scholarly journals Comparison and Validation of Methods To Quantify Cry1Ab Toxin from Bacillus thuringiensis for Standardization of Insect Bioassays

2007 ◽  
Vol 74 (1) ◽  
pp. 130-135 ◽  
Author(s):  
André L. B. Crespo ◽  
Terence A. Spencer ◽  
Emily Nekl ◽  
Marianne Pusztai-Carey ◽  
William J. Moar ◽  
...  

ABSTRACT Standardization of toxin preparations derived from Bacillus thuringiensis (Berliner) used in laboratory bioassays is critical for accurately assessing possible changes in the susceptibility of field populations of target pests. Different methods were evaluated to quantify Cry1Ab, the toxin expressed by 80% of the commercially available transgenic maize that targets the European corn borer, Ostrinia nubilalis (Hübner). We compared three methods of quantification on three different toxin preparations from independent sources: enzyme-linked immunosorbent assay (ELISA), sodium dodecyl sulfate-polyacrylamide gel electrophoresis and densitometry (SDS-PAGE/densitometry), and the Bradford assay for total protein. The results were compared to those obtained by immunoblot analysis and with the results of toxin bioassays against susceptible laboratory colonies of O. nubilalis. The Bradford method resulted in statistically higher estimates than either ELISA or SDS-PAGE/densitometry but also provided the lowest coefficients of variation (CVs) for estimates of the Cry1Ab concentration (from 2.4 to 5.4%). The CV of estimates obtained by ELISA ranged from 12.8 to 26.5%, whereas the CV of estimates obtained by SDS-PAGE/densitometry ranged from 0.2 to 15.4%. We standardized toxin concentration by using SDS-PAGE/densitometry, which is the only method specific for the 65-kDa Cry1Ab protein and is not confounded by impurities detected by ELISA and Bradford assay for total protein. Bioassays with standardized Cry1Ab preparations based on SDS-PAGE/densitometry showed no significant differences in LC50 values, although there were significant differences in growth inhibition for two of the three Cry1Ab preparations. However, the variation in larval weight caused by toxin source was only 4% of the total variation, and we conclude that standardization of Cry1Ab production and quantification by SDS-PAGE/densitometry may improve data consistency in monitoring efforts to identify changes in insect susceptibility to Cry1Ab.

2006 ◽  
Vol 13 (10) ◽  
pp. 1155-1161 ◽  
Author(s):  
Donghee Cho ◽  
Michael T. Collins

ABSTRACT The protein expression profiles and antigenicities of both culture filtrates (CF) and cellular extracts (CE) of Mycobacterium paratuberculosis were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), one-dimensional electrophoresis (1-DE) and 2-DE immunoblotting, and enzyme-linked immunosorbent assay (ELISA). The CF proteins were harvested from supernatants of stationary-phase liquid cultures and concentrated by size exclusion filtration. The CE proteins were extracted by mechanical disruption of cells using glass beads and a high-speed agitator. Analysis of SDS-PAGE gels showed that the majority of CF proteins had low molecular masses (<50 kDa), whereas CE protein mass ranged more evenly over a broader range up to 100 kDa. By 2-DE, CF proteins had a narrow array of pI values, with most being between pH 4.0 and 5.5; CE proteins spanned pI values from pH 4.0 to 7.0. The antigenicities of CF and CE proteins were first determined by 1-DE and 2-DE immunoblotting with serum from a cow naturally infected with M. paratuberculosis. The serum reacted strongly to more proteins in the CF than the CE. Sera from 444 infected and 412 uninfected cattle were tested by ELISA with CF and CE as solid-phase antigens. Receiver-operator characteristic curve analysis of the ELISA results showed a significantly greater area under the curve for CF compared to CE (P < 0.05). A high degree of variability in protein binding patterns was shown with 1-DE immunoblot analysis with 31 sera from M. paratuberculosis-infected cattle. Collectively, these results indicate that serologic tests for bovine paratuberculosis may be improved by using proteins derived from CF instead of CE. To maximize the diagnostic sensitivity of serologic tests, multiple proteins will be required. Even so, a CF ELISA may not be able to detect all M. paratuberculosis-infected cattle, in particular those in the early stages of infection that have yet to mount an antibody response.


