scholarly journals The effects of plant cysteine proteinases on the nematode cuticle

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Victor S. Njom ◽  
Tim Winks ◽  
Oumu Diallo ◽  
Ann Lowe ◽  
Jerzy Behnke ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Protein Identification ◽  
Cysteine Proteinases ◽  
C Elegans ◽  
Development Of Resistance ◽  
Free Living Nematode ◽  
Nematode Cuticle ◽  
Scanning Electron

Abstract Background Plant-derived cysteine proteinases of the papain family (CPs) attack nematodes by digesting the cuticle, leading to rupture and death of the worm. The nematode cuticle is composed of collagens and cuticlins, but the specific molecular target(s) for the proteinases have yet to be identified. Methods This study followed the course of nematode cuticle disruption using immunohistochemistry, scanning electron microscopy and proteomics, using a free-living nematode, Caenorhabditis elegans and the murine GI nematode Heligmosomoides bakeri (H. polygyrus) as target organisms. Results Immunohistochemistry indicated that DPY-7 collagen is a target for CPs on the cuticle of C. elegans. The time course of loss of DPY-7 from the cuticle allowed us to use it to visualise the process of cuticle disruption. There was a marked difference in the time course of damage to the cuticles of the two species of nematode, with H. bakeri being more rapidly hydrolysed. In general, the CPs’ mode of attack on the nematode cuticle was by degrading the structural proteins, leading to loss of integrity of the cuticle, and finally death of the nematode. Proteomic analysis failed conclusively to identify structural targets for CPs, but preliminary data suggested that COL-87 and CUT-19 may be important targets for the CPs, the digestion of which may contribute to cuticle disruption and death of the worm. Cuticle globin was also identified as a cuticular target. The presence of more than one target protein may slow the development of resistance against this new class of anthelmintic. Conclusions Scanning electron microscopy and immunohistochemistry allowed the process of disruption of the cuticle to be followed with time. Cuticle collagens and cuticlins are molecular targets for plant cysteine proteinases. However, the presence of tyrosine cross-links in nematode cuticle proteins seriously impeded protein identification by proteomic analyses. Multiple cuticle targets exist, probably making resistance to this new anthelmintic slow to develop. Graphic Abstract

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

scholarly journals C. elegans pronuclei fuse after fertilization through a novel membrane structure

2019 ◽  
Vol 219 (2) ◽  
Author(s):  
Mohammad Rahman ◽  
Irene Y. Chang ◽  
Adam Harned ◽  
Richa Maheshwari ◽  
Kwabena Amoateng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Caenorhabditis Elegans ◽  
Membrane Structure ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Nanometer Scale ◽  
C Elegans ◽  
Membrane Region ◽  
Scanning Electron

After fertilization, parental genomes are enclosed in two separate pronuclei. In Caenorhabditis elegans, and possibly other organisms, when the two pronuclei first meet, the parental genomes are separated by four pronuclear membranes. To understand how these membranes are breached to allow merging of parental genomes we used focused ion beam scanning electron microscopy (FIB-SEM) to study the architecture of the pronuclear membranes at nanometer-scale resolution. We find that at metaphase, the interface between the two pronuclei is composed of two membranes perforated by fenestrations ranging from tens of nanometers to several microns in diameter. The parental chromosomes come in contact through one of the large fenestrations. Surrounding this fenestrated, two-membrane region is a novel membrane structure, a three-way sheet junction, where the four membranes of the two pronuclei fuse and become two. In the plk-1 mutant, where parental genomes fail to merge, these junctions are absent, suggesting that three-way sheet junctions are needed for formation of a diploid genome.

scholarly journals Choledocystus elegans (Digenea: Plagiorchiidae) of Leptodactylus paraensis (Amphibia: Leptodactylidae) from the Brazilian Amazon

2017 ◽  
Vol 26 (4) ◽  
pp. 511-515 ◽  
Author(s):  
Tássia Fernanda Furo Gomes ◽  
Francisco Tiago de Vasconcelos Melo ◽  
Elane Guerreiro Giese ◽  
Adriano Penha Furtado ◽  
Jeannie Nascimento dos Santos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Small Intestine ◽  
Brazilian Amazon ◽  
The Body ◽  
Pore Region ◽  
C Elegans ◽  
Morphological Aspects ◽  
First Time ◽  
Scanning Electron

Abstract The trematodes are parasites of the several vertebrates including amphibians, however the knowledge about of the taxonomy these parasites is still confuse. The trematode Choledocystus elegans was found in the small intestine of the Leptodactylus paraensis in eastern Amazon and presents the following characteristics: several pointed tegumentary spines, papillae on the outer and inner edges of the oral and ventral suckers, a round, well-developed cirrus sac, a well-developed cirrus, oblique testicles, a ovary right side, uterine loops extending between the testicles, follicular vitellaria distributed throughout the body, starting at the genital pore region and caeca close the end of the body. For the first time, this study identified C. elegans parasitizing L. paraensis and describes morphological aspects never characterized using light and scanning electron microscopy.

