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Ag@ceramic composite papermaking pigment was prepared by coating silver onto red ceramic powder using the electroless plating method. SEM and XRD showed that the ceramic pigments have a porous crystalline structure and that silver particles had been successfully loaded onto the surface and into the pores of the Ag@ceramic. Untreated ceramic pigment and Ag@ceramic pigment were incorporated into paper sheets by coating, filling and filling‐coating. Using spinach as an example, the ability of the different papers to preserve food was then evaluated. Four indicators were used to assess the preservative effect of the papers: inhibition of growth of Staphylococcus aureus and Escherichia coli, weight loss of the spinach and retention of vitamin C and chlorophyll in the spinach. Although the ceramic preservative paper has no antibacterial properties, it reduced weight loss from the spinach and increased retention of vitamin C and chlorophyll. The antibacterial preservative papers inhibited the growth of E. coli and S. aureus by >99%, and because of their additional antibacterial activity, these papers preserved the spinach more effectively. The experimental results showed that the antibacterial food‐preservative paper incorporating ceramic pigments had great potential in food packing applications. [ABSTRACT FROM AUTHOR]

Habitat spatial structure has a profound influence on bacterial life, yet there currently are no low‐cost equipment‐free laboratory techniques to reproduce the intricate structure of natural bacterial habitats. Here, we demonstrate the use of paper scaffolds to create landscapes spatially structured at the scales relevant to bacterial ecology. In paper scaffolds, planktonic bacteria migrate through liquid‐filled pores, while the paper's cellulose fibres serve as anchor points for sessile colonies (biofilms). Using this novel approach, we explore bacterial colonisation dynamics in different landscape topographies and characterise the community composition of Escherichia coli strains undergoing centimetre‐scale range expansions in habitats structured at the micrometre scale. The bacteria‐in‐paper platform enables quantitative assessment of bacterial community dynamics in complex environments using everyday materials. [ABSTRACT FROM AUTHOR]

The capacity of Ag nanoparticles to destroy various micro‐organisms makes it one of the most powerful antimicrobial agents, an attractive feature against antibiotic resistant bacteria. Here, a simple method to develop coating of colloidal silver on paper using a biological method is presented. The coated paper was studied by scanning electron microscopy, X‐ray diffraction technique and atomic absorption spectroscopy. The antibacterial activity of the coated paper against Escherichia coli and Staphylococcus aureus was measured by agar diffusion method. This study shows the potential use of the coated paper as a food antimicrobial packing material for longer shelf life. [ABSTRACT FROM AUTHOR]

The authors report Myxobacteria virescens (M. virescens) mediated synthesis of silver nanoparticles (AgNPs) and its efficacy against Staphylococcus aureus (ATCC‐33591), Salmonella typhi (ATCC‐51812), Escherichia coli (E. coli) (ATCC‐14948), Klebsiella pneumoniae (MTCC‐4030) and Pseudomonas aeruginosa (MTCC‐4673). The organism exhibiting resistance to various antibiotics showed remarkable sensitivity, when used in combination of antibiotics and AgNPs. Antimicrobial property of AgNPs is playing a significant role in medicine and food storage. In this study, they have used M. virescens for the synthesis of AgNPs, which were characterised by using UV‐Vis spectrophotometer, nano‐particles tracking and analysis, zeta potential, Fourier transform infrared spectroscopy, X‐ray diffraction and transmission electron microscopy. Synthesised AgNPs were impregnated into paper by three different methods, i.e. glass rod method (without binder), glass rod method (with binder) and direct synthesis of AgNPs on paper. Nanoparticles synthesis on paper showed the significant antimicrobial activity against Staphylococcus aureus (ATCC‐33591), Salmonella typhi (ATCC‐51812), E. coli (ATCC‐14948), Klebsiella pneumoniae (MTCC‐4030) and Pseudomonas aeruginosa (MTCC‐4673). Paper impregnated with AgNPs was used for wrapping of fruits (apples) which increases their shelf life up to 15 days. This study demonstrates a new method for wrapping of fruits, which increases the shelf life of apples. [ABSTRACT FROM AUTHOR]

Cell-free protein synthesis (CFPS) is an established method for rapid recombinant protein production. Advantages like short synthesis times and an open reaction environment make CFPS a desirable platform for new and difficult-to-express products. Most recently, interest has grown in using the technology to make larger amounts of material. This has been driven through a variety of reasons from making site specific antibody drug conjugates, to emergency response, to the safe manufacture of toxic biological products. We therefore need robust methods to determine the appropriate reaction conditions for product expression in CFPS. Here we propose a process development strategy for Escherichia coli lysate-based CFPS reactions that can be completed in as little as 48 hr. We observed the most dramatic increases in titer were due to the E. coli strain for the cell extract. Therefore, we recommend identifying a high-producing cell extract for the product of interest as a first step. Next, we manipulated the plasmid concentration, amount of extract, temperature, concentrated reaction mix pH levels, and length of reaction. The influence of these process parameters on titer was evaluated through multivariate data analysis. The process parameters with the highest impact on titer were subsequently included in a design of experiments to determine the conditions that increased titer the most in the design space. This proposed process development strategy resulted in superfolder green fluorescent protein titers of 0.686 g/L, a 38% improvement on the standard operating conditions, and hepatitis B core antigen titers of 0.386 g/L, a 190% improvement., (© 2020 The Authors. Biotechnology Progress published by Wiley Periodicals LLC on behalf of American Institute of Chemical Engineers.)

We developed a curriculum for an upper‐level molecular biology course‐based undergraduate research laboratory class funded by a National Science Foundation CAREER grant that focuses on identifying new small proteins in the bacterium, Escherichia coli. Our CURE class has been continually offered each semester for the last 10 years, with multiple instructors collaboratively developing and implementing their own pedagogical approach while maintaining the same overall scientific goal and experimental strategy. In this paper, we delineate the experimental strategy for our molecular biology CURE laboratory class, describe a range of pedagogical approaches implemented by multiple instructors, and provide recommendations for teaching the class. The purpose of our paper is to share our experiences both in developing and teaching a molecular biology CURE laboratory class based on small protein identification and in creating a curriculum and support system that allows traditional, non‐traditional, and under‐represented students to participate in authentic research projects. [ABSTRACT FROM AUTHOR]

Escherichia coli serves as a proxy indicator of fecal contamination in aquatic ecosystems. However, its identification using traditional culturing methods can take up to 24 h. The application of DNA markers, such as conserved signature proteins (CSPs) genes (unique to all species/strains of a specific taxon), can form the foundation for novel polymerase chain reaction (PCR) tests that unambiguously identify and detect targeted bacterial taxa of interest. This paper reports the identification of three new highly-conserved CSPs (genes), namely YahL, YdjO, and YjfZ, which are exclusive to E. coli/Shigella. Using PCR primers based on highly conserved regions within these CSPs, we have developed quantitative PCR (qPCR) assays for the evaluation of E. coli/Shigella species in water ecosystems. Both in-silico and experimental PCR testing confirmed the absence of sequence match when tested against other bacteria, thereby confirming 100% specificity of the tested CSPs for E. coli/Shigella. The qPCR assays for each of the three CSPs provided reliable quantification for all tested enterohaemorrhagic and environmental E. coli strains, a requirement for water testing. For recreational water samples, CSP-based quantification showed a high correlation (r > 7, p < 0.01) with conventional viable E. coli enumeration. This indicates that novel CSP-based qPCR assays for E. coli can serve as robust tools for monitoring water ecosystems and other critical areas, including food monitoring., (© 2024 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

