Evolutionary adaptation to environmental stressors: a common response at the proteomic level

Mechanistic trade‐offs between traits under selection can shape and constrain evolutionary adaptation to environmental stressors. However, our knowledge of the quantitative and qualitative overlap in the molecular machinery among stress tolerance traits is highly restricted by the challenges of comparing and interpreting data between separate studies and laboratories, as well as to extrapolating between different levels of biological organization. We investigated the expression of the constitutive proteome (833 proteins) of 35 Drosophila melanogaster replicate populations artificially selected for increased resistance to six different environmental stressors. The evolved proteomes were significantly differentiated from replicated control lines. A targeted analysis of the constitutive proteomes revealed a regime‐specific selection response among heat‐shock proteins, which provides evidence that selection also adjusts the constitutive expression of these molecular chaperones. Although the selection response in some proteins was regime specific, the results were dominated by evidence for a “common stress response.” With the exception of high temperature survival, we found no evidence for negative correlations between environmental stress resistance traits, meaning that evolutionary adaptation is not constrained by mechanistic trade‐offs in regulation of functional important proteins. Instead, standing genetic variation and genetic trade‐offs outside regulatory domains likely constrain the evolutionary responses in natural populations.     

Long‐term tag retention on two species of small cetaceans

The effects of tagging on small cetaceans are difficult to assess due to logistical difficulties in recapturing the whales. In this study two narwhals, Monodon monoceros, and five harbor porpoises, Phocoena phocoena, were recaptured between 297 and 767 days after instrumentation with satellite transmitters. The transmitters were mounted by pins that were pushed through the fins of the porpoises or the backs of the narwhals. Overall body condition seemed unaffected by the instrumentations. Macroscopical examination revealed that umbilicalization of the tissue surrounding the pins was almost complete. On one of the narwhals the reepithelialization created a closed tunnel where the pins were isolated from the subdermal tissue, however the reepithelialization was incomplete around the middle of the pin and a low‐grade inflammation increased with decreasing thickness of epidermis. The inflammation consisted of mononuclear cells, mainly lymphocytes. With increasing inflammation the number of neutrophils and macrophages increased. In the lymphoid follicular hyperplasia macrophages and a few neutrophils were found, in one case accompanied by Splendore‐Hoeppli material with radiating eosinophilic clubs and Gram‐positive cocci. Immunohistochemical staining of the cocci for Staphylococcus aureus was positive. The observations from the recaptured cetaceans suggest that the instrumentations caused only temporary and low‐grade inflammatory responses.     

Active bacteria (CTC+) in temperate lakes: temporal and cross-system variations

The temporal variation in the abundance and proportion of highlyrespiration-active bacteria in the eutrophic lakes Esrum andFrederiksborg Slotssø was determined with the redox dye5-cyano-2,3-ditolyl tetrazolium chloride (CTC). In addition,a comparative late summer study was undertaken across a gradientof nutrient enrichment in Danish lakes. The purpose was to investigatethe importance of substrate (chlorophyll) and temperature forthe control of CTC-active cells (CTC+). The abundance of CTC+cells was much lower and more variable than the total numberof cells counted after 4',6-diamidino-2-phenylindole (DAPI)staining. The proportion of CTC+ cells in Lake Esrum and FrederiksborgSlotssø was normally <5%, and between 2.5 and 20%in 14 other lakes. The abundance as well as the proportion ofCTC+ cells increased with chlorophyll in Lake Esrum and FrederiksborgSlotssø, and chlorophyll explained 43% of the variabilityin CTC+ abundance. In the comparative study, the abundance ofCTC+ cells increased along the chlorophyll gradient, which explained49% of the variability. The results showed that the abundanceand, to a lesser degree, the proportion of CTC+ bacteria werecontrolled by substrate supply. One consequence of the low abundanceof active bacteria is that in situ growth rates scaled to CTC+cells are 3- to 7-fold higher than those scaled to DAPI counts.It is suggested that studies on factors controlling bacterioplanktonactivity at the single-cell level should be investigated scaledto active cells.     

