共查询到20条相似文献，搜索用时 125 毫秒
1.
Heart regeneration in zebrafish 总被引：4，自引：0，他引：4
Cardiac injury in mammals and amphibians typically leads to scarring, with minimal regeneration of heart muscle. Here, we demonstrate histologically that zebrafish fully regenerate hearts within 2 months of 20% ventricular resection. Regeneration occurs through robust proliferation of cardiomyocytes localized at the leading epicardial edge of the new myocardium. The hearts of zebrafish with mutations in the Mps1 mitotic checkpoint kinase, a critical cell cycle regulator, failed to regenerate and formed scars. Thus, injury-induced cardiomyocyte proliferation in zebrafish can overcome scar formation, allowing cardiac muscle regeneration. These findings indicate that zebrafish will be useful for genetically dissecting the molecular mechanisms of cardiac regeneration. 相似文献
2.
向日葵(Helianthus annuus L.)不同外植体组织培养及其再生的研究 总被引：3，自引：0，他引：3
【目的】建立向日葵不同外植体离体培养再生体系，为向日葵遗传转化、突变体筛选奠定基础。【方法】以不同基因型向日葵为材料，研究了向日葵不同外植体在不同的培养基中诱导不定芽再生的频率。【结果】向日葵不同基因型外植体在含适宜吲哚-3-乙酸（IAA）、6-苄氨基嘌呤（6-BA）等激素的培养基中均较易形成愈伤组织，但愈伤组织诱导不定芽的能力则较弱；不同基因型向日葵外植体的不定芽诱导率依次为子叶节＞下胚轴＞子叶＞真叶；诱导子叶节不定芽再生的适宜6-BA浓度为1.2～1.8 mg•L-1， 下胚轴为1.8 mg•L-1，子叶为0.6 mg•L-1，真叶却未见到诱导出不定芽；MS + 0.03 mg•L-1 IAA + 1.2～1.5 mg•L-1 6-BA培养基可用于向日葵子叶、子叶节和下胚轴再生体系；不同基因型向日葵诱导不定芽的能力差别较大，其中，基因型PR29再生能力较强。【结论】本研究成功地建立了向日葵不同外植体离体培养再生途径，并获得了再生植株。 相似文献
3.
Park KK Liu K Hu Y Smith PD Wang C Cai B Xu B Connolly L Kramvis I Sahin M He Z 《Science (New York, N.Y.)》2008,322(5903):963-966
The failure of axons to regenerate is a major obstacle for functional recovery after central nervous system (CNS) injury. Removing extracellular inhibitory molecules results in limited axon regeneration in vivo. To test for the role of intrinsic impediments to axon regrowth, we analyzed cell growth control genes using a virus-assisted in vivo conditional knockout approach. Deletion of PTEN (phosphatase and tensin homolog), a negative regulator of the mammalian target of rapamycin (mTOR) pathway, in adult retinal ganglion cells (RGCs) promotes robust axon regeneration after optic nerve injury. In wild-type adult mice, the mTOR activity was suppressed and new protein synthesis was impaired in axotomized RGCs, which may contribute to the regeneration failure. Reactivating this pathway by conditional knockout of tuberous sclerosis complex 1, another negative regulator of the mTOR pathway, also leads to axon regeneration. Thus, our results suggest the manipulation of intrinsic growth control pathways as a therapeutic approach to promote axon regeneration after CNS injury. 相似文献
4.
The bilateral cardiac mesoderm migrates from the lateral region of the embryo to the ventral midline, where it fuses to form the primitive heart tube. It is generally accepted that migration and fusion are essential for subsequent stages of cardiac morphogenesis. We present evidence that, in Foxp4 mutant embryonic mice, each bilateral heart-forming region is capable of developing into a highly differentiated four-chambered mammalian heart in the absence of midline fusion. These data demonstrate that left-right chamber specification, cardiac looping, septation, cardiac myocyte differentiation, and endocardial cushion formation are preprogrammed in the precardiac mesoderm and do not require midline positional identity or heart tube fusion. 相似文献
5.
