Paeonol Attenuates Quorum-Sensing Regulated Virulence and Biofilm Formation in Pseudomonas aeruginosa

With the prevalence of multidrug-resistant bacteria and clinical -acquired pathogenic infections, the development of quorum-sensing (QS) interfering agents is one of the most potential strategies to combat bacterial infections and antibiotic resistance. Chinese herbal medicines constitute a valuable bank of resources for the identification of QS inhibitors. Accordingly, in this research, some compounds were tested for QS inhibition using indicator strains. Paeonol is a phenolic compound, which can effectively reduce the production of violacein without affecting its growth in Chromobacterium violaceum ATCC 12472, indicating its excellent anti-QS activity. This study assessed the anti-biofilm activity of paeonol against Gram-negative pathogens and investigated the effect of paeonol on QS-regulated virulence factors in Pseudomonas aeruginosa. A Caenorhabditis elegans infection model was used to explore the anti-infection ability of paeonol in vivo. Paeonol exhibited an effective anti-biofilm activity against Gram-negative bacteria. The ability of paeonol to interfere with the AHL-mediated quorum sensing systems of P. aeruginosa was determined, found that it could attenuate biofilm formation, and synthesis of pyocyanin, protease, elastase, motility, and AHL signaling molecule in a concentration- and time-dependent manner. Moreover, paeonol could significantly downregulate the transcription level of the QS-related genes of P. aeruginosa including lasI/R, rhlI/R, pqs/mvfR, as well as mediated its virulence factors, lasA, lasB, rhlA, rhlC, phzA, phzM, phzH, and phzS. In vivo studies revealed that paeonol could reduce the pathogenicity of P. aeruginosa and enhance the survival rate of C. elegans, showing a moderate protective effect on C. elegans. Collectively, these findings suggest that paeonol attenuates bacterial virulence and infection of P. aeruginosa and that further research elucidating the anti-QS mechanism of this compound in vivo is warranted.

PI3K Plays an Essential Role in Planarian Regeneration and Tissue Maintenance

Phosphatidylinositol 3-kinase (PI3K) signaling plays a central role in various biological processes, and its abnormality leads to a broad spectrum of human diseases, such as cancer, fibrosis, and immunological disorders. However, the mechanisms by which PI3K signaling regulates the behavior of stem cells during regeneration are poorly understood. Planarian flatworms possess abundant adult stem cells (called neoblasts) allowing them to develop remarkable regenerative capabilities, thus the animals represent an ideal model for studying stem cells and regenerative medicine in vivo. In this study, the spatiotemporal expression pattern of Djpi3k, a PI3K ortholog in the planarian Dugesia japonica, was investigated and suggests its potential role in wound response and tissue regeneration. A loss-of-function study was conducted using small molecules and RNA interference technique, providing evidence that PI3K signaling is required for blastema regrowth and cilia maintenance during planarian regeneration and homeostasis. Interestingly, the mitotic and apoptotic responses to amputation are substantially abated in PI3K inhibitor-treated regenerating animals, while knockdown of Djpi3k alleviates the mitotic response and postpones the peak of apoptotic cell death, which may contribute to the varying degrees of regenerative defects induced by the pharmacological and genetic approaches. These observations reveal novel roles for PI3K signaling in the regulation of the cellular responses to amputation during planarian regeneration and provide insights for investigating the disease-related genes in the regeneration-competent organism in vivo.

