HemN2 Regulates the Virulence of HYS through 7-Hydroxytropolone Synthesis and Oxidative Stress.

Compared to pathogens and , HYS has stronger virulence towards . However, the underlying mechanisms haven't been fully understood. The heme synthesis system is essential for virulence, and former studies of HemN have focused on the synthesis of heme, while the relationship between HemN and virulence were barely pursued.

Biomimetic synthesis of RPL14B-based CdSe quantum dots for the detection of heavy metal copper ions.

In the present study, an -expressed yeast ribosomal protein was used as a template for synthesizing RPL14B-based CdSe quantum dots the quasi-biosynthesis strategy at low temperature. The synthetic bionic RPL14B-based CdSe quantum dots were characterized using TEM, HRTEM, and EDX spectra, and the results showed that the synthesized quantum dots were CdSe quantum dots with a crystal face spacing of 0.21 and 0.

Insight into the High-Efficiency Benzo(a)pyrene Degradation Ability of BaP3 and Its Application in the Complete Bioremediation of Benzo(a)pyrene.

Polycyclic aromatic hydrocarbons (PAHs) are common carcinogens. Benzo(a)pyrene is one of the most difficult high-molecular-weight (HMW) PAHs to remove. Biodegradation has become an ideal method to eliminate PAH pollutants from the environment.

sp. nov., isolated from soil, exhibiting high-efficiency degradation of benzo(a)pyrene.

A Gram-negative, yellow-pigmented, aerobic and rod-shaped bacterium, designated as strain BaP3, was isolated from the soil. Strain BaP3 grew at 16-37℃ (optimum, 30 °C) and pH 6.0-8.

The Gene of the Phenylacetic Acid (PAA) Catabolic Pathway Branching Point and outside the PAA Catabolon Gene Cluster Are Synergistically Involved in the Biosynthesis of the Iron Scavenger 7-Hydroxytropolone in HYS.

The newly discovered iron scavenger 7-hydroxytropolone (7-HT) is secreted by HYS. In addition to possessing an iron-chelating ability, 7-HT has various other biological activities. However, 7-HT's biosynthetic pathway remains unclear.

Biosynthesis of uniform fluorescent-stable telluride quantum dots in Escherichia coli and its detection of Fe in water.

Quantum dots (QDs) containing zinc (Zn) and tellurium (Te) have low toxicity and excellent optoelectronic properties, which make them ideal fluorescent probes for use in environmental monitoring. However, their size/shape distribution synthesized by existing methods is not as good as that of other nanoparticles, thus limiting their application. Exploring whether this kind of QD can be biosynthesized and whether it can act as a nanoprobe are favorable attempts to expand the synthesis method and the application of QDs.

A Lysogenic Bacteriophage Crossing the Antarctic and Arctic, Representing a New Genus of .

Polar regions tend to support simple food webs, which are vulnerable to phage-induced gene transfer or microbial death. To further investigate phage-host interactions in polar regions and the potential linkage of phage communities between the two poles, we induced the release of a lysogenic phage, vB_PaeM-G11, from sp. D3 isolated from the Antarctic, which formed clear phage plaques on the lawn of sp.

Adaptive Laboratory Evolution Reveals the Selenium Efflux Process To Improve Selenium Tolerance Mediated by the Membrane Sulfite Pump in Saccharomyces cerevisiae.

Selenium (Se) is a micronutrient in most eukaryotes, and Se-enriched yeast is the most common selenium supplement. However, selenium metabolism and transport in yeast have remained unclear, greatly hindering the application of this element. To explore the latent selenium transport and metabolism mechanisms, we performed adaptive laboratory evolution under the selective pressure of sodium selenite and successfully obtained selenium-tolerant yeast strains.

Insight into the Global Negative Regulation of Iron Scavenger 7-HT Biosynthesis by the SigW/RsiW System in Pseudomonas donghuensis HYS.

