scholarly journals Deactivation of the autotrophic sulfate assimilation pathway substantially reduces high-level β-lactam antibiotic biosynthesis and arthrospore formation in a production strain from Acremonium chrysogenum

Microbiology ◽  
2017 ◽  
Vol 163 (6) ◽  
pp. 817-828 ◽  
Author(s):  
Dominik Terfehr ◽  
Ulrich Kück
Keyword(s):  
Antibiotic Biosynthesis ◽  
Acremonium Chrysogenum ◽  
Sulfate Assimilation ◽  
Sulfate Assimilation Pathway ◽  
Lactam Antibiotic ◽  
High Level ◽  
Production Strain

Experimental Prediction of the Evolution of Cefepime Resistance From the CMY-2 AmpC β-Lactamase

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 23-29
Author(s):  
Miriam Barlow ◽  
Barry G Hall
Keyword(s):  
Good Predictor ◽  
Evolutionary Potential ◽  
Biochemical Activity ◽  
Class A ◽  
Naturally Occurring ◽  
Experimental Prediction ◽  
Lactam Antibiotic ◽  
High Level ◽  
Level Resistance

Abstract Understanding of the evolutionary histories of many genes has not yet allowed us to predict the evolutionary potential of those genes. Intuition suggests that current biochemical activity of gene products should be a good predictor of the potential to evolve related activities; however, we have little evidence to support that intuition. Here we use our in vitro evolution method to evaluate biochemical activity as a predictor of future evolutionary potential. Neither the class C Citrobacter freundii CMY-2 AmpC β-lactamase nor the class A TEM-1 β-lactamase confer resistance to the β-lactam antibiotic cefepime, nor do any of the naturally occurring alleles descended from them. However, the CMY-2 AmpC enzyme and some alleles descended from TEM-1 confer high-level resistance to the structurally similar ceftazidime. On the basis of the comparison of TEM-1 and CMY-2, we asked whether biochemical activity is a good predictor of the evolutionary potential of an enzyme. If it is, then CMY-2 should be more able than the TEMs to evolve the ability to confer higher levels of cefepime resistance. Although we generated CMY-2 evolvants that conferred increased cefepime resistance, we did not recover any CMY-2 evolvants that conferred resistance levels as high as the best cefepime-resistant TEM alleles.

scholarly journals The Recovery from Sulfur Starvation is Independent from the mRNA Degradation Initiation Enzyme PARN in Arabidopsis

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 380 ◽  
Author(s):  
Armbruster ◽  
Uslu ◽  
Wirtz ◽  
Hell
Keyword(s):  
Stress Responses ◽  
Splice Variants ◽  
Marker Genes ◽  
Sulfate Assimilation ◽  
Sulfur Deficiency ◽  
Protective Measures ◽  
Sulfur Starvation ◽  
Sulfate Assimilation Pathway ◽  
Growth Promoting

When plants are exposed to sulfur limitation, they upregulate the sulfate assimilation pathway at the expense of growth-promoting measures. Upon cessation of the stress, however, protective measures are deactivated, and growth is restored. In accordance with these findings, transcripts of sulfur-deficiency marker genes are rapidly degraded when starved plants are resupplied with sulfur. Yet it remains unclear which enzymes are responsible for the degradation of transcripts during the recovery from starvation. In eukaryotes, mRNA decay is often initiated by the cleavage of poly(A) tails via deadenylases. As mutations in the poly(A) ribonuclease PARN have been linked to altered abiotic stress responses in Arabidopsis thaliana, we investigated the role of PARN in the recovery from sulfur starvation. Despite the presence of putative PARN-recruiting AU-rich elements in sulfur-responsive transcripts, sulfur-depleted PARN hypomorphic mutants were able to reset their transcriptome to pre-starvation conditions just as readily as wildtype plants. Currently, the subcellular localization of PARN is disputed, with studies reporting both nuclear and cytosolic localization. We detected PARN in cytoplasmic speckles and reconciled the diverging views in literature by identifying two PARN splice variants whose predicted localization is in agreement with those observations.

scholarly journals Global Regulation of the Response to Sulfur Availability in the Cheese-Related BacteriumBrevibacterium aurantiacum

2010 ◽  
Vol 77 (4) ◽  
pp. 1449-1459 ◽  
Author(s):  
Marie-Pierre Forquin ◽  
Agnès Hébert ◽  
Aurélie Roux ◽  
Julie Aubert ◽  
Caroline Proux ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Sulfur Metabolism ◽  
Metabolic Reconstruction ◽  
Sulfate Assimilation ◽  
Sulfur Starvation ◽  
Expression Of Genes ◽  
Transsulfuration Pathway ◽  
Sulfate Assimilation Pathway ◽  
Genes Encoding ◽  
Sulfur Containing

ABSTRACTIn this study, we combined metabolic reconstruction, growth assays, and metabolome and transcriptome analyses to obtain a global view of the sulfur metabolic network and of the response to sulfur availability inBrevibacterium aurantiacum. In agreement with the growth ofB. aurantiacumin the presence of sulfate and cystine, the metabolic reconstruction showed the presence of a sulfate assimilation pathway, thiolation pathways that produce cysteine (cysEandcysK) or homocysteine (metXandmetY) from sulfide, at least one gene of the transsulfuration pathway (aecD), and genes encoding three MetE-type methionine synthases. We also compared the expression profiles ofB. aurantiacumATCC 9175 during sulfur starvation or in the presence of sulfate. Under sulfur starvation, 690 genes, including 21 genes involved in sulfur metabolism and 29 genes encoding amino acids and peptide transporters, were differentially expressed. We also investigated changes in pools of sulfur-containing metabolites and in expression profiles after growth in the presence of sulfate, cystine, or methionine plus cystine. The expression of genes involved in sulfate assimilation and cysteine synthesis was repressed in the presence of cystine, whereas the expression ofmetX,metY,metE1,metE2, andBL613, encoding a probable cystathionine-γ-synthase, decreased in the presence of methionine. We identified three ABC transporters: two operons encoding transporters were transcribed more strongly during cysteine limitation, and one was transcribed more strongly during methionine depletion. Finally, the expression of genes encoding a methionine γ-lyase (BL929) and a methionine transporter (metPS) was induced in the presence of methionine in conjunction with a significant increase in volatile sulfur compound production.

scholarly journals Host Cell–Induced Components of the Sulfate Assimilation Pathway Are Major Protective Antigens of Mycobacterium tuberculosis

2012 ◽  
Vol 207 (5) ◽  
pp. 778-785 ◽  
Author(s):  
Rachel Pinto ◽  
Lisa Leotta ◽  
Erin R. Shanahan ◽  
Nicholas P. West ◽  
Thomas S. Leyh ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Host Cell ◽  
Sulfate Assimilation ◽  
Protective Antigens ◽  
Sulfate Assimilation Pathway
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