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Poultry Science Jun 2024Environmental conditions during incubation and rearing can influence stress responsivity of laying hen pullets throughout their lifespan, and therefore have important...
Environmental conditions during incubation and rearing can influence stress responsivity of laying hen pullets throughout their lifespan, and therefore have important implications for their welfare. In this study, a 12:12h green LED light-dark cycle during incubation and larvae provisioning as enrichment during rearing were tested as strategies to optimize early-life conditions and thereby decrease stress responsivity in ISA Brown laying hens. A combination of parameters was measured to indicate neuronal, physiological, and behavioral changes that may affect fear and stress. The proteins calbindin D28k (calbindin1), doublecortin (DCX), and neuronal nuclein protein (NeuN) were quantified after hatch as a proxy for brain plasticity. Plasma and feather corticosterone levels were measured after hatch and at the end of the rearing phase, and fearfulness was investigated through a series of behavioral tests (i.e., voluntary approach, open field, tonic immobility, and manual restraint tests). No effects of light during incubation were found on calbindin1, DCX, or NeuN. Neither of the treatments affected corticosterone levels in blood plasma and feathers. Light-incubated pullets showed less fearfulness towards humans in the voluntary approach test, but not in the other behavioral tests reported in this study. Larvae provisioning had no effect on behavior. Our study showed minor effects of light during incubation and no effects of enrichment during rearing on stress responsivity of laying hen pullets. The small effects may be explained by the enriched rearing conditions for all birds in this experiment (low stocking density, natural daylight, and 24/7 classical music). Given the promising results of lighted incubation in other studies, which were mostly performed in broiler chickens, and evidence regarding the positive effects of enrichment during rearing, the potential of these strategies to improve laying hen welfare needs to be explored further.
Topics: Animals; Chickens; Corticosterone; Female; Fear; Animal Husbandry; Neuronal Plasticity; Behavior, Animal; Animal Welfare; Feathers
PubMed: 38569241
DOI: 10.1016/j.psj.2024.103665 -
Biomimetics (Basel, Switzerland) Mar 2024Nighttime object detection is challenging due to dim, uneven lighting. The IIHS research conducted in 2022 shows that pedestrian anti-collision systems are less...
Nighttime object detection is challenging due to dim, uneven lighting. The IIHS research conducted in 2022 shows that pedestrian anti-collision systems are less effective at night. Common solutions utilize costly sensors, such as thermal imaging and LiDAR, aiming for highly accurate detection. Conversely, this study employs a low-cost 2D image approach to address the problem by drawing inspiration from biological dark adaptation mechanisms, simulating functions like pupils and photoreceptor cells. Instead of relying on extensive machine learning with day-to-night image conversions, it focuses on image fusion and gamma correction to train deep neural networks for dark adaptation. This research also involves creating a simulated environment ranging from 0 lux to high brightness, testing the limits of object detection, and offering a high dynamic range testing method. Results indicate that the dark adaptation model developed in this study improves the mean average precision (mAP) by 1.5-6% compared to traditional models. Our model is capable of functioning in both twilight and night, showcasing academic novelty. Future developments could include using virtual light in specific image areas or integrating with smart car lighting to enhance detection accuracy, thereby improving safety for pedestrians and drivers.
PubMed: 38534843
DOI: 10.3390/biomimetics9030158 -
Frontiers in Plant Science 2024Anthocyanin is an important pigment that prevents oxidative stress and mediates adaptation of plants to salt stress. Peanuts with dark red and black testa are rich in...
