Increase of viability of entrapped cells of Lactobacillus delbrueckii ssp. bulgaricus in artificial sesame oil emulsions

Unveiling the applications of membrane proteins from oil bodies: leading the way in artificial oil body technology and other biotechnological advancements

Oil bodies (OBs) function as organelles that store lipids in plant seeds. An oil body (OB) is encased by a membrane composed of proteins (e.g., oleosins, caleosins, and steroleosins) and a phospholipid monolayer. The distinctive protein-phospholipid membrane architecture of OBs imparts exceptional stability even in extreme environments, thereby sparking increasing interest in their structure and properties. However, a comprehensive understanding of the structure-activity relationships determining the stability and properties of oil bodies requires a more profound exploration of the associated membrane proteins, an aspect that remains relatively unexplored. In this review, we aim to summarize and discuss the structural attributes, biological functions, and properties of OB membrane proteins. From a commercial perspective, an in-depth understanding of the structural and functional properties of OBs is important for the expansion of their applications by producing artificial oil bodies (AOB). Besides exploring their structural intricacies, we describe various methods that are used for purifying and isolating OB membrane proteins. These insights may provide a foundational framework for the practical utilization of OB membrane proteins in diverse applications within the realm of AOB technology, including biological and probiotic delivery, protein purification, enzyme immobilization, astringency detection, and antibody production.

Effect of oil exposure stages on the heat resistance of Salmonella enterica serovar Enteritidis phage type 30 in peanut flour

The oil in low-moisture foods (LMFs) shows protective effects on bacteria during thermal processing. However, the circumstances under which this protective effect strengthens remain unclear. This study aimed to understand which step of the oil exposure to bacterial cells (inoculation, isothermal inactivation, or recovery and enumeration step) in LMFs can enhance their heat resistance. Peanut flour (PF) and defatted PF (DPF) were selected as the oil-rich and oil-free LMF models. Salmonella enterica Enteritidis Phage Type 30 (S. Enteritidis) was inoculated into four designated PF groups representing different oil exposure stages. It was isothermally treated to obtain heat resistance parameters. At a constant moisture content (a_w,25°C = 0.32 ± 0.02) and controlled a_w,85°C (0.32 ± 0.02), S. Enteritidis exhibited significantly high (p < 0.05) D values in oil-rich sample groups. For instance, the heat resistance values of S. Enteritidis in the PF-DPF and DPF-PF groups were D_80°C of 138.22 ± 7.45 min and 101.89 ± 7.82 min; however, the D_80°C in the DPF-DPF group was 34.54 ± 2.07 min. The oil addition after the thermal treatment also helped injured bacterial recovery in the enumeration. For instance, the D_80°C, D_85°C, and D_90°C values in the DFF-DPF oil groups were 36.86 ± 2.30, 20.65 ± 1.23, and 7.91 ± 0.52 min, respectively, which were higher than those in the DPF-DPF group at 34.54 ± 2.07, 17.87 ± 0.78, and 7.10 ± 0.52 min. We confirmed that the oil protected S. Enteritidis in PF in all three stages: desiccation process, heat treatment, and recovery of bacterial cells in plates.

Immunostimulatory activity of Lactococcus lactis LM1185 isolated from Hydrangea macrophylla

The lactic acid bacteria, Lactococcus lactis subsp. lactis LM1185 was isolated from Hydrangea macrophylla. Strain LM1185 showed 50.5% of acid tolerance at pH 2.5 for 2 h and 30.4% of 0.3% (w/v) bile salt tolerance for 24 h. The antioxidant activity of this strain was measured at 99.4% of 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity. When RAW 264.7 macrophage cells were treated with strain LM1185, there was no observed cytotoxicity. This strain showed high nitric oxide production and mRNA expression levels of cytokines such as tumor necrosis factor-α and inducible nitric oxide synthase (iNOS). The nuclear factor-kB signaling pathway was activated by this strain resulting in the production of iNOS and cyclooxygenase-2 determined by western blotting. The present results indicated that L. lactis subsp. lactis LM1185 could be used as potential probiotics and may play a crucial role in the immunostimulatory effect on macrophages.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01199-5.

