Biotechnological application of Aureobasidium spp. as a promising chassis for biosynthesis of ornithine-urea cycle-derived bioproducts.

The ornithine-urea cycle (OUC) in fungal cells has biotechnological importance and many physiological functions and is closely related to the acetyl glutamate cycle (AGC). Fumarate can be released from argininosuccinate under the catalysis of argininosuccinate lyase in OUC which is regulated by the Ca2+ signaling pathway and over 93.9 ± 0.8 g/L fumarate can be yielded by the engineered strain of Aureobasidium pullulans var. aubasidani in the presence of CaCO3. Furthermore, 2.1 ± 0.02 mg of L-ornithine (L-Orn)/mg of the protein also can be synthesized via OUC by the engineered strains of Aureobasidum melanogenum. Fumarate can be transformed into many drugs and amino acids and L-Orn can be converted into siderophores (1.7 g/L), putrescine (33.4 g/L) and L-piperazic acid (L-Piz) (3.0 g/L), by different recombinant strains of A. melanogenum. All the fumarate, L-Orn, siderophore, putrescine and L-Piz have many applications. As the yeast-like fungi and the promising chassis, Aureobasidium spp, have many advantages over any other fungal strains. Further genetic manipulation and bioengineering will enhance the biosynthesis of fumarate and L-Orn and their derivates.

OUC in fungal cells has biotechnological importance and many physiological functions; OUC is closely related to acetyl glutamate cycle (AGC). Fumarate, L-Orn, siderophore, putrescine and L-Piz produced from OUC have many applications.

Chitosan/ß-glycerophosphate porous microsphere prepared by facile water-in-water emulsion as a topical hemostatic material.

Acute hemorrhage is a major cause of death in many emergency cases. Although many hemostatic materials have been studied in recent years, it is still necessary to develop new hemostatic materials with remarkable efficiency, biosafety, convenient preparation, low cost, and good biodegradability. In this work, novel chitosan (CS)/ß-glycerophosphate (ß-GP) composite porous microsphere with a uniform size of 210.00 ± 2.14 µm was fabricated through water-in-water (W/W) emulsion via microencapsulation, which can avoid the use of toxic crosslink chemicals and organic solvents to achieve facile and efficient preparation of microspheres. ß-GP could promote the formation of microspheres by enhancing the hydrogen-bonding interaction between CS chains, which contributed to the macro-porous structure. Owing to their large pore size (6.0 µm) and high specific surface area (37.8 m2/g), the CS/ß-GP microspheres could absorb water quickly and adsorb protein, red blood cells, and platelets through electrostatic forces to promote blood coagulation. Furthermore, the CS/ß-GP microspheres achieved a significantly shortened hemostatic time (45 s) and reduced blood loss (0.03 g) in a rat liver injury model. Rat tail amputation test also showed a satisfactory hemostatic effect. Overall, the green and porous CS/ß-GP microspheres can be used as a facile and topical rapid hemostatic material.

A novel photoelectrochemical self-screening aptamer biosensor based on CAU-17-derived Bi2WO6/Bi2S3 for rapid detection of quorum sensing signal molecules.

