MUTANTS OF THE BIOLOGICAL CLOCK IN CHLAMYDOMONAS REINHARDI

ABSTRACT A genetic analysis of the biological clock in Chlamydomonas reinhardi has been initiated. Of six wild-type strains tested (3 mt+ and 3 mt−), five had periods close to 24 hr whereas one had a 21-hr period. Mutants with altered clock period have been isolated. The periods of 3 of these variant strains are temperature compensated. Genetic crosses involving a long-period mutant suggest that a single gene confers the long-period character, and in general clock-period length seems to be a useful phenotypic measure of alterations in the clock due to genetic differences. One phase mutant was found but its behavior was variable and the phase of the rhythm, relative to a light–dark transition which initiates the rhythm, does not seem to be reliable as a parameter of clock differences. No markers have yet been mapped.

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RECOMBINANTS BETWEEN CLOCK MUTANTS OF CHLAMYDOMONAS REINHARDI

Genetics ◽

10.1093/genetics/77.2.221 ◽

1974 ◽

Vol 77 (2) ◽

pp. 221-229

Author(s):

Victor G Bruce

Keyword(s):

Biological Clock ◽

Period Length ◽

Wild Type ◽

Long Period ◽

Normal Period ◽

Period Lengthening ◽

Mutant Genes

ABSTRACT Mutants affecting the period length of the biological clock in Chlamydomonas reinhardi have been isolated and a start has been made on analyzing the genetics of this system. In four mutants, the long period characteristic seems to be controlled by single genes at separate loci. Crosses between single mutants, as well as crosses involving three or four mutant genes, yielded progeny with periods characteristic of the parents as well as recombinant types, including normal period (wild type) and extra-long periods (double, triple and quadruple mutants). It was found that the period lengthening effect is additive; that is, the period of double mutants is lengthened by the sum of the period lengthening of the single mutants.

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Genetic Analysis of the Sinorhizobium meliloti BacA Protein: Differential Effects of Mutations on Phenotypes

Journal of Bacteriology ◽

10.1128/jb.183.21.6444-6453.2001 ◽

2001 ◽

Vol 183 (21) ◽

pp. 6444-6453 ◽

Cited By ~ 42

Author(s):

Kristin LeVier ◽

Graham C. Walker

Keyword(s):

Amino Acids ◽

Genetic Analysis ◽

Protein Function ◽

Sinorhizobium Meliloti ◽

Null Allele ◽

Biological Function ◽

Wild Type ◽

Phenotypic Characteristics ◽

Multiple Phenotypes ◽

Type Strains

ABSTRACT Sinorhizobium meliloti strains lacking BacA function are impaired in symbiosis with alfalfa host plants and display altered sensitivities to a number of compounds relative to wild-type strains. With the goal of finding clues to the currently unknown biological function(s) of BacA, we carried out a genetic analysis to determine which amino acids are critical for protein function and to attempt to ascertain whether the multiple phenotypes that result from abacA-null allele were the result of a common cause or whether BacA has multiple functions. We have created a set of 20 site-directed mutants in which selected individual amino acids inbacA were replaced with glycine residues. The resulting mutants were characterized to determine how the various amino acid changes affected a number of phenotypes associated with loss of BacA function. Mutants H165G, W182G, D198G, and R284G had null phenotypes for all functions assayed, while mutants W57G, S83G, S231G, and K350G were indistinguishable from wild-type strains. The remaining 12 site-directed mutants demonstrate mixed phenotypic characteristics and fall into a number of distinctly different groups. These observations may be consistent with a role for BacA in multiple, nonoverlapping functions.

