Effect Of Different Stress Conditions Research Articles

Comprehensive Stress Stability Studies Reveal the Prominent Stability of the Liquid-Formulated Biotherapeutic Asymmetric Monovalent Bispecific IgG1 Monoclonal Antibody Format

The developed asymmetric monovalent bispecific IgG1 or Duet monoclonal antibody (Duet mAb) has two distinct fragment antigen-binding region (Fab) subunits that target two different epitope specificities sequentially or simultaneously. The design features include unique engineered disulfide bridges, knob-into-hole mutations, and kappa and lambda chains to produce Duet mAbs. These make it structurally and functionally complex, so one expects challenging developability linked to instability, degradation of products and pathways, and limited reports available. Here, we have treated the product with different sources of extreme stress over a lengthy period, including varying heat, pH, photo stress, chemical oxidative stress, accelerated stress in physiological conditions, and forced glycation conditions. The effects of different stress conditions on the product were assessed using various analytical characterization tools to measure product-related substances, post-translational modifications (PTMs), structural integrity, higher-order disulfide linkages, and biological activity. The results revealed degradation products and pathways of Duet mAb. A moderate increase in size, charge, and hydrophobic variants, PTMs, including deamidation, oxidation, isomerization, and glycation were observed, with most conditions exhibiting biological activity. In addition, the characterization of fractionated charge variants, including deamidated species, showed satisfactory biological activity. This study demonstrated the prominent stability of the Duet mAb format comparable to most marketed mAbs.

Effects of different stress conditions on the production, bioactivities, physicochemical and structural characteristics of exopolysaccharides synthetized by Schleiferilactobacillus harbinensis Z171

This study systematically investigated the effects of stress conditions including temperature, pH, H2O2, NaCl, antibiotics on the production and in vitro cholesterol-lowering activity of the exopolysaccharide (EPS) synthetized by Schleiferilactobacillus harbinensis Z171. Additionally, the influences of the optimal stress condition combined with different carbon sources on EPS production were examined, shedding light on the structural characteristics, physicochemical properties and bioactivities of EPSs. The results demonstrated that the EPS produced under H2O2 stress was optimal and presented excellent resistance to simulated gastric juice and α-amylase. Three main fractions, denoted as G-EPS1, F-EPS1 and S-EPS1, were isolated by cellulose DEAE-52 chromatography from crude EPSs synthetized using glucose, fructose and sucrose as carbon sources, respectively. Among them, F-EPS1 possessed the highest cholesterol-lowering, antioxidant and hypoglycemic activities, with the highest molecular weight 91.03 kDa, largest particle size 40.14 nm and apparent viscosity 288.2 mPa·s. Three EPSs exhibited irregular sheet-like and granular structures with good thermal stability. Structural characterization of F-EPS1a (a purified fraction from F-EPS1) revealed that it was a mannan mainly composed of →2)-α-D-Manp-(1→, →3)-α-Manp-(1→ and →2,6)-α-D-Manp-(1→ with branch chains containing α-D-Manp-(1→. F-EPS1a has more potential to be a natural cholesterol-lowering, hypoglycemic and antioxidant supplements in the food industry.

Effect of different stress conditions on the formation of amino acid derivatives by Brewer’s and Baker’s yeast during fermentation

The effects of environmental stresses on the formation of amino acid derivatives by Saccharomyces cerevisiae NCYC 88 and Saccharomyces cerevisiae NCYC 79 were investigated. Fermentation was performed in model systems under different temperature, pH, alcohol, phenolic, and osmotic stress conditions, as well as in beer and dough. According to stress response molecules, yeasts were more affected by osmotic, temperature, and alcohol stresses. Both yeast strains increased the formation of kynurenic acid, tryptophan ethyl ester, tryptophol, and gamma-aminobutyric acid under osmotic stress conditions in model systems. Indole-3-acetic acid was found to be higher in the ferulic acid stress dough (262 µg/kg dry weight, d.w.) compared to the control dough (132 µg/kg d.w.) at the end of the fermentation. The results may enable the development of new strategies for designing novel foods with a desired composition of bioactive amino acid derivatives.

