Identification and expression of a human cytomegalovirus early glycoprotein.

A human cytomegalovirus early gene which possesses three temporally regulated promoters is located in the large unique component of the viral genome between 0.054 and 0.064 map units (C.-P. Chang, C.L. Malone, and M.F. Stinski, J. Virol. 63:281-290, 1989). This gene contains a major open reading frame (ORF) located 233 bases downstream of the cap site of an early unspliced RNA. The major ORF predicts a polypeptide of 17 kilodaltons (kDa) which contains a glycoproteinlike signal and anchor domains as well as potential N-glycosylation sites. Antisera were prepared against synthetic peptides derived from amino acid sequences within the major ORF. The antisera detected a viral glycoprotein of 48 kDa in infected cells and recognized the in vitro-translated 17-kDa protein early-gene product. The viral glycoprotein, designated gp48, was modified by N-linked glycans and possibly O-linked glycans. The synthesis of gp48 occurred in the absence of viral DNA replication but accumulated to the highest levels at late times after infection. Since gp48 was found in the virion, it is considered an early structural glycoprotein.     

Cloning of a creatinase gene from Pseudomonas putida in Escherichia coli by using an indicator plate.

A genomic library of Pseudomonas putida DNA was constructed by using plasmid pBR322. Transformants of Escherichia coli in combination with Proteus mirabilis cells grown on creatinase test plates were screened for creatinase activity; transformants were considered positive for creatinase activity if a red-pink zone appeared around the colonies. One creatinase-positive clone was further analyzed, and the gene was reduced to a 2.7-kb DNA fragment. A unique protein band (with a molecular weight of approximately 50,000) was observed in recombinant E. coli by minicell analysis.     

Properties of a 72-kilodalton mosquitocidal protein from Bacillus thuringiensis subsp. morrisoni PG-14 expressed in B. thuringiensis subsp. kurstaki by using the shuttle vector pHT3101.

The mosquitocidal properties of Bacillus thuringiensis subsp. israelensis and B. thuringiensis subsp. morrisoni PG-14 are attributable to protein inclusions grouped together within a parasporal body. In both of these strains, the mosquitocidal activity resides in proteins with molecular masses of 27, 72, 128, and 135 kDa. In an attempt to determine the toxicity of each protein, the shuttle vector pHT3101 was used to express the cryIVD gene (encoding the 72-kDa CryIVD protein) from B. thuringiensis subsp. morrisoni in an acrystalliferous mutant of B. thuringiensis subsp. kurstaki. With this system, parasporal inclusions of the 72-kDa protein were obtained that were comparable in size, shape, and toxicity to those produced by parental B. thuringiensis subsp. morrisoni. The inclusions were bar shaped, measured 500 by 300 by 150 nm, and were easily visible with phase-contrast microscopy by 16 h of cell growth. A 50% lethal concentration of 64 ng/ml for these inclusions was determined in bioassays against fourth instars of Culex quinquefasciatus, which was similar to the 50% lethal concentration of 55 ng/ml obtained for the 72-kDa inclusion from B. thuringiensis subsp. israelensis. In contrast, expression of the cryIVD gene in Escherichia coli was very low and only detectable by immunoblot analysis. These results demonstrate that the pHT3101-B. thuringiensis expression system can be used to express the CryIVD protein in quantities and with properties comparable to that obtained with the natural host. This system may prove useful for the expression of other B. thuringiensis proteins and, in particular, for reconstitution experiments with inclusions produced by the mosquitocidal subspecies of B. thuringiensis.     

Ancestry of the 4-chlorobenzoate dehalogenase: analysis of amino acid sequence identities among families of acyl:adenyl ligases, enoyl-CoA hydratases/isomerases, and acyl-CoA thioesterases.

