Effect of herba artemisiae scopariae on cytogenetic damage induced by aflatoxin B1

It was found that the per mill rate of micronucleus of marrow cells in mice induced by AFB1 decreased with the increasing dosage of Herba Artemisiae Scopariae, and that there were dosage-effect relations in the lowering of percentage of chromosomal aberration induced by AFB1 and in the inhibition effect on some sister chromatid exchanges per cell.

Identification of a minimal hydrophobic domain in the herpes simplex virus type 1 scaffolding protein which is required for interaction with the major capsid protein

Recent biochemical and genetic studies have demonstrated that an essential step of the herpes simplex virus type 1 capsid assembly pathway involves the interaction of the major capsid protein (VP5) with either the C terminus of the scaffolding protein (VP22a, ICP35) or that of the protease (Pra, product of UL26). To better understand the nature of the interaction and to further map the sequence motif, we expressed the C-terminal 30-amino-acid peptide of ICP35 in Escherichia coli as a glutathione S-transferase fusion protein (GST/CT). Purified GST/CT fusion proteins were then incubated with 35S-labeled herpes simplex virus type 1-infected cell lysates containing VP5. The interaction between GST/CT and VP5 was determined by coprecipitation of the two proteins with glutathione Sepharose beads. Our results revealed that the GST/CT fusion protein specifically interacts with VP5, suggesting that the C-terminal domain alone is sufficient for interaction with VP5. Deletion analysis of the GST/CT binding domain mapped the interaction to a minimal 12-amino-acid motif. Substitution mutations further revealed that the replacement of hydrophobic residues with charged residues in the core region of the motif abolished the interaction, suggesting that the interaction is a hydrophobic one. A chaotropic detergent, 0.1% Nonidet P-40, also abolished the interaction, further supporting the hydrophobic nature of the interaction. Computer analysis predicted that the minimal binding motif could form a strong alpha-helix structure. Most interestingly, the alpha-helix model maximizes the hydropathicity of the minimal domain so that all of the hydrophobic residues are centered around a Phe residue on one side of the alpha-helix. Mutation analysis revealed that the Phe residue is absolutely critical for the binding, since changes to Ala, Tyr, or Trp abrogated the interaction. Finally, in a peptide competition experiment, the C-terminal 25-amino-acid peptide, as well as a minimal peptide derived from the binding motif, competed with GST/CT for interaction with VP5. In addition, a cyclic analog of the minimal peptide which is designed to stabilize an alpha-helical structure competed more efficiently than the minimal peptide. The evidence suggests that the C-terminal end of ICP35 forms an alpha-helical secondary structure, which may bind specifically to a hydrophobic pocket in VP5.

[Pharmacokinetics of ciprofloxacin injection in healthy volunteers]

The results of pharmacokinetic study of intravenous infusion ciprofloxacin in normal male volunteers were presented. Serum and urine concentrations of ciprofloxacin were determined by high performance liquid chromatography. The single dose 200 mg iv concentration-time curve fitted to two-compartment open model in eight volunteers. Its main pharmacokinetic parameters were: C0 4.61 +/- 1.64 mg/L, t1/2 beta 3.86 +/- 0.67 h and AUC 7.06 +/- 1.21 mg/L.h. The urinary recovery rate of ciprofloxacin over 12 h after dosing was 60.85%.

Overexpression of [delta]-Pyrroline-5-Carboxylate Synthetase Increases Proline Production and Confers Osmotolerance in Transgenic Plants

Proline (Pro) accumulation has been correlated with tolerance to drought and salinity stresses in plants. Therefore, overproduction of Pro in plants may lead to increased tolerance against these abiotic stresses. To test this possibility, we overexpressed in tobacco the mothbean [delta]-pyrroline-5-carboxylate synthetase, a bifunctional enzyme able to catalyze the conversion of glutamate to [delta]-pyrroline-5-carboxylate, which is then reduced to Pro. The transgenic plants produced a high level of the enzyme and synthesized 10- to 18-fold more Pro than control plants. These results suggest that activity of the first enzyme of the pathway is the rate-limiting factor in Pro synthesis. Exogenous supply of nitrogen further enhanced Pro production. The osmotic potentials of leaf sap from transgenic plants were less decreased under water-stress conditions compared to those of control plants. Overproduction of Pro also enhanced root biomass and flower development in transgenic plants under drought-stress conditions. These data demonstrated that Pro acts as an osmoprotectant and that overproduction of Pro results in the increased tolerance to osmotic stress in plants.

