In vitro fibre fermentation of feed ingredients with varying fermentable carbohydrate and protein levels and protein synthesis by colonic bacteria isolated from pigs

in Animal Feed Science & Technology (2011), 165

An in vitro experiment was carried out using the gas technique to study the fermentation characteristics of different feed ingredients differing in their fermentable carbohydrate and protein composition ... [more ▼]

An in vitro experiment was carried out using the gas technique to study the fermentation characteristics of different feed ingredients differing in their fermentable carbohydrate and protein composition by colonic bacteria isolated from pigs. The effect on in vitro bacterial protein synthesis was also evaluated. The ingredients used were wheat bran (WB), wood cellulose (Solka-floc®, SF), peas, pea hulls (PH), pea inner fibre (PIF), sugar beet pulp (SBP), flax seed meal (FSM) and corn distillers dried grains with solubles (DDGS). The samples were pre-treated with pepsin and pancreatin and the hydrolyzed substrates were then incubated with pig faeces in a buffered mineral solution. The nitrogen source in the buffer solution (NH4HCO3) was replaced by an equimolar quantity of 15N-labeled NH4Cl, used for the determination of the rate of bacterial protein synthesis. Gas production, proportional to the amount of fermented carbohydrate, was recorded for 48 h and modelled. The fermented product was subjected to short-chain fatty acids (SCFA) analysis. The source of fibre affected the in vitro dry matter degradability (IVDMD), the fermentation kinetics and the gas production profile (P<0.05). The highest (P<0.001) IVDMD values were observed for peas (0.80) and FSM (0.70), whereas SF was essentially undegraded (0.06). The fractional rate of degradation appeared to be lower (P<0.001) for WB and DDGS (0.07 and 0.05 h, respectively) and highest for SBP (0.20 h). Peas started to ferment rapidly (lag time 1.3 h). Half gas production (T/2) was achieved sooner for PIF (8.4 h) and was the longest for DDGS (19.8 h). The total gas production was the highest for PH, followed by SF, PIF and peas (276, 266, 264 and 253 ml/g DM incubated, respectively) and the lowest for FSM and WB (130 and 124 ml/g DM incubated, respectively). There was no difference (P>0.05) in SCFA production after the fermentation of SF, P, PH, PIF and SBP (ranging from 3.8 to 4.5 mmol/g DM incubated) while WB and FSM yielded lowest (P<0.05) SCFA. The bacterial nitrogen incorporation (BNI), both at T/2 and after 48 h of fermentation was the highest (P<0.001) for PIF (18.5 and 15.6 mg/g DM incubated, respectively) and the lowest for DDGS and WB. In conclusion, peas and pea fibres had higher rates of fermentability, produced more SCFA and had high bacterial protein synthesis capacity. They thus have the potential to be included in pig diets as a source of fermentable fibre to modulate the gut environment and reduce nitrogen excretion. [less ▲]

In vitro identification of targeting ligands of human M cells by phage display

in International Journal of Pharmaceutics (2010), 394(1-2), 35-42

To improve transport of vaccine-loaded nanoparticles, the phage display technology was used to identify novel lead peptides targeting human M cells. Using an in vitro model of the human follicle ... [more ▼]

To improve transport of vaccine-loaded nanoparticles, the phage display technology was used to identify novel lead peptides targeting human M cells. Using an in vitro model of the human follicle-associated epithelium (FAE) which contains both Caco-2 and M cells, a T7 phage display library was screened for its ability either to bind the apical cell surface of or to undergo transcytosis across Caco-2 cells or FAE. The selection for transcytosis across both enterocytes and FAE identified three different peptide sequences (CTGKSC, PAVLG and LRVG) with high frequency. CTGKSC and LRVG sequences enhanced phage transport across M-like cells. When polymeric nanoparticles were grafted with the sequences CTGKSC and LRVG, their transport by FAE was significantly enhanced. These peptides could therefore be used to enhance the transport of vaccine-loaded nanoparticles across the intestinal mucosal barrier. [less ▲]

The in vitro influences of neurotensin on the motility characteristics of human U373 glioblastoma cells

in Neuropathology & Applied Neurobiology (2006), 32(6), 575-584

Astrocytic tumours are associated with dismal prognoses due to their pronounced ability to diffusely invade the brain parenchyma. Various neuropeptides, including gastrin, are able to modulate tumour ... [more ▼]

