Sample records for stylirostris densovirus pstdnv

  1. Structure of Penaeus stylirostris Densovirus, a Shrimp Pathogen

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Bärbel; Bowman, Valorie D.; Li, Yi; Szelei, Jozsef; Waddell, Peter J.; Tijssen, Peter; Rossmann, Michael G. (INRS); (Purdue)


    Penaeus stylirostris densovirus (PstDNV), a pathogen of penaeid shrimp, causes significant damage to farmed and wild shrimp populations. In contrast to other parvoviruses, PstDNV probably has only one type of capsid protein that lacks the phospholipase A2 activity that has been implicated as a requirement during parvoviral host cell infection. The structure of recombinant virus-like particles, composed of 60 copies of the 37.5-kDa coat protein, the smallest parvoviral capsid protein reported thus far, was determined to 2.5-{angstrom} resolution by X-ray crystallography. The structure represents the first near-atomic resolution structure within the genus Brevidensovirus. The capsid protein has a {beta}-barrel 'jelly roll' motif similar to that found in many icosahedral viruses, including other parvoviruses. The N-terminal portion of the PstDNV coat protein adopts a 'domain-swapped' conformation relative to its twofold-related neighbor similar to the insect parvovirus Galleria mellonella densovirus (GmDNV) but in stark contrast to vertebrate parvoviruses. However, most of the surface loops have little structural resemblance to any of the known parvoviral capsid proteins.

  2. Persistence of Penaeus stylirostris densovirus delays mortality caused by white spot syndrome virus infection in black tiger shrimp (Penaeus monodon) (United States)


    Background Persistent infection of Penaeus stylirostris densovirus (PstDNV) (also called IHHNV) and its non-infectious inserts in the black tiger shrimp, Penaeus monodon (P. monodon) genome are commonly found without apparent disease. Here, we introduced the method of multiplex PCR in order to differentiate shrimp with viral inserts from ones with the infectious virus. The method allowed us to study the effect of pre-infection of IHHNV, in comparison to IHHNV inserts, on WSSV resistance in P. monodon. Results A multiplex PCR system was developed to amplify the entire IHHNV genome, ensuring the accurate diagnosis. Field samples containing IHHNV DNA templates as low as 20 pg or equivalent 150 viral copies can be detected by this method. By challenging the two groups of diagnosed shrimp with WSSV, we found that shrimp with IHHNV infection and those with viral inserts responded to WSSV differently. Considering cumulative mortality, average time to death of shrimp in IHHNV-infected group (day 14) was significantly delayed relative to that (day 10) of IHHNV-inserted group. Real-time PCR analysis of WSSV copy number indicated the lower amount of WSSV in the IHHNV-infected group than the virus-inserted group. The ratio of IHHNV: WSSV copy number in all determined IHHNV-infected samples ranged from approximately 4 to 300-fold. Conclusion The multiplex PCR assay developed herein proved optimal for convenient differentiation of shrimp specimens with real IHHNV infection and those with insert types. Diagnosed shrimp were also found to exhibit different WSSV tolerance. After exposed to WSSV, the naturally pre-infected IHHNV P. monodon were less susceptible to WSSV and, consequently, survived longer than the IHHNV-inserted shrimp. PMID:23414329

  3. Complete Genome Sequence of a Putative Densovirus of the Asian Citrus Psyllid, Diaphorina citri. (United States)

    Nigg, Jared C; Nouri, Shahideh; Falk, Bryce W


    Here, we report the complete genome sequence of a putative densovirus of the Asian citrus psyllid, Diaphorina citri Diaphorina citri densovirus (DcDNV) was originally identified through metagenomics, and here, we obtained the complete nucleotide sequence using PCR-based approaches. Phylogenetic analysis places DcDNV between viruses of the Ambidensovirus and Iteradensovirus genera. Copyright © 2016 Nigg et al.

  4. Complete Genome Sequence of a Putative Densovirus of the Asian Citrus Psyllid, Diaphorina citri


    Nigg, Jared C.; Nouri, Shahideh; Falk, Bryce W.


    Here, we report the complete genome sequence of a putative densovirus of the Asian citrus psyllid, Diaphorina citri. Diaphorina citri densovirus (DcDNV) was originally identified through metagenomics, and here, we obtained the complete nucleotide sequence using PCR-based approaches. Phylogenetic analysis places DcDNV between viruses of the Ambidensovirus and Iteradensovirus genera.

