Acute hepatopancreatic necrosis disease (AHPND) is a severe, newly emergent penaeid shrimp disease caused by Vibrio parahaemolyticus that has already led to tremendous losses in the cultured shrimp ...industry. Until now, its disease-causing mechanism has remained unclear. Here we show that an AHPND-causing strain of V. parahaemolyticus contains a 70-kbp plasmid (pVA1) with a postsegregational killing system, and that the ability to cause disease is abolished by the natural absence or experimental deletion of the plasmid-encoded homologs of the Photorhabdus insect-related (Pir) toxins PirA and PirB. We determined the crystal structure of the V. parahaemolyticus PirA and PirB (PirA(vp) and PirB(vp)) proteins and found that the overall structural topology of PirA(vp)/PirB(vp) is very similar to that of the Bacillus Cry insecticidal toxin-like proteins, despite the low sequence identity (<10%). This structural similarity suggests that the putative PirAB(vp) heterodimer might emulate the functional domains of the Cry protein, and in particular its pore-forming activity. The gene organization of pVA1 further suggested that pirAB(vp) may be lost or acquired by horizontal gene transfer via transposition or homologous recombination.
Asian countries are the major producers of cultured Penaeid shrimps such as Penaeus monodon and Penaeus (Litopenaeus) vannamei. In recent years, shrimp production has declined due to the emergence of ...a bacterial disease called acute hepatopancreatic necrosis disease (AHPND). This disease is mainly caused by Vibrio parahaemolyticus, but other Vibrio species are also known to cause AHPND in shrimps. Here, in addition to reviewing recent developments in the field of AHPND diagnosis, host responses to AHPND, the role of microbiota during AHPND infection and the current treatment options for AHPND, we also describe a model of AHPND pathogenesis.
Photorhabdus insect-related toxins A and B (PirA and PirB) were first recognized as insecticidal toxins from Photorhabdus luminescens. However, subsequent studies showed that their homologs from ...Vibrio parahaemolyticus also play critical roles in the pathogenesis of acute hepatopancreatic necrosis disease (AHPND) in shrimps. Based on the structural features of the PirA/PirB toxins, it was suggested that they might function in the same way as a Bacillus thuringiensis Cry pore-forming toxin. However, unlike Cry toxins, studies on the PirA/PirB toxins are still scarce, and their cytotoxic mechanism remains to be clarified. In this review, based on our studies of V. parahaemolyticus PirAvp/PirBvp, we summarize the current understanding of the gene locations, expression control, activation, and cytotoxic mechanism of this type of toxin. Given the important role these toxins play in aquatic disease and their potential use in pest control applications, we also suggest further topics for research. We hope the information presented here will be helpful for future PirA/PirB studies.
Acute hepatopancreatic necrosis disease (AHPND) (formerly, early mortality syndrome) is a high-mortality-rate shrimp disease prevalent in shrimp farming areas. Although AHPND is known to be caused by ...pathogenic Vibrio parahaemolyticus hosting the plasmid-related PirAB
toxin gene, the effects of disturbances in microbiome have not yet been studied. We took 62 samples from a grow-out pond during an AHPND developing period from Days 23 to 37 after stocking white postlarvae shrimp and sequenced the 16S rRNA genes with Illumina sequencing technology. The microbiomes of pond seawater and shrimp stomachs underwent varied dynamic succession during the period. Despite copies of PirAB
, principal co-ordinates analysis revealed two distinctive stages of change in stomach microbiomes associated with AHPND. AHPND markedly changed the bacterial diversity in the stomachs; it decreased the Shannon index by 53.6% within approximately 7 days, shifted the microbiome with Vibrio and Candidatus Bacilloplasma as predominant populations, and altered the species-to-species connectivity and complexity of the interaction network. The AHPND-causing Vibrio species were predicted to develop a co-occurrence pattern with several resident and transit members within Candidatus Bacilloplasma and Cyanobacteria. This study's insights into microbiome dynamics during AHPND infection can be valuable for minimising this disease in shrimp farming ponds.
The Pathobiome in Animal and Plant Diseases Bass, David; Stentiford, Grant D.; Wang, Han-Ching ...
Trends in ecology & evolution (Amsterdam),
November 2019, 2019-11-00, 20191101, Volume:
34, Issue:
11
Journal Article
Peer reviewed
Open access
A growing awareness of the diversity and ubiquity of microbes (eukaryotes, prokaryotes, and viruses) associated with larger ‘host’ organisms has led to the realisation that many diseases thought to ...be caused by one primary agent are the result of interactions between multiple taxa and the host. Even where a primary agent can be identified, its effect is often moderated by other symbionts. Therefore, the one pathogen–one disease paradigm is shifting towards the pathobiome concept, integrating the interaction of multiple symbionts, host, and environment in a new understanding of disease aetiology. Taxonomically, pathobiomes are variable across host species, ecology, tissue type, and time. Therefore, a more functionally driven understanding of pathobiotic systems is necessary, based on gene expression, metabolic interactions, and ecological processes.
Animal and plant diseases are increasingly recognised to result from interactions between host-associated bacteria, eukaryotes, and viruses, their host, and the environment.The diversity and function of host-associated organisms are diverse and incompletely understood.Multidisciplinary studies, including high-throughput sequencing ‘omics, can be used to reveal both the structure and function of pathobiomes, which may not be discernible from taxonomic analyses alone.Both ‘normal’ and ‘disease’ pathobiomes vary over time and between host tissues and organs.Understanding pathobiotic systems presents not only challenges to current disease diagnostic practices and legislation associated with this, but also diverse new opportunities for mitigating disease and optimising on-farm growing conditions.
