scholarly journals Histological and ultrastructural nodule organization of the pea (Pisum sativum) mutant sgefix–-5 in the Sym33 gene encoding the transcription factor PsCYCLOPS/PsIPD3

2019 ◽  
Vol 17 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Anna V. Tsyganova ◽  
Kira A. Ivanova ◽  
Viktor E. Tsyganov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transcription Factor ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Gene Encoding ◽  
Defense Reactions ◽  
Transmission Electron ◽  
Infection Threads

Background. The transcription factor CYCLOPS/IPD3 is a key activator of the organogenesis of symbiotic nodules. Its participation in the development of infection threads and symbiosomes is also shown. In pea, three mutant alleles were identified for this gene (sym33-1 sym33-3). The phenotypic manifestations of the sym33-3 allele of the SGEFix-2 mutant, characterized by a leaky phenotype (the formation of two types of nodules: white and pinkish) were the most studied. The sym33-2 allele in the mutant SGEFix-5 was described as a strong allele, however, its phenotypic manifestations have not been studied in detail. Materials and methods. In this study, the histological and ultrastructural nodule organization of the SGEFix-5 mutant was analyzed using confocal laser scanning microscopy and transmission electron microscopy. Results. In the nodules locked infection threads were observed, from which no bacteria release into the cytoplasm of the plant cell occurs. In this case, in some infection threads, bacteria were degraded, which may indicate the activation of strong defense reactions in the nodules of the SGEFix-5 mutant. Conclusions. The sym33-2 allele in the mutant SGEFix-5 is a strong allele, which triggers the severe defense reactions, when rhizobia are already perceived as pathogens in infection threads.

Microtubule targeted therapeutics loaded polymeric assembled nanospheres for potentiation of antineoplastic activity

2016 ◽  
Vol 186 ◽  
pp. 45-59 ◽  
Author(s):  
Radhika Poojari ◽  
Rohit Srivastava ◽  
Dulal Panda
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Laser Scanning ◽  
Present Approach ◽  
Laser Scanning Microscopy ◽  
Microtubule Assembly ◽  
Confocal Laser ◽  
Cancer Cell Proliferation ◽  
Transmission Electron ◽  
Hepatocarcinoma Cells

Polymeric nanoassemblies represent an attractive strategy for efficient cellular internalization of microtubule targeted anticancer drugs. Using dynamic light scattering, zeta potential, transmission electron microscopy and scanning electron microscopy, the physical properties and surface morphology of microtubule-binding PEGylated PLGA assembled nanospheres (100–200 nm) were analyzed. The present approach leads to strong internalization as observed by confocal laser scanning microscopy and transmission electron microscopy in hepatocarcinoma cells. The effect of these nanoassemblies on microtubules and mitosis were explored using immunofluorescence microscopy. The effects of these nanoassemblies on cancer cell proliferation and cell death revealed their antitumor enhancing effects. Perturbation of the microtubule assembly, mitosis and nuclear modulations potentiated the antineoplastic effects delivered via nanospheres in hepatocarcinoma cells. The extensive biomolecular and physical characterizations of the synthesized nanoassemblies will help to design potent therapeutic materials and the present approach can be applied to deliver microtubule-targeted drugs for liver cancer therapy.

scholarly journals Ultrastructure and Functional Morphology of the Appendages in the Reef-Building Sedentary Polychaete Sabellaria Alveolata (Annelida, Sedentaria, Sabellida)

2020 ◽  
Author(s):  
Christian Meyer ◽  
Thomas André ◽  
Günter Purschke
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Blood Vessels ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Entire Body ◽  
Receptor Cells ◽  
Body Regions ◽  
Transmission Electron

