Are taxonomy details of relevance to ecologists? An example from microcopepods of the Red Sea

The marine microcopepod family Oncaeidae in the Red Sea has been the subject of comprehensive ecological studies over the past 15 years, providing for the first time insights into their community structure, vertical distribution and feeding ecology. Owing to taxonomic problems in species identification, however, many of the earlier ecological results were based on provisionally named species or morphotypes. A recent, ongoing taxonomic study of Red Sea Oncaeidae resulted in a considerable increase in the estimated numbers of species, since many of the species had not been described before. The present paper focuses on the potential significance of an improved taxonomic resolution of oncaeids with respect to various ecological aspects in this area, such as indicator species, community analysis and vertical distribution. The progress in our knowledge of the diversity of Red Sea Oncaeidae is summarized, including latest findings on the taxonomy and zoogeography of very small species (<0.5 mm), and the importance of sibling species in the family is pointed out. The south–north gradient in species diversity of Oncaeidae within the Red Sea appears to be greater than previously assumed, since several of the newly described species were restricted to the southern part. The number of endemic species among Red Sea oncaeids is very low, however, most of the new species being also recorded outside the Red Sea. New quantitative data on the abundance and vertical distribution of selected oncaeid siblings obtained during a recent cruise in the northern Red Sea are provided to exemplify the changes in the knowledge of oncaeid community structure attributable to the improved taxonomic resolution. The potential ecological importance of a more differentiated consideration of oncaeid species in marine microcopepod communities is discusse

Reactivation of the mitosis-promoting factor in postmitotic cardiomyocytes

Cardiomyocytes cease to divide shortly after birth and an irreversible cell cycle arrest is evident accompanied by the downregulation of cyclin-dependent kinase activities. To get a better understanding of the cardiac cell cycle and its regulation, the effect of functional recovery of the mitosis-promoting factor (MPF) consisting of cyclin B1 and the cyclin-dependent kinase Cdc2 was assessed in primary cultures of postmitotic ventricular adult rat cardiomyocytes ( ARC). Gene transfer into ARC was achieved using the adenovirus-enhanced transferrinfection system that was characterized by the absence of cytotoxic events. Simultaneous ectopic expression of wild-type versions of cyclin B1 and Cdc2 was sufficient to induce MPF activity. Reestablished MPF resulted in a mitotic phenotype, marked by an abnormal condensation of the nuclei, histone H3 phosphorylation and variable degree of decay of the contractile apparatus. Although a complete cell division was not observed, the results provided conclusive evidence that cell cycle-related events in postmitotic cardiomyocytes could be triggered by genetic intervention downstream of the G1/S checkpoint. This will be of importance to design novel strategies to overcome the proliferation arrest in adult cardiomyocytes

Stable isotope ratios of nitrogen and carbon as biomarkers of a vegan diet

Purpose Dietary biomarkers can potentially overcome the limitations of self-reported dietary data. While in ecology and archaeology, stable isotope ratios of carbon and nitrogen are widely used as biomarkers, this is not the case in nutrition research. Since the abundance of the 13C and the 15N isotope differ in food sources from plant and animal origin, stable isotope ratios of carbon and nitrogen (δ13C and δ15N) may differ in human biological material. Here, we investigated the stable isotope ratios of nitrogen and carbon in serum and urine from vegans and omnivores. Method Measurement of δ15N and δ13C in serum and 24 h urine was performed by Elemental Analyzer–Isotope Ratio Mass Spectrometer in the cross-sectional study “Risks and Benefits of a Vegan Diet”. The study included 36 vegans and 36 omnivores with a median age of 37.5 years (matched for age and sex), who adhered to their diet for at least 1 year. Results Both δ15N and δ13C were significantly lower in both the serum and 24 h urine of vegans compared to omnivores. δ15N either in serum or urine had 100% specificity and sensitivity to discriminate between vegans and omnivores. Specificity of δ13C was also > 90%, while sensitivity was 93% in serum and 77% in urine. Conclusion δ15N both in serum and urine was able to accurately identify vegans and thus appears to be a promising marker for dietary habits.publishedVersio

Effects of prolonged endotoxemia on liver, skeletal muscle and kidney mitochondrial function

INTRODUCTION: Sepsis may impair mitochondrial utilization of oxygen. Since hepatic dysfunction is a hallmark of sepsis, we hypothesized that the liver is more susceptible to mitochondrial dysfunction than the peripheral tissues, such as the skeletal muscle. We studied the effect of prolonged endotoxin infusion on liver, muscle and kidney mitochondrial respiration and on hepatosplanchnic oxygen transport and microcirculation in pigs. METHODS: Twenty anesthetized pigs were randomized to receive either endotoxin or saline infusion for 24 hours. Muscle, liver and kidney mitochondrial respiration was assessed. The cardiac output (thermodilution) and the carotid, superior mesenteric and kidney arterial, portal venous (ultrasound Doppler) and microcirculatory blood flow (laser Doppler) were measured, and systemic and regional oxygen transport and lactate exchange were calculated. RESULTS: Endotoxin infusion induced hyperdynamic shock and impaired the glutamate-dependent and succinate-dependent mitochondrial respiratory control ratio in the liver (glutamate, median (range) endotoxemia 2.8 (2.3–3.8) vs controls 5.3 (3.8–7.0); P < 0.001; succinate, endotoxemia 2.9 (1.9–4.3) vs controls 3.9 (2.6–6.3), P = 0.003). While the ADP added/oxygen consumed ratio was reduced with both substrates, the maximal ATP production was impaired only in the succinate-dependent respiration. Hepatic oxygen consumption and extraction, and the liver surface laser Doppler blood flow remained unchanged. Glutamate-dependent respiration in the muscle and kidney was unaffected. CONCLUSION: Endotoxemia reduces the efficiency of hepatic mitochondrial respiration but neither skeletal muscle nor kidney mitochondrial respiration, independent of regional and microcirculatory blood flow changes

