Genki I. Matsumoto

Otsuma Women's University, Edo, Tōkyō, Japan

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Publications (56)120.22 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The frequency of extreme weather has been rising in recent years. A 3-year study of street trees was undertaken in Tokyo to determine whether: (i) street trees suffer from severe water stress in unusually hot summer; (ii) species respond differently to such climatic fluctuations; and (iii) street trees are also affected by nitrogen (N) deficiency, photoinhibition and aerosol pollution. During the study period (2010-12), midsummers of 2010 and 2012 were unusually hot (2.4-2.8 °C higher maximum temperature than the long-term mean) and dry (6-56% precipitation of the mean). In all species, street trees exhibited substantially decreased photosynthetic rate in the extremely hot summer in 2012 compared with the average summer in 2011. However, because of a more conservative stomatal regulation (stomatal closure at higher leaf water potential) in the hot summer, apparent symptoms of hydraulic failure were not observed in street trees even in 2012. Compared with Prunus × yedoensis and Zelkova serrata, Ginkgo biloba, a gymnosperm, was high in stomatal conductance and midday leaf water potential even under street conditions in the unusually hot summer, suggesting that the species had higher drought resistance than the other species and was less susceptible to urban street conditions. This lower susceptibility might be ascribed to the combination of higher soil-to-leaf hydraulic conductance and more conservative water use. Aside from meteorological conditions, N deficiency affected street trees significantly, whereas photoinhibition and aerosol pollution had little effect. The internal CO2 and δ(13)C suggested that both water and N limited the net photosynthetic rate of street trees simultaneously, but water was more limiting. From these results, we concluded that the potential risk of hydraulic failure caused by climatic extremes could be low in urban street trees in temperate regions. However, the size of the safety margin might be different between species.
    Tree Physiology 11/2014; 34(10). DOI:10.1093/treephys/tpu086 · 3.41 Impact Factor
  • 01/2013; 2013(23):189-197. DOI:10.9748/hcs.2013.189
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    ABSTRACT: We studied the geochemical features and compound-specific (CS)-δ13C of hydrocarbons and fatty acids in soil samples from the McMurdo Dry Valleys in the Antarctic to elucidate their source organisms and characteristics of their environments. Total organic carbon contents in soil samples were extremely low reflecting extremely harsh environments for organisms. Normal-alkanes ranging in carbon chain length from n-C14 to n-C38 with the predominance of odd-carbon numbers were found, together with n-alkenes (n-C23:1 to n-C27:1). Normal-alkanoic acids ranging in carbon chain length from n-C10 to n-C30 with the predominance of even-carbon numbers were detected in the samples, along with small amounts of branched (iso and anteiso) and n-alkenoic acids. CS-δ13C values of long-chain n-alkanes (n-C20 to n-C29) ranged from −30.4 to −26.6‰. CS-δ13C values of n-alkanoic acids with short-chain carbon numbers (n-C14 to n-C19) ranging from −27.7 to −21.7‰ were much higher than those of long-chain carbon numbers (n-C20 to n-C30, −32.5 to −25.3‰). The geochemical features and CS-δ13C values of long-chain n-alkanes and n-alkanoic acids revealed that they are originated from lichen and/or vascular plant debris from the pre- and inter-glacial periods in this region, whereas short-chain n-alkanoic acids are come from microalgae and cyanobacterial debris. CS-δ13C values suggest that they are derived from gymnosperms and/or C4 plants in the cold and dry environments of the pre- and inter-glacial periods of the McMurdo Dry Valleys region.
