Biofeedback modification of frontal EMG in normal subjects

We carried out a controlled study on the voluntary control of the frontalis muscle by biofeedback procedures employing 20 normal subjects. Subjects were randomly divided into two groups of 10: (1) the biofeedback group and (2) the control group. Each of the two groups received five training sessions of about 40 minutes' duration each on different days. The results obtained are as follows: (1) In the biofeedback group, mean EMG levels decreased progressively and markedly from 2.16µVp-p min in the first session to 1.54µVp-p min in the last session. On the contrary, the control group did not show constant decreases in EMG levels over sessions. (2) The changes in the heart rate did not correlate with the changes in EMG activity. (3) The changes in the respiratory rate correlated with the changes in EMG activity.     

Kinetic analysis of the entire RNA amplification process by Qbeta replicase

The kinetics of the RNA replication reaction by Qbeta replicase were investigated. Qbeta replicase is an RNA-dependent RNA polymerase responsible for replicating the RNA genome of coliphage Qbeta and plays a key role in the life cycle of the Qbeta phage. Although the RNA replication reaction using this enzyme has long been studied, a kinetic model that can describe the entire RNA amplification process has yet to be determined. In this study, we propose a kinetic model that is able to account for the entire RNA amplification process. The key to our proposed kinetic model is the consideration of nonproductive binding (i.e. binding of an enzyme to the RNA where the enzyme cannot initiate the reaction). By considering nonproductive binding and the notable enzyme inactivation we observed, the previous observations that remained unresolved could also be explained. Moreover, based on the kinetic model and the experimental results, we determined rate and equilibrium constants using template RNAs of various lengths. The proposed model and the obtained constants provide important information both for understanding the basis of Qbeta phage amplification and the applications using Qbeta replicase.     

Evaluating the relationships between the postural adaptation of patients with profound cerebral palsy and the configuration of the Seating Buggy's seating support surface

We are currently investigating the physiological polymorphism of wheelchair users with profound cerebral palsy and the properties of the Seating Buggy (developed by S. Nishimura, 1998) to clarify important and general elements of wheelchairs for widespread use. Cerebral palsy is a diagnostic term used to describe a group of motor syndromes resulting from disorders in early brain development. Recently, it has been shown that the Seating Buggy produces functional head-neck alignments and active control of sitting balance for people with profound cerebral palsy. The Seating Buggy is a wheelchair for the profoundly disabled and features a wide adjustment range from heights of 120 cm to 175 cm. Its seating support surface is comprised of a sling-seat. To examine the relationships between the postural adaptation of patients with profound cerebral palsy and the configuration of the Seating Buggy's seating, we assessed the postural alignment of the Seating Buggy's user and then measured the configuration of its resulting seating support surface with a three dimensional scanning system. Twenty-one subjects were used for the purposes of this investigation in their everyday environment. Postural adaptation and wheelchair fitting in the Seating Buggy were assessed from the viewpoint of the Active Balanced Seating by a seating expert. The subjects fell into two categories, as follows: 11 for appropriate or nearly appropriate fitting, and 10 for ill-fitting. The depth of thoracic support and the forward distance of lumbar support for those who claimed that it was ill-fitting were significantly reduced compared with that of those who claimed that the Seating Buggy offered an appropriate or nearly appropriate fitting. It was suggested that the properly adjusted depth of thoracic support and distance of the lumbar support were related to the resulting satisfactory head-neck alignment and sitting balance of the patients with profound cerebral palsy.     

The lipid raft proteins flotillins/reggies interact with Galphaq and are involved in Gq-mediated p38 mitogen-activated protein kinase activation through tyrosine kinase

The heterotrimeric G protein alpha q subunit (Galphaq) mediates a variety of cell functions by activating the effector molecule phospholipase Cbeta. Galphaq activity is regulated by G protein betagamma subunits, G protein-coupled receptors, RGS proteins, and Ric-8. In this study, we identified the lipid raft resident proteins, flotillin-1/reggie-2 and flotillin-2/reggie-1, as Galphaq-binding proteins. The interactions of Galphaq and flotillins were independent of the nucleotide-binding state of Galphaq, and the N-terminal portion of flotillins was critical for the interaction. A short interfering RNA-mediated knockdown of flotillins, particularly flotillin-2, attenuated the UTP-induced activation of p38 mitogen-activated protein kinase (MAPK) but not that of ERK1/2. The activation of p38 MAPK was inhibited by the Src family tyrosine kinase inhibitor PP2 and the cholesterol-depleting agent methyl-beta-cyclodextrin, which is generally used for the disruption of lipid rafts. In contrast, the activation of ERK1/2 was not inhibited by these compounds. These lines of evidence suggested that a Gq-coupled receptor activates specifically p38 MAPK through lipid rafts and Src kinase activation, in which flotillins positively modulate the Gq signaling.     

