Sinking of Four Species of Living Diatom Cells Directly Observed by a “Tumbled” Optical Microscope

Hamano, Ryo; Shoumura, Shingo; Takeda, Yuto; Yamazaki, Tokio; Hirayama, Kota; Hanada, Yasutaka; Mayama, Shigeki; Takemura, Masaharu; Lin, Huei‐Jeng; Umemura, Kazuo

doi:10.1017/s1431927621012150

Cited by 8 publications

(14 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We underline that the results presented here are the average of at least three replicas and further measurements were performed at higher diatom concentrations, providing the same τ parameters. Given the importance to directly assess sinking capacity in phytoplankton, numerous efforts were made to figure out a suitable method ( Walsby and Holland, 2006 and reference therein; Gemmell et al., 2016 ; Bannon and Campbell, 2017 ; Hamano et al., 2021 ); the present study confirms the feasibility of using DLS to achieve this purpose.…”

Section: Discussionsupporting

confidence: 75%

“…Because the τ parameter is related to the necessary time to sink, clearly related to chemical physical properties of each particular diatom, it is inversely proportional to sedimentation rate. We considered the recent results obtained by Hamano et al. (2021) , where four different diatom species’ experimental velocity rates had been estimated by a sophisticated homemade optical microscope system.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Integrative effects of morphology, silicification, and light on diatom vertical movements

et al. 2023

View full text Add to dashboard Cite

Diatoms represent the most abundant and diversified class of primary producers in present oceans; their distinctive trait is the ability to incorporate silicic acid in a silica outer shell called frustule. Numerous adaptative functions are ascribed to frustules, including the control of vertical movements through the water column; this indirectly determines cell access to fundamental resources such as light and nutrients, and favors diatom escape from predators. At the same time, light guides phototroph movements in the water column by affecting cell density (e.g., by modulating Si deposition in diatoms, vacuole volume, and/or solution). We investigated how the tremendous diversity in morphology and silicification that characterizes the frustule and the crucial role of light in diatom spatial distribution govern diatom sinking capacity. To test their integrative effects, we acclimated four diatoms distinguished by frustule traits (Chaetoceros muelleri, Conticribra weissflogii, Phaeodactylum tricornutum, and Cylindrotheca fusiformis) to different light conditions and evaluated their physiological performance in terms of growth, elemental composition, morphological changes, and their in vivo sinking capacity. What emerged from this study was that silicification, more than other morphological characteristics, controls species vertical movements, while a higher energy availability enhances cell floating independently from the silica content.

show abstract

Section: Discussionsupporting

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Integrative effects of morphology, silicification, and light on diatom vertical movements

et al. 2023

View full text Add to dashboard Cite

show abstract

“…The major pores were approximately 480 ± 30 and 140 ± 30 nm in length and width, respectively. In general, the specific gravity of frustules is around 1.3 , and that of silica beads is approximately 2.2–4.3 . Because specific gravity of frustules is smaller than that of other typical micron-sized objects, they are widely used to make micron-sized biodevices.…”

Section: Resultsmentioning

confidence: 99%

“…Isolated Navicula sp. cells were cultured in Guillard’s (F/2) culture medium (G9903; Sigma-Aldrich, Munich, Germany) with Daigo artificial seawater (395-01343; Nihon Pharmaceutical, Tokyo, Japan). , Frustules from diatom cells in suspensions were treated with nitric acid. The cell suspensions were replaced with pure water by centrifugation (1630 g , 5 min, five times).…”

Section: Methodsmentioning

confidence: 99%

Attachment of DNA-Wrapped Single-Walled Carbon Nanotubes (SWNTs) for a Micron-Sized Biosensor

et al. 2022

Self Cite

View full text Add to dashboard Cite

We fabricated a micron-sized biodevice based on the near-infrared photoluminescence (PL) response of single-walled carbon nanotubes (SWNTs). Various biosensors using the unique optical responses of SWNTs have been proposed by many research groups. Most of these employed either colloidal suspensions of dispersed SWNTs or SWNT films on flat surfaces, such as electrodes. In this study, we attached DNA-wrapped SWNTs (DNA-SWNTs) to frustule (micron-sized nanoporous biosilica) surfaces, which were purified from cultured isolated diatoms. After the injection of an oxidant and a reductant, the SWNTs on the frustules showed prominent PL responses. This suggests that the biodevice functions as a micron-sized redox sensor. Frustules can be easily suspended in aqueous solutions because of their porous structures and can easily be collected as pellets by low-speed centrifugation. Thus, the removal of unbound SWNTs and the recovery of the fabricated DNA-SWNT frustules for reuse were achieved by gentle centrifugation. Our proposal for micron-sized SWNT biodevices would be helpful for various biological applications.

show abstract

“…Nitzschia sp. were collected from Okinoshima Island in the Chiba Prefecture and subcultured several times using Guillard's (F/2) culture medium (G9903; Sigma-Aldrich, Munich, Germany) with Daigo artificial seawater (395-01343; Nihon Pharmaceutical, Tokyo, Japan) for approximately 2 months (Murase et al, 2011(Murase et al, , 2012Umemura et al, 2015;Ide et al, 2020;Shoumura et al, 2020;Hamano et al, 2021).…”

Section: Methodsmentioning

confidence: 99%

An Efficient Method of Observing Diatom Frustules via Digital Holographic Microscopy

Saitô

Kitamura

Ide

et al. 2022

Microscopy and Microanalysis

Self Cite

View full text Add to dashboard Cite

Herein, we propose a convenient method to enable pretreatment of target objects using digital holographic microscopy (DHM). As a test sample, we used diatom frustules (Nitzschia sp.) as the target objects. In the generally used sample preparation method, the frustule suspension is added dropwise onto a glass substrate or into a glass chamber. While our work confirms good observation of purified frustules using the typical sample preparation method, we also demonstrate a new procedure to observe unseparated structures of frustules prepared by baking them on a mica surface. The baked frustules on the mica surface were transferred to a glass chamber with 1% sodium dodecyl sulfate solution. In this manner, the unseparated structures of the diatom frustules were clearly observed. Furthermore, metal-coated frustules prepared by sputtering onto them on a mica surface were also clearly observed using the same procedure. Our method can be applied for the observation of any target object that is pretreated on a solid surface. We expect our proposed method to be a basis for establishing DHM techniques for microscopic observations of biomaterials.

show abstract

Sinking of Four Species of Living Diatom Cells Directly Observed by a “Tumbled” Optical Microscope

Abstract: Abstract

Cited by 8 publications

References 38 publications

Integrative effects of morphology, silicification, and light on diatom vertical movements

Integrative effects of morphology, silicification, and light on diatom vertical movements

Attachment of DNA-Wrapped Single-Walled Carbon Nanotubes (SWNTs) for a Micron-Sized Biosensor

An Efficient Method of Observing Diatom Frustules via Digital Holographic Microscopy

Contact Info

Product

Resources

About