Testing Antimicrobial Properties of Human Lactoferrin-Derived Fragments

Lactoferrin, an iron-binding glycoprotein, plays a significant role in the innate immune system, with antibacterial, antivirial, antifungal, anticancer, antioxidant and immunomodulatory functions reported. It is worth emphasizing that not only the whole protein but also its derived fragments possess antimicrobial peptide (AMP) activity. Using AmpGram, a top-performing AMP classifier, we generated three novel human lactoferrin (hLF) fragments: hLF 397-412, hLF 448-464 and hLF 668-683, predicted with high probability as AMPs. For comparative studies, we included hLF 1-11, previously confirmed to kill some bacteria. With the four peptides, we treated three Gram-negative and three Gram-positive bacterial strains. Our results indicate that none of the three new lactoferrin fragments have antimicrobial properties for the bacteria tested, but hLF 1-11 was lethal against Pseudomonas aeruginosa. The addition of serine protease inhibitors with the hLF fragments did not enhance their activity, except for hLF 1-11 against P. aeruginosa, which MIC dropped from 128 to 64 µg/mL. Furthermore, we investigated the impact of EDTA with/without serine protease inhibitors and the hLF peptides on selected bacteria. We stress the importance of reporting non-AMP sequences for the development of next-generation AMP prediction models, which suffer from the lack of experimentally validated negative dataset for training and benchmarking.

Oilseed Supplementation Improves Milk Composition and Fatty Acid Profile of Cow Milk: A Meta-Analysis and Meta-Regression

Oilseed supplementation is a strategy to improve milk production and milk composition in dairy cows; however, the response to this approach is inconsistent. Thus, the aim of this study was to evaluate the effect of oilseed supplementation on milk production and milk composition in dairy cows via a meta-analysis and meta-regression. A comprehensive and structured search was performed using the following electronic databases: Google Scholar, Primo-UAEH and PubMed. The response variables were: milk yield (MY), atherogenic index (AI), Σ omega-3 PUFA, Σ omega-6 PUFA, fat, protein, lactose, linoleic acid (LA), linolenic acid (LNA), oleic acid (OA), vaccenic acid (VA), conjugated linoleic acid (CLA), unsaturated fatty acid (UFA) and saturated fatty acid (SFA) contents. The explanatory variables were breed, lactation stage (first, second, and third), oilseed type (linseed, soybean, rapeseed, cottonseed, and sunflower), way (whole, extruded, ground, and roasted), dietary inclusion level, difference of the LA, LNA, OA, forage and NDF of supplemented and control rations, washout period and experimental design. A meta-analysis was performed with the “meta” package of the statistical program R. A meta-regression analysis was applied to explore the sources of heretogeneity. The inclusion of oilseeds in dairy cow rations had a positive effect on CLA (+0.27 g 100 g−1 fatty acids (FA); p < 0.0001), VA (+1.03 g 100 g−1 FA; p < 0.0001), OA (+3.44 g 100 g−1 FA; p < 0.0001), LNA (+0.28 g 100 g−1 FA; p < 0.0001) and UFA (+8.32 g 100 g−1 FA; p < 0.0001), and negative effects on AI (−1.01; p < 0.0001), SFA (−6.51; p < 0.0001), fat milk (−0.11%; p < 0.001) and protein milk (−0.04%; p < 0.007). Fat content was affected by animal breed, lactation stage, type and processing of oilseed and dietary NDF and LA contents. CLA, LA, OA and UFA, desirable FA milk components, were affected by type, processing, and the intake of oilseed; additionally, the concentrations of CLA and VA are affected by washout and design. Oilseed supplementation in dairy cow rations has a positive effect on desirable milk components for human consumption. However, animal response to oilseed supplementation depends on explanatory variables related to experimental design, animal characteristics and the type of oilseed.

