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Food-borne transmission is a recognized route for many viruses associated with gastrointestinal, hepatic, or neurological diseases. Therefore, it is essential to identify new bioactive compounds with broad-spectrum antiviral activity to exploit innovative solutions against these hazards. Recently, antimicrobial peptides (AMPs) have been recognized as promising antiviral agents. Indeed, while the antibacterial and antifungal effects of these molecules have been widely reported, their use as potential antiviral agents has not yet been fully investigated. Herein, the antiviral activity of previously identified or newly designed AMPs was evaluated against the non-enveloped RNA viruses, hepatitis A virus (HAV) and murine norovirus (MNV), a surrogate for human norovirus. Moreover, specific assays were performed to recognize at which stage of the viral infection cycle the peptides could function. The results showed that almost all peptides displayed virucidal effects, with about 90% of infectivity reduction in HAV or MNV. However, the decapeptide RiLK1 demonstrated, together with its antibacterial and antifungal properties, a notable reduction in viral infection for both HAV and MNV, possibly through direct interaction with viral particles causing their damage or hindering the recognition of cellular receptors. Hence, RiLK1 could represent a versatile antimicrobial agent effective against various foodborne pathogens including viruses, bacteria, and fungi. [ABSTRACT FROM AUTHOR]

Antimicrobial activity of many AMPs can be improved by lysine-to-arginine substitution due to a more favourable interaction of arginine guanidinium moiety with bacterial membranes. In a previous work, the structural and functional characterization of an amphipathic antimicrobial peptide named RiLK1, including lysine and arginine as the positively charged amino acids in its sequence, was reported. Specifically, RiLK1 retained its β-sheet structure under a wide range of environmental conditions (temperature, pH, and ionic strength), and exhibited bactericidal activity against Gram-positive and Gram-negative bacteria and fungal pathogens with no evidence of toxicity on mammalian cells. To further elucidate the influence of a lysine-to-arginine replacement on RiLK1 conformational properties, antimicrobial activity and peptide-liposome interaction, a new RiLK1- derivative, named RiLK3, in which the lysine is replaced with an arginine residue, was projected and characterised in comparison with its parental compound. The results evidenced that lysine-to-arginine mutation not only did not assure an improvement in the antimicrobial potency of RiLK1 in terms of bactericidal, virucidal and fungicidal activities, but rather it was completely abolished against the hepatitis A virus. Therefore, RiLK1 exhibited a wide range of antimicrobial activity like other cationic peptides, although the exact mechanisms of action are not completely understood. Moreover, tryptophan fluorescence measurements confirmed that RiLK3 bound to negatively charged lipid vesicles with an affinity lower than that of RiLK1, although no substantial differences from the structural and self-assembled point of view were evidenced. Therefore, our findings imply that antimicrobial efficacy and selectivity are affected by several complex and interrelated factors related to substitution of lysine with arginine, such as their relative proportion and position. In this context, this study could provide a better rationalisation for the optimization of antimicrobial peptide sequences, paving the way for the development of novel AMPs with broad applications. [ABSTRACT FROM AUTHOR]

Fresh fishery products are highly perishable foods mainly due to their high-water content and high level of pH which act as promoters of spoilage processes. In these matrices, the deterioration phenomena are the result of the action of oxidative, and enzymatic processes due in part to the presence of specific microorganisms. Indeed, the microbial communities responsible for spoilage are a small fraction of the flora detectable in the fish and are known as specific spoilage organisms (SSOs). In the last decades, the scientific community has worked to achieve the ambitious goal of reducing the impact of microbial deterioration on food losses through innovative solutions, including antimicrobial packaging. The goal of this study was to evaluate the efficacy of an active polypropylene (PP)- based packaging functionalized with the antimicrobial peptide 1018K6 to extend the shelf life of dolphinfish burgers (Coryphaena hippurus) by evaluating its effect on sensorial and microbiological profile. The microbiological results showed an evident antimicrobial activity of the active packaging against hygiene indicator microorganisms and SSOs, recording a reduction of about 1 Log (CFU/g) of their concentrations compared to those of the control groups. Furthermore, a significant influence of functionalized packaging on the organoleptic characteristics was noted, accentuating the differences in freshness between the two experimental groups. This work confirmed the hypothesis of considering antimicrobial packaging as a potential tool capable of slowing down surface microbial replication and, therefore, extending the shelf-life and improving the health and hygiene aspect of fresh fish products. [ABSTRACT FROM AUTHOR]

