作者机构：
[Yu, ZH] Cent China Normal Univ, Inst Entomol, Wuhan 430070, Peoples R China.;Huazhong Univ Sci & Technol, Tongji Hosp, Ctr Med, Dept Surg,Mol Med Ctr, Wuhan 430079, Peoples R China.;Chinese Acad Sci, Wuhan Inst Virol, Key Lab Mol Virol, Wuhan 430071, Peoples R China.
通讯机构：
[Yu, ZH] C;Cent China Normal Univ, Inst Entomol, Wuhan 430070, Peoples R China.
关键词：
cell cycle;Hz-AM1 cell;Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus;cyclin B-1
摘要：
The cell cycle phase distributions of Hz-AM1 cells grown in monolayer culture were G(1) = 49.7 +/- 3.3%, S = 22.7 +/- 3.8% and G(2)/M = 27.8 +/- 4.2% without >4N DNA content. The culture doubling time was about 40 h and the duration of the G(1), S and G(2)/M phases was estimated to be 10, 14 and 16 h, respectively. HaSNPV infection of Hz-AM1 cells resulted in both unsynchronized and synchronized G, phase arrest at G(2)/M phase. HaSNPV infection also resulted in the appearance of more than 4N DNA content, which accumulated to the highest levels 72 h post-infection. We also found that the expression level of cyclin B I increased significantly after 16 h post-infection, while cyclin A did not show any change. This observation supports the Hz-AM(1)-infected arrest at the G(2)/M phage. Cytoplasm location of cyclin B-1 indicated that the Hz-AM1 cell cycle arrest was at the G(2) phase. (C) 2004 Elsevier B.V. All rights reserved.
作者机构：
[Xiong, L] Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.;Jiangsu Univ, Sch Med Technol, Zhenjiang 212001, Peoples R China.;Chinese Acad Sci, Inst Hydrobiol, Wuhan 430072, Peoples R China.
通讯机构：
[Xiong, L] C;Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.
关键词：
cypermethrin;Daphnia magna HB;toxicity
摘要：
The acute toxic effect of the pesticide cypermethrin to Daphnia magna HB was examined. D. magna HB was exposed to cypermethrin at concentrations of 0, 1, 3, 5, 7, and 9 mg/L for 24 h. Data showed that the 24 h-LC50 of cypermthrin on D. magna HB was 4.81 mg/L. In contrast, the 24 h-LC50 of K2Cr2O7(the national standard toxicant) to Daphnia magna was 0.38 mg/L in the current study. Results indicated that the Daphnia magna was very sensitive to pesticides. In addition, the effects of the culture condition(such as hardness, temperature and DO etc.) on Daphnia magna HB was also studied.
作者机构：
[生秀梅; 谢丽强; 熊丽] College of Life Science, Central China Normal University, Wuhan 430079, China;[夏宜琤; 吴振斌] State Key Lab. Freshw. Ecol./Biotech, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
通讯机构：
[Xiong, L.] C;College of Life Science, , Wuhan 430079, China
作者机构：
[Jen, PHS] Univ Missouri, Div Biol Sci, Columbia, MO 65211 USA.;E China Normal Univ, Dept Biol, Shanghai, Peoples R China.;Cent China Normal Univ, Dept Biol, Wuhan, Peoples R China.
通讯机构：
[Jen, PHS] U;Univ Missouri, Div Biol Sci, Columbia, MO 65211 USA.
