Different Sources Of Light Research Articles

Microtubule‐associated protein tau (MAPT) in the lens of the eye in non‐transgenic and transgenic tau mutant (P301S) mice

AbstractBackgroundWe previously discovered that Aβ accumulates in the cortical/supranuclear region of the lens in people with Alzheimer’s Disease (AD) (Goldstein et al., 2003) and Down Syndrome (DS; (Moncaster et al., 2010). We also demonstrated Aβ in the Tg2576 APP Swedish mutation AD mouse model (Moncaster et al., 2022). Another protein that is involved in AD is Microtubule‐Associated Protein Tau (MAPT). Tau is expressed in the brain and becomes hyperphosphorylated in AD eventually forming neurofibrillary tangles. Tau has previously been reported to be expressed in the mouse lens (Bai et al., 2007; Zhao et al., 2013) but the results vary depending on the mouse model. Here we investigated whether tau protein was expressed in non‐transgenic mouse lenses and in a transgenic tau mutant (P301S) mouse model. We also studied whether cataracts may develop in this P301S tau mutant mouse model.MethodP301S tau mutant transgenic and non‐transgenic mice were bred and maintained at Boston University. Breeder mice were purchased from The Jackson Laboratory, Bar Harbor, ME. Male and Female transgenic and non‐transgenic mice were sacrificed throughout their lifespan at ages 3‐12 months. Mice were perfused with phosphate buffer saline, lenses were isolated and then imaged under two different sources of light using a D70 digital Nikon camera and a custom‐adapted Zeiss stereophotomicroscope. Lenses were then snap frozen and analyzed by Western Blotting using tau antibodies.ResultP301S transgenic and non‐transgenic mouse lenses all expressed tau during their lifespan when analyzed by Western blot. P301S transgenic lenses demonstrated an additional higher molecular weight band compared to the non‐transgenic mice. No cataract phenotype was observed in transgenic or non‐transgenic mouse lenses.ConclusionThere was no overt difference in lens phenotype between the P301S transgenic and non‐transgenic mice. However, the banding pattern observed by Western blot for P301S transgenic mice compared to non‐transgenic was different. Our data suggest the P301S tau mutation affects tau processing but does not result in a cataract phenotype. Based on our current and previous results, the data suggests that Aβ may play a more significant role than tau in lens pathology in AD.

Effectiveness of photodynamic therapy (PDT) in the management of symptomatic oral lichen planus -A systematic review.

Oral Lichen Planus (OLP) is a chronic mucocutaneous inflammatory disease of unknown aetiology characterized by T cell mediated autoimmune response which trigger apoptosis of basal cells of an oral epithelium. Corticosteroids are the primary therapeutic option for symptomatic OLP however treatment of lesions unresponsive to corticosteroids that tend to recur are becoming challenging for the clinicians. Currently photodynamic therapy (PDT) is being explored as a new curative option for reduction of pain and/or burning sensation associated with OLP lesions. The aim of this systematic review was to analyse studies from literature on the therapeutic effectiveness of PDT in management of symptomatic OLP unresponsive to corticosteroid therapy. The electronic retrieval systems and databases PUBMED [MEDLINE], EMBASE, SCOPUS, WEB OF SCIENCE, GOOGLE SCHOLAR, and SCIENCE DIRECT were searched independently by two authors for relevant articles from January 2015 till July 2021. Primary studies focussed on the role of PDT in treatment of symptomatic OLP and published in English were included. Out of the 370 articles, only ten studies met the selection criteria. Included studies demonstrated PDT as an effective alternative modality to treat symptomatic OLP with no drop outs. In all studies, with PDT reduction in lesion size and VAS score was observed during each follow up sessions and after treatment (approx. 12 weeks) when compared to pre-treatment level (p<0.001). Four studies noted PDT to be more effective than topical corticosteroids in reduction of signs and symptoms of OLP (p=0.001). In the future, long-term studies on larger population should be conducted to establish the clinical effectiveness in PDT in symptomatic OLP. Studies should take into consideration different sources of light and photosensitizers to determine the ideal parameters of PDT treatment for OLP. Wavelength is the most important factor in all types of photo therapies, so the most appropriate wavelength should be selected to obtain better outcome.

