scholarly journals Changing the shape of hair with keratin peptides

RSC Advances ◽  
2017 ◽  
Vol 7 (81) ◽  
pp. 51581-51592 ◽  
Author(s):  
C. F. Cruz ◽  
M. Martins ◽  
J. Egipto ◽  
H. Osório ◽  
A. Ribeiro ◽  
...  
Keyword(s):  
Reducing Agents ◽  
Alkaline Ph ◽  
Neutral Ph ◽  
Disulphide Bonds

Here we propose a solution which will replace harsh reducing agents at alkaline pH by peptide formulations acting at neutral pH to change hair shape through the re-conformation of disulphide bonds.

scholarly journals Photodegradation of fluoroquinolones in aqueous solution under light conditions relevant to surface waters, toxicity assessment of photoproduct mixtures.

2021 ◽  
Author(s):  
Sarka Klementova ◽  
Martina Poncarová ◽  
Helena Langhansová ◽  
Jaroslava Lieskovská ◽  
David Kahoun ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Antibacterial Activity ◽  
Surface Waters ◽  
Ph Value ◽  
Reaction System ◽  
Photochemical Degradation ◽  
Alkaline Ph ◽  
Light Conditions ◽  
E Coli ◽  
Neutral Ph

Abstract Photochemical degradation of fluoroquinolones ciprofloxacin, enrofloxacin and norfloxacin in aqueous solution under light conditions relevant to surface waters at neutral and alkaline pH was found to proceed readily with half-lives between 0.9 and 2.7 min. The products of photochemical degradation identified by HPLC-MS included defluorinated, hydroxylated, and decarboxylated structures as well as structures with opened cyclic structures. For all of the studied substances, the reaction pathways were influenced significantly by the pH of the reaction system, with more products formed at alkaline pH than at neutral pH: the ratios of products in neutral and alkaline pH were 16/26, 9/19, 15/23 for ciprofloxacin, enrofloxacin, and norfloxacin, respectively. The structures of photoproducts and pathways of photochemical degradation are proposed. The antibacterial activities of photoproduct mixtures tested on E. coli and S. epidermidis were significantly higher in comparison to parental antibiotics in the case of both ciprofloxacin and enrofloxacin with p-values less than 0.0001 in most cases. The effect of the photoproducts was shown to be dependent on the pH value of the original antibiotic solutions before photodegradation: for ciprofloxacin, antibacterial activity against E. coli was more notably pronounced with regard to neutral pH photoproducts, while a less significant, or in one case not significant, effect of pH was observed against S. epidermidis ; for norfloxacin, antibacterial activity against both E. coli and S. epidermidis were especially high with regard to alkaline pH photoproducts

pH of Medicated Syrups–Does It Really Matter? – An in-vitro Study: Part-II

2008 ◽  
Vol 33 (2) ◽  
pp. 137-142 ◽  
Author(s):  
KL Girish Babu ◽  
Kavita Rai ◽  
Amitha Hegde
Keyword(s):  
Atomic Absorption ◽  
In Vitro Study ◽  
Vitro Study ◽  
Atomic Absorption Spectrometer ◽  
Alkaline Ph ◽  
Time Intervals ◽  
Neutral Ph ◽  
Absorption Spectrometer ◽  
Dissolution Potential

The aim of the present in vitro study was to quantify the endogenous erosive potential of the various pediatric liquid medicaments by measuring the calcium dissolution of primary enamel after immersing it for different time intervals (1min, 10 min and 8 hours) using atomic absorption spectrometer (AAS). The eight commonly used pediatric liquid medicaments which were selected had definitive endogenous calcium dissolution potential. All the medicaments showed calcium dissolution of primary enamel at alkaline pH and near neutral pH. The calcium dissolution potential of pediatric liquid medicaments when compared with their respective pH showed no statistically significant correlation. In conclusion, there was evidence of calcium dissolution from all the pediatric liquid medicaments.

scholarly journals PROTEOLYTIC ENZYMES

1946 ◽  
Vol 29 (4) ◽  
pp. 219-247 ◽  
Author(s):  
David Grob
Keyword(s):  
Proteolytic Enzymes ◽  
Reducing Agents ◽  
Sulfhydryl Groups ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Oxidizing Agents ◽  
Neutral Ph ◽  
Oxidation Reduction ◽  
Antiproteolytic Activity ◽  
Sulfhydryl Compounds