    Polar Science 08/2010; 4(2-4):187-196. DOI:10.1016/j.polar.2010.04.001
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    ABSTRACT: Antarctic climate changes influence environmental changes at both regional and local scales. Here we report Holocene paleolimnological changes in lake sediment core Sk4C-02 (length 378.0cm) from Lake Skallen Oike in the Soya Kaigan region of East Antarctica inferred from analyses of sedimentary facies, a range of organic components, isotope ratios of organic carbon and nitrogen, and carbon-14 dating by Tandetron accelerator mass spectrometry. The sediment core was composed of clayish mud (378.0–152.5cm) overlain by organic sediments (152.5cm-surface). The age of the surface and the core bottom were 150 (AD1950-1640) and ca. 7,030±73 calibrated years before present (cal BP), respectively, and the mean sedimentation rate was estimated to be 0.55mm/year. Multi-proxy analyses revealed that the principal environmental change in the core is a transition from marine to lacustrine environments which occurred at a depth of 152.5cm (ca. 3,590cal BP). This was caused by relative sea level change brought about by ongoing retreat of glaciers during the mid-Holocene warming of Antarctica, and ongoing isostatic uplift which outpaced changes in global (eustatic) sea level. The mean isostatic uplift rate was calculated to be 2.8mm/year. The coastal marine period (378.0–152.5cm, ca. 7,030–3,590cal BP) was characterized by low biological production with the predominance of diatoms. During the transition period from marine to freshwater conditions (152.5-approximately 135cm, ca. 3,590–3,290cal BP) the lake was stratified with marine water overlain by freshwater, with a chemocline and an anoxic (sulfidic) layer in the bottom of the photic zone. Green sulfur bacteria and Cryptophyta were the major photosynthetic organisms. The Cryptophyta appeared to be tolerant of the moderate salinity and stratified water conditions. The lacustrine period (approximately 135cm-surface, ca. 3,290cal BP-present) was characterized by high biological production by green algae (e.g. Comarium clepsydra and Oedegonium spp.) with some contributions from cyanobacteria and diatoms. Biological production during this period was 8.7 times higher than during the coastal marine period. KeywordsAntarctic lake-Paleolimnological change-Sediment core-Organic components-AMS carbon-14 dating-Uplifting rate
    Journal of Paleolimnology 08/2010; 44(2):677-693. DOI:10.1007/s10933-010-9448-y · 2.14 Impact Factor
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    ABSTRACT: Past changes in phytoplankton assemblages in Lake Baikal over the last 4.5 Ma, both in population and composition, are inferred from the downcore profiles of the relatively stable chlorophyll derivatives steryl esters of pyropheophorbides a and b (steryl chlorine esters; SCEs) in the 0–200 m section of the BDP-98 drill core, supplemented by the data on biogenic silica (BSi) and total organic carbon (TOC) contents. SCEs-a and -b dominate among sedimentary chlorophyll derivatives in the BDP-98 sediments except for the upper few meters, indicating their high stability during diagenetic alteration of sediments. The depth (age) profiles of SCEs-a are consistent with BSi and TOC profiles and are interpreted as reflecting primary productivity of the lake in the past. Baikal proxies reveal close correlation with marine oxygen isotope records (MIS stratigraphy). These observations confirm that climate change in the northern hemisphere has been a primary factor controlling the total phytoplankton productivity in Lake Baikal during the last several million years.Among SCEs-a, C30 (dinostanol)-SCE-a, a marker of dinoflagellates was identified by GC–MS analysis. SCE-b, a marker of green algae, was identified by its UV–vis spectrum. The ratio of C30-SCE-a to total SCEs-a (TSCEs-a) was higher during 4.5–4.2 and 1.7–1.3 Ma, suggesting that dinoflagellates proliferated preferentially in those periods. The early Pleistocene maximum of this ratio corresponds to the broad minimum of diatom abundance previously suggested to have recorded a prolonged regional cooling. An abrupt increase in the SCE-b/TSCEs-a ratio was observed at 2.5–2.6 Ma, indicating that green algae containing chlorophyll b have proliferated in Lake Baikal during this period. This interval has also been suggested to contain evidence for a significant regional cooling based on minima of diatom abundance and BSi in sediments. The depth profile of C27Δ5 (cholesterol)-SCE-a relative to TSCEs-a showed a trend similar to that of BSi, suggesting that C27Δ5-SCE-a/TSCEs-a ratio is a potential marker of diatoms in Lake Baikal.Certain mismatches between the Lake Baikal profiles of biological indicators and the marine oxygen isotope records, as well as the slight temporal offsets between different Lake Baikal biological marker signals suggest that the regional component of climatic and/or lacustrine environmental changes also have played a role in determining the composition of the Lake Baikal Plio-Pleistocene phytoplankton assemblage.
