High NaCl Concentrations Research Articles

Effect of salinity on glandular trichomes density, phenolic and flavonoid contents of Morus spp. accessions leaves from Indonesia

The density of glandular trichomes and metabolite compounds in plants can increase under salt stress. Information about the glandular trichomes density described tolerance to salt stress however, there is no information about it in mulberry. This study aimed to obtain accessions of mulberry that are tolerant to NaCl concentrations based on cystolith trichome density, glandular trichome density, and phenolic and flavonoid content. Mulberry stem cuttings were planted using a factorial randomized block design with 3 replications. The first treatment used was seven mulberry accessions, which come from 5 regions in Indonesia (Bali, Makassar, Pati, Situbondo, and Bogor), and the second was the NaCl concentration (0.0%, 0.2%, 0.3%, and 0.4%). The results showed that the highest cystolith trichomes density was obtained in M2 accession (32.5 cells/mm2 from the highest NaCl concentration). The highest density of the glandular trichomes was obtained in the M4 accession (50 cells/mm2 from the highest NaCl concentration). The highest phenolic and flavonoid contents were obtained in the M4 accession (154.6 mg GAE/g extract for 0.3% concentration of NaCl) and M2 accession (619.56 mg QE/g extract for the highest concentration of NaCl), respectively. The study concluded that the M2 (accession from Bogor) is tolerant to salt stress.

Pemurnian Garam Rakyat Menjadi Garam Industri dengan Alat Hidroekstraktor

Garam rakyat (krosok) yang ada di Indonesia dapat dimanfaatkan menjadi garam industri dengan meningkatkan kemurniannya. Penelitian ini bertujuan untuk membuat garam industri dari garam rakyat dengan menggunakan alat hidroekstraktor. Penelitian ini juga bertujuan untuk mengetahui pengaruh variabel jumlah pencucian, perbandingan feed dan solvent terhadap kadar NaCl dan %losses yang dihasilkan. Penelitian ini mengaplikasikan metode hi-droekstraksi dalam proses pemurnian garam rakyat. Metode hidroekstraksi mampu memisahkan pengotor dalam garam rakyat dengan menggunakan larutan garam jenuh sehingga garam yang dihasilkan lebih murni. Pembuatan garam industri dilakukan dengan menggunakan hidroekstraktor yang dilengkapi motor pengaduk berupa screw se-bagai tempat terjadinya ekstraksi antara garam rakyat dan larutan garam jenuh sesuai variabel yang sudah diten-tukan. Hasil analisa menunjukkan kadar NaCl tertinggi yaitu pada perbandingan feed dan solvent 3:3 dengan 3 kali pencucian yaitu sebesar 95.6%, sedangkan kadar NaCl terendah yaitu pada perbandingan feed dan solvent 2:4 dengan 1 kali pencucian yaitu sebesar 84.6%.

Osmolytes and Lipids of the Conidia of the Xerohalophilic Micromycete <i>Aspergillus penicillioides</i>

Abstract—Investigation of the lipid and osmolyte composition in conidia of the xerohalophile Aspergillus penicilloides grown on media with high concentrations of NaCl and glycerol is important for the understanding of the functions of these compounds in the adaptation of the extremophile. Conidia of the fungus grown on a medium with glycerol contained up to 15% of the dry mass of carbohydrates and polyols (CaP) of the cytosol, with predominance of glycerol (60% of the total) in their composition, while on a medium with salt, the proportion of glycerol did not exceed 20%, and the amount of CaP was 10%. On both media, the proportion (20%) and amount (2.5%) of trehalose were the same; the proportion of polyols was thus about 80%, although their composition was different, indicating a possible synergy between trehalose and polyols in adaptation. Both variants of conidia were characterized by a low content of both membrane and storage lipids, represented mainly by triacylglycerides. Phosphatidylcholines and sterols were the predominant membrane lipids of the fungal conidia, regardless of the composition of the medium, which indicated high stability and conservatism of the lipid bilayer. The constancy of the composition of membrane and storage lipids and their low content, the high level of CaP, and significant differences in their composition indicate the key role of osmolytes in the adaptation of fungal conidia to various environmental conditions.

