1373results about "Viruses/bacteriophages" patented technology

The invention discloses a preparation method and application of a universal renewable immunoaffinity magnetic bead, and belongs to the technical field of chemical detection.The preparation method comprises the steps that firstly, an engineered bacteriophage H6G5-M13 is constructed, then a polypeptide module is coupled to the engineered bacteriophage H6G5-M13, the polypeptide module comprises a part A, a part B and a part C from the N end to the C end, the part A is a target object recognition sequence located at the N end, and the part C is a target object recognition sequence located at the C end; the part B is a selectively added connecting sequence, the part C is an LPXTG substrate sequence and is located at the C end, and X refers to any amino acid; finally, the engineered bacteriophage is directionally coupled to the Ni < 2 + >-IDA magnetic bead through the action of Ni-6His, and then the universal and novel immunoaffinity magnetic bead is formed. The universal and replaceable immunoaffinity magnetic bead prepared by the method can be used for preparing a chemical detection reagent, and can also be used for capturing, releasing and sensing detection of cells and extracellular vesicles.

The present invention relates to the field of lentiviral delivery. Specifically provided are a mutated vesicular virus envelope protein and the use thereof in lentiviral vector packaging.

The invention discloses a broad-spectrum lytic bacteriophage for preventing and controlling various vibrio infections in an aquaculture environment. The invention relates to V.alginolyticus phage vBValM-R37J, which is preserved in Guangdong Microbial Culture Collection Center (GDMCC) on August 6, 2025, the address is No.100 Courtyard, Xianlie Middle Road, Xianlie District, Guangzhou City, Guangdong Province, the postcode is 510070, and the preservation number is GDMCC NO.66813-B1. The invention further discloses a method for preparing the V.alginolyticus phage vBValM-R37J strain. The bacteriophage R37J is a candidate therapeutic bacteriophage with wide host spectrum, high splitting efficiency, gene safety and environmental stability, and has the potential of being popularized and applied in aquaculture as a novel biological tool for accurately preventing and controlling various vibrio infections. A new biological resource is provided for accurate prevention and control of aquatic pathogenic bacteria, and a theoretical basis and a technical support are provided for popularization and application of a phage therapy in an actual culture system.

The invention provides a micromolecular multifunctional information peptide and application thereof, and belongs to the technical field of active peptide raw material development. The sequence of the small-molecule multifunctional information peptide is VHPYVPR, the small-molecule multifunctional information peptide can be effectively combined with a downstream receptor of EGF, the EGF function is simulated, and meanwhile the situation that use of existing cell growth factor raw materials in the field of cosmetics is limited due to the molecular weight problem is avoided. Experiments prove that the micromolecular multifunctional information peptide provided by the invention can promote the repair of skin damage phenomena such as scratches, inhibit the release of inflammatory factors, inhibit the activity of beta-galactosidase and promote the generation of I-type, III-type and XVII-type collagen, shows excellent repair, soothing and anti-aging functions, is high in permeability and has a wide application prospect.

The invention relates to the technical field of microorganisms, in particular to nocardia seriolae bacteriophage as well as a composition and application thereof. The name of the nocardia seriolae bacteriophage is RDP-NS002, the nocardia seriolae bacteriophage is preserved in the China General Microbiological Culture Collection Center on August 25, 2025, and the preservation number of the nocardia seriolae bacteriophage is CGMCC No.46674. The nocardia seriolae bacteriophage is named as RDP-NS002, and the nocardia seriolae bacteriophage is preserved in the China General Microbiological Culture Collection Center on August 25, 2025. The composition comprises the bacteriophage. The bacteriophage or the composition is prepared in the following steps: (1) preparing a product for killing nocardia seriolae; (2) preparing a product for inhibiting nocardia seriola; and (3) application in preparation of a product for preventing and / or treating fish nocardia disease caused by nocardia seriolae. The phage has the characteristics of high thermal stability, high acid-base stability and high splitting rate, has a long-acting inhibition effect, and is beneficial to prevention and treatment of nocardia seriola diseases.