    Quaternary International 08/2009; DOI:10.1016/j.quaint.2009.02.004 · 2.13 Impact Factor
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    ABSTRACT: We analyzed photosynthetic pigments of algae and phototrophic bacteria in the 81-m sediment core (HDP-04) of Lake Hovsgol, NW Mongolia, to reconstruct the changes in algal assemblage and lake environment for the last 1Ma. In HDP-04, pheophytin a, pyropheophytin a, and steryl esters of pyropheophorbide a (steryl chlorin esters: SCEs-a) were detected as major chlorophyll a derivatives. They indicate that algal productivity fluctuated in response to changes in lacustrine environment, presumably in response to climatic changes. Significant concentrations of intact carotenoids, zexanthin, lutein, and β,β-carotene, as well as cis-isomers of zeaxanthin, diatoxanthin, alloxanthin, and β,β-carotene were found to be preserved in the sediments as old as 1Ma. The relative concentration of these algal carotenoids showed changes in algal assemblage for the last 1Ma. Besides algal pigments, bacteriochlorophylls e and isorenieratene, characterstic to brown-Chlorobium were detected transiently only at the sediment depth of 19–21m, providing evidence for the development of anoxia in photic zone because brown-Chlorobium requires hydrogen sulfide as an electron donor in their photosynthesis. The sediment layers between 21 and 52m where concentrations of algal carotenoids are higher than those of chlorophyll derivatives may correspond to the periods with shallower lake-water level because increased accumulation of algal carotenoids in surface sediments needs short transport pathway in the water column to evade abiotic/biotic oxidation during transportation.
    Quaternary International 08/2009; 205(1):74-83. DOI:10.1016/j.quaint.2009.02.007 · 2.13 Impact Factor
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    ABSTRACT: High-time resolution 14C dating of Lake Baikal sediment cores indicates negative and positive anomalies of calculated linear sedimentation rate (LSR; 1.1 and 35.6 cm/ka, respectively) during the period of climate transition from the last glacial to Holocene. The timing of the Lake Baikal apparent LSR anomalies is consistent with that of the changes in the atmospheric radiocarbon concentration (Δ14C) during Younger Dryas rapid cooling event. 14C dating of lipids in the Lake Baikal surface sediments revealed that the sources of sedimentary lipids were different in each basin. In the Northern Basin of Lake Baikal, the 14C age of total lipids from the surface sediment (4.0 14C ka) was found to be older than that of TOC (1.6 14C ka). By contrast, the 14C age of total lipids in the Southern Basin was younger than that of the TOC by ca. 0.7–3.0 ka.In the Lake Hovsgol sediment cores, ages of the main lithologic boundaries during the last glacial–interglacial transition were estimated based on new 14C data sets. TOC concentration in the cores started to rapidly increase at 13.8 ± 0.3 14C ka at the base of the basinwide finely laminated layer deposited during Bølling/Allerød. The base of the layer diatomaceous mud corresponds to the end of Younger Dryas event (10.6 ± 0.1 14C ka).
    Quaternary International 08/2009; 205(1):12-20. DOI:10.1016/j.quaint.2009.02.002 · 2.13 Impact Factor
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    ABSTRACT: Geochemistry of a sediment core from Lake Hovsgol, northwest Mongolia provides a continuous, 27-kyr history of the response of the lake and the surrounding catchment to climate change. Principle component (PC) analysis of 19 major and trace elements, total inorganic carbon (TIC), and total organic carbon (TOC) in the bulk sediment samples revealed that the 21 chemical components can be grouped into four assemblages—group-1: Na, Mg, Ca, Sr, and TIC, hosted in carbonate minerals (calcite, dolomite, and magnesian calcite); group-2: Ni, Cu, and Zn, recognized as biophilic trace metals, and TOC; group-3: Al, K, Ti, V, Fe, Rb, Cs, Ba, and Pb, composed of rock-forming minerals; and group-4: Cr, Mn, and As, sensitive to the redox condition of the sediment. The four element assemblages originated from three relevant processes. Group-1 and group-2 components are authigenic products and comprise the end member on the PC-1 score, whose variation reflects changes in the water volume, i.e. the balance between precipitation and evaporation (P/E). Group-3 components from detrital materials of the catchment contribute to the PC-2 score, whose variability indicates erosion/weathering intensity in the drainage basin, which might be controlled by the amount of vegetation cover associated with moisture change. The group-4 components of redox-sensitive elements contribute to the PC-3 score and are not an end member because of their small amount. The first two PC scores suggest a sequential record of paleo-moisture evolution in central Asia. The P/E balance in the Lake Hovsgol region, inferred from the PC-1 score, gradually increased during the glacial/interglacial transition. This resembles climate change of the North Atlantic region on the glacial–interglacial scale, but does not reflect the abrupt climate shifts such as the warm Bølling-Allerød and the cold Younger Dryas of the North Atlantic on the millennial scale. A periodic variation of ~8.7kyr was observed in the PC-2 score profile of detrital input to Lake Hovsgol over the last glacial and Holocene. The decrease in detrital input coincided with the copious supply of moisture from the Asian monsoon regime and the North Atlantic westerly winds to the Baikal drainage basin, which includes Lake Hovsgol. Our geochemical records from Lake Hovsgol demonstrate that the climate system of interior continental Asia was strongly influenced by change on both Milankovitch and sub-Milankovitch scales.
