Taxonomic characterization of closely related Streptomyces spp. based on the amino acid sequence analysis of protease inhibitor proteins

Amino acid sequences of protease inhibitors (Streptomyces subtilisin inhibitor-like proteins) widely distributed in Streptomyces were compared to clarify the taxonomic status of three strains of Streptomyces spp., S. coelicolor A3(2), S. lividans 66 and S. coelicolor Müller, which are closely related by conventional taxonomical procedures. The sequence comparison indicated that S. coelicolor A3(2) is distinct from the type strain S. coelicolor Müller, but belongs to the same taxon as S. lividans 66.

Use of enzyme-linked-immunosorbent assay for detection of IgG and IgM antibodies to Fusobacterium necrophorum in cattle

An enzyme-linked-immunosorbent assay (ELISA) with HCl heat-extracted antigen of Fusobacterium necrophorum was conducted to detect specific immunoglobulins G and M in infected cattle. The ELISA revealed an increase (> 0.40) in specific IgG in most of the animals with hepatic abscesses but not that in specific IgM. All the lesions were positive for F. necrophorum. These findings indicated that the ELISA for immunoglobulin G detection may prove to be a useful tool for predictive serodiagnosis of F. necrophorum infection in cattle.

Efficacy of gentian violet in the eradication of methicillin-resistant Staphylococcus aureus from skin lesions

The efficacy of gentian violet (Gv) in eradicating methicillin-resistant Staphylococcus aureus (MRSA) in decubitus ulcers was investigated. Decubitus ulcers (a total of 18 cases) were scrubbed with Gv aqueous solution 0.1% and ointment containing Gv 0.1% was applied daily. MRSA was not detected in these lesions for 3-34 days (average, 10.5 +/- 2.5 days) after the application of Gv ointment. Before this trial, all patients were treated with povidone-iodine and antibiotics; however, those treatments were not effective in eradicating MRSA from skin lesions. Skin irritation and other systemic side effects caused by Gv were not observed. Our data suggest that Gv is a useful agent for treatment of the decubitus ulcers infected with MRSA.

Streptomyces serine protease (SAM-P20): recombinant production, characterization, and interaction with endogenous protease inhibitor

Previously, we isolated a candidate for an endogenous target enzyme(s) of the Streptomyces subtilisin inhibitor (SSI), termed SAM-P20, from a non-SSI-producing mutant strain (S. Taguchi, A. Odaka, Y. Watanabe, and H. Momose, Appl. Environ. Microbiol. 61:180-186, 1995). In this study, in order to investigate the detailed enzymatic properties of this protease, an overproduction system of recombinant SAM-P20 was established in Streptomyces coelicolor with the SSI gene promoter. The recombinant SAM-P20 was purified by salting out and by two successive ion-exchange chromatographies to give a homogeneous band by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Partial peptide mapping and amino acid composition analysis revealed that the recombinant SAM-P20 was identical to natural SAM-P20. From the results for substrate specificity and inhibitor sensitivity, SAM-P20 could be categorized as a chymotrypsin-like protease with an arginine-cleavable activity, i.e., a serine protease with broad substrate specificity. For proteolytic activity, the optimal pH was 10.0 and the optimal temperature was shifted from 50 to 80 degrees C by the addition of 10 mM calcium ion. The strong stoichiometric inhibition of SAM-P20 activity by SSI dimer protein occurred in a subunit molar ratio of these two proteins of about 1, and an inhibitor constant of SSI toward SAM-P20 was estimated to be 8.0 x 10(-10) M. The complex formation of SAM-P20 and SSI was monitored by analytical gel filtration, and a complex composed of two molecules of SAM-P20 and one dimer molecule of SSI was detected, in addition to a complex of one molecule of SAM-P20 bound to one dimer molecule of SSI. The reactive site of SSI toward SAM-P20 was identified as Met-73-Val-74 by sequence analysis of the modified form of SSI, which was produced by the acidification of the complex of SSI and SAM-P20. This reactive site is the same that toward an exogenous target enzyme, subtilisin BPN'.