摘要：
This electrophysiological study tests the hypothesis that one possible neural pathway for corticofugally inhibited neurons in the central nucleus of the inferior colliculus (ICc) of the big brown bat, Eptesicus fuscus, is mediated through excitatory projections from the auditory cortex (AC) to the external nucleus of the IC (ICx), which then sends inhibitory inputs to the ICc. This study shows that all neurons in the ICx are broadly tuned to stimulus frequency. Electrical stimulation in the AC typically increases the number of impulses, expands the auditory spatial response areas, and broadens the frequency tuning curves (FTCs) of neurons in the ICx. This corticofugal facilitation is mediated at least in part through NMDA receptors, since application of DL-2-amino-5-phosphonovaleric acid (APV), an antagonist for NMDA, decreases these response properties of neurons in the ICx. Electrical stimulation in the ICx typically decreases the number of impulses, reduces the auditory spatial response areas, and narrows the FTCs of neurons in the ICc. This inhibition is mediated at least in part through GABAA receptors, since application of bicuculline, an antagonist for GABA, increases these response properties of neurons in the ICc. These data suggest that corticofugal facilitation of the ICx and the inhibition of the ICx to the ICc may be one of the polysynaptic pathways for corticofugal inhibition of neurons in the ICc. Possible functions of this polysynaptic pathway in acoustic orientation and signal processing are discussed.
作者机构：
[Yang, X] Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.;New Jiang Han Univ, Sch Med, Dept Publ Hlth, Wuhan 430014, Peoples R China.;Wuhan Publ Hlth & antiepidem Stn, Dept Environm Hlth, Wuhan 430022, Peoples R China.
通讯机构：
[Yang, X] C;Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.
关键词：
室内装修;胶合板;室内空气污染物;甲醛;眼部刺激;人体接触控制试验
摘要：
Obejective: The present study focuses on health assessment of wood based panels which are widely used in interior decoration practices over the recent years in China. Formaldehyde has been identified as chemical indicator of (IAO) and an indoor air pollutant. To test its health effects experiment was undertaken. Method: A small environmental test chamber (60/L) was used as the generator of emission gas from new panels, and was operating at a temperature of 22.7 ± 0.6°C and a humidity of 44.4 ± 2.5 % with an air exchange rate of 1.0 ± 0.15h-1. On the three experimental days the values of product loading in chamber were 4, 2 and 6 m2/m3, respectively. Eight people were selected randomly from the students and employees of Wuhan Health and Anti-epidemic Station as subjects, with an average age of 21.9 ± 5.9 years, and a gender ratio of 1:1, and two of them were smokers (one male and one female). The subjects' eyes were exposed to formaldehyde through a pair of goggles. Each goggle had its flow inlet and outlet, and connected to chamber exhaust of emission gas and to an exhaust from the room. The exposure time was very short, just 5 minutes and the formaldehyde doses were at 1.65 ± 0.01, 2.99 ± 0.07 and 4.31 ± 0.02 ppm. A 60-mm linear visual analogue rating scales was used to measure the intensity of sensory eye irritation and a video tape recorder was used to record eye blinking frequency. Results: The results demonstrated that tests of sensory eye irritation and eye blinking can be used for materials testing, and that a dose-effect as well as a time-variance of the effect can be measured. Conclusion: The tests showed that eye irritation was perceived at all of the three levels.
摘要：
The nucleocapsid protein gene (vp39) of a Chinese isolate of Bombyx mori nucleopolyhedrovirus (BmNPV-Ch), namely an open reading frame CORF) of 1050 bp that codes for a polypeptide of 39 K (VP39) consisting of 350 amino acids was sequenced. The homology of the nucleotide (nt) anti am ino acid sequences of vp39 and VP39, respectively, of BmNPV-Ch and a Japanese iso late of BmNPV (BmNPV-Ja) were found to be 97.5% and 97.1%, respectively. The BmNPV-Ch vp39 is nine nucleotides longer than that of BmNPV-Ja vp39 due to insertion of CGA at nt 625 and GTCGGC at nt 985-910. There are differences in 17 nucleotides causing a few substitutions of amino acids which slightly modify the secondary structure of BmNPV-Ch. It indicates that the main part of the secondary structure of VP39 is a Folded structure containing high proportion of beta -sheet and beta -turn units. A clot blot hybridization analysis revealed the existence of a homologous transcript of BmNPV-Ch vp39 in Sm cells infected with Autographa californica multiple nucleocapsid nucleopolyhedrovirus (AcMNPV).
