Transformation of restriction endonuclease phenotype in Streptococcus pneumoniae

1982 ◽  
Vol 152 (1) ◽  
pp. 183-190
Author(s):  
C C Muckerman ◽  
S S Springhorn ◽  
B Greenberg ◽  
S A Lacks
Keyword(s):  
Streptococcus Pneumoniae ◽  
Restriction Endonuclease ◽  
Genetic Basis ◽  
Laboratory Strain ◽  
The Other ◽  
Unique Restriction ◽  
Different Strains ◽  
Spontaneous Conversion

The genetic basis of the unique restriction endonuclease DpnI, that cleaves only at a methylated sequence, 5'-GmeATC-3', and of the complementary endonuclease DpnII, which cleaves at the same sequence when it is not methylated, was investigated. Different strains of Streptococcus pneumoniae isolated from patients contained either DpnI (two isolates) or DpnII (six isolates). The latter strains also contained DNA methylated at the 5'-GATC-3' sequence. A restrictable bacteriophage, HB-3, was used to characterize the various strains and to select for transformants. One laboratory strain contained neither DpnI nor Dpn II. It was probably derived from a DpnI-containing strain, and its DNA was not methylated at 5'-GATC-3'. Cells of this strain were transformed to the DpnI restriction phenotype by DNA from a DpnI-containing strain and to the DpnII restriction phenotype by DNA from a DpnII-containing strain. Neither cross-transformation, that is, transformation to one phenotype by DNA from a strain of the other phenotype, nor spontaneous conversion was observed. Extracts of transformants to the new restriction phenotype were shown to contain the corresponding endonuclease.

Toxicity of malathion to the natural enemies of California red scale, Aonidiella aurantii (Mask.) (Hemiptera: Diaspididae)

1973 ◽  
Vol 24 (1) ◽  
pp. 119 ◽  
Author(s):  
I Abdelrahman
Keyword(s):  
Body Weight ◽  
Surface Area ◽  
Natural Enemies ◽  
Laboratory Strain ◽  
The Body ◽  
The Other ◽  
Aonidiella Aurantii ◽  
Males And Females ◽  
Different Strains

The lethality of malathion to all stages of red scale of three different strains was tested. Scales from areas subjected to spraying were 1.87 times as tolerant as those from unsprayed areas, which in turn were 1.52 times as tolerant as the laboratory strain. Of the seven distinguishable stages of red scale only the first moult (males and females), second moult females, and young-producing females proved to be significantly more tolerant than the other stages, the second moult female being three times as tolerant as the young-producing female, or nine times as tolerant if the body weight and surface area are taken into account. The latter finding is important, because it has been customary to estimate the efficiency of spray treatments by mortality in the young-producing stage. This would leave many of the second moult females alive after spraying and the infestation would continue.

scholarly journals RIBONUCLEASE ACTIVITY OF PERIPHERAL LEUCOCYTES AND SERUM IN RABIES-SUSCEPTIBLE AND RABIES-REFRACTORY MICE

1965 ◽  
Vol 13 (6) ◽  
pp. 515-517 ◽  
Author(s):  
J. B. ENRIGHT ◽  
F. L. FRYE ◽  
O. S. ATWAL
Keyword(s):  
Rabies Virus ◽  
Genetic Basis ◽  
Comparative Data ◽  
The Other ◽  
Ribonuclease Activity ◽  
Host Susceptibility ◽  
Enzyme Localization ◽  
Extracellular Level ◽  
Different Strains ◽  
Susceptibility And Resistance

Comparative data are presented on the intra- and extracellular concentrations of blood ribonuclease in two different strains of mice; one rabies-susceptible, the other rabies-refractory. The coincidence of finding a higher extracellular level of the enzyme in the rabies-refractory group is discussed in its possible relationship to mechanisms of host susceptibility and resistance to virulent rabies virus. The probable genetic basis for the differences in enzyme localization is also discussed.

Mechanism of sulfonamide resistance in clinical isolates of Streptococcus pneumoniae.

1997 ◽  
Vol 41 (10) ◽  
pp. 2121-2126 ◽  
Author(s):  
J P Maskell ◽  
A M Sefton ◽  
L M Hall
Keyword(s):  
Streptococcus Pneumoniae ◽  
Genetic Basis ◽  
Laboratory Strain ◽  
Clinical Isolates ◽  
Gene Exchange ◽  
Gene Encoding ◽  
Dihydropteroate Synthase ◽  
Loss Of Resistance ◽  
Sulfonamide Resistance

