Physiological Approaches Research Articles

Evaluation of drought and salinity tolerance potentials of different soybean genotypes based upon physiological, biochemical, and genetic indicators

The present study has evaluated different soybean genotypes to understand the salt and drought tolerance mechanisms based on physiological traits (photosynthesis, stomatal conductance, chlorophyll, and cell membrane stability), antioxidant enzymes (superoxide dismutase, catalase, and peroxidase), reactive oxygen species (H2O2 and O2•−), osmolytes (glycine betaine, proline, and Na+/K+), plant water relations (relative water content, water potential, and solute potential) and expression of related genes (GmCAT1, GmPOD1, GmSOD, GmP5CS, GmNHX1, GmAKT1, GmDREB1, and GmARF1). The experiment was conducted in a two-factorial arrangement using randomized complete block design (RCBD) with genotypes as one factor and salt, drought, and control treatments as the other factor. All physiological traits, relative water content, and water potential decreased significantly in all soybean genotypes due to individual and combined treatments of drought and salt stress, with significantly less decrease in soybean genotypes G4620RX, DM45X61, and NARC-21. Besides that, the activity of antioxidant enzymes, production of ROS, accumulation of osmolytes, solute potential, and Na+/K+ ratio were increased significantly in all soybean genotypes under salt and water deficit conditions. As a whole, the soybean genotypes G4620RX, DM45X61, and NARC-21 showed the maximum enzymatic activity with less increase in ROS and Na+/K+ in addition to a high accumulation of osmolytes and an increase in solute potential. Correspondingly, the genotypes exhibiting high physiological and biochemical tolerance to drought and salt stresses showed the high expression of genes imparting the stress tolerance. Moreover, correlation, heatmap, and principal component analysis further confirmed the varying physiological and biochemical responses of all soybean genotypes under individual and combined applications of drought and salinity stresses. Overall, the present study confirmed that plants opt for the integrated physiological, biochemical, and genetic approaches to counteract the harmful effects of environmental stresses.

Supra- and sub-threshold intracellular-like recording of 2D and 3D neuronal networks using nanopillar electrode arrays

The brain integrates activity across networks of interconnected neurons to generate behavioral outputs. Several physiological and imaging-based approaches have been previously used to monitor responses of individual neurons. While these techniques can identify cellular responses greater than the neuron’s action potential threshold, less is known about the events that are smaller than this threshold or are localized to subcellular compartments. Here we use NEAs to obtain temporary intracellular access to neurons allowing us to record information-rich data that indicates action potentials, and sub-threshold electrical activity. We demonstrate these recordings from primary hippocampal neurons, induced pluripotent stem cell-derived (iPSC) neurons, and iPSC-derived brain organoids. Moreover, our results show that our arrays can record activity from subcellular compartments of the neuron. We suggest that these data might enable us to correlate activity changes in individual neurons with network behavior, a key goal of systems neuroscience.

Sulfuric acid effects in seed dormancy break of Ipomoea batatas evaluated by enzymatic, anatomic and physiological approaches

ABSTRACT The recommended method to overcome seed coat dormancy in sweet potato seeds is exposure to sulfuric acid, which can damage the embryo and affect seedling development depending on exposure time. This study aimed to determine the ideal immersion period using physiological, anatomical, and enzymatic analyses. Seeds were scarified with concentrated sulfuric acid for nine immersion periods. Physiological analyses included germination tests, germination speed index, first germination count, emergence test, and emergence speed index. Image analysis quantified the primary root length, root-to-hypocotyl ratio, and seedling length. Catalase and superoxide dismutase enzyme activities were analysed. Seed coat anatomy, including thickness, wear, and colour, was also assessed. Exposure to sulfuric acid for 30 min effectively broke dormancy without impacting the antioxidant system or seedling development. Thermal chambers confirmed that chemically scarified seeds absorb water and activate metabolism faster. Plant anatomy helped illustrate how sulfuric acid breaks dormancy by eroding physical barriers.

