In the October 13th issue of The Zealotica Daily, we deciphered 9 articles focusing on: colonization resistance, symbiotic-pathogenic interaction, immune diabetes, intestinal mucosal damage, Alzheimer's disease, vitamin B12
<h1 class="pgc-h-arrow-right" data-track="89" >Cell Sub-Journal: Can E. coli resist the invasion of pathogens? Intestinal flora background is key</h1>
Cell Host and Microbe——[21.023]
(1) Comparing two Sessidium mouse models (OMM12, ASF) colonized with different synthetic colonies, it was found that E. coli Mt1B1 can resist Salmonella typhimurium (S.Tm) infection, but its resistance ability varies according to the flora background; (2) this difference is related to the consumption of different carbon sources by E. coli in different flora backgrounds; (3) in the context of ascertained ASF mouse flora susceptible to S.Tm, E. coli uses diverse carbon sources and cannot prevent S.Tm invasion; (4) in OMM12 mice, Indigenous flora can effectively consume free sugars (especially 2 of the Trichotanaceae bacteria), when E. coli competes with S.Tm for carbon-derived galactitol, thus exerting a colonization resistance effect.
【Editor-in-Chief's Comments】
The intestinal flora can exert a colonization resistance effect on pathogens, and the strength of this role depends on the composition of the microbiota itself. A recent study published by Cell Host and Microbe showed that E. coli exerts a colonizing resistance effect against Salmonella in a specific flora background. The study showed that when the host's original intestinal flora can effectively remove free sugars from the intestine, E. coli competes with Salmonella for carbon-derived galactitol, thus preventing Salmonella from encroaching on the ecological niche. （@mildbreeze）
【Original information】
E. coli enhance colonization resistance against Salmonella Typhimurium by competing for galactitol, a context-dependent limiting carbon source
2021-10-04, doi: 10.1016/j.chom.2021.09.004
<h1 class="pgc-h-arrow-right" data-track="97" >Cell sub-journal: Acid-producing Klebsiella resistance to multidrug-resistant Klebsiella pneumonia colonization</h1>
(1) Collected the feces of healthy adults and children, inoculated with multidrug-resistant Klebsiella pneumoniae (Kp) for in vitro culture, and found that there were obvious individual differences in the colonization resistance of the microbiota to Kp; (2) multiple strains of acid-producing Klebella (Ko) were isolated from the Kp-resistant stool and the colonization resistance effect of these bacteria on Kp was verified in mouse models; (3) mechanically, Ko and Kp directly competed with specific carbon sources (including a variety of β-glucosides), CasA, which is involved in the metabolism of β-glucoside, mediates Ko's resistance to Kp; (4) In addition, Ko needs to cooperate with other commensal bacteria to further limit the carbon source in the intestine, thereby establishing effective resistance to Kp.
Intestinal colonization of multidrug-resistant (MDR) bacteria increases the risk of bloodstream infection in susceptible individuals. The study, published by Cell Host and Microbe, identified intestinal symbiotic bacteria that protect the host against colonization of Klebsiella pneumoniae, Klebsiella acid-producing bacteria, or could be used as next-generation probiotics to clear MDR bacteria, and revealed the mechanism by which it exerts a colonization resistance effect. （@mildbreeze）
Klebsiella oxytoca causes colonization resistance against multidrug-resistant K. pneumoniae in the gut via cooperative carbohydrate competition
2021-10-04, doi: 10.1016/j.chom.2021.09.003
<h1 class="pgc-h-arrow-right" data-track="105" >Cell Sub-Journal: Commensal bacteria shape the intestinal environment and affect pathogenic bacteria infections</h1>
(1) Clostridium difficile (Cd) infection in a monobacterial colonized Symbiotic mouse model found that different symbiotic bacteria could have a great influence on the outcome of infection; (2) among them, the double-fermented Clostridium diecysion (Pb) of fermented amino acids can alleviate the disease and improve survival, while the butyric acid-producing Clostridium sardinian (Cs) plays the opposite role; (3) mechanically, these two bacteria have different effects on the pre-infection intestinal nutritional environment (such as Pb consumes nutrients such as ornithine required by Cd, while Cs provides cd with an amine-containing carbon source). Thus differentially regulating cd metabolism, gene regulatory networks and toxin production, and (4) oral Pb can save conventional SPF mice from fatal Cd infection, indicating that it has therapeutic potential.
The study, published by Cell Host and Microbe, used a multi-omics systems biology approach to explore how different Clostridium bifermentans and Clostridium sardiniense bacteria regulate pathogenic colonization, growth, and virulence to affect host survival in mouse models of Clostridium difficile infection. These findings have implications for the development of bacterial therapies against Clostridium difficile. （@mildbreeze）
In vivo commensal control of Clostridioides difficile virulence
2021-10-11, doi: 10.1016/j.chom.2021.09.007
<h1 class="pgc-h-arrow-right" data-track="113" >Nature sub-journal: What are the tricks of symbiotic bacteria to resist Vibrio cholerae colonization? </h1>
Nature Communications——[14.919]
(1) Vibrio cholerae (Vc) kills intestinal symbiotic bacteria through its type VI secretory system (T6SS) to colonize the host gut; (2) however, in vitro studies have found that multiple strains of enterobacteriaceae in humans (such as some Enterobacter sylvioticum and Klebsiella) can resist T6SS violations by Vc by mechanisms that do not rely on immune proteins; (3) multiple strains of Enterobacter purvosa have a more powerful T6SS (T6SS-1), thus winning the competition with pathogenic bacteria such as Vc; (4) Multiple strains of Klebsiella resist the T6SS attack of Vc by forming "armor" with specific capsular polysaccharides covering their surface.
