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Effects of lead pollution on Ammonia parkinsoniana (foraminifera): ultrastructural and microanalytical approaches.

Frontalini F, Curzi D, Giordano FM, Bernhard JM, Falcieri E, Coccioni R - Eur J Histochem (2015)

Bottom Line: Foraminifera-bearing sediments were placed in mesocosms that were housed in aquaria each with seawater of a different lead concentration.On the basis of transmission electron microscopy and environmental scanning electron microscopy coupled with energy dispersive spectrometer analyses, it was possible to recognize numerous morphological differences between untreated (i.e., control) and treated (i.e., lead enrichment) specimens.In particular, higher concentrations of this pollutant led to numerical increase of lipid droplets characterized by a more electron-dense core, proliferation of residual bodies, a thickening of the organic lining, mitochondrial degeneration, autophagosome proliferation and the development of inorganic aggregates.  All these cytological modifications might be related to the pollutant-induced stress and some of them such as the thickening of organic lining might suggest a potential mechanism of protection adopted by foraminifera.

View Article: PubMed Central - PubMed

Affiliation: University of Urbino Carlo Bo. fabrizio.frontalini@uniurb.it.

ABSTRACT
The responses of Ammonia parkinsoniana (Foraminifera) exposed to different concentrations of lead (Pb) were evaluated at the cytological level. Foraminifera-bearing sediments were placed in mesocosms that were housed in aquaria each with seawater of a different lead concentration. On the basis of transmission electron microscopy and environmental scanning electron microscopy coupled with energy dispersive spectrometer analyses, it was possible to recognize numerous morphological differences between untreated (i.e., control) and treated (i.e., lead enrichment) specimens. In particular, higher concentrations of this pollutant led to numerical increase of lipid droplets characterized by a more electron-dense core, proliferation of residual bodies, a thickening of the organic lining, mitochondrial degeneration, autophagosome proliferation and the development of inorganic aggregates.  All these cytological modifications might be related to the pollutant-induced stress and some of them such as the thickening of organic lining might suggest a potential mechanism of protection adopted by foraminifera.

No MeSH data available.


Related in: MedlinePlus

The amount of lipid vacuoles (l) appears lower in the control (A) compared to the polluted samples (B). High magnification of lipid droplets in untreated specimens (C) and treated ones (D), which show an electron-dense core and a well-defined membrane. Scale bars: A, B) 1 µm; C, D) 250 nm.
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fig002: The amount of lipid vacuoles (l) appears lower in the control (A) compared to the polluted samples (B). High magnification of lipid droplets in untreated specimens (C) and treated ones (D), which show an electron-dense core and a well-defined membrane. Scale bars: A, B) 1 µm; C, D) 250 nm.

Mentions: On the other hand, numerous morphological differences were observed between control and lead-treated samples. These differences are particularly evident when W8-c and W8-10 ppm are compared. Foraminifera from lead treatments revealed more cytoplasmic degradation in the younger chambers compared to the control group and, at low magnification, the cytoplasm of the Pb-treated foraminifera appeared to display an increased number of lipid droplets (Figure 2 A,B). These bodies were surrounded by a distinct membrane that seemed to be thicker in the Pb-treated group in comparison to the control. In addition, the lipid droplets of the Pb-treated group revealed an electron-dense core that was not, however, visible in the control specimens (Figure 2 C,D). At higher magnification, other ultrastructural differences could be highlighted between Pb-treated and untreated specimens. In particular, while mitochondria of the control group displayed typical distributions and morphology, characterized by a double external membrane and tubular cristae, the Pb-treated specimens showed regular and typical organelles in the older chambers, but in the younger, these appear quite degraded, losing the continuity of double membrane as well as the cristae integrity, the amount of which was reduced (Figure 3 A,B). The thickness of the IOL was variable among the chambers but specimens of the W8-10ppm group displayed a general thickening of the IOL in comparison to W8-c although this structure did not appear morphologically different in the two conditions (Figure 3 C,D). An increased number of residual bodies and membrane-like organelles, tentatively interpreted as putative lipofuscin, were revealed in the W8-10 ppm specimens. Residual bodies of different sizes were observed, delimited by a prominent membrane that enclosed different indigestible materials and degraded organelles (Figure 4A), while putative lipofuscins displayed a variable number of lipid-containing residues that might appear at different state of degradation (Figure 4B). In the Pb-treated conditions, a higher number of organelles interpreted as autophagosomes (Figure 4C) and small electron-dense accumulations (Figure 4D) were detected.


