scholarly journals Differential Inhibition of Helicoverpa armigera (Hubner) Gut Proteinases by Proteinase Inhibitors of Okra and It's Wild Relatives

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Shilpa K. Udamale ◽  
M. P. Moharil ◽  
T. B. Ugale ◽  
J. M. Mankar
Keyword(s):  
Insect Resistance ◽  
Proteinase Inhibitors ◽  
Management Strategies ◽  
Resistance Management ◽  
Trypsin Inhibitors ◽  
Wild Relatives ◽  
Proteinase Activity ◽  
Differential Inhibition ◽  
Chymotrypsin Inhibitors

The seeds of ten genotypes and twenty-nine wild relatives of okra were analysed for the presence of trypsin, chymotrypsin, and Helicoverpa gut proteinases (HGPs) inhibitors (HGPIs), with the aim to identify potent inhibitors of H. armigera gut proteinases. Proteinase inhibitors (PIs) obtained from wild relatives of okra exhibited stronger inhibition of HGPs than the genotypes of okra. In in vitro inhibitory assay against HGPs, A. tuberculatus 90396 and 90515 showed high tryptic inhibitory (71.8% and 69.2%), chymotryptic inhibitory (68.5% and 66.2%), and Helicoverpa gut proteinase activity (70.2% and 68.2%). In electrophoretic profile showed the same variation in the number of trypsin inhibitors (TIs), chymotrypsin Inhibitors (CIs), and HGPIs isoforms with different intensities, whereas genotypes of okra mostly showed monomorphic profile. Maximum eight HGPIs isoforms were found in A. tuberculatus (90396 and 90515). In bioassay studies, significant reduction in weight of H. armigera larvae was found, when larvae fed on PIs obtained from A. tuberculatus (90396 and 90515). Thus, the result of the present investigation indicates that further exploration of PIs obtained from A. tuberculatus (90396 and 90515) will be helpful for developing PIs-based insect resistance management strategies.

Proteinases in the excretory/secretory products (ES) of adult Trichinella spiralis

Parasitology ◽  
1995 ◽  
Vol 111 (2) ◽  
pp. 201-208 ◽  
Author(s):  
V. K. Todorova ◽  
D. P. Knox ◽  
M. W. Kennedy
Keyword(s):  
Size Range ◽  
Proteinase Inhibitors ◽  
Trichinella Spiralis ◽  
Proteinase Activity ◽  
Serine Proteinases ◽  
Protein Substrates ◽  
Defined Media ◽  
Metalloproteinase Inhibitors ◽  
Secretory Products

SUMMARYAdult Trichinella spiralis were maintained in vitro using defined media and the material excreted/secreted (ES) during this time examined for proteolytic enzyme (proteinase) activity using an azocasein assay and gelatin-substrate gels. Several discrete proteinases in the size range 14–100 kDa were observed with optimal activity at pH 7·5. The use of a class-differentiating panel of proteinase inhibitors indicated that serine proteinases were predominant although some inhibition was evident in the presence of cysteine and metalloproteinase inhibitors. Of a panel of potential natural protein substrates tested, ES proteinases only degraded fibrinogen and plasminogen and degradation was, in part, susceptible to the action of serine, cysteine and aspartyl proteinase inhibitors. In addition, antibody harvested from immune but not normal mice inhibited ES proteinase activity, an observation of relevance to the immunobiology of Trichinosis.

scholarly journals Evaluation of Kasugamycin for Fire Blight Management, Effect on Nontarget Bacteria, and Assessment of Kasugamycin Resistance Potential in Erwinia amylovora

2011 ◽  
Vol 101 (2) ◽  
pp. 192-204 ◽  
Author(s):  
Gayle C. McGhee ◽  
George W. Sundin
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Management Strategies ◽  
Resistance Management ◽  
Aminoglycoside Antibiotic ◽  
Relative Fitness ◽  
Industry Standard ◽  
High Concentrations ◽  
New Compounds

