Tunneling Nanotubes :Tunneling Nanotubes Life’s Secret Network Prepared by Ayesha Rehman Source: Internet


: Tunnelling nanotubes were discovered by Rustom in 2000. These are the nanometer scale tubes forming between relatively distant cells and transferring proteins and even organelles between cells. They connect the animal cells interiorly. Before its discovery , gap junctions were considered to be the closest connections between the cells interior in animals, a channel through middle of each gap junction would connect the cells interiors. However it had a drawback , it will only allow the ions and small molecules such as amino acids to pass through. But nanotubes are 50-200nm thick hence will allow large molecules such as proteins and organelles to pass through. TNT Prepared by Ayesha Rehman


Everywhere… :Everywhere… Prepared by Ayesha Rehman


Transfer of Organelles :Transfer of Organelles TNT allows the transfer of organelles between the cells , it was discovered in mice that progenitor cells injected after heart attacks seem to turn into new heart muscle cells, replacing dead tissue cells . Argument that is given for this is that they form connections through TNT and would allow organelles to pass through them plus the transfer by the use of nanotubes of signaling molecules and proteins called transcription factors helps to convert the progenitor cells. Prepared by Ayesha Rehman


Structure :Structure It is believed that TNT come into many shapes and sizes of various thickness and lengths. These nanotubes is made of what is not known yet however it was discovered that it contained a motor protein, myosin Va. And these proteins are thought to help the movement of substances through TNT. Moreover they are extremely weak i.e. they are highly sensitive, which is why they were discovered so late. Source: NewScientist Prepared by Ayesha Rehman


An extract from the main Article. :An extract from the main Article. It pays to network The discovery of tunnelling nanotubes has led to speculation about just how far their influence extends. Some think they might play a crucial role in development. One of the key outstanding questions in biology has to do with how cells communicate with each other as an embryo develops. We know that some cells release molecules called morphogens, which diffuse through the intercellular medium. The resulting concentration gradient tells cells where they are in the embryo and they can then develop accordingly. But this does not explain everything.For instance, two very distant cells can show similar patterns of gene expression while other cells nearby do not. If a morphogen gradient is responsible, then surely the cells closer to the one releasing the morphogen should also be responding.Such observations could be explained if morphogens are distributed directly to certain cells through a network of nanotubes, speculates Hans-Hermann Gerdes of the University of Bergen in Norway. "It would be much more appealing for nature to have this direct line," he says. Plants cells are known to use their version of nanotubes, called plasmodesmata, to transfer microRNAs that influence gene activity from one cell to another during embryogenesis. "These microRNAs lead to certain expression patterns in adjacent and also very remote cells," says Gerdes. Mammalian cells could also be doing the same.Even more speculative is the idea that the development of organs could be influenced by tunnelling nanotubes. It is not well understood how organs "know" how big they should get, or the exact shape to take. "These are all open questions," says Gerdes. He speculates that if the cells in a given organ were connected by nanotubes, then these connections could help establish a feedback mechanism that provides the necessary information for the organ to grow to the right size and shape. Prepared by Ayesha Rehman


Resistant of Cancer cells against Chemotherapy :Resistant of Cancer cells against Chemotherapy Prepared by Ayesha Rehman They are simply spectacular resulting into communications between the cells.