Figure 43.Composite median dorsoventral view of stylet region of soybean cyst nematode, Heterodera glycines J2. Three of seven amphidial cilia are shown. Dendrite forming the microvillar nerve process is ventral to the nerve bundle (note fig. 62) that gives rise to amphidial and accessory cilia. Cephalic framework includes the base shown here and the hexaradiate cuticular structures anterior to it.
Figure 45. Illustration of an inner labial receptor cilium (ILci) with an electron-opaque central core (EOC). Bar=0.1 µm.
Figure 46. Cross section through cephalic framework (CF) showing canals of inner labial receptors (ILC), outer labial receptors (OLC), cephalic receptors (CRC), and amphid (AC). Canals enclose secretion products and, in some cases, sections of ciliary extensions. EOM, electron-opaque material; IAci, inner accessory receptor cilium; St, stylet; SW, stomatal wall. Bar=1.0 µm.
Figure 47. Cross section of a dense core region of an inner labial receptor cilium. Bar=0.1 µm.
Figure 49. Transverse section through base of cephalic framework. Portions of an inner accessory receptor cilium (IAci) extend from initial lateral position to a subventral cephalic sector. Section also shows transverse orientation of several outer accessory receptor cilia (OAci) extending from a peripheral lateral position to adjacent subventral and subdorsal cephalic sectors. AC, amphidial canal. Bar=1.0 µm.
Figure 51. Section through an inner labial receptor canal (ILC) showing enclosed cilia (ILci) and electron-opaque materials (EOM) that surround the cilia. Mt, microtubules. Bar=0.1 µm.
Figure 53. Longitudinal section through a sensillum showing convoluted (cvM) and related laminar membranes (LM) surrounding basal region of receptor. Membranes evaginate into a support cell. Bar=0.5 µm.
Figure 54. Cross section through basal regions of an inner labial receptor, showing doublets and singlets of microtubules within paired cilia. Bar=0.5 µm.
Figure 55. Section of cilia slightly posteriad to sector in fig. 54, showing a receptor with irregular membrane outline. Doublets and singlets of microtubules of both cilia eventually form basal bodies, which in turn are supported by nerve cell bodies. Bar=0.5 µm.
Figure 56. Cephalic receptors (CR1, CR2, CR3, CR4) having up to eight doublets and four singlet microtubules per cilium. Sections of outer labial receptors OLR1 and OLR2 were made through basal region of cilia, while receptors OLR3 and OLR4 were sectioned anteriad. Inner accessory receptor cilia (IAci) appear circular in outline and lack membrane complexes of electron-opaque deposits that characterize outer accessory receptor cilia. Large number of outer accessory receptor cilia (OAci) in anterior region is attributed to branching of those cilia present in basal region. Sheath cells of various receptor cilia are bordered by dense network of microtubules (MtH) that extend from hypodermal layer between cuticle and somatic musculature to these receptor sites. Hypodermis bordered by these microtubules forms irregular channels (IC) that may have electron-opaque materials (EOM), especially in anterior regions of cephalic framework. AC, amphidial canal; ILR, inner labial receptor. Bar=1.0 um.
Figure 58. Longitudinal section through basal portion of several outer accessory cilia corresponding to area shown in figs. 5961. Micrograph shows doublet microtubules (MtD) within cilia and their continuity with rootletlike (R) formations of dendrite terminals that contain numerous singlet microtubules (MtS) and mitochondria (Mc). One of the dendrites projects two cilia. Membrane junction (MJ) between dendrites restricts accumulation of electron-opaque materials (EOM) anteriad to junction. Bar=1.0 µm.
Figure 60. Transverse section through cilia and supporting dendrites within basal region of an amphid, showing diverse arrangement of microtubule doublets (MtD), ciliary rootlets (R), membrane junctions (MJ) between cilia, and a sheath cell. Tubular (to) or microvillar outgrowths are part of nerve process dendrite. Bar=1.0 µm.
Figure 61. High magnification of a portion of basal region of amphidial canal and outer accessory cilia. Four cilia show clearly defined peripheral doublets of microtubules in each cilium. Eight evenly spaced doublets of microtubules are attached to a fibrillar ring (fr) centripetally. Each doublet also has a fibrillar strand that extends from apposed boundaries of their membranes to cilium membrane. Strand from each doublet traverses the axoplasm to form bifid attachments to membrane of each cilium. Four singlets that occur within central ring are attached to ring opposite alternate microtubule doublets. Bar=0.25 µm.
Figure 63. Nerve process dendrite (NPD) with ventral and posterior orientation within amphidial sheath cell (ASC) and completely surrounded by microvillar and tubular outgrowths or membrane extensions. These tubular outgrowths (to) occur either singly or in groups as they contact the unit membrane of the amphidial sheath cell. Electron-opaque material between tubular outgrowths and supporting cell is part of intermembranous accumulation that occurs through nerve process. Some terminal accumulations appear in electron-opaque vesicles (EOV) or elongated sacs. Bar=1.0 µm.
Figure 64. Pair of cilia (arrows) projects from nerve process dendrite. Cross sections of comparable cilia show that each cilium has a set of eight peripheral doublets of microtubules in basal region. Bar=1.0 µm.
Figure 66. Rootlet (R) supporting the microvillar nerve process of paired cilia of fig. 65. Bar=0.5 µm.
Figure 67. Terminals of some microvilli of nerve process of fig. 65. EOV, electron-opaque vesicles. Bar=0.5 µm.
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