Overexpression of a C3HC4‐type E3‐ubiquitin ligase contributes to salinity tolerance by modulating Na+ homeostasis in rice

AbstractSoil salinity has a negative effect on crop yield. Therefore, plants have evolved many strategies to overcome decreases in yield under saline conditions. Among these, E3‐ubiquitin ligase regulates salt tolerance. We characterized Oryza sativa Really Interesting New Gene (RING) Finger C3HC4‐type E3 ligase (OsRFPHC‐4), which plays a positive role in improving salt tolerance. The expression of OsRFPHC‐4 was downregulated by high NaCl concentrations and induced by abscisic acid (ABA) treatment. GFP‐fused OsRFPHC‐4 was localized to the plasma membrane of rice protoplasts. OsRFPHC‐4 encodes a cellular protein with a C3HC4‐RING domain with E3 ligase activity. However, its variant OsRFPHC‐4C161A does not possess this activity. OsRFPHC‐4‐overexpressing plants showed enhanced salt tolerance due to low accumulation of Na+ in both roots and leaves, low Na+ transport in the xylem sap, high accumulation of proline and soluble sugars, high activity of reactive oxygen species (ROS) scavenging enzymes, and differential regulation of Na+/K+ transporter expression compared to wild‐type (WT) and osrfphc‐4 plants. In addition, OsRFPHC‐4‐overexpressing plants showed higher ABA sensitivity under exogenous ABA treatment than WT and osrfphc‐4 plants. Overall, these results suggest that OsRFPHC‐4 contributes to the improvement of salt tolerance and Na+/K+ homeostasis via the regulation of changes in Na+/K+ transporters.

A New Natural Processing System Based on Slight Carbon Dioxide Pressure for Producing Black Table Olives with Low Salt Content.

Naturally fermented black table olives are usually processed in brine with low pH and high NaCl content. Because salt is responsible for several cardiovascular problems, methods are needed to decrease the salt (NaCl) content in olive pulp. This study investigated a new natural processing system wherein microorganism growth is inhibited by slight pressure of CO2 (spCO2), in addition to low pH and NaCl, in brine with decreased salt content. The fermentation performed under spCO2 with a low-salt brine with 6% (w v-1) NaCl and 0.5% (w v-1) citric acid, unlike the traditional system, inhibited the growth of bacteria and fungi and decreased the concentration of yeasts. Processing tests with spCO2 in the presence of different salt and citric acid concentrations indicated a slight decrease in yeasts in brines containing 6% (w v-1) NaCl and 0.6% (w v-1) citric acid but not after inoculation of the same brines with Saccharomyces cerevisiae. In contrast, in the presence of 11% (w v-1) NaCl and 0.3% or 0.6% (w v-1) citric acid, the inhibitory effect of brines was greater compared to those with low-salt and it was also confirmed in the same brines inoculated with S. cerevisiae.

Comparing polymer-surfactant complexes to polyelectrolytes

HypothesisUnderstanding the complex interactions between polymers and surfactants is required to optimise commercially relevant systems such as paint, toothpaste and detergent. Neutral polymers complex with surfactants, forming ‘pearl necklace’ structures that are often conceptualised as pseudo-polyelectrolytes. Here we pose two questions to test the limits of this analogy: Firstly, in the presence of salt, do these polymer-surfactant systems behave like polyelectrolytes? Secondly, do polymer-surfactant complexes resist geometric confinement like polyelectrolytes? ExperimentsWe test the limits of the pseudo-polyelectrolyte analogy through studying a poly(N-isopropylacrylamide) (PNIPAM) brush in the presence of sodium dodecylsulfate (SDS). Brushes are ideal for interrogating pseudo-polyelectrolytes, as neutral and polyelectrolyte brushes exhibit distinct and well understood behaviours. Spectroscopic ellipsometry, quartz crystal microbalance with dissipation monitoring (QCM-D), and neutron reflectometry (NR) were used to monitor the behaviour and structure of the PNIPAM-SDS system as a function of NaCl concentration. The ability of the PNIPAM-SDS complex to resist geometric confinement was probed with NR. FindingsAt a fixed SDS concentration below the zero-salt CMC, increasing NaCl concentration <100 mM promoted brush swelling due to an increase in osmotic pressure, not dissimilar to a weak polyelectrolyte. At these salt concentrations, the swelling of the brush could be described by a single parameter: the effective CMC. However, at high NaCl concentrations (e.g., 500 mM) no brush collapse was observed at all (non-zero) concentrations of SDS studied, contrary to what is seen for many polyelectrolytes. Study of the polymer-surfactant system under confinement revealed that the physical volume of surfactant dominates the structure of the strongly confined system, which further differentiates it from the polyelectrolyte case.