Pathogenic bacteria can promote their own colonization by killing symbiotic bacteria, but many symbiotic bacteria will not sit still. This study, recently published by Nature Communications, reveals how the symbiotic Enterobacteriaceae bacteria in the gut are allegirating against the invasion of Vibrio cholerae. （@mildbreeze）
Human commensal gut Proteobacteria withstand type VI secretion attacks through immunity protein-independent mechanisms
2021-10-01, doi: 10.1038/s41467-021-26041-0
<h1 class="pgc-h-arrow-right" data-track="121" > specific symbiotic bacteria can resist colonization in the intestine by closely related pathogenic bacteria</h1>
Exo——[7.867]
(1) Infection of C3H mice with kanamycin-resistant bacillus rhamnosus (Cr), which results in cr displacement to the cecum during peak infection; (2) after termination of treatment, 65% of mice develop antibiotic-induced Cr symbiotic phenomena (Cr is stable colonization in the cecum + tolerated by the host), but symbiotic Cr can still infect other mice, suggesting that this symbioticization is temporary; (3) the remaining 35% of mice can clear cr colonization in the intestine; (4) from the latter identification of non-malonate citrate bacillus, The bacterium can inhibit cr growth and resist colonization by contact dependence; (5) Therefore, certain commensal bacteria can exert colonization resistance to their closely related pathogenic species.
A recently published study by mBio revealed an antibiotic-induced symbiotic phenomenon in mice and found that the "relative" of the pathogenic bacteria, Bacillus citric acid-free, can exert a colonization resistance effect on the former. （@mildbreeze）
Citrobacter amalonaticus Inhibits the Growth of Citrobacter rodentium in the Gut Lumen
2021-10-05, doi: 10.1128/mBio.02410-21
<h1 class="pgc-h-arrow-right" data-track="129" > domestic team: intestinal flora and metabolic profile characteristics of adult occult immune diabetes</h1>
Diabetes Care——[19.112]
(1) 30 adults with occult autoimmune diabetes mellitus (LADA), 31 cases of classical type 1 diabetes mellitus (T1D), 30 cases of type 2 diabetes mellitus and 29 healthy people were included to analyze the microbiota and metabolites; (2) The structure and composition of the intestinal flora and its metabolites in the LADA group were significantly different from those of other groups, and their SCFA-producing bacteria were the least abundant, and the microbiota structure was more similar to that of T1D patients with positive autoimmune antibody GAD; The 7 serum metabolite modules and 8 fecal metabolite modules differed between the LADA group and other groups, related to autoantibody levels, HbA1c, islet function, or inflammatory factors; (4) intestinal flora and metabolites may be involved in the development of LADA.
Adult occult immune diabetes mellitus (LADA) is an autoimmune disease with clinical and metabolic features similar to classic type 1 and type 2 diabetes and is considered to be in the "gray area" between T1DM and T2DM. The close relationship of the gut microbiota to classic type 1 and type 2 diabetes has been well documented, but the relationship between the gut microbiota and LADA is currently unclear. Yuan Huijuan of Henan Provincial People's Hospital, As the corresponding author, Fang Yuanyuan of Henan Provincial People's Hospital, and Zhang Chenhong of Shanghai Jiao Tong University as the co-first author, published a study in Diabetes Care, which compared and analyzed AGE- and gender-matched LADA patients, classical type 1 and type 2 diabetic patients and healthy people, revealing the characteristics of intestinal flora and fecal and serum metabolites in LADA patients. The study shows that the intestinal flora and metabolites may be involved in the occurrence and development of LADA, and in the future, it should be explored whether the regulation of the intestinal flora and related metabolites can affect LADA in order to seek new treatments. （@mildbreeze）
Characteristics of the Gut Microbiota and Metabolism in Patients With Latent Autoimmune Diabetes in Adults: A Case-Control Study
2021-10-07, doi: 10.2337/dc20-2975
<h1 class="pgc-h-arrow-right" data-track="137" > Mao Shengyong et al.: Sheep studies reveal high grains or damage to the intestinal mucosa? </h1>
mSystems——[6.496]
(1) Study of changes in the microbiome, metabolism and epithelial cell gene expression of sheep cecum by high grain (HG) feeding through sampling at different time points; (2) HG changes to cecal fermentation, including pH decrease and increase in acetic acid and butyrate concentrations; (3) corresponding microbiome changes to acetic acid bacteria such as Brautella spp., Ekmanella and butyric acid-producing bacteria such as anaerobic rods, etc.; (4) HG feeding-related core flora gradually adapts to the intestine, but the specific bacterial species and their genomic levels change over time; (5) Association analysis suggested that HG feeding or promoting catalysis of pyruvate to acetyl-coA and hydrolysis of urea into ammonia triggered an inflammatory response in the mucosa.
