Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe

Recent studies from mountainous areas of small spatial extent (<2500 km²) suggest that fine‐grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate‐change impacts. Is this local spatial buffering restricted to topographically complex terrains? To answer this, we here study fine‐grained thermal variability across a 2500‐km wide latitudinal gradient in Northern Europe encompassing a large array of topographic complexities. We first combined plant community data, Ellenberg temperature indicator values, locally measured temperatures (LmT) and globally interpolated temperatures (GiT) in a modelling framework to infer biologically relevant temperature conditions from plant assemblages within <1000‐m² units (community‐inferred temperatures: CiT). We then assessed: (1) CiT range (thermal variability) within 1‐km² units; (2) the relationship between CiT range and topographically and geographically derived predictors at 1‐km resolution; and (3) whether spatial turnover in CiT is greater than spatial turnover in GiT within 100‐km² units. Ellenberg temperature indicator values in combination with plant assemblages explained 46–72% of variation in LmT and 92–96% of variation in GiT during the growing season (June, July, August). Growing‐season CiT range within 1‐km² units peaked at 60–65°N and increased with terrain roughness, averaging 1.97 °C (SD = 0.84 °C) and 2.68 °C (SD = 1.26 °C) within the flattest and roughest units respectively. Complex interactions between topography‐related variables and latitude explained 35% of variation in growing‐season CiT range when accounting for sampling effort and residual spatial autocorrelation. Spatial turnover in growing‐season CiT within 100‐km² units was, on average, 1.8 times greater (0.32 °C km^?1) than spatial turnover in growing‐season GiT (0.18 °C km^?1). We conclude that thermal variability within 1‐km² units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains.     

Preparation and characterisation of gelatine from the skin of harp seal (Phoca groendlandica)

This paper describes a method for extraction of gelatine from the skin of harp seal at mild acid conditions and gives a chemical and physical comparison of this gelatine with other mammalian and cod-skin gelatines. As compared to the wet weight of unhaired skin, a recovery of 11% dry gelatine was achieved after acid treatment and a two step water extraction at 60 and 75 degrees C. The chemical and physical properties of the gelatine were similar to the properties of commercial gelatines made from bovine and porcine skin, but significantly different from the properties of Atlantic cod-skin gelatine. The results indicated that seal skin gelatine can be used as a substitute for standard commercial gelatines for food technology applications.     

Physiology of diapause in the adult bark beetle, Ips acuminatus Gyll., studied in relation to cold hardiness

The ovarioles of the bark beetle, Ips acuminatus are telotrophic. Ovarian development is suppressed at an immature stage with primary germ cells present in the germaria. Lower oxygen consumption is found in beetles during autumn and early winter, and a substantial rise in mean respiration rates occurs in the beginning of January paralleled by a resumption of pre-vitellogenesis in all females maintained either at 3°C or out of doors after return to 21°C for 2 weeks. It is concluded that I. acuminatus enters faculative diapause soon after enclosure to the adult, and that diapause is terminated by mid-winter in beetles kept for 18 weeks at either 3°C or out of doors. The specimens remain thereafter in reproductive quiescence until ovarian development can proceed.Photic cues are neither involved in the elevation of mean respiration rates, nor needed to abolish the inhibition of ovarian maturation in beetles kept at 3°C or in those returned to 21°C. However, follicle formation in ovarioles is only seen in positive phototactic females reared during “long-day” conditions, suggesting a photoperiodic regulation of the later stages of vitellogenesis.Detectable amounts of ethylene glycol are found at the beginning of November in freezing-susceptible I. acuminatus hibernating in its galleries underneath bark of Scots pine (Pinus silvestris) at 3°C. The gradual catabolism of the cryoprotective solute at 3°C through December occurred at a time when individuals achieved the competence to resume ovarian maturation during 2 weeks at 21°C, but prior to the substantial rise in their mean respiration rates. However, resumption of ovarian development in spring had no effect on the capability of outdoor beetles to enhance their supercooling capacity when subjected to sub-zero temperatures. Since the ability to respond to temperature changes occurred in post-diapause I. acuminatus as well, the maintenance of prolonged cold hardiness in specimens could not be related to diapause itself. Apparently, the ability of beetles to resynthesize ethylene glycol when a detectable level is present in the organism remains unaltered during overwintering.     

The bat-eared fox: A dietary specialist?

We studied the degree of dietary specialisation of bat-eared foxes (Otocyon megalotis) by analysing 177 scats collected on a game ranch in central South Africa. Bat-eared foxes generally are considered to be insectivorous with a distinct specialisation on termites, however, our results indicated a much broader and opportunistic diet. Termites were detected in more than 90% of the scats throughout the year, but they only contributed 12–40% to the ingested biomass across seasons. Instead, fruits, primarily bluebush (Diospyros lycioides), were the most important food category in summer (63% biomass) as well as in autumn (74% biomass). Also, high niche breadth values (B = 5.7–6.9 for frequency of occurrence, B = 1.8–4.1 for biomass data) indicated a rather generalistic feeding behaviour. We also documented numerous cases of opportunistic scavenging on carcasses by bat-eared foxes. The difference with earlier dietary studies of bat-eared foxes might be attributable to geographical and ecological variations among sites and also partly to methodological differences. Concerning the latter, no previous studies considered biomass calculations but instead most assessed the frequency of occurrence of prey items, which likely overestimated the importance of small prey such as termites.     

