scholarly journals Isolation of the ARO1 cluster gene of Saccharomyces cerevisiae.

1983 ◽  
Vol 3 (9) ◽  
pp. 1609-1614 ◽  
Author(s):  
F W Larimer ◽  
C C Morse ◽  
A K Beck ◽  
K W Cole ◽  
F H Gaertner

The AROl cluster gene was isolated by complementation in Saccharomyces cerevisiae after transformation with a comprehensive yeast DNA library of BamHI restriction fragments inserted into the shuttle vector YEp13. Most of the transformants exhibited the expected episomal inheritance of the ARO+ phenotype; however, one stable transformant has been shown to be an integration of the AROl fragment and the vector YEp13 at the arol locus. The insert containing AROl is a 17.2-kilobase pair (kbp) BamHI fragment which complements both nonsense and missense alleles of arol. Subcloning by Sau3AI partial digestion further locates the AROl segment to a 6.2-kbp region. An autonomously replicating sequence (ars) was found on the 17.2-kbp fragment. Yeast arol mutants transformed with the AROl episome express 5 to 12 times the normal level of the five AROl enzyme activities and possess elevated amounts of the AROl protein. The yeast AROl fragment also complemented aroA, aroB, aroD, and aroE mutants of Escherichia coli. The expression of AROl in both S. cerevisiae and E. coli was independent of the orientation of the fragment with respect to the vector.

1983 ◽  
Vol 3 (9) ◽  
pp. 1609-1614
Author(s):  
F W Larimer ◽  
C C Morse ◽  
A K Beck ◽  
K W Cole ◽  
F H Gaertner

The AROl cluster gene was isolated by complementation in Saccharomyces cerevisiae after transformation with a comprehensive yeast DNA library of BamHI restriction fragments inserted into the shuttle vector YEp13. Most of the transformants exhibited the expected episomal inheritance of the ARO+ phenotype; however, one stable transformant has been shown to be an integration of the AROl fragment and the vector YEp13 at the arol locus. The insert containing AROl is a 17.2-kilobase pair (kbp) BamHI fragment which complements both nonsense and missense alleles of arol. Subcloning by Sau3AI partial digestion further locates the AROl segment to a 6.2-kbp region. An autonomously replicating sequence (ars) was found on the 17.2-kbp fragment. Yeast arol mutants transformed with the AROl episome express 5 to 12 times the normal level of the five AROl enzyme activities and possess elevated amounts of the AROl protein. The yeast AROl fragment also complemented aroA, aroB, aroD, and aroE mutants of Escherichia coli. The expression of AROl in both S. cerevisiae and E. coli was independent of the orientation of the fragment with respect to the vector.


1989 ◽  
Vol 35 (1) ◽  
pp. 164-170 ◽  
Author(s):  
Lawrence C. Shimmin ◽  
C. Hunter Newton ◽  
Celia Ramirez ◽  
Janet Yee ◽  
Willa Lee Downing ◽  
...  

Archaebacterial and eucaryotic cytoplasmic ribosomes contain proteins equivalent to the L11, L1, L10, and L12 proteins of the eubacterium Escherichia coli. In E. coli the genes encoding these ribosomal proteins are clustered, cotranscribed, and autogenously regulated at the level of mRNA translation. Genomic restriction fragments encoding the L11e, L1e, L10e, and L12e (equivalent) proteins from two divergent archaebacteria, Halobacterium cutirubrum and Sulfolobus solfataricus, and the L10e and L12e proteins from the eucaryote Saccharomyces cerevisiae have been cloned, sequenced, and analyzed. In the archaebacteria, as in eubacteria, the four genes are clustered and the L11e, L1e, L 10e, and L12e order is maintained. The transcription pattern of the H. cutirubrum cluster is different from the E. coli pattern and the flanking genes on either side of the tetragenic clusters in E. coli, H. cutirubrum, and Sulfolobus solfataricus are all unrelated to each other. In the eucaryote Saccharomyces cerevisiae there is a single L10e gene and four separate L12e genes that are designated L12eIA, L12eIB, L12eIIA, and L12eIIB. These five genes are not closely linked and each is transcribed as a monocistronic mRNA; the L10e, L12eIA, L12eIB, and the L12eIIA genes are contiguous and uninterrupted, whereas the L12eIIB gene is interrupted by a 301 nucleotide long intron located between codons 38 and 39.Key words: archaebacteria, ribosome, Halobacterium, Sulfolobus.