Superoxide dismutase (SOD) is a fundamental antioxidant enzyme that neutralises superoxide ions, one of the main reactive oxygen species (ROS). Extremophile organisms possess enzymes that offer high stability and catalytic performances under a wide range of conditions, thus representing an exceptional source of biocatalysts useful for industrial processes. In this study, SODs from the thermo-halophilic Aeropyrum pernix (SODAp) and the thermo-acidophilic Saccharolobus solfataricus (SODSs) were heterologously expressed in transgenic tomato cell cultures. Cell extracts enriched with SODAp and SODSs showed a remarkable resistance to salt and low pHs, respectively, together with optimal activity at high temperatures. Moreover, the treatment of tuna fillets with SODAp-extracts induced an extension of the shelf-life of this product without resorting to the use of illicit substances. The results suggested that the recombinant plant extracts enriched with the extremozymes could find potential applications as dietary supplements in the nutrition sector or as additives in the food preservation area, representing a more natural and appealing alternative to chemical preservatives for the market. [ABSTRACT FROM AUTHOR]

Fresh products are characterized by reduced shelf-life because they are an excellent growth medium for a lot of microorganisms. Therefore, the microbial spoilage causing significant food supply losses has become an enormous economic and ethical problem worldwide. The antimicrobial packaging is offering a viable solution to tackle this economic and safety issue by extending the shelf-life and improving the quality and safety of fresh products. The goal of this study was to investigate the effects of a food contact surface of polyethylene terephthalate (PET) functionalized with the previously characterized antimicrobial peptide mitochondrial-targeted peptide 1 (MTP1), in reducing the microbial population related to spoilage and in providing the shelf-life stability of different types of fresh foods such as ricotta cheese and buffalo meat. Modified polymers were characterized concerning the procedure of plasma-activation by water contact angle measurements and Fourier transform infrared spectroscopy measurements in attenuated total reflection mode (ATR-FTIR). Results showed that the MTP1-PETs provided a strong antimicrobial effect for spoilage microorganisms with no cytotoxicity on a human colon cancer cell line. Finally, the activated polymers revealed high storage stability and good reusability. This study provided valuable information to develop alternative antimicrobial packaging for enhancing and extending the microbial quality and safety of perishable foods during storage. [ABSTRACT FROM AUTHOR]

The oxidative challenge represents an important factor affecting the adaptive strategies in Antarctic fish, but their impact on the protein degradation machinery still remains unclear. The previous analysis of the first 26S proteasome from the Antarctic red-blooded fish Trematomus bernacchii, evidenced improved antioxidant functions necessary to counteract the environmental pro-oxidant conditions. The purpose of this work was to carry out a study on 26S proteasomes from the temperate red-blooded Dicenthrarcus labrax and the icefish Chionodraco hamatus in comparison with the isoform already described from T. bernacchii, to better elucidate the cold-adapted physiological functions of this complex. Therefore, the 26S isoforms were isolated and the complementary DNAs (cDNAs) codifying the catalytic subunits were cloned. The biochemical characterization of Antarctic 26S proteasomes revealed their significantly higher structural stability and resistance to H2O2 with respect to that of the temperate counterpart, as also suggested by a comparative modeling analysis of the catalytic subunits. Moreover, in contrast to that observed in T. bernacchii, the 26S systems from C. hamatus and D. labrax were incapable to hydrolyze oxidized proteins in a ubiquitin-independent manner. Therefore, the 'uncommon' properties displayed by the Antarctic 26S proteasomes can mirror the impact exercised by evolutionary pressure in response to richly oxygenated environments [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a progressive, multifactorial neurodegenerative disorder that is the main cause of dementia. To date, there are no definitive diagnostic tests that can predict or assess onset and progression of the disease. Blood biomarkers for AD are being sought for many years but their identification remains a challenging task. In this study, we investigated the potential relationship between AD and levels of acyl-peptide hydrolase (APEH) and proteasome in erythrocyte samples of 52 participants (26 AD and 26 cognitively healthy controls). A statistically significant decrease in proteasome and exopeptidase/endopeptidase APEH activities was found in AD samples compared to those of healthy controls. Moreover, in contrast to what was observed for proteasome transcripts, APEH activities reduction in AD patients was unrelated to its gene expression levels, suggesting the occurrence of posttranslational modifications or the expression of endogenous inhibitors that might impair enzyme activity. These preliminary data further support a relationship between the APEH-proteasome system and AD molecular players, providing the first evidence of its potential use as a novel blood-based indicator for the routine detection of AD. [ABSTRACT FROM AUTHOR]