PagbZIP75 decreases the ROS accumulation to enhance salt tolerance of poplar via the ABA signaling

Poplar (Populus L.) is a fast-growing economic timber plant that is susceptible to salt stress. Here, PagbZIP75 (Potri.014G120800), which was isolated from 84 K poplar and upregulated in response to salt treatment, was investigated by generating overexpression (OE) and repression (RNAi) transgenic lines to elucidate its role in poplar salt stress tolerance through molecular and physiological approaches. PagbZIP75 localized in the nucleus and cell membrane but lacked transcriptional activation activity in yeast cells. Expression pattern analysis revealed that PagbZIP75 was induced by salt stress, peaking at 12 hours in roots and stems and 24 hours in leaves. Under salt stress, OE exhibited enhanced growth and a more robust root system compared to non-transgenic 84 K poplar (WT) and RNAi. DAB and NBT staining results demonstrated lower levels of reactive oxygen species (ROS) in OE leaves, alongwith reduced electrolyte leakage rate and superoxide anion (O2-) content, while the proline content and superoxide dismutase (SOD) activity were significantly elevated under salt stress. Based on the RNA-seq data, multilayered hierarchical gene regulatory network (ML-hGRN) around bZIP75 was illustrated and indicated that PagbZIP75 was induced by ABA hormone along with 10 salt-related co-expressed genes. Yeast one-hybrid (Y1H) experiments indicated the binding of PagAREB1 protein to the 0–208 bp upstream fragments of PagbZIP75, and dual luciferase assays (LUC) confirmed a negative interaction between AREB1 and bZIP75. Overall, this study provides a theoretical foundation for the enhancement of poplar salt tolerance by PagbZIP75 through the reduction of ROS accumulation via ABA signaling.

The resonance of seen things: Seeing the Virgin Mary in the concrete

AbstractWhat follows is an exploration of an experience of seeing. The experience of interest here is the seeing of Our Lady of the Underpass, a Marian apparition that was seen in an underpass in Chicago in early 2005. Taking the images and objects brought to the make‐shift shrine as clues, we explore the constitutive poetic resonances ingredient to this seeing. We point to how these constitutive poetic resonances function both as an explanation of and as instructions for the seeing of the Virgin Mary in the underpass. We then consider how the semiotic multimodality of these poetic resonances made this seeing so robust, paying particular attention to the historical dimension of seeing. The resulting analysis offers the outlines of a cultural historical onto‐poetic approach that builds and expands upon existing physiological approaches to seeing by highlighting the essential role of social, cultural, and historical contexts for seeing.

Physiological and Biotechnological Approaches in Enhancing Quality Parameters of Chilli (Capsicum annuum L.)

Physiological approaches play a crucial role in optimizing the plant growth, yield and quality parameters in chilli cultivation. Some key physiological approaches and their influence on quality parameters are stress induction (water and salt stress), hormonal treatment and nutrient management (organic and inorganic fertilizers). These physiological approaches helps chilli growers to meet market demands and consumer preferences more effectively. Biotechnological approaches also can bring major improvements in the quality aspects of chilly. Also the optimization of yield and quality contributes to the economic success of chili cultivation, providing consumers with high-quality products and producers with sustainable production systems.

The Multifunctional Anaphase Promoting Complex 7 (APC7) Gene Is Associated With Increased Plant Growth and Improved Resistance to DNA and RNA Viruses.

The anaphase promoting complex 7 (AtAPC7) is an APC/C subunit expressed in different organs of Arabidopsis thaliana and conserved among eukaryotes. A variant of the complete APC7 protein, containing its C-terminal region (named APC-CT), shows a high homology with a tobacco viral replication inhibitor (IVR-like) protein that reduces plant susceptibility to RNA viruses. Here, the role of the AtAPC7 gene was investigated by characterizing Arabidopsis plants overexpressing the full-length AtAPC7 (APC7OE) and the C-terminal portion (APC7-CTOE), by phenotypical, physiological and molecular approaches. APC7OE plants showed improved growth of vegetative organs, earlier flowering and increased photosynthetic efficiency, CO2 assimilation and productivity, compared with Col-0 control plants. Conversely, APC7-CTOE plants showed reduced susceptibility to both RNA and DNA viruses, along with an improvement in plant growth, although not surpassing APC7OE plants. Altogether, the data provide evidence for the role of the AtAPC7 in regulating cell division, expansion and differentiation, accompanied by an increase in photosynthetic capacity, resulting in enhanced plant biomass and seed yield. AtAPC7-CT might reduce growth-defence trade-offs, enabling plants to simultaneously defend themselves while promoting better growth. Our findings highlight the multifunctional role of AtAPC7, unveiling the potential of its orthologous genes as valuable biotechnological tools in important crops.

