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Abstract: Low molecular weight alginate-derived oligosaccharide (ADO) (373–571Da) and chito-oligosaccharide (COS) (855–1671Da) were purified from alginate and chitosan, and known as marine oligosaccharides with polyanionic and polycationic properties, respectively. We compared the effects of ADO and COS on cell regulation using several biological models (Candida albicans, Escherichia coli and Bacillus subtilis spore), cellular uptake determination, erythrocytes haemolysis inhibition and antioxidant capacity assay to investigate stress response under UV radiation. Our results further confirmed the anti-UVR potential of ADO and COS and their potential for commercial UVR protector application in the area of functional foods as food ingredients. [Copyright &y& Elsevier]

Abstract: Alginate lyase which was purified from the fermentation solution of marine bacteria Pseudomonas sp. HJZ216 was applied to hydrolyze algae alginate. Six oligosaccharides, including di- and trisaccharides, were isolated and purified through anion exchange chromatography. The oligosaccharide structures were elucidated based on electrospray ionization-mass spectrometry (ESI-MS) and 2D NMR spectra analysis. [Copyright &y& Elsevier]

Abstract: Gold(I) and (III) salts have been found to be highly effective at the catalysis of ether formation from alcohols. Intramolecular ether formation of a 1,5-diol was also achieved, with a stereoselectivity that indicates that an SN1 mechanism predominates. In an attempt to form a seven-membered ring, a stable 14-membered dimer product was also formed. Attempts to control the diastereoselectivity of the reaction using a chiral anionic counterion did not give products with a high de. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis and biological evaluation of a series of diphenyl ether derivatives were described. The compounds can either activate or inhibit the aminopeptidase activity of leukotriene A4 hydrolase, while at the same time do not influence the hydrolase activity. Further enzyme kinetics and molecular modeling investigation on these novel chemical activators revealed their possible activation mechanism. These compounds can be used as probes to regulate the aminopeptidase activity of leukotriene A4 hydrolase. [Copyright &y& Elsevier]

Summary: The water-soluble exopolysaccharide (WSEPS) from Pantoea agglomerans strain KFS-9 isolated from mangrove forest was prepared by removing bacterial cell from the fermentation liquid following by concentration and cold ethanol precipitation of the supernatant. The polysaccharide material was purified by gel permeation chromatography on a Sephacryl S-300HR column and characterized using chemical and spectral methods. The results show that WSEPS is protein-bound polysaccharide, and it is composed of arabinose, glucose galactose and gulcuronic acid in the molar ratio of 1.0:2.2:2.8:0.9. Their antioxidant activities in vitro were studied by various antioxidant assays, including hydroxyl radical scavenging, superoxide radical scavenging and antilipid peroxidation. The results show that the WSEPS extracted had a high antioxidant activity in a concentration-dependent manner (except the activity of antilipid peroxidation). WSEPS quenched hydroxyl radicals, superoxide radicals at low amounts, the IC50 of which were 0.07 and 0.15mg/ml, respectively. These results indicate that the protective effect of WSEPS against UV radiation is most likely to be due to the free radicals-scavenging ability. [Copyright &y& Elsevier]

Abstract: A novel surfactant- and oxidation-stable alkaline protease from Vibrio metschnikovii DL 33–51 was purified using acetone precipitation, Q-sepharose ion exchange and Sephacryl S-100 gel filtration chromatographic techniques. The enzyme had a relative molecular weight of 29.5kDa by SDS polyacrylamide gel electrophoresis. The optimal temperature and pH were found to be 60°C and 12.0, respectively. The protease was stable in a pH range of 9.0–11.0. The half-lives of protease recorded at 50 and 60°C were 7.5h and 30min, respectively. The enzyme activity could be strongly activated by several commercially available laboratory surfactants (Triton X-100, Tween-80) and bleaches (H2O2, sodium hypochlorite), and showed a valuable stability towards them when their concentrations ranged up to 1.0%. Enzyme activity was increased up to 19 and 18% by Mn2+ and Ba2+, respectively. [Copyright &y& Elsevier]