  5. Structure and expression strategy of the genome of Culex pipiens densovirus, a mosquito densovirus with an ambisense organization. (United States)

    Baquerizo-Audiot, Elizabeth; Abd-Alla, Adly; Jousset, Françoise-Xavière; Cousserans, François; Tijssen, Peter; Bergoin, Max


    The genome of all densoviruses (DNVs) so far isolated from mosquitoes or mosquito cell lines consists of a 4-kb single-stranded DNA molecule with a monosense organization (genus Brevidensovirus, subfamily Densovirinae). We previously reported the isolation of a Culex pipiens DNV (CpDNV) that differs significantly from brevidensoviruses by (i) having a approximately 6-kb genome, (ii) lacking sequence homology, and (iii) lacking antigenic cross-reactivity with Brevidensovirus capsid polypeptides. We report here the sequence organization and transcription map of this virus. The cloned genome of CpDNV is 5,759 nucleotides (nt) long, and it possesses an inverted terminal repeat (ITR) of 285 nt and an ambisense organization of its genes. The nonstructural (NS) proteins NS-1, NS-2, and NS-3 are located in the 5' half of one strand and are organized into five open reading frames (ORFs) due to the split of both NS-1 and NS-2 into two ORFs. The ORF encoding capsid polypeptides is located in the 5' half of the complementary strand. The expression of NS proteins is controlled by two promoters, P7 and P17, driving the transcription of a 2.4-kb mRNA encoding NS-3 and of a 1.8-kb mRNA encoding NS-1 and NS-2, respectively. The two NS mRNAs species are spliced off a 53-nt sequence. Capsid proteins are translated from an unspliced 2.3-kb mRNA driven by the P88 promoter. CpDNV thus appears as a new type of mosquito DNV, and based on the overall organization and expression modalities of its genome, it may represent the prototype of a new genus of DNV.

  6. Metal and metalloid bioaccumulation in the Pacific blue shrimp Litopenaeus stylirostris (Stimpson) from New Caledonia: Laboratory and field studies

    International Nuclear Information System (INIS)

    Metian, Marc; Hedouin, Laetitia; Eltayeb, Mohamed M.; Lacoue-Labarthe, Thomas; Teyssie, Jean-Louis; Mugnier, Chantal; Bustamante, Paco; Warnau, Michel


    The present work aimed at better understanding metal and metalloid bioaccumulation in the edible Pacific blue shrimp Litopenaeus stylirostris, using both laboratory and field approaches. In the laboratory, the bioaccumulation kinetics of Ag, Cd, Co, Cr, and Zn have been investigated in shrimp exposed via seawater and food, using the corresponding γ-emitting radiotracers ( 110m Ag, 109 Cd, 57 Co, 51 Cr, and 65 Zn) and highly sensitive nuclear detection techniques. Results showed that hepatopancreas and intestine concentrated the metals to the highest extent among the blue shrimp organs and tissues. Moulting was found to play a non negligible detoxification role for Co, Cr and, to a lesser extent, Zn. Metal retention by L. stylirostris widely varied (from a few days to several months), according to the element and exposure pathway considered (a given metal was usually less strongly retained when ingested with food than when it was taken up from the dissolved phase). In the field study, Ag, As, Cd, Co, Cr, Cu, Mn, Ni, and Zn were analysed in shrimp collected from a New Caledonian aquaculture pond. Metal concentrations in the shrimp muscles were generally relatively low and results confirmed the role played by the digestive organs and tissues in the bioaccumulation/storage/detoxification of metals in the Pacific blue shrimp. Preliminary risk considerations indicate that consumption of the shrimp farmed in New Caledonia is not of particular concern for human health.

  7. Factors influencing infection and transmission of Anopheles gambiae densovirus (AgDNV in mosquitoes

    Directory of Open Access Journals (Sweden)

    Tapan K. Barik


    Full Text Available Anopheles gambiae densovirus (AgDNV is a potential microbial agent for paratransgenesis and gene transduction in An. gambiae, the major vector of human malaria in sub-Saharan Africa. Understanding the interaction between AgDNV and An. gambiae is critical for using AgDNV in a basic and applied manner for Anopheles gene manipulation. Here, we tested the effects of mosquito age, sex, blood feeding status, and potential for horizontal transmission using an enhanced green fluorescent protein (EGFP reporter AgDNV system. Neither mosquito age at infection nor feeding regime affected viral titers. Female mosquitoes were more permissive to viral infection than males. Despite low viral titers, infected males were able to venereally transmit virus to females during mating, where the virus was localized with the transferred sperm in the spermathecae. These findings will be useful for designing AgDNV-based strategies to manipulate Anopheles gambiae.

  8. Factors influencing infection and transmission of Anopheles gambiae densovirus (AgDNV) in mosquitoes. (United States)

    Barik, Tapan K; Suzuki, Yasutsugu; Rasgon, Jason L


    Anopheles gambiae densovirus (AgDNV) is a potential microbial agent for paratransgenesis and gene transduction in An. gambiae , the major vector of human malaria in sub-Saharan Africa. Understanding the interaction between AgDNV and An. gambiae is critical for using AgDNV in a basic and applied manner for Anopheles gene manipulation. Here, we tested the effects of mosquito age, sex, blood feeding status, and potential for horizontal transmission using an enhanced green fluorescent protein (EGFP) reporter AgDNV system. Neither mosquito age at infection nor feeding regime affected viral titers. Female mosquitoes were more permissive to viral infection than males. Despite low viral titers, infected males were able to venereally transmit virus to females during mating, where the virus was localized with the transferred sperm in the spermathecae. These findings will be useful for designing AgDNV-based strategies to manipulate Anopheles gambiae .