Characterization of two novel nuclear BTB/POZ domain zinc finger isoforms. Association with differentiation of hippocampal neurons, cerebellar granule cells, and macroglia.

BTB/POZ (broad complex tramtrack bric-a-brac/poxvirus and zinc finger) zinc finger factors are a class of nuclear DNA-binding proteins involved in development, chromatin remodeling, and cancer. However, BTB/POZ domain zinc finger factors linked to development of the mammalian cerebral cortex, cerebellum, and macroglia have not been described previously. We report here the isolation and characterization of two novel nuclear BTB/POZ domain zinc finger isoforms, designated HOF(L) and HOF(S), that are specifically expressed in early hippocampal neurons, cerebellar granule cells, and gliogenic progenitors as well as in differentiated glia. During embryonic development of the murine cerebral cortex, HOF expression is restricted to the hippocampal subdivision. Expression coincides with early differentiation of presumptive CA1 and CA3 pyramidal neurons and dentate gyrus granule cells, with a sharp decline in expression at the CA1/subicular border. By using bromodeoxyuridine labeling and immunohistochemistry, we show that HOF expression coincides with immature non-dividing cells and is down-regulated in differentiated cells, suggesting a role for HOF in hippocampal neurogenesis. Consistent with the postulated role of the POZ domain as a site for protein-protein interactions, both HOF isoforms are able to dimerize. The HOF zinc fingers bind specifically to the binding site for the related promyelocytic leukemia zinc finger protein as well as to a newly identified DNA sequence.     

Locked nucleic acid: a potent nucleic acid analog in therapeutics and biotechnology

Locked nucleic acid (LNA) is a class of nucleic acid analogs possessing very high affinity and excellent specificity toward complementary DNA and RNA, and LNA oligonucleotides have been applied as antisense molecules both in vitro and in vivo. In this review, we briefly describe the basic physiochemical properties of LNA and some of the difficulties that may be encountered when applying LNA technology. The central part of the review focuses on the use of LNA molecules in regulation of gene expression, including delivery to cells, stability, unspecific effects, toxicity, pharmacokinetics, and design of LNA oligonucleotides. The last part evaluates LNA as a diagnostic tool in genotyping.     

Eicosapentaenoic Acid and Docosahexaenoic Acid in Whole Blood Are Differentially and Sex-Specifically Associated with Cardiometabolic Risk Markers in 8–11-Year-Old Danish Children

n-3 long-chain polyunsaturated fatty acids improve cardiovascular risk markers in adults. These effects may differ between eicosapentaenoic acid (EPA, 20∶5n-3) and docosahexaenoic acid (DHA, 22∶6n-3), but we lack evidence in children. Using baseline data from the OPUS School Meal Study we 1) investigated associations between EPA and DHA in whole blood and early cardiometabolic risk markers in 713 children aged 8–11 years and 2) explored potential mediation through waist circumference and physical activity and potential dietary confounding. We collected data on parental education, pubertal stage, 7-day dietary records, physical activity by accelerometry and measured anthropometry, blood pressure, and heart rate. Blood samples were analyzed for whole blood fatty acid composition, cholesterols, triacylglycerol, insulin resistance by the homeostatic model of assessment (HOMA-IR), and inflammatory markers. Whole blood EPA was associated with a 2.7 mmHg (95% CI 0.4; 5.1) higher diastolic blood pressure per weight% EPA, but only in boys. Heart rate was negatively associated with both EPA and DHA status (P = 0.02 and P = 0.002, respectively). Whole blood EPA was negatively associated with triacylglycerol (P = 0.003) and positively with total cholesterol, low density and high density lipoprotein (HDL) cholesterol and HDL:triacylglycerol (all P<0.01) whereas DHA was negatively associated with insulin and HOMA-IR (P = 0.003) and tended to be negatively associated with a metabolic syndrome-score (P = 0.05). Adjustment for waist circumference and physical activity did not change the associations. The association between DHA and HOMA-IR was attenuated but remained after adjustment for fiber intake and none of the other associations were confounded by dietary fat, protein, fiber or energy intake. This study showed that EPA status was negatively associated with triacylglycerol and positively with cholesterols whereas DHA was negatively associated with insulin resistance, and both were inversely associated with heart rate in children. The sex-specific associations with blood pressure confirm our previous findings and warrant further investigation.     