The development of Nanosota-1 as anti-SARS-CoV-2 nanobody drug candidates

Combating the COVID-19 pandemic requires potent and low-cost therapeutics. We identified a series of single-domain antibodies (i.e., nanobody), Nanosota-1, from a camelid nanobody phage display library. Structural data showed that Nanosota-1 bound to the oft-hidden receptor-binding domain (RBD) of SARS-CoV-2 spike protein, blocking viral receptor angiotensin-converting enzyme 2 (ACE2). The lead drug candidate possessing an Fc tag (Nanosota-1C-Fc) bound to SARS-CoV-2 RBD ~3000 times more tightly than ACE2 did and inhibited SARS-CoV-2 pseudovirus ~160 times more efficiently than ACE2 did. Administered at a single dose, Nanosota-1C-Fc demonstrated preventive and therapeutic efficacy against live SARS-CoV-2 infection in both hamster and mouse models. Unlike conventional antibodies, Nanosota-1C-Fc was produced at high yields in bacteria and had exceptional thermostability. Pharmacokinetic analysis of Nanosota-1C-Fc documented an excellent in vivo stability and a high tissue bioavailability. As effective and inexpensive drug candidates, Nanosota-1 may contribute to the battle against COVID-19.

The antiviral activity of kaempferol against pseudorabies virus in mice

Background

Pseudorabies virus (PRV), a member of the Alphaherpesviruses, is one of the most important pathogens that harm the global pig industry. Accumulated evidence indicated that PRV could infect humans under certain circumstances, inducing severe clinical symptoms such as acute human encephalitis. Currently, there are no antiviral drugs to treat PRV infections, and vaccines available only for swine could not provide full protection. Thus, new control measures are urgently needed.

Results

In the present study, kaempferol exhibited anti-PRV activity in mice through improving survival rate by 22.22 %, which was higher than acyclovir (Positive control) with the survival rate of 16.67 % at 6 days post infection (dpi); meanwhile, the survival rate was 0 % at 6 dpi in the infected-untreated group. Kaempferol could inhibit the virus replication in the brain, lung, kidney, heart and spleen, especially the viral gene copies were reduced by over 700-fold in the brain, which was further confirmed by immunohistochemical examination. The pathogenic changes induced by PRV infection in these organs were also alleviated. The transcription of the only immediate-early gene IE180 in the brain was significantly inhibited by kaempferol, leading to the decreased transcriptional levels of the early genes (EPO and TK). The expression of latency-associated transcript (LAT) was also inhibited in the brain, which suggested that kaempferol could inhibit PRV latency. Kaempferol-treatment could induce higher levels of IL-1β, IL-4, IL-6, TNF-α and IFN-γ in the serum at 3 dpi which were then declined to normal levels at 5 dpi.

Conclusions

These results suggested that kaempferol was expected to be a new alternative control measure for PRV infection.

[Two-Stage Denitrification Process Performance with Solid Slow-Release Carbon Source]

During wastewater treatment using a traditional biological denitrification process, the excessive concentration of nitrate nitrogen (NO₃^--N) in the effluent is the primary cause of excessive total nitrogen (TN) generation. By using an external carbon source to increase the carbon to nitrogen ratio (C/N), the denitrification process can be strengthened, which effectively addresses this problem. Using an integrated denitrification reactor developed based on the two-stage denitrification process principle with the addition of polybutylene succinate (PBS) in the second stage, the denitrification process was analyzed using a scanning electron microscope before and after characterization of PBS materials. Moreover, amplicon sequencing was used for in-depth exploration of changes in the microbial community structure in the second denitrification pool before and after the addition of PBS. The data of a continuous 120-day experiment showed that the COD removal rate dropped from 95.7% to 90.8%, the TN removal rate increased from 51.8% to 80%, the relative abundance of Proteobacteria phylum rose from 36.1% to 46.1%, and the relative abundance of Thermomonas rose from 6.47% to 13.48%. The results show that after the addition of PBS, PBS can not only provide carbon source for denitrification, but its surface can also serve as a carrier for microbial growth and attachment, play a good role in filming, and increase the abundance of denitrifying bacteria and strengthen denitrification. During the nitrification process, denitrification performance was significantly enhanced, effectively improving the TN removal rate of the system.

Integrated management to reduce fistula-related long-term complications and improve the quality of life after arteriovenous fistula surgery: A retrospective cohort study

AIM

Proper arteriovenous fistula (AVF) management is crucial to avoid AVF complications and prolong its useful life for maintenance haemodialysis (MHD).

DESIGN

Retrospective cohort study.