Identifying Drought Tolerant Genotypes in Okra with Physiological and Molecular Approaches

Identifying Drought Tolerant Genotypes in Okra with Physiological and Molecular Approaches

Genetically defined neuron types underlying visuomotor transformation in the superior colliculus.

The superior colliculus (SC) is a conserved midbrain structure that is important for transforming visual and other sensory information into motor actions. Decades of investigations in numerous species have made the SC and its nonmammalian homologue, the optic tectum, one of the best studied structures in the brain, with rich information now available regarding its anatomical organization, its extensive inputs and outputs and its important functions in many reflexive and cognitive behaviours. Excitingly, recent studies using modern genomic and physiological approaches have begun to reveal the diverse neuronal subtypes in the SC, as well as their unique functions in visuomotor transformation. Studies have also started to uncover how subtypes of SC neurons form intricate circuits to mediate visual processing and visually guided behaviours. Here, we review these recent discoveries on the cell types and neuronal circuits underlying visuomotor transformations mediated by the SC. We also highlight the important future directions made possible by these new developments.

Cytological, physiological, and transcriptomic analyses reveal potential regulatory mechanisms of curly leaves in Tartary buckwheat

Tartary buckwheat (Fagopyrum tataricum Gaertn.) is a pseudocereal crop grown in sunny areas at high altitudes. To achieve high yield, this species is often densely planted. It is believed that moderately curly and upright leaves are beneficial for increasing the photosynthetic efficiency of a densely planted crop. However, little research on curly leaves has been reported for this species. The study reported here analyzed two EMS mutants Xi5M and P10M with curly and upright leaves using cytological, physiological, and transcriptomic approaches. Results showed that compared with their respective wild types, transpiration rate, stomatal conductance, net photosynthetic rate, and yield of effective quantum of photosystem Ⅱ were all increased in both mutants. The number of chloroplasts increased, and the number of granum lamellas was increased, and more tightly connected. These changes led to increased photosynthetic pigment contents in mutants. The unbalanced arrangement of upper and lower epidermal cells led to leaf curling in the mutants. The transcriptomic analysis detected 510 genes that were differentially expressed between both of the mutants and their respective wild types (i.e., Xi5M vs Xi5, and P10M vs PP10). They were mainly enriched in plant-pathogen interaction, plant hormone signal transduction, MAPK signaling pathway, phenylpropanoid biosynthesis, and ABC transporters. Analyses of leaf characteristics, function annotation of the differentially expressed genes (DEGs), and protein-protein interaction networks revealed 12 candidate genes which, by regulating cell development and plant hormone response, potentially regulated leaf curliness. Our study developed new leaf-shaped materials that could be valuable in enhancing the yield of Tartary buckwheat by improving population photosynthetic efficiency and revealed potential mechanisms of leaf curliness in this species.

Mineral imbalance and cardiovascular disease in animals of the canine (Canidae) and feline (Felidae) families: a study in Russian zoos

It is important to consider the full spectrum of complex interactions between mineral elements and biologically active substances to evaluate the development of cardiovascular disease (CVD) in animals, in addition to the classical physiological approach. This study aimed to assess changes in mineral element levels in wild and exotic animals in relation to their cardiovascular diseases. A total of 171 animals, including 128 healthy and 43 sick animals from three Russian zoos, were sampled and analyzed. For the first time, species from the canine (nine) and feline (seven) families from Moscow, Ivanovo, and Yaroslavl zoos in the Central Federal District of Russia were selected. A total of 108 samples from canines and 63 samples from feline animals were collected. Mineral element measurements were conducted on 1026 samples via a "Kvant-2A" atomic absorption spectrometer from Russia. Correlation and regression analyses were performed. CVDs were found in 10.1% of the studied animals, with a high percentage of heart muscle pathologies noted (25.8% of all CVDs). Iron (Fe) accumulated in canine and feline fur at approximately 208 and 203 mg/kg, with variations of 72.8% and 80.9%, respectively. A significant decrease in Fe and an increase in cadmium (Cd) during CVD were observed (correlations r = 0.25 and r = 0.16, respectively). The dysregulation of Fe homeostasis, increased absorption, and accumulation of Fe in the reticuloendothelial system are discussed. Finally, the mineral elements absorbed by canine and feline fur can be ranked in descending order: Fe > Zn > Cu > Pb > Cd > As.