Genetics ◽  
1985 ◽  
Vol 109 (2) ◽  
pp. 303-332
Author(s):  
Jennifer A Jackson ◽  
Gerald R Fink

ABSTRACT We have studied the meiotic recombination behavior of strains carrying two types of duplications of an 18.6-kilobase HIS4 BamHI fragment. The first type is a direct duplication of the HIS4 BamHI fragment in which the repeated sequences are separated by Escherichia coli plasmid sequences. The second type, a tandem duplication, has no sequences intervening between the repeated yeast DNA. The HIS4 genes in each region were marked genetically so that recombination events between the duplicated segments could be identified. Meiotic progeny of the strains carrying the duplication were analyzed genetically and biochemically to determine the types of recombination events that had occurred. Analysis of the direct vs. tandem duplication suggests that the E. coli plasmid sequences are recombinogenic in yeast when homozygous. In both types of duplications recombination between the duplicated HIS4 regions occurs at high frequency and involves predominantly interchromosomal reciprocal exchanges (equal and unequal crossovers). The striking observation is that intrachromosomal reciprocal recombination is very rare in comparison with interchromosomal reciprocal recombination. However, intrachromosomal gene conversion occurs at about the same frequency as interchromosomal gene conversion. Reciprocal recombination events between regions on the same chromatid are the most infrequent exchanges. These data suggest that intrachromosomal reciprocal exchanges are suppressed.


1992 ◽  
Vol 282 (3) ◽  
pp. 747-752 ◽  
Author(s):  
O A M al-Bar ◽  
C D O'Connor ◽  
I G Giles ◽  
M Akhtar

A 1.2 kb BamHI fragment from pDK30 [Robinson, Kenan, Sweeney & Donachie (1986) J. Bacteriol. 167, 809-817] was cloned in pDOC55 [O'Connor & Timmis (1987) J. Bacteriol. 169, 4457-4482] to give two constructs, pDOC89 and pDOC87, in which the Escherichia coli D-alanine:D-alanine ligase (EC 6.3.2.4) gene (ddl) was placed under the control of the lac and lambda PL promoters respectively. Both constructs, when used to transform E. coli M72, gave similar levels of expression of the ddl gene. The expressed enzyme was purified to homogeneity and the amino acid sequence of its N-terminal region was found to be consistent with that predicted from the gene sequence, except that the N-terminal methionine was not present in the mature protein. [1(S)-Aminoethyl][(2RS)2-carboxy-1-octyl]phosphinic acid (I), previously shown to bind tightly to Enterococcus faecalis and Salmonella typhimurium D-alanine:D-alanine ligases following phosphorylation Parsons, Patchett, Bull, Schoen, Taub, Davidson, Combs, Springer, Gadebusch, Weissberger, Valiant, Mellin & Busch (1988) J. Med. Chem. 31, 1772-1778; Duncan & Walsh (1988) Biochemistry 27, 3709-3714], was found to be a classical slow-binding inhibitor of the E. coli ligase.


2000 ◽  
Vol 68 (3) ◽  
pp. 1400-1407 ◽  
Author(s):  
Phillip I. Tarr ◽  
Sima S. Bilge ◽  
James C. Vary ◽  
Srdjan Jelacic ◽  
Rebecca L. Habeeb ◽  
...  

ABSTRACT The mechanisms used by Shiga toxin (Stx)-producingEscherichia coli to adhere to epithelial cells are incompletely understood. Two cosmids from an E. coliO157:H7 DNA library contain an adherence-conferring chromosomal gene encoding a protein similar to iron-regulated gene A (IrgA) ofVibrio cholerae (M. B. Goldberg, S. A. Boyko, J. R. Butterton, J. A. Stoebner, S. M. Payne, and S. B. Calderwood, Mol. Microbiol. 6:2407–2418, 1992). We have termed the product of this gene the IrgA homologue adhesin (Iha), which is encoded by iha. Iha is 67 kDa in E. coliO157:H7 and 78 kDa in laboratory E. coli and is structurally unlike other known adhesins. DNA adjacent toiha contains tellurite resistance loci and is conserved in structure in distantly related pathogenic E. coli, but it is absent from nontoxigenic E. coli O55:H7, sorbitol-fermenting Stx-producing E. coli O157:H−, and laboratory E. coli. We have termed this region the tellurite resistance- and adherence-conferring island. We conclude that Iha is a novel bacterial adherence-conferring protein and is contained within an E. coli chromosomal island of conserved structure. Pathogenic E. coli O157:H7 has only recently acquired this island.


Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 40
Author(s):  
Mohd Kamuri ◽  
Zurina Zainal Abidin ◽  
Mohd Yaacob ◽  
Mohd Hamidon ◽  
Nurul Md Yunus ◽  
...  

This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2–24 s and a flow rate range of 1.2–9.6 μ L min − 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μ L min − 1 at a constant frequency, voltage, and a low conductivity.


1992 ◽  
Vol 38 (4) ◽  
pp. 350-353 ◽  
Author(s):  
A. Moreau ◽  
F. W. Paradis ◽  
R. Morosoli ◽  
F. Shareck ◽  
D. Kluepfel