Overexpression of [delta]-Pyrroline-5-Carboxylate Synthetase Increases Proline Production and Confers Osmotolerance in Transgenic Plants

Proline (Pro) accumulation has been correlated with tolerance to drought and salinity stresses in plants. Therefore, overproduction of Pro in plants may lead to increased tolerance against these abiotic stresses. To test this possibility, we overexpressed in tobacco the mothbean [delta]-pyrroline-5-carboxylate synthetase, a bifunctional enzyme able to catalyze the conversion of glutamate to [delta]-pyrroline-5-carboxylate, which is then reduced to Pro. The transgenic plants produced a high level of the enzyme and synthesized 10- to 18-fold more Pro than control plants. These results suggest that activity of the first enzyme of the pathway is the rate-limiting factor in Pro synthesis. Exogenous supply of nitrogen further enhanced Pro production. The osmotic potentials of leaf sap from transgenic plants were less decreased under water-stress conditions compared to those of control plants. Overproduction of Pro also enhanced root biomass and flower development in transgenic plants under drought-stress conditions. These data demonstrated that Pro acts as an osmoprotectant and that overproduction of Pro results in the increased tolerance to osmotic stress in plants.

Schistosoma mansoni: cloning and characterization of a gene encoding cytosolic Cu/Zn superoxide dismutase

Two forms of Cu/Zn superoxide dismutase (SOD) have been identified in Schistosoma mansoni, signal peptide-containing SOD (SP-SOD, Simurda et al., 1988, Exp. Parasitol. 67, 73-84) and cytosolic SOD (CT-SOD, Hong et al., 1992, Exp. Parasitol. 75, 308-322). The SP-SOD gene has been previously characterized. We report the isolation and characterization of the gene encoding CT-SOD. A cDNA clone of CT-SOD was radiolabeled and used to screen an EMBL3 genomic library. Of 100,000 plaques, 1 hybridizing phage contained an insert of 14.6 kb. The CT-SOD gene spans 8.5 kb of chromosomal DNA and possesses three exons (150, 285, and 234 bp, respectively) and two introns (4.9 and 2.7 kb, respectively) which interrupt the coding region. Separate copies of the gene as determined by restriction fragment patterns on Southern blots are found on two YAC clones. Using YAC clones that contain the CT-SOD gene, fluorescence in situ hybridization on chromosomes identified a copy of the gene located on the middle region of chromosome 1 and another copy localized to the middle region of the long arm of chromosome 3. Primer extension and nuclease protection assay performed on total RNA define the transcription initiation site and allow the identification of potential cis-acting sequences, such as a CAAT box and a hexanucleotide GCCCGG. Comparison of this gene with Cu/Zn SOD genes from Drosophila, humans, and mice identifies conserved exons that represent functional domains in the SOD protein.

[Pharmacokinetics and bioavailability study on acetaminophen oral drop in healthy volunteers]

The concentrations of acetaminophen in human plasma were determined by RP-HPLC after administration of a single oral dose of 1000 mg acetaminophen oral drop or tablet to eight normal male volunteers in a crossover study. The concentration vs time curves of acetaminophen all fitted the two compartment model. The Cmax in oral drop and tablet were 11.23 +/- 0.93 and 8.79 +/- 0.93mg/L, respectively; Tmax were 0.86 +/- 0.08 and 1.48 +/- 0.39h; T1/2 beta 3.03 +/- 0.79 and 2.51 +/- 1.10 h; AUC 42.35 +/- 6.20 and 40.60 +/- 6.79mg/L.h. When AUC in tablet was 100%, the relative bioavailability of acetaminophen oral drop was 105.58%. The results showed that the oral drop and tablet are bioequivalent.

