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Insects Feb 2024The oriental armyworm, (Walker), is a well-known nocturnal migratory pest that relies on its exceptional nocturnal vision for navigation during long-distance flights....
The oriental armyworm, (Walker), is a well-known nocturnal migratory pest that relies on its exceptional nocturnal vision for navigation during long-distance flights. In this study, we investigated the ultrastructure of the compound eyes of adult using transmission electron microscopy and quantitatively evaluated adaptational changes in the retina under light and dark conditions. The compound eyes of are superposition eyes with a clear zone. The retina shows remarkable anatomical differences under light and dark adaptation, primarily characterized by distinct patterns of rhabdoms within the clear zone: the rhabdoms are nearly absent under light adaptation, but become more voluminous under dark adaptation. In the distal, middle, and proximal sections of the clear zone, the cross-sectional areas of retinulae and rhabdoms, as well as the rhabdom occupation ratio, are significantly larger under dark adaptation than under light adaptation. Conversely, the opposite trend is observed beneath the clear zone. These results indicate remarkable plasticity in the retina throughout a normal daily cycle, providing a theoretical basis for improving searchlight and ground light trap techniques for the management of this migratory species.
PubMed: 38392554
DOI: 10.3390/insects15020135 -
The Science of the Total Environment Apr 2024Hexachlorocyclohexanes (HCH) belong to the banned pesticides with short-time production and use during the last century. However, the consequences of this short period...
Hexachlorocyclohexanes (HCH) belong to the banned pesticides with short-time production and use during the last century. However, the consequences of this short period are still present as persistent environmental contamination. This study represents the large lab-scale experiment focused on the HCH accumulation and metabolism in selected wetland plants (Juncus effuses, Typha latifolia, Phragmites australis) and trees (Alnus glutinosa) after the exposure to the technical mix of HCH isomers (t-HCH) or δ-HCH at three different concentration. During the three-month exposure, morphological (biomass, height, relative chlorophyll content) and physiological (photosynthetic measurements - photosynthetic rate, stomatal conductance, transpiration and dark transpiration) parameters were measured to assess the HCH effect on plant's growth. The results showed that all selected plant species supported HCH removal from the soil. The total removal efficiency was lower for the t-HCH than for δ-HCH exposure, and the best results were provided by Alnus glutinosa tree. Also, no isomer preference was observed in plants exposed to t-HCH. Most HCH remained accumulated in the root biomass, and mainly α-HCH and δ-HCH were transported to the above-ground parts due to their physicochemical properties. Simultaneously, HCH uptake and metabolization to chlorobenzenes (CB) and chlorophenols (CP) occur. Non-targeted analysis showed that CP could be conjugated to glucose and malonyl in plant tissue, and secondary plant metabolism is affected positively and negatively after exposure to t-HCH depending on plant species and chemical concentration. Luteolin, quercetin and quercetin-3-O-glucoside found common to all species showed quantitative changes due to HCH. Nevertheless, most morphological and physiological parameters were adversely affected without statistical significance. This large-scale study provides information on the fate of HCH in the soil-plant system, the suitability of selected plants and their adaptation to chemical stress for use in the phytoremediation process.
Topics: Hexachlorocyclohexane; Bioaccumulation; Wetlands; Biodegradation, Environmental; Plants; Soil
PubMed: 38387594
DOI: 10.1016/j.scitotenv.2024.171141 -
The Journal of Physical Chemistry. A Mar 2024Luminescent organic semiconducting doublet-spin radicals are unique and emergent optical materials because their fluorescent quantum yields (Φ) are not compromised by...
