Nanotechnology Formulations for Antibacterial Free Fatty Acids and Monoglycerides

Fatty acid-modified chitosan and nanoencapsulation of essential oils: A snapshot of applications

Chitosan (CS) and its modification with fatty acid (FA) in addition to the nanoencapsulation with essential oils (EOs) have emerged as promising approaches with diverse applications, particularly in food and fruit preservation. This review aims to curate data on the prospects of CS modified with FA as nanostructures, serving as carriers for EOs and its application in the preservation of fruits. A narrative review with no restricted period was used for the general overview of CS and strategies for its modification with FA. Report on CS modified with FA and nanoencapsulation with EO and their applications were appraised. The prospects of CS modified with FA and EO nanoencapsulation in food and fruit preservation were outlined. Most chitosan-fatty acid (CS-FA) studies have found relevance in water, medical and pharmaceutical industries, with few studies on food preservation. CS-FA formulation with EOs shows substantial potential in preserving fruits and will significantly impact the food industry in the future by extending the shelf life of fruits and reducing food waste.

1,3-Dioleoyl-2-palmitoyl-glycerol and 1-oleoyl-2-palmitoyl-3-linoleoyl-glycerol: Structure-function relationship, triacylglycerols preparation, nutrition value

Based on multivariate statistics, this review compared major triacylglycerols (TAGs) in animal milk and human milk fat from China and other countries. Human milk fat differs from animal milk fat in that it has longer acyl chains and higher concentrations of 1,3-dioleoyl-2-palmitoyl-glycerol (O-P-O) and 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (O-P-L). O-P-L is a significant and distinct TAG in human milk fat, particularly in China. 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) is human milk's major triglyceride molecule of O-P-L, accounting for more than 70%. As a result, OPL has piqued the interest of Chinese academics. The synthesis process and nutritional outcomes of OPL have been studied, including changes in gut microbiota, serum lipid composition, improved fatty acid and calcium absorption, and increased total bile acid levels. However, current OPL research is limited. Therefore, this review discussed enzymatic preparation of 1,3-dioleoyl-2-palmitoyl-glycerol (OPO) and OPL and their nutritional and physiological activity to direct future research direction for sn-2 palmitate and OPL.

Current alternative therapies for treating drug-resistant Neisseria gonorrhoeae causing ophthalmia neonatorum

Ophthalmia neonatorum is a microbial contraction, damaging eyesight, occurring largely among neonates. Infants are particularly vulnerable to bacterial infections acquired during birth from infected mothers, especially from Neisseria gonorrhoeae and Chlamydia trachomatis. Over the decades, N. gonorrhoeae is alarmingly developing a resistance to most antibiotics currently prescribed. To counter this challenge, it is imperative to find potent and cost-effective therapeutic agents for prophylaxis and treatment, to which the N. gonorrhoeae cannot easily develop resistance. This review showcases alternate therapies such as antimicrobial-fatty acids, -peptides, -nano-formulations etc., currently evident against N. gonorrhoeae-mediated ophthalmia neonatorum, which remains a major cause of ocular morbidity, blindness and even death among neonates in developing countries.

Polysaccharide-Targeting Lipid Nanoparticles to Kill Gram-Negative Bacteria

The rapid increase and spread of Gram-negative bacteria resistant to many or all existing treatments threaten a return to the preantibiotic era. The presence of bacterial polysaccharides that impede the penetration of many antimicrobials and protect them from the innate immune system contributes to resistance and pathogenicity. No currently approved antibiotics target the polysaccharide regions of microbes. Here, describe monolaurin-based niosomes, the first lipid nanoparticles that can eliminate bacterial polysaccharides from hypervirulent Klebsiella pneumoniae, are described. Their combination with polymyxin B shows no cytotoxicity in vitro and is highly effective in combating K. pneumoniae infection in vivo. Comprehensive mechanistic studies have revealed that antimicrobial activity proceeds via a multimodal mechanism. Initially, lipid nanoparticles disrupt polysaccharides, then outer and inner membranes are destabilized and destroyed by polymyxin B, resulting in synergistic cell lysis. This novel lipidic nanoparticle system shows tremendous promise as a highly effective antimicrobial treatment targeting multidrug-resistant Gram-negative pathogens.

Temperature and pH Stimuli-Responsive System Delivers Location-Specific Antimicrobial Activity with Natural Products

Smart materials with controlled stimuli-responsive functions are at the forefront of technological development. In this work, we present a generic strategy that combines simple components, physicochemical responses, and easy fabrication methods to achieve a dual stimuli-responsive system capable of location-specific antimicrobial cargo delivery. The encapsulated system is fabricated by combining a biocompatible inert polymeric matrix of poly(dimethylsiloxane) (PDMS) and a bioactive cargo of saturated fatty acids. We demonstrate the effectiveness of our approach to deliver antimicrobial activity for the model bacteria Escherichia coli. The system responds to two control variables, temperature and pH, delivering two levels of antimicrobial response under distinct combinations of stimuli: one response toward the planktonic media and another response directly at the surface for sessile bacteria. Spatially resolved Raman spectroscopy alongside thermal and structural material analysis reveals that the system not only exhibits ON/OFF states but can also control relocation and targeting of the active cargo toward either the surface or the liquid media, leading to different ON/OFF states for the planktonic and sessile bacteria. The approach proposed herein is technologically simple and scalable, facing low regulatory barriers within the food and healthcare sectors by using approved components and relying on fundamental chemical processes. Our results also provide a proof-of-concept platform for the design and easy fabrication of delivery systems capable of operating as Boolean logic gates, delivering different responses under different environmental conditions.

M13KO7 bacteriophage enables Potato Virus Y detection

IMPORTANCE

In this study, we confirmed the binding of M13KO7 to Potato virus Y (PVY) using enzyme-linked immunosorbent assay. M13KO7 is a "bald" bacteriophage in which no recombinant antibody is displayed. M13KO7 is easy to propagate by using Escherichia coli, making this method more reasonable in economic perspective. Based on this study, we suggest that M13KO7 detection system has applicability as a novel biological tool for the detection of PVY.

Intestinal Microbiota Community and Blood Fatty Acid Profiles of Albas Cashmere Goats Fed with Flaxseed Oil and Whole Flaxseed

The present study investigated the effects of flaxseed oil or flaxseed grain on the intestinal microbiota and blood fatty acid profiles of Albas cashmere goats. Sixty kid goats were allocated to three treatments and fed for 90 days with a control treatment, comprising a basal diet (CON, total-mixed ration with flaxseed meal), or experimental treatments, comprising a basal diet with added flaxseed oil (LNO) and a basal diet with added heated flaxseed grain (HLS). On day 90, two goats were randomly selected from each pen (eight goats per treatment) for euthanizing; then, five of the eight goats were randomly selected, and we collected their intestinal (duodenum, jejunum, ileum, cecum, and colon) digesta for analysis of the bacteria community. The results indicated that Firmicutes are the most predominant phylum in different segments of the intestinal digesta. Compared with the CON group, the relative abundance of duodenal Firmicutes, jejunal Saccharibacteria, and Verrucomicrobia significantly decreased in the LNO and HLS groups (p < 0.05), but there was no significant difference between the LNO and HLS groups. Compared with the CON and HLS groups, the RA of duodenal and jejunal Proteobacteria remarkably increased in the LNO group (p < 0.05), and there was no significant difference between the CON and HLS groups. Compared with the CON and LNO groups, the RA of Actinobacteria remarkably increased in the small intestine of the HLS group (p < 0.05), but there was no significant difference between the CON and LNO groups in the duodenum and ileum. The results of linear discriminant analysis (LDA) effect size (LEfSe) analysis showed that the HLS group was characterized by a higher RA of the [Eubacterium]_coprostanoligenes_group in the small intestine and the LNO group was represented by a higher RA of the Lachnospiraceae_NK3A20_group in the cecum and colon, while the CON group was represented by a higher RA of Solobacterium, Pseudoramibacter, and Acetitomaculum in the small intestine and a higher RA of norank_o__Bradymonadales, the Prevotellaceae_Ga6A1_group, and Ruminiclostridium_1 in the cecum and colon. In conclusion, the addition of flaxseed oil and grain rich in c18:3n3 to the diet could reduce the microbial diversity of the small intestinal segments and the microbial diversity and richness of the cecum and colon in Albas cashmere goats. And flaxseed grain is more efficient than flaxseed oil in protecting intestinal health and promoting the absorption of c18:3n3.

