Orange Light Research Articles

Embryonic development of the blenny Parablennius marmoreus (Osteichthyes: Blenniidae)

The fish Parablennius marmoreus (Blenniidae) exhibits demersal spawning characterized by eggs adhering to solid surfaces and male parental care. This research describes the embryonic development under laboratory conditions of 12 spawns obtained in captivity at temperatures ranging from 27 ºC to 30 ºC. The first cell division (2 blastomeres) was observed at 50 minutes post-fertilization (PF). The eggs are smooth, light orange in color, with differentiated violet chromatophores. The chorion diameter measures 0.62±0.06 mm, and the granular yolk has a diameter of 0.45 ±0.08 mm. The blastula stage occurred at 11 hours and 40 minutes PF, and gastrula at 21 hours and 10 minutes PF. Embryo formation took place at 48 hours PF, and the larvae hatched at 135 hours PF, measuring 2.91±0.34 mm in length with a notochord and displaying 97 beats per minute. The captive reproduction and embryonic development of the blenny P. marmoreus are feasible and offer a solution to contribute to the conservation of species with ornamental interest.

A white light emitting reconfigurable pyrazoline-naphthalimide logic gate with magnesium, sodium and proton inputs.

A 3-pyrazolinyl-naphthalimide with a benzo-15-crown-5 receptor operates as a wavelength-reconfigurable dual-output logic gate. Excited with 365 nm light, Na+ and Mg2+ are detected by orange and white light emission, respectively.

Nitrogen-doped orange emitting carbon dots for β-carotene detection and lysosomal imaging.

β-Carotene is a natural antioxidant that has an indispensable effect on the growth and immunity of the human body. For intracellular and in vitro detection of β-carotene, N-doped carbon quantum dots (O-CDs) were prepared by co-heating carbonization of 1,5-naphthalenediamine and nitric acid in ethanol solvent for 2 h at 200 °C. O-CDs have longer wavelength orange light emission, with an optimal excitation peak of 470 nm and an optimal emission peak of 590 nm. According to the principle of the internal filtering effect on which the detection system is based, O-CDs present a good linear relationship with β-carotene within a wide range of 0-2000 μM, and the R2 coefficient of the linear regression equation is 0.999. In addition, O-CDs showed targeting of lysosomes in cell imaging and could be used to detect intracellular lysosomal movement. These experiments show that O-CDs can be used for in vivo and in vitro detection of β-carotene and can serve as a potential substitute to commercial lysosome targeting probes.

Switchable biexcitons in perovskite-like RbCu2Br3 crystals driven by thermally induced phase transition

We report, for the first time, the growth of RbCu2Br3 crystals and investigate their macroscopic transition from blue light emission to dazzling orange light due to thermally induced phase transition.

Continuous synthesis of all-inorganic low-dimensional bismuth-based metal halides Cs4MnBi2Cl12 from reversible precursors Cs3BiCl6 and Cs3Bi2Cl9 under phase engineering

Continuous synthesis of all-inorganic, low-dimensional, bismuth-based metal halides Cs4MnBi2Cl12 with high PLQY from reversible precursors Cs3BiCl6 and Cs3Bi2Cl9 under phase engineering and application of an orange light source.

First report of Neopestalotiopsis clavispora causing leaf spot disease on banana (Musa acuminate L.) in China.

