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Cell Reports May 2024Cellular retinaldehyde-binding protein (CRALBP) supports production of 11-cis-retinaldehyde and its delivery to photoreceptors. It is found in the retinal pigment...
Cellular retinaldehyde-binding protein (CRALBP) supports production of 11-cis-retinaldehyde and its delivery to photoreceptors. It is found in the retinal pigment epithelium (RPE) and Müller glia (MG), but the relative functional importance of these two cellular pools is debated. Here, we report RPE- and MG-specific CRALBP knockout (KO) mice and examine their photoreceptor and visual cycle function. Bulk visual chromophore regeneration in RPE-KO mice is 15-fold slower than in controls, accounting for their delayed rod dark adaptation and protection against retinal phototoxicity, whereas MG-KO mice have normal bulk visual chromophore regeneration and retinal light damage susceptibility. Cone pigment regeneration is significantly impaired in RPE-KO mice but mildly affected in MG-KO mice, disclosing an unexpectedly strong reliance of cone photoreceptors on the RPE-based visual cycle. These data reveal a dominant role for RPE-CRALBP in supporting rod and cone function and highlight the importance of RPE cell targeting for CRALBP gene therapies.
Topics: Animals; Mice; Carrier Proteins; Ependymoglial Cells; Mice, Inbred C57BL; Mice, Knockout; Retinal Cone Photoreceptor Cells; Retinal Pigment Epithelium; Retinal Pigments; Retinal Rod Photoreceptor Cells; Male; Female
PubMed: 38676924
DOI: 10.1016/j.celrep.2024.114143 -
Ecology and Evolution Apr 2024Cave-adapted animals evolve a suite of regressive and constructive traits that allow survival in the dark. Most studies aiming at understanding cave animal evolution... (Review)
Review
Cave-adapted animals evolve a suite of regressive and constructive traits that allow survival in the dark. Most studies aiming at understanding cave animal evolution have focused on the genetics and environmental underpinnings of regressive traits, with special emphasis on vision loss. Possibly as a result of vision loss, other non-visual sensory systems have expanded and compensated in cave species. For instance, in many cave-dwelling fish species, including the blind cavefish of the Mexican tetra, , a major non-visual mechanosensory system called the lateral line, compensated for vision loss through morphological expansions. While substantial work has shed light on constructive adaptation of this system, there are still many open questions regarding its developmental origin, synaptic plasticity, and overall adaptive value. This review provides a snapshot of the current state of knowledge of lateral line adaption in , with an emphasis on anatomy, synaptic plasticity, and behavior. Multiple open avenues for future research in this system, and how these can be leveraged as tools for both evolutionary biology and evolutionary medicine, are discussed.
PubMed: 38654714
DOI: 10.1002/ece3.11286 -
Frontiers in Behavioral Neuroscience 2024The purpose of this review extends beyond the traditional triune brain model, aiming to elucidate the evolutionary aspects of alpha rhythms in vertebrates. The... (Review)
Review
The purpose of this review extends beyond the traditional triune brain model, aiming to elucidate the evolutionary aspects of alpha rhythms in vertebrates. The forebrain, comprising the telencephalon (pallium) and diencephalon (thalamus, hypothalamus), is a common feature in the brains of all vertebrates. In mammals, evolution has prioritized the development of the forebrain, especially the neocortex, over the midbrain (mesencephalon) optic tectum, which serves as the prototype for the visual brain. This evolution enables mammals to process visual information in the retina-thalamus (lateral geniculate nucleus)-occipital cortex pathway. The origin of posterior-dominant alpha rhythms observed in mammals in quiet and dark environments is not solely attributed to cholinergic pontine nuclei cells functioning as a 10 Hz pacemaker in the brainstem. It also involves the ability of the neocortex's cortical layers to generate traveling waves of alpha rhythms with waxing and waning characteristics. The utilization of alpha rhythms might have facilitated the shift of attention from external visual inputs to internal cognitive processes as an adaptation to thrive in dark environments. The evolution of alpha rhythms might trace back to the dinosaur era, suggesting that enhanced cortical connectivity linked to alpha bands could have facilitated the development of nocturnal awakening in the ancestors of mammals. In fishes, reptiles, and birds, the pallium lacks a cortical layer. However, there is a lack of research clearly observing dominant alpha rhythms in the pallium or organized nuclear structures in fishes, reptiles, or birds. Through convergent evolution, the pallium of birds, which exhibits cortex-like fiber architecture, has not only acquired advanced cognitive and motor abilities but also the capability to generate low-frequency oscillations (4-25 Hz) resembling alpha rhythms. This suggests that the origins of alpha rhythms might lie in the pallium of a common ancestor of birds and mammals.
