• Title/Summary/Keyword: size diversity

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Diversity of Bacteriophages Infecting Xanthomonas oryzae pv. oryzae in Paddy Fields and Its Potential to Control Bacterial Leaf Blight of Rice

  • Chae, Jong-Chan;Nguyen, Bao Hung;Yu, Sang-Mi;Lee, Ha Kyung;Lee, Yong Hoon
    • Journal of Microbiology and Biotechnology
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    • v.24 no.6
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    • pp.740-747
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    • 2014
  • Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

Classification of Microhabitats based on Habitat Orientation Groups of Benthic Macroinvertebrate Communities (저서성 대형무척추동물의 서식 특성에 따른 미소서식처 유형화)

  • Kim, Jungwoo;Kim, Ah Reum;Kong, Dongsoo
    • Journal of Korean Society on Water Environment
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    • v.33 no.6
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    • pp.728-735
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    • 2017
  • Many restoration projects are underway to revive disturbed streams. In order to achieve successful stream restoration, a variety of microhabitats should be created to promote biological diversity. Research on biological classification of microhabitats is essential for biological diversity. However, research on classification using only physical environmental factors has been carried out. The purpose of this study is to classify and quantify the microhabitat of the stream by using macroinvertebrates systematically. In this study, eight wadeable streams and four non-wadeable streams were surveyed to identify the benthic macroinvertebrates in these various microhabitats. Among the physical environmental factors (current velocity, water depth, substrate), the particle size of the substrate was the most influential factor in the emergence of the Habitat Orientaion Groups. Among the HOGs, clinger and burrower were highly correlated with physical environment factors and showed the opposite tendency. The distribution of clinger and burrower according to the physical environmental factors showed two tendencies based on the current velocity (0.3 m/s) and water depth (0.4 m). In addition, the particle size of the substrate showed three trends (${\leq}-5.0$, -5.0 < mean diameter ${\leq}-2.0$, > -2.0). Based on the abundance tendency of these two HOGs, the microhabitats were classified into nine types, from a eupotamic microhabitat to a lentic microhabitat. Classification of the microhabitats using HOGs can be employed for creating microhabitats to promote biological diversity in future stream restoration plans.

Importance-Performance Analysis of Multiplex Cinema Attributes (멀티플랙스 영화관 선택속성의 중요도-성취도 분석)

  • Kim, Jae-Hong;Ko, Seon-Hee
    • The Journal of the Korea Contents Association
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    • v.18 no.1
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    • pp.587-595
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    • 2018
  • This research aims to analyze the importance-performance among multiplex cinema selection attributes. Therefore, we collected data for visitors who visited the multiplex cinema and want to watch movies. Of the various multiplex cinema selection attributes, four factors were deduced that includes: major services, human services, physical environment, auxiliary services using exploratory factor analysis. In the quadrant I, the area of 'Concentrate Here' was 'diversity of screening time', 'diversity of movie genre', 'convenience of mobile app use', 'size and convenience of parking facility'. In the quadrant II, 'Keep up the Good Work' area was 'convenience of website booking', 'discounts through card partnerships', 'employee friendliness', 'accurate employee information delivery', 'comfortable seating', 'screen size', 'cinematic sound quality', and 'convenience of traffic' etc. The quadrant III, 'Low Priority' appeared to be 'membership system', 'tidiness of staff attire', 'resting space for waiting time', 'accessibility to the neighboring area', 'diversity of the snack corner', and 'overall cleanliness' etc. The quadrant IV, 'Possible Overkill' was 'appropriateness of the auditorium temperature' and 'service proficiency'.

A Study on Sizing System for Mail-Order Clothing (통신판매의류의 치수에 대한 조사 연구)

  • 박경화;천종숙
    • Journal of the Korean Society of Clothing and Textiles
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    • v.20 no.1
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    • pp.43-53
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    • 1996
  • This study was initiated to investigate (1) the current sizing system for mail-order clothing, (2) consumers' preference for sizing systems, and (3) consumers' satisfaction with garment size. The apparel items and the sizes available at various mail-order companies in Korea were also reviewed. This investigation of consumers' preferences for various size description systems includes a survey of 410 men and women who had purchased garments by mail-order. The data were analyzed by Statistical Analysis System/pc. The major results are as follows; 1. The sizing system of mail-order clothing was different by garment items. The number of apparel sizes available for mail-order purchasing was three or less. The most mail∼order garments were labeled by the numerical size codes of body girth nleasurements or letter code (S, M, L). 2. The size description system most prefered by female subjects(N : 360) was the numerical size code of a body measurement(55.4%). The combination of bust-hips-height measurements size codes were prefered by 13.3% . The pictogram was least premiered by the subjects. 3. The apparel items that subjects wanted to buy using mail-order were underwear, home -weat and night-wear. The heavy users of mail-order purchasing, however, also wanted to purchase expensive garments requiring precise fit. The subjects aged from 20's to 80's wanted to purchase childern's wear by mail. 4. The desire for diversity of garment item and size of mail-order apparel was relatively high. The subjets also wanted to purchase special size garments by mail-order, e. g., garment sizes for full or tall figure.