Multifunctional lipid-based nanoparticles for wound healing and antibacterial applications: A review

Wound healing primarily involves preventing severe infections, accelerating healing, and reducing pain and scarring. Therefore, the multifunctional application of lipid-based nanoparticles (LBNs) has received considerable attention in drug discovery due to their solid or liquid lipid core, which increases their ability to provide prolonged drug release, reduce treatment costs, and improve patient compliance. LBNs have also been used in medical and cosmetic practices and formulated for various products based on skin type, disease conditions, administration product costs, efficiency, stability, and toxicity; therefore, understanding their interaction with biological systems is very important. Therefore, it is necessary to perform an in-depth analysis of the results from a comprehensive characterization process to produce lipid-based drug delivery systems with desired properties. This review will provide detailed information on the different types of LBNs, their formulation methods, characterisation, antimicrobial activity, and application in various wound models (both in vitro and in vivo studies). Also, the clinical and commercial applications of LBNs are summarized.

Recent insights of obesity-induced gut and adipose tissue dysbiosis in type 2 diabetes

An imbalance in microbial homeostasis, referred to as dysbiosis, is critically associated with the progression of obesity-induced metabolic disorders including type 2 diabetes (T2D). Alteration in gut microbial diversity and the abundance of pathogenic bacteria disrupt metabolic homeostasis and potentiate chronic inflammation, due to intestinal leakage or release of a diverse range of microbial metabolites. The obesity-associated shifts in gut microbial diversity worsen the triglyceride and cholesterol level that regulates adipogenesis, lipolysis, and fatty acid oxidation. Moreover, an intricate interaction of the gut-brain axis coupled with the altered microbiome profile and microbiome-derived metabolites disrupt bidirectional communication for instigating insulin resistance. Furthermore, a distinct microbial community within visceral adipose tissue is associated with its dysfunction in obese T2D individuals. The specific bacterial signature was found in the mesenteric adipose tissue of T2D patients. Recently, it has been shown that in Crohn's disease, the gut-derived bacterium Clostridium innocuum translocated to the mesenteric adipose tissue and modulates its function by inducing M2 macrophage polarization, increasing adipogenesis, and promoting microbial surveillance. Considering these facts, modulation of microbiota in the gut and adipose tissue could serve as one of the contemporary approaches to manage T2D by using prebiotics, probiotics, or faecal microbial transplantation. Altogether, this review consolidates the current knowledge on gut and adipose tissue dysbiosis and its role in the development and progression of obesity-induced T2D. It emphasizes the significance of the gut microbiota and its metabolites as well as the alteration of adipose tissue microbiome profile for promoting adipose tissue dysfunction, and identifying novel therapeutic strategies, providing valuable insights and directions for future research and potential clinical interventions.

Saturated long chain fatty acids as possible natural alternative antibacterial agents: Opportunities and challenges

The spread of new strains of antibiotic-resistant pathogenic microorganisms has led to the urgent need to discover and develop new antimicrobial systems. The antibacterial effects of fatty acids have been well-known and recognized since the first experiments of Robert Koch in 1881, and they are now used in diverse fields. Fatty acids can prevent the growth and directly kill bacteria by insertion into their membrane. For that, a sufficient amount of fatty acid molecules has to be solubilized in water to transfer from the aqueous phase to the cell membrane. Due to conflicting results in the literature and lack of standardization methods, it is very difficult to draw clear conclusions on the antibacterial effect of fatty acids. Most of the current studies link fatty acids' effectiveness against bacteria to their chemical structure, notably the alkyl chain length and the presence of double bonds in their chain. Furthermore, the solubility of fatty acids and their critical aggregation concentration is not only related to their structure, but also influenced by medium conditions (pH, temperature, ionic strength, etc.). There is a possibility that the antibacterial activity of saturated long chain fatty acids (LCFA) may be underestimated due to the lack of water solubility and the use of unsuitable methods to assess their antibacterial activity. Thus, enhancing the solubility of these long chain saturated fatty acids is the main goal before examining their antibacterial properties. To increase their water solubility and thereby improve their antibacterial efficacy, novel alternatives may be considered, including the use of organic positively charged counter-ions instead of the conventional sodium and potassium soaps, the formation of catanionic systems, the mixture with co-surfactants, and solubilization in emulsion systems. This review summarizes the latest findings on fatty acids as antibacterial agents, with a focus on long chain saturated fatty acids. Additionally, it highlights the different ways to improve their water solubility, which may be a crucial factor in increasing their antibacterial efficacy. We finish with a discussion on the challenges, strategies and opportunities for the formulation of LCFAs as antibacterial agents.

Dietary Patterns, Gut Microbiota Remodeling, and Cardiometabolic Disease

The cardiovascular and metabolic disorders, collectively known as cardiometabolic disease (CMD), are high morbidity and mortality pathologies associated with lower quality of life and increasing health-care costs. The influence of the gut microbiota (GM) in dictating the interpersonal variability in CMD susceptibility, progression and treatment response is beginning to be deciphered, as is the mutualistic relation established between the GM and diet. In particular, dietary factors emerge as pivotal determinants shaping the architecture and function of resident microorganisms in the human gut. In turn, intestinal microbes influence the absorption, metabolism, and storage of ingested nutrients, with potentially profound effects on host physiology. Herein, we present an updated overview on major effects of dietary components on the GM, highlighting the beneficial and detrimental consequences of diet-microbiota crosstalk in the setting of CMD. We also discuss the promises and challenges of integrating microbiome data in dietary planning aimed at restraining CMD onset and progression with a more personalized nutritional approach.

Polyunsaturated fatty acids-rich dietary lipid prevents high fat diet-induced obesity in mice

Diet is the primary factor affecting host nutrition and metabolism, with excess food intake, especially high-calorie diets, such as high-fat and high-sugar diets, causing an increased risk of obesity and related disorders. Obesity alters the gut microbial composition and reduces microbial diversity and causes changes in specific bacterial taxa. Dietary lipids can alter the gut microbial composition in obese mice. However, the regulation of gut microbiota and host energy homeostasis by different polyunsaturated fatty acids (PUFAs) in dietary lipids remains unknown. Here, we demonstrated that different PUFAs in dietary lipids improved host metabolism in high-fat diet (HFD)-induced obesity in mice. The intake of the different PUFA-enriched dietary lipids improved metabolism in HFD-induced obesity by regulating glucose tolerance and inhibiting colonic inflammation. Moreover, the gut microbial compositions were different among HFD and modified PUFA-enriched HFD-fed mice. Thus, we have identified a new mechanism underlying the function of different PUFAs in dietary lipids in regulating host energy homeostasis in obese conditions. Our findings shed light on the prevention and treatment of metabolic disorders by targeting the gut microbiota.