We have deduced the nucleotide sequence of the genes encoding the three components of 4-chlorobenzoate (4-CBA) dehalogenase from Pseudomonas sp. CBS-3 and examined the origin of these proteins by homology analysis. Open reading frame 1 (ORF1) encodes a 30-kDa 4-CBA-coenzyme A dehalogenase related to enoyl-coenzyme A hydratases functioning in fatty acid beta-oxidation. ORF2 encodes a 57-kDa protein which activates 4-CBA by acyl adenylation/thioesterification. This 4-CBA:coenzyme A ligase shares significant sequence similarity with a large group of proteins, many of which catalyze similar chemistry in beta-oxidation pathways or in siderophore and antibiotic synthetic pathways. These proteins have in common a short stretch of sequence, (T,S)(S,G)G(T,S)(T,E)G(L,X)PK(G,-), which is particularly highly conserved and which may represent an important new class of "signature" sequence. We were unable to find any proteins homologous in sequence to the 16-kDa 4-hydroxybenzoate-coenzyme A thioesterase encoded by ORF3. Analysis of the chemistry and function of the proteins found to be structurally related to the 4-CBA:coenzyme A ligase and the 4-CBA-coenzyme A dehalogenase supports the proposal that they evolved from a beta-oxidation pathway.     

Assay for L-pipecolate oxidase activity in human liver: detection of enzyme deficiency in hyperpipecolic acidaemia.

A direct assay method is described for L-pipecolate oxidase. The assay uses NaHSO3 to trap the L-alpha-amino [3H]adipate delta-semialdehyde (AAS) formed as a direct reaction product of L-pipecolate oxidase from L-[3H]pipecolic acid. The adduct so formed was separated from the substrate on Dowex 50 (H+) column. The product was identified as [3H]AAS by amino acid analysis after breaking down the adduct by boiling under acidic conditions. The assay is simpler and more specific than fluorometric methods; it is also more sensitive, requiring at most 16 micrograms of liver peroxisome-enriched protein per assay. We have used this assay procedure to detect L-pipecolate oxidase in skin fibroblasts obtained from a control subject and from patients of hyperpipecolic acidaemia and Zellweger syndrome and found that this enzyme activity is present in the control, but absent or decreased in the patients with the peroxisomal disorders.     

Increased shikonin production inLithospermum erythrorhizon suspension cultures within situ extraction and fungal cell treatment (elicitor)

Summary The effect ofin situ extraction and elicitor treatment on shikonin production was studied with the suspension cultures ofLithospermum erythrorhizon. Shikonin concentration of 60 mg/L was achieved by the use of both techniques which was 24 times higher than that of control culture, and 65 times higher in terms of shikonin productivity. The host-pathogen effect of elicitor treatment andin situ extraction for product removal were effective for shikonin production.     

Identification of the origin of replication of the eukaryote Dictyostelium discoideum nuclear plasmid Ddp2

Ddp2 is a 5.8-kb, high-copy-number, nuclear plasmid found in the eukaryote Dictyostelium discoideum. We have identified two functional domains, a large open reading frame (Rep gene) and a 626-bp fragment containing an origin of replication (ori). The ori, when cloned into a shuttle vector, confers stable extrachromosomal replication in D. discoideum, provided that the Rep gene, which acts in trans, is integrated into the host genome. Ddp2 carries a 501-bp imperfect inverted repeat, and part of the ori overlaps with one of these repeats. The ori sequence contains two direct repeats of 49 bp comprising two 10-bp "TGTCATGACA" palindromes separated by a poly(T.A) sequence. Deletion of either 49-bp repeat abolished extrachromosomal replication.     

Oxidation and cleavage of 3-aminopyridine adenine dinucleotide phosphate with periodate

Treatment of 3-aminopyridine adenine dinucleotide phosphate with sodium periodate in the neutral pH resulted in oxidation of the ribose linked to 3-aminopyridine and cleavage of the dinucleotide into adenosine- and 3-aminopyridine-containing moieties. Separation of these moieties was afforded by thin-layer chromatography, high-performance liquid chromatography, and fast protein liquid chromatography. From fast atom bombardment mass spectra and nuclear magnetic resonance spectra, the adenosine-containing moiety was identified as 2'-phosphoadenosine 5'-phosphate while the aminopyridine moiety was present in a mixture of the hydrated 3-aminopyridine mononucleotide/nucleoside dialdehyde. Separation of the completely oxidized product by Pharmacia fast protein liquid chromatography gave three major peaks corresponding to 2'-phosphoadenosine 5'-phosphate, 2'-phosphoadenosine 5'-diphosphate and oxidized 3-aminopyridine nucleoside, with minor amount of oxidized 3-aminopyridine mononucleotide. Thus the oxidized 3-aminopyridine adenine dinucleotide phosphate was shown to cleave by two pathways: it may either undergo beta-elimination to give 2'-phosphoadenosine 5'-diphosphate and oxidized 3-aminopyridine nucleoside; or the phosphodiester linkage may be hydrolyzed to give 2'-phosphoadenosine 5'-phosphate and oxidized 3-aminopyridine mononucleotide. The latter compound may further undergo beta-elimination and eventually give oxidized 3-aminopyridine nucleoside. Hydrolysis could be prevented by storing the sample as lyophilized powder, while beta-elimination was diminished by lowering the storage temperature. We found that the lyophilized powder of oxidized 3-aminopyridine adenine dinucleotide phosphate can be stored at -50 degrees C for several months with minimum decomposition.     

