Regulation of the maizerab17 gene promoter in transgenic heterologous systems

The maizerab17 gene is expressed in different plant parts in response to ABA and osmotic stress (J. Vilardellet al., Plant Mol Biol 14 (1990) 423–432). Here we demonstrate that 5 upstream sequences of therab17 gene confer the appropriate patterns of expression on the chloramphenicol acetyl transferase (CAT) reporter gene in transgenic tobacco plants, as well as in protoplasts derived from cultured rice cells. Specifically, a CAT construct containing a large 5 upstream fragment ofrab17 (–1330/+29) results in high levels of CAT activity in embryos, leaves and roots of transgenic plants subjected to water stress or ABA treatment. Transient expression assays in rice protoplasts transfected with CAT genes fused torab17 promoter deletions indicate that a 300 bp DNA fragment (–351/–102) is sufficient to confer ABA responsiveness upon the reporter gene. Furthermore, a 100 bp sequence (–219/–102) is capable of conferring ABA responsiveness upon a minimal promoter derived from the 35S CaMV promoter. Gel retardation experiments indicate that maize nuclear proteins bind to this fragment. This region of 100 bp contains a sequence (ACGTGGC) which has been identified as an abscisic acid response element in studies of other ABA-responsive plant genes.     

试论用17荧光雌酮测定雌激素受体和生化法的关系

本文对采用细胞化学法测定乳腺癌内雌激素受体[ER]所用的荧光配体17-FE是否也是与ER上结合位点相结合的问题进行了探讨。在测定17-FE对[~3H]E_2与兔子宫上清液内ER结合的影响后,指出:17-FE对[~3H]E_2与ER的结合具有抑制作用,且其抑制作用随着17-FE浓度的提高而加大。在一系列不同浓度[~3H]E_2下测定其与ER的特异结合,同时测定加入不同浓度17-FE后的特异结合量,以Lineweaver-Burk和Scate-bard法分别作图。分析结果均显示为竞争性抑制曲线,可见17-FE和[~3H]E_2一样是与兔子宫上清液内ER上的结合位点相结合的。因此采用细胞化学法测定ER时,17-FE是一理想的配体。     

The integrated and free states of Streptomyces griseus plasmid pSG1

A 16.6-kb plasmid-pSG1-was isolated from Streptomyces griseus following transformation of protoplasts with unrelated plasmids. Southern hybridization experiments with radioactive probes prepared from pSG1 fragments and immobilized S. griseus DNA fragments indicated that the plasmid was present in the progenitor strain, in an integrated state. In the pSG1+ isolates plasmid sequences existed both as integrated sequences and as free plasmids. The integrated state of maintenance persisted in strains which have been cured of the free plasmid. The junction site on the plasmid was located on a 0.5-kb EcoRI-SalI fragment. The chromosomal integration site was demonstrated to be the same in all strains derived from S. griseus NRRL3851. The occurrence of both states of plasmid maintenance in the same clones indicates that an integrated pSG1 sequence does not interfere with free plasmid replication and partition. It suggests that the establishment of the free state may involve a replicative excision of pSG1 from the S. griseus chromosome.     

Pollenfertility and seed formation in theOrnithogalum umbellatum/angustifolium complex (Liliaceae/Scilloideae)

The pollen fertility and seed formation of six species of theOrnithogalum umbellatum/angustifolium complex and of seven related species were studied. Four types of pollen grains could be recognized. The pollen fertility varied greatly in this complex and is not related to the ploidy level. The seed formation ofO. umbellatum showed an adaptation to a subcontinental-Mediterranean climate, that ofO. angustifolium to an Atlantic climate. In both cases raindrops seem to be important for pollination, in view of the absence of insect pollinators. After open pollination 113 seedlings were obtained in four species. Their chromosome numbers were determined. Nearly all the cultivated seedlings were aneuploid, which points to a positive selection of euploids in nature, because aneuploid individuals are rare in the wild.Biosystematic Studies on theOrnithogalum umbellatum/angustifolium Complex III.—Previous parts of this series are Part I: Taxonomy. Proceeding Kon. Ned. Acad. Wet. series C,85 (4), 563–574 (1982) andvan Raamsdonk (1984).     

Lymphokines inhibit macrophage RNA synthesis

The effects of lymphokine (LK) preparations on the incorporation of [3H]uridine into macrophage RNA were investigated. Supernatants from murine spleen cells activated in vitro by alloantigens or Con A, and shown to contain macrophage-activating factor (MAF), were used as the source of LK. It was observed that such LK preparations contain factor(s) causing a profound inhibition of [3H]uridine incorporation into the RNA of proteose-peptone-elicited peritoneal macrophages. Such RNA-labeling inhibitory factor (RIF) was absent in control supernatants from nonstimulated cultures, and showed activation curves similar to that of MAF. RIF activity was not due to altered permeability of macrophages to [3H]uridine nor to the changes in the specific activity of the pool of RNA precursors, but rather reflected an altered metabolism of RNA. The inhibition of RNA synthesis was dependent upon the presence of nanogram amounts of LPS as a costimulator. Moreover, the response to RIF appeared to be genetically controlled since macrophages from C3H/HeJ mice were not affected by RIF, while C3H/HeN mice were fully responsive. In parallel cultures of macrophages, LK were also tested for their MAF activity, and a strong similarity between the biological conditions in which MAF and RIF activities were expressed could be demonstrated. The assay for RIF provides a new and convenient parameter for measuring macrophage-sensitive LK activity that might be very useful for monitoring purification or for screening of T-cell hybridoma supernatants.     

