Inoculative release strategies of Macrolophus pygmaeus Rambur (Hemiptera: Miridae) in tomato crops: population dynamics and dispersal

Journal of Plant Diseases and Protection - Macrolophus pygmaeus Rambur (Hemiptera: Miridae) is a key biological control agent in greenhouse tomato crops. In the present study, we describe the...     

Antibody isotype profiles in serum and circulating antibody-secreting cells following mucosal and peripheral immunisations of sheep

The isotype-specific antibody responses of sheep immunised with keyhole limpet hemocyanin by a peripheral route (intramuscular (i.m.) injection) were compared to those induced by immunisation via different mucosal routes: (1) intra-nasal spray; (2) rectal deposition with cholera toxin; (3) injection into the mucosa of the small intestine or rectum. Antigen-specific IgG1 antibodies were induced in the i.m., intra-intestinal and intra-rectal injection groups and in a proportion of the cholera toxin immunised sheep, but not in the intra-nasal immunisation group. IgA was the only antibody isotype detected in serum collected from the intra-nasal immunisation group. No significant differences in serum IgA levels were detected in any of the mucosal immunisation groups as compared to the i.m. injection group. In contrast, analysis of the in vitro antibody profiles secreted by circulating antibody-secreting cells (ASC) revealed significantly higher IgA responses in the supernatants from all mucosal immunisation groups. This suggests that the measurement of antibodies secreted by circulating ASCs may be a better correlate of local mucosal responses in ruminants, as has been previously demonstrated in human studies. In addition to IgG1 and IgA responses, immunisation by direct injection of antigen formulations into the intestinal and rectal mucosa were the only groups to induce consistently high IgG2 antibodies in serum and ASC cultures.     

Novel Alkaloids from Marine Actinobacteria: Discovery and Characterization

The marine environment is an excellent resource for natural products with therapeutic potential. Its microbial inhabitants, often associated with other marine organisms, are specialized in the synthesis of bioactive secondary metabolites. Similar to their terrestrial counterparts, marine Actinobacteria are a prevalent source of these natural products. Here, we discuss 77 newly discovered alkaloids produced by such marine Actinobacteria between 2017 and mid-2021, as well as the strategies employed in their elucidation. While 12 different classes of alkaloids were unraveled, indoles, diketopiperazines, glutarimides, indolizidines, and pyrroles were most dominant. Discoveries were mainly based on experimental approaches where microbial extracts were analyzed in relation to novel compounds. Although such experimental procedures have proven useful in the past, the methodologies need adaptations to limit the chance of compound rediscovery. On the other hand, genome mining provides a different angle for natural product discovery. While the technology is still relatively young compared to experimental screening, significant improvement has been made in recent years. Together with synthetic biology tools, both genome mining and extract screening provide excellent opportunities for continued drug discovery from marine Actinobacteria.     

The effect of immunosuppression with cyclosporin A on the development of sheep scab

The present study confirms that following infection with the ectoparasitic sheep scab mite, Psoroptes ovis, there is a rapid (within 24 h) inflammatory influx of eosinophils and apoptosis of the keratinocytes at the site of infection. In order to investigate whether these inflammatory reactions are important in the maintenance of mite infection, a group of animals were treated daily after the establishment of infection with the potent anti-inflammatory drug, Cyclosporin A. The course of infection was monitored by determining the lesion area and mite numbers, systemic antibody and blood eosinophils, as well as the inflammatory cells and T cell sub-populations within the lesion throughout the 6-week duration of the experiment. These parameters were compared with those in a similar infected control (non-treated) group. In control infected animals, the lesion area and mite numbers increased steadily throughout the 6-week period. In contrast, lesion area and mite numbers were severely depressed in the group which received Cyclosporin A. Local and systemic eosinophils, and systemic antibody were also significantly reduced in the drug treated animals, compared to controls. Surprisingly however, the number of lesional pan T cells, T helper cells, gammadeltaT cells and dendritic cells in Cyclosporin A treated animals were either the same, or significantly (P < 0.05) enhanced when compared to the control infected animals at the termination of the experiment. The results will be discussed in terms of the role of the dermal inflammatory response in the establishment and maintenance of the sheep scab mite.     

Galectin secretion and binding to adult Fasciola hepatica during chronic liver fluke infection of sheep

Galectins are increasingly recognised as important mediators of immune homeostasis and disease regulation, but comparatively little is known about their role in parasite infection. This study investigates the interaction between two ovine galectins, galectin-11 and galectin-14, and the parasitic liver fluke, F. hepatica. Galectin-14 was found in eosinophils infiltrating the tissue surrounding infected bile ducts and secreted in the connective tissue, while galectin-11 was specifically induced in epithelial cells of bile ducts from infected sheep. Strong nuclear staining was observed for galectin-11. Both galectins were found to be secreted into the bile fluid of parasite infected sheep, and were also detected in the excretory/secretory products of adult flukes, following their removal from the ovine host. Recombinant galectin-14, but not recombinant galectin-11, was found to bind specifically to the surface tegument of adult flukes in a carbohydrate dependent manner. This study shows for the first time that both galectin-14 and galectin-11 are produced in liver tissue after chronic liver fluke infection and that they can directly interact with the parasite in the bile ducts. Galectin-11 may also be involved in epithelial cell turnover and cancerogenesis.     

