Search Results (423)

This study aimed to investigate the effects of different light treatments on the growth, antioxidant activity, and metabolite profiles of Samsoniella hepiali. Mycelial biomass, bioactive components, antioxidant capacity, and metabolomic profiles were analyzed under dark, continuous light, and 12 h light/12 h dark cycle conditions. The results showed that the 12 h light/dark cycle significantly reduced dry mycelial weight compared to the dark and continuous light groups (p < 0.001), while no significant difference in biomass was observed between the latter two. Polysaccharide (Pol) content did not differ significantly among the three groups. In terms of antioxidant activity, the continuous light group exhibited the highest protein (Prot) content, total phenolic (TP) content, DPPH radical scavenging activity, and ferric reducing antioxidant power (FRAP) as well as the lowest superoxide anion (·O₂⁻) content. The dark group showed the highest activities of superoxide dismutase (SOD) and catalase (CAT). Correlation analysis revealed that total phenolic (TP) content was significantly positively correlated with 2,2-Diphenyl-1-picrylhydrazy (DPPH) and FRAP (p < 0.01), and significantly negatively correlated with superoxide anion content (p < 0.05). Non-targeted metabolomics identified 3643 metabolites, primarily amino acids and derivatives, organic acids, and glycerophospholipids. KEGG enrichment analysis indicated significant accumulation of differential metabolites such as linoleic acid, tyrosine, and phosphatidylcholine across comparison groups. These findings provide insights into the regulatory role of light exposure on the antioxidant capacity of S. hepiali and support its further development in fermented mycelial products. Full article

The pineal gland is a key component of the avian circadian system, responsible for melatonin (MLT) secretion that reflects and regulates daily rhythmicity. While the post-hatching turkey is known for its highly sensitive and efficient pineal system, the functional development of this gland during embryogenesis has not been described. To determine the measurable onset and regulation of MLT secretion, pineal glands from turkey embryos aged 22, 24, and 26 days (ED 22–26) were incubated in a superfusion culture under various light conditions and with or without norepinephrine (NE). MLT concentrations in the medium were measured by radioimmunoassay. Under the experimental conditions, MLT secretion was first reliably measurable at ED 22 and increased thereafter toward hatching. Under a 12L:12D cycle, pinealocytes exhibited a stable circadian rhythm with a fourfold amplitude between night and day. The glands adapted to a reversed light–dark cycle and responded strongly to a 3 h nocturnal light pulse with a 30% decrease in MLT levels. Rhythmic MLT secretion persisted under constant light or darkness, indicating an active endogenous oscillator. NE markedly suppressed MLT secretion in all embryos, confirming the early development of adrenergic regulation. Thus, by ED 22 the embryonic turkey pineal exhibits photosensitivity, endogenous rhythmicity, and NE responsiveness, although secretion at earlier stages cannot be excluded due to detection limits. These results fill a gap in understanding avian pineal ontogeny and establish the turkey embryo as a good model for studying the early development of circadian regulation in birds. Full article

Daily rhythms define physical, mental, and behavioral changes that the body experiences over a 24 h cycle. The light–dark cycle plays a crucial role in regulating daily rhythms, but other factors such as food intake, stress, and physical activity also affect them. Cortisol secretion exhibits one of the largest endocrine amplitudes, with an early morning peak and late-evening nadir driven by the suprachiasmatic nucleus and hypothalamus–pituitary–adrenal axis, representing the most robust endocrine output of the circadian system. Beyond photic cues, feeding is a potent non-photic zeitgeber that entrains peripheral oscillators and dynamically shapes cortisol secretion. This narrative review aims to explore the effect of feeding in modulating cortisol secretion. The misalignment of the daily cortisol-secretion rhythm, with blunted cortisol awakening response and elevated evening levels, leads to metabolic syndrome, psychiatric disorders, shift work, and jet lag. In endogenous hypercortisolism, the loss of rhythmicity rather than absolute exposure best predicts risk. Therefore, we discuss practical nutritional tools as opportunities to partially restore rhythmic hypothalamus–pituitary–adrenal axis physiology. Full article

