中国鸡皮衣属地衣化学成分研究

作者通过对隶属于３５个分类单位的近４００号中国鸡皮衣属地衣标本的化学测定,在本文中报道了我国鸡皮衣属地衣中存在的２３个化合物,首次报道鸡皮衣属地衣中存在的有分类意义的化学成分１种,即ｍａｌｏｎｏｐｒｏｔｏｃｅｔｒａｒｉｃａｃｉｄ。化学测定结果表明：至少在中国鸡皮衣属种中,４,５－二氯地衣酮（４,５－ｄｉｃｈｌｏｒｏｌｉｃｈｅｘａｎｔｈｏｎｅ）可能局限于Ｐｅｒｔｕｓａｒｉａ亚属;β－地衣酚类（β－ｏｒｃｉｎｏｌ）化合物是主导的髓层化学成分;β－地衣酚类缩酚酸（β－ｏｒｅｉｎｏｌｄｅｐｓｉｄｅｓ）和β－地衣酚类原岛衣酸型缩酚酸环醚（β－ｏｒｃｉｎｏｌｐｒｏｔｏｃｅｔｒａｒｉｃａcｉｄ－ｔｙｐｅｄｅｐｓｉｄｏｎｅｓ）是Ｐｉｏｎｏｓｐｏｒａ亚属的特征性化学成分,β－地衣酚类斑点酸型缩酚酸环醚（β－ｏｒｃｉｎｏｌｓｔｉｃｔｉｃ　ａｃｉｄ－ｔｙｐｅｄｅｐｓｉｄｏｎｅｓ）是Ｐｅｒｔｕｓａｒｉａ亚属的特征化学成分。形态和化学特征在鸡皮衣属内存在着平行的或独立的进化路线。     

藻红蓝蛋白α-亚基脱辅基蛋白与藻蓝胆素的重组

利用在大肠杆菌中表达的藻红蓝蛋白α－亚基脱辅基蛋白与藻蓝胆素PCB重组,吸收光谱、荧光光谱和高效可逆光化学性质分析表明,藻红蓝蛋白α－亚基脱辅基蛋白与藻蓝胆素直接重组,生成的胆素蛋白中辅基色素仍为藻蓝胆素;而藻红蓝蛋白α-亚基脱辅基蛋白与藻蓝胆素在藻红蓝蛋白α－亚基重组酶（pecE和pecF基因的表达产物）催化下重组,生成的胆素蛋白中辅基色素转变为藻紫胆素,并具有高效可逆光化学特性。     

乙酰乳酸合成酶的制备、分离与纯化

乙酰乳酸合成酶［１］（ａｃｅｔｏｌａｃｔａｔｅｓｙｎｔｈａｓｅ,ＡＬＳ）是目前国际上除草剂研究的前沿热点．它能催化一分子丙酮酸脱羧并与另一分子丙酮酸缩合成一分子乙酰乳酸,从而导致侧链氨基酸缬氨酸、亮氨酸和异亮氨酸的生物合成．存在于细菌和植物组织中［２...     

中国禾草三新种

报道了禾本科鹅观草属二新种和以礼草属一新种,即稀节鹅观草（Ｒｏｅｇｎｅｒｉａｌａｘｉｎｏｄｉｓ）,缩芒鹅观草（Ｒｏｅｇｎｅｒｉａｃｕｒｔｉａｒｉｓｔａｔａ）和沙湾以礼草（Ｋｅｎｇｙｉｌｉａｓｈａｗａｎｅｎｓｉｓ）．     

温度,pH和后熟处理对缩球囊霉孢子萌发的影响

研究了温度、ｐＨ和后熟处理对缩球囊霉（Ｇｌｏｍｕｓ　ｃｏｎｓｔｒｉｃｔｕｍ Ｔｒａｐｐｅ）孢子萌发的影响,结果发现从云南热带植物河口观音座莲（Ａｎｇｉｏｐｔｅｒｉｓ ｈｏｋｏｕｅｎｓｉｓ, Ｃｈｉｎｇ）根际土壤中采集的缩球囊霉孢子萌发的最适温度在２５℃～３０℃之间,最适ｐＨ在５～６之间,后熟处理明显能提高缩球囊霉孢子的萌发率;同时还观察到缩球囊霉孢子萌发时只产生一根芽管;缩球囊霉孢子的萌发率较其他一些ＶＡ菌根真菌孢子的萌发率低,不同季节采集到的孢子其萌发率有明显的差异。     

