Formation Of Protuberances Research Articles

Fruiting Body Heterogeneity, Dimorphism and Haustorium-like Structure of Naematelia aurantialba (Jin Er Mushroom).

Mushroom Jin Er has attracted widespread attention in Asia over the past two decades due to its medicinal properties and nutritional values. In the present study, Jin Er basidiocarps were often found to be surrounded by Stereum hirsutum fruiting bodies in their natural habitat and occasionally in artificial cultivation. The observation of two different kinds of mycelia within the hymenium and analyses of ITS sequences confirmed that Jin Er basidiocarps were composed of two fungal species, Naematelia aurantialba and S. hirsutum. This heterogeneity of Jin Er fruiting bodies is indeed distinct from the homogeneous hypha of Tremella fuciformis found in Yin Er mushroom, although its development also requires the presence of another fungus Annulohypoxylon stygium. Basidiospores can germinate on the surface of basidiocarps and produce mycelia. However, basidiospores in PDA medium can only bud into yeast-like conidia. The yeast-like conidia of N. aurantialba can transform into pseudohyphae with a change in temperature from 20 °C to 28 °C or switch into filamentous cells on an induction medium (IDM) at 20 °C, 25 °C and 28 °C. This dimorphic was reported for the first time in N. aurantialba. Haustorium-like structures were abundantly observed both within the hymenium and in the aerial mycelia cultured on the IDM. The developmental process was documented firstly in this study, involving the formation of protuberances with basal clamp connections, elongation at the protuberances, branch production, and eventual maturation. However, further observation is required to determine whether the haustorium-like structures can penetrate S. hirsutum hyphae. These findings are expected to provide valuable insights into the relationship and interaction between these two fungi, thereby advancing the cultivation of fruiting bodies.

Mechanical and bio-tribological behaviours of UHMWPE based composites for prosthetic hip joint implant application

Ultra-High Molecular Weight Polyethylene (UHMWPE) composites reinforced with talc, graphite (GRP), and multi-walled carbon nanotubes (MWCNTs) were evaluated for their physical, mechanical, and bio-tribological performances for their application as acetabular liner material for prosthetic hip implant. Addition of 15 wt% of talc to UHMWPE reduced its friction coefficient and wear by approximately 30 % and 54 %, respectively. The addition of 0.5 wt% of MWCNT increased the coefficient of friction by about 6 % with drastic reduction in the wear (∼ 45 %). Hardness and elastic modulus were higher for the composites. Wear mechanism involved plastic deformation and the formation of protuberances.

Black Crust Complex: Influence of Temperature and Period of Wetness on the Development of Fungi in Hevea brasiliensis.

The objective of this work was to evaluate the development of Davidiella sp. and its asexual form, Cladosporium sp., under different environmental conditions in the rubber tree (Hevea brasiliensis). Rubber tree leaves were inoculated with a spore suspension and kept in a humid chamber under different temperatures and wetness periods. The behavior of the fungi was evaluated using a scanning electron microscope (SEM) and an ultraviolet light microscope (UV). In the images obtained in SEM, four hours after inoculation of the fungus, it was possible to verify the germination and penetration of conidia at temperatures of 10 to 20 °C. The formation of conidiophores was verified from six hours after inoculation, indicating that it is in the reproductive period. In the sexual phase, in SEM, from four hours after inoculation, it was possible to verify the formation of small protuberances at temperatures between 10 and 20 °C. These black dots evolve into circular, protruding black spots, like the symptoms of black crust, with apparent spore formation on them. The data obtained from the UV analyses corroborate those from SEM, showing that the fungus has good development in its two phases between temperatures of 20 and 25 °C and that the period of wetness on the leaf can contribute to the initial development of the pathogen.

