Antifungal activity of streptavidin C1 and C2 against pathogens causing Fusarium wilt

Fusarium wilt is caused by the soil-inhabiting fungus Fusarium oxysporum ff. spp. and is one of the most devastating plant diseases, resulting in losses and decreasing the quality and safety of agricultural crops. We recently reported the structures and biochemical properties of two biotin-binding proteins, streptavidin C1 and C2 (isolated from Streptomyces cinnamonensis strain KPP02129). In the present study, the potential of the biotin-binding proteins as antifungal agent for Fusarium wilt pathogens was investigated using recombinant streptavidin C1 and C2. The minimum inhibitory concentration of streptavidin C2 was found to be 16 µg ml^-1 for inhibiting the mycelial growth of F. oxysporum f.sp. cucumerinum and F. oxysporum f.sp. lycopersici, while that of streptavidin C1 was found to be 64 µg ml^-1 . Compared with the nontreated control soil, the population density of F. oxysporum f.sp. lycopersici in the soil was reduced to 49·5% and 39·6% on treatment with streptavidin C1 (500 µg ml^-1 ) and C2 (500 µg ml^-1 ), respectively. A greenhouse experiment revealed that Fusarium wilt of tomato plants was completely inhibited on soil drenching using a 50-ml culture filtrate of the streptavidin-producing strain KPP02129.

Liquid crystal filter based tunable transmitter for 25Gps wavelength division multiplexing-passive optical network fronthaul

A novel tunable transmitter structure based on liquid crystal filter, to the best of our knowledge, is presented. The structure is designed for application to 5G fronthaul and supports 25 Gbps dense wavelength division multiplexing (WDM) transmission and tunable range of 35 nm. The design takes into account easy change of operation band over coarse WDM grid. Prototype samples are developed to test feasibility of the design.

Electric field-induced changes in biomechanical properties in human dermal fibroblasts and a human skin equivalent

PURPOSE

An electric field (EF) can be used to change the mechanical properties of cells and skin tissues. We demonstrate EF-induced elasticity changes in human dermal fibroblasts (HDFs) and a human skin equivalent and identify the underlying principles related to the changes.

METHODS

HDFs and human skin equivalent were stimulated with electric fields of 1.0 V/cm. Change in cellular elasticity was determined by using atomic force microscopy. Effects of EF on the biomechanical and chemical properties of a human skin equivalent were analyzed. In cells and tissues, the effects of EF on biomarkers of cellular elasticity were investigated at the gene and protein levels.

RESULTS

In HDFs, the cellular elasticity was increased and the expression of biomarkers of cellular elasticity was regulated by the EF. Expression of the collagen protein in the human skin equivalent was changed by EF stimulation; however, changes in density and microstructure of the collagen fibrils were not significant. The viscoelasticity of the human skin equivalent increased in response to EF stimulation, but molecular changes were not observed in collagen.

CONCLUSIONS

Elasticity of cells and human skin equivalent can be regulated by electrical stimulation. Especially, the change in cellular elasticity was dependent on cell age.

Effects of red ginseng on the elastic properties of human skin

Background

Red ginseng contains components, including microelements, vitamins, essential oils, and fatty acids, that can be used in skincare to delay the aging process. We investigated the effects of red ginseng treatment on skin elasticity by assessing cellular stiffness and measuring collagen protein synthesis.

Methods

Human dermal fibroblasts were treated with red ginseng, and the resulting changes in stiffness were investigated using atomic force microscopy. Cytoskeletal changes and mRNA expression of biomarkers of aging, including that of procollagens I and VII, elastin, and fibrillin-1, were investigated. Collagen in a human skin equivalent treated with red ginseng was visualized via hematoxylin and eosin staining, scanning electron microscopy, and atomic force microscopy.

Results and conclusion

The stiffness of fibroblasts was significantly reduced by treatment with red ginseng concentrations of ≥ 0.8 mg/mL. The ratio of F-actin to G-actin decreased after treatment, which corresponded to a change in fibroblast stiffness. The storage modulus (G′) and loss modulus (G″) of the skin equivalent were both lowered by red ginseng treatment. This result indicates that the viscoelasticity of the skin equivalent can be restored by red ginseng treatment.

Assessment of pressure pain thresholds in collisions with collaborative robots

In recent years, safety issues surrounding robots have increased in importance, as more robots are in close contact with humans, both in industrial fields and elsewhere. Safety standards for industrial robots operating in specific spaces have been established, but no such standards have been specified for collaborative and service robots. To establish safety standards for such robots, we assessed pressure pain thresholds for collisions between humans and robots, under the assumption that the pain threshold is lower than the mild injury threshold. The pressure pain threshold for collision with a robot was measured in 90 male Korean adults using a homemade collision system. The pain thresholds were measured three times at 15 sites, including the forehead. The highest threshold was 196.1 ± 85.8 N/cm² at the back of the hand, and the lowest was 65.1 ± 22.6 N/cm² at an arm nerve. Moderate thresholds, i.e., 100–120 N/cm², were noted on the forehead, neck muscle, ball of the thumb, and shin. The thresholds of participants < 30 years of age were lower, by 3–33%, than those of participants aged > 30 years. Thresholds differed by body mass index only at certain sites, including the shoulder joint, neck, and back of the hand. The pressure pain threshold depended on individual characteristics, body site, and age. The threshold relevant to potential human-robot collisions was determined to be between 65.1 ± 22.6 and 196.1 ± 85.8 N/cm².

Identification of a closed cutaneous injury after mechanical trauma caused by collision

PURPOSE

Robotics has evolved rapidly in terms of mechanical design and control in the past few years. Collaborative robots that have direct contact with humans are being introduced in various fields, including industrial and medical services. Because collaborative robot systems are being introduced rapidly, the safety of the humans who work with them is becoming an important issue. In this study, we investigated skin injuries resulting from a collision between robots and humans using a freefall experiment system.

