Interaction of the La-related protein Slf1 with colliding ribosomes maintains translation of oxidative-stress responsive mRNAs.

In response to oxidative stress cells reprogram gene expression to enhance levels of antioxidant enzymes and promote survival. In Saccharomyces cerevisiae the polysome-interacting La-related proteins (LARPs) Slf1 and Sro9 aid adaptation of protein synthesis during stress by undetermined means. To gain insight in their mechanisms of action in stress responses, we determined LARP mRNA binding positions in stressed and unstressed cells. Both proteins bind within coding regions of stress-regulated antioxidant enzyme and other highly translated mRNAs in both optimal and stressed conditions. LARP interaction sites are framed and enriched with ribosome footprints suggesting ribosome-LARP-mRNA complexes are identified. Although stress-induced translation of antioxidant enzyme mRNAs is attenuated in slf1Δ, these mRNAs remain on polysomes. Focusing further on Slf1, we find it binds to both monosomes and disomes following RNase treatment. slf1Δ reduces disome enrichment during stress and alters programmed ribosome frameshifting rates. We propose that Slf1 is a ribosome-associated translational modulator that stabilises stalled/collided ribosomes, prevents ribosome frameshifting and so promotes translation of a set of highly-translated mRNAs that together facilitate cell survival and adaptation to stress.

Using Fluorescence Recovery After Photobleaching data to uncover filament dynamics.

Fluorescence Recovery After Photobleaching (FRAP) has been extensively used to understand molecular dynamics in cells. This technique when applied to soluble, globular molecules driven by diffusion is easily interpreted and well understood. However, the classical methods of analysis cannot be applied to anisotropic structures subjected to directed transport, such as cytoskeletal filaments or elongated organelles transported along microtubule tracks. A new mathematical approach is needed to analyze FRAP data in this context and determine what information can be obtain from such experiments. To address these questions, we analyze fluorescence intensity profile curves after photobleaching of fluorescently labelled intermediate filaments anterogradely transported along microtubules. We apply the analysis to intermediate filament data to determine information about the filament motion. Our analysis consists of deriving equations for fluorescence intensity profiles and developing a mathematical model for the motion of filaments and simulating the model. Two closed forms for profile curves were derived, one for filaments of constant length and one for filaments with constant velocity, and three types of simulation were carried out. In the first type of simulation, the filaments have random velocities which are constant for the duration of the simulation. In the second type, filaments have random velocities which instantaneously change at random times. In the third type, filaments have random velocities and exhibit pausing between velocity changes. Our analysis shows: the most important distribution governing the shape of the intensity profile curves obtained from filaments is the distribution of the filament velocity. Furthermore, filament length which is constant during the experiment, had little impact on intensity profile curves. Finally, gamma distributions for the filament velocity with pauses give the best fit to asymmetric fluorescence intensity profiles of intermediate filaments observed in FRAP experiments performed in polarized migrating astrocytes. Our analysis also shows that the majority of filaments are stationary. Overall, our data give new insight into the regulation of intermediate filament dynamics during cell migration.

Drug extravasation with Enfortumab vedotin.

INTRODUCTION: Enfortumab vedotin is an antibody drug conjugate approved for management of pretreated locally advanced or metastatic urothelial carcinoma, which is associated with a rare risk of drug extravasation and soft tissue reactions. CASE REPORT: We report two cases of EV extravasation with subsequent development of bullae and cellulitis. MANAGEMENT AND OUTCOME: They were both treated for cellulitis and had conservative management without surgical intervention and were able to resume treatment with Enfortumab vedotin without subsequent adverse events. DISCUSSION: We propose that EV acts as a vesicant upon extravasation, highlight measures to prevent extravasation events, and encourage appropriate measures when dealing such as attempt of aspiration, removal of catheter, application of compresses, and thorough documentation with photographic evidence.

Drug-Induced Thrombocytopenia Due to Nintedanib during Treatment of Idiopathic Pulmonary Fibrosis.

