The flagellar root system in the gamete ofAcetabularia mediterranea

Herth, W.; Heck, Bryan W.; Koop, Hans‐Ulrich

doi:10.1007/bf01287446

Cited by 25 publications

(14 citation statements)

References 15 publications

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“…After washing four times in buffer, they were post-fixed in 2% osmium tetroxide dissolved in the same buffer for 2 h. Further processing for EM was as described by Herth et al (1981).…”

Section: Methodsmentioning

confidence: 99%

Cornual gland of the honeybee drone (Apis mellifera L): structure and secretion

et al. 1996

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Summary — The cornual gland of the drone's endophallus is an epithelial gland, whose cells extend from the tip of the cornual tube, along its lateral parts to the basic hump (dorsal cornua). The gland forms a stripe with a central region of dense and homogeneous secretory cells. To the sides the gland cells become sparse. The secretory cells contain mainly rough endoplasmatic reticulum and numerous mitochondria. The nuclei have several nucleoli and are situated at the apical part. Microvilli border the microfibrillar cuticula into which cell projections often intrude. At the basal membrane the cells are often subtended by a layer of fatty tissue, and oenocytes can also be attached. The secretion in a 3-day-old drone appears either as an orange-coloured layer (deep frozen sections) or as osmiophilic granula (EM) mainly near the lumen of the cornual tube. The cuticula of the cornual tube is untanned and non-sclerotized. Along the lumen of the cornua it is extremely folded and papillated, forming in situ small cavities which contain osmiophilic drops of the secretion, often accumulated in groups. No pores were found, although small granules of secretion occur within the cuticular layers, with the highest concentration near the lumen. During eversion of the cornua the secretion merges on the surface of the cuticula. The cuticula consists of two differently structured layers. Near the lumen of the cornual tube the microfibers extend regular and parallel to the folds; above the gland cells the microfibers are less dense and more irregular.Apis mellifera / drone / sexual organ / endophallus / cornual gland INTRODUCTION

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“…After washing four times in buffer, they were post-fixed in 2% osmium tetroxide dissolved in the same buffer for 2 h. Further processing for EM was as described by Herth et al (1981).…”

Section: Methodsmentioning

confidence: 99%

Cornual gland of the honeybee drone (Apis mellifera L): structure and secretion

et al. 1996

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“…Owing to tbeir positive pbototaxis, tbey migrate towards a small illuminated spot positioned on tbe side of a culture disb and are tberefore cell material tbat can easily be collected in tbe laboratory. Despite tbe ease of availability, Acetabularia gametes bave only rarely been studied in tbe past, Tbeir bilaterally compressed oblong cell sbape suggests tbe presence of a reinforcing internal cytoskeleton, but, due to inadequate cbemical fixation, only tbe bardiest elements of tbe flagellar roots were depicted in early fine structural studies (Crawley, 1966), More labile structures sucb as microtubules were discovered later by Woodcock & Miller (1973) and furtber details of tbe microtubule cytoskeleton and Hagellar root structure were described by Hertb, Heck & Koop (1981), It is only recently tbat tbe entire microtubule cytoskeleton bas been visualized by indirect immunofluorescence (Menzel, Jonitz & Elsner-Menzel, 1992), Tbese and otber studies bave sbown tbat in Acetabularia, as well as in tbe close relative Batophora (Roberts, Stewart & Mattox, 1984), tbe microtubule cytoskeleton is made of two opposite pairs of basal body rootlets witb overall typical ulvopbycean features. Tbese rootlet microtubules run along tbe fiianks of tbe cell to join and overlap at tbe distal cell pole (Fig, 2), the cap rays, the nuclei settle and transform their surroundins cytoplasm into special domains which in turn develop into cysts (9).…”

Section: Gamete Gamete Fusion and Zygotementioning

confidence: 99%

Cell differentiation and the cytoskeleton in Acetabularia

Menzel

1994

New Phytologist

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summary In multicellular organisms, differentiation of individual cells is typically linked to the development of the whole organism. As cells acquire tissue‐specific morphologies and become functionally specialized they lose in turn a number of other functions. A free living, single celled organism, however, maintains all such functions. Compartmentalization and intracellular communication are two basic principles by which expression of specialized features is achieved within a unicell. Both in turn depend on the structure and dynamics of the cytoskeleton. Giant algal unicells lend themselves as experimental models for the study of the cytoskeleton, because the cytoskeletal arrays inside these cells become equally enormous in size. Some of these organisms are large enough to be mistaken for multicellular plants, equipped with holdfast, stem and assimilatory organ. The marine green alga Acetabularia is one of these giant cells, which has already been well known to phycologists and cell biologists for several decades. The current review discusses recent progress in the study of the cytoskeleton in Acetabularia and examines classic concepts of cell morphogenesis from the perspective of cytoskeletal function.

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“…Since then, this connective has been believed to be one of the most reliable features characterizing the Ulvophyceae. Recent investigations on the motile cells of siphonous green algae, Acetabularia (Herth et al 1981) Dictyosphaeria (Hori and Enomoto 1978) and Pseudobryopsis , and Batophora (Roberts, personal communication), and even Enteromorpha (Stuessy et al 1983), however, indicate the possible occurrence of a striated distal connective. On the basis of other ultrastructural features all these members are allied to the Ulvophyceae (Melkonian 1981, 1982, so that the structure of the distal basal body connectives is probably not diagnostic at the class level .…”

Section: Discussionmentioning

confidence: 92%

Flagellar Apparatus of the Quadriflagellated Zoospore of Chaetomorpha spiralis Okamura (Cladophorales, Chlorophyta)

Hirayama¹,

Hori²

1984

Botm

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The flagellar apparatus of the quadriflagellate zoospores of the marine cladophoralean alga, Chaetomorpha spiralis Okamura, was compared with that of other green algae. There is a general similarity, with some important differences, to the Ulvales and siphonous green algae so far studied. Common features are the presence of a cruciate root System (4-2-4-2 type), basal body overlap, the presence of terminal caps and displacement of the upper pair of the basal bodies and four microtubular roots. On the basis of these features, it is concluded that the taxonomic affinities of C. spiralis lie with the Ulvophyceae sensu Stewart and Mattox rather than with the Chlorophyceae sensu Stewart and Mattox.In this alga two pairs of basal bodies He at obviously different levels. Basal bodies of the upper pair are disposed relevant to each other in the 11/5 o'clock direction (counter-clockwise orientation), whereas basal bodies of the Iower pair are in the 1/7 o'clock direction (clockwise orientation). We discuss the terminology of the arrangements of the flagellar apparatus components.Characteristics of the striped fibres which connect the X-membered roots to basal bodies are also discussed and this is given the name "X-membered root associated striped band (XSB)" to distinguish it from the rhizoplast-type System II fibres.

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The flagellar root system in the gamete ofAcetabularia mediterranea

Cited by 25 publications

References 15 publications

Cornual gland of the honeybee drone (Apis mellifera L): structure and secretion

Cornual gland of the honeybee drone (Apis mellifera L): structure and secretion

Cell differentiation and the cytoskeleton in Acetabularia

Flagellar Apparatus of the Quadriflagellated Zoospore of Chaetomorpha spiralis Okamura (Cladophorales, Chlorophyta)

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