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91.
Sau-chi B. Yan Sutaeg Hwang Timothy D. Rustan William H. Frey 《Neurochemical research》1985,10(1):1-18
The soluble tubulin of human cerebral cortex, as assessed by [3H]colchicine binding of the 100,000g supernatant fraction, decreases drastically with age, 75 percent from age 0 to age 90. There is also a considerably lower concentration of high molecular weight proteins in the soluble fraction of postmortem human cerebral cortex than in that of nonhuman species. Human brain tubulin can be polymerized into microtubules with DEAE-dextran. The DEAE-dextran induced microtubules are stable to cold temperature (4°) and calcium. However, in the presence of 1 M glutamate, the microtubules become cold labile and depolymerize at 4°. Thus we have developed a novel method for purifying polymerization competent tubulin from fresh or frozen human cerebral cortex. Human brain tubulin purified by our novel method is very similar to tubulin from the brains of other mammals in molecular weight, amino acid composition, polymerization-depolymerization parameters, and structural dimensions of the microtubules formed.Some aspects of this work have been published as an abstract in 1981. Fed. Proc. 40:1548. 相似文献
92.
Assassin bugs are one of the most successful clades of predatory animals based on their species numbers (∼6,800 spp.) and wide distribution in terrestrial ecosystems. Various novel prey capture strategies and remarkable prey specializations contribute to their appeal as a model to study evolutionary pathways involved in predation. Here, we reconstruct the most comprehensive reduviid phylogeny (178 taxa, 18 subfamilies) to date based on molecular data (5 markers). This phylogeny tests current hypotheses on reduviid relationships emphasizing the polyphyletic Reduviinae and the blood-feeding, disease-vectoring Triatominae, and allows us, for the first time in assassin bugs, to reconstruct ancestral states of prey associations and microhabitats. Using a fossil-calibrated molecular tree, we estimated divergence times for key events in the evolutionary history of Reduviidae. Our results indicate that the polyphyletic Reduviinae fall into 11–14 separate clades. Triatominae are paraphyletic with respect to the reduviine genus Opisthacidius in the maximum likelihood analyses; this result is in contrast to prior hypotheses that found Triatominae to be monophyletic or polyphyletic and may be due to the more comprehensive taxon and character sampling in this study. The evolution of blood-feeding may thus have occurred once or twice independently among predatory assassin bugs. All prey specialists evolved from generalist ancestors, with multiple evolutionary origins of termite and ant specializations. A bark-associated life style on tree trunks is ancestral for most of the lineages of Higher Reduviidae; living on foliage has evolved at least six times independently. Reduviidae originated in the Middle Jurassic (178 Ma), but significant lineage diversification only began in the Late Cretaceous (97 Ma). The integration of molecular phylogenetics with fossil and life history data as presented in this paper provides insights into the evolutionary history of reduviids and clears the way for in-depth evolutionary hypothesis testing in one of the most speciose clades of predators. 相似文献
93.
Hyemin Choi Jae-Sam Hwang Ho Kim Dong Gun Lee 《Biochemical and biophysical research communications》2013
In our previous study, coprisin, a 43-mer defensin-like peptide, was derived from the dung beetle, Copris tripartitus, and a 9-mer CopA3 (monomer), truncated coprisin analog peptide, was designed. However, the antifungal effects of CopA3 are not known yet. In this study, the antifungal activity and mechanism of CopA3 were investigated and to develop a more effective antimicrobial peptide under physiological conditions, the enantiomeric d-CopA3 was designed. l- and d-CopA3 had a similar antifungal activity without chiral selectivity, and their activity was more potent than that of melittin used as a positive control. Furthermore, l- and d-CopA3 did not even show any hemolysis against human erythrocytes. Membrane studies using propidium iodide and bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)], suggested that the antifungal effect of l- and d-CopA3 was due to the membrane-active mechanism, by contrast with coprisin possessing apoptotic mechanism without membrane permeabilization. Finally, the proteolytic resistance and antifungal activity of l- and d-CopA3 against trypsin was analyzed by HPLC and colony count assay. The results showed that only d-CopA3 maintained a potent antifungal activity despite the proteolytic condition. Therefore, this study suggests that d-CopA3 has potential as a novel antimicrobial agent. 相似文献
94.
