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M Hessing R A Vlooswijk T M Hackeng D Kanters B N Bouma 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(1):204-208
C4b-binding protein (C4BP) is a multimeric plasma protein, which regulates the classical pathway of the C system. C4BP interacts with C C4b on a domain located in a 48-kDa chymotryptic fragment. We now demonstrate that C4BP contains heparin-binding fragments, which are located within the C4b binding domain. We have used an assay using heparin coupled to Sepharose CL-6B to show that 125I-C4BP binds to heparin in a time-dependent, saturable, and reversible manner. Binding could be inhibited by purified 48-kDa fragments and direct binding on the 48-kDa fragments to heparin-Sepharose was demonstrated by SDS-PAGE. mAb against native C4BP and the isolated 160-kDa central core fragment were evaluated for their ability to block the binding of 125I-C4BP to heparin and C4b. The relative efficacy of mAb against intact C4BP in blocking C4BP binding to heparin-Sepharose was similar to that for blocking 125I-C4BP binding to C4b. In addition, heparin blocked the binding of 125I-C4BP to C4b and vice versa. It is therefore likely that the heparin-binding fragments are localized on or close to the C4b-binding site of C4BP. 相似文献
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Thomas F. Holzman Christine C. Chung Rohinton Edalji David A. Egan Earl J. Gubbins Annemarie Rueter Gail Howard Lana K. Yang Terry M. Pederson Grant A. Krafft et al. 《Journal of Protein Chemistry》1990,9(6):663-672
The gene for human preprorenin was obtained from total RNA prepared from primary human chorion cells. An expression vector was constructed containing an SV40 early promoter, a human preprorenin cDNA, bovine growth hormone poly-A addition signal, and a dihydrofolate reductase (dhfr) expression cassette. This vector was inserted into the DXB-11 Chinese hamster ovary (CHO) cell line. The recombinant protein was exported by CHO cells into the tissue culture media. At harvest the prorenin levels ranged from 1–5 mg/L. For prorenin isolation the cell culture supernatants were processed by filtration, concentration, dialysis, and batch extraction. Preparative-scale isolation of prorenin was accomplished using blue-dye chromatography and size-exclusion chromatography. The isolated prorenin yielded a single SDS-gel band with Mr 40,000. The proprotein was characterized with respect to N-terminal sequence and N-linked sugar composition. Trypsin-activated renin prepared from the proprotein was characterized with respect to N-terminal sequence andpH-activity profile. Enzyme activity was measured with a newly developed fluorogenic peptide substrate containing the P6-P3 sequence of human angiotensinogen. 相似文献
5.
Ronald Bontrop Marcel Tilanus Marlies Mikulski Marja van Eggermond Annemarie Termijtelen Marius Giphart 《Immunogenetics》1986,23(6):401-405
HLA-DR molecules were isolated from eight different HLA-DR3 homozygous B-cell lines by immunoprecipitation with monoclonal antibodies, and they were subsequently analyzed by two-dimensional gel electrophoresis. We found that HLA-DR3 homozygous B-cell lines of consanguineous origin express two types of HLA-DR molecules. One type of HLA-DR molecule was present in all the cell lines tested, whereas the second DR molecule appears to be polymorphic. DNA isolated from the different HLA-DR3 homozygous cell lines was studied by Southern blot analysis to determine whether any DR restriction fragment length polymorphism could be observed. Polymorphisms detected at both the product and genomic level have been compared to each other, and their relations to the serological (HLA-DR) and cellular (HLA-D and LB-Q1) typing data will be discussed.No reprints available 相似文献
6.
