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International Journal of Molecular... Feb 2022Rhamnolipids are becoming an important class of glycolipid biosurfactants. Herein, we describe for the first time the enzymatic synthesis of rhamnose fatty acid esters...
Rhamnolipids are becoming an important class of glycolipid biosurfactants. Herein, we describe for the first time the enzymatic synthesis of rhamnose fatty acid esters by the transesterification of rhamnose with fatty acid vinyl esters, using lipase from as a biocatalyst. The use of this lipase allows excellent catalytic activity in the synthesis of 4--acylrhamnose (99% conversion and full regioselectivity) after 3 h of reaction using tetrahydrofuran (THF) as the reaction media and an excess of vinyl laurate as the acyl donor. The role of reaction conditions, such as temperature, the substrates molar ratio, organic reaction medium and acyl donor chain-length, was studied. Optimum conditions were found using 35 °C, a molar ratio of 1:3 (rhamnose:acyldonor), solvents with a low logP value, and fatty acids with chain lengths from C4 to C18 as acyl donors. In hydrophilic solvents such as THF and acetone, conversions of up to 99-92% were achieved after 3 h of reaction. In a more sustainable solvent such as 2-methyl-THF (2-MeTHF), high conversions were also obtained (86%). Short and medium chain acyl donors (C4-C10) allowed maximum conversions after 3 h, and long chain acyl donors (C12-C18) required longer reactions (5 h) to get 99% conversions. Furthermore, scaled up reactions are feasible without losing catalytic action and regioselectivity. In order to explain enzyme regioselectivity and its ability to accommodate ester chains of different lengths, homology modelling, docking studies and molecular dynamic simulations were performed to explain the behaviour observed.
Topics: Biocatalysis; Enzymes, Immobilized; Esterification; Esters; Fatty Acids; Hydrophobic and Hydrophilic Interactions; Laurates; Lipase; Pseudomonas stutzeri; Rhamnose; Solvents; Vinyl Compounds
PubMed: 35216354
DOI: 10.3390/ijms23042239 -
Microbiology Spectrum Feb 2022Microbes are social organisms that commonly live in sessile biofilms. Spatial patterns of populations within biofilms can be important determinants of community-level...
Microbes are social organisms that commonly live in sessile biofilms. Spatial patterns of populations within biofilms can be important determinants of community-level properties. Spatial intermixing emerging from microbial interaction is one of the best-studied characteristics of spatial patterns. The specific levels of spatial intermixing critically contribute to how the dynamics and functioning of such communities are governed. However, the precise factors that determine spatial patterns and intermixing remain unclear. Here, we investigated the spatial patterning and intermixing of an engineered synthetic consortium composed of two mutualistic Pseudomonas stutzeri strains that degrade salicylate via metabolic cross-feeding. We found that the consortium self-organizes across space to form a previously unreported spatial pattern (here referred to as a 'bubble-burst' pattern) that exhibits a low level of intermixing. Interestingly, when the genes encoding type IV pili were deleted from both strains, a highly intermixed spatial pattern developed and increased the productivity of the entire community. The intermixed pattern was maintained in a robust manner across a wide range of initial ratios between the two strains. Our findings show that the type IV pilus plays a role in mitigating spatial intermixing of different populations in surface-attached microbial communities, with consequences for governing community-level properties. These insights provide tangible clues for the engineering of synthetic microbial systems that perform highly in spatially structured environments. When growing on surfaces, multispecies microbial communities form biofilms that exhibit intriguing spatial patterns. These patterns can significantly affect the overall properties of the community, enabling otherwise impermissible metabolic functions to occur as well as driving the evolutionary and ecological processes acting on communities. The development of these patterns is affected by several drivers, including cell-cell interactions, nutrient levels, density of founding cells, and surface properties. The type IV pilus is commonly found to mediate surface-associated behaviors of microorganisms, but its role on pattern formation within microbial communities is unclear. Here, we report that in a cross-feeding consortium, the type IV pilus affects the spatial intermixing of interacting populations involved in pattern formation and ultimately influences overall community productivity and robustness. This novel insight assists our understanding of the ecological processes of surface-attached microbial communities and suggests a potential strategy for engineering high-performance synthetic microbial communities.
