Light Avoidance Research Articles

Do seabirds dream of artificial lights? Understanding light preferences of Procellariiformes.

Seabirds, and particularly fledglings of burrow-nesting species, are greatly impacted by light pollution. During their inaugural flights from colony to sea, fledglings become grounded after encountering artificial light. Such groundings, or fallout events, affect many fledglings each year, causing mass mortality events. To mitigate this light-induced mortality, rescue programmes have been implemented for decades at many locations worldwide. Despite the notoriety of fallouts and their conservation implications, the contributing behavioural and biological factors remain mostly unknown. How the mechanisms of light attraction and light avoidance interact and how they manifest in different groups (e.g. age, personality, populations) or light pollution levels remain open questions. We tested behavioural choices of Cory's shearwater Calonectris borealis fledglings, rescued after being grounded in urban areas, and choices of breeding adults for contrasting light sources. Fledglings and adults were exposed to one of three treatments in an experimental Y-maze set-up: white light versus no light, blue versus red light, and a control with no light on each arm of the Y-maze. Both age groups clearly chose the no-light arms and the red light arm. This choice for longer wavelengths and darker environments, along with slower responses by fledglings, suggests that close range artificial light causes disorientation in seabirds. Our study helps to clarify the behavioural components of fallouts and provides further evidence on the disruptive effects of nocturnal artificial light on sensitive species like Procellariiformes.

Analysis of changes in nutritional compounds of dried yellow chili after different processing treatments

Dried yellow chili is highly appreciated by consumers due to its excellent quality and flavor. The quality of products is determined by the drying and storage methods. In this study, dried yellow chilis were processed by natural air drying and hot air drying methods and then stored under three conditions: ambient temperature, ambient temperature with light avoidance, and at 10 °C with light avoidance for 12 months. The changes in the bioactive compounds during this period were analyzed attempting to reveal correlations between the different treatments and these compounds, with the aim of providing references for maintaining the bioactive compounds of pepper products. The results showed that samples treated with hot air had higher levels of fatty acids, resulting in a more pronounced flavor. During storage, samples stored at 10 °C with light avoidance were more effective in preserving soluble solids, total protein content, total phenols, capsaicinoids and most fatty acids.

Modeling Fragile X Syndrome: Characterizing Fmr1 Gene Knockout Mice across Genotype, Behavior, and Morphology

ABSTRACT Objective: Fragile X syndrome (FXS) is a hereditary condition resulting from dynamic mutations in the Fmr1 gene, leading to reduced or absent fragile X mental retardation protein (FMRP). Although molecular genetic diagnostics for FXS have advanced, there is currently a lack of effective clinical treatment. Hence, identifying a suitable FXS animal model is crucial for FXS therapeutic studies. This study primarily aims to evaluate whether Fmr1 mice display aberrant behaviors similar to those observed in human FXS patients, aiming to validate their feasibility as a model for FXS. Research Design and Methods: Polymerase chain reaction and immunoblotting were employed to genotype Fmr1 knockout (KO) mice and wild-type (WT) mice. Using hematoxylin and eosin staining and Golgi staining, testicular and dendritic spine morphology in both animal groups was observed. The animals were subjected to audiogenic seizure (AGS) observation, evaluating their learning and memory levels using the water maze and light avoidance methods, while their exploratory behavior capacity was assessed using the open-field and autonomous activity experiments. Anxiety behavior was evaluated using the elevated plus maze. Results: WT mice produced a 500 bp DNA fragment, while KO mice yielded an 800 bp fragment. KO mice exhibited a lack of FMRP expression, notably increased dendritic spine length and density, and presented with macroorchidism. KO mice showed increased susceptibility to AGS. In the Morris water maze experiment, KO mice displayed significantly increased escape latency and platform crossings. The spatial search experiment revealed that KO mice spent significantly less time in the target quadrant compared to WT mice. The light-avoidance and platform experiments indicated a significant reduction in latency for KO mice but an increase in errors. In the open-field experiment, KO mice spent significantly more time and made more entries into the central zone compared to WT mice. KO mice exhibited increased total travel distance and speed. The elevated plus maze experiment showed that KO mice spent significantly more time, made more entries, and traveled further in the open area compared to WT mice. The autonomous activity experiment revealed that KO mice had significantly more activity counts than WT mice but fewer standing counts. Conclusions: Findings from genotype, protein expression spectrum, morphology, and behavioral results suggest that Fmr1 gene KO mice demonstrate phenotypes similar to those observed in human FXS, making them a potential model for future FXS research. These phenotypes are associated with the absence of FMRP expression.

