Using systematic conservation planning to establish management priorities for freshwater salmon conservation,Matanuska‐Susitna Basin,AK, USA

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Genomic signatures predict migration and spawning failure in wild Canadian salmon

Long-term population viability of Fraser River sockeye salmon (Oncorhynchus nerka) is threatened by unusually high levels of mortality as they swim to their spawning areas before they spawn. Functional genomic studies on biopsied gill tissue from tagged wild adults that were tracked through ocean and river environments revealed physiological profiles predictive of successful migration and spawning. We identified a common genomic profile that was correlated with survival in each study. In ocean-tagged fish, a mortality-related genomic signature was associated with a 13.5-fold greater chance of dying en route. In river-tagged fish, the same genomic signature was associated with a 50% increase in mortality before reaching the spawning grounds in one of three stocks tested. At the spawning grounds, the same signature was associated with 3.7-fold greater odds of dying without spawning. Functional analysis raises the possibility that the mortality-related signature reflects a viral infection.     

Geographic variability and anti-staphylococcal activity of the chrysophaentins and their synthetic fragments

Drug-resistant Staphylococcus aureus is a continuing public health concern, both in the hospital and community settings. Antibacterial compounds that possess novel structural scaffolds and are effective against multiple S. aureus strains, including current drug-resistant ones, are needed. Previously, we have described the chrysophaentins, a family of bisdiarylbutene macrocycles from the chrysophyte alga Chrysophaeum taylori that inhibit the growth of S. aureus and methicillin-resistant S. aureus (MRSA). In this study we have analyzed the geographic variability of chrysophaentin production in C. taylori located at different sites on the island of St. John, U.S. Virgin Islands, and identified two new linear chrysophaentin analogs, E2 and E3. In addition, we have expanded the structure activity relationship through synthesis of fragments comprising conserved portions of the chrysophaentins, and determined the antimicrobial activity of natural chrysophaentins and their synthetic analogs against five diverse S. aureus strains. We find that the chrysophaentins show similar activity against all S. aureus strains, regardless of their drug sensitivity profiles. The synthetic chrysophaentin fragments indeed mimic the natural compounds in their spectrum of antibacterial activity, and therefore represent logical starting points for future medicinal chemistry studies of the natural products and their analogs.     

Effects of weather, fuel and terrain on fire severity in topographically diverse landscapes of south-eastern Australia

The effects of weather, terrain, fuels on fire severity were compared using remote sensing of the severity of two large fires in south-eastern Australian forests. The probability of contrasting levels of fire severity (fire confined to the understorey vs. tree canopies consumed) was analysed using logistic regression. These severities equate to extremes of fire intensity (<1,500 vs. >10,000 kW m^?1), consequent suppression potential (high vs. nil) and potential adverse ecological impacts on vertebrate fauna and soils (low vs. high). Weather was the major influence on fire severity. Crown fire was absent under non-extreme weather and but more likely under extreme weather, particularly on ridges in vegetation unburnt for >10 years. Crown fire probability was very low in recently burnt vegetation (1–5 years) and increased at higher fuel ages. In all cases, fire severity was lower in valleys, probably due to effects of wind protection and higher fuel moisture in moderating fire behaviour. Under non-extreme weather, fires are likely to be suppressible and burn heterogeneously, due to the influence of topographic position, slope and fuel load. Under extreme weather, fires are influenced only by fuel and topographic position, and probability of suppression on accessible ridges will be low except in recently burnt (i.e. 1–5 year old) fuels. Topographically imposed variation may mitigate adverse ecological effects on arboreal fauna and soil erosion potential.     

Tomato can be a latent carrier of ‘Candidatus Liberibacter solanacearum’, the causal agent of potato zebra chip disease

‘Candidatus Liberibacter solanacearum’ was recently described as the causal agent of potato zebra chip disease. This pathogen occurs in North America, New Zealand, and Northern Europe on various crops, and may spread to other potato growing regions. Observation on ‘Ca. L. solanacearum’‐infected tomato and potato plants propagated in growth chambers over 5 years indicated that tomato plants (cvs Moneymaker and Roma) can be a latent carrier of ‘Ca. L. solanacearum’. Tomato plants graft‐inoculated with scions from latently infected tomato plants remained symptomless, but tested positive in a species specific PCR assay. ‘Ca. L. solanacearum’ was consistently detected in the top, middle and bottom portion of the symptomless tomato plants, including stem, petiole, midrib, vein, flowers and fruits. In tomato fruits, ‘Ca. L. solanacearum’ was evenly distributed in the tissues at the peduncle and style ends, as well as in the pericarp, and columella placenta tissues. This is the first report that ‘Ca. L. solanacearum’ is present in a plant reproductive organ. In contrast, potato plants (cvs. Jemseg, Atlantic, Shepody, Frontier Russet, Russet Burbank, Red Pontiac, and Russet Norkotah) grafted with scions from the same latently infected tomato plants resulted in typical symptoms of purple top, leaf scorch, and other disease symptoms in plants and brown discoloration in the vascular ring and medullary rays in tubers.     

