Separate and overlapping specificities in rheumatoid arthritis antibodies binding to citrulline- and homocitrulline-containing peptides related to type I and II collagen telopeptides

IntroductionOur objective was to find out if there are antibodies binding to homocitrulline-containing type I and II collagen carboxyterminal telopeptides in sera of patients with rheumatoid arthritis (RA), and if these antibodies cross-react with citrulline and homocitrulline in the same peptide sequence.MethodsA total of 72 RA and 72 control sera were analyzed for binding using enzyme-linked immunosorbent assay to citrulline- or homocitrulline-containing type I and II collagen carboxyterminal telopeptides, as well as to cyclic citrullinated peptide (CCP) and to mutated citrullinated vimentin (MCV). Specificities of the antibodies were tested using inhibition-ELISA.ResultsOf the RA sera, 39 (54%) and 41 (57%) were positive for binding to CCP and MCV, respectively. Further, 34 (47%) and 30 (42%) of the patients had specific antibodies binding to and being inhibited by citrulline-containing type I collagen telopeptides and by citrulline-containing type II collagen carboxyterminal telopeptides, respectively. The corresponding figures regarding homocitrulline-containing type I and homocitrulline-containing type II collagen telopeptides were 16 (22%) and 14 (19%). Most of the patients, who were seropositive for citrullinated peptides, showed binding in multiple assays. A total of 10 (14%) RA patients were positive for all the tested peptide pairs, while 28 (39%) of them had antibodies that contained overlapping specifities between citrulline and homocitrulline in the same peptide sequence.ConclusionsAntibodies to both citrulline and homocitrulline containing type I and II collagen telopeptides can be found in sera of RA patients. These antibodies are not constant from one RA patient to another, but contain separate or overlapping specificities within the same peptide sequence varying between individuals. Our results suggest some relationship between citrulline and homocitrulline-recognizing antibodies, since homocitrulline antibodies exist mainly in individuals seropositive to anti-CCP and anti-MCV.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0515-z) contains supplementary material, which is available to authorized users.     

Synthesis of 2,3-diaryl-1,3-thiazolidine-4-one derivatives as selective cyclooxygenase (COX-2) inhibitors

A group of 2,3-diaryl-1,3-thiazolidine-4-ones, possessing a methylsulfonyl pharmacophore, were synthesized and their biological activities were evaluated for cyclooxygenase-2 (COX-2) inhibitory activity.     

Impaired fertility and spermiogenetic disorders with loss of cell adhesion in male mice expressing an interfering Rap1 mutant

The guanosine trisphosphatase Rap1 serves as a critical player in signal transduction, somatic cell proliferation and differentiation, and cell-cell adhesion by acting through distinct mechanisms. During mouse spermiogenesis, Rap1 is activated and forms a signaling complex with its effector, the serine-threonine kinase B-Raf. To investigate the functional role of Rap1 in male germ cell differentiation, we generated transgenic mice expressing an inactive Rap1 mutant selectively in differentiating spermatids. This expression resulted in a derailment of spermiogenesis due to an anomalous release of immature round spermatids from the seminiferous epithelium within the tubule lumen and in low sperm counts. These spermiogenetic disorders correlated with impaired fertility, with the transgenic males being severely subfertile. Because mutant testis exhibited perturbations in ectoplasmic specializations (ESs), a Sertoli-germ cell-specific adherens junction, we searched for expression of vascular endothelial cadherin (VE-cadherin), an adhesion molecule regulated by Rap1, in spermatogenic cells of wild-type and mutant mice. We found that germ cells express VE-cadherin with a timing strictly related to apical ES formation and function; immature, VE-cadherin-positive spermatids were, however, prematurely released in the transgenic testis. In conclusion, interfering with Rap1 function during spermiogenesis leads to reduced fertility by impairment of germ-Sertoli cell contacts; our transgenic mouse provides an in vivo model to study the regulation of ES dynamics.     