Transcriptome analysis of the biofilm formation mechanism of Vibrio parahaemolyticus under the sub-inhibitory concentrations of copper and carbenicillin

Biofilm formation of Vibrio parahaemolyticus enhanced its tolerance to the environment, but caused many serious problems to food safety and human health. In this paper, the effects of copper and carbenicillin (CARB) stress on the formation of the biofilms of V. parahaemolyticus organisms were studied, and RNA sequencing technology was used to compare the differences in transcriptome profiles of the biofilm-related genes of V. parahaemolyticus organisms under different sub-inhibitory stresses. The results proved that V. parahaemolyticus had a large growth difference under the two stresses, copper and CARB at 1/2 minimal inhibitory concentration (MIC), and it could form a stable biofilm under both stress conditions. The amount of biofilm formed under CARB stress was significantly higher than that of copper stress (p < 0.05). Based on the analysis of transcriptome sequencing results 323, 1,550, and 1,296 significantly differential expressed genes were identified in the three treatment groups namely 1/2 MIC CARB, Cu2+, and Cu2++CARB. Through COG annotation, KEGG metabolic pathway analysis and gene expression analysis related to biofilm formation, the functional pathways of transcriptome changes affecting V. parahaemolyticus were different in the three treatment groups, and the CARB treatment group was significantly different from the other two groups. These differences indicated that the ABC transport system, two-component system and quorum sensing were all involved in the biofilm formation of the V. parahaemolytic by regulating flagellar motility, extracellular polysaccharides and extracellular polymer synthesis. Exploring the effects of different stress conditions on the transcriptome of V. parahaemolyticus could provide a basis for future research on the complex network system that regulates the formation of bacterial biofilms.

Promoting of abiotic stress–induced resistance using Poly-β-Hydroxybutyrate (PHB) by Rhizobium phaseoli in common bean plants.

In total, 50 Rhizobium isolates were isolated from the mature root nodules of common beans plants (Phaseolus vulgaris) grown in different nine governorates of Egypt. PHB was optimized by the identified strain using response surface methodology. A total of 11 parameters (pH, incubation period, inoculum size, temperature, agitation speed, mannitol, sucrose, yeast extract, glycine, K2HPO4, and MgSO4) were analyzed for their significant effects on PHB production by the Plackett–Burman design (PBD). Sucrose, yeast extract, glycine, and MgSO4 were the main significant factors affecting PHB accumulation. Central composite design (CCD) of the response surface methodology was used to determine the optimum levels of the selected factors. Rhizobium phaseoli reached the maximum production (4.997 g/L) at run 36 in the presence of 25 g/L of sucrose, 0.0 g/L of yeast extract, 0.87 g/L of glycine, 0.3 g/L of MgSO4, and 5% of inoculation size. In vitro experiments were carried out to test the effect of different stress conditions (pH: 6–11, temperature: 5°C–50°C, salinity: 0.01%–7%, and drought: 0%–5% w/v) on the growth of Rhizobium phaseoli. The results showed that Rhizobium phaseoli can withstand 3% –5% NaCl, high temperature of 30°C– 45°C, alkalinity at pH value of 8 – 10, and drought stress at 3% – 5% w/v polyethylene glycol with growth loss of 50% when grown on modified medium and 75% when grown on the basal one. In vivo experiments were done to study the effect of drought stress levels on the growth parameters of common bean plants. In general, all the treatments with Rhizobium phaseoli grown on the modified medium were superior to Rhizobium phaseoli grown on the basal medium. Also, they showed high tolerance of drought conditions.

Effect of Stress on Creep Behavior of Single Crystal Alloy IC6SX at 980°C

Ni3Al-based single crystal alloy IC6SX was prepared by seed crystal method. The effect of different stress conditions on creep behavior of this alloy at 980°C was investigated. The results showed that the creep life of this alloy at 980°C decreased significantly with the increase of stress. When the stress increased from 180 MPa to 230 MPa, the creep life dropped from 245.5 h to 69.3 h, and the steady-state creep rate increased slightly but not significantly. Meanwhile, the morphology of γ ′ phase and dislocation after creep were studied. The results showed that with the increase of stress, the density of dislocations in the γ ′ phase increased gradually, the strength of this alloy decreased gradually, so the creep life decreased significantly. The Y-NiMo phase resolved from the γ phase decreased gradually as the creep life decreased. The creep experiment of the alloy was carried out at 980°C. Due to the higher temperature, the diffusion of atoms in this alloy became faster. Deformation was not only caused by the slippage of dislocations in the crystal but also by the diffusion of atoms. Therefore, the creep mechanism of single crystal alloy IC6SX at this temperature is a mixed mechanism of dislocation glide and diffusion.