Lactoferrin: A Nutraceutical with Activity against Colorectal Cancer

Homeostasis in the human body results from the tight regulation of several events, since too little inflammation disrupts the process of tissue repair and remodeling, whereas too much exerts a collateral effect by causing tissue damage with life-threatening consequences. In some clinical conditions, such as inflammatory bowel disease (IBD), inflammation functions as a double-edged sword by either enabling or inhibiting cancer development and progression. Generally, cancer develops through evasion mechanisms that regulate cell growth, causing a high rate of uncontrolled proliferation, and mechanisms for evading cell death, such as apoptosis. Moreover, chronic inflammation is a factor that contributes to colorectal cancer (CRC), as observed in individuals with IBD; all these conditions favor an increased rate of angiogenesis and eventual metastasis. Lactoferrin (Lf) is a mammalian iron-binding multifunctional glycoprotein regarded as a natural compound that up- and downregulates both humoral and cellular components of immunity involved in regulating the inflammatory response and maintaining gut homeostasis. Human and bovine Lf share high sequence homology and have very similar antimicrobial, anti-inflammatory, and immunomodulatory activities. Bovine Lf from milk is considered a safe molecule and is commercially available in large quantities. This review mainly focuses on the regulatory effects of orally administered bovine Lf on the inflammatory response associated with CRC; this approach indicates that CRC is one of the most frequently diagnosed cancers and affects the intestinal tract with high clinical and epidemiologic relevance. Thus, this review may provide foundations for the potential use of bovine Lf alone or as a natural adjunct agent to increase the effectiveness and reduce the side effects of anticancer chemotherapy.

Iron supplementation and iron-fortified foods: a review

About one-third of the world population is suffering from iron deficiency. Delivery of iron through diet is a practical, economical, and sustainable approach. Clinical studies have shown that the consumption of iron-fortified foods is one of the most effective methods for the prevention of iron deficiency. However, supplementing iron through diet can cause undesirable side-effects. Thus, it is essential to develop new iron-rich ingredients, iron-fortified products with high bioavailability, better stability, and lower cost. It is also essential to develop newer processing technologies for more effective fortification. This review compared the iron supplementation strategies used to treat the highly iron-deficient population and the general public. We also reviewed the efficacy of functional (iron-rich) ingredients that can be incorporated into food materials to produce iron-fortified foods. The most commonly available foods, such as cereals, bakery products, dairy products, beverages, and condiments are still the best vehicles for iron fortification and delivery.Scope of reviewThe manuscript aims at providing a comprehensive review of the latest publications that cover three aspects: administration routes for iron supplementation, iron-rich ingredients used for iron supplementation, and iron-fortified foods.

Concentrations of mercury and other elements in ewes' milk: Effect of lactation stage

There is an increased production and demand for ewes' milk in the Republic of Croatia, as well as globally. There is also a growing concern about its quality, since milk from farm animals may become contaminated with mercury and other toxic elements. Thus, the aim of this paper is to determine the influence of lactation stage on the ewes' milk quality in western Croatia by considering concentrations of mercury and other elements in ewes' milk. The research was conducted on 36 Travnik pramenka sheep during different lactation stages. The digested milk samples were analysed with continuous flow hydride generation technique by using inductively coupled plasma mass spectrometry. Samples were taken during 40th, 80th and 120th d of lactation. Yield and quality of ewes' milk was within lactation curve. As lactation progressed, significantly lower concentrations of Hg (on 80th d compared to 40th d) and of Cd (120th d compared to 80th d) were noted, and Hg on 120th d was below the detection limit. Concentrations of Ca and Cu were lower on the 120th d compared to 40th d, while P, Mg, Fe, Zn, Mn, and Se were lower on the 80th and 120th d compared to the 40th d. Concentrations of K, Mo, and Cr differed among all stages of lactation. Regarding toxic elements, the observed low concentrations of Hg, Co, Cd and As suggest that ewes' milk in western Croatia is safe for human or animal consumption.

The "Grass-Fed" Milk Story: Understanding the Impact of Pasture Feeding on the Composition and Quality of Bovine Milk

Milk is a highly nutritious food that contains an array of macro and micro components, scientifically proven to be beneficial to human health. While the composition of milk is influenced by a variety of factors, such as genetics, health, lactation stage etc., the animal's diet remains a key mechanism by which its nutrition and processing characteristics can be altered. Pasture feeding has been demonstrated to have a positive impact on the nutrient profile of milk, increasing the content of some beneficial nutrients such as Omega-3 polyunsaturated fatty acids, vaccenic acid, and conjugated linoleic acid (CLA), while reducing the levels of Omega-6 fatty acids and palmitic acid. These resultant alterations to the nutritional profile of "Grass-Fed" milk resonate with consumers that desire healthy, "natural", and sustainable dairy products. This review provides a comprehensive comparison of the impact that pasture and non-pasture feeding systems have on bovine milk composition from a nutritional and functional (processability) perspective, highlighting factors that will be of interest to dairy farmers, processors, and consumers.

