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Journal of Environmental Management Jul 2024Composting additives can significantly enhance green waste (GW) composting. However, their effectiveness is limited due to the short action duration of a single-period...
Composite additives regulate physicochemical and microbiological properties in green waste composting: A comparative study of single-period and multi-period addition modes.
Composting additives can significantly enhance green waste (GW) composting. However, their effectiveness is limited due to the short action duration of a single-period addition. Therefore, this study proposes that multi-period additive modes to prolong the action duration, expedite lignocellulose degradation, reduce composting time, and enhance product quality. This study conducted six treatments (T1-T6), introducing a compound additive (BLP) during the mesophilic (MP) and cooling periods (CP). Each treatment consistently maintained 25% total BLP addition of GW dry weight, with variations only in the BLP distribution in different periods. The composition of BLP consists of W: W: W in a ratio of 10:1:40. Specifically, T1 added 25% BLP in CP, T2 added 5% in MP and 20% in CP, T3 added 10% in MP and 15% in CP, T4 added 15% in MP and 10% in CP, T5 added 20% in MP and 5% in CP, and T6 added 25% in MP. In this study, composting temperature, pH value, electrical conductivity, total porosity, the contents of lignin, cellulose, hemicellulose, and nutrient, scanning electron microscopy images, germination index, and the successions of different bacteria and fungi at the phylum and genus levels were detailed. Results showed T4 achieved two thermophilic periods and matured in just 25 days. T4 enhanced lignocellulose degradation rates (lignin: 16-53%, cellulose: 14-23%, hemicellulose: 9-48%) and improved nutrient content. The above results, combined with correlation analysis and structural equation model, indicated that T4 may promote the development of dominant bacteria (Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes) by regulating compost physicochemical properties and facilitate the growth of dominant fungi (Ascomycota and Basidiomycota) by modulating nutrient supply capacity. This ultimately leads to a microbial community structure more conducive to lignocellulose degradation and nutrient preservation. In summary, this study reveals the comprehensive effects of single-period and multi-period addition methods on GW composting, providing a valuable basis for optimizing the use of additives and enhancing the efficiency and quality of GW composting.
PubMed: 38963955
DOI: 10.1016/j.jenvman.2024.121677 -
Sub-cellular Biochemistry 2024Across living organisms, division is necessary for cell survival and passing heritable information to the next generation. For this reason, cell division is highly... (Review)
Review
Across living organisms, division is necessary for cell survival and passing heritable information to the next generation. For this reason, cell division is highly conserved among eukaryotes and prokaryotes. Among the most highly conserved cell division proteins in eukaryotes are tubulin and actin. Tubulin polymerizes to form microtubules, which assemble into cytoskeletal structures in eukaryotes, such as the mitotic spindle that pulls chromatids apart during mitosis. Actin polymerizes to form a morphological framework for the eukaryotic cell, or cytoskeleton, that undergoes reorganization during mitosis. In prokaryotes, two of the most highly conserved cell division proteins are the tubulin homolog FtsZ and the actin homolog FtsA. In this chapter, the functions of the essential bacterial cell division proteins FtsZ and FtsA and their roles in assembly of the divisome at the septum, the site of cell division, will be discussed. In most bacteria, including Escherichia coli, the tubulin homolog FtsZ polymerizes at midcell, and this step is crucial for recruitment of many other proteins to the division site. For this reason, both FtsZ abundance and polymerization are tightly regulated by a variety of proteins. The actin-like FtsA protein polymerizes and tethers FtsZ polymers to the cytoplasmic membrane. Additionally, FtsA interacts with later stage cell division proteins, which are essential for division and for building the new cell wall at the septum. Recent studies have investigated how actin-like polymerization of FtsA on the lipid membrane may impact division, and we will discuss this and other ways that division in bacteria is regulated through FtsZ and FtsA.