The proteasome is a multienzymatic complex that controls the half-life of the majority of intracellular proteins, including those involved in apoptosis and cell-cycle progression. Recently, proteasome inhibition has been shown to be an effective anticancer strategy, although its downregulation is often accompanied by severe undesired side effects. We previously reported that the inhibition of acylpeptide hydrolase (APEH) by the peptide SsCEI 4 can significantly affect the proteasome activity in A375 melanoma or Caco-2 adenocarcinoma cell lines, thus shedding new light on therapeutic strategies based on downstream regulation of proteasome functions. In this work, we investigated the functional correlation between APEH and proteasome in a panel of cancer cell lines, and evaluated the cell proliferation upon SsCEI 4-treatments. Results revealed that SsCEI 4 triggered a proliferative arrest specifically in osteosarcoma U2OS cells via downregulation of the APEH-proteasome system, with the accumulation of the typical hallmarks of proteasome: NF-κB, p21Waf1, and polyubiquitinylated proteins. We found that the SsCEI 4 anti-proliferative effect involved a senescence-like growth arrest without noticeable cytotoxicity. These findings represent an important step toward understanding the mechanism(s) underlying the APEH-mediated downregulation of proteasome in order to design new molecules able to efficiently regulate the proteasome system for alternative therapeutic strategies. [ABSTRACT FROM AUTHOR]

Protein homoeostasis is a fundamental process allowing the preservation of functional proteins and it has a great impact on the life of the Antarctic organisms. However, the effect of low temperatures on protein turnover is poorly understood and the cold-adaptation of the degradation machinery remains an unresolved issue. As the 26S proteasome represents the main proteolytic system devoted to the controlled degradation of intracellular proteins, the purpose of the present study was to investigate the functions of this complex in the notothenioid Trematomus bernacchii, in order to better understand its role in the physiology of Antarctic fish. To this aim, we purified and characterized the 26S proteasome from T. bernacchii and isolated the cDNAs codifying seven of the 14 subunits belonging to the proteasome 20S core particle. Results provided evidences of the high resistance of the piscine 26S proteasome to oxidative agents and of its ‘uncommon’ ability to efficiently hydrolyse oxidized bovine serum albumin (BSA), suggesting that this enzymatic complex could play a key role in the antioxidant defense systems in fish inhabiting permanently cold marine environments. These unique properties were also reflected by the 3D model analysis, which revealed a higher structural stability of the piscine complex respect to the murine template. Finally, a comparative analysis, performed in a variety of tissues collected from T. bernacchii and the temperate fish Dicentrarchus labrax, showed a lower protein retention in the cold-adapted fish, possibly due to a better efficiency of its degradation machinery. [ABSTRACT FROM AUTHOR]

Acylpeptide hydrolase (APEH) is a ubiquitous cytosolic protease that plays an important role in the detoxification of oxidised proteins. In this work, to further explore the physiological role of this enzyme, two apeh cDNAs were isolated from the Chionodraco hamatus icefish, which lives in the highly oxygenated Antarctic marine environment. The encoded proteins (APEH-1Ch and APEH-2Ch) were characterised in comparison with the uniquely expressed isoform from the temperate fish Dicentrarchus labrax (APEH-1Dl) and the two APEHs from the red-blooded Antarctic fish Trematomus bernacchii (APEH-1Tb and APEH-2Tb). Homology modelling and kinetic characterisation of the APEH isoforms provided new insights into their structure/function properties. APEH-2 isoforms were the only ones capable of hydrolysing oxidised proteins, with APEH-2Ch being more efficient than APEH-2Tb at this specific function. Therefore, this ability of APEH-2 isoforms is the result of an evolutionary adaptation due to the pressure of a richly oxygenated environment. The lack of expression of APEH-2 in the tissues of the temperate fish used as the controls further supported this hypothesis. In addition, analysis of gene expression showed a significant discrepancy between the levels of transcripts and those of proteins, especially for apeh-2 genes, which suggests the presence of post-transcriptional regulation mechanisms, triggered by cold-induced oxidative stress, that produce high basal levels of APEH-2 mRNA as a reserve that is ready to use in case of the accumulation of oxidised proteins. [ABSTRACT FROM AUTHOR]