The invention provides a recombinant duck enteritis virus live vector vaccine and application, and belongs to the field of genetic engineering vaccines. The duck enteritis virus vaccine for expressing the duck parvovirus VP2 gene is constructed by inserting an expression framework containing the duck parvovirus VP2 gene between a US7 gene and a US8 gene of a duck enteritis virus genome by utilizing a recombinant cloning technology. After a specific pathogen-free SPF duck is immunized by the recombinant virus vaccine strain, the SPF duck can obtain immune protection on duck parvovirus and duck enteritis virus, and the recombinant virus vaccine strain can be used for preparing duck short beak dwarf syndrome and duck plague vaccines. The recombinant duck enteritis virus vaccine provided by the invention can provide multiple protection against duck parvovirus and duck enteritis virus infection at the same time, and has a good market application prospect.

The present application relates to a virus of reverse genetic operation construction of NADC34-like PRRSV2. Specifically, the full gene sequence of NADC34-like PRRSV2 BJ1805-2 isolated strain is segmented and connected to the vector by using PCR amplification, enzyme digestion and other methods with pACY177 plasmid as the carrier, and the BJ1805-2 full-length infectious clone recombinant plasmid (rBJ1805-2) is obtained. The infectious clone virus rBJ1805-2 is rescued in vitro, and the first NADC34-like PRRSV2 strain infectious clone platform in China is successfully built. The present application also relates to a modification method for constructing NADC34-like PRRSV2 strain which can adapt to Marc-145 cell passage culture. The infectious clone virus constructed by the present application has good in vitro and in vivo proliferation efficiency, and can cause specific viremia after inoculation in pigs; it has good safety, does not cause fever after inoculation in pigs, and will not cause piglet death. The modified strain can be used as a candidate strain for developing the first NADC34-like PRRSV2 specific vaccine in China, and is conducive to the prevention and control of PRRSV epidemic in China.

The invention relates to the technical field of biomedicine, and discloses a human metapneumovirus culture method which comprises the following steps: a culture medium is prepared and put into a culture bottle, and the culture medium comprises a DMEM culture medium, glucose, sodium bicarbonate, an HEPES buffer solution, chondroitin sulfate and hyaluronic acid; host cells are selected; preparing a culture solution, wherein the culture solution comprises L-glutamine, bovine serum albumin, antibiotics and N-acetylcysteine; and inoculating the human metapneumovirus into the culture medium for adsorption and infection. The chondroitin sulfate and the hyaluronic acid are added into the culture medium, the chondroitin sulfate and the hyaluronic acid can be combined with glycosaminoglycans on the surfaces of the host cells to form a compound, interaction sites of viruses and the host cells are increased, then virus receptor expression on the surfaces of the host cells is enhanced, the cell membrane environment is optimized, and therefore the anti-tumor effect is achieved. Therefore, the attachment and entry efficiency of the hMPV is improved, and the rapid proliferation of the virus is obviously promoted.

The invention belongs to the technical field of biological control, and particularly relates to a streptomyces bacteriophage St01 and application thereof. The streptomyces bacteriophage St01 is separated from a soil environment, has the advantages of relatively good propagation performance, short outbreak period, relatively good environmental stability, good genetic stability and good safety, can specifically infect and split pathogenic streptomyces without killing other bacteria, does not cause additional influence on normal flora, and has a good application prospect. As a bacterial virus, the bacteriophage is not influenced by bacterial drug resistance, does not cause the problems of drug residues and the like in application, and has the characteristics of high safety and environmental friendliness; the bacillus subtilis can efficiently kill pathogenic streptomycete in plants and in a soil environment, and has good application prospects in killing the pathogenic streptomycete in the environment, preventing and treating pathogenic streptomycete infection and preventing and treating plant diseases caused by the pathogenic streptomycete; meanwhile, the method can also be used for detecting pathogenic streptomyces and / or identifying plant diseases caused by the pathogenic streptomyces.

The invention belongs to the technical field of gene engineering, and provides shRNA (short hairpin Ribonucleic Acid) for knocking down BST2 gene expression, a recombinant vector and application of the shRNA, and the shRNA comprises Bst2-shRNA-1 or Bst2-shRNA-2; the Bst2-shRNA-1 comprises a positive-sense strand of which the nucleotide sequence is as shown in SEQ ID NO. 1 and an antisense strand of which the nucleotide sequence is as shown in SEQ ID NO. 2; the Bst2-shRNA-2 comprises a positive-sense strand of which the nucleotide sequence is as shown in SEQ ID NO. 3 and an antisense strand of which the nucleotide sequence is as shown in SEQ ID NO. 4. The shRNA disclosed by the invention plays an important role in inhibiting non-infectious aseptic inflammation, can effectively delay the ALS attack time and protect motor neurons, has a very good application prospect, and also provides a direction and a technical basis for searching, researching and developing new therapeutic drugs for treating ALS.

