NEW FINDINGS — BACTERIA AND VIRUSES Unraveling maternal microbiota It has long been understood that what pregnant women eat and drink affects their developing child. Now, researchers have discovered another surprising influence: the mother’s
ecule byproducts of metabolism, which are likely influenced by the maternal microbiota. The study identified previously unknown microbi- al compounds in
gut bacteria. The gut microbiome, as it's called, might interact with the developing baby in ways scientists never knew before. In the study, researchers compared two groups of mice: normal moms and moms raised in sterile conditions, having no microbiome. The researchers analyzed gene expression and metabolite concentrations in the brain, intestine, and placenta of fetal mice from each group of moms. The study revealed significant differences in gene activity. Male fetuses seemed more sensitive to maternal microbiota than females. In fetuses from germ-free mice, genes related to the immune system were less active in the intestine. At the same time, the brain exhibited variations in genes linked to nervous system development. The placenta showed altered gene expression related to pregnancy regulation. The researchers concluded that variations in the expression of numerous crucial genes were linked to the concentration of small mol-
fetuses. These compounds' absence or lower concentrations in fetuses from germ-free mouse mothers pointed to their likely role in shaping intestinal, brain, and placental develop- ment. Researchers are now investigating these compounds' in other mammals like piglets and calves. This study may help us understand and prevent diseases like allergies and bowel problems caused by imbalances in gut bacteria in early life. This could lead to new ways to prevent and treat these diseases in the future. n REFERENCE: Husso, A., et al. Impacts of maternal microbiota and microbial metabolites on fetal intestine, brain, and placenta. BMC Biology (2023) 21 (1) pubmed.ncbi.nlm.nih.gov/37794486
Longevity association with gut microbiome For ages, humans have been searching for ways to live longer. Research sug- gests our gut bacteria might play a part. A recent study revealed an association between gut microbiome populations and people over 100, also known as cen- tenarians. The study included a cohort of 1,575 individuals divided into smaller study groups based on age. Researchers
Genome-edited mice get human-like COVID-19 Mice are crucial for studying diseases, but until recently, scientists struggled to create mice that model COVID-19. Previous attempts failed because the mice died immediately upon infection. Researchers
had success by inserting a human gene encoding ACE2 receptor protein into mouse embryonic stem cells. ACE2 receptor acts as a doorway for the SARS-CoV-2 virus to enter cells. The modified mice show similar symptoms and activate the same immune cells as humans. The mouse models open up new potential for COVID-19 treatment and prevention research. Not only will the altered mice speed the rate of COVID-19 drug development, but the humanized ACE2 mice can be crossed with other mice to investigate how COVID-19 infection affects people of advanced age or with diabetes or obesity. Scientists used a new technology called genome writing to add large chunks of DNA, like inserting a whole paragraph instead of a single letter. To insert large sections, in this case, more than 2 million nucleotides, researchers used a new delivery method, mSwAP-IN (mammalian Switching Antibiotic markers Progres- sively for Integration). A marker segment of DNA is inserted near the start of the gene. Then, a second marker with a large section of DNA is inserted near the end of the gene. CRISPR then cut out the old gene and swapped it with the new one, guided by the markers. The method allowed scientists to replace a large portion of the mouse gene with the human version, creating mice that act much more like humans with COVID-19. n REFERENCE: Weimin Zhang, et al. Mouse genome rewriting and tailoring of three important disease loci . Nature (2023) 623, 423–431 doi: 10.1038/s41586-023-06675-4
were particularly interested in the gut microbiome of the 297 centenarians. The microbiome makeup of the four non- centenarian groups was compared with the centenarians, revealing some interesting findings. The gut bacteria of people over 100 looked more like the bacteria of young adults than those of older adults (66-99 years old). While the young adults and centenarians had diverse and healthy bacteria, the older adults had more harmful bacteria and less variety. The centenarian group showed an enhanced presence of beneficial Bacteroides bacteria compared to the older cohort. The study also tracked a subset of 45 centenarians for 1.5 years, documenting microbiome patterns. Individuals with less spe- cies diversity were more likely to experience rapid microbiome changes during aging. This instability is a contributing factor to age-related negative health outcomes. Understanding how microbiomes change over a lifespan is increasingly important as people live longer. n REFERENCE: Pang, S., Chen, X., Lu, Z. et al. Longevity of centenarians is reflected by the gut microbiome with youth-associated signatures. Nat Aging (2023) 3, 436–449. doi.org/10.1038/s43587-023-00389-y
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