Blood ◽  
1992 ◽  
Vol 79 (1) ◽  
pp. 161-168 ◽  
Author(s):  
Y Tomiyama ◽  
R Kekomaki ◽  
J McFarland ◽  
TJ Kunicki

Abstract We have characterized a 120-Kd antigen that frequently reacts with serum antibodies from patients with immune thrombocytopenia or normal subjects. Immunoblots made after two-dimensional nonreduced/reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) or two-dimensional isoelectric focusing/SDS-PAGE demonstrated that this 120-Kd protein has the same molecular weight under nonreduced or reduced conditions, is not a surface protein, and has an isoelectric point (pl) of 6.4 to 6.5. From these data, one likely candidate is the intracellular platelet protein, vinculin. Monoclonal antivinculin antibody reacts with this 120-Kd protein, and purified human platelet vinculin is bound by antibodies that recognize the 120-Kd protein. Therefore, we conclude that this 120-Kd protein is identical to vinculin. Data obtained from a sensitive enzyme-linked immunosorbent assay demonstrate the presence of naturally occurring antivinculin antibodies in many normal sera. However, the incidence of antivinculin antibodies in patient sera (67%; 55 of 82 sera) is significantly (P less than .01) higher than that in normal sera (40%; 32 of 80 sera), and there is a significant difference (P less than .05) between the mean levels of antivinculin antibodies in patient and normal sera. Whereas the levels of these antibodies in patient and normal sera overlap, 2 of 82 sera from patients with thrombocytopenia express unusually high levels of such antibodies. The pathologic significance of these antibodies remains to be determined.


1998 ◽  
Vol 66 (1) ◽  
pp. 289-296 ◽  
Author(s):  
Morten Harboe ◽  
Harald G. Wiker ◽  
Gunni Ulvund ◽  
Bent Lund-Pedersen ◽  
Åse Bengård Andersen ◽  
...  

ABSTRACT Culture fluids after growth of Mycobacterium bovis BCG on Sauton medium contain actively secreted proteins and proteins released by bacterial lysis. BCG culture fluids and sonicates ofMycobacterium tuberculosis and Mycobacterium paratuberculosis were tested after separation by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The localization of marker proteins was determined by enzyme-linked immunosorbent assay and Western blotting with selected monoclonal antibodies of known specificities. Soluble secreted proteins (MPB64 and proteins of the antigen 85 complex) and three heat shock proteins (DnaK, GroEL, and GroES) were recovered in a single peak after gel filtration, indicating their occurrence as a free monomer in the culture fluid and cytosol, respectively. Other constituents eluted in two distinct peaks during gel filtration. The first peak corresponded to the void volume, indicating complex formation between several proteins or attachment to lipids in the surface layer or the cytoplasmic membrane; the second peak corresponded to the expected monomer size indicated by SDS-PAGE under conditions that separate proteins from each other during sample preparation. The two-peak group contained constituents with known lipid contents, the 19- and 38-kDa lipoproteins and lipoarabinomannan. The 26-kDa form of MPB83 behaved similarly. After extraction with Triton X-114, these constituents entered into the detergent phase, confirming the lipoprotein nature of 26-kDa MPB83. The MPB83 molecule was shown to be available on the surface of BCG Tokyo bacilli for reaction with monoclonal antibody MBS43 by flow cytometry.


2014 ◽  
Vol 9 (3) ◽  
pp. 449
Author(s):  
Desy Sugiani ◽  
Angela Mariana Lusiastuti ◽  
Sukenda Sukenda ◽  
Enang Harris

Vaksin bakterin dalam bentuk protein merupakan salah satu tipe vaksin yang telah banyak dikembangkan. Protein digunakan sebagai vaksin biasanya dibuat dengan teknik inaktivasi formalin-killed. Vaksin ini biasanya lebih mudah dibuat, lebih murah, lebih stabil, dan mampu disimpan dalam waktu lama. Akan tetapi masih sedikit informasi mengenai efek perlakuan tersebut terhadap profil protein. Pada penelitian ini, untuk mengevaluasi profil protein, dilakukan inaktivasi sediaan vaksin dari isolat bakteri Aeromonas hydrophila AHL0905-2 dan Streptococcus agalactiae N14G dengan menambahkan 0,5% formalin dan 3% neutral buffer formalin (NBF) ke dalam biakan plasebo bakterin dan diinkubasi selama 24 jam. Kualitas produk vaksin ditentukan berdasarkan uji karakterisasi protein menggunakan metode Bradford dan SDS-PAGE. Hasil uji menunjukkan bahwa sediaan vaksin A. hydrophila dan S. agalactiae yang diinaktivasi dengan 3% NBF memiliki profil protein lebih variatif dibandingkan dengan sediaan vaksin yang diinaktivasi dengan 0,5% formalin. Akan tetapi, inaktivasi vaksin A. hydrophila dan S. agalactiae dengan 3% NBF menghasilkan berat total protein yang lebih rendah jika dibandingkan dengan dengan sediaan vaksin yang diinaktivasi dengan 0,5% formalin.


