Biomedical subjects

K Takeuchi

Publications and source records attributed to K Takeuchi.

At least 127 records · Page 7Linked to original sources

PubMed2001

Lack of gastric toxicity of nitric oxide-releasing indomethacin, NCX-530, in experimental animals.

The effects of a nitric oxide (NO) releasing derivative of indomethacin (NCX-530) on gastric ulcerogenic and healing responses were evaluated in rats and mice, in comparison with the parent compound indomethacin. Indomethacin (per os) produced damage in the rat stomach in a dose-dependent manner. NCX-530 (per os) itself, however, was not ulcerogenic and even showed a dose-dependent protection against HCl/ethanol-induced lesions in the rat stomach. Likewise, indomethacin given repeatedly delayed healing of gastric ulcers induced in mice by thermal cauterization, while NCX-530 did not affect the healing response and significantly promoted the healing as compared to indomethacin. These actions of NCX-530 were mimicked by the combined administration of a NO donor NOR-3 with indomethacin. The amount of NO metabolites was increased in both the gastric contents and serum when NCX-530, but not indomethacin, was given in pylorus-ligated stomachs. Neither indomethacin nor NCX-530 influenced gastric acid secretion and transmucosal potential difference, yet NCX-530 caused a marked increase of gastric mucosal blood flow, which was preventable by carboxy-PTIO, a scavenger of NO. Gastric motility was increased by indomethacin but not by NCX-530. In addition, NCX-530 inhibited PGE2 generation in both the intact and ulcerated gastric mucosa and showed antiinflammatory action on carrageenan-induced rat paw edema, as effectively as indomethacin. These results suggest that unlike indomethacin, NCX-530 caused neither an irritating action on the stomach nor healing impairment effect on the preexisting gastric ulcers, but conferred gastric protection against HCl/ethanol, despite causing cyclooxygenase inhibition and antiinflammatory action, as effectively as indomethacin. This NO-releasing indomethacin, probably by releasing NO, exerts protective influences, such as an increase of gastric mucosal blood flow, that counteract the potential damaging effects of cyclooxygenase inhibition by indomethacin.

Acetates↗

PubMed2001

Effect of diltiazem on cardiac function assessed by echocardiography and neurohumoral factors after reperfused myocardial infarction without congestive heart failure.

The purpose of this study was to examine the effect of diltiazem on cardiac function and neurohumoral factors (BNP, epinephrine, norepinephrine) after reperfused myocardial infarction without congestive heart failure (Killip class I). On the first day after myocardial infarction following reperfusion therapy patients were randomly assigned to diltiazem treatment (group 1, n=33) or no treatment (group 2, n=39). We then performed echocardiographic examinations on the patients and measured heart rate, mean blood pressure and neurohormones (BNP, epinephrine and norepinephrine). Follow-up evaluations of echocardiography were performed at 4 and 12 weeks and of neurohormones at 1 and 4 weeks after acute myocardial infarction. The highest peaks of plasma BNP, epinephrine, and norepinephrine levels were observed before treatment and decreased with time in both groups. After 4 weeks the level of plasma BNP in the diltiazem treatment group was lower than in the no treatment group [55+/-3 pg/mL vs 85+/-5 pg/mL (P < 0.05)]. Other neurohormones did not differ between groups. Fractional shortening (FS) and ejection fraction (EF)improved after myocardial infarction in both groups, but significantly more in the diltiazem group (P < 0.05) after 12 weeks of treatment. Changes in BNP correlated significantly with changes in left ventricular end systolic volumes, FS and EF. In this study, diltiazem significantly improved systolic function and reduced the level of plasma BNP after myocardial infarction, which suggest that diltiazem may have a beneficial effect on myocardial infarction without congestive heart failure.

Aged↗

PubMed2001

Lack of small intestinal ulcerogenecity of nitric oxide-releasing indomethacin, NCX-530, in rats.