Comparison of Five Oxidative Stress Biomarkers in Vegans and Omnivores from Germany and Finland

When the amount of reactive oxygen species produced by human metabolism cannot be balanced by antioxidants, this phenomenon is commonly referred to as oxidative stress. It is hypothesised that diets with high amounts of plant food products may have a beneficial impact on oxidative stress status. However, few studies have examined whether a vegan diet is associated with lower oxidative stress compared to an omnivorous diet. The present cross-sectional study aimed to compare the levels of five oxidative stress biomarkers in vegans and omnivores. Data of 36 vegans and 36 omnivores from Germany and of 21 vegans and 18 omnivores from Finland were analysed. HPLC coupled with mass spectrometry or fluorescence detection and ELISA methods were used to measure the oxidative stress biomarkers malondialdehyde (MDA), protein carbonyls and 3-nitrotyrosine in plasma and 8-hydroxy-2 '-deoxyguanosine (8-OHdG) and 8-iso-prostaglandin F2 alpha (8-iso-PGF2 alpha) in 24 h urine. Analyses of variance and covariance, considering potential confounders, were used. Vegans and omnivores showed no differences in MDA and protein carbonyl concentrations. In Finnish but not in German vegans, the concentrations of 3-nitrotyrosine were lower compared to those in omnivores (p = 0.047). In Germany, vegans showed lower excretion levels of 8-iso-PGF2 alpha than omnivores (p = 0.002) and with a trend also of 8-OHdG (p = 0.05). The sensitivity analysis suggests lower 8-iso-PGF2 alpha excretion levels in women compared to men, independently of the dietary group. The present study contributes to expanding our knowledge of the relationship between diet and oxidative stress and showed that 3-nitrotyrosine, 8-OHdG and 8-iso-PGF2 alpha tended to be lower in vegans. Furthermore, studies are recommended to validate the present findings.Peer reviewe

Comparison of Five Oxidative Stress Biomarkers in Vegans and Omnivores from Germany and Finland

When the amount of reactive oxygen species produced by human metabolism cannot be balanced by antioxidants, this phenomenon is commonly referred to as oxidative stress. It is hypothesised that diets with high amounts of plant food products may have a beneficial impact on oxidative stress status. However, few studies have examined whether a vegan diet is associated with lower oxidative stress compared to an omnivorous diet. The present cross-sectional study aimed to compare the levels of five oxidative stress biomarkers in vegans and omnivores. Data of 36 vegans and 36 omnivores from Germany and of 21 vegans and 18 omnivores from Finland were analysed. HPLC coupled with mass spectrometry or fluorescence detection and ELISA methods were used to measure the oxidative stress biomarkers malondialdehyde (MDA), protein carbonyls and 3-nitrotyrosine in plasma and 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-iso-prostaglandin F2α (8-iso-PGF2α) in 24 h urine. Analyses of variance and covariance, considering potential confounders, were used. Vegans and omnivores showed no differences in MDA and protein carbonyl concentrations. In Finnish but not in German vegans, the concentrations of 3-nitrotyrosine were lower compared to those in omnivores (p = 0.047). In Germany, vegans showed lower excretion levels of 8-iso-PGF2α than omnivores (p = 0.002) and with a trend also of 8-OHdG (p = 0.05). The sensitivity analysis suggests lower 8-iso-PGF2α excretion levels in women compared to men, independently of the dietary group. The present study contributes to expanding our knowledge of the relationship between diet and oxidative stress and showed that 3-nitrotyrosine, 8-OHdG and 8-iso-PGF2α tended to be lower in vegans. Furthermore, studies are recommended to validate the present findings

Comparison of Five Oxidative Stress Biomarkers in Vegans and Omnivores from Germany and Finland

When the amount of reactive oxygen species produced by human metabolism cannot be balanced by antioxidants, this phenomenon is commonly referred to as oxidative stress. It is hypothesised that diets with high amounts of plant food products may have a beneficial impact on oxidative stress status. However, few studies have examined whether a vegan diet is associated with lower oxidative stress compared to an omnivorous diet. The present cross-sectional study aimed to compare the levels of five oxidative stress biomarkers in vegans and omnivores. Data of 36 vegans and 36 omnivores from Germany and of 21 vegans and 18 omnivores from Finland were analysed. HPLC coupled with mass spectrometry or fluorescence detection and ELISA methods were used to measure the oxidative stress biomarkers malondialdehyde (MDA), protein carbonyls and 3-nitrotyrosine in plasma and 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-iso-prostaglandin F2α (8-iso-PGF2α) in 24 h urine. Analyses of variance and covariance, considering potential confounders, were used. Vegans and omnivores showed no differences in MDA and protein carbonyl concentrations. In Finnish but not in German vegans, the concentrations of 3-nitrotyrosine were lower compared to those in omnivores (p = 0.047). In Germany, vegans showed lower excretion levels of 8-iso-PGF2α than omnivores (p = 0.002) and with a trend also of 8-OHdG (p = 0.05). The sensitivity analysis suggests lower 8-iso-PGF2α excretion levels in women compared to men, independently of the dietary group. The present study contributes to expanding our knowledge of the relationship between diet and oxidative stress and showed that 3-nitrotyrosine, 8-OHdG and 8-iso-PGF2α tended to be lower in vegans. Furthermore, studies are recommended to validate the present findings