Flexible nanopillar-based electrochemical sensors for genetic detection of foodborne pathogens

Flexible and highly ordered nanopillar arrayed electrodes have brought great interest for many electrochemical applications, especially to the biosensors, because of its unique mechanical and topological properties. Herein, we report an advanced method to fabricate highly ordered nanopillar electrodes produced by soft-/photo-lithography and metal evaporation. The highly ordered nanopillar array exhibited the superior electrochemical and mechanical properties in regard with the wide space to response with electrolytes, enabling the sensitive analysis. As-prepared gold and silver electrodes on nanopillar arrays exhibit great and stable electrochemical performance to detect the amplified gene from foodborne pathogen of Escherichia coli O157:H7. Additionally, lightweight, flexible, and USB-connectable nanopillar-based electrochemical sensor platform improves the connectivity, portability, and sensitivity. Moreover, we successfully confirm the performance of genetic analysis using real food, specially designed intercalator, and amplified gene from foodborne pathogens with high reproducibility (6% standard deviation) and sensitivity (10 × 1.01 CFU) within 25 s based on the square wave voltammetry principle. This study confirmed excellent mechanical and chemical characteristics of nanopillar electrodes have a great and considerable electrochemical activity to apply as genetic biosensor platform in the fields of point-of-care testing (POCT).

Dietary N-Glycans from Bovine Lactoferrin and TLR Modulation

SCOPE

Bovine lactoferrin (bLF) is an ingredient of food supplements and infant formulas given its antimicrobial and antiviral properties. We modified bLF enzymatically to alter its N-glycosylation and to isolate the glycan chains. The aims of this study include (1) to evaluate whether such derivates induce responses via pattern recognition receptors namely Toll-like receptors (TLRs) and (2) to relate those responses to their different glycosylation profiles.

METHODS AND RESULTS

The unmodified and modified bLF fractions are incubated with reporter cell lines expressing pattern recognition receptors. Afterwards, we screen for TLRs and analyze for nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) activation. Activation of reporter cell lines show that signaling is highly dependent on TLRs. The activation pattern of bLF is reduced with the desialylated form and increased with the demannosylated form. In reporter cells for TLR, bLF activate TLR-4 and inhibit TLR-3. The isolated glycans from bLF inhibit TLR-8. TLR-2, TLR-5, TLR-7, and TLR-9 are not significantly altered.

CONCLUSION

The profile of glycosylation is key for the biological activity of bLF. By understanding how this affects the human defense responses, the bLF glycan profile can be modified to enhance its immunomodulatory effects when used as a dietary ingredient.

Bifunctional linker-based immunosensing for rapid and visible detection of bacteria in real matrices

Detection of pathogens present in food and water is essential to help ensure food safety. Among the popular methods for pathogen detection are those based on culture and colony-counting and polymerase chain reaction (PCR). However, the time-consuming nature and/or the need for sophisticated instrumentation of those methods limit their on-site applications. We have developed a rapid and highly sensitive immunosensing method for visible detection of bacteria in real matrices based on the aggregation of AuNPs without requiring any readout device. We use biotinylated anti-bacteria antibodies as bifunctional linkers (BLs) to mediate the aggregation of streptavidin-functionalized gold nanoparticles (st-AuNPs) to produce visually recognizable color change, due to surface plasmon resonance (SPR), which occurs in about 30min of total assay time when the sample is mildly agitated or within three hours in quiescent conditions. The aggregation of st-AuNPs, which produces the indication signal, is achieved very differently than in visual detection methods reported previously and hence affords ultrahigh sensitivity. While BLs can both bind to the target and crosslink st-AuNPs, their latter function is essentially disabled when they bind to the target bacteria. By varying the amount of st-AuNPs used, we can tailor the assay effectiveness improving limit of detection (LOD) down to 10CFUmL^-1 of E. coli and Salmonella. Test results obtained with tap water, lake water and milk samples show that assay performance is unaffected by matrix effects. Further, in a mixture of live and autoclaved E. coli cells our assay could detect only live cells. Therefore, our BL-based immunosensor is suitable for highly sensitive, rapid, and on-site detection of bacteria in real matrices.

