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  • 1
    Electronic Resource
    Electronic Resource
    Dynamics of fluoroescent probe-cholinesterase reactions (1972)
    s.l. : American Chemical Society
    Biochemistry 11 (1972), S. 2082-2090 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00761a014
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of chitinases and β-1,3-glucanases in grapefruit flavedo during fruit development (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 99 (1997), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Chitinase (EC 3.2.1.14) and β-1,3-glucanase (EC 3.2.1.39) activities in the flavedo of grapefruit (Citrus paradisi cv. Marsh) were determined at 17 times during the course of fruit development. Chitinase activity is initially high in flavedo, but drops rapidly and is low, although fairly constant throughout the remainder of fruit development. In contrast to chitinase, β-1,3-glucanase activity is lowest in young fruit and increases during development. Western blots of crude flavedo extracts following SDS-PAGE were probed with antibodies raised against purified citrus chitinase and β-1,3-glucanase. Results of immunostaining revealed that changes in the activities of chitinase and β-1,3-glucanase were reflected in the amount of chitinase and glucanase protein present in the extracts. Only a single chitinase band was detected on western blots of crude flavedo extracts, whereas one glucanase band was present in young fruit and a second one appeared later in older fruit. Partial purification of flavedo chitinases and glucanases was performed using extracts prepared from immature and mature fruit for the two enzymes, respectively. Acidic and basic forms of both enzymes were present in the extracts; acidic and basic forms of chitinase were present in nearly equal amounts whereas basic glucanases predominated (91% of total activity). Acidic and basic chitinases differed in substrate specificity as well as products of degradation indicating the heterogeneous nature of the enzymes. Both acidic and basic glucanases required the presence of β-1,3 linkages for activity, were active against both soluble and insoluble β-1,3 glucans and generated similar products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1997.tb00564.x
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  • 3
    Electronic Resource
    Electronic Resource
    5-Dimethylaminonaphthalene-1-sulfonic acid (DANS acid) as standard for quantum yield of fluorescence (1970)
    s.l. : American Chemical Society
    Analytical chemistry 42 (1970), S. 130-132 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60283a038
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  • 4
    Electronic Resource
    Electronic Resource
    Juvenile hormone analogs as in vitro inhibitors of rat liver microsomal oxidases (1973)
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 21 (1973), S. 360-362 
    Details
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jf60187a044
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  • 5
    Electronic Resource
    Electronic Resource
    Citrus rootstock responses to herbivory by larvae of the sugarcane rootstock borer weevil (Diaprepes abbreviatus) (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 94 (1995), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The responses of roots to feeding by larvae of a citrus root weevil (Diaprepes abbreviatus) were investigated in Citrus grandis (L.) Osb. x Poncirus trifoliata (2N) (L.) Raf.; C. grandis x P. trifoliata (4N); P. trifoliata x C. grandis (Flying Dragon x Nakon); C. paradisi Macf. x P. trifoliata (Swingle citrumelo); C. aurantifolia (Christm.) Swingle (Citrus macrophylla); C. reticulata Blanco (Cleopatra mandarin); C. sinensis (L.) Osb. x P. trifoliata (Carrizo citrange); C. aurantium (L.) (sour orange). Chitinase, chitosanase. β-1,3-glucanase, peroxidase and lysozyme activities were measured and significant differences were observed for some of the cultivars between infested and uninfested rootstocks. Generally, increased activities were observed for chitinases and decreased activities were observed for the other enzymes measured. Numerous significant differences in hydrolase and peroxidase activities were observed between cultivars. Immunological detection revealed that new protein bands occurred in root protein extracts for six of the eight cultivars infested with larvae when an antibody to a class I potato leaf chitinase was used. Antibodies generated against two citrus chitinases of Mr 24 000 (basic chitinase cv. Valencia (C. sinensis) callus, BCVC) and Mr 28 000 (basic chitinase/lysozyme cv. Valencia callus, BCLVC) indicated that chitinases in Carrizo were induced in infested roots when the BCVC antibody was employed. These findings justify calling these proteins pathogenesis-related proteins. The chitinase that BCLVC was prepared from exhibited high lysozyme activities, and the results of western blots showed the presence of proteins at Mr 24 000 and 27 000 which are presumed to be lysozymes. Similar tests using antibodies against β-1, 3-glucanases and peroxidases indicated a diminution of protein bands that cross-reacted with infested root protein extracts compared with what occurred in controls. All of the root extracts were tested against chitosans with various percentages of acetylation; activities were linearly dependent on the amount of chitosan acetylation; i.e. the larger the amount of acetylation, the greater the activity. Significant differences in hydrolase activities were observed between infested and uninfested roots for the rootstocks using the variously acetylated substrates. All of the root protein extracts were capable of degrading peritrophic membranes removed from larvae of D. abbreviatus. This suggests that citrus chitinases may play a role in disrupting the peritrophic membrane such that ingested substances that pose a hazard to the insect may penetrate the membrane more easily.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1995.tb00798.x