A comprehensive investigation of protein expression profiles in L. monocytogenes exposed to thermal abuse, mild acid, and salt stress conditions.

Preventing L. monocytogenes infection is crucial for food safety, considering its widespread presence in the environment and its association with contaminated RTE foods. The pathogen's ability to persist under adverse conditions, for example, in food processing facilities, is linked to virulence and resistance mechanisms, including biofilm formation. In this study, the protein expression patterns of two L. monocytogenes 1/2a strains, grown under environmental stressors (mild acidic pH, thermal abuse, and high concentration of NaCl), were investigated. Protein identification and prediction were performed by nLC-ESI-MS/MS and nine different bioinformatic software programs, respectively. Gene enrichment analysis was carried out by STRING v11.05. A total of 1,215 proteins were identified, of which 335 were non-cytosolic proteins and 265 were immunogenic proteins. Proteomic analysis revealed differences in protein expression between L. monocytogenes strains in stressful conditions. The two strains exhibited unique protein expression profiles linked to stress response, virulence, and pathogenesis. Studying the proteomic profiles of such microorganisms provides information about adaptation and potential treatments, highlighting their genetic diversity and demonstrating the utility of bioinformatics and proteomics for a broader analysis of pathogens.

Exploring the Profile Contributions in Meyerozyma guilliermondii YB4 under Different NaCl Concentrations Using GC-MS Combined with GC-IMS and an Electronic Nose.

Using Meyerozyma guilliermondii YB4, which was isolated and screened from southern Sichuan pickles in the laboratory, as the experimental group, we investigated the changes in growth, total ester content, and volatile flavor substances of M. guilliermondii YB4 under different NaCl concentrations. The growth of M. guilliermondii YB4 was found to be inhibited by NaCl, and the degree of inhibition increased at higher NaCl concentrations. Additionally, the total ester content of the control group (CK) was significantly lower compared to the other groups (p < 0.05). The application of NaCl also resulted in distinct changes in the volatile profile of YB4, as evidenced by E-nose results. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS) were employed to analyze the volatile compounds. A total of 148 and 86 volatiles were detected and identified using GC-MS and GC-IMS, respectively. Differential volatiles among the various NaCl concentrations in YB4 were determined by a variable importance in projection (VIP) analysis in partial least squares-discriminant analysis (PLS-DA). These differentially expressed volatiles were further confirmed by their relative odor activity value (ROAV) and odor description. Ten key contributing volatiles were identified, including ethanol, 1-pentanol, nonanal, octanal, isoamyl acetate, palmitic acid ethyl ester, acrolein, ethyl isobutanoate, prop-1-ene-3,3'-thiobis, and 2-acetylpyrazine. This study provides insights into the specificities and contributions of volatiles in YB4 under different NaCl concentrations. These findings offer valuable information for the development of aroma-producing yeast agents and the subsequent enhancement in the flavor of southern Sichuan pickles.

Response of salt stress resistance in highland barley (Hordeum vulgare L. var. nudum) through phenylpropane metabolic pathway.

Highland barley (Hordeum vulgare L. var. nudum) is a grain crop that grows on the plateau under poor and high salt conditions. Therefore, to cultivate high-quality highland barley varieties, it is necessary to study the molecular mechanism of strong resistance in highland barley, which has not been clearly explained. In this study, a high concentration of NaCl (240 mmol/L), simulating the unfavorable environment, was used to spray the treated highland barley seeds. Transcriptomic analysis revealed that the expression of more than 8,000 genes in highland barley seed cells was significantly altered, suggesting that the metabolic landscape of the cells was deeply changed under salt stress. Through the KEGG analysis, the phenylpropane metabolic pathway was significantly up-regulated under salt stress, resulting in the accumulation of polyphenols, flavonoids, and lignin, the metabolites for improving the stress resistance of highland barley seed cells, being increased 2.71, 1.22, and 1.17 times, respectively. This study discovered that the phenylpropane metabolic pathway was a significant step forward in understanding the stress resistance of highland barley, and provided new insights into the roles of molecular mechanisms in plant defense.