A phosphatidylinositol 3-kinase is induced during soybean nodule organogenesis and is associated with membrane proliferation

Phosphatidylinositol 3-kinase (PI3K) is an important component of various receptor tyrosine kinase complexes in mammalian cells and a key enzyme required for cell division and vacuolar protein sorting in yeast. To our knowledge, this enzyme has not been characterized in plants. We report the cloning and characterization of soybean PI3K cDNAs and present evidence for the induction of a distinctive form of this enzyme specific to nodule organogenesis. Expression of the root form of PI3K is repressed during nodule organogenesis and is reinduced in mature nodules. Primer-extension results showed that the gene encoding the nodule form of PI3K is highly expressed in young (12-15 day old) root nodules in parallel with membrane proliferation but is repressed in mature nodules. The root form of the PI3K cDNA (SPI3K-5) encodes a peptide of 814 amino acids and the nodule form (SPI3K-1) encodes a peptide of 812 amino acids. Both cDNAs share 98% sequence identity in the coding region but differ in the noncoding regions. The polypeptides encoded by soybean PI3K cDNAs show significant sequence homology (50-60% similarity and 20-40% identity) to both PI3Ks and phosphatidylinositol 4-kinases from mammalian and yeast cells. Escherichia coli expressed soybean PI3K phosphorylated phosphatidylinositol specifically at the D-3 position of the inositol ring to generate phosphatidylinositol 3-phosphate. The temporal increase of a specific PI3K activity during membrane proliferation in young nodules suggests that PI3K plays a pivotal role in development of the peribacteroid membrane forming a subcellular compartment.

Analysis of beta-glucans and chitin in a Saccharomyces cerevisiae cell wall mutant using high-performance liquid chromatography

We have previously shown that mutations in the yeast KNR4 gene resulted in pleiotropic cell wall defects, including resistance to killer 9 toxin, elevated osmotic sensitivity to SDS and increased resistance to zymolyase, a (1-->3)-beta-glucanase. In this report, we further demonstrated that knr4 mutant cells were more permeable to a chromogenic substrate, X-GAL, suggesting that the mutant cell walls were leakier to certain non-permeable molecules. To determine if these defects resulted from structural changes in the cell walls, we analysed the alkali-insoluble cell wall components using HPLC assays developed for this purpose. Comparative analysis using four isogenic strains from a 'knr4 disrupted' tetrad demonstrated that mutant cell walls contained much less (1-->3)-beta-glucan and (1-->6)-beta-glucan; however, the level of chitin, a minor cell wall component, was found to be five times higher in the mutant strains compared to the wild-type strains. The data suggested that the knr4 mutant cell walls were dramatically weakened, which may explain the pleiotropic cell wall defects.

Nodulin-24 follows a novel pathway for integration into the peribacteroid membrane in soybean root nodules

Nodulin-24 is a nodule-specific protein of the peribacteroid membrane (PBM) in soybean. It has an apparent molecular mass of 33 kDa while its full-length cDNA encodes a polypeptide of only 24 kDa. In vitro transcription of nodulin-24 cDNA followed by translation resulted in a peptide translocated into microsomal membranes with cleavage of a signal sequence. The cleavage site of the signal sequence in nodulin-24 was determined to be between Ala (A25) and Arg (R26) by microsequencing of the [3H]leucine-labeled processed peptide. Fusion of the signal sequence of nodulin-24 with the beta-glucuronidase peptide prevented co-translational cleavage of the signal sequence although the translocation of the fused protein into microsomes occurred co-translationally. Trypsin treatment of membrane-translocated nodulin-24 did not result in any alteration in size suggesting that the newly synthesized peptide is fully protected in the membrane vesicle. Fusion of nodulin-24 with beta-glucuronidase also showed no change in size following trypsin treatment, suggesting that nodulin-24 has no membrane-spanning region. In addition, in vitro synthesized nodulin-24 was present in the supernatant fraction after sonication of microsomal membranes. Mature nodulin-24, on the other hand, is not solubilized from PBM by sodium carbonate (pH 11) or EGTA and is soluble only in detergent. These data suggest that nodulin-24 is synthesized as a lumenal protein in the endoplasmic reticulum and post-translationally attached to the membranes en route to the PBM. This processing results in a significant increase in the apparent molecular mass of nodulin-24 which may be due to the attachment of membrane lipids as this protein shares characteristics with membrane lipoproteins of many pathogenic bacteria.

