Production of positive controls for calcivirus-specific PCR using recombinant baculiovirus technology

Recent advances in our knowledge of the genetic structure of human caliciviruses (HuCVs) and small round-structured viruses (SRSVs) have led to the development of polymerase chain reaction (PCR)-based molecular tests specific for these viruses. These methods have been developed to detect a number of human pathogenic viruses in environmental samples including water, sewage and shellfish. HuCVs and SRSVs are not culturable, and no animal model is currently available. Therefore there is no convenient method of preparing viruses for study or for reagent production. One problem facing those attempting to use PCR-based methods for the detection of HuCVs and SRSVs is the lack of a suitable positive control substrate. This is particularly important when screening complex samples in which the levels of inhibitors present may significantly interfere with amplificiation. Regions within the RNA polymerase regions of two genetically distinct human caliciviruses have been amplified and used to produce recombinant baculoviruses which express RNA corresponding to the calicivirus polymerase. This RNA is being investigated as a positive control substrate for PCR testing, using current diagnostic primer sets. Recombinant baculovirus technology will enable efficient and cost-effective production of large quantities of positive control RNA with a specific known genotype. We consider the development of these systems as essential for successful screening and monitoring applications.

Combating fish disease. An explanation of the controls on notifiable fish diseases in Great Britain and advice on steps to prevent the spread of disease

For many years action has been taken to prevent the introduction and spread of serious fish diseases in Great Britain. In 1993 national rules were replaced by European Union wide rules designed to promote trade within the single market while safeguarding those parts of the Union with a high fish health status - such as this country. This booklet details the checks and controls which are applied to prevent the spread of disease outbreaks in this country. One can see that different rules apply to different diseases, generally reflecting the severity and other characteristics of the disease. The booklet also tries to explain the diseases and helps to recognise symptoms. This booklet is split into three parts: Part 1 gives an overview of the controls; Part 2 gives details for each of the diseases; and Part 3 gives advice on some of the precautions you can take to guard against the spread of disease.

Climatic controls on diatom succession at Elk Lake, Minnesota [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Sediment traps placed in the profundal region of Elk Lake, north central Minnesota during the 1979 spring and 1983-84 fall and spring seasons monitored seasonal diatom production for two climatically distinctive periods.