Alcohol-inducible cytochrome P-450 (P-450 ALC )

Of the family of P-450 cytochromes occurring in rabbit liver microsomes, only isozyme 3 a (P-450 ALC ) is induced by alcohol administration and is effective in catalyzing the reaction: ethanol+0 2 +NADPH+H + → acetaldehyde +2H 2 O+NADP + . As judged by immuno-chemical quantitation, P-450 ALC is also induced in the animals by other diverse agents, including imidazole, trichlorethylene, acetone, pyrazole, and isoniazid. Evidence has been obtained for the occurrence of a protein immuno-chemically related to P-450 ALC in human liver microsomes and of a similar alcohol-inducible protein in the rat and in the normal and alcohol dehydrogenase-deficient deer-mouse. P-450 ALC catalyzes the activation of foreign compounds such as acetaminophen, various nitrosamines, and carbon tetrachloride and is therefore believed to play an important role in the enhanced toxicity of these substances accompanying alcohol administrationPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46156/1/204_2004_Article_BF00296940.pd

Role of alcohol P-450-oxygenase (APO) in microsomal ethanol oxidation

The form of liver microsomal cytochrome P-450 induced by chronic administration of ethanol to rabbits, designated as P-450 or P-450 isozyme 3a, has been purified to homogeneity as judged by several criteria, including NH2- and COOH-terminal amino acid sequence determination. The reconstituted alcohol-P-450 oxygenase (APO) system containing P-450 and NADPH-cytochrome P-450 reductase catalyzes the oxidation of a variety of primary and secondary alcohols to aldehydes and ketones, including methanol, ethanol, n-propanol, n-butanol, 2-butanol, n-pentanol, and cyclohexanol. Other purified P-450 cytochromes, including isozymes 2, 3b, 3c, 4, and 6, are much less active than P-450 in the oxidation of alcohols. That P-450 functions in ethanol oxidation in liver microsomal membranes as well as in the reconstituted system was shown by immunochemical experiments involving inhibition by sheep anti-P-450 antibodies. We conclude that P-450 is the predominant ethanol-oxidizing cytochrome present after induction by chronic alcohol administration and that the other P-450 cytochromes have low but significant activity in both control and ethanol-induced animals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25797/1/0000359.pd

Comparison of six rabbit liver cytochrome P-450 isozymes in formation of a reactive metabolite of acetaminophen

This laboratory has recently reported the isolation of an ethanol-inducible form of rabbit liver microsomal cytochrome P-450, designated isozyme 3a. In view of the reports of others that the hepatotoxicity of acetaminophen is increased in ethanol-treated animals and the human alcoholic, we have determined the activity of the six available P-450 isozymes in the activation of the drug to give an intermediate which forms a conjugate with reduced glutathione. Isozymes 3a, 4, and 6, all of which are present in significant amounts in the liver microsomes from rabbits chronically admini-stered ethanol, exhibited the highest activities in the reconstituted enzyme system, whereas isozymes 3b and 3c were 10- to 20-fold less effective, and phenobarbital-inducible isozyme 2 was essentially inactive, even in the presence of cytochrome 5. The results obtained thus indicate that induction by ethanol of P-450 isozyme 3a (or a homologous enzyme in other species) may contribute to the toxicity of acetaminophen but that other cytochromes also play a significant role.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25240/1/0000682.pd

Alcohol metabolism and toxicity: Role of cytochrome P-450

A new isozyme of cytochrome P-450, designated form 3a on the basis of its relative electrophoretic mobility, has been purified to homogeneity from liver microsomes of rabbits treated chronically with ethanol. This cytochrome has the highest activity of the known rabbit P-450 isozymes in the oxidation of ethanol to acetaldehyde. In view of the reports of others that the hepatotoxicity of acetaminophen is increased in ethanol-treated animals and the human alcoholic, we have determined the activity of the six available P-450 isozymes in the activation of the drug to give an intermediate which forms a conjugate with reduced glutathione. Isozymes 3a, 4, and 6, the three major forms of cytochrome P-450 present in liver microsomes from rabbits chronically treated with ethanol, exhibited the highest activities in the recostituted enzyme system, whereas isozymes 3b and 3c were 10- to 20-fold less effective and phenobarbital-inducible isozyme 2 was essentially inactive, even in the presence of cytochrome b5. The results obtained thus indicate that induction by ethanol of P-450 isozyme 3a may contribute to the toxicity of acetaminophen but that other cytochromes also play a significant role.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24851/1/0000278.pd

Identification of P-450ALC in microsomes from alcohol dehydrogenase-deficient deermice: Contribution to ethanol elimination in vivo

