Evaluating chemical signatures in a coastal upwelling region to reconstruct water mass associations of settlement-stage rockfishes

Characterizing the behavior of larvae prior to settlement is integral to understanding population dynamics because coastal oceanography may facilitate or limit settlement. Otolith microchemistry can be used to determine patterns of fish movement, although there is a limited understanding of how this tool can be applied in coastal marine systems. Our goal in this study was to evaluate the application of otolith microchemistry to characterize water mass associations of settlement-stage marine fish in a coastal upwelling region using a 3-step approach. First, we characterized seawater chemistry of coastal water mass types across multiple years, finding differences in the chemical signatures of strong upwelling, weak upwelling, and relaxation events. Second, we experimentally determined the effect of temperature on the partitioning of trace elements in otoliths for 2 rockfishes (Sebastes spp.) to find that the effect of temperature on otolith partition coefficients was element-and species-specific. Finally, we compared coeval changes in seawater and otolith chemistry of settlement-stage rockfishes that were exposed to naturally variable conditions over an upwelling-relaxation cycle. We subsequently evaluate whether laser ablation inductively coupled plasma mass spectrometry effectively measures otolith chemistry over ecologically relevant time scales. We discovered that elemental concentrations in otoliths respond rapidly to changes in seawater chemistry and reflect equivalent proportional changes. This study provides evidence that elemental signatures are valuable tools for reconstructing larval histories of marine fish in coastal upwelling regions

Depletion of Kinesin 5B Affects Lysosomal Distribution and Stability and Induces Peri-Nuclear Accumulation of Autophagosomes in Cancer Cells

Background: Enhanced lysosomal trafficking is associated with metastatic cancer. In an attempt to discover cancer relevant lysosomal motor proteins, we compared the lysosomal proteomes from parental MCF-7 breast cancer cells with those from highly invasive MCF-7 cells that express an active form of the ErbB2 (DN-ErbB2). Methodology/Principal Findings: Mass spectrometry analysis identified kinesin heavy chain protein KIF5B as the only microtubule motor associated with the lysosomes in MCF-7 cells, and ectopic DN-ErbB2 enhanced its lysosomal association. KIF5B associated with lysosomes also in HeLa cervix carcinoma cells as analyzed by subcellular fractionation. The depletion of KIF5B triggered peripheral aggregations of lysosomes followed by lysosomal destabilization, and cell death in HeLa cells. Lysosomal exocytosis in response to plasma membrane damage as well as fluid phase endocytosis functioned, however, normally in these cells. Both HeLa and MCF-7 cells appeared to express similar levels of the KIF5B isoform but the death phenotype was weaker in KIF5B-depleted MCF-7 cells. Surprisingly, KIF5B depletion inhibited the rapamycin-induced accumulation of autophagosomes in MCF-7 cells. In KIF5B-depleted cells the autophagosomes formed and accumulated in the close proximity to the Golgi apparatus, whereas in the control cells they appeared uniformly distributed in the cytoplasm. Conclusions/Significance: Our data identify KIF5B as a cancer relevant lysosomal motor protein with additional functions in autophagosome formatio

A population-based study of tumor gene expression and risk of breast cancer death among lymph node-negative patients

INTRODUCTION: The Oncotype DX assay was recently reported to predict risk for distant recurrence among a clinical trial population of tamoxifen-treated patients with lymph node-negative, estrogen receptor (ER)-positive breast cancer. To confirm and extend these findings, we evaluated the performance of this 21-gene assay among node-negative patients from a community hospital setting. METHODS: A case-control study was conducted among 4,964 Kaiser Permanente patients diagnosed with node-negative invasive breast cancer from 1985 to 1994 and not treated with adjuvant chemotherapy. Cases (n = 220) were patients who died from breast cancer. Controls (n = 570) were breast cancer patients who were individually matched to cases with respect to age, race, adjuvant tamoxifen, medical facility and diagnosis year, and were alive at the date of death of their matched case. Using an RT-PCR assay, archived tumor tissues were analyzed for expression levels of 16 cancer-related and five reference genes, and a summary risk score (the Recurrence Score) was calculated for each patient. Conditional logistic regression methods were used to estimate the association between risk of breast cancer death and Recurrence Score. RESULTS: After adjusting for tumor size and grade, the Recurrence Score was associated with risk of breast cancer death in ER-positive, tamoxifen-treated and -untreated patients (P = 0.003 and P = 0.03, respectively). At 10 years, the risks for breast cancer death in ER-positive, tamoxifen-treated patients were 2.8% (95% confidence interval [CI] 1.7–3.9%), 10.7% (95% CI 6.3–14.9%), and 15.5% (95% CI 7.6–22.8%) for those in the low, intermediate and high risk Recurrence Score groups, respectively. They were 6.2% (95% CI 4.5–7.9%), 17.8% (95% CI 11.8–23.3%), and 19.9% (95% CI 14.2–25.2%) for ER-positive patients not treated with tamoxifen. In both the tamoxifen-treated and -untreated groups, approximately 50% of patients had low risk Recurrence Score values. CONCLUSION: In this large, population-based study of lymph node-negative patients not treated with chemotherapy, the Recurrence Score was strongly associated with risk of breast cancer death among ER-positive, tamoxifen-treated and -untreated patients

