scholarly journals The in vacuo release of Ar from minerals: 2. The role of structural modifications of K-feldspar during heating revealed by Raman microprobe analyses

2021 ◽  
pp. 120382
Author(s):  
Jennifer Kung ◽  
Igor M. Villa
Keyword(s):  
Structural Modifications ◽  
Raman Microprobe

scholarly journals Exploring Secondary Metabolite Profiles of Stachybotrys spp. by LC-MS/MS

Toxins ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 133 ◽  
Author(s):  
Annika Jagels ◽  
Viktoria Lindemann ◽  
Sebastian Ulrich ◽  
Christoph Gottschalk ◽  
Benedikt Cramer ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Future Research ◽  
Structural Modifications ◽  
Metabolite Profiles ◽  
The Individual ◽  
First Time ◽  
Analytical Standards ◽  
Respective Species

The genus Stachybotrys produces a broad diversity of secondary metabolites, including macrocyclic trichothecenes, atranones, and phenylspirodrimanes. Although the class of the phenylspirodrimanes is the major one and consists of a multitude of metabolites bearing various structural modifications, few investigations have been carried out. Thus, the presented study deals with the quantitative determination of several secondary metabolites produced by distinct Stachybotrys species for comparison of their metabolite profiles. For that purpose, 15 of the primarily produced secondary metabolites were isolated from fungal cultures and structurally characterized in order to be used as analytical standards for the development of an LC-MS/MS multimethod. The developed method was applied to the analysis of micro-scale extracts from 5 different Stachybotrys strains, which were cultured on different media. In that process, spontaneous dialdehyde/lactone isomerization was observed for some of the isolated secondary metabolites, and novel stachybotrychromenes were quantitatively investigated for the first time. The metabolite profiles of Stachybotrys species are considerably influenced by time of growth and substrate availability, as well as the individual biosynthetic potential of the respective species. Regarding the reported adverse effects associated with Stachybotrys growth in building environments, combinatory effects of the investigated secondary metabolites should be addressed and the role of the phenylspirodrimanes re-evaluated in future research.

Neural induction and the structure of the target cell surface

Development ◽  
1982 ◽  
Vol 70 (1) ◽  
pp. 171-187
Author(s):  
A. M. Duprat ◽  
L. Gualandris ◽  
P. Rouge
Keyword(s):  
Cell Surface ◽  
Structural Integrity ◽  
Neural Induction ◽  
Active Role ◽  
Target Cells ◽  
Similar Treatment ◽  
Structural Modifications ◽  
Pleurodeles Waltl

Lectins (SBA and PSA) were used to provoke crowding and structural modifications of the presumptive ectoderm cell surface in order to investigate the role of the membrane organization of the competent target cells in neural induction. Are specific characteristics of the cell surface essential for this phenomenon to occur? From amphibian gastrulae, it is possible to obtain neural induction in vitro by association of presumptive ectoderm (target cells) with chordamesoderm (inductor tissue): 4 h of contact is sufficient in Pleurodeles waltl for transmission of the inductive signal. Very quickly, the treatment of the normal ectoderm by lectins (SBA-FITC or PSA-FITC) provoked surface modifications. Lectin-treatment (50 µg ml1−, 30 min) of presumptive ectoderm did not result in any neural induction. Lectin-treatment (50 µg ml1−, 30 min) of presumptive ectoderm previous to its association with the natural inductor for 4 h, disturbed the phenomenon: no induction. Similar treatment followed by association with the inductor for 24 h: induction. Treatment of SBA or PSA with their respective hapten inhibitors prior to addition to ectodermal cells completely blocked the suppressive effects on induction. The structural integrity of the membrane of competent target cells is necessary for neural induction to occur. The cell membrane could thus play, directly or indirectly, an active role in the specificity of this process

scholarly journals Mn12 single molecule magnets deposited on μ-SQUID sensors: the role of interphases and structural modifications

