylan, pectin, or a mix of carbohydrates were provided to pH 6.7 incubations at 1 mM/h for 10 h, fermentation was carbohydrate-limited, less than 20% of the carbohydrate was converted to lactate, molar ratio of methane to hexose fermented was as great as 49%, and pH remained constant. When initial pH was lowered to 6.0, methane production was nearly eliminated, volatile fatty acid production was reduced, and there was a small decrease (less than .5) in final pH. At pH 6.0, lactate production was increased in all incubations except xylan and pectin, and pH had a greater effect on acid production than the type of carbohydrate provided. Bacterial protein synthesis was reduced 34 to 69% when initial pH was 6.0, but these reductions were greater than decreases in carbohydrate utilization, increases in lactate, and associated decreases in adenosine 5'-triphosphate production. Because less adenosine 5'-triphosphate was used for protein synthesis, it appeared that low pH diverted energy to nongrowth functions.
Animals↗
Calcium alginate-immobilized cultures of lactic Streptococci are protected from bacteriophages.
Calcium alginate-immobilized cultures of lactic streptococci were grown in milk and assessed for their sensitivity to homologous bacteriophage, proteolytic activity, and acid production. Immobilized cultures of Streptococcus lactis C2 and Streptococcus cremoris HP were protected from attack by bacteriophage due to the exclusion of phage particles from the gel matrix. These cultures were also functionally proteinase-deficient when immobilized in calcium alginate beads and grown in milk. Acid was produced by immobilized cultures at a lower rate than cells freely suspended in milk due in part to the inability of the immobilized cells to hydrolyze milk proteins. Agitation of immobilized cultures slightly increased acid production, suggesting that diffusional limitations of substrate into the beads contributed to decreased acid production. Use of immobilized cultures of lactic streptococci in certain dairy fermentations may be advantageous due to the protection of these cultures from attack by virulent bacteriophage.
Alginates↗
Effect of thiazinotrienomycin B, an ansamycin antibiotic, on the function of epidermal growth factor receptor in human stomach tumor cells.
Thiazinotrienomycin B (TT-B), an ansamycin isolated from fermentation broths of Streptomyces sp. MJ672-m3, inhibited the growth in vitro of human stomach tumor SC-6 cells over 10 times more strongly than the growth of other human tumor cells, such as HeLa (cervix), T24 (bladder) and LX-1 (lung). The extent of growth inhibition by TT-B of SC-6, but not of LX-1 nor T24, was lowered in a competitive manner by raising serum concentrations in the culture medium. TT-B inhibited the cell cycle progression of SC-6 at an early stage of the progression from G0/G1 to S. The inhibition was again competitive with serum concentrations in the culture medium. No direct inhibition of DNA synthesis was observed at the concentration range which caused the cell cycle arrest. TT-B and anti-epidermal growth factor receptor (anti-EGFR) were antagonistic to each other in inhibiting the cell cycle progression of SC-6 from G0/G1 to S, suggesting that the two compounds share the same target, EGFR. The kinase activity of EGFR was little inhibited by TT-B in a cell-free system.
Anti-Bacterial Agents↗
Nosocomial bloodstream infection in pediatric patients: Siriraj Hospital, Bangkok; 1996-1999.
A retrospective study on nosocomial bloodstream infection (NBSI) in pediatric patients hospitalized at Siriraj Hospital from January 1996 to December 1999 was performed. Of the 18,087 blood specimens sent for culture, 533 (3%) were positive for organisms after 72 hours of hospitalization and were defined as NBSI. The rate of NBSI detected in blood culture specimens was highest among neonates (5.2%). Gram-positive cocci and gram-negative rods caused NBSI in an equal proportion (46% and 44% respectively) and Candida caused 10 per cent of NBSI. Coagulase-negative staphylococci was the most common pathogen followed by K. pneumoniae and Enterobacter. Antibiogram showed that 15 of the 35 (43%) S. aureus identified were methicillin-resistant. Only 35-38 per cent of Enterobacteriaceae were sensitive to cefotaxime or ceftazidime. Cefoxitin was still effective against 95 per cent of K. pneumoniae. Compared with other third generation cephalosporins, combination of cefoperazone and betalactamase-inhibitor (sulbactam) possessed an increased in vitro efficacy against K. pneumoniae, Enterobacter, E. coli, Acinetobacter and non-fermentative gram-negative rods. Resistant rate of amikacin among all gram negative rods was 25-69 per cent. Ciprofloxacin sensitivity varied from 62-100 per cent among all gram-negative rods. Imipenem was excellent against all gram-negative rods with the sensitivity of 80-100 per cent. Epidemiological data of this study is important for the decision of the appropriate empirical antimicrobial treatment in our hospital.
Bacteremia↗
Resistant starch as related to companion animal nutrition.