Tissue Ischemia During Aortic Repair: The Point of View of the Perfusionist

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Evaluating chemical signatures in a coastal upwelling region to reconstruct water mass associations of settlement-stage rockfishes

Characterizing the behavior of larvae prior to settlement is integral to understanding population dynamics because coastal oceanography may facilitate or limit settlement. Otolith microchemistry can be used to determine patterns of fish movement, although there is a limited understanding of how this tool can be applied in coastal marine systems. Our goal in this study was to evaluate the application of otolith microchemistry to characterize water mass associations of settlement-stage marine fish in a coastal upwelling region using a 3-step approach. First, we characterized seawater chemistry of coastal water mass types across multiple years, finding differences in the chemical signatures of strong upwelling, weak upwelling, and relaxation events. Second, we experimentally determined the effect of temperature on the partitioning of trace elements in otoliths for 2 rockfishes (Sebastes spp.) to find that the effect of temperature on otolith partition coefficients was element-and species-specific. Finally, we compared coeval changes in seawater and otolith chemistry of settlement-stage rockfishes that were exposed to naturally variable conditions over an upwelling-relaxation cycle. We subsequently evaluate whether laser ablation inductively coupled plasma mass spectrometry effectively measures otolith chemistry over ecologically relevant time scales. We discovered that elemental concentrations in otoliths respond rapidly to changes in seawater chemistry and reflect equivalent proportional changes. This study provides evidence that elemental signatures are valuable tools for reconstructing larval histories of marine fish in coastal upwelling regions

Optimizing LA-ICP-MS analytical procedures for elemental depth profiling of foraminifera shells

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is becoming a widespread technique for analyzing elemental ratios in foraminiferal calcite. Here we focus on optimizing LA-ICP-MS for high-resolution depth profiling of elemental ratios through shell walls. This application reveals intrashell variability and provides a unique opportunity to quantify trace element incorporation over short time scales of calcification by an individual foraminifer. High-resolution depth profiling requires careful consideration of both ablation and analytical conditions required to resolve differences in shell chemistry across sub-micron shell thickness. We present laser ablation profiles of NIST SRM 610 standard glass data (in cps) and elemental/Ca ratios (in mmol/mol) from foraminiferal calcite obtained over a range of operating conditions using a Photon Machines 193nm UV excimer laser-ablation system, equipped with a dual-volume ANU HelEx chamber, coupled to an Agilent 7700x quadrupole ICP-MS. Different combinations of energy density, repetition rate, and mass spectrometer cycle time can yield varying elemental profiles. This variability can mimic and/or mask real intrashell trace element heterogeneity in foraminifer shells. At low (<3Hz) laser repetition rates, real intrashell element variation can be obscured depending on the laser energy, whereas using moderate (≥3Hz) laser repetition rates and/or a signal-smoothing device improves the accuracy and precision of intrashell trace element profiles. Shell material is ablated rapidly when using a 5Hz or greater repetition rate and an energy density of 3J/cm2 or greater, resulting in reduced spatial resolution

Relationships Between Temperature, pH, and Crusting on Mg/Ca Ratios in Laboratory-Grown Neogloboquadrina Foraminifera

