The Influence of Light Exposure on the Photosynthetic Carbon Utilization of Undaria pinnatifida (Phaeophyceae)

RuBisCO (D-ribulose-l,5-biphosphate carboxylase/oxygenase) is the most aboundant enzyme in the plant cell and it catalyses the key carboxylation reaction of photosynthetic carbon fixation, but also the competing oxygenase reaction of photorespiation. In vitro crystallized RuBisCO has been studied earlier but this investigation concerns in vivo existance of RuBisCO crystals in anthers and leaves ofsugarbeets. For the identification of in vivo protein crystals it is important to be able to determinethe unit cell of cytochemically identified crystals in the same image. In order to obtain the best combination of optimal contrast and resolution we have studied different staining and electron accelerating voltages. It is known that embedding and sectioning can cause deformation and obscure the unit cell parameters.

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Photosynthetic responses of Coffea arabica leaves to a short-term high light exposure in relation to N availability

Physiologia Plantarum ◽

10.1034/j.1399-3054.1997.1010130.x ◽

1997 ◽

Vol 101 (1) ◽

pp. 229-239 ◽

Cited By ~ 1

Author(s):

Jose C. Ramalho ◽

Thos L. Pons ◽

Henri W. Groeneveld ◽

M. Antonieta Nunes

Keyword(s):

Coffea Arabica ◽

Light Exposure ◽

High Light ◽

N Availability ◽

Short Term ◽

Photosynthetic Responses

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A New Model for Quantitative In Vivo Microscopic Analysis of Thrombus Formation and Vascular Recanalisation: The Ear of the Hairless (hr/hr) Mouse

Thrombosis and Haemostasis ◽

10.1055/s-0038-1665420 ◽

1997 ◽

Vol 78 (05) ◽

pp. 1408-1414 ◽

Cited By ~ 25

Author(s):

Frank Roesken ◽

Martin Ruecker ◽

Brigitte Vollmar ◽

Nicole Boeckel ◽

Eberhard Morgenstern ◽

...

Keyword(s):

Endothelial Cell ◽

Light Exposure ◽

Thrombus Formation ◽

Microscopic Analysis ◽

Cell Interaction ◽

Vascular Perfusion ◽

Vessel Occlusion ◽

Endothelial Cell Interaction ◽

Platelet Deposition

SummaryThe alteration of rheological blood properties as well as deterioration of vascular perfusion conditions and cell-cell interactions are major determinants of thrombus formation. Herein, we present an experimental model which allows for quantitative in vivo microscopic analysis of these determinants during both thrombus formation and vascular recanalisation. The model does not require surgical preparation procedures, and enables for repeated analysis of identical microvessels over time periods of days or months, respectively. After i.v. administration of FITC-dextran thrombus formation was induced photochemically by light exposure to individual arterioles and venules of the ear of ten anaesthetised hairless mice. In venules, epiillumination induced rapid thrombus formation with first platelet deposition after 0.59 ± 0.04 min and complete vessel occlusion within 7.48 ±1.31 min. After a 24-h time period, 75% of the thrombosed venules were found recanalised. Marked leukocyte-endothelial cell interaction in those venules indicated persistent endothelial cell activation and/or injury, even after an observation period of 7 days. In arterioles, epi-illumination provoked vasomotion, while thrombus formation was significantly (p <0.05) delayed with first platelet deposition after 2.32 ± 0.22 min and complete vessel occlusion within 20.07 ±3.84 min. Strikingly, only one of the investigated arterioles was found recanalised after 24 h, which, however, did not show leukocyte-endothelial cell interaction. Heparin (300 U/kg, i.v.) effectively counteracted the process of thrombus formation in this model, including both first platelet deposition and vessel occlusion. We conclude that the model of the ear of the hairless mouse allows for distinct in vivo analysis of arteriolar and venular thrombus formation/ recanalisation, and, thus, represents an interesting tool for the study of novel antithrombotic and thrombolytic strategies, respectively.

