Characterization of Aquimarina hainanensis isolated from diseased mud crab Scylla serrata larvae in a hatchery     

Yuki Midorikawa  Tomohito Shimizu  Tetsuya Sanda  Katsuyuki Hamasaki  Shigeki Dan  Mohammad Tamrin Bin Mohamad Lal  Goshi Kato  Motohiko Sano 《Journal of fish diseases》2020,43(5):541-549

Mass mortality due to necrosis signs occurred in hatchery-reared zoea stage larvae of the mud crab Scylla serrata in Okinawa, Japan, and a causative bacterium was isolated. In this study, we identified and characterized the bacterium by genome analysis, biochemical properties and pathogenicity. The bacterium was a Gram-negative, non-motile, long rod, forming yellow colonies on a marine agar plate. It grew at 20–33°C (not at 37°C) and degraded chitin and gelatin. Phylogenetic analysis of the 16S rRNA gene sequence identified the bacterium as Aquimarina hainanensis. Genome sequence data obtained from Illumina MiSeq generated 29 contigs with 3.56 Mbp in total length and a G + C content of 32.5%. The predicted 16 chitinase genes, as putative virulence factors, had certain homologies with those of genus Aquimarina. Experimental infection with the bacterium conducted on larvae of four crustacean species, brine shrimp Artemia franciscana, freshwater shrimp Caridina multidentata, swimming crab Portunus trituberculatus and mud crab S. serrata, revealed that this bacterium was highly virulent to these species. The present study suggests that the bacterium caused mass mortality in mud crab seed production was A. hainanensis and can be widely pathogenic to crustaceans.  相似文献   

α-Melanocyte-stimulating hormone directly increases the plasma calcitonin level and involves calcium metabolism in goldfish     

Ikari  Takahiro  Kobayashi  Yuki  Kitani  Yoichiro  Sekiguchi  Toshio  Endo  Masato  Kambegawa  Akira  Asahina  Kiyoshi  Hattori  Atsuhiko  Tabuchi  Yoshiaki  Amornsakun  Thumronk  Mizusawa  Kanta  Takahashi  Akiyoshi  Suzuki  Nobuo 《International Aquatic Research》2018,10(3):283-292

International Aquatic Research - The effects of α-melanocyte-stimulating hormone (α-MSH) on calcium metabolism were examined with goldfish. The scales on the left side of goldfish bodies...  相似文献   

Correction to: A new and simple method for measuring in situ field-saturated hydraulic conductivity using a falling-head single cylinder     

Noborio  Kosuke  Ito  Yuki  He  Hailong  Li  Min  Kojima  Yuki  Hara  Hirofumi  Mizoguchi  Masaru 《Paddy and Water Environment》2018,16(1):81-87

Paddy and Water Environment - Hydraulic properties of soil play important roles in water and temperature regimes. Measuring hydraulic properties has been studied for decades in the laboratory and...  相似文献   

Biological control of potato scab and antibiosis by antagonistic Streptomyces sp. WoRs-501     

Yuki O. Kobayashi  Akira Kobayashi  Masayuki Maeda  Nobutaka Someya  Shigehito Takenaka 《Journal of General Plant Pathology》2015,81(6):439-448

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Protection induced by volatile limonene against anthracnose disease in Arabidopsis thaliana     

Kayoko Fujioka  Haruko Gotoh  Taku Noumi  Ami Yoshida  Yoshiteru Noutoshi  Yoshishige Inagaki  Mikihiro Yamamoto  Yuki Ichinose  Tomonori Shiraishi  Kazuhiro Toyoda 《Journal of General Plant Pathology》2015,81(6):415-419

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MytiLec,a Mussel R-Type Lectin,Interacts with Surface Glycan Gb3 on Burkitt’s Lymphoma Cells to Trigger Apoptosis through Multiple Pathways     

