Can acclimation of thermal tolerance, in adults and across generations, act as a buffer against climate change in tropical marine ectotherms?

Thermal acclimation capacity was investigated in adults of three tropical marine invertebrates, the subtidal barnacle Striatobalanus amaryllis, the intertidal gastropod Volegalea cochlidium and the intertidal barnacle Amphibalanus amphitrite. To test the relative importance of transgenerational acclimation, the developmental acclimation capacity of A. amphitrite was investigated in F1 and F2 generations reared at a subset of the same incubation temperatures. The increase in CTmax (measured through loss of key behavioural metrics) of F0 adults across the incubation temperature range 25.4-33.4°C was low: 0.00°C (V. cochlidium), 0.05°C (S. amaryllis) and 0.06°C (A. amphitrite) per 1°C increase in incubation temperature (the acclimation response ratio; ARR). Although the effect of generation was not significant, across the incubation temperature range of 29.4-33.4°C, the increase in CTmax in the F1 (0.30°C) and F2 (0.15°C) generations of A. amphitrite was greater than in the F0 (0.10°C). These correspond to ARR's of 0.03°C (F0), 0.08°C (F1) and 0.04°C (F2), respectively. The variability in CTmax between individuals in each treatment was maintained across generations, despite the high mortality of progeny. Further research is required to investigate the potential for transgenerational acclimation to provide an extra buffer for tropical marine species facing climate warming.

Multi-omics for studying and understanding polar life.

Polar ecosystems are experiencing amongst the most rapid rates of regional warming on Earth. Here, we discuss 'omics' approaches to investigate polar biodiversity, including the current state of the art, future perspectives and recommendations. We propose a community road map to generate and more fully exploit multi-omics data from polar organisms. These data are needed for the comprehensive evaluation of polar biodiversity and to reveal how life evolved and adapted to permanently cold environments with extreme seasonality. We argue that concerted action is required to mitigate the impact of warming on polar ecosystems via conservation efforts, to sustainably manage these unique habitats and their ecosystem services, and for the sustainable bioprospecting of novel genes and compounds for societal gain.

Under pressure: Nanoplastics as a further stressor for sub-Antarctic pteropods already tackling ocean acidification.

In the Southern Ocean (SO), plastic debris has already been found in waters and sediments. Nanoplastics (<1 µm) are expected to be as pervasive as their larger counterparts, but more harmful to biological systems, being able to enter cells and provoke toxicity. In the SO, (nano)plastic pollution occurs concomitantly with other environmental threats such as ocean acidification (OA), but the potential cumulative impact of these two challenges on SO marine ecosystems is still overlooked. Here the single and combined effects of nanoplastics and OA on the sub-Antarctic pteropod Limacina retroversa are investigated under laboratory conditions, using two surface charged polystyrene nanoparticles (PS NPs) as a proxy for nanoplastics. Sub-Antarctic pteropods are threatened by OA due to the sensitivity of their shells to changes in seawater carbonate chemistry. Short-term exposure (48 h) to PS NPs compromised the ability of pteropods to counteract OA stress, resulting in a negative effect on their survival. Our results highlights the importance of addressing plastic pollution in the context of climate change to identify realistic critical thresholds of SO pteropods.

Temperatures leading to heat escape responses in Antarctic marine ectotherms match acute thermal limits.

