Surface muddy sediments with benthic diatoms were sucked up by using a glass tube from an intertidal sand beach in the Huiquan Bay, Qingdao City. The diatom cells were isolated using capillary pipettes and cultivated in 250 mL cell culture flasks with 100 mL F/2 medium. Cultures were maintained at 20–22 °C under a low light intensity (25–30 µmol photo/m2/s) with a light/dark cycle of 12:12 h. Five millilitres of diatom culture were fixed with 2.5% glutaraldehyde and then cleaned with hydrogen peroxide to remove organic components of frustules [33 (link)].
Morphological observation followed the method described in our previous study [34 (link)]: for light microscopy (LM) observation, cleaned samples were pipetted onto the coverslips, air-dried, and mounted on glass slides with Mountmedia (Wako Pure Chemical Industries, Ltd., Osaka, Japan). LM microphotographs of cleaned frustules were taken by using a Zeiss Imager Z2 microscope (Carl Zeiss Microimaging GmbH, Jena, Germany) with differential interference contrast (DIC). For scanning electron microscopy (SEM) observation, cleaned frustules were placed on round coverslips, air-dried, and coated with osmium. SEM observation was performed by using a Hitachi S–4800 (Hitachi, Ltd., Tokyo, Japan).
Morphological observation followed the method described in our previous study [34 (link)]: for light microscopy (LM) observation, cleaned samples were pipetted onto the coverslips, air-dried, and mounted on glass slides with Mountmedia (Wako Pure Chemical Industries, Ltd., Osaka, Japan). LM microphotographs of cleaned frustules were taken by using a Zeiss Imager Z2 microscope (Carl Zeiss Microimaging GmbH, Jena, Germany) with differential interference contrast (DIC). For scanning electron microscopy (SEM) observation, cleaned frustules were placed on round coverslips, air-dried, and coated with osmium. SEM observation was performed by using a Hitachi S–4800 (Hitachi, Ltd., Tokyo, Japan).
Free full text: Click here
