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91.
利用聚丙烯酰胺凝胶电泳分析了泥蚶(Tegillarca granosa)能量代谢相关的10种同工酶。酯酶和α-淀粉酶是同能量吸收有关的酶,主要分布于消化腺里。苹果酸脱氢酶、苹果酸酶、异柠檬酸脱氢酶、琥珀酸脱氢酶、醇脱氢酶、乳酸脱氢酶、6-磷酸葡萄糖脱氢酶和三磷酸腺苷激酶是与能量代谢相关的酶。泥蚶的能量供应有3种途径:有氧呼吸、无氧酵解和磷酸戊糖途径。从泥蚶体内含有很高活性的6-磷酸葡萄糖脱氢酶可知,磷酸戊糖途径是泥蚶糖代谢的主要途径,NADP为供能体。同其它贝类相比,泥蚶的三磷酸腺苷激酶的活性很低,这与它们的埋栖生活不活跃运动的习性是一致的。 相似文献
92.
Obied HK Bedgood D Mailer R Prenzler PD Robards K 《Journal of agricultural and food chemistry》2008,56(19):8851-8858
Olive mill waste (OMW) contains substantial amounts of valuable antioxidant biophenols that can be recovered for possible applications in food, pharmaceutical, and cosmetic industries. However, the impact of cultivar, harvesting time, and seasonal variation on the phenolic composition of OMW has not yet been assessed. Total phenols, antioxidant activity, and phenol profiles of OMW extracts from five different Australian-grown cultivars (Barnea, Correggiola, Manzanillo, Mission, and Paragon) were studied at four different harvesting times in the 2004 season. The impact of seasonal variation was assessed by comparing total phenol content, antioxidant activity, and phenol profile of two cultivars (Correggiola and Mission) harvested in the 2004 and 2005 seasons. The phenol content and antioxidant activity at different harvesting times were mainly a function of the olive cultivar. Harvesting time had a quantitative effect rather than a qualitative effect on the phenol profile. Intercultivar and harvesting time variation accounted for a 2-5-fold change in the total phenol and antioxidant capacity, while levels of individual biophenols experienced up to 50-fold change. The phenol content and antioxidant capacity of OMW significantly changed between seasons with different variation patterns for different cultivars. 相似文献
93.
Frank-Thorsten Krell Arthur Y.C. Chung Emma DeBoise Paul Eggleton Alessandro Giusti Kelly Inward Sylvia Krell-Westerwalbesloh 《Pedobiologia》2005,49(2):175-186
Winkler extractors, a simple device presumed to extract macro-invertebrates efficiently from soil and litter samples, is being used increasingly in ecological surveys and functional studies of soil macro-invertebrate communities. In this study the extraction efficiency and taxonomic bias of the Winkler extraction are evaluated for extraction periods of 3 h up to 7 weeks, calibrated by hand-sorting after 7 weeks. The method extracts most macro-invertebrates completely or to a proportion of over 90% except Isopoda, Diplopoda and Mollusca. However, for an exhaustive result, a long extraction period of several weeks is necessary. For the most speciose group (adult beetles) and for the commonly most abundant group (ants), a short extraction of 3 days was sufficient to get 70% of the individuals and nearly all species. Three days was also sufficient to recover the rank abundance order of beetle families, while for ‘higher taxa’ and for Chilopoda species, 4 and 3 weeks were necessary, respectively. Optimum extraction times for the abundant macro-invertebrate groups and possible adjustment factors for the soil macro-invertebrates of temperate woodlands are proposed to compensate the taxonomic bias caused by short extraction periods. However, for recording an accurate snapshot of the soil and litter fauna at a particular time, shorter extraction periods are advisable because of the short life cycle of many soil invertebrates causing emergence of later stages or a second generation during longer extraction periods. The problem of contamination of samples is also discussed. 相似文献
94.