The COVID‐19 outbreak has disrupted undergraduate students' experiments since their access to the laboratory is limited. To address this problem, the bacteria and detergent residues on undergraduate students' dinner plates were investigated by the students in the dormitories. Five different types of dinner plates from 50 students were collected, which were cleaned with detergent and water in the same way and naturally dried. Then, Escherichia coli (E. coli) test papers and sodium dodecyl sulfonate test kits were used to understand the bacteria and detergent residuals. Commonly available equipment such as a yogurt maker was used for bacterial culture; detergent analyses were performed using centrifugation tubes. Effective sterilization methods and safety protection were achieved by dormitory available methods. According to the investigated results, the students found the differences in bacteria and detergent residuals between different dinner plates and made suitable choices for the future. [ABSTRACT FROM AUTHOR]

In our own study, hemolytic I E. coli i were isolated more frequently from patients with IBD, 7 of 15, compared with healthy controls, 1 of 9; this difference did, however, not reach statistical significance (p = 0.18), Paper V. The clonal nature of I E. coli i isolated from IBD patients contradicts the possible assumption that IBD through an impaired immune system allows an overgrowth of I E. coli i at random. This indicates that a patient with IBD with a concomitant I Salmonella i , I Campylobacter i or I C. difficile i infection probably has a higher risk of a positive stool sample simply because of more frequent submission of stool samples from IBD patients compared to patients with acute gastroenteritis alone [16]. Increased levels of antibodies towards I E. coli i antigens in IBD patients, Paper VII, supports a more direct interaction of I E. coli i with the immune system in IBD patients, even though IBD medications will also influence the serologic response, Paper VIII. Increased levels of antibodies towards I E. coli i antigens in IBD patients further support a more direct interaction of I E. coli i with the immune system in IBD patients, Paper VII, even though IBD medications will also influence the serologic response, Paper VIII. Recently, through metagenomics in a pediatric population comparing IBD patients with their healthy siblings, a strong correlation to IBD has been found with the abundance of bacterial virulence genes, enriched specifically in the UC microbiome with I E. coli i abundance, suggesting that I E. coli i is a central driver in UC pathogenesis [113]. [Extracted from the article]

Zinc protoporphyrin IX (ZnPPIX) has been considered as a promising red colorant for food industries as well as an anticancer drug. However, bio‐based production of ZnPPIX from a renewable carbon source has not been reported yet. In this study, a fermentation process of the metabolically engineered Escherichia coli HAEM7 strain was optimized for the high‐level production of ZnPPIX. To repurpose the HAEM7 strain that was originally developed for the production of heme into a producer of ZnPPIX, the concentrations of iron and zinc in the culture medium were rebalanced. Next, the concentration of zinc in the feeding solution was optimized to improve ZnPPIX production. Moreover, the pH control strategy, induction point, and the strategy of increasing the cell density, which were optimized in the accompanying paper for the high‐level production of heme, were applied together. In the optimized fermentation process, the HAEM7 strain produced 2.2 g/L ZnPPIX with a productivity of 39.9 mg/L/h. The fermentation process and strategies reported here will expedite establishing industry‐level production of ZnPPIX. [ABSTRACT FROM AUTHOR]

ABSTRACT The synthesis of four distinct protein‐based metal nanocomposites has been fabricated by employing egg albumin and zinc metal through a simple, straightforward two‐step method. The Fourier transform infrared (FTIR), X‐ray diffraction (XRD), and scanning electron microscopy (SEM) analyses confirmed the successful incorporation of zinc nanoparticles into the protein matrix and revealed an irregular microporous structure with average crystallite sizes of less than 100 nm. Thermal stability was assessed via thermogravimetric (TG) and derivative thermal gravimetry (DTG) analysis, revealing a notable increase in thermal stability in a high‐temperature range (300°C°C–700°C), suggesting remarkable stability at elevated temperatures. Antimicrobial efficacy against both gram‐positive (B. cereus and Lactobacillus spp.) and gram‐negative bacteria (E. coli and K. pneumoniae) was evaluated using paper disk diffusion, pour plate, and minimum inhibitory concentration (MIC) methods. All samples exhibited antibacterial efficacy, with zone of inhibition (ZOI) diameters ranging from 12 to 35 mm, and demonstrated a bactericidal effect by eliminating 93 to 98% of bacteria within 8 to 20 h at their MICs. Notably, protein–ZnO–PANI exhibited potent antimicrobial activity against all four bacterial strains and among all the samples, demonstrated higher antimicrobial activity than the unpolymerized nanocomposites. The disk diffusion study confirmed that a concentration of 25 μg/mL of protein–ZnO–PANI resulted in ZOI measurements of 25 mm and 35 mm, whereas MIC values of 300 μg/mL and 200 μg/mL were observed against Bacillus cereus and E. coli, respectively, and killed 95% of B. cereus and 98% of E. coli within 24 h. Based on the obtained results, a plausible mechanism was also proposed. [ABSTRACT FROM AUTHOR]

With the increase of drug‐resistant bacteria and the limitations of traditional antibacterial methods, photocatalytic inhibition has received widespread attention as a novel antibacterial method. In this paper, poly(1‐vinyl‐3‐ethylimidazolium tetrafluoroborate) composite oxygenated carbon nitride (PBF‐OCN) were prepared by in situ free radical polymerization using 1‐vinyl‐3‐ethylimidazolium tetrafluoroborate and OCN. The results showed that the light absorption ability and electron hole separation rate of PBF‐OCN were greatly improved compared with that of OCN, and the rate constant for photocatalytic removal MB of PBF‐OCN‐1 was about 1.39 times of that OCN. The growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) could be significantly inhibited by PBF‐OCN under visible light, among which, the inhibition of PBF‐OCN‐3 was the most excellent, with the diameter of the circle of inhibition reaching 20.69 mm for E. coli, and 21.30 mm for S. aureus, and the inhibition rate against E. coli calculated by plate counting method reached 97.0%. The minimum inhibitory concentration for E. coli and S. aureus was 0.0625 mg/mL, respectively, and the possible inhibition mechanism of the samples was explored. The good synergistic antibacterial effect of PBF‐OCN is expected to be applied in water treatment, antibacterial devices, packaging materials, and other fields. [ABSTRACT FROM AUTHOR]

This document is a corrigendum to an article published in the New Phytologist journal. The authors of the original article have identified errors in their work. Specifically, the equation used for carotenoid quantification in the Materials and Methods section was incorrect, resulting in incorrect graphs. The corrected equation and graphs are provided in the corrigendum. The errors do not change the conclusions of the paper. The authors apologize for the mistakes. [Extracted from the article]

Klebsiella pneumoniae (Kp) is an infectious disease pathogen that poses a significant global health threat due to its potential to cause severe infections and its tendency to exhibit multidrug resistance. Understanding the enzymatic mechanisms of the oxygen‐insensitive nitroreductases (Kp‐NRs) from Kp is crucial for the development of effective nitrofuran drugs, such as nitrofurantoin, that can be activated as antibiotics. In this paper, three crystal structures of two Kp‐NRs (PDB entries 7tmf/7tmg and 8dor) are presented, and an analysis of their crystal structures and their flavin mononucleotide (FMN)‐binding mode is provided. The structures with PDB codes 7tmf (Kp‐NR1a), 7tmg (Kp‐NR1b) and 8dor (Kp‐NR2) were determined at resolutions of 1.97, 1.90 and 1.35 Å, respectively. The Kp‐NR1a and Kp‐NR1b structures adopt an αβ fold, in which four‐stranded antiparallel β‐sheets are surrounded by five helices. With domain swapping, the β‐sheet was expanded with a β‐strand from the other molecule of the dimer. The difference between the structures lies in the loop spanning Leu173–Ala185: in Kp‐NR1a the loop is disordered, whereas the loop adopts multiple conformations in Kp‐NR1b. The FMN interactions within Kp‐NR1/NR2 involve hydrogen‐bond and π‐stacking interactions. Kp‐NR2 contains four‐stranded antiparallel β‐sheets surrounded by eight helices with two short helices and one β‐sheet. Structural and sequence alignments show that Kp‐NR1a/b and Kp‐NR2 are homologs of the Escherichia coli oxygen‐insensitive NRs YdjA and NfnB and of Enterobacter cloacae NR, respectively. By homology inference from E. coli, Kp‐NR1a/b and Kp‐NR2 may detoxify polynitroaromatic compounds and Kp‐NR2 may activate nitrofuran drugs to cause bactericidal activity through a ping‐pong bi‐bi mechanism, respectively. [ABSTRACT FROM AUTHOR]

