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 - 288
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 (9495%)
and after storage (9299%). Fluorescence probes (DPH and TMADPH) 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 TMADPH.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 (9495%)
and after storage (9299%). Fluorescence probes (DPH and TMADPH) 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 TMADPH.Lact. delbrueckii ssp. bulgaricus. Glutamate 5% and aspartate
5% showed similar protection capability during freeze-drying (9495%)
and after storage (9299%). Fluorescence probes (DPH and TMADPH) 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 TMADPH.
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.