Bacterial biofilms are complex surface attached communities of bacteria held together by self-produced polymer matrixs mainly composed of polysaccharides, secreted proteins, and extracellular DNAs. ...Bacterial biofilm formation is a complex process and can be described in five main phases: (i) reversible attachment phase, where bacteria non-specifically attach to surfaces; (ii) irreversible attachment phase, which involves interaction between bacterial cells and a surface using bacterial adhesins such as fimbriae and lipopolysaccharide (LPS); (iii) production of extracellular polymeric substances (EPS) by the resident bacterial cells; (iv) biofilm maturation phase, in which bacterial cells synthesize and release signaling molecules to sense the presence of each other, conducing to the formation of microcolony and maturation of biofilms; and (v) dispersal/detachment phase, where the bacterial cells depart biofilms and comeback to independent planktonic lifestyle. Biofilm formation is detrimental in healthcare, drinking water distribution systems, food, and marine industries, etc. As a result, current studies have been focused toward control and prevention of biofilms. In an effort to get rid of harmful biofilms, various techniques and approaches have been employed that interfere with bacterial attachment, bacterial communication systems (quorum sensing, QS), and biofilm matrixs. Biofilms, however, also offer beneficial roles in a variety of fields including applications in plant protection, bioremediation, wastewater treatment, and corrosion inhibition amongst others. Development of beneficial biofilms can be promoted through manipulation of adhesion surfaces, QS and environmental conditions. This review describes the events involved in bacterial biofilm formation, lists the negative and positive aspects associated with bacterial biofilms, elaborates the main strategies currently used to regulate establishment of harmful bacterial biofilms as well as certain strategies employed to encourage formation of beneficial bacterial biofilms, and highlights the future perspectives of bacterial biofilms.
(Bt) is a widely used microbial pesticide. However, its duration of effectiveness is greatly shortened due to the irradiation of ultraviolet rays, which seriously hinders the application of Bt ...preparations. Therefore, it is of great importance to study the resistance mechanism of Bt to UV at the molecular level to improve the UV-resistance of Bt strains. In order to know the functional genes in the UV resistance, the genome of UV-induced mutant Bt LLP29-M19 was re-sequenced and compared with the original strain Bt LLP29. It was shown that there were 1318 SNPs, 31 InDels, and 206 SV between the mutant strain and the original strain Bt LLP29 after UV irradiation, which were then analyzed for gene annotation. Additionally, a mutated gene named
, a member of helicase superfamily II, was detected as an important candidate. Then,
was expressed and purified successfully. Through the result of the enzymatic activity
, yqhH was found to have ATP hydrolase and helicase activities. In order to further verify its function, the
gene was knocked out and complemented by homologous recombinant gene knockout technology. The survival rate of the knockout mutant strain Bt LLP29-Δ
was significantly lower than that of the original strain Bt LLP29 and the back-complemented strain Bt LLP29-Δ
-R after treated with UV. Meanwhile, the total helicase activity was not significantly different on whether Bt carried
or not. All of these greatly enrich important molecular mechanisms of Bt when it is in UV stress.
The intestinal tract of vertebrates is normally colonized with a remarkable number of commensal microorganisms that are collectively referred to as gut microbiota. Gut microbiota has been ...demonstrated to interact with immune cells and to modulate specific signaling pathways involving both innate and adaptive immune processes. Accumulated evidence suggests that the imbalance of Th17 and Treg cells is associated with the development of many diseases. Herein, we emphatically present recent findings to show how specific gut microbiota organisms and metabolites shape the balance of Th17 and Treg cells. We also discuss the therapeutic potential of fecal microbiota transplantation (FMT) in diseases caused by the imbalance of Th17 and Treg cells.
