Relative Content Research Articles

Overexpression of Auxin/Indole-3-Acetic Acid Gene TrIAA27 Enhances Biomass, Drought, and Salt Tolerance in Arabidopsis thaliana

White clover (Trifolium repens L.) is an important forage and aesthetic plant species, but it is susceptible to drought and heat stress. The phytohormone auxin regulates several aspects of plant development and alleviates the effects of drought stress in plants, including white clover, by involving auxin/indole acetic acid (Aux/IAA) family genes. However, Aux/IAA genes and the underlying mechanism of auxin-mediated drought response remain elusive in white clover. To extend our understanding of the multiple functions of Aux/IAAs, the current study described the characterization of a member of the Aux/IAA family TrIAA27 of white clover. TrIAA27 protein had conserved the Aux/IAA family domain and shared high sequence similarity with the IAA27 gene of a closely related species and Arabidopsis. Expression of TrIAA27 was upregulated in response to heavy metal, drought, salt, NO, Ca2+, H2O2, Spm, ABA, and IAA treatments, while downregulated under cold stress in the roots and leaves of white clover. TrIAA27 protein was localized in the nucleus. Constitutive overexpression of TrIAA27 in Arabidopsis thaliana led to enhanced hypocotyl length, root length, plant height, leaf length and width, and fresh and dry weights under optimal and stress conditions. There was Improved photosynthesis activity, chlorophyll content, survival rate, relative water content, endogenous catalase (CAT), and peroxidase (POD) concentration with a significantly lower electrolyte leakage percentage, malondialdehyde (MDA) content, and hydrogen peroxide (H2O2) concentration in overexpression lines compared to wild-type Arabidopsis under drought and salt stress conditions. Exposure to stress conditions resulted in relatively weaker roots and above-ground plant growth inhibition, enhanced endogenous levels of major antioxidant enzymes, which correlated well with lower lipid peroxidation, lower levels of reactive oxygen species, and reduced cell death in overexpression lines. The data of the current study demonstrated that TrIAA27 is involved in positively regulating plant growth and development and could be considered a potential target gene for further use, including the breeding of white clover for higher biomass with improved root architecture and tolerance to abiotic stress.

Transcriptome Profiling Identifies Plant Hormone Signaling Pathway-Related Genes and Transcription Factors in the Drought and Re-Watering Response of Ginkgo biloba

Ginkgo biloba, usually referred to as a “living fossil,” is widely planted in many countries because of its medicinal value and beautiful appearance. Owing to ginkgo’s high resistance to drought stress, ginkgo seedlings can even survive withholding water for several days without exhibiting leaf wilting and desiccation. To assess the physiological and transcriptomic mechanisms involved in the drought stress and re-watering responses of Ginkgo biloba, ginkgo seedlings were subjected to drought treatment for 15 d (D_15 d) and 22 d (D_22 d) until they had severely wilted, followed by re-watering for 3 d (D_Re3 d) to restore normal growth. Variations in physiological characteristics (relative water content, malondialdehyde (MDA) content, stomatal aperture, and antioxidant enzyme activity) during drought and re-watering were assessed. In total, 1692, 2031, and 1038 differentially expressed genes (DEGs) were upregulated, while 1691, 2820, and 1910 were downregulated in D_15 d, D_22 d, and D_Re3 d, respectively, relative to the control. Three pathways, namely, plant hormone signal transduction, plant–pathogen interaction, and the plant MAPK signaling pathway, were enriched during drought stress and re-watering. The DEGs involved in plant hormone signal transduction pathways (those of IAA, CTK, GA, ABA, ETH, BR, SA, and JA) and the major differentially expressed transcription factors (TFs; MYB, bHLH, AP2/ERF, NAC, WRKY, and bZIP) were identified. Quantitative real-time PCR revealed six TFs as positive or negative regulators of drought stress response. These phenotype-related physiological characteristics, DEGs, pathways, and TFs provide valuable insights into the drought stress and re-watering responses in G. biloba.

