Covariance modulates the effect of joint temperature and food variance on ectotherm life‐history traits

Understanding animal performance in heterogeneous or variable environments is a central question in ecology. We combine modelling and experiments to test how temperature and food availability variance jointly affect life‐history traits of ectotherms. The model predicts that as mean temperatures move away from the ectotherm's thermal optimum, the effect size of joint thermal and food variance should become increasingly sensitive to their covariance. Below the thermal optimum, performance should be positively correlated with food–temperature covariance and the opposite is predicted above it. At lower temperatures, covariance should determine whether food and temperature variance increases or decreases performance compared to constant conditions. Somewhat stronger than predicted, the covariance effect below the thermal optimum was confirmed experimentally on an aquatic ectotherm (Daphnia magna) exposed to diurnal food and temperature variance with different amounts of covariance. Our findings have important implications for understanding ectotherm responses to climate‐driven alterations of thermal mean and variance.     

Reliable and rapid discrimination of congeneric species by mtDNA SNP analysis by multiplex PCR: application on three Trachurus and two Mullus fish species as model cases

We present a reliable, time-saving, and cost-effective multiplex PCR assay for discriminating congeneric species. Three fish species of the genus Trachurus and two of the genus Mullus served as model cases. Our multiplex PCR method interrogates species-specific diagnostic mitochondrial single nucleotide polymorphisms (mtSNPs). We selected two sets of mtSNPs that are organized in two multiplex systems for the Trachurus and the Mullus species, respectively. In both systems, all individuals tested could be safely assigned to one of the three Trachurus or two Mullus species. This novel SNP typing system offers a convenient and robust DNA profiling system suitable for large-scale identification of commercial fish species, for species with cryptic larvae or during juvenile stages, as well as for wildlife forensics. Handling editor: Christian Sturmbauer     

DNA barcode ITS2 coupled with high resolution melting (HRM) analysis for taxonomic identification of Sideritis species growing in Greece

Identification of genotypes in Sideritis is complicated owing to the morphological similarity and common occurrence of natural hybridisation within Sideritis species. Species- and genotype-specific DNA markers are very useful for plant identification, breeding and preservation programs. Herein, a real-time polymerase chain reaction (PCR) of ITS2 barcode region coupled with high resolution melting-curve (HRM) analysis was evaluated for an accurate, rapid and sensitive tool for species identification focusing on seven Sideritis species growing in Greece. The HRM assay developed in this study is a rapid and straightforward method for the identification and discrimination of the investigated Sideritis species. This assay is simple compared to other genotyping methods as it does not require DNA sequencing or post-PCR processing. Therefore, this method offers a new alternative for rapid detection of Sideritis species.     

Summer Squash Identification by High-Resolution-Melting (HRM) Analysis Using Gene-Based EST–SSR Molecular Markers

Cucurbita pepo (squash, pumpkin, gourd), a worldwide cultivated vegetable of American origin, is extremely variable in fruit characteristics. Most of its widely grown commercial types are known as summer squashes and belong to the elongated forms of C. pepo ssp. pepo (Cocozelle, Vegetable marrow and Zucchini groups). Here, we have integrated the high-resolution-melting (HRM) analysis method with expressed sequence tags–simple sequence repeat (EST–SSR) marker genotyping, in order to facilitate the identification of 36 summer squash landraces originated from Greece. The six EST–SSR loci used were informative and generated a unique melting curve profile of EST-derived microsatellites for each accession allowing their comparison and classification. Moreover, HRM was highly informative, as by using only four microsatellite markers we were able to discriminate 36 summer squash landraces and by using six EST–SSRs. We were able to construct a highly informative and discriminative dendrogram where the 36 genotypes were classified in six distinct clusters. Furthermore, we acquired information about the genes containing the EST–SSRs using bioinformatics tools. We found that the EST–SSRs used in this study were hybridizing to genes involved in stress response to heavy metals and biotic stresses or the production of flavonoids or symporters of important nitrogen sources, like xanthine and uric acid amongst others. The results presented here suggest that the panel of EST–SSR markers used in combination with HRM analysis could be useful in a variety of applications, like squash biodiversity assessment but most importantly in managing squash germplasm to improve breeding programs.     