The genetic basis of sulfonamide resistance in six clinical isolates of Streptococcus pneumoniae was demonstrated to be 3- or 6-bp duplications within sulA, the chromosomal gene encoding dihydropteroate synthase. The duplications all result in repetition of one or two amino acids in the region from Arg58 to Tyr63, close to but distinct from the sul-d mutation, a duplication previously reported in a resistant laboratory strain (P. Lopez, M. Espinosa, B. Greenberg, and S. A. Lacks, J. Bacteriol. 169:4320-4326, 1987). Six sulfonamide-susceptible clinical isolates lacked such duplications. The role of the duplications in conferring sulfonamide resistance was confirmed by transforming 319- or 322-bp PCR fragments into the chromosome of a susceptible recipient. Two members of a clone of serotype 9V, one susceptible and one resistant to sulfonamide, which are highly related by other criteria, were shown to have sulA sequences that differ in 7.2% of nucleotides in addition to the duplication responsible for resistance. It is postulated that horizontal gene exchange has been involved in the acquisition (or loss) of resistance within this clone. However, five of the six resistant isolates have distinct duplications and other sequence polymorphisms, suggesting that resistance has arisen independently on many occasions.

scholarly journals Epistatic Control of Non-Mendelian Inheritance in Mouse Interspecific Crosses

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1739-1752 ◽  
Author(s):  
Xavier Montagutelli ◽  
Rowena Turner ◽  
Joseph H Nadeau
Keyword(s):  
X Chromosome ◽  
Genetic Basis ◽  
Mendelian Inheritance ◽  
The Other ◽  
Interspecific Crosses ◽  
Chromosome 2 ◽  
Mus Spretus ◽  
F1 Hybrid ◽  
Strong Deviation ◽  
Marker Loci

Abstract Strong deviation of allele frequencies from Mendelian inheritance favoring Mus spretus-derived alleles has been described previously for X-linked loci in four mouse interspecific crosses. We reanalyzed data for three of these crosses focusing on the location of the gene(s) controlling deviation on the X chromosome and the genetic basis for incomplete deviation. At least two loci control deviation on the X chromosome, one near Xist (the candidate gene controlling X inactivation) and the other more centromerically located. In all three crosses, strong epistasis was found between loci near Xist and marker loci on the central portion of chromosome 2. The mechanism for this deviation from Mendelian expectations is not yet known but it is probably based on lethality of embryos carrying particular combinations of alleles rather than true segregation distortion during oogenesis in F1 hybrid females.

scholarly journals Interactions of the Streptococcus pneumoniae Toxin-Antitoxin RelBE Proteins with Their Target DNA

2021 ◽  
Vol 9 (4) ◽  
pp. 851
Author(s):  
Inmaculada Moreno-Córdoba ◽  
Wai-Ting Chan ◽  
Concha Nieto ◽  
Manuel Espinosa
Keyword(s):  
Streptococcus Pneumoniae ◽  
Self Regulation ◽  
Mrna Translation ◽  
Dna Supercoiling ◽  
Bacterial Toxin ◽  
Type Ii ◽  
Cellular Functions ◽  
Dna Backbone ◽  
Different Strains ◽  
Palindromic Sequences

Type II bacterial toxin-antitoxin (TA) systems are found in most bacteria, archaea, and mobile genetic elements. TAs are usually found as a bi-cistronic operon composed of an unstable antitoxin and a stable toxin that targets crucial cellular functions like DNA supercoiling, cell-wall synthesis or mRNA translation. The type II RelBE system encoded by the pathogen Streptococcus pneumoniae is highly conserved among different strains and participates in biofilm formation and response to oxidative stress. Here, we have analyzed the participation of the RelB antitoxin and the RelB:RelE protein complex in the self-regulation of the pneumococcal relBE operon. RelB acted as a weak repressor, whereas RelE performed the role of a co-repressor. By DNA footprinting experiments, we show that the proteins bind to a region that encompasses two palindromic sequences that are located around the −10 sequences of the single promoter that directs the synthesis of the relBE mRNA. High-resolution footprinting assays showed the distribution of bases whose deoxyriboses are protected by the bound proteins, demonstrating that RelB and RelB:RelE contacted the DNA backbone on one face of the DNA helix and that these interactions extended beyond the palindromic sequences. Our findings suggest that the binding of the RelBE proteins to its DNA target would lead to direct inhibition of the binding of the host RNA polymerase to the relBE promoter.

