Lessons from Worm Dendritic Patterning

2019 ◽  
Vol 42 (1) ◽  
pp. 365-383 ◽  
Author(s):  
Sharon Inberg ◽  
Anna Meledin ◽  
Veronika Kravtsov ◽  
Yael Iosilevskii ◽  
Meital Oren-Suissa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Light And Electron Microscopy ◽  
Dendritic Tree ◽  
Model System ◽  
Model Organisms ◽  
Structural Units ◽  
The Past ◽  
Structural And Functional Properties ◽  
Made In

The structural and functional properties of neurons have intrigued scientists since the pioneering work of Santiago Ramón y Cajal. Since then, emerging cutting-edge technologies, including light and electron microscopy, electrophysiology, biochemistry, optogenetics, and molecular biology, have dramatically increased our understanding of dendritic properties. This advancement was also facilitated by the establishment of different animal model organisms, from flies to mammals. Here we describe the emerging model system of a Caenorhabditis elegans polymodal neuron named PVD, whose dendritic tree follows a stereotypical structure characterized by repeating candelabra-like structural units. In the past decade, progress has been made in understanding PVD's functions, morphogenesis, regeneration, and aging, yet many questions still remain.

scholarly journals Soldering of 7075 Aluminum Alloy Using Ni-P and Cu-Cr Electrodeposited Interlayers

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4100
Author(s):  
Zbigniew Mirski ◽  
Ireneusz Ciepacz ◽  
Tomasz Wojdat
Keyword(s):  
Electron Microscopy ◽  
Shear Strength ◽  
Aluminum Alloy ◽  
Light And Electron Microscopy ◽  
7075 Aluminum Alloy ◽  
7075 Alloy ◽  
Aluminum Alloy 7075 ◽  
Soldered Joint ◽  
Measured Hardness ◽  
Made In

Direct soldering of the aluminum alloy 7075 is very difficult or even impossible. In order to make it possible, galvanic coatings and the procedures for their application on alloy surfaces were developed. The paper presents structures and mechanical properties of soldered joints of the 7075 alloy, made in indirect way with use of electrolytically deposited Ni-P and Cu-Cr coatings. Application of the newly developed Ni-P and Cu-Cr coatings on base surfaces of the 7075 alloy is described. The results of wettability examination of the S-Sn97Cu3 solder in the droplet test and by spreading on the coatings applied on the 7075 substrates are presented. The wettability angle of both coatings was lower than 30°. The results of metallographic examinations with use of light and electron microscopy are presented. It was shown that adhesion of metallic coatings to the aluminum alloy is good, exceeding shear strength of the S-Sn97Cu3 solder. Shear strength of soldered joint was equal to 35 ± 3 MPa. Measured hardness of the Ni-P interlayer reached high value of 471 HV 0.025.

A Light and Electron Microscopic Study in Serial Sections of Skeletal and Extraocular Muscles in Mouse Myotonic Dystrophy

1974 ◽  
Vol 32 ◽  
pp. 6-7
Author(s):  
Bruce R. Pachter ◽  
Jacob Davidowitz ◽  
Goodwin M. Breinin
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Myotonic Dystrophy ◽  
Skeletal Muscles ◽  
Light And Electron Microscopy ◽  
Hereditary Disease ◽  
Serial Sections ◽  
Electron Microscopic ◽  
Suitable Animal Model ◽  
Model Mouse

A suitable animal model (Mouse Strain Re-129 dy2j/dy2j) has been reported for myotonic dystrophy, a hereditary disease in which skeletal muscles degenerate. In the present study, another strain of mouse (Bar Harbor Strain C57BL/6J dy2j/dy2j), carrying this same myotonic gene (dy2j) was studied by light and electron microscopy (EM) in serial sections of epon embedded tissue.

Animal model: Light and electron microscopy of hepatocytes of cats with Chediak-Higashi syndrome

1985 ◽  
Vol 22 (4) ◽  
pp. 659-668 ◽  
Author(s):  
Ann M. Hargis ◽  
David J. Prieur ◽  
John M. Opitz ◽  
James F. Reynolds
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Light And Electron Microscopy ◽  
Chediak Higashi Syndrome

Helicobacter pylori-induced Gastritis in Experimentally Infected Conventional Piglets

2001 ◽  
Vol 38 (6) ◽  
pp. 667-678 ◽  
Author(s):  
T. Poutahidis ◽  
T. Tsangaris ◽  
G. Kanakoudis ◽  
I. Vlemmas ◽  
N. Iliadis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Helicobacter Pylori ◽  
Human Disease ◽  
Light And Electron Microscopy ◽  
Large Majority ◽  
Bacterial Cells ◽  
New Model ◽  
Pathologic Features ◽  
H Pylori