Banana (Musa acuminate L.) is an important tropical fruit in China. In October 2020, a new leaf spot disease was observed on banana plants at an orchard of Zhenkang county (23°45'23.46″ N, 98°48'46.52″ E), Lincang city, Yunnan province, China. The disease incidence was about 1%. The leaf spots occurred sporadically and the percentage of the leaf area covered by lesions was less than 5%. Symptoms on the leaves were initially small, irregular, reddish-brown spots that gradually expanded to fusiform-shaped lesions with a yellow halo and eventually become necrotic, dry, and cracked. To isolate the pathogen, thirty symptomatic leaves (15 mm2) from five plants were surface disinfected in 70% ethanol (10 s) and 0.8% NaClO (2 min), rinsed in sterile water three times, and transferred to potato dextrose agar (PDA) at 28°C for 5 days. Twenty-five colonies formed on the PDA plates were white with cottony aerial mycelium, round with a light orange underside. Abundant black globular acervuli semi-immersed on PDA were observed after a week. Conidia were straight or slightly curved, clavate to spindle, five cells, four septa with dimensions of 17.49 to 34.51 µm × 4.24 to 7.28 µm (avg. 23.83 × 5.62 µm; n=50). The apical and basal cells were hyaline, whereas the three median cells were dark brown. Conidia had a single basal appendage with lengths of 2.95 to 17.7 µm (avg. 7.18 µm; n=50) and two to three apical appendages with lengths of 10.7 to 53.84 µm (avg. 17.36 µm; n=50). These morphological characteristics are consistent with those of Neopestalotiopsis spp. (Maharachchikumbura et al. 2014). To confirm species, single-spore cultures of two representative isolates CATAS-102001 and CATAS-102002 were selected for further identification. The internal transcribed spacer (ITS) region, translation elongation factor 1-α (TEF1-α) and β-tubulin (TUB2) genes of the two isolates were amplified with primers ITS1/ITS4 (White et al. 1990), EF1-728/EF2 (O'Donnell et al. 1998; Carbone and Kohn, 1999) and T1/Bt2b (Glass and Donaldson, 1995; O'Donnell and Cigelnik, 1997), respectively, and sequenced. The sequences were deposited in GenBank (ITS: OM281005 and OM281006; TEF1-α: OM328820 and OM328821; TUB2: OM328818 and OM328819). A maximum likelihood phylogenetic tree was constructed using the MEGA 7.0 (Kumar et al. 2016) based on the concatenated sequences ITS region, EF1-α and TUB2 gene, and the cluster analysis placed the representative isolates CATAS-102001 and CATAS-102002 within a clade comprising Neopestalotiopsis clavispora. The pathogenicity of two isolates was conducted on six 7-leaf-old banana seedlings. Two leaves from each potted plants were stab inoculated by puncturing into 1-mm using a sterilized needle, and stabbing three points at both sides of leaf midrib, and then placing 10 μl conidial suspension (1×106 conidia/ml) on one side of wounded points and the other side of wounded points were inoculated with sterile water as control. Inoculated plants were kept inside a plastic bag for 72 h and maintained in the greenhouse (12 h/12 h light/dark, 28°C, 90% relative humidity). The experiments were repeated twice. Irregular necrotic lesions on inoculated leaves appeared 7 days after inoculation, whereas controls were asymptomatic. The fungus was recovered from inoculated leaves, and its taxonomy was confirmed morphologically and molecularly, fulfilling Koch's postulates. Neopestalotiopsis clavispora has been reported to cause leaf spot on Mangifera indica (Shu et al. 2020), Macadamia integrifolia (Santos et al. 2019) and Ligustrum lucidum (Chen et al. 2020). To our knowledge, this is the first report of N. clavispora on banana in China. The identification of N. clavispora as the causal agent of the observed leaf spot disease on banana is critical to the prevention and control of this disease in the future.

A New Species of Ptilothyris Walsingham (Lepidoptera: Lecithoceridae: Torodorinae) from Nigeria

Since Ptylothyris purpurea Walsingham, 1897 of the family Lecithoceridae was described from Nigeria, no additional species of the family has been known. As the second species of the genus Ptilothyris Walsingham reported from Nigeria, P. medleri Park, sp. nov. is described, based on a single male. The new species can be distinguished from P. purpurea by the antenna light orange throughout and the hind wing lacking orange-white patch.

Morphological Characteristics and Molecular Evidence Reveal four New Species of Russula subg. Brevipedum from China.