Imtiaj Hasan  Shigeki Sugawara  Yuki Fujii  Yasuhiro Koide  Daiki Terada  Naoya Iimura  Toshiyuki Fujiwara  Keisuke G. Takahashi  Nobuhiko Kojima  Sultana Rajia  Sarkar M. A. Kawsar  Robert A. Kanaly  Hideho Uchiyama  Masahiro Hosono  Yukiko Ogawa  Hideaki Fujita  Jiharu Hamako  Taei Matsui  Yasuhiro Ozeki 《Marine drugs》2015,13(12):7377-7389

MytiLec; a novel lectin isolated from the Mediterranean mussel (Mytilus galloprovincialis); shows strong binding affinity to globotriose (Gb3: Galα1-4Galβ1-4Glc). MytiLec revealed β-trefoil folding as also found in the ricin B-subunit type (R-type) lectin family, although the amino acid sequences were quite different. Classification of R-type lectin family members therefore needs to be based on conformation as well as on primary structure. MytiLec specifically killed Burkitt''s lymphoma Ramos cells, which express Gb3. Fluorescein-labeling assay revealed that MytiLec was incorporated inside the cells. MytiLec treatment of Ramos cells resulted in activation of both classical MAPK/ extracellular signal-regulated kinase and extracellular signal-regulated kinase (MEK-ERK) and stress-activated (p38 kinase and JNK) Mitogen-activated protein kinases (MAPK) pathways. In the cells, MytiLec treatment triggered expression of tumor necrosis factor (TNF)-α (a ligand of death receptor-dependent apoptosis) and activation of mitochondria-controlling caspase-9 (initiator caspase) and caspase-3 (activator caspase). Experiments using the specific MEK inhibitor U0126 showed that MytiLec-induced phosphorylation of the MEK-ERK pathway up-regulated expression of the cyclin-dependent kinase inhibitor p21, leading to cell cycle arrest and TNF-α production. Activation of caspase-3 by MytiLec appeared to be regulated by multiple different pathways. Our findings, taken together, indicate that the novel R-type lectin MytiLec initiates programmed cell death of Burkitt’s lymphoma cells through multiple pathways (MAPK cascade, death receptor signaling; caspase activation) based on interaction of the lectin with Gb3-containing glycosphingolipid-enriched microdomains on the cell surface.  相似文献   

Ability of heifers to discriminate between familiar herdmates and members of an unfamiliar group: preference test and operant conditioning test     

Yuki KOBA  Lene MUNKSGAARD  Hajime TANIDA  Lene PEDERSEN 《Animal Science Journal》2009,80(1):98-103

Using a preference test and operant conditioning in a Y-maze, this experiment examined the ability of heifers to discriminate between their own familiar herdmates and member(s) of an unfamiliar group. Sixteen Danish Friesian heifers, eight older animals (360.6 ± 24.2 days of age) and eight younger ones (190.1 ± 14.1 days of age) were used. Each age group was further divided into two experimental groups. Members of each of these groups were housed together in small pens before the experiments began. In experiment 1, each of the 16 animals was allowed to approach either a familiar or an unfamiliar individual in the Y-maze. The test was repeated 12 times, with a different unfamiliar subject for each test. In experiment 2, eight heifers were individually tested in a conditioning experiment to examine whether they could learn to discriminate between a group of their three herdmates and a group of three unfamiliar heifers. Test animals were rewarded when they chose their own group. In experiment 1, heifers did not show a preference between familiar and unfamiliar individuals. Interestingly the younger stimulus heifers but not the test animals showed an ability to discriminate between unfamiliar animals by vocalizing. In experiment 2, four of the eight test animals achieved the criterion for successful discrimination between the familiar and unfamiliar group ( P  < 0.003: binomial law). There was no age group difference in the ability to discriminate between familiar and unfamiliar animals. In conclusion, heifers did not show a preference toward familiar or unfamiliar individuals; but after conditioning, some heifers could learn to discriminate between familiar and unfamiliar groups.  相似文献   

Species diversity of the marine diatom genus Skeletonema in Japanese brackish water areas     

