Genetic and Phenotypic Analysis of Phage-Resistant Mutant Fitness Triggered by Phage-Host Interactions

The emergence of phage-resistant bacterial strains is one of the biggest challenges for phage therapy. However, the emerging phage-resistant bacteria are often accompanied by adaptive trade-offs, which supports a therapeutic strategy called "phage steering". The key to phage steering is to guide the bacterial population toward an evolutionary direction that is favorable for treatment. Thus, it is important to systematically investigate the impacts of phages targeting different bacterial receptors on the fitness of the bacterial population. Herein, we employed 20 different phages to impose strong evolutionary pressure on the host Pseudomonas aeruginosa PAO1 and examined the genetic and phenotypic responses of their phage-resistant mutants. Among these strains with impaired adsorptions, four types of mutations associated with bacterial receptors were identified, namely, lipopolysaccharides (LPSs), type IV pili (T4Ps), outer membrane proteins (OMPs), and exopolysaccharides (EPSs). PAO1, responding to LPS- and EPS-dependent phage infections, mostly showed significant growth impairment and virulence attenuation. Most mutants with T4P-related mutations exhibited a significant decrease in motility and biofilm formation ability, while the mutants with OMP-related mutations required the lowest fitness cost out of the bacterial populations. Apart from fitness costs, PAO1 strains might lose their resistance to antibiotics when counteracting with phages, such as the presence of large-fragment mutants in this study, which may inspire the usage of phage-antibiotic combination strategies. This work provides methods that leverage the merits of phage resistance relative to obtaining therapeutically beneficial outcomes with respect to phage-steering strategies.

Genomic characterization of the novel bacteriophage IME183, infecting Klebsiella pneumoniae of capsular type K2

Klebsiella pneumoniae causes a wide range of serious and life-threatening infections. Klebsiella phage IME183, isolated from hospital sewage, exhibited lytic activity against K. pneumoniae of capsular type K2. Transmission electron microscopy revealed that phage IME183 has a head with a diameter of 50 nm and a short tail. Its genome is 41,384 bp in length with a GC content of 52.92%. It is predicted to contain 50 open reading frames (ORFs). The results of evolutionary analysis suggest that phage IME183 should be considered a member of a new species in the genus Przondovirus.

Bank loan information and information asymmetry in the stock market: evidence from China

In this study, we use bank loan information to construct proxies for corporate transparency and examine whether these measures reflect information asymmetry in the stock market. Our analysis is based on a novel dataset of stock transactions and bank loans of all publicly listed firms on the Shenzhen Stock Exchange, covering January 2008 to June 2013. We find that firms with outstanding loans have a lower level of information asymmetry in the stock market, whereas firms with defaulted loans have a higher level of asymmetry. Further evidence demonstrates that the effect of loan default on information asymmetry in the stock market is more pronounced when these loans are borrowed from joint-equity commercial banks or multiple banks and when the default occurs under inactive market conditions. Our results remain robust to a series of endogeneity and sensitivity tests and provide suggestive evidence of a close connection between the credit loan and stock markets.

Characterization and Genomic Analysis of a Novel Drexlervirial Bacteriophage IME268 with Lytic Activity Against Klebsiella pneumoniae

Introduction

Klebsiella pneumoniae, a multidrug resistant bacterium, that causes nosocomial infections including septicemia, pneumonia etc. Bacteriophages are potential antimicrobial agents for the treatment of antibiotic resistant bacteria.

Methods and Results

In this study, a novel bacteriophage IME268 was isolated from hospital sewage against clinical multi-drug resistant Klebsiella pneumoniae. Transmission electron microscopy and genomic characterization of this phage exhibited it belongs to the Webervirus genus, Drexlerviridae family. Phage IME268 possessed a double-stranded DNA genome composed of 49,552bp with a GC content of 50.5%. The phage genome encodes 77 open reading frames, out of 44 are hypothetical proteins while 33 had assigned putative functions. No tRNA, virulence related or antibiotic resistance genes were found in phage genome. Comparative genomic analysis showed that phage IME268 has 95% identity with 87% query cover with other phages in NCBI database. Multiplicity of infection, one step growth curve and host range of phage were also measured.

Conclusion

According to findings, Phage IME268 is a promising biological agent that infects Klebsiella pneumoniae and can be used in future phage therapies.

Multiple attribute group decision-making based on interval-valued q-rung orthopair uncertain linguistic power Muirhead mean operators and linguistic scale functions

Fuzzy set theory and its extended form have been widely used in multiple-attribute group decision-making (MAGDM) problems, among which the interval-valued q-rung orthopair fuzzy sets (IVq-ROFSs) got a lot of attention for its ability of capturing information denoted by interval values. Based on the previous studies, to find a better solution for fusing qualitative quantization information with fuzzy numbers, we propose a novel definition of interval-valued q-rung orthopair uncertain linguistic sets (IVq-ROULSs) based on the linguistic scale functions, as well as its corresponding properties, such as operational rules and the comparison method. Furthermore, we utilize the power Muirhead mean operators to construct the information fusion method, and provide a variety of aggregation operators based on the proposed information description environment. A model framework is constructed for solving the MAGDM problem utilizing the proposed method. Finally, we illustrate the performance of the new method and investigate its advantages and superiorities through comparative analysis.