Thermal tolerance windows are key indicators of the range of temperatures tolerated by animals and therefore, a measure of resilience to climate change. In the ocean, where ectotherms are immersed, body temperatures are tightly coupled to environmental temperature and species have few options for thermoregulation. However, mobile species do have the ability to orientate towards optimal temperatures and move away from sub-optimal or dangerous temperatures. Escape responses are one such locomotory behavior, which typically manifests as a series of violent flicking movements that move individuals out of dangerous environments. We tested 11 species of Antarctic marine ectotherms, from one of the most stable shallow water marine environments, with an annual temperature range of -2°C to +2°C, that are vulnerable to small degrees of warming. Three species, the clam Laternula elliptica, the sea cucumber Cucumaria georgiana, and the brittlestar Ophionotus victoriae, showed no, or virtually no, escape response to temperature. Escape responses from a further eight species had a median response temperature of 11.2 (interquartile range, 10°C-15.7°C), which is well above current environmental temperatures but close to the range for acute lethal limits of Antarctic marine ectotherms (CTmax range, 17.2°C-26.6°C). This highlights that both acute tolerance limits and escape responses, fall outside current environmental temperatures, but also those predicted for 100s of years in the Southern Ocean. In a warmer Southern Ocean Antarctic fauna may not have the capacity to use temperature to select optimal thermal conditions, which leaves adaptation as a primary mechanism for their persistence.

Metabarcoding the Antarctic Peninsula biodiversity using a multi-gene approach.

Marine sediment communities are major contributors to biogeochemical cycling and benthic ecosystem functioning, but they are poorly described, particularly in remote regions such as Antarctica. We analysed patterns and drivers of diversity in metazoan and prokaryotic benthic communities of the Antarctic Peninsula with metabarcoding approaches. Our results show that the combined use of mitochondrial Cox1, and 16S and 18S rRNA gene regions recovered more phyla, from metazoan to non-metazoan groups, and allowed correlation of possible interactions between kingdoms. This higher level of detection revealed dominance by the arthropods and not nematodes in the Antarctic benthos and further eukaryotic diversity was dominated by benthic protists: the world's largest reservoir of marine diversity. The bacterial family Woeseiaceae was described for the first time in Antarctic sediments. Almost 50% of bacteria and 70% metazoan taxa were unique to each sampled site (high alpha diversity) and harboured unique features for local adaptation (niche-driven). The main abiotic drivers measured, shaping community structure were sediment organic matter, water content and mud. Biotic factors included the nematodes and the highly abundant bacterial fraction, placing protists as a possible bridge for between kingdom interactions. Meiofauna are proposed as sentinels for identifying anthropogenic-induced changes in Antarctic marine sediments.

Antimicrobial resistance in Antarctica: is it still a pristine environment?

Although the rapid spread of antimicrobial resistance (AMR), particularly in relation to clinical settings, is causing concern in many regions of the globe, remote, extreme environments, such as Antarctica, are thought to be relatively free from the negative impact of human activities. In fact, Antarctica is often perceived as the last pristine continent on Earth. Such remote regions, which are assumed to have very low levels of AMR due to limited human activity, represent potential model environments to understand the mechanisms and interactions underpinning the early stages of evolution, de novo development, acquisition and transmission of AMR. Antarctica, with its defined zones of human colonisation (centred around scientific research stations) and large populations of migratory birds and animals, also has great potential with regard to mapping and understanding the spread of early-stage zoonotic interactions. However, to date, studies of AMR in Antarctica are limited. Here, we survey the current literature focussing on the following: i) Dissection of human-introduced AMR versus naturally occurring AMR, based on the premise that multiple drug resistance and resistance to synthetic antibiotics not yet found in nature are the results of human contamination ii) The potential role of endemic wildlife in AMR spread There is clear evidence for greater concentrations of AMR around research stations, and although data show reverse zoonosis of the characteristic human gut bacteria to endemic wildlife, AMR within birds and seals appears to be very low, albeit on limited samplings. Furthermore, areas where there is little, to no, human activity still appear to be free from anthropogenically introduced AMR. However, a comprehensive assessment of AMR levels in Antarctica is virtually impossible on current data due to the wide variation in reporting standards and methodologies used and poor geographical coverage. Thus, future studies should engage directly with policymakers to promote the implementation of continent-wide AMR reporting standards. The development of such standards alongside a centralised reporting system would provide baseline data to feedback directly into wastewater treatment policies for the Antarctic Treaty Area to help preserve this relatively pristine environment. Video Abstract.

Oxygen administration and monitoring for ward adult patients in a teaching hospital.

