应用RNA干扰沉默猪内源性反转录病毒

目的:尝试应用RNA干扰(RNAi)沉默猪源PK-15细胞中的猪内源性反转录病毒(PERV),并通过反转录酶活性及pol基因相对荧光定量PCR检测沉默效果。方法:依据GenBank公布的PERV pol基因序列,采用Invitro-gen公司的BLOCK-iT RNAi Designer软件设计Stealth小干扰RNA(siRNA)序列;将合成的siRNA转染PK-15细胞,72 h后检测细胞上清PERV反转录酶活性及细胞内pol基因拷贝数并评价沉默效果。结果:反转录酶活性及pol基因拷贝数检测结果表明,设计的3条Stealth siRNA序列中,位于pol基因3272～3296 bp的序列能有效沉默PERV。结论:RNAi方法可有效使猪源PK-15细胞中的PERV沉默,为进一步研究天然抗病毒分子与PERV的相互作用提供了实验基础,同时也为猪源异种移植研究中去除PERV提供了一种可供尝试的方法。     

缺血性脑卒中患者同型半胱氨酸代谢相关酶基因突变的研究

为研究同型半胱氨酸代谢相关酶亚甲基四氢叶酸还原酶(MTHFR)基因C677T和胱硫醚-β-合成酶(CBS)基因T833C位点碱基突变与缺血性脑卒中的关系,对74例缺血性脑卒中患者和83例健康对照者,采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术检测MTHFR基因C677T基因型,用扩增阻滞突变体系法(ARMS)检测CBS基因T833C突变。实验检出患者组MTHFR基因T纯合基因型、杂合基因型和T等位基因频率分别为2.7％、51.4％和28.4％,对照组分别为1.2％、39,8％和21.1％。患者组CBS基因C纯合基因型和C等位基因频率分别为13.5％和43.9％,对照组分别为6.0％和38.0％。Multiple Logistic Regression分析显示;C677T位点T等位基因,T833C位点C等位基因以及年龄均与缺血性脑卒中发病有关(P<0.05),C677T位点T等位基因的比值比(OR)为1.74(95％CI 1.06～2,B6)和T833C位点C等位基因的比值比为1.73(95％CI 1.07～-2.81)。实验显示MTHFR C677T和CBS T833C基因位点突变与缺血性脑卒中发病有关,上述两个基因位点突变可能是缺血性脑卒中发病的遗传因素。     

Tissue temperature profile in the human forearm during thermal stress at thermal stability.

The purpose of the present study was to investigate the effect of a range of water temperatures (Tw from 15 to 36 degrees C) on the tissue temperature profile of the resting human forearm at thermal stability. Tissue temperature (Tti) was continuously monitored by a calibrated multicouple probe during 3 h of immersion of the forearm. The probe was implanted approximately 9 cm distal from the olecranon process along the ulnar ridge. Tti was measured every 5 mm, from the longitudinal axis of the forearm (determined from computed tomography scanning) to the skin surface. Along with Tti, skin temperature (Tsk), rectal temperature (Tre), and blood flow were measured during the immersions. For all temperature conditions, the temperature profile inside the limb was linear as a function of the radial distance from the forearm axis (P less than 0.001). Temperature gradient measured in the forearm ranged from 0.2 +/- 0.1 degrees C C cm (Tw = 36 degrees C) to 2.3 +/- 0.5 degrees C cm (Tw = 15 degrees C). The maximal Tti was measured in all cases at the longitudinal axis of the forearm and was in all experimental conditions lower than Tre. On immersion at Tw less than 36 degrees C, the whole forearm can be considered to be part of the shell of the body. With these experimental data, mathematical equations were developed to predict, with an accuracy of at least 0.6 degrees C, the Tti at any depth inside the forearm at steady state during thermal stress.(ABSTRACT TRUNCATED AT 250 WORDS)     

Etiology and control of durian foliar blight and dieback caused by Rhizoctonia solani

Foliar blight and dieback of durian seedlings and trees in Peninsular Malaysia was found to be caused by Rhizoctonia solani (teleomorph - Thanatephoms cucumeris) The fungus grew well and produced abundant sclerotia at temperatures higher than 24°C with an optimum at 28°C. It grew poorly at 35°C and did not grow at 10°C. The strains studied were found to belong to the anastomosis group AG-1. They were pathogenic on durian, papaya, cucumber, long bean, Mikania weed, padi, musk melon, mung bean, Zoysia grass, Bermuda grass, and St Augustine grass. They were mildly pathogenic on groundnut, and non-pathogenic on maize, guava and Brassica‘pak choy’. The disease was effectively controlled by foliar sprays of pencycuron and benomyl; triadimefon and an antagonistic bacterium suspension treatment were less effective and quintozene-etridiazole mixture gave poor disease control.     

