Failure to demonstrate in vitro as opposed to in vivo transcription of the bluetongue virus genome

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Obituary: Dr Max Sterne

This volume of the journal is dedicated to Max Sterne in recognition of his contributions to veterinary bacteriology.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

History of orbivirus research in South Africa

In the early colonial history of South Africa, horses played an important role, both in general transportation and in military operations. Frequent epidemics of African horsesickness (AHS) in the 18th century therefore severely affected the economy. The first scientific research on the disease was carried out by Alexander Edington (1892), the first government bacteriologist of the Cape Colony, who resolved the existing confusion that reigned and established its identity as a separate disease. Bluetongue (BT) was described for the first time by Duncan Hutcheon in 1880, although it was probably always endemic in wild ruminants and only became a problem when highly susceptible Merino sheep were introduced to the Cape in the late 18th century. The filterability of the AHS virus (AHSV) was demonstrated in 1900 by M’Fadyean in London, and that of the BT virus (BTV) in 1905 by Theiler at Onderstepoort, thus proving the viral nature of both agents. Theiler developed the first vaccines for both diseases at Onderstepoort. Both vaccines consisted of infective blood followed by hyper-immune serum, and were used for many years. Subsequent breakthroughs include the adaptation to propagation and attenuation in embryonated eggs in the case of BTV and in mouse brains for AHSV. This was followed by the discovery of multiple serotypes of both viruses, the transmission of both by Culicoides midges and their eventual replication in cell cultures. Molecular studies led to the discovery of the segmented double-stranded RNA genomes, thus proving their genetic relationship and leading to their classification in a genus called Orbivirus. Further work included the molecular cloning of the genes of all the serotypes of both viruses and clarification of their relationship to the viral proteins, which led to much improved diagnostic techniques and eventually to the development of a recombinant vaccine, which unfortunately has so far been unsuitable for mass production.Paper given at the 30th World Veterinary Congress, October 2011, Cape Town, South Africa.http://www.jsava.co.z

The Theiler Memorial Trust Award

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Biotechnology, viral oncogenesis and jaagsiekte

A brief description is given of the discovery of retroviral and cellular oncogenes and of their putative role in oncogenesis. Attempts to apply the biotechnological techniques that were so successful in the study of other retroviruses to the newly-discovered jaagsiekte retrovirus are briefly reviewed.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

A scanning and transmission electron-microscopy study of jaagsiekte lesions

A scanning electron microscopy (SEM) and transmission electron microscopy (TEM) study was made of lesions from acute, experimentally induced cases of jaagsiekte. In the SEM study tumour cells were easily identified by the abundant microvilli on their peripheral surface. The SEM study gave further insight into the development of lesions and the spatial relationship of cells involved in jaagsiekte. TEM revealed that the tumour cells were in a state of rapid protein synthesis and had many characteristics in common with other malignant cells.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on the in vitro and the in vivo transcription of the bluetongue virus genome

Bluetongue virus particles, converted to a high density form by the selective removal of two polypeptides from their protein capsids, possess RNA dependent RNA polymerase activity. The enzyme, which can be assayed by its ability to incorporate nucleoside triphosphates into RNA in an in vitro system, is dependent on magnesium ions, is stimulated by the presence of manganese ions and shows maximal activity at 28°C. The product of the in vitro reaction was isolated and shown to consist of ten single-stranded RNA segments which can be hybridized with double-stranded RNA isolated from purified bluetongue virus (BTV). The hybridization product, when analyzed by means of polyacrylamide gel electrophoresis, is indistinguishable from a hybrid obtained using BTV messenger RNA isolated from infected cells. It is therefore deduced that the BTV genome is fully transcribed both in vitro and in vivo by an enzyme present in the viral capsid.The articles have been scanned in colour with a HP Scanjet 5590;300dpi. adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Immunosuppression in new-born lambs

A novel technique, based on cytotoxicity-neutralization, was developed for the in vitro titration of anti-sheep lymphocyte and anti-sheep macrophage sera. The titres obtained for a number of antisera were compared with those found in an agglutination assay. Anti-lymphocyte sera with a high cytotoxicity-neutralization titre very effectively suppressed the number of circulating lymphocytes the peripheral blood of treated new-born lambs, thus indicating in vivo immunosuppressive activity.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

On the relationship between bluetongue, African horsesickness and reoviruses : hybridization studies

The double-stranded ribonucleic acid from bluetongue virus (BTV), African horsesickness virus (AHSV) and reovirus has been tested for hybridization with messenger RNA derived from BTV and reovirus-infected cells. No relationship was found between reovirus and BTV or AHSV, but a small amount of hybridization between BTV and AHSV did occur.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Demonstration of growth-inhibitory as well as growth-stimulatory factors in medium conditioned by lung lavage cells stimulated with a chemotactic factor secreted by jaagsiekte tumour cells

Both growth-inhibitory and growth-stimulatory factors were detected in vitro in medium from chemotactically stimulated cultures of lung lavage cells. The macrophage component of the lavage cells was found to produce a growth stimulatory factor that was replaced by a growth inhibitory factor following chemotactic factor stimulation.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201