scholarly journals THERMAL ANALYSIS OF POLYANION METACHROMASY: TEMPERATURE EFFECTS ON STAINED CELLS, TISSUES AND MODELS

1969 ◽  
Vol 17 (10) ◽  
pp. 658-667 ◽  
Author(s):  
JOHN W. KELLY ◽  
LOUIS CHANG

Metachromasy of toluidine blue-stained materials was examined at 5-95°C visually and 30-70°C microspectrophotometrically. Cells and tissues provided sites of acid mucopolysaccharides and nucleic acids, which were also prepared as films and droplets. As in similar studies of aqueous solutions, metachromatic ratios were inverse, linear, reversible functions of temperature, with the possible exception of deoxyribonucleic acid. An aqueous mounting medium (gelatin) supported maximum excursions of metachromasy during heating and cooling, although reversible loss of metachromasy occurs to lesser degrees in conventional media. Removal or denaturation of cartilage matrix protein merely increased over-all metachromasy; slopes of thermal plots were unchanged. All evidence suggests that metachromasy is not a fundamentally different phenomenon in solutions and solid systems. Temperature studies emphasize the role of structured water in metachromasy, interaction of water and other solvents and particularly solvent dielectric constant in relation to dye-dye interaction. The limited literature on temperature and biologic staining is reviewed.

1990 ◽  
Vol 64 (4) ◽  
pp. 1716-1725 ◽  
Author(s):  
D Blondel ◽  
G G Harmison ◽  
M Schubert

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Amir Ata Saei ◽  
Christian M. Beusch ◽  
Pierre Sabatier ◽  
Juan Astorga Wells ◽  
Hassan Gharibi ◽  
...  

AbstractDespite the immense importance of enzyme–substrate reactions, there is a lack of general and unbiased tools for identifying and prioritizing substrate proteins that are modified by the enzyme on the structural level. Here we describe a high-throughput unbiased proteomics method called System-wide Identification and prioritization of Enzyme Substrates by Thermal Analysis (SIESTA). The approach assumes that the enzymatic post-translational modification of substrate proteins is likely to change their thermal stability. In our proof-of-concept studies, SIESTA successfully identifies several known and novel substrate candidates for selenoprotein thioredoxin reductase 1, protein kinase B (AKT1) and poly-(ADP-ribose) polymerase-10 systems. Wider application of SIESTA can enhance our understanding of the role of enzymes in homeostasis and disease, opening opportunities to investigate the effect of post-translational modifications on signal transduction and facilitate drug discovery.


2008 ◽  
Vol 295 (2) ◽  
pp. E254-E261 ◽  
Author(s):  
Shiguang Liu ◽  
Jianping Zhou ◽  
Wen Tang ◽  
Rochelle Menard ◽  
Jian Q. Feng ◽  
...  

Autosomal recessive hypophosphatemic rickets (ARHR), which is characterized by renal phosphate wasting, aberrant regulation of 1α-hydroxylase activity, and rickets/osteomalacia, is caused by inactivating mutations of dentin matrix protein 1 ( DMP1). ARHR resembles autosomal dominant hypophosphatemic rickets (ADHR) and X-linked hypophosphatemia (XLH), hereditary disorders respectively caused by cleavage-resistant mutations of the phosphaturic factor FGF23 and inactivating mutations of PHEX that lead to increased production of FGF23 by osteocytes in bone. Circulating levels of FGF23 are increased in ARHR and its Dmp1-null mouse homologue. To determine the causal role of FGF23 in ARHR, we transferred Fgf23 deficient/enhanced green fluorescent protein (eGFP) reporter mice onto Dmp1-null mice to create mice lacking both Fgf23 and Dmp1. Dmp1−/− mice displayed decreased serum phosphate concentrations, inappropriately normal 1,25(OH)2D levels, severe rickets, and a diffuse form of osteomalacia in association with elevated Fgf23 serum levels and expression in osteocytes. In contrast, Fgf23−/− mice had undetectable serum Fgf23 and elevated serum phosphate and 1,25(OH)2D levels along with severe growth retardation and focal form of osteomalacia. In combined Dmp1−/−/Fgf23−/−, circulating Fgf23 levels were also undetectable, and the serum levels of phosphate and 1,25(OH)2D levels were identical to Fgf23−/− mice. Rickets and diffuse osteomalacia in Dmp1-null mice were transformed to severe growth retardation and focal osteomalacia characteristic of Fgf23-null mice. These data suggest that the regulation of extracellular matrix mineralization by DMP1 is coupled to renal phosphate handling and vitamin D metabolism through a DMP1-dependent regulation of FGF23 production by osteocytes.


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