辽宁碱蓬甜菜碱醛脱氢酶基因(BADH)启动子分离及序列分析

根据已知的辽宁碱蓬BADHcDNA5′端序列设计两个基因特异的反向引物(BR1,BR2),通过衔接头PCR获得了BADH基因起始密码子上游265bp的序列。根据所获得的序列设计两个基因特异的反向引物(BR3,BR4),用BR2、BR3、BR4分别与4个简并引物配对,通过TAILPCR扩增,获得了约2kb的序列。经Sequencer软件拼接上述两段序列,获得了BADH基因起始密码子上游2055bp的序列。用TSSPTCM软件分析此序列,预测出转录起始点(T)位于起始密码子上游62bp处,由此获得了1993bp的SlBADH启动子序列。用PLACE软件分析此序列,发现该序列具有启动子的基本元件TATAbox、CAATbox,包含多个胁迫诱导元件,如盐诱导元件GAAAAA,抗冻、缺水、脱落酸、抗寒元件CANNTG,伤害诱导元件ANATTNCNN,热激元件ATAAATGT等,是一个强的胁迫诱导启动子。     

Abscisic acid regulation of gene expression during water-deficit stress in the era of the Arabidopsis genome

Changes in gene expression may lead to cellular adaptation of water-deficit stress, yet all of the induced mRNAs may not play this role. Changes in gene expression must be signalled by transduction mechanisms that first sense a water deficit. This first step triggers changes in gene expression that function to synthesize additional signals such as abscisic acid (ABA). The enzymes involved in ABA biosynthesis have been cloned and their regulation during water-deficit stress is being characterized. Once ABA levels are increased, further signalling mechanisms are initiated to signal new gene expression patterns that are proposed to play a role in cellular adaptation to water-deficit stress. As the genome of Arabidopsis is now completed, much more information can be exploited to characterize these responses.     

Enhancement of coenzyme binding by a single point mutation at the coenzyme binding domain of E. coli lactaldehyde dehydrogenase

Phenylacetaldehyde dehydrogenase (PAD) and lactaldehyde dehydrogenase (ALD) share some structural and kinetic properties. One difference is that PAD can use NAD+ and NADP+, whereas ALD only uses NAD+. An acidic residue has been involved in the exclusion of NADP+ from the active site in pyridine nucleotide-dependent dehydrogenases. However, other factors may participate in NADP+ exclusion. In the present work, analysis of the sequence of the region involved in coenzyme binding showed that residue F180 of ALD might participate in coenzyme specificity. Interestingly, F180T mutation rendered an enzyme (ALD-F180T) with the ability to use NADP+. This enzyme showed an activity of 0.87 micromol/(min * mg) and K(m) for NADP+ of 78 microM. Furthermore, ALD-F180T exhibited a 16-fold increase in the V(m) /K(m) ratio with NAD+ as the coenzyme, from 12.8 to 211. This increase in catalytic efficiency was due to a diminution in K(m) for NAD+ from 47 to 7 microM and a higher V(m) from 0.51 to 1.48 micromol/(min * mg). In addition, an increased K(d) for NADH from 175 (wild-type) to 460 microM (mutant) indicates a faster product release and possibly a change in the rate-limiting step. For wild-type ALD it is described that the rate-limiting step is shared between deacylation and coenzyme dissociation. In contrast, in the present report the rate-limiting step in ALD-F180T was determined to be exclusively deacylation. In conclusion, residue F180 participates in the exclusion of NADP+ from the coenzyme binding site and disturbs the binding of NAD+.     

