scholarly journals The Barley Apoptosis Suppressor Homologue Bax Inhibitor-1 Compromises Nonhost Penetration Resistance of Barley to the Inappropriate Pathogen Blumeria graminis f. sp. tritici

2004 ◽  
Vol 17 (5) ◽  
pp. 484-490 ◽  
Author(s):  
Ruth Eichmann ◽  
Holger Schultheiss ◽  
Karl-Heinz Kogel ◽  
Ralph Hückelhoven
Keyword(s):  
Cell Death ◽  
Laser Scanning ◽  
Penetration Resistance ◽  
Suppressor Gene ◽  
Blumeria Graminis ◽  
Epidermal Cells ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Over Expression ◽  
Enhanced Expression

BAX inhibitor-1 (BI-1) proteins have been characterized as suppressors of programmed cell death in mammals and plants. The barley BI-1 is a suppressor of nonspecific background resistance and mlo-mediated penetration resistance to the biotrophic fungal pathogen Blumeria graminis f. sp. hordei when overexpressed in epidermal cells of barley. We report here that BI-1 expression is also slightly up-regulated during interaction with the inappropriate wheat pathogen Blumeria graminis f. sp. tritici. Significantly, over-expression of BI-1 in single epidermal cells of barley by microprojectile-mediated transformation rendered cells susceptible to penetration by inappropriate B. graminis f. sp. tritici. The degree of transgene-induced accessibility to B. graminis f. sp. tritici was thereby similar to the effect achieved by overexpression of the defense suppressor gene Mlo and could not be further enhanced by double expression of both BI-1 and Mlo. Confocal laser scanning microscopy was used to locate a functional green fluorescing GFP:BI-1 fusion protein in endomembranes and the nuclear envelope of barley epidermal cells. Together, enhanced expression of barley BI-1 suppresses penetration resistance to B. graminis f. sp. tritici, linking barley nonhost resistance with cell death regulation.

scholarly journals High Adhesion and Increased Cell Death Contribute to Strong Biofilm Formation in Klebsiella pneumoniae

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 277
Author(s):  
Siddhi Desai ◽  
Kinjal Sanghrajka ◽  
Devarshi Gajjar
Keyword(s):  
Cell Death ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Extracellular Dna ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
High Adhesion ◽  
Biofilm Matrix

Klebsiella pneumoniae (Kp), is a frequent cause of hospital and community-acquired infections and WHO had declared it as a “priority pathogen”. Biofilm is a major virulence factor of Kp and yet the mechanism of strong biofilm formation in Kp is unclear. A key objective of the present study is to investigate the differences between strong and weak biofilms formed by clinical isolates of Kp on various catheters and in different media conditions and to identify constituents contributing to strong biofilm formation. Quantification of matrix components (extracellular DNA (eDNA), protein, exopolysaccharides (EPS), and bacterial cells), confocal laser scanning microscopy (CLSM), field emission gun scanning electron microscopy (FEG-SEM) and flow-cytometry analysis were performed to compare strong and weak biofilm matrix. Our results suggest increased biofilm formation on latex catheters compared to silicone and silicone-coated latex catheters. Higher amounts of eDNA, protein, EPS, and dead cells were observed in the strong biofilm of Kp. High adhesion capacity and cell death seem to play a major role in formation of strong Kp biofilms. The enhanced eDNA, EPS, and protein in the biofilm matrix appear as a consequence of increased cell death.

scholarly journals Microscopic Photosensitization: A New Tool to Investigate the Role of Mitochondria in Cell Death

2002 ◽  
Vol 2 ◽  
pp. 1198-1208 ◽  
Author(s):  
May-Ghee Lum ◽  
Tetsuhiro Minamikawa ◽  
Phillip Nagley
Keyword(s):  
Cell Death ◽  
Laser Irradiation ◽  
Laser Scanning ◽  
Annexin V ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Rapid Loss ◽  
Active Involvement ◽  
Induction Of Apoptosis

Active involvement of mitochondria in cell death has been well-documented, but local apoptotic signaling between subsets of mitochondria has been poorly explored to date. Using mitochondrially localized CMXRos as a photosensitizer coupled to laser irradiation by confocal laser scanning microscopy, we demonstrate that partial irradiation of about half the mitochondria in human 143B TK–cells induces rapid loss of mitochondrial membrane potential (ΔΨm) in nonirradiated mitochondria. Cells so partially irradiated show apoptotic indications, including mobilization of cytochrome c and binding of annexin V within 2 h following irradiation. The loss of ΔΨm in nonirradiated mitochondria did not occur in cells photoirradiated in the absence of CMXRos. Increasing the proportion of irradiated mitochondria in each cell (up to about 50%) generated a correspondingly greater percentage of cells in which nonirradiated mitochondria lost ΔΨm and which also showed apoptotic indications. Only at the highest level of irradiation (global for all mitochondria in one cell) were signs of necrosis evident (judged by uptake of propidium iodide). Because laser irradiation is specific to the subpopulation of mitochondria targeted, the data imply that a signal emanating from irradiated mitochondria is processed by their nonirradiated counterparts. We conclude that intermitochondrial signaling occurs in the subcellular response to induction of apoptosis.

