On the origin of variants of the marine bacteriumDeleya aesta134 able to grow at low Na+concentration

Deleya aesta 134 grows optimally at 200 mM Na+in a chemically defined medium but at 10 mM Na+only after an extended lag period which was reduced if the cells that grew were reinoculated into medium of the same low Na+concentration. Cells that eventually grew at low Na+formed colonies on agar containing 17 mM Na+in the agar supernatant (the liquid released when the agar was compacted). Cells of the parent failed to form colonies at this Na+concentration when 102cells were plated. Colonies that formed on low Na+agar differed in appearance from colonies of the parent and three colony types were distinguished. When 106cells of D. aesta grown in liquid medium containing optimum Na+were spread on plates containing 17 mM Na+, a few variant colonies first appeared on day 4 and then increased in numbers over a 20-day period. In nine similar cultures the yield of colonies varied over a 3-log range. Fluctuation tests applied to the numbers arising from the similar cultures after different periods of incubation of the plates showed that the ratio of the variance to the mean was much greater than one initially and then increased with time. A total of seven different variants were isolated. These could be distinguished by the colony type formed, the length of the lag time preceding the first appearance of colonies, and the rate of colony accumulation on low (and in one case, high) Na+plates. The variants retained their distinctive characteristics when replated at low Na+after growth at optimum Na+. Differences in lag time and rate of colony accumulation were related to differences in Na+requirement of the variants and to the presence of other colonies on the plates. The variants appear to arise as the result of random mutations in the growing culture. There was no evidence of adaptive mutation.Key words: Deleya aesta, marine bacteria, variants, Na+response, colony accumulation, adaptive mutation.

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Na+ responses of two marine bacteria that did not appear to require Na+ for growth

Canadian Journal of Microbiology ◽

10.1139/m93-042 ◽

1993 ◽

Vol 39 (3) ◽

pp. 297-303 ◽

Cited By ~ 1

Author(s):

Michelle F. Manuel ◽

Gesine A. Wisse ◽

Robert A. MacLeod

Keyword(s):

Carbon Source ◽

Liquid Medium ◽

Marine Bacteria ◽

Binding Sites ◽

Initial Rate ◽

Nadh Oxidase ◽

Defined Medium ◽

Chemically Defined Medium ◽

Limited Extent ◽

Bacterial Strains

Two Gram-negative heterotrophic marine bacterial strains had been reported not to require Na+ when grown on a chemically defined medium solidifed with purified agar and prepared without added Na+. When these strains were tested in a chemically defined liquid medium they required at least 3 mM Na + for growth. The agar used in the plating medium was found to contribute 3.3 mM Na+. Increasing the concentrations of Na+ in the liquid medium above 3 mM increased the rate and extent of growth of both organisms and decreased the lag periods. Optimal Na+ concentrations for growth varied from 100 to 500 mM depending on the organism and the carbon source in the medium. Na+ was also required for the transport of the carbon source into the cells. For the maximal rate of transport of L-glutamate, one organism required only 10 mM Na +, the other, 50 mM. For acetate and succinate transport the optimal Na+ concentrations varied from 30 to 200 mM depending on the substrate and the organism. When the initial rate of transport of glutamate into one of the organisms was plotted against Na+ concentration the reponse curve was sigmoid and a Hill plot of the data indicated that the transport protein may possess three binding sites for Na+. Evidence was obtained indicating that both organisms possess a Na+-stimulated NADH oxidase. The results indicate that there are marine bacteria that grow to a limited extent at appreciably lower concentrations of Na+ than have been realized previously and for these a much more definitive examination of the requirement for Na+ is necessary.Key words: marine bacteria, Na+ requirement, growth, membrane transport, NADH oxidase.

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Sialic acid levels and lag time of growth in chemically defined medium containing 200 mM phosphate among strains of various serotypes of Streptococcus agalactiae.

Journal of Clinical Microbiology ◽

10.1128/jcm.27.10.2148-2151.1989 ◽

1989 ◽

Vol 27 (10) ◽

pp. 2148-2151 ◽

Cited By ~ 7

Author(s):

Y Nagano ◽

N Nagano ◽

S Takahashi ◽

A Suzuki ◽

Y Okuwaki

Keyword(s):

Sialic Acid ◽

Streptococcus Agalactiae ◽

Lag Time ◽

Defined Medium ◽

Chemically Defined Medium

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Lipopolysaccharide changes and cytoplasmic polyphosphate granule accumulation in Pseudomonas aeruginosa during growth on hexadecane

Canadian Journal of Microbiology ◽

10.1139/m86-049 ◽

1986 ◽

Vol 32 (3) ◽

pp. 248-253 ◽

Cited By ~ 5

Author(s):

Carlos B. Miguez ◽

Terry J. Beveridge ◽

Jordan M. Ingram

Keyword(s):

Pseudomonas Aeruginosa ◽

Sole Carbon Source ◽

Cell Types ◽

Defined Medium ◽

Chemically Defined Medium ◽

Hydrophobicity Index ◽

Active Growth ◽

Thin Sections ◽

X Ray ◽

Lag Period

Pseudomonas aeruginosa ATCC 9027 grew on 0.5% (v/v) hexadecane as a sole carbon source in a chemically defined medium which required the addition of Fe3+ and Ca2+. There was a variable and extended lag period before an active growth rate was attained. Visible light microscopic evidence revealed that the bacteria did not adhere to hexadecane droplets suggesting the absence of a bioemulsifier. When compared with glucose-grown cells, hexadecane-grown cells produced 75% less lipopolysaccharide (on a total protein basis); this lipopolysaccharide contained 30–40% less carbohydrate, yet 50–75% more 2-keto-3-deoxyoctonate. These chemical changes made the cell surface appear more hydrophobic when tested in a biphasic hydrophobicity index system. Electron microscopy of thin sections and freeze etchings revealed hexadecane-grown cells contained granules which were judged to be polyphosphate by energy dispersive X-ray analysis. There was no apparent major morphological envelope alteration within the two cell types.

