Sequential neural processes in abacus mental addition: an EEG and FMRI case study

Abacus experts are able to mentally calculate multi-digit numbers rapidly. Some behavioral and neuroimaging studies have suggested a visuospatial and visuomotor strategy during abacus mental calculation. However, no study up to now has attempted to dissociate temporally the visuospatial neural process from the visuomotor neural process during abacus mental calculation. In the present study, an abacus expert performed the mental addition tasks (8-digit and 4-digit addends presented in visual or auditory modes) swiftly and accurately. The 100% correct rates in this expert's task performance were significantly higher than those of ordinary subjects performing 1-digit and 2-digit addition tasks. ERPs, EEG source localizations, and fMRI results taken together suggested visuospatial and visuomotor processes were sequentially arranged during the abacus mental addition with visual addends and could be dissociated from each other temporally. The visuospatial transformation of the numbers, in which the superior parietal lobule was most likely involved, might occur first (around 380 ms) after the onset of the stimuli. The visuomotor processing, in which the superior/middle frontal gyri were most likely involved, might occur later (around 440 ms). Meanwhile, fMRI results suggested that neural networks involved in the abacus mental addition with auditory stimuli were similar to those in the visual abacus mental addition. The most prominently activated brain areas in both conditions included the bilateral superior parietal lobules (BA 7) and bilateral middle frontal gyri (BA 6). These results suggest a supra-modal brain network in abacus mental addition, which may develop from normal mental calculation networks.     

An effective sample preparation approach for screening the anticancer compound piceatannol using HPLC coupled with UV and fluorescence detection

Piceatannol, compared with the renowned resveratrol, is a better anticancer agent and a superior agent with other biological activities. However, as there are only few plants reported to contain minute quantity of piceatannol, the scarcity of sources greatly impedes the piceatannol-related researches. To explore new sources of piceatannol, we established a sample preparation approach for screening the piceatannol in plants using HPLC-UV-fluorescence detection. When the HPLC is coupled with UV and fluorescence detectors, the decrease of signals in interferences and increase of signal in piceatannol in the fluorescence chromatogram mark clearly the position of the piceatannol peak; ultimately, it allows identification without standards. In this study, we systematically evaluated the factors affecting the extraction efficiency of piceatannol in sample preparation. Of the sample preparation strategies studied, direct solvent extraction and liquid nitrogen treatment followed by solvent extraction gave satisfactory recoveries for both piceatannol and resveratrol. These approaches avoided time-consuming lyophilization procedure. In addition, all procedures must be done in the dark to avoid negative impact of irradiation from fluorescence light on the recoveries of piceatannol and resveratrol. With the present method, we re-examined the plants previously claimed to contain only resveratrol for their piceatannol contents. The species examined included Polygonum cuspidatum, Arachis hypogaea, Vitis thunbergii, and Ampelopsis brevipedunculaata. The results showed, for the first time, all these plants contain piceatannol. The finding implies that the resveratrol-containing plants may also contain piceatannol. The results demonstrate the feasibility of these sample preparation approaches and may further the understanding for the distribution of piceatannol in plants.     

A new synnematous species of Penicillium from soil in Taiwan

A synnematous species of Penicillium, P. calidicanium, is described and illustrated. The fungus was isolated from soil in Taiwan. Penicillium calidicanium can be placed in subgenus Biverticillium because of its symmetrical, biverticillate penicilli, ampulliform to acerose phialides, and ability to produce abundant synnemata in Czapek yeast extract agar, malt extract agar, and Czapek's solution agar. It is close to P. duclauxii and P. vulpinum, but differs in colony morphology, growth rate, morphology of the synnemata, and ornamentation of the conidial wall.     

Latent microsporidial infection in immunocompetent individuals - a longitudinal study

Background

Microsporidia (Fungi) have been repeatedly identified as the cause of opportunistic infections predominantly in immunodeficient individuals such as AIDS patients. However, the global epidemiology of human microsporidiosis is poorly understood and the ability of microsporidia to survive and multiply in immunocompetent hosts remains unsolved.

Aims

To determine the presence of latent microsporidia infections in apparently healthy humans in the Czech Republic, the authors tested sera, urine and stool originating from fifteen persons within a three month period examined on a weekly basis.

Methods

Sera, stool and urine samples originating from fifteen HIV-negative people at risk with occupational exposure to animals, aged 22–56 years, living in the Czech Republic were tested by indirect immunofluorescence assay (IFA) for the presence of specific anti-microsporidial antibodies, standard Calcofluor M2R staining for the detection of microsporidian spores in all urine sediments and stool smears and molecular methods for the microsporidial species determination.

Results

Specific anti-microsporidial antibodies were detected in fourteen individuals, asymptomatic Encephalitozoon spp. infection was found in thirteen and E. bieneusi infection was detected in seven of those examined. While E. hellem 1A and E. cuniculi II were the major causative agents identified, seven different genotypes of E. bieneusi were recorded.

Conclusions

These findings clearly show that exposure to microsporidia is common and chronic microsporidiosis is not linked to any clinical manifestation in healthy population. Moreover, our results indicate much higher incidence of microsporidial infections among an apparently healthy population than previously reported. These results open the question about the potential risk of reactivation of latent microsporidiosis in cases of immunosupression causing life-threatening disease.     