Microbial secretion of biologically active human transforming growth factor alpha fused to the Streptomyces protease inhibitor

A secretory production system for the active form of transforming growth factor alpha (TGF alpha) was established in Streptomyces lividans using a gene encoding the secretory protease inhibitor, Streptomyces subtilisin inhibitor (SSI). It was demonstrated that deletion of one of the putative dual ssi terminators is effective to extracellularly produce a heterologous polypeptide in a fused form. The recombinant fusion protein, SSI::TGF alpha, was purified to homogeneity by a combination of hydrophobic chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). It was noteworthy that the SSI::TGF alpha hybrid protein exhibited bifunctional activity: the TGF alpha activity for cell growth promotion and the inhibitory activity of SSI. Taken together with the results of analytical gel filtration, these findings strongly indicate that each moiety in the fusion protein correctly folds and the whole hybrid molecule exists in a dimeric form, which results in its bifunctional activity.

A single skeletal muscle powered ventricle that assists both systemic and pulmonary circulations

Extraaortic counterpulsation using skeletal muscle powered ventricles (SMPVs) has been studied mainly for the purpose of assisting the systemic circulation. The purpose of this study was to investigate the possibility of assisting both the systemic and pulmonary circulations using a single SMPV. An SMPV that counterpulses the systemic circulation is placed beside the right atrium (RA) or the right ventricle (RV), the former after procedures such as a Fontan operation, and the latter in cases of biventricular failure. Because the SMPV dilates passively during cardiac systole, it is designed to press the RA or the RV directly from outside. This study is a preliminary report, and only the ability of a specially constructed SMPV to dilate was assessed. Using seven dogs with heart failure, the SMPV dilated with an internal pressure of 88 mmHg and 1.0 cm, while the volume inside increased by 10.8 ml. From these results, it is suggested that the SMPV has enough dilating power to press the RA or to assist the RV while counterpulsing the systemic circulation.

Molecular cloning and sequence analysis of a gene encoding an extracellular serine protease from Streptomyces lividans 66

A gene encoding a homolog of the chymotrypsin-like serine protease (SAM-P20), which was isolated as the target enzyme of a protease inhibitor (SSI), was cloned from Streptomyces lividans 66. This gene contained an open reading frame of 1065 nucleotides encoding 354 amino acid residues with a putative prepro portion of 157 amino acid residues. The deduced amino acid sequence of the cloned gene had significant homology to those of members of Streptomyces extracellular chymotrypsin-like protease family. By Southern blot analysis, it was suggested that protease genes of this type are found at a high frequency in Streptomyces. In this sense, we propose to categorize this protease as a member of the 'SAL' series (SAM-P20-like proteases).

Sensitization of nociceptive C-fibers in zinc-deficient rats

A marked decrease in zinc concentration was observed in plasma (P < 0.001), hindpaw skin (P < 0.01), and dorsal skin (P < 0.01) in zinc-deficient rats (rats fed a zinc-deficient diet for 3 wk), compared with the control rats fed the same zinc-deficient diet supplemented with ZnCO3 (50 mg/kg diet). The threshold intensity needed to elicit vasodilatation in the hindpaw skin of the zinc-deficient rats on electrical stimulation of the saphenous nerve in a peripheral direction was markedly lower (P < 0.01) than that in the control rats. No difference was observed between control (n = 5) and zinc-deficient rats (n = 5) in the magnitude of the plasma extravasation evoked by either histamine or substance P. There was no difference between control and zinc-deficient rats in terms of the dose-response curve for release of histamine by substance P. Prostaglandin E2 (PGE2) concentration in the hindpaw skin of the zinc-deficient rats was nearly fourfold higher (P < 0.01) than that of the control rats, whereas no difference in the leukotriene B4 level in the hindpaw skin was observed between control and zinc-deficient rats. From the present study, it seems likely that an increased level of PGE2 in the vicinity of the nociceptive C-fiber terminals in the hindpaw skin of zinc-deficient rats may sensitize the terminals of the nociceptive C-fibers of the saphenous afferent nerve in the hindpaw and thus facilitate the production of antidromic vasodilatation.

