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There is still an urgent need to develop hydrogels with intelligent antibacterial ability to achieve on-demand treatment of infected wounds and accelerate wound healing by improving the regeneration microenvironment. We proposed a strategy of hydrogel wound dressing with bacteria-responsive self-activating antibacterial property and multiple nanozyme activities to remodel the regeneration microenvironment in order to significantly promote infected wound healing. Specifically, pH-responsive H2O2 self-supplying composite nanozyme (MSCO) and pH/enzyme-sensitive bacteria-responsive triblock micelles encapsulated with lactate oxidase (PPEL) were prepared and encapsulated in hydrogels composed of L-arginine-modified chitosan (CA) and phenylboronic acid-modified oxidized dextran (ODP) to form a cascade bacteria-responsive self-activating antibacterial composite hydrogel platform. The hydrogels respond to multifactorial changes of the bacterial metabolic microenvironment to achieve on-demand antibacterial and biofilm eradication through transformation of bacterial metabolites, and chemodynamic therapy enhanced by nanozyme activity in conjunction with self-driven nitric oxide (NO) release. The composite hydrogel showed 'self-diagnostic' treatment for changes in the wound microenvironment. Through self-activating antibacterial therapy in the infection stage to self-adaptive oxidative stress relief and angiogenesis in the post-infection stage, it promotes wound closure, accelerates wound collagen deposition and angiogenesis, and completely improves the microenvironment of infected wound regeneration, which provides a new method for the design of intelligent wound dressings. [ABSTRACT FROM AUTHOR]

Free radical generation plays a key role in killing bacteria by antibiotics. However, radicals are short-lived and reactive, and thus difficult to detect for the state of the art. Here we use a technique which allows optical nanoscale magnetic resonance imaging (MRI) to detect radical generation on the scale of single bacteria. We demonstrate that the radical generation in Staphylococcus aureus increases in the presence of UV irradiation as well as vancomycin and is dependent on the antibiotic's dose. With a method based on ensembles of nitrogen vacancy (NV) centers in diamond, we were able to follow the radical formation near individual bacteria over the whole duration of the experiment to reveal the dynamics of radical generation. Using this new approach, we observed free radical concentrations within nanoscale voxels around the diamond particles and determined its exact timing depending on the antibiotic dose. Since changes in the response to antibiotics emerge in only a few bacteria of the entire population, such a single-cell approach can prove highly valuable for research into drug resistance. [Display omitted] [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the activity of Hydnophytum formicarum Jack (Ant Plant) tuber extract against Staphylococcus aureus and Escherichia coli and the mode of action of the extract on bacterial responses. The antibacterial activity was determined using agar well diffusion method. Resazurin-based 96-well microdilution method was used to determine the Minimal Inhibitory Concentrations (MIC) of the extract. Mode of action on bacterial death and response patterns to the extract were assessed by flow cytometry using membrane integrity and granularity profiles. The results, based on serial dilution and zones of inhibition against the bacteria, showed that 2,000 µg/well was potent against S. aureus (16.33±1.53 mm) and E. coli (14.33±0.58 mm). For S. aureus, the MIC concentration was 8,000 µg/mL, while 4,000 µg/mL concentration exhibited activity against E. coli. Flow cytometric profiles confirmed loss of intracellular components, followed by death, for both bacteria. Bacterial responses to the extract had consistent dose- and time-dependent behavior. This is the first mode of action study on bacterial responses to H. formicarum tuber extract. The results suggest that the extract of H. formicarum tuber could serve as a source of an initial active ingredient for developing effective medicines to battle infections caused by pathogens. [ABSTRACT FROM AUTHOR]

