Physiological Regulation Research Articles

Beyond Lux: methods for species and photoreceptor-specific quantification of ambient light for mammals.

Light is a key environmental regulator of physiology and behaviour. Mistimed or insufficient light disrupts circadian rhythms and is associated with impaired health and well-being across mammals. Appropriate lighting is therefore crucial for indoor housed mammals. Light is commonly measured in lux. However, this employs a spectral weighting function for human luminance and is not suitable for 'non-visual' effects of light or use across species. In humans, a photoreceptor-specific (α-opic) metrology system has been proposed as a more appropriate way of measuring light. Here we establish technology to allow this α-opic measurement approach to be readily extended across mammalian species, accounting for differences in photoreceptor types, photopigment spectral sensitivities, and eye anatomy. We develop a high-throughput method to derive spectral sensitivities for recombinantly expressed mammalian opsins and use it to establish the spectral sensitivity of melanopsin from 13 non-human mammals. We further address the need for simple measurement strategies for species-specific α-opic measures by developing an accessible online toolbox for calculating these units and validating an open hardware multichannel light sensor for 'point and click' measurement. We finally demonstrate that species-specific α-opic measurements are superior to photopic lux as predictors of physiological responses to light in mice and allow ecologically relevant comparisons of photosensitivity between species. Our study presents methods for measuring light in species-specific α-opic units that are superior to the existing unit of photopic lux and holds the promise of improvements to the health and welfare of animals, scientific research reproducibility, agricultural productivity, and energy usage.

Intestinal stem cell niche: An upcoming area of immense importance in gastrointestinal disorders.

The intestinal stem cell (ISC) niche is vital for maintaining the integrity and function of the intestinal epithelium. ISC populations, characterized by their high proliferation and multipotency, reside within a specialized microenvironment at the base of crypts. Crypt base columnar (CBC) cells at the deepest part of crypts serve as replicating ISCs, while position 4 label-retaining cells (LRCs) located higher up in the crypts are also important for ISC maintenance during experiments. The interplay between CBCs, position 4 LRCs, transient amplifying (TA) cells and other niche components, including the pericrypt stromal cells, ensures a continuous supply of differentiated epithelial cells. Recent advancements in ISC biomarker studies have provided valuable insights into their molecular signatures, regulatory pathways and roles in the pathogenesis of intestinal disorders. Understanding the ISC niche has significant therapeutic implications, as manipulating ISC behaviors and regenerating damaged or diseased intestinal tissue show promise for novel therapeutic approaches. ISC organoids have also provided a platform for studying intestinal diseases and testing personalized therapies. This comprehensive review covers the anatomical composition, physiological regulation, ISC biomarker studies, contribution to intestinal disorder pathogenesis and potential therapeutic implications of the ISC niche.

Exogenous Riboflavin Application at Different Growth Stages Regulates Photosynthetic Accumulation and Grain Yield in Fragrant Rice

Fragrant rice has high market value and is popular among consumers because of its pleasant fragrance. Plant growth regulators and trace elements can influence the yield and physiological indices of fragrant rice. Riboflavin, a vital component of plant vitamins, plays a crucial role in plant growth and development, and it is a water-soluble vitamin that is essential for sustaining normal photosynthesis and metabolic processes. However, the effects of riboflavin on nutrient accumulation and yield formation in fragrant rice have rarely been reported. Therefore, to further increase the yield and quality of fragrant rice, this study investigated the impact of the foliar application of riboflavin at different growth stages on nutrient accumulation and yield formation in two different genotypes of fragrant rice via a pot experiment. The experimental design consisted of three treatment groups, i.e., the T0 treatment group (control), which was sprayed with water; the T1 treatment group, which was sprayed at the booting stage; and the T2 treatment group, which was sprayed at the flowering stage; in all of these groups, 20 mg·L−1 riboflavin solution was used. The results revealed that the yields of the T1 and T2 treatments increased by 6.56–7.25% and 10.52–13.80%, respectively, compared with those of T0, which was attributed mainly to the increase in 1000-grain weight and grain filling. Furthermore, foliar spraying of riboflavin significantly increased the chlorophyll content, which resulted in the increased production of more total starch, soluble sugars, and sucrose and facilitated their transportation to the seeds. Moreover, applying riboflavin directly to the leaves increased the activity levels of the sucrose synthase (SS) and sucrose phosphate synthase (SPS) enzymes. Among the three treatments, the T2 treatment had the most pronounced effect. The results revealed that the foliar application of riboflavin could increase photosynthesis and promote the production of nonstructural carbohydrates, thereby increasing the total aboveground biomass of fragrant rice by 17.00–20.91% and 21.07–72.91% under the T1 and T2 treatments, respectively. Additionally, spraying riboflavin promoted rapid increases in the weight of fragrant rice seeds. In conclusion, foliar spraying of riboflavin during the flowering stage of aromatic rice can effectively enhance photosynthetic accumulation and yield, which is a promising physiological regulation strategy and provides new theoretical guidance for high-yield cultivation practices.

