Ferulic Acid Improves Cognitive Skills Through the Activation of the Heme Oxygenase System in the Rat

Over the last years, many studies reported on the antioxidant effects of ferulic acid (FA) in preclinical models of dementia through the activation of the heme oxygenase/biliverdin reductase (HO/BVR) system. However, only a few studies evaluated whether FA could improve neurological function under milder conditions, such as psychological stress. The aim of this study was to investigate the effects of FA (150 mg/kg intraperitoneal route) on cognitive function in male Wistar rats exposed to emotional arousal. Animals were randomly assigned to two experimental groups, namely not habituated or habituated to the experimental context, and the novel object recognition test was used to evaluate their cognitive performance. The administration of FA significantly increased long-term retention memory in not habituated rats. Ferulic acid increased the expression of HO-1 in the hippocampus and frontal cortex of not habituated rats only, whereas HO-2 resulted differently modulated in these cognitive brain areas. No significant effects on either HO-1 or HO-2 or BVR were observed in the cerebellum of both habituated and not habituated rats. Ferulic acid activated the stress axis in not habituated rats, as shown by the increase in hypothalamic corticotrophin-releasing hormone levels. Pre-treatment with Sn-protoporphyrin-IX [0.25 μmol/kg, intracerebroventricular route (i.c.v.)], a well-known inhibitor of HO activity through which carbon monoxide (CO) and biliverdin (BV) are generated, abolished the FA-induced improvement of cognitive performance only in not habituated rats, suggesting a role for HO-derived by-products. The CO-donor tricarbonyldichlororuthenium (II) (30 nmol/kg i.c.v.) mimicked the FA-related improvement of cognitive skills only in not habituated rats, whereas BV did not have any effect in any group. In conclusion, these results set the stage for subsequent studies on the neuropharmacological action of FA under conditions of psychological stress.     

On the aggregation of bilirubinoids in solution as evidenced by VCD and ECD spectroscopy and DFT calculations

Vibrational and electronic circular dichroism (VCD and ECD) spectra of 3 optically active bilirubin analogs with propionic acid groups replaced by (1) 1‐(S)‐methylpropyl groups, (2) 3‐acetoxy‐1‐(S)‐methylpropyl groups, and (3) 1‐(S)‐2‐(R)‐dimethyl‐2‐(methoxycarbonyl)ethyl groups have been recorded at different concentrations in chloroform. The aliphatic chains attached to C‐8 and C‐12 of the 3 chosen mesobilirubins were modified so as to possess no OH group. The variation of the VCD spectra with concentration is consistent with the formation of dimers at high concentration. Density functional theory and time‐dependent density functional theory calculations on monomeric and dimeric forms support such a conclusion. Comparing with previous VCD (ECD) and IR (UV) studies of other mesobilirubin molecules, it is concluded that here, the key feature for aggregation is the missing OH groups on the propionic acid chains. The latter, in synergy with the polar groups of lactam moieties, appear to be involved in intramolecular phenomena and thus favor monomeric forms. Investigation of ECD and UV spectra of the same compounds in mixed DMSO/chloroform solutions provide further clues to the proposed picture.     

Toward a general mixed quantum/classical method for the calculation of the vibronic ECD of a flexible dye molecule with different stable conformers: Revisiting the case of 2,2,2‐trifluoro‐anthrylethanol

We extend a recently proposed mixed quantum/classical method for computing the vibronic electronic circular dichroism (ECD) spectrum of molecules with different conformers, to cases where more than one hindered rotation is present. The method generalizes the standard procedure, based on the simple Boltzmann average of the vibronic spectra of the stable conformers, and includes the contribution of structures that sample all the accessible conformational space. It is applied to the simulation of the ECD spectrum of (S)‐2,2,2‐trifluoroanthrylethanol, a molecule with easily interconvertible conformers, whose spectrum exhibits a pattern of alternating positive and negative vibronic peaks. Results are in very good agreement with experiment and show that spectra averaged over all the sampled conformational space can deviate significantly from the simple average of the contributions of the stable conformers. The present mixed quantum/classical method is able to capture the effect of the nonlinear dependence of the rotatory strength on the molecular structure and of the anharmonic couplings among the modes responsible for molecular flexibility. Despite its computational cost, the procedure is still affordable and promises to be useful in all cases where the ECD shape arises from a subtle balance between vibronic effects and conformational variety.     

A new insight into the oxidative mechanism of caffeine and related methylxanthines in aprotic medium: May caffeine be really considered as an antioxidant?

Background

Antioxidant properties have been recently suggested for caffeine that seems showing protective effects against damages caused by oxidative stress. In particular, a HO scavenging activity has been ascribed to caffeine. Even if the oxidation of caffeine has been widely studied, the antioxidant mechanism is still far to be understood.

