A detailed analysis of the leaf rolling mutant sll2 reveals complex nature in regulation of bulliform cell development in rice (Oryza sativa L.).

Bulliform cells are large, thin-walled and highly vacuolated cells, and play an important role in controlling leaf rolling in response to drought and high temperature. However, the molecular mechanisms regulating bulliform cell development have not been well documented. Here, we report isolation and characterisation of a rice leaf-rolling mutant, named shallot-like 2 (sll2). The sll2 plants exhibit adaxially rolled leaves, starting from the sixth leaf stage, accompanied by increased photosynthesis and reduced plant height and tiller number. Histological analyses showed shrinkage of bulliform cells, resulting in inward-curved leaves. The mutant is recessive and revertible at a rate of 9%. The leaf rolling is caused by a T-DNA insertion. Cloning of the insertion using TAIL-PCR revealed that the T-DNA was inserted in the promoter region of LOC_Os07 g38664. Unexpectedly, the enhanced expression of LOC_Os07 g38664 by the 35S enhancer in the T-DNA is not responsible for the leaf rolling phenotype. Further, the enhancer also exerted a long-distance effect, including up-regulation of several bulliform cell-related genes. sll2 suppressed the outward leaf rolling of oul1 in the sll2oul1 double mutant. We conclude that leaf rolling in sll2 could be a result of the combined effect of multi-genes, implying a complex network in regulation of bulliform cell development.

Association of MTHFR C677T polymorphisms and colorectal cancer risk in Asians: evidence of 12.255 subjects

OBJECTIVES: To investigate the relationship of the MTHFR polymorphisms (C677T) and the risk of CRC by meta-analysis. METHODS: Relevant literatures concerning the association between the MTHFR C677T polymorphism and the risk of CRC were searched using the electronic database PubMed, EMBASE, Cochrane and China National Knowledge Infrastructure (CNKI). Odds ratio (ORs) and 95 % confidence intervals (CIs) were determined to assess the gene-disease association using fixed or random effect models, according to the heterogeneity among included studies. RESULTS: The study shows that the MTHFR 677 TT homozygous genotype significantly decreases the risk of CRC in Asians (TT vs. CC: OR = 0.82, 95 % CI 0.73-0.92; TT vs. CT: OR = 0.84, 95 % CI 0.75-0.94; TT vs. CC+TT: OR = 0.83, 95 % CI 0.75-0.93). CONCLUSION: This meta-analysis indicated that the MTHFR 677 TT homozygous genotype decreased the risk of CRC in Asians, while the MTHFR 677 CT heterozygous genotype did not contribute to CRC susceptibility (AU)

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Association of MTHFR C677T polymorphisms and colorectal cancer risk in Asians: evidence of 12,255 subjects.

OBJECTIVES: To investigate the relationship of the MTHFR polymorphisms (C677T) and the risk of CRC by meta-analysis. METHODS: Relevant literatures concerning the association between the MTHFR C677T polymorphism and the risk of CRC were searched using the electronic database PubMed, EMBASE, Cochrane and China National Knowledge Infrastructure (CNKI). Odds ratio (ORs) and 95 % confidence intervals (CIs) were determined to assess the gene-disease association using fixed or random effect models, according to the heterogeneity among included studies. RESULTS: The study shows that the MTHFR 677 TT homozygous genotype significantly decreases the risk of CRC in Asians (TT vs. CC: OR = 0.82, 95 % CI 0.73-0.92; TT vs. CT: OR = 0.84, 95 % CI 0.75-0.94; TT vs. CC+TT: OR = 0.83, 95 % CI 0.75-0.93). CONCLUSION: This meta-analysis indicated that the MTHFR 677 TT homozygous genotype decreased the risk of CRC in Asians, while the MTHFR 677 CT heterozygous genotype did not contribute to CRC susceptibility.

Use of induction promoters to regulate hyaluronan synthase and UDP-glucose-6-dehydrogenase of Streptococcus zooepidemicus expression in Lactococcus lactis: a case study of the regulation mechanism of hyaluronic acid polymer.

