Peg Precipitation Coupled with Chromatography is a New and Sufficient Method for the Purification of Botulinum Neurotoxin Type B

Clostridium botulinum neurotoxins are used to treat a variety of neuro-muscular disorders, as well as in cosmetology. The increased demand requires efficient methods for the production and purification of these toxins. In this study, a new purification process was developed for purifying type B neurotoxin. The kinetics of C.botulinum strain growth and neurotoxin production were determined for maximum yield of toxin. The neurotoxin was purified by polyethylene glycol (PEG) precipitation and chromatography. Based on design of full factorial experiment, 20% (w/v) PEG-6000, 4°C, pH 5.0 and 0.3 M NaCl were optimal conditions to obtain a high recovery rate of 87% for the type B neurotoxin complex, as indicated by a purification factor of 61.5 fold. Furthermore, residual bacterial cells, impurity proteins and some nucleic acids were removed by PEG precipitation. The following purification of neurotoxin was accomplished by two chromatography techniques using Sephacryl™ S-100 and phenyl HP columns. The neurotoxin was recovered with an overall yield of 21.5% and the purification factor increased to 216.7 fold. In addition, a mouse bioassay determined the purified neurotoxin complex possessed a specific toxicity (LD50) of 4.095 ng/kg

Intra-annual carbon fluxes and resource use efficiency of subtropical urban forests: insights from Chongming Island ecological observatory

Understanding the carbon budget within cities is crucial in the context of carbon peaking and carbon neutrality. This study investigates the carbon source-sink dynamics of urban forest ecosystems using carbon flux observations from the Chongming Island Ecological Observatory in Shanghai. The study aims to reveal the intra-annual variations of carbon fluxes and explore the changes in resource use efficiency of urban forest ecosystems within the framework of the big-leaf model. The results reveal distinct patterns in temperature (Tair), relative humidity (RH), radiation, and vapor pressure deficit (VPD). Diurnal cycles of net ecosystem exchange (NEE), gross primary production (GPP), and ecosystem respiration (Reco) exhibit seasonal variations, with higher amplitudes observed from April to September. The observed forest ecosystem acts as a moderate carbon sink (318.47 gC m−2 year−1), with the highest carbon uptake occurring in May and the highest carbon emission in February. During the growing season, the total carbon sink was 225.37 gC m−2, composed of GPP 1337.01 gC m−2 and Reco 1111.64 gC m−2. Water-use efficiency (WUE) and light-use efficiency (LUE) exhibit seasonal variations, while carbon-use efficiency (CUE) declines after May. These findings contribute to our understanding of urban forest carbon dynamics and their potential role in carbon management strategies

How to coadd images: II. Anti-aliasing and PSF deconvolution

We have developed a novel method for co-adding multiple under-sampled images that combines the iteratively reweighted least squares and divide-and-conquer algorithms. Our approach not only allows for the anti-aliasing of the images but also enables PSF deconvolution, resulting in enhanced restoration of extended sources, the highest PSNR, and reduced ringing artefacts. To test our method, we conducted numerical simulations that replicated observation runs of the CSST/VST telescope and compared our results to those obtained using previous algorithms. The simulation showed that our method outperforms previous approaches in several ways, such as restoring the profile of extended sources and minimizing ringing artefacts. Additionally, because our method relies on the inherent advantages of least squares fitting, it is more versatile and does not depend on the local uniformity hypothesis for the PSF. However, the new method consumes much more computation than the other approaches.Comment: 16 pages, 5 figures, 2 tables, accepted for publishing on RA

Quorum-quenching enzyme Est816 assisted antibiotics against periodontitis induced by Aggregatibacter actinomycetemcomitans in rats