Chemical investigation of a strain Streptomyces sp. KIB-H1318 isolated from soil sample led to the discovery of three new phenoxazinone-related alkaloids 1-3, as well as two known analogs exfoliazone ...(4) and viridobrunnine A (5). Their structures were determined on the basis of extensive spectroscopic analysis. The antimicrobial activity and cytotoxicity of the isolates were assayed. Exfoliazone and viridobrunnine A exhibited minor antibacterial activity against Escherichia coli ATCC 8099, Bacillus subtilis ATCC 6633, and Staphylococcus aureus ATCC 6538. Compound 2 exhibited low cytotoxicity against two human cancer cell lines HeLa and SW480 with the IC
values of 36.8 and 37.8 μM, respectively.
Wheat straw (WS) is a potential biomass for production of monomeric sugars. However, the enzymatic hydrolysis ratio of cellulose in WS is relatively low due to the presence of lignin and ...hemicellulose. To enhance the enzymatic conversion of WS, we tested the impact of three different pretreatments, e.g. sulfuric acid (H
SO
), sodium hydroxide (NaOH), and hot water pretreatments to the enzymatic digestions. Among the three pretreatments, the highest cellulose conversion rate was obtained with the 4% NaOH pretreatment at 121 °C (87.2%). In addition, NaOH pretreatment was mainly effective in removing lignin, whereas the H
SO
pretreatment efficiently removed hemicellulose. To investigate results of pretreated process for enhancement of enzyme-hydolysis to the WS, we used scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy to analyze structural changes of raw and treated materials. The structural analysis indicated that after H
SO
and NaOH pretreatments, most of the amorphous cellulose and partial crystalline cellulose were hydrolyzed during enzymatic hydrolysis. The findings of the present study indicate that WS could be ideal materials for production of monomeric sugars with proper pretreatments and effective enzymatic base hydrolysis.
In this study, we investigated the Cr(VI) uptake mechanism of planktonic cells and biofilms of Bacillus subtilis (B. subtilis) ATCC-6633. Data showed that the effect of planktonic cells on the Cr(VI) ...uptake was quite different from that of biofilms. Planktonic cells had strong ability of Cr(VI) reduction, while biofilms possessed a great potential of Cr(III) immobilization. For planktonic cells, 100 mg/L Cr(VI) could be completely reduced. Both exopolymeric substances and cytoplasmic extracts contributed to high capacity of Cr(VI) reduction. After the reduction, noticeable Cr(III) precipitates were accumulated on bacterial surfaces, but 37.5% Cr(III) still remained in the supernatant. For biofilms, the biofilm debris became the main active ingredient of the Cr(VI) reduction. However, only 20 mg/L Cr(VI) could be reduced probably because of unavailability of reducing active sites during the biofilm formation. Further studies showed that biofilms had a better Cr(III) immobilization capacity than planktonic cells with 100% Cr(III) immobilized. Moreover, for the first time, we proposed a strategy combining the advantages of both planktonic cells and biofilms, and a successful Cr(VI) removal from typical Cr(VI)-containing plating wastewater was achieved through a 10-L pilot-scale experiment.
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•Different effects on Cr(VI) uptake between biofilms and planktonic cells was found.•A new strategy combining the advantages of planktonic cells and biofilms was proposed.•A successful Cr(VI) removal was achieved in a 10-L pilot-scale experiment.
Insect and mite pests are damaging stressors that are threatening the cultivation of tea plants, which result in enormous crop loss. Over the years, the effectiveness of synthetic pesticides has ...allowed for its prominent application as a control strategy. However, the adverse effects of synthetic pesticides in terms of pesticide residue, environmental contamination and insect pest resistance have necessitated the need for alternative strategies. Meanwhile, microbial pesticides have been applied to tackle the damaging activities of the insect and mite pests of tea plants, and their performances were scientifically adjudged appreciable and environmental friendly. Herein, entomopathogenic microbes that were effective against tea geometrid (
Ectropis obliqua
Prout), tea green leafhopper (
Empoasca onukii
Matsuda), paraguay tea ampul (
Gyropsylla spegazziniana
), tea mosquito bug (
Helopeltis theivora
Waterhouse) and red spider mite (
Oligonychus coffea
Nietner) have been reviewed. The current findings revealed that microbial pesticides were effective and showed promising performances against these pests. Overall, this review has provided the basic and integrative information on the integrated pest management (IPM) tool(s) that can be utilized towards successful control of the aforementioned insect and mite pests.
