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991.
Metal toxicity on selenastrum capricornutum were examined by batch culture and chemostat culture system. EC50 values under nutrient‐limited condition and saturated condition were compared. The two EC5Os differed by a factor of 10.6 for Cd in batch test, and differed by a factor of 6.5 in continuous test. Both batch and continuous test results indicate that inhibition on algal growth is more severe under nutrient‐limited conditions compared to that under near saturation conditions. Strong correlation, as characterized by the correlation coefficient ρ, were found between the activation level (nutrient requirement) and the tolerance of microorganisms to the toxicant. ρ is equal to 0.9 for the case of Cd in batch test and 0.6 in continuous test. The theory in this study provides generally good estimations to the dose‐response relationship at limiting nutrient conditions. The study indicate that nutrient conditions constitute an important factor in algal toxicity tests. 相似文献
992.
The anticancer drugs: adriamycin, farmorubicin and mitomycin C greatly enhance the generation of hydroxyl radicals (HO.) from H2O2 in the presence of Co(II) ions (CoCl2) at pH 7.4 and 8, as measured by the deoxyribose assay. Catalase, hydroxyl radical scavengers (mannitol, cysteine, glutathione, thiourea, lactic dehydrogenase) inhibited the degradation of deoxyribose confirming that HO‐radicals are responsible for the degradation of the carbohydrate. 相似文献
993.
Singlet molecular oxygen—mediated photooxidation of monochloro and mononitrophenols. A kinetic study
A kinetic and mechanistic study on the aerobic dye sensitized photooxidation of the mono—nitro and chlorophenols was carried out. A singlet molecular oxygen mechanism operates in the photooxidation. Solvent and substituent effects, suggest the intermediacy of a complex with partial charge transfer character, as has been postulated for other phenols. Chemical (reactive) and physical interactions of the substrates with singlet molecular oxygen were discriminated. Quantum yields for photooxidation (higher for the chlorophenols) range from 3 × 10‐2 to 2 × 10‐3, as measured by substrate or oxygen consumption. These values indicate the viability of a singlet molecular oxygen photooxidation as a way for the degradation of nitro and chlorophenol environmental contaminants. 相似文献
994.
Izmit Bay is located at the eastern end of the Sea of Marmara. The Sea of Marmara is an important adjacent area to the Mediterranean Sea. The extent of pollution in the Bay is increased beyond tolerable levels mainly due to substantial and unplanned growth of a large spectrum of industrial activities. A comprehensive project for the prevention and elimination of pollution in Izmit Bay is realised. The assessment of pollution from land‐based sources was the most significant step in this project. The study revealed that the Bay receives a total municipal wastewater flow of 70 000 cu m/day and a total industrial waste discharge of 120 000 cu m/day. The total BOD load was noted to be subdivided as 30 000 kg/day and 75 000 kg/day between municipal and industrial sources respectively. Similar figures were also computed for all the other parameters including nutrients and heavy metals. The evaluation showed that the eastern part of the Bay receives more than 70% of the total pollution load. 相似文献
995.
The effect of the Superoxide radical (O2 –)‐, hydroxyl radical (HO')‐inhibitors, singlet oxygen (1O2)‐quenchers and catalase on the light emission during autoxidation reaction of oxytetracycline was measured. The influence of the 1O2‐quenchers was investigated quantitatively and the rate constants were established. 相似文献
996.
Hydrocarbon emissions from a diesel invert mud residue (DIMR) were monitored while the hydrocarbons were being biodegraded in a solid‐phase bioreactor. Five to twenty percent of the reduction in diesel hydrocarbons was attributed to evaporation depending on the treatment, i.e. homogenization, cultivation, and aeration. Most of these volatile hydrocarbons were linear C8 — C12 alkanes and one‐ring aromatics. Of the treatments aeration had the largest effect on emissions; forced air through the bottom of the bioreactor cells increased emissions by three times over that of the non‐aerated cells. Cultivation increased hydrocarbon emission concentration as much as twofold over the pre‐cultivation value, however, emissions returned to the original levels within 12 hours. Homogenization had the least effect of all treatments. Diurnally, the emission rate was 40% higher in late afternoon than at midnight; the cause of which was probably atmospheric fluctuations such as temperature and solar radiation. The effects of daily atmospheric fluctuations were empirically modeled and taken into account for determining the total volume of emissions. 相似文献
997.
