Free-Radical Formation during Storage of Freeze-dried Serratia marcescens

Dimmick, R. L.; Heckly, Robert J.; Hollis, Donald P.

doi:10.1038/192776a0

Cited by 51 publications

(16 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is reported that the presence of antioxidants increased the survival rate of dried bacteria during storage [6,9]. There is a strong similarity between the loss of viability and the increase in freeradical concentration during storage of freeze-dried Serratia marcescens [10]. This hypothesis is supported by others authors, who found that the reactions between carbonyl compounds and cellular components are a major cause of mortality during storage of dried microorganisms [11].…”

Section: Introductionsupporting

confidence: 78%

Survival of Freeze-dried Leuconostoc mesenteroides and Lactobacillus plantarum Related to Their Cellular Fatty Acids Composition during Storage

Coulibaly

Amenan

Lognay

et al. 2008

Appl Biochem Biotechnol

View full text Add to dashboard Cite

Lactic acid bacteria strains Lactobacillus plantarum CWBI-B534 and Leuconostoc ssp. mesenteroïdes (L. mesenteroïdes) Kenya MRog2 were produced in bioreactor, concentrated, with or without cryoprotectants. In general, viable population did not change significantly after freeze-drying ( p>0.05). In most cases, viable population for cells added with cryoprotectants was significantly lower than those without ( p<0.05). Cellular fatty acids (CFAs) from the two strains in this study were analyzed before and after freeze-drying. Six CFAs were identified, namely, palmitic (C 16:0 ), palmitoleic (C 16:1 ), stearic (C 18:0 ), oleic (C 18:1 ), linoleic (C 18:2 ), and linolenic (C 18:3 ) acids were identified. Four of them, C 16:0 , C 16:1 , C 18:0 , and C 18:1 , make up more than 94% or 93% of the fatty acids in L. mesenteroides and L. plantarum, respectively, with another one, namely, C18:3, making a smaller (on average 5-6%, respectively) contribution. The C 18:2 contributed very small percentages (on average≤ 1%) to the total in each strain. C 16:0 had the highest proportion at most points relative to other fatty acids. Moisture content and water activity (a w ) increased significantly during the storage period. It was observed that C 16:1 /C 16:0 , C 18:0 /C 16:0 and C 18:1 /C 16:0 ratios for freeze-dried L. mesenteroides or L. plantarum, with or without cryoprotectants, did not change significantly during the storage period. According to the packaging mode and storage temperatures, C 18:2 /C 16:0 and C 18:3 /C 16:0 ratios for freeze-dried L. mesenteroides and L. plantarum with or without cryoprotectants decreased as the storage time increased. However, a higher C 18:2 /C 16:0 or C 18:3 /C 16:0 ratio for L. mesenteroides and L. plantarum was noted in the freeze-dried powder held at 4°C or under vacuum and in dark than at 20°C or in the presence of oxygen and light.Appl Biochem Biotechnol (2009) 157:70-84 DOI 10.1007/s12010-008-8240-

show abstract

Section: Introductionsupporting

confidence: 78%

Survival of Freeze-dried Leuconostoc mesenteroides and Lactobacillus plantarum Related to Their Cellular Fatty Acids Composition during Storage

Coulibaly

Amenan

Lognay

et al. 2008

Appl Biochem Biotechnol

View full text Add to dashboard Cite

show abstract

“…In that respect, the role of membrane oxidation and oxidation processes in general as well as protein‐sugar reactions (Maillard reactions) should be considered, since membrane deteriorization and compounds toxic to the cell produced during storage may each or in combination be responsible for cell death. Several studies indicates that such reactions contribute to the inactivation of dried bacteria during storage,4, 24–26 but limited information exist on the molecular level of the more specific reactions damaging the bacteria. The detrimental reactions in the bacteria cell and the surrounding matrix contributing to viability loss depend strongly on storage parameters such as the water activity and storage temperature.…”

Section: Discussionmentioning

confidence: 99%

Water activity‐temperature state diagrams of freeze‐dried Lactobacillus acidophilus (La‐5): Influence of physical state on bacterial survival during storage

