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Rees PA, Lowy RJ. Optimizing reduction of western blotting analytical variations: Use of replicate test samples, multiple normalization methods, and sample loading positions. Anal Biochem 2023:115198. [PMID: 37302777 DOI: 10.1016/j.ab.2023.115198] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/23/2023] [Accepted: 05/27/2023] [Indexed: 06/13/2023]
Abstract
Western blot (WB) analysis is widely used, but obtaining consistent results can be problematic, especially when using multiple gels. This study examines WB performance by explicitly applying a method commonly used to test analytical instrumentation. Test samples were lysates from RAW 264.7 murine macrophages treated with LPS to activate MAPK and NF-kB signaling targets. Samples from the pooled cell lysates placed in every lane on multiple gels were analyzed by WBs for levels of p-ERK, ERK, IkBβ and non-target protein. Different normalization methods and sample groupings were applied to the density values and the resulting coefficients of variation (CV) and ratios of maximal to minimal values (Max/Min) were compared. Ideally with identical sample replicates the CVs would be 0 and the Max/Min 1; deviation indicating introduction of variability by the WB process. Common normalizations to reduce analytical variance, total lane protein, % Control, and p-ERK/ERK ratios, did not have the lowest CVs or Max/Min values. Normalization using the sum of target protein values combined with analytical replication most effectively reduced variability, resulting CV and Max/Min values as low as 5-10% and 1.1. These methods should allow reliable interpretation of complex experiments that require samples to be placed on multiple gels.
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Affiliation(s)
- Phyllis A Rees
- Scientific Research Department, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - R Joel Lowy
- Scientific Research Department, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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2
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Wang JL, Xu ZT, Zhan L, Liao M, Xu CJ. Heat-induced antigen retrieval utilizing modified Tris-EDTA buffer for reprobing of Western blots on nitrocellulose paper. Anal Biochem 2023; 672:115179. [PMID: 37150424 DOI: 10.1016/j.ab.2023.115179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/20/2023] [Accepted: 05/01/2023] [Indexed: 05/09/2023]
Abstract
The development of heat-induced antigen retrieval technologies with Tris-EDTA buffer has dramatically improved immunostaining of specific antigens for routine immunohistochemical detection (Krenacs et al., 2010) [1]. However, little evidence exists on whether heat-Induced antigen retrieval utilizing Tris-EDTA buffer can strip western blot (WB) membranes and allow sequential reprobing. Here, we serendipitously discover that ∼95 °C Tris-EDTA buffer with 0.01% Tween 20 could repeatedly strip the Nitrocellulose membranes (NC). After electroblotting, NC blots were soaked into Tris-EDTA stripping buffer (∼95 °C, 10-25min) and we could perform at least five rounds (the following antibodies used: Vinculin, Atg7, Caspase-3, UBA5, JNK and ERK1/2) stripping in sequential chemiluminescent detections. The NC membranes also show clear western signals and background without losing transferred proteins during the reprobing process of WB. Hence, this study report additional new roles of the heat-Induced antigen retrieval Tris-EDTA buffer with 0.01% Tween 20. The method is simpler, more affordable and harmless for the nitrocellulose paper, which will be helpful for effective reprobing in western blotting applications.
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Affiliation(s)
- Jun-Ling Wang
- Center for Reproductive Medicine, Affiliated Hospital 1 of Wenzhou Medical University, Wenzhou, Zhejiang, 325000, PR China.
| | - Ze-Ting Xu
- Department of Histology & Embryology, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, PR China.
| | - Ling Zhan
- School of 1st Clinical Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, PR China.
| | - Min Liao
- Department of Histology & Embryology, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, PR China.
| | - Chao-Jin Xu
- Department of Histology & Embryology, School of Basic Medical Science, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, PR China.
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3
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Immunization with Hypoallergens of shrimp allergen tropomyosin inhibits shrimp tropomyosin specific IgE reactivity. PLoS One 2014; 9:e111649. [PMID: 25365343 PMCID: PMC4218792 DOI: 10.1371/journal.pone.0111649] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 09/29/2014] [Indexed: 02/06/2023] Open
Abstract
Designer proteins deprived of its IgE-binding reactivity are being sought as a regimen for allergen-specific immunotherapy. Although shrimp tropomyosin (Met e 1) has long been identified as the major shellfish allergen, no immunotherapy is currently available. In this study, we aim at identifying the Met e 1 IgE epitopes for construction of hypoallergens and to determine the IgE inhibitory capacity of the hypoallergens. IgE-binding epitopes were defined by three online computational models, ELISA and dot-blot using sera from shrimp allergy patients. Based on the epitope data, two hypoallergenic derivatives were constructed by site-directed mutagenesis (MEM49) and epitope deletion (MED171). Nine regions on Met e 1 were defined as the major IgE-binding epitopes. Both hypoallergens MEM49 and MED171 showed marked reduction in their in vitro reactivity towards IgE from shrimp allergy patients and Met e 1-sensitized mice, as well as considerable decrease in induction of mast cell degranulation as demonstrated in passive cutaneous anaphylaxis assay. Both hypoallergens were able to induce Met e 1-recognizing IgG antibodies in mice, specifically IgG2a antibodies, that strongly inhibited IgE from shrimp allergy subjects and Met e 1-sensitized mice from binding to Met e 1. These results indicate that the two designer hypoallergenic molecules MEM49 and MED171 exhibit desirable preclinical characteristics, including marked reduction in IgE reactivity and allergenicity, as well as ability to induce blocking IgG antibodies. This approach therefore offers promises for development of immunotherapeutic regimen for shrimp tropomyosin allergy.