1. The literature on conditions affecting the activity of proteolytic enzymes has been reviewed. 2. Experimental data on the control of the activity of trypsin, leucoprotease, papain, serum antiprotease, leucopeptidase, and pancreatic peptidase have been presented. These data indicate that: (a) The polymorphonuclearleucocytes of the cat contain abundant proteinase and peptidase active at neutral pH; those of the rabbit lack proteinase active at neutral pH. (b) Reducing agents, including several biologically important thiol-sulfhydryl compounds and ascorbic acid, inhibit the activity of leucoprotease and trypsin. For each reductant the degree of inhibition is proportional to the reducing capacity of the medium. (c) p-Aminobenzoic acid, sulfonamides (especially sulfathiazole), and many diphenyl sulfones inhibit the activity of leucoprotease. (d) Serum, plasma, several heavy metals, ammonium salts, asparagine, thiourea, heparin, glutamic acid, tyrothricin, calcium chloride, and bile salts and bile acids also inhibit the activity of leucoprotease, and in most cases of trypsin too. (e) Preparations of tryptic digests of proteins, and egg white trypsin inhibitor, inhibit trypsin to a much greater degree than leucoprotease. (f) Mild oxidizing agents increase the activity of leucoprotease and trypsin. (g) Oxidizing agents and some inhibitors of sulfhydryl groups inhibit the antiproteolytic activity of the serum. It is suggested that serum antiprotease may consist (chiefly) of reducing agents, including thiol-sulfhydryl peptides which exert their antiproteolytic activity by virtue of the presence of sulfhydryl groups. (h) The antiproteolytic activity of the serum is progressively weakened by exposure to a hydrogen ion concentration below pH 6.5 or above pH 9.7. Because of this the pH optima of leucoprotease and trypsin are shifted in the presence of serum from pH of 7 and 8 to pH of 6 to 6.5, and the range of activity of these enzymes is slightly widened, in both acid and alkaline reactions. (i) Reducing agents increase the activity of leucopeptidase and pancreatic peptidase. Serum, sulfathiazole, and thiourea have little or no effect. 3. The significance of the oxidation-reduction system in the control of the activity of leucoprotease, trypsin, serum antiprotease, leucopeptidase, and pancreatic peptidase has been emphasized.

scholarly journals Involvement of disulphide bonds in the renal sodium/phosphate co-transporter NaPi-2

1997 ◽  
Vol 323 (2) ◽  
pp. 401-408 ◽  
Author(s):  
Yansen XIAO ◽  
Christian J.-C. BOYER ◽  
Éric VINCENT ◽  
André DUGRÉ ◽  
Vincent VACHON ◽  
...  
Keyword(s):  
Sodium Phosphate ◽  
Polyclonal Antibodies ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Reducing Agents ◽  
Western Blots ◽  
Disulphide Bonds ◽  
Reducing Conditions ◽  
Renal Brush Border Membrane ◽  
Radiation Induced

The rat renal brush border membrane sodium/phosphate co-transporter NaPi-2 was analysed in Western blots with polyclonal antibodies raised against its N-terminal and C-terminal segments. Under reducing conditions, proteins of 45–49 and 70–90 kDa (p45 and p70) were detected with N-terminal antibodies, and proteins of 40 and 70–90 kDa (p40 and p70) were detected with C-terminal antibodies. p40 and p45 apparently result from a post-translational cleavage of NaPi-2 but remain linked through one or more disulphide bonds. Glycosidase digestion showed that both polypeptides are glycosylated; the cleavage site could thus be located between Asn-298 and Asn-328, which have been shown to constitute the only two N-glycosylated residues in NaPi-2. In the absence of reducing agents, both N-terminal and C-terminal antibodies detected p70 and a protein of 180 kDa (p180), suggesting the presence of p70 dimers. Much higher concentrations of β-mercaptoethanol were required to produce a given effect in intact membrane vesicles than in solubilized proteins, indicating that the affected disulphide bonds are not exposed at the surface of the co-transporter. Phosphate transport activity decreased with increasing concentrations of reducing agents [β-mercaptoethanol, dithiothreitol and tris-(2-carboxyethyl)phosphine] and was linearly correlated with the amount of p180 detected. The target sizes estimated from the radiation-induced loss of intensity of p40, p70 and p180 were all approx. 190 kDa, suggesting that NaPi-2 exists as an oligomeric protein in which the subunits are sufficiently close to one another to allow substantial energy transfer between the monomers. When protein samples were pretreated with β-mercaptoethanol [2.5% and 5% (v/v) to optimize the detection of p40 and p70] before irradiation, target sizes estimated from the radiation-induced loss of intensity of p40 and p70 were 74 and 92 kDa respectively, showing the presence of disulphide bridges in the molecular structure of NaPi-2.

scholarly journals Influence of water pH in the hepato- and nephrotoxicity of chronic cadmium poisoning in Wistar rats

