A new cellulolytic Clostridium species that was isolated from decayed grass is described. The colonies produced by this organism on cellulose agar are circular, translucent, and unpigmented and have undulate margins. The cells of this bacterium are gram-positive straight to slightly curved rods 3 to 6 km long by 0.6 to 1 pm wide and are motile; they form round, terminal spores 1.5 pm in diameter. A variety of carbohydrates are fermented by this mesophilic anaerobe. The major fermentation products from cellulose are carbon dioxide, hydrogen, ethanol, acetate, lactate, and formate. The deoxyribonucleic acid base composition is 41 mol% guanine plus cytosine. The type strain of Clostridium cellulolyticum sp. nov. is strain Hlo (= ATCC 35319).Anaerobic cellulolytic bacteria that take part in the degradation of cellulosic materials have been isolated from manure, rumen contents, and soil. In this report we describe the isolation and characterization of a new species of Clostridiurn from compost. MATERIALS AND METHODSMedia and culture techniques. The cornposition of the medium which we used was the same as the composition of the cellulose-yeast extract-salts medium (CM medium) described by Weimer and Zeikus (15), except that Na2S was omitted, the cysteine hydrochloride concentration was 1 g/liter, and the cellulose MN300 concentration was 7.5 g/liter.For solid media CM medium was supplemented with 20 g of agar (Difco Laboratories, Detroit, Mich.) per liter. The pH was adjusted to 7.5 with NaOH. This medium was prereduced by the Hungate technique (5) and was dispensed under a constant flow of N2 in 8-ml amounts (4.5-ml amounts for solid medium) into anaerobic culture tubes (16 by 125 mm; Bellco Glass, Inc., Vineland, N.J.).For enrichment cultures, we used anaerobic tubes (25 by 142 mm; Bellco) that contained 25 ml of medium.Carbohydrate media were prepared by replacing cellulose with filter-sterilized solutions of carbohydrates to give final concentrations of 7.5 g/liter. The cultures were incubated at 35°C without shaking.The anaerobic culture techniques of Hungate (5), as modified by Bryant (l), were used throughout this work.All cultures were inoculated and incubated with nitrogen as the gas.Isolation of strain HloT. Strain HloT (T = type strain) was obtained from cultured decayed grass by enrichment and isolation.Enrichment cultures were initiated by inoculating 1 to 2 g of grass from compost into anaerobic culture tubes (25 by 142 mm; Bellco) containing 25 ml of prereduced medium. After 1 week of incubation at 35"C, the cultures were heated at 80°C for 10 min, and 1 ml of each culture was then transferred to 8 ml of prereduced liquid medium.After a few days of incubation, cultures that produced * Corresponding author.discrete gas bubbles and solubilized cellulose were selected for isolation in solid medium. Serial dilutions were incubated in cellulose agar roll tubes. After 3 to 5 days, colonies which produced cleared zones of cellulose digestion were transferred individually into the liquid medium by means of a be...
Scope Synthetic emulsifiers have recently been shown to promote metabolic syndrome and considerably alter gut microbiota. Yet, data are lacking regarding the effects of natural emulsifiers, such as plant lecithins rich in essential α‐linolenic acid (ALA), on gut and metabolic health. Methods and Results For 5 days, male Swiss mice are fed diets containing similar amounts of ALA and 0, 1, 3, or 10% rapeseed lecithin (RL) or 10% soy lecithin (SL). Following an overnight fast, they are force‐fed the same oil mixture and euthanized after 90 minutes. The consumption of lecithin significantly increased fecal levels of the Clostridium leptum group (p = 0.0004), regardless of origin or dose, without altering hepatic or intestinal expression of genes of lipid metabolism. 10%‐RL increased ALA abundance in plasma triacylglycerols at 90 minutes, reduced cecal bile acid hydrophobicity, and increased their sulfatation, as demonstrated by the increased hepatic RNA expression of Sult2a1 (p = 0.037) and cecal cholic acid‐7 sulfate (CA‐7S) concentration (p = 0.05) versus 0%‐lecithin. Conclusion After only 5 days, nutritional doses of RL and SL modified gut bacteria in mice, by specifically increasing C. leptum group. RL also increased postprandial ALA abundance and induced beneficial modifications of the bile acid profile. ALA‐rich lecithins, especially RL, may then appear as promising natural emulsifiers.
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