小鼠卵激活过程中胞质游离Ca~(2 )的变化及孤雌发育研究

乙醇和电刺激均可使小鼠MⅡ期卵母细胞激活并在体外孤雌发育至囊胚。小鼠卵对乙醇十分敏感。用7%—8%乙醇处理5min后95%以上的卵母细胞(卵龄为HCG注射后18—19h)内形成原核。3—4次电刺激后卵的激活率为71.58%;仅刺激1次卵的激活率为63.63%。乙醇刺激可诱导卵内游离Ca~(2 )浓度出现多次升高;单一电刺激仅能诱导卵内游离Ca~(2 )浓度出现1次升高;多次电刺激可诱导卵内游离Ca~(2 )浓度多次升高,而且电刺激次数与Ca~(2 )浓度升高成一一对应关系。对于电刺激,介质中足够量的Ca~(2 )对卵激活至关重要。在无Ca~(2 )的介质中,电刺激很难使卵激活。正常受精刺激诱导卵内游离Ca~(2 )浓度出现多次有规律的升高。实验结果表明,卵母细胞激活过程中胞质游离Ca~(2 )浓度重复多次升高可促使卵母细胞恢复成熟分裂。     

慢性缺氧对大鼠左右心室功能、心肌肌原纤维Ca~（2＋），Mg~（2＋）－ATP

模拟５０００ｍ中度缺氧时,大鼠右室功能显著加强,而左室功能加强不显著;左右心室肌原纤维Ｃａ２＋,Ｍｇ２＋－ＡＴＰ酶活性下降,肌球蛋白同功酶Ｖ２和Ｖ３百分含量增加,Ｖ１百分含量减少。８０００ｍ重度缺氧时,右室功能减弱,但无统计学意义,左室功能减弱有显著性;ＡＴＰ酶活性和同功酶的变化超过５０００ｍ组。此外,右室ＡＴＰ酶活性与ＰＡＰ呈反比且有显著性,左室ＡＴＰ酶活性与ＣＡＳＰ虽也呈反比但无显著性;右室同功酶Ｖ３百分含量与ＰＡＰ呈正比,左室同功酶Ｖ３百分含量与ＣＡＳＰ不呈比例。上述结果表明,因短期突发严重缺氧引起的心肌供氧不足对左心室心肌的直接损伤作用大于右心室心肌。     

藻－菌生态系统代谢功能的生态学研究

在室内模拟条件下,研究了一些生态因子对藻－菌（Ａ＋Ｂ）生态系统代谢有机碳（Ｃ６Ｈ１２Ｏ６）、ＮＨ３－Ｎ和无机磷（ＩＰ）的影响．研究结果表明,当藻－菌生态系统中藻（Ａ）或菌（Ｂ）的起始数量一定时,其代谢Ｃ６Ｈ１２Ｏ６的速率,随与之组合的Ｂ或Ａ的起始数量增加（数量比则相应降低）而增加．在光照和黑暗条件下,Ａ＋Ｂ系统代谢上述３种营养物质的速率均有一定的差异．黑暗下Ｃ６Ｈ１２Ｏ６的平均代谢速率较光照下高１２．３％（Ｐ＜０．０５）,ＩＰ和ＮＨ３－Ｎ的平均代谢速率则分别较光照下低１４．４％（Ｐ＜０．０５）和１６．２％（Ｐ＜０．００１）．在Ａ＋Ｂ系统和Ａ、Ｂ单培养物中,３种营养物质的代谢速率均随有机负荷量增加而增加,而且Ａ＋Ｂ系统的代谢速率分别高于单培养的Ａ和Ｂ,其中ＮＨ３－Ｎ代谢尤为显著．文章还就生态系统结构与功能的关系问题进行了讨论．     

不同树种混交林及其纯林对土壤理化性质影响的研究

对针阔混交林土壤理化性质的研究表明,针阔混交林比针叶树纯林对土壤的改良作用要好,它使土壤总孔隙度增加２—１９％,水分含量增加６—３１％,枯枝落叶年凋落量增加２—２００％;土壤养分含量全Ｎ、ＮＨ４－Ｎ、代换性Ｃａ、代换性Ｍｇ和腐殖质含量分别增加４５—７５％、３３—８２％、５５—８５％、４４—８４％和３７—４６％．     

杉木连栽土壤对其幼树生长的影响

在会同林区采用３种不同连栽杉木次数的土壤,进行杉木幼树盆栽试验．结果表明,杉木连栽不利其幼树生长．连裁使幼树高生长下降３７—４０％,基径下降１９—２８％,冠幅下降２１—２９％,总生物量减少４５—５０％．杉木连栽还造成土壤养分递减,即腐殖质减少７—２８％,速效养分下降２３—２８％,土壤微生物数量和活性也大大降低．因此,杉木纯林连栽经营方式应尽快改变．     

Overexpression of Arabidopsis COP1 results in partial suppression of light-mediated development: evidence for a light-inactivable repressor of photomorphogenesis.