Dermatoglyphic (fingerprint) pattern in biliary atresia

The dermatoglyphic (fingerprint) patterns of 288 patients with biliary atresia (117 males and 171 females) were compared to those of normal Japanese. Arches and radial loops were seen more frequently than the normal distribution on thumb, ring- and little-fingers. Nineteen percent of the patients had abnormal fingerprint patterns.

A subtilisin inhibitor produced by Streptomyces bikiniensis possesses a glutamine residue at reactive site P1

We determined the complete amino acid sequence of a novel subtilisin inhibitor, SIL15, which had been isolated from the culture supernatant of Streptomyces bikiniensis and shown to be a member of the Streptomyces subtilisin inhibitor (SSI)-like (SIL) protein family, and then identified its reactive site. SIL15 is composed of 113 amino acids and exists as a dimer. Compared with other SSI-family inhibitors, SIL15 was found to be unique in that it possesses a Gln residue at the P1 site of the reactive site and has two-residue insertions in two regions, one in the alpha 1-helix and the other in the flexible loop region near the reactive site. Inhibition of subtilisin BPN' by SIL15 (inhibitor constant, 2.7 x 10(-11) M) was due to the presence of a Gln residue at the P1 site, which was well consistent with the results obtained for P1-site mutants of SSI and turkey ovomucoid domain 3.

Molecular characterization of a gene encoding extracellular serine protease isolated from a subtilisin inhibitor-deficient mutant of Streptomyces albogriseolus S-3253

An extracellular serine protease produced by a mutant, M1, derived from Streptomyces albogriseolus S-3253 that no longer produces a protease inhibitor (Streptomyces subtilisin inhibitor [SSI]) was isolated. A 20-kDa protein was purified by its affinity for SSI and designated SAM-P20. The amino acid sequence of the amino-terminal region of SAM-P20 revealed high homology with the sequences of Streptomyces griseus proteases A and B, and the gene sequence confirmed the relationships. The sequence also revealed a putative amino acid signal sequence for SAM-P20 that apparently functioned to allow secretion of SAM-P20 from Escherichia coli carrying the recombinant gene. SAM-P20 produced by E. coli cells was shown to be sensitive to SSI inhibition.

Primary structure and inhibitory properties of a subtilisin-chymotrypsin inhibitor from Streptomyces virginiae

A novel serine protease inhibitor SIL8, which was isolated from the culture medium of Streptomyces virginiae and shown to be a member of the Streptomyces subtilisin-inhibitor-like (SIL) inhibitor family by sequence analysis of its amino-terminal region [Taguchi, S., Kikuchi, H., Kojima, S., Kumagai, I., Nakase, T., Miura, K. & Momose, H. (1993) Biosci. Biotech. Biochem. 57, 522-524], is the first SIL inhibitor demonstrated to show marked inhibitory activity toward alpha-chymotrypsin, in addition to strong inhibitory activity toward subtilisin BPN', a common property of inhibitors of the Streptomyces subtilisin inhibitor (SSI) family. In this study, the complete amino acid sequence of SIL8 was determined from the sequence analysis of peptides obtained by specific cleavage at the reactive site and by enzymic digestion. SIL8 was shown to exist as a dimer protein, each subunit of which was composed of 111 amino acids, and to have less than 50% similarity with other SSI-family inhibitors, indicating its most distant relationship to other members of this family. Insertion of two residues was observed in the flexible loop region of SIL8, and amino acid replacements were found not only on the molecular surface but also in the beta-sheet and hydrophobic core, suggesting that packing rearrangements of the side chains may occur in these regions to maintain the tertiary and quaternary structures. The inhibitor constants Ki obtained using synthetic substrates are 92 pM for subtilisin BPN' and 11 nM for alpha-chymotrypsin. The P1 site was was identified as methionine, which was in good agreement with the substrate specificity of alpha-chymotrypsin. SSI, which also possesses a methionine residue at the P1 site, inhibits alpha-chymotrypsin poorly (inhibitor constant, 4.0 microM). Such a difference in the inhibitory properties of SIL8 and SSI toward alpha-chymotrypsin is discussed on the basis of the structures of the inhibitors.

