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81.
82.
ABSTRACTThis paper presents an active learning approach that focuses on practical investigation of the ecosystem of tidal flats using 3D modeling and printing for biology students in order to enhance understanding of natural selection. The learning approach for the study followed a 5-step procedure: i) learning about 3D modeling and printing, ii) exploration of the ecosystem of tidal flats, iii) 3D designing of a bird beak, iv) 3D printing of a constructed beak, and v) a natural selection simulation activity. The learning method presented in this study centered on active student exploration of the tidal flats ecosystem using 3D modeling and printing. The learning approach presented in this paper could be implicated at schools to aid in students’ understanding of natural selection as it allows students to firsthand examine simulation changes to a bird beak and benthic communities. This study suggested the active learning method for natural selection as it incorporates student-designed exploration and direct investigative appraisal of the selection process. 相似文献
83.
Jennifer Jooyoun Kim Ji Hyung Kim Young-Kyung Kwon Kae Kyoung Kwon Sung-Hyun Yang Jiyi Jang Soo-Jin Heo Heung-Sik Park Won-Kyo Jung Youngdeuk Lee Do-Hyung Kang Chulhong Oh 《Current microbiology》2013,67(6):742-747
An aerobic, Gram-negative, coccoid to short rod-shaped and non-flagellated marine bacterial strain S354T was isolated from seawater of Micronesia. The strain was capable to degrade agar-forming slight depression into agar plate. Growth occurred at a temperature range of 12–44 °C, a pH range of 5–9, and a salinity range of 1–7 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences suggested that S354T belongs to the family Flammeovirgaceae. The novel strain was most closely related to Limibacter armeniacum YM 11-185T with similarity of 92.5 %. The DNA G+C content was 43.8 mol%. The major fatty acids (>10 %) were iso-C15:0 and C16:1 ω5c. The predominant isoprenoid quinone was determined to be MK-7. Polar lipid profile of S354T consisted of phosphatidylethanolamine, unknown polar lipid, and unknown glycolipids. Based on the phenotypic, phylogenetic, biochemical, and physiological tests conducted in this study, S354T is proposed to represent a type strain of a novel genus and species. The 16S rRNA gene sequence of S354T is registered in GenBank under the accession number JQ639084. The type of strain Algivirga pacifica gen. nov., sp. nov. is S354T (=KCCM 90107T=JCM 18326T). 相似文献
84.
Pitna Kim Jin Hee Park Chang Soon Choi Inah Choi So Hyun Joo Min Kyoung Kim Soo Young Kim Ki Chan Kim Seung Hwa Park Kyoung Ja Kwon Jongmin Lee Seol-Heui Han Jong Hoon Ryu Jae Hoon Cheong Jung Yeol Han Ki Narm Ko Chan Young Shin 《Neurochemical research》2013,38(3):620-631
Prenatal exposure to alcohol has consistently been associated with adverse effects on neurodevelopment, which is collectively called fetal alcohol spectrum disorder (FASD). Increasing evidence suggest that prenatal exposure to alcohol increases the risk of developing attention deficit/hyperactivity disorder-like behavior in human. In this study, we investigated the behavioral effects of prenatal exposure to EtOH in offspring mice and rats focusing on hyperactivity and impulsivity. We also examined changes in dopamine transporter and MeCP2 expression, which may underlie as a key neurobiological and epigenetic determinant in FASD and hyperactive, inattentive and impulsive behaviors. Mouse or rat offspring born from dam exposed to alcohol during pregnancy (EtOH group) showed hyper locomotive activity, attention deficit and impulsivity. EtOH group also showed increased dopamine transporter and norepinephrine transporter level compared to control group in the prefrontal cortex and striatum. Prenatal exposure to EtOH also significantly decreased the expression of MeCP2 in both prefrontal cortex and striatum. These results suggest that prenatal exposure to EtOH induces hyperactive, inattentive and impulsive behaviors in rodent offspring that might be related to global epigenetic changes as well as aberration in catecholamine neurotransmitter transporter system. 相似文献
85.
Previously, we isolated and characterized attacin from Spodoptera exigua and a coleoptericin-like protein from Protaetia brevitarsis seulensis. In this study, we fused these two genes encoding antimicrobial proteins to obtain a hybrid protein with enhanced antimicrobial activity. To fuse the two antimicrobial proteins, we employed helical and non-helical linker sequences that function as inter-domain linkers in proteins. We used the Gly–Gly–Gly–Gly–Ser peptide as a non-helical linker. The hybrid protein produced using this linker showed less antimicrobial activity against Escherichia coli, Bacillus subtilis, Burkholderia glumae, Pseudomonas corrugate, and Erwinia rhapontici than either of the two parental antimicrobial proteins. In addition, the MIC value of the hybrid protein was 23.1 μM, which indicates poor activity against E. coli. When we used three Glu–Ala–Ala–Ala–Lys (EAAAK) peptide sequences as a helical linker to fuse the two proteins, the resultant hybrid protein had much higher antimicrobial activity than the parental antimicrobial proteins. In particular, this hybrid protein had strong antimicrobial activity against P. corrugate. These results indicate that the EAAAK motif can be used to effectively separate two antimicrobial proteins and produce a hybrid protein with more antimicrobial activity than either of the parent proteins. 相似文献
86.
