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991.
992.
993.
Following stroke, aberrant three dimensional multijoint gait impairments emerge that present in kinematic asymmetries such as circumduction. A precise pattern of cross-planar coordination may underlie abnormal hemiparetic gait as several studies have underscored distinctive neural couplings between medio-lateral control and sagittal plane progression during walking. Here we investigate potential neuromechanical constraints governing abnormal multijoint coordination post-stroke. 15 chronic monohemispheric stroke patients and 10 healthy subjects were recruited. Coupled torque production patterns were assessed using a volitional isometric torque generation task where subjects matched torque targets for a primary joint in 4 directions while receiving visual feedback of the magnitude and direction of the torque. Secondary torques at other lower limb joints were recorded without subject feedback. We find that common features of cross-planar connectivity in stroke subjects include statistically significant frontal to sagittal plane kinetic coupling that overlay a common sagittal plane coupling in healthy subjects. Such coupling is independent of proximal or distal joint control and limb biomechanics. Principal component analysis of the stroke aggregate kinetic signature reveals unique abnormal frontal plane coupling features that explain a larger percentage of the total torque coupling variance. This study supports the idea that coupled cross-planar kinetic outflow between the lower limb joints uniquely emerges during pathological control of frontal plane degrees of freedom resulting in a generalized extension of the limb. It remains to be seen if a pattern of lower limb motor outflow that is centrally mediated contributes to abnormal hemiparetic gait. 相似文献
994.
Juncai Ma Zizhen Liang Jierui Zhao Pengfei Wang Wenlong Ma Keith K. Mai Juan A. Fernandez Andrade Yonglun Zeng Nenad Grujic Liwen Jiang Yasin Dagdas Byung-Ho Kang 《Current biology : CB》2021,31(9):1931-1944.e4
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995.
Summary The glycerol-3-phosphate dehydrogenase (GPDH, E. C. 1.1.1.8) gene ofDrosophila melanogaster contains a tandem duplication of a 4.5-kb-long DNA fragment. Survey of theGpdh gene region by the Southern blot analysis revealed the following features of this gene duplication: (1) The duplication was not observed in chromosome lines that carryIn(2L)t, a cosmopolitan chromosomal inversion in this species. The duplication and the inversion are in linkage disequilibrium. (2) The duplication is polymorphic in the Japan and US natural populations examined. Its frequency is 0.26 on an average inIn(2L)t-free chromosomes. (3) Triplication is absent or has not become frequent in the populations surveyed. Possible evolutionary factors of this duplication polymorphism are discussed. 相似文献
996.
We have examined the time course of the neuronal death and regeneration of rat axotomized hypoglossal nerve with various conditions of the nerve resection, and established a useful system to measure neurotrophic activities of bioactive substances. In this system, neuronal death can be evaluated by counting surviving neurons in the nucleus of hypoglossal neuron at the brain stem, and the degree of the regeneration can be measured by counting horseradish peroxidase-positive cells at the same region after injection of horseradish peroxidase into tongue. Using this system, the effects of brain gangliosides on rat hypoglossal nerve regeneration following 5 mm transection were examined. The addition of a ganglioside mixture from bovine brain as well as the autograft strongly prevented the death of neurons and promoted the regeneration of the lesioned nerve at 10 weeks after the operation. Further analyses on the dose effects and injection sites of gangliosides were performed. Although the mechanisms of the neurotrophic effects of the gangliosides are unknown, the therapeutic application of gangliosides for neuronal degeneration is a promising approach. 相似文献
997.
A black limestone collected from near Kantan, Trang Province, southern Thailand, contains two species of sphinctozoan sponge
which have been namedAmblysiphonella parva n. sp. andPlatythalamiella minima n. sp. The former is a cylindrical chambered sponge with an axial spongocoel and ring chambers.P. minima is an asiphonate and tabular sponge characterized by small chambers arranged in one or two layers above and beside each other.
