Labyrinthine Wall Research Articles

Oil and mucilage idioblasts co-occur in the vegetative organs of Ocotea pulchella (Lauraceae): comparative development, ultrastructure and secretions.

This study compares oil and mucilage idioblasts occurring together in the vegetative organs of Ocotea pulchella, a Lauraceae species. Our focus is specifically on the ontogeny and developmental cytology of these secretory cells. Both types of idioblasts originate from solitary cells located in the fundamental meristem, underlying the protodermis. The growth of both types of idioblasts is asynchronous, with the oil idioblasts developing first, but their initiation is restricted to the early stages of organ development. Mucilaginous idioblasts occur exclusively in the palisade parenchyma, while oil idioblasts are scattered throughout the mesophyll, midrib, and petiole of the leaves. The lamellar secretion of mucilage idioblasts is mostly made up of polysaccharides, while the secretion of oil idioblasts is made up of terpenes and lipids. Cupule occurred only in the oil idioblasts, while suberized layers occurred in both types of cells. We found that immature oil idioblasts that are close to each other fuse; mature mucilage idioblasts have labyrinthine walls arranged in a reticulate pattern; the cells close to the oil idioblasts have a pectin protective layer; and the oil idioblasts have a sheath of phenolic cells. In contrast to previous reports, the two types of secretory idioblasts were recognized during the early stages of their development. The results emphasize the importance of combining optical and electron microscopy methods to observe the ontogenetic, histochemical and ultrastructural changes that occur during the development of the secretory idioblasts. This can help us understand how secreting cells store their secretions and how their walls become specialized.

FEATURES OF THE STRUCTURE OF THE LABYRINTH WALL OF THE TYMPANIC CAVITY IN THE THIRD TRIMESTER OF PREGNANCY

Acute otitis media is one of the most common diagnoses among young children, and prematurity is the most common risk factor for its occurrence. The immaturity of the organs and systems of these children often lead to the development of pathological symptom complexes, including from the organ of hearing, which may necessitate surgical intervention. Modern microsurgical technologies signifi cantly increase the quality of operations and reduce the risk of possible complications. The surgeon’s work on these structures requires accurate knowledge of the anatomical and topographic features of the structure of the temporal bone, including in prematurely born children. The syntopy and structure of the labyrinth wall of the tympanic cavity were studied in 35 human fetuses of the seventh to tenth months of intrauterine development and 11 newborn cadavers. It has been established that the dimensions of the structures of the labyrinthine wall of the tympanic cavity in prematurely born children do not have defi nitive dimensions and their location diff ers from that in those born at term. In prematurely born children, the bone wall of the facial nerve canal is absent, in those born on time it is partially present in 18.18% of cases, the angle of passage of the facial nerve canal decreases from 33° in fetuses of the seventh month of intrauterine development to 25° in newborns. The identifi ed features are important in improving technologies and the adequacy of surgical treatment in prematurely born children.

Unraveling the secretion mechanism of the curious nectaries in Gentianaceae.

Unusual nectaries were anatomically described as being usual traits for Gentianaceae. They are small, avascularized, and formed by 3 to 5 rosette cells with labyrinthine walls around one central cell. Such as nectaries have been reported for stems, petals, and sepals of different species of the family, however, there is no information on the mechanisms involved with the synthesis and release of secretion. Thus, this work aimed to unravel the mechanism of secretion and exudation of nectar for these curious nectaries using Calolisianthus speciosus as a model. Samples were processed according to standard methods for light and electron microscopy. Leaf and sepal nectaries were described, as were those of the apex of petals where ants were observed patrolling a darkened region. The enzymatic method was used for the detection of sugars, proteins, and amino acids in leaf and sepal exudates. The nectaries of petals of C. speciosus are similar to those of its leaves, sepals, and stem, although their activities are asynchronous. Polysaccharides were detected on the labyrinthine walls of rosette cells and protein in the opposite region of the cytoplasm. Labyrinthine walls increase the contact surface between rosette cells and the central cell, allowing for the transfer of secretion. After accumulation, the secretion is released to the subcuticular space of the central cell through disruption of the cuticle. The secretion and exudation of nectar were elucidated and involve distinct organelles.

