Antibacterial activity of berberine-NorA pump inhibitor hybrids with a methylene ether linking group

Conjugation of the NorA substrate berberine and the NorA inhibitor 5-nitro-2-phenyl-1H-indole via a methylene ether linking group gave the 13-substituted berberine-NorA inhibitor hybrid, 3. A series of simpler arylmethyl ether hybrid structures were also synthesized. The hybrid 3 showed excellent antibacterial activity (MIC Staphylococcus aureus, 1.7 μM), which was over 382-fold more active than the parent antibacterial berberine, against this bacterium. This compound was also shown to block the NorA efflux pump in S. aureus.     

Mapping of Rice Rf Gene by Bulked Line Analysis

A method, bulked line analysis (BLA), was developed for identificationof the RFLP markers associated with a target gene. Instead ofsegregating progenies, conventional lines sharing the same traitwere bulked by the BLA method. This method is an alternativeapproach to the identification of DNA markers linked with atarget gene. A major advantage of this method is time-savingfor genetic stock development. The advantage is very significantfor organisms having a long generation period. This method hasbeen tested by using fertility restoration of rice cytoplasmicmale sterility of wild abortive type as a target trait. A fertility-restoringgene was successfully identified by linkage with RFLP markers.This gene was mapped in the middle of the long arm of chromosome10 of the rice genome.     

Quantitative trait loci associated with leaf and neck blast resistance in recombinant inbred line population of rice (Oryza sativa).

Blast is an economically important disease of rice. To map genes controlling blast resistance, recombinant inbred lines (RIL) were developed from Khao Dawk Mali 105, an aromatic, blast-susceptible cultivar and the blast resistance donor, CT 9993-5-10-M (CT). A linkage map encompassing 2112 cM was constructed from 141 RILs using 90 restriction fragment length polymorphisms (RFLPs) and 31 simple sequence repeats (SSR). Virulent isolates of blast fungus were identified by screening differential host sets against 87 single-spore isolates collected from the north and northeast of Thailand. Fifteen virulent blast isolates were selected for leaf blast screening. Neck blast was evaluated both under natural conditions and controlled inoculations. Quantitative trait loci (QTLs) for broad resistance spectrum (BRS) to leaf blast were located on chromosomes 7 and 9. In particular, the QTL(ch9) was mapped near the Pi5(t) locus. The QTL(ch7) was located close to a previously mapped partial resistance QTL. Both loci showed significant allelic interaction. Genotypes having CT alleles at both QTL(ch7) and QTL(ch9) were the most resistant. Two neck-blast QTLs were mapped on chromosomes 5 and 6. The inconsistent map locations between the leaf and neck blast QTLs indicate the complexity of fixing both leaf and neck blast resistance. The coincidence of BRS and field resistance QTLs on chromosome 7 supports the idea that BRS may reflect the broad resistance spectrum to leaf blast in rice. These findings laid the foundation for the development of a marker-assisted scheme for improving Khoa Dawk Mali 105 and the majority of aromatic Thai rice varieties that are susceptible to blast.     

Exogenous 7,8-dihydro-8α-20-hydroxyecdysone application improves antioxidative enzyme system,photosynthesis, and yield in rice under high-temperature condition

7,8-Dihydro-8α-20-hydroxyecdysone (DHECD) has biological activity similar to brassinosteroids. In this study, we investigated the role of DHECD on the antioxidative enzyme activity and photosynthetic performance of rice subjected to high-temperature conditions. DHECD at either 1 or 10 µM was used as a foliar application to rice leaves at 23 days after sowing, and then, at 31 days after sowing, rice plants were moved to a heat chamber at 40/30 °C day/night for 9 days. Application of DHECD significantly increased the activities of the antioxidative enzymes: superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase. The results of this study provide the first direct evident for DHECD-elevated antioxidative enzyme activity and decreased lipid peroxidation, which possibly induced thermotolerance in rice plants. Furthermore, DHECD was effective in increasing the net photosynthetic rate, stomatal conductance, and water use efficiency, as well as increasing the maximal quantum efficiency of photosystem II and decreasing non-photochemical quenching. Thus, enhancement of photosynthesis by DHECD application resulted in a high grain yield for rice plants subjected to high-temperature conditions.     

A PCR-based marker for a locus conferring aroma in vegetable soybean (<Emphasis Type="Italic">Glycine max</Emphasis> L.)

Vegetable soybean (Glycine max L.) is an important economic and nutritious crop in South and Southeast Asian countries and is increasingly grown in the Western Hemisphere. Aromatic vegetable soybean is a special group of soybean varieties that produce young pods containing a sweet aroma, which is produced mainly by the volatile compound 2-acetyl-1-pyrroline (2AP). Due to the aroma, the aromatic vegetable soybean commands higher market prices and gains wider acceptance from unfamiliar consumers. We have previously reported that the GmAMADH2 gene encodes an AMADH that regulates aroma (2AP) biosynthesis in soybeans (Arikit et al. 2010). A sequence variation involving a 2-bp deletion in exon 10 was found in this gene in all investigated aromatic varieties. In this study, a codominant PCR-based marker for the aroma trait in soybeans was designed based on the 2-bp deletion in GmAMADH2. The marker was verified in five aromatic and five non-aromatic varieties as well as in F₂ soybean population segregating for aroma. The aromatic genotype with the 2-bp deletion was completely associated with the five aromatic soybean varieties as well as the aromatic progeny of the F₂ population with seeds containing 2AP. Similarly, the non-aromatic genotype was associated with the five non-aromatic varieties and non-aromatic progeny. The perfect co-segregation of the marker genotypes and aroma phenotypes confirmed that the marker could be efficiently used for molecular breeding of soybeans for aroma.     

Abietane Diterpenes from Hyptis suaveolens

Investigation of the constituents of the whole plant of Hyptis suaveolens led to the isolation of three new abietane diterpenes, isosuaveolic acid ( 1 ), 8α,9α‐epoxysuaveolic acid ( 2 ), and 14‐O‐methylsuaveolic acid ( 3 ), together with eleven known compounds. The structures of 1 – 3 were established by spectroscopic methods and chemical correlations. Some isolates were tested for their antimycobacterial and cytotoxic activities.