Size of the zinc pools that exchange rapidly with plasma zinc in humans: alternative techniques for measuring and relation to dietary zinc intake

A relatively simple technique was used to estimate the size of the combined pools of zinc with which plasma zinc exchanges within 2 d (EZP). EZP size was determined from the amount of isotope introduced into the plasma and the coefficient of the simple exponential decay function fitting enrichment data between d 3 and 9 after isotope administration. Using data from 11 healthy adults, comparisons were made of EZP size estimations using oral and intravenous isotopes (r = 0.93 using urine) and urine and plasma enrichment (r = 0.85 for intravenous). EZP size estimations from urine and plasma enrichment following intravenous isotope administration were 2.35 +/- 0.84 and 2.83 +/- 0.86 mmol, respectively (mean +/- SD, P < 0.01). EZP size correlated with habitual dietary zinc intake (partial r = 0.74, P < 0.02). Cumulative declines in EZP size in two healthy adults after 3 wk of consuming a moderately zinc-restricted diet followed by 1 wk of severe zinc restriction were 26 and 32%. These results indicated that EZP size is dependent on dietary intake. We conclude that this technique is adequate to demonstrate EZP differences that are of nutritional and physiological interest. EZP size estimates can be obtained using orally or intravenously administered isotope and using plasma or urine enrichment data.

Cloning and characterization of KNR4, a yeast gene involved in (1,3)-beta-glucan synthesis

k9 killer toxin from Hansenula mrakii was used to select a number of resistant mutants from Saccharomyces cerevisiae. Preliminary biochemical and genetic studies showed that some of them acquired structural defects in the cell wall. One of these mutants, the knr4-1 mutant, displays a number of cell wall defects, including osmotic sensitivity; sensitivity to cercosporamide, a known antifungal agent; and resistance to Zymolyase, a (1,3)-beta-glucanase. We report here the isolation and analysis of the KNR4 gene. DNA sequence analysis revealed an uninterrupted open reading frame which contains five potential start codons. The longest coding template encodes a protein of 505 amino acids with a calculated molecular mass of 57,044 Da. A data base search revealed 100% identity with a nuclear protein, SMI1p. Disruption of the KNR4 locus does not result in cell death; however, it leads to reduced levels of both (1,3)-beta-glucan synthase activity and (1,3)-beta-glucan content in the cell wall. The gene was mapped to the right arm of chromosome VII.

Schistosoma mansoni: a Cu/Zn superoxide dismutase is glycosylated when expressed in mammalian cells and localizes to a subtegumental region in adult schistosomes

We previously isolated a gene from Schistosoma mansoni with the capacity to encode a 20-kDa polypeptide that had homology to Cu/Zn superoxide dismutase from 19 other species. The predicted protein sequence contained a hydrophobic N-terminus as well as a site for N-linked glycosylation, suggesting that the protein was a secreted or membrane-associated form of the enzyme. To study this protein further, we first expressed it in a prokaryotic system and used the gene product to make both monoclonal and polyclonal antibodies. We then expressed the protein in CMT3 cells, a monkey kidney cell line, to investigate possible post-translational modifications. Our results demonstrated that the schistosomal protein expressed in CMT3 cells migrated on an SDS-polyacrylamide gel as multiple glycosylated species with molecular masses of 20, 22, and 23 kDa. Glycosylation was inhibited by tunicamycin, resulting in the expression of an unglycosylated product which migrated with a molecular mass of 18 kDa. The CMT3-cell expressed protein eluted from a gel filtration column with a molecular mass larger than 200 kDa, suggesting that it was membrane-associated or bound to a high-molecular-weight component. The product could not be detected in the medium of the CMT3 cell culture and apparently was not secreted. Comparison between the protein expressed in CMT3 cells and that found in adult schistosomes showed that the parasite-derived gene product was also heterogeneous but had different molecular masses (20, 23, and 25 kDa). The protein was localized in frozen sections of adult worms to the subtegumental area as detected by indirect immunofluorescence using monoclonal antibodies. Since the protein was glycosylated but not secreted we suggest it be called signal peptide-containing superoxide dismutase.

