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1.
Two fractions isolated from cultured lymphoblastoid cells stimulated mucus secretion from the urn cell complex of the marine invertebrate Sipunculus nudus. The activity detected in the nuclear fraction was trypsin-sensitive, and it increased in response to specific nucleotides. 相似文献
2.
Cupulae on the surface of the sensory epithelium of canal neuromasts of the shark lateralis system have been demonstrated. They are mounds of mucoid material secreted primarily by the supporting cells of the neuromast epithelium. Individual columns of mucus in fixed, stained sections produce striations perpendicular to the neuromast surface. The hair of the sensory cell is embedded in mucus at the bases of coalescing columns produced by a group of surrounding supporting cells. There is evidence that mucus production is continuous and is accompanied by regeneration of secretory cells and elimination of necrotic cells at the distal surface. It follows that cupular material is being discarded either intermittantly or continually, along with trapped cell debris and other detritus. 相似文献
3.
B Button LH Cai C Ehre M Kesimer DB Hill JK Sheehan RC Boucher M Rubinstein 《Science (New York, N.Y.)》2012,337(6097):937-941
Mucus clearance is the primary defense mechanism that protects airways from inhaled infectious and toxic agents. In the current gel-on-liquid mucus clearance model, a mucus gel is propelled on top of a "watery" periciliary layer surrounding the cilia. However, this model fails to explain the formation of a distinct mucus layer in health or why mucus clearance fails in disease. We propose a gel-on-brush model in which the periciliary layer is occupied by membrane-spanning mucins and mucopolysaccharides densely tethered to the airway surface. This brush prevents mucus penetration into the periciliary space and causes mucus to form a distinct layer. The relative osmotic moduli of the mucus and periciliary brush layers explain both the stability of mucus clearance in health and its failure in airway disease. 相似文献
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5.
DNA-membrane complex: macromolecular content and stimulation of enzymatic activity by polyadenylic acid 总被引：2，自引：0，他引：2
A DNA-cell membrane complex has been isolated from cell suspensions of virulent pneumococci by sarcosyl lysis followed by centrifugation on a sucrose gradient. When polyadenylic acid plus the eight naturally occurring deoxyribonucleosides and deoxyribonucleotides are added to cell suspensions, the percentage of total DNA in the complex increases with incubation time. This increase is not observed in unsupplemented cell suspensions. However, the percentages of RNA, protein, and phospholipid do not increase with incubation time in either supplemented or control complexes. A variety of deoxyribonucleotide kinases and the DNA polymerase are also detected in the DNA-membrane complex, and their specific activities are greater in complexes extracted from supplemented cell suspensions than in those extracted from controls. 相似文献
6.
[目的]研究纳豆芽孢杆菌在对健康和鳗弧菌感染牙鲆肠粘液粘附中的作用。[方法]应用5 mol/L LiCl提取纳豆芽孢杆菌表面蛋白,利用蛋白印迹法鉴定在纳豆芽孢杆菌表面蛋白中分子量及参与粘附的特异蛋白。[结果]对提取的纳豆芽孢杆菌表面蛋白进行SDS-PAGE后,发现仅出现一条明显的主要蛋白条带,分子量为29.58 kDa。经蛋白印迹分析,该蛋白质参与了健康和鳗弧菌感染牙鲆肠粘液的粘附过程;纳豆芽孢杆菌全菌蛋白在健康和鳗弧菌感染牙鲆肠粘液中有一个相同的粘附受体,蛋白分子量为13.91 kDa;健康个体还有一个粘附受体,分子量是29.86 kDa。[结论]纳豆芽孢杆菌的表面蛋白在对牙鲆肠粘液的粘附过程中起着重要作用。 相似文献
7.
鲶鱼体表黏液特性的初步研究 总被引：1，自引：0，他引：1
对鲶鱼体表黏液活性成分、抑菌特性进行研究,并对蛋白类物质和多糖类物质含量进行测定,结果表明:(1)使用G-200葡聚糖凝胶层析法对鲶鱼体表黏液活性成分进行分离,无法得到纯化的单一物质,在以后的试验中需要寻找新的分离纯化方法。(2)鲶鱼体表黏液对藤黄色葡萄球菌、大肠杆菌、枯草杆菌抑菌效果不明显。(3)鲶鱼体表黏液中含有的蛋白类物质含量占黏液干重的40%左右,多糖类物质约占黏液干重的4.2%。 相似文献
8.
