Influence of Light of Different Spectral Compositions on the Growth, Photosynthesis, and Expression of Light-Dependent Genes of Scots Pine Seedlings

Varying the spectral composition of light is one of the ways to accelerate the growth of conifers under artificial conditions for the development of technologies and to obtain sustainable seedlings required to preserve the existing areas of forests. We studied the influence of light of different quality on the growth, gas exchange, fluorescence indices of Chl a, and expression of key light-dependent genes of Pinus sylvestris L. seedlings. It was shown that in plants growing under red light (RL), the biomass of needles and root system increased by more than two and three times, respectively, compared with those of the white fluorescent light (WFL) control. At the same time, the rates of photosynthesis and respiration in RL and blue light (BL) plants were lower than those of blue red light (BRL) plants, and the difference between the rates of photosynthesis and respiration, which characterizes the carbon balance, was maximum under RL. RL influenced the number of xylem cells, activated the expression of genes involved in the transduction of cytokinin (Histidine-containing phosphotransfer 1, HPT1, Type-A Response Regulators, RR-A) and auxin (Auxin-induced protein 1, Aux/IAA) signals, and reduced the expression of the gene encoding the transcription factor phytochrome-interacting factor 3 (PIF3). It was suggested that RL-induced activation of key genes of cytokinin and auxin signaling might indicate a phytochrome-dependent change in cytokinins and auxins activity.

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Phytochrome Action in the Induction of Plowering in Short-day Plants: Effect of Photoperiod Quality

Functional Plant Biology ◽

10.1071/pp9740445 ◽

1974 ◽

Vol 1 (3) ◽

pp. 445 ◽

Cited By ~ 7

Author(s):

RW King

Keyword(s):

Photosynthetic Pigments ◽

Prolonged Exposure ◽

Dark Period ◽

Red Light ◽

Spectral Composition ◽

Chenopodium Rubrum ◽

Fluorescent Light ◽

Flowering Response ◽

Short Day ◽

Red Radiation

Seedlings of Phavbitis nil and Chenopodium rubrum flower in response to a single inductive dark period preceded and followed by continuous fluorescent light. However, when a far-red irradiation for 1 h or longer was substituted for fluorescent light, the flowering response to an ensuing dark period could be completely inhibited or enhanced up to threefold depending on when the far-red exposure commenced. Evidence of red/far-red photoreversibility established phytochrome as the photoreceptor controlling these responses. There was no indication of the involvement of photosynthetic pigments. For P. nil prolonged exposure (1.5-6 h) to far-red radiation during the photoperiod could shorten (2-3 h) or lengthen (2 h) the duration of darkness required for flowering. The degree of change depended on whether the far-red radiation was imposed just prior to darkness (shortening) or about 9 h prior to darkness (lengthening). In a similar manner the spectral composition of the photoperiod influenced the timing during darkness for earliest sensitivity to brief (5 min) red light interruptions. The shorter the critical dark period, the earlier in darkness the seedlings became sensitive to red light interruptions of darkness. It is clear that the form of phytochrome during the photoperiod influences the timing of phytochrome- linked processes in darkness. Two explanations discussed are a coupling via rhythmic changes in substrate on which phytochrome acts, and an effect on phytochrome reactions which alters the timing of Pf, disappearance during a subsequent dark period.

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Carbapenem-Resistant Pseudomonas aeruginosa Strains-Distribution of the Essential Enzymatic Virulence Factors Genes

Antibiotics ◽

10.3390/antibiotics10010008 ◽

2020 ◽

Vol 10 (1) ◽

pp. 8

Author(s):

Tomasz Bogiel ◽

Małgorzata Prażyńska ◽

Joanna Kwiecińska-Piróg ◽

Agnieszka Mikucka ◽

Eugenia Gospodarek-Komkowska

Keyword(s):

Pseudomonas Aeruginosa ◽

Alkaline Protease ◽

Virulence Genes ◽

Virulence Gene ◽

Hospital Environment ◽

Gene Encoding ◽

Virulence Gene Expression ◽

Carbapenem Resistant ◽

Antimicrobial Resistance Genes ◽

The Difference

Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with increasing isolation frequency in nosocomial infections. Herein, we investigated whether antimicrobial-resistant P. aeruginosa strains, e.g., metallo-beta-lactamase (MBL)-producing isolates, may possess a reduced number of virulence genes, resulting from appropriate genome management to adapt to a changing hospital environment. Hospital conditions, such as selective pressure, may lead to the replacement of virulence genes by antimicrobial resistance genes that are crucial to survive under current conditions. The study aimed to compare, using PCR, the frequency of the chosen enzymatic virulence factor genes (alkaline protease-aprA, elastase B-lasB, neuraminidases-nan1 and nan2, and both variants of phospholipase C-plcH and plcN) to MBL distribution among 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. The gene encoding alkaline protease was noted with the highest frequency (100%), while the neuraminidase-1 gene was observed in 37.4% of the examined strains. The difference in lasB and nan1 prevalence amongst the MBL-positive and MBL-negative strains, was statistically significant. Although P. aeruginosa virulence is generally more likely determined by the complex regulation of the virulence gene expression, herein, we found differences in the prevalence of various virulence genes in MBL-producers.