This paper describes the construction and utilization of a novel shuttle vector for Streptomyces spp. and Escherichia coli as a useful vector in site-directed mutagenesis. The shuttle vector pIAFS20 (6.7 kb) has the following features: a replicon for Streptomyces spp., isolated from plasmid pIJ702; the thiostrepton-resistance gene as a selective marker in Streptomyces; the ColE1 origin, allowing replication in E. coli; and the ampicillin-resistance gene as a selective markerin E. coli. Vector pIAFS20 also contains the phage fl intergenic region, which permits production of single-stranded DNA in E. coli after superinfection with helper phage M13K07. Moreover, the lac promoter is located in front of the multiple cloning sites cassette, allowing eventual expression of the cloned genes in E. coli. After mutagenesis and screeningof the mutants in E. coli, the plasmids can be readily used to transform Streptomyces spp. As a demonstration, a 3.2-kb DNA fragment containing the gene encoding the xylanase A from Streptomyces lividans 1326 was inserted into pIAFS20, and the promoter region of this gene served as a target for site-directed mutagenesis. The two deletions reported here confirm the efficiency of this new vector as a tool in mutagenesis. Key words: shuttle vector, single-stranded DNA, site-directed mutagenesis, Streptomyces spp., Escherichia coli.


1997 ◽  
Vol 327 (3) ◽  
pp. 847-851 ◽  
Author(s):  
Zengji LI ◽  
Yue SUN ◽  
L. David THURLOW

Twenty-one RNA minihelices, resembling the coaxially stacked acceptor- /T-stems and T-loop found along the top of a tRNA's three-dimensional structure, were synthesized and used as substrates for ATP/CTP:tRNA nucleotidyltransferases from Escherichia coli and Saccharomyces cerevisiae. The sequence of nucleotides in the loop varied at positions corresponding to residues 56, 57 and 58 in the T-loop of a tRNA. All minihelices were substrates for both enzymes, and the identity of bases in the loop affected the interaction. In general, RNAs with purines in the loop were better substrates than those with pyrimidines, although no single base identity absolutely determined the effectiveness of the RNA as substrate. RNAs lacking bases near the 5ʹ-end were good substrates for the E. coli enzyme, but were poor substrates for that from yeast. The apparent Km values for selected minihelices were 2-3 times that for natural tRNA, and values for apparent Vmax were lowered 5-10-fold.


1985 ◽  
Vol 5 (4) ◽  
pp. 610-618 ◽  
Author(s):  
M F Hoekstra ◽  
R E Malone

The Escherichia coli DNA adenine methylase (dam) gene has been introduced into Saccharomyces cerevisiae on a yeast-E. coli shuttle vector. Sau3AI, MboI, and DpnI restriction enzyme digests and Southern hybridization analysis indicated that the dam gene is expressed in yeast cells and methylates GATC sequences. Analysis of digests of total genomic DNA indicated that some GATC sites are not sensitive to methylation. The failure to methylate may reflect an inaccessibility to the methylase due to chromosome structure. The effects of this in vivo methylation on the processes of recombination and mutation in mitotic cells were determined. A small but definite general increase was found in the frequency of mitotic recombination. A similar increase was observed for reversion of some auxotrophic markers; other markers demonstrated a small decrease in mutation frequency. The effects on mutation appear to be locus (or allele) specific. Recombination in meiotic cells was measured and was not detectably altered by the presence of 6-methyladenine in GATC sequences.


2001 ◽  
Vol 183 (21) ◽  
pp. 6253-6264 ◽  
Author(s):  
Jason Szeto ◽  
Sandra Ramirez-Arcos ◽  
Claude Raymond ◽  
Leslie D. Hicks ◽  
Cyril M. Kay ◽  
...  

ABSTRACT The Min proteins are involved in determining cell division sites in bacteria and have been studied extensively in rod-shaped bacteria. We have recently shown that the gram-negative coccus Neisseria gonorrhoeae contains a min operon, and the present study investigates the role of minD from this operon. A gonococcal minD insertional mutant, CJSD1, was constructed and exhibited both grossly abnormal cell division and morphology as well as altered cell viability. Western blot analysis verified the absence of MinD from N. gonorrhoeae(MinDNg) in this mutant. Hence, MinDNg is required for maintaining proper cell division and growth in N. gonorrhoeae. Immunoblotting of soluble and insoluble gonococcal cell fractions revealed that MinDNg is both cytosolic and associated with the insoluble membrane fraction. The joint overexpression of MinCNg and MinDNg from a shuttle vector resulted in a significant enlargement of gonococcal cells, while cells transformed with plasmids encoding either MinCNg or MinDNg alone did not display noticeable morphological changes. These studies suggest that MinDNg is involved in inhibiting gonococcal cell division, likely in conjunction with MinCNg. The alignment of MinD sequences from various bacteria showed that the proteins are highly conserved and share several regions of identity, including a conserved ATP-binding cassette. The overexpression of MinDNg in wild-type Escherichia coli led to cell filamentation, while overexpression in an E. coli minD mutant restored a wild-type morphology to the majority of cells; therefore, gonococcal MinD is functional across species. Yeast two-hybrid studies and gel-filtration and sedimentation equilibrium analyses of purified His-tagged MinDNg revealed a novel MinDNgself-interaction. We have also shown by yeast two-hybrid analysis that MinD from E. coli interacts with itself and with MinDNg. These results indicate that MinDNg is required for maintaining proper cell division and growth in N. gonorrhoeae and suggests that the self-interaction of MinD may be important for cell division site selection across species.


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