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4
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Supported molecular matrix electrophoresis: a new membrane electrophoresis for characterizing glycoproteins. Methods Mol Biol 2014; 1200:327-33. [PMID: 25117247 DOI: 10.1007/978-1-4939-1292-6_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Protein blotting is often used for identification and characterization of proteins on a membrane to which proteins separated by gel electrophoresis are transferred. The transferring process is sometimes problematic, in particular, for mucins and proteoglycans. Here, we describe a novel membrane electrophoresis technique, termed supported molecular matrix electrophoresis (SMME), in which a porous polyvinylidene difluoride (PVDF) membrane filter is used as the separation support. Proteins separated by this method can be immunoblotted without any transferring procedures.
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Matsuno YK, Dong W, Yokoyama S, Yonezawa S, Saito T, Gotoh M, Narimatsu H, Kameyama A. Improved method for immunostaining of mucin separated by supported molecular matrix electrophoresis by optimizing the matrix composition and fixation procedure. Electrophoresis 2011; 32:1829-36. [DOI: 10.1002/elps.201000608] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 03/17/2011] [Accepted: 03/23/2011] [Indexed: 01/08/2023]
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6
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Liu J, Liu X, Baeyens WRG, Delanghe JR, Ouyang J. A Novel Probe Au(III) for Chemiluminescent Image Detection of Protein Blots on Nitrocellulose Membranes. J Proteome Res 2008; 7:1884-90. [DOI: 10.1021/pr700616u] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jia Liu
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium, and Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium
| | - Xia Liu
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium, and Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium
| | - Willy R. G. Baeyens
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium, and Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium
| | - Joris R. Delanghe
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium, and Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium
| | - Jin Ouyang
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium, and Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium
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7
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Antharavally BS, Carter B, Bell PA, Krishna Mallia A. A high-affinity reversible protein stain for Western blots. Anal Biochem 2004; 329:276-80. [PMID: 15158487 DOI: 10.1016/j.ab.2004.02.049] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Indexed: 11/25/2022]
Abstract
We describe a reversible staining technique, using MemCode, a reversible protein stain by which proteins can be visualized on nitrocellulose and polyvinylidine fluoride (PVDF) membranes without being permanently fixed to the membrane itself. This allows subsequent immunoblot analysis of the proteins to be performed. The procedure is applicable only to protein blots on nitrocellulose and PVDF membranes. MemCode is a reversible protein stain composed of copper as a part of an organic complex that interacts noncovalently with proteins. MemCode shows rapid protein staining, taking 30s to 1 min for completion. The method is simple and utilizes convenient application conditions that are compatible with the matrix materials and the protein. The stain is more sensitive than any previously described dye-based universal protein staining system. The turquoise-blue-stained protein bands do not fade with time and are easy to photograph compared to those stained with Ponceau S. Absorbance in the blue region of the spectrum offers good properties for photo documentation and avoids interference from common biological chromophores. The stain on the protein is easily reversible in 2 min for nitrocellulose membrane and in 10 min for PVDF membrane with MemCode stain eraser. The stain is compatible with general Western blot detection systems, and membrane treatment with MemCode stain does not interfere with conventional chemiluminescent or chromogenic detection using horseradish peroxide and alkaline phosphatase substrates. The stain is also compatible with N-terminal sequence analysis of proteins.
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Affiliation(s)
- Babu S Antharavally
- Pierce Biotechnology, Inc., Research and Development, 3747 N. Meridian Road, P.O. Box 117, Rockford, IL 61105, USA.
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8
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Di Cristo C, Paolucci M, Iglesias J, Sanchez J, Di Cosmo A. Presence of two neuropeptides in the fusiform ganglion and reproductive ducts of Octopus vulgaris: FMRFamide and gonadotropin-releasing hormone (GnRH). THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2002; 292:267-76. [PMID: 11857460 DOI: 10.1002/jez.90000] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have found evidence of FMRFamide-like and cGnRH-I-like immunoreactivity in the central nervous system (CNS) and in the reproductive ducts of both female and male cephalopod Octopus vulgaris. Cell bodies and fibers were immunolocalized in the fusiform ganglion from which the nerves that reach the female and male reproductive ducts arise. FMRFamide-like and cGnRH-I-like immunoreactive nerve endings were present in the oviduct, and in the oviducal gland of the female and in the seminal vesicle of the male. The GnRH-like peptide from the reproductive ducts has been partially characterized by HPLC. The retention time of the Octopus vulgaris GnRH-like peptide was similar to the retention time of cGnRH-I. Based on these observations we suggest that FMRFamide-like and a novel GnRH-like peptide are involved in the control of reproductive ducts of Octopus vulgaris. One possibility is that the peptides affect gamete transport. Another possibility is that they regulate secretory products such as mucus and mucilaginous substances from the oviducal gland and the seminal vesicle. Our data provide further evidence to support the hypothesis of the existence of a central and peripheral peptidergic control of reproduction of Octopus vulgaris.
