Nucleotide Clusters in Deoxyribonucleic Acids. VIII. The Pyrimidine Oligonucleotides of Bacteriophage S13 Wild Type DNA

1973 ◽  
Vol 51 (8) ◽  
pp. 1206-1211 ◽  
Author(s):  
John H. Spencer ◽  
Lynn Boshkov

A method for determination of the compositional assignment and comparison of the oligonucleotides in longer pyrimidine isostichs from closely related DNA's is described. The method is a dual 32P/33P labelling technique and has been used to investigate the pyrimidine oligonucleotide catalogue of bacteriophage S13 wild type DNA by comparison with the catalogue of the nitrous acid amber mutant S135suN15. The isomeric compositions of the dinucleotide CTp3 and trinucleotides CT2p4 and C2Tp4 from both DNA's were examined also. No cytosine (C) → thymine (T) transitions had occurred in the longer pyrimidine isostichs 7–11 inclusive, which constitute 10% of the catalogue of each of the two S13 DNA's, the catalogues of the two DNA's being indistinguishable.

2009 ◽  
Vol 64 (4) ◽  
pp. 786-793 ◽  
Author(s):  
T. Schon ◽  
P. Jureen ◽  
C. G. Giske ◽  
E. Chryssanthou ◽  
E. Sturegard ◽  
...  

2021 ◽  
Vol 22 (3) ◽  
pp. 1455
Author(s):  
Varsha Garg ◽  
Aleksandra Hackel ◽  
Christina Kühn

In potato plants, the phloem-mobile miR172 is involved in the sugar-dependent transmission of flower and tuber inducing signal transduction pathways and a clear link between solute transport and the induction of flowering and tuberization was demonstrated. The sucrose transporter StSUT4 seems to play an important role in the photoperiod-dependent triggering of both developmental processes, flowering and tuberization, and the phenotype of StSUT4-inhibited potato plants is reminiscent to miR172 overexpressing plants. The first aim of this study was the determination of the level of miR172 in sink and source leaves of StSUT4-silenced as well as StSUT4-overexpressing plants in comparison to Solanum tuberosum ssp. Andigena wild type plants. The second aim was to investigate the effect of sugars on the level of miRNA172 in whole cut leaves, as well as in whole in vitro plantlets that were supplemented with exogenous sugars. Experiments clearly show a sucrose-dependent induction of the level of mature miR172 in short time as well as long time experiments. A sucrose-dependent accumulation of miR172 was also measured in mature leaves of StSUT4-silenced plants where sucrose export is delayed and sucrose accumulates at the end of the light period.


1995 ◽  
Vol 52 (3) ◽  
pp. 548-554 ◽  
Author(s):  
V. Kava - Cordeiro ◽  
E.A. Luna - Alves - Lima ◽  
J.L. Azevedo

A wild strain of Metarhizium anisopliae, an entomopathogenic fungus, was submitted to three mutagenic agents: gamma radiation, ultraviolet light and nitrous acid. Survival curves were obtained and mutants were selected using different mutagenic doses which gave 1 to 5% survival. Morphological and auxotrophic mutants were isolated. Morphological mutants were grouped in a class with yellow conidia and other with pale vinaceous conidia as opposed to the green wild type conidia. Auxotrophic mutants had requirements for vitamin and aminoacid biosynthesis. More than 58% of the total auxotrophk mutants required proline/aipnine. Gamma radiation showed to be the most efficient mutagenic agent giving 0.2% of auxotrophk mutants followed by ultraviolet light (0.12%) and nitrous acid (0.06%).The conidial colour and auxotrophk mutants isolated until now from M. anisopliae were reviewed.


2003 ◽  
Vol 122 (3) ◽  
pp. 295-306 ◽  
Author(s):  
Sonia Traverso ◽  
Laura Elia ◽  
Michael Pusch

Opening of CLC chloride channels is coupled to the translocation of the permeant anion. From the recent structure determination of bacterial CLC proteins in the closed and open configuration, a glutamate residue was hypothesized to form part of the Cl−-sensitive gate. The negatively charged side-chain of the glutamate was suggested to occlude the permeation pathway in the closed state, while opening of a single protopore of the double-pore channel would reflect mainly a movement of this side-chain toward the extracellular pore vestibule, with little rearrangement of the rest of the channel. Here we show that mutating this critical residue (Glu166) in the prototype Torpedo CLC-0 to alanine, serine, or lysine leads to constitutively open channels, whereas a mutation to aspartate strongly slowed down opening. Furthermore, we investigated the interaction of the small organic channel blocker p-chlorophenoxy-acetic acid (CPA) with the mutants E166A and E166S. Both mutants were strongly inhibited by CPA at negative voltages with a >200-fold larger affinity than for wild-type CLC-0 (apparent KD at −140 mV ∼4 μM). A three-state linear model with an open state, a low-affinity and a high-affinity CPA-bound state can quantitatively describe steady-state and kinetic properties of the CPA block. The parameters of the model and additional mutagenesis suggest that the high-affinity CPA-bound state is similar to the closed configuration of the protopore gate of wild-type CLC-0. In the E166A mutant the glutamate side chain that occludes the permeation pathway is absent. Thus, if gating consists only in movement of this side-chain the mutant E166A should not be able to assume a closed conformation. It may thus be that fast gating in CLC-0 is more complex than anticipated from the bacterial structures.


