scholarly journals The Three-Dimensional Structure of Giardia lamblia Virus and its Comparison to Other Members of the Family Totiviridae

2013 ◽  
Vol 19 (S2) ◽  
pp. 88-89
Author(s):  
M.E. Janssen ◽  
K.N. Parent ◽  
Y. Takagi ◽  
M.L. Nibert ◽  
T.S. Baker

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Bin Li ◽  
Bin Lu ◽  
Xuewen Guo ◽  
Shenghui Hu ◽  
Guihu Zhao ◽  
...  

Purpose. To screen out pathogenic genes in a Chinese family with congenital cataract and iris coloboma. Material and Methods. A three-generation family with congenital cataract and iris coloboma from a Han ethnicity was recruited. DNA was extracted from peripheral blood samples collected from all individuals in the family. Whole exon sequencing was employed for screening the disease-causing gene mutations in the proband, and Sanger sequencing was used for other members of the family and a control group of 500 healthy individuals. Bioinformatics analysis and three-dimensional structure predictions were used to predict the impact of amino acid changes on protein structure and function. Results. The candidate genes of cataract and iris coloboma were successfully screened out. A heterozygote mutation, CRYGD c.70C>A (p.P24T), was identified as cosegregating with congenital cataracts, while another heterozygous mutation, WFS1 c.1514G>C (p.C505S), which had not been reported previously, cosegregated with congenital iris coloboma. Bioinformatic analyses and three-dimensional structure prediction proved that the three-dimensional structures of WFS1 p.C505S and CRYGD p.P24T changed markedly and may contribute significantly to iris coloboma and congenital cataract, respectively. Conclusions. We report a novel mutation, WFS1 p.C505S, and a known mutation, CRYGD p.P24T, that cosegregate with iris coloboma and congenital cataract, respectively, in a Chinese family. This is the first time the association of WFS1 p.C505S with iris coloboma has been demonstrated, although CRYGD p.P24T has been widely reported as being associated with congenital cataract, especially in the Eastern Asian population. These findings may have future therapeutic benefit for the diagnosis of iris coloboma and congenital cataract. The results may also be relevant in further studies aiming to investigate the molecular pathogenesis of iris coloboma and congenital cataract.


1979 ◽  
Vol 34 (3-4) ◽  
pp. 284-287 ◽  
Author(s):  
Willi A. Ribi

Abstract The three-dimensional structure of the tracheal tapetum lucidum, its reflection properties and the resulting eye glow hue were studied in members of the diurnal butterfly families Pieridae, Nymphalidae, Satyridae and Lycaenidae. Two main groups of tapeta can be distinguished by structural and physiological differences. Whereas in pierids the main tracheal trunk at the bottom of the rhabdom bifurcates into two side branches before bifurcating again more distally, the tracheal trunk in the members of the family Nymphalidae, Satyridae and Lycaenidae investigated first divides into four side brandies. A second bifurcation shortly after the first results in eight subbranches which are regularly arranged between adjoining receptor cells. The broad banded reflection colour from incidently illuminated tapetal structures (at the level of the first bifurcation) varies between and within families but does not change significantly within the same eye. Whereas in nymphalids, satyrids and lycaenids the eye glow hue corresponds with the colour of the tapetal reflection, in pierids it is dominated by the coloured receptor screening pigment.


Author(s):  
Alicia Lammerts van Bueren ◽  
Suzie Otani ◽  
Esben P. Friis ◽  
Keith S. Wilson ◽  
Gideon J. Davies

Thermostable enzymes employ various structural features dictated at the amino-acid sequence level that allow them to maintain their integrity at higher temperatures. Many hypotheses as to the nature of thermal stability have been proposed, including optimized core hydrophobicity and an increase in charged surface residues to enhance polar solvent interactions for solubility. Here, the three-dimensional structure of the family GH11 xylanase from the moderate thermophileThermobifida fuscain its trapped covalent glycosyl-enzyme intermediate complex is presented. Interactions with the bound ligand show fewer direct hydrogen bonds from ligand to protein than observed in previous complexes from other species and imply that binding of the xylan substrate involves several water-mediated hydrogen bonds.


Author(s):  
N. H. Olson ◽  
T. S. Baker ◽  
Wu Bo Mu ◽  
J. E. Johnson ◽  
D. A. Hendry

Nudaurelia capensis β virus (NβV) is an RNA virus of the South African Pine Emperor moth, Nudaurelia cytherea capensis (Lepidoptera: Saturniidae). The NβV capsid is a T = 4 icosahedron that contains 60T = 240 subunits of the coat protein (Mr = 61,000). A three-dimensional reconstruction of the NβV capsid was previously computed from visions embedded in negative stain suspended over holes in a carbon film. We have re-examined the three-dimensional structure of NβV, using cryo-microscopy to examine the native, unstained structure of the virion and to provide a initial phasing model for high-resolution x-ray crystallographic studiesNβV was purified and prepared for cryo-microscopy as described. Micrographs were recorded ∼1 - 2 μm underfocus at a magnification of 49,000X with a total electron dose of about 1800 e-/nm2.


Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.


Author(s):  
José L. Carrascosa ◽  
José M. Valpuesta ◽  
Hisao Fujisawa

The head to tail connector of bacteriophages plays a fundamental role in the assembly of viral heads and DNA packaging. In spite of the absence of sequence homology, the structure of connectors from different viruses (T4, Ø29, T3, P22, etc) share common morphological features, that are most clearly revealed in their three-dimensional structure. We have studied the three-dimensional reconstruction of the connector protein from phage T3 (gp 8) from tilted view of two dimensional crystals obtained from this protein after cloning and purification.DNA sequences including gene 8 from phage T3 were cloned, into Bam Hl-Eco Rl sites down stream of lambda promotor PL, in the expression vector pNT45 under the control of cI857. E R204 (pNT89) cells were incubated at 42°C for 2h, harvested and resuspended in 20 mM Tris HC1 (pH 7.4), 7mM 2 mercaptoethanol, ImM EDTA. The cells were lysed by freezing and thawing in the presence of lysozyme (lmg/ml) and ligthly sonicated. The low speed supernatant was precipitated by ammonium sulfate (60% saturated) and dissolved in the original buffer to be subjected to gel nitration through Sepharose 6B, followed by phosphocellulose colum (Pll) and DEAE cellulose colum (DE52). Purified gp8 appeared at 0.3M NaCl and formed crystals when its concentration increased above 1.5 mg/ml.


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