Astrocytic tumours are associated with dismal prognoses due to their pronounced ability to diffusely invade the brain parenchyma. Various neuropeptides, including gastrin, are able to modulate tumour astrocyte migration. While neurotensin has been shown to influence the proliferation of glioma cells and the migratory ability of a large set of other cell types, its role in glioma cell migration has never been investigated. Neurotensin-induced modifications to the motility features of human U373 glioblastoma cells therefore constitute the topic of the present study. We evidenced that three subtypes of neurotensin receptors (NTR1, NTR2 and NTR3) are expressed in U373 glioblastoma cells, at least as far as their mRNAs are concerned. Treating U373 tumour cells with 10 nM neurotensin markedly modified the morphological patterns of these cells and also profoundly altered the organization of their actin cytoskeletons. Pull-down assays revealed that neurotensin induced the activation in U373 cells of both Rac1 and Cdc42 but not RhoA. Scratch wound assays evidenced that neurotensin (0.1 and 10 nM) very significantly inhibited wound colonization by U373 cells cultured in the absence of serum. In addition, quantitative phase-contrast videomicroscopy analyses showed that neurotensin decreases the motility levels of U373 glioblastoma cells when these cells are cultured on plastic. In sharp contrast, neurotensin stimulates the motility of U373 cells when they are cultured on laminin, which is a pro-adhesive extracellular matrix component ubiquitously secreted by glioma cells. Our data thus strongly suggest that, in addition to gastrin, neurotensin is a neuropeptide capable of modulating tumour astrocyte migration into the brain parenchyma. [less ▲]

In Vitro Kinetics of a Newborn Rat Astroglia-Derived Neuronotoxic Activity

in Neuroscience Letters (1989), 102(2-3), 268-72

A low-molecular weight astrocyte-derived neuronotoxic activity (ANTA) was detected, using a colorimetric bioassay of cell survival, by its effect on cultured granule cells. This neuronotoxic activity was ... [more ▼]

A low-molecular weight astrocyte-derived neuronotoxic activity (ANTA) was detected, using a colorimetric bioassay of cell survival, by its effect on cultured granule cells. This neuronotoxic activity was found to be released rapidly from newborn rat astrocytes in culture upon incubation in 50 mM K+-containing growth medium. The release by astrocytes could be induced repetitively by successive incubations in high-K+ medium alternating with incubations in normal medium. Astrocytes were also found to inactivate rapidly isobutanol-extracted ANTA in normal K+-containing growth medium. Kinetic studies showed that ANTA induces a slow (greater than 12 h) degeneration of cultured granule cells. ANTA is shown here to be an intermediate of normal astrocyte metabolism and to display appropriate kinetic characteristics compatible with its proposed role in inducing part of the delayed neuronal loss that occurs after a brain injury (secondary neuronal death). [less ▲]

In vitro modelisation of prions neuroinvasion mediated by dendritic cells

Poster (2008, October)

In vitro models for the study of cartilage damage and repair

in Reginster, Jean-Yves; Pelletier, J-P; Martel-Pelletier, J (Eds.) et al Osteoarthritis: Clinical and experimental aspects (1999)

In vitro modulation of human gingival epithelial cell attachment and migration by minocycline-HCL.

in Journal of Periodontal Research (1998), 33(6), 377-85

Although the influence of tetracyclines on periodontal connective tissue cells has been the topic of many in vitro and in vivo studies, data regarding their effects on gingival epithelial cells are scarce ... [more ▼]

Although the influence of tetracyclines on periodontal connective tissue cells has been the topic of many in vitro and in vivo studies, data regarding their effects on gingival epithelial cells are scarce. The present in vitro study was designed to examine the influence of minocycline, a semi-synthetic analog of tetracycline, on human gingival keratinocyte (HGK) attachment and migration. Attachment tests were performed with HGK prelabeled by tritiated amino-acids. Increasing concentrations of minocycline (10, 50, 100 micrograms/ml) in the medium produced no significant modification of cell adhesion kinetics compared to control conditions, except for 100 micrograms/ml which statistically significantly (p < 0.05) reduced the number of attached cells beyond 6 h. A 24-h cell preincubation in 10 micrograms/ml of minocycline did not alter the kinetics of HGK attachment. Scanning electron microscopic observations of attached HGK showed that the presence of 10 micrograms/ml of minocycline in the "attachment medium" induced the production of multiple filopodial extensions. Migration tests in Boyden chambers for 40 h demonstrated that HGK preincubation for 24 h in a 10 micrograms/ml minocycline-HCl solution increased significantly (p < 0.005) cell migration towards a gradient of fetal calf serum. The presence of 10 micrograms/ml of minocycline in contact with the keratinocytes in the upper compartment of the migration chambers also produced a significant (p < 0.005) result. In contrast, the presence of minocycline in the lower compartments did not produce any chemoattractive effect. Within the limits of their significance, these results suggest that, at concentrations not beyond 50 micrograms/ml, minocycline could fasten the periodontal wound coverage by epithelial cells and allow the normal reformation of a junctional epithelium. [less ▲]

In vitro modulation of human gingival keratinocyte migration by minocycline-HCl.

Poster (1998)

In vitro modulation of keratinocyte attachment by minocycline HCl.

Poster (1994)

In vitro modulation of keratinocyte attachment to dentine by minocycline.

Poster (1996)