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Affiliation(s)
- Carlo Di Cristo
- Faculty of Science, University of Sannio, 82100 Benevento, Italy
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9
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Patton WF. A thousand points of light: the application of fluorescence detection technologies to two-dimensional gel electrophoresis and proteomics. Electrophoresis 2000; 21:1123-44. [PMID: 10786886 DOI: 10.1002/(sici)1522-2683(20000401)21:6<1123::aid-elps1123>3.0.co;2-e] [Citation(s) in RCA: 198] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
As proteomics evolves into a high-throughput technology for the study of global protein regulation, new demands are continually being placed upon protein visualization and quantitation methods. Chief among these are increased detection sensitivity, broad linear dynamic range and compatibility with modern methods of microchemical analyses. The limitations of conventional protein staining techniques are increasingly being encountered as high sensitivity electrophoresis methods are interfaced with automated gel stainers, image analysis workstations, robotic spot excision instruments, protein digestion work stations, and mass spectrometers. Three approaches to fluorescence detection of proteins in two-dimensional (2-D) gels are currently practiced: covalent derivatization of proteins with fluorophores, intercalation of fluorophores into the sodium dodecyl sulfate (SDS) micelle, and direct electrostatic interaction with proteins by a Coomassie Brilliant Blue-type mechanism. This review discusses problems encountered in the analysis of proteins visualized with conventional stains and addresses advances in fluorescence protein detection, including immunoblotting, as well as the use of charge-coupled device (CCD) camera-based and laser-scanner-based image acquisition devices in proteomics.
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Affiliation(s)
- W F Patton
- Molecular Probes, Inc., Eugene, OR 97402, USA.
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10
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Patton WF. A thousand points of light: The application of fluorescence detection technologies to two-dimensional gel electrophoresis and proteomics. Electrophoresis 2000. [DOI: 10.1002/(sici)1522-2683(20000401)21:6%3c1123::aid-elps1123%3e3.0.co;2-e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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11
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Berggren K, Steinberg TH, Lauber WM, Carroll JA, Lopez MF, Chernokalskaya E, Zieske L, Diwu Z, Haugland RP, Patton WF. A luminescent ruthenium complex for ultrasensitive detection of proteins immobilized on membrane supports. Anal Biochem 1999; 276:129-43. [PMID: 10603235 DOI: 10.1006/abio.1999.4364] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
SYPRO Ruby protein blot stain provides a sensitive, gentle, fluorescence-based method for detecting proteins on nitrocellulose or polyvinylidene difluoride (PVDF) membranes. SYPRO Ruby dye is a permanent stain composed of ruthenium as part of an organic complex that interacts noncovalently with proteins. Stained proteins can be excited by ultraviolet light of about 302 nm or with visible light of about 470 nm. Fluorescence emission of the dye is approximately 618 nm. The stain can be visualized using a wide range of excitation sources utilized in image analysis systems including a UV-B transilluminator, 488-nm argon-ion laser, 532-nm yttrium-aluminum-garnet (YAG) laser, blue fluorescent light bulb, or blue light-emitting diode (LED). The detection sensitivity of SYPRO Ruby protein blot stain (0.25-1 ng protein/mm(2)) is superior to that of amido black, Coomassie blue, and india ink staining and nearly matches colloidal gold staining. SYPRO Ruby protein blot stain visualizes proteins more rapidly than colloidal gold stain and the linear dynamic range is more extensive. Unlike colloidal gold stain, SYPRO Ruby protein blot stain is fully compatible with subsequent biochemical applications including colorimetric and chemiluminescent immunoblotting, Edman-based sequencing and mass spectrometry.
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Affiliation(s)
- K Berggren
- Molecular Probes, Inc., Eugene, Oregon 97402, USA
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12
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Abstract
A simple, sensitive, rapid (3 min), and highly reproducible solid-phase assay for the detection of proteins in the low nanogram range (4 ng) is described. The assay is based on differential Ponceau S staining of the protein spots on nitrocellulose and quantification of the protein-dye complexes on lubricated membranes using a densitometer. The dye solution used for protein staining contained 0.1% Ponceau S in 15% phosphoric acid and 10% ethanol. Proteins were directly spotted onto pre-Ponceau S-stained nitrocellulose membranes, cross-linked with glutaraldehyde, rinsed in NaOH, restained with Ponceau S, and finished by rinsing in acid water at pH 3. Dry membranes were lubricated with mineral oil to achieve brightness of the colored spots before scanning with a densitometer at 560 nm. The assay shows tolerance to extreme acidic and basic buffer conditions and no significant protein-to-protein variations were observed. The effects of detergent contaminants and various other reagents such as polyethylene glycol, mercaptoethanol, and urea were also tested in the assay. The nonionic detergent, digitonin, and the anionic detergent, sodium dodecyl sulfate, up to 1%, and Triton X-100 up to 0.25% do not interfere with the assay. Efficacy of the assay was tested for five different proteins and the sensitivity was compared with the most widely used method of Bradford's.
