[Serratia marcescens B4A chitinase product optimization using Taguchi approach]

Chitinase production by newly isolated Serratia marcescens B4A was optimized following Taguchi's array methods. Twenty-three bacterial isolates were screened from shrimp culture ponds in the South of Iran. A chitinase-producing bacterium was isolated based on it's ability to utilize chitin as the sole carbon source. The isolate designated as B4A, was identified as Serratia marcescens based on its 16S rRNA sequence and key morphological, physiological and biochemical characteristics. The cultivation of Serratia marcescens B4A in the appropriate liquid medium resulted in production of high levels of chitinase. The malt extract and colloidal chitin represented the best nitrogen and carbon sources, respectively. Chitinase production by Serratia marcescens B4A was optimized following the Taguchi orthogonal array [OA] for the design of experiments [DOE]. Statistical experimental design via the Taguchi method was applied to determine the optimal levels of physical parameters and key media components in the medium, such as temperature, pH, NaCl and chitin concentrations. The results of this study showed that temperature of 30§C, pH 7.9, NaCl 0.1% [w/v] and chitin 1% [w/v] are optimal conditions for this protocol

[Comparison of the prevalence and latency of vestibular evoked myogenic potentials in normal participants and symptomatic and asymptomatic Meniere's disease patients]

Vestibular evoked myogenic potentials [VEMP] originate from the saccule and the inferior vestibular nerve. In this study, the prevalence of VEMP and latency of the p13 and n 23 were compared between three groups of individuals, including symptomatic and asymptomatic Meniere's disease cases and normal participants. This study was conducted on 42 cases with the mean age of 40.48 years; thirty were Meniere's disease patients, of which 19 were symptomatic and 11 were asymptomatic; twelve were normal participants. The VEMP were recorded with 500 Hz tone bursts at 120 dBpeSPL. Then the prevalence and latency of the waves were analyzed and compared in the three above mentioned groups. The prevalence of VEMP in symptomatic Meniere's disease patients [52.6%] was significantly less than asymptomatic individuals [90.9%] and also normal subjects [100%] [p<0.05]. There was no significant difference between latencies of the waves in these three groups [p>0.05]. The latency of p13 for symptomatic, asymptomatic and normal participants was 16.41, 15.20 and 14.14 ms, respectively and the latency of n23 for these groups was 20.25, 18.77 and 18.50 ms, respectively. In Meniere's disease, after medical management, the succule probably regains normal function resulting in re-existence of VEMP. It seems that there is no change in the latency of the waves, most likely in re-existence of VEMP. It seems that there is no change in the latency of the waves, most likely due to involvement of the inner ear and intactness of the nerve. VEMP may be a useful test for diagnosis of Meniere's disease and additionally for monitoring the trend of medical management