METHODS

Patients on MHD who underwent AVF surgery at the Wuhan Third Hospital between January 2018 and July 2018.

RESULTS

A total of 144 patients were included, with 56 in the integrated group and 88 in the routine group. There were no differences between the two groups in terms of sex (p = .61), age (p = .62) and type of primary kidney disease (p > .99). At 1 year, the integrated group had significantly fewer fistula-related complications than the routine group (3.6% versus. 23.9%, p < .001). AVF functional scores were lower in the integrated group compared with the routine group (0.1 ± 0.5 versus. 0.8 ± 0.8, p < .001). The pain scores were lower in the integrated group than in the routine group (1.2 ± 0.4 versus. 1.8 ± 0.9, p < .001).

Antimicrobial Resistance Trends in Urine Escherichia coli Isolates From Adult and Adolescent Females in the United States From 2011-2019: Rising ESBL Strains and Impact on Patient Management

Background

Uncomplicated urinary tract infection (uUTI) is predominantly caused by Escherichia coli, which has increasing antimicrobial resistance (AMR) at the United States (US)-community level. As uUTI is often treated empirically, assessing AMR is challenging, and there are limited contemporary data characterizing period prevalence in the US.

Methods

This was a retrospective study of AMR using Becton, Dickinson and Company Insights Research Database (Franklin Lakes, New Jersey, US) data collected 2011–2019. Thirty-day, nonduplicate Escherichia coli urine isolates from US female outpatients (aged ≥12 years) were included. Isolates were evaluated for nonsusceptibility (intermediate/resistant) to trimethoprim-sulfamethoxazole, fluoroquinolones, or nitrofurantoin, and assessed for extended-spectrum β-lactamase production (ESBL+) and for ≥2 or ≥3 drug-resistance phenotypes. Generalized estimating equations were used to model AMR trends over time and by US census region.

Results

Among 1 513 882 E. coli isolates, the overall prevalence of isolates nonsusceptible to trimethoprim-sulfamethoxazole, fluoroquinolones, and nitrofurantoin was 25.4%, 21.1%, and 3.8%, respectively. Among the isolates, 6.4% were ESBL+, 14.4% had ≥2 drug-resistance phenotypes, and 3.8% had ≥3. Modeling demonstrated a relative average yearly increase of 7.7% (95% confidence interval [CI], 7.2–8.2%) for ESBL+ isolates and 2.7% (95% CI, 2.2–3.2%) for ≥3 drug-phenotypes (both P < .0001). Modeling also demonstrated significant variation in AMR prevalence between US census regions (P < .001).

Conclusions

Period prevalence of AMR among US outpatient urine-isolated E. coli was high, and for multidrug-resistance phenotypes increased during the study period with significant variation between census regions. Knowledge of regional AMR rates helps inform empiric treatment of community-onset uUTI and highlights the AMR burden to physicians.

Molecular Doping Directed by a Neutral Radical

Molecular doping makes possible tunable electronic properties of organic semiconductors, yet a lack of control of the doping process narrows its scope for advancing organic electronics. Here, we demonstrate that the molecular doping process can be improved by introducing a neutral radical molecule, namely nitroxyl radical (2,2,6,6-teramethylpiperidin-i-yl) oxyl (TEMPO). Fullerene derivatives are used as the host and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazoles (DMBI-H) as the n-type dopant. TEMPO can abstract a hydrogen atom from DMBI-H and transform the latter into a much stronger reducing agent DMBI•, which efficiently dopes the fullerene derivative to yield an electrical conductivity of 4.4 S cm-1. However, without TEMPO, the fullerene derivative is only weakly doped likely by a hydride transfer following by an inefficient electron transfer. This work unambiguously identifies the doping pathway in fullerene derivative/DMBI-H systems in the presence of TEMPO as the transfer of a hydrogen atom accompanied by electron transfer. In the absence of TEMPO, the doping process inevitably leads to the formation of less symmetrical hydrogenated fullerene derivative anions or radicals, which adversely affect the molecular packing. By adding TEMPO we can exclude the formation of such species and, thus, improve charge transport. In addition, a lower temperature is sufficient to meet an efficient doping process in the presence of TEMPO. Thereby, we provide an extra control of the doping process, enabling enhanced thermoelectric performance at a low processing temperature.

