可乐茄叶肉原生质体培养再生植株

本文报道茄属果树可乐茄（ＳｏｌａｎｕｍｑｕｉｔｏｅｎｓｅＬａｍ．）叶肉原生质体的分离、培养及植株再生。幼嫩叶片原生质体经酶游离、纯化后,以１×１０４个／ｍｌ密度培养于稍加改良Ｋ８ｐ（附加２,４－Ｄ０．５ｍｇＬ（－１）、ＮＡＡ１．０ｍｇＬ（－１）和ＢＡ０．５ｍｇＬ（－１））的培养基中,三天后开始分裂,一周分裂３—４次。一个月形成小细胞团,植板率为０．１—０．２％,小细胞团转培养于ＭＳ＋２,４－Ｄ０．５ｍｇＬ（－１）上增殖后进行分化。原生质体来源愈伤组织在ＩＡＡ（０．１—１．０ｍｇＬ（－１））与ＢＡ或ＺＴ组合的培养基中能诱导器官发生,芽分化率最高可达４２．９％;但ＩＡＡ、ＢＡ、ＺＴ三者一起使用未见任何器官分化。小芽在ＭＳ＋ＩＡＡ０．２ｍｇＬ（－１）中生根成植株。可乐茄叶肉原生质体的植株再生,可应用于育种和茄属植物遗传工程研究。     

人粒细胞集落刺激因子（hG－CSF）cDNA3′－UTR对其表达的影响

利用人粒细胞集落刺激因子（ｈＧ－ＣＳＦ）ｃＤＮＡ３′端非翻译区（３′－ＵＴＲ）中存在的ＤｒａⅠ酶切位点,通过部分酶切与完全酶切,删除３′－ＵＴＲ不同长度,构建了四种ｈＧ－ＣＳＦｃＤＮＡ瞬时重组表达质粒。转染ＣＯＳ－７细胞后,生物活性测定结果提示,ｈＧ－ＣＳＦｃＤＮＡ３′－ＵＴＲ对其表达起负调控作用,其关键性序列位于紧接终止密码子ＴＧＡ下游的６５ｂｐ范围内,３′－ＵＴＲ对ｈＧ－ＣＳＦｃＤＮＡ表达的影响与转录水平的差别有一定关系。     

大瓶螺碱性磷酸酶的分离纯化及部分性质研究

大瓶螺碱性磷酸酶的分离纯化及部分性质研究李清漪,曾和期（西南师范大学生物系,重庆６３０７１５）碱性磷酸酶（ＥＣ３．１．３．１,简称ＡＫＰ）是广泛存在于动物组织中的水解酶。对软体动物中ＡＫＰ的研究仅有少数报道［１,２］,对属于单壳贝类的水生食用螺──大...     

人鼻咽癌细胞基因组中瘤基因Ha－ras－1的Dnase Ⅰ超敏感位点的初步研究

ＤＮａｓｅⅠ超敏感位点的研究能够发现潜在的调控基因转录活化的位点,比较正常人外周血有核细胞,淋巴瘤细胞株Ｐ３ＨＲ１和人鼻咽癌低分化磷癌细胞株ＨＯｎＥ１和ＨＮＥ２中Ｈａ－ｒａｓ－１瘤基因的ＤＮａｓｅⅠ超敏感位点发现,只有ＨＯＮＥ１和ＨＮＥ２细胞基因组中存在一个ＤＮａｓｅⅠ超敏感位点,位于第一个外显子上游０．３７ｋｂ处,上述结果提示正常白细胞和Ｐ３ＨＲ１细胞中Ｈａ－ｒａｓ－１基因处于失活状态,而在鼻咽癌细胞基因组中则处于活化状态,它的活化可能与０．３７ｋｂ处的ＤＮＡ序列有密切的关系。     

Oxytocin induced a biphasic increase in the intracellular Ca2+ concentration of porcine myometrial cells: Participation of a pertussis toxin—insensitive G-protein,inositol 1,4,5-trisphosphate—sensitive Ca2+ pool,and Ca2+ channels

