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1.
In this work we describe a non‐invasive and precise technique to record the heartbeats of a spider. A linear output Hall effect transducer in conjunction with a small magnet was used to monitor the micromovements on the dorsal surface of the abdomen of the tarantula Aphonopelma hentzi (Girard) (Theraphosidae). The exoskeleton in this region is in direct contact with suspensory ligaments connected to the heart, and the dorsal cuticle of the opisthosoma moves with each heartbeat. The technique allowed the discrimination of the different stages of the spider's cardiac cycle. The method can be also adapted for a smaller spider or other arthropods. We believe that the method proposed in this paper allows investigators to gain insights into a spider's natural heart rate by gathering unbiased data with a non‐invasive and very precise technique. We have found the resting heart rate of A. hentzi to be 5.6 ± 1.47 beats/min, which is lower than previously reported values. 相似文献
2.
Flávio Resende 《Planta》1936,25(4):665-666
Ohne ZusammenfassungMit 1 Textabbildung (3 Einzelbildern). 相似文献
3.
R Gáspár Z Krasznai T Márián L Trón R Recchioni M Falasca F Moroni C Pieri S Damjanovich 《Biochimica et biophysica acta》1992,1137(2):143-147
Using the whole-cell variation of the patch-clamp technique it has been determined that 0.25-3 mM bretylium tosylate (BT) exerts a repolarizing effect on partially depolarized human lymphocytes. The repolarizing effect was ouabain (40 microM)-sensitive, and was inhibited by the removal of external Na+ or by the Na(+)-channel-blocker amiloride (10-44 microM), but K(+)-channel-blockers 4-aminopyridine (0.1-5 mM) and quinine (100 microM) had no effect. The drug induced a sodium dependent, amiloride-sensitive transient inward current reaching its maximum value approx. 20-30 s after the administration of BT and lasting for 6-10 min. This current was activated by depolarization within 25 ms at around -42 mV, its inactivation took about 2 s and its reversal potential was +24 +/- 5 mV. An increase in the intracellular sodium concentration (1.8-3.2 mM) has been observed upon the addition of BT by monitoring the SBFI fluorescence of the dye-loaded cells. It has been shown that whole-cell K+ currents are significantly decreased by BT. The existence of voltage and ligand (BT)-gated sodium channels has been postulated in human lymphocytes. These channels are thought to participate in the initiation of membrane repolarization in human lymphocytes, and thereby influence mitogenic or antigen-induced cell-activation processes. 相似文献
4.
Turning in MFB-lesioned rats and antagonism of neuroleptic-induced catalepsy after lisuride and LSD.
The effects of lisuride, d-lysergic acid diethyl amide (LSD) and apomorphine were studied in rats with unilateral destruction of nigro-striatal nerve terminals either with 6-hydroxydopamine (6-OHDA) or 5, 6-dihydroxytryptamine (5,6-DHT). Lisuride at the dose of 50 μg kg?1 i.p. induced contralateral turning for more than 4 hours while the circling induced by LSD (200 μg kg?1) and apomorphine (1 mg kg?1) persisted for only one hour. Lisuride, a compound stimulating both dopamine (DA) and 5-hydroxytryptamine (5-HT) receptors induced a more intense turning in 6-OHDA than in 5,6-DHT lesioned rats. This might indicate a modulation of 5-HT on rotational behavior. Haloperidol (1 mg kg?1 i.p.) antagonized both lisuride- and LSD-induced turning. LSD, and much more persistently lisuride, counteracted the prochlorperazine-induced catalepsy. These findings correlate with the biochemical data indicating that lisuride is a very potent agonist at central dopaminergic receptors. 相似文献
5.
6.
Basic fibroblast growth factor (bFGF) was modified by biotinylation via amino group substitution, using biotin-N-hydroxysuccinimide ester at molar reaction ratios of 20, 200, and 2000 per bFGF molecule (respectively named bio-bFGF.20, bio-bFGF.200, and bio-bFGF.2000). The biotinylated bFGF derivatives, bio-bFGF.20 and bio-bFGF.200, conserved the same affinity for heparin as native bFGF, in contrast to bio-FGF.2000 which lost this property. Bio-bFGF.20 and bio-bFGF.200 were as effective as native bFGF in their capacity to compete with 125I-bFGF for binding to bFGF receptor on bovine brain membranes. The biological activity of these bFGF derivatives was tested on CCL39 cells; bio-bFGF.20 and bio-bFGF.200 were as able as native bFGF to promote growth of CCL39. 相似文献
7.
The influence of membrane microviscosity on 5'-nucleotidase activity has been investigated on liver plasma membrane preparations from rats during aging and following diet restriction. In addition the microviscosity of membranes from old rats was changed in vitro by the Active Lipids. During aging the membrane microviscosity increased progressively and in parallel the activity of 5'-nucleotidase decreased. Diet restriction was able to slow down the modification of both parameters. The experiment performed with the Active Lipids further supports that membrane microviscosity modulated the enzyme activity. 相似文献
8.
Dynamic light-scattering studies on the effect of heat and disinfectants on spores of Bacillus cereus. 下载免费PDF全文
A D Molina-Garcia S E Harding L de Pieri N Jan W M Waites 《The Biochemical journal》1989,263(3):883-888
The relative stability of spores of Bacillus cereus grown at three different temperatures was examined by using quasi-elastic light scattering (q.l.s.) in conjunction with turbidity and scanning electron microscopy (s.e.m.). Cultures grown at 20, 30 and 40 degrees C (BC20, BC30 and BC40 respectively) were compared in terms of (i) their effective hydrodynamic radius, rH, as determined from q.l.s. and (ii) their gross morphology, as determined from s.e.m. The effects of autoclaving at 121.1 degrees C on both these properties was also examined. We observed (1) that cultures BC20 and BC30 appeared to have similar values for rH, whereas that of BC40 appeared some 50% higher, and (2) BC40 had a correspondingly much lower heat resistance (its structural integrity was lost after about 20 min autoclaving, whereas that of BC20 and BC30 was retained even after 80 min autoclaving). These data were in good agreement with independent measurements of heat-resistance coefficients. Changes in the hydrodynamic radius, polydispersity (both using q.l.s.) and turbidity were monitored with time on addition of the disinfectants sodium hypochlorite and peracetic acid; again BC40 appeared to have a lower resistance. 相似文献
9.
J P Durand M Bouchonneau J Pieri 《Comptes rendus des séances de la Société de biologie et de ses filiales》1982,176(6):817-823
The non-histone chromosomal proteins from mouse myeloma cell line X 63-Ag 8.653 have been studied using two dimensional polyacrylamide gel electrophoresis. Our results were compared to previous analysis of other myeloma cell lines. 相似文献
10.
Anna Mara Scandroglio Gabriele Finco Marina Pieri Roberto Ascari Maria Grazia Calabrò Daiana Taddeo Francesca Isella Annalisa Franco Mario Musu Giovanni Landoni Ottavio Alfieri Alberto Zangrillo 《BMC anesthesiology》2015,15(1)