To determine if one passage of Salmonella enterica serovar Typhimurium in the presence of farm disinfectants selected for mutants with decreased susceptibility to disinfectants and/or antibiotics. Eight Salmonella Typhimurium strains including field isolates and laboratory mutants were exposed to either a tar oil phenol (PFD) disinfectant, an oxidizing compound disinfectant (OXC), an aldehyde based disinfectant (ABD) or a dairy sterilizer disinfectant (based on quaternary ammonium biocide) in agar. The susceptibility of mutants obtained after disinfectant exposure to antibiotics and disinfectants was determined as was the accumulation of norfloxacin. The proteome of SL1344 after exposure to PFD and OXC was analysed using two-dimensional liquid chromatography mass spectrometry. Strains with either acrB or tolC inactivated were more susceptible to most disinfectants than other strains. The majority (3/5) of mutants recovered after disinfectant exposure required statistically significantly longer exposure times to disinfectants than their parent strains to generate a 5 log kill. Small decreases in antibiotic susceptibility were observed but no mutants were multiply antibiotic-resistant (MAR). Notably exposure to ABD decreased susceptibility to ciprofloxacin in some strains. Mutants with increased disinfectant tolerance were able to survive and persist in chicks as well as in parent strains. Analysis of proteomes revealed significantly increased expression of the AcrAB–TolC efflux system after PFD exposure. Data presented demonstrate that efflux pumps are required for intrinsic resistance to some disinfectants and that exposure to disinfectants can induce expression of the AcrAB–TolC efflux system, but that single exposure was insufficient to select for MAR strains.

With increasing global demand for animal protein, it is very important to investigate the impact of the bovine rumen microbiome on its functional traits. In order to acquire accurate and reproducible data for this type of study, it is important to understand what factors can affect the results of microbial community analysis, and where biases can occur. This study shows the impact of different DNA extraction methods on microbial community composition. Five DNA extraction methods were used on a ruminal sample. These experiments expose a high level of variability between extraction methods in relation to the microbial communities observed. As direct access to the rumen is required, we also investigated possible alternative sampling sites that could be utilised as non-invasive indicators of the bovine rumen microbiome. Therefore, oral swabs and faecal samples were taken in addition to ruminal samples, and DNA was extracted using a single method, reducing bias, and analysed. This is a small pilot study intending to reinforce the need for a universally used methodology for rumen microbiome analysis. Although alternative sampling points can indicate some of the communities present in the rumen, this must be approached cautiously, as there are limits to the depth of community analysis possible without direct rumen sampling.

STED microscopy uncovers a delicate balance of stability and volatility of stable spines in mouse cortex over 1 month.

An increasing number of fishmeal supplements are becoming the focus of aquaculture research, with a special emphasis on microalgae/cyanobacteria such as spirulina being considered as sustainable alternatives. New feed ingredients can have a far-reaching impact on the intestinal microbiome and therefore play an important role in the development and the health of fish. However, the influence of these alternatives on the microbiome is largely unknown. We undertook a 10 weeks feeding experiment on 120 African catfish with an initial body weight of 50.1 ± 2.95 g. To understand the effect of the spirulina supplementation, two isoenergetic experimental diets were formulated, containing either fishmeal or spirulina as a protein source. The 16S rRNA sequencing was used to analyze the intestinal bacteria microbiota. Results show that the observed richness indicated no significant statistical difference, but Chao1, ACE, Shannon, and Simpson indices indicate a possible increase in bacterial richness for the spirulina diet. The most abundant bacteria in both experimental groups were Fusobacteriia with the only taxa from the genus Cetobacterium. The bacterium from genus Romboutsia was more likely to be found in the microbiome of fish fed the fishmeal diet. In spirulina-fed fish, the genera Plesiomonas and Bacteroides were the most dominant microbes observed. Even though some genera were more abundant in the spirulina group, the overall microbial community structure was not affected by diets.

Background: The locus for naked neck (Na) in chickens reduces feather coverage and leads to increased heat dissipation from the body surface resulting in better adaptability to hot conditions. However, the Na gene is linked to significantly lower hatchability due to an increased late embryonic mortality. It has been argued that the causative gene GDF7 may have a direct pleiotropic effect on hatchability via its effect on muscle development. Thus, the study presented here analyses the transcriptome of the hatching muscle (M. complexus) and shows how GDF7 impacts development leading to reduced hatching rates in Na chickens. Results: Using 12 chicken embryos (6 x wildtype (Wt) and 6 x Na) RNA was extracted from the M. complexus of each embryo and sequenced. The resulting differential expression analyses led to the discovery of 461 differentially expressed (DE) genes in the M. complexus of the experimental group. Among those, 77 genes were of uncertain function (LOC symbols), with 31 were classified as uncharacterised. The regulation of a number of pathways involved in normal embryonic development, were found to be negatively influenced by the Na genotype. Further pathways involved in cell-cell adhesion, cell signalling pathways, and amino acid (AA) metabolism/transport were also observed. GDF7 (alias BMP12), whose localised overexpression in the neck skin causes the Na/Na phenotype, was significantly overexpressed in the M. complexus of Na/Na embryos, and shows a significant increase in the number of binding sites for the transcription factor PITX2 was also observed. Conclusion: In Na chickens, GDF7 is under the control of a mutated cis-regulatory element, whose actions are known to suppress the development and distribution of feathers through the sensitizing action of retinoic acid. In this study, a number of DE genes with over 10 retinoic acid response elements (RAREs) in close proximity were observed, indicating changes to the retinol metabolism. With the understanding that the Na/Na mutation leads to increased retinoic acid activity, this indicates a high likelihood of GDF7 excerpting a direct pleiotropic effect, not just in the observed reduction in feather patterning, but also impacting the development of the M.complexus, and consequently leading to the reduced hatchability observed in birds with the Na/Na genotype. Furthermore, the enrichment of PITX2 binding sites in proximity to DE genes in the M. complexus, also indicates that muscle development is still ongoing in Na embryos. This suggests that the M. complexus is not yet fully developed, further increasing the potential for late embryonic mortality in Na chicks at hatching.