Vegetation-type effects on performance and meat quality of growing Engadine and Valaisian Black Nose sheep grazing alpine pastures

Lambs of two Swiss mountain breeds, Engadine Sheep (ES; n=55) and Valaisian Black Nose Sheep (VS; n=55), were fattened in 2010 and 2011 on one lowland and three alpine pastures. Groups of six to seven lambs per breed were allocated to pastures of a size allowing ad libitum intake on the following four vegetation types: (i) species-poor and nutrient-rich lowland (400 m a.s.l.) ryegrass–clover ley on flat terrain (‘lowland-rich’); (ii) alpine, species-rich and nutrient-rich vegetation type on a flat terrain (1950 m; ‘alpine-rich’); (iii) alpine, species-rich vegetation type, moderate in nutrients on steep terrain (2150 m; ‘alpine-moderate’); and (iv) alpine, species-rich and nutrient-poor vegetation type on steep terrain (2150 m; ‘alpine-poor’). Lambs were slaughtered after 9 weeks of grazing in a commercial slaughterhouse. Carcasses were subjected to the Swiss CH-TAX classification grid. Meat quality was analysed on the Musculus longissimus dorsi (LD) in the segment of Musculus longissimus lumborum. Forage quality varied among vegetation types as anticipated. Across all sites, ES were superior (P<0.001) to VS in dressing percentage (43.9 vs. 38.4), carcass weight (18.4 vs. 16.4 kg), meat conformation and fat cover scores, even though daily gains had been lower (105 vs. 122 g/d; P<0.05). Meat of ES contained more dry matter, protein, total ash (P<0.001) and fat (P<0.05). Their meat was darker and more intensive red, had lower cooking losses (23.0 vs. 25.1%) but was less tender (65.6 vs. 58.1 N) compared to VS (P<0.001). Vegetation types offering good quality forage (lowland-rich and alpine-rich) enhanced average daily gains, dressing percentage, meat conformation and fat cover scores (mostly P<0.05 against alpine-moderate and -poor). Similarly, a higher vegetation quality promoted a higher intramuscular fat and lower cooking losses. Meat from lowland-rich was darkest and had the lowest shear force (P<0.05). Almost no breed×site interactions occurred in growth performance as well as carcass and meat quality. It was therefore concluded that both breeds are similarly well adapted to the extensive pasture production system in alpine regions. Still, ES seem to be the more efficient one of the two sheep breeds. The results also indicate that growth performance and meat quality clearly vary between vegetation types in animals grazing alpine pastures.     

Studies on neonatal calf diarrhoea caused by rotavirus: transmission of the disease and attempted vaccination of colostrum-deprived calves

Mild to severe scouring could be produced in colostrum-deprived calves with tissue culture-adapted rotavirus and feacal material from field cases of calf diarrhoea. The feaces of experimentally infected calves contained rotavirus for at least 3 days. Pathogenic bacteria were presented in one calf only and this calf also showed the most severe gastroenteritis. Eight calves were vaccinated with a live rotaviral calf diarrhoea vaccine and subsequently challenged with infective rotavirus. Mild scouring was observed after vaccination, but the calves remained normal after challenge. Rotavirus particles were detectable in the faeces for a few days after vaccination and challenge.     

Transmission of methicillin resistant Staphylococcus aureus among pigs during transportation from farm to abattoir

The prevalence of methicillin resistant Staphylococcus aureus (MRSA) in pigs at abattoirs is higher than in pigs sampled on farms. This study investigated whether MRSA negative pigs can become MRSA positive during transportation from the farm to the abattoir after exposure to other pigs and environmental sources of MRSA. Nasal swabs were collected from four batches of pigs during loading at the farm, on arrival at the abattoir and after stunning. Environmental wipes were taken from lorries after transporting pigs and from lairages after holding pigs. All pigs (n = 117) tested MRSA negative before transportation. On arrival at the abattoir, 12/117 (10.3%) pigs in two batches tested MRSA positive. In lorries that tested positive after transportation, the prevalence of MRSA positive pigs was 21.1%, whereas no MRSA was detected in pigs that had been transported in lorries that tested negative after transportation. At stunning, all batches and 70/117 (59.8%) pigs tested MRSA positive. Pigs can become MRSA positive in the short period of time during transportation from the farm to stunning at the abattoir.     

Genotypic characterisation and cluster analysis of Campylobacter jejuni isolates from domestic pets, human clinical cases and retail food

The genetic similarity of Campylobacter jejuni isolates from pets, compared to human clinical cases and retail food isolates collected in Ireland over 2001-2006 was investigated by cluster analysis of pulsed-field gel electrophoresis (PFGE) fingerprinting profiles. Comparison of the PFGE profiles of 60 pet isolates and 109 human isolates revealed that seven (4.1%) profiles were grouped in clusters including at least one human and one pet C. jejuni isolate. In total six (1.6%) of 60 pet and 310 food profiles were in clusters with at least one food and one pet C. jejuni isolate. The detection of only a small number of genetically indistinguishable isolates by PFGE profile cluster analysis from pets and from humans with enteritis in this study suggests that pets are unlikely to be an important reservoir for human campylobacteriosis in Ireland. However, genetically indistinguishable isolates were detected and C. jejuni from pets may circulate and may contribute to clinical infections in humans. In addition, contaminated food fed to pets may be a potential source of Campylobacter infection in pets, which may subsequently pose a risk to humans.