Published Papers - KOGURE Kazuhiro

Bacterial response to glucose addition: growth and community structure in seawater microcosms from North Pacific Ocean.

Haider MN, Iqbal MM, Nishimura M, Ikemoto E, Ijichi M, Kogure K

Scientific reports ( Scientific Reports )  13 ( 1 ) 341   2023.01 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI
• Search related information
  PubMed

Diversity and Composition of Microbial Communities in an Eelgrass (<i>Zostera marina</i>) Bed in Tokyo Bay, Japan

Md Mehedi Iqbal, Masahiko Nishimura, Md. Nurul Haider, Masayoshi Sano, Minoru Ijichi, Kazuhiro Kogure, Susumu Yoshizawa

Microbes and Environments ( Japanese Society of Microbial Ecology )  36 ( 4 ) n/a - n/a   2021 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI

Bacterial enhancement of gel particle coagulation in seawater

Yosuke Yamada, Hideki Fukuda, Yuya Tada, Kazuhiro Kogure, Toshi Nagata

Aquatic Microbial Ecology ( Inter-Research )  77 ( 1 ) 11 - 22   2016 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Gel-like particles are ubiquitous in marine environments, affecting global carbon cycles, but the mechanisms controlling gel particle coagulation in seawater are not entirely clear. We investigated whether marine bacteria enhance the coagulation of gel particles. Gel particles composed of polysaccharides with an equivalent spherical diameter (ESD) of 0.01 cm were suspended in seawater contained in rotating tubes to examine time course changes in particle ESD and abundance. Marine bacterial assemblages strongly enhanced the coagulation of gel particles into large aggregates (ESD, 0.1 to 1 cm) over a period of 24 to 96 h. Catalyzed reporter deposition fluorescence in situ hybridization revealed that one group of bacteria that grew rapidly was affiliated with the genus Pseudoalteromonas. Experiments using Pseudoalteromonas spp. isolates indicated that 6 of 11 isolates enhanced gel particle coagulation. This enhancement differed greatly by species. High settling velocities, up to 270 m d-1, were determined for the large aggregates. Our results demonstrate that bacteria can substantially enhance gel particle coagulation and the formation of fast-settling large aggregates in seawater.

• Access this article

  DOI

Aurantivirga profunda gen. nov., sp nov., isolated from deep-seawater, a novel member of the family Flavobacteriaceae

Jaeho Song, Ahyoung Choi, Mihye Im, Yochan Joung, Susumu Yoshizawa, Jang-Cheon Cho, Kazuhiro Kogure

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ( SOC GENERAL MICROBIOLOGY )  65   4850 - 4856   2015.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

A Gram-stain-negative, aerobic, proteorhodopsin-containing, orange, rod-shaped bacterium, designated SAORIC-234(T), was isolated from deep seawater in the Pacific Ocean. 16S rRNA gene sequence analysis revealed that the strain could be affiliated with the family Flavobacteriaceae of the phylum Bacteroidetes and shared less than 94.6 % similarity with other species of the family with validly published names. The phenotypic characteristics of this novel isolate, such as growth properties and enzyme activities, could be differentiated from those of other species. The strain was non-motile, oxidase-positive and catalase-negative. The G+C content of the genomic DNA was determined to be 34.8 mol% and menaquinone-6 (MK-6) was the predominant isoprenoid quinone. The predominant fatty acids were iso-C-15 iso-C-15 G, iso-C-16 (:) (0) 3-OH, iso-C-17 (:) (0) 3-OH and iso-C-15 (:) (0) 3-OH. The major polar lipids comprised phosphatidylethanolamine, three unknown aminolipids and three unknown lipids. On the basis of the taxonomic data collected in this study, it was concluded that strain SAORIC-234(T) represents a novel genus and species in the family Flavobacteriaceae, for which the name Aurantivirga profunda gen. nov., sp. nov. is proposed. The type strain of the type species, Aurantivirga profunda sp. nov., is SAORIC-234(T) (=NBRC 110606(T)=KACC 18400(T)).