Three novel subtilisin-trypsin inhibitors from Streptomyces: primary structures and inhibitory properties

Three novel proteinaceous inhibitors, which had been identified as "Streptomyces subtilisin inhibitor-like (SIL) proteins" and exhibited trypsin inhibition in addition to strong inhibition toward subtilisin BPN', were purified from the culture broth of three Streptomyces strains: SIL10 from S. thermotolerans, SIL13 from S. galbus, and SIL14 from S. azureus. Their primary structures were determined by sequence analysis of intact SIL inhibitors and peptides obtained by enzymatic digestions of S-pyridylethylated SIL inhibitors. These inhibitors were composed of about 110 amino acids and existed as dimer proteins. The reactive site was identified as Lys-Gln for all three inhibitors by sequence analysis of their modified forms in which the reactive-site peptide bond was specifically cleaved by subtilisin BPN' under acidic conditions. Thus, their inhibition toward trypsin and subtilisin BPN' was due to the presence of a Lys residue at the P1 site. Inhibitor constants toward subtilisin BPN' and trypsin were also determined. These inhibitors showed relatively high sequence homology to other SSI-family inhibitors possessing a Lys residue at the P1 site, with amino acid replacements on their molecular surface.

In vivo monitoring system for structure-function relationship analysis of the antibacterial peptide apidaecin

A unique antibacterial peptide derivative found in immune honeybee lymph, apidaecin 1b (AP1), was randomly mutagenized and characterized by a newly established system to analyze in vivo its structure-function relationship. Initially, a high-level expression host-vector system for AP1 in Escherichia coli was constructed by creating a fusion protein with the highly stable Streptomyces subtilisin inhibitor (SSI) molecule. Expression of the SSI-AP1 fusion protein was found to depend on the concentration of the transcriptional inducer isopropyl-beta-D-thio-galactopyranoside (IPTG) and to parallel the degree of growth inhibition of the transformant cells. Subsequently, apidaecin derivatives produced by localized random mutagenesis were screened with this IPTG concentration-controlled in vivo system by monitoring the growth inhibition patterns of the transformant cells. One mutant apidaecin (P9L) that had reduced activity was purified and isolated from the periplasmic fraction of an E. coli transformant. Its antibacterial activity was reduced to one-third of that of wild-type apidaecin. When considered together with the other mutations, it was concluded that several Pro residues, including that at the ninth position, are responsible for expression of the antibacterial action of apidaecin.

The effect of stimulating voltage on time characteristics of contraction in cardiomyoplasty

In cardiomyoplasty (CMP), the strength of a skeletal muscle increases as the stimulating voltage increases. On the other hand, timing of stimulation in CMP is a problem not yet solved. This experiment assessed the relationship between stimulating voltage and time characteristics in the contraction of skeletal muscles. In acute experiments using rabbits, the time required to reach maximal muscle contraction did not change significantly with voltage. In conclusion, stimulation voltage does not affect time characteristics. Thus, the best timing of stimulation in CMP can be assessed independently of voltage.

A miniaturized centrifugal pump for assist circulation

The newly developed Nikkiso HMS-15 is a miniaturized centrifugal pump. It has an impeller diameter of only 50 mm and a priming volume of only 25 ml. A totally new approach was applied to develop this very small pump. The new pump showed comparable hemolysis with pumps twice as big (e.g., the most widely used cone-shaped centrifugal pump [index of hemolysis, 0.005]). This finding refutes the belief that the pump diameter must be sufficiently large in size. Clinical application for cardiac assist was performed for 48 h without any thrombus formation despite low heparin dosage. Also, the pump showed quite favorable blood trauma when applied as a pump for cardiopulmonary bypass during open heart surgery. The compactness, the high controllability, and the system versatility proved to be very effective for clinical application. This pump is considered very reliable for its highly optimized design.

