Some Aspects of the Fine Structure of the Mycetomes and Mycetomal Microorganisms in Sitophilus (Coleoptera: Curculionidae)

Musgrave, A.; Grinyer, I.; Homan, Rebecca N.

doi:10.1139/m62-096

Cited by 10 publications

(11 citation statements)

References 3 publications

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“…3) (Musgrave & Grinyer 1968) et S. granarius (Musgrave et al 1962). Chez les pucerons, Hinde (1971) filament.…”

Section: Cytologie -Cytochimieunclassified

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Ovogenèse et transmission des bactéries symbiotiques chez le charançonSitophilus oryzaeL. (Coleoptera: Curculionoidea)

Nardon

2006

Annales de la Société entomologique de France (N.S.)

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Ovogenèse et transmission des bactéries symbiotiques chez le charançon Sitophilus oryzae L. (Coleoptera: Curculionoidea)Summary. Oogenesis and transmission of symbiotic bacteria in the weevil Sitophilus oryzae L. (Coleoptera: Dryophthoridae). Among Coleoptera, and particularly in numerous Dryophthoridae, the insects share intracellular symbiosis with hereditary Gram-negative bacteria (or endocytobiotes). Sitophilus oryzae Primary Endosymbiote (SOPE) belongs to the γ3-proteobacteria group. It is a pleomorphic rod shaped (1 to 30 µm ), non-sporulating and non-ciliated bacterium. In the bacteriocyte the bacteria are not included in vacuoles but lie freely in the cytoplasm. SOPE is closely related to Escherichia coli, with 95% homology on the 16S rDNA gene, and also the primary endosymbiotes of Sitophilus zeamais (97,8% identity). In addition to SOPE, several wild strains of S. oryzae harbor a second symbiotic bacterium, that belongs to the B-group of Wolbachia (an α-proteobacterium). They are not considered in this work since studied strains were deprived of Wolbachia. Previous studies have shown that SOPE is transmitted to the offspring strictly through the female. The bacteria are located in ovaries and in the larval bacteriome. The latter organ is at the junction stomodeummidgut, and does not communicate with the gut lumen. It is dissociated at metamorphosis. This work aims to better describe oogenesis in the weevil Sitophilus oryzae and some other Coleoptera. It was performed with various techniques, some of them being original in histology and histochemistry (BMN fixative, RPH and RPMy). Autoradiographic studies were used to precise the nucleic acid (DNA, RNA) and protein metabolism, in the different cell types of the ovary, and in the symbiotic bacteria. In the adult females, the ovarioles are surrounded with a Tunica propria and a double sheath of flat cells, which present a ribonucleo-proteic metabolism. In the apical bacteriome the bacteriocytes are giant polyploid cells. They contain numerous symbiotic bacteria and exhibit a low cellular activity although they do multiply. They also show a lytic activity with myelinic degeneration figures. Between the bacteriocytes small interstitial cells can be seen. These small cells are also visible between the trophocytes in the tropharium. The trophocytes, or nurse cells, are polyploid and form a pseudosyncitium like. They harbor numerous symbiotes and mitochondria. The chromosoma are apparently at the end of pachytene or at diplotene stages. In opposition to most other telotrophic insects, the nutritive cords are poorly developped in S. oryzae. Despite an intense metabolism of RNA and proteins, no transfer of these substances to oocytes was seen. The oogenesis is accomplished in 8 serial steps, with the two first stages occurring in the nymph. The stage 1 includes oogonia and the stage 2 begins at the first step of meiosis and ends at pachytene. SOPE are rarely visible. At the stage 3 oocytes are found among the prefollicular tissue, at the basis of tropharium (3A)...

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“…3) (Musgrave & Grinyer 1968) et S. granarius (Musgrave et al 1962). Chez les pucerons, Hinde (1971) filament.…”

Section: Cytologie -Cytochimieunclassified

“…Chez Sitophilus oryzae, SOPE apparaît toujours libre dans le cytoplasme des cellules qui l'hébergent (Nardon 1971b). Il n'est pas enclavé dans une vacuole comme chez Oryzaephilus surinamensis (Louis 1970) ou de nombreux autres insectes , notamment des Dryophthoridae (Musgrave et al 1962).…”

Section: Les Symbiotesunclassified

Ovogenèse et transmission des bactéries symbiotiques chez le charançonSitophilus oryzaeL. (Coleoptera: Curculionoidea)

Nardon

2006

Annales de la Société entomologique de France (N.S.)

