You are what you eat, so they say.

As it happens, the trillions of bacteria inhabiting your intestinal tract eat what you eat, turning meals into molecules that affect your gut, immune system and mind. The brain and nervous system, in turn, seem to be able to scan and modulate your gut microbiome.

Premek Bercik and his colleagues untangle the mysteries of this bi-directional relationship.

Bercik — an Associate Professor in the Division of Gastroenterology and Director of the Clinical Motility lab at McMaster University, in Hamilton, Ontario — studies gut disorders such as Celiac disease and Irritable Bowel Syndrome (IBS), and the links between gut bacteria, bowel inflammation and affective disorders such as depression and anxiety.

Listen to the GPM‘s conversation with Premek in today’s podcast. Click on the button above or go here.

Gut bacteria have numerous tricks up their sleeves. Virtuosic metabolisers of the meat, carbs, fiber and fats we feed them, those bacteria generate molecules that modulate our immune system, stimulate neurons in the walls of our intestinal tract or travel straight to mood centres in our brain. Among these, neurotransmitters such as serotonin and histamine.

Bacteria also stimulate the vagus nerve, the longest nerve in the body, connecting the brain stem and the walls of the gut. The beneficial effects of bacterial supplements (probiotics) may be mediated by the vagus.

In return, the vagus seems to affect gut microbes, scanning those bugs and modifying the composition of bacterial populations. Not surprisingly, the gut microbiome is affected by emotional stress.

Much of what we know about the gut-brain axis has been established in experiments on germ-free mice. Inoculated with stool samples from people with Irritable Bowel Syndrome (IBS), germ-free mice exhibit negative shifts in their own bowel behaviour.

Inoculated with gut samples from people with mood disorders, germ-free mice exhibit their own behavioural shifts.

Drilling down into the mysteries of human gut physiology, Premek Bercik and his team have studied specific strains of ‘good’ and ‘bad’ bacteria. In the former category, Bifidobacterium longum is a well known probiotic.

B. longum NCC3001 reduces patient depression scores and improves gut symptoms, Bercik and his colleagues have found. It also shifts neural activity in brain regions known to be targeted by antidepressants, such as the hippocampus and amygdala.

And, B. longum raises levels of a molecule called brain-derived neurotrophic factor in the hippocampus of mice.

Then there’s a known intestinal ‘bad guy’, Klebsiella aerogenes. Certain strains possess an enzyme that converts the amino acid histidine — found in dietary fermentable fiber — into the inflammatory and pain mediator, histamine. That histamine crosses the intestinal barrier, where it stimulates mast cells, a type of white blood cell. They, in turn, secrete even more histamine.

Consistent with this scenario, people with IBS tend to secrete elevated levels of histamine in their urine.

And, decreased consumption of certain types of fermentable fiber leads to lower urinary histamine and pain relief.

Listen to our conversation with Premek in today’s podcast. Click on the button above or go here.

Land of a Thousand Hills (David Kattenburg)

The 29th anniversary of Rwanda’s 1994 genocide has just come to a close. Over the course of those awful hundred days, between April 7 and July 15, 1994, an estimated eight hundred thousand ethnic Tutsis and a lesser number of their Hutu neighbors were brutally killed by Hutu extremists armed with knives, hoes and machetes.

Over the airwaves, venom flowed. Announcers at Radio-Télévision Mille Collines (from Rwanda’s popular nickname, the ‘Land of a Thousand Hills’), urged listeners to “kill the cockroaches.”

RTLM chiefs distributed cheap pocket radios to stoke the furnace of ethnic hatred. Established in July 1993 by Hutu extremists “to create harmonious development in Rwandan society,” it became the genocide’s key driving force, mobilizing grassroots members of the notorious Interahamwe militia.

This documentary was produced in 2009. All the people you hear have moved on. ‘Gacaca’ courts ended in 2012. Radio Izuba continues to broadcast in Kibungo, eastern Rwanda.

Listen to the story in today’s podcast. Click on the button above or go here.

They’re all the rage. Drones. Every country wants them, packed with sensors, cameras and missiles. Small ones that loiter, drop tear gas or bombs, or crash with a big bang, in kamikaze fashion; big ones that fire missiles, blowing up cars, buildings and people to bits.

All on command from control rooms hundreds, if not thousands of kilometers away.

Now, Canada is in the market for a fleet of its own. Hellfire missiles and laser guided bombs may be on its shopping list, although details are hard to come by. The acquisition process has been opaque from the start.

In 2019, the Canadian Department of National Defense sent an Invitation to Qualify to two drone manufacturers – US weapons firm General Atomics, with its MQ-9B SkyGuardian, a variant of the notorious Reaper, and Quebec-based L3 Technologies, manufacturer of Heron drones, on license to Israeli Aircraft Industries. A formal request for proposals was issued to the two in February 2022.

Lots of countries produce drones. None have more experience field testing them on defenseless, subjugated populations of people than the Israelis.

L3 Technologies and its Heron drones may now be out of the running.

The GPM spoke about Canada’s planned acquisition of a fleet of potentially armed drones with Branka Marijan, a senior researcher at Project Ploughshares, one of Canada’s oldest arms control and disarmament NGOs.

Listen to our conversation with Branka in today’s podcast. Click on the button above or go here.