    Journal of Paleolimnology 02/2009; 43(2):369-383. DOI:10.1007/s10933-009-9336-5 · 2.14 Impact Factor
  • Genki I. MATSUMOTO · Yuki AKUTSU · Nobuki TAKAMATSU
    Japanese Journal of Limnology (Rikusuigaku Zasshi) 01/2006; 67(1):1-11. DOI:10.3739/rikusui.67.1
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    ABSTRACT: Organic components in sediment cores from Namazu Ike (lake) (length .* cm) and O «-ike (lake) (length -, cm) from Syowa Station area, Antarctica were studied to clarify their features in relation to paleoenvironmental changes, together with carbon-+. dating by Tandetron accelerator mass spectrometry. Namazu Ike sediment core was mainly composed of algal (mainly cyanobacteria) and aquatic moss debris, whereas O «-ike sediment core was comprised of coarse and fine sands with the influence of algal (mainly cyanobacteria) debris. The ages of core bottoms of Namazu Ike and O «-ike were estimated to be +//* and ,--* years before present (yBP), re-spectively. The sedimentation rates of Namazu Ike and O «-ike were calculated to be -* and /3 years/cm, respectively. Very high total organic carbon (TOC) contents (aver-age ,../) of Namazu Ike revealed that the sediment core was mainly composed of organic matter. Dramatic increase of TOC/total nitrogen ratios at a depth of ,/ cm in Namazu Ike strongly suggests that aquatic moss increased from ++** yBP to the core top. Changes in n-alkanes, n-alkanoic and n-alkenoic acids, and sterol compositions in the O «-ike sediment core, suggest that microbial composition changed considerably, but their source organisms are not clear and further studies are required.
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    ABSTRACT: Twelve strains of psychrophilic bacteria were isolated from cyanobacterial mat samples collected from various water bodies in the McMurdo Dry Valley region of Antarctica. All the isolates were Gram-negative, non-motile, coccoid, psychrophilic, halotolerant bacteria and had C(16 : 1)omega7c, C(17 : 1)omega8c and C(18 : 1)omega9c as the major fatty acids, ubiquinone-8 as the respiratory quinone and DNA G+C content of 41-46 mol%. Based on these characteristics, the isolates were assigned to the genus Psychrobacter. Based on their SDS-PAGE profiles, the 12 isolates could be categorized into three groups. Six isolates of Group I were identified as representing strains of Psychrobacter okhotskensis. However, using detailed phenotypic and chemotaxonomic characteristics and phylogenetic analysis based on their 16S rRNA gene sequences, strain CMS 39(T), the only strain from Group II, and strain CMS 56(T), a representative strain of Group III, were different from each other and from all recognized species of Psychrobacter. Therefore, it is proposed to classify CMS 39(T) (=DSM 15337(T)=MTCC 4208(T)) and CMS 56(T) (=DSM 15339(T)=MTCC 4386(T)) as representing the type strains of novel species of Psychrobacter, for which the names Psychrobacter vallis sp. nov. and Psychrobacter aquaticus sp. nov., respectively, are proposed.
