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Objective: We aimed to investigate prospective associations between milk bioactives related to metabolic health (glucose, insulin, leptin, C reactive protein [CRP], and interleukin 6 [IL-6]) and incident formula initiation at 3 and 6 months postpartum. Design: This study included 363 mother–infant dyads who were fully breastfed at 1 month and participated in the prospective Mothers and Infants Linked for Healthy Growth study from pregnancy to 6 months postpartum. Associations between milk glucose, leptin, insulin, CRP, and IL-6 at 1 and 3 months and incident formula feeding (FF) at 3 and 6 months, respectively, were tested using multiple logistic regression, adjusting for numerous potential confounders such as maternal age and prepregnancy body mass index. Results: At 3 months postpartum, 1-month glucose (odds ratio [OR] 0.45 [95% confidence interval (CI): 0.27–0.75], p ≤ 0.01) and smaller decreases in glucose from 1 to 3 months (OR 0.51 [95% CI: 0.28–0.92], p = 0.03) were associated with lower odds of FF, whereas 1-month leptin (OR 2.30 [95% CI: 1.30–4.07], p

Anthropogenic carbon emissions released into the atmosphere is driving rapid, concurrent increases in temperature and acidity across the world's oceans. Disentangling the interactive effects of warming and acidification on vulnerable life stages is important to our understanding of responses of marine species to climate change. This study evaluates the interactive effects of these stressors on the acute response of gene expression of postlarval American lobster (Homarus americanus), a species whose geographic range is warming and acidifying faster than most of the world's oceans. In the context of our experiment, we found two especially noteworthy results: First, although physiological end points have consistently been shown to be more responsive to warming in similar experimental designs, our study found gene regulation to be considerably more responsive to elevated pCO2. Furthermore, the combined effect of both stressors on gene regulation was significantly greater than either stressor alone. Using a full factorial experimental design, lobsters were raised in control and elevated pCO2 concentrations (400 ppm and 1,200 ppm) and temperatures (16°C and 19°C). A transcriptome was assembled from an identified 414,517 unique transcripts. Overall, 1,108 transcripts were differentially expressed across treatments, several of which were related to stress response and shell formation. When temperature alone was elevated (19°C), larvae downregulated genes related to cuticle development; when pCO2 alone was elevated (1,200 ppm), larvae upregulated chitinase as well as genes related to stress response and immune function. The joint effects of end‐century stressors (19°C, 1,200 ppm) resulted in the upregulation of those same genes, as well as cellulase, the downregulation of calcified cuticle proteins, and a greater upregulation of genes related to immune response and function. These results indicate that changes in gene expression in larval lobster provide a mechanism to respond to stressors resulting from a rapidly changing environment., Using nextgen transcriptomic sequencing methodologies, our study evaluates the single and joint effects of elevated temperature and CO2 on gene regulation in the postlarval stage of the American lobster. Our study shows gene regulatory response to be considerably more affected by elevated pCO2 levels than elevated temperature, contrasting what has been shown in studies of physiological end points of larval crustaceans, as well as a strong joint effect of simultaneous stressors.

Changes in temperature alter the viscosity of fluids, which impacts the force needed to move and the diffusion rates of gases. This is particularly salient for organisms that operate at mid to low Reynolds numbers. In this study, we investigated the independent effects of changes in temperature and viscosity on oxygen consumption rates of two coastal copepods (

Hydrogen peroxide (H2O2), a pesticide used in salmonid aquaculture, is released directly into the environment where nontarget organisms are at risk of exposure. We determined threshold concentrations for mortality of Calanus spp., the dominant zooplankton species in the North Atlantic, and assessed sublethal effects, focusing on the escape response and oxygen consumption rates (OCRs) as behavioral and physiological assays. One-hour exposure to 170 mg·L−1 (i.e., 10% of the recommended H2O2 treatment) was lethal to copepodite stage V (92% mortality) and adult females (100% mortality). The acute median lethal concentration (1h-LC50) was 214.1 (150.67–277.4) and 48.6 (44.9–52.2) mg·L−1 for copepodite V and adults, respectively. The 25-h LC50 was 77.1 (57.9–96.2) and 30.63 (25.4–35.8) mg·L−1 for copepodite V and adults, respectively. At concentrations of 0.5% and 1% of the recommended treatment level, Calanus spp. showed a decrease in escape performance and lower OCRs with increased concentration. At H2O2 concentrations of 5% of the recommended treatment levels (85 mg·L−1), exposed copepods showed no escape reaction response. These results suggest that sublethal concentrations of H2O2 will increase the risk of predation for Calanus spp. Furthermore, this study provides supporting evidence that theoretical “safe” values, traditionally used for predicting toxicity thresholds, underestimate the impact of H2O2 on the physiological condition of nontarget crustaceans.

Seismic surveys use airguns that emit low frequency high magnitude sound to detect subsea resources and to map seabed geology. The effect of seismic blasts on Calanus spp., a key food source for commercially important fish, was assessed in field experiments. Immediate mortality of copepods was significantly different from controls at distances of 5 m or less from the airguns. Mortality 1 week after the airgun blast was significantly higher—by 9% relative to controls—in the copepods placed 10 m from the airgun blast but was not significantly different from the controls at a distance of 20 m from the airgun blast. The increase in mortality—relative to controls—did not exceed 30% at any distance from the airgun blast. Only two genes changed in response to the airgun blast; however, their function is unknown. There were no sublethal effects of the seismic blasts on the escape performance or the sensory threshold needed to initiate an escape response at any of the distances from the airgun blast that were tested. Results from these experiments suggest that seismic blasts have limited effects on the mortality or escape response of Calanus sp. within 10 m of the blast and no measurable impact at greater distances.

Microplastic fibers (MPF) are a ubiquitous marine contaminant, making up to 90% of global microplastic concentrations. Imaging flow cytometry was used to measure uptake and ingestion rates of MPF by blue mussels (Mytilus edulis). Mussels were fed a diet of Rhodomonas salina and MPF concentrations up to 30 MPF mL−1, or 0.374% of available seston. Filtration rates were greatly reduced in mussels exposed to MPF. Uptake of MPF followed a Holling's Type II functional response with 95% of the maximum rate (5227 MPF h−1) occurring at 13 MPF mL−1. An average of 39 MPF (SE ± 15, n = 4) was found in feces (maximum of 70 MPF). Most MPF (71%) were quickly rejected as pseudofeces, with approximately 9% ingested and