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ISOGENIC STRAINS OF PHYCOMYCES BLAKESLEEANUS SUITABLE FOR GENETIC ANALYSIS

Genetics ◽

10.1093/genetics/105.4.873 ◽

1983 ◽

Vol 105 (4) ◽

pp. 873-879

Author(s):

M I Alvarez ◽

A P Eslava

Keyword(s):

Genetic Analysis ◽

Mating Type ◽

Type Strain ◽

Wild Type ◽

Tetrad Analysis ◽

Phycomyces Blakesleeanus ◽

Isogenic Strains ◽

Type Strains

ABSTRACT The progeny of crosses between wild-type strains of Phycomyces usually do not exhibit all of the expected genotypes from meiosis. By backcrossing, we have isolated a new (+) mating-type strain, A56, which is nearly isogenic with the (-) wild-type NRRL1555 commonly used in Phycomyces research. Tetrad analysis of the backcrosses shows that meiosis becomes more regular as the parental (+) and (-) strains become more isogenic. In our two-factor crosses with unlinked markers, the regularity of meiosis is measured as the percent of reciprocal ditypes plus tetratypes in the progeny. We have shown that this percentage increases from about 15% for crosses between nonisogenic parents to 90% in the eighth backcross. The results indicate that routine, reliable recombination analyses are possible in P. blakesleeanus.

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GENETIC ANALYSIS OF GAMMA-RAY MUTAGENESIS IN YEAST. I. REVERSION IN RADIATION-SENSITIVE STRAINS

Genetics ◽

10.1093/genetics/93.2.361 ◽

1979 ◽

Vol 93 (2) ◽

pp. 361-373

Author(s):

Richard H McKee ◽

Christopher W Lawrence

Keyword(s):

Ionizing Radiation ◽

Genetic Analysis ◽

Gamma Ray ◽

Wild Type ◽

Uv Mutagenesis ◽

Major Pathway ◽

Gene Functions ◽

Γ Rays ◽

Γ Ray ◽

Type Strains

ABSTRACT The frequency of revertants induced by 6OCo γ rays of the ochre allele, cyc1-9, has been measured in radiation-sensitive strains carrying one of 19 nonallelic mutations and in wild-type strains. The results indicate that ionizing radiation mutagenesis depends on the activity of the RAD6 group of genes and that the gene functions employed are very similar, but probably not identical, to those that mediate UV mutagenesis. Repair activities dependent on the functions of the RAD50 through RAD57 loci, the major pathway for the repair of damage caused by ionizing radiation, do not appear to play any part in mutagenesis. A comparison between the γ-ray data and those obtained previously with UV (LAWRENCE and CHRISTENSEN 1976) and chemical mutagens (PRAKASH 1976) suggests that the RAD6 "mutagenic pathway" is in fact composed of a set of processes, some of which are concerned with error-prone, and some with error-free, recovery activities.

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Functional Characterization of Transporters for L-Aspartate in Bacillus licheniformis

10.20944/preprints202111.0304.v1 ◽

2021 ◽

Author(s):

Hanrong Wang ◽

Youran Li ◽

Fengxu Xiao ◽

Yupeng Zhang ◽

Guiyang Shi ◽

...

Keyword(s):

Amino Acid ◽

Bacillus Licheniformis ◽

Gene Knockout ◽

Single Gene ◽

Functional Characterization ◽

Transport Systems ◽

Amino Acid Transporters ◽

Wild Type ◽

Beta Alanine ◽

Type Strains

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.

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Genetic studies inEudorina

Genetics Research ◽

10.1017/s0016672300011162 ◽

1968 ◽

Vol 11 (1) ◽

pp. 21-31 ◽

Cited By ~ 10

Author(s):

Nawin C. Mishra ◽

S. F. H. Threlkeld

Keyword(s):

