Halophiles

Halophiles are extremophilic salt-loving microorganisms that can survive in an extremely high level of salinity (10-30% NaCl). They belong to all three groups (i.e., bacteria, archaea, and eukaryotes). Halophiles tolerate high salt concentration due to unique cellular adaptations like salt-in strategy, compatible solute strategy, and enzyme adaptations. The chapter describes the classification, physiology, ecology, and mechanisms of adaptations and biotechnological applications of halophiles.

High salt diet impairs dermal tissue remodeling in a mouse model of IMQ induced dermatitis

Recent animal studies, as well as quantitative sodium MRI observations on humans demonstrated that remarkable amounts of sodium can be stored in the skin. It is also known that excess sodium in the tissues leads to inflammation in various organs, but its role in dermal pathophysiology has not been elucidated. Therefore, our aim was to study the effect of dietary salt loading on inflammatory process and related extracellular matrix (ECM) remodeling in the skin. To investigate the effect of high salt consumption on inflammation and ECM production in the skin mice were kept on normal (NSD) or high salt (HSD) diet and then dermatitis was induced with imiquimod (IMQ) treatment. The effect of high salt concentration on dermal fibroblasts (DF) and peripheral blood mononuclear cells (PBMC) was also investigated in vitro. The HSD resulted in increased sodium content in the skin of mice. Inflammatory cytokine Il17 expression was elevated in the skin of HSD mice. Expression of anti-inflammatory Il10 and Il13 decreased in the skin of HSD or HSD IMQ mice. The fibroblast marker Acta2 and ECM component Fn and Col1a1 decreased in HSD IMQ mice. Expression of ECM remodeling related Pdgfb and activation phosphorylated (p)-SMAD2/3 was lower in HSD IMQ mice. In PBMCs, production of IL10, IL13 and PDGFB was reduced due to high salt loading. In cultured DFs high salt concentration resulted in decreased cell motility and ECM production, as well. Our results demonstrate that high dietary salt intake is associated with increased dermal pro-inflammatory status. Interestingly, although inflammation induces the synthesis of ECM in most organs, the expression of ECM decreased in the inflamed skin of mice on high salt diet. Our data suggest that salt intake may alter the process of skin remodeling.

GENETIC MODIFICATION FOR SALT AND DROUGHT TOLERANCE IN PLANTS THROUGH SODERF3

Plants constitute the major part of the ecosystem and maintain balance through their different roles in the stability of the environment. As plants have an impact over environment; in the same manner environment interacts with plants. These interactions bring some productive results or sometimes may cause serious issues to plants. The environment poses some serious threats to plants as it is changing drastically over the course of years. Plants have been resistant to many of biotic and abiotic stresses naturally but now it is getting challenging. The major issues faced by plants are drought, high salt concentration, temperature and many other factors. These issues can be compensated by engineering plants with such novel genes which cause the release of ethylene responsive factor in the case of drought and salt intolerance. There are various studies to engineer the stress sensitive plants with SodERF3, a novel sugarcane ethylene responsive factor which causes promising tolerance in transgenic plants.

Sugarcane Plant Growth and Physiological Responses to Soil Salinity during Tillering and Stalk Elongation

A pot study was conducted to investigate influences of salinity on sugarcane (Saccharum spp.) plant growth, leaf photosynthesis, and other physiological traits during tillering and stalk elongation. Treatments included two commercial sugarcane cultivars (Canal Point (CP) 96-1252 and CP 00-1101) and an Erianthus with five different soil salt concentrations (0 [Control], 38, 75, 150, and 300 mM of NaCl added). Growth (tillers, plant height, and nodes) and physiological (leaf net photosynthetic rate [Pn], stomatal conductance [gs], intercellular CO2 concentration, and leaf water soluble sugar concentrations) characters were determined during the experiment. Responses of sugarcane growth, photosynthesis, and photoassimilate translocation to salinity depended on soil salt concentration. Plant height was the most sensitive while the number of nodes was the most tolerant to soil salinity among the three growth traits measured. CP 96-1252 differed from CP 00-1101 significantly in response of shoot:root ratio to high salt concentration. Leaf Pn of plants treated with the 38 mM salt did not differ from that of the control plant, but plants treated with the 75, 150, and 300 mM salt had 12.7, 18.7, and 35.3% lower leaf Pn, respectively, than the control. The low leaf Pn due to salinity was associated with not only the decrease in gs, but also the non-stomatal factors. Results of leaf sugar composition and concentrations revealed that high salt concentration also depressed photoassimilate translocation from leaves to other plant tissues. These findings are important for better understanding of some physiological mechanisms of salinity influence on sugarcane growth and yields.

Drawbacks of Low Lattice Energy Ammonium Salts for Ion-Conducting Polymer Electrolyte Preparation: Structural, Morphological and Electrical Characteristics of CS:PEO:NH4BF4-Based Polymer Blend Electrolytes

In the present work it was shown that low lattice energy ammonium salts are not favorable for polymer electrolyte preparation for electrochemical device applications. Polymer blend electrolytes based on chitosan:poly(ethylene oxide) (CS:PEO) incorporated with various amounts of low lattice energy NH4BF4ammonium salt have been prepared using the solution cast technique. Both structural and morphological studies were carried out to understand the phenomenon of ion association. Sharp peaks appeared in X-ray diffraction (XRD) spectra of the samples with high salt concentration. The degree of crystallinity increased from 8.52 to 65.84 as the salt concentration increased up to 40 wt.%. These are correlated to the leakage of the associated anions and cations of the salt to the surface of the polymer. The structural behaviors were further confirmed by morphological study. The morphological results revealed the large-sized protruded salts at high salt concentration. Based on lattice energy of salts, the phenomena of salt leakage were interpreted. Ammonium salts with lattice energy lower than 600 kJ/mol are not preferred for polymer electrolyte preparation due to the significant tendency of ion association among cations and anions. Electrical impedance spectroscopy was used to estimate the conductivity of the samples. It was found that the bulk resistance increased from 1.1 × 104 ohm to 0.7 × 105 ohm when the salt concentration raised from 20 wt.% to 40 wt.%, respectively; due to the association of cations and anions. The low value of direct current (DC) conductivity (7.93 × 10−7 S/cm) addressed the non-suitability of the electrolytes for electrochemical device applications. The calculated values of the capacitance over the interfaces of electrodes-electrolytes (C2) were found to drop from 1.32 × 10−6 F to 3.13 × 10−7 F with increasing salt concentration. The large values of dielectric constant at low frequencies are correlated to the electrode polarization phenomena while their decrements with rising frequency are attributed to the lag of ion polarization in respect of the fast orientation of the applied alternating current (AC) field. The imaginary part of the electric modulus shows obvious peaks known as conduction relaxation peaks.