A combination of Tropilaelaps mercedesae and imidacloprid negatively affects survival, pollen consumption and midgut bacterial composition of honey bee.

Tropilaelaps mercedesae is not only a major threat to honey bees in Asia but also a potential risk to global apiculture due to trade. Imidacloprid is a systemic insecticide that negatively affects individual bees. Moreover, the health of honey bees may be threatened by imidacloprid exposure and T. mercedesae infestation. We studied the effects of T. mercedesae and imidacloprid on the survival, food consumption and midgut bacterial diversity of Apis mellifera in the laboratory. Illumina 16S rRNA gene sequencing was used to determine the bacterial composition in the honey bee midgut. T. mercedesae decreased survival in parasitized honey bees compared with nonparasitized honey bees, but there was no significant difference in food consumption. The imidacloprid 50 µg/L diet significantly decreased syrup consumption of A. mellifera compared with the control diet. The combination of T. mercedesae infestation and imidacloprid 50 µg/L exposure reduced survival and increased pollen consumption of A. mellifera. T. mercedesae infestation or a combination of T. mercedesae infestation and exposure to 25 µg/L imidacloprid affected the midgut bacterial composition of honey bees. T. mercedesae infestation and imidacloprid exposure may reduce the survival and affect honey bee health.

The effect of Bt Cry9Ee toxin on honey bee brood and adults reared in vitro, Apis mellifera (Hymenoptera: Apidae).

The effects of Bt Cry9Ee toxin on honey bee, Apis mellifera L., survival, developmental rate, larval weight, pollen consumption, and midgut bacterial diversity were tested in the laboratory. Honey bee larvae and adults were reared in vitro and fed a diet that contained Cry9Ee toxin at 0.01, 0.1, 1, and 10 mg/L. Cry9Ee toxin 0.01, 0.1, and 1 mg/L in diet used in this study may represent a value closer to field relevance and the highest concentration is unlikely to be encountered in the field and thus represent a worst case scenario. The dependent variables were compared for groups of honey bees feeding on treated diet and those feeding on negative control (no addition of a test substance), solvent control (0.01 mM Na2CO3), and positive control diet (dimethoate 45 mg/L). Bt Cry9Ee toxin did not affect survival or larval weight, and the result was great confidence in accepting the null hypothesis by power analysis. The effect on development rates and pollen consumption were the inconclusive results because the post-hoc power was less than 0.8. Furthermore, the midgut bacterial structure and compositions were determined using high-throughput sequencing targeting the V3-V4 regions of the 16S rDNA. All core honey bee intestinal bacterial class such as γ-Proteobacteria, Actinobacteria, α-Proteobacteria, Bacilli, ß-Proteobacteria, and Bacteroidia were detected, and no significant changes were found in the species diversity and richness between Cry9Ee treatments and laboratory control.

[Effects of acupuncture pre-conditioning on apoptosis in hippocampal neurons following ischemia-reperfusion injury in aged rats].

OBJECTIVE: To investigate the effects of acupuncture pre-conditioning on apoptosis in hippocampal neurons following ischemia-reperfusion injury in aged rats. METHODS: A total of 120 senile male Wistar rats aged 19 - 21 months (corresponding to 60-year-old human being) weighting 550 - 710 g were randomly divided into 4 groups (n = 30 each). Cerebral ischemic group: 4-vessel-block was conducted for 4 minutes to establish cerebral ischemic models; Acupuncture pre-conditioning group: electroacupuncture was applied at acupoint Baihui (GV20) with a frequency of 15 Hz and 2 mA for 30 minutes once daily for 5 days. Then the rats received 4-vessel-block for 4 minutes; Sham-operation group: 4 vessels were exposed; Sham-acupuncture group: only electroacupuncture for 5 days without operation. The rats were sacrificed at the end of predetermined duration of reperfusion 12 h, 1, 2, 3 and 7 d respectively. The brains were immediately harvested and hippocampal CA1 region was isolated for (1) light and electron microscopic examinations of hippocampal neurons; (2) detection of apoptotic neurons (TUNEL); (3) determination of caspase-3 protein expression with SABC (streptavidin-biotin-peroxidase complex) immuno-histochemical technique. RESULTS: There were apoptotic neurons in all groups. The numbers of apoptotic neurons and positive neurons of caspase-3 significantly increased in the acupuncture pre-conditioning and cerebral ischemic groups versus the sham-acupuncture and sham-operation groups (P < 0.01). And the numbers of apoptotic neurons and positive neurons of caspase-3 significantly decreased in the acupuncture pre-conditioning group versus the cerebral ischemic group (P < 0.01). CONCLUSION: Acupuncture pre-conditioning can decrease the neuronal apoptosis after ischemia-reperfusion injury through a lowered expression of caspase-3 protein in senile rats.