Cytologic screening for esophageal cancer: results from 12,877 subjects from a high-risk population in China

Linxian, China, has one of the highest esophageal-cancer mortality rates in the world. In 1983, esophageal balloon-cytology screening was performed to identify subjects eligible for 2 nutrition-intervention trials in Linxian; 12,877 subjects had cytology slides which were satisfactory for diagnosis. Of the 12,649 subjects with squamous-cell diagnoses, 31% were normal by Chinese cytologic criteria; 38% showed hyperplasia; 21% showed dysplasia 1; 6% showed dysplasia 2; 2% showed near-cancer; and 2% showed cancer. Of the 1,471 subjects with columnar-cell diagnoses, 31% were normal; 44% showed hyperplasia; 16% showed dysplasia 1; 4% showed dysplasia 2; 2% showed near-cancer; and 3% showed cancer. Squamous dysplasia and cancer were more common among females than males, while columnar dysplasia and cancer showed male predominance. The prevalence of dysplasia and cancer of both cell types increased with age. The prevalence of squamous dysplasia was significantly higher than in earlier balloon-cytology screenings in Linxian, probably reflecting changes in cytologic classification.

Effects of amino acid changes in the extracellular domain of the human immunodeficiency virus type 1 gp41 envelope glycoprotein

Changes were introduced into conserved amino acids within the ectodomain of the human immunodeficiency virus type 1 (HIV-1) gp41 transmembrane envelope glycoprotein. The effect of these changes on the structure and function of the HIV-1 envelope glycoproteins was examined. The gp41 glycoprotein contains an amino-terminal fusion peptide (residues 512 to 527) and a disulfide loop near the middle of the extracellular domain (residues 598 to 604). Mutations affecting the hydrophobic sequences between these two regions resulted in two phenotypes. Some changes in amino acids 528 to 562 resulted in a loss of the noncovalent association between gp41 and the gp120 exterior glycoprotein. Amino acid changes in other parts of the gp41 glycoprotein (residues 608 and 628) also resulted in subunit dissociation. Some changes affecting amino acids 568 to 596 resulted in envelope glycoproteins partially or completely defective in mediating membrane fusion. Syncytium formation was more sensitive than virus entry to these changes. Changes in several amino acids from 647 to 675 resulted in higher-than-wild-type syncytium-forming ability. One of these amino acid changes affecting tryptophan 666 resulted in escape from neutralization by an anti-gp41 human monoclonal antibody, 2F5. These results contribute to an understanding of the functional regions of the HIV-1 gp41 ectodomain.

Cytochrome aa3 of Rhodobacter sphaeroides as a model for mitochondrial cytochrome c oxidase. The coxII/coxIII operon codes for structural and assembly proteins homologous to those in yeast

The coxII/coxIII operon of Rhodobacter sphaeroides cytochrome c oxidase has been sequenced and characterized by insertional inactivation/complementation analysis. The organization of the genes in this locus (coxII.orf1.orf3.coxIII) is the same as that of the equivalent operon of Paracoccus denitrificans (ctaC.ctaB.ctaG.ctaE), but unlike that of other bacteria whose cytochrome oxidase genes have been characterized so far. The predicted amino acid sequence homology with eukaryotic oxidases is also higher for Rb. sphaeroides (and P. denitrificans) than for other bacterial versions of the enzyme. The inactivation of coxII results in loss of the characteristic cytochrome oxidase spectrum from membranes of the mutant strain. Full recovery requires introduction into the bacterium of the complete operon containing coxII.orf1.orf3.coxIII; partial complementation yielding a spectrally altered enzyme is achieved with a plasmid containing coxII or coxII.orf1.orf3. These results indicate that the peptides ORF1, ORF3, and COXIII are all required for assembly of native cytochrome c oxidase, suggesting an oxidase-specific assembly or chaperonin function for the ORFs in Rb. sphaeroides similar to that observed for the homologous gene products in yeast, COX10 and COX11.