温度、pH和后熟处理对缩球囊霉孢子萌发的影响*

研究了温度、ｐＨ和后熟处理对缩球囊霉（Ｇｌｏｍｕｓ　ｃｏｎｓｔｒｉｃｔｕｍ Ｔｒａｐｐｅ）孢子萌发的影响,结果发现从云南热带植物河口观音座莲（Ａｎｇｉｏｐｔｅｒｉｓ ｈｏｋｏｕｅｎｓｉｓ, Ｃｈｉｎｇ）根际土壤中采集的缩球囊霉孢子萌发的最适温度在２５℃～３０℃之间,最适ｐＨ在５～６之间,后熟处理明显能提高缩球囊霉孢子的萌发率;同时还观察到缩球囊霉孢子萌发时只产生一根芽管;缩球囊霉孢子的萌发率较其他一些ＶＡ菌根真菌孢子的萌发率低,不同季节采集到的孢子其萌发率有明显的差异。     

彗星电泳法在植物原生质体凋亡检测中的应用

应用中性法彗星电泳检测烟草（ＮｉｃｏｔｉａｎａｔａｂａｃｕｍＬ．）原生质体的凋亡。结果表明,彗星发生的百分率（彗星率）和发生核质固缩及“核着边”（凋亡形态学标志）的细胞的百分率之间存在明确的相关性。利用标准的细胞凋亡检测手段,包括ＤＮＡｌａｄｄｅｒｉｎｇ及核糖核酸末端转移酶介导的ｂｉｏｔｉｎｄＵＴＰ缺口末端标记（ＴＵＮＥＬ）,都证明这种彗星电泳法可以用来比较精确地检测植物原生质体的凋亡。     

相山虫草──蝉草

相山虫草──蝉草王光,朱学玲（安徽省淮北矿务局岱河矿中学２３５０３７）蝉草是由一种子囊菌纲（Ａｓｃｏｍｐｃｅｔｅｓ）、肉座目（Ｈｙｐｃｏｒｅａｌｅｓ）、虫草属（ｏｏｒｄｙｃｅｐｓ）的真菌寄生于同翅目（Ｈｏｍｏｐｔｅｒａ）、蝉科（Ｃｉｃａｄｉｄａｅ）、...     

长白山珍稀植物－草苁蓉

长白山珍稀植物－草苁蓉于英赵淑春修荆昌（吉林农业大学野植教研室,长春１３０１１８）（吉林省园艺特产管理站）长白山珍稀野生植物草苁蓉（ＢｏｓｃｈｎｉａｋｉａｒｏｓｓｉｃａＦｅｄｔｓｃｈｅｔＦｌｅｒｏｖ）,系列当科（Ｏｒｏｂａｎ－ｃｈａｃｅａｅ）植物,俗...     

中国齿裂菌属研究Ⅰ

具裂菌属（Ｃｏｃｃｏｍｙｃｅｓ）二新种,生于映山红（Ｒｈｏｄｏｄｅｎｄｒｏｎ ｓｉｍｓｉｉ）上的卷丝齿裂菌（Ｃ．ｃｉｒｃｉｎａｔｕｓ）和生于乌榄（Ｃａｎａｒｉｕｍ ｐｉｍｅｌａ）上的杯状齿裂菌（Ｃ．ｃｒａｔｅｒｉｆｏｒｍｉｓ）。新种有拉丁文、中文描述和图解,并讨论。模式标本收藏于安徽农业大学森林保护教研室（ＡＡＵＦＰ）。     

大鼠脑谷氨酸脱羧酶基因的cDNA克隆及序列分析

胰岛β－细胞自身抗原蛋白之一是脑中谷氨酸脱羧酶（Ｇｌｕｔａｍｉｃａｃｉｄｄｅｃａｒｂｏｘｙｌａｓｅ,ＧＡＤ,ＥＣ４．１．１．１５）同源物。以双链ｃＤＮＡ为模板,用ＰＣＲ方法快速克隆了Ｗｉｓｔａｒ大鼠脑ＧＡＤ基因的ｃＤＮＡ,将此包括编码５９３个氨基酸的全长ＤＮＡ片段重组入ｐＵＣ质粒并用双脱氧末端终止法测定了全部序列,证明其全长为１７７９ｂｐ．经比较发现Ｗｉｓｔａｒ大鼠脑与Ｒｕｓｓｅｌｌ报导的大鼠脑ＧＡＤ基因序列,有一处碱基的差别,但并不涉及氨基酸的改变。同时还对用ＰＣＲ扩增长片段ＤＮＡ进行了方法学上的探讨。     