黄鳝基因组DNA一直采用抽血或剪取肌肉来提取,但是采血或剪取肌肉后黄鳝成活率很低。为了保留亲本,尝试从黄鳝体表粘液中提取DNA,并采用紫外分光光度计对提取到的DNA的纯度和浓度进行了检测。结果表明,用蛋白酶K消化,酚仿抽提后从粘液中得到的DNA的纯度与从肌肉中提取到的相差不大,但是提取到的量较少。为了验证提取的DNA是不是黄鳝基因组DNA,用黄鳝actin引物和18S r RNA基因引物扩增之后检测到了粘液中的较亮的DNA片段。为了进一步确认检测到的是黄鳝的DNA,我们又对得到的DNA进行了扩增,并得到的产物进行了克隆和测序。结果表明,粘液中提取到的DNA是黄鳝的基因组DNA。随后又选择了60尾黄鳝,提取其粘液之后对其成活率进行统计,养殖1个月后黄鳝的成活率都在95%以上。此黄鳝体表粘液提取DNA方法能提取高质量的DNA,可用于用于PCR鉴定。 相似文献
9.
Velcich A Yang W Heyer J Fragale A Nicholas C Viani S Kucherlapati R Lipkin M Yang K Augenlicht L 《Science (New York, N.Y.)》2002,295(5560):1726-1729
The gastrointestinal tract is lined by a layer of mucus comprised of highly glycosylated proteins called mucins. To evaluate the importance of mucin in intestinal carcinogenesis, we constructed mice genetically deficient in Muc2, the most abundant secreted gastrointestinal mucin. Muc2-/- mice displayed aberrant intestinal crypt morphology and altered cell maturation and migration. Most notably, the mice frequently developed adenomas in the small intestine that progressed to invasive adenocarcinoma, as well as rectal tumors. Thus, Muc2 is involved in the suppression of colorectal cancer. 相似文献
10.
[目的]研究黏红酵母(Rhodotorula glutinis)、鼠李糖乳杆菌(Lactobacillus rhamnosus)、纳豆芽孢杆菌(Bacillus natto)、嗜酸乳杆菌(Lactobacillus casei)对牙鲆肠黏液的黏附能力,探讨黏红酵母在牙鲆肠道中的定植规律及对牙鲆抗病能力的影响。[方法]采用体外黏液黏附模型测定上述4株益生菌的黏液黏附能力,平板菌落计数法测定黏红酵母在肠道的数量。[结果]黏红酵母对牙鲆肠黏液黏附能力最强,其次是鼠李糖乳杆菌,纳豆芽孢杆菌黏附能力最弱。投喂含黏红酵母饲料的牙鲆肠道其酵母数量达到了103～104cfu/g内含物。鳗弧菌攻毒后,对照组牙鲆死亡率显著高于黏红酵母组。[结论]黏红酵母在牙鲆肠道具有较好定植潜能并能降低牙鲆因弧菌引起的死亡率,因此具有较好的应用前景。 相似文献
11.
Female steroid hormones and target cell nuclei 总被引：58，自引：0，他引：58
12.
Autoimmune diseases: the failure of self tolerance 总被引：34，自引：0，他引：34
The ability to discriminate between self and nonself antigens is vital to the functioning of the immune system as a specific defense against invading microorganisms. Failure of the immune system to "tolerate" self tissues can result in pathological autoimmune states leading to debilitating illness and sometimes death. The induction of autoimmunity involves genetic and environmental factors that have focused the attention of researchers on the trimolecular complex formed by major histocompatibility complex molecules, antigen, and T cell receptors. Detailed molecular characterization of these components points to potential strategies for disease intervention. 相似文献
13.