METHODS

We particularly focused on closed skin injuries caused by a collision. To induce a closed injury, we struck mini-pigs with cubic-edge square and semi-sphere impactors at collision speeds of 1 and 3 m/s. We did not observe any open injuries with those conditions. Closed injuries were observed in the dermal layer of the skin after the collision test at both speeds and with both impactors.

RESULTS

The collagen fiber in the dermal layer was separated and fragmented, and the subcutaneous fat layer became dense as a result of the collision.

CONCLUSIONS

We closely observed and analyzed the histopathologic changes in the dermal and subcutaneous layers with intact epidermis after mechanical trauma to the inner skin layers.

Analysis of the number of enlarged pores according to site, age, and sex

BACKGROUND

Increasing the number of enlarged pores causes cosmetic problems. The difference in the number of enlarged pores according to facial site, age, and sex is unclear.

OBJECTIVE

To analyze the distribution of the number of enlarged pores according to facial site, age, and sex.

METHODS AND MATERIALS

We analyzed the number of the enlarged pores and the percentage of wrinkles in the nose, forehead, and cheek from 434 polarized images. The measurement results were analyzed according to site, age, and sex. Relationship between enlarged pore counts and wrinkle severity was also analyzed. The study was conducted by using DermaVision,™ which can take cross-polarization, parallel polarization, and ultraviolet light images.

RESULTS

The enlarged pores of the nose and forehead were more prominent than in the cheeks. Pore counts were increased with age, and the increment was significant between the 30's and 40's. There was no significant difference by gender. Enlarged pore counts were related to wrinkle severity.

CONCLUSIONS

The number of enlarged pores differs depending on body site and increased with age. The enlarged pore counts correlate with wrinkle severity and the correlation varies depending on the body site.

Airway management using a supraglottic airway device without endotracheal intubation for positive ventilation of anaesthetized rats

Endotracheal intubation is often necessary for positive pressure ventilation of rats during open thoracic surgery. Since endotracheal intubation in rats is technically difficult and is associated with numerous complications, many techniques using various devices have been described in the scientific literature. In this study, we compared the effectiveness of airway management of a home-made supraglottic airway device (SAD), which is cheap to fabricate and easy to place with that of an endotracheal intubation tube in enflurane-anaesthetized rats. Twenty male Sprague-Dawley rats (200-300 g) were randomly assigned to two equal groups for positive pressure mechanical ventilation using either the SAD or an endotracheal intubation tube. The carotid artery of each rat was cannulated for continuous blood pressure measurements and obtaining blood samples for determination of oxygen tension, carbon dioxide tension, and blood acidity before, during and after SAD placement or endotracheal intubation. Proper placement of the SAD was confirmed by observing chest wall movements that coincided with the operation of the mechanical ventilator. No complications and adverse events were encountered in the rats in which the SAD was placed, during SAD placement and immediate removal, during their mechanical ventilation through the SAD, and one week after SAD removal. From the results of blood gas analyses, we conclude that anaesthetized rats can be successfully ventilated using an SAD for open thoracic surgery.

Construction of an open-access QT database for detecting the proarrhythmia potential of marketed drugs: ECG-ViEW

Information about the QT interval from surface electrocardiograms (ECGs) is essential for surveillance of the proarrhythmia potential of marketed drugs. However, ECG records obtained in daily practice cannot be easily used for this purpose without labor-intensive manual effort. This study was aimed at constructing an open-access QT database, the Electrocardiogram Vigilance with Electronic Data Warehouse (ECG-ViEW). This longitudinal observational database contains 710,369 measurements of QT and associated clinical data from 371,401 patients. The de-identified database is freely available at http://www.ecgview.org.

The first detection of Brucella canis in cattle in the Republic of Korea

Twenty mammary lymph node samples were collected from cattle on a farm in the Republic of Korea. These cattle were serologically negative for Brucella by tube agglutination test (≤ 1:50) and serum agglutination test (≤ 1:50). Out of 20 lymph node samples, two samples were positive for Brucella growth on Brucella agar as well as blood agar. Tests for urease, hydrogen sulphide and reactions against monospecific sera A and M indicated that these two isolates (No. 15 and 16) belong to the genus Brucella. Genus specific, AMOS (abortus, melitensis, ovis, suis) and Bruce-ladder multiplex polymerase chain reaction (PCR) assays confirmed the Brucella isolates as either a B. abortus or a B. canis strain. This is the first report of the occurrence of a B. canis infection in cattle in Korea. More survey data are needed to determine whether B. canis is a significant aetiology in the cases of cattle brucellosis in Korea.

Fraudulent retouching of digital radiographic images--a potential risk

AIM

To determine whether radiologists can recognize images retouched to include sham lesions.

MATERIALS AND METHODS

Ten representative key images were selected of aortic dissection, hepatocellular carcinoma, renal cell carcinoma, colon cancer, liver metastasis, hepatic cyst, gallbladder stones, splenic artery aneurysm, adrenal adenoma, and stomach cancer from abdominal computed tomography (CT) imaging performed in 2008. Five of the key images were replaced with retouched images using image-editing software. The time to complete retouching was recorded for each image. Radiologists were requested to make a diagnosis for the 10 images, and were then asked to identify possible retouched images. The time taken to reach a decision in each case was recorded. Thirty radiologists (13 residents and 17 attending radiologists) participated as reviewers.

RESULTS

The time to complete retouching was 15.2±3.15 min. None of the reviewers recognized that some images were retouched during diagnosis. The rate of correct diagnosis was 90% (range 71.7-100%). After reviewers were informed of possible image retouching, the detection rate of retouched images was 50% (40-58.3%). This rate was statistically the same as random choice (p=0.876). There was no significant difference between residents and attending radiologists in the detection rate of retouched images (p=0.786). The time to diagnosis and the time to detection of the retouched images were 15 (14-17) and 6 (5-7) min, respectively.