Variability of superoxide dismutase isoenzymes in varieties and introgressive lines of wheat differing in drought resistance

Aim. To study the variability of the component composition of superoxide dismutase (SOD) isoenzymes under the influence of hyperthermia and water deficit in introgressive lines of wheat with different drought resistance. Methods. The activity of SOD isoforms was determined using native electrophoresis in an acidic medium in a polyacrylamide gel. Results. Under the impact of stress factors (elevated temperature, water deficit and their combined effects), a redistribution of the relative content of individual SOD isoforms was observed in wheat seedlings of drought-resistant and drought-susceptible genotypes compared to growing under favorable conditions. The most significant decrease occurred due to the joint action of water deficit and increased temperature. Under these conditions, enzyme isoforms of medium electrophoretic mobility practically disappeared. Conclusions. The presence of low-mobility isoforms of SOD in wheat seedlings under the impact of stress factors (elevated temperature and water deficit) can serve as an indicator of drought resistance of wheat plants.

Experimental model of systemic inflammation during acetaminophen toxicity

Acetaminophen is one of the most toxic drugs that can cause liver damage. At the same time, acetaminophen-induced liver failure is closely associated with the development of systemic inflammatory response syndrome. However, there is no drug aimed at suppressing the systemic inflammatory response. That is, this issue needs to be studied experimentally, but a model of systemic inflammation during acetaminophen overdose has not yet been obtained. Therefore, it was decided to develop an experimental model of systemic inflammation during acetaminophen overdose. The purpose of this study was to experimentally substantiate the semi-lethal dose for acetaminophen overdose in C57Bl/6 mice and to evaluate the readings of blood tests after administration of the drug. To determine the semi-lethal dose, male C57Bl/6 mice were intraperitoneally injected with “Ifimol” (Unique Pharmaceutical Laboratories, India) or acetaminophen solution (Sigma-Aldrich, USA) with a concentration of 14 mg/ml in different doses. When introducing “Ifimol”, it was not possible to achieve a semi-lethal dose. When administering a solution of acetaminophen, 50% mortality was recorded at a dose of 600 mg/kg body weight. After establishing a semi-lethal dose, the experimental group was administered an acetaminophen solution (Sigma-Aldrich, USA) with a concentration of 14 mg/ml at a dose of 600 mg/kg. The control group was injected with saline in an equivalent volume. On the second day, liver and peripheral blood samples were taken. Subsequently, hematological and biochemical blood tests and histological analysis were performed. Histological examination revealed centrilobular necrosis and disorganization of the liver structure. According to the biochemical blood test, the activity of aspartate aminotransferase, alanine aminotransferase, creatinine concentration, and the de Ritis coefficient differed statistically significantly (p 0.05) in the experimental group compared to the control group. Among the hematological blood test parameters, there were statistically significant differences in the number of leukocytes, platelets, as well as the absolute and relative content of granulocytes and lymphocytes. Thus, 48 hours after administration of a semi-lethal dose of acetaminophen, there were signs of damage to internal organs (liver, kidneys) and changes in immune system parameters, which are similar to components of systemic inflammation in humans.

Morpho-physiological and biochemical responses of radish (Raphanus sativus L.) under cadmium stress

The accumulation of cadmium (Cd) in plants poses a major risk to consumer health, in addition to affecting plant growth, development and quality. The study aimed to examine the effects of cadmium on the plants' ability for photosynthesis and antioxidant enzyme activity. In this study, radishes were planted in Petri dishes and pots containing soil supplemented with different concentrations of cadmium sulphate (25, 50, and 100 mg Cd kg-1 soil). The results showed that the percentage of germination, seedlings length, and fresh and dry matter significantly declined its increasing cadmium concentrations. In addition, cadmium hindered plant growth, as evidenced by the fresh and dried weight of radish roots and leaves after a 100 mg Cd kg-1 soil treatment. There was also a notable decrease in chlorophyll a and chlorophyll b, total chlorophyll, and total leaf area per plant. The leaves of radish plant exhibited a significant increase in lipid peroxidation and electrolyte leakage contents under Cd stress, while, the relative water content (RWC) decreased. However, leaves and roots of radish plant showed a considerable increase in antioxidant enzymes (catalase; CAT, peroxidase; POD, and superoxide dismutase; SOD). Furthermore, radish showed a significant increase in Cd accumulation in all applications, however, there were no obvious symptoms of Cd toxicity following the 25 and 50 mg Cd kg-1 soil applications. In conclusion, the radish plants accumulated cadmium at higher concentrations (100 mg Cd kg-1 soil). So, we recommended cultivating the radish plants in soil that has low concentrations of cadmium.

