Graphene oxide （GO） can be reduced to graphene in a normal aerobic setup under ambient conditions as mediated by microbial respiration of Shewanella cells. The microbially-reduced graphene （MRG） exhibited excellen...Graphene oxide （GO） can be reduced to graphene in a normal aerobic setup under ambient conditions as mediated by microbial respiration of Shewanella cells. The microbially-reduced graphene （MRG） exhibited excellent electrochemical properties. Extracellular electron transfer pathways at the cell/GO interface were systematically investigated, suggesting both direct electron transfer and electron mediators are involved in the GO reduction.展开更多
Social bees, like honeybees and bumblebees, have a close contact with nest mates of different developmental stages and generations. This could enhance bacterial transfer between nest mates and offers opportunities for...Social bees, like honeybees and bumblebees, have a close contact with nest mates of different developmental stages and generations. This could enhance bacterial transfer between nest mates and offers opportunities for direct transfer of symbionts from one generation to the next, resulting in a stable host specific gut microbiota. Gut sym- bionts of honeybees and bumblebees have been suggested to contribute in digestion and protection against parasites and pathogens. Here we studied the impact of contact with the bumblebee colony on the colonization potential of the bacterial families （i.e., Neisseri- aceae, Orbaceae, Lactobacillaceae and Bifidobacteriaceae） occurring in the gut of adult bumblebees （Bombus terrestris）. Bacterial profiles of the gut microbiota of B. terrestris were determined based on the hypervariable V4 region of the 16S rRNA using paired-end Illumina sequencing. In our experiments, we created different groups in which we grad- ually reduced the contact with nest mates and hive material. We made 3 observations： （i） reducing the contact between the colony and the bumblebee during adult life resulted in a significant drop in the relative abundance ofLactobacillus bombicola and Lactobacillus bombi; （ii） Bifidobacteriaceae required contact with nest mates to colonize the gut of B. terrestris and a significant lower bacterial diversity was observed in bumblebees that were completely excluded from colony contact during the adult life; （iii） Snodgrassella and Gilliamella were able to colonize the gut of the adult bumblebee without any direct contact with nest mates in the adult life stage. These results indicate the impact of the colony life on the diversity of the characteristic bumblebee gut bacteria.展开更多
Bacterial transfer is a concern when sharing food and drink, so to address this concern, this study examined the bacterial transfer onto and into plastic drinking cups. Two experiments were performed to: 1) test bacte...Bacterial transfer is a concern when sharing food and drink, so to address this concern, this study examined the bacterial transfer onto and into plastic drinking cups. Two experiments were performed to: 1) test bacterial transfer to the rim of a plastic drinking cup, and 2) test residual bacteria in the liquid that was consumed from the cup. Bacteria were enumerated from the cup rim and the water in the cup. The results for both types of transfer showed higher bacterial populations on cups exposed to drinking compared to those where no drinking occurred. However, there was more bacterial transfer to the rim of the plastic cup than the liquid inside the cup.展开更多
Popcorn is a very social food, often shared with others and offered at many major sporting events, concerts, movies, and fairs. However, sharing may not be safe since microorganisms found on hands may be transferred o...Popcorn is a very social food, often shared with others and offered at many major sporting events, concerts, movies, and fairs. However, sharing may not be safe since microorganisms found on hands may be transferred onto the shared popcorn. This study was conducted to determine if bacteria are transferred from hands to popcorn during handling. Over 30 samplings revealed that bacterial transfer to popcorn from hands was very low;however transfer did occur with large variation between subjects. Since hands and surfaces can carry bacteria in situations where food is being shared, transferring bacteria from one person to another person is always a risk.展开更多
The elongation factor Tu （EF-Tu） receptor （EFR） in cruciferous plants specifically recognizes the N-terminal acetylated elf18 region of bacterial EF-Tu and thereby activates plant immunity. It has been demonstrate...The elongation factor Tu （EF-Tu） receptor （EFR） in cruciferous plants specifically recognizes the N-terminal acetylated elf18 region of bacterial EF-Tu and thereby activates plant immunity. It has been demonstrated that Arabidopsis EFR confers broad-spectrum bacterial resistance in the EFR transgenic solanaceous plants. Here, the transgenic rice plants （Oryza sativa L. ssp. japonica cv. Zhonghua 17） and cell cultures with constitutive expression of AtEFR were developed to investigate whether AtEFR senses EF-Tu and thus enhances bacterial resistance in the monocot plants. We＇demonstrated that the Xanthomonas oryzae-derived elf18 peptide induced oxidative burst and mitogen-activated protein kinase activa- tion in the AtEFR transgenic rice cells and plants, respectively. Pathogenesis-related genes, such as OsPBZ1, were upregulated dramatically in transgenic rice plant and cell lines in response to elf18 stimulation. Importantly, pretreatment with elf18 trig- gered strong resistance to X. oryzae pv. oryzae in the transgenic plants, which was largely dependent on the AtEFR expressionlevel. These plants also exhibited enhanced resistance to rice bacterial brown stripe, but not to rice fungal blast. Collectively, the results indicate that the rice plants with heterologous expression of AtEFR recognize bacterial EF-Tu and exhibit enhanced broad-spectrum bacterial disease resistance and that pattern recognition receptor-mediated immunity may be manipulated across the two plant classes, dicots and monocots.展开更多
基金Y. L. acknowledges the financial support of this work in part by national science foundation （NSF） （No. CBET 1034222） and faculty research funds granted by the University of California, Santa Cruz. XPS was performed at the Center for Nanoscale Systems at Harvard University, which is supported by the NSF （No. ECS-0335765）. We thank H. Lin of Harvard University for technical assistance. Work at Lawrence Livermore National Laboratory was conducted under Contract No. DE-AC52-07NA27344.
