Search Results (5,659)

Background/Objectives: Antimicrobial resistance (AMR) contributes to millions of deaths globally each year, creating an urgent need for new therapeutic agents. Antimicrobial peptides (AMPs) have emerged as promising candidates due to their potential to combat AMR pathogens. This study aimed to evaluate the antimicrobial activity of an AMP from a soil-derived bacterial isolate against Gram-negative bacteria. Method: Soil bacteria were isolated and screened for antimicrobial activity. The bioactive peptide was purified and determined its structure and antimicrobial efficacy. Genomic analysis was conducted to predict the biosynthetic gene clusters (BGCs) responsible for AMP production. Results: Genomic analysis identified the isolate as Paenibacillus sp. Na14, which exhibited low genomic similarity (61.0%) to other known Paenibacillus species, suggesting it may represent a novel species. The AMP from the Na14 strain exhibited heat stability up to 90 °C for 3 h and retained its activity across a broad pH range from 3 to 11. Structural analysis revealed that the Na14 peptide consisted of 14 amino acid residues, adopting an α-helical structure. This peptide exhibited bactericidal activity at concentrations of 2–4 µg/mL within 6–12 h, and its killing rate was concentration-dependent. The peptide was found to disrupt the bacterial membranes. The Na14 peptide shared 64.29% sequence similarity with brevibacillin 2V, an AMP from Brevibacillus sp., which also belongs to the Paenibacillaceae family. Genomic annotation identified BGCs associated with secondary metabolism, with a particular focus on non-ribosomal peptide synthetase (NRPS) gene clusters. Structural modeling of the predicted NRPS enzymes showed high similarity to known NRPS modules in Brevibacillus species. These genomic findings provide evidence supporting the similarity between the Na14 peptide and brevibacillin 2V. Conclusions: This study highlights the discovery of a novel AMP with potent activity against Gram-negative pathogens and provides new insight into conserved AMP biosynthetic enzymes within the Paenibacillaceae family. Full article

Cystic fibrosis (CF), the most common hereditary lung disease in Caucasians, is caused by dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR). We evaluated CFTR function using a newly developed Ussing chamber system, the Multi Trans Epithelial Current Clamp (MTECC), in an in vitro model of human airway epithelia. Air–liquid interface (ALI) cultures were established from nasal brushings of healthy controls (HC) and CF patients with biallelic CFTR variants. ALI layer thickness was similar between groups (HC: 62 ± 13 µm; CF: 55 ± 9 µm). Immunofluorescence showed apical CFTR expression in HC, but reduced or absent signal in CF cultures. MTECC enabled continuous measurement of transepithelial resistance (Rt), potential difference (PD), and conductance (G_t). G_t was significantly reduced in CF cultures compared to HC (0.825 ± 0.024 vs. −0.054 ± 0.016 mS/cm²), indicating impaired cAMP-inducible ion transport by CFTR. Treatment of CF cultures with elexacaftor, tezacaftor, and ivacaftor (Trikafta^®) increased G_t, reflecting partial restoration of CFTR function. These findings demonstrate the utility of MTECC in detecting functional differences in CFTR activity and support its use as a platform for evaluating CFTR-modulating therapies. Our model may contribute to the development of personalized treatment strategies for CF patients. Full article

Protein enzymes are highly efficient catalysts that exhibit adaptability and selectivity under diverse biological conditions. In some organisms, such as bacteria, structurally similar enzymes, for instance, shikimate kinase (SK) and adenylate kinase (AK), coexist and act on chemically related ligands. This raises the question of whether these enzymes can accommodate and potentially react with each other’s ligands. In this study, we investigate the stability of non-cognate ligand binding in SK and explore whether external electric fields (EFs) can modulate this interaction, leading to cross-reactivity in SK. Using molecular dynamics simulations, we assess the structural integrity of SK and the binding behavior of ATP and AMP under EF-off and EF-on cases. Our results show that EFs enhance protein structure stability, stabilize non-cognate ligands in the binding pocket, and reduce local energetic frustration near the R116 residue located in the binding site. In addition to this, dimensionality reduction analyses reveal that EFs induce more coherent protein motions and reduce the number of metastable states. Together, these findings suggest that external EFs can reshape enzyme–ligand interactions and may serve as a tool to modulate enzymatic specificity and functional promiscuity. Thus, we provide computational evidence that supports the concept of using an EF as a tunable parameter in enzyme engineering and synthetic biology. However, further experimental investigation would be valuable to assess the reliability of our computational predictions. Full article