Graphic abstract
Background： Nowadays, social media tools such as short message service, Twitter, video, and web-based systems are more and more used in clinical follow-up, making clinical follow-up much more time- ...and cost-effective than ever before. However, as the most popular social media in China, little is known about the utility of smartphone WeChat application in follow-up. In this study, we aimed to investigate the feasibility and superiority of WeChat application in clinical follow-up. Methods： A total of 108 patients diagnosed with head and neck tumor were randomized to WeChat follow-up （WFU） group or telephone follow-up （TFU） group for 6-month follow-up. The follow-ups were delivered by WeChat or telephone at 2 weeks, 1, 2, 3, and 6 months to the patients after being discharged. The study measurements were time consumption for follow-up delivery, total economic cost, lost-to-follow-up rate, and overall satisfaction for the follow-up method. Results： Time consumption in WFU group for each patient （23.36 ± 6.16 min） was significantly shorter than that in TFU group （42.89 ± 7.15 min） （P 〈 0.001 ）; total economic cost in WFU group （RMB 90 Yuan） was much lower than that in TFU group （RMB 196 Yuan）. Lost-to-follow-up rate in the WFU group was 7.02% （4/57） compared with TFU group, 9.80% （5/51 ）, while no significance was observed （95% confidence interval CI： 0.176-2.740; P = 0.732）. The overall satisfaction rate in WFU group was 94.34% （50/53） compared with 80.43% （37/46） in TFU group （95% CI： 0.057-0.067; P = 0.034）. Conclusions： The smartphone WeChat application was found to be a viable option for follow-up in discharged patients with head and neck tumors. WFU was time-effective, cost-effective, and convenient in communication. This doctor-led follow-up model has the potential to establish a good physician-patient relationship by enhancing dynamic communications and providing individual health instructions.
Hepatocellular carcinoma (HCC) is a common liver cancer that accounts for 90% of cases. Doxorubicin exhibits a broad spectrum of antitumor activity and is one of the most active agents in HCC. WW ...domain‐containing protein 2 (WWP2) is highly expressed in HCC tissues and activates protein kinase B (AKT) signaling pathway to enhance tumor metastasis. However, the role of WWP2 in the glycolysis and antitumor effects of doxorubicin and the epigenetic alterations of WWP2 in HCC remain to be elucidated. The levels of WWP2 and N6‐methyladenosine methyltransferase‐like 3 (METTL3) in clinical samples and cells were investigated. WWP2 were silenced or overexpressed to study the role of WWP2 in regulating cell proliferation, colony formation, and glycolysis. RNA immunoprecipitation was performed to test m6A levels. Quantitative reverse‐transcription polymerase chain reaction (RT‐PCR) and Western blot were used to measure mRNA and protein, respectively. WWP2 silencing inhibits cell proliferation, colony formation, and glycolysis, while WWP2 overexpression has the inverse effects via the AKT signaling pathway. Silencing WWP2 enhances doxorubicin's antitumor effect, while WWP2 overexpression suppresses doxorubicin's antitumor effect. Data also support that METTL3 mediates WWP2 m6A modification, and m6A reader, IGF2BP2, binds to the methylated WWP2 to promote the stability of WWP2, leading to upregulation of WWP2. METTL3 mediates WWP2 m6A modification, which can be recognized and bound by IGF2BP2 to increase the stability of WWP2, leading to WWP2 overexpression which inhibits the antitumor effects of doxorubicin through METTL3/WWP2/AKT/glycolysis axis.
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