CONCLUSION

Digital images can be easily retouched, and radiologists have difficulty in identifying retouched images. Radiologists should be aware of the potential fraudulent use of retouched images.

Inhibition of Orientia tsutsugamushi infection by a truncated recombinant 56-kDa outer membrane protein

AIMS

The objective of this study was to evaluate recombinant 56-kDa outer membrane protein as a potential inhibitor to infection from Orientia tsutsugamushi.

METHODS AND RESULTS

The 56-kDa protein was cloned and expressed in an Escherichia coli system, and the degree of target cell attachment to immobilized 56-kDa protein was measured in a cell adhesion assay. The results showed that the 56-kDa protein has an ability to attach HeLa cells. Furthermore, treatment of target cells with a truncated 56-kDa 1-418 (amino acid residues) protein inhibited target cell infection by O. tsutsugamushi, demonstrated with an indirect immunofluorescence antibody assay.

CONCLUSIONS

The truncated 56-kDa protein (a.a. 1-418) plays an important role in O. tsutsugamushi infection, and the 56-kDa protein could be useful and effective in the inhibition of O. tsutsugamushi attachment and infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

The attachment of the 56-kDa protein to target cells was directly determined by in vitro adherence test, and the invasion of target cells by O. tsutsugamushi was inhibited by treating the target cells with a truncated 56-kDa protein.

Adoptive immunotherapy using human peripheral blood lymphocytes transferred with RNA encoding Her-2/neu-specific chimeric immune receptor in ovarian cancer xenograft model

The current gene transfer technology for single chain (scFv)-based chimeric immune receptor (CIR) has relied on retrovirus and lentivirus vectors which require a long time to obtain sufficient number of transduced cells and stably incorporate into genome. To ameliorate these limitations, we applied RNA electroporation to human peripheral blood lymphocytes (PBLs) activated with anti-CD3 antibody and interleukin-2 (IL-2) for 3 days and assessed that PBL transiently expressing anti-Her-2/neu CIR (CIR-PBL) containing signaling portion of CD28 and CD3zeta could elicit strong cytotoxicity in vitro and antitumor responses in vivo. The CIR-PBL expressed high level of CIR in CD4+, CD8+ and CD56+ cells. Her-2/neu-specific stimulation induced secretion of type-I cytokines including interferon-gamma (IFN-gamma), IL-8 and granulocyte-macrophage colony-stimulating factor, and IFN-gamma secretion was mainly mediated by CD8+ T cells. CIR-PBL specifically killed SKOV3 cell line expressing Her-2/neu. Adoptive transfer of CIR-PBL in SKOV3 xenograft model led to significant inhibition of tumor growth compared with transfer of mock-transduced PBL and showed higher inhibition than those with Herceptin, humanized monoclonal antibody specific for Her-2/neu. These results provided evidence that electroporation of CIR RNA to human PBLs could be used for rapid generation and high number of therapeutic antigen-specific T cells for adoptive immunotherapy.

Coexistence of ductal constriction and closure of the foramen ovale in utero

We report a fetus with an unusual combination of a narrow ductus arteriosus (DA) and foramen ovale. A pregnant mother was referred at 26 weeks of gestation for fetal pericardial effusion. Fetal echocardiography showed pericardial effusion, right atrial enlargement, right ventricular hypertrophy, and tricuspid regurgitation. The DA looked tortuous with S-shaped kinking. The atrial septum primum bulged into the left atrium. Color Doppler did not show any flow across the atrial septum. Cesarean section was performed at 31 weeks of gestation. Admission to intensive care was required after delivery, but the infant gradually improved and was discharged home without any sequela.

Cisplatin-induced apoptosis by translocation of endogenous Bax in mouse collecting duct cells

cis-platinum(II) (cis-diammine dichloroplatinum; cisplatin) is a potent antitumor compound that is widely used for the treatment of many malignancies. An important side-effect of cisplatin is nephrotoxicity, which results from injury to renal tubular epithelial cells and can be manifested as either acute renal failure or a chronic syndrome characterized by renal electrolyte wasting. Recently, apoptosis has been recognized as an important mechanism of cell death mediating the antitumor effect of cisplatin. This study was undertaken to examine the mechanisms of cell death induced by cisplatin in M-1 cells, which were derived from the outer cortical collecting duct cells of SV40 transgenic mice. Treatment of M-1 cells with high concentrations of cisplatin (0.5 and 1 mM) for 2 hr led to necrotic cell death, whereas a 24-hr treatment with 5-20 microM cisplatin led to apoptosis. Antioxidants protected against cisplatin-induced necrosis, but not apoptosis, indicating that reactive oxygen species play a role in mediating necrosis but not apoptosis induced by cisplatin and that the mechanism of cell death induced by cisplatin is concentration dependent. The low concentrations of cisplatin, which induced apoptosis in M-1 cells, did not affect the expression levels of Bcl-2-related proteins and did not activate c-Jun NH2-terminal kinase (SAPK/JNK). Cisplatin induced the translocation of endogenous Bax from the cytosolic to the membrane fractions and, subsequently, the release of cytochrome c. Overexpression of Bcl-2 blocked cisplatin-induced apoptosis and Bax translocation. These observations suggest that the subcellular redistribution of Bax is a critical event in the apoptosis induced by cisplatin.

