Major shift in the copepod functional community of the southern North Sea and potential environmental drivers

Abstract Copepods form the bulk of secondary production in marine ecosystems and are a major resource for higher trophic levels. Copepods are highly sensitive to environmental changes as they are ectotherms with a short life span whose metabolism and development depend on abiotic conditions. In turn, changes in their functional structure (i.e. functional trait composition) can have impacts on ecosystems. We examined changes in the copepod functional community in the North Sea over the past five decades, using a trait-based approach. We observed a shift around 1986–1988: the copepod community was initially dominated by larger herbivores, with a long development time, diapause ability, and highest abundances in summer. This community changed abruptly after 1986–1988, to a dominance of smaller carnivore taxa, with shorter development times, less ability to enter diapause, and that display higher abundances in autumn. This rapid reorganization could be driven by higher water temperatures, lower dinoflagellate abundances, and lower nutrient concentrations. These changes could impact adjacent trophic levels, such as phytoplankton on which several species graze or fish larvae, leading to a mismatch situation with consequences for fish recruitment. Our results emphasize the impact that global and regional changes could have on coastal ecosystems through the role played by copepods.</jats:p

Polyglutamine aggregate structure in vitro and in vivo; new avenues for coherent anti-Stokes Raman scattering microscopy

Coherent anti-Stokes Raman scattering (CARS) microscopy is applied for the first time for the evaluation of the protein secondary structure of polyglutamine (polyQ) aggregates in vivo. Our approach demonstrates the potential for translating information about protein structure that has been obtained in vitro by X-ray diffraction into a microscopy technique that allows the same protein structure to be detected in vivo. For these studies, fibres of polyQ containing peptides (D2Q15K2) were assembled in vitro and examined by electron microscopy and X-ray diffraction methods; the fibril structure was shown to be cross β-sheet. The same polyQ fibres were evaluated by Raman spectroscopy and this further confirmed the β-sheet structure, but indicated that the structure is highly rigid, as indicated by the strong Amide I signal at 1659 cm-1. CARS spectra were simulated using the Raman spectrum taking into account potential non-resonant contributions, providing evidence that the Amide I signal remains strong, but slightly shifted to lower wavenumbers. Combined CARS (1657 cm-1) and multi-photon fluorescence microscopy of chimeric fusions of yellow fluorescent protein (YFP) with polyQ (Q40) expressed in the body wall muscle cells of Caenorhabditis elegans nematodes (1 day old adult hermaphrodites) revealed diffuse and foci patterns of Q40-YFP that were both fluorescent and exhibited stronger CARS (1657 cm-1) signals than in surrounding tissues at the resonance for the cross β-sheet polyQ in vitro

Polyglutamine aggregate structure in vitro and in vivo; new avenues for coherent anti-Stokes Raman scattering microscopy

Coherent anti-Stokes Raman scattering (CARS) microscopy is applied for the first time for the evaluation of the protein secondary structure of polyglutamine (polyQ) aggregates in vivo. Our approach demonstrates the potential for translating information about protein structure that has been obtained in vitro by X-ray diffraction into a microscopy technique that allows the same protein structure to be detected in vivo. For these studies, fibres of polyQ containing peptides (D2Q15K2) were assembled in vitro and examined by electron microscopy and X-ray diffraction methods; the fibril structure was shown to be cross β-sheet. The same polyQ fibres were evaluated by Raman spectroscopy and this further confirmed the β-sheet structure, but indicated that the structure is highly rigid, as indicated by the strong Amide I signal at 1659 cm-1. CARS spectra were simulated using the Raman spectrum taking into account potential non-resonant contributions, providing evidence that the Amide I signal remains strong, but slightly shifted to lower wavenumbers. Combined CARS (1657 cm-1) and multi-photon fluorescence microscopy of chimeric fusions of yellow fluorescent protein (YFP) with polyQ (Q40) expressed in the body wall muscle cells of Caenorhabditis elegans nematodes (1 day old adult hermaphrodites) revealed diffuse and foci patterns of Q40-YFP that were both fluorescent and exhibited stronger CARS (1657 cm-1) signals than in surrounding tissues at the resonance for the cross β-sheet polyQ in vitro

ACTH Induced Behaviors and their Modulation by Serotonergic Agonists differ in Neonatal and Weanling Rat Pups

Four-day-old (P4) and 21–22-day-old (P21–22) rat pups received an intracisternal injection of either ACTH1-16NH2 or saline followed by a subcutaneous (SC) injection of saline, the serotonergic (5HT)1A agonists 8-OH-DPAT or ipsapirone, the 5HT1B agonist TFMPP or the 5HT2 agonist DOI. The ontogeny of ACTH-induced behaviors including grooming, yawn and stretch as well as various serotonin-related behaviors were recorded via time-sampling at 20 s intervals for a test duration of 50 min. ACTH induced slight but significant increases in grooming at P4, along with a significant increase in yawning. At this age the 5HT1B agonist TFMPP induced substantial increases in grooming, with no effect of the other agonists on this behavior. All of the serotonergic agonists, however, decreased ACTH-induced yawning at P4. At P21–22 ACTH induced more robust grooming than that observed at P4, although different in nature from adult-typical ACTH-induced grooming. This ACTH-induced grooming at P21–22 was attenuated by all of the serotonergic agonists. ACTH-induced yawning at P21–22 was not affected by the serotonergic agonists while ACTH-induced stretching was increased by the 5HT1B agonist TFMPP at this age. These data provide additional evidence of differential mediation of various ACTH-induced behaviors, and support other reports of ontogenetic alterations in the response to serotonergic manipulations during the neonatal to weanling age period

Fetal and Maternal Brain and Plasma Levels of Cocaine and Benzoylecgonine Following Chronic Subcutaneous Administration of Cocaine During Gestation in Rats

The distribution of cocaine and the cocaine metabolite benzoylecgonine (BE) in brain and plasma of Sprague-Dawley rat dams and their near-term fetuses was assessed 0.5 and 2 h post-injection on gestational day 20 following chronic daily subcutaneous injections of 10, 20, or 40 mg/kg/3 ml cocaine hydrochloride beginning on gestational day 8. Plasma concentrations of cocaine reached in the dams were found to be in the range of, or to exceed, those reported in human cocaine users. Dose-related increases in plasma and brain levels of cocaine in the dams and the fetuses were observed, particularly at 2 h post-injection. Fetal concentrations of cocaine in brain and plasma were approximately 2–3-fold less than those of the dams, suggesting that the placenta may somewhat restrict cocaine entry into fetal circulation. Brain/plasma cocaine ratios, however, were generally equivalent in the dams and fetuses, suggesting that once cocaine enters the circulation, its affinity for brain tissue is similar in the fetus and dam. Whereas plasma levels of BE, like cocaine levels per se, were greater in the dams than fetuses, BE concentrations in fetal brain were greater than those observed in maternal brain. These high levels of BE may contribute to the production of neurobehavioral alterations in cocaine-exposed offspring, given that this active cocaine metabolite has been shown to form molecular complexes with calcium ions (Misra and Mule 1975), thereby having the potential to influence a multiplicity of calcium-regulated developmental events. Taken together, the results of the present study suggest that the subcutaneous route may prove to be an appropriate means in rats for administering cocaine prenatally in investigations designed to assess potential neurobehavioral ramifications of gestational cocaine exposure