The invention belongs to the technical field of biology, and discloses a recombinant turkey herpesvirus co-expressing an avian influenza H9 gene and an avian adenovirus 4 type Fiber-2 gene, the H9 gene containing a promoter and a terminator is inserted between an HVT053 site and an HVT054 site of the turkey herpesvirus, the Fiber-2 gene containing a promoter and a terminator is inserted between an HVT087 site and an HVT088 site of the turkey herpesvirus, and the recombinant turkey herpesvirus co-expressing the avian influenza H9 gene and the avian adenovirus 4 type Fiber-2 gene is obtained. The recombinant virus is obtained. The recombinant turkey herpesvirus can stably co-express the H9N2 subtype avian influenza virus H9 protein and the fowl adenovirus 4 type Fiber-2 protein, has very excellent immune performance, and effectively improves the immune effect of the recombinant virus of the traditional fowl adenovirus Fiber-2 gene; compared with the recombinant herpesvirus of turkey which singly expresses any one of the H9N2 subtype avian influenza virus H9 protein and the fowl adenovirus 4 type Fiber-2 protein, the recombinant herpesvirus of turkey has the advantage that the performance of the recombinant herpesvirus of turkey is not weakened. Meanwhile, the invention also provides application and a vaccine of the recombinant herpesvirus of turkeys.

The invention relates to the field of aquaculture, in particular to a preparation method and application of a larimichthys crocea iridovirus recombinant live vector vaccine. According to the invention, replication-deficient type 5 adenovirus is selected as a target gene expression vector, a recombinant adenovirus vector comprising main capsid protein of iridovirus is constructed, recombinant virus is obtained, and the safe and effective large yellow croaker iridovirus disease recombinant live vector vaccine is created. According to the vaccine, the larimichthys crocea is immunized in a soaking or bait feeding mode, the CPM of the larimichthys crocea immunized by the vaccine is 12.0%, and the CPM of the fish without being immunized by the vaccine is 62.0%. In addition, the RPS of the inoculated fish and the RPS of the empty carrier control group fish are 80.65% and 9.68% respectively. The method is at a leading level in the field of pseudosciaena crocea biomedicine at present, and creativity is remarkable.

The invention relates to the technical field of stem cells, in particular to a lentivirus envelope plasmid combination and application thereof, a lentivirus and a packaging method thereof and a method for transduction of hematopoietic stem cells. The invention provides an envelope plasmid combination for lentivirus packaging, which is composed of lentivirus packaging plasmids containing VSVG glycoprotein and lentivirus packaging plasmids containing BaEV glycoprotein in a ratio of 3: 7. The invention further provides a method for transduction of the hematopoietic stem cells by the lentivirus, the method is simple and convenient to operate, the long-term dryness of the hematopoietic stem cells in vitro can be maintained, efficient and stable transduction of the hematopoietic stem cells can be realized, and the transduction rate is greater than 90%. The lentivirus transduction method hematopoietic stem cells can be used for hematopoietic stem cell gene therapy hematopoietic system genetic diseases, such as severe combined immunodeficiency, beta-thalassemia and sickle cell disease, Wiskott-Aldrich syndrome and the like, and the application prospect is good.

The invention belongs to the technical field of microorganisms, and discloses a high-temperature-resistant vibrio alginolyticus bacteriophage and a composition and application thereof, the high-temperature-resistant vibrio alginolyticus bacteriophage is named as vibrio alginolyticus bacteriophage PJ644 and is preserved in China General Microbiological Culture Collection Center on August 16, 2024, the preservation address is No.3, No.1 Yard, Beichen West Road, Chaoyang District, Beijing, and the preservation number is CGMCC NO.9624. The preservation number of the strain is CGMCC (China General Microbiological Culture Collection Center) No. The bacteriophage has excellent high temperature resistance, and the bacteriophage and the bacteriophage composition not only can effectively prevent and treat various vibrio infections, but also can be used as active ingredients for preparing bacteriophage pharmaceutical preparations, aquatic feed additives, water disinfectants and aquatic product preservatives, and are used for effectively preventing and treating diseases caused by vibrio infections in aquaculture farms. The use is safe, and the problems of antibiotic residues and pathogen drug resistance caused by use of antibiotics are effectively avoided.