2021 ◽  
Vol 10 (9) ◽  
pp. e12210917753
Author(s):  
Daniel José Pimentel Bonfim ◽  
Fernanda Maria Garcia ◽  
Cecília Braga Laposy ◽  
Rogério Giuffrida ◽  
Gisele Alborghetti Nai ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Drinking Water ◽  
Cadmium Chloride ◽  
Albino Rats ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Hydropic Degeneration ◽  
Neutral Ph ◽  
Cadmium Poisoning ◽  
Water Ph

Introduction: Cadmium is a heavy metal found in the environment that is used industrially; however, it also causes hepato- and nephrotoxic effects. Objective: To evaluate the effect of drinking water pH on the hepato- and nephrotoxicity caused by chronic cadmium poisoning. Material and Methods: We used 90 adult, male Wistar albino rats divided into 6 groups (n = 15): GC5 received a solution of cadmium chloride in drinking water with an acidic pH (pH 5.0); GC7 received a solution of cadmium chloride (400 mg/L) in drinking water with a neutral pH (pH 7.0 water); GC8 received a solution of cadmium chloride in water with an alkaline pH (pH 8.0); GWC5 received drinking water with an acidic pH (pH 5.0); GWC7 received drinking water with a neutral pH (pH 7.0); GWC8 received drinking water with an alkaline pH (pH 8.0). The animals were euthanized 6 months after the start of the experiment. We performed tests for hepatic and renal function and conducted liver and renal histopathology. Results: Water with an acidic pH caused alterations in ALP, ALT and urea in animals exposed to cadmium (P<0.05). In the liver, the majority of animals from the GC7 (57.1%) and GC5 (53.3%) groups showed diffuse microvesicular steatosis, while other groups showed no steatosis (P>0.05). In the kidney, the majority of animals from the GC7 (78.6%) and GWC5 (71.4%) groups showed tubular hydropic degeneration; however, these data were only statistically different from the GWC7 group (P<0.05). Conclusion: Exposure to cadmium in water with an acidic pH led to higher elevations of serum ALP, AST and urea, suggesting that the pH of drinking water influences the hepato- and nephrotoxic effects of this heavy metal.

scholarly journals ON THE RECONSTITUTION OF THE CRYSTALLINE COMPONENTS OF THE SEA URCHIN FERTILIZATION MEMBRANE

1970 ◽  
Vol 45 (3) ◽  
pp. 606-614 ◽  
Author(s):  
Joseph Bryan
Keyword(s):  
Ionic Strength ◽  
Sea Urchin ◽  
Divalent Cations ◽  
Reducing Agents ◽  
Alkaline Ph ◽  
Mitotic Apparatus ◽  
Fertilization Membrane ◽  
Crystalline Component ◽  
Tubular Components

The characteristics of the reconstitution of a crystalline component of the sea urchin fertilization membrane are presented. The reassembly of large aggregates of cylindrical or tubular components is effected by the addition of calcium or other divalent cations. The reassembly requires a slightly alkaline pH and is little affected by increasing ionic strength. Reassembly is strongly inhibited by treatment with reducing agents such as dithiothreitol. The role of this protein in the formation of the fertilization membrane and its possible relation to the calcium-insoluble proteins of the mitotic apparatus are discussed.

Field-based nutritional response evaluation of the intolerant white lupin (Lupinus albus) cultivar Lucyanne to a lime-amended soil

2004 ◽  
Vol 142 (2) ◽  
pp. 153-161 ◽  
Author(s):  
S. J. KERLEY ◽  
I. F. SHIELD ◽  
T. SCOTT ◽  
H. STEVENSON
Keyword(s):  
Soil Ph ◽  
Dry Matter ◽  
Field Experiments ◽  
Lupinus Albus ◽  
Dry Matter Production ◽  
White Lupin ◽  
Alkaline Ph ◽  
Neutral Ph ◽  
Matter Production ◽  
Amended Soil

Two field experiments examined the nutritional responses of the white lupin (Lupinus albus L.) agronomic cultivar Lucyanne to lime-amended soil. In the first, plots and boundaries of a pre-existing lime-rate experiment were sampled in 1993. The maximum shoot dry matter production occurred between soil pH 4·9 and 7·2. Whole-shoot Al concentrations increased below soil pH 4·9, and plants died at pH 4·4. Although dry matter production declined in soil above pH 7·2, no chlorosis or plant death was seen. Only the whole-shoot soluble Ca concentration changed from neutral to alkaline pH soil: it was greatest when grown in the alkaline-pH soil. In the second experiment, plants were grown in neutral pH or limed soil in 2000. Shoots were divided into specific tissue types and analysed for Fe III and Fe II, as well as soluble and insoluble Ca fractions. When sampled in April after over-wintering, the higher Ca concentration in the limed compared with neutral-pH soil-grown plants was due mainly to insoluble Ca. No plants were chlorotic and no differences between the treatments in the concentrations of either form of Fe were found. In June no plants were chlorotic, however the concentrations of both total and soluble Ca fractions were greater in the limed than the neutral-pH soil-grown plants, and there was more stem Fe III and less leaf Fe II in these plants. The present study shows that the cultivar Lucyanne is not a reliable crop plant above pH 7·2, and the loss of shoot dry matter can be attributed to nutritional responses at a sub-chlorotic level of stress.