In this study, we gain insight into the extracellular proteolytic system of Sulfolobus solfataricus grown on proteinaceous substrates, providing further evidence that acidic proteases were specifically produced in response to peptide-rich media. The main proteolytic component was the previously isolated SsMTP (Sulfolobus solfataricus multi-domain thermopsin-like protease), while the less abundant (named SsMTP-1) one was purified, characterized and identified as the sso1175 gene-product. The protein revealed a multi-domain organization shared with the cognate SsMTP with a catalytic domain followed by several tandemly-repeated motifs. Moreover, both enzymes were found spread across the Crenarchaeota phylum and belonging to the thermopsin family, although segregated into diverse phylogenetic clusters. SsMTP-1 showed a 75-kDa molecular mass and was stable in the temperature range 50-90 °C, with optimal activity at 70 °C and pH 2.0. Serine, metallo and aspartic protease inhibitors did not affect the enzyme activity, designating SsMTP-1 as a new member of the pepstatin-insensitive aspartic protease family. The peptide-bond-specificity of SsMTP-1 in the cleavage of the oxidized insulin B chain was uncommon amongst thermopsins, suggesting that it could play a distinct, but cooperative role in the protein degradation machinery. Interestingly, predictions of the transmembrane protein topology of SsMTP and SsMTP-1 strongly suggest a possible contribution in signal-transduction pathways. [ABSTRACT FROM AUTHOR]

Fresh fish are highly perishable, owing mainly to their moisture content, high amount of free amino acids and polyunsaturated fatty acids. Microorganisms and chemical reactions cause the spoilage, leading to loss in quality, human health risks and a market value reduction. Therefore, the fishing industry has always been willing to explore new technologies to increase quality and safety of fish products through a decrease of the microbiological and biochemical damage. In this context, antimicrobial active packaging is one such promising solution to meet consumer demands. The main objective of this study was to evaluate the effects of an active polypropylene-based packaging functionalized with the antimicrobial peptide 1018K6 on microbial growth, physicochemical properties and the sensory attributes of raw salmon fillets. The results showed that application of 1018K6-polypropylene strongly inhibited the microbial growth of both pathogenic and specific spoilage organisms (SSOs) on fish fillets after 7 days. Moreover, salmon also kept its freshness as per volatile chemical spoilage indices (CSIs) during storage. Similar results were obtained on hamburgers of Sarda sarda performing the same analyses. This work provides further evidence that 1018K6-polymers have good potential as antimicrobial packaging for application in the food market to enhance quality and preserve the sensorial properties of fish products. [ABSTRACT FROM AUTHOR]

APEH is a ubiquitous and cytosolic serine protease belonging to the prolyl oligopeptidase (POP) family, playing a critical role in the processes of degradation of proteins through both exo- and endopeptidase events. Endopeptidase activity has been associated with protein oxidation; however, the actual mechanisms have yet to be elucidated. We show that a synthetic fragment of GDF11 spanning the region 48–64 acquires sensitivity to the endopeptidase activity of APEH only when the methionines are transformed into the corresponding sulphoxide derivatives. The data suggest that the presence of sulphoxide-modified methionines is an important prerequisite for the substrates to be processed by APEH and that the residue is crucial for switching the enzyme activity from exo- to endoprotease. The cleavage occurs on residues placed on the C-terminal side of Met(O), with an efficiency depending on the methionine adjacent residues, which thereby may play a crucial role in driving and modulating APEH endoprotease activity. [ABSTRACT FROM AUTHOR]