Probing the surface forces between air bubbles and bitumen via direct force Measurements: Effects of aqueous chemistry

The surface interactions of air bubbles and other components (e.g., particles, oil droplets) significantly influence the operation efficiency of a variety of engineering processes such as oily water treatment, bitumen extraction and flotation. Herein, the surface interactions of air bubbles with two types of Athabasca bitumen samples in aqueous solutions of varying pH, salinity, type of cations and in the presence of surfactants have been systematically characterized using a bubble probe atomic force microscope (AFM) technique. AFM imaging has revealed that exposure to high concentrations of NaCl and CaCl2 solutions or alkaline environments causes roughening of the bitumen surfaces. The results of surface force measurements demonstrate that the interaction and attachment behaviors between bubbles and bitumen are significantly affected by ionic strength, solution pH, and the presence of surfactants. The experimental force measurement results could be accurately described by a theoretical model that incorporates Reynolds lubrication theory and augmented Young-Laplace equation, with the inclusion of disjoining pressure. In low-salinity conditions, the bubble-bitumen interaction is dominated by electric double layer (EDL) repulsion, which prevents surface attachment. This effect is more pronounced at elevated pH conditions. In high-salinity solutions, however, the EDL interactions are significantly reduced, and the hydrophobic interaction becomes the dominant factor, overcoming the van der Waals repulsion and leading to the attachment of bubbles to bitumen surfaces. Raising aqueous pH weakens the bubble-bitumen hydrophobic interaction, whereas the introduction of calcium ions strengthens this interaction, resulting in enhanced surface attachment. Interestingly, even in high-salinity conditions, the presence of a small number of surfactants can inhibit bubble-bitumen contact, mainly caused by reduced hydrophobic attraction and increased steric repulsion. This work provides valuable nanoscale insights into how bubbles and bitumen interact in intricate aqueous environments, and the results show practical implications for controlling similar interfacial phenomena in various engineering processes.

Four Decades of the Comet Assay: pH Optimum of Lysis Buffer Still Needs to be Elucidated.

The proper course and reproducibility of diagnostic techniques depend on narrowly defined reaction conditions, including the reaction pH. Nevertheless, numerous assays are affected by an inaccurately defined reaction pH. Buffers are sometimes suggested for use outside their useful pH ranges, which complicates the reproducibility of results because the buffering capacity is insufficient to retain the disclosed pH. Here, we focus on the comet assay lysis buffer. Comet assay is broadly used for quantifying DNA breaks in eukaryotic cells. The most widespread comet assay protocols employ lysis of the cells before electrophoresis in a buffer containing Triton X-100, a high concentration of NaCl, sodium sarcosinate, EDTA, and Tris, with some modifications. However, nearly all researchers report that they use Tris buffer at pH 10, and some report the pH of the Tris additive alone. Alternatively, others report the pH of the final lysis buffer. However, the lysis solution used in the comet assay is buffered at a pH outside the useful range of Tris. Tris-based buffers have a useful pH range of 7.0 - 9.0. The buffer composed of 10 mM Tris has pKa 8.10 at 25°C and 8.69 at 4°C. The cell lysis conditions used in nearly all modifications of comet assay protocols remain imprecise and uncritically employed. Despite the pH of the lysis buffer likely has negligible effect on the detection of DNA breaks, precise lysis conditions are highly important for the use of comet assay in the detection of base modifications, which are often unstable and sensitive to pH.

A lesson from polybutylene succinate plastisphere to the discovery of novel plastic degrading enzyme genes in marine vibrios.

Polybutylene succinate (PBS) is an eco-friendly green plastic. However, PBS was shown as being non-biodegradable in marine environments, and up until now, only a limited number of PBS-degrading marine microbes have been discovered. We first set up in vitro PBS- and PBSA (polybutylene succinate adipate)-plastispheres to characterize novel PBS-degrading marine microbes. Microbial growth and oxygen consumption were observed in both PBS- and PBSA-plastispheres enriched with natural seawater collected from Usujiri, Hokkaido, Japan, and Vibrionaceae and Pseudoalteromonadaceae were significantly enriched on these films. Further gene identification indicated that vibrios belonging to the Gazogenes clade possess genes related to a PBS degrading enzyme (PBSase). The PBS degradation assay for six Gazogenes clade vibrios identified Vibrio ruber, Vibrio rhizosphaerae, and Vibrio spartinae as being capable of degrading PBS. We further identified the gene responsible for PBSase from the type strain of V. ruber, and the purified recombinant vibrio PBSase was found to have low-temperature adaptation and was active under high NaCl concentrations. We also provided docking models between the vibrio PBSase and PBS and PBSA units to show how vibrio PBSase interacts with each substrate compared to the Acidovorax PBSase. These results could contribute to a more sustainable society through further utilization of PBS in marine environments and plastic recycling.