The emergence and spread of streptomycin-resistant strains of Erwinia amylovora in Michigan has necessitated the evaluation of new compounds effective for fire blight control. The aminoglycoside antibiotic kasugamycin (Ks) targets the bacterial ribosome and is particularly active against E. amylovora. The efficacy of Ks formulated as Kasumin 2L for control of fire blight was evaluated in six experiments conducted over four field seasons in our experimental orchards in East Lansing, MI. Blossom blight control was statistically equivalent to the industry standard streptomycin in all experiments. E. amylovora populations remained constant on apple flower stigmas pretreated with Kasumin and were ≈100-fold lower than on stigmas treated with water. Kasumin applied to apple trees in the field also resulted in a 100-fold reduced total culturable bacterial population compared with trees treated with water. We performed a prospective analysis of the potential for kasugamycin resistance (KsR) development in E. amylovora which focused on spontaneous resistance development and acquisition of a transferrable KsR gene. In replicated lab experiments, the development of spontaneous resistance in E. amylovora to Ks at 250 or 500 ppm was not observed when cells were directly plated on medium containing high concentrations of the antibiotic. However, exposure to increasing concentrations of Ks in media (initial concentration 25 μg ml–1) resulted in the selection of Ks resistance (at 150 μg ml–1) in the E. amylovora strains Ea110, Ea273, and Ea1189. Analysis of mutants indicated that they harbored mutations in the kasugamycin target ksgA gene and that all mutants were impacted in relative fitness observable through a reduced growth rate in vitro and decreased virulence in immature pear fruit. The possible occurrence of a reservoir of KsR genes in orchard environments was also examined. Culturable gram-negative bacteria were surveyed from six experimental apple orchards that had received at least one Kasumin application. In total, 401 KsR isolates (42 different species) were recovered from apple flowers and leaves and orchard soil samples. Although we have not established the presence of a transferrable KsR gene in orchard bacteria, the frequency, number of species, and presence of KsR enterobacterial species in orchard samples suggests the possible role of nontarget bacteria in the future transfer of a KsR gene to E. amylovora. Our data confirm the importance of kasugamycin as an alternate antibiotic for fire blight management and lay the groundwork for the development and incorporation of resistance management strategies.

Differential inhibition of Helicoverpa armigera gut proteinases by proteinase inhibitors of pigeonpea (Cajanus cajan) and its wild relatives

2003 ◽  
Vol 64 (3) ◽  
pp. 681-687 ◽  
Author(s):  
Nanasaheb P. Chougule ◽  
Vandana K. Hivrale ◽  
Pavanjeet J. Chhabda ◽  
Ashok P. Giri ◽  
Manvendra S. Kachole
Keyword(s):  
Helicoverpa Armigera ◽  
Cajanus Cajan ◽  
Proteinase Inhibitors ◽  
Wild Relatives ◽  
Differential Inhibition ◽  
Helicoverpa Armígera

scholarly journals Effects of the Human Immunodeficiency Virus (HIV) Proteinase Inhibitors Saquinavir and Indinavir on In Vitro Activities of Secreted Aspartyl Proteinases of Candida albicans Isolates from HIV-Infected Patients

1999 ◽  
Vol 43 (8) ◽  
pp. 2038-2042 ◽  
Author(s):  
Hans C. Korting ◽  
Martin Schaller ◽  
Gabriele Eder ◽  
Gerald Hamm ◽  
Ursula Böhmer ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Candida Albicans ◽  
Proteinase Inhibitors ◽  
Oral Candidiasis ◽  
Proteinase Activity ◽  
Dependent Manner ◽  
Immunodeficiency Virus ◽  
Dose Dependent ◽  
Pepstatin A

ABSTRACT The effects of therapeutically relevant concentrations of the human immunodeficiency virus (HIV) proteinase inhibitors saquinavir and indinavir on the in vitro proteinase activity of Candida albicans were investigated with isolates from HIV-infected and uninfected patients with oral candidiasis. After exposure to the HIV proteinase inhibitors, proteinase activity was significantly reduced in a dose-dependent manner. These inhibitory effects, which were similar to that of pepstatin A, and the reduced virulence phenotype in experimental candidiasis after application of saquinavir indicate the usefulness of these HIV proteinase inhibitors as potential anticandidal agents.

The mutual influence of proteins from Varroa destructor extracts and from honeybee haemolymph on their proteolytic activity — in vitro study

2013 ◽  
Vol 58 (3) ◽  
Author(s):  
Regina Frączek ◽  
Krystyna Żółtowska ◽  
Zbigniew Lipiński ◽  
Małgorzata Dmitryjuk
Keyword(s):  
High Activity ◽  
Proteolytic Activity ◽  
Varroa Destructor ◽  
Ethylenediaminetetraacetic Acid ◽  
Mutual Influence ◽  
Proteinase Inhibitors ◽  
Proteinase Activity ◽  
Moderate Activity ◽  
Kunitz Inhibitor

AbstractThe influence of extracts from Varroa destructor, a parasitic mite of the honeybee Apis mellifera, on the proteinase activity of worker bee haemolymph was analysed in vitro, along with the influence of bee haemolymph on the proteolytic activity of V. destructor extract. The study was conducted in three different environments: pH 7.5 (high activity of bee enzymes and very low activity of parasite enzymes), pH 5 (moderate activity of enzymes from both sources) and pH 3.5 (limited activity of bee proteinases and high activity of mite proteinases). Based on electrophoretic studies, the inhibition of the activity of bee haemolymph proteinases by V. destructor extracts was observed at each pH. The study at pH 7.5 with commercial inhibitors of the 4 main classes of proteinases (pepstatin A, ethylenediaminetetraacetic acid (EDTA), E-64 (trans-epoxysuccinyl-L-leucylamido-(4-guanidino)-butane), soybean trypsin inhibitor and Kunitz inhibitor) suggested that parasite extracts mainly inhibited serine proteinases and, to a lower degree, cysteine and aspartyl proteinases. At pH 3.5 and pH 5, a decrease of approximately 40% in parasite proteinase activity was also observed in the presence of bee haemolymph. The result points to the presence of aspartyl proteinase inhibitors in bee haemolymph, which may be an important defence element for bees during food intake by a mite. It was demonstrated that trypsin and trypsin inhibitors are active in the excretion/secretion products of V. destructor, the proteinases of which may assist the parasite in food suckling by preventing haemolymph coagulation, among other things.