The present study investigated the variation in surface free energy, adhesion strength, and bacterial attachment during early colonization. Two different sizes of micro dimple textured surface MDS 400 and MDS 200 on Ti6Al4V were fabricated using mechanical micro-milling and studied with an un-textured surface. One polar (water) and dispersive liquid (diiodomethane) were used to study the work of adhesion and surface free energy of both surfaces. The Neumann method and Owen & Wendt approach were used to calculate the SFE. EDS analysis was carried out to check the surface composition. E. coli bacterial strain was used to study the early colonization responses using FESEM and optical microscope. Results indicate that the formed textures are uniform with good quality and as per the design of experiment. Area surface roughness values of the textured surface have been increased from UTS. Besides, no tool wear debris has been found on textured surfaces. SFE and adhesion strength of water and diiodomethane increase due to surface texturing and initial colonization of bacteria on textured surfaces is in the form of E. coli cellular chains has been observed. The current study offers insights into the surface free energy, adhesion strength of water and diiodomethane, and bacterial attachment during the early stage of colonization. [ABSTRACT FROM AUTHOR]

Obesity and diabetes are established comorbidities for COVID-19. Adipose tissue demonstrates high expression of ACE2 which SARS- CoV-2 exploits to enter host cells. This makes adipose tissue a reservoir for SARS-CoV-2 viruses and thus increases the integral viral load. Acute viral infection results in ACE2 downregulation. This relative deficiency can lead to disturbances in other systems controlled by ACE2, including the renin-angiotensin system. This will be further increased in the case of pre-conditions with already compromised functioning of these systems, such as in patients with obesity and diabetes. Here, we propose that interactions of virally-induced ACE2 deficiency with obesity and/or diabetes leads to a synergistic further impairment of endothelial and gut barrier function. The appearance of bacteria and/or their products in the lungs of obese and diabetic patients promotes interactions between viral and bacterial pathogens, resulting in a more severe lung injury in COVID-19.

Graphical abstract Highlights • "Specific" bacteria in chicken manure transformed protein and carbohydrate. • "Universal" bacteria in bovine manure transformed both of protein and carbohydrate. • More than 79% of the variance of protein and carbohydrate were transformed by bacteria. Abstract The aim of this study was to assess the roles of bacteria in degrading protein and carbohydrate during chicken and bovine manures composting. The results showed that protein and carbohydrate degraded greatly, especially during the thermophilic phase of composting. This was mainly caused by the abundant bacteria communities that related with protein and carbohydrate transformation in the thermophilic phase, which identified by the network analysis. Besides, the microbial degradation of nutrient substances performed specificity and universality. "Specificity" and "Universality" meant protein and carbohydrate degraded by certain bacteria and diverse groups of bacteria, respectively. "Specific" bacteria transformed protein and carbohydrate during chicken manure composting, whereas the transformation characteristic of bacteria to protein and carbohydrate in bovine manure was "universality". Structural equation models also verified these results, and they showed that more than 79% of protein and carbohydrate changes were transformed by bacteria. [ABSTRACT FROM AUTHOR]

Addition of salt or salt-containing water to food is one of the oldest and most effective preservation methods in history; indeed, salt-cured foods are generally recognized as microbiologically safe due to their high salinity. However, a number of microbiological risks remain. The microbiological hazards and risks associated with salt-cured foods must be addressed more in-depth as they are likely to be underestimated by previous studies. This review examined a number of scientific reports and articles about the microbiological safety of salt-cured foods, which included salted, brined, pickled, and/or marinated vegetables, meat, and seafood. The following subjects are covered in order: (1) clinical cases and outbreaks attributed to salt-cured foods; (2) the prevalence of foodborne pathogens in such foods; (3) the molecular, physiological, and virulent responses of the pathogens to the presence of NaCl in both laboratory media and food matrices; (4) the survival and fate of microorganisms in salt-cured foods (in the presence/absence of additional processes); and (5) the interaction between NaCl and other stressors in food processes (e.g., acidification, antimicrobials, drying, and heating). The review provides a comprehensive overview of potentially hazardous pathogens associated with salt-cured foods and suggests further research into effective intervention techniques that will reduce their levels in the food chain. [ABSTRACT FROM AUTHOR]

