Fine structure of the dendritic junction body region of the antennal sensory cone in a larval elaterid (Coleoptera)

1971 ◽  
Vol 49 (6) ◽  
pp. 817-821 ◽  
Author(s):  
David A. Scott ◽  
R. Y. Zacharuk
Keyword(s):  
Fine Structure ◽  
Basal Body ◽  
Sense Organ ◽  
Body Region ◽  
Ultrastructural Evidence ◽  
Primary Function ◽  
Secretory Products

The component ciliary collar, basal body, ciliary rootlets, trichogen–dendrite secretory junctions and secretory inclusions of the junction body region of dendrites in the wireworm antennal sensory cone are described. The primary function ascribed to the junction body region, based on the ultrastructural evidence presented, is one of secretion. The hypothesis that the secretory products produced in the junction body region are transported to the dendritic terminations in the sense organ is discussed and supported.

The role of the monopteros gene in organising the basal body region of the Arabidopsis embryo

Development ◽  
1993 ◽  
Vol 118 (2) ◽  
pp. 575-587 ◽  
Author(s):  
T. Berleth ◽  
G. Jurgens
Keyword(s):  
Tissue Culture ◽  
Pattern Formation ◽  
Basal Body ◽  
Root Formation ◽  
Root Meristem ◽  
Body Region ◽  
Phenotypic Trait ◽  
Embryo Cells ◽  
Stage Embryo

The monopteros (mp) gene contributes to apical-basal pattern formation in the Arabidopsis embryo. mp mutant seedlings lack basal body structures such as hypocotyl, radicle and root meristem, and this pattern deletion has been traced back to alterations in the octant-stage embryo. Cells of the embryo proper and the uppermost cell of the suspensor fail to establish division patterns that would normally generate the basal body structures. The resulting absence of a morphological axis seems to be responsible for another phenotypic trait of mp seedlings, variable positioning of cotyledons. This relationship is suggested by weak mp seedling phenotypes in which the presence of a short hypocotyl is correlated with normal arrangement of cotyledons. Root formation has been induced in mp seedlings grown in tissue culture. This result supports the notion that the mp gene is required for organising the basal body region, rather than for making the root, in the developing embryo.

The Function and Fine Structure of the Cephalic Airflow Receptor in Schistocerca Gregaria

1966 ◽  
Vol 1 (4) ◽  
pp. 463-470
Author(s):  
D. M. GUTHRIE
Keyword(s):  
Fine Structure ◽  
Cell Body ◽  
Schistocerca Gregaria ◽  
Tube Wall ◽  
Sense Organ ◽  
Hair Shaft ◽  
Sensory Axons ◽  
Steady Rate ◽  
Neuron Cell Body ◽  
Tormogen Cell

Electron micrographs of parts of the sense organ showed that the dendritic axis consisted of a large and a small envelope containing microtubules as their main inclusion. The envelopes are supported by a thick-walled tube believed to be part of the Ist-tier sheath cells. The small envelope is segregated from the large envelope near its apex by a fold of the tube wall. The packing of the neurotubular array within the small envelope is both more dense and more regular than within the large envelope. The tube is separated by an extracellular space from the trichogen-tormogen cell. Sections through the apex of the dendrite reveal a homogeneous cap unlikely to be part of a structure continued into the upper region of the hair shaft. No ciliary structures were visible within the dendrite, whose microtubules pass into the neuron cell body proximally. Sections through the neuron cell body reveal branched mitochondria, and numerous microtubules. Rates of discharge in sensory axons from these hair organs produced by deflexion of the hair shaft were found to be within the range 300-100 impulses/sec. There is an initial phase of rapid adaptation which gives place to a steady rate. It is suggested that the fine structure of the receptor may indicate mechano-electrical transduction at a more proximal level than is believed to be the case in some other types of receptor. The diaphragms that support the hair shaft laterally can be seen to be composed of fine cuticular strands.