Topographic Anatomy of the Medial Labyrinthine Wall: Implications for the Transcanal Endoscopic Approach to the Internal Auditory Canal.

To characterize transcanal endoscopic landmarks of the medial labyrinthine wall and correlate these with anatomical features of the fundus of the internal auditory canal (IAC). The transcanal transpromontorial approach (TTA) enables minimally invasive access to the IAC. The establishment of a landmark-based dissection technique for the approach is crucial to avoid injury to the facial nerve. Twenty temporal bones were dissected endoscopically through the TTA. Furthermore, high-resolution computed tomography (CT) scans from ten adult normal temporal bones were analyzed and three-dimensionally reconstructed. A stepwise dissection technique for the TTA was demonstrated depending on a newly described landmark used in the identification of the facial nerve. The proposed landmark, which was named the intervestibulocochlear crest (IVCC), is an integrated part of the otic capsule. It can be differentiated after the excision of the lateral labyrinthine wall as a laterally based bony pyramid between the cochlea and the vestibule. Its medially directed apex blends with the central part of the falcifrom crest and points to the distal part of the meatal facial nerve. The IVCC is best detected on axial CT images at the level of the tympanic facial nerve. The union between the IVCC and the falciform crest appears radiologically as a short stem or mini-martini glass. The proposed IVCC is a novel landmark with a consistent relationship to the IAC fundus and the facial nerve. It may be utilized in conjunction with the falciform crest to identify the facial nerve during minimally invasive transcanal surgeries.

Seed ultrastructure and water absorption pathway of the root-parasitic plant Phelipanche aegyptiaca (Orobanchaceae)

Obligate root parasitic plants of the Orobanchaceae do not germinate unless they chemically detect a host plant nearby. Members of this family, like Orobanche, Phelipanche and Striga, are noxious weeds that cause heavy damage to agriculture. In spite of their economic impact, only a few light microscopical studies of their minute seeds have been published, and there is no knowledge of their ultrastructure and of the role each tissue plays during the steps preceding germination. This paper describes the ultrastructure of Phelipanche seeds and contributes to our understanding of seed tissue function. Seeds of P. aegyptiaca were examined under light, scanning electron, transmission electron and fluorescence microscopy following various fixations and staining protocols. The results were interpreted with physiological data regarding mode of water absorption and germination stimulation. The endothelium, which is the inner layer of the testa, rapidly absorbs water. Its interconnected cells are filled with mucilage and contain labyrinthine walls, facilitating water accumulation for germination that starts after receiving germination stimuli. Swelling of the endothelium leads to opening of the micropyle. The perisperm cells underneath this opening mediate between the rhizosphere and the embryo and are likely to be the location for the receptors of germination stimuli. The other perisperm cells are loaded with lipids and protein bodies, as are the endosperm and parts of the embryo. In the endosperm, the oil bodies fuse with each other while they are intact in the embryo and perisperm. Plasmodesmata connect the perisperm cells to each other, and the cells near the micropyle tightly surround the emerging seedling. These perisperm cells, and also the proximal embryo cells, have dense cytoplasmic contents, and they seem to represent the two seed components that are actively involved in transfer of reserve nutrients to the developing seedling during germination.

Ultrastructural aspects of the embryo and different endosperm compartments, inEruca sativaHill cv. Nemat (Brassicaceae) during Heart and Torpedo stages

Abstract These observations are the first on the ultrastructure of the embryo and the endosperm of Eruca sativa Hill. We investigated the cv. Nemat, which is characterized by a particularly high amount of lipids and glucosinolates. Our observations suggested that the thick and abundant micropylar endosperm, completely surrounding the suspensor, may be the main active source of nutrients for the embryo. This endosperm, like the central chamber endosperm, is particularly rich in functional chloroplasts and cellularizes later with respect to the other previ- ously investigated Brassicaceae. The last (distal with respect to the embryo) suspensor cell exhibits important features related to the passage of nutrients, such as wall ingrowths. In fact these ingrowths appear as highly convoluted labyrinthine wall projections. Such ultrastructural features are typical of transfer cells. The accumu- lation stage in E. sativa cv. Nemat appears to occur early (Heart stage of embryo development, as Brassica na pus). The ...

