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Macroscopic evidence, histological sections, transmission electron microscopy (TEM) evaluation, and PCR analyses of 25 apparently diseased juvenile spiny lobsters Panulirus argus from the reef lagoon of Puerto Morelos, Mexico, showed the presence of Panulirus argus Virus 1 (PaV1). Cowdry Type A intranuclear viral inclusions were observed in histological analyses, icosahedral viral particles were observed by TEM, and PCR using specific primers for PaV1 amplified a fragment of 499 bp. This is the first report of PaV1 infecting P. argus outside the Florida Keys, USA. KEY WORDS: Spiny lobster · Panulirus argus · PaV1 · Cowdry Type A intranuclear inclusionsResale or republication not permitted without written consent of the publisher Dis Aquat Org 79: 153-156, 2008 water) and processed by a routine histological method followed by hematoxylin and eosin (H&E) stains (Lightner 1996). Stained sections were observed under a standard light microscope to examine histopathological changes and the images were captured using a digital camera (Evolution™ LC Color). The severity of infection of each tissue type was estimated using the numerical scale of Bell & Lightner (1987), who assigned infection severity grades from 0 to 4 based on the estimated number of diagnostic Cowdry Type A intranuclear inclusions (CAI) per microscopic field(s) at 40 X: Grade 0 = no CAI observed; Grade 1 = 1-5 CAI/200 fields; Grade 2 = 1-2 CAI/20 fields; Grade 3 = 1-5 CAI/2 fields); and Grade 4 >10 CAI/field.For the TEM examinations, the hepatopancreas of 8 lobsters were first fixed in 2.5% glutaraldehyde with 0.2 M sodium cacodylate buffer, then in 1% osmium tetraoxide and further dehydrated in increased serial dilutions of ethanol. Finally, samples were mounted in Spurr's resin. Ultra-thin sectioned samples placed on grids were processed through a routine lead citrate stain and observed with a Jeol microscope (JEM-1200 EX II) (Reynolds 1963).Fifteen lobsters were used for the PCR analysis. Genomic DNA were extracted from ~25 mg of hepatopancreatic tissue using the wizard ® genomic DNA purification kit (Promega ® ) according to the manufacturer's protocol. The primers specific for PaV1 45aF-TCCAGCCCAGGTACGTATC and 543aR-AACAGA-TT-TTCCAGCAGCGT that amplify a region of 499 bp were used after a modification of the original protocol of Montgomery-Fullerton et al. (2007). All PCR reactions were carried out in a total volume of 25 µl containing ~32.5 ng of DNA, 0.33 µM of each primer, 2.5 mM of MgCl 2 , 1.2× reaction buffer (50 mM KCl, 10 mM Tris-HCl, pH 9.0, 0.1% Triton X-100), 0.4 mM dNTPs mixture (Promega ® ), and 2.5 U of Taq DNA polymerase (Promega ® ). Reactions were run on a thermal cycler (TECHNE TC-312) at 94°C for 10 min, followed by 30 cycles of 94°C for 30 s, 63°C for 30 s, and 72°C for 1 min, with a final extension of 72°C for 10 min. PCR products were electrophoresed on 2% agarose gels and bands were visualized using 0.1% ethidium bromide stain on a UV transilluminator. DNA from lobsters collected in the Reef lagoon of Puerto More...

The Caribbean spiny lobster Panulirus argus is a valuable fishing resource and the trade in frozen lobster tails is an important industry. However, the presence of the pathogenic virus Panulirus argus Virus 1 (PaV1), which causes systemic infection in P. argus and is particularly lethal to juvenile individuals, has not been previously examined in imported/exported lobster products. We used PCR assays to determine the presence of PaV1 in abdominal muscle tissue of 22 frozen P. argus tails exported from Belize to Mexico. Based on their size, the tails belonged to subadult -adult lobsters. Using specific primers targeted for PaV1 resulted in 11 tails showing a specific 499 bp band. The sequence of positive amplified fragments showed a high similarity to PaV1 (95% identity with GenBank accession no. EF206313.1). Although the pathogenicity of PaV1 was not evaluated in the present study, our results provide the first evidence of PaV1 in frozen lobster tails exported in the seafood industry as well as the first molecular evidence of PaV1 in adult lobsters. KEY WORDS: Panulirus argus Virus 1 · Frozen lobster tails · Caribbean SeaResale or republication not permitted without written consent of the publisher

The effectiveness of the immune defense of Litopenaeus vannamei previously reared in biofloc or in a traditional clear seawater rearing system was assessed after a bacterial challenge with a pathogenic strain of Vibrio harveyi. The changes caused by its previous rearing system condition or the challenge were assessed in terms of metabolites (glucose, cholesterol, acylglycerides, protein), hemocyanin, the antioxidant defense system (superoxide dismutase, and catalase), and gene expression related to immune response (superoxide dismutase, alpha2 macroglobulin, prophenoloxidase, hemocyanin, and penaeidin‐3a). The biofloc rearing system was associated with a significant increase in protein, the antioxidant defense system, and the superoxide dismutase, alpha2 macroglobulin, and prophenoloxidase genes. For shrimp previously reared in biofloc, a positive interaction with the presence or absence (control) of V. harveyi significantly affected the hemocyanin concentration, and the interaction between the two rearing systems in shrimp challenged with the bacteria produced a higher transcription of the hemocyanin gene. Likewise, biofloc and clear seawater maintained a higher transcription of prophenoloxidase gene after the bacterial challenge. In the absence of the bacteria, shrimp of the biofloc group produced a higher transcription of the penaeidin‐3a gene. V. harveyi caused hepatopancreatic lesions and mortalities only in shrimp previously reared in clear seawater. These results suggest that biofloc helps to prevent the development of disease by improving the shrimp immune response.