17α-Ethynylestradiol alters testicular epigenetic profiles and histone-to-protamine exchange in mice

Spermatogenesis starts with the onset of puberty within the seminiferous epithelium of the testes. It is a complex process under intricate control of the endocrine system. Physiological regulations by steroid hormones in general and by estrogens in particular are due to their chemical nature prone to be disrupted by exogenous factors acting as endocrine disruptors (EDs). 17α-Ethynylestradiol (EE2) is an environmental pollutant with a confirmed ED activity and a well-known effect on spermatogenesis and chromatin remodeling in haploid germ cells. The aim of our study was to assess possible effects of two doses (2.5ng/ml; 2.5 μg/ml) of EE2 on both histone-to-protamine exchange and epigenetic profiles during spermatogenesis performing a multi/transgenerational study in mice. Our results demonstrated an impaired histone-to-protamine exchange with a significantly higher histone retention in sperm nuclei of exposed animals, when this process was accompanied by the changes of histone post-translational modifications (PTMs) abundancies with a prominent effect on H3K9Ac and partial changes in protamine 1 promoter methylation status. Furthermore, individual changes in molecular phenotypes were partially transmitted to subsequent generations, when no direct trans-generational effect was observed. Finally, the uncovered specific localization of the histone retention in sperm nuclei and their specific PTMs profile after EE2 exposure may indicate an estrogenic effect on sperm motility and early embryonic development via epigenetic mechanisms.

Health benefits and future research of phytochemicals: a literature review

Phytochemicals are non-nutritive substances found in plant foods that originally contribute significantly to the flavor and color of the foods. These substances are usually classified as polyphenols, terpenes, sulfur-containing compounds, nitrogen containing compounds and others. A large amount studies from last decades demonstrated that these substances have played an immeasurable role in physiological regulation, health care and disease prevention through the exerting actions of antioxidation, anti-inflammation, anti-ageing, anti-virus, anti-cancer, anti-thrombosis, regulating lipid profiles, cardiovascular protection, neuroprotection, immunity regulation and improving metabolic functions. This paper is intended to review the chemistry and biochemistry of phytochemicals as related to classification, chemical structure, their occurrence and biosynthesis in plants, and the biological activities and implications in human health and various diseases. The discussions are focused on important and most recent advances in the above aspects. Furthermore, some future research directions of phytochemicals are set forth in the aspects of the dose-response, the mechanism and targets, the interactions with gut microbiota, the impact on human health and different stages of chronic diseases.

Synergistic promotion mechanism and structure-function relationship of nonmetallic atoms doped carbon nanodots driving Tagetes patula L. to remediate cadmium-contaminated soils