Genetic Analysis ◽

Mating Type ◽

Single Gene ◽

Female Parent ◽

Cross Resistance ◽

Nutritional Requirement ◽

Wild Type ◽

Type Locus ◽

S 100 ◽

High Concentrations

A formal genetic analysis of the heterothallic, colonial green algaEudorina eleganshas been described. Wild-type strains were found to be sensitive to different drugs when grown on minimal agar containing very low concentrations of these drugs. Mutant strains resistant to high concentrations of drugs have been isolated. These aremsr-500(resistant to 500 μg/ml of DL-methionine-DL-sulfoximine),ery-r-100(resistant to 100 μg/ml of erythromycin) andsr-100(resistant to 100 μg/ml of streptomycin). The wild-type phenotypes sensitive to these drugs have been designated asmss-500,ery-s-100andss-100respectively. Thesr-100also showed cross-resistance to other antibiotics belonging to the streptomycin group.On genetic analysis, themsr-500andery-s-100were found to be inherited in a Mendelian way. These alleles are not linked to each other or to the mating type locus. The inheritance of mating type was found to be due to a single gene difference.The inheritance ofss-100/sr-100was found to be non-chromosomal and was characteristically uniparental, always transmitted through the female parent. The evidence for the non-chromosomal gene (NC genes) controllingsr-100/ss-100phenotypes in this organism has been derived from the exceptional zygotes in which the male parent apparently transmits streptomycin resistance to the progeny. Although ultraviolet or gamma-radiation resulted in normal survival curves of the exposed cells, no mutant deficient in any nutritional requirement was isolated.

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Functional Characterization of Transporters for L-Aspartate in Bacillus licheniformis

Fermentation ◽

10.3390/fermentation8010022 ◽

2022 ◽

Vol 8 (1) ◽

pp. 22

Author(s):

Hanrong Wang ◽

Youran Li ◽

Fengxu Xiao ◽

Yupeng Zhang ◽

Guiyang Shi ◽

...

Keyword(s):

Bacillus Licheniformis ◽

Gene Knockout ◽

Single Gene ◽

Functional Characterization ◽

Transport Systems ◽

Wild Type ◽

Carbon And Nitrogen ◽

Influx Transport ◽

Amino Acid Efflux ◽

Type Strains

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.

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Resistance to amino acid analogues in Coprinus: Dominance modifier genes and dominance reversal in dikaryons and diploids

Genetics Research ◽

10.1017/s0016672300015500 ◽

1975 ◽

Vol 25 (2) ◽

pp. 95-107 ◽

Cited By ~ 6

Author(s):

S. Senathirajah ◽

D. Lewis

Keyword(s):

Carboxylic Acid ◽

Single Gene ◽

Modifier Genes ◽

Wild Type ◽

Recessive Resistance ◽

Amino Acid Analogues ◽

Resistant Mutants ◽

Selection For ◽

Oligomeric Product ◽

Type Strains

SUMMARYWild-type strains of Coprinus lagopus are sensitive to para-fluoro-phenylalanine and ethionine. Resistant mutants to these two analogues are known but all these mutants are recessive in a heterozygous dikaryon except for F7 (pfpr-3) which is semi-dominant. Resistance to two other analogues, however – canavanine sulphate and azetidine-2-carboxylic acid – were found to be wild-type features. One strain of C. lagopus sensitive to canavanine was identified. Selection for canavanine resistance in monokaryons always yielded only dominant resistance, while selection for para-fluorophenylalanine resistance in monokaryons gave only recessive resistance. Canavanine-resistant mutants were due to a single gene mutation which, like the wild-type resistance, were dominant in heterozygous dikaryons. The wild-type resistance was also dominant in a diploid but the mutant resistance was recessive. Selection for resistance to para-fluorophenylalanine in auxotrophically balanced dikaryons resulted in the identification of two new loci (pfpr-10 and pfpr-ll), and two specific dominance modifiers (mod+-10 and mod+-ll). In the absence of the specific modifier, pfpr-10 and pfpr-ll were recessive while, in the presence of even one dose of the specific modifier, resistance was dominant in the dikaryon. The pfpr-10 and pfpr-ll even in the presence of two doses of modifier were fully recessive in the diploid. The action of the modifier genes and the reversal of dominance in dikaryon and diploid is discussed in terms of negative complementation in an oligomeric product of the pfpr gene and localized translation of the relevant mRNA in the cell with the modifier acting as a reinforcer of localization.