Binding affinity of bicarbonate and formate in herbicide-resistant D1 mutants of Synechococcus sp. PCC 7942

We examined the effects of mutations at amino acid residues S264 and F255 in the D1 protein on the binding affinity of the stimulatory anion bicarbonate and inhibitory anion formate in Photosystem II (PS II) in Synechococcus sp. PCC 7942. Measurements on the rates of oxygen evolution in the wild type and mutant cells in the presence of different concentrations of formate with a fixed bicarbonate concentration and vice versa, analyzed in terms of an equilibrium activator-inhibitor model, led to the conclusion that the equilibrium dissociation constant for bicarbonate is increased in the mutants, while that of the formate remains unchanged (11±0.5 mM). The hierarchy of the equilibrium dissociation constant for bicarbonate (highest to lowest, ±2 μM) was: D1-F255L/S264A (46 μM)>D1-F255Y/ S264A (31 μM)≈D1-S264A (34 μM)≈D1-F255Y (33 μM)>wild type (25 μM). The data suggest the importance of D1-S264 and D1-F255 in the bicarbonate binding niche. A possible involvement of bicarbonate and these two residues in the protonation of QB (-), the reduced secondary plastoquinone of PS II, in the D1 protein is discussed.

Rapid generation of region-specific genomic clones by chromosome microdissection: isolation of DNA from a region frequently deleted in malignant melanoma

Malignant melanoma is frequently characterized by the deletion of the long arm of chromosome 6 (usually encompassing 6q16-q21). In an effort to saturate this region with DNA markers, microdissection and molecular cloning of DNA from banded human metaphases recent development of a novel chromosome microdissection scheme that omits microchemical manipulation of DNA. Microdissection was targeted on band 6q21. Direct PCR amplification of dissected DNA was first used as a probe in chromosomal in situ hybridization of normal metaphases to confirm the specificity of material excised for cloning. A genomic library of 20,000 clones, which is highly enriched for sequences encompassing 6q21, was then constructed. Clones from this library have been mapped against a human-rodent somatic cell hybrid mapping panel that divides chromosome 6 into seven regions, confirming the localization of probes within the target region. Direct PCR amplification of DNA excised by microdissection greatly simplifies and facilitates this chromosome band-specific cloning strategy. The isolation of microclones from this region of chromosome 6 should assist in establishing a physical map of the melanoma deletion region.

Inhibition of acyl-CoA: cholesterol acyltransferase activity by cyclodepsipeptide antibiotics

The effect was studied of the fungal cyclodepsipeptide antibiotics beauvericin and seven distinct enniatins on acyl-CoA: cholesterol acyltransferase (ACAT) activity. In an enzyme assay using rat liver microsomes, all the compounds were found to inhibit ACAT activity. The drug concentration that caused 50% inhibition (IC50 value) of the enzyme activity was determined to be 3.0 microM for beauvericin, indicating that the compound is one of the most potent ACAT inhibitors of microbial origin. Enniatins exhibited much higher IC50 values of 22 to 110 microM. More hydrophobic enniatins showed more potent inhibitory activity. Furthermore, the ACAT inhibitory activity was evaluated as inhibition of cholesteryl ester formation in a cell assay using J774 macrophages. Calculation of the ratio, CD50 value (the drug concentration causing 50% cell damage)/IC50 value of cholesteryl ester formation, indicated that beauvericin shows the highest specificity. These data indicate that beauvericin is one of the most potent and specific ACAT inhibitors of microbial origin.

Regeneration of herbicide resistant transgenic rice plants following microprojectile-mediated transformation of suspension culture cells

Suspension cells of Oryza sativa L. (rice) were transformed, by microprojectile bombardment, with plasmids carrying the coding region of the Streptomyces hygroscopicus phosphinothricin acetyl transferase (PAT) gene (bar) under the control of either the 5' region of the rice actin 1 gene (Act1) or the cauliflower mosaic virus (CaMV) 35S promoter. Subsequently regenerated plants display detectable PAT activity and are resistant to BASTA(TM), a phosphinothricin (PPT)-based herbicide. DNA gel blot analyses showed that PPT resistant rice plants contain a bar-hybridizing restriction fragment of the expected size. This report shows that expression of the bar gene in transgenic rice plants confers resistance to PPT-based herbicide by suppressing an increase of ammonia in plants after spraying with the herbicide.

Characterization of cis-acting elements regulating transcription from the promoter of a constitutively active rice actin gene

