K E Y W O R D S : D o m o ic ac id , a m n e s ic she llf ish p o iso n in g (A S P ) , D u n g en ess c ra b , C a n c er m a g is te r , razo r c la m s . S iliq u a p a tu la IN T R O D U C T IO N D o m o i c a c id ( D A ) is t h e n a tu ra l ly o c c u r r i n g n e u r o to x ic a m in o ac id re s p o n s ib le fo r a m n e s i c sh e l l f i s h p o i s o n in g (A S P ) (Q u i l l i a m a n d W r i g h t 1 9 89 , T o d d 19 9 3 ) . T h i s m a r i n e b io to x in c a u s e s g a s ­ t ro in te s t in a l a n d n e u ro lo g ic a l s y m p t o m s in h u m a n s w i th in 2 4 4 8 h o u r s o f c o n s u m p t i o n , a n d s y m p t o m s r a n g e f ro m s im p le n a u se a a n d v o m i t in g to h e a d a c h e , c o n f u s i o n , p e r m a n e n t s h o r t t e rm m e m ­ o ry lo s s , c o m a , a n d e v e n d e a th . S in c e 1 98 7 , s tu d ie s in C a n a d a and e l s e w h e r e h a v e fo u n d th a t d o m o i c ac id c a n o r ig in a te f ro m p h y t o ­ p l a n k to n , s p e c i f ic a l ly the d i a t o m g e n u s P seudon itzsch ia . T o d a te , d o m o ic a c id h a s b e e n fo u n d to b e p r o d u c e d b y at leas t 4 o f th e 21 s p e c ie s o f P seu d o n itzsch ia d i a to m s : P . p u n g en s fo r m a m ultiseries (H a s le ) H a s le . P . a u stra lis F r e n g u e l l i , P . d e lica tiss im a (C lev e ) H e i d e n , a n d P . seria ta ( C le v e ) P e ra g e l lo ( L u n d h o l m e t a l . 1994). T h e f i rs t o u tb r e a k o f d o m o i c a c id p o i s o n in g in th e U n i ted S ta te s o c c u r r e d in S e p t e m b e r o f 1991. W h i le n o h u m a n i l lnesses s im i l a r to th o se r e p o r t e d in the 1987 C a n a d i a n o u tb r e a k o c c u r r e d , the to x in c a u s e d m o re t h a n 100 p e l ic a n s (P elecanus occiden ta lis L in n a e u s ) a n d c o r m o r a n t s (P h a la cro co ra x p en ic illa tu s B ra n d t ) to b e c o m e ill o r d ie . T h e s e a b i r d s h a d b e e n f e e d in g o n a n c h o v ie s (E ng ra u lis m o rd a x G i r a r d ) , w h i c h h a d g r a z e d o n a b lo o m o f P. a u stra lis ( W o r k e t a l . 19 93 ) . S a m p l e s o f th e s e a n c h o v ie s w ere a n a ly z e d in o u r l a b o ra to ry a n d fo u n d to c o n ta in u p to 4 8 5 p g D A /g v i s c e r a (W e k e l l e t a l . 1994a) . S h o r t ly th e r e a f t e r , d o m o i c a c id w a s d i s c o v e r e d th r o u g h o u t the P ac i f ic c o a s ta l s ta te s o f O r e g o n a n d W a s h in g t o n in O c t o b e r o f 1991. A n e x te n s iv e s u rv e y o f c o a s ta l m a r in e l ife w a s p e r fo rm e d . a n d th e to x in w a s fo u n d in a n c h o v ie s , b lu e m u s s e l s (M ytilu s edu lis L . ) , r a z o r c l a m s (S iliqua p a tu la D i x o n ) , a n d D u n g e n e s s c r a b s (C ancer m a g is ter D a n a ) . D u r in g the t o x i n ' s p e a k in W a s h in g t o n , o u r l a b o ra to ry re p o r te d u p to 2 3 0 p g D A / g m e a t t i s su e ( a v e r a g e = 106 p g / g ; N = 3 6 ) in r a z o r c l a m s , a n d u p t o 9 0 p g D A / g raw v is c e ra ( a v e r a g e = 15 p g / g ; N = 8 7 ) in D u n g e n e s s c r a b s . T h e s o u rc e o f d o m o i c a c id in W a s h in g to n a n d O r e g o n w a s n e v e r c o n ­ f i rm e d ; h o w e v e r , P . austra lis , P . p u n g en s ƒ. m u ltiseries , a n d P. p seudodelica tiss im a (H a s le ) H a s le h a v e b e e n id e n t i f ie d in w a te rs o f th e P a c i f ic N o r th w e s t ( H o m e r 1 99 3 , p e r s . c o m m . ) . H u m a n i l ln e sses w e r e a v o i d e d b e c a u s e o f t h e t i m e ly a c t io n o f lo c a l , s ta te , a n d fede ra l a g e n c i e s id e n t i fy in g the th re a t a n d c lo s in g the a f fe c te d f i s h e r ie s un ti l t h e y w e r e c o n s id e r e d s a f e ( i . e . , b e l o w 2 0 p g D A /g ) . D u r in g 1 99 2 . th e lega l l im it f o r c r a b v i s c e r a w a s r a i s e d to 3 0 p g D A /g ( U .S . F D A 19 93 ) . T h e s e c lo s u re s a n d s u b s e q u e n t r e s t r ic ­ t io n s h a v e h a d s ig n i f ic a n t f in an c ia l im p a c t s o n b o th th e f i sh e r ie s a n d th e s u p p o r t in g c o m m u n i t i e s . T h e D u n g e n e s s c r a b in d u s t ry is a n im p o r ta n t c o m p o n e n t o f the e c o n o m i e s o f th e P a c i f ic c o a s ta l s ta te s . In W a s h in g t o n , O r e g o n , a n d C a l i f o r n i a th e re a re o v e r 1 ,2 0 0 c r a b f i s h e r ie s . T h i s ind us t ry lan d s a n a v e r a g e o f $ 3 2 m i l l io n p o u n d s o f c r a b p e r s e a s o n , resu l ts in a n a v e ra g e an n u a l p o s t -p ro c e s s in g v a lu e o f $ 1 1 2 m i l l io n , a n d c o n t r ib u te s s ig n i f ic a n t ly to e m p l o y m e n t in o th e rw is e e c o n o m ic a l ly d e p r e s s e d a r e a s (D id i e r 1995) . It w a s b e c a u s e k n o w l e d g e c o n c e r n i n g d o m o i c ac id p ro d u c t io n a n d m o v e m e n t t h ro u g h the m a r in e fo o d w e b w a s e x t r e m e l y l i m ­ i ted , th a t s ta te a n d federa l r isk m a n a g e r s h a d l i tt le c h o i c e b u t to i m p le m e n t to ta l c lo s u re s o f th e D u n g e n e s s c r a b a n d r a z o r c la m