• Access this article

  DOI
• Search related information
  PubMed

Aureicoccus marinus gen. nov., sp nov., a member of the family Flavobacteriaceae, isolated from seawater

Sanghwa Park, Susumu Yoshizawa, Yuki Muramatsu, Yasuyoshi Nakagawa, Akira Yokota, Kazuhiro Kogure

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ( SOC GENERAL MICROBIOLOGY )  63   1885 - 1890   2013.05 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

A coccoid and amorphous-shaped, non-gliding, proteorhodopsin-containing, yellow bacterium, designated strain SG-18(T), was isolated from seawater in the western North Pacific Ocean near Japan. The strain was Gram-stain-negative, obligately aerobic, heterotrophic and oxidase-positive. It hydrolysed aesculin but not DNA, urea, gelatin or agar. Growth occurred in the presence of 1 5 % NaCl, with optimum growth at 2% NaCl. The strain grew at 15-37 degrees C with an optimum temperature of 25-30 degrees C. The DNA G+C content of the genomic DNA of strain SG-18(T) was 47.0 mol% (HPLC). The predominant isoprenoid quinone was MK-6, and major cellular fatty acids were iso-C-15:1 G, iso-C-15:0, iso-C-15:0 3-OH. Phylogenetic trees generated by using 16S rRNA gene sequences revealed that strain SG-18(T) belonged to the family Flavobacteriaceae and showed 92.7% sequence similarity to the most closely related species, Croceitalea eckloniae DOKDO 025(T). On the basis of phenotypic and phylogenetic features, strain SG-18(T) is classified as representing a novel species of a new genus within the family Flavobacteriaceae, for which the name Aureicoccus marinus gen. nov., sp. nov. is proposed. The type strain of the type species is SG-18(T) (=NBRC 108814(T)=KCTC 23967(T)).

• Access this article

  DOI
• Search related information
  PubMed

A light-driven sodium ion pump in marine bacteria

Keiichi Inoue, Hikaru Ono, Rei Abe-Yoshizumi, Susumu Yoshizawa, Hiroyasu Ito, Kazuhiro Kogure, Hideki Kandori

Nature Communications   4   1678   2013 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Light-driven proton-pumping rhodopsins are widely distributed in many microorganisms. They convert sunlight energy into proton gradients that serve as energy source of the cell. Here we report a new functional class of a microbial rhodopsin, a light-driven sodium ion pump. We discover that the marine flavobacterium Krokinobacter eikastus possesses two rhodopsins, the first, KR1, being a prototypical proton pump, while the second, KR2, pumps sodium ions outward. Rhodopsin KR2 can also pump lithium ions, but converts to a proton pump when presented with potassium chloride or salts of larger cations. These data indicate that KR2 is a compatible sodium ion-proton pump, and spectroscopic analysis showed it binds sodium ions in its extracellular domain. These findings suggest that light-driven sodium pumps may be as important in situ as their proton-pumping counterparts. © 2013 Macmillan Publishers Limited. All rights reserved.

• Access this article

  DOI
• Search related information
  PubMed

Anomalous pH Effect of Blue Proteorhodopsin

Keisuke Yamada, Akira Kawanabe, Susumu Yoshizawa, Kentaro Inoue, Kazuhiro Kogure, Hideki Kandori

JOURNAL OF PHYSICAL CHEMISTRY LETTERS ( AMER CHEMICAL SOC )  3 ( 7 ) 800 - 804   2012.04 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Proteorhodopsin (PR) is a light-driven proton pump found in marine bacteria, and thousands of PRs are classified into blue-absorbing PR (B-PR; lambda(max) approximate to 490 nm) and green-absorbing PR (G-PR; lambda(max) approximate to 525 nm). In this report, we present conversion of B-PR into G-PR using anomalous pH effect B-PR in LC1-200, marine gamma-proteobacteria, absorbs 497 and 513 nm maximally at pH 7 and 4, respectively, whose pH titration was reversible (pK(a) = 4.8). When pH was lowered from 4, the lambda(max) was further red-shifted (528 nm at pH 2). This is unusual because blue shift occurs by chloride binding in the case of bacteriorhodopsin. Surprisingly, when pH was increased from 2 to 7, the lambda(max) of this B-PR was further red-shifted to 540 nm, indicating that green-absorbing PR (PR540) is created only by changing pH. The present study reports the conformational flexibility of microbial rhodopsins, leading to the switch of absorbing color by a simple pH change.