Quorum sensing signal molecule is an important biomarker released by some microorganisms, which can regulate the adhesion and aggregation of marine microorganisms on the surface of engineering facilities. Thus, it is significant to exploit a convenient method that can effectively monitor the formation and development of marine biofouling. In this work, an advanced photoelectrochemical (PEC) aptamer biosensing platform was established and firstly applied for the rapid and ultrasensitive determination of N-(3-Oxodecanoyl)-l-homoserine lactone (3-O-C10-HL) released from marine fouling microorganism Ponticoccus sp. PD-2. The visible-light-driven Bi2WO6/Bi2S3 heterojunction derived from metal-organic frameworks (MOFs) CAU-17 and self-screened aptamer were employed as the photoactive materials and bioidentification elements, respectively. Appropriate amount of MoS2 quantum dots (QDs) conjugated with single-stranded DNA were introduced by hybridization to enhance the photocurrent response of the PEC biosensor. The self-screening aptamer can specifically recognize 3-O-C10-HL, accompanied by increasing the steric hindrance and forcing MoS2 QDs to leave the electrode surface, resulting in an obvious reduction of photocurrent and achieving a dual-inhibition signal amplification effect. Under the optimized conditions, the photocurrent response of PEC aptasensor was linear with 3-O-C10-HL concentration from 1 nM to 10 µM, and the detection limit was as low as 0.26 nM. The detection strategy also showed a high reproducibility, superior specificity and good stability. This work not only provides a simple, rapid and ultrasensitive PEC aptamer biosensing strategy for monitoring quorum sensing signal molecules in marine biofouling, but also broadens the application of MOFs-based heterojunctions in PEC sensors.

NsdD, a GATA-type transcription factor is involved in regulation and biosynthesis of macromolecules melanin, pullulan, and polymalate in Aureobasidium melanogenum.

In this study, an NSDD gene, which encoded a GATA-type transcription factor involved in the regulation and biosynthesis of melanin, pullulan, and polymalate (PMA) in Aureobasidium melanogenum, was characterized. After the NSDD gene was completely removed, melanin production by the Δnsd mutants was enhanced, while pullulan and polymalate production was significantly reduced. Transcription levels of the genes involved in melanin biosynthesis were up-regulated while expression levels of the genes responsible for pullulan and PMA biosynthesis were down-regulated in the Δnsdd mutants. In contrast, the complementation of the NSDD gene in the Δnsdd mutants made the overexpressing mutants restore melanin production and transcription levels of the genes responsible for melanin biosynthesis. Inversely, the complementation strains, compared to the wild type strains, showed enhanced pullulan and PMA yields. These results demonstrated that the NsdD was not only a negative regulator for melanin biosynthesis, but also a key positive regulator for pullulan and PMA biosynthesis in A. melanogenum. It was proposed how the same transcriptional factor could play a negative role in melanin biosynthesis and a positive role in pullulan and PMA biosynthesis. This study provided novel insights into the regulatory mechanisms of multiple A. melanogenum metabolites and the possibility for improving its yields of some industrial products through genetic approaches.

Conductive Hyaluronic Acid/Deep Eutectic Solvent Composite Hydrogel as a Wound Dressing for Promoting Skin Burn Healing Under Electrical Stimulation.

Burns can cause severe damage to the skin due to bacterial infection and severe inflammation. Although conductive hydrogels as electroactive burn-wound dressings achieve remarkable effects on accelerating wound healing, issues such as imbalance between their high conductivity and mechanical properties, easy dehydration, and low transparency must be addressed. Herein, a double-network conductive eutectogel is fabricated by integrating polymerizable deep eutectic solvents (PDESs)including acrylamide/choline chloride/glycerol (acrylamide-polymerization crosslink) and thiolated hyaluronic acid (disulfide-bonding crosslink). The introduction of PDESs provides the eutectogel with a conductivity (up to 0.25 S·m-1) and mechanical strength (tensile strain of 59-77%) simulating those of natural human skin, as well as satisfactory tissue adhesiveness, self-healing ability, and antibacterial properties. When combined with exogenous electrical stimulation, the conductive eutectogel exhibits the ability to reduce inflammation, stimulate cell proliferation and migration, promote collagen deposition and angiogenesis, and facilitate skin tissue remodeling. This conductive eutectogel shows great potential as a dressing for healing major burn wounds.

Liamocins overproduction via the two-pH stage fermentation and anti-Aspergillus flavus activity of Massoia lactone.

