The Tea Lover's Organelle: Tannosome

A team of French and Hungarian scientists identified an organelle responsible for producing the chemical that gives tea, wine, and unripe fruit a bitter flavor according to Scientific American's blogger Jennifer Frazer.

The tannosome produces tannins, the bitter chemicals that enhances flavor but deter many herbivores. Tannin denatures proteins in the herbivore, making it difficult for the animal to process its food and produce energy at a regular rate. For more information on tannins specifically, see this explanation of the biotoxins from Cornell.

Previously, scientists assumed that the rough endoplasmic reticulum produced the tannins, which were then stored in the vacuoles. Instead, the team found that they are produced within the chloroplasts, and stored in special vesicles  called tonoplasts that prevent the chemicals from disintegrating their own cell's proteins.

Photo credit: Jean-Marc Brillouet, et al. (from the original research paper in the Annals of Botany).
The new process, proposed by the researchers, suggests that tannosomes are found within the inner membrane of the vascular plants' chloroplasts. The tannosomes make the tannins, which are then shuttled by a vesicle into the vacuole where they are stored inside a tonoplast, which separates them from the other contents of the vacuole.

Since organelles are useful in separating biological processes, it is not entirely surprising that tannins require their own production centers. It is worth noting that even the collection of organelles may still increase as scientists turn their attention to new processes and chemicals.

Custom DNA: scientists flouresce DNA to visualize cell

(Photo credit: Wyss Institute) This fluorescently tagged image shows the light emitted within organelles in a human cell.

Harvard researchers at the Wyss Institute for Biologically Inspired Engineering recently created this image of a human cell enhanced by Exchange-PAINT, a method that marks certain organelles with fluorescent markers, according to the Wyss Institute's Feb. 3 press release. 

The green displays microtubules, the red the Golgi Apparatus, the yellow the peroxisomes, and the purple, the mitochondria.

One of the team leaders, Peng Yin, Ph.D, published his dissertation (will prompt to open a document) in 2012 on watching metabolic reactions take place through fluorescent tagging. At the time, however, the samples were still dead, and he was merely comparing relative levels over time.
  
This new method allows scientists not only to see objects that are extremely close together in higher resolution than ever, but also specimens that are still living. 

The goal of such imaging is to analyze processes as they occur in real time, watching each of the components interact.These images display many of those components, organelles, simultaneously, and suggest that the right combinations of markers could allow scientists to observe processes in the organelles, upholding or rejecting earlier hypotheses.
 

German researchers identify protein and organelle that cause Microcephaly

A team of researchers led by Erich Nigg at the Biozentrum of the University of Basel in Germany identified a cell signal critical to cell division, according to an article on MedicalXpress posted on Jan. 31, 2014.

One of the centromeres, the organelles that help chromosomes migrate to the appropriate regions during mitosis, duplicates before cell division occurs with the help of a protein known as STIL.

Nigg's team identified KEN-Box, a cell signal that triggers the degradation of STIL after the centromere has been duplicated.

If KEN-Box does not signal degradation at the right time, the centomeres may continue to divide.  If this occurs, a multi-polar mitotic division occurs and chromosomes are not distributed properly.

This depicts a multi-polar division in which the there are four centrioles (red) attempting to divide the chromosomes (blue). (Photo credit: MedicalXpress)

When this occurs in brain cells (neurons), Microcephaly may occur, a syndrome usually marked by an abnormally small head and often mental and developmental problems and delays, as explained by the National Institute of Neurological Disorders and Stroke.

This may be linked to drug and alcohol abuse during pregnancy, although the mechanism for such interaction has yet to be proposed.