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The Preferences of Different Cultivars of Lettuce Seedlings (Lactuca sativa L.) for the Spectral Composition of Light

Agronomy ◽

10.3390/agronomy11061211 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1211

Author(s):

Barbara Frąszczak ◽

Monika Kula-Maximenko

Keyword(s):

Chlorophyll Content ◽

Blue Light ◽

White Light ◽

Leaf Shape ◽

Red Light ◽

Spectral Composition ◽

Fresh Weight ◽

Light Spectrum ◽

Dark Green ◽

Relative Chlorophyll Content

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

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Decoding the molecular mechanism of parthenocarpy in Musa spp. through protein–protein interaction network

Scientific Reports ◽

10.1038/s41598-021-93661-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Suthanthiram Backiyarani ◽

Rajendran Sasikala ◽

Simeon Sharmiladevi ◽

Subbaraya Uma

Keyword(s):

Candidate Genes ◽

Protein Interaction ◽

Target Genes ◽

Interaction Network ◽

Enrichment Analysis ◽

Auxin Signaling ◽

Pathway Enrichment Analysis ◽

Ppi Network ◽

Protein Protein Interaction ◽

The Difference

AbstractBanana, one of the most important staple fruit among global consumers is highly sterile owing to natural parthenocarpy. Identification of genetic factors responsible for parthenocarpy would facilitate the conventional breeders to improve the seeded accessions. We have constructed Protein–protein interaction (PPI) network through mining differentially expressed genes and the genes used for transgenic studies with respect to parthenocarpy. Based on the topological and pathway enrichment analysis of proteins in PPI network, 12 candidate genes were shortlisted. By further validating these candidate genes in seeded and seedless accession of Musa spp. we put forward MaAGL8, MaMADS16, MaGH3.8, MaMADS29, MaRGA1, MaEXPA1, MaGID1C, MaHK2 and MaBAM1 as possible target genes in the study of natural parthenocarpy. In contrary, expression profile of MaACLB-2 and MaZEP is anticipated to highlight the difference in artificially induced and natural parthenocarpy. By exploring the PPI of validated genes from the network, we postulated a putative pathway that bring insights into the significance of cytokinin mediated CLAVATA(CLV)–WUSHEL(WUS) signaling pathway in addition to gibberellin mediated auxin signaling in parthenocarpy. Our analysis is the first attempt to identify candidate genes and to hypothesize a putative mechanism that bridges the gaps in understanding natural parthenocarpy through PPI network.

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Longitudinal changes in the kinetic response to heavy-intensity exercise in children

Journal of Applied Physiology ◽

10.1152/japplphysiol.00784.2003 ◽

2004 ◽

Vol 97 (2) ◽

pp. 460-466 ◽

Cited By ~ 35

Author(s):

Samantha G. Fawkner ◽

Neil Armstrong

Keyword(s):

Slow Component ◽

Phase 1 ◽

Exponential Model ◽

Cycle Ergometer ◽

Primary Component ◽

Total Change ◽

Exercise Tests ◽

Longitudinal Changes ◽

Dependent Change ◽

The Difference

The purpose of this study was to investigate longitudinal changes with age in the kinetic response to cycling at heavy-intensity exercise in boys and girls. Twenty-two prepubertal children (13 male, 9 female) carried out a series of exercise tests on two test occasions with a 2-yr interval. On each test occasion, the subject completed multiple transitions from baseline to 40% of the difference between their previously determined V-slope and peak O2 uptake (V̇o2) for 9 min on an electronically braked cycle ergometer. Each subject's breath-by-breath responses were interpolated to 1-s intervals, time aligned, and averaged. The data after phase 1 were fit with 1) a double exponential model and 2) a single exponential model within a fitting window that was previously identified to exclude the slow component. There were no significant differences in the parameters of the primary component between each model. Subsequent analysis was carried out using model 2. The V̇o2 slow component was computed as the difference between the amplitude of the primary component and the end-exercise V̇o2 and was expressed as the percent contribution to the total change in V̇o2. Over the 2-yr period, the primary time constant (boys 16.8 ± 5.3 and 21.7 ± 5.3 s, girls 21.1 ± 8.1 and 26.4 ± 8.4 s, first and second occasion, respectively) and the relative amplitude of the slow component (boys 9.4 ± 4.6 and 13.8 ± 5.3%, girls 10.3 ± 2.4 and 15.5 ± 2.8%, first and second occasion, respectively) significantly increased with no sex differences. The data demonstrate that children do display a slow-component response to exercise and are consistent with an age-dependent change in the muscles' potential for O2 utilization.

