Ca2+-controlled competitive diacylglycerol binding of protein kinase C isoenzymes in living cells

The cellular decoding of receptor-induced signaling is based in part on the spatiotemporal activation pattern of PKC isoforms. Because classical and novel PKC isoforms contain diacylglycerol (DAG)-binding C1 domains, they may compete for DAG binding. We reasoned that a Ca2+-induced membrane association of classical PKCs may accelerate the DAG binding and thereby prevent translocation of novel PKCs. Simultaneous imaging of fluorescent PKC fusion proteins revealed that during receptor stimulation, PKCα accumulated in the plasma membrane with a diffusion-limited kinetic, whereas translocation of PKCɛ was delayed and attenuated. In BAPTA-loaded cells, however, a selective translocation of PKCɛ, but not of coexpressed PKCα, was evident. A membrane-permeable DAG analogue displayed a higher binding affinity for PKCɛ than for PKCα. Subsequent photolysis of caged Ca2+ immediately recruited PKCα to the membrane, and DAG-bound PKCɛ was displaced. At low expression levels of PKCɛ, PKCα concentration dependently prevented the PKCɛ translocation with half-maximal effects at equimolar coexpression. Furthermore, translocation of endogenous PKCs in vascular smooth muscle cells corroborated the model that a competition between PKC isoforms for DAG binding occurs at native expression levels. We conclude that Ca2+-controlled competitive DAG binding contributes to the selective recruitment of PKC isoforms after receptor activation

Single Transfer-Excitation Resonance Observed Via the Two-Photon Decay in He-like Ge³⁰⁺

We measured the 2E1 decay of the 1s2s 1S0 →1s2 1S0 transition in He-like germanium for 12- to 19-MeV/u Ge31+ +H2 collisions. The resonant population of the 2s2p 1P1 state by transfer excitation was isolated due to its cascading to the 1s2s 1S0 state. The experimental cross sections compare well with calculations using dielectronic recombination rates. The method gives the unique possibility to populate selectively the 1S0 state in heavy He-like ions

Roles of Gβγ in membrane recruitment and activation of p110γ/p101 phosphoinositide 3-kinase γ

Receptor-regulated class I phosphoinositide 3-kinases (PI3K) phosphorylate the membrane lipid phosphatidylinositol (PtdIns)-4,5-P2 to PtdIns-3,4,5-P3. This, in turn, recruits and activates cytosolic effectors with PtdIns-3,4,5-P3–binding pleckstrin homology (PH) domains, thereby controlling important cellular functions such as proliferation, survival, or chemotaxis. The class IB p110γ/p101 PI3Kγ is activated by Gβγ on stimulation of G protein–coupled receptors. It is currently unknown whether in living cells Gβγ acts as a membrane anchor or an allosteric activator of PI3Kγ, and which role its noncatalytic p101 subunit plays in its activation by Gβγ. Using GFP-tagged PI3Kγ subunits expressed in HEK cells, we show that Gβγ recruits the enzyme from the cytosol to the membrane by interaction with its p101 subunit. Accordingly, p101 was found to be required for G protein–mediated activation of PI3Kγ in living cells, as assessed by use of GFP-tagged PtdIns-3,4,5-P3–binding PH domains. Furthermore, membrane-targeted p110γ displayed basal enzymatic activity, but was further stimulated by Gβγ, even in the absence of p101. Therefore, we conclude that in vivo, Gβγ activates PI3Kγ by a mechanism assigning specific roles for both PI3Kγ subunits, i.e., membrane recruitment is mediated via the noncatalytic p101 subunit, and direct stimulation of Gβγ with p110γ contributes to activation of PI3Kγ

Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population

-How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae’s sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks

ROXADUSTAT FOR THE TREATMENT OF ANEMIA IN CHRONIC KIDNEY DISEASE PATIENTS NOT ON DIALYSIS: A PHASE 3 RANDOMIZED OPEN-LABEL ACTIVE-CONTROLLED STUDY (DOLOMITES)

