Cellular organization and fine structure of type II microtrich sensilla in gammaridean amphipods (Crustacea)

1999 ◽  
Vol 77 (1) ◽  
pp. 88-107 ◽  
Author(s):  
V J Steele ◽  
D H Steele
Keyword(s):  
Sensory Neurons ◽  
Sensory Cell ◽  
Cell Process ◽  
Outer Cell ◽  
Type Ii ◽  
Cellular Organization ◽  
Insect Sensilla ◽  
Transmission Electron ◽  
Cell Processes ◽  
Tormogen Cell

The cellular organization of type II microtrich sensilla was studied in male Anonyx lilljeborgi Boeck, 1871 (Lysianassoidea) by light and transmission electron microscopy. The sensillum consists of two bipolar sensory neurons and three concentric sheath cells. The sensory cell bodies are subepidermal. In each sensillum both dendrites are enclosed by the thecogen cell process. The inner dendritic segments are filled with mitochondria and lucent vesicles and expand in the epidermis into a spindle-shaped swelling. One of the neurons gives rise to two cilia and the second to a single cilium. These three outer dendritic segments lie in the receptorlymph cavity. The dendritic sheath, secreted by the thecogen cell process, completely ensheaths the outer dendritic segments. The trichogen (middle) cell and the tormogen (outer) cell incompletely enclose the thecogen cell, but their processes form autojunctions around the dendritic sheath in the apical epidermis. In premolt, the trichogen cell processes project into the exuvial space. The cytoplasm of the tormogen cell and the bordering epidermal cells contains coarse osmiophilic inclusions. All the cells of the sensillum are joined by desmosomes. The sensilla structurally resemble chemosensory (gustatory) insect sensilla.

scholarly journals Genetically modified human type II collagen for N- and C-terminal covalent tagging

2018 ◽  
Vol 96 (2) ◽  
pp. 204-211
Author(s):  
Andrew Wieczorek ◽  
Clara K. Chan ◽  
Suzana Kovacic ◽  
Cindy Li ◽  
Thomas Dierks ◽  
...  
Keyword(s):  
Developmental Disorders ◽  
Connective Tissue Diseases ◽  
Sulfhydryl Group ◽  
Type Ii Collagen ◽  
Type Ii ◽  
Structural Protein ◽  
Connective Tissues ◽  
Human Type ◽  
C Terminus ◽  
Transmission Electron

Collagen is the predominant structural protein in vertebrates, where it contributes to connective tissues and the ECM; it is also widely used in biomaterials and tissue engineering. Dysfunction of this protein and its processing can lead to a wide variety of developmental disorders and connective tissue diseases. Recombinantly engineering the protein is challenging due to post-translational modifications generally required for its stability and secretion from cells. Introducing end labels into the protein is problematic, because the N- and C-termini of the physiologically relevant tropocollagen lie internal to the initially flanking N- and C-propeptide sequences. Here, we introduce mutations into human type II procollagen in a manner that addresses these concerns and purify the recombinant protein from a stably transfected HT1080 human fibrosarcoma cell line. Our approach introduces chemically addressable groups into the N- and C-telopeptide termini of tropocollagen. Simultaneous overexpression of formylglycine generating enzyme (FGE) allows the endogenous production of an aldehyde tag in a defined, substituted sequence in the N terminus of the mutated collagen, whereas the C-terminus of each chain presents a sulfhydryl group from an introduced cysteine. These modifications are designed to enable specific covalent end-labelling of collagen. We find that the doubly mutated protein folds and is secreted from cells. Higher order assembly into well-ordered collagen fibrils is demonstrated through transmission electron microscopy. Chemical tagging of thiols is successful; however, background from endogenous aldehydes present in wild-type collagen has thus far obscured the desired specific N-terminal labelling. Strategies to overcome this challenge are proposed.

