滇姜花中的新二萜成分--滇姜花素D

从滇姜花Ｈｅｄｙｃｈｉｕｍｙｕｎｎａｎｅｎｓｅ根茎中分离到３个二萜成分,分别为滇姜花Ｄ（１）,圆瓣姜花素Ａ（２）和ｈｅｄｙｃｈｅｎｏｎｅ（３）,（１）为新化合物,其结构经波谱学方法鉴定为１３β－ｆｕｒａｎｏｌａｂｄａ－６－ｏｘｏ－７,１１－ｄｉｅｎ－１７－ｏｌ。     

滇姜花二萜成分的抗肿瘤活性研究

对滇姜花粗提物、滇姜花素A(1)和姜花酮(2)进行了动物体内抗肿瘤活性测试,结果表明它们均能显著性抑制小鼠体内移植性肿瘤H22的生长,其中滇姜花素A对小鼠H22肿瘤生长抑制率达54.27%,作用最强。体外抗肿瘤实验发现,滇姜花素C(3)对体外培养的人类乳腺癌细胞株MDA-MB-231具有较强的细胞毒作用,并具有明显的剂量效应关系。     

滇姜花的倍半萜成分

从滇姜花根的乙醇提取物中分离到５个倍半萜,分别是：柳杉醇（１）,α－桉醇（２）、β－桉醇（３）、β－榄醇（４）和４－Ｏ－乙基－柳杉醇（５）。其结构由光谱方法推定,其中（５）为新化合物。     

滇姜花中的两个新成分

从滇姜花(Hedychium yunnanense Gagnep.)中分离得到4个化合物,通过波谱学方法分别鉴定为cis-hedychenone(1)、isoheptand-2-O-(1→6)β-D-apiofuranosyl-β-D-glucopyranoside(2)、果糖(3)和蔗糖(4),其中1和2为新化合物.     

女贞子化学成分的研究

从女贞属植物女贞（ＬｉｇｕｓｔｒｕｍｌｕｃｉｄｕｍＡｉｔ．）的果实中分离鉴定了７个化合物,其中Ⅰ～Ⅵ系从该属植物中首次分离得到的已知化合物;化合物Ⅶ是新化合物,经光谱分析和化学定性反应确定了其结构,并命名为女贞酸。     

东川乌头中一个新的去甲二萜生物碱

从东川乌头（Aconuitum geniculatum Fletcher et Lauener)块根的乙醇提取物中分离得到3个去甲二萜生物碱,经1D,2D－NMR技术鉴定,分别为20－乙基－8－乙酰氧基－14－（对－羟基苯甲酰氧基－1α,6α,16β,18－四甲氧基乌头烷－3α,13β二醇（1）,20－乙基－8－乙酰氧基－14－苯酯基鸟头烷－3α,13β二醇（2）和20－乙基－8－乙酰氧基－14－（对－甲氧基苯酯基）乌头烷－3α,13β二醇（3）,其中1为新化合物,命名为滇羟碱（geniculine).     

东川乌头中一个新的去甲二萜生物碱( 英文)

从东川乌头 (AconitumgeniculatumFletcheretLauener)块根的乙醇提取物中分离得到 3个去甲二萜生物碱 ,经 1D、 2D -NMR技术鉴定 ,分别为 2 0 -乙基 - 8-乙酰氧基 - 14- (对 -羟基苯甲酰氧基 ) - 1α ,6α ,16 β ,18-四甲氧基乌头烷 - 3α ,13β二醇 (1)、 2 0 -乙基 - 8-乙酰氧基 - 14-苯酯基乌头烷 - 3α ,13β二醇 (2 )和 2 0 -乙基 - 8-乙酰氧基 - 14- (对 -甲氧基苯酯基 )乌头烷 - 3α ,13β二醇 (3) ,其中 1为新化合物 ,命名为滇羟碱 (geniculine)。     

毛萼香茶菜中的新二萜化合物——毛萼晶P

从毛萼香茶菜的叶的甲醇提取物中分离得到两个二萜化合物,ｃｏｅｔｓｏｉｄｉｎＡ和毛萼晶Ｐ,它是目前从香茶菜属分离到的仅有的两个Ｂ环具有α,β－不饱和酮结构的对映－贝壳杉烷型二萜事物,其中毛萼晶Ｐ为新化合物     

鹿衔草化学成分的研究：羟基肾叶鹿蹄草甙的结构鉴定

从鹿衔草（Ｐｙｒｏｌａ ｃａｌｌｉａｎｔｈａ Ｈ．Ａｎｄｒｅｓ）分离得到两个化合物。经光谱分析,确定其中１个化合物为新化合物,命名为羟基肾叶鹿蹄草甙（１, ｈｙｄｒｏｘｙｌｒｅｎｉｆｏｌｉｎ）,另一化合物为儿茶素（３）。     

