D-allose, a typical rare sugar: properties, applications, and biosynthetic advances and challenges.

D-allose, a C-3 epimer of D-glucose and an aldose-ketose isomer of D-allulose, exhibits 80% of sucrose's sweetness while being remarkably low in calories and nontoxic, making it an appealing sucrose substitute. Its diverse physiological functions, particularly potent anticancer and antitumor effects, render it a promising candidate for clinical treatment, garnering sustained attention. However, its limited availability in natural sources and the challenges associated with chemical synthesis necessitate exploring biosynthetic strategies to enhance production. This overview encapsulates recent advancements in D-allose's physicochemical properties, physiological functions, applications, and biosynthesis. It also briefly discusses the crucial role of understanding aldoketose isomerase structure and optimizing its performance in D-allose synthesis. Furthermore, it delves into the challenges and future perspectives in D-allose bioproduction. Early efforts focused on identifying and characterizing enzymes responsible for D-allose production, followed by detailed crystal structure analysis to improve performance through molecular modification. Strategies such as enzyme immobilization and implementing multi-enzyme cascade reactions, utilizing more cost-effective feedstocks, were explored. Despite progress, challenges remain, including the lack of efficient high-throughput screening methods for enzyme modification, the need for food-grade expression systems, the establishment of ordered substrate channels in multi-enzyme cascade reactions, and the development of downstream separation and purification processes.

Characterization of l-fucose isomerase from Paenibacillus rhizosphaerae to produce l-fuculose from hydrolyzed fucoidan and commercial fucose.

AIMS: l-Fuculose is a valuable rare sugar that is used to treat a variety of ailments, including HIV, cancer, Hepatitis B, human lysosomal disease (fucosidosis), and cardio-protective medications. The enzymatic approach for the production of l-fuculose using l-fucose as a substrate would be an advantageous method with a wide range of industrial applications. The objective of this study is the characterization of recombinant l-fucose isomerase from Paenibacillus rhizosphaerae (Pa-LFI) for the production of l-fuculose from an inexpensive and natural source (fucoidan) as well as its comparison with commercial l-fucose (Sigma-Aldrich). METHODS AND RESULTS: Fucoidan, a fucose-containing polysaccharide (FPs), was isolated from Undaria pinnatifida, subsequently hydrolyzed, and characterized before the enzymatic production of l-fuculose. The results elaborate that FPs contain 35.9% of fucose along with other kinds of monosaccharides. The purified Pa-LFI exhibited a single band at 65 kDa and showed it as a hexamer with a native molecular mass of 396 kDa. The highest activity of 104.5 U mg-1 of Pa-LFI was perceived at a temperature of 50°C and pH 6.5 in the presence of 1 mM of Mn2+. The Pa-LFI revealed a melting temperature (Tm) of 75°C and a half-life of 12.6 h at 50°C. It exhibited that Pa-LFI with aldose substrate (l-fucose), has a stronger isomerizing activity, disclosing Km,kcat, and kcat/Km 86.2 mM, 32 831 min-1, and 335 min-1 mM-1, respectively. After reaching equilibrium, Pa-LFI efficiently catalyzed the reaction to convert l-fucose into l-fuculose and the conversion ratios of l-fuculose from 100 g L-1 of FPs and commercial fucose were around 6% (5.6 g L-1) and 30% (30.2 g L-1), respectively. CONCLUSIONS: According to the findings of the current study, the Pa-LFI will be useful in the manufacturing of l-fuculose using an effective and easy approach that produces no by-products.

Fucoidan-based nanomaterial and its multifunctional role for pharmaceutical and biomedical applications.

Fucoidans are promising sulfated polysaccharides isolated from marine sources that have piqued the interest of scientists in recent years due to their widespread use as a bioactive substance. Bioactive coatings and films, unsurprisingly, have seized these substances to create novel, culinary, therapeutic, and diagnostic bioactive nanomaterials. The applications of fucoidan and its composite nanomaterials have a wide variety of food as well as pharmacological properties, including anti-oxidative, anti-inflammatory, anti-cancer, anti-thrombic, anti-coagulant, immunoregulatory, and anti-viral properties. Blends of fucoidan with other biopolymers such as chitosan, alginate, curdlan, starch, etc., have shown promising coating and film-forming capabilities. A blending of biopolymers is a recommended approach to improve their anticipated properties. This review focuses on the fundamental knowledge and current development of fucoidan, fucoidan-based composite material for bioactive coatings and films, and their biological properties. In this article, fucoidan-based edible bioactive coatings and films expressed excellent mechanical strength that can prolong the shelf-life of food products and maintain their biodegradability. Additionally, these coatings and films showed numerous applications in the biomedical field and contribute to the economy. We hope this review can deliver the theoretical basis for the development of fucoidan-based bioactive material and films.

Enrichment and balancing of nutrients for improved methane production using three compositionally different agro-livestock wastes: Process performance and microbial community analysis.

Balanced nutrition is important for maximizing anaerobic digestion (AD) performance. Herein, the strategy of balancing sugar-fiber-nitrogen nutrients was first established for improved methane production by co-digesting two agricultural and one livestock wastes with complementary compositional properties, such as banana pseudo-stem (BPS), sugarcane baggage (SCB), and chicken manure (CM) having high sugar, fiber and nitrogen contents, respectively. The maximum methane yield was 186.5 mL/g VSadded with a mixture of 45.7% BPS, 26.2% SCB and 28.1% CM (with 1: 11.3: 0.3 of sugar to fiber to nitrogen ratio), increasing by 16.1%, 53.3%, 122.6% than those of mono- BPS, SCB, and CM, respectively. The co-digestion process remained stable under an organic load of 4 g VS/(L·day), which was attributed to the predominant presence of Bacteroidetes, Proteobacteria, Thauera, uncultured_bacterium_p_Aegiribacteria, and hydrogenotrophic methanogens. This study provides a deeper understanding of the co-digestion with agricultural and livestock wastes from the perspective of nutrient balance.

