A protein kinase-major sperm protein gene hijacked by a necrotrophic fungal pathogen triggers disease susceptibility in wheat.

Septoria nodorum blotch (SNB), a disease caused by the necrotrophic fungal pathogen Parastagonospora nodorum, is a threat to wheat (Triticum aestivum) production worldwide. Multiple inverse gene-for-gene interactions involving the recognition of necrotrophic effectors (NEs) by wheat sensitivity genes play major roles in causing SNB. One interaction involves the wheat gene Snn3 and the P. nodorum NE SnTox3. Here, we used a map-based strategy to clone the Snn3-D1 gene from Aegilops tauschii, the D-genome progenitor of common wheat. Snn3-D1 contained protein kinase and major sperm protein domains, both of which were essential for function as confirmed by mutagenesis. As opposed to other characterized interactions in this pathosystem, a compatible Snn3-D1-SnTox3 interaction was light-independent, and Snn3-D1 transcriptional expression was downregulated by light and upregulated by darkness. Snn3-D1 likely emerged in Ae. tauschii due to an approximately 218-kb insertion that occurred along the west bank of the Caspian Sea. The identification of this new class of NE sensitivity genes combined with the previously cloned sensitivity genes demonstrates that P. nodorum can take advantage of diverse host targets to trigger SNB susceptibility in wheat.

Spatial and temporal axes impact ecology of the gut microbiome in juvenile European lobster (Homarus gammarus).

Microbial communities within the gut can markedly impact host health and fitness. To what extent environmental influences affect the differential distribution of these microbial populations may therefore significantly impact the successful farming of the host. Using a sea-based container culture (SBCC) system for the on-growing of European lobster (Homarus gammarus), we tracked the bacterial gut microbiota over a 1-year period. We compared these communities with lobsters of the same cohort, retained in a land-based culture (LBC) system to assess the effects of the culture environment on gut bacterial assemblage and describe the phylogenetic structure of the microbiota to compare deterministic and stochastic assembly across both environments. Bacterial gut communities from SBCCs were generally more phylogenetically clustered, and therefore deterministically assembled, compared to those reared in land-based systems. Lobsters in SBCCs displayed significantly more species-rich and species-diverse gut microbiota compared to those retained in LBC. A reduction in the bacterial diversity of the gut was also associated with higher infection prevalence of the enteric viral pathogen Homarus gammarus nudivirus (HgNV). SBCCs may therefore benefit the overall health of the host by promoting the assembly of a more diverse gut bacterial community and reducing the susceptibility to disease.

Development and optimization of a cell-associated challenge model for Mycoplasma hyorhinis in 7-week-old cesarean-derived, colostrum-deprived pigs.

Mycoplasma hyorhinis (MHR) causes polyserositis and lameness in grower pigs. While herd-specific vaccines for this bacterium are being marketed, there are currently no licensed, commercially available vaccines for MHR. The objective of this study was to develop a challenge model in cesarean-derived, colostrum-deprived (CDCD) pigs using cell-associated MHR that results in both severe pericarditis and lameness, in order to evaluate suitable vaccine candidates. We investigated administering MHR to 7-week-old pigs over 3 d using 3 different routes compared to administering MHR on a single day using 1 of 3 routes. Pigs were monitored for 21 d for signs of lameness and well-being. At the end of the study, pigs were examined for evidence of polyserositis and arthritis associated with Mycoplasma. Results indicate that clinical manifestation of disease depended more on the route of administration than on the total dose given. A single intravenous (IV) administration of MHR resulted in extensive polyserositis, while a single intranasal (IN) administration showed little to no signs of disease. A single intraperitoneal (IP) administration did not induce the same level of polyserositis as observed in the IV group, but did result in an increased incidence of lameness. Furthermore, pigs administered MHR by IP (Day 0), IV (Day 1), and IN (Day 2) on 3 consecutive days showed a more robust disease manifestation, which resulted in both polyserositis and lameness. Optimization of this group showed that elimination of the 3rd-day IN challenge had no detrimental effect on clinical outcomes. The consecutive day administration of cell-associated MHR will allow polyserositis and lameness to be simultaneously evaluated in future vaccine trials.