Luminescent organic semiconducting doublet-spin radicals are unique and emergent optical materials because their fluorescent quantum yields (Φ) are not compromised by the spin-flipping intersystem crossing (ISC) into a dark high-spin state. The multiconfigurational nature of these radicals challenges their electronic structure calculations in the framework of single-reference density functional theory (DFT) and introduces room for method improvement. In the present study, we extended our earlier development of ML-ωPBE [, , 12, 9516-9524], a range-separated hybrid (RSH) exchange-correlation (XC) functional constructed using the (SEML) algorithm, from closed-shell organic semiconducting molecules to doublet-spin organic semiconducting radicals. We assessed its performance for a new test set of 64 doublet-spin radicals from five categories while placing all previously compiled 3926 closed-shell molecules in the new training set. Interestingly, ML-ωPBE agrees with the nonempirical OT-ωPBE functional regarding the prediction of the molecule-dependent range-separation parameter (ω), with a small mean absolute error (MAE) of 0.0197 , but saves the computational cost by 2.46 orders of magnitude. This result demonstrates an outstanding capacity of ML-ωPBE for diverse organic semiconducting species. To further assess the predictive power of ML-ωPBE in experimental observables, we also applied it to evaluate absorption and fluorescence energies ( and ) using linear-response time-dependent DFT (TDDFT), and we compared its behavior with nine popular XC functionals. For most radicals, ML-ωPBE reproduces experimental measurements of and with small MAEs of 0.299 and 0.254 eV, only marginally different from those of OT-ωPBE. Our work illustrates a successful extension of the SEML framework from closed-shell molecules to doublet-spin radicals and will open the venue for calculating optical properties for organic semiconductors using single-reference TDDFT.
PubMed: 38382058
DOI: 10.1021/acs.jpca.3c07437 -
MSystems Mar 2024During their long evolution, anoxygenic phototrophic bacteria have inhabited a wide variety of natural habitats and developed specific strategies to cope with the...
During their long evolution, anoxygenic phototrophic bacteria have inhabited a wide variety of natural habitats and developed specific strategies to cope with the challenges of any particular environment. Expression, assembly, and safe operation of the photosynthetic apparatus must be regulated to prevent reactive oxygen species generation under illumination in the presence of oxygen. Here, we report on the photoheterotrophic sp. strain KRV36, which was isolated from a cold stream in north-western Iceland, 30 km south of the Arctic Circle. In contrast to most aerobic anoxygenic phototrophs, which stop pigment synthesis when illuminated, strain KRV36 maintained its bacteriochlorophyll synthesis even under continuous light. Its cells also contained between 100 and 180 chromatophores, each accommodating photosynthetic complexes that exhibit an unusually large carotenoid absorption spectrum. The expression of photosynthesis genes in dark-adapted cells was transiently downregulated in the first 2 hours exposed to light but recovered to the initial level within 24 hours. An excess of membrane-bound carotenoids as well as high, constitutive expression of oxidative stress response genes provided the required potential for scavenging reactive oxygen species, safeguarding bacteriochlorophyll synthesis and photosystem assembly. The unique cellular architecture and an unusual gene expression pattern represent a specific adaptation that allows the maintenance of anoxygenic phototrophy under arctic conditions characterized by long summer days with relatively low irradiance.IMPORTANCEThe photoheterotrophic bacterium sp. KRV36 was isolated from a cold stream in Iceland. It expresses its photosynthesis genes, synthesizes bacteriochlorophyll, and assembles functional photosynthetic complexes under continuous light in the presence of oxygen. Unraveling the molecular basis of this ability, which is exceptional among aerobic anoxygenic phototrophic species, will help to understand the evolution of bacterial photosynthesis in response to changing environmental conditions. It might also open new possibilities for genetic engineering of biotechnologically relevant phototrophs, with the aim of increasing photosynthetic activity and their tolerance to reactive oxygen species.
Topics: Bacteriochlorophylls; Reactive Oxygen Species; Iceland; Photosynthesis; Photosynthetic Reaction Center Complex Proteins; Bacteria; Oxygen
PubMed: 38376261
DOI: 10.1128/msystems.01311-23 -
Expert Review of Ophthalmology 2024
PubMed: 38370915
DOI: 10.1080/17469899.2023.2287178 -
Journal of Hazardous Materials Apr 2024Bioadsorption, bioaccumulation and biodegradation processes in algae, play an important role in the biomagnification of antibiotics, or other organic pollutants, in...
