Tuning self-organization of phosphonium-functionalized polythiophenes for selective recognition and separation of gram-positive and gram-negative bacteria

Human gut bacteria contribute significantly to human health and several studies have evaluated the effects of dietary fibers on human gut bacterial ecology. However, the relationship between different degrees of fiber polymerization and human gut bacteria is unknown. Here, we analyzed three fiber substrates with different degrees of polymerization, namely carboxymethylcellulose, β-glucans, and galactooligosaccharides. To probe the in vitro influence of the degree of polymerization of the fiber on human gut bacteria, we measured the pH, air pressure, and short-chain fatty acid content of fecal fermentation supplemented with these fiber substrates, and sequenced the 16S ribosomal RNA genes of the microbial community in the fiber-treated fermentations. The butyric acid concentration was shown to decline with decreasing degree of polymerization of the fiber. Illumina Miseq sequencing indicated that the degree of polymerization might have an influence on human gut microbial diversity and abundance. Principal coordinate analysis unveiled a relationship between the degree of fiber polymerization and the gut bacterial community. Specific microbiota operational taxonomic units (OTUs) within the genera Escherichia-Shigella, Fusobacterium, and Dorea were proportional to the degree of fiber significantly, whereas OTUs within the genera Bifidobacterium, Streptococcus, and Lactobacillus were inversely correlated with the degree of polymerization. Correlation analysis between the fiber degree of polymerization and gut bacteria may demonstrate the effect of fibers on gut microbiota, and subsequently, on human health.

Peptidoglycan recognition protein (PGRP) is conserved from insects to mammals. In insects, PGRP recognizes bacterial cell wall peptidoglycan (PGN) and activates prophenoloxidase cascade, a part of the insect antimicrobial defense system. Because mammals do not have the prophenoloxidase cascade, its function in mammals is unknown. However, it was suggested that an identical protein (Tag7) was a tumor necrosis factor-like cytokine. Therefore, the aim of this study was to identify the function of PGRP in mammals. Mouse PGRP bound to PGN with fast kinetics and nanomolar affinity (K(d) = 13 nm). The binding was specific for polymeric PGN or Gram-positive bacteria with unmodified PGN, and PGRP did not bind to other cell wall components or Gram-negative bacteria. PGRP mRNA and protein were expressed in neutrophils and bone marrow cells, but not in spleen cells, mononuclear cells, T or B lymphocytes, NK cells, thymocytes, monocytes, and macrophages. PGRP was not a PGN-lytic or a bacteriolytic enzyme, but it inhibited the growth of Gram-positive but not Gram-negative bacteria. PGRP inhibited phagocytosis of Gram-positive bacteria by macrophages, induction of oxidative burst by Gram-positive bacteria in neutrophils, and induction of cytokine production by PGN in macrophages. PGRP had no tumor necrosis factor-like cytotoxicity for mammalian cells, and it was not chemotactic on its own or in combination with PGN. Therefore, mammalian PGRP binds to PGN and Gram-positive bacteria with nanomolar affinity, is expressed in neutrophils, and inhibits growth of bacteria.

Proanthocyanidins, including polymers with both low and high degrees of polymerization, are the focus of intensive research worldwide due to their high antioxidant activity, medicinal applications, and pharmacological properties. However, the nutritional value of these compounds is limited because they readily form complexes with proteins, polysaccharides, and metal ions when consumed. In this study, we examined the effects of proanthocyanidins with different degrees of polymerization on white mice. Twenty-four male white mice were randomly divided into three groups of eight mice each and fed proanthocyanidins with a low degree of polymerization or a high degree of polymerization or a distilled water control via oral gavage over a 56-day period. We examined the effects of these proanthocyanidins on digestive enzyme activity and nutrient absorption. Compared to the control group, the group fed high-polymer proanthocyanidins exhibited a significant reduction in net body mass, total food intake, food utility rate, amylase activity, protease activity, and major nutrient digestibility (p < 0.05), while the group fed low-polymerization proanthocyanidins only exhibited significant reductions in total food intake, α-amylase activity, and apparent digestibility of calcium and zinc (p < 0.05). Therefore, proanthocyanidins with a high degree of polymerization had a greater effect on digestive enzyme activity and nutrient absorption than did those with a low degree of polymerization. This study lays the foundation for elucidating the relationship between procyanidin polymerization and nutrient uptake, with the aim of reducing or eliminating the antinutritional effects of polyphenols.