Aureobasidium melanogenum was found to be grown the best at the constant pH 7.0 and to produce the highest amount of liamocins at the constant pH 3.0. Therefore, the wild type strain A. melanogenum 9-1 and the engineered strain V33 constructed in the laboratory were grown at the constant pH 7.0 for 48 h, then, they were continued to be cultivated at the constant pH 3.0. Under such conditions, A. melanogenum 9-1 produced 36.51 ± 0.55 g L-1 of liamocin and its cell mass was 27.43 ± 0.63 and 6.00 ± 0.11 g L-1 of glucose was left in the finished medium within 168 h while the engineered strain V33 secreted 70.86 ± 2.04 g L-1 of liamocin, its cell mass was 31.63 ± 0.74 g L-1 , 0.16 ± 0.01 g L-1 of glucose was maintained in the finished medium. Then, Massoia lactone was released from the produced liamocins. The released Massoia lactone loaded in the nanoemulsions could be used to actively damage cell wall and cell membrane of both spores and mycelia of Aspergillus flavus, leading to its cell necrosis. Massoia lactone loaded in the nanoemulsions also actively inhibited cell growth of A. flavus, its conidia production and aflatoxin biosynthesis on peanuts, indicating that Massoia lactone loaded in the nanoemulsions had highly potential application in controlling cell growth of A. flavus and aflatoxin biosynthesis in foods and feedstuffs.

Carboxyl-modified nanocellulose (cNC) enhances the stability of cNC/pullulan bio-nanocomposite hard capsule against moisture variation.

The quality of polysaccharide-based films and hard capsules is often affected by changes in relative humidity, manifesting as unstable water content, and changes in mechanical strength that make them brittle or soft. Herein, carboxyl-modified nanocellulose (cNC) was prepared and used as a new component to successfully improve the moisture resistance of cNC/pullulan/high-acyl gellan bio-nanocomposite hard capsules (NCPGs). Homogenously dispersed cNC in the pullulan/high-acyl gellan matrix could render the formation of more hydrogen bonds that provided additional water-binding sites and limited the free movement of pullulan and high-acyl gellan molecular chains within NCPGs. This contributed to a decreased amount of pooling adsorption water and an increased amount of Langmuir adsorption water in NCPGs, as compared to pullulan/high-acyl gellan hard capsules (PGs) without cNC. Therefore, the equilibrium moisture content (EMC) values of NCPGs decreased at 83 % relative humidity and increased at 23 % relative humidity compared to those of PGs. Together with enhanced mechanical and barrier properties, NCPGs effectively protected encapsulated amoxicillin and probiotic powder from changes in the outside humidity. Additionally, NCPGs exhibited faster drug release. This study presents a new mechanism and strategy for fabricating films and hard capsules with enhanced stability against moisture variation.

Liamocin biosynthesis is induced by an autogenous host acid activation in Aureobasidium melanogenum.

It has been known that maximal liamocin production must be carried out at low environmental pH (around 3.0). In this study, it was found that the low pH was mainly caused by the secreted citric acid which is one precursor of acetyl-CoA for liamocin biosynthesis. Determination of citric acid in the culture, deletion, complementation and overexpression of the CEXA gene encoding specific citrate exporter demonstrated that the low pH was indeed caused by the secreted citric acid. Deletion, complementation and overexpression of the ACL gene encoding ATP-citric acid lyase and effects of different initial pHs and added citric acid showed that the low pH in the presence of citric acid was suitable for lysis of intracellular citric acid, liamocin production and expression of the PACC gene encoding the pH signaling transcription factor PacC. This meant that the PACC gene was an acid-expression gene. Deletion, complementation and overexpression of the PACC gene indicated that expression of the key gene cluster GAL1-EST1-PKS1 for liamocin biosynthesis was driven by the pH signaling transcription factor PacC and there was weak nitrogen catabolite repression on liamocin biosynthesis at the low pH. That was why liamocin biosynthesis was induced at a low pH in the presence of citric acid. The mechanisms of the enhanced liamocin biosynthesis by the autogenous host acid activation, together with the pH signaling pathway, were proposed.

