Cell Recognition of Apoptotic Cells

Smith, Christopher A.; McCarthy, Nicola; Williams, Gwyn T.

doi:10.1007/978-1-4757-9534-9_16

Cited by 5 publications

(4 citation statements)

References 156 publications

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“…The Si abundance agrees very well with log (N Si /N tot )= −4.5 ± 0.10 obtained from UV analysis by Smith (1993). Our result for Mn abundance is consistent with the value (log (N Mn /N H )= −4.5 ± 0.05) found by Jomaron et al (1999) for this star.…”

Section: Hd 221507supporting

confidence: 91%

Abundances and search for vertical stratification in the atmospheres of four HgMn stars

Thiam,

LeBlanc,

Khalack

et al. 2010

Preprint

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Using high resolution, high-S/N archival UVES spectra, we have performed a detailed spectroscopic analysis of 4 chemically peculiar HgMn stars (HD 71066, HD 175640, HD 178065 and HD 221507). Using spectrum synthesis, mean photospheric chemical abundances are derived for 22 ions of 16 elements. We find good agreement between our derived abundances and those published previously by other authors. For the 5 elements that present a sufficient number of suitable lines, we have attempted to detect vertical chemical stratification by analyzing the dependence of derived abundance as a function of optical depth. For most elements and most stars we find no evidence of chemical stratification with typical 3σ upper limits of ∆ log N elem /N tot ∼ 0.1 − 0.2 dex per unit optical depth. However, for Mn in the atmosphere of HD 178065 we find convincing evidence of stratification. Modeling of the line profiles using a two-step model for the abundance of Mn yields a local abundance varying approximately linearly by ∼ 0.7 dex through the optical depth range log τ 5000 = −3.6 to -2.8.

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Section: Hd 221507supporting

confidence: 91%

Abundances and search for vertical stratification in the atmospheres of four HgMn stars

Thiam,

LeBlanc,

Khalack

et al. 2010

Preprint

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“…Although infection with ALC136 (sar) did not induce apoptotic DNA laddering, this mutant induced dramatic morphological changes compared to the other mutant strains. Compared to cells infected with RN6390, cells infected with ALC136 appeared larger and with less densely mottled cell membranes, which are characteristics more commonly observed in cells undergoing necrosis (18). These morphological features were not attributed to apoptotic changes but were typical of cells exposed to cytolytic agents.…”

Section: Discussionmentioning

confidence: 84%

Staphylococcus aureus Agr and Sar Global Regulators Influence Internalization and Induction of Apoptosis

et al. 1998

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Staphylococcus aureus was recently shown to be internalized by and to induce apoptosis in a bovine mammary epithelial cell line, suggesting that these processes could be involved in staphylococcal pathogenesis or persistence. To examine the role of virulence factor regulators during internalization, mutantagr and sar strains of S. aureuswere analyzed for their abilities to enter and induce apoptosis in epithelial cells. Like a previously characterized bovine mastitis isolate, the standard laboratory strain, RN6390 (wild type), entered the epithelial cells and subsequently induced apoptosis. In contrast, the mutant strains RN6911 (agr), ALC136 (sar), and ALC135 (agr sar) were internalized by the cultured cells at levels reproducibly greater than that for RN6390 but failed to induce apoptosis. The internalization of S. aureus was affected by growth phase, suggesting a role foragr-regulated surface proteins in this process. Furthermore, the ability to induce apoptosis required metabolically active intracellular bacteria. These data indicate that the ability ofS. aureus to enter mammalian cells and induce apoptosis is dependent on factors regulated by Agr and Sar. Since transcriptional control by these global regulators is mediated by quorum-sensing and environmental factors, staphylococci may have the potential to induce several alternative effects on cells from an intracellular environment. A model for the function of the agr locus in the context of internalization, intracellular persistence, and dissemination is proposed.

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“…DNA fragmentation laddering was observed predominately in samples from growth media containing detached cells (data not shown). This would be expected since it is characteristic of apoptotic cells to be released from the culture substrate into the growth medium (35). Additionally, some S. aureus-infected MAC-T cells were observed to exhibit an intense green positive fluorescence by using the TUNEL method (Fig.…”

Section: S Aureus Invasion Of Mac-t Cellsmentioning

confidence: 87%

Intracellular Staphylococcus aureus Escapes the Endosome and Induces Apoptosis in Epithelial Cells

et al. 1998

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We examined the invasion of an established bovine mammary epithelial cell line (MAC-T) by a Staphylococcus aureusmastitis isolate to study the potential role of intracellular survival in the persistence of staphylococcal infections. S. aureuscells displayed dose-dependent invasion of MAC-T cells and intracellular survival. An electron microscopic examination of infected cells indicated that the bacteria induced internalization via a mechanism involving membrane pseudopod formation and then escaped into the cytoplasm following lysis of the endosomal membrane. Two hours after the internalization of S. aureus, MAC-T cells exhibited detachment from the matrix, rounding, a mottled cell membrane, and vacuolization of the cytoplasm, all of which are indicative of cells undergoing programmed cell death (apoptosis). By 18 h, the majority of the MAC-T cell population exhibited an apoptotic morphology. Other evidence for apoptosis was the generation of MAC-T cell DNA fragments differing in size by increments of approximately 180 bp and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling of the fragmented nuclear DNA of the infected host cells. These results demonstrate that after internalizationS. aureus escapes the endosome and induces apoptosis in nonprofessional phagocytes.

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Cell Recognition of Apoptotic Cells

Cited by 5 publications

References 156 publications

Abundances and search for vertical stratification in the atmospheres of four HgMn stars

Abundances and search for vertical stratification in the atmospheres of four HgMn stars

Staphylococcus aureus Agr and Sar Global Regulators Influence Internalization and Induction of Apoptosis

Intracellular Staphylococcus aureus Escapes the Endosome and Induces Apoptosis in Epithelial Cells

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