In this study, four new species of Russula subg. Brevipedum collected from China are described based on morphological characteristics and molecular evidence. Russula brevispora has a white body whose whole parts often stain brownish-orange or grayish-orange, extremely crowded lamellae with the presence of lamellulae, basidiospores with low warts and an inamyloid suprahilar spot, and clavate or lageniform hymenial cystidia often with a papillary or submoniliform appendage. Russula flavescens is characterized by a white pileus often turning yellowish brown when touched, white lamellae turning brown or light orange, basidiospores with an inamyloid suprahilar spot, and fusiform hymenial cystidia often with an appendage. Russula longicollis is morphologically characterized by a white pileus, turning grayish orange when bruised, white lamellae turning pale yellow when bruised, basidiospores with isolated warts and an amyloid suprahilar spot, and fusiform hymenial cystidia usually with a long appendage. Russula pseudojaponica has a yellowish-brown pileus center, yellowish lamellae unchanging when bruised, basidiospores with low warts and an inamyloid suprahilar spot, clavate hymenial cystidia often with a papillary appendage, and clavate pileocystidia with granulose contents. Phylogenetic analyses showed that R. flavescens, R. brevispora, and R. pseudojaponica are members of the subsect. Pallidosporinae, whereas R. longicollis belongs to subsect. Lactarioideae, and is somewhat related to R. leucocarpa.

First report of Fusarium equiseti causing leaf spots of Bitter gourd (Momordica charantia) in Pakistan.

Bitter gourd (Momordica charantia L.) is an important vegetable crop of the Cucurbitaceae family widely cultivated in Pakistan and around the world. In October 2020, a nutrition management trial of Bitter gourd cv. Seminis-200) was conducted on an area of 10,860 sq. ft. (99×110 feet) at the Agricultural Research farm of Bahauddin Zakariya University, Multan (30.2601° N, 71.5158° E), Pakistan. Symptoms of large, brown necrotic leaf spots were observed on the leaves of bitter gourd vines. The disease started from the yellowing of leaves within the reticulate venation and turned brown. Irregular brown leaf spots coalesced to form large necrotic areas followed by foliar chlorosis then wilting that occurred very late. There were no crown rot symptoms although there was slight discoloration of roots and when cut longitudinally, browning of tissues was observed. The disease was assessed visually with 37% incidence which resulted in poor quality and yield in terms of reduced size and yellowing of fruit. Infected vines along with the roots were collected for the isolation of pathogen. A total of 34 leaves and 22 root samples were collected from the field for isolation. The leaf, collar and root portions were cut into 0.5 to 1 cm in length and surface disinfected with 1% sodium hypochlorite (NaOCl) for 2-3 minutes followed by washing twice with autoclaved distilled water and after drying, placed on potato dextrose agar (PDA) medium, and incubated at 25±2 °C for one week. The fungal colonies of fluffy white growth with light orange pigment were isolated. For morphological characterization, a total of 4 pure cultures were isolated from leaves, collar region and root by single spore technique on carnation leaf agar (CLA) medium after 15 days of incubation at 25±2℃. Curved and thick-walled macroconidia with elongated or pointed apical characteristic foot-shaped basal cells were produced in sporodochia. Macroconidia with 5-7 septa measured 22.50-41.80 μm × 2.90-4.20 μm (n = 60). Thick, brown with roughened walls and subglobose ellipsoidal chlamydospores were observed in clumps or chains with the dimension of 5.8 to 10.8 μm (n = 20). On morphological characteristics, the fungus was identified as Fusarium equiseti (Corda) Sacc. according to Leslie and Summerell (2006). Two single spore isolates were used for molecular identification by amplifying ribosomal DNA of the internal transcribed spacer (ITS) region with ITS1/ITS4 primers (White et al. 1990) and for β-tubulin gene region, primers T1/Bt-2b (O'Donnell and Cigelnik, 1997) were used. The obtained sequences were deposited in GenBank with accession numbers MW880179 and MW880198 from the ITS region and BLAST search in GenBank showed 100 and 98.11% alignment with previously published sequences of F. equiseti with accessions OM992323.1and MT558569.1 respectively. Accession number OM867571from the β-tubulin region showed 100% sequence similarity with F. equiseti with accession MN653163.1. For pathogenicity, macroconidia from 2-week-old cultures on CLA medium were harvested to prepare spore suspension (1 × 106 conidia/ml). Koch's postulates were confirmed on nine bitter gourd plants (cv. Seminis-200) by applying spore suspension of fungal inoculum at 3-4 leaf stage separately on leaves by automizer, on collar region after making incision spore suspension was applied and in the root zone, 20ml spore suspension was added whereas distilled water was used as a control with three replications. Plants were kept under controlled conditions in the greenhouse with 65% to 75% humidity and the temperature was maintained at 32±2 °C for one week. After 7-8 days, inoculated plants began to exhibit symptoms of brown, necrotic leaf spots on the leaves of bitter gourd vines followed by yellowing of leaves that eventually turned brown. Roots showed slight discoloration and browning of vascular bundles and finally, the plants wilted after four weeks. while control plants remained symptomless. The symptoms resembled those noticed in the field. The fungus was re-isolated from leaves, collar region and roots, followed by morphological identification, and finally confirmed as F. equiseti. To the best of our knowledge, this is the first report of a leaf spot caused by F. equiseti in a bitter gourd from Pakistan. If the disease is not managed properly, it may cause a drastic effect on yield under favorable environmental conditions. The pathogen may also damage other cucurbitaceous crops cultivated in the area.