Phytoremediation is an economical and effective strategy to remove cadmium (Cd) from polluted environments. To improve its efficiency, nanotechnology has been proposed to collaborate with hyperaccumulators in the remediation of Cd-polluted soils. However, the intricate structure-function relationship and the underlying regulatory mechanisms by which nanomaterials regulate Cd migration and conversion within the soil-plant system remained unrevealed. In this study, functional carbon nanodots (FCNs) were modified by doping with nitrogen and (or) sulfur elements. The synthesized nonmetallic atoms-doped FCNs were utilized to investigate their structure-function relationship and the regulatory mechanisms underlying their role in the phytoremediation of Cd-polluted soils by Tagetes patula L. FCNs-based nanomaterials can regulate the migration and bioaccumulation of Cd in the soil-plant system, which exhibits an obvious structural dependency. Specifically, the synergistic application of sulfur doped FCNs and Tagetes patula L. had the highest Cd removal efficiency of 53.2%, which was 20.1% higher than Tagetes patula L. alone. The uptake and migration of Cd in the soil-plant system are regulated by FCNs-based nanomaterials through both direct and indirect mechanisms, involving interfacial reactions, plant physiology regulation and environmental influence. This study not only sheds light on the fate of FCNs-based nanomaterials and Cd in the soil-plant system, but also provides innovative nanotools for reinforcing phytoremediation efficiency in contaminated soils.

Bidirectional Relations Among Maternal Positive Emotion, Infant Positive Emotionality, and Infant Physiological Regulation Across the First 18 Months of Life.

Respiratory sinus arrhythmia (RSA), a marker of self-regulation, has been linked to developmental outcomes in young children. Although positive emotions may have the potential to facilitate physiological self-regulation, and enhanced self-regulation could underlie the development of positive emotions in early childhood, the relation between positive emotions and physiological self-regulation in infancy has been relatively overlooked. The current study examined the bidirectional associations among maternal positive emotion, infant positive emotionality, and infant resting RSA across the first 18 months of life. We used data from the Longitudinal Attention and Temperament Study (LanTs; N=309 in the current analysis) to test the within- and between-person relations of study variables over time using a random-intercepts cross-lagged panel model. We found that infants with higher overall levels of positive emotionality also displayed greater resting RSA, and their mothers exhibited higher levels of positive emotion. However, there were negative cross-lagged associations within-person; higher than average infant positive emotionality predicted lower levels of infant resting RSA at the subsequent timepoint during early infancy, whereas higher than average infant RSA subsequently predicted decreased levels of infant positive emotionality later in infancy. Results highlight the importance of considering transactional relations between positive emotion and physiological self-regulation in infancy.

Direct vegetation response to recent CO2 rise shows limited effect on global streamflow

Global streamflow, crucial for ecology, agriculture, and human activities, can be influenced by elevated atmospheric CO2 (eCO2) though direct regulation of vegetation physiology and structure, which can either decrease or increase streamflow. Despite a 21.8% rise in CO2 over 40 years, its impact on streamflow is not obvious and remains highly debated. Using a full differential approach at the catchment scale and an optimum finger approach globally, both constrained by observed streamflow, here, we find that vegetation responses to eCO2 in 1981–2020 has limited impact on streamflow via direct regulation. The median eCO2 contribution approaches zero across 1116 unimpacted catchments, and global streamflow changes cannot be solely attributed to eCO2. These results offer key insights into the intricate dynamics of CO2 and other factors shaping streamflow changes over the past four decades. Such understanding is vital for attributing current streamflow changes under eCO2 conditions.

In Search of the Role of Three-Finger Starfish Proteins

Three-finger proteins (TFPs), or Ly6/uPAR proteins, are characterized by the beta-structural LU domain containing three protruding “fingers” and stabilized by four conserved disulfide bonds. TFPs were initially characterized as snake alpha-neurotoxins, but later many studies showed their regulatory roles in different organisms. Despite a known expression of TFPs in vertebrates, they are poorly studied in other taxa. The presence of TFPs in starfish was previously shown, but their targets and functional role still remain unknown. Here, we analyzed expression, target, and possible function of the Lystar5 protein from the Asterias rubens starfish using bioinformatics, qPCR, and immunoassay. First, the presence of Lystar5 homologues in all classes of echinoderms was demonstrated. qPCR revealed that mRNA of Lystar5 and LyAr2 are expressed mainly in coelomocytes and coelomic epithelium of Asterias, while mRNA of other TFPs, LyAr3, LyAr4, and LyAr5, were also found in a starfish body wall. Using anti-Lystar5 serum from mice immunized by a recombinant Lystar5, we confirmed that this protein is expressed on the surface of coelomocytes and coelomic epithelium cells. According to ELISA, a recombinant analogue of Lystar5 bound to the membrane fraction of coelomocytes and coelomic epithelium but not to the body wall or starfish arm tip. Analysis by LC-MALDI MS/MS suggested integrin α-8-like protein expressed in the coelomocytes and coelomic epithelium as a target of Lystar5. Thus, our insights propose the important role of TFPs in regulation of starfish physiology and show prospects for their further research.

