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In JoVE (1)
Other Publications (9)
- Nephrology, Dialysis, Transplantation : Official Publication of the European Dialysis and Transplant Association - European Renal Association
- The International Journal of Biochemistry & Cell Biology
- IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
- Nature
- Science in China. Series C, Life Sciences / Chinese Academy of Sciences
- Yao Xue Xue Bao = Acta Pharmaceutica Sinica
- Mechanisms of Ageing and Development
- Tree Physiology
- Plant Physiology
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Articles by Qiang Qiu in JoVE
JoVE Neuroscience
Responses imagem Neuronal em Preparações Slice of Organ Vomeronasal Expressando um sensor de cálcio geneticamente codificado
1Stowers Institute for Medical Research, 2Department of Anatomy and Cell Biology, The University of Kansas School of Medicine
Other articles by Qiang Qiu on PubMed
Effects of Co-administration of Urokinase and Benazepril on Severe IgA Nephropathy
The availability of treatment for IgA nephropathy (IgAN) is limited. Method. A prospective randomized controlled clinical trial was performed to evaluate the effects of therapy with urokinase (UK) and benazepril (BZ, an angiotensin-converting enzyme inhibitor) or BZ alone on severe IgAN. We divided 71 cases of IgAN, Lee's grade >/=III and with fibrinogen deposits, into two groups to be treated for 12 months with either UK + BZ or BZ alone.
Interactions of C-reactive Protein with Low-density Lipoproteins: Implications for an Active Role of Modified C-reactive Protein in Atherosclerosis
The interaction of C-reactive protein with low-density lipoprotein is considered to be one of the key properties that link C-reactive protein with atherosclerosis. However the data obtained to date are controversial, and hence make it difficult to conclude actual physiological or pathological impact of such interaction. The incompatible findings could be ascribed to the different structural state of C-reactive protein and/or low-density lipoprotein. We investigated in detail the interaction of various C-reactive protein isoforms with native and modified low-density lipoprotein. Our data showed "C-reactive protein" could indeed interact with each of native low-density lipoprotein, oxidized or enzymatically modified low-density lipoprotein, but that interaction occurs primarily when C-reactive protein is conformed in a modified form and not pentameric structure. Low level of modified C-reactive protein "contaminant" could confer C-reactive protein obvious low-density lipoprotein binding capacity. Interaction of modified C-reactive protein and low-density lipoprotein was mediated synergistically by both electrostatic association with ApoB and hydrophobic insertion into lipid layer. When complexed with modified C-reactive protein, macrophage binding/uptake of native and oxidized low-density lipoprotein was either increased 150% or decreased 35%, respectively. Thus the interaction of modified C-reactive protein with low-density lipoprotein may contribute to the regulation of low-density lipoprotein metabolism and foam cell formation in arterial wall. These results highlight an active role of modified C-reactive protein in atherosclerotic process.
Evaluation of an Algorithm for Semiautomated Segmentation of Thin Tissue Layers in High-frequency Ultrasound Images
An algorithm consisting of speckle reduction by median filtering, contrast enhancement using top- and bottom-hat morphological filters, and segmentation with a discrete dynamic contour (DDC) model was implemented for nondestructive measurements of soft tissue layer thickness. Algorithm performance was evaluated by segmenting simulated images of three-layer phantoms and high-frequency (40 MHz) ultrasound images of porcine aortic valve cusps in vitro. The simulations demonstrated the necessity of the median and morphological filtering steps and enabled testing of user-specified parameters of the morphological filters and DDC model. In the experiments, six cusps were imaged in coronary perfusion solution (CPS) then in distilled water to test the algorithm's sensitivity to changes in the dimensions of thin tissue layers. Significant increases in the thickness of the fibrosa, spongiosa, and ventricularis layers, by 53.5% (p < 0.001), 88.5% (p < 0.001), and 35.1% (p = 0.033), respectively, were observed when the specimens were submerged in water. The intraobserver coefficient of variation of repeated thickness estimates ranged from 0.044 for the fibrosa in water to 0.164 for the spongiosa in CPS. Segmentation accuracy and variability depended on the thickness and contrast of the layers, but the modest variability provides confidence in the thickness measurements.
