No abstract

Highlights d eCIS loci are widely distributed among bacteria genomes d eCIS loci encode phage-tail-like proteinaceous machines d eCIS superfamily is grouped into six families with distinct genetic features

Background Clinical characteristics (taxonomy, virulence genes and antimicrobial resistance ) of Aeromonas in isolated from extra-intestinal and intestinal infections were investigated to describe epidemiology, associated virulence factors and optimal therapy options. Methods Clinical samples ( n = 115) of Aeromonas were collected from a general hospital in Beijing between the period 2015 and 2017. Taxonomy was investigate by Multilocus phylogenetic analysis (MLPA), 10 putative virulence factors by use of polymerase chain reaction (PCR) and antimicrobial resistance to 15 antibiotics by use of the microbroth dilution method. Results The most common species of Aeromonas detected in samples of intestinal tract included; A. caviae (43.9%), A. veronii (35.7%), and A. dhakensis (12.2%). Prevalent species of Aeromonas collected from extra-intestinal infections included; A. hydrophila (29.4%), A. caviae (29.4%), and A. dhakensis (23.5%). A. hydrophila were detected in 1% of stool samples and 29.4% (5/17) of extra-intestinal infections. A. hydrophila strains in extra-intestinal infections were related to malignancy. The most common medical conditions among patients with Aeromonas infections included malignancy and liver-transplant related cholecystitis. Multiple drug resistance (MDR) was prevalent in extra-intestinal isolates (82.3%, 14/17) and was greater than the prevalence in intestinal isolates (30.6%, 30/98) ( P < 0.05). Resistant rates of extra-intestinal isolates were 70.6, 35.3, 23.5 and 5.9% for ceftriaxone, ciprofloxacin, gentamicin and imipenem, respectively, and were higher than found in previous studies. Despite differences in the number and type of virulence genes among samples of Aeromonas , no significant correlation was found between invasion and virulent genes in intestinal or extra-intestinal infections. Conclusions Overall results of this study support a role for Aeromonas spp. as a potential causative infectious agent of gastroenteritis, and malignancy, liver cirrhosis, post liver transplantation in immunocompromised patients. A. hydrophila was more prevalent in samples of extra-intestinal infections when compared to samples of intestinal infections, and was especially prominent in samples of patients presenting with malignancy. Aeromonas isolates from extra-intestinal samples had high rates of drug resistance but 3rd generation cephalosporins, fluoroquinolones and aminoglycosides remain as opti...

A considerable research effort is focused on developing effective delivery systems for hydrophobic nutraceuticals. β-carotene, a pro-vitamin A carotenoid, requires encapsulation to improve its water dispersibility and chemical stability in foods. In this study, β-carotene was encapsulated in oil-in-water nanoemulsions fabricated using high-pressure dual-channel microfluidization. Two types of natural emulsifier, quillaja saponins (Q-Naturale) and whey protein isolate (WPI), were capable of producing nanoemulsions (d=0.14-0.16μm) using this novel homogenization method. The physical and chemical stability of these nanoemulsions were characterized during storage at neutral pH conditions at refrigeration (4°C), ambient (25°C), and elevated (55°C) temperatures. At 4 and 25°C, all nanoemulsions remained physically stable throughout 14days storage, with little change in particle size or evidence of creaming. At 55°C, WPI nanoemulsions were also physically stable, but a small amount of droplet aggregation occurred in saponin nanoemulsions. The rate of β-carotene degradation increased with increasing storage temperature, but did not depend strongly on emulsifier type. This study showed that dual-channel microfluidization is an efficient method of continuously producing carotenoid-loaded nanoemulsions from natural emulsifiers. This knowledge may be useful for developing nutraceutical delivery systems for application within commercial food, beverage, and pharmaceutical products.

A class of 2D layered materials exhibits substantial potential for high‐performance electrocatalysts due to high specific surface area, tunable electronic properties, and open 2D channels for fast ion transport. However, liquid‐phase exfoliation always utilizes organic solvents that are harmful to the environment, and the active sites are limited to edge sites. Here, an environmentally friendly exfoliator in aqueous solution is presented without utilizing any toxic or hazardous substance and active site self‐assembly on the inert base of 2D materials. Benefiting from thin 2D/2D heterostructure and strong interfacial coupling, the resultant highly disordered amorphous NiFe/2D materials (Ti3C2 MXene, graphene and MoS2) thin nanosheets exhibit extraordinary electrocatalytic performance toward oxygen evolution reaction (OER) in alkaline media. DFT results further verify the experimental results. The study emphasizes a viable idea to probe efficient electrocatalysts by means of the synergistic effect of environmentally friendly exfoliator in aqueous solution and active site self‐assembly on the inert base of 2D materials which forms the unique thin 2D/2D heterostructure in‐suit. This new type of heterostructure opens up a novel avenue for the rational design of highly efficient 2D materials for electrocatalysis.