Nanoscale ◽  
2013 ◽  
Vol 5 (24) ◽  
pp. 12565 ◽  
Author(s):  
Elena Bellido ◽  
Pablo González-Monje ◽  
Ana Repollés ◽  
Mark Jenkins ◽  
Javier Sesé ◽  
...  
Keyword(s):  
Single Molecule ◽  
Single Molecule Magnets ◽  
Structural Modifications

On the Role of Tumor Cell Surface in the Accumulation of Radioisotopes

1976 ◽  
Vol 15 (05) ◽  
pp. 242-245 ◽  
Author(s):  
R. Dermietzel ◽  
M. Heidbreder ◽  
L. J. Anghileri
Keyword(s):  
Cell Surface ◽  
Tumor Cell ◽  
Cell Membrane Permeability ◽  
Ascites Tumor ◽  
Cell Coat ◽  
Structural Modifications ◽  
Permeability Changes ◽  
Cell Surface Changes ◽  
Surface Changes

SummaryThe effects of electrical charge and structural modifications of the ascites tumor cell surface on the uptake of several radiocompounds have been investigated. Changes in its electrical surface charge provoke variations in the radioactivity incorporation which appear to be selective for chelated or ionic radioisotopes. The release of a part of the cell “coat” by EDTA affects profoundly the incorporation of radioisotopes in a process which seems to be related to cell membrane permeability changes. The relationships between cell surface changes and radiocompounds accumulation are discussed.

Biological Function of Changes in RNA Metabolism in Plant Adaptation to Abiotic Stress

2019 ◽  
Vol 60 (9) ◽  
pp. 1897-1905 ◽  
Author(s):  
Akihiro Matsui ◽  
Kentaro Nakaminami ◽  
Motoaki Seki
Keyword(s):  
Gene Expression ◽  
Abiotic Stress ◽  
Metabolic Regulation ◽  
Rna Stability ◽  
Rna Metabolism ◽  
Stress Adaptation ◽  
Transcriptional Level ◽  
Related Gene ◽  
Structural Modifications

Abstract Plant growth and productivity are greatly impacted by environmental stresses. Therefore, plants have evolved various sophisticated mechanisms for adaptation to nonoptimal environments. Recent studies using RNA metabolism-related mutants have revealed that RNA processing, RNA decay and RNA stability play an important role in regulating gene expression at a post-transcriptional level in response to abiotic stresses. Studies indicate that RNA metabolism is a unified network, and modification of stress adaptation-related transcripts at multiple steps of RNA metabolism is necessary to control abiotic stress-related gene expression. Recent studies have also demonstrated the important role of noncoding RNAs (ncRNAs) in regulating abiotic stress-related gene expression and revealed their involvement in various biological functions through their regulation of DNA methylation, DNA structural modifications, histone modifications and RNA–RNA interactions. ncRNAs regulate mRNA transcription and their synthesis is affected by mRNA processing and degradation. In the present review, recent findings pertaining to the role of the metabolic regulation of mRNAs and ncRNAs in abiotic stress adaptation are summarized and discussed.

scholarly journals A new family of urea-based low molecular-weight organogelators for environmental remediation: the influence of structure

Soft Matter ◽  
2018 ◽  
Vol 14 (43) ◽  
pp. 8821-8827 ◽  
Author(s):  
William J. Peveler ◽  
Hollie Packman ◽  
Shirin Alexander ◽  
Raamanand R. Chauhan ◽  
Lilian M. Hayes ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Environmental Remediation ◽  
Low Molecular Weight ◽  
Structural Modifications ◽  
New Family ◽  
Low Molecular Weight Organogelators

Six analogous low molecular weight organogelators are comprehensively characterised to investigate the role of small structural modifications on performance.

