Cell degeneration during early development of hymenopteran olfactory sensilla

The imaginal pore plates of Hymenoptera apocrita so far examined embody five or six envelope cells respectively. In early developmental stages, however, supernumerary envelope cells have been found. The results are discussed in the context of cell death as a developmental phenomenon.     

Anatomy of the antennal dorsal organ in female of Neodryinus typhlocybae (Hymenoptera: Dryinidae): A peculiar sensory structure possibly involved in perception of host vibration

Neodryinus typhlocybae (Hymenoptera: Dryinidae) is a natural enemy of the planthopper Metcalfa pruinosa, which was introduced from North America into Europe and has become established in various regions as a pest species. Vibrational signals play a crucial role in the communication of M. pruinosa, which appears to be exploited by N. typhlocybae. Scanning and transmission electron microscopy have shown that the antennae of N. typhlocybae females have peculiar and complex sensory structures: deep longitudinal grooves that house long sensilla trichodea, termed here “Antennal Dorsal Organs.” Such structures were not present on male antennae. These sensilla extend for the length of the grooves, without contact with the groove cuticle. Their hair shaft is empty and aporous, and inserted into a specialized socket, underneath which there is a cuticular ampulla‐like chamber. Each sensillum is associated with two sensory neurons: one terminates at the proximal end of the dendritic sheath; the other continues into the sensillum sinus and is enclosed in the dendritic sheath. This second sensory neuron then enters the ampulla‐like chamber through the circular opening, and then terminates with a conspicuous tubular body at the shaft base. The possible involvement of this peculiar structure in the context of host recognition mechanism is discussed. J. Morphol. 277:128–137, 2016. © 2015 Wiley Periodicals, Inc.     

Antennal sensory structures in Nepticulidae (Lepidoptera) and their phylogenetic implications

Antennae of representatives of most genera and subgenera of Nepticulidae have been examined in detail with SEM. Flagellar segments are highly uniform and possess each 1–3 s. trichodea, 1–3 long s. chaetica type I, 12 short s. chaetica type II and 0–2 s. coeloconica of a simpified type without “picket fence”. The dominating structure is a pair of s. vesiculoclada, a unique sensillum type, believed to be a synapomorphy for the Nepticulidae. A pair is present on alt flagellomeres in male antennae but not on all flagellomeres of females in two subgenera of Ectoedemia. Principally each s. vesiculocladum is five-branched, with the branches joined tightly to the flagellar cuticle, but reduction of the branches occurs in several genera, in particular in Ectoedemia. This sensillum can be classified as a single-walled wp sensillum, and thus a chemoreceptor. The s. vesiculocladum is considered to be a homologue of the ascoid sensilla in the Opostegidae. The presence of these special setae is considered as an additional synapomorphy for both families. A review of previous Literature on lepidopteran sensilla is presented and the present data are compared and discussed. In the Nepticulidae the s. vesiculocladum is assumed to be the major pheromone detector in contrast to the s. trichodea of most other Lepidoptera.     

Structure of isolated sensilla and sensory neurons in vitro: Observations on developing silkmoth antennae

Summary By combined enzymatic and mechanical treatment, it was possible to dissociate the sensory epithelium of developing antennae of male Antheraea polyphemus and A. pernyi silkmoths from the stage of separation of the antennal branches up to the early stages of cuticle deposition. Large numbers of entire developing trichoid sensilla were isolated. These are characterized by a large trichogen cell with a long apical, hair-forming process and a large nucleus. A cluster of 2–3 sensory neurons, enclosed by the thecogen cell, is situated in the basal region. The dendrites run past the nucleus of the trichogen cell into the apical process from which they protrude laterally. The nuclei of the tormogen and a 4^th enveloping cell can be distinguished near the base of the prospective hair. After further dissociation, only the neuron clusters remain, still enclosed by their thecogen cell and often attached to the antennal branch nerve via their axons. It is finally possible to disrupt the thecogen cells and the axons, leaving the sensory neurons with inner dendritic segments and axon stumps. The majority of these neurons can be expected to be olfactory.     

Surface charges of the membrane and cell adhesion substances determine the structural integrity of hair bundles from the inner ear of fish

Summary The hairs (stereocilia = stereovilli) of sensory cells from the inner ear of vertebrates are interconnected by several types of connectors, whose role is unknown. They appear to stabilize the hair bundle mechanically, and may be directly involved in mechano-electric transduction. Our transmission electron-microscopical investigation of sensory epithelia from two species of fish (Rutilus rutilus, Scardinius erythrophthalmus, both Leuciscidae) has shown that not only the connectors but also the surface charges of the membrane are important factors for determining the shape of the hair bundle and the spatial interrelation of the stereovilli. A reduction of the ionic strength in the medium leads to an increase in distance between the stereovilli. This may be the result of an extension of the spread of the surface potential of the membrane at low ionic strength. The connectors are not broken by the increase in distance between the stereovilli. They are EDTA (ethylene-diamine-tetra-acetic-acid) resistant as are some cell adhesion molecules such as N-CAM (nerve-cell adhesion molecule) and protein A from Dictyostelium discoideum. The connectors do not prevent polycation-induced fusion of adjacent stereovillar membranes.     