Short-term exercise counteracts accelerated ageing impacts on physical performance and liver health in mice.

Senescence impairs liver physiology, mitochondrial function and circadian regulation, resulting in systemic metabolic dysregulation. Given the limited research on the effects of combined exercise on an ageing liver, this study aimed to evaluate its impact on liver metabolism, circadian rhythms and mitochondrial function in senescence-accelerated mouse-prone 8 (SAMP8) and senescence-accelerated mouse-resistant 1 (SAMR1) mice. Histological, reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunoblotting analyses were conducted, supplemented by transcriptomic data sets and AML12 hepatocyte studies. Sedentary SAMP8 mice exhibited decreased muscle strength, reduced mitochondrial complex I levels and increased lipid droplet accumulation. In contrast, combined exercise mitigated muscle strength loss, upregulated proteins involved in mitochondrial complexes (CIII, CIV, CV) and increased Bmal1 messenger RNA (mRNA) expression in the liver. These molecular adaptations are associated with healthier liver phenotypes and may influence metabolic function and cellular longevity. Notably, elevated lipid content in aged mice was reduced post-exercise, indicating liver benefits even after a relatively short intervention. The combined exercise regimen did not improve aerobic capacity, likely due to the low volume and brief duration of running. Moreover, no significant effects were observed in SAMR1 mice, possibly because the training intensity was insufficient for younger, healthier animals. These findings underscore the potential of combined strength and endurance exercise to attenuate age-related liver dysfunction, particularly in ageing populations.

Nr1d1 inhibition mitigates intermittent hypoxia-induced pulmonary hypertension via Dusp1-mediated Erk1/2 deactivation and mitochondrial fission attenuation

Intermittent hypoxia (IH) precipitates pulmonary vasoconstriction, culminating in the onset of pulmonary hypertension (PH) among individuals afflicted with sleep apnea. While Nuclear receptor subfamily 1 group D member 1 (Nr1d1) is progressively recognized as pivotal regulator of cellular physiology, the role in the pathogenesis of IH-induced PH remains largely uncharted. The expression of Nr1d1 was examined in IH-induced rodent PH and in IH-treated PASMCs. To elucidate the contribution of Nr1d1 to the development of IH-induced PH, we employed siRNA to modulate Nr1d1 expression in vitro and employed serotype 1 adeno-associated virus (AAV1) in vivo. Nr1d1 levels were elevated in IH-induced rodents PH lung tissues and IH-treated PASMCs. Knocking down Nr1d1 by AAV1 effectively inhibited PH progression in chronic IH-induced PH models. Mechanistic investigations identified dual specificity phosphatase 1 (Dusp1), as a direct target that Nr1d1 trans-repressed, mediating Nr1d1’s regulatory influence on Erk1/2/Drp1 signaling. Nr1d1 deficiency ameliorates mitochondrial dysfunction and fission by restoring Dusp1 dysregulation and Drp1 phosphorylation. Activation of Erk1/2 with PMA reversed the Dusp1-mediated regulation of Drp1 phosphorylation, indicating the involvement of the Erk1/2 pathway in Drp1 phosphorylation controlled by Dusp1. Meanwhile, intermittent hypoxia induced more severe PH in Dusp1 knockout mice compared with wild-type mice. Our data unveil a novel role for Nr1d1 in IH-induced PH pathogenesis and an undisclosed Nr1d1-Dusp1 axis in PASMCs mitochondrial fission regulation.

