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Search Results: 1 - 10 of 249721 matches for " Sheng-Ping L. Hwang "
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Zebrafish Agr2 Is Required for Terminal Differentiation of Intestinal Goblet Cells
Yi-Chung Chen, Yu-Fen Lu, I-Chen Li, Sheng-Ping L. Hwang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034408
Abstract: Background Mammalian Anterior Gradient 2 (AGR2) is a protein disulfide isomerase that is required for the production of intestinal mucus and Paneth and goblet cell homeostasis. However, whether increased endoplasmic reticulum (ER) stress occurs in Agr2?/? mice remains a controversial issue. Methodology/Principal Findings We characterized the function of zebrafish agr2 by both morpholino antisense oligomer-mediated knockdown and agr2 mRNA overexpression. Fluorescent whole-mount double in situ hybridization indicated that in the intestine, agr2 was only expressed in goblet cells. Significantly increased numbers of immature Alcian blue-stained goblet cells were observed in the intestines of 104- and 120-hours post fertilization (hpf) agr2 morphants. Transmission electron microscopy analyses further confirmed the existence of immature pre-goblet cells containing few mucous granules in the mid-intestines of 104- and 120-hpf agr2 morphants. agr2 expression was not significantly induced by an ER stress inducer, tunicamycin. Expression of the ER chaperone gene hspa5, the spliced form of xbp1s, c/enhancer binding protein homologous protein chop, and the activating transcription factor 4b1 atf4b1 were not significantly induced in either 104-hpf agr2 morphants or agr2-overexpressed embryos. Similar percentages of P-Histone H3-stained M phase cells were identified in intestines of 104-hpf agr2 morphants and control embryos. Conclusions/Significance Our study demonstrates that in contrast to mouse AGR2, zebrafish Agr2 is expressed in only one intestinal secretory cell type - the goblet cells. Agr2 is essential for terminal differentiation of intestinal goblet cells in zebrafish embryos. Either knockdown of agr2 function or agr2 overexpression could not extensively induce expression of members of the unfolded protein response pathway.
Congestive feedback uniformly partitions red blood cells in the zebrafish microvasculature
Shyr-Shea Chang,Shenyinying Tu,Yu-Hsiu Liu,Van Savage,Sheng-Ping L. Hwang,Marcus Roper
Quantitative Biology , 2015,
Abstract: Vascular networks are widely thought to be organized to traffic oxygen and dissolved chemicals to tissues as efficiently as possible. Yet the kinetics of oxygen disassociation require that red blood cells travel through each capillary at approximately the same rate, and it is not known how vascular networks realize uniform flow across fine vessels distributed at different distances from the heart. Here we study the trunk vessels of developing zebrafish embryos as a model for red blood cell partitioning in real vascular systems. Experimental measurements in a live zebrafish embryo show that fluxes are highly uniform between different vessels. Red blood cells partially clog the vessels that they flow through, so there is congestive feedback between the number of cells in a vessel and the flux into that vessel. Precisely controlling the congestive feedback creates uniform flow across distant segmental vessels. Although eliminating congestion is a key element in the design of efficient transport networks, this work suggests that microvasculature networks may target uniformity, rather than efficiency, and that they do so by creating and controlling congestion.
Zona Pellucida Domain-Containing Protein β-Tectorin is Crucial for Zebrafish Proper Inner Ear Development
Chung-Hsiang Yang, Chia-Hsiung Cheng, Gen-Der Chen, Wei-Hao Liao, Yi-Chung Chen, Kai-Yun Huang, Pung-Pung Hwang, Sheng-Ping L. Hwang, Chang-Jen Huang
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023078
Abstract: Background The zona pellucida (ZP) domain is part of many extracellular proteins with diverse functions from structural components to receptors. The mammalian β-tectorin is a protein of 336 amino acid residues containing a single ZP domain and a putative signal peptide at the N-terminus of the protein. It is 1 component of a gel-like structure called the tectorial membrane which is involved in transforming sound waves into neuronal signals and is important for normal auditory function. β-Tectorin is specifically expressed in the mammalian and avian inner ear. Methodology/Principal Findings We identified and cloned the gene encoding zebrafish β-tectorin. Through whole-mount in situ hybridization, we demonstrated that β-tectorin messenger RNA was expressed in the otic placode and specialized sensory patch of the inner ear during zebrafish embryonic stages. Morpholino knockdown of zebrafish β-tectorin affected the position and number of otoliths in the ears of morphants. Finally, swimming behaviors of β-tectorin morphants were abnormal since the development of the inner ear was compromised. Conclusions/Significance Our results reveal that zebrafish β-tectorin is specifically expressed in the zebrafish inner ear, and is important for regulating the development of the zebrafish inner ear. Lack of zebrafish β-tectorin caused severe defects in inner ear formation of otoliths and function.