The Effect of Bacteria on the Stability of Microfluidic-Generated Water-in-Oil Droplet

Microencapsulation in emulsion droplets has great potential for various applications such as food which require formation of highly stable emulsions. Bacterial-emulsion interactions affect the physiological status of bacteria while bacterial cell characteristics such as surface-active properties and metabolic activity can affect emulsion stability. In this study, the viability and growth of two different bacterial species, Gram-negative Escherichia coli and Gram-positive Lactobacillus paracasei, encapsulated in water-in-oil (W/O) droplets or as planktonic cells, were monitored and their effect on droplet stability was determined. Microencapsulation of bacteria in W/O droplets with growth media or water was achieved by using a flow-focusing microfluidic device to ensure the production of highly monodispersed droplets. Stability of W/O droplets was monitored during 5 days of storage. Fluorescence microscopy was used to observe bacterial growth behaviour. Encapsulated cells showed different growth to planktonic cells. Encapsulated E. coli grew faster initially followed by a decline in viability while encapsulated L. paracasei showed a slow gradual growth throughout storage. The presence of bacteria increased droplet stability and a higher number of dead cells was found to provide better stability due to high affinity towards the interface. The stability of the droplets is also species dependent, with E. coli providing better stability as compared to Lactobacillus paracasei.

Long-Term Lacticaseibacillus rhamnosus GG Storage at Ambient Temperature in Vegetable Oil: Viability and Functional Assessments

Vegetable oils with varying saturated fat levels were inoculated with Lacticaseibacillus rhamnosus GG (LGG), subjected to different heat treatments in the absence and presence of inulin and stored for 12 months at room temperature. After storage, the heat-treated probiotics actively grew to high concentrations after removal of the oils and reculturing. The bacterial samples, regardless of aerobic or anaerobic conditions and treatment methods, showed no changes in their growth behavior. The random amplified polymorphic DNA-polymerase chain reaction, antimicrobial, morphology, and motility tests also showed no major differences. Samples of LGG treated with a higher antioxidant content (Gal400) showed reduced inflammatory and anti-inflammatory properties. These findings have been confirmed by metabolite and genome sequencing studies, indicating that Gal400 showed lower concentrations and secretion percentages and the highest number of single nucleotide polymorphisms. We have shown proof of concept that LGG can be stored in oil with minimum impact on probiotic in vitro viability.

Advancements in the Pharmaceutical Applications of Probiotics: Dosage Forms and Formulation Technology

Probiotics have demonstrated their high potential to treat and/or prevent various diseases including neurodegenerative disorders, cancers, cardiovascular diseases, and inflammatory diseases. Probiotics are also effective against multidrug-resistant pathogens and help maintain a balanced gut microbiota ecosystem. Accordingly, the global market of probiotics is growing rapidly, and research efforts to develop probiotics into therapeutic adjuvants are gaining momentum. However, because probiotics are living microorganisms, many biological and biopharmaceutical barriers limit their clinical application. Probiotics may lose their activity in the harsh gastric conditions of the stomach or in the presence of bile salts. Moreover, they easily lose their viability under thermal or oxidative stress during their preparation and storage. Therefore, stable formulations of probiotics are required to overcome the various physicochemical, biopharmaceutical, and biological barriers and to maximize their therapeutic effectiveness and clinical applicability. This review provides an overview of the pharmaceutical applications of probiotics and covers recent formulation approaches to optimize the delivery of probiotics with particular emphasis on various dosage forms and formulation technologies.

Reviewing the biological activity of chitosan in the mucosa: Focus on intestinal immunity

Chitosan is a polymer derived from the partial deacetylation of chitin with particular characteristics, such as mucoadhesiveness, tolerability, biocompatibility and biodegradability. Biomedical uses of chitosan cover a wide spectrum of applications as dietary fiber, immunoadjuvant and regulator of the intestinal microbiota or delivery agent. Chemical modification of chitosan is feasible because its reactive amino and hydroxyl groups can be modified by a diverse array of ligands, functional groups and molecules. This gives rise to numerous derivatives that allow different formulation types influencing their activity. Considering the multiple events resulting from the interaction with mucosal tissues, chitosan is a singular candidate for strategies targeting immune stimulation (i.e., tolerance induction, vaccination). Its role as a prebiotic and probiotic carrier represents an effective option to manage intestinal dysbiosis. In the intestinal scenario where the exposure of the immune system to a wide variety of antigens is permanent, chitosan increases IgA levels and favors a tolerogenic environment, thus becoming a key ally for host homeostasis.