Metaproteomic analysis of a bacterial community response to cadmium exposure

Microbial communities are of great environmental, medical, and industrial significance. To date, biomolecular methods to study communities have focused on identifying species, with limited capabilities to reveal functions. Proteomics has the potential to yield functional information about these communities, but the application of proteomic methods to complex mixtures of unsequenced organisms is in its infancy. In this study, 2DE, MALDI-TOF/TOF MS, and de novo peptide sequencing were used for the separation and identification of proteins differentially expressed over time following exposure of a bacterial community to an inhibitory level of cadmium. Significant community proteome responses after 0.25, 1, 2, and 3 h of exposure to cadmium were observed, with more than 100 protein expression changes detected at each time point. Several temporal responses were observed, and the most common expression pattern was immediate up- or down-regulation within 15 min of shock followed by maintenance of that level. More than 100 unique differentially expressed proteins were identified through database searching and de novo sequencing. Proteins of importance in the cadmium shock included ATPases, oxidoreductases, and transport proteins. The ability of proteomics to detect the differential regulation of these proteins even during short cadmium exposures shows that it is a powerful tool in explaining cellular mechanisms for a mixed culture. This is the first report of the large-scale identification of proteins involved in the dynamic response of a community of unsequenced bacteria using de novo sequencing.     

Chemical investigation of different extracts and essential oil from the tubers of (Tunisian)Cyperus rotundus. Correlation with their antiradical and antimutagenic properties

The mutagenic potential of aqueous, Total Oligomers Flavonoids (TOF), ethyl acetate, and methanol extracts as well as essential oil (EO) obtained from tubers ofCyperus rotundus L. was assessed by “Ames assay”, usingSalmonella tester strains TA98 and TA100, and “SOS chromotest” usingEscherichia coli PQ37 strain with and without an exogenous metabolic activation system (S9). None of the different extracts showed a mutagenic effect. Likewise, the antimutagenicity of the same extracts was tested using the “Ames test” and the “SOS chromotest”. Our results showed thatC. rotundus extracts have antimutagenic effects withSalmonella typhimurium TA98 and TA100 strains towards the mutagen Aflatoxin B1 (AFB1), as well as withE. coli PQ37 strain against AFB1 and nifuroxazide mutagens. A free radical scavenging test was used in order to explore the antioxidant capacity of the extracts obtained from the tubers ofC. rotundus. TOF, ethyl acetate and methanol extracts showed an important free radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. These extracts showed IC50 values of respectively 5, 20 and 65 μg/ml. The beneficial effects of TOF, ethyl acetate, methanol and essential oil extracts ofC. rotundus have been assessed by antioxidant and antimutagenic activities.     

8-plex quantitation of changes in cerebrospinal fluid protein expression in subjects undergoing intravenous immunoglobulin treatment for Alzheimer's disease

An 8-plex version of an isobaric reagent for the quantitation of proteins using shotgun methods is presented. The 8-plex version of the reagent relies on amine-labeling chemistry of peptides similar to 4-plex reagents. MS/MS reporter ions at 113, 114, 115, 116, 117, 118, 119, and 121 m/z are used to quantify protein expression. This technology which was first applied to a test mixture consisting of eight proteins and resulted in accurate quantitation, has the potential to increase throughput of analysis for quantitative shotgun proteomics experiments when compared to 2- and 4-plex methods. The technology was subsequently applied to a longitudinal study of cerebrospinal fluid (CSF) proteins from subjects undergoing intravenous Ig treatment for Alzheimer's disease. Results from this study identify a number of protein expression changes that occur in CSF after 3 and 6 months of treatment compared to a baseline and compared to a drug washout period. A visualization tool was developed for this dataset and is presented. The tool can aid in the identification of key peptides and measurements. One conclusion aided by the visualization tool is that there are differences in considering peptide-based observations versus protein-based observations from quantitative shotgun proteomics studies.     

