Protection of OK-432, a Streptococcus pyogenes preparation, against lethal infection of mice with herpes simplex virus

We have studied the protective effect of OK-432, a biological response modifier (BRM) of Streptococcus pyogenes origin, on the lethal infection of mice with herpes simplex virus (HSV)-1. A single intraperitoneal (i.p.) injection of more than 10 micrograms of OK-432, when given at least two days before the infection, gave a marked effect yielding nearly 100% protection against ordinarily lethal infection. The protection was independent of the amount of infected virus inoculated. When given after the infection, the agent even at the maximal dose (100 micrograms), produced only a marginal effect. A single i.p. administration of OK-432 augmented the natural killer (NK) activity of peritoneal exudate cells and spleen mononuclear cells in mice 2 to 3 days after injection of OK-432, coinciding with the times when it induced a survival effect on HSV-infection. Treating OK-432-treated mice with a combination of an anti-macrophage agent, silica, and an anti-NK cell agent, anti-asialo GM1 serum, before infection diminished the antiviral effect of OK-432. The OK-432 protection against HSV infection was also markedly diminished in athymic nude mice. Thus, the protective effect of OK-432 on lethal HSV infection seems to be based on the activation of NK cells, macrophages, and T lymphocytes.     

A sensitive IL-1 thymocyte co-stimulator assay using a novel beta-D-galactoside specific lectin from the beetle, Allomyrina dichotoma

A sensitive thymocyte co-stimulator assay of IL-1 using a beta-D-galactoside specific lectin (allo A) obtained from the beetle (Allomyrina dichotoma) is reported here. Allo A stimulated [3H]thymidine uptake of mouse thymocytes in the presence of IL-1. The allo A assay was more sensitive than the PHA or PNA- thymocyte assay, especially at low doses of IL-1. Optimal conditions for the allo A assay were as follows: allo A, 2.5-5.0 micrograms/ml; whole thymocytes, 0.5-1.0 x 10(6) cells/well; incubation time, 72-96 hr. The assay is sensitive and convenient and can easily be performed in any laboratory.     

A possible correlation between histological changes in regional subcutaneous tissue induced by bacterial lipopolysaccharides and their adjuvant activities

Previously it was demonstrated that Klebsiella pneumoniae O3 lipopolysaccharide (KO3 LPS) exhibited much stronger adjuvant action on antibody response to subcutaneously (s.c.) injected sheep red blood cells or deaggregated bovine serum albumin than did other kinds of LPS, the R-form LPS lacking the O-specific polysaccharide chain of KO3 LPS (R-LPS), and the lipid A fractionated from KO3 LPS. We compared histological changes in the regional subcutaneous tissues of mice injected subcutaneously (s.c.) with KO3 LPS, the lipid A, and R-LPS. At the early stage after injection, KO3 LPS induced the infiltration of a large number of inflammatory cells, mainly polymorphonuclear leukocytes (PMN), at the site of injection. Neither R-LPS nor the lipid A induced the accumulation of PMN so much as KO3 LPS did. When injected s.c. with LPS from Escherichia coli O111 (EO111 LPS) and O55 (EO55 LPS), and Salmonella enteritidis (Sent LPS), the appearance of PMN at the regional site was much less than KO3 LPS. KO3 LPS could accumulate more 51Cr-labeled leukocytes at the injection site than EO111 LPS and Sent LPS. Administration of acetylsalicylic acid, which can inhibit leukocyte migration in inflammatory lesions, suppressed its adjuvant action. It was therefore suggested that the strong adjuvant action of KO3 LPS in s.c. injection might be dependent on its potent capability of accumulating PMN at the regional subcutaneous tissue. Furthermore, at the late stage after injection, the formation of several lymphoid follicles at the regional site was seen only in mice injected with KO3 LPS. It might be also related to the strong adjuvant action of KO3 LPS.     

Nucleotide sequence of the glutamine synthetase gene (glnA) and its upstream region from Bacillus cereus

We have determined the complete nucleotide sequence of a 2.4 kb chromosomal EcoT22I-NspV fragment, containing the Bacillus cereus glnA gene (structural gene of glutamine synthetase). The deduced amino acid sequence indicates that the glutamine synthetase subunit consists of 444 amino acid residues (50,063 Da). Comparisons are made with reported amino acid sequences of glutamine synthetases from other bacteria. Upstrem of glnA we found an open reading frame of 129 codons (ORF129) preceded by the consensus sequence for a typical promoter. Maxicell experiments showed two polypeptide bands, with molecular weights in good agreement with that of glutamine synthetase and that of ORF129, in addition to vector-coded protein. It is possible that the product of this open reading frame upstream of glnA has a regulatory role in glutamine synthetase expression.     