The Evolution of Human Probiotics: Challenges and Prospects

In recent years, the intestinal microbiota has been found to greatly influence a number of biological processes important for human health and longevity. Microbial composition changes easily in response to external factors, such as an unbalanced diet, lack of physical activity, and smoking. Probiotics are a key factor in maintaining the optimal composition of the intestinal microbiota. However, a number of important questions related to probiotics, such as indication for prescription, comparative efficacy of monostrain and multistrain probiotics, methods of delivery, and shelf life, remain unresolved. The aim of this review is to highlight existing issues regarding probiotic production and their prescription. The review presents the most recent findings regarding advantages and efficacy of monostrain and multistrain probiotics, preservation of probiotic strains in capsules and microcapsules, production of probiotics in the form of biofilms for improved efficacy and survival, and results of clinical studies evaluating the benefits of probiotics against different pathologies. We believe that this work will be of interest to physicians and researchers alike and will promote the development of new probiotics and ensuing regimens aimed at the treatment of various diseases.

Fishing for the right probiotic: Host-microbe interactions at the interface of effective aquaculture strategies

Effective aquaculture management strategies are paramount to global food security. Growing demands stimulate the intensification of production and create the need for practices that are both economically viable and environmentally sustainable. Importantly, pathogenic microbes continue to be detrimental to fish growth and survival. In terms of host health, the intestinal mucosa and its associated consortium of microbes have a critical role in modulating fitness and present an attractive opportunity to promote health at this interface. In light of this, the administration of probiotic microorganisms is being considered as a means to restore and sustain health in fish. Current evidence suggests that certain probiotic strains might be able to augment immunity, enhance growth rate, and protect against infection in salmonids, the most economically important family of farmed finfish. This review affirms the relevance of host-microbe interactions in salmonids in light of emerging evidence, with an emphasis on intestinal health. In addition, the current understanding of the mode of action of probiotics in salmonid fish is discussed, along with delivery systems that can effectively carry the living microbes.

Phytochemical delivery through nanocarriers: a review

In recent times, phytochemicals encapsulated or conjugated with nanocarriers for delivery to the specific sites have gained considerable research interest. Phytochemicals are mostly plant secondary metabolites which reported to be beneficial for human health and in disease theraphy. However, these compound are large size and polar nature of these compounds, make it difficult to cross the blood-brain barrier (BBB), endothelial lining of blood vessels, gastrointestinal tract and mucosa. Moreover, they are enzymatically degraded in the gastrointestinal tract. Therefore, encapsulation or conjugation of these compounds with nanocrriers could be an alternate way to enhance their bioefficacy by influencing their gastrointestinal stability, rate of absorption and dispersion. This review presents an overview of nanocarriers alternatives which improves therapeutic value and avoid toxicity, by releasing bioactive compounds specifically at target tissues with enhanced stability and bioavailability. Future investigations may emphasize on deciphering the structural changes in nanocarriers during digestion and absorption, the difference between in-vitro and in-vivo digestion simulations, and impact of nanocarriers on the metabolism of phytochemicals.

Soymilk fermentation: effect of cooling protocol on cell viability during storage and in vitro gastrointestinal stress

This work covers soymilk fermentation by starter and probiotic cultures and explores the influence of cooling protocol on cell viability, organic acid production, sugar consumption, fatty acid profile, and cell survival to in vitro gastrointestinal stress. After fermentation at 37 °C by mono- or co-cultures of Streptococcus thermophilus (St), Lactobacillus bulgaricus (Lb), and Lactobacillus paracasei (Lp), fermented soymilk was cooled directly at 4 °C for 28 days or cooled in two phases (TPC), i.e., by preceding that step by another at 25 °C for 8 h. Soybean milk fermentation by Lb alone lasted longer (15 h) than by StLb or StLbLp (9 h). In ternary culture, TPC increased Lp viability, linoleic, and lactic acid concentrations by 3.8, 22.6, and 96.2%, respectively, whereas the cooling protocol did not influence Lp and St counts after in vitro gastrointestinal stress. Graphical abstract.

The Microbiome in Health and Disease from the Perspective of Modern Medicine and Ayurveda

The role of the microbiome in health and disease helps to provide a scientific understanding of key concepts in Ayurveda. We now recognize that virtually every aspect of our physiology and health is influenced by the collection of microorganisms that live in various parts of our body, especially the gut microbiome. There are many external factors which influence the composition of the gut microbiome but one of the most important is diet and digestion. Ayurveda and other systems of traditional health have for thousands of years focused on diet and digestion. Recent research has helped us understand the connection between the microbiome and the many different prevention and therapeutic treatment approaches of Ayurveda.