    International Journal of Systematic and Evolutionary Microbiology 04/2005; 55(Pt 2):757-62. DOI:10.1099/ijs.0.03030-0 · 2.80 Impact Factor
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    ABSTRACT: Thirty-one bacteria that belonged to the genus Pseudomonas were isolated from cyanobacterial mat samples that were collected from various water bodies in Antarctica. All 31 isolates were psychrophilic; they could be divided into three groups, based on their protein profiles. Representative strains of each of the three groups, namely CMS 35(T), CMS 38(T) and CMS 64(T), were studied in detail. Based on 16S rRNA gene sequence analysis, it was established that the strains were related closely to the Pseudomonas fluorescens group. Phenotypic and chemotaxonomic characteristics further confirmed their affiliation to this group. The three strains could also be differentiated from each other and the closely related species Pseudomonas orientalis, Pseudomonas brenneri and Pseudomonas migulae, based on phenotypic and chemotaxonomic characteristics and the level of DNA-DNA hybridization. Therefore, it is proposed that strains CMS 35(T) (=MTCC 4992(T)=DSM 15318(T)), CMS 38(T) (=MTCC 4993(T)=DSM 15319(T)) and CMS 64(T) (=MTCC 4994(T)=DSM 15321(T)) should be assigned to novel species of the genus Pseudomonas as Pseudomonas antarctica sp. nov., Pseudomonas meridiana sp. nov. and Pseudomonas proteolytica sp. nov., respectively.
    International Journal of Systematic and Evolutionary Microbiology 06/2004; 54(Pt 3):713-9. · 2.80 Impact Factor
  • G S N Reddy · G I Matsumoto · S Shivaji
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    ABSTRACT: Strain CMS 21w(T) was isolated from a cyanobacterial mat sample taken from a pond located in the McMurdo Dry Valleys, Antarctica. Based on its phenotypic, chemotaxonomic and phylogenetic properties, strain CMS 21w(T) was identified as a member of the genus SPOROSARCINA: At the 16S rRNA gene level, CMS 21w(T) exhibited about 93-96 % similarity to all reported species of Sporosarcina and exhibited a maximum similarity of 96 % to both Sporosarcina globispora and Sporosarcina psychrophila. Based on more than 3 % difference at the 16S rRNA gene sequence level and the presence of distinct differences with respect to phenotypic, biochemical and chemotaxonomic features, strain CMS 21w(T) (=MTCC 4670(T)=DSM 15428(T)=CIP 107784(T)) is proposed as the type strain of a novel species of Sporosarcina, Sporosarcina macmurdoensis sp. nov.
    International Journal of Systematic and Evolutionary Microbiology 10/2003; 53(Pt 5):1363-7. DOI:10.1099/ijs.0.02628-0 · 2.80 Impact Factor
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    G S N Reddy · J S S Prakash · R Srinivas · G I Matsumoto · S Shivaji
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    ABSTRACT: Two unique psychrophilic strains (CMS 76rT and CMS 81yT) were isolated from a cyanobacterial mat sample from a pond in Wright Valley, McMurdo, Antarctica. Both isolates were assigned to the genus Leifsonia, since they were gram-positive, curved rods, non-motile, catalase-positive, contained DL-2,4-diaminobutyric acid, menaquinone MK-11, phosphatidylglycerol and diphosphatidylglycerol, had a high content of anteiso- and iso-branched fatty acids and had a DNA G + C content of 64-66 mol%. In addition, both isolates were related to the five reported species of Leifsonia at a level of about 95-96% 16S rDNA sequence similarity and differed from one another by 2.5%. Strains CMS 76rT and CMS 81yT also differed from one another in many other phenotypic characteristics and exhibited only 30% relatedness at the DNA-DNA level, thus indicating that they represent two different species. Furthermore, these two isolates also showed many distinct differences with respect to the reported species of Leifsonia in terms of their phenotypic characteristics, biochemical properties, chemotaxonomic features, sensitivity to various antibiotics and 16S rDNA similarity, clearly indicating that strains CMS 76rT (= MTCC 4210T = DSM 15304T = CIP 107783T) and CMS 81yT (= MTCC 4657T = DSM 15303T = CIP 107785T) represent the type strains of two novel species of Leifsonia, for which the names Leifsonia rubra sp. nov. and Leifsonia aurea sp. nov. are proposed.
    International Journal of Systematic and Evolutionary Microbiology 08/2003; 53(Pt 4):977-84. DOI:10.1099/ijs.0.02396-0 · 2.80 Impact Factor
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    ABSTRACT: Strain CMS 76orT, an orange-pigmented bacterium, was isolated from a cyanobacterial mat sample from a pond located in McMurdo Dry Valley, Antarctica. On the basis of chemotaxonomic and phylogenetic properties, strain CMS 76orT was identified as a member of the genus Kocuria. It exhibited a 16S rDNA similarity of 99.8% and DNA-DNA similarity of 71% with Kocuria rosea (ATCC 186T). Phenotypic traits confirmed that strain CMS 78orT and K. rosea were well differentiated. Furthermore, strain CMS 76orT could be differentiated from the other reported species of Kocuria, namely Kocuria kristinae (ATCC 27570T), Kocuria varians (ATCC 15306T), Kocuria rhizophila (DSM 11926T) and Kocuria palustris (DSM 11025T), on the basis of a number of phenotypic features. Therefore, it is proposed that strain CMS 76orT (= MTCC 3702T = DSM 14382T) be assigned to a novel species of the genus Kocuria, as Kocuria polaris.