  9. Does damming of the Colorado River affect the nursery area of blue shrimp Litopenaeus stylirostris (Decapoda: Penaeidae in the Upper Gulf of California?

    Directory of Open Access Journals (Sweden)

    Eugenio Alberto Aragón-Noriega


    Full Text Available After damming the Colorado River the freshwater flow was reduced to 1 % of its virgin flow to the Upper Gulf of California (UGC. The ecological effects need to be properly documented. The UGC is the nursery area for Litopenaeus stylirostris, the most profitable fishery in the zone. In order to know the relative abundance of L. stylirostris postlarval stage we conducted a sampled survey every 14 days in 1993, 1994 and 1997, plus an intensive sampling during a complete tide cycle in July 1995 and 1996. We did 10 min trawls each hour during the flood tide. Relative abundance of postlarvae was higher (pEl represamiento del Río Colorado ha ocasionado que el flujo de agua dulce sobre el Alto Golfo de California (AGC se haya reducido hasta el 1 % del flujo original. Se ha documentado el efecto de la reducción de agua dulce sobre las condiciones hidrográficas del AGC, pero las repercusiones ecológicas no se han descrito apropiadamente. El AGC ha sido área de crianza para especies comerciales como el camarón Litopenaeus stylirostris. Se hicieron recolectas de postlarvas de L. stylirostris en el AGC durante cinco años consecutivos. Los muestreos fueron catorcenalmente en los años de 1993, 1994 y 1997 y se realizó una recolecta diaria durante 15 días consecutivos en los años 1995 y 1996. Para ello se arrastró una red de plancton de 505 µ durante 10 min cada hora durante el flujo de marea. La abundancia relativa de las postlarvas de camarón en esta zona viaria considerablemente en años cuando el flujo de agua dulce incrementa. La abundancia es mayor hasta en un 200 % (p < 0.05 cuando existe descarga de agua dulce al AGC.

  10. Genetic, biochemical, and structural characterization of a new densovirus isolated from a chronically infected Aedes albopictus C6/36 cell line

    International Nuclear Information System (INIS)

    Chen Senxiong; Cheng Lingpeng; Zhang Qinfen; Lin Wei; Lu Xinying; Brannan, Jennifer; Zhou, Z.H.; Zhang Jingqiang


    We report the isolation, sequencing, biochemical, and structural characterization of a previously undescribed virus in a chronically infected Aedes albopictus C6/36 cell line. This virus is identified as a new densovirus under the Densovirinae subfamily of the Parvoviridae based on its biological and morphologic properties as well as sequence homologies, and is tentatively designated A. albopictus C6/36 cell densovirus (C6/36 DNV). Analysis of the 4094 nt of the C6/36 DNV genome revealed that the plus strand had three large open reading frames (ORFs): a left ORF, a right ORF, and a mid-ORF (within the left ORF), whose potential coding capacities are 91.0, 40.8, and 41.2 kDa, respectively. The left ORF likely encodes the nonstructural protein NS-1, which contains NTP-binding and helicase domains. The right ORF likely encodes structural proteins, VP1 and VP2. Our analyses revealed that C6/36 DNV has a similar genomic organization and shares very high homology in nucleotide sequence and amino acid sequences with Aedes aegypti densovirus (AaeDNV) and A. albopictus densovirus (AalDNV), members of the genus Brevidensovirus of the Densovirinae. Similar to other densoviruses, C6/36 DNV has a different genomic organization and no recognizable sequence homology with viruses in the Parvovirinae. The three-dimensional (3D) reconstruction of the C6/36 DNV at 15.6-A resolution by electron cryomicroscopy (cryoEM) revealed distinctive outer surface features not previously seen in other parvoviruses, indicating structural divergence of densoviruses, in addition to its genomic differences, while the inner surface of the C6/36 DNV capsid exhibits features that are conserved among parvoviruses

  11. Quality changes during frozen storage of blue shrimp (Litopenaeus stylirostris with antioxidant, α-tocopherol, under different conditions

    Directory of Open Access Journals (Sweden)

    Adriana Zulema Valencia-Perez


    Full Text Available Fresh blue shrimp (Litopenaeus stylirostris muscle was stored with antioxidants under different conditions: ANTIOX 2%, packed in bilayer film of polyamide-low density polyethylene film (PA-LDPE with 2% α-tocopherol; ANTIOX 4%, packed in PA-LDPE film with 4% α-tocopherol; and ANTIOX-GLAZED, samples stored glazed with 2% α-tocopherol. Shrimps packed in PA-LDPE without α-tocopherol were used as CONTROL. All samples were stored at –20 °C for 120 days. As compared to the CONTROL, the shrimp stored with the antioxidant showed lower lipid oxidation (0.10-0.14 vs 1.58 mgMA/kg of muscle, lost less firmness and astaxanthin content. ANTIOX 2% and ANTIOX-GLAZED showed the lowest concentrations of formaldehyde (0.081-0.083 μM/g. There were no significant differences in color and sensory properties, but differences in the integrity of the muscle fibers were observed. The treatments with α-tocopherol maintained the shrimp muscle quality during frozen storage. However, no significant differences were found between these treatments.

