Characterisation of <Emphasis Type="Italic">mycobacteria</Emphasis> isolated from slaughter cattle in pastoral regions of Uganda

Background  

Bovine tuberculosis is a zoonotic problem in pastoral cattle and communities in Uganda. Tuberculin tests in pastoral cattle had shown a high herd but low animal prevalence, with a high proportion of avian reactors. No work had been done to identify the mycobacterial species involved. The objective of the study was to isolate and characterise Mycobacterial species causing tuberculous lesions in slaughtered animals. Lesioned organs compatible with bovine tuberculosis in slaughtered cattle from pastoral areas in Uganda were collected and cultured to isolate mycobacteria. AccuProbe culture identification kits for the Mycobacterium tuberculosis complex, M. avium complex and M. avium were used to identify the isolates. Spoligotyping and Insertion Sequence (IS) 1311 and IS1245 Restriction Fragment Length Polymorphism analysis (RFLP) were used to further characterise the isolates.     

The effect of ocean acidification on symbiont photorespiration and productivity in Acropora formosa

Ocean acidification is expected to lower the net accretion of coral reefs yet little is known about its effect on coral photophysiology. This study investigated the effect of increasing CO₂ on photosynthetic capacity and photoprotection in Acropora formosa. The photoprotective role of photorespiration within dinoflagellates (genus Symbiodinium) has largely been overlooked due to focus on the presence of a carbon‐concentrating mechanism despite the evolutionary persistence of a Form II Rubisco. The photorespiratory fixation of oxygen produces phosphoglycolate that would otherwise inhibit carbon fixation though the Calvin cycle if it were not converted to glycolate by phosphoglycolate phosphatase (PGPase). Glycolate is then either excreted or dealt with by enzymes in the photorespiratory glycolate and/or glycerate pathways adding to the pool of carbon fixed in photosynthesis. We found that CO₂ enrichment led to enhanced photoacclimation (increased chlorophyll a per cell) to the subsaturating light levels. Light‐enhanced dark respiration per cell and xanthophyll de‐epoxidation increased, with resultant decreases in photosynthetic capacity (P_nmax) per chlorophyll. The conservative CO₂ emission scenario (A1B; 600–790 ppm) led to a 38% increase in the P_nmax per cell whereas the ‘business‐as‐usual’ scenario (A1F1; 1160–1500 ppm) led to a 45% reduction in PGPase expression and no change in P_nmax per cell. These findings support an important functional role for PGPase in dinoflagellates that is potentially compromised under CO₂ enrichment.