The prevalence of diet-related obesity is increasing dramatically worldwide, making it important to understand the associated metabolic alterations in the liver. It is well known that obesity is a multifactorial condition that is the result of complex integration between many gene expressions and dietary factors. Obesity alone or in conjunction with other chronic diseases such as diabetes and insulin resistance causes many health problems and is considered a major risk factor for developing non-alcoholic steatohepatitis (NASH) and cirrhosis. In this study, we aimed to understand the molecular mechanisms underlying early hepatic changes in the pathophysiology of high-fat diet (HFD)-induced abdominal obesity in rats. Hepatic protein profiles of normal diet and HFD-induced obesity for 24 weeks were analysed using two-dimensional differential gel electrophoresis (DIGE) and protein identification by MS. Fifty-two proteins were identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF), and computer-assisted DIGE image software analysis showed that eighteen major proteins were significantly differentially expressed between comparable groups, with 2·0–4·0-fold change/more (P < 0·01). These proteins are regulated in response to a HFD, and differentially expressed proteins are involved in key metabolic pathways such as lipid metabolism, energy metabolism, detoxification, urea cycle and hepatic Ca homoeostasis. In addition, Western blot and immunohistochemistry of liver-specific arginase-1 (Arg-1) showed significant increased expression in the liver of high-fat-fed rats (P < 0·01). Further, Arg-1 expression was correlated with NASH patients with obesity-related fibrosis (F0–F4). It is concluded that high-fat content may affect changes in liver pathways and may be a therapeutic target for obesity-related liver disease. Arg-1 expressions may be a potential pathological marker for assessing the progression of the disease.

The gastrointestinal nematode Heligmosomoides polygyrus bakeri shows enhanced survival in mice with colitis. As the antibody response plays an important role in antiparasitic immunity, antibodies against male and female L4 H. polygyrus were examined in mice with and without colitis. Levels of specific antibodies in the mucosa and serum were determined by enzyme-linked immunosorbent assay and immunogenic proteins of male and female parasites were identified using 2D electrophoresis and mass spectrometry. The function of identified proteins was explored with Blast2Go. Nematodes in mice with colitis induced higher levels of specific immunoglobulin G (IgG1) and IgA, a lower level of IgE in the small intestine and a higher level of IgE in serum against female L4. Infected mice with colitis recognized 12 proteins in male L4 and 10 in female L4. Most of the recognized proteins from male L4 were intermediate filament proteins, whereas the proteins from female L4 were primarily actins and galectins. Nematodes from mice with colitis were immunogenically different from nematodes from control mice. This phenomenon gives new insights into helminth therapy as well as host–parasite interactions.

The main objectives of the study were to: (1) deeply analyse the serum protein composition of Equus caballus, (2) assess the effectiveness of the high-abundant protein depletion and improve the concentration of medium- and low-abundant proteins. The analysis were performed on the blood plasma of three healthy part-Arabian mares. The implementation of two-dimensional electrophoresis and matrix-assisted laser desorption/ionisation – time of flight mass spectrometry allowed us to establish a horse plasma proteome map. Serum proteins were resolved at pH 4 to 7, followed by 12% SDS-PAGE. As a result 136 spots were successfully identified, representing the products of 46 unique genes. Of these, 22 gene products have not been previously identified in horse serum/plasma samples using proteomic tools. Gene ontology analysis showed that almost 30% of all identified gene products belong to the coagulation and complement cascades. These results can undoubtedly serve as a useful and prospective prerequisite for the future analysis of horse plasma proteome changes in different physiological and pathophysiological conditions. The use of the medium- and low-abundant protein enrichment tool increased their abundance and allowed us to identify a higher number of protein gene products. The highest depletion efficiency was observed for the most abundant plasma proteins, that is albumin, IgG heavy chains and serotransferrin.

In the experiments reported here, we used the female ladybird Coccinella septempunctata L. as a model to identify diapause-associated proteins using proteomics technology. Our results indicated that protein expression patterns of diapausing and nondiapausing individuals were highly differentiated. A total of 58 spots showed significant differences in abundance (Ratio > 2 and P < 0.05) according to two-dimensional electrophoresis and GE Image Scanner III analysis. Sixteen protein spots were further investigated using mass spectrometry. Eight proteins were characterized, including chaperones and proteins involved in glucose metabolism, lipid metabolism, and the tricarboxylic acid cycle. Among these proteins, five proteins were upregulated in diapausing female adults, including a chaperone (Symbionin symL), malate dehydrogenase (putative), two proteins linked to lipid metabolism (unknown and conserved hypothetical protein) and phosphoglyceromutase (partial). By contrast, isocitrate dehydrogenase (RH49423p), fumarylacetoacetate hydrolase (AGAP001942-PA), and a putative medium chain acyl-CoA dehydrogenase were downregulated. These results contribute to the understanding of diapause mechanisms of the ladybird C. septempunctata and may suggest methods for improving the application of this natural enemy insect.

The yolk proteins of the silkworm, Bombyx mori, are important sources of nutrition and energy during embryo development. By analysing the yolk proteins from silkworm eggs, the composition and the metabolism of yolk proteins during embryo development stages can be studied at the proteome level. Yolk proteins were obtained from unfertilized eggs and eggs at different embryo development stages by dissection and then separated and analysed by two-dimensional electrophoresis and its corresponding image analysis system. It was discovered that over 200 proteins exist in mature silkworm eggs. Some specific spots of yolk proteins were found in different silkworm strains, while few differences in yolk proteins appeared during different development stages in the same silkworm strain. This result indicates that the silkworm embryo does not utilize yolk proteins selectively by absorbing one or some special proteins, but by absorbing the yolk protein grains one by one during development.