Gastric cancer (GC) is among the most common and deadliest types of cancer, with a poor prognosis primarily due to late-stage detection and the presence of cancer stem cells (CSCs). This study investigates the mechanisms regulating extracellular adenosine levels in gastric cancer stem-like cells (GCSCs) derived from the MKN-74 cell line. Our results show that GCSCs release more ATP into the extracellular medium and exhibit higher levels of CD39 expression, which enables them to hydrolyze a greater amount of ATP. Furthermore, we also found that GCSCs possess a greater capacity to hydrolyze AMP, primarily due to the activity of the CD73 protein, with no significant changes in CD73 transcripts and protein levels between GCSCs and differentiated cells. Additionally, adenosine transport is primarily mediated by members of the equilibrative nucleoside transporter (ENT) family in GCSCs, where a significant increase in the expression level of the ENT2 protein is observed compared to non-GCSCs MKN-74 cells. These findings suggest that targeting the adenosine metabolism pathway in GCSCs could be a potential therapeutic strategy for gastric cancer. Full article

Cefepime-enmetazobactam is a novel β-lactam/β-lactamase inhibitor combination showing good activity against multidrug-resistant (MDR) Gram-negative bacteria producing a variety of β-lactamases. In this systematic review, we aimed to evaluate the available data on resistance to this drug. We performed a thorough search of four databases (Embase, PubMed, Scopus, and Web of Science), as well as backward citation searching, to identify studies containing data on resistance to cefepime-enmetazobactam. The data were extracted and analyzed according to the breakpoints established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Food and Drug Administration (FDA), or the specific breakpoints reported by the authors of the respective studies. Analysis based on the type of lactamases produced by the isolates was also performed. Ten studies reported in vitro susceptibility testing and mechanisms of antimicrobial resistance. The total number of isolates was 15,408. The activity of cefepime-enmetazobactam against β-lactamase-producing isolates was variable. The resistance of the studied extended-spectrum β-lactamase (ESBL)-producing and ampicillin C β-lactamase (AmpC)-producing isolates was low (0–2.8% and 0%, respectively). The resistance was higher among oxacillinase-48 β-lactamase (OXA-48)-producing and Klebsiella pneumoniae carbapenemase (KPC)-producing isolates (3.4–13.2% and 36.7–57.8%, respectively). High resistance was noted among metallo-β-^lactamase (MBL)-producing isolates (reaching 87.5% in one study), especially those producing New Delhi metallo-β-lactamase (NDM) and Verona integron-encoded metallo-β-lactamase (VIM), which had the highest rates of resistance. The high activity of cefepime-enmetazobactam against Enterobacterales and selected lactose non-fermenting Gram-negative pathogens, including ESBL-producing and AmpC-producing isolates, makes it a potential carbapenem-sparing agent. The drug should be used after in vitro antimicrobial susceptibility testing in patients with infections caused by OXA-48, KPC, and MBL-producing isolates. Full article

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a systemic ciliopathy resulting from loss-of-function mutations in the PKD1 and PKD2 genes, which encode polycystin-1 (PC1) and polycystin-2 (PC2), respectively. PC1 and PC2 regulate mechanosensation, calcium signaling, and key pathways controlling tubular epithelial structure and function. Loss of PC1/PC2 disrupts calcium homeostasis, elevates cAMP, and activates proliferative cascades such as PKA–B-Raf–MEK–ERK, mTOR, and Wnt, driving cystogenesis via epithelial proliferation, impaired apoptosis, fluid secretion, and fibrosis. Recent evidence also implicates novel signaling axes in ADPKD progression including, the Hippo pathway, where dysregulated YAP/TAZ activity enhances c-Myc-mediated proliferation; the stimulator of interferon genes (STING) pathway, which is activated by mitochondrial DNA release and linked to NF-κB-driven inflammation and fibrosis; and the TWEAK/Fn14 pathway, which mediates pro-inflammatory and pro-apoptotic responses via ERK and NF-κB activation in tubular cells. Mitochondrial dysfunction, oxidative stress, and maladaptive extracellular matrix remodeling further exacerbate disease progression. A refined understanding of ADPKD’s complex signaling networks provides a foundation for precision medicine and next-generation therapeutics. This review gathers recent molecular insights and highlights both established and emerging targets to guide targeted treatment strategies in ADPKD. Full article

