Purpactins, new inhibitors of acyl-CoA:cholesterol acyltransferase produced by Penicillium purpurogenum. I. Production, isolation and physico-chemical and biological properties

Penicillium purpurogenum FO-608, a soil isolate, was found to produce a series of new inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT). Three active compounds, designated purpactins, A, B and C, were isolated from the fermentation broth of the producing strain by solvent extraction, silica gel column chromatography and HPLC. Purpactins inhibit ACAT activity in an enzyme assay system using rat liver microsomes with IC50 values of 121 approximately 126 microM. Purpactin A also inhibited cholesterol ester formation in J 774 macrophages, indicating the inhibition of ACAT activity in the living cells by purpactin A.

Purpactins, new inhibitors of acyl-CoA:cholesterol acyltransferase produced by Penicillium purpurogenum. II. Structure elucidation of purpactins A, B and C

The structure of purpactins, novel acyl-CoA:cholesterol acyltransferase (ACAT) inhibitors, was determined by spectroscopic analyses. Purpactin A was deduced to be 3-1'-acetoxy-11-hydroxy-4-methoxy-9-methyl-3'-methylbutyl-5H, 7H-dibenzo[b,g]-1,5-dioxocin-5-one, purpactin B was 5-1''-acetoxy-6'-hydroxymethyl-4-methoxy-4'-methyl-3''-methylbutyl-spiro [benzofuran-2,1'-cyclohexa-3',5'-diene]-2',3(2H)-dione and purpactin C was 5-1''-acetoxy-6'-formyl-4-methoxy-4'-methyl-3''-methylbutyl-spiro [benzofuran-2,1'-cyclohexa-3',5'-diene]-2',3(2H)-dione. Purpactin A was attributed to 1'-O-acetylpenicillide.

Low density lipoprotein activates monocytes to express tumor necrosis factor

We analyzed the effect of acetylated low density lipoprotein (aLDL) incubation on tumor necrosis factor (TNF) mRNA and protein expression in isolated resting human monocytes in serum free DMEM. TNF mRNA expression was about one third that of PMA and was dose dependent. The maximum stimulatory effect on TNF mRNA was at 250 micrograms/ml, while 500 micrograms/ml induced downregulation. The maximum stimulatory effect occurred at 6 hours, and by 24 hours TNF mRNA expression returned to the resting state. Acetyl LDL also induced the expression of immunoreactive TNF, reaching a sevenfold maximum above control at 12 hours following a 6 hour exposure period. The results suggest that aLDL is a potent stimulator of TNF expression in resting monocytes. This mechanism may be operational in atheroma evolution.

Purification of highly active oxygen-evolving photosystem II from Chlamydomonas reinhardtii

A method is described for the isolation and purification of active oxygen-evolving photosystem II (PS II) membranes from the green alga Chlamydomonas reinhardtii. The isolation procedure is a modification of methods evolved for spinach (Berthold et al. 1981). The purity and integrity of the PS II preparations have been assesssed on the bases of the polypeptide pattern in SDS-PAGE, the rate of oxygen evolution, the EPR multiline signal of the S2 state, the room temperature chlorophyll a fluorescence yield, the 77 K emission spectra, and the P700 EPR signal at 300 K. These data show that the PS II characteristics are increased by a factor of two in PS II preparations as compared to thylakoid samples, and the PS I concentration is reduced by approximately a factor ten compared to that in thylakoids.

Tumor necrosis factor gene expression in human vascular intimal smooth muscle cells detected by in situ hybridization

We used immunohistochemistry to detect tumor necrosis factor (TNF) and in situ hybridization to detect TNF messenger RNA (mRNA) in the intimal mesenchymal-appearing cells and in the medial smooth muscle cells of human atherosclerotic arteries. Medial smooth muscle cells showed localization of immunoreactive TNF on the cell surface and did not express TNF mRNA. Conversely, in intimal mesenchymal-appearing cells, TNF was localized in the cytoplasm and TNF mRNA was expressed by in situ hybridization. Thus 89% of intimal cells were immunohistochemically positive for TNF, 96% of them were positive by in situ hybridization, and 76% were positive for the smooth muscle cell marker, HHF35. Our results suggest that intimal mesenchymal-appearing cells are mostly, but not exclusively, derived from smooth muscle cells. These cells express TNF, whereas the medial smooth muscle cells in the atherosclerotic human arteries do not. The expression of TNF by these mesenchymal-appearing cells may have implications regarding the evolution of the atherosclerotic plaque.

[Inhibition of growth and metastases of lung carcinoma in C57BL/6 mice by Corynebacterium parvum and its antitumor mechanism]

Cocrynebacterium parvum (CP) was injected around the tumor and tumor cells were inoculated subcutaneously with activated peritoneal macrophages. The effects on the growth and metastases of Lewis lung carcinoma in C57BL/6 mice were observed. Experimental results indicated that CP had significant inhibitory effect on the tumor growth and lung metastases. The cytotoxic effects of activated peritoneal macrophages in mice on target tumor cells (L5178Y) in vitro were studied with the technique of 3H-TdR assay. The proliferation of tumor cells was markedly inhibited by the activated peritoneal macrophages of CP. Experiments showed that the antitumor mechanism of CP was the mediation via activated cytotoxic macrophages. These results indicated that CP is an effective immunostimulant. These findings will provide a scientific basis for the clinical treatment of the primary and metastatic lung carcinoma.

Chlorophyll a fluorescence transient as an indicator of active and inactive Photosystem II in thylakoid membranes

Upon illumination, a dark-adapted photosynthetic sample shows time-dependent changes in chlorophyll (Chl) a fluorescence yield, known as the Kautsky phenomenon or the OIDPS transient. Based on the differential effects of electron acceptors such as 2,5-dimethyl-p-benzoquinone (DMQ) and 2,6-dichloro-p-benzoquinone (DCBQ) on Chl a fluorescence transients of spinach thylakoids, we suggest that the OID phase reflects the reduction of the electron acceptor QA to QA- in the inactive PS II (see Graan, T. and Ort, D. (1986) Diochim. Biophys. Acta 852, 320-330). In spinach thylakoids, heat-induced increase of the Chl a fluorescence yield is also differentially sensitive to the addition of DMQ and DCBQ suggesting that this increase is mainly on the 'I' level, and thus heating is suggested to convert active PS II to inactive PS II centers. The kinetics of decay of QA-, calculated from variable Chl a fluorescence, was analyzed into three exponential components (365-395 microseconds; 6-7 ms; and 1.4-1.7 s). In heated samples, the decay rate of variable Chl a fluorescence is slower than the normal back-reaction rate; there is a preponderance of the slow component that may be due, partly, to the active centers undergoing slow back reaction between QA- and the S2 state of the oxygen-evolving complex.

Detection and localization of tumor necrosis factor in human atheroma

Tumor necrosis factor (TNF) is a secretory product of normal macrophages that can cause cell necrosis, new blood vessel formation and thrombosis. These are also 3 characteristic features of the progression of stable atheroma to endothelial disruption. Accordingly, an immunohistochemical method was developed to detect TNF in human tissue. Using this method TNF positivity was demonstrated in 57 of 65 (88%) of tissue sections classified as atherosclerotic and in 5 of 11 (45%) sections classified as minimally atherosclerotic. TNF was absent in 6 sections classified as normal. TNF positivity was found not only in the cytoplasm of macrophages, but also in the cytoplasm and attached to the cell membrane of smooth muscle cells and endothelial cells of the human atheroma. Because TNF is known to cause new vessel formation, hemorrhagic necrosis and increased thrombogenicity, it may play a role in the evolution of uncomplicated to complex atheroma.

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.