Effect of different biopolymer-based structured systems on the survival of probiotic strains during storage and in vitro digestion

BACKGROUND

This study aimed to evaluate the protective effect of different biopolymer systems on the viability of two probiotics (Lactobacillus rhamnosus and Streptococcus thermophilus) during storage and in vitro digestion. Methylcellulose (MC), sodium alginate (SA), and whey protein (WP)-based structures were designed and characterized in terms of pH, rheological properties, and visual appearance.

RESULTS

The results highlighted that the WP-system ensured probiotic protection during both storage and in vitro digestion. This result was attributed to a combined effect of the physical barrier offered by the protein gel network and whey proteins as a nutrient for microbes. On the other hand, surprisingly, the viscous methylcellulose-based system was able to guarantee good microbial viability during storage. However, this was not confirmed during in vitro digestion. The opposite results were obtained for sodium alginate beads.

CONCLUSION

The results suggest that the capacity of a polymeric structure to protect probiotic bacteria is a combination of structural organization and system formulation. © 2020 Society of Chemical Industry.

Nanoparticles and Controlled Delivery for Bioactive Compounds: Outlining Challenges for New "Smart-Foods" for Health

Nanotechnology is a field of research that has been stressed as a very valuable approach for the prevention and treatment of different human health disorders. This has been stressed as a delivery system for the therapeutic fight against an array of pathophysiological situations. Actually, industry has applied this technology in the search for new oral delivery alternatives obtained upon the modification of the solubility properties of bioactive compounds. Significant works have been made in the last years for testing the input that nanomaterials and nanoparticles provide for an array of pathophysiological situations. In this frame, this review addresses general questions concerning the extent to which nanoparticles offer alternatives that improve therapeutic value, while avoid toxicity, by releasing bioactive compounds specifically to target tissues affected by specific chemical and pathophysiological settings. In this regard, to date, the contribution of nanoparticles to protect encapsulated bioactive compounds from degradation as a result of gastrointestinal digestion and cellular metabolism, to enable their release in a controlled manner, enhancing biodistribution of bioactive compounds, and to allow them to target those tissues affected by biological disturbances has been demonstrated.

Valorization of okara oil for the encapsulation of Lactobacillus plantarum

Oil-in-water (O/W) emulsions of okara oil-caseinate (1:2; 1:3 and 1:4 O/W ratios) were used to encapsulate Lactobacillus plantarum CIDCA 83114. Once encapsulated, microorganisms were freeze-dried or spray-dried, and observed by scanning electronic and confocal microscopies. A physical characterization of the dehydrated capsules was carried out by determining their moisture content, water activity, particle size, polydispersity index and zeta potential. Determining the induction times and peroxide values provided information about their susceptibility to oxidation. In turn, bacterial stability was analyzed by plate counting before and after freeze-drying and spray-drying, and during storage at 4°C. Spray-dried emulsions had lower Z-sizes and polydispersity indexes, higher induction times and lower peroxide values than the freeze-dried ones, thus resulting better systems to protect L. plantarum CIDCA 83114. In addition, the culturability of spray-dried bacteria did not decrease neither after spray-drying nor up to 60days of storage at 4°C. The results showed that the better physical-chemical stability of spray-dried capsules determined the greater stability of microorganisms. This demonstrates the importance of defining adequate emulsions' formulations for an efficient encapsulation of microorganisms, with promising applications in the development of novel functional foods.

Preparation and characterization of alginate and gelatin microcapsules containing Lactobacillus rhamnosus

This paper describes the preparation and characterization of alginate beads coated with gelatin and containing Lactobacillus rhamnosus. Capsules were obtained by extrusion method using CaCl2 as cross linker. An experimental design was performed using alginate and gelatin concentrations as the variables investigated, while the response variable was the concentration of viable cells. Beads were characterized in terms of size, morphology, scanning electron microscopy (SEM), moisture content, Fourier Transform Infrared Spectrometry (FTIR), thermal behavior and cell viability during storage. The results showed that the highest concentration of viable cells (4.2 x 109 CFU/g) was obtained for 1 % w/v of alginate and 0.1 % w/v of gelatin. Capsules were predominantly spherical with a rough surface, a narrow size distribution ranging from 1.53 to 1.90 mm and a moisture content of 97.70 ± 0.03 %. Furthermore, FTIR and thermogravimetric analysis indicated an interaction between alginate-gelatin. Cell concentration of alginate/gelatin microcapsules was 105 CFU/g after 4 months of storage at 8 oC.

