小水榕的组织培养与快速繁殖

1植物名称小水榕(anubias barteri). 2材料类别茎尖、茎段. 3培养条件诱导培养基:(1)MS 6-BA 5.0 mg·L-1(单位下同) KT 5.0;增殖培养基:(2)MS 6-BA1.0,(3)MS 6-BA 2.0,(4)MS 6-BA 3.0,(5)MS 6-BA 4.0,(6)MS 6-BA 5.0;生根培养基:(7)MS NAA 0.3 IBA 0.2.各培养基中均添加20 g·L-1白糖、5 g·L-1琼脂,pH 5.8.培养温度25～30℃,诱导和增殖培养的光照度500 lx,生根培养的光照度1 500～2 000 lx,光照时间12 h·d-1.     

芋螺毒素研究进展

芋螺毒素是７０年代末期发现的一类海洋生物神经毒肽,近２０年来研究进展十分迅速,其独特的化学结构特征,高选择性的生物活性,协同性的作用机制,以及其生态作用等都引起了广泛注意,成为生命科学研究中的一个新的活跃领域,在多肽化学,分子生物学以及新药研究等方面都有十分诱人的发展前景,本文就这方面研究进行了综述。     

A common African polymorphism abolishes tyrosine sulfation of human anionic trypsinogen (PRSS2)

Human pancreatic trypsinogens undergo post-translational sulfation on Tyr(154), catalysed by the Golgi-resident enzyme tyrosylprotein sulfotransferase 2. Sequence alignments suggest that the sulfation of Tyr(154) is facilitated by a unique sequence context which is characteristically found in primate trypsinogens. In the search for genetic variants that might alter this sulfation motif, we identified a single nucleotide polymorphism (c.457G>C) in the PRSS2 (serine protease 2, human anionic trypsinogen) gene, which changed Asp(153) to a histidine residue (p.D153H). The p.D153H variant is common in subjects of African origin, with a minor allele frequency of 9.2%, whereas it is absent in subjects of European descent. We demonstrate that Asp(153) is the main determinant of tyrosine sulfation in anionic trypsinogen, as both the natural p.D153H variation and the p.D153N mutation result in a complete loss of trypsinogen sulfation. In contrast, mutation of Asp(156) and Glu(157) only slightly decrease tyrosine sulfation, whereas mutation of Gly(151) and Pro(155) has no effect. With respect to the biological relevance of the p.D153H variant, we found that tyrosine sulfation had no significant effect on the activation of anionic trypsinogen or the catalytic activity and inhibitor sensitivity of anionic trypsin. Taken together with previous studies, the observations of the present study suggest that the primary role of trypsinogen sulfation in humans is to stimulate autoactivation of PRSS1 (serine protease 1, human cationic trypsinogen), whereas the sulfation of anionic trypsinogen is unimportant for normal digestive physiology. As a result, the p.D153H polymorphism which eliminates this modification could become widespread in a healthy population.     

Diprotin A, an inhibitor of dipeptidyl aminopeptidase IV(EC 3.4.14.5) produces naloxone-reversible analgesia in rats

The dipeptidyl aminopeptidase IV (DP IV) inhibitor Diprotin A produces a full, dose-dependent, short-lasting and naloxone-reversible analgesia in the rat tail-flick test when given intracerebroventricularly, with an ED50 of 295 nmol/rat but it has no direct opioid agonist activity in the longitudinal muscle strip of guinea-pig ileum bioassay. Two of the potential DP IV substrates, morphiceptin and endomorphin 1, identified recently in bovine brain were also analgesic given by similar route. The action of endomorphin 1 was more potent (ED50 = 7.9 nmol/rat) and slightly but significantly more sustained than that of Diprotin A. Diprotin A neither potentiated nor prolonged the effect of a marginally analgesic dose of endomorphin 1. The distinct time course and the lack of potentiation indicate that in the analgesic effect of Diprotin A in rats the protection of a brain Tyr-Pro-peptide other than endomorphin 1 is involved.     

