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Frontiers in Microbiology 2021With the increasing number of drug-resistant bacteria, there is an urgent need for new antimicrobial agents, and antimicrobial peptides (AMPs), which exist in the human...
With the increasing number of drug-resistant bacteria, there is an urgent need for new antimicrobial agents, and antimicrobial peptides (AMPs), which exist in the human non-specific immune system, are one of the most promising candidates. It is an effective optimization strategy to modify antimicrobial peptides (AMPs) according to the distribution of amino acids and hydrophobic characteristics. The addition of bacterial pheromones to the N short peptide can increase the ability to recognize bacteria. In this study, we designed and synthesized AMP1-6 by amino acid substitution of mBjAMP1. Additionally, P-6, S-6, and L-6 were designed and synthesized by adding bacterial pheromones based on 1-6. Functional tests showed that the four AMPs had the ability to kill Gram-negative , , and , and Gram-positive and . Additionally, all four AMPs induced permeabilization and depolarization of bacterial cell membranes and increased intracellular reactive oxygen species (ROS) levels. Importantly, they had little or no mammalian cytotoxicity. At the same time, 1-6 and L-6 protected the stability of intestinal flora in and increased the relative abundance of . In summary, our results indicate that the designed AMPs have broad application prospects as a new type of polypeptide antimicrobial agent.
PubMed: 34733268
DOI: 10.3389/fmicb.2021.773076 -
Cureus Sep 2021is a gram-negative, aerobic, rod-shaped bacterium that rarely causes disease in humans. Documented infections can be severe with varying etiologies, often requiring...
is a gram-negative, aerobic, rod-shaped bacterium that rarely causes disease in humans. Documented infections can be severe with varying etiologies, often requiring intensive care. We describe a rare case of bacteremia with in an elderly male, with a comprehensive review of the literature. An 81-year-old Caucasian male presented with bilateral lower leg erythema and drainage but was afebrile. His past medical history included atrial fibrillation, chronic kidney disease, and congestive heart failure. Labs showed leukocytosis and a blood culture was obtained revealing . The pathogen was susceptible to all antibiotics tested and he was successfully treated on cefepime inpatient and a two-week course of ciprofloxacin on discharge. Our case and literature review presents a successful treatment of a rare cause of bacteremia likely stemming from a soft tissue nidus. has a favorable susceptibility profile and the antibiotics preferred differ from , a more common pathogen. Worldwide there have been only 18 other documented cases of infection, all successful and with no mortality. Physicians can confidently utilize usual antibiotics in the treatment of this pathogen despite its rare clinical manifestations.
PubMed: 34659988
DOI: 10.7759/cureus.17777 -
Journal of Hazardous Materials Oct 2021Two-phase partitioning bioreactors (TPPBs) have been extensively used for volatile organic compounds (VOCs) removal. To date, most studies have focused on improving the...
Two-phase partitioning bioreactors (TPPBs) have been extensively used for volatile organic compounds (VOCs) removal. To date, most studies have focused on improving the mass transfer of gas phases/non-aqueous phases (NAPs)/aqueous phases, whereas the NAP/biological phases and gas/biological phases transfer has been neglected. Herein, chitosan was introduced into a TPPB to increase cell surface hydrophobicity (CSH) and improve the n-hexane mass transfer. The performance and stability of the TPPB with chitosan for n-hexane biodegradation were investigated, and it was found out that the TPPB with chitosan achieved maximum removal efficiency and elimination capacity of 80.6% and 26.5 g m h, thereby reaching much higher values than those obtained without chitosan (61.3% and 15.2 g m h). Chitosan not only obvio usly increased cell surface hydrophobicity and cell dry biomass on the surface of silicone oil, but might also allow hydrophobic cells in aqueous phases to directly capture and biodegrade n-hexane, resulting in an obvious improvement of mass transfer from the gas phase to biomass. Stability enhancement was another attractive advantage from chitosan addition. This study might provide a new strategy for the development of TPPB in the hydrophobic VOCs treatment.