A conventional nonmutant animal that could be experimentally infected with Helicobacter pylori isolates would be a useful animal model for human H. pylori-associated gastritis. Gnotobiotic and barrier-born pigs are susceptible to H. pylori infection, but attempts to infect conventional pigs with this bacterium have been unsuccessful. In the present study, a litter of eight 20-day-old crossbreed piglets were purchased from a commercial farm. Six of them were orally challenged two to five times at different ages, between 29 and 49 days, with doses of H. pylori inoculum containing approximately 109 bacterial cells. Two animals served as controls. The inoculation program began 2 days postweaning when the piglets were 29 days of age. Prior to every inoculation, the piglets were fasted and pretreated with cimetidine, and prior to the first and second inoculation each piglet also was pretreated with dexamethasone. The challenged piglets were euthanasized between 36 and 76 days of age. H. pylori colonized all six inoculated piglets. The pathology of the experimentally induced gastritis was examined macroscopically and by light and electron microscopy. H. pylori induced a severe lymphocytic gastritis in the conventional piglets and reproduced the large majority of the pathologic features of the human disease. Therefore, the conventional piglet represents a promising new model for study of the various pathogenic mechanisms involved in the development of lesions of the human H. pyloriassociated gastritis.

Cryo-fixation and associated developments in transmission electron microscopy: a cool future for nematology

Nematology ◽  
2016 ◽  
Vol 18 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Wim Bert ◽  
Dieter Slos ◽  
Olivier Leroux ◽  
Myriam Claeys
Keyword(s):  
Electron Microscopy ◽  
Cell Biology ◽  
Electron Tomography ◽  
Light And Electron Microscopy ◽  
Three Dimensional ◽  
Freeze Substitution ◽  
Model Organisms ◽  
Fixation Method ◽  
Dimensional Reconstruction ◽  
Fixation Techniques

At present, the importance of sample preparation equipment for electron microscopy represents the driving force behind major breakthroughs in microscopy and cell biology. In this paper we present an introduction to the most commonly used cryo-fixation techniques, with special attention paid towards high-pressure freezing followed by freeze substitution. Techniques associated with cryo-fixation, such as immunolocalisation, cryo-sectioning, and correlative light and electron microscopy, are also highlighted. For studies that do not require high resolution, high quality results, or the immediate arrest of certain processes, conventional methods will provide answers to many questions. For some applications, such as immunocytochemistry, three-dimensional reconstruction of serial sections or electron tomography, improved preservation of the ultrastructure is required. This review of nematode cryo-fixation highlights that cryo-fixation not only results in a superior preservation of fine structural details, but also underlines the fact that some observations based on results solely obtained through conventional fixation approaches were either incorrect, or otherwise had severe limitations. Although the use of cryo-fixation has hitherto been largely restricted to model organisms, the advantages of cryo-fixation are sufficiently self-evident that we must conclude that the cryo-fixation method is highly likely to become the standard for nematode fixation in the near future.

Initiation of placentation in the pig

1984 ◽  
Vol 42 ◽  
pp. 730-731
Author(s):  
J.L. Keys
Keyword(s):  
Electron Microscopy ◽  
Developmental Stages ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Microscopic Structure ◽  
Initial Attachment ◽  
Tissue Samples ◽  
The Past ◽  
Early Developmental Stages ◽  
Early Developmental

The microscopic structure of the mature placenta in domesticated species has been described in many publications but the early developmental stages have only been studied in detail within the past decade. The earliest date previously cited for initial attachment of the porcine trophoblast to the maternal epithelium is 14 to 18 days of gestation. This investigation was undertaken to establish morphological changes in the maternal epithelium in preparation for this event.Four or 5 nulliparous gilts were slaughtered on each of d10 and d13 of the estrous cycle and pregnancy (d0=1st d of estrus), and tissue samples prepared for correlative light and electron microscopy. Samples were compared between gilts on equivalent days of the cycle/pregnancy in order to determine endometrial changes specific to pregnancy. Sites adjacent to embryos were contrasted with those lacking trophoblastic contact within the same animal to investigate whether epithelial adaptations for attachment are localized to trophoblast proximity or represent a generalized uterine response.

scholarly journals Conditional surrender in one generation: determining the reproductive roles of mouse embryo lethal genes by embryo complementation