Foliar application of rice husk derived nanosilica for mitigating drought stress in hybrid maize by boosting antioxidant defense system

The increasing frequency and intensity of drought magnified by the climate change, pose significant challenge to global food security and agricultural productivity. Chemically synthesized nanosilica have emerged as a promising solution for managing drought stress, enhancing crop growth and stress resilience but, its production involves harmful chemicals which results in adverse impacts on soil, plant and environment. Hence, the present study aimed to green synthesize and characterize silicon nanoparticles from rice husk and to evaluate their potential for improving plant growth, development and stress mitigation in hybrid maize. The rice husk derived nanosilica has spherical morphology, amorphous nature, siloxane bonds and high purity (99 %). Five different levels of nanosilica (0.05, 0.10, 0.15, 0.20 and 0.25 %) were sprayed on hybrid maize grown under irrigated and drought conditions and the results revealed that, nanosilica spray has improved the stress tolerance, growth and photosynthetic parameters. An optimum response was noted with the nanosilica spray upto 0.10 % in irrigated plants and 0.15 % in drought stressed plants, where greater increase in plant height (27.7 and 28.9 %), total biomass (55.7 and 39.1 %), chlorophyll a (36.7 and 54.5 %), relative water content (12.5 and 24.9 %) and superoxide dismutase (23.0 and 35.7 %) activity was observed. This was ascribed to the alleviation of membrane damage by reduced melondialdehyde content (18.9 and 21.4 %) and electrolyte leakage (21.9 and 26.7 %) under irrigated and drought regimes. However, higher doses of nanosilica caused slight reduction in plant growth and antioxidant activity. We conclude that, foliar spraying of nanosilica synthesized from rice husk at a concentration of 0.10 % for irrigated and 0.15 % for hybrid maize exposed to drought stress has shown a positive effect on plant growth and stress mitigation. Nanosilica synthesised from rice husk is economical, environmentally feasible and efficiently boosts plant growth and stress tolerance. Further, to confirm the role of rice husk derived nanosilica in plant stress tolerance, the comprehensive molecular mechanisms underpinning the stress mitigation has to be studied in detail.

Modulating reactive oxygen species and ion homeostasis for combined salt and cadmium stress tolerance in Brassica campestris: The role of beneficial microbes

The land areas and crop species adversely impacted by salinity and heavy metals are growing rapidly. Current research indicates that plant growth-promoting microorganisms offer an environmentally friendly option for improving physiological and biochemical processes in plants growing under stress conditions. The aim of the present study was to investigate the potential mitigation of simultaneous salinity and cadmium (Cd) stress in rapeseed (Brassica campestris cv. BARI Sarisha-17) by the application of Azospirillum sp. (Az), phosphate solubilizing bacteria (PSB), potassium mobilizing bacteria (KMB), and vesicular arbuscular mycorrhiza (VAM). Seeds were treated with PSB or KMB prior to sowing, whereas Az, PSB, KMB, or VAM were added as supplements during soil preparation. At 21 days after sowing, the plants were treated with a combination of salt (100 mM NaCl) and Cd (0.25 mM CdCl2), with several applications at 7-day intervals. The combination of salt and Cd stress decreased plant growth and biomass, relative water content, and photosynthetic pigment levels, while also increased electrolyte leakage, lipid peroxidation, and the generation of excess reactive oxygen species (ROS). Salt and Cd stress also impaired plant ion balances of sodium, potassium and nitrate, antioxidant defenses, and glyoxalase system activity. Application of Az, PSB, or KMB restored these parameters to unstressed levels by facilitating the scavenging of ROS, maintaining water status, restoring ion balances, enhancing plant antioxidant defenses, and increasing glyoxalase enzyme activity, while reducing methylglyoxal toxicity and improving photosynthetic activity. The application of KMB was the most effective; however, all microbe supplementations showed the ability to alleviate the damage caused by stress in rapeseed. These findings highlight the ability of soil microorganisms with plant growth-promoting properties to improve the physiological and biochemical functions of rapeseed under Cd and salt stress.