  12. Primer registro de la utilización de harinas de Salicornia bigelovii y Scomber japonicus en dietas prácticas para el cultivo súper-intensivo de camarón Litopenaeus stylirostris First record on the use of Salicornia bigelovii and Scomber japonicus fishmeals as feed for Litopenaeus stylirostris under super-intensive farming

    Directory of Open Access Journals (Sweden)

    Manuel de J . Acosta-Ruiz


    Full Text Available Se evaluó el efecto de las harinas de Salicornia bigelovii (SA y Scomber japonicus, semiprocesada (HPS como ingredientes en la formulación de dietas para camarón azul Litopenaeus stylirostris, en cultivo súper-intensivo. Se formularon tres diferentes dietas isoproteicas (40% e isocalóricas (6 kcal g-1: (DSA, (DHPS, basal (DBA y una dieta control (DCO. El peso obtenido con DSA y DHPS (0,9 ± 0,014 y 0,8 ± 0,015 g fue similar a la dieta comercial DCO (0,9 ± 0,07 g, no existieron diferencias significativas (P > 0,05 en talla (cm, peso (g y factor de conversión alimenticio (FCA. Los resultados obtenidos sugieren que DSA y DHPS son factibles de utilizar en la formulación de dietas para camarón por ser ingredientes de bajo costo que pueden sustituir a la harina de maíz y pescado tradicional, respectivamente sin efectos detrimentales en el crecimiento y supervivencia.The effect of semi-processed fishmeals (HPS made using Salicornia bigelovii (SA and Scomber japonicusas ingredients in the formulation of diets for blue shrimp Litopenaeus stylirostris undersuper-intensive farming was evaluated. Three different isoproteinic (40% and isocaloric (6 kcal g-1 diets were formulated: DSA, DHPS, basal (DBA; a fourth control diet (DCO was also used. The weights obtained with DSA and DHPS (0.9 ± 0.014 and 0.8 ± 0.015 g were similar to those obtained with the commercial diet (DCO; 0.9 ± 0.07 g, and no significant differences (P > 0.05 were found for size (cm, weight (g, and the feed conversion ratio (FCR. The results suggest that the use of DSA and DHPS in the formulation of diets for shrimp is feasibleas these are low-cost ingredients that can be used as substitutes for cornstarch and traditional fishmeal, respectively, without detrimental effects for shrimp growth and survival.

  13. Structure and transcription of the Helicoverpa armigera densovirus (HaDV2) genome and its expression strategy in LD652 cells. (United States)

    Xu, Pengjun; Graham, Robert I; Wilson, Kenneth; Wu, Kongming


    Densoviruses (DVs) are highly pathogenic to their hosts. However, we previously reported a mutualistic DV (HaDV2). Very little was known about the characteristics of this virus, so herein we undertook a series of experiments to explore the molecular biology of HaDV2 further. Phylogenetic analysis showed that HaDV2 was similar to members of the genus Iteradensovirus. However, compared to current members of the genus Iteradensovirus, the sequence identity of HaDV2 is less than 44% at the nucleotide-level, and lower than 36, 28 and 19% at the amino-acid-level of VP, NS1 and NS2 proteins, respectively. Moreover, NS1 and NS2 proteins from HaDV2 were smaller than those from other iteradensoviruses due to their shorter N-terminal sequences. Two transcripts of about 2.2 kb coding for the NS proteins and the VP proteins were identified by Northern Blot and RACE analysis. Using specific anti-NS1 and anti-NS2 antibodies, Western Blot analysis revealed a 78 kDa and a 48 kDa protein, respectively. Finally, the localization of both NS1 and NS2 proteins within the cell nucleus was determined by using Green Fluorescent Protein (GFP) labelling. The genome organization, terminal hairpin structure, transcription and expression strategies as well as the mutualistic relationship with its host, suggested that HaDV2 was a novel member of the genus Iteradensovirus within the subfamily Densovirinae.

  14. Cloning and characterization of the densoviruses susceptible gene ...

    African Journals Online (AJOL)



    Jun 21, 2010 ... was located on genetic linkage 15 (Qin and Yi, 1996). Li .... The tree distances were generated according to the ClustalW algorithm and the tree was constructed using ... Foundation of China (30871826), China National ''863''.