Two functional soybean genes encoding p34cdc2 protein kinases are regulated by different plant developmental pathways

We have isolated two cDNA clones (cdc2-S5 and cdc2-S6) encoding p34cdc2 protein kinases, homologs of yeast cdc2/CDC28 genes, from a soybean nodule cDNA library. The two sequences share 90% sequence homology in the coding regions. The 5' and 3' noncoding regions are distinct from each other, however, indicating that at least two genes encode p34cdc2 protein kinases in soybean. Both sequences can rescue the cdc28 mutation in Saccharomyces cerevisiae but rescue it with different efficiency. Genomic Southern analysis showed the existence of two copies for each of these genes, which are not closely linked and are nonallelic. The relative expression level of the two soybean p34cdc2 genes varies in different tissues. Expression of cdc2-S5 is higher in roots and root nodules, whereas cdc2-S6 is more actively expressed in aerial tissues, indicating that regulation of these two p34cdc2 genes is coupled with plant developmental pathways. Expression of cdc2-S5 is, furthermore, enhanced after Rhizobium infection, whereas cdc2-S6 fails to respond, suggesting that cdc2-S5 plays a role in nodule initiation and organogenesis. This latter gene preferentially responds to auxin (alpha-naphthaleneacetic acid) treatment, indicating that phytohormones may be involved in the control of cell division mediated by Rhizobium infection. Thus, different p34cdc2 protein kinases may control cell division in different tissues in a multicellular organism and respond to different signals--e.g., phytohormones.

Schistosoma mansoni: cloning of a complementary DNA encoding a cytosolic Cu/Zn superoxide dismutase and high-yield expression of the enzymatically active gene product in Escherichia coli

We recently purified a 16-kDa cytosolic Cu/Zn superoxide dismutase (CT Cu/Zn-SOD) from Schistosoma mansoni, a human parasite. Three peptide sequences were obtained, one from the unblocked N-terminal and two from internal peptides which were generated by digestions with trypsin and cyanogen bromide. These sequences were aligned to the corresponding sequences of 19 cytosolic Cu/Zn-SODs from various species. Degenerate oligonucleotides were then designed according to the sequence and the position of each peptide. The oligonucleotides were used to amplify a complete cDNA using the polymerase chain reaction with either adult schistosome total RNA or a cercariae lambda gt11 phage cDNA library as the template. The protein encoded by the cDNA has 153 amino acids with a calculated molecular weight of 15,693. It also has 60-65% homology to 19 cytosolic Cu/Zn-SOD from various species. All of the copper/zinc binding sites and SOD activity sites are conserved. Computer analysis predicts that the Cu/Zn-SOD has a pI value of 6.6, which is very close to the experimental results of IEF analysis (6.0 and 6.3). The entire coding sequence from the cDNA was cloned into a bacterial alkaline phosphatase cytosolic expression vector and a large amount of soluble product was expressed and purified to homogeneity. We compared the bacterially expressed Cu/Zn-SOD with the native enzyme derived from schistosomes and found that they are identical by the following criteria: (1) They focus at the same positions on IEF gels; (2) they form dimers in solution as measured by gel filtration; (3) they have the same unblocked N-terminal sequence; (4) they both are enzymatically active with comparable specific activities. The specific activity of the bacterially derived enzyme was increased somewhat (approximately 10%) by incubation with copper and zinc ions.