Direct evidence for the formation of a monolayer from a bilayer. An ellipsometric study at the nitrogen-water interface.

Direct evidence for the formation of a monolayer from a bilayer was measured by ellipsometry after spreading unilamellar vesicles of dioleoyl phosphatidylcholine (DOPC) at the nitrogen-water interface. The ellipsometric isotherms of DOPC vesicles and DOPC spread from an organic solvent were compared and found similar. From the observed ellipsometric angle (delta delta) in the plateau region (-1.04 degrees) and literature data for refractive indices of an anisotropic film similar to DOPC, we have calculated a thickness of 20 +/- 1 A. These results strongly suggest that, similarly to DOPC spread from an organic solvent, DOPC vesicles form a monolayer when spread at the nitrogen-water interface.     

2,3-Diarylthiophenes as selective EP1 receptor antagonists

The synthesis and the EP(1) receptor binding affinity of 2,3-diarylthiophene derivatives are described. The evaluation of the structure-activity relationship (SAR) in this series led to the identification of compounds 4, 7, and 12a, which exhibit high affinity for the human EP(1) receptor and a selectivity greater than 100-fold against the EP(2), EP(3), EP(4), DP, FP, and IP receptors and greater than 25-fold versus the TP receptor. These three antagonists present good pharmacokinetics in rats and significant differences in the way they are distributed in the brain.     

Growth Regulator Interactions in the Growth of the Shoot System of Avena sativa Seedling: II. THE GROWTH OF THE FIRST LEAF AND THE COLEOPTILE1

1. Studies have been made of the growth in culture medium of thecomponent parts of compositesegments excised from 3 to 7-day-oldAvena sativa seedlings and comprising portions of coleoptileand first leaf bases and various lengths of first internodetissue.
2. The effects of various concentrations of gibberellicacid (GA)and indole-3- acetic acid (IAA) alone and in combinationhavebeen studied on the growth of these organs.
3. Both GA andIAA stimulate the growth of coleoptile base tissuebut in combinationtheir joint effects are less than additive.No synergism occurs.
4. The growth of the first-leaf base is greatly stimulated byGAbut is inhibited by IAA. In combination, the stimulatoryeffectof GA (up to 1 0 p.p.m.) may be virtually eliminatedby evenlow concentrations of IAA (0.01 p.p.m.).
5. The inclusionof first internode tissue in the segments considerablyincreasesthe growth of first leaf base tissue but has no consistenteffecton the growth of coleoptile base tissue. The presenceof firstinternode tissue also greatly increases the degreeof growthstimulation invoked by GA but does not influence thedegreeof IAA inhibition. It is postulated that the first internodetissue is the source of an unknown growth factor necessary forGA action in the first leaf and potentiating the action of endogenousgibberellin.
6. Kinetin, adenine sulphate, glutarnine, glutarnicacid, asparagine,glycine, arginine, histidine, lysine, aneurin,and pyridoxinewill not simulate the effects of this unknowngrowth factorin the growth of leaf tissue. Like IAA, kinetinvirtually eliminatesthe GA stimulation of leaf growth.
7. Astudy of extracts of internode tissue in various solvents,analysedby paper partition chromatography and assayed by thegrowthof the first leaf base, has indicated the presence ofgrowthinhibitors and gibberellin-like substances but has failedtoisolate the postulated endogenous GA-synergist.
8. The implicationsof these results for growth correlations andthe hormone controlof shoot growth in Avena sativa seedlingsis discussed.

     

The Role of Anaerobic Respiration in Germinating Muskmelon Seeds: II. EFFECT OF ANOXIA TREATMENT AND ALCOHOL DEHYDROGENASE ACTIVITY

Exposing muskmelon (Cucumis melo L.) cultivar seedlots to N₂atmosphere created totally anaerobic conditions which stimulatedethanol production and accumulation in both high and low vigourseeds. However, accumulation of ethanol was consistently higherin the low vigour seeds than in the high vigour ones. In addition,CO₂ production under N₂ and in air suggests the presence ofan apparent ‘Pasteur effect’ in the low vigour seedsbut not in the high vigour seeds. Acetaldehyde production underN₂ was very low and did not seem to be associated with seedvigour, probably because of its nature as an intermediate inethanol production. The fast shift toward ethanol may be dueto the fact that alcohol dehydrogenase, the enzyme which catalyzesthe conversion of acetaldehyde to ethanol, exists in sufficientamounts in the imbibing seeds so that it is not a limiting factorin the conversion to ethanol. Alcohol dehydrogenase activitydid not appear to be related to seed vigour. Key words: Cucumis melo L., Anaerobic respiration, Germination, Seeds.