High-temperature stress in strawberry: understanding physiological, biochemical and molecular responses.

Heat stress reduces strawberry growth and fruit quality by impairing photosynthesis, disrupting hormone regulation, and altering mineral nutrition. Multi-omics studies show extensive transcriptional, post-transcriptional, proteomic and metabolomic under high temperatures. Garden strawberry is a globally cultivated, economically important fruit crop highly susceptible to episodic heat waves and chronically rising temperatures associated with climate change. Heat stress negatively affects the growth, development, and quality of strawberries. Elevated temperatures affect photosynthesis, respiration, water balance, hormone signaling, and carbohydrate metabolism in strawberries. Heat stress reduces the size and number of leaves, the number of crowns, the differentiation of flower buds, and the viability of pollen and fruit set, ultimately leading to a lower yield. On a physiological level, heat stress reduces membrane stability, increases the production of reactive oxygen species, and reduces the antioxidant capacity of strawberries. Heat-tolerant varieties have better physiological and biochemical adaptation mechanisms compared to heat-sensitive varieties. Breeding heat-tolerant strawberry cultivars involves selection for traits such as increased leaf temperature, membrane thermostability, and chlorophyll content. Multi-omics studies show extensive transcriptional, post-transcriptional, proteomic, metabolomic, and ionomic reprogramming at high temperatures. Integrative-omics approaches combine multiple omics datasets to obtain a systemic understanding of the responses to heat stress in strawberries. This article summarizes the deciphering of strawberry responses to heat stress using physiological, biochemical, and molecular approaches that will enable the development of resilient adaptation strategies that sustain strawberry production under global climate change.

Sustained caloric restriction potentiates insulin action by activating prostacyclin synthase.

Caloric restriction (CR) is known to enhance insulin sensitivity and reduce the risk of metabolic disorders; however, its molecular mechanisms are not fully understood. This study aims to elucidate specific proteins and pathways responsible for these benefits. We examined adipose tissue from participants in the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE 2) study, comparing proteomic profiles from individuals after 12 and 24 months of CR with baseline and an ad libitum group. Biochemical and cell-specific physiological approaches complemented these analyses. Our data revealed that CR upregulates prostacyclin synthase (PTGIS) in adipose tissue, an enzyme crucial for producing prostacyclin (PGI2). PGI2 improves the ability of insulin to stimulate the tether-containing UBX domain for GLUT4 (TUG) cleavage pathway, which is essential for glucose uptake regulation. Additionally, iloprost, a PGI2 analog, was shown to increase insulin receptor density on cell membranes, increasing glucose uptake in human adipocytes. CR also reduces carbonylation of GLUT4, a modification that is detrimental to GLUT4 function. CR enhances insulin sensitivity by promoting PTGIS expression and stimulating the TUG cleavage pathway, leading to increased GLUT4 translocation to the cell surface and decreased GLUT4 carbonylation. These findings shed light on the complex molecular mechanisms through which CR favorably impacts insulin sensitivity and metabolic health.

Harnessing Nitrogen Use Efficiency for Enhancing Productivity in Rice: A Review

Nitrogen fertilizers have significantly enhanced rice yields over the past decades, but they also have substantial negative impacts on the environment. Excessive application of nutrients, particularly nitrogen, beyond crop requirements is linked to environmental losses. High nitrogen fertilizer input leads to low nitrogen use efficiency (NUE) due to the rapid loss of nitrogen through ammonia volatilization, denitrification, surface runoff, and leaching in the soil-flood water system. Enhancing the yield potential of rice- based cropping systems in response to the global call for carbon neutrality is a crucial research target. New approaches are needed to boost yields while maintaining or ideally reducing nitrogen application to maximize crop NUE. Improving NUE is crucial for addressing the intertwined challenges of environmental degradation, climate change, and food security. This review provides an in-depth exploration of strategies for improving nitrogen use efficiency, including soil health management, optimized fertilizer application, crop management practices, physiological and morphological approaches, exploiting symbiotic relationships, and genetic approaches, all aimed at enhancing rice productivity while addressing agricultural and environmental challenges caused by nitrogen losses, such as ammonia volatilization and leaching and promoting more sustainable farming practices. It also reduces the input costs, leading to a more sustainable agricultural economy and improved living standards for farming communities.