Role of Epithelial Cells in Initiation and Propagation of Intestinal Inflammation. Eliminating the static: tight junction dynamics exposed

2006 ◽  
Vol 290 (4) ◽  
pp. G577-G582 ◽  
Author(s):  
Le Shen ◽  
Jerrold R. Turner
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Tight Junctions ◽  
Plasma Membranes ◽  
Intestinal Inflammation ◽  
Intestinal Barrier ◽  
Barrier Properties ◽  
Structural Modifications ◽  
Mucosal Surfaces

Like all mucosal surfaces, the intestine forms a barrier that separates the external environment, i.e., the gut lumen, from the protected internal milieu. The intestinal barrier is formed by the epithelial cells that line the luminal surface. Plasma membranes of these cells prevent free passage of hydrophilic molecules across this barrier but do not seal the space between cells. This function is provided by the tight junction. Each cell is encircled at the apicolateral boundary by the tight junction, which seals the paracellular space. The tight junction does not form a completely impermeant seal, however, because that would prevent paracellular absorption of essential nutrients and ions; intestinal tight junctions are “leaky” and allow solutes to be transported paracellularly according to size and charge. Abundant data are available to demonstrate that barrier properties of tight junctions can be modulated in response to physiological, pharmacological, and pathophysiological stimuli, but the structural modifications responsible for these responses are poorly defined. Recent advances in understanding the role of tight junction dynamics in response to such stimuli are the focus of this review.

scholarly journals More than a feeling: microscopy approaches to understanding surface-sensing mechanisms

2020 ◽  
Author(s):  
Katherine J. Graham ◽  
Lori L. Burrows
Keyword(s):  
Live Cells ◽  
Surface Attachment ◽  
Bacterial Surface ◽  
Structural Modifications ◽  
Structure And Dynamics ◽  
Type Iv ◽  
Surface Sensing ◽  
Two Component Signal Transduction ◽  
Sense And Respond

The mechanisms by which bacteria sense and respond to surface attachment have long been a mystery. Our understanding of the structure and dynamics of bacterial appendages, notably type IV pili (T4P), provided new insights into the potential ways that bacteria sense surfaces. T4P are ubiquitous, retractable hair-like adhesins that until recently were difficult to image in the absence of fixation due to their nanoscale size. This review focuses on recent microscopy innovations used to visualize T4P in live cells to reveal the dynamics of their retraction and extension. We discuss recently proposed mechanisms by which T4P facilitate bacterial surface sensing, including the role of surface-exposed PilY1, two-component signal transduction pathways, force-induced structural modifications of the major pilin, and altered dynamics of the T4P motor complex.

Possible involvement ofPseudomonas fluorescensand Bacillaceae in structural modifications ofTuber borchiifruit bodies

2001 ◽  
Vol 47 (3) ◽  
pp. 264-268 ◽  
Author(s):  
Barbara Citterio ◽  
Manuela Malatesta ◽  
Serafina Battistelli ◽  
Francesco Marcheggiani ◽  
Wally Baffone ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Bacterial Population ◽  
Cellulolytic Bacteria ◽  
Tuber Borchii ◽  
Structural Modifications ◽  
Early Maturation ◽  
Intimate Association ◽  
Maturation Stages ◽  
Decomposition Stages

Previous studies on Tuber borchii fruit bodies in early maturation stages suggested a role of bacteria in sporocarp structural modifications. In order to verify this hypothesis, in the present study we investigated by means of microbial and ultrastructural approaches, the bacterial population of T. borchii sporocarps from intermediate maturation phases to advanced decomposition stages, paying particular attention to chitinolytic and cellulolytic bacteria and to their relationships with ascii and ascospores. We found that Pseudomonas fluorescens and spore-forming Bacillaceae, both able to degrade cellulose and chitin, are present inside the sporocarps in all maturation stages investigated. Moreover, rod-shaped bacteria seem able to erode ascus walls and colonize the interior of ascii containing mature spores. These results suggest a possible role of these bacteria in the process of ascus opening. Moreover, the presence of P. fluorescens and Bacillaceae on isolated mature spores after decontamination suggests an intimate association between these bacteria and the ascospores.Key words: bacteria, cellulose, chitin, ectomycorrhiza.

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