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121.
The amount of struvite (MgNH4PO4·6H2O) produced by Myxococcus xanthus as well as the culture parameter values (pH, total phosphorus, total Kjeldahl nitrogen) were dependent on the culture medium used. Struvite formation started during the exponential phase and the maximum concentration was observed at the beginning of stationary growth phase. The addition of each medium component to the liquid culture influenced the amount of crystal produced. This amount did not depend on the pH increase during the culture period. The moment of the bacterial growth phase, at which each medium component was added, influenced the struvite formation. 相似文献
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Rachèl V. van Schendel G. C. Page-Christiaens Lean Beulen Catia M. Bilardo Marjon A. de Boer Audrey B. C. Coumans Brigitte H. Faas Irene M. van Langen Klaske D. Lichtenbelt Merel C. van Maarle Merryn V. E. Macville Dick Oepkes Eva Pajkrt Lidewij Henneman for the Dutch NIPT Consortium 《黑龙江环境通报》2016,36(12):1091-1098
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Vincent Careau Jean-François Giroux Dominique Berteaux 《Behavioral ecology and sociobiology》2007,62(1):87-96
Food-hoarding animals are expected to preferentially cache items with lower perishability and/or higher consumption time.
We observed arctic foxes (Alopex lagopus) foraging in a greater snow goose (Anser caerulescens atlanticus) colony where the main prey of foxes consisted of goose eggs, goslings, and lemmings (Lemmus and Dicrostonyx spp.). We recorded the number of prey consumed and cached and the time that foxes invested in these activities. Foxes took
more time to consume a goose egg than a lemming or gosling but cached a greater proportion of eggs than the other prey type.
This may be caused by the eggshell, which presumably decreases the perishability and/or pilfering risk of cached eggs, but
also increases egg consumption time. Arctic foxes usually recached goose eggs but rarely recached goslings or lemmings. We
tested whether the rapid-sequestering hypothesis could explain this recaching behavior. According to this hypothesis, arctic
foxes may adopt a two-stage strategy allowing both to maximize egg acquisition rate in an undefended nest and subsequently
secure eggs in potentially safer sites. Foxes spent more time carrying an egg and traveled greater distances when establishing
a secondary than a primary cache. To gain further information on the location and subsequent fate of cached eggs, we used
dummy eggs containing radio transmitters. Lifespan of primary caches increased with distance from the goose nest. Secondary
caches were generally located farther from the nest and had a longer lifespan than primary caches. Behavioral observations
and the radio-tagged egg technique both gave results supporting the rapid-sequestering hypothesis. 相似文献
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P Leone M Nègre M Gennari V Boero R Celis J Cornejo 《Journal of environmental science and health. Part. B》2001,36(2):127-142
Adsorption of the imidazolinone herbicides imazapyr, imazethapyr and imazaquin was studied on two binary systems (ferrihydrite-humic acid) prepared by treating ferrihydrite (Fh) immediately after its precipitation with a soil humic acid (HA) at different loadings (4% and 8% HA content), and on a blank ferrihydrite sample prepared in the same way, but without HA addition. Imidazolinone adsorption on pure Fh and on the 4% Fh-HA decreased with increasing of the herbicide hydrophobicity (imazaquin相似文献
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Astract Northern anchovy larvae, Engraulis mordax, were collected on five cruises covering the Southern California Bight, one cruise in April 1984, four cruises in January, February and May 1986. The amounts of triacylglycerol, cholesterol and polar lipid were measured in individual anchovy larvae as indicators of their nutritional condition. There was a significant difference in each of the size-specific lipid components between the stations for four of the five cruises. This indicates that all the ocean habitats within a cruise were not equal in promoting growth (and presumably survival) in the anchovy larvae. There were also differences between cruises, where the percentage of the larvae judged to be in poor condition varied from 8 to 27%. Canonical correlation analyses revealed a significant relationship in most cases between the larval fish parameters and the physical and biological data collected from each occupied station. Cholesterol and triacylglycerol were the most important larval components, and the short-term energy storage component in the copepod Calanus pacificus was the most important station component. The data, however, are not sufficient to identify and characterize stations in the field which produce anchovy larvae in good condition. 相似文献