7-Hydroxytropolone (7-HT) is a unique iron scavenger synthesized by HYS that has various biological activities in addition to functioning as a siderophore. HYS is more pathogenic than toward , an observation that is closely linked to the biosynthesis of 7-HT. The nonfluorescent siderophore () gene cluster is responsible for the orderly biosynthesis of 7-HT and represents a competitive advantage that contributes to the increased survival of HYS; however, the regulatory mechanisms of 7-HT biosynthesis remain unclear.

HYS // Gene Cluster Contributes to Its Pathogenicity toward .

HYS is more virulent than toward but the mechanism underlying virulence is unclear. This study is the first to report that the specific gene cluster / in HYS is involved in the virulence of this strain toward , and there are no reports of GtrA, GtrB and GtrII in any species. The pathogenicity of HYS was evaluated using as a host.

Stress preadaptation and overexpression of rpoS and hfq genes increase stress resistance of Pseudomonas fluorescens ATCC13525.

Pseudomonas fluorescens ATCC13525 is an important growth-promoting rhizobacteria (PGPR) and plant disease biocontrol bacterium. However, due to poor stress resistance, it is prone to be inactivated by preparation, drying and storage. In this study, we investigated the effects of different stress preadaptation methods (2.

Analysis of viral load in different specimen types and serum antibody levels of COVID-19 patients.

Background: COVID-19 has caused a global pandemic and the death toll is increasing. However, there is no definitive information regarding the type of clinical specimens that is the best for SARS-CoV-2 detection, the antibody levels in patients with different duration of disease, and the relationship between antibody level and viral load.

Methods: Nasopharyngeal swabs, anal swabs, saliva, blood, and urine specimens were collected from patients with a course of disease ranging from 7 to 69 days.

Identification of a Novel Cathelicidin from the Genome with Antibacterial Activity by Multiple Mechanisms.

The abuse of antibiotics and the consequent increase of drug-resistant bacteria constitute a serious threat to human health, and new antibiotics are urgently needed. Research shows that antimicrobial peptides produced by natural organisms are potential substitutes for antibiotics. Based on (known as five-pacer viper) genome bioinformatics analysis, we discovered a new cathelicidin antibacterial peptide which was called FP-CATH.

Pseudomonas donghuensis HYS 7-hydroxytropolone contributes to pathogenicity toward Caenorhabditis elegans and is influenced by pantothenic acid.

Pseudomonas donghuensis HYS, a bacterial strain identified from Donghu Lake, has tremendous toxicity toward Caenorhabditis elegans and is characterized by high 7-hydroxytropolone siderophore production. Here, the relationship between pathogenic siderophore production and pantothenic acid was evaluated. The pathogenicity of P.

Inhibition of Autophagy via Lysosomal Impairment Enhances Cytotoxicity of Fullerenol under Starvation Condition.

Autophagy is well-known as a common cellular response to nanomaterials. As one of the most comprehensively studied carbon-based nanomaterials, fullerene and its derivatives have been reported to bring about autophagic features in various cell lines, but little is known about the role of fullerenol (C(OH)) on the modulation of autophagy in human gastric tumor cell line SGC-7901. Fullerenol treatment led to the accumulation of autophagosomes, as evidenced by the increased fluorescent intensity of monodansylcadaverine (MDC) staining cells, an elevated level of LC3 protein, and the observation of auotphagosomes in cytoplasm.

Transformation of Viral Light Particles into Near-Infrared Fluorescence Quantum Dot-Labeled Active Tumor-Targeting Nanovectors for Drug Delivery.

Nanosized oncolytic viral light particles (L-particles), separated from progeny virions, are composed of envelopes and several tegument proteins of viruses, free of nucleocapsids. The noninfectious L-particles experience the same internalization process as mature oncolytic virions, which exhibits great potential to act as targeted therapeutic platforms. However, the clinical applications of L-particle-based theranostic platforms are rare due to the lack of effective methods to transform L-particles into nanovectors.

