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PubMed1996

Availability of calcium for absorption in the small intestine and colon from diets containing available and unavailable carbohydrates: an in vitro assessment.

An in vitro method simulating conditions in the small intestine and colon was used to study the effects of various carbohydrates on Ca release from basal diet (BD) containing dairy products. During enzymatic digestion of BD, 28.5 +/- 0.3% of the Ca was released. This was reduced by 3, 22 and 27% by adding bread, psyllium or pectin to BD, respectively (P < 0.05). After enzymatic digestion, the residue from BD was fermented releasing 11.9 +/- 1.2% of the Ca, a value which was significantly less than with pectin (13.7 +/- 0.9%) and greater than with psyllium (4.4 +/- 0.2%) addition. The total Ca release ranged from 26.5 +/- 0.8 to 42.2 +/- 1.0% with bread>BD>pectin>psyllium. Lactulose did not differ significantly from BD. These results suggest that carbohydrates may bind Ca and reduce its availability for absorption in the small intestine. However, if the carbohydrate is fermented, bound Ca may be released for potential absorption in the colon, whereas less fermented carbohydrates may continue to bind Ca in the colon. The in vitro method described may be useful for estimating total Ca availability. However, studies in humans are required to validate these results.

Biological Availability↗
PubMed2006

Selecting soybean meal characteristics preferred for swine nutrition.

As environmental constraints become more important issues for the animal industry, selecting feed ingredients that yield good animal performance but also minimize environmental impact of animal production becomes critical. The objective of this research was to identify which compositional features would be desirable for soybean meal to maximize nutritional value and minimize animal waste. Eight soybean samples were selected from a database of 72, such that maximal variability for CP, NDF, and ADF content was obtained. Samples were subsequently processed into meal using standardized procedures. In Experiment 1, 8 cannulated pigs were used to determine ileal digestibility following a Latin square design. In Experiment 2, 5 of the samples were used in complete feeds and 10 pigs were used in a crossover Latin square design to determine the total tract digestibility, odorants in fresh and 5-d-old manure, and ammonia emission from manure. Differences up to 6% in ileal DM digestibility and 8% in ileal CP digestibility were observed. This difference was reduced to 1.1% for total tract DM digestibility and 4% for total tract CP digestibility. Differences in odorant concentration were 3-fold and for in vitro ammonia emission were 42%. The only compositional variable with a significant effect on digestibility was stachyose, which negatively affected ileal digestibility of DM (r = -0.80, P = 0.02) and energy (r = -0.73, P = 0.04). None of the compositional variables measured affected ileal CP digestibility. Ileal CP digestibility, however, was correlated with estimated CP fermentation in the large intestine (r = -0.86, P = 0.06) and with in vitro ammonia emission after 48 h (r = -0.81, P = 0.09). In conclusion, nutritionally relevant variability exists in soy varieties. Low stachyose content is important for maximizing ileal energy digestibility of soybean meal. Although no compositional variable was identified that explained differences in ileal CP digestibility, maximizing ileal CP digestibility is of interest for maximizing the nutritional value of soybean meal and possibly for reducing ammonia and odor emissions.

Ammonia↗
PubMed1985

Characterization of limestones and their effects in vitro and in vivo in dairy cattle.

Capacities of limestones of differing particle size to neutralize acid in vitro and to modify pH and utilization of feedstuffs in vivo were compared. Acid neutralization during pH-stat titrations was faster for fine than for coarse limestone, and mixed microbial cultures were more resistant to pH change when they contained fine calcium carbonate. Diets containing 25:75 corn silage to concentrates and .95% calcium from either coarse or fine limestone were fed to rumen-fistulated heifers. Total ruminal volatile fatty acid concentrations were higher for the fine limestone treatment. Ruminal volumes, dry matter disappearance, and ruminal fluid pH and dilution rate did not differ between fine and coarse limestone treatments. Ruminal fluid volume, osmolality, ratios of acetate to propionate, and concentrations of total volatile fatty acids were unaffected in rumen-fistulated Holstein cows fed 60:40 corn silage to concentrates and either .5% calcium (control) or 1.0% calcium from either coarse or fine limestone. Ruminal pH increased .07 to .10 units with limestone supplementation. Ruminal fluid dilution and particulate turnover rates were slower for the coarse limestone than the control treatment. Differences between coarse and fine limestones in vitro were observed under some conditions in vivo, but they were not consistent.

Animal Feed↗
PubMed1979

Fermentation of 1,2-propanediol with 1,2-ethanediol by some genera of Enterobacteriaceae, involving coenzyme B12-dependent diol dehydratase.

