This study aimed to identify proteins differentially expressed in the human endometrium between the proliferative and secretory phases of normal menstrual cycles by 2D differential in-gel electrophoresis (DIGE). A total of 196 out of 1017 spots were differentially expressed (p < 0.05). Mass spectrometry identified 76 proteins representing 41 different gene products. Immunohistochemistry confirmed the observed changes in 3 representative proteins (Rho-GDIalpha, CLIC1, PGRMC1). Biological pathway analysis identified the Jnk and EGF signaling pathways as key regulators of protein expression in the midsecretory phase of endometrial proteome.

Cereal Chem. 86(3):281-289Germination in the soft wheat (Triticum aestivum L.) cultivar Rosella was followed for three days after imbibition by proteomic analysis of the germ tissue. Two-dimensional electrophoresis was performed in triplicate for proteins extracted from embryos dissected from mature grain and from grains germinated for 1, 2, and 3 days. For this period, 63 proteins (in 86 spots) in the germ were identified as decreasing in abundance, 35 proteins (in 60 spots) as increasing in abundance, and 28 proteins (in 39 spots) as exhibiting no significant abundance change. Proteins with significant abundance changes are discussed in relation to physiology; these include proteases, amylases and amylase inhibitors, enzymes in lipid metabolism, proteins related to water stress, cell wall hydrolases, oxalate oxidase, and H + -ATPases. Functions associated with proteins synthesized during the germination period are inconsistent with the embryo of mature grain being fully primed for germination.Germination involves reanimation of the embryo from a state of quiescence in mature seed to a state of highly active metabolism. Germination is triggered by rehydration at a temperature within an acceptable range, and requires adequate rates of gas exchange. In grasses such as wheat, abundant stores of starch and protein are contained in the starchy endosperm, which loses its cellular structure as grains reach maturity, but is surrounded by a layer of intact aleurone cells. Breakdown of storage carbohydrates and proteins occurs during germination to provide nutrition for the rapidly growing embryo before autotrophy can begin.An extensive literature describes the storage proteins of the wheat endosperm, their variation between cultivars, and their influence on flour quality (see review in Singh et al [2005]). Many aspects of the biochemistry and control of storage protein (and starch) breakdown are well understood for wheat and other monocotyledonous cereals. In the earliest stage of germination, imbibition results in the synthesis of gibberellic acid (GA) by the embryo. This hormone acts to promote expression of genes for hydrolytic enzymes produced in the aleurone and scutellum. In the embryo, repair and synthesis of mitochondria and activation of respiration allows mobilization of the embryo's internal reserves of proteins, lipids, and carbohydrates.In this study, we focus on proteomic changes in the embryo that occur throughout the germination period, a relatively unexplored area. We aim to further our understanding of metabolic changes occurring during germination by correlating changes in protein abundance with physiological processes associated with germination and very early seedling development. Many questions concerning the role and status of proteins in the wheat embryo during germination remain unresolved. For example, to what extent is the embryo of the mature grain primed for germination? What types of proteins required for germination are synthesized during grain development or after imbibition? To what exten...

Proteome analyses were carried out on commercial wheat germ of mature grain from the biscuit-making wheat cultivar, Rosella. Wheat germ protein extracts were fractionated by two-dimensional gel electrophoresis across two different immobilised pH gradients: pH 4.0-7.0 and 6.0-9.0. A total of 612 individual protein spots were excised from the gels and characterised by peptide mass fingerprinting. From these analyses, 347 individual proteins were identified from protein sequence database interrogation, and 301 different types of protein were catalogued according to protein function. The remaining 265 protein spots gave poor or no matches to proteins in the databases and were not identified in this study. Six different classes of enzymes were identified in the germ, many of them having roles in the mobilisation of energy reserves for germination. Abundantly expressed enzyme classes include the oxidoreductases, transferases and hydrolases. A comparison was also made between the major protein classes expressed in the germ and protein classes expressed in the endosperm from previous proteomic work. This study contributes significantly to our knowledge of protein expression and heterogeneity in the germ of wheat grain and forms the basis for future studies in regard to the characterisation of proteins during the initial stages of germination.