It is often used in the selective identification of enteric bacteria including Salmonella and Shigella. The TSI agar has glucose, lactose and sucrose as the sources of carbohydrates. Phenol red is the acid base indicator incorporated in the medium. The TSI medium indicates whether the bacteria ferments glucose only, or lactose and sucrose with or without production of gas. Nitrate serves as a source of nitrogen for many bacteria.
MATERIALS AND METHODS Bacterial strains and culture conditions Two S. aureus strains were used in the present study; S. aureus 8325-4 (SigB-) and SH1000 representing a SigB+.strain. Overnight cultures were grown in Luria Broth (LB) at 37°Cwith shaking at 150 rpm. Exposure to antibiotics was carried out as detailed below. Antibiotics Ciprofloxacin were purchased from Sigma-Aldrich CO. 10 mg/ml stock solution of antibiotic were prepared freshly with 0.1N HCl and stored at -20°C. During the experiment we diluted with sterile water 1:10 and 1:100 depending on the different drug concentration.
2.2.Yeast cell preconditioning and inoculum preparation 1 g dry weight of yeast was resuspended in 100 mL of deionized water in an Erlenmeyer flask of 250 mL volume, at 30–35°C, for 30 min with NaCl 6% w/v. Inoculum for experimental fermentations was prepared
(76.8μm) The product was analyzed periodically during storage for parameters like moisture, acidity, water activity, colour, TBARS, FFA, Browning Index etc. The kinetics of quality changes w.r.t carotenoid degradation was studied using zero order and first order reaction kinetics. 4.1. Physico-chemical analysis of avocado milk shake powder The initial analysis of avocado milk shake powder showed acidity 0.171±0.01 (% lactic acid), water activity (0.253), pH
100ul of Folin reagent was added to the wells and incubated for another 20 minutes. The absorbance was measured at 630-700nm. A standard curve of absorbance vs. protein concentration was plotted and the protein concentration in the diluted sample and the total percentage of activity were
To indicate the separation effect for different ratio of p-xylene to methyl acetate more clearly, Fig. 4 shows the dependence of selectivity on the water/acetic acid mass ratio in the initial mixture for various different ratios of p-xylene to methyl acetate in the initial mixture. These results reveal the general capability of mixed solvent to extract acetic acid from the aqueous phase at different feed composition. As mentioned earlier, methyl acetate has been put up in this industrial operation, since it was available as the byproduct of terephthalic acid production. As can be seen in Fig.4, a higher ratio of p-xylene to methyl acetate can produce higher selectivity of acetic acid against water.
HPLC-grade methanol (15 mL) was added to a quantity of the powdered tablets equivalent to one tablet. This solution is sonicated for 20 min. Filtration through Whatman No. 1 filter paper followed by quantitative transfer of the filtered solution into 25 mL volumetric flask and then dilution was made to volume with methanol. A further dilution was made to reach final concentration of 102.8 µg/mL, 97.2 µg/mL for VAL and SAC respectively.
The sample was transferred to a 250 ml conical flask kept in water bath for alkali treatment. 75 ml of 17.5% caustic soda was measured using a measuring cylinder at 20°C. 15 ml of 17.5% NaOH was added and fibres were macerated gently with a flattened glass rod for 1 minute. 10 ml more NaOH was added and the solution was mixed for 45 seconds. 10 ml NaOH was again added and mixed for 15 seconds to make lump free slurry.
Cell culture Caco-2 cell was provided (passage 32–36) by School of Pharmaceutical Science at Sun Yet-Sen University. Cells were grown in an atmosphere of 5% CO2 and 90% relative humidity at 37°C. They were routinely maintained in Dulbecco’s modified Eagle’s medium (DMEM) containing 4.5 g/l D-glucose, 10% fetal bovine serum, 1% nonessential amino acids, 1% L-glutamine, 1 mM Sodium pyruvate, 100 U/ml penicillin, and 100 g/ml