Programmed cell death of T cells signaled by the T cell receptor and the alpha 3 domain of class I MHC 总被引：8，自引：0，他引：8
As well as being activated or rendered unresponsive, mature T lymphocytes can be deleted, depending on the signals received by the cell. Deletion by programmed cell death (apoptosis) is triggered if a T cell that has received a signal through its T cell receptor complex also receives a signal through the alpha 3 domain of its class I major histocompatibility complex (MHC) molecule. Such a signal can be delivered by a CD8 molecule, which recognizes the alpha 3 domain, or by an antibody to this domain. Precursors of both cytotoxic T lymphocytes (CTL's) and T helper cells are sensitive to this signal but become resistant at some point before completing differentiation into functioning CTL's or T helper cells. Because CTL's carry CD8, they can induce cell death in T cells that recognize them. This pathway may be important in both removal of autoreactive T cells and immunoregulation. 相似文献
14.
HIV-1-infected T cells show a selective signaling defect after perturbation of CD3/antigen receptor 总被引：16，自引：0，他引：16
The binding of antigen or monoclonal antibody to the T cell receptor for antigen or the closely associated CD3 complex causes increases in the concentration of intracellular ionized calcium and subsequent cell proliferation. By measuring second messenger production in primary cultures of human immunodeficiency virus (HIV-1)--infected T cells stimulated with monoclonal antibodies specific for either CD3 or CD2, a specific impairment of membrane signaling was revealed. The HIV-1--infected T cells were unable to mobilize Ca2+ after stimulation with anti-CD3, whereas CD2-induced calcium mobilization remained intact. Furthermore, the HIV-1--infected cells proliferated poorly after CD3 stimulation, although the cells retained normal DNA synthesis in response to interleukin-2 stimulation. These results show that the signals initiated by CD2 and CD3 can be regulated independently within the same T cell; uncoupling of signal transduction after antigen-specific stimulation provides a biochemical mechanism to explain, in part, the profound immunodeficiency of patients with HIV-1 infection. 相似文献
15.
为比较分娩后患子宫内膜炎奶牛和健康奶牛血清及子宫黏液中IgA、IgM和IgG的变化,采用酶联免疫吸附测定法分别对奶牛血清和子宫黏液中IgA、IgM和IgG的质量浓度进行定量检测。结果表明,患病奶牛血清中的IgA和健康奶牛子宫黏液中的IgA持续降低,子宫黏液中IgA先降低后升高,健康奶牛血清中IgA变化不大;患病奶牛和健康奶牛子宫黏液和血清中IgG均先降低后升高;健康奶牛血清和子宫黏液中IgM先降低后升高,患病奶牛子宫黏液中IgM先升高后降低,后又升高,患病奶牛血清中IgM逐渐降低;患病奶牛血清中IgG始终高于健康奶牛的,说明IgG在全身体液免疫中发挥主要作用;患病奶牛子宫黏液的IgA和IgM高于健康奶牛,说明IgA和IgM在子宫局部免疫中发挥主要作用。 相似文献
16.
Sonnenburg JL Xu J Leip DD Chen CH Westover BP Weatherford J Buhler JD Gordon JI 《Science (New York, N.Y.)》2005,307(5717):1955-1959
17.