Both are the smallest known species in their respective genera. Hypercalcified sponges have not previously been reported from
the Triassic of Thailand.
相似文献
998.
Arihide Kamaguchi Hisae Baba Masaaki Hoshi Koshiro Inomata 《Microbiology and immunology》1994,38(6):457-460
Coaggregation occurred between Porphyromonas gingivalis and mutans streptococci. The coaggregation was completely inhibited by l -arginine, Nα-p-tosyl-l -lysine chloromethyl ketone (TLCK), and a trypsin inhibitor, and weakly inhibited by l -lysine, N-ethylmaleimide, lysozyme, and human whole saliva. The results of heat and proteinase K treatment suggested that a heat-labile proteinaceous substance of P. gingivalis and a heat-stable substance of mutans streptococci may play a role in the coaggregation. Mutans streptococci also aggregated in the presence of the heat-labile factor in the supernatant of P. gingivalis. The aggregation was also inhibited by l -arginine, TLCK, and a trypsin inhibitor. 相似文献
999.
Yokota Takao; Baba Jun; Konomi Koji; Shimazaki Yukio; Takahashi Nobutaka; Furuya Masaki 《Plant & cell physiology》1982,23(2):265-271
Phytochrome killer, a substance which instantaneously causesin vitro spectral denaturation of phytochrome, was isolatedin the pure state from the methanol extract of etiolated peashoots by Sephadex G-25, charcoal and silica gel chromatographies.Chemical and spectrometric (nuclear magnetic resonance, massand infra-red) analyses disclosed that this substance was identicalwith soyasaponin I, a triterpenoid saponin. Most of the phytochromekiller activity in the methanol extract was ascribable to soyasaponinI. The content of this saponin was 61 µg/g fr wt in theetiolated epicotyl tissue and 27 µg/g fr wt in the greenepicotyl tissue. (Received August 15, 1981; Accepted December 16, 1981) 相似文献
1000.
Nobuo Sugiura Yuichi Baba Yoshirou Kawaguchi Toru Iwatani Kiyoshi Suzuki Takahiro Kusakabe Kiwamu Yamagishi Koji Kimata Yoshimitsu Kakuta Hideto Watanabe 《The Journal of biological chemistry》2010,285(3):1597-1606
Heparan sulfate is a ubiquitous glycosaminoglycan in the extracellular matrix of most animals. It interacts with various molecules and exhibits important biological functions. K5 antigen produced by Escherichia coli strain K5 is a linear polysaccharide N-acetylheparosan consisting of GlcUA β1–4 and GlcNAc α1–4 repeating disaccharide, which forms the backbone of heparan sulfate. Region 2, located in the center of the K5-specific gene cluster, encodes four proteins, KfiA, KfiB, KfiC, and KfiD, for the biosynthesis of the K5 polysaccharide. Here, we expressed and purified the recombinant KfiA and KfiC proteins and then characterized these enzymes. Whereas the recombinant KfiC alone exhibited no GlcUA transferase activity, it did exhibit GlcUA transferase and polymerization activities in the presence of KfiA. In contrast, KfiA had GlcNAc transferase activity itself, which was unaffected by the presence of KfiC. The GlcNAc and GlcUA transferase activities were analyzed with various truncated and point mutants of KfiA and KfiC. The point mutants replacing aspartic acid of a DXD motif and lysine and glutamic acid of an ionic amino acid cluster, and the truncated mutants deleting the C-terminal and N-terminal sites, revealed the essential regions for GlcNAc and GlcUA transferase activity of KfiC and KfiA, respectively. The interaction of KfiC with KfiA is necessary for the GlcUA transferase activity of KfiC but not for the enzyme activity of KfiA. Together, these results indicate that the complex of KfiA and KfiC has polymerase activity to synthesize N-acetylheparosan, providing a useful tool toward bioengineering of defined heparan sulfate chains. 相似文献