Three rules of scientific progress:
- Nature: Genetically engineered pig organs were transplanted into experimental monkeys, one of which lived 758 days, paving the way for human experiments on organ transplantation.
- BMJ: Ultra-processed foods such as ice cream, carbonated drinks and prepared dishes may have a deeper impact on human health than thought. What we intuitively feel is metabolic problems such as obesity and cardiovascular disease, and in fact, the deeper impact acts on the regulation of the nervous system, one of which is characterized by addiction.
- The Royal Society Open Science: Frog mating behavior research found that female frogs even evolved pretend to die to avoid reproductive mating.
Female frogs pretend to be dead to avoid mating
Multiple male frogs form a "mating ball" and "die wrap" a female frog
When everything recovers, it is also the animal mating season. For frogs, there is a strong link between mating and death, as some males frantically pounce on potential mates, which can lead to females drowning or crushing to death. To do this, female frogs evolve anti-wolf escape.
A recent study published in the journal Royal Society Open Science showed that female frogs can use evasion to throw off male frogs, are also very good at hiding their identities, and sometimes even avoid mating by faking death.
Author Carolin Dittrich, who investigates the mating habits of frogs, said the discovery was purely accidental.
Most of the time, frogs are alone, except for the intensive mating period of about two weeks each spring, when they meet in pools, hug each other wildly, and reproduce freely.
Between the electric flints, the male will grab a female with the thorny "nuptial pad" on her toe, and the other partner is likely already being grabbed and mated by multiple other males. For frog mating observers, seeing six or seven males wrapped around and "connecting" the same female frog is not new.
In Dietrich's words, the scene looks disgusting, and females caught in the entanglement of the "mating ball" are at risk of death: either drowning or being crushed to death.
Dietrich wondered if males preferred larger females.
She brought wild frogs back to the lab, put two females and a male in a tank, and turned on the camera to record their mating behavior. Soon a shocking picture appeared:
A male frog drags a female frog with open limbs and a stiff, dead body.
After a few minutes, the male frog gave up and turned to another female frog in the tank. After that, the female, who appeared to be dead, woke up and swam away after being hit.
More videos show that after the female frog is caught by the male, 83% will try to roll over the body, 48% will make a sound that mimics the male frog (while also rotating the body), and 33% will be ankylic and immobile, that is, play dead. Females that eventually managed to get rid of accounted for 46% of the total. (The experiment was conducted each time as two females with one male, and a total of 54 females reacted.) ）
Playing dead is a common emergency avoidance method in the animal world, but is generally used to evade predators. It is rare for female frogs to be rigid and immobile to avoid mating, which is used by female salamanders, and male spiders sometimes pretend to be dead to avoid being eaten by their partners.
No one knows what's going through an animal's head when it's motionless, or whether playing dead is a conscious decision
Dr. Dietrich delved into the scientific literature and found several references to such behaviors, one of which is more than 250 years old. Most researchers describe female frogs as passive participants in breeding events, she says, but her work shows that females are not defenseless and have a range of counter-combat, self-protection strategies.
As for the answer to Dietrich's original research goal, "Do males prefer larger females?" the answer is no: "They're not picky at all, they grab whichever they can." ”
Nature: Monkeys transplanted with pig kidneys lived for two years
Recently, the journal Nature published an article reporting on a blockbuster result of xenotransplantation: experimental monkeys that received gene-edited pig kidney transplants survived for an ideal time, with the oldest surviving for more than two years.
The work is led by the US biotech company eGenesis and the Harvard Medical School team. They believe that genetically engineered pig organs have the potential to solve the global organ donor shortage, and that this "extraordinary milestone" achievement "may pave the way for saving countless patients waiting for organ transplants."
The research team used CRISPR tools to edit dozens of genes in donor pig kidneys and transplanted the kidneys into 21 macaques that had their kidneys removed.
They found that macaques typically only survived for 24 days after knocking out 3 genes in pig kidneys that trigger immune rejection in humans; If seven more human genes were inserted that reduce blood clotting, inflammation and other immune responses, the confusion survival time was extended to about 176 days. In combination with treatment that suppressed the immune system, one macaque survived 758 days after transplantation.
It is worth mentioning that Yucatan miniature pigs were selected to provide kidneys because their kidneys are close to adult kidney size when mature; The kidneys transplanted to macaques are only two to three months old, much smaller than the mature size.
Michael Curtis, CEO of eGenesis, said the long-term survival of at least some of the monkeys allowed them to meet FDA requirements that organs survive in animals for at least 12 months before clinical trials in humans can be conducted.
Professor Tatsuo Kawai, another study author from Harvard Medical School, said gene-edited pig organs were expected to perform better in humans than monkeys because "they are better matched".
On the other hand, scientists at the University of Pittsburgh School of Medicine have found that if transplant recipients are given additional dendritic cells from a donor, these cells can "teach" the immune system to accept foreign organs instead of attacking them. This achievement is expected to reduce the risk of rejection of organ transplants in the future.
1/7 adults and 1/8 children are addicted to ultra-processed foods
Recent studies have shown that ultra-processed foods such as ice cream, carbonated drinks, and prepared dishes are linked to health problems, which increase the risk of cancer, obesity, and heart disease. The data shows that global consumption of ultra-processed foods is soaring and now accounts for more than half of the average dietary consumption in the UK and the US.
More worryingly, some people seem to be eating ultra-processed foods in ways that meet the diagnostic criteria for "substance use disorder," or addiction.
Behaviors that meet these criteria include: intense cravings, withdrawal symptoms, lack of control over intake, and – continuing to eat despite knowing the consequences of obesity, binge eating, impaired physical and mental health, and reduced quality of life...
A paper published in the Brithish Medical Journal notes that by analysing 281 studies from 36 different countries, an estimated 14 percent of adults and 12 percent of children suffer from "ultra-processed food addiction."
Researchers say that the changes in extracellular dopamine levels in the striatum of the brain after ingesting refined carbs and fats are similar to those after ingesting addictive substances such as nicotine and alcohol.
Based on behavioral and biological similarities, it is reasonable to assume that foods that provide large amounts of refined carbs or added fat are likely to be addictive; The speed with which they deliver carbs and fats to the intestines may also amplify the addictive effects.
In addition, food additives may also cause addiction, although these additives designed to flavor and improve taste are unlikely to be addictive in themselves, but they seem to significantly affect the digestion and absorption of Neckarus in the intestine.
Ashley Gearhardt, a professor of psychology at the University of Michigan, one of the authors of the paper, said: "The research work provides consistent evidence on the correctness and clinical significance of food addiction. Global health problems can also be expected to improve if the existence of addictive foods is recognized and certain types of foods can be formally classified as addictive foods. ”
Source:
How Female Frogs Fight Off the Mating Ball
Monkey survives for two years with pig kidney in ‘extraordinary milestone’
Addiction to ultra-processed food affects 14% of adults globally, experts say
END
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