The muskoxen Ovibos moschatus in north and northeast Greenland: population trends and the influence of abiotic parameters on population dynamics

This paper presents the first long term (1960–89) data set on both muskox Ovibos moschatus density and weather parameters in north and northeast Greenland The muskoxen appear to have expenenced a 25 yr favourable period from the early 1960 'ies to the mid 1980' ies, in which density increased and reached a maximum level The population minimum around 1960 probably represents a long term minimum, following a long, generally unfavourable period between 1940–60 Variation in the local population trends from the southern parts of the muskox distribution m northeast Greenland to the northeast parts, can be divided into three geographical areas (72°–75°N, 75°–77°30 'N, and north of 79°30' N), where density dependent and density independent factors affecting muskox populations are apparently different Regional population stability does not increase towards the north Two density independent (abiotic) factors seem to be of prime importance in determining the muskox population density and distribution in northeast Greenland 1) the amount of winter precipitation affects the distribution of muskoxen negatively, inducing local migrations, but does not have a direct negative effect on large scale variation in density,11) ablation (i.e melting of the upper snow layer) and concomitant ice crust formation in winter have a highly negative effect on muskox density in the southern range, but not in the northern range The two abiotic factors, which show a considerable variation from north to south, are statistically independent and seem to be triggered by different weather conditions The predictions that follow from a climatic model both with respect to the direct influence of abiotic factors on muskox density and the indirect influence of climatic fluctuation, are not fully supported by the data presented here     

Adenosine stimulated postimplantational regeneration of 5-adenine nucleotides in rabbit kidney grafts

The ability to regenerate the adenylate content in renal tissue appears to fail in rabbit kidney grafts, cold stored for 24 hours. The post implantational adenylate regeneration which did not occur, took place within the first lo minutes of re-established circulation. Thirty and sixty minutes of re-vascularization did not give any additional adenylate synthesis. The presence of adenosine (2.5 mM) in the preservation fluid, and that taken up by the kidney tissue during in vitro storage, brought about a significant increase in adenylate regeneration during the postimplantational period, independennt of a parallel increase in renal blood flow, and irrespective of the fact that adenosine did not show any adenylate preserving effect in vitro. The present results suggest that in long-term stored rabbit kidney grafts there occurs a relative postischaemic lack of intracellular available purine precursors. Owing to the filtration inhibiting effect of adenosine a study of the correlation between kidney function and adenylate regeneration was not possible.     

Gastric inflammatory markers and interleukins in patients with functional dyspepsia, with and without Helicobacter pylori infection

Helicobacter pylori is the most important cause of gastritis, peptic ulcers and the development of gastric cancer. The chronic active inflammation is dominated by neutrophils, macrophages, lymphocytes and plasma cells. Several interleukins (IL-8, IL-10 and IFN-gamma) are involved in the inflammatory process in the gastric mucosa. The aim of this study was to investigate the gastric inflammation in patients with functional dyspepsia. Fifty-three consecutive patients were included and antral biopsies were obtained for histology, culture and immunohistochemistry. The sections were examined for the interleukins IL-4, IL-6, IL-8, IL-10 and IFN-gamma as well as for the cell markers CD4, CD8, CD14, Cd19, CD25 and CD30. Only CD4 and CD19 were significantly increased in patients with increased gastric inflammation and increased density of H. pylori. However, several of the examined markers (IFN-gamma, IL-8, IL-10 and CD14) showed a non-significant trend to be increased in patients with extensive gastric inflammation and high density of H. pylori. Therefore, an arbitrary index (IM11) for all the 11 immunological markers was made as an average value for each of the four morphological groups. For the four morphologically different groups of patients the values were 0.49, 0.77, 0.86 and 1.25, respectively. Significant increases in the index from none to moderate antral inflammation as well as the density of H. pylori were found (p<0.001). By using an index of inflammatory markers trends can be summarized and thereby significant which may be of importance when gastric inflammation is investigated in children and patients with functional dyspepsia.