Photons and photocatalysts as limiting reagents for PET-RAFT photopolymerization

The kinetics of photoinduced electron/energy transfer - reversible addition fragmentation chain transfer (PET-RAFT) polymerization were investigated using a model system of methyl acrylate (MA) in the presence of trithiocarbonate chain transfer agents and tris(2-phenylpyridine)iridium(III) (Ir(ppy)3) as the photocatalyst. A powerful polymerization through oxygen approach was developed. Efficient PET-RAFT occurred under blue, violet, and green light with catalyst loadings of 10 ppm. Minimal polymerization was observed under orange or red light. Kinetic scaling analysis was developed to evaluate the impact of light intensity, catalyst loading and geometry of both the light source and the reaction vessel. A universal scaling law was developed for Ir(ppy)3 and other energy transfer catalyzed PET-RAFT, allowing both polymerization through oxygen and deoxygenated systems from the literature to be described across a range of light intensities, reaction conditions and geometries. Finally, the scaling analysis indicates that PET-RAFT systems should be subject to less retardation than conventional RAFT systems, due to the chain transfer agent being involved in radical generation steps.

Structural and luminescent characteristics of orthorhombic GdAlO3:Sm3+ nanocrystalline materials for solid state lighting

In the current article, an eco-friendly, efficient and less energy consuming gel-combustion process has been used to develop a series of perovskite based Gd1-xAlO3:xSm3+ (x = 0.01, 0.03, 0.05, 0.07 and 0.09 mol) nanomaterials which produce reddish orange light. According to crystallographic investigation, the synthesized nanocrystalline materials belong to orthorhombic crystal symmetry having space group Pnma (62). The non-uniform agglomerated particles in nano range (35–45 nm) were examined via TEM analysis, which supports the results obtained from XRD analysis. The PL spectra involve 4f-transitions of trivalent samarium ions, such as 4G5/2→ 6H5/2 (565 nm), 4G5/2→ 6H7/2 (601 nm) and 4G5/2 → 6H9/2 (647 nm). The energy transferal mechanism between neighbouring trivalent samarium ions is dipole–dipole (DD) interaction, which is answerable for the quenching of luminous intensity. Additionally, colorimetric characteristics like color coordinates, color-purity and correlated-color temperature were obtained using PL data. These photometric parameters were strongly recommends these synthesized nanophosphors samples for solid state lighting applications.

Fire Detection using Image Processing

To reduce loss of life and property from fire, an early warning is an imperative. A fire detection system based on light detection and analysis is proposed in the paper. This system uses HSV and YCbCr color models with given conditions to separate orange, yellow, and high brightness light from background and ambient light. Fire growth is analysed and calculated based on frame differences. The overall accuracy from the experiments has been greater than 90%.

