Alpha-glucosidase is synthesized in the hypopharyngeal glands located in the head of worker bees including Apisflorea. To analyze the developmental stage-specific expression of the a-glucosidase gene inA.florea, total...Alpha-glucosidase is synthesized in the hypopharyngeal glands located in the head of worker bees including Apisflorea. To analyze the developmental stage-specific expression of the a-glucosidase gene inA.florea, total RNA was isolated from eggs, and the heads of nurse and forager bees. By reverse transcription polymerase chain reaction （RT- PCR）, it was shown that the highest expression levels of the a-glucosidase Ⅲ gene, in the three examined developmental stadia, were found in forager bees, with much lower expression levels in nurse bees and no detectable expression in eggs. A complete aglucosidase III eDNA was obtained by RT-PCR and sequenced. The 1 701 bp eDNA nucleotide sequence and the predicted 567 amino acids it encodes were assayed by BLASTn, BLASTp and BLASTx programs and revealed a 95% and 94% similarity to the A. mellifera aglucosidase III gene at the DNA and amino acid sequence levels, respectively. For purification of the active encoded enzyme, forager bee heads were homogenized in sodium phosphate buffer solution and the crude extract （0.30 U/mg） sequentially precipitated with 95% saturated ammonium sulfate （0.18 U/mg）, and purified by DEAE cellulose ion exchange chromatography （0.17 U/mg）, and gel filtration on Superdex 200 （0.52 U/mg）. After resolution through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a single enzymically active band （73 kDa） was identified from renatured substrate gels. Excision of this band, elution of the protein and tryptic peptide digestives identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry （MALDI-TOF MS） revealed six matching masses to the A. mellifera （Q17958） and predicted A.florea α glucosidase Ⅲ protein with 12% coverage, supporting the probable purification of the same α-glucosidase III protein as that encoded by the cloned cDNA.展开更多
Propolis collected by stingless bees from various types of plants has been used as an antimicrobial agent in several previous studies. We assessed the effect of propolis produced by a stingless bee, Trigona apicalis, ...Propolis collected by stingless bees from various types of plants has been used as an antimicrobial agent in several previous studies. We assessed the effect of propolis produced by a stingless bee, Trigona apicalis, on Apis florea experimentally infected with Nosema ceranae, a parasite of honeybees. For parasite inoculation each Nosema free-bee was fed 2μL of 50% （w/v） sucrose solution containing N. ceranae spores at 40,000 spores/bee and 0 as a negative control （CO）. Treated bees were provided with 0%, 10%, 20% and 50% propolis （w/v） in water, defined as 0P, 10P, 20P and 50P, respectively. We assessed the effects of propolis 14 days post inoculation. All propolis-treated bees had significantly higher survival than untreated bees. However, survival of Nosema-inoculated bees was lower than that of control bees. Bees treated with the highest propolis concentration （50P） had the highest survival ratio. No control bees became infected over the course of the study. However, N. ceranae infection rates of bees treated with 0P, 10P, 20P and 50P were 75 ± 1.4%, 72 ± 5.6%, 69± 4.2% and 47± 1.4%, respectively. In addition, propolis-treated bees had hypopharyngeal gland protein content that was significantly higher than 0P and CO bees. Overall, propolis treatment significantly reduced N. ceranae infection rate and bee mortality and was associated with increased hypopharyngeal gland protein concentration.展开更多
文摘Alpha-glucosidase is synthesized in the hypopharyngeal glands located in the head of worker bees including Apisflorea. To analyze the developmental stage-specific expression of the a-glucosidase gene inA.florea, total RNA was isolated from eggs, and the heads of nurse and forager bees. By reverse transcription polymerase chain reaction （RT- PCR）, it was shown that the highest expression levels of the a-glucosidase Ⅲ gene, in the three examined developmental stadia, were found in forager bees, with much lower expression levels in nurse bees and no detectable expression in eggs. A complete aglucosidase III eDNA was obtained by RT-PCR and sequenced. The 1 701 bp eDNA nucleotide sequence and the predicted 567 amino acids it encodes were assayed by BLASTn, BLASTp and BLASTx programs and revealed a 95% and 94% similarity to the A. mellifera aglucosidase III gene at the DNA and amino acid sequence levels, respectively. For purification of the active encoded enzyme, forager bee heads were homogenized in sodium phosphate buffer solution and the crude extract （0.30 U/mg） sequentially precipitated with 95% saturated ammonium sulfate （0.18 U/mg）, and purified by DEAE cellulose ion exchange chromatography （0.17 U/mg）, and gel filtration on Superdex 200 （0.52 U/mg）. After resolution through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a single enzymically active band （73 kDa） was identified from renatured substrate gels. Excision of this band, elution of the protein and tryptic peptide digestives identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry （MALDI-TOF MS） revealed six matching masses to the A. mellifera （Q17958） and predicted A.florea α glucosidase Ⅲ protein with 12% coverage, supporting the probable purification of the same α-glucosidase III protein as that encoded by the cloned cDNA.
文摘Propolis collected by stingless bees from various types of plants has been used as an antimicrobial agent in several previous studies. We assessed the effect of propolis produced by a stingless bee, Trigona apicalis, on Apis florea experimentally infected with Nosema ceranae, a parasite of honeybees. For parasite inoculation each Nosema free-bee was fed 2μL of 50% （w/v） sucrose solution containing N. ceranae spores at 40,000 spores/bee and 0 as a negative control （CO）. Treated bees were provided with 0%, 10%, 20% and 50% propolis （w/v） in water, defined as 0P, 10P, 20P and 50P, respectively. We assessed the effects of propolis 14 days post inoculation. All propolis-treated bees had significantly higher survival than untreated bees. However, survival of Nosema-inoculated bees was lower than that of control bees. Bees treated with the highest propolis concentration （50P） had the highest survival ratio. No control bees became infected over the course of the study. However, N. ceranae infection rates of bees treated with 0P, 10P, 20P and 50P were 75 ± 1.4%, 72 ± 5.6%, 69± 4.2% and 47± 1.4%, respectively. In addition, propolis-treated bees had hypopharyngeal gland protein content that was significantly higher than 0P and CO bees. Overall, propolis treatment significantly reduced N. ceranae infection rate and bee mortality and was associated with increased hypopharyngeal gland protein concentration.