A novel acylpeptide hydrolase, named APEH-3Ss, was isolated from the hypertermophilic archaeon Sulfolobus solfataricus. APEH is a member of the prolyl oligopeptidase family which catalyzes the removal of acetylated amino acid residues from the N terminus of oligopeptides. The purified enzyme shows a homotrimeric structure, unique among the associate partners of the APEH cluster and, in contrast to the archaeal APEHs which show both exo/endo peptidase activities, it appears to be a "true" aminopeptidase as exemplified by its mammalian counterparts, with which it shares a similar substrate specificity. Furthermore, a comparative study on the regulation of apeh gene expression, revealed a significant but divergent alteration in the expression pattern of apeh-3Ss and apehSs (the gene encoding the previously identified APEHSs from S. solfataricus), which is induced in response to various stressful growth conditions. Hence, both APEH enzymes can be defined as stressregulated proteins which play a complementary role in enabling the survival of S. solfataricus cells under different conditions. These results provide new structural and functional insights into S. solfataricus APEH, offering a possible explanation for the multiplicity of this enzyme in Archaea. [ABSTRACT FROM AUTHOR]

Acylpeptide hydrolase (APEH), one of the four members of the prolyl oligopeptidase class, catalyses the removal of Nacylated amino acids from acetylated peptides and it has been postulated to play a key role in protein degradation machinery. Disruption of protein turnover has been established as an effective strategy to down-regulate the ubiquitinproteasome system (UPS) and as a promising approach in anticancer therapy. Here, we illustrate a new pathway modulating UPS and proteasome activity through inhibition of APEH. To find novel molecules able to down-regulate APEH activity, we screened a set of synthetic peptides, reproducing the reactive-site loop of a known archaeal inhibitor of APEH (SsCEI), and the conjugated linoleic acid (CLA) isomers. A 12-mer SsCEI peptide and the trans10-cis12 isomer of CLA, were identified as specific APEH inhibitors and their effects on cell-based assays were paralleled by a dose-dependent reduction of proteasome activity and the activation of the pro-apoptotic caspase cascade. Moreover, cell treatment with the individual compounds increased the cytoplasm levels of several classic hallmarks of proteasome inhibition, such as NFkappaB, p21, and misfolded or polyubiquitinylated proteins, and additive effects were observed in cells exposed to a combination of both inhibitors without any cytotoxicity. Remarkably, transfection of human bronchial epithelial cells with APEH siRNA, promoted a marked accumulation of a mutant of the cystic fibrosis transmembrane conductance regulator (CFTR), herein used as a model of misfolded protein typically degraded by UPS. Finally, molecular modeling studies, to gain insights into the APEH inhibition by the trans10-cis12 CLA isomer, were performed. Our study supports a previously unrecognized role of APEH as a negative effector of proteasome activity by an unknown mechanism and opens new perspectives for the development of strategies aimed at modulation of cancer progression. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) represent a skilled class of new antibiotics, due to their broad range of activity, rapid killing, and low bacterial resistance. Many efforts have been made to discover AMPs with improved performances, i.e., high antimicrobial activity, low cytotoxicity against human cells, stability against proteolytic degradation, and low costs of production. In the design of new AMPs, several physicochemical features, such as hydrophobicity, net positive charge, propensity to assume amphipathic conformation, and self-assembling properties, must be considered. Starting from the sequence of the dodecapeptide 1018-K6, we designed a new 10-aminoacid peptide, namely RiLK1, which is highly effective against both fungi and Gram-positive and -negative bacteria at low micromolar concentrations without causing human cell cytotoxicity. In order to find the structural reasons explaining the improved performance of RiLK1 versus 1018-K6, a comparative analysis of the two peptides was carried out with a combination of CD, NMR, and fluorescence spectroscopies, while their self-assembling properties were analyzed by optical and atomic force microscopies. Interestingly, the different spectroscopic and microscopic profiles exhibited by the two peptides, including the propensity of RiLK1 to adopt helix arrangements in contrast to 1018-K6, could explain the improved bactericidal, antifungal, and anti-biofilm activities shown by the new peptide against a panel of food pathogens. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are excellent candidates to fight multi-resistant pathogens worldwide and are considered promising bio-preservatives to control microbial spoilage through food processing. To date, designing de novo AMPs with high therapeutic indexes, low-cost synthesis, high resistance, and bioavailability, remains a challenge. In this study, a novel decapeptide, named RiLK1, was rationally designed starting from the sequence of the previously characterized AMP 1018-K6, with the aim of developing short peptides, and promoting higher selectivity over mammalian cells, antibacterial activity, and structural resistance under different salt, pH, and temperature conditions. Interestingly, RiLK1 displayed a broad-spectrum of bactericidal activity against Gram-positive and Gram-negative bacteria, including multidrug resistant clinical isolates of Salmonella species, with Minimal Bactericidal Concentration (MBC) values in low micromolar range, and it was effective even against two fungal pathogens with no evidence of cytotoxicity on human keratinocytes and fibroblasts. Moreover, RiLK1-activated polypropylene films were revealed to efficiently prevent the growth of microbial spoilage, possibly improving the shelf life of fresh food products. These results suggested that de novo designed peptide RiLK1 could be the first candidate for the development of a promising class of decameric and multitask antimicrobial agents to overcome drug-resistance phenomena. [ABSTRACT FROM AUTHOR]

