Metagenome-assembled genome of the glacier alga Ancylonema yields insights into the evolution of streptophyte life on ice and land.

Contemporary glaciers are inhabited by streptophyte algae that balance photosynthesis and growth with tolerance of low temperature, desiccation and UV radiation. These same environmental challenges have been hypothesised as the driving force behind the evolution of land plants from streptophyte algal ancestors in the Cryogenian (720-635 million years ago). We sequenced, assembled and analysed the metagenome-assembled genome of the glacier alga Ancylonema nordenskiöldii to investigate its adaptations to life in ice, and whether this represents a vestige of Cryogenian exaptations.

Alpine glacier algal bloom during a record melt year.

Glacier algal blooms dominate the surfaces of glaciers and ice sheets during summer melt seasons, with larger blooms anticipated in years that experience the greatest melt. Here, we characterize the glacier algal bloom proliferating on Morteratsch glacier, Switzerland, during the record 2022 melt season, when the Swiss Alps lost three times more ice than the decadal average. Glacier algal cellular abundance (cells ml), biovolume (μm cell), photophysiology (F/F, rETR), and stoichiometry (C:N ratios) were constrained across three elevations on Morteratsch glacier during late August 2022 and compared with measurements of aqueous geochemistry and outputs of nutrient spiking experiments.

Cryogenian Origins of Multicellularity in Archaeplastida.

Earth was impacted by global glaciations during the Cryogenian (720 to 635 million years ago; Ma), events invoked to explain both the origins of multicellularity in Archaeplastida and radiation of the first land plants. However, the temporal relationship between these environmental and biological events is poorly established, due to a paucity of molecular and fossil data, precluding resolution of the phylogeny and timescale of archaeplastid evolution. We infer a time-calibrated phylogeny of early archaeplastid evolution based on a revised molecular dataset and reappraisal of the fossil record.

The impact of radiation therapy variables on pediatric high-grade glioma outcomes: A National Cancer Database analysis.

Purpose: The purpose of this analysis is to report patterns of care for pediatric patients with high-grade glioma (pHGG) and evaluate the impact of radiotherapy (RT) variables on outcomes using the National Cancer Database (NCDB).

Methods: Eligibility criteria included age < 22 years, histologically diagnosed WHO grade III-IV gliomas treated with ≥50 Gy and < 76 Gy RT between 2004 and 2013, and RT initiation within 90 days of diagnosis. RT variables including RT dose, RT timing, and RT modality were analyzed along with baseline demographic, tumor, and treatment variables to assess the impact on overall survival.

Adaptation versus plastic responses to temperature, light, and nitrate availability in cultured snow algal strains.

Snow algal blooms are widespread, dominating low temperature, high light, and oligotrophic melting snowpacks. Here, we assessed the photophysiological and cellular stoichiometric responses of snow algal genera Chloromonas spp. and Microglena spp.

A Once-Thought Lipoma Turned Malignant Chondroid Syringoma.

Chondroid syringoma is a relatively rare benign skin appendageal tumor with an incidence of <0.098%. Malignant chondroid syringoma (MCS) arises from cutaneous sweat glands and occurs on the extremities or trunk more commonly in women with only 51 reported cases.

The origin and early evolution of plants.

Plant (archaeplastid) evolution has transformed the biosphere, but we are only now beginning to learn how this took place through comparative genomics, phylogenetics, and the fossil record. This has illuminated the phylogeny of Archaeplastida, Viridiplantae, and Streptophyta, and has resolved the evolution of key characters, genes, and genomes - revealing that many key innovations evolved long before the clades with which they have been casually associated. Molecular clock analyses estimate that Streptophyta and Viridiplantae emerged in the late Mesoproterozoic to late Neoproterozoic, whereas Archaeplastida emerged in the late-mid Palaeoproterozoic.

Macro-Nutrient Stoichiometry of Glacier Algae From the Southwestern Margin of the Greenland Ice Sheet.

Glacier algae residing within the surface ice of glaciers and ice sheets play globally significant roles in biogeochemical cycling, albedo feedbacks, and melt of the world's cryosphere. Here, we present an assessment of the macro-nutrient stoichiometry of glacier algal assemblages from the southwestern Greenland Ice Sheet (GrIS) margin, where widespread glacier algal blooms proliferate during summer melt seasons. Samples taken during the mid-2019 ablation season revealed overall lower cellular carbon (C), nitrogen (N), and phosphorus (P) content than predicted by standard microalgal cellular content:biovolume relationships, and elevated C:N and C:P ratios in all cases, with an overall estimated C:N:P of 1,997:73:1.

Mineral phosphorus drives glacier algal blooms on the Greenland Ice Sheet.

