Biology

A G-protein-coupled chemoattractant receptor recognizes lipopolysaccharide for bacterial phagocytosis

PLOS Biology (new articles) - Fri, 2018-05-25 23:00

by Miao Pan, Matthew P. Neilson, Alexander M. Grunfeld, Phillip Cruz, Xi Wen, Robert H. Insall, Tian Jin

Phagocytes locate microorganisms via chemotaxis and then consume them using phagocytosis. Dictyostelium amoebas are stereotypical phagocytes that prey on diverse bacteria using both processes. However, as typical phagocytic receptors, such as complement receptors or Fcγ receptors, have not been found in Dictyostelium, it remains mysterious how these cells recognize bacteria. Here, we show that a single G-protein-coupled receptor (GPCR), folic acid receptor 1 (fAR1), simultaneously recognizes the chemoattractant folate and the phagocytic cue lipopolysaccharide (LPS), a major component of bacterial surfaces. Cells lacking fAR1 or its cognate G-proteins are defective in chemotaxis toward folate and phagocytosis of Klebsiella aerogenes. Computational simulations combined with experiments show that responses associated with chemotaxis can also promote engulfment of particles coated with chemoattractants. Finally, the extracellular Venus-Flytrap (VFT) domain of fAR1 acts as the binding site for both folate and LPS. Thus, fAR1 represents a new member of the pattern recognition receptors (PRRs) and mediates signaling from both bacterial surfaces and diffusible chemoattractants to reorganize actin for chemotaxis and phagocytosis.
Categories: Biology, Journals

Unsolved mysteries: How does lipid peroxidation cause ferroptosis?

PLOS Biology (new articles) - Thu, 2018-05-24 23:00

by Huizhong Feng, Brent R. Stockwell

Ferroptosis is a cell death process driven by damage to cell membranes and linked to numerous human diseases. Ferroptosis is caused by loss of activity of the key enzyme that is tasked with repairing oxidative damage to cell membranes—glutathione peroxidase 4 (GPX4). GPX4 normally removes the dangerous products of iron-dependent lipid peroxidation, protecting cell membranes from this type of damage; when GPX4 fails, ferroptosis ensues. Ferroptosis is distinct from apoptosis, necroptosis, necrosis, and other modes of cell death. Several key mysteries regarding how cells die during ferroptosis remain unsolved. First, the drivers of lipid peroxidation are not yet clear. Second, the subcellular location of lethal lipid peroxides remains an outstanding question. Finally, how exactly lipid peroxidation leads to cell death is an unsolved mystery. Answers to these questions will provide insights into the mechanisms of ferroptotic cell death and associated human diseases, as well as new therapeutic strategies for such diseases.
Categories: Biology, Journals

Fixing planet plastic: How we’ll really solve our waste problem

Genetics - Thu, 2018-05-24 15:40
From bag bans to bacterial mulchers, many solutions are touted for the plastic waste crisis. Find out which work – and which don't – in our definitive guide
Categories: Biology

Nine curious colours that shaped the history of art

Genetics - Thu, 2018-05-24 14:00
From purple sea snail milk to arsenic green and a yellow made from urine, we’ve gone to bizarre lengths in our millennia-long quest to create the most vibrant shades
Categories: Biology

Chimp evolution was shaped by sex with their bonobo relatives

Genetics - Thu, 2018-05-24 13:45
Some chimpanzee populations gained useful DNA from interbreeding with bonobos, and one may even have become more gentle and “bonobo-like” in its brain structure and behaviour
Categories: Biology

Mystery ozone-destroying gases linked to badly recycled fridges

Genetics - Thu, 2018-05-24 12:30
Last week we learned a chemical that harms the ozone layer is being emitted in Asia – and now it seems sloppy recycling might be partly to blame
Categories: Biology

How a change in tactics could help autism research

Genetics - Thu, 2018-05-24 12:24
For some, symptoms of autism can hamper their daily lives, but drugs to mitigate these have floundered during trials. Shafali Jeste has an idea of why
Categories: Biology

Brain implant for OCD surprisingly helps alleviate diabetes too

Genetics - Wed, 2018-05-23 21:00
A person who has a brain implant for OCD has had an unexpected side-effect: better blood sugar control. The finding reveals the brain has a role in diabetes
Categories: Biology

We may have got the evolution of our big brains entirely wrong

Genetics - Wed, 2018-05-23 20:00
Many scientists think that our big brains evolved to help us cope with the complexities of social living, but a model suggests it was more to do with finding food and lighting fires
Categories: Biology

Seafood-lovers have more sex and take less time to get pregnant

Genetics - Wed, 2018-05-23 20:00
Couples who eat seafood more than twice a week have more sex and get pregnant quicker, a study of 1000 people has found, although the reason why remains unclear
Categories: Biology

Clouds of plasma let us zoom in on weird flashes from space

Genetics - Wed, 2018-05-23 20:00
Space plasma magnifies the light from a distant pulsar, letting us zoom in on features so small it’s like measuring the width of a hair on the surface of Mars
Categories: Biology

Men more likely to get diabetes if they have overweight wives

Genetics - Wed, 2018-05-23 17:42
In heterosexual relationships, only men are more likely to get diabetes when their partner has a high BMI – perhaps because of gender roles in the home
Categories: Biology

Pink pineapples and healthy fries: The new GM foods made for you

Genetics - Wed, 2018-05-23 17:00
From health benefits to increased flavour and longer shelf-life, discover the new generation of GM foods designed with the consumer in mind
Categories: Biology

Think you’re fully alert? You can’t always tell if you’re tired

Genetics - Wed, 2018-05-23 16:45
How safe is it to drive when you haven’t had much sleep? Just like drinking alcohol, it turns out we’re not always a good judge of how mentally impaired we are
Categories: Biology

World’s most-spoken languages may have arisen in ancient Iran

Genetics - Wed, 2018-05-23 16:30
About 3 billion people speak Indo-European languages like English and Hindustani, and it seems the first such tongue was spoken south of the Caucasus mountains
Categories: Biology

Watch a badminton robot practice its game-winning trick shots

Genetics - Wed, 2018-05-23 16:25
A badminton robot could be the perfect sparring partner for pros. It has superhuman wrist speeds and has even mastered the tricky spin net shot
Categories: Biology

Those GDPR emails should stop soon, but our data nightmare won’t

Genetics - Wed, 2018-05-23 15:00
Your inbox is full of pleading emails because the EU’s new data rules come into force this week – but they might not actually do anything to improve your life
Categories: Biology

Minimally conscious people woken with brain zap by their family

Genetics - Wed, 2018-05-23 14:30
Some people, who have been minimally conscious for years, could respond to questions from their loved ones for the first time after treatment with electricity
Categories: Biology

There’s a new kind of superfood – and it’s not what you think

Genetics - Wed, 2018-05-23 14:00
GM foods like good-gluten bread are going on sale, with a range of health benefits to tempt consumers. Will doubters be won over at last?
Categories: Biology

Upend atom! We’ve found a whole new way of doing chemistry

Genetics - Wed, 2018-05-23 14:00
We thought we knew how molecules worked – but the discovery of an entirely unknown class of reactions has forced us to rethink the basics
Categories: Biology