Salmonella exploits membrane reservoirs for invasion of host cells

Salmonella utilizes a type 3 secretion system to translocate virulence proteins (effectors) into host cells during infection1. The effectors modulate host cell machinery to drive uptake of the bacteria into vacuoles, where they can establish an intracellular replicative niche. A remarkable feature of Salmonella invasion is the formation of actin-rich protuberances (ruffles) on the host cell surface that contribute to bacterial uptake. However, the membrane source for ruffle formation and how these bacteria regulate membrane mobilization within host cells remains unclear. Here, we show that Salmonella exploits membrane reservoirs for the generation of invasion ruffles. The reservoirs are pre-existing tubular compartments associated with the plasma membrane (PM) and are formed through the activity of RAB10 GTPase. Under normal growth conditions, membrane reservoirs contribute to PM homeostasis and are preloaded with the exocyst subunit EXOC2. During Salmonella invasion, the bacterial effectors SipC, SopE2, and SopB recruit exocyst subunits from membrane reservoirs and other cellular compartments, thereby allowing exocyst complex assembly and membrane delivery required for bacterial uptake. Our findings reveal an important role for RAB10 in the establishment of membrane reservoirs and the mechanisms by which Salmonella can exploit these compartments during host cell invasion.

The effects of feedback control parameters on the formation of protuberances in poly(methyl methacrylate) by dynamic plowing lithography

In this study, nanoscale protuberances were fabricated on poly(methyl methacrylate) (PMMA) thin-film surface by mechanical scanning probe lithography, namely dynamic plowing lithography (DPL). However, the formation mechanism of protuberances by DPL remains unclear. Therefore, this paper investigated the formation mechanism and fine control of the protuberances. Considering the influence of the dynamic response of the probe cantilever, proportional gain and integral gain were investigated when the tip scratched PMMA film in scan mode. Using feedback loop control, the increased depth of the groove at the beginning was attributed to the peak of the oscillation amplitude caused by the interplay between lithography and feedback. The cantilever vibrated dramatically when integral gain was increased. When the integral gain was increased to 5, the machined depth was approximately 82 nm, which exposed the substrate. Furthermore, the machined depth depended on the proportional gain when the integral gain was 0. The increased steady-state error that occurred at decreased proportional gain caused the tip to penetrate the sample deeper. In addition, the volume of the pile-up was larger than the removed material. And the material pile-up contributed to the fabrication of the protuberance. Finally, uniform and reliable protuberances were fabricated without proportional gain and integral gain.

Keratinocyte Response to Infection with Sporothrix schenckii.

Sporotrichosis is a subacute, or chronic mycosis caused by traumatic inoculation of material contaminated with the fungus Sporothrix schenckii which is part of the Sporothrix spp. complex. The infection is limited to the skin, although its progression to more severe systemic or disseminated forms remains possible. Skin is the tissue that comes into contact with Sporothrix first, and the role of various cell lines has been described with regard to infection control. However, there is little information on the response of keratinocytes. In this study, we used the human keratinocyte cell line (HaCaT) and evaluated different aspects of infection from modifications in the cytoskeleton to the expression of molecules of the innate response during infection with conidia and yeast cells of Sporothrix schenckii. We found that during infection with both phases of the fungus, alterations of the actin cytoskeleton, formation of membrane protuberances, and loss of stress fibers were induced. We also observed an overexpression of the surface receptors MR, TLR6, CR3 and TLR2. Cytokine analysis showed that both phases of the fungus induced the production of elevated levels of the chemokines MCP-1 and IL-8, and proinflammatory cytokines IFN-α, IFN-γ and IL-6. In contrast, TNF-α production was significant only with conidial infection. In late post-infection, cytokine production was observed with immunoregulatory activity, IL-10, and growth factors, G-CSF and GM-CSF. In conclusion, infection of keratinocytes with conidia and yeast cells of Sporothrix schenckii induces an inflammatory response and rearrangements of the cytoskeleton.