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Affiliation(s)
- T Morçöl
- Ben-Abraham Technologies Inc., 4600 Highlands Parkway, Suites A & B, Smyrna, Georgia 30082, USA
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13
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Nokihara K. Procedures leading to primary structure determination of proteins in complex mixtures by gel electrophoresis and modern micro-scale analyses. Anal Chim Acta 1998. [DOI: 10.1016/s0003-2670(98)00347-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Abstract
A highly sensitive dot immunoblot assay (DIA) for the detection and quantitative measurement of small peptides in single cells is presented. This DIA protocol is simple, rapid, and produces no radioactive waste. Its femtomole sensitivity is 100 fold greater than previously described DIAs. This DIA method is sufficiently sensitive to allow reliable peptide measurements to be obtained from a single cell in a manner than is faster and easier than other peptide detection procedures. This method can also be used for several other purposes, including assessing antibody specificity and peptide quantification.
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Affiliation(s)
- P K Loi
- Institute of Neuroscience, University of Oregon, Eugene 97403, USA.
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15
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Santama N, Li KW, Geraerts WP, Benjamin PR, Burke JF. Post-translational processing of the alternative neuropeptide precursor encoded by the FMRFamide gene in the pulmonate snail Lymnaea stagnalis. Eur J Neurosci 1996; 8:968-77. [PMID: 8743745 DOI: 10.1111/j.1460-9568.1996.tb01584.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The neuropeptide gene encoding FMRFamide-like peptides in the pulmonate mollusc Lymnaea is subject to alternative splicing that generates cell-specific expression of distinct sets of peptides in the CNS. In this paper, we analyse the post-translational processing of the alternative protein precursor encoded by the exon I, III-V transcript (type 2 transcript). We raised anti-peptide antisera specific to distinct segments of the precursor in order to address the pattern of endoproteolytic cleavages, specifically around the tetrabasic site RRKR. We first showed that not all peptides predicted by the precursor structure are generated as final steady-state products. We then identified a novel peptide by biochemical purification, amino acid sequencing and mass spectrometry- the 35 amino acid SDPFFRFGKQQVATDDSGELDDEILSRVSDDDKNI, which we termed the acidic peptide, previously not predicted on the basis of the precursor structure. This novel peptide, abundant in the snail brain (0.7 pmol per central nervous system), includes the N-terminal sequence SDPFFRF, which was previously considered to be a variant of the known heptapeptide SDPFLRFamide, also encoded within the same protein precursor. We showed by in situ hybridization and immunocytochemistry that the acidic peptide is produced in all cells that transcribe type 2 FMRFamide mRNA. We mapped the expression of this novel peptide in the CNS and localized it mainly in three identifiable neuronal clusters - the E, F and B groups of cells - and some additional neurons, all situated in three of the eleven central ganglia. Immunoreactive neurons included the single identifiable visceral white interneuron (VWI or VD4), a key cell of the cardiorespiratory network.
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Affiliation(s)
- N Santama
- Sussex Centre for Neuroscience, School of Biological Sciences, University of Sussex, Brighton BN1 9QG, UK
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16
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Van Golen FA, Li KW, De Lange RP, Van Kesteren RE, Van Der Schors RC, Geraerts WP. Co-localized neuropeptides conopressin and ALA-PRO-GLY-TRP-NH2 have antagonistic effects on the vas deferens of Lymnaea. Neuroscience 1995; 69:1275-87. [PMID: 8848113 DOI: 10.1016/0306-4522(95)00311-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We examined functional aspects of co-localization of neuropeptides involved in the regulation of male copulation behaviour in the simultaneous hermaphrodite snail Lymnaea stagnalis. The copulation behaviour is controlled by several types of peptidergic neurons that include a cluster of neurons in the anterior lobe of the right cerebral ganglion. All anterior lobe neurons express the gene encoding Ala-Pro-Gly-Trp-NH2 (APGWamide), and a subset of neurons also express the vasopressin-related conopressin gene. Immunocytochemical and peptide chemical experiments show that both APGWamide and conopressin are transported to the penis complex and the vas deferens via the penis nerve. Co-localization of the two peptides was also observed in some, but not all, axon bundles that run along the vas deferens. APGWamide and conopressin were structurally identified from the penis complex with vas deferens. Conopressin excites the vas deferens in vitro, whereas APGWamide inhibits the excitatory effects of conopressin, both in a dose-dependent fashion. We propose that the antagonistic effects of these peptides on the vas deferens underlie its peristalsis. Thus, these peptides play an important role in the control of ejaculation of semen during copulation.
