(1) The majority of overproduced NIFA and NIFL was insoluble after low-speed centrifugation and was inactive in vitro.
(2) Binding of NifA to the upstream activator sequence (UAS) of the nifH promoter in the presence of the NifL protein was observed under nitrogen-limiting growth conditions.
(3) Complementation analysis of millimicron-induced, amber, frameshift, and deletion mutations indicates there are five polycistronic and two monocistronic operons: nifQ nifB, nifA nifL, nifF, nifM nifV nifS, nifN nifE, nifK nifD nifH, and nifJ.
(4) The nifL protein (a repressor) was coded by an open reading frame of 1,485 bases, corresponding to a protein of 495 amino acids with a calculated molecular weight of 55,242.
(5) Sequences located between -227 and -158 with respect to the nifL transcription start site are required for efficient activation of the nifLA promoter in vitro.
(6) Not all base changes produced similar strong promoter down phenotypes when the nifL and nifH promoters were compared: activation of the nifH promoter by the nifA gene product was less sensitive to base changes in conserved nucleotides than was activation of the equivalently altered nifL promoter by the nifA or ntrC products.
(7) The residual activity is particularly sensitive to inhibition by NifL, suggesting that the role of the N-terminal domain is to block the action of NifL in derepressing conditions.
(8) The activity of NIFA was dramatically reduced in vitro in the presence of the negative regulatory protein NIFL (nifL gene product) but was not inhibited by the presence of a mutant NIFL protein, NIFL2404.
(9) The gene upstream of nifA is therefore designated nifL because of its similarity to the Klebsiella pneumoniae nifL gene in proximity to nifA, in mutant phenotype, and in amino acid sequence of the gene product.
(10) PII is not involved in the nif-specific response to changes in nitrogen status mediated by NifL.
(11) However, the nifL product was not required for the cessation of synthesis of these transcripts at elevated temperatures.
(12) However, the mutant protein retains the ability to increase the occupancy of the -24, -12 region by sigma 54-RNA polymerase, forming closed complexes at the nifL promoter, which are not detectable in the absence of NTRC.
(13) Only two mutants, RK383 and RH383, are active in promoting transcription from either the glnAp2 promoter or the nifL promoter.
(14) Transcription from the sigma 54-dependent Klebsiella pneumoniae nifL and glnAp2 promoters is activated by the general nitrogen regulatory protein NTRC.
(15) These regulatory effects required the nifL product.
(16) The initiation codon (ATG) of nifA overlapped the termination codon(TGA) of nifL, sharing the two bases T and G. A conserved DNA contact point [Gln-(X)3-Ala-(X)3-Gly-(X)5-Val] common in many DNA binding proteins was found in the C-terminal region of the nifA sequence.
(17) The influence of the Klebsiella pneumoniae nifL gene product upon the interaction of the transcriptional activator protein NifA with the nifH promoter has been examined using in vivo dimethylsulphate 'footprinting'.
(18) In NifL- strains, both forms of analysis indicated that the nifL product was involved in nif mRNA destabilization in the presence of O2 and NH4+.
(19) At the wild-type nifL promoter, sigma 54-RNA polymerase makes only limited contacts with the promoter in the absence of NTRC.
(20) Formation of open complexes at glnAp2 peaks at -0.024 and declines at higher superhelical densities, whereas at the wild-type nifL promoter, open complex formation peaks at -0.067 and is not detectable at superhelical densities less than -0.032.
Trifle
Definition:
(n.) A thing of very little value or importance; a paltry, or trivial, affair.
(n.) A dish composed of sweetmeats, fruits, cake, wine, etc., with syllabub poured over it.
(n.) To act or talk without seriousness, gravity, weight, or dignity; to act or talk with levity; to indulge in light or trivial amusements.
(v. t.) To make of no importance; to treat as a trifle.
(v. t.) To spend in vanity; to fritter away; to waste; as, to trifle away money.
Example Sentences:
(1) After a relatively trifling lead exposure they developed the signs of acute lead intoxication.
(2) It featured Adam Dalgliesh, the poet-policeman, and he seemed old-fashioned, too, intellectual and a trifle upper-class.
(3) So Inter sold him to Real Madrid at the end of the 1995-96 season for the trifling sum of £3.5million - less than they had paid for him.
(4) 1.15pm: Dave Espley is not a man to be trifled with: "I'd agree with Steven Gardner regarding the use of video technology for goalline reviews, but I'd go slightly further with regard to the retrospective punishment for cheating.
(5) Clementine and dark chocolate trifle (above) This recipe gives classic trifle a zingy twist with clementines and orange blossom; a great make-ahead dinner party dessert.
(6) Of course it is the hyperbolic silliness – the make-or-break trifle sponge, custard thefts, and prolonged ruminations over "The Crumb" – that makes The Great British Bake Off so lovable.
(7) English friends had explained to me, not without pride, the importance of grumbling to the national character, but I still want to stress to every Londoner I meet that — take it from a visiting Los Angeleno — the tube exists, and that counts as no trifling achievement.
(8) But it is a trifle dispiriting even so to hear the education secretary parroting the same lines as his predecessors – even more so for teachers, I guess.
(9) This March, the proportions of loans taken by finance and property slumped all the way to a trifling 74.7%, while non-financial firms took a whopping 25.3%.
(10) It wasn't a baked Alaska, a fruit tart, a cream-laden trifle or a steamed treacle sponge.
(11) If you wish to have only a trifling risk group of 10% of all pregnant women, you can predict right only about 50% of all infants with low birth weight.
(12) Bake Off validates the small quiet dramas of the trifling everyday.
(13) As in most mutinous them-and-us industrial confrontations it had been simmering for years and then boiled over for what seemed the most trifling of reasons.
(14) "And he is at a loss whether to pity a people who take such arrant trifles in good earnest or to envy that happiness which enables a community to discuss them."
(15) I try to answer these letters, but compared to the stories I'm hearing, my experience has been trifling - as more than one correspondent has pointed out.
(16) With the menswear shows in the capital now on their sixth season, such trifles have their place even in the mainstream world of an Arcadia-owned brand.
(17) Some jokey conspiracy theories did the rounds and one YouTube user criticised Hadfield's interpretation of the song as being overly literal (arguably correct, but a trifle harsh, considering).
(18) Clegg was the deputy prime minister and would not jeopardise his relationship with the Conservative party over such a trifle.
(19) And what would become of my mornings in my little corner and my late nights scanning the TV channels, watching my crime shows, not a trifling thing?
(20) But it’s no trifle — especially given the governor’s national ambitions.