Lysis is a common functional module in synthetic biology and is widely used in genetic circuit design. Lysis could be achieved by inducing expression of lysis cassettes originated from phages. However, detailed characterization of lysis cassettes hasn't been reported yet. Here, we first adopted arabinose- and rhamnose-inducible systems to develop inducible expression of five lysis cassettes (S₁₀₅, A52G, C51S S76C, LKD, LUZ) in Escherichia coli Top10. By measuring OD₆₀₀, we characterized the lysis behavior of strains harboring different lysis cassettes. These strains were harvested at different growth stages, induced with different concentrations of chemical inducers, or contained plasmids with different copy numbers. We found that although all five lysis cassettes could induce bacterial lysis in Top10, lysis behaviors differed a lot at various conditions. We further found that due to the difference in background expression levels between strain Top10 and Pseudomonas aeruginosa PAO1, it was hard to construct inducible lysis systems in strain PAO1. The lysis cassette controlled by rhamnose-inducible system was finally inserted into the chromosome of strain PAO1 to construct lysis strains after careful screen. The results indicated that LUZ and LKD were more effective in strain PAO1 than S₁₀₅, A52G and C51S S76C. At last, we constructed an engineered bacteria Q16 using an optogenetic module BphS and the lysis cassette LUZ. The engineered strain was capable of adhering to target surface and achieving light-induced lysis by tuning the strength of ribosome binding sites (RBSs), showing great potential in surface modification.
Rhamnose/pharmacology* ; Plasmids/genetics* ; Pseudomonas aeruginosa ; Escherichia coli/metabolism*

α-L-rhamnosidase is a very important industrial enzyme that is widely distributed in a variety of organisms. α-L-rhamnosidase of different origins show functional diversity. For example, the optimal pH of α-L-rhamnosidase from bacteria is close to neutral or alkaline, while the optimal pH of α-L-rhamnosidase from fungi is in the acidic range. Furthermore, the enzymatic properties of α-L-rhamnosidases of different origins differ in terms of the optimal temperature, the thermal stability, and the substrate specificity, which determine the different applications of these enzymes. In this connection, it is crucial to elucidate the similarities and differences in the catalytic mechanism and substrate specificity of α-L-rhamnosidase of different origins through analyzing its enzymatic properties. Moreover, it is important to explore and understand the effects of aglycon and metal cations on enzyme activity and the competitive inhibition of L-rhamnose and glucose on enzymes. These knowledge can help discover α-L-rhamnosidase of industrial significance and promote its industrial application.
Glycoside Hydrolases/metabolism* ; Hydrogen-Ion Concentration ; Rhamnose ; Substrate Specificity ; Temperature

Rhamnolipid biosurfactant is mainly produced by Pseudomonas aeruginosa that is the opportunistic pathogenic strain and not suitable for future industrial development. In order to develop a relatively safe microbial strain for the production of rhamnolipid biosurfactant, we constructed engineered Escherichia coli strains for rhamnolipid production by expressing different copy numbers of rhamnosyltransferase (rhlAB) gene with the constitutive synthetic promoters of different strengths in E. coli ATCC 8739. We further studied the combinatorial regulation of rhlAB gene and rhaBDAC gene cluster for dTDP-1-rhamnose biosynthesis with different synthetic promoters, and obtained the best engineered strain-E. coli TIB-RAB226. Through the optimization of culture temperature, the titer of rhamnolipd reached 124.3 mg/L, 1.17 fold higher than that under the original condition. Fed-batch fermentation further improved the production of rhamnolipid and the titer reached the highest 209.2 mg/L within 12 h. High performance liquid chromatography-mass spectrometry (LC-MS) analysis showed that there are total 5 mono-rhamnolipid congeners with different nuclear mass ratio and relative abundance. This study laid foundation for heterologous biosynthesis of rhanomilipd.
Bacterial Proteins ; genetics ; Batch Cell Culture Techniques ; Decanoates ; Escherichia coli ; metabolism ; Fermentation ; Glycolipids ; biosynthesis ; Hexosyltransferases ; genetics ; Industrial Microbiology ; methods ; Multigene Family ; Promoter Regions, Genetic ; Pseudomonas aeruginosa ; Rhamnose ; analogs & derivatives ; biosynthesis ; Surface-Active Agents ; metabolism