Light perception and related alternation of physiological performance in spotted knifejaw Oplegnathus punctatus

Light is one of the main environmental factors that affects the behavior and physiology of fish. In the present study, the behavioral responses, retinal histology, hematological parameters (white blood cell [WBC], red blood cell [RBC], hemoglobin [Hb] hematocrit [Hct]), hepatic antioxidant enzyme (superoxide dismutase [SOD], catalase [CAT], and glutathione peroxidase [GSH-Px]) activity, aspartate-aminotransferase (AST) and alanine-aminotransferase (ALT) activities, malondialdehyde (MDA) content, histological alterations, apoptosis, and stress-related gene expression (hsp70, hsp90a, hsp90b) of spotted knifejaw were investigated under different light colors. The results showed that the residence time of spotted knifejaw plants significantly decreased under red and blue light stimuli but significantly increased under green light. Moreover, a positive and negative phototaxis of the spotted knifejaw under green and red lights was observed. However, retinal structure (relative thickness, cell number, and size) remained unchanged after red and green light treatment for 12 h. WBC and RBC numbers, Hb and Hct contents, hepatic SOD, CAT, GSH-Px, ALT and AST activities, and MDA levels were significantly increased after red and green light treatment for 12 h. Moreover, red and green light treatment caused hepatocyte vacuolization and nuclear migration and significantly increased the percentage of apoptotic cells. Hepatic hsp70, hsp90a, and hsp90b mRNA levels were significantly upregulated under red and green stimuli. Furthermore, the values of the above parameters under red light treatment were significantly greater than those under green light treatment. The aforementioned parameters nearly recovered to normal levels after the fish returned to normal light for 12 h. In conclusion, in spotted knifejaw, green light promoted attraction and red light avoidance, while red light could induce a more sensitive physiological response than green light. These findings expand the current knowledge on light perception and aid in the management of spotted knifejaw in captivity.

Personal light exposure patterns and incidence of type 2 diabetes: analysis of 13 million hours of light sensor data and 670,000 person-years of prospective observation

Light at night disrupts circadian rhythms, and circadian disruption is a risk factor for type 2 diabetes. Whether personal light exposure predicts diabetes risk has not been demonstrated in a large prospective cohort. We therefore assessed whether personal light exposure patterns predicted risk of incident type 2 diabetes in UK Biobank participants, using ∼13 million hours of light sensor data. Participants (N=84,790, age (M ± SD)=62.3±7.9 years, 58% female) wore light sensors for one week, recording day and night light exposure. Circadian amplitude and phase were modeled from weekly light data. Incident type 2 diabetes was recorded (1997 cases; 7.9±1.2 years follow-up; excluding diabetes cases prior to light-tracking). Risk of incident type 2 diabetes was assessed as a function of day and night light, circadian phase, and circadian amplitude, adjusting for age, sex, ethnicity, socioeconomic and lifestyle factors, and polygenic risk. Compared to people with dark nights (0-50th percentiles), diabetes risk was incrementally higher across brighter night light exposure percentiles (50-70th: multivariable-adjusted HR=1.29 [1.14-1.46]; 70-90th: 1.39 [1.24-1.57]; and 90-100th: 1.53 [1.32-1.77]). Diabetes risk was higher in people with lower modeled circadian amplitude (aHR=1.07 [1.03-1.10] per SD), and with early or late circadian phase (aHR range: 1.06-1.26). Nightlight and polygenic risk independently predicted higher diabetes risk. The difference in diabetes risk between people with bright and dark nights was similar to the difference between people with low and moderate genetic risk. Type 2 diabetes risk was higher in people exposed to brighter night light, and in people exposed to light patterns that may disrupt circadian rhythms. Avoidance of light at night could be a simple and cost-effective recommendation that mitigates risk of diabetes, even in those with high genetic risk. Australian Government Research Training Program.