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  • 6
    Electronic Resource
    Electronic Resource
    Characterization of seven basic endochitinases isolated from cell cultures of Citrus sinensis (L.) (1996)
    Springer
    Planta 200 (1996), S. 289-295 
    Details
    ISSN: 1432-2048
    Keywords: Citrus ; Chitinases ; Chitosanase ; Lysozymes ; Pathogenesis-related proteins ; Plant defense
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Seven endochitinases (EC 3.2.1.14) (relative molecular masses 23000–28000 and isoelectric points 10.3–10.4) were purified from nonembryogenic Citrus sinensis L. Osbeck cv. Valencia callus tissue. The basic chitinase/lysozyme from this tissue (BCLVC) exhibited lysozyme, chitinase and chitosanase activities and was determined to be a class III chitinase. While BCLVC acted as a lysozyme at pH 4.5 and low ionic strength (0.03) it acted as a chitinase/chitosanase at high ionic strengths (0.2) with a pH optimum of ca. 5. The lysozyme activity of BCLVC was inhibited by histamine, imidazole, histidine and the N-acetyl-d-glucosamine oligosaccharide (GlcNAc)3. The basic chitinase from cv. Valencia callus, BCVC-2, had an N-terminal amino acid sequence similar to tomato and tobacco AP24 proteins. The sequences of the other five chitinases were N-terminal blocked. Whereas BCLVC was capable of hydrolyzing 13.8–100% acetylated chitosans and (GlcNAc)4–6 oligosaccharides, BCVC-2 hydrolyzed only 100% acetylated chitosan, and the remaining enzymes expressed varying degrees of hydrolytic capabilities. Experiments with (GlcNAc)2–6 suggest that BCLVC hydrolysis occurs in largely tetrasaccharide units whereas hydrolysis by the other chitinases occurs in disaccharide units. Cross-reactivities of the purified proteins with antibodies for a potato leaf chitinase (AbPLC), BCLVC, BCVC-3, and tomato AP24 indicate that these are separate and distinct proteins. Mention of a trademark, warranty, propriety, or vendor does not constitute a guarantee by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products or vendors that may also be suitable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00200295
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  • 7
    Electronic Resource
    Electronic Resource
    Elicitors of Plant Defensive Systems Reduce Insect Densities and Disease Incidence (1998)
    Springer
    Journal of chemical ecology 24 (1998), S. 135-149 
    Details
    ISSN: 1573-1561
    Keywords: Elicitor ; induced response ; leafminers ; pathogenesis-related protein ; plant defense ; tomatoes ; whitefly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Some elicitors of plant defensive systems can induce biochemical changes that enable the plant to reduce disease incidence; however, little is known about the effect of these induced responses on insect herbivores. We approached this problem using exogenous field applications of several abiotic elicitors of defensive systems in tomatoes (Lycopersicon esculentum), and evaluated the ability of the elicitors [benzo(1,2,3)thiadiazole-7-carbothioic acid (S)-methyl ester (BTH, Actigard); Probenazole; chitosan; salicylic acid; KeyPlex 350; KeyPlex DP2; and KeyPlex DP3] to reduce pest densities and to provide cross-resistance against various insect herbivores and pathogens. Only BTH provided cross-resistance and significantly reduced the incidence of bacterial spot (Xanthomonas campestris pv. vesicatoria), early blight (Alternaria solani), leaf mold (Fulvia fulva), and leafminer larval densities (Liriomyza spp.). The effects on leafminer larval densities were more pronounced during the early stages of plant development. A trend of reduced densities of whiteflies (Bemisia argentifolii) and powdery mildew (Oidium sp.), although not significant, was also found on the BTH-treated plants. Other elicitors had no significant effect on insect populations, but Probenazole and KeyPlex 350 significantly reduced bacterial spot and early blight incidence. The antiherbivore effects of BTH on leafminers was confirmed in a laboratory two-choice experiment. Adult leafminers preferred untreated plants to the BTH-treated tomatoes as ovipositioning host plants, generally corresponding with larval performance. BTH induced high levels of pathogenesis-related proteins in tomato plants including peroxidase, lysozymes, chitinase, and β-1,3-glucanases. The possible cross-resistance role of these proteins is discussed. The demonstration that exogenous induction of plant defensive systems in the field can result in lower damage caused by various pathogens and insects, supports the hypothesis that plant defensive systems may be general.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022397130895
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  • 8
    Electronic Resource
    Electronic Resource
    The Role of Plant Rapidly Induced Responses in Asymmetric Interspecific Interactions Among Insect Herbivores (1999)
    Springer
    Journal of chemical ecology 25 (1999), S. 1961-1979 
    Details
    ISSN: 1573-1561
