cis- and trans-acting elements involved in regulation of norB (norZ), the gene encoding nitric oxide reductase in Neisseria gonorrhoeae

Microbiology ◽  
2008 ◽  
Vol 154 (1) ◽  
pp. 226-239 ◽  
Author(s):  
Vincent Isabella ◽  
Lori F. Wright ◽  
Kenneth Barth ◽  
Janice M. Spence ◽  
Susan Grogan ◽  
...  
2002 ◽  
Vol 68 (2) ◽  
pp. 668-672 ◽  
Author(s):  
Andrea B�sch ◽  
B�rbel Friedrich ◽  
Rainer Cramm

ABSTRACT A norB gene encoding a putative nitric oxide reductase is present in the genome of the nondenitrifying cyanobacterium Synechocystis sp. strain PCC6803. The gene product belongs to the quinol-oxidizing single-subunit class of nitric oxide reductases, discovered recently in the denitrifier Ralstonia eutropha. Heterologous complementation of a nitric oxide reductase-negative mutant of R. eutropha with norB from Synechocystis restored nitric oxide reductase activity. With reduced menadione as the electron donor, an enzymatic activity of 101 nmol of NO per min per mg of protein was obtained with membrane fractions of Synechocystis wild-type cells. Virtually no nitric oxide reductase activity was present in a norB-negative mutant of Synechocystis. Growing cells of this mutant are more sensitive toward NO than wild-type cells, indicating that the presence of a nitric oxide reductase is beneficial for Synechocystis when the cells are exposed to NO. Transcriptional fusions with the chloramphenicol acetyltransferase reporter gene were constructed to monitor norB expression in Synechocystis. Transcription of norB was not enhanced by the addition of the NO-generating agent sodium nitroprusside.


2000 ◽  
Vol 68 (9) ◽  
pp. 5241-5246 ◽  
Author(s):  
Tracey C. Householder ◽  
Elizabeth M. Fozo ◽  
Jean A. Cardinale ◽  
Virginia L. Clark

ABSTRACT The gene encoding a nitric oxide reductase has been identified inNeisseria gonorrhoeae. The norB gene product shares significant identity with the nitric oxide reductases inRalstonia eutropha and Synechocystis sp. and, like those organisms, the gonococcus lacks a norC homolog. The gonococcal norB gene was found to be required for anaerobic growth, but the absence of norB did not dramatically decrease anaerobic survival. In a wild-type background, induction of norB expression was seen anaerobically in the presence of nitrite but not anaerobically without nitrite or aerobically. norB expression is not regulated by FNR or NarP, but a functional aniA gene (which encodes an anaerobically induced outer membrane nitrite reductase) is necessary for expression. When aniA is constitutively expressed,norB expression can be induced both anaerobically and aerobically, but only in the presence of nitrite, suggesting that nitric oxide, which is likely to be produced by AniA as a product of nitrite reduction, is the inducing agent. This was confirmed with the use of the nitric oxide donor, spermine-nitric oxide complex, in ananiA null background both anaerobically and aerobically. NorB is important for gonococcal adaptation to an anaerobic environment, a physiologically relevant state during gonococcal infection. The presence of this enzyme, which is induced by nitric oxide, may also have implications in immune evasion and immunomodulation in the human host.


mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Egon A. Ozer ◽  
Lauren L. Prister ◽  
Shaohui Yin ◽  
Billy H. Ward ◽  
Stanimir Ivanov ◽  
...  

ABSTRACT Gene diversification is a common mechanism pathogens use to alter surface structures to aid in immune avoidance. Neisseria gonorrhoeae uses a gene conversion-based diversification system to alter the primary sequence of the gene encoding the major subunit of the pilus, pilE. Antigenic variation occurs when one of the nonexpressed 19 silent copies donates part of its DNA sequence to pilE. We have developed a method using Pacific Biosciences (PacBio) amplicon sequencing and custom software to determine pilin antigenic variation frequencies. The program analyzes 37 variable regions across the strain FA1090 1-81-S2 pilE gene and can be modified to determine sequence variation from other starting pilE sequences or other diversity generation systems. Using this method, we measured pilin antigenic variation frequencies for various derivatives of strain FA1090 and showed we can also analyze pilin antigenic variation frequencies during macrophage infection. IMPORTANCE Diversity generation systems are used by many unicellular organism to provide subpopulations of cell with different properties that are available when needed. We have developed a method using the PacBio DNA sequencing technology and a custom computer program to analyze the pilin antigenic variation system of the organism that is the sole cause of the sexually transmitted infection, gonorrhea.


FEBS Journal ◽  
2006 ◽  
Vol 274 (3) ◽  
pp. 677-686 ◽  
Author(s):  
João B. Vicente ◽  
Francesca M. Scandurra ◽  
João V. Rodrigues ◽  
Maurizio Brunori ◽  
Paolo Sarti ◽  
...  

Biochemistry ◽  
2001 ◽  
Vol 40 (44) ◽  
pp. 13361-13369 ◽  
Author(s):  
Janneke H. M. Hendriks ◽  
Louise Prior ◽  
Adam R. Baker ◽  
Andrew J. Thomson ◽  
Matti Saraste ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document