Bioinspired Compound Eyes for Diffused Light-Harvesting Application

2022 ◽  
Author(s):  
Xinxue Wu ◽  
Chaolong Fang ◽  
Wangdong Xu ◽  
Dawei Zhang
Keyword(s):  
Light Harvesting ◽  
Compound Eyes ◽  
Diffused Light

Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

1990 ◽  
Vol 48 (3) ◽  
pp. 430-431
Author(s):  
Maria Anna Pabst
Keyword(s):  
Apis Mellifera ◽  
Distal Part ◽  
Cell Layer ◽  
Single Layer ◽  
Photoreceptor Cells ◽  
Distal Segment ◽  
Compound Eyes ◽  
Thin Sections ◽  
Ultrastructural Studies ◽  
Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

High-Resolution electron crystallography of the light-harvesting chlorophyll-a/b protein complex from chloroplast membranes

1990 ◽  
Vol 48 (1) ◽  
pp. 610-610
Author(s):  
Werner Kühlbrandt ◽  
Da Neng Wang ◽  
K.H. Downing
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Chlorophyll A ◽  
Protein Complex ◽  
Structural Integrity ◽  
Light Harvesting ◽  
Lhc Ii ◽  
Diffraction Patterns ◽  
Difference Fourier ◽  
2D Crystals

The light-harvesting chlorophyll-a/b protein complex (LHC-II) is the most abundant membrane protein in the chloroplasts of green plants where it functions as a molecular antenna of solar energy for photosynthesis. We have grown two-dimensional (2d) crystals of the purified, detergent-solubilized LHC-II . The crystals which measured 5 to 10 μm in diameter were stabilized for electron microscopy by washing with a 0.5% solution of tannin. Electron diffraction patterns of untilted 2d crystals cooled to 130 K showed sharp spots to 3.1 Å resolution. Spot-scan images of 2d crystals were recorded at 160 K with the Berkeley microscope . Images of untilted crystals were processed, using the unbending procedure by Henderson et al . A projection map of the complex at 3.7Å resolution was generated from electron diffraction amplitudes and high-resolution phases obtained by image processing .A difference Fourier analysis with the same image phases and electron diffraction amplitudes recorded of frozen, hydrated specimens showed no significant differences in the 3.7Å projection map. Our tannin treatment therefore does not affect the structural integrity of the complex.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

New species of bristletails of the genus Lepismachilis (Archaeognatha: Machilidae) from Serbia and Montenegro

2018 ◽  
Vol 58 (2) ◽  
pp. 577-587
Author(s):  
Vladimir Kaplin
Keyword(s):  
New Species ◽  
Balkan Peninsula ◽  
Species Group ◽  
Compound Eyes ◽  
Serbia And Montenegro ◽  
Sensory Field ◽  
Fore Femur ◽  
Three New Species

Abstract The fauna of bristletails of the genus Lepismachilis Verhoeff, 1910 in Montenegro and Serbia includes only one species L. (Berlesilis) targionii (Grassi, 1887) with 2 + 2 eversible vesicles on abdominal urocoxites II–VI. Three new species of this genus are described: L. (Lepismachilis) prijepolja sp. nov., L. (Lepismachilis) limensa sp. nov. from Serbia, and L. (Lepismachilis) alexandrae sp. nov. from Montenegro. All described new species belong to the species group of the subgenus Lepismachilis s. str. with 2 + 2 eversible vesicles on abdominal urocoxites II–V. Lepismachilis prijepolja sp. nov. differs from L. y-signata Kratochvíl, 1945 and L. notata Stach, 1919 by the color, drawings and ratios of the compound eyes; ratios of sensory field on fore femur of male, number of divisions of ovipositor. Lepismachilis limensa sp. nov. differs from L. hauseri Bitsch, 1974 and L. abchasica Kaplin, 2017 by ratios of paired ocelli, sensory field on fore femur of male; ratios and chaetotaxy of maxillary and labial palps. Lepismachilis alexandrae sp. nov. differs from L. abchasica by the drawings of the compound eyes; ratios of paired ocelli, sensory field on fore femur of male; number of divisions of the parameres and gonapophyses. A list of the Machilidae occurring in Balkan Peninsula is also provided.

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