White feces syndrome of shrimp arises from transformation, sloughing and aggregation of hepatopancreatic microvilli into vermiform bodies superficially resembling gregarines.

Accompanying acute hepatopancreatic necrosis disease (AHPND) in cultivated Asian shrimp has been an increasing prevalence of vermiform, gregarine-like bodies within the shrimp hepatopancreas (HP) and midgut. In high quantity they result in white fecal strings and a phenomenon called white feces syndrome (WFS). Light microscopy (LM) of squash mounts and stained smears from fresh HP tissue revealed that the vermiform bodies are almost transparent with widths and diameters proportional to the HP tubule lumens in which they occur.

N-Linked glycosylation is essential for the yellow head virus replication cycle.

Yellow head virus (YHV) particles contain a nucleocapsid protein (p20) and two envelope glycoproteins (gp116 and gp64). The glycans attached to the two glycoproteins are N-linked and are complex and high mannose types, respectively. Here, we show that treatment with the N-linked glycosylation inhibitor tunicamycin in YHV-infected black tiger shrimp (Penaeus monodon) resulted in less severe yellow head disease and reduced mortality when compared with untreated control shrimp.

Visual detection of white spot syndrome virus using DNA-functionalized gold nanoparticles as probes combined with loop-mediated isothermal amplification.

The integration of loop-mediated isothermal amplification (LAMP) and DNA-functionalized AuNPs as visual detection probes (LAMP-AuNPs) was developed and applied for the detection of white spot syndrome virus (WSSV) from Penaeid shrimp in this study. The principle of this combination assay relies on the basis of stability characteristics of the DNA-functionalized AuNPs upon hybridization with the complementary target DNA toward salt-induced aggregation. If the detected target DNA is not complementary to the ssDNA probes, the DNA-functionalized AuNPs will be aggregated due to the screening effect of salt, resulting in the change of solution color from red to blue/gray and shift of the surface plasmon peak to longer wavelength.

Changes in oviduct structure in the black tiger shrimp, Penaeus monodon, during ovarian maturation.

Objective: To examine the structure of the oviduct of the shrimp Penaeus monodon.

Methods: The oviducts of P. monodon with three different major groups of ovarian development (Group (Gr.

Complete genome sequence of virulence-enhancing Siphophage VHS1 from Vibrio harveyi.

Vibrio harveyi siphophage 1 (VHS1) is a tailed phage with an icosahedral head of approximately 66 nm in diameter and an unornamented, flexible tail of approximately 153 nm in length. When Vibrio harveyi 1114GL is lysogenized with VHS1, its virulence for the black tiger shrimp (Penaeus monodon) increases by more than 100 times, and this coincides with production of a toxin(s) associated with shrimp hemocyte agglutination. Curiously, the lysogen does not show increased virulence for the whiteleg shrimp (Penaeus [Litopenaeus] vannamei).

A novel integrase-containing element may interact with Laem-Singh virus (LSNV) to cause slow growth in giant tiger shrimp.

Background: From 2001-2003 monodon slow growth syndrome (MSGS) caused severe economic losses for Thai shrimp farmers who cultivated the native, giant tiger shrimp, and this led them to adopt exotic stocks of the domesticated whiteleg shrimp as the species of cultivation choice, despite the higher value of giant tiger shrimp. In 2008, newly discovered Laem-Singh virus (LSNV) was proposed as a necessary but insufficient cause of MSGS, and this stimulated the search for the additional component cause(s) of MSGS in the hope that discovery would lead to preventative measures that could revive cultivation of the higher value native shrimp species.

Results: Using a universal shotgun cloning protocol, a novel RNA, integrase-containing element (ICE) was found in giant tiger shrimp from MSGS ponds (GenBank accession number FJ498866).

Monodon baculovirus (MBV) infects the freshwater prawn Macrobrachium rosenbergii cultivated in Thailand.

Field specimens of post-larvae of the giant freshwater prawn (Macrobrachium rosenbergii) from Thailand showed hepatopancreatic tubule epithelial cells that contained central, eosinophilic inclusions within enlarged nuclei and marginated chromatin. These inclusions resembled those produced by some baculoviruses prior to formation of occlusion bodies that enclose virions in a polyhedrin protein matrix. By electron microscopy, the intranuclear inclusions contained bacilliform, enveloped virions (approximately 327+/-29nmx87+/-12nm) with evenly dense, linear nucleocapsids surrounded by trilaminar envelopes with lateral pockets containing nucleoproteinic filaments.

Parvo-like virus in the hepatopancreas of freshwater prawns Macrobrachium rosenbergii cultivated in Thailand.

