To understand ion permeation, one must assign correct ionization states to titratable amino acid residues in protein channels. We report on the effects of physical and methodological assumptions in calculating the protonation states at neutral bulk pH of titratable residues lining the lumen of the native Escherichia coli OmpF channel, and five mutants. We systematically considered a wide range ...

Properties of biomolecules are often investigated using Molecular Dynamics (MD) simulations whereby atoms and molecules interact for a period of time, thus revealing the time dependent behavior of the system. Whereas the atom positions of the starting structures for such MD runs are usually derived from X-ray crystallography or NMR experiments, properties such as charges or bonds are specified ...

Organically grown products experienced a doubling in percent penetration of organic sales into retail markets during the period from 1997 to 2003; however, there is still a debate over the perceived quality advantage of organically grown fruits and vegetables. In a study focusing on commercial production of processing tomatoes, samples were analyzed from 4 growers with matched organic and conve...

This study aimed to evaluate some microbiological and physical-chemical characteristics of fermented milk beverages collected at the main supermarkets in Belo Horizonte (MG). 40 samples of the products corresponding to five distinct brands were collected. They were submitted to the following analyses: Most Probable Number (MPN) of total (30oC) and thermal tolerant coliforms (45oC), Salmonella s...

Uroporphyrinogen III synthase, U3S, the fourth enzyme in the porphyrin biosynthetic pathway, catalyzes cyclization of the linear tetrapyrrole, hydroxymethylbilane, to the macrocyclic uroporphyrino gen III, which is used in several different pathways to form heme, siroheme, chlorophyll, F(430) and vitamin B(12). U3S activity is essential in all organisms, and decreased activity in humans leads t...

Electrodialysis with monopolar ion exchange membranes was used to reduce the acid content of pineapple juice. It is an electrochemical membrane separation process in which electrically charged membranes and an electrical potential difference are used to separate ionic species in the pineapple juice from other uncharged components. Several physico-chemical (pH, titratable acidity and soluble sol...

Persimmon is a climacteric fruit and very perishable. Changes in several physiological attributes greatly affect its quality market value. The current study was designed to assess the effect of chitosan solution (an edible coating material that can improve postharvest performance) on physico-chemical persimmon during storage. fruits were harvested, cleaned then dipped various concentrations (1%...

Banana cultivars--Luvhele (MusaABB), Mabonde (MusaAAA), and Muomva-red (Musa balbisiana) --were characterized for morphological, physicochemical, and antioxidant properties. All three cultivars varied significantly (P < 0.05) in their morphology, pH, titratable acidity and total soluble solids with no significant difference in their ash content. Individual cultivars showed variations in flour s...

The complete amino acid sequence of ferredoxin isolated from a green alga, Scenedesmus species, was determined by analyses of tryptic and chymotryptic digests, and cyanogen bromide cleavage of the S-carboxymethylcysteinylferredoxin. The total number of amino acid residues is 96, one less than for the higher plant ferredoxins. It is the first chloroplasttype ferredoxin found lacking in tryptopha...