Migration of erythroblastic islands toward the sinusoid as erythroid maturation proceeds in rat bone marrow

It has been hitherto considered that mature erythroblasts migrate toward the sinusoid along the cytoplasmic processes of macrophages of erythroblastic islands in bone marrow. Our previous report, however, has demonstrated the morphological features of a mature erythroblastic island passing through the sinusoidal endothelium. In this study, the possibility of migration of erythroblastic islands toward the sinusoid was examined in rat bone marrow by light microscopical histoplanimetry. As a result, the more mature erythroblasts were not regularly arranged in the peripheral direction of the erythroblastic islands. Immature erythroblasts were populated more in the erythroblastic islands away from the sinusoid than in those islands neighboring the sinusoid, whereas mature erythroblasts were more in erythroblastic islands neighboring the sinusoid. These findings suggest that the formation of erythroblastic islands occurs in a region away from the sinusoid, and that erythroblastic islands migrate towards the sinusoids as erythroid maturation proceeds.     

New canker diseases of Abies veitchii and Acer crataegifolium caused by Neonectria castaneicola

New perennial canker diseases of Abies veitchii and Acer crataegifolium are described. Pathogenicity of the causal fungus was confirmed on stems of young Abies and Acer trees using two monoascospore isolates from the perithecia from the two tree species. The causal fungus, producing Nectria-state-teleomorph and Cylindrocarpon-anamorph, was identified as Nectria castaneicola. It was then transferred to the genus Neonectria, as N. castaneicola (W. Yamam. et Oyasu) Tak. Kobay. et Hirooka, comb. nov. followed by the recent concept of Nectriaceae.     

Tumor promoting effect of phenolphthalein on development of lung tumors induced by N-ethyl-N-nitrosourea in transgenic mice carrying human prototype c-Ha-ras gene

In order to examine tumor modifying effects of phenolphthalein (PhP), female transgenic mice carrying human prototype c-Ha-ras gene (rasH2 mice) were given a single intraperitoneal injection of 60 mg/kg body weight of N-ethyl-N-nitrosourea (ENU), followed by the diet containing 12,000 ppm PhP for 26-week. Histopathologically, alveolar hyperplasias, adenomas and adenocarcinomas were observed in the ENU + PhP group, but only hyperplasias and adenomas were observed in the ENU alone group. The incidence and multiplicity of adenocarcinomas in the ENU + PhP group was significantly increased as compared to that in the ENU alone group. The combined multiplicity of adenomas and adenocarcinomas in this group was also significantly higher than that of the ENU alone group. In addition, the ratio of area of adenomas in the ENU + PhP group was significantly higher than that in the ENU alone group. The result of our study suggests that PhP has a clear tumor promoting effect in the lung of rasH2 mice.     

Anti-influenza A virus activities of mannan-binding lectins and bovine conglutinin

Mannan-binding lectin (MBL) and bovine conglutinin (BKg) belong to the collectin family, which is involved in first-line host defense against various infectious agents. We have previously reported that human MBL inhibited type A influenza viral hemagglutination, infection and spreading to adjacent cells without complement activation. In this study, we investigated the direct antiviral activities of bovine MBL, rabbit MBL and BKg. All collectins used in this study inhibited viral infectivity and hemagglutination at concentrations of 0.02-0.3 microg/ml. They also demonstrated inhibitory activity against viral spreading. Like human MBL, bovine MBL and BKg showed antiviral activities at their physiological concentrations. These results suggest that mammalian MBLs and BKg may inhibit the spread of influenza A virus through the bloodstream.     

Effect of long-term exposure to sulfides on taurine transporter gene expression in the gill of the deep-sea mussel Bathymodiolus platifrons,which harbors a methanotrophic symbiont

Seawater around deep-sea hydrothermal vents and cold seeps contain high levels of hydrogen sulfide, which is toxic to most animals. Invertebrates inhabiting these environments have been reported to accumulate high levels of thiotaurine, a sulfur-containing amino acid. Thiotaurine is likely to play an important role in sulfide detoxification, but its functions in the detoxification process are still unknown. We cloned methane-seep mussel Bathymodiolus platifrons cDNA encoding the taurine transporter (TAUT), which transports thiotaurine and its precursors across the cell membrane. Phylogenetic analyses revealed that the predicted peptide formed a clade with the TAUTs of shallow-water mussel Mytilus galloprovincialis and the hydrothermal vent mussel Bathymodiolus septemdierum that harbors thioautotrophic bacteria. We then reared B. platifrons in the presence or absence of Na₂S and quantified TAUT mRNA using a real-time PCR system. The amount of TAUT mRNA in the gills of B. platifrons increased with rearing in the presence of Na₂S for 69 days, but no change was observed in the absence of sulfide. These results suggest that TAUT plays an important role in sulfide detoxification, even in species that do not harbor thioautotrophic bacteria. The TAUT mRNA level was variable in the mantle and low in the foot throughout the entire rearing period, regardless of the presence/absence of sulfide, suggesting that TAUT gene expression is regulated differentially in each tissue.     

