scholarly journals Substructure of crystalline peroxisomes in methanol-grown Hansenula polymorpha: evidence for an in vivo crystal of alcohol oxidase.

1981 ◽  
Vol 1 (10) ◽  
pp. 949-957 ◽  
Author(s):  
M Veenhuis ◽  
W Harder ◽  
J P van Dijken ◽  
F Mayer
Keyword(s):  
Osmotic Shock ◽  
Hansenula Polymorpha ◽  
Three Dimensional ◽  
Alcohol Oxidase ◽  
Molecular Architecture ◽  
Three Dimensional Model ◽  
Structural Element ◽  
Free Mobility ◽  
Crystalline Matrix

The substructural organization of completely crystalline peroxisomes present in Hansenula polymorpha cells grown under methanol limitation in a chemostat was investigated by different cytochemical and ultrastructural techniques. Time-dependent cytochemical staining experiments indicated that activities of the two main constituents of these organelles, namely, alcohol oxidase and catalase, were present throughout the crystalline matrix. Catalase was completely removed from isolated peroxisomes by osmotic shock treatment. After such treatment, the ultrastructure of the crystalline matrix of the organelles remained virtually intact. Because alcohol oxidase activity was still present in this matrix, it was concluded that alcohol oxidase protein is the only structural element of the peroxisomal crystalloids. The molecular architecture of the crystalloids was investigated in ultrathin cryosections which permitted recognition of individual molecules in the crystalline matrix. Depending on the plane of sectioning, different crystalline patterns were observed. Tilting experiments indicated that these images were caused by superposition of octameric alcohol oxidase molecules arranged in a tetragonal lattice. A three-dimensional model of the crystalloid is presented. The repeating unit of this structure is composed of four alcohol oxidase molecules. The crystalloid represents an open structure, which may explain the observed free mobility of catalase molecules.

Substructure of crystalline peroxisomes in methanol-grown Hansenula polymorpha: evidence for an in vivo crystal of alcohol oxidase

1981 ◽  
Vol 1 (10) ◽  
pp. 949-957
Author(s):  
M Veenhuis ◽  
W Harder ◽  
J P van Dijken ◽  
F Mayer
Keyword(s):  
Osmotic Shock ◽  
Hansenula Polymorpha ◽  
Three Dimensional ◽  
Alcohol Oxidase ◽  
Molecular Architecture ◽  
Three Dimensional Model ◽  
Structural Element ◽  
Free Mobility ◽  
Crystalline Matrix

The substructural organization of completely crystalline peroxisomes present in Hansenula polymorpha cells grown under methanol limitation in a chemostat was investigated by different cytochemical and ultrastructural techniques. Time-dependent cytochemical staining experiments indicated that activities of the two main constituents of these organelles, namely, alcohol oxidase and catalase, were present throughout the crystalline matrix. Catalase was completely removed from isolated peroxisomes by osmotic shock treatment. After such treatment, the ultrastructure of the crystalline matrix of the organelles remained virtually intact. Because alcohol oxidase activity was still present in this matrix, it was concluded that alcohol oxidase protein is the only structural element of the peroxisomal crystalloids. The molecular architecture of the crystalloids was investigated in ultrathin cryosections which permitted recognition of individual molecules in the crystalline matrix. Depending on the plane of sectioning, different crystalline patterns were observed. Tilting experiments indicated that these images were caused by superposition of octameric alcohol oxidase molecules arranged in a tetragonal lattice. A three-dimensional model of the crystalloid is presented. The repeating unit of this structure is composed of four alcohol oxidase molecules. The crystalloid represents an open structure, which may explain the observed free mobility of catalase molecules.

scholarly journals Effects of Shiga Toxin Type 2 on a Bioengineered Three-Dimensional Model of Human Renal Tissue

2014 ◽  
Vol 83 (1) ◽  
pp. 28-38 ◽  
Author(s):  
Teresa M. DesRochers ◽  
Erica Palma Kimmerling ◽  
Dakshina M. Jandhyala ◽  
Wassim El-Jouni ◽  
Jing Zhou ◽  
...  
Keyword(s):  
Cell Culture ◽  
Renal Failure ◽  
Shiga Toxin ◽  
Three Dimensional ◽  
Kidney Injury ◽  
Renal Tissue ◽  
Three Dimensional Model ◽  
Drug Induced ◽  
Tissue Model