作者机构：
[Luan S.] Department of Plant, University of California, Berkeley, CA 94720, United States;Department of Biology, Central China Normal University, Wuhan 430070, China;[Fu H.-H.] Department of Plant, University of California, Berkeley, CA 94720, United States, Department of Biology, Central China Normal University, Wuhan 430070, China
通讯机构：
[Luan, S.] D;Dept. of Plant and Microbial Biology, University of California, United States
摘要：
Plant roots contain both high- and low-affinity transport systems for uptake of K+ from the soil. In this study, we characterize a K+ transporter that functions in both high- and low-affinity uptake. Using yeast complementation analysis, we isolated a cDNA for a functional K+ transporter from Arabidopsis (referred to as AtKUP1 for Arabidopsis thaliana K+ uptake). When expressed in a yeast mutant, AtKUP1 dramatically increased K+ uptake capacity at both a low and high [K+] range. Kinetic analyses showed that AtKUP1-mediated K+ uptake displays a 'biphasic' pattern similar to that observed in plant roots. The transition from the high-affinity phase (K(m) of 44 μM) to the low-affinity phase (K(m) of 11 mM) occurred at 100 to 200 μM external K+. Both low- and high-affinity K+ uptake via AtKUP1 were inhibited by 5 mM or higher concentrations of NaCl. In addition, AtKUP1-mediated K+ uptake was inhibited by K+ channel blockers, including tetraethylammonium, Cs+, and Ba2+. Consistent with a possible function in K+ uptake from the soil, the AtKUP1 gene is primarily expressed in roots. We conclude that the AtKUP1 gene product may function as a K+ transporter in Arabidopsis roots over a broad range of [K+] in the soil.
期刊：
JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY,1998年183(6):683-697 ISSN：0340-7594
通讯作者：
Jen, P.H.-S.
作者机构：
[P. H.-S. Jen; Q. C. Chen; X. D. Sun] Division of Biological Sciences, University of Missouri-Columbia, Missouri 65211, USA e-mail: pjen@biosci.mbp.missouri.edu Tel.: +1-573-882-7479;Fax: +1-573-884-5020, , US;[P. H.-S. Jen; Q. C. Chen; X. D. Sun] Fax: +1-573-884-5020, , US
通讯机构：
Division of Biological Sciences, University of Missouri, United States
关键词：
Bat;Central auditory sensitivity;Corticofugal facilitation and inhibition;Inferior colliculus
摘要：
Under free-field stimulation conditions, corticofugal regulation of auditory sensitivity of neurons in the central nucleus of the inferior colliculus of the big brown bat, Eptesicus fuscus, was studied by blocking activities of auditory cortical neurons with Lidocaine or by electrical stimulation in auditory cortical neuron recording sites. The corticocollicular pathway regulated the number of impulses, the auditory spatial response areas and the frequency-tuning curves of inferior colliculus neurons through facilitation or inhibition. Corticofugal regulation was most effective at low sound intensity and was dependent upon the time interval between acoustic and electrical stimuli. At optimal inter-stimulus intervals, inferior colliculus neurons had the smallest number of impulses and the longest response latency during corticofugal inhibition. The opposite effects were observed during corticofugal facilitation. Corticofugal inhibitory latency was longer than corticofugal facilitatory latency. Iontophoretic application of gamma-aminobutyric acid and bicuculline to inferior colliculus recording sites produced effects similar to what were observed during corticofugal inhibition and facilitation. We suggest that corticofugal regulation of central auditory sensitivity can provide an animal with a mechanism to regulate acoustic signal processing in the ascending auditory pathway.
