Endotoxin: stimulation of bone resorption in tissue culture

Bacterial endotoxins can stimulate the release of previously incorporated calcium-45 and tritiated proline from fetal rat bone in tissue culture. Endotoxin from Bacteroides melaninogenicus, an organism regularly found in the gingival crevice of man, produces a response similar to parathyroid hormone and is effective at doses as low as 0.1 microgram per milliliter. This response is inhibited by serum and dependent upon the presence of albumin. Endotoxins may play a role in the bone loss characteristic of human periodontal disease.     

2-Thiophenecarboxylic acid: inhibitor of bone resorption in tissue culture

In tissue culture 2-thiophenecarboxylic acid inhibited both spontaneous resorption of bone and that induced by parathyroid hormone. Its action was to inhibit calcium transfer out of bone.     

1,25-dihydroxycholecalciferol: a potent stimulator of bone resorption in tissue culture

1,25-Dihydroxycholecalciferol (DHCC), isolated from kidney homogenates incubated with 25-hydroxycholecalciferol (HCC), stimulated the release of previously incorporated (45)45Ca from fetal rat bones in organ culture, at concentrations of 10(-10) to 10(-8)M. The dose response curves for 1,25-DHCC and 25-HCC, the parent compound, are parallel, but 1,25-DHCC is about 100 times as potent on a weight basis. Brief exposure to maximum doses of either agent leads to prolonged bone resorption.     

Thyrocalcitonin inhibition of bone resorption induced by parathyroid hormone in tissue culture

Added thyrocalcitonin greatly diminished parathyroid-hormone-induced resorption of bone in tissue culture. The results indicate that bone is primary site of action of thyrocalcitonin.     

Diphosphonates inhibit hydroxyapatite dissolution in vitro and bone resorption in tissue culture and in vivo

Two diphosphonates containing the P-C-P bond, Cl(2)C(PO(3)HNa)(2), and H(2)C(PO(3)HNa)(2) retard the rate of dissolution of apatite crystals in vitro. They inhibit bone resorption induced by parathyroid extract in mouse calvaria in tissue culture and in thyroparathyroidectomized rats in vivo.     

Carbonic anhydrase and bone remodeling: sulfonamide inhibition of bone resorption in organ culture

Five sulfonamide inhibitors of carbonic anhydrase inhibited parathyroid hormone-induced resorption of bone in organ culture. The relative activities of the sulfonamides as resorption inhibitors were such as to suggest the presence of a functional carbonic anhydrase system in bone linked to the mechanism of bone resorption.     

Contact-mediated bone resorption by human monocytes in vitro

Human circulating monocytes in tissue culture are capable of resorbing devitalized adult and fetal bone. An important component of this process is the adhesion of the cells to the mineralized substrate and the localized removal of matrix from beneath the attached cells. The process appears to involve both release of lysosomal enzymes onto the substrate and intracellular accumulation (transport) of resorbed matrix.     

植物组织培养中降低培养基成本的研究

在马铃薯、菊花和满天星的发根阶段研究了用自来水代替蒸馏水、白糖代替蔗糖的可行性．结果表明：马铃薯、菊花和满天星培养苗的生长在蔗糖与白糖、蒸馏水与自来水的处理间无显著性差异，因此规模化生产上配制培养基时用白糖取代蔗糖，自来水取代蒸馏水完全可行．     

Stimulation of bone resorption in vitro by synthetic transforming growth factor-alpha

Experiments were conducted to test the hypothesis that tumor-derived transforming growth factor-alpha (TGF-alpha) is responsible for the increased bone resorption and hypercalcemia seen in some malignant diseases. Homogeneous synthetic TGF-alpha prepared by the solid-phase synthesis method stimulated bone resorption directly in vitro in a concentration-dependent manner. Incubation times of 72 hours or more were required to stimulate resorption, which is similar to the time course of bone resorption by epidermal growth factor.     