Abstract Background: The sedentary polychaete Sabellaria alveolata, the sandcastle or honeycomb worm, possesses four different kinds of appendages besides the parapodia: opercular papillae, tentacular filaments, palps, and branchiae. It exhibits a highly specialized anterior end, the operculum, formed by the prostomium, peristomium, and two anterior segments. Besides the median organ, the operculum comprises opercular papillae, tentacular filaments, and palps. Paired branchiae are present from the second thoracic chaetiger onwards on the posteriorly following segments except for the last ones. Only the palps have been studied thus far by transmission electron microscopy in late larvae of a different species. In order to bridge the data gap, we investigated the appendages of S. alveolata by applying light microscopy, confocal laser scanning microscopy, scanning, and transmission electron microscopy. Results: In S. alveolata the entire body is covered by a thin cuticle characterized by the absence of layers of parallel collagen fibers with no differentiation between the various body regions including the branchiae. The opercular papillae bear numerous tufts of receptor cells and lack motile cilia. The tentacular filaments show a distinctive ciliation pattern; their most conspicuous morphological feature is their cell-free cartilaginous endoskeletal structure enclosed by ECM. Besides musculature the filaments include a single coelomic cavity but blood vessels are absent. The palps are ciliated with two coelomic cavities and a single blind-ending blood vessel. Besides external ciliation and receptor cells, the coelomate branchiae are highly vascularized and equipped with numerous blood spaces extending deep into the basal regions of the epidermal cells (diffusion distances: 150–400nm). Conclusions: All appendages, including the branchiae, bear receptor cells and, as such, are sensory. The opercular papillae resemble typical parapodial cirri. In contrast, the tentacular filaments have a double function: sensing, collecting and transporting particles. A similarity to branchiae can be excluded. The palps are typical grooved palps similar to another sabellariid studied. A revised classification of polychaete branchiae is suggested; thereby, the branchiae of S. alveolata belong to the most common type comprising coelom, musculature, and blood vessels. The results indicate that diffusion distances between blood and environment have been underestimated in many cases.

scholarly journals Legionella dumoffii DjlA, a Member of the DnaJ Family, Is Required for Intracellular Growth

2004 ◽  
Vol 72 (6) ◽  
pp. 3592-3603 ◽  
Author(s):  
Hiroko Ohnishi ◽  
Yoshimitsu Mizunoe ◽  
Akemi Takade ◽  
Yoshitaka Tanaka ◽  
Hiroshi Miyamoto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Parental Strain ◽  
Laser Scanning ◽  
Bartonella Henselae ◽  
Alveolar Epithelial Cells ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Intracellular Growth ◽  
Transmission Electron

ABSTRACT Legionella dumoffii is one of the common causes of Legionnaires' disease and is capable of replicating in macrophages. To understand the mechanism of survival within macrophages, transposon mutagenesis was employed to isolate the genes necessary for intracellular growth. We identified four defective mutants after screening 790 transposon insertion mutants. Two transposon insertions were in genes homologous to icmB or dotC, within dot/icm loci, required for intracellular multiplication of L. pneumophila. The third was in a gene whose product is homologous to the 17-kDa antigen forming part of the VirB/VirD4 type IV secretion system of Bartonella henselae. The fourth was in the djlA (for “dnaj-like A”) gene. DjlA is a member of the DnaJ/Hsp40 family. Transcomplementation of the djlA mutant restored the parental phenotype in J774 macrophages, A549 human alveolar epithelial cells, and the amoeba Acanthamoeba culbertsoni. Using confocal laser-scanning microscopy and transmission electron microscopy, we revealed that in contrast to the wild-type strain, L. dumoffii djlA mutant-containing phagosomes were unable to inhibit phagosome-lysosome fusion. Transmission electron microscopy also showed that in contrast to the virulent parental strain, the djlA mutant was not able to recruit host cell rough endoplasmic reticulum. Furthermore, the stationary-phase L. dumoffii djlA mutants were more susceptible to H2O2, high osmolarity, high temperature, and low pH than was their parental strain. These results indicate that DjlA is required for intracellular growth and organelle trafficking, as well as bacterial resistance to environmental stress. This is the first report demonstrating that a single DjlA-deficient mutant exhibits a distinct phenotype.

scholarly journals Scanning Transmission X-Ray, Laser Scanning, and Transmission Electron Microscopy Mapping of the Exopolymeric Matrix of Microbial Biofilms

2003 ◽  
Vol 69 (9) ◽  
pp. 5543-5554 ◽  
Author(s):  
J. R. Lawrence ◽  
G. D. W. Swerhone ◽  
G. G. Leppard ◽  
T. Araki ◽  
X. Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Laser Scanning ◽  
Heterotrophic Bacteria ◽  
Molecular Probes ◽  
Laser Scanning Microscopy ◽  
Biochemical Basis ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

