Aquaculture and commercial fisheries worldwide suffer from significant economic loss due to diseases of net-pen reared fish. In British Columbia, infectious hematopoietic necrosis (IHN) and bacterial kidney disease (BKD) epidemics occur because there are currently no commercially available drugs or fully licensed vaccines to treat these diseases. With a better understanding of the molecular mechanisms underlying these diseases, this circumstance might be significantly improved. In the present study, we have used a proteomics approach in an effort to identify and quantitate differentially expressed proteins in the liver and kidneys of diseased and healthy Atlantic salmon (Salmo salar). Isotope coded affinity tagging (ICAT), 2D gel electrophoresis, and multidimensional liquid chromatography coupled to tandem mass spectrometry (2D-LC MS/MS) were used to identify hundreds of differentially expressed proteins. While the direct significance of changes in expression levels of many proteins remains to be elucidated, others appear to be more clearly related to the infectious process. Examples of the latter are discussed here and include, a natural killer cell enhancement factor (NKEF), procathepsin L, superoxide-producing NADPH oxidase and interferon-induced viral resistance protein Mx (IFI-Mx).

Stomata on leaf epidermis formed by pairs of guard cells control CO(2) intake and water transpiration, and respond to different environmental conditions. Stress-induced stomatal closure is mediated via an intricate hormone network in guard cells. Although methyl jasmonate (MeJA) has been intensively studied for its function in plant defense, the molecular mechanisms underlying its function in stomatal movement are not fully understood. Here we report the effects of MeJA on Brassica napus stomatal movement and H(2)O(2) production. Using the isobaric tags for relative and absolute quantitation (iTRAQ) approach, we have identified 84 MeJA-responsive proteins in B. napus guard cells. Most of the genes encoding these proteins contain jasmonate-responsive elements in the promoters, indicating that they are potentially regulated at the transcriptional level. Among the identified proteins, five protein changes after MeJA treatment were validated using Western blot analysis. The identification of the MeJA-responsive proteins has revealed interesting molecular mechanisms underlying MeJA function in guard cells, which include homeostasis of H(2)O(2) production and scavenging, signaling through calcium oscillation and protein (de)phosphorylation, gene transcription, protein modification, energy balance, osmoregulation, and cell shape modulation. The knowledge of the MeJA-responsive proteins has improved our understanding of MeJA signaling in stomatal movement, and it may be applied to crop engineering for enhanced yield and stress tolerance.

The microsporidian parasite, Loma salmonae, is the causative agent of gill disease in both wild and netpen-reared salmonids worldwide. In this paper we report the finding of a rhamnose-binding lectin from steelhead trout, Oncorhynchus mykiss, which was found bound in high concentration to the surface coat of L. salmonae spores. SDS-PAGE, immunoblot, N-terminal sequencing and mass spectrometric analyses were used to determine that the dominant 24 kDa protein lectin observed on SDS-PAGE analysis of intact spore extracts is the O. tshawytscha variant of the previously identified rhamnose-binding lectin STL2 from rainbow trout, O. mykiss. Although the physiological role of these lectins has not been clearly delineated, they have been implicated in a variety of functions, including inhibition of pathogenic bacteria by opsonization and macrophage-mediated tumour lysis.

Mass spectrometry (MS)–based proteomics has become one of the most powerful tools for identifying expressed proteins, providing quick insights into molecular and cellular biology. Traditionally, proteins isolated by either one‐ or two‐dimensional gel electrophoresis are digested with a site specific protease. The resulting peptides are subject to one of two forms of analysis: (1) matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) MS, where a “mass fingerprint” of all the peptides in a sample is generated, or (2) electrospray ionization tandem MS (ESI‐MS/MS), where a mass fragmentation spectra is generated for each peptide in a sample. The resulting mass information is then compared to that of a theoretical database created with available genomic sequence information. This unit provides protocols for this type of assessment in embryonic stem cells (ESCs). Curr. Protoc. Stem Cell Biol. 2:1B.1.1‐1B.1.33. © 2007 by John Wiley & Sons, Inc.

Preeclampsia is a pregnancy-associated disorder that manifests as a sudden increase in maternal blood pressure accompanied by proteinuria. Because the placenta is a key organ in preeclampsia, we used proteomic and lipidomic analyses to compare placentae from preeclamptic and gestational age matched control pregnancies. Fatty acid binding protein 4 (FABP4), enoyl-CoA dehydrogenase and delta-3,5-delta-2,4-dienoyl-CoA isomerase had altered abundance in preeclamptic placentae compared to controls. FABP4 placental protein and RNA and plasma levels were all increased in early-onset preeclampsia (prior to 28 weeks gestation) compared to controls (6-fold, 3.3-fold and 3.5-fold respectively). After 28 weeks, FABP4 protein in control placenta and plasma increased to the same concentrations as in preeclampsia. Total tetracosapentaenoic acid in preeclamptic placentae was decreased to 0.6 of control levels before 28 weeks. The data indicate a disruption of fatty acid transport and metabolism in the placenta in early onset preeclampsia that is reflected in the maternal plasma.