Time-Restricted Feeding Modifies the Fecal Lipidome and the Gut Microbiota

Time-restricted feeding (TRF) has been identified as an approach to reduce the risk of obesity-related metabolic diseases. We hypothesize that TRF triggers a change in nutrient (e.g., dietary fat) absorption due to shortened feeding times, which subsequently alters the fecal microbiome and lipidome. In this report, three groups of C57BL/6 mice were fed either a control diet with ad libitum feeding (16% energy from fat) (CTRL-AL), a high-fat diet (48% energy from fat) with ad libitum feeding (HF-AL), or a high-fat diet with time-restricted feeding (HF-TRF) for 12 weeks. No changes in microbiota at the phylum level were detected, but eight taxonomic families were altered by either feeding timing or dietary fat content. The HF-AL diet doubled the total fecal fatty acid content of the CTRL-AL diet, while the HF-TRF doubled the total fecal fatty acid content of the HF-AL diet. Primary fecal bile acids were unaffected by diet. Total short-chain fatty acids were reduced by HF-AL, but this effect was diminished by HF-TRF. Each diet produced distinct relationships between the relative abundance of taxa and fecal lipids. The anti-obesogenic effects of TRF in HF diets are partly due to the increase in fat excretion in the feces. Furthermore, fat content and feeding timing differentially affect the fecal microbiota and the relationship between the microbiota and fecal lipids.

Intratumor microbiota as a novel potential prognostic indicator in mesothelioma

Introduction

Despite increased attention on immunotherapy, primarily immune checkpoint blockade, as a therapeutic approach for mesothelioma (MMe), its efficacy and tolerability remain questioned. One potential explanation for different responses to immunotherapy is the gut and intratumor microbiota; however, these remain an underexplored facet of MMe. This article highlights the cancer intratumor microbiota as a novel potential prognostic indicator in MMe.

Methods

TCGA data on 86 MMe patients from cBioPortal underwent bespoke analysis. Median overall survival was used to divide patients into “Low Survivors” and “High Survivors”. Comparison of these groups generated Kaplan-Meier survival analysis, differentially expressed genes (DEGs), and identification of differentially abundant microbiome signatures. Decontamination analysis refined the list of signatures, which were validated as an independent prognostic indicator through multiple linear regression modelling and Cox proportional hazards modelling. Finally, functional annotation analysis on the list of DEGs was performed to link the data together.

Results

107 genera signatures were significantly associated with patient survival (positively or negatively), whilst clinical characteristic comparison between the two groups demonstrated that epithelioid histology was more common in “High Survivors” versus biphasic in “Low Survivors”. Of the 107 genera, 27 had published articles related to cancer, whilst only one (Klebsiella) had MMe-related published articles. Functional annotation analysis of the DEGs between the two groups highlighted fatty acid metabolism as the most enriched term in “High Survivors”, whilst for “Low Survivors” the enriched terms primarily related to cell cycle/division. Linking these ideas and findings together is that the microbiome influences, and is influenced by, lipid metabolism. Finally, to validate the independent prognostic value of the microbiome, multiple linear regression modelling as well as Cox proportional hazards modelling were employed, with both approaches demonstrating that the microbiome was a better prognostic indicator than patient age or stage of the cancer.

Discussion

The findings presented herein, alongside the very limited literature from scoping searches to validate the genera, highlight the microbiome and microbiota as a potentially rich source of fundamental analysis and prognostic value. Further in vitro studies are needed to elucidate the molecular mechanisms and functional links that may lead to altered survival.

The gut microbiota-artery axis: A bridge between dietary lipids and atherosclerosis?

Atherosclerotic cardiovascular disease is one of the major leading global causes of death. Growing evidence has demonstrated that gut microbiota (GM) and its metabolites play a pivotal role in the onset and progression of atherosclerosis (AS), now known as GM-artery axis. There are interactions between dietary lipids and GM, which ultimately affect GM and its metabolites. Given these two aspects, the GM-artery axis may play a mediating role between dietary lipids and AS. Diets rich in saturated fatty acids (SFAs), omega-6 polyunsaturated fatty acids (n-6 PUFAs), industrial trans fatty acids (TFAs), and cholesterol can increase the levels of atherogenic microbes and metabolites, whereas monounsaturated fatty acids (MUFAs), ruminant TFAs, and phytosterols (PS) can increase the levels of antiatherogenic microbes and metabolites. Actually, dietary phosphatidylcholine (PC), sphingomyelin (SM), and omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been demonstrated to affect AS via the GM-artery axis. Therefore, that GM-artery axis acts as a communication bridge between dietary lipids and AS. Herein, we will describe the molecular mechanism of GM-artery axis in AS and discuss the complex interactions between dietary lipids and GM. In particular, we will highlight the evidence and potential mechanisms of dietary lipids affecting AS via GM-artery axis.

Sustainable bio-based antimicrobials derived from fatty acids: Synthesis, safety, and efficacy

Some conventional sanitizers and antibiotics used in food industry may be of concerns due to generation of toxic byproducts, impact on the environment, and the emergence of antibiotic resistance bacteria. Bio-based antimicrobials can be an alternative to conventional sanitizers since they are produced from renewable resources, and the bacterial resistance to these compounds is of less concern than those of currently used antibiotics. Among the bio-based antimicrobial compounds, those produced via either fermentation or chemical synthesis by covalently or electrovalently attaching specific moieties to the fatty acid have drawn attention in recent years. Disaccharide, arginine, vitamin B1, and phenolics are linked to fatty acids resulting in the production of sophorolipid, lauric arginate ethyl ester, thiamin dilauryl sulfate, and phenolic branched-chain fatty acid, respectively, all of which are reported to exhibit antimicrobial activity by targeting the cell membrane of the bacteria. Also, studies that applied these compounds as food preservatives by combining them with other compounds or treatments have been reviewed regarding extending the shelf life and inactivating foodborne pathogens of foods and food products. In addition, the phenolic branched-chain fatty acids, which are relatively new compounds compared to the others, are highlighted in this review.

Cationic Liposomes with Different Lipid Ratios: Antibacterial Activity, Antibacterial Mechanism, and Cytotoxicity Evaluations

Due to their strong bacterial binding and bacterial toxicity, cationic liposomes have been utilized as effective antibacterial materials in many studies. However, few researchers have systematically compared their antibacterial activity with their mammalian cell cytotoxicity or have deeply explored their antibacterial and cytotoxicity mechanisms. Here, we prepared a series of cationic liposomes (termed CLs) using dimethyldioctadecylammonium chloride (DODAC) and lecithin at different molar ratios. CLs have the ability to effectively bind with Gram-positive and Gram-negative bacteria through electrostatic and hydrophobic interactions. Further, the CLs with high molar ratios of DODAC (30 and 40 mol%) can disrupt the bacterial wall/membrane, efficiently inducing the production of reactive oxygen species (ROS). More importantly, we carefully compared the antibacterial activity and the mammalian cell cytotoxicity of various CLs differing in DODAC contents and liposomal concentrations and revealed that, whether they are bacterial or mammalian cells, an increasing DODAC content in CLs can lead to an elevated cytotoxicity level. Further, there exists a critical DODAC contents (>20 mol%) in CLs to endow them with effective antibacterial ability. However, the variation in the DODAC content and liposomal concentration of CLs has different degrees of influence on the antibacterial activity or cytotoxicity. For example, CLs at high DODAC content (i.e., CL0.3 and CL0.4) could effectively kill both types of bacterial cells but only cause negligible toxicity to mammalian cells. We believe that a systematic comparison between the antibacterial activity and the cytotoxicity of CLs with different DODAC contents will provide an important reference for the potential clinical applications of cationic liposomes.