Cilj rada: Ocjena oralnog inhibitora prolil-hidroksilaze hipoksijom induciranog faktora roksadustata za liječenje anemije povezane s kroničnom bubrežnom bolešću (KBB). Metode: U ovom su se randomiziranom, otvorenom, aktivnim lijekom kontroliranom ispitivanju faze 3 uspoređivali roksadustat i darbepoetin alfa (DA) u bolesnika s anemijom i KBB-om neovisnih o dijalizi tijekom razdoblja od ≤ 104 tjedna. Doze lijeka titrirale su se da bi se razina hemoglobina (Hb) korigirala i održala u rasponu od 10,0 do 12,0 g/dl. Primarna mjera ishoda bio je odgovor Hb-a u cjelovitom skupu podataka za analizu, koji se defi nirao kao Hb ≥ 11,0 g/dl i promjena početne vrijednosti Hb-a za ≥ 1,0 g/dl u bolesnika kojima je početni Hb iznosio > 8,0 g/dl odnosno promjena početne vrijednosti Hb-a za ≥ 2,0 g/dl u bolesnika kojima je početni Hb bio ≤ 8,0 g/dl tijekom prva 24 tjedna liječenja bez primjene dodatne terapije za postizanje zadovoljavajuće razine hemoglobina (rescue) (granica neinferiornosti: 15 %). Ključne sekundarne mjere ishoda uključivale su promjenu vrijednosti lipoproteina male gustoće (LDL), vrijeme do prve intravenske (i.v.) primjene željeza, promjenu srednjeg arterijskog tlaka i vrijeme do pojave hipertenzije. U ispitivanju su se ocjenjivale i nuspojave. Rezultati: Od 616 randomiziranih bolesnika (roksadustat: 323; DA: 293) 424 dovršilo je liječenje (roksadustat: 215; DA: 209). Odgovor Hb-a zabilježen uz roksadustat bio je neinferioran onome opaženome uz DA [roksadustat: 256/286 (89,5 %) u odnosu na DA: 213/273 (78,0 %); razlika: 11,51 %; interval pouzdanosti od 95 %: 5,66 - 17,36 %]. Roksadustat je održao vrijednosti Hb-a tijekom razdoblja do 2 godine. Roksadustat je bio neinferioran u odnosu na DA s obzirom na promjenu srednjeg arterijskog tlaka i vrijeme do nastupa hipertenzije, a superioran s obzirom na promjenu vrijednosti LDL-a i vrijeme do prve i.v. primjene željeza. Obje su skupine imale usporedive sigurnosne profi le. Rezultati pokazuju da nije bilo razlike između skupina s obzirom na kompozitne mjere ishoda, koje su uključivale velike kardiovaskularne štetne događaje (MACE) i MACE+ [MACE: 0,81 (0,52 - 1,25), P=0,339; MACE+: 0,90 (0,61 - 1,32), P=0,583]. Zaključak: Roksadustat je prihvatljiva opcija za liječenje anemije u bolesnika s KBB om neovisnih o dijalizi, koja omogućuje održane razine Hb-a tijekom razdoblja do 104 tjedna.Background: Roxadustat, an orally administered hypoxia-inducible factor prolyl hydroxylase inhibitor, is being evaluated for the treatment of anemia of chronic kidney disease (CKD). Methods: This randomized, open-label, active-controlled Phase 3 study compared roxadustat versus darbepoetin alfa (DA) in non-dialysis-dependent (NDD) CKD patients with anemia for ≤104 weeks. Doses were titrated to correct and maintain hemoglobin (Hb) within 10.0-12.0 g/dL. The primary endpoint was Hb response in the full analysis set, defi ned as Hb ≥11.0 g/dL and Hb change from baseline (BL; CFB) ≥1.0 g/dL in patients with BL Hb >8.0 g/dL or CFB ≥2.0 g/dL in patients with BL Hb ≤8.0 g/dL during the fi rst 24 weeks of treatment without rescue therapy (non-inferiority margin, -15%). The key secondary endpoints included change in low-density lipoprotein (LDL), time to fi rst intravenous (IV) iron use, change in mean arterial pressure (MAP), and time to hypertension occurrence. Adverse events were assessed. Results: Of 616 randomized patients (roxadustat, 323; DA, 293), 424 completed treatment (roxadustat, 215; DA, 209). Hb response with roxadustat was non-inferior to DA (roxadustat: 256/286, 89.5% versus DA: 213/273, 78.0%, difference 11.51%, 95% confi dence interval 5.66-17.36%). Roxadustat maintained Hb for up to 2 years. Roxadustat was non-inferior to DA for change in MAP and time to occurrence of hypertension, and superior for change in LDL and time to fi rst IV iron use. Safety profi les were comparable between the groups. Findings suggest that there was no difference between groups regarding the composite endpoints major adverse cardiovascular events (MACEs) and MACE+[MACE: 0.81 (0.52-1.25), p=0.339; MACE+: 0.90 (0.61-1.32), p=0.583]. Conclusions: Roxadustat is a viable option to treat anemia in NDD CKD patients maintaining Hb levels for up to 104 weeks

