Cytochrome increase

As the temperature falls, the number, volume and enzymatic capacity of mitochondria in the muscle tissues of fish increase (Jankowski and Korn, 1965 Wodtke, 1974 Johnston and Maitland, 1980 Dunn, 1988) the sizes of liver cells and their nuclei also decrease (Campbell and Davis, 1978), while the number of muscle cytochromes increases (Sidell, 1977 Demin et al, 1989). Johnston and Home (1994) have shown that the proportion of each muscle fibre occupied by mitochondria in herring larvae is greater at lower... 

T. acidophilum contains a menaquinone [123], and spectral data suggests the presence of c-type and o-type cytochromes [124]. The respiratory chain of T. acidophilum has been studied in early stationary cells in aerobic and oxygen-limited cultures. Aerobic cells contain a bands located at 554nm and 619nm, and shoulders at 559 and 549nm. The 549 nm and 554 nm bands are associated with c-type cytochromes while the 559 nm and 619 nm bands are ascribed to b and d(a2) cytochromes, respectively. In oxygen-limited cultures, the spectral features associated with the c-type cytochrome and the cytochrome oxidase decrease and those related to the b-type cytochromes increase [125]. 

Upon illumination of a mixed monolayer of chlorophyll with ferridoxine in the presence of ascorbate, Brody and Owens [22] detected a shght change in the isotherm, which in their opinion is an indication of a reaction between these components. Upon illumination of mixed films of chlorophyll and oxidized cytochrome c, a reduction in the mean area per molecule by about 18% is observed. On the other hand, illumination of films of chlorophyll with reduced cytochrome increases the area per molecule significantly (by about 10%). The difficulty of interpreting very small effects lies in the fact that in the dark the area per molecule increases both for the films with reduced cytochrome c and for the mixture containing reduced cytochrome. At any rate, for the case with reduced cytochrome c, Brody and Owens believe that they observed an electron-transfer reaction stimulated by light ... 

Cytochrome P-450 is frequently the oxygenase which detoxifies xenobiotics, including herbicides. Blocking the metaboHsm of a herbicide increases the activity or delays the inactivation, thus increasing the effectiveness of such herbicides as chlortoluron [15545-48-9] and bentazon [25057-89-0]... 

Figure 11.15 also shows that cytochrome C is displaced by lysozyme during extraction, i.e. at longer extraction times (cf. Figure 11.15(b) and (c)) the amount of lysozyme is increased as the amount of cytochrome C is decreased. 

Neurodegeneration. Figure 3 Illustration of synaptic (neuritic) apoptosis. A pyramidal neuron is depicted with cortical afferents synapsing on its dendrites. Localized apoptotic mechanisms lead to the release of cytochrome c from the mitochondria and an increase in the concentration of activated caspase-3 in a presynaptic terminal that is synapsing on a dendritic spine. Increased caspase-3 activity results in a localized breakdown of this nerve terminal and its synapse. Subsequently, the postsynaptic dendritic spine retracts and disappears (Figure modified from Glantz et al. [5] [3]). 

The process whereby cellular and tissue levels of one or more cytochrome P450 enzymes are increased in response to treatment of cells, or a whole organism,... 

Imidazole antimycotics, ketoconazole, clotrimazole, and miconazole are potent inhibitors of various cytochrome P450-isoenzymes that also affect the metabolism of retinoids. They were fust shown to inhibit the metabolism of RA in F9 embryonal carcinoma cells. When tested in vitm liarazole, a potent CYP-inhibitor, suppressed neoplastic transformation and upregulated gap junctional communication in murine and human fibroblasts, which appeared to be due to the presence of retinoids in the serum component of the cell culture medium. Furthermore, liarazole magnified the cancer chemopreventive activity of RA and (3-carotene in these experiments by inhibiting RA-catabolism as demonstrated by absence of a decrease in RA-levels in the culture medium in the presence of liarazole over 48 h, whereas without liarazole 99% of RA was catabolized. In vivo, treatment with liarazole and ketoconazole reduced the accelerated catabolism of retinoids and increased the mean plasma all-irans-RA-concentration in patients with acute promyelocytic leukemia and other cancels. 

When the second-site revertants were segregated from the original mutations, the bci complexes carrying a single mutation in the linker region of the Rieske protein had steady-state activities of 70-100% of wild-type levels and cytochrome b reduction rates that were approximately half that of the wild type. In all these mutants, the redox potential of the Rieske cluster was increased by about 70 mV compared to the wild type (51). Since the mutations are in residues that are in the flexible linker, at least 27 A away from the cluster, it is extremely unlikely that any of the mutations would have a direct effect on the redox potential of the cluster that would be observed in the water-soluble fragments. However, the mutations in the flexible linker will affect the mobility of the Rieske protein. Therefore, the effect of the mutations described is due to the interaction between the positional state of the Rieske protein and its electrochemical properties (i.e., the redox potential of the cluster). 

Evidence suggests that endosulfan can induce microsomal enzyme activity. Increased liver microsomal cytochrome P-450 activity was observed in male and female rats after single and multiple administrations of endosulfan (Siddiqui et al. 1987a Tyagi et al. 1984). Increased enzyme activity was observed in hepatic and extrahepatic tissues. Based on the increase in aminopyrine-A-demethylase and aniline hydroxylase activity, endosulfan has been shown to be a nonspecific inducer of drug metabolism (Agarwal et al. 1978). 

There is increasing evidence that microsomal monooxygenases with cytochrome P450 as their active center have a dominant role in the detoxication of the great... 

Of particular interest in the present context is that TBT can inhibit cytochrome-P450-based aromatase activity in both vertebrates and aquatic invertebrates (Morcillo et al. 2004, Oberdorster and McClellan-Green 2002). The conversion of testosterone to estradiol is catalyzed by aromatase, and so inhibition of the enzyme can, in principle, lead to an increase in cellular levels of testosterone. The significance of this is that many mollusks experience endocrine disruption when exposed to TBTs,... 

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