A Technical Overview of AV1 Han, Jingning; Li, Bohan; Mukherjee, Debargha ...
Proceedings of the IEEE,
09/2021, Volume:
109, Issue:
9
Journal Article
Peer reviewed
Open access
The AV1 video compression format is developed by the Alliance for Open Media consortium. It achieves more than a 30% reduction in bit rate compared to its predecessor VP9 for the same decoded video ...quality. This article provides a technical overview of the AV1 codec design that enables the compression performance gains with considerations for hardware feasibility.
Microbial volatile organic compounds (mVCs) are formed in the metabolism of microorganisms and widely distributed in nature and pose threats to human health. However, the air pollution by ...microorganisms is a situation which is poorly understood. In this study, the cytotoxicity of E. aerogenes VCs was evaluated in the model organism Saccharomyces cerevisiae. E. aerogenes VCs inhibited the survival of yeast and triggered the formation of intracellular reactive oxygen species (ROS). The hypersensitive of MAP kinase mpk1/slt2 and 19S regulatory assembly chaperone adc17 mutants to the E. aerogenes VCs indicated cell wall integrity (CWI) pathway together with stress-inducible proteasome assembly regulation are essentially involved in mVCs tolerance mechanism. Furthermore, exposure to the mVCs resulted in the transcriptional upregulation of the CWI pathway, the regulatory particle assembly chaperones, and genes involved in proteasome regulations. Our research suggested that the ROS/MAPK signaling and proteasome regulatory pathway play pivotal roles in the integration and fine-tuning of the mVCs stress response. This study provides a molecular framework for future study of the effects of mVCs on more complex organisms, such as humans.
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•MVCs impose toxicity to yeast by oxdative stress.•Mpk1/Slt2 protects yeast cell from mVCs toxicity.•The exposure of mVCs affects CWI pathway in yeast.•Proteasome homeostasis is required for mVCs stress tolerance in yeast.
Shrimp white spot disease (WSD), which is caused by white spot syndrome virus (WSSV), is one of the world's most serious shrimp diseases. Our objective in this study was to use an immunomagnetic ...reduction (IMR) assay to develop a highly sensitive, automatic WSSV detection platform targeted against ICP11 (the most highly expressed WSSV protein). After characterizing the magnetic reagents (Fe3O4 magnetic nanoparticles coated with anti ICP11), the detection limit for ICP11 protein using IMR was approximately 2 x 10(-3) ng/ml, and the linear dynamic range of the assay was 0.1~1 x 10(6) ng/ml. In assays of ICP11 protein in pleopod protein lysates from healthy and WSSV-infected shrimp, IMR signals were successfully detected from shrimp with low WSSV genome copy numbers. We concluded that this IMR assay targeting ICP11 has potential for detecting the WSSV.
The possibility of immunological memory in invertebrates is a topic that has recently attracted a lot of attention. Today, even vertebrates are known to exhibit innate immune responses that show ...memory-like properties, and since these responses are triggered by cells that are involved in the innate immune system, it seems that immune specificity and immune memory do not necessarily require the presence of B cells and T cells after all. This kind of immune response has been called “immune priming” or “trained immunity”. In this report, we review recent observations and our current understanding of immunological memory within the innate immune system in cultured shrimp and crayfish after vaccination with live vaccine, killed vaccine and subunit vaccines. We also discuss the possible mechanisms involved in this immune response.
•Invertebrates are known to exhibit innate immune responses that exhibit memory-like properties.•“Immune priming” describes the immunological memory arising from the innate immune responses after infection or vaccination.•Specific immune memory effects in shrimp and crayfish last for between 7 and 30 days.•Dscam is probably involved in trained immunity in crustaceans, but the mechanism remains elusive.
Prostate cancer has its highest incidence in the USA and is becoming a major concern in Asian countries. Bufadienolides are extracts of toxic glands from toads and are used as anticancer agents, ...mainly on leukemia cells. In the present study, the antiproliferative and apoptotic mechanisms of bufalin and cinobufagin on prostate cancer cells were investigated. Proliferation of LNCaP, DU145, and PC3 cells was measured by 3‐(4,5‐dimethylthiazol‐2‐yle)‐2,5‐diphenyltetrazolium bromide assay and the doubling time (tD) was calculated. Bufalin and cinobufagin caused changes in the tD of three prostate cancer cell lines, which were more significant than that of human mesangial cells. In addition, bufadienolides induced prostate cancer cell apoptosis more significantly than that in breast epithelial cell lines. After treatment, the caspase‐3 activity and protein expression of caspase‐3, ‐8, and ‐9 were elevated. The expression of other apoptotic modulators, including mitochondrial Bax and cytosolic cytochrome c, were also increased. However, expression of p53 was only enhanced in LNCaP cells. Downregulation of p53 by antisense TP53 restored the cell viability suppressed by bufalienolides. Furthermore, the increased expression of Fas was more significant in DU145 and PC3 cells with mutant p53 than in LNCaP cells. Transfection of Fas small interfering RNA restored cell viability in the bufadienolide‐treated cells. These results suggest that bufalin and cinobufagin suppress cell proliferation and cause apoptosis in prostate cancer cells via a sequence of apoptotic modulators, including Bax, cytochrome c, and caspases. The upstream mediators might be p53 and Fas in androgen‐dependent LNCaP cells and Fas in androgen‐independent DU145 and PC3 cells. (Cancer Sci 2008; 99: 2467–2476)
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