Lung and chest wall mechanics in rabbits during high-frequency body-surface oscillation

In eight anesthetized and tracheotomized rabbits, we studied the transfer impedances of the respiratory system during normocapnic ventilation by high-frequency body-surface oscillation from 3 to 15 Hz. The total respiratory impedance was partitioned into pulmonary and chest wall impedances to characterize the oscillatory mechanical properties of each component. The pulmonary and chest wall resistances were not frequency dependent in the 3- to 15-Hz range. The mean pulmonary resistance was 13.8 +/- 3.2 (SD) cmH2O.l-1.s, although the mean chest wall resistance was 8.6 +/- 2.0 cmH2O.l-1.s. The pulmonary elastance and inertance were 0.247 +/- 0.095 cmH2O/ml and 0.103 +/- 0.033 cmH2O.l-1.s2, respectively. The chest wall elastance and inertance were 0.533 +/- 0.136 cmH2O/ml and 0.041 +/- 0.063 cmH2O.l-1.s2, respectively. With a linear mechanical behavior, the transpulmonary pressure oscillations required to ventilate these tracheotomized animals were at their minimal value at 3 Hz. As the ventilatory frequency was increased beyond 6-9 Hz, both the minute ventilation necessary to maintain normocapnia and the pulmonary impedance increased. These data suggest that ventilation by body-surface oscillation is better suited for relatively moderate frequencies in rabbits with normal lungs.     

Arachidonic acid causes cyclooxygenase-dependent and -independent pulmonary vasodilation

In this study we examined the action of arachidonic acid in the isolated rat lung perfused with a cell- and protein-free physiological salt solution. When pulmonary vascular tone was elevated by hypoxia, bolus injection of a large dose of arachidonic acid (75 micrograms) caused transient vasoconstriction followed by vasodilation. When arachidonic acid (100 micrograms) was injected during normoxia and at base-line perfusion pressure (low vascular tone) or when vascular tone was elevated by KCl, arachidonic acid (50 micrograms) caused only vasoconstriction. Doses less than 7.5 micrograms caused vasodilation only when injected during hypoxic vasoconstriction and subsequent blunting of either angiotensin II- or hypoxia-induced pulmonary vasoconstriction. The higher doses of arachidonic acid (7.5 and 75 micrograms), but not the lower doses (7.5-750 ng), caused increases in effluent 6-ketoprostaglandin F1 alpha, thromboxane B2, and prostaglandin E2 and F2 alpha. 6-Ketoprostaglandin F1 alpha was the major cyclooxygenase product. Meclofenamate (10(-5) M) blocked the increased metabolite synthesis over the entire dose range of arachidonic acid tested (7.5 ng-75 micrograms). Because vasodilation immediately after arachidonic acid was cyclooxygenase-independent, we investigated whether this effect was due to the unsaturated fatty acid properties of arachidonic acid and compared its action with that of oleic acid and docosahexaenoic acid. Because neither compound mimicked the vasodilation observed with arachidonic acid, we concluded that the cyclooxygenase-independent action of arachidonic acid could not be explained by unsaturated fatty acid properties per se. Because 1-aminobenzotriazole, a cytochrome P-450 inhibitor, partially inhibited the immediate arachidonic acid-induced pulmonary vasodilation, we concluded that cytochrome P-450-dependent metabolites can account for some of the cyclooxygenase-independent vasodilation of arachidonic acid.