Enhancing growth and tolerance traits in pepper (Capsicum annuum L.) through water-saving irrigation practices

Due to their intensive cultivation, horticultural crops are particularly susceptible and vulnerable to the detrimental effects of drought stress, necessitating significant water inputs for optimal growth and yield. Accordingly, water-saving irrigation strategies, i.e., Partial Root zone Drying (PRD) and Regulated Deficit Irrigation (RDI) emerge as pivotal tools for bolstering the resilience of the horticultural sector. The current study aims to evaluate the impact of PRD and RDI strategies on pepper (Capsicum annuum L.) growth, and physio-biochemical attributes under semi-controlled greenhouse conditions. Research findings revealed pronounced enhancements in stem length under both irrigation strategies, with PRD exhibiting superior effects on shoot fresh and dry biomass (increases of 57.2% and 61.1%, respectively) compared to full irrigation. At the physiological level, PRD and RDI induced a significant reduction in stomatal conductance in pepper plants relative to full irrigation, while maintaining leaf water potential and relative water content. Biochemically, plants subjected to PRD and RDI methods exhibited significant accumulation of free proline, particularly pronounced with PRD (approximately 115.9% increase compared to full irrigation). Furthermore, Chl a and carotenoid concentration significantly increased under PRD, indicating sustained photosynthetic functionality. Comparatively, PRD appears as the more effective technique, offering the potential to conserve agricultural water about 50 without compromising growth parameters, while simultaneously enhancing tolerance traits in C. annuum. Nonetheless, further investigations on other traits across diverse soil types, climates, and cultivars under field conditions are imperative to ascertain the broader applicability of PRD and optimize its implementation.

Biocontrol of Fusarium oxysporum-infested Gastrodia elata Bl. by Lactobacillus curvatus 2768-VOCs and mechanism of inhibition

Gastrodia elata Bl. Is susceptible to infestation by the fungus Fusarium oxysporum, which can cause severe post-harvest diseases. This paper presents the findings of an investigation into the control and bacteriostatic mechanisms of Lactobacillus curvatus 2768-VOCs on F. oxysporum-infected G. elata. The results of both in vitro and in vivo tests demonstrated that L. curvatus 2768-VOCs exhibited inhibitory effects against F. oxysporum, with inhibition rates of 63.37% and 44.4%, respectively. The results of the in vivo test also demonstrated that the pre-fumigation approach exhibited superior efficacy compared to direct fumigation, with the former showing a preventive effect. Furthermore, it was discovered that VOCs disrupted the integrity of F. oxysporum cell membranes and altered their permeability, resulting in the leakage of cell contents. The fumigation caused damage to the mycelial structure, accompanied by a notable decline in the total lipid and ergosterol content, and an appreciable increase in MDA content. Moreover, the fumigation of VOCs markedly diminished the activities of ATPase and mitochondrial dehydrogenase, thereby disrupting the respiration of F. oxysporum and its energy metabolism. The VOCs were subjected to GC-MS analysis, which revealed that the relative content of acids was the highest, particularly formic acid and glyoxalic acid. The study offers a theoretical basis for the biological control of postharvest diseases in G. elata.

Monitoring the temporal variations of plant stress using the air pollution tolerance index in the Sejzi industrial area (Isfahan, Iran).

The objective of this study was to screen air pollution-induced stress in some plant species in the Sejzi industrial region (Isfahan, Iran). An assessment of APTI and other physiological and biochemical features of significant species in the area was conducted across three seasons: spring, summer, and autumn. The physiological and biochemical factors of the following species were evaluated: Limonium persicum, Atriplex lentiformis, Nitraria schoberi, Haloxylon persicum, Tamarix hispida, Zygophyllum atriplicoides, Karelinia caspica, and Prosopis farcta. The physiological factors assessed included acidity and relative humidity content, while the biochemical factors assessed included proline, sugar, ascorbic acid, and total chlorophyll. Subsequently, a thorough evaluation was carried out on the species under investigation to ascertain their biomonitors' capabilities and APTI. The study findings indicated that the species P. farcta, N. schoberi, and K. caspica consistently had high APTI values during the spring, autumn, and summer seasons, classifying them as tolerant plant species. Conversely, the observed traits showed significant fluctuations across the seasons. The investigation's findings indicate that the species L. persicum, N. schoberi, and K. caspica exhibit higher annual averages of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid compared to other species. The examination of the annual variation in the tolerance levels of plant species to pollution ranked from highest to lowest was as follows: N. schoberi, P. farcta, K. caspica, Z. atriplicoides, H. persicum, T. hispida, L. persicum, and A. lentiformis. Moreover, based on the annual average, the primary determinants that impact the APTI in the species being studied include ascorbic acid (35%), leaf acidity (19%), total chlorophyll content (35%), and relative humidity content (69%). Furthermore, a distinct and significant correlation was found between proline and sugar levels and the annual APTI values. Additionally, the species P. farcta had the highest API compared to other species. The study revealed the high potential of some plant species against air pollution induced stress which can be used in air and dust pollution management in the region.

