检索结果-南通市图书馆

ITPK1 is an InsP_(6)/ADP phosphotransferase that controls phosphate signaling in Arabidopsis.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2021年第11期14卷 1864-1880页

作者： Esther Riemer Danye Qiu Debabrata laha Robert K.Harmel Philipp Gaugler Verena Gaugler Michael Frei Mohammad-Reza Hajirezaei nargis parvin laha Lukas Krusenbaum Robin Schneider Adolfo Saiardi Dorothea Fiedler Henning J.Jessen Gabriel Schaaf Ricardo F.H.Giehl Department of Plant Nutrition Institute of Crop Science and Resource ConservationRheinische Friedrich-Wilhelms-Universitat Bonn53115 BonnGermany Department of Chemistry and Pharmacy and CIBSS-Centre for Integrative Biological Signalling Studies Albert-Ludwigs University Freiburg79104 FreiburgGermany Medical Research Council Laboratory for Molecular Cell Biology(MRC-LMCB) University College LondonLondon WC1E 6BTUK Department of Biochemistry Indian Institute of ScienceBengaluruKarnataka 560012India Leibniz-Forschungsinstitut fur Molekulare Pharmakologie 13125 BerlinGermany Department of Chemistry Humboldt Universitat zu Berlin12489 BerlinGermany Institute of Agronomy and Crop Physiology Justus-Liebig University Giessen35392 GiessenGermany Department of Physiology&Cell Biology Leibniz-lnstitute of Plant Genetics and Crop Plant Research06466 GaterslebenGermany

In plants, phosphate (Pi) homeostasis is regulated by the interaction of PHR transcription factors with stand-alone SPX proteins, which act as sensors for inositol pyrophosphates. Here, we combined different methods to obtain a comprehensive picture of how inositol (pyro)phosphate metabolism is regulated by Pi and dependent on the inositol phosphate kinase ITPK1. We found that inositol pyrophosphates are more responsive to Pi than lower inositol phosphates, a response conserved across kingdoms. With CE-ESI-MS we could separate different InsP7 isomers in Arabidopsis and rice, and identify 4/6-InsP7 and a PP-InsP4 isomer hitherto not reported in plants. We found that the inositol pyrophosphates 1/3-InsP7, 5-InsP7 and InsP8 increase severalfold in shoots after Pi resupply and that tissue-specific accumulation of inositol pyrophosphates relies on ITPK1 activities and MRP5-dependent InsP6 compartmentalization. Notably, ITPK1 is critical for Pi-dependent 5-InsP7 and InsP8 synthesis in planta and its activity regulates Pi starvation responses in a PHR-dependent manner. Furthermore, we demonstrate that ITPK1-mediated conversion of InsP6 to 5-InsP7 requires high ATP concentrations and that Arabidopsis ITPK1 has an ADP phosphotransferase activity to dephosphorylate specifically 5-InsP7 under low ATP. Collectively, our study provides deeper insights into Pi-dependent changes in nutritional and energetic states with the synthesis of regulatory inositol pyrophosphates.

关键词： diphosphoinositol pentakisphosphate kinase inositol 1,3,4-trisphosphate 5/6-kinase 1 inositol phosphates inositol pyrophosphates phosphate homeostasis phosphate signaling

Frame Length Dependency for Fundamental Frequency Extraction in Noisy Speech

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Signal and Information Processing 2024年第1期15卷 1-17页

作者： Md. Saifur Rahman Any Chowdury nargis parvin Arpita Saha Moinur Rahman Department of Information and Communication Technology Comilla University Cumilla Bangladesh Department of Computer Science and Engineering Bangladesh Army International University of Science and Technology (BAIUST) Cumilla Bangladesh Department of Information Technology University of Information Technology and Sciences (UITS) Dhaka Bangladesh

The fundamental frequency plays a significant part in understanding and perceiving the pitch of a sound. The pitch is a fundamental attribute employed in numerous speech-related works. For fundamental frequency extraction, several algorithms have been developed which one to use relies on the signal’s characteristics and the surrounding noise. Thus, the algorithm’s noise resistance becomes more critical than ever for precise fundamental frequency estimation. Nonetheless, numerous state-of-the-art algorithms face struggles in achieving satisfying outcomes when confronted with speech recordings that are noisy with low signal-to-noise ratio (SNR) values. Also, most of the recent techniques utilize different frame lengths for pitch extraction. From this point of view, This research considers different frame lengths on male and female speech signals for fundamental frequency extraction. Also, analyze the frame length dependency on the speech signal analytically to understand which frame length is more suitable and effective for male and female speech signals specifically. For the validation of our idea, we have utilized the conventional autocorrelation function (ACF), and state-of-the-art method BaNa. This study puts out a potent idea that will work better for speech processing applications in noisy speech. From experimental results, the proposed idea represents which frame length is more appropriate for male and female speech signals in noisy environments.