Characterisation of pupillary responses to alternating blue and orange light exposures in a fMRI protocol

AbstractBackgroundThe non‐image forming (NIF) functions of light are diverse and include stimulation of cognition and alertness, sleep regulation and pupil diameter modulation. Previous work indicated that exposure to blue‐enriched light as well as pupil size variations are associated with higher locus coeruleus (LC) activity. Given the central role of LC structure and function in the earliest stages of Alzheimer’s disease neuropathology, light exposure may constitute a promising stimulation technique to delay disease progression. Prior to addressing light impact on the LC, here, we aimed at characterising the pupil responses to light during fMRI protocol, to determine its quality in assessing NIF effects of light.MethodPupil diameter was continuously recorded in 11 healthy subjects (20‐30yr, 7 women) with an infrared eyetracker device while they were administered a 15‐min auditory oddball task in a 7T MRI scanner. Participants were concomitantly exposed to pseudo‐randomly alternating 30s blocks of blue‐enriched (4,000K; 200µW/cm2) and orange (589nm; 6x1013photons/cm2/s) lights. Statistics consisted in generalized linear mixed models seeking effects of light condition on pupil response, with subjects as random intercept and controlling for age, sex and BMI.ResultBlue light condition was associated with a significantly smaller pupil diameter as compared to the orange condition, (main effect of light condition: F(2,270)=571.22;p<.0001; Fig1). Moreover, the impact of the light condition on pupil size did not significantly change over the 15min‐protocol (light condition x block repetition interaction: F(12,240)=1.21 ; p=.28), suggesting that time‐in‐protocol and prior light blocks did not influence pupil constriction.ConclusionWe report preliminary results confirming that blue‐enriched light triggers a stronger pupil response than longer wavelength light and showing that the protocol induces a stable response in time even when using short alternating light exposures. These findings support the validity of the protocol to assess NIF responses to light in fMRI in healthy participants, including over the LC. Being able to stimulate the LC holds important implications for possibly delaying Alzheimer’s disease progression. We now aim to include more participants, including older individuals, and to extend to other cognitive tasks to assess the generalization of the present findings to other cognitive domains and age‐ranges.

Structural and luminescence property evaluation of Sm3+ activated orange light emitting Li7La3Zr2O12 phosphors

• Synthesis of cubic blue light emitting pure LLZO and orange light emitting LLZO: xSm 3+ (x=0.1, 0.3, 0.5, 0.7 and 0.9 M.W%) phosphors by solid state reaction method. • The optical energy band gap values of synthesised phosphors for pure and Sm 3+ doped LLZO were calculated to be 4.140 eV and 3.972 eV, respectively. • The strongest PL emission band observed at 602 nm was assigned to 4 G 5/2 → 6 H 7/2 transition in orange region under the ultraviolet excitation wavelength of 408 nm. • The blue and orange light emission was confirmed by CIE chromaticity X, Y coordinates. • Color purity and CCT value of 0.5 MW% Sm 3+ doped LLZO phosphor was 85.9% and 2227 K, respectively. Samarium (Sm) activated Li 7 La 3 Zr 2 O 12 (LLZO) phosphors were synthesized by solid state reaction method. Crystal structure of Sm 3+ doped LLZO was investigated using X-ray diffraction and Raman spectroscopy analysis. From Raman spectra, the presence of characteristic Raman peak at 110 cm -1 confirms the formation of LLZO. The Raman peaks present at 345 cm -1 and 125 cm -1 correspond to T 2g Raman mode of vibration and E g mode of vibration, respectively. The optical energy band gap values of synthesised phosphors obtained from UV-Vis spectroscopy for pure and Sm 3+ doped LLZO were calculated to be 4.140 eV and 3.972 eV, respectively. Microstructure and selected area diffraction (SAED) pattern of phosphor was observed by High Resolution Transmission Emission Electron Microscope. Using an excitation wave length of 209 nm,blue emission was observed for pure LLZO and the chromaticity coordinate was found to be at (x=0.1636, y=0.0123). Sm 3+ doped phosphors showed orange light emission under 408 nm excitation due to transition of 4 G 5/2 - 6 H 7/2. as observed from the Commission Internationale de l’Eclairage (CIE) chromatic coordinate graph. The maximum intensity of emission was observed in 0.5% Sm 3+ doped LLZO with the calculated color purity and correlated color temperature of 85.9% and 2229k, respectively.

