Antimicrobial peptides for therapeutic applications: a review

Antimicrobial peptides (AMPs) have been considered as potential therapeutic sources of future antibiotics because of their broad-spectrum activities and different mechanisms of action compared to conventional antibiotics. Although AMPs possess considerable benefits as new generation antibiotics, their clinical and commercial development still have some limitations, such as potential toxicity, susceptibility to proteases, and high cost of peptide production. In order to overcome those obstacles, extensive efforts have been carried out. For instance, unusual amino acids or peptido-mimetics are introduced to avoid the proteolytic degradation and the design of short peptides retaining antimicrobial activities is proposed as a solution for the cost issue. In this review, we focus on small peptides, especially those with less than twelve amino acids, and provide an overview of the relationships between their three-dimensional structures and antimicrobial activities. The efforts to develop highly active AMPs with shorter sequences are also described.

The Arabidopsis aldehyde oxidase 3 (AAO3) gene product catalyzes the final step in abscisic acid biosynthesis in leaves

Abscisic acid (ABA) is a plant hormone involved in seed development and germination and in responses to various environmental stresses. The last step of ABA biosynthesis involves oxidation of abscisic aldehyde, and aldehyde oxidase (EC ) is thought to catalyze this reaction. An aldehyde oxidase isoform, AOdelta, encoded by AAO3, one of four Arabidopsis aldehyde oxidase genes (AAO1, AAO2, AAO3, and AAO4), is the most likely candidate for the enzyme, because it can efficiently catalyze the oxidation of abscisic aldehyde to ABA. Here, we report the isolation and characterization of an ABA-deficient Arabidopsis mutant that maps at the AAO3 locus. The mutant exhibits a wilty phenotype in rosette leaves, but seed dormancy is not affected. ABA levels were significantly reduced in the mutant leaves, explaining the wilty phenotype in rosettes, whereas the level in the mutant seeds was less reduced. No AOdelta activity could be detected in the rosette leaves of the mutant. Sequence data showed that the mutant contains a G to A substitution in the AAO3 gene. The mutation causes incorrect splicing of the ninth intron of AAO3 mRNA. We thus conclude that the ABA-deficient mutant is impaired in the AAO3 gene and that the gene product, AOdelta, is an aldehyde oxidase that catalyzes the last step of ABA biosynthesis in Arabidopsis, specifically in rosette leaves. Other aldehyde oxidases may be involved in ABA biosynthesis in other organs.

Higher activity of an aldehyde oxidase in the auxin-overproducing superroot1 mutant of Arabidopsis thaliana

Aldehyde oxidase (AO; EC 1.2.3.1) activity was measured in seedlings of wild type or an auxin-overproducing mutant, superroot1 (sur1), of Arabidopsis thaliana. Activity staining for AO after native polyacrylamide gel electrophoresis separation of seedling extracts revealed that there were three major bands with AO activity (AO1-3) in wild-type and mutant seedlings. One of them (AO1) had a higher substrate preference for indole-3-aldehyde. This AO activity was significantly higher in sur1 mutant seedlings than in the wild type. The difference in activity was most apparent 7 d after germination, the same time required for the appearance of the remarkable sur1 phenotype, which includes epinastic cotyledons, elongated hypocotyls, and enhanced root development. Higher activity was observed in the root and hypocotyl region of the mutant seedlings. We also assayed the indole-3-acetaldehyde oxidase activity in extracts by high-performance liquid chromatography detection of indole-3-acetic acid (IAA). The activity was about 5 times higher in the extract of the sur1 seedlings, indicating that AO1 also has a substrate preference for abscisic aldehyde. Treatment of the wild-type seedlings with picloram or IAA caused no significant increase in AO1 activity. This result suggested that the higher activity of AO1 in sur1 mutant seedlings was not induced by IAA accumulation and, thus, strongly supports the possible role of AO1 in IAA biosynthesis in Arabidopsis seedlings.