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Affiliation(s)
- F A Van Golen
- Graduate School Neurosciences Amsterdam, Research Institute Neurosciences Vrije Universiteit, Netherlands
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17
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Santama N, Wheeler CH, Skingsley DR, Yeoman MS, Bright K, Kaye I, Burke JF, Benjamin PR. Identification, distribution and physiological activity of three novel neuropeptides of Lymnaea: EFLRlamide and pQFYRlamide encoded by the FMRFamide gene, and a related peptide. Eur J Neurosci 1995; 7:234-46. [PMID: 7757260 DOI: 10.1111/j.1460-9568.1995.tb01059.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We are interested in analysing the detailed modulation of defined neuronal systems by multiple neuropeptides encoded in the FMRFamide locus of the snail Lymnaea. Cloning of the FMRFamide gene has predicted the existence of two novel peptides previously unknown from biochemical analysis, the pentapeptides EFLRlamide and QFYRlamide. These peptides may form part of a new family of peptides sharing the sequence motif -FXRlamide. In this paper we adopt a novel approach to first identify and characterize -FXRlamide-like peptides in extracts from the central nervous system of Lymnaea. By a combination of high-performance liquid chromatography (HPLC) and continuous-flow fast atom bombardment mass spectrometry, we identify three novel peptides: EFLRlamide, pQFYRlamide and pQFLRlamide. The first two are those predicted in exon II of the FMRFamide locus whereas the last is, interestingly, a product which cannot be derived from post-translational modification of the predicted peptides but must be encoded by as yet unidentified nucleotide sequences. A specific antibody raised to EFLRlamide, and immunoreactive to all three peptides, revealed EFLRlamide-like expression throughout the central nervous system in the same cells where exon II is transcribed and the peptide SEEPLY (a post-translational product of exon II) was localized. Additional cells, however, were also identified. Immunoreactivity was mapped in a number of identified neurons in the central nervous system, including two heart cardioexcitatory motoneurons, the Ehe cells (E heart excitors of the visceral ganglion) and penial motoneurons in the right cerebral ganglion. The peripheral tissues (heart and penial complex) that these respective classes of neurons innervate also exhibited EFLRlamide immunoreactivity. The central and peripheral localization of EFLRlamide-like immunoreactivity suggested that EFLRlamide/pQFYRlamide may have an important physiological role in both these peripheral systems as well as in the central nervous system. This was confirmed by physiological experiments that showed that EFLRlamide and pQFYRlamide inhibited many central neurons and in particular the Bgp neurons in the right parietal ganglion. EFLRlamide had complex biphasic effects on the frequency of heart-beat: an initial inhibitory response was followed by a long-lasting increase in the rate of beating. Taken together with earlier work, this study now completes the analysis and localization of the full set of post-translational products of the FMRFamide precursor in Lymnaea and supplies further evidence towards the characterization of the physiological systems which such peptides may modulate in concert.
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Affiliation(s)
- N Santama
- Sussex Centre for Neuroscience, School of Biological Sciences, University of Sussex, Brighton, UK
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18
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Santama N, Wheeler CH, Burke JF, Benjamin PR. Neuropeptides myomodulin, small cardioactive peptide, and buccalin in the central nervous system of Lymnaea stagnalis: purification, immunoreactivity, and artifacts. J Comp Neurol 1994; 342:335-51. [PMID: 8021339 DOI: 10.1002/cne.903420303] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The neuropeptides myomodulin, small cardioactive peptide (SCP), and buccalin are widely distributed in the phylum Mollusca and have important physiological functions. Here, we describe the detailed distribution of each class of peptide in the central nervous system (CNS) of the snail Lymnaea stagnalis by the use of immunocytochemical techniques combined with dye-marking of electrophysiologically identified neurons. We report the isolation and structural characterization of a Lymnaea myomodulin, PMSMLRLamide, identical to myomodulin A of Aplysia californica. Myomodulin immunoreactivity was localized in all 11 ganglia, in their connectives, and in peripheral nerves. In many cases, myomodulin immunoreactivity appeared localized in neuronal clusters expressing FMRFamide-like peptides, but also in a large number of additional neurons. Double-labelling experiments demonstrated myomodulin immunoreactivity in the visceral white interneuron, involved in regulation of cardiorespiration. SCP-like immunoreactivity also appeared in all ganglia, and double-labelling experiments revealed that in many locations it was specifically associated with clusters expressing distinct exons of the FMRFamide gene that are differentially expressed in the CNS. Characterization of the two types of SCP-antisera used in this study, however, suggested that they cross-reacted with both FMRFamide and N-terminally extended FMRFamide-like peptides. Selective preadsorption with these cross-reacting peptides resulted in elimination of the widespread staining and retention of bona fide SCP immunoreactivity in the buccal and pedal ganglia only. Buccalin immunoreactivity was limited to the buccal and pedal ganglia. It did not coincide with the distribution of either myomodulin or SCP. Most immunoreactive clusters were found in the pedal ganglia.
