CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Reproduction, Fertility and Development   
Reproduction, Fertility and Development
  Vertebrate reproductive science and technology
blank image Search
blank image blank image
blank image
  Advanced Search

Journal Home
About the Journal
Editorial Structure
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Research Fronts
Virtual Issues
Sample Issue
For Authors
General Information
Submit Article
Author Instructions
Open Access
Awards and Prizes
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates
Library Recommendation

blue arrow e-Alerts
blank image
Subscribe to our email Early Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter logo LinkedIn

red arrow Connect with SRB
blank image
facebook TwitterIcon

Affiliated Societies

RFD is the official journal of the International Embryo Transfer Society and the Society for Reproductive Biology.

Article << Previous     |     Next >>   Contents Vol 22(1)


A. Al Naib A, M. Wallace A, L. Brennan A, T. Fair A and P. Lonergan A

University College Dublin, Ireland

Export Citation


Metabolomics is the study of small molecules or metabolites present in biological samples. The metabolism of the bovine embryo is marked by a transition from the oocyte and early stage embryo, which are entirely dependent on TCA cycle activity for the generation of ATP, toward a significantly greater input of glycolysis during morula compaction and blastocyst formation. The aim of this study was to describe the changes in metabolic profiles of bovine embryos across pre-implantation development. Five pools of 100 embryos at the 2- to 4-cell, 8-cell, 16-cell, morula, and blastocyst stages (i.e. 500 embryos in total per developmental stage) were produced by IVM, IVF, and IVC. Each pool was snap frozen and stored at -80°C until analysis. Extraction of metabolites was performed using 6% perchloric acid. 1H spectra were acquired on a 600-MHz Varian NMR spectrometer operating at 25°C (Varian Inc., Palo Alto, CA, USA). All spectra were processed, baseline corrected, and integrated into bins of 0.02 ppm width. The water region was excluded and data were normalized to the sum of the spectral integral. Data were analyzed using multivariate statistics. Principal component analysis (PCA), an unsupervised pattern recognition technique, was performed initially to assess variation and expose any trends or outlying data. Partial least squares-discriminant analysis (PLS-DA) was subsequently performed to define the maximum separation between the different developmental stages. Data were visualized by constructing principal component scores and loadings plots, where each point on the score plot represented an individual sample and each point on the loadings plot represented a single 1H NMR spectral region. The quality of all models was judged by the goodness-of-fit parameter (R2) and the predictive ability parameter (Q2). PCA analysis of all the data showed distinct separation of the 2- to 4-cell, and 8-cell (i.e. pre-embryonic genome activation, EGA) from 16-cell, morula and blastocyst (i.e. post-EGA) extracts. Pair-wise comparisons between successive developmental stages were performed. PCA analysis showed separation of 2- to 4-cell and 8-cell extracts. A PLS-DA was built with an R2 of 0.97 and a Q2 of 0.55. The main discriminating metabolites were acetate, acetoacetate, and an unidentified peak at 1.25 ppm. Similarly, PCA analysis showed separation of 8-cell and 16-cell embryo extracts. A PLS-DA model was built with an R2 of 0.99 and a Q2 of 0.92. The discrimination was due to higher levels of acetate and an unidentified peak in 8-cell extracts and the appearance of a new peak in 16-cell extracts, tentatively assigned to oxalacetate. PCA analysis showed no separation of the 16-cell, morula, and blastocyst extracts. In conclusion, 1H NMR spectroscopy allows the simultaneous measurement of small-molecular-weight molecules in complex biological samples. Given that the metabolome is downstream of gene function it may represent a superior measure of cellular activities compared to transcriptomic and proteomic approaches.

Supported by Science Foundation Ireland (07/SRC/B1156).

Reproduction, Fertility and Development 22(5305) 230–230   http://dx.doi.org/10.1071/RDv22n1Ab143
Published online: 08 December 2009

Top  Email this page

Legal & Privacy | Contact Us | Help


© CSIRO 1996-2016