Arabidopsis seedlings are genetically endowed with the capability to follow two distinct developmental programs: photomorphogenesis in the light and skotomorphogenesis in darkness. The regulatory protein CONSTITUTIVE PHOTO-MORPHOGENIC1 (COP1) has been postulated to act as a repressor of photomorphogenesis in the dark because loss-of-function mutations of COP1 result in dark-grown seedlings phenocopying the light-grown wild-type seedlings. In this study, we tested this working model by overexpressing COP1 in the plant and examining its inhibitory effects on photomorphogenic development. Stable transgenic Arabidopsis lines overexpressing COP1 were generated through Agrobacterium-mediated transformation. Overexpression was achieved using either the strong cauliflower mosaic virus 35S RNA promoter or additional copies of the wild-type gene. Analysis of these transgenic lines demonstrated that higher levels of COP1 can inhibit aspects of photomorphogenic seedling development mediated by either phytochromes or a blue light receptor, and the extent of inhibition correlated quantitatively with the vivo COP1 levels. This result provides direct evidence that COP1 acts as a molecular repressor of photomorphogenic development and that multiple photoreceptors can independently mediate the light inactivation of COP1. It also suggests that a controlled inactivation of COP1 may provide a basis for the ability of plants to respond quantitatively to changing light signals, such as fluence rate and photoperiod.     

Arabidopsis COP8, COP10, and COP11 genes are involved in repression of photomorphogenic development in darkness.

Wild-type Arabidopsis seedlings are capable of following two developmental programs: photomorphogenesis in the light and skotomorphogenesis in darkness. Screening of Arabidopsis mutants for constitutive photomorphogenic development in darkness resulted in the identification of three new loci designated COP8, COP10, and COP11. Detailed examination of the temporal morphological and cellular differentiation patterns of wild-type and mutant seedlings revealed that in darkness, seedlings homozygous for recessive mutations in COP8, COP10, and COP11 failed to suppress the photomorphogenic developmental pathway and were unable to initiate skotomorphogenesis. As a consequence, the mutant seedlings grown in the dark had short hypocotyls and open and expanded cotyledons, with characteristic photomorphogenic cellular differentiation patterns and elevated levels of light-inducible gene expression. In addition, plastids of dark-grown mutants were defective in etioplast differentiation. Similar to cop1 and cop9, and in contrast to det1 (deetiolated), these new mutants lacked dark-adaptive change of light-regulated gene expression and retained normal phytochrome control of seed germination. Epistatic analyses with the long hypocotyl hy1, hy2, hy3, hy4, and hy5 mutations suggested that these three loci, similar to COP1 and COP9, act downstream of both phytochromes and a blue light receptor, and probably HY5 as well. Further, cop8-1, cop10-1, and cop11-1 mutants accumulated higher levels of COP1, a feature similar to the cop9-1 mutant. These results suggested that COP8, COP10, and COP11, together with COP1, COP9, and DET1, function to suppress the photomorphogenic developmental program and to promote skotomorphogenesis in darkness. The identical phenotypes resulting from mutations in COP8, COP9, COP10, and COP11 imply that their encoded products function in close proximity, possibly with some of them as a complex, in the same signal transduction pathway.     

HAPLOID PARTHENOGENETIC SPOROPHYTES OF LAMINARIA JAPONICA (PHAEOPHYCEAE)1

Parthenogenetic sporophytes were obtained from three strains of Laminaria japonica Areschoug. These sporophytes grew to maturity in the sea, producine spores that all grew into female gametophytes. These female gametophytes gave rise to another generation of parthenogenetic sporophytes during the next year, so that by the year 1990 parthenogenetic sporophytes had been cultivated for 12, 9, and 7 generations, respectively, for the three strains. When female gametophytes from parthenogenetic sporophytes were combined with normal male gametophytes, normal sporophytes that reproduced and gave rise to both female and male gametophytes were obtained. The parthenogenetic sporophytes were shorter and narrower than the normal sporophytes of the same strain. Chromosome counts on mature sporophytes showed that normal sporophytes (from fertilized eggs) were diploid (2n = approximately 40) and that the spores they produced were haploid (n = approximately 20), while nuclei from both somatic and sporangial cells in parthenogenetic sporophytes were haploid. All gametophytes were haploid. Young sporophytes derived from cultures with both female and male gametophytes were diploid, while young, sporophytes obtained from female gametophytes from parthenogenetic sporophytes had haploid, diploid, or polyploidy chromosome numbers. Polyploidy was associated with abnormal cell shapes. The presence of haploid parthenogenetic sporophytes should be use in breeding kelp strains with useful characteristics, since the sporophyte phenotype is expressed from a haploid genotype which can be more readily selected.     

巨噬细胞对正常人极低密度脂蛋白亚组分代谢的研究

本文研究了小鼠腹腔巨噬细胞对正常人极低密度脂蛋白(N-VLDL)两种亚组分VLDL_1和VLDL_3的代谢。两种亚组分都能以受体方式和非特异性方式被巨噬细胞摄取和降解。在受体途径中以VLDL_1的摄入量居多。对胞内甘油三酯(TG)的堆积作用以VLDL_1较强,对胆固醇酶(CE)的堆积则以VLDL_3较强。表明两者在促进巨噬细胞向泡沫细胞转变中的作用有所不同。     

外源DAN导入黄瓜引起变异的研究

利用花粉管通道技术,以抗黄瓜霜霉病的“苦瓜”“津四”黄瓜为供体,用“长春密刺”为受体,进行外源DNA直接导入,获得突变体,并得到遗传。