The fabrication of concentrated oil-in-water emulsions is useful for reducing storage and transportation costs, as well as for providing desirable textural, optical, stability, and release characteristics in commercial products. In this study, 50wt% oil-in-water emulsions were produced from natural emulsifiers using high-pressure dual-channel microfluidization (89.6MPa, 1 pass). The particle size and charge characteristics of emulsions stabilized using a hydrophilic biosurfactant (quillaja saponin) or mixtures of hydrophilic and hydrophobic biosurfactants (quillaja saponin+soy lecithin) were measured. The physical stability of the emulsions was determined during storage under quiescent conditions (pH7, 25°C). The mean droplet diameter and polydispersity decreased with increasing hydrophilic and hydrophobic biosurfactant concentration. Surface potential measurements indicated that interfacial composition depended on the amount of hydrophilic and hydrophobic biosurfactant present. The inclusion of hydrophobic emulsifier in the oil phase and hydrophilic emulsifier in the aqueous phase prior to homogenization, led to the formation of smaller oil droplets than using the hydrophilic emulsifier alone. The relatively small size and polydispersity of the droplets in the mixed-emulsifier systems led to a higher emulsion viscosity and a better aggregation stability, i.e., there was a smaller change in particle size during storage. However, some creaming was still observed in the emulsions due to the presence of a fraction of relatively large droplets. In summary, concentrated emulsions stabilized by mixed biosurfactants may be advantageous for commercial application in certain food, beverage, and pharmaceutical products.

Regarded as an emerging diarrheal micropathogen, Vibrio cholerae serogroup O139 was first identified in 1992 and has become an important cause of cholera epidemics over the last two decades. O139 strains have been continually isolated since O139 cholera appeared in China in 1993, from sporadic cases and dispersed foodborne outbreaks, which are the common epidemic types of O139 cholera in China. Antibiotic resistance profiles of these epidemic strains are required for development of clinical treatments, epidemiological studies and disease control. In this study, a comprehensive investigation of the antibiotic resistance of V. cholerae O139 strains isolated in China from 1993 to 2009 was conducted. The initial O139 isolates were resistant to streptomycin, trimethoprim-sulfamethoxazole and polymyxin B only, while multidrug resistance increased suddenly and became common in strains isolated after 1998. Different resistance profiles were observed in the isolates from different years. In contrast, most V. cholerae O1 strains isolated in the same period were much less resistant to these antibiotics and no obvious multidrug resistance patterns were detected. Most of the non-toxigenic strains isolated from the environment and seafood were resistant to four antibiotics or fewer, although a few multidrug resistant strains were also identified. These toxigenic O139 strains exhibited a high prevalence of the class I integron and the SXT element, which were rare in the non-toxigenic strains. Molecular subtyping of O139 strains showed highly diverse pulsed-field gel electrophoresis patterns, which may correspond to the epidemic state of sporadic cases and small-scale outbreaks and complex resistance patterns. Severe multidrug resistance, even resistance transfers based on mobile antibiotic resistance elements, increases the probability of O139 cholera as a threat to public health. Therefore, continual epidemiological and antibiotic sensitivity surveillance should focus on the occurrence of multidrug resistance and frequent microbial population shifts in O139 strains.

The natural liver extracellular matrix (ECM) achieved by decellularization holds great potential in the fields of tissue engineering and regenerative medicine. Additionally, the use of crosslinking agents on the ECM to stabilize its ultrastructure and enhance scaffold durability is gaining interest in tissue engineering. The objective of this study was to compare the scaffold properties of porcine liver ECM crosslinked with different agents (glutaraldehyde, genipin, and quercetin) to find the best strategy for producing a decellularized matrix with optimal and stable characteristics for transplantation and regeneration. The properties examined include mechanical properties, material stability, immunogenicity, and angiogenic capacity. Scaffolds were implanted into the greater omentum of rats, and their abilities to induce immune cell subpopulation invasion and neovascularization were evaluated. The results show that genipin crosslinking of decellularized liver matrices increased the mechanical and proangiogenic properties and reduced the inflammatory response in vivo.