Using water quality indices (WQIs) is one way to monitor watercourses for water quality. Currently, there is a lack of information about their behavior in the diurnal cycle because sampling is often carried out in the morning. Also, few articles focus on assessing the urban impact on the spatial variability of WQIs in tropical first‐order streams. Such streams receive many pollutants varying in intensity according to population habits, justifying the possible diurnal variation in water quality in addition to climatic attributes. This paper aims to evaluate the fluctuations in Brazilian WQIs and their parameters (temperature, turbidity, total solids [TS], hydrogen potential, dissolved oxygen [DO], biochemical oxygen demand [BOD], total phosphorus [TP], total nitrogen [TN], and Escherichia coli) between the morning (8 AM), afternoon (2 PM), and night (7 PM) periods for an urban first‐order tropical stream. Overall, the lowest DO concentrations and highest values of TS, turbidity, BOD, TP, TN, and E. coli were obtained in the morning, possibly representing population habits: the greatest generation of pollutants occurs overnight and in the early morning because there are clandestine domestic wastewater inputs into the stream, whose hourly periodicity generates a similar periodicity in the WQI of the evaluated stream. Although there was a significant variation in WQI average values between morning (15.50 ± 1.97) and afternoon (20.83 ± 5.42) only during the dry season (p < 0.05), different results were common throughout the day in all months, and the water quality was often classified in distinct categories: very bad, bad, and regular. Our findings present another dimension to be considered when assessing urban water quality, leading to direct benefits to the management and use of urban waters. Integr Environ Assess Manag 2022;18:1260–1271. © 2021 SETAC Key Points: This paper presents the variations in the Brazilian water quality index (WQI) and its parameters between three periods of the day (8 AM, 2 PM, and 7 PM).The greatest generation of clandestine domestic effluents occurs overnight and in the early morning, whose hourly periodicity generates a similar periodicity in the WQI.Our findings present another dimension to be considered when assessing urban water quality, leading to direct benefits to the management and use of urban waters.All parameters are equally important for the Brazilian WQI since no parameter can replace other parameters (possible if they would have similar behavior at all periods). [ABSTRACT FROM AUTHOR]

The production of paper‐based food packaging materials is of vital importance as the release of microplastics into aqueous environment and food chain has aroused significant public concern. In this study, antibacterial pulp board was demonstrated by co‐spraying chitosan (CS) and ε‐polylysine (ε‐PL) on wet sheet and dried to form fibrous pulp board (ε‐PL‐CS). ε‐PL functionalization showed great antibacterial performance while its hydrophilicity limited its further application for food packaging. Interestingly, ε‐PL‐CS pulp board not only demonstrated excellent antibacterial performance (99.99% against both bacteria Staphylococcus aureus and Escherichia coli), but also maintained high hydrophobicity (ca. 135°) and water resistance due to the positive charge of ε‐PL and CS as well as penetration of CS into pulp board. In addition, CS functionalization significantly improved the mechanical strength of the pulp board by around 100% (20 MPa). More importantly, the ε‐PL‐CS pulp board could successfully prevent bacteria growth within 15 days at room temperature due to their high hydrophobicity and smooth surface, indicating the long‐term stability as packaging materials. Satisfactory strawberry storage stability of ε‐PL‐CS cardboard lunch box provided great application promise for the development of antimicrobial packaging materials. [ABSTRACT FROM AUTHOR]

The colonization of bacteria and biofilm formation on the surface of medical devices is one of the main causes of nosocomial infections. The development of antimicrobial functional materials with robust and universal properties has been a hot research topic in this field. In this paper, a novel type of polyurethane composite coating was developed by a complementary combination of polyurethane and antibacterial agents. A photocurable anionic waterborne polyurethane was first synthesized using polycarbonate diol (PCDL), isophorone diisocyanate (IPDI), 2,2-dimethylolpropionic acid (DMPA), and hydroxyethyl acrylate (HEA) as raw materials. Polyurethane composite coatings were prepared by associating cationic antibacterial agents with polyurethane molecules through electrostatic assembly, hydrophobic interactions and hydrogen bonding, and the mechanical properties, adhesion, and antibacterial properties of the polyurethane composite coatings were studied. The results showed that the polyurethane composite coatings had good mechanical properties, and the introduction of cationic antibacterial agents significantly improved the antibacterial ability of the polyurethane material. The antibacterial efficiency of polyurethane against E. coli and S. aureus reached 99% and exhibited durable antibacterial performance as well. Moreover, the polyurethane composite coatings showed excellent adhesion to a variety of substrates, demonstrating their potential application as a universal antimicrobial coating in the medical field. [ABSTRACT FROM AUTHOR]

Infections with multidrug‐resistant Gram‐negative bacteria constitute a silent pandemic threat that is increasing globally. A major technical and scientific hurdle hampering the development of efficient antibiotics against Gram‐negative species is the low permeability of their outer membrane that prevents the entry of most small molecules into the cells. This can be overcome by targeting active iron transport systems of the pathogens in a Trojan‐Horse strategy that makes use of drug‐loaded artificial siderophores. While we utilized catechols as iron‐binding motifs in previous work, this study reports the design, synthesis and characterization of siderophores with a DOTAM scaffold that was substituted with three hydroxamate arms allowing for a hexacoordination of iron. Their iron‐chelating capabilities were shown colorimetrically, and the ability of compound 1 to deliver iron into Escherichia coli in a chelation‐specific manner was proven by a growth recovery assay. A covalent siderophore‐ciprofloxacin conjugate exerted antibiotic effects against E. coli, albeit it was less potent than the free drug. The study qualifies artificial DOTAM siderophores with hydroxamate binders as scaffolds for bacterial Trojan Horses. This contribution for honoring my mentor Helmut Schwarz echoes two motifs of my work with him: Hydroxylamin, the topic of my first paper ever, and the fascinating properties of iron ions, studied in the gas phase during my Ph.D. Thesis, became a core subject of our current chemical biology research on antiinfectives. [ABSTRACT FROM AUTHOR]

Pfu DNA polymerase is a vital enzyme in PCR-related experiments. However, it is not easy to achieve high-level expression and high purity through one-step purification. This paper illustrates the method to acquire the full-length open reading frame of Pfu DNA polymerase. Without altering its amino acids, we have modified the codon usage, based on that of the enhanced green fluorescence protein (eGFP), and named it rPfu. The synthesized rPfu gene has been subcloned into the pET28a plasmid and expressed in four Escherichia coli strains without the pLysS plasmid. Three strains have expressed a high level of soluble Pfu DNA polymerase. With the aid of Ni-NTA His•Bind ® resin, we could obtain high purity (>95%) soluble recombinant protein. Compared with the commercial, proofreading DNA polymerase, rPfu's bioactivity was 12,987 U/mg; that is, 88,311 U of rPfu could be obtained from 50 mL cultured E. coli. The purified rPfu was able to amplify the length of DNA fragments at least 5.5 kb. The method of increasing soluble protein's yield using the eGFP codon usage may introduce a new possibility to the expression of other soluble recombinant proteins., (© 2022 International Union of Biochemistry and Molecular Biology, Inc.)