AIM: The aims of this study were to describe oxygen administration and respiratory monitoring of ward patients in a tertiary teaching hospital, and to assess differences in characteristics and outcomes between patients who are receiving versus are not receiving oxygen. METHODS: Prospective clinical audit of all non-ventilated adult ward patients in a tertiary teaching hospital in Melbourne, Victoria on 26 August 2009. RESULTS: All 323 eligible patients were audited (medical 218, surgical 105). At assessment, 76 patients (24%) were on oxygen therapy and of these, 57 patients (74%) received oxygen by nasal prongs. Overall, oxygen saturation was documented in 301 (93.2%) patients and respiratory rate (RR) documented in 283 patients (87.6%). Patients receiving oxygen had a lower median SpO(2) (94% vs 96%, P < 0.0001), higher median RR (20/min vs 18/min, P < 0.0005); and were older (68.8 v 63.1 years, P= 0.0094). The in-hospital mortality of patients receiving oxygen therapy was 15.8% compared with 5.3% for those not on oxygen (P < 0.0056). CONCLUSION: Oxygen is administered to one-quarter of ward patients in our hospital. Oxygen saturation and RR are not documented in approximately 10% of patients. Oxygen therapy in ward patients identifies individuals with increased mortality. Continuing educational interventions to increase awareness of the high-risk status of these patients and strategies to detect patients at risk of hypoxaemia are needed.

Sources of elevated heavy metal concentrations in sediments and benthic marine invertebrates of the western Antarctic Peninsula.

Antarctica is one of the least anthropogenically-impacted areas of the world. Metal sources to the marine environment include localised activities of research stations and glacial meltwater containing metals of lithogenic origin. In this study, concentrations of nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) were examined in three species of benthic invertebrates collected from four locations near Rothera Research Station on the western Antarctic Peninsula: Laternula elliptica (mudclam, filter feeder), Nacella concinna (limpet, grazer) and Odontaster validus (seastar, predator and scavenger). In addition, metals were evaluated in sediments at the same locations. Metal concentrations in different body tissues of invertebrates were equivalent to values recorded in industrialized non-polar sites and were attributed to natural sources including sediment input resulting from glacial erosion of local granodioritic rocks. Anthropogenic activities at Rothera Research Station appeared to have some impact on metal concentrations in the sampled invertebrates, with concentrations of several metals higher in L. elliptica near the runway and aircraft activities, but this was not a trend that was detected in the other species. Sediment analysis from two sites near the station showed lower metal concentrations than the control site 5 km distant and was attributed to differences in bedrock metal content. Differences in metal concentrations between organisms were attributed to feeding mechanisms and habitat, as well as depuration routes. L. elliptica kidneys showed significantly higher concentrations of eight metals, with some an order of magnitude greater than other organs, and the internal structure of O. validus had significantly higher Ni. This study supports previous assessments of N. concinna and L. elliptica as good biomonitors of metal concentrations and suggests O. validus as an additional biomonitor for use in future Antarctic metal monitoring programs.

Quantitative chemical analysis of lunar samples.

In three lunar samples the high titanium contents previously reported were confirmed. Water and ferric oxide were absent.

One hundred questions of importance to the conservation of global biological diversity.

We identified 100 scientific questions that, if answered, would have the greatest impact on conservation practice and policy. Representatives from 21 international organizations, regional sections and working groups of the Society for Conservation Biology, and 12 academics, from all continents except Antarctica, compiled 2291 questions of relevance to conservation of biological diversity worldwide. The questions were gathered from 761 individuals through workshops, email requests, and discussions. Voting by email to short-list questions, followed by a 2-day workshop, was used to derive the final list of 100 questions. Most of the final questions were derived through a process of modification and combination as the workshop progressed. The questions are divided into 12 sections: ecosystem functions and services, climate change, technological change, protected areas, ecosystem management and restoration, terrestrial ecosystems, marine ecosystems, freshwater ecosystems, species management, organizational systems and processes, societal context and change, and impacts of conservation interventions. We anticipate that these questions will help identify new directions for researchers and assist funders in directing funds.