Meningeal lymphatic CGRP signaling governs pain via cerebrospinal fluid efflux and neuroinflammation in migraine models.

Recently developed antimigraine therapeutics targeting calcitonin gene-related peptide (CGRP) signaling are effective, though their sites of activity remain elusive. Notably, the lymphatic vasculature is responsive to CGRP signaling, but whether meningeal lymphatic vessels (MLVs) contribute to migraine pathophysiology is unknown. Mice with lymphatic vasculature deficient in the CGRP receptor (CalcrliLEC mice) treated with nitroglycerin-mediated (NTG-mediated) chronic migraine exhibit reduced pain and light avoidance compared with NTG-treated littermate controls. Gene expression profiles of lymphatic endothelial cells (LECs) isolated from the meninges of Rpl22HA/+;Lyve1Cre RiboTag mice treated with NTG revealed increased MLV-immune interactions compared with cells from untreated mice. Interestingly, the relative abundance of mucosal vascular addressin cell adhesion molecule 1-interacting (MAdCAM1-interacting) CD4+ T cells was increased in the deep cervical lymph nodes of NTG-treated control mice but not in NTG-treated CalcrliLEC mice. Treatment of cultured hLECs with CGRP peptide in vitro induced vascular endothelial-cadherin (VE-cadherin) rearrangement and reduced functional permeability. Likewise, intra cisterna magna injection of CGRP caused rearrangement of VE-cadherin, decreased MLV uptake of cerebrospinal fluid (CSF), and impaired CSF drainage in control mice but not in CalcrliLEC mice. Collectively, these findings reveal a previously unrecognized role for lymphatics in chronic migraine, whereby CGRP signaling primes MLV-immune interactions and reduces CSF efflux.

Larval swimming in the sea anemone Nematostella vectensis is sensitive to a broad light spectrum and exhibits a wavelength-dependent behavioral switch.

In nearly all animals, light-sensing mediated by opsin visual pigments is important for survival and reproduction. Eyeless light-sensing systems, though vital for many animals, have received relatively less attention than forms with charismatic or complex eyes. Despite no single light-sensing organ, the sea anemone Nematostella vectensis has 29 opsin genes and multiple light-mediated behaviors throughout development and reproduction, suggesting a deceptively complex light-sensing system. To characterize one aspect of this light-sensing system, we analyzed larval swimming behavior at high wavelength resolution across the ultraviolet and visual spectrum. N. vectensis larvae respond to light at least from 315 to 650 nm, which is a broad sensitivity range even compared to many animals with complex eyes. Planktonic swimming is induced by ultraviolet (UV) and violet wavelengths until 420 nm. Between 420 and 430 nm a behavioral switch occurs where at wavelengths longer than 430 nm, larvae respond to light by swimming down. Swimming down toward the substrate is distinct from light avoidance, as animals do not exhibit positive or negative phototaxis at any wavelength tested. At wavelengths longer than 575 nm, animals in the water column take increasingly longer to respond and this behavior is more variable until 650 nm where larval response is no different from the dark, suggesting these longer wavelengths lie outside of their sensitivity range. Larval swimming is the only motile stage in the life history of N. vectensis, and increased planktonic swimming could lead to greater dispersal range in potentially damaging shallow environments with short-wavelength light exposure. Longer wavelength environments may indicate more suitable substrates for metamorphosis into the polyp stage, where the individual will remain for the rest of its life. Future work will test whether this robust behavior is mediated by multiple opsins.