Effect of Inadequate Empiric Antibacterial Therapy on Hospital Outcomes in SARS-CoV-2-Positive and -Negative US Patients With a Positive Bacterial Culture: A Multicenter Evaluation From March to November 2020

Background

Increased utilization of antimicrobial therapy has been observed during the coronavirus disease 2019 pandemic. We evaluated hospital outcomes based on the adequacy of antibacterial therapy for bacterial pathogens in US patients.

Methods

This multicenter retrospective study included patients with ≥24 hours of inpatient admission, ≥24 hours of antibiotic therapy, and discharge/death from March to November 2020 at 201 US hospitals in the BD Insights Research Database. Included patients had a test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and a positive bacterial culture (gram-positive or gram-negative). We used generalized linear mixed models to evaluate the impact of inadequate empiric therapy (IET), defined as therapy not active against the identified bacteria or no antimicrobial therapy in the 48 hours following culture, on in-hospital mortality and hospital and intensive care unit length of stay (LOS).

Results

Of 438 888 SARS-CoV-2-tested patients, 39 203 (8.9%) had positive bacterial cultures. Among patients with positive cultures, 9.4% were SARS-CoV-2 positive, 74.4% had a gram-negative pathogen, 25.6% had a gram-positive pathogen, and 44.1% received IET for the bacterial infection. The odds of mortality were 21% higher for IET (odds ratio [OR], 1.21; 95% CI, 1.10–1.33; P < .001) compared with adequate empiric therapy. IET was also associated with increased hospital LOS (LOS, 16.1 days; 95% CI, 15.5–16.7 days; vs LOS, 14.5 days; 95% CI, 13.9–15.1 days; P < .001). Both mortality and hospital LOS findings remained consistent for SARS-CoV-2-positive and -negative patients.

Conclusions

Bacterial pathogens continue to play an important role in hospital outcomes during the pandemic. Adequate and timely therapeutic management may help ensure better outcomes.

Identification of the amino acids residues involved in hemagglutinin-neuraminidase of Newcastle disease virus binding to sulfated Chuanmingshen violaceum polysaccharides

The antiviral mechanism of sulfated polysaccharides is supposed to prevent virus entry, which is mediated by the interactions of anionic charges on sulfated polysaccharides with positively charged domains of viral envelope glycoproteins, leading to shielding of the functional domain involved in virus attachment to cell surface receptors. But, few direct evidences were reported. In the previous study, we found that sulfated Chuanmingshen violaceum polysaccharides (sCVPS) possessed remarkable inhibitory effect against Newcastle disease virus (NDV) through inhibition of NDV attachment to host cells. Whether sCVPS bound to hemagglutinin-neuraminidase (HN) leading to inhibition of NDV attachment needs to be further clarified. The present study conducted site-directed mutagenesis of possible positively charged residues of HN, and found that mutants R197G, H199G, R363G, and R523G could significantly decrease the inhibitory effects of sCVPS on receptor binding ability through hemadsorption assay, especially R363G which suggested that binding to R363 is more effective to shield the sialic acid binding sites. Dual mutants (R363G/R197G, R363G/H199G and R363G/R523G) induced more decreased inhibitory effect of sCVPS than single mutants. The immunofluorescence study using FITC-labeled sCVPS found that the fluorescence intensity of mutants R363G and R363G/H199G were significantly decreased. The binding kinetics of sCVPS to HN measured by surface plasmon resonance indicated that sCVPS had a higher binding affinity for wild-type HN than mutants R363G and R363G/H199G. Plaque reduction study was performed using recombinant NDV with mutant HN_R363G and HN_R363G/H199G, which showed significantly decreased inhibitory effects of sCVPS against mutant NDV adsorption to BHK-21 cells. These results suggested that the residues R197, H199, R363, and R523 were the binding sites for sCVPS, especially R363 act as the main interaction site. The present study provided direct evidence for the theory that antiviral mechanism of sulfated polysaccharides attributed to anionic groups binding to the positively charged residues of viral proteins which led to the shielding of receptor binding sites.

