scholarly journals Three-Dimensional Structures of the A, B, and CCapsids of Rhesus Monkey Rhadinovirus: Insights into GammaherpesvirusCapsid Assembly, Maturation, and DNAPackaging

2003 ◽  
Vol 77 (24) ◽  
pp. 13182-13193 ◽  
Author(s):  
Xue-Kui Yu ◽  
Christine M. O'Connor ◽  
Ivo Atanasov ◽  
Blossom Damania ◽  
Dean H. Kedes ◽  
...  
Keyword(s):  
Rhesus Monkey ◽  
Three Dimensional ◽  
Model System ◽  
Electron Cryomicroscopy ◽  
Interacting Protein ◽  
Structural Differences ◽  
Dimensional Reconstruction ◽  
Capsid Maturation ◽  
First Time

ABSTRACT Rhesus monkey rhadinovirus (RRV) exhibits high levels of sequence homology to human gammaherpesviruses, such as Kaposi's sarcoma-associated herpesvirus, and grows to high titers in cell cultures, making it a good model system for studying gammaherpesvirus capsid structure and assembly. We have purified RRV A, B, and C capsids, thus for the first time allowing direct structure comparisons by electron cryomicroscopy and three-dimensional reconstruction. The results show that the shells of these capsids are identical and are each composed of 12 pentons, 150 hexons, and 320 triplexes. Structural differences were apparent inside the shells and through the penton channels. The A capsid is empty, and its penton channels are open. The B capsid contains a scaffolding core, and its penton channels are closed. The C capsid contains a DNA genome, which is closely packaged into regularly spaced density shells (25Å apart), and its penton channels are open. The different statuses of the penton channels suggest a functional role of the channels during capsid maturation, and the overall structural similarities of RRV capsids to alphaherpesvirus capsids suggest a common assembly and maturation pathway. The RRV A capsid reconstruction at a 15-Å resolution, the best achieved for gammaherpesvirus particles, reveals overall structural similarities to alpha- and betaherpesvirus capsids. However, the outer regions of the capsid, including densities attributed to the Ta triplex and the small capsomer-interacting protein (SCIP or ORF65), exhibit prominent differences from their structural counterparts in alphaherpesviruses. This structural disparity suggests that SCIP and the triplex, together with tegument and envelope proteins, confer structural and potentially functional specificities to alpha-, beta-, and gammaherpesviruses.

scholarly journals Inside the volcano: Three-dimensional magmatic architecture of a buried shield volcano

Geology ◽  
2020 ◽  
Author(s):  
Faye Walker ◽  
Nick Schofield ◽  
John Millett ◽  
Dave Jolley ◽  
Simon Holford ◽  
...  
Keyword(s):  
Gravity Data ◽  
Three Dimensional ◽  
Shield Volcano ◽  
Plumbing System ◽  
Magma Chambers ◽  
Volcanic Plumbing System ◽  
Volcanic Conduit ◽  
Plumbing Systems ◽  
Dimensional Reconstruction ◽  
First Time

The nature and growth of magmatic plumbing systems are of fundamental importance to igneous geology. Traditionally, magma chambers have been viewed as rapidly emplaced bodies of molten rock or partially crystallized “magma mush” connected to the surface by a narrow cylindrical conduit (referred to as the “balloon-and-straw” model). Recent data suggest, however, that magma chambers beneath volcanoes are formed incrementally through amalgamation of smaller intrusions. Here we present the first high-resolution three-dimensional reconstruction of an ancient volcanic plumbing system as a large laccolithic complex. By integrating seismic reflection and gravity data, we show that the ~200 km3 laccolith appears to have formed through partial amalgamation of smaller intrusions. The complex appears to have fed both surface volcanism and an extensive sill network beneath the volcanic edifice. Numerous sills are imaged within the volcanic conduit, indicating that magma stalled at various levels during its ascent. Our results reveal for the first time the entire multicomponent plumbing system within a large ancient shield volcano.