Novel biocatalytic strategy of levan: His-ELP-intein-tagged protein purification and biomimetic mineralization.

Here a versatile fusion tag composed of His-tag, intein, and elastin-like polypeptide (ELP) tag was prepared for the first time to be fused with levansucrase SacB to construct a recombinant His-ELP-intein-SacB (HEIS) protein to realize nonchromatographic purification of SacB. The efficient biomimetic mineralization of CaHPO4 and HEIS-based hybrid-hydrangea (CaHPO4-HEIS-HH) with good reusability, excellent storage stability and 254.3% improved relative levan yield was prepared with the biomimetic mineralization method. Additionally, the CaHPO4-HEIS-HH showed outstanding operation activity when catalyzing sucrose in solution and up to 75% sucrose conversion rate in fruit juices. The mechanism of biomimetic mineralization was analyzed to show that the HEIS protein might serve as a "binder" to assemble the nanoflakes during biomimetic mineralization. The CaHPO4-HEIS-HH was applicable for efficient production of the levan-type prebiotic polysaccharides, and this approach should be highly valuable for nonchromatographic purification and convenient preparation of various encapsulated enzymes for more efficient catalysis.

Efficient Molecular Biological Manipulations with Improved Strategies Based on Novel Escherichia coli Vectors.

In this study, some novel plasmids have been constructed for flexible and zero-background molecular cloning, more efficient expression, and purification of proteins with improved strategies. The plasmids pANY4-pL18-ccdB and pANY4-pR18/pL18-ccdB have different promoters in the complementary DNA strands. Therefore, recombinant plasmids for either isopropyl-ß-d-thiogalactoside-induced or temperature-induced protein expression could be simultaneously constructed in a single molecular cloning process for parallel comparison. Intriguingly, the mutated pL18 and pR18/pL18 promoters performed similar to or even better than the T7 promoter when used for promoting the expression of the GFP or pfLamA enzyme. Moreover, the plasmid pANY8 containing the His-elastin-like polypeptide (ELP)-intein multifunctional tag was constructed, and special purification protocol was designed to obtain purified proteins without the requirement of time-consuming dialysis steps to remove imidazole and high concentration of salt ions. Additionally, the urea-based denaturation and refolding processes can be conveniently integrated into the ELP-mediated precipitation protocol for purification of insoluble inclusion bodies, omitting the time-consuming dialysis steps.

Pleiotropic Functions and Biological Potentials of Silver Nanoparticles Synthesized by an Endophytic Fungus.

In recent years, the biological synthesis of silver nanoparticles (AgNPs) from microorganisms has become an emerging trend for developing biocompatible nanomaterials that finds applications in nano and biomedical sectors. In the present study, we demonstrated a facile, green and eco-friendly method for AgNPs synthesis using the endophytic fungi (Colletotrichum incarnatum DM16.3) isolated from medicinal plant Datura metel and its in vitro antithrombin and cytotoxic activity. At first, biosynthesis of colloidal AgNPs was predicted by visual observation of color change and UV-visible spectra demonstrated specific surface plasmon resonance peak at 420 nm which confirmed the presence of nanoparticles. Microscopic analyses revealed the structure of highly aggregated, spherical and crystalline AgNPs in the diameter range of 5-25 nm. Transform infrared spectroscopy (FT-IR) spectral analysis confirmed the presence of probable biomolecules required for the reduction of silver ions. In vitro evaluation of thrombin activity demonstrates that AgNPs could exert strong inhibition against both thrombin activity (87%) and thrombin generation (84%), respectively. Further, in silico based mechanistic analysis yielded a better insight in understanding the probable amino acids responsible for AgNPs binding with thrombin protein. Similarly, in vitro cytotoxicity of synthesized AgNPs on human epithelial cells using MTT assay did not produce any substantial effects after 24 h exposure which indicates excellent biocompatibility nature, whereas notable toxicity was observed on human cancerous (HeLa) cells at 50 µg/mL (IC50 value). In addition, assessment of AgNPs at 10 µg/mL concentration via crystal violet method on biofilm forming Gram-positive (Vibrio cholerae) and Gram-negative bacteria (Bacillus cereus) revealed inhibition up to 85 and 46%, respectively. Overall, this study showed the possibility of microbially synthesized AgNPs as a potent inhibitor for managing acute thrombosis and highlighted their role for other biomedical applications.

Research Progress in Reversal of Tumor Multi-drug Resistance via Natural Products.

Multidrug resistance occurs when a tumor develops resistance to multiple chemotherapeutic drugs, which may include antitumor drugs with different chemical structures and mechanisms. Multidrug resistance limits the treatment effects of antitumor drugs, and is the main cause of chemotherapy failure. Multidrug resistance is caused by numerous factors including changes in ATP-binding cassette transporters, target proteins, detoxification, deoxyribonucleic acid repair, drug metabolic enzymes, and signal pathways of apoptosis. Clinical research indicates that natural products have great potential to treat tumors and reverse multidrug resistance. Natural products, which often have multiple targets, could play an important role in tumor treatment, have beneficial effects on tumor inhibition, improve symptoms, reduce radiotherapy and chemotherapy side effects, enhance immunity, and prolong survival. Because natural products often have few adverse reactions and less drug resistance, the antitumor activities of natural products have attracted extensive research. We aimed to review the basic research and clinical application of natural products in the reversal of multidrug resistance.