Anthocyanin is an important pigment that prevents oxidative stress and mediates adaptation of plants to salt stress. Peanuts with dark red and black testa are rich in anthocyanin. However, correlation between salt tolerance and anthocyanin content in black and dark red testa peanuts is unknown. In this study, three peanut cultivars namely YZ9102 (pink testa), JHR1 (red testa) and JHB1 (black testa) were subjected to sodium chloride (NaCl) stress. The plant growth, ion uptake, anthocyanin accumulation, oxidation resistance and photosynthetic traits were comparatively analyzed. We observed that the plant height, leaf area and biomass under salt stress was highly inhibited in pink color testa (YZ9102) as compare to black color testa (JHB1). JHB1, a black testa colored peanut was identified as the most salt-tolerance cultivar, followed by red (JHR1) and pink(YZ9102). During salt stress, JHB1 exhibited significantly higher levels of anthocyanin and flavonoid accumulation compared to JHR1 and YZ9102, along with increased relative activities of antioxidant protection and photosynthetic efficiency. However, the K/Na and Ca/Na were consistently decreased among three cultivars under salt stress, suggesting that the salt tolerance of black testa peanut may not be related to ion absorption. Therefore, we predicted that salt tolerance of JHB1 may be attributed to the accumulation of the anthocyanin and flavonoids, which activated antioxidant protection against the oxidative damage to maintain the higher photosynthetic efficiency and plant growth. These findings will be useful for improving salt tolerance of peanuts.
PubMed: 38529061
DOI: 10.3389/fpls.2024.1368260 -
Frontiers in Molecular Neuroscience 2024Adaptation of photoreceptor sensitivity to varying light intensities is a fundamental requirement for retinal function and vision. Adaptive mechanisms in signal...
Adaptation of photoreceptor sensitivity to varying light intensities is a fundamental requirement for retinal function and vision. Adaptive mechanisms in signal transduction are well described, but little is known about the mechanisms that adapt the photoreceptor synapse to changing light intensities. The SNARE complex regulators Complexin 3 and Complexin 4 have been proposed to be involved in synaptic light adaptation by limiting synaptic vesicle recruitment and fusion. How this Complexin effect is exerted is unknown. Focusing on rod photoreceptors, we established Complexin 4 as the predominant Complexin in the light-dependent regulation of neurotransmitter release. The number of readily releasable synaptic vesicles is significantly smaller in light than in dark at wildtype compared to Complexin 4 deficient rod photoreceptor ribbon synapses. Electrophysiology indicates that Complexin 4 reduces or clamps Ca-dependent sustained synaptic vesicle release, thereby enhancing light signaling at the synapse. Complexin 4 deficiency increased synaptic vesicle release and desensitized light signaling. In a quantitative proteomic screen, we identified Transducin as an interactor of the Complexin 4-SNARE complex. Our results provide evidence for a presynaptic interplay of both Complexin 4 and Transducin with the SNARE complex, an interplay that may facilitate the adaptation of synaptic transmission to light at rod photoreceptor ribbon synapses.
PubMed: 38481472
DOI: 10.3389/fnmol.2024.1308466 -
Impact of flight and equivalent short-term high-altitude exposure on ocular structures and function.Medical Hypothesis, Discovery &... 2023Exposure to high-altitude conditions during flight or similar activities affects many aspects of visual function, which is critical not only for flight safety but for... (Review)
Review
BACKGROUND
Exposure to high-altitude conditions during flight or similar activities affects many aspects of visual function, which is critical not only for flight safety but for any altitude-related activity. We aimed to summarize the available literature pertaining to ocular changes during flight or equivalent short-term high-altitude exposure (e.g., hypobaric chamber, effortless ascent lasting ≤ 24 h) and to highlight future research priorities.
METHODS
Using the PubMed/MEDLINE and Web of Science/ISI Web of Knowledge databases with structured search syntax, we conducted a systematic review of the literature spanning a 40-year period (January 1, 1983, to October 10, 2023). Articles pertaining to ocular changes during flight or flight-equivalent exposure to altitude were retrieved. The reference lists of retrieved studies were also searched, and citations of these references were included in the results.
