Genes that encode products containing a NAC domain, such as NO APICAL MERISTEM (NAM) in petunia, CUP-SHAPED COTYLEDON2 (CUC2) and NAP in Arabidopsis thaliana, have crucial functions in plant development. We describe here molecular aspects of the OsNAC genes that encode proteins with NAC domains in rice (Oryza sativa L.). Sequence analysis revealed that the NAC genes in plants can be divided into several subfamilies, such as the NAM, ATAF, and OsNAC3 subfamilies. In rice, OsNAC1 and OsNAC2 are classified in the NAM subfamily, which includes NAM and CUC2, while OsNAC5 and OsNAC6 fall into the ATAF subfamily. In addition to the members of these subfamilies, the rice genome contains the NAC genes OsNAC3, OsNAC4 (both in the OsNAC3 subfamily), OsNAC7, and OsNAC8. These results and Southern analysis indicate that the OsNAC genes constitute a large gene family in the rice genome. Each OsNAC gene is expressed in a specific pattern in different organs, suggesting that this family has diverse and important roles in rice development.

Interferon-gamma-inducing factor/interleukin-18 is a novel cytokine that reportedly augments natural killer (NK) activity in human and mouse peripheral blood mononuclear cell cultures in vitro and has recently been designated IL-18. In this study, IL-18 exhibited significant antitumor effects in BALB/c mice challenged intraperitoneally (i.p.) with syngeneic Meth A sarcoma when administered i.p. on days 1, 2 and 3 after challenge. Intravenous (i.v.) administration also induced antitumor effects in the tumor-bearing mice; however, subcutaneous (s.c.) administration did not. When mice were twice pretreated with 1 microg IL-18 3 days and 6 h before tumor challenge, all mice survived whereas control mice died within 3 weeks of challenge. Inhibitory effects on Meth A cell growth in vitro were not observed with either IL-18 or interferon gamma. The effects of IL-18 pretreatment were abrogated by abolition of NK activity after mice had been injected with anti-asialo GM1 antibody 48 h before and, 24 h and 72 h after tumor challenge. Mice pretreated with IL-18 and surviving tumor challenge resisted rechallenge with Meth A cells but could not reject Ehrlich ascites carcinoma, and spleen cells from the resistant mice, but not control mice, exhibited cytotoxic activity against Meth A cells in vitro after restimulation with mitomycin C-treated Meth A cells for 5 days. The effector cells in the spleen cell preparations from resistant mice appear to be CD4+ cells because cytolytic activity was significantly inhibited after depletion of this subset by monoclonal antibodies and complement. In conclusion, IL-18 exhibits in vivo immunologically (primarily NK) mediated antitumor effects in mice challenged with syngeneic Meth A sarcoma and induces immunological memory and the generation of cytotoxic CD4+ cells.

Bacteriocin plasmid pPD1 in Enterococcus faecalis encodes a mating response to recipient-produced sex pheromone cPD1. Once a recipient acquires pPD1, transconjugants apparently shut off cPD1 activity in broth culture and no longer behave as recipients for pPD1. This event is performed by synthesis of the pheromone inhibitor iPD1 and also by repression of cPD1 production, the so-called ''pheromone shutdown.'' A 5.4-kb EcoRV-HincII segment of pPD1, which expressed iPD1 in Escherichia coli, was sequenced and found to be organized as traC-traB-traA-ipd; each open reading frame is analogous to that found in other pheromone plasmids, pAD1 and pCF10, and thus is designated in accordance with the nomenclature in pAD1. The ipd gene encodes a peptide consisting of 21 amino acids, in which the C-terminal eight residues correspond to iPD1. The putative TraC product has a strong similarity to oligopeptide-binding proteins found in other bacterial species, as do pheromone-binding proteins of pCF10 and pAD1. A strain carrying traC-disrupted pPD1 required a concentration of cPD1 fourfold higher than that needed by the wild-type strain for induction of sexual aggregation. These results suggest that the TraC product contributes to pheromone sensitivity as a pheromonebinding protein. A strain transformed with traB-disrupted pPD1 produced a high level of cPD1 similar to that produced by plasmid-free recipients and underwent self-induction. Thus, the TraB product contributes to cPD1 shutdown.Certain plasmids in Enterococcus faecalis encode a mating response to small-peptide sex pheromones secreted from potential recipient cells (for recent reviews, see references 4 and 5). The sex pheromone induces a surface adhesin, termed aggregation substance, which leads to sexual aggregation of recipient and donor cells (9,12,13,47). The formation of the mating aggregate facilitates the high-frequency transfer of plasmids in a liquid medium.The plasmid-free recipient secretes multiple pheromones (10). A given pheromone (cX) specifically activates the conjugal transfer system of the corresponding plasmid (pX). Once a recipient acquires the plasmid, it becomes a donor; however, it continues to behave as a recipient for other plasmids. The transconjugant donor no longer detectably secretes that pheromone, while the activity of other pheromones continues to be elaborated. Two kinds of genetic function can explain the disappearance of pheromone activity. One is the production of a peptide inhibitor (iX) competitive with the pheromone, and the other is repression of pheromone production, a so-called ''pheromone shutdown.'' To address this notion, we have developed a reverse-phase high-pressure liquid chromatography (HPLC) assay enabling us to quantitate absolute pheromone and inhibitor titers in the donor supernatant, where the pheromone and inhibitor coexist (33,35). The inhibitor data showed that the inhibitors iAD1 (30), iPD1 (31), iCF10 (35), and iAM373 (34) exist in the culture broth of donor cells carrying the corresponding plasmid, consistent ...

Nine Spanish olive oils, including three each of virgin (pressed oil), refined virgin, and B‐residue (solvent‐extracted pomace oil) oils from different commercial sources, have been analyzed for their unsaponifiable matter (USM). Four sterolic fractions separated from the oils have been analyzed by preparative thin‐layer chromatography (TLC); these fractions are triterpene alcohols, 4‐methylsterols, sterols and triterpene dialcohols. The compositions of the four sterolic fractions were determined as their acetates by gas‐liquid chromatography (GLC) on an OV‐17 glass capillary column. Identification of each component was carried out by argentation TLC, GLC and combined gas chromatography‐mass spectrometry (GC‐MS); 44 components were identified, of which four: 24‐methylene‐31‐nor‐9(11)‐lanostenol, 24‐methyl‐31‐nor‐E‐23‐dehydrocycloartanol, 24‐ethyl‐E‐23‐dehydrolophenol and 5,E‐23‐stigmastadienol, were considered to be new sterols from natural sources. Several characteristics, including the content of triteterpene dialcohols in the USM and that of C‐24(28) unsaturated sterols in each of the four sterolic fractions, which can be used to distinguish between virgin and B‐residue olive oils, were observed.