Abscisic aldehyde oxidase in leaves of Arabidopsis thaliana

Abscisic acid (ABA) is a plant hormone involved in seed development and responses to various environmental stresses. Oxidation of abscisic aldehyde is the last step of ABA biosynthesis and is catalysed by aldehyde oxidase (EC 1.2.3.1). We have reported the occurrence of three isoforms of aldehyde oxidase, AOalpha, AObeta and AOgamma, in Arabidopsis thaliana seedlings, but none oxidized abscisic aldehyde. Here we report a new isoform, AOdelta, found in rosette leaf extracts, which efficiently oxidizes abscisic aldehyde. AO delta was specifically recognized by antibodies raised against a recombinant peptide encoded by AAO3, one of four Arabidopsis aldehyde oxidase genes (AAO1, AAO2, AAO3 and AAO4). Functionally expressed AAO3 protein in the yeast Pichia pastoris showed a substrate preference very similar to that of rosette AOdelta. These results indicate that AOdelta is encoded by AAO3. AOdelta produced in P. pastoris exhibited a very low Km value for abscisic aldehyde (0.51 microM), and the oxidation product was determined by gas chromatography-mass spectrometry to be ABA. Northern analysis showed that AAO3 mRNA is highly expressed in rosette leaves. When the rosette leaves were detached and exposed to dehydration, AAO3 mRNA expression increased rapidly within 3 h of the treatment. These results suggest that AOdelta, the AAO3 gene product, acts as an abscisic aldehyde oxidase in Arabidopsis rosette leaves.

Differential expression of two members of FGF receptor gene family, FGFR-1 and FGFR-2 mRNA, in the adult rat central nervous system

The fibroblast growth factor (FGF) receptor gene family now contains four members that encode homologous receptor-tyrosine kinases (RTKs) to each other. We have demonstrated that one of the members, FGFR-1 (also termed as flg), is expressed in the widespread but specific neuronal populations in the adult rat central nervous system (CNS). In the present study, we examined the expression pattern of another member, FGFR-2 (also termed as bek) and compared it with that of FGFR-1. In contrast with FGFR-1, we detected FGFR-2 expression primarily in the fiber tracts of the adult rat CNS, suggesting that the oligodendrocytes are the main sites of the FGFR-2 expression. These findings indicate that FGF may regulate neurons and glial cells through different subtypes of its cognate receptor.

HaCaT Keratinocytes and Primary Epidermal Keratinocytes Have Different Transcriptional Profiles of Cornified Envelope-Associated Genes to T Helper Cell Cytokines

HaCaT cells are the immortalized human keratinocytes and have been extensively used to study the epidermal homeostasis and its pathophysiology. T helper cells play a role in various chronic dermatological conditions and they can affect skin barrier homeostasis. To evaluate whether HaCaT cells can be used as a model cell system to study abnormal skin barrier development in various dermatologic diseases, we analyzed the gene expression profile of epidermal differentiation markers of HaCaT cells in response to major T helper (Th) cell cytokines, such as IFNγ, IL-4, IL-17A and IL-22. The gene transcriptional profile of cornified envelope-associated proteins, such as filaggrin, loricrin, involucrin and keratin 10 (KRT10), in HaCaT cells was generally different from that in normal human keratinocytes (NHKs). This suggests that HaCaT cells have a limitation as a model system to study the pathophysiological mechanism associated with the Th cell cytokine-dependent changes in cornified envelope-associated proteins which are essential for normal skin barrier development. In contrast, the gene transcription profile change of human β2-defensin (HBD2) in response to IFNγ, IL-4 or IL-17A in HaCaT cells was consistent with the expression pattern of NHKs. IFNγ also up-regulated transglutaminase 2 (TGM2) gene transcription in both HaCaT cells and NHKs. As an alternative cell culture system for NHKs, HaCaT cells can be used to study molecular mechanisms associated with abnormal HBD2 and TGM2 expression in response to IFNγ, IL-4 or IL-17A.

Expression of the fibroblast growth factor family and their receptor family genes during mouse brain development

The fibroblast growth factor (FGF) family is composed of nine members and four genes encode protein tyrosine kinase receptors for them. To gain insight into the involvement of FGFs and their receptors in the development of nervous system, their expression in brains of perinatal and adult mice was examined by semi-quantitative reverse transcription-linked polymerase chain reactions and in situ hybridization. Although all the genes, with the exception of FGF-4, were found to be expressed, FGF-3, FGF-6, FGF-7 and FGF-8 genes demonstrated higher expression in the late embryonic stages than in postnatal stages, suggesting that these members are involved in the late stages of brain development. In contrast, expression of FGF-1 and FGF-5 increased after birth. Interestingly, FGF-6 expression in perinatal mice was restricted to the central nervous system and skeltal muscles, with intense signals in the developing cerebrum in embryos but in cerebellum in 5-day-old neonates. Furthermore, FGF-receptor (FGFR)-4, a cognate receptor for FGF-6, demonstrated similar spatiotemporal expression, suggesting that FGF-6 and FGFR-4 plays significant roles in the maturation of nervous system as a ligand-receptor system. The results indicate that individual member of the fibroblast growth factor and their receptor family are expressed either sequentially or simultaneously in brain development, strongly suggesting their involvement in the regulation of a variety of developmental processes of brain, i.e., proliferation and migration of neuronal progenitor cells, neuron and glia differentiation, neurite extensions, and synapse formations.