Ultrasonic Communication in Frogs
Among vertebrates, only microchiropteran bats, cetaceans and some rodents are known to produce and detect ultrasounds (frequencies greater than 20 kHz) for the purpose of communication and/or echolocation, suggesting that this capacity might be restricted to mammals. Amphibians, reptiles and most birds generally have limited hearing capacity, with the ability to detect and produce sounds below approximately 12 kHz. Here we report evidence of ultrasonic communication in an amphibian, the concave-eared torrent frog (Amolops tormotus) from Huangshan Hot Springs, China. Males of A. tormotus produce diverse bird-like melodic calls with pronounced frequency modulations that often contain spectral energy in the ultrasonic range. To determine whether A. tormotus communicates using ultrasound to avoid masking by the wideband background noise of local fast-flowing streams, or whether the ultrasound is simply a by-product of the sound-production mechanism, we conducted acoustic playback experiments in the frogs' natural habitat. We found that the audible as well as the ultrasonic components of an A. tormotus call can evoke male vocal responses. Electrophysiological recordings from the auditory midbrain confirmed the ultrasonic hearing capacity of these frogs and that of a sympatric species facing similar environmental constraints. This extraordinary upward extension into the ultrasonic range of both the harmonic content of the advertisement calls and the frog's hearing sensitivity is likely to have co-evolved in response to the intense, predominantly low-frequency ambient noise from local streams. Because amphibians are a distinct evolutionary lineage from microchiropterans and cetaceans (which have evolved ultrasonic hearing to minimize congestion in the frequency bands used for sound communication and to increase hunting efficacy in darkness), ultrasonic perception in these animals represents a new example of independent evolution.
Latency Represents Sound Frequency in Mouse IC
Frequency is one of the fundamental parameters of sound. The frequency of an acoustic stimulus can be represented by a neural response such as spike rate, and/or first spike latency (FSL) of a given neuron. The spike rates/frequency function of most neurons changes with different acoustic amplitudes, whereas FSL/frequency function is highly stable. This implies that FSL might represent the frequency of a sound stimulus more efficiently than spike rate. This study involved representations of acoustic frequency by spike rate and FSL of central inferior colliculus (IC) neurons responding to free-field pure-tone stimuli. We found that the FSLs of neurons responding to characteristic frequency (CF) of sound stimulus were usually the shortest, regardless of sound intensity, and that spike rates of most neurons showed a variety of function according to sound frequency, especially at high intensities. These results strongly suggest that FSL of auditory IC neurons can represent sound frequency more precisely than spike rate.
[Effect of Lidamycin on Mitochondria Initiated Apoptotic Pathway in Human Cancer Cells]
Although enediyne antibiotic lidamycin ( LDM) is a potent inducer of apoptosis, the underlying mechanisms of its apoptotic functions remain to be explored. Here, we aim to elucidate its possible mechanisms in mitochondria initiated apoptotic pathway involved in human BEL-7402 and MCF-7 cells. Cytochrome c released from mitchondria to cytosol fraction was detected by Western blotting. p53 and Bax, Bcl-2 expressions were detected by Western blotting and RT-PCR. MTT assay was used to detect cytotoxicity of LDM with or without caspase inhibitor z-VAD-fmk. After the BEL-7402 cells were exposed to 0. 1 micromol x L(-1) LDM within 6 h, the increase of cytochrome c in the cytosol and decrease in the mitochondria were observed when compared with untreated cells. The expression of Bax, an important proapoptotic member of the Bcl-2 family, increased gradually in the BEL-7402 cells after exposure to LDM of 0. 1 micromol x L (-1) for 2, 6, and 9 h, separately, while Bcl-2 increased at 2 and 6 h, and decreased at 9 h after LDM treatment. Enhanced protein expressions were parallel with respective increased mRNA level for Bax only, but not p53. Caspase inhibitor may inhibit partially the killing effects induced by LDM. Therefore we conclude that the rapid activation of mitochondrial pathway induced by LDM in tumor cells might contribute to its highly potent cytotoxicities.