Heart rate and ventilation in Antarctic fishes are largely determined by ecotype.

Extrinsic neural and humoral influences on heart rate (fH) and ventilation frequency (fV) were examined following varying periods of post-surgical recovery in eight related Antarctic fish species inhabiting an array of inshore niches. Resting fH after recovery from handling was lower than previous reports, and the novel measurement of routine fH in free-swimming Dissostichus mawsoni (6.14 beats min(-1), bpm) is the lowest recorded for any fish. The extent of cardio-depressive cholinergic (vagal) tonus explained the large range of fH among species and varied with behavioural repertoire, being lower in the more active species, apart from Notothenia coriiceps. Adrenergic tonus was low compared with cholinergic tonus, with the exception of Trematomus newnesi. Hence, high cardiac cholinergic tonus may be a genotypic trait of the notothenioids that diverged with ecotype. Power spectral analysis showed that the vagal influence produced comparable spectra among species of similar morphology and ecotype. Removal of autonomic tonus resulted in a remarkably similar intrinsic fH between species. Simultaneous measurements of cardio-respiratory variables and oxygen consumption (M(O(2))) were made in the benthic Trematomus bernacchii and cryopelagic Pagothenia borchgrevinki. The slopes of the relationship between fH and M(O(2)) were similar. Trematomus bernacchii, however, had a higher M(O(2)) for a given fH than P. borchgrevinki, and P. borchgrevinki required a two-fold larger range in fH to reach a similar maximum M(O(2)), suggesting that there is a difference in cardiovascular fitness between the two species. Overall, the data suggest that cardio-respiratory control in Antarctic nototheniids is largely determined by activity levels associated with a given ecotype.

Persistent Organic Pollutants in two species of migratory birds from Rothera Point, Adelaide Island, Antarctica.

Carcasses of South Polar Skuas (Catharacta maccormicki) and Kelp gulls (Larus dominicanus) were opportunistically collected around of Rothera Research station (67°35'8″S and 68°7'59″W) during the 2016/2017 austral summer. Samples of their tissues (muscle, liver and subcutaneous fat) were analysed for Persistent Organic Pollutants (POPs). Organochlorine pesticides (OCPs) showed the highest concentrations, notably for pp'-DDE and HCB. The Polychlorinated biphenyls (PCBs)-profiles demonstrated a clear dominance of hexa- and hepta-CBs, while concentrations of polybrominated diphenyl ethers (PBDEs) remained low. The concentrations of some POPs (e.g. HCB) were lower than in past studies on similar species, however others were within the previous range (PCBs) or even higher than previous reported values (DDE). Although no major interspecific differences in the absolute concentrations of POPs were detected, their profiles varied, being likely related to feeding and migration patterns of each species. The current study provides important baseline data for future monitoring of POPs in Antarctica.

Transcriptionally inactive oocyte-type 5S RNA genes of Xenopus laevis are complexed with TFIIIA in vitro.

An extract from whole oocytes of Xenopus laevis was shown to transcribe somatic-type 5S RNA genes approximately 100-fold more efficiently than oocyte-type 5S RNA genes. This preference was at least 10-fold greater than the preference seen upon microinjection of 5S RNA genes into oocyte nuclei or upon in vitro transcription in an oocyte nuclear extract. The approximately 100-fold transcriptional bias in favor of the somatic-type 5S RNA genes observed in vitro in the whole oocyte extract was similar to the transcriptional bias observed in developing Xenopus embryos. We also showed that in the whole oocyte extract, a promoter-binding protein required for 5S RNA gene transcription, TFIIIA, was bound both to the actively transcribed somatic-type 5S RNA gene and to the largely inactive oocyte-type 5S RNA genes. These findings suggest that the mechanism for the differential expression of 5S RNA genes during Xenopus development does not involve differential binding of TFIIIA to 5S RNA genes.

Age-related thermal response: the cellular resilience of juveniles.