Enteromorpha Prolifera Polysaccharide-Derived Injectable Hydrogel for Fast Intraoperative Hemostasis and Accelerated Postsurgical Wound Healing Following Tumor Resection.

Intraoperative bleeding and delayed postsurgical wound healing caused by persistent inflammation can increase the risk of tumor recurrence after surgical resection. To address these issues, Enteromorpha prolifera polysaccharide (PEP) with intrinsic potentials for hemostasis and wound healing, is chemically modified into aldehyde-PEP and hydrazine-PEP. Thereby, an injectable double-network hydrogel (OPAB) is developed via forming dual dynamic bonding of acylhydrazone bonds between the decorated aldehyde and hydrazine groups and hydrogen bonds between hydroxyl groups between boric acid and PEP skeletons. The OPAB exhibits controllable shape-adaptive gelation (35.0 s), suitable mechanical properties, nonstimulating self-healing (60 s), good wet tissue adhesion (30.9 kPa), and pH-responsive biodegradability. For in vivo models, owing to these properties, OPAB can achieve rapid hemostasis within 30 s for the liver hemorrhage, and readily loading of curcumin nanoparticles to remarkably accelerate surgical wound closure by alleviating inflammation, re-epithelialization, granulation tissue formation, and collagen deposition. Overall, this multifunctional injectable hydrogel is a promising material that facilitates simultaneous intraoperative hemorrhage and postsurgical wound repair, holding significant potential in the clinical managements of bleeding and surgical wounds for tumor resection.

Marine phospholipid nanoliposomes: A promising therapeutic approach for inflammatory bowel disease: Preparation, safety, and efficacy evaluation.

Promising findings have been emerged from studies utilizing n3 polyunsaturated fatty acids (PUFA) supplementation in animal models of inflammatory bowel disease (IBD). Introduction of marine phospholipids which combine n3 PUFA with phosphatidylcholine in a nanoliposome formulation offers enhanced pharmacological efficacy due to physical stability, improved bioavailability, and specific targeting to inflamed colitis tissues. In the present study, a marine phospholipid-based nanoliposome formulation was developed and optimized, resulting in nanovesicles of approximately 107.7 ± 1.3 nm in size, 0.18 ± 0.01 PDI, and - 32.03 ± 3.16 mV ZP. The nanoliposomes exhibited spherical vesicles with stable properties upon incubation at SGF as shown by the TEM, DLS, and turbidity measurements over 3 h. MPL nanoliposomes were cytocompatible until the concentration of 500 µg/mL as per MTT assay and taken by macrophages through macropinocytosis and caveolae pathways, and demonstrated significant inhibitory activity against reactive oxygen species (ROS) in LPS-stimulated macrophages. They were also shown to be blood-compatible and safe for administration in healthy mice. In a colitis mouse model, the nanoliposomes displayed preferential distribution in the inflamed gut, delaying the onset of colitis when administered prophylactically. These findings highlight the potential of marine phospholipid nanoliposomes as a promising therapeutic approach for managing inflammatory bowel disease.

The Pathogenic Yeast Metschnikowia bicuspidata var. bicuspidata in the Aquacultured Ecosystem and Its Biocontrol.

M. bicuspidata var. bicuspidata is a pathogenic yeast which can affect aquacultured and marine-cultured animals such as brine shrimp, ridgetail white prawn, chinook salmon, giant freshwater prawn, the Chinese mitten crab, marine crab, the mud crab, the mangrove land crab, the Chinese grass shrimp, sea urchins, sea urchins, Daphnia dentifera and even snails, causing a milky disease, and it has caused big economic losses in aquacultural and marine-cultural industries in the past. However, the detailed mechanisms and the reasons for the milky disease in the diseased aquatic animals are still completely unknown. So far, only some antimycotics, killer toxins and Massoia lactone haven been found to be able to actively control and kill its growth. The ecofriendly, green and renewable killer toxins and Massoia lactone have high potential for application in controlling the milky disease.