Topics: Biodegradation, Environmental; Bioreactors; Chitosan; Hexanes; Pseudomonas mendocina
PubMed: 34171668
DOI: 10.1016/j.jhazmat.2021.126330 -
Mussel Inspired Chemistry and Bacteria Derived Polymers for Oral Mucosal Adhesion and Drug Delivery.Frontiers in Bioengineering and... 2021Ulceration of the oral mucosa is common, can arise at any age and as a consequence of the pain lessens enjoyment and quality of life. Current treatment options often...
Ulceration of the oral mucosa is common, can arise at any age and as a consequence of the pain lessens enjoyment and quality of life. Current treatment options often involve the use of topical corticosteroids with poor drug delivery systems and inadequate contact time. In order to achieve local controlled delivery to the lesion with optimal adhesion, we utilized a simple polydopamine chemistry technique inspired by mussels to replicate their adhesive functionality. This was coupled with production of a group of naturally produced polymers, known as polyhydroxyalkanoates (PHA) as the delivery system. Initial work focused on the synthesis of PHA using CH50; once synthesized and extracted from the bacteria, the PHAs were solvent processed into films. Polydopamine coating was subsequently achieved by immersing the solvent cast film in a polymerized dopamine solution. Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy confirmed functionalization of the PHA films via the presence of amine groups. Further characterization of the samples was carried out via surface energy measurements and Scanning Electron Microscopy (SEM) micrographs for surface topography. An adhesion test via reverse compression testing directly assessed adhesive properties and revealed an increase in polydopamine coated samples. To further identify the effect of surface coating, LIVE/DEAD imaging and Alamar Blue metabolic activity evaluated attachment and proliferation of fibroblasts on the biofilm surfaces, with higher cell growth in favor of the coated samples. Finally, biocompatibility was investigated in a rat model where the polydopamine coated PHA showed less inflammatory response over time compared to uncoated samples with sign of neovascularization. In conclusion, this simple mussel inspired polydopamine chemistry introduces a step change in bio-surface functionalization and holds great promise for the treatment of oral conditions.
PubMed: 34026742
DOI: 10.3389/fbioe.2021.663764 -
Journal of Bioscience and Bioengineering Jul 2021Heterotrophic nitrifying and aerobic denitrifying bacteria that have been widely isolated from complicated activated sludge microflorae demonstrate dominant advantages...
Heterotrophic nitrifying and aerobic denitrifying bacteria that have been widely isolated from complicated activated sludge microflorae demonstrate dominant advantages in simultaneous removal of ammonium and nitrogen oxides under aerobic conditions. However, owing to the need of organic carbon to support bacterial growth, nitrogen removal of actual industrial wastewater with low carbon-to-nitrogen (C/N) ratio remains a challenge. Here, Pseudomonas mendocina Y7 was identified and presented to effectively remove nitrogen of actual refinery wastewater with low C/N ratio. The isolated bacterium showed high removal efficiency of NH-N, NO-N, and NO-N up to about 90% in single (100 mg/L) or mixed (200 mg/L) nitrogen source media at low C/N ratio of 6 when it was cultivated for 12 or 21 h. According to PCR amplification, the heterotrophic nitrification and aerobic denitrification capability of strain Y7 was attributed to the functional genes of amoA, hao, napA, and nirS. In activated sludge process for treating actual refinery wastewater with low C/N ratio, compared to abundant accumulation of NO-N and NO-N only using the activated sludge, strain Y7 significantly improved the removal efficiency of NH‒N and total nitrogen (with influent concentrations of about 40 and 55 mg/L) from about 47% and 22% to about 85% and 73%, respectively, without the accumulation of nitrogen oxides. Microbial community structure analysis revealed that strain Y7 could coexist well with other microorganisms in the activated sludge and maintain highly efficient and steady nitrogen removal in continuous treatment system. This discovery provides a promising treatment approach toward actual nitrogen-rich industrial wastewater.
Topics: Aerobiosis; Bacteria; Carbon; Denitrification; Heterotrophic Processes; Nitrification; Nitrogen; Wastewater; Water Purification
PubMed: 33931317
DOI: 10.1016/j.jbiosc.2021.03.012 -
Applied and Environmental Microbiology May 2021The widely prescribed pharmaceutical metformin and its main metabolite, guanylurea, are currently two of the most common contaminants in surface and wastewater....