Luminescence properties and thermal stability of Sm3+-doped Na2O–Y2O3–SiO2–P2O5 transparent glass-ceramics containing Na3YSi2O7 crystals

Sm3+-doped Na2O–Y2O3–SiO2–P2O5 precursor glasses were prepared by melting cooling and quenching methods. The optimal doping concentration of Sm3+ ions was determined by fluorescence spectrum. The thermodynamic parameters of precursor glass were determined by the DSC test. The transparent glass-ceramics containing Na3YSi2O7 crystals were obtained by proper heat treatment. The types and microstructures of Na3YSi2O7 crystals were characterized by XRD and SEM. The highest emission peak in the emission spectrum represents the transition of Sm3+: 6H5/2 → 4F7/2. Moreover, the emission intensity of the glass-ceramic is 3 times higher than the original. According to the calculation results of CIE chromaticity coordinates, the luminescence of the glass-ceramics and precursor glass were located in the orange light region. The high thermal stability of the glass-ceramic was discussed through the variable temperature fluorescence test. The thermal quenching activation energy was determined to be 0.27 eV. The results indicate that the transparent glass-ceramics containing Na3YSi2O7 crystals have potential applications in orange LED components.

Synthesis, photoluminescent properties, and an insight into the Judd-Ofelt analysis of the NaPbBi(2-x)(PO4)3: xEu3+ orthophosphate phosphors for light applications

A set of novel reddish orange light emitting NaPbBi2(PO4)3: xEu3+ (hereafter referred to as NPbBP) phosphate phosphors were synthesized by the conventional solid state reaction route. The phase formation, particle morphology, elemental composition and the optical properties of the prepared phosphors were studied in detail from the powder XRD data, SEM images, EDS analysis, and the diffuse reflectance spectroscopy measurements respectively. The photoluminescence properties were systematically studied by recording the excitation and emission spectra of the prepared phosphors. The NPbBP: xEu3+ phosphors, excited at the near ultraviolet light, exhibited the reddish orange light emission in the visible region due to the dominance of magnetic dipole transition of the Eu3+ ions in the host. The details of the radiative properties were analyzed through the Judd- Ofelt intensity parameters, which were found to follow the trend of Ω2< Ω4. The thermal stability and the life time of the phosphors were investigated. The calculated photometric parameters of the NPbBP: 0.09Eu3+ phosphor suggested that the emission was found in the reddish-orange region with a high color purity and high quantum yield of 99.53% and 79.7% respectively. These results showed that the NPbBP: Eu3+ phosphor could serve as a good phosphor for use in various optoelectronic devices such as phosphor converted WLEDs, solar cells, and display panels.

Characterization of Algerian apricots (Prunus armeniaca) using morphological and pomological markers

The aim of this study was to evaluate the diversity of an Algerian apricot germplasm. This Algerian apricot was characterized by a green-yellow skin, a red ground color, and a light orange flesh color in general. Besides, highly positive and negative significant correlations were revealed between the studied characters. Whereby, the principal component analysis explained 81% of the variability. Fruit, stone and leaves dimensions were the main features that explained evidentially the majority of variability. Moreover, the cluster analysis divided the accessions into two major groups. Thus, Algerian accessions selected in this study may have the potential to be used in apricot breeding programs in the future.

Light response of Vibrio parahaemolyticus

Light is one of the most critical stimuli in the majority of living organisms. In the last two decades, blue light (BL) has become a major subject of attention because of developments in light-emitting diodes (LED). The effects of BL on eukaryotic organisms and phototrophic prokaryotes have been well studied, but the knowledge of its effects on non-phototrophic prokaryotes remains unclear. Since BL can penetrate seawater, it is expected that most prokaryotes living in the ocean possess molecular mechanisms which protect against BL. The aim of this study is to assess the molecular mechanisms of Vibrio parahaemolyticus cells against BL as a marine bacterial model compared to other wavelength light exposures. Physiological and transcriptomic analyses of BL-exposed cells compared to other light treated cells revealed the highest ROS fold change, the highest number of differentially expressed genes (DEGs), and up-regulation in the gene responsible to not only compatible solute such as glycine betaine and ectoine but also iron-sulfur biosynthesis related to ROS formation. Furthermore, red light (RL) up-regulated the expression of cryptochrome DASH, a protein known to be excited by BL, and orange light (OL) decreased the expression of thermostable direct hemolysin (TDH), suggesting that OL attenuates the virulence of V. parahaemolyticus. In addition, the expression of VtrA (V. parahaemolyticus type III secretion system 2 (T3SS2) regulator A) but not VtrB (V. parahaemolyticus T3SS2 regulator B) increased under both light treatments, indicating that light exposure is unlikely to be involved in T3SS2-mediated pathogenicity. These results expand our knowledge on unique light responses in non-phototrophic marine prokaryotes.

