27. Cole, A.R.; Gibert, M.; Popoff, M.; Moss, D.S.; Titball, R.W.; Basak, A.K. *Clostridium perfringens* ε-toxin shows structural similarity to the pore-forming toxin aerolysin. *Nat. Struct. Mol. Biol.* **2004**, *11*, 797–798. [CrossRef]

28. Robertson, S.L.; Smedley, J.G., 3rd; Singh, U.; Chakrabarti, G.; Van Itallie, C.M.; Anderson, J.M.; McClane, B.A. Compositional and stoichiometric analysis of *Clostridium perfringens* enterotoxin complexes in Caco-2 cells and claudin 4 fibroblast transfectants. *Cell. Microbiol.* **2007**, *9*, 2734–2755. [CrossRef]

29. Smedley, J.G., 3rd; Uzal, F.A.; McClane, B.A. Identification of a prepore large-complex stage in the mechanism of action of *Clostridium perfringens* enterotoxin. *Infect. Immun.* **2007**, *75*, 2381–2390. [CrossRef]

30. Chen, J.; Theoret, J.R.; Shrestha, A.; Smedley, J.G., 3rd; McClane, B.A. Cysteine-scanning mutagenesis supports the importance of *Clostridium perfringens* enterotoxin amino acids 80 to 106 for membrane insertion and pore formation. *Infect. Immun.* **2012**, *80*, 4078–4088. [CrossRef]

31. McClane, B.A.; McDonel, J.L. Characterization of membrane permeability alterations induced in Vero cells by *Clostridium perfringens* enterotoxin. *Biochim. Biophys. Acta* **1980**, *600*, 974–985. [CrossRef]

32. Hardy, S.P.; Denmead, M.; Parekh, N.; Granum, P.E. Cationic currents induced by *Clostridium perfringens* type A enterotoxin in human intestinal CaCO-2 cells. *J. Med. Microbiol.* **1999**, *48*, 235–243. [CrossRef]

33. McClane, B.A.; Wnek, A.P.; Hulkower, K.I.; Hanna, P.C. Divalent cation involvement in the action of *Clostridium perfringens* type A enterotoxin. Early events in enterotoxin action are divalent cation-independent. *J. Biol. Chem.* **1988**, *263*, 2423–2435. [CrossRef]

34. Matsuda, M.; Ozutsumi, K.; Iwahashi, H.; Sugimoto, N. Primary action of *Clostridium perfringens* type A enterotoxin on HeLa and Vero cells in the absence of extracellular calcium: Rapid and characteristic changes in membrane permeability. *Biochem. Biophys. Res. Commun.* **1986**, *141*, 704–710. [CrossRef]

35. Krause, G.; Winkler, L.; Mueller, S.L.; Haseloff, R.F.; Piontek, J.; Blasig, I.E. Structure and function of claudins. *Biochim. Biophys. Acta* **2008**, *1778*, 631–645. [CrossRef]

36. Mineta, K.; Yamamoto, Y.; Yamazaki, Y.; Tanaka, H.; Tada, Y.; Saito, K.; Tamura, A.; Igarashi, M.; Endo, T.; Takeuchi, K.; et al. Predicted expansion of the claudin multigene family. *FEBS Lett.* **2011**, *585*, 606–612. [CrossRef]

37. Shinoda, T.; Shinya, N.; Ito, K.; Ohsawa, N.; Terada, T.; Hirata, K.; Kawano, Y.; Yamamoto, M.; Kimura-Someya, T.; Yokoyama, S.; et al. Structural basis for disruption of claudin assembly in tight junctions by an enterotoxin. *Sci. Rep.* **2016**, *6*, 33632. [CrossRef]

38. Veshnyakova, A.; Protze, J.; Rossa, J.; Blasig, I.E.; Krause, G.; Piontek, J. On the interaction of *Clostridium perfringens* enterotoxin with claudins. *Toxins* **2010**, *2*, 1336–1356. [CrossRef]

39. Saitoh, Y.; Suzuki, H.; Tani, K.; Nishikawa, K.; Irie, K.; Ogura, Y.; Tamura, A.; Tsukita, S.; Fujiyoshi, Y. Tight junctions. Structural insight into tight junction disassembly by *Clostridium perfringens* enterotoxin. *Science* **2015**, *347*, 775–778. [CrossRef]

40. Mitchell, L.A.; Koval, M. Specificity of interaction between *Clostridium perfringens* enterotoxin and claudin-family tight junction proteins. *Toxins* **2010**, *2*, 1595–1611. [CrossRef]

41. International Organization for Standardization. *EN ISO 7937 Microbiology of Food and Animal Feeding Stuffs—Horizontal Method for the Enumeration of Clostridium Perfringens—Colony-Count Technique*; International Organization for Standardization: Geneva, Switzerland, 2004.