Novel chromosomes and genomes provide new insights into evolution and adaptation of the whole genome duplicated yeast-like fungus TN3-1 isolated from natural honey.

Aureobasidium melanogenum TN3-1 strain and A. melanogenum P16 strain were isolated from the natural honey and the mangrove ecosystem, respectively. The former can produce much higher pullulan from high concentration of glucose than the latter. In order to know what happened to their genomes, the PacBio sequencing and Hi-C technologies were used to create the first high-quality chromosome-level reference genome assembly of A. melanogenum TN3-1 (51.61 Mb) and A. melanogenum P16 (25.82 Mb) with the contig N50 of 2.19 Mb and 2.26 Mb, respectively. Based on the Hi-C results, a total of 93.33% contigs in the TN3-1 strain and 92.31% contigs in the P16 strain were anchored onto 24 and 12 haploid chromosomes, respectively. The genomes of the TN3-1 strain had two subgenomes A and B. Synteny analysis showed that the genomic contents of the two subgenomes were asymmetric with many structural variations. Intriguingly, the TN3-1 strain was revealed as a recent hybrid/fusion between the ancestor of A. melanogenum CBS105.22/CBS110374 and the ancestor of another unidentified strain of A. melanogenum similar to P16 strain. We estimated that the two ancient progenitors diverged around 18.38 Mya and merged around 10.66-9.98 Mya. It was found that in the TN3-1 strain, telomeres of each chromosome contained high level of long interspersed nuclear elements (LINEs), but had low level of the telomerase encoding gene. Meanwhile, there were high level of transposable elements (TEs) inserted in the chromosomes of the TN3-1 strain. In addition, the positively selected genes of the TN3-1 strain were mainly enriched in the metabolic processes related to harsh environmental adaptability. Most of the stress-related genes were found to be related to the adjacent LTRs, and the glucose derepression was caused by the mutation of the Glc7-2 in the Snf-Mig1 system. All of these could contribute to its genetic instability, genome evolution, high stress resistance, and high pullulan production from glucose.

The dCache Domain of the Chemoreceptor Tlp1 in Campylobacter jejuni Binds and Triggers Chemotaxis toward Formate.

Chemotaxis is an important virulence factor in some enteric pathogens, and it is involved in the pathogenesis and colonization of the host. However, there is limited knowledge regarding the environmental signals that promote chemotactic behavior and the sensing of these signals by chemoreceptors. To date, there is no information on the ligand molecule that directly binds to and is sensed by Campylobacter jejuni Tlp1, which is a chemoreceptor with a dCache-type ligand-binding domain (LBD). dCache (double Calcium channels and chemotaxis receptor) is the largest group of sensory domains in bacteria, but the dCache-type chemoreceptor that directly binds to formate has not yet been discovered. In this study, formate was identified as a direct-binding ligand of C. jejuni Tlp1 with high sensing specificity. We used the strategy of constructing a functional hybrid receptor of C. jejuni Tlp1 and the Escherichia coli chemoreceptor Tar to screen for the potential ligand of Tlp1, with the binding of formate to Tlp1-LBD being verified using isothermal titration calorimetry. Molecular docking and experimental analyses indicated that formate binds to the membrane-proximal pocket of the dCache subdomain. Chemotaxis assays demonstrated that formate elicits robust attractant responses of the C. jejuni strain NCTC 11168, specifically via Tlp1. The chemoattraction effect of formate via Tlp1 promoted the growth of C. jejuni, especially when competing with Tlp1- or CheY-knockout strains. Our study reveals the molecular mechanisms by which C. jejuni mediates chemotaxis toward formate, and, to our knowledge, is the first report on the high-specificity binding of the dCache-type chemoreceptor to formate as well as the physiological role of chemotaxis toward formate. IMPORTANCE Chemotaxis is important for Campylobacter jejuni to colonize favorable niches in the gastrointestinal tract of its host. However, there is still a lack of knowledge about the ligand molecules for C. jejuni chemoreceptors. The dCache-type chemoreceptor, namely, Tlp1, is the most conserved chemoreceptor in C. jejuni strains; however, the direct-binding ligand(s) triggering chemotaxis has not yet been discovered. In the present study, we found that the ligand that binds directly to Tlp1-LBD with high specificity is formate. C. jejuni exhibits robust chemoattraction toward formate, primarily via Tlp1. Tlp1 is the first reported dCache-type chemoreceptor that specifically binds formate and triggers strong chemotaxis. We further demonstrated that the formate-mediated promotion of C. jejuni growth is correlated with Tlp1-mediated chemotaxis toward formate. Our work provides important insights into the mechanism and physiological function of chemotaxis toward formate and will facilitate further investigations into the involvement of microbial chemotaxis in pathogen-host interactions.