Appearance of phenotypic plasticity of leaves in psammophyte Corynephorus canescens during flooding

The results of the study of the leaf structure in psammophyte Corynephorus canescens, which grew under controlled conditions and flooding using the methods of light microscopy, scanning electron microscopy, and laser confocal microscopy, are presented. This study revealed common and distinctive signs of morphological and anatomical parameters of C. canescens leaves in the phase of vegetative growth. Among the common features were the shape and size of the leaf laminas, hypostomatic type of the leaf, isolateral structure of the parenchyma, the thick-walled epidermis, and the bilayered hypodermis. Among the distinctive features were the signs of the destruction of cells in the photosynthetic parenchyma, change in their shape with the formation of protuberances at the cells’ poles, and almost doubling area of the aerenchyma in C. canescens leaves under flooding conditions. Scanning electron microscopy showed the similarity of ultrastructure and density of trichomes on the adaxial surface, excepting the formation of cuticular wax structures on the epidermal surface of the leaves in flooded plants. The subcellular localization of silicon inclusions was studied for the first time. The presence of amorphous and small crystalline silicon inclusions in the periclinal walls of the main epidermal cells and amorphous silicon inclusions in leaf trichomes was established. An increase in the relative silicon content along the trichomes in the leaves’ epidermis after flooding was revealed. It was assumed that the phenotypic plasticity of C. canescens, is realized through the increasing area of aerenchyma in leaves and increasing silicon content in trichomes. Such plasticity helps to optimize both the oxygen balance of plants and water balance in flooded plants, thus increasing the species’ resistance to prolonged flooding.

Graphene as regulating zinc deposition layer for long-life zinc ion hybrid supercapacitors

Zinc ion hybrid supercapacitors (ZIHS) are promising aqueous energy storage devices due to their low-cost and excellent long cyclic stability. However, the poor stability caused by growth of zinc (Zn) dendrite due to Zn uneven deposition/stripping, which limits the applications of ZIHS. Hence, graphene is constructed as surface layer of Zn foil to inhibit the formation of protuberances and improve the cycle life of ZIHS. Moreover, the cyclic life of graphene@Zn anode in ZIHS at 1 A g−1 reaches at least 10,000 cycles, 200-fold higher than that of Zn foil anode. The ultra-long life of graphene@Zn electrode is attributed to abundant active sites on graphene for Zn2+ nucleation and subsequently uniform deposition. Importantly, graphene layers not only inhibit dendrites by guiding uniform Zn deposition, but also reduce the side-reactions by blocking the electrolyte. Overall, the proposed method to improve reversibility and cyclic stability of Zn anode looks promising for the development of large-scale ZIHS.

Mouse Astrocytes Promote Microglial Ramification by Releasing TGF-β and Forming Glial Fibers.

The morphology of microglial cells is often closely related to their functions. The mechanisms that regulate microglial ramification are not well understood. Here we reveal the biological mechanisms by which astrocytes regulate microglial ramification. Morphological variation in mouse microglial cultures was measured in terms of cell area as well as branch number and length. Effects on microglial ramification were analyzed after microinjecting the toxin L-alpha-aminoadipic acid (L-AAA) in the mouse cortex or hippocampus to ablate astrocytes, and after culturing microglia on their own in an astrocyte-conditioned medium (ACM) or together with astrocytes in coculture. TGF-β expression was determined by Western blotting, immunohistochemistry, and ELISA. The TGF-β signaling pathway was blocked by the TGF-β antibody to assess the role of TGF-β on microglial ramification. The results showed that microglia had more and longer branches and smaller cell bodies in brain areas where astrocytes were abundant. In the mouse cortex and hippocampus, ablation of astrocytes by L-AAA decreased number and length of microglial branches and increased the size of cell bodies. Similar results were obtained with isolated microglia in culture. However, isolated microglia were able to maintain their multibranched structure for a long time when cultured on astrocyte monolayers. Ameboid microglia isolated from P0 to P3 mice showed increased ramification when cultured in ACM or on astrocyte monolayers. Microglia cultured on astrocyte monolayers showed more complex branching structures than those cultured in ACM. Blocking astrocyte-derived TGF-β decreased microglial ramification. Astrocytes induced the formation of protuberances on branches of microglia by forming glial fibers that increased traction. These experiments in mice suggest that astrocytes promote microglial ramification by forming glial fibers to create traction and by secreting soluble factors into the surroundings. For example, astrocyte-secreted TGF-β promotes microglia to generate primitive branches, whose ramification is refined by glial fibers.

Ionic stress induces fusion of mitochondria to 3-D networks: An electron tomography study.

