• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.373-382
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• 2020

Candidatus Carsonella ruddii is an endosymbiont that resides in specialized cells within the body cavity of plant sap-feeding insects called psyllids. The establishment of symbiotic associations is considered one of the key factors for the evolutionary success of psyllids, as it may have helped them adapt to imbalanced food resources like plant sap. Although C. ruddii is defined as a psyllid primary symbiont, the genes for some essential amino acid pathways are absent. Complete genome sequences of several C. ruddii strains have been published. However, in-depth intra-species comparison of C. ruddii strains has not yet been done. This study therefore aimed to perform a comparative genome analysis of six C. ruddii strains, allowing the interrogation of phylogenetic group, functional category of genes, and biosynthetic pathway analysis. Accordingly, overall genome size, number of genes, and GC content of C. ruddii strains were reduced. Phylogenetic analysis based on the whole genome proteomes of 30 related bacterial strains revealed that the six C. ruddii strains form a cluster in same clade. Biosynthetic pathway analysis showed that complete sets of genes for biosynthesis of essential amino acids, except tryptophan, are absent in six C. ruddii strains. All genes for tryptophan biosynthesis are present in three C. ruddii strains (BC, BT, and YCCR). It is likely that the host may depend on a secondary symbiont to complement its deficient diet. Overall, it is therefore possible that C. ruddii is being driven to extinction and replacement by new symbionts.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.111-114
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• 1978

The red tide that occurred in Jinhae Bay in the middle of July, 1977 was caused by the microscopic dinoflagellate, Gonyaulax sp. , which is very similar to G. catenella. The cell is round, dorsoventrally flat and transdiameter is about $40\;\mu$. Many cells are chained. Dark brown, band and streak-like patches were formed in the surface water. A great deal of jelly fishes, Chrysaora quinquecirrha and Aurelia aurita, appeared in the red tide area and its surrounding waters. The number of cells was high, being $5.0\times10^5\;cells/\iota$ and among them Gonyaulax sp., predominant species, was $84.8\%$ in maximum. Transparency was less than 1 m in patches. In the surface water, temperature was $25.0^{\circ}C$, chlorinity $17.8%_{\circ}$ and dissolved oxygen $8.11m\iota/\iota\;(180\%)$ during daytime. Red tide stayed for a week. Some oysters were found damaged after the extinction of the red tide but their interrelationship was not found.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.46-53
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• 1993

The kinetic and equilibrium characteristics of copper extraction by salicylaldoxime in chloroform and benzene were investigated. Equilibrium constants such as dissociation constant, distribution coefficient of salicylaldoxime and stability constant, distribution coefficient and molar extinction coefficient of oxime-Cu chelate were determined from absorbance. Extracted species of Cu-chelate were found to be ${\bar{CuR_2}}$. Overall initial extraction rate of copper by salicylaldoxime in chloroform was expressed by the following equation : $R=k[Cu^{2+}]{\bar{[HR]}}^{0.5}/[H^+]^{0.4}$.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.73.2-73.2
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• 2011

We present a new database of absorption and emission-line measurements based on the entire spectral atlas from the Sloan Digital Sky Survey (SDSS) 7th data release of galaxies within a redshift of 0.2. Our work makes use of the publicly available penalized pixel-fitting(pPXF) and gas and absorption line fitting (gandalf) IDL codes, aiming to improve the existing measurements for stellar kinematics, the strength of various absorption-line features, and the flux and width of the emissions from different species of ionized gas. Our fit to the stellar continuum uses both standard stellar population models and empirical templates obtained by combining a large number of stellar spectra in order to fit a subsample of high-quality SDSS spectra for quiescent galaxies. Furthermore, our fit to the nebular spectrum includes an exhaustive list of both recombination and forbidden lines. Foreground Galactic extinction is implicitly treated in our models, whereas reddening in the SDSS galaxies is included in the form of a simple dust screen component affecting the entire spectrum that is accompanied by a second reddening component affecting only the ionised gas emission. Most notable of our work is that, we provide quality of the fit to assess reliability of the measurements. The quality assessment can be highly effective for finding new classes of objects. For example, based on the quality assessment around the Ha and [NII] nebular lines, we found approximately 1% of the SDSS spectra which classified as "galaxies" by the SDSS pipeline are in fact type I Seyfert AGN.

• Korean Journal of Environment and Ecology
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• v.20 no.2
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• pp.227-234
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• 2006

The comparison of Corylopsis coreana populations between natural groups and deforestation groups is carried in five regions such as Seungju, Woldeung, Hwangjeon in Suncheon, Myeongseok in Jinju and Mt. Baegun in Pocheon. The number of sprouting per both $100m^2$ and each individual stump were appeared more in deforestation than in natural groups. In contrast, the height and the diameter of individuals by the number of sprouting are higher and larger in the natural groups. The relationship between the floristic composition and vegetation in the two groups of C. coreana populations was not appeared. Corylopsis coreana are propagated sprouting as well as seedling in deforestation groups located an opening area. Because of the powerful environmental adaptability through growth of the sprouting and the seedling in deforestation groups, the population of C. coreana are not extinction of species oneself, and on the contrary are showed expansion of C. coreana population after temporary disturbance.