Topics: Bacteria; Bacterial Physiological Phenomena; Fimbriae, Bacterial; Microbial Consortia; Microbial Interactions; Pseudomonas stutzeri; Salicylates; Symbiosis
PubMed: 35171019
DOI: 10.1128/spectrum.01944-21 -
Frontiers in Microbiology 2021is a species complex with extremely broad phenotypic and genotypic diversity. However, very little is known about its diversity, taxonomy and phylogeny at the genomic...
is a species complex with extremely broad phenotypic and genotypic diversity. However, very little is known about its diversity, taxonomy and phylogeny at the genomic scale. To address these issues, we systematically and comprehensively defined the taxonomy and nomenclature for this species complex and explored its genetic diversity using hundreds of sequenced genomes. By combining average nucleotide identity (ANI) evaluation and phylogenetic inference approaches, we identified 123 complex genomes covering at least six well-defined species among all sequenced genomes; of these, 25 genomes represented novel members of this species complex. ANI values of ≥∼95% and digital DNA-DNA hybridization (dDDH) values of ≥∼60% in combination with phylogenomic analysis consistently and robustly supported the division of these strains into 27 genomovars (most likely species to some extent), comprising 16 known and 11 unknown genomovars. We revealed that 12 strains had mistaken taxonomic assignments, while 16 strains without species names can be assigned to the species level within the species complex. We observed an open pan-genome of the complex comprising 13,261 gene families, among which approximately 45% gene families do not match any sequence present in the COG database, and a large proportion of accessory genes. The genome contents experienced extensive genetic gain and loss events, which may be one of the major mechanisms driving diversification within this species complex. Surprisingly, we found that the ectoine biosynthesis gene cluster () was present in all genomes of species complex strains but distributed at very low frequency (43 out of 9548) in other genomes, suggesting a possible origin of the ancestors of species complex in high-osmolarity environments. Collectively, our study highlights the potential of using whole-genome sequences to re-evaluate the current definition of the complex, shedding new light on its genomic diversity and evolutionary history.
PubMed: 35095786
DOI: 10.3389/fmicb.2021.755874 -
The ISME Journal May 2022Spatial self-organization is a hallmark of surface-associated microbial communities that is governed by local environmental conditions and further modified by...
Spatial self-organization is a hallmark of surface-associated microbial communities that is governed by local environmental conditions and further modified by interspecific interactions. Here, we hypothesize that spatial patterns of microbial cell-types can stabilize the composition of cross-feeding microbial communities under fluctuating environmental conditions. We tested this hypothesis by studying the growth and spatial self-organization of microbial co-cultures consisting of two metabolically interacting strains of the bacterium Pseudomonas stutzeri. We inoculated the co-cultures onto agar surfaces and allowed them to expand (i.e. range expansion) while fluctuating environmental conditions that alter the dependency between the two strains. We alternated between anoxic conditions that induce a mutualistic interaction and oxic conditions that induce a competitive interaction. We observed co-occurrence of both strains in rare and highly localized clusters (referred to as "spatial jackpot events") that persist during environmental fluctuations. To resolve the underlying mechanisms for the emergence of spatial jackpot events, we used a mechanistic agent-based mathematical model that resolves growth and dispersal at the scale relevant to individual cells. While co-culture composition varied with the strength of the mutualistic interaction and across environmental fluctuations, the model provides insights into the formation of spatially resolved substrate landscapes with localized niches that support the co-occurrence of the two strains and secure co-culture function. This study highlights that in addition to spatial patterns that emerge in response to environmental fluctuations, localized spatial jackpot events ensure persistence of strains across dynamic conditions.
Topics: Bacteria; Microbiota; Models, Theoretical; Pseudomonas stutzeri
PubMed: 35079136
DOI: 10.1038/s41396-022-01189-9 -
Indian Journal of Microbiology Mar 2022Locusts are known for their herbivorous diet that constitutes a nuisance to agriculture worldwide, in Morocco these insects are considered a real threat and are widely...
Locusts are known for their herbivorous diet that constitutes a nuisance to agriculture worldwide, in Morocco these insects are considered a real threat and are widely distributed in the country. These insects are equipped with a digestive system that allows them to digest huge amounts of plant tissue. To understand the mechanisms allowing this voracity, the current study has focused on the diversity of gut microbiome using biochemical and molecular analysis tools, different bacterial isolates were identified and studied. The present study results showed the presence of four important bacterial families that are present in the intestine of these insects, namely Micrococcaceae, Dermabacteraceae, Bacillaceae, and Pseudomonadaceae. The results of Gram staining showed that 2 of 11 isolates were Gram-negative bacteria, however, only 9 bacterial strains were catalase positive. While, 3 strains ( S12, and S4 and S8) had pectinase activity, while only one strain ( S12) had cellulase activity.