Since ancient times, humans have learned to use fire and other heating methods to fight against dangerous pathogens, like cooking raw food, sterilizing surgical tools, and disinfecting other pathogen transmission media. However, it remains difficult for current heating methods to achieve extremely fast and highly efficient sterilization simultaneously. Herein, an ultrafast and uniform heating‐based strategy with outstanding bactericidal performance is proposed. Ultra‐precise laser manufacturing is used to fabricate the Joule heater which can be rapidly heated to 90 °C in 5 s with less than 1 °C fluctuation in a large area by real‐time temperature feedback control. An over 98% bactericidal efficiency on S. aureus for 30 s and on E. coli for merely 5 s is shown. The heating strategy shows a 360 times faster acceleration compared to the commonly used steam sterilization from the suggested guidelines by the Centers for Disease Control and Prevention (CDC), indicating that high temperatures with short duration can effectively disinfect microorganisms. As a proof of concept, this heating strategy can be widely applied to sterilizing cash and various objects to help protect the public from bacteria in daily life. [ABSTRACT FROM AUTHOR]

A series of novel thermoplastic polyurethane elastomers with both low surface energy and antibacterial activity were synthesized in this paper. Firstly, four imidazole salt diols with different alkyl chain lengths at the N‐position of imidazolium cation ([CnIm+][Cl−]) were prepared. Then, imidazolium‐based ionic thermoplastic polyurethane elastomers (Si‐ITPUs) were formulated by incorporating polydimethylsiloxane and polytetramethylene glycol as a mixed soft segment, 1,4‐butanediol and [CnIm+][Cl−] as a chain extender, and 4,4′‐dicyclohexylmethane diisocyanate. The structure, thermal stability, mechanical properties, physical crosslinking density, and the anti‐graffiti properties of Si‐ITPUs were evaluated. The surface energy and water absorption were evaluated through static contact angle and water resistance tests, respectively. Furthermore, the antibacterial activities against both Staphylococcus.aureus and Escherichia coli were characterized by the plate colony counting method. The results demonstrated that Si‐ITPUs possessed surface energy of approximately 23 mN/m, which conferred excellent anti‐graffiti and self‐cleaning performance. Furthermore, the increase of the alkyl chain length of substitutions resulted in a decrease in the tensile strength but an increase in the elongation at break. Si‐ITPU‐C4 exhibited optimized antibacterial activities with an antibacterial rate of more than 99.9% against both S. aureus and E. coli. This novel polyurethane is anticipated to find applications in the medical device industry and food processing sector. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 (STEC) is one of the hazardous foodborne pathogens in milk. Although traditional preservation methods reduce contamination, they are time‐consuming or cause physicochemical changes. Therefore, we optimize STEC inactivation in goat's milk by thermosonication, an alternative to traditional treatments. Different times (1–35 min) and temperatures (45.9–74.1°C) were applied, using a Central Composite Rotatable Design (CCRD). Lipid oxidation was adopted as an optimization limiting factor. Mathematical models described STEC inactivation and lipid oxidation with high performance, considering the high R2adj (0.942 and 0.731), and low mean square error (0.065 and <0.0001) and lack‐of‐fit (0.133 and 0.183). Validation was verified by the accuracy (1.141 and 1.017) and bias (0.992 and 1.006) factors, and the relative error of prediction (0.910 and 1.000). Both variables affected STEC inactivation linearly, enhancing decontamination. Lipid oxidation was affected by time, increasing oxidation products formation. Optimization was achieved around 1–20 min/62–74°C, improving STEC inactivation (6.6 log CFU/ml) with minimal lipid oxidation (0.06 mg MDA/L). Therefore, thermosonication represents a promising technology facing to traditional methods, ensuring bacteriological safety and minimal alterations. Practical Applications: Despite traditional methods for milk decontamination still being considered effective, there are some reports on pasteurized milk and dairy products‐related outbreaks. High‐intensity ultrasound is an emerging non‐thermal technology recently explored as a pathogen reduction method, used individually or combined. However, due to cavitation mechanism and free radicals realizing, some oxidative alterations could occur during processing. The present research paper contributes to provide a better understanding on the combined application of ultrasound and heat (thermosonication) to inactivate Escherichia coli in caprine milk. The findings herein are promising to the industrial utilization of thermosonication to obtaining safety products with minimal oxidative changes. [ABSTRACT FROM AUTHOR]

BACKGROUND: Point‐of‐use filtration units often incorporate silver as a disinfection aid. However, system performance and robustness may be increased by considering co‐application of additional transition metal nanoparticles (NPs) to support treated water disinfection. In this paper, the use of silver (Ag), zinc (Zn) and copper (Cu) NPs as disinfectants within drinking water applications was explored. Disinfection efficiency against E. coli was investigated over 72 h in batch‐phase experiments using NP concentrations within or lower than drinking water limits. Concentration ranges of the NPs were from 0 to 200 μg L−1, reflecting typical concentration reports for Ag in similar applications. Samples were examined with respect to pH and two water types. The effect of co‐application of NPs was assessed for potential synergy using the Bliss model, which compares individual treatment performance to combined treatment results. RESULTS: Disinfection efficacy when applying NPs individually was Ag > Cu > Zn with, for instance, complete removal (≥3 log) of E. coli observed with 50 ppb Ag at 24 h, 1 log removal by Cu and no removal achieved with application of Zn. The Bliss model analysis demonstrated the co‐application of NPs resulted in synergistic behavior with the combinations. Zn‐containing combinations (Ag–Zn and Cu–Zn) were significantly more synergistic than the Ag–Cu combination. CONCLUSIONS: Low‐level (0–200 ppb) concentrations of Ag, Cu and Zn demonstrated effective bacterial control and disinfection for E. coli under various water quality scenarios. In particular, co‐application of transition metal NPs increased system robustness and synergy, demonstrating potential for disinfection with water treatment applications. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

BACKGROUND: Microfluidic devices have been increasingly used as tools to accelerate the development of new biomanufacturing methods, given their ability to test a large set of variables in a short amount of time with minimal reagent consumption. However, while being able to expedite a bioprocess design, the modular aspect of these devices has not been systematically explored, with most applications focusing on single unitary operations. This paper explores the modular design of these devices through the development of an integrated microfluidic chip. RESULTS: Two separate unitary operations were included into a single device for continuous operation: product release by chemical cell lysis and product concentration by aqueous two‐phase system. In this way, it is possible to screen multiple conditions for each operation and evaluate their combined effect on the final product, making this a great tool in the development and optimization of a process. A recombinant Escherichia coli (E. coli) strain producing green fluorescent protein (GFP) was used as model system, which allows for lysis efficiency and partition coefficient to be evaluated by fluorescence microscopy. A chemical lysis solutions was used in the lysis step, presenting lysis efficiencies of about 100%, while a polyethylene glycol (PEG)/phosphate system was screened for the separation stage, presenting partition coefficients of about 4. CONCLUSIONS: The integrated device allowed for the continuous screening of multiple combinations of operation conditions, highlighting, for example, conditions where improvements on the lysis efficiency subsequently impaired the separation, decreasing the partition of the target product, thus demonstrating the need for the evaluation of a process in its entirety. In this way, the microfluidic device delivered a rapid process screening and optimization, with very low reagent consumption, and using a simple fluorescence microscope for data collection. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