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Affiliation(s)
- N Santama
- Sussex Centre for Neuroscience, School of Biological Sciences, University of Sussex, Brighton, United Kingdom
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Hoffman WL, Jump AA, Ruggles AO, Kelly PJ. Antibodies bound to nitrocellulose in acidic buffers retain biological activity. Electrophoresis 1993; 14:886-91. [PMID: 8223398 DOI: 10.1002/elps.11501401141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This report compares the binding of proteins to nitrocellulose membranes in acidic buffers (pH 2 and 3) with binding in neutral buffer (pH 7). Initially, similar amounts of antibodies and other proteins bound to the nitrocellulose membrane in both acidic and neutral buffers. However, the susceptibility of individual proteins to displacement (stripping) from the membrane by the milk blocking agent depended on the pH of the buffer used to bind the proteins to the membrane. Most proteins that bound to nitrocellulose in acidic buffers were relatively resistant to milk-stripping compared to proteins bound in pH 7 buffer. Acid-binding of proteins to nitrocellulose also decreased the amount of protein that was stripped from the nitrocellulose membrane when Tween 20 was included in the washing buffer. After correcting for the amount of antibody remaining on the membrane after the milk block, it was found that acid-bound antibodies were unchanged in biological activity when compared with the same antibodies bound at neutral pH. These results suggest that acid-binding of proteins could increase the sensitivity of nitrocellulose membrane assays that use milk and/or Tween 20.
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Affiliation(s)
- W L Hoffman
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
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20
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Santama N, Li KW, Bright KE, Yeoman M, Geraerts WP, Benjamin PR, Burke JF. Processing of the FMRFamide precursor protein in the snail Lymnaea stagnalis: characterization and neuronal localization of a novel peptide, 'SEEPLY'. Eur J Neurosci 1993; 5:1003-16. [PMID: 7904219 DOI: 10.1111/j.1460-9568.1993.tb00952.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In the pulmonate snail Lymnaea stagnalis, FMRFamide-like neuropeptides are encoded by a multi-exon genomic locus which is subject to regulation at the level of mRNA splicing. We aim to understand the post-translational processing of one resulting protein precursor encoding the tetrapeptide FMRFamide and a number of other putative peptides, and determine the distribution of the final peptide products in the central nervous system (CNS) and periphery of Lymnaea. We focused on two previously unknown peptide sequences predicted by molecular cloning to be encoded in the tetrapeptide protein precursor consecutively, separated by the tetrabasic cleavage site RKRR. Here we report the isolation and structural characterization of a novel non-FMRFamide-like peptide, the 22 amino acid peptide SEQPDVDDYLRDVVLQSEEPLY. The novel peptide is colocalized with FMRFamide in the CNS in a number of identified neuronal systems and their peripheral motor targets, as determined by in situ hybridization and immunocytochemistry. Its detection in heart excitatory motoneurons and in nerve fibres of the heart indicated that the novel peptide may play a role, together with FMRFamide, in heart regulation in the snail. The second predicted peptide, STEAGGQSEEMTHRTA (16 amino acids), was at very low abundance in the CNS and was only occasionally detected. Our current findings, suggestive of a distinct pattern of post-translational processing, allowed the reassessment of a previously proposed hypothesis that the two equivalent sequences in the Aplysia FMRFamide gene constitute a molluscan homologue of vertebrate corticotrophin releasing factor-like peptides.
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Affiliation(s)
- N Santama
- Sussex Centre for Neuroscience, School of Biological Sciences, University of Sussex, Brighton, UK
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21
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Li KW, Geraerts WP, Ebberink RH, Joosse J. Purification and sequencing of molluscan insulin-related peptide I (MIP I) from the neuroendocrine light green cells of Lymnaea stagnalis. Mol Cell Endocrinol 1992; 85:141-50. [PMID: 1526314 DOI: 10.1016/0303-7207(92)90133-q] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The body growth controlling cerebral neuroendocrine light green cells of the freshwater snail, Lymnaea stagnalis, express various members of a gene family encoding different though related prepromolluscan insulin-related peptides. In the present study, molluscan insulin-related peptide I (MIP I) together with the corresponding connecting peptide, C alpha peptide, have been isolated and structurally identified. MIP I is a heterodimer of A and B chains bonded by disulphide bridges. Two isoforms of MIP I could be discerned. Mass spectrometry revealed that of one form both the A and B chains have N-terminal pyroglutamyl residues, whereas of the other form only the B chain has such residues. After removal of the pyroglutamyl residues with pyroglutamate aminopeptidase, followed by disulphide bond cleavage and pyridylethylation of cysteine residues, the sequences of MIP I have been determined using Edman degradation as: A chain: (p)QGTTNIVCECCMKPCTLSELRQYCP; B chain: pQPSACNINDRPHRRGVCGSALADLVDPACSSSNGPA. The C alpha peptide has also been isolated and its sequence was determined as NAETDLDDPLRNIKLSSESALTYLY. These sequences are in agreement with those predicted by a cDNA sequence encoding preproMIP I, with the exception that the two C-terminal amino acids of the B chain are posttranslationally removed.
