Kumiko Ito

Identification of vivianite formed on the roots of paddy rice grown in pots

Abstract An understanding of the phosphate (P) dynamics in paddy rice fields is the basis for improving P fertilizer efficiency and reducing P loss from paddy fields. During the ripening stage of rice plants cultivated in pots, we identified vivianite on the roots. We placed 3 kg of air-dried soil in a pot with coated urea (1 g N), coated potassium sulfate (1 g K2O) and granular superphosphate (1 g P2O5) as basal fertilizers. Three rice seedlings were transplanted into each pot and grown until the ripening stage under submergence outdoor conditions. The bulk soil showed a black color indicating the formation of amorphous FeS. According to the soil analysis data, the oxalate-extractable Fe content was much greater than the labile S and P contents, indicating that enough Fe(II) can be supplied to the S and P for the reaction. Bluish vivianite particles were observed on the roots using an optical microscope. Scanning electron microscopy revealed that the vivianite was an aggregate of platy crystals, and an energy dispersive X-ray analysis showed that Fe and P were the major elements in the crystal aggregates. The diffraction peak positions by the X-ray microdiffractometer were very close to the reported pattern for vivianite. Future research on the dynamics of P is expected based on vivianite formation in paddy field soils.

Antimicrobial activity of a bovine myeloid antimicrobial peptide (BMAP-28) against methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

A bovine myeloid antimicrobial peptide (BMAP-28) is a member of the cathelicidin family which is included in the innate immune system of mammals. Recently, there have been many studies about antimicrobial peptides. This study aims to clarify whether BMAP-28 has bactericidal activity against methicillin-resistant Staphylococcus aureus (MRSA) and compares its activity against methicillin-susceptible S. aureus (MSSA) and MRSA. We found that the peptide was effective in killing MRSA (minimal inhibitory concentration (MIC) range; 5-20 µg/mL). It was also revealed that MSSA (MIC range; 1.25-20 µg/mL) had two levels of susceptibility to BMAP-28. We also examined the effect of BMAP-28 on bacterial shape to visually show its activity. After exposure to the peptide, both MSSA and MRSA cells showed the morphological changes on their surfaces. Our results indicate that BMAP-28 is a promising candidate for medicine against drug-resistant bacteria.

Antimicrobial activity of tea catechin against canine oral bacteria and the functional mechanisms

Epigallocatechin gallate (EGCG) is the major polyphenolic compound of green tea. Polyphenolic compounds were extracted from the leaf of Camellia sinensis (Japanese green tea), and the minimum inhibitory concentration against canine oral bacteria was measured. Subsequently, we investigated the inhibitory effects of polyphenolic compounds and EGCG on the growth of canine oral bacteria. EGCG showed antimicrobial activity against a model bacterium, Streptococcus mutans. Our results indicate that EGCG can inhibit the growth and biofilm formation of S. mutans and that EGCG does not interact with streptococcal lipoteichoic acid (LTA). Furthermore, our findings suggest that EGCG interacts with other component(s) of the bacterial membrane aside from streptococcal LTA to inhibit biofilm formation and damage biofilms.

IMPROvEMENT IN TASTE SENSITIvITy FOLLOWING PULMONARy REhABILITATION IN PATIENTS WITh ChRONIC OBSTRUCTIvE PULMONARy DISEASE

OBJECTIVE Weight loss is common in patients with chronic obstructive pulmonary disease (COPD). Anorexia, postulated to be associated with alteration in taste sensitivity, may contribute to weight loss in these patients. Pulmonary rehabilitation is known to lead to improved exercise performance in patients with COPD. However, the relationship between pulmonary rehabilitation and taste sensitivity has not been evaluated. The objective of this study was to compare taste sensitivity before and after pulmonary rehabilitation in patients with COPD. DESIGN Single-group intervention trial. PATIENTS Twenty-two patients with COPD. METHODS The six-min walk distance (6MWD), COPD assessment test, body mass index, fat mass index, fat-free mass index and taste test were conducted before and after 4-week pulmonary rehabilitation. Taste sensitivity was evaluated using the filter-paper disc method for 4 taste stimuli. Taste stimuli were salty, sweet, sour, and bitter tastes. Taste sensitivity was evaluated before and after pulmonary rehabilitation using the taste recognition threshold. RESULTS Following pulmonary rehabilitation, the 6MWD, COPD assessment test, salty recognition threshold, sweet recognition threshold and bitter recognition threshold improved significantly, whereas there were no significant improvements in body mass index, fat mass index, fat-free mass index or sour recognition threshold. CONCLUSION Pulmonary rehabilitation may improve taste sensitivity in patients with COPD.

