Nocardioides iriomotensis sp. nov., an actinobacterium isolated from forest soil.

An actinomycete strain, designated IR27-S3(T), was isolated from a forest soil sample collected from Iriomote Island, Okinawa, Japan. Cells of the isolate were Gram-stain-positive, aerobic, non-sporulating, non-motile coccoids or short rods. The strain grew in the presence of 0-7 % (w/v) NaCl, at pH 6-8 and at 12-37 °C, with optimum growth at 30 °C. Chemotaxonomically, the strain contained LL-diaminopimelic acid as the diagnostic diamino acid and MK-8(H4) as the predominant menaquinone. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown phospholipid. The major cellular fatty acids were iso-C16:0, C17:1 cis-9, C15:0 and iso-C15:0. The DNA G+C content was 73.7 mol%. On the basis of 16S rRNA gene sequence analysis, strain IR27-S3(T) was closely related to Nocardioides mesophilus MSL-22(T) (98.1 % 16S rRNA gene sequence similarity), Marmoricola bigeumensis MSL-05(T) (97.2 %) and Nocardioides jensenii DSM 20641(T) (96.5 %). On the basis of fatty acid analysis, phylogenetic analysis and phenotypic data, the isolate should be classified in a novel species of the genus Nocardioides, for which the name Nocardioides iriomotensis sp. nov. is proposed. The type strain is IR27-S3(T) ( = NBRC 105384(T)  = KACC 14926(T)).

Nocardiopsis nikkonensis sp. nov., isolated from a compost sample.

An actinomycete strain, designated YU1183-22(T), was isolated from a compost sample collected in Nikko, Japan. The isolate formed white aerial mycelium with relatively long aerial hyphae showing chains of arthrospores. Strain YU1183-22(T) grew with 0-10 % (w/v) NaCl, at pH 6-11 and at 10-37 °C (optimum 30 °C). Strain YU1183-22(T) contained meso-diaminopimelic acid and no diagnostic sugars. The predominant menaquinones were MK-10(H(10)) and MK-10(H(8)). The polar lipids were phosphatidylcholine and phosphatidylglycerol. The major cellular fatty acids were iso-C(16 : 0), anteiso-C(17 : 0) and tuberculostearic acid. The G+C content of the DNA was 72.3 mol%. Chemotaxonomic and morphological characterization clearly demonstrated that strain YU1183-22(T) belonged to the genus Nocardiopsis. Phylogenetic analysis using 16S rRNA gene sequences showed that the isolate was closely related to Nocardiopsis salina YIM 90010(T) (98.0 % 16S rRNA gene sequence similarity), Nocardiopsis xinjiangensis YIM 90004(T) (97.9 %) and Nocardiopsis kunsanensis HA-9(T) (97.3 %). However, DNA-DNA relatedness as well as physiological and biochemical analyses showed that strain YU1183-22(T) could be differentiated from its closest phylogenetic relatives. It is proposed that this strain be classified as a representative of a novel species of the genus Nocardiopsis, with the name Nocardiopsis nikkonensis sp. nov. The type strain is YU1183-22(T) (=NBRC 102170(T) =KCTC 19666(T)).

Toll-like receptor 4 mediates the antitumor host response induced by a 55-kilodalton protein isolated from Aeginetia indica L., a parasitic plant.

A 55-kDa protein named AILb-A, isolated from the seed extract of Aeginetia indica L., a parasitic plant, induces a Th1-type T-cell response and elicits a marked antitumor effect in tumor-bearing mice. In the present study, we examined the role of Toll-like receptors (TLRs), which have been implicated in pathogen-induced cell signaling, in AILb-A-induced immune responses. In the luciferase assay using a nuclear factor (NF)-kappaB-dependent reporter plasmid, AILb-A induced NF-kappaB activation in the cells transfected with TLR4, but not with those transfected with the TLR2 gene, in a dose-dependent manner. TLR4-mediated NF-kappaB activation induced by AILb-A but not by lipopolysaccharide (LPS) was also observed under serum-free conditions. In in vitro experiments using human peripheral blood mononuclear cells, AILb-A-induced cytokine production was markedly inhibited by anti-TLR4 but not by anti-CD14 antibody, while LPS-induced, TLR4-mediated cytokine production was inhibited by anti-CD14 as well as anti-TLR4 antibodies. Cytokine production, killer cell activities, maturation of dendritic cells, phosphorylation of mitogen-activated protein kinases, and nuclear translocation of interferon-regulatory factor 3 induced by AILb-A were severely impaired in TLR4-deficient but not TLR2-deficient mice. Transfection of TLR4-deficient mouse-derived macrophages with the TLR4 expression plasmid led AILb-A to induce cytokines. Finally, the antitumor effect of AILb-A was also impaired in TLR4-deficient and TLR4-mutated mice. These findings suggest that TLR4 mediates antitumor immunity induced by the plant-derived protein AILb-A.