Suppression of SlHDT1 expression increases fruit yield and decreases drought and salt tolerance in tomato.

Histone deacetylation, one of most important types of post-translational modification, plays multiple indispensable roles in plant growth and development and abiotic stress responses. However, little information about the roles of histone deacetylase in regulating inflorescence architecture, fruit yield, and stress responses is available in tomato. Functional characterization revealed that SlHDT1 participated in the control of inflorescence architecture and fruit yield by regulating auxin signalling, and influenced tolerance to drought andsalt stresses by governing abscisic acid (ABA) signalling. More inflorescence branches and higher fruit yield, which were influenced by auxin signalling, were observed in SlHDT1-RNAi transgenic plants. Moreover, tolerance to drought andsalt stresses was decreased in SlHDT1-RNAi transgenic lines compared with the wild type (WT). Changes in parameters related to the stress response, including decreases in survival rate, chlorophyll content, relative water content (RWC), proline content, catalase (CAT) activity and ABA content and an increase in malonaldehyde (MDA) content, were observed in SlHDT1-RNAi transgenic lines. In addition, the RNA-seq analysis revealed varying degrees of downregulation for genes such as the stress-related genes SlABCC10 and SlGAME6 and the pathogenesis-related protein P450 gene SlCYP71A1, and upregulation of the pathogenesis-related protein P450 genes SlCYP94B1, SlCYP734A7 and SlCYP94A2 in SlHDT1-RNAi transgenic plants, indicating that SlHDT1 plays an important role in the response to biotic and abiotic stresses by mediating stress-related gene expression. In summary, the data suggest that SlHDT1 plays essential roles in the regulation of inflorescence architecture and fruit yield and in the response to drought andsalt stresses.

Genetic stability evaluation of caladium somaclonal variants by morphological, cytological, and SSR analysis in three successive generations

Somaclonal variants with valuable agronomic traits play a crucial role in crop breeding, provided that they are stably passed down in subsequent generations. Although numerous somaclonal variants have been identified and studied among in vitro regenerated plants in the foliage plant caladium (Caladium × hortulanum Birdsey), no research has been carried out to evaluate their genetic stability in subsequent generations. This study aimed to evaluate the genetic stability of three types of diploid caladium somaclonal variants, previously derived from in vitro callus cultures, over three successive tuber-propagated generations. The analysis of quantitative morphological characteristics revealed a greater degree of variation among the established plants in the first generation (G1) compared to the second (G2) and third generations (G3). Seven plants exhibiting distinct leaf coloration changes were identified in the G1 generation and were found to be stably passed down to the subsequent G2 and G3 generations. These findings indicate a wide range of morphological variation in the G1 generation, followed by relative stability in subsequent generations. A comprehensive cytological and molecular analysis revealed that five of the seven newly observed variants displayed notable differences in relative nuclear DNA content, chromosome number, or SSR (simple sequence repeat) banding patterns compared to their corresponding normal counterparts. The findings of this study will be instrumental in developing new cultivars with distinctive plant morphology through the exploitation of somaclonal variation in caladium.

Significance of relative and absolute content of blood lymphocyte subopopulations for differential diagnosis of viral and bacterial meningitis in children