Zebrafish Krüppel-Like Factor 4a Represses Intestinal Cell Proliferation and Promotes Differentiation of Intestinal Cell Lineages
I-Chen Li,Chein-Tso Chan,Yu-Fen Lu,Yi-Ting Wu,Yi-Chung Chen,Guo-Bin Li,Che-Yi Lin,Sheng-Ping L. Hwang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0020974
Abstract: Mouse krüppel-like factor 4 (Klf4) is a zinc finger-containing transcription factor required for terminal differentiation of goblet cells in the colon. However, studies using either Klf4?/? mice or mice with conditionally deleted Klf4 in their gastric epithelia showed different results in the role of Klf4 in epithelial cell proliferation. We used zebrafish as a model organism to gain further understanding of the role of Klf4 in the intestinal cell proliferation and differentiation.
β-Lapachone induces heart morphogenetic and functional defects by promoting the death of erythrocytes and the endocardium in zebrafish embryos
Yi-Ting Wu, Che Yi Lin, Ming-Yuan Tsai, Yi-Hua Chen, Yu-Fen Lu, Chang-Jen Huang, Chao-Min Cheng, Sheng-Ping L Hwang
Journal of Biomedical Science , 2011, DOI: 10.1186/1423-0127-18-70
Abstract: Embryos were treated with β-lapachone or dimethyl sulfoxide (DMSO) at 24 or 48 hours post fertilization (hpf) for 4 h at 28°C. Heart looping and valve development was analyzed by whole-mount in situ hybridization and histological analysis. For fractional shortening and wall shear stress analyses, AB and Tg (gata1:DsRed) embryos were recorded for their heart pumping and blood cell circulations via time-lapse fluorescence microscopy. Dextran rhodamine dye injection into the tail reticular cells was used to analyze circulation. Reactive oxygen species (ROS) was analyzed by incubating embryos in 5-(and 6-)-chloromethyl-2',7'-dichloro-dihydrofluorescein diacetate (CM-H2DCFDA) and recorded using fluorescence microscopy. o-Dianisidine (ODA) staining and whole mount in situ hybridization were used to analyze erythrocytes. TUNEL assay was used to examine DNA fragmentation.We observed a linear arrangement of the ventricle and atrium, bradycardia arrhythmia, reduced fractional shortening, circulation with a few or no erythrocytes, and pericardial edema in β-lapachone-treated 52-hpf embryos. Abnormal expression patterns of cmlc2, nppa, BMP4, versican, and nfatc1, and histological analyses showed defects in heart-looping and valve development of β-lapachone-treated embryos. ROS production was observed in erythrocytes and DNA fragmentation was detected in both erythrocytes and endocardium of β-lapachone-treated embryos. Reduction in wall shear stress was uncovered in β-lapachone-treated embryos. Co-treatment with the NQO1 inhibitor, dicoumarol, or the calcium chelator, BAPTA-AM, rescued the erythrocyte-deficiency in circulation and heart-looping defect phenotypes in β-lapachone-treated embryos. These results suggest that the induction of apoptosis of endocardium and erythrocytes by β-lapachone is mediated through an NQO1- and calcium-dependent pathway.The novel finding of this study is that β-lapachone affects heart morphogenesis and function through the induction of apoptosis of
Low Temperature Mitigates Cardia Bifida in Zebrafish Embryos
Che-Yi Lin, Cheng-Chen Huang, Wen-Der Wang, Chung-Der Hsiao, Ching-Feng Cheng, Yi-Ting Wu, Yu-Fen Lu, Sheng-Ping L. Hwang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069788
Abstract: The coordinated migration of bilateral cardiomyocytes and the formation of the cardiac cone are essential for heart tube formation. We investigated gene regulatory mechanisms involved in myocardial migration, and regulation of the timing of cardiac cone formation in zebrafish embryos. Through screening of zebrafish treated with ethylnitrosourea, we isolated a mutant with a hypomorphic allele of mil (s1pr2)/edg5, called s1pr2as10 (as10). Mutant embryos with this allele expressed less mil/edg5 mRNA and exhibited cardia bifida prior to 28 hours post-fertilization. Although the bilateral hearts of the mutants gradually fused together, the resulting formation of two atria and one tightly-packed ventricle failed to support normal blood circulation. Interestingly, cardia bifida of s1pr2as10 embryos could be rescued and normal circulation could be restored by incubating the embryos at low temperature (22.5°C). Rescue was also observed in gata5 and bon cardia bifida morphants raised at 22.5°C. The use of DNA microarrays, digital gene expression analyses, loss-of-function, as well as mRNA and protein rescue experiments, revealed that low temperature mitigates cardia bifida by regulating the expression of genes encoding components of the extracellular matrix (fibronectin 1, tenascin-c, tenascin-w). Furthermore, the addition of N-acetyl cysteine (NAC), a reactive oxygen species (ROS) scavenger, significantly decreased the effect of low temperature on mitigating cardia bifida in s1pr2as10 embryos. Our study reveals that temperature coordinates the development of the heart tube and somitogenesis, and that extracellular matrix genes (fibronectin 1, tenascin-c and tenascin-w) are involved.