Lesurtel M Graf R Aleil B Walther DJ Tian Y Jochum W Gachet C Bader M Clavien PA 《Science (New York, N.Y.)》2006,312(5770):104-107
The liver can regenerate its volume after major tissue loss. In a mouse model of liver regeneration, thrombocytopenia, or impaired platelet activity resulted in the failure to initiate cellular proliferation in the liver. Platelets are major carriers of serotonin in the blood. In thrombocytopenic mice, a serotonin agonist reconstituted liver proliferation. The expression of 5-HT2A and 2B subtype serotonin receptors in the liver increased after hepatectomy. Antagonists of 5-HT2A and 2B receptors inhibited liver regeneration. Liver regeneration was also blunted in mice lacking tryptophan hydroxylase 1, which is the rate-limiting enzyme for the synthesis of peripheral serotonin. This failure of regeneration was rescued by reloading serotonin-free platelets with a serotonin precursor molecule. These results suggest that platelet-derived serotonin is involved in the initiation of liver regeneration. 相似文献
6.
以‘种都1号儿菜’(BrassicajunceaCoss.var.gemmiferaLeeetLincv.Zhong-DouNo.1)无菌子叶为材料,对看护培养效果及子叶部位对再生芽发生的影响进行了研究。结果表明,子叶可以直接分化产生再生芽。在接种子叶的同时,接种已有芽点分化的子叶外植体,可以提早再生芽的发生,并能显著提高芽再生率,但对平均再生芽数无明显影响。带子叶柄的完整子叶,其芽再生率最高,并极显著高于不带子叶柄的子叶叶片,但平均再生芽数以不带子叶柄的完整子叶叶片最高;子叶柄培养未能获得再生芽。 相似文献
7.
Nicotinic antagonists enhance process outgrowth by rat retinal ganglion cells in culture 总被引：2，自引：0，他引：2
S A Lipton M P Frosch M D Phillips D L Tauck E Aizenman 《Science (New York, N.Y.)》1988,239(4845):1293-1296
Functional nicotinic cholinergic receptors are found on mammalian retinal ganglion cell neurons in culture. The neurotransmitter acetylcholine (ACh) can be detected in the medium of many of these retinal cultures, after release presumably from the choline acetyltransferase-positive amacrine cells. The postsynaptic effect of endogenous or applied ACh on the ganglion cells can be blocked with specific nicotinic antagonists. Here it is shown that within 24 hours of producing such a pharmacologic blockade, the retinal ganglion cells begin to sprout or regenerate neuronal processes. Thus, the growth-enhancing effect of nicotinic antagonists may be due to the removal of inhibition to growth by tonic levels of ACh present in the culture medium. Since there is a spontaneous leak of ACh in the intact retina, the effects of nicotinic cholinergic drugs on process outgrowth in culture may reflect a normal control mechanism for growth or regeneration of retinal ganglion cell processes that is exerted by ACh in vivo. 相似文献
8.
9.
Nishimura H Okazaki T Tanaka Y Nakatani K Hara M Matsumori A Sasayama S Mizoguchi A Hiai H Minato N Honjo T 《Science (New York, N.Y.)》2001,291(5502):319-322
Dilated cardiomyopathy is a severe pathology of the heart with poorly understood etiology. Disruption of the gene encoding the negative immunoregulatory receptor PD-1 in BALB/c mice, but not in BALB/c RAG-2-/- mice, caused dilated cardiomyopathy with severely impaired contraction and sudden death by congestive heart failure. Affected hearts showed diffuse deposition of immunoglobulin G (IgG) on the surface of cardiomyocytes. All of the affected PD-1-/- mice exhibited high-titer circulating IgG autoantibodies reactive to a 33-kilodalton protein expressed specifically on the surface of cardiomyocytes. These results indicate that PD-1 may be an important factor contributing to the prevention of autoimmune diseases. 相似文献
10.
Immature 25-day-old mice were injected daily with 1 microgram of arginine vasotocin for 3 or 4 days and killed 24 hours after the last injection. The ovaries were 30 percent smaller in treated females than in controls. The ventral prostates and accessory organs (seminal vesicles and coagulating glands) were less than half the size of these structures in control males. Similar results were observed when 15-day-old mice were given similar injections and killed 2 weeks after the last injection; furthermore, testis weights were 28 percent smaller than those of controls. It is speculated that arginine vasotocin, which has been found in mammalian pineal glands, might mediate effects of the pineal gland on normal sexual development. 相似文献
11.
