Yeast in an Egg Shell

Mar 28, 2008

Nature’s eggshells have inspired Chinese researchers: A team led by Ruikang Tang at Zhejiang University have successfully equipped living yeast cells with an artificial mineral coating. As reported in the journal Angewandte Chemie, the hard inorganic shells protect the cells, allowing them to survive longer storage times. By incorporating iron oxide particles into the shells the researchers were also able to make them magnetic.

Our breakfast egg is an anomaly of nature; a single cell protected by a thin mineral layer. With the exception of some tiny amoebas and diatoms, individual cells do not normally have a hard shell. The Chinese researchers have now developed a strategy to equip cells of baker’s yeast, Saccharomyces cerevisiae, with an artificial shell of calcium phosphate.

First, a synthetic polymer, such as a polyacrylate, is attached to the cell walls of the yeast cells. The negatively charged carboxylate groups (COO) of the polymer stick out into the surrounding calcium phosphate containing solution.

Positively charged calcium ions from the medium bind to the carboxylate groups and attract the negatively charged phosphate ions to form nuclei for the growth of calcium phosphates. In the course of the mineralization process, the yeast cells are completely encapsulated by an inorganic layer.

Yet the cells remain viable. They enter into a resting state, in which they even survive a lack of the nutrients normally used for yeast storage. With their shells, the yeast cells last much longer; whereas a maximum of 20 % of yeast cells are normally viable after a month, 85 % of the cells with shells last that long. In addition, the shell protects the cells from unfavorable external conditions, even the attack of enzymes that break up cell walls. When the shell is dismantled by lightly acidic conditions or ultrasound, the yeast cells resume their normal cell cycle.

Genetically modified yeasts are also used to produce important pharmaceutical agents, such as interferon and insulin, as well as vaccines. In molecular biology research, easily cultivated yeasts are often used for basic investigations of cellular processes and for the diagnosis of human diseases.

The protection and improved shelf life provided by the shell could increase their potential in this field. In addition, the shell can act as a scaffold for chemical and biological property modifications. The team was thus able to produce magnetic yeast cells by the inclusion of iron oxide nanoparticles in the shell.

Citation: Ruikang Tang, Zhejiang University, Yeast Cells with an Artificial Mineral Shell: Protection and Modification of Living Cells by Biomimetic Mineralization, Angewandte Chemie International Edition, doi: 10.1002/anie.200704718

Source: Angewandte Chemie

Explore further: Researchers develop models to study polyelectrolytes, including DNA and RNA

add to favorites email to friend print save as pdf

Related Stories

Engineering cells for more efficient biofuel production

Feb 18, 2013

In the search for renewable alternatives to gasoline, heavy alcohols such as isobutanol are promising candidates. Not only do they contain more energy than ethanol, but they are also more compatible with existing gasoline-based ...

Bacteria make thrift a habit, researchers find

Aug 25, 2010

(PhysOrg.com) -- In these lean times, smart consumers refuse to pay a lot for throwaway items, but will shell out a little more for products that can be used again and again. The same is true of bacteria and ...

Researchers report oral delivery system for RNAi therapeutics

Apr 29, 2009

Researchers at the University of Massachusetts Medical School (UMMS) report today on a novel approach to the delivery of small bits of genetic material in order to silence genes using "RNA interference"—and in the process, ...

Novel pandemic flu vaccine effective against H5N1 in mice

Mar 01, 2009

Vaccines against H5N1 influenza will be critical in countering a possible future pandemic. Yet public health experts agree that the current method of growing seasonal influenza vaccines in chicken eggs is slow and inefficient.

Recommended for you

Water and sunlight the formula for sustainable fuel

1 hour ago

An Australian National University (ANU) team has successfully replicated one of the crucial steps in photosynthesis, opening the way for biological systems powered by sunlight which could manufacture hydrogen ...

Rice chemist wins 'Nobel Prize of Cyprus'

1 hour ago

Rice University organic chemist K.C. Nicolaou has earned three prestigious international honors, including the Nemitsas Prize, the highest honor a Cypriot scientist can receive and one of the most prestigious ...

Researchers create engineered energy absorbing material

2 hours ago

(Phys.org) —Materials like solid gels and porous foams are used for padding and cushioning, but each has its own advantages and limitations. Gels are effective as padding but are relatively heavy; gel performance ...

Solar fuels as generated by nature

2 hours ago

(Phys.org) —Society's energy supply problems could be solved in the future using a model adopted from nature. During photosynthesis, plants, algae and some species of bacteria produce sugars and other energy-rich ...

New tool identifies therapeutic proteins in a 'snap'

3 hours ago

(Phys.org) —In human and bacterial cells, glycosylation – the chemical process of attaching complex sugar molecules to proteins – is as fundamental as it gets, affecting every biological mechanism from cell signaling ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

NeilFarbstein
1 / 5 (1) Mar 29, 2008
So what