Molecular cloning and characterization of aldehyde oxidases in Arabidopsis thaliana

Using degenerate primers designed by deduced amino acid sequences of known aldehyde oxidases (AO) from maize and bovine, two independent cDNA fragments were amplified by reverse transcription-polymerase chain reaction (PCR). The two corresponding full-length cDNAs (atAO-1 and atAO-2; 4,484 and 4,228 bp long, respectively) were cloned by screening the Arabidopsis cDNA library followed by rapid amplification of cDNA end-PCR. These cDNAs are highly homologous at both the nucleotide and amino acid sequence levels, and the deduced amino acid sequences showed high similarity with those of maize and tomato AOs. They contain consensus sequences for two iron-sulfur centers and a molybdenum cofactor (MoCo)-binding domain. In addition, another cDNA having a sequence similar to that of the cDNAs was screened (atAO-3; 3,049 bp), and a putative AO gene (AC002376) was reported on chromosome 1, which (atAO-4) was distinct from, but very similar to, the above three AOs. atAO-1, 2, 3, and 4 were physically mapped on chromosomes 5, 3, 2 and 1, respectively. These data indicate that there is an AO multigene family in Arabidopsis. atAO-1 protein was shown to be highly similar to one of the maize AOs in respect to a region thought to be involved in determination of substrate specificity, suggesting that they might encode a similar type of AO, which could efficiently oxidize indole-3-acetaldehyde to indole-3-acetic acid (IAA). atAO-1 and atAO-2 genes were expressed at higher levels in lower hypocotyls and roots of the wild-type seedlings, while atAO-3 was slightly higher in cotyledons and upper hypocotyls. The expression of atAO-1 was more abundant in the seedlings of an IAA overproducing mutant (superroot1; sur1) than in those of wild type. atAO-2 and atAO-3 transcripts were rather evenly distributed in these seedlings. A possible involvement of atAO genes in phytohormone biosynthesis in Arabidopsis is discussed.

Cloning and molecular characterization of plant aldehyde oxidase

Primary structural information of a plant aldehyde oxidase (AO), which was purified from maize coleoptiles using indole-3-acetaldehyde as a substrate, was obtained by sequencing a series of cleavage peptides, permitting the cloning of the corresponding cDNA (zmAO-1). The complete nucleotide sequence was determined; the deduced amino acid sequence encodes a protein of 1358 amino acid residues of Mr 146,681, which is consistent with the size of the AO monomeric subunit. There is a significant similarity with AO from mammals and xanthine dehydrogenases from various sources. The maize AO polypeptide contains consensus sequences for iron-sulfur centers and a putative molybdopterin cofactor-binding domain. In addition, another cDNA (zmAO-2), highly homologous to zmAO-1 at both the nucleotide and amino acid sequence levels, was cloned. zmAO-2 would encode a protein of 1349 amino acid residues of Mr 145,173 and has molecular characteristics similar to those of zmAO-1. zmAO-1 was expressed at a high level in roots, which was closely correlated with immunoblotting results using antiserum raised against the purified maize AO protein, whereas zmAO-2 was expressed at a higher level in coleoptiles than in roots. We propose each zmAO may have a unique function during plant development.

Telling the diagnosis to cancer patients in Japan: attitude and perception of patients, physicians and nurses

The aim of this study was to clarify patients', physicians', and nurses' perceptions with regard to the communication of diagnosis to cancer patients in Japan. Sixty-three cancer patients, 35 physicians and 21 nurses were enrolled for this study: 54 of the patients wished to be informed of the diagnosis, of whom 34 had actually been told that they had cancer. Physicians did not tell the truth to the remaining 20 patients, of whom seven were not told the diagnosis because family members objected. Twenty-one of the 35 physicians thought that telling the true diagnosis had a positive effect and 27 thought that disclosure of the diagnosis to cancer patients should be promoted. Sixteen of the 21 nurses did not experience any difficulties with patient care after the diagnosis was disclosed. The present study suggests that medical staff and family members should respect the patient's standpoint because patients have the right to know about their own condition. Physicians should first provide the details of the disease to their patients. Thereafter, family members should be informed, but only with the patient's consent.

