Running a Marathon Induces Changes in Adipokine Levels and in Markers of Cartilage Degradation – Novel Role for Resistin

Running a marathon causes strenuous joint loading and increased energy expenditure. Adipokines regulate energy metabolism, but recent studies have indicated that they also exert a role in cartilage degradation in arthritis. Our aim was to investigate the effects of running a marathon on the levels of adipokines and indices of cartilage metabolism. Blood samples were obtained from 46 male marathoners before and after a marathon run. We measured levels of matrix metalloproteinase-3 (MMP-3), cartilage oligomeric protein (COMP) and chitinase 3-like protein 1 (YKL-40) as biomarkers of cartilage turnover and/or damage and plasma concentrations of adipokines adiponectin, leptin and resistin. Mean marathon time was 3∶30∶46±0∶02∶46 (h:min:sec). The exertion more than doubled MMP-3 levels and this change correlated negatively with the marathon time (r = –0.448, p = 0.002). YKL-40 levels increased by 56% and the effect on COMP release was variable. Running a marathon increased the levels of resistin and adiponectin, while leptin levels remained unchanged. The marathon-induced changes in resistin levels were positively associated with the changes in MMP-3 (r = 0.382, p = 0.009) and YKL-40 (r = 0.588, p<0.001) and the pre-marathon resistin levels correlated positively with the marathon induced change in YKL-40 (r = 0.386, p = 0.008). The present results show the impact of running a marathon, and possible load frequency, on cartilage metabolism: the faster the marathon was run, the greater was the increase in MMP-3 levels. Further, the results introduce pro-inflammatory adipocytokine resistin as a novel factor, which enhances during marathon race and associates with markers of cartilage degradation.     

Iodinated melatonin: preparation and characterization of the molecular structure by mass and 1H NMR spectroscopy

Synthetic melatonin was iodinated by treatment with potassium iodide in the presence of an oxidizing agent, Iodo-Gen. The iodination products of melatonin were extracted with chloroform and separated by HPLC. The fraction showing immunoreactivity with respect to melatonin antisera was characterized as iodomelatonin by mass spectrometry, so that the substitution of iodine had occurred at a ring carbon atom. 1H NMR spectra showed the iodine to be incorporated at the C-2 position of the indole moiety. The N-[2-(2-iodo-5-methoxy-1H-indol-3-yl)ethyl]acetamide (2-iodomelatonin) reported here is more useful than [3H]melatonin as a tracer in melatonin radioimmunoassay. This method offers also the possibility of preparing iodinated serotonin and other indoleamines for biological studies.     

Steady-State Phosphorylation of Light-Harvesting Complex II Proteins Preserves Photosystem I under Fluctuating White Light