For the nontraditional aggregation‐induced emission (AIE) active polymers, the heterocyclic structure on the macromolecular backbone and side chains play a crucial role in its fluorescence generation. In this paper, we facilely prepared a series of poly(β‐lactam) derivatives (PLTM) by Staudinger polymerization. As expected, PLTMs with four‐membered heterocycles along the main‐chain shows a remarkable AIE performance with the fluorescence emission at 520 nm, while no fluorescence was observed for both β‐lactam (repeating unit) and a model polymer for PLTM. The fluorescence properties of PLTMs greatly depend on the intramolecular aggregation of β‐lactam structures, the size of the substituents, and appropriate length of CH2 spacer. In addition, PLTMs can specifically detect Fe3+ ions with a limit of detection (LOD) of 7.2 μM even in the presence of other 13 metal ions. Similar to the biological activity of β‐lactam, AIE‐active PLTMs shows a bactericidal effect on Staphylococcus aureus and Escherichia coli with the minimum inhibitory concentration of about 8 and 4 mg/mL. In brief, the preparation and versatility of PLTMs with β‐lactam structure provide useful references for designing other nontraditional AIE‐active polymers as well as for ion detection and antibacterial processes. [ABSTRACT FROM AUTHOR]

In this paper, 2‐hydroxyethyl methacrylate (HEMA) was graft copolymerized onto chitosan (CHI) at different ratios using a radical initiator. The grafted hydrogel composites were then characterized by attenuated total reflection Fourier transform ınfrared spectroscopy (ATR‐FTIR) and thermo‐gravimetric analysis (TGA). Swelling behavior of the hydrogels was investigated at different pH and different times. The antimicrobial activity of the chitosan‐graft‐HEMA (CHI‐HEMA) against gram‐negative bacteria and gram‐positive bacteria was studied by the standard agar well diffusion assay method. The CHI‐HEMA 1:1 and CHI‐HEMA 1:2 showed an obvious antimicrobial effect against six test strains. The CHI‐HEMA 1:1 and CHI‐HEMA 1:2 exhibited a highly significant increase (p < 0.01) in diameter of the inhibition zones compared with the standard antibiotics. Furthermore, CHI‐HEMA 1:1 presented the highest antimicrobial activity against all test strains with a significant difference (p < 0.01) compared with CHI‐HEMA 1:2. Meanwhile, the decreasing order of the average sensitivity to CHI‐HEMA 1:1 and CHI‐HEMA 1:2 was observed to be S. marcescens > E. coli > S. aureus subsp. aureus > S. enteritidis > E. faecalis > E. aerogenes. These results indicate potential application of CHI‐HEMA 1:1 and CHI‐HEMA 1:2 graft hydrogels as a novel and efficient antimicrobial agent in biomedical fields. [ABSTRACT FROM AUTHOR]

The traditional approach of fermentation by a free cell system has limitations of low productivity and product separation that need to be addressed for production enhancement and cost effectiveness. One of potential methods to solve the problems is cell immobilization. Microbial cell immobilization allows more efficient up-scaling by reducing the nonproductive growth phase, improving product yield and simplifying product separation. Furthermore, the emergence of nanomaterials such as carbon nanotubes, graphene, and metal-based nanomaterials with excellent functional properties provides novel supports for cell immobilization. Nanomaterials have catalytic properties that can provide specific binding site with targeted cells. However, the toxicity of nanomaterials towards cells has hampered its application as it affects the biological system of the cells, which cannot be neglected in any way. This gray area in immobilization is an important concern that needs to be addressed and understood by researchers. This review paper discusses an overview of nanomaterials used for cell immobilization with special focus on its toxicological challenges and how by understanding physicochemical properties of nanomaterials could influence the toxicity and biocompatibility of the cells., (© 2020 International Union of Biochemistry and Molecular Biology, Inc.)

The application of collagen‐based hydrogel is severely restricted due to its poor mechanical strength and functional singleness. In this paper, two‐dimensional MXene nanosheets were introduced into collagen/acrylic acid (AA) system, which was polymerized in situ to produce versatile hydrogel (GCol‐MX‐PAA). The tensile stress and compressive stress values of the resultant hydrogel at the MXene concentration of 5 mg/mL reached 211.5 kPa and 7.8 MPa, respectively, which were approximately 4.0 and 1.4 times higher than those of GCol‐PAA. The bonding strength of the hydrogel reached 30.7 kPa in the porcine skin‐adhesive model owing to the large number of free phenolic hydroxyl groups on GCol. Furthermore, GCol‐MX‐PAA could be applied to monitor large and subtle activities of human body due to the excellent electrical conductivity of MXene. Thanks to the outstanding photothermal conversion performance of MXene, the hydrogel could kill E. coli and S. aureus effectively under NIR irradiation. In addition, in vitro cytotoxicity test performed on L929 fibroblasts demonstrated the desirable biocompatibility of GCol‐MX‐PAA. The design strategy in this work gives guidance for the development of multifunctional collagen‐based hydrogel in a wide range of applications. Highlights: Versatile hydrogel constructed from GA‐modified collagen, PAA, and MXene.The composite hydrogel displays improved mechanical properties.This hydrogel possesses superior tissue adhesion and strain sensitivity.This hydrogel shows desired photothermal antibacterial property and biocompatibility. [ABSTRACT FROM AUTHOR]

This paper reports the development of a three‐layer antibacterial cartridge system for water filtration applications. Chitosan/poly(lactic acid) (CS/PLA) nanofibers with various blend ratios are produced through an electrospinning technique. Finer and more uniform nanofibers are obtained at a 70/30 CS/PLA blend ratio, which demonstrate average 86% and 84% antibacterial activity against Staphylococcus aureus (S. aureus, Gram positive) and Escherichia coli (E. coli, Gram negative) bacteria, respectively. In order to further enrich the antibacterial activity, silver nanowires (AgNWs) are synthesized by a Solvothermal method and loaded into 70/30 CS/PLA nanofibers, in varying concentrations, to fabricate a CS/PLA/AgNW composite nanofibrous membrane. The CS/PLA/AgNW nanofibrous membrane loaded with 3% AgNWs demonstrates 100% antibacterial activity against both types of bacteria. The developed novel materials also adsorb heavy metal ions. Moreover, the silver leach‐out tendency of this fibrous web is found to be just 0.003 ppm over a 36 h time frame, which is well within the acceptable limit prescribed by WHO (<0.1 ppm). This 3% CS/PLA/AgNW composite nanofibrous membrane is coated over polyester nonwoven and used as a middle‐layer in the development of a three‐layer antibacterial cartridge system, which effectively removes bacterial and heavy metal ion contaminants from pond water to an extent desired to deem it potable. [ABSTRACT FROM AUTHOR]

In this paper, new magnetic chitosan‐salicylaldehyde Schiff base (ChS@Fe2O3) was prepared and characterized by FT‐IR, DSC, XRD, VSM and SEM and utilized as an efficient sorbent for the removal of Pb(II) and Cd(II) ions from aqueous solution. Moreover, the effect of solution pH, Pb(II) and Cd(II) initial concentration, adsorbent dosage and contact time on the adsorption process was examined thoroughly and optimized. Also, the adsorbent reusability and adsorption mechanism were studied. The sorption capacity of Pb(II) and Cd(II) ions at optimum condition was found to be 135.8 and 114.8 mg/g, respectively. The adsorption efficiency of ChS@Fe2O3 remained above 88 and 72%, respectively for Pb(II) and Cd(II) ions. Finally, antibacterial activities evaluation of ChS@Fe2O3 were conducted against S. aureus, B. cereus, E. coli and P. aeruginosa bacteria strains. The results exhibited the high activity against all bacteria strains. [ABSTRACT FROM AUTHOR]

This paper proposes a cationic double‐network hydrogel, which has good electrical conductivity, antibacterial properties, antiprotein adsorption, and mechanical properties. The cationic polymer formed a conductive path in the hydrogel network, so that the gel had good conductivity. With the increase of carboxybetaine ester, the conductivity gradually increases. As a sensor, hydrogel could respond quickly to strains such as stretching and bending. In addition, the hydrogel showed excellent antibacterial properties against Escherichia coli, the antibacterial rate can reach up to 99%. After hydrolysis, the hydrogel showed stable antiprotein adsorption performance. The tensile strength of the gel could reach 1.05 MPa, and the elongation at break was 474.31%. Therefore, this gel may be used for dressing and electronic skin. And the morphology of the hydrogel was characterized by FT‐IR, X‐ray diffraction, and SEM. [ABSTRACT FROM AUTHOR]

The article focuses on a 12-year-old female with bilateral hydrosalpinx and repeated acute abdomen, despite being negative for sexually transmitted diseases. Topics discussed include the patient's clinical presentation, diagnostic findings, surgical intervention, recurrence, and the potential involvement of Escherichia coli in hydrosalpinx development in non-sexually active individuals.