茶树组织培养研究进展

对茶树组织培养技术在茶树种苗快速繁殖、辅助育种、次生代谢产物生产等方面的应用进行综述,阐述了以茶树根、茎、花、种子等为外植体开展的组织培养的培养基研究,并提出组织培养过程中产生褐化、污染的原因及控制对策。     

鹅掌楸属植物组织培养研究进展

近年来,我国对鹅掌楸属植物种苗的需求不断增加,但由于鹅掌楸属植物花期不遇,种子发芽率低,扦插、嫁接繁殖比较困难,因此组织培养技术成为鹅掌楸属植物种苗快速繁殖的一条重要途径。文章从外植体的选择、初代和继代培养、培养条件、生根培养及体细胞胚胎发生等方面综述了鹅掌楸属植物组织培养的研究成果,分析鹅掌楸属植物组织培养中存在的问题,探讨鹅掌楸属植物组织培养研究的方向。今后将继续研究解决鹅掌楸属植物组培过程中生根难、褐化等问题,加强在原生质体水平上对鹅掌楸属植物再生繁殖体系及其遗传转化体系的研究;研究利用组织培养技术对鹅掌楸属植物进行种质保存,从而为其种质资源的保存和利用、新品种的选育提供技术支持。     

花生组织培养研究进展

花生组织培养对于品种改良、新品种繁殖、遗传转化和种质保存等具有重要意义．本文概述了花生苗的再生培养、体细胞胚的诱导培养、花药培养、远缘杂种胚营救培养、原生质体培养和遗传转化的研究进展,并展望了花生组织培养未来的发展     

Radiation leukemia virus: quantitative tissue culture assay

Radiation leukemia virus does not propagate in tissue cultures from either Swiss or C57BL mouse embryos, but it does augment focus formation by the defective Moloney leukemia pseudotype of murine sarcoma virus in Swiss mouse cells and thus can be quantitatively assayed.     

蝴蝶兰组织培养研究进展

蝴蝶兰是一种具有广阔市场前景的花卉植物,采用组培快繁技术进行种苗繁殖,是目前大规模生产蝴蝶兰的唯一途径。对近年来蝴蝶兰(Phalaenopsis spp.)组织培养的研究进展进行综述,着重阐述蝴蝶兰组织培养中外植体、培养基和培养条件等方面,以期为蝴蝶兰从业者提供帮助。最后,分析了蝴蝶兰组培快繁中存在的问题,并对其研究与开发前景进行展望。     

Chloramphenicol: effects on mouse myeloma cells in tissue culture

Within 36 hours of being administered, chloramphenicol (50 micrograms per milliliter) inhibits by 50 percent the rate of protein synthesis in mouse myeloma cells grown in suspension culture. Although there is a decrease in the amount of globulin synthesized, the rate of synthesis per cell is unchanged; the observed decrease is traced to the inhibition of cell proliferation caused by chloramphenicol.     

柠条组织培养技术

试验以小叶锦鸡儿成熟种子为试材,1/2MS培养基建立起了无菌苗,并取其茎段离体培养获得丛生芽及完整植株.探讨了种子不同的灭菌时间及pH值、培养基和植物生长调节剂对柠条试管苗成活率及生长状况的影响,结果表明:种子以0.1%升汞8min灭菌效果最为理想;微酸性(pH6.5)条件下,有利于柠条的增殖;MS+IAA0.2mg.L-1+6-BA0.2mg.L-1组合增殖效果最佳;MS+IAA0.4mg.L-1+IBA0.2mg.L-1为最优生根培养基.     

试管苗玻璃化现象的研究进展

玻璃化是植物组织培养过程中特有的一种生理失调或生理病变,普遍发生于多种植物中。玻璃化试管苗呈透明或半透明的水浸状,叶片卷曲畸形,分化及存活能力低,无法进行继代培养及驯化移栽,给种苗商业化生产造成了严重的经济损失,也限制了组织培养技术在种质资源保存及基因工程育种中的应用。目前,对玻璃化发生的机制尚没有统一的认识。本文对玻璃化现象、发生机制以及预防措施等相关研究进行了综述,以期为研究玻璃化发生发展的机制并开发有效的防控措施提供借鉴。     

非洲菊组织培养研究进展

综述了近年来非洲菊组织培养的研究进展,包括外植体选择与灭菌,愈伤组织的诱导分化,试管苗继代培养,生根培养和驯化移栽等方面;总结了目前非洲菊组织培养过程中主要存在的问题,以及多效唑(PP333)、La3+、封口膜对非洲菊组织培养的影响;指出了非洲菊组织培养中值得继续深入研究的方面。     

西瓜组织培养研究进展

简要综述了西瓜的芽、子叶、胚、花药等外植体及原生质体离体培养植株再生的研究进展,并对组织培养技术在无籽西瓜新品种推广中的应用提出几点建议.