PubMed: 35068611
DOI: 10.1007/s12088-021-00984-w -
Molecules (Basel, Switzerland) Dec 2021The release of pharmaceutical wastewaters in the environment is of great concern due to the presence of persistent organic pollutants with toxic effects on environment...
The release of pharmaceutical wastewaters in the environment is of great concern due to the presence of persistent organic pollutants with toxic effects on environment and human health. Treatment of these wastewaters with microorganisms has gained increasing attention, as they can efficiently biodegrade and remove contaminants from the aqueous environments. In this respect, bacterial immobilization with inorganic nanoparticles provides a number of advantages, in terms of ease of processing, increased concentration of the pollutant in proximity of the cell surface, and long-term reusability. In the present study, MCM-41 mesoporous silica nanoparticles (MSN) were immobilized on a selected bacterial strain to remove alprazolam, a persistent pharmaceutical compound, from contaminated water. First, biodegrading microorganisms were collected from pharmaceutical wastewater, and was isolated as a bacterial strain showing high ability to tolerate and consume alprazolam as the only source for carbon and energy. Then, the ability of MSN-adhered bacteria was assessed to biodegrade alprazolam using quantitative HPLC analysis. The results indicated that after 20 days in optimum conditions, MSN-adhered bacterial cells achieved 96% biodegradation efficiency in comparison to the 87% biodegradation ability of freely suspended cells. Kinetic study showed that the degradation process obeys a first order reaction. In addition, the kinetic constants for the MSN-adhered bacteria were higher than those of the bacteria alone.
Topics: Alprazolam; Biodegradation, Environmental; Humans; Industrial Waste; Kinetics; Nanoparticles; Nanotechnology; Phylogeny; Pseudomonas stutzeri; RNA, Ribosomal, 16S; Thermodynamics; Wastewater
PubMed: 35011469
DOI: 10.3390/molecules27010237 -
Frontiers in Microbiology 2021Pseudomonas species are ubiquitous in nature and include numerous medically, agriculturally and technologically beneficial strains of which the interspecific...
Pseudomonas species are ubiquitous in nature and include numerous medically, agriculturally and technologically beneficial strains of which the interspecific interactions are of great interest for biotechnologies. Specifically, co-cultures containing have been used for bioremediation, biocontrol, aquaculture management and wastewater denitrification. Furthermore, the use of biofilms, in combination with consortia-based approaches, may offer advantages for these processes. Understanding the interspecific interaction within biofilm co-cultures or consortia provides a means for improvement of current technologies. However, the investigation of biofilm-based consortia has been limited. We present an adaptable and scalable method for the analysis of macroscopic interactions (colony morphology, inhibition, and invasion) between colony-forming bacterial strains using an automated printing method followed by analysis of the genes and metabolites involved in the interactions. Using Biofilm Interaction Mapping and Analysis (BIMA), these interactions were investigated between strain RCH2, a denitrifier isolated from chromium (VI) contaminated soil, and 13 other species of pseudomonas isolated from non-contaminated soil. One interaction partner, Pseudomonas fluorescens N1B4 was selected for mutant fitness profiling of a DNA-barcoded mutant library; with this approach four genes of importance were identified and the effects on interactions were evaluated with deletion mutants and mass spectrometry based metabolomics.
PubMed: 34956122
DOI: 10.3389/fmicb.2021.757856 -
Microorganisms Dec 2021Fish gut represents a peculiar ecological niche where bacteria can transit and reside to play vital roles by producing bio-compounds with nutritional, immunomodulatory...
