Diversity of microbial eukaryotes along the West Antarctic Peninsula in austral spring

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Grattepanche, J.-D., Jeffrey, W., Gast, R., & Sanders, R. Diversity of microbial eukaryotes along the West Antarctic Peninsula in austral spring. Frontiers in Microbiology, 13, (2022): 844856, https://doi.org/10.3389/fmicb.2022.844856.During a cruise from October to November 2019, along the West Antarctic Peninsula, between 64.32 and 68.37°S, we assessed the diversity and composition of the active microbial eukaryotic community within three size fractions: micro- (> 20 μm), nano- (20–5 μm), and pico-size fractions (5–0.2 μm). The communities and the environmental parameters displayed latitudinal gradients, and we observed a strong similarity in the microbial eukaryotic communities as well as the environmental parameters between the sub-surface and the deep chlorophyll maximum (DCM) depths. Chlorophyll concentrations were low, and the mixed layer was shallow for most of the 17 stations sampled. The richness of the microplankton was higher in Marguerite Bay (our southernmost stations), compared to more northern stations, while the diversity for the nano- and pico-plankton was relatively stable across latitude. The microplankton communities were dominated by autotrophs, mostly diatoms, while mixotrophs (phototrophs-consuming bacteria and kleptoplastidic ciliates, mostly alveolates, and cryptophytes) were the most abundant and active members of the nano- and picoplankton communities. While phototrophy was the dominant trophic mode, heterotrophy (mixotrophy, phagotrophy, and parasitism) tended to increase southward. The samples from Marguerite Bay showed a distinct community with a high diversity of nanoplankton predators, including spirotrich ciliates, and dinoflagellates, while cryptophytes were observed elsewhere. Some lineages were significantly related—either positively or negatively—to ice coverage (e.g., positive for Pelagophyceae, negative for Spirotrichea) and temperature (e.g., positive for Cryptophyceae, negative for Spirotrichea). This suggests that climate changes will have a strong impact on the microbial eukaryotic community.This work was supported by the National Science Foundation (Grant Nos. ANT 1744767 to RS, ANT 1744663 to RG, and ANT 1744638 to WJ). This research was based, in part, upon sequencing conducted using the Rhode Island Genomics and Sequencing Center, which was supported in part by the National Science Foundation (MRI Grant No. DBI-0215393 and EPSCoR Grant Nos. 0554548 and EPS-1004057), the US Department of Agriculture (Grant Nos. 2002-34438-12688 and 2003-34438-13111), and the University of Rhode Island. This research includes calculations carried out on Temple University HPC resources supported in part by the National Science Foundation through major research instrumentation (Grant No. 1625061) and by the US Army Research Laboratory under (Contract No. W911NF-16-2-0189)

Ciliate microzooplankton from the Northeastern Gulf of Mexico

Microzooplankton mediate a critical juncture of autotrophic and heterotrophic microbial production in the water column. Taxonomic and ecological work on this group has been substantial, yet few reports exist for the offshore waters of the Gulf of Mexico (GOM). This report focuses on protists in the phylum Ciliophora collected at stations spanning the continental shelf in the northeastern GOM. We hypothesized that patterns of spatial distribution across the region would be west–east along the coast, rather than north–south coastal to offshore, reflecting major freshwater sources. Samples were obtained by 10 µm plankton net for microscopy and by filtration of seawater for DNA extraction and ciliate-specific clone sequencing. Microscopy and molecular analysis recovered 46 and 156 taxa, respectively. Some visually identified taxa were missing from the sequence analysis and sequences from unknown species dominated molecular results. Differences were apparent with both dominant and rare taxa between February and July sampling and across a trophic gradient from coastal influenced stations to those more representative of the offshore environment. This report provides new data on ciliate microzooplankton richness and distribution in the GOM and adds to our understanding of microzooplankton diversity in the ocean

Bacterial survival under extreme UV radiation: A comparative proteomics study of Rhodobacter sp., isolated from high altitude wetlands in Chile

Salar de Huasco, defined as a polyextreme environment, is a high altitude saline wetland in the Chilean Altiplano (3800 m.a.s.l.), permanently exposed to the highest solar radiation doses registered in the world. We present here the first comparative proteomics study of a photoheterotrophic bacterium, Rhodobacter sp., isolated from this remote and hostile habitat. We developed an innovative experimental approach using different sources of radiation (in situ sunlight and UVB lamps), cut-off filters (Mylar, Lee filters) and a high-throughput, label-free quantitative proteomics method to comprehensively analyze the effect of seven spectral bands on protein regulation. A hierarchical cluster analysis (HCA) of 40 common proteins revealed that all conditions containing the most damaging UVB radiation induced similar pattern of protein regulation compared with UVA and visible light spectral bands. Moreover, it appeared that the cellular adaptation of Rhodobacter sp. to osmotic stress encountered in the hypersaline environment from which it was originally isolated, might further a higher resistance to damaging UV radiation. Indeed, proteins involved in the synthesis and transport of key osmoprotectants, such as glycine betaine and inositol, were found in very high abundance under UV radiation compared to the dark control, suggesting the function of osmolytes as efficient reactive oxygen scavengers. Our study also revealed a RecA-independent response and a tightly regulated network of protein quality control involving proteases and chaperones to selectively degrade misfolded and/or damaged proteins

