Cells show diverse appearances and sizes, ranging from some 30 nanometers up to several meters in length. Besides the classical prokaryotic and eukaryotic cells, there are also very bizarre cells such as the highly reduced symbiotic mitosomes which lack DNA. Other examples of extremely small...

The volvocaceans are a closely related group of green flagellates that range in size and complexity from colonial forms that contain a small number of identical cells, to Volvox in which there is a division of labor between several thousand terminally differentiated somatic cells and a small...

Cell-to-cell communication in plants occurs via plasmodesmata (Pd), dynamic membrane-lined pores in the plant cell wall that provide symplasmic continuity between adjacent cells. Communication through Pd involves the trafficking of protein and RNA macromolecules, and also includes the trafficking...

Gap junctions provide one of the most common forms of intercellular communication. The structures underlying these communicating cell junctions1 were soon resolved in membrane associated particles forming aggregates of six subunits.2 They are composed of membrane proteins that form a channel that...

The sapwood of trees contains living cells in the form of ray and axial parenchyma. Communication between these cells is important in controlling the differentiation of xylem cells, movement of nutrients and water, defence against pathogens and damage repair. These parenchyma cells are therefore...

In the last few years, the intercellular trafficking of regulatory proteins has emerged as a novel mechanism of cell-to-cell communication in plant development. Here I present a review of the documented cases of transcription factors movement in plants and examine the common themes underlying...

The endothelium is an efficient barrier located at the boundary between vascular and perivascular compartments. However, it is also regarded to as a permeable filter that contains aqueous pores and allows selective passage of solutes between these compartments. Two distinct routes of...

Life History: Sexual and Asexual ReproductionThose who study ciliates have struggled over the years to establish a place in the pantheon of model organisms.1 Eukaryotic cell biologists have turned profitably to yeast models for the powerful genetic tools at their disposal, while developmental...

Conjugative plasmid transfer is the most important mechanism for bacteria to deliver and acquire genetic information to cope with rapidly changing environmental conditions. To transfer genetic information intercellularly mating cell-cell channels between donor and recipient bacteria have to...

Homeoproteins are a class of transcription factors that have the unusual property of intercellular transfer, both in metaphytes and in metazoans. Here we discuss the cellular mechanisms and the function of this transfer.

Despite the diversity of intercellular connections that are the subject of this book, most eukaryotic cells retain their distinct character as mononucleated compartments. Their membranes describe morphologically separate cytoplasms, while electrical connectivity and low-flux intercellular...

Cell-to-cell spread of retroviruses via virological synapse (VS) contributes to overall progression of disease. VS are specialized pathogen-induced cellular structures that facilitate cell-to-cell transfer of HIV-1 and HTLV-1. VS provide a mechanistic explanation for cell-associated retroviral...

Transient intercellular bridges are seen between a wide variety of cells before the completion of cytokinesis.1 However, these are distinct from stable intercellular bridges that remain persistent after incomplete cytokinesis.2 The diameter of the cytoplasmic bridges is rather big, 1-10 mm,...

Plasmodesmata (PD) are cell-cell channels interconnecting all the cells of the plant body into a huge syncytium, which makes plants ‘supracellular’ organisms. Recent studies have clearly revealed that both the targeting and gating of PD is highly regulated. Importantly, it is known that...

In most animal species, female and male gametes are produced within clusters of germ cells which share a common cytoplasm through cell-cell channels. In Drosophila ovaries, these cells synchronise their divisions and specialise one cell of the cluster as the future egg. Both processes are...

Intercellular communication is inherent to life, and has evolved with extremely diversified forms from prokaryotes to the most sophisticated multicellular eukaryotes. Haematopoietic cells from mammalians have adapted a transient and highly versatile means for the direct transfer of...

Plant viruses move from cell to cell through plasmodesmata, which are complex gatable pores in the cell wall. As plasmodesmata normally allow the diffusion of only small molecules, virus movement is only achieved by the action of virus-encoded movement proteins that biochemically or...

Intercellular communication is a major requirement for the development and maintainance of multicellular organisms. Diverse mechanisms for the exchange of signals between cells during evolution have been established. These mechanisms include intercellular membrane channels between plant...

The evolution of multicellular organisms entailed the formation of biological compartments separated by epithelial cellular barriers. As a consequence, strategies have evolved to move exchange materials between these compartments for nutrition, wastes removal and information exchange, while still...

Plasmodesmata (PD) permit diffusion of small metabolites and proteins, as well as active trafficking of specific RNAs and proteins. Their structure and distribution vary according to species, cell type, physiological function and stage of development.Two mechanisms for PD trafficking have...

Human blood cell similar to embryonic and nerve cells can extend thin and very long exten-\r\n sions having the same diameter along the entire length called cytonemes. Cytonemes were \r\n shown to connect blood cells over a distance of several cell diameters and transport membrane proteins,...

Sieve tubes seem to dispose of diverse mechanisms which are able to seal or plug sieve pores - very specialized and evolutionarily transformed cell-cell channels - in response to injury. Two major devices for their closure are distinguished: a putative rapid (several seconds) plugging by...

The formation of channels between fungal hyphae by self fusion is a defining feature of filamentous fungi, and results in the fungal colony being a complex interconnected network of hyphae. During the vegetative phase hyphal fusions are commonly formed during colony establishment by...