Lung and chest wall mechanics in rabbits during high-frequency body-surface oscillation

In eight anesthetized and tracheotomized rabbits, we studied the transfer impedances of the respiratory system during normocapnic ventilation by high-frequency body-surface oscillation from 3 to 15 Hz. The total respiratory impedance was partitioned into pulmonary and chest wall impedances to characterize the oscillatory mechanical properties of each component. The pulmonary and chest wall resistances were not frequency dependent in the 3- to 15-Hz range. The mean pulmonary resistance was 13.8 +/- 3.2 (SD) cmH2O.l-1.s, although the mean chest wall resistance was 8.6 +/- 2.0 cmH2O.l-1.s. The pulmonary elastance and inertance were 0.247 +/- 0.095 cmH2O/ml and 0.103 +/- 0.033 cmH2O.l-1.s2, respectively. The chest wall elastance and inertance were 0.533 +/- 0.136 cmH2O/ml and 0.041 +/- 0.063 cmH2O.l-1.s2, respectively. With a linear mechanical behavior, the transpulmonary pressure oscillations required to ventilate these tracheotomized animals were at their minimal value at 3 Hz. As the ventilatory frequency was increased beyond 6-9 Hz, both the minute ventilation necessary to maintain normocapnia and the pulmonary impedance increased. These data suggest that ventilation by body-surface oscillation is better suited for relatively moderate frequencies in rabbits with normal lungs.     

Tobacco (Nicotiana tobaccum) nuclear transgenics with high copy number can express NPTII driven by the chloroplast psbA promoter

A chloroplast expression vector containing the NPTII gene under the control of apsbA promoter (psbA-NPTII) was constructed, and was biolistically delivered into both suspension cells and leaf strips of tobacco (Nicotiana tabaccum). Analyses of subsequently recovered kanamycin-resistant transgenic plants indicate that the psbA-NPTII gene was not located in the chloroplast, but was in the nucleus in very high copy number. This conclusion was based upon results from: (1) Southern hybridization analyses of chloroplast and nuclear DNAs using NPTII, chloroplast-marker, and nuclear-marker probes; (2) pulse-field gel electrophoresis; and (3) kanamycin screening of sexual progenies. This study suggests that the nuclear expression of the NPTII gene may have been associated with many copies of the psbA-NPTII construction. Very high copy number in the nucleus might either allow NPTII expression from the otherwise inadequate psbA promoter, or might increase the chance of recombining with upstream tobacco regulatory sequences.     

鹤顶兰胚囊发育过程中微管变化的共焦显微镜观察

光镜的观察确定了鹤顶兰（Ｐｈａｉｕｓ ｔａｎｋｅｒｖｉｌｌｉａｅ （Ａｉｔｏｎ） Ｂｌ．）胚囊发育属单孢子蓼型。应用免疫荧光标记技术及共焦镜观察了胚囊发育过程中微管分布的变化。当孢原细胞初形成时,细胞内的微管呈网状分布。之后,孢原细胞体积增大发育为大孢子母细胞。大孢子母细胞延长,进入减数分裂Ⅰ。微管由分裂前的网状分布变为辐射状排列。二分体的两个细胞内的微管分布一样,呈辐射状。四分体的近珠孔端的３ 个大孢子解体,细胞内的微管消失。靠合点端的功能大孢子内有许多微管呈网状分布。当功能大孢子进入第一次有丝分裂时,细胞内的微管由网状变为辐射状,从核膜伸展至周质。再经两次有丝分裂形成八核胚囊。在核分裂之前微管一般是呈网状分布并紧包围着核。在分裂期间二核和四核胚囊都呈极性现象,微管系统也呈极性分布。微管在八核胚囊内的分布变化情形特别复杂。首先,八核分别作不同程度的移动,其中两个核移向胚囊中央,珠孔端和合点端的３ 个核分别互相靠拢,形成３ 个区,即中央区、反足区和卵器区。胚囊未形成区时,８ 个核都被网状分布的微管包围着。当胚囊明显分成区时,反足区内的微管仍作网状分布。中央区的微管分布则趋疏松,形成篮形结构,包围着液泡和两个极核。在     