Overexpression of DRG2 suppresses the growth of Jurkat T cells but does not induce apoptosis

Developmentally regulated GTP-binding protein (DRG) is a new subfamily within the superfamily of GTP-binding proteins. Its expression is regulated during embryonic development. To investigate the effect of the expression of DRG2 on cell growth, we constructed a human Jurkat-T-cell line that overexpresses DRG2. Overexpression of DRG2 suppressed the growth and the aggregation of Jurkat cells but did not induce apoptotic cell death. We used cDNA microarray analysis to examine the global changes in gene expression induced by an overexpression of DRG2. DNA array analyses identified genes that may suppress cell growth at a number of levels in multiple signaling cascades in Jurkat cells and also several prosurvival genes that may protect cells from apoptosis.     

Seasonal Changes in Osmotic and Ionic Regulation in Arctic Charr, Salvelinus Alpinus, From a High- and a Sub-arctic Anadromous Population

Seasonal changes in hypoosmoregulatory capacity were studied in hatchery-reared offspring of a high-Arctic strain of anadromous Arctic charr, Salvelinus alpinus, from Svalbard (79°N) and a sub-Arctic strain from Hammerfest, north Norway (70°N). The fish were held in freshwater under simulated, natural light conditions (Tromsø, 69°N) and natural water temperatures, and hypoosmoregulatory capacity was determined by seawater challenge tests between February and November. An improved hypoosmoregulatory capacity was seen in both strains at the time when their wild conspecifics migrate to the sea. The time when maximum hypoosmoregulatory capacity was achieved differed significantly between the two strains, suggesting that there may be genetic differences between the two populations in how environmental cues (e.g. temperature, photoperiod) entrain the development of seawater tolerance. The development and loss of hypoosmoregulatory capacity seemed to be more rapid and abrupt in the Svalbard charr than in the Hammerfest charr. This is hypothesised to be an adaptation to the stochastic and unpredictable variations in the time when the fish are allowed to migrate in the high-Arctic, and the need to prevent migration in years when the ice break occurs very late.     

A Genome-wide Association Study of Lung Cancer Identifies a Region of Chromosome 5p15 Associated with Risk for Adenocarcinoma

Three genetic loci for lung cancer risk have been identified by genome-wide association studies (GWAS), but inherited susceptibility to specific histologic types of lung cancer is not well established. We conducted a GWAS of lung cancer and its major histologic types, genotyping 515,922 single-nucleotide polymorphisms (SNPs) in 5739 lung cancer cases and 5848 controls from one population-based case-control study and three cohort studies. Results were combined with summary data from ten additional studies, for a total of 13,300 cases and 19,666 controls of European descent. Four studies also provided histology data for replication, resulting in 3333 adenocarcinomas (AD), 2589 squamous cell carcinomas (SQ), and 1418 small cell carcinomas (SC). In analyses by histology, rs2736100 (TERT), on chromosome 5p15.33, was associated with risk of adenocarcinoma (odds ratio [OR] = 1.23, 95% confidence interval [CI] = 1.13–1.33, p = 3.02 × 10⁻⁷), but not with other histologic types (OR = 1.01, p = 0.84 and OR = 1.00, p = 0.93 for SQ and SC, respectively). This finding was confirmed in each replication study and overall meta-analysis (OR = 1.24, 95% CI = 1.17–1.31, p = 3.74 × 10⁻¹⁴ for AD; OR = 0.99, p = 0.69 and OR = 0.97, p = 0.48 for SQ and SC, respectively). Other previously reported association signals on 15q25 and 6p21 were also refined, but no additional loci reached genome-wide significance. In conclusion, a lung cancer GWAS identified a distinct hereditary contribution to adenocarcinoma.     

Structure of a ternary Naa50p (NAT5/SAN) N-terminal acetyltransferase complex reveals the molecular basis for substrate-specific acetylation

The co-translational modification of N-terminal acetylation is ubiquitous among eukaryotes and has been reported to have a wide range of biological effects. The human N-terminal acetyltransferase (NAT) Naa50p (NAT5/SAN) acetylates the α-amino group of proteins containing an N-terminal methionine residue and is essential for proper sister chromatid cohesion and chromosome condensation. The elevated activity of NATs has also been correlated with cancer, making these enzymes attractive therapeutic targets. We report the x-ray crystal structure of Naa50p bound to a native substrate peptide fragment and CoA. We found that the peptide backbone of the substrate is anchored to the protein through a series of backbone hydrogen bonds with the first methionine residue specified through multiple van der Waals contacts, together creating an α-amino methionine-specific pocket. We also employed structure-based mutagenesis; the results support the importance of the α-amino methionine-specific pocket of Naa50p and are consistent with the proposal that conserved histidine and tyrosine residues play important catalytic roles. Superposition of the ternary Naa50p complex with the peptide-bound Gcn5 histone acetyltransferase revealed that the two enzymes share a Gcn5-related N-acetyltransferase fold but differ in their respective substrate-binding grooves such that Naa50p can accommodate only an α-amino substrate and not a side chain lysine substrate that is acetylated by lysine acetyltransferase enzymes such as Gcn5. The structure of the ternary Naa50p complex also provides the first molecular scaffold for the design of NAT-specific small molecule inhibitors with possible therapeutic applications.