Spermidine N‐acetyltransferase (SpeG) transfers an acetyl group from acetyl‐coenzyme A to an N‐terminal amino group of intracellular spermidine. This acetylation inactivates spermidine, reducing the polyamine toxicity that tends to occur under certain chemical and physical stresses. The structure of the SpeG protein from Vibrio cholerae has been characterized: while the monomer possesses a structural fold similar to those of other Gcn5‐related N‐acetyltransferase superfamily members, its dodecameric structure remains exceptional. In this paper, structural analyses of SpeG isolated from Escherichia coli are described. Like V. cholerae SpeG, E. coli SpeG forms dodecamers, as revealed by two crystal structures of the ligand‐free E. coli SpeG dodecamer determined at 1.75 and 2.9 Å resolution. Although both V. cholerae SpeG and E. coli SpeG can adopt an asymmetric open dodecameric state, solution analysis showed that the oligomeric composition of ligand‐free E. coli SpeG differs from that of ligand‐free V. cholerae SpeG. Based on these data, it is proposed that the equilibrium balance of SpeG oligomers in the absence of ligands differs from one species to another and thus might be important for SpeG function. [ABSTRACT FROM AUTHOR]

Optimal tip sonication settings, namely tip position, input power, and pulse durations, are necessary for temperature sensitive procedures like preparation of viable cell extract. In this paper, the optimum tip immersion depth (20–30% height below the liquid surface) is estimated which ensures maximum mixing thereby enhancing thermal dissipation of local cavitation hotspots. A finite element (FE) heat transfer model is presented, validated experimentally with (R2 > 97%) and used to observe the effect of temperature rise on cell extract performance of Escherichia coli BL21 DE3 star strain and estimate the temperature threshold. Relative yields in the top 10% are observed for solution temperatures maintained below 32°C; this reduces below 50% relative yield at temperatures above 47°C. A generalized workflow for direct simulation using the CONSOL code as well as master plots for estimation of sonication parameters (power input and pulse settings) is also presented. [ABSTRACT FROM AUTHOR]

Regression techniques are often used to predict responses across landscapes or under scenarios describing changes in climate, management, or land cover. The ability of random forests (RFs) and multivariate adaptive regression splines (MARS) to predict flow variability, low flow, Escherichia coli, and a macroinvertebrate community index was compared. Cross validation was applied to test predictive performance across an induced spectrum of interpolation to extrapolation by splitting each data set into two geographical, environmental, and random groups. RF and MARS both represent nonlinear and interacting patterns but showed contrasting ability to interpolate and extrapolate. RF always performed better than MARS when interpolating within environmental space or extrapolating in geographical space. RF models for all four responses were transferable in geographic space but not to environmental conditions outside the training data. Neither technique was successful when extrapolating across environmental gradients, although RF out‐performed MARS, despite RF predictions being constrained by the training data. New methods to quantify interpolation versus extrapolation for predictions are demonstrated. Degree of extrapolation is calculated by transforming both the training data and new predictors in response turnover space. A decline in cross‐validation performance was related to an increase in degree of extrapolation regardless of whether extrapolating in geographical or environmental space. Degree of extrapolation is valuable. It identifies those predictions that are more reliable because they represent interpolation versus those that are more uncertain that represent extrapolation. For example, high degree of extrapolation under climate or land cover change indicates increased risk of producing misleading predictions from both RF and MARS. Plain Language Summary: Regression models are used across the environmental sciences to find patterns between a response and its potential predictors. These patterns can be used to predict a response across broad areas or under new environmental conditions. This paper compares performance of two flexible regression techniques when predicting across a deliberately induced spectrum of interpolation to extrapolation. Various data sets were divided into two geographical, environmental and random groups. Models were trained on one half of the data and tested on the other. The two methods incorporate nonlinear and interacting relationships but suffer from unquantified uncertainty when extrapolating. Random forests always performed better than multivariate adaptive regression splines when interpolating within environmental space, and when extrapolating in geographical space. Random forests models were transferable in geographic space but not to environmental conditions outside the training data. Neither technique was successful when extrapolating across environmental gradients. The paper also describes and tests a new method to calculate degree of extrapolation: a value quantifying interpolation versus extrapolation for each prediction from either regression technique. The method can be used to indicate risk of spurious predictions when predicting at new locations (e.g., nationally) or under new environmental conditions (e.g., climatic change). Key Points: Random forests predict flow variability, low flow, Escherichia coli, and a macroinvertebrate index across a river network better than MARSA new method for determining degree of extrapolation for predictions from random forests and MARS is presentedThe method can be used to indicate risk of spurious predictions when predicting under new environmental conditions [ABSTRACT FROM AUTHOR]

An electroporation that formed the pores on cell membrane after application of high electric field pulses has been used the transformation and the sterilization of cell. In this paper, we reported the extraction method of nucleic acid in Escherichia coli and Saccharomyces cerevisiae using high electric field pulse application. The sample was 1.0 × 10–3 mol/L NaCl aqueous solution contained E. coli and S. cerevisiae. High voltage pulse is applied to the sample at room temperature. These results were shown as the following: (1) When a pulsed electric field of 4 ∼ 13 kV/mm is applied to E. coli and S. cerevisiae, the estimated amount of nucleic acid increases with the increases of strength of applied pulsed electric field. (2) In the case of E. coli, the 2–3 kbp band was confirmed at an electric field of 5 kV/mm or more, and the 10 kbp band was confirmed at an electric field of 8 kV/mm or more. (3) In the case of S. cerevisiae, the 2–3 kbp band was confirmed at an electric field of 9 kV/mm or more. the 10 kbp band could not be confirmed at 13 kV/mm or less. [ABSTRACT FROM AUTHOR]

Ebselen, an organo‐selenium compound with well‐characterized toxicology and pharmacology, recently exhibited potent antibacterial activity against glutathione (GSH)‐negative bacteria by disrupting redox homeostasis. In this paper, we show that ebselen and silver ion in combination exert strong bactericidal activity against multidrug‐resistant (MDR) uropathogenic Escherichia coli (UPEC) BC1, a model MDR GSH‐positive bacterium. The mechanisms were found to involve consumption of total intracellular GSH and inhibition of thioredoxin reductase activity, which was highly related to reactive oxygen species up‐regulation. Furthermore, the therapeutic efficacy of ebselen and silver ion against UPEC‐induced cystitis was assessed in a mouse model. Treatment with ebselen and silver ion significantly reduced bacterial loads, down‐regulated the expression levels of tumour necrosis factor‐α (TNF‐α) and interferon‐γ (IFN‐γ) on‐site and decreased white/red blood cell counts in mild cystitis model mice, which demonstrated the anti‐inflammatory property of these agents. In addition, ebselen and silver ion also exhibited significantly high protective ability (100%) against acute cystitis infections. These results together may lay the foundation for further analysis and development of ebselen and silver ion as antibacterial agents for treatment of MDR UPEC infections. [ABSTRACT FROM AUTHOR]