scholarly journals Structural Evidence of Programmed Cell Death Induction by Tungsten in Root Tip Cells of Pisum sativum

Plants ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 62 ◽  
Author(s):  
Ioannis-Dimosthenis Adamakis ◽  
Eleftherios Eleftheriou
Keyword(s):  
Cell Death ◽  
Pisum Sativum ◽  
Programmed Cell Death ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Root Tip ◽  
Confocal Laser ◽  
Golgi Bodies ◽  
Tip Cells ◽  
Root Tip Cells

Previous studies have shown that excess tungsten (W), a rare heavy metal, is toxic to plant cells and may induce a kind of programmed cell death (PCD). In the present study we used transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM) to investigate the subcellular malformations caused by W, supplied as 200 mg/L sodium tungstate (Na2WO4) for 12 or 24 h, in root tip cells of Pisum sativum (pea), The objective was to provide additional evidence in support of the notion of PCD induction and the presumed involvement of reactive oxygen species (ROS). It is shown ultrastructurally that W inhibited seedling growth, deranged root tip morphology, induced the collapse and deformation of vacuoles, degraded Golgi bodies, increased the incidence of multivesicular and multilamellar bodies, and caused the detachment of the plasma membrane from the cell walls. Plastids and mitochondria were also affected. By TEM, the endoplasmic reticulum appeared in aggregations of straight, curved or concentric cisternae, frequently enclosing cytoplasmic organelles, while by CLSM it appeared in bright ring-like aggregations and was severely disrupted in mitotic cells. However, no evidence of ROS increase was obtained. Overall, these findings support the view of a W-induced vacuolar destructive PCD without ROS enhancement.

scholarly journals Specific Intracellular Uptake of Herceptin-Conjugated CdSe/ZnS Quantum Dots into Breast Cancer Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Seung-Jin Han ◽  
Pierson Rathinaraj ◽  
Soo-Young Park ◽  
Young Kyoo Kim ◽  
Joon Hyung Lee ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Quantum Dots ◽  
Cell Death ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Laser Scanning ◽  
Specific Binding ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Core Shell

Herceptin, a typical monoclonal antibody, was immobilized on the surface of CdSe/ZnS core-shell quantum dots (QDs) to enhance their specific interactions with breast cancer cells (SK-BR3). The mean size of the core-shell quantum dots (28 nm), as determined by dynamic light scattering, increased to 86 nm after herceptin immobilization. Thein vitrocell culture experiment showed that the keratin forming cancer cells (KB) proliferated well in the presence of herceptin-conjugated QDs (QD-Her, 5 nmol/mL), whereas most of the breast cancer cells (SK-BR3) had died. To clarify the mechanism of cell death, the interaction of SK-BR3 cells with QD-Her was examined by confocal laser scanning microscopy. As a result, the QD-Her bound specifically to the membrane of SK-BR3, which became almost saturated after 6 hours incubation. This suggests that the growth signal of breast cancer cells is inhibited completely by the specific binding of herceptin to the Her-2 receptor of SK-BR3 membrane, resulting in cell death.

scholarly journals Activation of the Cell Wall Stress Response in Pseudomonas aeruginosa Infected by a Pf4 Phage Variant

2020 ◽  
Vol 8 (11) ◽  
pp. 1700
Author(s):  
Damien Tortuel ◽  
Ali Tahrioui ◽  
Sophie Rodrigues ◽  
Mélyssa Cambronel ◽  
Amine M. Boukerb ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stress Response ◽  
Laser Scanning ◽  
Cell Envelope ◽  
Wall Stress ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Guanosine Monophosphate ◽  
Confocal Laser ◽  
Enhanced Expression

Pseudomonas aeruginosa PAO1 has an integrated Pf4 prophage in its genome, encoding a relatively well-characterized filamentous phage, which contributes to the bacterial biofilm organization and maturation. Pf4 variants are considered as superinfectives when they can re-infect and kill the prophage-carrying host. Herein, the response of P. aeruginosa H103 to Pf4 variant infection was investigated. This phage variant caused partial lysis of the bacterial population and modulated H103 physiology. We show by confocal laser scanning microscopy that a Pf4 variant-infection altered P. aeruginosa H103 biofilm architecture either in static or dynamic conditions. Interestingly, in the latter condition, numerous cells displayed a filamentous morphology, suggesting a link between this phenotype and flow-related forces. In addition, Pf4 variant-infection resulted in cell envelope stress response, mostly mediated by the AlgU and SigX extracytoplasmic function sigma factors (ECFσ). AlgU and SigX involvement may account, at least partly, for the enhanced expression level of genes involved in the biosynthesis pathways of two matrix exopolysaccharides (Pel and alginates) and bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) metabolism.

