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  • 1970-1974  (6)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    A Redescription of Rhyncheta cyclopum Zenker (Ciliatea, Suctorida) (1972)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 19 (1972), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Rhyncheta cyclopum Zenker (Ciliatea, Suctorida) is described from Cyclops albidus and C. viridis occurring in small lakes in Cheshire. The adults have elongated or irregularly spherical bodies which are rounded apically and flattened basally. There is usually a single primary tentacle which is variable in position, length, and activity. Additional tentacles in various stages of growth and resorption may be present, and an account of these processes is given. The body is attached to the host by a short stalk. The barrel-shaped embryos are produced by a rapid or multiple endogenous budding. The presence of the stalk and supernumerary tentacles are described for the first time, and it is considered that these, together with other features, warrant a redescription of this species. The taxonomic relationship of R. cyclopum to other species of Rhyncheta is considered and a probable connection of the tentacle form in this suctorian with its possible food source is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1972.tb03537.x
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  • 2
    Electronic Resource
    Electronic Resource
    The development and structure of the zoospore vesicle in Bulbochaete hiloensis (1970)
    Springer
    Archives of microbiology 72 (1970), S. 223-237 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. Zoospore mother cells in Bulbochaete are shown to be surrounded by a structure interposed between the plasmalemma and the cell wall which is interpreted as the precursor of the vesicle which temporarily surrounds the zoospore on its release. 2. As this vesicle precursor matures it thickens apically to form a ring consisting of a core and two layers. These two layers envelope the young zoospore as its vesicle. Later a space, referred to as the sub-ring, develops within the middle layer of the ring. 3. Histochemical tests indicate that the vesicle precursor and ring are highly proteinaceous with a small carbohydrate component. 4. Dehiscence is apical and thought to be assisted by the apical ring. Upon release of the zoospore, its vesicle is essentially composed of the inner layer of its precursor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00412174
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  • 3
    Electronic Resource
    Electronic Resource
    Reproduction in Bulbochaete hiloensis (Nordst.) Tiffany (1972)
    Springer
    Archives of microbiology 86 (1972), S. 265-280 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The ellipsoid to subspherical zoospore of Bulbochaete hiloensis (Nordst.) Tiffany consists of a green body surmounted by a dome-shaped colourless head, around the base of which is a ring of flagella. 2. The body cytoplasm is characterized by a reticulated chloroplast which contains stacked thylakoids; incipient, developing and mature pyrenoids; and microtubules. The remaining cytoplasm contains active ER-Golgi complexes, coated vesicles, dense bodies, cored bodies, a mitochondrial nest, large central nucleus and lipid-like bodies, adjacent to the large vacuoles. 3. The colourless head, packed with mitochondria, has an extensive ER-Golgi system and a mass of vesicles thought to contain mucopolysaccharides. 4. The flagellar apparatus contains approximately forty regularly-spaced basal bodies situated below a banded fibrous ring. Between the basal bodies are located striated ascending roots, microtubular descending roots and supporting structures. 5. Zoospores are positively phototactic and it is suggested that motility is directed either through differential flagellar activity or by an internal steering mechanism affected by reorientation of the flagellar apparatus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00424984
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  • 4
    Electronic Resource
    Electronic Resource
    Reproduction in Bulbochaete hiloensis (Nordst.) Tiffany (1973)
    Springer
    Archives of microbiology 90 (1973), S. 343-364 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. Sexual reproduction in Bulbochaete hiloensis (Nordst.) Tiffany is mediated by the production of dwarf males and oogonia. 2. Mature dwarf males have a stipe cell and a variable number of antheridia, each divided by a septum separating two spermatozoids. 3. Each spermatozoid consists of a head and body surmounted by a flagellar apparatus with a ring of six to nine flagella. 4. The spermatozoid body is characterized by a large nucleus with chromatin but without an apparent nucleolus, and a highly reduced chloroplast with stroma starch but no pyrenoids. 5. Each spermatozoid is surrounded by a fibrous vesicle and an electron dense layer which are thought to be functional in the sequential release of the spermatozoids from the antheridium. 6. A vegetative photosynthetic cell undergoes division to eventually give rise to an oogonium and primary and secondary suffultory cells. 7. The suffultory cells have highly vacuolate, degenerate cytoplasm with no chloroplast. 8. Within the oogonium, the nucleus becomes located near an extracytoplasmic, fibrogranular mass of mucosubstances laid down in the vicinity of a partial wall discontinuity. These mucosubstances are possibly functional in splitting the wall to form the fertilization pore. 9. The plug progressively disperses as the oogonial cytoplasm rounds off, receding from the cell wall in the apical and basal regions. 10. Following fertilization the oogonial contents refill the enclosing cell wall. The nucleus returns to the centre of the cell and the cytoplasm becomes dominated by numerous closely-packed, lipid-like bodies. Stages in the development of the seven-layered oospore wall are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408929
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  • 5
    Electronic Resource
    Electronic Resource
    Ultrastructural investigations in the stigonemataceae (cyanophyta) (1972)
    Springer
    Archives of microbiology 82 (1972), S. 283-299 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The general cytoplasmic features of Fischerella muscicola, Stigonema hormoides and cells of Stigonema mamillosum found as a phycobiont in the lichen Ephebe lanata are similar to those found in other cyanophyte cells. 2. In all instances the outer surface of the quadrilayered cell wall bears a series of ridges. The membrane-like outermost layer (L IV) also exhibits a number of evaginations thought to represent sites of extrusion of material from the cytoplasm through the wall into the enveloping fibrous mucilage. 3. Cross walls are formed by inward growth of the two inner layers of the lateral walls, the daughter cells subsequently moving apart through the inward intrusion of the two outer wall layers and a bulk of mucilage. 4. The daughter cells remain connected by a persistent central region of the original septum. This septum is penetrated by pores, although these do not pierce the underlying plasma membranes and no direct connection of the protoplasts is achieved. 5. An apical cell of S. hormoides was found to be capped by remnants of a cross wall, presumably by the disruption of a previously distal cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00424933
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural aspects of petal development inCucumis sativus with particular reference to the chromoplasts (1971)
    Springer
    Protoplasma 73 (1971), S. 1-13 
    Details
    ISSN: 1615-6102
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in fine structure in petals ofCucumis have been followed from an early green stage, through maturity, to a senescent dark yellow stage. The most noticable changes occur in the plastids. In chloroplasts of young green petals bundles of tubules appear in the stroma and increase in number as the thylakoids disappear. The entire plastid is eventually filled by groups of tubules orientated in different planes, separated by a few remaining swollen thylakoids. It is proposed that these “chromoplast tubules” represent a reorganization of the thylakoid material. In the mature chromoplast these tubules have become widely separated and randomly orientated, the whole plastid being approximately five times the volume of the chloroplast from which it was derived. Chromoplasts in senescent petals show a number of cytoplasmic invaginations. Other cytoplasmic components show degredative changes throughout petal maturation corresponding to the senescence syndrome found in cucumber leaves and cotyledons. The significance of the observations is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01286407
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