摘要：
This study examines the effect of pulse repetition rate (PRR), pulse intensity, and bicuculline on the minimum threshold (MT) and latency of inferior collicular neurons of the big brown bat, Eptesicus fuscus, under free-field stimulation conditions. It tests the hypothesis that changes in MT and latency of collicular neurons are co-dependent on PRR. The number of impulses in inferior collicular neurons (n = 245) increased either monotonically (25%) or non-monotonically (75%) with pulse intensity. Latencies either decreased to a plateau (72%), fluctuated unpredictably within 3 ms (21%) or changed very little (7%) with increasing pulse intensity. Latencies and MTs of most collicular neurons increased by 1.5-24 ms (mean +/- SD = 4.8 +/- 3.3 ms) and 4-75 dB (mean +/- SD = 22.1 +/- 16.2 dB) with increasing PRR. In most neurons (94%), the latency increase was completely (42%) or partially (52%) eliminated when pulse intensity was compensated for the MT increase with PRR. Complete elimination of latency was achieved by bicuculline application. In a few neurons (6%), the latency increase with PRR was not affected by compensated pulse intensity or bicuculline application.
期刊：
JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY,1997年181(6):591-597 ISSN：0340-7594
通讯作者：
Jen, P.H.-S.
作者机构：
[J. X. Shen; Q. C. Chen; P. H.-S. Jen] Division of Biological Sciences, University of Missouri-Columbia, MO 65211, USA Tel.: +1-573-882-7479, Fax.: +1-573-884-5020 e-mail: pjen@biosci.mbp.missouri.edu, , US
通讯机构：
Division of Biological Sciences, University of Missouri, United States
摘要：
This study examines the binaural and frequency representation in the primary auditory cortex (AC) of the big brown bat, Eptesicus fuscus, by using an ear-phone stimulation system. All 306 cortical neurons studied were excited by contralateral sound stimulation but they were either excited, inhibited or not affected by ipsilateral sound stimulation. These cortical neurons were columnarly organized according to their binaural and frequency-tuning properties. The excitation-excitation columns which occupy about 15% of the AC are mainly aggregated within an oval-shaped area of the central AC. The excitation-inhibition neurons and binaural neurons with mixed properties are distributed in the remaining 85% of the surrounding primary AC. Although the best frequency (BF) of these neurons shows a tendency to decrease from high to low along the anteroposterior axis of the primary AC, systematic variation in BF is not always consistent across the entire mapping area. In particular, BFs of cortical neurons isolated in the anterior AC vary quite unsystematically such that neurons with similar BFs are aggregated in isolated patches. Isofrequency and binaural columns are segregated into bands that intersect each other.
作者机构：
[Tomura, D; Shoun, H; Kudo, T; Dai, X Q] Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305, Japan;Department of Biology, Huazhong Normal University, Wuhan, Hubei 430070, China;[Liu, D L] Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305, Japan, Department of Biology, Huazhong Normal University, Wuhan, Hubei 430070, China
通讯机构：
[Shoun, H.] I;Institute of Applied Biochemistry, University of Tsukuba, Japan
摘要：
The cDNAs and genes for two isozymes of cytochrome P450nor of the fungus Cylindrocarpon tonkinense, P450nor1 and P450nor2, were cloned and sequenced. Their deduced amino acid sequences respectively showed 83 and 70% identity to that: of P450nor of Fusarium oxysporum, and 69% identity to each other. The genes for P450nor1 and P450nor2 were termed, respectively, CYP 55A2 and CYP 55A3. The cDNA for P450nor1 contained a targeting-like presequence upstream the N-terminus of mature protein whereas that for P450nor2 did not, suggesting their different intracellular localisations. We also succeeded in expressing these P450nor isoforms in the host-vector system of the yeast Saccharomyces cerevisiae. We purified one of the recombinant proteins, P450nor of F oxysporum. Little difference could be observed between the native and recombinant proteins in catalytic and spectroscopic properties. We constructed chimeric proteins of P450nor of F oxysporum and P450nor2 which are different in their specificity against the electron donors: reduced pyridine nucleotides. The specificity of chimeric proteins against NADH/NADPH showed that the specificity is determined by the N-terminal half of protein. We found a consensus amino acid sequence between three isoforms of P450nor, A-X-G-X-X-A, similar to the NAD-binding motif G-X-G-X-X-G/A in the region that corresponds to the B'-helix in P450cam.
