Materials and methods useful for the control of insect larvae

Details Materials and methods useful for the control of insect larvae Materials and methods useful for the control of insect larvae

2000-04-18

2003-10-21

Carlson, Karen Cochrane (Department: 1652)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Biocides; animal or insect repellents or attractants

C514S002600, C530S329000, C435S410000, C435S418000

Reexamination Certificate

active

06635265

ABSTRACT:

BACKGROUND OF THE INVENTION
Many blood-sucking pests are known to attack humans and animals. Many of these are vectors for pathogenic microorganisms which threaten human health and commercially important livestock and pets. Various species of mosquitoes transmit diseases caused by viruses and many are vectors for disease-causing nematodes and protozoa. For example, mosquitoes of the genus Anopheles transmit malaria which causes approximately 1 million deaths annually. The mosquito species
Aedes aegypti
transmits an arbovirus that causes the disease yellow fever in humans. Other arboviruses transmitted by Aedes species include those that cause dengue fever, eastern and western encephalitis, Venezuelan equine encephalitis, St. Louis encephalitis, chikungunya, oroponehe and bunyarnidera. The genus Culex, which includes the common house mosquito
C. pipiens
, is implicated in the transmission of various forms of encephalitis and filarial worms. The common house mosquito also acts as a vector for
Wuchereria banuffi
and
Brugia malayi
, which are responsible for lymphatic filariasis.
Trypanasomas cruzi
, the causative agent of Chagas' disease is transmitted by various species of blood-sucking Triatominae bugs. The tsetse fly (Glossina Spp.) acts as a vector for African trypanosomal diseases of humans and cattle. Many other diseases are transmitted by various blood-sucking pest species. Many of the blood-sucking pests are found within the order Diptera, including, for example, mosquitoes, black flies, no-see-ums (punkies), horse flies, deer flies and tsetse flies.
Various pesticides have been employed in efforts to control or eradicate populations of disease-bearing pests, such as disease-bearing blood-sucking pests. For example, DDT, a chlorinated hydrocarbon, has been used in attempts to eradicate malaria-bearing mosquitoes throughout the world. Other examples of chlorinated hydrocarbons, are BHC, lindane, chlorobenzilate, methoxychlor, and the cyclodienes (e.g., aldrin, dieldrin, chlordane, heptachlor, and endrin). The long-term stability and tendency of many of these pesticides to bioaccumulate render them particularly dangerous to the environment.
Another common class of pesticides is the organophosphates, which is perhaps the largest and most versatile class of pesticides. Organophosphates include, for example, parathion, Malathion, diazinon, naled, methyl parathion, and dichlorvos. Organophosphates are generally much more toxic than the chlorinated hydrocarbons. Their pesticidal effect is based on their ability to inhibit the enzyme cholinesterase, an essential enzyme in the functioning of the insect nervous system. However, they are also toxic to many animals, including humans.
The carbamates, a relatively new group of pesticides, include such compounds as carbamyl, methomyl, and carbofuran. These compounds are rapidly detoxified and eliminated from animal tissues. Their toxicity is thought to involve a mechanism similar to the mechanism of the organophosphates consequently they exhibit similar shortcomings, including animal toxicity.
A major problem in pest control results from the capability of many species to develop resistance. This resistance results from the selection of naturally occurring mutants possessing biochemical, physiological or behavioristic factors that confer some degree of immunity. Species of Anopheles mosquitoes have been known to develop resistance to DDT and dieldrin, the original pesticides used for house spraying. Substitute pesticides that are effective include Malathion, propoxur and fenitrothion; yet the cost of these pesticides is much greater than the cost of DDT.