• Access this article

  DOI

Aureitalea marina gen. nov., sp nov., a member of the family Flavobacteriaceae, isolated from seawater

Sanghwa Park, Susumu Yoshizawa, Kentaro Inomata, Kazuhiro Kogure, Akira Yokota

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ( SOC GENERAL MICROBIOLOGY )  62   912 - 916   2012.04 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

An irregular rod-shaped, non-gliding, yellow-pigmented bacterium was isolated from seawater from the western North Pacific Ocean near Japan. The strain, designated S1-66(T), was Gram-negative, obligately aerobic, heterotrophic and oxidase-positive. Growth occurred in the presence of 1-4 % NaCl, with optimum growth at 2% NaCl. The strain grew at 15-30 degrees C, with optimum growth at 20-25 degrees C. The G +C content of genomic DNA was 48.1 mol% (HPLC). The predominant isoprenoid quinone was MK-6 and the major cellular fatty acids were iso-C-15:0 (26.4%), iso-C-15:1 (20.3 %) and iso-C-17:0 3-OH (14.2%). Phylogenetic trees generated by using 16S rRNA gene sequences revealed that strain S1-66(T) belongs to the family Flavobacteriaceae and showed 94.2% sequence similarity to the most closely related type strain, Ulvibacter antarcticus IMCC3101(T). On the basis of phenotypic and phylogenetic features, S1-66(T) is classified in a novel genus and species within the family Flavobacteriaceae, for which the name Aureitalea marina gen. nov., sp. nov. is proposed. The type strain of Aureitalea marina is S1-66(T) (=NBRC 107741(T) =KCTC 23434(T)).

• Access this article

  DOI
• Search related information
  PubMed

Analysis of Styrene Oligomer Contaminants Generated from Marine Debris Polystyrene on the Coast of Okinawa

Katsuhiko Saido, Keiji Amamiya, Hideto Sato, Akifumi Okabe, Naoto Ogawa, Yasushi Kamaya, Kazuhiro Kogure, Masahiko Nishimura, Kouji Okukawa, Takashi Kusui

Bunseki Kagaku   61 ( 7 ) 629 - 636   2012 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Marine debris plastics (50000 to 150000 tons) have washed up every year to Japan. Seventy percent of this stranded debris is polystyrene (PS). Drift and stranded PS is presumed to generate styrene oligomer (SO) in the marine environment. In this study, field work was carried out to clarify the pollution of the coastal area by such chemicals as SO derived from PS. Therefore, sea water and sand were collected at the investigation sites, while visual observations were made in Okinawa island and Yaeyama islands (Iriomoteshima Island and Ishigakishima Island). These are representative islands to which many drift plastics arising from Asian countries are washed up. From a SIM-GC/MS analysis of picked-up sea water and sand, SO (styrene monomer phenylethylene, SM styrene dimer, 2,4-diphenyl-1-butene, SD styrene trimer, 2,4,6-triphenyl-1-hexene, ST) were detected at every sampling site. Among SO, ST was found to be contained most abundantly in the sea sand 4400 ng/g of ST was detected as the maximum level. The SO composition determined by an analysis of sea sand and water tended to be almost similar to the SO composition of the purified PS thermal decomposition of the markets PS. © 2012, The Japan Society for Analytical Chemistry. All rights reserved.

• Access this article

  DOI

Aliivibrio sifiae sp nov., luminous marine bacteria isolated from seawater

Susumu Yoshizawa, Hajime Karatani, Minoru Wada, Akira Yokota, Kazuhiro Kogure

JOURNAL OF GENERAL AND APPLIED MICROBIOLOGY ( MICROBIOL RES FOUNDATION )  56 ( 6 ) 509 - 518   2010.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

A Global Census of Marine Microbes

Linda Amaral-Zettler, Luis Felipe Artigas, John Baross, Loka Bharathi P.A., Antje Boetius, Dorairajasingam Chandramohan, Gerhard Herndl, Kazuhiro Kogure, Phillip Neal, Carlos Pedrós-Alió, Alban Ramette, Stefan Schouten, Lucas Stal, Anne Thessen, Jan De Leeuw, Mitchell Sogin

Life in the World's Oceans: Diversity, Distribution, and Abundance ( Wiley-Blackwell )    221 - 245   2010.11 [ Peer Review Accepted ]

Type of publication: Research paper (other science council materials etc.)