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“…nlansour ( 1935) and Tarsa-in-Curia (1 93 3 ) both claimed chat the symhiotes of Sitophilzcs broke 11p into coccus-like spores. Another interesting phenomenon is that recently reported by Musgrave, Grinyer and Homan (1962). Mycetomal micro-organisms in GG strain weevils often, at certain stages in the insects, present a characteristic appearance of being spirally coiled within a globular vesicle.…”

Section: Mycetomes In Sitophilusmentioning

confidence: 59%

“…Now, having, it is hoped, generated some interest in these unusual organisms or cell inclusions, it seems proper to enquire as to their reality and identity. Their general appearance in stained material and their appearance under the phasecontrast and electron microscopes all indicate that the structures are indeed living organisms (Musgrave, Grinyer and Homan 1962).…”

Section: Mycetomes In Sitophilusmentioning

confidence: 89%

Insect Mycetomes

Musgrave¹

1964

Can Entomol

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After defining the entomological use of the term mycetome a short general account is given of the various supposedly beneficial relationships between insects and internally harboured micro-organisms and the metabolic balance needed. Not all beneficial micro-organisms are harboured in mycetomes or even in mycetocytes, but the present paper is concerned only with insects having mycetomes. It is shown that there is good evidence for accepting the premise that true micro-organisms are found in insect mycetomes and that the micro-organisms supply the insect host with some useful metabolite (s), Special consideration is given to the genus Sitophilus, Here the mycetomal micro-organisms probably supply a useful nutrient that is "essential" only when the diet available to the weevils is inadequate. Whole wheat grain appears to be an adequate diet. Some strains of weevils apparently free of mycetomal micro-organisms are pale in colour, light in weight and particularly susceptible to dietary changes. Weevils reared at temperatures too much above the optimum lose their mycetomal micro-organisms. Although the organisms are pleomorphic there is evidence that their morphology in any one strain of weevil, reared under standard conditions, is constant: and thus it seems the micro-organisms may have taxonomic value in entomology. The possible origin of mycetomes and of the mutualistic associations are discussed and suggestions made about future research.

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“…These particles are pleomorphic, the variants including filaments up to 30 p in length, which are the forms in which Musgrave & Singh (1965) demonstrated deeply staining compact DNA bodies. Although the electron micrograms do not reveal single low-density zones to correspond with this observation, the moderately well localized zones figured in Musgrave, Grinyer & Homan (1962) and Grinyer & Musgrave (1966) fall within the range of nuclear structure of some freeliving bacteria, as illustrated, for example, by Kellenberger, Ryter & SCchaud (1958).…”

Section: Dnamentioning

confidence: 68%

The Blochmann Bodies: Hereditary Intracellular Symbionts of Insects

Lanham

1968

Biological Reviews

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Summary The term ‘Blochmann body’ was originated by Wheeler in 1889 for bacteria‐like particles in the cytoplasm of cockroach eggs. These particles can be traced during embryonic development to definitive somatic cells, the mycetocytes. These and similar particles of other insects have so far not been cultivated in bacteriological media nor injected into host animals to produce either pathological or benign infections. Their structure and composition indicate them to be evolutionary descendants of free‐living micro‐organisms; operationally, they appear to belong to the class of cell particles designated by Lederberg (1952) as plasmids. Genetic studies have shown the Blochmann bodies to be transmitted through the maternal line. Their presence in the egg cytoplasm at some stage in oocyte development is easily demonstrated, but studies by a number of workers have so far yielded a variety of conflicting claims or suggestions as to how the particles get into the germ cells or oocytes. The Blochmann particles of cockroaches, besides existing in the mycetocytes and eggs, occur embedded in a dense tangle of microvilli which are extensions of the plasma membrane of young oocytes. Essentially particle‐free strains of cockroaches can be produced by feeding aureo‐mycin or high levels of urea, or by withholding manganese. The effect is produced only by treating females, and is delayed one generation. In generations following the first (symbiont‐free) generation, the Blochmann symbionts gradually reappear, suggesting that elimination was not absolute. Blochmann bodies in both the mycetocytes and the ovarioles of the cockroach carry out oxidative metabolism, as indicated by their ability to reduce tetrazolium. Glycolysis has not been demonstrated. The generalization that symbionts of the Blochmann type represent an adaptation to compensate for dietary deficiencies is inapplicable, since deficiencies have not been demonstrated for the diets of cockroaches, weevils, or homopterans—the major insect groups in which the symbionts occur. The symbionts of cockroaches and homopterans appear to be involved in the utilization of nitrogenous waste products in synthetic metabolism. In most instances the Blochmann bodies lack the central nucleoid body characteristic of the growing phase of free‐living bacteria, thus resembling the Kappa and Mu particles of Paramecium and the endosymbiont of the protozoan Crithidia oncopelti. Both histochemical tests and electron‐microscope studies indicate a DNA component that is widely dispersed within the particle. Blochmann bodies are without internal cristae. The cockroach symbionts contain muramic acid, a diagnostic feature of the cell wall of bacteria. Response to various nuclear and cytoplasmic reagents is intermediate between those of typical mitochondria and free‐living bacteria. The envelopes of the Blochmann particles are generally thinner than those of free‐living bacteria. The function of plasmids of the Blochmann type may be that they, like the bacteroids of the Rhixobium‐legume symbiosis, ext...

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Some Aspects of the Fine Structure of the Mycetomes and Mycetomal Microorganisms in Sitophilus (Coleoptera: Curculionidae)

Cited by 10 publications

References 3 publications

Ovogenèse et transmission des bactéries symbiotiques chez le charançonSitophilus oryzaeL. (Coleoptera: Curculionoidea)

Ovogenèse et transmission des bactéries symbiotiques chez le charançonSitophilus oryzaeL. (Coleoptera: Curculionoidea)

Insect Mycetomes

The Blochmann Bodies: Hereditary Intracellular Symbionts of Insects

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