Isolation of an efficient actin promoter for use in rice transformation

We have characterized the 5' region of the rice actin 1 gene (Act1) and show that it is an efficient promoter for regulating the constitutive expression of a foreign gene in transgenic rice. By constructing plasmids with 5' regions from the rice Act1 gene fused to the coding sequence of a gene encoding bacterial beta-glucuronidase, we demonstrate that a region 1.3 kilobases upstream of the Act1 translation initiation codon contains all of the 5'-regulatory elements necessary for high-level beta-glucuronidase (GUS) expression in transient assays of transformed rice protoplasts. The rice Act1 primary transcript has a noncoding exon separated by a 5' intron from the first coding exon. Fusions that lack this Act1 intron showed no detectable GUS activity in transient assays of transformed rice protoplasts. Deletion analysis of the Act1 5' intron suggests that the intron-mediated stimulation of GUS expression is associated, in part, with an in vivo requirement for efficient intron splicing.

Isolation of an efficient actin promoter for use in rice transformation

We have characterized the 5' region of the rice actin 1 gene (Act1) and show that it is an efficient promoter for regulating the constitutive expression of a foreign gene in transgenic rice. By constructing plasmids with 5' regions from the rice Act1 gene fused to the coding sequence of a gene encoding bacterial beta-glucuronidase, we demonstrate that a region 1.3 kilobases upstream of the Act1 translation initiation codon contains all of the 5'-regulatory elements necessary for high-level beta-glucuronidase (GUS) expression in transient assays of transformed rice protoplasts. The rice Act1 primary transcript has a noncoding exon separated by a 5' intron from the first coding exon. Fusions that lack this Act1 intron showed no detectable GUS activity in transient assays of transformed rice protoplasts. Deletion analysis of the Act1 5' intron suggests that the intron-mediated stimulation of GUS expression is associated, in part, with an in vivo requirement for efficient intron splicing.

Inhibitory effects of ginsenoside Rg1 and Rb1 on rat brain microsomal Na+,K(+)-ATPase activity

Rat brain microsomal Na+, K(+)-ATPase activity was inhibited significantly and rapidly by ginsenoside Rb1. The IC50 of Rb1 for Na+,K(+)-ATPase was 6.3 +/- 1.0 mumol/L. The inhibition was enhanced with increasing the concentration of Rb1 or decreasing that of Na+ and K+. Kinetic analysis revealed that ginsenoside was an uncompetitive inhibitor with respect to ATP. The inhibitory effect of Rg1 on rat brain microsomal Na+,K(+)-ATPase was much weaker than that of Rb1.

[A study on indolepyruvic acid methyltransferase in chuangxinmycin-producing strain]

The indolepyruvic acid methyltransferase, perhaps which is active in the biosynthetic pathway of the antibiotic chuangxinmycin, has been detected and partially purified from cell-free extracts of Actinoplanes jinanensis n. sp., This enzyme catalyzes the transfer of a methyl group from S-adenosylmethionine to indolepyruvic acid. The methyltransferase has been purified 60-fold by ammonium sulfate fractionation and DEAE-cellulose column chromatography. The enzyme optimal substrate is indolepyruvic acid. The enzyme has a pH optimum of 7.5. The double reciprocal plots gave Km values of 4.0 X 10(-5) mol/L for S-adenosylmethionine and 1.8 X 10(-7) mol/L for indolepyruvic acid. A molecular weight of 55000 +/- 5000 has been determined by Sephadex G-150 gel filtration.

The family center--a new form of organization for rural family planning

The history and functions of rural family planning centers in China are reviewed, with a focus on a center in Liaoning Province. "To date, more than 8,500 such centers have been established in 92.2 percent of the rural resident's groups. What the centers do is to give rural residents education and services in family planning, and help them educate themselves.... According to statistics, 99.3 per cent of the babies born in Liaoning Province in 1986 were planned. More than half of the counties and districts and over 90 per cent of the villages reported no unplanned births. The Province now leads the nation in fulfillment of family-planning goals."

