Regulation and Induction

In a normal human population, the variation in the steady-state P450 27A1 mRNA level was reported to be 25-fold, compared with 60-fold for P450 7A1 in the same study . However, at least two polymorphisms (s 1% incidence, no dramatic effect) and 42 mutations (rare alleles, usually debilitating) are known . Truncation mutations are known , as well as splice variants . Defects in the CYP27A1 gene are associated with a condition known as cerebrotendinous xanthomatosis (CTX), a rare, autosomal recessive disorder characterized by accumulation of 

More detailed analysis of the vitamin Dj reaction has been with E. coli recombinant P450 27A1, with evidence for the following products (from vitamin D3) 25-hydroxy, 26-hydroxy, 27-hydroxy, 247 -25-dihydroxy, la,25-dihydroxy, 25, 

Apparently little specific work has been done on inhibition of this enzyme. Inhibition of this enzyme by a drug would probably be undesirable. 

In Cyp27Al mice, a dramatic increase in the level of P450 3A enzymes is seen some sterols accumulate and induce via the mouse PXR sys-tem . P450 3A4 has some side-chain hydroxylation activities toward cholesterol-derived sterols . However, elevated P450 3A4 activities were not increased in CTX , indicating a difference in the murine and human systems. Recently, Escher et a/. have reported that cholesterol 

In considering the general question of whether oxysterols (e.g., 27-hydroxycholesterol) control cholesterol homeostasis, the hypothesis is still open and the rodent data are not totally clear here. Bjorkhem has made the point that humans lacking P450 27A1 have normal circulating levels of cholesterol. 

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Dne to the donble effects on plants as plant-growth regulators and induction of plant defensive systems, chitosan and chitosan oligomer were used for plant tissue cultivation by supplement into cultivation media. The experiment was done with the addition of 10, 50, and 90 mg of chitosan glutamate per liter of the cultivation medium used for somatic anbryo-derived plantlet of carrot (Daucus carota L) it was shown that the addition of 100 mg of chitosan glutamate per liter of the medium led to a relatively high somatic embryo-derived plantlet conversion 4 weeks after fluid drilling, and this conversion was also sustained until 7 weeks (Kitto et al. 1991). 

With current research, it may be possible to determine common motifs involved in IgE regulation and induction that will prove to be beneficial in food... 

Lipogenesis is regulated at the acetyl-CoA carboxylase step by allosteric modifiers, phosphorylation/de-phosphorylation, and induction and repression of enzyme synthesis. Citrate activates the enzyme, and long-chain acyl-CoA inhibits its activity. Insulin activates acetyl-CoA carboxylase whereas glucagon and epinephrine have opposite actions. 

The screening method based on diameter of halos yielded only five strains with at least 20% more PG than wild t> e. Most attempts to enhance pectinase production have been made in filamentous fiingi, in which enzyme production is regulated by induction and catabolite repression mechanisms [8], By contrast, PG produced by marxianus is constitutive and not subject to catabolite repression [6], Failure to find greatly enhanced secretion levels is consistent with the idea of a constitutive gene that is capable of only modest further induction. PG was found in this study to be already the most prolific secreted protein of K. marxianus. 

Bonecchi R, Polentarutti N, Luini W, et al. Up-regulation of CCR1 and CCR3 and induction of chemotaxis to CC chemokines by IFN-gamma in human neutrophils. J Immunol 1999 162 474 179. 

T Helper Cell Cytokine Responses During Intestinal Nematode Infection Induction, Regulation and Effector Function... 

Among the most sensitive endpoints (on a body burden basis) are endometriosis, developmental neurobehavioural (cognitive) effects, hearing loss, developmental reproductive effects (sperm counts, female urinogenital malformations) and immuno-toxic effects, both adult and developmental. The most sensitive biochemical effects are CYP1A1/2 induction, hepatic retionid depletion, EGF-receptor down-regulation and oxidative stress. 

Regulation of programmed cell death (apoptosis) is not only important in normal cell development and homeostasis [1, 2], but also during the process of carcinogenesis [3], Apoptosis is suppressed in most cancer cells and induction of apoptosis is one cancer treatment strategy [4], There are many processes and factors that can be modulated to induce cancer cell apoptosis, such as regulation of factors involved in cell cycle arrest [5], protein kinase modulation [6], caspase family activation [7], and the balance in expression between Bcl-2 family members [8],... 

One of the strategies applied to enhance the degradation of specific PAH is to offer bacteria one or more known inducers to stimulate both selective growth of PAH degraders and induction of PAH metabolism [38, 73,132,148,182,194], However, little has been reported on the regulation of PAH metabolism by bacteria for compounds other than naphthalene. The transformation of benz[a]-anthracene was found to be inducible by salicylate [188] in a strain that has recently been identified as Sphingomonas yanoikuyae [172], but little else is known about the regulation of the metabolism for HMW PAH. 

Tumor Necrosis Factor There are two types of tumor necrosis factor TNF-a and TNF- 8. Of the two, TNF-a has been studied in more detail. TNF-a is a 157 amino acid polypeptide. It is a mediator of immune regulation, including the activation of macrophages and induction of the proliferation of T cells. Another TNF-a function is its cytotoxic effects on a number of tumor cells. Recent research, however, concentrates on its property in the stimulation of inflammation, particularly in the case of rheumatoid arthritis. Clinical trials are being conducted with drugs to block TNF-a with anti-TNF-a monoclonal antibodies. These antibodies target the excessive levels of TNF-a in the synovial fluid of joints and provide relief to sufferers of rheumatoid arthritis (Exhibit 4.10). 

Takagi M, Absalon MJ, McLure KG, Kastan MB (2005) Regulation of p53 translation and induction after DNA damage by ribosomal protein L26 and nucleolin. Cell 123 49-63 Tawfic S, Goueli SA, Olson MO, Ahmed K (1994) Androgenic regulation of phosphorylation and stability of nucleolar protein nucleolin in rat ventral prostate. Prostate 24 101-106. 

Trautmann A, Akdis M, Kleemann D, Altznauer F, Simon HU, Graeve T, NoU M, Brocker EB, Blaser K, Akdis CA T cell-mediated Fas-induced ker-atinocyte apoptosis plays a key pathogenetic role in eczematous dermatitis. J Clin Invest 2000 106 25-35. Schmidt-Weber CB, Blaser K Regulation and role of transforming growth factor-beta in immune tolerance induction and inflammation. 

KeY, Pearce K. Lake JP. Ziegler HK. Kapp JA y8 T lymphocytes regulate the induction and maintenance of oral tolerance. J Immunol 1997 158 3610-3618. 

ROS are the key signaling molecules during plant response to ozone, whereas ethylene, SA, and JA function as second messengers and regulate the induction and the spread of oxidative stress symptoms. An increased ethylene and S A production promotes ozone-induced cell death, whereas JA acts as a cell-protective component and limits ozone-induced damage. " ... 

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