The search for markers of early etiological verification of meningitis is an urgent task for clinical laboratory diagnostics.Objective of the study is to determine the significance of relative and absolute content of blood lymphocyte subpopulations for early differential diagnosis of viral and bacterial meningitis in children.Materials and methods. There was performed a clinical and laboratory examination of 61 children, 37 of them were diagnosed with viral meningitis, and 24 ones – with bacterial purulent meningitis. The control group included 15 healthy children. The relative and absolute content of the main subpopulations (T-lymphocytes: T-helpers (Th), cytotoxic T-lymphocytes (CTL), NK, B-cells) and small subpopulations (NKT, DNT- and DPT-lymphocytes, CD3+CD8br, CD3+CD8dim, CD3-CD8+NK) of lymphocytes was assessed by flow cytometry. Statistical analysis of the data was carried out.Results. The decrease of relative and absolute content of all studied subpopulations was identified during an acute period of bacterial purulent meningitis, in comparison with the control group, with the exception of B-lymphocytes, the number of them was increased. Absolute content of all subpopulations was reduced in case of viral meningitis compared with the control group, the relative content did not have any significant differences, with the exception of an increase in the relative content of B-lymphocytes. Calculation of diagnostic sensitivity and specificity revealed the effectiveness of identification of both relative and absolute content of lymphocyte subpopulations for differential diagnosis of viral or bacterial meningitis. Identification of B-lymphocytes, NKT, CD3+CD8dim in the blood had the highest diagnostic efficiency (area under the ROC curve (AUC) ranging from 0,9 to 1).Conclusion. Assessment of relative and absolute content of blood lymphocyte subpopulations is an effective tool for laboratory differential diagnosis of viral and bacterial meningitis and can be used as an early differential diagnostic criterion, especially in case of impossibility to analyze the composition of cerebrospinal fluid.

Comparative Analyses of Muscle Quality in Hooked, Trawl-Net, and Radar-Net Hairtail (Trichiurus haumela) during Thermal Processing.

To investigate and compare the changes in muscle quality of hooked, trawl-net, and radar-net hairtail (Trichiurus haumela, HH, TH, and RH) during thermal processing, the physicochemical properties of three kinds of hairtail were determined under heating at 30, 50, 70 and 90 °C for 10 min. Additionally, the muscle tissues were observed via Oil Red O (ORO) staining, Masson staining, and scanning electron microscopy (SEM). The results showed that with increased heating temperature, pH, L*, b*, chewiness, and gumminess in hairtail muscle increased, while a* and shearing force decreased. The springiness, relative contents of hydrophobic and disulfide bonds, myosin surface hydrophobicity, and TCA-soluble peptide content increased first and then decreased. However, the relative contents of ionic and hydrogen bonds showed an opposite trend. Histological observations revealed that heating disrupted hairtail muscle tissue, manifested by the blurriness and disorder of myofibrils and breakage of myofibrillar bundle membranes. The RH muscle exhibited the highest chewiness, gumminess, and chemical force levels, accompanied by the lowest content of TCA-soluble peptide. Furthermore, the RH muscle presented the greatest fat droplet content, diffusivity, and integrity of collagen and myofibers. Correlation analysis revealed a close correlation between muscle quality and protein function in HH, TH, and RH. This study provides a theoretical basis for the difference in muscle quality in three different types of hairtail.

Adsorption Behavior of Different Components of a Polymer/Surfactant Composite Control System along an Injection-Production Channel in Sand Conglomerate Reservoirs.

Sandy conglomerate reservoirs have become an important replacement area for unconventional energy to increase reserves and production. The polymer/surfactant composite control flooding system can effectively alleviate the water flooding front breakthrough caused by the interlayer or plane heterogeneity of the sand conglomerate reservoir and is an effective production method to reduce the water cutoff of the well and increase the oil recovery. In the process of controlling the oil displacement process of the system, the chromatographic separation effect was found due to the different viscosities of each component and the adsorption difference between the components and the rock, which weakened the development effect of the reservoir. It is necessary to study the adsorption law of each component of the complex controlled displacement system along the injection-production channel in the sand conglomerate reservoir. In this study, the microstructure and mineral composition of sandy conglomerates were determined by scanning electron microscopy and X-ray diffraction tests. The main particle size distribution was counted through a rock particle sieving experiment. A new characterization method called the large-size core physical model was used. The composite control system of sulfonate and betaine was used as the surfactant component, and the adsorption degree of each component in the displacement process was analyzed. The experimental results showed that the mass fraction of the sandy conglomerate increased with the decrease in particle size. The particles with a size of less than 0.08 mm account for a relatively high proportion, with a mass fraction of 60%. The content of brittle minerals, such as quartz and feldspar, in the glutenite was relatively high, and micrometer-sized pores and fractures were developed. The main factors affecting the viscosity of the composite system were the concentration and molecular weight of the polymer. The increase of injection volume of the flooding system is conducive to the maintenance of ultralow interfacial tension migration to the deep core. In the displacement process, when the polymer molecular chain was cut to a certain extent, the effect of throat shear was also slowed due to the short molecular chain. However, the shortened polymer molecules were more easily adsorbed on the surface of rock particles and the adsorption rate increased. The adsorption capacity of each component gradually decreased with the increase of the injection volume and injection concentration. The relative content of the composite control system and crude oil affects the type of emulsion, which undergoes a corresponding transformation during the driving process from a water-in-oil emulsion to an oil-in-water one. The research results of this paper enrich the mechanism of enhancing oil recovery of sand conglomerate reservoirs by polymer-surfactant composite regulation technology.

