Occurence, identification and possible significance of ornithine lipid in Thiobacillus ferrooxidans

An ornithine containing aminolipid has been found in grown in ferrous sulfate medium, which was purified and estimated at four main phases of growth. GLC analysis of ornithine lipid has revealed the existence of mainly C18:1 and C22:1 fatty acids. The infrared spectra showed the existence of both amide and ester linkages in the aminolipid. The major ester linked fatty acid was C22:1. The interaction of ornithine lipid with membrane was investigated by delipidation of the membrane particles, which resulted in the perturbation of the activities of the three enzymes of iron oxidation system. The activities could be restored to the lipid depleted particles by preincubation with a dispersion of purified ornithine lipid together with coenzyme Q8. The kinetic parameters of the enzyme activities were also affected by delipidation which was significantly altered in the reconstituted particles by this lipid, thus indicating a possible role of ornithine lipid in iron oxidation system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26805/1/0000361.pd

Free and nonprotein amino acids of Tetrahymena pyriformis

Paper chromatography was used to determine 20 amino acids and related compounds present in both the free and the nonprotein forms in Tetrahymena pyriformis. The most abundant free amino acids in the cells were found to be glutamic acid, alanine, leucine-isoleucine, glycine, arginine, and lysine. Free methionine, cystine, and tryptophan were present in the smallest quantities. A relatively large proportion of aspartic acid, glycine, and glutamic acid was found in the conjugated form, while nearly all nonprotein arginine and lysine occurred in the free form. In line with values observed in other invertebrates and microorganisms, the [alpha]-amino nitrogen present in the free and the nonprotein forms constituted as high as a fifth and a fourth, respectively, of the total nitrogen of the protozoan cells.A fairly constant ratio of the amino acid content of the whole cell to that of the cellular protein was obtained, which indicated that the amino acid composition of the whole cell reflects that of the cellular protein.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32514/1/0000605.pd

Comparative analyses on medium optimization using one-factor-at-a-time, response surface methodology, and artificial neural network for lysine–methionine biosynthesis by Pediococcus pentosaceus RF-1

Optimization strategy that encompassed one-factor-at-a-time (OFAT), response surface methodology (RSM), and artificial neural network method was implemented during medium formulation with specific aim for lysine-methionine biosynthesis employing a newly isolated strain of Pediococcus pentosaceus RF-1. OFAT technique was used in the preliminary screening of factors (molasses, nitrogen sources, fish meal, glutamic acid and initial medium pH) before proceeded to optimization study. Implementation of central composite design of experiment subsequently generated 30 experimental runs based on four factors (molasses, fish meal, glutamic acid, and initial medium pH). From RSM analysis, a quadratic polynomial model can be devoted to describing the relationship between various medium components and responses. It also suggested that using molasses (9.86 g/L), fish meal (10.06 g/L), glutamic acid (0.91 g/L), and initial medium pH (5.30) would enhance the biosynthesis of lysine (15.77 g/L) and methionine (4.21 g/L). Alternatively, a three-layer neural network topography at 4-5-2 predicted a further improvement in the biosynthesis of lysine (16.52 g/L) and methionine (4.53 g/L) by using formulation composed of molasses (10.02 g/L), fish meal (18.00 g/L), and glutamic acid (1.17 g/L) with initial medium pH (4.26), respectively