2008 ◽  
Vol 74 (22) ◽  
pp. 6997-7001 ◽  
Author(s):  
Suxia Guo ◽  
Mei Liu ◽  
Donghai Peng ◽  
Sisi Ji ◽  
Pengxia Wang ◽  
...  

ABSTRACT We have developed a strategy for isolating cry genes from Bacillus thuringiensis. The key steps are the construction of a DNA library in an acrystalliferous B. thuringiensis host strain and screening for the formation of crystal through optical microscopy observation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses. By this method, three cry genes—cry55Aa1, cry6Aa2, and cry5Ba2—were cloned from rice-shaped crystals, producing B. thuringiensis YBT-1518, which consists of 54- and 45-kDa crystal proteins. cry55Aa1 encoded a 45-kDa protein, cry6Aa2 encoded a 54-kDa protein, and cry5Ba2 remained cryptic in strain YBT-1518, as shown by SDS-PAGE or microscopic observation. Proteins encoded by these three genes are all toxic to the root knot nematode Meloidogyne hapla. The two genes cry55Aa1 and cry6Aa2 were found to be located on a plasmid with a rather small size of 17.7 kb, designated pBMB0228.


2008 ◽  
Vol 81 (1) ◽  
pp. 121-137 ◽  
Author(s):  
Jintana Yunyongwattanakorn ◽  
Yasuyuki Tanaka ◽  
Jitladda Sakdapipanich ◽  
Voratep Wongsasutthikul

Abstract Highly purified natural rubber (NR) was prepared by saponification of fresh latex (FL-latex) and preserved high-ammonia latex (HA-latex) in the presence of surfactant to reduce the residual proteins in resulting solid NR. Saponification of latex diluted to 30% DRC was carried out with 1–7% (w/v) sodium hydroxide at room temperature for 1–7 hr at 70 °C and coagulated with formic acid. The nitrogen content of NR obtained by coagulation of the saponified latex markedly decreased to less than 0.014% by centrifugation of the saponified latex or soaking the coagulum in aqueous sodium hydroxide solution. The nitrogenous compounds from saponified NR (SAP-NR) were extracted with sodium dodecyl sulphate (SDS) aqueous solution and subjected to SDS-Polyacrylamide Gel Electrophoresis (SDS-PAGE) analysis to check the molecular weight of extracts. The extract from SAP-NR and deproteinized NR by protease (DPNR) for comparison was subjected to the analysis of allergic protein by FIT Kit method, based on Enzyme-Linked Immunosorbent Assay (ELISA) method. No extractable protein was observed in SAP-NR, whereas DPNR contained 1.5 μg/ml proteins. The results from SDS-PAGE analysis and FIT Kit test demonstrated that NR free from allergic proteins is obtainable by saponification of FL-latex with 1.5% NaOH at 70 °C for 1 hr or at room temperature for 24 hr.


2001 ◽  
Vol 8 (2) ◽  
pp. 454-459 ◽  
Author(s):  
Mitsushi Tsujimura ◽  
Chuzo Ishida ◽  
Yasuko Sagara ◽  
Takashi Miyazaki ◽  
Koichi Murakami ◽  
...  

ABSTRACT Although a serum thermolabile β-2 macroglycoprotein (TMG) may play a role in host defense as a lectin, little is known of its related physiological functions, mainly due to a lack of appropriate methods for tracing the functions of TMG. We identified a polysaccharide fromAerococcus viridans, PSA, which reacts with TMG, and based on this finding, we developed an enzyme-linked immunosorbent assay to trace the functions of TMG. Using ethanol precipitation and DEAE-Sepharose and Sephacryl S-400 column chromatographies, we isolated PSA from cultured medium of A. viridans, and it exhibited specific binding against TMG in blood samples. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the isolated PSA showed ladder bands that implied the existence of repeating units composed of d-glucose,N-acetyl-d-glucosamine, d-mannose, and d-xylose, as confirmed by gas chromatography-mass spectrometry. SDS-PAGE and immunochemical analysis, using rabbit anti-TMG antibody, showed that PSA specifically binds solely to intact serum TMG but not to TMG heated at 56°C for 30 min, a condition under which antigenicity is lost. TMG in serum samples bound to PSA in a dose-dependent manner, and this binding was clearly suppressed by addition of PSA. These observations indicate that PSA is a useful adsorbent to TMG and can be used to develop appropriate methods for tracing the functions of TMG.