Physiological specialization of the brain in bumble bee castes: Roles of dopamine in mating-related behaviors in female bumble bees.

We aimed to investigate the roles of dopamine in regulating caste-specific behaviors in bumble bees and mating-related behaviors in bumble bee gynes. We examined caste differences in behaviors, biogenic amine levels, and expression levels of genes encoding dopamine receptors in the brains of bumble bees, and analyzed the effects of dopamine-related drugs on bumble bee behavior. Locomotor and flight activities were significantly higher in 8-day-old gynes and light avoidance was significantly lower in 4-8-day-old gynes than in same-aged workers. Brain levels of dopamine and octopamine were significantly higher in 8-day-old gynes than in same-aged workers, but tyramine and serotonin levels did not differ between the castes. Relative expression levels of the dopamine receptor gene BigDop1 were significantly lower in 8-day-old gynes than in same-aged workers, but expression levels of other dopamine receptor genes did not differ between castes. Dopamine significantly enhanced locomotor and flight activities in 7-9-day-old workers, whereas the dopamine receptor antagonist flupentixol inhibited flight activity and mating acceptance in same-aged gynes. These results suggest that dopamine plays important roles in gyne-specific behavior in bumble bees and has a common dopaminergic function in female eusocial bees.

Trade-Offs between Avoidance of Noxious Electric Shock and Avoidance of Bright Light in Shore Crabs Are Consistent with Predictions of Pain.

The suggestion that decapod crustaceans might experience pain has been dismissed by some authors who claim decapods only respond to noxious stimuli by nociceptive reflexes. Because reflexes do not require complex neuronal processing, but pain does, demonstrating reflex responses to noxious stimuli would not support the case for pain. Here, we report an experiment in which shore crabs are repeatedly placed in a light area (20 trials), but the animals can avoid the light by moving to a dark shelter. However, some crabs received an electric shock of 6 or 12 volts each time they entered the shelter. Those receiving either level of shock swiftly reduced their use of shelters and remained in the light. However, the magnitude of shelter avoidance was influenced by the brightness of the arena and the intensity of the shock. Shelter use was subsequently reduced to a greater extent if the shock level was high and the light intensity low. That is, crabs traded their avoidance of shock for their avoidance of bright light. Further, these animals showed avoidance learning and demonstrated activities suggesting anxiety, such as contact with the tank wall in the light area and increased latency to enter shelters when making the decision to enter the shelter if they had received shock in earlier trials. These results fulfil three key behavioural criteria for pain and, thus, are consistent with the idea that decapods can experience pain.

Study of the influence of warehousing conditions on the aging durability of bamboo

Bamboo photoaging refers to the chemical and physical changes in the surface after sunlight during outdoor/indoor use, such as texture roughness, polymer molecular chain fracture, and chemical structure changes. The study of bamboo aging during storage is an important part of the industrialization of bamboo as a substitute for plastic initiative. Photoaging during bamboo warehousing and its use is an important factor affecting performance and the use of the final product. To better evaluate the aging response mechanism caused by ambient light during bamboo warehousing, four aging conditions including ultraviolet light aging (UV-aging), indoor-light/light-avoidance cycle (Control), light avoidance (Avoid-light), and 90% RH (Avoid-light 90%) were simulated. The dimensional stability, mass, density, morphology, compressive mechanical strength, and other properties were monitored periodically according to 0, 7, 14, 28, 56, and 180 d. The change mechanism of bamboo under photoaging conditions was analyzed using SEM, FTIR, XRD, and TG. The synergistic effect of different factors under photoaging conditions was studied by redundancy analysis, and different photoaging environment prediction models were established using the long- and short-term memory (LTSM) model. The results showed that during the warehousing cycle of 180 d, the damage of light intensity to bamboo exposure was greater than that of the avoid-light treatment group, the humidity factor was negatively correlated with mechanical properties, the light factor was highly negatively correlated with dimensional stability, and the 30%–60% RH avoid-light condition showed excellent durability. The predictability of photoaging performance evaluation in a warehousing environment has important reference value for industry.