IntroductionQuorum-quenching enzyme Est816 hydrolyzes the lactone rings of N-acyl homoserine lactones, effectively blocking the biofilm formation and development of Gram-negative bacteria. However, its applications in the oral field is limited. This study aimed to evaluate the efficacy of enzyme Est816 in combination with antibiotics against periodontitis induced by Aggregatibacter actinomycetemcomitans in vitro and in vivo.MethodsThe antimicrobial efficacy of enzyme Est816 in combination with minocycline, metronidazole, and amoxicillin was determined using the minimum inhibitory concentration test. The anti-biofilm effect of enzyme Est816 was assessed using scanning electron microscopy, live/dead bacterial staining, crystal violet staining, and real-time quantitative PCR. Biocompatibility of enzyme Est816 was assessed in human gingival fibroblasts (HGF) by staining. A rat model of periodontitis was established to evaluate the effect of enzyme Est816 combined with minocycline using micro-computed tomography and histological staining.ResultsCompared to minocycline, metronidazole, and amoxicillin treatment alone, simultaneous treatment with enzyme Est816 increased the sensitivity of biofilm bacteria to antibiotics. Enzyme Est816 with minocycline exhibited the highest rate of biofilm clearance and high biocompatibility. Moreover, the combination of enzyme Est816 with antibiotics improved the antibiofilm effects of the antibiotics synergistically, reducing the expression of the virulence factor leukotoxin gene (ltxA) and fimbria-associated gene (rcpA). Likewise, the combination of enzyme Est816 with minocycline exhibited a remarkable inhibitory effect on bone resorption and inflammation damage in a rat model of periodontitis.DiscussionThe combination of enzyme Est816 with antibiotics represents a prospective anti-biofilm strategy with the potential to treat periodontitis

Innovations in teaching during the COVID-19 pandemic: comparisons of the impacts of different teaching approaches in psychiatric nursing on undergraduate nursing students

Abstract Background Psychiatric nursing education was significantly impacted during the COVID-19 pandemic, and innovative teaching can be challenging. This study aims to compare the effectiveness of four approaches to psychiatric nursing education in the context of the pandemic. Methods A quasi-experimental design was adopted. Students were subjected to different teaching designs: face-to-face teaching (Class A in 2021), blended teaching with flipped classroom using roleplay (Class B in 2021), live broadcast teaching (Class A in 2022), and online blended teaching with flipped classroom using case studies (Class B in 2022). Multivariable logistic regression was used to analyse the outcomes in terms of academic performance and course workload. Results The number of valid data points was 270. The results indicated that compared with Class A in 2021, the two classes in 2022 achieved significantly higher academic performance scores, and Class B in 2021 exhibited a significantly lower workload. Compared with Class A in 2022, Class B in 2021 exhibited a significantly lower workload. Compared with Class B in 2022, Class B in 2021 exhibited a significantly lower workload and achieved lower academic performance scores. Conclusion This study demonstrated that innovative teaching designs for psychiatric nursing offer advantages with regard to either facilitating academic performance or optimizing learners’ task loads. Furthermore, blended learning is a promising teaching approach in the context of the COVID-19 pandemic. Future teaching initiatives could adopt student-centred constructive learning designs and ensure feasible teaching

Microbial tolerance engineering for boosting lactic acid production from lignocellulose

Abstract Lignocellulosic biomass is an attractive non-food feedstock for lactic acid production via microbial conversion due to its abundance and low-price, which can alleviate the conflict with food supplies. However, a variety of inhibitors derived from the biomass pretreatment processes repress microbial growth, decrease feedstock conversion efficiency and increase lactic acid production costs. Microbial tolerance engineering strategies accelerate the conversion of carbohydrates by improving microbial tolerance to toxic inhibitors using pretreated lignocellulose hydrolysate as a feedstock. This review presents the recent significant progress in microbial tolerance engineering to develop robust microbial cell factories with inhibitor tolerance and their application for cellulosic lactic acid production. Moreover, microbial tolerance engineering crosslinking other efficient breeding tools and novel approaches are also deeply discussed, aiming to providing a practical guide for economically viable production of cellulosic lactic acid

A non-enzymatic photoelectrochemical glucose sensor based on BiVO4 electrode under visible light

