Histidine and arginine modulate intestinal cell restitution via transforming growth factor-ß1.

Intestinal wound healing depends on the precise balance of restitution, proliferation, and differentiation of intestinal epithelial cells (IECs). In a previous study, we revealed that IEC proliferation was suppressed under histidine deficiency. However, the role of histidine in cell restitution is poorly understood. Meanwhile, addition of arginine to basal medium enhanced IEC restitution after wounding. However, there are no reports on whether histidine or arginine deficiency influences IEC restitution. We examined the roles of histidine and arginine in IEC restitution using the rat intestinal epithelial cell-6 (IEC-6) cell line. In the present study, the cell restitution in medium lacking histidine (ΔHis) or arginine (ΔArg) was most greatly decreased among media lacking each of the 20 intravital amino acids, compared with that in medium containing all 20 intravital amino acids (Full). TGF-ß1 is a known repair factor for cell restitution. The TGF-ß1 extracellular concentration and Tgf-ß1 mRNA level were decreased in ΔHis or ΔArg. Supplementation of 10 µM histidine to ΔHis or 50 µM arginine to ΔArg recovered the decreases in both cell restitution and TGF-ß1 extracellular concentration. Phosphorylation of Smad2, a signaling molecule for the TGF-ß pathway, was decreased in ΔHis or ΔArg. Additionally, the phosphorylation of mammalian target of rapamycin, p70 ribosomal protein S6 kinase and extracellular signal-regulated kinase were decreased in ΔHis or ΔArg. The present findings suggested that deletion of histidine or arginine led to a decrease in IEC restitution through a decrease in TGF-ß1. We revealed that histidine and arginine play important roles in IEC restitution.

Decomposition of intact chicken feathers by a thermophile in combination with an acidulocomposting garbage-treatment process.

In order to develop a practical method for the decomposition of intact chicken feathers, a moderate thermophile strain, Meiothermus ruber H328, having strong keratinolytic activity, was used in a bio-type garbage-treatment machine working with an acidulocomposting process. The addition of strain H328 cells (15 g) combined with acidulocomposting in the garbage machine resulted in 70% degradation of intact chicken feathers (30 g) within 14 d. This degradation efficiency is comparable to a previous result employing the strain as a single bacterium in flask culture, and it indicates that strain H328 can promote intact feather degradation activity in a garbage machine currently on the market.

Sustainable and practical degradation of intact chicken feathers by cultivating a newly isolated thermophilic Meiothermus ruber H328.

The sustainable and practical degradation of intact chicken feathers by a newly isolated thermophilic bacterium Meiothermus ruber H328 was presented with extensive data. Aerobic cultivation with moderately thermophilic strain H328 at 55 degrees C for 6 days led to the apparently complete decay of the truly intact feathers and provided 1.89 mmol free amino acids and 7.32 mmol acid-hydrolyzed amino acids from 50 ml of culture containing 3% (w/v) intact chicken feathers. The amino acid components in the soluble fraction of the culture conspicuously agreed with those calculated from the intact feathers. This demonstrated that more than 55% of total keratin proteins were solubilized from the intact chicken feathers into the culture in the forms of free amino acid and/or soluble oligopeptide, and most of them are directly derived from the intact feathers by proteolytic digestion. Feather degradation by strain H328 surpasses that by any other microorganisms with regard to degradation efficiency, absence of requirement for pretreatment of the feathers, and product fidelity in the amino acid component. Furthermore, the culture containing the degradative products from the intact feathers was subjected to matrix-assisted laser desorption ionization mass spectrometry-time-of-flight analysis, and it was revealed that the molecular masses of the solubilized products, oligopeptides, were less than 1,000. This result allows us to investigate the bioactivities of oligopeptides derived from the degradation of chicken feathers by cultivation with strain H328 as well as the production of amino acids for feedstuffs.