Mitochondria are central organelles for energy supply of cells and play an important role in maintenance of ionic balance. Consequently mitochondria are highly sensitive to any kind of stress to which they mainly response by disturbance of respiration, ROS production and release of cytochrome c into the cytoplasm. Many of the physiological and molecular stress reactions of mitochondria are well known, yet there is a lack of information on corresponding stress induced structural changes. 3-D visualization of high-pressure frozen cells by FIB-SEM tomography and TEM tomography as used for the present investigation provide an excellent tool for studying structure related mitochondrial stress reactions. In the present study it is shown that mitochondria in the unicellular fresh-water algal model system Micrasterias as well as in the closely related aquatic higher plant Lemna fuse to local networks as a consequence of exposure to ionic stress induced by addition of KCl, NaCl and CoCl2. In dependence on concentration and duration of the treatment, fusion of mitochondria occurs either by formation of protuberances arising from the outer mitochondrial membrane, or by direct contact of the surface of elongated mitochondria. As our results show that respiration is maintained in both model systems during ionic stress and mitochondrial fusion, as well as formation of protuberances are reversible, we assume that mitochondrial fusion is a ubiquitous process that may help the cells to cope with stress. This may occur by interconnecting the respiratory chains of the individual mitochondria and by enhancing the buffer capacity against stress induced ionic imbalance.

Application of ultrasound modified corn straw as adsorbent for malachite green removal from synthetic and real effluents.

This work aimed to study the removal of malachite green dye from wastewaters through adsorption using raw corn straw (RCS) and ultrasound-assisted modified corn straw (MCS). RCS and MCS were prepared and characterized in detail. The characterization indicated that RCS and MCS presented favorable structures for malachite green adsorption and that the ultrasound treatment provided a disorganization of the adsorbent's crystalline regions and also caused the formation of cavities and protuberances. The adsorption study was performed by equilibrium isotherms, kinetic curves, thermodynamic parameters, and application in real effluents composed of dye mixtures and inorganic compounds. The Elovich model was suitable for the adsorption kinetics and the Freundlich model was appropriate to represent the equilibrium. The maximum experimental adsorption capacities were 200mgg-1 for RCS and 210mgg-1 for MCS, obtained at 328K. MCS was more effective than RCS to treat real effluents, attaining around 92% of color removal.

Effect of Contact Area on the Wear and Friction of UHMWPE in Circular Translation Pin-on-Disk Tests

Circular translation pin-on-disk (CTPOD) tests were performed for ultrahigh molecular weight polyethylene (UHMWPE) with a view to reproducing wear mechanisms that prevail in total hip prostheses. The contact surface diameter varied from 3.0 mm to 30 mm, while the slide track diameter was fixed, 10 mm. The counterface was polished CoCr, and the lubricant was diluted alpha calf serum. Either the nominal contact pressure (1.1 MPa) or the load (126 N) was kept constant. With a constant contact pressure, the wear factor decreased steeply when the contact diameter exceeded the slide track diameter, apparently because the wear debris was not readily conveyed away from the contact. With constant load, both the wear factor and the coefficient of friction increased linearly with increasing contact area. This trend was in agreement with clinical observations that the wear rate of UHMWPE acetabular cups increased with increasing femoral head size. With nominal contact pressures approaching 10 MPa however, the bearing surface topography markedly differed from clinical observations. This was probably due to overheating of the contact and plastic deformation that resulted in the formation of protuberances not seen clinically. The present study emphasized the importance of test parameters in the pin-on-disk wear screening of prosthetic joint materials. It appeared that the contact surface diameter of the flat-on-flat test should be below the slide track diameter, and that the nominal contact pressure should be of the order of 1 MPa.

The mechanism of generating nanoporous Au by de-alloying amorphous alloys

De-alloying, i.e. selective dissolution of alloys, is currently studied to produce nanoporous gold items suited for use in catalysis, electrochemical applications, sensors and actuators. Both crystalline and amorphous alloys can be selectively etched. In the former, less noble atoms are removed from surface terraces of grains layer by layer, while noble ones form mounds. These evolve by undercutting and electrolyte percolation to form a ligament network. The mechanism of ligament development by de-alloying amorphous alloys is unknown. Here we show that for de-alloying a Au-based glass, in this case Au40Cu28Ag7Pd5Si20, percolation of the electrolyte through cracks of the native surface oxide initiates the formation of protuberances which are soon undercut. An interlayer develops, where Au crystals germinate, grow to nanometer size by diffusion and impinge. This is how ligaments start to coarsen. The interlayer is found at all stages between coarsened ligaments and amorphous phase. The ligaments are defective polycrystals, as opposed to single crystals obtained from crystalline alloys.

