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Cooperative DnaA Binding to the Negatively Supercoiled datA Locus Stimulates DnaA-ATP Hydrolysis
No full textTimely initiation of replication in Escherichia coli requires functional regulation of the replication initiator, ATP-DnaA. The cellular level of ATP-DnaA increases just before initiation, after which its level decreases through hydrolysis of DnaA-bound ATP, yielding initiation-inactive ADP-DnaA. Previously, we reported a novel DnaA-ATP hydrolysis system involving the chromosomal locus datA, and named it datA-dependent DnaA-ATP hydrolysis (DDAH). The datA locus contains a binding site for a nucleoid-associating factor IHF and a cluster of three known DnaA-binding sites, which are important for DDAH. However, the mechanisms underlying the formation and regulation of the datA-IHF-DnaA complex remain unclear. We now demonstrate that a novel DnaA box within datA is essential for ATP-DnaA complex formation and DnaA-ATP hydrolysis. Specific DnaA residues, which are important for interaction with bound ATP and for head-to-tail inter-DnaA interaction, were also required for ATP-DnaA-specific oligomer formation on datA. Furthermore, we show that negative DNA supercoiling of datA stabilizes ATP-DnaA oligomers, and stimulates datA-IHF interaction and DnaA-ATP hydrolysis. Relaxation of DNA supercoiling by addition of novobiocin, a DNA gyrase inhibitor, inhibits datA function in cells. On the basis of these results, we propose a mechanistic model of datA-IHF-DnaA complex formation and DNA supercoiling-dependent regulation for DDAH
A Preselection-Based Fast Support Vector Machine Learning for Large-Scale Pattern Sets using Compressed Relative Neighborhood Graph
No full textWe propose a pre-selection method for training support vector machines (SVM) with a largescale dataset. Specifically, the proposed method selects patterns around the class boundary and the selected data is fed to train an SVM. For the selection, that is, searching for boundary patterns, we utilize a compressed representation of relative neighborhood graph (Clustered-RNG). A Clustered-RNG is a network of neighboring patterns which have a different class label and thus, we can find boundary patterns between different classes. Through large-scale handwritten digit pattern recognition experiments, we show that the proposed pre-selection method accelerates SVM training process 10 times faster without degrading recognition accuracy
Damage micromechanisms in dual-phase steel investigated with combined phase- and absorption-contrast tomography
No full textThe single-distance phase retrieval technique was applied to contrast-enhanced imaging of the dual-phase microstructure of a ferrite/martensite dual-phase with only 1.4% difference in density between the two phases. Each high-resolution absorption-contrast image was registered with a corresponding phase-contrast image, to analyse damage evolution behaviour. The loading step at which each microvoid was nucleated was identified by tracking the microvoid throughout tension, together with its nucleation site. Premature damage initiation was observed at a relatively early stage at various nucleation sites, such as the ferrite interior, martensitic interior and ferrite/martensite interfaces; however, the subsequent growth of such microvoids was relatively moderate. On the other hand, microvoids were also initiated later due to martensitic cracking after the maximum load was reached, and these microvoids subsequently exhibited rapid growth. The martensite cracking induced additional damage evolution mainly along nearby ferrite/martensite interfaces and intersections between the martensite and the ferrite grain boundary. It is notable that the microvoids originating from martensitic cracking exhibited characteristic shear-dominated growth under macroscopic tension, whereas those originating from the other nucleation sites exhibited traditional triaxiality-dominated growth. It was concluded that the ductile fracture was dominated by the substantial force driving the growth of microvoids located on morphologically characteristic martensitic particles
Nested PCR–based Assay for Diagnosis of Circular Leaf Spot Disease–causing Mycosphaerella nawae and its Application
No full textIn this study, we developed a nested PCR detection method based on draft genomic sequences of Mycosphaerella nawae and then applied the method to survey primary symptoms of circular leaf spot (CLS) and the seasonal ascospore scattering period. To develop the assay for detecting the fungus, 11 primers for the initial PCR and 19 primers for the nested PCR were designed (based on the glycoside hydrolase family 3 gene) using draft genomic sequences of M. nawae. Consequently, the primer pairs Mn–F1/ Mn–R1 and Mn–nes–168f/Mn–nes–483r were selected and their specificities examined using regional M. nawae isolates, various healthy persimmon leaves, other fungal pathogens of persimmon, and allied species of M. nawae. Furthermore, the developed nested PCR method was applied for the diagnosis of the initial stage of CLS using both diseased and asymptomatic leaves. Additionally, scattered M. nawae ascospores collected by a spore sampler were surveyed from May to November 2015. Therefore, it is assumed that the nested PCR method can suggest the proper fungicide spraying period for CLS through anticipation of the ascospore quantity, and the early diagnosis of CLS will enable control of its development on persimmon
Effects of Weather Factors on Fuel Moisture Contents of Forestland in Chuncheon, South Korea