Bicarbonate effect on electron flow in a cyanobacteriumSynechocystis PCC 6803

In this communication, evidence is presented from the kinetics of QA (-) decay (where QA is the first plastoquinone electron acceptor of photosystem II) and oxygen evolution for the requirement of bicarbonate in the electron transport in a cyanobacteriumSynechocystis (Pasteur Culture Collection 6803). A large slowing down of QA (-) oxidation, measured from the variable chlorophylla fluorescence after saturating actinic flashes, was observed in the thylakoids ofSynechocystis 6803 depleted of bicarbonate in the presence of 25 mM formate. Qualitatively similar results were obtained with DCMU-treated thylakoids. This shows that bicarbonate depletion inhibits electron transport on the acceptor side of photosystem II between QA and the plastoquinone (PQ) pool in cyanobacteria. Addition of 2.5 mM HCO3 (-) fully reversed the inhibition of electron flow caused by bicarbonate depletion. Two exponential phases of QA (-) decay, a fast one and a slow one, were observed with halftimes of approx. 400 μs (fast) and 26 ms (slow) at pH 6.5. At pH 7.5, these phases were approx. 330 μs (fast) and 21 ms (slow), respectively. The amplitude, but not the halftime, of the fast component decreased by about 70% (pH 6.5) or 50% (pH 7.5); this was accompanied by a concomittant increase in the slow phase. Twenty mM bicarbonate stimulated, by a factor of 4, the Hill reaction in bicarbonate-depletedSynechocystis cells. This effect is independent of CO2 fixation as it was observed even in the presence of an inhibitor DBMIB.

Transient expression of foreign genes in rice, wheat and soybean cells following particle bombardment

The development of an efficient transformation system is a prerequisite for the molecular analysis of gene expression in plants. In crop plants, this development has been hindered by difficulties encountered both in whole plant regeneration from protoplasts and in the general insusceptibility of monocots to Agrobacterium-mediated transformation. We have circumvented these difficulties by transferring foreign genes directly into the intact cells (with cell walls) of three important crop plants including rice, wheat and soybean by a particle bombardment device. Oryza sativa and Triticum monococcum cells were bombarded with accelerated tungsten particles coated with plasmids containing a β-glucuronidase gene as the reporter. Blue transformed cells were detected in an in situ enzyme assay. The number of blue cells was next used as a convenient criterion to study several factors affecting gene transfer efficiency. After optimal conditions were defined, gene transfer into intact cells of O. sativa, T. monococcum and Glycine max was successfully carried out with chloramphenicol acetyltransferase (CAT) gene as the reporter.

Experiences with gossypol as a male pill

In 1981 to 1983 we performed a clinical study with gossypol involving 152 participants, and in 1983 to 1985 we conducted another study of 120 participants. The first study was aimed at confirming gossypol's antifertility efficacy and determining the existence of side effects. The objective of the latter study was to find out whether the addition of a potassium salt supplement or a potassium-sparing agent could alleviate the side effect of hypokalemia. In both studies, the participants took a gossypol pill, 20 mg/day for 60 to 75 days for loading, and 50 mg/wk for maintenance. All participants were followed up for a year. The antifertility efficacy was found to be more than 90%, and the chief side effect was lowered serum potassium. In our 1983 to 1985 study, we concluded that since neither potassium supplementation nor triamterene solved the problem, it is very likely that gossypol is a nephrotoxic agent. With 1 year of gossypol treatment, serum testosterone and serum luteinizing hormone showed no change, whereas serum follicle-stimulating hormone showed some elevation after 6 months. The Shanghai researchers found that in their gossypol users, plasma and urinary beta 2-microglobulin levels were elevated to a certain extent. However, 25 subjects in our 1983 to 1985 study showed no appreciable change. Our volunteers had stopped taking gossypol for more than 1 year. In 1986 we started a third study, which was aimed at finding the lowest antifertility dose to minimize possible renal toxicity.

Clinical trial of gossypol as a male contraceptive drug. Part I. Efficacy study

The main objective of the research is to study the effectiveness and safety of gossypol as a male contraceptive drug. Using a double-blind, randomized, controlled study design, gossypol was found to be an effective male antifertility drug, with no adverse effects on libido nor appetite. In terms of serum potassium levels, there were no statistical differences between gossypol and placebo groups at the end of the loading phase. However, through the ensuing 12 months of maintenance phase, a statistically significant trend toward reduced serum potassium level was evident.