冬凌草中一个苯丙醇酯新化合物

通过多种色谱手段,从冬凌草95％乙醇提取物中分离得到一个新化合物。运用多种波谱技术（1D、2D—NMR和MS）,该新化合物鉴定为2-氨基-3-苯丙基2-苯甲酰氨基-3-利胆醇酯（苯丙醇酯）。     

滇姜花中的新二萜成分-滇姜花戊素

从滇姜花根茎中分离到１个新二萜成分,命名为滇姜花戊素（１）,其结构经波谱学方法鉴定为１３β－ｆｕｒａｎｏｌａｂｄａ－８（１７）,１１－ｄｉｅｎ－６β,７α－ｄｉｏｌ。     

Separation of rat lactate dehydrogenase isoenzyme C4 from other isoenzymes by affinity and ion-exchange chromatography.

Lactate dehydrogenase C, an isoenzyme composed of C polypeptide subunits and found only in mature testes and spermatozoa, differs kinetically, chemically and immunologically from the five common isoenzymes of lactate dehydrogenase, each of which is a tetramer of A and/or B subunits. In the rat lactate dehydrogenase C exists in two molecular forms, isoenzymes C4 and A1C3. In addition to these two forms of lactate dehydrogenase C, rat testicular homogenate contains all the five isoenzymes of A and B type. Purification of isoenzyme C4 requires its separation from the other six isoenzymes, of which isoenzymes A1C3 and A3B1 are the most difficult ones to separate. In the present study isoenzyme A3B1, along with other enzymes, was separated from isoenzyme C4 by AMP-Sepharose chromatography by using a gradient of increasing concentration of NAD+-pyruvate adduct. In the next step, isoenzyme A1C3 was separated from isoenzyme C4 by DEAD-cellulose chromatography, resulting in a pure lactate dehydrogenase isoenzyme C4 preparation.     

Restriction fragment analysis of duplication of the fourth component of complement (C4A)

The two genes encoding the fourth component of complement (C4A and C4B) reside between HLA-B and HLA-DR on human chromosome 6. Two kilobases downstream from each C4 gene lies a 21-hydroxylase gene (CA21HA and CA21HB, respectively). Utilizing the method of Southern blotting and a 5'-end 2.4-kb BamHI/KpnI fragment of the C4 cDNA, we have analyzed TaqI-digested DNA from four pedigrees with one or more extended haplotypes containing a C4A duplication, as demonstrated by protein electrophoresis and segregation analysis. Two C4A protein duplications (C4A*2,A*3,C4B*QO and C4A*3,A*5,C4B*QO) segregated with two large TaqI DNA restriction fragments (7.0 and 6.0). In pedigree Fi, one individual homozygous for HLA-A3,B35,C4,DR1,DQ1,BFF,C2C,-C4A2,3,C4BQO had TaqI 7.0- and 6.0-kb restriction fragments with equal hybridization intensities as measured by two-dimensional densitometry (7.0/6.0 kb = 0.83, SD = 0.12, N = 7). A hybridization probe for the 21-hydroxylase gene also demonstrated equal gene dosage (CA21HA/CA21HB = 1.01). DNA from another individual (Ma I-2) with a different C4A gene duplication (C4A*3,A*5,C4B*QO) also had equal densitometry measurements (7.0/6.0 kb = 1.07). We conclude that two extended haplotypes from unrelated pedigrees have two C4 genes and both C4 genes encode separate C4A alleles. These findings are compatible with a gene conversion event of C4B to C4A.     

The structural basis of the multiple forms of human complement component C4

cDNA clones of human complement components C4A and C4B alleles were prepared from mRNA obtained from the liver of a donor heterozygous at both loci. cDNA from one C4A allele was sequenced to give the derived complete amino acid sequence of 1722 amino acid residues of the C4 single chain precursor molecule and the estimated sequences of the three peptide chains of secreted C4. Comparison with partial sequences of a second C4A allele and a C4B allele has led to the tentative identification of some class differences in nucleotide sequences between C4A and C4B and of allelic differences between C4A alleles in this highly polymorphic system.     

The low C5 convertase activity of the C4A6 allotype of human complement component C4.