ABSTRACT Confocal laser scanning microscopy (CLSM), transmission electron microscopy (TEM), and soft X-ray scanning transmission X-ray microscopy (STXM) were used to map the distribution of macromolecular subcomponents (e.g., polysaccharides, proteins, lipids, and nucleic acids) of biofilm cells and matrix. The biofilms were developed from river water supplemented with methanol, and although they comprised a complex microbial community, the biofilms were dominated by heterotrophic bacteria. TEM provided the highest-resolution structural imaging, CLSM provided detailed compositional information when used in conjunction with molecular probes, and STXM provided compositional mapping of macromolecule distributions without the addition of probes. By examining exactly the same region of a sample with combinations of these techniques (STXM with CLSM and STXM with TEM), we demonstrate that this combination of multimicroscopy analysis can be used to create a detailed correlative map of biofilm structure and composition. We are using these correlative techniques to improve our understanding of the biochemical basis for biofilm organization and to assist studies intended to investigate and optimize biofilms for environmental remediation applications.

scholarly journals Cyanobacterial calcification in modern microbialites at the submicrometer-scale

2013 ◽  
Vol 10 (2) ◽  
pp. 3311-3339 ◽  
Author(s):  
E. Couradeau ◽  
K. Benzerara ◽  
E. Gérard ◽  
I. Estève ◽  
D. Moreira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Morphology ◽  
Laser Scanning ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Advanced Stages

Abstract. The search for microfossils in the geological record has been a long-term challenge. Part of the problem comes from the difficulty of identifying such microfossils unambiguously, since they can be morphologically confused with abiotic biomorphs. One route to improve our ability to correctly identify microfossils consists in studying fossilization processes affecting bacteria in modern settings. We studied the initial stages of fossilization of cyanobacterial cells in modern microbialites from Lake Alchichica (Mexico), a Mg-rich hyperalkaline crater lake (pH 8.9) hosting currently growing stromatolites composed of aragonite [CaCO3] and hydromagnesite [Mg5(CO3)4(OH)2 × 4(H2O)]. Most of the biomass associated with the microbialites is composed of cyanobacteria. Scanning electron microscopy analyses coupled with confocal laser scanning microscopy observations were conducted to co-localize cyanobacterial cells and associated minerals. These observations showed that cyanobacterial cells affiliating to the order Pleurocapsales become specifically encrusted within aragonite with an apparent preservation of cell morphology. Encrustation gradients from non-encrusted to totally encrusted cells spanning distances of a few hundred micrometers were observed. Cells exhibiting increased levels of encrustation along this gradient were studied down to the nm-scale using a combination of focused ion beam (FIB) milling, transmission electron microscopy (TEM) and scanning transmission X-ray microscopy (STXM) at the C, O and N K-edges. Two different types of aragonite crystals were observed: one type was composed of needle-shaped nano-crystals growing outward from the cell body with a crystallographic orientation perpendicular to the cell wall, and another type was composed of larger crystals that progressively filled the cell interior. Organic matter (OM), initially co-localized with the cell, decreased in concentration and dispersed away from the cell while crystal growth occurred. As encrustation developed, OM progressively disappeared, but remaining OM showed the same spectroscopic signature. In the most advanced stages of fossilization, only the textural organization of the two types of aragonite recorded the initial cell morphology and spatial distribution.

Light Microscopy, Confocal Laser Scanning Microscopy And Scanning And Transmission Electron Microscopy Of Cerebellar Golgi Cells.

1999 ◽  
Vol 5 (S2) ◽  
pp. 1302-1303
Author(s):  
O. Castejόn ◽  
P Sims
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Synaptic Connections ◽  
Teleost Fishes ◽  
Golgi Cells ◽  
Transmission Electron ◽  
Molecular Layers

The cerebellar cortex of albino mice, hamsters, teleost fishes, primates and human have been examined by correlative microscopy to study the Golgi cell soma, dendritic processes, axonal plexus and synaptic connections in the granular and molecular layers. For light microscopy (LM) toluidinc blue stained-plastic embedded scmithin sections and Golgi light microscopy preparations were used. For confocal laser scanning microscopy (CLSM) of hamster cerebellum the FM4-64 fluorescent stain was used as intracellular tracer (1). Conventional and high resolution scanning electron microscopy (SEM) of teleost fishes, primates and human were coated with gold-palladium and chromium (2). I Transmission electron microscopy (TEM). either by ullrathin sections or frccze-clching replicas, were examined to characterize synaptic connections in the granular and molecular layers. The Golgi cells appeared in the granular layer as polygonal, stellate, round or fusiform microncurons. 10-25 μm in maximal dimension, surrounded by the granule cell groups. Golgi light microscopy.

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