  15. Effects of pesticides on DNA and protein of shrimp larvae Litopenaeus stylirostris of the California Gulf. (United States)

    Galindo Reyes, J Guillermo; Leyva, Nancy R; Millan, Olivia A; Lazcano, Guadalupe A


    Recently, diverse pathologies and massive mortalities have been presented in shrimp hatcheries located along the California Gulf; therefore, toxic responses of shrimp larvae were used as biomarkers of pesticide pollution, because in this region intensive agriculture is practiced. Shrimp larvae were exposed to DDT, azinphosmethyl, permethrine, parathion, chlorpyrifos, malathion, endosulfan, and carbaryl, in order to determine LC50, DNA adducts and/or breaks, and total protein in larvae. The results indicate reductions in protein and DNA in larvae exposed to these pesticides, and in those exposed to DDT, breaks and/or adducts were registered. It is possible that pesticide pollution is a cause of these problems, because reduction in protein indicates a decrease in larvae growth rate and DNA breaks or adducts have been related to pathologies and carcinogenesis in many aquatic organisms.

  16. Use of cDNA microarray to isolate differentially expressed genes in White Spot Virus infected shrimp (penaeus stylirostris)


    Dhar, Arun K.; Klimpel, Kurt R.; Bullis, Robert A.; McClenaghan, Leroy R.


    White spot syndrome virus (WSSV), the etiologic agent of white spot disease, is currently the most important viral pathogen infecting penaeid shrimp worldwide. Since the initial report, white spot disease has caused losses of catastrophic proportion to shrimp aquaculture globally. Although considerable progress has been made in characterizing the WSSV and developing detection methods, information on the host genes involved in the immune response in shrimp due to WSSV infection is not availabl...

  17. Insect cell transformation vectors that support high level expression and promoter assessment in insect cell culture (United States)

    A somatic transformation vector, pDP9, was constructed that provides a simplified means of producing permanently transformed cultured insect cells that support high levels of protein expression of foreign genes. The pDP9 plasmid vector incorporates DNA sequences from the Junonia coenia densovirus th...

  18. Prevalencia y distribución de los principales agentes etiológicos que afectan los langostinos silvestres en Tumbes, Perú

    Directory of Open Access Journals (Sweden)

    Rubén Alfaro Aguilera


    Full Text Available Se determinó la prevalencia y distribución de diferentes agentes patógenos en langostinos silvestres, en la zona de esteros de la Región Tumbes - Perú, entre marzo y diciembre de 2009. Los canales de marea considerados en este estudio fueron: Boca del Río Tumbes, El Alcalde, Jelí, El Bendito, Envidia, Soledad y Algarrobo. Se colectó un total de 1926 langostinos entre juveniles y pre-adultos de las especies Litopenaeus vannamei, L. stylirostris y Farfantepenaeus californiensis. Utilizando la técnica de la PCR, se detectó la presencia de los patógenos NHPB (0,62%, IHHNV (0,31%, BP (1,61% y WSV (2,75%; no se encontró infección por TSV. Las tres especies en estudio fueron positivas a WSV y BP, presentándose la mayor prevalencia de infección por WSV (2,98% en la especie L. stylirostris y por BP (2,66% en L. vannamei. La NHPB fue detectada en las especies L. vannamei y L. stylirostris con 0,77% y 0,43% de prevalencia respectivamente. Se obtuvo una prevalencia de 0,52% para IHHNV en L. vannamei. Las más altas prevalencias de las infecciones por WSV, BP, NHPB e IHHNV se registraron en los canales de marea El Alcalde (10,79%, Algarrobo (4,51%, Envidia (2,26% y Jelí (5,05%. Los datos señalan la presencia constante de diversos patógenos virales y bacterianos en diferentes especies de peneidos y su amplia distribución a lo largo del litoral tumbesino, lo que constituye un riesgo potencial para el desarrollo de la acuicultura en la región, y podría afectar las poblaciones naturales de langostinos.

  19. Pollution by polycyclic aromatic hydrocarbons (PAH's) in sediments and organisms from Salina Cruz Port, Oaxaca, Mexico

    International Nuclear Information System (INIS)

    Botello, A.V.; Villanueva, S.; Diaz, G.; Pica, Y.


    The presence and levels of polycyclic aromatic hydrocarbons (PAH's) in [sediments and biota from the Port of Salina Cruz, Oaxaca; were evaluated by means of gas capillary chromatography using columns of high resolution. The results show a seasonal variability of the PAH's concentrations in sediments being higher in the port area and lower in oceanic sediments. The increase of the PAH's levels in Crassostrea iridiscens and Penaeus stylirostris is important and related to the bioaccumulation process. The presence of PAH's conformed by 4 y 5 benzene rings in these species must be noted specially because they have carcinogenic properties and their effects on the local fisheries should be considered. (Author)

  20. Genotyping of white spot syndrome virus on wild and farm crustaceans from Sonora, Mexico

    Directory of Open Access Journals (Sweden)

    González-Galaviz José Reyes


    Full Text Available White spot syndrome is a viral disease affecting wild and farm crustaceans that serve as reservoirs. Previous reports have demonstrated high genomic variation in WSS viruses (WSSV isolated from distinct geographical regions. In this study, we collected wild shrimps (Litopenaeus stylirostris, crabs (Callinectes arcuatus and farmed shrimp (L. vannamei in Sonora, Mexico, between 2008 and 2010. DNA was extracted, and the variable regions and transposase genes were subjected to PCR and sequencing. Compared to strains of WSSV from other sites, Mexican samples exhibited a distinct number of repeat units (RUs in ORF94, ORF75 and ORF125, which ranged between 1-11, 3-15, and 8-11 RUs respectively, and a unique single nucleotide polymorphism (SNP at position 48 of ORF94. A total of six Mexican genotypes were found in organism from shrimp farm and natural environment.