1988 ◽  
Vol 256 (1) ◽  
pp. 213-218 ◽  
Author(s):  
P Wingfield ◽  
R Benedict ◽  
G Turcatti ◽  
B Allet ◽  
J J Mermod ◽  
...  

Human granulocyte colony-stimulating factor (G-CSF), and a mutant having a Ser for Cys substitution at residue 18 were produced in Escherichia coli strain W3110. About 60 mg of pure protein was obtained from 50 g of wet cells with a recovery of about 20%. The proteins were characterized physically and chemically, including determination of disulphide bonds, which were found to exist between residues 37-43 and 65-75. Cys-18 is not involved in disulphide bond formation and was substituted by Ser with no effects on gross protein conformation or biological activity. Both the wild-type and the mutant recombinant-derived proteins, although not glycosylated, possess colony-stimulating activities. In a bioassay using the murine myelomonocytic leukaemic cell line WEH1 3B D+, activities were obtained which were similar to those of natural G-CSF and of a glycosylated recombinant-derived human G-CSF produced in monkey cells.


Immunobiology ◽  
2006 ◽  
Vol 211 (6-8) ◽  
pp. 449-453 ◽  
Author(s):  
Elisabeth Zinser ◽  
Matthias Lechmann ◽  
Antje Golka ◽  
Barry Hock ◽  
Alexander Steinkasserer

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Karin Meinike Jørgensen ◽  
Karen M. T. Astvad ◽  
Rasmus Krøger Hare ◽  
Maiken Cavling Arendrup

ABSTRACT Olorofim is a novel antifungal agent with in vitro activity against Aspergillus and some other molds. Here, we addressed technical aspects for EUCAST olorofim testing and generated contemporary MIC data. EUCAST E.Def 9.3.1 testing was performed comparing two plate preparation methods (serial dilution in medium [serial plates] versus predilution in DMSO [ISO plates]), two lots of olorofim, visual (visual-MIC) versus spectrophotometer (spec-MIC) reading, and four polystyrene plates using 34 to 53 Aspergillus isolates from five genera. Subsequently, olorofim MICs were compared to itraconazole, voriconazole, posaconazole, and amphotericin B MICs for 298 clinical mold isolates (2016 to 2017). Wild-type upper limits (WT-UL) were determined following EUCAST principles for epidemiologic cutoff value (ECOFF) setting. Olorofim median MICs comparing serial plates and ISO plates were identical (25/36 [69%]) or one dilution apart (11/36 [31%]). Interperson agreement for visual-MICs was 92% to 94%/100% for ≤1/≤2 dilutions, respectively. The visual-MIC values across tested microtiter plates and olorofim lots revealed only discrete differences (≤1 dilution lower for treated plates). No single spec-MIC criterion was applicable to all species. Olorofim MICs were low against 275 Aspergillus species isolates (modal MIC, 0.06 mg/liter; MIC range, < 0.004 to 0.25 mg/liter) and three dermatophytes (MICs 0.03 to 0.06 mg/liter). MICs against Fusarium were diverse, with full inhibition of F. proliferatum (MIC, 0.016), 50% growth inhibition of Fusarium solani at 1 to 2 mg/liter, and no inhibition of F. dimerum. Olorofim displayed potent in vitro activity against most mold isolates and was associated with limited variation in EUCAST susceptibility testing.


2000 ◽  
Vol 203 (6) ◽  
pp. 1059-1070 ◽  
Author(s):  
U. Nagel ◽  
H. Machemer

Wild-type and the morphological mutant kin 241 of Paramecium tetraurelia showed improved orientation away from the centre of gravity (negative gravitaxis) when accelerations were increased from 1 to 7 g. Gravitaxis was more pronounced in the mutant. A correlation between the efficiency of orientation and the applied g value suggests a physical basis for gravitaxis. Transiently enhanced rates of reversal of the swimming direction coincided with transiently enhanced gravitaxis because reversals occurred more often in downward swimmers than in upward swimmers. The results provide evidence of a physiological modulation of gravitaxis by means of the randomizing effect of depolarization-dependent swimming reversals. Gravity bimodally altered propulsion rates of wild-type P. tetraurelia so that sedimentation was partly antagonized in upward and downward swimmers (negative gravikinesis). In the mutant, only increases in propulsion were observed, although the orientation-dependent sensitivity of the gravikinetic response was the same as in the wild-type population. Observed swimming speed and sedimentation rates in the wild-type and mutant cells were linearly related to acceleration, allowing the determination of gravikinesis as a linear (and so far non-saturating) function of gravity.


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