Recurrent bacterial meningitis after cochlear implantation in a patient with a newly described labyrinthine malformation

Authors report on a so far undescribed bilateral inner ear malformation with congenital deafness where a defect of both the medial and lateral bony labyrinthine wall allowed the herniation of a cerebrospinal fluid-filled endosteum sac into the tympanic cavity. The story of cochlear implantation in this ear and the series of following meningitis demonstrates the dilemma of indicating implantation in labyrinthine dysplasia and the difficulties of treating postimplantation meningitis. Routes of bacterial invasion from inner ear to intracranium is discussed regarding normal, dysplastic and surgically "disturbed" inner ear anatomy.

Ultrastructure of Placental Hyperplasia in Mice: Comparison of Placental Phenotypes with Three Different Etiologies

Hyperplastic placentas have been reported in several experimental mouse models, including animals produced by somatic cell nuclear transfer, by inter(sub)species hybridization, and by somatic cytoplasm introduction to oocytes followed by intracytoplasmic sperm injection. Of great interest are the gross and histological features common to these placental phenotypes – despite their quite different etiologies – such as the enlargement of the spongiotrophoblast layers. To find morphological clues to the pathways leading to these similar placental phenotypes, we analyzed the ultrastructure of the three different types of hyperplastic placenta. Most cells affected were of trophoblast origin and their subcellular ultrastructural lesions were common to the three groups, e.g., a heavy accumulation of cytoplasmic vacuoles in the trophoblastic cells composing the labyrinthine wall and an increased volume of spongiotrophoblastic cells with extraordinarily dilatated rough endoplasmic reticulum. Although the numbers of trophoblastic glycogen cells were greatly increased, they maintained their normal ultrastructural morphology, including a heavy glycogen deposition throughout the cytoplasm. The fetal endothelium and small vessels were nearly intact. Our ultrastructural study suggests that these three types of placental hyperplasias, with different etiologies, may have common pathological pathways, which probably exclusively affect the development of certain cell types of the trophoblastic lineage during mouse placentation.

Comparative anatomy of the chalazal endosperm cyst in seeds of the Brassicaceae

Data from this study show that the chalazal cyst is a consistent feature of the Brassicaceae that exhibits variation of potential taxonomic value. The U-shaped seeds of mustards comprise three development chambers: micropylar (MC), central (CC), and chalazal (ChC). Early in seed development the syncytial endosperm in the ChC becomes differentiated into a cyst that remains distinct from storage endosperm. In early syncytial stages, the cyst is stratified into three zones: (1) an apical zone containing nuclei, plastids and mitochondria, (2) a mid-zone rich in endomembranes but depleted of large organelles, and (3) a basal portion that is bordered by a labyrinthine wall. The basal zone has projections that range from foot-like extensions to thread-like haustoria that penetrate the underlying maternal chalazal proliferative tissues (CPT). No cell-to-cell connections occur between endosperm and maternal tissue, but the extensive labyrinthine walls closely invest cell lysate resulting from degradation of the CPT. Structural data from light, confocal and transmission electron microscopy suggest that the cyst is active in uptake and transport of metabolites into the developing seed. Four types of cyst reflecting position and size of the ChC are recognized. In general, they correlate with major tribes of Brassicaceae. Data support recent molecular studies indicating that classification of the Lepidieae is artificial and suggest that Thlaspi is a candidate for realignment. The most divergent morphology in a tribe is seen in the two species of the Hesperidae. Erysimum has a more typical chalazal chamber and cyst morphology while the tubular chalazal chamber and filiform cyst of Chorispora is of the most extreme type encountered in the survey. This suggests that the tribe is paraphyletic and should be reinvestigated to clarify relationships. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 144, 375−394.

