Polar and non-polar species of the protozoan ciliate Euplotes behave differently in response to environmental oxidative stress

Polar coastal seawaters are saturated by high oxygen concentrations, which impose very effective adaptive strategies to strive against a continuous environmental oxidative stress. We studied these strategies in Euplotes nobilii (Ciliophora: Spirotrichea), a ciliate species dwelling in Antarctic and Arctic coastal seawaters, in comparison with Euplotes raikovi, a sister species living in temperate seawaters. Cell samples of the two species were exposed to hydrogen peroxide (H2O2)-induced oxidative stress and analyzed for their survival rates and levels of expression of the genes encoding the enzyme methionine-sulfoxide reductase (Msr) A, which restores oxidized methionines (in their S form) of damaged proteins to the status of functional methionines. While 6 h of exposure to a 750-µM concentration of H2O2 did not affect E. nobilii viability, these conditions were lethal to E. raikovi. In correlation with this inter-specific difference in the cell survival to oxidative stress, the MsrA-coding genes of the two species showed different mechanisms of expression: constitutive in E. nobilii, elicited by induction in E. raikovi

Brain oscillations in cognitive control: a cross-sectional study with a spatial Stroop task

An important aspect of cognitive control is the ability to overcome interference, by boosting the processing of task-relevant information while suppressing the irrelevant information. This ability is affected by the progressive cognitive decline observed in aging. The aims of this study were to shed light on the neural spectral dynamics involved in interference control and to investigate age-dependent differences in these dynamics. For these reasons two samples of participants of different ages (23 younger and 20 older adults, age range=[18 35] and [66 82], respectively) were recruited and administered a spatial Stroop task while recording electroencephalographic activity. Scalp- and source-based time-frequency analyses revealed a main role of theta and beta frequencies in interference control. Specifically, for the theta band, we found age-dependent differences both for early event-related spectral perturbation (ERSP) Stroop effects at the source level \u2013 which involved dorsomedial and dorsolateral prefrontal cortices \u2013 and for related brain-behaviour correlations. This ERSP Stroop effect in theta was greatly reduced in magnitude in the older group and, differently from what observed in younger participants, it was not correlated with behavioural performance. These results suggest an age-dependent impairment of the theta-related mechanism signalling the need of cognitive control, in line with existing findings. We also found age-related differences in ERSP and source spectral activity involving beta frequencies. Indeed, younger participants showed a specific ERSP Stroop effect in beta \u2013 with the main involvement of left prefrontal cortex \u2013 whereas the pattern of older participants was delayed in time and spread bilaterally over the scalp. This study shows clear age-related differences in the neural spectral correlates of cognitive control. These findings open new questions about the causal involvement of specific oscillations in different cognitive processes and may inspire future interventions against age-related cognitive decline

lmeEEG: Mass linear mixed-effects modeling of EEG data with crossed random effects

Background: Mixed-effects models are the current standard for the analysis of behavioral studies in psycholinguistics and related fields, given their ability to simultaneously model crossed random effects for subjects and items. However, they are hardly applied in neuroimaging and psychophysiology, where the use of mass univariate analyses in combination with permutation testing would be too computationally demanding to be practicable with mixed models. New method: Here, we propose and validate an analytical strategy that enables the use of linear mixed models (LMM) with crossed random intercepts in mass univariate analyses of EEG data (lmeEEG). It avoids the unfeasible computational costs that would arise from massive permutation testing with LMM using a simple solution: removing random-effects contributions from EEG data and performing mass univariate linear analysis and permutations on the obtained marginal EEG. Results: lmeEEG showed excellent performance properties in terms of power and false positive rate. Comparison with existing methods: lmeEEG overcomes the computational costs of standard available approaches (our method was indeed more than 300 times faster). Conclusions: lmeEEG allows researchers to use mixed models with EEG mass univariate analyses. Thanks to the possibility offered by the method described here, we anticipate that LMM will become increasingly important in neuroscience. Data and codes are available at osf.io/kw87a. The codes and a tutorial are also available at github.com/antovis86/lmeEEG

Francisella-like endosymbionts, potentially harmful to human health, are transported by the universally distributed species of the ciliate Euplotes.