Development of a reporter peptide that catalytically produces a fluorescent signal through α-complementation

In α-complementation, inactive N-terminal (α-domain) and C-terminal (ω-domain) fragments of β-galactosidase associate to reconstitute the active protein. To date, the effect of α-domain size on α-complementation activity has not been systematically investigated. In this study, we compared the complementation activities of α-domains of various sizes using an in vitro system. We found that the complementation activities are similar for α-domains comprising between 45 and 229 N-terminal residues but are significantly decreased for those containing less than 37 residues. However, these smaller α-domains (15 and 25 residues) exhibited sufficient α-complementation activity for application as reporters.     

Identification of peak bone mass QTL in a spontaneously osteoporotic mouse strain

The whole genome scan for quantitative trait loci (QTLs) specifying peak bone mass was performed with the F₂ intercrosses of SAMP6, an established murine model of senile osteoporosis, exhibiting a significantly lower peak bone mass, and SAMP2, exhibiting a higher peak bone mass. Cortical thickness index (CTI), a parameter of bone mass of femurs, was measured in 488 F₂ progeny at 4 months of age, when the animals attained peak bone mass by microphotodensitometry. Genetic markers were typed at 90 loci spanning all chromosomes except the Y. By interval mapping of 246 male F₂ mice, two loci were identified with significant linkage to peak bone mass, one on Chromosome (Chr) 11 and another on Chr 13, with a maximum lod score of 10.8 (22.2% of the total variance) and 5.8 (10.0%), respectively. Another locus on the X Chr was suggestive of a QTL associated oppositely with a low peak bone mass to the SAMP2 allele. This association was consistent with the distribution of peak bone mass in the F₁ and F₂. These findings should be useful to elucidate the genetics of osteoporosis. Received: 27 July 1998 / Accepted: 7 October 1998     

黄土丘陵区植被类型与土壤微生物区系及生物量的关系

以陕西延安黄土丘陵区5种不同植被类型(人工刺槐林、天然侧柏林、天然辽东栎林、灌丛和裸地)为研究对象,分析了土壤微生物生物量碳、氮含量、细菌和真菌的丰度变化规律及其与土壤基本化学性质的关系。结果表明:(1)4种植被类型的土壤质量较之裸地都有不同程度的改善,总体趋势:天然林地人工林地裸地;(2)土壤微生物生物量碳、氮的总体趋势:天然林地最高,人工林次之,裸地最低,且与土壤有机碳(SOC)、全氮(TN)和速效磷(AP)极显著正相关(P0.01);(3)裸地土壤的细菌丰度最低,人工刺槐林真菌含量显著低于天然辽东栎林。细菌丰度与土壤营养状况呈显著正相关(P0.05),而真菌与土壤营养无明显相关性,只与土壤pH负相关。说明在该研究区域,植被类型与土壤质量对微生物资源都具有不同程度的作用。     

A comparison of pressure–volume curves with and without rehydration pretreatment in eight woody species of the semiarid Loess Plateau

Pressure–volume (P–V) curves are frequently used to analyze water relation properties of woody plants in response to transpiration-induced tissue water loss. In this study, P–V analyses were conducted on eight woody species growing in the semiarid Loess Plateau region of China during a relatively dry summer season using both the recently recommended instantaneous measurement and the traditional method with rehydration pretreatment. Generally, P–V-derived parameters in this study reflected conditions in a dry growth environment. Species-specific differences were also found among P–V parameters, suggesting each species uses different mechanisms to respond to drought. Based on the results from instantaneous measurements, a descending sequence for drought tolerance ranked by water potentials at the turgor loss point (Ψ^tlp) was Rosa hugonis > Syringa oblata = Armeniaca sibirica > Caragana microphylla > Pyrus betulaefolia > Acer stenolobum > Quercus liaotungensis > Robinia pseudoacacia. The first five species also showed lower levels of osmotic potential at full turgor (Ψ _π ^sat ) and higher symplastic osmotic solute content per dry weight, suggesting they possess advantages in osmotic adjustment. Also, this study supports previous reports noting rehydration pretreatment resulted in shifts in P–V parameters. The magnitude of the shifts varied with species and water conditions. The effect of rehydration was stronger for species with higher drought tolerance or subjected to the influence of drought. Differences in the parameters among species were mitigated as a result of rehydration. Those with a lower Ψ^tlp or midday water potential were more deeply affected by rehydration. Application of instantaneous measurements was strongly recommended for proper analysis of P–V curves particularly in arid and semiarid areas.     

A design principle for a single-stranded RNA genome that replicates with less double-strand formation

Single-stranded RNA (ssRNA) is the simplest form of genetic molecule and constitutes the genome in some viruses and presumably in primitive life-forms. However, an innate and unsolved problem regarding the ssRNA genome is formation of inactive double-stranded RNA (dsRNA) during replication. Here, we addressed this problem by focusing on the secondary structure. We systematically designed RNAs with various structures and observed dsRNA formation during replication using an RNA replicase (Qβ replicase). From the results, we extracted a simple rule regarding ssRNA genome replication with less dsRNA formation (less GC number in loops) and then designed an artificial RNA that encodes a domain of the β-galactosidase gene based on this rule. We also obtained evidence that this rule governs the natural genomes of all bacterial and most fungal viruses presently known. This study revealed one of the structural design principles of an ssRNA genome that replicates continuously with less dsRNA formation.