The reactivity of peroxymonosulfate towards sulfamethoxazole

In this study, an in-depth assessment of the peroxymonosulfate (PMS) reactivity towards sulfamethoxazole (SMX) is reported for the first time based on (i) a comparative kinetics of SMX recorded under different sources of light (simulated solar irradiation and UV-C) and in the dark, all under different operational conditions (PMS and SMX dosages, pHs, temperatures, presence of chloride and hydrogen carbonate ions) and (ii) monitoring the role of Reactive Oxygen Species (ROS) involved in each investigated case with the use of proper scavengers together with the recording of Electron Paramagnetic Resonance spectra. SMX degradation rates obtained in dark, at acid/neutral pH and in presence of selective ROS scavengers demonstrated that SO4•–, 1O2 and HO• played a minor role; while the degradation at different pHs suggested the presence of two operational mechanisms: direct oxidation of the substrate by direct electron transfer between PMS and SMX and indirect oxidation through HO• and 1O2 at basic pH. Moreover, thermal assessment in dark showed that the process followed the Arrhenius equation with an activation energy 36.0 ± 1.6 kJ/mol. Under artificial solar irradiation, the kinetics constant of SMX increased due to the reached temperature and similar results were obtained in the dark at the same temperature. Therefore, the solar light could be discarded as PMS photochemical activation method for ROS generation. On the contrary, SMX degradation activated by the 254 nm PMS photolysis was based on the homolytic cleavage of the O-O bond with the formation of SO4•– and HO• radicals with a ratio 1.2:1. HO• radicals prevails over SO4•– at basic pH where the oxidation of OH– to HO• by SO4•– is strongly favored. The findings obtained in this research stands out the basis of PMS reaction in water and the mechanisms governing the microcontaminants degradation in function of the type of irradiation source and under the most commonly natural occurring inorganic water constituents, demonstrating also the potential application of this oxidant in combination with natural sunlight for water purification.

Phenotyping of lenses from eyes of P301S tau mice

AbstractBackgroundWe previously discovered that Aβ accumulates in the supranuclear region of the lens in the eyes of people with Alzheimer’s Disease (AD) (Goldstein et al., 2003) and Down Syndrome (DS; (Moncaster et al., 2010) and also in the Tg2576 APP swedish mutation AD mouse model (Moncaster et al., 2022). Aβ interacts with crystallin proteins in the lens to create light scattering aggregates that eventually manifest as cortical cataracts. Tau has previously been reported to be expressed in the lens of the eye (Bai et al., 2007; Zhao et al., 2013). Here we investigated whether cataracts may develop in the P301S tau model.MethodP301S mice were bred and maintained at Boston University School of Medicine. Breeder mice were purchased from Jackson Laboratories, Bar Harbor, ME. Male and Female transgenic and non‐transgenic mice (n = 5‐6 per group) were sacrificed at ages 12‐13 months. This timepoint was chosen as it is the limit of lifespan for P301S transgenic mice. Mice were perfused with phosphate buffer saline, lenses were isolated and then imaged under two different sources of light using a D70 digital Nikon camera and a custom‐adapted Zeiss stereophotomicroscope.ResultThere was no overt difference in lens phenotype between the P301S transgenic and non‐transgenic mice. No cataracts were observed in these lenses at 12‐13 months of age.ConclusionThere was no overt difference in lens phenotype between the P301S transgenic and non‐transgenic mice. Based on our current and previous results, the data suggests that Aβ may play a more significant role in lens pathology in AD than tau.

