Analysis of the process and factors influencing microbial phosphine production.

The process of phosphine production by phosphate-reducing bacteria Pseudescherichia sp. SFM4 has been well studied. Phosphine originates from the biochemical stage of functional bacteria that synthesize pyruvate. Stirring the aggregated bacterial mass and supplying pure hydrogen could lead to an increase of 40 and 44% phosphine production, respectively. Phosphine was produced when bacterial cells agglomerated in the reactor. Extracellular polymeric substances secreted on microbial aggregates promoted the formation of phosphine due to the presence of groups containing phosphorus element. Phosphorus metabolism gene and phosphorus source analysis implied that functional bacteria used anabolic organic phosphorus, especially containing carbon-phosphorus bonds, as a source with [H] as electron donor to produce phosphine.

Facile modification of nanochitin in aqueous media for stabilizing tea tree oil based Pickering emulsion with prolonged antibacterial performance.

Nanochitins have been explored for preparing Pickering Emulsions, however its application is restricted by its simplex disperse nature. It was hypothesized that zwitterionic nanochitins should be capable of stabilizing oil/water (O/W) interfaces in wider pH range. Furthermore, the control of their size, disperse nature and self-assembly performance suggest the formulation of tunable emulsions. Zwitterionic nanochitins were prepared via Schiff base reaction. A systematic study was performed analyzing the disperse nature, fibril morphology, surface characteristic of modified nanochitins. Oil-in-Water Pickering Emulsions stabilized by modified nanochitins were formulated and emulsion stability was analyzed as function of concentration, pH and self-assembly property and further applied for prolonged antibacterial applications. Comparing freshly prepared nanochitins, neutral/alkaline stably dispersed nanochitins can be prepared while maintaining fibril characteristics such as fibril size, crystallinity, thermal stability and so on. Better suspension stability of modified nanochitins under alkaline conditon together with the self assembly performance resulting from amino groups and carboxyl groups benefit the enhanced emulsion stability under nanochitins concentreation of 0.2 %. Encapsulation of tea tree oil in Pickering Emulsions prolongs the diffusion rate oil in the aqueous environment, thus resulting prolongs its antibacterial performance against E. coli and B. subtilis.

Analysis of the characteristics of phosphine production by anaerobic digestion based on microbial community dynamics, metabolic pathways, and isolation of the phosphate-reducing strain.

Although phosphine is ubiquitously present in anaerobic environments, little is known regarding the microbial community dynamics and metabolic pathways associated with phosphine formation in an anaerobic digestion system. This study investigated the production of phosphine in anaerobic digestion, with results indicating that phosphine production mainly occurred during logarithmic microbial growth. Dehydrogenase and hydrogen promoted the production of phosphine, with a maximum phosphine concentration of 300 mg/m3. The abundance of Ruminococcaceae and Escherichia was observed to promote phosphine generation. The analysis of metabolic pathways based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) and the MetaCyc pathway database revealed the highest relative abundance of replication and repair in genetic information processing; further, the cofactor, prosthetic group, electron carrier, and vitamin biosynthesis were observed to be closely related to phosphine formation. A phylogenetic tree was reconstructed based on the neighbor-joining method. The results indicated the clear evolutionary position of the isolated Pseudescherichia sp. SFM4 strain, adjacent to Escherichia, with a stable phosphate-reducing ability for a maximum phosphine concentration of 26 mg/m3. The response surface experiment indicated that the initial optimal conditions for phosphine production by SFM4 could be achieved with nitrogen, carbon, and phosphorus loads of 6.17, 300, and 10 mg/L, respectively, at pH 7.47. These results provide comprehensive insights into the dynamic changes in the microbial structure, isolated single bacterial strain, and metabolic pathways associated with phosphine formation. They also provide information on the molecular biology associated with phosphorus recycling.

Construction of arabinogalactans/selenium nanoparticles composites for enhancement of the antitumor activity.

Selenium nanoparticles (SeNPs) were synthesized using arabinogalactans (LAG) as a formation scaffolding and particle stabilizer to investigate their anti-tumor properties. The formation, morphology, size, and in vitro biological activity of LAG-SeNPs were characterized by UV-vis, FT-IR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and cell toxicity assays. SEM and TEM of LAG-SeNPs visualized the individual spherical nanoparticles, while the spectroscopic characterization revealed the modes of interaction which lead to the stable particle properties of the LAG-SeNPs. Cell toxicity assays indicated that the products had significant inhibitory effect on A549, HepG-2 and MCF-7 cells with a dose-dependent effect. The toxicity mechanisms of LAG-SeNPs were further investigated, and assay results revealed that LAG-SeNPs mainly induced cancer cellular apoptosis to promote atrophy and inhibit cell proliferation. The sum of these findings demonstrates the positive effects that a biomass-derived polysaccharide exert upon non-metal/metalloid-based nanoparticles and the ensuing material's viability as treatment against human cancers.

Upgrading Pectin Production from Apple Pomace by Acetic Acid Extraction.

