A Method for Studying the Cellular Location of Lead in Lichens

1994 ◽  
Vol 26 (1) ◽  
pp. 83-90 ◽  
Author(s):  
C. Branquinho ◽  
D. H. Brown
Keyword(s):  
Chelating Agents ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Metal Cations ◽  
Disodium Edta ◽  
Cellular Location ◽  
Ammonium Pyrrolidinedithiocarbamate

AbstractA number of possible displacing agents have been tested for their ability to release extracellular bound lead from Cladonia portentosa. Metal cations (Ni and Cu), thiol–rich reagents (glutathione, ammonium pyrrolidinedithiocarbamate) and some chelating agents (EGTA, EDTA at pH 9·5 or pH 2·7) were ineffective or caused membrane damage. Disodium EDTA at pH 4·5 was found to be an effective displacing agent, although the Na caused some release of intracellular K without membrane damage. This displacement procedure showed that no Pb suppliedin the laboratory entered the protoplast in 2 h. The effect of Ca, Cu, Pb, and Sr on membrane integrity was investigated.

Effects of salinity stress on cellular location of elements and photosynthesis in Ramalina canariensis Steiner

2011 ◽  
Vol 43 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Paula MATOS ◽  
João CARDOSO-VILHENA ◽  
Rui FIGUEIRA ◽  
A. Jorge SOUSA
Keyword(s):  
Sea Water ◽  
Water Solution ◽  
Membrane Damage ◽  
Photochemical Efficiency ◽  
Membrane Integrity ◽  
Photosynthetic Apparatus ◽  
Saline Stress ◽  
Ion Distribution ◽  
Cellular Location ◽  
The Impact

AbstractThe impact of incubation in saline solutions of different concentrations on the uptake and cellular location of essential elements (Na+, K+, Mg2+ and Ca2+), and its effects on membrane integrity and on the photosynthetic apparatus, were investigated in the lichen Ramalina canariensis Steiner. Saline incubation resulted in a rapid uptake of Na+ and Mg2+ in the cell wall fraction, whereas in the intracellular fraction the accumulation of Na+ was slower. No changes were observed for intracellular Mg2+, suggesting that no generalized membrane damage occurred. Concomitantly with the increase in intracellular Na+, there was a specific loss of K+ from the cell interior, indicating that membrane permeability may have been compromised. Incubation in a 100% artificial sea water solution reduced the maximum photochemical efficiency of Photosystem II (Fv/Fm) by 17% after 5 min, and this inhibition increased with incubation time. In samples incubated in 100% artificial sea water solution for 2 h followed by 2 h incubation in deionized water, ion distribution and Fv/Fm did not recover to control values. The present findings show the importance of determining the cellular location of elements when assessing their physiological impact. Results indicate that saline stress may irreversibly impair photosynthesis, thus compromising lichen vitality.

IMPACT OF SORBITOL- INDUCED OSMOTIC STRESS ON SOME BIOCHEMICAL TRAITS OF POTATO IN VITRO

2020 ◽  
Vol 51 (4) ◽  
pp. 1038-1047
Author(s):  
Mawia & et al.
Keyword(s):  
Ascorbic Acid ◽  
Osmotic Stress ◽  
Cytoplasmic Membrane ◽  
Genotypic Variation ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Culture Collection ◽  
Nutritive Medium ◽  
Starting Point

This study had as principal objective identification of osmotic-tolerant potato genotypes by using "in vitro" tissue culture and sorbitol as a stimulating agent, to induce water stress, which was added to the  culture nutritive medium in different concentration (0,50, 110, 220, 330 and 440 mM).  The starting point was represented by plantlets culture collection, belonging to eleven potato genotypes: Barcelona, Nectar, Alison, Jelly, Malice, Nazca, Toronto, Farida, Fabulla, Colomba and Spunta. Plantlets were multiplied between two internodes to obtain microcuttings (in sterile condition), which were inoculated on medium. Sorbitol-induced osmotic stress caused a significant reduction in the ascorbic acid, while the concentration of proline, H2O2 and solutes leakage increased compared with the control. Increased the proline content prevented lipid peroxidation, which played a pivotal role in the maintenance of membrane integrity under osmotic stress conditions. The extent of the cytoplasmic membrane damage depends on osmotic stress severity and the genotypic variation in the maintenance of membranes stability was highly associated with the ability of producing more amounts of osmoprotectants (proline) and the non-enzymic antioxidant ascorbic acid in response to osmotic stress level. The results showed that the genotypes Jelly, Nectar, Allison, Toronto, and Colomba are classified as highly osmotic stress tolerant genotypes, while the genotypes Nazca and Farida are classified as osmotic stress susceptible ones.