The behavior of a poly(aniline) solid contact pH selective electrode based on N,N,N',N'-tetrabenzylethanediamine ionophore

A hydrogen ion-selective solid-contact electrode based on N,N,N',N'-tetrabenzylethanediamine has shown the best Nernstian slope and selectivity and the widest response range in a Tris buffered pH sample solution. Its linear dynamic range was pH 3.50-11.94, and the Nernstian slope showed 52.1 mV/pH (at 20 +/- 0.2 degrees C). When it was directly applied to human whole blood (in pH range 6.0-8.5) we could obtain the same satisfying results. This electrode continuously contacted a Tris 7.47 buffered solution, human whole blood and a hydrofluoric acid solution for one month without any loss of performance. Also, hydrofluoric acid did not influence the surface of this electrode, and thus it was maintained without showing any changes in potentials after being used in a hydrofluoric acid solution. The standard deviation in the determined e.m.f. differences was 1.5 mV (N = 5) for Tris buffer solutions of pH 6.5 and 1.1 mV at a Tris buffer solutions of pH 8.5. The 90% response time of the electrodes obtained by injecting of hydrochloric acid into the Tris buffer sample solution was less than 10 s. Especially, in the this paper, with these potential response characteristics of hydrogen ion selective poly(aniline) solid contact electrode, we have also presented the pH response mechanism of this electrode and the role of poly(aniline) and a doped anion in a poly(aniline) layer.

Hormonal cross-talk between auxin and ethylene differentially regulates the expression of two members of the 1-aminocyclopropane-1-carboxylate oxidase gene family in rice (Oryza sativa L.)

Two cDNA clones, pOS-ACO2 and pOS-ACO3, encoding 1-aminocyclopropane-1-carboxylate (ACC) oxidase were isolated from rice seedling cDNA library. pOS-ACO3 is a 1,299 bp full-length clone encoding 321 amino acids (Mr=35.9 kDa), while pOS-ACO2 is 1,072 bp long and is a partial cDNA clone encoding 314 amino acids. These two deduced amino acid sequences share 70% identity, and display a high degree of sequence identity (72-92%) with previously isolated pOS-ACO1 of deepwater rice. The chromosomal location studies show that OS-ACO2 is positioned on the long arm of chromosome 9, while OS-ACO3 on the long arm of chromosome 2 of rice genome. A marked increase in the level of OS-ACO2 transcript was observed in IAA-treated etiolated rice seedlings, whereas the OS-ACO3 mRNA was greatly accumulated by ethylene treatment. Results of ethylene inhibitor studies indicated that auxin promotion of the OS-ACO2 transcription was not mediated through the action of auxin-induced ethylene. Thus, it appears that there are two groups of ACC oxidase transcripts in rice plants, either auxin-induced or ethylene-induced. The auxin-induced OS-ACO2 expression was partially inhibited by ethylene, while ethylene induction of OS-ACO3 transcription was completely blocked by auxin. These results indicate that the expression of ACC oxidase genes is regulated by complex hormonal networks in a gene specific manner in rice seedlings. Okadaic acid, a potent inhibitor of protein phosphatase, effectively suppressed the IAA induction of OS-ACO2 expression, suggesting that protein dephosphorylation plays a role in the induction of ACC oxidase by auxin. A scheme of the multiple regulatory pathways for the expression of ACC oxidase gene family by auxin, ethylene and protein phosphatase is presented.

Botulinum toxin A for the treatment of facial hyperkinetic wrinkle lines in Koreans

There are a number of different causes for facial wrinkle lines, such as aging, gravity, and chronic pulling of mimetic muscles on the face. Among these, pulling by mimetic muscles on the skin not only involves facial expression but also has a great role in forming facial wrinkle lines as a result of repetitive action, such as dynamic or hyperkinetic wrinkle lines. Botulinum toxin A is currently being used for eliminating facial hyperkinetic wrinkles by causing paralysis of the underlying mimetic muscles. Because there are some histologic differences between Asians and Caucasians, such as thick dermis and more abundant collagen fiber, etc., the chronic pulling by mimetic muscles on the skin is expected to affect facial wrinkles differently. Therefore, the purpose of this study was to determine the efficacy of botulinum toxin A injection in eliminating facial hyperkinetic wrinkle lines among Korean patients. This study included 38 patients and 59 injection sessions from January of 1996 to April of 1997. We used Botox containing 100 U. Toxin was diluted with 4 ml of sterile normal saline and yielded 2.5 U for each 0.1 cc. A dose of 5 to 10 U was used in each muscle. Ages ranged from 26 to 56 years. There were 33 women and 5 men included in this study. Thirty-two of the patients were followed from 3 months up to 12 months after injections. The number of injection sessions that were performed on each patient was as follows: one session, 23 patients; two sessions, 10 patients; three sessions, 4 patients; four sessions, 1 patient. The number of injections per target site among these 38 patients was as follows: lateral canthal area, 33; glabellar area, 9; forehead, 9; nasal dorsum, 5. The most common duration of effective response was about 4 months, but in eight patients the period was over 5 months. After the response, complete recovery took about 1 or 2 months. Two patients felt unsatisfied, 5 patients felt slightly improved, and 25 patients retained only a slight line and were satisfied with the results. None of the patients experienced complete removal of wrinkle lines. Adverse effects included altered facial looks or appearances, mild local swelling, and ecchymosis at the injection sites. No systemic side effects were noted. Based on these results, the injection of botulinum toxin A seems to be an effective method of eliminating wrinkle lines on the upper third of the face in Korean patients, and it was a simple and effective nonsurgical procedure.