Bioconversion of non-food corn biomass to polyol esters of fatty acid and single-cell oils.

BACKGROUND: Lignocellulose is a valuable carbon source for the production of biofuels and biochemicals, thus having the potential to substitute fossil resources. Consolidated bio-saccharification (CBS) is a whole-cell-based catalytic technology previously developed to produce fermentable sugars from lignocellulosic agricultural wastes. The deep-sea yeast strain Rhodotorula paludigena P4R5 can produce extracellular polyol esters of fatty acids (PEFA) and intracellular single-cell oils (SCO) simultaneously. Therefore, the integration of CBS and P4R5 fermentation processes would achieve high-value-added conversion of lignocellulosic biomass. RESULTS: The strain P4R5 could co-utilize glucose and xylose, the main monosaccharides from lignocellulose, and also use fructose and arabinose for PEFA and SCO production at high levels. By regulating the sugar metabolism pathways for different monosaccharides, the strain could produce PEFA with a single type of polyol head. The potential use of PEFA as functional micelles was also determined. Most importantly, when sugar-rich CBS hydrolysates derived from corn stover or corncob residues were used to replace grain-derived pure sugars for P4R5 fermentation, similar PEFA and SCO productions were obtained, indicating the robust conversion of non-food corn plant wastes to high-value-added glycolipids and lipids. Since the produced PEFA could be easily collected from the culture via short-time standing, we further developed a semi-continuous process for PEFA production from corncob residue-derived CBS hydrolysate, and the PEFA titer and productivity were enhanced up to 41.1 g/L and 8.22 g/L/day, respectively. CONCLUSIONS: Here, we integrated the CBS process and the P4R5 fermentation for the robust production of high-value-added PEFA and SCO from non-food corn plant wastes. Therefore, this study suggests a feasible way for lignocellulosic agro-waste utilization and the potential application of P4R5 in industrial PEFA production.

The ornithine-urea cycle involves fumaric acid biosynthesis in Aureobasidium pullulans var. aubasidani, a green and eco-friendly process for fumaric acid production.

The current petroleum chemical methods for fumaric acid production can cause heavy pollution and global warming. In this study, the engineered strains of A. pullulans var. aubasidani were found to be suitable for green fumaric acid producer. Removal and complementation of the relevant genes showed only the ornithine-urea cycle (OUC) was involved in high level fumarate biosynthesis which was controlled by the Ca2+ signaling pathway. Removal of both the GOX gene encoding glucose oxidase and the PKS1 gene encoding the polyketide synthase for 3,5-dihydroxydecanoic acid biosynthesis and overexpression of the PYC gene encoding pyruvate carboxylase made the strain e-PYC produce 88.1 ± 4.3 g/L of fumarate at flask level and 93.9 ± 0.8 g/L of fumarate during the fed-batch fermentation. As a yeast-like fungal strain, it was very easy to cultivate A. pullulans var. aubasidani DH177 and their mutants in the bioreactor and to edit its genomic DNAs to enhance fumarate production. It was found that 2 mol of CO2 could be fixed during a maximal theoretical yield of 2 mol of fumarate per mole of glucose consumed in the OUC. Therefore, the OUC-mediated fumarate biosynthesis pathway in A. pullulans var. aubasidani was a green and eco-friendly process for the global sustainable development and carbon neutrality.