Understanding species' responses to environmental challenges is key to predicting future biodiversity. However, there is currently little data on how developmental stages affect responses and also whether universal gene biomarkers to environmental stress can be identified both within and between species. Using the Antarctic clam, Laternula elliptica, as a model species, we examined both the tissue-specific and age-related (juvenile versus mature adult) gene expression response to acute non-lethal warming (12 h at 3 °C). In general, there was a relatively muted response to this sub-lethal thermal challenge when the expression profiles of treated animals, of either age, were compared with those of 0 °C controls, with none of the "classical" stress response genes up-regulated. The expression profiles were very variable between the tissues of all animals, irrespective of age with no single transcript emerging as a universal biomarker of thermal stress. However, when the expression profiles of treated animals of the different age groups were directly compared, a very different pattern emerged. The profiles of the younger animals showed significant up-regulation of chaperone and antioxidant transcripts when compared with those of the older animals. Thus, the younger animals showed evidence of a more robust cellular response to warming. These data substantiate previous physiological analyses showing a more resilient juvenile population.

Intravenous fluid bolus therapy: a bi-national survey of critical care nurses' self-reported practice.

Knowledge of critical care nurses' intravenous fluid bolus therapy (FBT) practice remains underexplored. Using a multi-choice online survey conducted between September and October 2014, we sought to describe the self-reported practice of critical care nurses located in Australia and New Zealand. Two hundred and ninety-five critical care nurses responded to the survey with most practising in adult ICUs. Overall, 0.9% saline solution was the preferred solution for FBT. However, more Australian than New Zealand respondents preferred 'albumin 4%' (31% versus 3.6%, P <0.01) for FBT. In contrast, more New Zealand respondents preferred 'Plasma-Lyte®' (33.3% versus 6.4%, P <0.01). Half of the respondents defined FBT as 250 ml administered as quickly as possible. However, FBT volumes ranged from 100 ml to >1000 ml and administration duration from as quickly as possible to 60 minutes. In response to FBT, almost half of the respondents expected an increase in mean arterial pressure of between 11 to 20 mmHg. Similarly, >40% expected a central venous pressure increase >3 mmHg, >70% expected a urinary output increase of 0.5 to 1.0 ml/kg/hr, and >60% expected a decrease in heart rate of >11 /min. Overall, 0.9% saline remains the most common solution for FBT, but there are significant national differences in the preference for albumin and Plasma-Lyte. A volume of 250 ml defines a fluid bolus, with a range from 100 ml to >1000 ml, and speed of delivery from stat to 60 minutes. Most nurses expect substantial physiological effects with FBT.

Kinetic control of 5 S RNA gene transcription.

We have determined that the differential transcription of somatic and oocyte-type 5 S RNA genes in a Xenopus laevis oocyte extract is a consequence of vastly different rates of stable complex assembly. Somatic-type 5 S RNA genes sequester a limiting transcription factor much more rapidly than oocyte-type 5 S RNA genes. Once formed, however, transcription complexes on both types of genes are stable, and are transcribed at nearly equivalent rates. The relative rates of stable transcription complex assembly are strongly dependent on the concentration of Mg2+. Kinetic differences in transcription complex assembly provides a key distinguishing feature between these two genes which may be used in the selective repression of oocyte-type 5 S RNA genes during the early development of Xenopus, and may also be utilized in other systems of regulated gene expression.

Rate of B to Z structural transition of supercoiled DNA.

The forward rate of the B to Z transition induced by negative supercoiling of plasmid DNA containing an alternating C-G sequence has been examined using the binding of Z-DNA-specific antibodies to follow the transition. DNA samples of a plasmid containing a d(pCpG)16 X d(pCpG)16 insert were supercoiled to different extents and appropriate amounts of ethidium were bound to the DNAs to relax them and to keep the alternating C-G sequence in the right-hand helical form. Following the rapid removal of ethidium by passage through a column of cation exchange resin, the DNA becomes negatively supercoiled, which induces the flipping of the helical hand of the C-G insert. The rate of the transition is strongly dependent on the degree of supercoiling. The transition is complete in less than 50 seconds for a DNA with a specific linking difference (superhelical density) sigma of -0.09. For the same DNA, the half-time of the transition is about two minutes at sigma = -0.07 and about a factor of 10 slower at sigma = -0.05.

