Search Results (23)

Vibrio parahaemolyticus is the leading cause of seafood-borne gastroenteritis. While its interaction with edible marine animals is well known, its impact on non-edible hosts remains under-explored. Using the sea anemone Exaiptasia pallida, we investigated Vibrio parahaemolyticus pathogenicity and the role of the Type III Secretion System (T3SS). In vivo infections with a 10⁷ CFU/mL inoculum of V. parahaemolyticus induced a 50% mortality rate after 7 days (LC50). Using isogenic mutant strains of V. parahaemolyticus with impaired key regulatory components of T3SS, impT3SS1 (CAB2), and impT3SS2 (CAB3), we demonstrated that disruption of T3SS1 significantly reduced anemone mortality. Next, we observed a time-dependent downregulation of T3SS1 effectors (VPA0450, VopQ, VopS) after 3 h and 6 h in the presence of the sea anemone, contrasting with the T3SS2-dependent VopC increased expression after 6 h. Further results support the capacity of V. parahaemolyticus to sense host-derived chemical cues and adjust its virulence strategies accordingly. Collectively, our findings broaden the understanding of V. parahaemolyticus O3:K6 as a pathogen for cnidarians and provide evidence of a major role for the T3SS1 effectors in this emerging model of host–pathogen interactions. Full article

Vibrio alginolyticus is a Gram-negative pathogen of both marine animals and humans, resulting in significant losses for the aquaculture industry. Emerging evidence indicates that V. alginolyticus manipulates cell death for its pathogenicity, but the underlying molecular mechanisms remain unclear. Here, a gene designated vopS in V. alginolyticus HY9901 was identified, which was predicted to encode the T3SS effector protein. To determine whether VopS contributes to the pathogenesis of V. alginolyticus, the ΔvopS mutant strain was constructed and phenotypically characterized. The deletion of VopS not only reduced the ability to secrete extracellular proteases and virulence but also affected the expression of the T3SS genes. Furthermore, VopS was cytotoxic and induced apoptosis, as confirmed by elevated LDH and the activation of caspase-3. Metabolomic analysis revealed considerable metabolomic disruptions upon V. alginolyticus infection. The VopS effector induced host cell ferroptosis by promoting the synthesis of adrenic acid, depleting cellular glutathione, and subsequently increasing the accumulation of ferrous (Fe²⁺). Taken together, our findings provide that the VopS effector is an essential virulence factor of V. alginolyticus, which can lead to ferroptosis. Full article

Competition between bacterial species is a major factor shaping microbial communities. It is possible but remains largely unexplored that competition between bacterial pathogens can be mediated through antagonistic effects of bacterial effector proteins on host systems, particularly the actin cytoskeleton. Using Salmonella Typhimurium invasion into cells as a model, we demonstrate that invasion is inhibited if the host actin cytoskeleton is disturbed by actin-specific toxins, namely, Vibrio cholerae MARTX actin crosslinking (ACD) and Rho GTPase inactivation (RID) domains, Photorhabdus luminescens TccC3, and Salmonella’s own SpvB. We noticed that ACD, being an effective inhibitor of tandem G-actin-binding assembly factors, is likely to inhibit the activity of another Vibrio effector, VopF. In reconstituted actin polymerization assays and by live-cell microscopy, we confirmed that ACD potently halted the actin nucleation and pointed-end elongation activities of VopF, revealing competition between these two V. cholerae effectors. These results suggest that bacterial effectors from different species that target the same host machinery or proteins may represent an effective but largely overlooked mechanism of indirect bacterial competition in host-associated microbial communities. Whether the proposed inhibition mechanism involves the actin cytoskeleton or other host cell compartments, such inhibition deserves investigation and may contribute to a documented scarcity of human enteric co-infections by different pathogenic bacteria. Full article