The characteristics and potential applications of structural lipid droplet proteins in plants

Plant cytosolic lipid droplets are storage organelles that accumulate hydrophobic molecules. They are found in many tissues and their general structure includes an outer lipid monolayer with integral and associated proteins surrounding a hydrophobic core. Two distinct types can be distinguished, which we define here as oleosin-based lipid droplets (OLDs) and non-oleosin-based lipid droplets (NOLDs). OLDs are the best characterized lipid droplets in plants. They are primarily restricted to seeds and other germinative tissues, their surface is covered with oleosin-family proteins to maintain stability, they store triacylglycerols (TAGs) and they are used as a source of energy (and possibly signaling molecules) during the germination of seeds and pollen. Less is known about NOLDs. They are more abundant than OLDs and are distributed in many tissues, they accumulate not only TAGs but also other hydrophobic molecules such as natural rubber, and the structural proteins that stabilize them are unrelated to oleosins. In many species these proteins are members of the rubber elongation factor superfamily. NOLDs are not typically used for energy storage but instead accumulate hydrophobic compounds required for environmental interactions such as pathogen defense. There are many potential applications of NOLDs including the engineering of lipid production in plants and the generation of artificial oil bodies.

Probiotic technological and functional characteristics of Lactobacillus strains isolated from chicken gut

Lactobacillus spp. isolated from different portions of chickens' gastrointestinal tract were evaluated concerning their ability to survive in a water-in-oil (W/0) emulsion containing sesame and sunflower oil. After sixty days of emulsion storage under refrigeration, three of five strains tested survived in number equal to or higher than 10(6)cfu/g. Lactobacillus reuteri 2M14C, which presented the highest survival in W/O emulsion (10(7)cfu/g), was tested for its capacity to resist throughout the passage through gnotobiotic mice gastrointestinal tract and for the ability to stimulate murine peritoneal macrophages phagocytosis. This strain remained at a number above 10(9)cfu/g feces during ten days of monoassociation, and monoassociated mice showed phagocytic activity significantly greater than the germ-free controls (P<0.05). The results suggest that the formulation can be used to incorporate viable Lactobacillus spp. cells in animal feed. Moreover, the results suggest that L. reuteri 2M14C is a strong candidate to be incorporated in probiotic formulations for use in chicken.

A review of the advancements in probiotic delivery: Conventional vs. non-conventional formulations for intestinal flora supplementation

Probiotic delivery systems are widely used nutraceutical products for the supplementation of natural intestinal flora. These delivery systems vary greatly in effectiveness to exert health benefits for a patient. Probiotic delivery systems can be categorized into conventional, pharmaceutical formulations, and non-conventional, mainly commercial food-based, products. The degree of health benefits provided by these probiotic formulations varies in their ability to deliver viable, functional bacteria in large enough numbers (effectiveness), to provide protection against the harsh effects of the gastric environment and intestinal bile (in vivo protection), and to survive formulation processes (viability). This review discusses the effectiveness of these probiotic delivery systems to deliver viable functional bacteria focusing on the ability to protect the encapsulated probiotics during formulation process as well as against harsh physiological conditions through formulation enhancements using coatings and polymer enhancements. A brief overview on the health benefits of probiotics, current formulation, patient and legal issues facing probiotic delivery, and possible recommendations for the enhanced delivery of probiotic bacteria are also provided. Newer advanced in vitro analyses that can accurately determine the effectiveness of a probiotic formulation are also discussed with an ideal probiotic delivery system hypothesized through a combination of the two probiotic delivery systems described.

Development of microencapsulation delivery system for long-term preservation of probiotics as biotherapeutics agent

The administration of probiotic bacteria for health benefit has rapidly expanded in recent years, with a global market worth $32.6 billion predicted by 2014. The oral administration of most of the probiotics results in the lack of ability to survive in a high proportion of the harsh conditions of acidity and bile concentration commonly encountered in the gastrointestinal tract of humans. Providing probiotic living cells with a physical barrier against adverse environmental conditions is therefore an approach currently receiving considerable interest. Probiotic encapsulation technology has the potential to protect microorganisms and to deliver them into the gut. However, there are still many challenges to overcome with respect to the microencapsulation process and the conditions prevailing in the gut. This review focuses mainly on the methodological approach of probiotic encapsulation including biomaterials selection and choice of appropriate technology in detailed manner.

