In the present study, we demonstrated that heat shock protein 70 (Hsp70) was present in both canine reticulocytes and mature erythrocytes, and that the canine Hsp 70 in reticulocytes was decreased along with the maturation of the cells into erythrocytes. These results suggest that the Hsp 70 in canine reticulocytes might act as a chaperone to remove unnecessary proteins during reticulocyte maturation. We also demonstrated that Hsp 70 was present in exosomes from reticulocytes during their maturation in in vitro culture. Furthermore, the concentration of Hsp 70 in reticulocyte membranes was increased in proportion to an increase of the protein in exosomes until 48 hours after the incubation of reticulocytes in vitro. At 96 hours of the incubation, however, only a trace amount of Hsp 70 was detected in the membrane, while a large amount of the protein was present in the exosomes. These results suggest that Hsp 70 in canine reticulocytes might play an important role for exosome formation in reticulocytes, resulting in the maturation of the cells.

The meq gene was thought to be only detected in Marek's disease virus serotype 1 (MDV1) including a very virulent strain, Md5, while L-meq, in which a 180-bp sequence is inserted into the meq open reading frame, is found in other strains of MDV1, such as CVI988/R6. However, both meq and L-meq were previously detected by PCR in chickens infected with MDV1, suggesting hat MDV1 may consists of at least two subpopulations, one with meq, the other with L-meq. To further analyze these subpopulations, we analyzed the time course changes in distribution of these subpopulations among T cell subsets from chickens infected with MDV1. Both meq and L-meq were detected in CD4(+) and CD8(+) T cells infected with strain Md5 or CVI988/R6. The shift in MDV subpopulations from one displaying meq to the other displaying L-meq and/or the conversion from meq to L-meq occurred mainly in the CD8(+) T cell subset from Md5- infected chickens. PCR products corresponding to L-meq rather than meq were frequently amplified from the CD8(+) T cell subset from CVI988/R6-infected chickens. These results suggest that a dominant subpopulation of MDV1 changes depending on the T cell subsets, and that L-meq is dominantly present in the CD8(+) T cells which play a role in the clearance of pathogenic agents.

Pleurotus cornucopiae (PC) mushroom with a brilliant yellow pileus is found in the field and known in Japan as Tamogi dake mushroom. The purpose of this paper is to investigate the mechanism of the antimutagenic effect of PC mushroom using both the Ames test and Comet assay. We have found a strong inhibitory effect of both aqueous and organic PC extracts on the mutagenicity elicited by benzo[a]pyrene (B[a]P). This inhibition was dose- dependent in reaction mixtures containing cytosolic and microsomal fractions (S-9) from untreated rat liver as well as in those containing S-9 from aryl hydrocarbon receptor (Au) ligand of Sudan III-treated rats. Sudan III was a potent inducer of cytochrome P450 1A (CYP1A) activity. We treated rats with Sudan III to enhance the metabolic activation of B[a]P by the S-9 fraction. To explain whether this antimutagenicity was due to the inhibition of CYP1A activity that metabolically activates B[a]P, we tested the effects of the extracts on activities of CYP1A1 and CYP1A2, represented by ethoxyresorufin Odeethylase (EROD) and methoxyresorufin Odemethylase (MROD), respectively. Both aqueous and organic extracts inhibited EROD activity at all dose levels, while the inhibitory effect was only observed at high doses with regard to MROD activity. Furthermore, pre-treatment of Chinese hamster V79cells with PC extracts significantly reduced H2O2 - induced-DNA damage, indicating that PC extracts provide a protective effect against oxidative DNA damage. These results indicate that whole-mushroom extracts contain compounds that may inhibit the metabolic activation of B[a]P by CYP1A1 as well as prevent oxidative DNA damage.

Green tea contains catechins and caffeine as major constituents. Treatment of rats with green tea (2.5% w/v) significantly increased 7-ethoxycou-marin 0-deethylase (7-ECOD), caffeine N-1 demethylase (CN1D) and UDP-glucuronyltransferase (UGT) activities. Treatment with caffeine similarly activated CYP1A2 and related monooxygenases as well as UGT, while treatment with catechins induced UGT activity but not 7- ECOD or CN1D activity. Numbers of benzo[a]pyrene (BP) -induced revertant colonies in an Ames test (mutation assay) with S. typhimurium TA98 as the test strain were markedly larger when BP was preincubated with the liver S-9 (9000 x g supernatant of liver homogenate) from green tea-treated rats than when preincubated with that from control rats. In a modified Ames assay system in which UGT was activated by the addition of UDP-glucuronic acid to the preincubation mixture, numbers of revertant colonies in the assay using liver S-9 from green tea-treated rats decreased to a similar level to that in the assay using S-9 from controls. The acceleration of two enzymatic reactions may contribute to the rapid elimination of BP; the first step, the formation of a metabolic intermediate (which is mutagenic) by CYP1A2 and the second, the conjugation of active metabolic intermediates by UGT. We speculated that green tea can reduce the amount of time carcinogens reside in the body and the chance that body tis-sues will be exposed to active metabolites of carcinogens thorough rapid elimination due to the simultaneous induction of CYP1A2 and UGT activities.