New methods to investigate ATP requirement for pre-mRNA splicing: inhibition by hexokinase/glucose or an ATP-binding site blocker

Addition of yeast hexokinase and glucose at various time points of the pre-mRNA splicing reaction rapidly depleted ATP and inhibited further progress of the reaction, indicating that ATP is required for both the first and second steps of splicing. ATP analogues, p-fluorosulfonylbenzoyl-5'-adenosine (FSBA) and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl), which can modify amino acids at the ATP-binding site of a protein, inactivated the splicing activity of the nuclear extract. While the inactivation by the former was irreversible, the splicing activity was complemented by a Micrococcal nuclease-treated extract. This ATP analogue (FSBA) may be a useful tool for identification of ATP-dependent splicing factors.     

Purification and catalytic properties of a cross-linked complex between adrenodoxin reductase and adrenodoxin

A stable covalent complex was prepared by cross-linking adrenodoxin reductase with adrenodoxin using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The covalent complex was purified extensively until free components were removed completely. The major component of the complex had a molecular weight of 63 kDa, which corresponds to a 1:1 stoichiometric complex between adrenodoxin reductase and adrenodoxin. NADPH-cytochrome c reduction activity of the covalent complex was comparable to that of an equimolar mixture of adrenodoxin reductase and adrenodoxin (native complex), and the NADPH-ferricyanide reduction activity of the complex was equal to that of the native one. In contrast to the native complex, the covalent complex produced much less superoxide upon NADPH-oxidation, and the covalent complex was found to be more stable than the native complex, suggesting that the complex state is more favorable for catalysis. From these results, we conclude that the adrenodoxin molecule does not need to dissociate from the complex during electron transfer from NADPH to cytochrome c.     

Activation and maturation mechanisms of boar acrosin zymogen based on the deduced primary structure

We have isolated cDNA clones encoding boar acrosin, a serine protease participating in the initial stage of fertilization, from boar testis lambda gt11 cDNA libraries. Nucleotide sequencing of the overlapping clones indicates that the composite cDNA inserts contain 1,391 base pairs coding for a 5'-untranslated region, an open reading frame, a stop codon, a 3'-untranslated region, and a poly(A)+ tail. A polyadenylation signal, AATAAA, is located 33 bases upstream from the start of the poly(A)+ tail. The amino acid sequence deduced from the cDNAs shows that boar acrosin is initially synthesized as a prepro-protein with a 16-residue signal peptide at the NH2 terminus. This signal sequence is followed by a 399-residue sequence corresponding to the acrosin zymogen. COOH-terminal sequence analysis of boar sperm 55-kDa proacrosin and its processed forms indicates that the mature acrosin molecule contains 322 amino acid residues in two polypeptide chains, a 23-residue light chain and a 299-residue heavy chain, with a combined molecular mass of 35,735 Da, and that the 55-kDa proacrosin molecule has 14-, 18-, and 43-residue segments as COOH-terminal extensions that are removed during proacrosin maturation. The COOH-terminal 43-residue segment is rich in proline residues, including an unusual repeat of 23 consecutive prolines. The deduced amino acid sequence of boar acrosin shows a high degree of identity with major portions of other serine proteases, including the active site region and the location of cysteine residues. We conclude that boar acrosin is synthesized as a single-chain polypeptide with the regions corresponding to the light and heavy chains covalently connected by two disulfide bonds, and that the single-chain molecule is autoactivated by cleavage of the Arg23-Val24 bond after removal of the COOH-terminal 14-residue segment, resulting in the formation of the light and heavy chains. This two-chain molecule is then converted to the mature enzyme by removal of the COOH-terminal 18- and 43-residue segments.     