PubMed: 38651071
DOI: 10.3389/fnbeh.2024.1384340 -
American Journal of Botany Apr 2024Endophytic and mycorrhizal fungi are crucial in facilitating plant nutrition acquisition and stress tolerance. In epiphytic habitats, plants face nutrition and water...
PREMISE
Endophytic and mycorrhizal fungi are crucial in facilitating plant nutrition acquisition and stress tolerance. In epiphytic habitats, plants face nutrition and water stress, but their roots are mostly nonmycorrhizal and especially lacking in arbuscular mycorrhizal associations. Ophioderma pendulum is an epiphytic fern with a partially mycoheterotrophic lifestyle, likely heavily reliant on symbiotic fungi. To characterize fungal associations in the sporophyte of O. pendulum, we focused on leaves and roots of O. pendulum, seeking to reveal the fungal communities in these organs.
METHODS
Roots and leaves from O. pendulum in a subtropical forest were examined microscopically to observe the morphology of fungal structures and determine the percentage of various fungal structures in host tissues. Fungal composition was profiled using metabarcoding techniques that targeted ITS2 of the nuclear ribosomal DNA.
RESULTS
Roots were consistently colonized by arbuscular mycorrhizal fungi (Glomeromycota), especially Acaulospora. Unlike previous findings on epiphytic ferns, dark septate endophytes were rare in O. pendulum roots. Leaves were predominantly colonized by Ascomycota fungi, specifically the classes Dothideomycetes (46.88%), Eurotiomycetes (11.51%), Sordariomycetes (6.23%), and Leotiomycetes (6.14%). Across sampling sites, fungal community compositions were similar in the roots but differed significantly in the leaves.
CONCLUSIONS
Ophioderma pendulum maintains stable, single-taxon-dominant communities in the roots, primarily featuring arbuscular mycorrhizal fungi, whereas the leaves may harbor opportunistic fungal colonizers. Our study underlines the significance of mycorrhizal fungi in the adaptation of epiphytic ferns.
PubMed: 38641926
DOI: 10.1002/ajb2.16319 -
Translational Vision Science &... Apr 2024The purpose of this study was to determine and compare binocular summation (BiS) of conventional visual acuity (cVA) versus hyperacuity (hVA) for photopic and scotopic...
PURPOSE
The purpose of this study was to determine and compare binocular summation (BiS) of conventional visual acuity (cVA) versus hyperacuity (hVA) for photopic and scotopic luminance conditions as a potential biomarker to assess the outcome of interventions on binocular function.
METHODS
Sixteen young adults (age range [years] = 21-31; 8 women; cVA logMAR < 0.0) participated in this study. The Freiburg Visual Acuity Test (FrACT) was used for VA testing and retested on another day. Both cVA and hVA were determined for dark grey optotypes on light grey background. Participants underwent 40 minutes of dark adaptation prior to scotopic VA testing. Binocular and monocular VA testing was performed. The eye with better VA over the 2 days of testing was selected, the BiS was quantified (binocular VA - better monocular VA) and repeated measures ANOVAs were performed.
RESULTS
Binocular VA exceeded monocular VA for all luminance conditions, VA-types, and sessions. We report BiS estimates for photopic and scotopic cVA and hVA, (logMAR BiS ± SEM [decimal BiS]): photopic = -0.01 ± 0.01 [1.03] and -0.06 ± 0.03 [1.15]; and scotopic = -0.05 ± 0.01 [1.12] and -0.11 ± 0.04 [1.28], respectively). Improvement for binocular vision estimates ranged from 0.01 to 0.11 logMAR. A repeated-measures ANOVA (RM ANOVA) did not reveal significant effects of LUMINANCE or VA TYPE on BiS, albeit a trend for strongest BiS for scotopic hVA (15% vs. 28%, photopic versus scotopic, respectively) and weakest for photopic cVA (3% vs. 12%, photopic versus scotopic conditions, respectively).