According to the “state transitions” theory, the light-harvesting complex II (LHCII) phosphorylation in plant chloroplasts is essential to adjust the relative absorption cross section of photosystem II (PSII) and PSI upon changes in light quality. The role of LHCII phosphorylation upon changes in light intensity is less thoroughly investigated, particularly when changes in light intensity are too fast to allow the phosphorylation/dephosphorylation processes to occur. Here, we demonstrate that the Arabidopsis (Arabidopsis thaliana) stn7 (for state transition7) mutant, devoid of the STN7 kinase and LHCII phosphorylation, shows a growth penalty only under fluctuating white light due to a low amount of PSI. Under constant growth light conditions, stn7 acquires chloroplast redox homeostasis by increasing the relative amount of PSI centers. Thus, in plant chloroplasts, the steady-state LHCII phosphorylation plays a major role in preserving PSI upon rapid fluctuations in white light intensity. Such protection of PSI results from LHCII phosphorylation-dependent equal distribution of excitation energy to both PSII and PSI from the shared LHCII antenna and occurs in cooperation with nonphotochemical quenching and the proton gradient regulation5-dependent control of electron flow, which are likewise strictly regulated by white light intensity. LHCII phosphorylation is concluded to function both as a stabilizer (in time scales of seconds to minutes) and a dynamic regulator (in time scales from tens of minutes to hours and days) of redox homeostasis in chloroplasts, subject to modifications by both environmental and metabolic cues. Exceeding the capacity of LHCII phosphorylation/dephosphorylation to balance the distribution of excitation energy between PSII and PSI results in readjustment of photosystem stoichiometry.Plant acclimation to different quantities and qualities of light has been extensively investigated. The light quality experiments have usually concerned the red/blue and far-red light acclimation strategies, which have been closely related to the state transitions and the phosphorylation of the light-harvesting complex II (LHCII) proteins, Lhcb1 and Lhcb2, by the state transition7 (STN7) kinase (Allen, 2003; Bellafiore et al., 2005; Bonardi et al., 2005; Tikkanen et al., 2006; Rochaix, 2007). Such studies on acclimation to different qualities of light have uncovered key mechanisms required for the maintenance of photosynthetic efficiency in dense populations and canopies (Dietzel et al., 2008). However, the role of LHCII phosphorylation under fluctuations in the quantity of white light has been scarcely investigated. Light conditions in natural environments may be very complex with respect to the quantity of white light, which constantly fluctuates both in short- and long-term durations (Smith, 1982; Külheim et al., 2002). Thus, the acclimation strategies to natural environments must concomitantly meet the challenges of both high- and low-light acclimation. Changing cloudiness, for example, would initiate both the high-light and low-light acclimation signals in the time scale of minutes and hours, whereas the movements of leaves in the wind or the rapid movement of clouds would initiate even more frequent light acclimation signals. The kinetics of reversible LHCII phosphorylation is far too slow to cope with rapid environmental changes.The phosphorylation level of LHCII proteins in the thylakoid membrane is regulated by both the STN7 kinase and the counteracting PPH1/TAP38 phosphatase (Pribil et al., 2010; Shapiguzov et al., 2010). No definite results are available about regulation of the PPH1/TAP38 phosphatase, but the STN7 kinase is strongly under redox regulation (Lemeille et al., 2009) and controls the phosphorylation level of LHCII proteins under varying white light intensities as well as according to chloroplast metabolic cues, as described already decades ago (Fernyhough et al., 1983; Rintamäki et al., 2000; Hou et al., 2003). So far, research on the role of the STN7 kinase and LHCII phosphorylation in the light acclimation of higher plants has heavily focused on reversible LHCII phosphorylation and concomitant state transitions. The state 1-to-state 2 transition, by definition, means the phosphorylation of LHCII proteins, their detachment from PSII in grana membranes, and migration to the stroma membranes to serve in the collection of excitation energy to PSI (Fork and Satoh, 1986; Williams and Allen, 1987; Wollman, 2001; Rochaix, 2007; Kargul and Barber, 2008; Murata, 2009; Lemeille et al., 2010; Minagawa, 2011). Concomitantly, the absorption cross section of PSII decreases and that of PSI increases (Canaani and Malkin, 1984; Malkin et al., 1986; Ruban and Johnson, 2009). Indeed, state transitions have been well documented when different qualities (blue/red and far red) of light, preferentially exciting either PSII or PSI, have been applied.Different from state transitions, the white light intensity-dependent reversible LHCII phosphorylation does not result in differential excitation of the two photosystems (Tikkanen et al., 2010). Instead, both photosystems remain nearly equally excited independently whether the LHCII proteins are heavily phosphorylated or strongly dephosphorylated. Moreover, it is worth noting that the different qualities of light generally used to induce reversible LHCII phosphorylation and state transitions (blue/red and far-red lights) have usually been of very low intensity (for review, see Haldrup et al., 2001), and apparently, minimal protonation of the lumen takes place under such illumination conditions. Yet another difference between induction of LHCII protein phosphorylation by different qualities of light or different quantities of white light concerns the concomitant induction of PSII core protein phosphorylation. In the former case, the level of PSII core protein phosphorylation follows the phosphorylation pattern of LHCII proteins, whereas under different quantities of white light, the phosphorylation behavior of PSII core and LHCII proteins is the opposite (Tikkanen et al., 2008b).To gain a more comprehensive understanding of the physiological role of white light-induced changes in LHCII protein phosphorylation, we have integrated Arabidopsis (Arabidopsis thaliana) LHCII phosphorylation with other light-dependent regulatory modifications of light harvesting and electron transfer in the thylakoid membrane, which include the nonphotochemical quenching of excitation energy (for review, see Niyogi, 1999; Horton and Ruban, 2005; Barros and Kühlbrandt, 2009; de Bianchi et al., 2010; Jahns and Holzwarth, 2012; Ruban et al., 2012) and the photosynthetic control of electron transfer by the cytochrome b₆f (Cytb6f) complex (Rumberg and Siggel, 1969; Witt, 1979; Tikhonov et al., 1981; Bendall, 1982; Nishio and Whitmarsh, 1993; Joliot and Johnson, 2011; Suorsa et al., 2012; for review, see Foyer et al., 1990, 2012), both strongly dependent on lumenal protonation.It is demonstrated that the steady-state LHCII phosphorylation is particularly important under rapidly fluctuating light (FL) conditions. This ensures equal energy distribution to both photosystems, prevents the accumulation of electrons in the intersystem electron transfer chain (ETC), eliminates perturbations in chloroplast redox balance, and maintains PSI functionality upon rapid fluctuations in white light intensity.     

