9 research outputs found
Trichinella spiralis, potential model nematode for epigenetics and its implication in metazoan parasitism
No full textThe recent discovery of DNA methylation in the nematode T. spiralis may raise the possibility of using it as a potential model organism for epigenetic studies instead of C. elegans, which is deficient in this important epigenetic modification. In contrast to the free-living nematode C. elegans, T. spiralis is a parasitic worm that possesses a complicated life cycle and undergoes a complex developmental regulation of genes. We emphasise that the differential methylomes in the different life-history stages of T. spiralis can provide insight on how DNA methylation is triggered and regulated. In particular, we have demonstrated that DNA methylation is involved in the regulation of its parasitism-related genes. Further computational analyses indicated that the regulatory machinery for DNA methylation can also be found in the T. spiralis genome. By a logical extension of this point, we speculate that comprehensively addressing the epigenetic machinery of T. spiralis may help to understand epigenetics in invertebrates. Furthermore, considering the implication of epigenetics in metazoan parasitism, using T. spiralis as an epigenetic model organism may further contribute to drug development against metazoan parasites
Identification of microRNAs and their targets associated with fruit-bagging and subsequent sunlight re-exposure in the ‘Granny Smith’ apple exocarp using high-throughput sequencing
No full textBagged fruits of green apple cultivar ‘Granny Smith’ have been found to turn cardinal red after debagging during fruit-ripening in the Loess Plateau region of China. To understand such phenomenon at post-transcriptional level, we have investigated the roles of microRNAs (miRNAs) in response to debagging. Three small RNA libraries were primarily constructed from peels of ‘Granny Smith’ apples subjected to bagging followed by sunlight re-exposure treatments (0h, 6h, 1d) (debagging), and from peels of apples without any bagging treatments (0h, 6h, 1d). 201 known miRNAs belonging to 43 miRNA families and 220 novel miRNAs were identified via high-throughput sequencing. Some miRNAs were found to be differentially expressed after debagging, which indicated that miRNAs affected anthocyanin accumulation through their target genes in mature apple. To further explore the effect of debagging on miRNAs regulating the expression of anthocyanin regulatory genes, four miRNAs and their target genes regulating anthocyanin accumulation, miR156, miR828, miR858 and miR5072, were compared between green cultivar ‘Granny Smith’ and red cultivar ‘Starkrimson’. Results showed that mdm-miR828 and mdm-miR858 regulated anthocyanin contents in both apple cultivars, while mdm-miR156 only affected anthocyanin accumulation in ‘Granny Smith’, and miR5072 affected anthocyanin accumulation in ‘Starkrimson’. Additional analysis of gene ontology for the differentially expressed miRNAs after debagging treatments and their predicted target genes showed that they were involved in photo-protective response after debagging from 0h to 1d; they might play important roles in fruit development and adaptation to high light stress
Dendritic morphology, synaptic transmission, and activity of mature granule cells born following pilocarpine-induced status epilepticus in the rat
No full textTo understand the potential role of enhanced hippocampal neurogenesis after pilocarpine-induced status epilepticus (SE) in the development of epilepsy, we quantitatively analyzed the geometry of apical dendrites, synaptic transmission, and activation levels of normotopically distributed mature newborn granule cells in the rat.SE in male Sprague-Dawley rats lasting for more than 2 hours was induced by an intraperitoneal injection of pilocarpine. The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born five days after SE were studied at least 10 weeks after CAG-GFP retroviral vector-mediated labeling.Mature granule cells born after SE had dendritic complexity similar to that of granule cells born naturally, but with denser mushroom-like spines in dendritic segments located in the outer molecular layer. Miniature inhibitory post-synaptic currents (mIPSCs) were similar between the controls and rats subjected to SE; however, smaller miniature excitatory post-synaptic current (mEPSC) amplitude with a trend toward less frequent was found in mature granule cells born after SE. After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or after being activated by transient seizure activity than vicinal GFP-unlabeled granule cells.Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells
Odors bias time perception in visual and auditory modalities
No full textPrevious studies have shown that emotional states alter our perception of time. However, attention, which is modulated by a number of factors, such as emotional events, also influences time perception. To exclude potential attentional effects associated with emotional events, various types of odors (inducing different levels of emotional arousal) were used to explore whether olfactory events modulated time perception differently in visual and auditory modalities. Participants were shown either a visual dot or heard a continuous tone for 1000 ms or 4000 ms while they were exposed to odors of jasmine, lavender, or garlic. Participants then reproduced the temporal durations of the preceding visual or auditory stimuli by pressing the spacebar twice. Their reproduced durations were compared to those in the control condition (without odor). The results showed that participants produced significantly longer time intervals in the lavender condition than in the jasmine or garlic conditions. The overall influence of odor on time perception was equivalent for both visual and auditory modalities. The analysis of the interaction effect showed that participants produced longer durations than the actual duration in the short interval condition, but they produced shorter durations in the long interval condition. The effect sizes were larger for the auditory modality than those for the visual modality. Moreover, by comparing performance across the initial and the final blocks of the experiment, we found odor adaptation effects were mainly manifested as longer reproductions for the short time interval later in the adaptation phase, and there was a larger effect size in the auditory modality. In summary, the present results indicate that odors imposed differential impacts on reproduced time durations, and they were constrained by different sensory modalities, valence of the emotional events, and target durations. Biases in time perception could be accounted for by a framework of attentional deployment between the inducers (odors) and emotionally neutral stimuli (visual dots and sound beeps)