Isoflavonoid representatives such as genistein and daidzein are highly potent anticancer, antibacterial, and antioxidant agents. It have been demonstrated that methylation of flavonoids enhanced the transporting ability, which lead to facilitated absorption and greatly increased bioavailability. In this paper, genetically engineered Escherichia coli was reconstructed by harboring E. coli K12-derived metK encoding S-adenosine-l-methionine (SAM) synthase (accession number: K02129) for enhancement of SAM as a precursor and Streptomyces avermitilis originated SaOMT2 (O-methyltransferase, accession number: NP&#95;823558) for methylation of daidzein and genistein as preferred substrates. The formation of desired products via biotransformation including 4'-O-methyl-genistein and 4'-O-methyl-daidzein was confirmed individually by using chromatographical methods such as high-performance liquid chromatography, liquid chromatography/time-of-flight/mass spectrometry (LC-TOF-MS), and nuclear magnetic resonance (NMR), and NMR ( 1 H and 13 C). Furthermore, substrates concentration, incubation time, and media parameters were optimized using flask culture. Finally, the most fit conditions were applied for fed-batch fermentation with scale-up to 3 L (working volume) to obtain the maximum yield of the products including 164.25 µM (46.81 mg/L) and 382.50 µM (102.88 mg/L) for 4'-O-methyl genistein and 4'-O-methyl daidzein, respectively. In particular, potent inhibitory activities of those isoflavonoid methoxides against the growth of cancer line (B16F10, AGS, and HepG2) and human umbilical vein endothelial cells were investigated and demonstrated. Taken together, this research work described the production of isoflavonoid-4'-O-methoxides by E. coli engineering, improvement of production, characterization of produced compounds, and preliminary in vitro biological activities of the flavonoids being manufactured., (© 2015 International Union of Biochemistry and Molecular Biology, Inc.)

Summary: Some human antibodies may paradoxically inhibit complement activation on bacteria and enhance pathogen survival in humans. This property was also claimed for IgG antibodies reacting with terminal galactose‐α‐1,3‐galactose (Galα3Gal; IgG anti‐αGal), a naturally occurring and abundant antibody in human plasma that targets numerous different pathogens. To reinvestigate these effects, we used IgG anti‐αGal affinity isolated from a pool of normal human IgG and human hypogammaglobulinaemia serum as a complement source. Flow cytometry was performed to examine antibody binding and complement deposition on pig erythrocytes, Escherichia coli O86 and Streptococcus pneumoniae serotype 9V. Specific nanobodies were used to block the effect of single complement factors and to delineate the complement pathways involved. IgG anti‐αGal was capable of activating the classical complement pathway on all the tested target cells. The degree of activation was exponentially related to the density of bound antibody on E. coli O86 and pig erythrocytes, but more linearly on S. pneumoniae 9V. The alternative pathway of complement amplified complement deposition. Deposited C3 fragments covered the activating IgG anti‐αGal, obstructing its detection and highlighting this as a likely general caveat in studies of antibody density and complement deposition. The inherent capacity for complement activation by the purified carbohydrate reactive IgG anti‐αGal was similar to that of normal human IgG. We propose that the previously reported complement inhibition by IgG anti‐αGal relates to suboptimal assay configurations, in contrast to the complement activating property of the antibodies demonstrated in this paper. [ABSTRACT FROM AUTHOR]

As a reactive intermediate, chloracetyl chitosan oligosaccharide (CACS) can be nucleophilic substituted by some bioactive groups to give novel derivatives of chitosan oligosaccharide (COS). The Schiff bases of pyridine‐4‐aldehyde are grafted onto CACS to give four COS derivatives in this paper. Specific structural characterization is implemented by fourier‐transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The degree of substitution (DS) of COS derivatives is quantitatively calculated by ratio of hydrogen proton integral. Their antioxidant property is evaluated using free radical scavenging assay towards 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and superoxide anion radicals, and the antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) is also investigated. The results revealed that the pyridine‐4‐aldehyde Schiff bases grafted chloracetyl chitosan oligosaccharide derivatives showed better antioxidant activity as well as antibacterial activity than COS and CACS, which may be related to the positive charge of these derivatives. Among all final products, derivative BPCACS with the highest DS has the best bioactivity with scavenging rate of 91.49% for the DPPH assay and inhibition diameter of 39.25 mm for S. aureus inhibitory assay, respectively. These results indicated that COS derivatives with enhanced biological activities could serve as potential biomaterial for antioxidant and antibacterial applications. [ABSTRACT FROM AUTHOR]

The rise of antibiotic resistance poses a significant public health crisis, particularly due to limited antimicrobial options for the treatment of infections with Gram‐negative pathogens. Here, an antimicrobial peptide (AMP) SR25 is characterized, which effectively kills both Gram‐negative and Gram‐positive bacteria through a unique dual‐targeting mechanism without detectable resistance. Meanwhile, an SR25‐functionalized hydrogel is developed for the efficient treatment of infected diabetic wounds. SR25 is obtained through genome mining from an uncultured bovine enteric actinomycete named Nonomuraea Jilinensis sp. nov. Investigations reveal that SR25 has two independent cellular targets, disrupting bacterial membrane integrity and restraining the activity of succinate:quinone oxidoreductase (SQR). In a diabetic mice wound infection model, the SR25‐incorporated hydrogel exhibits high efficacy against mixed infections of Escherichia coli (E. coli) and methicillin‐resistant Staphylococcus aureus (MRSA), accelerating wound healing. Overall, these findings demonstrate the therapeutic potential of SR25 and highlight the value of mining drugs with multiple mechanisms from uncultured animal commensals for combating challenging bacterial pathogens. [ABSTRACT FROM AUTHOR]

Although antimicrobial dressings have proven to be crucial in the treatment of wounds, they may give rise to antibiotic‐resistant strains or result in the release of endotoxins after bacterial death, which in turn inhibits wound healing. This study highlights the efficacy of a novel alumina ceramic textile as dressing that utilizes the principles of bacteria capture from the wound bed and inhibition of bacterial infiltration into the wound bed to reduce the bacterial burden and to inhibit the spread of infection, without the involvement of active antimicrobial substances or functional nanoparticles. The alumina textiles are compared to commercial dressings like the non‐woven mesh Cutimed Sorbact and gauzes from LEINA WERKE and performed significantly better in capturing bacteria. They are found to be effective against both Gram‐negative Escherichia coli and Gram‐positive Bacillus subtilis and show promising results in the presence of simulated wound fluid and in artificial wound bed tests from which they can be easily lifted without leaving behind any visible residues. In summary, the alumina textiles exhibit a highly efficient bacterial binding activity, possibly due to the intrinsic material properties of their hierarchical structure including the tricot knit mesh, small fiber diameters, pronounced fiber surface microtopography, and high specific surface area. [ABSTRACT FROM AUTHOR]

The dynamics of swimming microorganisms is strongly affected by solid-liquid and air-liquid interfaces. In this paper, we characterize the motion of both single bacteria and microcolonies at an air-liquid interface. Both of them follow circular trajectories. Single bacteria preferentially show a counter-clockwise motion, in agreement with previous experimental and theoretical findings. Instead, no preferential rotation direction is observed for microcolonies suggesting that their motion is due to a different physical mechanism. We propose a simple mechanical model where the microcolonies move like rafts constrained to the air-liquid interface. Finally, we observed that the microcolony growth is due to the aggregation of colliding single-swimmers, suggesting that the microcolony formation resembles a condensation process where the first nucleus originates by the collision between two single-swimmers. Implications of microcolony splitting and aggregation on biofilm growth and dispersion at air-liquid interface are discussed., (© 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