Identification and purification of a second form of Cu/Zn superoxide dismutase from Schistosoma mansoni

Our laboratories previously isolated a putative extracellular or membrane-associated Cu/Zn superoxide dismutase (Cu/Zn-SOD) gene, designated a signal peptide-containing (SP) Cu/Zn-SOD, from Schistosoma mansoni. SOD activity was thus investigated throughout the life cycle of S. mansoni and found in all stages: eggs, miracidia, cercariae, schistosomula, lung-stage worms, and adult worms. The adult worms had the highest SOD activity (53 +/- 9 nitrite units), which was five times higher than that of eggs or miracidia and twice as high as that of 3-h-old mechanically transformed schistosomula. Cu/Zn-SOD constituted over 95% of the total SOD activity found in S. mansoni, compared with that of Mn-SOD. Most of Cu/Zn-SOD specific activity was associated with a detergent-extractable fraction of the parasite. Isoelectric focusing gel electrophoresis analysis revealed that there were four major pI variants of Cu/Zn-SOD present in the adult worms. Only two of these Cu/Zn-SOD pI variants were present in the 3-h-old mechanically transformed schistosomula. Fast protein liquid chromatography gel filtration fractionation of adult parasite extract was carried out to correlate the SP Cu/Zn-SOD with the SOD activity by using anti-SP Cu/Zn-SOD monoclonal antibodies, which separated the immunoreactive gene product and the SOD activity into different fractions. Quantitative tissue fractionation also revealed a discordant distribution of the gene product compared with that of Cu/Zn-SOD activity. These results indicated the existence of another Cu/Zn-SOD(s) in the parasite. Purification of the Cu/Zn-SOD activity from the adult worms showed that it represented the two lower-pI variants found in both adult worms and 3-h-old schistosomula. Peptide sequence analysis of the purified Cu/Zn-SOD confirmed that there is a second form of Cu/Zn-SOD in the parasite.

Interim report of Sino-Monica-Beijing for the years 1985-1989

Interim results of Sino-Monica-Beijing for the 5 year period 1985-1989 are reported. The cardiovascular disease (CVD) risk factors increased between the surveys carried out in 1984-1985 and 1988-1989, especially blood cholesterol and body mass index.

Subcellular location of delta-pyrroline-5-carboxylate reductase in root/nodule and leaf of soybean

The expression of Delta(1)-pyrroline-5-carboxylate reductase (P5CR) gene was found to be higher in soybean root nodules than in leaves and roots, and its expression in roots appeared to be osmoregulated (AJ Delauney, DPS Verma [1990] Mol Gen Genet 221: 299-305). P5CR was purified to homogeneity as a monomeric protein of 29 kilodaltons by overexpression of a soybean P5CR cDNA clone in Escherichia coli. The pH optimum of the purified P5CR was altered by increasing the salt concentration, and maximum enzyme activity was attainable at a lower pH under high salt (0.2-1 molar NaCl). Kinetic studies of the purified enzyme suggested that nicotinamide adenine dinucleotide phosphate(+) inhibited P5CR activity, whereas nicotinamide adenine dinucleotide(+) did not. Subcellular fractionation and antibodies raised against purified soybean P5CR were used to investigate location of the enzyme in different parts of soybean as well as in leaves of transgenic tobacco plants synthesizing soybean P5CR. P5CR activity was present in cytoplasm of soybean roots and nodules as well as in leaves, but in leaves, about 15% of the activity was detected in the plastid fraction. The location of P5CR was further confirmed by western blot assay of the proteins from cytosol and plastid fractions of different parts of the plant. Expression of soybean nodule cytosolic P5CR in transgenic tobacco under the control of cauliflower mosaic virus 35S promoter led to the accumulation of this protein exclusively in the cytoplasm, suggesting that the chloroplastic activity may be due to the presence of a plastid form of the enzyme. The different locations of P5CR in root and leaf suggested that proline may be synthesized in different subcellular compartments in root and leaf. Proline concentration was not significantly increased in transgenic plants exhibiting high level P5CR activity, indicating that reduction of P5C is not a rate-limiting step in proline production.

