• Microbiology and Biotechnology Letters
• /
• v.42 no.2
• /
• pp.131-138
• /
• 2014

While coupling wastewater treatment with microalgal bioenergy production is very promising, new approaches are needed to enhance microalgal growth and lipid accumulation in wastewater. Therefore, this study investigated the effect of iron on the growth, nutrient removal, and lipid accumulation of Scenedesmus sp. LX1 in both artificial wastewater and domestic secondary effluents. When increasing the iron concentration from 0 to 2 mg/l in the artificial wastewater, the biomass production of Scenedesmus sp. LX1 increased from 0.17 to 0.54 g/l; the nitrogen and phosphorus removal efficiency increased from 15.7% and 80.6% to 97.0% and 99.2%, respectively; and the lipid content was enhanced 84.2%. The relationship between the carrying capacity/maximal population growth rate of Scenedesmus sp. LX1 and the initial iron concentration were also in accordance with the Monod model. Furthermore, when increasing the iron concentration to 2 mg/l in four different domestic secondary effluent samples, the lipid content and lipid production of Scenedesmus sp. LX1 was improved by 17.4-33.7% and 21.5-41.8%, respectively.

• Genomics & Informatics
• /
• v.21 no.3
• /
• pp.35.1-35.12
• /
• 2023

The Bacillus cereus group, also known as B. cereus sensu lato (B. cereus s.l.), is composed of various Bacillus species, some of which can cause diarrheal or emetic food poisoning. Several emerging highly heat-resistant Bacillus species have been identified, these include B. thermoamylovorans, B. sporothermodurans, and B. cytotoxicus NVH 391-98. Herein, we performed whole genome analysis of two thermotolerant Bacillus sp. isolates, Bacillus sp. B48 and Bacillus sp. B140, from an omelet with acacia leaves and fried rice, respectively. Phylogenomic analysis suggested that Bacillus sp. B48 and Bacillus sp. B140 are closely related to B. cereus and B. thuringiensis, respectively. Whole genome alignment of Bacillus sp. B48, Bacillus sp. B140, mesophilic strain B. cereus ATCC14579, and thermophilic strain B. cytotoxicus NVH 391-98 using the Mauve program revealed the presence of numerous homologous regions including genes responsible for heat shock in the dnaK gene cluster. However, the presence of a DUF4253 domain-containing protein was observed only in the genome of B. cereus ATCC14579 while the intracellular protease PfpI family was present only in the chromosome of B. cytotoxicus NVH 391-98. In addition, prophage Clp protease-like proteins were found in the genomes of both Bacillus sp. B48 and Bacillus sp. B140 but not in the genome of B. cereus ATCC14579. The genomic profiles of Bacillus sp. isolates were identified by using whole genome analysis especially those relating to heat-responsive gene clusters. The findings presented in this study lay the foundations for subsequent studies to reveal further insights into the molecular mechanisms of Bacillus species in terms of heat resistance mechanisms.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.18 no.2
• /
• pp.83-89
• /
• 2009

Multiplication and spore production of three microsporidia(Nosema bombycis, Nosema sp. 1 and Nosema sp. 2) in selected tissues of pupa and adult of silkworm, Bombyx mori L. were studied in two seasons (SI, SII) with distinct temperature (SI: $20.1{\pm}0.8^{\circ}C$ and SII: $25.1{\pm}0.7^{\circ}C$) regimes. Multiplication of the microsporidia followed a logistic pattern with a lag phase, an exponential phase and a stationary phase. In SII, spore production was significantly (P<0.01) higher in various tissues. Highest spore production was observed 30 days post inoculation (p.i.) in SI and in SII, it was $21{\sim}23$ days p.i. Spore production was significantly (P<0.01) higher in the gut tissues than other tissues. Nosema sp. 2 registered significantly (P<0.01) higher spore production in both the seasons compared to Nosema bombycis and Nosema sp. 1. Results indicate that the multiplication and spore production of microsporidia are tissue specific and extremely sensitive to the temperature at which the host is reared. Through this study, the precise day that the spore numbers of the microsporidia are maximized can be predicted in both pupa and adult in case the infection is initiated in the first instar.

• Animal Systematics, Evolution and Diversity
• /
• v.21 no.1
• /
• pp.111-122
• /
• 2005

A study on marine sponges was conducted by SCUBA diving at Ulleungdo Island and Gageodo Island, Korea during the period from July 2000 to October 2001. Two species, Clathria (Clathria) gombawuiensis n. sp. and Clathria (C) gageoensis n. sp., are new to the fauna of sponges. Clathria (C) gombawuiensis n. sp. closely relates to Clathria (C) conica Levi, 1963 based on the type of spicules, but differs in size of spicules and growth form, Clathria (C) conica has not small toxa. Clathria (C) gageoensis n. sp. is similar to Clathria (C) hexagonopora Levi, 1963, but it differs in size of spicules and growth form, also Clathria (C) hexagonopora has not small toxa.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2020.12a
• /
• pp.16-44
• /
• 2020

