A Different Tactic
Antibiotics can weaken bacteria's cell wall and its production of certain proteins, therefore destroying the bacteria. But bacteria have developed resistance to most existing antibiotics. These drug resistant microbes make infections worrisome. For example, urinary tract infections would be a deadly ordeal.
The new drug works in a different tactic. It kills the bacteria by inhibiting a key enzyme in its cell membrane. The cell membrane helps the bacteria secrete proteins. As the enzyme is obstructed, proteins then increase more and more in the cell membrane and ultimately result in the membrane's burst.
Gram-negative bacteria are difficult to be killed with antibiotics for its hard-to-penetrate cell membrane. However, the molecule of the new drug can kill off various common gram-negative bacteria which are infectious to humans such as Escherichia coli and Pseudomonas aeruginosa. And it works well against gram-positive bacteria. Bacterial strains with resistance to most antibiotics can also be destroyed by the molecule.
This study was reported September 12 in Nature. As it is tested on cultured cells and mice, additional testing and tweaking needs to be taken before its use in humans, says Peter Smith, coauthor of the study, who is an infectious disease researcher at Genentech, a biotech company based in South San Francisco, Calif.
But if the drug is widely used, bacteria are likely to evolve new resistance as they always do. Although there may be no permanent solutions, the new drug sounds like a perfect treatment by adopting a different tactic, currently.
A Role of Aging
Senescent cells in the brain play a role in dementia. They accumulate but become inactive with age. Culling these cells can protect the brains of mice according to a new study published online September 19 in Nature.
Scientists studied mice with a toxic form of the protein tau in their brains. These accumulated tangles of protein tau are a sign of dementia, as the research suggests.
Molecular biologist Darren Baker of the Mayo Clinic in Rochester, Minn., and his colleagues engineered some mice with a "kill switch" that can destroy senescent cells quickly and therefore prevent the protein tau from accumulating fast.
They found these mutated mice recognize new smells and objects better than those with more senescent cells in their brains. Navitoclax, an anticancer drug targeting senescent cells, also showed protective effects in these mutated mice’s brains.
The researchers suppose that glial cells in the brain may become senescent because of troubled nerve cells—for example, with toxic tau, the senescent glial cells can damage nerve cells in turn by causing even more tau to accumulate.
Although details about glial cells need further study, Mark Mattson, neuroscientist of the National Institute on Aging in Baltimore, says that senescent cells in brain are related to aging.
To find out if destroying senescent cells can slow or even reverse brain damage in animals with clear signs of disease is what Baker and his colleagues plan to study next.
Climate change can fuel Hurricane Florence.
Hurricane Florence may increase its rainfall and size due to warmer sea surface temperatures and more available moisture in the air.
The climate change attribution studies are being conducted to reveal the relation between human-caused climate change and an extreme event, such as a hurricane, a heat wave, or a flood.
Kevin Reed, climate modeler of Stony Brook University in New York, and colleagues model the climate with and without human-created greenhouse gases over the last 100+ years.
Their counterfactual forecast—going back to the initial conditions and removing the signature of climate change—shows that the rainfall of Florence is more than 50 percent heavier somewhere in Carolinas, given the factor of climate change.
Meanwhile, the diameter of Florence is forecasted about 80 kilometers wider than without climate change, which means a bigger storm would surge across a larger area.
Although the forecasts for Florence have changed a lot since the initial conditions were set on September 11, it would be accurate based on the climate attribution study updated with new conditions and more recent data, according to Reed.