Loranthus europaeus is a well-known and important medicinal plant, with a long history of traditional medicine use. Several studies showed that it contains many bioactive compounds with a wide range of pharmacological effects. In light of these past researches, L. europaeus were chosen to consider its potential antimicrobial action. To this aim, different protocols were performed to selectively extract protein compounds, from L. europaeus yellow fruits, and evaluate the antimicrobial activity against four phytopathogenic fungi (Aspergillus niger, Alternaria spp., Penicillium spp., Botritis cinereus) and a number of foodborne bacterial pathogens (Listeria monocytogenes, Staphylococcus aureus strains, Salmonella Typhimurium and Escherichia coli) by using serial dilutions and colony formation assays. Results evidenced no antifungal activity but a notable bactericidal efficiency of a crude protein extract against two foodborne pathogens, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values between 0.2 and 0.5 mg/mL, being S. aureus strains the most susceptible bacteria. Moreover, a strong bactericidal activity against S. aureus M7 was observed by two partially purified protein fractions of about 600 and 60 kDa molecular mass in native conditions. Therefore, these plant protein extracts could be used as natural alternative preventives to control food poisoning diseases and preserve foodstuff avoiding health hazards of chemically antimicrobial applications. [ABSTRACT FROM AUTHOR]

Food packaging is not only a simple protective barrier, but a real "active" component, which is expected to preserve food quality, safety and shelf-life. Therefore, the materials used for packaging production should show peculiar features and properties. Specifically, antimicrobial packaging has recently gained great attention with respect to both social and economic impacts. In this paper, the results obtained by using a polymer material functionalized by a small synthetic peptide as "active" packaging are reported. The surface of Polyethylene Terephthalate (PET), one of the most commonly used plastic materials in food packaging, was plasma-activated and covalently bio-conjugated to a bactenecin-derivative peptide named 1018K6, previously characterized in terms of antimicrobial and antibiofilm activities. The immobilization of the peptide occurred at a high yield and no release was observed under different environmental conditions. Moreover, preliminary data clearly demonstrated that the "active" packaging was able to significantly reduce the total bacterial count together with yeast and mold spoilage in food-dairy products. Finally, the functionalized-PET polymer showed stronger efficiency in inhibiting biofilm growth, using a Listeria monocytogenes strain isolated from food products. The use of these "active" materials would greatly decrease the risk of pathogen development and increase the shelf-life in the food industry, showing a real potential against a panel of microorganisms upon exposure to fresh and stored products, high chemical stability and re-use possibility. [ABSTRACT FROM AUTHOR]

This study describes the investigation of the efficiency of conjugated linoleic acid (CLA) isomers in reducing cancer cells viability exploring the role of the oxidative stress and acylpeptide hydrolase (APEH)/proteasome mediated pathways on pro-apoptotic activity of the isomer trans10,cis12 (t10,c12)-CLA. The basal activity/expression levels of APEH and proteasome (β-5 subunit) were preliminarily measured in eight cancer cell lines and the functional relationship between these enzymes was clearly demonstrated through their strong positive correlation. t10,c12-CLA efficiently inhibited the activity of APEH and proteasome isoforms in cell-free assays and the negative correlation between cell viability and caspase 3 activity confirmed the pro-apoptotic role of this isomer. Finally, modulatory effects of t10,c12-CLA on cellular redox status (intracellular glutathione, mRNA levels of antioxidant/detoxifying enzymes activated through NF-E2-related factor 2, Nrf2, pathway) and on APEH/β-5 activity/expression levels, were investigated in A375 melanoma cells. Dose- and time-dependent variations of the considered parameters were established and the resulting pro-apoptotic effects were shown to be associated with an alteration of the redox status and a down-regulation of APEH/proteasome pathway. Therefore, our results support the idea that these events are involved in ROS-dependent apoptosis of t10,c12-CLA-treated A375 cells. The combined inhibition, triggered by t10,c12-CLA, via the modulation of APEH/proteasome and Nrf2 pathway for treating melanoma, is suggested as a subject for further in vivo studies. [ABSTRACT FROM AUTHOR]