Expression of recombinant alpha and beta tubulins from the yew Taxus cuspidata and analysis of the microtubule assembly in the presence of taxol

Taxol was originally isolated from the yew Taxus brevifolia. Because taxol inhibits the depolymerization of microtubules, the presence of a self-resistance mechanism in Taxus spp. was hypothesized. The cloning of the cDNA for alpha and beta tubulins from Taxus cuspidata and those from the human embryonic kidney cell line HEK293T revealed that the 26Asp, 359Arg, and 361Leu residues in the human beta tubulin, which are important for taxol binding, were replaced with Glu, Trp, and Met in the beta tubulin of T. cuspidata, respectively. The microtubule assembly of the recombinant alpha and beta tubulins was monitored turbidimetrically, and the results clearly demonstrated that the microtubule from T. cuspidata is less sensitive to taxol than that from HEK293T cells. The Taxus microtubule composed of the wild-type alpha tubulin and the beta tubulin with the E26D mutation restored the sensitivity to taxol. We thus postulated that the mutation identified in the beta tubulin of T. cuspidata plays a role in the self-resistance of this species against taxol. Graphical Abstract Monitoring of microtubule assembly in the absence and presence of taxol suggests that the beta tubulin of T. cuspidata is tolerant of taxol.

Inhibitory effect of cervical trachea and chest wall vibrations on cough reflex sensitivity and perception of urge-to-cough in healthy male never-smokers

BackgroundNon-pharmacological options for symptomatic management of cough are desired. Although chest wall mechanical vibration is known to ameliorate cough reflex sensitivity, the effect of mechanical vibrations on perceptions of urge-to-cough has not been studied. Therefore, we investigated the effect of mechanical vibration of cervical trachea, chest wall and femoral muscle on cough reflex sensitivity, perceptions of urge-to-cough as well as dyspnea.MethodsTwenty-four healthy male never-smokers were investigated for cough reflex sensitivity, perceptions of the urge-to-cough and dyspnea with or without mechanical vibration. Cough reflex sensitivity and urge-to-cough were evaluated by the inhalation of citric acid. The perception of dyspnea was evaluated by Borg scores during applications of external inspiratory resistive loads. Mechanical vibration was applied by placing a vibrating tuning fork on the skin surface of cervical trachea, chest wall and femoral muscle.ResultsCervical trachea vibration significantly increased cough reflex threshold, as expressed by the lowest concentration of citric acid that elicited five or more coughs (C5), and urge-to-cough threshold, as expressed by the lowest concentration of citric acid that elicited urge-to-cough (Cu), but did not significantly affect dypnea sensation during inspiratory resistive loading. On the other hand, the chest wall vibration not only significantly increased C5 and Cu but also significantly ameliorated the load-response curve of dyspnea sensation.ConclusionsBoth cervical and trachea vibrations significantly inhibited cough reflex sensitivity and perception of urge-to-cough. These vibration techniques might be options for symptomatic cough management.

Elemental affinity for siderite found in a Japanese paddy subsoil

ABSTRACT Siderite (FeCO3), a type of carbonate mineral, is very occasionally recognized as a nodule in anoxic soils and sediments. During siderite formation, elements are expected to be accumulated or excluded between siderite and bulk soil. Therefore, we verified the affinity of 40 elements for siderite found in the gley horizon of a smectite-rich paddy field in northeastern Japan from the elemental concentration of the soil and the siderite dissolved in 2.88 mol L−1 hydrochloric acid (10% HCl). The concentration ratio of the target element of the soil to the siderite was expressed by the product of the dimensionless R0 value and ratio of titanium (Ti) concentration of the soil to the siderite (Csiderite /Csoil) = R0 (Tisiderite /Tisoil). The affinity of each element for the siderite was analyzed by comparing the R0 values. In comparison with Ti used as the reference element, P, Cr, Co and Mo were accumulated (R0 > 1.0), and alkali metals, such as Li, Na and K, and chalcophile elements, such as Cu, Zn, Cd and Pb, tended to be equal or excluded from the siderite (R0 ≦1.0). Of the group 2 elements, Ca, Sr and Ba were accumulated, while Mg was excluded. The affinity of Mn for siderite exceeded that of Fe as the main component of the siderite, which reflects the fact that siderite was formed in a fresh water condition. The siderite size did not influence the elemental affinity. Observation of micromorphology using a scanning electron microscope showed that the siderite nodules were aggregations of siderite particles and clays, suggesting that the siderite grew by taking in clay around it. The rare earth element (REE) distribution pattern showed a tendency not to increase linearly but to increase with forming a concave curve at the intervals of the four elements with the increase of atomic number (i.e. tetrad effects). Although these findings are from the lower horizons of anoxic soils, the elemental affinity for siderite of this study is useful in order to elucidate the complex elemental dynamics in the anoxic environment.