Relationship between chloroplast structure and O2 evolution rate of leaf discs in plants from different biotopes in South Finland

Abstract The chloroplast ultrastructure, especially the thylakoid organization, the polypeptide composition of the thylakoid membranes and photosynthetic O₂ evolution rate, chlorophyll (Chl) content and Chi a/b ratio were studied in leaves of nine plants growing in contrasting biotopes in the wild in South Finland. All the measurements were made at the beginning of the period of main growth on leaves approaching full expansion, when the CO₂-saturated O₂ evolution rate (measured at 20°C and 1500 μmol photons m^?2s^?1) was at a maximum, ranging from 19.2 to 6.9 μmol O₂ cm^?2 h^?1. Among the species, the Chi a/b ratio varied between 3.75 and 2.71. In the mesophyll chloroplasts, the ratio of the total length of appressed to non-appressed thylakoid membranes varied between 1.07 and 1.79, the number of partitions per granum varied between 2.8 and 12.0 and the grana area between 21 and 42% of the chloroplast area. There was a significant relationship between the rate of O₂ evolution of the leaf discs and the thylakoid organization in the mesophyll chloroplasts. The higher the O₂ evolution rate, the lower was the ratio of the total length of appressed to non-appressed thylakoid membranes and also the lower the grana area. Although the relationship of the photosynthetic rate with the Chi content and the Chi a/b ratio of the leaves was not as clear, a significant negative correlation existed between the Chi a/b ratio and the ratio of appressed to non-appressed thylakoid membranes, indicating lateral heterogeneity in the distribution of different Chl- protein complexes.     

Hydrogen peroxide formation and lipid peroxidation in rat uterus—effect of hormones and vitamin E

The effect of estradiol-17β and progesterone given separately as well as in combination on the rate of hydrogen peroxide formation and lipid peroxidation in the uteri of ovariectomized rats was studied. Estradiol in 3μg dose per day per animal elicited maximum stimulatory response and progesterone (100μg), on the other hand, was without any such effect. However, progesterone given along with estradiol completely prevented the effect due to the latter. In the same way, vitamin E, a well known antioxidant was found to be extremelv effective in protecting the uterus from the highly peroxidative action of estradiol-17β.     

Systematic study ofOsbertia (Asteraceae-Astereae)

Osbertia, a stoloniferous group confined to the montane regions of Mexico and adjacent Guatemala, was first proposed as a genus byGreene (1895), but most workers have retained the taxon as part ofHaplopappus. It is clearly closer toNoticastrum, Erigeron orHeterotheca than it is toHaplopappus sensu stricto. The present treatment recognizes two species, a widespread highly variableOsbertia stolonifera and a newly describedO. chihuahuana from northwestern Mexico. Distribution maps, distinguishing features, full synonymy and illustrations are presented.     

Isolation of a brain peptide identical to the intestinal PHI (peptide HI)

The isolation of a brain peptide identical to the intestinal peptide PHI (peptide HI) is described. The peptide was isolated from porcine brain extract using a chemical assay method based on its C-terminal isoleucine amide structure. The complete amino acid sequence of the peptide was found to be: His-Ala-Asp-Gly-Val-Phe-Thr-Ser-Asp-Phe-Ser-Arg-Leu-Leu-Gly-Gln-Leu-Ser-Ala- Lys-Lys-Tyr-Leu-Glu-Ser-Leu-Ile-NH2. This sequence is identical to the intestinal peptide thus demonstrating PHI to be a brain-gut peptide. The role of PHI in the central nervous system as a neurotransmitter or neuromodulator is discussed.     

Philomena oncorhynchi: Effect of hormones on maturation in anadromous sockeye, Oncorhynchus nerka

Adult sockeye salmon, Oncorhynchus nerka (Walbaum), treated with salmon pituitary extract in July survived for up to 47 days and developed nuptial colours in both male and female fish during this period, whereas no such characteristics appeared in untreated control fish. Furthermore, results showed that 20 of 50 adult female Philomena oncorhynchi recovered from the 15 treated fish contained fully developed tailed larvae in the uterus as compared with only one of 44 female P. oncorhynchi from 31 untreated control fish. None of 51 worms from 13 stilboestrol treated adult sockeye showed development in utero beyond an elongated embryo, nor did the host fish develop nuptial colours. P. oncorhynchi and its immature sockeye host (approx. 1 year prior to spawning) remained unaffected by any of three separate hormone treatment experiments using injection of salmon pituitary extract, injection of 17-β-estradiol, and stilboestrol mixed in the food.