Shiga toxins (Stx) are a family of cytotoxic proteins that can cause hemolytic-uremic syndrome (HUS), a thrombotic microangiopathy, following infections by Shiga toxin-producingEscherichia coli(STEC). Renal failure is a key feature of HUS and a major cause of childhood renal failure worldwide. There are currently no specific therapies for STEC-associated HUS, and the mechanism of Stx-induced renal injury is not well understood primarily due to a lack of fully representative animal models and an inability to monitor disease progression on a molecular or cellular level in humans at early stages. Three-dimensional (3D) tissue models have been shown to be morein vivo-like in their phenotype and physiology than 2D cultures for numerous disease models, including cancer and polycystic kidney disease. It is unknown whether exposure of a 3D renal tissue model to Stx will yield a morein vivo-like response than 2D cell culture. In this study, we characterized Stx2-mediated cytotoxicity in a bioengineered 3D human renal tissue model previously shown to be a predictor of drug-induced nephrotoxicity and compared its response to Stx2 exposure in 2D cell culture. Our results demonstrate that although many mechanistic aspects of cytotoxicity were similar between 3D and 2D, treatment of the 3D tissues with Stx resulted in an elevated secretion of the kidney injury marker 1 (Kim-1) and the cytokine interleukin-8 compared to the 2D cell cultures. This study represents the first application of 3D tissues for the study of Stx-mediated kidney injury.

scholarly journals Identification of Novel Recognition Motifs and Regulatory Targets for the Yeast Actin-regulating Kinase Prk1p

2003 ◽  
Vol 14 (12) ◽  
pp. 4871-4884 ◽  
Author(s):  
Bo Huang ◽  
Guisheng Zeng ◽  
Alvin Y.J. Ng ◽  
Mingjie Cai
Keyword(s):  
Actin Cytoskeleton ◽  
Phosphorylation Site ◽  
Three Dimensional ◽  
Kinase Domain ◽  
Yeast Genome ◽  
Three Dimensional Model ◽  
Recognition Sequence ◽  
Yeast Saccharomyces Cerevisiae

Prk1p is a serine/threonine kinase involved in the regulation of the actin cytoskeleton organization in the yeast Saccharomyces cerevisiae. Previously, we have identified LxxQxTG as the phosphorylation site of Prk1p. In this report, the recognition sequence for Prk1p is investigated more thoroughly. It is found that the presence of a hydrophobic residue at the position of P-5 is necessary for Prk1p phosphorylation and L, I, V, and M are all able to confer the phosphorylation at various efficiencies. The residue flexibility at P-2 has also been identified to include Q, N, T, and S. A homology-based three-dimensional model of the kinase domain of Prk1p provided some structural interpretations for these substrate specificities. The characterization of the [L/I/V/M]xx[Q/N/T/S]xTG motif led to the identification of a spectrum of potential targets for Prk1p from yeast genome. One of them, Scd5p, which contains three LxxTxTG motifs and is previously known to be important for endocytosis and actin organization, has been chosen to demonstrate its relationship with Prk1p. Phosphorylation of Scd5p by Prk1p at the three LxxTxTG motifs could be detected in vitro and in vivo, and deletion of PRK1 suppressed the defects in actin cytoskeleton and endocytosis in one of the scd5 mutants. These results allowed us to conclude that Scd5p is likely another regulatory target of Prk1p.

scholarly journals Mutagenesis and Molecular Modeling Reveal Three Key Extracellular Loops of the Membrane Receptor HasR That Are Involved in Hemophore HasA Binding

2007 ◽  
Vol 189 (14) ◽  
pp. 5379-5382 ◽  
Author(s):  
Clément Barjon ◽  
Karine Wecker ◽  
Nadia Izadi-Pruneyre ◽  
Philippe Delepelaire
Keyword(s):  
Molecular Modeling ◽  
Outer Membrane ◽  
Three Dimensional ◽  
Membrane Receptor ◽  
Dimensional Model ◽  
Outer Membrane Receptor ◽  
Three Dimensional Model ◽  
Extracellular Loops

ABSTRACT On the basis of the three-dimensional model of the heme/hemophore TonB-dependent outer membrane receptor HasR, mutants with six-residue deletions in the 11 putative extracellular loops were generated. Although all mutants continued to be active TonB-dependent heme transporters, mutations in three loops abolished hemophore HasA binding both in vivo and in vitro.

In vivo inactivation of peroxisomal alcohol oxidase in Hansenula polymorpha by KCN is an irreversible process

1988 ◽  
Vol 151 (1) ◽  
pp. 26-33 ◽  
Author(s):  
Ida J. van der Klei ◽  
Marten Veenhuis ◽  
Klaas Nicolay ◽  
Wim Harder
Keyword(s):  
Irreversible Process ◽  
Hansenula Polymorpha ◽  
Alcohol Oxidase

scholarly journals 3D-Analysis of a non-planispiral ammonoid from the Hunsrück Slate: natural or pathological variation?