Studying Lactoferrin N-Glycosylation

Lactoferrin is a multifunctional glycoprotein found in the milk of most mammals. In addition to its well-known role of binding iron, lactoferrin carries many important biological functions, including the promotion of cell proliferation and differentiation, and as an anti-bacterial, anti-viral, and anti-parasitic protein. These functions differ among lactoferrin homologs in mammals. Although considerable attention has been given to the many functions of lactoferrin, its primary nutritional contribution is presumed to be related to its iron-binding characteristics, whereas the role of glycosylation has been neglected. Given the critical role of glycan binding in many biological processes, the glycan moieties in lactoferrin are likely to contribute significantly to the biological roles of lactoferrin. Despite the high amino acid sequence homology in different lactoferrins (up to 99%), each exhibits a unique glycosylation pattern that may be responsible for heterogeneity of the biological properties of lactoferrins. An important task for the production of biotherapeutics and medical foods containing bioactive glycoproteins is the assessment of the contributions of individual glycans to the observed bioactivities. This review examines how the study of lactoferrin glycosylation patterns can increase our understanding of lactoferrin functionality.

High pressure effects on the structural functionality of condensed globular-protein matrices

High pressure technology is the outcome of consumer demand for better quality control of processed foods. There is great potential to apply HPP to condensed systems of globular proteins for the generation of industry-relevant biomaterials with advanced techno- and biofunctionality. To this end, research demonstrates that application of high hydrostatic pressure generates a coherent structure and preserves the native conformation in condensed globular proteins, which is an entirely unexpected but interesting outcome on both scientific and technological grounds. In microbiological challenge tests, high pressure at conventional commercial conditions, demonstrated to effectively reduce the concentration of typical Gram negative or Gram positive foodborne pathogens, and proteolytic enzymes in high-solid protein samples. This may have industrial significance in relation to the formulation and stabilisation of "functional food" products as well as in protein ingredients and concentrates by replacing spray dried powders with condensed HPP-treated pastes that maintain structure and bioactivity. Fundamental concepts and structural functionality of condensed matrices of globular proteins are the primary interest in this mini-review, which may lead to opportunities for industrial exploitation, but earlier work on low-solid systems is also summarised presently to put recent developments in context of this rapidly growing field.

Structural and functional characteristics of bovine milk protein glycosylation

Most secreted and cell membrane proteins in mammals are glycosylated. Many of these glycoproteins are also prevalent in milk and play key roles in the biomodulatory properties of milk and ultimately in determining milk's nutritional quality. Although a significant amount of information exists on the types and roles of free oligosaccharides in milk, very little is known about the glycans associated with milk glycoproteins, in particular, the biological properties that are linked to their presence. The main glycoproteins found in bovine milk are lactoferrin, the immunoglobulins, glycomacropeptide, a glycopeptide derived from κ-casein, and the glycoproteins of the milk fat globule membrane. Here, we review the glycoproteins present in bovine milk, the information currently available on their glycosylation and the biological significance of their oligosaccharide chains.

Bioactive peptides derived from milk proteins and their health beneficial potentials: an update

It has been well recognized that dietary proteins provide a rich source of biologically active peptides. Today, milk proteins are considered the most important source of bioactive peptides and an increasing number of bioactive peptides have been identified in milk protein hydrolysates and fermented dairy products. Bioactive peptides derived from milk proteins offer a promising approach for the promotion of health by means of a tailored diet and provide interesting opportunities to the dairy industry for expansion of its field of operation. The potential health benefits of milk protein-derived peptides have been a subject of growing commercial interest in the context of health-promoting functional foods. Hence, these peptides are being incorporated in the form of ingredients in functional and novel foods, dietary supplements and even pharmaceuticals with the purpose of delivering specific health benefits.