Nintedanib is a tyrosine kinase inhibitor that was approved for the treatment of patients with idiopathic pulmonary fibrosis in 2014. The most common side effect of Nintedanib is diarrhea, and thrombocytopenia is a rare side effect of Nintedanib. The exact mechanism is unknown, and the literature lacks case reports of this phenomenon. Here, we report the case of a patient who developed thrombocytopenia 12 weeks after starting treatment with Nintedanib. The patient underwent an extensive work up for infectious, hematological, autoimmune, and neoplastic diseases. The patient's thrombocytopenia resolved following cessation of Nintedanib. This case is significant as it reports a rare side effect that might have detrimental consequences if not recognized and treated timely. Additionally, the onset of thrombocytopenia was delayed, 3 months after the initiation of Nintedanib. We also highlight the various literature regarding drug-induced thrombocytopenia and explore the necessary work-up needed to exclude other potential diagnoses. We hope to advocate for multidisciplinary teams to be aware of patients with pulmonary fibrosis on Nintedanib so that this adverse effect can be recognized promptly.

Understanding the role of dopamine in cancer: past, present and future.

Dopamine (DA, 3-hydroxytyramine) is a member of the catecholamine family and is classically characterized according to its role in the central nervous system as a neurotransmitter. In recent decades, many novel and intriguing discoveries have been made about the peripheral expression of DA receptors (DRs) and the role of DA signaling in both normal and pathological processes. Drawing from decades of evidence suggesting a link between DA and cancer, the DA pathway has recently emerged as a potential target in antitumor therapies. Due to the onerous, expensive and frequently unsuccessful nature of drug development, the repurposing of dopaminergic drugs for cancer therapy has the potential to greatly benefit patients and drug developers alike. However, the lack of clear mechanistic data supporting the direct involvement of DRs and their downstream signaling components in cancer represents an ongoing challenge that has limited the translation of these drugs to the clinic. Despite this, the breadth of evidence linking DA to cancer and non-tumor cells in the tumor microenvironment justifies further inquiry into the potential applications of this treatment modality in cancer. Herein, we review the literature characterizing the interplay between the DA signaling axis and cancer, highlighting key findings, and then propose rational lines of investigation to follow.

Common carotid artery responses to the cold-pressor test are impaired in individuals with cervical spinal cord injury.

Cervical spinal cord injury (SCI) leads to autonomic cardiovascular dysfunction that underlies the three- to fourfold elevated risk of cardiovascular disease in this population. Reduced common carotid artery (CCA) dilatory responsiveness during the cold-pressor test (CPT) is associated with greater cardiovascular disease risk and progression. The cardiovascular and CCA responses to the CPT may provide insight into cardiovascular autonomic dysfunction and cardiovascular disease risk in individuals with cervical SCI. Here, we used CPT to perturb the autonomic nervous system in 14 individuals with cervical SCI and 12 uninjured controls, while measuring cardiovascular responses and CCA diameter. The CCA diameter responses were 55% impaired in those with SCI compared with uninjured controls (P = 0.019). The CCA flow, velocity, and shear response to CPT were reduced in SCI by 100% (P < 0.001), 113% (P = 0.001), and 125% (P = 0.002), respectively. The association between mean arterial pressure and CCA dilation observed in uninjured individuals (r = 0.54, P = 0.004) was absent in the SCI group (r = 0.22, P = 0.217). Steady-state systolic blood pressure (P = 0.020), heart rate (P = 0.003), and cardiac contractility (P < 0.001) were reduced in those with cervical SCI, whereas total peripheral resistance was increased compared with uninjured controls (P = 0.042). Relative cerebral blood velocity responses to CPT were increased in the SCI group and reduced in controls (middle cerebral artery, P = 0.010; posterior cerebral artery, P = 0.026). The CCA and cardiovascular responsiveness to CPT are impaired in those with cervical SCI.NEW & NOTEWORTHY This is the first study demonstrating that CCA responses during CPT are suppressed in SCI. Specifically, CCA diameter, flow, velocity, and shear rate were reduced. The relationship between changes in MAP and CCA dilatation in response to CPT was absent in individuals with SCI, despite similar cardiovascular activation between SCI and uninjured controls. These findings support the notion of elevated cardiovascular disease risk in SCI and that the cardiovascular responses to environmental stimuli are impaired.