Modification of the poliovirus capsid by ultraviolet light

1981 ◽  
Vol 27 (11) ◽  
pp. 1185-1193 ◽  
Author(s):  
John De Sena ◽  
Donald L. Jarvis
Keyword(s):  
Ultraviolet Light ◽  
Uv Irradiation ◽  
Hela Cells ◽  
Reduced Glutathione ◽  
Type I ◽  
Alkaline Ph ◽  
Neutral Ph ◽  
Acid Ph ◽  
Ionic Compounds ◽  
Reducing Substances

Ultraviolet (UV) irradiation of type I poliovirus resulted in a modified (M) particle that had lost infectivity, lacked ability to adsorb to HeLa cells, lacked VP4, and was reduced in S value. Additional irradiation resulted in the loss of VP2, further reduction in S value, and permeability of the capsid to RNAse, This particle (C) as well as M contain the genome. Acid pH (5.5–6.5) and sulfhydryl-reducing substances (dithiothreitol, reduced glutathione, and L-cysteine) inhibited UV-induced modification of the capsid. UV irradiation at alkaline pH (7.5–8.5) resulted in more extensive modification of the capsid than irradiation at neutral pH. Ionic compounds were found to inhibit the modifying reaction.

pH, Hardness, and Humic Acid Influence Aluminum Toxicity to Rainbow Trout (Oncorhynchus mykiss) in Weakly Alkaline Waters

1994 ◽  
Vol 51 (6) ◽  
pp. 1345-1355 ◽  
Author(s):  
Deke T. Gundersen ◽  
Sjahrul Bustaman ◽  
Wayne K. Seim ◽  
Lawrence R. Curtis
Keyword(s):  
Rainbow Trout ◽  
Humic Acid ◽  
Oncorhynchus Mykiss ◽  
Growth Rates ◽  
Aluminum Toxicity ◽  
Alkaline Ph ◽  
Weakly Alkaline ◽  
Neutral Ph ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Specific Growth Rates

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed for either 96 h (acute) or 16 d (subacute) to various combinations of aluminum and hardness concentrations or aluminum and humic acid concentrations between pH 7.14 and 8.58. Aluminum-induced mortality was higher at weakly alkaline pH (7.95–8.58) (attributed to up to 10-fold higher filterable aluminum concentrations) than near-neutral pH (7.14–7.64). Growth rates were higher in 16-d hardness tests at weakly alkaline pH (0.188–1.600% of initial weight∙d−1) than for fish exposed to similar aluminum concentrations at near-neutral pH (−0.535–0.756%∙d−1). This suggested that polymeric and colloidal forms of aluminum were more potent than soluble forms in restricting growth. Hardness and humic acid appeared most protective to trout against subacute aluminum toxicity. Cumulative mortality of trout exposed to 1.50 mg aluminum∙L−1 at 103 or 20 mg∙L−1 hardness as CaCO3 was 10 and 45%, respectively. Hardness did not significantly protect against aluminum-induced growth inhibition. Trout exposed for 16 d to aluminum (0.53–2.56 mg∙L−1) and humic acid 4.31–5.23 mg∙L−1) had higher specific growth rates and decreased mortality than those exposed to aluminum and ho humic acid at any pH.

Electrophoretic Studies on Silicon Nitride: Traces of Silicates in UPW Shift Zeta Potential Similar to SC-1

2005 ◽  
Vol 103-104 ◽  
pp. 163-166 ◽  
Author(s):  
Alexander Pfeuffer ◽  
Wolfgang Bensch ◽  
Alfred Lechner ◽  
Harald Okorn-Schmidt
Keyword(s):  
Silicon Nitride ◽  
Zeta Potential ◽  
Pure Water ◽  
New Method ◽  
Alkaline Ph ◽  
Ultra Pure Water ◽  
Neutral Ph

In this paper we report on a new method of controlling the zeta potential of Si3N4 particles by addition of silicate traces to neutral ultra pure water (UPW). The positive zeta potential of Si3N4 at neutral pH shifts to negative values similar in alkaline pH solutions (e.g. with ammonia).

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