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41.
Y Sumi M A Dent D E Owen P J Seeley R J Morris 《Development (Cambridge, England)》1992,116(3):625-637
Tissue and urokinase-type plasminogen activators are serine proteases with highly restricted specificity, their best characterised role being to release the broad specificity protease plasmin from inactive plasminogen. It has frequently been suggested that these, and similar proteases, are involved in axonal growth and tissue remodelling associated with neural development. To help define what this role might be, we have studied the expression of the plasminogen activators in developing rat nervous tissue. Urokinase-type plasminogen activator mRNA is strongly expressed by many classes of neurons in peripheral and central nervous system. We have analysed its appearance in spinal cord and sensory ganglia, and found the mRNA is detectable by in situ hybridisation very early in neuronal development (by embryonic day 12.5), at a stage compatible with it playing a role in axonal or dendritic growth. Tissue plasminogen activator mRNA, on the other hand, is expressed only by cells of the floor plate in the developing nervous system, from embryonic day 10.5 and thereafter. Immunohistochemical and enzymatic analysis showed that active tissue plasminogen activator is produced by, and retained within, the floor plate. A mechanism is suggested by which high levels of tissue plasminogen activator produced by the stationary cells of the floor plate could influence the direction of growth of commissural axons as they pass through this midline structure. 相似文献
42.
Mouse knockout of guanylyl cyclase C: Recognition memory deficits in the absence of activity changes
Elizabeth A. Mann Chiho Sugimoto Michael T. Williams Charles V. Vorhees 《Genes, Brain & Behavior》2019,18(5)
Guanylyl cyclase C (GC‐C) is found in brain regions where dopamine is expressed. We characterized a mouse in which GC‐C was knocked out (KO) that was reported to be a model of attention deficit hyperactivity disorder (ADHD). We re‐examined this model and controlled for litter effects, used 16 to 23 mice per genotype per sex and assessed an array of behavioral and neurochemical outcomes. GC‐C KO mice showed no phenotypic differences from wild‐type mice on most behavioral tests, or on striatal or hippocampal monoamines, and notably no evidence of an ADHD‐like phenotype. KO mice were impaired on novel object recognition, had decreased tactile startle but not acoustic startle, and females had increased latency on cued training trials in the Morris water maze, but not hidden platform spatial learning trials. Open‐field activity showed small differences in females but not males. The data indicate that the GC‐C KO mouse with proper controls and sample sizes has a moderate cognitive and startle phenotype but has no ADHD‐like phenotype. 相似文献
43.
Objectives: Recently, there has been a resurgence of interest in the interactions between oral conditions and a number of prevalent systemic diseases. The morbidity and mortality of the dependent elderly that result from aspiration pneumonia have been recognized as a major geriatric health problem. The purpose of this study was to gain more information on the microflora of plaque on dentures and to assess the existence of oral infectious pathogens potentially causing the respiratory disease in the dependent elderly. Subjects and Methods: The denture bacterial flora of 50 dependent elderly were examined to identify microorganisms by the culture method. Results: 18 species of microorganisms were detected in denture plaque in this study. A variety of pathogens with the potential to cause respiratory infection pathogens colonized on the dentures of dependent elderly. Conclusion: The results of the present study revealed that bacteria that commonly cause respiratory infection colonized on the dentures of dependent elderly, suggesting that denture plaque may function as a reservoir of potential respiratory pathogens to facilitate colonization on the oropharynx. 相似文献
44.
