Small Protuberances Research Articles

A new species of marine Gastrotricha from Maine, USA: Tetranchyroderma mainensis (Macrodasyida, Thaumastodermatidae)

A new species of pentancrous thaumastodermatid (Phylum Gastrotricha, Order Macrodasyida), Tetranchyroderma mainensis sp. nov., is described from an unusual sandy overwash in the upper intertidal zone at Griffiths Head, Reid State Park, Maine, USA. The species differs from others in the genus by its large size (adults to 750 µm), by the continuous series of ventral post-oral adhesive tubes that runs from side to side (TbA 22 with 2 per side behind this series and 6 longer tubes per side lateral to the mouth), by numerous tubes inserting along the lateral surfaces (>50 TbL, TbVL), and by small cephalic protuberances borne dorsally.

Investigation on the crystal growth process of spherical Si single crystals by melting

Spherical Si single crystals with a diameter of approximately 1 mm were grown by melting for solar cell applications. The start sources were spherical Si multicrystals fabricated by a dropping method, which had various irregular shapes. Spherical Si multicrystals were melted into droplets and recrystallized on a quartz plate sample holder that was coated with Si 3N 4. It was found that a surface coating of SiO 2 layer on the start sources and oxygen atmosphere during melting and recrystallization were essential to achieve almost perfect spherical shape. Defect-free single crystalline spherical Si could be obtained at recrystallization temperature ranging from 1400 to 1330 °C, corresponding to an undercooling ranging from 14 to 84 °C, with a yield of nearly 100%. At recrystallization temperatures higher than 1380 °C, the recrystallized spherical Si crystals were almost perfect spheres, whereas small protuberances were formed when the recrystallization temperature was lower than 1360 °C. It was also found that that melting at a temperature close to the melting point of Si (at ~1414 °C), a slow cooling rate of ~1 °C/min before recrystallization and relatively fast cooling rate of ~20 °C/min after recrystallization were important for achieving high carrier lifetime. The average carrier lifetime was greatly improved from lower than 2.5 μs of start sources up to ~7.5 μs by melting at optimized conditions. The influences of residual oxygen on the carrier lifetime of recrystallized spherical Si are discussed based on the measurement results with Fourier transform infrared spectrometer.

Splitting of transmission peak due to the hole symmetry breaking

We studied experimentally and theoretically the optical transmission through asymmetrical holes of a metal film, which is constructed by introducing small protuberances to the sides of individual square holes. Due to the symmetry breaking of the hole shape, an interesting transmission feature appears: both the Ag-glass (1, 0) and Ag-glass (1, 1) peaks split distinctly. Detailed studies indicate that the peak splitting is actually associated with the two asymmetrical waveguide surface-plasmon (WSP) modes confined on the surface of opposite hole walls. The finding demonstrates the crucial role of WSP modes and enriches our understanding of the phenomenon.

Thallus structure and isidium development in two Parmeliaceae species (lichenized Ascomycota)

(Thallus structure and isidium development in two Parmeliaceae species (lichenized Ascomycota)). Conventional techniques for structural studies under light microscope and scanning electron microscope were employed to describe and compare the histology of thallus and isidia development in Parmotrema tinctorum and Parmelinopsis minarum. Although presenting layers typical of the heteromerous structure of Parmeliaceae lichens, the studied species have very distinct anatomical details including: the type of upper cortex, medulla thickness, hyphal orientation pattern and distinct strata in this layer, variations of crystal shape, color, location and degree of association with medullary hyphae, rhizines thickness and covering by a cortical layer. Isidium formation starts with cortical cell proliferation, which results in a small protuberance on the thallus surface, followed by the photobiont cell proliferation. Medullary hyphal intrusions occur only after the formation of this protuberance. In this stage medullary hyphae grow, ramifying or not inside the protuberance. In a posterior stage, the isidium base becomes constricted, which facilitates its detachment from the thallus.