Systematic Peptide Engineering and Structural Characterization to Search for the Shortest Antimicrobial Peptide Analogue of Gaegurin 5

As part of an effort to develop new, low molecular mass peptide antibiotics, we searched for the shortest bioactive analogue of gaegurin 5 (GGN5), a 24-residue antimicrobial peptide. Thirty-one kinds of GGN5 analogues were synthesized, and their biological activities were analyzed against diverse microorganisms and human erythrocytes. The structural properties of the peptides in various solutions were characterized by spectroscopic methods. The N-terminal 13 residues of GGN5 were identified as the minimal requirement for biological activity. The helical stability, the amphipathic property, and the hydrophobic N terminus were characterized as the important structural factors driving the activity. To develop shorter antibiotic peptides, amino acid substitutions in an inactive 11-residue analogue were examined. Single tryptophanyl substitutions at certain positions yielded some active 11-residue analogues. The most effective site for the substitution was the hydrophobic-hydrophilic interface in the amphipathic helical structure. At this position, tryptophan was the most useful amino acid conferring favorable activity to the peptide. The introduced tryptophan played an important anchoring role for the membrane interaction of the peptides. Finally, two 11-residue analogues of GGN5, which exhibited strong bactericidal activity with little hemolytic activity, were obtained as property-optimized candidates for new peptide antibiotic development. Altogether, the present approach not only characterized some important factors for the antimicrobial activity but also provided useful information about peptide engineering to search for potent lead molecules for new peptide antibiotic development.

A new quadruple therapy for Helicobacter pylori: influence of resistant strains on treatment outcome

BACKGROUND

There have been no reports concerning the efficacy and safety of a 1-week quadruple therapy regimen of omeprazole, amoxycillin, roxithromycin and metronidazole for Helicobacter pylori infections and the impact of primary resistance on the eradication rate.

METHODS

One hundred and sixty-nine consecutive patients with peptic ulcer disease as well as gastritis with biopsy-proven H. pylori infection were entered into an open study of omeprazole 20 mg o.m., amoxycillin 500 mg t.d.s., roxithromycin 150 mg b.d., and metronidazole 250 mg t.d.s. Helicobacter pylori status was determined by urease test, histology and culture. Susceptibility to amoxycillin, metronidazole and roxithromycin was determined by the E-test.

RESULTS

H. pylori was eradicated in 155 out of 169 (92%; 95% CI 88-96%) by intention-to-treat analysis, and in 155 out of 163 (95%; 95% CI 92-98%) by per protocol analysis. The prevalence of primary resistance against amoxycillin, roxithromycin and metronidazole was 2 out of 166 (1%), 16 out of 166 (10%) and 27 out of 166 (16%), respectively. H. pylori was eradicated in 25 out of 27 (93%) patients with metronidazole-resistant strains compared with 130 out of 136 (96%) in patients with metronidazole-sensitive strains of H. pylori. It was eradicated in 15 out of 16 (94%) patients with roxithromycin-resistant strains while in 140 out of 147 (95%) patients with roxithromycin-sensitive strains of H. pylori, and in two out of two (100%) patients with amoxycillin-resistant stains compared with 153 out of 161 (95%) in patients with amoxycillin-sensitive strains. H. pylori was eradicated in three out of four (75%) patients with double resistance against metronidazole and roxithromycin compared with 152 out of 159 (96%) patients with sensitive strains to metronidazole and or roxithromycin. None of these differences were statistically significant. Severe side-effects were found in only one out of 169 patients-anaphylaxis due to penicillin.

CONCLUSIONS

The 1-week quadruple therapy with omeprazole, amoxycillin, metronidazole and roxithromycin was found to eradicate H. pylori in over 90% of all patients. This regimen was also found to be beneficial for patients with pre-treatment resistant strains to metronidazole, roxithromycin or amoxycillin, and was observed to be safe and well-tolerated.