scholarly journals Plasma membrane integrity: implications for health and disease

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Dustin A. Ammendolia ◽  
William M. Bement ◽  
John H. Brumell
Keyword(s):  
Plasma Membrane ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Whole Body ◽  
Plasma Membrane Integrity ◽  
Plasma Membrane Damage ◽  
Cellular Environment ◽  
Health And Disease ◽  
Repair Pathways ◽  
The Impact

AbstractPlasma membrane integrity is essential for cellular homeostasis. In vivo, cells experience plasma membrane damage from a multitude of stressors in the extra- and intra-cellular environment. To avoid lethal consequences, cells are equipped with repair pathways to restore membrane integrity. Here, we assess plasma membrane damage and repair from a whole-body perspective. We highlight the role of tissue-specific stressors in health and disease and examine membrane repair pathways across diverse cell types. Furthermore, we outline the impact of genetic and environmental factors on plasma membrane integrity and how these contribute to disease pathogenesis in different tissues.

scholarly journals Fluorescent Chitosan Nanogels Developed for Targeting Endothelial Cells of Axillary Lymph Nodes

2020 ◽  
Vol 4 (1) ◽  
pp. 12
Author(s):  
Miruna-Silvia Stan ◽  
Ionela Cristina Nica ◽  
Juliette Moreau ◽  
Maïté Callewaert ◽  
Cyril Cadiou ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Membrane Integrity ◽  
Simian Virus 40 ◽  
Cancer Diagnostics ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Microvascular Endothelial Cell ◽  
Axillary Lymph Nodes ◽  
Cell Periphery ◽  
Axillary Lymph

Nanogels are a novel class of three-dimensional cross-linked polymers able to retain high amounts of water in their network structure, with large potential applications in nanomedicine. In our study, the polymer matrix selected was chitosan, as this polysaccharide biopolymer composed of N-acetylglucosamine and glucosamine residues exhibits great biocompatibility and low toxicity. The preparation was performed by ionic gelation in the presence of hyaluronic acid and sodium tripolyphosphate, with rhodamine or fluorescein isothiocyanate molecules grafted on a chitosan backbone. In order to validate the possible usage of these chitosan-fluorophores conjugates for fluorescence imaging purposes in cancer diagnostics and therapy, their biological effect was assessed on SVEC4-10 cells (a simian virus 40-transformed mouse microvascular endothelial cell line). Cell viability, membrane integrity and nanogels uptake were examined following exposure for 6 and 24 h at concentrations up to 120 µg/mL. A good biocompatibility was obtained after both time intervals of incubation with nanogels, with no increase in cell death or membrane damage being noticed as compared to control. By examination on confocal laser scanning microscopy, both types of fluorescent nanogels agglomerated on the surface of the cell membrane, their cellular internalization being observed only for few cells, preferentially at the cell periphery. In conclusion, based on the biocompatibility of the nanogels, these can further incorporate gadolinium for an improved magnetic resonance imaging effect in nanomedicine.

Hydraulic consequences of enzymatic breakdown of grapevine pit membranes

2021 ◽  
Author(s):  
Ana Clara Fanton ◽  
Craig Brodersen
Keyword(s):  
Hydraulic Conductivity ◽  
Vascular System ◽  
Membrane Surface ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Biological Response ◽  
Plant Host ◽  
Important Species ◽  
Membrane Area ◽  
Pit Membrane

Abstract Xylella fastidiosa (Xf) is the xylem-dwelling bacterial agent associated with Pierce’s Disease (PD), which leads to significant declines in productivity in agriculturally important species like grapevine (Vitis vinifera). Xf spreads through the xylem network by digesting the pit membranes between adjacent vessels, thereby potentially changing the hydraulic properties of the stem. However, the effects of Xf on water transport varies depending on the plant host and the infection stage, presenting diverse outcomes. Here, we investigated the effects of polygalacturonase, an enzyme known to be secreted by Xf when it produces biofilm on the pit membrane surface, on stem hydraulic conductivity and pit membrane integrity. Experiments were performed on six grapevine genotypes with varying levels of PD resistance, with the expectation that pit membrane resistance to degradation by polygalacturonase may play a role in PD-resistance. Our objective was to study a single component of this pathosystem in isolation to better understand the mechanisms behind reported changes in hydraulics, thereby excluding the biological response of the plant to the presence of Xf in the vascular system. Pit membrane damage only occurred in stems perfused with polygalacturonase. Although the damaged pit membrane area was small (2-9% of the total pit aperture area), membrane digestion led to significant changes in the median air-seeding thresholds, and most importantly, shifted frequency distribution. Finally, enzyme perfusion also resulted in a universal reduction in stem hydraulic conductivity, suggesting the development of tyloses may not be the only contributing factor to reduced hydraulic conductivity in infected grapevine.