Jessi L. Brown Michael W. Collopy Paul W. Juergens W. Grainger Hunt 《Biological conservation》2006,131(3):453-458
The northern aplomado falcon (Falco femoralis septentrionalis) has been the subject of a large-scale reintroduction effort conducted by The Peregrine Fund since 1993. Intensive monitoring during 2002-2004 revealed approximately 38 breeding pairs and numerous non-territorial individuals in two study areas centered on Matagorda Island National Wildlife Refuge (NWR) and Laguna Atascosa NWR. Continued releases (“hacking”) of captive-bred young after pair establishment and successful wild breeding provided an opportunity to compare survival and recruitment histories of wild-reared and hacked falcons hatched during 2001-2003. We used Program MARK to rank multi-state models of apparent survival and recruitment rates with Akaike’s Information Criterion scores, corrected for small samples. The top model candidate, with almost 3.5 times more support than the next best model, detected differences due to falcon origin (wild or captivity): although breeder survival was independent of origin, juvenile hacked falcons survived and recruited at lower rates than wild-reared falcons. Given the high density of territorial adult falcons in the study areas, the difference in apparent survival may reflect greater dispersal by hacked falcons, increased tolerance of wild falcons in territory margins due to prior socialization, or other factors effecting higher intrinsic fitness of wild falcons. However, natal dispersal did not differ between the two groups, strengthening the hypothesis of a difference in true survival. Disproportionately greater recruitment of wild falcons into the breeding population again suggests their higher intrinsic fitness. These findings show how close monitoring of population vital rates can efficiently guide adaptive management of recovering populations. 相似文献
95.
Robert J. Diaz Lars Johan Hansson Rutger Rosenberg Paul C. Gapcynski Michael A. Unger 《Water, air, and soil pollution》1993,66(3-4):251-266
It is possible to rapidly detect the presence of high concentrations of sediment associated hydrocarbons using a sediment profile camera and simultaneously evaluate the general sedimentological and biological character of a contaminated area. In sediments that were heavily contaminated with hydrocarbons from spills and chronic long-term additions the presence of hydrocarbons was seen about 50% of the time in the sediment profile images as unique features, ‘H spots’. The presence of these features was related to the concentration of hydrocarbons in the sediment. In highly contaminated muddy sediments ‘H spots’ were found in images collected at stations that had from 270 to 610 ppt total hydrocarbons. Sedimentological and biological information obtained from the sediment profile images confirmed the impacted nature of Elizabeth River sediments. Sediment profile imaging provide a means of obtaining an overall evaluation of the quality of a habitat and impacts on that habitat from pollution related environmental disturbances. While qualitative, an advantage of sediment profile image data is that they can be evaluated in less than a day and used to quickly locate inclusions of hydrocarbons in the sediments for further quantitative chemical or biological sampling, or mapping of heavily contaminated areas. 相似文献
96.
Marko Debeljak Jrme Cortet Damjan Demar Paul H. Krogh Saso Deroski 《Pedobiologia》2007,51(3):229-ECOGEN
The population dynamics of soil organisms under agricultural field conditions are influenced by many factors, such as pedology and climate, but also farming practices such as crop type, tillage and the use of pesticides. To assess the real effects of farming practices on soil organisms it is necessary to rank the influence of all of these parameters. Bt maize (Zea mays L.), as a crop recently introduced into farming practices, is a genetically modified maize with the Cry1Ab gene which produces a protein toxic to specific lepidopteran insect pests. To assess the effects of Bt maize on non-target soil organisms, we conducted research at a field site in Foulum (Denmark) with a loamy sand soil containing 6.4% organic matter. The study focused on populations of springtails (Collembola) and earthworms (Oligochaeta) from samples taken at the beginning and at the end of the maize crop-growing season during 2 consecutive years. Farming practices, soil parameters, the biological structure of soil communities, and the type and age of the crop at the time of sampling, were used as attributes to predict the total abundance of springtails and biomass of earthworms in general and the abundance or biomass for specific functional groups (epigeic, endogeic and anecic groups for earthworms, and eu-, eu to hemi-, hemi-, hemi to epi- and epiedaphic groups for Collembola). Predictive models were built with data mining tools, such as regression trees that predict the value of a dependent variable from a set of independent variables. Regression trees were constructed with the data mining system M5′. The models were evaluated by qualitative and quantitative measures of performance and two models were selected for further interpretation: anecic worms and hemi-epiedaphic Collembola. The anecic worms (r2=0.83) showed preferences for less clay and more silt soil with medium pH but were not influenced directly by farming practices. The biomass of earthworms was greater in early autumn than in spring or late autumn. Biomass of hemi-epiedaphic Collembola (r2=0.59) increased at the end of the maize growing season, while higher organic matter content and pH tended to increase their biomass in spring. Greater abundance of Collembola was also noted in early autumn if the crop was non-Bt maize. The models assessed by this research did not find any effects of the Bt maize cropping system on functional groups of soil fauna. 相似文献
97.