AIM: To evaluate the intestinal ulcerogenic property of nitric oxide-releasing indomethacin (NCX-530) in the rat, in comparison with indomethacin. METHODS: Animals were given indomethacin or NCX-530 subcutaneously and killed 24 h later for macroscopic examination of the small intestine. RESULTS: A single administration of indomethacin (10 mg/kg) provoked damage, mainly in the jejunum and ileum, accompanied by an increase in myeloperoxidase and inducible nitric oxide synthase activities as well as bacterial translocation. NCX-530 at an equimolar dose (14.2 mg/kg) caused no gross damage in the small intestine, nor any significant change in inducible nitric oxide synthase and myeloperoxidase activities or bacterial translocation. NOR-3, the nitric oxide donor (6.0 mg/kg), when administered subcutaneously together with indomethacin, significantly prevented the occurrence of intestinal lesions and other mucosal changes. Indomethacin reduced mucus and fluid secretions in the small intestine, while both NCX-530 and NOR-3 enhanced these secretions. NCX-530 reduced the mucosal prostaglandin E2 contents and exhibited an anti-inflammatory action against carrageenan-induced paw oedema, with equal effectiveness to indomethacin. CONCLUSION: NCX-530 does not cause intestinal damage, despite inhibiting cyclooxygenase activity. The reduced intestinal toxicity of NCX-530 may be attributable to inhibition of enterobacterial translocation, partly by increasing the mucus and fluid secretions mediated by nitric oxide released from this compound.

Acetates↗

PubMed2001

Anticonvulsant hypersensitivity syndrome associated with reactivation of cytomegalovirus.

Recently, it has been proposed that viral infection is involved in the pathogenesis of hypersensitivity syndrome. Cytomegalovirus (CMV), one of the aetiological agents of infectious mononucleosis, has never been reported as an organism associated with hypersensitivity syndrome. We describe a 64-year-old man with severe phenytoin-induced hypersensitivity syndrome associated with CMV infection. Twenty-five days after the patient was started on phenytoin, he developed high fever and a generalized erythematous rash followed by jaundice, renal failure and disseminated intravascular coagulopathy (DIC). CMV-specific IgG antibodies were significantly increased 7 weeks after the onset of clinical symptoms and the increase was associated with the appearance of CMV-specific IgM. CMV DNA was detected in the serum of the patient. Coinfection with other viruses, such as Epstein-Barr virus and human herpesviruses 6 and 7, could be excluded because antibody titres to those viruses did not increase during the clinical course of his illness. We suggest that reactivation of CMV may contribute, at least in some cases, to the development of hypersensitivity syndrome.

Anticonvulsants↗

PubMed2001

Marked decrease in the Epstein-Barr virus positivity rate in nodular sclerosis subtype Hodgkin's disease in Tokyo: trend between 1955 and 1999.

We studied the trends of the Epstein-Barr virus (EBV) positivity rate in Hodgkin's disease (HD) between 1955 and 1999. The overall positivity rate gradually decreased over time [12 out of 23 (52%) in 1955-69; 18 out of 39 (46%) in 1970-84; 13 out of 44 (35%) in 1985-99; P = 0.135]. Interestingly, a marked decrease in the rate was noted in the nodular sclerosis (NS) subtype [5 out of 11 (45%); 4 out of 19 (21%); 1 out of 24 (4%); P < 0.01] but not in other classic HD [7 out of 11 (63%); 14 out of 18 (78%); 12 out of 18 (67%); P = 0.775]. Our results indicate that the EBV positivity rate in HD has decreased over time and that this trend reflected the increasing incidence of EBV-negative NS.

Adaptor Proteins, Signal Transducing↗

PubMed2001

Sendai virus C protein physically associates with Stat1.

BACKGROUND: The P/C gene of the Sendai virus (SeV), a member of the family Paramyxoviridae, encodes C protein, which plays a crucial role in counteracting the antiviral effect of interferon (IFN). The C protein blocks IFN signalling to prevent the activation of IFN stimulated genes. However, its underlying molecular mechanism remains to be defined. RESULTS: Signal transducer and activator of transcription 1 (Stat1) is a critical component of IFN-alpha/beta and IFN-gamma signalling. We found that both unphosphorylated Stat1 and tyrosine-phosphorylated (pY) Stat1 were present in a form of aberrant high molecular weight complexes (HMWCs) of over 2 MDa in infected cell extracts under low-salt conditions. Of recombinant vaccinia viruses carrying each SeV gene, only those expressing the C gene induced Stat1-HMWC. SeV infected cell extracts further displayed an in vitro ability to convert the pY-Stat1 homodimer to pY-Stat1-HMWC. This cell extract activity was not seen after removal of the C protein from the extracts. C protein was therefore involved in the formation of HMWCs. The HMWCs decomposed into smaller complexes in a high-salt buffer, and under this stringent (high-salt) condition, as well as a physiological (isotonic) condition, both unphosphorylated Stat1 and pY-Stat1 were co-precipitated with anti-C antibody. CONCLUSION: The C protein physically associates with Stat1. This suggests that SeV C protein directly targets Stat1 for inhibitory control on the transcriptional activation of IFN stimulated genes.