Genome-Wide Editing Provides Insights into Role of Unsaturated fatty Acids in Low Temperature Growth of the Psychrotrophic Yeast Metschnikowia bicuspidata var. australis W7-5.

In order to know the function of C18:2 and C18:3 fatty acids in the cold growth of the psychrotrophic yeast M. bicuspidata var. australis W7-5, the mutant 1 without C18:2 fatty acid and the mutant 2 without C18:3 fatty acids were obtained. Only the trace amount of C18:2 fatty acid in the mutant 1 occurred while no C18:3 fatty acid in the mutant 2 was detected. The growth rate of only the mutant 1 cultured at 5 â„ƒ and 25 â„ƒ was significantly reduced compared with that of the wild-type strain W7-5. But there was no difference between the growth of the mutant 2 and that of the W7-5 strain. These meant that only C18:2 synthesized by the psychrotrophic yeast played an important role in cell growth at low temperature (5 °C) and high temperature (25 °C). Meanwhile, cell wall in the mutant 1 without C18:2 fatty acid gown at 5 and 25 °C was also negatively affected, leading to the reduced cell growth rate of the mutant 1 grown at 5 and 25 °C.

Metabolic engineering of Aureobasidium melanogenum 9-1 for overproduction of liamocins by enhancing supply of acetyl-CoA and ATP.

In this study, it was found that reducing consumption of acetyl-CoA in mitochondria, peroxisome and lipid biosynthesis could not obviously enhance liamocin biosynthesis by engineered strains of Aureobasidium melanogenm 9-1, but decreased cell growth of the mutants. On the contrary, expression of heterologous PTA gene for phosphotransacetylase in PK pathway and native ALD gene for acetaldehyde dehydrogenase and ACS gene encoding acetyl-CoA synthetase in the PDH bypass pathway reduced liamocin biosynthesis. However, expression the PK gene for phosphoketolase, the PDC gene encoding pyruvate decarboxylase and VHb gene coding for Vitreoscilla hemoglobin (VHb) in the glucose derepression mutants could greatly enhance liamocin production. The resulting strain V33 could produce 55.38 g/L of liamocin and 25.10 g/L of cell dry weight from 117.27 g/L of glucose within 168 h of 10-liter fermentation, leading to the yield of 0.47 g/g of glucose, the productivity of 0.33 g/L/h and rate of glucose utilization of 0.70 ± 0.01 g/L/h. This was a new and efficient strategy for overproduction of liamocin by A. melanogenm.

Multifunctional nanoparticles based on marine polysaccharides for apremilast delivery to inflammatory macrophages: Preparation, targeting ability, and uptake mechanism.

Hydrophobic drug encapsulation inside targeted nanoparticles can enhance accumulation in inflamed sites, limit toxicity to healthy tissue, and improve pharmacokinetics compared to free drug dosing. This study reports a functionalized marine polysaccharide nanoparticle with a controlled release, targeting abilities, and in-situ imaging properties. Carbon dots functionalized Enteromorpha polysaccharide/Mannose/Methionine functionalized Chitosan (CDs.EP/Man/Meth.Cs) NPs could deliver apremilast to inflammatory macrophages and Caco-2 intestinal cells as an in vitro model for application in oral drug delivery to cure IBD. The nanoparticles were simply a polyelectrolyte complex between cationic functionalized chitosan and anionic polysaccharide of Enteromorpha prolifera. Functionalized polysaccharides and the prepared NPs were well characterized. The functionalized nanoparticles could overcome the limitation of poor drug bioavailability and showed a high loading capacity of (45 %) with a controlled release of about (74.5 %). Confocal laser scanning imaging showed higher cellular uptake of the modified nanoparticles than that of the unmodified nanoparticles in LPS-activated RAW 264.7 macrophages and Caco-2 cells. The effect of functionalization on the cellular uptake targetability was assessed using spectrofluorometric measurements after mannose competition. Anti-inflammatory activity of apremilast-loaded NPs is more elevated than the free drug. These results suggest the feasibility of using functionalized EP/Cs nanoparticles in IBD oral drug delivery.

