266 research outputs found
Impact of Dreissena fouling on the physiological condition of native and invasive bivalves : interspecific and temporal variations
The impact of Dreissena fouling on unionids
has hardly been studied in Europe, despite the fact
that in some ecosystems (e.g. Lake Balaton, Hungary)
infestations of several hundreds to a thousand individuals
per unionid have been observed. At present,
the zebra mussel Dreissena polymorpha is a dominant
species in Lake Balaton and in the last decade three
other invasive bivalves were introduced, potentially
increasing the pressure on native unionid survival. We
examined whether the fouling of dreissenids (zebra
and quagga (D. rostriformis bugensis) mussels) has a
negative impact on native (Anodonta anatina, Unio
pictorum and U. tumidus) and invasive (Corbicula
fluminea and Sinanodonta woodiana) bivalves and
whether there are any interspecific and temporal
variations in fouling intensity and physiological
condition measured by standard condition index and
glycogen content. A significant negative impact was detected on native unionids only in July and September
(no impact was detected in May), when the fouling
rate was high. For invasive species, a significant
negative impact was detected on S. woodiana with a
high level of dressenid infestation; whereas no significant
impact was detected on C. fluminea. Overall, this
study confirms that Dreissena may threaten unionid
species including the invasive S. woodiana, although
high interspecific and temporal variations were
observed. This situation should be taken into account
in future ecological and conservational assessments
because species respond differently to Dreissena
fouling and effects seem to be more pronounced in
late summer/early autumn. In addition, this study
provides the first evidence that the invasive C.
fluminea appear to be less vulnerable to dressenid
fouling.The study was supported by the Hungarian Scientific Fund (KTIA-OTKA) under the contract No. CNK80140
Utilization of IκB–EGFP Chimeric Gene as an Indicator to Identify Microbial Metabolites with NF-κB Inhibitor Activity
NF-κB regulates several important expressions, such as cytokine release, anti-apoptosis, adhesion molecule expression, and cell cycle processing. Several NF-κB inhibitors have been discovered as an anti-tumor or anti-inflammatory drug. The activity of NF-κB transcription factor is negatively regulated by IκB binding. In this study, IκB assay system was established and IκB–EGFP fusion protein was used as an indicator to monitor the effects of substances on the IκB degradation. The results indicated that the chosen hydroquinone could inhibit the IκB degradation and cause the cell de-attachment from the bottom of culture plate. In addition, this system could also monitor the IκB degradation of microbial metabolite of natural mixtures of propolis. Thus, the IκB assay system may be a good system for drug discovery related to microbial metabolite
Infectious disease among enslaved African Americans at Eaton's Estate, Warren County, North Carolina, ca. 1830-1850
Surface Feature-Guided Mapping of Cerebral Metabolic Changes in Cognitively Normal and Mildly Impaired Elderly
Purpose: The aim of this study was to investigate the longitudinal positron emission tomography (PET) metabolic changes in the elderly. Procedures: Nineteen nondemented subjects (mean Mini-Mental Status Examination 29.4±0.7 SD) underwent two detailed neuropsychological evaluations and resting 2-deoxy-2-[F-18]fluoro-D-glucose (FDG)-PET scan (interval 21.7±3.7 months), baseline structural 3T magnetic resonance (MR) imaging, and apolipoprotein E4 genotyping. Cortical PET metabolic changes were analyzed in 3-D using the cortical pattern matching technique. Results: Baseline vs. follow-up whole-group comparison revealed significant metabolic decline bilaterally in the posterior temporal, parietal, and occipital lobes and the left lateral frontal cortex. The declining group demonstrated 10–15 % decline in bilateral posterior cingulate/precuneus, posterior temporal, parietal, and occipital cortices. The cognitively stable group showed 2.5–5% similarly distributed decline. ApoE4-positive individuals underwent 5–15 % metabolic decline in the posterior association cortices. Conclusions: Using 3-D surface-based MR-guided FDG-PET mapping, significant metaboli
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Intolerance of uncertainty predicts fear extinction in amygdala-ventromedial prefrontal cortical circuitry
Background: Coordination of activity between the amygdala and ventromedial prefrontal cortex (vmPFC) is important for fear-extinction learning. Aberrant recruitment of this circuitry is associated with anxiety disorders. Here, we sought to determine if individual differences in future threat uncertainty sensitivity, a potential risk factor for anxiety disorders, underly compromised recruitment of fear extinction circuitry.