Influence of silver ion release on the inactivation of antibiotic resistant bacteria using light-activated silver nanoparticles

The widespread increase in antibiotic resistance (AR), in an extensive range of microorganisms, demands the development of alternative antimicrobials with novel non-specific low-mutation bacterial targets. Silver nanoparticles (AgNPs) and photosensitizers (PSs) are promising antimicrobial agents with broad-spectrum activity and low tendency for antimicrobial resistance development. Herein, we investigated the light-mediated oxidation of AgNPs for accelerated release of Ag⁺ in the antibacterial synergy of PS-AgNP conjugates using protoporphyrin IX (PpIX) as a PS. Also, the influence of polyethyleneimine (PEI) coated AgNPs in promoting antibacterial activity was examined. We synthesized, characterized and tested the antimicrobial effect of three nanoparticles: AgNPs, PpIX-AgNPs, and PEI-PpIX-AgNPs against a methicillin-resistant Staphylococcus aureus strain (MRSA) and a wild-type multidrug resistant (MDR) E. coli. PpIX-AgNPs were the most effective material achieving >7 log inactivation of MRSA and MDR E. coli. The order of bacterial log inactivation was PpIX-AgNPs > PEI-PpIX-AgNPs > AgNPs. This order correlates with the trend of Ag⁺ concentration released by the NPs (PpIX-AgNPs > PEI-PpIX-AgNPs > AgNPs). Our study confirms a synergistic effect between PpIX and AgNPs in the inactivation of AR pathogens with about 10-fold increase in inactivation of ARB relative to AgNPs only. The concentration of Ag⁺ released from NPs determined the log inactivation of MRSA and MDR E. coli more than either the phototoxic effect or the electrostatic interaction promoted by surface charge of nanoparticles with bacteria cells. All NPs showed negligible cytotoxicity to mammalian cells at the bacterial inhibitory concentration after 24 h exposure. These observations confirm the crucial role of optimized Ag⁺ release for enhanced performance of AgNP-based antimicrobials against AR pathogens.

Antiviral activity of nano-monocaprin against Phi6 as a surrogate for SARS-CoV-2

The COVID-19 pandemic involving SARS-CoV-2 has raised interest in using antimicrobial lipid formulations to inhibit viral entry into their host cells or to inactivate them. Lipids are a part of the innate defense mechanism against pathogens. Here, we evaluated the use of nano-monocaprin (NMC) in inhibiting enveloped (phi6) and unenveloped (MS2) bacteriophages. NMC was prepared using the sonochemistry technique. Size and morphology analysis revealed the formation of ~ 8.4 ± 0.2-nm NMC as measured by dynamic light scattering. We compared the antiviral activity of NMC with molecular monocaprin (MMC) at 0.5 mM and 2 mM concentrations against phi6, which we used as a surrogate for SARS-CoV-2. The synthesized NMC exhibited 50% higher antiviral activity against phi6 than MMC at pH 7 using plaque assay. NMC inactivated phi6 stronger at pH 4 than at pH 7. To determine if NMC is toxic to mammalian cells, we used MTS assay to assess its IC₅₀ for HPDE and HeLa cell lines, which were ~ 203 and 221 µM, respectively. NMC may be used for prophylactic application either as a drop or spray since many viruses enter the human body through the mucosal lining of the nose, eyes, and lungs.

Nanoarchitectonics-based model membrane platforms for probing membrane-disruptive interactions of odd-chain antimicrobial lipids

The use of nanoscience tools to investigate how antimicrobial lipids disrupt phospholipid membranes has greatly advanced molecular-level biophysical understanding and opened the door to new application possibilities. Until now, relevant studies have focused on even-chain antimicrobial lipids while there remains an outstanding need to investigate the membrane-disruptive properties of odd-chain antimicrobial lipids that are known to be highly biologically active. Herein, using the quartz crystal microbalance-dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS) techniques, we investigated how an 11-carbon, saturated fatty acid and its corresponding monoglyceride-termed undecanoic acid and monoundecanoin, respectively-disrupt membrane-mimicking phospholipid bilayers with different nanoarchitectures. QCM-D tracking revealed that undecanoic acid and monoundecanoin caused membrane tubulation and budding from supported lipid bilayers, respectively, and were only active above their experimentally determined critical micelle concentration (CMC) values. Monoundecanoin was more potent due to a lower CMC and electrochemical impedance spectroscopy (EIS) characterization demonstrated that monoundecanoin caused irreversible membrane disruption of a tethered lipid bilayer platform at sufficiently high compound concentrations, whereas undecanoic acid only induced transient membrane disruption. This integrated biophysical approach also led us to identify that the tested 11-carbon antimicrobial lipids cause more extensive membrane disruption than their respective 12-carbon analogues at 2 × CMC, which suggests that they could be promising molecular components within next-generation antimicrobial nanomedicine strategies.

Recent Advances in the Development of Lipid-, Metal-, Carbon-, and Polymer-Based Nanomaterials for Antibacterial Applications

Infections caused by multidrug-resistant (MDR) bacteria are becoming a serious threat to public health worldwide. With an ever-reducing pipeline of last-resort drugs further complicating the current dire situation arising due to antibiotic resistance, there has never been a greater urgency to attempt to discover potential new antibiotics. The use of nanotechnology, encompassing a broad range of organic and inorganic nanomaterials, offers promising solutions. Organic nanomaterials, including lipid-, polymer-, and carbon-based nanomaterials, have inherent antibacterial activity or can act as nanocarriers in delivering antibacterial agents. Nanocarriers, owing to the protection and enhanced bioavailability of the encapsulated drugs, have the ability to enable an increased concentration of a drug to be delivered to an infected site and reduce the associated toxicity elsewhere. On the other hand, inorganic metal-based nanomaterials exhibit multivalent antibacterial mechanisms that combat MDR bacteria effectively and reduce the occurrence of bacterial resistance. These nanomaterials have great potential for the prevention and treatment of MDR bacterial infection. Recent advances in the field of nanotechnology are enabling researchers to utilize nanomaterial building blocks in intriguing ways to create multi-functional nanocomposite materials. These nanocomposite materials, formed by lipid-, polymer-, carbon-, and metal-based nanomaterial building blocks, have opened a new avenue for researchers due to the unprecedented physiochemical properties and enhanced antibacterial activities being observed when compared to their mono-constituent parts. This review covers the latest advances of nanotechnologies used in the design and development of nano- and nanocomposite materials to fight MDR bacteria with different purposes. Our aim is to discuss and summarize these recently established nanomaterials and the respective nanocomposites, their current application, and challenges for use in applications treating MDR bacteria. In addition, we discuss the prospects for antimicrobial nanomaterials and look forward to further develop these materials, emphasizing their potential for clinical translation.

Effect of Atkins versus a low-fat diet on gut microbiota, and cardiometabolic markers in obese women following an energy-restricted diet: Randomized, crossover trial

BACKGROUND AND AIMS

There is controversy about effects of the Atkins diet on cardiometabolic markers in previous studies. No study compared effects of Atkins versus a low-fat diet on gut microbiota in obese women during a weight-loss program up to date.