Mg/Ca ratio paleothermometry in foraminifera is an important tool for the reconstruction and interpretation of past environments. However, existing Mg/Ca:temperature relationships for planktic species inhabiting middle- and high-latitude environments are limited by a lack of information about the development and impact of low-Mg/Ca ratio “crusts” and the influence of the carbonate system on Mg/Ca ratios in these groups. To address this, we cultured individual specimens of Neogloboquadrina incompta and Neogloboquadrina pachyderma in seawater across a range of temperature (6°–12°C) and pH (7.4–8.2). We found by laser ablation inductively couple mass spectrometry analyses of shells that culture-grown crust calcite in N. incompta had a lower Mg/Ca ratio than ontogenetic calcite formed at the same temperature, suggesting that temperature is not responsible for the low-Mg/Ca ratio of neogloboquadrinid crusts. The Mg/Ca:temperature relationship for ontogenetic calcite in N. incompta was consistent with the previously published culture-based relationship, and no significant relationship was found between Mg/Ca ratios and pH in this species. However, the Mg/Ca ratio in laboratory-cultured N. pachyderma was much higher than that reported in previous core top and sediment trap samples, due to lack of crust formation in culture. Application of our ontogenetic calcite-specific Mg/Ca:temperature relationships to fossil N. pachyderma and N. incompta from five intervals in cores from the Santa Barbara Basin and the Bering Sea shows that excluding crust calcite in fossil specimens may improve Mg/Ca-based temperature estimates

Relationships Between Temperature, pH, and Crusting on Mg/Ca Ratios in Laboratory-Grown Neogloboquadrina Foraminifera

Mg/Ca ratio paleothermometry in foraminifera is an important tool for the reconstruction and interpretation of past environments. However, existing Mg/Ca:temperature relationships for planktic species inhabiting middle- and high-latitude environments are limited by a lack of information about the development and impact of low-Mg/Ca ratio “crusts” and the influence of the carbonate system on Mg/Ca ratios in these groups. To address this, we cultured individual specimens of Neogloboquadrina incompta and Neogloboquadrina pachyderma in seawater across a range of temperature (6°–12°C) and pH (7.4–8.2). We found by laser ablation inductively couple mass spectrometry analyses of shells that culture-grown crust calcite in N. incompta had a lower Mg/Ca ratio than ontogenetic calcite formed at the same temperature, suggesting that temperature is not responsible for the low-Mg/Ca ratio of neogloboquadrinid crusts. The Mg/Ca:temperature relationship for ontogenetic calcite in N. incompta was consistent with the previously published culture-based relationship, and no significant relationship was found between Mg/Ca ratios and pH in this species. However, the Mg/Ca ratio in laboratory-cultured N. pachyderma was much higher than that reported in previous core top and sediment trap samples, due to lack of crust formation in culture. Application of our ontogenetic calcite-specific Mg/Ca:temperature relationships to fossil N. pachyderma and N. incompta from five intervals in cores from the Santa Barbara Basin and the Bering Sea shows that excluding crust calcite in fossil specimens may improve Mg/Ca-based temperature estimates

Environmental controls on the geochemistry of Globorotalia truncatulinoides in the Gulf of Mexico: Implications for paleoceanographic reconstructions

Modern observations of planktic foraminifera from sediment trap studies help to constrain the regional ecology of paleoceanographically valuable species. Results from a weekly-resolved sediment trap time series (2008–2014) in the northern Gulf of Mexico demonstrate that 92% of Globorotalia truncatulinoides flux occurs in winter (January, February, and March), and that encrusted and non-encrusted individuals represent calcification in distinct depth habitats. We use individual foraminiferal analysis (IFA) of G. truncatulinoides tests to investigate differences in the elemental (Mg/Ca) and isotopic composition (δ18O and δ13C) of the encrusted and non-encrusted ontogenetic forms of G. truncatulinoides, and to estimate their calcification depth in the northern Gulf of Mexico. We estimate that non-encrusted and encrusted G. truncatulinoides have mean calcification depths of 66 ± 9 m and 379 ± 76 m, respectively. We validate the Mg/Ca-calcification temperature relationship for G. truncatulinoides and demonstrate that the δ18O and Mg/Ca of the non-encrusted form is a suitable proxy for winter surface mixed layer conditions in the Gulf of Mexico. Care should be taken not to combine encrusted and non-encrusted individuals of G. truncatulinoides for down core paleoceanographic studies