Shear and elongational flow properties of thermoplastic polyvinyl alcohol melts with different plasticizer contents and degrees of polymerization

Lung epithelial cells express pattern recognition receptors, which react to bacteria. We have evaluated the effect of Gram-positive and Gram-negative bacteria on interleukin-8 (CXCL8) release from epithelial cells and the integrity of the epithelial barrier. Primary cultures of human airway epithelial cells and the epithelial cell line A549 were used, and CXCL8 release was measured after exposure to Gram-negative or Gram-positive bacteria. Epithelial barrier function was assessed in monolayer cultures of A549 cells. Gram-positive bacteria Staphylococcus aureus or Streptococcus pneumoniae, induced release of CXCL8 from human airway epithelial cells. These bacteria also disrupted barrier function in A549 cells, an effect mimicked by CXCL8 and blocked by specific binding antibodies to CXCL8. Gram-negative bacteria Escherichia coli or Pseudomonas aeruginosa induced greater release of CXCL8 than Gram-positive bacteria. However, Gram-negative bacteria did not affect epithelial barrier function directly, but prevented disruption induced by Gram-positive bacteria. These effects of Gram-negative bacteria on barrier function were mimicked by FK565, an agonist of the nucleotide-binding oligomerization domain 1 (NOD1) receptor, but not by the Toll-like receptor (TLR) 4 agonist bacterial lipopolysaccharide. Neither the Gram-negative bacteria nor FK565 blocked CXCL8 release. These data show differential functional responses induced by Gram-negative and Gram-positive bacteria in human lung epithelial cells. The NOD1 receptors may have a role in preventing disruption of the epithelial barrier in lung, during inflammatory states.

How does the degree of inulin polymerization affect the bioaccessibility of bioactive compounds from soursop whey beverage during in vitro gastrointestinal digestion?

The effects of inulin with three different degrees of polymerization (DP) on microbial dietary fiber fermentation were compared in an in vitro simulator of the porcine large bowel. The three inulin isolates had a DP of 15 (from chicory grown in Hokkaido, Japan), and 10 and 24 (from Orafti, Belgium), while cellulose was used as a control. The Lactobacillus level in the DP 10 group at 48 h and bifidobacteria levels in the DP 15 and DP 24 groups at 24 and 48 h were significantly higher than in the carbohydrate-free and cellulose groups. The SCFA concentrations in all the inulin groups were significantly higher than in the carbohydrate-free and cellulose groups at 24 and 48 h. Ammonia nitrogen concentrations in all the inulin groups were significantly lower than those in the carbohydrate-free and cellulose groups at 24 and 48 h. The three different inulin types were fermentable by gut microbiota as indicated by substantial increases in SCFA. In particular, inulin DP 15 exhibited a clear potential to be used as a prebiotic with significant increases in Lactobacillus and Bifidobacterium populations, and concomitantly propionate and butyrate productions than cellulose at the early incubation time. There was a negative correlation between SCFA and ammonia nitrogen concentrations. These results indicate DP 15 product has similar potential as a prebiotic to DP 10 or DP 24 product and showed substantial equivalence to DP 10 and DP 24 products.

Objective To investigate the bacterial spectrum and drug resistance of bone infection after multiple hospitalizations. Methods A retrospective case series study was conducted on 95 patients with bone infection due to injuries admitted in the General Hospital of Shenyang Military Area from January 2009 to December 2016. There were 76 males and 34 females, with an average age of 47 years (range, 17-94 years). Bacterial culture and drug sensitivity tests were performed in 246 specimens of the infection secretions and infected tissues. The bacterial species and drug resistance data of all the specimens were statistically analyzed. The numbers and ratios of Gram-positive bacteria and Gram negative bacteria were counted according to the changes of hospitalization frequency, and the changes of drug resistance of Staphylococcus aureus after repeated hospitalizations were also recorded. Results A total of 110 pathogenic bacteria were isolated, and mixed infection was found in 19% of the bacteria. There were 61 Gram-positive bacteria (55.5%), including 35 Staphylococcus aureus [seven methicillin-resistant staphylococcus (MRSA) strains], accounting for 57% of Gram-positive strains. Other Gram positive bacteria were mainly Enterococcus faecalis and Staphylococcus epidermidis. There were 48 Gram-negative bacteria (43.6%), including 12 Pseudomonas aeruginosa strains, accounting for 25% of Gram-negative strains, nine Klebsiella pneumoniae strains, accounting for 19% of the Gram-negative strains. Staphylococcus aureus had a resistance rate to penicillin of 82%, and the major Gram positive bacteria (Staphylococcus aureus, Enterococcus faecalis, Staphylococcus epidermidis) were all highly sensitive to vancomycin and linezolid. The major Gram-negative bacteria (Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii) were highly resistant to the second generation of cephalosporins and were sensitive to carbapenem antibiotics. In 95 bone infection patients, the ratio of Gram positive bacteria to Gram negative bacteria increased from 0.98 at the first admission to 3 after repeated hospitalizations, and the ratio change was statistically significant (P<0.05). After multiple hospitalizations, the drug resistance of Staphylococcus aureus to gentamicin, ciprofloxacin, levofloxacin, and tetracycline increased gradually. The resistance rate to penicillin was even up to 100%. Conclusions The mixed infection of bone infection is common, among which Staphylococcus aureus and Staphylococcus epidermidis are the main Gram-positive pathogenic bacteria, Pseudomonas aeruginosa and Klebsiella pneumoniae are the main Gram negative pathogenic bacteria. The proportion of Gram-positive bacteria infection increased after multiple hospitalizations and became the major pathogenic bacteria. Penicillin should be avoided in the treatment of Staphylococcus aureus infection in multiple hospitalizations, and gentamicin and ciprofloxacin should be used with caution. Vancomycin or linezolid which is more sensitive is a better option. Key words: Osteomyelitis; Bacteria; Drug susceptibility test