Salidroside Protects Human Fibroblast Cells from Premature Senescence Induced by H(2)O(2) Partly Through Modulating Oxidative Status
Although salidroside and salidroside-like compounds are considered as most critical constitutes needed and responsible for multiple therapeutic benefits of Rhodiola rosea L., including anti-aging, direct demonstration regarding the role of salidroside in anti-aging process is still deficient. In this study, we selected the H(2)O(2)-induced premature senescence model in human fetal lung diploid fibroblasts to investigate the protection of salidroside against aging in vitro and associated molecular mechanisms. We found that salidroside considerably reversed senescence-like phenotypes in the oxidant challenged model, including alterations of morphology, cell cycle, SA-β-gal staining, DNA damage, as well as related molecules expression such as p53, p21 and p16. The protection occurred in a dose-dependent manner, with 5μM offering best efficacy. The proposed antioxidant property of the compound was confirmed in this cellular system, and thus at least partially accounted for the protection of the compound against premature senescence. Similar protection of salidroside against replicative senescence was observed as well. Interestingly, the regulation of senescence-related molecules by salidroside involved ROS-irrelevant mechanisms in both models. This finding presents salidroside as an attractive agent with potential to retard aging and attenuate age-related diseases in humans.
Genome-scale Transcriptome Analysis of the Desert Poplar, Populus Euphratica
Populus euphratica is well-adapted to extreme desert environments and is an important model species for studying the effects of abiotic stresses on trees. Here we present the first deep transcriptomic analysis of this species. To maximize representation of conditional transcripts, mRNA was obtained from living tissues of desert-grown trees and two types of callus (salt-stressed and unstressed). De novo assembly generated 86,777 Unigenes using Solexa sequence data. These sequences covered 92% of previously reported P. euphratica expressed sequence tags (ESTs) and 90% of the TIGR poplar ESTs, and a total of 58,499 high-quality unique sequences were annotated by BLAST similarity searches against public databases. We found that 27% of the total Unigenes were differentially expressed (up- or down-regulated) in response to salt stress in P. euphratica callus. These differentially expressed genes are mainly involved in transport, transcription, cellular communication and metabolism. In addition, we found that numerous putative genes involved in ABA regulation and biosynthesis were also differentially regulated. This study represents the deepest transcriptomic and gene-annotation analysis of P. euphratica to date. The genetic knowledge acquired should be very useful for future studies of the molecular adaptation of this tree species to abiotic stress and facilitate genetic manipulation of other poplar species.
HCF243 Encodes a Chloroplast-localized Protein Involved in the D1 Protein Stability of the Arabidopsis Photosystem II Complex
Numerous auxiliary nuclear factors have been identified to be involved in the dynamics of the photosystem II (PSII) complex. In this study, we characterized the high chlorophyll fluorescence243 (hcf243) mutant of Arabidopsis (Arabidopsis thaliana), which shows higher chlorophyll fluorescence and is severely deficient in the accumulation of PSII supercomplexes compared with the wild type. The amount of core subunits was greatly decreased, while the outer antenna subunits and other subunits were hardly affected in hcf243. In vivo protein-labeling experiments indicated that the synthesis rate of both D1 and D2 proteins decreased severely in hcf243, whereas no change was found in the rate of other plastid-encoded proteins. Furthermore, the degradation rate of the PSII core subunit D1 protein is higher in hcf243 than in the wild type, and the assembly of PSII is retarded significantly in the hcf243 mutant. HCF243, a nuclear gene, encodes a chloroplast protein that interacts with the D1 protein. HCF243 homologs were identified in angiosperms with one or two copies but were not found in lower plants and prokaryotes. These results suggest that HCF243, which arose after the origin of the higher plants, may act as a cofactor to maintain the stability of D1 protein and to promote the subsequent assembly of the PSII complex.