Immunogold localization of callose and other cell wall components in pea nodule transfer cells

Transfer cells are located adjacent to xylem and phloem elements in pea nodule vascular tissues. The composition of the labyrinthine wall intrusions was investigated by immunogold labeling using specific antibody probes. Callose antigen was found at the base of newly formed cell wall intrusions and also in adjacent plasmodesmata. Sections through developed labyrinthine intrusions revealed that wall ingrowths had an internal structure with small domains of callose suggesting the presence of channels or vents. Xyloglucan and pectin antigens were uniformly distributed within the wall, but the distribution of extensin antigens was variable, with different antigens being detected in different regions of the wall ingrowth. A lectinlike glycoprotein, PsNLEC-1, was localized in intercellular spaces associated with nodule transfer cells. Previously, expression of this component was observed in other types of cells showing complex involution of the plasma membrane, namely root cortical cells harboring arbuscular mycorrhizae and nodule cells harboring nitrogen-fixing rhizobia.

Histopathological studies of intratemporal growth behavior of middle ear carcinoma

Otological hemorrhage otorrhea, and pain are amongst the first clinical signs of the middle ear carcinoma, which is usually diagnosed in advanced stages. Sudden deafness, facial nerve paralysis, and other symptoms of inner ear damage may be observed in the final stage. However, middle ear carcinoma is diagnosed extremely seldom in its early stages. The clinical management of this pathology is based on the knowledge of the tumor's pathways and its anatomic behavior. Our study investigated 20 cases of middle ear carcinomas from the Wittmaack temporal bone bank (14 squamous cell carcinomas, 5 adenocarcinomas, and 1 adenoidcystic carcinoma) to analyze the behavior of the tumor growth and its influence on clinical symptoms. The aim was to determine criteria for early clinical diagnosis. The tumor arises in different regions of the temporal bone, and varying symptoms will subsequently reflect its pathway. When the tumor is confined to the middle ear area, its main location is the hypotympanum from which tumor spreads into the eustachian tube and, via infiltration of the adjacent bone structures (anterior wall of the middle ear), into the tensor tympani muscle and the sympathetic plexus of the internal carotid artery. Destruction of the ossicles was observed in the mid-tympanic cavity, and often only a thin layer of fibrous tissue from the Fallopian canal separated the tumor from the facial nerve (this nerve was rarely affected directly). The medial wall (labyrinthine wall) of the tympanic cavity remained intact in the majority of examined cases. The tympanic sinus, the round window niche, and the oval window niche did not show tumor infiltration. In the epitympanum, the tumor grew and infiltrated the adjacent mastoid. Larger tumors affected the internal auditory canal and infiltrated the acoustic nerve and the labyrinth. Improving the poor prognosis of middle ear carcinoma requires early diagnosis based on axial computed tomography (CT). Important factors in patient selection include age (50-70 years), sex (mostly women), and especially clinical symptoms (otorrhea, pain, hearing loss).

Glucose transporter GLUT3 in the rat placental barrier: a possible machinery for the transplacental transfer of glucose.

Glucose transfer across the placental barrier is crucial for fetal development. To investigate the role of glucose transporter isoforms in the transplacental transfer of glucose, we investigated the localization of glucose transporters GLUT1 and GLUT3 immunohistochemically in the rat placenta. In the labyrinth, the site of maternofetal exchange of substances, both GLUT1 and GLUT3 were present, whereas only GLUT1 was detected in the junctional region. In the labyrinthine wall, which lies between maternal and fetal circulations, GLUT3 exhibited polarized localization; i.e. it was present at the plasma membranes of the maternal blood side in the syncytiotrophoblast layers. GLUT1 was concentrated at plasma membranes of the maternal and fetal blood sides of syncytiotrophoblast layers. The asymmetric distribution of GLUT3 across the placental barrier may suggest asymmetric transfer of glucose, which would be beneficial to provide a stable milieu for fetal development.

Ultrastructure of the Rodent Placental Labyrinth: A Site of Barrier and Transport.

The Placenta plays a pivotal role in the maternofetal exchange of substances. In the chorioallantoic placentas of rodents, maternal and fetal bloods come close in the labyrinth. Hemotrichorial placenta is formed in most of rodents including rat, mouse, and hamster. Three trophoblast layers composed of a single cytotrophoblast layer and two syncytiotrophoblast layers and endothelium of fetal capillaries lie between maternal and fetal circulations in the labyrinthine wall. Many gap junctions are present between syncytiotrophoblast layers. The double-syncytiotrophoblast layers connected by gap junctions serve as a structural basis of the placental barrier as well as a site of specific transfer of various substances. In the guinea pig placenta, only a single syncytiotrophoblast layer is formed, thereby it is classified as a hemomonochorial placenta. Endotheliochorial placenta was reported in the kangaroo rat. The ultrastructural features of the labyrinthine wall are described and discussed in relation to specific transplacental transfer of substances, especially glucose.