Bioadsorption, bioaccumulation and biodegradation processes in algae, play an important role in the biomagnification of antibiotics, or other organic pollutants, in aquatic food chains. In this study, the bioadsorption, bioaccumulation and biodegradation of norfloxacin [NFX], sulfamethazine [SMZ] and roxithromycin [RTM]) is investigated using a series of culture experiments. Chlorella vulgaris was exposed to these antibiotics with incubation periods of 24, 72, 120 and 168 h. Results show the bioadsorption concentration of antibiotics in extracellular matter increases with increasing alkaline phosphatase activity (AKP/ALP). The bioaccumulation concentrations of NFX, SMZ and RTM within cells significantly increase after early exposure, and subsequently decrease. There is a significant positive antibiotics correlation to superoxide dismutase (SOD), the photosynthetic electron transport rate (ETR) and maximum fluorescence after dark adaptation (F/F), while showing a negative correlation to malondialdehyde (MDA). The biodegradation percentages (P) of NFX, SMZ and RTM range from 39.3 - 97.2, 41.3 - 90.5, and 9.3 - 99.9, respectively, and significantly increase with increasing F/F density and chlorophyll-a. The accumulation of antibiotics in extracellular and intracellular substances of C. vulgaris is affected by antibiotic biodegradation processes associated with cell physiological state. The results succinctly explain relationships between algal growth during antibiotics exposure and the bioadsorption and bioaccumulation of these antibiotics in cell walls and cell matter. The findings draw an insightful understanding of the accumulation of antibiotics in algae and provide a scientific basis for the better utilization of algae treatment technology in antibiotic contaminated wastewaters. Under low dose exposures, the biomagnification of antibiotics in algae is affected by bioadsorption, bioaccumulation and biodegradation.
Topics: Anti-Bacterial Agents; Chlorella vulgaris; Bioaccumulation; Water Pollutants, Chemical; Biodegradation, Environmental; Norfloxacin; Roxithromycin
PubMed: 38364579
DOI: 10.1016/j.jhazmat.2024.133787 -
Ophthalmic & Physiological Optics : the... May 2024To explore the mechanisms of cone sensitivity loss in retinitis pigmentosa by combining two-colour perimetry with threshold versus intensity (tvi) testing.
PURPOSE
To explore the mechanisms of cone sensitivity loss in retinitis pigmentosa by combining two-colour perimetry with threshold versus intensity (tvi) testing.
METHODS
Seven subjects with autosomal recessive retinitis pigmentosa and 10 normal subjects were recruited and underwent perimetric testing of one eye using 480- and 640-nm Goldman size V targets presented under scotopic conditions (no background illumination) and against a white background ranging in luminance from -1.5 to 2 log cd m in 0.5 log cd m steps. Data were fitted with tvi functions of the form logT = logT + log ((A + A)/A), where T is the threshold, T is the absolute threshold, A is the background intensity, A is the 'dark-light' constant and n is a gain constant.
RESULTS
Reliable tvi functions could not be obtained within the region of the visual field corresponding to loss of the ellipsoid zone on optical coherence tomography. At fixation, changes in both T and A were observed, consistent with a d mechanism loss, which resulted in an upwards and rightwards shift of the tvi function. Losses at [±3°, ±3°] demonstrated changes in T, consistent with a d mechanism loss, resulting in an upwards translation of the tvi curve.
CONCLUSIONS
Although the absolute cone threshold was elevated at each location, shifts in the tvi function (so-called d mechanism loss) at fixation minimise threshold elevation in the presence of white adapting backgrounds, such as those typically employed in standard two-colour perimetry. At more peripheral testing locations, changes in threshold occurred independent of background luminance (so-called d mechanism loss). These findings suggest that backgrounds which selectively adapt rods while maintaining cones at, or near, absolute threshold may be preferable to conventional two-colour perimetry for assessing loss of cone sensitivity, especially at the point of fixation.
Topics: Humans; Dark Adaptation; Retinal Cone Photoreceptor Cells; Retinitis Pigmentosa; Visual Fields; Vision, Ocular; Visual Field Tests; Electroretinography
PubMed: 38351866
DOI: 10.1111/opo.13280 -
PloS One 2024Sudden changes in sound and light (e.g., sirens and flashing police beacons) are a common component of working dogs' on-duty environment. Yet, how such stimuli impact...
