ICPMS analysis of proteins separated by Native-PAGE: Evaluation of metaloprotein profiles in human synovial fluid with acute and chronic arthritis

Holo/apo conversion two-dimensional urea PAGE for speciation of Fe3+-bound transferrin in serum

This paper presents holo/apo conversion two-dimensional urea polyacrylamide gel electrophoresis (HAC-2D urea PAGE) as a novel method for speciating Fe3+-bound transferrin (Tf) species in biological samples, with a combination of metal ion contaminant sweeping (MICS) technique and Fe3+ detection PAGE. In the HAC-2D urea MICS-PAGE approach, HAC was performed to dissociate all the Fe3+ ions bound to Tf from the Fe-Tf species, during a two-step urea PAGE. Using this method, Fe2-Tf, FeN-Tf, and FeC-Tf (holo-Tf, Fe3+-bound Tf attached to N-lobe, and Fe3+-bound Tf attached C-lobe, respectively) were completely isolated based on the difference in the higher-order structure of Tf, visible as horizontally aligned spots off the diagonal. The Fe3+ ions bound to Tf in each gel fraction were determined using PAGE with a fluorescent probe. Without the MICS technique, which electrophoretically removes all contaminant Fe3+ ions from the gel medium to ensure accurate determination of the Fe3+ concentration, it becomes challenging to precisely measure the distribution of metalloprotein species owing to the contaminants. Finally, the distribution of each Fe-bound Tf in a standard human serum sample was successfully determined by complete separation from large amounts of coexisting proteins, and the free Fe3+ concentration in the serum was estimated.

Copper Traces Quantification in Bee's Products by Solid Surface Fluorescence. A Green Analytical Proposal

A new methodology based on the fluorescence of Cu(II) ternary system with o-phenanthroline (o-Phen) and eosin (Eo) dyes is proposed. The metal was selectively retained on Nylon membranes and the solid surface fluorescence (SSF) was used for anayte quantification. Experimental variables that influence the formation of Cu(II)-o-Phen-eo system and retention step were studied and optimized. At optimal experimental conditions, an adequate tolerance to foreign species was shown with a LOD of 1.18 ng L-1 and a LOQ of 3.57 ng L-1. The methodology was evaluated for their greenness profile and successfully applied to analyte determination in bee's products of West-Center Argentina. Recovery studies showed values near to 100% being satisfactorily validated by ICP-MS.

Two-Dimensional Polyacrylamide Gel Electrophoresis for Metalloprotein Analysis Based on Differential Chemical Structure Recognition by CBB Dye

In an effort to develop an analytical method capable of finding new metalloproteins, this is the first report of a new diagonal gel electrophoresis method to isolate and identify metalloproteins, based on the molecular recognition of holo- and apo-metalloproteins (metalbound and -free forms, respectively) by CBB G-250 dye and employing metal ion contaminant sweeping-blue native-polyacrylamide gel electrophoresis (MICS-BN-PAGE). The difference in electrophoretic mobilities between holo- and apo-forms was exaggerated as a result of interactions between the metalloproteins and the dye with no metal ion dissociation. The different binding modes of proteins with CBB G-250 dye, primarily related to hydrogen bonding, were confirmed by capillary zone electrophoresis (CZE) and molecular docking simulations. Due to in-gel holo/apo conversion between the first and second dimensions of PAGE, holo-metalloproteins in the original sample were completely isolated as spots off the diagonal line in the second dimension of PAGE. To prove the high efficiency of this method for metalloprotein analysis, we successfully identified a copper-binding protein from a total bacterial soluble extract for the first time.

Serum Cesium, Rhenium, and Rubidium in Rheumatoid Arthritis Patients

A considerable attention has been focused on the possible association between ultra-trace elements (UTEs) status and pathogenesis of many diseases including rheumatoid arthritis (RA). UTEs have important roles in numerous metabolic processes. Serum Cs, Rb, and Re levels in RA are not studied previously. The correlation of serum Cs, Rb, and Re levels with the well-known serological parameters, anticyclic citrullinated protein antibody (ACPA), C-reactive protein (CRP), ESR, and rheumatoid factor (RF) is also not studied previously. The present study aimed to measure the level and the correlation between serum UTEs with various blood tests results in RA patients. Serum Cs, Rb, Re, ACPA, CRP, RF, and ESR were measured in Iraqi RA patients who have a positive ACPA (ACPA > 25 U/ml) and compared with healthy individuals. There were significant elevations (p < 0.05) in serum levels of all the measured parameters as compared with those of the healthy control group except Rb and uric acid which have not been changed. Subgrouping of patients according to the results of CRP and RF leads to different results. In the low-CRP group, the high-RF subgroup showed an elevation of ACPA, Cs, and ESR in comparison with the low-RF patients. In the high-CRP group, the patients with high RF showed an increase in the levels of Cs, Rb, ESR, and ACPA. The patient group with high RF and high CRP showed more significant correlations between serum UTEs and serological tests. Serum levels of UTEs were significantly altered in RA patients. The variations in the serum levels of the measured parameters in RA need more investigation to explore the possible association between these UTEs and RA. RA subgroups, according to the results of CRP and CPA, produce more and various information than taking RA as a whole group in the estimation of UTEs.

Endometriosis progression in tumor necrosis factor receptor p55-deficient mice: Impact on oxidative/nitrosative stress and metallomic profile

The present study was conducted to investigate whether the deficiency of tumor necrosis factor receptor p55 (TNFRp55) modulates oxidative/nitrosative stress and metallomic profile into the peritoneal cavity during the experimental endometriosis progression in mice. Female C57BL/6 mice, wild-type (WT) and TNFRp55 knockout (KO) of two months were used. Endometriosis was induced experimentally by autotransplanting three pieces of the right uterine horn to the intestinal mesentery. After four weeks, endometriotic-like lesions and peritoneal lavage fluid were collected. The obtained peritoneal fluid was analyzed for nitrite levels using the Griess method and trace elements concentrations by ICP-MS. Both endometriotic-like lesions and cells isolated from peritoneal lavage were analyzed for the following oxidative/nitrosative stress markers: inducible nitric oxide synthase (iNOS) expression by Western Blot; total antioxidant capacity (TAC), the activity of two antioxidant enzymes (CAT and GPX) and thiobarbituric acid-reactive substances (TBARS) concentration, by spectrophotometric method; and protein carbonyl content and nitrotyrosine presence by ELISA. In comparison to WT group, KO mice exhibited larger lesion volume; higher levels of nitrite, copper (Cu) and strontium (Sr) in the peritoneal fluid; increased TAC, CAT, and GPX in peritoneal lavage cells; decreased concentration of TBARS in lesions and protein carbonyl in peritoneal lavage cells. Significant positive correlations between Cu and lesion volume, Sr and lesion volume, and Cu and Sr were obtained. Our results suggest that the TNFRp55 deficiency increases antioxidant protection and promotes high Cu-Sr concentrations in the peritoneal cavity, which favors the progression of experimental endometriosis.