A survey of cultivated giant freshwater prawns Macrobrachium rosenbergii from Thailand revealed the presence of unusual spherical to ovoid inclusions in nuclei of hepatopancreas tubule epithelial cells. These began as small eosinophilic inclusions that became more basophilic as they increased in size. They were present in both R-cells and E-cells but were largest and deeply basophilic only in the E-cells.

Enterocytozoon hepatopenaei sp. nov. (Microsporida: Enterocytozoonidae), a parasite of the black tiger shrimp Penaeus monodon (Decapoda: Penaeidae): Fine structure and phylogenetic relationships.

A new microsporidian species, Enterocytozoon hepatopenaei sp. nov., is described from the hepatopancreas of the black tiger shrimp Penaeus monodon (Crustacea: Decapoda).

Non-virulence of a recombinant shrimp nidovirus is associated with its non structural gene sequence and not a large structural gene deletion.

RT-PCR using a commercial kit for yellow head virus (YHV) detection in growth-retarded shrimp yielded an unusual 777 bp amplicon instead of expected amplicons of 277 bp for YHV type-1 (YHV-1) or 406 bp for YHV type-2 (YHV-2). Cloning and sequencing (GenBank EU170438) revealed approximately 80% identity to non-structural (NS) ORF1b sequences of both YHV-1 (GenBank AA083987) and YHV-2 (GenBank AF227196), indicating an atypical YHV type (A-YHV) phylogenetically equidistant from both types. An RT-PCR test specifically designed for A-YHV revealed that it was uncommon and that its occurrence in shrimp culture ponds did not correlate with growth retardation or mortality.

The cycle for a Siphoviridae-like phage (VHS1) of Vibrio harveyi is dependent on the physiological state of the host.

In a previous report, we isolated Vibrio harveyi (VH) 1114 together with its bacteriophage, VHS1, from a black tiger shrimp-rearing pond. The VHS1 has its lysogenic relationship to the VH1114 host as either true lysogen (TL) or pseudolysogen (PL). The characters of TL are based on the extrachromosomal existence of the VHS1 phage genome in the VH host which also simultaneously produces the VHS1 phage particles and is resistant to super-infection.

Mosquito cells accommodate balanced, persistent co-infections with a densovirus and Dengue virus.

To study persistent viral co-infections in arthropods, we first produced stable, persistently infected C6/36 mosquito cell cultures by serial passage of exponentially growing whole cells infected with either a densovirus (AalDNV) or Dengue virus (DEN-2). We then obtained stable, persistent co-infections by reciprocal super-challenge and similar passaging. Persistently infected cultures did not differ from naïve-cell cultures in growth rate and cell morphology.

Unstable lysogeny and pseudolysogeny in Vibrio harveyi siphovirus-like phage 1.

Exposure of Vibrio harveyi (strain VH1114) to V. harveyi siphovirus-like phage 1 (VHS1) resulted in the production of a low percentage of lysogenized clones of variable stability. These were retrieved most easily as small colonies within dot plaques.

Synthethic peptide used to develop antibodies for detection of polyhedrin from monodon baculovirus (MBV).

The use of previously published primers to amplify the monodon baculovirus (MBV) polyhedrin gene sequence by polymerase chain reaction (PCR) from post larvae (PL) of Thai Penaeus monodon resulted in failure. As a result, the putative polyhedrin protein of MBV was isolated from infected PL by homogenization, differential centrifugation and density gradient centrifugation with verification by transmission electron microscopy (TEM). By SDS-PAGE, a single major protein band at 58 kDa was obtained from the putative polyhedrin fraction and this corresponded to a previous report of the molecular weight of polyhedrin from MBV.

Partial characterization of a novel bacteriophage of Vibrio harveyi isolated from shrimp culture ponds in Thailand.

A bacteriophage was isolated together with Vibrio harveyi (VH) 1114 a from a black tiger shrimp-rearing pond in Thailand. By negative staining transmission electron microscopy (TEM), the phage had an icosahedral head (diameter 60-62 nm), a rigid, non-contractile tail (9-10 nm x 100-120 nm) without a collar or terminal fibers and a genome of double stranded DNA of approximately 80 kb as determined by analysis of restriction enzyme digestion fragments. Since these features would place it in the family Siphoviridae, it was tentatively named V.

Multiple pathogens found in growth-retarded black tiger shrimp Penaeus monodon cultivated in Thailand.

In 2001-2002 throughout Thailand, black tiger shrimp Penaeus monodon farmers reported very unusual retarded growth. We have called this problem monodon slow growth syndrome (MSGS). Based on decreased national production, estimated losses due to this phenomenon were in the range of 13 000 million baht (approximately 300 million US dollars) in 2002.