Three species of Pseudotaeniacanthus Yamaguti & Yamasu, 1959 (Copepoda, Taeniacanthidae) parasitic on laced moray (Gymnothorax favagineus) in Taiwan

ABSTRACT Three new species of Pseudotaeniacanthus Yamaguti & Yamasu, 1959 were discovered infesting gill filaments of the laced moray, Gymnothorax favagineus Bloch & Schneider, caught off southern Taiwan. Two of these species, P. dentiferus, new species and P. similis, new species, are distinguished from their congeners by the presence of a tooth-like projection on the ventral side of the proximal segment of their antennule. Pseudotaeniacanthus similis differs from P. dentiferus in having a plumose seta (instead of a spine) on the outer margin of the terminal, endopodal segments of legs 2–4. The third species, P. conspicuus, new species, is distinguished by the presence of a rostral bar partially visible in dorsal view and a small protuberance on the posterolateral margin of the cephalothorax. A key to the 11 species of Pseudotaeniacanthus is provided.

ATR/Raman and Fractal Characterization of HPBCD/Progesterone Complex Solid Particles

Characterization of hydroxypropyl-beta-cyclodextrin/progesterone (HPBCD/P) complex solid particles obtained from an aqueous solution, by three different technological processes, with the aim of preparing ready-to-dissolve powders for injectable as well as solid oral formulations in progestinic therapy. HPBCD/P complex in the 2:1 molar ratio was prepared in aqueous solution and obtained as dry solid particles by freeze-drying, by spray-drying and by fluid-bed evaporation of the solvent. The particles were characterized by mu-FT-IR, mu-Raman and X-ray spectroscopy, by thermal analysis (differential scanning calorimetry-DSC and thermogravimetry-TGA), by Karl Fischer (KF) titration, by image and fractal analysis and by BET specific surface area analysis. The structure of the complex was also defined by comparison of FT-IR and Raman spectra of progesterone with those of pregnenolone and testosterone, structurally related. Dissolution tests were also performed. Powders of the complex obtained by the three different methods are different in size and shape. Particles obtained by freeze-drying are flat and angular, irregularly shaped without any relation to known geometrical solid figures. Particles obtained by spray-drying are spherically shaped and display a very small size (5-10 microm), with evident deformations and depression of the external surface, due to the rapid evaporation of the solvent. Particles obtained by fluid bed technique have intermediate sizes, display a tri-dimensional structure and irregular surface, with small and rounded protuberances. Fractal dimension of the particle contour was found close to one unit for the microspheres obtained by spray-drying. FT-IR and Raman spectra confirm the occurrence of the complexation by the shift of representative bands of the two carbonyl groups in positions 3 and 20 of the complexed progesterone. X-ray diffractograms indicate the amorphous nature of all the types of particles, also suggested by the absence of any melting peak of the drug in DSC thermograms. The samples contain different amounts of humidity: particles obtained by fluid-bed method demonstrated non-porous in BET analysis. Dissolution of different types of particles is complete after 3 min and only negligible differences could be appreciated among the three powders. - mu-FT-IR, mu-Raman and X-ray spectroscopy, and the dissolution test did not reveal defined differences among the three different types of particles, confirming occurrence of the complex in the solid state. The spherical shape, the very small size and the low value of the contour fractal dimension allows better technological performance of the particles obtained by spray-drying: this drying process appears the most promising one to prepare dry particles of the HPBCD/P complex, in view of its formulation in the fast preparation of extemporaneous injectable solutions and solid oral formulations intended for sublingual delivery.

Reproductive anatomy of male Southern Emu-wrens (Stipiturus malachurus) and Striated Grasswrens (Amytornis striatus)

In birds, several features of male reproductive anatomy vary with the degree of promiscuity and the intensity of sperm competition. We describe the male reproductive anatomy of the Southern Emu-wren (Stipiturus malachurus) and the Striated Grasswren (Amytornis striatus) in the context of sperm competition. Male Southern Emu-wrens exhibited a very low relative testes size of just 0.6% of male body mass, lacked a cloacal protuberance and possessed a relatively small seminal glomera containing an average of just 12.6 × 106 sperm. Male Striated Grasswrens exhibited relatively small testes, comprising 1.78% of male body mass, and small cloacal protuberances. The relative size of the seminal glomera was also small and seminal glomera contained an average of 42.5 × 106 sperm. When compared with the well-studied fairy-wrens (Malurus) and based on male reproductive anatomy, it appears that emu-wrens experience a relatively low level, and grasswrens an intermediate level, of sperm competition.