• Near standard soil samples are produced under the laboratory condition. • Spectral response characteristics of soil Cd are identified. • All the hyperspectral wavelengths are indicative of soil Cd concentrations. • Multisource spectra are enhanced by combining DS and Spiking algorithm. • Accuracy of soil Cd estimation is improved by the integrated multisource spectra. Benefiting from the advantages of a wide spatial sampling range and strong continuity, hyperspectral analysis provides a potential way to detect heavy metals in soil. However, it is still a great challenge to identify the spectral response characteristics of heavy metals from naturally polluted soil samples. This paper innovatively produces near standard soil samples for exploring the exact spectral response of cadmium (Cd) in soil and presents a novel method by combining the direct standardization (DS) and Spiking algorithms for integrating multisource spectra to improve the accuracy of Cd concentration estimation. A total of 46 naturally polluted soil samples were collected from a known Cd-contaminated mining area in Xiangjiang River Basin, China. The soil spectra of the naturally polluted soil samples were synchronously measured in the field. Moreover, clean soils with low heavy metal contaminants were collected to produce 65 near standard soil samples with known Cd levels. Then, the spectra and Cd concentrations of all 111 soil samples were measured under laboratory conditions. The principle component stepwise regression (PCSR) analysis results illustrated that the reflectance at all the wavelengths (380–2460 nm) is indicative of the differences in the soil Cd concentrations. Among these, the sensitivity of the spectral reflectance is the strongest at approximately 400 nm, 1000 nm and above 2300 nm. Additionally, the integrated multisource spectra significantly improved the accuracy of soil Cd concentration estimation (coefficient of determination, R2 = 0.96; root mean square error, RMSE = 0.29; ratio of prediction to deviation, RPD = 1.21) when 30 transfer samples and 15 training samples were simultaneously implemented in the combined DS and Spiking algorithm. This will provide a feasible scheme for exploration of spectral response characteristics of multiple soil heavy metals, and highlight the potential of developing low-level and satellite remote sensing on a large scale. [ABSTRACT FROM AUTHOR]

Extracellular polysaccharide (EPS) produced by Pantoea agglomerans was purified for structural analysis and anti-UVB activity evaluation. The results showed that the EPS comprised of mannose and glucose in a ratio of 3:2. The molecular weight of EPS was estimated as 679 KDa. Fourier transform infrared spectrometry (FT-IR) showed that the EPS was composed of d -furanose without any substituent group. The structure of the EPS could be deduced as a repeated pentasaccharide arranged of three mannose molecules and two glucose molecules according to electrospray ionization mass spectrometry (ESI-MS) analysis and results mentioned above. The results also showed that the EPS attenuated UVB-induced cytotoxicity which was verified by morphology feature assay, down-regulated the expression of phosphor-JNK and active caspase3 significantly through MAPK pathway in UVB-irradiated HaCaT cells, and therefore protected the cells from apoptosis which could be identified by the lower apoptosis rate at low dose of UVB ray. In conclusion, the EPS as a macromolecule arranged by repeated pentasaccharide could protect HaCaT keratinocytes from UVB irradiation injury effectively, and the underlying mechanism may involve MAPK signaling pathway which contribute to apoptotic cell death. However, further studies on efficacy of the EPS in vivo are needed to determine. • EPS was confirmed as a repeated hetero-pentasaccharide. • The EPS decreased UVB-induced cytotoxicity and apoptosis rate. • This is the first report of the EPS on mechanism of anti-UVB irradiation. [ABSTRACT FROM AUTHOR]

