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Nick E. Christians and Dianna L. Liu

It has previously been reported that a byproduct of the corn (Zea mays L.) wet-milling process, corn gluten meal, has potential as a natural preemergence herbicide for use in turf and certain horticultural crops. In 1993, two additional patents were issued on the technology. The first is on the use of hydrolyzed proteins from corn and other grains that were shown to have higher levels of herbicidal activity than the corn gluten meal. These materials are water soluble and can be sprayed on the soils surface. The second patent was on 5 dipeptides extracted from the hydrolyzed corn gluten meal. These dipeptides were shown to have the same type of biological activity observed when the corn gluten meal and the hydrolyzed meal are applied to the soil. The possible use of the hydrolyzed grains and the dipeptides as natural preemergence herbicides in horticultural crops will be discussed.

Open access

Guoqiang Wang, Ping Qu, Hongying Huang, Guofeng Wu, and Haijun Yan

Biological Technology Co. (Zhejiang, China). Organic manure (composted manure–straw mixture) was purchased from Nanjing Ningliang Bio-engineering Co. (Nanjing, China). Preparation of hydrolyzed soy protein-modified urea formaldehyde adhesives . Soy protein

Open access

Sofía Gómez and Celina Gómez

mixtures are generally obtained by chemical or enzymatic protein hydrolysis often using plant or animal by products ( Colla et al., 2015 ; du Jardin, 2015 ; Schaafsma, 2009 ). Hydrolyzed proteins have been shown to increase iron and N metabolism, nutrient

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T. Gregory McCollum, Hamed Doostdar, Michael Burkhart, Randall Neidz, Richard T. Mayer, and Roy E. McDonald

Inhibition of the growth of fungal pathogens has been related to levels of a β-1,3-endoglucanase (EC 3.2.1.39) (GLU) in citrus as well as other plant species. Our long-term objective is to transform Citrus spp. to express enhanced levels of GLU with the aim of increasing resistance to fungal pathogens. We have purified a β-1,3-endoglucanase from nonembryogenic Citrus sinensis (L.) Osbeck cv. Valencia callus to electrophoretic homogeneity by means of pH precipitation and ion exchange chromatography. The protein has an apparent M r of 32.5 and a pI > 10. The enzyme hydrolyzes laminarin (Laminaria digitata) optimally at pH 5 and 50°C. The enzyme will hydrolyze any glucan polymer with a β-1,3 linkage whether soluble or insoluble and the rate of hydrolysis is proportional to the relative abundance of β-1,3 linkages. The enzyme does not hydrolyze cellulose or starch. Product characterization by thin-layer chromatography indicates that the enzyme is an endohydrolase. Initial attempts to sequence the protein indicated that it was N-terminally blocked. Therefore the protein was hydrolyzed using AspN, the fragments separated by SDS-PAGE, blotted onto nitrocellulose, and one of the fragments was sequenced. Amino acid sequence analysis indicated that the protein shared homology with a number of β-1,3-endoglucanases. Antibody to the purified protein was raised in rabbits and used to screen an amplified cDNA library prepared from Citrus sinensis (L.) Osbeck cv. Valencia callus. One of the positive clones was selected and sequence analysis indicated that the clone was homologous with other β-1,3-endoglucanases.

Open access

Amanda J. Davis and Bernadine C. Strik

–0–0) (Westbridge Agricultural Products, Vista, CA) were used in 2017 and 2018–20, respectively; both are a hydrolyzed soy-protein–based fertilizer source. These products were chosen based on their low levels of nutrients other than N, as high levels of K found in

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Bruce A. Kimball, Dale L. Nolte, and Kelly B. Perry

Hydrolyzed casein (HC) and retail products that contain HC are evaluated as repellents to minimize deer damage to trees and shrubs. Three different experiments demonstrate that HC is an effective deer repellent. Technical-grade HC completely eliminated browse damage to evergreen shrubs (Gaultheria shallon Pursh.) and conifers (Thuja plicata Donn.) during the test periods. Retail sources of HC (concentrated baby formula powders) are not as effective as pure hydrolyzed protein, but do offer browse protection when alternative sources of browse are available. For nursery, orchard, and reforestation applications, HC is a promising deer repellent to minimize losses due to browse. For the private homeowner, a simple repellent formulated with glue and a HC-containing baby formula may offer considerable browse protection when alternative forage is available.

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Jong-Pil Chun and Donald J. Huber

The high catalytic potential of PG evident in reactions with soluble pectic polymers is typically not expressed in vivo. In this study, the binding and catalytic properties of PG isozyme 2, and the influence of the B-subunit protein, were investigated using cell walls prepared from tomato fruit expressing the B-subunit antisense gene. Cell walls were prepared from mature-green fruit and treated to remove/inactivate endogenous enzymes. Walls were then preloaded with rate-limiting quantities of purified PG 2, and incubated under catalysis-promoting conditions over the range of pH from 4.5 to 6.0. Cell walls of both B-subunit antisense and wild-type fruit retained comparable quantities of loaded PG 2. The enzymic release of pectin from PG-loaded walls was proportional to the quantity of wall-bound PG 2. In walls lacking the B-subunit protein, the quantity of pectin released by a given dose of wall-associated PG was as much as 2-fold higher than from wild-type walls. The B-subunit protein also influenced the extent of pectin depolymerization during ripening. The release of pectin from cell walls during periods of catalysis was not the sole indicator of the range of pectins hydrolyzed. Treating postcatalytic loaded cell walls to inactivate PG, and subsequent extraction of residual wall pectins using 50 mm CDTA solutions solubilized polymers of significantly lower mol mass compared with pectins solubilized directly from nonloaded cell walls.