scholarly journals Effects of freezing and activation on membrane quality and DNA damage in Xenopus tropicalis and Xenopus laevis spermatozoa

2017 ◽  
Vol 29 (8) ◽  
pp. 1556 ◽  
Author(s):  
S. Morrow ◽  
J. Gosálvez ◽  
C. López-Fernández ◽  
F. Arroyo ◽  
W. V. Holt ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Subsequent Development ◽  
Xenopus Tropicalis ◽  
Model Organisms ◽  
Sperm Chromatin ◽  
Dna Integrity ◽  
Sperm Cryopreservation ◽  
Sperm Plasma Membrane

There is growing concern over the effect of sperm cryopreservation on DNA integrity and the subsequent development of offspring generated from this cryopreserved material. In the present study, membrane integrity and DNA stability of Xenopus laevis and Xenopus tropicalis spermatozoa were evaluated in response to cryopreservation with or without activation, a process that happens upon exposure to water to spermatozoa of some aquatic species. A dye exclusion assay revealed that sperm plasma membrane integrity in both species decreased after freezing, more so for X. laevis than X. tropicalis spermatozoa. The sperm chromatin dispersion (SCD) test showed that for both X. tropicalis and X. laevis, activated frozen spermatozoa produced the highest levels of DNA fragmentation compared with all fresh samples and frozen non-activated samples (P < 0.05). Understanding the nature of DNA and membrane damage that occurs in cryopreserved spermatozoa from Xenopus species represents the first step in exploiting these powerful model organisms to understand the developmental consequences of fertilising with cryopreservation-damaged spermatozoa.

scholarly journals New techniques for real-time monitoring of reverse osmosis membrane integrity for virus removal

2018 ◽  
Vol 13 (4) ◽  
pp. 947-957 ◽  
Author(s):  
V. S. Frenkel ◽  
Y. Cohen
Keyword(s):  
Real Time ◽  
Reverse Osmosis ◽  
Health Hazard ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Enteric Viruses ◽  
Water Stream ◽  
Potential Health ◽  
Integrity Monitoring ◽  
Virus Removal

Abstract This paper presents methodology, concept and results of the WateReuse Foundation project WFR – 09 – 06b when developing a high pressure membrane, reverse osmosis (RO) and nanofiltration (NF) online membrane integrity testing (MIT) technique. The use of pressure-driven membrane processes, particularly RO, has grown significantly over the past few decades in water treatment and reuse applications to safeguard water supplies against harmful pathogens and impurities. In principle, RO membranes should provide a complete physical barrier to the passage of nanosize pathogens (e.g., enteric viruses). However, in the presence of imperfections and/or membrane damage, membrane breaches as small as 20 to 30 nm can allow enteric viruses to pass through the membrane and contaminate the product water stream, thereby posing a potential health hazard that is of particular concern for potable water production. This project was focused on evaluating a pulsed-marker membrane integrity monitoring (PM-MIMo) approach for RO processes on the basis of the use of a fluorescent marker. The monitoring approach employs pulsed dosing (via a precision metering pump) of a marker into the RO feed stream coupled with online marker concentration monitoring in the RO permeate by an inline spectrofluorometer. Membrane integrity is then inferred on the basis of real-time analysis of the marker permeate time − profile concentration in response. The basic concept of the PM-MIMo approach for detecting membrane breaches was successfully demonstrated, by comparing intact and damaged membranes, in a series of experiments using a diagnostic plate-and-frame RO system and spiral-wound RO pilot system. Results of the developed technique are presented in the project report to allow the industry to consider adopting this technique for RO/NF online integrity monitoring.

scholarly journals Application of a viability-staining method for Mycobacterium leprae derived from the athymic (nu/nu) mouse foot pad