Topics: Bacterial Proteins; Cytoskeletal Proteins; Cell Division; Escherichia coli; Escherichia coli Proteins; Bacteria
PubMed: 38963483
DOI: 10.1007/978-3-031-58843-3_4 -
Sub-cellular Biochemistry 2024The copper efflux regulator (CueR) is a classical member of the MerR family of metalloregulators and is common in gram-negative bacteria. Through its C-terminal... (Review)
Review
The copper efflux regulator (CueR) is a classical member of the MerR family of metalloregulators and is common in gram-negative bacteria. Through its C-terminal effector-binding domain, CueR senses cytoplasmic copper ions to regulate the transcription of genes contributing to copper homeostasis, an essential process for survival of all cells. In this chapter, we review the regulatory roles of CueR in the model organism Escherichia coli and the mechanisms for CueR in copper binding, DNA recognition, and interplay with RNA polymerase in regulating transcription. In light of biochemical and structural analyses, we provide molecular details for how CueR represses transcription in the absence of copper ions, how copper ions mediate CueR conformational change to form holo CueR, and how CueR bends and twists promoter DNA to activate transcription. We also characterize the functional domains and key residues involved in these processes. Since CueR is a representative member of the MerR family, elucidating its regulatory mechanisms could help to understand the CueR-like regulators in other organisms and facilitate the understanding of other metalloregulators in the same family.
Topics: Copper; Escherichia coli Proteins; Escherichia coli; Gene Expression Regulation, Bacterial; Transcription, Genetic; Promoter Regions, Genetic; Trans-Activators
PubMed: 38963481
DOI: 10.1007/978-3-031-58843-3_2 -
Journal of Medical Microbiology Jul 2024is an invasive organism that frequently causes severe tissue damage in diabetic foot ulcers. The characterisation of P. aeruginosa strains isolated from diabetic foot...
is an invasive organism that frequently causes severe tissue damage in diabetic foot ulcers. The characterisation of P. aeruginosa strains isolated from diabetic foot infections has not been carried out in Tunisia. The aim was to determine the prevalence of isolated from patients with diabetic foot infections (DFIs) in Tunisia and to characterize their resistance, virulence and molecular typing. Patients with DFIs admitted to the diabetes department of the International Hospital Centre of Tunisia, from September 2019 to April 2021, were included in this prospective study. were obtained from the wound swabs, aspiration and soft tissue biopsies during routine clinical care and were confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antimicrobial susceptibility testing, serotyping, integron and OprD characterization, virulence, biofilm production, pigment quantification, elastase activity and molecular typing were analysed in all recovered isolates by phenotypic tests, specific PCRs, sequencing, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Sixteen isolates (16.3 %) were recovered from 98 samples of 78 diabetic patients and were classified into 6 serotypes (O:11 the most frequent), 11 different PFGE patterns and 10 sequence types (three of them new ones). The high-risk clone ST235 was found in two isolates. The highest resistance percentages were observed to netilmicin (69 %) and cefepime (43.8 %). Four multidrug-resistant (MDR) isolates (25 %) were detected, three of them being carbapenem-resistant. The ST235-MDR strain harboured the In51 class 1 integron (). According to the detection of 14 genes involved in virulence or quorum sensing, 5 virulotypes were observed, including 5 -positive, 9 -positive and 2 -positive strains. The gene was truncated by IS insertion sequence in one isolate, and a deletion of 64 bp in the gene was detected in the ST235-MDR strain. Low biofilm, pyoverdine and elastase production were detected in all ; however, the -truncated strain showed a chronic infection phenotype characterized by loss of serotype-specific antigenicity, high production of phenazines and high biofilm formation. Our study demonstrated for the first time the prevalence and the molecular characterization of strains from DFIs in Tunisia, showing a high genetic diversity, moderate antimicrobial resistance, but a high number of virulence-related traits, highlighting their pathological importance.
