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31.
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Antiserum to leucokinin I, a neuropeptide originally isolated from the cockroach Leucophaea maderae, was used for immunocytochemical labeling of neurons in the brain and ventral ganglia of the moth Spodoptera litura during postembryonic development. In the ventral ganglia, leucokinin-like immunoreactivity begins to occur in the abdominal ganglion A3 to A7 of first instar larva. One to two weakly labeled pairs of bilateral LK-LI cell bodies are located in the subesophageal ganglion of fourth to sixth instar larvae and in the abdominal ganglia A1 to A7 of second to sixth instar larvae. The abdominal ganglion A1 of fourth to sixth instar larvae and A8 of sixth instar larva each contain one weakly labeled pair of median LK-LI cell bodies. Two strongly labeled pairs of bilateral LK-LI neurons are found in A3 to A7 of third to sixth instar larvae. Abdominal ganglia A1 to A8 of prepupa, pupa and adult contain one to three weakly labeled pairs of bilateral LK-LI neurons. Two strongly labeled pairs of bilateral LK-LI neurons in each of the abdominal ganglia of larva, prepupa, pupa and adult send axons to the neuropil, and then each axon bifurcates into two axonal branches. Theses axonal branches from two bundles. From each of the two pairs of neurons an axon exits through the posterior ventral nerve (N2) which runs to the transverse nerve of the next posterior segment. In larval brains, 2-16 pairs of bilateral LK-LI cell bodies can be found together with LK-LI processes in the central neuropil. The larval brains show large changes in the number of LK-LI neurons throughout postembryonic development. The number of LK-LI cell bodies are reduced in number from sixth instar larval brain. Therefore, prepupal, pupal and adult brains contain a smaller number of LK-LI cell bodies. Two pairs of LK-LI median neurosecretory cells located immediately beside the pars intercerebralis in larval brains increase to three pairs in the 7-day-old pupal brain. In the adult, however, LK-LI median neurosecretory cells decrease to one pair. 相似文献
33.
TC Hsu Y Zhao RY Wang R Dickerson JC Liang X Wang Y Wu 《Canadian Metallurgical Quarterly》1998,12(3):617-620
In a breast cancer cell line, MDA-MB-468, established in our laboratory, an average of 3% of the mitotic cells exhibited a phenomenon known as centromere splaying, which is a characteristic feature of cells of patients with Roberts syndrome. However, centromere splaying in cells of Roberts syndrome patients is limited to i) the centromere region and ii) chromosomes with large amounts of heterochromatin. When the breast cancer cells were treated with an extract of green tea GTE-TP91, up to 45% of the metaphases were observed to exhibit this behavior; and the precocious centromere separation was highly exaggerated, affecting all chromosomes in such metaphases. Apparently, as the sister centromeres continued to pull apart, they carried the chromatids with them, except for the telomere regions, giving a ring-like configuration. Eventually, the sister chromatids became completely separated. Whether this bizarre phenomenon was induced by the polyphenols contained in this green tea extract GTE-TP91 is not known, but this phenomenon, upon further investigation, may throw some light on chromosomal proteins, centromere behavior, telomere behavior and related questions. 相似文献
34.
RY Litovsky 《Canadian Metallurgical Quarterly》1997,102(3):1739-1745
The precedence effect refers to an auditory phenomenon which occurs when two similar sounds are presented from different locations with a brief delay, and only one sound is heard whose perceived location is dominated by the first source. Although the lagging source si not localized as an independent event, under some conditions, adults are able to extract its directional cues. Developmental studies suggest that this ability changes during the development. However, those studies have used stimulus configurations which minimize the measurement of that ability. In the present study adults were first tested under several conditions, and the one which produced optimal performance was chosen for testing children. Using the minimum audible angle (MAA) task in the azimuthal plane, performance was compared for a single-source condition and two precedence conditions: in lag discrimination the lagging source changed location while the lead remained at midline, and in lead discrimination the reverse occurred. Subjects were 18 months old, 5 years old, and adult. Significant improvements in MAA occurred with an increase in age, especially in the precedence conditions. Within each group, performance was significantly better in single-source condition, followed by the lead and the lag discrimination. 相似文献
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Nitric oxide acts directly in the presynaptic neuron to produce long-term potentiation in cultured hippocampal neurons 总被引:1,自引:0,他引:1
O Arancio M Kiebler CJ Lee V Lev-Ram RY Tsien ER Kandel RD Hawkins 《Canadian Metallurgical Quarterly》1996,87(6):1025-1035
Nitric oxide (NO) has been proposed to act as a retrograde messenger during long-term potentiation (LTP) in the CA1 region of hippocampus, but the inaccessibility of the presynaptic terminal has prevented a definitive test of this hypothesis. Because both sides of the synapse are accessible in cultured hippocampal neurons, we have used this preparation to investigate the role of NO. We examined LTP following intra- or extracellular application of an NO scavenger, an inhibitor of NO synthase, and a membrane-impermeant NO donor that releases NO only upon photolysis with UV light. Our results indicate that NO is produced in the postsynaptic neuron, travels through the extracellular space, and acts directly in the presynaptic neuron to produce long-term potentiation, supporting the hypothesis that NO acts as a retrograde messenger during LTP. 相似文献
38.