Background: White adipose tissue (WAT) exhibits diurnal oscillations regulated by clock genes, which autonomously control its functionality. These rhythms are modulated by the central clock and external factors, such as light exposure and diet. Flavanols, phenolic compounds known for their beneficial metabolic effects, have been shown to modulate the expression of clock genes. This study explored the impact of flavanols on clock gene expression in WAT explants from lean and obese rats under changes in light/dark cycles. Methods: WAT explants were obtained from 24 Fischer rats fed a standard diet (STD) or cafeteria diet (CAF) for seven weeks. During the final week, rats were changed to short (6 h of light, L6) or long (18 h of light, L18) photoperiods. CAF-fed rats were also administered a grape seed (poly)phenol-rich extract (GSPE) (25 mg/kg) or vehicle (VH). After sacrifice, WAT explants were collected every 6 h starting at 8 a.m. the following day (CT0, CT6, CT12, CT18, and CT24). Results: The results showed that under L18 conditions, STD-fed rats displayed oscillations in Bmal1, Cry1, Per1, and Rev-erbα clock gene expression, whereas many of these rhythms were disrupted under L6 conditions. Moreover, the administration of the CAF diet also resulted in the loss of clock gene circadian oscillations in the WAT explants. GSPE administration restored the oscillation of these clock genes under L18 and L6 conditions. Conclusions: These findings highlight the potential zeitgeber role of flavanols in modulating WAT peripheral clocks and their capacity to improve metabolic and circadian regulation under conditions of diet- and photoperiod-induced disruption. Full article

The escalating threat of cyanobacterial blooms necessitates a deeper understanding of the environmental factors regulating their toxicity. While light intensity effects are well-documented, it remains unclear whether photoperiod regulates microcystin (MC) production. This study investigates the effects of five light–dark (LD) cycles on the growth and MC-LR production of two Microcystis strains in batch culture under a light intensity of 25 μmol m⁻² s⁻¹. Longer photoperiods enhanced early growth, although long-term biomass accumulation proved strain-dependent. Regarding toxin production, cellular MC-LR (total toxin per cell) during the initial 9-day phase was analyzed using a mixed-effects model. The analysis revealed significant main effects of photoperiod and cell density, supporting both direct and growth-mediated indirect effects of photoperiod. Moreover, a significant strain × photoperiod × day interaction (p < 0.001) was observed, indicating additional strain-specific and time-dependent regulation. Conversely, a general linear model of the strictly intracellular MC-LR at the 27-day endpoint showed significant independent effects of photoperiod and cell density, with no interaction. The photoperiod effect strengthened after controlling for cell density. These findings reveal a phase-dependent regulation of toxicity, suggesting that risk assessment based solely on biomass is inadequate. Sustainable bloom management should therefore incorporate photoperiod dynamics and adopt phase-specific strategies. Full article

Purpose: This study evaluates a novel, non-invasive method using a virtual reality (VR) headset with integrated eye trackers to assess retinal function by measuring the recovery of the pupillary response after light adaptation in patients with age-related macular degeneration (AMD). Methods: In this pilot study, fourteen patients with clinically confirmed AMD and 14 age-matched healthy controls were exposed to alternating bright and dark stimuli using a VR headset. The dark stimulus duration increased incrementally by 100 milliseconds per trial, repeated over 50 cycles. The pupillary response to the re-onset of brightness was recorded. Data were analyzed using a linear mixed-effects model to compare recovery patterns between groups and a convolutional neural network to evaluate diagnostic accuracy. Results: The pupillary response amplitude increased with longer dark stimuli, i.e., the longer the eye was exposed to darkness the bigger was the subsequent pupillary amplitude. This pupillary recovery was significantly slowed by age and by the presence of macular degeneration. Test diagnostic accuracy for AMD was approximately 92%, with a sensitivity of 90% and a specificity of 70%. Conclusions: This proof-of-concept study demonstrates that consumer-grade VR headsets with integrated eye tracking can detect retinal dysfunction associated with AMD. The method offers a fast, accessible, and potentially scalable approach for retinal disease screening and monitoring. Further optimization and validation in larger cohorts are needed to confirm its clinical utility. Full article

Liver rhythm has a significant effect on lipid metabolism and immune function in chickens. However, reports on its underlying mechanisms and key genes are relatively scarce. We collected liver samples at seven time points during one light/dark cycle and investigated the candidate genes and pathways related to hepatic rhythm through transcriptomic sequencing. Trend analysis revealed that the expression of genes in Profile 5 exhibited rhythmic fluctuations, and these genes (e.g., FAM21C, SRSF4, and TLR2A) were enriched in immune function and biological rhythm. The genes (e.g., MSMO1, ELOVL2, and HMGCR) in Profile 2 that were related to lipid metabolism also exhibited a rhythmic trend. A total of 845 differentially expressed genes (e.g., MSMO1 and FAM21C) were detected between light/dark conditions. Lipid metabolism and immune functions showed the most changes between the two conditions. Immune-related processes (e.g., autophagy) were more active in the light phase, while in the dark phase, lipid metabolism (e.g., sterol biosynthesis) was more active. Weighted gene coexpression network analysis revealed that the tan (including C1QA, TLR2A, and others) and cyan (including ELOVL2, IARS1, and others) modules were strongly associated with the hepatic circadian rhythm. Cosinor analysis revealed that 9 lipid-related genes (e.g., MSMO1, HMGCR1, and ELOVL2) and 11 immune-related genes (e.g., FAM21C, TLR4, and TLR2A) exhibited significant rhythmic expression. These findings revealed rhythmic changes in hepatic immune and lipid metabolism, providing important insights into the regulation of disease resistance and lipid deposition in chickens. Full article

