Die Sichtbarmachung von pflanzlichem Virus im �bermikroskop

Kausche, G. A.; Pfankuch, E.; Rüska, H.

doi:10.1007/bf01493353

Cited by 220 publications

(60 citation statements)

References 16 publications

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“…The conclusion of this study is that the virus preparations consist of approximately cylindrical particles about 150 A in diameter. Their length cannot easily be estimated by x-ray methods, but the minimum value of 1,500 A found by Kausche, Pfankuch, and Ruska (1939) is compatible with the x-ray evidence. Much longer partides formed by aggregation of these also occur.…”

Section: Biological Significancesupporting

confidence: 68%

X-Ray and Crystallographic Studies of Plant Virus Preparations. Iii

Bernal

Fankuchen

1941

Journal of General Physiology

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These papers give an account of an optical and x-ray examination of preparations of plant virus substances isolated by Bawden and Pirie, in particular of those of tobacco mosaic disease. They open with a historical survey of the work, indicating the order in which new phenomena were discovered. The subsequent treatment is divided into three parts: I. Introduction and preparation of specimens. II. Modes of aggregation of virus particles. III. (1) The structure of the particles. (2) Biological implications. Part I, after an historical introduction, describes the method of preparation, from solutions of the virus, of optically oriented specimens of different concentrations. For their examination special x-ray apparatus was developed, in particular cameras working with very low angles and capable of indicating spacings up to 1000 Å. In Part III, Section 1 deals with the x-ray evidence on the internal structure of the particles. Even in solution, they have an inner regularity like that of a crystal. Virus preparations are thus in a sense doubly crystalline. Closer analysis reveals that the x-ray patterns are not directly comparable to those of a crystal as many of the reflections do not obey Bragg's law, but can be understood on the theory of gratings of limited size. The structure seems to consist of sub-units of the dimensions of approximately 11 Å cube, fitted together in a hexagonal or pseudohexagonal lattice of dimensions—a = 87 Å, c = 68 Å. Contrary to what earlier observations seemed to indicate, the particle seems to be virtually unchanged by drying and must therefore contain little water. There are marked resemblances with the structure of both crystalline and fibrous protein, but the virus structure does not belong to any of the classes hitherto studied. There are indications that the inner structure is of a simpler character than that of the molecules of crystalline proteins. Part III, Section 2 contains a comparative study of the optical and x-ray examinations of three strains of tobacco mosaic virus, two of cucumber disease virus, two of potato virus X, and the virus of bushy stunt disease of tomato. In the last case x-ray measurement confirmed the deduction from its cubic crystal habit that it was composed of spherical rather than long particles, and showed that these had a diameter when dry of 276 Å and were arranged in a body-centred cubic close packing. This single example is sufficient to show that the elongated particle form which gives rise to all the anomalous physical properties of the other viruses studied is of no essential biological importance. The similarity and differences observed between the physical properties of these preparations run closely parallel to their clinical and serological classification. Finally, the biological implications of these results are discussed together with possible applications of the new methods of examination to the study of colloid and biological problems.

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Section: Biological Significancesupporting

confidence: 68%

X-Ray and Crystallographic Studies of Plant Virus Preparations. Iii

Bernal

Fankuchen

1941

Journal of General Physiology

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“…Even some 10 years after the original description of the tobacco mosaic virus as a long thin rod (5) there is some discussion as to whether these particles represent individual units (6) or aggregates of virus (7). It is not legitimate to accept any spherical particle obtained from a mixture of materials as virus just because it has a size which agrees with previous calculations and because it is frequently found in these partially purified preparations.…”