Investigating the effects of low intensity visible light on human keratinocytes using a customized LED exposure system

Photobiomodulation (PBM) refers to the use of light to modulate cellular processes, and has demonstrated utility in improving wound healing outcomes, and reducing pain and inflammation. Despite the potential benefits of PBM, the precise molecular mechanisms through which it influences cell behavior are not yet well understood. Inconsistent reporting of key light parameters has created uncertainty around optimal exposure profiles. In addition, very low intensities of light, < 0.1 J/cm2, have not been thoroughly examined for their use in PBM. Here, we present a custom-made compact, and modular LED-based exposure system for studying the effects of very low-intensity visible light (cell proliferation, migration, ROS production, and mitochondrial membrane potential) of three different wavelengths in a parallel manner. The device allows for six repeats of three different exposure conditions plus a non-irradiated control on a single 24-well plate. The immortalised human keratinocyte cell line, HaCaT, was selected as a major cellular component of the skin epidermal barrier. Furthermore, an in vitro wound model was developed by allowing the HaCaT to form a confluent monolayer, then scratching the cells with a pipette tip to form a wound. Cells were exposed to yellow (585 nm, 0.09 mW, ~ 3.7 mJ/cm2), orange (610 nm, 0.8 mW, ~ 31 mJ/cm2), and red (660 nm, 0.8 mW, ~ 31 mJ/cm2) light for 10 min. 48 h post-irradiation, immunohistochemistry was performed to evaluate cell viability, proliferation, ROS production, and mitochondrial membrane potential. The results demonstrate increased proliferation and decreased scratch area for all exposure conditions, however only red light increased the mitochondrial activity. Oxidative stress levels did not increase for any of the exposures. The present exposure system provides opportunities to better understand the complex cellular mechanisms driven by the irradiation of skin cells with visible light.

Patterned Stimulation of the Chrimson Opsin in Glutamatergic Motor Thalamus Neurons Improves Forelimb Akinesia in Parkinsonian Rats

Parkinson’s disease (PD) is a motor disorder charactertised by altered neural activity throughout the basal ganglia-thalamocortical circuit. Electrical deep brain stimulation (DBS) is efficacious in alleviating motor symptoms, but has several notable side-effects, most likely reflecting the non-specific nature of electrical stimulation and/or the brain regions targeted. We determined whether specific optogenetic activation of glutamatergic motor thalamus (Mthal) neurons alleviated forelimb akinesia in a chronic rat model of PD. Parkinsonian rats (unilateral 6-hydroxydopamine injection) were injected with an adeno-associated viral vector (AAV5-CaMKII-Chrimson-GFP) to transduce glutamatergic Mthal neurons with the red-shifted Chrimson opsin. Optogenetic stimulation with orange light at 15 Hz tonic and a physiological pattern, previously recorded from a Mthal neuron in a control rat, significantly increased forelimb use in the reaching test (p < 0.01). Orange light theta burst stimulation, 15 Hz and control reaching patterns significantly reduced akinesia (p < 0.0001) assessed by the step test. In contrast, forelimb use in the cylinder test was unaffected by orange light stimulation with any pattern. Blue light (control) stimulation failed to alter behaviours. Activation of Chrimson using complex patterns in the Mthal may be an alternative treatment to recover movement in PD. These vector and opsin changes are important steps towards translating optogenetic stimulation to humans.