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51.
The microstructural characteristics of the capture thread production from silk glands in the orb web spiders were analyzed using scanning and transmission electron microscopes. Sticky and gluey capture threads of the web are originated from the silks of two flagelliform glands and four aggregate glands. They supply precursors of the secretory silks to a pair of characteristic “triad” spinning units on the posterior spinnerets. The aggregate gland is composed of large and multi‐lobed secretory region and thick excretory duct surrounded by large irregular nodules. The excretory duct of this gland basically consists of three superposed types of cells which are inner columnar epithelium, nodule forming cells and outer connectives. The nodules contain numerous mitochondria and glycogen particles within their cytoplasm and they are surrounded by the same sheath of thin connective tissues. Secretory region of the aggregate gland which produce water‐soluble components of the capture thread comprises discrete secretory vesicles and extensive rough endoplasmic reticulum. Characteristically, secretory droplets are formed without involvement of the Golgi complexes, suggesting that they do not play an important role in the processing of the capture threads. However the electron densities and internal textures of the granules are observed with diverse according to their maturation level. Finally, the secretory products are released by the mechanism of apocrine secretion losing part of their cytoplasm during this process. 相似文献
52.
The thread blight disease of broad leaved trees caused byCylindrobasidium argenteum occurred in laurel forests over 20 yr old after clear cutting in Kyushu. Finding fruit bodies of the causal fungus was possible
but very difficult in the forests. In inoculation tests using spores and infected branches harvested in the forests, we succeeded
in transmission only with branches. In the forests, the disease is transmitted almost entirely by contact with infected branches.
During 1989 to 1992 we found four brown-eared bulbul nests containing branches infected with the disease. In one nest, mycelia
of the fungus had been transmitted to the host tree. The occurrence of the disease in forests over 20-yr-old was considered
to be due to the nesting of birds in trees which provided the necessary height and closed environment. 相似文献
53.
目的:探讨老年男性晨尿阿尔茨海默病相关神经丝蛋白(AD7c-NTP)水平与轻度认知障碍(MCI)发病之间关系。方法:收集341例住院老年男性患者中段晨尿,采用双抗体夹心法测定尿液AD7c-NTP浓度。同时,对患者进行痴呆系列测试、行头颅CT和(或)MRI检查。根据测试结果剔除20例早老性痴呆患者,剩余321例患者根据测试及检查结果分为对照和MCI组,两组病例数分别为270例和51例,分析尿液AD7c-NTP浓度与年龄和MCI发病之间关系。结果:老年男性晨尿AD7c-NTP浓度呈偏态分布,测定结果中位数为0.475μg/L(0.001μg/L-8.85μg/L);对照组年龄76.0±9.0岁,AD7c-NTP测定结果中位数为0.467μg/L(0.001μg/L-8.85μg/L);MCI组51例年龄85.7±8.2岁,AD7c-NTP测定结果中位数为0.862μg/L(0.10μg/L-8.20μg/L);两组年龄之间存在显著差异(P=0.000);晨尿AD7c-NTP浓度与年龄的Spearman相关系数为0.267(P=0.00)。未考虑年龄影响时,两组ln(AD7c-NTP)之间差异有显著(P=0.041);考虑年龄影响后,两组ln(AD7c-NTP)之间差异显著性消失(P=0.604)。结论:晨尿AD7c-NTP浓度与年龄相关,AD7c-NTP与MCI发病之间关系需进一步研究。 相似文献
54.
Foot tissue of the green mussel Perna viridis contains a variety of byssal precursor proteins with the unusual redox-active amino acid, Dopa (L-β-3,4-dihydroxyphenyl-α-alanine). Eight proteins were detectable in acidic extracts of the Perna foot by a redox cycling assay with nitroblue tetrazolium. In one of these, however, P. viridis foot protein-1 (Pvfp-1), activity was not due to Dopa, but to another redox-active derivative. Based on specific colorimetric derivatization with Arnow's reagent, ninhydrin and phenylisothiocyanate (Edman), mass spectrometry, the redox-active derivative in Pvfp-1 is not consistent with any known modification. Another uncommon modification of Pvfp-1 involves O-glycosylation of threonine by mannose, glucose or fucose. As in previously characterized fp-1s, the primary sequence of the Pvfp-1 (apparent mass 89?kDa) has two consensus decapeptide motifs; one is APPKPX1TAX2K and the other is APPPAX1TAX2K, where P is Pro/Hyp, and X1 and X2 are difucosylated threonine and a redox sensitive derivative of tyrosine or Dopa, respectively. Of these two unusual residues, X2 is unique to Pvfp-1, whereas O-glycosylated Thr has been previously detected in freshwater mussel fp-1. The sequence homology of Pvfp-1 with the common structural motifs of the fp-1 protein family strongly suggests that the Pvfp-1 functions as the byssal coating (lacquer) protein. 相似文献
55.
