Induced thiacloprid insensitivity in honeybees (Apis mellifera L.) is associated with up-regulation of detoxification genes.

Honey bees, Apis mellifera, are markedly less sensitive to neonicotinoid insecticides containing a cyanoimino pharmacophore than to those with a nitroimino group. Although previous work has suggested that this results from enhanced metabolism of the former by detoxification enzymes, the specific enzyme(s) involved remain to be characterized. In this work, a pretreatment of honey bees with a sublethal dose of thiacloprid resulted in induced insensitivity to the same compound immediately following thiacloprid feeding. A longer pretreatment time resulted in no, or increased, sensitivity. Transcriptome profiling, using microarrays, identified a number of genes encoding detoxification enzymes that were over-expressed significantly in insecticide-treated bees compared with untreated controls. These included five P450s, CYP6BE1, CYP305D1, CYP6AS5, CYP315A1, CYP301A1, and a carboxyl/cholinesterase (CCE) CCE8. Four of these P450s were functionally expressed in Escherichia coli and their ability to metabolize thiacloprid examined by liquid chromatography-mass spectrometry (LC-MS) analysis.

Salivary peroxidase activity in whole saliva of patients with insulin-dependent (type-1) diabetes mellitus.

In this study, salivary peroxidase activity was measured in a group of 10 patients with insulin-dependent (type I) diabetes mellitus (IDDM) who had a tendency towards periodontitis. In healthy subjects (N : 10), mean salivary peroxidase activity was 0.0025 +/- 0.001 IU/ml, while in this group of type I diabetic patients it was 0.051 +/- 0.015 IU/ml, a significantly higher level (p < 0.001). Approximal plaque index (API), modified sulcus bleeding index (mod SBI) and pocket depths were assessed clinically. The values for mod SBI and API were 60% and 68% respectively for the diabetic patients while for the control group mod SBI was measured 0.0% and the value for API was 10.67% (p < 0.001). The administration of this simple and practical test may provide an early marker of a tendency towards periodontitis in IDDM patients.

The role of instrumental responses in memory retrieval in a T-maze.

Retrieval of the memory of non-reward on a rewarded trial was investigated here employing rats in a T-maze. A forced choice procedure was used. The daily rewarded (R) and non-rewarded (N) trials always occurred in a fixed order, two R, four N, and finally two R, i.e. the series was R1-R2-N1-N2-N3-N4-R3-R4. In an original acquisition phase. Trial N4 of the series having occurred in a particular spatial alternative, e.g. left, it was followed by R3 either in the same alternative, Groups C and T, or in the opposite alternative, Group R. Group T, unlike Groups C and R, received a relatively long intertrial interval between N4 and R3. In a shift phase, groups were treated as in original acquisition except that the long intertrial interval (Group T) and the change in response (Group R) now occurred between R3 and R4 rather than N4 and R3. The major finding in original acquisition was slower running by Groups T and R than by Group C on Trials N2, N3, and N4. In shift, differences between the groups disappeared. These findings are consistent with the hypothesis that response-produced cues contribute to memory retrieval.