Denitrification in a meromictic lake and its relevance to nitrogen flows within a moderately impacted forested catchment

We analysed the spatial and temporal variability of benthic nitrogen fluxes and denitrification rates in a sub-alpine meromictic lake (Lake Idro, Italy), and compared in-lake nitrogen retention and loss with the net anthropogenic nitrogen inputs to the watershed. We hypothesized a low nitrogen retention and denitrification capacity due to meromixis. This results from nitrate supply from the epilimnion slowing down during stratification and oxygen deficiency inhibiting nitrification and promoting ammonium recycling and its accumulation. We also hypothesized a steep vertical gradient of sedimentary denitrification capacity, decreasing with depth and oxygen deficiency. These are important and understudied issues in inland waters, as climate change and direct anthropic pressures may increase the extent of meromixis. Nearshore sediments had high denitrification rates (87 mg m^?2 day^?1) and efficiency (~ 100%), while in the monimolimnion denitrification was negligible. The littoral zone, covering 10% of the lake surface, contributed ~50% of total denitrification, while the monimolimnion, which covered 70% of the sediment surface, contributed to < 13% of total denitrification. The persistent and expanding meromixis of Lake Idro is expected to further decrease its nitrogen removal capacity (31% of the incoming nitrogen load) compared to what has been measured in other temperate lakes. Values up to 60% are generally reported for other such lakes. Results of this study are relevant as the combination of anthropogenic pressures, climate change and meromixis may threaten the nitrogen processing capacity of lakes.     

StAR protein and steroidogenic enzyme expressions in the rat Harderian gland

The Harderian gland (HG) of the rat (Rattus norvegicus) secretes copious amounts of lipids, such as cholesterol. Here we report a study of the expressions of the StAR protein and key steroidogenic enzymes in the HG of male and female rats. The objective of the present investigation was to ascertain (a) whether the rat HG is involved in steroid production starting with cholesterol, and (b) whether the pattern of gene and protein expressions together with the enzymatic activities display sexual dimorphism. The results demonstrate, for the first time, the expression of StAR gene and protein, and Cyp11a1, Hsd3b1, Hsd17b3, Srd5a1, Srd5a2 and Cyp19a1 genes in the rat HG. StAR mRNA and protein expressions were much greater in males than in females. Immunohistochemical analysis demonstrated a non-homogeneous StAR distribution among glandular cells. Hsd17b3 and Cyp19a1 mRNA levels were higher in males than in females, whereas Srd5a1 mRNA levels were higher in females than in males. No significant differences were observed in mRNA levels of Cyp11a1, Hsd3b1 and Srd5a2 between sexes. Furthermore, the in vitro experiments demonstrated a higher 5α-reductase activity in the female as compared to the male HG vice versa a higher P450 aro activity in males as compared to females. These results suggest that the Harderian gland can be classified as a steroidogenic tissue because it synthesizes cholesterol, expresses StAR and steroidogenic enzymes involved in both androgen and estrogen synthesis. The dimorphic expression and activity of the steroidogenic enzymes may suggest sex-specific hormonal effects into the HG physiology.     

Summary of the morphological and ecological traits of Central European dung beetles

Ecological, morphological and life‐history traits have been increasingly used in community ecology during the last decade. Dung beetles represent a model group of insects frequently used in studies of landscape ecology and grassland management. Their body sizes and nesting behavioral traits are regularly used to help understand ecological processes at the community level. However, information on their seasonal activity, wing morphometry and dung specialization is sparse in published reports, or is simply not available yet. We thus compiled a comprehensive list of the morphological and ecological traits of Central European dung beetles (Geotrupidae, Scarabaeidae and Aphodiidae). We gathered information from published works and, for the first time, took morphometric measurements of wings. We provide a database of 12 traits for all 100 dung beetle species occurring in Central Europe. Most species are not restricted to one specific dung type, and the most frequently used dung types are sheep/goat, cattle and horse dung, which are almost equally exploited by 90, 89 and 87 species, respectively. More than one‐third of all species are active in winter, and the number of active species is the highest in June. The wing morphometry shows a high variation and is largely determined by the family identity; the ratio of elytron length to wing area is the largest in Aphodiidae but the smallest in Geotrupidae. Our database is the first standardized set of information for Central European dung beetles and can be used in future trait‐based studies focusing on the ecology and conservation of these beetles.     

The impact of endogenous content,replicates and pooling on genome capture from faecal samples

Target‐capture approach has improved over the past years, proving to be very efficient tool for selectively sequencing genetic regions of interest. These methods have also allowed the use of noninvasive samples such as faeces (characterized by their low quantity and quality of endogenous DNA) to be used in conservation genomic, evolution and population genetic studies. Here we aim to test different protocols and strategies for exome capture using the Roche SeqCap EZ Developer kit (57.5 Mb). First, we captured a complex pool of DNA libraries. Second, we assessed the influence of using more than one faecal sample, extract and/or library from the same individual, to evaluate its effect on the molecular complexity of the experiment. We validated our experiments with 18 chimpanzee faecal samples collected from two field sites as a part of the Pan African Programme: The Cultured Chimpanzee. Those two field sites are in Kibale National Park, Uganda (N = 9) and Loango National Park, Gabon (N = 9). We demonstrate that at least 16 libraries can be pooled, target enriched through hybridization, and sequenced allowing for the genotyping of 951,949 exome markers for population genetic analyses. Further, we observe that molecule richness, and thus, data acquisition, increase when using multiple libraries from the same extract or multiple extracts from the same sample. Finally, repeated captures significantly decrease the proportion of off‐target reads from 34.15% after one capture round to 7.83% after two capture rounds, supporting our conclusion that two rounds of target enrichment are advisable when using complex faecal samples.