Application of a rapid and sensitive RPA-CRISPR/Cas12a assay for naked-eye detection of Haemophilus parasuis.

BACKGROUND: Haemophilus parasuis (H. parasuis) is a gram-negative bacterial pathogen that causes severe infections in swine, resulting in substantial economic losses. Currently, the majority of H. parasuis detection methods are impractical for on-site application due to their reliance on large instruments or complex procedures. Thus, there is an urgent need to develop a rapid, visually detectable, and highly sensitive detection method, especially under resource-limited environments and field conditions. RESULTS: In this study, we established a naked eye assay for highly sensitive detection by combining recombinase polymerase amplification (RPA) with CRISPR/Cas12a technology. Positive samples exhibited a clear red color visible to the naked eye, while negative samples appeared blue. We achieved a remarkable sensitivity, detecting H. parasuis down to a single copy, with no cross-reactivity with other bacteria. In a mouse model, our assay detected H. parasuis infection nearly 8 h earlier than traditional PCR. Compared to qPCR, our detection results were 100 % accurate. To enhance point-of-care applicability and mitigate the risk of aerosol contamination from uncapping, we consolidated RPA and CRISPR/Cas12a cleavage into a single-tube reaction system. This integrated approach was validated with 20 clinical lung samples, yielding results consistent with those obtained from qPCR. The entire procedure, from DNA extraction to detection, was completed in 35 min. SIGNIFICANCE: We present an RPA-CRISPR/Cas12a assay suitable for the early and resource-efficient diagnosis of H. parasuis infections. Its simplicity and visual detection are advantageous for field diagnostics, representing a substantial develpoment in the diagnosis of H. parasuis.

Barnacle-Inspired Wet Tissue Adhesive Hydrogels with Inherent Antibacterial Properties for Infected Wound Treatment.

Currently, antibiotics are the most common treatment for bacterial infections in clinical practice. However, with the abuse of antibiotics and the emergence of drug-resistant bacteria, the use of antibiotics has faced an unprecedented challenge. It is imminent to develop nonantibiotic antimicrobial agents. Based on the cation-π structure of barnacle cement protein, a polyphosphazene-based polymer poly[(N,N-dimethylethylenediamine)-g-(N,N,N,N-dimethylaminoethyl p-ammonium bromide (ammonium bromide)-g-(N,N,N,N-dimethylaminoethyl acetate ethylammonium bromide)] (PZBA) with potential adhesion and inherent antibacterial properties was synthesized, and a series of injectable antibacterial adhesive hydrogels (PZBA-PVA) were prepared by cross-linking with poly(vinyl alcohol) (PVA). PZBA-PVA hydrogels showed good biocompatibility, and the antibacterial rate of the best-performed hydrogel reached 99.81 ± 0.04% and 98.80 ± 2.16% against Staphylococcus aureus and Escherichia coli within 0.5 h in vitro, respectively. In the infected wound model, the healing rate of the PZBA-PVA-treated group was significantly higher than that of the Tegaderm film group due to the fact that the hydrogel suppressed inflammatory responses and modulated the infiltration of immune cells. Moreover, the wound healing mechanism of the PZBA-PVA hydrogel was further evaluated by real-time polymerase chain reaction and total RNA sequencing. The results indicated that the process of hemostasis and tissue development was prompted and the inflammatory and immune responses were suppressed to accelerate wound healing. Overall, the PZBA-PVA hydrogel is shown to have the potential for infected wound healing application.

Genome-wide map of R-loops reveals its interplay with transcription and genome integrity during germ cell meiosis.

INTRODUCTION: The R-loop is a naturally formed three-strand nucleic acid structure that recently has been reported to participate in multiple biological processes and helped answer some previously unexplained scientific questions. Meiosis process involves multiple chromatin-related events such as DNA double-stranded breaks (DSB) formation, repairing and transcriptional dynamics. OBJECTIVES: Explore the regulatory roles and physiological functions of R-loops in the mammalian meiosis process. METHODS: In our study, using genome-wide S9.6 CUT & Tag seq, we first mapped the genomic distribution and dynamic changes of R-loop during the meiotic process in mice, from spermatogonia to secondary spermatocytes. And we further explore the role of R-loop in physiological conditions by constructing conditional knockout mice of Rnaseh1, which deleted the R-loop endonuclease before meiosis entry. RESULTS: R-loop predominantly distributes at promoter-related regions and varies across different meiotic stages. By joint analysis with the corresponding transcriptome, we found that the R-loop was closely related to transcription during the meiotic process. The high frequency of promoter-related R-loop in meiotic cells is usually accompanied by high transcription activity, and we further verified this in the leptotene/zygotene to the pachytene transition process. Moreover, the lack of RNase H1 caused sterility in male mice with R-loop accumulation and abnormal DSB repair in spermatocytes. Further analysis showed that abnormal R-loop accumulation in the leptotene/zygotene stages influenced transcriptional regulation in the pachytene stage. CONCLUSION: The mutual regulation of the R-loop and transcription plays an essential role in spermatogenesis. And R-loop is also important for the normal repair process of DSB during meiosis.