K Seki M Murai J Sakurada A Shirahige N Kobayashi S M Hwang S Masuda 《Microbiology and immunology》1989,33(1):81-85
A simple method was developed to visually present the phagocytic activity of leukocytes by using adherent Staphylococcus aureus cells and blood applied on a plastic dish. When heparinized blood was applied on thin-layer of heat-killed S. aureus cells on the plastic dish, plaques due to the phagocytic activity of leukocytes were observed with a microscope under a low magnification. Fewer and smaller plaques were observed when plasma-deprived rather than whole blood was used. Some analyses were made in respect to the fundamental conditions required for optimal results. This method was considered to be useful for conveniently evaluating the serum opsonin activities and phagocytic function of leukocytes in various kinds of diseases. 相似文献
95.
Sung‐Je Moon Jae‐Hoon Kim Young‐Keun Choi Chul‐Ho Lee Jung Hwan Hwang 《Journal of cellular and molecular medicine》2020,24(15):8814-8825
The growth arrest and DNA damage‐inducible beta (Gadd45β) protein have been associated with various cellular functions, but its role in progressive renal disease is currently unknown. Here, we examined the effect of Gadd45β deletion on cell proliferation and apoptosis, inflammation, and renal fibrosis in an early chronic kidney disease (CKD) mouse model following unilateral ureteral obstruction (UUO). Wild‐type (WT) and Gadd45β‐knockout (KO) mice underwent either a sham operation or UUO and the kidneys were sampled eight days later. A histological assay revealed that ablation of Gadd45β ameliorated UUO‐induced renal injury. Cell proliferation was higher in Gadd45β KO mouse kidneys, but apoptosis was similar in both genotypes after UUO. Expression of pro‐inflammatory cytokines after UUO was down‐regulated in the kidneys from Gadd45β KO mice, whereas UUO‐mediated immune cell infiltration remained unchanged. The expression of pro‐inflammatory cytokines in response to LPS stimulation decreased in bone marrow‐derived macrophages from Gadd45β KO mice compared with that in WT mice. Importantly, UUO‐induced renal fibrosis was ameliorated in Gadd45β KO mice unlike in WT mice. Gadd45β was involved in TGF‐β signalling pathway regulation in kidney fibroblasts. Our findings demonstrate that Gadd45β plays a crucial role in renal injury and may be a therapeutic target for the treatment of CKD. 相似文献
96.
Jung‐Gu Han Chihyun Hwang Su Hwan Kim Chanhyun Park Jonghak Kim Gwan Yeong Jung Kyungeun Baek Sujong Chae Seok Ju Kang Jaephil Cho Sang Kyu Kwak Hyun‐Kon Song Nam‐Soon Choi 《Liver Transplantation》2020,10(20)
High‐capacity Li‐rich layered oxide cathodes along with Si‐incorporated graphite anodes have high reversible capacity, outperforming the electrode materials used in existing commercial products. Hence, they are potential candidates for the development of high‐energy‐density lithium‐ion batteries (LIBs). However, structural degradation induced by loss of interfacial stability is a roadblock to their practical use. Here, the use of malonic acid‐decorated fullerene (MA‐C60) with superoxide dismutase activity and water scavenging capability as an electrolyte additive to overcome the structural instability of high‐capacity electrodes that hampers the battery quality is reported. Deactivation of PF5 by water scavenging leads to the long‐term stability of the interfacial structures of electrodes. Moreover, an MA‐C60‐added electrolyte deactivates the reactive oxygen species and constructs an electrochemically robust cathode‐electrolyte interface for Li‐rich cathodes. This work paves the way for new possibilities in the design of electrolyte additives by eliminating undesirable reactive substances and tuning the interfacial structures of high‐capacity electrodes in LIBs. 相似文献
97.
Gihoon Cha Shiva Mohajernia Nhat Truong Nguyen Anca Mazare Nikita Denisov Imgon Hwang Patrik Schmuki 《Liver Transplantation》2020,10(6)
Recently, sodium ion batteries (SIBs) have been widely investigated as one of the most promising candidates for replacing lithium ion batteries (LIBs). For SIBs or LIBs, designing a stable and uniform solid electrolyte interphase (SEI) at the electrode–electrolyte interface is the key factor to provide high capacity, long‐term cycling, and high‐rate performance. In this paper, it is described how a remarkably enhanced SEI layer can be obtained on TiO2 nanotube (TiO2 NTs) arrays that allows for a strongly improved performance of sodium battery systems. Key is that a Li+ pre‐insertion in TiO2 NTs can condition the SEI for Na+ replacement. SIBs constructed with Li‐pre‐inserted NTs deliver an exceptional Na+ cycling stability (e.g., 99.9 ± 0.1% capacity retention during 250 cycles at a current rate of 50 mA g?1) and an excellent rate capability (e.g., 132 mA h g?1 at a current rate of 1 A g?1). The key factor in this outstanding performance is that Li‐pre‐insertion into TiO2 NTs leads not only to an enhanced electronic conductivity in the tubes, but also expands the anatase lattice for facilitated subsequent Na+ cycling. 相似文献
98.