Genome analyses of wild-type strains of two ecologically separated Euplotes species, E. raikovi living in temperate sea waters and E. petzi living in the polar seas, revealed that both host bacteria in their cytoplasm. These bacteria have been identified with facultative intracellular gamma-proteobacteria of the genus Francisella, which includes a number of closely related species well known as extremely infectious to a great variety of organisms. Francisella tularensis, with its four subspecies, is a specialized intracellular pathogen capable of infecting both invertebrate and vertebrate hosts, humans included; F. noatunensis is the etiological agent of the fish disease known as francisellosis, and its two subspecies well adapt to different temperatures of their hosts; the Francisella-like endosymbionts Wolbachia persica, together with the freely living generalists F. philomiragia and F. novicida cause diseases in humans with a compromised immune system. The Francisella endosymbionts of E. raikovi and E. petzi have been successfully isolated and their genomes completely sequenced. They are genetically distant from one another and form two different clades in the Francisella phylogenetic tree, which are distinct from the all other well-established Francisella clades. The finding that Francisella has equally colonized polar and temperate-water species provides evidence that this bacterium is more common and widespread than previously hypothesized, and confirms that free-living Euplotes species and ciliates in general, with their worldwide distribution, may represent a natural reservoir of Francisella in every aquatic environment

Effects of Two Commercial Diets on Several Reproductive Parameters in Bitches: Note One-From Estrous Cycle to Parturition

The close link between nutrition management and reproductive efficiency is well known, but there is very little data available concerning this topic in canine species. The present study aimed to compare the effect of two different diets upon the follicular period and gestation in bitches. Eighteen pluriparus medium and large size bitches were recruited and divided into control (CTR) and experimental (EX) groups and fed, respectively, with a commercial kibble diet and a specially formulated diet from two months before the expected onset of proestrus up to the end of the trial. It was possible to observe how the EX group had a better clinical presentation of the estrous phase, a higher number of ovarian follicles (p < 0.05), a lower percentage of fetal resorption (p < 0.05), and lower oxidative status, expressed by d-ROMs (p < 0.01), at the moment of pregnancy diagnosis compared to CTR group. Moreover, the EX group showed a lower fetal resorption rate and higher litter size (p < 0.05). These results highlight how a diet characterized by high protein and fat content and richer in essential fatty acids can improve reproductive performance in dogs

Effects of Two Commercial Diets on Several Reproductive Parameters in Bitches: Note Two-Lactation and Puppies' Performance

The study aimed to compare two diets, Control (CTR) and Experimental (EX) (mainly differing as regards their ingredients, energy, and protein contents) administered to medium and large-sized bitches from two months before the expected proestrus and up to 30 days after delivery on mothers’ weight, body condition score, litter size, milk quality, and puppies’ growth. No differences were found for body weight during pregnancy, even if the BCS after delivery was significantly (p < 0.01) higher in the EX group than in the CTR one. Concerning the size effect, the percentage of weight gain on the initial body weight was double in medium-sized dogs compared to large dogs (p < 0.01). The number of puppies per litter was significantly higher (p < 0.05) for the EX group compared to the CTR one. Concerning puppies’ weight, the CTR group showed a significantly (p < 0.01) higher body weight from the 21st day of life due to the significant (p < 0.01) higher daily weight gain during the suckling period. Considering the performance of bitches and puppies, both diets seem useful for these stages of their lives. In fact, after 30 days of lactation, all tested bitches showed a healthy status and both the percentage of newborns mortality and puppies’ growth kinetics fell into the normal physiological range for the species

Complete Genome Sequence of Francisella endociliophora Strain FSC1006, Isolated from a Laboratory Culture of the Marine Ciliate Euplotes raikovi

A strain of Francisella endociliophora was isolated from a laboratory culture of the marine ciliate Euplotes raikovi. Here, we report the complete genome sequence of the bacterial strain FSC1006 (Francisella Strain Collection, Swedish Defence Research Agency, Umeå, Sweden)

Functional Interplay Between Posterior Parietal Cortex and Hippocampus During Detection of Memory Targets and Non-targets