Light at night exposure and risk of depression and other mental disorders: a systematic review

BACKGROUND AND AIM: In modern society, individuals are increasingly exposed to artificial light at night (LAN) i.e., different sources of light altering the natural day-night cycle. Emerging evidence suggests a possible association between LAN exposure and physiological and behavioral changes, with implications on mood and mental health at the population level. We performed a systematic review of observational studies to investigate if LAN exposure, may be associated with an increased risk of mental diseases in humans. METHODS: We reviewed the epidemiological evidence about the association between LAN exposure as assessed either via satellite photometry (outdoor LAN) or via measurements of bedroom brightness (indoor LAN), and risk of mental disorders. We systematically searched the PubMed, Embase and Web of Science databases up to April 1, 2022. Studies were included if they assessed the link between exposure to indoor or outdoor LAN and one or more mental disorders. RESULTS: Nine eligible studies were included in this review: six studies had a cross-sectional design, two had a longitudinal design with a median follow-up of 24 months, and one was a case-cohort study. Studies were published between 2002 and 2022. Seven studies were conducted in adult populations, one in adolescents, and one in children. Mental disorders investigated include anxiety and mood disorders, depression, bipolar disorder and autism. Overall, we found moderate evidence of a positive association between LAN exposure and depressive symptoms and to a lesser extent other mental disorders, though the number of studies was limited and potential residual confounding such as socioeconomic factors, noise, or air pollution may have influenced the results. CONCLUSIONS: Although more robust evidence is needed, the epidemiological evidence produced so far seems to support an association between LAN and risk of depressive disorders. KEYWORDS: mental disorders; light at night; depression; systematic review, environmental risk factors

QED and accretion flow models effect on optical appearance of Euler–Heisenberg black holes

Taking the quantum electrodynamics (QED) effect into account, we investigate the geometrical-optics appearance of the Euler–Heisenberg (EH) black hole (BH) under the different accretion flows context, which depends on the BH space-time structure and different sources of light. The more significant magnetic charge leads to the smaller shadow radius for the EH BH, while the different values of the EH parameter do not ruin it. Different features of the corresponding two-dimensional shadow images are derived for the three optically thin accretion flow models. It is shown that the total observed intensity in the static spherical accretion flow scenario leads than that of the infalling spherical accretion flow under same parameters, but the size and position of the EH BH shadows do not change in both of these accretions flows, implying that the BH shadow size depends on the geometric space-time and the shadows luminosities rely on the accretion flow morphology. Of particular interest is that a thin disk accretion model illuminated the BH, we found that the contribution of the lensing ring to the total observed flux is less than 5%, and the photon ring is less than 2%, indicating that the direct emission dominates the optical appearance of the EH BH. It is also believed that the optical appearance of the BH image depends on the accretion disk radiation position in this scenario, which can serve as a probe for the disk structure around the active galactic nucleus (AGN) of M87^{*} like.

Visible light driven photocatalytic activities of metal sulfides synthesized by simple co-precipitation method

Simple co-precipitation method was employed for the successful preparation of metal sulfide nanostructures (ZnS and CdS). The structural properties of the samples were investigated using X-Ray Diffraction (XRD) technique. The crystallite size of CdS and ZnS were observed to be 3.2 nm and 3.3 nm respectively. The optical properties of the samples were examined using UV–Visible absorbance and FTIR spectroscopy. The elemental composition of the samples were characterized using EDX. The photocatalytic activities of the nanostructures were studied and compared towards the degradation of Malachite green dye under the action of different sources of light. Under visible light source, CdS shows higher photocatalytic efficiency which degrades 95% of the dye as compared to ZnS which degrades only 35% of the dye under 2 h of light irradiation. However, under UV light source, ZnS shows higher photocatalytic efficiency with degradation percentage of 63% as compared to CdS whose degradation percentage is 42% under the same experimental condition.