文摘Graphene oxide （GO） can be reduced to graphene in a normal aerobic setup under ambient conditions as mediated by microbial respiration of Shewanella cells. The microbially-reduced graphene （MRG） exhibited excellent electrochemical properties. Extracellular electron transfer pathways at the cell/GO interface were systematically investigated, suggesting both direct electron transfer and electron mediators are involved in the GO reduction.
文摘Social bees, like honeybees and bumblebees, have a close contact with nest mates of different developmental stages and generations. This could enhance bacterial transfer between nest mates and offers opportunities for direct transfer of symbionts from one generation to the next, resulting in a stable host specific gut microbiota. Gut sym- bionts of honeybees and bumblebees have been suggested to contribute in digestion and protection against parasites and pathogens. Here we studied the impact of contact with the bumblebee colony on the colonization potential of the bacterial families （i.e., Neisseri- aceae, Orbaceae, Lactobacillaceae and Bifidobacteriaceae） occurring in the gut of adult bumblebees （Bombus terrestris）. Bacterial profiles of the gut microbiota of B. terrestris were determined based on the hypervariable V4 region of the 16S rRNA using paired-end Illumina sequencing. In our experiments, we created different groups in which we grad- ually reduced the contact with nest mates and hive material. We made 3 observations： （i） reducing the contact between the colony and the bumblebee during adult life resulted in a significant drop in the relative abundance ofLactobacillus bombicola and Lactobacillus bombi; （ii） Bifidobacteriaceae required contact with nest mates to colonize the gut of B. terrestris and a significant lower bacterial diversity was observed in bumblebees that were completely excluded from colony contact during the adult life; （iii） Snodgrassella and Gilliamella were able to colonize the gut of the adult bumblebee without any direct contact with nest mates in the adult life stage. These results indicate the impact of the colony life on the diversity of the characteristic bumblebee gut bacteria.
文摘Bacterial transfer is a concern when sharing food and drink, so to address this concern, this study examined the bacterial transfer onto and into plastic drinking cups. Two experiments were performed to: 1) test bacterial transfer to the rim of a plastic drinking cup, and 2) test residual bacteria in the liquid that was consumed from the cup. Bacteria were enumerated from the cup rim and the water in the cup. The results for both types of transfer showed higher bacterial populations on cups exposed to drinking compared to those where no drinking occurred. However, there was more bacterial transfer to the rim of the plastic cup than the liquid inside the cup.
文摘Popcorn is a very social food, often shared with others and offered at many major sporting events, concerts, movies, and fairs. However, sharing may not be safe since microorganisms found on hands may be transferred onto the shared popcorn. This study was conducted to determine if bacteria are transferred from hands to popcorn during handling. Over 30 samplings revealed that bacterial transfer to popcorn from hands was very low;however transfer did occur with large variation between subjects. Since hands and surfaces can carry bacteria in situations where food is being shared, transferring bacteria from one person to another person is always a risk.
基金supported by the 973 program 2011CB100700the transgenic crop project 2012ZX08009003+1 种基金the National Natural Science Foundation of China grant 31272007the Key Project in the National Science and Technology Pillar Program 2012BAD19B03 to W.S
文摘The elongation factor Tu （EF-Tu） receptor （EFR） in cruciferous plants specifically recognizes the N-terminal acetylated elf18 region of bacterial EF-Tu and thereby activates plant immunity. It has been demonstrated that Arabidopsis EFR confers broad-spectrum bacterial resistance in the EFR transgenic solanaceous plants. Here, the transgenic rice plants （Oryza sativa L. ssp. japonica cv. Zhonghua 17） and cell cultures with constitutive expression of AtEFR were developed to investigate whether AtEFR senses EF-Tu and thus enhances bacterial resistance in the monocot plants. We＇demonstrated that the Xanthomonas oryzae-derived elf18 peptide induced oxidative burst and mitogen-activated protein kinase activa- tion in the AtEFR transgenic rice cells and plants, respectively. Pathogenesis-related genes, such as OsPBZ1, were upregulated dramatically in transgenic rice plant and cell lines in response to elf18 stimulation. Importantly, pretreatment with elf18 trig- gered strong resistance to X. oryzae pv. oryzae in the transgenic plants, which was largely dependent on the AtEFR expressionlevel. These plants also exhibited enhanced resistance to rice bacterial brown stripe, but not to rice fungal blast. Collectively, the results indicate that the rice plants with heterologous expression of AtEFR recognize bacterial EF-Tu and exhibit enhanced broad-spectrum bacterial disease resistance and that pattern recognition receptor-mediated immunity may be manipulated across the two plant classes, dicots and monocots.