A comparative ultrastructural investigation of the cephalic sensory organs in Opisthobranchia (Mollusca, Gastropoda)

Cephalic sensory organs (CSOs) are specialised structures in the head region of adult Opisthobranchia involved in perception of different stimuli. The gross morphology of these organs differs considerably among taxa. The current study aims at describing the cellular morphology of the CSOs in order to reveal cellular patterns, especially of sensory epithelia, common for opisthobranchs. Transmission electron microscopy was used to characterise the fine structure of the organs and to compare the CSOs of four different opisthobranch species. The cellular composition of the sensory system is conserved among taxa. The epidermal cells in sensory regions are always columnar and ciliated cells are frequently apparent. The sensory cells are primary receptors arranged in subepidermal cell clusters. They extend dendrites which penetrate the epithelium and reach the surface. Some of the dendrites bear cilia, whereas others only build a small protuberance. Processing of sensory information takes place in the peripheral glomeruli of all species. Moreover, few taxa possess additional peripheral ganglia at the base of their CSOs. The results of the present study might support other investigations indicating that the posterior CSOs are primarily involved in distance chemoreception, whereas the anterior CSOs might be used for contact chemoreception and mechanoreception.

Preliminary tribological evaluation of nanostructured diamond coatings against ultra‐high molecular weight polyethylene

Some loss of joint prostheses has been attributed to osteolytic loosening associated with debris from wear of polyethylene articulating against metal alloys. Reduced polyethylene wear has been reported with ceramics serving as an alternative counterface. Nanostructured Diamond (NSD) coatings were deposited onto Ti6Al4V by microwave plasma-assisted chemical vapor deposition, with both hydrogen-rich (H-NSD) and helium-rich (He-NSD) feedgas mixtures. Pin-on-disk wear tests of polyethylene against NSD and CoCr were performed in serum lubrication at body temperature. Scanning electron microscopy was used to examine surface morphology, and nanoindentation was used to determine hardness and modulus of the polyethylene wear surfaces. Raman spectroscopy, surface roughness, and wettability analyses of the NSD coatings were performed. Raman spectroscopy confirmed sp(2) and sp(3) bonded carbon in the NSD coatings. No significant differences in wear factors were found between polyethylene on H-NSD, He-NSD, and CoCr, despite higher roughness and friction coefficients for the He-NSD and H-NSD coatings, compared with CoCr. Contact angles for the diamond coatings were reduced following the wear tests, indicating that these surfaces became more hydrophilic. Numerous small protuberances were observed on pins articulated against CoCr, and a single, large protuberance was observed in polyethylene-on-NSD. These features were conjectured to be reconsolidated polyethylene particles. Nanoindentation modulus and hardness of the worn polyethylene surfaces were lower for polyethylene-on-diamond than for polyethylene-on-CoCr. As a counterface to polyethylene, NSD-coated Ti6Al4V produced wear factors comparable to CoCr in the present pin-on-disk tests, a promising step towards its use in joint replacement bearing applications.

Morfologia externa de espécimes adultos de Paratanaisia bragai (Santos, 1934) (Digenea: Eucotylidae)

Adult specimens of Paratanaisia bragai collected from renal ducts of Columba livia naturally infected, were fixed in glutaraldehyde 2.5 degrees and processed for scanning electron microscopy. Two distinct types of scales had been identified, bifid and simple scales, disposed in transversal rows, on the tegument of dorsal and ventral face of the body. Also show in details the oral sucker subterminal, well developed and acetabulum of size reduced, located in third medium of the body, surrounded for small protuberance and four papillae on its edge.

