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Violacein is a natural pigment, a pyrrolidone, and a bisindole derived from the condensation of two tryptophan molecules, which gives a blue violet color to several gram-negative violacein-producing bacteria. Violacein production provides a competitive advantage against antagonistic species or predators. In addition, the compound has antibacterial, antifungal, antiviral, and antioxidant activities. Several studies on colon, breast, and head and neck cancer lines have already demonstrated the anti-proliferative potential of violacein. Bladder cancer is one of the most common types of cancer in urology. The therapeutic approach is mainly based on surgery, chemotherapy, and immunotherapy. The aim of the present study was to evaluate the anti-proliferative activity of violacein against the human bladder cancer cell lines, HTB4 (T24) and HTB9 (5637), using low-grade and high-grade transitional cell carcinoma models, respectively, which has never been assayed before. For this purpose, the potential violacein anti-proliferative effect on T24 and 5637 cells was evaluated by studying the cell viability, proliferation, cell cycle, and caspase-3 activation. The results showed that violacein had anti-proliferative activity in the two cell lines, which was greater for the second-stage bladder cancer cell line (5637), and a different mode of action against the two cell lines., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022, Spandidos Publications.)

This short communication reports the preliminary results of Fecal Microbial Transplantation (FMT) impact on microbiota, microbial translocation (MT), and immune activation in four recurrent Clostridium difficile infection (R-CDI) patients. After FMT a restore of gut microbiota composition with a significant increase of fecal acetyl-putrescine and spermidine and fecal acetate and butyrate, a decrease of immune activation of T cells CD4+ and CD8+levels, and of LPS binding protein (LBP) level, were observed. Preliminary results indicate that FMT seems to be helpful not only as a CDI radical cure, with an impact on fecal microbiota and metabolome profiles, but also on MT and immune activation.

The present study aimed to characterize the behavior of Bdellovibrio bacteriovorus in the presence of Staphylococcus aureus. B. bacteriovorus was co-cultured with S. aureus or Pseudomonas aeruginosa or Streptococcus mutans, in planktonic and sessile conditions. Co-cultures were studied by Field-Emission Scanning Electron Microscopy (FESEM), Scanning Transmission Electron Microscopy (STEM), turbidimetry, quantitative PCR (qPCR), and sequencing of gene Bd0108 of B. bacteriovorus. Results indicated that B. bacteriovorus comparably inhibited planktonic growth of P. aeruginosa and S. aureus, but not of S. mutans. FESEM and STEM showed that B. bacteriovorus interacts with S. aureus affecting its cell wall and membrane. Sequencing of gene Bd0108 did not reveal any of the mutations that can arise from the host-interaction (hit) locus. Although some Gram-negative species are reported to be B. bacteriovorus prey, it seems that in case of nutrient deficiency this predatory bacterium can also take advantage of some Gram-positive species. B. bacteriovorus behaviour in the presence of S. aureus is relevant for its possible therapeutic use in several pathologies, like cystic fibrosis in which S. aureus and P. aeruginosa frequently coexist as infectious agents.

Aims: The present study aimed to investigate microbial patterns associated with disease progression and coinfection by different Herpesviruses in generalized aggressive periodontitis (GAP)., Methods: Microbiological samples were obtained from active (AS) and non-active (n-AS) sites in 165 subjects affected by GAP and were analyzed for 40 bacterial species by the Checkerboard DNA-DNA Hybridization technique and for Herpes simplex 1 (HSV-1), Human Cytomegalovirus (CMV), and Epstein Bar virus (EBV) by PCR.Common Factor Analysis and Multiple Regression Analysis were applied to disclose specific microbial patterns associated with the three viruses., Results: Herpesviruses were detected in 37.6% of subjects. Detection of each of the searched viruses was associated with specific patterns of subgingival biofilm in AS. Logistic regression analyses evidenced several virus/bacteria associations: i) EBV with Aggregatibacter actinomycetemcomitans ; ii) CMV with A. actinomycetemcomitans , Veillonella parvula, Parvimonas micra and Fusobacterium nucleatum subsp . polymorphum ; iii) HSV-1 with Porphyromonas gingivalis , Tannerella forsythia , Fusobacterium periodonticum and Staphylococcus aureus ., Conclusions: Microbiological data suggest that Herpesviruses are probably not mere spectators of disease progression and that specific patterns of subgingival plaque are correlated with the presence of different Herpesviruses.

