Chromosome recombination and modification by LoxP-mediated evolution in Vibrio natriegens using CRISPR-associated transposases.

Chromosome rearrangement by LoxP-mediated evolution has emerged as a powerful approach to studying how chromosome architecture impacts phenotypes. However, it relies on the in vitro synthesis of artificial chromosomes. The recently reported CRISPR-associated transposases (CASTs) held great promise for the efficient insertion of abundant LoxP sites directly onto the genome of wild-type strains. In this study, with the fastest-growing bacterium Vibrio natrigens (V. natriegens) as an object, a multiplex genome integration tool derived from CASTs was employed to achieve the insertion of cargo genes at eight specific genomic loci within 2 days. Next, we introduced 30 LoxP sites onto chromosome 2 (Chr2) of V. natriegens. Rigorously induced Cre recombinase was used to demonstrate Chromosome Rearrangement and Modification by LoxP-mediated Evolution (CRaMbLE). Growth characterization and genome sequencing showed that the ~358 kb fragment on Chr2 was accountable for the rapid growth of V. natriegens. The enabling tools we developed can help identify genomic regions that influence the rapid growth of V. natriegens without a prior understanding of genome mechanisms. This groundbreaking demonstration may also be extended to other organisms such as Escherichia coli, Pseudomonas putida, Bacillus subtilis, and so on.

Study on a rotational symmetry structure pulse forming network with low-impedance for compact pulse drivers.

A pulse forming network (PFN) is a significant component, contributing a lot to the overall dimension of pulse generators. In order to both reduce the size of PFN and improve the output waveform quality, this paper proposes a compact low-impedance PFN with a rotational symmetry structure. The PFN consists of four groups of Blumlein pulse forming units (PFUs) connected in parallel along the angular direction, and the spline curve structure is applied in each PFU, which achieves a higher space utilization rate. The theoretical maximum energy density of PFN is 6.6 J/L as the dimensions of PFN are φ500 × 138 mm. Field-circuit co-simulation is carried out based on the spatial model of PFN and the double switch modulation circuit to analyze the effects of switch delay time (time between main switch and steep discharge switch), as well as the output port position affecting the output pulse waveform. The results show that the PFN is appropriate to achieve quasi-square wave pulse modulation as the switch delay time is 290 ns with the output port positioned at the periphery. The verification experiments are also carried out. The results show that the PFN can generate a quasi-square wave pulse with an output voltage of 49.6 kV, a pulse width of 83 ns, and a peak power of 1 GW on a matched load. The output pulse exhibits a distinct flat top, with the fluctuation of the plateau being less than 3%.

Dynamic characteristics of a coaxial magnetic switch modulating pulse forming networks.

Pulsed power generators utilizing magnetic switch technology within the 100 ns scale have become widespread for surface treatment, high power microwave generation, and food processing, in which the dynamic characteristics of the magnetic switch perform an important function. The saturation process, electric field between layers, and energy loss are closely associated with the applied time scale of the magnetic core, which affects the dynamic characteristics of the switch. However, compared with the study within the microsecond scale, the dynamic characteristics of magnetic switches within the 100 ns scale have not been studied in depth. In this paper, the dynamic characteristics of a coaxial magnetic switch modulating pulse forming networks (PFNs) are studied via both field-loop co-simulation and scaled experimental test. It is found that increasing PFN section number (Ns) leads to an acceleration in the saturation process of the core, which helps understand the switch performance of the magnetic core more clearly. With respect to a specific magnetic switch based on a ferromagnetic core, it is quantitatively analyzed that increasing Ns from 1 to 10 leads to a 16.1% reduction in core saturation time (tsat), a 13.4% increase in eddy loss (EET), and a 5.7% rise in maximum interlamination field strength (Emax) under the 100 ns scale; however, tsat is reduced by 19.3%, EET increases by 5.2%, and Emax rises by 2.3% under the microsecond scale. The results could provide a design reference for magnetic switches in pulsed power generators.

Silkworm Cocoon: Dual Functions as a Traditional Chinese Medicine and the Raw Material of Promising Biocompatible Carriers.

The silkworm cocoon (SC), both as a traditional Chinese medicine and as the raw material for biocompatible carriers, has been extensively used in the medical and biomedical fields. This review elaborates on the multiple functions of SC, with an in-depth analysis of its chemical composition, biological activities, as well as its applications in modern medicine. The primary chemical components of SC include silk fibroin (SF), silk sericin (SS), and other flavonoid-like bioactive compounds demonstrating various biological effects. These include hypoglycemic, cardioprotective, hypolipidemic, anti-inflammatory, antioxidant, and antimicrobial actions, which highlight its potential therapeutic benefits. Furthermore, the review explores the applications of silk-derived materials in drug delivery systems, tissue engineering, regenerative medicine, and in vitro diagnostics. It also highlights the progression of SC from laboratory research to clinical trials, emphasizing the safety and efficacy of SC-based materials across multiple medical domains. Moreover, we discuss the market products developed from silk proteins, illustrating the transition from traditional uses to contemporary medical applications. This review provides support in understanding the current research status of SC and the further development and application of its derived products.

Identification and characterization of multiple novel picornaviruses in fecal samples of bar-headed goose.

Introduction: The bar-headed goose (Anser indicus), one of the most well-known high-altitude birds, is renowned for its adaptation to high-altitude environments. Previous studies have shown that they can be infected with highly pathogenic avian influenza; however, there is currently limited research on other viruses in bar-headed geese. Methods: In this study, 10 fecal samples of healthy bar-headed geese were collected, and viral metagenomics method was conducted to identify novel picornaviruses. Results: Seven novel picornaviruses were identified in the fecal samples of bar-headed geese. Most of these picornaviruses were genetically different from other currently known viruses in the NCBI dataset. Among them, PICV4 was determined to be a new species belonging to the Anativirus genus, PICV5 and PICV13 were classified as novel species belonging to the Hepatovirus genus, and the remaining four picornaviruses (PICV1, PICV19, PICV21, and PICV22) were identified as part of the Megrivirus A species of the Megrivirus genus. Recombinant analysis indicates that PICV21 was a potential recombinant, and the major and minor parents were PICV1 and PICV22, respectively. Conclusion: The findings of this study increase our understanding of the diversity of picornaviruses in bar-headed geese and provide practical viral genome information for the prevention and treatment of potential viral diseases affecting this species.