42. Veloo, A.C.; Knoester, M.; Degener, J.E.; Kuijper, E.J. Comparison of two matrix-assisted laser desorption ionisation-time of flight mass spectrometry methods for the identification of clinically relevant anaerobic bacteria. *Clin. Microbiol. Infect.* **2011**, *17*, 1501–1506. [CrossRef]

43. Coltella, L.; Mancinelli, L.; Onori, M.; Lucignano, B.; Menichella, D.; Sorge, R.; Raponi, M.; Mancini, R.; Russo, C. Advancement in the routine identification of anaerobic bacteria by MALDI-TOF mass spectrometry. *Eur. J. Clin. Microbiol. Infect. Dis.* **2013**, *32*, 1183–1192. [CrossRef]

44. Meer, R.R.; Songer, J.G. Multiplex polymerase chain reaction assay for genotyping *Clostridium perfringens*. *Am. J. Vet. Res.* **1997**, *58*, 702–705.

45. Miyamoto, K.; Wen, Q.; McClane, B.A. Multiplex PCR genotyping assay that distinguishes between isolates of *Clostridium perfringens* type A carrying a chromosomal enterotoxin gene (*cpe*) locus, a plasmid *cpe* locus with an IS1470-like sequence, or a plasmid *cpe* locus with an IS1151 sequence. *J. Clin. Microbiol.* **2004**, *42*, 1552–1558. [CrossRef]

46. Wen, Q.; Miyamoto, K.; McClane, B.A. Development of a duplex PCR genotyping assay for distinguishing *Clostridium perfringens* type A isolates carrying chromosomal enterotoxin (*cpe*) genes from those carrying plasmid-borne enterotoxin (*cpe*) genes. *J. Clin. Microbiol.* **2003**, *41*, 1494–1498. [CrossRef]

47. Duncan, C.L. Time of enterotoxin formation and release during sporulation of *Clostridium perfringens* type A. *J. Bacteriol.* **1973**, *113*, 932–936. [CrossRef]

48. McClane, B.A.; Snyder, J.T. Development and preliminary evaluation of a slide latex agglutination assay for detection of *Clostridium perfringens* type A enterotoxin. *J. Immunol. Methods* **1987**, *100*, 131–136. [CrossRef]

49. McClane, B.A.; Strouse, R.J. Rapid detection of *Clostridium perfringens* type A enterotoxin by enzyme-linked immunosorbent assay. *J. Clin. Microbiol.* **1984**, *19*, 112–115. [CrossRef]

50. Uemura, T.; Yoshitake, S.; Hu, D.; Kajikawa, T. A highly sensitive enzyme-linked immunosorbent assay for *Clostridium perfringens* enterotoxin. *Lett. Appl. Microbiol.* **1992**, *15*, 23–25. [CrossRef]

51. Mehta, R.; Narayan, K.G.; Notermans, S. DOT-enzyme linked immunosorbent assay for detection of *Clostridium perfringens* type A enterotoxin. *Int. J. Food Microbiol.* **1989**, *9*, 45–50. [CrossRef]
52. Pöhlmann, C.; Elßner, T. Multiplex immunoassay techniques for on-site detection of security sensitive toxins. *Toxins* **2020**, *12*, 727. [CrossRef] [PubMed]

53. Smedley, J.G., 3rd; McClane, B.A. Fine mapping of the N-terminal cytotoxicity region of *Clostridium perfringens* enterotoxin by site-directed mutagenesis. *Infect. Immun.* **2004**, *72*, 6914–6923. [CrossRef] [PubMed]

54. Shinoda, T.; Shinya, N.; Ito, K.; Ishizuka-Katsura, Y.; Ohsawa, N.; Terada, T.; Hirata, K.; Kawano, Y.; Yamamoto, M.; Tomita, T.; et al. Cell-free methods to produce structurally intact mammalian membrane proteins. *Sci. Rep.* **2016**, *6*, 30442. [CrossRef] [PubMed]

55. Weisemann, J.; Mahrhold, S.; Krüger, M.; Neumann, T.; Krez, N.; Dorner, B.G.; Rummel, A. Functionalization of the protein receptor claudin-4 for detection of Clostridium perfringens enterotoxin. Manuscript in preparation. *Clostridium erfringens* enterotoxin. Manuscript in preparation.

