Real-time electrochemical detection of extracellular nitric oxide in tobacco cells exposed to cryptogein, an elicitor of defence responses

It was previously reported that cryptogein, an elicitor of defence responses, induces an intracellular production of nitric oxide (NO) in tobacco. Here, the possibility was explored that cryptogein might also trigger an increase of NO extracellular content through two distinct approaches, an indirect method using the NO probe 4,5-diaminofluorescein (DAF-2) and an electrochemical method involving a chemically modified microelectrode probing free NO in biological media. While the chemical nature of DAF-2-reactive compound(s) is still uncertain, the electrochemical modified microelectrodes provide real-time evidence that cryptogein induces an increase of extracellular NO. Direct measurement of free extracellular NO might offer important new insights into its role in plants challenged by biotic stresses.     

Arginine-induced pancreatic hormone secretion during exercise in rats

Trabelsi, Fethi, and Jean-Marc Lavoie. Arginine-inducedpancreatic hormone secretion during exercise in rats.J. Appl. Physiol. 81(6):2528-2533, 1996.The aim of the present investigation was to1) determine whetherarginine-induced pancreatic hormone secretion can be modified during anexercise bout, and 2) verify whetherthe sectioning of the hepatic branch of the vagus nerve can alter thearginine-induced insulin and glucagon secretion during exercise inrats. To this end, we studied the effects of an intraperitonealinjection of arginine (1 g/kg body mass) during an exercise bout (30 min, 26 m/min, 0% grade) on the pancreatic hormone responses. Theseeffects were determined in one group of sham-operated exercising ratsand compared with three control groups: one group of resting rats, onegroup of saline-injected exercising rats, and one group ofhepatic-vagotomized exercising rats. Five minutes after the injectionof arginine, significant (P < 0.05)increases in insulin, glucagon, and C-peptide concentrations wereobserved in exercising as well as in resting rats. These responses werenot, however, altered by the hepatic vagotomy and/or by theexercise bout. It is concluded that arginine is a potent stimulus ofpancreatic hormone secretion during exercise, even though thesympathoadrenal system is activated. These results also indicate that ahepatic vagotomy does not seem to influence arginine-inducedhormonal pancreatic responses and question the role of the putativehepatic arginoreceptors in the control of the pancreatic hormonesecretion during exercise.

     

An empirical study of web browsers’ resistance to traffic analysis and website fingerprinting attacks

Anonymity protocols are employed to establish encrypted tunnels to protect the privacy of Internet users from traffic analysis attacks. However, the attackers strive to infer some traffic patterns’ characteristics (e.g. packet directions, packet sizes, inter-packet timing, etc.) in order to expose the identities of Internet users and their activities. A recent and popular traffic analysis attack is called website fingerprinting which reveals the identity of websites visited by target users. Existing work in the literature studied the website fingerprinting attack using a single web browser, namely Firefox. In this paper we propose a unified traffic analysis attack model composed of a sequence of phases that demonstrate the efficiency of website fingerprinting attack using popular web browsers under Tor (The Onion Router). In addition, we reveal the main factors that affect the accuracy of website fingerprinting attack over Tor anonymous system and using different browsers. To the best of our knowledge, no previous study uncovered such factors by deploying real-world traffic analysis attack utilizing the top five web browsers. The outcomes of the research are very relevant to Internet users (individuals/companies/governments) since they allow to assess to which extent their privacy is preserved in presence of traffic analysis attacks, in particular, website fingerprinting over different browsers. A recommendation for future research direction regarding the investigation of website fingerprinting over different scenarios is also provided.     

Synthesis and antimicrobial activity of new 1,2,4-triazole and 1,3,4-thiadiazole derivatives

In this study, new 3-[(1(2H)-phthalazinone-2-yl(methyl/ethyl]-4-aryl-1,2,4-triazole-5-thione and 2-[[1(2H)-phthalazinone-2-yl]methyl/ethyl]-5-arylamino-1,3,4-thiadiazole derivatives were synthesized. Antimicrobial properties of the title compounds were investigated against two Gram (+) bacteria (S. aureus, B. subtilis), two Gram ( ? ) bacteria (P. aeruginosa, E. coli) and two yeast-like fungi (C. albicans and C. parapsilosis) using the broth microdilution method. Generally the compounds were found to be active against B. subtilis and the fungi. Derivatives carrying a 1,3,4-thiadiazole ring generally showed higher antimicrobial activity against B. subtilis and the fungi when compared to other synthesized compounds.     

