Biodegradation of nicotine by newly isolated Pseudomonas sp. CS3 and its metabolites

AIMS

Isolation and characterization of nicotine-degrading bacteria with advantages suitable for the treatment of nicotine-contaminated water and soil and detection of their metabolites.

METHODS AND RESULTS

A novel nicotine-degrading bacterial strain was isolated from tobacco field soil. Based on morphological and physiochemical properties and sequence of 16S rDNA, the isolate was identified as Pseudomonas sp., designated as CS3. The optimal culture conditions of strain CS3 for nicotine degradation were 30°C and pH 7·0. However, the strain showed broad pH adaptability with high nicotine-degrading activity between pH 6·0 and 10·0. Strain CS3 could decompose nicotine nearly completely within 24 h in liquid culture (1000 mg L(-1) nicotine) or within 72 h in soil (1000-2500 mg kg(-1) nicotine) and could endure up to 4000 mg L(-1) nicotine in liquid media and 5000 mg kg(-1) nicotine in soil. Degradation tests in flask revealed that the strain had excellent stability and high degradation activity during the repetitive degradation processes. Additionally, three intermediates, 3-(3,4-dihydro-2H-pyrrol-5-yl) pyridine, 1-methyl-5-(3-pyridyl) pyrrolidine-2-ol and cotinine, were identified by GC/MS and NMR analyses.

CONCLUSIONS

The isolate CS3 showed outstanding nicotine-degrading characteristics such as high degradation efficiency, strong substrate endurance, broad pH adaptability, and stability and persistence in repetitive degradation processes and may serve as an excellent candidate for applications in the bioaugmentation process to treat nicotine-contaminated water and soil. Also, detection of nicotine metabolites suggests that strain CS3 might decompose nicotine via a unique nicotine-degradation pathway.

SIGNIFICANCE AND IMPACT OF THE STUDY

The advantage of applying the isolated strain lies in broad pH adaptability and stability and persistence in repetitive use, the properties previously less focused in other nicotine-degrading micro-organisms. The strain might decompose nicotine via a nicotine-degradation pathway different from those of other nicotine-utilizing Pseudomonas bacteria reported earlier, another highlight in this study.

Analysis of clinical data of patients with different outcomes after short-time insemination

The study is to analyse the clinical data of the two groups of patients with different fertilisation outcomes after short-time insemination and probe into short-time insemination indications. A retrospective study including 558 cycles of short-time insemination in our centre during January 2009 to June 2010 which were divided into two groups by the method of fertilisation, 472 cycles by IVF and 86 cycles by Re-ICSI group according to fertilisation conditions to and compare the differences between the two groups in the indexes of average female age, average male age, duration of infertility, forward-moving sperm counts, abnormal sperm rate, proportion of primary infertility, etc. The differences between the two groups have statistical significance in duration of infertility, forward-moving sperm counts, abnormal sperm rate and proportion of primary infertility (5.02 ± 3.12 versus 5.86 ± 3.35; 83.06 ± 78.55 versus 54.02 ± 61.78; 83.56 ± 5.24% versus 86.31 ± 5.26%; 56.87% versus 74.42%; P < 0.05). The discrepancy between the two groups has no statistical significance in average female age and average male age (P > 0.05). Duration of infertility, forward-moving sperm counts, abnormal sperm rate and previous pregnancy history have great significance to predict fertilisation failure, so decisions should be made on the basis of the above indexes when evaluating whether a patient should conduct short-time insemination.

Features of Hirayama Disease on Fully Flexed Position Cervical MRI

This study reports on cervical magnetic resonance imaging (MRI) performed in the fully flexed position in 13 male patients with Hirayama disease and 12 normal controls (males). The anterior–posterior diameter of the cervical cord at the superior margin of the C6 vertebral body was measured, as well as the angle between adjacent cervical bodies. Localized lower cervical-cord atrophy, cord flattening and abnormal signals in the posterior epidural space were studied. Patients demonstrated an increased angle between C5 and C6, and C6 cord lesions. There were significant differences between patients and controls in localized lower cervical-cord atrophy and cord flattening. Many patients were found to have a crescent-shaped high-intensity mass on T2WI MRI and a low-intensity mass on T1WI MRI in the posterior epidural space. In patients, there were specific imaging features of Hirayama disease on fully flexed MRI. Cervical MRI in the fully flexed position has significant value in the clinical diagnosis of Hirayama disease.

