Impacts of Poultry House Environment on Poultry Litter Bacterial Community Composition

Viral and bacterial pathogens are a significant economic concern to the US broiler industry and the ecological epicenter for poultry pathogens is the mixture of bedding material, chicken excrement and feathers that comprises the litter of a poultry house. This study used high-throughput sequencing to assess the richness and diversity of poultry litter bacterial communities, and to look for connections between these communities and the environmental characteristics of a poultry house including its history of gangrenous dermatitis (GD). Cluster analysis of 16S rRNA gene sequences revealed differences in the distribution of bacterial phylotypes between Wet and Dry litter samples and between houses. Wet litter contained greater diversity with 90% of total bacterial abundance occurring within the top 214 OTU clusters. In contrast, only 50 clusters accounted for 90% of Dry litter bacterial abundance. The sixth largest OTU cluster across all samples classified as an Arcobacter sp., an emerging human pathogen, occurring in only the Wet litter samples of a house with a modern evaporative cooling system. Ironically, the primary pathogenic clostridial and staphylococcal species associated with GD were not found in any house; however, there were thirteen 16S rRNA gene phylotypes of mostly Gram-positive phyla that were unique to GD-affected houses and primarily occurred in Wet litter samples. Overall, the poultry house environment appeared to substantially impact the composition of litter bacterial communities and may play a key role in the emergence of food-borne pathogens

Variation in the CTLA4/CD28 gene region confers an increased risk of coeliac disease.

Susceptibility to coeliac disease involves HLA and non-HLA-linked genes. The CTLA4/CD28 gene region encodes immune regulatory T-cell surface molecules and is a strong candidate as a susceptibility locus. We evaluated CTLA4/CD28 in coeliac disease by genetic linkage and association and combined our findings with published studies through a meta-analysis. 116 multiplex families were genotyped across CTLA4/CD28 using eight markers. The contribution of CTLA4/CD28 to coeliac disease was assessed by non-parametric linkage and association analyses. Seven studies were identified that had evaluated the relationship between CTLA4/CD28 and coeliac disease and a pooled analysis of data undertaken. In our study there was evidence for a relationship between variation in the CTLA4/CD28 region and coeliac disease by linkage and association analyses. However, the findings did not attain formal statistical significance (p = 0.004 and 0.039, respectively). Pooling findings with published results showed significant evidence for linkage (504 families) and association (940 families): p values, 0.0001 and 0.0014 at D2S2214, respectively, and 0.0008 and 0.0006 at D2S116, respectively. These findings suggest that variation in the CD28/CTLA4 gene region is a determinant of coeliac disease susceptibility. Dissecting the sequence variation underlying this relationship will depend on further analyses utilising denser sets of markers

In vitro techniques for assessing neurotoxicity using human IPSC-derived neuronal models

The central nervous system consists of a multitude of different neurons and supporting cells that form networks for transmitting neuronal signals. Proper function of the nervous system depends critically on a wide range of highly regulated processes including intracellular calcium homeostasis, neurotransmitter release, and electrical activity. Due to the diversity of cell types and complexity of signaling processes, the (central) nervous system is very vulnerable to toxic insults. Nowadays, a broad range of approaches and cell models is available to study neurotoxicity. In this chapter we show the applicability of human induced pluripotent stem cell (hiPSC)-derived neuronal co-cultures for in vitro neurotoxicity testing. We demonstrate that immunocytochemistry can be used to visualize networks of cultured cells and to differentiate between different cell types. Live cell imaging and electrophysiology techniques demonstrate that the neuronal networks develop spontaneous activity, including synchronized calcium oscillations that coincide with spontaneous changes in membrane potential as well as spontaneous electrical activity with defined (network) bursting. Importantly, as shown in this chapter, spontaneously active human iPSC-derived neuronal co-cultures are suitable for in vitro neurotoxicity assessment. Future application of live imaging and electrophysiological techniques on hiPSC from different donors and/or patients differentiated in different cell types holds great promise for personalized neurotoxicity assessment and safety screening