In situ hybridization technique using an immunogold silver staining system

In situ hybridizations of Eperythrozoon suis visualized by electron microscopy

Eperythrozoon suis is an extracellular red blood cell parasite that causes icteroanemia and poor growth performance in feeder pigs and has been associated with anemias in baby pigs and reproductive failures in sows. At present, few efficient tests are available for the diagnosis and study of E. suis infection in swine. This report discusses how a recently developed recombinant DNA probe (KSU-2) specific to E. suis DNA was utilized in in situ DNA hybridizations that couple biotinylated TaqI digested products of KSU-2 DNA with an immunogold detection system allowing the visualization by transmission electron microscopy of the gold particles within eperythrozoon organisms. Specific labelling by the probe of eperythrozoon organisms demonstrated a pattern that changed with the various stages of the eperythrozoon life cycle.

In situ hybridisation in perspective

In the introduction to this review two questions were posed: is the technology associated with ISH ready for general use, and will the method become an important investigative tool? With the exception of the demonstration of some single and low copy sequences, non-radioactive ISH is now sufficiently developed and simplified to make it a routine technique. It is also clear that ISH will continue to have an important research role. In diagnostic pathology the technique is already providing valuable information and the present decade should see the development of many more diagnostic applications.

Localization in situ of specific mRNA using thymine-thymine dimerized DNA probes. Sensitive and reliable non-radioactive in situ hybridization

In situ hybridization has been recognized as a powerful technique for localizing specific nucleic acids such as mRNA and viral DNA in individual cells. For in situ hybridization, the use of a non-radioactive probe is considered superior to that of a radioactive one from viewpoints of resolution, probe stability and personal safety. Although various non-radioactive labels are currently available, some interfere with the formation of hybrids and some increase steric hindrance and prevent penetration of the labeled nucleic acid probe into cells and tissues. Recently, we have developed a method using thymine-thymine (T-T) dimerized DNA as a non-radioactive probe. This is simple to make, since it dose not require separation of labeled DNA from unreacted labeling compounds, and T-T dimer will not alter the chemical and physical nature of the probe. In this paper, we describe the tissue processing procedures that are suited for the T-T dimerized DNA probes, and the recent new findings on methodological aspects, particularly the use of synthetic oligodeoxynucleotide probes.

Application of 1 nm gold probes on paraffin wax sections for in situ hybridisation histochemistry

An in situ hybridisation technique that uses 1 nm immunogold reagents and silver enhancement was devised to detect biotinylated DNA viral probes in formalin fixed, paraffin wax sections of human cervix. DNA probes labelled with biotin-11-deoxyuridine triphosphate were detected after hybridisation to nucleic acid sequences by an antibiotin antibody, followed by a gold labelled secondary antibody. Silver enhancement then permitted visualisation of the signal at the light microscopic level. The method was reliable and produced less background staining than previously described methods. The signal could be enhanced by epi polarisation microscopy. Furthermore, biotinylated DNA probes may be detected directly by a 1 nm gold labelled goat antibiotin antibody without loss of labelling intensity, and this may be preferable to the longer two layer technique, previously described.