The effect of natural and artificial light at night on nocturnal song in the diurnal willie wagtail

Artificial light at night (ALAN) has rapidly and drastically changed the global nocturnal environment. Evidence for the effect of ALAN on animal behaviour is mounting and animals are exposed to both point sources of light (street and other surrounding light sources) and broadscale illuminance in the form of skyglow. Research has typically taken a simplified approach to assessing the presence of ALAN, yet to fully understand the ecological impact requires consideration of the different scales and sources of light concurrently. Bird song has previously been well studied for its relationship with light, offering an opportunity to examine the relative impact of different sources of light on behaviour. In this study, we combine correlational and experimental approaches to examine how light at night affects the nocturnal song behaviour of the largely diurnal willie wagtail (Rhipidura leucophrys). Observations of willie wagtails across urban and rural locations in southeastern Australia demonstrated that nocturnal song behaviour increased with the intensity of moonlight in darker rural areas but decreased in areas with high sky glow. In addition, willie wagtails were half as likely to sing at night in the presence of localized light sources such as streetlights in urban and rural areas. Experimental introduction of streetlights to a previously dark area confirmed this relationship: willie wagtail song rates declined when lights were turned on and returned to their original rates following streetlight removal. Our findings show that scale, as well as intensity, are important when considering the impact of light at night as moonlight, sky glow, and localized sources of artificial light have different effects on nocturnal song behaviour.

Co3O4 nanoparticles synthesized from waste Li-ion batteries as photocatalyst for degradation of methyl blue dye

Cobalt oxide nanoparticles were synthesized from waste Li-ion batteries and characterized using XRD, EDX and FE-SEM. The FE-SEM images depict a spherical shape and a particle size of 47 nm for Co 3 O 4 nanoparticles. The band gap energy of the synthesized cobalt oxide particles was evaluated. The synthesized particles were used for the degradation of methyl blue dye (MYB) under different sources of light. The progress of degradation was monitored using UV–Vis spectroscopic analysis. The effect of various experimental parameters such as catalyst loading, initial concentration of methyl blue, pH of the solution and type of light source were systematically studied in order to achieve maximum degradation efficiency. Experiments were also carried out to investigate the recyclability of the Co 3 O 4 particles for photodegradation. Pseudo first-order kinetics was followed for photodegradation of methyl blue. The synthesized Co 3 O 4 catalyst allowed >86 % dye removal within 45 min. under solar light irradiation. • Co 3 O 4 NPs recovered from waste Li-ion battery used for photo degradation. • Methyl blue is degraded efficiently under solar light in presence of Co 3 O 4 NP. • Quantitative degradation of the dye is achieved at neutral pH. • Co 3 O 4 NPs have been successfully recovered and reused. • Product of a waste being used for remediation of environmental contamination.

Limitations of the Schlieren technique for shielding gas flow visualization in arc welding processes

Gas protection is very important in arc welding processes and several factors influence its effectiveness. This paper provides a discussion of the applicability of the Schlieren technique to arc welding processes. Tests were performed with different types of shielding gas and with GMAW and GTAW torches, in order to highlight differences associated with the various conditions. The results obtained in conjunction with a review of results reported in the literature allowed an evaluation of the limitations associated with the use of the Schlieren technique in the arc welding processes. The most important limitation is that the visualization is inherently difficult when using pure Ar gas, meaning that in most situations it is not possible to adequately visualize the flow interface with atmospheric air, which is the main region of interest in this type of analysis. However, visualization is possible in regions where pure Ar is heated, or when mixtures with other gases are used. In addition, the results obtained with different sources of light were compared and the test was performed by filming the arc welding or with the gas flowing through the torch without the arc. The differences observed in the results obtained are discussed herein.