Characterizing the capacity of marine organisms to adapt to climate change related drivers (e.g., pCO2 and temperature), and the possible rate of this adaptation, is required to assess their resilience (or lack thereof) to these drivers. Several studies have hypothesized that epigenetic markers such as DNA methylation, histone modifications and noncoding RNAs, act as drivers of adaptation in marine organisms, especially corals. However, this hypothesis has not been tested in zooplankton, a keystone organism in marine food webs. The objective of this study is to test the hypothesis that acute ocean acidification (OA) exposure alters DNA methylation in two zooplanktonic species—copepods (Acartia clausii) and cladocerans (Evadne nordmanii). We exposed these two species to near‐future OA conditions (400 and 900 ppm pCO2) for 24 h and assessed transcriptional and DNA methylation patterns using RNA sequencing and Reduced Representation Bisulfite Sequencing (RRBS). OA exposure caused differential expression of genes associated with energy metabolism, cytoskeletal and extracellular matrix functions, hypoxia and one‐carbon metabolism. Similarly, OA exposure also caused altered DNA methylation patterns in both species but the effect of these changes on gene expression and physiological effects remains to be determined. The results from this study form the basis for studies investigating the potential role of epigenetic mechanisms in OA induced phenotypic plasticity and/or adaptive responses in zooplanktonic organisms., Characterizing the capacity of marine organisms to adapt to climate‐change‐related drivers (e.g. pCO2 and temperature), and the possible rate of this adaptation, is required to assess their resilience (or lack thereof) to these drivers. In an effort to understand these, we conducted a study investigating the potential epigenetic changes in response to Ocean acidification in two planktonic species of ecological importance (Copepod, Acartia clausi and Cladoceran, Evadne nordmanni). Our results suggest that these organisms can employ epigenetic mechanisms in coping with acute changes in pCO2 levels. Future research will characterize long‐term adaptive responses to climatic factors such as pCO2 and temperature.

Accelerated postnatal growth is a potentially modifiable risk factor for future obesity. To study how specific breast milk components contribute to early growth and obesity risk, we quantified one-carbon metabolism-related metabolites in human breast milk and found an inverse association between milk betaine content and infant growth. This association was replicated in an independent and geographically distinct cohort. To determine the potential role of milk betaine in modulating offspring obesity risk, we performed maternal betaine supplementation experiments in mice. Higher betaine intake during lactation increased milk betaine content in dams and led to lower adiposity and improved glucose homeostasis throughout adulthood in mouse offspring. These effects were accompanied by a transient increase in Akkermansia spp. abundance in the gut during early life and a long-lasting increase in intestinal goblet cell number. The link between breast milk betaine and Akkermansia abundance in the gut was also observed in humans, as infants exposed to higher milk betaine content during breastfeeding showed higher fecal Akkermansia muciniphila abundance. Furthermore, administration of A. muciniphila to mouse pups during the lactation period partially replicated the effects of maternal breast milk betaine, including increased intestinal goblet cell number, lower adiposity, and improved glucose homeostasis during adulthood. These data demonstrate a link between breast milk betaine content and long-term metabolic health of offspring., This work was supported by grants from Ajinomoto Innovation Alliance Program (Ajinomoto 2015-2017) to CL, EFSD/Lilly programme to C.L., and the Spanish Government (SAF-2017-88005-R to C.L. and BFU2017-89336-R to M.V.). D.S.-I. and J.C.J.-C. are Miguel Servet investigators (Carlos III National Institute of Health, Spain). The MILK Study is supported by NIH grant R01-HD080444 to D.A.F. and E.W.D. Mead Johnson Nutrition provided financial support to D.A.F. for breast milk collection, but had no role in study design, study results, or manuscript content. M.C.C. and I.G.-M. acknowledge support from European Research Council under the European Union’s Horizon 2020 research and innovation programme (ERC Starting Grant 639226).

Purpose of review This narrative review presents the current state of available evidence regarding the role of breast milk carbohydrates on infant outcomes, with a primary focus on growth and body composition. Recent findings To date, there is a paucity of available data that exists in this realm. The current literature focuses on the role of two carbohydrate fractions in breast milk, and their relationships with infant outcomes in the first six months of life: oligosaccharides and fructose. A small but growing body of research indicates robust associations of both oligosaccharides and fructose in breast milk with infant weight and length, as well as bone, fat, and lean mass. There is also emerging evidence to support the role of these same carbohydrate fractions in breast milk in infant cognitive development. Summary The present state of the science suggests that oligosaccharides and fructose in breast milk play a role in infant growth and body composition and introduces intriguing associations of these two carbohydrate fractions with infant cognitive development as well.

The salmon louse (Lepeophtheirus salmonis [Krøyer]) is an ectoparasitic copepod that causes disease in farmed Atlantic salmon (Salmo salar) and may play a role in the decline of some wild salmonid populations. Controlling lice infestations is a major cost for the salmon industry; this has stimulated the pursuit of alternative approaches to controlling them. One such approach involves determining, and then disrupting, the sensory cues used by the parasite to find its host. In this context, we examined the behavioural responses of lice copepodids to light flicker-simulating light reflecting from the sides of the salmon host and/or the shadows cast by fish passing overhead-and water-soluble chemicals released from the skin of the salmon. From these observations, we estimate that visual cues such as those presented here would operate at relatively long range (metres to tens of metres). A diffuse host-related olfactory cue stimulated swimming, however, it remains unclear whether olfactory cues provide directional information. The observations presented herein could be used to disrupt the link between the parasite and host fish, using a large number of traps deployed at a distance from a salmon farm, for example, thereby reducing sea lice infestation pressure.

Source at http://dx.doi.org/10.1002/ece3.3063 . Ocean acidification is the increase in seawater pCO2 due to the uptake of atmospheric anthropogenic CO2, with the largest changes predicted to occur in the Arctic seas. For some marine organisms, this change in pCO2, and associated decrease in pH, represents a climate change-related stressor. In this study, we investigated the gene expression patterns of nauplii of the Arctic copepod Calanus glacialis cultured at low pH levels. We have previously shown that organismal-level performance (development, growth, respiration) of C. glacialis nauplii is unaffected by low pH. Here, we investigated the molecular-level response to lowered pH in order to elucidate the physiological processes involved in this tolerance. Nauplii from wild-caught C. glacialis were cultured at four pH levels (8.05, 7.9, 7.7, 7.5). At stage N6, mRNA was extracted and sequenced using RNA-seq. The physiological functionality of the proteins identified was categorized using Gene Ontology and KEGG pathways. We found that the expression of 151 contigs varied significantly with pH on a continuous scale (93% downregulated with decreasing pH). Gene set enrichment analysis revealed that, of the processes downregulated, many were components of the universal cellular stress response, including DNA repair, redox regulation, protein folding, and proteolysis. Sodium:proton antiporters were among the processes significantly upregulated, indicating that these ion pumps were involved in maintaining cellular pH homeostasis. C. glacialis significantly alters its gene expression at low pH, although they maintain normal larval development. Understanding what confers tolerance to some species will support our ability to predict the effects of future ocean acidification on marine organisms.