Insects have evolved an effective immune system to respond to various challenges. In this study, a novel immune-related gene, called BmHDD1 , was first charactered in silkworm, Bombyx mori . BmHDD1 contained an ORF of 837 bp and encoding a deduced protein of 278 amino acids. BmHDD1 was specifically expressed in hemocytes, and highly expressed at the molting and metamorphosis stages under normal physiological conditions. Our results suggested that BmHDD1 was mainly generated by hemocytes and secreted into hemolymph. Our results also showed that the expression level of BmHDD1 was significantly increased after 20E injection, which indicated that BmHDD1 might be regulated by ecdysone. More importantly, BmHDD1 was dramatically induced after injected with different types of PAMPs or bacteria, either in hemocytes or fat body. Those results suggested that BmHDD1 plays a role in developing and immunity system in silkworm, Bombyx mori . [ABSTRACT FROM AUTHOR]

Terrestrial chromophoric dissolved organic matter (CDOM) could subsidize lake food webs. Trophic state and altitude have a pronounced influence on the CDOM concentration and composition of a lake. The impact of future changes in solar radiation on high-altitude lakes is particularly alarming because these aquatic ecosystems experience the most pronounced radiation variation worldwide. Photodegradation experiments were conducted on terrestrial CDOM samples from oligotrophic alpine Lake Tiancai and low-altitude eutrophic Lake Xiaohu to investigate the response of bacterial growth to photodegraded CDOM. During the photo-irradiation process, the fluorescent CDOM intensity evidently decreased in an inflowing stream of Lake Tiancai, with the predominance of humic-like fluorescence. By contrast, minimal changes were observed in the riverine CDOM of Lake Xiaohu, with the predominance of protein-like fluorescence. The kinetic constants of photodegradation indicated that the degradation rate of terrestrial (soil) humic acid in Lake Tiancai was significantly higher than that in Lake Xiaohu ( p < 0.001). Soil humic and fulvic acids irradiated in the simulated experiment were applied to incubated bacteria. The specific growth rate of bacteria incubated with soil humic substances was significantly higher in Lake Tiancai than in Lake Xiaohu ( p < 0.05). Furthermore, the utilizing rate of dissolved oxygen (DO) confirmed that the DO consumption by bacteria incubated with terrestrial CDOM in Lake Tiancai was significantly greater than that in Lake Xiaohu ( p < 0.05). In summary, the exposure of terrestrial CDOM to light significantly enhances its availability to heterotrophic bacteria in Lake Tiancai, an oligotrophic alpine lake, which is of importance in understanding bacterial growth in response to photodegraded terrestrial CDOM for different types of lakes. [ABSTRACT FROM AUTHOR]

Rapid microbiological methods to assess cell physiological properties of microorganisms are gaining interest in the elucidation of the effect of antimicrobial agents or physical inactivation. Fluorescent probes combined with flow cytometry or microplate assays provide information about cellular targets of chemical or physical stressors and help to clarify the underlying mode of action. In this work we exemplarily monitored the bacterial response of Listeria innocua , Staphylococcus aureus , Salmonella enterica and Escherichia coli to a mild thermal treatment by applying various methods to illustrate bacterial vital functions like the redox activity, membrane potential, esterase activity, efflux activity, glucose uptake, membrane integrity and plate counts. It was observed that some cellular properties are affected earlier than others. Respiration, glucose-uptake and pump activity were the most sensitive parameters, followed by the loss of membrane potential and membrane integrity. Unspecific esterase was found to be relatively resistant to mild heat exposure. This study shows that such a multi-method approach is a suitable tool to monitor the impact of inactivation treatments on bacteria, providing information about the mode of action, the heterogeneity of populations, species-specific differences to stressors and valuable insight in vital functions beyond pure culturability. [ABSTRACT FROM AUTHOR]