Comparison between surface-reading and cross-section methods using sagittal otolith for age determination of the marbled sole <Emphasis Type="Italic">Pseudopleuronectes yokohamae</Emphasis>

To find an appropriate method for age determination in the marbled sole Pseudopleuronectes yokohamae in Tokyo Bay, Japan, sagittal otoliths of 1,343 individuals were observed by surface-reading and cross-section methods and the results were compared. Opaque zones occurred once a year and were regarded as annuli in both methods. The surface-reading method sometimes provided a lower count of the number of annuli than the cross-section method, and the frequency of this discrepancy was highest in older fish (males above 5 years, females above 4 years). The oldest female fish was estimated to be age 10 years by the cross-section method but 8 years by the surface-reading method. The cross-section method could provide a more accurate estimate of age and is therefore likely to be indispensable to estimations of longevity. In contrast, the surface-reading method is superior in terms of cost and time efficiency but is likely to underestimate the ages of older fish. However, growth equations based on age estimated by the surface-reading method were sufficiently accurate if males ≥5 years and females ≥4 years were combined as specific, single age groups of 5+ and 4+, respectively.     

Preparation and crossing of mating-capable monokaryons via protoplasting of the dikaryotic mycelia of a mycorrhizal mushroom, <Emphasis Type="Italic">Lyophyllum shimeji</Emphasis>

In order to develop a novel method of obtaining monokaryons for a mycorrhizal fungus, Lyophyllum shimeji, monokaryotization of dikaryotic stock culture via protoplast formation and regeneration was performed using 12 dikaryotic stocks. From 6 dikaryotic stocks, a total of 120 monokaryons were isolated, and their mating compatibility was tested. Mating-compatible monokaryons were successfully derived from a dikaryotic stock (NBRC 100325), and monokaryons of only 1 mating type relative to the parental dikaryons were isolated from another 3 strains (MH01710, OK2L-1, and HY7L-1). We successfully prepared monokaryotic stocks via protoplast monokaryotization, a technique that can be used to identify biological species of L. shimeji. This technique could be used for breeding various mycorrhizal mushrooms, including Tricholoma matsutake, for which the preparation of monospore cultures is extremely difficult. Part of this study was presented at the 11th Annual Meeting of the Japanese Society of Mushroom Science and Biotechnology (Asahikawa), September 2007     

DedA protein relates to action-mechanism of halicyclamine A, a marine spongean macrocyclic alkaloid, as an anti-dormant mycobacterial substance

A macrocyclic alkaloid, halicyclamine A, was re-discovered from an Indonesian marine sponge of Haliclona sp. 05A08 as an anti-dormant mycobacterial substance. To clarify action-mechanism of halicyclamine A, halicyclamine A-resistant strains were screened from the transformants of Mycobacterium smegmatis with the genomic DNA library of M. bovis BCG, which were constructed in the multi-copy shuttle cosmid pYUB145. Sequencing analysis of the cosmids isolated from the halicyclamine A-resistant transformants revealed that the responsible gene was involved in the genome region between 2920.549 kb and 2933.210 kb. Further experiments using the transformants over-expressing individual gene contained in the responsible region were executed, and the transformant, which over-expressed BCG2664 gene assigned as dedA gene, was found to become halicyclamine A-resistant. This evidence strongly suggested that DedA protein correlates with the action-mechanism of halicyclamine A as an anti-dormant mycobacterial substance.     

Molecular cloning and expression of bottlenose dolphin CD34

In terrestrial mammals, the surface molecule CD34 is used as a marker to identify hematopoietic progenitor cells. To clarify whether CD34 expression can be used to confirm the undifferentiated state of hematopoietic-like cells isolated from the bone marrow of bottlenose dolphin, Tursiops truncates, we determined in this study the sequence of dolphin CD34 cDNA and analyzed its mRNA expression. Dolphin CD34 cDNA can be expressed as two forms, one that encodes a full-length version and a variant, truncated version of the gene. Both forms were detected in bone marrow mononuclear cells and in various tissues using RT-PCR. The truncated form was not detected in peripheral blood mononuclear cells, and neither form was detected in polymorphonuclear leukocytes. This is the first report on CD34 in marine mammals and our results suggest that dolphin CD34 may be a useful marker to identify hematopoietic progenitor cells.     

A functional dosage compensation complex required for male killing in Drosophila

Bacteria that selectively kill males ("male-killers") were first characterized more than 50 years ago in Drosophila and have proved to be common in insects. However, the mechanism by which sex specificity of virulence is achieved has remained unknown. We tested the ability of Spiroplasma poulsonii to kill Drosophila melanogaster males carrying mutations in genes that encode the dosage compensation complex. The bacterium failed to kill males lacking any of the five protein components of the complex.