The invention discloses two mycobacterium bacteriophages and application thereof. The two bacteriophages both have a splitting spectrum width and efficient splitting capability, can specifically realize effective splitting of mycobacteria of five specific sequence types, and are further applied to the field of prevention and control of mycobacteria. Specifically, the bacteriophage MP2435 and the bacteriophage MP2451 not only can effectively inhibit the proliferation process of mycobacteria and block the formation of a biofilm of the mycobacteria, but also can efficiently kill the mycobacteria in a milk matrix; meanwhile, the two bacteriophages can still keep relatively high activity under the conditions that the temperature is 37-65 DEG C and the pH value is 3-12, and the bactericidal activity of the bacteriophages can be stably maintained even in acid-base, high-temperature and ultraviolet-containing extreme environments. Through the characteristics, the application scene and application range of the bacteriophage in mycobacterium prevention and control are remarkably widened, and an efficient and stable novel technical means is provided for biological prevention and control of mycobacterium.

The invention discloses a vibrio cantoniensis bacteriophage vBVcaSR45Z and an application of the vibrio cantoniensis bacteriophage The invention relates to Vibrio campbelli phage vBVcaSR45Z, which is preserved in Guangdong Microbial Culture Collection Center (GDMCC) on December 8, 2025, the address is Courtyard 100 #, Xianlie Middle Road, Xiaolian District, Guangzhou City, Guangdong Province, the postcode is 510070, and the preservation number is GDMCC NO. 67441-B1. The invention further discloses a preparation method of the Vibrio campbelli phage vBVcaSR45Z strain. The bacteriophage vBVcaSR45Z has the advantages of rapid splitting capacity, high host inhibition effect, safe genome structure and clear systematic classification status, and provides an important basis for the bacteriophage vBVcaSR45Z as a biological prevention and control factor of aquatic vibrio pathogens.

The invention relates to the technical field of molecular biology, in particular to a multichannel virus reporting system based on TAT trans-activation. The invention relates to a multichannel virus reporting system based on TAT trans-activation. The multichannel virus reporting system comprises an activated virus and a reporting cell, the activated virus is a human enterovirus A71 for expressing TAT protein; the reporter cells are cells transfected with reporter plasmids; the reporter plasmid comprises an LTR sequence and a plurality of reporter genes which are started to express by the LTR sequence. When the virus is activated to infect the reporter cell, the TAT protein carried by the virus enters the reporter cell to activate the expression of the downstream reporter gene, and the expression level of the reporter gene can reflect the virus replication condition, so that the screening or mechanism research of related antiviral drugs can be realized. According to the technical scheme, the technical problem that the flexibility, stability and high-throughput screening adaptability of a virus reporting system in the prior art are not ideal can be solved, and the virus reporting system has ideal popularization and application prospects.

The invention discloses a genetically engineered virus strain of an African swine fever virus, and in a genome of the genetically engineered virus strain, a D250R gene is an inactivated gene. The microbial preservation number of a parent strain for preparing the genetic engineering virus strain is CCTCC (China Center For Type Culture Collection) NO: V 202318, and the GenBank accession number of a genomic sequence of the strain is OQ504956.1. The invention also discloses a preparation method of the genetically engineered virus strain, a vaccine composition containing the genetically engineered virus strain, a preparation method of the vaccine composition, and application of the genetically engineered virus strain in preparation of a preparation for preventing African swine fever. The genetically engineered virus strain is good in safety and immune effectiveness, and has the potential of preparing clinically applied vaccines.

The invention relates to the technical field of biology. The invention provides a grass carp brain cell line sensitive to grass carp reovirus type II, which is preserved in China Center for Type Culture Collection on October 19, 2024, and the preservation number is CCTCC NO: C2024101. The constructed grass carp brain cell line shows remarkable stability, and stable passage is successfully achieved for 60 times. And when GCRV-II is inoculated, an atypical cytopathic effect can be presented. In addition, the grass carp brain cell line has the capability of efficiently replicating GCRV-II, and even if blind passage is carried out for three generations, generated cytotoxicity can still cause morbidity and death of the grass carp. Therefore, a stable foundation is built for deeply exploring the pathogenic mechanism of the GCRV-II, developing vaccine development, screening antiviral drugs and the like, research in related fields is promoted to further progress, and a key cell model and a research basis are provided for development of related research and prevention and control strategies of the grass carp reovirus.