Middleborns Disadvantaged? Testing Birth-Order Effects on Fitness in Pre-Industrial Finns

Parental investment is a limited resource for which offspring compete in order to increase their own survival and reproductive success. However, parents might be selected to influence the outcome of sibling competition through differential investment. While evidence for this is widespread in egg-laying species, whether or not this may also be the case in viviparous species is more difficult to determine. We use pre-industrial Finns as our model system and an equal investment model as our null hypothesis, which predicts that (all else being equal) middleborns should be disadvantaged through competition. We found no overall evidence to suggest that middleborns in a family are disadvantaged in terms of their survival, age at first reproduction or lifetime reproductive success. However, when considering birth-order only among same-sexed siblings, first-, middle- and lastborn sons significantly differed in the number of offspring they were able to rear to adulthood, although there was no similar effect among females. Middleborn sons appeared to produce significantly less offspring than first- or lastborn sons, but they did not significantly differ from lastborn sons in the number of offspring reared to adulthood. Our results thus show that taking sex differences into account is important when modelling birth-order effects. We found clear evidence of firstborn sons being advantaged over other sons in the family, and over firstborn daughters. Therefore, our results suggest that parents invest differentially in their offspring in order to both preferentially favour particular offspring or reduce offspring inequalities arising from sibling competition.     

Design,synthesis and in vitro/in vivo evaluation of orally bioavailable prodrugs of a catechol-O-methyltransferase inhibitor

Compound 1 is an investigational, nanomolar inhibitor of catechol-O-methyltransferase (COMT) that suffers from poor oral bioavailability, most probably due to its low lipophilicity throughout most of the gastrointestinal tract and, to a lesser extent, its rapid systemic clearance. Several lipophilic esters were designed as prodrugs and synthesized in an attempt to optimize presystemic drug absorption. A modest twofold increase in 6-h exposure of 1 was observed with two prodrugs, compared to that of 1, after oral treatment in rats.     

Efficient estimation of emission probabilities in profile hidden Markov models

MOTIVATION: Profile hidden Markov models provide a sensitive method for performing sequence database search and aligning multiple sequences. One of the drawbacks of the hidden Markov model is that the conserved amino acids are not emphasized, but signal and noise are treated equally. For this reason, the number of estimated emission parameters is often enormous. Focusing the analysis on conserved residues only should increase the accuracy of sequence database search. RESULTS: We address this issue with a new method for efficient emission probability (EEP) estimation, in which amino acids are divided into effective and ineffective residues at each conserved alignment position. A practical study with 20 protein families demonstrated that the EEP method is capable of detecting family members from other proteins with sensitivity of 98% and specificity of 99% on the average, even if the number of free emission parameters was decreased to 15% of the original. In the database search for TIM barrel sequences, EEP recognizes the family members nearly as accurately as HMMER or Blast, but the number of false positive sequences was significantly less than that obtained with the other methods. AVAILABILITY: The algorithms written in C language are available on request from the authors.     

Pronatriuretic peptide is a sensitive marker of the endocrine function of teleost heart

We recently characterized a novel heart-specific hormone from salmon (salmon cardiac peptide, sCP). We have now prepared a recombinant plasmid expressing the NH(2)-terminal fragment of pro-sCP (NT-pro-sCP) and used it to set up a specific RIA for the peptide. Because of the sensitivity of the assay and the high circulating levels, NT-pro-sCP can be measured from as little as 2 microl of serum. This enables repeated sampling from the same animal in different experimental setups. Mechanical load increased the release of NT-pro-sCP from isolated perfused salmon ventricle, in parallel with sCP. Bolus injection of human endothelin-1 (ET-1; 1 microg) in the dorsal aorta of salmon resulted in an extensive increase of serum NT-pro-sCP (from 0.99 +/- 0.11 to 4.6 +/-1.5 nmol/l). The response was abolished by pretreatment with a specific type A ET (ET(A)) receptor antagonist (BQ-123) but not with a type B ET receptor antagonist (BQ-788). The NT-pro-sCP levels had a good correlation with those of sCP (r(2) = 0.75). Our results demonstrate the practical usefulness of circulating NT-pro-sCP as a marker of the endocrine function of salmon heart. They also suggest that ET-1 has an important role in regulating sCP release from teleost heart by an ET(A) receptor-mediated mechanism.