The acceleration effect of different stress conditions on the accelerated life test of LED driver

LED driver is the key component of LED lighting system, the damage of the driver will cause the failure of the whole lamp, but there is no specific test method for accelerated life test of LED driver at the system level. In order to study the acceleration effect of different stress conditions, research on the principle of LED driver, select different stress application conditions according to different electrical topology. In order to ensure that the stress does not affect the normal operation of the driver, and the failure mode or failure mechanism will not be changed, it is necessary to carry out the limit stress test before designing the test scheme. The results show that the acceleration effect is significant under the condition of constant temperature humidity or constant temperature humidity voltage compound stress, moreover, the acceleration effect is not obvious under the condition of single constant temperature or constant humidity temperature cyclic stress. The accelerated life model of LED driver is established, and the linear fitting is carried out by Weibull distribution and least square method, the variable parameters in the model are derived from the experimental data, and the accelerated life test method will be further studied.

Effect of different stress conditions on the vegetative growth of the filamentous fungus Acremonium chrysogenum.

El hongo filamentoso Acremonium chrysogenum produce una mezcla de sustancias antibióticas, entre las que destaca la cefalosporina C. Con una participación de mercado del 50% para la cefalosporina C y sus derivados semisintéticos, desempeñan un importante rol en la industria farmacéutica. Debido a su amplio espectro de efectividad contra las bacterias Gram (+) y Gram (-), la cefalosporina C es un fármaco importante, producido únicamente por A. chrysogenum. Las condiciones ambientales inducen adaptaciones en los seres vivos, que responden modificando sus procesos biológicos para lograr su supervivencia. Estas respuestas pueden evaluarse in vitro para dilucidar el efecto del estrés fisiológico en el desarrollo. De esta manera, en este trabajo se evaluó el efecto de diferentes osmolitos, del peróxido de hidrógeno y la luz blanca sobre el crecimiento vegetativo de A. chrysogenum. Se observó un incremento del crecimiento de A. chrysogenum en condiciones de NaCl 0,5 M, mientras que frente al KCl fue osmosensible, deduciéndose una osmoadaptación al NaCl. El glicerol solamente mostró efectos inhibidores del crecimiento a concentraciones de 1M. Por otro lado, A. chrysogenum presentó tolerancia al estrés oxidativo inducido por el peróxido, incluso a concentraciones de 100 mM. Finalmente, un fotoperíodo LD (12/12) estimuló el desarrollo del hongo, mientras que en condiciones LL la tasa de crecimiento fue similar a la observada en la condición de control (DD).Palabras clave: Acremonium chrysogenum, estrés osmótico, estrés oxidativo, estrés lumínico.

Analysis on mechanical influencing factors of fatigue behavior for the packer on pipe ram in snubbing unit

In snubbing service, the ram blowout preventer (BOP) is switched frequently, and the stress condition of the packer is very complicated. Cracks, rubber drop, and other fatigue failures often occur. The load characteristic was firstly analyzed in this paper based on the stress condition of packer in snubbing service. The mechanical property of rubber commonly used for packer was tested, and the performance parameters were obtained. Based on the crack initiation approach, taking the rubber matrix as the research object, the effective stress, the maximum Green–Lagrange strain and strain energy density were selected as damage parameters. The distribution contour of three damage parameters of the rubber matrix of the packer under different stress conditions and speeds of lifting or lowering pipe were obtained using finite element method (FEM). The effect of different stress conditions and speeds of lifting or lowering pipe on the fatigue behavior for the rubber matrix was analyzed. The result shows that the value of three damage parameters is relatively high on the upper area of the rubber matrix, causing the first occurrence of fatigue in the upper part, which agrees well with the oilfield application. The speed of the pipe does not change the location of fatigue point and the value of damage parameters, so that it has little effect on the fatigue behavior of the packer's rubber matrix. Finally, based on Miner linear damage rule, a calculation method for the fatigue behavior of the packer is presented.