EGCG-Mediated Potential Inhibition of Biofilm Development and Quorum Sensing in Pseudomonas aeruginosa

Pseudomonas aeruginosa (P. aeruginosa), one of the dangerous multidrug resistance pathogens, orchestrates virulence factors production through quorum sensing (QS). Since the exploration of QS inhibitors, targeting virulence to circumvent bacterial pathogenesis without causing significant growth inhibition is a promising approach to treat P. aeruginosa infections. The present study has evaluated the anti-QS and anti-infective activity of epigallocatechin-3-gallate (EGCG), a bioactive ingredient of the traditional green tea, against P. aeruginosa. EGCG showed significant inhibitory effects on the development of biofilm, protease, elastase activity, swimming, and swarming motility, which was positively related to the production of C4-AHL. The expression of QS-related and QS-regulated virulence factors genes was also evaluated. Quantitative PCR analysis showed that EGCG significantly reduced the expression of las, rhl, and PQS genes and was highly correlated with the alterations of C4-AHL production. In-vivo experiments demonstrated that EGCG treatment reduced P. aeruginosa pathogenicity in Caenorhabditis elegans (C. elegans). EGCG increased the survival of C. elegans by 23.25%, 30.04%, and 36.35% in a dose-dependent manner. The findings of this study strongly suggest that EGCG could be a potential candidate for QS inhibition as an anti-virulence compound against bacterial infection.

Endoscope-controlled maxillary sinus floor elevation: a review of the literature

A systematic review of the literature was conducted to assess the safety and efficacy of endoscope-assisted maxillary sinus elevation. PubMed, Embase, Web of Science, and the Cochrane database were searched for articles in English. Published studies involving patients who had undergone endoscope-assisted maxillary sinus floor augmentation were selected. The validity of the included articles was evaluated. After going through full texts, a total of 12 studies met the eligibility criteria and were included. It was concluded that endoscope-controlled maxillary sinus floor elevation was a viable and beneficial method, providing direct visualisation of the integrity of the mucosa and placing of bone graft material. The endoscope could be inserted into the maxillary sinus lumen, subantral space below the Schneiderian membrane, or through the alveolar crest. With the endoscope, perforations can be detected and managed precisely. However, high-quality clinical trials are still needed to validate the predictability and advantages of this surgical procedure.

Controlling n-Type Molecular Doping via Regiochemistry and Polarity of Pendant Groups on Low Band Gap Donor-Acceptor Copolymers

We demonstrate the impact of the type and position of pendant groups on the n-doping of low-band gap donor–acceptor (D–A) copolymers. Polar glycol ether groups simultaneously increase the electron affinities of D–A copolymers and improve the host/dopant miscibility compared to nonpolar alkyl groups, improving the doping efficiency by a factor of over 40. The bulk mobility of the doped films increases with the fraction of polar groups, leading to a best conductivity of 0.08 S cm^–1 and power factor (PF) of 0.24 μW m^–1 K^–2 in the doped copolymer with the polar pendant groups on both the D and A moieties. We used spatially resolved absorption spectroscopy to relate commensurate morphological changes to the dispersion of dopants and to the relative local doping efficiency, demonstrating a direct relationship between the morphology of the polymer phase, the solvation of the molecular dopant, and the electrical properties of doped films. Our work offers fundamental new insights into the influence of the physical properties of pendant chains on the molecular doping process, which should be generalizable to any molecularly doped polymer films.