DNA-Binding Proteins↗

PubMed2001

Effect of 9-(6,7-dideoxy-beta-D-allo-hept-5-ynofuranosyl)adenine on noradrenaline release from vascular sympathetic nerves.

1. The effects of 9-(6,7-dideoxy-beta-D-allo-hept-5-ynofuranosyl)adenine (HAK2701), a selective and potent ligand for P3 receptor-like protein, on the release of endogenous noradrenaline (NA) from electrically stimulated rat mesenteric artery and rabbit ear artery were compared with those of a number of purinoceptor agonists. 2. In the rat mesenteric artery, the P1 receptor agonists 2-chloroadenosine (2CA) and 5'-N-ethylcarboxamidoadenosine (NECA) and the P2 purinoceptor agonists beta,gamma-methylene ATP (betagammamATP) and 2-methylthio ATP (2mSATP) significantly inhibited the release of NA in a xanthine-sensitive manner. HAK2701 did not significantly inhibit the release of NA, the relative order of potency being betagammamATP > NECA > 2CA > 2mSATP >> HAK2701. 3. In the rabbit ear artery, both P1 and P2 receptor agonists significantly facilitated the release of NA in a xanthine-sensitive manner. HAK2701 also significantly facilitated the release of NA, the relative order of potency being HAK2701 > betagammamATP > 2CA > 2mSATP > NECA. 4. These findings suggest that HAK2701 may be a potent and selective agonist for facilitatory prejunctional purinoceptors, but not for inhibitory purinoceptors, on adrenergic nerve terminals.

2-Chloroadenosine↗

PubMed2001

Monochloramine impairs mucosal blood flow response and healing of gastric lesions in rats: relation to capsaicin-sensitive sensory neurons.

AIMS: We examined the effects of monochloramine (NH2Cl) on the gastric mucosal blood flow (GMBF) response and the healing of ethanol-induced gastric lesions in rats. METHODS: Rats fasted for 18 h were given the 99% ethanol p.o. for induction of gastric lesions, and were fed normally from 1 h later onwards. Monochloramine, at non-ulcerogenic doses (5 to approximately 20 mmol/L), was given p.o. twice daily for 7 days, starting 2 h after ethanol treatment. RESULTS: Gastric lesions caused by ethanol healed almost completely within 7 days with re-epithelialization. The repeated administration of NH2Cl significantly delayed the healing of ethanol-induced gastric lesions in a dose-dependent manner. The damaged mucosa showed a marked rise in H+ permeability, resulting in luminal acid loss, but this process was accompanied by an increase of mucosal blood flow. Monochloramine did not affect the increased mucosal H+ permeability observed in the stomach after damage by ethanol, but significantly inhibited the mucosal hyperemic response associated with luminal acid loss. Prior exposure of the mucosa to NH2Cl (20 mmol/L) did not affect the gastric hyperemic response caused by mucosal application of misoprostol (a prostaglandin E1 derivative) or NOR-3 (a nitric oxide donor), but totally attenuated the increase of GMBF in response to intragastric capsaicin. Impaired healing and GMBF responses were also observed in rats following chemical ablation of capsaicin-sensitive sensory neurons. CONCLUSIONS: These results suggest that NH2Cl impaired the healing of acute gastric mucosal lesions at low concentrations, and this action may be attributable, at least partly, to the impairment of gastric hyperemic response caused by the dysfunction of capsaicin-sensitive sensory neurons.

Afferent Pathways↗

PubMed2001

Polymorphic expression of decay-accelerating factor in human colorectal cancer.