56. Elsholz, B.; Wörl, R.; Blohm, L.; Albers, J.; Feucht, H.; Grunwald, T.; Jürgen, B.; Schweder, T.; Hintsche, R. Automated detection and quantitation of bacterial RNA by using electrical microarrays. *Anal. Chem.* **2006**, *78*, 4794–4802. [CrossRef]

57. Pauly, D.; Kirchner, S.; Stoermann, B.; Schreiber, T.; Kaulfuss, S.; Schade, R.; Zbinden, R.; Avondet, M.A.; Dorner, M.B.; Dorner, B.G. Simultaneous quantification of five bacterial and plant toxins from complex matrices using a multiplexed fluorescent magnetic suspension assay. *Analyst* **2009**, *134*, 2028–2039. [CrossRef]

58. Stern, D.; Weisemann, J.; Le Blanc, A.; von Berg, L.; Mahrhold, S.; Piesker, J.; Laue, M.; Luppa, P.B.; Dorner, M.B.; Dorner, B.G.; et al. A lipid-binding loop of botulinum neurotoxin serotypes B, DC and G is an essential feature to confer their exquisite potency. *PLoS Pathog.* **2018**, *14*, e1007048. [CrossRef]

59. Da Silva Felício, M.T.; Hald, T.; Liebana, E.; Allende, A.; Hugas, M.; Nguyen-The, C.; Johannessen, G.S.; Niskanen, T.; Uyttendaele, M.; McLauchlin, J. Risk ranking of pathogens in ready-to-eat unprocessed foods of non-animal origin (FoNAO) in the EU: Initial evaluation using outbreak data (2007–2011). *Int. J. Food Microbiol.* **2015**, *195*, 9–19. [CrossRef]

60. Bos, J.; Smithee, L.; McClane, B.; Distefano, R.F.; Uzal, F.; Songer, J.G.; Mallonee, S.; Crutcher, J.M. Fatal necrotizing colitis following a foodborne outbreak of enterotoxigenic *Clostridium perfringens* type A infection. *Clin. Infect. Dis.* **2005**, *40*, e78–e83. [CrossRef]

61. Fujita, K.; Katahira, J.; Horiguchi, Y.; Sonoda, N.; Furuse, M.; Tsukita, S. *Clostridium perfringens* enterotoxin binds to the second extracellular loop of claudin-3, a tight junction integral membrane protein. *FEBS Lett.* **2000**, *476*, 258–261. [CrossRef]

62. Ling, J.; Liao, H.; Clark, R.; Wong, M.S.; Lo, D.D. Structural constraints for the binding of short peptides to claudin-4 revealed by surface plasmon resonance. *J. Biol. Chem.* **2008**, *283*, 30585–30595. [CrossRef]

63. Sonoda, N.; Furuse, M.; Sasaki, H.; Yonemura, S.; Katahira, J.; Horiguchi, Y.; Tsukita, S. *Clostridium perfringens* enterotoxin fragment removes specific claudins from tight junction strands: Evidence for direct involvement of claudins in tight junction barrier. *J. Cell Biol.* **1999**, *147*, 195–204. [CrossRef]

64. Harada, M.; Kondoh, M.; Ebihara, C.; Takahashi, A.; Komiya, E.; Fujii, M.; Mizuguchi, H.; Tsunoda, S.; Horiguchi, Y.; Yagi, K.; et al. Role of tyrosine residues in modulation of claudin-4 by the C-terminal fragment of *Clostridium perfringens* enterotoxin. *Biochem. Pharmacol.* **2007**, *73*, 206–214. [CrossRef]