A honeybee stinger-inspired self-interlocking microneedle patch and its application in myocardial infarction treatment.

Weak tissue adhesion remains a major challenge in clinical translation of microneedle patches. Mimicking the structural features of honeybee stingers, stiff polymeric microneedles with unidirectionally backward-facing barbs were fabricated and embedded into various elastomer films to produce self-interlocking microneedle patches. The spirality of the barbing pattern was adjusted to increase interlocking efficiency. In addition, the micro-bleeding caused by microneedle puncturing adhered the porous surface of the patch substrate to the target tissue via coagulation. In the demonstrative application of myocardial infarction treatment, the bioinspired microneedle patches firmly fixed on challenging beating hearts, significantly reduced cardiac wall stress and strain in the infarct, and maintained left ventricular function and morphology. In addition, the microneedle patch was minimally invasively implanted onto beating porcine heart in 10 minutes, free of sutures and adhesives. Therefore, the honeybee stinger-inspired microneedles could provide an adaptive and convenient means to implant patches for various medical applications. STATEMENT OF SIGNIFICANCE: Adhesion between tissue and microneedle patches with smooth microneedles is usually weak. We introduce a novel barbing method of fabricating unidirectionally backward facing barbs with controllable spirality on the microneedles on microneedle patches. The microneedle patches self-interlock on mechanically dynamic beating hearts, similar to honeybee stingers. The micro-bleeding and coagulation on the porous surface provide additional adhesion force. The microneedle patches attenuate left ventricular remodeling via mechanical support and are compatible with minimally invasive implantation.

Injection route affects intra-articular hyaluronic acid distribution and clinical outcome in viscosupplementation treatment for knee osteoarthritis: a combined cadaver study and randomized clinical trial.

The coverage of hyaluronic acid (HA) on the impaired cartilage should be the precondition to exert its beneficial effect on knee osteoarthritis (KOA) according to the pharmacological mechanism. However, the intra-articular distribution of HA might be correlated with the route of drug delivery. Forty-two cadaver knees with radiographic evidence of osteoarthritis were given anteromedial (AM) or medial midpatellar (MMP) injection of HA (molecular weight 600-1500 kD) followed by gait stimulation. Although 2.5 ml HA delivered through both routes failed to cover the entire cartilage, HA covered 96.12% cartilage of patellofemoral joint (PFJ) and 71.44% of medial femorotibial joint (FTJ) through MMP route, whereas mainly distributed into FTJ and posterior condyles through AM route. HA in the MMP group distributed more in PFJ than that in the AM group (P < 0.001), but no significant difference presented in medial FTJ (P = 0.084). The clinical efficacy was also associated with the route of drug delivery. One hundred patients with unilateral mild-to-moderate KOA were recruited and randomly assigned to receive five weekly HA injections with AM route (n = 50) or MMP route (n = 50). Patients in the MMP group obtained better improvement in WOMAC index total score, pain score, stiffness score, and Lequesne index total score over the entire follow-up period, as compared to patients in the AM group (all P < 0.01). More patients in the MMP group claimed pain relief (71.7%, P = 0.024) and felt satisfying (63.1%, P = 0.007) than in the AM group at the end of follow-up. Therefore, intra-articular HA injection through MMP route is recommended in treating mild-to-moderate KOA. Graphical Abstract .

[Hyaluronate acid for treatment of chondromalacia patellae: a 52-week follow-up study].

OBJECTIVE: To assess the therapeutic effect of hyaluronate acid (HA) injection through the subpatellar route for treatment of chondromalacia patellae (CP). METHODS: Eighty-eight patients with the diagnosis of CP were enrolled in this prospective study, including 38 with early CP (CP group) and 50 with advanced CP (patellofemoral arthritis group) diagnosed based on image presentations. All the patients received intra-articular HA injections through a subpatellar route once a week for 5 consecutive weeks. The primary outcome measures included WOMAC index scores and Lequesne scores before and at 4, 12, 26 and 52 weeks after the injections. The secondary outcome measures included the 30-m walking time and stair ascending and descending time (one floor) before and at 1, 2, 3, and 4 weeks after the injections. RESULTS: In both groups the patients showed significantly decreased WOMAC scores and Lequesne scores at 4, 12, 26 and 52 weeks after HA injections as compared with the baseline scores (all P < 0.01). No significant difference was found between the two groups in WOMAC scores and Lequesne scores at 4 or 12 weeks after the injections (both P>0.05). The WOMAC scores and Lequesne scores at 26 and 52 weeks after the injections were significantly higher in patellofemoral arthritis group than in CP group (both P < 0.05). In both groups, the 30-m walking time and the stair ascending and descending time decreased significantly at 1, 2, 3, and 4 weeks after HA injections (all P < 0.05) without significant differences between the two groups (all P>0.05). CONCLUSIONS: HA injection through the subpatellar route is effective for treatment of CP. HA injection produces better long-term efficacy for treatment of early CP than for advanced CP where patellofemoral arthritis occurs.