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91.
The synthesis of the enantiomers of bupropion, (rac)-2-tert-butylamino-3′-chloropropiophenone 1 (Wellbutrin®) is described. The enantiomers were compared with the racemate in both the tetrabenazine-induced sedation model and the inhibition of uptake of biogenic amine assay. No significant differences were found in their potencies to reverse tetrabenazine-induced sedation in mice or in their IC50 values as inhibitors of biogenic amine uptake into nerve endings obtained from mouse brain. © 1993 Wiley-Liss, Inc.  相似文献   
92.
寡毛实蝇属三新种:(双翅目:实蝇科)   总被引:1,自引:0,他引:1  
本文记述的3新种,即广西实蝇Dacus(Zeugodacus)guangxianus、近黑颜实蝇D.(Zeugodacus)parater和那大实蝇D.(Asiadacus)nadanus,是1982-1985年在南方各地果园中用诱蝇酮(cue-lure)诱获的,寄主不明。所有模式标本均存放于北京农业部植物检疫实验所。在此谨向提供标本的同志致谢。  相似文献   
93.
94.
While feeding, many animals frequently look up and visually scan their environment. Using spectral analysis of continuous series of scan durations from a purple sandpiper Calidris maritima and Barbary doves Streptopelia risoria, we show that there are sequential non-random patterns and significant periodicities in all the examined series such that the birds cycled regularly between short and long scans. The cycles are comparable to those for the continuous series of inter-scan intervals of the same behavioural sequences. We suggest a re-examination of the functional costs and benefits of instantaneous randomness versus sequential predictability in alternating between feeding and scanning and a revision of the models of the way animals alternate between these behaviour patterns.  相似文献   
95.
96.
 Cleavage of double-stranded DNA was performed with cationic manganese porphyrin complexes linked via a spermine tether to the 3′- or 5′-side of triple-helix-forming oligonucleotides (cleaver-TFO conjugates). The targeted sequence was a 15-polypurine sequence present in the env gene of HIV-1 (positions 7301–7315). The presently used TFOs contain only thymine and 5-methylcytosine residues and one adenine at the 3′-end in order to be able to easily introduce a 3′-polyamine linker by reductive amination of the corresponding 3′-apurinic polypyrimidine oligonucleotides. With this method we prepared these TFO-cleaver conjugates in 45% yield with only two equivalents of the Mn-TrisMPyP-COOH precursor. These new metalloporphyrin-TFO conjugates were able to cleave a complementary 45-mer duplex at 10 nM concentration with only ten equivalents of TFO-cleaver. Conjugates without spermine, without 5-methylcytosine, with a random sequence or with the managanese porphyrin-spermine entity on the 5′-end of TFOs were synthesized for comparative studies. Received: 6 December 1995 / Accepted: 5 February 1996  相似文献   
97.
新设的铜脚异丽金龟组包括中国异丽金龟属已知的大型、绿色种类,绝大多数为常见种,彼此形态十分近似。它们是:铜脚异丽金龟(新纪录)Anomala cupripes Hope new record,红脚异丽金龟(新种)A. rubripes sp. nov., 绿脚异丽金龟(新亚种)A. rubripes virescens ssp. nov., 彤脚异丽金龟(新种)A. ignipes sp. nov., 川直异丽金龟A. truncata Bates,滇直异丽金龟(新等级)A. truncata chlorochelys Arrow, stat, nov., 宽角异丽金龟A. expansa Bates,大绿异丽金龟(新种)A. virens sp. nov., 砂尾异丽金龟(新种)A. granuliformis sp. nov. 和檐角异丽金龟(新种)A. planicorna sp. nov.。其中红脚异丽金龟和绿脚异丽金龟是我国南部和台湾的重要害虫,国内外文献中长期误作铜脚异丽金龟引用至今。  相似文献   
98.