BACKGROUND: We have previously shown that expression of decay-accelerating factor (DAF), a complement regulatory protein, is enhanced immunohistochemically on the luminal surface of cancer glands in human colorectal cancer and is detected in stool specimens of patients with colorectal cancer. The amount of DAF present in the stools might be influenced by the stability of DAF on the cell surface which is regulated by biochemical properties such as glycosylation of the protein. In the present study, to help elucidate the mechanism for the release of DAF from human colorectal cancers, we biochemically analyzed DAF expression by western and northern blotting by using surgically resected specimens of colorectal cancers. METHODS: Surgically resected colorectal cancer tissues were obtained from 10 patients. Expression of DAF was determined by western and northern blotting, and glycosylation of DAF protein was analyzed with glycosidase digestion. RESULTS: Northern blot analysis demonstrated that the expression of DAF mRNA in colorectal cancer was enhanced two- to threefold compared with normal tissues. In western blotting, expression of DAF protein in the cancer tissue was increased, and heterogeneity in the apparent molecular weight of DAF was observed among patients. When o-linked sugars were removed, this heterogeneity of DAF size diminished. CONCLUSIONS: The polymorphic expression of DAF in colorectal cancer is likely to reflect variability in the o-glycosylation of the protein. We speculate that this variability could affect the stability of DAF on the surfaces of cancer cells and, in turn, the amount of DAF shed into the stools of colorectal cancer patients.

Adult↗

PubMed2001

Macrocystic type of serous cystadenoma with a communication between the cyst and pancreatic duct.

A 42-year-old woman with a cystic lesion in the head of the pancreas was evaluated by using abdominal ultrasonography, a computed tomographic scan, magnetic resonance imaging and endoscopic retrograde pancreatography. Multiple cystic lesions, 5 cm in diameter, which had papillary protrusion inside the cyst in the head of the pancreas and had the communication between the cysts and pancreatic duct, were determined. Pylorus-preserving pancreaticoduodenectomy was performed under the diagnosis of mucinous cystic neoplasm of the pancreas. Although the cut surface of the tumor showed a macrocystic tumor of 3 cm in diameter, part of the cyst wall was cavernous. A histopathological examination showed single-layered cuboidal cells, which lead to the diagnosis as being serous cystadenoma of the pancreas. Serous cystadenoma is a rare, almost benign pancreatic tumor. The macrocystic subtype of serous cystadenoma is even more rare. We describe a patient who had this macrocystic subtype of serous cystadenoma with a communication between the cyst and pancreatic duct. This case illustrates the difficulty in the diagnosis of cystic lesions in the pancreas, and might support the single category of cystic lesions of the pancreas.

Adult↗

PubMed2001

Role of UGT1A1 mutation in fasting hyperbilirubinemia.

BACKGROUND AND AIM: Low-grade fasting hyperbilirubinemia is a common observation in healthy subjects (HS), whereas high-grade fasting hyperbilirubinemia is believed to be a characteristic finding of Gilbert's syndrome. This study was undertaken to assess the role of mutation in bilirubin UDP- glycosyltransferase gene (UGT1A1) on fasting hyperbilirubinemia. METHODS: Analysis of UGT1A1 and a caloric restriction test (400 kcal for 24 h) were performed in 56 healthy subjects (25 males, 31 females), and 28 patients with Gilbert's syndrome (18 males, 10 females). There were 29 healthy subjects with no mutation in UGT1A1, and 27 healthy subjects and 26 Gilbert's syndrome patients with mutations in the coding and/or promoter (TATA box) regions of UGT1A1. RESULTS: The mean increment of serum bilirubin (DeltaSB) was 7.6 micromol/L [corrected] (males) and 4.1 micromol/L (females) in subjects with no UGT1A1 mutation. Subjects with mutation in UGT1A1 showed higher levels of DeltaSB than individuals without mutation. Among healthy subjects, gender difference in DeltaSB values was observed only in individuals with the wild type of UGT1A1, but not in those with mutations in this gene. CONCLUSION: The results of the present study suggest that UGT1A1 mutation has a role in the development of high-grade fasting hyperbilirubinemia after caloric restriction.

Adult↗

PubMed2001

Protective effect of rebamipide on indomethacin-induced intestinal damage in rats.