CONCLUSIONS
Our results indicate that BiS of VA is relevant to scotopic and photopic hVA and cVA. It appears therefore a plausible candidate biomarker to assess the outcome of retinal therapies restoring rod or cone function on binocular vision.
TRANSLATIONAL RELEVANCE
Binocular summation of visual acuity might serve as a clinical biomarker to monitor therapy outcome on binocular rod and cone-mediated vision.
Topics: Young Adult; Humans; Female; Adult; Visual Acuity; Vision Tests; Vision, Binocular; Vision, Ocular; Biomarkers
PubMed: 38639931
DOI: 10.1167/tvst.13.4.25 -
Journal of Glaucoma Jul 2024This case study reports on the presence of vitamin A deficiency in an adult with asymmetric normal tension glaucoma. The retinal OCT findings demonstrated not only...
This case study reports on the presence of vitamin A deficiency in an adult with asymmetric normal tension glaucoma. The retinal OCT findings demonstrated not only expected loss of the outer retinal layers, typically seen in vitamin A deficiency, but also severe and bilateral loss of the inner retinal layers. After vitamin A supplementation, visual acuity, dark adaptation, and color vision normalized. The outer retinal layers had a restoration of thickness after vitamin A supplementation, but the inner layers did not change. This case is unique because it may give us an insight into the role of vitamin A on the inner retina and demonstrate the recovery of the outer retinal layers with vitamin A supplementation.
Topics: Humans; Tomography, Optical Coherence; Vitamin A Deficiency; Vitamin A; Visual Acuity; Intraocular Pressure; Low Tension Glaucoma; Middle Aged; Female; Male; Retinal Ganglion Cells; Vitamins; Dark Adaptation; Visual Fields
PubMed: 38619392
DOI: 10.1097/IJG.0000000000002405 -
Tropical Animal Health and Production Apr 2024Photoperiod manipulation is emerging as an effective approach for regulating physiological functions in fish. This study aimed to assess the impact of photoperiod on the...
Photoperiod manipulation is emerging as an effective approach for regulating physiological functions in fish. This study aimed to assess the impact of photoperiod on the growth performance, haematological responses, and economic returns of the endangered and highly valued Indian butter catfish, Ompok bimaculatus. Fish with an average body weight of 28.60 ± 4.78 g were randomly placed in six FRP tanks, each measuring 120 × 45 × 60 cm. Each tank contained 20 fish exposed to a light intensity of 1500 lx under different photoperiods [24:0 light: dark (L: D), 15 L: 9D, 12 L: 12D, 9 L: 15D, 0 L: 24D and a natural photoperiod (control)], and fed at a daily rate of 2% of their body weight twice daily for 60 days. The fish in the 15 L: 9D photoperiod exhibited the highest final weight (g), percentage weight gain, specific growth rate (SGR) and survival rate, while the lowest was displayed in 24 L: 0D photoperiod group. The feed conversion ratio (FCR) was at its lowest in the catfish subjected to the 15 L: 9D photoperiod. Regarding haematological parameters, the 15 L: 9D photoperiod group showed higher total erythrocyte count, total leukocyte count, haemoglobin levels, and haematocrit values compared to the other groups. Conversely, the 0 L: 24D group, which experienced prolonged darkness, exhibited the lowest values in these parameters. Moreover, the 24 L: 0D, 9 L: 15D, and 0 L: 24D groups displayed a lower mean corpuscular volume (MCV) but higher mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) when compared to the control group. The economic analysis revealed that O. bimaculatus reared in a moderate photoperiod (15 L: 9D) displayed better growth, feed utilization, and overall health. This finding suggests that adopting a 15 L: 9D photoperiod can lead to enhanced production and improved economic returns for farmers culturing this high-value catfish in the future.
Topics: Animals; Catfishes; Photoperiod; Body Weight; Erythrocyte Indices; Hematocrit
PubMed: 38613714
DOI: 10.1007/s11250-024-03981-5 -
Plants (Basel, Switzerland) Mar 2024The adaptation of plants to combined stresses requires unique responses capable of overcoming both the negative effects of each individual stress and their combination....