Violacein (VIO; 3-[1,2-dihydro-5-(5-hydroxy-1H-indol-3-yl)-2-oxo-3H-pyrrol-3-ylidene]-1,3-dihydro-2H-indol-2-one), an indole-derived purple-colored pigment, produced by a limited number of Gram-negative bacteria species, including Chromobacterium violaceum and Janthinobacterium lividum, has been demonstrated to have anti-cancer activity, as it interferes with survival transduction signaling pathways in different cancer models. Head and neck carcinoma (HNC) represents the sixth most common and one of the most fatal cancers worldwide. We determined whether VIO was able to inhibit head and neck cancer cell growth both in vitro and in vivo. We provide evidence that VIO treatment of human and mouse head and neck cancer cell lines inhibits cell growth and induces autophagy and apoptosis. In fact, VIO treatment increased PARP-1 cleavage, the Bax/Bcl-2 ratio, the inhibition of ERK1 and ERK2 phosphorylation, and the expression of light chain 3-II (LC3-II). Moreover, VIO was able to induce p53 degradation, cytoplasmic nuclear factor kappa B (NF-κB) accumulation, and reactive oxygen species (ROS) production. VIO induced a significant increase in ROS production. VIO administration was safe in BALB/c mice and reduced the growth of transplanted salivary gland cancer cells (SALTO) in vivo and prolonged median survival. Taken together, our results indicate that the treatment of head and neck cancer cells with VIO can be useful in inhibiting in vivo and in vitro cancer cell growth. VIO may represent a suitable tool for the local treatment of HNC in combination with standard therapies.

The microbial ecosystem of the gastrointestinal tract is characterized by a great number of microbial species living in balance by adopting mutualistic strategies. The eubiosis/dysbiosis condition of the gut microbiota strongly influences our healthy and disease status. This review briefly describes microbiota composition and functions, to then focus on eubiosis and dysbiosis status: the two sides of the microbiota.

Liver disease is associated with qualitative and quantitative changes in the intestinal microbiota. In cirrhotic patients the alteration in gut microbiota is characterized by an overgrowth of potentially pathogenic bacteria (i.e., gram negative species) and a decrease in autochthonous familiae. Here we summarize the available literature on the risk of gut dysbiosis in liver cirrhosis and its clinical consequences. We therefore described the features of the complex interaction between gut microbiota and cirrhotic host, the so called "gut-liver axis", with a particular attention to the acquired risk of bacterial translocation, systemic inflammation and the relationship with systemic infections in the cirrhotic patient. Such knowledge might help to develop novel and innovative strategies for the prevention and therapy of gut dysbiosis and its complication in liver cirrhosis.

Achromobacter xylosoxidans is an emerging pathogen increasingly being isolated from respiratory samples of cystic fibrosis (CF) patients. Its role and clinical significance in lung pathogenesis have not yet been clarified. The aim of the present study was to genetically characterize A. xylosoxidans strains isolated from CF patients by use of randomly amplified polymorphic DNA (RAPD) profiles and to look for a possible correlation between RAPD profiles and the patients' clinical features, such as their spirometry values, the presence of concomitant chronic bacterial flora at the time of isolation, and the persistent or intermittent presence of A. xylosoxidans strains. A set of 106 strains of A. xylosoxidans were typed by RAPD analysis, and their profiles were analyzed by agglomerative hierarchical classification (AHC) and associated with the patient characteristics mentioned above by factorial discriminant analysis (FDA). The overall results obtained in this study showed that (i) there is a marked genetic relationship between strains isolated from the same patients at different times, (ii) characteristic RAPD profiles are associated with different predicted classes for forced expiratory volume in 1 s (FEV1%), (iii) some characteristic RAPD profiles are associated with different concomitant chronic flora (CCF) profiles, and (iv) there is a significant division of RAPD profiles into "persistent strains" and "intermittent strains" of A. xylosoxidans. These findings seem to imply that the lung habitats found in CF patients are capable of shaping and selecting the colonizing bacterial flora, as seems to be the case for the A. xylosoxidans strains studied.