• Access this article

  DOI

Broad-host range gene transporter particles produced by Aliivibrio fischeri

Hiroshi Xavier Chiura, Nami Uchiyama, Kazuhiro Kogure

Microbes and Environments   24 ( 4 ) 322 - 329   2009.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Aliivibrio fischeri NCIMB1281T (basonym, Vibrio fischeri) spontaneously started broad-host range vector particle (AfVP) production by budding from the logarithmic phase, and stabilised at around 7.0×1010-7.4×1011 particles mL-1 without any accompanying change in the host population. AfVPs had a spherical shape and varied in diameter from 18.1 to 159.2 nm [median±SD, 58.4±11.9 nm, n=528], with 95.1% between 30.2 and 84.6 nm in diameter exhibiting a normal distribution. Their buoyant density and DNA content ranged from 1.3607 to 1.3980 g cm-3, and 17.3 to 95.3 kbp, respectively. Regardless of UV treatment, AfVPs enhanced the efficiency of plating 116-136% at a multiplicity of infection of ca. 140 in Escherichia coli AB1157. Generalised transduction was observed with a frequency of between 10-4 and 10-6 cells per AfVP without UV treatment. Upon infection, the particle membrane remained outside the recipient cell, and a string-like structure coated with a fibrous proteinaceous-like material was present. The growth of the E. coli transductant (AfV-E-trans) reached a maximum of ca. 415% that of the parental E. coli recipient. AfV-Etrans acquired the ability to produce budding particles.

• Access this article

  DOI

Analysis of Nanoplankton Community Structure Using Flow Sorting and Molecular Techniques

Noriaki Yoshida, Masahiko Nishimura, Katsuyuki Inoue, Susumu Yoshizawa, Eriko Kamiya, Akito Taniguchi, Koji Hamasaki, Kazuhiro Kogure

MICROBES AND ENVIRONMENTS ( JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE )  24 ( 4 ) 297 - 304   2009 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

We developed a method for the separate and simultaneous analysis of the community structure of heterotrophic nanopkankton (HNP) and autotrophic nanoplankton (ANP). This method consists of three steps. First, nanoplankton cells were concentrated using a cross-flow filtration system because cell densities in natural seawater are usually too low for genetic studies. Second, HNP and ANP were separated by flow cytometric sorting ("flow sorting") on the basis of the presence or absence of chlorophyll. Finally, the community structure was analyzed using denaturing gradient gel electrophoresis targeting 18S rRNA gene. The newly developed method was applied to the coastal surface water of Aburatsubo Inlet, Japan, in July 2008. The separation of nanoplankton into HNP and ANP was validated by phylogenetic analysis, and the trophic mode of uncultured nanoplankton was confirmed (e.g. Marine Alveolata group II [MALV II] and Marine Stramenopile clade-2 [MAST-2]). This new method involving cell concentration, flow sorting and phylogenetic analysis is a potentially powerful tool for evaluating the population dynamics and ecology of marine protozoa.

• Access this article

  DOI
• Search related information
  PubMed

Actinomycetal community structures in seawater and freshwater examined by DGGE analysis of 16S rRNA gene fragments

Akihiro Yoshida, Yuna Seo, Shuhei Suzuki, Tomohiko Nishino, Takeshi Kobayashi, Naoko Hamada-Sato, Kazuhiro Kogure, Chiaki Imada

MARINE BIOTECHNOLOGY ( SPRINGER )  10 ( 5 ) 554 - 563   2008.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