Fish gut represents a peculiar ecological niche where bacteria can transit and reside to play vital roles by producing bio-compounds with nutritional, immunomodulatory and other functions. This complex microbial ecosystem reflects several factors (environment, feeding regimen, fish species, etc.). The objective of the present study was the identification of intestinal microbial strains able to produce molecules called biosurfactants (BSs), which were tested for surface and antibacterial activity in order to select a group of probiotic bacteria for aquaculture use. Forty-two bacterial isolates from the digestive tracts of twenty Mediterranean grey mullets were screened for testing emulsifying (E-24), surface and antibiotic activities. Fifty percent of bacteria, ascribed to , sp., and and were found to be surfactant producers. Of the tested strains, 26.6% exhibited an antibacterial activity against (10.0 ± 0.0-14.5 ± 0.7 mm inhibition zone), and among them, 23.3% of isolates also showed inhibitory activity vs. (10.0 ± 0.0-18.5 ± 0.7 mm inhibition zone) and 6.6% vs. (11.5 ± 0.7-17.5 ± 0.7 mm inhibition zone). According to preliminary chemical analysis, the bioactive compounds are suggested to be ascribed to the class of glycolipids. This works indicated that fish gut is a source of bioactive compounds which deserves to be explored.
PubMed: 34946156
DOI: 10.3390/microorganisms9122555 -
Microorganisms Nov 2021Integrative and conjugative elements (ICEs) are chromosomally integrated self-transmissible mobile genetic elements. Although some ICEs are known to carry genes for the...
A New ICE Subfamily Integrative and Conjugative Element Responsible for Horizontal Transfer of Biphenyl and Salicylic Acid Catabolic Pathway in the PCB-Degrading Strain KF716.
Integrative and conjugative elements (ICEs) are chromosomally integrated self-transmissible mobile genetic elements. Although some ICEs are known to carry genes for the degradation of aromatic compounds, information on their genetic features is limited. We identified a new member of the ICE family carrying biphenyl catabolic genes and salicylic acid catabolic genes from the PCB-degrading strain KF716. The 117-kb ICEKF716 contains common core regions exhibiting homology with those of degradative ICE from B13 and ICE from sp. CIB. A comparison of the gene loci collected from the public database revealed that several putative ICEs from B6-2 JAB1, AN10 and 2A20 had highly conserved core regions with those of ICEKF716, along with the variable region that encodes the catabolic genes for biphenyl, naphthalene, toluene, or phenol. These data indicate that this type of ICE subfamily is ubiquitously distributed within aromatic compound-degrading bacteria. ICEKF716 was transferred from KF716 to PAO1 via a circular extrachromosomal intermediate form. In this study, we describe the structure and genetic features of ICEKF716 compared to other catabolic ICEs.
PubMed: 34946064
DOI: 10.3390/microorganisms9122462 -
SAGE Open Nursing 2021Knowledge management-based nursing care has a positive effect in preventing healthcare associated infections (HAIs). Therefore, nursing professionals can utilize key...
INTRODUCTION
Knowledge management-based nursing care has a positive effect in preventing healthcare associated infections (HAIs). Therefore, nursing professionals can utilize key strategies of knowledge management to support clinical decision making, reorganize nursing actions, and maximize patient outcomes.
OBJECTIVES
The aim of this study was to determine the effect of knowledge management-based nursing care educational training on HAI prevention behavior at the High Care Unit (HCU) of Saiful Anwar Hospital Malang.
METHODS
A quasiexperimental design with a pretest, educational training intervention, and posttest were conducted on 15 nurses in the HCU of Saiful Anwar Hospital Malang, which lasted for 16 days. Furthermore, observation of nursing care documentation, nurses' handwashing compliance, and presence of infection-causing bacteria in the HCU staff and environment (hands rub handle, medical record, and patient's bed) was carried out pre (day 1-7) and post training (day 10-16). Subsequently, educational training related to knowledge management-based nursing care was conducted for 2 days (day 8-9) by the Doktor Mengabdi Team of Universitas Brawijaya.
RESULTS
The knowledge level and completeness of the nursing care documentation in the HCU room significantly increased after the training (< .05). Also, compliance to the six steps five moments of nurses' handwashing increased after the training (> .05). Infection-causing bacteria were found in the HCU environment and staff before and after the training involving , , , , , , and . Therefore, increased knowledge of HCU nurses and complete documentation ( = .890; = .054), increased knowledge of HCU nurses and handwashing compliance ( = .770; = .086), and handwashing compliance and bacterial presence ( = .816; = .084) all had a positive correlation.
CONCLUSION
Knowledge management-based nursing care educational training increased infection prevention behavior in the HCU of Saiful Anwar Hospital Malang.
PubMed: 34869859
DOI: 10.1177/23779608211044601