Microbes, as one of the primary producers of the biosphere, play an important role in ecosystems. Exploring the mechanism of adaptation and resistance of microbial population to various environmental factors has come into focus in the fields of modern microbial ecology and molecular ecology. However, facing the increasingly serious problem of acoustic pollution, very few efforts have been put forth into studying the relation of single cell organisms and sound field exposure. Herein, we studied the biological effects of sound exposure on the growth of E. coli K-12 with different acoustic parameters. The effects of sound exposure on the intracellular macromolecular synthesis and cellular morphology of E. coli K-12 were also analyzed and discussed. Experimental results indicated that E. coli K-12 exposed to sound waves owned a higher biomass and a faster specific growth rate compared to the control group. Also, the average length of E. coli K-12 cells increased more than 27.26%. The maximum biomass and maximum specific growth rate of the stimulation group by 8000 Hz, 80dB sound wave was about 1.7 times and 2.5 times that of the control group, respectively. Moreover, it was observed that E. coli K-12 can respond rapidly to sound stress at both the transcriptional and posttranscriptional levels by promoting the synthesis of intracellular RNA and total protein. Some potential mechanisms may be involved in the responses of bacterial cells to sound stress.
The effects of solid-state fermentation with four filamentous fungi (Rhizopus oligosporus, Actinomucor elegans, Neurospora crassa and Rhizopus oryzae) and their combination on the degradation of protein allergens and anti-nutritional factors (ANFs) of tempeh were evaluated. Glycinin, b-conglycinin, trypsin inhibitor and flatulence-causing oligosaccharides were significantly hydrolysed by all assayed strains but the level of reduction of ANFs depended on the strain. ELISA was conducted to evaluate IgE immunoreactivity using sera from soy sensitive individuals. Results revealed that co-fermentation of R. oligosporus and A. elegans resulted in the highest reduction in IgE immunoreactivity for all sera used and showed greatest degradations on a', a, b, acidic subunits (100% hydrolysed) and extensive hydrolysis of flatulence-causing oligosaccharides. Tempeh fermented with R. oligosporus and A. elegans displayed high level of soluble protein and peptide (<10 kD) content. Co-fermentation of R. oligosporus and A. elegans was proved to be effective in producing hypoallergenic tempeh.
Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)The protein was extracted using the method described by Song et al. (2008) with some modifications. The sample was dissolved in 50 mM Tris-HCL (pH 8.2) Immunoreactivity reduction of tempeh L. Huang et al.
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