China
Africa
Explore chapters and articles related to this topic
Global Regulation of Preservatives and Cosmetic Preservatives
Published in Philip A. Geis, Cosmetic Microbiology, 2020
The CIR process determined that chloroacetamide is unsafe for use in cosmetics. The following preservatives presented problems and as of this writing have insufficient data status: Benzylparaben (2019)Sodium iodate (1995—no reported uses)Glutaral2-Bromo-2-nitropropane-1,3-diol and 5-bromo-5-nitro-1,3 dioxane when used where amines and nitrosamines could be formedFormaldehyde in aerosols
Global regulation of preservatives and cosmetic preservatives
Published in Philip A. Geis, Cosmetic Microbiology, 2006
The CIR process determined that chloroacetamide is unsafe for use in cosmetics. The following preservatives presented problems and as of this writing have insufficient data status: BenzylparabenSodium iodateGlutural2-Bromo-2-nitropropane-1,3-diol and 5-bromo-5-nitro-1,3 dioxane when used where amines and nitrosamines could be formedFormaldehyde in aerosols
The Modification of Cysteine
Published in Roger L. Lundblad, Chemical Reagents for Protein Modification, 2020
Haloacetates, the corresponding amides and derivatives have been extremely useful reagents for the specific modification of cysteinyl residues. These reagents react with cysteine via a SN2 reaction mechanism to give the corresponding carboxymethyl or carboxamidomethyl derivatives (see Figure 5). When a rapid reaction is desired, the iodine-containing compounds are used. For example, the reaction of iodoacetate with cysteine is approximately twice as fast as the reaction of bromoacetate and 20 to 100 times as rapid as chloroacetate. There are situations in which fast reaction rates are not necessarily desirable, such as the studies of Gerwin on streptococcal proteinase.9 This particular study was of considerable importance since it emphasized the importance of microenvironmental effects on the reaction of cysteine with α-halo acids and α-halo amides. Chloroacetic acid was far less effective than chloroacetamide. The sulfhydryl group at the active site of streptococcal proteinase has enhanced reactivity in that modification with iodoacetate readily occurred in the presence of 100- to 1000-fold excess of β-mercaptoethanol or cysteine. The enhanced reactivity of the active-site cysteine is also apparent from a comparison of the relative rates of modification of streptococcal proteinase and reduced glutathione. The rate of modification of streptococcal proteinase is 50 to 100 times more rapid than that of glutathione. The unique properties of this cysteine residue can be explained in part by the presence of an adjacent histidyl residue which was demonstrated by an elegant series of studies by Liu.10 Although histidine residues will react with α-halo acids and amides, the presence of an adjacent cysteine residue precluded the use of this class of reagents to demonstrate the presence of a histidyl residue at the active site of streptococcal proteinase. Liu took advantage of the reversible modification of cysteinyl residues with sodium tetrathionite to modify the active-site histidine.
Targeting citrullination in autoimmunity: insights learned from preclinical mouse models
Published in Expert Opinion on Therapeutic Targets, 2021
Ylke Bruggeman, Fernanda M.C. Sodré, Mijke Buitinga, Chantal Mathieu, Lut Overbergh, Maria J.L. Kracht
Different preclinical mouse models of MS exist, reflecting the disease heterogeneity. This includes a spontaneous demyelination model (ND4), a cuprizone-induced model (CPZ) and an immune-mediated model that is characterized by immune cell infiltration in the CNS after immunization (experimental autoimmune encephalomyelitis (EAE)) [104]. The therapeutic potential of PAD inhibition has been evaluated in these different in vivo models of demyelination (Table 5). Inhibition of PADs using 2-chloroacetamide, a modest irreversible PAD inhibitor, was able to prevent disease development or suppress disease progression after onset and even reverse clinical disease phenotypes. Additional studies on EAE models showed potency for reversible PAD inhibitors, which might be preferred as therapeutics [105,106]. All PAD inhibitors on the autoimmune-dependent EAE models prevented infiltration of T lymphocytes in the CNS tissues and decreased proliferation of autoreactive T cells ex vivo after stimulation with both native and citrullinated immunogens. In contrast to these promising results with PAD inhibition, EAE induction in PAD2 knockout mice did not affect disease progression [107]. This could implicate a compensatory mechanism of PAD4. Furthermore, the different MS pathology models suggest a direct function of PAD inhibition in the myelin tissue in addition to immune modulatory effects.