Abstract A β-agarase was identified from Pseudoalteromonas sp. Q30F and heterologously expressed in Bacillus subtilis WB800n. The β-agarase, Aga862 encoded by aga862 gene in an open reading frame of 1338 bp is 445 amino acids in length, and has a calculated molecular mass of 50.1 kDa and an estimated isoelectric point of 4.81. Protein sequence analysis showed that Aga862 belongs to family 16 of glycoside hydrolases (GH16) and carbohydrate-binding module family 13 (CBM13). The agarase was expressed in B. subtilis WB800n and purified by precipitation, anion exchange and gel filtration for a specific activity of 4.6 U/mg, a 27.8-fold improvement over the activity of the crude enzyme. Aga862 exhibited optimal activity at 45 °C and pH 6.5, and showed excellent pH stability with retention of over 80% relative activities after preincubation for the pH range of 3.0–10.0 at 4 °C for 3 h. The agarase exhibited a K m value of 14.15 mg/mL toward agarose and a V max of 256.41 U/mg. The mass spectrometry analysis revealed that the end products of agar degradation were neoagarotetraose and neoagarohexaose. Recombinant Aga862 has great potential for the manufacture of agaro-oligosaccharides for the non-pathogenic nature and safety of the B. subtilis WB800n. Highlights • A β-agarase Aga862 from Pseudoalteromonas sp. Q30F was expressed in B. subtilis. • After purification, the specific activity of Aga862 increased by 27.8 times. • Aga862 optimum activity was at 45 °C, pH 6.5, with excellent pH stability. • Aga862 is expected to be an industrial zymin to produce NA4 and NA6. [ABSTRACT FROM AUTHOR]

Yield, physico-chemical and gelling properties of agar from Gracilaria tenuistipitata as affected by alkaline treatments conditions at various levels were investigated. Agar with alkaline treatment, especially at higher alkali concentration, showed better gelling property as evidenced by higher gel strength (624.4–1250.8 g cm −2 ), gelling (28.1–43.2 °C) and melting (96.4–99.6 °C) temperatures with coincidentally increased 3,6-anhydrogalactose content (38.93%–44.78%) and decreased sulphate content (7.79%–3.48%), but reducing yield (22.34%–15.61%). Treatment temperature or time has a positive influence on agar properties in appropriate range, while higher temperature or longer time might result in yield reducing. Alkaline treatment with 6% alkali at 80 °C for 1.5 h was the optimal pretreatment process, with the gel strength reached to 1068.15 g cm −2 and obtained high yield (23.14%), which are higher than the earlier reports. Meanwhile, the study of the correlation between physico-chemical and gelling properties of agar confirmed that the gel strength has negative correlation relationship with sulphate content (p < 0.05), while positive correlation with 3,6-anhydrogalactose content (p < 0.01) and gelling (p > 0.05) or melting temperatures (p > 0.05). Overall, this work suggested the feasibility of the exploitation of G . tenuistipitata for production of superior quality agar, which are mainly from Gelidium species. [ABSTRACT FROM AUTHOR]

An extracellular chondroitinase ABC (ChSase ABC, EC 4.2.2.4) produced by cultivating Acinetobacter sp. C26, was purified to homogeneity from the supernatant by ammonium sulfate fractionation, Q-Sepharose Fast Flow and Sephadex G-100 chromatography. The 76 kDa enzyme was purified 48.09-fold to homogeneity with specific activity of 348.64 U/mg, Using the chondroitin sulfate A (CS-A) as substrate, the maximal reaction rate (Vmax) and Michaelis-Menten constant (Km) of ChSase ABC were found to be 10.471 μmol/min/ml and 0.105 mg/ml, respectively. The enzyme showed the highest activity at the optimal conditions of pH 6.0 and 42 ∘C, respectively. This enzyme was stable at pH 5–10, 5–9 and 5–7 at 4 °C, 37 °C and 42 °C, respectively. Investigation about thermal stability of ChSase ABC displayed that it was stable at 37 °C. ChSase ABC activity was increased in presence of Na + , K + , Mn 2+ , 1,10-phenanthrolin and strongly inhibited by Cu 2+ , Hg 2+ , Al 3+ and SDS. These properties suggested that ChSase ABC from Acinetobacter sp. C26 bring promising prospects in medical and industry applications. [ABSTRACT FROM AUTHOR]