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Effects of specific wavelength spectra on antioxidant stress and cell damage of the ornamental cleaner shrimp Lysmata amboinensis (De Man, 1888) (Decapoda, Caridea, Lysmatidae) exposed to changing saline environments

Crustaceana ◽

10.1163/15685403-00003826 ◽

2018 ◽

Vol 91 (10) ◽

pp. 1231-1245 ◽

Cited By ~ 2

Author(s):

Jong Ryeol Choe ◽

Ji Yong Choi ◽

Jin Ah Song ◽

Cheol Young Choi

Keyword(s):

Cell Damage ◽

Red Light ◽

Aquatic Organisms ◽

Major Influence ◽

Fluorescent Light ◽

Saline Environments ◽

Positive Effects ◽

Negative Results ◽

Antioxidant Stress ◽

Cleaner Shrimp

Abstract A variety of environmental factors have a major influence on the survival of aquatic organisms, particularly light and salinity, changes in which lead to a range of physiological changes. In the present study, we investigated the levels of stress caused by changes in salinity in the ornamental cleaner shrimp, Lysmata amboinensis, as well as the effect of specific light wavelengths following stress to changes in salinity. We measured the activity of superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO) in the tissues (gill, hepatopancreas, and muscle) for three days after irradiating shrimp with specific wavelengths of light [red (630 nm), green (520 nm), and blue (455 nm)] at two intensities (0.5 and 1.0 W/m2) following exposure to different saline environments [25 practical salinity units (psu), 30 psu, 35 psu (normal seawater), and 40 psu]. DNA damage was measured using comet assays. Although all of the experimental groups exhibited negative results to changes in salinity, the green and red light groups exhibited positive effects when compared to the other wavelengths and fluorescent light. The effect of wavelength was not influenced by the intensity. In conclusion, the light of green and red wavelengths effectively reduces antioxidant stress and cell damage in cleaner shrimp.

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Susceptibility of Pseudomonas aeruginosa Dispersed Cells to Antimicrobial Agents Is Dependent on the Dispersion Cue and Class of the Antimicrobial Agent Used

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00846-17 ◽

2017 ◽

Vol 61 (12) ◽

Cited By ~ 22

Author(s):

Jacob R. Chambers ◽

Kathryn E. Cherny ◽

Karin Sauer

Keyword(s):

Antimicrobial Agents ◽

Expression Patterns ◽

Drug Susceptibility ◽

Exponential Phase ◽

Planktonic Cells ◽

Additional Time ◽

Modification System ◽

Expression Of Genes ◽

The Difference ◽

Dispersed Cells

ABSTRACT The biofilm life cycle is characterized by the transition of planktonic cells exhibiting high susceptibly to antimicrobial agents to a biofilm mode of growth characterized by high tolerance to antimicrobials, followed by dispersion of cells from the biofilm back into the environment. Dispersed cells, however, are not identical to planktonic cells but have been characterized as having a unique transitionary phenotype relative to biofilm and planktonic cells, with dispersed cells attaching in a manner similar to exponential-phase cells, but demonstrating gene expression patterns that are distinct from both exponential and stationary-phase planktonic cells. This raised the question whether dispersed cells are as susceptible as planktonic cells and whether the dispersion inducer or the antibiotic class affects the drug susceptibility of dispersed cells. Dispersed cells obtained in response to dispersion cues glutamate and nitric oxide (NO) were thus exposed to tobramycin and colistin. Although NO-induced dispersed cells were as susceptible to colistin and tobramycin as exponential-phase planktonic cells, glutamate-induced dispersed cells were susceptible to tobramycin but resistant to colistin. The difference in colistin susceptibility was independent of cellular c-di-GMP levels, with modulation of c-di-GMP failing to induce dispersion. Instead, drug susceptibility was inversely correlated with LPS modification system and the biofilm-specific transcriptional regulator BrlR. The susceptibility phenotype of glutamate-induced dispersed cells to colistin was found to be reversible, with dispersed cells being rendered as susceptible to colistin within 2 h postdispersion, though additional time was required for dispersed cells to display expression of genes indicative of exponential growth.