The actinomycetal community structures in marine and freshwater environments (the Pacific Ocean, East China Sea, Tokyo Bay, and Arakawa River) were investigated by a culture-independent molecular method to clarify spatial and seasonal distributions. Deoxyribonucleic acid (DNA) was extracted from environmental water samples, and a community analysis was carried out on polymerase chain reaction-amplified 16S ribosomal DNA. The amplified DNA fragments were analyzed by denaturing gradient gel electrophoresis (DGGE) and nonmetric multidimensional scaling analysis, followed by sequencing analysis. The actinomycetal community structures were different at each station in the Pacific Ocean, the East China Sea, Tokyo Bay, and Arakawa River, and different populations predominated in each area. There were vertical variations in actinomycetal communities in the Pacific Ocean and East China Sea between the surface and 100-m depth, but communities were similar from 200- to 1,000-m depths. There were also distinct seasonal variations in communities in Tokyo Bay. Phylogenetic analysis of DNA fragments recovered from DGGE bands revealed that most of the predominant actinomycetal strains were uncultured and were quite different from well known culturable strains, such as the Streptomyces, Micromonospora, Microbispora, Salinispora, and Actinoplanes groups. These results suggest that the marine environment is an attractive target for discovering new actinomycetal populations producing bioactive compounds and that sampling depth and season are important considerations for isolating various populations effectively.

• Access this article

  DOI

Automatic counting of FISH-labeled microbes by an LED illuminated detecting apparatus

Masahiko Nishimura, Tomonori Shimakita, Takuhiro Matsuzaki, Yoshikazu Tashiro, Kazuhiro Kogure

FISHERIES SCIENCE ( SPRINGER TOKYO )  74 ( 2 ) 405 - 410   2008.04 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

The Bioplorer (BP) (Matsushita Ecology Systems Co. Ltd, Kasugai, Aichi-ken, Japan) is an apparatus that consists of a light-emitting diode and optical and image analysis systems. This instrument has been developed and used for the semi-automatic counting of total microbes, mainly in food, cosmetics and industrial products. In this study, the applicability of BP to the detection and enumeration of eukaryotic and prokaryotic cells, after the fluorescent in situ hybridization (FISH) procedure, was examined. The cells of a yeast (Candida albicans) and a bacterium (Escherichia coli) were specifically labeled using an oligonucleotide probe with fluorochrome and then counterstained with 4&apos;, 6-diamidino-2-phenylindole (DAPI). The numbers of cells after FISH treatment and DAPI staining agreed well, indicating that the BP optical device and image analysis system had enough sensitivity to detect and quantify eukaryotic and prokaryotic cells. Because of its simplicity and reliability, BP can be a new tool for quantification of specifically labeled target microorganisms, both in industrial products and natural samples.

• Access this article

  DOI

Bacterial community structure in the Sulu Sea and adjacent areas

Akihiro Yoshida, Masahiko Nishimura, Kazuhiro Kogure

DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY ( PERGAMON-ELSEVIER SCIENCE LTD )  54 ( 1-2 ) 103 - 113   2007 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

The deep waters of the Sulu Sea are characterized by relatively high and constant water temperatures and low oxygen concentrations. To examine the effect of these characteristics on the bacterial community structure, the culture-independent molecular method was applied to samples from the Sulu Sea and the adjacent areas. DNA was extracted from environmental samples, and the analysis was carried out on PCR-amplitied 16S rDNA; fragments were analyzed by denaturing gradient gel electrophoresis (DGGE) and nonmetric multidimensional scaling analysis. Stations in the Sulu Sea and the adjacent areas showed much more prominent vertical stratification of bacterial community structures than horizontal variation. As predominant sequences, cyanobacteria and alpha-proteobacteria at 10 m depth, delta-proteobacteria at 100 in depth, and green nonsulfur bacteria below 1000 m depth were detected in all sampling areas. High temperatures and low oxygen concentrations are thought to be minor factors in controlling community structure; the quantity and quality of organic materials supplied by the sinking particles, and hydrostatic pressure are believed to be important. (c) 2006 Elsevier Ltd. All rights reserved.

• Access this article

  DOI

Different ingestion patterns of C-13-labeled bacteria and algae by deep-sea benthic foraminifera

Hidetaka Nomaki, Petra Heinz, Takeshi Nakatsuka, Motohiro Shimanaga, Naohiko Ohkouchi, Nanako O. Ogawa, Kazuhiro Kogure, Eiko Ikemoto, Hiroshi Kitazato