The adaptation of plants to combined stresses requires unique responses capable of overcoming both the negative effects of each individual stress and their combination. Here, we studied the C-C (C) halophyte in response to elevated temperature (35 °C) and salinity (300 mM NaCl) as well as their combined effect. The responses we studied included changes in water-salt balance, light and dark photosynthetic reactions, the expression of photosynthetic genes, the activity of malate dehydrogenase complex enzymes, and the antioxidant system. Salt treatment led to altered water-salt balance, improved water use efficiency, and an increase in the abundance of key enzymes involved in intermediate C-C photosynthesis (i.e., Rubisco and glycine decarboxylase). We also observed a possible increase in the activity of the C carbon-concentrating mechanism (CCM), which allowed plants to maintain high photosynthesis intensity and biomass accumulation. Elevated temperatures caused an imbalance in the dark and light reactions of photosynthesis, leading to stromal overreduction and the excessive generation of reactive oxygen species (ROS). In response, significantly activated a metabolic pathway for removing excess NADPH, the malate valve, which is catalyzed by NADP-MDH, without observable activation of the antioxidant system. The combined action of these two factors caused the activation of antioxidant defenses (i.e., increased activity of SOD and POX and upregulation of ), which led to a decrease in oxidative stress and helped restore the photosynthetic energy balance. Overall, improved PSII functioning and increased activity of PSI cyclic electron transport (CET) and C CCM led to an increase in the photosynthesis intensity of under the combined effect of salinity and elevated temperature relative to high temperature alone.
PubMed: 38592796
DOI: 10.3390/plants13060800 -
Zoological Science Feb 2024The endocrine and neuroendocrine systems exert powerful and broad control over the regulation of homeostasis in animals. Secreted hormones play significant roles in...
The endocrine and neuroendocrine systems exert powerful and broad control over the regulation of homeostasis in animals. Secreted hormones play significant roles in lifetime-related events such as germ cell development, sexual maturation, development, metamorphosis, aging, feeding, and energy metabolism. Additionally, hormones, particularly sex steroid hormones, are involved in reproduction, including sexual behavior and dimorphism. Changes in body color protect against external enemies, and circadian rhythms direct physiology and behaviors in synchrony with light and dark cycles. Water and electrolyte metabolism are essential for survival in land or seawater. Both aquatic and terrestrial animals have developed a variety of endocrine and neuroendocrine systems that exquisitely manage water and electrolyte metabolism to support survival. In zoological science, many animal species are investigated for their unique life history phenomena, and many researchers bring original and unique research approaches to understand these phenomena. Exploring such a variety of animal species leads to an understanding of diversity and unity, and contributes to the development of comparative endocrinology. This Special Issue contains 15 papers focusing on the endocrine mechanisms involved in the aforementioned life phenomena.
Topics: Animals; Neurosecretory Systems; Aging; Hormones; Electrolytes; Water
PubMed: 38587511
DOI: 10.2108/zsj.41.1 -
Frontiers in Plant Science 2024Antarctic algae are exposed to prolonged periods of extreme darkness due to polar night, and coverage by ice and snow can extend such dark conditions to up to 10 months....
Antarctic algae are exposed to prolonged periods of extreme darkness due to polar night, and coverage by ice and snow can extend such dark conditions to up to 10 months. A major group of microalgae in benthic habitats of Antarctica are diatoms, which are key primary producers in these regions. However, the effects of extremely prolonged dark exposure on their photosynthesis, cellular ultrastructure, and cell integrity remain unknown. Here we show that five strains of Antarctic benthic diatoms exhibit an active photosynthetic apparatus despite 10 months of dark-exposure. This was shown by a steady effective quantum yield of photosystem II (Y[II]) upon light exposure for up to 2.5 months, suggesting that Antarctic diatoms do not rely on metabolically inactive resting cells to survive prolonged darkness. While limnic strains performed better than their marine counterparts, Y(II) recovery to values commonly observed in diatoms occurred after 4-5 months of light exposure in all strains, suggesting long recovering times. Dark exposure for 10 months dramatically reduced the chloroplast ultrastructure, thylakoid stacking, and led to a higher proportion of cells with compromised membranes than in light-adapted cells. However, photosynthetic oxygen production was readily measurable after darkness and strong photoinhibition only occurred at high light levels (>800 µmol photons m s). Our data suggest that Antarctic benthic diatoms are well adapted to long dark periods. However, prolonged darkness for several months followed by only few months of light and another dark period may prevent them to regain their full photosynthetic potential due to long recovery times, which might compromise long-term population survival.
PubMed: 38584953
DOI: 10.3389/fpls.2024.1326375