摘要：
Using bats as a model auditory system, we studied corticofugal control of auditory sensitivity of neurons in the inferior colliculus. We demonstrate for the first time that the corticocollicular pathway continuously regulates acoustic signal processing in the inferior colliculus by increasing the threshold, reducing the auditory spatial response area, and sharpening the frequency tuning curve of recorded inferior collicular neurons. Regulation of auditory sensitivity of recorded inferior collicular neurons was observed when the corticocollicular pathway was activated by electrical stimulation in the auditory cortex. The effect of this corticofugal regulation of auditory sensitivity in inferior collicular neurons can also be produced by ionophoretical application of GABA to the collicular recording site. This regulation of ascending acoustic information by commands originating from higher brain centers may provide the bat with a mechanism to actively control acoustic signal processing and thus optimize acoustic signal analysis.
期刊：
JOURNAL OF EXPERIMENTAL BIOLOGY,1995年198(9):2007-2023 ISSN：0022-0949
通讯作者：
Philip H.-S. Jen
作者机构：
UNIV MISSOURI,DIV BIOL SCI,COLUMBIA,MO 65211.;CENT CHINA NORMAL UNIV,DEPT BIOL,WUHAN,PEOPLES R CHINA.;[CHEN, QC] Division of Biological Sciences , University of Missouri-Columbia , MO 65211, USA<&wdkj&>Department of Biology , Central China Normal University , Wuhan, Hubei, People’s Republic of China;[CAIN, D; JEN, PHS] Division of Biological Sciences , University of Missouri-Columbia , MO 65211, USA
通讯机构：
[Philip H.-S. Jen] D;Division of Biological Sciences , University of Missouri-Columbia , MO 65211, USA
摘要：
Sound pressure transformation properties at the pinna of laboratory mice Mus domesticus were studied by measuring the sound pressure level of a continuous tone at a series of frequencies at the tympanic membrane as a function of the position of a sound source under free-field stimulation conditions. The spectral transformation, the interaural spectral difference, the isopressure contours and the interaural pressure difference contours were plotted. Sound pressure transformation functions showed some prominent spectral notches throughout the frequency range tested (10-80 kHz). However, the notch frequency did not appear to be systematically related to sound direction. The study of interaural pressure difference demonstrated that, when delivered from some angles within the ipsilateral frontal hemisphere, the sound pressure at the tympanic membrane of certain frequencies may be lower than that determined at the corresponding contralateral angles. For each sound frequency tested, there was an angle (the acoustic axis) within the ipsilateral frontal hemisphere from which the delivered sound reached a maximal pressure level at the tympanic membrane. However, the acoustic axis often changed to a new angle after removal of the ipsilateral pinna. In addition, sound delivered from the acoustic axis did not always generate a maximal pressure transformation. The isopressure contours determined within 2-5 dB of the maximal pressure were circumscribed, and their contained angular areas were found to decrease with increasing sound frequency. The 2 dB maximal pressure area may appear at more than one angular area for some test frequencies. Removal of the ipsilateral pinna or modification of pinna posture expanded isopressure contours irregularly and split the 2 dB maximal pressure area into several parts. The sound pressure difference determined between the angles of maximal and minimal sound pressure (the maximal directionality) increased with sound frequency regardless of pinna posture. Acoustic gain of the pinna at the acoustic axis reached 6-12 dB, depending upon sound frequency. However, the pinna gain was not always maximal at the acoustic axis for a given frequency.
作者机构：
UNIV MISSOURI, DIV BIOL SCI, COLUMBIA, MO 65211 USA.;CENT CHINA NORMAL UNIV, DEPT BIOL, WUHAN, PEOPLES R CHINA.;[CHEN, QC; JEN, PHS] Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO 65211, United States
通讯机构：
[Jen, P.H.-S.] D;Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO 65211, United States