Klebsiella pneumoniae (Aerobacter aerogenes) ATCC 8724 was able to grow anaerobically on 1,2-propanediol and 1,2-ethanediol as carbon and energy sources. Whole cells of the bacterium grown anaerobically on 1,2-propanediol or on glycerol catalyzed conversion of 1,2-diols and aldehydes to the corresponding acids and alcohols. Glucose-grown cells also converted aldehydes, but not 1,2-diols, to acids and alcohols. The presence of activities of coenzyme B(12)-dependent diol dehydratase, alcohol dehydrogenase, coenzyme-A-dependent aldehyde dehydrogenase, phosphotransacetylase, and acetate kinase was demonstrated with crude extracts of 1,2-propanediol-grown cells. The dependence of the levels of these enzymes on growth substrates, together with cofactor requirements in in vitro conversion of these substrates, indicates that 1,2-diols are fermented to the corresponding acids and alcohols via aldehydes, acyl-coenzyme A, and acyl phosphates. This metabolic pathway for 1,2-diol fermentation was also suggested in some other genera of Enterobacteriaceae which were able to grow anaerobically on 1,2-propanediol. When the bacteria were cultivated in a 1,2-propanediol medium not supplemented with cobalt ion, the coenzyme B(12)-dependent conversion of 1,2-diols to aldehydes was the rate-limiting step in this fermentation. This was because the intracellular concentration of coenzyme B(12) was very low in the cells grown in cobalt-deficient medium, since the apoprotein of diol dehydratase was markedly induced in the cells grown in the 1,2-propanediol medium. Better cell yields were obtained when the bacteria were grown anaerobically on 1,2-propanediol. Evidence is presented that aerobically grown cells have a different metabolic pathway for utilizing 1,2-propanediol.

Aerobiosis↗
PubMedDate not supplied

In vitro characterization of field isolants of Pasteurella multocida from Georgia turkeys.

Field isolants of Pasteurella multocida from fowl cholera outbreaks in Georgia turkeys were characterized by three sets of criteria: differential biochemical reactions, in vitro drug sensitivity, and serology. Of the 30 isolants studied, 28 exhibited identical biochemical patterns. These were similar to previously described patterns for turkey isolants of P. multocida. The two exceptions were isolants recovered from the same farm at different times. They differed only in ability to ferment arabinose. The isolants were generally sensitive to broad-spectrum antibiotics in vitro. The majority were also sensitive to the sulfonamides tested. Variation was sufficient, however, to warrant recommending in vitro sensitivity testing as a guide to selection of the proper therapeutic regimen in individual cases. Of the 30 isolants tested, 57% were of Heddleston's serotype 3, 3% were of his type 4, and 40% precipitated with antisera against both types 3 and 4. The large proportion of cross-reactors is unique to Georgia isolants. The biochemical patterns, drug sensitivities, and serological types had no apparent relationship to each other.

Animals↗
PubMed2003

In vitro and in vivo characterization of a novel semaphorin 3A inhibitor, SM-216289 or xanthofulvin.

SM-216289 (xanthofulvin) isolated from the fermentation broth of a fungal strain, Penicillium sp. SPF-3059, was identified as a strong semaphorin 3A (Sema3A) inhibitor. Sema3A-induced growth cone collapse of dorsal root ganglion neurons in vitro was completely abolished in the presence of SM-216289 at levels less than 2 mum (IC50 = 0.16 mum). When dorsal root ganglion explants were co-cultured with Sema3A-producing COS7 cells in a collagen gel matrix, SM-216289 enabled neurites to grow toward the COS7 cells. SM-216289 diminished the binding of Sema3A to its receptor neuropilin-1 in vitro, suggesting a direct interference of receptor-ligand association. Moreover, our data suggest that SM-216289 interacted with Sema3A directly and blocked the binding of Sema3A to its receptor. We examined the efficacy of SM-216289 in vivo using a rat olfactory nerve axotomy model, in which strong Sema3A induction has been reported around regenerating axons. The regeneration of olfactory nerves was significantly accelerated by a local administration of SM-216289 in the lesion site, suggesting the involvement of Sema3A in neural regeneration as an inhibitory factor. SM-216289 is an excellent molecular probe to investigate the function of Sema3A, in vitro and in vivo, and may be useful for the treatment of traumatic neural injuries.

Animals↗
PubMed1994

Phenotypic diversity of anaerobic glycerol dissimilation shown by seven enterobacterial species.

The anaerobic glycerol pathway was studied in seven enterobacterial species selected as representative of different behaviours in terms of anaerobic glycerol dissimilation. The presence of oxidative and reductive pathways of the dha regulon in Klebsiella pneumoniae enabled the cells to grow fermentatively on glycerol. The first two enzymes of the dha regulon (glycerol dehydrogenase type I and dihydroxyacetone kinase) represent the oxidative branch, while the latter two (glycerol dehydratase and 1,3-propanediol dehydrogenase) represent the reductive branch of glycerol fermentation. The slower utilization of glycerol by K. oxytoca was attributed to low production of 1,3-propanediol. K. oxytoca lacked glycerol dehydratase and demonstrated low 1,3-propanediol dehydrogenase activity. K. planticola and K. ozaenae differed from K. pneumoniae and K. oxytoca in lacking the ability to grow on glycerol. K. planticola lacked both enzymes of the reductive branch of glycerol fermentation, and K. ozaenae possessed glycerol dehydrogenase only. K. rhinoscleromatis and Hafnia alvei, like Escherichia coli, did not possess a dha regulon. The glycerol dehydrogenase type II of H. alvei was distinct from that of E. coli. The phenotypic diversity of anaerobic glycerol dissimilation may have taxonomic applications.

