A manganese-oxidizing fungus was isolated from a hot spring in Japan. The fungus was increasingly effective at oxidizing Mn(II) ions as the concentration of organic carbon sources in the growth medium was decreased. The fungus oxidized 50 ppm of Mn(II) ions within 160 h in a pH 7.3 medium at 25jC. The presence of carbon fiber shortened the time to 80 h, and promoted steady oxidation. The oxidation products were identified by XPS and XRD to be poorly crystallized and amorphous MnO 2 , both with and without the fiber. These results suggest that the fiber participates in kinetically limited oxidation. The fungus was entangled with and clung to the fibers, and the oxidized Mn species accumulated on the fungus. Similarly shaped polyethylene telephthalate fiber did not enhance the oxidation, nor was adhesion of the fungus observed. Although the mechanism is still unknown, the present work shows that removal of Mn from solution through the precipitation and accumulation of Mn-oxides on the fungus in the presence of carbon fiber is a promising improvement for water treatment. B 2004 Wiley Periodicals, Inc.
Background
Since the standard gemcitabine and cisplatin (GC) chemotherapy for advanced bladder cancer yields limited therapeutic effect due to chemoresistance, it is a clinical challenge to enhance sensitivity to GC.
Methods
We performed high-throughput screening by using a library of known chemicals and repositionable drugs. A total of 2098 compounds were administered alone or with GC to human bladder cancer cells, and chemicals that enhanced GC effects were screened.
Results
Disulfiram (DSF), an anti-alcoholism drug, was identified as a candidate showing synergistic effects with cisplatin but not with gemcitabine in multiple cell lines. Co-administration of DSF with GC affected cellular localisation of a cisplatin efflux transporter ATP7A, increased DNA鈥損latinum adducts and promoted apoptosis. Micellar DSF nanoparticles (DSF-NP) that stabilised DSF in vivo, enhanced the inhibitory effect of cisplatin in patient-derived and cell-based xenograft models without severe adverse effects. A drug susceptibility evaluation system by using cancer tissue-originated spheroid culture showed promise in identifying cases who would benefit from DSF with cisplatin.
Conclusions
The present study highlighted the advantage of drug repurposing to enhance the efficacy of anticancer chemotherapy. Repurposing of DSF to a chemotherapy sensitiser may provide additional efficacy with less expense by using an available drug with a well-characterised safety profile.
Three strains of Mn-oxidizing fungi were isolated from manganese-rich aquatic environments: sediment in a stream (Komanoyu) in Mori-machi and inflow to an artificial wetland in Kaminokuni-cho, Hokkaido, Japan. The characteristics of each strain were then established. Genetic analysis based on the ribosomal RNA (rRNA) gene was performed to clarify their classification. The sequences of the 18S rRNA and internal transcribed spacer (ITS1)-5.8S rRNA-ITS2 genes showed that all three strains are Ascomycetes. Based on its morphology, it seems probable that the KY-1 strain from Mori-machi belongs to the genus Phoma or Ampelomyces. The phylogenetic analysis indicates that this strain belongs to Phoma rather than Ampelomyces. Morphological identification of WL-1 and WL-2 strains from Kaminokuni-cho was impossible because of the lack of a sexual stage and specific organs. Phylogenetic analysis of the sequence in the ITS1-5.8S rRNA-ITS2 gene suggests that the WL-1 strain corresponds to Paraconyothyrium sporulosum and that WL-2 also belongs to the genus Paraconiothyrium. Because the ability to oxidize Mn has not been evaluated for most species of Phoma or Paraconiothyrium (Coniothyrium), further study is needed to confirm the status of these three strains.
The effects of abiotic and biotic factors on the population dynamics of roti fers were investigated over two years in mesotrophic Lakes Ohnuma and Konuma (Hokkaido, Japan). Four rotifer species, Po lyarthra vulgaris, Trichocerca rousseleti, Keratella cochlearis and Filinia longiseta, dominated rotifer assemblages of both lakes. Their population densities changed seasonally with species-specific trajectories, but these dynamics were not related to seasonal variations in water temperature and dissolved oxygen content. Analysis of the population dynamics revealed that the instantaneous death rate affected the rate of the density change more strongly than the instantaneous birth rate in all dominant rotifer species. The estimated daily ration of predatory rotifers and copepods was higher than the estimated fi nite death rate of the rotifers in most cases. Effects of food limitation and competition with herbivorous crustaceans seemed to be less important compared to that of the invertebrates preda tion. These results indicate that in Lakes Ohnuma and Konuma the population dynam ics of rotifers were mainly determined by invertebrate predators through top-down control.
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