Apoptosis induced by inhibition of contact with extracellular matrix in mouse collecting duct cells

Cell-matrix interactions have major effects upon phenotypic features such as gene regulation, cytoskeletal structure, differentiation and aspects of cell growth control. Detachment from the matrix epithelial cells induces programmed cell death, and this cell detachment induced apoptosis has been referred to as 'anoikis'. This study was undertaken to determine whether apoptosis is induced by inhibition of contact with extracellular matrix (ECM) in collecting duct cells and to investigate the signaling mechanisms of the process. Upon detachment from ECM, mouse inner medullary collecting duct cells (mIMCD-3) and mouse outer cortical collecting duct cells (M-1), which were derived from an SV40 transgenic mouse, entered into programmed cell death. Forced suspension of mIMCD-3 or M-1 cells did not affect the expression of Bcl-2-related proteins and did not activate c-Jun NH(2)-terminal kinase. Detachment of cells from ECM activated p38 mitogen-activated protein kinase (p38), but its inhibition with SB203580 did not protect cells from anoikis. Detachment of cells from matrix inhibited NF-kappaB activity, and the inhibition of NF-kappaB activity by overexpression of nonphosphorylatable I-kappaB increased detachment-induced apoptotic cell death in M-1 cells. Forced suspension of M-1 cells still activated p53 activity. Caspase-8 was activated during anoikis, but the time course of its activation was in accordance with DNA fragmentation. These results indicate that detachment from ECM induces apoptosis in the kidney collecting duct cells. Changes in expression levels of Bcl-2-related proteins or activation of JNK/p38 kinase are not critical for anoikis. Decrease in NF-kappaB activity and activation of p53 induced by inhibition of interaction with ECM play roles in anoikis in SV-40-transformed collecting duct cells. Caspase-8 is activated during detachment-induced apoptosis, the mechanisms of which are independent of activation of cell death receptors.

Protection against hydrogen peroxide induced injury in renal proximal tubule cell lines by inhibition of poly(ADP-ribose) synthase

Radicals including superoxide anions, hydrogen peroxide or hydroxyl radicals and NO or peroxynitrite cause the breakage of DNA strands and activation of poly-(ADP-ribose) synthase (PARS). Recent studies showed that inhibition of PARS activity reduces the tissue injury after exposure to oxidative stress. However, the role of PARS in renal injury by oxidants has not been examined. In this study effect of a PARS inhibitor, 3-aminobenamide (3-AB), on injury of opossum kidney or LLC-PK(1) cells by hydrogen peroxide or tert-butyl hydroperoxide (t-BHP) was examined. The exposure of opossum kidney cells to hydrogen peroxide activated PARS and decreased cellular adenosine triphosphate levels in a concentration-dependent manner. Inhibition of PARS with 3-AB prevented the cell death induced by hydrogen peroxide and also prevented adenosine triphosphate depletion. 3-AB did not have hydroxyl radical scavenging effect. In contrast, t-BHP did not affect the PARS activity. The decrease in cellular adenosine triphosphate levels by t-BHP was less than that by hydrogen peroxide. 3-AB failed to prevent the cell death induced by t-BHP. PARS activation after exposure of hydrogen peroxide was inhibited by addition of t-BHP. However, t-BHP showed an additive effect on cell death with hydrogen peroxide. These results indicate that activation of PARS plays an important role in hydrogen peroxide induced injury in opossum kidney cells and that hydrogen peroxide and t-BHP induce cell injury by different mechanisms.

Inhibitory effects of chlorophyllin on 7,12-dimethylbenz[a]anthracene-induced bacterial mutagenesis and mouse skin carcinogenesis

Chlorophyllin (CHL), a water-soluble derivative of chlorophyll, has been used for the treatment of several abnormal human conditions without apparent toxicity. Recent studies have revealed that CHL has the excellent chemopreventive potential. In the present investigation, we have found the inhibitory activities of CHL against 7,12-dimethylbenz[a]anthracene (DMBA)-induced mutagenesis in Salmonella typhimurium TA100 and also on DMBA-initiated and 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-promoted mouse skin tumor formation. The incidence and the multiplicity of skin tumors were not significantly decreased in mice by a single topical application of CHL prior to the DMBA treatment, but there was a marked suppression of papillomagenesis in mice treated with CHL during the promotional stage. Furthermore, the formation of DMBA-induced papillomagenesis was reduced in all mice that had received CHL for 6 weeks following treatment with TPA for 6, 18 and 24 weeks. These results indicate that CHL can inhibit both tumor promotion and the progression of papillomagenesis in the two-stage mouse skin carcinogenesis induced by DMBA and TPA.

Rescue of cyclin D1 deficiency by knockin cyclin E

D-type cyclins and cyclin E represent two very distinct classes of mammalian G1 cyclins. We have generated a mouse strain in which the coding sequences of the cyclin D1 gene (Ccnd1) have been deleted and replaced by those of human cyclin E (CCNE). In the tissues and cells of these mice, the expression pattern of human cyclin E faithfully reproduces that normally associated with mouse cyclin D1. The replacement of cyclin D1 with cyclin E rescues all phenotypic manifestations of cyclin D1 deficiency and restores normal development in cyclin D1-dependent tissues. Thus, cyclin E can functionally replace cyclin D1. Our analyses suggest that cyclin E is the major downstream target of cyclin D1.

Expression of excitation-contraction coupling proteins during muscle differentiation

The goal of this study was to characterize three major excitation-contraction (E-C) coupling proteins: ryanodine receptor [RyR, the calcium release channel in the sarcoplasmic reticulum (SR)], dihydropyridine receptor (DHPR, the voltage-gated L-type calcium channel in the transverse tubule) and SR Ca2+-ATPase (SERCA, the calcium pump in the SR) in the differentiating primary cultures of rat skeletal and cardiac muscle cells. The expression levels of these proteins were determined by ligand binding assays and/ or immunoblottings along with an examination of the morphological changes in differentiating muscles by phase-contrast microscopy. In the skeletal cells, the expression levels of the E-C coupling proteins generally increased in the course of differentiation with the peak expression at the 9th day of culture. Simultaneous with the increased expression of the proteins, the myoblasts elongated, followed by alignment and fusion of the cells to form multinucleated myotubes. In the cardiac cells, on the contrary, the peak expression levels of DHPR, SERCA and RyR were reached within 2, 4, and 7 d of culture, respectively. Alignment of the cardiac muscle cells and spontaneous contraction occurred as early as several h after plating. These results suggest that expression patterns of E-C coupling proteins are different between skeletal and cardiac muscles, and that DHPR could play an important role in Ca2+ metabolism during the early stages of differentiation.