The ability of two indigenous bacteria isolated from Moroccan olive tree to promote the growth of olive seedlings in the presence of the pathogen Verticillium dahliae

ABSTRACT The rhizosphere of olive trees (Olea europaea L.) is a source of bacteria with a high potential for biocontrol and plant growth promotion. In the present study, two native olive tree gram-negative bacteria were isolated from the rhizosphere of century-old trees in the region of Zouala (south-eastern Morocco), known for its arid climate and saline soils. The strains Pantoea agglomerans and Enterobacter ludwigii exhibited high tolerance to high PEG and NaCl concentrations, and significant plant growth-promoting (PGP) potential in vitro. The two strains efficiently solubilised phosphate in its two forms (TCP and RP), and Mica as a source of potassium and produced IAA. The two strains exhibited in vitro inhibition ability against Verticillium dahliae with partial inhibition of the growth of the mycelium by the strain P. agglomerans MRC_ZO_17. Greenhouse experiments showed that olive tree seedlings treated with the E. ludwigii MRC_ZO_97 strain significantly improved growth (dry weight) in the presence and absence of the pathogen compared to untreated plants, while the P. agglomerans MRC_ZO_17 strain showed significant effects on seedling growth only in the presence of the pathogen V. dahliae OV1 defoliating pathotype. Both strains showed high exopolysaccharides (EPS) production and good biofilm formation, making them excellent plant growth-promoting rhizobacteria (PGPRs) and Biological Control Agents (BCAs) with great potential to survive in soil under stress conditions.

A deep learning-enabled smartphone platform for rapid and sensitive colorimetric detection of dimethoate pesticide.

A novel deep learning-enabled smartphone platform is developed to assist a colorimetric aptamer biosensor for fast and highly sensitive detection of dimethoate. The colorimetric determination of dimethoate is based on the specific binding of dimethoate and aptamer, which leads to the aggregation of AuNPs in high-concentration NaCl solution, resulting in an obvious color change from red to blue. This color change provides sufficient data for self-learning enabled by a convolutional neural network (CNN) model, which is established to predict dimethoate concentration based on images acquired from a smartphone. To enhance user-friendliness for non-experts, the CNN model is then embedded into a smartphone app, enabling offline detection of dimethoate pesticide in real environments within just 15min using a pre-configured colorimetric probe. The developed platform exhibits superior performance, achieving a regression coefficient of 0.9992 in the concentration range of 0-10μM. Moreover, the app's performance is found to be consistent with the ELISA kit. These remarkable findings demonstrate the potential of combining colorimetric biosensors with smartphone-based deep learning methods for the development of portable and affordable tools for pesticide detection.

Effect of Chemical Mutagenesis on Salt Tolerance of Common Beans (Phaseolus vulgaris L.) Nodulating Rhizobium

The chemical mutation is one of the important factors in the enrichment of the salt resistance capacity of the rhizobium isolates. Therefore, this study focused on 10 isolates of rhizobium collected from soil samples of Babile, Hararghe region, Ethiopia. All the collected isolates turned into a moderately yellow, yellow, and deep yellow color in yeast extract mannitol agar medium (YEMA) containing bromothymol blue after 48 h of incubation. It indicated that all the isolates were acid-producing Rhizobia. Moreover, based on colony morphology and diameter, 70% of the isolates displayed large mucoid colonies, and 30% of the isolates showed large watery colonies in YEMA media. Among the 10 isolates, 9(90%), 9(90%), 6(60%), 6(60%), 2(20%), and 1(10%), were grown at different salinity levels such as 2%, 4%, 6%, 8%, 9% and 10% of NaCl, correspondingly. The most salt-resistant wild isolate was HUCR 6 collected from Babile soil grown at 10% NaCl salinity level. A total of six mutants were considered after chemical mutagenesis based on their capacity to survive in the extreme salinity levels (11 to 14%). Mutant isolates such as HUCRM 4, HUCRM 5, and HUCRM 6 were the most tolerant Rhizobium that grew at the salinity level of 11 to 14% NaCl. The most sensitive mutant isolate was HUCRM 10 followed by the isolates HUCRM 8 and HUCRM 9 was the next sensitive mutant Rhizobia that grew only at 11% of NaCl concentration. Compared to the Rhizobium wild isolates, the mutant isolates were observed to be more tolerant to a medium containing higher concentration of NaCl, as high as 11% to 14%. Besides, 80% of the mutant isolates demonstrated effective nodulation with the common beans. The mutant isolate (HUCRM 4) showed better performance in relation to root nodule performance of Rhizobium species and increased the plant biomass production. In this study, mutant isolates HUCRM 6, which is tolerated to 14% NaCl, and HUCRM 4, HUCRM 5, and HUCRM 6 isolates tolerated at 12% salinity level. Finally, based on their symbiotic efficiency and tolerance to extreme salt levels, these mutant isolates (HUCRM 4, HUCRM 5 and HUCRM 6) were encouraged to be used for the development of Rhizobium inoculants of common beans grown under extreme saline conditions. J. Bio-Sci. 30(2): 13-22, 2022