The integrative biology of the heart: mechanisms enabling cardiac plasticity.

Cardiac phenotypic plasticity, the remodelling of heart structure and function, is a response to any sustained (or repeated) stimulus or stressor that results in a change in heart performance. Cardiac plasticity can be either adaptive (beneficial) or maladaptive (pathological), depending on the nature and intensity of the stimulus. Here, we draw on articles published in this Special Issue of Journal of Experimental Biology, and from the broader comparative physiology literature, to highlight the core components that enable cardiac plasticity, including structural remodelling, excitation-contraction coupling remodelling and metabolic rewiring. We discuss when and how these changes occur, with a focus on the underlying molecular mechanisms, from the regulation of gene transcription by epigenetic processes to post-translational modifications of cardiac proteins. Looking to the future, we anticipate that the growing use of -omics technologies in integration with traditional comparative physiology approaches will allow researchers to continue to uncover the vast scope for plasticity in cardiac function across animals.

Light modulates glucose and lipid homeostasis via the sympathetic nervous system.

Light is an important environmental factor for vision, and for diverse physiological and psychological functions. Light can also modulate glucose metabolism. Here, we show that in mice, light is critical for glucose and lipid homeostasis by regulating the sympathetic nervous system, independent of circadian disruption. Light deprivation from birth elicits insulin hypersecretion, glucagon hyposecretion, lower gluconeogenesis, and reduced lipolysis by 6-8 weeks, in male, but not, female mice. These metabolic defects are consistent with blunted sympathetic activity, and indeed, sympathetic responses to a cold stimulus are significantly attenuated in dark-reared mice. Further, long-term dark rearing leads to body weight gain, insulin resistance, and glucose intolerance. Notably, metabolic dysfunction can be partially alleviated by 5 weeks exposure to a regular light-dark cycle. These studies provide insight into circadian-independent mechanisms by which light directly influences whole-body physiology and inform new approaches for understanding metabolic disorders linked to aberrant environmental light conditions.

The role of salicylic acid in modulating phenotyping in spring wheat varieties for mitigating drought stress

Climate change-related droughts that recur frequently are one of the biggest obstacles to wheat (Triticum aestivum L.) productivity. Worldwide, attempts are being done to establish drought-resistant cultivars. However, progress is slow since drought tolerance is a complex trait controlled by numerous genes, and its expression is influenced by the environment. Phenotypic, biochemical physiological, and genotyping approaches are highlighted as critical research components for leveraging genetic variation in eight wheat genotypes. Treatments included eight spring wheat genotypes (IPK_040, IPK_046, IPK_050, IPK_071, IPK_105, WAS_007, WAS_024 and WAS_031), normal irrigation (NI), drought stress (D) (30% field capacity (FC)), normal irrigation with 0.5 mM SA (NSA), and drought treated with SA (DSA). The results revealed that there was a reduction in relative water content, an increase membrane leakage, and leaf chlorophyll content under drought stress. SA induced the defense responses against drought by increasing the osmolytes and the antioxidative enzymes activities. Compared to the NI group, the DSA treatment improved the water regulation, antioxidant capacity, and drought stress resistance. SA significantly reduced the deleterious effects of water stress on phenotyping more in WAS_ 024 and IPK_ 105 genotypes. The most responsive genotypes to salicylic acid were IPK_ 046 among the IPK genotypes, whereas WAS_031 genotype was amongst WAS genotypes based on the morpho-physiological traits. The findings of this study give a solid foundation for assessing drought resistance in T. aestivum and developing cultivation-specific water management methods.Graphical

Combined transcriptome and physiological analysis reveals exogenous sucrose enhances photosynthesis and source capacity in foxtail millet