Sphingosine-1-phosphate reduces arterial thrombosis via enhanced endothelial thrombomodulin expression by S1PR1 signaling

Abstract Background Sphingosine 1-phosphate (S1P) is an important lipid mediator in the cardiovascular system. Numerous links between S1P and blood coagulation have been described. However, results regarding the role of S1P in coagulation are inconclusive. A physiological antithrombotic regulator expressed by endothelial cells (EC) is thrombomodulin (TM). To date, the impact of S1P on TM-expression is unknown. Methods We evaluated S1P effects on TM-expression and subsequent platelet adhesion and thrombus formation. For this, we conducted cell culture with human umbilical cord venous endothelial cells (HUVECs), flow cytometry and flow chamber experiments. Additionally, in vivo arterial thrombus formation in mice was analyzed. Results Sphingosine kinase-1 deficient mice (SphK1-/-) have about 70% less circulating plasma S1P and show a significant reduction in TM expression on the aorta as compared to their littermates (WT: 207.2 ± 45.8 pg/g Aorta vs. SphK1-/- 124.5 ± 40.2 pg/g Aorta, p<0.0001). In contrast, S1P incubation of 24 hours significantly increased TM-expression on HUVECs by about 30 percent. This effect was abolished by S1PR1-inhibition with W146. Treatment with S1P reduced platelet adhesion from whole blood to endothelial cells in the flow chamber experiments (Con: 100.00 ± 28.09% vs. S1P: 80.91 ± 22.85%, p<0.0001). This effect could be reversed both by S1PR1 inhibition and with a TM-neutralizing antibody. P-selectin-expression on platelets was decreased after incubation with TM suggesting (Ctrl: 62.79 ± 13.30% vs. TM: 43.47 ± 11.36%, p=0.0222). Finally, to assess the in vivo effects of our findings, arterial thrombus formation in mice was performed. TM inhibited in vivo thrombus formation. Occlusion of the carotid artery could not be detected during the 30 minutes recording. In contrast, SphK1-/- mice with low S1P levels showed decreased times to first occlusion. Treatment with TM in these animals was able to reverse this effect. Conclusion We can conclude that the main findings of our study were (i) S1P increased endothelial TM-expression, (ii) which subsequently leads to reduced platelet adhesion and (iii) inhibition of arterial thrombus formation in vivo.

Physiological regulation processes differentiate the experience of ruptures between patient and therapist.

The empirical and clinical literature emphasizes the importance of alliance ruptures, signaling therapeutic processes occurring within and between the partners of the therapeutic dyad. However, knowledge about the underlying regulatory processes that occur amid ruptures is scarce. Identifying the underlying physiological markers may shed light on these regulatory processes. The overarching goal of the present study was to explore physiological markers of withdrawal and confrontation ruptures, within the patient and the therapist. Given the little known on the subject, we used a single-case design (94 episodic segments) to explore biologically based regulatory processes in the face of a rupture, contrasting confrontation ruptures versus withdrawal ruptures versus control episodes (emotional and neutral episodes). Findings showed that the patient and the therapist had contrasting physiological responses to the ruptures, depending on the type. During withdrawal ruptures, the patient exhibited high regulation, while the therapist did not show a clear physiological reaction. During confrontation ruptures, the patient exhibited low regulation, while the therapist exhibited high regulation. The different physiological regulation processes at times of ruptures suggest that, in withdrawal, the patient relied on intrapersonal regulation, contrasting with the interpersonal regulation observed in confrontation ruptures. Findings remained robust after controlling for speech turns and 10,000 Monte Carlo permutations to assess chance-level results. These findings provide initial evidence for the link between arousal and behavior in ruptures, offering valuable psychoeducational material for therapists to improve their handling of these challenging moments. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Mechanisms of heavy metal-induced rhizosphere changes and crop metabolic evolution: The role of carbon materials