Background: Venous occlusion plethysmography (VOP) non-invasively measures forearm blood flow (FBF), whereas near-infrared spectroscopy (NIRS) assesses skeletal muscle oxygenation. Using these techniques has revealed sex differences in microvascular responses. However, it is not clear if NIRS and VOP results are interchangeable under various conditions like reactive hyperemia (RH). Our purpose was to evaluate sex-specific associations between FBF and NIRS-derived parameters: oxygenated hemoglobin, deoxygenated hemoglobin, total hemoglobin, and hemoglobin difference (O₂Hb, HHb, tHb, and HbDiff). Methods: In total, 29 adults (15 men) participated, and a strain-gauge was placed on the forearm for VOP and a NIRS device was distally attached. Slopes for FBF and NIRS parameters were quantified during venous occlusion intervals at rest and during RH. Pearson’s correlations were assessed between VOP and NIRS slopes. Intraclass correlation coefficients (ICC_2,1) examined the sex-specific consistency of the slopes at rest. p ≤ 0.05 was considered significant. Results: During RH, FBF was not correlated with O₂Hb (r = −0.126), HHb (r = 0.228), tHb (r = 0.061), or HbDiff (r = 0.046). Seemingly, there were no sex differences. Resting FBF and NIRS-derived variables, except for HbDiff, displayed suitable consistency as suggested by the reliability results (ICC_2,1 = 0.115–0.577). Conclusions: The NIRS values collected did not match the strain-gauge slopes. Individuals should practice caution when generating blood flow inferences from NIRS-based data during VOP. Full article

An electrical storm (ES) is defined as the presence of at least three episodes of sustained ventricular tachycardia or ventricular fibrillation within 24 h. This patient had a previously known arterial hypertension, type II diabetes mellitus, and chronic kidney disease and has presented to the Emergency Department (ED) with symptoms of retrosternal chest pain lasting for several hours prior. The initial 12-lead electrocardiogram revealed ST segment elevation in the anterior leads (V1–V6). Emergent coronary angiography revealed an acute occlusion of the proximal left anterior descending artery (pLAD) and percutaneous coronary intervention was performed with successful implantation of one drug-eluting stent in the pLAD. On day 8 of hospitalization, the patient developed a refractory ES for which he received 50 DC shocks and did not respond to multiple lines of antiarrhythmic medications. Due to a failure of medical therapy, we decided to implant a temporary pacemaker and initiate ventricular overdrive pacing (VOP) that was successful in terminating ES. Following electrical stabilization, the patient underwent a successful ICD implantation. This case demonstrates that VOP can contribute to hemodynamic and electrical stabilization of a patient that suffers from refractory ES and this treatment modality might serve as a temporary bridge to ICD implantation. Full article

This study investigated the effects of Lactiplantibacillus plantarum 75 (LAB 75) fermentation at 37 °C for 48 h on the pH, total soluble solids (TSS), colour, total titratable acidity (TTA), carotenoids, and bioactivities of cowpea leaf smoothies from three cultivars (VOP 1, VOP 3, and VOP 4). Fermentation reduced the pH from 6.57 to 5.05 after 48 h. The TTA increased with the fermentation period, whilst the TSS reduced. Fermentation of the smoothies resulted in the least colour changes (∆E) in VOP 1 after 48 h. Fermentation of cowpea smoothies (VOP 1, VOP 3, and VOP 4) improved the antioxidant capacity (FRAP, DPPH, and ABTS), which was attributed to the increase in total phenolic compounds and carotenoid constituents in all of the fermented cowpea smoothies. VOP 1 was further selected for analysis due to its high phenolic content and antioxidant activity. The VOP 1 smoothie fermented for 24 h showed the lowest reduction in TPC (11%) and had the highest antioxidant (FRAP, DPPH, and ABTS) activity. Ltp. plantarum 75 was viable and survived the harsh conditions of the gastrointestinal tract, and, hence, could be used as a probiotic. VOP 1 intestinal digesta showed significantly higher glucose uptake relative to the undigested and the gastric digesta, while the gastric phase had higher levels of α-amylase and α-glucosidase compared to the undigested samples. Full article