Annemarie Surlykke Matija Gogala 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1986,159(2):267-273
Summary MaleThecophora fovea (Tr.) (Noctuidae) sing continuously for several minutes by rubbing the 1. tarsal segment of the metathoracic leg against a stridulatory swelling on the hindwing. In Northern Yugoslavia (Slovenia) the males emerge in late October and start stridulating about a week later when the females emerge.The sounds are pulse trains consisting of 10–12 ms long sound pulses with main energy around 32 kHz and a PRR of 20 pulses/s. The mechanics of the sound producing apparatus was studied by activating the stridulatory swelling with short sound impulses. The impulse response of the swelling was recorded by laser vibrometry and amplitude spectra of the vibrations showed maximum velocities between 25 and 35 kHz. Hence, it seems likely that the stridulatory swelling is driven as a mechanical oscillator with a resonance frequency which determines the carrier frequency of the sounds.Audiograms of both males and females showed peak sensitivities at 25–30 kHz. The median threshold at the BF was 36 dB SPL. The peak intensity of the sound pulses was 83 dB SPL at 1 m, which should enable the moths to hear each other at distances of around 30 m. Therefore sound production inT. fovea might function in long distance calling. It is argued thatT. fovea can survive making such a noise in spite of being palatable to bats because it flies so late in the year that it is temporally isolated from bats.Abbreviations
PRR
pulse repetition rate
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SPL
sound pressure level
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BF
best frequency 相似文献
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Ohne Zusammenfassung 相似文献
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A biometeorological analysis of the daily asthma complaints, classified in 5 degrees of severity, of 50 boys and 25 girls, 7 to 16 years old, at the asthma center Eykeloord (Eastern Netherlands), during 1964 has shown that in winter and early spring the number of asthma attacks in both sexes increased during periods of cooling. The total rise in asthma attacks increased with the length of the cooling period and decreased in relation to the length of the period of warming up. During the summer months June and August these meteorotropic effects were not statistically significant. The observations confirmed the previous findings at an asthma center in the Western Netherlands.
Zusammenfassung Eine biometeorologische Analyse der täglichen Asthmabeschwerden, die in 5 Schweregraden klassifiziert wurden, bei 50 Knaben und 25 Mädchen im Alter von 7 bis 16 Jahren in der Asthmaklinik Eykeloord (Ost-Holland)während des Jahres 1964 hat gezeigt, dass im Winter und Vorfrühling die Anzahl der Asthmaanfälle bei Kälteeinbrüchen zunimmt. Asthmaanfälle nehmen an Zahl mit der Länge der Kälteperioden zu und mit der Länge der Wärmeperioden ab.Während der Sommermonate Juni bis August waren diese Beziehungen zwar auch nachweisbar aber nicht signifikant. Die Beobachtungen bestätigten früheren Ergebnisse in einer Asthmaklinik in West-Holland.
Resume Une analyse biométéorologique des accès d'asthme a montré qu'en hiver et au début du printemps le nombre des dits accès augmente au moment d'une advection d'air froid. Pour ce faire, on s'est basé sur l'observation de 50 garçons et de 25 fillettes de 7 à 16 ans répartis en 5 classes d'acuité de la maladie. Tous étaient en traitement durant l'année 1964 à la clinique pour asthmatiques d'Eykeloord(Hollande orientale). Les accès d'asthme sont d'autant plus nombreux que la période froide est plus longue et leur nombre diminue parallèlement à la durée des périodes plus chaudes. La même relation a pu être établie durant les mois d'été (de juin à août), mais pas de façon significative. Ces observations confirment celles qui avaient été faites antérieurement dans une clinique pour asthmatiques de l'ouest de la Hollande.相似文献
10.
Bertel Møhl Annemarie Surlykke 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1989,165(1):119-124
Summary Two big brown bats (Eptesicus fuscus) were trained to report the presence or absence of a virtual sonar target. The bats' sensitivity to transient masking was investigated by adding 5 ms pulses of white noise delayed from 0 to 16 ms relative to the target echo. When signal and masker occurred simultaneously, the bats required a signal energy to noise spectrum level ratio of 35 dB for 50% probability of detection. When the masker was delayed by 2 ms or more there was no significant masking and echo energy could be reduced by 30 dB for the same probability of detection. The average duration of the most energetic sonar signal of each trial was measured to be 1.7 ms and 2.4 ms for the two bats, but a simple relation between detection performance and pulse duration was not found.In a different experiment the masking noise pulses coincided with the echo, and the duration of the masker was varied from 2 to 37.5 ms. The duration of the masker had little or no effect on the probability of detection.The findings are consistent with an aural integration time constant of about 2 ms, which is comparable to the duration of the cries. This is an order of magnitude less than found in backward masking experiments with humans and may be an adaptation to the special constraints of echolocation. The short time of sensitivity to masking may indicate that the broad band clicks of arctiid moths produced as a countermeasure to bat predation are unlikely to function by masking the echo of the moth.Abbreviations
SPL
sound pressure level
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SD
standard deviation
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SE
standard error
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BW
bandwidth 相似文献