Cancer is the second leading cause of death in the world. According to the 2018 reports, one in six people worldwide is reported to die as a result of cancer. The discovery of anticancer drugs has been utilized extensively, but there has been no report on excellent selective activity in cancer cells. The discovery of bioactive substances from marine sponges has been the limelight in the pharmaceutical field over the past decade owing to the production of many bioactive compounds from the sponges to protect themselves against the environment. On top of that, marine sponges also produced cytotoxic compounds such as terpenoids, alkaloids, steroids, and peptides which suggests that marine sponges have high potential in the development of anticancer drugs. Thus, this study aimed to obtain new cytotoxic compounds from S. siphonella in Egypt and Arenoscelra sp. and Gelliodes sp. in Vietnam, and further investigation of the extract from these marine sponges led to isolation of ten new compounds and 21 known compounds. Chapter 1 will discuss about the isolation and structure elucidation of eight new polyacetylene derivatives from S. siphonella and their cytotoxic activities. The isolation and structural elucidation of one new polybrominated iododiphenyl ether from Arenosoclea sp. as well as cytotoxic activities of the isolated compounds will be reported in chapter 2. Finally, isolation and structure elucidation of new compounds from the marine sponge Gelliodes sp. and their cytotoxic activities will be discussed in chapter 3.

• Journal of Dairy Science and Biotechnology
• /
• v.41 no.3
• /
• pp.103-112
• /
• 2023

This study aimed to assess the effectiveness of 10 different pre-enrichment methods using Real-Time polymerase chain reaction (PCR) in support of the FDA method. When the initial Cronobacter spp. (Enterobacter sakazakii) inoculation was 7.2 CFU/g, the Ct values were observed in the following order: 21.37 (Enterobacteriaceae enrichment [EE] broth), 21.95 (brain heart infusion [BHI]), 22.72 (tryptic soy broth [TSB]), 23.02 (violet red bile lactose [VRBL]), 22.31 (TSB-0.1% sodium pyruvate [SP]), 23.43 (distilled water [DW]), 24.34 (phosphate buffered saline [PBS]), 24.95 (nutrient broth [NB]), 25.82 (TSB-0.6% yeast extract [YE]), and 28.27 (violet red bile glucose [VRBG]). For an inoculation of 1.82% CFU/g of Cronobacter spp. (E. sakazakii), the Ct values were recorded in this sequence: 20.34 (EE broth), 22.16 (TSB-0.6% YE), 22.37 (BHI), 22.71 (VRBL), 22.88 (TSB), 23.01 (DW), 23.19 (NB), 23.79 (TSB-0.1% SP), 24.66 (VRBG), and 24.70 (PBS). Finally, when the inoculum of Cronobacter spp. (E. sakazakii) was 0.182 CFU/g, the Ct values followed this order: 21.93 (VRBL), 23.07 (TSB-0.6% YE), 23.31 (DW), 23.47 (PBS), 23.70 (BHI), 24.14 (TSB-0.1% SP), 25.14 (TSB), 29.00 (VRBG), 31.55 (EE broth), and were undetected in the case of NB. Consequently, these results indicate that there were no significant differences among the 10 different pre-enrichment broths. Future studies should focus on exploring pre-enrichment broths that can improve the limit of detection at very low Cronobacter spp. (E. sakazakii) concentrations and enhance the selective recovery of Cronobacter spp. (E. sakazakii) under acid, antibiotic, cold, and heat damage conditions.

• Information Display
• /
• v.13 no.1
• /
• pp.21-30
• /
• 2012

• Proceedings of the Zoological Society Korea Conference
• /
• 1995.10b
• /
• pp.159.1-159
• /
• 1995

No Abstract, See Full Text

• Journal of the Korean Magnetics Society
• /
• v.10 no.1
• /
• pp.16-21
• /
• 2000

Magnetic properties and crystallographic properties of $Cu_{0.95}Ge_{0.95}Fe_{0.1}O_3$ were studied by using x-ray diffraction, superconducting quantum interference device (SQUID) and Mossbauer spectroscopy. Our sample has orthorhombic structure and the lattice constants are a = 4.795 $\AA$, b = 8.472 $\AA$, c = 2.932 $\AA$. The spin-Peierls (SP) transition temperatures of our sample is 13 K. The Mossbauer spectra consisted with two Zeeman sextets and one doublet due to $Fe^{3+}$ions. The Zeeman sextets come from tetrahedral $Fe^{3+}$ions and the doublets come from octahedral $Fe^{3+}$ions. The jump up of magnetic hyperfine field of 2nd Zeeman sextet and the increasing of the values of quadrupole splitting and isomer shift of doublet below SP transition temperature could be interpreted related with the atomic displacements. The N el temperature is 715 K, the Debye temperature are 540 K for octahedral site and 380 K for tetrahedral site, respectively.

• Korean Journal of Food Science and Technology
• /
• v.20 no.5
• /
• pp.724-731
• /
• 1988

For a study on the production of ${\gamma}-linolenic$ acid(GLA) by microorganisms, fifteen strains of Mucorales obtained from culture stocks and ten isolate strains were compared in their cell growth, lipid content, fatty acid composition and pellet size formed in shake flask culture. Among the fungi examined, the isolated fungus, designated as FB-354, was found to be the most suitable one for the production of GLA mainly due to its high contents of lipid, 29.9% of dry cell weight and GLA, 16.8% of the total fatty acids. The strain FB-354 was tentatively identified as Mucor sp. on the basis of morphological characteristics. Fungal oil produced by Mucor sp. FB-354 was fractionated into 81.1% of neutral lipid, 7.2% of glycolipid, and 11.8% of phospholipid. Although the GLA content in the phospholipid fraction was as high as 21.4%, most of the GLA was found in the neutral lipid fraction.