Tomas Brodin Martin I. Lind Miria Kaltiala Wiberg Frank Johansson 《Behavioral ecology and sociobiology》2013,67(1):135-143
Understanding and predicting species range expansions is an important challenge in modern ecology because of rapidly changing environments. Recent studies have revealed that consistent within-species variation in behavior (i.e., animal personality) can be imperative for dispersal success, a key process in range expansion. Here we investigate how habitat isolation can mediate differentiation of personality traits between recently founded island populations and the main population. We performed laboratory studies of boldness and exploration across life stages (tadpoles and froglets) using four isolated island populations and four mainland populations of the common frog (Rana temporaria). Both tadpoles and froglets from isolated populations were bolder and more exploratory than conspecifics from the mainland. Although the pattern can be influenced by possible differences in predation pressure, we suggest that this behavioral differentiation might be the result of a disperser-dependent founder effect brought on by an isolation-driven environmental filtering of animal personalities. These findings can have important implications for both species persistence in the face of climate change (i.e., range expansions) and ecological invasions as well as for explaining rapid speciation in isolated patches. 相似文献
998.
Maud Bonato Matthew R. Evans Dennis Hasselquist Richard B. Sherley Schalk W. P. Cloete Michael I. Cherry 《Behavioral ecology and sociobiology》2013,67(12):1891-1901
One of the most important measures of offspring performance is growth rate, which is often traded off against another important survival trait, immune function. A particular feature of ostrich chicks maintained in farmed environments is that cohorts of chicks vary widely in size. As parents can have a profound effect on the phenotype and fitness of their offspring, we investigated whether chick growth and immune defence were related to variation in levels of immune defence in their genetic parents. As secondary sexual traits of sires could serve as indicators of male quality, and be used in female mating decisions, we also investigated whether chick growth rate and immune defence were related to male plumage and integumentary colouration. We found that offspring growth rates and humoral responses were related to the humoral responses of their parents, suggesting that at least some components of humoral immune capacity are heritable. The white colour of male ostrich feathers was correlated to the humoral response and growth rate of their offspring, suggesting that this visual cue involved in the male courtship display could serve as an important signal to females of male quality, thereby forming the basis of mate choice in this species. 相似文献
999.
Kate D. L. Umbers Nikolai J. Tatarnic Gregory I. Holwell Marie E. Herberstein 《Behavioral ecology and sociobiology》2013,67(3):439-447
Bright colours often communicate important information between conspecifics. In sexually dichromatic species where males exhibit bright colours, two hypotheses are often invoked to explain the function of the colour. First, if a male’s bright colour contains information about his quality, females may prefer brighter males. Equally, male colour may reliably provide other males with information about fighting ability or resource holding potential. In such circumstances, brighter males may win altercations and/or males may use rival colour to assess their likelihood of winning an interaction. In the chameleon grasshopper (Kosciuscola tristis), males but not females turn bright turquoise when their body temperature exceeds 25 °C. In this study, we tested whether the turquoise phase of colour change has a signaling role in inter- and intrasexual contexts. We predicted that females would prefer bright turquoise males over dull males, but found no evidence from several choice experiments to support this hypothesis. We also predicted that brighter males would win more fights than duller males. Whilst we did not find that brighter males won more fights in staged experiments, we found that the brightness of males who chose to enter fights was significantly correlated with their opponents’ brightness. Our results suggest that the brightness of males’ turquoise phase may provide competitors with important information about their rival’s fighting ability. 相似文献
1000.
The photoacclimation capacity of the seagrass Cymodocea nodosa was evaluated considering temporal (i.e. seasonal) and spatial (i.e. depth and within-leaf position) factors of variation. Changes along the leaf were measured in a population growing along a depth gradient (from intertidal to subtidal) in Cadiz Bay (Southern Spain) from 2004 to 2005. Photoacclimation was evaluated by photosynthesis (P–E curves), pigment content and leaf morphology. Plants of Cymodocea nodosa showed large physiological and morphological plasticity (mean %CV = 35.8 ± 3.4) according to the three factors considered. Seasonal patterns appeared for photosynthesis, respiration, pigment content and morphology. Nevertheless, seasonal patterns were not consistent with depth or leaf portions. The resulting data set offered different information depending on the analysis conducted; when only one factor (season, depth or leaf portion) was considered, some tendencies observed in the 3-way full design were masked. Accordingly, considering spatio–temporal variability is crucial when describing photoacclimation and estimating productivity in seagrass meadows. 相似文献