Nitrate reductase electron transport systems in mutant and in wild-type strains of neurospora

Author(s):  
George J. Sorger
1991 ◽  
Vol 46 (7-8) ◽  
pp. 703-705 ◽  
Author(s):  
Astrid Witt ◽  
Jobst-Heinrich Klemme

Patterns of endogenous plasmids and nitrate reductase activities were analyzed in the phototrophic bacterium Rhodobacter (Rb.) capsulatus. From 10 strains investigated (including a UV-induced plasmidless nit- mutant), 4 were unable to grow photosynthetically with nitrate as N-source and lacked nitrate reductase activity (nit strains). Irrespective of the nit phenotype, all wildtype strains contained at least one large plasmid with a size ranging from 93 to 134 kb. Thus, other than in plasmid- cured mutants (J. C. Willison, FEMS Microbiol. Lett. 66, 23-28[1990]), in wild-type strains of Rb. capsulatus the nit- character was not related to lack of endogenous plasmids.


Author(s):  
Hanrong Wang ◽  
Youran Li ◽  
Fengxu Xiao ◽  
Yupeng Zhang ◽  
Guiyang Shi ◽  
...  

Amino acid efflux and influx transport systems play vital roles in industrial microorganisms’ cell growth and metabolism. However, although biochemically characterized, most amino acid transporters remain unknown at the molecular level in Bacillus licheniformis. This study focuses on the molecular and functional characterizations of three transporters, YdgF, YvbW, and YveA, mainly when catalyzing the cross-membrane flux of L-Aspartate. When growing in the minimal medium with L-Asp as the only carbon and nitrogen source, the growth of strains lacking proteins YdgF, YvbW, and YveA was significantly inhibited compared with wild-type strains, while supplementing the expression of the corresponding proteins in the single-gene knockout strains can alleviate the inhibition to some extent. Upon overexpression, the recombinant proteins mediate the accumulation of L-aspartate to varying degrees. Compared with wild-type strains, the single knockout strains of the three protein genes exhibited reduced absorption of L-aspartate. In addition, this paper focuses on the effects of these three proteins on the absorption of β-alanine, L-glutamate, D-serine, D-alanine, and glycine.


Fermentation ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 22
Author(s):  
Hanrong Wang ◽  
Youran Li ◽  
Fengxu Xiao ◽  
Yupeng Zhang ◽  
Guiyang Shi ◽  
...  

Amino acid efflux and influx transport systems play vital roles in industrial microorganisms’ cell growth and metabolism. However, although biochemically characterized, most of them remain unknown at the molecular level in Bacillus licheniformis. In this study, three proteins, namely, YdgF, YvbW, and YveA, were predicted to be involved in the active transport of L-aspartate (L-Asp). This was verified by manipulating their encoding genes. When growing in the minimal medium with L-Asp as the only carbon and nitrogen source, the growth of strains lacking proteins YdgF, YvbW, and YveA was significantly inhibited compared with the wild-type strains, while supplementing the expression of the corresponding proteins in the single-gene knockout strains could alleviate the inhibition. Upon overexpression, the recombinant proteins mediated the accumulation of L-aspartate to varying degrees. Compared with the wild-type strains, the single knockout strains of the three protein genes exhibited reduced absorption of L-aspartate. In addition, this study focused on the effects of these three proteins on the absorption of β-alanine, L-glutamate, D-serine, D-alanine, and glycine.


Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 89-101 ◽  
Author(s):  
Qijun Xiang ◽  
N Louise Glass

AbstractA non-self-recognition system called vegetative incompatibility is ubiquitous in filamentous fungi and is genetically regulated by het loci. Different fungal individuals are unable to form viable heterokaryons if they differ in allelic specificity at a het locus. To identify components of vegetative incompatibility mediated by allelic differences at the het-c locus of Neurospora crassa, we isolated mutants that suppressed phenotypic aspects of het-c vegetative incompatibility. Three deletion mutants were identified; the deletions overlapped each other in an ORF named vib-1 (vegetative incompatibility blocked). Mutations in vib-1 fully relieved growth inhibition and repression of conidiation conferred by het-c vegetative incompatibility and significantly reduced hyphal compartmentation and death rates. The vib-1 mutants displayed a profuse conidiation pattern, suggesting that VIB-1 is a regulator of conidiation. VIB-1 shares a region of similarity to PHOG, a possible phosphate nonrepressible acid phosphatase in Aspergillus nidulans. Native gel analysis of wild-type strains and vib-1 mutants indicated that vib-1 is not the structural gene for nonrepressible acid phosphatase, but rather may regulate nonrepressible acid phosphatase activity.


Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 71-81
Author(s):  
Eric Espagne ◽  
Pascale Balhadère ◽  
Marie-Louise Penin ◽  
Christian Barreau ◽  
Béatrice Turcq

Abstract Vegetative incompatibility, which is very common in filamentous fungi, prevents a viable heterokaryotic cell from being formed by the fusion of filaments from two different wild-type strains. Such incompatibility is always the consequence of at least one genetic difference in specific genes (het genes). In Podospora anserina, alleles of the het-e and het-d loci control heterokaryon viability through genetic interactions with alleles of the unlinked het-c locus. The het-d2Y gene was isolated and shown to have strong similarity with the previously described het-e1A gene. Like the HET-E protein, the HET-D putative protein displayed a GTP-binding domain and seemed to require a minimal number of 11 WD40 repeats to be active in incompatibility. Apart from incompatibility specificity, no other function could be identified by disrupting the het-d gene. Sequence comparison of different het-e alleles suggested that het-e specificity is determined by the sequence of the WD40 repeat domain. In particular, the amino acids present on the upper face of the predicted β-propeller structure defined by this domain may confer the incompatible interaction specificity.


1992 ◽  
Vol 12 (9) ◽  
pp. 3827-3833 ◽  
Author(s):  
T H Adams ◽  
W A Hide ◽  
L N Yager ◽  
B N Lee

In contrast to many other cases in microbial development, Aspergillus nidulans conidiophore production initiates primarily as a programmed part of the life cycle rather than as a response to nutrient deprivation. Mutations in the acoD locus result in "fluffy" colonies that appear to grow faster than the wild type and proliferate as undifferentiated masses of vegetative cells. We show that unlike wild-type strains, acoD deletion mutants are unable to make conidiophores under optimal growth conditions but can be induced to conidiate when growth is nutritionally limited. The requirement for acoD in conidiophore development occurs prior to activation of brlA, a primary regulator of development. The acoD transcript is present both in vegetative hyphae prior to developmental induction and in developing cultures. However, the effects of acoD mutations are detectable only after developmental induction. We propose that acoD activity is primarily controlled at the posttranscriptional level and that it is required to direct developmentally specific changes that bring about growth inhibition and activation of brlA expression to result in conidiophore development.


Genetics ◽  
1996 ◽  
Vol 142 (3) ◽  
pp. 761-776 ◽  
Author(s):  
Lori A Rinckel ◽  
David J Garfinkel

Abstract In Saccharomyces cerevisiae, the target site specificity of the retrotransposon Ty1 appears to involve the Ty integration complex recognizing chromatin structures. To determine whether changes in chromatin structure affect Ty1 and Ty2 target site preference, we analyzed Ty transposition at the CAN1 locus in mutants containing altered levels of histone proteins. A Δhta1-htb1 mutant with decreased levels of H2A and H2B histone proteins showed a pattern of Ty1 and Ty2 insertions at CAN1 that was significantly different from that of both the wild-type and a Δhta2-htb2 mutant, which does not have altered histone protein levels. Altered levels of H2A and H2B proteins disrupted a dramatic orientation bias in the CAN1 promoter region. In the wild-type strains, few Ty1 and Ty2 insertions in the promoter region were oriented opposite to the direction of CAN1 transcription. In the Δhta1-htb1 background, however, numerous Ty1 and Ty2 insertions were in the opposite orientation clustered within the TATA region. This altered insertion pattern does not appear to be due to a bias caused by selecting canavanine resistant isolates in the different HTA1-HTB1 backgrounds. Our results suggest that reduced levels of histone proteins alter Ty target site preference and disrupt an asymmetric Ty insertion pattern.


Sign in / Sign up

Export Citation Format

Share Document