For preliminary isolation of nitrogen fixing bacteria, we have used one nitrogen free media. Is it confirmatory test? How can I confirm about the nitrogenase activity of the bacteria.
It will just give you some indication about the nitrogen fixing ability , but need confirmatory test for nitrogenase ..
And most important is to see , it is for asymbiotic or symbiotic , in latter case , it is much easier to have a look at root nodule formation ...
Using synthetic biology to increase nitrogenase activity(Microbial Cell Factories201615:43,https://doi.org/10.1186/s12934-016-0442-6)
Background : Nitrogen fixation has been established in protokaryotic model Escherichia coli by transferring a minimal nifgene cluster composed of 9 genes (nifB, nifH, nifD, nifK, nifE, nifN, nifX, hesA and nifV) from Paenibacillus sp. WLY78. However, the nitrogenase activity in the recombinant E. coli 78-7 is only 10 % of that observed in wild-type Paenibacillus. Thus, it is necessary to increase nitrogenase activity through synthetic biology.
Results: In order to increase nitrogenase activity in heterologous host, a total of 28 selected genes from Paenibacillussp. WLY78 and Klebsiella oxytoca were placed under the control of Paenibacillus nif promoter in two different vectors and then they are separately or combinationally transferred to the recombinant E. coli 78-7. Our results demonstrate that Paenibacillus suf operon (Fe–S cluster assembly) and the potential electron transport genes pfoAB, fldA and fer can increase nitrogenase activity. Also, K. oxytoca nifSU (Fe–S cluster assembly) and nifFJ (electron transport specific for nitrogenase) can increase nitrogenase activity. Especially, the combined assembly of the potential Paenibacillus electron transporter genes (pfoABfldA) with K. oxytocanifSU recovers 50.1 % of wild-type (Paenibacillus) activity. However, K. oxytoca nifWZM and nifQ can not increase activity.
Conclusion : The combined assembly of the potential Paenibacillus electron transporter genes (pfoABfldA) with K. oxytocanifSU recovers 50.1 % of wild-type (Paenibacillus) activity in the recombinant E. coli 78-7. Our results will provide valuable insights for the enhancement of nitrogenase activity in heterogeneous host and will provide guidance for engineering cereal plants with minimal nif genes.
It will just give you some indication about the nitrogen fixing ability , but need confirmatory test for nitrogenase ..
And most important is to see , it is for asymbiotic or symbiotic , in latter case , it is much easier to have a look at root nodule formation ...
Using synthetic biology to increase nitrogenase activity(Microbial Cell Factories201615:43,https://doi.org/10.1186/s12934-016-0442-6)
Background : Nitrogen fixation has been established in protokaryotic model Escherichia coli by transferring a minimal nifgene cluster composed of 9 genes (nifB, nifH, nifD, nifK, nifE, nifN, nifX, hesA and nifV) from Paenibacillus sp. WLY78. However, the nitrogenase activity in the recombinant E. coli 78-7 is only 10 % of that observed in wild-type Paenibacillus. Thus, it is necessary to increase nitrogenase activity through synthetic biology.
Results: In order to increase nitrogenase activity in heterologous host, a total of 28 selected genes from Paenibacillussp. WLY78 and Klebsiella oxytoca were placed under the control of Paenibacillus nif promoter in two different vectors and then they are separately or combinationally transferred to the recombinant E. coli 78-7. Our results demonstrate that Paenibacillus suf operon (Fe–S cluster assembly) and the potential electron transport genes pfoAB, fldA and fer can increase nitrogenase activity. Also, K. oxytoca nifSU (Fe–S cluster assembly) and nifFJ (electron transport specific for nitrogenase) can increase nitrogenase activity. Especially, the combined assembly of the potential Paenibacillus electron transporter genes (pfoABfldA) with K. oxytocanifSU recovers 50.1 % of wild-type (Paenibacillus) activity. However, K. oxytoca nifWZM and nifQ can not increase activity.
Conclusion : The combined assembly of the potential Paenibacillus electron transporter genes (pfoABfldA) with K. oxytocanifSU recovers 50.1 % of wild-type (Paenibacillus) activity in the recombinant E. coli 78-7. Our results will provide valuable insights for the enhancement of nitrogenase activity in heterogeneous host and will provide guidance for engineering cereal plants with minimal nif genes.
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