Current status of vivax malaria among civilians in Korea

A result of national malaria surveillance in Korean civilians was described. Since a case of indigenous vivax malaria was detected in 1993, a total of 2,198 cases was confirmed by blood smear up to 1997. Of them, 1,548 cases were soldiers serving in the demilitarized zone (DMZ), while 650 cases were civilians. Number of civilian cases was 3 in 1994, 19 in 1995, 71 in 1996, and 557 in 1997. Of them, 239 were ex-soldiers who discharged after military service in the prevalent areas such as Paju, Yonchon, Kimpo, Kangwha, Tongduchon in Kyonggi-do and Chorwon in Kangwon-do while 308 patients were civilian residents in the prevalent areas. Seventy-two patients, living nationwide, had a history of visiting the prevalent areas during transmission season. Only 32 civilian patients denied any relation with the prevalent areas. As a whole, a half of the civilian cases was diagnosed when living in non-prevalent areas. Male patients in their twenties was the highest in number. Annual parasite index is steadily elevated in residents living in the prevalent areas. Monthly incidence showed an unimodal distribution, forming a peak in August. Ex-soldiers exhibited a delayed incubation ranging from 153 to 452 days (279 +/- 41 days). The time required for diagnosis was shortened from 23.6 days in 1995 to 13.7 days in 1997. Although the current epidemic of vivax malaria started as a border malaria, it seems highly probable that vivax malaria is established in the local areas and responsible for at least a part of transmission.

A new quadruple therapy for the eradication of Helicobacter pylori. Effect of pretreatment with omeprazole on the cure rate

To elucidate whether pretreatment with omeprazole decreases the cure rate of Helicobacter pylori infection with a new quadruple therapy, and thus, whether this pretreatment should not be used in clinical practice, we conducted a randomized trial. Ninety patients with chronic peptic ulcer disease and nonulcer dyspepsia, with biopsy-proven H. pylori infection were randomly assigned to the two following regimens: Group 1 (n = 45) received omeprazole 20 mg once daily for 2 weeks (days 1-14), and 500 mg amoxicillin granules and 250 mg metronidazole thrice daily, and roxithromycin 150 mg twice daily for 1 week (days 8-14), Group 2 (n = 45) received the same antibiotic treatment as group 1 for 1 week (days 1-7), in addition to omeprazole treatment for 2 weeks (days 1-14). Four weeks after the treatment ended, endoscopy was repeated, with two biopsy specimens each taken from the antrum and the corpus (total of four specimens) for a urease test, histological analysis, and culture to establish cure of infection. A patient was regarded as cured only if all three methods gave negative results for H. pylori. In the intention-to-treat analysis, 42 of 45 patients (93.3%; 95% confidence intervals [CI], 81.7%-98.6%) in group 1 were cured compared with 43 of 45 patients (95.6%; 95% CI, 84.9%-99.5%) in group 2. In the per-protocol analysis, the corresponding figures were 42/44 (95.5%; 95% CI 84.5%-99.4%) and 43/44 (97.7%; 95% CI, 88.0%-99.9%). There were no significant differences in the cure rate between the two groups on either analysis. All patients, except for one who had an allergic reaction, completed the treatment regimens. Fifty to sixty percent of the patients had no side effects while the rest had mild to moderate side effects. The new quadruple therapy consisting of omeprazole, amoxicillin, metronidazole, and roxithromycin appears suitable for use in clinical practice, as the cure rate was 95% and no severe side effects were observed. Pretreatment with omeprazole did not reduce the cure rate for this new quadruple therapy.

Structural insights into endoplasmic reticulum stored calcium regulation by inositol 1,4,5-trisphosphate and ryanodine receptors

The two major calcium (Ca²⁺) release channels on the sarco/endoplasmic reticulum (SR/ER) are inositol 1,4,5-trisphosphate and ryanodine receptors (IP3Rs and RyRs). They play versatile roles in essential cell signaling processes, and abnormalities of these channels are associated with a variety of diseases. Structural information on IP3Rs and RyRs determined using multiple techniques including X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy and cryo-electron microscopy (EM), has significantly advanced our understanding of the mechanisms by which these Ca²⁺ release channels function under normal and pathophysiological circumstances. In this review, structural advances on the understanding of the mechanisms of IP3R and RyR function and dysfunction are summarized. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.