Measurement of mRNA specific for preprocholecystokinin in rat caudatoputamen and areas projecting to it

The concentrations of mRNA specific for preprocholecystokinin were measured with a hybridisation procedure after its extraction from rat brain samples. mRNA specific for preprocholecystokinin was not consistently found in the caudatoputamen. In contrast, its concentrations were quite high in the cingulate, subcallosal and parietal cortical areas, which are assumed to send cholecystokinin-containing axons to the caudatoputamen. Also in other areas in which cholecystokinin-pathways to the caudatoputamen may originate, such as the amygdaloid complex, the piriform cortex and the ventral tegmental area/substantia nigra, mRNA specific for preprocholecystokinin could be demonstrated. It is concluded that the caudatoputamen contains no or very few perikarya which synthetize cholecystokinin and that cholecystokinin-peptides which are found in high concentrations in this part of the basal ganglia are located in afferents.     

Chemical characterization of rat cholecystokinin-58

Cholecystokinin-58 (CCK-58) was purified from rat intestines using an extraction method that yields large amounts of this peptide. Greater than 30% of total CCK immunoreactivity eluted before CCK-39 upon gel permeation chromatography (Sephadex G-50) if extracts were loaded onto Sep Pak cartridges before freezing. If the extracts were frozen and stored at −70°C for six weeks, only 20% of the material eluted in this region and total immunoreactivity was reduced by 50%, suggesting that proteases were active under these storage conditions. This early eluting peak was purified by reverse phase and ion-exchange HPLC to a single absorbance peak. Microsequence analysis of this peak detected AVLRPDSEP which is the amino terminus of rat CCK-58 predicted from the rat preprocholecystokinin cDNA. Because degradation of CCK-58 occurred in these extracts, it is possible that CCK-58 is the predominant molecule form in the rat small intestine.     

In situ localization with digoxigenin-labelled probes of tau-related mRNAs in the rat pancreas

Summary Two cDNA probes complementary to fetal rat brain tau cDNA were produced by the polymerase chain reaction (PCR) and labelled by digoxigenin-11-dUTP incorporation during the PCR elongation step. These probes were tested for thein situ localization of tau mRNAs in sections of rat cerebellum. The hybridization signal was consistent with the known localization of brain tau mRNAs, showing the validity of cDNA probes labelled by digoxigenin during the PCR. Using these probes, anin situ hybridization protocol was established and optimized for the localization of tau-related mRNAs in sections of pancreas. The aim was to determine whether these mRNAs were expressed in the exocrine or the endocrine part of the pancreas. A positive signal was found only in the exocrine part of the pancreas, and was distributed exclusively in the cytoplasm of acinar cells. The results described here are the first evidence for a specific expression of tau-related proteins in the exocrine pancreas.     

Localization of brain nitric oxide synthase (NOS) to human chromosome 12.

Recent research has shown that nitric oxide is a novel neuronal second messenger and transmitter that may be involved in neuronal cell death and damage in neurological illness. To map the chromosomal localization of this important brain enzyme, a rat cDNA probe was prepared by RNA PCR from rat cerebellum RNA. This rat cDNA was used to isolate a human nitric oxide synthase (NOS) cDNA from a human cerebellum cDNA library. The human cDNA clone containing 1.2 kb of brain NOS cDNA was hybridized to Southern blots containing DNAs obtained from human-rodent hybrid cell line panels using EcoRI and HindIII digestion to ascertain the location of the human NOS gene. These data showed that the human brain nitric oxide synthase mapped within 12q14-qter on human chromosome 12.     

Isolation, structure and properties of the C-terminal flanking peptide of preprocholecystokinin from rat brain

The C-terminal flanking peptide of preprocholecystokinin has been isolated from rat brain. Micro-sequence analysis revealed the primary structure: Ser-Ala-Glu-Asp-Tyr-Glu-Tyr-Pro-Ser. Arylsulphatase and mild acid hydrolysis suggested that both tyrosine residues are sulphated. The peptide was not active in bioassay systems that respond to CCK8; the significance of the conserved tripeptide Ser-Ala-Glu is discussed.     

