Molecular mechanisms of zinc toxicity in the potworm Enchytraeus crypticus, analysed by high-throughput gene expression profiling

Zinc (Zn) is known to be relatively toxic to some soil-living invertebrates including the ecologically important enchytraeid worms. To reveal the molecular mechanisms of zinc toxicity we assessed the gene expression profile of Enchytraeus crypticus (Enchytraeidae), exposed to the reproduction effect concentrations EC10 and EC50, over 4 consecutive days, using a high-throughput microarray (species customized). Three main mechanisms of toxicity to Zn were observed: 1) Zn trafficking (upregulation of zinc transporters, a defence response to regulate the cellular zinc level), 2) oxidative stress (variety of defence mechanisms, triggered by Reactive Oxygen Species (ROS)), and 3) effects on the nervous system (possibly the primary lesion explaining the avoidance behaviour and also why enchytraeids are relatively susceptible to Zn). The adverse outcome at the organism level (reproduction EC50) could be predicted based on gene expression (male gonad development, oocyte maturation), with Zn at the EC50 affecting processes related to higher stress levels. The gene expression response was time-dependent and reflected the cascade of events taking place over-time. The 1 to 4 days of exposure design was a good strategy as it captured the time for sequence of events towards zinc adverse outcomes in E. crypticus

The Effects of Heparan Sulfate Infusion on Endothelial and Organ Injury in a Rat Pneumosepsis Model

Septic shock is characterized by endothelial dysfunction, leading to tissue edema and organ failure. Heparan sulfate (HS) is essential for vascular barrier integrity, possibly via albumin as a carrier. We hypothesized that supplementing fluid resuscitation with HS would improve endothelial barrier function, thereby reducing organ edema and injury in a rat pneumosepsis model. Following intratracheal inoculation with Streptococcus pneumoniae, Sprague Dawley rats were randomized to resuscitation with a fixed volume of either Ringer’s Lactate (RL, standard of care), RL supplemented with 7 mg/kg HS, 5% human albumin, or 5% human albumin supplemented with 7 mg/kg HS (n = 11 per group). Controls were sham inoculated animals. Five hours after the start of resuscitation, animals were sacrificed. To assess endothelial permeability, 70 kD FITC-labelled dextran was administered before sacrifice. Blood samples were taken to assess markers of endothelial and organ injury. Organs were harvested to quantify pulmonary FITC-dextran leakage, organ edema, and for histology. Inoculation resulted in sepsis, with increased lactate levels, pulmonary FITC-dextran leakage, pulmonary edema, and pulmonary histologic injury scores compared to healthy controls. RL supplemented with HS did not reduce median pulmonary FITC-dextran leakage compared to RL alone (95.1 CI [62.0–105.3] vs. 87.1 CI [68.9–139.3] µg/mL, p = 0.76). Similarly, albumin supplemented with HS did not reduce pulmonary FITC-dextran leakage compared to albumin (120.0 [93.8–141.2] vs. 116.2 [61.7 vs. 160.8] µg/mL, p = 0.86). No differences were found in organ injury between groups. Heparan sulfate, as an add-on therapy to RL or albumin resuscitation, did not reduce organ or endothelial injury in a rat pneumosepsis model. Higher doses of heparan sulfate may decrease organ and endothelial injury induced by shock.</p

Electrophysiological measures of conflict detection and resolution in the Stroop task

Conflict detection and resolution is crucial in a cognitive task like the Stroop task. Previous studies have identified an early negativity component (Ninc) as a prominent marker of Stroop conflict in event-related potentials (ERPs). However, to what extent this ERP component reflects conflict detection and/or resolution is still unclear. Here, we report a Stroop task in which the stimulus onset asynchrony (SOA) of color and word stimuli presentation was manipulated in order to disentangle the roles of conflict detection and conflict resolution in generating Stroop-related ERP components. Separating the word from the color information gives us precise control over the timing of conflict. If the Ninc is related with conflict resolution it should be absent when the word appears during response preparation, as in a long-latency positive SOA. Our data shows that the Ninc occurs in all SOAs, even after a response has been made, supporting its role in the detection of stimulus conflict rather than conflict resolution. The use of SOA manipulation therefore allows for the examination of a wider temporal spectrum of interference in order to specify the functions of this conflict-related component. These results provide insight into the neural signatures of conflict processes, and have implications for models of cognitive control mechanisms in the brain

When to inseminate the cow? Insemination, ovulation and fertilization in dairy cattle