    Keywords: Herbivory ; induced response ; interspecific interactions ; leafminers ; pathogenesis related proteins ; plant defense ; tomato ; whiteflies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The role of induced responses of tomato, Lycopersicon esculentum, in interspecific interactions between two polyphagous herbivores, the silverleaf whitefly, Bemisia argentifolii (WF), and the vegetable leafminer, Liriomyza trifolii (LM), was characterized in laboratory and field experiments. Feeding by LMs and WFs induced local and systemic production of putative defensive proteins, i.e., chitinases, peroxidases, β-1,3-glucanases, and lysozymes. The magnitude of the induction for each defensive protein varied between species. Unlike WFs, LMs caused a 33% local reduction in total foliar protein content. In a whole-plant choice experiment, adult LM feeding, oviposition, and larval survival were reduced by 47.7%, 30.7%, and 26.5%, respectively, for the WF-infested host compared with the controls. Early WF infestations also had negative systemic (plant-mediated) effects on LMs. Adult LMs preferred leaves from control plants to leaves of plants that had been previously infested with WFs; no reciprocal effect of LMs on WFs were found. Feeding by Helicoverpa zea larvae, which has been shown previously to affect LM performance, had no effect on WF survival and development. LM natural population dynamics were monitored on WF-preinfested and control plants in a field experiment. WF-infested plants were less suitable for LM development with an overall 41% reduction in LM population density. These results demonstrate asymmetric direct and plant-mediated interspecific interactions between generalist herbivores feeding simultaneously on the same host. Possible mechanisms by which WFs overcome plant defenses are suggested. This ability may also contribute to WF success that makes them a major pest worldwide. The study supports the idea that over an evolutionary time scale, herbivores sharing the same host plant will automatically compete.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020998219928
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of diflubenzuron on growth of malignant melanoma and skin carcinoma tumors in mice (1984)
    Springer
    Investigational new drugs 2 (1984), S. 19-27 
    Details
    ISSN: 1573-0646
    Keywords: diflubenzuron ; growth regulator ; solid tumors ; tumor growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The insect growth regulator diflubenzuron (DFB), which may also inhibit growth of imaginal epidermal cells in insects, was studied for antitumor activity in two mouse tumor models of epidermal origin. DFB inhibits chitin deposition, but the mechanisms by which DFB controls chitin deposition or regulates growth of insect epidermal cells are unknown. A single injection of 20 mg (800 mg/kg) of DFB into C57BL/6 mice with B16 malignant melanomas or AKR mice with skin tumors (CA 1025) induced a rapid (24 h) decrease in tumor volume in 78% and 66% of the tumors, respectively. In contrast, 85% of the melanomas and 91% of skin tumors in control mice increased in volume during the same 24-h period. Tumor volume decreased by as much as 55% for about 1% of the tumors, but the median decrease was 20% for both types of tumors. Since control tumors concommitantly increased, DFB-treated tumors decreased, relatively, to 60% of the volume of matched control tumors. After the initial volume decrease, both types of tumors resumed exponential growth resulting in an average growth curve delay, calculated for 12–14 days, of about 2.0 days. Subsequent treatment of melanomas with DFB 24 h after the initial treatment resulted in a further decrease in relative tumor volume to 40–50% of control tumor volume and a growth curve delay of 2.6 days. The most effective regimen used was 5 daily, 20-mg doses of DFB. Melanomas decreased to 40% of control tumor volume after the third injection and the mean growth curve delay was extended to 4.3 days. These data suggest that DFB, one of many benzoylphenyl ureas, has antitumor activity and further that the effects are dose-schedule dependent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00173783
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  • 10
    Electronic Resource
    Electronic Resource
    Storage proteins of the fall webworm, Hyphantria cunea drury (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 10 (1989), S. 115-130 
    Details
    ISSN: 0739-4462
    Keywords: hemolymph ; fat body ; yolk protein ; vitellogenin ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Two storage proteins, storage protein-1 (SP1) and storage protein-2 (SP2), were found in hemolymph and fat body during the development of Hyphantria cunea, the fall webworm. Both storage proteins show similiar quantitative changes during development in males and females; however, SP1 is more abundant. The hemolymph of last instar larvae contains high concentrations of the storage proteins. However, following pupation, the storage proteins accumulate in fat bodies. SP1 peaks in the hemolymph of males and females late in last instar larvae (8-day-old 7th instar larvae).SP1 has a native molecular weight of 460,000 and consists of six identical subunits (Mr = 76,700), while SP2 has a molecular weight of 450,000 and is composed of two different subunits (Mr = 74,100 and 72,400). Both SP1 and SP2 are hexamers and are phosphorylated glycolipoproteins. The pl values of SP1 and SP2 were determined to be 5.70 and 5.50, respectively.Antibodies raised against SP1 react positively with vitellogenin and ovary extract, as well as with proteins in the hemolymph from last instar larvae and proteins in pupal fat bodies. Storage protein synthesis starts in fat bodies of a 4-day-old 7th instar larvae and in female peaks at 6-8 days of the 7th instar.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940100203
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