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Determination on the Optimal Sample Size in the Aquatic Insect Community Analysis - Pangtae Creek Model (수서곤충 군집분석에 있어서 최적표본크기의 결정 - 방태천 모형)

  • 윤일병;노태호;이성진;박재홍;배연재
    • The Korean Journal of Ecology
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    • v.21 no.5_1
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    • pp.409-418
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    • 1998
  • A molel study was conducted to determine the optimal sample size for the analysis of the aquatic insect community in a stream reach of the Pangtae Creek, Kangwon-do in October 1995 and may 1996. The results showed that the required minimum sample size varied and depended on the purposes of the community analysis. Acoording to the Species: Area Curve method, at least 16 Surber samplings ($30{\times}30cm$) were required in a stream reach in each spring and fall survey. The species diversity index did not vary significantly as the sample size increased. Based on the coefficient of variation analysis, the minimum sample sizes of 10 were required in order to compare seasonal differences of the community in the study area. Considering the static community structure of aquatic insects, including both species numbers and individual numbers of aquatic insects, 11 and 7 samplings were optimal sizes for the fall and spring survey, respectively. We concluded that 12 Surber samplings from 3 riffle-pool sequences (4 samplings at each riffle-pool sequence) would be required in a stream reach (length 1 km) to obtain reliable as well as cost efficient data. Our model showed that the optimal sample size should be determined by interactions between minimum sample size, the degree of data reliability, and cost efficiency.

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Effects of Acidification on the Changes of Microbial Diversity in Aquatic Microcosms

  • Young-Beom Ahn;Hong-Bum Cho;Byung Re Min;Yong-Keel Choi
    • Animal cells and systems
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    • v.3 no.2
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    • pp.153-159
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    • 1999
  • In an artificial pH-gradient batch culture system, the effects of acidification on the species composition of a heterotrophic bacterial community were analyzed. As a result of this study, it was found that total bacteria numbers were not affected by acidification and that the population of hetero-trophic bacteria decreased as pH became lower. The heterotrophic bacteria isolated from the entire pH gradient were 12 genera and 22 species. Among them, 64% were gram negative and 36% were gram positive bacteria. As pH decreased, the distribution rate of gram negative bacteria increased while that of gram positive bacteria decreased. The diversity of genera decreased from 13 to 5 as pH decreased from 7 to 3. The G+C content of all of the 202 isolated strains varied from 22.8 to 77.0%, and increased in interspecies of same genus as pH decreased. As a result of clustering analysis, the diversity index of species ranged from 1.13 to 2.37, and it had lower indices as pH decreased. In order to evaluate the diversity of numbers of sample of different size, a rarefaction method was used to analyze the expected number of species appearance according to pH. The statistical significance of species diversity was verified by the fact that the number decreased at lower pH.

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ISSR Markers of Authentication for Korean and Chinese Platycodon Grandiflorum

  • Shin, Soon-Shik;Choi, Ju-Soo;Huh, Man-Kyu
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.23 no.1
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    • pp.214-218
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    • 2009
  • Platycodon grandiflorum is a long-lived herbaceous and one of the very important herbal medicine and foods. P. grandiflorum is called do-ra-ji in Korea. Inter-simple sequence repeats (ISSR) markers were performed in order to analyse the phenetic relationships of four accessions of P. grandiflorum. Wild groups had higher expected diversity, 0.164 for Korean and 0.157 for Chinese accessions than those of cultivated groups, 0.079 for Korea and 0.059 for China. The total genetic diversity in P. grandiflorum was 0.268 across species and the value was lower than average values for species with similar life history traits. The patchy distribution and domestication are proposed as possible factors contributing to low genetic diversity. An assessment of the proportion of diversity within species, HAccession/HSpecies, indicated that about 57.1% the total genetic diversity was among species. Thus, the majority of genetic variation (42.9%) resided within accessions. The estimated Nm (the number of migrants per generation) was very low among four accessions (mean Nm = 0.376). The low estimate of Nm indicated that gene flow was not extensive among four accessions. ISSR01-02 locus can be recognized as an unique locus of Korean groups (wild and cultivated accessions). Thus the locus can be used to distinguish Korean accessions from Chinese accessions. ISSR04-06 locus was found specific to Chinese groups (wild and cultivated accessions) and was not shown in Korean accessions. Although the size of sampling was not large enough for P. grandiflorum, the analyses of ISSRs will certainly provide an enhanced view on the phylogeny of accessions.

