TLR2 and its co-receptors determine responses of macrophages and dendritic cells to lipoproteins of Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) signals through Toll-like receptor 2 (TLR2) to regulate antigen presenting cells (APCs). Mtb lipoproteins, including LpqH, LprA, LprG and PhoS1, are TLR2 agonists, but their co-receptor requirements are unknown. We studied Mtb lipoprotein-induced responses in TLR2^−/−, TLR1^−/−, TLR6^−/−, CD14^−/− and CD36^−/− macrophages. Responses to LprA, LprG, LpqH and PhoS1 were completely dependent on TLR2. LprG, LpqH, and PhoS1 were dependent on TLR1, but LprA did not require TLR1. None of the lipoproteins required TLR6, although a redundant contribution by TLR6 cannot be excluded. CD14 contributed to detection of LprA, LprG and LpqH, whereas CD36 contributed only to detection of LprA. Studies of lung APC subsets revealed lower TLR2 expression by CD11b^high/CD11c^low lung macrophages than CD11b^low/CD11c^high alveolar macrophages, which correlated with hyporesponsiveness of lung macrophages to LpqH. Thus, lung APC subsets differ in TLR expression, which may determine differences in responses to Mtb.     

Electronic sensory systems for taste and odour monitoring in water – Developments and limitations

Taste and odour causingchemicals in drinking water supplies can bedetected and identified using a variety ofanalytical techniques and sensory methods.Currently limitations exist in applying thesetechniques and methods to the continuousmonitoring of taste and odour episodes.Electronic sensory systems so called``electronic noses' using non-specific gassensors could offer a rapid and relative simpletechnique for continuous monitoring of waterquality. Laboratory and field-based continuouswater monitoring showed that introducedpollutants such as 2-chlorophenol and geosmincould be detected by a sensor array, howeverthe detection limits were significant higherthan the odour threshold concentrations (OTC)for the respective compounds. The conditioningof the monitoring system in a temperaturecontrolled environment for on-line headspacegeneration and transfer reduced the impact ofenvironmental fluctuations on the sensorresponse profiles. At present, a sensor arraybased monitoring system could be applied to theintake protection of taste and odour causingcompounds in water supplies with a minimum OTCof 10 ppm.