Immunofluorescent localization of collagen types I,III and IV,fibronectin, laminin,and basement membrane proteoglycan in developing mouse skin

Summary The distribution of various extracellular matrix components was studied in frozen sections of embryonic (14–18 days) and early postnatal (birth and 4 days post parturn) dorsal mouse skin using monospecific antibodies and indirect immunofluorescence. Basement membrane zone components — type IV collagen, laminin and heparan sulphate proteoglycan — were found to be uniformly and unchangingly distributed along the dermal-epidermal junction. In contrast, the distribution of interstitial matrix components — types I and III collagen, and fibronectin — was heterogeneous and varied with the stages of hair development. Collagens became sparse and were eventually completely removed from the prospective dermal papilla and from a one-cell-thick sheath of dermal cells around hair buds. They remained absent from the dermal papilla throughout hair organogenesis. Fibronectin was always present around dermal papilla cells and was particularly abundant along the dermal-epidermal junction of hair rudiments, as well as underneath hair buds. In contrast, in interfollicular skin, collagens accumulated in increasing density, while fibronectin became progressively sparser. It thus appears that interstitial collagens and fibronectin are distributed in a manner which is related to hair morphogenesis. In morphogenetically active regions, collagen density is low, while that of fibronectin is high. Conversely, in histologically stabilized zones, collagen is abundant and fibronectin is sparse. This microheterogeneous distribution of interstitial collagens and of fibronectin might thus constitute part of the morphogenetic message that the dermis is known to transmit to the epidermis during the development of skin and of cutaneous appendages.     

Appearance of B and H blood group antigens in the developing cochlear hair cells

Summary The presence of human blood-group antigens was analyzed in the rat cochlea during its postnatal development, using anti-A, anti-B and anti-H antibodies. At no stage was reactivity with anti-A antibody observed. With the anti-H antibody, a strong reactivity was observed from 1 to 9 days after birth within hair cells and some other surface epithelial cells of the cochlear duct. After postnatal day 9, only a faint reactivity persisted in a few non-sensory cells. With the anti-B antibody, only hair cells were selectively labeled. At early stages (postnatal day 1 and 3), the reactivity was intense and observed both around the cell surface and within the supranuclear region of cytoplasm. Later on, the reactivity decreased; it was limited at postnatal day 9 to a reactive spot below the cuticular plate. Results are compared with a preliminary finding describing the first appearance of B and H antigens in the organ of Corti at a prenatal stage, and with data concerning other sensory and neural structures. The appearance and progressive disappearance of B and H antigens on sensory and non-sensory cells can be correlated with significant events in the development of the cochlea. The transient expression of B and H antigens in cochlear sensory cells may correspond to developmental changes in their surface glycoconjugates.     

Hair morphology and systematics ofPhysalis (Solanaceae)

Hair morphology was exammed on developing seedlings and mature plants of ten species from five of seven series inPhysalis. The taxonomic importance of hair development and the distribution of hair types then was evaluated with respect to other comparative data. Two classes of hair types were observed, as found in earlier investigations ofSolanum andRhododendron. The first hair class comprises a sequence from unbranched hairs to dendroid-stelliform hairs. Hairs of this class show considerable variability among taxa in size, presence or absence of glandular tips, and presence and degree of branching, and so were useful in making taxonomic comparisons. The second hair class consists of short hairs, each tipped with a multicellular gland. This second hair class was not useful taxonomically because of its lack of variability in morphology and its often rare occurrence on a plant. The taxa studied exhibit distinctive trichome features which serve to distinguish series and, in some cases together with other data, provided new insight into previously enigmatic species relationships.     

九江地区人头发横断面的研究

本文对九江市汉族463例健康人,4710根头发横断面进行观察和显微测量。分析了本地区人年龄与头发直径的关系、年龄与头发黑色素颗粒分布的关系。结果表明:黑色素颗粒随年龄增长而渐浓密,成年人最丰富,老年人头发黑色素颗粒则渐崩溃稀少;头发各径亦随年龄增长而增大,而老年人头发各径是逐渐减小。此外,本文还同欧、亚、美国各民族人头发资料进行比较。根据头发指数,确定本市人头发形伏为直发形。