Tuesday 31 August 2021

How scared is my baby? Bacteria decide


A new study finds that bacteria are connected to how babies experience fear. In particular, it is an infant's gut microbiome provides clues to neurological development. Moreover, understanding which are the beneficial bacteria could be used to develop a probiotic that could help to monitor and support healthy child.


The study from Michigan State University has investigated the infant's digestive system. This was an attempt to understand why some babies react to the possibility of danger more than others?


The microbiome refers to an ecological niche of bacteria and fungi, plus their genetic material and interactions. One widely studied area is the gut microbiome, especially with the balance of beneficial and potentially harmful organisms. This balance may affect intelligence, development, obesity and other manifestations in later life.


The new research finds that the gut microbiome appears to be different in infants with strong fear responses and infants with milder reactions. Hence it could be possible to develop a new analytical technique to monitor and support healthy neurological development.


The data was drawn from a study of the stool samples of the infants and from observational studies to a potentially scary situation (in this case, an apparent stranger entering ta room while wearing a Halloween mask).


The research, which was based on 30 infants, is seen as particular important in terms of helping to identify those who might go on to develop chronic anxiety and depression later on in life.


Although the study was a pilot, there was sufficient evidence to suggest that some children with particular microbiomes at one month of age tended to be more fearful at one year of age.


It could also be that those infants observed expressing muted fear responses could go on to develop callous, unemotional traits associated with antisocial behavior. This may also become an area of psychological importance.


Furthermore, the content of the microbial community at one year is associated with the size of the amygdala brain region. This is the area of the brain connected with decision making in response to a potential threat.


The research appears in the science journal Nature Communications, with the study titled “Infant gut microbiome composition is associated with non-social fear behavior in a pilot study.”


Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

Monday 30 August 2021

Challenging the hygiene hypothesis


In medicine, the 'hygiene hypothesis' states that early childhood exposure to particular microorganisms protects against allergic diseases by contributing to the development of the immune system.


However, there is a pervading view (public narrative) that Western 21st century society is too hygienic, which means toddlers and children are likely to be less exposed to germs in early life and so become less resistant to allergies.


Exposure to microorganisms in early life is essential for the 'education' of the immune and metabolic systems. Organisms that populate our guts, skin and airways also play an important role in maintaining our health.


There has been a public narrative that hand and domestic hygiene practices, that are essential for stopping exposure to disease-causing pathogens, are also blocking exposure to the beneficial organisms.


Recent research looks at four factors.


1.      The microorganisms found in a modern home are, to a significant degree, not the ones that we need for immunity.

2.      Vaccines, in addition to protecting us from the infection that they target, do a lot more to strengthen our immune systems, so we now know that we do not need to risk death by being exposed to the pathogens.

3.      We now have concrete evidence that the microorganisms of the natural green environment are particularly important for our health; domestic cleaning and hygiene have no bearing on our exposure to the natural environment.

4.      Recent research demonstrates that when epidemiologists find an association between cleaning the home and health problems such as allergies, this is often not caused by the removal of organisms, but rather by exposure of the lungs to cleaning products that cause a type of damage that encourages the development of allergic responses.


To prevent spread of infection, cleaning needs to be targeted to hands and surfaces most often involved in infection transmission. By targeting our cleaning practices, we also limit direct exposure of children to cleaning agents




Graham A.W. Rook, Sally F. Bloomfield. Microbial exposures that establish immunoregulation are compatible with targeted hygiene. Journal of Allergy and Clinical Immunology, 2021; 148 (1): 33 DOI: 10.1016/j.jaci.2021.05.008


Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

Bacteria navigate on surfaces using a 'sense of touch'


Many disease-causing bacteria such as Pseudomonas aeruginosa crawl on surfaces through a walk-like motility known as "twitching." Nanometers-wide filaments called type IV pili are known to power twitching, but scientists ignore which sensory signals coordinate the microbes' movements.


Now, EPFL researchers have found that Pseudomonas bacteria use a mechanism similar to our sense of touch to navigate on surfaces. This study changes the way we think about motility in bacteria.



Scientists have known that cells from humans and other animals can direct themselves in the direction of stiffer or looser surfaces, but it was unclear whether bacteria could also guide their movement based on mechanical force. This is because most studies have focused on identifying mechanisms that guide bacteria to swim towards chemicals such as food, a phenomenon known as chemotaxis.


Research has focused on how bacteria sense and respond to mechanical forces. Previous studies showed that Pseudomonas' pilus works like a harpoon: after it extends and touches a surface, the pilus activates a molecular motor that retracts the filament, thus propelling the cell forward.


To understand what coordinates the pili motors, researchers looked at how individual Pseudomonas bacteria move on surfaces such as the bottom of a laboratory dish. The team suspected that a network of proteins called Chp system regulates twitching, so they analyzed bacteria that lacked different components of the Chp system. Some of these mutant bacteria could barely move as they kept twitching back and forth; others always moved forward, even when they bumped into an obstacle.


By combining fluorescent tags with a microscopy technique that helps to look at single pili in living cells, the researchers found that one messenger protein activates the pili to extend, propelling the cell forward, whereas another protein inhibits the formation of pili at the front of the moving cell. The two opposing messengers aren't found in the same place within the cell.


When bacteria bump into an obstacle such as another cell, the inhibitor allows them to stop and change direction. The ability to sense the surrounding environment is useful when bacteria move as a group helps the microbes to all crawl forward in the same direction.




Marco J. Kühn, Lorenzo Talà, Yuki F. Inclan, Ramiro Patino, Xavier Pierrat, Iscia Vos, Zainebe Al-Mayyah, Henriette Macmillan, Jose Negrete, Joanne N. Engel, Alexandre Persat. Mechanotaxis directs Pseudomonas aeruginosa twitching motility. Proceedings of the National Academy of Sciences, 2021; 118 (30): e2101759118 DOI: 10.1073/pnas.2101759118


Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

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