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PubMedDate not supplied

[Morphological and physiological studies on schizomycetes. Morphogenesis and cytoarchitecture of microbial colony. III. B.subtilis].

The B. subtilis exhibits a morphogenetic mechanism which is different from that observed in the other bacilli examined here. In fact it is distinguishable for the compactness of cellular bundles and the precociousness of the degenerative phenomena which render unrecognizable the internal structure of the colony even before the third day of growth.

Bacillus subtilis↗
PubMedDate not supplied

[Morpho-physiological research on Schizomycetes. Morphogenesis and cytoarchitecture of the microbial colony. I: B. anthracis].

The cytoarchitecture of B. anthracis can be easily studied in serial sections both at the light and at the electron microscope. The morphogenesis of the colony makes clear the peculiar structure of B. anthracis which seems essentially due to the chemical and physical characteristics of the cell envelopes and to the incomplete division of daughter cells. Other factors such as surface tension, humidity, mechanical obstacles and regressive phenomena, seem to be active, in B. anthracis, only since the third day.

Bacillus anthracis↗
PubMed2026

[Intestinal microbiota alterations after digestive tract reconstruction surgery and their impacts on host physiology].

The gut microbiota, acknowledged as the human body's 'second genome', plays a pivotal role in maintaining health. Digestive tract reconstruction surgery profoundly alters the anatomical structure and physiological environment of the gastrointestinal tract, thereby inducing significant shifts in the intestinal microbiota. These microbial changes subsequently influence host physiological functions through metabolic, immune, neuroendocrine, and other pathways. For instance, Roux-en-Y gastric bypass surgery enriches short-chain fatty acid(SCFA)-producing Bacteroides, improving systemic insulin sensitivity. Conversely, pancreaticoduodenectomy leads to a marked enrichment of potential pathobionts such as Klebsiella and Clostridium, which may elevate the risk of infections and tumor recurrence. This review comprehensively summarizes the characteristic changes in the gut microbiota following various digestive tract reconstruction procedures and discusses their multifaceted impacts on host physiology, aiming to provide insights for future experimental research and clinical practice.

Humans↗
PubMed2026

Assessing the diversity and functional profile of the "microbial proteome" in fermented foods.

Fermented foods are staples in diets worldwide and are known for their health benefits. Microorganisms are the key to fermented food production as they convert raw substrates into digestible, nutritious, and health-promoting products. While microbes are essential for fermented food production, their contribution to the dietary protein profile of the final food product in terms of microbial biomass is largely unknown. We analyzed proteins from 17 fermented foods using metaproteomics to identify and quantify microbial and food-derived proteins. We found that microbial proteins contribute up to 11% of the total protein content in fermented foods and comprise as much as 60% of the total number of identified proteins. These microbial proteins included many for central functions in microbial cells, such as glycolysis enzymes, translation machinery, and chaperones, as well as proteins for specialized functions that are important for the ecological niches in food fermentation, such as carbohydrate degrading enzymes and proteases. Some of these microbial proteins, such as proteases, could impact gut physiology. These findings highlight the substantial contribution of microbial proteins to the nutritional and functional profile of fermented foods, which may have important implications for interactions with the gut microbiota and health outcomes.

Fermented Foods↗
PubMed2026

Multi-omics insights into the physiological mechanisms of bile acid accumulation in the gallbladder in brumation-like snakes.

Hibernation/brumation represents an important physiological adaptation for animals to cope with seasonal environmental changes. Field observations suggested increased gallbladder weight in the Five-pacer viper (Deinagkistrodon acutus) during brumation, and our quantitative measurements confirmed this increase together with bile acid accumulation. By integrating a multi-omic approach, this study elucidates the regulatory mechanisms of bile acid accumulation in the gallbladder during brumation. Results showed that taurocholic acid (TCA) and taurodeoxycholic acid (TDCA) were the major components in the gallbladder of the brumation-like group, with significantly elevated concentrations of bile acids, whereas bile acid concentrations in serum and intestinal contents were markedly reduced, indicating suppression of the enterohepatic circulation and consequent accumulation of bile acids in the gallbladder. Hepatic transcriptomic analysis revealed significant downregulation of bile acid synthesis and regulatory genes in brumation-like snakes. In contrast, the alternative synthesis pathway gene sterol 27-hydroxylase (CYP27A1) and some transporter genes were slightly upregulated. Further, some modification genes and regulatory genes showed no significant differences between active and brumation-like states. Gut microbiota analysis demonstrated Akkermansia muciniphila, Bacteroides fragilis, and Citrobacter freundii were more enriched in the active group, which were common microbes related to bile acid metabolism, and the correlation analysis confirmed this relationship. Taken together, these findings indicate that the "physiological bile acid accumulation" observed in snakes during brumation-like state is jointly driven by suppressed hepatic synthesis, reduced enterohepatic circulation, and remodeled microbial community structure. The study provides novel comparative physiological insights into extreme metabolic homeostasis in animals.