Impact of prior biologic use on persistence of treatment in patients with psoriatic arthritis enrolled in the US Corrona registry

Psoriatic arthritis (PsA) is a chronic condition characterized by a diverse set of symptoms, from swollen joints to nail disease to skin disease. A variety of treatment options are available, including tumor necrosis factor inhibitors (TNFis). Little is known about treatment persistence in patients with PsA who initiate TNFi therapy, with and without prior biologic use. This study assessed persistence in these subgroups of patients with PsA and identified factors associated with persistence. This retrospective study utilized data from the Corrona registry of patients with PsA-with or without prior biologic experience-who initiated TNFi therapy between October 1, 2002, and March 21, 2013. Kaplan-Meier curves estimated median time to nonpersistence (discontinuation or switch to another biologic). Cox proportional hazards models identified factors associated with TNFi nonpersistence. A total of 1241 TNFi initiations were identified: 549 by biologic-naive and 692 by biologic-experienced patients. Through 4 years of follow-up, more biologic-naive than biologic-experienced patients remained persistent. Biologic-naive patients had a greater mean time to nonpersistence compared with biologic-experienced patients: 32 vs 23 months (p = 0.0002). Moderate and high disease activities based on clinical disease activity index and disease duration were associated with persistence in both biologic-naive and biologic-experienced patients. Additionally, in the biologic-experienced patients, the number of prior medications and skin disease were associated with persistence. The majority of patients with PsA in this study were persistent with their TNFi therapy; biologic-naive patients had greater persistence compared with biologic-experienced patients. Predictors of persistence differed slightly between biologic-naive and biologic-experienced patients

SWOG S1400B (NCT02785913), a Phase II Study of GDC-0032 (Taselisib) for Previously Treated PI3K-Positive Patients with Stage IV Squamous Cell Lung Cancer (Lung-MAP Sub-Study).

BackgroundS1400B is a biomarker-driven Lung-MAP substudy evaluating the phosphatidylinositol 3-kinase (PI3K) inhibitor taselisib (GDC-0032) in patients with PI3K pathway-activated squamous NSCLC (sqNSCLC).MethodsEligible patients had tumoral phosphatidylinositol-4,5-biphosphate 3 kinase catalytic subunit alpha (PIK3CA) alterations by next-generation sequencing and disease progression after at least one line of platinum-based therapy. Patients received 4-mg taselisib orally daily. The primary analysis population (PAP) was a subset of patients having substitution mutations believed to be associated with clinical benefit of PI3K inhibitors. Primary endpoint was response by Response Evaluation Criteria in Solid Tumors version 1.1; secondary endpoints included progression-free survival, overall survival and duration of response.ResultsTwenty-six patients treated with taselisib comprised the full evaluable population (FEP); 21 patients comprised the PAP. Median age for patients in the FEP was 68 years (range: 53-83 years), 19 were male (73%). The study was closed for futility at interim analysis with one responder in the PAP (5% response rate, 95% confidence interval [CI]: 0%-24%). Two possibly treatment-related deaths (one respiratory failure, one cardiac arrest) were observed; one patient had grades 4 and 11 had grade 3 adverse events. Median progression-free survival and overall survival in the PAP group were 2.9 months (95% CI: 1.8-4.0 mo) and 5.9 months (95% CI: 4.2-7.8 mo), respectively. These numbers were nearly the same in the FEP.ConclusionsStudy S1400B evaluating taselisib in PIK3CA-altered sqNSCLC failed to meet its primary endpoint and was closed after an interim futility analysis. The trial is unique in cataloguing the diversity of PIK3CA mutations in sqNSCLC

Absolute dimensions of the unevolved B-type eclipsing binary GG Orionis

We present photometric observations in B and V as well as spectroscopic observations of the detached, eccentric 6.6-day double-lined eclipsing binary GG Ori, a member of the Orion OB1 association. Absolute dimensions of the components, which are virtually identical, are determined to high accuracy (better than 1% in the masses and better than 2% in the radii) for the purpose of testing various aspects of theoretical modeling. We obtain M(A) = 2.342 +/- 0.016 solar masses and R(A) = 1.852 +/- 0.025 solar radii for the primary, and M(B) = 2.338 +/- 0.017 solar masses and R(B) = 1.830 +/- 0.025 solar radii for the secondary. The effective temperature of both stars is 9950 +/- 200 K, corresponding to a spectral type of B9.5. GG Ori is very close to the ZAMS, and comparison with current stellar evolution models gives ages of 65-82 Myr or 7.7 Myr depending on whether the system is considered to be burning hydrogen on the main sequence or still in the final stages of pre-main sequence contraction. We have detected apsidal motion in the binary at a rate of dw/dt = 0.00061 +/- 0.00025 degrees per cycle, corresponding to an apsidal period of U = 10700 +/- 4500 yr. A substantial fraction of this (approximately 70%) is due to the contribution from General Relativity.Comment: To appear in The Astronomical Journal, December 200

