The key to plant survival under NaCl salt stress is maintaining a low Na+ level or Na+/K+ ratio in the cells. A population of recombinant inbred lines (RILs, F2∶9) derived from a cross between the salt-tolerant japonica rice variety Jiucaiqing and the salt-sensitive indica variety IR26, was used to determine Na+ and K+ concentrations in the roots and shoots under three different NaCl stress conditions (0, 100 and 120 mM NaCl). A total of nine additive QTLs were identified by QTL Cartographer program using single-environment phenotypic values, whereas eight additive QTLs were identified by QTL IciMapping program. Among these additive QTLs, five were identified by both programs. Epistatic QTLs and QTL-by-environment interactions were detected by QTLNetwork program in the joint analyses of multi-environment phenotypic values, and one additive QTL and nine epistatic QTLs were identified. There were three epistatic QTLs identified for Na+ in roots (RNC), three additive QTLs and two epistatic QTLs identified for Na+ in shoots (SNC), four additive QTLs identified for K+ in roots (RKC), four additive QTLs and three epistatic QTLs identified for K+ in shoots (SKC) and one additive QTL and one epistatic QTL for salt tolerance rating (STR). The phenotypic variation explained by each additive, epistatic QTL and QTL×environment interaction ranged from 8.5 to 18.9%, 0.5 to 5.3% and 0.7 to 7.5%, respectively. By comparing the chromosomal positions of these additive QTLs with those previously identified, five additive QTLs, qSNC9, qSKC1, qSKC9, qRKC4 and qSTR7, might represent novel salt tolerance loci. The identification of salt tolerance in selected RILs showed that a major QTL qSNC11 played a significant role in rice salt tolerance, and could be used to improve salt tolerance of commercial rice varieties with marker-assisted selection (MAS) approach.

Curcumin, which is extracted from the plant Curcuma longa, has been used in the therapeutic arsenal for clinical oncology. Curcumin has chemopreventive and antitumoral activities against some aggressive and recurrent cancers. The expressions and activities of various proteins, such as inflammatory cytokines and enzymes, transcription factors, and gene-products linked with cell survivals and proliferation, can be modified by curcumin. Moreover, curcumin decreases the toxic effect of mitomycin C. Though curcumin has shown highly cytotoxic to some cancer cell lines, curcumin is insoluble and instable in water. The solubility of curcumin could be enhanced by utilizing the solubilizing properties of rubusoside. In addition, the selective delivery of synthetic analogs or nanotechnology-based formulations of curcumin to tumors may improve the chemopreventive and chemotherapeutic effects. The focus of this short review is to describe how curcumin participates in antitumor processes in breast cancer cells.

Natural product extracts are a rich source of small molecules that display antitumor activity. Cantharidin, in the form of the dried body of the Chinese blister beetles: Mylabris phalerata or M. cichorii, displays antitumor activity and induces apoptosis in many types of tumor cells. Cantharidin has been used as an anticancer agent by the Chinese for the treatment of hepatoma and oesophageal carcinoma for a long time. Although cantharidin is a natural toxin that possesses potent anti-tumor properties, its clinical application is limited due to severe side-effects and highly toxic nature. Therefore, some modified cantharidin analogues are synthesized chemically in order to achieve a comparable antitumour property to the mother compound but simultaneously produce a less toxic effect on non-cancer cells. In recent years, based on the structure of cantharidin, there has been intense interest in developing potent and selective inhibitors of PP1 and PP2A on tumour cells. Though numerous analogues of cantharidin have been synthesized and researched with tumour cell lines, there is little success on clinical application because of the potential toxicity of cantharidin derivates. The focus of this review is to describe how cantharidin and cantharidin derivates participate in antitumour processes in tumour cells, and discuss the molecular mechanisms of cantharidin and cantharidin derivates on tumour cells.

No abstract

Bacterial leaf steak (BLS) is one of the most destructive diseases in rice. Studies have shown that BLS resistance in rice is quantitatively inherited, controlled by multiple quantitative trait loci (QTLs). A QTL with relatively large effect, qBlsr5a, was previously mapped in a region of ∼380 kb on chromosome 5. To fine map qBlsr5a further, a set of overlapping sub-chromosome segment substitution lines (sub-CSSLs) were developed from a large secondary F2 population (containing more than 7000 plants), in which only the chromosomal region harboring qBlsr5a was segregated. By genotyping the sub-CSSLs with molecular markers covering the target region and phenotyping the sub-CSSLs with artificial inoculation, qBlsr5a was delimited to a 30.0-kb interval, in which only three genes were predicted. qRT-PCR analysis indicated that the three putative genes did not show significant response to the infection of BLS pathogen in both resistant and susceptible parental lines. However, two nucleotide substitutions were found in the coding sequence of gene LOC_Os05g01710, which encodes the gamma chain of transcription initiation factor IIA (TFIIAγ). The nucleotide substitutions resulted in a change of the 39th amino acid from valine (in the susceptible parent) to glutamic acid (in the resistant parent). Interestingly, the resistant parent allele of LOC_Os05g01710 is identical to xa5, a major gene resistant to bacterial leaf blight (another bacterial disease of rice). These results suggest that LOC_Os05g01710 is very possibly the candidate gene of qBlsr5a.