Pectin, as one of the most widely used functional polysaccharide, can be abundantly extracted from apple pomace which is the main by-product of apple juice industry. In the case of 110 min, 10% (w/w) acetic acid (AA), and 100 °C, extraction yield of pectin reached 19.6%. Compared with mineral acid-extracted pectin, the yield, molecular weight, galacturonic acid content, and DE of the AA-extracted pectin were higher while neutral sugars were lower. Furthermore, the AA-extracted pectin solution demonstrated a higher viscosity during the shear rate increased, and a higher G″ modulus than pectin extracted with mineral acid and commercial pectin possibly because of stronger polymer chain interaction, which was reflected in gel textural properties. The green approach for the pectin production, in terms of pectin components was developed from apple pomace using AA that was highly competitive and environmentally friendly process.

Synthesis and Characterization of an Antioxidative Galactomannan⁻Iron(III) Complex from Sesbania Seed.

Galactomannan, a water-soluble polymer in the cell wall of leguminous plants, has been proven to possess anticancer and antioxidative activity. In this work, galactomannan with different molecular weights (GM-40 and GM-65) was obtained from Sesbania seeds and synthesized into galactomannan⁻iron(III) complexes, which are termed as GM-40-Fe and GM-65-Fe, respectively. These galactomannan⁻iron(III) complexes are intended to function as organic iron supplements to treat iron deficiency with the added benefit of antioxidative activity. The prepared galactomannan⁻iron(III) complexes were characterized for chemical composition, morphology, antioxidant capacity, and bioavailability in vitro. The results showed that galactomannan⁻iron(III) complexes could be produced with iron contents as high as 65.4 mg/g. Antioxidant assays indicated that both GM-40-Fe and GM-65-Fe exhibited antioxidant activities for scavenging radicals in vitro. The iron release/bioavailability assays showed that the iron was easily released into artificial gastric and intestinal juices, resulting in iron release rates of 88⁻94% over 300 min. These results suggest that galactomannan⁻iron(III) complexes synthesized from Sesbania seed polysaccharides are capable of being administered as organic iron supplements to patients with iron deficiency.

Diterpene alkaloids and diterpenes from Spiraea japonica and their anti-tobacco mosaic virus activity.

Five new naturally occurring natural products, including two atisine-type diterpene alkaloids (1 and 2), two atisane-type diterpenes (3 and 4), and a new natural product spiramine C2 (5), along with nine known ones (6-14), were isolated from the ethanolic extracts of the whole plant of Spiraea japonica var. acuminata Franch. Their structures were elucidated by extensive spectroscopic analysis. The anti-tobacco mosaic virus (TMV) activities of all the compounds were evaluated by the conventional half-leaf method. Six compounds (2, 3, 6, 7, 11, and 12) exhibited moderate activities at 100 µg/mL with inhibition rates in the range of 69.4-92.9%, which were higher than that of the positive control, ningnanmycin. Their preliminary structure-activity relationships were also discussed.

Limonoids from Munronia henryi and their anti-tobacco mosaic virus activity.

Five new compounds (1-5), including three limonoids, one diterpenoid, and one phytosterol, along with four known limonoids (6-9), were isolated from the ethanolic extracts of whole plants of Munronia henryi. Their structures were elucidated by extensive spectroscopic analysis. In addition, the anti-tobacco mosaic virus (TMV) activities of all the isolated compounds were evaluated by the conventional half-leaf and leaf-disk methods along with Western blot analysis. Most of the tested compounds showed strong antiviral activities, with IC50 values in the range of 14.8-34.0µg/mL, compared with ningnanmycin as a positive control (IC50=44.6µg/mL), and their preliminary structure-activity relationships were also discussed.

[Study on chemical constituents of Inula cappa].

Column chromatographies over silica gel, Sephadex LH-20, reverse phase C18, and MCI, and semi-preparative HPLC were used for separation and purification of constituents from Inula cappa. The 22 compounds were obtained and their strutures were determined by NMR and MS spectra data as nine flavonoids: luteolin (1), apigenin (2), chrysoeriol (3), artemetin (4), 2', 5-di- hydroxy-3, 6, 7, 4', 5'-pentamethoxyflavone (5), chrysosplenol C (6), apigenin-5-0-ß-D-glucopyranoside (7), luteolin-3-methyl, luteolin-3-methylether-4'-0-ß-D-glucopyranoside (8), luteolin-4'-0-ß-D-glucopyranoside (9); four triterpenes: darma-20, 24-dien- 3ß-0-acetate (10), darma-20, 24-dien-3ß-ol (11), epirfiedelanol (12), friedelin (13); three coumarins: scopoletin (14) , isosco- poletin (15) , scopolin(16) , and other types of compounds stigmasta-5, 22-dien-3ß-0-7-one (17), stigmasterol (18), palmitic acid (19), linoleic acid (20), linoleic acid methyl ester (21), (E) -9, 12, 13-trihydroxyoetadee-10-enoie acid (22). Compound 5 is a new natural product. Compounds 3-9, 15, 17, 21, and 22 were isolated from this genus for the first time.