To investigate the effects of modified carbon-based materials on soil environmental remediation and crop physiological regulation, this research relied on rice pots with lead (Pb) and cadmium (Cd) composite contamination. Dolomite, montmorillonite, attapulgite and sepiolite modified biochar with different doses have been developed to explore the mechanisms on heavy metal passivation, nutrient improvement, microbial activation, and crop growth. The results indicated that the modified materials effectively reduced heavy metal bioavailability and accumulation in plant tissues through adsorption complexation. Specifically, under montmorillonite and sepiolite modified treatments, the Grains-Pb content significantly decreased by 29.23–30.31% and 27.49–30.58%, compared to the control group (CK). Meantime, carbon-based materials increased available nutrient levels, providing a biological substrate for soil microorganisms metabolism. The content of ammonium nitrogen (NH4+-N) and available phosphorus (AP) in different proportions of montmorillonite modified biochar increased by 10.99–13.98% and 55.76–77.86%, respectively, compared to CK. Furthermore, sepiolite modified biochar enhanced bacterial community diversity, significantly improving the tolerance and resistance of bacterial communities such as Proteobacteria and Acidobacteria to heavy metals. Meanwhile, carbon-based materials enhanced community stability and network complexity, improving microbial stress resistance to adverse environments. In summary, montmorillonite and sepiolite modified biochar regulated microbial community interaction mechanisms by mitigating the physiological toxicity of heavy metals. This process enhanced soil available nutrients and ecological function stability, which had significant implications for improving crop growth and quality.

Circadian de(regulation) in physiology: implications for disease and treatment.

Time plays a crucial role in the regulation of physiological processes. Without a temporal control system, animals would be unprepared for cyclic environmental changes, negatively impacting their survival. Experimental studies have demonstrated the essential role of the circadian system in the temporal coordination of physiological processes. Translating these findings to humans has been challenging. Increasing evidence suggests that modern lifestyle factors such as diet, sedentarism, light exposure, and social jet lag can stress the human circadian system, contributing to misalignment; i.e., loss of phase coherence across tissues. An increasing body of evidence supports the negative impact of circadian disruption on several human health parameters. This review aims to provide a comprehensive overview of how circadian disruption influences various physiological processes, its long-term health consequences, and its association with various diseases. To illustrate the relevant consequences of circadian disruption, we focused on describing the many physiological consequences faced by shift workers, a population known to experience high levels of circadian disruption. We also discuss the emerging field of circadian medicine, its founding principles, and its potential impact on human health.

Supplemental Material for Physiological Regulation Processes Differentiate the Experience of Ruptures Between Patient and Therapist

Supplemental Material for Physiological Regulation Processes Differentiate the Experience of Ruptures Between Patient and Therapist

Modulation of Carnitine Palmitoyl Transferase 1b Expression and Activity in Muscle Pathophysiology in Osteoarthritis and Osteoporosis

In the pathophysiology of osteoarthritis and osteoporosis, articular cartilage and bone represent the target tissues, respectively, but muscle is also involved. Since many changes in energy metabolism occur in muscle with aging, the aim of the present work was to investigate the involvement of carnitine palmitoyl transferase 1b (Cpt1b) in the muscle pathophysiology of the two diseases. Healthy subjects (CTR, n = 5), osteoarthritic (OA, n = 10), and osteoporotic (OP, n = 10) patients were enrolled. Gene expression analysis conducted on muscle and myoblasts showed up-regulation of CPT1B in OA patients; this result was confirmed by immunohistochemical and immunofluorescence analyses and enzyme activity assay, which showed increased Cpt1b activity in OA muscle. In addition, CPT1B expression resulted down-regulated in cultured OP myoblasts. Given the potential involvement of Cpt1b in the modulation of oxidative stress, we investigated ROS levels, which were found to be lower in OA myoblasts, and gene expression of nicotinamide adenine dinucleotide phosphate hydrogen oxidase 4 (Nox4), which resulted up-regulated in OA cells. Finally, the immunofluorescence of BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (Bnip3) showed a decreased expression in OP myoblasts, with respect to CTR and OA. Contextually, through an ultrastructural analysis conducted by Transmission Electron Microscopy (TEM), the presence of aberrant mitochondria was observed in OP muscle. This study highlights the potential role of Cpt1b in the regulation of muscle homeostasis in both osteoarthritis and osteoporosis, allowing for the expansion of the current knowledge of what are the molecular biological pathways involved in the regulation of muscle physiology in both diseases.

