Biological species ofArmillaria and their mycoparasitic associations withRhodophyllus abortivus in Hokkaido

Specimens of basidiomes and/or rhizomorphs ofArmillaria mellea complex and basidiomes ofRhodophyllus abortivus, developing on the same decaying stumps or stems of forest trees, were collected in three forests in Hokkaido. Normal basidiomes ofR. abortivus were found near to, but free from, the rhizomorphs and/or basidiomes ofArmillaria, while abnormal basidiomes, as carpophoroid forms, were developed on the rhizomorphs ofArmillaria. Of three mycoparasiticArmillaria isolates found withR. abortivus, one was identified asA. gallica and two asA. jezoensis. The isolates ofR. abortivus showed excellent mycelial growth and rhizomorph formation on PDA. However, on MDA, RMDA and BMDA, they showed poor aerial mycelia growth and no rhizomorphs. In the contrapositional cultures, the growth ofA. gallica was completely inhibited byR. abortivus on PDA but only slightly inhibited on MDA and RMDA. On the other hand, mutual inhibition at a distance was observed on BMDA. The mycelial growth and rhizomorph formation inA. jezoensis were severely inhibited by the colony ofR. abortivus on PDA, but only slightly inhibited on MDA. On RMDA and BMDA, the colonies of twoArmillaria species andR. abortivus showed mutual inhibition at a distance and apparent rhizomorph formation by bothArmillaria species.     

Inhibition of Taq DNA polymerase by seaweed extracts from British Columbia, Canada and Korea

Fifty-nine species of marine macrophytes from the coasts of British Columbia, Canada and Korea have been screened for the presence of PCR inhibitors, namely inhibitors of Taq DNA polymerase. Eleven of the species displayed some inhibitor activity. At the concentration of 5 μg of methanol extract in 25μL reaction mixture of PCR containing 1.5 unit of Taq DNA polymerase, one (Ulva sp.) of 8 Chlorophyta, eight (Colpomenia bullosa, Ecklonia cava, Endarachne binghamiae, Fucus distichus, Hizikia fusiformis, Sargassum confusum, Sargassum sagamianum, and Sargassum thunbergii) of 28 Phaeophyta, and one (Symphyocladia latiuscula) of 34 Rhodophyta showed inhibition in PCR amplification. In the case of the water extract, two (Cladophora columbiana, Ulva sp.) Chlorophyta, seven (Endarachne binghamiae, Fucus distichus, Hizikia fusiformis, Sargassum confusum, Sargassum sagamianum, Sargassum horneri, Scytosiphon dotyi) Phaeophyta, no Rhodophyta and one (Phyllospadix scouleri) seagrass showed inhibition in PCR amplification. the methanol fraction of Sargassum confusum and the water fraction of Fucus gardneri (mid–intertidal) have been found to inhibit PCR at level as low as 0.5 μg in 25μL of PCR reaction mixture. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mutational analysis of the three cysteines and active-site aspartic acid 103 of ketosteroid isomerase from Pseudomonas putida biotype B.

In order to clarify the roles of three cysteines in ketosteroid isomerase (KSI) from Pseudomonas putida biotype B, each of the cysteine residues has been changed to a serine residue (C69S, C81S, and C97S) by site-directed mutagenesis. All cysteine mutations caused only a slight decrease in the k(cat) value, with no significant change of Km for the substrate. Even modification of the sulfhydryl group with 5,5'-dithiobis(2-nitrobenzoic acid) has almost no effect on enzyme activity. These results demonstrate that none of the cysteines in the KSI from P. putida is critical for catalytic activity, contrary to the previous identification of a cysteine in an active-site-directed photoinactivation study of KSI. Based on the three-dimensional structures of KSIs with and without dienolate intermediate analog equilenin, as determined by X-ray crystallography at high resolution, Asp-103 was found to be located within the range of the hydrogen bond to the equilenin. To assess the role of Asp-103 in catalysis, Asp-103 has been replaced with either asparagine (D103N) or alanine (D103A) by site-directed mutagenesis. For D103A mutant KSI there was a significant decrease in the k(cat) value: the k(cat) of the mutant was 85-fold lower than that of the wild-type enzyme; however, for the D103N mutant, which retained some hydrogen bonding capability, there was a minor decrease in the k(cat) value. These findings support the idea that aspartic acid 103 in the active site is an essential catalytic residue involved in catalysis by hydrogen bonding to the dienolate intermediate.     