Mycoplasma hyorhinis (MHR) cause une polysérosite et de la boiterie chez les porcs en croissance. Alors que pour ce microorganisme des vaccins spécifiques de troupeaux sont disponibles, il n'y a actuellement aucun vaccin homologué commercialement disponible pour MHR. L'objectif de la présente étude était de développer un modèle d'infection chez des porcs obtenus par césarienne et privés de colostrum en utilisant du MHR associé à des cellules qui causait une péricardite sévère et de la boiterie, afin d'évaluer des vaccins candidats appropriés. Nous avons évalué l'administration de MHR à des porcs âgés de 7 semaines sur 3 jours en utilisant trois voies d'administration différentes comparativement à l'administration de MHR en une seule journée en utilisant une des trois routes. Les porcs ont été suivis pendant 21 jours pour des signes de boiterie et de bien-être. À la fin de l'étude, les porcs ont été examinés pour des évidences de polysérosite et d'arthrite associées avec Mycoplasma. Les résultats indiquaient que la manifestation clinique de la maladie était plus dépendante de la voie d'administration que du nombre total de doses administré. L'administration intraveineuse (IV) d'une dose unique de MHR a résulté en une polysérosite généralisée, alors qu'une dose unique par voie intranasale (IN) ne causa que peu ou pas de signes de maladie. L'administration d'une dose unique par voie intrapéritonéale (IP) n'a pas induit le même degré de polysérosite que celui observé dans le groupe IV, mais on nota une augmentation de l'incidence de boiterie. De plus, les porcs auxquels on administra MHR par voie IP (Jour 0), IV (Jour 1), et IN (Jour 2) pendant 3 jours consécutifs ont montré des manifestations plus fortes de la maladie, ce qui résultat en polysérosite et boiterie. L'optimisation pour ce groupe a démontré que l'élimination de l'inoculation IN au troisième jour n'avait aucun effet délétère sur les résultats cliniques. L'administration de MHR associé à des cellules pendant des jours consécutifs permettra d'évaluer simultanément la polysérosite et la boiterie lors d'essais futurs de vaccins.(Traduit par Docteur Serge Messier).

Age susceptibility of caesarian derived colostrum deprived pigs to Mycoplasma hyorhinis challenge.

Mycoplasma hyorhinis (MHR) is a major cause of lameness, arthritis, and polyserositis among growing pigs. Reduced performance and culling due to MHR infection result in economic losses in swine production. We have previously developed an MHR challenge model in seven week-old CDCD pigs using cell-associated challenge material which results in both severe pericarditis and lameness. In this study we sequentially challenged CDCD pigs at seven, ten, thirteen, and sixteen weeks of age. Lameness was observed in >60% of the animals in the first three age groups but only 33% in the oldest age group. The number of animals with arthritis declined from 100% at seven weeks, to 56% at ten weeks and approximately 25% at both thirteen and sixteen weeks of age. Pericarditis was observed in 87% of the seven week challenge group, 28% in the ten week challenge group, 8% in the thirteen week challenge group and 4% in the sixteen week challenge group. All challenged groups showed a reduced average daily gain (ADG) compared to their age-matched non-challenged control groups. The largest disparity in ADG (1.2 lbs/day difference) was noted at thirteen weeks of age. Results of this study demonstrate that these animals were susceptible to MHR-associated lameness through sixteen weeks of age while susceptibility to MHR-associated polyserositis appeared to peak at seven weeks of age.

Fecal microbiota manipulation prevents dysbiosis and alcohol-induced liver injury in mice.

