P13 of Leucania separata multiple nuclear polyhedrosis virus affected the polyhedra and budded virions yields of AcMNPV

p13 gene was first described by our laboratory in Leucania separata multiple nuclear polyhedrovirus (Ls-p13, ORF114) back to 1995. However, the functions of Ls-P13 and its reported homologues remained unknown. In order to probe the function of Ls-P13, recombinant Autographa californica nucleopolyhedroviruses (rAcMNPVs) were constructed to express Ls-P13 in the Sf9 cells at early, late or early/late phase. Observations of microscope showed that the expression of Ls-P13 could decrease the yield of AcMNPV polyhedra in Sf9 cells, and early expressed Ls-P13 had stronger inhibition efficiency than that of the late expressed. Results of flow cytometry also indicated that Ls-P13 decreased the yield of AcMNPV polyhedra while increased those of budded virions (BVs) in Sf9 cells, but the efficacy was lost when its leucine zipper-like domain was mutated. Ls-P13 is a transmembrane protein, which was early located in the nucleus and late mainly in the cytoplasm membrane at 48 h. When its transmembrane domains were deleted, Ls-P13 distribution was dramatically diverted from cytoplasm membrane to nucleus, its corresponding efficacy on polyhedra yield was further increased while that on BVs was slightly weakened. Bioassay results indicated that Ls-P13 accelerated the larvae-killing rate. The mechanism might be that Ls-P13 increased BV yield.

[Estimate the safety of baculovirus insecticides: the history and the status Quo]

This article reviews the evaluation of security of baculovirus used as a pesticide. Since 1970s, the scholars have done a lot of experiments with kinds of baculovirus to test the security of a large number kinds of living things even our human beings. Almost all experiments proved that baculovirus is secure, but some experiments came to different conclusions. These gave rise to great debate twice when they were published, but these conclusions have been proved to be wrong with later test by other scientists or the author himself. Since 90s baculovirus have been used a great deal as the vector to express the foreign gene. Some of them reported the expression in mammalian cells, which brought the suspicious of the baculovirus safety. This article made an analysis and a conclusion about them. Also, this article laid emphasis on the security of recombination baculovirus with the results of the security experiment of self-made recombination baculovirus pesticide. In the last analysis, this article draws a conclusion that the baculovirus and recombinant baculovirus insecticides are secure.

[Construction and bioassay of secondary recombinant baculovirus with two foreign gene]

Plasmid pAcLEneo which bears neomycin gene derived by the baculovirus IE1 promotor was digested and the gene was harvested. A transfer vector pAc34DZ2 in which the polyhedrin envelope gene has been inactivated by insertion of expression cassette of PIE1/neo was constructed by inserting the neo cassette into the SacI site of plasmid pAc34DZ1. We have constructed the polyhedrin positive recombinant virus (I) vAcPhBtT which was able to express Bt truncated endotoxin gene. In order to improve the insecticide efficiency of recombinant virus (I), an anti-neomycin recombinant virus (II) vAcPhBtTPE- was obtained by second co-transfection into the Sf9 cells with pAc34DZ2 and recombinant virus (I) DNA. Southern blot and SDS-PAGE analysis indicated that the recombinant virus (II) was still able to express the 80 kD Bt truncated delta-endotoxin, but did not express the 34 kD polyhedrin envelope protein. The recombinant virus (II) without envelope released virion faster than recombinant virus (I) after alkaline lysis. Bioassay was carried out using Spodoera exigua. LC50 of the recombinant virus (II) was about half of wild type virus and LT50 reduced about two days.

Electrospray ionization mass spectra of amino acid phosphoramidates of adenosine

Amino acid phosphoramidates of adenosine were synthesized and determined by positive and negative ion electrospray ionization mass spectrometry (ESI-MS) in conjunction with tandem mass spectrometry (MS/MS). The fragmentation pathways were investigated. In the positive ion mass spectra abundant characteristic fragment ions appeared, and many complementary ions were found. In the negative ion mass spectra only a few fragment ions were observed, and most of them contained phosphoryl groups. The results show that ESI-MS is a useful tool for structural determination of amino acid phosphoramidates of nucleosides.

Mass spectra of aminoacyl adenylate pentacoordinated phosphorus compounds

Aminoacyl adenylate pentacoordinated phosphorus compounds were analyzed by field desorption (FD) and fast atom bombardment (FAB) mass spectrometries, together with the B/E linked scan technique, and their mass spectral fragmentation pathways were investigated. For the five bonds (one P-N bond, three P-O bonds and one mixed anhydride bond P-O-CO), the cleavage usually occurred more on the P-N bond, the mixed anhydride bond and the O-C bond adjacent to the P-O bond, and less on the P-O bond. Ion YH(+), corresponding to water loss from protonated 2',3'-O-isopropylidene-adenosine, was the base peak. The results reflect the structural characteristics of aminoacyl adenylate pentacoordinated phosphorus compounds. Copyright 1999 John Wiley & Sons, Ltd.