Background/Objectives: Seasonal reproduction in mammals is primarily regulated by the hypothalamic–pituitary–ovarian (HPO) axis, yet its molecular mechanisms in subterranean rodents living in light-restricted environments remain poorly understood. This study aimed to characterize the transcriptional regulation of the HPO axis during seasonal estrus in the Manchurian zokor (Myospalax psilurus, M. psilurus), a fossorial rodent exhibiting distinct breeding cycles despite perpetual darkness. Methods: Hypothalamic, pituitary, and ovarian tissues were collected from female zokors during estrus and anestrus (n = 5 per group). RNA sequencing was performed, followed by de novo transcriptome assembly and bioinformatic analyses. Differentially expressed genes (DEGs) were identified using edgeR, and functional enrichment was assessed via GO and KEGG analyses. Key DEGs were validated by RT-qPCR. Results: A total of 513, 292, and 138 DEGs were identified in the hypothalamus, pituitary, and ovary, respectively. GO analysis highlighted enrichment in G-protein-coupled receptor signaling, oxidation–reduction processes, and calcium ion binding. KEGG pathway analysis revealed significant enrichment of the neuroactive ligand–receptor interaction pathway across all three tissues. Key candidate genes included Trh and Mc3r in the hypothalamus, Pitx2 and NR4A2 in the pituitary, and PTGER2 and Sphk1 in the ovary. Conclusions: This study provides the first comprehensive transcriptomic profile of the HPO axis in Manchurian zokors during seasonal estrus. The neuroactive ligand–receptor interaction pathway appears central to reproductive regulation, and several tissue-specific genes were identified as potential regulators of seasonal breeding. These findings enhance our understanding of reproductive adaptation in subterranean mammals and offer a foundation for further functional studies. Full article

Celery (Apium graveolens L.) is a widely cultivated leafy vegetable of significant agronomic and nutritional importance. Owing to its high nutritional value, global demand for celery has steadily increased. However, under natural cultivation conditions, uncontrolled light exposure often prolongs the seedling stage and impairs celery growth quality. Improving the nutritional quality of celery through artificial regulation of the light environment has therefore become an important research focus. This work aimed to elucidate the impact of varying light–dark cycles on the growth characteristics and nutritional attributes of celery. Six light–dark cycle treatments (4 h/2 h, 8 h/4 h, 16 h/8 h, 24 h/12 h, 32 h/16 h, and 40 h/20 h) were applied, using ‘Oster Ziyu Xiangqin’ as the plant material under a constant light intensity of 400 μmol·m⁻²·s⁻¹. The results revealed that the 24 h/12 h light–dark treatment significantly enhanced plant height, total fresh weight, and root vigor and showed superior performance in photosynthetic and chlorophyll fluorescence parameters. The 32 h/16 h treatment significantly enhanced the accumulation of soluble sugars, proteins, total phenolic compounds, and flavonoids, as well as the activities of antioxidant enzymes, while reducing nitrate-nitrogen levels. In conclusion, the 24 h/12 h light–dark cycle was most conducive to the growth and photosynthetic performance of celery, whereas the 32 h/16 h treatment optimally enhanced its nutritional quality and antioxidant capacity. Full article

This study was designed to identify factors, including estrous cycle length, affecting the incidence of double ovulations in dairy cows. The study population comprised 748 primiparous cows undergoing spontaneous estrous cycles that had undergone their first postpartum artificial insemination following the second observed estrus. A subset of 341 cows with inter-estrus intervals (IEIs) of 18 to 30 days were selected to investigate the impacts of IEI, which was classified as normal (18–23 days) or lengthened (24–30 days). The odds ratio (OR) for double ovulations was 0.82 (p < 0.0001) for each unit increase in genomic prediction values for twin pregnancies, 2.3 (p < 0.0001) for cows inseminated during the negative photoperiod, compared to cows inseminated during the positive photoperiod, and 2.8 (p = 0.02) for cows with lengthened cycles, compared to cows with normal cycles. The OR for lengthened IEIs was 0.91 (p = 0.001) for each unit increase in genomic prediction value, and 4.4 (p < 0.0001) for cows inseminated during the negative photoperiod. In conclusion, lengthened estrous cycles were associated with double ovulations, genomic prediction values were able to identify the risk of lengthened cycles, and the negative photoperiod was found to favor both lengthened cycles and double ovulations. Full article