BACKGROUND & AIMS: Alcoholic liver disease (ALD) is a leading cause of liver failure and mortality. In humans, severe alcoholic hepatitis is associated with key changes to intestinal microbiota (IM), which influences individual sensitivity to develop advanced ALD. We used the different susceptibility to ALD observed in two distinct animal facilities to test the efficiency of two complementary strategies (fecal microbiota transplantation and prebiotic treatment) to reverse dysbiosis and prevent ALD. METHODS: Mice were fed alcohol in two distinct animal facilities with a Lieber DeCarli diet. Fecal microbiota transplantation was performed with fresh feces from alcohol-resistant donor mice to alcohol-sensitive receiver mice three times a week. Another group of mice received pectin during the entire alcohol consumption period. RESULTS: Ethanol induced steatosis and liver inflammation, which were associated with disruption of gut homeostasis, in alcohol-sensitive, but not alcohol resistant mice. IM analysis showed that the proportion of Bacteroides was specifically lower in alcohol-sensitive mice (p<0.05). Principal coordinate analysis showed that the IM of sensitive and resistant mice clustered differently. We targeted IM using two different strategies to prevent alcohol-induced liver lesions: (1) pectin treatment which induced major modifications of the IM, (2) fecal microbiota transplantation which resulted in an IM very close to that of resistant donor mice in the sensitive recipient mice. Both methods prevented steatosis, liver inflammation, and restored gut homeostasis. CONCLUSIONS: Manipulation of IM can prevent alcohol-induced liver injury. The IM should be considered as a new therapeutic target in ALD. LAY SUMMARY: Sensitivity to alcoholic liver disease (ALD) is driven by intestinal microbiota in alcohol fed mice. Treatment of mice with alcohol-induced liver lesions by fecal transplant from alcohol fed mice resistant to ALD or with prebiotic (pectin) prevents ALD. These findings open new possibilities for treatment of human ALD through intestinal microbiota manipulation.

Effect of guava leaves on the growth performance and cytokine gene expression of Labeo rohita and its susceptibility to Aeromonas hydrophila infection.

The present study aimed to evaluate the effects of Psidium guajava L. (guava) leaves on the growth and immune response of the fish species Labeo rohita and its susceptibility to Aeromonas hydrophila infection. Diets containing five different concentrations of guava leaves (0% [basal diet], 0.1% [G1], 0.5% [G2], 1% [G3], and 1.5% [G4]) were fed to fish (average weight: 11.1 g) for 60 days. Various growth and immune parameters were examined 60 days post-feeding. Fish were challenged with A. hydrophila at the end of the trial, and mortalities were recorded over 15 days post-infection. We found that growth parameters such as percent weight gain (657.61 ± 9.74) and specific growth rate (3.37 ± 0.021) were significantly higher in G2 group than in the control (P < 0.05). Among the immune parameters examined, lysozyme levels (79.5 ± 5.1 U mL(-1)), leukocyte phagocytic activity (52 ± 4.3%), and alternative complement pathway activity (ACP) (186.1 ± 8.3 U mL(-1)) were significantly high (P < 0.05) in G2 fed group; there was, however, no significant effect of guava leaves at any concentration on plasma IgM level. Of the cytokine-related genes examined, interleukin-1beta (IL-1ß) and tumour necrosis factor-alpha (TNF-α) were up-regulated in the head-kidney, intestine, and hepatopancreas of fish fed experimental diets, and expression was significantly higher in G2 and G3 than in the control group. In contrast, gene expression of IL-10, transforming growth factor-beta (TGF-ß), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and transcription factor nuclear factor-κB (NF-κB) were down-regulated in the treatment groups. Moreover, fish fed the G2 diet exhibited a significantly higher post-challenge survival rate (66.66%). Collectively, these results suggest that dietary supplementation with guava leaves (at 0.5% concentration) could promote growth performance and strengthen immunity of L. rohita. Guava leaves therefore represent a promising feed additive for carps in aquaculture.

Effects of a phytogenic feed additive on growth performance, susceptibility of channel catfish to Edwardsiella ictaluri and levels of mannose binding lectin.