Synthetic peptides corresponding to various hydrophilic regions of the large subunit of cytochrome b558 inhibit superoxide generation in a cell-free system from neutrophils

Cytochrome b558 is a component of the superoxide-generating system in neutrophils and plays key roles in both the assembly of a functional complex with cytosolic proteins and shuttling an electron from NADPH to molecular oxygen. To determine the role of predicted hydrophilic domains of gp91-phox, a glycosylated subunit of the cytochrome, we synthesized peptides corresponding to the regions and tested whether they affected superoxide generation in the cell-free system obtained from human neutrophils. Among twelve peptides tested, six peptides, four of which correspond to previously unreported regions, inhibited superoxide generation in the cell-free system. All of the active peptides were effective when added to the system before activation with sodium dodecyl sulfate. Four peptides, including two peptides corresponding to two newly identified regions, inhibited the translocation of the cytosolic components, p47-phox and p67-phox. The extent of inhibition on translocation of these components varied depending on the peptide used.

Cyclin D2 is an FSH-responsive gene involved in gonadal cell proliferation and oncogenesis

THE D-type cyclins (D1, D2 and D3) are critical governors of the cell-cycle clock apparatus during the G1 phase of the mammalian cell cycle. These three D-type cyclins are expressed in overlapping, apparently redundant fashion in the proliferating tissues. To investigate why mammalian cells need three distinct D-type cyclins, we have generated mice bearing a disrupted cyclin D2 gene by using gene targeting in embryonic stem cells. Cyclin D2-deficient females are sterile owing to the inability of ovarian granulosa cells to proliferate normally in response to follicle-stimulating hormone (FSH), whereas mutant males display hypoplastic testes. In ovarian granulosa cells, cyclin D2 is specifically induced by FSH via a cyclic-AMP-dependent pathway, indicating that expression of the various D-type cyclins is under control of distinct intracellular signalling pathways. The hypoplasia seen in cyclin D2(-/-) ovaries and testes prompted us to examine human cancers deriving from corresponding tissues. We find that some human ovarian and testicular tumours contain high levels of cyclin D2 messenger RNA.

Beta subunit Glu-185 of Escherichia coli H(+)-ATPase (ATP synthase) is an essential residue for cooperative catalysis

Glu-beta 185 of the Escherichia coli H(+)-ATPase (ATP synthase) beta subunit was replaced by 19 different amino acid residues. The rates of multisite (steady state) catalysis of all the mutant membrane ATPases except Asp- beta 185 were less than 0.2% of the wild type one; the Asp- beta 185 enzyme exhibited 15% (purified) and 16% (membrane-bound) ATPase activity. The purified inactive Cys- beta 185 F1-ATPase recovered substantial activity after treatment with iodoacetate in the presence of MgCl2; maximal activity was obtained upon the introduction of about 3 mol of carboxymethyl residues/mol of F1. The divalent cation dependences of the S-carboxymethyl- beta 185 and Asp- beta 185 ATPase activities were altered from that of the wild type. The Asp- beta 185, Cys- beta 185, S-carboxymethyl-beta 185, and Gln- beta 185 enzymes showed about 130, 60, 20, and 50% of the wild type unisite catalysis rates, respectively. The S-carboxymethyl- beta 185 and Asp- beta 185 enzymes showed altered divalent cation sensitivities, and the S-carboxymethyl- beta 185 enzyme showed no Mg2+ inhibition. Unlike the wild type, the two mutant enzymes showed low sensitivities to azide, which stabilizes the enzyme Mg-ADP complex. These results suggest that Glu- beta 185 may form a Mg2+ binding site, and its carboxyl moiety is essential for catalytic cooperativity. Consistent with this model, the bovine glutamate residue corresponding to Glu- beta 185 is located close to the catalytic site in the higher order structure (Abrahams, J.P., Leslie, A.G.W., Lutter, R ., and Walker, J.E. (1994) Nature 370, 621-628)

Clinicopathologic significance of the K-ras gene codon 12 point mutation in stomach cancer. An analysis of 140 cases

BACKGROUND

The frequency and clinicopathologic significance of the K-ras gene point mutation in stomach cancer remain to be defined.

METHODS

The authors investigated the frequency of K-ras codon 12 point mutations in stomach cancer using a sensitive polymerase chain reaction (PCR)-based method in 140 samples and correlated the findings with various clinicopathologic characteristics of the patients.

RESULTS

The overall frequency of K-ras codon 12 point mutations in stomach cancer was 7.9% (11/140). DNA sequencing of nine cases with K-ras codon 12 point mutations identified seven cases with a single-base substitution of GGT to AGT (glycine to serine) and two with single-base substitution of GGT to AGT (aspartic acid). Tumors located in the upper third of the stomach had a significantly higher frequency of K-ras codon 12 mutations (3/8, 37.5%) compared with tumors located in the middle (4/29, 13.8%) or lower (3/99, 3.0%) thirds of the stomach (P = 0.001). No significant difference was observed in the frequency of K-ras codon 12 mutations in terms of other various clinicopathologic characteristics including tumor DNA ploidy and S-phase fraction. After a median follow-up of 26 months, disease free and overall survival were not significantly different between patients with stomach cancer with or without K-ras codon 12 mutation. Among eight patients with stomach cancer located in the upper part of the stomach, none of the three patients with K-ras gene-mutated tumors died versus four of five with tumors without K-ras gene mutations (P = 0.064).