Comparative study of axopodial microtubule patterns and possible mechanisms of pattern control in the centrohelidian heliozoa Acanthocystis, Raphidiophrys and Heterophrys

1977 ◽  
Vol 25 (1) ◽  
pp. 205-232
Author(s):  
C.F. Bardele
Keyword(s):  
Fine Structure ◽  
Conformational Changes ◽  
Basal Body ◽  
Basic Unit ◽  
Lateral Growth ◽  
Secondary Nucleation ◽  
Body Formation ◽  
Pattern Control ◽  
Nucleation Sites ◽  
Equilateral Triangles

The axopodial microtubule pattern of 9 centrohelidians belonging to the genera Acanthocystis, Raphidiophrys and Heterophrys, as well as the fine structure of their microtubule organizing centre, the centroplast, was studied to determine the rules which govern their patterns. Microtubules capable of binding a xamimum of 4 linkers are arranged in regularly distorted hexagons and equilateral triangles. The number of microtubules present in each axoneme ranges from some 140 in Acanthocystis turfacea to as few as 6 in Heterophrys marina (Stock I). In the later species each axoneme contains a single hexagon of microtubules only. In other Heterophrys species, the central hexagon is surrounded by closely packed microtubules or by microtubules arranged in pentagons; only the central hexagon is anchored in the centroplast shell, whereas additional microtubules seem to originate from secondary nucleation sites somewhat distal to the centroplast. It is argued that the distortion of the basic unit hexagon (with alternate angles close to 134 degrees and 106 degrees) indicates that the microtubules are composed of 13 protofilaments. While in the larger Acanthocystis and Raphidiophrys species, the pattern may result from self-linkage, the arrays found in the Heterophrys species seem to favour a template-determined linkage. To explain the formation of the central hexagon in Heterophrys and balanced lateral growth in the larger microtubule arrays, a ‘linker-nucleation hypothesis’ is proposed. The assumption is made that graded conformational changes in the microtubule subunits not only specify the position where the next linker will bind, but that this linker, through linkage, becomes able to induce secondary microtubule nucleation, which will result in balanced lateral growth of the array. The application of this hypothesis to other microtubule systems, e.g. basal body formation, is discussed.

The fine morphology of the osphradial sense organs of the mollusca. III. Placophora and bivalvia

1987 ◽  
Vol 315 (1169) ◽  
pp. 37-61 ◽  
Keyword(s):  
Fine Structure ◽  
Sense Organ ◽  
Mantle Cavity ◽  
Sense Organs ◽  
Physiological Evidence ◽  
Anal Papillae ◽  
Fine Morphology

The fine morphology of the osphradia of six placophorans and eight bivalves, representing all major subgroups of both classes, is described. In addition the branchial and lateral sense organs of Lepidopleurus cajetanus (Placophora) have been investigated ultrastrucurally. Whereas osphradial fine structure is very uniform within the Bivalvia there are differences between Ischnochitonina and Acanthochitonina, supporting the separation of both groups. Major differences in the conditions of the mantle cavity divide Recent Placophora into the orders Lepidopleurida and Chitonida. The homology of the molluscan osphradium throughout the phylum is discussed in detail. It is concluded that the terminal sense organ (Caudofoveata, Solenogastres), the adanal sensory stripes (Placophora—Chitonida), the interbranchial and post-anal papillae of Nautilus (Cephalopoda), and the organ of Lacaze (Gastropoda-Basommatophora) are homologous with the organs of Spengel (Prosobranchia, Opisthobranchia, Bivalvia), all to be called osphradial sense organs (or osphradia). After discussion it is concluded that the osphradium is a chemoreceptor and not a mechanoreceptor as suggested by many authors. This is shown by the physiological evidence so far reported but mainly by the existence of paddle cilia in the osphradial epithelia throughout the Mollusca, which are typical of molluscan chemoreceptors. It is suggested that the osphradium is primarily used in sexual biology (coordination of spawning, search for a mate), a role altered within the Gastropoda (search for food, osmoreceptor, p O2 -receptor).

Fine structure of granulated cells in the posterior cardinal and renal veins of Amia calva L.