A study was conducted to investigate the effect of a phytogenic feed additive (Digestarom® P.E.P. MGE; containing the essential oils carvacrol, thymol, anethol, and limonene) on growth performance and disease susceptibility to Edwardsiella ictaluri. Two hundred and fifty juvenile channel catfish, Ictalurus punctatus (7.2 ± 0.1 g) were allotted into the following treatments: Control (floating diet) and EO (floating diet supplemented with essential oils). The fish were fed their respective diets for 6 weeks. At the end of the study, all fish were exposed to virulent E. ictaluri by bath immersion (1.9 × 10(7) cfu/mL; final concentration). Plasma and tissue samples were taken to quantify protein and mRNA expression levels of mannose binding lectin (MBL). Weight gain and food conversion ratio were similar between treatments. After exposing fish to virulent E. ictaluri and monitoring mortality for 21 days, survival was 43% higher (69.5 vs 48.4%) in fish fed EO compared to fish not treated with EO (P < 0.05). One day after challenge, plasma MBL levels were down-regulated in the non-treated fish compared to non-challenged fish. In the EO fish, MBL levels were similar to non-challenged fish but significantly higher than non-treated fed fish (P < 0.001). By d 7, plasma MBL levels increased in non-treated fed fish to levels observed in the EO and non-challenged fish. On d 14, MBL mRNA levels were upregulated 15-fold in fish fed EO compared to non-treated fed fish and non-challenged fish (P < 0.001). The results demonstrate that essential oils improved survival of channel catfish challenged with E. ictaluri. Mechanisms through which essential oils improve survival may involve MBL.

Dietary sodium selenite affects host intestinal and systemic immune response and disease susceptibility to necrotic enteritis in commercial broilers.

1. This study was to evaluate the effects of supplementary dietary selenium (Se) given as sodium selenite on host immune response against necrotic enteritis (NE) in commercial broiler chickens. 2. Chicks were fed from hatching on a non-supplemented diet or diets supplemented with different levels of Se (0.25, 0.50, and 1.00 Se mg/kg). To induce NE, broiler chickens were orally infected with Eimeria maxima at 14 d of age and then with Clostridium perfringens 4 d later using our previously established NE disease model. 3. NE-associated clinical signs and host protective immunity were determined by body weight changes, intestinal lesion scores, and serum antibodies against α-toxin and necrotic enteritis B (NetB) toxin. The effects of dietary Se on the gene expression of pro-inflammatory cytokines e.g., interleukin (IL)-1ß, IL-6, IL-8LITAF (lipopolysaccharide-induced TNFα-factor), tumour necrosis factor (TNF) SF15, and inducible nitric oxide synthase (iNOS), glutathione peroxidase 7 (GPx7), and avian ß-defensins (AvBD) 6, 8, and 13 (following NE infection) were analysed in the intestine and spleen. 4. The results showed that dietary supplementation of newly hatched broiler chicks with 0.25 Se mg/kg from hatch significantly reduced NE-induced gut lesions compared with infected birds given a non-supplemented diet. The levels of serum antibody against the NetB toxin in the chicks fed with 0.25 and 0.50 mg/kg Se were significantly higher than the non-supplemented control group. The transcripts for IL-1ß, IL-6, IL-8, iNOS, LITAF, and GPx7, as well as AvBD6, 8, and 13 were increased in the intestine and spleen of Se-supplemented groups, whereas transcript for TNFSF15 was decreased in the intestine. 5. It was concluded that dietary supplementation with optimum levels of Se exerted beneficial effects on host immune response to NE and reduced negative consequence of NE-induced immunopathology.

Expression of the maize ZmGF14-6 gene in rice confers tolerance to drought stress while enhancing susceptibility to pathogen infection.