Re-establishment of the interphase microtubule array in vacuolated plant cells, studied by confocal microscopy and 3-D imaging

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 897-904
Author(s):  
D.J. Flanders ◽  
D.J. Rawlins ◽  
P.J. Shaw ◽  
C.W. Lloyd
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Cell Plate ◽  
Datura Stramonium ◽  
Epidermal Cells ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Computer Methods ◽  
Cortical Array ◽  
Transvacuolar Strands

There are two conflicting ideas about the site of reassembly of cortical microtubules following cytokinesis. Some observations indicate that microtubules (MTs) radiate from the surface of the postcytokinetic nuclear envelope, before becoming organized at the cortex. On the other hand, results of regrowth experiments, following MT depolymerization by drugs, suggest that the array may assemble directly upon the cortex. In this study, we have taken advantage of the significant separation between nucleus and cortex, in large, vacuolated epidermal cells, to determine which of these two potential sites supports the earliest stages of regrowth in the undrugged, native state. MTs in stem epidermis of Datura stramonium L. were stained by indirect immunofluorescence. This was performed on hand-cut sections of tissue in which the cells were not separated by enzymes or distorted by air- drying. Epidermal cells with these sheets were optically sectioned by confocal laser scanning microscopy and three-dimensional images reconstructed, rotated and viewed stereoscopically using computer methods. During metaphase, no MTs can be detected at the cortex but MTs begin to re-colonize the cell surface during early cytokinesis. Thick cables of MTs radiate from the nucleus parallel to the cell plate as well as in other directions, along transvacuolar strands, out to the cortex. Microtubules grow out over the cortex where the thick bundles make contact, as well as from the edges of the fully developed phragmoplast. These early cortical MTs do not form regular transverse arrays: they either appear to be random or to grow in branching V- shaped patterns. The cortical array is therefore not organized immediately but at a later stage. It is concluded that MT bundles, radiating from the nucleus, are involved in the earliest stages of cortical array formation.

scholarly journals New Insights into the Life Cycle of the Wheat Powdery Mildew: Direct Observation of Ascosporic Infection in Blumeria graminis f. sp. tritici

2015 ◽  
Vol 105 (6) ◽  
pp. 797-804 ◽  
Author(s):  
Tünde Jankovics ◽  
Judit Komáromi ◽  
Attila Fábián ◽  
Katalin Jäger ◽  
Gyula Vida ◽  
...  
Keyword(s):  
Life Cycle ◽  
Direct Observation ◽  
Laser Scanning ◽  
Genetic Recombination ◽  
Blumeria Graminis ◽  
Laser Scanning Microscopy ◽  
Recent Analysis ◽  
Confocal Laser ◽  
Powdery Mildews

Although Blumeria graminis is an intensively studied pathogen, an important part of its life cycle (namely, the way ascospores initiate primary infections on cereal leaves) has not yet been explored in detail. This study reports, for the first time, the direct observation of this process in B. graminis f. sp. tritici using light and confocal laser-scanning microscopy. All the germinated ascospores produced a single germ tube type both in vitro and on host plant surfaces; therefore, the ascosporic and conidial germination patterns are markedly different in this fungus, in contrast to other powdery mildews. Germinated ascospores penetrated the epidermal cells of wheat leaves and produced haustoria as known in the case of conidial infections. This work confirmed earlier studies reporting that B. graminis chasmothecia collected from the field do not contain mature ascospores, only asci filled with protoplasm; ascospore development is induced by moist conditions and is a fast process compared with other powdery mildews. Although ascosporic infections are frequent in B. graminis f. sp. tritici in the field, as shown by this study and other works as well, a recent analysis of the genomes of four isolates revealed the signs of clonal or near-clonal reproduction. Therefore, chasmothecia and ascospores are probably more important as oversummering structures than genetic recombination factors in the life cycle of this pathogen.

scholarly journals A genetic tool for production of GFP-expressing Rhodopseudomonas palustris for visualization of bacterial colonization

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhongying Zhai ◽  
Jiao Du ◽  
Lijie Chen ◽  
Muhammad Rizwan Hamid ◽  
Xiaohua Du ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Growth Promotion ◽  
Bacterial Colonization ◽  
Rhodopseudomonas Palustris ◽  
Transformation Method ◽  
Epidermal Cells ◽  
Laser Scanning Microscopy ◽  
Systemic Resistance ◽  
Confocal Laser ◽  
Genetic Tool

Abstract Development of a genetic tool for visualization of photosynthetic bacteria (PSB) is essential for understanding microbial function during their interaction with plant and microflora. In this study, Rhodopseudomonas palustris GJ-22-gfp harboring the vector pBBR1-pckAPT-gfp was constructed using an electroporation transformation method and was used for dynamic tracing of bacteria in plants. The results showed that strain GJ-22-gfp was stable and did not affect the biocontrol function, and the Confocal Laser Scanning Microscopy (CLSM) results indicated it could successfully colonised on the surface of leaf and root of tobacco and rice. In tobacco leaves, cells formed aggregates on the mesophyll epidermal cells. While in rice, no aggregate was found. Instead, the fluorescent cells colonise the longitudinal intercellular spaces between epidermal cells. In addition, the results of strain GJ-22 on the growth promotion and disease resistance of tobacco and rice indicated that the different colonization patterns might be related to the bacteria could induce systemic resistance in tobacco.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

Sign in / Sign up

Export Citation Format

Share Document