The copepod Lepeophtheirus salmonis is an obligate ectoparasite of salmonids. Salmon lice are major pests in salmon aquaculture and due to its economic impact Lepeophtheirus salmonis is one of the most well studied species of marine parasite. However, there is limited understanding of how increased concentration of pCO2 associated with ocean acidification will impact host-parasite relationships. We investigated the effects of increased pCO2 on growth and metabolic rates in the planktonic stages, rearing L. salmonis from eggs to 12 days post hatch copepodids under three treatment levels: Control (416 µatm), Mid (747 µatm), and High (942 µatm). The pCO2 treatment had a significant effect on oxygen consumption rate with the High treatment animals exhibiting the greatest respiration. The treatments did not have a significant effect on the other biological endpoints measured (carbon, nitrogen, lipid volume, and fatty acid content). The results indicate that L. salmonis have mechanisms to compensate for increased concentration of pCO2and that populations will be tolerant of projected future ocean acidification scenarios. The work reported here also describes catabolism during the lecithotrophic development of L. salmonis, information that is not currently available to parameterize models of dispersal and viability of the planktonic free-living stages.

Few studies have evaluated the joint effects of elevated temperature and pCO2 on marine organisms. In this study we investigated the interactive effects of Intergovernmental Panel on Climate Change predicted temperature and pCO2 for the end of the 21st century on key aspects of larval development of the American lobster, Homarus americanus, an otherwise well-studied, iconic, and commercially prominent species in the northeastern United States and Atlantic Canada. Our experiments showed that larvae (stages I–III) and postlarvae (stage IV) reared in the high temperature treatments (19 °C) experienced significantly lower survival, developed twice as fast, and had significantly higher oxygen consumption rates, than those in ambient treatments (16 °C). Larvae from the ambient temperature/high pCO2 (750 ppm) treatment had significantly longer carapace lengths, greater dry masses in stages I–III and higher C: N ratios in stage IV than larvae from all other treatments. Stage IVs raised in the high pCO2 treatment at 19 °C had significantly higher feeding rates and swimming speeds than stage IVs from the other three treatments. Together these results suggest that projected end-century warming will have greater adverse effects than increased pCO2 on larval survival, and changing pCO2 may have a complex effect on larval metabolism and behaviour. Understanding how the most vulnerable life stages of the lobster life cycle respond to climate change is essential in connecting the northward geographic shifts projected by habitat quality models, and the underlying physiological and genetic mechanisms that drive their ecology.

As the world's oceans continue to absorb anthropogenic CO2 from the atmosphere, the carbonate chemistry of seawater will change. This process, termed ocean acidification, may affect the physiology of marine organisms. Arctic seas are expected to experience the greatest decreases in pH in the future, as changing sea ice dynamics and naturally cold, brackish water, will accelerate ocean acidification. In this study, we investigated the effect of increased pCO2 on the early developmental stages of the key Arctic copepod Calanus glacialis. Eggs from wild-caught C. glacialis females from Svalbard, Norway (80°N), were cultured for 2 months to copepodite stage C1 in 2°C seawater under four pCO2 treatments (320, 530, 800, and 1700 μatm). Developmental rate, dry weight, and carbon and nitrogen mass were measured every other day throughout the experiment, and oxygen consumption rate was measured at stages N3, N6, and C1. All endpoints were unaffected by pCO2 levels projected for the year 2300. These results indicate that naupliar development in wild populations of C. glacialis is unlikely to be detrimentally affected in a future high CO2 ocean.

The Subarctic copepod, Calanus finmarchicus, is an ecologically critical foundation species throughout the North Atlantic Ocean. Any change in the abundance and distribution of C. finmarchicus would have profound effects on North Atlantic pelagic ecosystems and the services that they support, particularly on the coastal shelves located at the southern margins of the species' range. We tested the hypothesis that the physiological rates and processes of C. finmarchicus, determining its vital rates, are unaffected by increases in CO2 concentration predicted to occur in the surface waters of the ocean during the next 100 years. We reared C. finmarchicus from eggs to adults at a control (580 µatm, the ambient concentration at the laboratory's seawater intake) and at predicted mid-range (1200 µatm) and high (1900 µatm) pCO2. There was no significant effect of pCO2 on development times, lipid accumulation, feeding rate, or metabolic rate. Small but significant treatment effects were found in body length and mass (in terms of dry, carbon and nitrogen mass), notably a somewhat larger body size at the mid-pCO2 treatment; that is, a putatively beneficial effect. Based on these results, and a review of other studies of Calanus, we conclude that the present parameterizations of vital rates in models of C. finmarchicus population dynamics, used to generate scenarios of abundance and distribution of this species under future conditions, do not require an “ocean acidification effect” adjustment. A review of research on planktonic copepods indicates that, with only a few exceptions, impacts of increased CO2 are small at the levels predicted to occur during the next century.

Chemoreception is critical for marine ectoparasites - such as salmon lice (Lepeophtheirus salmonis) - to identify and locate salmonid hosts. The molecular receptors that parasites employ to detect host-specific chemical stimuli from hosts (kairomones) have not been well characterised. In the present study, transcription of the sea louse Ionotropic receptor 25a (IR25a) was blocked to evaluate whether it functions as a chemical-perception related gene for a specific chemical cue from the Atlantic salmon host. Double-strand RNA interference (dsRNA) oligonucleotides were applied to salmon lice by in vitro transcription and then exposing salmon lice nauplii to dsRNA by soaking overnight. Silencing of the IR25a gene was confirmed by qPCR in experimental groups of knock-down copepodids (dsIR25a). Behavioural responses associated with host recognition were evaluated in dsIR25a sea lice after exposure to a peptide produced by the salmon host (Cath-2). The dsIR25a group decreased expression levels of IR25a by >7-fold with respect to the control group. This group was also 26% slower than the control group (control swimming speed was 69 mm/s, while the treated group was 51 mm/s). Since the swimming activity of salmon lice copepodids is associated with the activation of the chemosensory system, these results indicate that the L. salmonis chemosensory perception system was not fully activated due to gene silencing. The results of this study demonstrate the role of ionotropic receptor 25a during host recognition by sea lice.

Chemical signals are a key element of host-parasite interactions. In marine ecosystems, obligate ectoparasites, such as sea lice, use chemical cues and other sensory signals to increase the probability of encountering a host and to identify appropriate hosts on which they depend to complete their life cycle. The chemical compounds that underlie host identification by the sea lice are not fully described or characterized. Here, we report a novel compound - the Atlantic salmon (Salmo salar) antimicrobial peptide cathelicidin-2 (Cath-2) – that acts as an activation cue for the marine parasitic copepod Lepeophtheirus salmonis. L. salmonis were exposed to 0, 7, 70 and 700 ppb of Cath-2 and neural activity, swimming behaviour and gene expression profiles of animals in response to the peptide were evaluated. The neurophysiological, behavioural and transcriptomic results were consistent: L. salmonis detects Cath-2 as a water-soluble peptide released from the skin of salmon, triggering chemosensory neural activity associated with altered swimming behaviour of copepodids exposed to the peptide, and chemosensory-related genes were up-regulated in copepodids exposed to the peptide. L. salmonis are activated by Cath-2, indicating a tight link between this peptide and the salmon louse chemosensory system.