美人指葡萄再生体系的建立 总被引：1，自引：1，他引：0
以美人指葡萄为试材,研究了不同外植体类型、激素浓度配比以及暗培养时间等对器官再生的影响。结果表明:叶片、叶柄、茎段外植体均可再生出不定芽,其中叶柄的再生率最高;TDZ对美人指葡萄叶柄再生效果比6-BA好,IBA诱导美人指葡萄叶柄不定芽再生率高于NAA和2,4-D;暗培养3周时,美人指葡萄叶柄的再生率最高。叶片再生的最适培养基为:MS+1.0 mg/L TDZ+0.1 mg/L IBA,再生率为60.71%,增殖系数为5.65;叶柄再生的最适培养基为:MS+1.0mg/LTDZ+0.1 mg/L IBA,再生率为93.10%,增殖系数为5.91;茎段再生的最适培养基为:MS+1.0 mg/L TDZ+0.2 mg/L IBA,再生率为47.37%,增殖系数为5.00。将再生不定芽置于3/4 MS+0.35 mg/L IBA培养基上诱导生根,完整植株培养35~50 d后炼苗移栽,成活率可达90%。 相似文献
12.
小鼠心肌细胞的体外培养 总被引：5，自引：0，他引：5
对采用组织块法和酶消化法体外培养小鼠心肌细胞的结果进行了比较,并对体外培养心肌细胞的生理活性进行了初步测定。结果表明,用组织块法分离培养胎、乳鼠心肌可得到自主节律性搏动的心肌细胞;分别用1g/L胶原酶+10g/LBSA,0.5g/L胰酶+1g/L胶原酶,1g/L胰酶分离培养胎、乳鼠心肌,均可得到大量心肌细胞,且细胞活力较好,能自主博动20d以上;用上述2种方法分离培养成年鼠心肌,结果均不理想;在载有自主节律性搏动的小鼠心肌功能性细胞团的培养皿中加入Ca2+和肾上腺素后,细胞团搏动速度加快,搏动力加强;加入K+后则细胞团搏动速度减缓,搏动力减弱,其对钾、钙、肾上腺素的反应与在体内基本一致,表明体外培养的小鼠心肌细胞具有与在体心肌细胞相似的功能。 相似文献
13.
本研究旨在揭示斑马鱼下颌再生中神经和肌肉的关系。通过HE染色技术、免疫荧光组织化学等实验技术分别观察斑马鱼下颌神经和肌肉的再生过程,考察神经和肌肉的关系。研究结果显示,截面附近的神经纤维在剪切后5 h降解,剪切后2 d时完全消失。剪切后3 d,整个芽基所在位置已出现新生的神经纤维。剪切5 d时,芽基上布满大量的神经纤维。肌纤维在剪切后12 h已发生断裂,剪切后5 d形成芽基细胞并分化成各种前体细胞如肌肉前体细胞,剪切后9 d出现新生的肌细胞,剪切后14 d新生的肌细胞与新生的神经纤维建立神经肌肉接头联系,30 d后成为成熟的肌肉组织。结果表明:如果斑马鱼1/3的下颌被人为切除,下颌肌肉可以实现功能性再生,同时神经极可能在肌肉再生中发挥作用。但是如果切除部分超过1/3,则下颌无法再生复原,其原因有待进一步研究。 相似文献
14.
为了通过不定芽发生途径建立甜瓜‘黄蛋子’体细胞再生完整植株的技术体系,并了解掌握该品种的再生能力和再生特点,以‘黄蛋子’的幼龄子叶作为外植体,进行了组织培养条件下的再生试验。试验结果表明,在MS+6-BA2.0mg/L不定芽诱导培养基上外植体发出的再生芽(丛)为不定芽来源。58块外植体的不定芽分化频率平均为44.8%,并产生质地、数量不等的愈伤组织。在MS+6-BA0.05mg/L不定芽伸长培养基上,分化的不定芽(丛)能够伸长长大,但存在程度不同的玻璃化现象。在1/2MS+IAA0.5mg/L生根培养基上无根苗发根,生根率可达99%。与相关文献中报道过的其他甜瓜厚皮品种相比较,‘黄旦子’属再生能力弱的品种,但品种内个体之间存在再生能力上的明显差异,通过选择自交技术有可能获得再生能力得到提高的纯化株系。 相似文献
15.
以5个辣椒(Capsicum annuum L．)品种(系)为材料,针对不同基因型、苗龄、外植体种类、激 素组合等因素对辣椒植株离体再生的影响进行了较为系统的研究,从“农城椒2号”、“农城椒3号”、 “0127”、“0159”、“0171”等5个辣椒品种(系)中筛选出“农城椒2号”、“0127”、“0171”3个再生能力 较强的基因型。确定了辣椒离体再生最适外植体为子叶,最适苗龄为12-14d。筛选出高效不定芽分 化培养基(MS 3％蔗糖 0．6％琼脂 5．0mg/L BA 0．5-1．0mg/L IAA),其不定芽诱导率可达98％。诱导 出的不定芽转入MS 3％蔗糖 0．6％琼脂 3．0mg/L BA 1．0mg/L IAA 2．0mg/L GA3 10．0mg/L AgNO3 芽伸长培养基,不定芽伸长率最高可达47．1％。不定芽伸长后在MS 3％蔗糖 0．6％琼脂 0．2mg/L I- AA 0．1mg/L NAA生根培养基上诱导不定根。待其长成发达根系后移栽大田成苗,建立了辣椒高效 植株再生体系。 相似文献
16.