Eutrophication of lake waters in China: cost, causes, and control

Lake water eutrophication has become one of the most important factors impeding sustainable economic development in China. Knowledge of the current status of lake water eutrophication and determination of its mechanism are prerequisites to devising a sound solution to the problem. Based on reviewing the literature, this paper elaborates on the evolutional process and current state of shallow inland lake water eutrophication in China. The mechanism of lake water eutrophication is explored from nutrient sources. In light of the identified mechanism strategies are proposed to control and tackle lake water eutrophication. This review reveals that water eutrophication in most lakes was initiated in the 1980s when the national economy underwent rapid development. At present, the problem of water eutrophication is still serious, with frequent occurrence of damaging algal blooms, which have disrupted the normal supply of drinking water in shore cities. Each destructive bloom caused a direct economic loss valued at billions of yuan. Nonpoint pollution sources, namely, waste discharge from agricultural fields and nutrients released from floor deposits, are identified as the two major sources of nitrogen and phosphorus. Therefore, all control and rehabilitation measures of lake water eutrophication should target these nutrient sources. Biological measures are recommended to rehabilitate eutrophied lake waters and restore the lake ecosystem in order to bring the problem under control.

Boosted expression of the SARS-CoV nucleocapsid protein in tobacco and its immunogenicity in mice

Vaccines produced in plant systems are safe and economical; however, the extensive application of plant-based vaccines is mainly hindered by low expression levels of heterologous proteins in plant systems. Here, we demonstrated that the post-transcriptional gene silencing suppressor p19 protein from tomato bushy stunt virus substantially enhanced the transient expression of recombinant SARS-CoV nucleocapsid (rN) protein in Nicotiana benthamiana. The rN protein in the agrobacteria-infiltrated plant leaf accumulated up to a concentration of 79 microg per g fresh leaf weight at 3 days post infiltration. BALB/c mice were intraperitoneally vaccinated with pre-treated plant extract emulsified in Freund's adjuvant. The rN protein-specific IgG in the mouse sera attained a titer about 1:1,800 following three doses of immunization, which suggested effective B-cell maturation and differentiation in mice. Antibodies of the subclasses IgG1 and IgG2a were abundantly present in the mouse sera. During vaccination of rN protein, the expression of IFN-gamma and IL-10 was evidently up-regulated in splenocytes at different time points, while the expression of IL-2 and IL-4 was not. Up to now, this is the first study that plant-expressed recombinant SARS-CoV N protein can induce strong humoral and cellular responses in mice.

Preparation of activated carbons from wet activated sludge by direct chemical activation

An improved method for preparing activated carbons from wet waste activated sludge (WAS) by direct chemical activation was studied in this paper. The effects of processing parameters on iodine adsorption capacity of the product were investigated. Results show that sludge-based activated carbon prepared with KOH had a larger iodine value than those activated with ZnCl(2) and KCl. The maximum iodine value was observed at the KOH concentration of 0.50 M. Increasing the impregnation time from 10 to 20 h resulted in a 20% increase in the iodine value. The highest iodine value was obtained at the activation temperature of 600 degrees C and holding time of 1 h. Sludge water content had insignificant effects on the iodine value of products. Raw WAS with a water content of 93.2% can be converted into an activated carbon with a high specific surface area of 737.6 m(2) g(-1) and iodine value of 864.8 mgg(-1) under optimum experimental conditions. Other physical properties such as total pore volume, micropore volume and mean pore diameter of the product were also reported and compared with those of commercial activated carbon.

Determination of TAP1 and TAP2 polymorphism in the Chinese Han population by real-time TaqMan polymerase chain reaction