Jeong Ho Hwang Eunjoong Kim Eun Young Choi Jong Bong Choi Jong Kyun Park 《Entomological Research》2020,50(5):221-228
Gonggeom‐ji pond is the first protected paddy field wetland area, designated by the Ministry of Environment of Korea in 2011, because of its high biodiversity and historic value. It contains reservoirs, paddy fields, and a forest site that provides diverse niches for insects. Quantitative methods were used in this study to estimate the insect diversity of this region. A transect of 50 m was designated in each site (reservoirs, paddy fields, and a forest site). Data were collected using sweeping and pitfall traps along each transect in May, August, and November 2017, representative of the seasons—spring, summer, and autumn, respectively. As a result, a total of 1079 individual insects representing 170 species from 60 families within nine orders were collected. Diversity, richness, and evenness indices were the highest in the forest site in May (4.77, 8.6, and 0.91, respectively). The dominance index was the highest in the forest site in November (0.64). Similarity index was the highest in the reservoir in May and August (0.519). These results would help compare different sites and their vegetation to assess relationships between insects and habitats. 相似文献
99.
Acetylation changes tau interactome to degrade tau in Alzheimer’s disease animal and organoid models
Heesun Choi Haeng Jun Kim Jinhee Yang Sehyun Chae Wonik Lee Sunwoo Chung Jisoo Kim Hyunjung Choi Hyeseung Song Chang Kon Lee Jae Hyun Jun Yong Jae Lee Kyunghyeon Lee Semi Kim Hye‐ri Sim Young Il Choi Keun Ho Ryu Jong‐Chan Park Dongjoon Lee Sun‐Ho Han Daehee Hwang Jangbeen Kyung Inhee Mook‐Jung 《Aging cell》2020,19(1)
Alzheimer's disease (AD) is an age‐related neurodegenerative disease. The most common pathological hallmarks are amyloid plaques and neurofibrillary tangles in the brain. In the brains of patients with AD, pathological tau is abnormally accumulated causing neuronal loss, synaptic dysfunction, and cognitive decline. We found a histone deacetylase 6 (HDAC6) inhibitor, CKD‐504, changed the tau interactome dramatically to degrade pathological tau not only in AD animal model (ADLPAPT) brains containing both amyloid plaques and neurofibrillary tangles but also in AD patient‐derived brain organoids. Acetylated tau recruited chaperone proteins such as Hsp40, Hsp70, and Hsp110, and this complex bound to novel tau E3 ligases including UBE2O and RNF14. This complex degraded pathological tau through proteasomal pathway. We also identified the responsible acetylation sites on tau. These dramatic tau‐interactome changes may result in tau degradation, leading to the recovery of synaptic pathology and cognitive decline in the ADLPAPT mice. 相似文献
100.
Jisub Hwang Chang-Sook Jeong Chang Woo Lee Seung Chul Shin Han-Woo Kim Sung Gu Lee Ui Joung Youn Chang Sup Lee Tae-Jin Oh Hak Jun Kim Hyun Park Hyun Ho Park Jun Hyuck Lee 《Journal of microbiology (Seoul, Korea)》2020,58(7):606-613
Crystal structures of enoyl-coenzyme A (CoA) isomerase from Bosea sp. PAMC 26642 (BoECI) and enoyl-CoA hydratase from Hymenobacter sp. PAMC 26628 (HyECH) were determined at 2.35 and 2.70 Å resolution, respectively. BoECI and HyECH are members of the crotonase superfamily and are enzymes known to be involved in fatty acid degradation. Structurally, these enzymes are highly similar except for the orientation of their C-terminal helix domain. Analytical ultracentrifugation was performed to determine the oligomerization states of BoECI and HyECH revealing they exist as trimers in solution. However, their putative ligand-binding sites and active site residue compositions are dissimilar. Comparative sequence and structural analysis revealed that the active site of BoECI had one glutamate residue (Glu135), this site is occupied by an aspartate in some ECIs, and the active sites of HyECH had two highly conserved glutamate residues (Glu118 and Glu138). Moreover, HyECH possesses a salt bridge interaction between Glu98 and Arg152 near the active site. This interaction may allow the catalytic Glu118 residue to have a specific conformation for the ECH enzyme reaction. This salt bridge interaction is highly conserved in known bacterial ECH structures and ECI enzymes do not have this type of interaction. Collectively, our comparative sequential and structural studies have provided useful information to distinguish and classify two similar bacterial crotonase superfamily enzymes. 相似文献