Cosmetic-Derived Mannosylerythritol Lipid-B-Phospholipid Nanoliposome: An Acid-Stabilized Carrier for Efficient Gastromucosal Delivery of Amoxicillin for In Vivo Treatment of Helicobacter pylori.

Helicobacter pylori infection is a leading cause of gastritis and peptic ulcer. Current treatments for H. pylori are limited by the increase in antibiotic-resistant strains and low drug delivery to the infection site, indicating the need for effective delivery systems of antibiotics. Although liposomes are the most successful drug delivery carriers that have already been applied commercially, their acidic stability still stands as a problem. Herein, we developed a novel nanoliposome using cosmetic raw materials of mannosylerythritol lipid-B (MEL-B), soy bean lecithin, and cholesterol, namely, LipoSC-MELB. LipoSC-MELB exhibited enhanced stability under the simulated gastric-acid condition, owing to its strong intermolecular hydrogen-bond interactions caused by the incorporation of MEL-B. Moreover, amoxicillin-loaded LipoSC-MELB (LipoSC-MELB/AMX) had a particle size of approximately 100 nm and exhibited sustained drug release under varying pH conditions (pH 3-7). Besides, LipoSC-MELB/AMX exhibited significantly higher anti-H. pylori and anti-H. pylori biofilm activity as compared with free AMX. Furthermore, LipoSC-MELB was able to carry AMX across the barriers of gastric mucus and H. pylori biofilms. Remarkably, in vivo assays indicated that LipoSC-MELB/AMX was effective in treating H. pylori infection and its associated gastritis and gastric ulcers. Overall, the findings of this study showed that LipoSC-MELB was effective for gastromucosal delivery of amoxicillin to improve its bioavailability for the treatment of H. pylori infection.

Intrinsic specificity of plain ammonium citrate carbon dots for Helicobacter pylori: Interfacial mechanism, diagnostic translation and general revelation.

The exploitation of carbon dots (CDs) is now flourishing; however, more effort is needed to overcome their lack of intrinsic specificity. Herein, instead of synthesizing novel CDs, we reinvestigated three reported CDs and discovered that plain ammonium citrate CDs (AC-CDs) exhibited surprising specificity for Helicobacter pylori. Notably, we showed that the interfacial mechanism behind this specificity was due to the affinity between the high abundant urea/ammonium transporters on H. pylori outer membrane and the surface-coordinated ammonium ions on AC-CDs. Further, we justified that ammonium sulfate-citric acid CDs also possessed H. pylori-specificity owing to their NH4 + doping. Thereby, we suggested that the incorporation of a molecule that could be actively transported by abundant membrane receptors into the precursors of CDs might serve as a basis for developing a plain CD with intrinsic specificity for H. pylori. Moreover, AC-CDs exhibited specificity towards live, dead, and multidrug-resistant H. pylori strains. Based on the specificity, we developed a microfluidics-assisted in vitro sensing approach for H. pylori, achieving a simplified, rapid and ultrasensitive detection with two procedures, shortened time within 45.0 â€‹min and a low actual limit of detection of 10.0 â€‹CFU â€‹mL-1. This work sheds light on the design of more H. pylori-specific or even bacteria-specific CDs and their realistic translation into clinical practice.