scholarly journals Recent colonization by a coastal plant of inland habitats at an ancient freshwater lake, Lake Biwa: multilocus sequencing and a demographic history ofLathyrus japonicus(Fabaceae)

2013 ◽  
Vol 3 (8) ◽  
pp. 2600-2611
Author(s):  
Tatsuo Ohtsuki ◽  
Hajime Ikeda ◽  
Hiroaki Setoguchi
2020 ◽  
Vol 85 ◽  
pp. 131-139
Author(s):  
S Shen ◽  
Y Shimizu

Despite the importance of bacterial cell volume in microbial ecology in aquatic environments, literature regarding the effects of seasonal and spatial variations on bacterial cell volume remains scarce. We used transmission electron microscopy to examine seasonal and spatial variations in bacterial cell size for 18 mo in 2 layers (epilimnion 0.5 m and hypolimnion 60 m) of Lake Biwa, Japan, a large and deep freshwater lake. During the stratified period, we found that the bacterial cell volume in the hypolimnion ranged from 0.017 to 0.12 µm3 (median), whereas that in the epilimnion was less variable (0.016 to 0.033 µm3, median) and much lower than that in the hypolimnion. Additionally, in the hypolimnion, cell volume during the stratified period was greater than that during the mixing period (up to 5.7-fold). These differences in cell volume resulted in comparable bacterial biomass in the hypolimnion and epilimnion, despite the fact that there was lower bacterial abundance in the hypolimnion than in the epilimnion. We also found that the biomass of larger bacteria, which are not likely to be grazed by heterotrophic nanoflagellates, increased in the hypolimnion during the stratified period. Our data suggest that estimation of carbon flux (e.g. bacterial productivity) needs to be interpreted cautiously when cell volume is used as a constant parametric value. In deep freshwater lakes, a difference in cell volume with seasonal and spatial variation may largely affect estimations.


2017 ◽  
Vol 5 (13) ◽  
Author(s):  
Yu Nakajima ◽  
Susumu Yoshizawa ◽  
Keiji Nakamura ◽  
Yoshitoshi Ogura ◽  
Tetsuya Hayashi ◽  
...  

ABSTRACT Here, we report the draft genome sequences of Tersicoccus phoenicis DSM 30849T, isolated from a spacecraft assembly cleanroom at the National Aeronautics and Space Administration (NASA), and Tersicoccus sp. strain Bi-70, isolated from Lake Biwa, the largest lake in Japan. These genome sequences facilitate our understanding of the adaptation of these closely related strains to different habitats.


2014 ◽  
Vol 2 (4) ◽  
pp. 1300100 ◽  
Author(s):  
Tatsuo Ohtsuki ◽  
Tasuku Shoda ◽  
Yuko Kaneko ◽  
Hiroaki Setoguchi

2012 ◽  
Vol 35 (4) ◽  
pp. 233-238 ◽  
Author(s):  
Hisaya Kojima ◽  
Masazumi Tsutsumi ◽  
Kanako Ishikawa ◽  
Tomoya Iwata ◽  
Marc Mußmann ◽  
...  

2019 ◽  
Author(s):  
Yusuke Okazaki ◽  
Yosuke Nishimura ◽  
Takashi Yoshida ◽  
Hiroyuki Ogata ◽  
Shin-ichi Nakano

SummaryMetagenomics has dramatically expanded the known virosphere, but freshwater viral diversity and their ecological interaction with hosts remain poorly understood. Here, we conducted a metagenomic exploration of planktonic dsDNA prokaryotic viruses by sequencing both virion (<0.22 μm) and cellular (0.22–5.0 μm) fractions collected spatiotemporally from a deep freshwater lake (Lake Biwa, Japan). This simultaneously reconstructed 183 complete (i.e., circular) viral genomes and 57 bacterioplankton metagenome-assembled genomes. Analysis of metagenomic read coverage revealed vertical partitioning of the viral community analogous to the vertically stratified bacterioplankton community. The hypolimnetic community was generally stable during stratification, but occasionally shifted abruptly, presumably due to lysogenic induction. Genes involved in assimilatory sulfate reduction were encoded in 20 (10.9%) viral genomes, including those of dominant viruses, and may aid viral propagation in sulfur-limited freshwater systems. Hosts were predicted for 40 (21.9%) viral genomes, encompassing 10 phyla (or classes of Proteobacteria) including ubiquitous freshwater bacterioplankton lineages (e.g., Ca. Fonsibacter and Ca. Nitrosoarchaeum). Comparison with viral genomes derived from published metagenomes revealed viral phylogeographic connectivity in geographically isolated habitats. Notably, analogous to their hosts, actinobacterial viruses were among the most diverse, ubiquitous, and abundant viral groups in freshwater systems, with potential high lytic activity in surface waters.


Sign in / Sign up

Export Citation Format

Share Document