The most common biomineral produced in the contemporary ocean is calcium carbonate, including the polymorph calcite produced by coccolithophores. The surface waters of the ocean are supersaturated with respect to calcium carbonate. As a result, particulate inorganic carbon (PIC), such as calcite coccoliths, is not expected thermodynamically to dissolve in waters above the lysocline (~4500–6000 m). However, observations indicate that up to 60–80% of calcium carbonate is lost in the upper 500–1000 m of the ocean. This is hypothesized to occur in microenvironments with reduced saturation states, such as zooplankton guts. Using a new application of the highly precise 14C microdiffusion technique, we show that following a period of starvation, up to 38% of ingested calcite dissolves in copepod guts. After continued feeding, our data show the gut becomes increasingly buffered, which limits further dissolution; this has been termed the Tums hypothesis (after the drugstore remedy for stomach acid). As less calcite dissolves in the gut and is instead egested in fecal pellets, the fecal pellet sinking rates double, with corresponding increases in pellet density. Our results empirically demonstrate that zooplankton guts can facilitate calcite dissolution above the chemical lysocline, and that carbon export through fecal pellet production is variable, based on the feeding history of the copepod.

The coccolithophore Emiliania huxleyi forms some of the largest phytoplankton blooms in the ocean. The rapid demise of these blooms has been linked to viral infections. E. huxleyi abundance, distribution, and nutritional status make them an important food source for the heterotrophic protists which are classified as microzooplankton in marine food webs. In this study we investigated the fate of E. huxleyi (CCMP 374) infected with virus strain EhV-86 in a simple predator-prey interaction. The ingestion rates of Oxyrrhis marina were significantly lower (between 26.9 and 50.4%) when fed virus-infected E. huxleyi cells compared to non-infected cells. Despite the lower ingestion rates, O. marina showed significantly higher growth rates (between 30 and 91.3%) when fed infected E. huxleyi cells, suggesting higher nutritional value and/or greater assimilation of infected E. huxleyi cells. No significant differences were found in O. marina cell volumes or fatty acids profiles. These results show that virally infected E. huxleyi support higher growth rates of single celled heterotrophs and in addition to the “viral shunt” hypothesis, viral infections may also divert more carbon to mesozooplankton grazers.

Several dinoflagellate species in the genus Blastodinium are gut parasites of marine planktonic copepods. However,there is only limited information on the occurrence and infection frequencies of Blastodinium spp. in the field andalmost no information on the functional impact on their hosts. We report upon the effects of Blastodinium sp. infectionon Calanus finmarchicus from the northeastern Atlantic coast off southern Norway during April 2013 and 2014. Up to58% of C. finmarchicus were infected near the coast, while ,5% were infected several kilometers offshore. Ingestionrates of infected females were below detection limits and significantly lower than uninfected females. Blastodinium sp.-infected females showed characteristic symptoms of starvation, including lower respiration rates (implying a lowermetabolic rate), production of smaller and fewer fecal pellets and significantly fewer eggs than uninfected females. Afew females in this study were able to void the infection, however the extended period of starvation is likely to havelonger-term repercussions on egg production rates well after the copepod clears the infection. The degree to whichthe infection affects C. finmarchicus recruitment depends on the extent of the spatial distribution of the infection.Monitoring of parasitic infection during routine field surveys will be required in order to clarify this.KEYWORDS: zooplankton; secondary production; gut parasite; starvation; egg production; sterility; metabolism;ingestion; population dynamics; biogeochemical cycles

The micronutrient iron (Fe) is rapidly cycled in surface waters, and regenerated Fe supports much of the phytoplankton growth in open ocean waters. Meso- and microzooplankton grazing are both important mechanisms to regenerate Fe, but the chemical conditions in the respective digestive systems are different and might affect the bioavailability of Fe. We conducted radiotracer grazing experiments with the copepod Acartia tonsa or the heterotrophic dinoflagellate Oxyrrhis marina feeding on the diatom Thalassiosira pseudonana or the coccolithophore Emiliania huxleyi. Uptake of regenerated 55Fe by a separate T. pseudonana culture was compared to the uptake of inorganic Fe. Iron regenerated by A. tonsa was taken up 4- to 7-fold faster than inorganic iron. In contrast, no difference was detected between the uptake rate of inorganic Fe and Fe regenerated by O. marina. Ingestion of different prey by A. tonsa revealed that Fe released during diatom digestion was taken up 1.8-fold faster than Fe released from coccolithophore digestion. Digestive systems and the chemical makeup of the ingested prey are crucial in determining the bioavailability of regenerated Fe. Differences in pH and oxygen saturation between digestive vacuoles and guts may affect the speciation of regenerated Fe, and the release of ferrous Fe might contribute to the bioavailability of regenerated Fe. The ecological structure determines the importance of regenerated Fe for a particular ecosystem.

Body composition assessment provides a sharper picture of the human biological response to genetic and environmental influences than measures of body size and weight. Infant body composition is particularly important as a marker of fetal adaptation and developmental programming of subsequent health and disease, but until recently, the range of options for measuring infant body composition was relatively narrow. The purpose of this Toolkit: Methods in Human Biology review is to provide a comprehensive overview of methods of body composition methods currently used in infants 0 to 2 years of age, including anthropometric prediction equations, air displacement plethysmography (ADP), dual energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), isotope dilution, and magnetic resonance imaging (MRI). Information on the reliability, validity, and accuracy of the methods is provided. Unique aspects of infant physiology and behavior create challenges for body composition assessment, but this review provides guidance on suitable testing approaches and environments that may aid researchers in this important area of investigation.

Levels of ultraviolet-B radiation (UV-B: 280–315 nm) reaching the earth’s surface have increased over the past few decades due to ozone depletion. It is well documented that exposure to UV-B radiation increases mortality in marine fish larvae. However, few studies have examined sub-lethal effects of UV-B radiation such as, for example, the possibility that it affects prey consumption by fish larvae. Atlantic cod larvae were exposed to a sub-lethal level of ultraviolet-B radiation (UV-B: 280–315 nm) for 15 h. After the exposure, rotifers (4/mL) were fed to cod larvae at three different post-exposure intervals (20 min, 3 and 6 h). Trials were replicated three times for each post-exposure interval. The number of rotifers in the gut and the percent of empty guts (number of fish with empty gut/number of fish examined × 100) were analyzed. Results were compared to those of unexposed fish (the control treatment). UV-B exposed cod larvae had consumed significantly fewer rotifers than control fish at all post-exposure intervals. There was no significant difference in the frequency of empty guts between fish in the UV-B treatment versus fish in the control treatment at any of the post-exposure time points (although the difference at 20 min post-exposure was borderline significant). These observations suggest that cod larvae exposed to sub-lethal levels of UV-B have lower net energy gain which may lead to reduced growth rate and possibly poorer survival.