Type II Dislocation Loops and their Effect on Strain in Ion Implanted Silicon as Studied by High Resolution X-ray Diffraction

1995 ◽  
Vol 378 ◽  
Author(s):  
R. H. Thompson ◽  
V. Krishnamoorthy ◽  
J. Liu ◽  
K. S. Jones
Keyword(s):  
High Resolution ◽  
Type Ii ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
Empirical Constant ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Measured Strain ◽  
P Type

AbstractP-type (100) silicon wafers were implanted with 28Si+ ions at an energy of 50 keV and to doses of 1 × 1015, 5 × 1015 and 1 × 1016 cm−2, respectively, and annealed in a N2 ambient at temperatures ranging from 700°C to 1000°C for times ranging from 15 minutes to 16 hours. The resulting microstructure consisted of varying distributions of Type II end of range dislocation loops. The size distribution of these loops was quantified using plan-view transmission electron microscopy and the strain arising from these loops was investigated using high resolution x-ray diffraction. The measured strain values were found to be constant in the loop coarsening regime wherein the number of atoms bound by the loops remained a constant. Therefore, an empirical constant of 7.7 × 10−12 interstitial/ppm of strain was evaluated to relate the number of interstitials bound by these dislocation loops and the strain. This value was used successfully in estimating the number of interstitials bound by loops at the various doses studied provided the annealing conditions were such that the loop microstructure was in the coarsening or dissolution regime.

scholarly journals Effect of surface pretreatment of TiO 2 films on interfacial processes leading to bacterial inactivation in the dark and under light irradiation

2015 ◽  
Vol 5 (1) ◽  
pp. 20140046 ◽  
Author(s):  
Sami Rtimi ◽  
Jelena Nesic ◽  
Cesar Pulgarin ◽  
Rosendo Sanjines ◽  
Michael Bensimon ◽  
...  
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Bond Distance ◽  
Light Irradiation ◽  
Outer Cell ◽  
Bacterial Inactivation ◽  
Surface Pretreatment ◽  
X Ray ◽  
E Coli ◽  
Transmission Electron ◽  
Plasma Pretreatment

Evidence is presented for radio-frequency plasma pretreatment enhancing the amount and adhesion of TiO 2 sputtered on polyester (PES) and on polyethylene (PE) films. Pretreatment is necessary to attain a suitable TiO 2 loading leading to an acceptable Escherichia coli reduction kinetics in the dark or under light irradiation for PES–TiO 2 and PE–TiO 2 samples. The amount of TiO 2 on the films was monitored by diffuse reflectance spectroscopy and X-ray fluorescence. X-ray electron spectroscopy shows the lack of accumulation of bacterial residues such as C, N and S during bacterial inactivation since they seem to be rapidly destroyed by TiO 2 photocatalysis. Evidence was found for Ti 4+ /Ti 3+ redox catalysis occurring on PES–TiO 2 and PE–TiO 2 during the bacterial inactivation process. On PE–TiO 2 surfaces, Fourier transform infrared spectroscopy (ATR-FTIR) provides evidence for a systematic shift of the n a (CH 2 ) stretching vibrations preceding bacterial inactivation within 60 min. The discontinuous IR-peak shifts reflect the increase in the C–H inter-bond distance leading to bond scission. The mechanism leading to E. coli loss of viability on PES–TiO 2 was investigated in the dark up to complete bacterial inactivation by monitoring the damage in the bacterial outer cell by transmission electron microscopy. After 30 min, the critical step during the E. coli inactivation commences for dark disinfection on 0.1–5% wt PES–TiO 2 samples. The interactions between the TiO 2 aggregates and the outer lipopolysaccharide cell wall involve electrostatic effects competing with the van der Waals forces.

scholarly journals FINE STRUCTURE OF THE EYE OF A CHAETOGNATH

1964 ◽  
Vol 21 (1) ◽  
pp. 115-132 ◽  
Author(s):  
Richard M. Eakin ◽  
Jane A. Westfall
Keyword(s):  
Fine Structure ◽  
Photoreceptor Cell ◽  
Sensory Cell ◽  
Pigment Cell ◽  
Evolutionary Relationship ◽  
Cell Process ◽  
Rods And Cones ◽  
Fine Structure And Function ◽  
And Function ◽  
Relationship Of