Foxtail millet (Setaria italica (L.) P. Beauv.) is an environmentally friendly crop that meets the current requirements of international food security and is widely accepted as a photosynthesis research model. However, whether exogenous sucrose treatment has a positive effect on foxtail millet growth remains unknown. Here, we employed physiological and molecular approaches to identify photosynthesis and source capacity associated with exogenous sucrose during the growth of Jingu 21 seedlings. RNA-seq analysis showed that some differentially expressed genes (DEGs) related to photosynthesis and carotenoid biosynthesis were induced by exogenous sucrose and that most of these genes were up-regulated. An increase in gas exchange parameters, chlorophyll content, and chlorophyll fluorescence of Jingu 21 was noted after exogenous sucrose addition. Furthermore, exogenous sucrose up-regulated genes encoding sucrose and hexose transporters and enhanced starch and sucrose metabolism. More DEGs were up-regulated by sucrose, the nonstructural carbohydrate (NSC) content in the leaves increased and energy metabolism and sucrose loading subsequently improved, ultimately enhancing photosynthesis under normal and dark conditions. Further analysis revealed that WRKYs, ERFs, HY5, RAP2, and ABI5 could be key transcription factors involved in growth regulation. These results indicate that exogenous sucrose affects the normal photosynthetic performance of foxtail millet by increasing NSC transport and loading. They improve our understanding of the molecular mechanisms of the effects of exogenous sucrose on photosynthesis in foxtail millet, providing an effective measure to enhance source–sink relationships and improve yield.

Thiol Stress Fuels Pyrazinamide Action Against Mycobacterium tuberculosis.

Pyrazinamide (PZA) is a cornerstone of first-line antitubercular drug therapy and is unique in its ability to kill nongrowing populations of Mycobacterium tuberculosis through disruption of coenzyme A synthesis. Unlike other drugs, PZA action is conditional and requires potentiation by host-relevant environmental stressors, such as low pH and nutrient limitation. Despite its pivotal role in tuberculosis therapy, the mechanistic basis for PZA potentiation remains unknown and the durability of this crucial drug is challenged by the emergent spread of drug resistance. To advance our understanding of PZA action and facilitate discovery efforts, we characterized the activity of a more potent PZA analog, morphazinamide (MZA). Here, we demonstrate that like PZA, MZA acts in part through impairment of coenzyme A synthesis. Unexpectedly, we find that, in contrast to PZA, MZA does not require potentiation due to aldehyde-mediated disruption of thiol metabolism and maintains bactericidal activity against PZA-resistant strains. Our findings reveal a novel dual action mechanism of MZA that synergistically disrupts coenzyme A synthesis resulting in a faster rate of killing and a higher barrier to resistance relative to PZA. Together, these observations resolve the mechanistic basis for potentiation of a key first-line antitubercular drug and provide new insights for discovery of improved therapeutic approaches for tuberculosis.

Xyloglucan endotransglucosylase-hydrolase 1 is a negative regulator of drought tolerance in barley via modulating lignin biosynthesis and stomatal closure

The projected increase in drought severity and duration worldwide poses a significant threat to crop growth and sustainable food production. Xyloglucan endotransglucosylase/hydrolases (XTHs) family is essential in cell wall modification through the construction and restructuring of xyloglucan cross-links, but their role in drought tolerance and stomatal regulation is still illusive. We cloned and functionally characterized HvXTH1 using genetic, physiological, biochemical, transcriptomic and metabolomic approaches in barley. Evolutionary bioinformatics showed that orthologues of XTH1 was originated from Streptophyte algae (e.g. some species in the Zygnematales) the closest clade to land plants based on OneKP database. HvXTH1 is highly expressed in leaves and HvXTH1 is localized to the plasma membrane. Under drought conditions, silencing HvXTH1 in drought-tolerant Tibetan wild barley XZ5 induced a significant reduction in water loss rate and increase in biomass, however overexpressing HvXTH1 exhibited drought sensitivity with significantly less drought-responsive stomata, lower lignin content and a thicker cell wall. Transcriptome profile of the wild type Golden Promise and HvXTH1-OX demonstrated that drought-induced differentially expressed genes in leaves are related to cell wall biosynthesis, abscisic acid and stomatal signaling, and stress response. Furthermore, overexpressing HvXTH1 suppressed both genes and metabolites in the phenylpropanoid pathway for lignin biosynthesis, leading to drought sensitivity of HvXTH1-OX. We provide new insight by deciphering the function of a novel protein HvXTH1 for drought tolerance in cell wall modification, stomatal regulation, and phenylpropanoid pathway for lignin biosynthesis in barley. The function of HvXTH1 in drought response will be beneficial to develop crop varieties adapted to drought.