The article deals with the longitudinal waves in a nonlocal elastic rod. Regarding the nonlocal elasticity the Eringeen model has been assumed; the novelty is that this model is described in terms of ...the fractional Laplace operator. The standing waves are obtained by numerical solutions of the fractional differential equation in one-dimensional continuum. The obtained results are in accordance with the ones reported in the literature and highlight the dispersion phenomenon. The effects of the nonlocal contribution and of the fractional Laplacian order are also analyzed.
The use of indwelling medical devices is associated with a significant risk of infections by Staphylococcus aureus (S. aureus) which possesses a variety of virulence factors including many toxins and ...the ability to invade eukaryotic cells or to form biofilm on biotic and abiotic surfaces. The virulence factors above described are often related to proteins exposed on the bacterial surface. Blocking S. aureus colonization may reduce the incidence of invasive infectious diseases. Previously reports evaluated the anti-infective properties of serratiopeptidase (Spep), an extracellular metalloprotease produced by Serratia marcescens ATCC 21074 (E-15), in impairing virulence-related staphylococcal properties, such as attachment to inert surfaces and adhesion/invasion on eukaryotic cells. However, to date its mechanism of action is unknown.
Spep gene was PCR amplified and cloned into expression vector pET28b(+). The mutant EspepA was constructed from plasmid pET28b-Spep applying the one-step overlap extension PCR strategy. There sulting plasmids were costransformed in EcBL21(DE3) cells with the plasmid pRuW4inh1 harboring the Erwinia chrysanthemi secretion system. Bacterial pellets and supernatants were collected and analyzed by SDS-PAGE and zymography. The unambiguous identification and a detailed structure characterization of both the wild type and the mutant Spep were obtained by mass spectrometric analyses. The resultant supernatants sterilized by filtration were separately used to condition biofilm formation of S. aureus. Quantification was based on crystal violet method.
In this work we constructed Spep mutant by substituting the glutamic acid in the catalytic site with a residue of alanine. In this manner we were able to evaluate the anti-biofilm activity of Spep mutant in absence of proteolytic activity. As expected, this mutant did not display protease activity but it retained its anti-biofilm properties, suggesting that this action is independent by enzymatic activity.
New knowledge obtained from data reported in this paper calls attention to a novel mechanism of action of Spep. This protein could be developed as a potential "antipathogenic agent" capable to impair the ability of S. aureus to form biofilm on prostheses, catheters and medical devices, exploiting a mechanism different from the proteolytic activity.
The use of hydroxychloroquine (HCQ) in Primary Sjögren’s Syndrome (pSS) has been assessed in different studies over the last years, with conflicting results regarding its efficacy in sicca syndrome ...and extraglandular manifestations (EGM). The goal of this study was to compare the incidence rate of EGM in pSS patients with and without HCQ therapy.
We performed a multicenter retrospective study, including patients with pSS (European classification criteria) with at least 1 year of follow-up. Subjects with concomitant fibromyalgia, autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis were excluded. Demographics and pSS characteristics were recorded. The EGM were defined by EULAR-SS disease activity index (ESSDAI). Patients were divided into two groups according to their use or not of HCQ therapy. We evaluated the use of HCQ and its relationship to EGM. HCQ therapy was defined as the continuous use of the drug for at least 3 months. A descriptive analysis of demographics and pSS characteristics was performed. We compared the incidence of EGM between groups defined by HCQ therapy using chi
2
test or Fisher’s exact test. A total of 221 patients were included (97.3% women), mean age, 55.7 years (SD 14). Mean age at diagnosis, 48.8 years (SD 15); median disease duration, 60 months (IQR 35–84). One hundred and seventy patients (77%) received HCQ. About half of the patients had at least one EGM during the course of the disease, 20% of them developed an EGM before the onset of the sicca syndrome and 26% simultaneously with dryness symptom. Overall, EGM were less frequent in those on HCQ therapy (36.5% vs 63.5%,
p
< 0.001). Considering each EGM individually, the following manifestations were more frequent in the non-treated group: arthritis (
p
< 0.001), fatigue (
p
< 0.001), purpura (
p =
0.01), Raynaud phenomenon (
p
= 0.003), and hypergammaglobulinemia (
p
= 0.006). Immunosuppressive treatment was indicated on 28 patients (12.7%), 13 of which were receiving also HCQ. The first reason for those treatments was the presence of arthritis in 12/28 patients (42.8%), and the drug used in all the cases was methotrexate. Only three patients required immunosuppressive therapy with cyclophosphamide, due to the presence of glomerulonephritis, vasculitis, and interstitial lung disease. None of the patients received biologic therapy. The lower incidence of EGM was observed in patients on HCQ therapy supports its efficacy in pSS. However, further large scale prospective studies are needed to confirm these findings.