RESULTS
Of 875 relevant PubMed and ISI publications, 122 qualified for inclusion and 20 more were retrieved from the reference lists of initially selected records, for a total of 142 articles. Reported anterior segment changes included deterioration in tear film stability and increased dry eye incidence, increased corneal thickness, discomfort and bubble formation in contact lens users, refraction changes in individuals with prior refractive surgery, decreased intraocular pressure, and alterations in pupillary reaction, contrast sensitivity, and visual fields. Photoreceptor-visual pathway changes included alterations in both photoreceptors and neuro-transduction, as evidenced in dark adaptation, macular recovery time, reduction in visual field sensitivity, and optic neuritis (likely an element of decompression sickness). Retinochoroidal changes included increases in retinal vessel caliber, retinal blood flow, and choroidal thickness; central serous chorioretinopathy; and retinal vascular events (non-arteritic ischemic optic neuropathy, high-altitude retinopathy, and retinal vein occlusion).
CONCLUSIONS
The effect of short-term high-altitude exposure on the eye is, in itself, a difficult area to study. Although serious impairment of visual acuity appears to be rare, ocular changes, including tear film stability, contact lens wear, central corneal thickness, intraocular pressure, contrast sensitivity, stability of refractive surgeries, retinal vessels, visual fields, and macula recovery time, should be considered in civilian aviators. Our report provides guidance to climbers and lowlanders traveling to altitude if they have pre-existing ocular conditions or if they experience visual symptoms while at altitude. However, key outcomes have been contradictory and comprehensive studies are scarce, especially those pertaining to the choroid and retina. Such studies could not only deepen our understanding of high-altitude ocular pathophysiology, but could also offer valuable information and treatment possibilities for a constellation of other vision-threatening diseases.
PubMed: 38476577
DOI: 10.51329/mehdiophthal1478 -
Investigative Ophthalmology & Visual... Mar 2024The purpose of this study was to investigate rod photopigment bleaching-driven intrinsic optical signals (IOS) in the human outer retina and its measurement...
PURPOSE
The purpose of this study was to investigate rod photopigment bleaching-driven intrinsic optical signals (IOS) in the human outer retina and its measurement repeatability based on a commercial optical coherence tomography (OCT) platform.
METHODS
The optical path length of the rod photoreceptor subretinal space (SRS), that is, the distance between signal bands of rod outer segment tips and retinal pigment epithelium, was measured in 15 healthy subjects in ambient light and during a long-duration bleaching white-light exposure.
RESULTS
On 2 identical study days (day 1 and day 2 [D1 and D2]), light stimulation resulted in a significant decrease in rod SRS by 21.3 ± 7.6% and 19.8 ± 8.5% (both P < 0.001), respectively. The test-retest reliability of the SRS maximum change of an individual subject was moderate for single measures (intraclass correlation coefficient [ICC] = 0.730, 95% confidence interval [CI] = 0.376, 0.900, P < 0.001) and good for average measures (ICC = 0.844, 95% CI = 0.546, 0.947, P < 0.001). The mean area under the stimulus response curve with values of 14.8 ± 9.4 and 15.5 ± 7.5 µm × minutes (P = 0.782) showed excellent agreement between the stimulus response on D1 and D2. Intermittent dark adaptation of the retina led to an initial increase of the SRS by 6.1% (P = 0.018) and thereafter showed a decrease toward baseline, despite continued dark adaptation.
CONCLUSIONS
The data indicate the potential of commercial OCT in measuring slow IOS in the outer retina suggesting that the rod SRS could serve as a biomarker for photoreceptor function. The presented approach could provide an easily implementable clinical tool for the early detection of diseases affecting photoreceptor health.
Topics: Humans; Reproducibility of Results; Tomography, Optical Coherence; Retina; Dark Adaptation; Rod Cell Outer Segment
PubMed: 38470325
DOI: 10.1167/iovs.65.3.20 -
Applied Microbiology and Biotechnology Mar 2024Environmental concerns about residues and the traditional disposal methods are driving the search for more environmentally conscious processes, such as pyrolysis and...
