目的了解产气肠杆菌携带bla_(NDM-1)质粒的转移性、复制子分型及周围环境。方法产气肠杆菌HNNDM0711为实验菌株,利用接合实验研究其质粒的转移性,对接合子进行稳定性试验,采用质粒复制子分型法对质粒进行分型,利用染色体步移技术对基因b...目的了解产气肠杆菌携带bla_(NDM-1)质粒的转移性、复制子分型及周围环境。方法产气肠杆菌HNNDM0711为实验菌株,利用接合实验研究其质粒的转移性,对接合子进行稳定性试验,采用质粒复制子分型法对质粒进行分型,利用染色体步移技术对基因bla_(NDM-1)上下游进行测序,使用BLASTN和BLASTP对基因组序列进行比对,使用Vector NTI 11.5.1注释并生成序列管道图,序列通过软件Banklt递交至Genbank。结果产气肠杆菌HN-NDM0711接合实验阳性,阳性接合子稳定传代4 d后,所有克隆株对亚胺培南和美罗培南的最低抑菌浓度(MIC)均未发生变化,基因bla_(NDM-1)均为阳性。质粒复制子为IncA/C型;基因bla_(NDM-1)位于不常见的插入序列ISAba14和IS91之间,在bla_(NDM-1)的上游出现一个Tn3转座子和I型整合子,整合子上含有一个由庞大镶嵌序列构成的少见耐药基因盒。结论 IncA/C型质粒pHN-NDM0711携带基因bla_(NDM-1)及耐药基因盒,可能源于不同抗菌药物选择压力下的基因重组,建议严格控制临床、工业和农业抗菌药物的使用,从源头上减少此类细菌的产生。展开更多
Particle size distribution of coarse aggregates through mechanical sieving gives results in terms of cumu- lative mass percent. But digital image processing generated size distribution of particles, while being fast a...Particle size distribution of coarse aggregates through mechanical sieving gives results in terms of cumu- lative mass percent. But digital image processing generated size distribution of particles, while being fast and accurate, is often expressed in terms of area function or number of particles. In this paper, a mass model is developed which converts the image obtained size distribution to mass-wise distribution, mak- ing it readily comparable to mechanical sieving data. The concept of weight/particle ratio is introduced for mass reconstruction from 2D images of particle aggregates. Using this mass model, the effects of several particle shape parameters （such as major axis, minor axis, and equivalent diameter） on sieve-size of the particles is studied. It is shown that the sieve-size of a particle strongly depend upon the shape param- eters, 91% of its variation being explained by major axis, minor axis, bounding box length and equivalent diameter. Furthermore, minor axis gives an overall accurate estimate of particle sieve-size, error in mean size （D-50） being just 0.4%. However, sieve-size of smaller particles （〈20 ram） strongly depends upon the length of the smaller arm of the bounding box enclosing them and sieve-sizes of larger particles （〉20 mm） are highly correlated to their equivalent diameters. Multiple linear regression analysis has been used to generate overall mass-wise particle size distribution, considering the influences of all these shape parameters on particle sieve-size. Multiple linear regression generated overall mass-wise particle size distribution shows a strong correlation with sieve generated data. The adjusted R-square value of the regression analysis is found to be 99 percent （w.r,t cumulative frequency）. The method proposed in this paper provides a time-efficient way of producing accurate （up to 99%） mass-wise PSD using digital image processing and it can be used effectively to renlace the mechanical sieving.展开更多
文摘目的了解产气肠杆菌携带bla_(NDM-1)质粒的转移性、复制子分型及周围环境。方法产气肠杆菌HNNDM0711为实验菌株,利用接合实验研究其质粒的转移性,对接合子进行稳定性试验,采用质粒复制子分型法对质粒进行分型,利用染色体步移技术对基因bla_(NDM-1)上下游进行测序,使用BLASTN和BLASTP对基因组序列进行比对,使用Vector NTI 11.5.1注释并生成序列管道图,序列通过软件Banklt递交至Genbank。结果产气肠杆菌HN-NDM0711接合实验阳性,阳性接合子稳定传代4 d后,所有克隆株对亚胺培南和美罗培南的最低抑菌浓度(MIC)均未发生变化,基因bla_(NDM-1)均为阳性。质粒复制子为IncA/C型;基因bla_(NDM-1)位于不常见的插入序列ISAba14和IS91之间,在bla_(NDM-1)的上游出现一个Tn3转座子和I型整合子,整合子上含有一个由庞大镶嵌序列构成的少见耐药基因盒。结论 IncA/C型质粒pHN-NDM0711携带基因bla_(NDM-1)及耐药基因盒,可能源于不同抗菌药物选择压力下的基因重组,建议严格控制临床、工业和农业抗菌药物的使用,从源头上减少此类细菌的产生。
基金Indian Institute of Technology,Kharagpur in India for supporting this work
文摘Particle size distribution of coarse aggregates through mechanical sieving gives results in terms of cumu- lative mass percent. But digital image processing generated size distribution of particles, while being fast and accurate, is often expressed in terms of area function or number of particles. In this paper, a mass model is developed which converts the image obtained size distribution to mass-wise distribution, mak- ing it readily comparable to mechanical sieving data. The concept of weight/particle ratio is introduced for mass reconstruction from 2D images of particle aggregates. Using this mass model, the effects of several particle shape parameters （such as major axis, minor axis, and equivalent diameter） on sieve-size of the particles is studied. It is shown that the sieve-size of a particle strongly depend upon the shape param- eters, 91% of its variation being explained by major axis, minor axis, bounding box length and equivalent diameter. Furthermore, minor axis gives an overall accurate estimate of particle sieve-size, error in mean size （D-50） being just 0.4%. However, sieve-size of smaller particles （〈20 ram） strongly depends upon the length of the smaller arm of the bounding box enclosing them and sieve-sizes of larger particles （〉20 mm） are highly correlated to their equivalent diameters. Multiple linear regression analysis has been used to generate overall mass-wise particle size distribution, considering the influences of all these shape parameters on particle sieve-size. Multiple linear regression generated overall mass-wise particle size distribution shows a strong correlation with sieve generated data. The adjusted R-square value of the regression analysis is found to be 99 percent （w.r,t cumulative frequency）. The method proposed in this paper provides a time-efficient way of producing accurate （up to 99%） mass-wise PSD using digital image processing and it can be used effectively to renlace the mechanical sieving.