Investigation on Creep Properties of Welded Joint of Modified 9Cr-1Mo Martensitic Heat-Resistant Steel

The creep rupture behavior of weld joint of modified 9Cr-1Mo martensitic heat-resistant steel is investigated by conducting creep tests. The creep strain-time curves of 838K under different stress levels are obtained. The effects of different stress conditions on the creep rupture lifetime are analyzed. Based on the creep test data, the relationship between minimum creep rate and stress, creep rupture time is analyzed. The test results show that the creep rupture occurred in the fine-grained heat-affected zone. The microstructure evolution during creep process is studied by metallographic analysis and fracture analysis.

Soil Water Characteristic Curve of an Unsaturated Soil under Low Matric Suction Ranges and Different Stress Conditions

Accurate evaluation of unsaturated soil properties is critical for the design of geotechnical and geo-environmental structures such as road pavements, foundations, and earth dams. Water retention activity in soils which is used to predict the stability or seepage problems in the ground is one of the key features in unsaturated soil mechanics. Thus, many experimental works have reported on the unsaturated soil properties, and the soil-water characteristic curve (SWCC) test has contributed significantly to the interpretation of matric suction. Since traditional instruments cannot apply stress in SWCC tests, some researchers have developed suction controlled triaxial apparatus, by which SWCC tests are performed under different stress states. Determination of SWCCs under stress conditions similar to those in the field is key for interpretation of the hydro-mechanical behavior of unsaturated soils. This study conducted SWCC tests of unsaturated silt soil in low matric suction ranges under both drying and wetting conditions. The SWCCs were measured under one-dimensional and isotropic confining stresses ranging from 50 to 450 kPa. The micro porous membrane method was used instead of high air entry ceramic disk for controlling relatively low matric suction. The range of matric suction controlled was from 0 to 20 kPa. The study revealed that the measured SWCC in low matric suction ranges seems to be affected by the influence of stress conditions. Isotropic confining stress caused the void structure of the specimen to become dense and consequently, soil moisture flow movement also decreased. The water retention activity was obviously high, and the point regard to air entry value was larger. The study further suggests that the current methods adopted for estimating unsaturated soil properties require further development to take into account the effect of different stress conditions.

Comparison of Soil–Water Characteristic Curves in One-Dimensional and Isotropic Stress Conditions

Understanding unsaturated soil behavior is key to the design of foundations and embankment structures. Geotechnical engineers have applied net normal stress and matric suction to these engineering problems. Water retention activity in soils is used to predict seepage problems and stability of slope failures. Soil–Water Characteristic Curve (SWCC) tests contribute largely to matric suction interpretation. Determination of SWCCs in the laboratory is usually done using a pressure plate apparatus where vertical or confining stress cannot be applied. Mathematical models of SWCC though commonly accepted in geotechnical engineering practices, do not take into consideration stress conditions such as the difference between a one-dimensional condition and isotropic confining conditions. This study conducted SWCC tests of a silt soil under one-dimensional and isotropic confining stress conditions and focused on the differences between these types of SWCC data sets. Vertical and isotropic confining stresses ranging from 100 to 600 kPa were applied under both stress conditions. SWCCs appears to be affected by the influence of different stress conditions. Lateral pressure and confinement on an isotropic compression condition caused the soil specimen to become dense in void structure and consequently, soil moisture flow movement decreased. This probably induced high retention activities in the silt soil specimen. The study further suggests that the current SWCC models require further development to take into consideration the effect of different stress conditions.

Research on the Impacts of Time—Anticipatory Stress on Creativity

This paper applies natural experiment to research on 120 college students, recording their performances of creativity under different time and anticipatory stress conditions. By using SPSS software to deal with the results of experiments, effects of different stress conditions on one’s creativity performance have been studied. The conclusions indicate that, under higher-time stress, the creativity performance is much more considerable with higher anticipations; under lower-time stress, the performance of creativity stays stable no matter how the level of anticipation is; under lower-time stress, the performance of creativity is much higher than that in higher-time stress, in spite of level of anticipations; under lower-time and higher-anticipatory stress, the level of creativity is the highest; under lower-time and higher-anticipatory stress, the flexibility of creativity is the most considerable; under lower time stress, the fluency and peculiarity is remarkable than that in higher-time-stress condition. Therefore, when facing plenty of tasks during work, employees and managers should judge the emergency and importance of theses work as well as control and arrange the finishing time and speed reasonably, which is helpful to deal with these problems.