Pyruvate decarboxylase (PDC) is responsible for the decarboxylation of pyruvate, producing acetaldehyde and carbon dioxide and is of high interest for industrial applications. PDC is a very powerful tool in the enzymatic synthesis of chiral amines by combining it with transaminases when alanine is used as amine donor. However, one of the main drawback that hampers its use in biocatalysis is its production and the downstream processing on scale. In this paper, a production process of PDC from Zymobacter palmae has been developed. The enzyme has been cloned and overexpressed in Escherichia coli. It is presented, for the first time, the evaluation of the production of recombinant PDC in a bench‐scale bioreactor, applying a substrate‐limiting fed‐batch strategy which led to a volumetric productivity and a final PDC specific activity of 6942 U L−1h−1 and 3677 U gDCW−1 (dry cell weight). Finally, PDC was purified in fast protein liquid chromatography equipment by ion exchange chromatography. The developed purification process resulted in 100% purification yield and a purification factor of 3.8. [ABSTRACT FROM AUTHOR]

Summary: Different codon optimization algorithms are available that aim at improving protein production by optimizing translation elongation. In these algorithms, it is generally not considered how the altered protein coding sequence will affect the secondary structure of the corresponding RNA transcript, particularly not the effect on the 5′‐UTR structure and related ribosome binding site availability. This is a serious drawback, because the influence of codon usage on mRNA secondary structures, especially near the start of a gene, may strongly influence translation initiation. In this study, we aim to reduce the effect of codon usage on translation initiation by applying a bicistronic design (BCD) element. Protein production of several codon‐optimized gene variants is tested in parallel for a BCD and a standard monocistronic design (MCD). We demonstrate that these distinct architectures can drastically change the relative performance of different codon optimization algorithms. We conclude that a BCD is indispensable in future studies that aim to reveal the impact of codon optimization and codon usage correlations. Furthermore, irrespective of the algorithm used, using a BCD does improve protein production compared with an MCD. The overall highest expression from BCDs for both GFP and RFP is at least twofold higher than the highest levels found for the MCDs, while for codon variants having very low expression from the MCD, even 10‐fold to 100‐fold increases in expression were achieved by the BCD. This shows the great potential of the BCD element for recombinant protein production. This paper outlines the improved protein expression when using a bicistronic design (BCD) in Escherichia coli. Additionally, the decoupling of translation initiation from translation elongation by a BCD changes the relative performance of different codon optimization algorithms. [ABSTRACT FROM AUTHOR]

Summary: Type II toxin‐antitoxin (TA) modules, which are important cellular regulators in prokaryotes, usually encode two proteins, a toxin that inhibits cell growth and a nontoxic and labile inhibitor (antitoxin) that binds to and neutralizes the toxin. Here, we demonstrate that the res‐xre locus from Photorhabdus luminescens and other bacterial species function as bona fide TA modules in Escherichia coli. The 2.2 Å crystal structure of the intact Pseudomonas putida RES‐Xre TA complex reveals an unusual 2:4 stoichiometry in which a central RES toxin dimer binds two Xre antitoxin dimers. The antitoxin dimers each expose two helix‐turn‐helix DNA‐binding domains of the Cro repressor type, suggesting the TA complex is capable of binding the upstream promoter sequence on DNA. The toxin core domain shows structural similarity to ADP‐ribosylating enzymes such as diphtheria toxin but has an atypical NAD+‐binding pocket suggesting an alternative function. We show that activation of the toxin in vivo causes a depletion of intracellular NAD+ levels eventually leading to inhibition of cell growth in E. coli and inhibition of global macromolecular biosynthesis. Both structure and activity are unprecedented among bacterial TA systems, suggesting the functional scope of bacterial TA toxins is much wider than previously appreciated. Toxin‐antitoxin (TA) modules specify small protein‐protein or protein‐RNA complexes that help bacteria overcome challenging environmental conditions. In this paper, we show that the RES‐Xre TA module has a highly unusual three‐dimensional structure in that each toxin binds two antitoxins. We also show that the RES toxin reduces cellular NAD+ levels, causing wide‐ranging effects on bacterial metabolism. [ABSTRACT FROM AUTHOR]

As a model system, Escherichia coli has been used to study various life processes. A dramatic paradigm shift has occurred in recent years, with the study of single proteins moving toward the study of dynamically interacting proteins, especially protein-protein interaction (PPI) networks. However, despite the importance of PPI networks, little is known about the intrinsic nature of the network structure, especially high-dimensional topological properties. By introducing general hypergeometric distribution, we reconstruct a statistically reliable combined PPI network of E. coli (E. coli-PPI-Network) from several datasets. Unlike traditional graph analysis, algebraic topology was introduced to analyze the topological structures of the E. coli-PPI-Network, including high-dimensional cavities and cycles. Random networks with the same node and edge number (RandomNet) or scale-free networks with the same degree distribution (RandomNet-SameDD) were produced as controls. We discovered that the E. coli-PPI-Network had special algebraic typological structures, exhibiting more high-dimensional cavities and cycles, compared to RandomNets or, importantly, RandomNet-SameDD. Based on these results, we defined degree of involved q-dimensional cycles of proteins (q-DCprotein) in the network, a novel concept that relies on the integral structure of the network and is different from traditional node degree or hubs. Finally, top proteins ranked by their 1-DCprotein were identified (such as gmhB, rpoA, rplB, rpsF and yfgB). In conclusion, by introducing mathematical and computer technologies, we discovered novel algebraic topological properties of the E. coli-PPINetwork, which has special high-dimensional cavities and cycles, and thereby revealed certain intrinsic rules of information flow underlining bacteria biology. [ABSTRACT FROM AUTHOR]

The levels of aeration and mass transfer are critical parameters required for an efficient aerobic bioprocess, and directly depend on the design features of exploited bioreactors. A novel apparatus, using gas vortex for aeration and mass transfer processes, was constructed in the Center of Vortex Technologies (Novosibirsk, Russia). In this paper, we compared the efficiency of recombinant Escherichia coli strain cultivation using novel gas-vortex technology with conventional bioprocess technologies such as shake flasks and bioreactors with mechanical stirrers. We demonstrated that the system of aeration and agitation used in gas-vortex bioreactors provides 3.6 times higher volumetric oxygen transfer coefficient in comparison with mechanical bioreactor. The use of gas-vortex bioreactor for recombinant E. coli strain cultivation allows to increase the efficiency of target protein expression at 2.2 times for BL21(DE3)/pFK2 strain and at 3.5 times for auxotrophic C600/pRT strain (in comparison with stirred bioreactor)., (© 2016 International Union of Biochemistry and Molecular Biology, Inc.)

Building a robust, stable network must include strategies to minimize perturbations caused by environmental stress, while optimizing cellular fitness. The introduction of oxygen into the Earth's atmosphere brought challenges for the microbes that had evolved enzyme machinery and metabolic network stability in the anoxic world. Unable to generate new enzyme paradigms and metabolic networks de novo, organisms have evolved strategies to neutralize the impact of oxygen that can be added to and integrated into the existing metabolic framework. This issue of Molecular Microbiology includes a paper by Korshunov et al. in which the authors describe an elegant strategy that Escherichia coli has evolved to minimize metabolic stress that results from the acquisition and use of cystine, the oxidized form of cysteine, as a source of cellular sulfur. This study highlights how a strategy involving both cost and benefit can result in a functional, but energy intensive mechanism for this bacterium to thrive in an oxic world. [ABSTRACT FROM AUTHOR]

Publishers note on the paper ctpp.201800106 "Deactivation of I Escherichia coli i with different volumes in drinking water using cold atmospheric plasma" by G. Asadollahfardi et al. The Acknowledgment section should read: B ACKNOWLEDGMENTS b The authors thank Dr. M. Amini (Plasma Physics Research Centre, Science and Research Branch, Islamic Azad University, Tehran, Iran) for the preparation of the SEM images. [Extracted from the article]