The chemical compositions of ground water and organic matter in sediments were investigated at a sandy shore of Tokyo Bay, Japan to determine the fate of ground water NO3
–. On the basis of Cl– distribution in ground water, the beach was classified into freshwater (FR)-, transition (TR)-, and seawater (SW)-zones from the land toward the shoreline. The NO3
– and N2O did not behave conservatively with respect to Cl– during subsurface mixing of freshwater and seawater, suggesting NO3
– consumption and N2O production in the TR-zone. Absence of beach vegetation indicated that NO3
– assimilation by higher plants was not as important as NO3
– sink. Low NH4
+ concentrations in ground water revealed little reduction of NO3
– to NH4
+. These facts implied that microbial denitrification and assimilation were the likely sinks for ground water NO3
–. The potential activity and number of denitrifiers in water-saturated sediment were highest in the low-chlorinity part of the TR-zone. The location of the highest potential denitrification activity (DN-zone) overlapped with that of the highest NO3
– concentration. The C/N ratio and carbon isotope ratio (13C) of organic matter in sediment (< 100 -m) varied from 12.0 to 22.5 and from –22.5 to –25.5, respectively. The 13C value was inversely related to the C/N ratio (r
2 = 0.968, n = 11), which was explained by the mixing of organic matters of terrestrial and marine origins. In the DN-zone, the fine sediments were rich in organic matters with high C/N ratios and low 13C values, implying that dissolved organic matters of terrestrial origin might have been immobilized under slightly saline conditions. A concurrent supply of NO3
– and organic matter to the TR-zone by ground water discharge probably generates favorable conditions for denitrifiers. Ground water NO3
– discharged to the beach is thus partially denitrified and fixed as microbial biomass before it enters the sea. Further studies are necessary to determine the relative contribution of these processes for NO3
– removal. 相似文献
45.
We investigated the effect of angiotensin II on prostaglandin E(2) release in human gingival fibroblasts. Stimulation of human gingival fibroblasts with angiotensin II elicited prostaglandin E(2) release in a concentration- and time-dependent manner. Angiotensin III also induced prostaglandin E(2) release, but the effect was weaker than that of angiotensin II. Angiotensin II- and angiotensin III-induced prostaglandin E(2) release was inhibited by AT(1) receptor antagonist FR-130,739, but not AT(2) receptor antagonist PD-123,319. Angiotensin II evoked an increase in intracellular Ca(2+) in fura-2-loaded human gingival fibroblasts. These results suggest that angiotensin II functions as a physiological mediator via Ca(2+)-mobilizing AT(1) receptor activation in human gingival fibroblasts. 相似文献
46.
Tsuji S Ueda K Nishiyama T Hasebe M Yoshikawa S Konagaya A Nishiuchi T Yamaguchi K 《Journal of plant research》2007,120(2):281-290
We determined the complete nucleotide sequence of the chloroplast genome of Selaginella uncinata, a lycophyte belonging to the basal lineage of the vascular plants. The circular double-stranded DNA is 144,170 bp, with
an inverted repeat of 25,578 bp separated by a large single copy region (LSC) of 77,706 bp and a small single copy region
(SSC) of 40,886 bp. We assigned 81 protein-coding genes including four pseudogenes, four rRNA genes and only 12 tRNA genes.
Four genes, rps15, rps16, rpl32 and ycf10, found in most chloroplast genomes in land plants were not present in S. uncinata. While gene order and arrangement of the chloroplast genome of another lycophyte, Hupertzia lucidula, are almost the same as those of bryophytes, those of S. uncinata differ considerably from the typical structure of bryophytes with respect to the presence of a unique 20 kb inversion within
the LSC, transposition of two segments from the LSC to the SSC and many gene losses. Thus, the organization of the S. uncinata chloroplast genome provides a new insight into the evolution of lycophytes, which were separated from euphyllophytes approximately
400 million years ago.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
47.