Abstract: Quinolones are widely used broad-spectrum antibacterials with incomplete elucidated mechanism of action. Here, molecular basis for the antibacterial action of quinolones, from target to network, is fully discussed and updated. Quinolones trap DNA gyrase or topoisomerase IV to form reversible drug-enzyme-DNA cleavage complexes, resulting in bacteriostasis. Cell death arises from chromosome fragmentation in protein synthesis-dependent or -independent pathways according to distinguished quinolone structures. In the former pathway, irreversible oxidative DNA damage caused by reactive oxygen species kills bacteria eventually. Toxin–antitoxin mazEF is triggered as an additional lethal action. Bacteria survive and develop resistance by SOS and other stress responses. Enlarged knowledges of quinolone actions and bacterial response will provide new targets for drug design and approaches to prevent bacterial resistance. [Copyright &y& Elsevier]

Abstract: This study investigates the role that surface functionalisation of silicone elastomer (SE) by atmospheric pressure plasma induced graft immobilisation of poly(ethylene glycol) methyl ether methacrylate (PEGMA) plays in the attendant biological response. SE is used in modern ophthalmic medical devices and samples of the material were initially plasma treated using a dielectric barrier discharge reactor (DBD) to introduce reactive oxygen functionalities, prior to in situ grafting of two molecular weights of PEGMA (MW 1000Da: PEGMA1000, MW 2000Da: PEGMA2000). The variously processed surfaces were characterised by water contact angle analysis, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry and atomic force microscopy. Lens epithelial cells were then cultured on the PEGMA grafted SE surfaces. It was found that cells on the pristine surface were not well spread and had shrunken morphology. On the DBD pre-treated surfaces, the cells were well spread. On the PEGMA1000 surface, the cells displayed evidence of shrinkage and were on the verge of detaching. Remarkably, on the PEGMA2000 surface, no cell adhesion was detection. Bacterial adhesion to the surfaces was studied using Staphylococcus aureus NTC8325. There was no difference in the number of bacteria adhering to any of the surfaces studied. [Copyright &y& Elsevier]

The article discusses a study on the effectiveness of dexamethasone in varying doses as an anti-inflammatory therapy during early sepsis in mice. The study procedure included the administration of dexamethasone in mice, cecal ligation and puncture, and the administration of phosphate-buffered saline. The researchers concluded that the success of anti-inflammatory therapies in a septic setting is associated to treatment balance.

Problem Methods for monocyte purification are common but few work with umbilical cord monocytes that do not activate the cell for subsequent culture analysis. Methods of study The collection procedure avoids use of needles and procedures that variably activate blood clotting and uses a purification procedure that involves diluted Ficoll, autologous serum to remove platelets and 42% and 51% Percoll step gradients for the final purification. The resulting monocytes were stimulated with bacterial lipopolysaccharide and formalin-treated bacteria Escherichia coli and group B streptococci (GBS) to secrete TNF-α and IL-1β, measured by ELISA. Results The purification procedure results in non-active but stimulation-competent monocytes with high yields (2.3–9 × 107 cells) and purity (from 70% to 98%). Conclusion We describe a procedure that is easy, uses common reagents and provides a uniformly high yield and purity of non-activated fetal monocytes for studies of innate defense responses. [ABSTRACT FROM AUTHOR]

Abstract: Antibacterial responses have been studied in Atlantic salmon following an acute intra peritoneal injection of a genetically attenuated (aroA−) strain of Aeromonas salmonicida known to elicit protective immunity. Three tissues were studied for transcriptional changes, the liver, head kidney and the gill. RNA was collected from fish 6, 12, 24 and 48h following infection or at the same time points from fish injected with PBS as non-infected control. PCR-select cDNA subtraction libraries were constructed from pooled 24 and 48h post infection RNA to identify up-regulated mRNAs. One thousand four hundred and eighty six cDNA clones were sequenced from enriched cDNA libraries, of which 71% had significant homologies to known functional proteins. Many of these clones have previously been uncharacterised in Atlantic salmon. A salmonid cDNA microarray was used to further analyse the gene expression profile as the library construction in itself does not answer the dynamics of the response. The greatest increase in expression identified in the array analysis was a liver antibacterial peptide, hepcidin that was increased 11-fold following the challenge. A panel of clones were chosen for semiquantitative reverse transcriptase PCR from all time points sampled. These results indicated there were both temporal differences and tissue differences in the transcriptional response to bacterial exposure, potentially of relevance to the establishment of protection. [Copyright &y& Elsevier]