Electron microscopy reveals a star-like pigment cell at the center of the eye of the arrow-worm, Sagitta scrippsae. Between the arms of the pigment cell are clusters of photoreceptor cell processes, each process consisting of: (1) a tubular segment containing longitudinally arranged microtubules about 500 A in diameter and 20 µ in length; (2) a remarkable conical body, composed of cords and large granules, situated at the base of the tubular segment; and (3) a connecting piece which, like that of rods and cones, connects the process with the sensory cell proper and through which runs a fibrillar apparatus consisting of nine peripheral double tubules. Beneath the connecting piece lies a typical centriole with a striated rootlet. The receptor cell process is deeply recessed into the sensory cell which may possess a corona of microvilli at its inner surface. A nerve fiber arises from the outer end of the cell and passes into the optic nerve. Additional features are some supporting cells, an external layer of flattened epithelial cells, and an over-all investment of basement membrane and thick fibrous capsule. The fine structure and function of these elements of the eye are discussed in relation to earlier studies with the light microscope. The ciliary nature of the photoreceptor cell process in S. scrippsae points to a probable evolutionary relationship of chaetognaths to echinoderms and chordates.

scholarly journals Morphologic Damage of Rat Alveolar Epithelial Type II Cells Induced by Bile Acids Could Be Ameliorated by Farnesoid X Receptor Inhibitor Z-Guggulsterone In Vitro

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jieqin Wang ◽  
Yaowei Huang ◽  
Xusheng Hou ◽  
Wenyu Wu ◽  
Lei Nie ◽  
...  
Keyword(s):  
Bile Acids ◽  
Farnesoid X Receptor ◽  
Ultrastructural Changes ◽  
Respiratory Disorder ◽  
Type Ii Cells ◽  
Type Ii ◽  
Alveolar Epithelial ◽  
Transmission Electron ◽  
High Level

Objective. To determine whether bile acids (BAs) affect respiratory functions through the farnesoid X receptor (FXR) expressed in the lungs and to explore the possible mechanisms of BAs-induced respiratory disorder.Methods. Primary cultured alveolar epithelial type II cells (AECIIs) of rat were treated with different concentrations of chenodeoxycholic acid (CDCA) in the presence or absence of FXR inhibitor Z-guggulsterone (GS). Then, expression of FXR in nuclei of AECIIs was assessed by immunofluorescence microscopy. And ultrastructural changes of the cells were observed under transmission electron microscope and analyzed by Image-Pro Plus software.Results. Morphologic damage of AECIIs was exhibited in high BAs group in vitro, with high-level expression of FXR, while FXR inhibitor GS could attenuate the cytotoxicity of BAs to AECIIs.Conclusions. FXR expression was related to the morphologic damage of AECIIs induced by BAs, thus influencing respiratory functions.

Point Defect Detector Studies of Ge+ Implanted Silicon upon Oxidation

1992 ◽  
Vol 262 ◽  
Author(s):  
H. L. Meng ◽  
S. Prusstn ◽  
K. S. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Point Defect ◽  
Point Defects ◽  
Type Ii ◽  
Dislocation Loops ◽  
Furnace Annealing ◽  
Plan View ◽  
Atom Concentration ◽  
Transmission Electron

ABSTRACTPrevious results [1] have shown that type II (end-of-range) dislocation loops can be used as point defect detectors and are efficient in measuring oxidation induced point defects. This study investigates the interaction between oxidation-induced point defects and dislocation loops when Ge+ implantation was used to form the type II dislocation loops. The type II dislocation loops were introduced via Ge+ implants into <100> Si wafers at 100 keV to at doses ranging from 2×1015 to l×1016/cm2. The subsequent furnace annealing at 900 °C was done for times between 30 min and 4 hr in either a dry oxygen or nitrogen ambient. The change in atom concentration bound by dislocation loops as a result of oxidation was measured by plan-view transmission electron microscopy (PTEM). The results show that the oxidation rate for Ge implanted Si is similar to Si+ implanted Si. Upon oxidation a decrease in the interstitial injection was observed for the Ge implanted samples relative to the Si implanted samples. With increasing Ge+ dose the trapped atom concentration bound by the loops actually decreases upon oxidation relative to the inert ambient implying oxidation of Ge+ implanted silicon can result in either vacancy injection or the formation of an interstitial sink.