关键词： Pitch Estimation Fundamental Frequency BaNa ACF Frame Length

TOM9.2 Is a Calmodulin-Binding Protein Critical for TOM Complex Assembly but Not for Mitochondrial Protein Import in Arabidopsis thaliana

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2017年第4期10卷 575-589页

作者： nargis parvin Chris Carrie Isabelle Pabst Antonia Laber Debabrata laha Melanie V. Paul Peter Geigenberger Ralf Heermann Kirsten Jung Ute C. Vothknecht Fatima Chigri Department Biology I Botany Ludwig-Maximilians-University Munich GroBhaderner Stra6e 2-4 82152 Martinsried Germany Department Biology 1 Microbiology Ludwig-Maximilians-University Munich Grobhaderner Strabe 2-4 82152 Martinsried Germany Department of Biology Center for Integrated Protein Science (Munich) Ludwig-Maximilians-University Munich 81377 Munich Germany Center for Plant Molecular Biology Plant Physiology University of Tuebingen Auf der Morgenstelle 32 72076 Tuebingen Germany present address: Plant Cell Biology IZMB University of Bonn Kirschallee 153115 Bonn Germany Present address: Center for Plant Molecular Biology Developmental Genetics University of Tubingen Auf der Morgenstelle 32 72076 Tubingen Germany

The translocon on the outer membrane of mitochondria （TOM） facilitates the import of nuclear-encoded proteins. The principal machinery of mitochondrial protein transport seems conserved in eukaryotes; however, divergence in the composition and structure of TOM components has been observed between mammals, yeast, and plants. TOM9, the plant homolog of yeast Tom22, is significantly smaller due to a truncation in the cytosolic receptor domain, and its precise function is not understood. Here we provide evidence showing that TOM9.2 from Arabidopsis thaliana is involved in the formation of mature TOM com- plex, most likely by influencing the assembly of the pore-forming subunit TOM40. Dexamethasone- induced RNAi gene silencing of TOM9.2 results in a severe reduction in the mature TOM complex, and the assembly of newly imported TOM40 into the complex is impaired. Nevertheless, mutant plants are fully viable and no obvious downstream effects of the loss of TOM complex, i.e., on mitochondrial import ca- pacity, were observed. Furthermore, we found that TOM9.2 can bind calmodulin （CAM） in vitro and that CaM impairs the assembly of TOM complex in the isolated wild-type mitochondria, suggesting a regula- tory role of TOM9.2 and a possible integration of TOM assembly into the cellular calcium signaling network.

关键词： protein import plant mitochondria TOM complex calmodulin calcium signaling

Deep Neural Network Based Spam Email Classification Using Attention Mechanisms

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Intelligent Learning Systems and Applications 2023年第4期15卷 144-164页

作者： Md. Tofael Ahmed Mariam Akter Md. Saifur Rahman Maqsudur Rahman Pintu Chandra Paul Miss. nargis parvin Almas Hossain Antar Department of Information and Communication Technology Comilla University Cumilla Bangladesh Department of Computer Science and Engineering Bangladesh Army International University of Science and Technology Cumilla Bangladesh

Spam emails pose a threat to individuals. The proliferation of spam emails daily has rendered traditional machine learning and deep learning methods for screening them ineffective and inefficient. In our research, we employ deep neural networks like RNN, LSTM, and GRU, incorporating attention mechanisms such as Bahdanua, scaled dot product (SDP), and Luong scaled dot product self-attention for spam email filtering. We evaluate our approach on various datasets, including Trec spam, Enron spam emails, SMS spam collections, and the Ling spam dataset, which constitutes a substantial custom dataset. All these datasets are publicly available. For the Enron dataset, we attain an accuracy of 99.97% using LSTM with SDP self-attention. Our custom dataset exhibits the highest accuracy of 99.01% when employing GRU with SDP self-attention. The SMS spam collection dataset yields a peak accuracy of 99.61% with LSTM and SDP attention. Using the GRU (Gated Recurrent Unit) alongside Luong and SDP (Structured Self-Attention) attention mechanisms, the peak accuracy of 99.89% in the Ling spam dataset. For the Trec spam dataset, the most accurate results are achieved using Luong attention LSTM, with an accuracy rate of 99.01%. Our performance analyses consistently indicate that employing the scaled dot product attention mechanism in conjunction with gated recurrent neural networks (GRU) delivers the most effective results. In summary, our research underscores the efficacy of employing advanced deep learning techniques and attention mechanisms for spam email filtering, with remarkable accuracy across multiple datasets. This approach presents a promising solution to the ever-growing problem of spam emails.

关键词： Spam Email Attention Mechanism Deep Neural Network Bahdanua Attention Scale Dot Product