Endomorphin synthesis in rat brain from intracerebroventricularly injected [3H]-Tyr-Pro: a possible biosynthetic route for endomorphins

In spite of concentrated efforts, the biosynthetic route of mu-opioid receptor agonist brain tetrapeptide endomorphins (Tyr-Pro-Trp-Phe-NH2 and Tyr-Pro-Phe-Phe-NH2), discovered in 1997, is still obscure. We report presently that 30 min after intracerebroventricular injection of 20 or 200 microCi [3H]Tyr-Pro (49.9 Ci mmol(-1)) the incorporated radioactivity was found in endomorphin-related tetra- and tripeptides in rat brain extracts. As detected by the combination of HPLC with radiodetection, a peak corresponding to endomorphin-2-OH could be identified in two of four extracts of "20 microCi" series. Radioactive peaks in position of Tyr, Tyr-Pro, Tyr-Pro-Phe or Tyr-Pro-Trp appeared regularly in both series and also in the "tetrapeptide cluster" constituted by endomorphins and their free carboxylic forms. In one of the four extracts in the "200 microCi" series a robust active peak in the position of endomorphin 2 could be detected. Intracerebroventricularly injected 100 nmol, but not 10 or 1000 nmol cold Tyr-Pro (devoid of opioid activity in vitro), caused a naloxone-reversible prolongation of tail-flick latency in rats, peaking between 15 and 30 min. We suggest that Tyr-Pro may serve as a biosynthetic precursor to endomorphin synthesis.     

超临界CO2提取茶籽油的工艺及其成分分析

对超临界CO2工艺提取茶籽油进行研究,选择萃取压力、温度、时间、分离釜Ⅰ压力为影响因素,茶籽油的提取率为试验指标,采用多因素多水平可视化分析方法对数据进行分析,得出最佳工艺范围：萃取压力2.5×107～3.0×107Pa、温度30～35℃、时间110～140 min、分离釜Ⅰ压力4.0×106～5.0×106Pa。并用气相色谱-质谱法测定茶籽油中的各个成分及含量,发现茶籽油中单不饱和脂肪酸主要为油酸,多不饱和脂肪酸主要为亚油酸,饱和脂肪酸主要为棕榈酸和硬脂酸。     

Partial and full agonism in endomorphin derivatives: comparison by null and operational model

The partial mu-opioid receptor pool inactivation strategy in isolated mouse vas deferens was used to determine partial agonism of endomorphins and their analogs (endomorphin-1-ol, 2',6'-dimethyltyrosine (Dmt)-endomorphin-1, endomorphin-2-ol and (D-Met2)-endomorphin-2) using morphine, normorphine, morphiceptin, (D-Ala2,MePhe4,Gly5-ol)-enkephalin (DAMGO) and its amide (DAMGA) as reference opioid agonists. Agonist affinities (KA) and efficacies were assessed both by the "null" and the "operational" method. The KA values determined by the two methods correlated significantly with each other and also with the displacing potencies against 3H-naloxone in the receptor binding assay in the presence of Na+. DAMGO and DAMGA were full agonist prototypes, morphine, endomorphin-1, endomorphin-1-ol, Dmt-endomorphin-1, endomorphin-2-ol and (D-Met2)-endomorphin-2 were found by both methods to be partial agonists whereas the parameters for normorphine, morphiceptin and endomorphin-2 were intermediate.     

超临界二氧化碳萃取亚麻籽油工艺的可视化分析

对采用超临界二氧化碳技术萃取亚麻籽油进行较为系统的研究.选择萃取压力、萃取温度、萃取时间、分离压力4个主要影响因素,运用多因素多水平可视化设计法(m2VD)安排试验.选择分离釜1中产物的质量为试验指标,用自主提出的多因素多水平试验结果可视化分析方法(m2VA)对多维空间试验数据进行分析.得出最佳工艺范围为萃取压力20～ 30 MPa、萃取温度30～46℃、萃取时间77～90 min、分离压力4.0 ～4.7和5.7～5.9 MPa.根据优化工艺范围,在萃取压力为25 MPa、萃取温度40℃、萃取时间83 min、分离压力4.3 MPa下重新试验得到22.87％的得率,对应于质量为34.3 g.     