Generation of state-of-the-art highly productive cabbage genotypes (Brassica oleracea convar. capitata (L.) Alef.) with improved agronomic traits is attainable using modern biotechnological approaches. However, capitata cabbage is relatively recalcitrant to de novo shoot organogenesis from callus tissue, especially with loss of somatic cell totipotency during genetic transformation. An effective and rapid protocol for in vitro indirect shoot organogenesis from hypocotyl and cotyledon explants derived from 6-day-old aseptic donor seedlings of Russian cabbage genotypes (the DH line as well as cvs. Podarok and Parus) has been developed. In order to obtain standardized donor explants, aseptic cabbage seeds were germinated under dim light conditions (30–40 µmol m⁻² s⁻¹) with a 16 h light/8 h dark photoperiod. Multiple indirect shoot organogenesis (1.47–4.93 shoots per explant) from both cotyledonary leaves and hypocotyl segments with a frequency of 55.2–89.1% was achieved through 45 days of culture on the 0.7% agar-solidified (w/v) Murashige and Skoog (MS) basal medium containing 2 mg/L 6-benzylaminopurine (6-BAP), 0.02 mg/L 1-naphthalene acetic acid (NAA), and 5 mg/L AgNO₃. The regenerants were successfully rooted on an MS basal medium (69.2%) without plant growth regulators (PGRs), as well as supplemented with 0.5 mg/L NAA (86.8%). Subsequently, in vitro rooted cabbage plantlets were adapted to soil conditions with an efficiency of 85%. This rapid protocol, allowing for the performance of a full cycle from in vitro seed germination to growing adapted plantlets under ex vitro conditions over 95 days, can be successfully applied to induce an indirect shoot formation in various cabbage genotypes, and it is recommended to produce transgenic plants with improved quality traits and productivity. Full article

Clavibacter michiganensis causes significant crop losses in tomatoes, and the disease may be transferred by plant seeds. This study evaluates the efficacy of Photodynamic Inactivation (PDI) with a water-soluble hypericin derivative, developed as a complex with polyvinylpyrrolidone (high hypericin-loaded PVP, HHL-PVP), as a decontamination strategy for tomato seeds. HHL-PVP was chosen for its overall stability, as the complex remains stable in solution for over 950 days, maintains its absorption capacity after illumination with 200 J·cm⁻², and produces reactive oxygen species (ROS) even at concentrations as low as 1 µM. PDI against C. michiganensis with 5 μM HHL-PVP, 10 min drug to light interval (DLI), and illumination with red light (600–700 nm, 100 J·cm⁻²) exceeded the antimicrobial effect of a 99.9% reduction in liquid culture. Increasing the DLI to 24 h did not alter the photokilling effect. A 14 h light/10 h dark cycle in white light (118 J·cm⁻²) with 0.3 µM HHL-PVP inhibited the growth of C. michiganensis by more than 6 log₁₀ steps, indicating that HHL-PVP has a stable and long-lasting photokilling effect. The combination of HHL-PVP with potassium iodide (KI, 100 mM) completely eradicated C. michiganensis in liquid culture with red and white light, indicating KI’s role in enhancing phototoxicity. Tomato seed photodynamic decontamination using 1.0 µM HHL-PVP activated by 200 J·cm⁻² white light inactivated >5 log₁₀ of C. michiganensis, without diminishing sprouting. An addition of 100 mM KI increased the percentage of sprouted seedlings and inactivated 100% of bacteria. These results demonstrate that HHL-PVP-mediated PDI combined with KI could be highly effective as a preventative strategy in tomato protection against C. michiganensis. Full article