Evaluation of an electrolyte analyser for measurement of concentrations of ionized calcium and magnesium in cats

The goal of this study was to evaluate the Nova CRT 8 electrolyte analyser for determination of concentrations of ionized calcium (Cai) and magnesium (Mgi) in cats, todetermine the effects of sample handling and storage and to establish reference ranges. The precision and analytical accuracy of the Nova CRT 8 analyser were good. The concentrations of Cai and Mgi were significantly lower in aerobically handled serum samples than in those handled anaerobically. The concentrations of Cai and Mgi differed significantly among whole blood, plasma and serum. In anaerobically handled serum, the concentration of Cai was stable for 8 h at 22°C, for 5 days at 4°C and for 1 week at −20°C. The concentration of Mgi was stable for 4 h at 22°C but for less than 24 h at 4°C and for less than 1 week at −20°C. In serum from 36 cats, the reference ranges were 1.20-1.35 mmol/L for Cai and 0.47-0.59 mmol/L for Mgi. The Nova CRT 8 electrolyte analyser is suitable for determination of Cai and Mgi concentrations in cats. Anaerobically handled serum samples are recommended and, stored at room temperature, they yield accurate results when analysed within 4

Divergent responses of Atlantic cod to ocean acidification and food limitation

In order to understand the effect of global change on marine fishes, it is imperative to quantify the effects on fundamental parameters such as survival and growth. Larval survival and recruitment of the Atlantic cod (Gadus morhua) were found to be heavily impaired by end-of-century levels of ocean acidification. Here, we analysed larval growth among 35–36 days old surviving larvae, along with organ development and ossification of the skeleton. We combined CO2treatments (ambient: 503 µatm, elevated: 1,179 µatm) with food availability in order to evaluate the effect of energy limitation in addition to the ocean acidification stressor. As expected, larval size (as a proxy for growth) and skeletogenesis were positively affected by high food availability. We found significant interactions between acidification and food availability. Larvae fed ad libitum showed little difference in growth and skeletogenesis due to the CO2 treatment. Larvae under energy limitation were significantly larger and had further developed skeletal structures in the elevated CO2 treatment compared to the ambient CO2 treatment. However, the elevated CO2 group revealed impairments in critically important organs, such as the liver, and had comparatively smaller functional gills indicating a mismatch between size and function. It is therefore likely that individual larvae that had survived acidification treatments will suffer from impairments later during ontogeny. Our study highlights important allocation trade-off between growth and organ development, which is critically important to interpret acidification effects on early life stages of fish