Insight into the stabilization mechanism of emulsions stabilized by Maillard conjugates: Protein hydrolysates-dextrin with different degree of polymerization

Inulin, a non-digestible polysaccharide, has gained attention for its prebiotic properties, particularly in the context of obesity, a condition increasingly understood as a systemic inflammatory state linked to gut microbiota composition. This study investigates the short-term protective effects of inulin with different degrees of polymerization (DPn) against metabolic health deterioration and gut microbiota alterations induced by a high-fat diet (HFD) in Sprague Dawley rats. Inulin treatments with an average DPn of 7, 14, and 27 were administered at 1 g/kg of bodyweight to HFD-fed rats over 21 days. Body weight, systemic glucose levels, and proinflammatory markers were measured to assess metabolic health. Gut microbiota composition was analyzed through 16S rRNA gene sequencing. The results showed that inulin27 significantly reduced total weight gain and systemic glucose levels, suggesting a DPn-specific effect on metabolic health. The study also observed shifts in gut microbial populations, with inulin7 promoting several beneficial taxa from the Bifidobacterium genera, whilst inducing a unique microbial composition compared to medium-chain (DPn 14) and long-chain inulin (DPn: 27). However, the impact of inulin on proinflammatory markers and lipid metabolism parameters was not statistically significant, possibly due to the short study duration. Inulin with a higher DPn has a more pronounced effect on mitigating HFD-induced metabolic health deterioration, whilst inulin7 is particularly effective at inducing healthy microbial shifts. These findings highlight the benefits of inulin as a dietary adjuvant in obesity management and the importance of DPn in optimizing performance.

The leaves and twigs of Viscum album L. (Family: Loranthaceae) were extracted successively with various organic solvents and water. These crude extracts were assessed for antimicrobial activities against three gram positive bacteria that is Staphylococcus aureus, Bacillus subtilis, Enterococcus faecium, five gram negative bacteria that is Escherichia coli,Bordetella bronchisiptica, Salmonella typhi, Pseudomonas aeruginosa, Pseudomonas syringae, one yeast that is Saccharomyces cerevisiae and one filamentous fungusAspergillus flavus by using disc diffusion method. The ethyl acetate, chloroform, ethanol, and methanol crude extracts of selected plant parts had significant antimicrobial activities on both gram positive and gram negative bacteria. The ethyl acetate and methanol crude extracts of leaves and twigs of V. album exhibited prominent activities against gram positive and gram negative bacteria used in comparison to other extracts which had moderate activity against all the tested bacteria. The antimicrobial activities of the crude extracts of the selected plant parts were more active against gram negative bacteria than gram positive bacteria. The standard reference antibiotics, ciprofloxacin (100 um/ml) and nystatin (1500 u/ml) were used as positive control. Key words: Antibacterial, antifungal, disc diffusion, Viscum album, ciprofloxacin, nystatin.