As an additional fermentation site to the gastrointestinal tract of ruminants, the cecum usually lacks buffering capacity and the epithelial structure is relatively thin. There are not many studies of related microbial interactions with epithelial function. Mao Shengyong and his team at Nanjing Agricultural University recently elaborated on this at mSystem and provided new insights. (@Good Rain)
Metagenomic Sequencing Reveals that High-Grain Feeding Alters the Composition and Metabolism of Cecal Microbiota and Induces Cecal Mucosal Injury in Sheep
2021-10-05, doi: 10.1128/mSystems.00915-21
<h1 class="pgc-h-arrow-right" data-track="145" > domestic team: oral resveratrol-selenium-peptide nanocomplexes may improve Alzheimer's disease</h1>
ACS Applied Materials & Interfaces——[9.229]
(1) Preparation of resveratrol-selenium-peptide nanocomposites (TGN-Res@SeNPs) to improve res bioavailability and through BBB; (2) TGN-Res@SeNPs can reduce Aβ aggregation in AD model mice induced with aluminum chloride and D-galactose, effectively inhibiting hippocampal Aβ deposition; (3) oral TGN-Res@SeNPs, reducing Aβ-induced reactive oxygen species and increasing the activity of PC12 cells and antioxidant enzymes in vivo; (4) TGN-Res@SeNPs downregulated Aβ-induced neuroinflammation in BV-2 cells and in vivo through the NF-κB/MAPK/Akt signaling pathway; (5) Oral TGN-Res@SeNPs relieve intestinal flora disorders, especially oxidative stress and inflammation-related bacteria.
Alzheimer's disease (AD) is a neurodegenerative disease associated with the deposition of β-amyma (aβ), producing neurotoxicity (oxidative stress and neuroinflammation) and imbalances in the intestinal flora. Zheng Guodong of Jiangxi Agricultural University and Yang Licong of Fuzhou University collaborated in ACS Applied Materials & Interfaces to successfully prepare resveratrol-selenium-peptide nanocomposites (TGN-Res@SeNPs), improve Res bioavailability, reduce Aβ deposition and related oxidative stress and neuroinflammation in AD mice, and regulate intestinal flora. TGN-Res@SeNPs or provides a potential strategy for treating AD. (@Love Choice)
Oral Administration of Resveratrol-Selenium-Peptide Nanocomposites Alleviates Alzheimer's Disease-like Pathogenesis by Inhibiting Aβ Aggregation and Regulating Gut Microbiota
2021-09-27, doi: 10.1021/acsami.1c14818
<h1 class="pgc-h-arrow-right" data-track="153" >Cell Sub-Journal: Vitamin B12 Supplementation or Can Alzheimer's Disease Be Prevented? </h1>
Cell Reports——[9.423]
(1) In β-amyloid (Aβ) transgenic Caenorhabditis elegans, supplementation with vitamin B12 in the diet can inhibit protein toxicity caused by Aβ accumulation; (2) Specifically, vitamin B12 can increase ATP levels, reduce mitochondrial fragmentation, and reduce oxidative stress to alleviate Aβ-induced paralysis and energy loss without affecting the accumulation of Aβ; (3) vitamin B12 supplementation in adulthood also has a protective effect on Aβ-induced protein toxicity later in life; (4) mechanically, Vitamin B12 acts as a cofactor in methionine synthase, exerting a protective effect by influencing the methionine/S-adenosylmethionine cycle.
Diet modification may slow the onset and progression of Alzheimer's disease (AD). A new study published in Cell Reports found that in nematode models with β-amyloid accumulation, vitamin B12 supplementation can affect methionine/S-adenosine methionine cycling by promoting methionine synthesis to inhibit β-amyloid-induced protein toxicity, thereby alleviating paralysis and energy loss. （@szx）
Vitamin B impacts amyloid beta-induced proteotoxicity by regulating the methionine/S-adenosylmethionine cycle
2021-09-28, doi: 10.1016/j.celrep.2021.109753
Thanks to the creators of this issue of the daily: Xu Shuo, Mildbreeze, Hao Yu, Wu Qin, Ji Yu Zhi
Click to read the daily newspaper for the past 10 days:
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10-10 | Adjust the flora anti-fatigue? Controlling diabetes with nutrition? The two Teams in China spoke out strongly
10-09 | New Nature: How gut bacteria degrade gut mucin
10-08 | Today's Science/Cell is all in focus: gut microbiota and cancer
10-07 | Nature Today: Engineered probiotics "turn waste into treasure", or can strengthen the fight against cancer!
10-06 | Liu Haoyu et al. Microbiome: How Lactobacillus reuteri mucus "benefits immunity"
10-05 | NEJM: Clinical good news for new drugs in ulcerative colitis
10-04 | Cell Sub-Issue 25-Page Review Detailed Explanation: Microbiome and Cancer (read with a picture)
10-03 | Why should middle-aged people strengthen dietary fiber? Or a source of power