The widely prescribed pharmaceutical metformin and its main metabolite, guanylurea, are currently two of the most common contaminants in surface and wastewater. Guanylurea often accumulates and is poorly, if at all, biodegraded in wastewater treatment plants. This study describes strain GU, isolated from a municipal wastewater treatment plant, using guanylurea as its sole nitrogen source. The genome was sequenced with 36-fold coverage and mined to identify guanylurea degradation genes. The gene encoding the enzyme initiating guanylurea metabolism was expressed, and the enzyme was purified and characterized. Guanylurea hydrolase, a newly described enzyme, was shown to transform guanylurea to one equivalent (each) of ammonia and guanidine. Guanidine also supports growth as a sole nitrogen source. Cell yields from growth on limiting concentrations of guanylurea revealed that metabolism releases all four nitrogen atoms. Genes encoding complete metabolic transformation were identified bioinformatically, defining the pathway as follows: guanylurea to guanidine to carboxyguanidine to allophanate to ammonia and carbon dioxide. The first enzyme, guanylurea hydrolase, is a member of the isochorismatase-like hydrolase protein family, which includes biuret hydrolase and triuret hydrolase. Although homologs, the three enzymes show distinct substrate specificities. Pairwise sequence comparisons and the use of sequence similarity networks allowed fine structure discrimination between the three homologous enzymes and provided insights into the evolutionary origins of guanylurea hydrolase. Metformin is a pharmaceutical most prescribed for type 2 diabetes and is now being examined for potential benefits to COVID-19 patients. People taking the drug pass it largely unchanged, and it subsequently enters wastewater treatment plants. Metformin has been known to be metabolized to guanylurea. The levels of guanylurea often exceed that of metformin, leading to the former being considered a "dead-end" metabolite. Metformin and guanylurea are water pollutants of emerging concern, as they persist to reach nontarget aquatic life and humans, the latter if it remains in treated water. The present study has identified a strain that completely degrades guanylurea. The genome was sequenced, and the genes involved in guanylurea metabolism were identified in three widely separated genomic regions. This knowledge advances the idea that guanylurea is not a dead-end product and will allow for bioinformatic identification of the relevant genes in wastewater treatment plant microbiomes and other environments subjected to metagenomic sequencing.
Topics: Ammonia; Bacterial Proteins; Biodegradation, Environmental; Biomineralization; Genome, Bacterial; Guanidine; Hydrolases; Metabolic Networks and Pathways; Metformin; Multigene Family; Pseudomonas mendocina; Substrate Specificity; Urea; Wastewater; Water Pollutants, Chemical
PubMed: 33741630
DOI: 10.1128/AEM.03003-20 -
Genes Jan 2021is an environmental bacterium, rarely isolated in clinical specimens, although it has been described as producing endocarditis and sepsis. Little is known about its...
is an environmental bacterium, rarely isolated in clinical specimens, although it has been described as producing endocarditis and sepsis. Little is known about its genome. Whole genome sequencing can be used to learn about the phylogeny, evolution, or pathogenicity of these isolates. Thus, the aim of this study was to analyze the resistome, virulome, and phylogenetic relationship of two strains, Ps542 and Ps799, isolated from a healthy fecal sample and a lettuce, respectively. Among all of the small number of genomes available in the National Center for Biotechnology Information (NCBI) repository, both strains were placed within one of two well-defined phylogenetic clusters. Both strains lacked antimicrobial resistance genes, but the Ps799 genome showed a MOB family relaxase. Nevertheless, this study revealed that possesses an important number of virulence factors, including a leukotoxin, flagella, pili, and the Type 2 and Type 6 Secretion Systems, that could be responsible for their pathogenesis. More phenotypical and in vivo studies are needed to deepen the association with human infections and the potential pathogenicity.
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Drug Resistance, Microbial; Ducks; Endocarditis; Endodeoxyribonucleases; Feces; Food Microbiology; Genome, Bacterial; Humans; Lactuca; Phylogeny; Pseudomonas mendocina; Sepsis; Virulence Factors; Whole Genome Sequencing
PubMed: 33477842
DOI: 10.3390/genes12010115 -
Journal of Basic Microbiology Apr 2021This study focuses on analyzing the protein expression pattern of intracellular proteins when Pseudomonas mendocina SMSKVR-3 exposed to 300 mM of arsenate to find out...