摘要 目的:探讨与分析浮针埋线联合推拿疗法对神经根型颈椎病疗效及对颈椎活动度、生理曲度变化的影响。方法:2019年2月到2021年6月选择在本院诊治的神经根型颈椎病患者105例作为研究对象,根据1:1简单分配原则把患者分为浮针组53例与对照组52例。对照组给予推拿治疗,浮针组在对照组治疗的基础上给予浮针埋线治疗,两组都治疗观察21 d,记录患者颈椎活动度、生理曲度变化情况。结果:治疗后浮针组的总有效率为98.1 %,与对照组的86.5 %相比有明显提高(P<0.05)。浮针组与对照组治疗后的颈椎活动度评分明显低于治疗前,浮针组与对照组相比也明显降低(P<0.05)。浮针组与对照组治疗后的疼痛视觉模拟评分法(VAS)评分明显低于治疗前,颈椎日本骨科协会评估治疗分数(JOA)评分明显高于治疗前,治疗后浮针组与对照组对比也有明显差异(P<0.05)。浮针组与对照组治疗后的颈椎生理曲度明显高于治疗前,浮针组也明显高于对照组(P<0.05)。结论:浮针埋线联合推拿疗法在神经根型颈椎病患者的应用能促进缓解疼痛,改善颈椎功能,能提高治疗疗效,改善患者的颈椎活动度,还可促进颈椎生理曲度恢复正常。 相似文献
56.
简述Claraia tumida(Patte)的研究历史,依据共模标本再度描述研究其右壳的足丝凹口特征。《中国的瓣鳃类化石》一书中曾描述的本种的半轮状"足丝凹口",实际上是完全依照裂缝或破口的痕迹修剪而成,与真正的足丝凹口并无关系。这一虚假的"足丝凹口"近年来曾被广泛引用,企图借以证明本种和克氏蛤属也发育了Claraioides型足丝凹口。凡是由这个虚假的"足丝凹口"派生而来的观点和推论都不能成立。 相似文献
57.
58.
Bjoern Bartels Philipp Cueni Dieter Muri Matthias Koerner 《Bioorganic & medicinal chemistry》2018,26(4):970-976
A scalable 5-step synthesis of the diazacarbazole derivative 1 used as tau PET tracer precursor is reported. Key features of this synthesis include a Buchwald-Hartwig amination, a Pd catalyzed CH activation and a Suzuki-Miyaura cross-coupling. 相似文献
59.
Dr. Sc. Jacques Gilloteaux 《Cell and tissue research》1975,161(4):511-519
Summary Studies on the intrinsic innervation of the anterior byssal retractor muscle (ABRM) in Mytilus edulis L. were continued at the ultrastructural level. Electron micrographs show nerve processes ensheathed by glio-interstitial cells running between muscle fibers. The glio-interstitial cells may represent all the types of osmiophilic cells previously described by the light microscopic ZIO technique in the anterior byssal retractor muscle. 相似文献
60.
A. EL-HAMDAOUI M. REDONDO-NIETO R. RIVILLA I. BONILLA & L. BOLAÑOS 《Plant, cell & environment》2003,26(7):1003-1011
The effects of modifying boron (B) and calcium (Ca2+) concentrations on the establishment and development of rhizobial symbiosis in Pisum sativum plants grown under salt stress were investigated. Salinity almost completely inhibited the nodulation of pea plants by Rhizobium leguminosarum bv. viciae 3841. This effect was prevented by addition of Ca2+ during plant growth. The capacity of root exudates derived from salt‐treated plants to induce Rhizobium nod genes was not significantly decreased. However, bacterial adsorption to roots was highly inhibited in plants grown with 75 mM NaCl. Moreover, R. leguminosarum 3841 did not grow in minimal media containing such salt concentration. High Ca2+ levels enhanced both rhizobial growth and adsorption to roots, and increased nodule number in the presence of high salt. Nevertheless, the nodules developed were not functional unless the B concentration was also increased. Because B has a strong effect on infection and cell invasion, these processes were investigated by fluorescence microscopy in pea nodules harbouring a R. leguminosarum strain that expresses green fluorescent protein. Salt‐stressed plants had empty nodules and only those treated with high B and high Ca2+ developed infection threads and exhibited enhanced cell and tissue invasion by Rhizobium. Overall, the results indicate that Ca2+ promotes nodulation and B nodule development leading to an increase of salt tolerance of nodulated legumes. 相似文献