    International Journal of Systematic and Evolutionary Microbiology 02/2003; 53(Pt 1):183-7. · 2.80 Impact Factor
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    ABSTRACT: The abundance of long-chain n-alkanes (>C20), n-C27, n-C29, and/or n-C31, and long-chain n-alkanoic acids, n-C26 and n-C28, reflects the fact that the dominant plants of the Lake Baikal basin were Pinus spp., Betula spp., Salix spp., etc. Normal-C29 alkane is mainly attributed to conifers and herbaceous plants, and has increased from 1 Myr ago to the present. C27 stanol/sterol ratios suggest that the lake bottom was oxic for 12-10 Myr BP, but anoxic for 8-6 Myr BP.
    Long Continental Records from Lake Baikal, 01/2003: pages 75-94; , ISBN: 978-4-431-67981-3
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    ABSTRACT: Thirteen orange-pigmented bacteria associated with cyanobacterial mat samples collected from four different lakes in McMurdo, Antarctica, were isolated. Twelve of the isolates, which were coccoid in shape, were very similar and possessed all the characteristics of the genus Planococcus and represented a new species, which was assigned the name Planococcus antarcticus sp. nov. (CMS 26or(T)). Apart from the phenotypic differences, P. antarcticus differed from all reported species of Planococcus by more than 2.5% at the 16S rRNA gene sequence level. In addition, at the DNA-DNA hybridization level, it exhibited very little similarity either with P. mcmeekinii (30%-35%), P. okeanokoites (26%-29%), or CMS 53or(T) (15%-25%), the three species with which it is closely related at the rRNA gene sequence level (2.5%-2.9%). P. antarcticus also showed only 2.5% difference in its 16S rRNA gene sequence compared with the P. alkanoclasticus sequence. But it was distinctly different from P. alkanoclasticus, which exists only as rods, is mesophilic and phosphatase positive, can hydrolyze starch, cannot utilize succinate, glutamate, or glucose, and cannot acidify glucose. Most important, P. antarcticus and P. alkanoclasticus varied distinctly in their fatty acid composition in that C(15:0), C(15:1), C(16:0), iso-C(16:1), and C(17:0) were present only in P. antarcticus but absent in P. alkanoclasticus. CMS 53or(T), the thirteenth isolate, was also identified as a new species of Planococcus and was assigned the name Planococcus psychrophilus sp. nov. This species was distinctly different from all the reported species, including the new species P. antarcticus, with respect to a number of phenotypic characteristics. At the 16S rRNA gene sequence level, it was closely related to P. okeanokoites (98.1%) and P. mcmeekinii (98%), but with respect to the DNA-DNA hybridization, the similarity was only 35%-36%. The type strain of P. antarcticus is CMS 26or(T) (MTCC 3854; DSM 14505), and that of P. psychrophilus is CMS 530r(T) (MTCC 3812; DSM 14507).
    Extremophiles 07/2002; 6(3):253-61. DOI:10.1007/s00792-001-0250-7 · 2.17 Impact Factor
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    ABSTRACT: Strain CMS 90rT, a red-pigmented bacterium, was isolated from a cyanobacterial mat sample from a pond located in McMurdo, Antarctica. Based on its chemotaxonomic and phylogenetic properties, strain CMS 90r(T) was identified as a member of group I of Arthrobacter. It shared 16S rDNA similarity of 98% with Arthrobacter oxydans ATCC 14358T and Arthrobacter polychromogenes ATCC 15216T, while DNA-DNA similarities determined for these three organisms were less than 70%. It also differed from all 17 reported Arthrobacter species with A3alpha-variant peptidoglycan in that it possessed a unique peptidoglycan (Lys-Gly-Ala3) and contained galactose, glucose, ribose and rhamnose as cell-wall sugars. These data and the presence of diagnostic phenotypic traits support the description of CMS 90r(T) as a novel species of Arthrobacter, for which the name Arthrobacter roseus sp. nov. is proposed. The type strain is strain CMS 90r(T) (= MTCC 3712T = DSM 14508T).
