Inhibition of connexin 43 alters <Emphasis Type="Italic">Shh</Emphasis> and <Emphasis Type="Italic">Bmp-2</Emphasis> expression patterns in embryonic mouse tongue

The morphogenesis of fungiform papillae occurs in a stereotyped pattern on the dorsal surface of the mammalian tongue via epithelial–mesenchymal interactions. These interactions are thought to be achieved via intercellular communication. Gap junctions can be observed in many developing tissues and have been suggested to participate in a variety of functions, including the regulation of cell proliferation, differentiation, and apoptosis. Here, we demonstrate that the expression of Connexin 43 (Cx43), a gap junction protein, is correlated significantly with the development of fungiform papillae, which exhibit a pattern formation and morphogenesis similar to the development of other epithelial appendages. Antisense-oligodeoxynucleotide (AS-ODN) against Cx43 was used to assess the developmental functions of Cx43. The expression patterns of the signaling molecules were disrupted by Cx43 inhibition. Interestingly, the expression patterns of Shh, a key molecule in the determination of the spacing patterns of fungiform papillae, were disturbed after treatment with Cx43 AS-ODN. We have also attempted to determine the functions of Bmp-2 by applying NOGGIN protein to tongue cultures. Our results indicate that upstream regulation via Cx43 controls the Shh and Bmp-2 pathways for the morphogenesis and pattern formation of fungiform papillae.This work was supported by grant no. R01-2003-000-11649 from the Korea Science and Engineering Foundation.     

Fibroblast and epidermal growth factors modulate proliferation and neural cell adhesion molecule expression in epithelial cells derived from the adult mouse tongue

Lingual epithelial cells, including those of the taste buds, are regularly replaced by proliferative stem cells. We found that integrin beta(1), a keratinocyte stem cell marker, was expressed at the basal layer and taste buds of adult mouse tongue epithelium. We purified and cultured integrin beta(1)-positive cells (termed KT-1 cells), whose growth was stimulated by epidermal growth factor (EGF) and basic fibroblast growth factor (FGF-2). FGF-2 stimulation induced translocation of the FGF type I receptor (FGFR1) into nuclei, suggesting that the growth-stimulating effect of FGF-2 was mediated through FGFR1. EGF and FGF-2 also regulated cell surface expression of the neural cell adhesion molecule (N-CAM) in KT-1 cells. Anti-N-CAM antibody immunoreactivity was restricted to the gustatory epithelium and the nerves in the tongue epithelium, giving rise to the possibility that KT-1 may contain gustatory epithelial cells. KT-1 cells may thus be useful for analyzing the factors that regulate the growth and differentiation of lingual and gustatory epithelial cells in vitro.     

The function of anal papillae in salt adaptation of Drosophila melanogaster larvae

The anal papillae of Drosophila melanogaster larvae showed strong developmental plasticity in media with different osmotic pressure. The size of the papillae decreased with increasing salt content of the medium, which supports the hypothesis of its absorptive function. We showed that CI-transport at the site of the anal papillae decreased with increasing salt concentration, which also supports the hypothesis, that the function of anal papillae in osmoregulation is absorption at low salt content and not excretion at high salt content. The inactive area between the anal papillae increased with increased salt concentration, and thus contributed to the decreasing size of the anal papillae. Remnants of this area in pupae were mistakenly measured as anal papillae in a study on salt adaptation by Waddington (1959).     

华支睾吸虫在大鼠体内发育的扫描电镜观察

华支睾吸虫在大鼠体内发育中,随着体长的增大,体表上的细微结构也发生了比较明显的变化。包括体嵴增高,继而形成许多结节,并由结节上发出点状,指状或枝状突起;体棘逐渐减少和消失;腹吸盘唇上和口、腹吸盘周围的感觉乳突数量明显增多。     

Observations on the Morphology of the Pine Wood Nematode, Bursaphelenchus xylophilus

Scans of slash pine wood chips infested with pine wood nematodes showed coiled aggregates of 5-10 nematodes in the axial resin canals, and 1-2 nematodes folded in the radial resin canals. Observations of the pine wood nematode by SEM showed the head to be offset with six labial lobes. A smaller circle of six inner lobes surrounded the stoma. A single labial sensillum was observed on each of the two subventral and two subdorsal lobes. The two opposite lobes, without sensilla, bore a pore-like amphid. The female vulva flap was observed to be a pouch. In addition to two pairs of copulatory papillae previously described for the male, three additional papillae were observed: an additional post-anal pair, and a single papilla anterior to the cloaca. Spicules were fused ventrally. Distal spicule ends terminated in two fused half discs. Caudal alae were angular at the tail terminus, but culed inward at the corners to appear oval. Lateral fields had four lateral striations.     