Potential biomarkers of endocrine and habitat disruption identified via RNA-Seq in Salvelinus fontinalis with proximity to fracking operations in Pennsylvania headwater stream ecosystems.

Unconventional natural gas development (fracking) has been a rapidly expanding technique used for the extraction of natural gas from the Marcellus Shale formation in Pennsylvania. There remains a knowledge gap regarding the ecological impacts of fracking, especially regarding the long-term health of native Brook trout (Salvelinus fontinalis) populations. During the summer of 2015, Brook trout were sampled from twelve streams located in forested, northwestern Pennsylvania in order to evaluate the impacts of fracking on Brook trout. Four stream sites were undisturbed (no fracking activity), three had a developed well pad without fracking activity, and five had active fracking with natural gas production. Liver tissue was isolated from two to five fish per stream and underwent RNA-Seq analysis to identify differentially expressed genes between ecosystems with differing fracking status. Data were analyzed individually and with samples pooled within-stream to account for hierarchical data structure and variation in sample coverage within streams. Differentially expressed and differentially alternatively spliced genes had functions related to lipid and steroid metabolism, mRNA processing, RNA polymerase and protein regulation. Unique to our study, genes related to xenobiotic and stress responses were found as well as potential markers for endocrine disruption and saline adaptation that were identified in watersheds with active fracking activity. These results support the utility of RNA-Seq to assess trout health and suggest detrimental impacts of fracking on sensitive trout populations.

Development of priorities for a Canadian strategy to advance activity-based therapies after spinal cord injury.

STUDY DESIGN: Participatory design. OBJECTIVES: Activity-based therapies (ABT) have physical and psychosocial benefits for individuals with spinal cord injury (SCI). A Canadian ABT summit was held to: (1) identify methods used in stroke rehabilitation that may be appropriate for SCI; (2) understand the current state of ABT activities in Canada; and (3) identify priorities for ABT research and care for the next five years. SETTING: Stakeholder-engaged meeting at a tertiary rehabilitation hospital. METHODS: Thirty-nine stakeholders, including individuals with SCI, frontline clinicians, healthcare administrators, researchers, funders and health policy experts, attended. Two participants were note-takers. Priority identification occurred through input from stakeholder groups, followed by individual voting. Conventional content analysis was used to synthesize the information in the meeting notes. RESULTS: The strengths of ABT in stroke rehabilitation included clear and clinically feasible definitions, measurements and interventions, and recognized requirements for implementation (e.g. behavior change, partnerships). Knowledge gaps concerning ABT activities in Canada were identified for acute and community settings, non-traumatic populations, and the interventions, equipment and standardized measures (i.e. upper limb, activity levels) used. Five priorities for ABT across the continuum of care were identified: (1) Identify current ABT activities; (2) Create a network to facilitate dialog; (3) Track engagement in ABT activities; (4) Develop and implement best practice recommendations; and (5) Study optimal timing, methods, and dose of ABT. Working groups were formed to address priorities 1-3. CONCLUSIONS: The priorities will guide SCI research and care activities in Canada over the next five years. SPONSORSHIP: Praxis Spinal Cord Institute.

Factors associated with intensive care admission in patients with lung cancer: a population-based observational study of 26, 731 patients.