    International Journal of Systematic and Evolutionary Microbiology 06/2002; 52(Pt 3):1017-21. · 2.80 Impact Factor
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    G.S.N. Reddy · R K Aggarwal · G I Matsumoto · S Shivaji
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    ABSTRACT: CMS 19YT, a psychrophilic bacterium, was isolated from a cyanobacterial mat sample from a pond in Antarctica and was characterized taxonomically. The bacterium was aerobic, gram-positive, non-spore-forming, non-motile, exhibited a rod-coccus growth cycle and produced a yellow pigment that was insoluble in water but soluble in methanol. No growth factors were required and it was able to grow between 5 and 30 degrees C, between pH 6 and pH 9 and tolerated up to 11.5% NaCl. The cell wall peptidoglycan was Lys-Thr-Ala3 (the A3alpha variant) and the major menaquinone was MK-9(H2). The G+C content of the DNA was 64+/-2 mol%. The 16S rDNA analysis indicated that CMS 19YT is closely related to group I Arthrobacter species and showed highest sequence similarity (97.91%) with Arthrobacter agilis. Furthermore, DNA-DNA. hybridization studies also indicated 77% homology between CMS 19YT and A. agilis. It differed from A. agilis, however, in that it was psychrophilic, non-motile, yellow in colour, exhibited a rod-coccus growth cycle, had a higher degree of tolerance to NaCl and was oxidase- and urease-negative and lipase-positive. In addition, it had a distinct fatty acid composition compared to that of A. agilis: the predominant fatty acids were C15:0, anteiso-C15:0, C16:0, iso-C16:0, C17:0, anteiso-C17:0 and C18:0. It is proposed, therefore, that CMS 19YT should be placed in the genus Arthrobacter as a new species, i.e. Arthrobacter flavus sp. nov. The type strain of A. flavus is CMS 19YT (= MTCC 3476T).
    International Journal of Systematic and Evolutionary Microbiology 08/2000; 50 Pt 4(4):1553-61. DOI:10.1099/00207713-50-4-1553 · 2.80 Impact Factor
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    Nobuki  Takamatsu  · Naoyuki  Kato  · Genki I.  Matsumoto  · Tetsuya  Torii 
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    ABSTRACT: Lithium distributions in lake and pond waters of the McMurdo Dry Valleys of southern Victoria Land, Antarctica were studied to elucidate the origin of dissolved salts and the evolutionary history of the lakes and ponds. The EfLi [(Li/Cl)sample/(Li/Cl)seawater] values of the bottom waters in Lakes Bonney and Fryxell were higher than unity (EfLi=4–7), indicating that the salts originated from sea salts (probably relict seawater) and have been subsequently modified by the contribution of meltwaters containing atmospheric fallout and/or rock and soil weathering products. In contrast, extremely high Li concentrations with high EfLi values in the Don Juan Pond water (EfLi = 180) and the bottom waters of Lake Vanda (EfLi = 40) suggest that the salts originated from deep groundwaters influenced mainly by saline water-rock interactions, as supported by the dissolution experiments of granite in NaCl solution. The low Li concentrations of pond waters with high EfLi values in the Labyrinth indicate that the salts are derived from atmospheric fallout. The decrease of the EfLi values with the increase of Cl concentrations can be explained by the repeated cycles of the migration of Li into the ice phase and subsequent ablation of surface ice, as indicated by seawater freezing experiments.
    Antarctic Science 11/1998; 10(04):439 - 448. DOI:10.1017/S0954102098000534 · 1.61 Impact Factor

Publication Stats

1k Citations
120.22 Total Impact Points

Institutions

  • 1994–2014
    • Otsuma Women's University
      Edo, Tōkyō, Japan
  • 2002
    • Centre for Cellular and Molecular Biology
      Bhaganagar, Andhra Pradesh, India
  • 1990
    • Shonan Institute of Technology
      Fujisawa, Kanagawa, Japan
  • 1987–1990
    • The University of Tokyo
      • Department of Chemistry
      Tōkyō, Japan
  • 1977–1986
    • Tokyo Metropolitan University
      • Department of Chemistry
      Edo, Tōkyō, Japan