  1. The structure and host entry of an invertebrate parvovirus. (United States)

    Meng, Geng; Zhang, Xinzheng; Plevka, Pavel; Yu, Qian; Tijssen, Peter; Rossmann, Michael G


    The 3.5-Å resolution X-ray crystal structure of mature cricket parvovirus (Acheta domesticus densovirus [AdDNV]) has been determined. Structural comparisons show that vertebrate and invertebrate parvoviruses have evolved independently, although there are common structural features among all parvovirus capsid proteins. It was shown that raising the temperature of the AdDNV particles caused a loss of their genomes. The structure of these emptied particles was determined by cryo-electron microscopy to 5.5-Å resolution, and the capsid structure was found to be the same as that for the full, mature virus except for the absence of the three ordered nucleotides observed in the crystal structure. The viral protein 1 (VP1) amino termini could be externalized without significant damage to the capsid. In vitro, this externalization of the VP1 amino termini is accompanied by the release of the viral genome.

  2. History and Current Status of Development and Use of Viral Insecticides in China

    Directory of Open Access Journals (Sweden)

    Xiulian Sun


    Full Text Available The use of insect viruses as biological control agents started in the early 1960s in China. To date, more than 32 viruses have been used to control insect pests in agriculture, forestry, pastures, and domestic gardens in China. In 2014, 57 products from 11 viruses were authorized as commercial viral insecticides by the Ministry of Agriculture of China. Approximately 1600 tons of viral insecticidal formulations have been produced annually in recent years, accounting for about 0.2% of the total insecticide output of China. The development and use of Helicoverpa armigera nucleopolyhedrovirus, Mamestra brassicae nucleopolyhedrovirus, Spodoptera litura nucleopolyhedrovirus, and Periplaneta fuliginosa densovirus are discussed as case studies. Additionally, some baculoviruses have been genetically modified to improve their killing rate, infectivity, and ultraviolet resistance. In this context, the biosafety assessment of a genetically modified Helicoverpa armigera nucleopolyhedrovirus is discussed.

  3. Explotación de la pesquería de arrastre de camarón durante el período 1991-1999 en el Golfo de Nicoya, Costa Rica

    Directory of Open Access Journals (Sweden)

    Farid A Tabash Blanco


    Full Text Available En Costa Rica, la pesquería del camarón que se lleva a cabo en el Golfo de Nicoya desde 1952 representó una de las más importantes actividades económicas de la región. Sin embargo, la sobrepesca redujo los volúmenes de captura al punto de impedir esta actividad comercial. Con el objetivo de evaluar su evolución durante la pasada década y compararla con los registros históricos de captura, se analizaron las estadísticas pesqueras oficiales comprendidas entre 1991 y 1999 para las especies de camarón que se capturan: dos especies de camarón blanco (Litopenaeus occidentalis y L. stylirostris, el camarón tití (Xiphopenaeus riveti, el camarón café (Farfantepenaeus californiensis, el camarón "pinki" (F. brevirostris y el camarón fidel (Solenocera agassizi. Todas las especies analizadas presentaron un alto nivel de sobre-explotación, lo que provoca un aumento en la demanda de reclutas de camarón requeridos para tratar de reponer a los que son capturados por la flota arrastre. En consecuencia, la edad de primera captura ha disminuido exponencialmente. Se recomienda vedar totalmente la pesca de arrastre del camarón en el Golfo de Nicoya.Exploitation of the shrimp trawl fishery in the period 1991-1999 at the Gulf of Nicoya, Costa Rica. In Costa Rica, the Gulf of Nicoya shrimp fishery originated in 1952 and represented one of the most important economic activities in the region. Nevertheless, overfishery reduced the captured volumes to levels that prevent this commercial activity. I analyzed official fishery statistics between 1991 and 1999. These species involved are: two species of white shrimp, (Litopenaeus occidentalis and L. stylirostris, the "tití" shrimp (Xiphopenaeus riveti, the brown shrimp (Farfantepenaeus californiensis, the "pinki" shrimp (F. brevirostris and the "fidel" shrimp (Solenocera agassizi. All the species reached the Maximum Sustainable Yield in the decades of 1970 and 1980 and are now found at over

  4. cDNA cloning, characterization and expression analysis of a novel antimicrobial peptide gene penaeidin-3 (Fi-Pen3) from the haemocytes of Indian white shrimp Fenneropenaeus indicus. (United States)

