\u3cem\u3eVibrio parahaemolyticus\u3c/em\u3e in Rhode Island Coastal Ponds and the Estuarine Environment of Narragansett Bay

Quantification of the abundance of Vibrio parahaemolyticus in water and oysters from Rhode Island showed the presence of environmental strains and low levels of potentially pathogenic strains when water temperatures were ≥18°C, with peak levels in late July to early August. A higher abundance of the trh gene than of the tdh gene was observed

PROTEASE ACTIVITY IN THE PLASMA OF AMERICAN OYSTERS, \u3cem\u3eCRASSOSTREA VIRGINICA\u3c/em\u3e, EXPERIMENTALLY INFECTED WITH THE PROTOZOAN PARASITE \u3cem\u3ePERKINSUS MARINUS\u3c/em\u3e

Perkinsus marinus is responsible for disease and mortality of the American oyster, Crassostrea virginica. To inves-tigate the interactions between P. marinus and oyster hemocytes, protease activity was measured in plasma of oysters collected 4 hr, 24 hr, 4 days, and 2 mo after experimental infection with P. marinus. A significant increase in protease activity was observed in oyster plasma 4 hr after injection with P. marinus, followed by a sharp decrease within 24 hr. Gelatin-impregnated gel electrophoresis showed the presence of 2 major bands (60 and 112 kDa) and 3 less prevalent bands (35, 92, and 200 kDa) with metalloproteinaselike activity in the plasma of noninfected oysters. Additional bands in the 40- to 60-kDa range, corresponding to P. marinus serine proteases, were observed in oyster plasma at early time points after infection. A transient, but significant, decrease in the activity of oyster metalloproteinases was observed at early time points after infection. Coincubation of oyster plasma with P. marinus extracellular products resulted in a decrease in oyster metalloproteinases and several P. marinus proteases. This study provides insights into the role of proteases in the pathogenesis of Dermo disease

The expanded inhibitor of apoptosis gene family in oysters possesses novel domain architectures and may play diverse roles in apoptosis following immune challenge

Background: Apoptosis plays important roles in a variety of functions, including immunity and response to environmental stress. The Inhibitor of Apoptosis (IAP) gene family of apoptosis regulators is expanded in molluscs, including eastern, Crassostrea virginica, and Pacific, Crassostrea gigas, oysters. The functional importance of IAP expansion in apoptosis and immunity in oysters remains unknown. Results: Phylogenetic analysis of IAP genes in 10 molluscs identified lineage specific gene expansion in bivalve species. Greater IAP gene family expansion was observed in C. virginica than C. gigas (69 vs. 40), resulting mainly from tandem duplications. Functional domain analysis of oyster IAP proteins revealed 3 novel Baculoviral IAP Repeat (BIR) domain types and 14 domain architecture types across gene clusters, 4 of which are not present in model organisms. Phylogenetic analysis of bivalve IAPs suggests a complex history of domain loss and gain. Most IAP genes in oysters (76% of C. virginica and 82% of C. gigas), representing all domain architecture types, were expressed in response to immune challenge (Ostreid Herpesvirus OsHV-1, bacterial probionts Phaeobacter inhibens and Bacillus pumilus, several Vibrio spp., pathogenic Aliiroseovarius crassostreae, and protozoan parasite Perkinsus marinus). Patterns of IAP and apoptosis-related differential gene expression differed between the two oyster species, where C. virginica, in general, differentially expressed a unique set of IAP genes in each challenge, while C. gigas differentially expressed an overlapping set of IAP genes across challenges. Apoptosis gene expression patterns clustered mainly by resistance/susceptibility of the oyster host to immune challenge. Weighted Gene Correlation Network Analysis (WGCNA) revealed unique combinations of transcripts for 1 to 12 IAP domain architecture types, including novel types, were significantly co-expressed in response to immune challenge with transcripts in apoptosis-related pathways. Conclusions: Unprecedented diversity characterized by novel BIR domains and protein domain architectures was observed in oyster IAPs. Complex patterns of gene expression of novel and conserved IAPs in response to a variety of ecologically-relevant immune challenges, combined with evidence of direct co-expression of IAP genes with apoptosis-related transcripts, suggests IAP expansion facilitates complex and nuanced regulation of apoptosis and other immune responses in oysters

Sea Star Wasting Disease in \u3cem\u3eAsterias forbesi\u3c/em\u3e along the Atlantic Coast of North America

As keystone species, sea stars serve to maintain biodiversity and species distribution through trophic level interactions in marine ecosystems. Recently, Sea Star Wasting Disease (SSWD) has caused widespread mass mortality in several sea star species from the Pacific Coast of the United States of America (USA) and Asterias forbesi on the Atlantic Coast. A densovirus, named Sea Star associated Densovirus (SSaDV), has been associated with the wasting disease in Pacific Coast sea stars, and limited samples of A. forbesi. The goal of this research is to examine the pathogenesis of SSWD in A. forbesi on the Atlantic Coast of the USA and to determine if SSaDV is associated with the wasting disease in this species. Histological examination of A. forbesi tissues affected with SSWD showed cuticle loss, vacuolation and necrosis of epidermal cells, and oedema of the dermis, but no consistent evidence indicating the cause of the lesions. Challenge experiments by cohabitation and immersion in infected water suggest that the cause of SSWD is viral in nature, as filtration (0.22 μm) of water from tanks with sea stars exhibiting SSWD did not prevent the transmission and progression of the disease. Death of challenged sea stars occurred 7–10 d after exposure to infected water or sea stars, and the infectivity crossed species (A. forbesi and Pateria miniata) with equal penetrance. Of the 48 stars tested by quantitative real time PCR, 29 (60%) were positive for the SSaDV VP1 gene. These stars represent field-collected sea stars from all geographical regions (South Carolina to Maine) in 2012–2015, as well as stars exposed to infected stars or water from affected tanks. However, a clear association between the presence of SSaDV and SSWD signs in experimental and field-collected A. forbesi was not found in this study