Section: (From the Department Of Animal And Plant Pathology Of The Romentioning

confidence: 99%

Studies on Newcastle Disease Virus

Bang¹

1948

Journal of Experimental Medicine

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1. It is likely that certain tailed and filamentous particles seen on electron microscope examination of partially purified saline suspensions of Newcastle virus are the individual virus particles because: (a) They have a highly characteristic shape not seen in other virus preparations. (b) They are present whenever the virus is present in high concentration. (c) Their size agrees with the size of the virus as calculated from light scattering and centrifuge data. (d) They are agglutinated by specific antisera. (e) Infection may be produced in the embryo by relatively few of these particles. 2. It is possible that these filamentous forms have been derived from spherical forms without loss of activity because: (a) Such filamentous forms are not found in the original allantoic fluid when this contains a comparable amount of virus. (b) Filamentous forms appeared in the original allantoic fluid when it was dialyzed against saline solution. (c) Filamentous forms were produced at certain hydrogen ion concentrations but not at others, in solutions maintaining the same infectivity for the embryo. (d) Spherical forms were obtained by suspending the partially purified virus in water instead of saline. In this the virus remained moderately stable. (e) These round forms could apparently be converted into tailed and filamentous forms by the addition of saline, again without loss of activity. (f) This "conversion" could be inhibited by partial inactivation of the water suspension of virus.

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“…Virology 1798-Jenner develops vaccination for smallpox (115) 1885-Pasteur develops and uses rabies vaccine (116) 1892-Ivanofsky shows TMV is caused by filterable agent (13) 1909-Poliovirus discovered (117) 1915-d'Herelle develops Plaque Assay (17) 1939-1st photographs of viruses with electron microscope (18) 1948-1955-Transition to cell culture for virus propagation and vaccine production (19,20) 1952-Salk develops Polio vaccine (118) 1970-Reverse transcriptase discovered (119) 1981-1st infectious clone of a virus (120) 1985-1st 3D structure of a virus (121) 1842-Long performs surgery under ether anesthesia (111) 1895-Radiotherapy for cancer (6) 1903-1st cured case of cervical cancer by X-rays (6) 1942-Nitrogen mustards introduced as chemotherapeutics (112) 1948-Folic acid antagonists for treatment of leukemia (8) 1958-1st solid tumor cured by chemotherapy (113) 1965-Simultaneous administration of drugs (POMP regimen) induces long term remission in ALL (114) 1968-Stereotactic radio surgery developed (5) 2005-1st approved oncolytic virus (3) History of Oncolytic Viruses infectious diseases known to be of viral etiology at that time, there was no real concept of the nature of a virus. The "discovery" of viruses is difficult to pinpoint.…”

Section: Cancer Therapymentioning

confidence: 99%

“…16 Biochemical analysis of viruses proceeded apace, but it was not until the advent of the plaque assay in 1917 that their particulate nature could be proven, 17 and electron microscopic images of viral particles were not obtained until 1939. 18 The first half of the twentieth century was something of a dark age for virology. Although agents that could pass through filters had been implicated in many diseases (e.g., polio, rabies, influenza), their precise identity was still unclear.…”

Section: Cancer Therapymentioning

confidence: 99%

History of Oncolytic Viruses: Genesis to Genetic Engineering

2007

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Since the turn of the nineteenth century, when their existence was first recognized, viruses have attracted considerable interest as possible agents of tumor destruction. Early case reports emphasized regression of cancers during naturally acquired virus infections, providing the basis for clinical trials where body fluids containing human or animal viruses were used to transmit infections to cancer patients. Most often the viruses were arrested by the host immune system and failed to impact tumor growth, but sometimes, in immunosuppressed patients, infection persisted and tumors regressed, although morbidity as a result of the infection of normal tissues was unacceptable. With the advent of rodent models and new methods for virus propagation, there were numerous attempts through the 1950s and 1960s to force the evolution of viruses with greater tumor specificity, but success was limited and many researchers abandoned the field. Technology employing reverse genetics later brought about a renewal of interest in virotherapy that allowed the generation of more potent, tumor-specific oncolytics. Here, examination of early oncolytic virotherapy before genetic engineering serves to highlight tremendous advances, yet also hints at ways to penetrate host immune defenses, a significant remaining challenge in modern virotherapy research.

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Die Sichtbarmachung von pflanzlichem Virus im �bermikroskop

Cited by 220 publications

References 16 publications

X-Ray and Crystallographic Studies of Plant Virus Preparations. Iii

X-Ray and Crystallographic Studies of Plant Virus Preparations. Iii

Studies on Newcastle Disease Virus

History of Oncolytic Viruses: Genesis to Genetic Engineering

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