MARINE ECOLOGY PROGRESS SERIES ( INTER-RESEARCH )  310   95 - 108   2006 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Benthic foraminiferal food sources were examined in the central part of Sagami Bay, Japan (water depth 1450 m) based on an in situ feeding experiment with C-13-labeled food materials. In this study, 3 different C-13-labeled food materials were used: the unicellular marine algae Dunaliella tertiolecta, the marine diatom Chaetoceros sociale, and the marine bacterium Vibrio alginolyticus. The first two are representatives of phytodetritus and the third of organic matter produced in the sediments. Each type of food material was injected into a series of in situ culture cores and incubated for up to 21 d. We observed that some benthic foraminiferal species selectively ingested C-13-labeled algae from the sedimentary organic matter. On the other hand, benthic foraminifera ingested C-13-labeled bacteria unselectively from sedimentary organic matter. Total benthic foraminifera assimilated 8.8 mg C m(-2) d(-1) of sedimentary organic matter without phytodetritus assimilation. Based on the assimilation rates estimated in this experiment, we recognized 3 types of feeding strategy among deep-sea benthic foraminifera in Sagami Bay. There are those that ingest (1) fresh phytodetritus selectively (phytophagous species: Uvigerina akitaensis, Bolivina spissa, Bolivina pacifica); (2) fresh phytodetritus selectively but sedimentary organic matter as well when phytodetritus is absent (seasonal-phytophagous species: Bulimina aculeata, Textularia kattegatensis, Globobulimina affinis); and (3) sedimentary organic matter at random (deposit feeders: Cyclammind cancellata, Chilostomella ovoidea). These different types of carbon utilization should be considered not only for understanding modern ecosystems on the deep-sea floor but also for paleoceanographic reconstructions using the abundance and distribution, or isotopic composition, of benthic foraminifera.

• Access this article

  DOI

Application of AFM to marine micro-organisms

KOGURE Kazuhiro

kenbikyo ( The Japanese Society of Microscopy )  38 ( 2 ) 83 - 85   2003.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI

An Improved Method of Tissue Culture Bioassay for Tetrodotoxin

Koji Hamasaki, Kazuhiro Kogure, Kouichi Ohwada

Fisheries Science ( Blackwell Publishing )  62 ( 5 ) 825 - 829   1996 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

A tissue culture bioassay, using the mouse neuroblastoma cell line (Neuro2A), was improved to provide a simple and sensitive bioassay for TTX. The tetrazolium salt, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) was applied to replace the time-consuming and incomplete procedure of the original method with automatic measurement, using a microplate reader. TTX was used as a standard and an S-shaped dose-response curve was obtained. In addition to the relative ease of use and objectivity, sensitivity was found to be several times higher than the original (half-maximal inhibition was 12.9 nM TTX). The applicability of this method for detection of TTX produced by bacteria was investigated. Extracts prepared from E. coli cells were amended with a known concentration of TTX and used to determine the effect of this addition to the sample. Although the highly concentrated extract showed cytotoxicity, the effect was reduced when the extract was diluted or purified appropriately. The tetrazolium-based tissue culture bioassay described here may be useful for monitoring or screening for sodium channel blockers (SCB).

• Access this article

  DOI

COUPLING BETWEEN THE RESPIRATORY-CHAIN AND THE LUMINESCENT SYSTEM OF VIBRIO-HARVEYI

M WADA, K KOGURE, K OHWADA, U SIMIDU

JOURNAL OF GENERAL MICROBIOLOGY ( SOC GENERAL MICROBIOLOGY )  138   1607 - 1611   1992.08 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Effects of monovalent cations on luminescence and respiratory activity were studied in the marine luminous bacterium Vibrio harveyi. Maximum oxygen uptake was observed in the presence of Na+ over the pH range tested (6.5-8.5). At alkaline pH, effects of monovalent cation on luminescence were similar to those on the oxygen uptake. Although KCN addition caused a marked increase in luminescence, the enhanced luminescence with Na+ was still greater than that with Li+. However, at acidic pH, K+ increases luminescence more than Na+ does. These results indicate that there is not only a competitive but also a cooperative relationship between luminescence and respiration. The respiratory NADH oxidase in the membrane fraction of V. harveyi showed some distinctive characters which are unique to the respiratory-dependent primary Na+ pump, suggesting the possibility of coupling between the Na+ pump and the luciferase system. This was also supported by the results from CCCP-resistant growth and luminescence at alkaline pH. The coupling mechanisms between luminescence and respiration in V. harveyi are discussed.