Synthesis, herbicidal activities, and 3D-QSAR of 2-cyanoacrylates containing aromatic methylamine moieties.

A series of novel 2-cyanoacrylates containing different aromatic rings were synthesized, and their structures were characterized by (1)H NMR, elemental analysis, and single-crystal X-ray diffraction analysis. Their herbicidal activities against four weeds and inhibition of photosynthetic electron transport against isolated chloroplasts (the Hill reaction) were evaluated. Both in vivo and in vitro data showed that the compounds containing benzene, pyridine, and thiazole moieties gave higher activities than those containing pyrimidine, pyridazine, furan, and tetrahedronfuran moieties. To further explore the comprehensive structure-activity relationship on the basis of in vitro data, comparative molecular field analysis (CoMFA) was performed, and the results showed that a bulky and electronegative group around the para-position of the aromatic rings would have the potential for higher activity, which offered important structural insights into designing highly active compounds prior to the next synthesis.

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.

[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.