The spikelet is a unique inflorescence structure in grass. The molecular mechanisms behind the development and evolution of the spikelet are far from clear. In this study, a dominant rice mutant, lateral florets 1 (lf1), was characterized. In the lf1 spikelet, lateral floral meristems were promoted unexpectedly and could generally blossom into relatively normal florets. LF1 encoded a class III homeodomain-leucine zipper (HD-ZIP III) protein, and the site of mutation in lf1 was located in a putative miRNA165/166 target sequence. Ectopic expression of both LF1 and the meristem maintenance gene OSH1 was detected in the axil of the sterile lemma primordia of the lf1 spikelet. Furthermore, the promoter of OSH1 could be bound directly by LF1 protein. Collectively, these results indicate that the mutation of LF1 induces ectopic expression of OSH1, which results in the initiation of lateral meristems to generate lateral florets in the axil of the sterile lemma. This study thus offers strong evidence in support of the "three-florets spikelet" hypothesis in rice.lateral floret | three-florets spikelet | evolution | yield | rice F lower development is a key process in the reproduction of angiosperms. Under suitable conditions, flowering signals are transmitted to shoot apical meristems (SAMs), which are transformed first into inflorescence meristems (IMs). Floral meristems (FMs) are then initiated on the top and/or lateral domains of the IMs and subsequently transformed into the four whorls of floral organs. The spikelet is a unique unit of inflorescence architecture in grasses and consists of a pair of glumes and a fixed or variable number of florets. Some grassspecific genes are involved in regulating spikelet development. For example, FRIZZY PANICLE (FZP) functions in regulating spikelet meristem (SM) identity in rice. In the fzp mutant, axillary meristems (AMs) are formed instead of FMs, and these then develop into higher-order branches (1). Three genes that encode members of the AP2/ERF superfamily, SUPERNUMERARY BRACT (SNB), INDETERMINATE SPIKELET 1 (OsIDS1), and MULTI-FLORETS SPIKELET 1 (MFS1), are involved in regulating spikelet determinacy in rice (2, 3). In these mutants, the transition from SM to FM is delayed, and extra organs or florets are produced. However, our knowledge about the details of spikelet development in rice remains limited.In most members of Oryzeae, the spikelet is composed of one pair of rudimentary glumes, one pair of sterile lemmas, and one terminal fertile floret, which consists of one pair of hulls (lemma and palea) and inner floral organs (4). Regarding the origin of the sterile lemmas, the "three-florets spikelet" hypothesis proposes that the putative ancestor of the rice spikelet contained two lateral florets in addition to a terminal fertile floret. Subsequently, the lemmas of the two lateral florets degenerated into sterile lemmas, and the inner floral organs and palea degenerated markedly and disappeared during evolution (5). In recent years, several reports have supported this hypot...

There are three isoforms of dimeric nitric oxide synthases (NOS) that convert arginine to citrulline and nitric oxide. Inducible NOS is implicated in numerous inflammatory diseases and, more recently, in neuropathic pain states. The majority of existing NOS inhibitors are either based on the structure of arginine or are substrate competitive. We describe the identification from an ultra high-throughput screen of a novel series of quinolinone small molecule, nonarginine iNOS dimerization inhibitors. SAR studies on the screening hit, coupled with an in vivo lipopolysaccharide (LPS) challenge assay measuring plasma nitrates and drug levels, rapidly led to the identification of compounds 12 and 42--potent inhibitors of the human and mouse iNOS enzyme that were highly selective over endothelial NOS (eNOS). Following oral dosing, compounds 12 and 42 gave a statistical reduction in pain behaviors in the mouse formalin model, while 12 also statistically reduced neuropathic pain behaviors in the chronic constriction injury (Bennett) model.

Chinese toad, Bufo bufo gargarizans, is frequently found in rice fields, muddy ponds, wetlands and other aquatic ecosystems in China. Because of its habitat, it has many chances of being exposed to pesticides, such as acetochlor, butachlor, chlorimuron-ethyl, and paraquat, which are extensively used in rice or cereal fields. Amphibians may serve as model organisms for determining the genotoxic effects of pollutants contaminating these areas. In the present study DNA damage was evaluated in the Chinese toad using the comet assay, as a potential tool for the assessment of ecogenotoxicity. The first step was to determine the acute toxicity of the above-mentioned herbicides. In acute tests, tadpoles were exposed to a series of relatively high concentrations of acetochlor, butachlor, chlorimuron-ethyl, and paraquat for 96 h. The LC(50 )(96 h) of acetochlor, butachlor, chlorimuron-ethyl and paraquat were measured as 0.76, 1.32, 20.1 and 164 mg l(-1), respectively. Also, negative effects on the behavior of tadpoles were observed with acetochlor, butachlor, and paraquat. Secondly, the comet assay was used for detecting DNA damage in Chinese toad tadpoles exposed to sublethal concentrations of four herbicides. Significant (P < 0.05) concentration-dependent increase in DNA damage (as indicated by tail length, tail moment, olive tail moment) were observed from erythrocytes of tadpoles exposed to sublethal concentrations of acetochlor, butachlor, paraquat, and methyl methanesulfonate, except chlorimuron-ethyl. To our knowledge, this is the first report describing the use of Bufo bufo gargarizans for genotoxicity assessment of herbicides.

A modular system for high‐output solid‐phase combinatorial synthesis has been designed and developed. The system employs three technological innovations to achieve its high efficiency and reliability: (1) application of microreactors as the reaction units in solid‐phase synthesis; (2) use of radiofrequency tagging as the non‐chemical tracking method; and (3) development of the directed sorting technology for split & pool synthesis. The system has been successfully applied in the synthesis of compound libraries of several hundred to several thousand compounds in multi‐milligrams per compound quantity by many organizations. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng (Comb Chem) 71:44–50, 2000.