65. Forti, K.; Ferroni, L.; Pellegrini, M.; Cruciani, D.; De Giuseppe, A.; Crotti, S.; Papa, P.; Maresca, C.; Severi, G.; Marenzoni, M.L.; et al. Molecular characterization of *Clostridium perfringens* strains isolated in Italy. *Toxins* **2020**, *12*, 650. [CrossRef]

66. Mahamat Abdelrahim, A.; Radomski, N.; Delannoy, S.; Djellal, S.; Le Négrate, M.; Hadjab, K.; Fach, P.; Hennekinne, J.A.; Mistou, M.Y.; Firmesse, O. Large-scale genomic analyses and toxinotyping of *Clostridium perfringens* implicated in foodborne outbreaks in France. *Front. Microbiol.* **2019**, *10*, 777. [CrossRef]

67. Legros, N.; Pohlentz, G.; Steil, D.; Müthing, J. Shiga toxin-glycosphingolipid interaction: Status quo of research with focus on primary human brain and kidney endothelial cells. *Int. J. Med. Microbiol.* **2018**, *308*, 1073–1084. [CrossRef]

68. Bartholomew, B.A.; Stringer, M.F.; Watson, G.N.; Gilbert, R.J. Development and application of an enzyme linked immunosorbent assay for *Clostridium perfringens* type A enterotoxin. *J. Clin. Pathol.* **1985**, *38*, 222–228. [CrossRef]

69. Das, S.; Majumder, S.; Nag, M.; Kingston, J.J. A sandwich duplex immuno PCR for rapid and sensitive identification of *Clostridium perfringens* alpha and enterotoxin. *Anaerobe* **2019**, *57*, 63–74. [CrossRef]

70. RIDASCREEN®. Clostridium Perfringens Enterotoxin ELISA. Available online: https://clinical.r-biopharm.com/products/ridascreen-clostridium-perfringens-enterotoxin/ (accessed on 19 February 2021).

71. Wimsatt, J.C.; Harmon, S.M.; Shah, D.B. Detection of *Clostridium perfringens* enterotoxin in stool specimens and culture supernatants by enzyme-linked immunosorbent assay. *Diagn. Microbiol. Infect. Dis.* **1986**, *4*, 307–313. [CrossRef]

72. Berry, P.R.; Rodhouse, J.C.; Hughes, S.; Bartholomew, B.A.; Gilbert, R.J. Evaluation of ELISA, RPLA, and Vero cell assays for detecting *Clostridium perfringens* enterotoxin in faecal specimens. *J. Clin. Pathol.* **1988**, *41*, 458–461. [CrossRef]

73. Minamoto, Y.; Dhanani, N.; Markel, M.E.; Steiner, J.M.; Suchodolski, J.S. Prevalence of Clostridium perfringens, Clostridium perfringens enterotoxin and dysbiosis in fecal samples of dogs with diarrhea. *Vet. Microbiol.* **2014**, *174*, 463–473. [CrossRef]

74. Kyne, L.; Warny, M.; Qamar, A.; Kelly, C.P. Association between antibody response to toxin A and protection against recurrent *Clostridium difficile* diarrhoea. *Lancet* **2001**, *357*, 189–193. [CrossRef]

75. Skjelkvål, R.; Duncan, C.L. Characterization of enterotoxin purified from *Clostridium perfringens* type C. *Infect. Immun.* **1975**, *11*, 1061–1068. [CrossRef]

76. Dorner, B.G.; Steinbach, S.; Hüser, M.B.; Kroczek, R.A.; Scheffold, A. Single-cell analysis of the murine chemokines MIP-1a, MIP-1b, RANTES and ATAC/lymphotactin by flow cytometry. *J. Immunol. Methods* **2003**, *274*, 83–91. [CrossRef]
52. Pöhlmann, C.; Elßner, T. Multiplex immunoassay techniques for on-site detection of security sensitive toxins. *Toxins* **2020**, *12*, 727. [CrossRef] [PubMed]

53. Smedley, J.G., 3rd; McClane, B.A. Fine mapping of the N-terminal cytotoxicity region of *Clostridium perfringens* enterotoxin by site-directed mutagenesis. *Infect. Immun.* **2004**, *72*, 6914–6923. [CrossRef] [PubMed]

54. Shinoda, T.; Shinya, N.; Ito, K.; Ishizuka-Katsura, Y.; Ohsawa, N.; Terada, T.; Hirata, K.; Kawano, Y.; Yamamoto, M.; Tomita, T.; et al. Cell-free methods to produce structurally intact mammalian membrane proteins. *Sci. Rep.* **2016**, *6*, 30442. [CrossRef] [PubMed]

55. Weisemann, J.; Mahrhold, S.; Krüger, M.; Neumann, T.; Krez, N.; Dorner, B.G.; Rummel, A. Functionalization of the protein receptor claudin-4 for detection of Clostridium perfringens enterotoxin. Manuscript in preparation. *Clostridium erfringens* enterotoxin. Manuscript in preparation.