A Novel Electrochemically Active and Fe(III)-reducing Bacterium Phylogenetically Related to Clostridium butyricum Isolated from a Microbial Fuel Cell

An obligatory anaerobic bacterium was isolated from a mediator-less microbial fuel cell using starch processing wastewater as the fuel and designated as EG3. The isolate was Gram-positive, motile and rod (2.8–3.0 μm long, 0.5–0.6 μm wide). The partial 16S rRNA gene sequence and analysis of the cellular fatty acids profile suggested that EG3 clusters with Clostridium sub-phylum and exhibited the highest similarity (98%) with Clostridium butyricum. The temperature and pH optimum for growth were 37°C and 7.0, respectively. The major products of glucose and glucose/Fe(O)OH metabolism were lactate, formate, butyrate, acetate, CO₂and H₂. Growth was faster at the initial phase and the cell yield was higher when the medium was supplemented with Fe(O)OH than without Fe(O)OH. These results suggest that Fe(III) ion is utilised as an electron sink. Cyclic voltammetry showed that Clostridium butyricum EG3 cells were electrochemically active. It is a novel characteristic of strict anaerobic Gram-positive bacteria.     

Tissue-selective regulation of protein homeostasis and unfolded protein response signalling in sporadic ALS

Amyotrophic lateral sclerosis (ALS) is a disorder that affects motor neurons in motor cortex and spinal cord, and the degeneration of both neuronal populations is a critical feature of the disease. Abnormalities in protein homeostasis (proteostasis) are well established in ALS. However, they have been investigated mostly in spinal cord but less so in motor cortex. Herein, we monitored the unfolded protein (UPR) and heat shock response (HSR), two major proteostasis regulatory pathways, in human post-mortem tissue derived from the motor cortex of sporadic ALS (SALS) and compared them to those occurring in spinal cord. Although the UPR was activated in both tissues, specific expression of select UPR target genes, such as PDIs, was observed in motor cortex of SALS cases strongly correlating with oligodendrocyte markers. Moreover, we found that endoplasmic reticulum-associated degradation (ERAD) and HSR genes, which were activated predominately in spinal cord, correlated with the expression of neuronal markers. Our results indicate that proteostasis is strongly and selectively activated in SALS motor cortex and spinal cord where subsets of these genes are associated with specific cell type. This study expands our understanding of convergent molecular mechanisms occurring in motor cortex and spinal cord and highlights cell type–specific contributions.     

Repellent efficacy of essential oils and plant extracts against Tribolium castaneum and Plodia interpunctella

This study was conducted to investigate the repellent efficacy of essential oils (Origanum vulgare, Pimpinella anisum, and Tanacetum cinerariifolium) and four plant extracts (Agastache rugosa, Capsicum annuum, Citrus reticulata, and Ginkgo biloba) against Tribolium castaneum (adults and larvae) and Plodia interpunctella (larvae). Gas chromatography/mass spectrometry analysis revealed the presence of carvacrol, anethole, and jasmolin I as the predominant constituent in O. vulgare, P. anisum, and T. cinerariifolium, respectively. Furthermore, ethyl hexopyranoside, 9,12‐octadecadienoic acid, cyclopentanol, and 2‐cresol were identified in A. rugosa, C. annuum, C. reticulata, and G. biloba, respectively. The repellent efficacy of each essential oil, plant extract, and the combination of oils was evaluated using a specially designed cylinder trap for 120 h. Among the three oils, O. vulgare and T. cinerariifolium had greatest repellent efficacy against P. interpunctella larvae. T. cinerariifolium exhibited effective repellence against the adults and larvae of T. castaneum. Therefore, O. vulgare (O) and T. cinerariifolium (T) were selected for further investigation of combined effects. Two essential oils were mixed in three different ratios of OT1 (1:3), OT2 (1:1), and OT3 (3:1). The repellent efficacies of OT1 and OT2 against the adults of T. castaneum were significantly greater than that of OT3. OT1 was effective against the larvae of T. castaneum, whereas OT2 was effective against the larvae of P. interpunctella. OT1 enhanced the repellent efficacy by approximately five times against larvae of T. castaneum, compared with that of T. cinerariifolium. Overall, OT1 was selected as the best repellent substance against all the tested insects.     

Adhaeribacter soli sp. nov., a bacterium isolated from soil in Korea

Archives of Microbiology - Strain MA2T was isolated from a soil sample from Gijang-gun, Busan in Korea. The strain, a Gram-stain-negative aerobic bacterium, is non-motile, ovoid- or rod-shaped,...