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21.
Alison E. Holliday Travis M. Mattingly Neil J. Holliday 《Physiological Entomology》2015,40(2):131-137
Secretions of an eversible gland on the metathorax of larvae of Chlaenius cordicollis Kirby (Coleoptera: Carabidae) are investigated by headspace analysis using solid phase microextraction followed by gas chromatography‐mass spectrometry (GC‐MS). Larvae from Manitoba, Canada and Pennsylvania, U.S.A., are sampled. Nine presumed defensive compounds are detected when the gland is everted, and this represents the first characterization of defensive secretions of larvae of a carabid beetle. With the exception of a single component (2‐methoxy‐4‐methylphenol), these compounds are distinct from those found in the defensive secretion of adult C. cordicollis. However, seven are more oxidized versions of the alkylphenolic compounds secreted by adult beetles: three hydroquinones (hydroquinone, methylhydroquinone and 2,3‐dimethylhydroquinone) and four quinones (p‐benzoquinone, toluquinone, 2,3‐dimethylquinone and ethyl‐p‐benzoquinone). An additional alkoxyphenol (2‐methoxy‐4‐ethylphenol) is also detected. Two patterns of composition are observed: in one, p‐benzoquinone and hydroquinone are undetectable and the ratio of toluquinone : 2,3‐dimethylquinone is 1 : 4.6 ± 0.6 (mean ± SE); in the other, all nine compounds are detectable and the ratio of toluquinone : 2,3‐dimethylquinone is 1 : 1.0 ± 0.2. These differences in pattern do not appear to be related to geographical source, sex or age of the larvae. 相似文献
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Axenic cultures of Agaricus bisporus were used to show that the rise in ethylene production during fruiting derives from its own metabolism. 相似文献
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P M Wood 《European journal of biochemistry》1977,72(3):605-612
A membrane-bound cytochrome resembling higher plant cytochrome f in many respects has been extracted from the algae Chlamydomonas. Euglena and Anacystis, and partially purified. The spectra of the cytochromes from Chlamydomonas and Euglena are virtually identical to that of parsley cytochrome f, with alpha-band maxima near 554 nm, very asymmetrical beta-bands, and gamma-band maxima at 421 nm. The cytochrome from Anacystis had alpha and gamma-bands both shifted to slightly longer wavelengths. The redox potential of the cytochrome from Chlamydomonas was determined as +350 mV, and its minimum molecular weight in sodium dodecyl sulphate as 31 000. The cytochrome from Euglena showed a rate of reaction with higher plant plastocyanin at least 100 times that of the soluble Euglena cytochrome c-552, and was unaffected by Euglena cytochrome c-552 antiserum. A very fast rate of electron transfer occurred between this cytochrome purified from Euglena and cytochrome c-552. The roles of the membrane-bound and soluble c-type cytochromes in algal photosynthesis are discussed, and it is recommended that the name cytochrome f should be reserved for the membrane-bound cytochrome (to emphasize its affinity with higher plant cytochrome f), while the soluble one should be named by its alpha-band (c-552, c-553, etc.) to make clear its distinctness from higher plant cytochrome f and homology with mitochondrial cytochrome c. 相似文献
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Survival was estimated for shortfin mako Isurus oxyrinchus in the north-west Atlantic from tag-recapture data. The data used in this study were collected by the National Marine Fisheries Service Cooperative Shark Tagging Programme from 1962 to 2003. In total, 6309 shortfin mako sharks were tagged, of which 730 were recaptured. The high recapture rate of 11·6% for this species provided adequate recapture data to carry out survival analyses. Estimates of survival were generated with the computer software MARK, which provided a means for estimating parameters from tagged animals when they were recaptured. The results of several models are presented with various combinations of constant and time-specific survival and recovery rates. A parametric bootstrap and the median variance inflation factor ( ) approach were used to test the fit of the general model to the data. The estimated indicated a very good model fit. The models with time invariant survival rate had the most support from the data and no group or time period effects were found. Recovery rate ( f ) appeared to increase from 0·043 in the early years to 0·056 in the later years. The nominal survival rate of 0·59 year−1 was adjusted with an estimated tag-shedding rate of 0·26 year−1 to generate a final corrected annual survival estimate of 0·79 with a 95% CI of 0·71–0·87. 相似文献