Role of Hfq in glucose utilization, biofilm formation and quorum sensing system in Bacillus subtilis.

Hfq is an RNA-binding protein, its main function is to participate in post-transcriptional regulation of bacteria and regulate small regulatory RNA (sRNA) and messenger RNA (mRNA) stability, but the Hfq function of Bacillus subtilis (B. subtilis) has not been fully explained. In this study, we used the strains of B. subtilis168 (BS168), BS168Δhfq and BS168Δhfq-C to explore the effects of Hfq on the glucose utilization, biofilm formation and quorum sensing (QS) system of B. subtilis. The results showed that the knockout of hfq resulted in growth defects when bacteria were cultured in the Luria-Bertani (LB) medium, but we did not observe the same effects in Nitrogen medium (NM) and Inorganic Salt-free medium (ISM). We further found that the growth of strains under different glucose concentrations was also different, which was related to the expression of CcpA. Interestingly, the hfq mutant showed increased resistance to a high-glucose environment. Furthermore, the biofilm and extracellular poly saccharides (EPS) formation of BS168Δhfq decreased significantly. At the same time, changes were observed in the morphology of the biofilm, such as larger intercellular space of the biofilm and thinner edge. The qRT-PCR results confirmed that the hfq knockout caused significant up-regulation or down-regulation of gene expression in QS system, and down-regulated genes were involved in the positive regulation of biofilm formation. Taken together, we demonstrated that Hfq plays a vital role in glucose utilization, biofilm formation and QS of B. subtilis, which provides a new perspective for subsequent related research.

RNA-binding protein Hfq plays a vital role in cellulose decomposition throughout affecting cellulase gene expression.

OBJECTIVE: To study the function of the RNA-binding protein Hfq in Bacillus subtilis cellulose decomposition. RESULTS: In the medium with sodium carboxymethylcellulose (Na-CMC) as the sole carbon source, the knockout of Hfq resulted in a 38.0% ± 2.1% and 76.6% ± 7.1% decrease in cellulose hydrolysis ability and cellulase activity, respectively. The results of real-time quantitative PCR revealed that several cellulase genes (eglS, bglA, and bglC) were significantly downregulated in the Hfq knockout strain. The isogenic Δhfq complemented strain recovered the cellulose hydrolysis ability, cellulase activity, and expression level of cellulase genes. In addition, the survival of Hfq mutant in stationary phase was significantly affected. CONCLUSION: RNA-binding protein Hfq is involved in the regulation of cellulose hydrolysis ability, cellulase activity, cellulase gene expression, and stationary phase survival.

A comprehensive evaluation of the temporal and spatial fouling characteristics of RO membranes in a full-scale seawater desalination plant.

The fouling of seawater reverse osmosis (SWRO) membranes remains a persistent challenge in desalination. Previous research has focused mainly on fouling separately; however, organic, inorganic, and biofouling can coexist and influence each other. Hence, in-depth study of the spatiotemporal changes in actual combined fouling in full-scale seawater desalination will provide more effective information for fouling investigation and control. In this study, we monitored (i) the operational performance of a full-scale desalination plant for 7 years and (ii) the development and characterization of membrane and spacer fouling at different locations of spiral-wound membrane modules sampled after 2.5-, 3.5-, and 7-year operation. The findings showed that (i) operational performance indicators declined with time (normalized flux 40 % reduction, salt rejection 2 % in 7 years), with a limited effect of the 20-day cleaning frequency, (ii) fouling accumulation in the membrane module mainly occurred at the feed side of the lead module and the microbial community in these area exhibited the highest diversity, (iii) the dominant microbial OTUs belonged mainly to Proteobacteria (43-70 %), followed by Bacteroidetes (10-11 %), (iv) Phylogenetic molecular ecological networks and Spearman correlation analysis revealed that Chloroflexi (Anaerolineae) and Planctomycetes were keystone species in maintaining the community structure and biofilm maturation and significantly impacted the foulant content on the SWRO membrane, even with low abundance, and that (v) fouling accumulation was composed of polysaccharides, soluble microbial products, marine humic acid-like substances, and inorganic Ca/Fe/Mg/Si dominate the fouling layer of both the membrane and spacer. Overall, variation partitioning analysis quantitatively describes the increasing contribution of biofouling over time. Ultimately, the organic‒inorganic-biofouling interaction (70 %) significantly contributed to the overall fouling of the membrane after 7 years of operation. These results can be used to develop more targeted fouling control strategies to optimize SWRO desalination plant design and operation.

A denoising method based on cyclegan with attention mechanisms for improving the hidden distress features of pavement.

Ground Penetrating Radar (GPR) is one of the most used devices for road structural damages detection. However, due to the different roadbed conditions and various disturbances in the nearby environment during detection, there are great difficulties in interpreting detection images, which also hinders automatic detection based on deep learning. In this work, we design a GPR image denoising method based on Cyclegan. We select the most suitable generator and add different attention mechanisms. After denoising the natural GPR road detection image, using the Yolo (You Only Look Once) to test the accuracy of the original image and the denoised image after adding different attention mechanisms. The detection accuracy is improved by 30%. The results of the detection network and the evaluation of the denoised images by GPR image interpreters indicate that the method has the following advantages: lower requirements for training data sets, a wide range of data sources, low cost, good denoising effect, and automatic detection of GPR images. It is of great help to the automatic detection of GPR images.

Prevalence and Molecular Characterization of Cryptosporidium serpentis in Captive Snakes in China.

Cryptosporidium species are the causative agent of cryptosporidiosis and common intracellular parasites that can infect a wide range of vertebrates, including snakes. In previous studies, Cryptosporidium species infections have been reported in snakes in Asia, Europe, and North America. However, limited information is available about the prevalence and molecular characterization of Cryptosporidium in captive snakes in China. Fecal specimens from 609 captive snakes were collected from Beijing (n = 227), Chengdu (n = 12), Dazhou (n = 359), and Ziyang (n = 11). The partial small-subunit (SSU) rRNA gene was amplified by nested polymerase chain reaction to determine the prevalence of Cryptosporidium, and a phylogenetic tree was constructed to assess evolutionary relationships and genetic characteristics. The overall prevalence of Cryptosporidium was 1.97% (12/609). BLAST and phylogenetic analysis of the small subunit ribosomal RNA (SSU rRNA) gene showed that the parasites belonged to Cryptosporidium serpentis. To the best of our knowledge, this is the first study to report the prevalence of Cryptosporidium in snakes of southwestern and northern China and provides preliminary data for the control and prevention of cryptosporidiosis in the investigated areas.