Topics: Humans; Pseudomonas aeruginosa; Diabetic Foot; Tunisia; Pseudomonas Infections; Male; Female; Middle Aged; Aged; Prospective Studies; Anti-Bacterial Agents; Microbial Sensitivity Tests; Biofilms; Virulence; Multilocus Sequence Typing; Adult; Virulence Factors; Drug Resistance, Multiple, Bacterial; Aged, 80 and over; Prevalence
PubMed: 38963417
DOI: 10.1099/jmm.0.001851 -
Georgian Medical News Apr 2024We report a severe case of a 25-year-old girl presented with complaints of weakness, diarrhoea, vomiting, pain in abdomen and hypotension at Infectious Diseases and... (Review)
Review
We report a severe case of a 25-year-old girl presented with complaints of weakness, diarrhoea, vomiting, pain in abdomen and hypotension at Infectious Diseases and Clinical Immunology Research Center. From history on 25 February till 29 February she was in India and on 1 march this problem started with watery diarrhoea followed by vomiting. She ate pizza with mushroom following which her condition worsened. Stool culture revealed salmonella nontyphi (nonthyphodal Salmonella)and this is leading cause for gastroenteritis, bacteremia and affects several other bodily system. Her condition deteriorated due to the development of ARDS (acute respiratory distress syndrome) and for this she was on mechanical ventilation. Vitec machine was performed, which identified Salmonella typhi murium. Our goal is to manage and treat this patient well by early diagnosis. She was given ceftriaxone, iv fluids and symptomatic treatment but due to resistance meropenem was started and the patient's condition improved. From serology there was no evidence of immunocompromised state so being a severe case of immunocompetent patient this case reflects the importance of timely diagnosis and management together with food safety practices in population. On follow up she was stable and discharged after 3 weeks. Future research studies need to be continued regarding newer strains, effective treatment strategies and diagnostics to prevent morbidity and mortality.
Topics: Humans; Female; Adult; Salmonella Infections; Ceftriaxone; Anti-Bacterial Agents; Respiratory Distress Syndrome; Multiple Organ Failure; Salmonella; Meropenem; Salmonella typhi; Diarrhea
PubMed: 38963211
DOI: No ID Found -
Clinical and Translational Science Jul 2024Plerixafor is a CXCR4 antagonist approved in 2008 by the FDA for hematopoietic stem cell collection. Subsequently, plerixafor has shown promise as a potential...
Plerixafor is a CXCR4 antagonist approved in 2008 by the FDA for hematopoietic stem cell collection. Subsequently, plerixafor has shown promise as a potential pathogen-agnostic immunomodulator in a variety of preclinical animal models. Additionally, investigator-led studies demonstrated plerixafor prevents viral and bacterial infections in patients with WHIM syndrome, a rare immunodeficiency with aberrant CXCR4 signaling. Here, we investigated whether plerixafor could be repurposed to treat sepsis or severe wound infections, either alone or as an adjunct therapy. In a Pseudomonas aeruginosa lipopolysaccharide (LPS)-induced zebrafish sepsis model, plerixafor reduced sepsis mortality and morbidity assessed by tail edema. There was a U-shaped response curve with the greatest effect seen at 0.1 μM concentration. We used Acinetobacter baumannii infection in a neutropenic murine thigh infection model. Plerixafor did not show reduced bacterial growth at 24 h in the mouse thigh model, nor did it amplify the effects of a rifampin antibiotic therapy, in varying regimens. While plerixafor did not mitigate or treat bacterial wound infections in mice, it did reduce sepsis mortality in zebra fish. The observed mortality reduction in our LPS model of zebrafish was consistent with prior research demonstrating a mortality benefit in a murine model of sepsis. However, based on our results, plerixafor is unlikely to be successful as an adjunct therapy for wound infections. Further research is needed to better define the scope of plerixafor as a pathogen-agnostic therapy. Future directions may include the use of longer acting CXCR4 antagonists, biased CXCR4 signaling, and optimization of animal models.