Identification of CD133-positive radioresistant cells in atypical teratoid/rhabdoid tumor

Atypical teratoid/rhabdoid tumor (AT/RT) is an extremely malignant neoplasm in the central nervous system (CNS) which occurs in infancy and childhood. Recent studies suggested that CD133 could be considered a marker for brain cancer stem-like cells (CSCs). However, the role of CD133 in AT/RT has never been investigated. Herein we report the isolation of CD133-positive cells (CD133(+)), found to have the potential to differentiate into three germ layer tissues, from tissues of nine AT/RT patients. The migration/invasion/malignancy and radioresistant capabilities of CD133(+) were significantly augmented when compared to CD133(-). The clinical data showed that the amount of CD133(+) in AT/RTs correlated positively with the degree of resistance to radiation therapy. Using cDNA microarray analysis, the genotoxic-response profiles of CD133(+) and CD133(-) irradiated with 10 Gy ionizing radiation (IR) were analyzed 0.5, 2, 6, 12 and 24 h post-IR. We then validated these microarray data and showed increased phosphorylation after IR of p-ATM, p-RAD17, and p-CHX2 as well as increased expression of BCL-2 protein in CD133(+) compared to CD133(-). Furthermore, we found that CD133(+) can effectively resist IR with cisplatin- and/or TRAIL-induced apoptosis. Immunohistochemical analysis confirmed the up-regulated expression of p-ATM and BCL-2 proteins in IR-treated CD133(+) xenotransgrafts in SCID mice but not in IR-treated CD133(-). Importantly, the effect of IR in CD133(+) transplanted mice can be significantly improved by a combination of BCL-2 siRNA with debromohymenialdisine, an inhibitor of checkpoint kinases. In sum, this is the first report indicating that CD133(+) AT/RT cells demonstrate the characteristics of CSCs. The IR-resistant and anti-apoptotic properties in CD133(+) may reflect the clinical refractory malignancy of AT/RTs and thus the activated p-ATM pathway and BCL-2 expression in CD133(+) could be possible targets to improve future treatment of deadly diseases like AT/RT.     

Biodegradation of [C]Tri-p-Cresyl Phosphate in a Laboratory Activated-Sludge System

Biodegradation of [C]tri-p-cresyl phosphate was studied in a laboratory model sewage treatment system to develop information on the nature of its transformation products. In 24-h experiments, 70 to 80% of tri-p-cresyl phosphate added at the 1-mug/ml level was degraded. The remaining parent compound was associated with the sludge solids. The major metabolite extracted with ethyl ether from the aqueous phase was identified as p-hydroxybenzoic acid by gas chromatography-mass spectrometry. Two unstable ether-extractable metabolites were not identified. The half-life of [C]tri-p-cresyl phosphate was estimated to be 7.5 h.     

A Study of Glutathione <Emphasis Type="Italic">S</Emphasis>-transferase pi Expression in Central Nervous System of Subjects with Amyotrophic Lateral Sclerosis Using RNA Extraction from Formalin-Fixed,Paraffin-Embedded Material

The expression of glutathione S-transferase pi (GST pi), an enzyme responsible for inactivation of a large variety of toxic compounds was studied in spinal cord, motor and sensory brain cortex obtained from patients who died in the course of amyotrophic lateral sclerosis (ALS). The studies were performed on formalin-fixed, paraffin-embedded (FFPE) and freshly frozen tissues. The method of RNA isolation from FFPE was modified. A significant decrease of GST pi-mRNA expression was found in cervical spinal cord and motor brain cortex of ALS subjects comparing to analogue control tissues (P < 0.01), as well as in motor cortex of ALS subjects comparing to their sensory cortex (P < 0.05). In spinal cords the decrease in GST pi-mRNA expression was accompanied by a decrease of GST pi protein level. Results indicated lowered GST pi expression on both mRNA and protein levels in the regions of nervous system affected by ALS. The non-properly inactivated by GST toxic electrophiles and organic peroxides may thus contribute to motor neurons damage.     

Real-time imaging of lipid domains and distinct coexisting membrane protein clusters

A detailed understanding of biomembrane architecture is still a challenging task. Many in vitro studies have shown lipid domains but much less information is known about the lateral organization of membrane proteins because their hydrophobic nature limits the use of many experimental methods. We examined lipid domain formation in biomimetic Escherichia coli membranes composed of phosphatidylethanolamine and phosphatidylglycerol in the absence and presence of 1% and 5% (mol/mol) membrane multidrug resistance protein, EmrE. Monolayer isotherms demonstrated protein insertion into the lipid monolayer. Subsequently, Brewster angle microscopy was applied to image domains in lipid matrices and lipid-protein mixtures. The images showed a concentration dependent impact of the protein on lipid domain size and shape and more interestingly distinct coexisting protein clusters. Whereas lipid domains varied in size (14-47μm), protein clusters exhibited a narrow size distribution (2.6-4.8μm) suggesting a non-random process of cluster formation. A 3-D display clearly indicates that these proteins clusters protrude from the membrane plane. These data demonstrate distinct co-existing lipid domains and membrane protein clusters as the monofilm is being compressed and illustrate the significant mutual impact of lipid-protein interactions on lateral membrane architecture.