Twenty-two healthy subjects completed a cued fear conditioning task with acquisition and extinction phases. During the task, pupil dilation, skin conductance response, and functional magnetic resonance imaging were acquired. We assessed the temporality of fear extinction learning by splitting the extinction phase into early and late extinction. Threat uncertainty sensitivity was measured using self-reported intolerance of uncertainty (IU).
Results: During early extinction learning, we found low IU scores to be associated with larger skin conductance responses and right amygdala activity to learned threat vs. safety cues, whereas high IU scores were associated with no skin conductance discrimination and greater activity within the right amygdala to previously learned safety cues. In late extinction learning, low IU scores were associated with successful inhibition of previously learned threat, reflected in comparable skin conductance response and right amgydala activity to learned threat vs. safety cues, whilst high IU scores were associated with continued fear expression to learned threat, indexed by larger skin conductance and amygdala activity to threat vs. safety cues. In addition, high IU scores were associated with greater vmPFC activity to threat vs. safety cues in late extinction. Similar patterns of IU and extinction learning were found for pupil dilation. The results were specific for IU and did not generalize to self-reported trait anxiety.
Conclusions: Overall, the neural and psychophysiological patterns observed here suggest high IU individuals to disproportionately generalize threat during times of uncertainty, which subsequently compromises fear extinction learning. More broadly, these findings highlight the potential of intolerance of uncertainty-based mechanisms to help understand pathological fear in anxiety disorders and inform potential treatment targets
Assessing young people's political engagement: a critical and systematic literature review of the instruments used to measure political engagement
Over the past few decades, there has been an increasing interest in understanding youth political engagement. However, it has been argued that the instruments used to assess the concept often lack adequate validation, and this is important as this practice may result in biased statistical conclusions. Consequently, the main aim of the present study was to systematically review, summarize, and critique the extant research evidence on the development of psychometric instruments that assess young people’s political engagement. Following a systematic review of the literature, seven instruments were identified that were both valid and reliable, but none explicitly assessed young people’s political engagement. Instead, they considered broad concepts and/or dimensions related to political engagement. Emphasising the lack of statistically robust standardised measurement tools that empirically assess young people’s political engagement, the available evidence confirms the pressing need to adopt a robust psychometric approach to assess political engagement in youth
Integration of face and voice during emotion perception : is there anything gained for the perceptual system beyond stimulus modality redundancy?
Gene targeting in adult rhesus macaque fibroblasts
<p>Abstract</p> <p>Background</p> <p>Gene targeting in nonhuman primates has the potential to produce critical animal models for translational studies related to human diseases. Successful gene targeting in fibroblasts followed by somatic cell nuclear transfer (SCNT) has been achieved in several species of large mammals but not yet in primates. Our goal was to establish the protocols necessary to achieve gene targeting in primary culture of adult rhesus macaque fibroblasts as a first step in creating nonhuman primate models of genetic disease using nuclear transfer technology.</p> <p>Results</p> <p>A primary culture of adult male fibroblasts was transfected with hTERT to overcome senescence and allow long term <it>in vitro </it>manipulations. Successful gene targeting of the HPRT locus in rhesus macaques was achieved by electroporating S-phase synchronized cells with a construct containing a SV40 enhancer.</p> <p>Conclusion</p> <p>The cell lines reported here could be used for the production of null mutant rhesus macaque models of human genetic disease using SCNT technology. In addition, given the close evolutionary relationship and biological similarity between rhesus macaques and humans, the protocols described here may prove useful in the genetic engineering of human somatic cells.</p
Transgene Expression Is Associated with Copy Number and Cytomegalovirus Promoter Methylation in Transgenic Pigs
Transgenic animals have been used for years to study gene function, produce important proteins, and generate models for the study of human diseases. However, inheritance and expression instability of the transgene in transgenic animals is a major limitation. Copy number and promoter methylation are known to regulate gene expression, but no report has systematically examined their effect on transgene expression. In the study, we generated two transgenic pigs by somatic cell nuclear transfer (SCNT) that express green fluorescent protein (GFP) driven by cytomegalovirus (CMV). Absolute quantitative real-time PCR and bisulfite sequencing were performed to determine transgene copy number and promoter methylation level. The correlation of transgene expression with copy number and promoter methylation was analyzed in individual development, fibroblast cells, various tissues, and offspring of the transgenic pigs. Our results demonstrate that transgene expression is associated with copy number and CMV promoter methylation in transgenic pigs
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