Kurtmann

Carlsen

Skibsted

et al. 2009

Biotechnology Progress

View full text Add to dashboard Cite

in Wiley InterScience (www.interscience.wiley.com).Water activity-temperature state diagrams for Lactobacillus acidophilus freeze-dried in a sucrose or a lactose matrix were established based on determination of stabilized glass transition temperatures by differential scanning calorimetry during equilibration with respect to water activity at fixed temperatures. The bacteria in the lactose matrix had higher stabilized glass transition temperatures for all a w investigated. The survival of Lactobacillus acidophilus determined as colony forming units for up to 10 weeks of storage at 20 C for (i) a w ¼ 0.11 with both freeze-dried matrices in the glassy state, (ii) a w ¼ 0.23 with the bacteria in the lactose matrix in a glassy state but with the bacteria in sucrose matrix in the nonglassy state, and (iii) a w ¼ 0.43 with both freeze-dried matrices in a nonglassy state showed that the nature of the sugar was more important for storage stability than the physical state of the matrix with the nonreducing sucrose providing better stability than the reducing lactose.

show abstract

“…Indications that exposure of freeze-dried Escherichia coli B to oxygen-induced effects on the flavin-linked pyruvate oxidation similar to airborne E. coli B enable one mechanism of death of airborne E. coli B to be suggested. Contact between oxygen and freezedried E. coli results in the death of the bacteria and the formation of detectable free radicals (Lion, Kirby-Smith & Randolph, 1961 ;Dimmick, Heckley & Hollis, 1961). Most cellular oxidations are mediated by the pyridine nucleotide-flavoprotein-cytochrome c-cytochrome oxidase system, and recently Fox & Tollin (1966) have shown that the mechanism of flavoenzyme action involves radical formation.…”

Section: Discussionmentioning

confidence: 99%

Death Mechanisms in Airborne Escherichia coli

Benbough

1967

Journal of General Microbiology

View full text Add to dashboard Cite

SUMMARYDifferences in survival of Escherichia coli (strain B) sprayed from distilled water into air and into nitrogen as a function of relative humidity (RH) are reported. Two mechanisms which may contribute to death of airborne bacteria are described. In air one death mechanism occurring at low RH is attributed to the action of oxygen causing damage to flavin-linked enzymes as a result of free radical activity. Free radical suppressors are therefore expected to protect airborne E. coli B. Also, electron transport inhibitors like sodium azide, 2,4-dinitrophenol and potassium cyanide are shown to protect E. coli B against lethal effects of oxygen. An analogy is drawn with effects of oxygen on freeze-dried E. coli B. A second death mechanism of E. coli B in air occurs at higher RH's and is considered to result from the effect of aerosolization on RNA synthesis. The activation of RNAse as a possible protection to bacteria in the post-aerosolization medium is discussed. I N T R O D U C T I O NBecause the effect of aerosolization upon bacteria survival is related in a complex manner to relative humidity (RH) of the atmosphere, earlier reports (Dunklin & Puck, 1948;Davis & Bateman, 1960;Bateman, McCaffrey, O'Connor & Monk, 1961) have suggested that bacterial sensitivity increases at certain critical degrees of dehydration. Later reports (Hess, 1965;Cox, 1966) have shown that other factors, e.g. spray fluid, oxygen content of the carrier gas and the collecting fluid, influence the disruption of vital structures and the unbalancing of metabolism. Kinetic studies indicate that : (i) the loss of viability of bacteria is not a simple process; (ii) first-order reactions do not apply; (iii) typically, death rate is initially high and subsequently diminishes progressively.The possibility that overlapping lethal mechanisms exist, makes it extremely difficult to identify bacterial death by a given mechanism in a given set of conditions. One approach to the problem is the use of inert atmospheres to limit the effect of gaseous factors. Another is comparison between results of analogous studies, such as freeze-drying experiments, to derive support for evidence produced in aerosol tests. This paper reports results of such investigations. METHODS Growth of organismsCultures of Escherichia coli (strain B) were grown in 100 ml. of a chemically defined medium for 16 hr at 37", using a shake flask technique. The medium consists of 21-2

show abstract

Free-Radical Formation during Storage of Freeze-dried Serratia marcescens

Cited by 51 publications

References 8 publications

Survival of Freeze-dried Leuconostoc mesenteroides and Lactobacillus plantarum Related to Their Cellular Fatty Acids Composition during Storage

Survival of Freeze-dried Leuconostoc mesenteroides and Lactobacillus plantarum Related to Their Cellular Fatty Acids Composition during Storage

Water activity‐temperature state diagrams of freeze‐dried Lactobacillus acidophilus (La‐5): Influence of physical state on bacterial survival during storage

Death Mechanisms in Airborne Escherichia coli

Contact Info

Product

Resources

About