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Acclimatization of symbiotic corals to mesophotic light environments through wavelength transformation by fluorescent protein pigments

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.0320 ◽

2017 ◽

Vol 284 (1858) ◽

pp. 20170320 ◽

Cited By ~ 32

Author(s):

Edward G. Smith ◽

Cecilia D'Angelo ◽

Yoni Sharon ◽

Dan Tchernov ◽

Joerg Wiedenmann

Keyword(s):

Fluorescent Protein ◽

Fluorescent Proteins ◽

Environmental Gradients ◽

Red Light ◽

Spectral Composition ◽

Light Environment ◽

Homogeneous Distribution ◽

Red Fluorescent Proteins ◽

Ecological Importance ◽

Colour Morphs

The depth distribution of reef-building corals exposes their photosynthetic symbionts of the genus Symbiodinium to extreme gradients in the intensity and spectral quality of the ambient light environment. Characterizing the mechanisms used by the coral holobiont to respond to the low intensity and reduced spectral composition of the light environment in deeper reefs (greater than 20 m) is fundamental to our understanding of the functioning and structure of reefs across depth gradients. Here, we demonstrate that host pigments, specifically photoconvertible red fluorescent proteins (pcRFPs), can promote coral adaptation/acclimatization to deeper-water light environments by transforming the prevalent blue light into orange-red light, which can penetrate deeper within zooxanthellae-containing tissues; this facilitates a more homogeneous distribution of photons across symbiont communities. The ecological importance of pcRFPs in deeper reefs is supported by the increasing proportion of red fluorescent corals with depth (measured down to 45 m) and increased survival of colour morphs with strong expression of pcRFPs in long-term light manipulation experiments. In addition to screening by host pigments from high light intensities in shallow water, the spectral transformation observed in deeper-water corals highlights the importance of GFP-like protein expression as an ecological mechanism to support the functioning of the coral– Symbiodinium association across steep environmental gradients.

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Light-evoked contraction of red absorbing cones in the Xenopus retina is maximally sensitive to green light

Visual Neuroscience ◽

10.1017/s0952523800002893 ◽

1992 ◽

Vol 8 (3) ◽

pp. 243-249 ◽

Cited By ~ 12

Author(s):

Joseph C. Besharse ◽

Paul Witkovsky

Keyword(s):

Xenopus Laevis ◽

Spectral Sensitivity ◽

Red Light ◽

Green Light ◽

Sensitivity Function ◽

Direct Mechanism ◽

Sensitivity Experiments ◽

Light Stimuli ◽

The Difference ◽

Spectral Sensitivity Function

AbstractTo test the hypothesis that light-evoked cone contraction in eye cups from Xenopus laevis is controlled through a direct mechanism initiated by the cone's own photopigment, we conducted spectral-sensitivity experiments. We estimate that initiation of contraction of red absorbing cones (611 nm) is 1.5 log units more sensitive to green (533 nm) than red (650 nm) light stimuli. The difference is comparable to that predicted from the spectral-sensitivity function of the green absorbing, principal rod (523 nm). Furthermore, 480-nm and 580-nm stimuli which are absorbed nearly equally by the principal rod have indistinguishable effects on cone contraction. We also found that light blockade of nighttime cone elongation is much more sensitive to green than to red light stimuli. Our observations are inconsistent with the hypothesis tested, and suggest that light-regulated cone motility is controlled through an indirect mechanism initiated primarily by the green absorbing, principal rod.

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Relation between Changes in Photosynthetic Rate and Changes in Canopy Level Chlorophyll Fluorescence Generated by Light Excitation of Different Led Colours in Various Background Light

Remote Sensing ◽

10.3390/rs11040434 ◽

2019 ◽

Vol 11 (4) ◽

pp. 434 ◽

Cited By ~ 1

Author(s):

Linnéa Ahlman ◽

Daniel Bånkestad ◽

Torsten Wik

Keyword(s):

Steady State ◽

Light Quality ◽

Incident Light ◽

Red Light ◽

Intensity Level ◽

Potential Candidate ◽

Light Emitting ◽

Background Light ◽

Light Regimes ◽

The Difference

Using light emitting diodes (LEDs) for greenhouse illumination enables the use of automatic control, since both light quality and quantity can be tuned. Potential candidate signals when using biological feedback for light optimisation are steady-state chlorophyll a fluorescence gains at 740 nm, defined as the difference in steady-state fluorescence at 740 nm divided by the difference in incident light quanta caused by (a small) excitation of different LED colours. In this study, experiments were conducted under various background light (quality and quantity) to evaluate if these fluorescence gains change relative to each other. The light regimes investigated were intensities in the range 160–1000 μ mol m − 2 s − 1 , and a spectral distribution ranging from 50% to 100% red light. No significant changes in the mutual relation of the fluorescence gains for the investigated LED colours (400, 420, 450, 530, 630 and 660 nm), could be observed when the background light quality was changed. However, changes were noticed as function of light quantity. When passing the photosynthesis saturate intensity level, no further changes in the mutual fluorescence gains could be observed.

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