Morphological Changes Induced By Extremely Low‐Frequency Electric Fields

In this paper, morphological effects of electric fields on avian erythrocytes (nucleated red blood cells) have been studied in detail. Morphological changes include rounding and cytoplasm transparency. It has been shown that the effect is non‐thermal. Careful imaging and image analyses have been carried out to show that the degree of this effect is frequency‐dependent, and has a higher conversion rate at higher temperatures. Furthermore, to better understand the mechanisms behind the morphological changes, we investigated the dedifferentiation hypothesis and performed a series of tests on avian erythrocytes including fluorescence spectroscopy for hemoglobin, and tests on human umbilical cord blood, mesenchymal stem cells, and bone marrow mesenchymal stem cells including flow‐cytometry analysis for expression of certain markers and calcium staining. Bioelectromagnetics. 2019;40:375–390. © 2019 Bioelectromagnetics Society.     

Association of single nucleotide autophagy-related protein 5 gene polymorphism rs2245214 with susceptibility to non–small cell lung cancer

Introduction : Autophagy is a mechanism that is involved in the regulation of cellular life, apoptosis, and stemness while its intervening genes play important functions in various cancers including lung cancer. ATG5 is one of the key genes for the regulation of the autophagy pathway. In this study, our team has investigated the potential relationship between ATG5 gene polymorphism rs2245214 with non–small cell lung cancer (NSCLC) in a subpopulation of patients from southern Iran. In this study, 34 patients with NSCLC (20 males and 14 females [mean age: 12.86 ± 60.47 years]) and 50 healthy subjects (30 males and 20 females [mean age: 13.09 ± 56.62 years]) were studied in terms of the genotype of the ATG5 gene. We used restriction fragment length polymorphism and analyzed the results using SPSS software (v.23). The results revealed that subjects harboring the guanine/cytosine (GC) genotype of the rs2245214 ATG5 gene polymorphism had suffered less from NSCLC, whereas the prevalence of the C-allele of this polymorphism was significantly higher in patients with NSCLC ( P < 0.05). On the basis of the results of logistic regression, the presence of this C-allele may predict the risk of lung cancer ( P value = 0.011; OR, 3.52; 95% CI, 1.33-9.26). This study concludes that the C-allele of the rs2245214 ATG5 gene polymorphism is associated with increased susceptibility to NSCLC, whereas the GC genotype of this polymorphism is associated with decreased risk and might therefore have a protective role in the development of NSCLC.     

Exotoxin A-PLGA nanoconjugate vaccine against Pseudomonas aeruginosa infection: protectivity in murine model

Recombinase polymerase amplification (RPA) is an isothermal amplification technique. Because of its short detection cycle and high specificity, it has been applied in various fields. However, the design of probe on the efficiency of RPA is not well understood and the effect of sequence mismatches of oligonucleotides on the performance of RPA is rarely discussed. In this study, we found that different primers with the same probe have a slight effect on the efficiency of fluorescent RPA, and different probes with the same amplified region have a great influence on the efficiency of fluorescent RPA. We summarized the design rules of probes suitable for fluorescent RPA by analyzing the experimental data. The rule is that the best distance between fluorescent groups in the probe is 1–2 bases, and the G content should be reduced as far as possible. In addition, we verified this rule by designing a series of probes. Furthermore, we found the base mismatches of the probe had a significant effect on RPA, which can lead to false positives and can change the amplification efficiency. However, 1–3 mismatches covering the center of the primer sequence only affect the amplification efficiency of RPA, not its specificity. And with an increase in the number of primer mismatches, the efficiency of RPA will decrease accordingly. This study suggests that the efficiency of fluorescent RPA is closely related to the probe. We recommend that when designing a fluorescent probe, one must consider the presence of closely related non-targets and specific bases.

     

Roadmap to net-zero carbon emissions in commercial microalgae-based products: environmental sustainability and carbon offset costs

Journal of Applied Phycology - The global ecological awakening has made carbon–neutral production an imperative. Ignoring the call of the mermaid to protect the environment does not seem to...