Symptomatology and morphology of Claviceps cyperi on yellow nut sedge in South Africa

Symptoms of ergot on yellow nut sedge, germination of sclerotia of the causal organism, Claviceps cyperi, and morphology of fresh specimens of the pathogen are described for the first time. The initial symptom of infection was a black sooty layer on inflorescences of infected plants due to colonization of the ergot honeydew by Cladosporium cladospor-ioides. Sclerotia of C. cyperi started to develop in March and April and could be discerned as small protuberances on inflorescences in the place of seed. Mature sclerotia were purplish-black. They generally remained viable for less than a year and germinated without prior cold treatment, although exposure for 21 d to 5 C before incubation significantly increased the germination rate. Under moist conditions at 24 C in the laboratory, germination commenced within 4–8 wk. Stromata took about 12 d to mature. Mature capitula were distinctly lobulate with a perithecium embedded in each lobe and a collar-like appendage around the base. Although dimensions of sclerotia, stipes, capitula, asci and ascospores were larger than in the original description, the general morphology supports treatment of C. cyperi as a distinct species.

Symptomatology and morphology of Claviceps cyperi on yellow nut sedge in South Africa

Symptoms of ergot on yellow nut sedge, germination of sclerotia of the causal organism, Claviceps cyperi, and morphology of fresh specimens of the pathogen are described for the first time. The initial symptom of infection was a black sooty layer on inflorescences of infected plants due to colonization of the ergot honeydew by Cladosporium cladosporioides. Sclerotia of C. cyperi started to develop in March and April and could be discerned as small protuberances on inflorescences in the place of seed. Mature sclerotia were purplish-black. They generally remained viable for less than a year and germinated without prior cold treatment, although exposure for 21 d to 5 C before incubation significantly increased the germination rate. Under moist conditions at 24 C in the laboratory, germination commenced within 4-8 wk. Stromata took about 12 d to mature. Mature capitula were distinctly lobulate with a perithecium embedded in each lobe and a collar-like appendage around the base. Although dimensions of sclerotia, stipes, capitula, asci and ascospores were larger than in the original description, the general morphology supports treatment of C. cyperi as a distinct species.

Asexual reproduction in homoscleromorph sponges (Porifera; Homoscleromorpha)

Asexual reproduction by external budding in Homoscleromorpha is reported for the first time. Two Mediterranean sponge species were studied, Oscarella lobularis and O. tuberculata. Buds are formed in the marginal basal part of sponge. Budding takes from 1 to 4 days and is defined in three budding stages. First, small irregular protuberances, consisting of external parental tissue, are formed. Second, they elongate and acquire more regular, nipple-like shape. These protuberances are tube like, their internal cavity derived from parental exhalant canal. The wall consists of three layers: (a) external layer is flagellated exopinacoderm, (b) internal one is flagellated endopinacoderm and (c) intermediate one is a thin layer of mesohyl. Third, a spherical bud with a large central cavity is formed. During budding, we did not observe cell proliferation or transdifferentiation either in budding zone or in any special mitotically active region. The bud attached to the substrate is similar to the rhagon developing after larva metamorphosis, it has a syconoid organization. Morphogenetically, budding in Oscarella differes from that in other sponges. Occurring by epithelial morphogenesis, it is similar to morphallaxis during regeneration. The presence in Homoscleromorpha of an epithelial morphogenesis is unique among sponges. This feature is shared by Homoscleromorpha and Eumetazoa.