New molecular forms of cholecystokinin. Microsequence analysis of forms previously characterized by chromatographic methods

Cholecystokinin previously has been characterized by chromatographic and immunological techniques. Analysis of cDNA has revealed the structure of preprocholecystokinin. The predicted processing sites of preprocholecystokinin cannot account for the multiple forms of cholecystokinin detected. This report details the isolation and characterization of cholecystokinin peptides containing 58, 39, 33, 25, 18, 8, 7, and 5 amino acids. None of the cleavages that occurred to form these peptides was at the carboxyl side of double basic residues. Cholecystokinin 25, 18, and 7 have not previously been isolated and identified by sequence analysis. The processing that forms these peptides includes cleavage after single basic residues for the 58, 39, 33, and 8 amino acid peptides. The 25, 18, 7, and 5 amino acid peptides must be formed by other endopeptidases or combinations of endo- and exopeptidases. The analysis of this series of peptides provides the chemical basis for structural differences in cholecystokinin molecules previously demonstrated by chromatographic and immunological methods. These structures provide insight into tissue-specific processing that occurs for this important regulatory peptide in intestine and brain.     

A polymerase chain reaction strategy to identify and clone cyclic nucleotide phosphodiesterase cDNAs. Molecular cloning of the cDNA encoding the 63-kDa calmodulin-dependent phosphodiesterase.

Multiple isozymes of cyclic nucleotide phosphodiesterases (PDEs) are expressed simultaneously in mammalian tissues. To identify and clone these PDEs, a polymerase chain reaction (PCR) strategy was developed using degenerate oligonucleotide primers designed to hybridize with highly conserved PDE DNA domains. Both known and novel PDEs were cloned from rat liver, the mouse K30a-3.3 lymphoma cell line, and a human hypothalamus cDNA library, demonstrating that these PCR primers can be used to amplify the cDNA of multiple PDE isozymes. One unique mouse PDE clone was found to encode a polypeptide identical with the corresponding portion of the bovine brain 63-kDa calmodulin-dependent PDE as reported in the companion article (Bentley, J. K., Kadlecek, A., Sherbert, C. H., Seger, D., Sonnenburg, W. K., Charbonneau, H., Novack, J. P., and Beavo, J. A. (1992) J. Biol. Chem. 267, 18676-18682). This mouse clone was used as a probe to screen a rat brain cDNA library for a full-length clone. The conceptual translation of the nucleotide sequence of the resulting rat clone has an open reading frame of 535 amino acids and maintains a high degree of homology with the bovine 63-kDa calmodulin-dependent PDE, indicating that this protein is likely to be the rat homolog of the 63-kDa calmodulin-dependent PDE. Expression of the full-length clone in Escherichia coli yielded a cGMP hydrolyzing activity that was stimulated severalfold by calmodulin. Northern blot analysis demonstrated that the mRNA encoding this PDE is highly expressed in rat brain and also in the S49.1 T-lymphocyte cell line. These data demonstrate that the PCR method described is a viable strategy to isolate cDNA clones of known and novel members of different families of PDE isozymes. Molecular cloning of these PDEs will provide valuable tools for investigating the roles of these isozymes in regulation of intracellular concentrations of the cyclic nucleotides.     

Cloning and Characterization of a Soluble Kynurenine Aminotransferase from Rat Brain: Identity with Kidney Cysteine Conjugate β-Lyase

Abstract: In this study, we describe the cloning and characterization of a soluble form of kynurenine aminotransferase (KAT, EC 2.6.1.7) present in rat brain. Soluble KAT was purified from rat kidney and the amino acid sequences of four tryptic peptides determined. These peptides were found to belong to the amino acid sequence reported for rat kidney soluble cysteine conjugate β-lyase, indicating that rat kidney KAT and β-lyase represent the same molecular entity. Oligonucleotide probes derived from the β-lyase cDNA were then used as primers for PCR of reverse-transcribed rat brain poly(A)⁺ RNA. After subcloning of the resulting PCR fragment and sequencing of the isolated rat brain clone, its oligonucleotide sequence was found to be identical to that reported for the β-lyase cDNA. Further evidence that the isolated rat brain clone encoded for KAT was obtained by transfecting HEK-293 cells with a construct containing the coding sequence for the enzyme. The transfected cells exhibited KAT activity and, in the presence of 2 m M pyruvate and 2-oxoglutarate, the K _m values for l -kynurenine were 1.2 m M and 86.3 µ M , respectively. Northern blot analysis of rat kidney, liver, and brain RNA revealed a single species of KAT/β-lyase mRNA of ∼2.1 kb.