agar and potassium-phosphate

Topics: Agar; Animals; Culture Media; Iraq; Penicillium; Phosphates; Potassium Compounds

The present study was aimed at modifying the original formulation of Commercial Eugon agar (CEA) to develop a new H. pylori growth medium. Initial studies were carried out to determine the number of H. pylori colonies recovered on in-house H. pylori agar (IHPA), IHPA without L-cysteine and sodium sulfite (IHPA-NC), IHPA without L-cysteine (IHPA-C), IHPA without sodium sulfite (IHPA-N) and CEA as the control. Significant differences (P < 0.001) in the number of colonies recovered were observed between IHPA-N, IHPA-NC and IHPA-C. Incorporation of sodium sulfite decreased the number of colonies recovered, indicating that sodium sulfite was inhibitory to H. pylori growth. Removal of L-cysteine reduced the number of colonies recovered, suggesting that L-cysteine is necessary for the growth of H. pylori. In the subsequent study, incorporation of K(2)HPO(4) further increased the number of colonies recovered compared with IHPA-N (P < 0.001), and 0.25% (w/v) of K(2)HPO(4) yielded the highest numbers of colonies (P < or = 0.04). Finally, thirty other H. pylori clinical isolates were evaluated for their growth in the IHPAP-N, a new medium consisting of 1.5% (w/v) pepticase, 0.5% (w/v) peptone, 0.4% (w/v) sodium chloride, 0.03% (w/v) L-cysteine, 0.55% (w/v) dextrose, 0.25% (w/v) K(2)HPO(4) and 1.5% (w/v) agar. The number of colonies recovered in IHPAP-N was significantly (P < 0.005) higher than that of CEA. IHPAP-N with 0.25% K(2)HPO(4) and without sodium sulfite were adequate solid media for the growth of H. pylori.

Topics: Agar; Bacteriological Techniques; Colony Count, Microbial; Culture Media; Cysteine; Glucose; Helicobacter pylori; Peptones; Phosphates; Potassium Compounds; Sodium Chloride; Sulfites

The phenotypic difference between virulent and avirulent Legionella pneumophila with regard to growth on supplemented Mueller-Hinton (SMH) agar was investigated. Defined populations of virulent and avirulent L. pneumophila were inoculated onto hybrid growth media containing the combination of SMH agar components with potassium phosphate-buffered charcoal-yeast extract agar. The casein acid hydrolysate component of SMH agar was found to be inhibitory to the growth of virulent but not avirulent cells. The selectively inhibitory component of the casein acid hydrolysate was identified as NaCl.

Topics: Agar; Caseins; Charcoal; Culture Media; Growth Inhibitors; Legionella; Phosphates; Potassium; Potassium Compounds; Protein Hydrolysates; Sodium Chloride; Virulence

Single-energy and dual-energy quantitative computed tomography (CT) techniques were used to analyze test solutions that contained agar, K2HPO4, and isopropanol, which stimulated collagen, mineral, and fat, respectively. The impact of the use of peripheral and anthropomorphic (central) calibration phantoms was also studied. A 10% change in fat content was found to cause errors in the estimated bone mineral content of -10 mg/mL, -14 mg/mL, and -1 mg/mL for single-energy CT at 80 kVp, single-energy CT at 140 kVp, and dual-energy CT, respectively. In the K2HPO4 solutions, the addition of 50 mg/mL agar increased the estimated bone mineral content by 20-33 mg/mL for single-energy CT, and by 12-17 mg/mL for dual-energy CT. The best estimates were obtained with central calibration and dual-energy CT, but the estimates were still 14%-24% greater than the true values. Calibration samples that more accurately simulate actual spongiosa may reduce this source of error. Caution should be exercised in the use of quantitative CT under conditions in which either the bone marrow or collagen content is altered by disease or therapy.

Topics: 1-Propanol; Agar; Bone and Bones; Calibration; Collagen; Humans; Minerals; Phosphates; Potassium; Potassium Compounds; Radiographic Image Enhancement; Solutions; Tomography, X-Ray Computed