Determination of lactoferrin and immunoglobulin g in animal milks by new immunosensors

Two different immunosensors, recently developed for the determination of antibacterial proteins (lactoferrin and immunoglobulin G) in buffalo milk and in other commercial animal milks samples, were used in the present study. The aim was to propose these immunosensor methods for routine control of important diet products, such as cow and goat milks, and in particular buffalo milk. To this end we employed two different kinds of immunosensors: one for the analysis of immunoglobulin G (IgG), the other was a new amperometric immunosensor for lactoferrin analysis. Lactoferrin and IgG immunosensors were also used for the determination of lactoferrin and immunoglobulin G in buffalo milk on different days of lactation.

Milk biologically active components as nutraceuticals: review

Milk contains components that provide critical nutritive elements, immunological protection, and biologically active substances to both neonates and adults. Milk proteins are currently the main source of a range of biologically active peptides. Concentrates of these peptides are potential health-enhancing nutraceuticals for food and pharmaceutical applications. Several bioactive peptides may be used as nutraceuticals, for example, in the treatment of diarrhea, hypertension, thrombosis, dental diseases, as well as mineral malabsorption, and immunodeficiency. Minor whey proteins, such as lactoferrin, lactoperoxidase, lysozyme, and immunoglobulins, are considered antimicrobial proteins. Milk also contains some natural bioactive substances. These include oligosaccharides, fucosylated oligosaccharides, hormones, growth factors, mucin, gangliosides, and endogenous peptides, which are present in milk at secretion. Most of the claimed physiological properties of milk bioactive components have been carried out in vitro or in animal model systems, and these hypothesized properties remain to be proven in humans. Whether these milk bioactive components will replace drugs entirely in the immediate future is still unclear, but the increasing appreciation of "drug foods" or nutraceuticals plays a complementary rather than a substitutional role to the synthetic pharmacological drugs.

Oral tryptic casein hydrolysate enhances phagocytosis by mouse peritoneal and blood phagocytic cells but fails to prevent induced inflammation

Mouse experiments were conducted in order to find whether oral application of tryptic casein hydrolysate (TCH) results in enhancement of phagocytosing capacity of murine phagocytic cells as well as whether such application might be of use for prevention of inflammatory processes. Phagocytosing capacity of phagocytic cells of mice that received oral TCH once daily in a dose of 1.0 mg/g body weight dissolved in 0.5 ml of distilled water for five successive days was significantly higher (p < 0.05) than that of mice given equivalent volumes of distilled water, with a phagocytosing capacity enhancement index being 1.39 and 1.34 regarding peritoneal macrophages and blood phagocytic cells, respectively. Taken on the other hand, the immunostimulatory effects of oral TCH were found to be not enough to prevent mice from inflammation that was induced experimentally using acute (paw edema) and contact hypersensitivity models. A possibility for development of food protein enzymatic hydrolysates as antimicrobial immunostimulants acting through improvement of phagocytic cell functioning is discussed.

Bioactive properties of milk proteins with particular focus on anticariogenesis

Beyond nutrition, there is an increasing amount of data and information to demonstrate a bioactive role for dairy components in adults including a role in prevention of dental caries. Specifically, the casein fraction and hydrolysates thereof have been the focus of researchers investigating cariogenicity prevention. Tooth enamel is a polymeric substance consisting of crystalline calcium phosphate embedded in a protein matrix. Dental caries develop by acidic demineralization (calcium and phosphorus solubilization) of tooth enamel. Demineralization occurs directly (acidic food consumption) or indirectly (by fermentation products of dental plaque odontopathogenic bacteria growing on residual food particles between teeth or adhering to the plaque). Research efforts with milk derived bioactive peptides have focused on inhibition of cariogenic, plaque-forming bacteria, inhibition of tooth enamel demineralization, and subsequent enamel remineralization. Caseinophosphopeptides (CPP) and glycomacropeptide (GMP) have been patented for use in common personal hygiene products to prevent dental caries. Research has shown CPP and GMP to be growth inhibitory to the cariogenic bacteria Streptococcus mutans and other species. Additionally, CPP forms nanoclusters with amorphous calcium phosphate (AMP) at the tooth surface to provide a reservoir of calcium and phosphate ions to maintain a state of super saturation with respect to tooth enamel. This would buffer plaque pH, and also provide ions for tooth enamel remineralization. Glycosidic structures attached to GMP are important to numerous bioactive properties of the peptide including anticariogenicity. Like CPP, GMP has shown inhibitory activity to enamel demineralization and promotes tooth enamel remineralization.