The promoter of the constitutively expressed rice (Oryza sativa) actin 1 gene (Act1) is highly active in transformed rice plants (W. Zhang, D. McElroy, and R. Wu, Plant Cell 3:1150-1160, 1991). A region 834 bp upstream of the Act1 transcription initiation site contains all the regulatory elements necessary for maximal gene expression in transformed rice protoplasts (D. McElroy, W. Zhang, J. Cao, and R. Wu, Plant Cell 2:163-171, 1990). We have constructed a series of Act1 promoter deletions fused to a bacterial beta-glucuronidase reporter sequence (Gus). Transient expression assays in transformed rice protoplasts, as well as transformed maize cells and tissues, identified two distinct cis-acting regulatory elements in the Act1 promoter. A 38-bp poly(dA-dT) region was found to be a positive regulator of Act1 promoter activity. Deletion of the poly(dA-dT) element lowered Gus expression by at least threefold compared with expression produced by the full-length Act1 promoter. By gel retardation and footprinting, we identified a ubiquitous rice protein which specifically recognizes this poly(dA-dT) element in the constitutively active Act1 promoter. A CCCAA pentamer repeat-containing region was found to be a negative regulator of the Act1 promoter in transformed rice protoplasts. Transient expression assays in different maize cells and tissues with use of the Act1 deletion constructs suggested that the CCCAA pentamer repeat region functions in a complex tissue-specific manner. A CCCAA-binding protein was detected only in root extracts.

Automatic antifungal activity analyzing system on the basis of dynamic growth process of a single hypha

A system for the evaluation of antifungal activity of volatile compounds has been developed that is based on dynamic growth of a single hypha. The newly developed system is composed of a reaction vessel under a microscope, automatic stage, charge coupled device (CCD) camera, TV monitor, video tape recorder (VTR), and a microcomputer. A fungus was inoculated in the reaction vessel containing agar medium and then was treated with an antifungal reagent in the gas phase either in batch or flow reaction manner. The apex of a growing hypha displayed on a TV monitor was followed automatically. From the ratio of the growth rate under exposure of a reagent (UEXPO) to the growth rate before the exposure (UPRE), the antifungal activity was expressed quantitatively.

Is bicarbonate in Photosystem II the equivalent of the glutamate ligand to the iron atom in bacterial reaction centers?

Photosystem II of oxygen-evolving organisms exhibits a bicarbonate-reversible formate effect on electron transfer between the primary and secondary acceptor quinones, QA and QB. This effect is absent in the otherwise similar electron acceptor complex of purple bacteria, e.g., Rhodobacter sphaeroides. This distinction has led to the suggestion that the iron atom of the acceptor quinone complex in PS II might lack the fifth and sixth ligands provided in the bacterial reaction center (RC) by a glutamate residue at position 234 of the M-subunit in Rb. sphaeroides RCs (M232 in Rps. viridis). By site-directed mutagenesis we have altered GluM234 in RCs from Rb. sphaeroides, replacing it with valine, glutamine and glycine to form mutants M234EV, M234EQ and M234EG, respectively. These mutants grew competently under phototrophic conditions and were tested for the formate-bicarbonate effect. In chromatophores there were no detectable differences between wild type (Wt) and mutant M234EV with respect to cytochrome b-561 reduction following a flash, and no effect of bicarbonate depletion (by incubation with formate). In isolated RCs, several electron transfer activities were essentially unchanged in Wt and M234EV, M234EQ and M234EG mutants, and no formate-bicarbonate effect was observed on: (a) the fast or slow phases of recovery of the oxidized primary donor (P+) in the absence of exogenous donor, i.e., the recombination of P+Q-A or P+Q-B, respectively; (b) the kinetics of electron transfer from Q-A to QB; or (c) the flash dependent oscillations of semiquinone formation in the presence of donor to P+ (QB turnover). The absence of a formate-bicarbonate effect in these mutants suggests that GluM234 is not responsible for the absence of the formate-bicarbonate effect in Wt bacterial RCs, or at least that other factors must be taken into account. The mutant RCs were also examined for the fast primary electron transfer along the active (A-)branch of the pigment chain, leading to reduction of QA. The kinetics were resolved to reveal the reduction of the monomer bacteriochlorophyll (tau = 3.5 ps), followed by reduction of the bacteriopheophytin (tau = 0.9 ps). Both steps were essentially unaltered from the wild type. However, the rate of reduction of QA was slowed by a factor of 2 (tau = 410 +/- 30 and 47 +/- 30 ps for M234EQ and M234EV, respectively, compared to 220 ps in the wild type).(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation and interaction of multiple protein factors with the proximal promoter regions of a rice high pI alpha-amylase gene