BACKGROUND AND AIM: We evaluated the effect of rebamipide (2-(4-chlorobenzoylamino)-3-[2(1H)-quinolinon-4-yl] propionic acid), a novel anti-ulcer drug, on indomethacin-induced small intestinal lesions in rats. METHODS: The animals were administered indomethacin (10 mg/kg, s.c.), and they were killed 24 h later. Rebamipide (30-300 mg/kg) was administered p.o. twice, 30 min before, and 6 h after indomethacin. RESULTS: Indomethacin caused hemorrhagic lesions in the rat small intestine, accompanied by an increase in enterobacterial translocation, inducible nitric oxide synthase (iNOS) and myeloperoxidase (MPO) activities, as well as thiobarbituric acid (TBA) reactants, and these changes were significantly prevented by the supplementation with 16,16-dimethyl prostaglandin E2 (dmPGE2; 10 microg/kg, i.v.) or the pretreatment of animals with the antibiotic ampicillin. Treatment of the animals with rebamipide dose-dependently prevented the development of intestinal lesions, and this effect was mimicked by i.v. administration of superoxide dismutase (SOD: 3000 U/kg) + catalase (CAT: 5000 U/kg). The protection by rebamipide was accompanied by a significant suppression of the increase in both MPO and iNOS activities, and a complete inhibition of the increase in TBA reactants, while SOD + CAT significantly inhibited the increase of MPO activity and TBA reactants, but not iNOS activity. The bacterial translocation following indomethacin was also significantly decreased by either rebamipide or SOD + CAT. CONCLUSION: These results confirmed the importance of enterobacteria and iNOS/NO in the pathogenesis of indomethacin-induced small intestinal lesions, and suggested that rebamipide prevents the development of these lesions, probably by its radical scavenging action.

Alanine↗

PubMed2001

Contingent negative variation in children with orthostatic dysregulation.

BACKGROUND: Children with orthostatic dysregulation (OD) appear to have hypodynamia, as well as the symptoms described in the OD criteira. Hypodynamia, which is greatly influenced by motivation, volition and concentration, is unexceptionally recognized in their everyday life. It has been suggested that the symptoms and hypodynamia aggravate considerably the quality of life (QOL) of children with OD. The purpose of this study was to distinguish the characteristics of contingent negative variation (CNV) and post imperative negative variation, which may reflect the level of attention and motivation in children with OD. METHODS: Twelve patients with OD aged 10-15 years and 23 age-matched healthy children were included. The CNV was recorded from Fz, Cz and Pz linked to earlobes during 30 trials consisting of a warning stimulus and an imperative stimulus with an interstimulus interval (ISI) of 2 s and an intertrial interval (ITI) of 10 s. The imperative stimulus of each trial required a button to be pressed. RESULTS: The untreated children with OD did not have a significantly smaller CNV amplitude than healthy children. Children with OD treated with midodrine and autonomic training had a significantly larger CNV amplitude than the untreated children, in the area of early, late and total CNV at the three sites. CONCLUSION: The present study confirms that children with OD have diminished motivation and deterioration of concentration, which cause hypodynamia in everyday life. Treatment for OD improves the symptoms, diminished motivation and deterioration of concentration, consequently restoring dynamia. Treatment for OD should be recommended to ameliorate QOL of children with OD.

Adolescent↗

PubMed2001

Histamine alters gene expression in cultured human nasal epithelial cells.

BACKGROUND: Airway epithelial cells produce cytokines and participate in the regulation of mucosal immunity. Although nasal epithelial cells express histamine receptors, it is not exactly known how nasal epithelial cells respond to histamine. OBJECTIVE: The objective of this study was to examine whether histamine can alter the expression of the 4 genes encoding H1 receptor, IL-8, TNF-alpha, and ZO-1 tight-junction protein in cultured nasal epithelial cells. METHODS: We added histamine or vehicle to cultured human nasal epithelial cells and extracted RNA from them 4 hours later. After DNase treatment, mRNAs of beta-actin, H1 receptor, IL-8, TNF-alpha, and ZO-1 tight-junction protein were amplified by using RT-PCR. RESULTS: Histamine significantly upregulated IL-8 mRNA expression and significantly downregulated ZO-1 mRNA expression. The latter effect was blocked by pretreatment with mepyramine, an H1 receptor antagonist. CONCLUSION: The reduction of ZO-1 mRNA by histamine may cause increased permeability of the mucosa during allergic reactions in the nose.

Cells, Cultured↗

PubMed2001

Epidermal growth factor induces expression of decay-accelerating factor in human colonic cancer cells via the mitogen-activated protein kinase pathway.