Masonry is a widespread construction system, but it is very prone to seismic damage. In Italy, almost 60% of residential buildings are constructed in masonry, and 85% of them were built before 1980 without specific design regulation; thus, there is the need for large-scale vulnerability assessment. When large stocks of residential buildings (>50–100) are involved, also in historical centers, seismic vulnerability analysis must resort to simplified and computer-aided methods. Among these, the best known analyze (i) the overall shear strength normalized to the weight; (ii) the activation coefficient of local mechanisms; and (iii) dimensionless indexes obtained from the weighted sum of scores associated with a set of vulnerability factors. The Vulnus procedure proposes a vulnerability function in the 3D space defined by these factors, namely V_IP, V_OP and V_V. The ‘mechanical’ indexes V_IP and V_OP determine the capacity of the building (in-plane and out-of-plane, respectively), whereas the ‘empirical’ index V_V sets the pace at which this capacity is reached and the uncertainty in its final value. The procedure considers the confidence level of the indexes by means of fuzzy set theory, which enables expression of the vulnerability in linguistic terms (e.g., ‘high’ or ‘low’), as well as through a fragility curve. In this paper, a web toolbox based on the Vulnus procedure, namely, Vulnus Web, is proposed. It enables the central archiving of data, improved interaction with the program code and a wider dissemination. The new procedure was applied to a masonry building hit by the Central Italy 2016 earthquake; both the vulnerability level assessed numerically and the damage prediction were in good accordance with the actual seismic performance of the building. Full article

Introduction: On the United States’ Organ Transplantation Waitlist, approximately 17 people die each day waiting for an organ. The situation continues to deteriorate as the discrepancy between harvested organs and the number of patients in need is increasing. Static cold storage is the clinical standard method for preserving a harvested organ but is associated with several drawbacks. Machine perfusion of an organ has been shown to improve preservation quality as well as preservation time over static cold storage. While there are machine perfusion devices clinically available, they are costly and limited to specific organs and preservation solutions. This study presents a versatile oxygenating perfusion system (VOPS) that supplies oxygen and pulsatile perfusion. Materials and Methods: Experiments evaluated the system’s performance with a human kidney mimicking hydraulic analog using multiple compressed oxygen supply pressures and aqueous solutions with viscosities ranging from 1 to 6.5 cP, which simulated viscosities of commonly used organ preservation solutions. Results and Conclusions: The VOPS produced mean flow rates ranging from 0.6 to 28.2 mL/min and perfusion pressures from 4.8 to 96.8 mmHg, which successfully achieved the desired perfusion parameters for human kidneys. This work provides evidence that the VOPS described herein has the versatility to perfuse organs using many of the clinically available preservation solutions. Full article

The actin cytoskeleton lies at the heart of many essential cellular processes. There are hundreds of proteins that cells use to control the size and shape of actin cytoskeletal networks. As such, various pathogens utilize different strategies to hijack the infected eukaryotic host actin dynamics for their benefit. These include the control of upstream signaling pathways that lead to actin assembly, control of eukaryotic actin assembly factors, encoding toxins that distort regular actin dynamics, or by encoding effectors that directly interact with and assemble actin filaments. The latter class of effectors is unique in that, quite often, they assemble actin in a straightforward manner using novel sequences, folds, and molecular mechanisms. The study of these mechanisms promises to provide major insights into the fundamental determinants of actin assembly, as well as a deeper understanding of host–pathogen interactions in general, and contribute to therapeutic development efforts targeting their respective pathogens. This review discusses mechanisms and highlights shared and unique features of actin assembly by pathogen effectors that directly bind and assemble actin, focusing on eukaryotic actin nucleator functional mimics Rickettsia Sca2 (formin mimic), Burkholderia BimA (Ena/VASP mimic), and Vibrio VopL (tandem WH2-motif mimic). Full article