56. Elsholz, B.; Wörl, R.; Blohm, L.; Albers, J.; Feucht, H.; Grunwald, T.; Jürgen, B.; Schweder, T.; Hintsche, R. Automated detection and quantitation of bacterial RNA by using electrical microarrays. *Anal. Chem.* **2006**, *78*, 4794–4802. [CrossRef]

57. Pauly, D.; Kirchner, S.; Stoermann, B.; Schreiber, T.; Kaulfuss, S.; Schade, R.; Zbinden, R.; Avondet, M.A.; Dorner, M.B.; Dorner, B.G. Simultaneous quantification of five bacterial and plant toxins from complex matrices using a multiplexed fluorescent magnetic suspension assay. *Analyst* **2009**, *134*, 2028–2039. [CrossRef]

58. Stern, D.; Weisemann, J.; Le Blanc, A.; von Berg, L.; Mahrhold, S.; Piesker, J.; Laue, M.; Luppa, P.B.; Dorner, M.B.; Dorner, B.G.; et al. A lipid-binding loop of botulinum neurotoxin serotypes B, DC and G is an essential feature to confer their exquisite potency. *PLoS Pathog.* **2018**, *14*, e1007048. [CrossRef]

59. Da Silva Felício, M.T.; Hald, T.; Liebana, E.; Allende, A.; Hugas, M.; Nguyen-The, C.; Johannessen, G.S.; Niskanen, T.; Uyttendaele, M.; McLauchlin, J. Risk ranking of pathogens in ready-to-eat unprocessed foods of non-animal origin (FoNAO) in the EU: Initial evaluation using outbreak data (2007–2011). *Int. J. Food Microbiol.* **2015**, *195*, 9–19. [CrossRef]

60. Bos, J.; Smithee, L.; McClane, B.; Distefano, R.F.; Uzal, F.; Songer, J.G.; Mallonee, S.; Crutcher, J.M. Fatal necrotizing colitis following a foodborne outbreak of enterotoxigenic *Clostridium perfringens* type A infection. *Clin. Infect. Dis.* **2005**, *40*, e78–e83. [CrossRef]

61. Fujita, K.; Katahira, J.; Horiguchi, Y.; Sonoda, N.; Furuse, M.; Tsukita, S. *Clostridium perfringens* enterotoxin binds to the second extracellular loop of claudin-3, a tight junction integral membrane protein. *FEBS Lett.* **2000**, *476*, 258–261. [CrossRef]

62. Ling, J.; Liao, H.; Clark, R.; Wong, M.S.; Lo, D.D. Structural constraints for the binding of short peptides to claudin-4 revealed by surface plasmon resonance. *J. Biol. Chem.* **2008**, *283*, 30585–30595. [CrossRef]

63. Sonoda, N.; Furuse, M.; Sasaki, H.; Yonemura, S.; Katahira, J.; Horiguchi, Y.; Tsukita, S. *Clostridium perfringens* enterotoxin fragment removes specific claudins from tight junction strands: Evidence for direct involvement of claudins in tight junction barrier. *J. Cell Biol.* **1999**, *147*, 195–204. [CrossRef]

64. Harada, M.; Kondoh, M.; Ebihara, C.; Takahashi, A.; Komiya, E.; Fujii, M.; Mizuguchi, H.; Tsunoda, S.; Horiguchi, Y.; Yagi, K.; et al. Role of tyrosine residues in modulation of claudin-4 by the C-terminal fragment of *Clostridium perfringens* enterotoxin. *Biochem. Pharmacol.* **2007**, *73*, 206–214. [CrossRef]

