Guy Croizier

Insect lysozymes from three species of lepidoptera: Their structural relatedness to the c (chicken) type lysozyme

SummarySequence studies of the N-terminal halves of the lysozymes isolated fromBombyx mori, Galleria mellonella andSpodoptera littoralis (Lepidoptera) allow us to classify these enzymes among the c (chicken) type lysozymes.

Recombination of Autographa californica and Rachiplusia ou Nuclear Polyhedrosis Viruses in Galleria mellonella L.

Summary Cotransfection of Rachiplusia ou nuclear polyhedrosis virus (RoMNPV) and BamHI or SmaI fragments from the genome of Autographa californica nuclear polyhedrosis virus (AcMNPV) yielded a high frequency of virus recombinants in Galleria mellonella larvae. When larvae were cotransfected either with the entire genome of AcMNPV and RoMNPV restriction fragments or with a mixture of the two viruses, only AcMNPV was produced. In the virus recombinants, the prevalence of certain regions from the genome of the donor virus (AcMNPV) varied considerably, e.g. from 0% in the 35 to 41 map unit region area to a high level in the 20 to 23 map unit region. The AcMNPV polyhedrin gene was shown to be inherited preferentially.

Cricket paralysis virus and drosophila C virus: serological analysis and comparison of capsid polypeptides and host range.

Abstract Five strains of Drosophila C virus (DCV) were found to be serologically indistinguishable. By using antisera against DVC strains and cricket paralysis virus (CrPV), a relationship was shown to exist between the two viruses. All DCV strains exhibited the same polypeptide profile when analyzed on SDS-polyacrylamide gels and, while basically similar, analysis of CrPV polypeptides revealed that they were slightly larger than those of DCV. Three strains of DCV could be distinguished from each other by their pathogenicity in Drosophila melanogaster or Galleria mellonella , while only CrPV was able to multiply in Gryllus bimaculatus . Also, CrPV but not DCV, could multiply in an established cell line of Lymantria dispar .

A Comparison of Buoyant Density and Polypeptides of Drosophila P, C and A Viruses

On the basis of their buoyant densities in CsCl and their capsid polypeptides, three viruses isolated from Drosophila spp. which were originally described as serotypes, are now classified as distinct viruses. The biochemical properties of each virus suggest that it has several key features in common with the mammalian picornaviruses.

A physical map of Spodoptera littoralis B-type nuclear polyhedrosis virus genome.

SummaryA physical map for the genome ofSpodoptera littoralis (Egyptian cottonworm) nuclear polyhedrosis virus of B-type (S 1MNPV-B) [Cherry CL, Summers MD (1985) J Invertebr Pathol 46: 289–295] was prepared using the restriction endonucleasesSmaI,SfiI,NotI,ApaI,KpnI,BstEII,PstI,SacI, andHindIII. The size of the genome was estimated to 136 kbp for the Morocco isolate (S 1MNPV-M2) and to 135 kbp for the Lyon isolate (S 1MNPV-L4).HindIII-K was used as the zero-point of the map because it hybridized toEcoRI-I andBamHI-F fragment ofAutographa californica (AcMNPV) DNA, and the direction of transcription of theS 1MNPV polyhedrin gene was choosen left to right. Hybridization of sixAcMNPV cloned DNA fragments withS 1MNPV-B genome shows thatS 1MNPV-B andAcMNPV genomic structures are not aligned.

Comparative analysis of the granulin regions of the Phthorimaea operculella and Spodoptera littoralis granuloviruses.

The nucleotide sequence of two cloned restriction fragments encompassing the granulin genes from the granuloviruses of the potato tuber moth, Phthorimaea operculella, PhopGV, and the Egyptian cotton leaf worm, Spodoptera littoralis, SpliGV, have been determined.Although both viruses are able to infect the same Ph. operculella cell line, their granulins do not cluster in the same phylogenetic branches. PhopGV ganulin is closely related to Cydia pomonella GV (CpGV) and Cryptophlebia leucotreta GV (ClGV) (95.2 and 94% identity at the aminoacid level), while SpliGV granulin falls close to Trichoplusia ni GV and Xestia c-nigrum GV (91.6 and 92.0% respectively).The gene organization around the granulins reflects this clustering. Upstream the PhopGV granulin, an ORF belonging to the ME53 gene family (as ORF 124R of CpGV and 909 of ClGV) is present, while no equivalent ORF is found in this region in SpliGV. Downstream the granulin, both viruses present a gene homologous to the Autographa californica nucleopolyhedrovirus (AcMNPV) ORF 9 followed by a Protein Kinase (AcMNPV ORF10). The structure of this region seems thus conserved not only among nucleopolyhedroviruses but also in at least some granuloviruses.