MORPHOLOGICAL DIFFERENTIATION AND FUNCTION OF THE COELOMOCYTES IN THE PARASITIC STAGES OF NIPPOSTRONGYLUS BRASILIENSIS

Female and male worms of Nippostrongylus brasiliensis exhibited sexual dimorphism based on the number of coelomocytes present. A surprising multiplicity of diverse morphological types of coelomocytes developed in both female and male worms during the parasitic cycle. Cytoplasmic processes began to appear on the surface membrane of coelomocytes in the late third-stage larvae (L3s) in the lungs, and they increased greatly in type, size, and morphology during the fourth and fifth stages. These structures were characterized primarily as complex filopodia, pseudopodia, and cytoplasmic pearls, which resulted in the formation of highly pleomorphic cells. Pearls, starting as small protuberances, progressively increased in size and number with larval growth and development. In the adult worms, a novel process of autocannibalism was initiated in many of the very large coelomocytes. The pearls grew enormously in size at the expense of the cytoplasm, forming a peripheral garland in 1 plane surrounding a residual, small, flat, cytoplasmic core containing the nucleus. The underlying "strategy" was to increase the surface-to-volume ratio of these huge cells to overcome the restriction imposed by eutely; the coelomocytes do not undergo cell division. This morphological innovation makes possible a more efficient uptake of nutrients and exocytosis of waste matter. Vesicles (presumably lysosomes) in the coelomocytes of the infective L3 store an extraordinarily high concentration of vitamin B12 (cobalamin, Cbl). At present, the only physiological function that can be assigned to coelomocytes of N. brasiliensis is the uptake, concentration, and storage of Cbl in the free-living stages, with the subsequent release of the molecule from the vesicles in the early phase of parasitism. Thus, stored Cbl in the infective L3 is made available for biochemical processes during the critical period of larval growth and differentiation initiated in the lung. A model of a hypothetical coelomocyte is presented relative to the processing and use of Cbl. Based on many criteria, it is possible that functional differences exist between different morphological types of coelomocytes in the parasitic stages of N. brasiliensis and that future studies will have to address this matter.

On streamwise vortices and their role in the development of a curved wall jet

The streamwise growth of longitudinal vortices in a curved wall jet was investigated experimentally, mostly through Particle Image Velocimetry (PIV). This growth was partially achieved through amalgamation of neighboring vortices having the same sense of rotation and partially due to centrifugal instability, thus the average spacing of the vortices far downstream was independent of the protuberances (micro vortex generators) that initiated them at the slot lip. The spacing of these protuberances along the span established only the preferred distance from the nozzle where vortex amalgamations occurred. The streamwise vortices initiated spanwise undulations in the mean flow creating a radial component of vorticity that when examined at a given distance from the surface was found to be inviscidly unstable, and could enhance further this component of vorticity. A strong coupling was observed between plane periodic excitation of the nozzle-flow and the small stationary protuberances that were placed at the nozzle in the presence of curvature. This coupling enhanced the coherence and strength of the longitudinal vortices far downstream from the nozzle, while in the absence of curvature these structures simply decayed.

First Report of Two Nematode-trapping Fungi, Monacrosporium ullum sp. nov. and Arthrobotrys amerospora, from Korea

Monacroporium ullum sp. nov. the captures nematodes on adhesive spherical knobs was isolated from soil around Codonopsis lanceolata at Ulleung island, Korea. The spindle-shaped conidia sized <TEX>$17-44{\mu}m\;(26.5{\mu}m)\;long,\;7-10{\mu}m\;(8.1{\mu}m)$</TEX> wide, containing from 1 to 4 cross-walls but most often divided by 2 septa (47%). Resting bodies sized <TEX>$57{\times}30{\mu}m$</TEX>. Arthrobotrys amerospora has almost spherical non-septate conidia with a small truncate protuberance at the base and sized <TEX>$20-27{\mu}m\;(23.3){\mu}m$</TEX> long and <TEX>$11-17{\mu}m\;(14.1){\mu}m$</TEX> wide. Conidiophores are somewhat longer <TEX>$362.8{\mu}m\;(311-418{\mu}m)$</TEX> than its original description (<TEX>$75-250{\mu}m$</TEX>).