Formation of Metal–Organic Frameworks on a Metal Ion-Doped Polymer Substrate: In-Depth Time-Course Analysis Using Scanning Electron Microscopy

Langmuir ◽  
2019 ◽  
Vol 35 (32) ◽  
pp. 10390-10396 ◽  
Author(s):  
Takaaki Tsuruoka ◽  
Manami Hata ◽  
Shoya Hirao ◽  
Takashi Ohhashi ◽  
Yohei Takashima ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Metal Ion ◽  
Time Course ◽  
Metal Organic Frameworks ◽  
Polymer Substrate ◽  
Metal Organic ◽  
Doped Polymer ◽  
Scanning Electron

scholarly journals Structural analysis of the C. elegans dauer larval anterior sensilla by Focused Ion Beam-Scanning Electron Microscopy

2021 ◽  
Author(s):  
Sebastian Britz ◽  
Sebastian Matthias Markert ◽  
Daniel Witvliet ◽  
Anna Maria Steyer ◽  
Sarah Troeger ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sensory Neurons ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Sensory System ◽  
Beam Scanning ◽  
C Elegans ◽  
Dauer Larvae ◽  
Scanning Electron

At the end of the first larval stage, the nematode Caenorhabditis elegans developing in harsh environmental conditions is able to choose an alternative developmental path called the dauer diapause. Dauer larvae exhibit different physiology and behaviors from non-dauer larvae. Using focused ion beam scanning electron microscopy (FIB-SEM), we volumetrically reconstructed the anterior sensory apparatus of C. elegans dauer larvae with unprecedented precision. We provide a detailed description of some neurons, focusing on structural details that were unknown or unresolved by previously published studies. They include: 1) dauer-specific branches of the IL2 sensory neurons project into the periphery of anterior sensilla and motor or putative sensory neurons at the sub-lateral cords; 2) ciliated endings of URX sensory neurons are supported by both ILso and AMso socket cells near the amphid openings; 3) variability in amphid sensory dendrites among dauers; 4) somatic RIP interneurons maintain their projection into the pharyngeal nervous system. Our results support the notion that dauer larvae structurally expand their sensory system to facilitate searching for more favorable environments.

Recruitment of Labelled Monocytes by Experimental Venous Thrombi

2001 ◽  
Vol 85 (06) ◽  
pp. 1018-1024 ◽  
Author(s):  
C. L. McGuinness ◽  
J. Humphries ◽  
M. Waltham ◽  
K. G. Burnand ◽  
M. Collins ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Vessel Wall ◽  
Time Course ◽  
Thrombus Formation ◽  
Vena Cava ◽  
Steady Increase ◽  
Time Interval ◽  
Venous Thrombus ◽  
Scanning Electron