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3526 ◽  
Author(s):  
Julia Stilkerich ◽  
Trisha A. Smrecak ◽  
Kenneth De Baets
Keyword(s):  
Three Dimensional ◽  
Euphotic Zone ◽  
Type Specimen ◽  
3D Analysis ◽  
Three Dimensional Model ◽  
Hunsrück Slate ◽  
Early Devonian ◽  
Holotype Specimen ◽  
New Type

We herein examine the only known non-planispirally coiled early Devonian ammonoid, the holotype specimen of Ivoites opitzi, to investigate if the host was encrusted in vivo and if these sclerobionts were responsible for the trochospiral coiling observed in this unique specimen. To test if the presence of runner-like sclerobionts infested the historically collected specimen of Ivoites opitzi during its life, we used microCT to produce a three-dimensional model of the surface of the specimen. Our results indicate that sclerobionts grew across the outer rim (venter) on both sides of the ammonoid conch at exactly the location where the deviation from the planispiral was recognized, and where subsequent ammonoid growth would likely preclude encrustation. This indicates in vivo encrustation of the I. opitzi specimen, and represents the earliest documentation of the phenomenon. Further, this suggests that non-planispiral coiling in I. opitzi was likely pathologically induced and does not represent natural morphological variation in the species. Despite the observed anomalies in coiling, the specimen reached adulthood and retains important identifying morphological features, suggesting the ammonoid was minimally impacted by encrustation in life. As such, appointing a new type specimen—as suggested by some authors—for the species is not necessary. In addition, we identify the sclerobionts responsible for modifying the coiling of this specimen as hederelloids, a peculiar group of sclerobionts likely related to phoronids. Hederelloids in the Devonian are commonly found encrusting on fossils collected in moderately deep environments within the photic zone and are rarely documented in dysphotic and aphotic samples. This indicates that when the ammonoid was encrusted it lived within the euphotic zone and supports the latest interpretations of the Hunsrück Slate depositional environment in the Bundenbach-Gemünden area.

Finite Element Modeling of Knee Joint Contact Pressures and Comparison to Magnetic Resonance Imaging of the Loaded Knee

2003 ◽  
Author(s):  
Jiang Yao ◽  
Art D. Salo ◽  
Monica Barbu-McInnis ◽  
Amy L. Lerner
Keyword(s):  
Magnetic Resonance Imaging ◽  
Finite Element ◽  
Magnetic Resonance ◽  
Knee Joint ◽  
Material Properties ◽  
Three Dimensional ◽  
Resonance Imaging ◽  
Three Dimensional Model ◽  
Model Predictions

A finite element model of the knee joint could be helpful in providing insight on mechanisms of injury, effects of treatment, and the role of mechanical factors in degenerative conditions. However, preparation of such a model involves many geometric simplifications and input of material properties, some of which are poorly understood. Therefore, a method to compare model predictions to actual behaviors under controlled conditions could provide confidence in the model before exploration of other loading scenarios. Our laboratory has developed a method to apply axial loads to the in vivo human knee during magnetic resonance imaging, resembling weightbearing conditions. Image processing algorithms may then be used to assess the three-dimensional kinematics of the tibia and femur during loading. A three-dimensional model of the tibio-menisco-femoral contact has been generated and the image-based kinematic boundary conditions were applied to investigate the distribution of stresses and strains in the articular cartilage and menisci throughout the loading period. In this study, our goal is to investigate the contact patterns during long term loading of up to twenty minutes in the healthy knee. Specifically, we assess the use of both elastic and poroelastic material properties in the cartilage, and compare model predictions to known loading conditions and images of tissue deformations.

In vivo inactivation of alcohol oxidase in hansenula polymorpha

1988 ◽  
Vol 24 (4) ◽  
pp. 439
Author(s):  
I.J. van der Klei ◽  
M. Veenhuis ◽  
W. Harder
Keyword(s):  
Hansenula Polymorpha ◽  
Alcohol Oxidase

scholarly journals Recent Advances in Three-Dimensional Multicellular Spheroid Culture and Future Development

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 96
Author(s):  
Honglin Shen ◽  
Shuxiang Cai ◽  
Chuanxiang Wu ◽  
Wenguang Yang ◽  
Haibo Yu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Multicellular Spheroids ◽  
Three Dimensional Model ◽  
Advantages And Disadvantages ◽  
High Throughput Drug Screening ◽  
Tumor Research ◽  
Basic Biology ◽  
And Function

Three-dimensional multicellular spheroids (MCSs) have received extensive attention in the field of biomedicine due to their ability to simulate the structure and function of tissues in vivo more accurately than traditional in vitro two-dimensional models and to simulate cell–cell and cell extracellular matrix (ECM) interactions. It has become an important in vitro three-dimensional model for tumor research, high-throughput drug screening, tissue engineering, and basic biology research. In the review, we first summarize methods for MCSs generation and their respective advantages and disadvantages and highlight the advances of hydrogel and microfluidic systems in the generation of spheroids. Then, we look at the application of MCSs in cancer research and other aspects. Finally, we discuss the development direction and prospects of MCSs

Sign in / Sign up

Export Citation Format

Share Document