Comparison of techniques for correlating survival and gene expression data from wild salmon

Abstract – In laboratory and field studies of survival, one of two alternative analytical techniques is often used to estimate survival rates and identify covariates, namely parametric survival analysis or Cormack–Jolly–Seber models. These techniques differ in algorithms and assumptions of the data. They also tend to be used under different circumstances depending on whether the intention is to demonstrate group‐specific differences or to predict survival variables. Here, we apply and compare both analytical techniques in a study that couples functional genomics with biotelemetry to ascertain the role of physiological condition on survival of adult sockeye salmon (Oncorhynchus nerka) migrating in the Fraser River, British Columbia, which builds on the growing concern over the decline in numbers of spawning fish. Herein, we show a high level of quantitative and qualitative agreement between the two analytical methods, with both showing a strong relationship exists between the genomic signature that accounts for the largest source of variance in gene expression among individuals and survival in one of the three populations assessed. This high level of agreement suggests the data and the approaches are generating reliable results. The novel approach used in our study to identify physiological processes associated with reduced fitness in wild populations should be of broad interest to conservation biologists and resource managers as it may help reduce the uncertainty associated with predicting population sizes.     

Strategies for the capture and transport of bonefish, Albula vulpes, from tidal creeks to a marine research laboratory for long-term holding

Throughout their circumtropical distribution, bonefish ( Albula spp.) play a vital role in local economies as a highly prized sport fish. Recent interest in stock enhancement to sustain bonefish fisheries has led to the recognition that there currently are no data on how to live capture large numbers of adults (potential broodstock), transport them to captive facilities and how to handle them to ensure high survival. The objective of this study was to develop strategies for the capture and relocation of wild bonefish to a marine research holding facility to enable basic research and explore the potential for culturing bonefish for stock enhancement. Bonefish Albula vulpes (Linnaeus, 1758) were captured as they entered or left tidal creeks on Eleuthera, The Bahamas using seine nets and then transported by boat or truck to the laboratory. The relocation process evoked secondary stress responses at the metabolic, osmoregulatory and haematological levels as indicated by changes in blood glucose, lactate, haematocrit and ion values, relative to control fish. Physical and behavioural disturbances were also observed in bonefish that were unable to acclimate to laboratory conditions. Successful laboratory acclimation and long-term holding of wild bonefish was achieved through an adaptive learning process, whereby we identified a series of strategies and handling techniques to facilitate the acclimation of wild adult bonefish to captivity. This knowledge will enable future laboratory research on bonefish and is a prerequisite to the culture of this highly prized sport fish, and other sub-tropical and tropical marine species.     

Posttranslational glutamylation of alpha-tubulin

The high degree of tubulin heterogeneity in neurons is controlled mainly at the posttranslational level. Several variants of alpha-tubulin can be posttranslationally labeled after incubation of cells with [3H]acetate or [3H]glutamate. Peptides carrying the radioactive moiety were purified by high-performance liquid chromatography. Amino acid analysis, Edman degradation sequencing, and mass spectrometric analysis of these peptides led to the characterization of a posttranslational modification consisting of the successive addition of glutamyl units on the gamma-carboxyl group of a glutamate residue (Glu445). This modification, localized within a region of alpha-tubulin that is important in the interactions of tubulin with microtubule-associated proteins and calcium, could play a role in regulating microtubule dynamics.     

Tubulin polyglutamylase enzymes are members of the TTL domain protein family

Polyglutamylation of tubulin has been implicated in several functions of microtubules, but the identification of the responsible enzyme(s) has been challenging. We found that the neuronal tubulin polyglutamylase is a protein complex containing a tubulin tyrosine ligase-like (TTLL) protein, TTLL1. TTLL1 is a member of a large family of proteins with a TTL homology domain, whose members could catalyze ligations of diverse amino acids to tubulins or other substrates. In the model protist Tetrahymena thermophila, two conserved types of polyglutamylases were characterized that differ in substrate preference and subcellular localization.