Summary Objective. Infusing monocytes that have been stimulated to produce fibrinolytic activators and factors that regulate cell proliferation, migration and maturation, might enhance venous thrombus resolution. The aim of this study was to determine the time course of infused monocyte recruitment into venous thrombus in an appropriate model of this disease. Design and Methods. Thrombus was induced in the inferior vena cava of male Wistar rats using reduced flow (80-90% stenosis). The vessel wall was examined at 1hr by scanning electron microscopy. Resolving thrombi with surrounding vena cava were obtained at 1, 7, 14 and 21 days after induction (n = 8). Sections, taken at 0.5 mm intervals (10-15 sections per thrombus), were stained using haematoxylin, Martius Scarlet Blue and antibodies against monocytes, platelets and fibrin. Sections from human venous thrombi (n = 4) were similarly stained. The area occupied by monocytes (in relative pixel units, RPU) was determined using computer aided image analysis. Peripheral rat blood monocytes were extracted, fluorescently labelled and injected intravenously into 7 rats prior to thrombus induction. Vena cava with thrombus was harvested 1 h, 2, 3, 4, 7, 14 and 25 days after induction and their fluorescence measured. The fluorescent content of the caval wall and thrombus was analysed in greater detail at 2 and 25 days after thrombus induction (n = 4 at each time interval). Results. Experimental thrombi were structurally similar to human thrombus and resolved within 14-21 days. Scanning electron microscopy showed minimal endothelial damage at 1 h with signs of early thrombus formation (platelet, red cell leukocyte and fibrin deposition). Neutrophils were the predominant leukocyte in the thrombus at 1 day, with monocytes making up only 0.3% (0.04% sem) of the area of the thrombus. There was a steady increase in thrombus monocyte content and by 21 days the percentage area of thrombus covered by monocytes had increased by over 35 fold to 11.5% (2.3% sem) (p <0.001). Initially, monocytes appeared around the edge of the thrombus and became more evenly distributed through the thrombus as resolution progressed. Labelled monocytes could be found in the circulation up to 1 week after infusion. The fluorescent content (RPU) of the thrombus increased over 25 days (mean RPU At 2 days 0.012, sem 0.005; mean RPU at 25 days 1.062, sem 0.252, p = 0.008). The number of labelled monocytes in the vessel wall peaked at 2 days and decreased thereafter.

Scanning electron microscope assessment of exocytotic changes in purified gonadotropes

1995 ◽  
Vol 144 (2) ◽  
pp. 193-200 ◽  
Author(s):  
J Mizuki ◽  
N Masumoto ◽  
M Tahara ◽  
K Fukami ◽  
A Mammoto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Endocrine Cells ◽  
Time Course ◽  
Gnrh Antagonist ◽  
Three Dimensional ◽  
Argon Laser ◽  
Pituitary Cells ◽  
Hole Structure ◽  
Scanning Electron

Abstract These studies were undertaken to characterize the exocytotic changes in purified gonadotropes by three-dimensional imaging using scanning electron microscopy. Rat gonadotropes were purified using a fluorescence-activated cell sorter and an argon laser treatment system. The purified gonadotropes were stimulated with GnRH under various conditions and fixed for scanning electron microscopy. After the GnRH stimulation, many 'hole' structures (diameter 0·1–0·5 μm) were observed on the cell surface, and notably the population of cells with 10 or more holes was clearly increased. The pattern of the time-course of the changes in this population was perfectly consistent with the LH secretory profile of pituitary cells, and their formation of the cells with 10 or more holes was completely inhibited by pretreatment with a GnRH antagonist. Our data suggest that the hole structure represents an exocytotic opening site and that regulated exocytosis in purified gonadotropes can be evaluated by scanning electron microscopy. This method may be widely applicable to other endocrine cells. Journal of Endocrinology (1995) 144, 193–200

Time Course of the Secondary Deposition of Incrusting Materials on Bordered Pit Membranes in Cryptomeria Japonica

IAWA Journal ◽  
1998 ◽  
Vol 19 (3) ◽  
pp. 285-299 ◽  
Author(s):  
Yuzou Sano ◽  
Ryogo Nakada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Ultraviolet Light ◽  
Cryptomeria Japonica ◽  
Time Course ◽  
Middle Layer ◽  
Bordered Pit ◽  
Innermost Layer ◽  
Scanning Electron

Bordered pit membranes of Cryptomeria japonica were examined successively from the outermost sapwood to the heartwood by scanning electron microscopy and by ultraviolet microspectrophotometry in an attempt to evaluate the time course of the secondary deposition of incrusting materials and to gain clues to their chemical composition. Scanning electron microscopy revealed that the bordered pit membranes were covered by incrusting materials from the middle layer of the sapwood to the heartwood. Both the amount and the appearance of the deposited incrusting materials differed among four regions of the wood, namely, the middle to inner layer of the sapwood, the innermost layer of the sapwood, the intermediate wood and the heartwood. From our results it appears that, in C. japonica, incrusting materials are deposited on bordered pit membranes by stages over several years. Apparent absorption of ultraviolet light by the bordered pit membranes was detected in the analysis of the innermost layer of the sapwood, the intermediate wood and the heartwood. The incrusting materials deposited in these zones were probably phenolic compounds. However, differences in the manner and extent of the absorption of ultraviolet light were found between these three regions of the wood. The results of microspectrophotometric analysis also suggested the phased deposition of incrusting materials at the bordered pit membranes of C. japonica.

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