Summary• A total of 191 rhizobial isolates from the root nodules of three geographically separate populations of the invasive plant Mimosa pigra in Taiwan were examined using amplified rDNA restriction analysis, 16S rDNA sequences, protein profiles and ELISA. Of these, 96% were identified as Burkholderia and 4% as Cupriavidus taiwanensis .• The symbiosis-essential genes nodA and nifH were present in two strains of Burkholderia (PAS44 and PTK47), and in one of C. taiwanensis (PAS15). All three could nodulate M. pigra .• Light and electron microscopy studies with a green fluorescent protein transconjugant variant of strain PAS44 showed the presence of fluorescent bacteroids in M. pigra nodules. These bacteroids expressed the nifH protein, hence this is the first confirmation that Burkholderia is a genuine symbiont of legume nodules.• The predominance of Burkholderia in Taiwanese M. pigra suggests that this species may have brought its symbionts from its native South America, rather than entering into association with the Taiwanese Mimosa symbiont C. taiwanensis which so successfully nodulates Mimosa pudica and Mimosa diplotricha .

Stimulation of macrophages to lyse tumor cells is a property common to lipopolysaccharide (LPS) extracted from a variety of smooth and rough bacterial strains by several different preparative procedures. The relationship between macrophage stimulation and the structural characteristics of LPS is defined. In protein-free LPS, lipid A bears the stimulatory signal which results in the differentiation of elicited macrophages into killer cells. The polysaccharide moiety is neither stimulatory itself nor does it block the activity of complete LPS on macrophages. Extraction of LPS by the butanol or Boivin procedures produces preparations in which LPS is complexed through its lipid A moiety to a protein rich component, LAP. Isolated LAP delivers a macrophage differentiation signal which is independent of lipid A. The presence of these two structurally distinct constituents in the cell walls of gram-negative bacteria broadens the biological environments in which they can stimulate macrophages in vivo.

A new homoerythrina alkaloid, C-3-epi-wilsonione (1), a new tetraflavonoid, taiwanhomoflavone C (2), and a new stereoisomer of desmethylcephalotaxinone (3) have been isolated from the leaves and heartwood of Cephalotaxus wilsoniana, respectively. The structures were elucidated by spectroscopic methods. Compound 1 showed cytotoxic activity against a number of human cancer cell lines in vitro.

A novel phenolic compound containing an oxepine ring, artocarpol I (1), and a new biphenylpropanoid, artocarpol J (2), were isolated from the root bark of Artocarpus rigida. The structures, including relative configurations, were elucidated by spectroscopic data. Compound 1 and artocarpol J peracetate (3) strongly inhibited in a concentration-dependent manner the formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB)-stimulated superoxide anion formation in neutrophils with IC 50 values of 17.1 AE 0.40 and 20.5 AE 2.60 mm, respectively. Biogenetically, all the novel phenolic compounds isolated from this plant seem to be derived from stilbene.1. Introduction. ± Previously, we reported the isolation of a series of phenolic compounds with a new skeleton from the root barks of Formosan Artocarpus rigida (Moraceae) [1 ± 4]. These compounds were different from those of the same plant grown in Indonesia which were reported by Hano et al.[5] [6]. Further examination of the CHCl 3 extract of the root barks resulted in the isolation of two new compounds, artocarpol I (1) and J (2). Artocarpol A strongly inhibited superoxide anion formation in phorbal 12-myristate 13-acetate (PMA) stimulated rat neutrophils and significantly inhibited tumor necrosis factor-a (TNF-a) formation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells [1]. Artocarpol C strongly inhibited the release of bglucuronidase and histamine from mast cell degranulation caused by compound 48/80 and also showed strongly inhibitory effect on the formyl-Met-Leu-Phe(fMLP)/ cytochalasin B(CB)-stimulated superoxide anion formation in neutrophils [4]. In the present paper, the structure elucidation of 1 and 2 from this plant, and the antiinflammatory activities of 1 and artocarpol J peracetate (3) are reported.