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Affiliation(s)
- K W Li
- Department of Biology, Vrije Universiteit, Amsterdam, Netherlands
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22
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Patterson SD, Hess D, Yungwirth T, Aebersold R. High-yield recovery of electroblotted proteins and cleavage fragments from a cationic polyvinylidene fluoride-based membrane. Anal Biochem 1992; 202:193-203. [PMID: 1377888 DOI: 10.1016/0003-2697(92)90227-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this report we describe the use of a novel, experimental, polyvinylidene fluoride-based membrane with a cationic surface for the isolation by electroblotting of small amounts of proteins separated by gel electrophoresis for further characterization by protein fragmentation for internal sequence analysis. The membrane is characterized by a surface that mediates primarily ionic protein/membrane interactions and that allows the recovery of adsorbed proteins at high yields under relatively mild conditions. In electroblotting experiments, the novel membrane has a binding capacity that is at least equivalent to that of standard polyvinylidene fluoride membranes and is compatible with both chemical and enzymatic fragmentation of blotted proteins in situ. Intact electroblotted proteins, or fragments thereof, were eluted at high yields. Further structural analysis is demonstrated using reverse-phase high-performance liquid chromatography or gel electrophoresis to separate cleavage fragments for either pulsed-liquid- or solid-phase automated sequence analysis.
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23
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Christiansen J, Houen G. Comparison of different staining methods for polyvinylidene difluoride membranes. Electrophoresis 1992; 13:179-83. [PMID: 1375557 DOI: 10.1002/elps.1150130137] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Several new staining methods for polyvinylidene difluoride membranes, including mercurochrome, silver and dimethylaminoazobenzene isothiocyanate staining were compared with Coomassie Brilliant Blue and gold staining. Of these, Coomassie was most versatile and completely compatible with ensuing microsequencing, immunostaining or other visualization methods, while gold and silver staining were more sensitive. Mercurochrome allows selective detection of sulfhydryl-containing proteins while dimethylaminoazobenzene isothiocyanate staining may allow quantitation of sequenceable protein.
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Affiliation(s)
- J Christiansen
- Institute of Biochemical Genetics, University of Copenhagen, Denmark
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24
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Kerkhoven RM, Croll RP, Ramkema MD, Van Minnen J, Bogerd J, Boer HH. The VD1/RPD2 neuronal system in the central nervous system of the pond snail Lymnaea stagnalis studied by in situ hybridization and immunocytochemistry. Cell Tissue Res 1992; 267:551-9. [PMID: 1315219 DOI: 10.1007/bf00319378] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
VD1 and RPD2 are two giant neuropeptidergic neurons in the central nervous system (CNS) of the pond snail Lymnaea stagnalis. We wished to determine whether other central neurons in the CNS of L. stagnalis express the VD1/RPD2 gene. To this end, in situ hybridization with the cDNA probe of the VD1/RPD2 gene and immunocytochemistry with antisera specific to VD1 and RPD2 (the alpha 1-antiserum, Mab4H5 and ALMA 6) and to R15 (the alpha 1 and 16-mer antisera) were performed on alternate tissue sections. A VD1/RPD2 neuronal system comprising three classes of neurons (A1-A3) was found. All neurons of the system express the gene. Division into classes is based on immunocytochemical characteristics. Class A1 neurons (VD1 and RPD2) immunoreact with the alpha 1-antiserum, Mab4H5 and ALMA 6. Class A2 neurons (1-5 small and 1-5 medium sized neurons in the visceral and right parietal ganglion, and two clusters of small neurons and 5 medium-sized neurons in the cerebral ganglia) immunoreact with the alpha 1-antiserum and Mab4H5, but not with ALMA 6. Class A3 neurons (3-4 medium-sized neurons and a cluster of 4-5 small neurons located in the pedal ganglion) immunoreact with the alpha 1-antiserum only. All neurons of the system are immunonegative to the R15 antisera. The observations suggest that the neurons of the VD1/RPD2 system produce different sets of neuropeptides. A group of approximately 15 neurons (class B), scattered in the ganglia, immunostained with one or more of the antisera, but did not react with the cDNA probe in in situ hybridization.