Genetic diversity analysis of Thai indigenous chickens based on complete sequences of mitochondrial DNA D-loop region

  • Teinlek, Piyanat;Siripattarapravat, Kannika;Tirawattanawanich, Chanin
    • Asian-Australasian Journal of Animal Sciences
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    • v.31 no.6
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    • pp.804-811
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    • 2018
  • Objective: Complete mtDNA D-loop sequences of four Thai indigenous chicken varieties, including Pra-dhu-hang-dam (PD), Leung-hang-khao (LK), Chee (CH), and Dang (DA) were explored for genetic diversity and relationships with their potential ancestor and possible associates to address chicken domestication in Thailand. Methods: A total of 220 complete mtDNA D-loop sequences of the four Thai indigenous chicken varieties were obtained by Sanger direct sequencing of polymerase chain reaction amplicons of 1,231 to 1,232 base pair in size. A neighbor-joining dendrogram was constructed with reference complete mtDNA D-loop sequences of Red Junglefowl (RJF) and those different chicken breeds available on National Center for Biotechnology Information database. Genetic diversity indices and neutrality test by Tajima's D test were performed. Genetic differences both within and among populations were estimated using analysis of molecular variance (AMOVA). Pairwise fixation index ($F_{ST}$) was conducted to evaluated genetic relationships between these varieties. Results: Twenty-three identified haplotypes were classified in six haplogroups (A-E and H) with the majority clustered in haplogroup A and B. Each variety was in multiple haplogroups with haplogroups A, B, D, and E being shared by all studied varieties. The averaged haplotype and nucleotide diversities were, respectively 0.8607 and 0.00579 with non-significant Tajima's D values being observed in all populations. Haplogroup distribution was closely related to that of RJF particularly Gallus gallus gallus (G. g. gallus) and G. g. spadiceus. As denoted by AMOVA, the mean diversity was mostly due to within-population variation (90.53%) while between-population variation (9.47%) accounted for much less. By pairwise $F_{ST}$, LK was most closely related to DA ($F_{ST}=0.00879$) while DA was farthest from CH ($F_{ST}=0.24882$). Conclusion: All 4 Thai indigenous chickens are in close relationship with their potential ancestor, the RJF. A contribution of shared, multiple maternal lineages was in the nature of these varieties, which have been domesticated under neutral selection.

Impact Assessment Model of Bird Species for Land Developments (개발사업에 따른 조류종 영향평가모형 개발 및 적용)

  • Lee, Dong-Kun;Kim, Eun-Young;Lee, Eun-Jae;Song, Won-Kyong
    • Journal of Environmental Impact Assessment
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    • v.19 no.3
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    • pp.347-356
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    • 2010
  • Forests are being seriously fragmented as a result of land development. Land development with disregard to its subsequent environmental impacts is a primary threat to biodiversity by incurring massive habitat losses and changes in structure and composition of forests. The purpose of this study was to develop the impact assessment model for quantitative distance or degree of disturbance by land developments. This study conducted a survey about structure and composition of forest species to determine degree of impact from land development. The edge effect of forest fragmentation on the number of bird species, population size, and bird diversity was obvious. In particular, the bird diversity sharply declines around the forest edge where intensive land development projects take place. To assess the disturbance of forest species, the factors selected were the bird diversity and the rate of edge species. The impact assessment model about bird diversity was explained by type of forest fragmentation and type of vegetation ($R^2$=0.23, p<0.005). The other model about edge species explained by a distance, type of forest fragmentation, type of vegetation, and width of road ($R^2$=0.34, p<0.001). In order to test the applicability of the model developed in this study, the models was applied to the Samsong housing development in Goyang-si, Gyunggi-do. The impacts of land development on the bird species were reasonably quantified to suggest effective mitigation measure. The impact assessment model developed in this study is useful to assess the magnitude of disturbance of bird species. Particularly, the model could be applied to the current Environmental Impact Assessment practices to predict and quantify the impacts of land developments projects on forest bird species.

Development of EST-SSR Markers for Evaluation of Genetic Diversity and Population Structure in Finger Millet (Eleusine coracana (L.) Gaertn.)

  • Lee, Myung Chul;Choi, Yu-Mi;Hyun, Do-Yoon;Lee, Sukyeung;Kim, Jin-Hee;Oh, Sejong
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2018.04a
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    • pp.105-105
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    • 2018
  • Finger millet, Eleusine coracana Gaertn., is more nutritious than other cereals and millets and widely cultivate in tropical regions of the world. However, status of its genetic diversity remained concealed due to lack of research work in this species. In recent years, microsatellites have become the most used markers for studying population genetic diversity. In present study, genetic diversity and structure of different populations of finger millet from Africa and South Asia was examined at molecular level using newly developed EST-Simple Sequence Repeat (EST-SSR) markers using a total of 1,927 ESTs of Eleusine coracana available in the NCBI database. In total, 46 primers produced 292 alleles in a size range of 100-500 bp and mean Polymorphism Information Content (PIC) and Marker Index (MI) were 0.372 and 1.04, respectively. 46 primers showed polymorphism and 21 primers were identified as having a PIC value above 0.5. Principal coordinates analysis and the dendrogram constructed out of combined data of both markers showed grouping of finger millet accessions to their respective area of collection. The 156 accessions was classified into four groups, such as three groups of Africa collection and one group of Asia. Results of present study can be useful in identifying diverse accessions and management of this plant resource. Moreover, the novel SSR markers developed can be utilized for various genetic analyses in this species in future.

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