Animals↗
PubMed2026

Implications of proteome allocation constraints for understanding interbacterial antagonism.

Bacteria live in dense communities where competition influences the composition and, therefore, the function of these communities. Beyond competing for resources, bacteria engage in antagonism by deploying a range of molecular weapon systems to inhibit and kill other bacteria. Investing in antagonism is expected to incur a fitness trade-off, but the nature of this trade-off at the level of molecular physiology remains underexplained. Applying recent advances about the physiological constraints faced by bacterial cells may help us better understand existing studies and design new investigations into interbacterial antagonism. Bacterial cells face two important constraints: a finite amount of protein and a maximum translation speed for ribosomes. As a result, the only way for a cell to grow faster is to allocate more of its finite proteome to synthesizing ribosomes. A cell choosing to attack competitors must therefore allocate some of its limited proteome budget to antagonistic proteins instead of other functions. Conversely, being attacked and resisting the effects of such attacks also require an investment of proteomic resources. The extent to which proteome allocation constraints influence bacterial physiology is not fully understood; consequently, how these constraints influence interbacterial antagonism has not been investigated. Here, I will discuss how proteome allocation constraints can re-contextualize our existing understanding of the costs of both deploying and resisting attacks and how investigation of these constraints may further our understanding of interbacterial antagonism.

Proteome↗
PubMed1976

[Model of a chronic Vibrio cholerae carrier based on gnotobiotic rats].

Germ-free monoflora (contaminated with nonpathogenic spore-bearing bacillus) and common albino rats (OFA) were infected with V. cholera El Tor, of Ogava and Inaba serological types (6 milliard microbial cells per 1.5 ml of physiological solution per rat). Approximately one week after the infection the number of vibrios reached hundreds of millions per 1 g of feces and persisted at this level for over 100 days (observation period). Newborn rats were infected by natural way from adult vibrio carriers and also became vibrio-carriers. The number of vibrios excretedby the animals which were germ-free and monoflora before the infection was approximately the same. Cholera vibrios perished completely in the enteric tract and were never revealed in the feces of common (control) rats.

Animals↗
PubMed2025

Nutritional modulation of host physiology, behavior, and gut microbiome in the captive rodent Octodon degus.

Diet is a key determinant of health by affecting nutrient metabolism, energy balance, body weight regulation, and mental health. The gut-brain axis is a critical pathway through which dietary factors influence cognitive function and behavior via microbial metabolites. While this relationship has been extensively studied in traditional laboratory models, diet-microbiome-cognition interactions remain largely unexplored in Octodon degus, an emerging model for aging, neurodegeneration, and cognitive research. Here, we compared two widely used rodent diets-LabDiet and Champion-to evaluate their effects on digestive efficiency, behavior, and gut microbiome composition. We also examined the relationships between these variables using piecewise structural equation modeling (pSEM). Our results indicated that LabDiet-fed degus exhibited enhanced nutrient absorption, higher fecal acetic acid levels, and a higher abundance of Actinobacteria (particularly Bifidobacterium), likely driven by its vitamin C supplementation. These animals also showed improved working memory and social motivation, but they displayed increased anxiety-like behavior. In contrast, Champion-fed degus, which consumed a more fiber-diverse, plant-based diet, showed lower anxiety traits and significantly greater gut microbial richness, with higher abundance of Bacteroidota and Tenericutes. Innate behaviors, such as burrowing and nesting, remained unaffected by the diet. SEM analysis revealed that diet explained most of the variance in microbial activity and identified a positive association between acetic acid levels and cognitive performance. This emphasizes a strong relationship among diet, microbiome, and brain function. Overall, our results suggest that dietary composition is a key factor influencing experimental outcomes in degus, with important implications for physiology, cognition, and microbial ecology. Standardizing dietary inputs is essential to ensure reproducibility in behavioral and biomedical studies using this model. Additionally, our results reinforce the microbiome's role as a mediator of diet-driven brain function via SCFAs, underscoring degus as a powerful system for investigating diet-microbiome-neurobehavioral interactions relevant to aging and mental health.