It has been proposed that monkeys direct grooming to high-ranking individuals in an attempt to obtain agonistic support in return. But whether these two categories of interactions are causally related has proven difficult to establish. Part of the problem stems from the fact that in stable groups social relationships reflect an equilibrium state and that behaviors need only be performed at low rates and long intervals to maintain the current social structure. In theory, however, if affiliative and supportive interactions are indeed causally related, it should be possible to accentuate their temporal relation, hence their causal dynamics. For example, destabilizing dominance relations can be expected to induce competition for status and force individuals to deploy behavioral tactics for settling new rank relations. We experimentally induced rank reversals in a captive group of Japanese macaques (Macaca fuscata) composed of three matrilines (A-B-C rank order). A reversed C-A-B order composed of three individuals per matriline was maintained for 2 weeks. The results show the close temporal relation among (i) asserting one’s rank, (ii) competing for access to dominants through affiliation and interferences in affiliation, (iii) receiving support from dominants against lower-ranking individuals, and (iv) supporting dominants against subordinates. These findings are compatible with one version of the affiliation-for-support hypothesis, namely that monkeys affiliate with dominants as a way to assert their position in the hierarchy. In a functional perspective, mutual selfishness provides a better explanation than reciprocal altruism because the possibility that both groomers and supporters derive immediate net benefits cannot be excluded.  相似文献   
99.
At elevated osmolarity of the mineral medium M63, marine macroalgae constitute important osmoprotectants and nutrients sources for Escherichia coli. Growth of bacterial population (16 strains) was improved by supplementing M63 salts medium with either aqueous or ethanolic algal extracts obtained from Ascophyllum nodosum, Fucus serratus, Enteromorpha ramulosa, Ulva lactuca, and Palmaria palmata. In their presence, growth was still observed even at 1.02 m NaCl. Furthermore, the E. coli ZB400 growth in presence of whole macroalgae thalli in M63/0.85 m NaCI reached its maximum within 24 h (5 × 107 – 5 × 108 colony-forming units [CFU] per milliliter). In the presence of A. nodosum, bacterial growth was inhibited. In the same experimental conditions, ethanolic extracts improved E. coli growth significantly, because the yield reached 1011 CFU per milliliter. Ulva lactuca and P. palmata allowed the better growth. The Dragendorff-positive compounds extracted from bacterial cells growing on each ethanolic extract exhibited an osmoprotective effect as proved by a disk-diffusion assay. On the other hand, the -onium compounds (quaternary ammonium [betaines] and tertiary sulphonium) and total free amino acid contents of U. lactuca ethanolic extracts were higher than in others. Fucaceae extracts demonstrated especially high protein content. Algal extracts constitute not only an appreciable osmoprotection source for E. coli but also nutrient sources. Correspondence to: J. Minet  相似文献   
100.
The light chain of tetanus neurotoxin (TeNT L chain)has been shown to be endowed with zinc endopeptidaseactivity, selectively directed towards theGln76–Phe77 bond of synaptobrevin, avesicle-associated membrane protein criticallyinvolved in neuroexocytosis. In previous reports,truncations at the NH2- and COOH-terminus ofsynaptobrevin have shown that the sequence 39–88 ofsynaptobrevin is the minimum substrate of TeNT,suggesting either the requirement of a well-definedthree-dimensional structure of synaptobrevin or a rolein the mechanism of substrate hydrolysis for residuesdistal from the cleavage site. In this study, theaddition of NH2- and COOH-terminal peptides ofsynaptobrevin, S 27–55 (S1) and S 82–93(S2), to the synaptobrevin fragment S 56–81allowed the cleavage of this latter peptide by TeNT tooccur. This appears to result from an activationprocess mediated by the simultaneous binding ofS1 and S2 with complementary sites presenton TeNT as shown by surface plasmon resonanceexperiments. All these results favor anexosite-controlled hydrolysis of synaptobrevin by TeNTprobably involving a conformational change of thetoxin. This could account for the high degree ofsubstrate specificity of TeNT and, probably, botulinumneurotoxins.  相似文献   
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