The expression of decay-accelerating factor (DAF), a complement regulatory protein, is enhanced in colorectal cancer. In this study, to elucidate mechanisms for enhanced DAF expression, we studied the effects of growth factors on DAF expression in HT-29 human colonic cancer cells. Cells were treated with epidermal growth factor (EGF), insulin-like growth factor-I, platelet-derived growth factor, and transforming growth factor-beta. DAF protein expression and mRNA expression were determined with enzyme immunoassay and Northern blot analysis. The signaling pathways that target DAF expression in response to growth factor stimulation were characterized by using various inhibitors of the signal transduction pathway. EGF induced significant increases in DAF protein and mRNA expression in HT-29 cells; the other growth factors had a weak effect or no effect. The EGF-induced DAF expression was inhibited by mitogen-activated protein (MAP) kinase kinase inhibitor PD 98059 but not by phosphatidylinositol-3 kinase inhibitor, phospholipase Cgamma inhibitor, or protein kinase C inhibitor. When we analyzed the phosphorylation state of the MAP kinase by immunoblot analysis, phosphorylated p44/p42 MAP kinase was detected in EGF-stimulated HT-29 cells, and the addition of PD 98059 abrogated the phosphorylation. These results indicate that EGF regulates DAF expression in HT-29 cells via the signaling pathway that depends on the activation of MAP kinase.

Blotting, Northern↗

PubMed2001

The prognostic value of natural killer cell infiltration in resected pulmonary adenocarcinoma.

OBJECTIVE: Natural cytotoxicity caused by mediated natural killer cells is believed to play an important role in host-cancer defense mechanisms. Immunohistochemically, we have detected natural killer cells in tissue specimens from patients with pulmonary adenocarcinoma and have assessed their clinical characteristics. METHODS: Using the monoclonal antibody for CD57 specific marker for natural killer cells, we quantified natural killer cell infiltration in 150 patients with pulmonary adenocarcinoma who underwent curative tumor resection to investigate the relationship between natural killer cell counts and clinicopathologic factors and prognosis. RESULTS: The natural killer cell count was significantly related to the regulation of tumor progression, involving T classification, N classification, and stage (P =.01 for T classification or stage; P =.02 for N classification). A significant difference in the rate of patient survival was detected between those patients whose tumors had either high or low natural killer cell counts in both the overall and stage I groups (P =.0002 for the overall group; P =.049 for the stage I group). CONCLUSION: These data indicate that natural killer infiltration may contribute to the regulation of tumor progression and that the natural killer cell count can serve as a useful prognostic marker in overall and stage I pulmonary adenocarcinoma.

Adenocarcinoma↗

PubMed2001

Clinical studies of enteritis caused by methicillin-resistant Staphylococcus aureus.

OBJECTIVE: To study the clinical features of methicillin-resistant Staphylococcus aureus (MRSA) enteritis in our surgical ward. DESIGN: Retrospective study. SETTING: Teaching hospital, Japan. SUBJECTS: 16 men and 1 woman who developed MRSA enteritis from January 1995 to October 1999. MAIN OUTCOME MEASURES: Causes and treatments. RESULTS: The underlying diseases were as follows: gastric cancer (n = 13), colorectal cancer (n = 2), recurrent cancer (n = 1) and bowel obstruction following gastrectomy (n = 1). 16 patients were operated on. Two cases were treated with histamine H2 receptor blockers. The mean age of patients was 65 years (range 50-80). In 13 cases MRSA enteritis developed within 6 days of operation. 10 strains of MRSA were isolated from stools, 8 from gastric juice, and 3 from intra-abdominal exudate. 10 patients were treated with vancomycin given through a nasogastric tube and 2 through a nasogastric tube and by drip intravenous infusion. 15 patients survived and 2 died. CONCLUSIONS: Patients who are given broad-spectrum antibiotics and whose gastric secretion is reduced are at high risk of MRSA enteritis. In the surgical ward, early diagnosis, treatment, and isolation are essential for patients with MRSA enteritis.

Aged↗

PubMed2001

Identification and characterization of an antibacterial peptide of the 26-kDa protease of Sarcophaga peregrina with antibacterial activity.

Previously, we purified a serine protease with a molecular mass of 26 kDa that exhibits potent antibacterial activity from a pupal extract of Sarcophaga peregrina (flesh fly). We divided this protease into 12 peptides and examined their antibacterial activity. A peptide corresponding to residues 155 to 174 (peptide 9) was found to exhibit antibacterial activity comparable to that of the 26-kDa protease. When Escherichia coli was treated with peptide 9, the permeability of both the outer and inner membranes increased, and substrates for beta-lactamase and beta-galactosidase entered the cells, but beta-galactosidase did not leak out of the cells under these conditions. It was suggested that residues 6 to 18 of peptide 9 form an amphiphilic alpha-helix under hydrophobic conditions with an N-terminal basic loop and then interact with acidic phospholipids in the bacterial membranes.

Amino Acid Sequence↗