    Shanthi, S; Vaseeharan, B


    A new member of antimicrobial peptide genes of the penaeidin family, penaeidin 3, was cloned from the haemocytes of Indian white shrimp Fenneropeneaus indicus (F. indicus), by reverse transcription PCR (RT-PCR) and rapid amplification of cDNA end (RACE-PCR) methods. The complete nucleotide sequence of cDNA clone of Indian white shrimp F. indicus Penaeidin 3 (Fi-Pen3) was 243bp long and has an open reading frame which encodes 80 amino acid peptide. The homology analysis of Fi-Pen3 sequence with other Penaeidins 3 shows higher similarity with Penaeus monodon (92%). The theoretical 3D structure generated through ab initio modelling indicated the presence of two-disulphide bridges in the alpha-helix. The signal peptide sequence of Fi-Pen3 is almost entirely homologous to that of other Penaeidin 3 of crustaceans, while differing relatively in the N-terminal domain of the mature peptide. The mature peptide has a predicted molecular weight of 84.9kDa, and a theoretical pI of 9.38. Phylogenetic analysis of Fi-Pen3 shows high resemblance with other Pen-3 from P. monodon, Litopenaeus stylirostris, Litopenaeus vannamei and Litopenaeus setiferus. Fi-Pen3 found to be expressed in haemocytes, heart, hepatopancreas, muscles, gills, intestine, and eyestalk with higher expression in haemocytes. Microbial challenge resulted in mRNA up-regulation, up to 6h post injection of Vibrio parahemolyticus. The Fi-Pen3 mRNA expression of F. indicus in the premolt stage (D(01) and D(02)) was significantly up-regulated than the postmolt (A and B) and intermolt stages (C). The findings of the present paper underline the involvement of Fi-Pen3 in innate immune system of F. indicus. Copyright © 2011 Elsevier GmbH. All rights reserved.

  5. Sea Star Wasting Disease 2 Years On: What We know, What We Don't Yet Know, and What We are Doing Now to Understand the Disease (United States)

    Hewson, I.


    Sea star wasting disease has affected over 20 species of asterozoa in waters from central Alaska to Baja California, causing extensive mortality and disappearance entirely from some areas. Combined viral, bacterial, eukaryotic microbial, and histological investigations identified the core nano- and micro-biome of sea stars, and elucidated that the Sea Star Associated Densovirus (SSaDV) was the most likely candidate microorganism involved in disease etiology. Direct challenge experiments using tissue homogenates from symptomatic animals injected into asymptomatic individuals revealed that the disease is caused by a virus-sized entity. However, there remains much to be learned about the disease, especially how disease symptoms are generated by SSaDV, how the virus is transmitted between infected and uninfected animals, and why SSaDV may cause disease recently. We performed inoculation trials on SSaDV-naïve sea stars collected from a geographically distant population away from disease-affected areas, and observed viral, bacterial, archaeal, and host transcriptomic responses over time. We also performed surveys of SSaDV in juveniles and larval plankton, as well as the environmental distribution and stability of SSaDV in key regions where SSWD has all but wiped out adults. Our results suggest that SSaDV must move around either on particles or by direct contact between animals, since decay rates exceed reasonable transmission times based on sea star abundance. Global surveys of sea star-associated viruses also elucidate that SSaDV may have been present in populations of sea stars from Hong Kong around the same time of the 2013-2015 epidemic.

  6. Cameroonian fruit bats harbor divergent viruses, including rotavirus H, bastroviruses, and picobirnaviruses using an alternative genetic code. (United States)

    Yinda, Claude Kwe; Ghogomu, Stephen Mbigha; Conceição-Neto, Nádia; Beller, Leen; Deboutte, Ward; Vanhulle, Emiel; Maes, Piet; Van Ranst, Marc; Matthijnssens, Jelle


    Most human emerging infectious diseases originate from wildlife and bats are a major reservoir of viruses, a few of which have been highly pathogenic to humans. In some regions of Cameroon, bats are hunted and eaten as a delicacy. This close proximity between human and bats provides ample opportunity for zoonotic events. To elucidate the viral diversity of Cameroonian fruit bats, we collected and metagenomically screened eighty-seven fecal samples of Eidolon helvum and Epomophorus gambianus fruit bats. The results showed a plethora of known and novel viruses. Phylogenetic analyses of the eleven gene segments of the first complete bat rotavirus H genome, showed clearly separated clusters of human, porcine, and bat rotavirus H strains, not indicating any recent interspecies transmission events. Additionally, we identified and analyzed a bat bastrovirus genome (a novel group of recently described viruses, related to astroviruses and hepatitis E viruses), confirming their recombinant nature, and provide further evidence of additional recombination events among bat bastroviruses. Interestingly, picobirnavirus-like RNA-dependent RNA polymerase gene segments were identified using an alternative mitochondrial genetic code, and further principal component analyses suggested that they may have a similar lifestyle to mitoviruses, a group of virus-like elements known to infect the mitochondria of fungi. Although identified bat coronavirus, parvovirus, and cyclovirus strains belong to established genera, most of the identified partitiviruses and densoviruses constitute putative novel genera in their respective families. Finally, the results of the phage community analyses of these bats indicate a very diverse geographically distinct bat phage population, probably reflecting different diets and gut bacterial ecosystems.