Topics: Animals; Cyclams; Zebrafish; Benzylamines; Sepsis; Heterocyclic Compounds; Mice; Disease Models, Animal; Receptors, CXCR4; Thigh; Acinetobacter Infections; Pseudomonas aeruginosa; Pseudomonas Infections; Female; Lipopolysaccharides; Wound Infection; Anti-Bacterial Agents
PubMed: 38963161
DOI: 10.1111/cts.13876 -
Arhiv Za Higijenu Rada I Toksikologiju Jun 2024Mistakes in translation are mostly associated with toxic effects in the cell due to the production of functionally aberrant and misfolded proteins. However, under...
Mistakes in translation are mostly associated with toxic effects in the cell due to the production of functionally aberrant and misfolded proteins. However, under certain circumstances mistranslation can have beneficial effects and enable cells to preadapt to other stress conditions. Mistranslation may be caused by mistakes made by aminoacyl-tRNA synthetases, essential enzymes that link amino acids to cognate tRNAs. There is an strain expressing isoleucyl-tRNA synthetase mutant variant with inactivated editing domain which produces mistranslated proteomes where valine (Val) and norvaline (Nva) are misincorporated into proteins instead of isoleucine. We compared this strain with the wild-type to determine the effects of such mistranslation on bacterial growth in oxidative stress conditions. When the cells were pre-incubated with 0.75 mmol/L Nva or 1.5 mmol/L Val or Nva and exposed to hydrogen peroxide, no beneficial effect of mistranslation was observed. However, when the editing-deficient strain was cultivated in medium supplemented with 0.75 mmol/L Val up to the early or mid-exponential phase of growth and then exposed to oxidative stress, it slightly outgrew the wild-type grown in the same conditions. Our results therefore show a modest adaptive effect of isoleucine mistranslation on bacterial growth in oxidative stress, but only in specific conditions. This points to a delicate balance between deleterious and beneficial effects of mistranslation.
Topics: Oxidative Stress; Escherichia coli; Protein Biosynthesis; Escherichia coli Proteins; Hydrogen Peroxide
PubMed: 38963138
DOI: 10.2478/aiht-2024-75-3834 -
Gut Microbes 2024The bacterial species () is a highly diverse pathogen containing more than 2600 distinct serovars, which can infect a wide range of animal and human hosts. Recent...
The transcriptional regulation of the horizontally acquired iron uptake system, yersiniabactin and its contribution to oxidative stress tolerance and pathogenicity of globally emerging strains.
The bacterial species () is a highly diverse pathogen containing more than 2600 distinct serovars, which can infect a wide range of animal and human hosts. Recent global emergence of multidrug resistant strains, from serovars Infantis and Muenchen is associated with acquisition of the epidemic megaplasmid, pESI that augments antimicrobial resistance and pathogenicity. One of the main pESI's virulence factors is the potent iron uptake system, yersiniabactin encoded by , and gene cluster. Here we show that yersiniabactin, has an underappreciated distribution among different serovars and subspecies, integrated in their chromosome or carried by different conjugative plasmids, including pESI. While the genetic organization and the coding sequence of the yersiniabactin genes are generally conserved, a 201-bp insertion sequence upstream to , was identified in pESI. Despite this insertion, pESI-encoded yersiniabactin is regulated by YbtA and the ancestral Ferric Uptake Regulator (Fur), which binds directly to the and promoters. Furthermore, we show that yersiniabactin genes are specifically induced during the mid-late logarithmic growth phase and in response to iron-starvation or hydrogen peroxide. Concurring, yersiniabactin was found to play a previously unknown role in oxidative stress tolerance and to enhance intestinal colonization of . Infantis in mice. These results indicate that yersiniabactin contributes to fitness and pathogenicity and is likely to play a role in the rapid dissemination of pESI among globally emerging lineages.
Topics: Animals; Oxidative Stress; Iron; Mice; Bacterial Proteins; Gene Expression Regulation, Bacterial; Salmonella enterica; Virulence; Phenols; Thiazoles; Humans; Salmonella Infections; Gene Transfer, Horizontal; Female; Virulence Factors; Plasmids
PubMed: 38962965
DOI: 10.1080/19490976.2024.2369339 -
Microbial Biotechnology Jul 2024The phage lysin field has done nothing but grow in the last decades. As a result, many different research groups around the world are contributing to the field, often...
