Chemistry: molecular biology and microbiology – Process of mutation – cell fusion – or genetic modification – Introduction of a polynucleotide molecule into or...
Reexamination Certificate
1999-06-30
2003-02-18
McGarry, Sean (Department: 1635)
Chemistry: molecular biology and microbiology
Process of mutation, cell fusion, or genetic modification
Introduction of a polynucleotide molecule into or...
C435S006120, C435S091100, C536S023100, C536S023720, C536S025300
Reexamination Certificate
active
06521454
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the fields of insect control using baculoviruses and control of baculoviral infections in invertebrates.
BACKGROUND OF THE INVENTION
Historically, mosquito control operations have primarily used chemical pesticides or the bacterium
Bacillus thuringiensis israelensis
(Bti) for control of larval mosquitoes. Chemical larvicides are rapidly losing market share due to safety issues and the expense of treating large aquatic habitats, where the larvae are produced. While Bti is effective and safe, it is quickly inactivated in the environment, and works poorly in polluted water habitats.
The other major biocontrol for insects is viruses, and the Baculoviridae family of viruses, commonly called baculoviruses, has been widely studied and developed commercially for certain insects. Baculoviruses are composed of large, double-stranded, circular DNA molecules that are packaged in rod-shaped capsids. The Baculoviridae includes the Nucleopolyhedroviruses and the Granuloviruses subgroups (see Granados R R and B A Federici, Eds. 1986
The Biology of Baculoviruses,
Vol. 1. Boca Raton, Fla.: CRC Press; Volkman, L E et al. 1995.
Baculoviruses.
In: Virus Taxonomy. Sixth Report of the International Committee on Taxonomy of Viruses. Murphy, F A et al. Eds Springer Verlag Wien).
Insect control using baculoviruses is an attractive approach, because baculoviruses only infect invertebrates, and they can generally be produced in sufficiently high numbers for commercial use. The viruses are produced naturally in two forms: “occluded” and “non-occluded”. The occluded form, in which the DNA genome is surrounded by crystalline proteins (forming a structure called the inclusion or occlusion body), is the form in which the virus is spread naturally from one insect to another. It is also the form that makes a good insecticide formulation, since it is stable in the environment and in commercial packaging, and it can be mixed more readily with other pesticide formulations.
Despite the many advantages of baculoviruses for insect control, one commercial disadvantage is that a single baculovirus species has a fairly narrow host range, so a given baculovirus cannot be used for broad spectrum insect control. One of the best studied baculoviruses,
Autographa californica
nuclear polyhedrosis virus (AcNPV), is considered to have a fairly broad host range for a baculovirus, since it is known to infect over thirty species of Lepidoptera. The celery looper multiple embedded virus described by Hostetter and Puttler (U.S. Pat. No. 4,911,913) also is considered to have broad insecticidal activity within the Lepidoptera.
Thus, to develop an effective baculoviral control strategy for mosquitoes, there is a need to identify a viral strain that will infect as many mosquito species as possible. The first documented report of a mosquito pathogenic virus was made in 1963 with the discovery of a “cytoplasmic polyhedrosis virus” from
Culex tarsalis
in California (Kellen et al., 1963, J. Insect Pathol. 5:98-103), but this virus was later shown to be a densonucleosis virus, from the family Parvoviridae (Federici, B A 1985, “Viral Pathogens”. IN Biological Control of Mosquitoes, H C Chapman, Ed., Bull. No. 6, American Mosquito Control Association, Inc., pp. 62-74). Additional viruses pathogenic to mosquitoes have been reported from many different mosquito hosts, primarily by researchers in the U.S., Europe and Russia (Federici, 1985; ibid.; Goettel, M S 1985 Agr. Forestry Bull. 8:41-44). The first report of a baculovirus from a mosquito host was from
Aedes sollicitans
collected in Louisiana (Clark, T B, H C Chapman, and T Fukuda, 1969, J. Invert. Pathol. 14(2);284-286). Natural infections with NPVs have been reported from about ten mosquito species representing the genera Aedes, Anopheles, Culex, Psorophora, Uranotaenia and Wyeomyia (Federici, ibid.). Such infections were identified as being NPV infections based only on electron microscopic observations of the shape and size of occlusion bodies in collected larvae and on histopathological and cytopathological observations on infected larvae (Federici and Lowe 1972 Invert. Pathol. 20:14-21; Federici, B A 1980 Virology 100: 1-9; Stiles and Paschke 1980 J. Invertebr.Pathol. 35: 58-64). The AesoNPV characterized by these researchers produces spindle-shaped occlusion bodies 5-20 microns in length. H. Chapman (1974, Ann Rev Entomol 19:33-59) characterized an NPV infection in
Culex quinquefasciatus
in which the occlusion bodies are globular and from 1-5 microns in diameter. A viral disease of
Culex tarsalis
, characterized by tetragonal inclusion bodies, was described by W. R. Kellen et al. (1963, J. Insect Pathol. 5:98-103). While this virus was lost upon culturing, Clark and Chapman concluded it was the same virus that infected
Culex salinarius
(1969, J. Invert. Pathol 13:312), a virus that did not infect
Culex peccator
or
Culex quinquefasciatus.
