Prostaglandin biosynthesis by fat body from the tobacco hornworm, Manduca sexta

Stanley-Samuelson, David W.; Ogg, C L

doi:10.1016/0965-1748(94)90043-4

Cited by 64 publications

(39 citation statements)

References 34 publications

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“…Stanley-Samuelson and Ogg (1994) detected M. sexta fat body products that co-chromatographed with LOX products. These products were not seen in eicosanoid biosynthesis reactions unless the reactions were conducted in the presence of a COX inhibitor.…”

Section: September 2002mentioning

confidence: 99%

Eicosanoids mediate Manduca sexta cellular response to the fungal pathogen Beauveria bassiana: A role for the lipoxygenase pathway

Lord

Anderson

Stanley

2002

Arch Insect Biochem Physiol

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Many studies have documented the involvement of eicosanoids in insect cellular immune responses to bacteria. The use of the fungal pathogen Beauveria bassiana as a nodulation elicitor, with inhibition of phospholipase A 2 by dexamethasone, extends the principle to fungi. This study also provides the first evidence of involvement of the lipoxygenase (LOX) pathway rather than the cyclooxygenase (COX) pathway in synthesis of the nodulation mediating eicosanoid(s). The LOX product, 5(S)-hydroperoxyeicosa-6E,8Z,11Z,14Z-tetraenoic acid (5-HPETE), substantially reversed nodulation inhibition caused by dexamethasone and the LOX inhibitors, caffeic acid and esculetin. The COX product, prostaglandin H 2 (PGH 2 ), did not reverse the nodulation inhibition by dexamethasone or the COX inhibitor, ibuprofen. None of the inhibitors tested had a significant effect on the phagocytosis of B. bassiana blastospores in vitro. Hemocyte phenoloxidase activity was reduced by dexamethasone, esculetin, and the COX inhibitor, indomethacin. The rescue candidates 5-HPETE and PGH 2 did not reverse the inhibition. Arch.

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Section: September 2002mentioning

confidence: 99%

Eicosanoids mediate Manduca sexta cellular response to the fungal pathogen Beauveria bassiana: A role for the lipoxygenase pathway

Lord

Anderson

Stanley

2002

Arch Insect Biochem Physiol

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“…These experiments followed protocols developed for fat body from M. sexta (Stanley-Samuelson and Ogg, 1994). Briefly, tissues prepared from 15 honey bees were mechanically ground using a 1-ml glass homogenizer.…”

Section: Determining Biosynthesis Of Prostaglandins By Abdominal Prepmentioning

confidence: 99%

“…The 16 000×g supernatants were microsomal-enriched preparations used in all experiments. Protein concentrations in these preparations were determined as described by Stanley-Samuelson and Ogg (1994).…”

Section: Determining Biosynthesis Of Prostaglandins By Abdominal Prepmentioning

confidence: 99%

“…A mixture of appropriate eicosanoid standards was added to each sample, then samples were applied to thinlayer chromatography plates (described above). The plates were developed and fractions observed as described (Stanley-Samuelson and Ogg, 1994). Bands corresponding in R f to selected authentic eicosanoid standards and to free fatty acids were transferred to liquid scintillation vials.…”

Section: Determining Biosynthesis Of Prostaglandins By Abdominal Prepmentioning

confidence: 99%

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Eicosanoids act in nodulation reactions to bacterial infections in newly emerged adult honey bees, Apis mellifera, but not in older foragers

Bedick

Tunaz

Aliza

et al. 2001

Comparative Biochemistry and Physiology Part C: Toxicology &

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Nodulation is the first, and qualitatively predominant, cellular defense reaction to bacterial infections in insects. We tested the hypothesis that eicosanoids also mediate nodulation reactions to bacterial challenge in adults of a social insect, the honey bee, Apis mellifera. Treating newly-emerged experimental bees with the eicosanoid biosynthesis inhibitor, dexamethasone, impaired nodulation reactions to bacterial infections, and the influence of dexamethasone was reversed by treating infected insects with arachidonic acid, an eicosanoid precursor. Several other eicosanoid biosynthesis inhibitors, including the cyclooxygenase inhibitor, indomethacin, and the dual cyclooxygenase/lipoxygenase inhibitor, phenidone, also impaired the ability of experimental honeybees to form nodules in reaction to bacterial challenge. The influence of phenidone on nodulation was expressed in a dose-dependent manner. However, in experiments with older honey bees foragers, similar bacterial challenge did not evoke nodulation reactions. We infer from our results that while eicosanoids mediate cellular immune responses to bacterial infections in newly emerged honey bees, and more broadly, in most insect species, nodulation reactions to bacterial challenge probably do not occur in all phases of insect life cycles.

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“…Tobacco hornworm, M. sexta, eggs were purchased from Carolina Biological Supply (Burlington, North Carolina). The larvae were reared on artificial diet under semi-sterile conditions (Stanley-Samuelson and Ogg, 1994). Second-and third-day fifth instars were used in all experiments.…”

Section: Bacteria and Insectsmentioning

confidence: 99%

An entomopathogenic bacterium, Xenorhabdus nematophila, inhibits hemocytic phospholipase A2 (PLA2) in tobacco hornworms Manduca sexta

Park

Kim

Tunaz

et al. 2004

Journal of Invertebrate Pathology

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The entomopathogenic bacterium, Xenorhabdus nematophila, induces immunodepression in target insects and finally leads to lethal septicemia of the infected hosts. A hypothesis has been raised that the bacteria inhibit eicosanoid-biosynthesis pathway to interrupt immune signaling of the infected hosts. Here, we show direct evidence that X. nematophila inhibits the activity of phospholipase A2 (PLA2), the initial step in the eicosanoid-biosynthesis pathway. Inhibition of PLA2 was dependent on both incubation time with X. nematophila and the bacterial concentration in in vitro PLA2 preparations of Manduca sexta hemocytes. While living bacteria inhibited PLA2 activity, heat-killed X. nematophila rather increased PLA2 activity. X. nematophila secreted PLA2 inhibitor(s), which were detected in the organic, but not aqueous, extract of the bacterial culture medium. The PLA2 inhibitory activity of the organic extract was lost after heat treatment. These results clearly indicate that X. nematophila inhibits PLA2 activity and thereby inhibits eicosanoid biosynthesis, which leads to immunodepression of the infected hosts.

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Prostaglandin biosynthesis by fat body from the tobacco hornworm, Manduca sexta

Cited by 64 publications

References 34 publications

Eicosanoids mediate Manduca sexta cellular response to the fungal pathogen Beauveria bassiana: A role for the lipoxygenase pathway

Eicosanoids mediate Manduca sexta cellular response to the fungal pathogen Beauveria bassiana: A role for the lipoxygenase pathway

Eicosanoids act in nodulation reactions to bacterial infections in newly emerged adult honey bees, Apis mellifera, but not in older foragers

An entomopathogenic bacterium, Xenorhabdus nematophila, inhibits hemocytic phospholipase A2 (PLA2) in tobacco hornworms Manduca sexta

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