Absolute quantification of particle number concentration using a digital single particle counting system.

The accurate determination of the molar concentration or the number concentration of particles in a defined volume is important but challenging. Since particle diversity and heterogeneity cannot be ignored in particle quantification, single particle counting has become quite important. However, most methods require standard samples (calibrators) which are usually difficult to obtain.

Pseudomonas donghuensis HYS virulence towards Caenorhabditis elegans is regulated by the Cbr/Crc system.

Pseudomonas donghuensis HYS is the type strain of a recently identified species, P. donghuensis, which has pathogenic potential with an unclear virulence mechanism. In this study, we used Caenorhabditis elegans as a host to explore the virulence mechanism of P.

A Complex Mechanism Involving LysR and TetR/AcrR That Regulates Iron Scavenger Biosynthesis in Pseudomonas donghuensis HYS.

7-Hydroxytropolone (7-HT) is a symmetrical seven-membered heteroatomic ring with a carboxyl group and two hydroxyl groups and was recently reported to be an iron scavenger of HYS. Cluster 1 includes 12 genes related to the synthesis of 7-HT; among these genes, those for two regulators, Orf1 and Orf12, were predicted to regulate 7-HT biosynthesis and to be LysR-type transcriptional regulators (LTTRs) and TetR/AcrR family transcriptional regulators, respectively. Data from real-time quantitative PCR and β-galactosidase and classical siderophore assays indicated that the transcription levels of and , as well as those of crucial genes to , were repressed under high-iron conditions.

ATP synthesis in the energy metabolism pathway: a new perspective for manipulating CdSe quantum dots biosynthesized in .

Due to a growing trend in their biomedical application, biosynthesized nanomaterials are of great interest to researchers nowadays with their biocompatible, low-energy consumption, economic, and tunable characteristics. It is important to understand the mechanism of biosynthesis in order to achieve more efficient applications. Since there are only rare studies on the influences of cellular energy levels on biosynthesis, the influence of energy is often overlooked.

Intrinsic Peroxidase-like Activity of Ficin.

Ficin is classified as a sulfhydryl protease isolated from the latex of fig trees. In most cases, a particular enzyme fits a few types of substrate and catalyzes one type of reaction. In this investigation, we found sufficient proofs for the intrinsic peroxidase-like activity of ficin and designed experiments to examine its effectiveness in a variety of scenarios.

7-Hydroxytropolone produced and utilized as an iron-scavenger by Pseudomonas donghuensis.

Pseudomonas donghuensis can excrete large quantities of iron chelating substances in iron-restricted environments. At least two kinds of iron-chelator can be found in the culture supernatant: fluorescent siderophores pyoverdins, and an ethyl acetate-extractable non-fluorescent substance. The non-fluorescent substance was the dominant contributor to the iron chelating activity of the culture supernatant of P.

Inhibition of autophagy contributes to the toxicity of cadmium telluride quantum dots in Saccharomyces cerevisiae.

Cadmium telluride quantum dots (CdTe QDs) are used as near-infrared probes in biologic and medical applications, but their cytological effects and mechanism of potential toxicity are still unclear. In this study, we evaluated the toxicity of CdTe QDs of different sizes and investigated their mechanism of toxicity in the yeast Saccharomyces cerevisiae. A growth inhibition assay revealed that orange-emitting CdTe (O-CdTe) QDs (half inhibitory concentration [IC50] =59.

Cloning, expression, and characterization of catechol 1,2-dioxygenase from a phenol-degrading Candida tropicalis JH8 strain.

The sequence cato encoding catechol 1,2-dioxygenase from Candida tropicalis JH8 was cloned, sequenced, and expressed in Escherichia coli. The sequence cato contained an ORF of 858 bp encoding a polypeptide of 285 amino acid residues. The recombinant catechol 1,2-dioxygenase exists as a homodimer structure with a subunit molecular mass of 32 KD.