Comparison of two gel filtration chromatographic methods for the purification of Lily symptomless virus

Purification of cell-derived Japanese encephalitis virus by dual-mode chromatography

Purification of the enveloped virus poses a challenge as one must retain viral infectivity to preserve immunogenicity. The traditional process of virus purification is time-consuming, laborious and hard to scale up. Here, a rapid, simple and extensible laboratory program for the purification of Japanese encephalitis virus (JEV) was developed by using differential centrifugation, ultrafiltration, Sepharose 4 fast flow gel chromatography, and Capto^TM Core 700 chromatography. The entire process recovered 61.64% of the original virus, and the purified virus particles maintained good activity and immunogenicity. The purification process described has potential application in large-scale production of high-purity JEV.

Rapid visual detection of lily mottle virus using a loop-mediated isothermal amplification method

Lily mottle virus (LMoV; genus Potyvirus, family Potyviridae) infects plants of the genus Lilium, causing a reduction in flower and bulb quality. A rapid and sensitive loop-mediated isothermal amplification (LAMP) assay was developed to detect the coat protein gene of LMoV. This LAMP method was highly specific for LMoV, with no cross-reaction with other lily viruses. The sensitivity of LMoV using the LAMP assay was 100 times more sensitive than that using conventional polymerase chain reaction. A reverse transcription LAMP (RT-LAMP) was then successfully applied to detect LMoV RNA. The newly established LAMP and one-step RT-LAMP provide an alternative method for detecting LMoV in lily plants.

Simultaneous detection of three lily viruses using Triplex IC-RT-PCR

Viruses commonly infecting lily (Lilium spp.) include: Lily symptomless virus (LSV), Cucumber mosaic virus (CMV) and Lily mottle virus (LMoV). These viruses usually co-infect lilies causing severe economic losses in terms of quantity and quality of flower and bulb production around the world. Reliable and precise detection systems need to be developed for virus identification. We describe the development of a triplex immunocapture (IC) reverse transcription (RT) polymerase chain reaction (PCR) assay for the simultaneous detection of LSV, CMV and LMoV. The triplex IC-RT-PCR was compared with a quadruplex RT-PCR assay. Relative to the quadruplex RT-PCR, the specificity of the triplex IC-RT-PCR system for LSV, CMV and LMoV was 100% for field samples. The sensitivity of the triplex IC-RT-PCR system was 99.4%, 81.4% and 98.7% for LSV, CMV and LMoV, respectively. Agreement (κ) between the results obtained from the two tests was 0.968, 0.844 and 0.984 for LSV, CMV and LMoV, respectively. This is the first report of the simultaneous detection of LSV, CMV and LMoV in a triplex IC-RT-PCR assay. In particular we believe this convenient and reliable triplex IC-RT-PCR method could be used routinely for large-scale field surveys or crop health monitoring of lily.

Purification and immuno-gold labeling of lily mottle virus from lily leaves

Lily mottle virus (LMoV) is prevalent in Lilium species worldwide causing dwarfing, flower breaking, and reduced bulb yield. In this paper, an easy to use and efficient procedure is described for purification of LMoV from lily leaves. The resulting sample is characterized by a 260/280 nm absorbance ratio of 1.20 at a concentration of 1.27 mg/ml. The procedure results in high protein purity and particle integrity as shown by UV-spectrophotometry, polyacrylamide gel electrophoresis (PAGE), Western blotting, reverse transcriptase (RT)-PCR and transmission electron microscopy (TEM) in combination with immuno-gold labeling. This is the first time that an immuno-gold labeling (IGL) assay was performed to identify a virus of lily. Purified products can be used as a source of antigen in the preparation of antibodies against LMoV and may assist in the development of a diagnostic test for LMoV and in epidemiological surveys.

Bovine papillomavirus isolation by ultracentrifugation

The bovine papillomavirus (BPV) is the etiological agent of bovine papillomatosis, which causes significant economic losses to livestock, characterized by the presence of papillomas that regress spontaneously or persist and progress to malignancy. Currently, there are 13 types of BPVs described in the literature as well as 32 putative new types. This study aimed to isolate viral particles of BPV from skin papillomas, using a novel viral isolation method. The virus types were previously identified with new primers designed. 77 cutaneous papilloma samples of 27 animals, Simmental breed, were surgically removed. The DNA was extracted and subjected to PCR using Delta-Epsilon and Xi primers. The bands were purified and sequenced. The sequences were analyzed using software and compared to the GenBank database, by BLAST tool. The viral typing showed a prevalence of BPV-2 in 81.81% of samples. It was also detected the presence of the putative new virus type BR/UEL2 in one sample. Virus isolation was performed by ultracentrifugation in a single density of cesium chloride. The method of virus isolation is less laborious than those previously described, allowing the isolation of complete virus particles of BPV-2.