Fyn is widely involved in diverse cellular physiological processes, including cell growth and survival, and has been implicated in the regulation of energy metabolism and the pathogenesis of diabetes mellitus through multiple pathways. Fyn plays a role in increasing fat accumulation and promoting insulin resistance, and it also contributes to the development of diabetic complications such as diabetic kidney disease and diabetic retinopathy. The primary mechanism by which Fyn modulates lipid metabolism is that it inhibits AMP-activated protein kinase (AMPK). Additionally, it affects energy homeostasis through regulating specific signal pathways affecting lipid metabolism including pathways related to CD36, through enhancement of adipocyte differentiation, and through modulating insulin signal transduction. Inflammatory stress is one of the fundamental mechanisms in diabetes mellitus and its complications. Fyn also plays a role in inflammatory stress-related signaling cascades such as the Akt/GSK-3β/Fyn/Nrf2 pathway, exacerbating inflammation in diabetes mellitus. Therefore, Fyn emerges as a promising therapeutic target for regulating glucolipid metabolism and alleviating type 2 diabetes mellitus. This review synthesizes research on the role of Fyn in the regulation of energy metabolism and the development of diabetes mellitus, while exploring its specific regulatory mechanisms. Full article

Antimicrobial resistance (AMR) is a growing global health threat, with wild birds increasingly recognized as potential reservoirs of resistant pathogens and as sentinels of environmental AMR. This study investigated the occurrence and AMR profiles of Gram-negative bacteria isolated from wild birds that died at the Wildlife Rescue Center in Vanzago, Lombardy, in 2024. Cloacal swabs were collected from 112 birds representing various ecological categories. A total of 157 Gram-negative bacteria were isolated and identified, including clinically relevant genera and species, such as Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Salmonella spp., Pseudomonas aeruginosa, and Acinetobacter baumannii. Antimicrobial susceptibility testing revealed resistance to first-line and critically important antimicrobials, including those exclusively authorized for human use. Notably, a phenotype compatible with Extended-Spectrum Beta-Lactamase (ESBL) production was detected in four out of ten (40%) K. pneumoniae isolates. In addition, 20 out of the 157 (12.7%) isolated bacteria phenotypically exhibited a resistance profile indicative of AmpC beta-lactamase (AmpC) production, including Enterobacter spp. and P. aeruginosa. Resistance patterns were particularly interesting in birds with carnivorous, scavenging, or migratory-associated behaviors. These findings highlight the role of wild birds in the ecology and dissemination of antimicrobial-resistant bacteria (ARB) and highlight the need for wildlife-based AMR monitoring programs as part of a One Health approach. Full article

The Anti-Müllerian hormone (AMH) is widely recognized for promoting Müllerian duct regression in higher vertebrates and regulating key reproductive functions like steroidogenesis, folliculogenesis, and Leydig cell development. In teleost fish, which lack Müllerian ducts, Amh primarily influences male reproductive functions, including sex determination, testis differentiation, and germ cell proliferation. In adult fish, Amh supports gonad development and spermatogenesis, but its role in teleost gonadal physiology remains largely underexplored. This study reveals a novel steroidogenic function in the European sea bass (Dicentrarchus labrax) using in vitro testis culture, in vivo plasmid injection, and cell-based transactivation assays. The Amh-induced significant increase in androgen levels was also confirmed in Japanese medaka (Oryzias latipes) treated with recombinant sea bass Amh. Beyond activating the canonical Smad pathway, Amh also triggered the cAMP/PKA signalling pathway via its cognate type II receptor, Amhr2. Inhibitors of these pathways independently and synergistically counteracted Amh-induced CRE-Luc activity, indicating pathway crosstalk. Moreover, inhibition of the cAMP pathway suppressed Amh-induced androgen production in testis cultures, emphasizing the crucial role of protein kinase A in mediating Amh steroidogenic action. These findings uncover a novel steroidogenic function of Amh in teleosts and highlight its broader role in male reproductive physiology. Full article