Unraveling the Phidiana paradox: Phidiana lynceus can retain algal symbionts but its nocturnal tendencies prevent benefits from photosynthesis

Numerous marine invertebrates form symbiotic relationships with single-celled algae, termed “photosymbioses”, and the diversity of these interactions is likely underestimated. We examined Phidiana lynceus, a cladobranch sea slug that feeds on photosymbiotic hydrozoans. We assessed its ability to acquire/retain algal symbionts by examining specimens in starvation, finding that P. lynceus is able to incorporate and retain symbionts for up to 20 days. Examining body size during starvation revealed that P. lynceus does not receive enough energy from hosting symbionts to maintain its body mass let alone grow. Intact symbionts were still present in deceased specimens, indicating that P. lynceus does not digest all of its symbionts, even when starving to death. We also examined slug behavior in the field and lab to determine if it seeks light to facilitate photosynthesis, which could provide energetic and oxygenic benefits. In the field, slugs were always observed hiding under stones during the day and they displayed light avoidance in the lab, suggesting this species actively prevents photosynthesis and the benefits it could receive. Lastly, we measured their metabolic rates during the day and night and when treated with and without a photosynthetic inhibitor. Higher metabolic rates at night indicate that this species displays nocturnal tendencies, expending more energy when it emerges at night to forage. Paradoxically, P. lynceus has evolved all of the requisite adaptations to profit from photosymbiosis but it chooses to live in the dark instead, calling into question the nature of this symbiosis and what each partner might receive from their interaction.

Retinal neurodegeneration induced by sodium iodate administration and visual cortex activity

Aims/Purpose: Recently investigations have shown that using sodium iodate (NaIO3) provides a promising animal model of retinal neurodegeneration. The aim of this research is to characterize the effects of this compound in the visual pathway.Methods: First, a single dose of NaIO3 (65 mg/kg) was administered intraperitoneally to mice (C57BL/6J strain) with a knock‐out mutation for the Opn4 gene (Opn4−/−). Then, behavioural tests (light avoidance assay, optomotor test, pupillary light reflex) were performed until Day 28. Electrophysiological tests (electroretinogram, ERG; visual evoked potentials, VEP), were performed weekly until Day 42. Finally, the retina was analysed histologically by immunohistochemical methods on day 57th.Results: First, the results of the behavioural test in the experimental group (NaIO3) reflected a progressive decrease in light sensitivity after 28 days, and a decrease in visual acuity and as well as a completely loss of the pupillary light reflex after 7 days since the administration. Second, the electrophysiological activity of retina and primary visual cortex (ERG, VEP) was significantly reduced in the treated group (NaIO3) with respect to the control group. Finally, histological analysis of the retina showed structural alterations in the outer segments of the photoreceptors of the treated animals (NaIO3).Conclusions: This research demonstrates the appearance of alterations in the outer retina and a decrease in the response at the level of the visual cortex after NaIO3 administration, as expected. This confirms that NaIO3‐induced retinal neurodegeneration is effective in obtaining a promising experimental model that could be used in the study of diseases associated with the visual system and in the development of novel therapeutic strategies.