• ALGAE
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• v.36 no.4
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• pp.231-240
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• 2021

Saccharina sculpera is highly valued for human consumption and value-added products. However, natural resources of this kelp have decreased sharply and it is in danger of extinction. Resources recovery through cultivation is being trialed to enable the sustainable use of this species. In this study, the temperature range for survival and optimal growth of juvenile S. sculpera was identified and applied to field cultivation. This study investigated the survival and growth of juvenile S. sculpera under six temperatures (i.e., 5, 10, 15, 16, 18, and 20℃) and two light intensities (i.e., 20 and 40 µmol photons m^-2 s^-1) in an indoor culture experiment. In these experiments, the blade length decreased at 16℃ under the both light intensities. The thalli died at 20℃ and 20 µmol photons m^-2 s^-1, and at 18-20℃ and 40 µmol photons m^-2 s^-1. During the field cultivation, early growth of S. sculpera was highest at the 5 m depth and growth decreased as the water depth increased. When the initial rearing depth was maintained without adjustment throughout the cultivation period (from December to October), all the cultivated S. sculpera plants died during August and September. However, S. sculpera plants lowered from 5 to 15 m and grew to 90.8 ± 13.1 cm in July. The seawater temperature at 15 m depth was similar to the upper level of thermal tolerance demonstrated by juvenile S. sculpera in the indoor culture experiments (16℃ or lower). The plants were subsequently lowered to 25 m depth in August, which eventually led to their maturation in October. The present study confirmed that improved growth rates and a delay in biomass loss can be achieved by adjusting the depth at which the seaweeds are grown during the cultivation period. These results will contribute to the establishment of sustainable cultivation systems for S. sculpera.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.363-376
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• 2023

As the risk of biodiversity reduction and extinction becomes serious due to climate change and indiscriminate development, the importance of conservation of the natural environment and ecosystem is increasing. In this situation, Ireviewed that overseas cases of the ecological outlook and evaluation system aimed at providing information on natural resources and ecosystem change. As a results, other countries showed that various research institutes have been carrying on field surveys by classification group, but it was different from us that the investigated data are collected and managed in an integrated manner and repeatedly provided within a short period of time. In addition, it was analyzed that it was highly utilized in policy and environmental impact assessment by providing evaluation-based prediction and outlook information along with basic survey data. Based on this, the limitations of information use in our wildlife surveys and environmental impacts assessments were analyzed, and the estabilishment of a ecology outlook and evaluation system and policy support measures were considered. In addition, based on the proposed outlook and evaluation system preparation plan, a policy direction that can be effectively used in domestic natural ecosystem policies was proposed.

• Korean Journal of Plant Taxonomy
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• v.44 no.3
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• pp.165-170
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• 2014

Most evergreen Quercus species are typical, dominant members of Korean evergreen forests. However, little is known about the distribution status of Q. myrsinifolia Blume there. To enhance our knowledge about their natural range in Korea, we conducted field surveys based on specimen records and an extensive literature search. We also determined their exact number as a first step in planning their conservation. The results indicated that these trees are strictly limited to Jin Island, and 169 mature individuals were the maximum number and occurred in only three subpopulations on that island. Previous misidentifications and perhaps mislabeled locations for plant specimens were the main reasons for earlier confusion about distribution. We believe that these results can provide guidance when making specific recommendations for management interventions. These discoveries also demonstrate the value in having reliable information about plant specimens in general. We also speculated about what makes this species particularly vulnerable to local extinction.

• Ecology and Resilient Infrastructure
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• v.3 no.1
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• pp.62-69
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• 2016

Narrow-mouth frog (Kaloula borealis) is the only amphibian species of genus Kaloula living in South Korea. They are designated and managed as endangered class II wildlife by the Ministry of Environment, Korea. Therefore, there is a desperate need of a habitat restoration study to prevent the extinction of narrow-mouth frog. This study is primarily for the purpose of presenting the direction and practical applications to restore damaged narrow-mouth frog habitats or to suggest alternative habitat options. The habitat suitability index (HSI) of narrow-mouth frog was applied to the research area in Mokpo City of Jeollanam-do Province, in order to present a new narrow-mouth frog habitat. We analyzed the research area based on historical contexts, ecological environment, ecology, and habitat requirements. The research area was divided into the core, buffer, and transition zones according to UNESCO MAB (Man and Biosphere) to establish local land-use plans. As for the foundation of the plan, we divided the habitat composition of the core, where narrow-mouth frog live in, into wetland (spawning area), grassland (shelter and feeding grounds), and forestland (feeding ground). We had a comparative analysis of habitat suitability in pre and post planning of narrow-mouth frog habitat restoration. For the validation study of habitat restoration plans, the future research should be on the composition of test-bed, continuous monitoring, and scientific habitat maintenance.

• Korean Journal of Plant Taxonomy
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• v.43 no.3
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• pp.236-243
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• 2013

Many plant species in subalpine regions are under threat of extinction as a result of climate change. In this study, the genetic diversity and geographic differentiation of three regions and six populations of Primula farinosa subsp. modesta (Bisset & Moore) Pax in Korea were assessed using the ISSR (Inter Simple Sequence Repeat) marker. The average genetic diversity (P = 60.62, SI = 0.299, h = 0.190) was relatively lower than that of other long-lived perennials, even though it is a self-incompatible species. AMOVA analysis showed that 50% of the total genetic diversity was partitioned among regions and Bayesian cluster analysis showed some remarkable geographic trends that were structured into 2 or 3 regions, suggesting limited gene flow among regions. Considering the population fragmentation, low level genetic diversity, and high genetic differentiation, it is essential to establish in situ and ex situ conservation strategies for P. farinosa subsp. modesta.