Topology and phosphorylation of soybean nodulin-26, an intrinsic protein of the peribacteroid membrane

Soybean nodulin-26, a homologue of bovine eye lens major intrinsic protein (MIP-26), is an integral protein of the peribacteroid membrane in symbiotic root nodules. It comprises 271 amino acids with six potential transmembrane domains and lacks an amino-terminal signal sequence. A full-length nodulin-26 cDNA and its various deletion derivatives were transcribed in vitro after linking them to bacteriophage T3 promoter. In vitro translation of these transcripts in a rabbit reticulocyte lysate, in the presence or absence of canine pancreatic microsomal membranes, suggested that nodulin-26 is cotranslationally inserted into the microsomes without a cleavable signal peptide. The first two transmembrane domains (103 amino acids) of the protein are sufficient for microsomal membrane insertion. Membrane-translocated nodulin-26 binds to Con-A and is sensitive to endoglycosidase-H treatment, suggesting that it is glycosylated. Native nodulin-26 from root nodules retains its sugar moiety as it, too, binds to Con-A. Chemical cleavage mapping at cysteine residues, a trypsin protection assay, and the Con-A binding affinity of nodulin-26 suggested that both the NH2 and COOH termini of this protein are on the cytoplasmic surface of the peribacteroid membrane, while the glycosidic residue is on the surface of the membrane facing the bacteroids. In vitro phosphorylation experiments showed that nodulin-26 is a major phosphorylated protein in the peribacteroid membrane. This phosphorylation is mediated by a Ca(2+)-dependent, calmodulin-independent protein kinase located in the peribacteriod membrane. Externally supplied acid phosphatase dephosphorylates this protein, but alkaline phosphatase does not. Based on its homology with several eukaryotic and prokaryotic channel-type membrane proteins, nodulin-26 may form a channel translocating specific molecules to the bacteroids during endosymbiosis in legume plants.

A preliminary observation on auto-cholinergic synapse dysfunction in patients with different types of epilepsy

Serum anti-acetylcholine receptor antibodies (A AchR Ab) and anti-synaptic premembrane antibodies (A PrM Ab) were measured in 21 patients with absence epilepsy, 21 cases with benign childhood epilepsy with centro-temporal spikes (BCECTs) and 13 cases with atypical epilepsy. Respectively, in five (23.8%), eleven (51.2%) and eight (66.7%) of the above mentioned groups of patients both A AchR Ab and A PrM Ab were found.

[Modification and expression of insecticidal protein structural gene of Bacillus thuringiensis var. aizawai 7-29]

The regulative region (181bp) and the fifth toxic active domain (217bp) were removed from the insecticidal protein gene of Bacillus thuringiensis var. aizawai 7-29. After the synthesis of the adaptor (15bp) that contains initiation codon (ATG) and the PCR synthesis of the fifth toxic active domain (229bp) that contains stop codon (TAA), were inserted into on 5' truncated and 3' truncated of the coding fod N-terminal peptid's DNA fragment, that to become a modified structural gene. The modified structural gene can be play initiatic translation-function and stop translation-function during translation of insecticidal protein. The insecticidal protein was determined by western blotting, showed the expression of modified structural gene in Escherichia coli JM 103. The bioassay of insecticidal proteins showed the 3' truncated and 5' truncated of insecticidal gene was higher toxic active than the 3' truncated of insecticidal gene in Escherichia coli JM 103.

Infectious RNA transcripts from Ross River virus cDNA clones and the construction and characterization of defined chimeras with Sindbis virus

We have constructed a full-length cDNA clone of the virulent T48 strain of Ross River virus, a member of the alphavirus genus. Infectious RNA can be transcribed from this clone using SP6 or T7 RNA polymerase. The rescued virus has properties indistinguishable from those of the T48 strain of Ross River virus. We have used this clone, together with a full-length cDNA clone of Sindbis virus, to construct chimeric plasmids in which the 5' and the 3' nontranslated regions of the Sindbis and Ross River genomes were exchanged. The nontranslated regions of the two viral genomes differ in both size and sequence although they maintain specific conserved sequence elements. Virus was recovered from all four chimeras. Chimeras containing heterologous 3' nontranslated regions had replicative efficiencies equal to those of the parents. In contrast, the chimeras containing heterologous 5' nontranslated regions were defective in RNA synthesis and virus production, and the severity of the defect was dependent upon the host. Replication of a virus containing a heterologous 5' nontranslated region may be inefficient due to the formation of defective protein-RNA complexes, whereas, the presumptive complexes formed between host or virus proteins and the 3' nontranslated region to promote RNA synthesis appear to function normally in the chimeras.