Preference of juvenile tiger puffer for light spectrum and tank colours based on different body size and breeding background

As important environmental factors, the light spectra and tank colours have not received sufficient attention. Most fishes have the ability to perceive environment, distinguish colours, and exhibit preferences or aversions towards different environments, which can provide a reference for the design of their rearing environment. Tiger puffer (Takifugu rubripes) is an important mariculture species in China and East Asia, but its preference for illumination spectra and tank colours is unclear. This study focuses on the preferences of juvenile tiger puffers for different spectra and tank background colours in different rearing backgrounds and body sizes. The experiments were conducted in a preference testing device, and the behavioural videos were recorded and analysed using a motion behaviour tracking system (EthoVision XT 12). The results show that the puffers showed preference for short-wavelength lights ((i.e., cyan, green, etc.), avoidance of long-wavelength light (i.e., red) and less stay time in the full light spectrum and dark. For tank colours, the puffers showed a preference for light background colours (i.e., white), and avoidance of deep background colours (i.e., dark, red, etc.). Fish body sizes and original breeding environment could significantly affect the selective preference of juvenile puffer (P < 0.05). Large puffers preferred green tank colour than small ones, while small ones preferred grey and red. The puffers reared in green light and grey tank for 3 months preferred green light spectrum and green tank colour compared with those reared in full spectrum and grey tank, while the fish reared in full spectrum preferred grey tank colour and area without light. It was also found that the movement rate of juvenile puffers was affected by the light spectra and tank colours and was positively correlated with light wavelength (P < 0.05). Therefore, for tiger puffer breeding, short-wavelength light spectrums (cyan, green, etc.) and light-coloured tank backgrounds (white) are recommended. Long-wavelength Light-emitting diodes and dark tank colours should be avoided in breeding. This study would provide a reference basis for fish light spectra and background colour preference studies, as well as for the improvement of breeding welfare and production efficiency of juvenile tiger puffer.

P23 Curing the nail

Abstract Introduction Ultraviolet light is a well known trigger for inducing cutaneous flares in people who are predisposed or have been diagnosed with cutaneous lupus, it may have far reaching implications, triggering organ threatening disease Ultraviolet light could be from various sources including the sun, light bulbs and drying lamps used in nail salons to “cure the nails”. Curing the nails is a term used in the manicure world where UVA type 2 light is used to facilitate complete and quick drying of the nail polish: these type of UV light have been implicated in the pathogenesis of lupus. Case description This is the case of a 41 year old lady of African descent diagnosed with discoid lupus at the age of 33. Symptoms include hair loss, hypopigmented lesions on her ear, urticarial rash, fatigue, joint stiffness. Prior history of pregnancy loss at 14 weeks noted, and her sister also suffers from lupus. On examination she was found to have scarring alopecia with hyperkeratotic erythematous lesions at the periungual area with acrylic nails. Blood work showed lymphopenia, positive ANA, positive dsDNA by ELISA, RO+, positive anti smith antibody, normal complements and no evidence of kidney involvement. She was treated with topical therapy and then escalated in turns to hydroxychloroquine, mycophenolate mofetil, azathioprine, rituximab and methotrexate. She had developed a rash on hydroxychloroquine leading to it's discontinuation. The periungual lesions were resistant to all of the above treatment including intralesional steroid. She had recurrent flares of the lesions which resulted in episodes of infection, pus drainage, and treatment with antibiotics. Nifedipine was introduced but did not ameliorate symptoms A causal link was eventually made between her exposure to UV light at the nail salon and the periungual lesion. She was advised to discontinue using the UV light and possibly resort to traditional nail polish and air drying. The periungual lesions significantly improved on cessation of using the UV lights. Discussion Gel/acrylic manicures are becoming increasingly popular as they are more aesthetically pleasing and long lasting compared to traditional nail polish which uses air drying method, however we should be aware of the risk of ultraviolet (UV) light exposure which is used to dry the nails. UV light stimulates keratinocytes to express more small nuclear ribonucleoproteins thereby secreting IL-1,1L-6, IL-3, GM-CSF which lead to tissue damage and increased autoantibody production, this can result in development of cutaneous lupus, worsening of cutaneous lupus or in some cases can precipitate organ threatening systemic lupus. As clinicians we should be aware of the risks and educate our patients on the implication to their disease, they should be encouraged not to use this method of manicure but rather resort to the traditional nail polish which uses air drying technique rather than UV light. Other options may include applying sun protection cream to the fingers before manicure or the use of UV protective gloves, these measures though may not provide adequate coverage to the periungual area. We should be aware and educate our patients on avoidance of other sources of UV light including avoidance of fluorescent light, tanning beds, surgical lamps and measures to reduce exposure. Key learning points Consider other sources of UV light exposure in patients with hard to treat skin disease. It is critical that we educate our patients on the possible side effects of UV exposure and counsel on strategies to minimise exposure