Impact of Neurotransmitters on the Fatty Acid Composition and the Pigments of the Green Microalga Scenedesmus quadricauda

Apart from their functions in the nervous system of animals, neurotransmitters operate as regulatory agents and signals in diverse kingdoms of life. Some neurotransmitters have recently been revealed to exert specific effects on microalgae, predominantly functioning as algal growth stimulators. This article presents new data on the effects of such neurotransmitters as serotonin, norepinephrine, dopamine, histamine, and acetylcholine on the fatty acid and pigment composition of the green microalga Scenedesmus quadricauda (Turp.) Breb. K-1149. It was established that acetylcholine and, to a lesser extent, histamine increased the total fatty acid content of S. quadricauda cells, whereas serotonin and dopamine decreased the fatty acid content. Acetylcholine, histamine, and norepinephrine elevated the percentage of polyunsaturated fatty acids; in contrast, serotonin and dopamine increased the share of saturated fatty acids. Acetylcholine and, to a lesser extent, norepinephrine increased the total chlorophyll content per gram of dry weight in S. quadricauda, while histamine decreased the chlorophyll content. Histamine also increased the chlorophyll a/chlorophyll b and carotenoid/chlorophyll ratios, which were decreased by dopamine. The data obtained are of biotechnological and ecological interest. The stimulation of fatty acid accumulation and the increase in the percentage of polyunsaturated species was caused by the neurotransmitters acetylcholine and histamine at low (1–10 μM) concentrations, which potentially enables facilitating the biotechnological production of health-promoting preparations for therapeutic and cosmetic purposes. However, other neurotransmitters (dopamine and serotonin) tested increased the relative content of saturated fatty acids; therefore, they apparently can be used to stimulate biofuel production, since saturated fatty acid-rich lipids are advantageous raw materials for biodiesel production. The impact of neurotransmitters on microalgal fatty acid composition and photosystem components may be considered in terms of ongoing chemical interaction between microalgae and other aquatic ecosystem components that are known to produce neurotransmitters.

Raman analysis of aqueous solutions of ethylene glycol and 1,3-propylene glycol: Fundamental and applied aspects

Aqueous solutions of glycols, on the one hand, are widely used in many applications; on the other hand, they can serve as simple and representative models for studying intra- and intermolecular hydrogen bonds. In this work, we analyze the possibilities and limitations of Raman spectroscopy for fundamental and applied researches of such solutions on the examples of ethylene glycol (EG) and 1,3-propylene glycol (1,3-PG). It is shown that Raman spectroscopy is an effective tool for monitoring temporal changes in the structure of glycol solutions deposited on substrates. This study demonstrates that the water content in the solutions on the substrates decreases rapidly with time, and the rate of this decrease depends on the chemical structure of both glycol and substrate. It was found that the reduction in the water content leads to slight decrease in the contents of gauche-conformers in the backbones of EG and 1,3-PG molecules. It is shown that use of the 1064 nm excitation ensures a reliable Raman analysis of automotive antifreezes containing various dyes, in particular determination of the relative contents of water and glycol.