Protoplast Formation from Submerged Mycelium and from Spore Germinants of Streptomyces coelicolor

1985 ◽  
Vol 38 (1) ◽  
pp. 175 ◽  
Author(s):  
I Stevenson
Keyword(s):  
Cell Wall ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Streptomyces Coelicolor ◽  
Cross Wall ◽  
Cellular Organization ◽  
Protoplast Formation ◽  
Cellular Compartment ◽  
Transmission Electron ◽  
Single Region

Stages in the formation of protoplasts from S. coelicolor strain A3(2) have been studied by transmission electron microscopy. Protoplasts liberated from submerged mycelial growth were variable in size and were released when digestion of the cell wall by lysozyme had completely or almost completely taken place. Protoplasts did not fully adopt the typical rounded shape until after release. A single region of cytoplasm gave rise to more than one protoplast unit. Protoplasts released from spore germinants escaped from the tip of the germ tube, which was the region of the cell wall most susceptible to digestion. Protoplasts derived from spore germinants were more consistent in size and rounded up more rapidly. If a cross-wall had formed in a germinant then it gave rise to separate protoplasts from each cellular. compartment. Protoplasts of either type contained a single DNA region. These studies give an indication of the cellular organization of a streptomycete colony, which can be visualized as a multinucleated assemblage of cellular units in a common cytoplasm. The assembly of units separates into a number of protoplasts on digestion of the cell wall.

Characterization of mammary cells from the lactating rat by electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 560-561
Author(s):  
P. Sadhukhan ◽  
J. Chakraborty ◽  
M. S. Soloff ◽  
M. H. Wieder ◽  
D. Senitzer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Types ◽  
Myoepithelial Cells ◽  
Mammary Tissue ◽  
Secretory Cells ◽  
Isolated Cells ◽  
Transmission Electron ◽  
Cell Processes ◽  
Phosphatase Cytochemistry

The means to identify cells isolated from the mammary gland of the lactating rat as a prerequisite for cell purification have been developed.The cells were isolated from mammary tissue with 0. 1% collagenase, and they were visualized by scanning and transmission electron microscopy and by alkaline phosphatase cytochemistry.The milk-secreting cells have surface microvilli, whereas the surface of the myoepithelial cells is smooth (Fig. 1). The two isolated epithelial cell types are readily distinguishable by transmission electron microscopy (Fig. 2). The secretory cells contain vacuoles and a relatively extensive rough endoplasmic reticulum, whereas the myoepithelial cells contain a more osmiophilic cytoplasm, contractile filaments (Fig. 3) and elongate processes. These features are consistent with the appearance of the two cell types in situ.Incubation of isolated cells with oxytocin prior to glutaraldehyde fixation resulted in the contraction of the myoepithelial cell processes (Figs. 4 & 5). This physiological response to oxytocin shows that the isolated myoepithelial cells were intact. The appearance of isolated secretory cells was unchanged by the presence of oxytocin.

Identification and distribution of gap junctions in the mesoderm of the developing chick limb bud

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 99-110
Author(s):  
Robert O. Kelley ◽  
John F. Fallon
Keyword(s):  
Electron Microscopy ◽  
Gap Junctions ◽  
Limb Development ◽  
Freeze Fracture ◽  
Mesenchymal Cells ◽  
Limb Bud ◽  
Metabolic Coupling ◽  
Transmission Electron ◽  
Communicating Junctions ◽  
Cell Processes

Sub-ridge, core, anterior and posterior borders of mesoderm were dissected from stages 22–24 chick wing buds to investigate whether structures for intercellular coupling develop between mesenchymal cells. Fine structure was examined using techniques of transmission electron microscopy, freeze-fracture and scanning electron microscopy. Gap (communicating) junctions which were observed between mesenchymal cells of all limb bud regions were distributed between apposed cell bodies, points of contact between cell processes and other cell bodies, and between contacting tips of slender cell projections. In addition, particularly in the subridge region, filopodia were observed to extend through the intercellular matrix to contact other cells several micrometers distant. The observations reported in this paper show that mesodermal cells throughout the limb have the structural capability for electrotonic and metabolic coupling during a critical period of morphogensisis in the avian limb. Whether intercellular signals which are thought to be transmitted through gap junctions are active in normal limb development remains to be investigated.

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