METHODS AND RESULTS

A 6-week, randomized, crossover trial was conducted. Twenty-four healthy women with obesity (BMI≥30 kg/m²) were randomly assigned to receive the Atkins (55%, 25%, and 20% of total daily calories from fat, protein, and carbohydrates), or low-fat (20%, 15%, and 65% of total daily calories from fat, protein, and carbohydrates) diets while following a weight-loss program. Vegetable oils were used as the main source of dietary fat. Dietary groups were switched after two weeks of washout period with a weight maintenance low-fat diet. The effects of the two diets did not differ for the most endpoints. However, Gut Actinobacteria residency and serum total antioxidant capacity significantly increased in the Akins diet group compared with the low-fat one (p = 0.02 and p = 0.04). Adjusting for all parameters, gut Actinobacteria residency 1.48- and 2.5-folds decreased the serum LDL.C/HDL.C ratio and non-HDL.C levels (95%CI: 3.1, -0.22; p = 0.03 and -0.07, -0.002; p = 0.04), respectively. Decrease in gut Proteobacteria residency showed a significant reduction in serum total oxidant status (95%CI: 7.4, -0.07; p = 0.04).

CONCLUSIONS

The Atkins diet, based on vegetable oils, alters gut microbiota composition, atherogenic and antioxidant parameters.

REGISTRATION NUMBER FOR CLINICAL TRIAL

IRCT20200929048876N3.

Targeting and Killing the Ever-Challenging Ulcer Bug

TreatingHelicobacter pylori(H. pylori) infections has been a never-ending challenge, which has contributed to the high incidence of gastric cancer. The antibiotics commonly used are not reaching the infection site in its active state and in a concentration high enough to effectively kill the bacteria. In this context, amoxicillin-loaded lipid nanoparticles with carefully chosen materials were developed, namely dioleoylphosphatidylethanolamine (DOPE) as a targeting agent and Tween®80 and linolenic acid as antimicrobial agents. This work shows the ability of these nanoparticles in (i) targeting the bacteria (imaging flow cytometry) and inhibiting their adhesion to MKN-74 cells (bacteria-gastric cells adhesion model); (ii) killing the bacteria even as an antibiotic-free strategy (time-kill kineticstudies, scanning electron microscopy, and bacterial membrane permeability studies); (iii)overcoming gastrointestinal features using a newly developedin vitroinfection model that includes both physical (epithelial cells and mucus) and the chemical (acid medium) barriers; and in (iv) being incorporated in a floating system that can increase the retention time at the stomach. Overall, this work presents an effective nanosystem to deal with the ulcer-bug. Besides, it also provides two innovative tools transferable to other fields-anin vitroinfection model and a floating system to incorporate nanoparticles.

Zein-Based Films Containing Monolaurin/Eugenol or Essential Oils with Potential for Bioactive Packaging Application

Zein is renewable plant protein with valuable film-forming properties that can be used as a packaging material. It is known that the addition of natural cross-linkers can enhance a film’s tensile properties. In this study, we aimed to prepare antimicrobial zein-based films enriched with monolaurin, eugenol, oregano, and thyme essential oil. Films were prepared using the solvent casting technique from ethanol solution. Their physicochemical properties were investigated using structural, morphological, and thermal techniques. Polar and dispersive components were analyzed using two models to evaluate the effects on the surface free energy values. The antimicrobial activity was proven using a disk diffusion method and the suppression of bacterial growth was confirmed via a growth kinetics study with the Gompertz function. The films’ morphological characteristics led to systems with uniform distribution of essential oils or eugenol droplets combined with a flat-plated structure of monolaurin. A unique combination of polyphenolic eugenol and amphiphilic monoglyceride provided highly stretchable films with enhanced barrier properties and efficiency against Gram-positive and Gram-negative bacteria, yeasts, and molds. The prepared zein-based films with tunable surface properties represent an alternative to non-renewable resources with a potential application as active packaging materials.

Reuse of Textile Waste to Production of the Fibrous Antibacterial Membrane with Filtration Potential

Wasted synthetic fabrics are a type of textile waste source; the reuse of them brings environmental protection and turns waste into a valuable material. In this work, the used nylon (polyamide) stockings were transmuted into a fine fibrous membrane via an electrospinning process. In addition, the safety antibacterial agent, monoacylglycerol (MAG), was incorporated into a recycled fibrous membrane. The results revealed that the neat, recycled polyamide (rPA) fibers with a hydrophobic surface could be converted into hydrophilic fibers by blending various amounts of MAG with rPA solution prior to electrospinning. The filtration efficiency and air/water vapor permeability of the two types of produced membranes, neat rPA, and rPA/MAG, were tested. Their filtration efficiency (E100) was more than 92% and 96%, respectively. The membranes were classified according to Standard EN1822, and therefore, the membranes rPA and rPA/MAG were assigned to the classes E10 and E11, respectively. The air permeability was not affected by the addition of MAG, and water vapor permeability was slightly enhanced. Based on the obtained data, prepared rPA/MAG fibrous membranes can be evaluated as antifouling against both tested bacterial strains and antimicrobial against S. aureus.

Point of care diagnosis of plant virus: Current trends and prospects

Plant viral diseases accounts for major global economic losses in modern-day agriculture. Plant viral disease management is the primary challenge for both farmers and researchers. Detection and identification of plant viruses are of paramount importance for successful management of a viral disease. Recent advancements in molecular biology have contributed to significant progress in the development of new, sensitive, and effective diagnostic methods. However, most techniques are neither time/cost-effective nor user-friendly and require sophisticated labs. Hence, the past few decades of agricultural research have mainly focused on developing farmer-friendly, point-of-care diagnostic tools that provide high-sensitive rapid diagnosis. The current trend in plant virus diagnostic tools is cheaper, easy-to-use portable devices with no compromise on sensitivity and reproducibility.

Lipid Nanoparticle Technology for Delivering Biologically Active Fatty Acids and Monoglycerides

There is enormous interest in utilizing biologically active fatty acids and monoglycerides to treat phospholipid membrane-related medical diseases, especially with the global health importance of membrane-enveloped viruses and bacteria. However, it is difficult to practically deliver lipophilic fatty acids and monoglycerides for therapeutic applications, which has led to the emergence of lipid nanoparticle platforms that support molecular encapsulation and functional presentation. Herein, we introduce various classes of lipid nanoparticle technology and critically examine the latest progress in utilizing lipid nanoparticles to deliver fatty acids and monoglycerides in order to treat medical diseases related to infectious pathogens, cancer, and inflammation. Particular emphasis is placed on understanding how nanoparticle structure is related to biological function in terms of mechanism, potency, selectivity, and targeting. We also discuss translational opportunities and regulatory needs for utilizing lipid nanoparticles to deliver fatty acids and monoglycerides, including unmet clinical opportunities.

Cyclodextrin-based Pickering emulsions: functional properties and drug delivery applications

Cyclodextrins (CDs) are biocompatible, cyclic oligosaccharides that are widely used in various industrial applications and have intriguing interfacial science properties. While CD molecules typically have low surface activity, they are capable of stabilizing emulsions by inclusion complexation of oil-phase components at the oil/water interface, which results in Pickering emulsion formation. Such surfactant-free formulations have gained considerable attention in recent years, owing to their enhanced physical stability, improved tolerability, and superior environmental compatibility compared to conventional, surfactant-based emulsions. In this review, we critically describe the latest insights into the molecular mechanisms involved in CD stabilization of Pickering emulsions, including covering practical aspects such as methods to prepare CD-based Pickering emulsions, lipid encapsulation, and relevant stability issues. In addition, the rheological and textural features of CD-based Pickering emulsions are discussed and particular attention is focused on promising examples for drug delivery, cosmetic, and nutraceutical applications. The functionality of currently developed CD-based Pickering emulsions is also summarised, including examples such as antifungal uses, and we close by discussing emerging possibilities to utilize the molecular encapsulation of CD-based emulsions for translational medicine applications in the antiviral and antibacterial spaces.

