Bacteria connect to each other and exchange nutrients

It is well-known that bacteria can support each others’ growth and exchange nutrients. Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, and their colleagues at the universities of Jena, Kaiserslautern, and Heidelberg, however, have now discovered a new way of how bacteria can achieve this nutritional exchange. They found that some bacteria can form nanotubular structures between single cells that enable a direct exchange of nutrients.    

Bacteria usually live in species-rich communities and frequently exchange nutrients and other metabolites. Until now, it was unclear whether microorganisms exchange metabolites exclusively by releasing them into the surrounding environment or whether they also use direct connections between cells for this purpose. Scientists from the Research Group Experimental Ecology and Evolution at the Max Planck Institute for Chemical Ecology in Jena, Germany addressed this question using the soil bacterium Acinetobacter baylyi and the gut microbe Escherichia coli. By experimentally deleting bacterial genes from the genome of both species, the scientists generated mutants that were no longer able to produce certain amino acids, yet produced increased amounts of others.

In co-culture, both bacterial strains were able to cross-feed each other, thereby compensating the experimentally induced deficiencies. However, separating the two bacterial strains with a filter that allowed free passage of amino acids, yet prevented a direct contact between cells, abolished growth of both strains. “This experiment showed that a direct contact between cells was required for the nutrient exchange to occur,” explains Samay Pande, who recently obtained his PhD at the Max Planck Institute in Jena on this research project and now started a postdoc at the ETH Zürich.

Electron micrograph of genetically modified Acinetobacter baylyi and Escherichia coli strains. The bacteria exchange amino acids via nanotubes (i.e. tube-like connections between cells). Credit: Universitätsklinikum Jena/Martin Westermann

While not original art, it’s still a fun piece. BBL’s CHROMagar Orientation agar is the canvas for this piece of agar art. Chromogens in the agar release a colored compound when hydrolyzed by specific enzymes allowing certain bacteria to appear different colors on it. The brown color is Proteus mirabilis, a bacterium known for its swarming motility that is a common cause of urinary tract infections. The white color is Acinetobacter baumanii, an opportunistic bacterium that can cause infection in people with weakened immune systems. It is often resistant to multiple antibiotics and can be spread around hospital environments. The blue-green color is Enterococcus faecalis, a bacterium that colonizes the GI tract and is a common cause of lower urinary tract infections as well as more invasive infections in immunocompromised hosts. It is a hardy organism that can acquire resistance to multiple antibiotics and spread around the hospital environment. The dark blue color is Klebsiella pneumonia, a bacterium found in the normal flora of the mouth, skin and intestines. It can cause different types of healthcare-associated infections including pneumonia, bloodstream infections, wound or surgical site infections and meningitis.

Source:  Melanie Sullivan
First Nations’ ancient medicinal clay shows promise against today’s worst bacterial infections
Naturally occurring clay from Kisameet Bay, B.C. — long used by the Heiltsuk First Nation for its healing potential — exhibits potent antibacterial activity against multidrug-resistant pathogens. E…

Naturally occurring clay from Kisameet Bay, B.C. — long used by the Heiltsuk First Nation for its healing potential — exhibits potent antibacterial activity against multidrug-resistant pathogens, according to new research from the University of British Columbia.

The researchers recommend the rare mineral clay be studied as a clinical treatment for serious infections caused by ESKAPE strains of bacteria.

The so-called ESKAPE pathogens — Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae,Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species — cause the majority of U.S. hospital infections and effectively ‘escape’ the effects of antibacterial drugs.

“Infections caused by ESKAPE bacteria are essentially untreatable and contribute to increasing mortality in hospitals,” said UBC microbiologist Julian Davies, co-author of the paper published today in the American Society for Microbiology’s mBio journal.

“After 50 years of over-using and misusing antibiotics, ancient medicinals and other natural mineral-based agents may provide new weapons in the battle against multidrug-resistant pathogens.”

The clay deposit is situated on Heiltsuk First Nation’s traditional territory, 400 kilometres north of Vancouver, Canada, in a shallow five-acre granite basin. The 400-million kilogram (400,000 tonne) deposit was formed near the end of the last Ice Age, approximately 10,000 years ago.

Local First Nations people have used the clay for centuries for its therapeutic properties—anecdotal reports cite its effectiveness for ulcerative colitis, duodenal ulcer, arthritis, neuritis, phlebitis, skin irritation, and burns.

“We’re fortunate to be able to partner with UBC on this significant research program” said Lawrence Lund, president of Kisameet Glacial Clay, a business formed to market cosmetic and medicinal products derived from the clay. “We hope it will lead to the development of a novel and safe antimicrobial that can be added to the diminished arsenal for the fight against the ESKAPE pathogens and other infection-related health issues plaguing the planet.”

In the in vitro testing conducted by Davies and UBC researcher Shekooh Behroozian, clay suspended in water killed 16 strains of ESKAPE bacteria samples from sources including Vancouver General Hospital, St. Paul’s Hospital, and the University of British Columbia’s wastewater treatment pilot plant.

No toxic side effects have been reported in the human use of the clay, and the next stage in clinical evaluation would involve detailed clinical studies and toxicity testing. Loretta Li, with UBC’s Department of Civil Engineering, is conducting mineralogical and chemical analyses of the clay as well. MITACS, Kisameet Glacial Clay Inc. and the Tally Fund supported the work.

Kisameet Bay, British Columbia.

Shovel of clay from Kisameet Bay, British Columbia.

Miniature scaffolding could support fight against superbugs

Tiny molecular scaffolding that joins molecules together could be the key to our battle against antibiotic resistance. Research published in Bioorganic & Medicinal Chemistry Letters shows that carbon nanodot scaffolding assembled with small molecules called polyamines can kill some dangerous drug-resistant bacteria, including Acinetobacter baumanii and Klebsiella pneumonia.

According to the World Health Organization, antimicrobial resistance is one of the biggest public health threats we face today; there were about 480,000 new cases of multidrug-resistant tuberculosis in 2013. Standard treatments are failing and there is an urgent need to develop more effective antibiotics.

Scientists working in this area have found that some large positively charged compounds, called polycationic dendrimers, are antimicrobial. The researchers behind the new study, from Winston-Salem State University in the US and Universiti Malaysia Sarawak in Malaysia, have found that  adding similar, but smaller polycationic molecules onto a new kind of material called carbon nanodots makes them even better at killing drug-resistant bacteria.

“We urgently need new and better antimicrobial materials if we are to tackle drug-resistant bacteria,” said Dr Maria Ngu-Schwemlein, lead author of the study from Winston-Salem State University. “Our study shows that carbon nanodots can serve as a molecular scaffold for building antimicrobial materials; it’s exciting because carbon nanodots are relatively easy and cheap to make, they’re non-toxic and soluble in water.”

“Carbon nanodots as molecular scaffolds for development of antimicrobial agents,” by Maria Ngu-Schwemlein, Suk Fun Chin, Ryan Hileman, Chris Drozdowski, Clint Upchurch and April Hargrove (doi: 10.1016/j.bmcl.2016.02.047). It appears in Bioorganic & Medicinal Chemistry Letters, volume 26, (2016)

Carbon nanodots (C-dots) have generated enormous excitement because of their superiority in water solubility, chemical inertness, low toxicity, ease of functionalization and resistance to photobleaching.