Electron probe X-ray microanalysis of bacterial DNA

Sigee, David C.; El-Masry, Mohamed H.

doi:10.1016/0165-022x(87)90120-5

Cited by 10 publications

(4 citation statements)

References 13 publications

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“…These correlations reflect results obtained earlier for cells of other prokaryotes including Anabaena (Clay et aI., 1991) and various bacterial cells (Sigee & Hodson, 1993). Such data suggest defined elemental locations in the cell, including the association of K with nucleic acids (Sigee & E1-Masry, 1987) and polyphosphate bodies (Jensen et al, 1982).…”

Section: Elemental Correlations Within Samplessupporting

confidence: 75%

“…This diversity can be used to advantage in the calculation of correlation coefficients, where correlations between elements in microsamples can provide potentially useful information on elemental associations and compartmentalization within cells (Sigee & Hodson, 1993). The occurrence of clear intracellular correlations between elements also implies that these are removed from the surrounding lake water in a corresponding and co-ordinated fashion.…”

Section: Elemental Correlations Within Samplesmentioning

confidence: 99%

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Elemental composition of phytoplankton in a subtropical lake: X-ray microanalytical studies on the dominant algaeSpirulina platensis(Cyanophyta) andCyclotella meneghiniana(Bacillariophyceae)

El-Bestawy

Bellinger

Sigee

1996

European Journal of Phycology

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Studies were carried out on the phytoplankton of a subtropical polluted lake (Lake Maryut, Egypt) over a I year sampling period. The elemental composition of two major algal constituents-Spirulina platensis (Cyanophyta) and Cyclotella meneghiniana (Bacillariophyceae)-was determined from mixed plankton samples using electron-probe X-ray microanalysis. X-ray emission spectra obtained from S. platensis revealed a wide range of detectable elements. Clear positive (e.g. K-P, Na-C1) and negative (e.g. Na-S, P-C1) statistical correlations were interpreted in terms of elemental associations and compartmentation within the cell. C. meneghiniana had a broadly similar range of elements, but differed in the additional presence of A1 and frequent peaks of Fe and Cu. The high concentration of Si reduced the detectability of other elements, causing a general reduction in mass fraction levels. Comparison of correlation coefficients derived from four sets of data revealed a clear pattern of elemental occurrence in the cell. There were two major groupings (involving divalent and monovalent cations) which may relate respectively to the frustule and protoplasmic compartments of the cell. Uptake of metal pollutants and P was investigated by comparison of cellular and environmental levels. Although metal pollution in the lake was high, no significant uptake was detected in S. platensis and only limited uptake (of Fe and Cu) occurred in C. meneghiniana. In this alga, cell loading with Fe and Cu did not relate to concentrations in contemporary water samples, suggesting that metal accumulation may not be in synchrony with environmental changes. Similar considerations apply to P, since neither S. platensis nor C. meneghiniana showed clear or consistent correlations between cellular and environmental concentrations.

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Section: Elemental Correlations Within Samplessupporting

confidence: 75%

Section: Elemental Correlations Within Samplesmentioning

confidence: 99%

Elemental composition of phytoplankton in a subtropical lake: X-ray microanalytical studies on the dominant algaeSpirulina platensis(Cyanophyta) andCyclotella meneghiniana(Bacillariophyceae)

El-Bestawy

Bellinger

Sigee

1996

European Journal of Phycology

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“…factor 2-Mg, P, K). Previous XRMA studies by Sigee and El-Masry (1987) have demonstrated high levels of cations associated with extracted DNA. The lack of positive correlation of Si with any other elements would suggest its occurrence in a separate cell compartment where other elements do not have a major presence.…”

Section: Elemental Correlationsmentioning

confidence: 91%

“…Na-P, Na-K, K-Cl) were not correlated. Distinct patterns of elemental correlation within sets of XRMA data were first noted for bacterial cells Sigee 1989, Sigee andHodson 1993).…”

