71 results about "Multiple sequence alignment" patented technology

The invention discloses a method of application classification in Tor anonymous communication flow, which mainly solves the problem of acquisition of upper-layer application type information in the Tor anonymous communication flow and relates to the correlation technique, such as feature selection, sampling preprocessing and flow modeling. The method comprises the following steps of: firstly, defining a concept of a flow burst section by utilizing a data packet scheduling mechanism of Tor, and serving a volume value and a direction of the flow burst section as classification features; secondly, preprocessing a data sample based on a K-means clustering algorithm and a multiple sequence alignment algorithm, and solving the problems of over-fitting and inconsistent length of the data sample through the manners of value symbolization and gap insertion; and lastly, respectively modeling uplink Tor anonymous communication flow and downlink Tor anonymous communication flow of different applications by utilizing a Profile hidden Markov model, providing a heuristic algorithm to establish the Profile hidden Markov model quickly, during specific classification, substituting features of network flow to be classified into the Profile hidden Markov models of different applications, respectively figuring up probabilities corresponding to an uplink flow model and a downlink flow model, and deciding the upper-layer application type included by the Tor anonymous communication flow to be classified through a maximum joint probability value.

The present invention relates to a method for predicting three-dimensional structure of a protein from its sequence. Three-dimensional structure may be determined by: (a) generating a multiple sequence alignment for a candidate protein having a known sequence; (b) identifying a covariance matrix between all pairs of sequence positions in the multiple sequence alignment; (c) inverting the covariance matrix and identifying predicted evolutionary constraints using a statistical model of the candidate protein; and (d) simulating folding of an extended chain structure of the candidate protein using the predicted constraints.

The invention belongs to the biotechnology application field, and relates to simultaneous detection and genotyping of infections of 16 respiratory viruses (including FluA, FluB, sH1N1, PIV1, PIV2, PIV3, RSVA, RSVB, HRV, HMPV, HBoV, CoV NL63, CoV OC43, CoV 229E, CoV HKU1 and Adv) of nasopharyngeal extract specimens of patients of respiratory-related diseases of all levels of disease prevention and control institutions and sentinel hospitals. Specifically, nucleotide sequences of representative strains of the 16 respiratory viruses are downloaded from NCBI; through literature review and multiple sequence alignment, pathogen relatively-conservative regions are determined, and multiplex specific primers are designed. Single-tube multiplex (18 stages) PCR detection is carried out for detecting the 16 respiratory virus conservative regions, and an entire reaction takes less than 2 hours. According to the invention, a defect that genotyping cannot be carried out with conventional single-tube multiplex fluorescent qualitative PCR detections can be overcome, and defects of complicated operations, long time, and high cost of conventional chip detection methods can be overcome. With the application provided by the invention, a novel idea is provided for respiratory virus genotyping technologies. With characteristics of high specificity, high sensitivity, and high speed, powerful technological support is provided for rapid and accurate screening and genotyping of the respiratory-disease-related viruses. The invention has important significance upon the researches of respiratory-tract patient infection pathogen spectrum of out nation, and upon molecular epidemiological investigations.

The invention discloses a social network association searching method based on a graphics processing unit (GPU) multiple sequence alignment algorithm. The method comprises the following steps that: a central processing unit (CPU) performs web crawler on an individual webpage so as to extract an individual characteristic vector from a social network; the CPU filters redundant characteristic information from the individual characteristic vector so as to generate a uniform individual characteristic information vector base; a GPU calculates an individual distance matrix and a correction distance matrix of the social network according to the uniform individual characteristic information vector base; the GPU establishes a social network association route guidance tree according to the correction distance matrix; and the GPU traverses the social network association route guidance tree so as to perform the optimal association route searching. By utilizing the advantage that the GPU is suitable for processing a large amount of dense data, associated searching problems which are solved by the the multiple sequence alignment algorithm are parallelized, complex and time-consuming operations, such as formation and traversing of the matrixes and the association route guidance tree, are finished by the GPU, and the problem of long time caused by a large amount of social network data and operation complexity is solved.

The invention discloses a remote protein homology detection and fold recognition method based on a Top-n-gram, and relates to a remote protein homology detection and fold recognition method. The method is used for solving a problem that a binary spectrum cannot find out an optimal threshold and cannot distinguish difference of frequency of occurrences of amino acid in the prior protein remote homology detection and fold recognition method, and comprises the following steps: 1, operating a PSII-BLAST, inputting a tested protein sequence for multiple sequence alignment, and calculating a pseudocount of an amino acid i; 2, generating a frequency spectrum; 3, transforming the frequency spectrum into the Top-n-gram; 4, obtaining a latent semantic expression vector corresponding to the tested protein sequence; 5, inputting the latent semantic expression vector corresponding to the tested protein sequence into an SVM sorter for sorting, and obtaining a forecasting result. The protein remotehomology detection and fold recognition method based on the Top-n-gram is used in the filed of protein homology detection and fold recognition.

The invention discloses an MYB transcription inhibition factor LrMYB3 related to lycium ruthenicum anthocyanin synthesis and application thereof, and belongs to the technical field of gene engineering. According to transcriptome data of lycium ruthenicum, the MYB transcription inhibition factor LrMYB3 participating in anthocyanin synthesis is screened and cloned according to annotation results and expression quantity differences of MYB transcription factors, and belongs to a R2R3 type MYB transcription factor. Multiple sequence alignment and evolutionary tree analysis show that the transcription inhibition factor belongs to a FaMYB1-like transcription inhibition factor. QRT-PCR analysis shows that: the LrMYB3 is expressed in each tissue of the lycium ruthenicum, and the expression level is gradually increased along with ripening of the lycium ruthenicum. Subcellular localization and transcriptional activity detection experiments show that the LrMYB3 is a transcription factor which is localized in a cell nucleus and has no activation function.

