Diana Stęgierska

Inflammatory bowel disease (IBD) is one of the most common causes of chronic clinical signs from the gastrointestinal tract, associated with histological evidence of inflammation in the lamina propria of the small and/or large intestine in cats. The underlying etiopathogenesis of this inflammation remains unclear. IBD is probably caused by a combination of environmental and immune factors in genetically susceptible individuals. The process of diagnosing IBD involves several steps and is based on the exclusion of other causes of gastrointestinal signs and on the confirmation of the presence of inflammatory infiltration in the intestinal wall by histopathological assessment of biopsies. The treatment is based on anti-inflammatory and immunosuppressive drugs. In addition, dietotherapy, antibiotics, antiparasitic drugs, prebiotics, probiotics and supplementation of vitamin b12 are also used. For most patients, the response to treatment is satisfactory, but the maintenance of clinical remission in most of them may require anti-inflammatory drugs for the rest of their lives.

The aim of study was to isolate, characterize and analyse the protein profiles of Myoviridae-like bacteriophages obtained from M. haemolytica using MALDI TOF mass spectrometry. The material consisted of the M. haemolytica reference strain ATCC® BAA410, reference serotypes A1, A2, A5, A6, A7, A9, and A11, and wild-type isolates of serotype A1. Bacteriophage morphology was examined with a transmission electron microscope. The proteins were separated in SDS-PAGE and two-dimensional electrophoresis and characterized by MALDI-TOF. Among the phages obtained, seven were specific for strains A1, A2, A5, A6, A7 and 25, and PHL-1 was specific for the BAA410 strain. The protein profiles for the phages were very similar to one another, but differed from the reference phage in that they lacked protein fractions with molecular weights of 22.9, 56.3 and 73.1 kDa. 2D electrophoresis revealed significant differences in the size of proteins and their localization in the pH gradient. The most similar profiles were observed in phages specific for strains BAA-410 and A6. In all profiles two main spots were observed in the molecular weight range from 44 to 70 kDa at pH < 4. The results indicate that 2D electrophoresis is a very useful tool for characterization of phage protein profiles. An important objective was to determine the molecular differences between morphologically similar phages belonging to one family and to find similarities to phages specific for other pathogens. The study also assessed the suitability of the methods used to characterize phages.