BACKGROUND: Lung cancer is the most common cause of cancer related death worldwide and survival is poor. Patients with lung cancer may develop a critical illness, but it is unclear what features are associated with an Intensive Care Unit (ICU) admission. METHODS: This retrospective, observational, population-based study of linked cancer registration, ICU, hospital discharge and mortality data described the factors associated with ICU admission in patients with lung cancer. The cohort comprised all incident cases of adult lung cancer diagnosed between 1st January 2000 and 31st December 2009 in the West of Scotland, UK, who were subsequently admitted to an ICU within 2 years of cancer diagnosis. Multiple logistic regression was used to determine factors associated with admission. RESULTS: 26,731 incident cases of lung cancer were diagnosed with 398 (1.5%) patients admitted to an ICU. Patients were most commonly admitted with respiratory conditions and there was a high rate of invasive mechanical ventilation. ICU, in-hospital and six-month survival were 58.5, 42.0 and 31.2%, respectively. Surgical treatment of lung cancer increased the odds of ICU admission (OR 7.23 (5.14-10.2)). Odds of admission to ICU were reduced with older age (75-80 years OR 0.69 (0.49-0.94), > 80 years OR 0.21 (0.12-0.37)), female gender (OR 0.73 (0.59-0.90)) and radiotherapy (OR 0.54 (0.39-0.73)) or chemotherapy treatment (OR 0.52 (0.38-0.70)). CONCLUSION: 1.5% of patients diagnosed with lung cancer are admitted to an ICU but both short term and long term survival was poor. Factors associated with ICU admission included age < 75 years, male gender and surgical treatment of cancer.

Surface Water Microbial Community Response to the Biocide 2,2-Dibromo-3-Nitrilopropionamide, Used in Unconventional Oil and Gas Extraction.

Production of unconventional oil and gas continues to rise, but the effects of high-density hydraulic fracturing (HF) activity near aquatic ecosystems are not fully understood. A commonly used biocide in HF, 2,2-dibromo-3-nitrilopropionamide (DBNPA), was studied in microcosms of HF-impacted (HF+) versus HF-unimpacted (HF-) surface water streams to (i) compare the microbial community response, (ii) investigate DBNPA degradation products based on past HF exposure, and (iii) compare the microbial community response differences and similarities between the HF biocides DBNPA and glutaraldehyde. The microbial community responded to DBNPA differently in HF-impacted versus HF-unimpacted microcosms in terms of the number of 16S rRNA gene copies quantified, alpha and beta diversity, and differential abundance analyses of microbial community composition through time. The differences in microbial community changes affected degradation dynamics. HF-impacted microbial communities were more sensitive to DBNPA, causing the biocide and by-products of the degradation to persist for longer than in HF-unimpacted microcosms. A total of 17 DBNPA by-products were detected, many of them not widely known as DBNPA by-products. Many of the brominated by-products detected that are believed to be uncharacterized may pose environmental and health impacts. Similar taxa were able to tolerate glutaraldehyde and DBNPA; however, DBNPA was not as effective for microbial control, as indicated by a smaller overall decrease of 16S rRNA gene copies/ml after exposure to the biocide, and a more diverse set of taxa was able to tolerate it. These findings suggest that past HF activity in streams can affect the microbial community response to environmental perturbation such as that caused by the biocide DBNPA.IMPORTANCE Unconventional oil and gas activity can affect pH, total organic carbon, and microbial communities in surface water, altering their ability to respond to new environmental and/or anthropogenic perturbations. These findings demonstrate that 2,2-dibromo-3-nitrilopropionamide (DBNPA), a common hydraulic fracturing (HF) biocide, affects microbial communities differently as a consequence of past HF exposure, persisting longer in HF-impacted (HF+) waters. These findings also demonstrate that DBNPA has low efficacy in environmental microbial communities regardless of HF impact. These findings are of interest, as understanding microbial responses is key for formulating remediation strategies in unconventional oil and gas (UOG)-impacted environments. Moreover, some DBNPA degradation by-products are even more toxic and recalcitrant than DBNPA itself, and this work identifies novel brominated degradation by-products formed.

Exercise interventions and their effect on masculinity, body image, and personal identity in prostate cancer-A systematic qualitative review.