CONCLUSIONS

K-ras codon 12 point mutations are uncommon in stomach cancer (7.9%). There was significant correlation between K-ras mutations and vertical tumor location in the stomach, suggesting that different mechanisms may play a role in the pathogenesis of stomach cancer according to the location of tumors in the stomach.

Clinicopathologic significance of the K-ras gene codon 12 point mutation in stomach cancer. An analysis of 140 cases

BACKGROUND

The frequency and clinicopathologic significance of the K-ras gene point mutation in stomach cancer remain to be defined.

METHODS

The authors investigated the frequency of K-ras codon 12 point mutations in stomach cancer using a sensitive polymerase chain reaction (PCR)-based method in 140 samples and correlated the findings with various clinicopathologic characteristics of the patients.

RESULTS

The overall frequency of K-ras codon 12 point mutations in stomach cancer was 7.9% (11/140). DNA sequencing of nine cases with K-ras codon 12 point mutations identified seven cases with a single-base substitution of GGT to AGT (glycine to serine) and two with single-base substitution of GGT to AGT (aspartic acid). Tumors located in the upper third of the stomach had a significantly higher frequency of K-ras codon 12 mutations (3/8, 37.5%) compared with tumors located in the middle (4/29, 13.8%) or lower (3/99, 3.0%) thirds of the stomach (P = 0.001). No significant difference was observed in the frequency of K-ras codon 12 mutations in terms of other various clinicopathologic characteristics including tumor DNA ploidy and S-phase fraction. After a median follow-up of 26 months, disease free and overall survival were not significantly different between patients with stomach cancer with or without K-ras codon 12 mutation. Among eight patients with stomach cancer located in the upper part of the stomach, none of the three patients with K-ras gene-mutated tumors died versus four of five with tumors without K-ras gene mutations (P = 0.064).

CONCLUSIONS

K-ras codon 12 point mutations are uncommon in stomach cancer (7.9%). There was significant correlation between K-ras mutations and vertical tumor location in the stomach, suggesting that different mechanisms may play a role in the pathogenesis of stomach cancer according to the location of tumors in the stomach.

Conserved Glu-181 and Arg-182 residues of Escherichia coli H(+)-ATPase (ATP synthase) beta subunit are essential for catalysis: properties of 33 mutants between beta Glu-161 and beta Lys-201 residues

Twenty-two mutants between beta Glu-161 and beta Lys-201 of Escherichia coli H(+)-ATPase beta subunit could grow by oxidative phosphorylation, but 11 other such mutants, beta Glu-181-->Gln, Asp, Asn, Thr, Ser, Ala, or Lys and beta Arg-182-->Lys, Ala, Glu, or Gln, could not. The beta Asp-181, beta Lys-182, and other defective mutants had 1.4, 1, and < 0.1%, respectively, of the wild-type membrane ATPase activity. Partially purified F1-ATPases from all mutants at positions 181 and 182, except for the beta Asp-181 and beta Lys-182 mutants, showed very low unisite catalysis. Purified F1-ATPases of the beta Gln-181 and beta Ala-181 mutants showed no multisite (or steady state) catalysis and slow unisite catalysis (< or = 1% of that of the wild type): their defects could be attributed to decreased catalytic rates (low k+2 and k-2). Changes of the k+2 and k-2 values in the beta Asp-181 enzyme, which showed detectable multi- and unisite catalysis, were less marked (27 and 21%, respectively, of wild-type rates). The beta Gln-182 enzyme showed defective catalysis (< or = 0.1% of the multi- and approximately 1% of the unisite catalyses of the wild type), whereas the beta Lys-182 enzyme showed 1 and 85% of the wild-type multisite and unisite catalytic rates, respectively. beta Lys-182 had wild-type values of k+2 and k-2, but beta Gln-182 had k+2 about 10-fold lower than that of wild type.(ABSTRACT TRUNCATED AT 250 WORDS)

Peptides corresponding to the region adjacent to His-94 in the small subunit of cytochrome b558 inhibit superoxide generation in a cell-free system from human neutrophils

Synthetic peptides corresponding to the region adjacent to His-94 in the small subunit of cytochrome b558 inhibited superoxide generation in a cell-free system. The shortest sequence that gave a half inhibitory concentration (IC50) lower than 50 microM was TRNYYVRAVL. Substitution of alanine for any of two tyrosine or central valine residues markedly increased IC50, thereby indicating that these residues are critical for the activity. Since the inhibition was observed when the peptide was added to the system before but not after the stimulation with sodium dodecylsulfate, the peptides seem to interact irreversibly with the cytochrome molecule and hinder electron transport or alternatively to interfere with the association between cytochrome b558 and cytosolic components.

Detection of the H1-j strain of Salmonella typhi among Korean isolates by the polymerase chain reaction

Salmonella typhi, the etiologic agent of typhoid fever, typically has only a phase-1 flagellar antigen, H1-d (fliC). While most strains of S. typhi have H1-d antigen, 10-20% of Indonesian isolates have been reported to possess H1-j antigen instead. To investigate the presence H1-j strains of S. typhi isolates in Korea, where typhoid fever is still a common infectious problem, we used the polymerase chain reaction (PCR) with a pair of oligonucleotides primers that specifically amplified the flagellin gene of S. typhi. Of 375 isolates of S. typhi tested, only one was shown to possess the H1-j antigen, which was shown by the presence of a 1,269-basepair fragment on agarose gel electrophoresis after the PCR. The isolate with the H1-j antigen was cultured from a Korean-Indonesian man who was already symptomatic in Indonesia and was thought to be an Indonesian strain. Because 375 strains tested in this study were collected from cases with typhoid fever in different regions of Korea during the period from 1986 to 1991, it could be concluded that the mutation rate to j antigen is negligible among S. typhi endemic in Korea.

