Switch from sexual to parthenogenetic reproduction in a zebra shark

Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to parthenogenetic reproduction in a shark species, the zebra shark Stegostoma fasciatum. A co-housed, sexually produced daughter zebra shark also commenced parthenogenetic reproduction at the onset of maturity without any prior mating. The demonstration of parthenogenesis in these two conspecific individuals with different sexual histories provides further support that elasmobranch fishes may flexibly adapt their reproductive strategy to environmental circumstances

Biodeterioration and bioprotection of concrete assets in the coastal environment

The deleterious effects (biodeterioration) and the protective benefits (bioprotection) of biological colonisation on manmade structures have long been debated. Lichens, biofilms, algae, bivalves and gastropods contribute both directly and indirectly to damaging substrata in the coastal zone which can enhance abiotic erosive forces that exploit biologically induced superficial damage. There is mounting evidence that these same species may also provide protective benefits. This debate often impacts approaches to managing fouling on concrete assets in the coastal environment. The net benefit or detriment a species or assemblage has on a structure is spatially and temporally dynamic and subject to the influence of various abiotic and biotic factors at different scales. However, the net outcome may be more pronounced under different contexts, particularly under warming and ocean acidifying climate change scenarios which is where further research should focus. Additionally, as bioprotection represents a potentially valuable ecosystem service, it supports the argument for increasing and improving habitat availability and biodiversity on artificial coastal structures via ecological enhancement. Quantifying bioprotection in useful metrics, such as monetary value or time added to serviceable life, would help demonstrate the benefits of bioprotective species in a meaningful wa

Evidence Of Protein Collective Motions On The Picosecond Time Scale

We investigate the presence of structural collective motions on a picosecond time scale for the heme protein, cytochrome c, as a function of oxidation and hydration, using terahertz (THz) time-domain spectroscopy and molecular dynamics simulations. The THz response dramatically increases with oxidation, with the largest increase for lowest hydrations and highest frequencies. For both oxidation states the THz response rapidly increases with hydration saturating above ~25% (g H2O/g protein). Quasi-harmonic vibrational modes and dipole-dipole correlation functions are calculated from molecular dynamics trajectories. The collective mode density of states alone reproduces the measured hydration dependence providing strong evidence of the existence of these motions. The large oxidation dependence is reproduced only by the dipole-dipole correlation function, indicating the contrast arises from diffusive motions consistent with structural changes occurring in the vicinity of a buried internal water molecule

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Do People Plan Ahead?

A crucial basic assumption of economic theories of dynamic behaviour is that people plan ahead. This paper reports on an extremely simple experimental test of this fundamental principle. Indeed the experiment is so simple and so straightforward that it is difficult to believe that anyone would not plan ahead. However subjects are found who do not. What are they doing

Effect of denosumab on trabecular bone score in postmenopausal women with osteoporosis.

Trabecular bone score (TBS) assesses bone quality in the lumbar spine using dual-energy X-ray absorptiometry (DXA) scans. In postmenopausal women with osteoporosis, denosumab significantly improved TBS independently of bone mineral density (BMD). This practical technique may have a role in managing patients with osteoporosis. TBS, a gray-level texture index determined from lumbar spine DXA scans, correlates with bone microarchitecture and enhances assessment of vertebral fracture risk independently of BMD. In the FREEDOM study, denosumab increased BMD and reduced new vertebral fractures in postmenopausal women with osteoporosis. This retrospective analysis explored the effect of denosumab on TBS and the association between TBS and BMD in FREEDOM. Postmenopausal women with lumbar spine or total hip BMD T-score <-2.5 and -4.0 or higher at both sites received placebo or denosumab 60 mg subcutaneously every 6 months. TBS indices were determined from DXA scans at baseline and months 12, 24, and 36 in a subset of 285 women (128 placebo, 157 denosumab) who had TBS values at baseline and ≥1 postbaseline visit. Baseline characteristics were comparable between treatment groups; mean (SD) lumbar spine BMD T-score was -2.79 (0.64), and mean (standard deviation [SD]) TBS was 1.200 (0.101) overall. In the placebo group, BMD and TBS increased by ≤0.2% or decreased from baseline at each visit. In the denosumab group, progressive increases from baseline at 12, 24, and 36 months were observed for BMD (5.7, 7.8, and 9.8%) and TBS (1.4, 1.9, and 2.4%). Percentage changes in TBS were statistically significant compared with baseline (p < 0.001) and placebo (p ≤ 0.014). TBS was largely unrelated to BMD, regardless of treatment, either at baseline or for annual changes from baseline (all r <sup>2</sup>  ≤ 0.06). In postmenopausal women with osteoporosis, denosumab significantly improved TBS independently of BMD

An investigation of avoidance by Antarctic krill of RRS "James Clark Ross" using the Autosub-2 autonomous underwater vehicle

The autonomous underwater vehicle (AUV) Autosub-2 was deployed on eight missions ahead of RRS James Clark Ross in the northern Weddell Sea and in the Bransfield Strait, Southern Ocean, to assess avoidance of the research vessel by Antarctic krill Euphausia superba. The AUV was equipped with the same type of scientific echosounder as the research vessel (Simrad EK500 operating at 38 and 120 kHz) and measured the density of krill along transect acoustically (g m-2 wet mass) prior to the ship's arrival. We hypothesised that if krill avoided the ship, perhaps in response to radiated noise, then the ship should detect less krill than the AUV which is known to have much lower noise levels than the ship. We were unable to detect any significant difference between the density of krill detected by the ship or the AUV, either at the transect level or at finer scales within transects. We conclude, therefore, that avoidance by krill of RRS James Clark Ross will not significantly bias acoustic estimates of krill abundance by this vessel