OBJECTIVE: Men with prostate cancer face various body composition and psychosocial challenges following diagnosis. Movement-based interventions such as exercise may represent novel strategies to improve these important biopsychosocial changes. This systematic qualitative review aimed to examine the various exercise interventions and their effect on male perception of masculinity, body image, and personal identity. METHODS: A systematic search across nine electronic databases was conducted in July 2017 and repeated in August 2018. Eligible studies included qualitative works examining masculinity, body image, or personal identity within an exercise intervention. Thematic content analysis allowed for qualitative synthesis across numerous studies. RESULTS: Six studies met eligibility criteria for inclusion. Four interventions used multimodal aerobic and resistance training, one incorporated aerobic exercise through football practice, and one utilized a home-based aerobic plus yoga program. Exercise was implicated to improve masculinity through creation of a safe community, allowed for refocusing on valued male traits, provided a source of distraction, and offered a means of establishing control over one's illness. Exercise also facilitated a process of self-reflection secondary to changes in physique and helped to re-establish male self-efficacy. CONCLUSIONS: Regardless of prostate cancer stage, treatment status, or prior androgen deprivation therapy exposure, both aerobic or aerobic and resistance training exerted positive effects on perceived feelings of masculinity, body image, and personal identity.

Impacts of Glutaraldehyde on Microbial Community Structure and Degradation Potential in Streams Impacted by Hydraulic Fracturing.

The environmental impacts of hydraulic fracturing, particularly those of surface spills in aquatic ecosystems, are not fully understood. The goals of this study were to (1) understand the effect of previous exposure to hydraulic fracturing fluids on aquatic microbial community structure and (2) examine the impacts exposure has on biodegradation potential of the biocide glutaraldehyde. Microcosms were constructed from hydraulic fracturing-impacted and nonhydraulic fracturing-impacted streamwater within the Marcellus shale region in Pennsylvania. Microcosms were amended with glutaraldehyde and incubated aerobically for 56 days. Microbial community adaptation to glutaraldehyde was monitored using 16S rRNA gene amplicon sequencing and quantification by qPCR. Abiotic and biotic glutaraldehyde degradation was measured using ultra-performance liquid chromatography--high resolution mass spectrometry and total organic carbon. It was found that nonhydraulic fracturing-impacted microcosms biodegraded glutaraldehyde faster than the hydraulic fracturing-impacted microcosms, showing a decrease in degradation potential after exposure to hydraulic fracturing activity. Hydraulic fracturing-impacted microcosms showed higher richness after glutaraldehyde exposure compared to unimpacted streams, indicating an increased tolerance to glutaraldehyde in hydraulic fracturing impacted streams. Beta diversity and differential abundance analysis of sequence count data showed different bacterial enrichment for hydraulic fracturing-impacted and nonhydraulic fracturing-impacted microcosms after glutaraldehyde addition. These findings demonstrated a lasting effect on microbial community structure and glutaraldehyde degradation potential in streams impacted by hydraulic fracturing operations.

Perceptions of masculinity and body image in men with prostate cancer: the role of exercise.

PURPOSE: The goal of this study was to explore the association between levels of exercise and patterns of masculinity, body image, and quality of life in men undergoing diverse treatment protocols for prostate cancer. METHODS: Fifty men with prostate cancer (aged 42-86) completed self-report measures. Self-reported measures included the following: the Godin Leisure Time Exercise Questionnaire (GLTEQ), Masculine Self-esteem Scale (MSES), Personal Attributes Questionnaire (PAQ), Body Image Scale (BIS), and the Functional Assessment of Cancer Therapy-Prostate (FACT-P). Masculinity, body image, and quality of life scores were compared between men obtaining recommended levels of exercise (aerobic or resistance) and those not obtaining recommended level of exercise. Secondary outcomes included the association between masculinity, body image, and quality of life scores as they relate to exercise levels. RESULTS: There were significantly higher scores of masculinity (p < 0.01), physical well-being (p < 0.05), prostate cancer specific well-being (p < 0.05), and overall quality of life (p < 0.05) in those obtaining at least 150 min of moderate to vigorous aerobic exercise. In the 48% of men who had never received androgen deprivation therapy, significantly higher levels of masculinity, body image, and quality of life were observed in those meeting aerobic guidelines. CONCLUSIONS: Whether treatment includes androgen deprivation or not, men who participate in higher levels of aerobic exercises report higher levels of masculinity, improved body image, and quality of life than those who are inactive. Future longitudinal research is required evaluating exercise level and its effect on masculinity and body image.

