CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
artículos
Título:
Effects of protective agents on membrane fluidity of freeze-dried Lactobacillus delbrueckii ssp. bulgaricus
Autor/es:
G.I MARTOS; C.J.MINAHK; G. FONT DE VALDEZ; R. MORERO
Revista:
LETTERS IN APPLIED MICROBIOLOGY
Referencias:
Año: 2007 vol. 45 p. 282 - 282
ISSN:
0266-8254
Resumen:
To evaluate the effect of protective agents upon survival of Lactobacillus delbrueckii ssp. bulgaricus during freeze-drying and storage, and selective amino acids on cell membrane fluidity.Lactobacillus delbrueckii ssp. bulgaricus during freeze-drying and storage, and selective amino acids on cell membrane fluidity.ssp. bulgaricus during freeze-drying and storage, and selective amino acids on cell membrane fluidity. Methods and Results: The protective effect of amino-acids and sugars at different concentrations was studied by determining the viability of lyophilized cells after storage under air at 30C. Survival following freeze-drying was improved by all compounds. During storage, neither proline nor maltose had protective effects on lyophilized Lact. delbrueckii ssp. bulgaricus. Glutamate 5% and aspartate 5% showed similar protection capability during freeze-drying (94–95%) and after storage (92–99%). Fluorescence probes (DPH and TMA–DPH) were used to study the effect of both amino acids on membrane fluidity. Polarization decreased with increasing concentrations of glutamate or aspartate. Lowest values were observed with TMA–DPH.The protective effect of amino-acids and sugars at different concentrations was studied by determining the viability of lyophilized cells after storage under air at 30C. Survival following freeze-drying was improved by all compounds. During storage, neither proline nor maltose had protective effects on lyophilized Lact. delbrueckii ssp. bulgaricus. Glutamate 5% and aspartate 5% showed similar protection capability during freeze-drying (94–95%) and after storage (92–99%). Fluorescence probes (DPH and TMA–DPH) were used to study the effect of both amino acids on membrane fluidity. Polarization decreased with increasing concentrations of glutamate or aspartate. Lowest values were observed with TMA–DPH.Lact. delbrueckii ssp. bulgaricus. Glutamate 5% and aspartate 5% showed similar protection capability during freeze-drying (94–95%) and after storage (92–99%). Fluorescence probes (DPH and TMA–DPH) were used to study the effect of both amino acids on membrane fluidity. Polarization decreased with increasing concentrations of glutamate or aspartate. Lowest values were observed with TMA–DPH. Conclusions: Glutamate 5% and aspartate 5% allowed maintaining high viability rates during freeze-drying and storage of Lact. delbrueckii ssp. bulgaricusGlutamate 5% and aspartate 5% allowed maintaining high viability rates during freeze-drying and storage of Lact. delbrueckii ssp. bulgaricusLact. delbrueckii ssp. bulgaricus because of an increase of the membrane fluidity by inserting in the interfacial region of bacterial plasma membrane. Significance and Impact of the Study: These results show the first evidence of the mechanisms underlying glutamate and aspartate as lyoprotectors.These results show the first evidence of the mechanisms underlying glutamate and aspartate as lyoprotectors.