Effects of different sources of light as night break on growth characteristics of Korean chrysanthemum (Chrysanthemum morifolium Ramat.) genotypes

Longer photoperiods in the form of night break (NB) were applied in chrysanthemum to inhibit the flower bud differentiation for regulating the production and supply in the market. The present study reports the effect of three sources of light (Incandescent bulbs, compact fluorescent lights (CFL) and light emitting diodes-LED) as NB treatment on ten genotypes of Korean chrysanthemum for two years i.e. 2015 and 2016. The NB treatment with LED lights resulted in increased internodal length (8.20 and 9.00 mm), partitioning coefficient (30.50 and 31.50), number of stomata per unit area (56.08 and 56.87), anthocyanins (8.99 and 9.16 mg/g) and carotenoids (28.11 and 28.39 mg/g). However, leaf thickness, petiole length, leaf area index, and leaf weight ratio were affected non-significantly. But petiole girth was recorded maximum (1.22 and 1.49 mm) under incandescent bulbs which was at par with LED and significantly higher than CFL.

Impact of warm-up period on optical coordinate measuring machine measurement accuracy

The multisensor optical coordinate measuring machines utilizes various systems used for point coordinates acquisitions. Different sources of light, power supply units and other electric devices along with motors responsible for machine movement along coordinate system axes introduces temperature variation into its measuring volume. It may be especially problematic after turning a machine on as it took some time before temperature of system stabilize. This paper tries to answer if accurate measurements can be performed during machine warm-up period. Applied methodology is based on the measurements of hole plate standard performed during machine warm-up and after a temperature stabilization. Additionally the amount of time needed for the temperature stabilization can be estimated. Obtained results show that although utilized temperature compensation reduce systematic errors related with temperature variations, the warm-up period may introduce the noticeable change of point measurement uncertainty.

Optimization of Materials Composition and UV-VIS Light Wavelength Towards Curing Time Performance on Development of Tissue Engineering Scaffold

VAT photopolymerization 3D printing is a process that solidified a vat of liquid photopolymer resin solution into desired products in the presence of UV light. Achieving an optimal property with shorter curing time is an ultimate goal when using functional or special resins. In this study, the effect of wavelength with different compositions of UHT resin mixed PEG solution is studied. Different sources of light were identified, which is UV-A with a wavelength of 365 nm and VIS with a wavelength greater than 420 nm. The PEGconcentrations were varied at 40%, 50%, and 60%. While UHT concentration ratio added into solution was 30%, 50%, and 70%. It has been observed that the optimum curing under UV and VIS wavelength were 9.55 minutes and 17.48 minutes respectively. The feasible range to optimize results of curing time, PEG 48%and UHT 41% with the result 8.6 minutes for the UV-A. Meanwhile, for VISwavelength, PEG 49% and UHT 64% with the result 16 minutes. The success of this study will lead to further innovation on UV-VIS light source in 3D printing in terms of energy efficiency, safety, and cost as well as further evaluation of the performance with respect to the mechanical properties of tissue engineering scaffold.

Photodegradation of novel brominated flame retardants (NBFRs) in a liquid system: Kinetics and photoproducts

The photolysis of four typical NBFRs decabromodiphenyl ethane (DBDPE), bis(2-ethylhexyl) tetrabromophthalate (TBPH), pentabromotoluene (PBT) and hexabromobenzene (HBB) were first explored under different sources of light, two temperatures, organic solvents and the presence of humic substance (HS). Degradation could be described by pseudo-first-order kinetic model. Under different irradiation sources, the degradation rates were in order of UVC (0.0616–0.137 min−1) > UVB (0.0348–0.0810 min−1) > sunlight (0.0102–0.0370 min−1) > UVA (almost no degradation). Under UVB irradiation, the half-life of NBFRs was the lowest in tetrahydrofuran (6.16–22.77 min), and the longest (93.42–>120 min) in acetone, indicating that organic solvents greatly affected the degradation kinetics. HS could influence the degradation, and DBDPE or TBPH respectively declined 13.92–30.68% and 12.17–59.41% at 240 min, while the degradation of PBT and HBB were highly inhibited. TBPH photolysis was affected by humic acid (HA) or fulvic acid (FA) concentration, but DBDPE degradation barely showed significant difference (p < 0.05) in the presence of 1 and 10 mg L−1 of HA. Photolytic products of the four NBFRs were identified by GC-NCI/EI-MS, indicating that the photodegradation process was mainly stepwise debromination from high- down to low-bromine-substituted NBFRs. 2,4,6-triBT and 2,4,5-triBT were identified as products of PBT. PBB, 1,2,4,5-tetraBB, 1,2,4-triBB, 1,3,5-triBB and 1,3/1,2-diBB were identified as products of HBB. Our observations could provide a few insights into the removal of NBFRs in a liquid environment.