Effects of environmental stress on seed germination and seedling growth of Salsola ferganica (Chenopodiaceae)

Plant growth and development are usually influenced by salt, drought, high or low temperature, strong illumination and other adverse factors, which may finally threaten the settlement and propagation of the species. Studies on seed germination behavior and seedling growth of annual halophyte plant living in harsh environment can help us to thoroughly understand the tolerance mechanism of desert plants. Salsola ferganica, an annual halophyte living in extreme desert habitat, has special morphological structure and characteristics in tolerance of stress. In the present study, we discussed the effects of different stress conditions, such as light, day/night temperature variation, salt (NaCl) and drought (PEG 6000), etc. on seed germination (SG) and seedling growth (SGr) of S. ferganica. Results showed that: (1) Light had a positive effect, while darkness had a negative effect on SG, which indicates that seed germination of S. ferganica depends on and is sensitive to light. (2) Monthly examination of SG from 2014 to 2015 showed that SG of seed without winged perianth (NWP) was apparently higher than seed with winged perianth (WWP) stored at room temperature (RT) or 4°C. For WWP seeds, SG in light was significantly higher than that in darkness; SG also varied among seasons: in Spring, SG of seeds stored at RT was the lowest and so did it in summer with seeds stored at 4°C. SG of seeds stored at both temperatures had no significant difference at the same month. Seed vigor agreed with SG behavior partly and there was no obvious difference between months. (3) The day/night temperature variation (D/NTV) applied significant effect on SG and SGr. SG decreased at lower D/NTV (e.g. 5°C/15°C) but increased at middle and higher D/NTV (e.g. 10°C/20°C, 15°C/25°C, 20°C/30°C) in light. In darkness, the SG decreased at higher D/NTV (e.g. 15°C/25°C, 20°C/30°C) but increased at lower and middle D/NTV (e.g. 5°C/15°C, 10°C/20°C). 10°C/20°C D/NTV had positive effect on SG in both light and darkness; germination rate was promoted at higher D/NTV in both light and darkness. SGr was promoted at lower D/NTV while inhibited at higher D/NTV. (4) SG at lower concentration of NaCl (<100mmolL−1, osmotic pressure (OP)≥−500kPa) and PEG (<150gL−1, OP≥−300kPa) was similar to the control (OP 0kPa); however SG at higher concentration of NaCl (≥500mmolL−1, OP<−2478kPa) and PEG (≥200gL−1, OP<−300kPa) significantly decreased but still exceeded 35%, indicating that S. ferganica is salt- and drought-tolerant. When considered of the SG between NaCl and PEG treatment at the same level of OP, which was much better with NaCl than that with PEG. Taken together, we speculate that S. ferganica should employ ‘cautious strategy’ in germination, which means that under favorable conditions with light, temperature, water, etc., S. ferganica can germinate actively and get enough seedlings developing into adult plants; whereas under unfavorable conditions, the seeds may not germinate or germinate in a small amount to replenish soil seed bank.

Effect of different stress conditions on the stability of quercetin-loaded lipid microparticles produced with babacu ( Orbignya speciosa ) oil: evaluation of their potential use in food applications

Lipid micro and nanoparticles have been extensively investigated as carriers for hydrophobic bioactives in food systems because they can simultaneously increase the dispersibility of these lipophilic substances and help improve their bioavailability. In this study, lipid microparticles of babacu oil and denatured whey protein isolate were produced, and their ability to protect quercetin against degradation was evaluated over 30 days of storage. Additionally, the lipid microparticles were subjected to the typical stress conditions of food processing (presence of sucrose, salt, and thermal stresses), and their physico-chemical stability was monitored. The data show that the babacu microparticles efficiently avoided the oxidation of quercetin because 85% of the initial amount of the flavonoid was preserved after 30 days. The particles were notably stable up to a temperature of 70 °C for 10 minutes at relatively high concentrations of salt and sucrose. The type of stirring (mechanical or magnetic) also strongly affected the stability of the dispersions.

The use of comet assay in plant toxicology: recent advances.

