Xlfluor 2x 340

The details of the microscopic system for in vivo nanoimaging have been described in our previous studies [5 (link), 6 (link)]. In brief, an upright microscope (BX-51WI, Olympus Co., Tokyo, Japan) combined with a Nipkow confocal scanner (CSU21, Yokogawa Electric Co., Tokyo, Japan) and an electron multiplying CCD (EMCCD) camera (iXonEM+, Andor Technology Ltd, Belfast, Northern Ireland) were used at a 512 × 512 (or 512 × 170) pixel resolution at an exposure time of 28 (or 9.8) ms. A water immersion lens, either 60× (LUMPLFLN 60XW, N/A 1.00, Olympus Co.), 40× (LUMPLFLN 40XW, N/A 0.80, Olympus Co.), or 20× (XLUMPLFLN 20XW, N/A 1.00, Olympus Co.), and also a 2× lens (XLFluor 2X/340, N/A 0.14, Olympus Co.) were used to visualize the LV surface.
AcGFP-expressing myocytes were excited by a 488 nm laser light (HPU50211-PFS, Furukawa Electric Co., Tokyo, Japan), and the resultant fluorescence signals (emission filter: BA510–550, Olympus Co., Tokyo, Japan) were detected. In the experiments with CellMask, the heart was excited at 532 nm (MiniGreen FCIM-100; Snake Creek Lasers, Friendsville, PA, USA), and the resultant fluorescence signals (emission filter: BA575IF, Olympus Co.) were detected. When excited at 532 nm, the wavelength range for the detection of the fluorescence of CellMask was >575 nm.

Wide-field fluorescence imaging was performed on an Olympus Fluoview 1000 system (excitation wavelength at 488 nm, emission filter wavelength centered at 510 nm; Olympus, Corp.). The fluorescence images were captured by an EMCCD camera (iXon Ultra 888, Andor, Ltd.). A $10\times$ water immersion objective (0.3 NA, UMPLFLN, Olympus, Corp.) was used for GCaMP5G-expressing fly brain imaging. A $2\times$ objective (0.14 NA, XLFluor2X/340, Olympus, Corp.) was used for GCaMP6f-expressing mouse brain slice imaging.