Emulsion-Based Postbiotic Formulation Is Comparable to Viable Cells in Eliciting a Localized Immune Response in Dairy Cows With Chronic Mastitis.

Bovine mastitis is a disease with a multi-etiological nature, defined as an infection and inflammation of the udder. Mastitis represents a significant ongoing concern in the dairy industry, leading to substantial losses in profits and revenue for farmers worldwide. The predominant causes of bovine mastitis include the pathogens Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus uberis, and Escherichia coli. Antibiotic administration is currently the main treatment option for mastitis. However, there is a pressing need for alternative therapies to treat and prevent the disease, especially with the emergence of antibiotic-resistant, mastitis-causing pathogens, resulting in antibiotic treatment failure. One such example is live bio-therapeutics (also known as probiotics), such as Lactococcus lactis DPC3147. The efficacy of this live bio-therapeutic has been demonstrated in several previous trials by our group. The most recent of these trials showed that an emulsion-based formulation of this strain was as effective as a commercial antibiotic formulation in treating sub-clinical and clinical cases of bovine mastitis. Here, we report the results of a follow-up field trial, in which we sought to gain insight into the mechanism of action of such live bio-therapeutics, focussing on chronic mastitis cases. We treated 28 cows with chronic mastitis with two separate emulsion-based formulations containing either viable L. lactis DPC3147 cells (15 cows) or heat-killed L. lactis DPC3147 cells (13 cows). We then evaluated the efficacies of the two formulations (two treatment groups) in terms of stimulating a localized immune response (quantified by measuring IL-8 concentrations in milk collected from udders affected by mastitis) and efficacies in terms of cure rates (quantified by reductions in somatic cell counts and absence of pathogens). We demonstrate that the presence of heat-inactivated bacteria (a postbiotic) was as effective as the live bio-therapeutic in eliciting a localized immune response in cows with chronic mastitis. The response to heat-killed cells (postbiotic) reported herein could have beneficial implications for farmers with regard to prolonging the shelf life of such emulsion-based formulations containing heat-killed cells of L. lactis DPC3147 for curing cows with mastitis.

Pre-formulation and delivery strategies for the development of bacteriocins as next generation antibiotics.

Bacteriocins, a class of antimicrobial peptide produced by bacteria, may offer a potential alternative to traditional antibiotics, an important step towards mitigating the ever-increasing antimicrobial resistance crisis. They are active against a range of clinically relevant Gram-positive and Gram-negative bacteria. Bacteriocins have been discussed in the literature for over a century. Although they are used as preservatives in food, no medicine based on their antimicrobial activity exists on the market today. In order to formulate them into clinical antibiotics, pre-formulation studies on their biophysical and physicochemical properties that will influence their activity in vivo and their stability during manufacture must be elucidated. Thermal, pH and enzymatic stability of bacteriocins are commonly studied and regularly reported in the literature. Solubility, permeability and aggregation properties on the other hand are less frequently reported for many bacteriocins, which may contribute to their poor clinical progression. Promising cytotoxicity studies report that bacteriocins exhibit few cytotoxic effects on a variety of mammalian cell lines, at active concentrations. This review highlights the lack of quantitative data and in many cases even qualitative data, on bacteriocins' solubility, stability, aggregation, permeability and cytotoxicity. The formulation strategies that have been explored to date, proposed routes of administration, trends in in vitro/in vivo behaviour and efforts in clinical development are discussed. The future promise of bacteriocins as a new generation of antibiotics may require tailored local delivery strategies to fulfil their potential as a force to combat antimicrobial-resistant bacterial infections.

Proteogenomics of synaptosomal mitochondrial oxidative stress.

Oxidative stress is frequently implicated in the pathology of neurodegenerative disease. The chief source of this stress is mitochondrial respiration, via the passage of reducing equivalents through the respiratory chain resulting in a small but potentially pathological production of superoxide. The superoxide that is produced during normal respiration is primarily detoxified within the mitochondria by superoxide dismutase 2 (Sod2), a key protein for maintaining mitochondrial function. Mitochondria are distributed throughout the soma of neurons, as well as along neuronal processes and at the synaptic terminus. This distribution of potentially independent mitochondria throughout the neuron, at distinct subcellular locations, allows for the possibility of regional subcellular deficits in mitochondrial function. There has been increasing interest in the quantification and characterization of messages and proteins at the synapse, because of its importance in neurodegenerative disease, most notably Alzheimer disease. Here, we report the transcriptomic and proteomic changes that occur in synaptosomes from frontal cortices of Sod2 null mice. Constitutively Sod2 null mice were differentially dosed with the synthetic catalytic antioxidant EUK-189, which can extend the life span of these mice, as well as uncovering or preventing neurodegeneration due to endogenous oxidative stress. This approach facilitated insight into the quantification of trafficked messages and proteins to the synaptosome. We used two complementary methods to investigate the nature of the synaptosome under oxidative stress: either whole-genome gene expression microarrays or mass spectrometry-based proteomics using isobaric tagging for relative and absolute quantitation of proteins. We characterized the relative enrichment of gene ontologies at both gene and protein expression levels that occurs from mitochondrial oxidative stress in the synaptosome, which may lead to new avenues of investigation in understanding the regulation of synaptic function in normal and diseased states. As a result of using these approaches, we report for the first time an activation of the mTOR pathway in synaptosomes isolated from Sod2 null mice, confirmed by an upregulation of the phosphorylation of 4E-BP1.