A class of the hybrid chaotic sequences is presented. The generator of the sequences is given and realized by the digital method. The hybrid chaotic sequences exhibit good random properties that are very important for...A class of the hybrid chaotic sequences is presented. The generator of the sequences is given and realized by the digital method. The hybrid chaotic sequences exhibit good random properties that are very important for the performance of QS-CDMA system with RAKE receiver. The performance of the system is analyzed when the hybrid chaotic sequences are used as spreading codes in a QS-CDMA system with RAKE receiver and compared with those obtained for m-se-quences and logistic sequences. The results show that the hybrid chaotic sequences are a class of very promising spreading codes for QS-CDMA system.展开更多
The relationship between embB mutation of Mycobacterium tuberculosis and ethambutol （EMB） resistance of the clinical isolates of tuberculous patients in China was investigated by reversedot blot hybridization （RDBH...The relationship between embB mutation of Mycobacterium tuberculosis and ethambutol （EMB） resistance of the clinical isolates of tuberculous patients in China was investigated by reversedot blot hybridization （RDBH） in addition to evaluating the clinical value with application of PCR-RDBH technique to detect EMB resistance. In the present study, the genotypes of the 258 bp fragments of embB genes from 196 clinical isolates of M. tuberculosis were analysed with RDBH and DNA sequencing. It was demonstrated that 60 out of 91 phenotypically EMB-resistant isolates （65.9%） showed 5 types of missense mutations at codon 306 of embB gene, resulting in the replacement of the Met residue of the wild type strain with Val, Ile or Leu residues. In these mutations, the GTP mutation （38/91, 41.8% ） and the ATA mutation （16/91, 17.6% ） were the most encountered genotypes. The embB mutation at codon 306 could also be found in 69 isolates of phenotypically EMB-sensitive but resistant to other anti-tuberculous drugs, but no such gene mutation could be found in 36 strains of drug-sensitive isolates. Meanwhile, the concordance with the results of DNA sequencing fcr one wide-type probe and 5 probes for specific mutations was 100%. It was concluded that the EMB-resistance occurring in most M. tuberculosis is due to appearance of embB mutation at codon 306, and the PCR-RDBH assay was proved to be a rapid, simple and reliable method for the detection of gene mutations, which might be a good alternative for the drug-resistance screening.展开更多
The feasibility of the hybrid chaotic sequences as the spreading codes in code divided multiple access(CDMA) system is analyzed. The design and realization of the digital hybrid chaotic sequence generator by very high...The feasibility of the hybrid chaotic sequences as the spreading codes in code divided multiple access(CDMA) system is analyzed. The design and realization of the digital hybrid chaotic sequence generator by very high speed integrated circuit hardware description language(VHDL) are described. A valid hazard canceledl method is presented. Computer simulations show that the stable digital sequence waveforms can be produced. The correlations of the digital hybrid chaotic sequences are compared with those of m-sequences. The results show that the correlations of the digital hybrid chaotic sequences are almost as good as those of m-sequences. The works in this paper explored a road for the practical applications of chaos.展开更多
Single-molecule, real-time sequencing developed by Pacific BioSciences offers longer read lengths than the second-generation sequencing （SGS） technologies, making it well-suited for unsolved problems in genome, tran...Single-molecule, real-time sequencing developed by Pacific BioSciences offers longer read lengths than the second-generation sequencing （SGS） technologies, making it well-suited for unsolved problems in genome, transcriptome, and epigenetics research. The highly-contiguous de novo assemblies using PacBio sequencing can close gaps in current reference assemblies and characterize structural variation （SV） in personal genomes. With longer reads, we can sequence through extended repetitive regions and detect mutations, many of which are associated with dis- eases. Moreover, PacBio transcriptome sequencing is advantageous for the identification of gene isoforms and facilitates reliable discoveries of novel genes and novel isoforms of annotated genes, due to its ability to sequence full-length transcripts or fragments with significant lengths. Addition- ally, PacBio＇s sequencing technique provides information that is useful for the direct detection of base modifications, such as methylation. In addition to using PacBio sequencing alone, many hybrid sequencing strategies have been developed to make use of more accurate short reads in conjunction with PacBio long reads. In general, hybrid sequencing strategies are more affordable and scalable especially for small-size laboratories than using PacBio Sequencing alone. The advent of PacBio sequencing has made available much information that could not be obtained via SGS alone.展开更多
Microbiome-wide association studies(MWASs)have uncovered microbial markers linked to ecosystem traits,but the mechanisms underlying their functions can remain elusive.This is largely due to challenges in validating th...Microbiome-wide association studies(MWASs)have uncovered microbial markers linked to ecosystem traits,but the mechanisms underlying their functions can remain elusive.This is largely due to challenges in validating their in situ metabolic activities and tracing such activities to individual genomes.Here,we introduced a phylogeny-metabolism dual-directed singlecell genomics approach called fluorescence-in situ-hybridization-guided single-cell Raman-activated sorting and sequencing(FISH-scRACS-seq).It directly localizes individual cells from target taxon via an FISH probe for marker organism,profiles their in situ metabolic functions via single-cell Raman spectra,sorts cells of target taxonomy and target metabolism,and produces indexed,high-coverage,and precisely-one-cell genomes.From cyclohexane-contaminated seawater,cells representing the MWAS-derived marker taxon of g-Proteobacteria and that are actively degrading cyclohexane in situ were directly identified via FISH and Raman,respectively,then sorted and sequenced for one-cell full genomes.In such a Pseudoalteromonas fuliginea cell,we discovered a three-component cytochrome P450 system that can convert cyclohexane to cyclohexanol in vitro,representing a previously unknown group of cyclohexane-degrading enzymes and organisms.Therefore,by unveiling enzymes,pathways,genomes,and their in situ cellular functions specifically for those organisms with ecological relevance at one-cell resolution,FISH-scRACS-seq is a rational and generally applicable approach to dissecting and mining microbiota functions.展开更多
基金This project was supported by the National Defense Key Laboratory Foundation (99JS04.8.1. DZ02 24).