This paper presents a microcontroller-based technique for accurately measuring resistive sensors over a wide dynamic range using an adaptive constant current source. Unlike conventional voltage dividers or fixed-current methods—often limited by reduced resolution and saturation when sensor resistance varies across several decades—the proposed system dynamically adjusts the excitation current to maintain optimal Analog-to-Digital Converter (ADC) input conditions. The measurement circuit employs a fixed reference resistor and an inverting amplifier configuration, where the excitation current is generated by one or more pulse-width modulated (PWM) signals filtered through low-pass RC networks. A microcontroller selects the appropriate PWM channel to ensure that the output voltage remains within the ADC’s linear range. To support multiple sensors, an analog switch enables sequential measurements using the same dual-PWM current source. The full experimental implementation uses four op-amps to support modularity, buffering, and dual-range operation. Experimental results show accurate measurement of resistances from 1 kΩ to 100 kΩ, with maximum relative errors of 0.15% in the 1–10 kΩ range and 0.33% in the 10–100 kΩ range. The method provides a low-cost, scalable, and digitally controlled solution suitable for embedded resistive sensing applications without the need for high-resolution ADCs or programmable gain amplifiers. Full article

The white-spotted jellyfish, Phyllorhiza punctata, is an invasive species with significant ecological and economic relevance spreading across various regions. While its ecological impact is well-documented, its molecular and biochemical characteristics remain poorly understood. In this study, we integrate proteomic data generated by LC-MS/MS with publicly available transcriptomic information to characterize P. punctata, analyzing differential protein expression across three distinct tissues: oral arms, mantle, and gonads. A total of 2764 proteins and 25,045 peptides were identified, including several venom components such as jellyfish toxins (JFTs) and phospholipase A2 (PLA2), which were further investigated and compared to toxins from other species. Enrichment analyses revealed clear tissue-specific functions. Additionally, deep learning and machine learning tools identified 274 promising AMP candidates, including the α-helical, β-sheet, and αβ-motif peptides. This dataset provides new insights into the protein composition of P. punctata and highlights strong AMP candidates for further characterization, underscoring the biotechnological potential of underexplored cnidarian species. Full article

Background/Objectives: The clinical potential of antimicrobial peptides (AMPs) against dual threats like antimicrobial resistance (AMR) and cancer is often limited by their high host cell toxicity. Here, we focused on brevinin-2OS (B2OS), a novel peptide from the skin of Odorrana schmackeri with potent haemolytic activity. The objective was to study the structure–activity relationship and optimise the safety via targeted modifications. Methods: A dual-modification strategy involving C-terminal truncation and subsequent N-terminal D-amino acid substitution was employed. The bioactivities and safety profiles of the resulting analogues were evaluated using antimicrobial, haemolysis, and cytotoxicity assays. Result: Removal of the rana box in B2OS(1-22)-NH₂ substantially reduced haemolysis while maintaining bioactivities. Remarkably, the D-leucine substitution in [D-Leu²]B2OS(1-22)-NH₂ displayed a superior HC₅₀ value of 118.1 µM, representing a more than ten-fold improvement compared to its parent peptide (HC₅₀ of 10.44 µM). This optimised analogue also demonstrated faster bactericidal kinetics and enhanced membrane permeabilisation, leading to a greater than 22-fold improvement in its therapeutic index against Gram-positive bacteria. Conclusions: The C-terminal rana box is a primary determinant of toxicity rather than a requirement for activity in the B2OS scaffold. The engineered peptide [D-Leu²]B2OS(1-22)-NH₂ emerges as a promising lead compound, and this dual-modification strategy provides a powerful design principle for developing safer, more effective peptide-based therapeutics. Full article

