Phase contrast and electron microscopy of the mycetocytes and symbiotes of the pea aphid, Acyrthosiphon pisum

McLean, D. L.; Houk, Edward J.

doi:10.1016/0022-1910(73)90071-1

Cited by 60 publications

(37 citation statements)

References 5 publications

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“…1, land b). Since the P symbiont greatly outnumbers the S symbiont (21), this result suggests that the 10-kb fragment is derived from the numerically predominant P symbiont and the 2-kb fragment is derived from the numerically less common S symbiont. The same 10-and 2-kb fragments are observed in the HindIII-digested DNA obtained from the dissected mycetomes.…”

Section: Resultsmentioning

confidence: 95%

“…In this preparation, the intensity of the 10-kb band is less than that of the 2-kb band. This observation is explained by the facts that the P symbiont is osmotically fragile (15,21) and that during the dissection of the mycetome and its transient storage on ice prior to freezing, some P symbiont cells lyse and their DNA is degraded by nucleases. This degradation, which leads to a decrease of the 10-kb band (lane a), is minimized in the procedure in which whole aphids are frozen and ground prior to DNA purification (lane b).…”

Section: Resultsmentioning

confidence: 99%

“…These endosymbionts are housed in specialized cells (mycetocytes) which aggregate into organlike structures (mycetomes) found in the hemocoel of the aphid. The pea aphid contains two endosymbionts designated the primary (P) and secondary (S) symbionts (21). The oval P symbiont is the predominant organism and is located in the mycetocytes.…”

mentioning

confidence: 99%

“…It has been suggested that the symbionts are related to the rickettsias and chlamydias, two groups of obligate intracellular pathogens, or to the mycoplasmas (15,21). It has also been proposed that the endosymbionts constitute an evolutionary stage which culminated in the formation of mitochondria (14,15).…”

mentioning

confidence: 99%

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Pea aphid symbiont relationships established by analysis of 16S rRNAs

1989

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The pea aphid (Acyrthosiphon pisum Harris) harbors two morphologically distinct procaryotic intracellular symbionts. The genes for the 16S rRNA from these symbionts have (4,15). In addition, treatment of the aphid with procaryote-specific antibiotics leads to the decrease or elimination of the symbionts, with concomitant reduction in weight, fecundity, and longevity of the aphid (5). Evidence suggesting that the symbionts may provide the aphid with plant cell wall-degrading enzymes (8, 10), essential nutrients (5), or a protein (symbionin) necessary for nymphal development (17) has been presented elsewhere.Since the endosymbionts have not been cultivated outside the host aphid, speculation as to their identity has been based on their morphology and the moles percent guanineplus-cytosine content of their DNAs (16,18). It has been suggested that the symbionts are related to the rickettsias and chlamydias, two groups of obligate intracellular pathogens, or to the mycoplasmas (15, 21). It has also been proposed that the endosymbionts constitute an evolutionary stage which culminated in the formation of mitochondria (14,15

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Pea aphid symbiont relationships established by analysis of 16S rRNAs

1989

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“…Some aphid species, such as Acyrthosiphon pisum (pea aphid), contain two endosymbionts, the predominant of which is the round or primary (P-) endosymbiont which is found in the mycetocytes (11,18). Smaller numbers of a rod-shaped or secondary (S-) endosymbiont are found within the sheath cells which partially surround the mycetome.…”

mentioning

confidence: 99%

Evidence for the establishment of aphid-eubacterium endosymbiosis in an ancestor of four aphid families

et al. 1991

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Aphids (superfamily Aphidoidea) contain eubacterial endosymbionts localized within specialized cells (mycetocytes). The endosymbionts are essential for the survival of the aphid hosts. Sequence analyses of the 16S rRNAs from endosymbionts of 11 aphid species from seven tribes and four families have indicated that the endosymbionts are monophyletic. Furthermore, phylogenetic relationships within the symbiont clade parallel the relationships of the corresponding aphid hosts. Our findings suggest that this endocytobiotic association was established in a common ancestor of the four aphid families with subsequent diversification into the present species of aphids and their endosymbionts.

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Linoleic acid biosynthesis in the pea aphid, Acyrthosiphon pisum (Harris)

Renobales¹,

Ryan²,

Heisler³

et al. 1986

Arch Insect Biochem Physiol

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The pea aphid Acyrthosiphon pisum (Harris) incorporated [l-14C]acetate into a phospholipid dienoic fatty acid in a time-dependent manner. In 2-h incubations, the incorporation of radioactivity into the 18:2 fraction was minimal, whereas after 45 h 18:2 was the major fatty acid labeled. Ozonolysis of the isolated dienoic fatty acid methyl ester followed by radio-gas-liquid chromatography showed that radioactivity was associated with fragments containing carbons 1-9 and 13-18. These data established the location of the double bonds in the 9,12 positions and indicated that the entire molecule was labeled from [l-14C]acetate. Tetracycline-treated aphids synthesized linoleic acid in the same proportions as untreated controls. Scanning electron microscopy showed that over 50% of the treated insects had greatly reduced numbers of intracellular symbiotes or lacked them or most of the existing symbiotes had an abnormal appearance. Therefore, we conclude that intracellular symbiotes are not involved in the biosynthesis of linoleic acid in the pea aphid.

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Phase contrast and electron microscopy of the mycetocytes and symbiotes of the pea aphid, Acyrthosiphon pisum

Cited by 60 publications

References 5 publications

Pea aphid symbiont relationships established by analysis of 16S rRNAs

Pea aphid symbiont relationships established by analysis of 16S rRNAs

Evidence for the establishment of aphid-eubacterium endosymbiosis in an ancestor of four aphid families

Linoleic acid biosynthesis in the pea aphid, Acyrthosiphon pisum (Harris)

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