Paraeuchaeta norvegica (8.5 mm total length) and yolk-sac stage Atlantic cod larvae (4 mm total length) (Gadus morhua) larvae were observed in aquaria (3 l of water) using silhouette video photography. This allowed direct observations (and quantitative measurement) of predator–prey interactions between these two species in 3-dimensions. Tail beats, used by cod larvae to propel themselves through the viscous fluid environment, also generate signals detectable by mechanoreceptive copepod predators. When the prey is close enough for detection and successful capture (approximately half a body-length), the copepod launches an extremely rapid high Reynolds number attack, grabbing the larva around its midsection. While capture itself takes place in milliseconds, minutes are required to subdue and completely ingest a cod larva. The behavioural observations are used to estimate the hydrodynamic signal strength of the cod larva’s tail beats and the copepod’s perceptive field for larval fish prey. Cod larvae are more sensitive to fluid velocity than P. norvegica and also appear capable of distinguishing between the signal generated by a swimming and an attacking copepod. However, the copepod can lunge at much faster velocities than a yolk-sac cod larva can escape, leading to the larva’s capture. These observations can serve as input to the predator–prey component of ecosystem models intended to assess the impact of P. norvegica on cod larvae.

Type 1 diabetes (T1D) is a risk factor for cardiovascular disease. However, it is unclear whether increased body weight amplifies that risk in T1D patients. This is a cross-sectional study examining the presence of cardiovascular risk factors in normal and overweight children, both with and without T1D. Sixty-six children (aged 16±2.2 years) were included in one of the following groups: (T1D and normal weight, T1D and overweight, healthy and normal weight, and healthy and overweight). A fasting blood sample was analyzed for lipid profile (triglyceride, cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol), apolipoprotein B (apoB), and apolipoprotein C-III (apoC-III) levels. Body composition was determined by dual energy x-ray absorptiometry and vascular elasticity by HDI/Pulsewave CR-2000 (Hypertension Diagnostics, Eagan, MN). Statistical analyses examined the effect of T1D and body weight status and their interactions on cardiovascular risk parameters. In this study, the authors were unable to demonstrate an additive effect of body weight status and T1D on cardiovascular risk profile. However, subgroup analysis of patients with T1D revealed higher apoC-III levels in overweight patients with T1D (P=.0453) compared with normal-weight diabetic children. Most notably, there was a direct relationship of small artery elasticity to body weight status. This seemingly paradoxical observation supports recent data and warrants further investigation. J Clin Hypertens (Greenwich). 2011;13:351–356. ©2010 Wiley Periodicals, Inc.

Nearly all organisms show directional bias in sensitivity to environmental signals. In this study, the behavioral sensitivity of a common estuarine copepod, Acartia tonsa, varies significantly with respect to their orientation to a well-characterized fluid mechanical signal. Maximum sensitivity occurs at an angle of 25°–30° and lowest sensitivity occurs at angles of 60°–90° relative to the source. These results support the hypothesis that copepods are not uniformly sensitive to fluid signals and show directional bias in mechanosensitivity. The data also show that large copepods initiate their escape reaction further from the source than small copepods. There is, however, an uncharacteristically large increase in sensitivity at the transition between the nauplii and C1 stage despite being similar in size. This suggests that the mechanosensory system of the naupliar stages is less sensitive to fluid signals and helps to explain the higher predation rates experienced by nauplii.

Assessing hydration, that is, total body water (TBW) in adolescent athletes should be part of a comprehensive training program. However, there are no specific methods to assess TBW in young athletes. Moreover, the use of traditional techniques developed in healthy youths, based on a 2-compartment model, may yield inaccurate TBW estimates in young athletes. Therefore, the purpose of this study was to assess the accuracy of TBW non-reference field methods with a criterion method (i.e., deuterium dilution) in 118 adolescent athletes. Body volume was assessed by air displacement plethysmography, bone mineral was measured by dual-energy X-ray absorptiometry, and TBW by deuterium dilution. Non-reference TBW methods included 2 bioelectrical impedance analysis techniques (Tanita Body Composition Analyzer, model TBF-310) and bioelectrical impedance spectroscopy (BIS) (model 4000B); the Lohman's hydration constants of fat-free mass (FFM); and 3 derived anthropometric equations developed, respectively, by Kushner et al., Wells et al., and Morgenstern et al. The highest accuracy between TBW estimates and the reference model in both girls and boys was observed using the Lohman's constants (r2= 0.94, SEE = 1.56 kg; r2 = 0.92, SEE = 2.42 kg, respectively; p < 0.001), followed by both foot-to-foot Tanita (r2 = 0.88, SEE = 2.15 kg; r2 = 0.87, SEE = 3.01 kg, respectively; p < 0.001) and BIS (r2 = 0.92, SEE = 1.70 kg; r2 = 0.87, SEE = 3.04 kg, respectively; p < 0.001) with slopes and intercepts not significantly different from the line of identity. The regressions between anthropometric equations and the criterion method deviated from the line of identity (p < 0.05). The practical application of this study is that the specific constants of FFM hydration developed by Lohman seem to accurately estimate TBW in adolescent athletes. Foot-to-foot Tanita and BIS were also found to be valid and non-biased tools for predicting TBW. It would appear that the 3 anthropometric equations used are not appropriate for young athletes.

Plasma high density lipoprotein-cholesterol (HDL-C) concentrations negatively correlate with atherosclerotic cardiovascular disease. HDL is thought to have several atheroprotective functions, which are likely distinct from the epidemiological inverse relationship between HDL-C levels and risk. Specifically, strategies that reduce HDL-C while promoting reverse cholesterol transport (RCT) may have therapeutic value. The major product of the serum opacity factor (SOF) reaction versus HDL is a cholesteryl ester (CE)-rich microemulsion (CERM), which contains apo E and the CE of ∼400,000 HDL particles. Huh7 hepatocytes take up CE faster when delivered as CERM than as HDL, in part via the LDL-receptor (LDLR). Here we compared the final RCT step, hepatic uptake and subsequent intracellular processing to cholesterol and bile salts for radiolabeled HDL-, CERM- and LDL-CE by Huh7 cells and in vivo in C57BL/6J mice. In Huh7 cells, uptake from LDL was greater than from CERM (2-4×) and HDL (5-10×). Halftimes for [14C]CE hydrolysis were 3.0 ± 0.2, 4.4 ± 0.6 and 5.4 ± 0.7 h respectively for HDL, CERM and LDL-CE. The fraction of sterols secreted as bile acids was ∼50% by 8 h for all three particles. HDL, CERM and LDL-CE metabolism in mice showed efficient plasma clearance of CERM-CE, liver uptake and metabolism, and secretion as bile acids into the gall bladder. This work supports the therapeutic potential of the SOF reaction, which diverts HDL-CE to the LDLR, thereby increasing hepatic CE uptake, and sterol disposal as bile acids.