Synthetic inositol trisphosphate analogs and their effects on phosphatase, kinase, and the release of Ca2+

A series of inositol 1,4,5-trisphosphate (IP3) analogs and positional isomers was examined to explore the structure-activity relationships among IP3 5-phosphatase, IP3 3-kinase, and the release of Ca2+. All analogs with additional groups on the 2nd position of IP3 inhibited the hydrolysis of [5-32P]IP3 catalyzed by erythrocyte ghosts, with a lower Ki value than seen with IP3. IP3 dehydroxylated at the 2nd position also had a lower Ki, while 2,4,5-IP3 or cyclic(1:2), 4,5-IP3 had higher Ki values. Among these compounds 2-deoxy-IP3 was as potent as IP3 in inhibiting the phosphorylation by [3H] IP3-3-kinase in rat brain cytosol. The other compounds, except for 2,4,5-IP3 inhibited the phosphorylation, however, 2-30 times higher concentrations were required. By lowering free Ca2+, the concentrations required for half-maximal inhibition were low, while those of IP3, 2-deoxy-IP3, and positional isomers remained unchanged. These compounds acted as full agonists in releasing Ca2+ from permeabilized macrophages, although 1.6-50-fold higher concentrations than IP3 were required. These compounds also inhibited the binding of [3H]IP3 to rat cerebellum and bovine adrenal cortex microsomes, but the potencies were 2.9-33 times less than that of IP3. Thus, the 2nd position of IP3 can be modified with only a slight loss of biological activity.     

Alternative splicing mechanism in a cytochrome P-450 (P-450PB-1) gene generates the two mRNAs coding for proteins of different functions

Two mRNAs for P-450PB-1 and P-450PB-1(ps) are about 2 kilobase pairs long and have identical sequences with each other except for one short region of high variability (Kimura, H., Yoshioka, H., Sogawa, K., Sakai, Y., and Fujii-Kuriyama, Y. (1988) J. Biol. Chem. 263, 701-707). To clarify the origin of the short replacement block between the two mRNAs, we isolated several genomic clones containing relevant gene sequences. Sequence analysis of these genomic clones revealed that the two short segments specific for the two mRNAs are tandemly arranged in a genomic sequence and form exonic sequences equipped with AG and GT sequences on their 5' and 3' ends, respectively, and the putative consensus sequences for the lariat formation. The two short sequences lie between the two exonic sequences coding for the common part of the two mRNAs. Taken together with the structure of the related P-450(M-1) gene (Morishima, N., Yoshioka, H., Higashi, Y., Sogawa, K., and Fujii-Kuriyama, Y. (1987) Biochemistry 26, 8279-8285), all these results clearly demonstrate that the two mRNAs are generated from a single gene by alternative splicing at the eighth exons. The synthesis of the two mRNAs is regulated temporally in livers of male and female rats and brains of the female animals. One of the two mRNAs codes for a monooxygenase of P-450PB-1, and the other (P-450PB-1(ps) mRNA) lacks the sequence coding for the heme-binding site conserved among all species of P-450 molecules, and, therefore, it cannot function as a monooxygenase. The immunoblot analysis using an antibody specific for the 15-mer peptide uniquely encoded by P-450PB-1(ps) mRNA shows that the P-450PB-1(ps) peptide is synthesized at least in rat livers of both sexes in temporally regulated manners and is bound to the microsomal membranes. The function of this peptide remains to be seen.     

Synthesis of protein and mRNA is necessary for transition of suspension-cultured Catharanthus roseus cells from the G1 to the S phase of the cell cycle

The effects of inhibition of the synthesis of protein, mRNA or rRNA on the progression of the cell cycle have been analyzed in cultures of Catharanthus roseus in which cells were induced to divide in synchrony by the double phosphate starvation method. The partial inhibition of protein synthesis at the G₁ phase by anisoniycio or cycloheximide caused the arrest of cells in the G₁ phase or delayed the entry of cells into the S phase. When protein synthesis was partially inhibited at the S phase, cell division occurred to about the same extent as in the control. When asynchronously dividing cells were treated with cycloheximide, cells accumulated in the G₁ phase, as shown by flow-cytometric analysis. The partial inhibition of mRNA synthesis by α-amanitin at the G₁ phase caused the arrest of cells in the G₁ phase, although partial inhibition of mRNA synthesis at the S phase had little effect on cell division. In the case of inhibition of synthesis of rRNA by actinomycin D at the G₁ phase, initiation of DNA synthesis was observed, but no subsequent DNA synthesis or the division of cells occurred. However, the addition of actinomycin D during the S phase had no effect on cell division. These results suggest that specific protein(s), required for the progression of the cell cycle, are synthesized in the G₁ phase, and that the mRNA(s) that encode these proteins are also synthesized at the G₁ phase.