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Affiliation(s)
- R M Kerkhoven
- Department of Organismic Zoology, Faculty of Biology, Amsterdam, The Netherlands
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25
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Hoffman WL, Jump AA, Kelly PJ, Ruggles AO. Binding of antibodies and other proteins to nitrocellulose in acidic, basic, and chaotropic buffers. Anal Biochem 1991; 198:112-8. [PMID: 1789412 DOI: 10.1016/0003-2697(91)90514-t] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This report compares the binding of proteins to nitrocellulose membranes in acidic buffers (pH 2 and 3) with binding in neutral buffer (pH 7), basic buffers (pH 12 and 13), 8 M urea (pH 2, 3, and 7), and 6 M guanidine hydrochloride (pH unadjusted). Initially, similar amounts of antibodies and other proteins bound to the nitrocellulose membrane in all of these buffers and solvents. However, the susceptibility of individual proteins to displacement (stripping) from the membrane by the milk blocking agent depended on both the pH and the type of buffer or solvent used to bind the proteins to the membrane. Most proteins that were bound to nitrocellulose in acidic buffers were relatively resistant to milk stripping compared to proteins bound in pH 7 buffer. After correction for the amount of antibody remaining on the membrane after the milk block, it was found that acid-bound antibodies were unchanged in biological activity when compared with the same antibodies bound at neutral pH. These results suggest that acid binding of proteins could increase the sensitivity of nitrocellulose membrane assays using a milk block.
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Affiliation(s)
- W L Hoffman
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235
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26
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Abstract
Immunoblotting is a commonly used technique for the immunodetection of specific proteins which have been fractionated by polyacrylamide gel electrophoresis. We describe here a simple procedure for the double staining of immunoblots, first to detect the immunoreactive component(s) by histochemistry using enzyme-conjugated secondary antibodies, and second to visualize the general protein electrophoretogram using India ink. This procedure permits the direct comparison of electrophoretic mobilities between the immunoreactive protein(s) and the total protein population as well as protein standards of known Mr. The experimental advantage of the procedure is that no additional manipulation of the protein samples or the standards is necessary prior to electrophoretic fractionation. In this report, detection of the vitamin D-dependent calcium-binding protein, calbindin-D28K, is used to illustrate the application of the procedure.
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Affiliation(s)
- T Ono
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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27
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Abstract
The efficiency of semi-dry electrophoretic transfer after sodium dodecyl sulfate (SDS)-electrophoresis using PhastGel media was investigated in a model system using three isotope labelled proteins. To give a full picture of the blotting process the amount of protein present in the gel, membranes, and filter papers was determined after different transfer times. The influence of the transfer buffer, commonly used additives such as methanol and SDS, and several different immobilizing matrices was investigated. Soybean trypsin inhibitor, bovine serum albumin, and ferritin were used as model proteins to study the effect of size on transfer efficiency. Basically, all three stages of the blotting process decide the result; the elution of protein from the gel, the immobilization of protein to the membrane, and the loss of material from the membrane during transfer. A theoretical explanation for the observed poor binding to a second membrane is discussed. Our results show that the buffer composition has little influence on the efficiency of transfer from the gel, but can be significant to the binding capacity of the membrane. In all experiments performed, there was never one moment during the transfer when all protein was eluted from the gel and simultaneously still bound to the membrane. The highest recovery in the membrane was obtained at different time intervals for different proteins. This indicates that quantitative transfer procedures cannot be generalized. However, obtaining an optimal method for reliable quantification of a specific protein or group of proteins is possible. For general protein staining of nitrocellulose and polyvinylidene difluoride membranes, a highly sensitive silver staining method requiring only 15 min has been used.
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Affiliation(s)
- G Jacobson
- Pharmacia LKB Biotechnology AB, Uppsala, Sweden
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Li KW, Geraerts WP, van Elk R, Joosse J. Quantification of proteins in the subnanogram and nanogram range: comparison of the AuroDye, FerriDye, and India ink staining methods. Anal Biochem 1989; 182:44-7. [PMID: 2481416 DOI: 10.1016/0003-2697(89)90715-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The usefulness of three sensitive dyes, AuroDye, FerriDye, and India ink, for the quantification of proteins and peptides bound to nitrocellulose paper has been assessed. In general, the staining intensity varies linearly with the logarithm of protein concentrations. The detection limit of small peptides (Mr less than 5000) is higher than that of large peptides and proteins, but the sensitivity is independent of the molecular weight. Oligopeptides of four or less amino acids either stain with very high detection limits or do not stain at all. The detection limit of proteins stained by AuroDye is approximately 1 ng, and in a number of cases even lower. The useful range for quantification of proteins extends to around 100 ng. The FerriDye and India ink staining methods are less sensitive and can be used to quantify proteins over a wide nanogram range. Among the methods tested, the India ink staining method has the highest protein to protein variation in sensitivity.
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Affiliation(s)
- K W Li
- Department of Biology, Vrije Universiteit, Amsterdam, The Netherlands
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29
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Abstract
Copper iodide staining which can detect protein levels as low as 100-150 pg/mm2 on nitrocellulose membranes is described. The staining is quantitative as measured by densitometry. Staining is complete within 5 min and may be removed by washing the membrane for 15 min without loss of immunoreactivity. The stain utilizes a reddish-brown precipitate of copper iodide in highly alkaline conditions. Because of its high sensitivity, convenience, and low cost, this stain may be more practical than amido black or gold- and silver-based stains for most laboratory purposes.
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Affiliation(s)
- D D Root
- Molecular Biology Institute, University of California, Los Angeles 90024
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