中国瓶尔小草科植物孢子形态的研究

利用扫描电镜对中国产瓶尔小草科2属7种的孢子进行了研究,其中包括瓶尔小草属6种,即裸茎瓶尔小草（OphioglossumnudicauleL．f）、尖头瓶尔小草（O．pedunculosumDesv．）、钝头瓶尔小草（O．petiolatumHook）、狭叶瓶尔小草（O．thermaleKom．）、心脏叶瓶尔小草（O．reticulatumL．）和瓶尔小草（O．vulgatumL．）,蛇蕨属1种,即蛇蕨（又名带状瓶尔小草OphiodermapendulaPresl）,对每个种的孢子形态特征进行描述。根据孢子形态特征,我们认为将中国的瓶尔小草科植物分为瓶尔小草属和蛇蕨属两个属是合适的。通过观察,进一步认定孢子外壁的纹饰特征极具分类参考价值,并可以作为种的界限的依据。     

晋西北3个树种抗旱性指数的研究

根据对海红、刺槐和柠条的ＰＶ曲线主要水分参数的测定,进行了抗旱性指数季节变化和种间排序分析。结果表明,树种的抗旱性随着年生长发育节律和环境水分条件而改变,其抗早性生长季初最弱,夏季高温干早阶段增强,秋季降雨峰期减弱,生长季末最强或很强。柠条的抗旱性与海红很接近。这对黄土高原地区果树和饲料的开发与水土保持树种的推广有重要意义。     

酵母pro 2基因转化紫云英的研究

用外植体一农杆菌共培养法将酵母脯氨酸合成酶基因2(pro 2)导入豆科牧草紫云英,获得转基因植株。Southern blot分析检测到转化植株基因组中存在外源DNA的同源顺序,证明酵母pro 2基因已整合到紫云英细胞基因组中。转化植株具有强的NPT Ⅱ酶活性,而对照植株呈阴性反应。在含0.5%NaCl的培养基上,紫云英植株内游离脯氨酸含量增高,一些转化植株叶片内游离脯氨酸含量显著高于对照,而且耐盐性有所提高。转化植株移栽到土壤中开花结实,收获到R_1代种子。     

Acute blood pressure elevation during repetitive hypocapnic and eucapnic hypoxia in rats

Bao, Gang, Preet M. Randhawa, and Eugene C. Fletcher.Acute blood pressure elevation during repetitive hypocapnic and eucapnic hypoxia in rats. J. Appl.Physiol. 82(4): 1071-1078, 1997.Using a ratmodel, we investigated whether episodic eucapnic hypoxia was a morepotent stimulus to acute blood pressure (BP) elevation and bradycardiathan episodic hypocapnic hypoxia. We also investigated therole of sympathetic and parasympathetic nervous system in thiscardiovascular response. Sprague-Dawley (SD) and Wistar Kyoto (WKY)rats were exposed to repetitive 30-s cycles of hypocapnic or eucapnichypoxia before and after intravenous injection of the₁-adrenergic blocker prazosin,₂-adrenergic blocker yohimbine,or atropine. Eucapnic hypoxia caused a threefold elevation in systolicBP from baseline (83.5 ± 3.5 mmHg in WKY, 70.6 ± 4.6 mmHg inSD) and greater bradycardia (178 ± 20 beats/min in WKY,178 ± 21 beats/min in SD) compared with hypocapnic hypoxia (29.8 ± 3.6 mmHg and 43 ± 15 beats/min in WKY,19.0 ± 4.1 mmHg and 45 ± 12 beats/min in SD). Afterprazosin, the BP increase from eucapnic hypoxia was blunted, yohimbineshowed no effect, and atropine blocked the bradycardia. Directmeasurement of sympathetic nerve activity confirmed that addingCO₂ to the hypoxic gas mixture caused a 61% increase in sympathetic nerve activity. WKY rats seemmore vulnerable than SD rats to both hypoxia exposures in terms of theelevation in BP. We conclude that, in the rat, eucapnic hypoxia is amore potent stimulus to acute BP elevation and bradycardia than ishypocapnic hypoxia. An increased sympathetic tone appears to beinvolved in the BP response to acute episodic hypoxia.

     

Blood pressure response to chronic episodic hypoxia: role of the sympathetic nervous system

Bao, Gang, Naira Metreveli, Rena Li, Addison Taylor, andEugene C. Fletcher. Blood pressure response to chronic episodic hypoxia: role of the sympathetic nervous system. J. Appl. Physiol. 83(1): 95-101, 1997.Previousstudies in several strains of rats have demonstrated that 35 consecutive days of recurrent episodic hypoxia (7 h/day) cause an 8- to13-mmHg persistent increase in diurnal systemic blood pressure (BP).Carotid chemoreceptors and the sympathetic nervous system have beenshown to be necessary for development of this BP increase. The presentstudy was undertaken to further define the role of renal arterysympathetic nerves and the adrenal medulla in this BPincrease. Male Sprague-Dawley rats had either adrenalmedullectomy, bilateral renal artery denervation, or sham surgery. Ratsfrom each of these groups were subjected to episodic hypoxia for 35 days. Control groups received either compressed air or were leftunhandled. Adrenal demedullation or renal artery denervation eliminatedthe chronic diurnal mean BP response (measured intra-arterially) toepisodic hypoxia, whereas sham-operated controls continued to showedpersistent elevation of systemic BP. Plasma and renal tissuecatecholamine levels at the end of the experiment confirmed successfuladrenal demedullation or renal denervation in the respectiveanimals. The chronic episodic hypoxia-mediated increase indiurnal BP requires both intact renal artery nerves as well as anintact adrenal medulla.