2020 ◽  
Author(s):  
John C Schimenti
Keyword(s):  
Animal Model ◽  
Molecular Mechanisms ◽  
Laboratory Mouse ◽  
Embryonic Stem ◽  
Model System ◽  
Mammalian Development ◽  
Long Period ◽  
The Past ◽  
Scientific Infrastructure ◽  
Lethal Genes

Abstract The laboratory mouse is the most widely used animal model for studying the genetics and biology of mammalian development and reproduction. Embryonic stem cell (ESC) gene targeting technology, and the sophisticated genomic manipulations it allowed, was unique to this organism for a long period of time; this was a major factor in the mouse’s rise to pre-eminence as a model system over the past three decades or so. The recent advent of CRISPR/Cas9 technology has democratized the application of genome editing to essentially all organisms. Nevertheless, the scientific infrastructure behind the mouse still makes it the organism of choice for studying molecular mechanisms of mammalian development, and for modeling human development and disease.

scholarly journals Brown Algal Model Organisms

2020 ◽  
Vol 54 (1) ◽  
pp. 71-92
Author(s):  
Susana M. Coelho ◽  
J. Mark Cock
Keyword(s):  
Novel Species ◽  
Classical Model ◽  
Saccharina Japonica ◽  
Model System ◽  
Model Organisms ◽  
Phylogenetic Groups ◽  
The Past ◽  
Genomic Tools ◽  
Modern Genomic ◽  
Multicellular Organisms

Model organisms are extensively used in research as accessible and convenient systems for studying a particular area or question in biology. Traditionally, only a limited number of organisms have been studied in detail, but modern genomic tools are enabling researchers to extend beyond the set of classical model organisms to include novel species from less-studied phylogenetic groups. This review focuses on model species for an important group of multicellular organisms, the brown algae. The development of genetic and genomic tools for the filamentous brown alga Ectocarpus has led to it emerging as a general model system for this group, but additional models, such as Fucus or Dictyota dichotoma, remain of interest for specific biological questions. In addition, Saccharina japonica has emerged as a model system to directly address applied questions related to algal aquaculture. We discuss the past, present, and future of brown algal model organisms in relation to the opportunities and challenges in brown algal research.

Phase and Electron Microscopy of Olfactory Bulb After Sectioning of its Peduncle

1970 ◽  
Vol 28 ◽  
pp. 116-117
Author(s):  
Juan F. Estable-Puig ◽  
Rosita F. de Estable-Puig
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Albino Rats ◽  
Microscopy Observation ◽  
Olfactory Bulbs ◽  
Post Operation ◽  
Terminal Degeneration ◽  
Made In

The unilateral section of the olfactory peduncle was made in adult albino rats in order to produce axonal and terminal degeneration of the whole system of centrifugal projections. This experiment was carried out with a double purpose. First, to tipify the different structural modes of axonal and terminal degeneration in a correlative light and electron microscopy study. Second, to study the distribution of these central projections to the bulb. The animals were sacrificed by fixation-perfusion 4 to 7 days post-operation and samples of olfactory bulbs were processed as routinely for electron microscopy observation. Thick sections stained with paraphenylenediamine (PPDA)(1) were utilized for phase observation.

Endogenous Enzyme-responsive Nanoplatforms for Anti-tumor Therapy

2021 ◽  
Vol 22 ◽  
Author(s):  
Xue-Fang Lou ◽  
Yong-Zhong Du ◽  
Xiao-Ling Xu
Keyword(s):  
Drug Delivery ◽  
Animal Model ◽  
Drug Delivery Systems ◽  
Active Drug ◽  
Tumor Therapy ◽  
Delivery Systems ◽  
The Past ◽  
Great Progress ◽  
Extended Circulation ◽  
Made In

: The emergency of responsive drug delivery systems has contributed to the reduced cytotoxicity, the improved permeability in tissues and extended circulation time of the active drug. Of particular, enzyme-responsive nanoplatforms have attracted a lot due to the specificity and efficiency of an enzyme-catalyzed reaction. In this review, enzyme-based mono responsive drug delivery systems designed in the past 5 years were summarized. These drug delivery systems were introduced by different tumor-related enzymes such as matrix metalloproteinase, esterase, hyaluronidase, caspase and cathepsin. Moreover, the enzyme-sensitive nanoplatforms activated by dual-stimuli were also described. Although great progress had been made in the past years, the translation into clinical practice was still difficult. Thus, three obstacles (enzyme heterogeneity, reaction environment, animal model) were also discussed. In short, enzymeactivated drug delivery systems offer great potential in treating cancers.

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