Structural and electrical properties of tracks of heavy ions in polyethylene terephthalate and mica

An image of the entrance of high-energy ions of krypton, xenon, and bismuth on the surface of polyethylene terephthalate (PET) and mica is obtained. It is shown that in both cases the tracks have the appearance of protuberances. The formation of protuberances is associated with the destruction of material in the region of the track, the formation of amorphous structure, and the removal of low-molecular-weight radiolysis products as gaseous substances. Storage of the irradiated PET samples in water and a weak alkaline solution for several hours changes the surface topography due to hydrolysis of the material and the removal of radiolysis products into the solution. The kinetics of etching tracks in a weak alkaline solution and the formation of pores are studied. The stream function, electrical resistance, and permeability of the tracks in KCl, LiCl, MgCl2, and BaCl2 electrolytes are measured. The surface charge of the tracks is calculated from these values.

Structural and electric surface characteristics of heavy ion tracks in poly(ethylene terephthalate) and mica

The entry of high-energy Kr, Xe, and Bi ions into the surface of poly(ethylene terephthalate) (PET) and mica has been imaged. It has been shown that the track images have the shape of protuberances in both cases. The formation of protuberances is associated with the degradation of the material in the track region, in the formation of an amorphous structure, and the release of low-molecular radiolysis products as gaseous compounds. Holding the irradiated PET samples in water and dilute alkaline solution for several hours changes the surface topography due to hydrolysis of the material and escape of the radiolysis products to the solution. The kinetics of track etching in the dilute alkaline solution and pore formation have been studied. The electrical resistance and the permeability of the tracks in KCl, LiCl, MgCl2, and BaCl2 electrolytes have been measured.

Robust Polypropylene Fabrics Super-Repelling Various Liquids: A Simple, Rapid and Scalable Fabrication Method by Solvent Swelling.

A simple, rapid (10 s) and scalable method to fabricate superhydrophobic polypropylene (PP) fabrics is developed by swelling the fabrics in cyclohexane/heptane mixture at 80 °C. The recrystallization of the swollen macromolecules on the fiber surface contributes to the formation of submicron protuberances, which increase the surface roughness dramatically and result in superhydrophobic behavior. The superhydrophobic PP fabrics possess excellent repellency to blood, urine, milk, coffee, and other common liquids, and show good durability and robustness, such as remarkable resistances to water penetration, abrasion, acidic/alkaline solution, and boiling water. The excellent comprehensive performance of the superhydrophobic PP fabrics indicates their potential applications as oil/water separation materials, protective garments, diaper pads, or other medical and health supplies. This simple, fast and low cost method operating at a relatively low temperature is superior to other reported techniques for fabricating superhydrophobic PP materials as far as large scale manufacturing is considered. Moreover, the proposed method is applicable for preparing superhydrophobic PP films and sheets as well.

Histochemical evaluation of induction of somatic embryogenesis in Passiflora edulis Sims (Passifloraceae)

The aim of this study was to describe the accumulation of reserves during the somatic embryogenesis process in Passiflora edulis Sims FB-300, obtained from mature zygotic embryos, using histochemical methods. Mature zygotic embryos were inoculated in Murashige and Skoog induction media supplemented with 31.06 μM of picloram, 2.22 μM of benzyladenine, and 2.27 μM of thidiazuron. The zygotic embryo explants, at different developmental stages, were collected and fixed in Karnovsky solution and subsequently subjected to dehydration in an ethanol series and embedded in acrylic resin. Transverse and longitudinal sections (5-μm thick) were stained with toluidine blue for anatomical characterization, using Xylidine Ponceau for the detection of total protein, periodic acid-Schiff reagent for neutral polysaccharides, Sudan black B to detect lipids, and Lugol’s reagent for the starch detection. Histological sections revealed the formation of protuberances and globular stage somatic embryos in the cotyledonary region of the zygotic embryo. Histochemical tests revealed the presence of large quantities of protein bodies in zygotic embryos of P. edulis, which were gradually metabolized during somatic embryo development. Lipid bodies and starch grains were identified only after 20 d of culture, suggesting the use of these compounds as energy source for de novo synthesis. The present study describes the anatomical changes and the pattern of reserve accumulation during the somatic embryogenesis process in P. edulis.