14-3-3 proteins are found in all eukaryotes where they act as regulators of diverse signalling pathways associated with a wide range of biological processes. In this study the functional characterization of the ZmGF14-6 gene encoding a maize 14-3-3 protein is reported. Gene expression analyses indicated that ZmGF14-6 is up-regulated by fungal infection and salt treatment in maize plants, whereas its expression is down-regulated by drought stress. It is reported that rice plants constitutively expressing ZmGF14-6 displayed enhanced tolerance to drought stress which was accompanied by a stronger induction of drought-associated rice genes. However, rice plants expressing ZmGF14-6 either in a constitutive or under a pathogen-inducible regime showed a higher susceptibility to infection by the fungal pathogens Fusarium verticillioides and Magnaporthe oryzae. Under infection conditions, a lower intensity in the expression of defence-related genes occurred in ZmGF14-6 rice plants. These findings support that ZmGF14-6 positively regulates drought tolerance in transgenic rice while negatively modulating the plant defence response to pathogen infection. Transient expression assays of fluorescently labelled ZmGF14-6 protein in onion epidermal cells revealed a widespread distribution of ZmGF14-6 in the cytoplasm and nucleus. Additionally, colocalization experiments of fluorescently labelled ZmGF14-6 with organelle markers, in combination with cell labelling with the endocytic tracer FM4-64, revealed a subcellular localization of ZmGF14-6 in the early endosomes. Taken together, these results improve our understanding of the role of ZmGF14-6 in stress signalling pathways, while indicating that ZmGF14-6 inversely regulates the plant response to biotic and abiotic stresses.

A role for inositol hexakisphosphate in the maintenance of basal resistance to plant pathogens.

Phytic acid (myo-inositol hexakisphosphate, InsP6) is an important phosphate store and signal molecule in plants. However, low-phytate plants are being developed to minimize the negative health effects of dietary InsP6 and pollution caused by undigested InsP6 in animal waste. InsP6 levels were diminished in transgenic potato plants constitutively expressing an antisense gene sequence for myo-inositol 3-phosphate synthase (IPS, catalysing the first step in InsP6 biosynthesis) or Escherichia coli polyphosphate kinase. These plants were less resistant to the avirulent pathogen potato virus Y and the virulent pathogen tobacco mosaic virus (TMV). In Arabidopsis thaliana, mutation of the gene for the enzyme catalysing the final step of InsP6 biosynthesis (InsP5 2-kinase) also diminished InsP6 levels and enhanced susceptibility to TMV and to virulent and avirulent strains of the bacterial pathogen Pseudomonas syringae. Arabidopsis thaliana has three IPS genes (AtIPS1-3). Mutant atips2 plants were depleted in InsP6 and were hypersusceptible to TMV, turnip mosaic virus, cucumber mosaic virus and cauliflower mosaic virus as well as to the fungus Botrytis cinerea and to P. syringae. Mutant atips2 and atipk1 plants were as hypersusceptible to infection as plants unable to accumulate salicylic acid (SA) but their increased susceptibility was not due to reduced levels of SA. In contrast, mutant atips1 plants, which were also depleted in InsP6, were not compromised in resistance to pathogens, suggesting that a specific pool of InsP6 regulates defence against phytopathogens.

Susceptibility to pristane-induced arthritis is altered with changes in bowel flora.

Pristane-induced arthritis (PIA) is unique among the animal arthritides in that a non-infectious, non-antigenic oil induces a chronic immune based arthritis with a prolonged delay between exposure to the inciting agent and development of the disease. Mice with pristane-induced arthritis have elevated T cell and humoral responses to the 65 kDa heat shock protein derived from Mycobacterium bovis (hsp65) and in common with several other models of autoimmune diseases the incidence of PIA is markedly suppressed by preimmunisation with hsp65 in Freund's incomplete adjuvant (Thompson et al. (1990) Eur. J. Immunol. 20, 2479). Recent studies have investigated how autoimmune reactions to heat shock proteins are involved in the development of arthritis. Arthritic CBA/Igb mice given pristane alone develop antibodies to both hsp65 and GroEl (bacterial 60 kDa heat shock proteins) and to hsp58 (the mammalian equivalent). Moreover, the splenic T cells of such mice proliferate vigorously in response to both bacterial and mammalian 60 kDa heat shock proteins. Remarkably, the anti-hsp65 antibody response in normal mice rises rapidly with age, directly correlating with the age related incidence of PIA. In addition, specific pathogen free mice (SPF) maintained in an isolator have negligible anti-hsp65 responses but these convert to positive responses if the animals are exposed to the open part of the animal facility (Thompson et al. (1992) Arthritis Rheum. 35, 139).(ABSTRACT TRUNCATED AT 250 WORDS)