Aims
The purpose of this study was to evaluate the antimicrobial efficacy of five different proteases belonging to two different families on Staphylococcus aureus and Staphylococcus epidermidis ...strains.
Methods and Results
We used three serine proteases and two metalloproteases in single species biofilm formation assays and in human cell invasion processes. Following each protease incubation with bacterial cells, surface protein patterns were analysed by SDS‐PAGE and zymography. Some differently expressed proteins were identified by mass spectrometry.
Conclusions
The effect of tested proteases on biofilm formation was not related to the protease category but was strain‐dependent and was related to the biofilm formation capacity of each staphylococcal strain. Some proteases showed a nonspecific and indiscriminate effect on surface proteins, while others induced a discrete and reproducible action on protein profiles.
Significance and Impact of the Study
The inhibition of the surface‐related virulence factors is a promising avenue to overcome persistent infections caused by bacterial biofilms. To this end, we show here that proteases, in particular the metalloprotease serratiopeptidase, can interfere with adhesion and invasion of eukaryotic cells and biofilm formation in staphylococci and their use could represent a viable treatment for the development of novel combination therapies.
The physiological changes induced by indoleacetic acid (IAA) treatment were investigated in the totally sequenced Escherichia coli K-12 MG1655. DNA macroarrays were used to measure the mRNA levels ...for all the 4290 E. coli protein-coding genes; 50 genes (1.1 %) exhibited significantly different expression profiles. In particular, genes involved in the tricarboxylic acid cycle, the glyoxylate shunt and amino acid biosynthesis (leucine, isoleucine, valine and proline) were up-regulated, whereas the fermentative adhE gene was down-regulated. To confirm the indications obtained from the macroarray analysis the activity of 34 enzymes involved in central metabolism was measured; this showed an activation of the tricarboxylic acid cycle and the glyoxylate shunt. The malic enzyme, involved in the production of pyruvate, and pyruvate dehydrogenase, required for the channelling of pyruvate into acetyl-CoA, were also induced in IAA-treated cells. Moreover, it was shown that the enhanced production of acetyl-CoA and the decrease of NADH/NAD+ ratio are connected with the molecular process of the IAA response. The results demonstrate that IAA treatment is a stimulus capable of inducing changes in gene expression, enzyme activity and metabolite level involved in central metabolic pathways in E. coli.
Background Digital ulcers (DU) affect hand function in patients with systemic sclerosis (SSc) causing pain and transient or permanent disability. In clinical practice, it is not clear which are the ...best and more sensitive questionnaires and tools to evaluate hand involvement in SSc DU patients. In the last two years 86 patients with SSc were evaluated, 46 of them had digital ulcers (DU).All our patients with DU had severe functional impairment of daily living activities, disability and poor life quality but this was not reflected in our medical records. Objectives to evaluate the impact of DU in SSc patients by scoring: global disability by HAQ, pain by VAS, hand disability by the Cochin Hand Function Scale (CHFS) and functional mobility of the hand by modified Kapandji index (MKI). Methods A transversal cohort study. 86 medical records of SSc patients were analyzed, 46 of them with DU and hand impairment. Because scoring this impairment was not routine in our practice, we evaluated only 14 of the 46 SSc DU patients. Hand function and disability were evaluated through VAS, HAQ, CHFS and MKI. VAS reflects pain in a scale from 0 to 100. HAQ evaluates global disability in musculoskeletal disorders: HAQ >1.25 is related to severe and active disease. CHFS questionnaire consists of 18 questions (scored each from 0 to 5; total score 90) aiming to assess daily hands activities. MKI index evaluates wrist, opposition of the thumb and flexo-extension of the rest of the fingers (score 0 – 100 for both hands). Results 14 patients were evaluated;13 female; mean age of 55±10.16 years; mean evolution time of SSc 7±6.5 years. Diffuse SSc (dSSC) was diagnosed in 5 (36%) patients and limited (lSSc) in 9 (64%). In the 14 patients we analyzed three different status of DU: healed, active and with digital tissue loss. Seven patients (50%) had a combination of DU lesions. DU statusPatients: 14VASHAQCHFSMKI Healed85,25±2,741,413179 Active64±2,731,51884 Digit tissue loss74±2,731,792983 Mean valuein the 14 patients4,761,452581 For the 14 patients, irrespectively of the DU status, the mean value of HAQ was 1.45; VAS of 4,76, Cochin score with a mean value of 25 and the total mean value of Kapandji index was 81. These data reflects that impairment