Evaluation of structural changes induced by high hydrostatic pressure in Leuconostoc mesenteroides

Date

2004-02-01

Author

Kaletunc, G
Lee, J
Alpas, Hami
Bozoglu, F

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

31
views

0
downloads

Scanning electron microcopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) were used to evaluate structural changes in Leuconostoc mesenteroides cells as a function of high-hydrostatic-pressure treatment. This bacterium usually grows in chains of cells, which were increasingly dechained at elevated pressures. High-pressure treatments at 250 and 500 MPa also caused changes in the external surface and internal structure of cells. Dechaining and blister formation on the surface of cells increased with pressure, as observed in SEM micrographs. TEM studies showed that cytoplasmic components of the cells were affected by high-pressure treatment. DSC studies of whole cells showed increasing denaturation of ribosomes with pressure, in keeping with dense compacted regions in the cytoplasm of pressure-treated cells observed in TEM micrographs. Apparent reduction of intact ribosomes observed in DSC thermograms was related to the reduction in number of viable cells. The results indicate that inactivation of L. mesenteroides cells is mainly due to ribosomal denaturation observed as a reduction of the corresponding peak in DSC thermograms and condensed interior regions of cytoplasm in TEM micrographs.

Subject Keywords

Biotechnology, Food Science, Ecology, Applied Microbiology and Biotechnology

URI

https://hdl.handle.net/11511/45898

Journal

APPLIED AND ENVIRONMENTAL MICROBIOLOGY

DOI

https://doi.org/10.1128/aem.70.2.1116-1122.2004

Collections

Department of Food Engineering, Article

Suggestions

OpenMETU
Core

Design of a core-shell type immuno-magnetic separation system and multiplex PCR for rapid detection of pathogens from food samples Ozalp, V. Cengiz; BAYRAMOĞLU, GÜLAY; ARICA, MEHMET YAKUP; Öktem, Hüseyin Avni (Springer Science and Business Media LLC, 2013-11-01) We report an immuno-magnetic separation system developed by the immobilization of pathogen-specific antibodies on the core-shell magnetic beads. The magnetic beads were grafted with glycidylmethacrylate (GMA) using surface-initiated atom transfer radical polymerization (SI-ATRP). For immuno-magnetic separation (IMS) of target bacterial cells from others, antibodies for Escherichia coli and Salmonella enterica serovar Typhimurium cells were immobilized on the magnetic beads via glutaraldehyde coupling reacti...
Selective oxidation and reduction reactions with cofactor regeneration mediated by galactitol-, lactate-, and formate dehydrogenases immobilized on magnetic nanoparticles Demir, Ayhan Sıtkı; Talpur, Farah N.; Sopaci, S. Betul; Kohring, Gert-W; ÇELİK, AYHAN (Elsevier BV, 2011-04-10) Rapid immobilization with the one-pot purification of galactitol dehydrogenase (GatDH) and formate dehydrogenase (FDH) is achieved by using iminodiacetic acid (IDA) with chelated Co2+ modified magnetic nanoparticles as a carrier. Lactate dehydrogenase (LDH) from recombinant Escherichia coli and FDH commencing Candida methylica were used as an auxiliary enzyme for the regeneration of NADH/NAD(+) with a representative synthesis of (S)-1,2-propanediol and L-tagatose starting from hydroxyacetone and galactitol....
Evaluation of high hydrostatic pressure sensitivity of Staphylococcus aureus and Escherichia coli O157 : H7 by differential scanning calorimetry Alpas, Hami; BOZOGLU, F; KALETUNC, G (Elsevier BV, 2003-11-01) Differential scanning calorimetry (DSC) was used to evaluate the relative high hydrostatic pressure (HHP) resistances of bacterial strains from Staphylococcus aureus and Escherichia coli O157:H7 in vivo. The total apparent enthalpy change and thermal stability were two DSC parameters used to compare bacterial strains of untreated control and pressure-treated bacteria. DSC thermograms indicated that ribosomal denaturation appears to be a major factor in cell death by both thermal and high pressure treatments...
MODEL FOR TRANSIENT MOISTURE PROFILES OF A DRYING APPLE SLAB USING THE DATA OBTAINED WITH MAGNETIC-RESONANCE-IMAGING MCCARTHY, MJ; PEREZ, E; OZILGEN, M (Wiley, 1991-11-01) The use of magnetic resonance imaging (MRI) spectroscopy as a real time probe to noninvasively obtain transient moisture profiles during food dehydration is demonstrated. A laboratory-scale wind tunnel drier was constructed. A 2 x 5 x 5 cm3 apple slab was inserted in the probative zone and one-dimensional drying was effected at quasiisothermal conditions. Spatial resolution of 0.60 mm was obtained. The transient moisture profiles were simulated with a simple mass transfer model. Effective diffusivity of wat...
RT-PCR amplification of a Rhizopus oryzae lactate dehydrogenase gene fragment Hakki, EE; Akkaya, Mahinur (Elsevier BV, 2001-02-01) No amino acid or DNA sequence information in sequence databases was found for a fungal lactate dehydrogenase (LDH) isozyme. Highly conserved regions in the lactate dehydrogenase enzymes of all taxonomies are found to be beta alpha beta nucleotide binding and substrate binding sites, also catalysis/active site. The conserved regions were selected as PCR primer target regions. The degenerate primers were designed according to the codon usage, determined by analyzing a number of different genes of Rhizopus spe...

Citation Formats

G. Kaletunc, J. Lee, H. Alpas, and F. Bozoglu, “Evaluation of structural changes induced by high hydrostatic pressure in Leuconostoc mesenteroides,” APPLIED AND ENVIRONMENTAL MICROBIOLOGY, pp. 1116–1122, 2004, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/45898.