To determine the bactericidal mechanism of electrolyzed water and mild heat against Escherichia coli O157:H7, we performed ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-qTOF-MS/MS) coupled with multivariate analysis to profile the intracellular metabolites of E. coli O157:H7 in response to electrolyzed water (EW) and mild heat treatment. The results indicated that EW (4 mg/L free available chlorine) combined with heat treatment at 50 °C resulted in 2.31 log CFU/mL reduction of E. coli O157:H7 and the reactive oxygen species fluorescence intensity of EW at 50 °C was ten times higher than that of the control group. Data demonstrated that treatment with EW and heat caused significant perturbation of metabolic pathways that were functionally related with amino acid metabolism, nucleotides synthesis, and lipid biosynthesis. EW at 50 °C resulted in major alterations to pathways involved in acyl carrier protein metabolism, anhydromuropeptides recycling, biosynthesis of CDP-diacylglycerol, trehalose and lipid IVa. Transcriptome analysis revealed that heat and EW affected the transcription levels of some genes in opposite ways. The expression of rpoS , oxyR , soxR , gadA , gadB , sucA , and sucB in the 50 °C group was downregulated, but upregulated in EW exposed cells. The expression of most genes was reduced in response to the combined treatment, with 0.024- and 0.286-fold downregulation of udk (encoding uridine kinase) and gadA (encoding glutamate decarboxylase alpha), respectively, being observed in cells treated with EW at 50 °C. These results provided further evidence of the metabolomic and transcriptomic response of E. coli O157:H7 to oxidation and heat stress. • Electrolyzed water acted synergistically with heat against E. coli O157:H7. • Monitoring cellular metabolic profile revealed bacteria physicochemical state. • EW exposure altered amino acid synthesis and nucleic acid synthesis. • EW and mild heat had distinctively different effects on metabolic flux. [ABSTRACT FROM AUTHOR]

• External EMBR was set up with superhydrophobic/organophilic electrospun membrane. • External EMBR achieved the salt rejection, phenol permeation and biodegradation. • Phenol and ammonium were simultaneously removed in external EMBR for detoxication. • Microbial community, gene enumeration and EPS release varied with phenol conc. Phenol-laden saline wastewaters can adversely affect water, groundwater, soil, organisms and ecosystems. Given that frequently-used biodegradation process is generally inhibited by salinity, this work aims to solve the problem through a novel configuration of external extractive membrane bioreactor (EMBR) for the objective of simultaneous phenol permeation, salt rejection and biodegradation. Contact angles of 160.9 ± 2.2° (water) and 0.0° (phenol) were observed on the electrospun polydimethylsiloxane/polymethyl methacrylate (PDMS/PMMA) membrane, suggesting this superhydrophobic/superorganophilic membrane was suitable for separating phenol from water-soluble salt. Phenol ranging from 14.1 ± 2.7 to 290.7 ± 10.4 mg/L (stages 1 to 8) was continuously permeated and completely biodegraded in external EMBR under a hydraulic retention time (HRT) of 24 h, which corresponded with detoxification performance improving from 6.3% to 70.5%. After phenol exposure of 8 stages, Proteobacteria and Saccharibacteria became the main phyla for microorganisms. Enumeration of functional genes (phe , amoA , narG , nirS) confirmed that phenol was mainly consumed by denitrifiers and other heterotrophs as the sole carbon and energy source via oxidation and ring cleavage. As bacterial responses, these genes' proliferation was promoted under low phenol concentrations but inhibited under high phenol concentrations. Meanwhile, results of extracellular polymeric substances revealed that protein was the key substance in toxicity resistance, phenol adsorption and transfer. [ABSTRACT FROM AUTHOR]