Australian Triassic lungfish skulls

1994 ◽  
Vol 68 (3) ◽  
pp. 647-654 ◽  
Author(s):  
A. Kemp
Keyword(s):  
New South ◽  
New South Wales ◽  
Three Dimensional ◽  
Lower Triassic ◽  
South Wales ◽  
Tooth Plate ◽  
Dimensional Reconstruction ◽  
First Time ◽  
To Receive ◽  
Australian Lungfish

Skull bones of Gosfordia truncata Woodward, 1891, from the Lower Triassic Hawkesbury Sandstone of New South Wales, Australia, are described for the first time. The skull roofing pattern suggests possible affinities between G. truncata and Paraceratodus germaini (Triassic, southwest Madagascar). A three-dimensional reconstruction of the skull of Ceratodus formosus Wade, 1935, based on the holotype, found in a Lower Triassic deposit at Brookvale in New South Wales, is included. This reconstruction indicates that this species is not closely related either to the recent Australian lungfish, Neoceratodus forsteri, or to the Triassic Ceratodus (Tellerodus) sturii from Nord Alpen in Austria, and it has no close affinities with G. truncata. A new genus, Ariguna, is therefore proposed to receive Ceratodus formosus Wade, 1935. Without associated tooth plate material, G. truncata and A. formosa cannot be defined more precisely.

scholarly journals Three-dimensional reconstruction of a whole insect reveals its phloem sap-sucking mechanism at nano-resolution

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Xin-Qiu Wang ◽  
Jian-sheng Guo ◽  
Dan-Ting Li ◽  
Yang Yu ◽  
Jaco Hagoort ◽  
...  
Keyword(s):  
Brown Planthopper ◽  
Three Dimensional ◽  
Nilaparvata Lugens ◽  
Phloem Sap ◽  
Naturally Occurring ◽  
Internal Structures ◽  
Dimensional Reconstruction ◽  
Block Face ◽  
First Time ◽  
Plant Sap

Using serial block-face scanning electron microscopy, we report on the internal 3D structures of the brown planthopper,Nilaparvata lugens(Hemiptera: Delphacidae) at nanometer resolution for the first time. Within the reconstructed organs and tissues, we found many novel and fascinating internal structures in the planthopper such as naturally occurring three four-way rings connecting adjacent spiracles to facilitate efficient gas exchange, and fungal endosymbionts in a single huge insect cell occupying 22% of the abdomen volume to enable the insect to live on plant sap. To understand the muscle and stylet movement during phloem sap-sucking, the cephalic skeleton and muscles were reconstructed in feeding nymphs. The results revealed an unexpected contraction of the protractors of the stylets and suggested a novel feeding model for the phloem sap-sucking.

Proteolytic Control of Bacteriophage HK97 Capsid Maturation.

1998 ◽  
Vol 4 (S2) ◽  
pp. 984-985
Author(s):  
Robert L. Duda ◽  
James F. Conway ◽  
Naiqian Cheng ◽  
Alasdair C. Steven ◽  
Roger W. Hendrix
Keyword(s):  
Conformational Changes ◽  
Three Dimensional ◽  
Temperate Bacteriophage ◽  
Covalent Bonds ◽  
E Coli ◽  
Cryo Electron Microscopy ◽  
Dimensional Reconstruction ◽  
Capsid Maturation ◽  
Icosahedral Capsid ◽  
Icosahedral Particle

HK97 is a tailed temperate bacteriophage of E. coli that builds an icosahedral capsid using steps that include regulated assembly, proteolysis, radical conformational changes and the formation of novel covalent bonds (Fig. 1). This pathway is being exploited as a model system to explore how the formation of multiprotein complexes can be regulated by each of these mechanisms. We have identified and purified at least four intermediates (Prohead I, Prohead II, Head I and Head II) and examined them by cryo-electron microscopy and three dimensional reconstruction procedures (Fig. 2). Comparison of particle reconstructions at resolution of about 25 - 30 A have lead to major insights into the causes and purposes of the regulated changes that we have also characterized biochemically and genetically.Prohead I consists of 420 copies of the 42 kDa gp5 capsid protein arranged as 72 blister-shaped morphological capsomers in a thick walled hollow T=7 icosahedral particle with a diameter of -470 Å.

scholarly journals Photoprotective energy dissipation is greater in the lower, not the upper, regions of a rice canopy: a 3D analysis

2020 ◽  
Vol 71 (22) ◽  
pp. 7382-7392 ◽  
Author(s):  
Chuan Ching Foo ◽  
Alexandra J Burgess ◽  
Renata Retkute ◽  
Pracha Tree-Intong ◽  
Alexander V Ruban ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Light ◽  
Photochemical Quenching ◽  
3D Analysis ◽  
Low Light ◽  
Gene Encoding ◽  
Light Intensities ◽  
Dimensional Reconstruction ◽  
Non Photochemical Quenching