The heterodimeric transporter associated with antigen processing (TAP) complex plays a key role in immune surveillance. TAP1 and TAP2 typing was usually performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism and PCR-sequence-specific oligonucleotide probe. As an alternative to these methods, we have established TaqMan assays to determine the frequencies of the TAP1 and TAP2 alleles. We have used these new TaqMan assays to genotype the polymorphisms in 339 unrelated Chinese Hans residing in North and South China. We detected five TAP1 and four TAP2 alleles. All the loci conform to the Hardy-Weinberg expectations. The most frequent alleles in Chinese Hans were TAP1*0101 (79.79%) and TAP2*0101 (82.74%). The two-locus haplotype analysis showed highly significant positive linkage disequilibrium for one TAP1-TAP2 haplotype (TAP1*020101-TAP2*0102), three TAP1-DRB1 haplotypes (TAP1*020101-DRB1*03, TAP1*020102-DRB1*13, and TAP1*0301-DRB1*16), and three TAP2-DRB1 haplotypes (TAP2*0102-DRB1*09, TAP2*0103-DRB1*04, and TAP2*0201-DRB1*01). The three-locus haplotype analysis showed highly significant positive linkage disequilibrium for TAP1*0101-TAP2*0101-DRB1*07, TAP1*0101-TAP2*0103-DRB1*04, TAP1*020101-TAP2*0101-DRB1*03, and TAP1*020101-TAP2*0102-DRB1*13. Comparison of the allele frequencies with those of other populations showed that the TAP1 allele distribution was very similar in all the groups, except for the Guarani, Kaingang, and Anatolian populations, but TAP2 distribution was significantly different from that of the other populations. The new TaqMan method provides relatively accurate, high-resolution, simple, and fast assays for TAP genotyping.

Knockout of the AtCESA2 gene affects microtubule orientation and causes abnormal cell expansion in Arabidopsis

Complete cellulose synthesis is required to form functional cell walls and to facilitate proper cell expansion during plant growth. AtCESA2 is a member of the cellulose synthase A family in Arabidopsis (Arabidopsis thaliana) that participates in cell wall formation. By analysis of transgenic seedlings, we demonstrated that AtCESA2 was expressed in all organs, except root hairs. The atcesa2 mutant was devoid of AtCESA2 expression, leading to the stunted growth of hypocotyls in seedlings and greatly reduced seed production in mature plants. These observations were attributed to alterations in cell size as a result of reduced cellulose synthesis in the mutant. The orientation of microtubules was also altered in the atcesa2 mutant, which was clearly observed in hypocotyls and petioles. Complementary expression of AtCESA2 in atcesa2 could rescue the mutant phenotypes. Together, we conclude that disruption of cellulose synthesis results in altered orientation of microtubules and eventually leads to abnormal plant growth. We also demonstrated that the zinc finger-like domain of AtCESA2 could homodimerize, possibly contributing to rosette assemblies of cellulose synthase A within plasma membranes.

Overexpression of human reticulon 3 (hRTN3) in astrocytoma

Neuroendocrine-specific protein (NSP) reticulons (RTN) are endoplasmic reticulum-associated protein complexes, which are localized in the endoplasmic reticulum (ER) and identified as markers for neuroendocrine differentiation. At least 4 different RTN genes have been identified in mammals, but in most cases, the functions of the encoded proteins except mammalian RTN4-A and RTN4-B are still elusive. In the present study, the expression of human reticulon 3 (hRTN3) in a variety of tissues was investigated. Northern blotting hybridization revealed higher expression of hRTN3 in normal brain and some endocrine-related organs such as thyroid relative to other non-endocrine organs. Twelve surgical specimens meeting the histological criteria for astrocytoma grade II, III and IV were investigated by in situ hybridization and immunohistochemical analysis, which demonstrated the overexpression of hRTN3 in astrocytoma tumor cells, while in non-cancerous brain tissues hRTN3 was mainly expressed in neurons and almost no signals in glia cells could be detected. The differential expression of hRTN3 between astrocytoma and non-cancerous tissue may provide insight into the progress of astrocytoma.

[Computing ECG based on action potential of single cardiac cell]

This paper introduces an ECG computing algorithm that computes ECG based on the action potential of single cardiac cell. Taking solid angle analysis as tool, this algorithm analyzes the field potential of a cardiac cell that connects and communicates with neighboring cells. This algorithm has been implemented in our electrophysiological model CardioAuto, which was built with extended Cellular 3.0-a cellular automata system. Algorithm and simulation results reveal that it is the transmembrane potential slope among cell group that contributes to ECG waveform generation and determines the waveform deflection. To a specific lead location, whenever cell group has a transmembrane potential slope that proximal end is higher than distal end, a downward ECG deflection is generated. Whenever cell group has a reverse transmembrane potential slope, an upward ECG deflection is generated. Whenever there is no transmembrane potential slope, ECG keeps on baseline. According to our algorithm, the significance of normal and many abnormal ECG waveforms can be analyzed and interpreted at cellular level.