Obesity and diabetes are established comorbidities for COVID-19. Adipose tissue demonstrates high expression of ACE2 which SARS- CoV-2 exploits to enter host cells. This makes adipose tissue a reservoir for SARS-CoV-2 viruses and thus increases the integral viral load. Acute viral infection results in ACE2 downregulation. This relative deficiency can lead to disturbances in other systems controlled by ACE2, including the renin-angiotensin system. This will be further increased in the case of pre-conditions with already compromised functioning of these systems, such as in patients with obesity and diabetes. Here, we propose that interactions of virally-induced ACE2 deficiency with obesity and/or diabetes leads to a synergistic further impairment of endothelial and gut barrier function. The appearance of bacteria and/or their products in the lungs of obese and diabetic patients promotes interactions between viral and bacterial pathogens, resulting in a more severe lung injury in COVID-19., Competing Interests: IK ILK is the managing partner of Wellcomet GmbH. Wellcomet GmbH provided support in the form of salaries for ILK, but did not have any additional role in decision to publish or preparation of the manuscript. The commercial affiliation of ILK with Wellcomet GmbH does not alter the adherence to all journal policies on sharing data and materials. MS, PS No competing interests declared, (© 2020, Kruglikov et al.)

Addition of salt or salt-containing water to food is one of the oldest and most effective preservation methods in history; indeed, salt-cured foods are generally recognized as microbiologically safe due to their high salinity. However, a number of microbiological risks remain. The microbiological hazards and risks associated with salt-cured foods must be addressed more in-depth as they are likely to be underestimated by previous studies. This review examined a number of scientific reports and articles about the microbiological safety of salt-cured foods, which included salted, brined, pickled, and/or marinated vegetables, meat, and seafood. The following subjects are covered in order: (1) clinical cases and outbreaks attributed to salt-cured foods; (2) the prevalence of foodborne pathogens in such foods; (3) the molecular, physiological, and virulent responses of the pathogens to the presence of NaCl in both laboratory media and food matrices; (4) the survival and fate of microorganisms in salt-cured foods (in the presence/absence of additional processes); and (5) the interaction between NaCl and other stressors in food processes (e.g., acidification, antimicrobials, drying, and heating). The review provides a comprehensive overview of potentially hazardous pathogens associated with salt-cured foods and suggests further research into effective intervention techniques that will reduce their levels in the food chain., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The UV dose-response behavior of laboratory cultures of waterborne bacteria were examined for UV doses ranging from ca. 0 -100 mW.s/cm2 using a collimated-beam reactor. Specific physiological responses measured in these tests included viability (abilityto reproduce) and respiration (oxygen uptake rate). The results of these exposures indicated that resistance to UV-imposed loss of viability in E. coli cultures can be partially attributed to agglomeration during the irradiation process. From these results, it is conjecturedthat a bacterial population may be comprised of two sub-populations:one with low resistance (discrete or paired cells) and a second withhigh resistance (bacterial aggregates). A small fraction of the high-resistance portion of the population appears to be essentially unaffected by UV irradiation, thereby causing a discontinuity in the measured dose-response behavior. Moreover, the dose-response behavior of the highly resistant fraction is variable and difficult to describe quantitatively. The basis of these statements and most information in the literature is microbial viability as quantified by the membrane filtration assay. In contrast to these findings, the results of analyses for bacterial activity (respiration) suggest that comparatively little change in the population can be found to result from UV irradiation. This suggests that UV radiation accomplishes inactivation of the bacteria, but does not 'kill' the bacterial cells per se, thereby highlighting the importance of considering bacterial repair processes inthe design of UV disinfection systems. [ABSTRACT FROM AUTHOR]