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Subtle Impact of Akt1 and Akt3 on Exploratory Behavior in Gene Targeted Mice

Zeitschrift für Psychologie ◽

10.1027/2151-2604/a000218 ◽

2015 ◽

Vol 223 (3) ◽

pp. 173-180 ◽

Cited By ~ 1

Author(s):

Christina Leibrock ◽

Michael Hierlmeier ◽

Undine E. Lang ◽

Florian Lang

Keyword(s):

Forced Swimming Test ◽

Open Field Test ◽

Wild Type ◽

Average Speed ◽

Closed Area ◽

Light Area ◽

Swimming Test ◽

The Impact ◽

Center Area ◽

Dark Transition

Abstract. The present study explored the impact of Akt1 and Akt3 on behavior. Akt1 (akt1-/-) and Akt3 (akt3-/-) knockout mice were compared to wild type (wt) mice. The akt1-/- mice, akt3-/- mice, and wt mice were similar in most parameters of the open-field test. However, the distance traveled in the center area was slightly but significantly less in akt3-/- mice than in wt mice. In the light/dark transition test akt1-/- mice had significantly lower values than wt mice and akt3-/- mice for distance traveled, number of rearings, rearing time in the light area, as well as time spent and distance traveled in the entrance area. They were significantly different from akt3-/- mice in the distance traveled, visits, number of rearings, rearing time in the light area, as well as time spent, distance traveled, number of rearings, and rearing time in the entrance area. In the O-maze the time spent, and the visits to open arms, as well as the number of protected and unprotected headdips were significantly less in akt1-/- mice than in wt mice, whereas the time spent in closed arms was significantly more in akt1-/- mice than in wt mice. Protected and unprotected headdips were significantly less in akt3-/- mice than in wt mice. In closed area, akt3-/- mice traveled a significantly larger distance at larger average speed than akt1-/- mice. No differences were observed between akt1-/- mice, akt3-/- mice and wt-type mice in the time of floating during the forced swimming test. In conclusion, akt1-/- mice and less so akt3-/ mice display subtle changes in behavior.

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Functional expression of a yeast mitochondrial intron-encoded protein requires RNA processing at a conserved dodecamer sequence at the 3' end of the gene.

Molecular and Cellular Biology ◽

10.1128/mcb.9.4.1507 ◽

1989 ◽

Vol 9 (4) ◽

pp. 1507-1512 ◽

Cited By ~ 22

Author(s):

H Zhu ◽

H Conrad-Webb ◽

X S Liao ◽

P S Perlman ◽

R A Butow

Keyword(s):

Genetic Analysis ◽

Rna Processing ◽

Fold Increase ◽

Functional Expression ◽

Rrna Gene ◽

Yeast Mitochondria ◽

Wild Type ◽

Site Specific ◽

Var1 Gene ◽

A Site

All mRNAs of yeast mitochondria are processed at their 3' ends within a conserved dodecamer sequence, 5'-AAUAAUAUUCUU-3'. A dominant nuclear suppressor, SUV3-I, was previously isolated because it suppresses a dodecamer deletion at the 3' end of the var1 gene. We have tested the effects of SUV3-1 on a mutant containing two adjacent transversions within a dodecamer at the 3' end of fit1, a gene located within the 1,143-base-pair intron of the 21S rRNA gene, whose product is a site-specific endonuclease required in crosses for the quantitative transmission of that intron to 21S alleles that lack it. The fit1 dodecamer mutations blocked both intron transmission and dodecamer cleavage, neither of which was suppressed by SUV3-1 when present in heterozygous or homozygous configurations. Unexpectedly, we found that SUV3-1 completely blocked cleavage of the wild-type fit1 dodecamer and, in SUV3-1 homozygous crosses, intron conversion. In addition, SUV3-1 resulted in at least a 40-fold increase in the amount of excised intron accumulated. Genetic analysis showed that these phenotypes resulted from the same mutation. We conclude that cleavage of a wild-type dodecamer sequence at the 3' end of the fit1 gene is essential for fit1 expression.

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