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Variations in the Metabolism of the Daughter Sporocysts of Microphallus pygmaeus in a Chemically Defined Medium

Journal of Helminthology ◽

10.1017/s0022149x00022161 ◽

1972 ◽

Vol 46 (1) ◽

pp. 107-116 ◽

Cited By ~ 3

Author(s):

R. J. Richards ◽

D. Pascoe ◽

B. L. James

Keyword(s):

Oxygen Uptake ◽

Metabolic Rate ◽

Metabolic Activity ◽

Nutrient Medium ◽

Sea Water ◽

Defined Medium ◽

Chemically Defined Medium ◽

Nutrient Media ◽

Mean Size ◽

The Mean

A comparison is made of the variations in the mean size (length), reduced weight, oxygen uptake, metabolic rate and the number of contained fully formed metacercariae undergoing autolysis, in mature daughter sporocysts of Microphallus pygmaeus, in sea water, artificial sea water and in a chemically defined nutrient medium (modified medium 199). The work indicates that the sporocysts begin to degenerate almost immediately in the non-nutrient media but have a higher metabolic activity and remain healthy for up to 36 days in the nutrient medium.

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Stage-specific requirement of phosphate for development of rat 1-cell embryos in a chemically defined medium

Zygote ◽

10.1017/s0967199400003579 ◽

1997 ◽

Vol 5 (1) ◽

pp. 67-73 ◽

Cited By ~ 18

Author(s):

Kazuchika Miyoshi ◽

Koji Niwa

Keyword(s):

Embryo Development ◽

Defined Medium ◽

Blastocyst Stage ◽

Chemically Defined Medium ◽

Specific Requirement ◽

Blastocyst Formation ◽

The Mean ◽

Almost All

SummaryRat 1-cell embryos, recovered from naturally mated females, were cultured in a chemically defined medium (mR1ECM). When examined after 24, 56, 64 and 80h of culture, embryos developed to the 2-cell (100%), 4-cell (93%), 4-cell to 8-cell (97%) and ≥8-cell (95%) stages, respectively. When 0.4 M phosphate (NaH2PO4) was added to the medium after 0, 24, 56 and 64 h of culture, percentages (0–67%) of embryos that developed to the blastocyst stage after 115h of culture were lower than that (86%) in the medium without phosphate. However, addition of phosphate after 80h of culture accelerated blastocyst formation; a significantly higher percentage (94%) of blastocysts was obtained after 110 h of culture in this medium compared with when phosphate was not added (67%). When phosphate was added to the medium after 64h, almost all (97%) 8-cell embryos developed to the blastocyst stage by 100h of culture but development of 4-cell to 7-cell embryos was inhibited (22–63%). Acceleration of blastocyst formation was caused by addition of phosphate rather than by the exchange of the medium. The stimulatory effect of phosphate on embryo development was observed at concentrations of 0.1–1.2mM. The mean numbers of cells (54.5–60.9 cells) in blastocysts examined after 115 h of culture were increased by the addition of 0.4–1.6mM phosphate at 80 h as compared with blastocysts from cultures without phosphate (46.6 cells).

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Effects by heme, insulin, and serum albumin on heme and protein synthesis in chick embryo liver cells cultured in a chemically defined medium, and a spectrofluorometric assay for porphyrin composition.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)40633-9 ◽

1975 ◽

Vol 250 (24) ◽

pp. 9215-9225 ◽

Cited By ~ 5

Author(s):

S Granick ◽

P Sinclair ◽

S Sassa ◽

G Grieninger

Keyword(s):

Protein Synthesis ◽

Chick Embryo ◽

Serum Albumin ◽

Defined Medium ◽

Liver Cells ◽

Chemically Defined Medium ◽

Embryo Liver ◽

Cells Cultured

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The implications of lag times between nitrate leaching losses and riverine loads for water quality policy

Scientific Reports ◽

10.1038/s41598-021-95302-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

R. W. McDowell ◽

Z. P. Simpson ◽

A. G. Ausseil ◽

Z. Etheridge ◽

R. Law

Keyword(s):

Water Quality ◽

Mean Transit Time ◽

Lag Time ◽

Practice Change ◽

N Leaching ◽

N Losses ◽

Leaching Losses ◽

Nitrate N ◽

The Mean ◽

Lag Times

AbstractUnderstanding the lag time between land management and impacts on riverine nitrate–nitrogen (N) loads is critical to understand when action to mitigate nitrate–N leaching losses from the soil profile may start improving water quality. These lags occur due to leaching of nitrate–N through the subsurface (soil and groundwater). Actions to mitigate nitrate–N losses have been mandated in New Zealand policy to start showing improvements in water quality within five years. We estimated annual rates of nitrate–N leaching and annual nitrate–N loads for 77 river catchments from 1990 to 2018. Lag times between these losses and riverine loads were determined for 34 catchments but could not be determined in other catchments because they exhibited little change in nitrate–N leaching losses or loads. Lag times varied from 1 to 12 years according to factors like catchment size (Strahler stream order and altitude) and slope. For eight catchments where additional isotope and modelling data were available, the mean transit time for surface water at baseflow to pass through the catchment was on average 2.1 years less than, and never greater than, the mean lag time for nitrate–N, inferring our lag time estimates were robust. The median lag time for nitrate–N across the 34 catchments was 4.5 years, meaning that nearly half of these catchments wouldn’t exhibit decreases in nitrate–N because of practice change within the five years outlined in policy.

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