Integral Proteins in Plant Oil Bodies

Hydrophobic storage neutral lipids are stably preserved in specialized organelles termed oil bodies in the aqueous cytosolic compartment of plant cells via encapsulation with surfactant molecules including phospholipids and integral proteins. To date, three classes of integral proteins, termed oleosin, caleosin, and steroleosin, have been identified in oil bodies of angiosperm seeds. Proposed structures, targeting traffic routes, and biological functions of these three integral oil-body proteins were summarized and discussed. In the viewpoint of evolution, isoforms of oleosin and caleosin are found in oil bodies of pollens as well as those of more primitive species; moreover, caleosin- and steroleosin-like proteins are also present in other subcellular locations besides oil bodies. Technically, artificial oil bodies of structural stability similar to native ones were successfully constituted and seemed to serve as a useful tool for both basic research studies and biotechnological applications.

Seed oil bodies from Gevuina avellana and Madia sativa

In this study, oil bodies (OBs) from Gevuina avellana (OBs-G) and Madia sativa (OBs-M) were isolated and characterized. Microscopic inspection revealed that the monolayer on OB-G was thinner compared to that on OB-M. Cytometric profiles regarding size, complexity, and staining for the two OB sources were similar. Fatty acid to protein mass ratio in both OBs was near 29, indicating high lipid enrichment. OBs-G and OBs-M showed a strong electrostatic repulsion over wide ranges of pH (5.5-9.5) and NaCl concentration (0-150 mM). Proteins displaying highly conserved sequences (steroleosins and aquaporins) in the plant kingdom were identified. The presence of oleosins was immunologically revealed using antibodies raised against Arabidopsis thaliana oleosins. OBs-G and OBs-M exhibited no significant cytotoxicity against the cells. This is the first report about the isolation and characterization of OBs-G and OBs-M, and this knowledge could be used for novel applications of these raw materials.

The use of hollow fiber membranes combined with cytometry in analysis of bacteriological samples

To avoid destruction of the implanted biological material it may be separated from host immunological system by enclosure within a permiselective membrane. Two-directional diffusion through the membrane of nutrients, metabolic products, as well as bioactive products of encapsulated cells is required to ensure their survival and functional activities. The system of cells encapsulated within the membrane releasing the biologically active substance may be applied either locally to give an opportunity of therapeutic agent activity in the specified place and/or at some convenient site (tissue) for a prolonged period of time.The novel system of bacteria bio-encapsulation using modified membranes, and its assessment by flow cytometry is described and discussed. The encapsulated in membrane bacteria, functioning and releasing their products were evaluated in the systems in vitro and in vivo. The bacteria cells products impact on Eukariotic cells was evaluated. The cytometric evaluation demonstrates the membrane ability to avoid the release of bacteria enclosed within the membrane wall. In experiments with treatment of the bacteria with antibiotic to release products from damaged bacteria it was possible to distinguish stages of the applied antibiotic impact on encapsulated bacteria cells. In E. coli following stages were distinguished: induction of membrane permeability to PI, activation of proteases targeting GFP (protein) and subsequent nucleic acids degradation. In the another experiment the evidence was presented of the cytotoxic activity of live Bacillus subtilis encapsulated within the membrane system. The Bacilus products mediated by secreted listeriolysin O (LLO) on the chosen eukaryotic cells was evaluated. Similar systems releasing bacterial products locally and continuously may selectively affect different types of cells and may have possible application in the anticancer treatment at localized sites.

Selective internalization of self-assembled artificial oil bodies by HER2/neu-positive cells