Zebrafish Adar2 Edits the Q/R Site of AMPA Receptor Subunit gria2α Transcript to Ensure Normal Development of Nervous System and Cranial Neural Crest Cells
I-Chen Li, Yu-Chia Chen, Yi-Yun Wang, Bo-Wei Tzeng, Chun-Wen Ou, Yi-Yan Lau, Kan-Mai Wu, Tzu-Min Chan, Wei-Hsiang Lin, Sheng-Ping L. Hwang, Wei-Yuan Chow
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0097133
Abstract: Background Adar2 deaminates selective adenosines to inosines (A-to-I RNA editing) in the double-stranded region of nuclear transcripts. Although the functions of mouse Adar2 and its biologically most important substrate gria2, encoding the GluA2 subunit of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptor, have been extensively studied, the substrates and functions of zebrafish Adar2 remain elusive. Methods/Principal Findings Expression of Adar2 was perturbed in the adar2 morphant (adar2MO), generated by antisense morpholio oligonucleotides. The Q/R editing of gria2α was reduced in the adar2MO and was enhanced by overexpression of Adar2, demonstrating an evolutionarily conserved activity between zebrafish and mammalian Adar2 in editing the Q/R site of gria2. To delineate the role of Q/R editing of gria2α in the developmental defects observed in the adar2MO, the Q/R editing of gria2α was specifically perturbed in the gria2αQRMO, generated by a morpholio oligonucleotide complementary to the exon complementary sequence (ECS) required for the Q/R editing. Analogous to the adar2-deficient and Q/R-editing deficient mice displaying identical neurological defects, the gria2αQRMO and adar2MO displayed identical developmental defects in the nervous system and cranial cartilages. Knockdown p53 abolished apoptosis and partially suppressed the loss of spinal cord motor neurons in these morphants. However, reducing p53 activity neither replenished the brain neuronal populations nor rescued the developmental defects. The expressions of crestin and sox9b in the neural crest cells were reduced in the adar2MO and gria2αQRMO. Overexpressing the edited GluA2αR in the adar2MO restored normal expressions of cresting and sox9b. Moreover, overexpressing the unedited GluA2αQ in the wild type embryos resulted in reduction of crestin and sox9b expressions. These results argue that an elevated GluA2αQ level is sufficient for generating the cranial neural crest defects observed in the adar2MO. Our results present a link between dysfunction of AMPA receptors and defective development of the nervous system and cranial neural crest in the zebrafish.
Twin-VCM Controller Design for the Nutator System with Evolutionary Algorithms
Hsieh Sheng-Ping,Hwang Thong-Shing,Ni Chih-Wen
IETE Technical Review , 2009,
Abstract: We present an evolutionary algorithm to optimize controller parameters for a nonlinear nutator system which is implemented in twin voice coil motors (VCMs). In this paper, genetics-based algorithm is applied to tune the proportional-integral-derivative (PID) controller for the multi-input multi-output (MIMO) coupling system. The result has been validated that this algorithm can find out all six PID control parameters in optimal and robust senses. The controller architecture of the nutator system is constructed to meet the specifications of the coupled mirror and rocker parallel loops, both adopting PID control. Two main linear VCMs operating in a push-pull organization drive the nutator subreflector. The mandatory operation mode for the nutator system is two-position switching. The required technical specifications for the nutator control system are extremely precise requirements, system tracking control with a disturbance force more challenging than that in ordinary systems. Simulation results have demonstrated the superiority of the evolutionary algorithm, satisfying the Atacama large -millimeter/submillimeter array (ALMA) severe conditions and requirements.
High Degree Diophantine Equation c^q=a^p+b^p
Sheng-Ping Wu
Mathematics , 2008,
Abstract: The main idea of this article is simply calculating integer functions in module, such as Modulated Function and digital function. The algebraic in the integer modules is studied in completely new style. By difference analysis in module and a careful constructing, a condition of non-solution of Diophantine Equation $a^p+b^p=c^q$ is proved that: $a,b>0,(a,b)=(b,c)=1,p,q>10$, $p$ is prime. The proof of this result is mainly in the last two sections.
Isothermal reduction kinetics of Panzhihua ilmenite concentrate under 30vol% CO–70vol% N2 atmosphere
Ying-yi Zhang,Wei Lü,Xue-wei Lü,Sheng-ping Li,Chen-guang Bai,Bing Song,Ke-xi Han
- , 2017, DOI: https://doi.org/10.1007/s12613-017-1401-x
Abstract: The reduction of ilmenite concentrate in 30vol% CO–70vol% N2 atmosphere was characterized by thermogravimetric and differential thermogravimetric (TG–DTG) analysis methods at temperatures from 1073 to 1223 K. The isothermal reduction results show that the reduction process comprised two stages; the corresponding apparent activation energy was obtained by the iso-conversional and model-fitting methods. For the first stage, the effect of temperature on the conversion degree was not obvious, the phase boundary chemical reaction was the controlling step, with an apparent activation energy of 15.55–40.71 kJ·mol–1. For the second stage, when the temperatures was greater than 1123 K, the reaction rate and the conversion degree increased sharply with increasing temperature, and random nucleation and subsequent growth were the controlling steps, with an apparent activation energy ranging from 182.33 to 195.95 kJ·mol–1. For the whole reduction process, the average activation energy and pre-exponential factor were 98.94–118.33 kJ·mol–1 and 1.820–1.816 min–1, respectively.
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