Keywords: dairy cattle; oestrus; behaviour; pedometer; reproductive hormones; ovulation time; insemination strategyIn dairy practice, calving rates after first insemination are often less than 50%. Part of this low percentage might be explained by wrongly timed inseminations. The aim was to establish the relationship between various oestrus characteristics and ovulation time in order to investigate whether these oestrus characteristics could predict ovulation time and to study the consequences of variation in the interval between insemination and ovulation on the success of fertilization and embryonic characteristics. The ultimate goal of the project was to come to an optimal insemination strategy that can be used in practice. The relationship between behavioural oestrous signs, changes in activity (measured by pedometers) and progesterone profiles and time of ovulation were. It was shown that monitoring progesterone profiles was not suitable to predict time of ovulation because of the large variation found in the decrease of progesterone relative to ovulation. Although the prediction of ovation time using behavioural oestrus signs was quite accurate, it seems not suitable for practice because of the high labour requirements. The increase in the number of steps measured by pedometers seems useful to predict time of ovulation accurately and could be easily implemented in practice. Effects of the interval between insemination and ovulation on success of fertilization and embryonic characteristics were also studied. It was shown that the insemination-ovulation interval in which high fertilization rates were observed was quite long (insemination from 36 to 12h before ovulation), while the interval in which the majority of fertilized ovum developed into a good quality embryo was considerably shorter (insemination from 24 to 12h before ovulation); the interval between insemination and ovulation did not affect the sex ratio of the embryos.In conclusion, the best chance to increase calving rates seems to be to use the insemination strategy, in which cows are inseminated between 5 to 17h after the first increase in the number of steps

Right posterior parietal cortex is involved in disengaging from threat:a 1 Hz rTMS study

Contains fulltext : 178666.pdf (publisher's version ) (Open Access)The right posterior parietal cortex (PPC) is implicated in spatial attention, but its specific role in emotional spatial attention remains unclear. In the present study, we combined inhibitory transcranial magnetic stimulation (TMS) with a fear conditioning paradigm to test the role of the right PPC in attentional control of task-irrelevant threatening distractors. In a sham-controlled within-subject design, 1 Hz repetitive TMS was applied to the left and right PPC after which participants performed a visual search task with a distractor that was either associated with a loud noise burst (threat) or not (non-threat). Results demonstrated attentional capture across all conditions as evidenced by the typical reaction time costs of the distractor. However, only after inhibitory rTMS to the right PPC reaction time cost in the threatening distractor condition was increased relative to the non-threatening distractor condition, suggesting that attention lingered longer on the threatening distractor. We propose that the right PPC is involved in disengagement of attention from emotionally salient stimuli in order to re-orient attention to task relevant stimuli and may have implications for anxiety disorders associated with difficulties to disengage from threatening stimuli.9 p

Insemination strategy based on ovulation prediction in dairy cattle

Calving rates after first insemination are often less than 50% in practice. Part of this low percentage might be explained by wrongly timed inseminations. Our hypothesis is that it is better to time insemination according to ovulation instead of according to behavioral estrus, but up to now it has not been possible to predict the time of ovulation in practice. So, to better time inseminations in practice, there is a need for predictors of ovulation time. Therefore, the relationship between various estrus characteristics and time of ovulation was studied to investigate whether these characteristics could predict time of ovulation. First standing heat was displayed 26.4±5.2h before ovulation. The increase in number of steps during estrus predicted the time of ovulation (29.3±3.9h) best. The next question was: What is the best time for insemination relative to ovulation? When this time is known, an insemination strategy can be formulated. It was found that inseminations performed 24 to 12h before ovulation resulted in the highest number of good quality embryos at Day 7. This means that the optimal strategy is to inseminate 5 to 17h after the first increase in the number of steps. This strategy will result in optimal timed inseminations relative to time of ovulation

Time ambiguity during intertemporal decision-making is aversive, impacting choice and neural value coding

Contains fulltext : 196720.pdf (publisher's version ) (Open Access)We are often presented with choices that differ in their more immediate versus future consequences. Interestingly, in everyday-life, ambiguity about the exact timing of such consequences frequently occurs, yet it remains unknown whether and how time-ambiguity influences decisions and their underlying neural correlates. We developed a novel intertemporal fMRI choice task in which participants make choices between sooner-smaller (SS) versus later-larger (LL) monetary rewards with systematically varying levels of time-ambiguity. Across trials, delay information of the SS, the LL, or both rewards was either exact (e.g., in 5 weeks), of low ambiguity (4 week range: e.g., in 3-7 weeks), or of high ambiguity (8 week range: e.g., in 1-9 weeks). Choice behavior showed that the majority of participants preferred options with exact delays over those with ambiguous delays, indicating time-ambiguity aversion. Consistent with these results, the ventromedial prefrontal cortex showed decreased activation during ambiguous versus exact trials. In contrast, intraparietal sulcus activation increased during ambiguous versus exact trials. Furthermore, exploratory analyses suggest that more time-ambiguity averse participants show more insula and dorsolateral prefrontal cortex activation during subjective value (SV)-coding of ambiguous versus exact trials. Lastly, the best-fitting computational choice models indicate that ambiguity impacts the SV of options via time perception or via an additive ambiguity-related penalty term. Together, these results provide the first behavioral and neural signatures of time-ambiguity, pointing towards a unique profile that is distinct from impatience. Since time-ambiguity is ubiquitous in real-life, it likely contributes to shortsighted decisions above and beyond delay-discounting.9 p