Mechanical and shrinkage properties of alkali-activated mortars with graphite tailings

To improve the problems of high CO2 emission generated by the preparation of silicate cement, large accumulation of solid waste, and depletion of natural sand resources, this paper investigates the effect of pozzolanic effect of graphite tailings (GT) on the mechanical properties, shrinkage properties and microstructure of alkali-activated mortar, and less research has been done on this related content. This paper partially replaced the natural sand with GT, and completely replaced the cement with fly ash and slag to prepare alkali-activated fly ash-slag (AAFS) mortar. The consequences of GT replacement rate on the mechanical and shrinkage characteristics of AAFS mortar were analyzed. In addition, X-ray diffraction (XRD), mercury-in-pressure (MIP), and nuclear magnetic resonance (29Si MAS NMR) were used to examine the hydration degree, pore structure, and hydration products of AAFS mortar. The results demonstrated when the Na2O content was 7 % and the activator modulus was 1.0, the test group's 28-day flexural and compressive strengths at a 20 % GT replacement rate were increased by 19.49 % and 14.45 %, respectively, compared to the test group without GT. The appropriate quantity of GT reduced the AAFS mortar's drying shrinkage and increased the AAFS mortar's self-shrinkage. According to the microstructure analysis, GT had a pozzolanic effect: moderate doping of GT promoted the hydration reaction of precursors, improved the amount of C-(A)-S-H gel product generated, and improved AAFS mortar's mechanical and shrinkage properties.

Evaluating potential phytotoxicity of erythritol solution, a novel control method for Drosophila suzukii, in blueberry, cherry, and wild Himalayan blackberry

Drosophila suzukii, commonly referred to as spotted-wing drosophila, is a recent pest of small and stone fruits across the United States. While its control is commonly achieved through broad-spectrum pesticides, these chemicals are often harmful to beneficial insects. A new candidate for control is erythritol, a non-nutritive sugar alcohol with insecticidal properties. Erythritol solutions with a sucrose (E:S) or sucralose (E:Sul) phagostimulant reduce larval infestation and deter oviposition when applied to fruits pre-harvest, but lead to spotting and other damage to sprayed plant leaves. Our objectives were to determine the extent and physiological impacts of the damage in several plant systems and assess the role of individual components in potential phytotoxicity. In the first year, bulk or lab-grade erythritol were combined with a sucrose or sucralose phagostimulant to evaluate the effects of the solutions and a water control on visible damage, stomatal conductance, chlorophyll fluorescence, relative water content, and osmolality in blueberry, cherry, and blackberry leaves. When bulk erythritol did not have discernible impacts, second year trials evaluated solutions of lab-grade erythritol with a phagostimulant and solutions of individual chemicals on leaf damage and physiological factors. Solutions of E:S and E:Sul caused the greatest visible damage, but damage was highly variable between years, treatments, and plant systems. There were no consistent plant physiological effects associated with any formulation. These results suggest that while visible leaf damage may be a dose-dependent effect of erythritol solutions, the lack of associated physiological impacts make it a viable candidate for further testing.

Manure-biochar compost mitigates the soil salinity stress in tomato plants by modulating the osmoregulatory mechanism, photosynthetic pigments, and ionic homeostasis

One of the main abiotic stresses that affect plant development and lower agricultural productivity globally is salt in the soil. Organic amendments, such as compost and biochar can mitigate the opposing effects of soil salinity (SS) stress. The purpose of this experiment was to look at how tomato growth and yield on salty soil were affected by mineral fertilization and manure-biochar compost (MBC). Furthermore, the study looked at how biochar (organic amendments) work to help tomato plants that are stressed by salt and also a mechanism by which biochar addresses the salt stress on tomato plants. Tomato yield and vegetative growth were negatively impacted by untreated saline soil, indicating that tomatoes are salt-sensitive. MBC with mineral fertilization increased vegetative growth, biomass yield, fruit yield, chlorophyll, and nutrient contents, Na/K ratio of salt-stressed tomato plants signifies the ameliorating effects on tomato plant growth and yield, under salt stress. Furthermore, the application of MBC with mineral fertilizer decreased H2O2, but increased leaf relative water content (RWC), leaf proline, total soluble sugar, and ascorbic acid content and improved leaf membrane damage, in comparison with untreated plants, in response to salt stress. Among the composting substances, T7 [poultry manure-biochar composting (PBC) (1:2) @ 3 t/ha + soil-based test fertilizer (SBTF)] dose exhibited better-improving effects on salt stress and had maintained an order of T7 > T9 > T8 > T6 in total biomass and fruit yield of tomato. These results suggested that MBC might mitigate the antagonistic effects of salt stress on plant growth and yield of tomatoes by improving osmotic adjustment, antioxidant capacity, nutrient accumulation, protecting photosynthetic pigments, and reducing ROS production and leaf damage in tomato plant leaves.