Hosts use altered macronutrient intake to circumvent parasite-induced reduction in fecundity

Explanations for the evolution of pathogen-induced fecundity reduction usually rely on a common principle: the trade-off between host longevity and reproduction. Recent advances in nutritional research have, however, challenged this assumption and shown that longevity and reproduction are not inextricably linked. In this study, we showed that beetles infected by cysticercoids of the tapeworm Hymenolepis diminuta increased their total food intake and, more particularly, their carbohydrate consumption compared with uninfected insects. This increased intake was only pronounced during the first 12 days p.i., when the parasite grows and develops into a mature metacestode. Despite consuming more nutrients, infected individuals sustained lower levels of body lipid and were less efficient at converting ingested protein to body protein. However they demonstrated a capacity to compose a diet that sustained high levels of reproductive output unless confined to foods that were nutritionally dilute. We did not find any indication that macronutrient intakes had an effect on host pro-phenoloxidase activity; however, phenoloxidase activity was significantly affected by protein intake. Our results showed that when offered nutritionally complementary diets, infected hosts do not systematically suffer a reduction in fecundity. Thus, in our view, the assumption that a reduction in host reproduction represents an adaptive response by the host or the parasite to divert resources away from reproduction toward other traits should be reassessed.     

Impact of a multimodal exercise program on tibial bone health in adolescents with Development Coordination Disorder: an examination of feasibility and potential efficacy

Objectives:Developmental coordination disorder (DCD) compromises bone health purportedly due to lower levels of physical activity. The potential of an exercise intervention to improve bone health parameters in adolescents with DCD has not previously been studied. This study thus aimed to determine the impact of a multimodal exercise intervention on bone health in this population at-risk of secondary osteoporosis.Methods:Twenty-eight adolescents (17 male, 11 female) aged between 12-17 years (M_age=14.1) with DCD participated in a twice weekly, 13-week generalised multimodal exercise intervention. Peripheral quantitative computed tomography scans of the tibia (4% and 66%) were performed over a six month period. Generalised estimating equations were used to examine the impact of fitness measures on bone parameters over time.Results:An overall improvement trend was observed for bone health, with significant increases at the 66% tibial site for bone mass (4.12% increase, d_cohen=0.23, p=0.010) and cortical area (5.42% increase, η² =12.09, p=0.014). Lower body fitness measures were significantly associated with improvements in bone health parameters, tempered by the degree of motor impairment.Conclusion:A multimodal exercise intervention may be effective in improving bone health of adolescents with DCD. Given the impact of motor impairments, gains may be greater over an extended period of study.     

The COVID‐19 pandemic: agile versus blundering communication during a worldwide crisis: Important lessons for efficient communication to maintain public trust and ensure public safety

Governments’ measures to control the COVID‐19 pandemic and public reaction hold important lessons for science and risk communication in times of crisis.

The world is in the grips of a global pandemic, the end of which is not yet in sight. Nations struggle to deal with the severe health, economic and social impacts of COVID‐19 with varying success. Their ability to handle this crisis depends on many factors, some of which, such as the availability of vaccines, are variable, while others – geographical location or population density – are determined. More importantly though, public health infrastructures, political will and action, and clear communication have so far proved to be the most successful levers for coping with the pandemic. This article examines how political will and communication in particular have helped to alleviate the impact of the virus in some countries.

… public health infrastructures, political will and action, and clear communication have so far proved to be the most successful levers for coping with the pandemic.

News that a new virus had emerged in Wuhan, China, was just of fleeting interest for most people in December 2019. This changed rapidly: by March 2020, large parts of the world had gone into lockdown to curtail the rapid spread of SARS‐CoV‐2. Many governments issued more or less harsh restrictions on private contacts, travel and other freedoms, followed by easing these regulations during the summer, which precipitated new outbreaks in the fall along with mutations of the virus that triggered new restrictions; it is likely that this pattern will continue until a sufficient number of people are vaccinated to achieve herd immunity.COVID‐19 came “out of the blue”, hit a largely unprepared human population and has therefore affected human civilisation in an unprecedented manner (Fig 1). People are not only concerned about their health: as the pandemic continues, citizens also worry about the social, economic and psychological impacts. Even though vaccination programmes are under way, only a few countries will be able to achieve herd immunity by the summer; in the meantime, public acceptance for the ongoing restrictions of freedom are waning as the negative social and economic effects become more urgent. Thus, political action and planning along with efficient communication in particular are crucially important to ensure the public’s understanding of the situation and maintain acceptance for restrictive measure until enough vaccines become available. The antipodes in communication strategies were a mixture of evidence‐based messages, transparency, building confidence and open discussion of scientific uncertainty to gain and maintain public trust versus the unfettered spread of alternative facts, targeted disinformation and omission of important information that eventually eroded said trust.Open in a separate windowFigure 1Fear in times of COVID‐19An elderly pedestrian wearing a face mask due to the COVID‐19 pandemic, walks past graffiti depicting the subjects within famous artworks, in Glasgow on 2 September 2020 after the Scottish government imposed fresh restrictions on the city after a rise in cases of the novel coronavirus (© Andy Buchanan/AFP via Getty Images)

… political action and planning along with efficient communication in particular are crucially important to ensure the public’s understanding of the situation and maintain acceptance for restrictive measure…

     

Dark CO2 fixation into phospholipid-derived fatty acids by the cold-water coral associated sponge Hymedesmia (Stylopus) coriacea (Tisler Reef,NE Skagerrak)

ABSTRACT

Many cold-water sponges harbour microorganisms of which the role in the sponge host remains enigmatic. Here, we show a transfer of fixed inorganic carbon by sponge-associated microbes to its host, the cold-water coral encrusting sponge Hymedesmia (Stylopus) coriacea. Sponge were collected at approx. 100?m depth and incubated for 1.5–2.5 days with ¹³C labelled dissolved inorganic carbon (DIC) as tracer. Total DIC fixation rates ranged from 0.03–0.11?mmol C?×?mmol C_sponge × d^?1. ¹³C-tracer was recovered in bacterial-specific (i.e. short and branched) and sponge-specific (very long-chained) phospholipid-derived fatty acids (PLFA's), but was not incorporated into archaeal lipids. ¹³C-incorporation in biomarkers such as C16:1w7c and C18:1w7c indicated that nitrifying and/or sulphur-oxidizing bacteria (chemoautotrophs) were likely active in the sponge. Trophic transfer of microbially-fixed carbon to the sponge host was confirmed by recovery of label in very long chain fatty acids (VLCFA's) including C26:2 and C26:3. Tracer accumulation into several VLCFA's continued after removal of ¹³C-DIC, while tracer in most bacteria-specific PLFA's declined, indicating a transfer and elongation of bacterial-specific PLFA's to sponge-specific PLFA's. This implies that PLFA precursors released from chemo- as well as heterotrophic microbes in sponges contributed to the synthesis of VLCFA's, identifying sponge-associated bacteria as symbionts of the sponge.     

ACTH accelerates recovery of neuromuscular function following crushing of peripheral nerve

Adrenocorticotropin (ACTH)-treated adrenalectomized rats subjected to crush denervation recover sensation and functional movement sooner than saline-treated rats. Axonal regeneration is accelerated, the number of large endplates and the frequency of preterminal branching are increased. ACTH has no effect on either intact or denervated muscles. The ameliorative action of ACTH during regeneration is apparently neurogenic and independent of corticoids.