Estimating the relative contribution of streetlights, vehicles, and residential lighting to the urban night sky brightness

Under stable atmospheric conditions the brightness of the urban sky varies throughout the night following the time course of the anthropogenic emissions of light. Different types of artificial light sources (e.g. streetlights, residential, and vehicle lights) have specific time signatures, and this feature makes it possible to estimate the amount of brightness contributed by each of them. Our approach is based on transforming the time representation of the zenithal night sky brightness into a modal expansion in terms of the time signatures of the different sources of light. The modal coefficients, and hence the absolute and relative contributions of each type of source, can be estimated by means of a linear least squares fit. A practical method for determining the time signatures of different contributing sources is also described, based on wide-field time-lapse photometry of the urban nightscape. Our preliminary results suggest that, besides the dominant streetlight contribution, artificial light leaking out of the windows of residential buildings may account for a significant share of the time-varying part of the zenithal night sky brightness at the measurement locations, whilst the contribution of the vehicle lights seems to be significantly smaller.

Aβ-INDEPENDENT AND Aβ-POTENTIATED AGE-RELATED CHANGES IN THE LENS OF WILD-TYPE AND ALZHEIMER’S DISEASE TG2576 MICE

We previously discovered that Aβ accumulates in the supranuclear region of the lens in the eyes of people with Alzheimer's Disease (AD) (Goldstein, Lancet, 2003) and Down Syndrome (DS; (Moncaster, PloS One, 2010). Aβ interacts with crystallin proteins in the lens to create light scattering aggregates. Crystallins comprise ∼90% of lens protein in mature lens fiber cells and undergo various post-translational modifications during aging that disrupt the normal functioning of the proteins, facilitating aggregation, insolubilization and light scattering. Here, we expand on previous work by us and others and investigated the aging effect of crystallins in an Aβ-independent and Aβ-potentiated environment and the effect on light scattering in lenses from aged (27 months) wild-type and Alzheimer's disease transgenic mice (Tg2576). Mice were bred, maintained and genotyped at Boston University. Mice were sacrificed at 27 months of age, perfused with phosphate buffer saline, lenses were isolated and then imaged under two different sources of light using a D70 digital Nikon camera and a custom-adapted Zeiss stereophotomicroscope. Wild-type aged mice demonstrated increased light scattering in two distinct concentric layers (cortical and outer nuclear) in the lens compared to young mice. Furthermore, Tg2576 aged mice showed increased scattering in the cortical layer compared to wild-type aged mice. Two distinct light scattering layers of the lens are affected during aging involving Aβ-potentiated mechanisms in Tg2576 mice and Aβ-independent mechanisms in wild-type mice.

Two eyes for two purposes: in situ evidence for asymmetric vision in the cockeyed squids Histioteuthis heteropsis and Stigmatoteuthis dofleini.