Machiko Yamada  Mayuko Otsubo  Yuki Tsutsumi  Chiaki Mizota  Naoki Iida  Kazuma Okamura  Masashi Kodama  Akira Umehara 《Fisheries Science》2013,79(6):923-934

The genus Skeletonema includes phytoplankton species that are important primary producers in marine food chains. Brackish waters have been reported to be one of the important habitats of some species of Skeletonema. To elucidate the species diversity of Skeletonema in brackish waters, we investigated three Japanese brackish bodies of water: the coastal waters of Toyama Bay, a tidal area of the Chikugo River, and a constructed reservoir in Isahaya Bay. We used molecular analysis based on large subunit rDNA and fine morphological structure to identify species. Skeletonema costatum s.s. (sensu stricto) was isolated at salinities as low as 0.6, but Skeletonema dohrnii, Skeletonema subsalsum, and Skeletonema tropicum were not found at salinities below 11.0. S. costatum s.s. could survive transfer from a medium with a salinity of 15 to a salinity of 2, but S. dohrnii did not survive in the same experiment. Only S. costatum s.s. germinated from the sediment of a reservoir in which the salinity was 0.1–1.4; incubation conditions included temperatures of 10, 15, 20, 25, and 30 °C and salinities of 5 and 30. Skeletonema costatum s.s. was identified as the species most adaptable to low-level salinity variations throughout its lifecycle.  相似文献   

Allelopathic potential of itchgrass (Rottboellia exaltata L. f.) powder incorporated into soil     

KATSUICHIRO KOBAYASHI  DAIGO ITAYA  PHARNUWAT MAHATAMNUCHOKE  TOSAPON PORNPROM 《Weed Biology and Management》2008,8(1):64-68

Itchgrass ( Rottboellia exaltata L. f.) is a widespread weed in northern Thailand. The farmers in this area have been using itchgrass as a mulching material in order to control other weeds in vegetable fields. Laboratory experiments were undertaken to investigate the phytotoxic activity of itchgrass powder incorporated into soil in order to evaluate the allelopathic activity in the field. The phytotoxic activity on the growth of radish seedlings ( Raphanus sativa L. var. radicula ), used as a test plant, was more pronounced in the root than in the shoot growth. The phytotoxic activity was found to be similar for the soils incorporated with the shoot or the root powder of itchgrass. The growth of the radish seedlings grown in sea sand and watered with soil water obtained from the soil previously incorporated with itchgrass powder showed a similar inhibition to those planted in the treated soil. The phytotoxic activity on the growth of the radish seedlings in the soil incorporated with the powder decreased over time. It is suggested that itchgrass releases phytotoxic compound(s) into soil water and the concentration of the active compound(s) in the soil water decreases over time.  相似文献   

Annual changes in macrobenthos abundance in Funka Bay,Japan     

Yuta?InagakiEmail author  Tetsuya?Takatsu  Yuki?Ashida  Toyomi?Takahashi 《Fisheries Science》2012,78(3):647-659

The temporal variation in macrobenthos abundance was studied in Funka Bay in the periods 2001–2004 and 2007–2010. Dissolved oxygen just above the sea floor of the basin was lower and ignition loss at the level of the sea floor was higher in 2007–2010 than in 2001–2004. Macrobenthic species were categorized into three groups: long-lived species, sedental polychaeta Notomastus latericeus, and short-lived species. Ignition loss was the most influential factor affecting macrobenthos abundance as this variable restricts the recruitment of macrobenthos. The abundance of both long-lived species and N. latericeus was lower between 2007 and 2010 than between 2001 and 2004. Supplementation of oxygen from outside the bay by the Tsugaru Warm Current may be an important factor impacting the increase in the abundance of long-lived species. The abundance of N. latericeus barely increased between 2007 and 2010, possibly because dissolved organic matter, which is their food item, may have become limited due to a narrow chink between sediments with eutrophication. The abundances of short-lived species did not differ between the periods 2001–2004 and 2007–2010 due to the organisms having a low tolerance to hypoxia. The current conditions in Funka Bay are on the verge of turning the bay into an azoic zone.  相似文献