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The fmu gene product has been proposed to be an RNA methyltransferase [Koonin, E. V. (1994) Nucleic Acids Res. 22, 2476-2478]. Fmu has been cloned and expressed, and the encoded 47 kDa protein has been purified and characterized. The enzyme catalyzed specific methylation of C967 of unmodified 16S rRNA transcripts. A 16mer stem-loop structure containing C967 (nt 960-975) was also a good substrate for the enzyme in vitro. Methylation of C967 was confirmed by several methods including analysis of RNase T1 digests and nearest-neighbor analysis. Fmu did not catalyze methylation of transcripts of 23S rRNA. E. coli cells that contained kanr-disrupted fmu produced 16S rRNA that could be specifically methylated by Fmu in vitro at C967 but not C1407. Further, fmu disruption did not significantly alter the growth rate of E. coli in rich or minimal media. We propose renaming this ORF "rrmB" and the enzyme "RrmB" for rRNA methyltransferase.

This article aims to explore the relationship of evidentiality, subjectivity and ideology in Japanese history discourse. It probes into some evidentials and discursive practices present in the Japanese history textbook by drawing on systemic functional linguistics (SFL) and concepts of Japanese evidentiality. Through the quantitative and qualitative analyses of a corpus based on three Japanese history textbooks, namely NHT, HSWH and EWH, the article finds that NHT has a higher distribution of evidential categories per clause, which implies a more subjective stance. Such evidential categories as modal auxiliary verbs and modal nouns indicate a strong authorial voice, and other categories like the projecting clauses of verbal and mental processes and the discursive practice of historical document citation contribute to the construal of a linguistic ideology. The discursive practice of brackets is not only the expression of authorial voice, but also the reconstrual of a historical event.

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Lysophosphatidylcholine acyltransferase 3 (LPCAT3) is an important enzyme in phospholipid remodeling, a process that influences the biophysical properties of cell membranes and thus cell function. Multiple lines of evidence suggest that LPCAT3 is involved in several diseases, including atherosclerosis, non‐alcoholic steatohepatitis, and carcinoma. Thus, LPCAT3 may have potential as a therapeutic target for these diseases. In the present study, we devised an assay based on reversed‐phase HPLC to measure LPCAT3 activity, which may facilitate the identification of LPCAT3 inhibitors and activators. We found that optimal pH and temperature of recombinant human LPCAT3 are 6.0 and 30 °C, respectively. The enzyme Km values for substrates NBD‐labelled lysophosphatidylcholine and arachidonoyl CoA were 266.84 ± 3.65 and 11.03 ± 0.51 μmol·L−1, respectively, and the Vmax was 39.76 ± 1.86 pmol·min−1·U−1. Moreover, we used our new method to determine the IC50 of a known LPCAT inhibitor, TSI‐10. In conclusion, this novel assay can be used to measure the effects of compounds on LPCAT3 activity.

Methyltransferase (MeTrCd) and acetyl-coenzyme A synthase (ACSCd) are two key enzymes in the acetyl-coenzyme A synthesis pathway of the human pathogen Clostridium difficile. The pathway is absent in humans and is essential for the survival of the pathogen. MeTrCd and ACSCd were cloned, expressed in E. coli, and characterized for the first time. Structural and functional investigations of the two enzymes were performed using homology structure modeling, fluorescence spectroscopy, and steady state/pre-steady state kinetics. The conformational change and methyl transfer activity of MeTrCd were shown to be pH dependent. The kinetic studies of MeTrCd at the optimal pH 5.1 yield the parameters kcat (2.63 s(-1)), Km (17.8 μM) and kcat/Km (0.15 μM(-1) s(-1)). The active site metal cluster (A-cluster) of ACSCd, [Fe4S4][NipNid], was characterized using metal analysis, structural modeling, and UV/Vis spectra of the characteristic features of [Fe4S4] cubane. Nip, as a labile metal, can be removed by treatment with chelators, resulting in the loss of ACS activity. Three bidentate chelators (1,10-phenanthroline, 8-hydroxyquinoline, and 2,2-dipyridyl) exhibited excellent inhibition effects on ACSCd methyl group transfer and acetyl-coenzyme A synthesis activity. These inhibitory effects were further examined using antibacterial activity assays against Clostridium difficile. These results provide a new strategy to find new potential antibiotics for the treatment of CDI.

This paper attempts to make a corpus and cross-linguistic study of how the Pacific War is evaluated in US and Japanese history textbooks by drawing upon Systemic Functional Linguistics and the Appraisal System. The global pattern of evaluation in the data is such that the US history textbook gives more value to acts and things, creates an authoritative voice excluding alternative positions, and has a delicate construal for the extent of evaluation. By contrast, the Japanese history textbook displays a subjective affective stance and a flagged authorial voice strengthened by alternative positions. A detailed discourse analysis of the lexicogrammar in the Pacific War narratives of the US and Japanese history textbooks further shows different evaluation orientations for the construal of images of the United States and Japan. The US history textbook characterizes the United States as a state of military power and high morality for its military operations in the Pacific War while censuring Japan’s cruelty of attack, whereas the Japanese history textbook highlights Japan’s tenacity and voluntary acts on the battlefield while condemning the United States for its immorality of bombing.