Nutrigenomics of Dietary Lipids

Dietary lipids have a major role in nutrition, not only for their fuel value, but also as essential and bioactive nutrients. This narrative review aims to describe the current evidence on nutrigenomic effects of dietary lipids. Firstly, the different chemical and biological properties of fatty acids contained both in plant- and animal-based food are illustrated. A description of lipid bioavailability, bioaccessibility, and lipotoxicity is provided, together with an overview of the modulatory role of lipids as pro- or anti-inflammatory agents. Current findings concerning the metabolic impact of lipids on gene expression, epigenome, and gut microbiome in animal and human studies are summarized. Finally, the effect of the individual’s genetic make-up on lipid metabolism is described. The main goal is to provide an overview about the interaction between dietary lipids and the genome, by identifying and discussing recent scientific evidence, recognizing strengths and weaknesses, to address future investigations and fill the gaps in the current knowledge on metabolic impact of dietary fats on health.

Stopping Membrane-Enveloped Viruses with Nanotechnology Strategies: Toward Antiviral Drug Development and Pandemic Preparedness

Membrane-enveloped viruses are a leading cause of viral epidemics, and there is an outstanding need to develop broad-spectrum antiviral strategies to treat and prevent enveloped virus infections. In this review, we critically discuss why the lipid membrane surrounding enveloped virus particles is a promising antiviral target and cover the latest progress in nanotechnology research to design and evaluate membrane-targeting virus inhibition strategies. These efforts span diverse topics such as nanomaterials, self-assembly, biosensors, nanomedicine, drug delivery, and medical devices and have excellent potential to support the development of next-generation antiviral drug candidates and technologies. Application examples in the areas of human medicine and agricultural biosecurity are also presented. Looking forward, research in this direction is poised to strengthen capabilities for virus pandemic preparedness and demonstrates how nanotechnology strategies can help to solve global health challenges related to infectious diseases.

Chitosan nanoparticles based on their derivatives as antioxidant and antibacterial additives for active bioplastic packaging

Chitosan nanoparticles (CSNPs) based on their different derivatives were proposed as antioxidant and antimicrobial additives for active bioplastic packaging. Chitosan was modified with polyethylene glycol methyl ether methacrylate (PEGMA), stearyl methacrylate (SMA) and deoxycholic acid (DC) using radiation-induced graft polymerization and chemical conjugation. The modified CSNPs-g-pPEGMA, CSNPs-g-pSMA and CSNPs-DC self-assembled into nanoparticles with the size in the range of 25-60 nm. The CSNPs-DC derivative has superior antioxidant activity and the CSNPs-g-pSMA derivative exhibited outstanding antibacterial activity against growth of E.coli (95.33 %). All modified CSNPs showed their capacities to inhibit S.aureus bacterial growth (>98 %). PLA packaging films containing CSNPs-g-pSMA inhibited the growth of natural microorganism on bread slices. Different chemical functions of the CSNPs derivatives provided different gas permeability and mechanical properties of the PLA films. The CSNPs derivatives would be promising antioxidant and antimicrobial additives for bioplastics to be further used as bio-based active food packaging.

Inhibition of African swine fever virus in liquid and feed by medium-chain fatty acids and glycerol monolaurate

BACKGROUND

The ongoing African swine fever virus (ASFv) epidemic has had a major impact on pig production globally and biosecurity efforts to curb ASFv infectivity and transmission are a high priority. It has been recently identified that feed and feed ingredients, along with drinking water, can serve as transmission vehicles and might facilitate transboundary spread of ASFv. Thus, it is important to test the antiviral activity of regulatory compatible, antiviral feed additives that might inhibit ASFv infectivity in feed. One promising group of feed additive candidates includes medium-chain fatty acids (MCFA) and monoglyceride derivatives, which are known to disrupt the lipid membrane surrounding certain enveloped viruses and bacteria.

RESULTS

The antiviral activities of selected MCFA, namely caprylic, capric, and lauric acids, and a related monoglyceride, glycerol monolaurate (GML), to inhibit ASFv in liquid and feed conditions were investigated and suitable compounds and inclusion rates were identified that might be useful for mitigating ASFv in feed environments. Antiviral assays showed that all tested MCFA and GML inhibit ASFv. GML was more potent than MCFA because it worked at a lower concentration and inhibited ASFv due to direct virucidal activity along with one or more other antiviral mechanisms. Dose-dependent feed experiments further showed that sufficiently high GML doses can significantly reduce ASFv infectivity in feed in a linear manner in periods as short as 30 min, as determined by infectious viral titer measurements. Enzyme-linked immunosorbent assay (ELISA) experiments revealed that GML treatment also hinders antibody recognition of the membrane-associated ASFv p72 structural protein, which likely relates to protein conformational changes arising from viral membrane disruption.

CONCLUSION

Together, the findings in this study indicate that MCFA and GML inhibit ASFv in liquid conditions and that GML is also able to reduce ASFv infectivity in feed, which may help to curb disease transmission.

A novel antiviral formulation inhibits a range of enveloped viruses

Some free fatty acids derived from milk and vegetable oils are known to have potent antiviral and antibacterial properties. However, therapeutic applications of short- to medium-chain fatty acids are limited by physical characteristics such as immiscibility in aqueous solutions. We evaluated a novel proprietary formulation based on an emulsion of short-chain caprylic acid, ViroSAL, for its ability to inhibit a range of viral infections in vitro and in vivo. In vitro, ViroSAL inhibited the enveloped viruses Epstein-Barr, measles, herpes simplex, Zika and orf parapoxvirus, together with Ebola, Lassa, vesicular stomatitis and severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) pseudoviruses, in a concentration- and time-dependent manner. Evaluation of the components of ViroSAL revealed that caprylic acid was the main antiviral component; however, the ViroSAL formulation significantly inhibited viral entry compared with caprylic acid alone. In vivo, ViroSAL significantly inhibited Zika and Semliki Forest virus replication in mice following the inoculation of these viruses into mosquito bite sites. In agreement with studies investigating other free fatty acids, ViroSAL had no effect on norovirus, a non-enveloped virus, indicating that its mechanism of action may be surfactant disruption of the viral envelope. We have identified a novel antiviral formulation that is of great interest for the prevention and/or treatment of a broad range of enveloped viruses, particularly those of the skin and mucosal surfaces.

In vitro and in vivo efficacy of methyl oleate and palmitic acid against ESBL producing MDR Escherichia coli and Klebsiella pneumoniae

PURPOSE

Antibiotic resistance is a huge problem that stays to challenge the healthcare sector in a large part of the world in both developing and developed countries. The spread of multi drug resistant (MDR) bacteria in hospital and community settings remains a widely uncertain problem and a heavy burden to health services.

METHODS

This study unveils the in vitro and in vivo anti-ESBL potential of Methyl oleate (MO) and Palmitic acid (PA) against ESBL producing MDR bacterial pathogens such as Escherichia coli and Klebsiella pneumoniae. Microscopic observations unveiled the anti-ESBL efficacy of test compounds. MTT assay, in vivo anti-infective efficiency of MO and PA was tested with different concentrations.