Effect of different weaning ages (21, 28 or 35 days) on production, growth and certain parameters of the digestive tract in rabbits

The effect of different weaning ages, that is, 21 (G21), 28 (G28) or 35 (G35) days, on growth and certain parameters of the digestive tract was examined in rabbits to assess the risk of early weaning attributable to the less-developed digestive system. On days 35 and 42, G35 rabbits had 10% to 14% and 10% higher BW, respectively (P < 0.05), than those weaned at days 21 and 28. In the 4th week of life, early weaned animals had 75% higher feed intake than G28 and G35 rabbits (P < 0.05). The relative weight of the liver increased by 62% between 21 and 28 days of age, and thereafter it decreased by 76% between 35 and 42 days of age (P < 0.05), with G21 rabbits having 29% higher weight compared with G35 animals on day 35 (P < 0.05). The relative weight of the whole gastrointestinal (GI) tract increased by 49% and 22% after weaning in G21 and G28 rabbits, respectively (P < 0.05). On day 28, the relative weight of the GI tract was 19% higher in G21 than in G28 rabbits, whereas on day 35 G21 and G28 animals had a 12% heavier GI tract compared with G35 rabbits (P < 0.05). Age influenced the ratio of stomach, small intestine and caecum within the GI tract; however, no effect of different weaning age was demonstrated. The pH value of the stomach and caecum decreased from 5.7 to 1.6 and from 7.1 to 6.3, respectively, whereas that of the small intestine increased from 6.8 to 8.4 (P < 0.05); the differences between groups were not statistically significant. Strictly anaerobic culturable bacteria were present in the caecum in high amounts (108), already at 14 days of age; no significant difference attributable to weaning age was demonstrable. The concentration of total volatile fatty acids (tVFA) was higher in G21 than in G28 and G35 throughout the experimental period (P < 0.05). The proportion of acetic and butyric acid within tVFA increased, whereas that of propionic acid decreased, resulting in a C3 : C4 ratio decreasing with age. Early weaning (G21) resulted in higher butyric acid and lower propionic acid proportions on day 28 (P < 0.05). No interaction between age and treatment was found, except in relative weight of the GI tract and caecal content. In conclusion, early weaning did not cause considerable changes in the digestive physiological parameters measured, but it resulted in 10% lower growth in rabbits.     

Detection of a novel immunoreactive endomorphin 2-like peptide in rat brain extracts

To pursue further the possible de novo biosynthetic pathway of endomorphins in rat brain we raised antibodies to endomorphin-2 conjugate in rabbits. Antiserum R1 recognized endomorphin-2 with good selectivity as compared to endomorphin-1 with a median detection value of 65.5+/-7.5 pg/tube (n=7), whereas R4 antiserum recognized both endomorphins with similar sensitivity. Neither antisera recognized YP-related di- or tripeptides or YGGF-related opioid sequences (enkephalins, beta-endorphin, dynorphin). Using the same rat brain extraction-RP-HPLC-gradient separation paradigm as previously, antisera detected 144.6+/-40.0 (n=3) pg/g wet brain weight endomorphin-2-like immunoreactivity in the fraction corresponding to standard endomorphin-2 retention time and also in the fraction matching endomorphin-2-OH standard retention time (179.1+/-30.1 pg/g). Since R1 failed to recognize authentic endomorphin-2-OH, the second immunoreactive species must be different from both endomorphin-2 and endomorphin-2-OH. Possible biosynthetic intermediates to endomorphins, synthetic YPFFG and YPWFG had retention times close to the parent endomorphin standards in RP-HPLC gradient separation profile. The former was a mu-opioid receptor agonist of medium potency in the in vitro assays (rat brain RBA>P gamma S binding and mouse vas deferens), whereas the latter was a weak mu-opioid receptor agonist with a significant delta-opioid receptorial action as well and a definite indication of partial agonism.