Induction of cysteine and serine proteases during xylogenesis in Zinnia elegans

The terminal process of xylogenesis, autolysis, is essential for the formation of a tubular system for conduction of water and solutes throughout the whole plant. Several hydrolase types are implicated in autolysis responsible for the breakdown of cytoplasm. Here, we characterize p48h-17 cDNA from in vitro tracheary elements (TEs) of Zinnia elegans which encodes a preproprotein similar to papain. The putative mature protein, a cysteine protease, has a molecular mass of 22,699 Da with a pI of 5.7. DNA gel blot analysis indicated that p48h-17 is likely encoded by one or two genes. The p48h-17 mRNA accumulated markedly in in vitro differentiating TEs, whereas it appeared not to be induced in response to senescence and wounding in the leaves or H₂O₂ challenge in the cultured mesophyll cells. In stems, the expression of the p48h-17 gene was preferentially associated with differentiating xylem. Activity gel assays demonstrated that a cysteine and a serine protease, which had apparent molecular masses of 20 kDa and 60 kDa, respectively, were markedly induced during in vitro TE differentiation. The cysteine protease activity was also preferentially present in the xylem of Zinnia stems. Transient expression of the p48h-17 cDNA in tobacco protoplasts resulted in the production of a 20 kDa cysteine protease. Taken together, the results indicate that the p48h-17 gene appears to be preferentially associated with xylogenesis, and both the cysteine and serine proteases might be involved in autolysis during xylogenesis.     

RFLP mapping of QTLs for yield and related characters in rice (Oryza sativa L.)

Quantitative triat loci (QTLs) for yield and related traits in rice were mapped based on RFLP maps from two indica/indica F₂ populations, Tesanai 2/CB and Waiyin 2/CB. In Tesanai 2/CB, 14 intervals carrying QTLs for eight traits were detected, including 3 for grain weight per plant (GWT), 2 for number of panicles per plant (NP), 2 for number of grains per panicle (NG), 1 for total number of spikelets per panicle (TNS), 1 for spikelet fertility (SF), 3 for 1000-grain weight (TGWT), 1 for spikelet density (SD), and 1 for number of first branches per main panicle. The 3 QTLs for GWT were located on chromosomes 1, 2, and 4, with 1 in each chromosome. The additive effect of the single locus ranged from 2.0 g to 9.1 g. A major gene (np4) for NP was detected on chromosome 4 within the interval of RG143–RG214, about 4cM for RG143, and this locus explained 26.1% of the observed phenotypic variance for NP. The paternal allele of this locus was responsible for reduced panicles per plant (3 panicles per plant). In another population, Waiyin 2/CB, 12 intervals containing QTLs for six of the above-mentioned traits were detected, including 3 for GWT, 2 for each of NP, TNS, TGWT and SD, 1 for SF. Three QTLs for GWT were located on chromosome 1, 4, and 5, respectively. The additive effect of the single locus for GWT ranged from 6.7 g to 8.8 g, while the dominance effect was 1.7–11.5 g. QTL mapping in two populations with a common male parent is compared and discussed.     

Site-specific integration of the phage ΦCTX genome into the Pseudomonas aeruginosa chromosome: characterization of the functional integrase gene located close to and upstream of attP

The site-specific integration of the phage ?CTX genome, which carries the gene for a pore-forming cytotoxin, into the Pseudomonas aeruginosa chromosome was analysed. The 1,167 by integrase gene, int, located immediately upstream of the attachment site, attP, was characterized using plasmid constructs, harbouring the integration functions, and serving as an integration probe in both P. aeruginosa and Escherichia coli. The attP plasmids p1000/p400 in the presence of the int plasmid pIBH and attP-int plasmids pINT/pINTS can be stably integrated into the P. aeruginosa chromosome. Successful recombination between the attP plasmid p1000 and the attB plasmid p5.1, in the presence of the int plasmid pIBH in E. coli HB101 showed that the int gene is active in trans in E. coli. The int gene product was detected as a 43 kDa protein in E. coli maxicells harbouring pINT. Proposed integration arm regions downstream of attP are not necessary for the integration process. pINT and phage ?CTX could be integrated together into P. aeruginosa chromosomal DNA, yielding double integrates.     

猪脑组织水解液及其益智食品的研制

本文初步探讨了多脂质物质（脑组织）水解条件的优化过程及其益智产品的研制。经过多项对比实验得出了以双酶分段水解以及水化法除脂质提取脑组织水解液的初步工艺,并通过微震化工艺达到了掩蔽不良气味,稳定有效成分的效果。     

以融合蛋白形式在大肠杆菌中表达人MCP－1

将编码人单核细胞趋化蛋白－１（ＭＣＰ－１）的基因亚克隆到大肠杆菌表达载体ｐＥＸ３１Ａ中,在大肠杆菌中表达出ＭＳ２／ＭＣＰ－１融合蛋０白,该表达产物约占菌体总蛋白的１５％左右,Ｗｅｓｔｅｒｎｂｌｏｔ检测表明,表达产物可与ＭＣＰ－１抗体特异反应。采用琼脂糖平板法进行活性测定表明,表达产物具有明显的单核细胞趋化活性,说明Ｎ端融合一段细菌蛋白对ＭＣＰ－１有无趋化活性可能没有影响。