Effects of lead pollution on Ammonia parkinsoniana (foraminifera): ultrastructural and microanalytical approaches.

Frontalini F, Curzi D, Giordano FM, Bernhard JM, Falcieri E, Coccioni R - Eur J Histochem (2015)

The amount of lipid vacuoles (l) appears lower in the control (A) compared to the polluted samples (B). High magnification of lipid droplets in untreated specimens (C) and treated ones (D), which show an electron-dense core and a well-defined membrane. Scale bars: A, B) 1 µm; C, D) 250 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4378215&req=5

fig002: The amount of lipid vacuoles (l) appears lower in the control (A) compared to the polluted samples (B). High magnification of lipid droplets in untreated specimens (C) and treated ones (D), which show an electron-dense core and a well-defined membrane. Scale bars: A, B) 1 µm; C, D) 250 nm.
Mentions: On the other hand, numerous morphological differences were observed between control and lead-treated samples. These differences are particularly evident when W8-c and W8-10 ppm are compared. Foraminifera from lead treatments revealed more cytoplasmic degradation in the younger chambers compared to the control group and, at low magnification, the cytoplasm of the Pb-treated foraminifera appeared to display an increased number of lipid droplets (Figure 2 A,B). These bodies were surrounded by a distinct membrane that seemed to be thicker in the Pb-treated group in comparison to the control. In addition, the lipid droplets of the Pb-treated group revealed an electron-dense core that was not, however, visible in the control specimens (Figure 2 C,D). At higher magnification, other ultrastructural differences could be highlighted between Pb-treated and untreated specimens. In particular, while mitochondria of the control group displayed typical distributions and morphology, characterized by a double external membrane and tubular cristae, the Pb-treated specimens showed regular and typical organelles in the older chambers, but in the younger, these appear quite degraded, losing the continuity of double membrane as well as the cristae integrity, the amount of which was reduced (Figure 3 A,B). The thickness of the IOL was variable among the chambers but specimens of the W8-10ppm group displayed a general thickening of the IOL in comparison to W8-c although this structure did not appear morphologically different in the two conditions (Figure 3 C,D). An increased number of residual bodies and membrane-like organelles, tentatively interpreted as putative lipofuscin, were revealed in the W8-10 ppm specimens. Residual bodies of different sizes were observed, delimited by a prominent membrane that enclosed different indigestible materials and degraded organelles (Figure 4A), while putative lipofuscins displayed a variable number of lipid-containing residues that might appear at different state of degradation (Figure 4B). In the Pb-treated conditions, a higher number of organelles interpreted as autophagosomes (Figure 4C) and small electron-dense accumulations (Figure 4D) were detected.

Bottom Line: Foraminifera-bearing sediments were placed in mesocosms that were housed in aquaria each with seawater of a different lead concentration.On the basis of transmission electron microscopy and environmental scanning electron microscopy coupled with energy dispersive spectrometer analyses, it was possible to recognize numerous morphological differences between untreated (i.e., control) and treated (i.e., lead enrichment) specimens.In particular, higher concentrations of this pollutant led to numerical increase of lipid droplets characterized by a more electron-dense core, proliferation of residual bodies, a thickening of the organic lining, mitochondrial degeneration, autophagosome proliferation and the development of inorganic aggregates.  All these cytological modifications might be related to the pollutant-induced stress and some of them such as the thickening of organic lining might suggest a potential mechanism of protection adopted by foraminifera.

View Article: PubMed Central - PubMed

Affiliation: University of Urbino Carlo Bo. fabrizio.frontalini@uniurb.it.

ABSTRACT
The responses of Ammonia parkinsoniana (Foraminifera) exposed to different concentrations of lead (Pb) were evaluated at the cytological level. Foraminifera-bearing sediments were placed in mesocosms that were housed in aquaria each with seawater of a different lead concentration. On the basis of transmission electron microscopy and environmental scanning electron microscopy coupled with energy dispersive spectrometer analyses, it was possible to recognize numerous morphological differences between untreated (i.e., control) and treated (i.e., lead enrichment) specimens. In particular, higher concentrations of this pollutant led to numerical increase of lipid droplets characterized by a more electron-dense core, proliferation of residual bodies, a thickening of the organic lining, mitochondrial degeneration, autophagosome proliferation and the development of inorganic aggregates.  All these cytological modifications might be related to the pollutant-induced stress and some of them such as the thickening of organic lining might suggest a potential mechanism of protection adopted by foraminifera.

No MeSH data available.


Related in: MedlinePlus