The phage lysin field has done nothing but grow in the last decades. As a result, many different research groups around the world are contributing to the field, often with certain methodological differences that pose a challenge to the interpretation and comparison of results. In this work, we present the case study of three Acinetobacter baumannii-targeting phage lysins (wild-type endolysin LysMK34 plus engineered lysins eLysMK34 and 1D10) plus one lysin with broad activity against Gram-positive bacteria (PlySs2) to provide exemplary evidence on the risks of generalization when using one of the most common lysin evaluation assays: the killing assay with resting cells. To that end, we performed killing assays with the aforementioned lysins using hypo-, iso- and hypertonic buffers plus human serum either as the reaction or the dilution medium in a systematic manner. Our findings stress the perils of creating hypotonic conditions or a hypotonic shock during a killing assay, suggesting that hypotonic buffers should be avoided as a test environment or as diluents before plating to avoid overestimation of the killing effect in the assayed conditions. As a conclusion, we suggest that the nature of both the incubation and the dilution buffers should be always clearly identified when reporting killing activity data, and that for experimental consistency the same incubation buffer should be used as a diluent for posterior serial dilution and plating unless explicitly required by the experimental design. In addition, the most appropriate buffer mimicking the final application must be chosen to obtain relevant results.
Topics: Bacteriophages; Acinetobacter baumannii; Osmolar Concentration; Microbial Viability; Buffers; Humans; Viral Proteins; Endopeptidases
PubMed: 38962879
DOI: 10.1111/1751-7915.14513 -
Frontiers in Cellular and Infection... 2024In the battle against multidrug-resistant bacterial infections, ceftazidime- avibactam (CZA) stands as a pivotal defense, particularly against carbapenemresistant (CR)...
INTRODUCTION
In the battle against multidrug-resistant bacterial infections, ceftazidime- avibactam (CZA) stands as a pivotal defense, particularly against carbapenemresistant (CR) Gram-negative pathogens. However, the rise in resistance against this drug poses a significant threat to its effectiveness, highlighting the critical need for in-depth studies about its resistance mechanisms.
METHODS
This research focuses on the genomic characterization of CR- and CZA-resistant (n=26) and (n=34) strains, harboring the blaNDM and/or blaOXA-48-like genes, at a major Lebanese tertiary care medical center, using whole genome sequencing (WGS).
RESULTS
Our findings revealed a notable prevalence of blaNDM in all strains isolates, with 27 of these also harboring blaOXA-48. On the other hand, E. coli strains predominantly carried the blaNDM-5 gene. Whole genome sequencing (WGS) identified a predominance of ST383 among K. pneumoniae strains, which possessed a multi-replicon IncFIB-IncHI1B plasmid harboring the blaNDM-5. Additionally, various Inc group plasmids in across multiple sequence types were found to carry the blaNDM. Similarly, diverse STs of E. coli were observed to carry blaNDM-5 on different plasmids.
DISCUSSION
The study underscores NDM carbapenemases as a paramount resistance mechanism in Lebanon,jeopardizing critical last-resort treatments. It also illuminates the role of varied sequence types and mobile genetic elements in the spread of NDM resistance,stressing the urgent need for strategies to mitigate this threat, especially in nosocomial infections.
Topics: Ceftazidime; Azabicyclo Compounds; Humans; Lebanon; beta-Lactamases; Klebsiella pneumoniae; Whole Genome Sequencing; Anti-Bacterial Agents; Escherichia coli; Carbapenems; Drug Resistance, Multiple, Bacterial; Drug Combinations; Plasmids; Microbial Sensitivity Tests; Gene Transfer, Horizontal; Genome, Bacterial; Carbapenem-Resistant Enterobacteriaceae; Bacterial Proteins; Tertiary Care Centers
PubMed: 38962322
DOI: 10.3389/fcimb.2024.1407246