Preparation and evaluation of polyphenol derivatives as potent antifouling agents: addition of a side chain affects the biological activity of polyphenols
Published in Biofouling, 2022
Xuan Wang, Xiaohui Jiang, Liangmin Yu
To investigate the effects of polyphenol derivatives on the growth of C. vulgaris and N. closterium more quickly and conveniently, the maximum algal absorption wavelengths and standard working curves of the algal absorbance and concentration were determined. The maximum absorption wavelengths of C. vulgaris and N. closterium were both 680 nm (Figure S11 in Supplementary information 3). There was a significant positive and linear correlation between the absorbance and the concentration of algae; their correlation coefficients were > 0.9880 (Figure 4a and b). The effect of polyphenol derivatives on C. vulgaris and N. closterium is shown in Figure 4c and Figure 4d, respectively. The polyphenol derivatives showed different levels of inhibitory effects compared with that of the control samples, and the inhibition effect was time-dependent. In particular, compounds a3, b1, b2, b3 and b4, whose inhibition rates were > 93% for C. vulgaris at 10 d, showed superior inhibitory effects. Their inhibition rates were > 57% for N. closterium at 10 d, and the anti-algal activity followed the descending order of b3, a3, b2, b1, and b4. In contrast, compounds a1, a2, and a4 exhibited relatively poor inhibition rates. Compared with other amide groups (such as acrylamide, acetamide, and benzamide), the anti-algal activities of the chloroacetamide groups of compounds a3 and b3 were higher for C. vulgaris and N. closterium. In addition, the inhibition rates of compounds b0, b1, b2, b3, and b4 against C. vulgaris and N. closterium were higher than those of compounds a0, a1, a2, a3, and a4, respectively.
Bacterial membrane vesicles and phages in blood after consumption of Lacticaseibacillus rhamnosus JB-1
Published in Gut Microbes, 2021
Kevin Champagne-Jorgensen, Tamina A. Jose, Andrew M. Stanisz, M. Firoz Mian, Alexander P. Hynes, John Bienenstock
Proteomics analyses were performed by the Center for Advanced Proteomics Analyses, a Node of the Canadian Genomic Innovation Network that is supported by the Canadian Government through Genome Canada. Briefly, samples in PBS (approx. 200 μg protein; 3 paired samples per group) were dried, reconstituted in 100 μL 50 mM ammonium bicarbonate with 10 mM TCEP-HCl, and vortexed for 1 h at 37°C. Chloroacetamide (55 mM) was added for alkylation and samples vortexed for 1 h at 37°C. Trypsin (1 μg) was then added and samples digested for 8 h at 37°C. Samples were dried and solubilized in 5% acetonitrile and 0.2% formic acid, then loaded on a 1.5 μL pre-column (Optimize Technologies, Oregon City, USA). Peptides were separated on a home-made reversed-phase column (150 μm inner diameter by 200 mm) with a 56 min gradient from 10% to 30% acetonitrile with 0.2% formic acid and a 600 nL/min flow rate on an Easy nLC-1000 connected to a Q Exactive HF Orbitrap LC-MS/MS System (Thermo Scientific, San Jose, USA). Each full MS spectrum, acquired at a resolution of 60,000, was followed by tandem-MS spectra acquisition on the 15 most abundant multiply charged precursor ions. Tandem-MS experiments were performed using higher energy collision dissociation at a collision energy of 27%. Data were processed using PEAKS X (Bioinformatics Solutions, Waterloo, Canada) and the UniProt mouse and L. rhamnosus GG (ATCC 53103) databases. Mass tolerances on precursor and fragment ions were 10 ppm and 0.01 Da, respectively. Fixed modification was carbamidomethyl. Variable selected posttranslational modifications were oxidation, deamidification, and phosphorylation. The data were visualized with Scaffold (v. 4.3.0; Proteome Software, Portland, USA), protein threshold 99%, with at least 2 peptides identified and a false-discovery rate of 1% for peptides). We used the average intensity of the 3 highest-intensity peptides for further analyses.