The invention provides a method for detecting or auxiliarily detecting Phytophthora bacteria, relating to the technical field of biology. The method comprises the following steps: carrying out multiple sequence comparison on DNA (deoxyribonucleic acid) bar code sequences of Phytophthora bacteria, detecting specific base sites of each variety, and meanwhile, obtaining a consistency sequence, wherein the specific base sites of each variety comprise differentiated base sites and SNP (single-nucleotide polymorphism) sites; comparing the DNA bar code sequence of the bacterium to be detected with the consistency sequence, and regulating the length to obtain a positioning sequence; and comparing the positioning sequence with the specific base sites of each variety, marking the degree of similarity between the bacterium to be detected and various bases, taking the maximum value, and determining that the bacterium to be detected belongs to the variety with the maximum value. The method can identify the Phytophthora bacteria, is simple to operate, and has the advantages of high accuracy, short time consumption and favorable specificity.

The present invention relates to a method for identifying spirulina line production character quality. Said method includes the following steps: selecting four plants of Sp-1, Sp-2, Sp-3 and Sp-5 from abtuse acron spirulina line; utilizing upstream primer PF:5'-CAATACATCTTCG CCGATTT-3' and downstream primer PR: 5'-CGTATTATCGGTAGTCATCGG-3'; in PCR reaction system making reaction: 94 deg.C 5 min, 94 deg.C 30s, 58 deg.C 1 min, 72 deg.C 2 min, 30 cycles; 72 deg.C 8 min; connecting PCR product recovered and purified by DNA gel onto PMD18-T carrier to screen male clone; extracting plasmid and making enzyme incision identification, sequencing the recombinant plasmid containing target fragment; making the cpc HID operon gene sequences of above-mentioned four plants and correspondent sequence of identified spirulina plant undergo the process of multiple sequence comparison and creating phylogenetic tree so as to identify spirulina line character quality.

The invention belongs to the biology field, and particularly relates to application and a fixed-point knockout method of an EMC3 gene. Through targeted modification of the EMC3 gene by a gene editingtechnology and change of basic groups of a coding region to cause frame shift mutation of the EMC3 gene, an EMC3 gene knockout cell line is obtained. Experiments prove that by changing a nucleotide sequence of the EMC3 gene in a swine kidney cell (PK-15) to delete EMC3 protein expression, and proliferation of Japanese encephalitis virus (JEV) can be interfered significantly, so that host cells canbe effectively protected against JEV infection invasion induced death. Multiple sequence alignment analysis finds that the EMC3 gene sequence is highly conservative in pigs, people and mice. Therefore, the EMC3 gene can be used as a gene editing target for resisting Japanese encephalitis or used for developing anti-JEV drugs.

The invention discloses an optimizing evidence theory based K nearest-neighbor alpha-helix prediction method and relates to correlation techniques of mode recognition algorithms and computational biology. By means of the optimizing evidence theory based K nearest-neighbor alpha-helix prediction method, a membrane protein alpha-helix structure is accurately predicted when a protein sample with a high-resolution known structure is lacked. Multiple sliding window extraction feature vectors are fused to perform optimization by adopting a computational biology method including protein multiple sequence alignment and an OETPKNN algorithm, noise is smoothed by means of a median filtering method, then a prediction result is divided by means of a dynamic threshold method, and finally the membrane protein alpha-helix structure is obtained. By means of the optimizing evidence theory based K nearest-neighbor alpha-helix prediction method, the alpha-helix prediction accuracy is improved by higher than 20%, the tail end of an alpha-helix can be predicted, and a good effect is played on irregular alpha-helixes with the prediction length smaller than 15 amino acids.

The invention discloses an MYB transcription inhibition factor LrETC1 related to lycium ruthenicum anthocyanin synthesis and application thereof, and belongs to the technical field of gene engineering. According to the invention, the MYB transcription inhibition factor LrETC1 participating in the anthocyanin synthesis is screened and cloned, the total cDNA of the gene is 240bp, and 79 amino acids are encoded; protein sequence database analysis shows that the transcription factor belongs to R3 type MYB; and multiple sequence alignment and evolutionary tree analysis show that the transcription inhibition factor belongs to AtCPC-like transcription inhibition factors, and is a transcription factor which is located in a cell nucleus and does not have an activation function. A LrETC1 transgenic arabidopsis thaliana strain is obtained through agrobacterium tumefaciens-mediated genetic transformation, compared with a wild type, seed coats of seeds are light brown, arabidopsis thaliana seedlings are free of pigment accumulation under the stress condition of high sucrose concentration, and the expression level of related structural genes is remarkably reduced.

The invention relates to a detection method of ranavirus in water and belongs to the field of virus detection. The detection method of the ranavirus in culture water is constructed in combination witha method for enriching viruses in water and a PCR technology. A method for enriching viruses in water with a NaCl-AlCl3.6H2O precipitation method is improved, and the enrichment time is shortened. Specific PCR primers are improved, multiple sequence alignment is performed on MCP (major capsid protein) of ranavirus including giant salamander ranavirus, rana tigrina ranavirus, common midwife toad virus and type-3 ranavirus, primers are designed for conservative areas of sequences, so that false negative of detection due to sequence variation of viruses in the evolutionary process is avoided, the blank of methods for detecting ranavirus in water on the market at present is effectively filled up, and the method has great social benefits and economic benefits.