Cotton Fleahopper1 Biology and Ecology Relevant to Development of Insect Resistance Management Strategies

2021 ◽  
Vol 46 (1) ◽  
Author(s):  
Kristin Hamons ◽  
Tyler Raszick ◽  
Lindsey Perkin ◽  
Gregory Sword ◽  
Charles Suh
Keyword(s):  
Insect Resistance ◽  
Management Strategies ◽  
Resistance Management ◽  
Insect Resistance Management

scholarly journals Genetic Markers for Western Corn Rootworm Resistance to Bt Toxin

2015 ◽  
Vol 5 (3) ◽  
pp. 399-405 ◽  
Author(s):  
Lex E Flagel ◽  
Shilpa Swarup ◽  
Mao Chen ◽  
Christopher Bauer ◽  
Humphrey Wanjugi ◽  
...  
Keyword(s):  
Genetic Markers ◽  
Insect Resistance ◽  
Management Strategies ◽  
Resistance Management ◽  
The United States ◽  
Western Corn Rootworm ◽  
Economic Losses ◽  
Corn Rootworm ◽  
Insect Resistance Management ◽  
Bt Toxin

Abstract Western corn rootworm (WCR) is a major maize (Zea mays L.) pest leading to annual economic losses of more than 1 billion dollars in the United States. Transgenic maize expressing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely used for the management of WCR. However, cultivation of Bt-expressing maize places intense selection pressure on pest populations to evolve resistance. Instances of resistance to Bt toxins have been reported in WCR. Developing genetic markers for resistance will help in characterizing the extent of existing issues, predicting where future field failures may occur, improving insect resistance management strategies, and in designing and sustainably implementing forthcoming WCR control products. Here, we discover and validate genetic markers in WCR that are associated with resistance to the Cry3Bb1 Bt toxin. A field-derived WCR population known to be resistant to the Cry3Bb1 Bt toxin was used to generate a genetic map and to identify a genomic region associated with Cry3Bb1 resistance. Our results indicate that resistance is inherited in a nearly recessive manner and associated with a single autosomal linkage group. Markers tightly linked with resistance were validated using WCR populations collected from Cry3Bb1 maize fields showing significant WCR damage from across the US Corn Belt. Two markers were found to be correlated with both diet (R2 = 0.14) and plant (R2 = 0.23) bioassays for resistance. These results will assist in assessing resistance risk for different WCR populations, and can be used to improve insect resistance management strategies.

scholarly journals Resistance mutation conserved between insects and mites unravels the benzoylurea insecticide mode of action on chitin biosynthesis

2016 ◽  
Vol 113 (51) ◽  
pp. 14692-14697 ◽  
Author(s):  
Vassilis Douris ◽  
Denise Steinbach ◽  
Rafaela Panteleri ◽  
Ioannis Livadaras ◽  
John Anthony Pickett ◽  
...  
Keyword(s):  
Genome Editing ◽  
Mode Of Action ◽  
Management Strategies ◽  
Resistance Management ◽  
Resistance Mutation ◽  
Bioactive Molecules ◽  
Agricultural Pests ◽  
Homology Directed Repair ◽  
A Genome

Despite the major role of chitin biosynthesis inhibitors such as benzoylureas (BPUs) in the control of pests in agricultural and public health for almost four decades, their molecular mode of action (MoA) has in most cases remained elusive. BPUs interfere with chitin biosynthesis and were thought to interact with sulfonylurea receptors that mediate chitin vesicle transport. Here, we uncover a mutation (I1042M) in the chitin synthase 1 (CHS1) gene of BPU-resistantPlutella xylostellaat the same position as the I1017F mutation reported in spider mites that confers etoxazole resistance. Using a genome-editing CRISPR/Cas9 approach coupled with homology-directed repair (HDR) inDrosophila melanogaster, we introduced both substitutions (I1056M/F) in the corresponding flyCHS1gene (kkv). Homozygous lines bearing either of these mutations were highly resistant to etoxazole and all tested BPUs, as well as buprofezin—an important hemipteran chitin biosynthesis inhibitor. This provides compelling evidence that BPUs, etoxazole, and buprofezin share in fact the same molecular MoA and directly interact with CHS. This finding has immediate effects on resistance management strategies of major agricultural pests but also on mosquito vectors of serious human diseases such as Dengue and Zika, as diflubenzuron, the standard BPU, is one of the few effective larvicides in use. The study elaborates on how genome editing can directly, rapidly, and convincingly elucidate the MoA of bioactive molecules, especially when target sites are complex and hard to reconstitute in vitro.

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