Abstract Domoic acid (DA) is a potent toxin produced by bloom-forming phytoplankton in the genus Pseudo-nitzschia, which is responsible for causing amnesic shellfish poisoning (ASP) in humans. ASP symptoms include vomiting, diarrhea, and in more severe cases confusion, loss of memory, disorientation, and even coma or death. This paper describes the development and validation of a rapid, sensitive, enzyme linked immunosorbent assay test kit for detecting DA using a monoclonal antibody. The assay gives equivalent results to those obtained using standard high performance liquid chromatography, fluorenylmethoxycarbonyl high performance liquid chromatography, or liquid chromatography—mass spectrometry methods. It has a linear range from 0.1–3 ppb and was used successfully to measure DA in razor clams, mussels, scallops, and phytoplankton. The assay requires approximately 1.5 h to complete and has a standard 96-well format where each strip of eight wells is removable and can be stored at 4°C until needed. The first two wells of each strip serve as an internal control eliminating the need to run a standard curve. This allows as few as 3 or as many as 36 duplicate samples to be run at a time enabling real-time sample processing and limiting degradation of DA, which can occur during storage. There was minimal cross-reactivity in this assay with glutamine, glutamic acid, kainic acid, epi- or iso-DA. This accurate, rapid, cost-effective, assay offers environmental managers and public health officials an effective tool for monitoring DA concentrations in environment samples.

The amnesic shellfish poison domoic acid is produced by marine algae of the genus Pseudo-nitzschia. We have developed a portable surface plasmon resonance (SPR) biosensor system for the detection of domoic acid. Because of concerns with domoic acid contamination of shellfish, there is a need for rapid field quantification of toxin levels in both shellfish and seawater. Antibodies were raised against domoic acid and affinity purified. These antibodies were used to develop competition- and displacement-based assays using a portable six-channel SPR system developed in our laboratories. Standard curves for detection of domoic acid in phosphate buffered saline and in diluted clam extracts analyzed by the competition-based SPR assay demonstrated a limit of detection of 3ppb (10nM) and a quantifiable range from 4 to 60ppb (13–200nM). Comparison of analyses for domoic acid levels in Pacific razor clams, Siliqua patula, containing moderate to high levels of domoic acid by the standard HPLC analysis protocol and the SPR-based assay gave an excellent correlation. This same technology should also function for detection of domoic acid in concentrated algal extracts or high dissolved levels in seawater.