The purpose of this study is to investigate the applicability of a natural swelling matrix derived from boat-fruited sterculia seed (SMS) as the propellant of osmotic pump tablets. The sugar components, static swelling, water uptake and viscosity of SMS were determined and compared with that of polythylene oxide (WSR-N10 and WSR-303). Both ribavirin and glipizide were used as water-soluble and water-insoluble model drugs. Then, the monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide were prepared using SMS as the osmotically active substance and propellant. SMS was mainly composed of rhamnose, arabinose, xylose and galactose and exhibited relatively high swelling ability. The area of the disintegrated matrix tablet was 20.1 times as that at initial after swelling for 600 s. SMS swelled rapidly and was fully swelled (0.5%) in aqueous solution with relative low viscosity (3.66 +/- 0.03) mPa x s at 25 degrees C. The monolayer osmotic pump tablets of ribavirin and the bilayer osmotic pump tablets of glipizide using SMS as propellant exhibited typical drug release features of osmotic pumps. In conclusion, the swelling matrix derived from boat-fruited sterculia seed, with low viscosity and high swelling, is a potential propellant in the application of osmotic pump tablets.
Arabinose ; chemistry ; isolation & purification ; Chemistry, Pharmaceutical ; Delayed-Action Preparations ; Drug Carriers ; Galactose ; chemistry ; isolation & purification ; Glipizide ; administration & dosage ; chemistry ; Osmosis ; Plants, Medicinal ; chemistry ; Rhamnose ; chemistry ; isolation & purification ; Ribavirin ; administration & dosage ; chemistry ; Seeds ; chemistry ; Solubility ; Sterculiaceae ; chemistry ; Tablets ; Technology, Pharmaceutical ; methods ; Viscosity ; Water ; Xylose ; chemistry ; isolation & purification

A new HPLC-UV technique for the separation and analysis of 10 monosaccharides achieved within 13.5 min using 1-phenyl-3-methyl-5-pyrazolone (PMP) as the labelling molecule of the reductive monosaccharides has been established by combining common high performance liquid chromatography-UV and C18 column. The established technique was applied to the quantification of the monosaccharide components in extract of Silybum marianum. The results showed that the tested 10 monosaccharides as PMP derivatives were baseline separated under the HPLC conditions proposed. It was confirmed that Silybum marianum extract was composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, xylose, galactose and arabinose with the molar ratio of 0.66:0.84:0.58:1.0:1.6:0.69:2.7:4.8. Quantitative recoveries of the compositional monosaccharides separated from the extract were in the range of 92.4%-104.0%, and the RSD values fell within 0.68%-3.81%. The results demonstrated that the proposed HPLC method was simple, rapid, convenient, and precise, and it was applicable to the analysis of the compositional monosaccharides of Silybum marianum extract.
Antipyrine ; analogs & derivatives ; chemistry ; Arabinose ; analysis ; Chromatography, High Pressure Liquid ; methods ; Galactose ; analysis ; Glucose ; analysis ; Glucuronic Acid ; analysis ; Hexuronic Acids ; analysis ; Mannose ; analysis ; Milk Thistle ; chemistry ; Monosaccharides ; analysis ; Plants, Medicinal ; chemistry ; Polysaccharides ; chemistry ; isolation & purification ; Quality Control ; Rhamnose ; analysis ; Seeds ; chemistry ; Spectrophotometry, Ultraviolet ; methods ; Xylose ; analysis

BACKGROUND: The MK1 strain, a novel bacterial isolate from soft-rotten tissue of the Neungee mushroom, produces copious amounts of exopolysaccharide (EPS) in a dextrose minimal medium. This study examined the molecular characteristics and immunomodulatory activity of MK1 EPS. METHODS: The EPS in the culture supernatant was purified by cold ethanol precipitation, and characterized by SDS-PAGE/silver staining and Bio-HPLC. The immunomodulatory activities of the EPS were examined using the mouse monocytic cell line, RAW 264.7 cells. RESULTS: The molecular weights of the purified EPS were rather heterogeneous, ranging from 10.6 to 55 kDa. The EPS was composed of glucose, rhamnose, mannose, galactose, and glucosamine at an approximate molar ratio of 1.00:0.8:0.71:0.29:0.21. EPS activated the RAW cells to produce cytokines, such as TNF-alpha and IL-1beta, and nitric oxide (NO). EPS also induced the expression of co-stimulatory molecules, such as B7-1, B7-2 and ICAM-1, and increased the phagocytic activity. The macrophage-activating activity of EPS was not due to endotoxin contamination because the treatment of EPS with polymyin B did not reduce the macrophage-activating activity. CONCLUSION: The EPS produced from the MK1 strain exerts macrophage-activating activity.
Agaricales ; Animals ; Cell Line ; Cold Temperature ; Cytokines ; Ethanol ; Galactose ; Glucosamine ; Glucose ; Intercellular Adhesion Molecule-1 ; Macrophages ; Mannose ; Mice ; Molar ; Molecular Weight ; Nitric Oxide ; Rhamnose ; Sprains and Strains ; Tumor Necrosis Factor-alpha

OBJECTIVETo isolate and purify the polysaccharides from Radix Rehmanniae and analysis the monosaccharides composition.

METHODThe polysaccharides were extracted with hot water and precipitated by alcohol. Proteins in the precipitates were removed by TCA method. The products were further purified with column chromatography on Superdex 200 and Sephadex G100. The SRP I and SRP II were identified as homogeneous polysaccharide by HPLC, respectively, and then analyzed by GC after being hydrolysised.

RESULTTwo homogeneous polysaccharides (SRP I and SRP II) were obtained from Radix Rehmanniae.