用手术刀片切掉仿刺参体壁表皮层和结缔组织层,深度至体腔膜。术后将仿刺参放入正常海水中饲养,用肉眼和光学显微镜观察仿刺参体壁再生的外部形态和组织学变化,并通过免疫荧光方法检测小鼠抗人角蛋白19（CK19）的表达。形态学观察表明：术后1 d,伤口呈凹陷状,体腔膜上增生出一薄层乳白色结缔组织;术后7 d伤口表面出现色素;术后11 d凹陷基本变平;术后21 d,伤口处体壁形态与颜色恢复至术前。组织学观察表明：术后1 d,疏松结缔组织直接暴露,创伤面附近有成纤维细胞和胶原纤维聚集;术后3 d,结缔组织外层有上皮细胞聚集;术后4 d,结缔组织间可见一条带状间隙;术后7 d,表皮外层出现角质层;术后11 d,上皮层厚度接近正常组织,但结缔组织较松散;术后21 d,上皮细胞数量、排列以及结缔组织的排列同正常组织。免疫荧光检测结果表明：CK19在正常的仿刺参体壁中表达得比较分散;术后3 d,CK19在创伤面附近集中表达。 相似文献
17.
Planarian flatworms can regenerate heads at anterior-facing wounds and tails at posterior-facing wounds throughout the body. How this regeneration polarity is specified has been a classic problem for more than a century. We identified a planarian gene, Smed-betacatenin-1, that controls regeneration polarity. Posterior-facing blastemas regenerate a head instead of a tail in Smed-betacatenin-1(RNAi) animals. Smed-betacatenin-1 is required after wounding and at any posterior-facing wound for polarity. Additionally, intact Smed-betacatenin-1(RNAi) animals display anteriorization during tissue turnover. Five Wnt genes and a secreted Frizzled-related Wnt antagonist-like gene are expressed in domains along the anteroposterior axis that reset to new positions during regeneration, which suggests that Wnts control polarity through Smed-betacatenin-1. Our data suggest that beta-catenin specifies the posterior character of the anteroposterior axis throughout the Bilateria and specifies regeneration polarity in planarians. 相似文献
18.
瓜叶菊'小丑'系列品种再生体系的研究 总被引：2，自引：0，他引：2
以瓜叶菊'小丑'系列5个花色品种的种子为外植体,MS为基本培养基,筛选出了瓜叶菊试管培养所需的培养基中最佳生长素种类及浓度,获得了试管苗.在此基础上,对试管苗进行了再生体系的研究.结果表明,不同外植体、生长调节剂种类及浓度均影响植株再生:叶片再生能力优于叶柄;诱导丛生芽效果最好的培养基配方为MS+6-BA 2.0 mg... 相似文献
19.
糯玉米自交系茎尖诱导再生植株研究 总被引：1，自引：1，他引：0
以2个糯玉米自交系茎尖为外植体,在添加不同浓度6-BA和2,4-D的MS培养基上诱导丛生芽和胚状体,研究糯玉米茎尖诱导丛生芽和胚状体发生的适宜条件。结果表明:经丛生芽发生途径每个茎尖可再生3~4个植株,经胚状体发生途径每个茎尖可再生9~11个植株。该结果建立了糯玉米茎尖诱导再生体系,为基因工程改良糯玉米种质奠定了基础。 相似文献
20.
D L Stocum 《Science (New York, N.Y.)》1978,200(4343):790-793
The complete circle rule of the polar coordinate model of pattern regulation was tested for regenerating hindlimbs of Ambystoma larvae. The hindlimbs were made symmetrical in the circumference of either the thigh or the shank, and their ability to regenerate from both levels was observed. Thighs composed of two anterior halves failed to regenerate, whereas thighs composed of two posterior halves often regenerated distally complete, correspondingly symmetrical limbs; shanks composed of either two anterior or two posterior halves regenerated distally complete, correspondingly symmetrical limbs. These results are in contrast to what is predicted by the complete circle rule and suggest a modification of this rule. 相似文献