We have compared the C5-convertase-forming ability of different C4 allotypes, including the C4A6 allotype, which has low haemolytic activity and which has previously been shown to be defective in C5-convertase formation. Recent studies suggest that C4 plays two roles in the formation of the C5 convertase from the C3 convertase. Firstly, C4b acts as the binding site for C3 which, upon cleavage by C2, forms a covalent linkage with the C4b. Secondly, C4b with covalently attached C3b serves to form a high-affinity binding site for C5. Purified allotypes C4A3, C4B1 and C4A6 were used to compare these two activities of C4. Covalently linked C4b-C3b complexes were formed on sheep erythrocytes with similar efficiency by using C4A3 and C4B1, indicating that the two isotypes behave similarly as acceptors for covalent attachment of C3b. C4A6 showed normal efficiency in this function. However, cells bearing C4b-C3b complexes made from C4A6 contained only a small number of high-affinity binding sites for C5. Therefore a lack of binding of C5 to the C4b C3b complexes is the reason for the inefficient formation of C5 convertase by C4A6. The small number of high-affinity binding sites created, when C4A6 was used, were tested for inhibition by anti-C3 and anti-C4. Anti-C4 did not inhibit C5 binding, whereas anti-C3 did. This suggests that the sites created when C4A6 is used to make C3 convertase may be C3b-C3b dimers, and hence the low haemolytic activity of C4A6 results from the creation of low numbers of alternative-pathway C5-convertase sites.     

Amphibian pepsinogens: purification and characterization of xenopus pepsinogens, and molecular cloning of Xenopus and bullfrog pepsinogens

Two pepsinogens (Pg C and Pg A) were isolated from the stomach of adult Xenopus laevis by Q-Sepharose, Sephadex G-75, and Mono-Q column chromatographies. Autolytic conversion and activation of the purified Pgs into the pepsins were examined by acid treatment. We determined the amino acid sequences from the NH2-termini of Pg C, pepsin C, Pg A, and pepsin A. Based on the sequences, the cDNAs for Pg C and Pg A were cloned from adult stomach RNA, and the complete amino acid sequences of the Pg C and Pg A were predicted. In addition, a Pg A cDNA was cloned from the stomach of adult bullfrog Rana catesbeiana, and the primary structure of the Pg A was predicted. Molecular phylogenetic analysis showed that such anuran Pg C and Pg A belong to the Pg C group and the Pg A group in vertebrates, respectively. The molecular properties of Pg C and Pg A, such as size, sequences of the activation peptide and active site, profile of autolytic activation, and pH dependency of proteolytic activity of the activated forms, pepsin C and pepsin A, resemble those of Pgs found in other vertebrates. However, the hemoglobin-hydrolyzing activity of Xenopus pepsin C is completely inhibited in the presence of equimolar pepstatin, an inhibitor of aspartic proteinases. Thus, the Xenopus pepsin C differs significantly from other vertebrate pepsins C in its high susceptibility to pepstatin, and closely resembles A-type pepsins.     

Isolation and characterization of phosphofructokinase C from rabbit brain

Phosphofructokinase from rabbit brain consists of hybrids of the A, B, and C isozymes. Phosphofructokinase C was isolated from a purified mixture of such hybrids in a 2-step procedure. In the first step, phosphofructokinase B was removed by chromatography on DEAE-Sephadex. In the second step, subunits of phosphofructokinases A and C were separated by dissociation at pH 5.0 followed by chromatography on carboxymethylcellulose. The separated isozymes were then reassociated by neutralization. Phosphofructokinase C was structurally distinct from phosphofructokinases A (obtained from muscle or brain) and B (obtained from liver) as shown by one-dimensional chymotryptic and staphylococcal V8 protease fingerprints of all three isozymes. In addition, phosphofructokinase C cross-reacted weakly or not at all with antisera raised against phosphofructokinase B or phosphofructokinase A. Phosphofructokinase C was also kinetically distinct from the A and B isozymes. The C isozyme was more sensitive than the A isozyme but less sensitive than the B isozyme to inhibition by ATP, was less sensitive than the A isozyme but more sensitive than the B isozyme to inhibition by citrate, and was less sensitive than either of the other two isozymes to activation by inorganic phosphate, AMP, and fructose 2,6-bisphosphate. The self-association properties of phosphofructokinase C differed from those of the A and B isozymes in that at pH 8.0, the C isozyme did not form oligomers larger than a tetramer under conditions where the other two isozymes did. Thus the properties of phosphofructokinase C are in general quite distinct from those of the other two phosphofructokinase isozymes.     

Nucleotide sequence of Scenedesmus obliquus cytoplasmic initiator tRNA.

The cytoplasmic initiator tRNA from the green alga Scenedesmus obliquus has been purified and its sequence shown to be p A G C U G A G-U m G m G C G C A G D G G A A G C G psi m G A psi G G G C U C A U t A A--C C C A U A G m G D m C A C A G G A U C G m A A A C C U Gm U C U C A--G C U A C C A-O H. The sequence has been deduced and confirmed using several different P-post labelling techniques. The sequence is similar to those of other eukaryotic cytoplasmic initiator tRNAs and it has the sequence G A U C in place of the usual G T psi C. Although it resembles lower eukaryotic species in having a U preceding the anticodon and a modified G in the T psi C stem, in overall homology it is closer to the higher eukaryotic than to the fungal initiator tRNAs.