scholarly journals 2P101 Structure and function of feast/famine regulatory proteins : 3.interaction between the FL11 protein and the fl11 promoter

2004 ◽  
Vol 44 (supplement) ◽  
pp. S135
Author(s):  
K. Yokoyama ◽  
H. Koike ◽  
S.A. Ishijima ◽  
L. Clowney ◽  
T. Kikuchi ◽  
...  
Keyword(s):  
Structure And Function ◽  
Regulatory Proteins ◽  
And Function

Structure and function of complement C5 convertase enzymes

2002 ◽  
Vol 30 (6) ◽  
pp. 1006-1010 ◽  
Author(s):  
M. K. Pangburn ◽  
N. Rawal
Keyword(s):  
Cell Surface ◽  
Alternative Pathway ◽  
Membrane Attack Complex ◽  
Structure And Function ◽  
Regulatory Proteins ◽  
Covalent Attachment ◽  
Cleavage Rate ◽  
And Function ◽  
Natural Decay ◽  
The Complement System

The multisubunit enzymes of the complement system that cleave C5 have many unusual properties, the most striking of which is that they acquire their specificity for C5 following cleavage of another substrate C3. C5 convertases are assemblies of two proteins C4b and C2a (classical or lectin pathways) or C3b and Bb (alternative pathway) and additional C3b molecules. The catalytic complexes (C4b, C2a or C3b, Bb) are intrinsically unstable (t1,2 = 1–3 min) and the enzymes are controlled by numerous regulatory proteins that accelerate this natural decay rate. Immediately after assembly, the bi-molecular enzymes preferentially cleave the protein C3 and exhibit poor activity toward C5 (a Km of approx. 25 μM and a C5 cleavage rate of 0.3-1 C5/min at Vmax). Efficient C3 activation results in the covalent attachment of C3b to the cell surface and to the enzyme itself, resulting in formation of C3b-C3b and C4b-C3b complexes. Our studies have shown that deposition of C3b alters the specificity of the enzymes of both pathways by changing the Km for C5 more than 1000-fold from far above the physiological C5 concentration to far below it. Thus, after processing sufficient C3 at the surface of a microorganism, the enzymes switch to processing C5, which initiates the formation of the cytolytic membrane attack complex of complement.

scholarly journals Plasma membrane tension regulates eisosome structure and function

2020 ◽  
Vol 31 (4) ◽  
pp. 287-303 ◽  
Author(s):  
Daniel Appadurai ◽  
Lincoln Gay ◽  
Akshay Moharir ◽  
Michael J. Lang ◽  
Mara C. Duncan ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Environmental Changes ◽  
Structure And Function ◽  
Regulatory Proteins ◽  
Nutrient Transporters ◽  
Membrane Tension ◽  
Membrane Stress ◽  
Yeast Plasma Membrane ◽  
And Function

Eisosomes are furrows of the yeast plasma membrane that are involved in the regulation of nutrient transporters and membrane stress pathways. Environmental changes affect plasma membrane tension and fluidity, which change both the eisosome structure and the localization of nutrient transporters and regulatory proteins to the eisosome.

scholarly journals 2P100 Structure and function of feast/famine regulatory proteins : 2. Interacton of DM1 with ligands studied using a crystal structure

2004 ◽  
Vol 44 (supplement) ◽  
pp. S134
Author(s):  
H. Koike ◽  
S. A. Ishijima ◽  
M. Sakuma ◽  
K. Minahiro ◽  
M. Suzuki
Keyword(s):  
Crystal Structure ◽  
Structure And Function ◽  
Regulatory Proteins ◽  
And Function

scholarly journals Regulatory proteins in placental angiogenesis

Biomedicine ◽  
2021 ◽  
Vol 41 (4) ◽  
pp. 694-700
Author(s):  
Anil Kumar K. V. ◽  
Kavitha S. ◽  
Sreekanth K. S.
Keyword(s):  
Growth Factors ◽  
Structure And Function ◽  
Angiogenic Factors ◽  
Regulatory Proteins ◽  
Vascular Growth ◽  
Placental Angiogenesis ◽  
Physiological Phenomenon ◽  
Vessel Growth ◽  
Vasculogenesis And Angiogenesis ◽  
And Function