文摘A class of the hybrid chaotic sequences is presented. The generator of the sequences is given and realized by the digital method. The hybrid chaotic sequences exhibit good random properties that are very important for the performance of QS-CDMA system with RAKE receiver. The performance of the system is analyzed when the hybrid chaotic sequences are used as spreading codes in a QS-CDMA system with RAKE receiver and compared with those obtained for m-se-quences and logistic sequences. The results show that the hybrid chaotic sequences are a class of very promising spreading codes for QS-CDMA system.
文摘The relationship between embB mutation of Mycobacterium tuberculosis and ethambutol （EMB） resistance of the clinical isolates of tuberculous patients in China was investigated by reversedot blot hybridization （RDBH） in addition to evaluating the clinical value with application of PCR-RDBH technique to detect EMB resistance. In the present study, the genotypes of the 258 bp fragments of embB genes from 196 clinical isolates of M. tuberculosis were analysed with RDBH and DNA sequencing. It was demonstrated that 60 out of 91 phenotypically EMB-resistant isolates （65.9%） showed 5 types of missense mutations at codon 306 of embB gene, resulting in the replacement of the Met residue of the wild type strain with Val, Ile or Leu residues. In these mutations, the GTP mutation （38/91, 41.8% ） and the ATA mutation （16/91, 17.6% ） were the most encountered genotypes. The embB mutation at codon 306 could also be found in 69 isolates of phenotypically EMB-sensitive but resistant to other anti-tuberculous drugs, but no such gene mutation could be found in 36 strains of drug-sensitive isolates. Meanwhile, the concordance with the results of DNA sequencing fcr one wide-type probe and 5 probes for specific mutations was 100%. It was concluded that the EMB-resistance occurring in most M. tuberculosis is due to appearance of embB mutation at codon 306, and the PCR-RDBH assay was proved to be a rapid, simple and reliable method for the detection of gene mutations, which might be a good alternative for the drug-resistance screening.
文摘The feasibility of the hybrid chaotic sequences as the spreading codes in code divided multiple access(CDMA) system is analyzed. The design and realization of the digital hybrid chaotic sequence generator by very high speed integrated circuit hardware description language(VHDL) are described. A valid hazard canceledl method is presented. Computer simulations show that the stable digital sequence waveforms can be produced. The correlations of the digital hybrid chaotic sequences are compared with those of m-sequences. The results show that the correlations of the digital hybrid chaotic sequences are almost as good as those of m-sequences. The works in this paper explored a road for the practical applications of chaos.
基金supported by the institutional fund of the Department of Internal Medicine, University of Iowa, USA
文摘Single-molecule, real-time sequencing developed by Pacific BioSciences offers longer read lengths than the second-generation sequencing （SGS） technologies, making it well-suited for unsolved problems in genome, transcriptome, and epigenetics research. The highly-contiguous de novo assemblies using PacBio sequencing can close gaps in current reference assemblies and characterize structural variation （SV） in personal genomes. With longer reads, we can sequence through extended repetitive regions and detect mutations, many of which are associated with dis- eases. Moreover, PacBio transcriptome sequencing is advantageous for the identification of gene isoforms and facilitates reliable discoveries of novel genes and novel isoforms of annotated genes, due to its ability to sequence full-length transcripts or fragments with significant lengths. Addition- ally, PacBio＇s sequencing technique provides information that is useful for the direct detection of base modifications, such as methylation. In addition to using PacBio sequencing alone, many hybrid sequencing strategies have been developed to make use of more accurate short reads in conjunction with PacBio long reads. In general, hybrid sequencing strategies are more affordable and scalable especially for small-size laboratories than using PacBio Sequencing alone. The advent of PacBio sequencing has made available much information that could not be obtained via SGS alone.
基金supported by grants from the National Key R&D Program Young Scientists Project of China(2021YFD1900400)the Natural Science Foundation of China(32030003,32270109,32370097,42076165,and 32071266).
文摘Microbiome-wide association studies(MWASs)have uncovered microbial markers linked to ecosystem traits,but the mechanisms underlying their functions can remain elusive.This is largely due to challenges in validating their in situ metabolic activities and tracing such activities to individual genomes.Here,we introduced a phylogeny-metabolism dual-directed singlecell genomics approach called fluorescence-in situ-hybridization-guided single-cell Raman-activated sorting and sequencing(FISH-scRACS-seq).It directly localizes individual cells from target taxon via an FISH probe for marker organism,profiles their in situ metabolic functions via single-cell Raman spectra,sorts cells of target taxonomy and target metabolism,and produces indexed,high-coverage,and precisely-one-cell genomes.From cyclohexane-contaminated seawater,cells representing the MWAS-derived marker taxon of g-Proteobacteria and that are actively degrading cyclohexane in situ were directly identified via FISH and Raman,respectively,then sorted and sequenced for one-cell full genomes.In such a Pseudoalteromonas fuliginea cell,we discovered a three-component cytochrome P450 system that can convert cyclohexane to cyclohexanol in vitro,representing a previously unknown group of cyclohexane-degrading enzymes and organisms.Therefore,by unveiling enzymes,pathways,genomes,and their in situ cellular functions specifically for those organisms with ecological relevance at one-cell resolution,FISH-scRACS-seq is a rational and generally applicable approach to dissecting and mining microbiota functions.