2003 ◽  
Vol 69 (7) ◽  
pp. 4111-4115 ◽  
Author(s):  
LanNa Lee ◽  
Deepak Saxena ◽  
G. Stotzky

ABSTRACT Bacillus thuringiensis subsp. israelensis produces parasporal insecticidal crystal proteins (ICPs) that have larvicidal activity against some members of the order Diptera, such as blackflies and mosquitoes. Hydrolysis of the ICPs in the larval gut results in four major proteins with a molecular mass of 27, 65, 128, and 135 kDa. Toxicity is caused by synergistic interaction between the 25-kDa protein (proteolytic product of the 27-kDa protein) and one or more of the higher-molecular-mass proteins. Equilibrium adsorption of the proteins on the clay minerals montmorillonite and kaolinite, which are homoionic to various cations, was rapid (<30 min for maximal adsorption), increased with protein concentration and then reached a plateau (68 to 96% of the proteins was adsorbed), was significantly lower on kaolinite than on montmorillonite, and was not significantly affected by the valence of the cation to which the clays were homoionic. Binding of the toxins decreased as the pH was increased from 6 to 11, and there was 35 to 66% more binding in phosphate buffer at pH 6 than in distilled water at pH 6 or 7.2. Only 2 to 12% of the adsorbed proteins was desorbed by two washes with water; additional washings desorbed no more toxins, indicating that they were tightly bound. Formation of clay-toxin complexes did not alter the structure of the proteins, as indicated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the equilibrium supernatants and desorption washes and by dot blot enzyme-linked immunosorbent assay of the complexes, which was confirmed by enhanced chemiluminescence Western blot analysis. Free and clay-bound toxins resulted in 85 to 100% mortality of the mosquito Culex pipiens. Persistence of the bound toxins in nonsterile water after 45 days was significantly greater (mortality of 63% ± 12.7%) than that of the free toxins (mortality of 25% ± 12.5%).


2018 ◽  
Vol 10 (1) ◽  
pp. 33-45
Author(s):  
Syed Abid Ali ◽  
Fozia Humayun ◽  
Iqra Munir ◽  
Shakil Ahmad ◽  
Zarrien Ayub ◽  
...  

Objective: The present study was conducted to investigate the biomass assessment, morphological and molecular identification, nutritive status and biochemical characterization of three major Thais species (T. bufo, T. hippocastanum and T. rudolphi) from the Sindh Coast, Pakistan. Methods: Samples were collected from Buleji and Paradise Point at the Sindh Coast. Species were identified morphologically as well as genetically by amplifying two mitochondrial 16S rDNA & Cytochrome Oxidase I (COI) and one nuclear (Histone H3) genes. Shell microstructure and chemistry were also studied by scanning electron microscopy and Energy Dispersive X-ray spectrometry (EDX). The body muscle was dissected and used for nutritional composition determination such as estimation of total protein, carbohydrates, lipids, protein fingerprinting by Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Size-Exclusion - Fast Protein Liquid Chromatography (SEC-FPLC), amino acid and fatty acid analysis. Results: Nutritionally, the total protein was found to be the major content followed by carbohydrate and lipid in the three Thais sp. The presence of medicinally important hemocyanin as abundant hemolymph protein was confirmed via SDS-PAGE and SEC FPLC. Nine different types of fatty acids and a high concentration of essential amino acids were also determined. Conclusion: Our findings suggest that Thais sp. are nutritionally rich and can be consumed as a valuable marine resource to overcome the malnutrition problem in developing countries.


2021 ◽  
Vol 44 (1) ◽  
pp. 40-45
Author(s):  
Chonvara Chalermrujinanant ◽  
Panwadee Pluangnooch ◽  
Kitipong Soontrapa

Background: Allergen extracts have been applied to treat allergic diseases. Accordingly, a housefly (Musca domestica) extract is commonly used to treat patients severely allergic to housefly. Objective: To evaluate 3 common methods, including grinding, sonication, and homogenization, for effective preparation of housefly allergen extracts. Methods: Housefly allergens were extracted from Musca domestica using 3 different methods, including grinding, sonication, and homogenization. Protein concentrations and profiles in the extracts were determined by Bradford assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), respectively. Results: The protein concentrations of the extracts prepared by grinding (mean [SD], 911.3 [159.7] µg/µL) and sonication (mean [SD], 905.7 [188.6] µg/µL) as measured by Bradford assay were significantly higher than those prepared by homogenization (mean [SD], 674.5 [60.0] µg/µL). Moreover, SDS-PAGE showed more protein bands in the extracts prepared using grinding and sonication compared to those prepared using homogenization. Conclusions: In comparison to homogenization, both grinding and sonication methods are superior ways to prepare housefly allergen extracts as evidenced by the higher quantities and composition of proteins.  


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