Isozyme 3a of rabbit hepatic cytochrome P-450, also termed P-450ALC, was previously isolated and characterized and was shown to be induced 3- to 5-fold by exposure to ethanol. In the present study, antibody against rabbit P-450ALC was used to identify a homologous protein in alcohol dehydrogenase-negative (ADH-) and -positive (ADH+) deermice, Peromyscus maniculatus. The antibody reacts with a single protein having an apparent molecular weight of 52,000 on immunoblots of hepatic microsomes from untreated and ethanol-treated deermice from both strains. The level of the homologous protein was about 2-fold greater in microsomes from naive ADH- than from naive ADH+ animals. Ethanol treatment induced the protein about 3-fold in the ADH+ strain and about 4-fold in the ADH- strain. The antibody to rabbit P-450ALC inhibited the microsomal metabolism of ethanol and aniline. The homologous protein, termed deermouse P-450ALC, catalyzed from 70 to 80% of the oxidation of ethanol and about 90% of the hydroxylation of aniline by microsomes from both strains after ethanol treatment. The antibody-inhibited portion of the microsomal activities, which are attributable to the P-450ALC homolog, increased about 3-fold upon ethanol treatment in the ADH+ strain and about 4-fold in the ADH- strain, in excellent agreement with the results from immunoblots. The total microsomal P-450 content and the rate of ethanol oxidation were induced 1.4-fold and 2.2-fold, respectively, by ethanol in the ADH+ strain and 1.9-fold and 3.3-fold, respectively, in the ADH- strain. Thus, the total microsomal P-450 content and ethanol oxidation underestimate the induction of the P-450ALC homolog in both strains. A comparison of the rates of microsomal ethanol oxidation in vitro with rates of ethanol elimination in vivo indicates that deermouse P-450ALC could account optimally for 3 and 8% of total ethanol elimination in naive ADH+ and ADH- strains, respectively. After chronic ethanol treatment, P-450ALC could account maximally for 8% of the total ethanol elimination in the ADH+ strain and 22% in the ADH- strain. Further, cytochrome P-450ALC appears to be responsible for about one-half of the increase in the rate of ethanol elimination in vivo after chronic treatment with ethanol. These results indicate that the contribution of P-450ALC to ethanol oxidation in the deermouse is relatively small. Desferrioxamine had no effect on rates of ethanol uptake by perfused livers from ADH-negative deermice, indicating that ethanol oxidation by a hydroxyl radical-mediated mechanism was not involved in ethanol metabolism in this mutant. Peroxisomal [beta]-oxidation capacity was increased 40% over control values by ethanol treatment, consistent with the hypothesis that the increase in ethanol elimination in the ADH-negative deermouse is mediated predominantly via catalase-H2O2.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27237/1/0000244.pd

Use of traditional knowledge by the United States Bureau of Ocean Energy Management to support resource management

Professionals who collect and use traditional knowledge to support resource management decisions often are preoccupied with concerns over how and if traditional knowledge should be integrated with science. To move beyond the integration dilemma, we treat traditional knowledge and science as distinct and complementary knowledge systems. We focus on applying traditional knowledge within the decision-making process. We present succinct examples of how the Bureau of Ocean Energy Management has used traditional knowledge in decision making in the North Slope Borough, Alaska: 1) using traditional knowledge in designing, planning, and conducting scientific research; 2) applying information from both knowledge systems at the earliest opportunity in the process; 3) using traditional knowledge in environmental impacts assessment; 4) consulting with indigenous leaders at key decision points; and 5) applying traditional knowledge at a programmatic decision level. Clearly articulating, early in the process, how best to use traditional knowledge and science can allow for more complete and inclusive use of available and pertinent information

Ethanol Oxidation and Toxicity: Role of Alcohol P-450 Oxygenase

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66172/1/j.1530-0277.1986.tb05179.x.pd

User participation in urban green commons : exploring the links between access, voluntarism, biodiversity and well being

Polycentric governance and stakeholder participation in natural resource management have potential benefits for both human and environmental well-being. Researchers and decision-makers have attempted to conceptualise the ecological, social and political potential of such semi-formal approaches to urban green space management. However, few studies have quantified the actual benefits in terms of biodiversity and associated ecosystem service provision, or the factors that mediate levels of participation. The links between biodiversity potential, site access and user participation were explored in a case study comprising ten established examples of organised social-ecological initiatives in the inner-city area of Greater Manchester. At the micro-scale, the case study quantified the levels of community involvement (measured in volunteer hours month¯¹) in local green commons and the biodiversity potential (assessed using floristic and structural diversity as a surrogate) of the ten sites. Descriptive analysis identified that site spatial and design characteristics affected all three measures and subsequent correlational analyses revealed a high degree of synergy between site use and biodiversity. The study thereby provides quantitative evidence of the synergistic relationship between green space use and urban biodiversity and, importantly, the positive feedbacks which should result between volunteer input and the local generation of ecosystem services. The study provides support for the promotion of a highly decentralised, stakeholder-led stewardship of green space as a valid consideration in the management of urban ecosystem services

Genome-Wide Analyses of Exonic Copy Number Variants in a Family-Based Study Point to Novel Autism Susceptibility Genes

The genetics underlying the autism spectrum disorders (ASDs) is complex and remains poorly understood. Previous work has demonstrated an important role for structural variation in a subset of cases, but has lacked the resolution necessary to move beyond detection of large regions of potential interest to identification of individual genes. To pinpoint genes likely to contribute to ASD etiology, we performed high density genotyping in 912 multiplex families from the Autism Genetics Resource Exchange (AGRE) collection and contrasted results to those obtained for 1,488 healthy controls. Through prioritization of exonic deletions (eDels), exonic duplications (eDups), and whole gene duplication events (gDups), we identified more than 150 loci harboring rare variants in multiple unrelated probands, but no controls. Importantly, 27 of these were confirmed on examination of an independent replication cohort comprised of 859 cases and an additional 1,051 controls. Rare variants at known loci, including exonic deletions at NRXN1 and whole gene duplications encompassing UBE3A and several other genes in the 15q11–q13 region, were observed in the course of these analyses. Strong support was likewise observed for previously unreported genes such as BZRAP1, an adaptor molecule known to regulate synaptic transmission, with eDels or eDups observed in twelve unrelated cases but no controls (p = 2.3×10−5). Less is known about MDGA2, likewise observed to be case-specific (p = 1.3×10−4). But, it is notable that the encoded protein shows an unexpectedly high similarity to Contactin 4 (BLAST E-value = 3×10−39), which has also been linked to disease. That hundreds of distinct rare variants were each seen only once further highlights complexity in the ASDs and points to the continued need for larger cohorts