[Synergism on the bactericidal effect of gentian violet (Gv) and acrinol (Ac) against Pseudomonas aeruginosa]

The MBCs of Ac against P. aeruginosa (7 strains) isolated from infected skin lesions of patients were more than 6400 micrograms/ml, and those of Gv were more than 1600 micrograms/ml. When either Ac or Gv was used independently, these dyes did not have the bactericidal effect of P. aeruginosa. When Gv was used in combination with Ac, predominantly synergism on the bactericidal effect of Ac and Gv against P. aeruginosa was observed. The MBCs of an Ac-Gv cocktail were between 100 micrograms/ml and 225 micrograms/ml. We have previously reported that Gv possessed significantly a bactericidal effect to MRSA isolated from clinical specimens. Therefore, these results suggested that a combination treatment by an Ac-Gv cocktail may be one of the useful drugs for the MRSA and P. aeruginosa mixed infection on the skin lesions which is frequently observed clinically.

Primary structure and inhibitory properties of a proteinase inhibitor produced by Streptomyces cacaoi

Protein proteinase inhibitors showing sequence homology with Streptomyces subtilisin inhibitor (SSI) have been found to be distributed widely in Streptomyces species, and accordingly have been named SSI-like (SIL) proteins. SIL1 from S. cacaoi was the first of these proteins to be isolated and to be given a serial number. To study the structure-function relationship of SIL proteins, we determined the primary structure of SIL1 and measured its inhibitory activities. It was found to be composed of 110 amino acids and to exist in dimer form. The amino-acid sequence of SIL1 was unique among other characterized SIL proteins in having a one-residue deletion in two regions and a three-residue insertion in the flexible loop region. Sequence comparison indicated that SIL1 was distantly related to other members of the SSI family, and that amino-acid replacements had occurred not only on the surface of the SIL1 molecule but also in the beta-sheet region. The reactive site of SIL1 was considered to be Arg70-Glu71 from sequence alignment with other SSI-family inhibitors. SIL1 inhibited subtilisin BPN' strongly with an inhibitor constant (Ki) of 2.8 x 10(-11) M, like other members of the SSI family possessing an Arg residue at the P1 site. In contrast, SIL1 exhibited weak inhibition toward trypsin with a Ki value of 5.5 x 10(-8) M, possibly as a consequence of insertion of the three residues in the flexible loop region near the reactive site. This contrast seems to be due to the difference in the subsite structure of the two proteinases.

[Screening for thyroid dysfunction in adults residing in Hokkaido Japan: in relation to urinary iodide concentration and thyroid autoantibodies]

The prevalence of thyroid dysfunction and its relation to thyroid autoantibodies (TAA) and urinary iodide concentration (UI) was studied in apparently healthy adults in Sapporo (n = 4110) (Sapporo group), and in five coastal areas of Hokkaido (n = 1061) (coastal group) which produce iodine-rich seaweed (kelp). The frequency of above normal UI (high UI) in the morning urinary samples of coastal group was 10.8%, significantly higher than that of Sapporo group (6.4%) (p < 0.001). Frequency of positive TAA in both groups were similar. In Sapporo group TAA was positive in 6.4% of males and 13.8% of females with an age-related increase. The overall prevalence of hyperthyroidism (TSH < 0.15 mU/L) in coastal group (0.6%) was similar to that in Sapporo group (1.1%), while that of hypothyroidism (TSH > 5.0 mU/L) in coastal group (3.8%) was significantly higher than that in Sapporo group (1.3%) (P < 0.001). The frequency of high UI correlated significantly with that of hypothyroidism with negative TAA (r = 0.829, P < 0.05), but not with positive TAA, or with that of hyperthyroidism. Hypothyroidism was more prevalent in TAA negative subjects with high UI than with normal UI. Moreover, serum TSH and thyroglobulin levels were higher and free T4 level was lower in former than in latter group. These results indicate that 1) the prevalence of TAA negative hypothyroidism in iodine sufficient areas may be associated with the amount of iodine ingested, 2) this hypothyroidism is more prevalent and marked in subjects consuming further excess amounts of iodine, and 3) excessive intake of iodine should be considered an etiology of hypothyroidism in addition to chronic thyroiditis in these areas.