Co-Circulation of Toscana Virus and Punique Virus in Northern Tunisia: A Microneutralisation-Based Seroprevalence Study

Background

In northern Tunisia, the co-circulation of two related sand fly-borne phleboviruses, Toscana virus (TOSV) and Punique virus (PUNV) was previously demonstrated. In contrast to TOSV, a prominent human pathogen, there is no data supporting that PUNV is capable to infect and cause disease to humans. We studied the respective involvement of TOSV and PUNV in human infections in northern Tunisia through a seroprevalence study.

Methods

The presence of TOSV and PUNV neutralising antibodies (NT-Ab) was tested in human sera collected from 5 districts of the governorate of Bizerte, and the titres of NT-Ab were estimated by microneutralisation (MN) assay.

Principal Findings

A total of 1,273 sera were processed. TOSV and PUNV NT-Ab were detected in 522 (41%) and 111 sera (8.72%) respectively. TOSV seroprevalence varied from 17.2% to 59.4% depending on the district. Analysis of TOSV geometric mean titre values demonstrated a constant increase according to the age. The vast majority of sera containing NT-Ab were found to be more reactive toward TOSV than PUNV. Indeed, past infections with PUNV and TOSV were undisputable for 5 and 414 sera, respectively.

Conclusions

PUNV may be capable to infect humans but at a low rate. TOSV is responsible for the vast majority of human infections by sand fly-borne phleboviruses in northern Tunisia. TOSV must be considered by physician and tested in diagnostic laboratories for patients with meningitis and unexplained fever in northern Tunisia.     

Inflammatory response in induced sputum mononuclear cells from patients with acute exacerbation of asthma

Examination of sputum provides a direct method to investigate airway inflammation non-invasively in particular Th1 (IL-2, IFN-gamma) and Th2 (IL-4, IL-10) cytokine production. IL-2, IL-4, IL-10 and IFN-gamma cytokine were studied in induced sputum mononuclear cells of asthmatic patients. Sputum induction was performed on 10 patients and 10 normal controls. Basal and mitogen-stimulated cytokine production was determined in induced sputum T-cell culture. Supernatants were collected and assayed not only with specific ELISA but also with polymerase chain reaction (PCR) techniques. Data showed a significantly higher production of IL-10 by both the ELISA and the RT-PCR techniques in asthmatic patients compared with sputum mononuclear cells from healthy controls. IL-4 production was detected at a low level using the ELISA method in asthmatic patients. The RT-PCR analysis detected a significantly IL-4-mRNA expression in all asthmatic patients, compared with controls. Results of IL-10 and IL-4 mRNA expression were reproducible. We did not find any alteration in the expression of the type 1 derived cytokines (IL-2 and IFN-gamma) in asthmatic patients or in healthy controls. Our study showed a tendency of induced sputum mononuclear cells to express a Th2-like cytokine pattern in acute exacerbation of asthmatic patients, where IL-10 and IL-4 are synthesized in larger amounts. The combination of sputum induction as a non-invasive tool to explore the lung and the identification of disease-associated cytokine expression and of specific cytokine mRNA should help elucidate mechanisms of the immunologically mediated inflammatory responses in asthma.     

MicroRNA-155 targets SMAD2 and modulates the response of macrophages to transforming growth factor-{beta}

Transforming growth factor-beta (TGF-β) is a pleiotropic cytokine with important effects on processes such as fibrosis, angiogenesis, and immunosupression. Using bioinformatics, we identified SMAD2, one of the mediators of TGF-β signaling, as a predicted target for a microRNA, microRNA-155 (miR-155). MicroRNAs are a class of small non-coding RNAs that have emerged as an important class of gene expression regulators. miR-155 has been found to be involved in the regulation of the immune response in myeloid cells. Here, we provide direct evidence of binding of miR-155 to a predicted binding site and the ability of miR-155 to repress SMAD2 protein expression. We employed a lentivirally transduced monocyte cell line (THP1-155) containing an inducible miR-155 transgene to show that endogenous levels of SMAD2 protein were decreased after sustained overexpression of miR-155. This decrease in SMAD2 led to a reduction in both TGF-β-induced SMAD-2 phosphorylation and SMAD-2-dependent activation of the expression of the CAGA(12)LUC reporter plasmid. Overexpression of miR-155 altered the cellular responses to TGF-β by changing the expression of a set of genes that is involved in inflammation, fibrosis, and angiogenesis. Our study provides firm evidence of a role for miR-155 in directly repressing SMAD2 expression, and our results demonstrate the relevance of one of the two predicted target sites in SMAD2 3'-UTR. Altogether, our data uncover an important role for miR-155 in modulating the cellular response to TGF-β with possible implications in several human diseases where homeostasis of TGF-β might be altered.