of the hand function (HAQ, CHFS and MKI) had a greater impact than pain (VAS) in our patients. Conclusions We found no difference between DU different status: pain and disability in daily activities were present in all three groups. Impairment had more impact in hand function than in pain scores. HAQ, CHFS, VAS and MKI as part of our clinical practice in SSc patients are useful tools to decide pharmacologic and non- pharmacologic treatment options. References Influences of clinical features of systemic sclerosis on the Michigan Hand Questionnaire (MHQ) Impens AJ et al Arthritis 2006; 54: S 483. Digital ulcers and outcomes assessment in sclerodema. Matucci-Cerinic M et al Rheumatology 2008; 47: 46-47. Using a self-reported functional store to asses disease progresiόn in systemic slerosis. Serednicka K et al Rheumatology 2007; 46: 1107-10 Assessing disability and Quality of life in Systemic sclerosis: construct validities of the Cochin Hand function scale, Health Assessment Questionnaire, Systemic sclerosis HAQ and Medical outcomes Study 36-Item Short Form Health Survey. Rannou F et al Arthritis 2007, 57: 94-102. Disclosure of Interest None Declared
Plants lack the adaptive immunity mechanisms of jawed vertebrates, so they rely on innate immune responses to defense themselves from pathogens. The plant immune system perceives the presence of ...pathogens by recognition of molecules known as pathogen-associated molecular patterns (PAMPs). PAMPs have several common characteristics, including highly conserved structures, essential for the microorganism but absent in host organisms. Plants can specifically recognize PAMPs using a large set of receptors and can respond with appropriate defenses by activating a multicomponent and multilayered response.
Lipopolysaccharides (LPSs) and lipooligosaccharides (LOSs) are major components of the cell surface of Gram-negative bacteria with diverse roles in bacterial pathogenesis of animals and plants that include elicitation of host defenses. Little is known on the mechanisms of perception of these molecules by plants and the associated signal transduction pathways that trigger plant immunity.
Here we addressed the question whether the defense signaling pathway in Arabidopsis thaliana was triggered by LOS from Xanthomonas campestris pv. campestris (Xcc), using proteomic and transcriptomic approaches. By using affinity capture strategies with immobilized LOS and LC-MS/MS analyses, we identified 8 putative LOS protein ligands. Further investigation of these interactors led to the definition that LOS challenge is able to activate a signal transduction pathway that uses nodal regulators in common with salicylic acid-mediated pathway. Moreover, we proved evidence that Xcc LOS are responsible for oxidative burst in Arabidopsis either in infiltrated or systemic leaves. In addition, gene expression studies highlighted the presence of gene network involved in reactive oxygen species transduction pathway.
•Lipooligosaccharide (LOS) from Xanthomonas campestris triggers plant immunity.•Lipooligosaccharide (LOS) from X. campestris triggers oxidative burst.•Eight putative LOS protein ligands have been identified by LC-MS/MS.•Gene expression studies highlighted putative signal transduction pathways.•Detection of ROS in Arabidopsis leaves infiltrated with LOS.
Indole-3-acetic acid (IAA) is a ubiquitous molecule playing regulatory roles in many living organisms. To elucidate the physiological changes induced by IAA treatment, we used Escherichia coli K-12 ...as a model system. By microarray analysis we found that 16 genes showed an altered expression level in IAA-treated cells. One-third of these genes encode cell envelope components, or proteins involved in bacterial adaptation to unfavourable environmental conditions. We thus investigated the effect of IAA treatment on some of the structural components of the envelope that may be involved in cellular response to stresses. This showed that IAA-treated cells had increased the production of trehalose, lipopolysaccharide (LPS), exopolysaccharide (EPS) and biofilm. We demonstrated further that IAA triggers an increased tolerance to several stress conditions (heat and cold shock, UV-irradiation, osmotic and acid shock and oxidative stress) and different toxic compounds (antibiotics, detergents and dyes) and this correlates with higher levels of the heat shock protein DnaK. We suggest that IAA triggers an increased level of alert and protection against external adverse conditions by coordinately enhancing different cellular defence systems.
This article concerns the blow up at infinity of global solutions of strongly damped polyharmonic Kirchhoff systems, involving lower order terms, a time dependent nonlinear dissipative function Q and ...a driving force f, under homogeneous Dirichlet boundary conditions. Some applications are presented in special subcases of f and Q.
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