scholarly journals Sperm metabolism is altered during storage by female insects: evidence from two-photon autofluorescence lifetime measurements in bedbugs

2015 ◽  
Vol 12 (110) ◽  
pp. 20150609 ◽  
Author(s):  
Klaus Reinhardt ◽  
Hans Georg Breunig ◽  
Aisada Uchugonova ◽  
Karsten König
Keyword(s):  
Fluorescence Lifetime ◽  
Sperm Cells ◽  
Fluorescence Lifetime Imaging ◽  
Two Photon ◽  
Lifetime Imaging ◽  
Photon Excitation ◽  
The Common ◽  
The Mean ◽  
The Difference ◽  
Male Genotype

We explore the possibility of characterizing sperm cells without the need to stain them using spectral and fluorescence lifetime analyses after multi-photon excitation in an insect model. The autofluorescence emission spectrum of sperm of the common bedbug, Cimex lectularius , was consistent with the presence of flavins and NAD(P)H. The mean fluorescence lifetimes showed smaller variation in sperm extracted from the male (tau m, τ m = 1.54–1.84 ns) than in that extracted from the female sperm storage organ (tau m, τ m = 1.26–2.00 ns). The fluorescence lifetime histograms revealed four peaks. These peaks (0.18, 0.92, 2.50 and 3.80 ns) suggest the presence of NAD(P)H and flavins and show that sperm metabolism can be characterized using fluorescence lifetime imaging. The difference in fluorescence lifetime variation between the sexes is consistent with the notion that female animals alter the metabolism of sperm cells during storage. It is not consistent, however, with the idea that sperm metabolism represents a sexually selected character that provides females with information about the male genotype.

scholarly journals Fluorescence Lifetime Imaging of Propranolol Uptake in Living Glial C6 Cells

2012 ◽  
Vol 27 ◽  
pp. 533-540 ◽  
Author(s):  
Roger Bisby ◽  
Stanley Botchway ◽  
Ana Crisostomo ◽  
Anthony Parker ◽  
Kathrin Scherer
Keyword(s):  
Fluorescence Lifetime ◽  
Fluorescence Lifetime Imaging ◽  
C6 Cells ◽  
Temperature Dependent ◽  
Two Photon ◽  
Lifetime Imaging ◽  
Photon Excitation ◽  
The Difference ◽  
Cellular Compartments ◽  
Intracellular Fluorescence

Uptake of theβ-blocker drug propranolol by living glial C6 cells has been observed using fluorescence lifetime imaging with two-photon excitation at 630 nm. Both uptake and release of propranolol occur within minutes and are temperature dependent, being about 5 times faster at 37°C than at 20°C. The intracellular fluorescence lifetime of propranolol is generally shorter than the value of 9.8 ns determined in dilute neutral aqueous solution, and the difference is ascribed to concentration quenching. Within the cells, propranolol is accumulated within intracellular acidic vesicles and the cytoplasm but is excluded from the cell nucleus. On incubation of cells in medium containing 100 μM propranolol, the drug is accumulated to reach intracellular concentrations up to 10 mM in a process that is believed to be driven by protonation within acidic cellular compartments.

Applications of Two-Photon Excitation Fluorescence Lifetime Imaging in Tumor Diagnosis

2018 ◽  
Vol 45 (2) ◽  
pp. 0207010
Author(s):  
李慧 Li Hui ◽  
夏先园 Xia Xianyuan ◽  
陈廷爱 Chen Tingai ◽  
余佳 Yu Jia ◽  
李曦 Li Xi ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Tumor Diagnosis ◽  
Fluorescence Lifetime Imaging ◽  
Two Photon ◽  
Lifetime Imaging ◽  
Photon Excitation ◽  
Two Photon Excitation

scholarly journals Depth Penetration and Detection of pH Gradients in Biofilms by Two-Photon Excitation Microscopy

1999 ◽  
Vol 65 (8) ◽  
pp. 3502-3511 ◽  
Author(s):  
Jurrien M. Vroom ◽  
Kees J. De Grauw ◽  
Hans C. Gerritsen ◽  
David J. Bradshaw ◽  
Philip D. Marsh ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Fluorescence Lifetime ◽  
Laser Scanning Microscopy ◽  
Fluorescence Lifetime Imaging ◽  
Ph Gradients ◽  
Two Photon ◽  
Lifetime Imaging ◽  
Microbial Biofilms ◽  
Photon Excitation ◽  
Two Photon Excitation

ABSTRACT Deep microbial biofilms are a major problem in many industrial, environmental, and medical settings. Novel approaches are needed to understand the structure and metabolism of these biofilms. Two-photon excitation microscopy (TPE) and conventional confocal laser scanning microscopy (CLSM) were compared quantitatively for the ability to visualize bacteria within deep in vitro biofilms. pH gradients within these biofilms were determined by fluorescence lifetime imaging, together with TPE. A constant-depth film fermentor (CDFF) was inoculated for 8 h at 50 ml · h−1 with a defined mixed culture of 10 species of bacteria grown in continuous culture. Biofilms of fixed depths were developed in the CDFF for 10 or 11 days. The microbial compositions of the biofilms were determined by using viable counts on selective and nonselective agar media; diverse mixed-culture biofilms developed, including aerobic, facultative, and anaerobic species. TPE was able to record images four times deeper than CLSM. Importantly, in contrast to CLSM images, TPE images recorded deep within the biofilm showed no loss of contrast. The pH within the biofilms was measured directly by means of fluorescence lifetime imaging; the fluorescence decay of carboxyfluorescein was correlated with biofilm pH and was used to construct a calibration curve. pH gradients were detectable, in both the lateral and axial directions, in steady-state biofilms. When biofilms were overlaid with 14 mM sucrose for 1 h, distinct pH gradients developed. Microcolonies with pH values of below pH 3.0 were visible, in some cases adjacent to areas with a much higher pH (>5.0). TPE allowed resolution of images at significantly greater depths (as deep as 140 μm) than were possible with CLSM. Fluorescence lifetime imaging allowed the in situ, real-time imaging of pH and the detection of sharp gradients of pH within microbial biofilms.

scholarly journals Two-photon excitation with pico-second fluorescence lifetime imaging to detect nuclear association of flavanols

2012 ◽  
Vol 719 ◽  
pp. 68-75 ◽  
Author(s):  
Irene Mueller-Harvey ◽  
Walter Feucht ◽  
Juergen Polster ◽  
Lucie Trnková ◽  
Pierre Burgos ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Fluorescence Lifetime Imaging ◽  
Two Photon ◽  
Lifetime Imaging ◽  
Photon Excitation ◽  
Nuclear Association ◽  
Two Photon Excitation
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