Anaerobiosis↗
PubMed2003

Effect of sodium chloride on growth and bacteriocin production by Lactobacillus amylovorus DCE 471.

A kinetic investigation of the effect of sodium chloride on cell growth of Lactobacillus amylovorus DCE 471 and amylovorin L471 production was carried out through in vitro experiments using a temperature and pH prevailing during sourdough fermentations. Sodium chloride interfered both with cell growth and bacteriocin production. Biomass formation and amylovorin L471 production decreased in the presence of increasing salt concentrations. Maximum bacteriocin activities were observed after the addition of 10 g l(-1) of NaCl, while the maximum specific growth rate reached an optimum at 5 g l(-1) of NaCl. High salt concentrations (20-40 g l(-1)) resulted in biphasic fermentation profiles. Based on these results, incorporation of 5-10 g l(-1) of sodium chloride in the water phase of type II sourdough preparations might be beneficial to enhance bacterial growth and amylovorin L471 production, and so contribute to the competitiveness of the strain in a sourdough environment.

Bacteriocins↗
PubMed2003

Utilization for lactic acid production with a new acid hydrolysis of ram horn waste.

The use of ram horn hydrolysate (RHH) as a substrate for lactic acid production was investigated using Lactobacillus casei. For this purpose, first RHH was produced. Ram horns were hydrolyzed by treating with acids (6N-H2SO4 and 6N-HCl) and neutralizing the solutions. The amounts of protein, nitrogen, ash, some minerals, total sugars, total lipids and amino acids of the RHH were determined. The effect of different concentrations (1-10% v/v) of RHH on the production of biomass, lactic acid concentration and sugar consumption was investigated, and a concentration of 6% RHH was found to be optimal. The content of lactic acid in the culture broth containing 6% RHH (44 g x l(-1)) for 26 h was 22% higher than that of the control culture broth (36 g x l(-1)). From this result, RHH was demonstrated to be a suitable supplement for lactic acid production, a use that would resolve a local environmental problem.

Animals↗
PubMed1991

Conformational stability, folding, and ligand-binding affinity of single-chain Fv immunoglobulin fragments expressed in Escherichia coli.

A fluorescein-binding single-chain Fv (scFv) was chosen as a model for the study of the physicochemical parameters associated with synthetic IgG fragments. Three such scFv proteins were designed from the primary sequences of one anti-fluorescyl monoclonal antibody (Mab 4.4.20). These were constructed with varying-length interdomain peptide linkers of between 12 and 25 residues, expressed in Escherichia coli, and the protein folding, stability, and antigen-binding characteristics were assessed. Efficient renaturation could be accomplished in vitro to yield approximately 26 mg of active scFv/L of fermentation. Scatchard analysis for fluorescein ligand binding revealed that the scFv designs come within 2-fold of the Ka = 1.99 (+/- 0.18) x 10(9) observed for the parental 4.4.20 Fab and have identical stoichiometries (n approximately 0.99). Reversible solvent denaturation studies demonstrated that the unfolding/refolding equilibria for the scFv proteins can be fit to a simple two-state model and that two of the scFv designs were found to be slightly more stable than single IgG domains (VL and CL) when assessed in terms of the free energy of unfolding, delta Gon-u, or nearly identical to other multiple domain immunoglobulin proteins such as light chains and Fab's when relative transition midpoints, Cm, are compared. Linkers which conferred conformational flexibility beyond the minimally required length of 12 residues were found to have a stabilizing effect. By these criteria of ligand-binding function and protein stability, the scFv proteins were found to be bona fide minimal replicas of their parental IgG molecules.

Amino Acid Sequence↗
PubMed1996

A partially purified beta-glucosidase from Bifidobacterium adolescentis converts cycasin to a mutagenic compound.

beta-Glucosidase was extracted from sonicated Bifidobacterium adolescentis Int-57 and partially purified by Sepharose CL-6B gel-filtration and DEAE-cellulose ion-exchange chromatography. The partially purified enzyme was confirmed to convert cycasin to a mutagen in the Ames and SOS chromotests. beta-Glucosidase negative strains were unable to activate cycasin mutagenically.

Bifidobacterium↗
PubMed1965

Invertase production by Penicillium chrysogenum and other fungi in submerged fermentation.

A study was made of Penicillium chrysogenum and some other fungi to determine the relative distribution of intra- and extracellular invertase produced by them in submerged fermentation. The proportion of each type of enzyme varied with the organism and the period of fermentation. More of the enzyme initially bound to the mycelium was released into the medium with the progress of fermentation. Differences were observed in the effects of cultural conditions on enzyme production in P. chrysogenum and Saccharomyces cerevisiae. Considerably greater quantities of enzyme were produced by P. chrysogenum and the yeast in both laboratory and large-scale fermentors when sucrose was added continuously than when the same quantities of the sugar were added initially.

Aspergillus↗