Association of Helicobacter pylori infection with atrophic gastritis and intestinal metaplasia

AIMS

To evaluate the effect of Helicobacter pylori infection and aging on atrophy and intestinal metaplasia of the gastric mucosa.

METHODS

One hundred and sixty-three patients were divided into three age groups and underwent an upper gastrointestinal endoscopy where no esophagitis, peptic ulcers, or malignancies were detected. Two biopsy specimens were obtained from the anterior and posterior walls of the antrum and of the fundus. These were used to evaluate the grade of gastritis, bacterial culture and histologic evidence of H. pylori infection.

RESULTS

Helicobacter pylori infection was found to be directly associated with an increased risk of gastritis grade (odds ratio (OR) = 90 (95% CI; 30-270)). An age of 60 years and older along with H. pylori infection was also strongly associated with an increased risk of atrophy (OR = 6.6, (95% CI; 2.9-15.2)); OR = 9.8, (95% CI; 2.7-35.4)), as was intestinal metaplasia of the gastric mucosa (OR = 5.5, (95% CI; 1.7-17.6)); OR = 7.9, (95% CI; 2.8-46.1)). The prevalence of atrophic gastritis increased with advancing age in H. pylori-infected patients, but no such phenomenon was observed in H. pylori-uninfected patients. The prevalence of intestinal metaplasia significantly increased with advancing age, irrespective of the presence of H. pylori infection. In addition, H. pylori uninfected female patients had a decreased risk of intestinal metaplasia.

CONCLUSIONS

These results suggest that atrophic gastritis is not a normal aging process, but instead is likely to be the result of H. pylori infection, while intestinal metaplasia is caused by both the aging process and H. pylori infection. A decreased risk of intestinal metaplasia found in uninfected female subjects may partly explain the lower prevalence of gastric cancer in females than in males.

Structural studies of inositol 1,4,5-trisphosphate receptor: coupling ligand binding to channel gating

The three isoforms of the inositol 1,4,5-trisphosphate receptor (IP(3)R) exhibit distinct IP(3) sensitivities and cooperativities in calcium (Ca(2+)) channel function. The determinants underlying this isoform-specific channel gating mechanism have been localized to the N-terminal suppressor region of IP(3)R. We determined the 1.9 Å crystal structure of the suppressor domain from type 3 IP(3)R (IP(3)R3(SUP), amino acids 1-224) and revealed structural features contributing to isoform-specific functionality of IP(3)R by comparing it with our previously determined structure of the type 1 suppressor domain (IP(3)R1(SUP)). The molecular surface known to associate with the ligand binding domain (amino acids 224-604) showed marked differences between IP(3)R3(SUP) and IP(3)R1(SUP). Our NMR and biochemical studies showed that three spatially clustered residues (Glu-20, Tyr-167, and Ser-217 in IP(3)R1 and Glu-19, Trp-168, and Ser-218 in IP(3)R3) within the N-terminal suppressor domains of IP(3)R1(SUP) and IP(3)R3(SUP) interact directly with their respective C-terminal fragments. Together with the accompanying paper (Yamazaki, H., Chan, J., Ikura, M., Michikawa, T., and Mikoshiba, K. (2010) J. Biol. Chem. 285, 36081-36091), we demonstrate that the single aromatic residue in this region (Tyr-167 in IP(3)R1 and Trp-168 in IP(3)R3) plays a critical role in the coupling between ligand binding and channel gating.

Structural determinants for the membrane interaction of novel bioactive undecapeptides derived from gaegurin 5

Gaegurin 5 is a 24-residue, membrane-active antimicrobial peptide isolated from the skin of an Asian frog, Rana rugosa. We recently reported the antimicrobial activities of two novel undecapeptides derived from an inactive N-terminal fragment (residues 1-11) of gaegurin 5 (Won, et al. J. Biol. Chem. 2004, 279, 14784-14791). In the present work, the anticancer activities of the two antimicrobial undecapeptide analogues were additionally identified. The relationships between their structural properties and biological activities were assessed by characterizing the fundamental structural determinant for the basic membrane interaction. The circular dichroism and nuclear magnetic resonance results revealed that in a membrane-mimetic environment, the active peptides adopt a more stabilized helical conformation than that of the inactive fragment, and this conformation conferred an overall amphipathicity to the active peptides. Therefore, the most decisive factor responsible for the activity and selectivity could be the intramolecular amphipathic cooperativity, rather than the amphipathicity itself. Especially, the tryptophan residue of the active peptides seems to play a crucial role at the critical amphipathic interface that promotes and balances the amphipathic cooperativity by stabilizing both the hydrophilic and hydrophobic interactions with the membrane. Altogether, the present results suggest that the two novel undecapeptides are worthy of therapeutic development as new antibiotic and anticancer agents and provide structural information about their action mechanism.

