Bacteria growth depends crucially on protein synthesis,which is limited by ribosome synthesis.Ribosomal RNA(rRNA)transcription is the rate-limiting step of ribosome synthesis.It is generally proposed that the transcri...Bacteria growth depends crucially on protein synthesis,which is limited by ribosome synthesis.Ribosomal RNA(rRNA)transcription is the rate-limiting step of ribosome synthesis.It is generally proposed that the transcriptional initiation rate of rRNA operon is the primary factor that controls the r RNA synthesis.In this study,we established a convenient GFP-based reporter approach for measuring the bacterial rRNA chain elongation rate.We showed that the rRNA chain elongation rate of Escherichia coli remains constant under nutrient limitation and chloramphenicol inhibition.In contrast,rRNA chain elongation rate decreases dramatically under low temperatures.Strikingly,we found that Vibrio natriegens,the fastest growing bacteria known,has a 50%higher rRNA chain elongation rate than E.coli,which contributes to its rapid ribosome synthesis.Our study demonstrates that r RNA chain elongation rate is another important factor that affects the bacterial ribosome synthesis capacity.展开更多
Radiometric normalization,as an essential step for multi-source and multi-temporal data processing,has received critical attention.Relative Radiometric Normalization(RRN)method has been primarily used for eliminating ...Radiometric normalization,as an essential step for multi-source and multi-temporal data processing,has received critical attention.Relative Radiometric Normalization(RRN)method has been primarily used for eliminating the radiometric inconsistency.The radiometric trans-forming relation between the subject image and the reference image is an essential aspect of RRN.Aimed at accurate radiometric transforming relation modeling,the learning-based nonlinear regression method,Support Vector machine Regression(SVR)is used for fitting the complicated radiometric transforming relation for the coarse-resolution data-referenced RRN.To evaluate the effectiveness of the proposed method,a series of experiments are performed,including two synthetic data experiments and one real data experiment.And the proposed method is compared with other methods that use linear regression,Artificial Neural Network(ANN)or Random Forest(RF)for radiometric transforming relation modeling.The results show that the proposed method performs well on fitting the radiometric transforming relation and could enhance the RRN performance.展开更多
Use of 16S-23S intergenic transcribed spacer (ITS) variability,as a relatively new method,is becoming an important supplement to the molecular methods based on 16S rRNA for which has a fairly constant size and is not ...Use of 16S-23S intergenic transcribed spacer (ITS) variability,as a relatively new method,is becoming an important supplement to the molecular methods based on 16S rRNA for which has a fairly constant size and is not divergent enough to give good separation in close relationships. This paper summarizes the structures and characteristics of ITS regions that are extremely variable in copy number,length and sequence per genome. The ITS region can be amplified easily taking advantage of conserved nucleotide stretches at the 5’ of the 16S and 3’ of the 23S gene,and the amplicon can contain different amounts of the 16S rDNA by choosing primers at different conserved areas within this gene. These primers are listed and discussed for perfecting the methodology of ITS. Furthermore,some recent progresses on the taxonomy,identification and community analysis of bacteria by means of ITS in epidemiology,ecology and artificial environment are reviewed,as well,the virtues and limitations of that method are discussed. Fig 2,Tab 1,Ref展开更多
基金the National Natural Science Foundation of China(31700089,31700039,31870028 and 31970027)self-determined research funds of CCNU from the colleges’basic research and operation of MOE(CCNU18KFY01,CCNU19TS028 and CCNU20TS023)。
文摘Bacteria growth depends crucially on protein synthesis,which is limited by ribosome synthesis.Ribosomal RNA(rRNA)transcription is the rate-limiting step of ribosome synthesis.It is generally proposed that the transcriptional initiation rate of rRNA operon is the primary factor that controls the r RNA synthesis.In this study,we established a convenient GFP-based reporter approach for measuring the bacterial rRNA chain elongation rate.We showed that the rRNA chain elongation rate of Escherichia coli remains constant under nutrient limitation and chloramphenicol inhibition.In contrast,rRNA chain elongation rate decreases dramatically under low temperatures.Strikingly,we found that Vibrio natriegens,the fastest growing bacteria known,has a 50%higher rRNA chain elongation rate than E.coli,which contributes to its rapid ribosome synthesis.Our study demonstrates that r RNA chain elongation rate is another important factor that affects the bacterial ribosome synthesis capacity.
基金This research was funded by the National Natural Science Fund of China[grant number 41701415]Science fund project of Wuhan Institute of Technology[grant number K201724]Science and Technology Development Funds Project of Department of Transportation of Hubei Province[grant number 201900001].
文摘Radiometric normalization,as an essential step for multi-source and multi-temporal data processing,has received critical attention.Relative Radiometric Normalization(RRN)method has been primarily used for eliminating the radiometric inconsistency.The radiometric trans-forming relation between the subject image and the reference image is an essential aspect of RRN.Aimed at accurate radiometric transforming relation modeling,the learning-based nonlinear regression method,Support Vector machine Regression(SVR)is used for fitting the complicated radiometric transforming relation for the coarse-resolution data-referenced RRN.To evaluate the effectiveness of the proposed method,a series of experiments are performed,including two synthetic data experiments and one real data experiment.And the proposed method is compared with other methods that use linear regression,Artificial Neural Network(ANN)or Random Forest(RF)for radiometric transforming relation modeling.The results show that the proposed method performs well on fitting the radiometric transforming relation and could enhance the RRN performance.
文摘Use of 16S-23S intergenic transcribed spacer (ITS) variability,as a relatively new method,is becoming an important supplement to the molecular methods based on 16S rRNA for which has a fairly constant size and is not divergent enough to give good separation in close relationships. This paper summarizes the structures and characteristics of ITS regions that are extremely variable in copy number,length and sequence per genome. The ITS region can be amplified easily taking advantage of conserved nucleotide stretches at the 5’ of the 16S and 3’ of the 23S gene,and the amplicon can contain different amounts of the 16S rDNA by choosing primers at different conserved areas within this gene. These primers are listed and discussed for perfecting the methodology of ITS. Furthermore,some recent progresses on the taxonomy,identification and community analysis of bacteria by means of ITS in epidemiology,ecology and artificial environment are reviewed,as well,the virtues and limitations of that method are discussed. Fig 2,Tab 1,Ref
