Effects of petroleum hydrocarbons on the hepatic cytochrome P450 1A1 system in rainbow trout   总被引：1，自引：0，他引：1  

Malin Celander  Dag Broman  Lars Frlin  Carina Nf 《Marine environmental research》1995,39(1-4)

Effects on the hepatic cytochrome P450 1A1 system were investigated in juvenile rainbow trout i.p. injected with three different aromatic containing fractions: kerosene, light gas oil or heavy gas oil, originated from distilled North Sea crude oil. Kerosene treatment resulted in no effect on the P450 1A1 system, light gas oil injection caused a weak induction of EROD activities and heavy gas oil treatment resulted in a prominent induction of EROD activities as well as accumulation of CYP1A1 mRNA and P450 1A1 protein levels. The effects of heavy gas oil were compared with effects of β-napthoflavone (β-NF) on the P450 1A1 system. It was obvious that important discrepancies seemed to exist between EROD activities and corresponding CYP1A1 mRNA and P450 1A1 levels in rainbow trout treated with either heavy gas oil or β-NF i.e. heavy gas oil treatment resulted in higher specific EROD activities (EROD/P450 1A1) compared to β-NF. GC-MS analyses revealed that liver and bile from heavy gas oil treated rainbow trout in addition to naphthalene also contained polycyclic aromatic hydrocarbons such as phenanthrenes, anthracene, pyrenes, fluoranthene benz(a)anthracene and chrysene, while none of these compounds were detected in control trout.  相似文献   

Quantification of cytochrome P4501A1 and catalytic activities in liver microsomes of isosafrol- and β-Naphthoflavone-treated rainbow trout (Oncorhynchus mykiss)     

Malin Celander  Lars Frlin 《Marine environmental research》1992,34(1-4)

The effects of isosafrol (ISF) or β-naphthoflavone (βNF) treatments on cytochrome P450 (P450) levels in rainbow trout liver were investigated using immunochemical and catalytic techniques. The discrepancies in catalytic activities and ELISA quantification of rainbow trout P4501A1 protein levels between ISF- and βNF-treated fish indicate that important differences exist between the responses induced by βNF and ISF treatments in the rainbow trout liver.  相似文献   

The use of polyclonal antibodies raised against rat and trout cytochrome P450 CYP1A1 orthologues to monitor environmental induction in the channel catfish (Ictalurus punctatus)     

M.J.J. Ronis  Malin Celander  Lars Frlin  Thomas M. Badger 《Marine environmental research》1992,34(1-4)

Induction of hepatic cytochrome P450-dependent microsomal mono-oxygenase by xenobiotics is a well-established phenomenon in teleost fish. As in laboratory mammals, fish possess multiple forms of cytochrome P450 that display overlapping substrate specificity. One such isoform, CYP1A1, which has been cloned and sequenced from rainbow trout, has been shown to be orthologous to rat CYP1A1 and, as in mammals, is inducible up to several hundred-fold by planar aromatic hydrocarbons, PCBs and dioxins. It has been suggested that induction of CYP1A1 orthologues might provide a sensitive biomonitor for environmental pollution by mixtures of such compounds. In the current study, polyclonal antibodies directed against CYP1A1 purified from rat and trout liver were used to monitor induction of the CYP1A1 orthologue in hepatic microsomes from the fresh water species, the channel catfish (Ictalurus punctatus). Catfish from a local fish farm were induced in the laboratory by three daily injections of 50 mg/kg of the PCB mixture Aroclor 1254 and compared with fish taken from a site in central Arkansas—the Bayou Meto, known to be polluted with dioxin. Hepatic microsomal activities towards ethoxyresorufin (EROD) and pentoxyresorufin (PROD) were measured and Western blot analysis carried out with the two antibodies. EROD was elevated in both the Aroclor-treated fish and in the Bayou Meto fish compared with untreated fish farm controls; smaller but significant increases were observed in PROD. Spearman's rank correlations of 0·74 and 0·89 were observed between EROD and immunoquantified cross-reactivity towards the rat CYP1A1 and trout CYP1A1 antibodies.  相似文献   