RESULTS

The pure compounds of MO and PA from Oxynema thaianum demonstrated high inhibitory activity in MIC and MBC assays against MDR E. coli and K. pneumoniae. Moreover, the anti-ESBL potential of MO and PA was validated through light, confocal laser scanning and scanning electron microscopic analyses. The IC₅₀ values of MO and PA against A549 cells was recorded as 625 μg mL^-1 and 514 μg mL^-1, respectively. In Artemia nauplii cytotoxicity assay, the LC₅₀ value of MO and PA were recorded as 53.33 μg mL^-1 and 50 μg mL^-1 respectively. The 96 h lethal concentrations obtained for Lobeo rohita treated with different concentrations of Methyl oleate and Palmitic acid. The LC₅₀ for MO and PA was 50 mg L^-1 and 100 mg L^-1, respectively.

CONCLUSION

Therefore the study concluded that the promising effects of MO and PA can be used as an alternative biological agent which could be positively explored to treat ESBL producing MDR pathogens.

Novel Polyvinyl Butyral/Monoacylglycerol Nanofibrous Membrane with Antifouling Activity

Monoacylglycerols (MAGs) have proven of great interest to the foodstuffs industry due to the promising antibacterial activity they show for controlling microbial contamination. Prior to this paper, this antibacterial agent had not been incorporated in a nanofibrous membrane. This study details convenient fabrication of nanofibrous membranes based on polyvinyl butyral (PVB) containing various concentrations of monocaprin (MAG 10) by an electrospinning process. Increasing the concentration of MAG 10 caused differences to appear in the shape of the nanofibers, in addition to which the level of wettability was heightened. Besides exhibiting antibacterial properties, the functional membranes demonstrated especially good antifouling activity. The novel and efficient nanofibrous membranes described have the potential to find eventual application in medical or environmental fields.

Medium-chain fatty acids and monoglycerides as feed additives for pig production: towards gut health improvement and feed pathogen mitigation

Ongoing challenges in the swine industry, such as reduced access to antibiotics and virus outbreaks (e.g., porcine epidemic diarrhea virus, African swine fever virus), have prompted calls for innovative feed additives to support pig production. Medium-chain fatty acids (MCFAs) and monoglycerides have emerged as a potential option due to key molecular features and versatile functions, including inhibitory activity against viral and bacterial pathogens. In this review, we summarize recent studies examining the potential of MCFAs and monoglycerides as feed additives to improve pig gut health and to mitigate feed pathogens. The molecular properties and biological functions of MCFAs and monoglycerides are first introduced along with an overview of intervention needs at different stages of pig production. The latest progress in testing MCFAs and monoglycerides as feed additives in pig diets is then presented, and their effects on a wide range of production issues, such as growth performance, pathogenic infections, and gut health, are covered. The utilization of MCFAs and monoglycerides together with other feed additives such as organic acids and probiotics is also described, along with advances in molecular encapsulation and delivery strategies. Finally, we discuss how MCFAs and monoglycerides demonstrate potential for feed pathogen mitigation to curb disease transmission. Looking forward, we envision that MCFAs and monoglycerides may become an important class of feed additives in pig production for gut health improvement and feed pathogen mitigation.

Polyvinyl Alcohol/Chitosan/Polyhexamethylene Biguanide Phase Separation System: A Potential Topical Antibacterial Formulation with Enhanced Antimicrobial Effect

An aqueous polyvinyl alcohol (PVA)/chitosan (CHT)/polyhexamethylene biguanide (PHMB) blends (PVA/CHT/PHMB blends) has been developed as a potential low dose topical antibacterial formulation with enhanced antimicrobial effect. The preparation of PVA/CHT/PHMB blends was quite facilely, with just dissolved PVA, CHT, PHMB in water in order. There was the aggregates with 100 nm size around induced by phase separation in the blends and an aqueous two-phase system (ATPS) formed, as non-ionic polymer PVA formed a continuous phase and cationic polymer CHT and PHMB formed dispersed phases. The minimum inhibitory concentration (MIC) of PHMB in the PVA/CHT/PHMB blends was 0.5μg/mL, which was four times lower than the MIC of PHMB individually. A phase separation increased zeta potential mechanism was proposed to explain the enhanced antibacterial activities. In addition, the blends could easily form film on the skin surface with good water vapor permeability and be used as a liquid bandage to accelerate the scratch wound healing process of nude mouse. These findings provide experimental evidence that the PHMB-functionalized blends could be further explored as low-dose topical antibacterial formulations, and the nano-sized phase separation strategy could be used to design novel low-dose topical antibacterial formulations with an enhanced antimicrobial effect.

Spatial repellency, antifeedant activity and toxicity of three medium chain fatty acids and their methyl esters of coconut fatty acid against stable flies

BACKGROUND

Stable flies are one of the most detrimental arthropod pests to livestock. With changing climates and agronomic practices, they expand their roles as pests and disease vectors as well. Their painful bites reduce livestock productivity, annoy companion animals, and interfere with human recreational activities. Current management technologies are unable to effectively control stable flies. The present study reports new results concerning the contact, spatial repellency, and toxicity of a bio-based product, coconut fatty acid and their methyl ester derivatives of free fatty acids of C_8:0 , C_10:0 and C_12:0 to stable flies.

RESULTS

Three medium chain fatty acid methyl esters (C_8:0 , C_10:0 and C_12:0 ) showed strong antifeedant activity against stable flies and their strengths were dose-dependent. Only the C_8:0 acid, C_8:0 - and C_10:0 methyl esters elicited significant antennal responses. Laboratory single cage olfactometer bioassays revealed that coconut fatty acid and C_8:0 methyl ester displayed active spatial repellency. All three methyl esters showed strong toxicity against stable flies.

CONCLUSION

Antifeedant activity is the main method through which coconut fatty acid deters stable fly blood-feeding. The C_8:0 , C_10:0 and C_12:0 methyl esters act not only as strong antifeedants, but also possess strong toxicity against stable fly adults. Limited spatial repellency was observed from coconut fatty acid and C_8:0 methyl ester. © 2019 Society of Chemical Industry.

Dietary lipids, gut microbiota and lipid metabolism

The gut microbiota is a central regulator of host metabolism. The composition and function of the gut microbiota is dynamic and affected by diet properties such as the amount and composition of lipids. Hence, dietary lipids may influence host physiology through interaction with the gut microbiota. Lipids affect the gut microbiota both as substrates for bacterial metabolic processes, and by inhibiting bacterial growth by toxic influence. The gut microbiota has been shown to affect lipid metabolism and lipid levels in blood and tissues, both in mice and humans. Furthermore, diseases linked to dyslipidemia, such as non-alcoholic liver disease and atherosclerosis, are associated with changes in gut microbiota profile. The influence of the gut microbiota on host lipid metabolism may be mediated through metabolites produced by the gut microbiota such as short-chain fatty acids, secondary bile acids and trimethylamine and by pro-inflammatory bacterially derived factors such as lipopolysaccharide. Here we will review the association between gut microbiota, dietary lipids and lipid metabolism.

Antimicrobial lipids in nano-carriers for antibacterial delivery

Antimicrobial lipids have been recognised as broad-spectrum antibacterial agents. They can directly act on and lyse bacterial cell membrane, and inhibit bacterial growth through a range of mechanisms. Antimicrobial lipids include free fatty acids, monoglycerides, cholesteryl ester, sphingolipids and etc., with the first two being the most extensively studied. Their application is usually hindered by the low solubility of the compounds themselves, and nano-sized lipid-based carriers can endow druggability to these antimicrobial agents for they improve lipid solubility and dispersion in aqueous formulations. Nano-carriers also possess advantages in overcoming drug resistance. In this review we will discuss different kinds of antimicrobial lipids in nano-sized carriers for antibacterial delivery. CAL02 as a promising infection-controlling liposome consisted of cholesterol and sphingomyelin will also be included for it's a unique anti-infection approach, which signifies that the underlying antibacterial roles antimicrobial lipids needs to be further addressed. With the global emergence of antibiotic resistance, antimicrobial lipids formulated in nano-carriers might provide a novel alternative in combatting infectious diseases.