Fényvédelem a photodermatosisok kezelésében

Light-sensitive skin diseases are known as photodermatoses. Photosensitivity is either an increased and/or unusual reaction to normal light, or an unusual skin reaction –as clinical symptoms-. to lower dose or different composition of light. Genetic and environmental factors have different characteristic roles in their development. Symptoms may develop through metabolic, immunological, or unknown (idiopathic) mechanisms. In many cases, the avoidance of the triggering light and sun protection are of important in the prevention of skin symptoms and in the treatment of photodermatoses. However, the patients' quality of life is negatively affected not only by the symptoms, but also by the daily application of sun protection itself. In this article, the authors highlight that in different photodermatoses, depending on their pathomechanism, different special photoprotection is necessary, and the methods used in the average population are not sufficient. Therefor, the use of disease (action spectrum) – specific, effective, and as simple as possible photoprotection methods is desirable.

Clues from planarians about interleukin-17A and stress that result from light avoidance: IL-17A antagonists reduce defensive responding in flatworms

Emerging evidence links interleukin-17A (IL-17A) to anxiety and stress. Circulating levels of IL-17A are elevated in patients with anxiety disorders, and pharmacological blockade of IL-17 signaling or genetic deletion of IL-17 reduces anxiety-like behaviors in mice. Given that IL-17 is one of the most conserved cytokines among animal phyla, we tested the hypothesis that anti-IL-17 treatments reduce defensive responding in planarians, the simplest animal with bilateral symmetry and a CNS with cephalization. The endpoint selected was light avoidance, which is a common phenotype of planarians and rodents and an index of defensive responding that is reduced by anxiolytic compounds in both species. Planarians were placed at the midline of a Petri dish containing water or test solution that was equally split into light and dark halves. Planarians exposed to a selective IL-17A antibody (0.1, 1, 10 pM) over a 5-min interval spent more time in the light than water-exposed planarians. Cyanidin (0.01, 0.1 1, 10 µM), an anti-inflammatory flavonoid and non-selective IL-17A inhibitor, also increased time spent in the light. Motility was not affected by IL-17A antibody or cyanidin at concentrations that reduced light avoidance, although higher concentrations reduced motility (>10 µM). Our results show that IL-17A antagonists reduce defensive responding in planarians and suggest conservation of IL-17A effects on aspects of anxiety-related behaviors.

Chloroplast photoprotection: face the light or run and hide?

Chloroplast photoprotection: face the light or run and hide?

MIZU-KUSSEI1 (MIZ1) and GNOM/MIZ2 control not only positive hydrotropism but also phototropism in Arabidopsis roots.

In response to unilateral blue light illumination, roots of some plant species such as Arabidopsis thaliana exhibit negative phototropism (bending away from light), which is important for light avoidance in nature. MIZU-KUSSEI1 (MIZ1) and GNOM/MIZ2 are essential for positive hydrotropism (i.e. in the presence of a moisture gradient, root bending towards greater water availability). Intriguingly, mutations in these genes also cause a substantial reduction in phototropism. Here, we examined whether the same tissue-specific sites of expression required for MIZ1- and GNOM/MIZ2-regulated hydrotropism in Arabidopsis roots are also required for phototropism. The attenuated phototropic response of miz1 roots was completely restored when a functional MIZ1-green fluorescent protein (GFP) fusion was expressed in the cortex of the root elongation zone but not in other tissues such as root cap, meristem, epidermis, or endodermis. The hydrotropic defect and reduced phototropism of miz2 roots were restored by GNOM/MIZ2 expression in either the epidermis, cortex, or stele, but not in the root cap or endodermis. Thus, the sites in root tissues that are involved in the regulation of MIZ1- and GNOM/MIZ2-dependent hydrotropism also regulate phototropism. These results suggest that MIZ1- and GNOM/MIZ2-mediated pathways are, at least in part, shared by hydrotropic and phototropic responses in Arabidopsis roots.