Evaluation of protuberance and groove formation in extremely thin DLC films on Si substrates due to diamond tip sliding by atomic force microscopy

In order to enable higher density recording, a better understanding of the magnetic disk/head interface is required. Therefore, the nanowear properties of extremely thin diamond-like carbon (DLC) films deposited on a Si(100) surface via filtered cathodic vacuum arc (FCVA) and electron cyclotron resonance-chemical vapor deposition (ECR-CVD) methods were evaluated using atomic force microscopy. It is proposed that tribochemical reactions led to the formation of protuberances on the thin DLC films coated on Si substrates. However, the FCVA-DLC films were more resistant to these tribochemical reactions of Si than the ECR-CVD-DLC films. For both 1.5-nm-thick ECR-CVD-DLC and 0.8-nm-thick FCVA-DLC films, the film was removed even at low loads, and the protuberances increased with the load because of direct contact between the diamond tip and the Si surface. Diamond tip sliding at higher loads also removed thicker ECR-CVD-DLC films, while thicker FCVA-DLC films remained on the Si surface and prevented tribochemical reactions. Furthermore, thicker ECR-CVD-DLC films exhibited deeper wear depths than FCVA-DLC films. These results reveal the differences in the resistance to wear and tribochemical reactions of extremely thin DLC films prepared using different deposition methods and confirm the superior properties of FCVA-DLC films.

Morphology and Properties of Polypropylene Blends Containing Phenolic Resin Produced from the Liquefaction of Empty Fruit Bunch Fibres

Phenol formaldehyde (PF) resin prepared from phenol-liquefied empty fruit bunch (EFB) fibres was blended with polypropylene (PP) using a co-rotating twin-screw extruder. The effects of the PF content (10, 20, 30 and 40 wt.%) blended with PP on the properties of the PP/PF board were investigated. SEM images depicted the formation of spherical protuberances and voids in the PP/PF board with the increasing PF content. The size of the protuberances was also increased with the PF content. The formation of void could be due to the release of water, ammonia and formaldehyde during the blending and hot-press processes. The density, moisture content and maximum water absorption of the PP/PF board increased with the increase of PF content. The TG curves of the PP/PF boards revealed that the PF and PP in the PP/PF board decomposed at different temperature ranges, i.e., 200–420 and 425–480 °C, respectively. The addition of PF to PP reduced the activation energy of the first stage thermal decomposition of the PP/PF boards. The addition of 10 wt.% PF was the optimum content to produce PP/PF board with optimum mechanical properties.

Scratch direction and threshold force in nanoscale scratching using atomic force microscopes

The nanoscaled tip in an AFM (atomic force microscope) has become an effective scratching tool for material removing in nanofabrication. In this article, the characteristics of using a diamond-coated pyramidal tip to scratch Ni–Fe thin film surfaces was experimentally investigated with the focus on the evaluation of the influence of the scratch or scan direction on the final shape of the scratched geometry as well as the applied scratch force. Results indicated that both the scratched profile and the scratch force were greatly affected by the scratch direction. It has been found that, to minimize the formation of protuberances along the groove sides and to have a better control of the scratched geometry, the tip face should be perpendicular to the scratching direction, which is also known as orthogonal cutting condition. To demonstrate the present findings, three groove patterns have been scratched with the tip face perpendicular to the scratching direction and very little amount of protuberances was observed. The threshold scratch force was also predicted based on the Hertz contact theory. Without considering the surface friction and adhesive forces between the tip and substrate, the threshold force predicted was twice smaller than the measurement value. Finally, recommendations for technical improvement and research focuses are provided.