  7. Viral diseases of marine invertebrates (United States)

    Johnson, P. T.


    Penaeus and causes catastrophic mortalities in P. stylirostris, but usually exhibits only inapparent infection in P. vannamei. Some shrimp viruses apparently are latent in larvae, causing disease only when shrimp have reached the postlarval or juvenile stages. Others are equally or more pathogenic in larvae. Studies of shrimp viruses and iridovirus-associated disease in cultured oysters point up the need for rapid and accurate diagnostic methods. Until appropriate cell cultures from marine invertebrates are devised, the viral identifications necessary for understanding of epizootiology, rapid containment of epizootics in cultured animals, and decisions regarding introductions of exotic species will be difficult or impossible.

  8. Development of duplex real-time PCR for the detection of WSSV and PstDV1 in cultivated shrimp. (United States)

    Leal, Carlos A G; Carvalho, Alex F; Leite, Rômulo C; Figueiredo, Henrique C P


    The White spot syndrome virus (WSSV) and Penaeus stylirostris penstyldensovirus 1 (previously named Infectious hypodermal and hematopoietic necrosis virus-IHHNV) are two of the most important viral pathogens of penaeid shrimp. Different methods have been applied for diagnosis of these viruses, including Real-time PCR (qPCR) assays. A duplex qPCR method allows the simultaneous detection of two viruses in the same sample, which is more cost-effective than assaying for each virus separately. Currently, an assay for the simultaneous detection of the WSSV and the PstDV1 in shrimp is unavailable. The aim of this study was to develop and standardize a duplex qPCR assay for the simultaneous detection of the WSSV and the PstDV1 in clinical samples of diseased L. vannamei. In addition, to evaluate the performance of two qPCR master mixes with regard to the clinical sensitivity of the qPCR assay, as well as, different methods for qPCR results evaluation. The duplex qPCR assay for detecting WSSV and PstDV1 in clinical samples was successfully standardized. No difference in the amplification of the standard curves was observed between the duplex and singleplex assays. Specificities and sensitivities similar to those of the singleplex assays were obtained using the optimized duplex qPCR. The analytical sensitivities of duplex qPCR were two copies of WSSV control plasmid and 20 copies of PstDV1 control plasmid. The standardized duplex qPCR confirmed the presence of viral DNA in 28 from 43 samples tested. There was no difference for WSSV detection using the two kits and the distinct methods for qPCR results evaluation. High clinical sensitivity for PstDV1 was obtained with TaqMan Universal Master Mix associated with relative threshold evaluation. Three cases of simultaneous infection by the WSSV and the PstDV1 were identified with duplex qPCR. The standardized duplex qPCR was shown to be a robust, highly sensitive, and feasible diagnostic tool for the simultaneous detection of the

  9. Differential bioaccumulation of "1"3"4Cs in tropical marine organisms and the relative importance of exposure pathways

    International Nuclear Information System (INIS)

    Metian, Marc; Pouil, Simon; Hédouin, Laetitia; Oberhänsli, François; Teyssié, Jean-Louis; Bustamante, Paco; Warnau, Michel


    Bioaccumulation of "1"3"4Cs was determined in 5 tropical marine species: three bivalves (the oysters Isognomon isognomum and Malleus regula, and the clam Gafrarium pectinatum), one decapod (shrimp Penaeus stylirostris) and one alga (Lobophora variegata). Marine organisms were exposed to the radionuclides via different pathways: seawater (all of them), food (shrimp and bivalves) and sediment (bivalves). Our results indicate that the studied tropical species accumulate Cs similarly than species from temperate regions whereas retention capacities seems to be greater in the tropical species. Bioaccumulation capacities of the two oysters were similar for all the exposure pathways. The alga, and to a lesser extent the shrimp, concentrated dissolved Cs more efficiently than the bivalves (approx. 14 and 7 times higher, respectively). Assimilation efficiencies of Cs in bivalves and shrimp after a single feeding with radiolabelled food were comprised between 7.0 ± 0.4 and 40.7 ± 4.3%, with a variable retention time (half-life –T_b_1_/_2– ranging from 16 ± 3 to 89 ± 55 d). Although the clam lives buried in the sediment, this exposure pathway resulted in low bioaccumulation efficiency for sediment-bound Cs (mean transfer factor: 0.020 ± 0.001) that was lower than the two oyster species, which are not used to live in this media (0.084 ± 0.003 and 0.080 ± 0.005). Nonetheless, Cs accumulated from sediment was similarly absorbed (61.6 ± 9.7 to 79.2 ± 2.3%) and retained (T_b_1_/_2: 37 ± 2 to 58 ± 25 d) for the three bivalves species. Despite the poor transfer efficiency of Cs from food, the use of a global bioaccumulation model indicated that the trophic pathways was the main uptake route of Cs in the bivalves and shrimp. In shelled organisms, shells played a non-negligible role in Cs uptake, and their composition and structure might play a major role in this process. Indeed, most of the Cs taken up from seawater and sediment was principally