Reconstructing labroid evolution with single-copy nuclear DNA.

Fifteen per cent of all living fishes are united in a single suborder (Labroidei) and display a dazzling array of behavioural and ecological traits. The labroids are considered monophyletic and members share a pharyngeal jaw apparatus (PJA) modified for crushing and processing prey. Outside of the explicitly functional PJA, there is no corroborative evidence for a monophyletic Labroidei. Here, we report the first molecular phylogenetic analysis of the suborder. Contrary to morphology-based phylogenies, our single-copy nuclear DNA data do not support labroid families as a natural group. Our data indicate that pharyngognathy has evolved independently among labroid families and that characters of the PJA are not reliable markers of perciform evolution. This work ''crushes'' conventional views of fish phylogeny and should engender novel concepts of piscine life history evolution.     

Diminished Reovirus Capsid Stability Alters Disease Pathogenesis and Littermate Transmission

Reovirus is a nonenveloped mammalian virus that provides a useful model system for studies of viral infections in the young. Following internalization into host cells, the outermost capsid of reovirus virions is removed by endosomal cathepsin proteases. Determinants of capsid disassembly kinetics reside in the viral σ3 protein. However, the contribution of capsid stability to reovirus-induced disease is unknown. In this study, we found that mice inoculated intramuscularly with a serotype 3 reovirus containing σ3-Y354H, a mutation that reduces viral capsid stability, succumbed at a higher rate than those infected with wild-type virus. At early times after inoculation, σ3-Y354H virus reached higher titers than wild-type virus at several sites within the host. Animals inoculated perorally with a serotype 1 reassortant reovirus containing σ3-Y354H developed exaggerated myocarditis accompanied by elaboration of pro-inflammatory cytokines. Surprisingly, unchallenged littermates of mice infected with σ3-Y354H virus displayed higher titers in the intestine, heart, and brain than littermates of mice inoculated with wild-type virus. Together, these findings suggest that diminished capsid stability enhances reovirus replication, dissemination, lethality, and host-to-host spread, establishing a new virulence determinant for nonenveloped viruses.     

Stable ester conjugate between the Saccharomyces cerevisiae RAD6 protein and ubiquitin has no biological activity.

The RAD6 gene of Saccharomyces cerevisiae, which encodes a ubiquitin-conjugating enzyme, is required for DNA repair, DNA damage-induced mutagenesis and sporulation. To evaluate the biological relevance of the thioester adduct between RAD6 protein and ubiquitin, formed as an obligatory, transient intermediate during ubiquitin conjugation to substrates, we altered cysteine 88 in RAD6 to serine. Esterification with ubiquitin occurs at serine 88 in the mutant protein, but conjugation of ubiquitin to the test substrate histone H2A is inactivated. Phenotypically, strains harboring the rad6 Ser88 allele are indistinguishable from rad6 deletion (rad6 delta) mutant cells. These findings argue against ligation of ubiquitin at cysteine 88 acting as a functional switch of a cryptic biochemical activity in RAD6.     

Isomeric lipid signatures reveal compartmentalized fatty acid metabolism in cancer

The cellular energy and biomass demands of cancer drive a complex dynamic between uptake of extracellular FAs and their de novo synthesis. Given that oxidation of de novo synthesized FAs for energy would result in net-energy loss, there is an implication that FAs from these two sources must have distinct metabolic fates; however, hitherto, all FAs have been considered part of a common pool. To probe potential metabolic partitioning of cellular FAs, cancer cells were supplemented with stable isotope-labeled FAs. Structural analysis of the resulting glycerophospholipids revealed that labeled FAs from uptake were largely incorporated to canonical (sn-) positions on the glycerol backbone. Surprisingly, labeled FA uptake also disrupted canonical isomer patterns of the unlabeled lipidome and induced repartitioning of n-3 and n-6 PUFAs into glycerophospholipid classes. These structural changes support the existence of differences in the metabolic fates of FAs derived from uptake or de novo sources and demonstrate unique signaling and remodeling behaviors usually hidden from conventional lipidomics.     

Application of a new slot comb to electrophoretic analysis.

In the present experiment, a new slot comb was designed in order to form a wide and sloped sample well on the stacking gel of electrophoresis. Using this slot comb, a gradient of the reagent layer of interest can be easily formed transversely on the gel that is perpendicular to the direction of electrophoresis. Thus, the protein sample overlaid on the agent migrates across the gradient layer during electrophoresis to produce a continuous electrophoretic band reflecting the interaction between the protein and reagent. This new slot comb (tentatively called slope comb) was applied to the following two experiments. In the first experiment, in combination with this comb and a reducing agent, 2-mercaptoethanol, the reducing steps of cross-linked axonemal proteins with o-iodosobenzoic acid (OIBA) were analyzed electrophoretically, enabling visualization of the reducing pattern of each axonemal protein in a single experiment. The results obtained indicate that alpha and beta tubulins are cross-linked differently by OIBA. In the second experiment, the formation of the Ca2+ gradient layer using this slope comb could electrophoretically differentiate the Ca2+ sensitivity of three Ca(2+)-binding proteins.     

Immersion staining of coarse fish in the Thames

Thirty-one vital dyes were screened for marking bleak, roach and gudgeon by total body immersion in aqueous solutions of the dye. Only six dyes stained without killing, and of these Nile blue, neutral red and Bismarck brown were used successfully in the field. This approach to estimation of population size was abandoned because (1) the toxicity of the dyes varied at different times of year, (2) the numbers needed for release were impractically high and (3) fingerlings showed extremely high mortality on handling.     

Chromatin degradation in white blood cells of irradiated rats

A study was made of the dose-time relationship during chromatin degradation in white blood cells of non-irradiated and irradiated rats. There was a linear increase in the release of PDN from leukocytes 1,2 and 3 days after irradiation (1-3 Gy) followed by the deceleration of the chromatin degradation at doses exceeding 3 Gy.