Companion animal diets may contain up to 50% starch, derived from cereal grains. The amount of resistant starch (RS) in an ingredient depends on the origin and form of the ingredient and on the processing conditions to which the ingredient has been exposed. Extrusion has proven to be a means of optimizing utilization of starch by companion animals. Although the RS fraction of starch typically decreases by extrusion, retrogradation can result in increased concentrations of this fraction. Limited research exists regarding the effects of RS in companion animal nutrition and gastrointestinal health. Existing in vitro and in vivo research indicates that certain RS sources are readily fermented in the large bowel, producing short-chain fatty acids, whereas others are less fermentable, resulting in excellent laxation properties. Feeding dogs a diet high in RS may result in an increase in fecal bulk due to an increased excretion of microbial matter in those cases where RS is highly fermentable, or to indigestibility of the RS source in other cases. RS has a role to play as a potential proxy for dietary fiber, especially for those companion animals fed diets high in protein and fat and devoid of traditional dietary fiber.
Animal Feed↗
[Antitumor activity of FK973 for malignant gliomas and its assessment for normal brain cells].
FK973, a novel antitumor antibiotic, was obtained as a fermentation product of Streptomyces sandaensis. FK973 had excellent cytotoxic effects against in vitro cultured human glioblastomas, medulloblastomas, and murine glioma (203 glioma) cells. The antitumor effects were also well observed against ACNU resistant glioma cells. FK973 did not go through the blood-brain barrier. The median survival time (MST) of MG models treated with FK973 was 21 days. On the other hand, the MST of the control group was 15 days. In the in vitro assessment against neural disturbance, FK973 showed a little disturbance of murine brain cells but less toxic than ADM. In the in vivo neurotoxicity examination, FK973 showed no clear damage to the neural cells and myelin sheaths.
Animals↗
[Determining the conditions for stimulation of levorin biosynthesis in the presence of succinic acid].
Conditions promoting the stimulating effect of succinic acid on biosynthesis of levorin were determined. The optimal concentration of succinate was shown to be equal to 0.05-0.3 per cent and the best time for the addition was before inoculation. The most pronounced stimulating effect was observed when the initial pH value of the fermentation medium was equal to 7.0. The important role of ammonium nitrogen in manifestation of the succinic acid stimulating effect on biosynthesis of levorin was suggested.
Anti-Bacterial Agents↗
[Isolation of 5-benzyl hydroxytryptophan enantiomers by using microbial aminoacylase].
The process of asymmetric deacylation of an acetyl derivative of 5-benzyl hydroxytryptophan racemate in the presence of native microbial aminoacylase was studied. The effect of pH, temperature, concentration of the enzyme and substrate were investigated. Conditions for preparation and isolation of individual amino acids were defined by optimization of N-Ac-DU-5-BOT hydrolysis.
5-Hydroxytryptophan↗
In vitro and in vivo characterization of avian Escherichia coli. II. Factors associated with pathogenicity.
The pathogenicity of 197 Escherichia coli isolates obtained from clinically affected commercially grown broiler chickens and normal hatchery chicks was assessed by inoculating day-old broilers intratracheally. The degree of pathogenicity (high, intermediate, low) was judged according to mortality and lesions occurring within 7 days following inoculation. Serotype, metabolic activity, motility, and in vitro antibiotic sensitivity of each isolate were evaluated and related to pathogenicity. Seventy-five of the isolates of high to intermediate pathogenicity belonged to serogroup O2, O78, or O35. In addition, 51 pathogenic E. coli isolates could not be serotyped, and several had multiple serotypes. Most isolates had similar metabolic activity, as determined by amino acid decarboxylation and carbohydrate fermentation, regardless of pathogenicity. An exception was the fermentation of adonitol, which occurred more frequently with the highly pathogenic strains. Motility and in vitro antibiotic sensitivity were not related to pathogenicity. An age-associated resistance to intratracheal E. coli administration occurred by 15 days of age in uncompromised birds. Relative susceptibility of birds older than 2 weeks to intratracheal and/or intravenous E. coli inoculation could be increased by prior exposure to pathogenic reovirus 1733, adenovirus 3167, or infectious bursal disease virus (IBDV). Birds infected with IBDV at 3 weeks failed to clear apathogenic and pathogenic E. coli from circulating blood.
Aging↗
Evaluation of the nutritional quality and acceptability of sorghum-based tempe as potential weaning foods in Tanzania.
Six types of sorghum (Sorghum bicolor)-based tempe were developed by blending with various combinations and quantities of either bambara groundnut, sesame, cowpea, pigeonpea, common bean, mungbean, soybean, or groundnut (peanut) seeds. Their mixtures were then soaked and solid-state fermented by Rhizopus oligosporus to produce tempe. Soaking resulted in the loss of minerals. Mould fermentation did not change the proximate and mineral composition, but increased the in vitro protein digestibility by 10 to 14.1%. Tempe processing reduced the tannin content by 30.4 to 94.0%. The protein content of tempe ranged from 16.0 to 18.6%; the amino acid score, 63.0 to 69.0%; protein energy, 14.2 to 16.8%; net dietary protein energy, 7.3 to 8.4%; and total energy, 416.0 to 441.0 Kcal/100 g of tempe. The developed tempe had protein quality and energy recommended for weaning foods. The deep-fried snacks were mildly acceptable. More research work and promotion are proposed in order to improve the acceptability of sorghum-based tempe as potential weaning or supplementary foods in Tanzania.
Edible Grain↗