Comparisons of Functional Properties of Polysaccharides from Nostoc flagelliforme under Three Culture Conditions.

Nostoc flagelliforme is an edible cyanobacterium with excellent food and herbal values. It has been used as food in China for more than 2000 years. Many studies have been focused on improving the yield and bioactivity of Nostoc flagelliforme polysaccharides although these have ignored the functional properties. In this study, we extracted and purified three polysaccharides (WL-CPS, NaCl-CPS and Glu-CPS) from Nostoc flagelliforme under normal, salt stress and mixotrophic culture conditions, respectively, in order to change the physicochemical properties of polysaccharides with the aim of obtaining better functional properties. Both salt stress and mixotrophic culture conditions increased the specific yield of polysaccharides. Their functional properties were comparatively investigated and the results showed that NaCl-CPS exhibited the highest emulsification activity and flocculation capability, which was also higher than that of some commercial products. In contrast, Glu-CPS exhibited the highest water and oil holding capacities, foaming property, intrinsic viscosity and bile acids binding capacity. Our results indicated that both NaCl-CPS and Glu-CPS could be considered to be functional polysaccharides according to their respective characteristics, which have great potential in numerous applications, such as food, pharmaceutical, cosmetic, chemical and mineral industries. These findings also demonstrated the potential application of the proper regulation of culture conditions in the development of polysaccharides with desired functional properties.

Quantitative analysis of cellular proteome alterations of Pseudomonas putida to naphthalene-induced stress.

OBJECTIVE: To investigate whether genes other than the operons nahAaAbAcAdBFCED and nahGTHINLOMKJ of Pseudomonas putida are involved in the tolerance of the bacterium to naphthalene. RESULTS: Cellular responses of P. putida ND6 grown with 2 and 4 g naphthalene/l were investigated using a quantitative proteomic-based approach. Comparative analysis of the proteome data identified that the expression levels of 22 proteins involved in heat shock and universal stress response, naphthalene degradation, cell envelope synthesis, and motility were up-regulated; while the expression levels of 26 proteins involved in protein and fatty acid synthesis, carbon compound, nucleotide, and amino acid metabolism, and small molecule transport were down-regulated. CONCLUSION: Our findings offer insights into the cellular response of P. putida to high naphthalene concentrations at the protein level.

Development of Loop-Mediated Isothermal Amplification (LAMP) for Universal Detection of Enteroviruses.

Enteroviruses are found in most environments and cause several diseases in humans. Loop-mediated isothermal amplification (LAMP) was adapted and evaluated for the rapid detection of enteroviruses. Based on the highly conserved 5' untranslated region (5'-UTR) of the human enteroviruses (HEVs), particularly human enterovirus A (HEV-A) and HEV-B, a set of universal primers was designed. The LAMP amplification was carried out under isothermal conditions at 61 °C, depending on the template concentration results were obtained within 45-90 min. The detection limits were found to be 10(1) copies of cloned enterovirus 71 fragments, more sensitive than conventional PCR. Nine water samples collected from drinking water sources during three seasons and 19 stool specimens collected from HFMD patients were analyzed. By using the LAMP assay, the majority of samples was tested positive, 9/9 (100 %) and 18/19 (94.7 %), respectively. LAMP is a practical method for the rapid detection of enteroviruses in environmental and clinical samples.

Cross-talk of the related bioactivity mediators in serum after injection of soluble TNF-α receptor on silicosis model of rats.

This study investigates cross-talk of the related bioactivity mediators in silica-induced pulmonary inflammatory and fibrosis on rats, which contributes to the preventive and therapeutic effect of soluble TNF-α receptor. Wistar rats received saline or 50 mg of quartz by intratracheal instillation. Rats in drug-treated groups were given soluble tumor necrosis factor-α (TNF-α) receptor (500 µg) by hypodermic injection on days 1, 5 and 8 after operation. At 7 days or 14 days after instillation, rats were killed to observe the degree of injury and expression of the related bioactivity mediators including nuclear factor KB (NF-KB), nitric oxide, interleukin-1ß, interleukin-10, transforming growth factor beta 1 (TGF-ß1), TNF-α, interferon-Y (IFN-Y) and granulocyte macrophage colony-stimulating factor (GM-CSF). The area percentages of type I and III collagens in intervention group were lower than those in silica group. The expression of NF-κB, TGF-ß1, and COL I were lower in intervention group than in silica group(p < 0.05) and GM-CSF was significantly higher (p < 0.05) at 7 days after instillation, however, NF-κB, TGF-ß1, and COL I were identically lower in intervention group than in silica group, and TNF-α, IFN-γ, and GM-CSF were higher at 14 days after instillation. It may be concluded that soluble TNF-α receptor upregulating or downregulating the expression of the related bioactivity mediators results in decreasing lung injury induced by silica.

[Screening and identification of differential expression genes related to stress fracture by cDNA microarray assay].

OBJECTIVE: To evaluate the differentially expressed genes between the Stress fracture (SF) cases and controls. METHODS: Total RNA was extracted and purified from peripheral blood sample of 3 SF cases and 3 controls who conducted a 1:1 matched case-control study, then used for Human Genome Array analysis. The hybridization data were analyzed using SAM software. Parts of these genes were analyzed and identified by real-time PCR. RESULTS: Upregulated and downregulated genes were 22 and 1, respectively. Thus the highest ratio and most significant cytokine was tumor necrosis factor receptor superfamily, member 10c (TNFRSF10C). The result of real-time PCR shows that TNFRSF10C was over-expressed in 3 cases and low-expressed in 1 case. CONCLUSION: Obvious difference exists in gene expression between SF cases and controls, showing there may be a lot of genes involving in the occurrence and development of SF. Meanwhile, the identification of the specific genes is helpful for biomechanics study, early diagnosis and screening of SF.