Melasma is Associated with Lower Serum Vitamin D Concentrations as Compared to Healthy Controls

Background Melasma is a common, chronic skin condition of hyperpigmentation involving the appearance of symmetric and irregular light brown macules and patches, mainly on sun exposed skin of the head and neck. Though the pathogenesis is not fully understood, hyperfunctional melanocytes are known to deposit excess melanin in the epidermis and dermis. Known risk factors or triggers include genetic influence, hormonal influence, and ultraviolet radiation. Due to the avoidance of ultraviolet light, vitamin D supplementation is recommended. Due to known influence of vitamin D on the skin and the large prevalence of melasma in the public, the association between vitamin D and melasma will be examined further. Methods A retrospective review was performed utilizing the TriNetX platform to query de-identified patient data from the Medical University of South Carolina’s Electronic Health Record system over a 9-year period from January 2013 to May 2022. Calcidiol (25-hydroxy-vitaminD) was utilized as a surrogate for Vitamin D level. Statistical analyses were performed using Chi-square tests. Results Of 1,962 patients diagnosed with melasma, 840 had a serum calcidiol level measured following diagnosis. The majority of these patients were female (77%) and had an average age of 60.3 + 19.2 years. Melasma patients were most commonly Caucasian (81%), followed by African American (15%) and Hispanic or Latino (3%). Patients with melasma had an average serum calcidiol of 33.8 + 15.8 ng/mL (reference range: 25 – 80 ng/mL). This was significantly lower than comparison to 2,146 dermatology patients not diagnosed with melasma (36.8 + 15.8 ng/mL, p-value &lt;0.0001%). Conclusion Vitamin D has been demonstrated to be critical in the skin, including differentiation and proliferation of melanocytes. Our results suggest that patients with melasma, who have significantly lower levels of serum vitamin D than their healthy counterparts, may benefit from vitamin D supplementation. Future studies investigating improvement in melasma symptoms following vitamin D supplementation are needed.

An evening light intervention reduces fatigue and errors during night shifts: A randomized controlled trial

ObjectiveShift work causes circadian rhythms to misalign with the demands of the environment, which has been associated with sleep difficulties and cognitive impairments. Although bright light exposure during night shifts can improve circadian alignment, its implementation is often infeasible. Here, we tested whether light exposure in the evening, before the night shift, could improve fatigue, work performance, mood, and sleep. MethodsFifty-seven healthy nurses who worked full-time rapidly rotating shift schedules completed the study. In a mixed-design randomized controlled trial, participants completed a baseline observation period before following 1 of 2 interventions. The experimental intervention aimed to improve circadian alignment using evening light exposure and morning light avoidance; the control intervention aimed to improve alertness and reduce sleep disturbances by modifying diet. Every morning and evening for 30 days, participants completed measures of fatigue, work-related errors, sleepiness, mood, sleep duration, and sleep quality. ResultsCompared to the baseline observation period, the experimental intervention reduced errors by 67%, while the control intervention reduced them by only 5%. This reduction was partially mediated by fatigue; experimental participants reported less fatigue on work days than control participants (d = 0.25 [0.10, 0.38]). The experimental group also showed a small improvement in mood. Both groups showed reductions in fatigue (d = 0.29 [0.20, 0.36]) and sleepiness (d = 0.21 [0.12, 0.28]) as well as a small increase in sleep duration. ConclusionsInterventions based on evening light may be a feasible and effective strategy to reduce fatigue and errors in night-shift workers.