[Determination of megestrol acetate and estradiol valerate in injection of microencapsulated compound megestrol acetate by secondary derivative spectrophotometry]

The paper reports the simultaneous determination of megestrol acetate and estradiol valerate in the injection of microencapsulated compound megestrol acetate by secondary derivative spectrophotometry. The experimental results showed that the average recoveries of the two drugs were 98.8% and 98.0%, respectively, and that the coefficients of variation were 0.71% and 1.81%, respectively.

[Determination of berberine hydrochloride in traditional Chinese medicines containing Coptis chinensis Franch by reversed phase high performance liquid chromatography]

This paper reports a reversed phase high performance liquid chromatography method to determine berberine hydrochloride in Coptis chinensis Franch and in the traditional Chinese medicine containing Coptis chinensis Franch. The result shows that the mobile phase of 0.4mol/L ammonium nitratemethanol (52:48) can give a satisfactory separation. The extraction of sample with 1% H2SO4 solution using the ultrasonic vibration method is simple and easy to operate.

Mutagenesis of the 3' nontranslated region of Sindbis virus RNA

A cDNA clone from which infectious RNA can be transcribed was used to construct 42 site-specific mutations in the 3' nontranslated region of the Sindbis virus genome. The majority of these mutations were made in the 3'-terminal 19-nucleotide conserved sequence element and consisted of single nucleotide substitutions or of small (1 to 8) nucleotide deletions. An attempt was made to recover mutant viruses after transfection of SP6-transcribed RNA into chicken cells. In most cases, viable virus was recovered, but almost all mutants grew more poorly than wild-type virus when tested under a number of culture conditions. In the case of mutations having only a moderate effect, the virus grew as well as the wild type but was slightly delayed in growth. Mutations having a more severe effect led to lower virus yields. In many cases, virus growth was more severely impaired in mosquito cells than in chicken cells, but the opposite phenotype was also seen, in which the mutant grew as well as or better than the wild type in mosquito cells but more poorly in chicken cells. One substitution mutant, 3NT7C, was temperature sensitive for growth in chicken cells and severely crippled for growth in mosquito cells. Insertion mutations were also constructed which displaced the 19-nucleotide element by a few nucleotides relative to the poly(A) tail. These mutations had little effect on virus growth. Deletion of large regions (31 to 293 nucleotides long) of the 3' nontranslated region outside of the 19-nucleotide element resulted in viruses which were more severely crippled in mosquito cells than in chicken cells. From these results, the following principles emerge. (i) The entire 3' nontranslated region is important for efficient virus replication, although there is considerable plasticity in this region in that most nucleotide substitutions or deletions made resulted in viable virus and, in some cases, in virus that grew quite efficiently. Replication competence was particularly sensitive to changes involving the C at position 1, the A at position 7, and a stretch of 9 U residues punctuated by a G at position 14. (ii) The panel of mutants examined collectively deleted the entire 3' nontranslated region. Only mutants in which 8 nucleotides in the 3' terminal 19 nucleotides had been deleted or in which the 3' terminal C was deleted were nonviable. Although the 3' terminal C was essential for replication, it could be displaced by at least 7 nucleotides from its 3' terminal position adjacent to the poly(A) tract.(ABSTRACT TRUNCATED AT 400 WORDS)

Importance of the C terminus of plasmid Rts1 RepA protein for replication and incompatibility of the plasmid

RepA protein, essential for replication of plasmid Rts1, was found to bind in vivo immediately upstream of the repA promoter in studies with mini-Rts1 derivatives with deletions in the upstream region of repA. We constructed another series of repA mutants that would encode RepA derivatives containing oligopeptide substitutions in place of the carboxyl-terminal six amino acids. These modified RepA proteins could not activate ori (Rts1) at all and showed various degrees of incompatibility, or no incompatibility, toward a mini-Rts1 plasmid. These results suggest that the carboxyl-terminal six (or fewer) amino acids of RepA are important for exerting replication and incompatibility functions. One of the RepA derivatives, which showed an evident incompatibility without initiating replication, was examined for its ability to repress the repA gene.