Summary 1. Using two- and three-dimensional video recordings, we examined the steps involved in predation that lead to the differential vulnerability of three sympatric rotifer sibling species (Brachionus plicatilis, B. ibericus and B. rotundiformis) to a co-occurring, predatory, calanoid copepod (Arctodiaptomus salinus). 2. Brachionus rotundiformis, the smallest prey tested, was the most vulnerable with the highest encounter rate, probability of attack, capture and ingestion, and the lowest handling time. 3. Comparison of our results with those of a previous study shows that A. salinus is a more efficient predator than a co-occurring cyclopoid copepod (Diacyclops bicuspidatus odessanus) feeding on these same rotifer species. However, despite its higher capture rates, A. salinus seems to be less selective than D. b. odessanus based on attack distances and prey handling times. 4. The differential vulnerability to both calanoid and cyclopoid copepod predation can help explain the coexistence and seasonal succession of these co-occurring rotifer species.

SUMMARY 1. Cyclopoid copepod predation on rotifers affects the dynamics and structure of zooplankton communities. We address the differential vulnerability of three sympatric rotifer sibling species belonging to the Brachionus plicatilis species complex. These co-occur with their cyclopoid predator, Diacyclops bicuspidatus odessanus. 2. Using video recording and tracking, we analysed the steps in predation including attack distance, attack angle, and rotifer species swimming in the presence and absence of the predator. Our results show the greater vulnerability of B. rotundiformis (the smallest species) to D. b. odessanus predation, which is associated with a high percentage of attacks after contact. Brachionus plicatilis (the biggest species) is the less vulnerable prey, with low percentage of attacks after contact and captures after attacks. Branchionus ibericus, the intermediate sized species, had also intermediate vulnerability. 3. The differential vulnerability provides insight into the coexistence and seasonal succession of these competing rotifer species. Our results show that the competitive superiority of B. rotundiformis may be balanced by its greater vulnerability to copepod predation.

This research provides the first reported thresholds for the behavioural response of an individual planktonic copepod. Using a novel technique to create near-field fluid disturbances, we directed microlitre volumes of water towards the antennulary setae. In response to an increasing strength of this purely mechanical signal, the animal varied its behaviour from a rapid flick to a capture response and finally an escape reaction. This work provides a basis for addressing the criteria copepods use to interpret biologically generated signals to elicit an appropriate behavioural response and offers insight into how these signals are differentiated from the random fluid motion in their environment.

This study investigated the physical and physiological response of individual setae on the antennule of Gaussia princeps. We found significant differences in the physical and physiological responses of the setae to various intensities of water flow. No physiological evidence was found to suggest that individual setae are dually innervated; however, directional bias in both the displace- ment and subsequent physiological responses was evident. Although more easily displaced by fluid flow, the shortest hairs were physiologically less sensitive to angular deflection than were the longer setae, so that slow flows produced a greater neural response in the long seta. The combination of high resistance to movement and acute physiological sensitivity allows the long seta to respond to biolog- ically driven, low-intensity flows while filtering out high-frequency background noise. This suggests that the most prominent, long, distal setae function as low-flow detectors whereas the short hairs respond to more rapid fluid motion. Each seta responds to only a portion of the overall range of water velocity in the copepod's habitat. Thus, the entire sensory appendage, which consists of an ensemble of setae of different morphologies and lengths, may function as a unit to code the intensity and direc- tionality of complex fluid disturbances.

Summary Purpose Bioelectrical impedance analysis (BIA) equations can predict total body water (TBW) and extracellular water (ECW) in non-athletic healthy populations. This study aimed: a) to develop BIA-based models for TBW and ECW prediction based on dilution methods in a sample of national level athletes; and b) to validate the new models with a cross-validation approach in a separate cohort using dilution methods as criterion. Methods Two hundred and eight highly trained athletes (21.3 ± 5.0 years) were evaluated during their respective competitive seasons. Athletes were randomly split into development (n = 139) and validation groups (n = 69). The criterion method for TBW was deuterium dilution and for ECW was bromide dilution, where ICW was the respective difference between both. Resistance (R) and reactance (Xc) were obtained with a phase-sensitive 50 kHz BIA device and used for the estimation of TBW and ECW. Results Athletic BIA-based models were developed for TBW and ECW [TBW = 0.286 + 0.195*S 2 /R + 0.385*Wt + 5.086*Sex; ECW = 1.579 + 0.055*S 2 /R + 0.127*Wt + 0.006*S 2 /Xc + 0.932*Sex, where sex is 0 if female or 1 if male, Wt is weight (kg), S is stature (cm), and R and Xc are in ohm (Ω)]. Cross validation revealed R 2 of 0.91 for TBW and R 2 0.70 for ECW and no mean bias. Conclusions The new equations can be considered valid, with no observed bias, thus affording practical means to quantify TBW and ECW in national level athletes.

Apolipoprotein F (ApoF) is a sialoglycoprotein that is a component of the HDL and LDL fractions of human serum. We sought to test the hypothesis that ApoF plays an important role in atherosclerosis in mice by modulating lipoprotein function. Atherosclerosis was assessed in male low density lipoprotein receptor knockout (Ldlr KO) and ApoF/Ldlr double knockout (DKO) mice fed a Western diet for 16 weeks. ApoF/Ldlr DKO mice showed a 39% reduction in lesional area by en face analysis of aortas (p < 0.05), despite no significant differences in plasma lipid parameters. ApoF KO mice had reduced expression of Interferon alpha (IFNα) responsive genes in liver and spleen, as well as impaired macrophage activation. Interferon alpha induced gene 27 like 2a (Ifi27l2a), Oligoadenylate synthetases 2 and 3 (Oas2 and Oas3) were significantly reduced in the ApoF KO mice relative to wild type controls. These effects were attributable to hypomorphic expression of Stat2 in the ApoF KO mice, a critical gene in the Type I IFN pathway that is situated just 425 base pairs downstream of ApoF. These studies implicate STAT2 as a potentially important player in atherosclerosis, and support the growing evidence that the Type I IFN pathway may contribute to this complex disease.

The cyclopoid copepod Oithona was found to exhibit multiple escape reactions when entrained within quantified flow fields. The distance of the escape from the flow‐producing predator mimic (a siphon) decreased with a concurrent decrease in escape distance and speed. Although individuals became behaviorally more sensitive to fluid motion with each successive escape reaction, the lower thresholds were not manifested as more distant escape reactions. Overall, the escape distance and speed decreased significantly with decreased signal strength. The decrease may result from the high cost of the escape reaction, which was calculated to account for 36% of the normal metabolic rate and 500 times the cost of normal swimming.