65. Forti, K.; Ferroni, L.; Pellegrini, M.; Cruciani, D.; De Giuseppe, A.; Crotti, S.; Papa, P.; Maresca, C.; Severi, G.; Marenzoni, M.L.; et al. Molecular characterization of *Clostridium perfringens* strains isolated in Italy. *Toxins* **2020**, *12*, 650. [CrossRef]

66. Mahamat Abdelrahim, A.; Radomski, N.; Delannoy, S.; Djellal, S.; Le Négrate, M.; Hadjab, K.; Fach, P.; Hennekinne, J.A.; Mistou, M.Y.; Firmesse, O. Large-scale genomic analyses and toxinotyping of *Clostridium perfringens* implicated in foodborne outbreaks in France. *Front. Microbiol.* **2019**, *10*, 777. [CrossRef]

67. Legros, N.; Pohlentz, G.; Steil, D.; Müthing, J. Shiga toxin-glycosphingolipid interaction: Status quo of research with focus on primary human brain and kidney endothelial cells. *Int. J. Med. Microbiol.* **2018**, *308*, 1073–1084. [CrossRef]

68. Bartholomew, B.A.; Stringer, M.F.; Watson, G.N.; Gilbert, R.J. Development and application of an enzyme linked immunosorbent assay for *Clostridium perfringens* type A enterotoxin. *J. Clin. Pathol.* **1985**, *38*, 222–228. [CrossRef]

69. Das, S.; Majumder, S.; Nag, M.; Kingston, J.J. A sandwich duplex immuno PCR for rapid and sensitive identification of *Clostridium perfringens* alpha and enterotoxin. *Anaerobe* **2019**, *57*, 63–74. [CrossRef]

70. RIDASCREEN®. Clostridium Perfringens Enterotoxin ELISA. Available online: https://clinical.r-biopharm.com/products/ridascreen-clostridium-perfringens-enterotoxin/ (accessed on 19 February 2021).

71. Wimsatt, J.C.; Harmon, S.M.; Shah, D.B. Detection of *Clostridium perfringens* enterotoxin in stool specimens and culture supernatants by enzyme-linked immunosorbent assay. *Diagn. Microbiol. Infect. Dis.* **1986**, *4*, 307–313. [CrossRef]

72. Berry, P.R.; Rodhouse, J.C.; Hughes, S.; Bartholomew, B.A.; Gilbert, R.J. Evaluation of ELISA, RPLA, and Vero cell assays for detecting *Clostridium perfringens* enterotoxin in faecal specimens. *J. Clin. Pathol.* **1988**, *41*, 458–461. [CrossRef]

73. Minamoto, Y.; Dhanani, N.; Markel, M.E.; Steiner, J.M.; Suchodolski, J.S. Prevalence of Clostridium perfringens, Clostridium perfringens enterotoxin and dysbiosis in fecal samples of dogs with diarrhea. *Vet. Microbiol.* **2014**, *174*, 463–473. [CrossRef]

74. Kyne, L.; Warny, M.; Qamar, A.; Kelly, C.P. Association between antibody response to toxin A and protection against recurrent *Clostridium difficile* diarrhoea. *Lancet* **2001**, *357*, 189–193. [CrossRef]

75. Skjelkvål, R.; Duncan, C.L. Characterization of enterotoxin purified from *Clostridium perfringens* type C. *Infect. Immun.* **1975**, *11*, 1061–1068. [CrossRef]

76. Dorner, B.G.; Steinbach, S.; Hüser, M.B.; Kroczek, R.A.; Scheffold, A. Single-cell analysis of the murine chemokines MIP-1a, MIP-1b, RANTES and ATAC/lymphotactin by flow cytometry. *J. Immunol. Methods* **2003**, *274*, 83–91. [CrossRef]
77. Worbs, S.; Skiba, M.; Söderström, M.; Rapinoja, M.-L.; Zeleny, R.; Russmann, H.; Schimmel, H.; Vanninen, P.; Fredriksson, S.-Å.; Dorner, B.G. Characterization of ricin and *R. communis* agglutinin reference materials. *Toxins* **2015**, *7*, 4906–4934. [CrossRef]

78. Stern, D.; Pauly, D.; Zydek, M.; Müller, C.; Avondet, M.A.; Worbs, S.; Lisdat, F.; Dorner, M.B.; Dorner, B.G. Simultaneous differentiation and quantification of ricin and agglutinin by an antibody-sandwich surface plasmon resonance sensor. *Biosens. Bioelectron.* **2016**, *78*, 111–117. [CrossRef]

