in vivo

Examples of in vivo in the following topics:

• In Vivo Testing

  • In vivo testing using animal models of disease help discover new ways of solving complex health problems.
  • In vivo methods refer to the use of animals as a conduit to generate purified polyclonal antibody solutions (antiserum) for research purposes.
  • In vivo testing follows strict guidelines and humane animal use ethics.
  • In vivo testing remains a crucial step for the evaluation of in vitro experimental findings and the production of immunological solutions needed for the diagnosis of human diseases.
  • Animals are used in laboratory experiments to translate in vitro findings.

• General Staining Methods

  • Staining is a technique used in microscopy to enhance contrast in a microscopic image.
  • In-vivo staining is the process of dyeing living tissue -- in vivo means "in life" (as contrasted to in-vitro staining).
  • There are an incredible number of stains that can be used in a variety of different methods.
  • In some cases, cells may be grown directly on a slide.
  • Live, in-vivo staining microscopy shares many of these steps, with the exception of fixation, which invariably kills the microbe to be examined.

• Mapping Protein-Protein Interactions

  • In living organisms most of the biological functions are mediated by complex multi-component protein machineries and network activities.
  • Several methodologies exist to study the interaction of proteins in vivo.
  • The complete map of protein interactions that can occur in a living organism is called the interactome.
  • The yeast two-hybrid screening system is an effective and quick tool for the in vivo study of protein–protein interaction both in prokaryotes and eukaryotes.
  • In the absence of an interaction the domains remain distant, preventing a detectable output.

• Ribosomes

  • Proteins synthesized in each of these locations serve a different role in the cell.
  • In prokaryotes, ribosomes can be found in the cytosol as well.
  • In most bacteria, the most numerous intracellular structure is the ribosome which is the site of protein synthesis in all living organisms.
  • In vivo assembly of the 30S subunit has two intermediates (p130S and p230S) and the 50S subunit has three intermediates (p150S, p250S, and p350S).
  • The intermediates in the in vivo assembly are precursor rRNA which is different from in vitro which uses matured rRNA.

• Two-Hybrid Analysis

  • Several methodologies exist to study the interaction of proteins in vivo.
  • The yeast two-hybrid screening system is an effective and quick tool for the in vivo study of protein–protein interaction both in prokaryotes and eukaryotes.
  • In the absence of an interaction the domains remain distant, preventing a detectable output.
  • In the split-ubiquitin system, two integral membrane proteins to be studied are fused to two different ubiquitin moieties: a C-terminal ubiquitin moiety ("Cub", residues 35–76) and an N-terminal ubiquitin moiety ("Nub", residues 1–34).
  • In addition to being fused to an integral membrane protein, the Cub moiety is also fused to a transcription factor (TF) that can be cleaved off by ubiquitin specific proteases.

• Dendritic Cells

  • Dendritic cells are present in lymphoid organs, the epithelia of the skin, the gastrointestinal and respiratory tracts, and in most parenchymal organs.
  • Most, called myeloid dendritic cells, are related in lineage to mononuclear phagocytes.
  • Mature dendritic cells reside in the T cell zones of the lymph nodes, and in this location they display antigens to T cells.
  • Dendritic cells are constantly in communication with other cells in the body.
  • For example, stimulating dendritic cells in vivo with microbial extracts causes the dendritic cells to rapidly begin producing interleukin 12 (IL-12).

• Whole-Genome DNA-Binding Analysis

  • This has created a need for more efficient techniques to determine which parts of these sequences are bound in-vivo by the proteins controlling processes; such as gene expression, DNA replication and chromosomal mechanics.
  • The first step in the ChIP-Chip procedure is to fix protein-DNA interactions in living cells by chemical crosslinking.
  • In practice, formaldehyde is used in most ChIP-Chip experiments.
  • The two differentially-labeled DNAs are hybridized to the same microarray and the difference in fluorescence intensity gives a measure of the enrichment .

• Electron Microscopy

  • An electron beam has an exceptionally short wavelength and can hit most objects in its path, increasing the resolution of the final image captured.
  • The electron beam is designed to travel in a vacuum to limit interference by air molecules.
  • TEM can project images in a much higher resolution—up to the atomic level of thinner objects.
  • It allows the visualization of microorganisms in three dimensions as the electrons are reflected when passed over the specimen.
  • observe individual viruses and macromolecular complexes in their natural biological context.

• Anaerobiosis and N2 Fixation

  • In essence, O2 binds to the iron (Fe) found in nitrogenases and blocks their ability to bind to N2.
  • To protect nitrogenases, there are mechanisms for nitrogen fixers to protect nitrogenase from oxygen in vivo.
  • Many rhizobia, nitrogen fixing bacteria, live in a symbiotic relationship with plants known as legumes.
  • In plants infected with Rhizobium, (legumes such as alfalfa or soybeans), the presence of oxygen in the root nodules would reduce the activity of the oxygen-sensitive nitrogenase.
  • It has close chemical and structural similarities to hemoglobin, and, like hemoglobin, is red in colour.

• Anoxygenic Photosynthesis

  • Phototrophy is the process by which organisms trap light energy (photons) and store it as chemical energy in the form of ATP and/or reducing power in NADPH.
  • Anoxygenic phototrophs have photosynthetic pigments called bacteriochlorophylls (similar to chlorophyll found in eukaryotes).
  • Bacteriochlorophyll a and b have wavelengths of maximum absorption at 775 nm and 790 nm, respectively in ether.
  • In vivo however, due to shared extended resonance structures, these pigments were found to maximally absorb wavelengths out further into the near-infrared.
  • The cyclic nature of the electron flow is typified in purple non-sulfur bacteria.