Vibrio parahaemolyticus, one of the most common foodborne pathogenic bacteria that forms biofilms, is a persistent source of concern for the food industry. The food production chain employs a variety of methods to control biofilms, although none are completely successful. This study aims to evaluate the effectiveness of quercetin as a food additive in reducing V. parahaemolyticus biofilm formation on stainless-steel coupons (SS) and hand gloves (HG) as well as testing its antimicrobial activities. With a minimum inhibitory concentration (MIC) of 220 µg/mL, the tested quercetin exhibited the lowest bactericidal action without visible growth. In contrast, during various experiments in this work, the inhibitory efficacy of quercetin at sub-MICs levels (1/2, 1/4, and 1/8 MIC) against V. parahaemolyticus was examined. Control group was not added with quercetin. With increasing quercetin concentration, swarming and swimming motility, biofilm formation, and expression levels of target genes linked to flagellar motility (flaA, flgL), biofilm formation (vp0952, vp0962), virulence (VopQ, vp0450), and quorum-sensing (aphA, luxS) were all dramatically suppressed. Quercetin (0–110 μg/mL) was investigated on SS and HG surfaces, the inhibitory effect were 0.10–2.17 and 0.26–2.31 log CFU/cm², respectively (p < 0.05). Field emission scanning electron microscopy (FE-SEM) corroborated the findings because quercetin prevented the development of biofilms by severing cell-to-cell contacts and inducing cell lysis, which resulted in the loss of normal cell shape. Additionally, there was a significant difference between the treated and control groups in terms of motility (swimming and swarming). According to our research, quercetin produced from plants should be employed as an antibiofilm agent in the food sector to prevent the growth of V. parahaemolyticus biofilms. These results indicate that throughout the entire food production chain, bacterial targets are of interest for biofilm reduction with alternative natural food agents in the seafood industry. Full article

A protonic ceramic fuel cell (PCFC) has great potential for medium temperature power generation. Its working process, however, is complicated and quite different from the traditional oxygen ionic solid oxide fuel cell (O²⁻-SOFC) and proton exchange membrane fuel cell (PEMFC). In this paper, a multi-physical model for the PCFC with H⁺/e⁻/O²⁻ mixed conducting cathode is established, in which the fuel- and oxidant-diffusing processes; electron-, oxygen ion-, and proton-conducting processes; three electrochemical reactions; and their coupling working details are carefully considered. Taking Ni-BZCY/BZCY/BZCY-LSCF PCFC as an example, the validation of the model is well verified by good agreements with the experiment i_op-V_op curves at different temperatures. The result shows that the cathodic electrochemical reactions will be concentrated to a small thickness near the electrolyte because of the greatly decreased ionic conductivity compared with the high electronic conductivity at an intermediate temperature. O²⁻ within the PCFC cathode is only an intermediate transform substance between the electrons and protons. Thus, there is a peak oxygen ion current distribution within the composite cathode of PCFC. The cathodic oxygen reduction half reaction is found to be a key factor to dominate the total PCFC voltage loss at the intermediate temperature zone. The concentration polarization of anode-supported PCFC is small, due to the vapors that are generated in the cathode side instead of anode side. Full article

The need for pelvic treatment in patients with node-positive vulvar cancer (VSCC) and the value of pelvic lymphadenectomy (LAE) as a staging procedure to plan adjuvant radiotherapy (RT) is controversial. In this retrospective, multicenter analysis, 306 patients with primary node-positive VSCC treated at 33 gynecologic oncology centers in Germany between 2017 and 2019 were analyzed. All patients received surgical staging of the groins; nodal status was as follows: 23.9% (73/306) pN1a, 23.5% (72/306) pN1b, 20.4% (62/306) pN2a/b, and 31.9% (97/306) pN2c/pN3. A total of 35.6% (109/306) received pelvic LAE; pelvic nodal involvement was observed in 18.5%. None of the patients with nodal status pN1a or pN1b and pelvic LAE showed pelvic nodal involvement. Taking only patients with nodal status ≥pN2a into account, the rate of pelvic involvement was 25%. In total, adjuvant RT was applied in 64.4% (197/306). Only half of the pelvic node-positive (N+) patients received adjuvant RT to the pelvis (50%, 10/20 patients); 41.9% (122/291 patients) experienced recurrent disease or died. In patients with histologically-confirmed pelvic metastases after LAE, distant recurrences were most frequently observed (7/20 recurrences). Conclusions: A relevant risk regarding pelvic nodal involvement was observed from nodal status pN2a and higher. Our data support the omission of pelvic treatment in patients with nodal status pN1a and pN1b. Full article