Direct and Absolute Quantification of over 1800 Yeast Proteins via Selected Reaction Monitoring.

Defining intracellular protein concentration is critical in molecular systems biology. Although strategies for determining relative protein changes are available, defining robust absolute values in copies per cell has proven significantly more challenging. Here we present a reference data set quantifying over 1800Saccharomyces cerevisiaeproteins by direct means using protein-specific stable-isotope labeled internal standards and selected reaction monitoring (SRM) mass spectrometry, far exceeding any previous study. This was achieved by careful design of over 100 QconCAT recombinant proteins as standards, defining 1167 proteins in terms of copies per cell and upper limits on a further 668, with robust CVs routinely less than 20%. The selected reaction monitoring-derived proteome is compared with existing quantitative data sets, highlighting the disparities between methodologies. Coupled with a quantification of the transcriptome by RNA-seq taken from the same cells, these data support revised estimates of several fundamental molecular parameters: a total protein count of ∼100 million molecules-per-cell, a median of ∼1000 proteins-per-transcript, and a linear model of protein translation explaining 70% of the variance in translation rate. This work contributes a "gold-standard" reference yeast proteome (including 532 values based on high quality, dual peptide quantification) that can be widely used in systems models and for other comparative studies.

The 4E-BP Caf20p Mediates Both eIF4E-Dependent and Independent Repression of Translation.

Translation initiation factor eIF4E mediates mRNA selection for protein synthesis via the mRNA 5'cap. A family of binding proteins, termed the 4E-BPs, interact with eIF4E to hinder ribosome recruitment. Mechanisms underlying mRNA specificity for 4E-BP control remain poorly understood. Saccharomyces cerevisiae 4E-BPs, Caf20p and Eap1p, each regulate an overlapping set of mRNAs. We undertook global approaches to identify protein and RNA partners of both 4E-BPs by immunoprecipitation of tagged proteins combined with mass spectrometry or next-generation sequencing. Unexpectedly, mass spectrometry indicated that the 4E-BPs associate with many ribosomal proteins. 80S ribosome and polysome association was independently confirmed and was not dependent upon interaction with eIF4E, as mutated forms of both Caf20p and Eap1p with disrupted eIF4E-binding motifs retain ribosome interaction. Whole-cell proteomics revealed Caf20p mutations cause both up and down-regulation of proteins and that many changes were independent of the 4E-binding motif. Investigations into Caf20p mRNA targets by immunoprecipitation followed by RNA sequencing revealed a strong association between Caf20p and mRNAs involved in transcription and cell cycle processes, consistent with observed cell cycle phenotypes of mutant strains. A core set of over 500 Caf20p-interacting mRNAs comprised of both eIF4E-dependent (75%) and eIF4E-independent targets (25%), which differ in sequence attributes. eIF4E-independent mRNAs share a 3' UTR motif. Caf20p binds all tested motif-containing 3' UTRs. Caf20p and the 3'UTR combine to influence ERS1 mRNA polysome association consistent with Caf20p contributing to translational control. Finally ERS1 3'UTR confers Caf20-dependent repression of expression to a heterologous reporter gene. Taken together, these data reveal conserved features of eIF4E-dependent Caf20p mRNA targets and uncover a novel eIF4E-independent mode of Caf20p binding to mRNAs that extends the regulatory role of Caf20p in the mRNA-specific repression of protein synthesis beyond its interaction with eIF4E.

A continuous-time model of centrally coordinated motion with random switching.

This paper considers differential problems with random switching, with specific applications to the motion of cells and centrally coordinated motion. Starting with a differential-equation model of cell motion that was proposed previously, we set the relaxation time to zero and consider the simpler model that results. We prove that this model is well-posed, in the sense that it corresponds to a pure jump-type continuous-time Markov process (without explosion). We then describe the model's long-time behavior, first by specifying an attracting steady-state distribution for a projection of the model, then by examining the expected location of the cell center when the initial data is compatible with that steady-state. Under such conditions, we present a formula for the expected velocity and give a rigorous proof of that formula's validity. We conclude the paper with a comparison between these theoretical results and the results of numerical simulations.