Urinary neutrophil gelatinase-associated lipocalin to hepcidin ratio as a biomarker of acute kidney injury in intensive care unit patients.

BACKGROUND: Labile iron is important in the pathogenesis of acute kidney injury (AKI). Neutrophil gelatinase-associated lipocalin (NGAL) and hepcidin control iron metabolism and are upregulated during renal stress. However, higher levels of urinary NGAL are associated with AKI severity whereas higher urinary hepcidin levels are associated with absence of AKI. We aimed to investigate the value of combining both biomarkers to estimate the severity and progression of AKI in intensive care unit (ICU) patients. METHODS: Urinary NGAL and hepcidin were quantified within 48 hours of ICU admission in patients with the systemic inflammatory response syndrome and early kidney dysfunction (oliguria for ≥ 2 hours and/or a 25 µmol/L creatinine rise from baseline). Diagnostic and prognostic characteristics were assessed by logistic regression and receiver operating characteristics (ROC) analysis. RESULTS: Of 102 patients, 26 had mild AKI and 28 patients had severe AKI on admission. Sepsis (21%), cardiac surgery (17%) and liver failure (9%) were primary admission diagnoses. NGAL increased (P=0.03) whereas hepcidin decreased (P=0.01) with increasing AKI severity. The value of NGAL/hepcidin ratio to detect severe AKI was higher than when NGAL and hepcidin were used individually and persisted after adjusting for potential confounders (adjusted OR 2.40, 95% CI 1.20-4.78). The ROC areas for predicting worsening AKI were 0.50, 0.52 and 0.48 for NGAL, 1/hepcidin and the NGAL/hepcidin ratio. CONCLUSION: The NGAL/hepcidin ratio is more strongly associated with severe AKI than the single biomarkers alone. NGAL and hepcidin, alone or combined as a ratio, were unable to predict progressive AKI in this selected ICU cohort.

Effect of three sources of long-chain fatty acids on the plasma fatty acid profile, plasma prostaglandin E2 concentrations, and pruritus symptoms in hemodialysis patients.

Patients with chronic renal failure exhibit plasma fatty acid patterns indicative of essential fatty acid deficiency. The plasma fatty acid profile of 25 hemodialysis patients with a history of pruritus symptoms indicated lower 20:3n-9 (eicosatrienoic acid), 20:4n-6 (arachidonic acid), and 20:5n-3 (eicosapentaenoic acid) concentrations; a higher 18:1n-9 (oleic acid) concentration; and above-normal ranges of prostaglandin E2 (PGE2) compared with 22 subjects chosen from a normal population. No significant difference in 22:6n-3 (docosahexaenoic acid) was shown between the hemodialysis patients and the normal subjects. The dietary intake of 20:5n-3 was higher and that of 18:1n-9 lower in the patients compared with the normal population group. In this 8-wk double-blind study the hemodialysis patients were randomly assigned to receive daily supplements of 6 g ethyl ester of either fish oil, olive oil, or safflower oil. At the end of 8 wk of treatment the fish oil group (FO group) had a greater decrease in 18:1n-9 (P < 0.05), greater increases in 20:5n-3 and 22:6n-3 (P < 0.01), and trends toward a greater decrease in 20:4n-6, a greater increase in PGE2 concentrations, and greater improvement in pruritus scores (0.10 > P > 0.05) compared with the other two groups. The increases in 20:5n-3 and 22:6n-3 in the FO group indicate compliance with fish oil supplementation. Results indicate that hemodialysis patients have abnormal fatty acid profiles and increased PGE2 values. Fish oil intervention changes the fatty acid profile and may improve the symptoms of pruritus.