Extracellular polysaccharide (EPS) produced by Bacillus megaterium GJT321 was isolated from fermentation broth and further purified by gel filtration chromatography. The molecular weight of EPS was estimated as 1946 kDa by gel permeation chromatography (GPC), so this EPS was determined as macromolecular polysaccharide. Fourier transform infrared spectrometry (FT-IR) showed that the kind of heterocyclic compound composing EPS was furanose. The structural characteristics of EPS were investigated by means of enzymatic method, electrospray ionization mass spectrometry (ESI–MS) and NMR spectra analysis. The structure elucidation of the EPS was accomplished, and it was β − (2, 6) −D− fructofuranose, namely levan. [ABSTRACT FROM AUTHOR]

Extracellular polysaccharide (EPS) and intracellular polysaccharide (IPS) were produced in a mycelial liquid culture of the Hirsutella sp . liquid fermentation. The polysaccharides were precipitated with 50% ethanol (EPS-1, IPS-1), 65% ethanol (EPS-2, IPS-2) and 80% ethanol (EPS-3, IPS-3). The polysaccharide fragments precipitated in lower ethanol percentages had a lower neutral sugar content and a larger molecular weight. EPS-1, EPS-2, IPS-1 and IPS-2 were composed of glucose (Glu), galactose (Gal) and mannose (Man). Galactose was not detected in EPS-3 and IPS-3. Evaluated by the 1/IC 50 values of hydroxyl radical scavenging activity, the polysaccharides with higher protein content, lower neutral sugar content and molecular weight about 10–20 kDa were found to have better radical scavenging activity. Significant correlations demonstrated that the antioxidant effect of the polysaccharides was influenced by monosaccharide composition (mannose, r = 0.942; glucose, r = −0.905). [ABSTRACT FROM AUTHOR]

In this paper we describe how utilization of low molecular weight alginate-derived oligosaccharide (ADO) and chito-oligosaccharide (COS) in conjunction with antibiotics, could more effectively inhibit the growth of wild-type and resistant Pseudomonas aeruginosa. Inhibition is effected by modulating the bacteria's quorum sensing (QS) system, thus regulating biofilm formation and reducing resistance to antibiotic treatment. This can be demonstrated by using conventional MIC screening. COS showed synergistic effects with azithromycin, whereas ADO indicated additive effects against wild-type P. aeruginosa. Using electrospray-ionization mass spectroscopy (ESI-MS), matrix-assisted laser desorption/ionization-time of flightmass spectroscopy (MALDI-TOF-MS) and nuclear magnetic resonance (NMR), the chemical structure of ADO and of COS was characterized. The wild-type and resistant strains were identified by 16S rRNA sequence analysis. This report demonstrates the feasibility of attenuating the tolerance of P. aeruginosa to azithromycin by using specific marine oligosaccharides. [ABSTRACT FROM AUTHOR]

Highlights: [•] A newly bacterium secreted enzymes to degrade PE was isolated and identified. [•] Enzymes show high efficiency and specificity to PE with 63.53% of reducing sugar. [•] This kind of enzyme provides a new method to research the structure of PE. [•] This study provides the necessary information to aware of this kind of enzymes. [ABSTRACT FROM AUTHOR]

Alginate that was purified from the fermentation solution of marine bacteria Vibro sp. 510 under specific reaction conditions was hydrolyzed by alginate lyase. Seven oligosaccharides, including di-, tri- and tetrasaccharides, were isolated through low-pressure, gel-permeation chromatography (LP-GPC) and semipreparative strong-anion exchange (SAX) fast-protein liquid chromatography (FPLC). The oligosaccharide structures were elucidated based on ESIMS and 2D NMR spectral analysis. The hydrolytic specificity of this alginate lyase to alginate is discussed. [Copyright &y& Elsevier]