Εx-vivo effect of dexamethasone on cytokine production from whole blood of septic patients: Correlation with disease severity

Background: Controversial findings of former clinical trials on the effect of low dose hydrocortisone in patients with septic shock led to investigate the effect of corticosteroids on the production of cytokines from endotoxin (LPS)-stimulated whole blood. Methods: Whole blood from 33 septic patients was sampled within 24 h alter diagnosis. Hydrocortisone was not administered during follow-up. Whole blood was stimulated with 30 ng/ml of LPS in the presence of 0.01, 0.1, 1 and 10 μM of dexamethasone. Concentrations of cytokines and of sTREM-1 were estimated in supernatants after six hours of incubation. Results: Dexamethasone inhibited LPS-stimulated release of ΤΝFα, of IL-6, of IL-8 and of IL-10 in dose-dependent manner. A dual effect on the kinetics of release of IL-1β and of sTREM-1 was shown. Release of IL-1β was either decreased, what was connected with unfavorable outcome, or it was unaffected what was connected with a favorable outcome. Release of sTREM-1 was either increased, what was connected with unfavorable outcome, or it was decreased what was connected with a favorable outcome. Conclusions: Part of the beneficiary effect of corticosteroids in sepsis may be due to an effect on the release of IL-1β and of sTREM-1. This effect does not seem to be homogeneous for all septic patients.     

Parathyroid hormone-related protein is reduced in severe chronic heart failure

In the cardiovascular system, parathyroid hormone-related peptide (PTHrP) is expressed in various cells such as cardiac vascular smooth muscle cells, coronary endothelial cells and cardiomyocytes and acts as an autocrine/paracrine substance. We compared PTHrP levels in 35 consecutive patients with severe CHF (33 male, mean age 66.2 +/- 8.9 years) with 26 normal controls (24 male, mean age 63.1 +/- 8.6 years). PTHrP levels were reduced in severe CHF patients (11.10 +/- 1.37 fmol/ml) compared with the controls (20.62 +/- 3.30 fmol/ml, p = 0.005). PTHrP values decreased as a function of New York Heart Association classification. These results suggest that PTHrP levels decrease in proportion to the severity of heart failure and could potentially be used to monitor progression of disease non-invasively.     

Adequacy of saliva 17-hydroxyprogesterone determination using various collection methods

Steroids determination in saliva offers several advantages. The collection of saliva is a noninvasive, less stressful technique than blood withdrawal and reflects the circulating unbound fractions. The suitability of saliva for 17-hydroxyprogesterone and cortisol determinations has been documented in healthy subjects as well as in diseases like Congenital Adrenal Hyperplasia and Cushing syndrome. The aim of the study was to compare the influence of different collection methods on the results of 17-hydroxyprogesterone measurement in saliva collected by different ways, using commercially available RIAs developed for plasma. 17-hydroxyprogesterone was determined in 64 healthy adult volunteers (30 males, 34 females) in serum (Group SE) and in saliva collected before meals at 8-10 p.m. by directly spitting into a plastic tube (Group SP), using a cotton swab (Group SA) and using a polyester swab Salivette (Group SB). We used a commercially available direct radioimmunoassay without separation technique. The 17-hydroxyprogesterone mean values (ng/ml) were 1.16+/-1.3 (Group SE), 0.056+/-0.046 (Group SP), 0.089+/-0.048 (Group SA) and 0.058+/-0.049 (Group SB). The detection limit was 0.010 ng/ml. The correlations between the values in serum (Group SE) and in saliva were: r=0.77, p<0.05 (Group SP); r=0.62, p<0.05 (Group SA); r=0.70, p<0.05 (Group SB). The saliva values corresponding to the serum cut-off point of 3 ng/ml upper limit of normal values were in ng/ml 0.13 (Group SP), 0.16 (Group SA) and 0.11 (Group SB). In conclusion, 17-hydroxyprogesterone determinations in saliva using commercially available RIAs primarily developed for serum, is a reliable and easy to perform procedure. The three different methods of saliva collection showed 17-hydroxyprogesterone concentrations to have good agreement.     

U‐shaped response Unifies views on temperature dependency of stoichiometric requirements

Temperature and nutrient availability, which are major drivers of consumer performance, are dramatically affected by global change. To date, there is no consensus on whether warming increases or decreases consumer needs for dietary carbon (C) relatively to phosphorus (P), thus hindering predictions of secondary production responses to global change. Here, we investigate how the dietary C:P ratio optimising consumer growth (TER_C:P: Threshold Elemental Ratio) changes along temperature gradients by combining a temperature‐dependent TER_C:P model with growth experiments on Daphnia magna. Both lines of evidence show that the TER_C:P response to temperature is U‐shaped. This shape indicates that consumer nutrient requirements can both increase or decrease with increasing temperature, thus reconciling previous contradictive observations into a common framework. This unified framework improves our capacity to forecast the combined effects of nutrient cycle and climatic alterations on invertebrate production.