Sensory transduction of head velocity and acceleration in the toadfish horizontal semicircular canal

1. Sinusoidal mechanical indentation of the long-and-slender limb of the horizontal semicircular canal and/or utricle was used to produce adequate stimulation of the labyrinth. Indentation of the canal increased, while indentation of the utricle decreased the afferent discharge rate. This follows because indentation of the canal and utricle produce oppositely directed mechanical stimuli as defined by endolymph flow, transcupular pressure, and cupular deflection. Simultaneous in-phase indentations of both the canal and utricle, with amplitudes adjusted to produce equal (but opposite) magnitudes of afferent response modulation, generate destructive interaction that minimizes the afferent modulation, whereas sinusoidal indentation 180 degrees out-of-phase generates constructive interaction that maximizes the afferent modulation. This observation correlates directly with analysis of the labyrinthine elasto-hydrodynamics which predicts that balanced in-phase indentations minimize macromechanical endolymph flow through the ampullary cross section and maximize the dilatational pressure within the ampulla acting equally on both sides of the cupula and across the labyrinthine wall. 2. Two groups of afferents are identified according to their response to balanced sinusoidal indentation of the canal limb and the utricle. In one group there is complete destructive interaction and the afferent response can be effectively nulled by adjusting the relative amplitude and phase of the two stimuli. In the second group a residual afferent response remains that cannot be nulled. The residual is described in the model as unit-specific sensitivity to dilatational pressure acting equally on both sides of the cupula.

The Metabolic Status of Traumatic Gum Ducts in Moringa Oleifera Lam.

Traumatic gum ducts develop lysigenously in the bark of Moringa oleifera Lam. as a result of injury. The phloem parenchyma cells at the locus of gum duct formation enlarge and are enriched with cytoplasm and nucleoplasm. These duct initials show higher succinic dehydrogenase (SDH) and acid phosphatase (ACPase) activities compared to the neighbouring cells. The duct initials undergo autolysis to form the duct lumen. The epithelial cells of a gum duct have various shapes and show intense staining for nucleic acids, proteins and insoluble polysaccharides as compared to the neighbouring cells. The epithelial cells are also rich in enzymes viz. SDH, ACPase and lipase. Epithelial cells show labyrinthine wall deposition. These deposits are more towards the duct lumen side than the radial wall side. The inner tangential wall of the epithelial cells facing the duct lumen appears swollen. The degenerating epithelial cells show diffuse reaction products of SDH and ACPase. Some epithelial cells accumulate phenolics and by autolysis of such cells their phenolic contents are released into the gum duct.

Ontogeny of Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae. II. Transmission electron microscopy

Eucalyptus pilularis – Pisolithus tinctorius ectomycorrhizae were synthesized in growth pouches, and ultrastructural features of the two symbionts were documented during ontogeny. In the root cap – meristem zone, fungal hyphae envelop the root cap and penetrate between root cap cells. These fungal hyphae have numerous organelles and nuclei, some of which are in mitosis. The inner mantle hyphae in this zone and in the pre-Hartig net zone are heterogeneous in cytoplasmic content and are separated from the epidermis by an electron-dense layer. In the young Hartig net zone, hyphae penetrate between epidermal cells which contain electron-dense vacuolar deposits. In this zone and in the older Hartig net zone, hyphae do not penetrate beyond the epidermis and therefore a paraepidermal Hartig net is formed. The outer cortical layer develops as a hypodermis with suberized cell walls. The root–fungus interface consists of Hartig net hyphae which form a labyrinthine wall system and epidermal cells which are enlarged radially and contain electron-dense vacuolar deposits.