Delivering amoxicillin at the infection site - a rational design through lipid nanoparticles

Purpose

Amoxicillin is a commonly used antibiotic, although degraded by the acidic pH of the stomach. This is an important limitation for the treatment of Helicobacter pylori infections. The purpose of this work was to encapsulate amoxicillin in lipid nanoparticles, increasing the retention time at the site of infection (gastric mucosa), while protecting the drug from the harsh conditions of the stomach lumen.

Materials and methods

The nanoparticles were produced by the double emulsion technique and optimized by a three-level Box-Behnken design. Tween 80 and linolenic acid were used as potential therapeutic adjuvants and dioleoylphosphatidylethanolamine as a targeting agent to Helicobacter pylori. Nanoparticles were characterized regarding their physico-chemical features, their storage stability, and their usability for oral administration (assessment of in vitro release, in vitro cell viability, permeability, and interaction with mucins).

Results

The nanoparticles were stable for at least 6 months at 4°C. In vitro release studies revealed a high resistance to harsh conditions, including acidic pH and physiologic temperature. The nanoparticles have a low cytotoxicity effect in both fibroblasts and gastric cell lines, and they have the potential to be retained at the gastric mucosa.

Conclusion

Overall, the designed formulations present suitable physico-chemical features for being henceforward used by oral administration to treat Helicobacter pylori infections.

Characterizing the Membrane-Disruptive Behavior of Dodecylglycerol Using Supported Lipid Bilayers

Monoglycerides are esterified adducts of fatty acid and glycerol molecules that disrupt phospholipid membranes, leading to a wide range of biological functions such as antimicrobial activity. Among monoglycerides, glycerol monolaurate (GML) exhibits particularly high antimicrobial activity, although enzymatic hydrolysis of its ester group can diminish potency. Consequently, there have been efforts to identify more chemically stable versions of GML, most notably its alkylglycerol ether equivalent called dodecylglycerol (DDG). However, despite high structural similarity, biological studies indicate that DDG and GML are not functionally equivalent and it has been speculated that the two compounds might have different interaction profiles with phospholipid membranes. To address this outstanding question, herein, we employed supported lipid bilayer (SLB) platforms to experimentally characterize the interactions of DDG with phospholipid membranes. Quartz crystal microbalance-dissipation experiments identified that DDG causes concentration-dependent membrane morphological changes in SLBs and the overall extent of membrane remodeling events was greater than that caused by GML. In addition, time-lapsed fluorescence microscopy imaging experiments revealed that DDG causes extensive membrane tubulation that is distinct from how GML induces membrane budding. We discuss how differences in the head group properties of DDG and GML contribute to distinct membrane interaction profiles, offering insight into how the molecular design of DDG not only improves chemical stability but also enhances membrane-disruptive activity.

Effectiveness of omega-3 polyunsaturated fatty acids against microbial pathogens

Microorganisms provide both beneficial and harmful effects to human beings. Beneficial effects come from the symbiotic relationship that exists between humans and microbiota, but then several human illnesses have turned some friendly microbes into opportunistic pathogens, causing several microbial-related diseases. Various efforts have been made to create and utilize antimicrobial agents in the treatment and prevention of these infections, but such efforts have been hampered by the emergence of antimicrobial resistance. Despite extensive studies on drug discovery to alleviate this problem, issues with the toxicity and tolerance of certain compounds and continuous microbial evolution have forced researchers to focus on screening various phytochemical dietary compounds for antimicrobial activity. Linolenic acid and its derivatives (eicosapentaenoic acid and docosahexaenoic acid) are omega-3 fatty acids that have been studied due to their role in human health, being important for the brain, the eye, the cardiovascular system, and general human growth. However, their utilization as antimicrobial agents has not been widely appreciated, perhaps due to a lack of understanding of antimicrobial mechanisms, toxicity, and route of administration. Therefore, this review focuses on the efficacy, mechanism, and toxicity of omega-3 fatty acids as alternative therapeutic agents for treating and preventing diseases associated with pathogenic microorganisms.

Materials Nanoarchitectonics for Mechanical Tools in Chemical and Biological Sensing

In this Focus Review, nanoarchitectonic approaches for mechanical-action-based chemical and biological sensors are briefly discussed. In particular, recent examples of piezoelectric devices, such as quartz crystal microbalances (QCM and QCM-D) and a membrane-type surface stress sensor (MSS), are introduced. Sensors need well-designed nanostructured sensing materials for the sensitive and selective detection of specific targets. Nanoarchitectonic approaches for sensing materials, such as mesoporous materials, 2D materials, fullerene assemblies, supported lipid bilayers, and layer-by-layer assemblies, are highlighted. Based on these sensing approaches, examples of bioanalytical applications are presented for toxic gas detection, cell membrane interactions, label-free biomolecular assays, anticancer drug evaluation, complement activation-related multiprotein membrane attack complexes, and daily biodiagnosis, which are partially supported by data analysis, such as machine learning and principal component analysis.

Anaerobic digestion of thermal pre-treated emulsified slaughterhouse wastes (TESW): Effect of trace element limitation on process efficiency and sludge metabolic properties

Slaughterhouse solid wastes, characterized by a high lipid content, are considered a valuable resource for energy production by means of anaerobic digestion technologies. Aim of this study was to examine the effect of trace element limitation on the mesophilic anaerobic digestion of thermally pre-treated emulsified slaughterhouse wastes (TESW). Under two distinct experimental periods (Period I - low and Period II - high trace element dosage respectively) a CSTR with sludge recirculation was operated at increasing organic loading rate (OLR) from 1.5 to 10 g L^-1 d^-1. Under optimum conditions, COD removal was higher than 96%, biogas yield equal to 0.53 L g^-1 COD feed and the biogas methane content 77%. Trace element limitation however, resulted in a dramatic decline in process efficiency, with VFA accumulation and events of extreme sludge flotation, despite that the soluble concentration of Ni, Co and Mo were between 12 and 28 μg L^-1. This is indicative of mass transfer limitations caused by lipids adsorption onto the anaerobic biomass.

Arachidonic Acid Stress Impacts Pneumococcal Fatty Acid Homeostasis

Free fatty acids hold dual roles during infection, serving to modulate the host immune response while also functioning directly as antimicrobials. Of particular importance are the long chain polyunsaturated fatty acids, which are not commonly found in bacterial organisms, that have been proposed to have antibacterial roles. Arachidonic acid (AA) is a highly abundant long chain polyunsaturated fatty acid and we examined its effect upon Streptococcus pneumoniae. Here, we observed that in a murine model of S. pneumoniae infection the concentration of AA significantly increases in the blood. The impact of AA stress upon the pathogen was then assessed by a combination of biochemical, biophysical and microbiological assays. In vitro bacterial growth and intra-macrophage survival assays revealed that AA has detrimental effects on pneumococcal fitness. Subsequent analyses demonstrated that AA exerts antimicrobial activity via insertion into the pneumococcal membrane, although this did not increase the susceptibility of the bacterium to antibiotic, oxidative or metal ion stress. Transcriptomic profiling showed that AA treatment also resulted in a dramatic down-regulation of the genes involved in fatty acid biosynthesis, in addition to impacts on other metabolic processes, such as carbon-source utilization. Hence, these data reveal that AA has two distinct mechanisms of perturbing the pneumococcal membrane composition. Collectively, this work provides a molecular basis for the antimicrobial contribution of AA to combat pneumococcal infections.