Environmental concerns about residues and the traditional disposal methods are driving the search for more environmentally conscious processes, such as pyrolysis and gasification. Their main final product is synthesis gas (syngas) composed of CO, CO, H, and methane. Syngas can be converted into various products using CO-tolerant microorganisms. Among them, Rhodospirillum rubrum is highlighted for its biotechnological potential. However, the extent to which high doses of CO affect its physiology is still opaque. For this reason, we have studied R. rubrum behavior under high levels of this gas (up to 2.5 bar), revealing a profound dependence on the presence or absence of light. In darkness, the key variable affected was the lag phase, where the highest levels of CO retarded growth to more than 20 days. Under light, R. rubrum ability to convert CO into CO and H depended on the presence of an additional carbon source, such as acetate. In those conditions where CO was completely exhausted, CO fixation was unblocked, leading to a diauxic growth. To enhance R. rubrum tolerance to CO in darkness, a UV-accelerated adaptive laboratory evolution (UVa-ALE) trial was conducted to isolate clones with shorter lag phases, resulting in the isolation of clones 1.4-2B and 1.7-2A. The adaptation of 1.4-2B was mainly based on mutated enzymes with a metabolic function, while 1.7-3A was mostly affected at regulatory genes, including the anti-repressor PpaA/AerR. Despite these mutations having slight effects on biomass and pigment levels, they successfully provoked a significant reduction in the lag phase (-50%). KEYPOINTS: • CO affects principally R. rubrum lag phase (darkness) and growth rate (light) • CO is converted to CO/H during acetate uptake and inhibits CO fixation (light) • UVa-ALE clones showed a 50% reduction in the lag phase (darkness).
Topics: Carbon Monoxide; Rhodospirillum rubrum; Carbon Dioxide; Acetates
PubMed: 38466440
DOI: 10.1007/s00253-024-13079-5 -
Investigative Ophthalmology & Visual... Mar 2024A progression sequence for age-related macular degeneration onset may be determinable with consensus neuroanatomical nomenclature augmented by drusen biology and... (Review)
Review
A progression sequence for age-related macular degeneration onset may be determinable with consensus neuroanatomical nomenclature augmented by drusen biology and eye-tracked clinical imaging. This narrative review proposes to supplement the Early Treatment of Diabetic Retinopathy Study (sETDRS) grid with a ring to capture high rod densities. Published photoreceptor and retinal pigment epithelium (RPE) densities in flat mounted aged-normal donor eyes were recomputed for sETDRS rings including near-periphery rich in rods and cumulatively for circular fovea-centered regions. Literature was reviewed for tissue-level studies of aging outer retina, population-level epidemiology studies regionally assessing risk, vision studies regionally assessing rod-mediated dark adaptation (RMDA), and impact of atrophy on photopic visual acuity. The 3 mm-diameter xanthophyll-rich macula lutea is rod-dominant and loses rods in aging whereas cone and RPE numbers are relatively stable. Across layers, the largest aging effects are accumulation of lipids prominent in drusen, loss of choriocapillary coverage of Bruch's membrane, and loss of rods. Epidemiology shows maximal risk for drusen-related progression in the central subfield with only one third of this risk level in the inner ring. RMDA studies report greatest slowing at the perimeter of this high-risk area. Vision declines precipitously when the cone-rich central subfield is invaded by geographic atrophy. Lifelong sustenance of foveal cone vision within the macula lutea leads to vulnerability in late adulthood that especially impacts rods at its perimeter. Adherence to an sETDRS grid and outer retinal cell populations within it will help dissect mechanisms, prioritize research, and assist in selecting patients for emerging treatments.
Topics: Humans; Adult; Aged; Macular Degeneration; Retina; Macula Lutea; Geographic Atrophy; Retinal Cone Photoreceptor Cells
PubMed: 38466281
DOI: 10.1167/iovs.65.3.4 -
Experimental Biology and Medicine... 2024This research aims to investigate the potential of using intrinsic optical signal (IOS) optoretinography (ORG) to objectively detect dark adaptation (DA) abnormalities...