Production of homo- and hetero-dimeric isozymes from two aldehyde oxidase genes of Arabidopsis thaliana

Polyclonal antibodies were raised against synthetic peptides or recombinant polypeptides encoded by Arabidopsis atAO-1 and atAO-2 cDNAs, which have sequences similar to maize and animal aldehyde oxidase (AO) cDNAs. Anti-atAO-1 antibodies recognized AOalpha and AObeta among the three isoforms, AOalpha, AObeta, and AOgamma, detected in Arabidopsis seedlings after native PAGE, while anti-atAO-2 antibodies reacted with AObeta and AOgamma. The polypeptide specifically recognized by each antibody was collected as the Protein-A/IgG/antigen complex. The 150- and 145-kDa polypeptides were purified by SDS-PAGE and digested with Achromobacter Protease I. From the amino acid sequences and molecular masses of the derivative peptides, it was revealed that the 150- and 145-kDa polypeptides were the products of atAO-1 and atAO-2, respectively. Molecular masses of the native forms of AOalpha, AObeta, and AOgamma were estimated as approximately 290-300 kDa. These results suggest that AOalpha and AOgamma are homodimers consisting of atAO-1 and atAO-2 products, respectively, and that AObeta is a heterodimer of the atAO-1 and atAO-2 products.

Functional expression of two Arabidopsis aldehyde oxidases in the yeast Pichia pastoris

To investigate the biochemical and enzymatic properties of two aldehyde oxidase (AO) isoforms of Arabidopsis thaliana, we expressed AAO1 and AAO2 cDNAs in a heterologous yeast (Pichia pastoris) system and successfully obtained the proteins in active forms. The expressed AAO1 and AAO2 proteins gave activity bands with the same mobilities on native gel electrophoresis and exhibited the same substrate preferences on zymograms with 8 aldehydes as those of AOalpha and AOgamma in Arabidopsis seedlings, respectively. Furthermore, anti-AAO1 and anti-AAO2 antibodies, which specifically recognize the seedling AOalpha and AOgamma, respectively, reacted with the AAO1 and AAO2 proteins produced in P. pastoris, respectively. These results indicate that these AO proteins are accurately produced in the yeast system, as in Arabidopsis seedlings. Using AO preparations from P. pastoris, the enzymatic properties of Arabidopsis AOalpha and AOgamma were investigated. AOalpha showed a relatively wide substrate specificity for 7 aldehydes tested, with high affinity to benzaldehyde and indole-3-aldehyde, while AOgamma could most efficiently oxidize naphthaldehyde. AOalpha was strongly inhibited by iodoacetate and KCN, while AOgamma was inhibited not only by iodoacetate and KCN but also by 2-mercaptethanol, dithiothreitol, menadion, and estradiol. AOalpha and AOgamma showed the highest activity at around 65 and 50 degrees C, respectively, and exhibited pH dependence around pH 8.0. These results indicate that the two AO isoforms in Arabidopsis seedlings have different enzymatic properties and may have different physiological roles in vivo.

A new endemic focus of Heterophyes nocens, Pygidiopsis summa, and other intestinal flukes in a coastal area of Muan-gun, Chollanam-do

A small coastal village of Muan-gun, Chollanam-do, was surveyed for intestinal fluke infections, especially heterophyids such as Heterophyes nocens and Pygidiopsis summa by fecal examination on 108 inhabitants. The egg positive rate of heterophyids was very high, 75.0%, and that of other parasites was comparatively low, 0.9-3.7% by parasite species. After treatment of 20 patients showing high E.P.G. with praziquantel and purging with MgSO4, total 3,864 specimens of H. nocens were collected from the diarrheic stools of all the patients treated (3-1,338 individually) and total 703 P. summa were harvested from 18 patients (1-170 individually), together with several other species of flukes. Other flukes included Stictodora fuscata (164 specimens from 4 patients), Heterophyopsis continua (2 from 2 patients), and Gymnophalloides seoi (4 from 3 patients). From this study, the surveyed coastal area of Muan-gun, Chollanam-do was proven to be a new endemic focus of H. nocens and P. summa. The occurrence of a few infected cases suggests that this area should also be a low-grade endemic area of S. fuscata, H. continua, and G. seoi.