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Jong-Myung Choi and Paul V. Nelson

The structure of feather keratin protein was modified in attempts to develop a slow-release N fertilizer of 12 weeks duration or longer by steam hydrolysis to break disulfide bonds, enzymatic hydrolysis with Bacillus licheniformis (Weigmann) to break polypeptide bonds, and steam hydrolysis (autoclaving) to hasten mineralization followed by cross-linking of the protein by a formaldehyde reaction to control the increased rate of mineralization. Release of N in potting substrate within elution columns from ground, but otherwise untreated, raw feathers occurred mainly during the first 5 weeks with a much smaller release occurring from weeks 8 to 12. Steam hydrolysis resulted in an increase of N during the first 5 weeks and a decrease during weeks 8 to 11. Cumulative N release over 11 weeks increased from 12% in raw feathers to 52% for feathers steam hydrolyzed for 90 minutes. This favored an immediately available fertilizer but not a slow-release fertilizer. Microbial hydrolysis with B. licheniformis resulted in a modest reduction of N release during the first 5 weeks and a small increase during weeks 8 to 11. Both shifts, while not desirable for an immediately available fertilizer, enhanced the slow-release fertilizer potential of feathers but not sufficiently to result in a useful product. Steam hydrolyzed feathers cross-linked with quantities of formaldehyde equal to 5% and 10% of the feather weight released less N during the first 5 weeks, more during weeks 6 and 7, and less during weeks 9 to 12 compared to raw feathers. The first two shifts were favorable for a slow-release fertilizer while the third was not.

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Dominique Michaud, Thierry C. Vrain, and Hugh A. Daubeny

Transformation of plant genomes with cysteine proteinase inhibitor (cystatin) genes represents an attractive option for the biological control of insect pests. However, this strategy must be carefully considered, because the transgenic plant endogenous proteinases may represent potential target enzymes for the exogenous inhibitors produced. For example, we are considering the transformation of strawberry (Fragaria ×ananassa) with cystatin cDNA clones, to control the Coleoptera pest black vine weevil (BVW; Otiorynchus sulcatus). Electrophoretic analyses of adult BVW proteinases have revealed the involvement of at least five proteinase forms for protein digestion, and the major form was strongly inhibited by oryzacystatins (OCI and OCII), two cystatins isolated from rice seeds. A similar analysis of proteinases showed the existence of OC-sensitive proteinase activity in the leaves of strawberry, suggesting a possible risk of interference of the inhibitors in the transformed plants. In addition, the two rice inhibitors were rapidly hydrolyzed at 25C when incubated with proteinase extracts from either young, mature or senescent leaves. An efficient control of BVW by plant cystatin-expressing transgenic strawberry plants is therefore potentially possible, but the correct targeting of the inhibitors in the plant cells using appropriate signal peptides could be necessary.

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Kimberly A. Williams and Paul V. Nelson

Seven organic materials including 1) the bacterium Brevibacterium lactofermentum (Okumura et al.) in a nonviable state, 2) a mixture of two bacteria, Bacillus licheniformis (Weigmann) and Bacillus subtilis (Ehrenberg), plus the fungus Aspergillus niger (van Tieghem) in a nonviable state, 3) an activated microbial sludge from waste-water treatment, 4) sludge from a poultry manure methane generator, 5) unsteamed bonemeal, 6) aged pine needles, and 7) poultry feathers were evaluated to determine their pattern and term of N release and the possibility of using them as an integral part of root media releasing N at a steady, low rate over 10 to 12 weeks for production of Dendranthema × grandiflorum (Ramat.) Kitamura `Sunny Mandalay'. These were compared to the inorganic slow-release fertilizer micro Osmocote (17N-3.9P-10.8K) and a weekly liquid fertilizer control. All organic sources released N most rapidly during the first 2 weeks, followed by a decline, which ended at 6 to 7 weeks. Brevibacterium lactofermentum, bonemeal, and micro Osmocote treatments resulted in about equal growth, which was similar to growth of a weekly liquid fertilizer control for 9 weeks in the first and for 12 weeks in the second experiment. The period of N release could not be extended through increased application rate of source due to the high initial release rate. It was not possible to lower source application rates to achieve an effective, low soil solution concentration due to the large variation in release rate over time. Efficiency of N use varied among plants grown in media treated with various microorganismal sources and was highest in those treated with B. lactofermentum. Nitrogen release from ground poultry feathers was inadequate, and additions of the viable hydrolyzing bacterium B. licheniformis to feathers failed to increase soil solution N levels. Attempts to retard mineralization of B. lactofermentum by cross-linking proteins contained within the bacterium by means of heat treatment at 116C vs. 82C failed. While anaerobic poultry manure sludge proved to be an inefficient source of N, it provided large amounts of P. Organic sources released primarily ammoniacal N, which raised the medium pH by as much as one unit, necessitating the use of less limestone in the medium formulation.