The alpha-amylase gene is known to be regulated by the plant hormone gibberellin (GA) in cereal aleurone cells. The accumulation of the mRNA corresponding to a rice high pI alpha-amylase gene, OSamy-c, was stimulated 20-fold by exogenous GA3 in half-seeds lacking embryos. Regulatory regions in the promoter of this high pI sub-family were analyzed. The OSamy-c 5' flanking sequence, spanning positions -231 to +29, was fused upstream of the beta-glucuronidase (GUS) gene coding region. The delivery of this plasmid into rice aleurone cells by the biolistic method resulted in a GA-stimulated synthesis of GUS. Gel retardation assays were performed to study protein-DNA interactions between putative regulatory sequences of OSamy-c and partially purified rice seed extracts. We identified multiple seed-specific protein factors that bind to proximal regions of the OSamy-c promoter between positions -231 and -162. Five different proteins were distinguished based on competitive binding studies. Three protein binding regions were located by footprinting analyses, one of which is located in the conserved sequence also found upstream of other GA-inducible genes. Two protein factors in rice aleurone cells that interact with the putative regulatory sequence do not require GA induction.

Optical constants of very thin gold films in the soft x-ray region

The optical constants, delta = 1 - n and k, of very thin gold films have been determined from the reflectance data obtained in the soft x-ray region of 60-900 eV. The gold films were prepared to various thicknesses, d = 49 - 270 A, by ion beam sputtering (IBS) and electron beam evaporation (EB). A plane parallel slab model with due considerations for the surface and the interface roughness was employed to analyze the reflectance data by least-squares curve fitting. The optical constants determined for the IBS samples definitely show their dependence on the film thickness. It is also found that delta of the 201-A thick IBS film is smaller by 10% than that of the EB film of 212 A thick.

The gene encoding cytochrome c oxidase subunit II from Rhodobacter sphaeroides; comparison of the deduced amino acid sequence with sequences of corresponding peptides from other species

The gene (coxII) encoding subunit II of Rhodobacter sphaeroides cytochrome c oxidase (cytochrome aa3) has been isolated by screening a genomic DNA library in phage lambda with a probe derived from coxII of Paracoccus denitrificans. A 2-kb fragment containing coxII DNA was subcloned into the phage M13mp18 and the sequence determined. The 2-kb insert contains the entire coding region for coxII gene, including the ATG start codon and a TGA stop codon. The deduced amino acid (aa) sequence of subunit II of R. sphaeroides shows regions of substantial homology to the corresponding subunit of the bovine mitochondrial oxidase (63% overall) and P. denitrificans oxidase (68% overall). The postulated redox-active copper ion (CuA) binding site involving two Cys and two His residues (as well as an alternative Met residue) is conserved among these species, along with four invariant acidic aa residues (two Asp and two Glu) that may be involved in interactions with cytochrome c, and a region of aromatic residues (Tyr-Gln-Trp-Tyr-Trp-Gly-Tyr-Glu-Tyr) which is postulated to play a role in electron transfer. Hydropathy profile analysis suggests that while the bovine COXII secondary structure contains two transmembrane helices, the R. sphaeroides subunit II has a third such helix that may function as part of a signal sequence, as suggested for P. denitrificans.

[Isolation and characteristics of Borrelia burgdorferi from Ixodes persulcatus]

We reported the detailed characteristics of Lyme disease spirochetes (Borrelia burgdorferi), strain H7, isolated from Ixodes persulcatus in Heilongjiang. Cells of strain H7 were 9.8--26.5 microns long and 0.13--0.35 microns wide. There were 1--11 waves with a wavelength of 1.2--3.0 microns and an amplitude of 0.59--1.13 microns. Direction of spires was left. Seven flagella were inserted subterminally at each end of the cell and ends were pointed. 31 degrees C was the optimum cultural temperature in vitro. The major constitutional and antigenic proteins were 21k, 32k and 34k proteins. H7 could react on the patient sera of Xinjiang and Heilongjiang with IFA and western blot. These findings demonstrated that strain H7 belonged to species Borrelia burgdorferi, but was a new "subtype" which differed from the strains isolated from other areas and vectors.

Purpactins, new inhibitors of acyl-CoA:cholesterol acyltransferase produced by Penicillium purpurogenum. III. Chemical modification of purpactin A

Acylated derivatives of the C-1' and/or C-11 hydroxy group(s) of penicillide were synthesized and their inhibitory activity against acyl-CoA:cholesterol acyltransferase (ACAT) was studied. Introduction of long acyl group into either or both hydroxy residue(s) decreased the inhibitory activity. A small acyl moiety such as acetyl or n-butyryl at the C-1' hydroxy group is responsible for potent inhibitory activity against ACAT. The 1'-O-acetyl-11-O-tetrahydropyranyl derivative (11-O-2''-tetrahydropyranylpurpactin A) showed high selectivity (cytotoxic dose vs. effective dose) in a cell assay using J774 macrophages.

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.