Яйца и внеклеточной покрытия вокруг яйца часто релизе пептидов, белков и малых молекул, которые взаимодействуют со спермой, чтобы вести их к яйцеклетке тем самым способствуя оплодотворению. Использование спермы лягушки мы описать и сравнить два класса тесты используются для обнаружения спермы chemoattraction – сперма накопления анализы и анализы спермы слежения.
Sperm chemoattraction in invertebrates can be sufficiently robust that one can place a pipette containing the attractive peptide into a sperm suspension and microscopically visualize sperm accumulation around the pipette1. Sperm chemoattraction in vertebrates such as frogs, rodents and humans is more difficult to detect and requires quantitative assays. Such assays are of two major types – assays that quantitate sperm movement to a source of chemoattractant, so-called sperm accumulation assays, and assays that actually track the swimming trajectories of individual sperm.
Sperm accumulation assays are relatively rapid allowing tens or hundreds of assays to be done in a single day, thereby allowing dose response curves and time courses to be carried out relatively rapidly. These types of assays have been used extensively to characterize many well established chemoattraction systems – for example, neutrophil chemotaxis to bacterial peptides and sperm chemotaxis to follicular fluid. Sperm tracking assays can be more labor intensive but offer additional data on how chemoattractancts actually alter the swimming paths that sperm take. This type of assay is needed to demonstrate the orientation of sperm movement relative to the chemoattrractant gradient axis and to visualize characteristic turns or changes in orientation that bring the sperm closer to the egg.
Here we describe methods used for each of these two types of assays. The sperm accumulation assay utilized is called a “two-chamber” assay. Amphibian sperm are placed in a tissue culture plate insert with a polycarbonate filter floor having 12 μm diameter pores. Inserts with sperm are placed into tissue culture plate wells containing buffer and a chemoatttractant carefully pipetted into the bottom well where the floor meets the wall (see Fig. 1). After incubation, the top insert containing the sperm reservoir is carefully removed, and sperm in the bottom chamber that have passed through the membrane are removed, pelleted and then counted by hemocytometer or flow cytometer.
The sperm tracking assay utilizes a Zigmond chamber originally developed for observing neutrophil chemotaxis and modified for observation of sperm by Giojalas and coworkers2,3. The chamber consists of a thick glass slide into which two vertical troughs have been machined. These are separated by a 1 mm wide observation platform. After application of a cover glass, sperm are loaded into one trough, the chemoattractant agent into the other and movement of individual sperm visualized by video microscopy. Video footage is then analyzed using software to identify two-dimensional cell movements in the x-y plane as a function of time (xyt data sets) that form the trajectory of each sperm.
Хемотаксис клеток движущихся либо амебоидных движения или жгутиков питание плавание содержится во многих биологических условий и изучение этого явления требует наличие практичного и надежного анализа. Некоторые примеры этого явления, такие как привлечение спермы яйца морского ежа ?…
The authors have nothing to disclose.
Мы благодарим Bioimaging Кека лаборатории за использование их видео работы станции микроскопии. Это исследование было поддержано грантом NSF IBN-0615435.
Name of Item | Company | Catalogue Number | Comments |
24-well plates | Becton-Dickenson | 35/1147 | |
12 mm outer diameter inserts with 12 μm pore membrane | Millipore | PIXP01250 | We previously used Costar-Corning transwell plate #3403 -now discontinued |
Zigmond chamber | Neuroprobe | Z02 | |
Silicone oil | General Electric | SF1154 | Equivalent to Dow Corning 550 Fluid |
Image J software | Wayne Rasband, Research Services Branch, National Institute of Mental Health | Free download at http://rsbweb.nih.gov/ij |
Java program that runs on Windows, Linux and Mac |
MtrackJ software | Erik Meijering/ Imagescience/ Biomedical Imaging Group, Erasmus MC – University Medical Center Rotterdam |
Free download at http://www.imagescience.org/meijering/software/mtrackj/ | Java program that runs on Windows, Linux and Mac |
Virtual Dub software | GNU General Public Licensed software | Free download via http://www.virtualdub.org/index.html | Setup instructions at the Image J website under plugins; for Windows only |
cellSens software | Olympus | See website: http://www.olympusamerica.com/seg_section/product.asp?product=1070 | Controls and acquires images from a variety of cameras. Also has image processing capability |