No full textFuel moisture contents in the forest floor are one of important factors for forest fire spread due to their role as a possible fire ignition and are closely related to changes in weather factors. In the present study, we analyzed changes in forest fuel moisture content for two tree species (Pinus densiflora and Quercus dentata) associated with two different weather measurement data (in–situ measurement within the forest and observation at the weather station) during three consecutive years of monitoring including the Korean forest fire danger seasons (spring and fall). Results showed that the weather data from in–situ measurement within the forest and the CWS (Chuncheon Weather Station) had different patterns in that average temperature and max temperature tended to be higher in the forest, while min temperature had lower in the forest. These different patterns in weather factors affected the dead forest fuel moisture content thereby causing differences in the forest fuel moisture content among species. Results also revealed significant relation between precipitation and forest fuel moisture content indicating forest fuel moisture content decreases significantly after precipitation events during both seasons. The present study suggests that weather data within the forest which can reflect regional weather characteristics must be acquired to more accurately determine the forest fuel moisture content. Especially in Korea where most of the land consists mainly mountainous forestland. Hence, it is necessary to conduct future research which comprises comparative analysis of various leaf types based on dynamic changes of in–situ weather factors within the forest and monitor precise moisture content changes by leaf type after precipitation in order to ensure the accuracy of forest fire prediction systems during the forest fire danger season
Genetic Diversity and Sectional Relationships from an Amplified Fragment Length Polymorphism Analysis of Taiwan Bananas
No full textPhylogenetic relationships among 19 Musa species or cultivars were examined through DNA fingerprinting with amplified fragment length polymorphism (AFLP) analysis. The AFLP analysis was performed on the Musa species or cultivars with 21 primer combinations, yielding a total of 6,348 DNA bands, among which 6,113 (96.3%) were polymorphic. M. itinerans var. formosana demonstrated 133 monomorphic bands, which is the most among all samples. Unweighted pair–group method with arithmetic averages was used as a cluster program to divide M. itinerans, M. acuminate, M. balbisiana and 16 cultivars into different major groups. The genetic similarity coefficient among all the species was 0.23. Bananas with the A genome were clustered into the same major group. The similarity coefficients of ‘Pei Chiao’ with ‘Giant Cavendish’ (0.99) and ‘Dwarf Cavendish’ (0.97) indicated that these cultivars share a strong phylogenetic relationship. Within the primer combination of E–TAC/M–GTC, the fingerprint pattern of ‘Pei Chiao’ was compared with that of ‘Giant Cavendish’ and ‘Dwarf Cavendish’ to show two polymorphic bands of 255 and 238 bp. Although ‘Pei Chiao’ with the AAA genome was highly similar in genetic constitution to ‘Giant Cavendish’ and ‘Dwarf Cavendish’, it still can be discriminated from its close relatives according to the information of few polymorphic fragments. In addition, the phylogenetic analysis results revealed that the genetic organization of native Taiwan species, M. itinerans var. formosana, differed significantly from that of the other banana species. The findings of this study may facilitate germplasm identification and genetic breeding of banana species and cultivars
An experimental study for the improvement of mental health by use of a smartphone application at Kyushu University : Basic design and future plans
No full textAccording to a statement issued by the Ministry of Health, Labour and Welfare, suicide is the leading cause of death for Japanese people in their 20s. Although many university students have serious mental health problems, they hesitate to consult psychiatrists and counselors. There are several reasons why young people end their lives without consulting anyone. The following are a few examples. (1) They do not pay attention to their own mental health ; (2) They do not know any consultation systems, including medical services ; and (3) They are embarrassed to consult with others about personal problems. In order to improve this situation, whereby university students seldom use consulting systems, we launched a new project “Experimental study for the improvement of mental health by use of a smartphone application at Kyushu University,” because smartphones are now an inextricable part of university students’ lives. In this article, we introduce the outline of this project, which includes the design of a smartphone application, and our future development plans
Can social networking services assist with borderline personality disorder? : An evaluation of two case reports
No full textCompared to cases in the past, instances of borderline personality disorder currently appear to be less severe. Meanwhile, Social Networking Services (SNSs) have become popular among young people and their use affects the lifestyles of both those suffering from mental disorders and those who are not. In this article, two case reports are used to outline the strong affinity that people with borderline personality disorder have with SNSs. In particular, SNSs were found to buffer clashes of feelings among users, provide abundant objects on which users can depend, and provide a space for self-display. While these features may have positive effects on borderline personality disorder, we should also be careful about the negative effects, such as Internet addiction and sexting. Further case reports and research in the relationships between SNSs and borderline personality disorder are needed to ascertain whether SNSs are beneficial for borderline personality disorder treatment