This area of mosquito pathology has received very little attention since these preliminary, initial reports 25-30 years ago, despite the tremendous advancements made with other insect baculoviruses for use as biopesticides and expression vectors (Adams, J R and J T McClintock, 1991, pp. 87-204 In:
Atlas of Invertebrate Viruses,
Adams and Bonami, Eds., Boca Raton: CRC Press; Possee, R D 1997, Curr. Opin. Biotechnol. 8: 569-572; and Possee, R D et al. 1997 Pestic. Sci. 51: 462-470), and no NPV has been purified or isolated from mosquitoes to allow molecular studies for unequivocal identification. A major reason for the inactivity in this area has centered on the inability to reliably transmit mosquito baculoviruses to their original and alternate hosts (Federici, 1985). There are numerous factors that can affect the infectivity of a baculovirus for an insect host, including chemical, physical and/or biological factors.
Much effort has been directed at developing methods and protocols to enhance the storage and stability of baculoviruses (usually in occluded form), for use in field applications. Factors that either reduce or enhance infectivity have been identified as components of storage mixtures, formulations, or crops on which baculoviral applications are to be made. For example, several proteins have been shown to enhance baculoviral infections. Enhancin, a metalloproteinase, has been isolated from an armyworm (
Trichoplusia ni
) granulosis virus (GV), and it can enhance the activity of baculoviruses by digesting certain peritrophic membrane proteins (Corsaro et al. 1993. In “Parasites and Pathogens of Insects”, Beckage, N E et al., Eds., Volume 2: pp. 127-145, Academic Press, San Diego; Lepore L S. et al. 1996 J. Invertebr. Pathol. 68(2): 131-140; Wang P and R R Granados 1997, Proc. Natl. Acad. Sci. USA 94(13): 6977-6982; Wang, P. et al. 1997 J. Gen. Virol. 78: 3081-3089). A virus enhancing protein has also been detected in the spheroid, spindle and virion of an entomopoxvirus (Wijonarko A and T Hukuhara 1998, J. Invertebr. Pathol. 72(1): 82-86). Chitinase has also been shown to enhance infectivity of the gypsy moth NPV (Shapiro M et al. 1987, J. Econ. Entomol. 80(6): 1113-1116). Several acids, including boric and sorbic, have been shown to enhance infectivity of lepidopterous baculoviruses (Morales L et al. 1997, Ann. Soc. Entomol. Bras. 26(1): 115-120; Shapiro M and R A Bell 1982, Ann. Entomol. Soc. Am 75(3):346-349), while tannic acids have been shown to inhibit NPV infectivity (Keating et al. 1989, J. Invertebr. Pathol. 54(2):165-174; Young et al. 1995, Biological Control 5(2): 145-150).
Studies investigating the effects of various plant constituents on the infectivity of baculoviruses found that most of these actually inhibit infectivity (Elleman C J and Entwistle P F 1985, Ann. Appl. Biol 106(1): 83-92, 93-100; Felton G W and S S Duffey 1990, J. Chem. Ecol 16(4): 1221-1236; Hoover K et al. 1998 J. Chem. Ecol. 24(2): 253-271; Keating, S T et al., 1990 J. Invertebr. Pathol. 56(3): 317-326).
In addition to the use of naturally occurring baculoviruses as insect control agents,
Becnel James J.
Cockburn Andrew
Moser Bettina
Tukuo Fukuda
Undeen Albert H.
Fado John D.
McGarry Sean
Poulos Gail E.
Silverstein M. Howard
The United States of America as represented by the Secretary of
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