Daphnids with higher density than the surrounding water body have to push water downwards to hold their position in the water column. This swimming current is mainly the result of the movement of the second antennae and only to a small extent due to the filter current. The water structures under the Daphnia are very variable depending on the swimming behavior. We focused on the hop and sink behavior, where the downward-pushed water masses form a wake which can be described as a mushroom-shaped vortex. The volume of this structure increases linearly with time. The wake volume is much larger than the zooplankton itself which can be important for the percep- tibility by mechanically sensing carnivorous predators. In water with a density gradient of 10 kg m -4 the wake length WL can be described by WL = 1.64 (± 0.096) 3 L 1.58 (± 0.14) with the length of the Daphnia L in millimeters. The wake length, measured after 5 s, remained constant for gradients up to 1 kg m-4. Above this value, the wake length declines in good agreement with the value expected from theory with WL = 10.66 (± 0.21) 3 (dr/dz)-0.265 (± 0.010). Since the intra- and inter-specific 'communication' (e.g. mate seeking, nutrient partition between phytoplankton and bacteria, predator avoidance) can be expected to be bound to the hydrodynamic properties of the wakes, different wake forms and sizes most likely have an important impact on the information sent out.

The small-scale spatial and temporal dynamics of phycosphere-sized chemical signals entrained within the feeding current of copepods is quantified here by combining flow visualization techniques with electrochemical technology (IVEC-10). Using the 30-mm electrochemical probe sampling at 50 Hz and the velocity gradients created by two marine copepods, we evaluated how odor deformation improves the potential for remote chemoreception. Our data show that when shear is strong, as found in the feeding current of an omnivore, Pleuromamma xiphias,elongation of the chemical signal is greater than that found for an odor signal entrained in the low-shear feeding current of a carnivore, Euchaeta rimana. Furthermore, within the feeding current of a single species, E. rimana, certain areas provided greater potential for remote chemoreception. These results support the hypotheses that chemical signals are deformed by the feeding current and that the feeding current structure enhances signal detection. The deformation of the odor field within the laminar feeding current provides a leading edge that gives a chemosensitive copepod early warning of an approaching odor source. By sensing the leading edge, a copepod could have a few hundred milliseconds to reorient itself with respect to the odor source. Advance warning improves the probability of successful behavior in response to signal sources such as prey, predators, and mates.

The threshold shear values needed to elicit the escape reaction to a quantifiable fluid mechanical disturbance were compared between five free-swimming oceanic copepod species. The results indicate a significant difference in the threshold for different species of copepods and between different age groups within a single species. In general, animals captured from more energetic regimes required a higher threshold than those captured from more pacific locations. Labidocera madurae required the highest shear values with 51.5 s~' for 50% of the animals tested to elicit an escape reac- tion (5jo). Acartia tonsa and Euchaeta rimana, in contrast, were behaviorally the most sensitive requir- ing an 550 of only 1.5 and 4.1 s~', respectively, to initiate an escape reaction. Pleuromamma xiphias and Oithona required intermediate shear values with an 550 of 7.2 and 8.1 s~'. When compared to literature values, the threshold needed to elicit an escape reaction was consistently higher than average environmental shear values. Threshold shear values also varied significantly with develop- mental stage. Naupliar stages of A.tonsa required greater than six times the 550 value required by adults of the same species. This suggests that the higher vulnerability to predation of naupliar stages of copepods may not only reflect inferior escape strength, but may also result from the higher thresh- old needed to elicit an escape reaction. This study supports the hypothesis that selective feeding pat- terns exhibited by predators of copepods may be the result of the differential behavioral sensitivities of different species and developmental stages of copepods.

This study compared the growth of healthy infants fed a hypoallergenic 100% whey-based extensively hydrolyzed formula (EHF) with Bifidobacterium lactis (test) with that of infants fed an extensively hydrolyzed casein formula (control). Formula-fed infants (14 ± 3 days) were randomized to test or control groups until 112 days of age. Anthropometrics were assessed at 14, 28, 56, 84, and 112 days, and daily records were kept for 2 days prior to study visits. Serum albumin and plasma amino acids at 84 days were assessed in a subset. A total of 282 infants were randomized (124 test, 158 control). Significantly more infants dropped out of the control (56%) as compared with the test (41%) group. Mean daily weight gain was significantly higher in the test group compared with the control group (27.95 ± 5.91 vs 25.93 ± 6.12 g/d; P = .027) with the test group reporting significantly fewer stools (2.2 vs 3.6 stools/d; P < .0001). The control group reported significantly more days with >3 loose stools/d and a higher incidence of vomiting as compared with the test group. There were no differences in gas, mood, sleep, or serum albumin. Plasma arginine and valine were significantly lower in the test group, whereas leucine and lysine were higher; all values were within normal limits. Significantly more adverse events attributed to the study formula were reported in the control group. The 100% whey-based hypoallergenic EHF containing Bifidobacterium lactis and medium chain triglycerides supported growth of healthy infants. Future studies on the application of this formula in clinically indicated populations are warranted.

Apolipoprotein F (apoF) is 29 kilodalton secreted sialoglycoprotein that resides on the HDL and LDL fractions of human plasma. Human ApoF is also known as Lipid Transfer Inhibitor protein (LTIP) based on its ability to inhibit cholesteryl ester transfer protein (CETP)-mediated transfer events between lipoproteins. In contrast to other apolipoproteins, ApoF is predicted to lack strong amphipathic alpha helices and its true physiological function remains unknown. We previously showed that overexpression of Apolipoprotein F in mice reduced HDL cholesterol levels by 20–25% by accelerating clearance from the circulation. In order to investigate the effect of physiological levels of ApoF expression on HDL cholesterol metabolism, we generated ApoF deficient mice. Unexpectedly, deletion of ApoF had no substantial impact on plasma lipid concentrations, HDL size, lipid or protein composition. Sex-specific differences were observed in hepatic cholesterol content as well as serum cholesterol efflux capacity. Female ApoF KO mice had increased liver cholesteryl ester content relative to wild type controls on a chow diet (KO: 3.4+/−0.9 mg/dl vs. WT: 1.2+/−0.3 mg/dl, p

Among judo athletes, strong grip strength is crucial for performing offensive and defensive maneuvers that rely predominantly on forearm maximal strength (FMS). The study aims were to evaluate changes in total-body water (TBW) and its compartments (extracellular water [ECW] and intracellular water [ICW]) and their relationship with loss of FMS in elite judo athletes. At baseline (weight stability), 27 male elite athletes were evaluated (age: 23.2 ± 2.8 years) and again evaluated 1-3 days before competition. Athletes were free to gain or lose weight based upon their specific competition needs. Using dilution techniques (deuterium and bromide), TBW and ECW were estimated, and ICW was calculated (ICW = TBW - ECW). Fat, fat-free mass, and appendicular lean soft tissue (LST) were assessed by dual-energy x-ray absorptiometry. Handgrip was used to assess FMS. Using a reduction of 2% as a representative outcome for decreased FMS, 10 athletes were identified as having lost FMS, whereas 17 changed2% or gained. Comparison of means and logistic regression analysis were performed. Results from baseline to before competition indicated that those who lost ≥2% of FMS significantly decreased TBW and ICW by -2.7 ± 3.0 and -4.4 ± 4.2%, respectively. The groups differed in ICW changes (-4.4 ± 4.2 vs. 1.9 ± 6.1%), respectively, for those who lost FMS by ≥2%. The ICW changes, but not in TBW or ECW, significantly predicted the risk of losing FMS (β = 0.206; p = 0.027), even adjusting for weight and arm LST changes. These findings indicated that reductions in ICW increased the risk of losing grip strength in elite judo athletes.

