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 present study compares 13 physiological and immunological variables between a group of healthy Panulirus argus lobsters and a group of lobsters naturally infected with Panulirus argus Virus 1 (PaV1). Viral infection was determined through histopathology and PCR. Ten of the 13 variables differed significantly between the 2 groups. Using these variables, a principal component analysis yielded 2 separate clusters: one corresponding to the healthy group and the other corresponding to the infected group. In particular, infected lobsters exhibited significantly lower levels of osmotic pressure, total hemocyte counts, plasmatic proteins, and total phenoloxidase (PO) activity in plasma, as well as significantly higher levels of cholesterol and acylglycerides. These features are consistent with metabolic wasting, hyperlipidemia, and presumed immune suppression. Infection with PaV1 appears to increase the susceptibility of lobsters to some other opportunistic pathogens, as 61.1% of infected lobsters presented infestations of ciliate epibionts (Epystilis and Zoothamniun) in the gill chamber compared with 11.5% lobsters in the healthy group. Infected lobsters also showed significantly higher levels of total PO activity in degranulated hemocytes and trypsin inhibitor activity, potentially indicating activation of immune response by the PO system during the systemic infection with PaV1.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.