Animals↗
PubMed1979

Systematic bacteriological monitoring of intensive care unit patients: the results of a twelve month study.

The results from the bacteriological monitoring of 464 ITU patients are presented. The specimens analysed include urine, sputa, tracheostomy swabs, central venous pressure line catheter tips, blood cultures, wound drainage fluid, cerebro-spinal fluid, pleural fluid and peritoneal dialysate samples. Guidelines which may be used to differentiate between colonisation and infection and factors, notably those related to antibiotic usage, which are associated with increased risk of infection are described. Certain bacterial and fungal infections which are more peculiar to the compromised host are also discussed.

Bacterial Infections↗
PubMed1978

Quinones as hydrogen carriers for a late step in anaerobic heme biosynthesis in Escherichia coli.

A late step in anaerobic heme synthesis, the oxidation of protoprophyrinogen with fumarate as electron acceptor, was studied in extracts and particles of Escherichia coli mutants deficient in quinones or cytochromes. Mutants specifically deficient in menaquinone did not couple protoporphyrinogen oxidation to fumarate reduction, whereas mutants containing menaquinone but deficient in either ubiquinone or cytochromes exhibited this activity. These findings indicate that this coupled reaction is dependent upon menaquinone as hydrogen carrier but independent of ubiquinone and cytochromes. Other characteristics of this coupled reaction were also studied. The activity was located exclusively in the membrane fraction of cell-free extracts. Coproporphyrinogen III could not replace protoporphyrinogen as substrate. Methylene blue, triphenyl tetrazolium and nitrate, but not nitrite, could replace fumarate as anaerobic hydrogen acceptor. These findings have implications for the mechanism and regulation of microbial heme and chlorophyll synthesis and for the physiology of cytochrome synthesis in anaerobic microorganisms.

Coloring Agents↗
PubMed1978

Bacterial contamination of heat-sterilized, heat-disinfected and chemically-disinfected haemodialysis monitors.

The bacterial contamination of one heat-sterilized, three heat-disinfected and four chemically-disinfected monitor types was evaluated before and after dialysis. All monitor types were contaminated. In the heat-treated monitors the level of contamination varied with the intensity of the heat treatment and the technical design. They were less contaminated than the chemically-disinfected recirculating single-pass monitors. The latter were contaminated to a marginal degree, irrespective of the quality of the water supply. Each monitor showed a characteristic microbial flora, indicating that recontamination occurred from the same persistent focus. Aquired antibiotic resistance characters were rare among the potential human pathogens isolated from the dialysate. The level of contamination during dialysis is determined by a complex of factors, including the mode of disinfection, the technical design of the dialysis equipment, the duration of the dialyses, and the flora of the dialysate.

Anti-Bacterial Agents↗
PubMed2026

Cooperative anaerobic catabolism of chlorinated organic compounds: implications for sustainable bioremediation.

Biodegradation research historically followed a reductionist approach focused on axenic (pure) cultures capable of catabolizing the specific contaminant(s) of interest. While this approach has substantially advanced our understanding of the microbiology, physiology, biochemistry, and genetics of contaminant degradation under laboratory conditions, it does not capture the complexity of natural and engineered environments. During in situ bioremediation, microbiomes are exposed to mixtures of contaminants, and microbial interactions profoundly influence contaminant transformation and fate. In anoxic environments, degradation of chlorinated compounds is often sustained by metabolic cooperation among taxonomically and physiologically distinct microorganisms. Through the exchange of metabolites such as hydrogen, formate, acetate, and other nutrients, microbial populations establish interdependent networks that overcome thermodynamic and physiological constraints, enabling self-sustaining systems of contaminant transformations that would be inefficient or impossible with individual organisms. We highlight examples of microbial interactions that underpin anaerobic catabolism of chlorinated contaminants, including systems resulting in self-sustained anaerobic bioremediation.

Biodegradation, Environmental↗