This study focuses on analyzing the protein expression pattern of intracellular proteins when Pseudomonas mendocina SMSKVR-3 exposed to 300 mM of arsenate to find out the proteins that are overexpressed or exclusively expressed in response to arsenate. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of protein expression at different time intervals showed the highest number of protein bands (14) that are overexpressed at 8 h of the time interval. It was also observed that treatment with at least 200 mM of As(V) is required to induce a difference in protein expression. Two-dimensional (2D)-PAGE analysis of 8-h sample exhibited 146 unique spots, 45 underexpressed, and 46 overexpressed spots in arsenate-treated sample. Based on the highest percent volume and fold change, three unique spots and one overexpressed spot were selected and analyzed by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF/TOF) mass spectrometry (MS) analysis followed by the MASCOT search. These proteins were identified as ribosome-recycling factor (20.13 kDa), polyphosphate:ADP/GDP phosphotransferase (40.88 kDa), ribonuclease P protein component (14.96 kDa) and cobalt-precorrin-5B C(1)-methyltransferase (38.43 kDa) with MASCOT score of 54, 81, 94, and 100, respectively. All of these proteins help the bacteria to overcome arsenate stress.
Topics: Arsenates; Bacterial Proteins; Electrophoresis, Gel, Two-Dimensional; Electrophoresis, Polyacrylamide Gel; Pseudomonas mendocina; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 33448070
DOI: 10.1002/jobm.202000671 -
Journal of Hazardous Materials Feb 2021A cocultivation of the Pseudomonas mendocina with Actinomucor elegans was developed and investigated to improve the biodegradation of polylactic acid/polybutylene...
A cocultivation of the Pseudomonas mendocina with Actinomucor elegans was developed and investigated to improve the biodegradation of polylactic acid/polybutylene adipate-co-terephthalate (PLA/PBAT). And the coculture system could produce an efficient PLA/PBAT-degrading enzymes system to degrade PLA/PBAT films. The results showed that the protease activity (11.50 U/mL) and lipase activity (40.46 U/mL) of the coculture exceeded that of the monoculture (P. mendocina of 7.31 U/mL, A. elegans of 32.47 U/mL). The degradation rate of PLA/PBAT films using the coculture system was 18.95 w% within 5 days, which was considerably higher than that of P. mendocina (12.94 w%) and A. elegans (9.27 w%) individually, suggesting that P. mendocina and A. elegans had synergistic degradation. In addition, P. mendocina and A. elegans could secrete proteases and lipases, respectively, which could catalyze the ester bonds of PLA and PBAT in PLA/PBAT films, respectively, and hydrolyze them into different monomers and oligomers as nutrition sources. Therefore, the PLA/PBAT films could be completely degraded. In this study, the PLA/PBAT films were efficiently degraded in the coculture system for the first time, which significantly improved the biodegradation of PLA/PBAT films.
Topics: Adipates; Coculture Techniques; Mucorales; Phthalic Acids; Polyenes; Polyesters; Pseudomonas mendocina
PubMed: 33264878
DOI: 10.1016/j.jhazmat.2020.123679 -
Cureus Oct 2020is an uncommon pathogen in humans and there are no documented cases of infection associated with central venous catheters. Here we describe a 72-year-old man on...
is an uncommon pathogen in humans and there are no documented cases of infection associated with central venous catheters. Here we describe a 72-year-old man on hemodialysis who presented with a fever and was found to have bacteremia. The only obvious source of infection was the hemodialysis catheter. The isolate was susceptible to all antibiotics tested and he was successfully treated with ciprofloxacin and central venous catheter removal. Patients with chronic medical conditions and vascular devices are at risk for invasive infections with rare Pseudomonas species. As laboratory pathogen detection advances arise, it is possible that additional cases of infections in humans will be identified. Our case provides one example of the successful treatment of bacteremia in a 72-year-old man with a line-associated infection.
PubMed: 33178507
DOI: 10.7759/cureus.10853