Influence of controlled-pH and uncontrolled-pH operations on recombinant benzaldehyde lyase production by Escherichia coli

To select the host microorganism having the highest benzaldehyde lyase (BAL) production capacity, pUC 18::bal gene was transferred into four Escherichia coli strains. As the highest enzyme activity was obtained with E. coli K12 (ATCC 10798) carrying pUC18::bal gene, BAL production medium was designed for K 12. Using the designed medium containing 8.0 kg m(-3) glucose, 5.0 kg m(-3) (NH4)(2)HPO4 and the salt solution, the effects of uncontrolled-pH and controlled-pH operations were investigated at uncontrolled-pH pH(UC) 7.2 and controlled-pH values pH(C) 5.0, 6.4, 6.7, 7.0 7.2 and 7.8 in 3.0 dm(3) bioreactor systems with a V-R = 1.65 dm(3) working volume at the air inlet rate of Q(o)/V-R = 0.5 vvm and agitation rate of N= 500 min(-1). The uncontrolled-pH (pHuc 7.2) operation produced the highest cell concentration and BAL activity as C-X = 2.3 kg m(-3) and A = 860 U cm(-3). respectively. Among the controlled-pH operations, the highest cell concentration and enzyme activity were obtained at pH(C) 7.0 operation, respectively, as C-X = 2. 1 kg m(-3) and A = 775 U cm(-3). The accumulation of the metabolic by-product acetic acid and the total organic acid concentrations were the highest at pHc 7.2 and 7.8 operations. On the other hand, there was no significant difference in the acetic acid concentration profiles of pHc 5.0. 6.4, 6.7 and 7.0 operations; however, the highest total organic acid concentration was attained at pHC 5.0 because of the lactic acid excretion, and the lowest total organic acid was obtained at pH(C) 6.7. K(L)a values varied between 0.01 and 0.03 s(-1). To compare the mass transfer and biochemical reaction rates, the maximum possible oxygen utilization rate, possible mass transfer rate, Damkohler number, and effectiveness factor, were also calculated. Damkohler number increased with the cultivation time indicating that mass transfer resistances were becoming more effective than biochemical reaction resistances. The yield and maintenance coefficients as well as the kinetic constants for BAL production process were also reported. (c) 2005 Elsevier Inc. All rights reserved

Reliability and validity of the Turkish version of the ABILHAND questionnaire in rheumatoid arthritis individuals, based on rasch analysis

Objectives: This study aims to assess the reliability and validity of the Turkish version of the ABILHAND questionnaire in individuals with rheumatoid arthritis (RA) [ABILHAND-RA (TR)] using the Rasch analysis. Materials and methods: A total 90 individuals (15 males, 75 females; mean age 51.8±10.9 years; range, 20 to 65 years) diagnosed as RA according to the criteria of the American College of Rheumatology were included. The ABILHAND-RA (TR) was used to determine manual ability, while disease activity was evaluated by the use of Disease Activity Score 28 (DAS28). Jamar hand dynamometer and pinch-meter were used to examine grip and pinch strength of the participants. Nine Hole Peg Test (NHPT) and Duruoz Hand Index (DHI) measured hand disability level. Nottingham Health Profile (NHP) was used to assess quality of life. ABILHAND-RA (TR) results were analyzed using the Rasch analysis method. Results: Item 20 was excluded from the 27-item ABILHAND-RA (TR) as 96% of the individuals rated this item as “easy”. The new set of 18 items (7 subtests and 11 items) were found to sustain item invariance and fit to the Rasch model. Significant relationships were found between ABILHAND-RA (TR) and DAS28, bilateral grip strength, NHPT dominant side results, DHI, and NHP. Conclusion: Turkish version of the ABILHAND-RA was found to be clinically valid, reliable, and sensitive enough to be used in clinical evaluations, rehabilitation interventions, and for progression follow-up in individuals with RA. © 2019 Turkish League Against Rheumatism. All rights reserved