Modulation of intracellular calcium and proliferative activity of invertebrate and vertebrate cells by ethylene

Background  

Ethylene is a widely distributed alkene product which is formed enzymatically (e.g., in plants) or by photochemical reactions (e.g., in the upper oceanic layers from dissolved organic carbon). This gaseous compound was recently found to induce in cells from the marine sponge Suberites domuncula, an increase in intracellular Ca²⁺ level ([Ca²⁺]_i) and an upregulation of the expression of two genes, the potential ethylene-responsive gene, SDERR, and a Ca²⁺/calmodulin-dependent protein kinase.     

Lipids of different phytoplankton groups differ in sensitivity to degradation: Implications for carbon export

The future of life on Earth depends on how the ocean might change, as it plays an important role in mitigating the effects of global warming. The main role is played by phytoplankton. Not only are phytoplankton the base of the oceans' food web, but they also play an important role in the biological carbon pump (BCP), the process of forming organic matter (OM) and transporting it to the deep sea, representing a sink of atmospheric CO₂. Lipids are considered important vectors for carbon sequestration. A change in the phytoplankton community composition as a result of ocean warming is expected to affect the BCP. Many predictions indicate a dominance of small at the expense of large phytoplankton. To gain insight into interplay between the phytoplankton community structure, lipid production and degradation, and adverse environmental conditions, we analyzed phytoplankton composition, particulate organic carbon (POC) and its lipid fraction in the northern Adriatic over a period from winter to summer at seven stations with a gradient of trophic conditions. We found that at high salinity and low nutrient content, where nanophytoplankton prevailed over diatoms, the newly fixed carbon is substantially directed toward the synthesis of lipids. Lipids produced by nanophytoplankton, coccolithophores, and phytoflagellates, are more resistant to degradation than those produced by diatoms. The difference in lipid degradability is discussed as a difference in the size of the cell phycosphere. We hypothesize that the lipids of nanophytoplankton are less degradable due to the small phycosphere with a poorer bacterial community and consequently a lower lipid degradation rate compared with diatoms. The lipid chemical composition of the different phytoplankton groups could have a different susceptibility to degradation. Results suggest a successful lipid carbon sink of nanophytoplankton and, thus, a negative feedback on global warming.     

The impact of obesity to antioxidant defense parameters in adolescents with increased cardiovascular risk

BackgroundThe goal of this study was to assess the oxidative stress status through the values of antioxidant defense parameters: superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and total antioxidant status (TAS), as well as cardiovascular risk factors (total cholesterol, LDL-cholesterol, VLDL-cholesterol, non-HDL-cholesterol and triglycerides), anthropometric parameters (Body mass index-BMI, waist circumference-WC, hipp circumferemce-HC, waist-to-hipp ratio-WHR and inflammatory markers (high sensitive C-reactive protein) in a group of obese adolescents.MethodsA total of 238 students of both sexes, age of 22.32 ± 1.85 yr. were included in the study. According to the values of BMI lower and higher than 25 kg/m2 and WC higher and lower than 94 cm (males)/80 cm (females) the tested group of students was divided into 2 subgroups: Group 1 (increased risk for CVD) and Group 2 (lower risk for CVD).ResultsSignificantly reduced SOD and GPx with increased GR, TAS, inflammatory and lipoprotein parameters were obtained in Group 1 compared to Group 2. Significant positive association of hsCRP (OR:1.41; 95%CI 1.08-1.83; P=0.007), TAS (OR:827.2; 95%CI 19.27-35498; P=0.007) and GR (OR:1.13; 95%CI 1.05-1.21; P=0.002) and negative association of GPx (OR:0.97; 95%CI 0.94-1.003; P=0.043) and HDL-cholesterol (OR:0.41; 95%CI 0.176-0.963; P=0.0014) with cardiovascular risk factors were found in obese students. According to the ROC analysis GR>44.8 U/L, TAS>1.35 mmol/L, hsCRP>1.71 mg/L and HDL-cholesterol <1.13 mmol/L have sufficient predictive ability for cardiovascular disease in obese students.ConclusionsSignificant association of antioxidant defense parameters with anthropometric, lipid and inflammatory markers in obese students with increased cardiovascular risk suggest that screening of these parameters is necessary and highly recommended.     