Many pests, such as blood-sucking pests, require a proteinaceous meal to provide free amino acids that are necessary for egg development. The existence of oostatic hormones that inhibit digestion of the protein meal and thereby inhibit egg development has been demonstrated in various species, including house flies and mosquitoes.
In 1985, Borovsky purified an oostatic hormone 7,000-fold and disclosed that injection of a hormone preparation into the body cavity of blood imbibed mosquitoes caused inhibition of egg development and sterility (Borovsky, D. [1985
] Arch. Insect Biochem. Physiol
. 2:333-349). Following these observations, Borovsky (Borovsky, D. [1988
] Arch. Ins. Biochem. Physiol
. 7:187-210) disclosed that injection or passage of a peptide hormone preparation into mosquitoes inhibited the biosynthesis of serine esterase, trypsin-like and chymotrypsin-like enzymes in the epithelial cells of the gut, causing inefficient digestion of the blood meal and a reduction in the availability of free amino acids translocated by the hemolymph. Such amino acids are needed for the yolk protein synthesis in the fat body. When yolk protein is not synthesized yolk is not deposited in the ovaries, resulting in arrested egg development in the treated insect. It has been observed that the oostatic hormone peptides do not have an effect when inside the gut or other parts of the digestive system (Borovsky, D. [1988], supra).
In the mosquito
Aedes aegypti
, an early trypsin that is found in the midgut of newly emerged females is replaced, following the blood meal, by the late trypsin that is synthesized in a very short time; a female mosquito weighs 2 mg and produces 4 to 6 &mgr;g trypsin within several hours after the blood meal. If trypsin would continue to be synthesized at this rate, female mosquitoes would spend all their energy on trypsin biosynthesis and would neither be able to mature their eggs nor find an oviposition site. To conserve energy the mosquito regulates trypsin biosynthesis with a hormone named Trypsin Modulating Oostatic Factor (TMOF). TMOF is synthesized in the follicular epithelium of the ovary 2-30 hours after a blood meal and is released in to the hemolymph, binding to a specific receptor on the midgut epithelial cells signaling the termination of trypsin biosynthesis. Mosquito larvae also synthesize trypsin as their major protease and use the enzyme to digest decaying organic material or small organisms like algae that are found in ponds and marshes.
Following the initial report by Borovsky in 1985, the isolated 10 amino acid hormone, trypsin modulating oostatic factor (TMOF) was isolated. TMOF (YDPAP
6
) (SEQ ID NO. 8) and two analogs (DYPAP
6
and PAP
6
) (SEQ ID NOs. 9 and 10) of that peptide, were disclosed in U.S. Pat. Nos. 5,011,909 and 5,130,253, and in a 1990 publication (Borovsky, D., D. A. Carlson, P. R. Griffin, J. Shabanowitz, D. F. Hunt [1990
] FASEB J
. 4:3015-3020).
U.S. Pat. No. 5,358,934 discloses truncated forms of the full length TMOF which have prolines removed from the C terminus, including the peptides YDPAP (SEQ ID NO. 11), YDPAPP (SEQ ID NO. 12), YDPAPPP (SEQ ID NO. 13), and YDPAPPPP (SEQ ID NO. 14).
Neuropeptides Y (NPY) are an abundant family of peptides that are widely distributed in the central nervous system of vertebrates. In invertebrates members of NPY family have been recently isolated and their structures have been determined in a cestode and a turbellarian, respectively (Maule et al., 1991 “Neuropeptide F: A Novel Parasitic Flatworm Regulatory Peptide from
Moniezia expansa
(Cestoda: Cyclophylidea)” Parasitology 102:309-316; Curry et al., 1992 “Neuropeptide F: Primary Structure from the Turbellarian,
Arthioposthia triangulata
” Comp. Biochem. Physiol. 101C:269-274) and in terrestrial and marine molluscs (Leung et al., 1992 “The Primary Structure of Neuropeptide F (NPF) from the Garden Snail,
Helix aspersa
” Regul. Pep. 41:71-81; Rajpara et al., 1992 “Identification and Molecular Cloning of Neuropeptide Y Homolog that Produces Prolonged Inhibition in aplysia Neurons” Neuron. 9:505-513). The invertebrate NPYs exhibit high homology to vertebrate NPYs at the carboxyl terminus. The major difference between vertebrate and invertebrate NPYs at the C-terminus is that the vertebrate NPY has an amidated tyrosine (Y) whereas invertebrates have an amidated phenyl alanine (F). Because of this dif

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