CONCLUSIONSRP I contained rhamnose, arabinose, glucose and galactose in the percentage of 6.11%, 66.46%, 3.93% and 21.50%. SRP I was composed of rhamnose, fucose, mannose, galactose and fructose in the percentage of 21.82%, 24.47%, 10.48%, 29.94% and 13.29%.

Arabinose ; chemistry ; isolation & purification ; Chromatography, Gas ; methods ; Clinical Laboratory Techniques ; Drugs, Chinese Herbal ; analysis ; Fructose ; chemistry ; isolation & purification ; Fucose ; chemistry ; isolation & purification ; Galactose ; chemistry ; isolation & purification ; Glucose ; chemistry ; isolation & purification ; Mannose ; chemistry ; isolation & purification ; Monosaccharides ; chemistry ; isolation & purification ; Plant Extracts ; chemistry ; Polysaccharides ; chemistry ; isolation & purification ; Rhamnose ; chemistry ; isolation & purification ; Scrophulariaceae ; chemistry

OBJECTIVETo study the chemical constituents from the active fractions against HIV in vitro, a crude ethanolic extract of Illicium simonsii.

METHODThe compounds were isolated with column chromatography methods. MS and NMR spectroscopic methods were used to determine the structures of the compounds.

RESULTSeven compounds were isolated from the active fractions against HIV in vitro of the 90% ethanol extract and their structures were elucidated as (+)-catechin (1), (-)-epicatechin (2), (+)-catechin 3-O-alpha-L-rhamnopyranoside (3), kaempferol 3-O-alpha-L-rhamnopyranoside (4), quercetin 3-O-alpha-L-rhamnopyranoside (5), erigeside C (6) and daucosterol (7).

CONCLUSIONSeven compounds were isolated from this plant for the first time, but none of them exhibited active against HIV in vitro. Compounds 3 and 6 were isolated from this genus for the first time.

Catechin ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Ethanol ; chemistry ; Glycosides ; chemistry ; Illicium ; chemistry ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Rhamnose ; analogs & derivatives ; chemistry ; Sitosterols ; chemistry

GL-PP-3A, an active polysaccharide peptide, was isolated and purified from Ganoderma lucidum, and then its structure was analyzed. Crude polysaccharide peptides were extracted from Ganoderma lucidum with hot water, precipitated with ethanol and then dialyzed from Ganoderma lucidum. Subsequently GL-PP-3A was isolated and purified from the crude polysaccharide peptides by fractional precipitation and chromatography of Bio-Gel P-10 column. The repetitive unit of GL-PP-3A was analyzed by high performance gel permeation chromatography (HPGPC), monosaccharide composition and methylation analysis, 1H NMR and 13C NMR. GL-PP-3A is a heteropolysaccharide which is composed mainly of glucose (Glc), and also contains saccharide residues such as rhamnose (Rha), xylose (Xyl), mannose (Man) and galactose (Gal) and 17 kinds of amino acids. Its weight-average molecular weight (Mw) and number-average molecular weight (Mn) were 1.7 x 10(4) and 1.1 x 10(4), respectively, with the ratio of Mw/Mn ( molecular weight distribution) being of 1.49. Its backbone chain is composed of 1,6-linked beta-D-Glcp and 1,3-liked beta-D-Glcp at a ratio of 2:1. Some of 1,6-linked glucose residuals of the backbone chain are substituted at 2-0 or 3-0, and there are 1 to 3 1,6-linked beta-D-Galp or 1,3-linked alpha-D-Manp in the branched chains, the nonreducing ends of which consist mainly of beta-D-Glcp and a few Rha.
Amino Acids ; analysis ; Chromatography, High Pressure Liquid ; Glucose ; analysis ; Magnetic Resonance Spectroscopy ; Molecular Weight ; Plants, Medicinal ; chemistry ; Polysaccharides ; chemistry ; isolation & purification ; Proteoglycans ; chemistry ; isolation & purification ; Reishi ; chemistry ; Rhamnose ; analysis ; Spectrophotometry, Ultraviolet

AIMTo study the bioactive constituents of the flower of Castanea mollissima Blume.

METHODSCompounds were isolated and purified by column chromatography of silica gel and TLC. Structures were determined by various spectroscopic data, including IR, 1HNMR and 13CNMR, EIMS, FABMS and HMBC as well as comparison of the data with those reported in literatures.

RESULTSFive compounds were isolated and elucidated as myricetin (I), quercetin (II), gallic acid (III), 4-quinolinone-2-caboxylic acid (IV), (+) -isolariciresinol-9'-O-alpha-L-rhamnoside (V).

CONCLUSIONThese compounds were separated from the flower for the first time and compound V is a new compounds, named chestnutlignansoide.

Fagaceae ; chemistry ; Flavonoids ; chemistry ; isolation & purification ; Flowers ; chemistry ; Molecular Structure ; Naphthols ; chemistry ; isolation & purification ; Plants, Medicinal ; chemistry ; Quercetin ; chemistry ; isolation & purification ; Rhamnose ; analogs & derivatives ; chemistry ; isolation & purification