Levels of ubiquitin (Ub)-conjugated proteins, as an index of misfolded or damaged proteins, were measured in notothenioid fishes, with both Antarctic (Trematomus bernacchii, T. pennellii, Pagothenia borchgrevinki) and non-Antarctic (Notothenia angustata, Bovichtus variegatus) distributions, as well as non-notothenioid fish from the Antarctic (Lycodichthys dearborni, Family Zoarcidae) and New Zealand (Bellapiscis medius, Family Tripterygiidae), in an effort to better understand the effect that inhabiting a sub-zero environment has on maintaining the integrity of the cellular protein pool. Overall, levels of Ub-conjugated proteins in cold-adapted Antarctic fishes were significantly higher than New Zealand fishes in gill, liver, heart and spleen tissues suggesting that life at sub-zero temperatures impacts protein homeostasis. The highest tissue levels of ubiquitinated proteins were found in the spleen of all fish. Ub conjugate levels in the New Zealand N. angustata, more closely resembled levels measured in other Antarctic fishes than levels measured in other New Zealand species, likely reflecting their recent shared ancestry with Antarctic notothenioids.

Understanding population dynamics in marine species has long been hindered by the inherent difficulties of studying species in which all or part of the life cycle is planktonic. Plankton sample processing is laborious and, due to morphological similarity between disparate taxa, often identifies zooplankton only to higher taxonomic levels. As a consequence, many scientific issues that require identification to species level are impossible to explore adequately. Several in situ hybridization protocols show promise for identifying marine larvae by color-coding them with taxon-specific, dye-labeled DNA probes. We adapted these protocols and coupled them with recent cell sorting technology to rapidly and accurately identify bivalve larvae from diverse plankton samples. We developed probes for 2 bivalve taxa: Musculista senhousia and the species complex Mytilus edulis/galloprovincialis/trossulus. Coupled fluorescence in situ hybridization and cell sorting (FISH-CS) separated M. galloprovincialis larvae from both oyster Crassostrea gigas larvae and from a mixed plankton/M. galloprovincialis sample. The number of false positives and false negatives was assessed by a PCR assay. Our FISH-CS method is robust to plankton autofluorescence and can be easily adapted to work with nearly any planktonic species or life stage of appropriate size. A green fluorescent DNA probe allows identification of mussel Mytilus galloprovincialis larvae in a plankton sample, despite autofluorescence in the plankton.

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