Section: Elemental Correlationsmentioning

confidence: 97%

ELEMENTAL COMPOSITION, CORRELATIONS, AND RATIOS WITHIN A POPULATION OF STAURASTRUM PLANCTONICUM (ZYGNEMATALES): AN X‐RAY MICROANALYTICAL STUDY¹

Sigee

Holland

1997

Journal of Phycology

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Individual cells of Staurastrum planctonicum (Ted.) within a mixed freshwater phytoplankton sample were analyzed by scanning electron microscope X-ray microanalysis to determine their elemental composition. X-ray emission spectra routinely showed clear peaks of P, S, and Cl, plus monovalent (Nu, K, and d i v a h t (Mg, Ca) cations. Si and Cu were also present in lower quantities. Concentrations of individual ebments (expressed as mmoE kg-' d?y weight) varied widely among cells, with values over the sample population apfn-oximating to a n m a l distribution. Although intracellular anion and cation leuels varied considerably, signif cant correlations occurred between concentrations of monovalent and divabnt cations (mean ratio 1.41, major diffusible anions and cations (mean ratio 1,2), and total h e l s of electropositive and electronegative e h n t s (mean ratio 1.2). The mon~vabnt cations of K and Na occurred at a mean ratio of 1.2 and were not sipifcant& correlated.Concentrations of individual elements (except Si) showed clear positive correlations within the analyses, with 12 highly significant (99% probability) correlations out of 36 possible combinations. Principal factor analysis showed that elemental correlations were determined by two major factors, with two resulting groups of elements-(Na, S, Cl, Ca, Cu) and (Mg, P, 4. Statistical relationships between elements followed a clear correlation pattern, which retained its charactm'stics men when elemental concentrations were expressed per unit P rather than per unit d7y weight. Elemental concentrations were closely similar in m.atching, but not nonmatching, smicells.The statistical pattern of elemental associations noted in Staurastrum parallels that seen in X-ray microanalytical studies of other algae but d@rs in detail. This pattern of statistical associations has biologcal implications in terms of cell compartmentation, characterization of d i f f e n t cell type.s, and cell interactions with their environment.

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A calcium flux at the termination of replication triggers cell devision in Escherichia coli

Norris

1989

Cell Calcium

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Electron probe X-ray microanalysis of bacterial DNA

Cited by 10 publications

References 13 publications

Elemental composition of phytoplankton in a subtropical lake: X-ray microanalytical studies on the dominant algaeSpirulina platensis(Cyanophyta) andCyclotella meneghiniana(Bacillariophyceae)

Elemental composition of phytoplankton in a subtropical lake: X-ray microanalytical studies on the dominant algaeSpirulina platensis(Cyanophyta) andCyclotella meneghiniana(Bacillariophyceae)

ELEMENTAL COMPOSITION, CORRELATIONS, AND RATIOS WITHIN A POPULATION OF STAURASTRUM PLANCTONICUM (ZYGNEMATALES): AN X‐RAY MICROANALYTICAL STUDY¹

A calcium flux at the termination of replication triggers cell devision in Escherichia coli

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Electron probe X-ray microanalysis of bacterial DNA

Cited by 10 publications

References 13 publications

Elemental composition of phytoplankton in a subtropical lake: X-ray microanalytical studies on the dominant algaeSpirulina platensis(Cyanophyta) andCyclotella meneghiniana(Bacillariophyceae)

Elemental composition of phytoplankton in a subtropical lake: X-ray microanalytical studies on the dominant algaeSpirulina platensis(Cyanophyta) andCyclotella meneghiniana(Bacillariophyceae)

ELEMENTAL COMPOSITION, CORRELATIONS, AND RATIOS WITHIN A POPULATION OF STAURASTRUM PLANCTONICUM (ZYGNEMATALES): AN X‐RAY MICROANALYTICAL STUDY1

A calcium flux at the termination of replication triggers cell devision in Escherichia coli

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ELEMENTAL COMPOSITION, CORRELATIONS, AND RATIOS WITHIN A POPULATION OF STAURASTRUM PLANCTONICUM (ZYGNEMATALES): AN X‐RAY MICROANALYTICAL STUDY¹