Purification and characterization of two forms of 2,3,4,7,8-pentachlorodibenzofuran-inducible cytochrome P-450 in hamster

Two forms of cytochrome P-450 (P-450) from liver microsomes of hamsters treated with 2,3,4,7,8-pentachlorodibenzofuran (PenCDF), which possesses the potent acute toxicity and 3-methylcholanthrene (MC)-type inducing ability of liver microsomal monooxygenases in animals, were purified and characterized. These P-450 forms, designated as hamster P-450H and hamster P-450L, had the molecular masses of 52 and 50 kDa, respectively, and showed the absorption maximum of CO-reduced difference spectra at 446 nm. The absolute spectra of their oxidized forms indicated that hamster P-450H was in high-spin state and hamster P-450L was in low-spin state. A part of PenCDF injected into hamster was tightly bound to purified hamster P-450H at a ratio of 0.107 nmol PenCDF/nmol P-450. In a reconstituted system, both hamster P-450H and hamster P-450L showed relatively low catalytic activities for 3-hydroxylation of benzo[a]pyrene and O-deethylations of both 7-ethoxyresorufin and 7-ethoxycoumarin, while they both catalyzed la-and 2a-hydroxylations of testosterone effectively to a similar extent. Addition of cytochrome fit to a reconstituted system accelerated the formation of 7a-hydroxytestosterone 5.3-fold with hamster P-450L and 2.2-fold with hamster P-450H. In addition, hamster P-450H catalyzed estradiol 2-hydroxylation at a high rate but hamster P-450L did not. Immunochemical studies using antiserum to each P-450 form revealed that hamster P-450H and hamster P-450L differ from each other and comprise about 61 and 31% of the total P-450 in PenCDF-treated microsomes, respectively, indicating that these are PenCDF-inducible and major forms of P-450 in PenCDF-treated hamsters. Similarly to PenCDF, inducers such as MC, 3,4,5,3 ,4 -pentachlorobiphenyl, and isosafrole also preferentially induced hamster P-450H rather than hamster P-450L, but #-naphthoflavone preferentially increased hamster P-450L. Phenobarbital, pregnenolone 16c-carbonitrile and ethanol did not affect the contents of these forms at all. Analyses of NH 2 -terminal amino acid sequences demonstrated that hamster P-450H and hamster P-450L correspond to rat P-450d and rat P-450a, respectively

Accuracy management survey of nucleic acid amplification tests using inactivated SARS-CoV-2 in Hiroshima Prefecture

At the beginning of 2020, the number of laboratories performing SARS-CoV-2 testing increased with the rapid expansion of COVID-19 in Hiroshima Prefecture. Thus, it is necessary to compare and verify the validity of the test results among local laboratories. In this study, we distributed the same standard samples to laboratories that performed COVID-19 testing using the nucleic acid amplification method and confirmed the accuracy of the tests. The SARS-CoV-2 strain distributed by the National Institute of Infectious Diseases (NIID), Japan, was used for testing. As measured by RT-qPCR, a specific amount of the virus was inactivated by ethanol and dried as specimens for distribution. This study included 27 tests performed at 15 laboratories conducting or planning to conduct nucleic acid amplification tests (RT-qPCR and LAMP methods) for SARSCoV-2. The detection limit of each test method was set at the value provided by the NIID. The accuracy of the tests was examined to determine whether they met the required accuracy criteria. SARS-CoV-2 genomic RNA was reliably detected in all 27 tests. The inactivated specimens used in this study were safe to distribute and could be used as positive controls for all methods.This study was supported by a grant from the Government-Academia Collaboration of Hiroshima Prefecture and by a research grant for COVID-19 from AMED, Japan under Grant Number 20he0622011h0001(to J. T.)

REPORT ON THE FIRST MOS-1 DATA RECEIVED AT SYOWA STATION, ANTARCTICA

Data from Marine Observation Satellite 1 (MOS-1) were received starting from February 1989 at Syowa Station, Antarctica, by the newly installed Multi Purpose Satellite Data Receiving System (11m antenna). The data of more than 200 paths are to be received per year, in order to study polar atmosphere, ice sheet and sea ice using three sensors, MESSR, VTIR and MSR. 2 HDDTs were brought back to Japan; they are composed of 13 paths acquired at the beginning of the system operation. Quick look films of these data were made, and some typical scenes of MESSR, VTIR and MSR were processed at NASDA EOC. Interesting features such as a giant iceberg are found among these processed images. Some limits of practical use of MESSR depending on the gain and solar elevation angle are discussed