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41.
42.
Adult and juvenile common marmosets were introduced to unfamiliar conspecifics individually and in whole groups. In introductions
using animals of the same sex, adults were mutually hostile unless they were related or socially familiar; juveniles behaved
submissively to adults and little aggression was observed between juveniles. In introductions using animals of the opposite
sex, males of all ages solicited females but females did not reciprocate. When whole groups were introduced, in two experiments
most of the elder group members behaved aggressively and younger animals did not interact frequently; but in a third experiment,
in which the adult males were related, little aggression was observed and younger animals behaved amicably. It is argued that
the behavioral reactions shown by individual marmosets are related to territorial hostility and that the behavior of juveniles
to adults may aid assimilation of younger animals into new groups. 相似文献
43.
WILLIAM L. KRINSKY 《The Journal of eukaryotic microbiology》1977,24(1):52-56
SYNOPSIS. Nosema parkeri sp. n. is described from nymphs and adults of the argasid tick, Ornithodoros parkeri Cooley, from a laboratory colony. Schizogonic and sporogonic stages are described from various tick tissues. Spores are binucleate, measuring 3.2 (3–4) × 1.9 (1.8–2.5) μm. Transmission is transovarial and transstadial. The parasite does not appear to affect adversely the development or reproduction of the tick. Dermacentor andersoni Stiles was experimentally infected. Attempts to infect Swiss mice by tick feeding or by injection of infected tick suspensions were unsuccessful. The microsporidan differs in structure from Encephalitozoon ixodis Weiser) and Nosema slovaca Weiser & Reháček, the only other microsporidans known from ticks. 相似文献
44.
Roberta Bertelli Fabrizio Ginevri Rosanna Gusmano Gian Marco Ghiggeri 《In vitro cellular & developmental biology. Animal》1991,27(10):799-804
Summary It has been suggested that the generation of toxic radicals plays an important role in toxicity by Adriamycin (ADR) on cancer
cell lines and in vivo. We have examined the role of free radicals in determining toxicity and resistance to ADR of rat glomerular
epithelial cells in culture; this method provides a good model for analyzing the mechanisms responsible for ADR experimental
nephrosis in rats. Three points were established: a) the intra- or extracellular site of ADR toxicity; b) the role of the
superoxide anion and of the hydroxyl radical in determining intra- and-extracellular cytotoxicity; and c) the implication
of oxido-reduction cycling as a potential route for ADR semiquinone transformation. Free ADR was found to induce the same
inhibition of [3H]thymidine incorporation into DNA as ADR bound to an agarose macroporous bed which prevents the intracellular incorporation
of the drug. Specific scavenging of free radical activity by the enzymes catalase and superoxide dismutase, the hydroxyl radical
inhibitors dimethyl sulfoxide and dimethylthiourea (DMTU) and by chelation of intracellular free iron with deferoxamine produced
only a partial restoration of [3H]thymidine incorporation into DNA, which was maximal for DMTU (30% of normal incorporation). DMTU treatment was unsuccessful
in preventing the extracellular cytostatic effect of ADR. Finally, glomerular epithelial cell killing (51Cr-release method) by 5-iminodaunorubicin, an ADR analogue with a modified quinone function that prohibits oxido-reduction
cycling, was higher than unmodified ADR. These results indicate that ADR may exert its cytotoxic effects on glomerular epithelial
cells by interaction at the cell surface, whereas the intracellular compartment, principally DNA, does not seem to be the
target of ADR effects. They also suggest that the free radicals are in part responsible for ADR intracellular cytotoxicity,
but other mechanisms should also be hypothesized. Finally, the participation of the ADR semiquinone radical in oxido-reduction
cycling seems not important for the induction of the cellular damage. 相似文献
45.
Calvet S Clapés P Vigo JP Xaus N Jorba X Mas RM Torres JL Valencia G Serralheiro ML Cabral JM Empis JM 《Biotechnology and bioengineering》1992,39(5):539-549
The influence of five different N-terminal protecting groups (For, Ac, Boc, Z, and Fmoc) and reaction conditions (temperature and dimethylformamide content) on the alpha-chymotrypsin-catalyzed synthesis of the dipeptide derivative X-Phe-Leu-NH(2) was studied. Groups such as For, Ac, Boc, and Z always rendered good peptide yields (82% to 85%) at low reaction temperatures and DMF concentrations, which depended on the N-alpha protection choice. Boc and Z were the most reactive N-alpha groups and, in addition, the most suitable for peptide synthesis. On the other hand, the use of empirical design methodologies allowed, with minimal experimentation and by multiple regression, to deduce an equation, which correlates the logarithm of the first order kinetic constant (log k') with reaction temperature, DMF concentration, and hydrophobicity (log P values) of the different protecting groups. The predictive value of the equation was tested by comparing the performance of another protective group, such as Aloc, with the performance predicted by said equation. Experimental and calculated k' values were found to be in good agreement. 相似文献
46.
47.
Dr. Edward B. Blanchard Ann E. Taylor Mark P. Dentinger 《Applied psychophysiology and biofeedback》1992,17(3):179-202
Data are presented from a prospective clinical replication series of ten consecutive high-medication headache patients who presented for nondrug treatment of their headaches. For the first eight, an attempt was made to withdraw the patients from medication, with the assistance of relaxation training, prior to entering a comprehensive self-regulatory treatment program. For the last two, drug withdrawal accompanied the treatment. Six of the ten patients showed clinically significant reductions in headache activity, which held up over follow-ups of up to 12 months. Psychological tests provide some discrimination between success and failures.This research was supported in part by a grant from NINDS, No. NS-23340. Appreciation is expressed to Dr. Kenneth A. Appelbaum and Ms. Denise Michultka for their roles in this study. 相似文献
48.
John J. Shea 《Evolutionary anthropology》1992,1(4):143-150
Stone tools are the most durable and ubiquitous residue of prehistoric hominid activity. For this reason, archeologists attempt to learn as much as possible about hominid behavior from the analysis of lithic artifacts. Lithic microwear analysis reconstructs aspects of stone-tool use from patterned variation in the traces of microscopic wear on those tools. The analysis of lithic microwear traces has increased our understanding of how stone tools were used in contexts ranging from the early Pleistocene to the ethnographic present. 相似文献
49.
The possibility that the feeding rates of larvae of S. austeni and S. lineatum are influenced by the nature of the food material is considered in relation to natural river conditions and laboratory feeding experiments. Diatoms appeared to be the most satisfactory food source and bacteria (Pseudomonas) the poorest. Simuliid larvae attain high assimilation efficiencies when feeding on diatoms but the proportion of river suspended solids which they assimilate is probably very low. 相似文献
50.
Summary Each primary micromere and macromere of the D-quadrant ofDentalium was deleted, through the mesentoblast stage, to investigate the way in which the polar lobe cytoplasm exerts its influence on development.-D and -1D embryos form an apical tuft but no posttrochal structures.-2D embryos form an apical tuft and a reduced posttrochal region without a shell. -3D and -4D are externally similar to control embryos. -1d embryos and -1c embryos have an apical tuft with a reduced number of cilia. Embryos in which both 1c and 1d are deleted lack the apical tuft.-2d embryos lack shell and most other posstrochal structures. -3d and-4d embryos appear externally equivalent to controls.The polar lobe cytoplasm exerts its influence sequentially, and as inIlyanassa the maximal effect is at the third quartet stage. 相似文献