scholarly journals FINE STRUCTURAL CHANGES IN PROPLASTIDS DURING PHOTODESTRUCTION OF PIGMENTS

1964 ◽  
Vol 22 (2) ◽  
pp. 443-451 ◽  
Author(s):  
Shimon Klein ◽  
Lawrence Bogorad
Keyword(s):  
Fine Structure ◽  
Levulinic Acid ◽  
Structural Changes ◽  
Prolamellar Body ◽  
Membrane Structures ◽  
Lamellar Structures ◽  
Amino Levulinic Acid ◽  
Stroma Lamellae ◽  
Green Pigments ◽  
Bean Leaves

Etiolated bean leaves supplied δ-amino-levulinic acid in the dark synthesize large amounts of protochlorophyllide which is not converted to chlorophyllide upon illumination of the leaves. The fine structure of the proplastids is not affected by the treatment. When leaves containing "inactive" protochlorophyllide are exposed to light of 700 ft-c for 3 hours, they lose practically all their green pigments. During this period large stacks of closed membrane structures are built up in the region of the prolamellar body. These lamellar structures remain even when no or only traces of pigment are left in the leaves. In untreated control leaves the pigment content remained constant during similar illumination and the structural changes in the plastids consisted of a rearrangement of the vesicles from the prolamellar bodies into strands dispersed through the stroma; lamellae and grana formation occurred later.

scholarly journals EARLY STAGES IN THE DEVELOPMENT OF PLASTID FINE STRUCTURE IN RED AND FAR-RED LIGHT

1964 ◽  
Vol 22 (2) ◽  
pp. 433-442 ◽  
Author(s):  
Shimon Klein ◽  
G. Bryan ◽  
Lawrence Bogorad
Keyword(s):  
Fine Structure ◽  
Stages Of Change ◽  
Structural Changes ◽  
Red Light ◽  
Prolamellar Body ◽  
Lag Phase ◽  
Prolamellar Bodies ◽  
Chlorophyll Accumulation ◽  
Time Required ◽  
Bean Leaves

Developmental changes in fine structure were studied in plastids of etiolated bean leaves during the time required for the protochlorophyllide-chlorophyllide transformation and the following lag phase prior to chlorophyll accumulation. In agreement with some other workers, two distinct stages of change in the fine structure of proplastids were found to occur upon illumination during this period. The first involves a dissociation of the previously fused units in the prolamellar bodies of the proplastids and occurs simultaneously with the protochlorophyllide-chlorophyllide conversion in light of 655 mµ, but not of 682, 700, or 730 mµ. The effect of the red light could not be reversed by a simultaneously supplied stronger far-red irradiation. The energy requirements for these structural changes parallel those for the pigment conversion. During the following step the vesicles which arose from the fused units of the prolamellar body were dispersed in rows through the stroma, and the prolamellar bodies themselves disappeared. For these changes to occur, higher light energies were required and the leaves had to be illuminated for longer periods. A red preillumination seemed to accelerate the development somewhat. The structural changes could be induced by light of 655 mµ, but also, to a lesser degree, of 730 mµ. No measurable additional chlorophyll accumulated during this period. Thus, the structural changes observed were independent of major changes in pigment content.

Photodynamic Therapy of Normal and Balloon-Injured Rat Carotid Arteries Using 5-Amino-Levulinic Acid

Circulation ◽  
1995 ◽  
Vol 91 (2) ◽  
pp. 417-425 ◽  
Author(s):  
Isaac Nyamekye ◽  
Sandra Anglin ◽  
Jean McEwan ◽  
Alexander MacRobert ◽  
Stephen Bown ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Levulinic Acid ◽  
Carotid Arteries ◽  
Amino Levulinic Acid

scholarly journals 5-amino levulinic acid inhibits SARS-CoV-2 infection in vitro

2021 ◽  
Vol 545 ◽  
pp. 203-207
Author(s):  
Yasuteru Sakurai ◽  
Mya Myat Ngwe Tun ◽  
Yohei Kurosaki ◽  
Takaya Sakura ◽  
Daniel Ken Inaoka ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Amino Levulinic Acid

scholarly journals Broad Ultrastructural and Transcriptomic Changes Underlie the Multinucleated Giant Hemocyte Mediated Innate Immune Response against Parasitoids

2021 ◽  
pp. 1-20
Author(s):  
Gyöngyi Cinege ◽  
Lilla B. Magyar ◽  
Attila L. Kovács ◽  
Zita Lerner ◽  
Gábor Juhász ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Structural Changes ◽  
Molecular Mechanisms ◽  
Mechanistic Model ◽  
Parasitoid Wasp ◽  
Innate Immune ◽  
Drosophila Ananassae ◽  
Membrane Structures ◽  
Intracytoplasmic Membrane

Multinucleated giant hemocytes (MGHs) represent a novel type of blood cell in insects that participate in a highly efficient immune response against parasitoid wasps involving isolation and killing of the parasite. Previously, we showed that circulating MGHs have high motility and the interaction with the parasitoid rapidly triggers encapsulation. However, structural and molecular mechanisms behind these processes remained elusive. Here, we used detailed ultrastructural analysis and live cell imaging of MGHs to study encapsulation in <i>Drosophila ananassae</i> after parasitoid wasp infection. We found dynamic structural changes, mainly driven by the formation of diverse vesicular systems and newly developed complex intracytoplasmic membrane structures, and abundant generation of giant cell exosomes in MGHs. In addition, we used RNA sequencing to study the transcriptomic profile of MGHs and activated plasmatocytes 72 h after infection, as well as the uninduced blood cells. This revealed that differentiation of MGHs was accompanied by broad changes in gene expression. Consistent with the observed structural changes, transcripts related to vesicular function, cytoskeletal organization, and adhesion were enriched in MGHs. In addition, several orphan genes encoding for hemolysin-like proteins, pore-forming toxins of prokaryotic origin, were expressed at high level, which may be important for parasitoid elimination. Our results reveal coordinated molecular and structural changes in the course of MGH differentiation and parasitoid encapsulation, providing a mechanistic model for a powerful innate immune response.

Conversaziones 1974

1975 ◽  
Vol 29 (2) ◽  
pp. 163-171
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Cell Walls ◽  
Structural Changes ◽  
Vascular Tissue ◽  
Root Systems ◽  
Plant Roots ◽  
Tracer Studies ◽  
Water Move ◽  
Intact Root

CONVERSAZIONES were held this year on 9 May and 27 June. At the first conversazione twenty-seven exhibits and two films were shown. The fine structure of plant roots in relation to transport of nutrient ions and water was demonstrated by Dr D. T. Clarkson of the A.R.C. Letcombe Laboratory, Wantage and Dr A. W. Robards of the Department of Biology, University of York. Two major pathways by which nutrients and water move radially across the cortex towards the central vascular tissue have been distinguished by the use of tracer studies of adsorption by different zones of intact root systems, microautoradiography and electron microscopy. Movement can be apoplastic through cell walls, or symplastic between cells joined by plasmodesmata. As the root ages, structural changes in the endodermis reduce movement in the former pathway but the symplast is not interrupted by the elaboration of endodermal walls because plasmodesmatal connexions remain intact. These observations help explain the contrasting extent to which different ions and water reach the shoot from young and mature parts of root systems.

Protoheme formation in barley in response to light, dark and delta‐amino levulinic acid

1984 ◽  
Vol 7 (1-5) ◽  
pp. 807-818
Author(s):  
Ibraheem M. Ameen ◽  
Gene W. Miller
Keyword(s):  
Levulinic Acid ◽  
Amino Levulinic Acid
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