Abstract Bacteria isolated from different environments can be exploited for biocontrol purposes by the identification of the molecules involved in the antifungal activity. The present study was aimed at investigating antifungal protein compounds purified from a previously identified plant growth promoting bacterium, Pseudomonas protegens N isolated from agricultural land in northern Algeria. Therefore, a novel protein was purified by chromatographic and ultrafiltration steps and its antifungal activity together with growth-inhibition mechanism was evaluated against different fungi by plate-based assays. In addition, stereomicroscopy and transmission electron microscopy (TEM) was performed to explore the inhibition activity of the compound on spore germination processes. The protein, showing a molecular mass of about 100 kDa under native conditions, was revealed to be in the surface-membrane fraction and displayed an efficient activity against a variety of phytopathogenic fungi, being Alternaria the best target towards which it exhibited a marked fungicidal action and inhibition of spore germination. Moreover, the compound was able to significantly decrease fungal infection on tomato fruits producing also morphological aberrations on conidia. The obtained results suggested that the isolated compound could represent a promising agent for eco-friendly management of plant pathogens in agriculture. [ABSTRACT FROM AUTHOR]

Different bacterial groups in irrigation well water are strongly implicated in soil health and plant development. Herein, 48 bacterial strains were isolated from agricultural well water in northern Algeria. Among them, four strains were selected based on their antifungal potential and their ability to express Plant Growth Promoting traits such as Indole Acetic Acid (IAA), hydrolytic enzymes, siderophores etc. The isolates were identified as Pseudomonas sp. (B, D and N strains) and Serratia sp. (C strain) by 16S rRNA gene sequencing. Mycelial growth inhibition against Botrytis cinerea and Aspergillus niger ranged from 60 to 90% for the four strains. Moreover, volatiles compounds emission by the isolates resulted in Plant Growth Inhibition values ranging from 13 to 50%, specifically against B. cinerea . Impressively, the strains’ antifungal activity showed high inducibility as it was obtained only by the filtered supernatants from bacterial cultures previously in contact with the fungus. Finally, a greenhouse assay, carried out to determine the strains’ efficacy in promoting plant growth and protecting seedlings under Pythium aphanidermatum -infected soil, revealed that the strain N markedly enhanced pea germination (+250%) and fresh weight (+43%) and tomato fresh weigh (+10%). The results constitute an attempt for better use of the bacterial functional diversity from irrigation wells in sustainable agriculture. [ABSTRACT FROM AUTHOR]

Staphylococcal food poisoning – caused by certain enterotoxigenic staphylococci – is one of the most common worldwide foodborne diseases. In this context, bacterial biofilms on food processing plan surfaces can represent critical sources of contamination, being more resistant to cleaning and disinfection procedures. Therefore, it is important to prevent and control biofilm formation in food facilities. In the last years, antimicrobial peptides (AMPs) have emerged as promising biofilm contrasting tools. The recently developed AMP, named 1018-K6, revealed a significant bactericidal (MBC 10 μM) and biofilm-preventing efficiency (MBIC 50 μM) against a reference ATCC strain of Listeria monocytogenes and remarkable stability under different environmental conditions. In this work, a kinetic of action of 1018-K6 against two strong biofilm-producing reference strains of Staphylococcus aureus (including a methicillin-resistant S. aureus strain) and a moderate biofilm producer enterotoxigenic S. aureus isolated from cheese, was performed. The peptide showed an impressive rapid mode of action, eradicating established biofilms within few minutes. Bactericidal activity against planktonic cells and inhibition of biofilm formation were also observed. The significant properties of 1018-K6 make it a promising candidate for applications in food-safety and quality control. • 1018-K6 shows a strong and rapid anti-biofilm action against S. aureus strains. • MRSA strain is highly sensible to the antimicrobial action of 1018-K6. • Biofilm of food-isolated SA1 strain was completely eradicated by 1018-K6. • Cell membrane-affecting mode of action of 1018-K6. • A new peptide-based solution for applications in food safety and quality control. [ABSTRACT FROM AUTHOR]