Inflammatory Stress Potentiates Emodin-Induced Liver Injury in Rats
No full textHerbal medicines containing emodin, widely used for the treatment of hepatitis in clinic, have been reported with hepatotoxicity in individuals. A modest inflammatory stress potentiating liver injury has been linked to the idiosyncratic drug-induced liver injury (IDILI). In this study, we investigated the hypothesis that lipopolysaccharide (LPS) interacts with emodin could synergize to cause liver injury in rats. Emodin (ranging from 20, 40 to 80 mg/kg), which is in the range of liver protection, was administered to rats, before LPS (2.8 mg/kg) or saline vehicle treatment. The biochemical tests showed that non-toxic dosage of LPS coupled with emodin caused significant increases of plasma ALT and AST activities as compared to emodin alone treated groups (P<0.05). In addition, with LPS or emodin alone could not induce any changes in ALT and AST activity, as compared with the control group (0.5% CMC-Na treatment). Meanwhile, the plasma proinflammatory cytokines, TNF-α, IL-1β, and IL-6 increased significantly in the emodin/LPS groups compared to either emodin groups or the LPS (P<0.05). Histological analysis showed that liver damage was only found in emodin/LPS cotreatmented rat livers samples. These results indicate that non-toxic dosage of LPS potentiates the hepatotoxicity of emodin. This discovery raises the possibility that emodin and herbal medicines containing it may induce liver injury in the inflammatory stress even in their therapeutic dosages
Multiscale analysis of biological data by scale-dependent Lyapunov exponent
No full textPhysiological signals often are highly nonstationary and multiscaled--- depending upon the scale at which they are examined, they mayexhibit different behaviors, such asnonlinearity, sensitive dependence on small disturbances, longmemory, and extreme variations. Such data have been accumulatingrapidly in all areas ofhealth sciences.It is very desirable to characterize the differentbehaviors of such signals on a wide range of scales simultaneously.The scale-dependent Lyapunov exponent (SDLE) is capable of such afundamental task. In particular, SDLE can readilycharacterize all known types of data, includingdeterministic chaos, noisy chaos,random processes, stochastic limit cycles, among others. It can alsoreadily deal with many types of nonstationarity anddetect intermittent chaos.To illustrate its effectiveness in analyzing physiological data,we consider detection of epileptic seizures from EEG and certaincardiac disease from heart rate variability (HRV) data.In particular, we show that commonlyused complexity measures for physiological data, including thosefrom information theory, chaos theory, and random fractal theory, can all be related to thevalues of the SDLE at specific scales, and therefore,SDLE can act as the basis for a unified theory ofmultiscale analysis of complex data
Stochastic Learning in Oxide Binary Synaptic Device for Neuromorphic Computing
No full textHardware implementation of neuromorphic computing is attractive as a computing paradigm beyond the conventional digital computing. In this work, we show that the SET (off-to-on) transition of metal oxide resistance switching memory becomes probabilistic under a weak programming condition. The switching variability of the binary synaptic device implements a stochastic learning rule. Such stochastic SET transition was statistically measured and modeled for a simulation of a winner-take-all network for competitive learning. The simulation illustrates that with such stochastic learning, the orientation classification function of input patterns can be effectively realized. The system performance metrics were compared between the conventional approach using the analog synapse and the approach in this work that employs the binary synapse utilizing the stochastic learning. The feasibility of using binary synapse in the neurormorphic computing may relax the constraints to engineer continuous multilevel intermediate states and widens the material choice for the synaptic device design
Aging interferes central control mechanism for eccentric muscle contraction
No full textPrevious studies report greater activation in the cortical motor network in controlling eccentric contraction (EC) than concentric contraction (CC) despite lower muscle activation level associated with EC vs. CC in healthy, young individuals. It is unknown, however, whether elderly people exhibiting increased difficulties in performing EC than CC possess this unique cortical control mechanism for EC movements. To address this question, we examined functional MRI (fMRI) data acquired during EC and CC of the first dorsal interosseous (FDI) muscle in 11 young (20-32 years) and 9 old (67-73 years) individuals. During the fMRI experiment, all subjects performed 20 CC and 20 EC of the right FDI with the same angular distance and velocity. The major findings from the behavioral and fMRI data analysis were that (1) movement stability was poorer in EC than CC in the old but not the young group; (2) similar to previous electrophysiological and fMRI reports, the EC resulted in significantly stronger activation in the motor control network consisting of primary, secondary and association motor cortices than CC in the young and old groups; (3) the biased stronger activation towards EC was significantly greater in the old than the young group especially in the secondary and association cortices such as supplementary and premotor motor areas and anterior cingulate cortex; and (4) in the primary motor and sensory cortices, the biased activation towards EC was significantly greater in the young than the old group. Greater activation in higher-order cortical fields for controlling EC movement by elderly adults may reflect activities in these regions to compensate for aging-related impairments in the ability to control complex EC movements. Our finding is useful for potentially guiding the development of targeted therapies to counteract age-related movement deficits and to prevent injury