Puf3p induces translational repression of genes linked to oxidative stress.

In response to stress, the translation of many mRNAs in yeast can change in a fashion discordant with the general repression of translation. Here, we use machine learning to mine the properties of these mRNAs to determine specific translation control signals. We find a strong association between transcripts acutely translationally repressed under oxidative stress and those associated with the RNA-binding protein Puf3p, a known regulator of cellular mRNAs encoding proteins targeted to mitochondria. Under oxidative stress, a PUF3 deleted strain exhibits more robust growth than wild-type cells and the shift in translation from polysomes to monosomes is attenuated, suggesting puf3Δ cells perceive less stress. In agreement, the ratio of reduced:oxidized glutathione, a major antioxidant and indicator of cellular redox state, is increased in unstressed puf3Δ cells but remains lower under stress. In untreated conditions, Puf3p migrates with polysomes rather than ribosome-free fractions, but this is lost under stress. Finally, reverse transcriptase-polymerase chain reaction (RT-PCR) of Puf3p targets following affinity purification shows Puf3p-mRNA associations are maintained or increased under oxidative stress. Collectively, these results point to Puf3p acting as a translational repressor in a manner exceeding the global translational response, possibly by temporarily limiting synthesis of new mitochondrial proteins as cells adapt to the stress.

Fracked ecology: Response of aquatic trophic structure and mercury biomagnification dynamics in the Marcellus Shale Formation.

Unconventional natural gas development and hydraulic fracturing practices (fracking) are increasing worldwide due to global energy demands. Research has only recently begun to assess fracking impacts to surrounding environments, and very little research is aimed at determining effects on aquatic biodiversity and contaminant biomagnification. Twenty-seven remotely-located streams in Pennsylvania's Marcellus Shale basin were sampled during June and July of 2012 and 2013. At each stream, stream physiochemical properties, trophic biodiversity, and structure and mercury levels were assessed. We used δ15N, δ13C, and methyl mercury to determine whether changes in methyl mercury biomagnification were related to the fracking occurring within the streams' watersheds. While we observed no difference in rates of biomagnificaion related to within-watershed fracking activities, we did observe elevated methyl mercury concentrations that were influenced by decreased stream pH, elevated dissolved stream water Hg values, decreased macroinvertebrate Index for Biotic Integrity scores, and lower Ephemeroptera, Plecoptera, and Trichoptera macroinvertebrate richness at stream sites where fracking had occurred within their watershed. We documented the loss of scrapers from streams with the highest well densities, and no fish or no fish diversity at streams with documented frackwater fluid spills. Our results suggest fracking has the potential to alter aquatic biodiversity and methyl mercury concentrations at the base of food webs.

Quantitative proteomics and network analysis of SSA1 and SSB1 deletion mutants reveals robustness of chaperone HSP70 network in Saccharomyces cerevisiae.

Molecular chaperones play an important role in protein homeostasis and the cellular response to stress. In particular, the HSP70 chaperones in yeast mediate a large volume of protein folding through transient associations with their substrates. This chaperone interaction network can be disturbed by various perturbations, such as environmental stress or a gene deletion. Here, we consider deletions of two major chaperone proteins, SSA1 and SSB1, from the chaperone network in Sacchromyces cerevisiae. We employ a SILAC-based approach to examine changes in global and local protein abundance and rationalise our results via network analysis and graph theoretical approaches. Although the deletions result in an overall increase in intracellular protein content, correlated with an increase in cell size, this is not matched by substantial changes in individual protein concentrations. Despite the phenotypic robustness to deletion of these major hub proteins, it cannot be simply explained by the presence of paralogues. Instead, network analysis and a theoretical consideration of folding workload suggest that the robustness to perturbation is a product of the overall network structure. This highlights how quantitative proteomics and systems modelling can be used to rationalise emergent network properties, and how the HSP70 system can accommodate the loss of major hubs.