79. Myszka, D.G. Improving biosensor analysis. *J. Mol. Recognit.* **1999**, *12*, 279–284. [CrossRef]

80. Laemmli, U.K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. *Nature* **1970**, *227*, 680–685.
[CrossRef]

81. Pauly, D.; Worbs, S.; Kirchner, S.; Shatohina, O.; Dorner, M.B.; Dorner, B.G. Real-time cytotoxicity assay for rapid and sensitive detection of ricin from complex matrices. *PLoS ONE* **2012**, *7*, e35360. [CrossRef]

82. Schulz, K.; Pöhlmann, C.; Dietrich, R.; Märtlbauer, E.; Elßner, T. Electrochemical Biochip Assays Based on Anti-idiotypic Antibodies for Rapid and Automated On-Site Detection of Low Molecular Weight Toxins. *Front. Chem.* **2019**, *7*, 31. [CrossRef]

83. Keyburn, A.L.; Boyce, J.D.; Vaz, P.; Bannam, T.L.; Ford, M.E.; Parker, D.; Di Rubbo, A.; Rood, J.I.; Moore, R.J. NetB, a new toxin that is associated with avian necrotic enteritis caused by Clostridium perfringens. *PLoS Pathog.* **2008**, *4*, e26. [CrossRef] [PubMed]

84. Messelhäußer, U.; Ziegler, H.; Elmer-Englhard, D.; Busch, U.; Hörmansdorfer, S.; Kahlau, D.; Pudich, U.; Höller, C. Development of real-time PCR assays for detection and characterization of *Clostridium perfringens* in food samples. *Arch. Lebensm.* **2006**, *57*, 102–105. [CrossRef]
77. Worbs, S.; Skiba, M.; Söderström, M.; Rapinoja, M.-L.; Zeleny, R.; Russmann, H.; Schimmel, H.; Vanninen, P.; Fredriksson, S.-Å.; Dorner, B.G. Characterization of ricin and *R. communis* agglutinin reference materials. *Toxins* **2015**, *7*, 4906–4934. [CrossRef]

78. Stern, D.; Pauly, D.; Zydek, M.; Müller, C.; Avondet, M.A.; Worbs, S.; Lisdat, F.; Dorner, M.B.; Dorner, B.G. Simultaneous differentiation and quantification of ricin and agglutinin by an antibody-sandwich surface plasmon resonance sensor. *Biosens. Bioelectron.* **2016**, *78*, 111–117. [CrossRef]

79. Myszka, D.G. Improving biosensor analysis. *J. Mol. Recognit.* **1999**, *12*, 279–284. [CrossRef]

80. Laemmli, U.K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. *Nature* **1970**, *227*, 680–685.
[CrossRef]

81. Pauly, D.; Worbs, S.; Kirchner, S.; Shatohina, O.; Dorner, M.B.; Dorner, B.G. Real-time cytotoxicity assay for rapid and sensitive detection of ricin from complex matrices. *PLoS ONE* **2012**, *7*, e35360. [CrossRef]

82. Schulz, K.; Pöhlmann, C.; Dietrich, R.; Märtlbauer, E.; Elßner, T. Electrochemical Biochip Assays Based on Anti-idiotypic Antibodies for Rapid and Automated On-Site Detection of Low Molecular Weight Toxins. *Front. Chem.* **2019**, *7*, 31. [CrossRef]

83. Keyburn, A.L.; Boyce, J.D.; Vaz, P.; Bannam, T.L.; Ford, M.E.; Parker, D.; Di Rubbo, A.; Rood, J.I.; Moore, R.J. NetB, a new toxin that is associated with avian necrotic enteritis caused by Clostridium perfringens. *PLoS Pathog.* **2008**, *4*, e26. [CrossRef] [PubMed]

84. Messelhäußer, U.; Ziegler, H.; Elmer-Englhard, D.; Busch, U.; Hörmansdorfer, S.; Kahlau, D.; Pudich, U.; Höller, C. Development of real-time PCR assays for detection and characterization of *Clostridium perfringens* in food samples. *Arch. Lebensm.* **2006**, *57*, 102–105. [CrossRef]