Fine Structure of Cephalic Sense Organs in Meloidogyne incognita Males

Amphids, and the cephalic and labial papillae of Meloidogyne incognita males were examined in detail by electron microscopy. Each amphid basically consists of an amphidial gland, a nerve bundle and an amphidial duct. The gland is a broad microvillous organ with a narrow anterior process, which is closely associated with the amphidial duct. A posterior process of the gland contains secretory organelles and proceeds along the esophagus with the lateral cephalic nerve bundle. The nerve bundle penetrates the broad portion of the gland and, subsequently, individual nerve processes (dendrites) separate from one another, thus forming the sensilla pouch which is enveloped by the gland. Anterior to the pouch, the dendrites converge as they enter and eventually terminate in the amphidial duct. The external opening of the duct is a broad slit which separates the cheek, the outermost part of the lateral lip, from the remainder of the lip region. M. incognita males have six inner labial papillae and four outer cephalic papillae which are each innervated by two and one cilia, respectively. In labial papillae, the cilia appear to terminate at the base of a pore opening, whereas in cephalic papillae each cilium terminates beneath the labial cuticle.     

Elektronenmikroskopische Untersuchungen zur Struktur und Funktion der Rektalpapillen von Drosophila melanogaster

Zusammenfassung Die Zellen der vier Rektalpapillen von Drosophila melanogaster sind polar gebaute, hochdifferenzierte, transportaktive Zellen mit großflächigen Ein- und Ausfaltungen des Plasmalemms. Ihre basale und laterale Zellmembran bildet ein Netzwerk von Einfaltungen, aus dem zahlreiche Stapel von Membranpaaren hervorgehen, die mit Mitochondrien vergesellschaftet sind. Apikal besitzt die Zelle ein System von Mikroleisten, an deren Basis ebenfalls Mitochondrien akkumuliert sind (s. Abb. 9). Bei Drosophila werden nach Durchführung der entsprechenden elektronenmikroskopischen Nachweise Natriumionen an den Membranen der apikalen Ausfaltungen, an den Membranen der interzellulären Stapel der Membranpaare, innerhalb deren Lumina und in den basalen und lateralen Einfaltungen gefunden. Eine bevorzugte Lokalisation von Chloridionen ist nicht vorhanden.Diese Feinstrukturaspekte und die Ergebnisse der Nachweisreaktionen für Natrium und Chloridionen werden mit den Verhältnissen bei Calliphora erythrocephala (Gupta und Berridge, 1966) verglichen und die Transportwege der Ionen eingehend diskutiert.

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Electron microscopic studies on the structure and function of the rectal papillae in Drosophila melanogaster

Summary In Drosophila melanogaster the cells of the rectal papillae are highly differentiated and very active in transport. These cells show extensive infoldings of the plasmalemma. The basal and lateral cell membranes form a system of infoldings, continuous with intracellular stacks of paired membranes which are associated with mitochondria. The apex of the cell displays a system of micro-ridges with basal mitochondria (see Fig. 9). In Drosophila Na⁺ ions can be demonstrated by electron microscopy at the membranes of the apical micro-ridges, at the membranes and within the lumina of the intracellular stacks of paired membranes, and within the basal and lateral infoldings. In contrast, there is no predominant localization of Cl^– ions. The fine structure of the cells of the rectal papillae and the results of cytochemical demonstration of Na⁺ and Cl^– ions are compared with the findings of Gupta and Berridge (1966) in Calliphora erythrocephala. The possible pathways for ion transport are discussed in detail.

Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Morphological,ultrastructural and histochemical investigation of epipodial sensory structures of Haliotis tuberculata (Gastropoda: Haliotidae)

In this study, we describe the microstructure and ultrastructure of the epipodial papillae and epipodial tentacles of Haliotis tuberculata using light and electron microscopy. The epipodial papillae vary morphologically; they are subdivided into several subpapillae whose surface is covered by small micropapillae. The epipodial tentacles are large extendable conically elongated structures whose surface is differentiated in two regions: the dorsal region with long corrugated folds, and a ventral region composed of three parts, a basal part with the same structure as the dorsal, a middle part with shorter corrugated folds and an apical part with large micropapillae. Although the thin sections and ultrastructure examination show that the epithelium of both organs is morphologically similar and composed of supporting cells, sensory cells and different types of secretory cells, there is a certain specialization in their secretory product. Although the epithelium of both structures was positive for acidic glycoconjugates, the tentacle epithelium was also positive for neutral sugars. Further specific differences were revealed by lectin histochemistry. Because papillae and tentacles can be extended or retracted depending on environmental conditions, they probably have tactile and olfactory functions.     

Calcium propionate supplementation improves development of rumen epithelium in calves via stimulating G protein-coupled receptors

In the present study, calcium propionate (CaP) was used as feed additive in the diet of calves to investigate their effects on rumen fermentation and the development of rumen epithelium in calves. To elucidate the mechanism in which CaP improves development of calf rumen epithelium via stimulating the messenger RNA (mRNA) expression of G protein-coupled receptors, a total of 54 male Jersey calves (age=7±1 days, BW=23.1±1.2 kg) were randomly divided into three treatment groups: control without CaP supplementation (Con), 5% CaP supplementation (5% CaP) and 10% CaP supplementation (10% CaP). The experiment lasted 160 days and was divided into three feeding stages: Stage 1 (days 0 to 30), Stage 2 (days 31 to 90) and Stage 3 (days 91 to 160). Calcium propionate supplementation percentages were calculated on a dry matter basis. In total, six calves from each group were randomly selected and slaughtered on days 30, 90 and 160 at the conclusion of each experimental feeding stage. Rumen fermentation was improved with increasing concentration of CaP supplementation in calves through the first 30 days (Stage 1). No effects of CaP supplementation were observed on rumen fermentation in calves during Stage 2 (days 31 to 90). Supplementation with 5% CaP increased propionate concentration, but not acetate and butyrate in calves during Stage 3 (days 91 to 160). The rumen papillae length of calves in the 5% CaP supplementation group was greater than that of Con groups in calves after 160 days feeding. The mRNA expression of G protein-coupled receptor 41 (GPR41) and GPR43 supplemented with 5% CaP were greater than the control group and 10% CaP group in feeding 160 days calves. 5% CaP supplementation increased the mRNA expression of cyclin D1, whereas did not increase the mRNA expression of cyclin-dependent kinase 4 compared with the control group in feeding 160-day calves. These results indicate that propionate may act as a signaling molecule to improve rumen epithelium development through stimulating mRNA expression of GPR41 and GPR43.     

Scanning electron microscopy of the leaf epidermis in Arundinarieae (Poaceae: Bambusoideae): evolutionary implications of selected micromorphological features

Arundinarieae (temperate woody bamboos) is a taxonomically challenging group and the taxa in this tribe show a low level of DNA sequence variation, especially for plastid markers. As a result of the scarcity of flowering collections, species identification mainly depends on vegetative features, and leaf epidermal micromorphology has proven to be useful in bamboo taxonomy. In this study, we used scanning electron microscopy to investigate the abaxial leaf epidermal micromorphology of 94 species in 24 genera of Arundinarieae and three species of Bambuseae. Leaf epidermal characteristics differed mainly in the number and distribution pattern of papillae. Seven papilla forms were assigned, which had little taxonomic value at the generic and subtribal levels. However, the papilla patterns combined with other leaf epidermal features were useful in the discrimination of several species. Most papilla types were shared between tribes Arundinarieae and Bambuseae. We assessed the phylogenetic implications of the leaf epidermal micromorphology based on recently published molecular phylogenetic analyses. With one exception, none of the papilla types corresponded to a particular clade in the plastid or nuclear phylogenetic trees. Based on these results, the papilla patterns have limited phylogenetic value. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176 , 46–65.