Background: Signaling pathways like those depending on cAMP/PKA, calcium/calmodulin/CaMK, MEK-1/MAPK or PI3K/Akt have been described to modulate suprachiasmatic nucleus (SCN) neuronal signaling via influencing transcription factors like CREB. Here, we analyzed the effect of cyclic nucleotide phosphodiesterase inhibitors and structurally similar substances commonly used as autophagy modulators on a cell line stably expressing a cyclic nucleotide element-driven luciferase reporter. Methods: We used an SCN cell line stably transfected with a CRE-luciferase reporter (SCNCRE) to evaluate signaling and vitality responses to various isoform-selective PDE inhibitors and autophagy modulators to evaluate the mechanism of action of the latter. Results: In this study the different impacts of common PDE inhibitors and autophagy modulators on CRE-luciferase activity applied alone and in combination with known CRE-luciferase activating agents showed that (1) PDE3, 4 and 5 are present in SCNCRE cells, with (2) PDE3 being the most active and (3) the autophagy inhibitor 3-Methyladenin (3-MA) displaying PDE inhibitor-like behavior. Conclusions: Experiments provide evidence that, in addition to the extracellular signaling pathways components shown before to be involved in CRE-luciferase activity regulation like cAMP analogs, adenylate cyclase activators and beta-adrenoceptor agonists, cyclic nucleotide metabolism as realized by phosphodiesterase activity, or molecule/agents influencing processes like autophagy or inflammation, modulate transcriptional CRE-dependent activity in these cells. Specifically, we provide evidence that the autophagy inhibitor 3-MA, given that PDEs are expressed, may also act as a PDE inhibitor and inducer of CRE-mediated transcriptional activity. Full article

Antimicrobial peptides (AMPs) provide a robust alternative to conventional antibiotics, combating escalating microbial resistance through their diverse functions and broad pathogen-targeting abilities. While current deep learning technologies enhance AMP generation, they face challenges in developing multifunctional AMPs due to intricate amino acid interdependencies and limited consideration of diverse functional activities. To overcome this challenge, we introduce a novel de novo multifunctional AMP design framework that enhances a Feedback Generative Adversarial Network (FBGAN) by integrating a global quantitative AMP activity regression module and a multifunctional-attribute integrated prediction module. This integrated approach not only facilitates the automated generation of potential AMP candidates, but also optimizes the network’s ability to assess their multifunctionality. Initially, by integrating an effective pre-trained regression and classification model with feedback-loop mechanisms, our model can not only identify potential valid AMP candidates, but also optimizes computational predictions of Minimum Inhibitory Concentration (MIC) values. Subsequently, we employ a combinatorial predictor to simultaneously identify and predict five multifunctional AMP bioactivities, enabling the generation of multifunctional AMPs. The experimental results demonstrate the efficiency of generating AMPs with multiple enhanced antimicrobial properties, indicating that our work can provide a valuable reference for combating multi-drug-resistant infections. Full article

The innate immune response is an important defense against invading pathogens. Stimulator of interferon gene (STING) plays an important role in the cyclic GMP-AMP synthase (cGAS)-mediated activation of type I IFN responses. However, some viruses have evolved the ability to inhibit the function of STING and evade the host antiviral defenses. Understanding both the mechanism of action and the viruses targets of STING effector is important because of their importance to evade the host antiviral defenses. In this study, the STING (IpSTING) of Ictalurus punctatus was first identified and characterized. Subsequently, the yeast two-hybrid system (Y2HS) was used to screen for proteins from channel catfish virus (CCV, Ictalurid herpesvirus 1) that interact with IpSTING. The ORFs of the CCV were cloned into the pGBKT7 vector and expressed in the AH109 yeast strain. The bait protein expression was validated by autoactivation, and toxicity investigation compared with control (AH109 yeast strain transformed with empty pGBKT7 and pGADT7 vector). Two positive candidate proteins, ORF41 and ORF65, were identified through Y2HS screening as interacting with IpSTING. Their interactions were further validated using co-immunoprecipitation (Co-IP). This represented the first identification of interactions between IpSTING and the CCV proteins ORF41 and ORF65. The data advanced our understanding of the functions of ORF41 and ORF65 and suggested that they might contribute to the evasion of host antiviral defenses. However, the interaction mechanism between IpSTING, and CCV proteins ORF41 and ORF65 still needs to be further explored. Full article