NUCLEOTIDE SEQUENCE OF THE POLYHEDRIN GENE OF SPODOPTERA LITTORALIS MULTIPLE NUCLEOCAPSID NUCLEAR POLYHEDROSIS VIRUS

1286 nt portion of the 3.1 kbp HindIII-K fragment of the Spodoptera littoralis multiple nucleocapsid nuclear polyhedrosis virus (SIMNPV) DNA genome has been sequenced. The sequence contains the polyhedrin gene preceded by a highly-repeated AGATAA-rich sequence. With 249 amino acids, SIMNPV polyhedrin is the longest known polyhedrin.

Protein requirements for assembly of virus-like particles of Junonia coenia densovirus in insect cells

The coding sequences of four overlapping polypeptides starting at four different in-frame AUG codons and co-terminating at the stop codon of the cap gene of Junonia coenia densovirus (JcDNV) were inserted under the control of the p10 promoter of Autographa californica nucleopolyhedrovirus (AcMNPV) to generate AcMNPV-VP1 (four polypeptides), AcMNPV-VP2 (three polypeptides), AcMNPV-VP3 (two polypeptides), and AcMNPV-VP4 (one polypeptide) recombinant viruses. In all cases, infection of Spodoptera frugiperda cells (Sf9) by each of the four recombinant viruses resulted in the production of virus-like particles (VLPs) 22-25 nm in diameter. The VLPs produced by the three recombinants AcMNPV-VP2, AcMNPV-VP3 and AcMNPV-VP4 were abundant and contained three, two and one polypeptides, respectively. VP4, the shortest polypeptide, thus appears to be sufficient for assembly of VLPs morphologically similar to those formed with two to four polypeptides. The ratio of VPs did not appear to be critical for assembly of the particles. The polypeptide starting at the first AUG immediately downstream from the p10 promoter was always the most abundantly expressed in infected cells, regardless of the construct. In contrast, plaque-purified AcMNPV-VP1 recombinants were unstable and produced less than one-twentieth of the VLPs produced by the others. All VP transcripts started at the TAAG late motif of the p10 promoter and had a poly(A) tail 14 nt downstream of a poly(A) addition signal located 98 nucleotides downstream of the common stop codon. No significant transcription initiation inside the cap sequence of AcMNPV-VP2, AcMNPV-VP3 and AcMNPV-PV4 was observed.

Étude du phénomène de l’induction de facteurs bactériolytiques chez les lépidoptères: Inhibition de la production du lysozyme chez les larves deGalleria mellonella [Lep.: Pyralidae] par l’Actinomycine D et la Cycloheximide

RésuméL’introduction de corps étrangers dans les larves de lépidoptères entraîne une augmentation parfois considérable du taux de lysozyme dans l’hémolymphe. L’efficacité inductrice de diverses substances varie dans de larges mesures. L’action de l’Actinomycine D et de la Cycloheximide sur la production du lysozyme induit a été recherchée chez des larves deGalleria mellonella L. recevant un stimulus peu spécifique (chlorure de sodium) ou plus spécifique (Micrococcus luteus vivants). L’action de ces inhibiteurs sur la quantité de lysozyme présente dans l’hémolymphe 24 h après induction, indique que les variations du taux de l’enzyme sont sous le contrôle d’un mécanisme unique indépendant de la spécificité des stimuli inducteurs. L’augmentation du taux de lysozyme chez les larves deG. mellonella induites, fait suite à une synthèse protéique et non à la libération d’enzyme préformé.SummaryForeign bodies introduced into lepidopteran larvae induce an increase, often considerable, in amount of lysozyme in the hemolymph. The efficiency of various substances to elicit the release of lysozyme in the larvae varies to a great extent. The effect of Actinomycin D and Cycloheximide introduced in theGalleria mellonella L. larvae stimulated to produce lysozyme by injection of saline or liveMicrococcus luteus was studied. The action of these metabolic inhibitors on the quantity of lysozyme in the hemolymph, 24 h after injection of the inducers, showed that the variations of the amount of the enzyme are under the control of only one mechanism which is not affected by the nature of the inducers. The increase in lysozyme amount of the hemolymph of the inducedG. mellonella larvae is due to the protein synthesis; it does not result from the release of a preformed enzyme as it was demonstrated in other animal species.