[Detection and quantification of hepatitis A virus in Tianjin coastal seawater of Bohai Bay].

Hepatitis A virus (HAV) is single-strainded RNA virus that causes infectious hepatitis A. Detection and quantification of hepatitis A virus in Tianjin coastal seawater of Bohai Bay were carried out by conventional RT-PCR and SYBR Green real-time quantitative RT-PCR using the primers based on the conserved sequence at the VP1-VP2 genes of HAV. The nine samples were taken at Tianjin coastal seawater of Bohai Bay locating in the south of Tanggu, in summer, autumn and winter of 2007 and spring of 2008. For viral detection, seawater samples were concentrated either using a small ultrafiltration system (Millipore Pellicon Mini TFF) or a Centriprep-100 centrifugal ultrafiltration device (Millipore Centricon Plus-70). RT-PCR analysis showed that a 192 bp HAV cDNA was amplified from all nine seawater samples and the sequence identities of these cDNAs to the homologous sequence in the GenBank were between 95% and 100%. SYBR Green real-time quantitative RT-PCR analysis indicated that HAV concentration in these samples ranged from 5.35 x 10(6) to 4.51 x 10(7) virus particles/L.

[Isolation and identification of phenol-degrading strains and the application in biotreatment of phenol-containing wastewater].

Ten phenol-degrading bacterial strains were isolated from mixture of activated sludge and wastewater of a petroleum chemical plant. The five isolates (PD1, PD2, PD6, PD7 and PD39) were identified as Pseudomonas sp.,the four (PD4, PD5, PD8 and PD9) as Acinetobacter sp.,and the one (PD3) as Comamonas sp.by 16S rDNA sequence. Biodegradation characteristics of phenol, optimal conditions for growth, substrate range, activities of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase, and biotreatment of phenol-containing wastewater of Pseudomonas sp.PD39 were investigated in detail. The results indicated that the optimal conditions for growth and degradation of strain PD39 are beginning pH of medium 7.0, growth temperature 30 degrees C, concentration of phenol 800 mg/L. PD39 was capable of metabolizing phenol at concentrations up to 1200 mg/L and removing 637 mg/L in industrial wastewater by 99.96% in 72 h. This strain possesses a good application potential as a bioaugmentation strain in the activated sludge system for treatment of phenol-containing wastewater.

Biodegradation of phenol by free and immobilized Acinetobacter sp. strain PD12.

A new phenol-degrading bacterium with high biodegradation activity and high tolerance of phenol, strain PD12, was isolated from the activated sludge of Tianjin Jizhuangzi Wastewater Treatment Facility in China. This strain was capable of removing 500 mg phenol/L in liquid minimal medium by 99.6% within 9 h and metabolizing phenol at concentrations up to 1100 mg/L. DNA sequencing and homologous analysis of 16S rRNA gene identified PD12 to be an Acinetobacter sp. Polyvinyl alcohol (PVA) was used as a gel matrix to immobilize Acinetobacter sp. strain PD12 by repeated freezing and thawing. The factors affecting phenol degradation of immobilized cells were investigated, and the results showed that the immobilized cells could tolerate a high phenol level and protected the bacteria against changes in temperature and pH. Storage stability and reusability tests revealed that the phenol degradation functions of immobilized cells were stable after reuse for 50 times or storing at 4 degrees C for 50 d. These results indicate that immobilized Acinetobacter sp. strain PD12 possesses a good application potential in the treatment of phenol-containing wastewater.

[Cloning and expression of catA gene from Pseudomonas putida ND6 and study on the catechol cleavage pathway].

Catechol 1,2-dioxygenase gene, calA, from naphthalene-degrading plasmid pND6-1 of Pseudomonas putida ND6, was cloned and expressed in Escherichia coli. Enzymic properties of the expressed product were investigated. The results indicated that the Km and Vmax of the enzyme are 0.019 mol/L and 1.434 mol/(min x mg), respectively. The enzyme possessed a thermal stability and 93.7% activity was retained after incubating at 50 degrees C for 45 min. Fe2+ could enhance the enzyme activity by 292%. The enzyme displayed a lower activity against 4-chlorocatechol and belongs to group I of catechol 1,2-dioxygenases. When naphthalene was used as a substrate for growth of strain ND6, catechol 1, 2-dioxygenase and catechol 2,3-dioxygenase activities were both detected in their crude extract. However, when strain ND6 was grown on benzoate, rho-hydroxybenzoic acid or phenylacetic acid as a sole source of carbon the activity of catechol 1,2-dioxygenase was much higher than that of catechol 2,3-dioxygenase. These indicated that strain ND6 is able to metabolize naphthalene by catechol meta- and ortho-cleavage pathways. When benzoate, rho-hydroxybenzoic acid and phenylacetic acid were used as growth substrates, strain ND6 degrades these compounds only by catechol ortho-cleavage pathway.

[Optical detection system for micro biochemical analyses].

For the need of biochemical chip, which consumes fewer specimens and is easy to integrate with micro-fluid chip, two kinds of spectrophotometric analysis methods are described in the present paper. Both the direct detection method and evanescent wave detection method are used in the experiments with visible light (460-800 nm). The experimental results proved that the direct detection is simple and evident; on the other hand the evanescent wave detection method consumes much less reagent and is easy to integrate with microchips.