The light environment of the mesopelagic realm of the ocean changes with both depth and viewer orientation, and this has probably driven the high diversity of visual adaptations found among its inhabitants. The mesopelagic 'cockeyed' squids of family Histioteuthidae have unusual eyes, as the left and right eyes are dimorphic in size, shape and sometimes lens pigmentation. This dimorphism may be an adaptation to the two different sources of light in the mesopelagic realm, with the large eye oriented upward to view objects silhouetted against the dim, downwelling sunlight and the small eye oriented slightly downward to view bioluminescent point sources. We used in situ video footage from remotely operated vehicles in the Monterey Submarine Canyon to observe the orientation behaviour of 152 Histioteuthis heteropsis and nine Stigmatoteuthis dofleini We found evidence for upward orientation in the large eye and slightly downward orientation in the small eye, which was facilitated by a tail-up oblique body orientation. We also found that 65% of adult H. heteropsis (n = 69) had yellow pigmentation in the lens of the larger left eye, which may be used to break the counterillumination camouflage of their prey. Finally, we used visual modelling to show that the visual returns provided by increasing eye size are much higher for an upward-oriented eye than for a downward-oriented eye, which may explain the development of this unique visual strategy.This article is part of the themed issue 'Vision in dim light'.

Effect Of Various Light-Emitting Diodes On Growth And Photosynthetic Pigments Of Banana (Musa Acuminata) Cv. Grande Naine In Vitro Plantlets

In vitro culture of plant species most commonly uses fluorescent lamps as a light source. Other sources of illumination, LEDs (Light-emitting diodes) have proven to be more efficient for in vitro culture. In the conducted experiment, the effect of various LEDs on the in vitro morphogenesis, proliferation of shoots, growth & rooting of Banana (Musa acuminata) cv. Grande Naine was observed. For this purpose, 5 different sources of light were tested under a 16-h photoperiod: fluorescent lamps (Fl), white (W), red (R), blue (B), and B/R (1:1). The proliferation rate was higher with R LEDs compared with Fl light, although shoots have a lower length under R LEDs. Under B/R LEDs, maximum shoot elongation was obtained. LEDs did not enhance the rooting of shoots but increased the photosynthetic pigments content under B/R, which contributed to the acclimation process of in vitro plantlets. Our results revealed that the spectrum of different light sources produced different effects during the in vitro cloning of Grande naine.

The Effect of Light Quality on Growth and Development of In Vitro Plantlet of Stevia rebaudiana Bertoni

Fluorescent lamps are the most commonly used light source for the in vitro culture of various plant species. However, there are other sources of illumination, such as light-emitting diodes (LEDs), which have proven to be more efficient for in vitro culture. In the present study, we evaluated the effect of LEDs on the in vitro morphogenesis, proliferation of shoots, growth and rooting of Stevia rebaudiana Bertoni. For that, five different sources of light were tested under a 16-h photoperiod: fluorescent lamps (Fl), white LEDs (W), red LEDs (R), blue LEDs (B) and a combination of blue and red LEDs (B/R, 1:1). The proliferation rate was higher with R LEDs compared with Fl light, although shoots have a lower length under R LEDs. Under B/R LEDs, maximum shoot elongation was obtained. During rooting, LEDs did not improve the rooting of shoots but increased the content of photosynthetic pigments, which contributed to the acclimation process of in vitro plantlets. Our results revealed that the spectrum of different light sources produced different effects during the in vitro culture of S. rebaudiana.

Influences of different light sources and light/dark cycles on anthocyanin accumulation and plant growth in Petunia

Anthocyanin accumulation and plant growth were examined in petunia (NT and transgenic plants) by determining the effects of different sources of light and varying light/dark cycles. Red light significantly enhanced anthocyanin content of B-peru+mPAP1; however, it had a negative effect on anthocyanin production in RsMYB1 plants. In general, white light was found to be reasonable for anthocyanin accumulation in all plants. In case of light/dark cycles, application of seven days of light:14 days of dark significantly enhanced anthocyanin content. We found that anthocyanin content detected in transgenic plants expressing anthocyanin regulatory transcription factor genes (B-peru+mPAP1 or RsMYB1) was higher than that in NT plants in all treatments. Plant growth was also influenced by the different light sources and dark/light cycles. Taken together, our results suggest that light source and light/dark cycle play an important role in anthocyanin production and plant growth. The choice of the optimal conditions is also important for anthocyanin production and plant growth depending on NT or transgenic plants carrying anthocyanin regulatory transcription factors.