Byun Y Whiteside S Cooksey K Darby D Dawson PL 《Journal of agricultural and food chemistry》2011,59(4):1428-1431
A nanoencapsulation technique was applied to an oxygen-scavenging system, and thermal processing was investigated as an activator to trigger the oxygen-scavenging reaction. α-Tocopherol-loaded polycaprolactone (PCL) nanoparticles (NPs) were prepared using an oil-in-water emulsion solvent evaporation method. The influences of iron(II) chloride, water, and thermal processing on the oxygen-scavenging capability were investigated. NPs without iron(II) chloride, moisture, and thermal processing had no oxygen-scavenging effect. However, the oxygen content (%) in the cup headspace of 20.9% decreased to 20.4% when the oxygen-scavenging system contained NPs, water, and iron(II) chloride. The oxygen content (%) decreased further to 19.5% when water was eliminated from the mixture. In this research, NPs and iron(II) chloride with thermal processing had an oxygen-scavenging capacity of 6.44 cm3 of O2/g and an oxygen-scavenging rate of 0.21 cm3 of O2 g(-1) day(-1). Results indicated that NPs and iron(II) chloride in an oxygen-scavenging system can be used as a heat-activated oxygen scavenger. 相似文献
98.
Lloyd R. Stark William R. Wenerick Frederick M. Williams S. Edward Stevens Jr. Paul J. Wuest 《Water, air, and soil pollution》1994,75(3-4):405-420
Four volumes of spent mushroom compost were exposed to synthetic coal mine drainage (pH 3.5, 48 mg L?1 Fe, 22 mg L?1 Mn) under oxidizing conditions (Eh 300 to 400 mV) at a relatively high rate of flow. After 15 days, the compost lost its ability to elevate pH, to lower the redox potential, to lower outlet iron concentrations, and to lower manganese concentrations, with larger volumes retaining more Fe and H+, but less Mn. Estimated retention maxima per liter of spent mushroom compost were 281 μeq H+, 5.56 g Fe, and 0.15 g Mn. These values are similar to those reported elsewhere for peat. The ‘saturated’ compost was then mixed and exposed to mine water in order to eliminate ‘dead zones’ in the compost. Subsequently, the compost was re-exposed to synthetic mine water (pH 4.0, 60 mg L?1 Fe, O mg L?1 Mn) under a much lower flow rate and less oxidizing regime for a period of 114 days. Under the low flow regime, iron was first exported from the compost as reducing conditions were established, and then retained on a stable basis. In addition, Eh was lowered and pH was elevated by the compost. On a net basis, the capacity of the compost to retain iron was increased and apparently stable under the decreased flow conditions. 相似文献
99.
Paul E Waggoner 《Agricultural and Forest Meteorology》1984,33(1):53-65
The skewed course of hatching of gypsy moth eggs is represented by a mathematical model embodying the conception that the eggs begin at location 0 in development space and progress at a rate that is the reciprocal of the time when the first eggs hatch because they reach location 1 in space. During their progress, a daily fraction is delayed for a period and then progresses again from the location in space from which it was delayed. Theoretically, the course of hatching is represented by a Poisson function, with the usual mean replaced by the product of the daily fraction delayed and the time of first hatch. A time referred to the time of first hatch and adjusted for the period of delay replaces the usual number whose frequency is calculated. Skewness significantly exceeded the expected 0 of the Normal curve in 79% of 91 experiments at steady temperature, whereas it exceeded the expected skewness of the Poisson in only 35%. The times of first hatch and of delay and the daily fraction delayed changed in an orderly fashion from 12 to 33°C. In 43 experiments with changing temperature in the laboratory, the course of hatching was predicted by numerical integration of the parameters observed at steady temperature. The standard deviation of the difference between observation and prediction was day for the time of first hatch and the mean time of individual hatches; it was days-squared for the variance and unit for the skewness. In six outdoor experiments from spring to autumn, the entire courses of hatching were predicted reasonably well, and the means were predicted more consistently than by a method of degree-days. 相似文献
100.
Paul E. Waggoner 《Agricultural and Forest Meteorology》1985,36(1):43-53
Although eggs of the gypsy moth Lymantria dispar (L.) supercool, a steady and substantial portion freezes and dies at a steady temperature below ?26°C. The rate of freezing at steady temperature is about 1% per min at ?27°C and changes about tenfold per degree. The freezing of the eggs at varying temperature is predicted by integration of the rates observed at steady temperature. 相似文献