Respiratory viruses, including rhinoviruses, frequently promote bacterial opportunistic infections, through mechanisms that still deserve to be investigated in detail. This work was aimed at understanding how a viral infection mostly affecting the upper respiratory tract, such as the common cold, can repeatedly promote opportunistic infections in the lower airways, a site where viral replication is limited. The adhesivity and invasivity of Staphylococcus aureus were evaluated, in permissive and non-permissive cells, infected with Rhinovirus-1b. The role of inflammatory cytokines, and of ICAM-1 overexpression in the Rhinovirus-S. aureus cooperation was evaluated. Rhinovirus-1b enhanced the efficiency of internalisation of S. aureus irrespective of cellular permissivity, even when very low viral multiplicities of infection were used. Experiments performed with UV inactivated and heat inactivated viral particles suggested that this enhancement does not depend upon viral replication, but requires viral adhesion. Experimental data suggest that Rhinovirus-1b can significantly increase the ability of S. aureus to internalise into pneumocytes with a mechanism that involves the virus induced release of IL-6 and IL-8, and the overexpression of ICAM-1. Overall data disclose a possible mechanism through which rhinoviruses can promote bacterial infections in the lower respiratory tract.

The virulence plasmid-carried apy (phoN2) gene of Shigella and related enteroinvasive Escherichia coli (EIEC) encodes apyrase, an ATP-diphosphohydrolase belonging to class A of the non-specific acid phosphatases (A-NSAPs). Apyrase and A-NSAPs share three domains of conserved amino acids (domains D1-D3) containing residues forming the putative active site of apyrase. In spite of their similarity, apyrase and A-NSAPs show different substrate specificity, apyrase being able to hydrolyse nucleotide tri- and diphosphates, but not monophosphates, as well as p-nitrophenyl phosphate (pNPP), while A-NSAPs are also active towards monophosphates and pNPP. In this paper, to get further insights into the structure-function relationship of apyrase, a random and site-directed mutagenesis of the apy gene of EIEC strain HN280 was conducted. Results indicate that amino acids located within the D2 and D3 conserved domains (Ser157 and Arg192, respectively) as well as residues located in the N-terminal (Ser97) and C-terminal (Glu233) domains are required for enzyme activity. Surprisingly, Ala160, located near the D2 domain and considered to be important for enzyme specificity, is required for enzyme activity, as its substitution with Thr led to the inactivation of enzyme activity. Furthermore, residue His116 is involved in apyrase specificity, since the H116L apyrase mutant shows substrate specificity resembling that of A-NSAPs.

The olpA gene of Chryseobacterium meningosepticum, encoding a molecular class C phosphatase, was cloned and expressed in Escherichia coli. The gene encodes a 29-kDa polypeptide containing an amino-terminal signal peptide typical of bacterial membrane lipoproteins. Expression in E. coli results in a functional product that mostly partitions in the outer membrane. A secreted soluble OlpA derivative (sOlpA) lacking the N-terminal cysteine residue for lipid anchoring was produced in E. coli and purified by means of two steps of ion exchange chromatography. Analysis of the kinetic parameters of sOlpA with several organic phosphoesters revealed that the enzyme was able to efficiently hydrolyze nucleotide monophosphates, with a strong preference for 5'-nucleotides and for 3'-AMP. The enzyme was also able to hydrolyze sugar phosphates and beta-glycerol phosphate, although with a lower efficiency, whereas it was apparently inactive against nucleotide di- and triphosphates, diesters, and phytate. OlpA, therefore, can be considered a broad-spectrum nucleotidase with preference for 5'-nucleotides. Its functional behaviour exhibits differences from that of the Haemophilus influenzae OMP P4 lipoprotein, revealing functional heterogeneity among phosphatases of molecular class C.