Effect of Short-Term Exposure to High Particulate Levels on Cough Reflex Sensitivity in Healthy Tourists: A Pilot Study

Background: Previous studies have reported a relationship between particulate air pollution and respiratory symptoms or decline in lung function, but information about acute effects of short-term exposure to airborne particulate matter (PM) on cough and pulmonary function is scarce. Objective: To investigate the effect of short-term exposure to high concentrations of PM on the cough reflex threshold, urge-to-cough, pulmonary function, and cough-related quality of life in a group of healthy non-resident volunteers visiting Beijing, China. Methods: Seventeen healthy residents of Sendai, Japan, who planned to attend a meeting in Beijing, were recruited. We checked local air quality and measured cough reflex thresholds, urge-to-cough, pulmonary function, and Leicester Cough Questionnaire-acute (LCQ-acute) scores in the volunteers before, during, and after their trip to Beijing. Results: The PM2.5 and PM10 concentrations in Beijing were significantly higher than those in Japan on the measurement days. Cough reflex thresholds, expressed as nebulized citric acid concentrations required to induce ≥ 2 and ≥ 5 coughs, were significantly lower during the stay in Beijing than before or after the visit. Vital capacity, forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC were significantly lower during the stay in Beijing than before the trip. Similarly, the urge-to-cough threshold was significantly lower during the stay in Beijing than after the trip, as was the total LCQ-acute score. Conclusion: We tentatively concluded that short-term exposure to high PM concentrations may have adverse effects on cough reflex and urge-to-cough thresholds, pulmonary function, and cough-related quality of life.

Gender differences in the effect of urge‐to‐cough and dyspnea on perception of pain in healthy adults

Previous studies have reported that respiratory sensations, such as urge‐to‐cough and dyspnea, have an inhibitory effect on pain. Considering the existence of gender differences in both urge‐to‐cough and pain, it is conceivable that a gender difference also exists in the analgesia induced by urge‐to‐cough. In this study, we evaluated gender differences in the pain perception response to urge‐to‐cough, as well as to dyspnea. Twenty‐seven male and 26 female healthy nonsmokers were originally enrolled. Citric acid challenge was used to induce the urge‐to‐cough sensation, and dyspnea was elicited by inspiratory loaded breathing. Before and during inductions of these two respiratory sensations, perception of pain was assessed by the thermal pain threshold, and differences between men and women were compared. The thermal pain threshold in women (43.83 ± 0.17°C) was significantly lower than that in men (44.75 ± 0.28°C; P < 0.05) during the baseline period. Accompanying increases in both citric acid concentration and inspiratory resistive load, thermal pain threshold values significantly increased in both men and women. The average thermal pain threshold changes for comparable increases in the urge‐to‐cough Borg score were parallel between men and women. Furthermore, the mean value of the thermal pain threshold plotted against the dyspnea Borg score also showed no significant gender difference. These results demonstrate that although gender differences exist in respiratory sensations, that is, urge‐to‐cough and dyspnea, the inhibitory effects of these respiratory sensations on the perception of pain are not significantly different between the sexes.

Identification of a novel mechanism of action of bovine IgG antibodies specific for Staphylococcus aureus

Staphylococcus aureus is a major pathogen that causes subclinical mastitis associated with huge economic losses to the dairy industry. A few vaccines for bovine mastitis are available, and they are expected to induce the production of S. aureus-specific antibodies that prevent bacterial adherence to host cells or promote opsonization by phagocytes. However, the efficacy of such vaccines are still under debate; therefore, further research focusing on improving the current vaccines by seeking additional mechanisms of action is required to reduce economic losses due to mastitis in the dairy industry. Here, we generated S. aureus-specific bovine IgG antibodies (anti-S. aureus) that directly inhibited bacterial growth in vitro. Inhibition depended on specificity for anti-S. aureus, not the interaction between Protein A and the fragment crystallizable region of the IgG antibodies or bacterial agglutination. An in vitro culture study using S. aureus strain JE2 and its deletion mutant JE2ΔSrtA, which lacks the gene encoding sortase A, revealed that the effect of anti-S. aureus was sortase-A-independent. Sortase A is involved in the synthesis of cell-wall-associated proteins. Thus, other surface molecules, such as membrane proteins, cell surface polysaccharides, or both, may trigger the inhibition of bacterial growth by anti-S. aureus. Together, our findings contribute insights into developing new strategies to further improve the available mastitis vaccine by designing a novel antigen on the surface of S. aureus to induce inhibitory signals that prevent bacterial growth.