2005 ◽  
Vol 54 (3) ◽  
pp. 235-242 ◽  
Author(s):  
Ramanuj Lahiri ◽  
Baljit Randhawa ◽  
James Krahenbuhl
Keyword(s):  
Metabolic Activity ◽  
Staining Method ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Mycobacterium Leprae ◽  
Athymic Mouse ◽  
Experimental Conditions ◽  
Activity Data ◽  
Viability Staining ◽  
Foot Pad

Mycobacterium leprae cannot be cultured, so ascertaining viability of the organism remains a major obstacle, impeding many avenues of investigation. This study tested a two-colour, Syto9 and propidium iodide, fluorescence assay, which scores for membrane damage in individual bacilli, to determine if a rapid direct-count viability-staining technique can be reliably applied to M. leprae. A variety of experimental conditions were employed to validate this technique. This technique was also used to correlate the viability of M. leprae with the course of athymic mouse foot pad infection to optimize the provision of viable M. leprae as a research reagent. The data show that in untreated suspensions of M. leprae there is a good correlation between the metabolic activity of leprosy bacilli and their membrane damage. Fixation of M. leprae with ethanol, paraformaldehyde and gluteraldehyde completely suppressed their metabolic activity but showed little effect on their membrane integrity. The present study also showed that the metabolic activity of M. leprae declines more than the extent of membrane damage at 37 °C within 72 h, but that they are not significantly affected at 33 °C. Irradiation at 104 Gy showed high numbers of dead bacilli by the staining method. The results show that the reliability of metabolic-activity data as well as viability-staining data is dependent on the method by which M. leprae is killed. This staining method helped us predict reliably that the smaller M. leprae-infected athymic mouse foot pad seen early in infection, between 4 and 5 months, yields markedly better quality leprosy bacilli than older, larger foot pad infections, as defined by their metabolic activity and membrane integrity.

Evaluation of Membrane Damage Sensitivity by Defect Types for Improving Reliability of Membrane Integrity Monitoring

2017 ◽  
Vol 27 (3) ◽  
pp. 248-254 ◽  
Author(s):  
Yong-Soo Lee ◽  
◽  
Ha-Young Kang ◽  
Hyung-Soo Kim ◽  
Jong-Oh Kim
Keyword(s):  
Membrane Damage ◽  
Membrane Integrity ◽  
Integrity Monitoring

scholarly journals Flow Cytometric Assessment of Membrane Integrity of Ethanol-Stressed Oenococcus oeni Cells

2002 ◽  
Vol 68 (12) ◽  
pp. 6087-6093 ◽  
Author(s):  
M. Graça da Silveira ◽  
M. Vitória San Romão ◽  
Maria C. Loureiro-Dias ◽  
Frans M. Rombouts ◽  
Tjakko Abee
Keyword(s):  
Fluorescent Dyes ◽  
Membrane Damage ◽  
Flow Cytometric Analysis ◽  
Membrane Integrity ◽  
Oenococcus Oeni ◽  
Starter Cultures ◽  
Ethanol Stress ◽  
Intact Cells ◽  
Flow Cytometric ◽  
Ethanol Toxicity

ABSTRACT The practical application of commercial malolactic starter cultures of Oenococcus oeni surviving direct inoculation in wine requires insight into the mechanisms involved in ethanol toxicity and tolerance in this organism. Exposure to ethanol resulted in an increase in the permeability of the cytoplasmic membrane, enhancing passive proton influx and concomitant loss of intracellular material (absorbing at 260 nm). Cells grown in the presence of 8% (vol/vol) ethanol revealed adaptation to ethanol stress, since these cells showed higher retention of compounds absorbing at 260 nm. Moreover, for concentrations higher than 10% (vol/vol), lower rates of passive proton influx were observed in these ethanol-adapted cells, especially at pH 3.5. The effect of ethanol on O. oeni cells was studied as the ability to efficiently retain carboxyfluorescein (cF) as an indicator of membrane integrity and enzyme activity and the uptake of propidium iodide (PI) to assess membrane damage. Flow cytometric analysis of both ethanol-adapted and nonadapted cells with a mixture of the two fluorescent dyes, cF and PI, revealed three main subpopulations of cells: cF-stained intact cells; cF- and PI-stained permeable cells, and PI-stained damaged cells. The subpopulation of O. oeni cells that maintained their membrane integrity, i.e., cells stained only with cF, was three times larger in the population grown in the presence of ethanol, reflecting the protective effect of ethanol adaptation. This information is of major importance in studies of microbial fermentations in order to assign bulk activities measured by classical methods to the very active cells that are effectively responsible for the observations.

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