A novel delivery carrier was developed using artificial oil bodies (AOBs). Plant seed oil bodies (OBs) consist of a triacylglycerol matrix surrounded by a monolayer of phospholipids embedded with the storage protein oleosin (Ole). Ole consists of a central hydrophobic domain with two amphiphatic arms that extrude from the surface of OBs. In this study, a bivalent anti-HER2/neu affibody domain (ZH2) was fused with Ole at the C terminus. After overproduction in Escherichia coli, the fusion protein (Ole-ZH2) was recovered to assemble AOBs. The size of self-assembled AOBs was tailored by varying the oil/Ole-ZH2 ratio and pH to reach a nanoscale. Upon co-incubation with tumor cells, the nanoscale AOBs encapsulated with a hydrophobic fluorescence dye were selectively internalized by HER2/neu-overexpressing cells and displayed biocompatibility with the cells. In addition, the ZH2-mediated endosomal entry of AOBs occurred in a time- and AOB dose-dependent manner. The internalization efficiency was as high as 90%. The internalized AOBs disintegrated at the non-permissive pH (e.g. in acidic endosomes) and the cargo dye was released. Results of in vitro study revealed a sustained and prolonged release profile. Taken together, our findings indicate the potential of AOBs as a delivery carrier.

Selective delivery of cargo entities to tumor cells by nanoscale artificial oil bodies

Artificial oil bodies (AOBs) are oil droplets that result from self-assembly of a mixture containing triacylglycerols, phospholipids, and membrane proteins of plant seeds. Owing to their small size, stability, hydrophobic core, biocompatibility, and biodegradability, AOBs were explored to examine their feasibility as a drug delivery carrier. This was approached by fusion sesame oleosin (Ole), the primary membrane protein of seed oil bodies, with a small domain consisting of the arginine-glycine-aspartic acid (RGD) motif. The resulting Ole-RGD fusion protein was overproduced in Escherichia coli and then isolated for reconstitution of AOBs. At the optimal condition, the size of stable AOBs was within the range of 100-400 nm. Furthermore, AOBs entrapped with a hydrophobic fluorescence dye were incubated with human tumor cells. As visualized by fluorescent microscopy and confocal microscopy, the RGD-tagged AOBs were able to selectively target cells expressing the αvβ3 integrin. Moreover, these AOBs were effectively internalized and the fluorescence dye that they carried was subsequently released inside the cells. The percentage of cells internalized by AOBs could reach 80% as analyzed by flow cytometry. Taken together, it illustrates a great promise of this proposed approach for targeted delivery of cargo entities to tumor cells.

Elevation of oil body integrity and emulsion stability by polyoleosins, multiple oleosin units joined in tandem head-to-tail fusions

We have successfully created polyoleosins by joining multiple oleosin units in tandem head-to-tail fusions. Constructs encoding recombinant proteins of 1, 3 and 6 oleosin repeats were purposely expressed both in planta and in Escherichia coli. Recombinant polyoleosins accumulated in the seed oil bodies of transgenic plants and in the inclusion bodies of E. coli. Although polyoleosin was estimated to only accumulate to <2% of the total oil body protein in planta, their presence increased the freezing tolerance of imbibed seeds as well as emulsion stability and structural integrity of purified oil bodies; these increases were greater with increasing oleosin repeat number. Interestingly, the hexameric form of polyoleosin also led to an observable delay in germination which could be overcome with the addition of external sucrose. Prokaryotically produced polyoleosin was purified and used to generate artificial oil bodies and the increase in structural integrity of artificial oil bodies-containing polyoleosin was found to mimic those produced in planta. We describe here the construction of polyoleosins, their purification from E. coli, and properties imparted on seeds as well as native and artificial oil bodies. A putative mechanism to account for these properties is also proposed.

Elevating Bioavailability of Cyclosporine A via Encapsulation in Artificial Oil Bodies Stabilized by Caleosin

To elevate its bioavailability via oral administration, cyclosporine A (CsA), a hydrophobic drug, was either incorporated into olive oil directly or encapsulated in artificial oil bodies (AOBs) constituted with olive oil and phospholipid in the presence or absence of recombinant caleosin purified from Escherichia coli. The bioavailabilities of CsA in these formulations were assessed in Wistar rats in comparison with the commercial formulation, Sandimmun Neoral. Among these tests, CsA-loaded AOBs stabilized by the recombinant caleosin exhibited better bioavailability than the commercial formulation and possessed the highest maximum whole blood concentration (C(max)), 1247.4 +/- 106.8 ng/mL, in the experimental animals 4.3 +/- 0.7 h (t(max)) after oral administration. C(max) and the area under the plasma concentration-time curve (AUC(0-24)) were individually increased by 50.8% and 71.3% in the rats fed with caleosin-stabilized AOBs when compared with those fed with the reference Sandimmun Neoral. The results suggest that constitution of AOBs stabilized by caleosin may be a suitable technique to encapsulate hydrophobic drugs for oral administration.