Identification of plant viruses using one-dimensional gel electrophoresis and peptide mass fingerprints

A generic assay to detect and partially characterize unknown viruses from plants was developed. Proteins extracted from virus-infected and uninfected plants were separated in one dimension by SDS polyacrylamide gel electrophoresis. Differentially expressed protein bands were eluted after trypsin digestion and resulting peptide fragments separated according to their mass by matrix-assisted laser-desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. Resulting peptide mass fingerprints (PMF) were compared with those in protein databases. The assay was used to identify three known viruses: the potyviruses Zucchini yellow mosaic virus and Turnip mosaic virus, and an alfamovirus Alfalfa mosaic virus. It was also used to identify a virus that manifested symptoms in wild Cakile maritima plants, tentatively identified as Pelargonium zonate spot virus (PZSV) (genus Anulavirus) by its PMF, and then confirmed by nucleotide sequencing. The detection of PZSV constitutes a first record of this virus in Australia and in this host. It is proposed that this rapid and simple assay is a useful approach for analysis of plant samples known to harbor viruses that could not be identified using antisera or nucleic acid-based assays.

Expression, purification and characterization of the Lily symptomless virus coat protein from Lanzhou Isolate

BACKGROUND

Lily symptomless virus (LSV) is widespread in many countries where lily are grown or planted, and causes severe economic losses in terms of quantity and quality of flower and bulb production. To study the structure-function relationship of coat protein (CP) of LSV, to investigate antigenic relationships between coat protein subunits or intact virons, and to prepare specific antibodies against LSV, substantial amounts of CP protein are needed.

RESULTS

Thus, full-length cDNA of LSV coat protein was synthesized and amplified by RT-PCR from RNA isolated from LSV Lanzhou isolate. The extended 33.6 kDa CP was cloned and expressed prokaryoticly and then purified by Ni-ion affinity chromatography. Its identity and antigenicity of recombinant CP were identified on Western-blotting by using the prepared anti-LSV antibodies.

CONCLUSIONS

The results indicate that fusion CP maintains its native antigenicity and specificity, providing a good source of antigen in preparation of LSV related antibodies. Detailed structural analysis of a pure recombinant CP should allow a better understanding of its role in cell attachment and LSV tropism. This investigation to LSV should provide some specific antibodies and aid to development a detection system for LSV diagnostics and epidemiologic surveys.

High-titer preparation of Bombyx mori nucleopolyhedrovirus (BmNPV) displaying recombinant protein in silkworm larvae by size exclusion chromatography and its characterization

Background

Budded baculoviruses are utilized for vaccine, the production of antibody and functional analysis of transmembrane proteins. In this study, we tried to produce and purify the recombinant Bombyx mori nucleopolyhedrovirus (rBmNPV-hPRR) that displayed human (pro)renin receptor (hPRR) connected with FLAG peptide sequence on its own surface. These particles were used for further binding analysis of hPRR to human prorenin. The rBmNPV-hPRR was produced in silkworm larvae and purified from its hemolymph using size exclusion chromatography (SEC).

Results

A rapid method of BmNPV titer determination in hemolymph was performed using quantitative real-time PCR (Q-PCR). A correlation coefficient of BmNPV determination between end-point dilution and Q-PCR methods was found to be 0.99. rBmNPV-hPRR bacmid-injected silkworm larvae produced recombinant baculovirus of 1.31 × 10⁸ plaque forming unit (pfu) in hemolymph, which was 2.8 × 10⁴ times higher than transfection solution in Bm5 cells. Its purification yield by Sephacryl S-1000 SF column chromatography was 264 fold from larval hemolymph at 4 days post-injection (p.i.), but 35 or 39 fold at 4.5 or 5 days p.i., respectively. Protein patterns of rBmNPV-hPRR purified at 4 and 5 days were the same and ratio of envelope proteins (76, 45 and 35 kDa) to VP39, one of nucleocapsid proteins, increased at 5 days p.i. hPRR was detected in only purified rBmNPV-hPRR at 5 days p.i..

Conclusion

The successful purification of rBmNPV-hPRR indicates that baculovirus production using silkworm larvae and its purification from hemolymph by Sephacryl S-1000 SF column chromatography can provide an economical approach in obtaining the purified BmNPV stocks with high titer for large-scale production of hPRR. Also, it can be utilized for further binding analysis and screening of inhibitors of hPRR.