The alpha/beta subunit interaction in H(+)-ATPase (ATP synthase). An Escherichia coli alpha subunit mutation (Arg-alpha 296-->Cys) restores coupling efficiency to the deleterious beta subunit mutant (Ser-beta 174-->Phe)

The Ser-beta 174 residue of the Escherichia coli H(+)-ATPase beta subunit has been shown to be near the catalytic site together with Gly-beta 149, Gly-beta 172, Glu-beta 192, and Val-beta 198 (Iwamoto, A., Park, M.-Y., Maeda, M., and Futai, M. (1993) J. Biol. Chem. 268, 3156-3160). In this study, we introduced various residues at position 174 and found that the larger the side chain volume of the residue introduced, the lower the enzyme activity became. The Phe-beta 174 mutant was defective in energy coupling between catalysis and transport, whereas the Leu-beta 174 mutant could couple efficiently, although both mutants had essentially the same ATPase activities (approximately 10% of the wild type). The defective energy coupling of the Phe-beta 174 mutant was suppressed by the second mutation (Arg-alpha 296-->Cys) in the alpha subunit. The Cys-alpha 296/Phe-beta 174 mutant had essentially the same membrane ATPase activity as the Phe-beta 174 single mutant when assayed under the conditions that stabilize the double mutant enzyme. These results indicate the importance of the alpha/beta interaction, especially that between the regions near Arg-alpha 296 and Ser-beta 174, for energy coupling in the H(+)-ATPase. The 2 residues (Ser-beta 174 and Arg-alpha 296) may be located nearby at the interface of the two subunits. About 1 mol of N-[14C]ethylmaleimide could bind to 1 mol of the alpha subunit of Cys-alpha 296/Phe-beta 174 or Cys-alpha 296 mutant ATPase, but could not inhibit the enzyme activity. This is the first intersubunit mutation/suppression approach to ATPase catalysis and its energy coupling.

Detection of Salmonella typhi in the blood of patients with typhoid fever by polymerase chain reaction

A polymerase chain reaction (PCR)-based test was developed for the detection of Salmonella typhi in the blood specimens from patients with typhoid fever. Two pairs of oligonucleotide primers were designed to amplify a 343-bp fragment of the flagellin gene of S. typhi. Amplified products were analyzed by agarose gel electrophoresis and Southern blot hybridization by using a 32P-labeled 40-base probe internal to the amplified DNA. The nested PCR with two pairs of primers could detect 10 organisms of S. typhi as determined by serial dilutions of DNA from S. typhi. The peripheral mononuclear cells from 11 of 12 patients with typhoid fever confirmed by blood culture were positive for DNA fragment of the flagellin gene of S. typhi, whereas 10 blood specimens of patients with other febrile diseases were negative. With the nested PCR, S. typhi DNAs were detected from blood specimens of four patients with suspected typhoid fever on the basis of clinical features but with negative cultures. We suggest that the PCR technique could be used as a novel diagnostic method of typhoid fever, particularly in culture-negative cases.

Domains near ATP gamma phosphate in the catalytic site of H+-ATPase. Model proposed from mutagenesis and inhibitor studies

The beta Gly-149 residue is in a glycine-rich sequence (Gly-Gly-Ala-Gly-Val-Gly-Lys-Thr; residues 149-156) of the Escherichia coli H(+)-ATPase (ATP synthase) beta subunit. Substitution of beta Gly-149 by Ser suppressed the effect of the beta Ser-174-->Phe mutation (Iwamoto, A., Omote, H., Hanada, H., Tomioka, N., Itai, A., Maeda, M., and Futai, M. (1991) J. Biol. Chem. 266, 16350-16355), suggesting that beta Gly-149 is located near beta Ser-174. In this study, we introduced different residues at position 149 and found that a single mutant beta Cys-149 was defective. The effect of beta Cys-149 mutation was suppressed by beta Gly-172-->Glu, beta Ser-174-->Phe, beta Glu-192-->Val, or beta Val-198-->Ala replacement. These results suggest that beta Gly-149, beta Gly-172, beta Ser-174, beta Glu-192, and beta Val-198 residues are located close together in the catalytic site. From these findings we propose a model of the catalytic site of the enzyme near the gamma phosphate moiety of ATP. F1 enzymes with the double mutations beta Cys-149/beta Glu-172, beta Cys-149/beta Phe-174, beta Cys-149/beta Val-192, and beta Cys-149/beta Ala-198 were less sensitive than wild-type F1 to dicyclohexylcarbodiimide and adenosine triphosphopyridoxal (an affinity analogue of ATP forming a Schiff base with the epsilon-amino group of beta Lys-155 or beta Lys-201), and became sensitive to N-ethylmaleimide in an ATP-protected manner. These results of inhibitor studies are consistent with the proposed model.

Inhibition of neurotransmitter and hormone transport into secretory vesicles by 2-(4-phenylpiperidino)cyclohexanol and 2-bromo-alpha-ergocryptine: both compounds act as uncouplers and dissipate the electrochemical gradient of protons

2-(4-Phenylpiperidino)cyclohexanol (AH-5183) and 2-bromo-alpha-ergocryptine, known inhibitors of the transport of acetylcholine and L-glutamate, respectively, into synaptic vesicles, inhibited the ATP-dependent uptake of dopamine in parallel with the dissipation of the electrochemical gradient of protons in chromaffin granule membrane vesicles. These compounds induced the release of accumulated dopamine from the vesicles. They also inhibited the ATP-dependent formation of the electrochemical gradient of protons in liposomes reconstituted with chromaffin H(+)-ATPase without affecting the activities for ATP hydrolysis, and ATP-dependent uptakes of dopamine, gamma-aminobutyrate, and glutamate into synaptic vesicles. These results indicated that 2-(4-phenylpiperidino)cyclohexanol and 2-bromo-alpha-ergocryptine acted as uncouplers in the secretory vesicles.