Localization of three sugar residues in the interface of ectomycorrhizae synthesized between Alnus crispa and Alpova diplophloeus as demonstrated by lectin binding

The interface established between Alnus crispa and the basidiomycete Alpova diplophloeus involves structural modifications of host cell walls and hyphal walls in the Hartig net region of the ectomycorrhizae synthesized in pouches. Indirect labelling of cell wall carbohydrates by using colloidal gold conjugated with the lectins Ulex europaeus agglutinin, wheat-germ agglutinin, and concanavalin A was applied to these mycorrhizae and to nonmycorrhizal roots. Significantly more binding of the lectins was observed in the mycorrhizal roots than in control roots. In the Hartig net region of mycorrhizal roots, the lectins bound intensely to the host cell wall, particularly the wall ingrowths, and to adjacent fungal walls, whereas in nonmycorrhizal roots, a sparse labelling was recorded in the cell wall. Possible explanations for this pattern of lectin binding include the following: the sugar residues L-fucose, mannose, and N-acetylglucosamine may be utilized in the synthesis of the elaborate epidermal wall ingrowths and N-acetylglucosamine may be utilized in the synthesis of the labyrinthine wall branchings of the fungus; the sugar residues are bound to a proteinaceous fraction in the host and hyphal walls; the sugar residues bound by the lectins may be components of defense reaction elicitors released from the host wall and hyphal wall by wall-degrading enzymes; the sugar residues may simply be the result of enzymatic degradation of walls but not involving elicitors of defense reactions.

Structure and ontogeny of Alnus crispa – Alpova diplophloeus ectomycorrhizae

Alnus crispa (Ait.) Pursh seedlings were grown in plastic pouches and inoculated with Frankia to induce nodules and subsequently with Alpova diplophloeus (Zeller & Dodge) Trappe & Smith to form ectomycorrhizae. The earliest events in ectomycorrhiza formation involved contact of the root surface by hyphae, hyphal proliferation to form a thin mantle, and further hyphal growth to form a thick mantle. Structural changes in the host, the mycosymbiont, and the fungus–epidermis interface were described at various stages in the ontogeny of ectomycorrhizae. Fungal hyphae in contact with epidermal cells in the regions of intercellular penetration and paraepidermal Hartig net developed numerous rough endoplastic reticulum cisternae. In more proximal regions of the mycorrhiza, these gradually became fewer in number and smooth. A complicated labyrinthine wall branching system also developed in the fungus in these regions. Concurrently, epidermal cells formed wall ingrowths in regions adjacent to Hartig net hyphae. There was a gradient in the formation of these epidermal transfer cells as the mycorrhiza developed, and an additional deposition of secondary cell wall over the wall ingrowths occurred as transfer cells senesced. Nonmycorrhizal control roots did not develop epidermal wall ingrowths. Electron-dense material, which was also autofluorescent, was deposited in the outer tangential walls of the exodermis contiguous to the paraepidermal Hartig net.

A Developmental Study of the Structure and Pollen Receptivity of the Macadamia Pistil in Relation to Protandry and Self-Incompatibility

The anthers of macadamia flowers dehisced 1-2 days pre-anthesis, but the stigma did not support pollen tube growth until 1-2 days post-anthesis. Esterase activity and extracellular secretion of carbohydrate, lipid, protein, and phenolics reached a peak at 1-2 days post-anthesis. The transmitting tract of the macadamia pistil had a complex structure with four distinct cell types with typical glandular ultrastructure. The stigma papillae and transmitting tissue (TT) cells at the base of the style had simple walls; the two types of TT cells in the upper style had labyrinthine wall thickenings. The inner TT cells of the upper style had thickenings on all walls from an early stage of development, whereas the outer cells had thickenings that developed following anthesis on the walls facing inner cells only. The thickenings of the outer, but not of the inner, cells stained for protein and phenolics. The pollen tubes grew between the inner and outer TT cells, and incompatible tubes were inhibited in this region. ...

Bone resorption in human cholesteatomas.

In vivo studies of different aspects of bone resorption in human cholesteatomas are described in the immunodeficient “nude” mice. Cholesteatoma membranes were transplanted into the middle ear cavities of the mice. After 21–28 days, growth of cholesteatoma tissue could be demonstrated in 8 of 13 animals. In 7 of these 8 animals bone resorption of the labyrinthine wall and ossicles could be demonstrated; resorption with acute inflammation was found in only two animals. The cellular mechanism in relation to bone resorption is discussed.