Melting of the Greenland Ice Sheet is a leading cause of land-ice mass loss and cryosphere-attributed sea level rise. Blooms of pigmented glacier ice algae lower ice albedo and accelerate surface melting in the ice sheet's southwest sector. Although glacier ice algae cause up to 13% of the surface melting in this region, the controls on bloom development remain poorly understood.

Physiological Capabilities of Cryoconite Hole Microorganisms.

Cryoconite holes are miniature freshwater aquatic ecosystems that harbor a relatively diverse microbial community. This microbial community can withstand the extreme conditions of the supraglacial environment, including fluctuating temperatures, extreme and varying geochemical conditions and limited nutrients. We analyzed the physiological capabilities of microbial isolates from cryoconite holes from Antarctica, Greenland, and Svalbard in selected environmental conditions: extreme pH, salinity, freeze-thaw and limited carbon sources, to identify their physiological limits.

Over Winter Microbial Processes in a Svalbard Snow Pack: An Experimental Approach.

Snow packs cover large expanses of Earth's land surface, making them integral components of the cryosphere in terms of past climate and atmospheric proxies, surface albedo regulators, insulators for other Arctic environments and habitats for diverse microbial communities such as algae, bacteria and fungi. Yet, most of our current understanding of snow pack environments, specifically microbial activity and community interaction, is limited to the main microbial growing season during spring ablation. At present, little is known about microbial activity and its influence on nutrient cycling during the subfreezing temperatures and 24-h darkness of the polar winter.

Algal photophysiology drives darkening and melt of the Greenland Ice Sheet.

Blooms of Zygnematophycean "glacier algae" lower the bare ice albedo of the Greenland Ice Sheet (GrIS), amplifying summer energy absorption at the ice surface and enhancing meltwater runoff from the largest cryospheric contributor to contemporary sea-level rise. Here, we provide a step change in current understanding of algal-driven ice sheet darkening through quantification of the photophysiological mechanisms that allow glacier algae to thrive on and darken the bare ice surface. Significant secondary phenolic pigmentation (11 times the cellular content of chlorophyll ) enables glacier algae to tolerate extreme irradiance (up to ∼4,000 µmol photons⋅m⋅s) while simultaneously repurposing captured ultraviolet and short-wave radiation for melt generation.

Cell membrane fatty acid and pigment composition of the psychrotolerant cyanobacterium Nodularia spumigena CHS1 isolated from Hopar glacier, Pakistan.

In the present study, cyanobacterium isolate CHS1 isolated from Hopar glacier, Pakistan, was analyzed for the first time for cell membrane fatty acids and production of pigments. Sequencing of the 16-23S intergenetic region confirmed identification of the isolate CHS1 as Nodularia spumigena. All chlorophyll and carotenoid pigments were quantified using high-performance liquid chromatography and experiments to test tolerance against a range of physico-chemical conditions were conducted.

Bacterial Dynamics in Supraglacial Habitats of the Greenland Ice Sheet.

Current research into bacterial dynamics on the Greenland Ice Sheet (GrIS) is biased toward cryoconite holes, despite this habitat covering less than 8% of the ablation (melt) zone surface. In contrast, the expansive surface ice, which supports wide-spread Streptophyte micro-algal blooms thought to enhance surface melt, has been relatively neglected. This study aims to understand variability in bacterial abundance and production across an ablation season on the GrIS, in relation to micro-algal bloom dynamics.

Glacier Algae: A Dark Past and a Darker Future.

"Glacier algae" grow on melting glacier and ice sheet surfaces across the cryosphere, causing the ice to absorb more solar energy and consequently melt faster, while also turning over carbon and nutrients. This makes glacier algal assemblages, which are typically dominated by just three main species, a potentially important yet under-researched component of the global biosphere, carbon, and water cycles. This review synthesizes current knowledge on glacier algae phylogenetics, physiology, and ecology.

Darkening of the Greenland Ice Sheet: Fungal Abundance and Diversity Are Associated With Algal Bloom.

Recent studies have highlighted the importance of ice-algal blooms in driving darkening and therefore surface melt of the Greenland Ice Sheet (GrIS). However, the contribution of fungal and bacterial communities to this microbially driven albedo reduction remains unconstrained. To address this significant knowledge gap, fungi were isolated from key GrIS surface habitats (surface ice containing varying abundance of ice algae, supraglacial water, cryoconite holes, and snow), and a combination of cultivation and sequencing methods utilized to characterize the algal-associated fungal and bacterial diversity and abundance.

Photoecology of the Antarctic cyanobacterium Leptolyngbya sp. BC1307 brought to light through community analysis, comparative genomics and in vitro photophysiology.