This research aims to investigate the potential of using intrinsic optical signal (IOS) optoretinography (ORG) to objectively detect dark adaptation (DA) abnormalities related to rod photoreceptor degeneration. Functional optical coherence tomography (OCT) was employed in both wild-type (WT) and retinal degeneration 10 (rd10) mice to conduct this assessment. Dynamic OCT measurements captured the changes in retinal thickness and reflectance from light-to-dark transition. Comparative analysis revealed significant IOS alterations within the outer retina. Specifically, a reduction in thickness from external limiting membrane (ELM) peak to retinal pigment epithelium (RPE) peak was observed (WT: 1.13 ± 0.69 µm, 30 min DA; rd10: 2.64 ± 0.86 µm, 30 min DA), as well as a decrease in the intensity of the inner segment ellipsoid zone (EZ) in 30 min DA compared to light adaptation (LA). The reduction of relative EZ intensity was notable in rd10 after 5 min DA and in WT after 15 min DA, with a distinguishable difference between rd10 and WT after 10 min DA. Furthermore, our findings indicated a significant decrease in the relative intensity of the hypo-reflective band between EZ and RPE in rd10 retinas during DA, which primarily corresponds to the outer segment (OS) region. In conclusion, the observed DA-IOS abnormalities, including changes in ELM-RPE thickness, EZ, and OS intensity, hold promise as differentiators between WT and rd10 mice before noticeable morphological abnormalities occur. These findings suggest the potential of this non-invasive imaging technique for the early detection of dysfunction in retinal photoreceptors.
Topics: Mice; Animals; Retinal Degeneration; Dark Adaptation; Retina; Retinal Pigment Epithelium; Retinal Rod Photoreceptor Cells
PubMed: 38463390
DOI: 10.3389/ebm.2024.10024 -
Documenta Ophthalmologica. Advances in... Jun 2024Leber hereditary optic neuropathy (LHON) affects retinal ganglion cells causing severe vision loss. Pattern electroretinogram and photopic negative response (PhNR) of...
PURPOSE
Leber hereditary optic neuropathy (LHON) affects retinal ganglion cells causing severe vision loss. Pattern electroretinogram and photopic negative response (PhNR) of the light-adapted (LA) full-field electroretinogram (ERG) are typically affected in LHON. In the present study, we evaluated dark-adapted (DA) and LA oscillatory potentials (OPs) of the flash ERG in genetically characterized LHON patients to dissociate slow from fast components of the response.
METHODS
Seven adult patients (mean age = 28.4 ± 5.6) in whom genetic diagnosis confirmed LHON with mtDNA or nuclear DNAJC30 (arLHON) pathogenic variants were compared to 12 healthy volunteers (mean age = 35.0 ± 12.1). Full-field ERGs were recorded from both eyes. Offline digital filters at 50, 75 and 100 Hz low cutoff frequencies were applied to isolate high-frequency components from the original ERG signals.
RESULTS
ERG a-waves and b-waves were comparable between LHON patients and controls, while PhNR was significantly reduced (p = 0.009) in LHON patients compared to controls, as expected. OPs derived from DA signals (75 Hz low cutoff frequency) showed reduced peak amplitude for OP2 (p = 0.019). LA OP differences between LHON and controls became significant (OP2: p = 0.047, OP3: p = 0.039 and OP4: p = 0.013) when the 100 Hz low-cutoff frequency filter was applied.
CONCLUSIONS
Reduced OPs in LHON patients may represent disturbed neuronal interactions in the inner retina with preserved photoreceptoral (a-wave) to bipolar cell (b-wave) activation. Reduced DA OP2 and high-cutoff LA OP alterations may be further explored as functional measures to characterize LHON status and progression.
Topics: Humans; Electroretinography; Optic Atrophy, Hereditary, Leber; Male; Adult; Female; Retinal Ganglion Cells; Photic Stimulation; Young Adult; Dark Adaptation; Middle Aged; Visual Acuity
PubMed: 38451375
DOI: 10.1007/s10633-024-09968-9