Effects of chemokines on proliferation and apoptosis of human mesangial cells

BACKGROUND: Proliferation and apoptosis of mesangial cells (MC) are important mechanisms during nephrogenesis, for the maintenance of glomerular homeostasis as well as in renal disease and glomerular regeneration. Expression of chemokines and chemokine receptors by intrinsic renal cells, e.g. SLC/CCL21 on podocytes and CCR7 on MC is suggested to play a pivotal role during these processes. Therefore the effect of selected chemokines on MC proliferation and apoptosis was studied. METHODS: Proliferation assays, cell death assays including cell cycle analysis, hoechst stain and measurement of caspase-3 activity were performed. RESULTS: A dose-dependent, mesangioproliferative effect of the chemokine SLC/CCL21, which is constitutively expressed on human podocytes was seen via activation of the chemokine receptor CCR7, which is constitutively expressed on MC. In addition, in cultured MC SLC/CCL21 had a protective effect on cell survival in Fas-mediated apoptosis. The CXCR3 ligands IP-10/CXCL10 and Mig/CXCL9 revealed a proproliferative effect but did not influence apoptosis of MC. Both the CCR1 ligand RANTES/CCL5 and the amino-terminally modified RANTES analogue Met-RANTES which blocks CCR1 signalling had no effect on proliferation and apoptosis. CONCLUSIONS: The different effects of chemokines and their respective receptors on proliferation and apoptosis of MC suggest highly regulated, novel biological functions of chemokine/chemokine receptor pairs in processes involved in renal inflammation, regeneration and glomerular homeostasis

Cardiac remodeling and dysfunction in nephrotic syndrome

There is an increased incidence of heart disease in patients with chronic nephrotic syndrome (NS), which may be attributable to the malnutrition and activated inflammatory state accompanying the sustained proteinuria. In this study, we evaluated renal function, cardiac morphometry, contractile function, and myocardial gene expression in the established puromycin aminonucleoside nephrosis rat model of NS. Two weeks after aminonucleoside injection, there was massive proteinuria, decreased creatinine clearance, and a negative sodium balance. Skeletal and cardiac muscle atrophy was present and was accompanied by impaired left ventricular (LV) hemodynamic function along with decreased contractile properties of isolated LV muscle strips. The expression of selected cytokines and proteins involved in calcium handling in myocardial tissue was evaluated by real time polymerase chain reaction. This revealed that the expression of interleukin-1beta, tumor necrosis factor-alpha, and phospholamban were elevated, whereas that of cardiac sarco(endo)plasmic reticulum calcium pump protein was decreased. We suggest that protein wasting and systemic inflammatory activation during NS contribute to cardiac remodeling and dysfunction

Incorporation of soybean products in summer flounder (Paralichthys dentatus) feeds: Effects on growth and survival to bacterial challenge

As demand for fish meal as a primary protein source in aquaculture feeds has continued to increase, aquaculturists have sought a replacement with similar nutritional profile and more consistent economic value. Two feeding trials were designed to evaluate the effect of replacing fish meal with soybean meal and soy protein concentrate in summer flounder (Paralychthis dentatus) diets on fish growth and survival to challenge with the pathogenic bacterium Vibrio harveyi. Fish fed for 12. weeks with a diet in which 60% of the fish meal was replaced with a 1:1 ratio (w/. w) of soybean meal and soy protein concentrate (SBM/SPC) increased to a significantly greater mass than fish fed either a fish meal (FM) diet or a 60% replacement diet with soybean meal (SBM; p. \u3c. 0.05). Survival following bacterial challenge was significantly lower in fish fed the FM diet than fish fed the SBM or SBM/SPC diets (p \u3c 0.05). In the second feeding trial, 60% of the fish meal was replaced in six diets by either soybean meal, soy protein concentrate, or varying ratios of the two. The highest body weights at the end of the trial were observed in the fish fed the FM and 60% SPC replacement diets compared to the other groups (p. \u3c. 0.05). Fish fed a 12% SBM/48% SPC replacement diet had the highest survival to bacterial challenge, significantly higher (p ≤ 0.001) than fish in other groups except the fish fed the 24% SBM/36% SPC diet. Fish fed 40% SBM/20% SPC and 60% SPC showed the lowest survival to bacterial challenge. These results show that: 1) growth of summer flounder fed a diet in which 60% of the fish meal was replaced with soy protein concentrate was similar to the growth seen in fish fed fish meal diets; 2) addition of increasing amounts of soybean meal in the replacement diet led to a decrease in growth compared to diets with fish meal. However, replacement of 60% of the fish meal with a mix of soybean meal and soy protein concentrate containing 12 or 24% of soybean meal led to increased survival of fish to bacterial challenge. Further identification of the products in soybean meal leading to increased survival of summer flounder could lead to the development of replacement diets for summer flounder that provide increased survival to disease challenge without compromising growth. Statement of relevance: Sustainable plant-based diets promoting disease resistance