Basic experiments with clotrimazole administered orally

A series of experiments was carried out with the antimycotic agent clotrimazole to establish MICs against a number of different yeasts and to estimate its blood levels following oral administration. Marked differences were noted between the MIC against A and B serotypes of Candida albicans in its yeast-like cell form, that against Type B being nearly 10-times higher than against Type A. Against the mycelial form, however, the MIC was much lower and there was little difference between the levels for the two serotypes. Clotrimazole administered in oral tablet form appeared to be poorly absorbed, little being transferred to the blood. Urinary levels were low and large amounts of the drug were detected in the faeces. Serum levels were below MIC levels in all cases examined. Blood levels 3-times as great as those after the same dosage in tablet form were produced when clotrimazole was given in oil solution and even with 250 mg, effective blood levels were achieved and maintained.

Correlation between endoscopic severity and the clinical activity index in ulcerative colitis

OBJECTIVE

The aim of this study was to examine the relationship between a new activity index and the endoscopic severity assessed by sigmoidoscopy in patients with ulcerative colitis.

METHODS

We evaluated the sigmoidoscopic severity and Activity Index (AI) in 37 patients with distal colitis, 23 with left-sided colitis, and 36 with total colitis, in which the severity was divided into three categories: grade 1 = mildly active, grade 2 = moderately active, and grade 3 = severely active. We examined the relationship between the AI or clinical parameters and the endoscopic severity in all 96 cases.

RESULTS

The AI was found to be significantly correlated with the degree of sigmoidoscopic activity in all cases, as well as in those with distal colitis, left-sided colitis, or total colitis. When patients with both grade 1 sigmoidoscopic activity and AI values of less than 150 were regarded to have mild colitis and patients with either grade 2 or grade 3 sigmoidoscopic activity and AI values of more than 150 were regarded to have moderate or severe colitis, 10 of 37 (27%) in the distal colitis, one of 23 (4.3%) in the left-sided colitis, and four of 36 (11.1%) in the total colitis groups were thus misclassified regarding the distinction between mild colitis and moderate or severe colitis. Three of four patients with severity of grade 1, indicating AI values of more than 150, had total colitis, whereas the remaining one had left-sided colitis. On the other hand, 10 of 11 patients with severity of grades 2 or 3 with AI values of less than 150 had distal colonic involvement. When the endoscopic activity was equivalent, the highest mean AI values occurred in total colitis whereas the lowest mean AI values were found in distal colitis.

CONCLUSIONS

The AI well reflects the sigmoidoscopic activity. High AI values with a low sigmoidoscopic severity are thus considered to reflect extensive involvement, whereas a high sigmoidoscopic severity with low AI values is thought to indicate the involvement of the distal colon.

Control of clonorchiasis by repeated praziquantel treatment and low diagnostic efficacy of sonography

In Korea, Clonorchis sinensis infection is still highly prevalent because case detection in the field is difficult and the detected cases used to be incompletely cured due to treatment failure. The present study tried to control clonorchiasis in an endemic village by repeated treatments with praziquantel every 6 months and to evaluate sonography as a diagnostic measure. By stool examinations, the egg positive rate in the endemic village was 22.7%, but it decreased to 19.6% at 6 months, 15.1% at 12 months. 12.2% at 18 months, 6.3% at 24 months, 11.4% at 30 months, and 6.3% at 42 months after the beginning of repeated praziquantel administration. The sonography showed 61 (49.6%) positive cases of 123 screened residents: among egg-positives the sonography positive rate was 52.2% and among egg-negatives it was still 49%. The rate among cured cases was 64.3% after 6 months, 50.0% after 12 months, 50.0% after 18 months, and 66.7% after 24 months. In a non-endemic village, 64 residents were found egg-negative by fecal examination, but 20 (31.3%) of them were positive by sonography. The present findings indicate that control of clonorchiasis in an endemic village by repeated praziquantel treatment for 42 months is still insufficient and sonography is of little value for diagnosis of clonorchiasis.