1976 ◽  
Vol 54 (6) ◽  
pp. 843-851 ◽  
Author(s):  
John H. Youson
Keyword(s):  
Fine Structure ◽  
Secretory Granules ◽  
Immediate Release ◽  
Nerve Terminals ◽  
Renal Veins ◽  
Subendothelial Space ◽  
Secretory Products ◽  
Amia Calva ◽  
Relationship Of ◽  
The Relationship

Granulated cells located in the walls of the posterior cardinal and renal veins in the holostean fish Amia calva resemble cells of the adrenal medulla of higher vertebrates. The cells all contain similar electron-dense secretory granules, apparently originating from the Golgi apparatus, and are innervated by nerve terminals. These features suggest that the cells are involved in the production and release of catecholamines. The relationship of the cells to the endothelium of the large veins also suggests that the secretory products of the cells reach the circulation by traversing a complex subendothelial space and passing through the fenestrae of the endothelium. This appears to be an efficient means for the immediate release and distribution of catecholamines in this species of fish.

Some Aspects of the Cytology of Polycelis nigra

1961 ◽  
Vol s3-102 (59) ◽  
pp. 295-317
Author(s):  
R. J. SKAER
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Muscle Fibre ◽  
Cell Body ◽  
Basal Body ◽  
Sense Organs ◽  
Gland Cells ◽  
Secretion Granules ◽  
Undifferentiated Cells

The triclad, Polycelis nigra, has been found to be fully cellular. Gland-cells, undifferentiated cells, and the cell-bodies of muscle-cells, make up the parenchyma. The fine structure of the component cells of the parenchyma, nervous, and excretory systems, testis, pharynx, and epidermis is described. Acidophil secretion granules, produced by certain parenchymatous gland-cells, have a characteristic, doubly-banded ultrastructure which is not invariably associated with the property of adhesiveness. The parenchymatous cell-body of the muscles is often up to 10 µ. from the musclefibre, to which it is joined by tenuous cytoplasmic connexions. The muscle-fibre itself consists of coarse and fine sets of hexagonally arranged myofilaments, but is unhanded. The basement membrane of the epidermis is composed of fine, banded fibrils, apparently randomly arranged in the plane of the membrane. Permeating the epidermis at a level just above the basement membrane is a system of extracellular spaces, which may have a hydrostatic function and assist in the extrusion of secretion granules. Epidermal sense organs, whose fine structure resembles the basal body of the cilia, are considered to have a functionally significant distribution on the surface of the animal. The rhabdites have been shown to develop in special cells of the parenchyma. Such rhabdite-forming cells, together with their contained rhabdites, have been found apparently passing through the basement membrane of the epidermis. As all the epidermal epithelial cells contain rhabdites, it is suggested that the epidermis as a whole is renewed by centrifugal migration of rhabdite-forming cells. The rhabdites themselves appear to consist of arginine and some tyrosine, together with a purine, probably adenine. They may be an excretory product.

scholarly journals A NIMA-related kinase, CNK4, regulates ciliary stability and length

2016 ◽  
Vol 27 (5) ◽  
pp. 838-847 ◽  
Author(s):  
Dan Meng ◽  
Junmin Pan
Keyword(s):  
Electron Microscopy ◽  
Basal Body ◽  
Microtubule Dynamics ◽  
Body Region ◽  
Null Mutant ◽  
Genetic Studies ◽  
Underlying Mechanisms ◽  
Bulge Formation

NIMA-related kinases (Nrks or Neks) have emerged as key regulators of ciliogenesis. In human, mutations in Nek1 and Nek8 cause cilia-related disorders. The ciliary functions of Nrks are mostly revealed by genetic studies; however, the underlying mechanisms are not well understood. Here we show that a Chlamydomonas Nrk, CNK4, regulates ciliary stability and length. CNK4 is localized to the basal body region and the flagella. The cnk4-null mutant exhibited long flagella, with formation of flagellar bulges. The flagella gradually became curled at the bulge formation site, leading to flagellar loss. Electron microscopy shows that the curled flagella involved curling and degeneration of axonemal microtubules. cnk4 mutation resulted in flagellar increases of IFT trains, as well as its accumulation at the flagellar bulges. IFT speeds were not affected, however, IFT trains frequently stalled, leading to reduced IFT frequencies. These data are consistent with a model in which CNK4 regulates microtubule dynamics and IFT to control flagellar stability and length.

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