Facilitating direct interspecies electron transfer in anaerobic digestion via speeding up transmembrane transport of electrons and CO2 reduction in methanogens by Na+ adjustment

The possibility of facilitating direct interspecies electron transfer (DIET) in anaerobic digestion with different concentrations of NaCl was explored. Additional NaCl at 2 or 4 g/L strengthened anaerobic digestion to resist the high-organic loading rate impacts, whereas the higher concentrations of NaCl (6 or 8 g/L) suppressed methanogenesis. Additional MgCl2 with the same ion strength as NaCl at 2 g/L had no effect on performances. Additional NaCl at 2 or 4 g/L dramatically increased the abundance of Methanosarcina species (20.7%/23.4% vs 8.6%) and stimulated the growth of Sphaerochaeta and Petrimonas species that could transfer electrons to the soluble Fe(III) or elemental sulfur. Electrochemical evidences showed that, additional NaCl at 2 or 4 g/L increased capacitances and decreased charge transfer resistances of Methanosarcina-dominant communities. Metagenomic evidences showed that, additional NaCl at 2 or 4 g/L increased the abundance of genes that encoded the type IV pilus assembly proteins (1.98E-04/1.87E-04 vs 1.85E-04) and cytochrome c-like proteins (5.51E-04/5.60E-04 vs 5.31E-04). In addition, additional NaCl at 2 or 4 g/L increased the abundance of genes for methanophenazine (MP)/MPH2 transformation (1.04E-05/1.24E-05 vs 8.06E-06) and CO2 reduction (1.64E-03/1.86E-03 vs 1.06E-03), suggesting a rapid transmembrane transport of electrons and CO2 reduction in methanogens. Both processes were closely associated with F420/F420H2 transformation that required ATP. Additional NaCl at 2 or 4 g/L increased the yield of ATP (256.0/249.3 vs 231.8 nmol/L) that might promote F420/F420H2 transformation in methanogens, which overcame the thermodynamic limitations of combining electrons with protons for the reduction of CO2 to methane and facilitated DIET.

Solution-cathode glow discharge under high NaCl concentration: Impact on excitation conditions and analyte transfer processes

The Solution-Cathode Glow Discharge (SCGD) is a useful plasma source for elemental analysis, gathering atomization/excitation/ionization capabilities for aqueous solutions with simplicity and low consumption. When combined with Optical Emission Spectrometry (OES), ng/mL limits of detection can be achieved for multiple elements. Additionally, this plasma source presents certain robustness against the presence of dissolved non-analyte ions. Nevertheless, the mechanisms by which the SCGD can transfer the dissolved analytes from the solution into the plasma, and the mechanisms of how concomitant ions in the sample solution affect the performance of the analysis, are still not fully understood. Therefore, fundamental plasma diagnostics of the SCGD are performed in this work, including electrical measurements, electron densities and rotational and excitation temperatures. In particular, these measurements are performed introducing solutions with NaCl concentrations up to 3.5 g/L in order to understand how they affect the atomization/excitation efficiency and the analyte solution-to-plasma transfer processes of the source. The information is correlated with the signal produced by three analytes (Cd, Zn and Cu).

High NaCl concentrations induce the resistance to thermal denaturation of an extremely halotolerant (salt-activated) β-mannanase from Bacillus velezensis H1.