Sudden changes in sound and light (e.g., sirens and flashing police beacons) are a common component of working dogs' on-duty environment. Yet, how such stimuli impact dogs' ability to perform physical and cognitive tasks has not been explored. To address this shortcoming, we compared the accuracy and time taken for twelve dogs to complete a complex physical and cognitive task, before, during and after exposure to three 'real-world' stimuli: an acoustic distractor (85dB), white strobe lighting (5, 10 & 15 Hz), and exposure to a dazzling white, red, or blue lights. We found that strobe lighting, and to a greater extent, acoustic distraction, significantly reduced dogs' physical performance. Acoustic distraction also tended to impair dogs' cognitive performance. Dazzling lights had no effect on task performance. Most (nine out of twelve) dogs sensitised to the acoustic distraction to the extent of non-participation in the rewarded task. Our results suggest that without effective distractor response training, sudden changes in noise and flickering lights are likely to impede cognitive and physical task performance in working dogs. Repeated uncontrolled exposure may also amplify these effects.
Topics: Animals; Dogs; Lighting; Working Dogs; Dark Adaptation; Task Performance and Analysis; Acoustics
PubMed: 38330038
DOI: 10.1371/journal.pone.0295429 -
Plant Physiology May 2024Measurements of respiratory properties have often been made at a single time point either during daytime using dark-adapted leaves or during nighttime. The influence of...
Measurements of respiratory properties have often been made at a single time point either during daytime using dark-adapted leaves or during nighttime. The influence of the day-night cycle on respiratory metabolism has received less attention but is crucial to understand photosynthesis and photorespiration. Here, we examined how CO2- and O2-based rates of leaf dark respiration (Rdark) differed between midday (after 30-min dark adaptation) and midnight in 8 C3 and C4 grasses. We used these data to calculate the respiratory quotient (RQ; ratio of CO2 release to O2 uptake), and assessed relationships between Rdark and leaf metabolome. Rdark was higher at midday than midnight, especially in C4 species. The day-night difference in Rdark was more evident when expressed on a CO2 than O2 basis, with the RQ being higher at midday than midnight in all species, except in rice (Oryza sativa). Metabolomic analyses showed little correlation of Rdark or RQ with leaf carbohydrates (sucrose, glucose, fructose, or starch) but strong multivariate relationships with other metabolites. The results suggest that rates of Rdark and differences in RQ were determined by several concurrent CO2-producing and O2-consuming metabolic pathways, not only the tricarboxylic acid cycle (organic acids utilization) but also the pentose phosphate pathway, galactose metabolism, and secondary metabolism. As such, Rdark was time-, type- (C3/C4) and species-dependent, due to the use of different substrates.
Topics: Plant Leaves; Poaceae; Cell Respiration; Carbon Dioxide; Photosynthesis; Darkness; Oxygen; Metabolome
PubMed: 38324704
DOI: 10.1093/plphys/kiae064 -
Scientific Reports Feb 2024This study aimed to investigate how the extent and central/peripheral location of the residual visual field (VF) in patients with late-stage inherited retinal diseases... (Review)
Review
This study aimed to investigate how the extent and central/peripheral location of the residual visual field (VF) in patients with late-stage inherited retinal diseases (IRDs) are related to retinal sensitivity detected using full-field stimulus testing (FST). We reviewed the results of Goldmann perimetry and FST from the medical records of patients with IRDs whose VF represents central (within 10°) and/or peripheral islands, or undetectable. In total, 19 patients (19 eyes) were analyzed in this study. The median value of residual VF area was 1.38%. The median values of rod and cone sensitivities were - 14.9 dB and 7.4 dB, respectively. Patients with only the peripheral island (- 33.9 dB) had better median rod sensitivity than other groups (only central, - 18.9 dB; both, - 3.6 dB). VF area significantly correlated with rod sensitivity (r = - 0.943, p = 0.005) in patients with only peripheral island, but not with cone sensitivity. Peripheral VF islands were significant contributors to FST results, especially rod sensitivity. With reduced or loss of central vision, the extent of residual peripheral VF significantly affected rod sensitivity, suggesting that FST can be useful in quantitatively estimating the overall remaining vision in patients with late-stage IRD.
Topics: Humans; Visual Fields; Visual Field Tests; Dark Adaptation; Retina; Retinal Degeneration
PubMed: 38307956
DOI: 10.1038/s41598-024-53474-6