The systematic study of genotoxicity in plants induced by contaminants and other stress agents has been hindered to date by the lack of reliable and robust biomarkers. The comet assay is a versatile and sensitive method for the evaluation of DNA damages and DNA repair capacity at single-cell level. Due to its simplicity and sensitivity, and the small number of cells required to obtain robust results, the use of plant comet assay has drastically increased in the last decade. For years its use was restricted to a few model species, e.g., Allium cepa, Nicotiana tabacum, Vicia faba, or Arabidopsis thaliana but this number largely increased in the last years. Plant comet assay has been used to study the genotoxic impact of radiation, chemicals including pesticides, phytocompounds, heavy metals, nanoparticles or contaminated complex matrices. Here we will review the most recent data on the use of this technique as a standard approach for studying the genotoxic effects of different stress conditions on plants. Also, we will discuss the integration of information provided by the comet assay with other DNA-damage indicators, and with cellular responses including oxidative stress, cell division or cell death. Finally, we will focus on putative relations between transcripts related with DNA damage pathways, DNA replication and repair, oxidative stress and cell cycle progression that have been identified in plant cells with comet assays demonstrating DNA damage.

Proteomic Studies of the Effects of Different Stress Conditions on Central Carbon Metabolism in Microorganisms

The ability of cells to respond rapidly to fluctuations in environmental conditions such as thermal stress, pH, hypoxia, exposure to radiation, chemicals and a number of other factors is important for competitive fitness, adaptation and cell survival. To understand the dynamics of the complex metabolic pathways involved, various approaches including genomics, transcriptomics, proteomics, metabolomics, kinetics and biochemical information are appropriate. Proteomics is useful for evaluating the expression profiles of proteins, their post-translational modification and interactions between molecules. This review summarizes recent proteomics data examining the effects of different stress conditions on central carbon metabolism (CCM) in microorganisms. Data, primarily on enzymes involved in glycolysis, the tricarboxylic acid cycle and pentose phosphate pathways, were extracted from various sources, analyzed and are presented herein. Many proteomics analyses show that particular stress conditions affect the expression of specific enzymes of CCM or their pathways. Taken together, proteomic studies provide both an opportunity and a challenge for the study of the global regulation of CCM protein expression, posttranslation control of enzymes, and consequently the global regulation of enzymes under different stress conditions.

Induction of somatic embryogenesis as an example of stress-related plant reactions

In this review, we address the role of stress as one of the principal causes for a cell or tissue to change its pre-existing somatic program, reprogramming itself to express the embryogenic pathway. The focus of this paper is the effect of different stress conditions on the induction phase of plant somatic embryogenesis, as well as the development of embryogenic competence as a result of the applied stresses. We also present a variety of data that link plant somatic embryogenesis, DNA methylation and oxidative stress response.

Flocculation onset in Saccharomyces cerevisiae: effect of ethanol, heat and osmotic stress

To examine the effect of different stress conditions on the onset of flocculation in an ale-brewing strain, Saccharomyces cerevisiae NCYC 1195. Flocculation was evaluated using the method of Soares, E.V. and Vroman, A. [Journal of Applied Microbiology (2003) 95, 325]; plasma membrane integrity was accessed using propidium iodide and the staining of the yeast cell wall was performed using calcofluor white M2R. Cells in exponential phase of growth were subjected to different stress conditions. The addition of 1%, 3% and 5% (v/v) ethanol, 1% and 3% (v/v) isopropanol or a brief heat shock (52 degrees C, 5 min), did not induce an early flocculation phenotype when compared with control cells. The addition of 10% (v/v) ethanol, a continuous mild heat-stress (37 degrees C) or an osmotic stress (0.5 or 1 mol l(-1) of NaCl) did not induce a flocculent phenotype. Flocculation seems not to be induced as a response to different chemical (ethanol and isopropanol) and physical (heat and osmotic) stress conditions. Conversely, osmotic and ethanol [10% (v/v)] stress, as well as a continuous mild heat shock (37 degrees C), have a negative impact on the phenotype expression of flocculation. The findings reported here contribute to the elucidation of the control of yeast flocculation. This information might be useful to the brewing industry, as the time when the onset of flocculation occurs can determine the fermentation performance and the beer quality, as well as in other biotechnological industries where flocculation can be used as a cell separation process.

Effect of stress conditions on Escherichia coli outer and inner membranes, separated by sephacryl S-500 chromatography

A chromatographic method for the separation of outer and inner membranes of Escherichia coli is described. This method is much faster than the generally used equilibrium centrifugation and has a greater versatility in the volumes that can be treated. Both techniques are used to examine the effects of different stress conditions on the E. coli membrane. The obtained results illustrate the equivalence of both methods.