Domoic acid (DA) levels in Washington State razor clams (Siliqua patula) have been extremely variable and unpredictable, resulting in emergency closures of harvest areas in 1991, 1998, and 1999. Information concerning toxin variability relative to sampling location is important in developing a more reliable plan for managing DA outbreaks. In November 1998, record levels of DA in razor clams (up to 295ppm) were reported at Kalaloch beach, Washington. A razor clam resource survey conducted there during the summer of 1999, along with the long retention time of DA in the clams, permitted a study of DA levels as a function of tidal elevation and north-south beach location. During the summer low tides (28–31 July 1999) razor clams were collected from six east-west transects, approximately 1.6km apart. Each clam was individually analyzed for DA to determine the distribution of toxin between (interspecific variability) and within (intraspecific variability) transects. While average DA levels were similar between transects, toxin levels varied substantially among individual clams. The coefficient of variation among all samples (n=445) was 122%, indicating that harvest closures based upon composite analyses of only six clams could be in error. Here we recommend a sampling strategy of razor clams for regulatory purposes that will result in DA measurements more representative of total population toxin values.

Contamination of fish feeds with the toxin, domoic acid, through use of contaminated fish meal is a possibility. To test the stability of domoic acid during fish meal and fish feed manufacturing, fish meal was made from anchovies containing 43 mu g domoic acid/g wet fish using a closed vacuum dryer, resulting in fish meal containing 130 mu g domoic acid/g of meal. This product was used in place of commercial herring meal in a dry, pelleted feed, constituting 50% of the feed formulation. The feed contained 58 mu g domoic acid/g. To determine if dietary domoic acid affected the health of rainbow trout or was retained in the tissue, duplicate groups of trout, average initial weight 25 g, were fed a control diet, made with herring meal, and the domoic acid diet for 15 weeks, during which time the average weight of the trout increased to 48 g. No differences in feed consumption, weight gain, or feed efficiency ratio were observed between groups of fish fed the control or domoic acid feed. No mortality or signs of toxicity or neurological distress were observed in either dietary treatment group. Analysis of fish tissue showed no detectable concentrations of domoic acid in fillets or viscera portions of the fish when the fish were sampled after a 48-h fast. Domoic acid was present in the feces and viscera, but not in blood or muscle of the fish following an overnight fast. These results suggest that domoic acid in fish feed, when present at a concentration likely to be encountered in practical situations, is not readily absorbed by rainbow trout and does not present a health hazard to the fish or to the consumer.

In the analysis of trimethylamine oxide (TMAO) in fish tissues, an equimolar mixture of ferrous sulfate (FeSO4) and disodium ethylenediaminetetraacetic acid (EDTA) (0.1 M) in acetate buffer (0.8 M, pH 4.5) was found to be a satisfactory replacement for titanium chloride (TiCl3). The TiCl3 method for TMAO was usually conducted at 80-degrees-C; the FeSO4-EDTA reaction at 50-degrees-C appeared complete in 5 min and yielded comparable results. The use of an acetate buffer alleviated any interference from the trichloroacetic acid used for extraction of TMAO and trimethylamine (TMA) from fish tissue.

ABSTRACTSignificant reduction of curd in canned salmon prepared from frozen fish was achieved. Prior to being placed in the can, salmon steaks or pieces were given dips of a few seconds to 2 min in sodium poly‐phosphate in concentrations from 5% to saturated. Curd was effectively reduced in canned pink and sockeye salmon prepared from fish in frozen storage for up to a year, to a level at least equivalent to canned salmon prepared from fresh fish. Improvements in flavor and texture were noted. A simple scoring system is presented for evaluating canned salmon based upon visual scoring of curd present on the surface of canned product.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTLC—Versatile toolDonald C. Malins and John C. Wekell Cite this: J. Chem. Educ. 1963, 40, 10, 531Publication Date (Print):October 1, 1963Publication History Received3 August 2009Published online1 October 1963Published inissue 1 October 1963https://doi.org/10.1021/ed040p531RIGHTS & PERMISSIONSArticle Views869Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (3 MB) Get e-Alerts Get e-Alerts