呋喃唑酮对饲养水及草鱼体表粘液中菌群的影响 总被引：6，自引：2，他引：4
对饲养水中泼洒不同浓度（０．２ｍｇ／Ｌ、０．５ｍｇ／Ｌ和１．０ｍｇ／Ｌ）的呋喃唑酮后,研究了饲养水及草鱼体表粘液中好氧与兼性厌氧细菌的数量及组成变化。结果表明：用药前,饲养水及粘液中的菌群主要有Ａｅｒｏｍｏｎａｓ、Ｅｎｔｅｒｏｂａｃｔｅｒｉａｃｅａｅ、Ｖｉｂｒｉｏ、Ｆｌａｖｏｂａｃｔｅｒｉｕｍ、Ａｃｉｎｅｔｏｂａｃｔｅｒ、Ｐｓｅｕｄｏｍｏｎａｓ、Ｃｏｒｙｎｅｂａｃｔｅｒｉｕｍ、Ｓｔａｐｈｙｌｏｃｏｃｕｓ和Ｂａｃｉｌｕｓ,此外,水体中还检测到Ｍｉｃｒｏｃｏｃｕｓ和Ａｌｃａｌｉｇｅｎｅｓ。水体及粘液中的细菌数量在用药后１２ｈ或２４ｈ时降至最低,在４８ｈ或９６ｈ时恢复到原来的水平。用药后,水体及粘液中的优势菌群未发生改变,但Ｆｌａｖｏｂａｃｔｅｒｉｕｍ的比例显著增加,Ａｅｒｏｍｏｎａｓ、Ｖｉｂｒｉｏ和Ｅｎｔｅｒｏｂａｃｔｅｒｉａｃｅａｅ明显减少,Ｐｓｅｕｄｏｍｏｎａｓ和Ａｃｉｎｅｔｏｂａｃｔｅｒ则未能检测到,其他各类群的比例也有一定的变化。菌群的变化速度与用药浓度有关。 相似文献
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研究两歧双歧杆菌、禽大肠杆菌O78、大肠杆菌ATCC25922、鸡白痢沙门氏菌和鼠伤寒沙门氏菌与肉鸡不同肠段粘液糖蛋白的粘附性能，探讨两歧双歧杆菌对四种病原菌的粘附排斥作用。结果表明，在不同的肠道部位，两歧双歧杆菌、鸡白痢沙门氏菌和鼠伤寒沙门氏菌与肠粘液糖蛋白的粘附能力不同，而禽大肠杆菌O78、大肠杆菌ATCC25922在各肠段粘液上的粘附性能相近；在相同的肠道部位，所试菌与肠粘液糖蛋白的粘附能力有差异，其中两歧双歧杆菌的粘附作用最强；肠粘液糖蛋白经两歧双歧杆菌处理后，禽大肠杆菌O78、大肠杆菌ATCC25922和鸡白痢沙门氏菌的粘附作用受到抑制，而鼠伤寒沙门氏菌在十二指肠、空肠粘液上的粘附率未见下降。 相似文献
19.
盐度和温度对大菱鲆幼鱼抗氧化酶活性的影响 总被引：1，自引：0，他引：1
采用两因素交叉分组的方法,研究了温度和盐度对大菱鲆Scophthalmus maximus幼鱼行为活动、摄食、存活情况以及体表黏液、血液、鳃、肝脏中抗氧化酶活力的影响.结果表明:水温(17、20、23、25、28℃)和盐度(5、10、20、30、40)对大菱鲆幼鱼摄食、死亡率有显著影响(P＜0.05),在水温为17、20℃与盐度为20、30的组合条件下,大菱鲆幼鱼的摄食积极性以及存活率较高,显著高于其他组(P＜0.05);温度和盐度对大菱鲆幼鱼SOD、CAT与GP-X活力有显著影响(P＜0.05);当温度一定,盐度变化的条件下,肝脏、鳃、血清和黏液中的各种酶活力在正常海水盐度(30)时活力较低,并随盐度由30起降低或升高而均出现升高的趋势;当盐度一定,温度变化的条件下,随着水温的升高,各组织中的酶活力变化规律不显著;通过分析温度与盐度交互作用对各组织不同酶活的变化以及生命表征现象,得出了最适生存阈值,即大菱鲆幼鱼的适宜生活水温为17～20℃,适宜生活盐度为20～30. 相似文献
20.
用酚灭活的柱状嗜纤维菌和从该菌体提取的菌体脂多糖浸泡接种２０～２５ｇ的草鱼鱼种，共浸泡２次间隔一周。通过检测受免鱼体血清、肠和体表粘液中凝集抗体效价、血液中吞噬细胞的吞噬活性和采用活菌攻毒的方法，探讨了浸泡免疫接种疫苗对预防草鱼细菌性烂鳃病的效果。结果表明，受免鱼体与对照鱼相比，血清、肠和体表粘液中凝集抗体效价和血液中吞噬细胞的吞噬活性都有明显上升。经活菌攻毒后，酚灭活柱状嗜纤维菌疫苗免疫组免疫保护率达３０％，而脂多糖疫苗免疫组免疫保护率为５５％。 相似文献