Abstract High light intensities raise photosynthetic and plant growth rates but can cause damage to the photosynthetic machinery. The likelihood and severity of deleterious effects are minimised by a set of photoprotective mechanisms, one key process being the controlled dissipation of energy from chlorophyll within PSII known as non-photochemical quenching (NPQ). Although ubiquitous, the role of NPQ in plant productivity is important because it momentarily reduces the quantum efficiency of photosynthesis. Rice plants overexpressing and deficient in the gene encoding a central regulator of NPQ, the protein PsbS, were used to assess the effect of protective effectiveness of NPQ (pNPQ) at the canopy scale. Using a combination of three-dimensional reconstruction, modelling, chlorophyll fluorescence, and gas exchange, the influence of altered NPQ capacity on the distribution of pNPQ was explored. A higher phototolerance in the lower layers of a canopy was found, regardless of genotype, suggesting a mechanism for increased protection for leaves that experience relatively low light intensities interspersed with brief periods of high light. Relative to wild-type plants, psbS overexpressors have a reduced risk of photoinactivation and early growth advantage, demonstrating that manipulating photoprotective mechanisms can impact both subcellular mechanisms and whole-canopy function.

Three-Dimensional Characterization of a Pure Thermal Plume

2005 ◽  
Vol 127 (6) ◽  
pp. 624-636 ◽  
Author(s):  
Minh Vuong Pham ◽  
Fre´de´ric Plourde ◽  
Son Doan Kim
Keyword(s):  
Direct Method ◽  
Three Dimensional ◽  
Momentum Equation ◽  
Thermal Plume ◽  
Thermal Plumes ◽  
Heating Source ◽  
Entrainment Coefficient ◽  
Particle Imaging ◽  
First Time

Pure thermal plumes have been investigated by two-dimensional (2D) and three-dimensional (3D) particle imaging velocimetry (PIV) techniques. While classical plume features have been checked out, time-dependent analysis allows one to clearly detect contraction and expulsion phases which are mainly driven by turbulent structure behavior. Balance of momentum equation demonstrates the link between stronger structures and expulsion-contraction motion mainly dominated by plume engulfment during contraction phases. A ratio of 3 between entrained mass flow rate during contraction and expulsion phases has been estimated. A new method, never previously applied to pure thermal plume, allows one to accurately characterize entrainment mechanism and for the first time, the latter renders it possible to estimate the entrainment coefficient all along the plume height, even close to the heating source. Moreover, entrainment coefficient is found to be 20% higher with direct method as opposed to the classical differential one widely used in the literature. Such a huge gap is found to be due to the fluctuating density and velocity part. Even through it markedly contributes to an enhanced entrainment mechanism, the role of fluctuation was generally overlooked in the previous works devoted to entrainment coefficient estimate.

scholarly journals Exploring the Nature of Desmosomal Cadherin Associations in 3D

2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Gethin R. Owen ◽  
David L. Stokes
Keyword(s):  
Electron Tomography ◽  
Three Dimensional ◽  
Direct Consequence ◽  
Desmosomal Cadherins ◽  
Protein Molecules ◽  
Structural Interactions ◽  
Structural Differences ◽  
Physical Principles ◽  
Insight Into

Desmosomes are a complex assembly of protein molecules that mediate adhesion between adjacent cells. Desmosome composition is well established and spatial relationships between components have been identified. Intercellular cell-cell adhesion is created by the interaction of extracellular domains of desmosomal cadherins, namely, desmocollins and desmogleins. High-resolution methods have provided insight into the structural interactions between cadherins. However, there is a lack of understanding about the architecture of the intact desmosomes and the physical principles behind their adhesive strength are unclear. Electron Tomography (ET) studies have offered three-dimensional visual data of desmosomal cadherin associations at molecular resolution. This review discusses the merits of two cadherin association models represented using ET. We discuss the possible role of sample preparation on the structural differences seen between models and the possibility of adaptive changes in the structure as a direct consequence of mechanical stress and stratification.

Sign in / Sign up

Export Citation Format

Share Document