Follicular fluid vascular endothelial growth factor is associated with type of infertility and interferon alpha correlates with endometrial thickness in natural cycle in vitro fertilization

The aim of this study was to analyse the presence of vascular endothelial growth factor (VEGF) and interferon alpha (IFN-α) in the follicular fluid (FF) and their possible influence, as pro-angiogenic or anti-angiogenic factors, on in vitro fertilization outcome. The concentrations of VEGF and IFN-α were correlated with oocyte and embryo quality, concentrations of hormones in the serum, perifollicular blood flow and endometrial thickness. VEGF was detected in all FF samples (median 706.6?pg/ml, range 182.9–6638?pg/ml). IFN-α was detected in 60% of the samples (median 6.5?pg/ml, range 0–79.4?pg/ml), while in 40% of the samples its levels were below the test detection limit. VEGF and IFN-α concentrations did not correlate with the cause of infertility, concentrations of FSH, LH, E2 and prolactin, oocyte or embryo quality. Significantly higher concentrations of VEGF have been found in women with primary compared with secondary infertility (p?=?0.011, Mann Whitney test). The concentrations of VEGF and IFN-α did not correlate with the resistance index (RI) on days of hCG administration, follicular aspiration and embryo transfer. However, the concentrations of IFN-α correlated with endometrial thickness on the day of embryo transfer (Spearman correlation coefficient ρ?=?0.4107; P?<?0.05) but not on days of hCG administration and follicular aspiration. The mechanism of VEGF association with the previous ability of having a child needs to be clarified in future studies. The results of this study indicate a possible role of IFN-α in pathways of endometrial remodelling.     

Past and future climate-driven shifts in the distribution of a warm-adapted bird species,the European Roller Coracias garrulus

ABSTRACT

Capsule: The distribution range of the European Roller Coracias garrulus has undergone large changes over geological times, but although the species is warm-adapted, the human induced climate change is predicted to affect negatively the range of the currently large populations.

Aim: Information on species-specific vulnerability to climate change is crucial not only for designing interventions and setting conservation goals, but also to inform conservation decision-making. Our goal was to map climate suitability for the European Roller in the Western Palaearctic under current climate, and for past (last glacial maximum and mid-Holocene) and future (2050 and 2070) climate scenarios.

Methods: We used MaxEnt for species distribution modelling based on the reconstructed distribution map of the species.

Results: Our results suggest that during glacial periods Rollers persisted in small southern refugia, and then spread and colonized northern latitudes during the mid-Holocene. In the future, our models forecast a shift in climatically suitable range towards northern latitudes and an overall small range contraction (4.5–5.5%). Warmer temperatures will increase climate suitability in northern countries where the species is currently declining or became locally extinct. On the other hand, wide suitable areas under current climatic conditions are predicted to become unsuitable in the future (35–38% by 2050 and 2070, respectively), significantly impacting large populations such as those in Romania, Spain, Bulgaria and Hungary. French and Italian populations are identified to be future key populations for Roller conservation.

Conclusions: Our findings suggest that future climate changes will likely amplify the impacts of existing threats on the majority of large European Roller populations in Europe.     

Heterologous Escherichia coli Expression, Purification and Characterization of the GrmA Aminoglycoside-Resistance Methyltransferase

The mechanism of resistance to aminoglycosides based on methylation of their target, 16S rRNA, was until recently described only in antibiotic producing microorganisms. However, equivalent methyltransferases have now also been identified among numerous clinical Gram-negative pathogenic isolates. We have cloned, expressed, and purified GrmA, the aminoglycoside-resistance methyltransferase from Micromonospora purpurea, producer of gentamicin complex. Two vectors were created that express protein with an N-terminal 6× histidine tag with and without an enterokinase recognition producing proteins His₆-EK-GrmA and His₆-GrmA, respectively. The activity of both recombinant proteins was demonstrated in vivo. After optimized expression and native purification both protein variants proved to be active in in vitro methylation assays. This work lays a foundation for future detailed biochemical, structural and pharmacological studies with this member of an important group of aminoglycoside-resistance enzymes.     

Sperm storage and degradation in the spermathecae of the salamander Eurycea Cirrigera

Spermathecae are exocrine glands in the roof of the female cloaca that store sperm. Cytological and histochemical data indicate that the one type of secretion into the lumen is a glycoprotein. After a period of stasis in the summer, production of the secretion is initiated in the fall, coincident with an increase in ovarian follicular size. By the time of maximal follicular development and most intense mating activity in March and April, the spermathecal epithelium is filled with secretory granules. The secretory material is released into the lumen, enveloping the sperm. Many sperm remain in the spermathecae after oviposition, and most of these sperm are degraded in the spermathecal epithelium or pass through interruptions in the spermathecal walls caused by desquamation. Sperm in contact with the stromal environment are phagocytized by leukocytes. Some sperm, however, may survive in the lumen until at least the following fall. These sperm retain normal cytology, but whether or not they remain fertile and intact until a subsequent ovipository cycle is unknown.