© Copyright © 2020 Ciaramelli, Burianová, Vallesi, Cabeza and Moscovitch. Posterior parietal cortex is frequently activated during episodic memory retrieval but its role during retrieval and its interactions with the hippocampus are not yet clear. In this fMRI study, we investigated the neural bases of recognition memory when study repetitions and retrieval goals were manipulated. During encoding participants studied words either once or three times, and during retrieval they were rewarded more to detect either studied words or new words. We found that (1) dorsal parietal cortex (DPC) was more engaged during detection of items studied once compared to three times, whereas regions in the ventral parietal cortex (VPC) responded more to items studied multiple times; (2) DPC, within a network of brain regions functionally connected to the anterior hippocampus, responded more to items consistent with retrieval goals (associated with high reward); (3) VPC, within a network of brain regions functionally connected to the posterior hippocampus, responded more to items not aligned with retrieval goals (i.e., unexpected). These findings support the hypothesis that DPC and VPC regions contribute differentially to top-down vs. bottom-up attention to memory. Moreover, they reveal a dissociation in the functional profile of the anterior and posterior hippocampi

Ready ... Go: Amplitude of the fMRI Signal Encodes Expectation of Cue Arrival Time

What happens when the brain awaits a signal of uncertain arrival time, as when a sprinter waits for the starting pistol? And what happens just after the starting pistol fires? Using functional magnetic resonance imaging (fMRI), we have discovered a novel correlate of temporal expectations in several brain regions, most prominently in the supplementary motor area (SMA). Contrary to expectations, we found little fMRI activity during the waiting period; however, a large signal appears after the “go” signal, the amplitude of which reflects learned expectations about the distribution of possible waiting times. Specifically, the amplitude of the fMRI signal appears to encode a cumulative conditional probability, also known as the cumulative hazard function. The fMRI signal loses its dependence on waiting time in a “countdown” condition in which the arrival time of the go cue is known in advance, suggesting that the signal encodes temporal probabilities rather than simply elapsed time. The dependence of the signal on temporal expectation is present in “no-go” conditions, demonstrating that the effect is not a consequence of motor output. Finally, the encoding is not dependent on modality, operating in the same manner with auditory or visual signals. This finding extends our understanding of the relationship between temporal expectancy and measurable neural signals

Experimental Study of the Effects of Three Types of Meat on Endothelial Function in a Group of Healthy Volunteers

Background: There is a relationship between atherosclerotic risk factors and increased vascular production of reactive oxygen species (ROS). Oxidized LDL and ROS may directly cause endothelial dysfunction by reducing endothelial nitric oxide (NO) bioavailability. The semi-essential amino acid L-arginine is the only substrate for NO synthesis in vascular endothelial cells. Therefore, this amino acid improves endothelial function and plays a role in the prevention and/or treatment of multiple cardiovascular diseases: atherosclerosis, hypertension, diabetes and so on. To determine the effects of three different protein matrices (250 g Fillet of Beef, FB; Chicken Raised on the Ground, CRG; Free-Range Chicken, FRC) with a known content of arginine on the cardiovascular workload, vascular compliance and urinary excretion of some parameters of endothelial function as TGF–Beta, NO (nitrate e nitrite) in a group of healthy volunteers. Materials and methods: We enrolled 10 men to study the behavior of Systolic, Diastolic, Mean, and Pulse Blood Pressure, of Vascular Resistances, of Macro and Micro Vascular Elasticity, of urinary excretion of TGF-β and Nitric Oxide as ratio of creatinine before and after two hours of each meal. The cardiovascular parameters are determined by HDI/Pulse Wave CR 2000 (Hypertension Diagnostic Inc, Eagan, MN); TGF-β is analysed by Elisa method (R&D Systems) and NO by colorimetric method (Cayman). Results and Conclusion: The protein meal packed with CRG causes a significant decrease in diastolic blood pressure mean pressure and vascular resistance in urinary excretion of TGF. FB resulted in a significant decrease in vascular resistance and urinary excretion of NO, while significantly increasing the Pulse Pressure, heart rate and urinary excretion of TGF-β. FRC resulted in a significant reduction of macrovascular elasticity; increase the urinary excretion of TGF and Pulse Pressure. We can conclude that CRG meat looks better both in terms of metabolic and cardiovascular load especially at endothelial level