Bacterial extracellular vesicle: A non-negligible component in biofilm life cycle and challenges in biofilm treatments.

Bacterial biofilms, especially those formed by pathogens, have been increasingly impacting human health. Bacterial extracellular vesicle (bEV), a kind of spherical membranous structure released by bacteria, has not only been reported to be a component of the biofilm matrix but also plays a non-negligible role in the biofilm life cycle. Nevertheless, a comprehensive overview of the bEVs functions in biofilms remains elusive. In this review, we summarize the biogenesis and distinctive features characterizing bEVs, and consolidate the current literature on their functions and proposed mechanisms in the biofilm life cycle. Furthermore, we emphasize the formidable challenges associated with vesicle interference in biofilm treatments. The primary objective of this review is to raise awareness regarding the functions of bEVs in the biofilm life cycle and lay the groundwork for the development of novel therapeutic strategies to control or even eliminate bacterial biofilms.

The promotion of biofilm dispersion: a new strategy for eliminating foodborne pathogens in the food industry.

Food safety is a critical global concern due to its direct impact on human health and overall well-being. In the food processing environment, biofilm formation by foodborne pathogens poses a significant problem as it leads to persistent and high levels of food contamination, thereby compromising the quality and safety of food. Therefore, it is imperative to effectively remove biofilms from the food processing environment to ensure food safety. Unfortunately, conventional cleaning methods fall short of adequately removing biofilms, and they may even contribute to further contamination of both equipment and food. It is necessary to develop alternative approaches that can address this challenge in food industry. One promising strategy in tackling biofilm-related issues is biofilm dispersion, which represents the final step in biofilm development. Here, we discuss the biofilm dispersion mechanism of foodborne pathogens and elucidate how biofilm dispersion can be employed to control and mitigate biofilm-related problems. By shedding light on these aspects, we aim to provide valuable insights and solutions for effectively addressing biofilm contamination issues in food industry, thus enhancing food safety and ensuring the well-being of consumers.

DeflickerCycleGAN: learning to detect and remove flickers in a single image.

Eliminating the flickers in digital images captured by rolling shutter cameras is a fundamental and important task in computer vision applications. The flickering effect in a single image stems from the mechanism of asynchronous exposure of rolling shutters employed by cameras equipped with CMOS sensors. In an artificial lighting environment, the light intensity captured at different time intervals varies due to the fluctuation of the AC-powered grid, ultimately leading to the flickering artifact in the image. Up to date, there are few studies related to single image deflickering. Further, it is even more challenging to remove flickers without a priori information, e.g., camera parameters or paired images. To address these challenges, we propose an unsupervised framework termed DeflickerCycleGAN, which is trained on unpaired images for end-to-end single image deflickering. Besides the cycle-consistency loss to maintain the similarity of image contents, we meticulously design another two novel loss functions, i.e., gradient loss and flicker loss, to reduce the risk of edge blurring and color distortion. Moreover, we provide a strategy to determine whether an image contains flickers or not without extra training, which leverages an ensemble methodology based on the output of two previously trained markovian discriminators. Extensive experiments on both synthetic and real datasets show that our proposed DeflickerCycleGAN not only achieves excellent performance on flicker removal in a single image but also shows high accuracy and competitive generalization ability on flicker detection, compared to that of a well-trained classifier based on ResNet50.

A Flagella Hook Coding Gene flgE Positively Affects Biofilm Formation and Cereulide Production in Emetic Bacillus cereus.

Bacillus cereus, an important foodborne pathogen, poses a risk to food safety and quality. Robust biofilm formation ability is one of the key properties that is responsible for the food contamination and food poisoning caused by B. cereus, especially the emetic strains. To investigate the mechanism of biofilm formation in emetic B. cereus strains, we screened for the mutants that fail to form biofilms by using random mutagenesis toward B. cereus 892-1, an emetic strain with strong biofilm formation ability. When knocking out flgE, a flagellar hook encoding gene, the mutant showed disappearance of flagellar structure and swimming ability. Further analysis revealed that both pellicle and ring presented defects in the null mutant compared with the wild-type and complementary strains. Compared with the flagellar paralytic strains Δ motA and Δ motB, the inhibition of biofilm formation by Δ flgE is not only caused by the inhibition of motility. Interestingly, Δ flgE also decreased the synthesis of cereulide. To our knowledge, this is the first report showing that a flagellar component can both affect the biofilm formation and cereulide production in emetic B. cereus, which can be used as the target to control the biohazard of emetic B. cereus.

Novel Selenium Peptides Obtained from Selenium-Enriched Cordyceps militaris Alleviate Neuroinflammation and Gut Microbiota Dysbacteriosis in LPS-Injured Mice.

Increasing attention focuses on the relationship between neuroinflammation and Alzheimer's disease (AD). The reports on the microbiota-gut-brain axis reveal that the regulation by gut microbiota is an effective way to intervene in neuroinflammation-related AD. In this study, two novel selenium peptides (Se-Ps), VPRKL(Se)M (Se-P1) and RYNA(Se)MNDYT (Se-P2), with neuroprotection effects were obtained from Se-enriched Cordyceps militaris. Se-P1 and Se-P2 pre-protection led to a 30 and 33% increase in the PC-12 cell viability compared to the damage group, respectively. Moreover, Se-Ps exhibited a significant pre-protection against LPS-induced inflammatory and oxidative stress in the colon and brain by inhibiting the production of pro-inflammatory mediators (p < 0.05) and malondialdehyde, as well as promoting anti-inflammatory cytokine level and antioxidant enzyme activity (p < 0.05), which may alleviate the cognitive impairment in LPS-injured mice (p < 0.05). Se-Ps not only repaired the intestinal mucosa damage of LPS-injured mice but also had a positive effect on gut microbiota dysbacteriosis by increasing the abundance of Lactobacillus and Alistipes and decreasing the abundance of Akkermansia and Bacteroides. Collectively, the antioxidant, anti-inflammatory, and regulating properties on gut microflora of Se-Ps contribute to their neuroprotection, supporting that Se-Ps could be a promising dietary supplement in the prevention and/or treatment of AD.