Vibrio parahaemolyticus is considered one of the most relevant pathogenic marine bacteria with a range of virulence factors to establish food-related gastrointestinal infections in humans. Cinnamaldehyde (CNMA) and some of its derivatives have antimicrobial and antivirulence activities against several bacterial pathogens. This study examined the inhibitory effects of CNMA and its derivatives on biofilm formation and the virulence factors in Vibrio species, particularly V. parahaemolyticus. CNMA and ten of its derivatives were initially screened against V. parahaemolyticus biofilm formation, and their effects on the production of virulence factors and gene expression were studied. Among the CNMA derivatives tested, 4-nitrocinnamaldehyde, 4-chlorocinnamaldehyde, and 4-bromocinnamaldehyde displayed antibacterial and antivirulence activities, while the backbone CNMA had weak effects. The derivatives could prevent the adhesion of V. parahaemolyticus to surfaces by the dose-dependent inhibition of cell surface hydrophobicity, fimbriae production, and flagella-mediated swimming and swarming phenotypes. They also decreased the protease secretion required for virulence and indole production, which could act as an important signal molecule. The expression of QS and biofilm-related genes (aphA, cpsA, luxS, and opaR), virulence genes (fliA, tdh, and vopS), and membrane integrity genes (fadL, and nusA) were downregulated in V. parahaemolyticus by these three CNMA analogs. Interestingly, they eliminated V. parahaemolyticus and reduced the background flora from the squid surface. In addition, they exhibited similar antimicrobial and antibiofilm activities against Vibrio harveyi. This study identified CNMA derivatives as potential broad-spectrum antimicrobial agents to treat biofilm-mediated Vibrio infections and for surface disinfection in food processing facilities. Full article

The injection of apparent power to self-consumption buses generates voltage variations during network operation, which, when properly monitored, could support voltage regulation and control. In this paper, we propose a linear sensitivity modelling, quite useful for studies of voltage regulation with distributed energy resources (DER). This modelling consists of two analytical improvement steps: first, a full formulation for the voltage deviations, and second, the influence of line capacitance as Q-injections at the points of common couplings (PCCs). Our proposal is based on the linear topological sensitivity of an existing network (as a function of the line parameters X, R, and Bc), branch power flow (active–reactive power (P-Q)), and power injections at the PCCs. Here, the linear sensitivity algorithm is applied to a modified IEEE 33-bus distribution system to demonstrate its extended effectiveness to voltage monitoring and control scenarios. Its application estimates and compensates in a better way the voltage deviations with regard to the operating desired voltage (|V|_op) constraints, using distributed power injections at the PCCs. Numerical results always showed a curtailment of the relative error against common simplifications of the electrical modelling in steady-state, thus simulating two critical scenarios of operation production–consumption for the existing system response. The proposed algorithm was validated considering as reference the voltage profile outputs of the load flow analysis, using the Newton–Raphson method via DIgSILENT, in terms of its accuracy, silhouette shape along the feeder and with regard to the application of reactive compensation as an analytical case study for voltage improvement in active distribution networks. Full article

This paper addresses the problem of optimizing the voltage profile of radially-operated distribution systems by acting on the active and reactive powers provided by distributed energy resources (DERs). A novel voltage optimization procedure is proposed by adopting a decentralized control strategy. To this aim, a centralized voltage optimization problem (VOP), minimizing the distance of all the nodal voltages from their reference values, is firstly formulated as a strictly-convex quadratic program. Then, the centralized VOP is rewritten by partitioning the network into voltage control zones (VCZs) with pilot nodes. To overcome the lack of strictly convexity determined by the reduction to the pilot nodes, the dual centralized VOP working on the augmented Lagrangian function is reformulated and iteratively solved by the method of multipliers. Finally, a fully-distributed VOP solution is obtained by applying a distributed algorithm based on the auxiliary problem principle, which allows for solving in each VCZ a quadratic programming problem of small dimension and to drive the VCZ solutions toward the overall optimum by an iterative coordination process that requires to exchange among the VCZs only scalar values. The effectiveness and feasibility of the proposed method have been demonstrated via numerical tests on the IEEE 123-bus system. Full article