Jeong Won Kang Young Gyu Choi Jun Ha Lee Oh Kuen Kwon Ho Jung Hwang 《Molecular simulation》2013,39(9):829-835
Pure carbon nanotube (CNT) oscillators are compared to the corresponding CNT oscillators encapsulating copper nanowires (Cu@CNTs) by molecular dynamics simulations. The classical oscillation theory provides a fairly good estimate of the mass dependence of the operating frequency when the CNT surface is not deformed by the Cu nanowire. The structural deformations of the CNT induced by the encapsulated copper nanowire have a greater effect on the oscillation frequency than the mass of the copper nanowire. The excess forces of the Cu@CNT oscillator are slightly higher than those of the CNT oscillator and the excess van der Waals forces induced by the inter-wall interactions are 17 times higher than the excess forces induced by the Cu nanowire–CNT interactions. 相似文献
87.
Hye Jung Lee Sailila E. Abdula Dae Won Jang Sung-Han Park Ung-Han Yoon Yu Jin Jung Kwon Kyoo Kang Ill Sup Nou Yong-Gu Cho 《Plant cell reports》2013,32(10):1521-1529
Key message
Overexpression of OsGS gene modulates oxidative stress response in rice after exposure to cadmium stress. Our results describe the features of transformants with enhanced tolerance to Cd and abiotic stresses.Abstract
Glutamine synthetase (GS) (EC 6.3.1.2) is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine. Exposure of plants to cadmium (Cd) has been reported to decrease GS activity in maize, pea, bean, and rice. To better understand the function of the GS gene under Cd stress in rice, we constructed a recombinant pART vector carrying the GS gene under the control of the CaMV 35S promoter and OCS terminator and transformed using Agrobacterium tumefaciens. We then investigated GS overexpressing rice lines at the physiological and molecular levels under Cd toxicity and abiotic stress conditions. We observed a decrease in GS enzyme activity and mRNA expression among transgenic and wild-type plants subjected to Cd stress. The decrease, however, was significantly lower in the wild type than in the transgenic plants. This was further validated by the high GS mRNA expression and enzyme activity in most of the transgenic lines. Moreover, after 10 days of exposure to Cd stress, increase in the glutamine reductase activity and low or no malondialdehyde contents were observed. These results showed that overexpression of the GS gene in rice modulated the expression of enzymes responsible for membrane peroxidation that may result in plant death. 相似文献88.
Key message
Arabidopsis gulliver3 - D/dwarf4 - D displays growth-promoting phenotypes due to activation tagging of a key brassinosteroid biosynthetic gene DWARF4. In gul3-D/dwf4-D , the Jasmonate and Salicylate signaling pathways were relatively activated and suppressed, respectively.Abstract
Energy allocation between growth and defense is elegantly balanced to achieve optimal development in plants. Brassinosteroids (BRs), steroidal hormones essential for plant growth, are regulated by other plant hormones, including auxin and jasmonates (JA); auxin stimulates the expression of a key brassinosteroid (BR) biosynthetic gene, DWARF4 (DWF4), whereas JA represses it. To better understand the interaction mechanisms between growth and defense, we isolated a fast-growing mutant, gulliver3-D (gul3-D), that resulted from the activation tagging of DWF4, and examined the response of this mutant to defense signals, including JA, Pseudomonas syringae pv. tomato (Pst DC3000) infection, and wounding. The degree of root growth inhibition following MeJA treatment was significantly decreased in gul3-1D/dwf4-5D relative to the wild type, suggesting that JA signaling is partially desensitized in gul3-1D. Quantitative RT-PCR analysis of the genes involved in JA and salicylic acid (SA) responses, including MYC2, PDF1.2, CORI3, PR1, and PR2, revealed that JA signaling was preferentially activated in gul3-1D, whereas SA signaling was suppressed. As a result, gul3-1D was more susceptible to a biotrophic pathogen, Pst DC3000. Based on our results, we propose a model in which BR and JA cooperate to balance energy allocation between growth and defense responses. In ambient conditions, BRs promote plant growth; however, when stresses trigger JA signaling, JA compromises BR signaling by downregulating DWF4 expression. 相似文献89.
Philippe Noriel Q. Pascua Min-Suk Song Hyeok-Il Kwon Gyo-Jin Lim Eun-Ha Kim Su-Jin Park Ok-Jun Lee Chul-Joong Kim Richard J. Webby Robert G. Webster Young-Ki Choi 《Journal of virology》2013,87(19):10552-10562
We previously reported that influenza A/swine/Korea/1204/2009(H1N2) virus was virulent and transmissible in ferrets in which the respiratory-droplet-transmissible virus (CT-Sw/1204) had acquired simultaneous hemagglutinin (HAD225G) and neuraminidase (NAS315N) mutations. Incorporating these mutations into the nonpathogenic A/swine/Korea/1130/2009(H1N2, Sw/1130) virus consequently altered pathogenicity and growth in animal models but could not establish efficient transmission or noticeable disease. We therefore exploited various reassortants of these two viruses to better understand and identify other viral factors responsible for pathogenicity, transmissibility, or both. We found that possession of the CT-Sw/1204 tripartite viral polymerase enhanced replicative ability and pathogenicity in mice more significantly than did expression of individual polymerase subunit proteins. In ferrets, homologous expression of viral RNA polymerase complex genes in the context of the mutant Sw/1130 carrying the HA225G and NA315N modifications induced optimal replication in the upper nasal and lower respiratory tracts and also promoted efficient aerosol transmission to respiratory droplet contact ferrets. These data show that the synergistic function of the tripartite polymerase gene complex of CT-Sw/1204 is critically important for virulence and transmission independent of the surface glycoproteins. Sequence comparison results reveal putative differences that are likely to be responsible for variation in disease. Our findings may help elucidate previously undefined viral factors that could expand the host range and disease severity induced by triple-reassortant swine viruses, including the A(H1N1)pdm09 virus, and therefore further justify the ongoing development of novel antiviral drugs targeting the viral polymerase complex subunits. 相似文献