Essential oils and other extracts of plants have evoked have been screened for their potential uses as alternative remedies for the treatment of many infectious diseases. In this context, the aim of this study was to investigate the antibacterial activity of the essential oils from Cinnamon, Thyme, Clove and Geranium against four strains of Gram negative bacteria and two Gram positive bacteria. The in-vitro antimicrobial effects of these essential oils was determined by the disc diffusion method. The Minimum Inhibitory Concentration (MIC) was evaluated by using the broth serial dilution method and Minimum Bactericidal Concentration values (MBC) were defined as the lowest concentration of sample which resulted in ≥99.9% kill of the initial inoculum. The antibacterial effect was deemed bactericidal or bacteriostatic depending on the ratio: MB/CMI. Cinnamon possesses an important antimicrobial activity against all tested microbes, with the inhibition zones ranging from 26 to 32 mm. The essential oils of thyme and Clove showed the antibacterial activity with inhibition zones at 16–22 mm and 16–20 mm, respectively. However, the Geranium essential oil failed to inhibit any of the tested strains. Both gram-positive and gram-negative bacteria were resistant to this essential oil. Results according to the MICs and MBCs revealed that the essential oil from Cinnamon showed the most remarkable bactericidal effect. The essential oil from Cinnamon might be exploited as natural antibiotic for the treatment of several infectious diseases caused by the pathogens germs and conservation agents in the food.

Chromosomal replicases are multiprotein machines comprised of a DNA polymerase, a sliding clamp, and a clamp loader. This study examines replicase components for their ability to be switched between Gram-positive and Gram-negative organisms. These two cell types diverged over 1 billion years ago, and their sequences have diverged widely. Yet the Escherichia coli beta clamp binds directly to Staphylococcus aureus PolC and makes it highly processive, confirming and extending earlier results (Low, R. L., Rashbaum, S. A. , and Cozzarelli, N. R. (1976) J. Biol. Chem. 251, 1311-1325). We have also examined the S. aureus beta clamp. The results show that it functions with S. aureus PolC, but not with E. coli polymerase III core. PolC is a rather potent polymerase by itself and can extend a primer with an intrinsic speed of 80-120 nucleotides per s. Both E. coli beta and S. aureus beta converted PolC to a highly processive polymerase, but surprisingly, beta also increased the intrinsic rate of DNA synthesis to 240-580 nucleotides per s. This finding expands the scope of beta function beyond a simple mechanical tether for processivity to include that of an effector that increases the intrinsic rate of nucleotide incorporation by the polymerase.

Gram-positive and Gram-negative bacteria elicit different patterns of pro-inflammatory cytokines in human monocytes

Raman spectra of Gram-positive and Gram-negative plant bacteria have been measured with micro-Raman spectrometers equipped with 785 and 514.5 nm lasers. The Gram-positive bacteria Microbacterium testaceum, Paenibacillus validus, and Clavibacter michiganensis subsp. michiganensis have strong carotenoid bands in the regions 1155-1157 cm(-1) and 1516-1522 cm(-1) that differentiate them from other tested Gram-negative bacteria. In the Raman spectrum of Gram-positive bacteria Bacillus megaterium excited with 785 nm laser, the Raman bands at 1157 and 1521 cm(-1) are weak in intensity compared to other Gram-positive bacteria, and these bands did not show significant resonance Raman enhancement in the spectrum recorded with 514.5 nm laser excitation. The Gram-positive bacteria could be separated from each other based on the bands associated with the in-phase C=C (v(1)) vibrations of the polyene chain of carotenoids. None of the Gram-negative bacteria tested had carotenoid bands. The bacteria in the genus Xanthomonas have a carotenoid-like pigment, xanthomonadin, identified in Xanthomonas axonopodis pv. dieffenbachiae, and it is a unique Raman marker for the bacteria. The representative bands for xanthomonadin were the C-C stretching (v(2)) vibrations of the polyene chain at 1135-1136 cm(-1) and the in-phase C=C (v(1)) vibrations of the polyene chain at 1529-1531 cm(-1), which were distinct from the carotenoid bands of other tested bacteria. The tyrosine peak in the region 1170-1175 cm(-1) was the only other marker present in Gram-negative bacteria that was absent in all tested Gram-positives. A strong-intensity exopolysaccharide-associated marker at 1551 cm(-1) is a distinguishable feature of Enterobacter cloacae. The Gram-negative Agrobacterium rhizogenes and Ralstonia solanacearum were differentiated from each other and other tested bacteria on the basis of presence or absence and relative intensities of peaks. The principal components analysis (PCA) of the spectra excited with 785 nm laser differentiated the various strains of bacteria based on the unique pigments these bacteria do or do not possess. Raman spectroscopy of diverse plant bacteria that are pathogenic and non-pathogenic to plants, and isolated from plants and soil, indicates the possibilities of using the method in understanding plant-bacterial interactions at the cellular level.