Factors affecting their developmental quotients (DQ) in 48 normal young children, who were involved in regular development assessments at child health care outpatient visits and whose parents received child-rearing guidance at Chaoyangmen Subdistrict of Dongcheng District, Beijing, and 43 controls aged 36 months were analyzed. Factors, such as their parents' receiving child-rearing guidance, paternal education, maternal education, paternal occupation, type of nursery schools, home environment quality score (HEQS) at 24 and 36 months of age, and mothers' knowledge of child-rearing were associated with children's DQ at their age of 36 months, with statistical significance at a level of 0.05 in univariate analysis. With multiple regression analysis, HEQS at the age of 36 months, family size at the age of 24 months, paternal education, children's sex, and mothers' age had influences on DQ at age of 36 months with statistical significance, and the degree of correlation of HEQS with DQ at 36 months was much higher than that of other factors, and it suggested that HEQS was an important link in child developmental intervention. 相似文献
39.
Studies were conducted on harvesting of Bacillus thuringiensis (Bt)-based biopesticides from fermented broths of starch industry wastewater (SIW), wastewater sludge (raw and hydrolyzed-NH and TH, respectively) and semi-synthetic soyameal to enhance entomotoxicity (Tx) by centrifugation. Pertinent factors influencing Tx, solids concentration, pH, temperature and centrifugal force were investigated. The centrifugate solids concentration beyond 100 g/l did not enhance Tx, instead caused pellet formation. Centrifugation efficiency (Tx recovery) was higher at pH 4, and temperature 20 degrees C for starch wastewater (98%), wastewater sludge (98% and 97.8% for non-hydrolyzed and hydrolyzed, respectively) and soya broth (83%). For maximum Tx recovery (SIW-95%; NH-90%; TH-98% and soya-78%), the centrifugal force and time required was 48,000 g and 30 min, respectively. Losses in recovery efficiency were lower for SIW and wastewater sludge in comparison to soya on adopting commercially recommended centrifugal force of 9000 g. The settling velocity computations for different fermented broths enabled calculation of Sigma factor for continuous commercial centrifuge of a given capacity and hence simulation of power requirements. It was established that power requirements for a given Tx recovery efficiency were highest for conventional medium (soya) in comparison to other waste-based fermented broths. 相似文献
40.
In this study, the application of response surface model in predicting and optimizing the ferro-sonication pre-treatment for degradation of bisphenol A (BPA), an endocrine disrupter compound from wastewater sludge (WWS) was investigated. The ferro-sonication pre-treatment process was carried out according to central composite design (CCD) with four independent variables such as wastewater sludge solids concentration, pH, ultrasonication time and FeSO(4) concentration. The effect of ferro-sonication pre-treatment was assessed in terms of increase in sludge solids (suspended solids (SS) and volatile solids (VS)) and organic matter (chemical oxygen demand (COD) and soluble organic carbon (SOC)) solubilization and simultaneous BPA degradation from WWS. It was observed that among all the variables studied, ultrasonication time had more significantly affected the efficiency of the ferro-sonication pre-treatment process followed by FeSO(4) and solids concentration. Through this optimization process, it was found that maximum BPA degradation of 88% could be obtained with 163 min ultrasonication time, 2.71 mg/L FeSO(4) concentration, pH 2.81 with 22 g/L SS. Further, the effect of ferro-sonication pre-treatment on biodegradation of WWS was also studied. It was observed that ultrasonication time had significant effect and the higher biodegradation (32.48%) was observed at 180 min ultrasonication time. 相似文献