Ultraviolet dust aerosol properties as observed by MARCI     

Michael J. Wolff  R. Todd Clancy  Michael C. Malin 《Icarus》2010,208(1):143-2499

Observations by the Mars Color Imager (MARCI) on board the Mars Reconnaissance Orbiter (MRO) in two ultraviolet (UV, Bands 6 and 7; 258 nm, and 320 nm, respectively) and one visible (Band 1, 436 nm) channels of the 2007 planet encircling dust storm are combined with those made by the two Mars Exploration Rovers (MERs) to better characterize the single scattering albedo (ω₀) of martian dust aerosols. Exploiting the low contrast of the surface in the UV (and blue) as well as the reduced importance of surface reflectance under very dusty conditions, we utilize the sampling of photometric angles by the MARCI cross-track geometry to synthesize an analog of the classical Emergence Phase Function (EPF). This so-called “pseudo-EPF”, used in conjunction with the “ground-truth” measurements provided by the MERs, is able to effectively isolate the effects of the dust ω₀. The motivation for this approach is the elimination of a significant portion of the type of uncertainty involved in many previous radiative transfer analyses. Furthermore, we produce a self-consistent set of complex refractive indices (m=n+ik) through our use of an explicit microphysical representation of the aerosol scattering properties. Because of uncertainty in the exact size of the dust particles during the epoch of the observations, we consider two effective particle radii (r_eff) to cover the range anticipated from the literature: 1.6 and 1.8 μm. The resulting set of model-data comparisons, ω₀, and m are presented along with an assessment of potential sources of error and uncertainty. Analysis of the Band 1 results is limited to ω₀ as a “proof-of-concept” for our approach through a comparison to contemporaneous CRISM EPF results at 440 nm. The derived ω₀ are: assuming , and 0.765, for Bands 6, 7, and 1, respectively; for , for the same band order. For either r_eff case, the total estimated error is 0.022, 0.019, and 0.010, again for Bands 6, 7, and 1. We briefly discuss our retrievals, including the asymmetry parameter (g) associated with our model phase functions, within the context of previous efforts, with an emphasis on the improved precision of our results compared to those in the literature. We also suggest several applications of our results, including an extension of the dust climatological record using MARCI Band 7 pseudo-EPFs outside of 2007 global dust event. Initial work on this particular application using a sample of 135 pseudo-EPFs near the MERs suggests that optical depth retrievals with a precision in the range 0.2-0.4 may be possible under moderate loading conditions (i.e., τ < 1.5).  相似文献   

Lunar red spots: Possible pre-mare materials     

Michael C. Malin 《Earth and Planetary Science Letters》1974,21(4):331-341

Some anomalous red features observed on the moon by Whitaker are examined in detail. Crater counts and regional stratigraphy suggest that ages for these features are comparable to that of lunar highland material. Initial gamma-ray spectrometry indicates higher than average native radioactivity is associated with certain red areas. A possible explanation for these observations is that the red objects are the surface manifestation of highly radioactive pre-mare basalts (Apollo 14/KREEP/norite material). Conclusive proof of the nature of these objects will depend on the study of returned samples, making them ideal candidates for future space missions, especially for unmanned vehicles such as the Soviet Union's Luna 20.  相似文献   

Annual variation of the geomagnetic field     

S. R. C. Malin  D. E. Winch 《Geophysical Journal International》1996,124(1):170-174

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Mars landscape evolution: influence of stratigraphy on geomorphology in the north polar region     

Kenneth S. Edgett  Rebecca M. E. Williams  Michael C. Malin  Bruce A. Cantor  Peter C. Thomas 《Geomorphology》2003,52(3-4):289-297

Lithology and physical properties of strata exposed at the Earth's surface have direct influence on the erosion and geomorphic expression of landforms. While this is well known on our planet, examples on Mars are just coming to light among the tens of thousands of airphoto-quality images (resolutions 1.5–12 m/pixel) acquired since 1997 by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC). Specific examples occur among martian north polar layered materials, which MOC images reveal are divided into two distinct stratigraphic units: a lower, dark-toned layered unit and a younger, upper, lighter-toned layered unit. The lower unit is less resistant to wind erosion than the upper unit. The upper unit most likely consists of stratified dust and ice, while the lower unit contains abundant, poorly cemented sand. Sand is more easily mobilized by wind than dust; the lower resistance to erosion of the lower unit results from the presence of sand. Where wind erosion in polar troughs has penetrated to the lower unit, geomorphic change has proceeded more rapidly: sand has been liberated from the lower unit, and arcuate scarps have formed as the upper unit has been undermined. Wind erosion of the lower unit thus influences the geomorphology of the north polar region; this result likely explains the genesis of the large polar trough, Chasma Boreale, and the relations between dunes and arcuate scarps that have puzzled investigators for nearly three decades. The properties of the stratigraphic units suggest that the upper limit for the amount of water contained in the north polar layered materials may be 30–50% less than previously estimated.  相似文献   

World Magnetic Charts for 1980 — spherical harmonic models of the geomagnetic field and its secular variation     

F. S. Barker  D. R. Barraclough  S. R. C. Malin 《Geophysical Journal International》1981,65(2):525-533

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The Sunspot Cycle Influence on Lunar and Solar Daily Geomagnetic Variations   总被引：1，自引：0，他引：1  

S. R. C. Malin  Anna Cecere  A. Palumbo 《Geophysical Journal International》1975,41(1):115-126

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A first-order scattering solution for modelling elastic wave codas — I. The acoustic case     

P. E. Malin 《Geophysical Journal International》1980,63(2):361-380

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