Structural requirements of DNA used in the Farr assay to detect antibodies directed against double-stranded DNA

1987 ◽  
Vol 7 (4) ◽  
pp. 161-168
Author(s):  
K. M. Pollard ◽  
J. Webb
1979 ◽  
Vol 25 (3) ◽  
pp. 366-370 ◽  
Author(s):  
A O Vladutiu ◽  
D A Palumbo ◽  
J E Asirwatham

Abstract Antinuclear antibodies are almost always found in sera of patients with systemic lupus erythematosus. To differentiate antinuclear antibodies from antibodies to DNA in the recently described Crithidia luciliae assay, we developed an immunoperoxidase technique for detecting antibodies to native, double-stranded DNA and compared results by it with those by the Farr assay. Smears of cultured Crithidia luciliae were incubated with human sera, peroxidase-labeled anti-human IgG serum, and diaminobenzidine. The peroxidase stain was examined by conventional light microscopy, which facilitated differentiation between the kinetoplast and the nuclear staining. The Crithidia assay appeared to be specific for double-stranded DNA antibodies, seemed to be more sensitive than the Farr assay, and allowed us to determine the immunoglobulin classes of antibodies to native DNA. Some patients with systemic lupus erythematosus had only IgM or IgA antibodies to DNA.


1979 ◽  
Vol 9 (4) ◽  
pp. 243-251 ◽  
Author(s):  
FRANÇOIS COUTURE ◽  
ANDRÉ BEAULIEU ◽  
LEDA RAPTIS ◽  
HENRI-ANDRÉ MÉNARD

Author(s):  
George C. Ruben ◽  
Kenneth A. Marx

In vitro collapse of DNA by trivalent cations like spermidine produces torus (donut) shaped DNA structures thought to have a DNA organization similar to certain double stranded DNA bacteriophage and viruses. This has prompted our studies of these structures using freeze-etch low Pt-C metal (9Å) replica TEM. With a variety of DNAs the TEM and biochemical data support a circumferential DNA winding model for hydrated DNA torus organization. Since toruses are almost invariably oriented nearly horizontal to the ice surface one of the most accessible parameters of a torus population is annulus (ring) thickness. We have tabulated this parameter for populations of both nicked, circular (Fig. 1: n=63) and linear (n=40: data not shown) ϕX-174 DNA toruses. In both cases, as can be noted in Fig. 1, there appears to be a compact grouping of toruses possessing smaller dimensions separated from a dispersed population possessing considerably larger dimensions.


Author(s):  
Ray Wu ◽  
G. Ruben ◽  
B. Siegel ◽  
P. Spielman ◽  
E. Jay

A method for determining long nucleotide sequences of double-stranded DNA is being developed. It involves (a) the synchronous digestion of the DNA from the 3' ends with EL coli exonuclease III (Exo III) followed by (b) resynthesis with labeled nucleotides and DNA polymerase. A crucial factor in the success of this method is the degree to which the enzyme digestion proceeds synchronously under proper conditions of incubation (step a). Dark field EM is used to obtain accurate measurements on the lengths and distribution of the DNA molecules before and after digestion with Exo III, while gel electrophoresis is used in parallel to obtain a mean length for these molecules. It is the measurements on a large enough sample of individual molecules by EM that provides the information on how synchronously the digestion proceeds. For length measurements, the DNA molecules were picked up on 20-30 Å thick carbon-aluminum films, using the aqueous Kleinschmidt technique and stained with 7.5 x 10-5M uranyl acetate in 90% ethanol for 3 minutes.


Author(s):  
George C. Ruben ◽  
Kenneth A. Marx

Certain double stranded DNA bacteriophage and viruses are thought to have their DNA organized into large torus shaped structures. Morphologically, these poorly understood biological DNA tertiary structures resemble spermidine-condensed DNA complexes formed in vitro in the total absence of other macromolecules normally synthesized by the pathogens for the purpose of their own DNA packaging. Therefore, we have studied the tertiary structure of these self-assembling torus shaped spermidine- DNA complexes in a series of reports. Using freeze-etch, low Pt-C metal (10-15Å) replicas, we have visualized the microscopic DNA organization of both calf Thymus( CT) and linear 0X-174 RFII DNA toruses. In these structures DNA is circumferentially wound, continuously, around the torus into a semi-crystalline, hexagonal packed array of parallel DNA helix sections.


2020 ◽  
Vol 7 (2) ◽  
pp. 272-282
Author(s):  
Vadim Viktorovich Dementyev

The transformation of scientific genres in the context of the general digitalization of modern culture is considered. It is shown that the speech genre content of this process is based on the mechanisms of generation and transformation of the text of two types, the interpretation of which can be useful in order to better understand the nature, tasks and tools of scientometry at this stage, and in order to better understand the speech genre structure of scientific speech. Firstly, the structural requirements for articles and monographs indexed in scientometric systems (Scopus, WoS, DOAJ, RSCI, etc.) are approved and streamlined, and thereby our knowledge of what an article is from its structure (i.e. knowledge about the genre of the article). Secondly, the requirements of indexing systems lead to the fact that the texts of articles change, they are “written differently”, and sometimes redone after appropriate recommendations from publishers. The points highlighted in scientometric systems can be understood as signs that an article must comply with in order to be assigned to the “speech genre of a scientific article”. The largest quantitative indicators for these items are indicators of how close to the core of the genre this or that text will turn out.


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