     

通过基因组相减从悬铃木突变体中分离缺失DNA

悬铃木（Ｐｌａｔａｎｕｓ ｏｃｃｉｄｅｎｔａｌｉｓ Ｌ．）突变体是其种子经γ射线辐射培育出的一种营养生长正常而开花发育过程受阻的不育植株。经过１０多年的观察研究证明：突变体的花芽不能形成是因为突变体细胞染色体有部分缺失。应用基因组相减技术分离这些在突变体中缺失但在野生型中存在的ＤＮＡ,经过４次循环富集缺失片段后克隆了１个２．０ ｋｂ 的ＤＮＡ 片段,ＤＮＡ 杂交证明此片段只存在于野生型基因组中而不存在于突变体中。将基因组相减方法应用在复杂植物基因组中获得成功的研究还未见报道     

CO2浓度倍增对谷子和紫花苜蓿叶绿体超微结构的效应

电镜观察结果表明,不同种类植物生长在相同倍增的高ＣＯ２ 浓度条件下,其叶绿体超微结构彼此呈现出明显的差异． 最醒目的特征是淀粉粒的积累比对照的增加很多;类囊体膜系发生异变． 总体上,（１）淀粉粒,Ｃ４ 植物谷子（Ｓｅｔａｒｉａ ｉｔａｌｉｃａ）叶绿体比Ｃ３ 植物紫花苜蓿（Ｍｅｄｉｃａｇｏ ｓａｔｉｖａ）积累的更多． （２）淀粉粒较小且较少时,紫花苜蓿叶绿体基粒类囊体膜增多,与基质类囊体膜相间排列有序;谷子叶绿体的基粒垛及基粒类囊体膜数均增多,但基粒变小,基质类囊体膜变长,且有些膜出现膨胀甚至破损． （３）淀粉粒较大且积累过多时,紫花苜蓿叶绿体中尚可隐约见到由４～８ 个类囊体膜组成的短小基粒零星分布于淀粉粒间;谷子叶绿体中几乎找不到可辨认的基粒和基质类囊体膜     

水稻巯基蛋白酶抑制剂的纯化及其性质研究

水稻的糠皮和胚经生理盐水浸取、离心后的上清液加热至８０℃处理１０ｍｉｎ,离心获得的上清液调ｐＨ至８．０,得到沉淀。沉淀溶解于０．０１ｍｏｌ／ＬＨＣｌ,经透析冷冻干燥得水稻巯基蛋白酶抑制剂（ＣＰＩ）粗品;粗品再经ＤＥＡＥ－Ｓｅｐｈａｒｏｓｅ柱线性离子梯度洗脱和ＳｅｐｈａｄｅｘＧ－１００柱分子筛层析,即可获得在ＰＡＧＥ、ＳＤＳ－ＰＡＧＥ和ＨＰＬＣ上均为单一蛋白带的ＣＰＩ样品。经上述步骤,ＣＰＩ可被纯化５８倍。经ＳｅｐｈａｄｅｘＧ－１００和ＳＤＳ－ＰＡＧＥ测定其分子量均为１２０００,Ｎ末端氨基酸为Ｐｒｏ,等电点５．６．水稻ＣＰＩ经１００℃处理１０ｍｉｎ后,其抑制活性无任何变化,在ｐＨ２．０～９．０之间,活性也不发生改变,但ｐＨ在９．０以上,其活性逐渐下降,水稻ＣＰＩ对木瓜蛋白酶是一种高亲和性的抑制剂,它对木瓜蛋白酶和无花果蛋白酶有强抑制作用,对菠萝蛋白酶仅有弱抑制作用,但对胰蛋白酶则全无抑制作用;其抑制类型属竞争性抑制剂类型,Ｋ＿ｉ值约３．５×１０￣（－８）ｍｏｌ／Ｌ对木瓜蛋白酶的抑制摩尔比约为１：１。     

Isolation and characterization of chromosome-specific DNA sequences from a chromosome arm genomic library of common wheat

Isolation, physical mapping and polymorphism of chromosome-specific DNA sequences in wheat are reported. Following the microdissection of the long arm of chromosome 5B (5BL) of common wheat, its DNA was amplified by degenerate oligonucleotide-primed PCR and directly cloned into plasmid vectors. Characterization of the chromosome arm library showed that ∼55% of the inserts are of low-copy nature. Southern analysis using aneuploid lines of common wheat revealed that five of 11 low-copy inserts analyzed map to chromosome arm 5BL; four of these are 5BL-specific. By deletion mapping, the 5BL-specific sequences were located to sub- chromosome arm regions. Based on the hybridization patterns of three 5BL-specific sequences to DNA from a diverse collection of goat-grass ( Aegilops ) and wheat ( Triticum ) species, it was concluded that these sequences emerged at different times in the course of evolution of this group of plant species.     

Painless Jaundice Caused by Clonorchis sinensis Infection: A Case Report

A man with only yellowing of the skin and eye sclera was diagnosed with clonorchiasis, which rarely manifested jaundice as the initial symptom. However, because of a lack of evidence for a diagnostic gold standard, the time until definitive diagnosis was more than a week. The diagnostic process relied on inquiring about the patient’s history, including the place of residence, dietary habits, and symptoms, as well as on serological findings, an imaging examination, and pathological findings. MRCP and CT results showed mild dilatation of intrahepatic ducts and increased periductal echogenicity. The eggs were ultimately found in stool by water sedimentation method after the negative report through direct smear. DNA sequencing of PCR production of the eggs demonstrated 98-100% homology with ITS2 of Clonorchis sinensis. After anti-parasite medical treatment, the patient’s symptoms were gradually relieved. Throughout the diagnostic procedure, besides routine examinations, the sedimentation method or concentration method could be used as a sensitive way for both light and heavy C. sinensis infection in the definite diagnosis.