The invention discloses a production process for culturing nuclear polyhedrosis virus by using an S2 or SF9 cell line. The preparation method comprises the following steps: connecting a cell-penetrating peptide C105Y with DSPE-PEG2000-Mal on the surface of a lipid nanoparticle, then preparing a lipid nanoparticle LNP-C105Y by using the DSPE-PEG2000-Mal, and entrapping nuclear polyhedrosis virus DNA to obtain DNAHcNPV LNP-C105Y; the DNAHcNPV coated LNP-C105Y is inoculated into an SF9 grassland spodoptera frugiperda cell line or an S2 fruit fly cell line to be cultured, and the nuclear polyhedrosis virus is produced. On the basis of the fall webworm nuclear polyhedrosis virus, DNAHcNPV-LNP-C105Y lipid nanoparticles are synthesized and prepared by adopting a film dispersion-extrusion method to wrap the fall webworm nuclear polyhedrosis virus, and the fall webworm nuclear polyhedrosis virus is produced by inoculating the fall webworm nuclear polyhedrosis virus to SF9 and S2 cell lines. The hyphantria cunea nuclear polyhedrosis virus production process is improved, and the defect that the hyphantria cunea nuclear polyhedrosis virus production process in the prior art cannot be separated from hyphantria cunea living body feeding is overcome.

The invention belongs to the technical field of indication viruses, and particularly relates to a method for improving mouse leukemia virus titer and / or stability. The invention provides an application of mifepristone in improving mouse leukemia virus titer and / or stability. The mifepristone is utilized to integrate the mouse leukemia virus onto the cell genome, so that the amplification of the mouse leukemia virus is completed, the infection efficiency of the mouse leukemia virus is improved, and finally the mouse leukemia virus stock solution with higher titer and better stability is obtained.

The invention provides a lentivirus for treating craniopharyngeal tubuloma as well as a preparation method, application and a corresponding pharmaceutical composition of the lentivirus. The lentivirus carries an hTERT (human telomerase reverse transcriptase) promoter and a CDC6shRNA (complementary deoxyribonucleic acid) gene. According to the invention, an hTERT promoter and a CDC6shRNA gene sequence are inserted behind an enzyme cutting site of a vector, an obtained plasmid is transferred into an expression strain, the expression strain is cultured and screened to obtain a cloned strain, and the cloned strain is shaken and packaged to obtain the hTERT-CDC6shRNA lentivirus; when the lentivirus disclosed by the invention is inoculated into a tumor body of a patient with craniopharyngeal tubuloma, the result shows that the lentivirus can effectively inhibit proliferation of craniopharyngeal tubuloma cells and can induce self apoptosis of the craniopharyngeal tubuloma cells.

The invention discloses a Newcastle disease vaccine strain with high antibody escape ability and a modification method thereof, the cell strain is preserved in China General Microbiological Culture Collection Center on January 19, 2024, the address of the preservation unit is CGMCC No.45870, No.1 yard, Beichen West Road, Chaoyang District, Beijing, and the classification name of the strain is Newcastle disease virus strain. The recombinant NDV vaccine strain has the same antigen site as the current NDV gene VII type epidemic strain and has the efficient proliferation efficiency superior to that of a classical vaccine strain La Sota, the thermal stability of the NDV vaccine strain is improved by the constructed recombinant vaccine strain, and the cost of vaccine cold-chain transportation is reduced.

The invention relates to the technical field of biological medicine, and discloses a culture medium for human metapneumovirus and application, the culture medium comprises the following components by mass: 850-920 parts of a basic culture medium; the metabolism reprogramming module is prepared from the following components in parts by weight: 0.05 to 0.15 part of 5-methyltetrahydrofolic acid, 0.3 to 0.7 part of N-acetyl-D-mannosamine and 1.0 to 3.0 parts of sodium dichloroacetate; the immune regulation and control module is prepared from 0.005 to 0.015 part of an RIG-I / MAVS pathway inhibitor; the receptor induction module is prepared from 0.5 to 1.5 parts of all-trans retinoic acid; the redox balance module is prepared from the following components in parts by weight: 0.1 to 0.5 part of pegylated superoxide dismutase and 0.002 to 0.008 part of sodium selenite. According to the method, the proportion of infectious virus particles can be remarkably increased, the generation of defective particles is reduced, meanwhile, the production cycle of host cells is prolonged, large-scale continuous culture is supported, and a high-quality and high-efficiency solution is provided for industrial production of gene therapy vectors and virus vaccines.

