Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Carbohydrate doai
Reexamination Certificate
2000-07-24
2003-07-08
Wilson, James O. (Department: 1623)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Carbohydrate doai
C504S118000, C504S292000, C536S056000
Reexamination Certificate
active
06589942
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to agricultural compositions for delivering metals to plants and for controlling microbial diseases in plants. Specifically, the present invention relates to metals chelated with a particular carbohydrate-derived composition and to methods for its use in delivering metals to agricultural crops and in controlling microbial damage to agricultural crops.
BACKGROUND OF THE INVENTION
Historically, microbiological infestations have caused significant losses to agricultural crops and have been the cause of large scale famines and economic displacements. Fungal infections can cause pre-harvest damage to crops by killing them outright or by weakening them so as to decrease yields and render the plants susceptible to other infections. Post-harvest, fungal infections can also result in significant loss of agricultural products during storage, processing, and handling. The need for the control of microbial infections of agricultural products is well established and a number of chemical agents have been developed for this purpose, however, to date, no fully satisfactory chemical agents have been found. Oftentimes, fungal control agents are highly toxic to crops and/or animals; consequently, restrictions are placed on their handling and use. Also, many presently available fungal control agents are of restricted utility; that is to say, a particular agent may be effective only against several types of fungus. As a result, a number of separate materials must often be employed in a particular agricultural setting in order to accommodate different types of fungi or other microbial pathogens. Also, as is common with anti-microbial agents, a number of fungal species have developed resistance to commonly employed fungicides.
Clearly, there is a need for an anti-microbial control agent which can be utilized for both bacterial and fungal agents in plants which has broad activity against a variety of fungi and bacteria including those strains resistant to presently employed fungicides. Ideally, the material should be of low toxicity to crops and to animals, stable in composition, easy to employ, and preferably low in cost.
It is well known that the cell walls of fungi are comprised of chitin, which is a natural, carbohydrate-based biopolymer. Chitin is an analog of cellulose in which the OH group at the C-2 position has been replaced by an acetamido group. Chitin is also abundantly found in a number of natural sources, including the shells of arthropods such as shrimp. Previous research has suggested that chitin, or lower molecular weight fractions produced by its degradation, can in some instances, elicit antifungal responses in some plants, see for example, M. G. Hahn et al. in
Mechanisms of Plant Defense Responses
; B. Fritig and M. Legrand, Kluwer Academic Publishers (Netherlands 1993, pp. 99-116).
Chitosan is a semi-synthetic derivative of chitin produced by the deacetylation of the nitrogen thereof so as to produce the ammonium salt. Chitosan itself has been shown to have some mild antifungal activity with regard to certain particular fungal species in some particular plants, see for example, L. A. Hadwiger, J. M. Beckman;
Plant Physiol
., 66, 205-211 (1980); A. El Gharouth et al.,
Phytopathology
, 84, 313-320 (1994); A. El Gharouth et al.,
Phytopathology
, 82, 398-402 (1992); C. R. Allan et al.,
Experimental Mycology
, 3:285-287 (1979); and P. Stossel et al.,
Phytopathology Z
., 111:82-90 (1984). Specific hydrozylates of chitosan have also been described as having some antifungal activity. See for example, Kendra et al.,
Experimental Mycology
, 8:276-281 (1984). U.S. Pat. No. 5,374,627 discloses the use of a composition of high molecular weight chitosan hydrozylate (M.W. 10,000-50,000) and acetic acid for controlling fungus in certain crops. Japanese Patent Application 62-198604 describes the use of very low molecular weight chitosan hydrozylates (M. W. ≦3,000) for the control of
Alternaria alternata
fungus in pears. It is further noted that this material is not effective, in pears, against other fungi such as Botrytis.
The ability of chitosan to form complexes with metal ions, particularly of the transition metals and post transition metal ions, is well known in the literature, see generally George A.F. Roberts,
Chitin Chemistry
, Macmillan (1992). Most of the work described in this publication was done with the insoluble form of the chitosan metal complexes dealing with different ion interactions and the type of complex formation. Almost none of the work dealt with the soluble complex formation and no suggestion was made for the use of chitosan metal complexes for use in agriculture.
U.S. Pat. No. 5,010,181 to Coughlin also discloses the use of chitosan for removing heavy metal ions from aqueous solution.
U.S. Pat. Nos. 5,643,971 and 5,541,233 both to Roenigk disclose the use of chitosan as a chelating polymer capable of forming coordinate bonds with transition metals. These metal complexes were utilized in a water-absorbing porous article, such as a sponge, in order to impart anti-microbial activity. Neither of the patents to Roenigk disclose the use of chitosan metal chelates for agricultural uses including the delivery of metal ions to plants and the use of chitosan metal chelates as anti-microbial agents against plant diseases. Accordingly, the present invention, as will be described in detail below, is directed to anti-microbial agents and/or metal delivery agents derived from chitin and/or chitosan and their methods of use in agriculture. This invention has identified particular chitosan metal chelate combinations which are particularly effective anti-microbial agents at very low doses. The material of the present invention is derived from natural sources and has extremely low toxicity to animals and agricultural crops. In addition, the material is stable, easy to handle, and low in cost. These and other advantages of the present invention will be readily apparent from the discussion, description, and examples which follow.
SUMMARY OF THE INVENTION
There is disclosed herein a method for delivering metal to plants. The method comprises combining a metal ion with chitosan to form a metal chelate complex and applying the metal chelate complex to a plant in order to deliver the metal to the plant.
There is also disclosed a chitosan metal complex comprising a chitosan chelating polymer and at least one different metal ions chelated to the chitosan chelating polymer. In a preferred embodiment, copper, zinc, and aluminum are all chelated to the chitosan chelating polymer.
Also disclosed are compositions containing chitosan metal complexes which include both a water soluble chitosan metal ion chelate and a water insoluble chitosan metal ion chelate.
Also included within the scope of the present invention are methods for treating microbial disease in plants which comprise applying the compositions of the present invention to plants either pre-harvest or post-harvest.
Also disclosed herein are soluble chitosan metal compositions suitable for hydration and application to plants.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, it has been found that particular oligomeric and/or polymeric materials derived from chitin or chitosan, having a molecular weight in the range of 4,000 to 500,000 daltons and comprised of linked, beta-glucosamine repeat units, is a highly effective chelating agent for transition metals thereby forming a highly effective agent for the control of a broad range of microbial diseases including bacterial and fungal diseases in a variety of plants.
Two different molecular weight chitosan polymer fractions can be utilized in the present invention. A first chitosan polymer fraction having a molecular weight ranging from approximately 10,000 daltons to approximately 500,000 daltons is combined with a second chitosan polymer fraction having a molecular weight ranging from approximately 4,000 daltons to approximately 10,000 daltons. It was found that for use as an anti-bacterial agent, t
Ben-Shalom Noach
Pinto Riki
Gifford, Krass, Groh Sprinkle, Anderson & Citkowski, P.C.
Owens, Jr. Howard V.
State of Israel - Ministry of Agriculture
Wilson James O.
LandOfFree
Chitosan metal complexes and method for controlling... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Chitosan metal complexes and method for controlling..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chitosan metal complexes and method for controlling... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3083475