Mechanisms of Impaired Exercise Capacity in Short Duration Experimental Hyperthyroidism

Abstract To investigate the mechanism of reduced exercise tolerance in hyperthyroidism, we characterized cardiovascular function and determinants of skeletal muscle metabolism in 18 healthy subjects aged 26±1 yr (mean±SE) before and after 2 wk of daily ingestion of 100 pg of triiodothyronine (T3). Resting oxygen uptake, heart rate, and cardiac output increased and heart rate and cardiac output at the same submaximal exercise intensity were higher in the hyperthyroid state (P < 0.05). However, maximal oxygen uptake decreased after T3 administration (3.08±0.17 vs. 2.94±0.19 l/min; P < 0.001) despite increased heart rate and cardiac output at maximal exercise (P < 0.05). Plasma lactic acid concentration at an equivalent submaximal exercise intensity was elevated 25% (P < 0.01) and the arteriovenous oxygen difference at maximal effort was reduced (P < 0.05) in the hyperthyroid state. These effects were associated with a 21-37% decline in activities of oxidative (P < 0.001) and glycolytic (P < 0.05) enzymes in skeletal muscle and a 15% decrease in type 11A muscle fiber cross-sectional area (P < 0.05). Lean body mass was reduced (P < 0.001) and the rates of whole body leucine oxidation and protein breakdown were enhanced (P < 0.05). Thus, exercise tolerance is impaired in short duration hyperthyroidism because of decreased skeletal muscle mass and oxidative capacity related to accelerated protein catabolism but cardiac pump function is not reduced. (J. Clin

Acute inhibition of bacterial growth in coastal seawater amended with crude oils with varied photoreactivities

The increased potential for contamination of seawater by crude oils requires studies of bacterial biodegradation potential, but little is known of the differential negative impacts of oils on bacterial growth. No two wells generate chemically identical oils; and importantly, solar exposure of crude oil may differentially affect the bacterial response. Elucidating the role that sunlight plays on the potential toxicity of spilled crude oils is imperative to understanding how oil spills might affect microbes in the tropical and subtropical waters of Florida. This study examined light exposure of six different crude oils, and subsequent microbial responses to altered oils. Marine bacterioplankton heterotrophic activities were measured via3H-leucine incorporation after the addition of oils’ water accommodated fractions (WAFs) that were created under varied solar conditions. Inhibition of production increased with higher concentrations of WAFs, but dose-response trends varied among the oils. Increased solar exposure during WAF preparation generally led to more inhibition, but trends varied among oils. WAFs were also prepared under different parts of the solar spectrum. Solar-irradiated WAFs resulted in significant but variable acute toxicity vs. dark counterparts. Solar-induced toxicity was primarily a result of visible and not ultraviolet light exposure. Results indicate responses to oil spills are highly dependent on the source of the oil and solar conditions at the time and location of the spill. The data presented here demonstrate the importance of photochemical changes and oil source in modulating microbial activity and bioremediation potential

Orbital Parameters for the Soft X-ray Transient 4U 1543-47: Evidence for a Black Hole

(shortened) Spectroscopic observations of the soft X-ray transient 4U 1543-47 reveal a radial velocity curve with a period of P=1.123 +/- 0.008 days and a semi-amplitude of K_2 = 124 +/- 4 km/sec. The mass function is f(M) = 0.22 +/- 0.02 solar masses. We derive a distance of d = 9.1 +/-1.1 kpc if the secondary is on the main sequence. The V and I light curves exhibit two waves per orbital cycle with amplitudes of about 0.08 mag. We modeled the light curves as ellipsoidal variations in the secondary star and derive extreme inclination limits of 20 <= i <= 40 deg and formal 3 sigma limits of 24 <= i <= 36 deg for a mass ratio Q = M_1/M_2 > 1. However, there are systematic effects in the data that the model does not account for, so the above constraints should be treated with caution. We argue that the secondary star is still on the main sequence and if the secondary star has a mass near the main sequence values for early A-stars (2.3 <= M_2 <= 2.6 solar masses), then the best fits for the 3 sigma inclination range (24 <= i <= 36 deg) and the 3 sigma mass function range (0.16 <= f(M) <= 0.28 solar masses) imply a primary mass in the range 2.7 <= M_1 <= 7.5 solar masses. Thus the mass of the compact object in 4U 1543-47 is likely to be in excess of approximately 3 solar masses and we conclude 4U 1543-47 most likely contains a black hole.Comment: 18 pages, 9 figures, LaTeX (uses the standard AAS style file aas2pp4.sty), accepted for publication in the Ap