Effects of three azole derivatives on the lipids of different strains ofSporothrix schenckii

1997 ◽  
Vol 43 (12) ◽  
pp. 1197-1202 ◽  
Author(s):  
Agnes Kiesling Casali ◽  
Júnia Soares Hamdan
Keyword(s):  
Inhibitory Concentration ◽  
Sporothrix Schenckii ◽  
The Other ◽  
Ergosterol Biosynthesis ◽  
Complete Agreement ◽  
Sterol Content ◽  
Ultraviolet Spectrophotometry ◽  
Different Strains ◽  
Layer Chromatography ◽  
Azole Derivative

The comparative effects of ketoconazole, itraconazole, and fluconazole on the lipids of five Sporothrix schenckii strains were investigated. Quantitative analysis of lipids and sterols was completed, as well as qualitative analysis of sterols, by thin-layer chromatography and ultraviolet spectrophotometry. Growth of the S. schenckii isolates in the presence of azole derivative concentrations below the minimum inhibitory concentration (MIC) resulted in significant alterations in the lipid and sterol contents as compared with the control values. Furthermore, lanosterol was detected in these azole-treated cells. These results were in complete agreement with the proposed mechanism of action of azoles, which act by inhibiting ergosterol biosynthesis with a consequent accumulation of lanosterol. Concerning the MIC values, fluconazole was found to be the least effective drug. On the other hand, as determined from a comparison of the effects of the three azoles on the sterol content of the strains studied, no significant differences in efficacy were found among the tested drugs.Key words: Sporothrix schenckii, azole derivatives, lipids, sterols.

scholarly journals Mutations in Transglutaminase 1 Gene in Autosomal Recessive Congenital Ichthyosis in Egyptian Families

2004 ◽  
Vol 20 (6) ◽  
pp. 325-332 ◽  
Author(s):  
R. M. Shawky ◽  
N.S. Sayed ◽  
N.A. Elhawary
Keyword(s):  
Restriction Endonuclease ◽  
Splice Site ◽  
Autosomal Recessive ◽  
Splice Mutation ◽  
The Other ◽  
Splice Acceptor ◽  
Acceptor Splice Site ◽  
Congenital Ichthyosis ◽  
Transglutaminase 1 ◽  
Autosomal Recessive Congenital Ichthyosis

Autosomal recessive congenital ichthyosis (ARCI) is a rare heterogeneous keratinization disorder of the skin. It is clinically divided into 2 subtypes, lamellar ichthyosis (LI) and congenital ichthyosiformis erythroderma (CIE). We investigated forty-three ARCI Egyptian individuals in 16 severe LI, and 10 CIE families. We identified 5 alleles in two Egyptian families as having intron-5/exon-6 splice acceptor mutation recognized by theMspIrestriction endonuclease. This promoted to a frequency of 9.6% for this mutation (5 splice-mutation alleles/52 alleles tested). We extended our previous dataset to update the detection of R142H mutation in 4 CIE Egyptian families and one LI phenotype (frequency of 28.8%; 15/52), whereas we still had no R141H among our Egyptian population. There was no correlation between phenotype and genotype in our study. Surprisingly, the mutant alleles detected in intron-5 acceptor splice-site were associated with the other extreme of CIE phenotypes rather than the severe LI form. We clearly demonstrated that the ARCI Egyptian families in Upper Egypt was ethnically pure and had a tendency not to be a hybrid with other populations in Lower Egypt, Delta zone and Cairo city.

Purification and characterization of exocellular proteases produced by a clinical isolate and a laboratory strain of Pseudomonas aeruginosa

1980 ◽  
Vol 26 (1) ◽  
pp. 77-86 ◽  
Author(s):  
S. E. Jensen ◽  
L. Phillippe ◽  
J. Teng Tseng ◽  
G. W. Stemke ◽  
J. N. Campbell
Keyword(s):  
Molecular Weight ◽  
Pseudomonas Aeruginosa ◽  
Clinical Isolate ◽  
Protease Activity ◽  
Gel Filtration ◽  
Laboratory Strain ◽  
Exchange Chromatography ◽  
The Other ◽  
Protease Production ◽  
Peptide Bonds

Exocellular protease production was examined in two separate strains of Pseudomonas aeruginosa, one a clinical isolate and the other a laboratory strain. Both strains produced two separate proteases (proteases 1 and 2) which were indistinguishable from one strain to the other. The two proteases were purified by a two-step procedure of gel filtration chromatography followed by ion-exchange chromatography. Proteases 1 and 2 were shown to be distinct serologically and unrelated by physicochemical parameters examined. Protease 1 was the major exocellular protein produced and contributed about 95% of the total protease activity of the culture. It was estimated to have a molecular weight of 34 850 and was also shown to contain 10% glucosamine by weight. Protease 2, in contrast, had an estimated molecular weight of 52750 and contained no detectable carbohydrate. Proteases 1 and 2 were both stimulated by Ca2+, and Mg2+ and inhibited by Co2+Zn2+, and 1,10-o-phenanthroline. Protease 1 was also inhibited by EDTA. In addition to protease activity, both proteases 1 and 2 demonstrated elastase activity as well as a limited collagenase activity. Specificity of the two proteases against synthetic peptides was, however, quite different. Protease 1, but not protease 2, showed a preference for peptide bonds in which the amino group was contributed by an amino acid with a hydrophobic R group.

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