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991.
Yellow-legged gull Larus michahellis populations have been studied on three archipelagos consisting of 20 islands distributed along 80 km of the French Mediterranean
coastline. Population changes were analyzed between 1920 and 2006. In the first decades following their settlement on these
islands, the yellow-legged gull populations showed a continuous exponential growth in the three archipelagos, in agreement
with an annual geometric growth rate λ above 1. The population growth ceased to fit this model during the 1980s for the older
colonies (Riou and Hyères Islands archipelagos). Thus, we focused on population changes occurring during the period 1982–2000,
a pivotal period for which we have both precise census and anthropogenic food resource data, in order to determine environmental
factors influencing these population changes using multiple linear regression models. An average annual growth rate of colony
size was 1.02 for the last two decades. The changes in landfill availability, the gull density in 1982, and the nesting area
in 1982 explained 84.4% of variation in colony size changes between 1982 and 2000. The yellow-legged gull changes on the islands
in the last two decades increased as availability in anthropogenic food resources increased near the colony (positive ΔK).
As a consequence, given no reduction in landfill activity or in accessibility for gulls, we expect this region to sustain
continuous species expansion in the future. 相似文献
992.
The four glucose-phosphorylating isozymes from rat liver were separated by DEAE-cellulose column chromatography at several ages during development. The isozymes exhibited a sequential mode of appearance. The isozymes A, B, and C reached maximal values of activity at days +1, +3, and +7, respectively, decaying afterwards to the low characteristic adult value. Isozyme D activity was detected in very low levels as early as day +3, rising from day +18 to reach constant adult values at day +30. A fraction of the glucose phosphorylating activity was found associated with particulate material in prenatal and newborn rats. From day +15 onwards, no particulate activity could be detected. The particulate activity was found to be composed of three low-Km isozymes as of the corresponding soluble fraction. 相似文献
993.
994.
M L de Ceballos A E Lopez J R Harto A Bravo I Gomez-Monterrey R Gonzalez-Mu?iz M T Garcia-Lopez J del Rio 《Peptides》1992,13(1):63-67
Peptide bond substitution in the molecules of Lys-Trp(Nps) (LTN) and Trp(Nps)-Lys (TNL) by an aminomethylene and ketomethylene bond, respectively, afforded pseudodipeptides with analgesic activity. The new compounds Lys psi(CH2NH)-Trp(Nps)-OMe (LTNAM) and Trp(Nps)psi(COCH2)(R,S)-Lys (TNLKM) induced a dose-dependent and naloxone-reversible analgesia following intracerebroventricular (ICV) administration to mice. The antinociceptive effects were longer lasting compared to those induced by the parent compounds. The pseudodipeptides protected Met-enkephalin degradation by rat striatal slices and, combined with an ineffective dose of the opioid peptide, induced analgesia. LTNAM and TNLKM were as potent as LTN to inhibit brain aminopeptidase in vitro and ex vivo. An increased resistance to proteolysis of the pseudodipeptides may explain their prolonged analgesic activity. 相似文献
995.
996.
Alejandra Bravo Rodolfo Quintero Claudia Díaz Alfredo Martínez Mario Soberón 《Applied microbiology and biotechnology》1993,39(4-5):558-562
A Bacillus thuringiensis respiratory mutant (AB1 strain) that shows premature sporulation and insecticidal crystal protein (ICP) production was isolated. The mutant strain harbours the cryIC and cryID insecticidal genes and could be important for the production of ICP highly toxic to Spodoptera sp. The mutant was selected by its increased capacity to oxidize. N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD). In this strain, cytochrome aa
3 expression is not repressed during the sporulation phase, in contrast with the wild-type strain. The growth, spore production, dissolved O2, O2 consumption, CO2 evolution rate and ICP production were recorded as a function of time. The AB1 mutant strain has a similar growth yield to the wild-type strain, but begins sporulation at least 4 h earlier. The AB1 strain consumes 74.5% more O2 than the wild-type strain, during the fermentation process. The mutation on strain AB1 has an important positive effect on ICP production. This procedure shows that ICP production could be increased during fermentation by increasing the respiration capacity of Bacillus thuringiensis.
Correspondence to: A. Bravo 相似文献
997.
998.
999.
Summary Polyionic hydrogels have been prepared by complexation of chitosan and xanthan. These hydrogels have been used to immobilize lipase from porcine pancreas (E.C. 3.1.1.3). Immobilization efficiency varied between 90 and 99% of initial activity. Immobilized lipase retained its activity towards hydrolysis of olive oil in water as an emulsion and of olive oil in isooctane. 相似文献
1000.
Hélène Moffet Carol L. Richards Francine Malouin Gina Bravo Gaston ParadisAuthor vitae 《Journal of electromyography and kinesiology》1998,8(6):411-422
The relationship between the type of meniscal lesion (bucket-handle, flap or degenerative tears) and preoperative knee function (5.1±6.2 days before arthroscopic meniscectomy) was studied in 35 patients. Patients with bucket-handle tears (group B, n=12) had large knee extension work deficits during maximal voluntary contractions at 30° and 180°/s (Kin-Com dynamometer). These work deficits were accompanied by proportional decreases in the prime mover or agonist-EMG levels (VM: vastus medialis and/or VL: vastus lateralis). These patients had smaller deficits during flexion movements at 30°/s. Moreover, a larger number of negative clinical signs and symptoms (pain at rest and during tests, locking, thigh atrophy, extension and flexion movement deficits larger than 10°) were found with an equal or a higher prevalence in group B than in the other groups. Patients with flap tears (group F, n=15) had deficits in work and agonist-EMG activity (VM and VL) only during the extension tests. In contrast, patients with degenerative tears (group D, n=8) had a work deficit and a concomitant decrease in the EMG level of the medial gastrocnemius (MG), only during the flexion test at 30°/s. Comparable mean knee function scores, as measured by the Lysholm and Gillquist questionnaire [35], were obtained for the three groups of patients, suggesting that this measure was not sensitive enough to discern functional differences related to types of meniscal tears. The results of this study have demonstrated a link between the type of meniscal lesion and the consequent preoperative knee joint disability profile as defined by comparison with the sound leg. These results emphasize the need to consider meniscal lesion type and an individual's preoperative strength deficit when group comparisons of patients are made or the effects of therapy (arthroscopic surgery and rehabilitation) are evaluated. 相似文献