A LC-MS/MS-Based Approach to Studying the Saccharomyces cerevisiae Cca1 Protein

The enzyme ATP (CTP): tRNA-specific tRNA nucleotidyltransferase (tRNA-NT) is an essential enzyme in eukaryotes and some prokaryotes and plays a critical role in tRNA maturation. This enzyme is responsible for the addition of AMP and CMP residues to the 3’-ends of tRNA molecules to allow for their aminoacylation and subsequent use in protein synthesis. The tRNA-NT (Cca1) in Saccharomyces cerevisiae (yeast), although encoded by a single nuclear gene (CCA1), functions in multiple cellular compartments (cytosol, nucleus, and mitochondrion). Here we used mass spectrometry to explore both cis- and trans-acting factors that could provide clues to the importance of the function and localization of this enzyme in Saccharomyces cerevisiae. We characterized post-translational modifications on the native enzyme and analyzed the proteomes of native and temperature-sensitive (ts) yeast strains at permissive (20oC and 30oC) and quasi-restrictive (33oC) temperatures. Our experiments identified amino acids cysteine 307, lysine 312 and tyrosine 317 in one α-helix as sites of post-translational modifications in early log phase showing acetylation, acetylation and phosphorylation, respectively. As these modifications were present, this may suggest that these post-translational modifications play a role in protein function or localization. As we have identified a mutation in the gene coding for tRNA-NT that leads to a temperature-sensitive phenotype, we set out to do a comparison of the proteome profiles of this strain and the native yeast strain from which it was derived. This study revealed specific differences between the native and ts strains and between the different temperatures tested. Levels of stress-response proteins (Ctt1, Ddp1, Gad1, Prx1, Sod2, Tdh1, Uga1, and Uga2) were increased in the variant but not the native strain at 33°C but not in either the native or the variant at any other temperature tested (20°C or 30°C). This suggests that in the ts strain, the stress response is induced to combat the loss of activity associated with the variant tRNA-NT. In addition, a number of mitochondrial or ribosomal proteins such as Aim24, Atp20, Cox2, Cox5A, Mhr1, Nuc1, Rip1, Drs1, Edc3, Hca4, Nog2, Nsa2, Rlp7, Sod1, Sof1, Tsr4, Utp23 whose levels differ in the native and variant proteomes were identified, suggesting pathways to be explored to explain the ts phenotype

Optimization of Fast-Decodable Full-Rate STBC with Non-Vanishing Determinants

Full-rate STBC (space-time block codes) with non-vanishing determinants achieve the optimal diversity-multiplexing tradeoff but incur high decoding complexity. To permit fast decoding, Sezginer, Sari and Biglieri proposed an STBC structure with special QR decomposition characteristics. In this paper, we adopt a simplified form of this fast-decodable code structure and present a new way to optimize the code analytically. We show that the signal constellation topology (such as QAM, APSK, or PSK) has a critical impact on the existence of non-vanishing determinants of the full-rate STBC. In particular, we show for the first time that, in order for APSK-STBC to achieve non-vanishing determinant, an APSK constellation topology with constellation points lying on square grid and ring radius \sqrt{m^2+n^2} (m,n\emph{\emph{integers}}) needs to be used. For signal constellations with vanishing determinants, we present a methodology to analytically optimize the full-rate STBC at specific constellation dimension.Comment: Accepted by IEEE Transactions on Communication

what can we learn from the provision of childcare in rural China?

This paper explores whether the co-production model is more effective than the government-centric model in the provision of rural child welfare services in rural China. What are the processes and patterns of co-production in service provision? The paper begins by introducing the transition in the logic of service provision in the public sector from New Public Management to New Governance Theory. Then it elucidates the state of rural public service provision in China, especially child-related services. It then introduces a case that employs a co-production model in delivering child welfare services in rural China. By comparing the different intervention effects of the co-production versus the government-centric model, the paper argues that the co-production model is a dynamic way to deliver public services

Study of the Value of Soft Power of the Traditional Confucian Moral Sentiments

Western philosophy is basically holding the dichotomy of reason and emotional attitude. Rational ability than emotional, it has an innate superiority for inductive, which is originated in the way of Plato’s classic thinking. But in comparison with the rational, the perceptual is often considered as blind, spontaneous, and difficult to control and dominate. In the tradition of Western philosophy, the relationship between the emotional and rational has been unequal; the sensibility is always at a disadvantage position, even once reduced to the ability to collect empirical material. Then, is perceptual has rich content itself. What is the relationship between the emotional and moral? This problem has not meant a good answer.The crux of the problem is that the real person is a whole life. This whole life is required to cross-examine the meaning and value of life. The meaning and value of life are closely connected with emotion. Chinese traditional Confucianism especially places great importance on the emotional problems. This attention to the emotional issues of concern for man as man, that is to say, for the meaning and value of life, traditional Confucianism focus on the value and dignity of the person