Green synthesized iron oxide nanoparticles as a potential regulator of callus growth, plant physiology, antioxidative and microbial contamination in Oryza sativa L.

In tissue culture, efficient nutrient availability and effective control of callus contamination are crucial for successful plantlet regeneration. This study was aimed to enhance callogenesis, callus regeneration, control callus contamination, and substitute iron (Fe) source with FeO-NPs in Murashige and Skoog (MS) media. Nanogreen iron oxide (FeO-NPs) were synthesized and well characterized with sizes ranging from 2 to 7.5 nm. FeO-NPs as a supplement in MS media at 15 ppm, significantly controlled callus contamination by (80%). Results indicated that FeCl3-based FeO-NPs induced fast callus induction (72%) and regeneration (43%), in contrast FeSO4-based FeO-NPs resulted in increased callus weight (516%), diameter (300%), number of shoots (200%), and roots (114%). Modified media with FeO-NPs as the Fe source induced fast callogenesis and regeneration compared to normal MS media. FeO-NPs, when applied foliar spray, increased Plant fresh biomass by 133% and spike weight by 350%. Plant height increased by 54% and 33%, the number of spikes by 50% and 265%, and Chlorophyll content by 51% and 34% in IRRI-6 and Kissan Basmati, respectively. Additionally, APX (Ascorbate peroxidase), SOD (Superoxide dismutase), POD (peroxidase), and CAT (catalase) increased in IRRI-6 by 27%, 29%, 283%, 62%, while in Kissan Basmati, APX increased by 70%, SOD decreased by 28%, and POD and CAT increased by 89% and 98%, respectively. Finally, FeO-NPs effectively substituted Fe source in MS media, shorten the plant life cycle, and increase chlorophyll content as well as APX, SOD, POD, and CAT activities. This protocol is applicable for tissue culture in other cereal crops as well.

Situating homeostasis in organisms: maintaining organization through time.

Since it was inspired by Bernard and developed and named by Cannon, the concept of homeostasis has been invoked by many as the central theoretical framework for physiology. It has also been the target of numerous criticisms that have elicited the introduction of a plethora of alternative concepts. We argue that many of the criticisms actually target the more restrictive account of homeostasis advanced by the cyberneticists. What was crucial to Bernard and Cannon was a focus on the maintenance of the organism as the goal of physiological regulation. We analyse how Bernard's and Cannon's broad conception of what was required to maintain the organism was narrowed to negative feedback, characterized in terms of setpoints, by the cyberneticists and demonstrate how many of the alternative concepts challenge the role of setpoints - treating them as variable in light of circumstances or in anticipation of future circumstances, or as dispensable altogether. To support our analysis, we draw on the experimental and theoretical work on thermoregulation, a phenomenon that has been considered as a paradigmatic example of homeostasis and has been a common focus of those advancing alternative concepts. To integrate the insights advanced by the original proponents of homeostasis and the theorists proposing replacement notions we advance a framework in which regulation is viewed from the perspective of maintaining the organism.

Using a virtual reality game to train biofeedback-based regulation under stress conditions.

Physiological regulation strategies can be effective in reducing anxiety. However, while these strategies are often learned and practised under low-stress conditions, they are more likely to be required under conditions of high stress. We created virtual reality (VR) biofeedback games to both teach participants a breathing technique and then practise that technique under stress. We present two studies: the first provides a proof of concept, demonstrating that participants can apply the breathing technique during stress, with a significant lowering of both respiration rate and increase in heart rate variability (HRV) under stress (p < .001). The second study explicitly evaluated the effectiveness of training by comparing trained and untrained groups. Training was associated with a significantly greater HRV (p = .008) under stress. In within-group comparisons of HRV during stress compared to a baseline stressor presented before training, the trained group showed a significantly greater increase compared to untrained controls (p = .025). Our results show the feasibility and potential effectiveness of VR-based games for biofeedback training under experimentally applied stress. This may offer the opportunity for clinical techniques to more closely reflect the circumstances under which those techniques will be required.