Giant cell reveals metabolic secrets

Jan 27, 2012
Figure 1: The freshwater alga Chara australis, which has giant cells ideal for cell biology studies. Credit: 2012 Akira Oikawa

Chemical reactions within the cell produce intermediate and end products in the form of small molecules called metabolites. Using an approach called metabolomics, a Japanese research team led by Kazuki Saito of the RIKEN Plant Science Center, Yokohama and Tsuruoka, has elucidated the localization and dynamics of 125 metabolites within a single giant cell of the freshwater alga Chara australis. The team’s findings provide important insights into the fundamental processes of cells in general.

Metabolites play important roles in the regulation of critical biological processes, such as growth, differentiation, and, in the case of so-called ‘secondary metabolites’, chemical defense. “Metabolomics is the systematic study of these unique chemical footprints, and involves identifying and characterizing the many metabolites found in a cell, tissue, organ or organism, as well as their production, distribution and dynamics,” explains Saito.

Because the enzymes involved in producing and converting different metabolites are often localized within subcellular structures called organelles, biologists generally assumed that metabolites are also highly compartmentalized within the cell, but none had demonstrated this comprehensively.  

“Understanding the compartmentalization and dynamics of metabolites within single organelles represents an enormous technical challenge, not least because of the tiny size of these structures in most cells,” says Saito.

He and his colleagues therefore turned to C. australis as a model system (Fig. 1). This species has a particular cell type, called an internodal cell, which can grow to a length of around 20 centimeters. Because of their large size and volume, internodal cells are widely used to study various aspects of cell biology, including membrane physiology. The researchers purified single vacuoles, a type of organelle, from these . They then used a battery of sophisticated metabolomic techniques to determine the and dynamics of metabolites in the vacuole and other cellular fractions collectively known as the cytoplasm.

Focusing on phosphate compounds, Saito and colleagues detected 125 known metabolites, and showed that they fluctuated independently in the vacuole and cytoplasm under various light conditions. They therefore concluded that metabolites are spatially regulated within the cell, moving between the vacuole and the cytoplasm according to conditions. “Ours is the first study to confirm specific compartmentalization of comprehensive metabolites in a single vacuole from a single cell,” notes Saito.

Using a specialized microinjection technique, they researchers also observed metabolite transport across the membrane surrounding the vacuole. This suggested to them that the vacuolar membrane plays an important role in regulating transport of in and out of the vacuole.

Explore further: Fighting bacteria—with viruses

More information: Oikawa, A., et al. Metabolomics of a single vacuole reveals metabolic dynamism in an alga Chara australis. Plant Physiology 157, 544-555 (2011).

add to favorites email to friend print save as pdf

Related Stories

Know your tomatoes

May 13, 2011

Genetically modified (GM) tomatoes look much the same as traditional varieties (Fig. 1). But are they? By comparing the chemical diversity of strains of GM tomatoes with a control strain and traditional reference ...

Computer predicts anti-cancer molecules

Jun 17, 2008

A new computer-based method of analyzing cellular activity has correctly predicted the anti-tumour activity of several molecules. Research published today in BioMed Central's open access journal Molecular Cancer describes 'CoMet ...

Getting around gene loss

Oct 29, 2010

Genes ‘knocked out’ experimentally in metabolic networks of the model plant species, Arabidopsis thaliana (Fig. 1), are compensated for by duplicate genes or alternative synthetic pathways, accord ...

Urinary metabolomic profile and gastric cancer

Mar 08, 2011

A research team from China investigated urinary metabolites expression changes among three mice groups using gas chromatography/mass spectrometry. Ten metabolites have differences between the normal group and the cancer group ...

Recommended for you

Fighting bacteria—with viruses

Jul 24, 2014

Research published today in PLOS Pathogens reveals how viruses called bacteriophages destroy the bacterium Clostridium difficile (C. diff), which is becoming a serious problem in hospitals and healthcare institutes, due to its re ...

Atomic structure of key muscle component revealed

Jul 24, 2014

Actin is the most abundant protein in the body, and when you look more closely at its fundamental role in life, it's easy to see why. It is the basis of most movement in the body, and all cells and components ...

Brand new technology detects probiotic organisms in food

Jul 23, 2014

In the food industr, ity is very important to ensure the quality and safety of products consumed by the population to improve their properties and reduce foodborne illness. Therefore, a team of Mexican researchers ...

Protein evolution follows a modular principle

Jul 23, 2014

Proteins impart shape and stability to cells, drive metabolic processes and transmit signals. To perform these manifold tasks, they fold into complex three-dimensional shapes. Scientists at the Max Planck ...

Report on viruses looks beyond disease

Jul 22, 2014

In contrast to their negative reputation as disease causing agents, some viruses can perform crucial biological and evolutionary functions that help to shape the world we live in today, according to a new report by the American ...

User comments : 0