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Nighttime Blue Light Exposure and Breast Cancer

Osteopathic Family Physician ◽

10.33181/13013 ◽

2021 ◽

pp. 30-33

Author(s):

David Jaynes ◽

Paul Switzer

Keyword(s):

Breast Cancer ◽

Risk Factor ◽

Blue Light ◽

Shift Work ◽

Light Exposure ◽

Night Shift ◽

Background Information ◽

Common Disease ◽

Essential Information ◽

Night Shift Work

The purpose of this article is to provide background information and the current understanding of a less familiar cause of female breast cancer; exposure to ultraviolet light at night. Breast cancer is a common disease that causes significant morbidity and mortality in women. There are several risk factors for breast cancer, most of which are genetic and environmental in nature. An often-overlooked risk factor is exposure to blue light during night shift work, which decreases melatonin production. One of the many cancer-preventing properties of melatonin is to limit estrogen production. Increased lifetime exposure to estrogen is a well-known cause of breast cancer. Awareness of nighttime blue light exposure as a breast cancer risk factor by women doing night shift work and those exposed to nighttime light via smartphones and laptops, is essential information to know so that protective measures can be taken.

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Predicting cold-water bleaching in corals: role of temperature, and potential integration of light exposure

Marine Ecology Progress Series ◽

10.3354/meps13336 ◽

2020 ◽

Vol 642 ◽

pp. 133-146

Author(s):

PC González-Espinosa ◽

SD Donner

Keyword(s):

Coral Bleaching ◽

Cold Water ◽

Light Exposure ◽

Light Attenuation ◽

Florida Keys ◽

Cold Temperature ◽

Warm Water ◽

Coral Tissue ◽

Effect Of Temperature ◽

Type I

Warm-water growth and survival of corals are constrained by a set of environmental conditions such as temperature, light, nutrient levels and salinity. Water temperatures of 1 to 2°C above the usual summer maximum can trigger a phenomenon known as coral bleaching, whereby disruption of the symbiosis between coral and dinoflagellate micro-algae, living within the coral tissue, reveals the white skeleton of coral. Anomalously cold water can also lead to coral bleaching but has been the subject of limited research. Although cold-water bleaching events are less common, they can produce similar impacts on coral reefs as warm-water events. In this study, we explored the effect of temperature and light on the likelihood of cold-water coral bleaching from 1998-2017 using available bleaching observations from the Eastern Tropical Pacific and the Florida Keys. Using satellite-derived sea surface temperature, photosynthetically available radiation and light attenuation data, cold temperature and light exposure metrics were developed and then tested against the bleaching observations using logistic regression. The results show that cold-water bleaching can be best predicted with an accumulated cold-temperature metric, i.e. ‘degree cooling weeks’, analogous to the heat stress metric ‘degree heating weeks’, with high accuracy (90%) and fewer Type I and Type II errors in comparison with other models. Although light, when also considered, improved prediction accuracy, we found that the most reliable framework for cold-water bleaching prediction may be based solely on cold-temperature exposure.

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The invasive kelp Undaria pinnatifida hosts an epifaunal assemblage similar to native seaweeds with comparable morphologies

Marine Ecology Progress Series ◽

10.3354/meps12321 ◽

2017 ◽

Vol 582 ◽

pp. 45-55 ◽

Cited By ~ 9

Author(s):

R Suárez-Jiménez ◽

CD Hepburn ◽

GA Hyndes ◽

RJ McLeod ◽

RB Taylor ◽

...

Keyword(s):

Undaria Pinnatifida ◽

Epifaunal Assemblage

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Cycled Light Exposure Reduces Fussing and Crying in Very Preterm Infants

PEDIATRICS ◽

10.1542/peds.2011-2671d ◽

2012 ◽

Vol 130 (1) ◽

pp. X33-X33

Keyword(s):

Preterm Infants ◽

Light Exposure ◽

Very Preterm Infants ◽

Very Preterm

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Degradation in a Methyl-phenyl Co-Polymeric Polysilane for LED Applications

MRS Proceedings ◽

10.1557/proc-769-h4.3 ◽

2003 ◽

Vol 769 ◽

Cited By ~ 2

Author(s):

Asha Sharma ◽

Deepak ◽

Monica Katiyar ◽

Satyendra Kumar ◽

V. Chandrasekhar ◽

...

Keyword(s):

Thin Films ◽

Molecular Weight ◽

Light Source ◽

Room Temperature ◽

Light Exposure ◽

Room Temperature Photoluminescence ◽

Pl Spectrum ◽

Pl Intensity ◽

Methyl Phenyl

AbstractThe optical degradation of polysilane copolymer has been studied in spin cast thin films and solutions using light source of 325 nm wavelength. The room temperature photoluminescence (PL) spectrum of these films show a sharp emission at 368 nm when excited with a source of 325 nm. However, the PL intensity deteriorates with time upon light exposure. Further the causes of this degradation have been examined by characterizing the material for its transmission behaviour and changes occurring in molecular weight as analysed by GPC data.

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