Light plays an essential role in regulating the growth, development, and metabolic activities of the edible mushroom Pleurotus ostreatus. In this research, the influence of white, blue, green, yellow, and red light, and darkness, on the global protein expression of P. ostreatus LGAM 1123 grown in submerged culture was explored. The growth of the fungus was not inhibited by light in any of the conditions tested compared with the dark. However, the mycelial protein content was reduced by 10% under blue and white light. Proteomic analysis revealed distinct proteomes for each light wavelength, with red and blue light presenting the most distinctive proteome profiles. (Data are available via ProteomeXchange with identifier PXD065402.) Blue light activates pathways such as the citrate cycle (TCA cycle), glycolysis/gluconeogenesis, and amino acid biosynthesis, while red light stimulates mRNA-related pathways. GC-MS analysis of the biomass revealed differences in the amino acids, sugars, and lipids produced. The distinct regulation of proteins and bioactive compounds under different light wavelengths suggests that specific wavelengths can direct the metabolism of P. ostreatus into biochemical pathways. These strategies could be beneficial for the food industry because particular nutrients can be increased during the fermentation of edible fungi without the need for genetic engineering of the strain. Full article

Background: It has recently been proposed that the retina plays an important modulatory role in the control of motor function that is usually attributed exclusively to the function of the nigro-striatal dopamine (NSD) system. Indeed, it has been proposed further that Parkinson’s disease (PD) begins in and progresses from the retina and may be effectively treated from there. While previous intraocular work has employed intravitreal (IVIT) administration of toxins to induce experimental PD, the first study series reported here examines the effect of IVIT haloperidol on motor performance while the second study examines the effect of IVIT haloperidol on the unilateral rotation model of PD, both in a circadian context. Methods: Motor tests included open field performance and the latency to perform three motor tests after the IVIT injection of haloperidol with and without amphetamine pretreatment. In a second study, IVIT injections of the melatonin antagonist ML-23 or L-dopa were made after unilateral lesions of the NSD in rats that were placed in a rotometer examining spontaneous ipsilateral and contralateral turning. Results: IVIT haloperidol produced robust changes in several motor parameters during the light and dark phase of the LD cycle which were enhanced by amphetamine pretreatment. In the second study, while IVIT L-dopa had only a minor effect on spontaneous rotation during the light phase, IVIT haloperidol produced a robust effect upon ipsilateral turning. The reduction in spontaneous ipsilateral turning was seen after IVIT injections into the eye ipsilateral or contralateral to the hemisphere in which NSD destruction occurred. Reduced turning was seen during both the light and dark phases of the L/D cycle. Conclusions: These results illustrate that IVIT injections of DA and melatonin receptor antagonists can differentially alter motor function via the retina. This suggests that the retina may be a treatment target not only for PD but also for other DA- and melatonin-mediated disorders such as drug addiction, psychosis and schizophrenia. Full article

Background/Objectives: Glutamatergic neurotransmission is essential for the normal functioning of the retina. Photoreceptor to bipolar and bipolar to ganglion cell signaling is mediated by L-glutamate, which is stored in and released from vesicular glutamate transporter 1 (VGLUT1) containing synaptic vesicles. VGLUT1 is expressed postnatally, P2 onwards, and is required for the glutamatergic retinal wave observed between P10 and P12 in the developing mouse retina. P9–P13 postnatal age is critical for retinal development as VGLUT1 expressing ribbon synapses activate in the outer and inner plexiform layers, and rod/cone mediated visual signaling commences in that period. Although it has been hypothesized that glutamatergic extrinsic signaling drives cell cycle exit and initiates cellular differentiation in the developing retina, it is not clear whether intracellular, synaptic, or extrasynaptic vesicular glutamate release contributes to this process. Recent studies have attempted to decipher VGLUT’s role in retinal development. Here, we investigate the potential effect of genetic loss of VGLUT1 on early postnatal histogenesis and development of retinal neural circuitry. Methods: We employed immunohistochemistry and electrophysiology to ascertain the density of glutamatergic, cholinergic, and dopaminergic cells, spontaneous retinal activity, and light responses in VGLUT1 null retina, and contrasted them with wildtype (WT) and melanopsin null retina. Results: We have demonstrated here that VGLUT1 null retina shows signs of age dependent retinal degeneration, similar to other transgenic mice models with dysfunctional photoreceptor to bipolar cell synapses. The loss of VGLUT1 specifically alters glutamatergic cell density and morphological maturation of retinal ganglion cells. Moreover, VGLUT2 expression is lost in the majority of VGLUT2 cones in the absence of VGLUT1 coexpression, except when VGLUT2 coexpresses transiently with VGLUT3 in these cones, or when VGLUT1 null mice are dark reared. Conclusions: We present the first evidence that synaptic or extrasynaptic postnatal glutamate release from VGLUT1 containing vesicles impacts histogenesis of glutamatergic cells, pruning of retinal ganglion cell dendrites and VGLUT2 expression in cones. Full article