一株乙醇降解菌株的分离和鉴定

从湖北农田土壤中筛选得到一株ALDH活性较高的菌株,该菌株在含0．64％乙醇的培养基中生长较佳,且耐受0．9％的乙醛。经菌种形态学和生理生化特征,以及16S rRNA基因序列分析,鉴定该菌株为不动杆（Acinetobacter sp．）。该菌株在乙醇和乙醛解毒研究中有重要价值。     

Neurochemical Mechanisms Underlying Alcohol Addiction: Model Experiments on Rats

We measured the activities of the main alcohol-metabolizing enzymes (alcohol dehydrogenase, AlDH, and aldehyde dehydrogenase, AdhDH) in the blood serum, comparing these indices with the contents of ethanol and its main metabolite, acetaldehyde (AcAdh), in the blood, and also measured the contents of catecholamines (adrenaline, noradrenaline, and dopamine) in the blood and in different brain structures (hypothalamus, midbrain, and neocortex) of rats in the states of acute alcohol intoxication and chronic alcohol addiction. It was shown that, because of dissimilar changes in the activities of AlDH and AdhDH under conditions of alcohol intoxication, the dynamic balance between endogenous ethanol and AcAdh existing in the norm is disturbed, which results in an increase in the level of AcAdh. Such a phenomenon probably is one of the crucial factors underlying the development of alcohol addiction.     

Geranylgeranoic acid,a bioactive and endogenous fatty acid in mammals: a review

Geranylgeranoic acid (GGA) was first reported in 1983 as one of the mevalonic acid metabolites, but its biological significance was not studied for a long time. Our research on the antitumor effects of retinoids led us to GGA, one of the acyclic retinoids that induce cell death in human hepatoma-derived cell lines. We were able to demonstrate the presence of endogenous GGA in various tissues of male rats, including the liver, testis, and cerebrum, by LC-MS/MS. Furthermore, the biosynthesis of GGA from mevalonic acid in mammals including humans was confirmed by isotopomer spectral analysis using ¹³C-labeled mevalonolactone and cultured hepatoma cells, and the involvement of hepatic monoamine oxidase B in the biosynthesis of GGA was also demonstrated. The biological activity of GGA was analyzed from the retinoid (differentiation induction) and nonretinoid (cell death induction) aspects, and in particular, the nonretinoid mechanism by which GGA induces cell death in hepatoma cells was found to involve pyroptosis via ER stress responses initiated by TLR4 signaling. In addition to these effects of GGA, we also describe the in vivo effects of GGA on reproduction. In this review, based mainly on our published papers, we have shown that hepatic monoamine oxidase B is involved in the biosynthesis of GGA and that GGA induces cell death in human hepatoma-derived cell lines by noncanonical pyroptosis, one of the mechanisms of sterile inflammatory cell death.     

Natural Monoterpenes: Much More than Only a Scent

Terpenes are a widespread group of secondary metabolites that can be found in various family plants such as the Lamiaceae. In view of their numerous valuable biological activities, the industrial production of concrete terpenes and essential oils rich in the substances is intensively studied. Monoterpenes constitute a significant part of the whole group of the aforementioned secondary metabolites. This is due to their numerous biological activities and their ability to permeate the skin. Despite the fact that these substances have gain popularity, they are not comprehensively characterized. The presented review is based on studies of the biological activities of the most important monoterpenes and the essential oils rich in these compounds. The authors focused attention on antioxidant activity, inhibition towards acetyl‐ and butyrylcholinesterase, and α‐amylase and α‐glucosidase, antifungal, hepatoprotective, sedative properties, and their skin permeation enhancement.     

Triterpenes in organ pipe cactus

Twelve triterpenes in the lup-20(29)-ene and olean-12-ene series have been isolated from the triterpene glycoside and lipid fractions of organ pipe cactus. Physical properties and chromatographic mobilities of these compounds and some of their derivatives are given and they are arranged in a biosynthetic scheme based on degree of oxidation. Betulinic and oleanolic aldehydes, two of the cactus triterpenes, were also synthesized and fully characterized.     

New heliangolides from Calea oxylepis

An investigation of the roots and aerial parts of Calea oxylepis afforded, in addition to known compounds, three new heliangolides and an unusual monoterpene triacetate.