This study investigated the underlying mechanisms of oxytocin (OT)-induced increases in intracellular Ca²⁺ concentrations ([Ca²⁺]_i) in acutely dispersed myometrial cells from prepartum sows. A dosedependent increase in [Ca²⁺]_i was induced by OT (0.1 nM to 1 μM) in the presence and absence of extracellular Ca²⁺ ([Ca²⁺]_e). [Ca²⁺]_i was elevated by OT in a biphasic pattern, with a spike followed by a sustained plateau in the presence of [Ca²⁺]_e. However, in the absence of [Ca²⁺]_e, the [Ca²⁺]_i response to OT became monophasic with a lower amplitude and no plateau, and this monophasic increase was abolished by pretreatment with ionomycin, a Ca²⁺ ionophore. Administration of OT (1 μM) for 15 sec increased inositol 1,4,5-trisphosphate (IP₃) formation by 61%. Pretreatment with pertussis toxin (PTX, 1 μg/ml) for 2 hr failed to alter the OT-induced increase in [Ca²⁺]_i and IP₃ formation. U-73122 (30 nM to 3 μM), a phospholipase C (PLC) inhibitor, depressed the rise in [Ca²⁺]_i by OT dose dependently. U-73122 (3 μM) also abolished the OT-induced IP₃ formation. Thapsigargin (2 μM), an inhibitor of Ca²⁺-ATPase in the endoplasmic reticulum, did not increase [Ca²⁺]_i. However, it did time-dependently inhibit the OT-induced increase in [Ca²⁺]_i. Nimodipine (1 μM), a Voltage-dependent Ca²⁺ channel (VDCC) blocker, inhibited the OT-induced plateau by 26%. La³⁺ (1 μM), a nonspecific Ca²⁺ channel blocker, abrogated the OT-induced plateau. In whole-cell patch-clamp studies used to evaluate VDCC activities, OT (0.1 μM) increased Ca²⁺ Current (I_ca) by 40% with no apparent changes in the current-voltage relationship. The OT-induced increase in I_ca reached the maximum in 5 min, and the increase was abolished by nimodipine (1 μM). These results suggested that (1) activation of OT receptors in porcine myometrium evokes a cascade in the PTX-insensitive G-protein–PLC-IP₃ signal transduction, resulting in an increase in [Ca²⁺]_i; (2) the OT-induced increase in [Ca²⁺]_i is characterized by a biphasic pattern, in which the spike is predominately contributed by the intracellular Ca²⁺ release from the IP₃-sensitive pool, and to a lesser extent by Ca²⁺ influx, whereas the plateau is from increased Ca²⁺ influx; and (3) the influx is via VDCC and receptor-operated Ca²⁺ channels. © 1995 Wiley-Liss, Inc.     

Nitric oxide synthase in the enteric nervous system of the guinea-pig: a quantitative description

The distribution and abundance of nitric oxide synthase (NOS)-containing neurons and their terminals in the gastrointestinal tract of the guinea-pig were examined in detail using NADPH diaphorase histochemistry and NOS immunohistochemistry. NOS-containing cell bodies were found in the myenteric plexus throughout the gastrointestinal tract and in the submucous plexus of the stomach, colon and rectum. NOS-containing neurons comprised between 12% (in the duodenum) and 54% (in the esophagus) of total myenteric neurons. In the ileum, NOS neurons represented 19% of total myenteric neurons. Most of the NOS neurons throughout the gastrointestinal tract possessed lamellar dendrites and a single axon. NOS-containing terminals were abundant in the circular muscle, including that of the sphincters, but were rare in the longitudinal muscle, except for the taeniae of the caecum. The muscularis mucosae of the esophagus, stomach, colon and rectum received a medium to dense innervation by NOS terminals. Within myenteric ganglia, NOS-containing terminals were extremely sparse in the esophagus, stomach and duodenum, common in the ileum and distal colon and extremely dense in the proximal colon and rectum. The submucous plexus in the ileum and large intestine contained a sparse plexus of NOS-containing terminals. NOS terminals were not observed in the mucosa of any region. We conclude that throughout the gastrointestinal tract of the guinea-pig, NOS neurons are inhibitory motor neurons to the circular muscle; in the ileum and large intestine, NOS neurons may also function as interneurons.