Idle slow as you grow old: longitudinal age-related metabolic decline in a wild passerine

Physiological changes due to aging are intensively studied as they have far-reaching implications for the mechanistic and evolutionary theories of senescence. In this respect, metabolic rate has been suggested to play a role for the deterioration and damage of cells and tissues with age, partly due to the generation of reactive oxygen species. To mitigate such damage, individuals can be predicted to reduce basal metabolic rate (BMR) with age. This prediction has been verified in humans and some laboratory animals but never in wild animal populations. We analyzed the change in BMR within individuals across years in two wild populations of great tit (Parus major) differing in BMR. Great tits, living under stressful conditions towards the northern limit of their distribution, decreased their BMR as they aged whereas no such decrease was found in a southern population. Thus, we found a clear decline only in the population with the highest BMR levels. This study provides the first evidence of an age-related decline in BMR for a wild homeotherm.     

The nature of M-O bond in MOX4 compounds (M = Os, Ru; X = F, Cl, Br, I)

The nature of M-O bond in MOX₄ compounds (where M = Ru or Os and X = F, Cl, Br or I) was analyzed by density functional theory methods at the BP86/LANL2DZ level of theory. The obtained charge density was analyzed by Fermi hole analysis, natural bond order (NBO) analysis and atoms-in-molecules (AIM)-based methods. The M-O bond is essentially a triple bond, although strongly polarized. The clearest differences in bonding between the Ru and Os compounds can be found in the M-O σ bonds, where in the Os compounds we find more charge density resting close to O.     

Time and concentration dependence of the action of cortisol on fibroblasts in vitro

The effect of cortisol on cultured fibroblasts from human skin were studied. After 0–84-h preincubations in the presence of cortisol the cells were labeled for 12 h with [³H]thymidine, [³H]proline or [³H]glucosamine and the radioactivity incorporated into DNA, collagen, total proteins, hyaluronic acid and sulphated glycosaminoglycans was determined.Cortisol (1 · 10^?5 M) caused a rapid, progressive decrease in the synthesis of hyaluronic acid when compared to the controls. Similarly, it decreased the synthesis of sulphated glycosaminoglycans and DNA, but this was seen first after 12- and 24-h preincubations, respectively. The synthesis of collagen and other proteins was significantly increased when the preincubation time was 0–24 h. This stimulation, however, turned to inhibition when an 84-h preincubation was used. It was found that 1 · 10^?7 M cortisol was the lowest concentration which caused the early inhibition in hyaluronate synthesis, while even 1 · 10^?8 M was sufficient after an 84-h preincubation. The syntheses of sulphated glucosaminoglycans and DNA were significantly inhibited by 1 · 10^?8 and 1 · 10^?7 M cortisol, after an 54-h preincubation, respectively. Thus, the studies of cortisol effects on fibroblast functions may result in quite variable conclusions unless the time sequence and the steroid concentration effects are taken into account.     

Musa puspanjaliae sp. nov. (Musaceae) from Arunachal Pradesh,India

Musa puspanjaliae R. Gogoi & Häkkinen, a new species of Musa sect. Musa, is described and illustrated from west Kameng, Arunachal Pradesh, India based on morphological characteristics observed in the field. The new species is common in Sessa, Zero Point to Ramda on Sepa road of west Kameng and Hazi Basti, Ziro of lower Subansiri district in Arunachal Pradesh. A key to M. puspanjaliae and related taxa is provided.     

Arctic moistening provides negative feedbacks to riparian plants

Arctic moistening will affect the circumpolar forested riparian ecosystems. Upward trends observed for precipitation in high latitudes illustrate that the moistening may be underway to influence the woody biomass production near the inland waters, lakes and streams with effects on carbon pools and fluxes. Although the flooding and waterlogging tolerance of seedlings has been investigated, our understanding of responses in mature trees is still limited. Here we employ tree‐ring δ¹³C and width data from a subarctic riparian setting in Lapland, where artificially high lake level (HLL) has already altered the ecophysiological and growth responses of riparian Pinus sylvestris trees to external drivers under conditions simulating moister environment. Prior to the HLL event, the carbon assimilation rate was primarily limited by irradiance as reflected in the δ¹³C data and the radial growth of south‐facing riparian trees remained increased in comparison to shaded upland trees. By contrast, the riparian trees were not similarly benefited during the HLL period when reduced assimilation depleted the riparian in comparison to upland δ¹³C despite of increased irradiance. As a result, the radial growth of riparian trees was markedly reduced over the HLL event while the upland trees benefited from increased irradiance and summer time warming. Although the production of biomass at high latitudes is commonly considered temperature‐limited, our results highlight the increasing role of Arctic moistening to limit the growth when increased precipitation (cloudiness) reduces the incoming solar radiation in general and when the riparian habitat becomes increasingly waterlogged in particular. The effects of high‐latitude warming to induce higher biomass productivity may be restricted by negative feedbacks.     

Improved application of the diphenylamine reaction for the determination of DNA

An improved procedure is described for the separation and quantitation of DNA from biological samples. Following papain digestion, DNA was separated from other cell material with CdCl₂ precipitation onto a glass-fiber filter and quantitated easily by the modified diphenylamine reaction.     

Cross sectional properties of the human radial tuberosity

This study examines the cross sectional shape and biomechanical properties of the radial bone shaft at mid-radial tuberosity (RT) musculoskeletal marker (MSM). This information will provide insight into factors affecting bone modelling at muscle insertions. Radial shaft cross-sectional properties at radial tuberosity area (RTA) have not been previously studied. The material consists of 54 male skeletons derived from autopsies performed during the 1920s and 1930s and housed at the Central Natural History Museum, University of Helsinki. The age, sex and occupation of these individuals are known. We applied a pQCT (peripheral quantitative computed tomography) scan on the mid-site of the radial tuberosity to investigate the cross-sectional shape, the bone mineral density (BMD) and biomechanical properties. Our results indicate that bone modelling does not produce increased wall thickness or BMD at the RT site. Additionally we noticed that aging and physical activity affect the biomechanics of the RT and that the bone distribution at mid-RT is adapted to accommodate the biceps brachii muscle pull. We also found a clear association between RTA and biomechanical properties of mid-RT cross section.