β-mannanase catalyzes the hydrolysis of mannans β-1,4-mannosidic linkages to produce industrially relevant oligosaccharides. These enzymes have numerous important applications in the detergent, food, and feed industries, particularly those that are resistant to harsh environmental conditions such as salts and heat. While, moderately salt-tolerant β-mannanases are already reported, existence of a high halotolerant β-mannanase is still elusive. This study aims to report the first purification and characterization of ManH1, an extremely halotolerant β-mannanase from the halotolerant B. velezensis strain H1. Electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) analysis revealed a single major peak with a molecular mass of 37.8kDa demonstrating its purity. The purified enzyme showed a good thermostability as no activity was lost after a 48h incubation under optimal conditions of 50°C and pH 5.5. The enzyme's salt activation nature was revealed when its maximum activity was obtained in the presence of 4M NaCl,it doubled compared to the no-salt condition. Moreover, NaCl strengthens its resistance to thermal denaturation, as its melting temperature (Tm) increased steadily with increasing NaCl concentrations reaching 75.5°C in the presence of 2.5M NaCl. The Km and Vmax values were 5.63mg/mL and 333.33 µmol/min/mL, respectively, using carob galactomannan (CG) as a substrate. The enzyme showed a significant ability to produce manno-oligosaccharides (MOS) from lignocellulosic biomass releasing 13mg/mL of reducing sugars from olive mill wastes (OMW)after 24h incubation. The results revealed that this enzyme may have significant commercial values for agro-waste treatment, and other potential applications.

Quasi-In Situ Localized Corrosion of an Additively Manufactured FeCo Alloy in 5 Wt Pct NaCl Solution

FeCo alloys are important materials used in pumps and motors in the offshore oil and gas drilling industry. These alloys are subjected to marine environments with a high NaCl concentration, therefore, corrosion and catastrophic failure are anticipated. So, the surface dissolution of additively manufactured FeCo samples is investigated in a quasi-in situ manner, in particular, the pitting corrosion in 5.0 wt pct NaCl solution. The local dissolution of the same sample region is monitored after 24, 72, and 168 hours. Here, the formation of rectangular and circular pits of ultra-fine dimensions (less than 0.5 µm) is observed with increasing immersion time. In addition, the formation of a corrosion-inhibiting surface layer is detected on the sample surface. Surface dissolution leads to a change in the surface structure, however, no change in grain shape or grain size is noticed. The surface topography after local dissolution is correlated to the grain orientation. Quasi-in situ analysis shows the preferential dissolution of high-angle grain boundaries (HAGBs) leading to a change in the fraction of HAGBs and low-angle grain boundaries fraction (LAGBs). For the FeCo sample, a potentiodynamic polarisation test reveals a corrosion potential (Ecorr) of − 0.475 V referred to the standard hydrogen electrode (SHE) and a corrosion exchange current density (icorr) of 0.0848 A/m2. Furthermore, quasi-in situ experiments showed that grains oriented along certain crystallographic directions are corroding more compared to other grains leading to a significant decrease in the local surface height. Grains with a plane normal close to the langle {1}00rangle direction reveal lower surface dissolution and higher corrosion resistance, whereas planes normal close to the langle {11}0rangle direction and the langle {111}rangle direction exhibit a higher surface dissolution.

Effect of induction mode on 3D printing characteristics of whey protein isolate emulsion gel

This study mainly explored the influence of different induction modes such as NaCl and Transglutaminase on the 3D printing characteristics of whey protein isolate emulsion gel. The properties of gel were characterized from rheological properties, microstructure, Fourier transform infrared spectroscopy, thermal stability and other aspects, and the relationship between 3D printing molding characteristics of gel and its applicability as a diet for dysphagia was discussed. Strain and frequency sweep showed that the addition of NaCl made gel difficult to be extruded during printing, while the addition of TG could get the opposite result. From a microscopic point of view, too high concentration of NaCl would lead to the disordered aggregation of proteins, which would reduce the structural strength of gel and make the water binding unstable. The addition of TG made the gel network have an orderly three-dimensional structure, making the water binding more stable. Both NaCl and TG can cause the secondary structure of protein to be more orderly and the thermal stability to be reduced, and the texture characteristics such as hardness, resilence, springiness, gumminess and chewiness to be reduced. During 3D printing of emulsion gel containing high concentration of NaCl, unsmooth extrusion filaments and pattern collapse occurred. TG can significantly improve the accuracy of 3D printing products. This study provided a basis for the application of whey protein isolate emulsion gel in 3D printing.