A non-enzymatic photoelectrochemical (PEC) glucose sensor based on nanoporous bismuth vanadate (BiVO 4 ) electrode is fabricated on fluorine doped tin oxide by electrochemical deposition. The photogenerated holes of BiVO 4 show a strong oxidizing ability, with adsorption of glucose on the surface of BiVO 4 , agreeing well with the classical Langmuir adsorption model. Under visible light irradiation, the glucose molecules adsorbed on the BiVO 4 electrode surface can be oxidized by the photogenerated holes, which results in increased photocurrent. The fabricated BiVO 4 non-enzymatic photoelectrochemical sensor shows outstanding catalytic activity, favourable selectivity, good reproducibility, and long-term stability for glucose detection under optimized conditions. The linear range was 0-5 mM (correlation coefficient, R = 0.997) with a detection limit of 0.13 μmol L −1 (signal-to-noise = 3). In addition, the proposed PEC sensor was successfully applied to detect glucose in human serum samples. Our work provides a new strategy for the non-enzymatic detection of glucose

Establishment of optimal regulatory network of colorectal cancer based on p42.3 protein

Objective: to establish regulatory network of colorectal cancer involving p42.3 protein and to provide theoretical evidence for deep functional exploration of p42.3 protein in the onset and development of colorectal cancer. Methods: with protein similarity algorithm, reference protein set of p42.3 cell apoptosis was built according to structural features of p42.3. GO and KEGG databases were used to establish regulatory network of tumor cell apoptosis involving p42.3; meanwhile, the largest possible working pathway that involves p42.3 protein was screened out based on Bayesian network theory. Besides, GO and KEGG were used to build regulatory network on early diagnosis gene markers for colorectal cancer including WWOX, K-ras, COX-2, p53, APC, DCC and PTEN, at the same time, a regulatory network of colorectal cancer cell apoptosis which involves p42.3 was established. Results: cell apoptotic regulatory network that p42.3 participates in primarily consists of Bcl-2 family genes and the largest possible pathway is p42.3 → FKBP → Bcl-2 centered as FKBP protein. Combined with colorectal cancer regulatory network that involves early diagnosis gene markers, it can be predicted that p42.3 is most likely to regulate the colorectal cancer cell apoptosis through FKBP → Bcl-2 → Bax → caspase-9 → caspase-3 pathway. Conclusion: the colorectal cancer apoptosis network based on p42.3 established in the study provides theoretical evidence for deep exploration of p42.3 regulatory mechanism and molecular targeting treatment of colorectal cancer

Sarm1/Myd88-5 Regulates Neuronal Intrinsic Immune Response to Traumatic Axonal Injuries

Summary: Traumatic injuries can trigger inflammatory reactions, leading to profound neuropathological consequences. However, the immune capacity of neurons, distinct from that of immune cells or glial cells, in response to traumatic insults remains to be fully characterized. In this study, we demonstrate that neurons can detect, cell autonomously, distant axonal damage, resulting in rapid production of a specific collection of cytokines and chemokines. This neuronal immune response appears spatially and temporally separated from injury-induced axon degeneration. We then identify through the genetic screen that this immune response is regulated by TIR-domain adaptor Sarm1/Myd88-5. We further show that Sarm1 functions through the downstream Jnk-c-Jun signal, and blockage of this Sarm1-Jnk-c-Jun pathway effectively abolishes the recruitment of immune cells to injury-afflicted neural tissues. We therefore uncover the key function of the Sarm1 signaling pathway, independent of its known role in axon degeneration, in the neuronal intrinsic immune response to traumatic axonal injuries. : Wang et al. report that neurons possess an intrinsic immune capacity in response to traumatic axonal injuries, which is spatially and temporally separated from injury-induced axon degeneration. This neuronal immune response is regulated by TIR-domain adaptor protein Sarm1/Myd88-5 and its downstream Jnk-c-Jun signal. Keywords: neuronal intrinsic immune response, traumatic injuries, neuroinflammation, Sarm