The invention relates to a 3 'UTR element and an application thereof. The nucleotide sequence of the 3 'UTR element contains a fragment sequence of an Rtn1 gene from a termination codon to a poly A tailing signal site of a positive-sense strand. According to the characteristics of 3 'UTR of mRNA, a fragment sequence from a termination codon to a poly A tailing signal site of a sense strand of an Rtn1 gene is selected, a 3' UTR element which is more specifically expressed in the brain relative to bGHpA is obtained, the 3 'UTR element is applied to the recombinant adeno-associated virus, exogenous genes can be better helped to translate and express in neurons, and the expression efficiency of the recombinant adeno-associated virus is improved. The expression efficiency of transgenes in the brain is improved, and the method has a wide application prospect in the fields of neural circuit tracing, gene therapy and transgenosis.

The invention relates to a method for enhancing target cell removal capacity of immune cells and application. The method comprises the following steps: recombining CD58 and TP53 genes with a granzyme B gene so as to obtain recombinant genes NFAT-GZMB-CD58 and NFAT-GZMB-TP53, and meanwhile, adding a transcription factor NFAT binding site into a regulation region of the obtained recombinant genes. Then, the two recombinant genes are directionally inserted into specific gene loci of immune cells through a gene editing technology. Expression of the two recombinant genes is regulated and controlled by an immune cell activation signal pathway, and translation products of the two recombinant genes can be delivered to target cells of immune cells through a granzyme-perforin pathway, so that the scavenging capacity of the immune cells to the target cells is enhanced, and apoptosis and escape of the target cells are inhibited. The method can be applied to the field of cell therapy.

The invention discloses a bacteriophage cocktail for preventing and treating soil-borne bacterial wilt, which comprises four strains of ralstonia solanacearum obligate lytic bacteriophages in the following (1)-(4): (1) bacteriophage LC5 with the preservation number of GDMCC NO: 65460-B1; (2) a bacteriophage GC3, the preservation number of which is GDMCC NO: 65459-B1; (3) bacteriophage YH1, the preservation number of which is GDMCCNO: 65461-B1; and (4) bacteriophage YH3, the preservation number of which is GDMCC NO: 65462-B1. Indoor related experiments show that the phage cocktail composed of the four phages GC3, LC5, YH1 and YH3 can effectively inhibit growth of tobacco ralstonia solanacearum, and the effect of the phage cocktail is better than that of a single phage; pot experiments also show that the bacterial wilt can be effectively inhibited.

The present invention discloses a strain of Riemerella anatipestifer phage PT15, a phage composition thereof and its application. The phage PT15 has a deposit number of CGMCC No. 22377 and was deposited in the China General Microbiological Culture Collection Center on April 12, 2021. The present application also provides a phage composition comprising the above-mentioned phage. The above-mentioned phage and phage composition can be used as active ingredients for the preparation of therapeutic drugs and feed additives, and are used in the prevention and treatment of duck bacterial serositis. The phage composition has the advantages of safety, high efficiency and non-toxic side effects, and can be used as an active ingredient of a new type of environmental disinfectant to effectively prevent and control the pollution of breeding environment and feeding facilities, and has good application prospects.

The invention discloses a method for quickly rescuing bovine coronavirus epidemic strains and application of the method. The bovine coronavirus SHZ isolate is subjected to efficient segmented cloning, the obtained segment and a Linker sequence are subjected to a cyclic polymerase extension reaction, and the obtained reaction product can be directly transfected to 293T cells for virus packaging without purification. Different from a traditional method, the method does not need to amplify full-length virus cDNA clone by means of bacteria and yeast, but directly obtains a sufficient amount of preliminary products through PCR, and avoids the problems of instability and low efficiency when partial sequences of a virus genome proliferate in a bacteria or yeast host. By adopting the reverse genetic system, the recombinant bovine coronavirus expressing the foreign protein is successfully rescued, a brand new technical platform is provided for dynamic visualization research of in-vivo and in-vitro replication of the virus, and an efficient and flexible tool is also provided for virology research, development of virus vector vaccines and screening of antiviral drugs.

[00121] The present invention relates to a label-free, high throughput method for determining an infectious virus titer in an aqueous sample comprising infectious virus, wherein the method comprises detecting the kinetics of morphological cell alteration, such as cell rounding, following viral infection, determining a parameter defining the curve of the morphological cell alteration as a function of time post infection and determining the infectious virus titer based on a standard curve of the infectious virus at a known infectious titer.