In the north Atlantic, Meganyctiphanes norvegica feeds predominantly on copepods, including Calanus spp. To quantify its perceptual field for prey, and the sensory systems underlying prey detection, the responses of tethered krill to free-swimming Calanus spp. were observed in 3D using silhouette video imaging. An attack–which occurred despite the krill’s being tethered—was characterized by a pronounced movement of the krill’s antennae towards the target, followed by a propulsion and opening of the feeding basket. Frequency distributions of prey detection distances were significantly different in the light vs. the dark, with median values of 26.5 mm and 19.5 mm, respectively. There were no significant differences in the angles at which prey were detected by krill (relative to the predator’s longitudinal body axis) in the light vs. the dark. Prey detections were symmetrically distributed on either side of the predator, in both light and dark. However, significant asymmetry was found in the dorsal–ventral direction with 80% of the prey detections located below the midline of the krill’s body axis and, given the placement and orientation of the compound eyes, presumably outside its visual field of view. This indicates that, at least under these conditions, vision was not the main sensory modality involved in the detection of active prey by M. norvegica. However, under some circumstances, vision may provide supplemental information. Avoidance responses of copepod prey were nearly twice the velocity of their nominal background swimming speed (153 ± 48 and 85 ± 75 mm s−1, respectively), on average taking them 43 ± 16 mm away from the predator. This is far beyond the krill’s perceptual range, suggesting that the escape reaction provides an effective deterrent to predation (although perhaps less so for free-swimming krill). This information can be used to parameterize models that assess the role of krill as predators in marine ecosystems. Electronic supplementary material The online version of this article (doi:10.1007/s00227-010-1405-9) contains supplementary material, which is available to authorized users.

This study was designed to assess the usefulness of skinfold (SKF) equations developed by Jackson and Pollock (JP) and by Evans (Ev) in tracking body composition changes (relative fat mass [%FM], absolute fat mass [FM], and fat-free mass [FFM]) of elite male judo athletes before a competition using a 4-compartment (4C) model as the reference method. A total of 18 male, top-level (age: 22.6 +/- 2.9 yr) athletes were evaluated at baseline (weight: 73.4 +/- 7.9 kg; %FM4C: 7.0 +/- 3.3%; FM4C: 5.1 +/- 2.6 kg; and FFM4C: 68.3 +/- 7.3 kg) and before a competition (weight: 72.7 +/- 7.5 kg; %FM4C: 6.5 +/- 3.4%; FM4C: 4.8 +/- 2.6 kg; and FFM4C: 67.9 +/- 7.1 kg). Measures of body density assessed by air displacement plethysmography, bone mineral content by dual energy X-ray absorptiometry, and total-body water by bioelectrical impedance spectroscopy were used to estimate 4C model %FM, FM, and FFM. Seven SKF site models using both JP and Ev were used to estimate %FM, FM, and FFM along with the simplified Ev3SKF site. Changes in %FM, FM, and FFM were not significantly different from the 4C model. The regression model for the SKF in question and the reference method did not differ from the line of identity in estimating changes in %FM, FM, and FFM. The limits of agreement were similar, ranging from -3.4 to 3.6 for %FM, -2.7 to 2.5 kg for FM, and -2.5 to 2.7 kg for FFM. Considering the similar performance of both 7SKF- and 3SKF-based equations compared with the criterion method, these data indicate that either the 7- or 3-site SFK models are not valid to detect %FM, FM, and FFM changes of highly trained athletes. These results highlighted the inaccuracy of anthropometric models in tracking desired changes in body composition of elite male judo athletes before a competition.

The search for effective and long-term solutions to the problems caused by salmon lice Lepeophtheirus salmonis (Krøyer, 1837) has increasingly included biological/ecological mechanisms to combat infestation. One aspect of this work focuses on the host-associated stimuli that parasites use to locate and discriminate a compatible host. In this study we used electrophysiological recordings made directly from the antennule of adult lice to investigate the chemosensitivity of L. salmonis to putative chemical attractants from fish flesh, prepared by soaking whole fish tissue in seawater. There was a clear physiological response to whole fish extract (WFX) with threshold sensitivity at a dilution of 10 . When WFX was size fractionated, L. salmonis showed the greatest responses to the water-soluble fractions containing compounds between 1 and 10 kDa. The results suggest that the low molecular weight, water-soluble compounds found in salmon flesh may be important in salmon lice host choice.

Small detection distances coupled with rapid movements require copepods to respond to stimuli with behavioral latencies on the order of milliseconds. Receiving adequate sensory information in such a short time necessitates extremely rapid firing rates of the efferent receptors. Here we show that copepod mechanoreceptors can fire at frequencies up to 5 kHz in response to fluid mechanical stimuli. Neural activity at these frequencies enables these animals to code for a range of fluid velocities thus providing important information regarding the nature of different fluid disturbances.

Standardized methods for estimating the toxicity of anthropogenic compounds to aquatic organisms frequently fail to consider key elements of the test organisms' environment. Aquatic organisms exist in a fluid environment, and fluid dynamics may have an important influence on the response to toxicants. Rotifers are one of the three major groups of zooplankton and have been increasingly utilized in standardized toxicity testing. However, like other toxicity tests, assays with the species Brachionus calyciflorus are performed under static conditions in the absence of fluid motion. We investigated how fluid motion modifies pentachlorophenol (PCP) toxicity to B. calyciflorus using 24 h acute and 48 h reproductive toxicity tests. Estimates of PCP LC50s and reproduction EC50s in static conditions decreased from 738 and 1082 microg l(-1), respectively, to as low as 262 and 136 microg l(-1), respectively, in fluid motion. Flow analysis indicated that increased toxicant sensitivity can occur at ecologically relevant levels of fluid motion. Mechanistic studies indicated that fluid motion/toxicant interactions may result from the ability of fluid motion to cause shear stress, alter toxicant uptake, and/or alter the bioavailability of food. As fluid motion may have an important effect on the life histories of a wide variety of aquatic organisms, fluid motion/toxicant interactions may be an important consideration in other standard test organisms. These results raise questions about the accuracy of ecological risk assessments based on toxicity data from static conditions.