Morphological characteristics of Quercus variabilis charcoal prepared at different temperatures

The morphology of charcoals was investigated by scanning electron microscopy. Charcoal of Quercus variabilis was prepared in an electric furnace under nitrogen gas atmosphere at 400, 600, 800 and 1,000°C. Charring temperature greatly affects the structure of charcoal. In charcoal prepared at 400°C, most of the morphological characteristics remained relatively unchanged with the exception of the cell-wall layering. The cell walls appeared homogenous and glass-like. Above 400°C, there was an increase in cell-wall thinning and volumetric shrinkage with an increase in the charring temperature. These two factors were responsible for most of the observed changes in structure. Fracture surfaces became increasingly rough and disrupted. Vessel elements were increasingly distorted and tyloses disintegrated with increases in temperature. Parenchyma cells exhibited greater shrinkage except at the pits. This resulted in the appearance of distinctive small protuberances over the surface of the parenchyma cells. Rhomboidal calcium crystals were found to be abundant at all the temperatures studied, but at 800 and 1,000°C the crystals had a sponge-like appearance.

Induction of callus and somatic embryogenesis from cotyledon explants of Parkia biglobosa (Jacq.) Benth

To explore the potential for in vitro rapid regeneration of Parkia biglobosa , an endangered multipurpose woody angiosperm, cotyledon explants obtained from 7-day old aseptically germinated seedlings were cultured on Murashige and Skoog (MS) basal medium supplemented with 0.4-1.0 mg/L naphthalene acetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4-D). Cotyledon explants were placed either with the abaxial surface facing up or down on the media. Induced calli were subcultured on media containing 0.8 mg/L Kinetin combined with different concentrations (0.2, 0.6 and 1.0 mg/L) of 2,4-D. Unlike in NAA, successful calli induction was observed in all concentrations of 2,4-D investigated. Callus production was only at the cut edges and on the abaxial surface of the explants. Induced calli turned friable, more nodular and with small protuberances on media containing 0.8 mg/L Kinetin combined with either 0.2 mg/L or 0.6 mg/L 2,4-D. The protuberances eventually developed into somatic embryos in an auxin-free suspension culture medium. The developed protocol established the potential to produce plantlets from cotyledon explants through somatic embryogenesis. It also offers itself as a highly efficient method for mass clonal propagation and conservation of P. biglobosa . Key words: Parkia biglobosa , callus induction, somatic embryogenesis, cotyledon explants. African Journal of Biotechnology Vol.4(1) 2005: 68-71

Aonidiella citrina

<i>Aonidiella citrina</i>

Living under an atomic force microscope

ABSTRACTAn approach for long‐term in vivo investigations on cyanobacterial cell surface changes at high spatial resolution by Atomic Force Microscopy (AFM) was developed in this study.Until recently, changes of bacterial cell surfaces due to changes of the chemical environment could neither be investigated in situ nor in vivo. However, in vivo investigations give insights into kinetics of cell response to environmental changes and mineral nucleation at the cell's surface. Continuously cultured cyanobacteria of the representative freshwater strain Synechococcus leopoliensis (PCC 7942) were washed and artificially immobilized on poly‐l‐lysine‐coated glass slides. Both immobilization and environmental conditions were optimized in order to facilitate long‐term experiments (&gt; 100 h) with living cells. AFM samples were investigated in situ in two different solutions: Culture medium was used for cultivation experiments and nutrient‐free NaHCO3/CaCl2 solutions (supersaturated with respect to calcite) for long‐term characterizations of the changes in cell surface topography. Cell viability under these conditions was investigated by AFM, TEM and epifluorescence microscopy, independently.No indications for extended starvation were found within the relevant timescales. Analysing the influence of Ca2+ on the surface of S. leopoliensis, we found significant changes compared to a Ca‐free solution. Few hours after CaCl2 was added to the circumfluent solution, small protuberances were observed on the cell surface.These are promising results to environmental scientists for a wide range of applications, as cell response to environmental changes can now be monitored online and in vivo at timescales, which are relevant for natural processes. Most especially studies of biomineralization and mineral nucleation on bacterial cell surfaces will profit from this new approach.