AIMS: To determine the effects of the ratios of hyaluronan synthase expression level to precursor sugar UDP-GlcA biosynthesis ability on the molecular weight (MW) of hyaluronic acid (HA) in recombinant Lactococcus lactis. METHODS AND RESULTS: The genes szHasA (hyaluronan synthase gene) and szHasB (UDP-glucose-6-dehydrogenase gene) of Streptococcus zooepidemicus were introduced into L. lactis under the control of nisA promoter and lacA promoter respectively, resulting in a dual-plasmid controlled expression system. The effects of the ratios of hyaluronan synthase expression level to the precursor sugar UDP-GlcA biosynthesis ability under different induction concentration collocations with nisin and lactose on the MW of HA in recombinant L. lactis were determined. The results showed that the final weight-average molecular weight () of HA correlated with the relative ratios of HasA (hyaluronan synthase) expression level to the concentration of UDP-GlcA. CONCLUSIONS: Regulating the relative ratios of HasA expression level to the precursor sugar biosynthesis ability was an efficient method to control the size of HA. SIGNIFICANCE AND IMPACT OF THE STUDY: This study put forward a guide to establish an efficacious way to control the size of HA in fermentation.

A novel method for analysis of single ion channel signal based on wavelet transform.

A single ion channel signal was analysed by the power distribution fraction constructed by a discrete wavelet transform. Average opening time and energy distribution of the signal can be obtained directly by this method. The method can also be used when the signal is corrupted by noise. By contrast, the conventional frequency domain analysis method--power spectral density--is less effective. Power distribution fraction will therefore give more useful information in analysis of experimental ion channel signals, principally by giving values of the mean channel opening time. The method may be applied to distinguish different ion channels more efficiently and to find their reactions to drugs.

AFM study of the effect of metronidazole on surface structures of sulfate-reducing bacteria.

The effect of metronidazole (ME) on sulfate-reducing bacteria (SRB) was studied by atomic force microscopy (AFM) in this paper. Topography images of SRB cell show that after exposure to ME individual cell shape is sharply modified. Topography and phase images of SRB cell wall show that after exposure to ME not only the roughness of the cell wall increases but also the physical performance of SRB surface is changed to be uniform. AFM frictional loops show that after exposure to ME, SRB surface friction is increased remarkably.

QTL analysis for rice grain length and fine mapping of an identified QTL with stable and major effects.

Grain length in rice plays an important role in determining rice appearance, milling, cooking and eating quality. In this study, the genetic basis of grain length was dissected into six main-effect quantitative trait loci (QTLs) and twelve pairs of epistatic QTLs. The stability of these QTLs was evaluated in four environments using an F7 recombinant inbred line (RIL) population derived from the cross between a Japonica variety, Asominori, and an Indica variety, IR24. Moreover, chromosome segment substitution lines (CSSLs) harboring each of the six main-effect QTLs were used to evaluate gene action of QTLs across eight environments. A major QTL denoted as qGL-3a, was found to express stably not only in the isogenic background of Asominori but also in the recombinant background of Asominori and IR24 under multiple environments. The IR24 allele at qGL-3a has a positive effect on grain length. Based on the test of advanced backcross progenies, qGL-3a was dissected as a single Mendelian factor, i.e., long rice grain was controlled by a recessive gene gl-3. High-resolution genetic and physical maps were further constructed for fine mapping gl-3 by using 11 simple sequence repeat (SSR) markers designed using sequence information from seven BAC/PAC clones and a BC4F2 population consisting of 2,068 individuals. Consequently, the gl-3 gene was narrowed down to a candidate genomic region of 87.5 kb long defined by SSR markers RMw357 and RMw353 on chromosome 3, which provides a basis for map-based cloning of this gene and for marker-aided QTL pyramiding in rice quality breeding.

[Clinical trial on the effects of shikonin mixture on later stage lung cancer].

The shikonin mixture was used for 19 cases of later-stage lung cancer who were not the candidates for operation, radiotherapy and chemotherapy. The clinical observation showed that shikonin mixture could inhibit the growth of lung cancer and improve the immune function of the body. The tumors were reduced over 25% in diameter. The effective rate was 63.3%, remission rate 36.9%, survival rate of one year 47.3%. The intermedium survival period was about 10 months, including adenocarcinoma 10 months, squamous carcinoma 12 months. After treatment the life quality of patients were greatly improved. The patients got better appetite and their body weights were increased. They could manage themselves in daily life. The Karnofsky scores were enhanced by 20. The authors also observed that shikonin mixture could relieve such symptoms as cough, bloody sputum and chest pain caused by lung cancer. The levels of cells and interleukin-2 were increased (P less than 0.001). It had no harmful effects on peripheral blood picture, heart, kidney and liver. Shikonin mixture is safe and effective for later-stage cancer.