The vasculature of the placenta plays a crucial role during the course of pregnancy in order to maintain the growing need of the fetus. Abnormal placental structure and function significantly increase the risk of stillbirth. Various growth factors and cytokines play an important role in the vasculogenesis and angiogenesis of placenta. These processes are stimulated by various pro-angiogenic factors. The activities of these factors are also stimulated by hypoxia. In some of the physiological phenomenon like ovulation, embryogenesis as well as in wound healing intense blood vessel growth can be seen similar to that seen in placenta. Therefore, factors that induce and maintain placental vascular growth and function are of considerable developmental and clinical significance. The total arterial architecture may also depend upon the pro-angiogenic factors. Hormones and other growth factors are other contributors of this vasculogenesis and angiogenesis. Any dysfunction of factors can lead to foetal hypoxia and related complications. This review describes the major growth factors and their significant role in vasculogenesis and angiogenesis of placenta.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

Osseointegration interface of calcified bone and endosseous implants

1992 ◽  
Vol 50 (2) ◽  
pp. 1096-1097
Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley
Keyword(s):  
Structure And Function ◽  
Titanium Implants ◽  
En Bloc ◽  
Endosseous Implants ◽  
Ultrastructural Studies ◽  
The Past ◽  
Cacodylate Buffer ◽  
One Year ◽  
And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

Use of human autoantibodies and immunoelectron microscopy to study structure and function of the nucleolus and nuclear bodies

1992 ◽  
Vol 50 (1) ◽  
pp. 506-507
Author(s):  
Robert L. Ochs
Keyword(s):  
Electron Microscopy ◽  
Structure And Function ◽  
Nuclear Bodies ◽  
Nuclear Interior ◽  
Coiled Bodies ◽  
Interchromatin Granules ◽  
And Function ◽  
Conventional Electron Microscopy ◽  
Perichromatin Granules ◽  
Perichromatin Fibrils

By conventional electron microscopy, the formed elements of the nuclear interior include the nucleolus, chromatin, interchromatin granules, perichromatin granules, perichromatin fibrils, and various types of nuclear bodies (Figs. 1a-c). Of these structures, all have been reasonably well characterized structurally and functionally except for nuclear bodies. The most common types of nuclear bodies are simple nuclear bodies and coiled bodies (Figs. 1a,c). Since nuclear bodies are small in size (0.2-1.0 μm in diameter) and infrequent in number, they are often overlooked or simply not observed in any random thin section. The rat liver hepatocyte in Fig. 1b is a case in point. Historically, nuclear bodies are more prominent in hyperactive cells, they often occur in proximity to nucleoli (Fig. 1c), and sometimes they are observed to “bud off” from the nucleolar surface.

Depletion and Reconstitution of Active E. Coli Ribosomes

1975 ◽  
Vol 33 ◽  
pp. 640-641
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Protein Biosynthesis ◽  
Large Subunit ◽  
High Resolution Electron Microscopy ◽  
Small Subunit ◽  
Structure And Function ◽  
Biologically Active ◽  
Biological Macromolecules ◽  
E Coli ◽  
Resolution Electron ◽  
And Function

Correlations between structure and function of biological macromolecules have been studied intensively for many years, mostly by indirect methods. High resolution electron microscopy is a unique tool which can provide such information directly by comparing the conformation of biopolymers in their biologically active and inactive state. We have correlated the structure and function of ribosomes, ribonucleoprotein particles which are the site of protein biosynthesis. 70S E. coli ribosomes, used in this experiment, are composed of two subunits - large (50S) and small (30S). The large subunit consists of 34 proteins and two different ribonucleic acid molecules. The small subunit contains 21 proteins and one RNA molecule. All proteins (with the exception of L7 and L12) are present in one copy per ribosome.This study deals with the changes in the fine structure of E. coli ribosomes depleted of proteins L7 and L12. These proteins are unique in many aspects.

The Laryngeal Epithelium in Reflux

2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar
Keyword(s):  
Laryngopharyngeal Reflux ◽  
Critical Role ◽  
Structure And Function ◽  
Laryngeal Disease ◽  
Health And Disease ◽  
And Function ◽  
The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

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