scholarly journals Characterization of Optimal Strain, Frequency and Duration of Mechanical Loading on Skeletal Myotubes' Biological Responses

In Vivo ◽  
2020 ◽  
Vol 34 (4) ◽  
pp. 1779-1788 ◽  
Author(s):  
ATHANASIOS MOUSTOGIANNIS ◽  
ANASTASSIOS PHILIPPOU ◽  
EVANGELOS ZEVOLIS ◽  
ORJONA TASO ◽  
ANTONIOS CHATZIGEORGIOU ◽  
...  
Author(s):  
Suzanne Ferreri ◽  
Bing Hu ◽  
Yi-Xian Qin

Evaluation of bone’s response to mechanical loading is of critical importance in studies addressing the overall efficacy of therapeutic interventions. Moreover, thorough characterization of bone’s response to applied loads should reflect the contributions of both bone mineral (elastic properties) and collagen (viscoelastic properties).


Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1030
Author(s):  
Kevin Schneider ◽  
Benedikt Venn ◽  
Timo Mühlhaus

The objective of gene set enrichment analysis (GSEA) in modern biological studies is to identify functional profiles in huge sets of biomolecules generated by high-throughput measurements of genes, transcripts, metabolites, and proteins. GSEA is based on a two-stage process using classical statistical analysis to score the input data and subsequent testing for overrepresentation of the enrichment score within a given functional coherent set. However, enrichment scores computed by different methods are merely statistically motivated and often elusive to direct biological interpretation. Here, we propose a novel approach, called Thermodynamically Motivated Enrichment Analysis (TMEA), to account for the energy investment in biological relevant processes. Therefore, TMEA is based on surprisal analysis, which offers a thermodynamic-free energy-based representation of the biological steady state and of the biological change. The contribution of each biomolecule underlying the changes in free energy is used in a Monte Carlo resampling procedure resulting in a functional characterization directly coupled to the thermodynamic characterization of biological responses to system perturbations. To illustrate the utility of our method on real experimental data, we benchmark our approach on plant acclimation to high light and compare the performance of TMEA with the most frequently used method for GSEA.


2004 ◽  
Vol 08 (01) ◽  
pp. 1-12 ◽  
Author(s):  
Andrea L. Clark ◽  
Linda Mills ◽  
David A Hart ◽  
Walter Herzog

Mechanical loading of articular cartilage affects the synthesis and degradation of matrix macromolecules. Much of the work in this area has involved mechanical loading of articular cartilage explants or cells in vitro and assessing biological responses at the mRNA and protein levels. In this study, we developed a new experimental technique to load an intact patellofemoral joint in vivo using muscle stimulation. The articular cartilages were cyclically loaded for one hour in a repeatable and measurable manner. Cartilage was harvested from central and peripheral regions of the femoral groove and patella, either immediately after loading or after a three hour recovery period. Total RNA was isolated from the articular cartilage and biological responses were assessed on the mRNA level using the reverse transcriptase-polymerase chain reaction. Articular cartilage from intact patellofemoral joints demonstrated heterogeneity at the mRNA level for six of the genes assessed independent of the loading protocol. Cyclical loading of cartilage in its native environment led to alterations in mRNA levels for a subset of molecules when assessed immediately after the loading period. However, the increases in TIMP-1 and decreases in bFGF mRNA levels were transient; being present immediately after load application but not after a three hour recovery period.


2013 ◽  
Vol 41 (1) ◽  
pp. 166-171 ◽  
Author(s):  
Marta Busnelli ◽  
Erika Peverelli ◽  
Giovanna Mantovani ◽  
Anna Spada ◽  
Bice Chini

Receptor coupling to different G-proteins and β-arrestins has been described for a number of GPCRs (G-protein-coupled receptors), suggesting a multi-state model of receptor activation in which each receptor can assume a number of different active conformations, each capable of promoting the coupling to a specific effector. Consistently, functional-selective ligands and biased agonists have been described to be able to induce and/or stabilize only a subset of specific active conformations. Furthermore, GPCR mutants deficient in selective coupling have been reported. Functional selective ligands and receptor mutants thus constitute unique tools to dissect the specific roles of different effectors, in particular among the Gi/o family. In the present mini-review, we focus on (i) the identification of functional selective OXT (oxytocin)-derived peptides capable of activating single Gi/o isoforms, namely Gi1 or Gi3; and (ii) the characterization of an SS (somatostatin) receptor SST5 mutant selectively impaired in its GoA coupling. These analogues and receptor mutants represent unique tools for examining the contribution of Gi/o isoforms in complex biological responses and open the way for the development of drugs with peculiar selectivity profiles.


Author(s):  
Ranjana Pathak ◽  
Aruppillai Suthaparan

The cryptochrome/photolyase family (CPF) consists of a diversified class of flavoproteins that are evolutionarily related. Although their domain architecture is highly conserved, they perform entirely different physiological functions. Previous studies have confirmed the presence of a functional photolyase in Pseudoidium neolycopersici, which repairs UV-C-induced DNA damage by using near UV-A/blue light as an energy source. Similar doses of UV-C treatment followed by incubation with dark or blue light was tested on conidia germination of five isolates of P. neolycopersici collected from different regions of Norway and the Netherlands. The results showed variations in the effect of UV on germination and germination recovery under blue light incubation after UV treatment. Evolutionary studies confirmed that P. neolycopersici photolyase is highly conserved among different isolates of P. neolycopersici and among different species. All CPF members have a core domain consisting of an identical cofactor Flavin adenine dinucleotide (FAD), and an additional photoantenna chromophore. An amino acid sequence analysis demonstrated that CPF members have highly conserved C-terminals compared with their N-terminals, as FAD binds in the C-terminal region. When compared with other CPF members, varying lengths of N- and C-terminals were noticed in P. neolycopersici photolyase and putative cryptochrome, respectively. Further research using comparative genomics targeting pyrimidine base composition, the role of regulatory elements including promotor architecture, and the characterization of optical properties of native photolyase among isolates may help to explain the differences in the biological responses of conidia germination of P. neolycopersici treated with UV.


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