Cyanobacteria are important photoautotrophs in extreme environments such as the McMurdo Dry Valleys, Antarctica. Terrestrial Antarctic cyanobacteria experience constant darkness during the winter and constant light during the summer which influences the ability of these organisms to fix carbon over the course of an annual cycle. Here, we present a unique approach combining community structure, genomic and photophysiological analyses to understand adaptation to Antarctic light regimes in the cyanobacterium Leptolyngbya sp.

Elevated Radiation Exposure Associated With Above Surface Flat Detector Mini C-Arm Use.

This study aims to test the hypothesis that: (1) radiation exposure is increased with the intended use of Flat Surface Image Intensifier (FSII) units above the operative surface compared with the traditional below-table configuration; (2) this differential increases in a dose-dependent manner; and (3) radiation exposure varies with body part and proximity to the radiation source. A surgeon mannequin was seated at a radiolucent hand table, positioned for volar distal radius plating. Thermoluminescent dosimeters measured exposure to the eyes, thyroid, chest, hand, and groin, for 1- and 15-minute trials from a mini C-arm FSII unit positioned above and below the operating surface.

Mini C-Arm Fluoroscopy: Does Its Configuration Matter for Radiation Exposure to the Surgeon?

Background: The risk of occupational radiation exposure to the surgeon associated with the use of a mini C-arm has yet to reach a wide consensus. Using a distal radius fracture surgery model, we tested the hypothesis that radiation exposure to the surgeon's critical body parts is independent of mini C-arm configuration.

Methods: An anthropomorphic mannequin (representing the upper body of a 60" male surgeon) was seated at a hand table as if operating on a volar-plated wrist Sawbone model.

Photoacclimation by Arctic cryoconite phototrophs.

Cryoconite is a matrix of sediment, biogenic polymer and a microbial community that resides on glacier surfaces. The phototrophic component of this community is well adapted to this extreme environment, including high light stress. Photoacclimation of the cryoconite phototrophic community on Longyearbreen, Svalbard, was investigated using in situ variable chlorophyll fluorescence.

Characterising the microbiome of Corallina officinalis, a dominant calcified intertidal red alga.

The living prokaryotic microbiome of the calcified geniculate (articulated) red alga, Corallina officinalis from the intertidal seashore is characterised for the first time based on the V6 hypervariable region of 16S rRNA. Results revealed an extraordinary diversity of bacteria associated with the microbiome. Thirty-five prokaryotic phyla were recovered, of which Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Acidobacteria, Verrucomicrobia, Firmicutes and Chloroflexi made up the core microbiome.

Response of Antarctic cryoconite microbial communities to light.

Microbial communities on polar glacier surfaces are found dispersed on the ice surface, or concentrated in cryoconite holes and cryolakes, which are accumulations of debris covered by a layer of ice for some or all of the year. The ice lid limits the penetration of photosynthetically available radiation (PAR) to the sediment layer, since the ice attenuates up to 99% of incoming radiation. This suite of field and laboratory experiments demonstrates that PAR is an important control on primary production in cryoconite and cryolake ecosystems.

Complete mitochondrial genome of the geniculate calcified red alga, (Corallinales, Rhodophyta).

We present the first mitochondrial genome of the calcified, geniculate coralline red alga (Corallinales). The circular genome consists of 26,504 bp and has a gene content consisting of 23 protein-coding genes, 26 transfer RNA genes and two ribosomal RNA genes, with an overall GC content of 30.1%.

The future of the northeast Atlantic benthic flora in a high CO2 world.

Seaweed and seagrass communities in the northeast Atlantic have been profoundly impacted by humans, and the rate of change is accelerating rapidly due to runaway CO2 emissions and mounting pressures on coastlines associated with human population growth and increased consumption of finite resources. Here, we predict how rapid warming and acidification are likely to affect benthic flora and coastal ecosystems of the northeast Atlantic in this century, based on global evidence from the literature as interpreted by the collective knowledge of the authorship. We predict that warming will kill off kelp forests in the south and that ocean acidification will remove maerl habitat in the north.

Low ATM protein expression and depletion of p53 correlates with olaparib sensitivity in gastric cancer cell lines.

Small-molecule inhibitors of poly (ADP-ribose) polymerase (PARP) have shown considerable promise in the treatment of homologous recombination (HR)-defective tumors, such as BRCA1- and BRCA2-deficient breast and ovarian cancers. We previously reported that mantle cell lymphoma cells with deficiency in ataxia telangiectasia mutated (ATM) are sensitive to PARP-1 inhibitors in vitro and in vivo. Here, we report that PARP inhibitors can potentially target ATM deficiency arising in a solid malignancy.