Polyclonal anti-idiotypes induce specific anti-saxitoxin antibody responses

A Comprehensive Review: Development of Electrochemical Biosensors for Detection of Cyanotoxins in Freshwater

Cyanobacteria harmful algal blooms are increasing in frequency and cyanotoxins have become an environmental and public concern in the U.S. and worldwide. In this Review, the majority of reported studies and developments of electrochemical affinity biosensors for cyanotoxins are critically reviewed and discussed. Essential background information about cyanobacterial toxins and electrochemical biosensors is combined with the rapidly moving development of electrochemical biosensors for these toxins. Current issues and future challenges for the development of useful electrochemical biosensors for cyanotoxin detection that meet the demands for applications in field freshwater samples are discussed. The major aspects of the entire review article in a prescribed sequence include (i) the state-of-the-art knowledge of the toxicity of cyanotoxins, (ii) important harmful algal bloom events, (iii) advisories, guidelines, and regulations, (iv) conventional analytical methods for determination of cyanotoxins, (v) electrochemical transduction, (vi) recognition receptors, (vii) reported electrochemical biosensors for cyanotoxins, (viii) summary of analytical performance, and (ix) recent advances and future trends. Discussion includes electrochemical techniques and devices, biomolecules with high affinity, numerous array designs, various detection approaches, and research strategies in tailoring the properties of the transducer-biomolecule interface. Scientific and engineering aspects are presented in depth. This review aims to serve as a valuable source to scientists and engineers entering the interdisciplinary field of electrochemical biosensors for detection of cyanotoxins in freshwaters.

Yeast killer systems

The killer phenomenon in yeasts has been revealed to be a multicentric model for molecular biologists, virologists, phytopathologists, epidemiologists, industrial and medical microbiologists, mycologists, and pharmacologists. The surprisingly widespread occurrence of the killer phenomenon among taxonomically unrelated microorganisms, including prokaryotic and eukaryotic pathogens, has engendered a new interest in its biological significance as well as its theoretical and practical applications. The search for therapeutic opportunities by using yeast killer systems has conceptually opened new avenues for the prevention and control of life-threatening fungal diseases through the idiotypic network that is apparently exploited by the immune system in the course of natural infections. In this review, the biology, ecology, epidemiology, therapeutics, serology, and idiotypy of yeast killer systems are discussed.

Immobilization of small molecules on solid matrices: a novel approach to enzyme-linked immunosorbent assay screening for saxitoxin and evaluation of anti-saxitoxin antibodies

A novel enzyme-linked immunosorbent assay (ELISA) technology was developed for detecting saxitoxin or evaluation of anti-saxitoxin antibodies, which is based on non-covalent immobilization "free' saxitoxin to Maxisorp microtitre plates. The effect of pH on immobilization was studied in media with wide-range buffering capacities (piperazine-glycylglycine and barbiturate buffers). Increasing pH resulted in better responses, although this was mainly due to non-specific interactions. At pH 10.0, however, saxitoxin immobilization was quite effective and specific. The same pattern was found under four different conditions; absence vs presence of bovine serum albumin precoating and absence vs presence of 150 mM NaCl. The best results (high specific response) were achieved with bovine serum albumin precoating in the presence of 150 mM NaCl. The method of choice involved precoating Maxisorp with 5 micrograms/ml albumin followed by addition of 5 microM saxitoxin in 0.01 M piperazine-glycylglycine buffer, pH 10.0. The efficacy of this technology was demonstrated on a polyclonal rabbit anti-saxitoxin antibody and compared with a conventional ELISA of saxitoxin using saxitoxin-bovine serum albumin conjugate as the coating antigen. In the experiments investigating cross-reactivities of various saxitoxin derivatives based on a competitive assay, significantly greater sensitivity was achieved with the novel approach, e.g. 35 pM saxitoxin could be detected (3 x 10(4) times lower concentrations than using the conjugate). The assay works well with mussel tissue homogenates, and because it does not require the use of the covalent saxitoxin-carrier conjugates it offers a simpler alternative to the traditional ELISA for saxitoxin.