Ogata Y Nakao S Shimizu E Matsuda-Honjyo Y Yamazaki M Furuyama S Sugiya H 《Cell biology international》2003,27(8):689-693
Bradykinin (1 microM) and histamine (100 microM) evoked an initial transient increase and a subsequent sustained increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in fura-2-loaded human gingival fibroblasts, which may be attributed to Ca(2+) release from intracellular stores and Ca(2+) entry from extracellular sites, respectively. In fibroblasts pretreated with tyrosine kinase inhibitors such as herbimycin A (1 microM) and tyrphostin 47 (20 microM), the sustained level of [Ca(2+)](i) induced by bradykinin and histamine increased, but not the initial peak level. In the absence of external Ca(2+), bradykinin and histamine induced only the transient increase in [Ca(2+)](i), but a subsequent addition of Ca(2+) to the medium resulted in a sustained increase in [Ca(2+)](i) caused by Ca(2+)entry. Thapsigargin, an inhibitor of Ca(2+)-ATPase in inositol 1,4,5-trisphosphate-sensitive Ca(2+) stores, mimicked the effect of bradykinin and histamine. In the fibroblasts pretreated with tyrosine kinase inhibitors, the bradykinin-, histamine- and thapsigargin-induced Ca(2+) entry was clearly enhanced, but not the transient [Ca(2+)](i) increase. Tyrosine phosphatase inhibitor benzylphosphonic acid (200 microM) had no effect on Ca(2+)entry or transient [Ca(2+)](i) increase. These results suggest that tyrosine phosphorylation is involved in Ca(2+) entry in human gingival fibroblasts. 相似文献
48.
Isolation and properties of fecal proteins and fecal alkaline phosphatase from germfree and conventional rats. 下载免费PDF全文
Fecal proteins from germfree and conventional rats were isolated. The proteins from the two kinds of feces differed in molecular weight, judging from Sephadex gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The conventional feces contained a greater amount of high-molecular-weight and a lesser amount of low-molecular-weight proteins than did the germfree feces. The fecal proteins of both kinds contained carbohydrates. Both feces contained considerable enzyme activity. The germfree feces contained extremely high activity in alkaline phosphatase and leucine aminopeptidase. Both feces showed the same level of trehalase activity. The conventional feces contained higher levels of activity of protease and acid phosphatase than did the germfree feces. Lactase activity was observed only in the conventional feces. The fecal alkaline phosphatase resembled the intestinal enzyme in response to L-phenylalanine inhibition and urea denaturation. From these results it was inferred that the germfree feces contained some of the intestinal proteins and that the conventional feces contained bacterial proteins in addition to intestinal proteins. 相似文献
49.
Aims
Dietary flavonoid intake shows a significant inverse association with mortality from coronary heart disease, incidence of myocardial infarction and stroke. Quercetin is one of the most common flavonoids in our diet and has several favorable biological activities. Quercetin glucosides, which are enzymatically trans-glycosylated isoquercitrin, have high water-solubility and bioavailability compared with quercetin. Here, we investigated the effects of quercetin glucosides on collateral development in a murine hindlimb ischemia model.Main methods
We induced hindlimb ischemia in 24- to 32-week-old male C3H/HeJ mice by resecting the right femoral artery. Then, 0.5% carboxymethyl cellulose (control) or quercetin glucosides (100 mg/kg/day) were administered daily by gavage. Blood flow was monitored weekly by laser Doppler imaging.Key findings
Recovery of blood flow to the ischemic leg was significantly enhanced by quercetin glucosides (blood flow ratio at 4 weeks: control, 0.57 ± 0.11; quercetin glucosides, 0.95 ± 0.10, p < 0.05). Furthermore, anti-CD31 immunostaining revealed that quercetin glucosides increased capillary density in the ischemic muscle (control, 200 ± 24/mm2; quercetin glucosides, 364 ± 41/mm2, p < 0.01). Quercetin glucosides did not promote tumor growth. The beneficial effect of quercetin glucosides was abrogated in eNOS-deficient mice.Significance
These results suggest that quercetin glucosides may have therapeutic potential to promote angiogenesis in ischemic tissue. 相似文献50.
Yoshimura T Tsuge K Sumi T Yoshiki M Tsuruta Y Abe S Nishino S Sanematsu S Koganemaru K 《Bioscience, biotechnology, and biochemistry》2006,70(4):1026-1028
Marine microorganisms degrading porphyran (POR) were found on the surface of thalli of Porphyra yezoensis. Fifteen crude microorganism groups softened and liquefied the surface of agar-rich plate medium. Among these, 11 microorganism groups degraded porphyran that consisted of sulfated polysaccharide in Porphyra yezoensis. Following isolation, 7 POR-degradable microorganisms were isolated from the 11 POR-degradable microorganism groups. 相似文献