Silencing of long non-coding RNA XIST represses gastric cancer progression through blocking NFκB pathway via inhibiting HNF4A-mediated transcription of EPHA1

Gastric cancer (GC) is a common cancer and a leading cause of cancer-related deaths worldwide. Recent studies have supported the important role of long non-coding RNAs (lncRNAs) in GC progression. This study identified functional significance of X inactive specific transcript (XIST) in GC. The expression of XIST and EPHA1 in GC tissues and cells was measured. Then, dual luciferase reporter gene assay, RNA immunoprecipitation (RIP) assay and Chromatin Immunoprecipitation (ChIP) assay were performed to explore the interaction among XIST, EPHA1 and HNF4A. The effects of XIST on GG progression were evaluated by determining expression of proliferation- and invasion-related proteins (Ki67, PCNA, MMP-2, and MMP-9). Further, the functional role of XIST in GC with the involvement of NFκB pathway was also analyzed. Subsequently, the tumor growth in nude mice was evaluated. High expression of XIST and EPHA1 was observed in GC. XIST elevated EPHA1 expression by recruiting HNF4A. In addition, silencing of XIST inhibited GC progression in vitro and in vivo. Overexpressed XIST and EPHA1 yielded a reversed effect on cell proliferation and invasion. SN50 treatment (inhibitor of NFκB pathway) counteracted the promotive effect on GC cell proliferation and invasion mediated by XIST. The present study unveils that XIST increases the enrichment of HNF4A in the promoter region of EPHA1, thus promoting the deterioration of GC.

Characterization of inulin-type fructans from two species of Radix Codonopsis and their oxidative defense activation and prebiotic activities

BACKGROUND

Codonopsis pilosula and C. tangshen are both plants widely used in traditional Chinese medicine. Polysaccharides, which are their primary active components, are thought to be important in their extensive use. In this study, two neutral polysaccharide fractions of C. pilosula (CPPN) and C. tangshen (CTPN) were obtained by fractionation on a DEAE-Sepharose column and characterized.

RESULTS

It was confirmed that the neutral polymers CPPN and CTPN were β-(2,1)-linked inulin-type fructans with non-reducing terminal glucose, and degree of polymerization (DP) of 19.6 and 25.2, respectively. The antioxidant and prebiotic activities in vitro were assayed based on IPEC-J2 cell lines and five strains of Lactobacillus. Results indicated that the effects of CPPN and CTPN were increased antioxidant defense in intestinal epithelial cells through enhanced cell viability, improved expression of total antioxidant capacity, glutathione peroxidase, superoxide dismutase and catalase, and reduced levels of malondialdehyde and lactic dehydrogenase. The prebiotic activity of CPPN and CTPN was demonstrated by the promoting effect on Lactobacillus proliferation in vitro. The different biological activities obtained between the two fractions are probably due to the different DP and thus molecular weights of CPPN and CTPN.

CONCLUSION

The inulin fractions from C. pilosula and C. tangshen were natural sources of potential intestinal antioxidants as well as prebiotics, which will be valuable in further studies and new applications of inulin-containing health products. © 2020 Society of Chemical Industry.

Graphene Oxide Membranes for Tunable Ion Sieving in Acidic Radioactive Waste

Graphene oxide (GO) membranes with unique nanolayer structure have demonstrated excellent separation capability based on their size-selective effect, but there are few reports on achieving ion-ion separation, because it is difficult to inhibit the swelling effect of GO nano sheets as well as to precisely control the interlayer spacing d to a specific value between the sizes of different metal ions. Here, selective separation of uranium from acidic radioactive waste containing multication is achieved through a precise dual-adjustment strategy on d. It is found that GO swelling is greatly restricted in highly acidic solution due to protonation effect. Then the interlayer spacing is further precisely reduced to below the diameter of uranyl ion by increasing the oxidation degree of GO. Sieving uranyl ions from other nuclide ions is successfully realized in pH =3-3 mol L-1 nitric acid solutions.

Association between fluoroquinolone utilization rates and susceptibilities of gram-negative bacilli: Results from an 8-year intervention by an antibiotic stewardship program in an inner-city United States hospital

This study evaluated an antibiotic stewardship program (ASP) intervention aimed at reducing inpatient fluoroquinolone (FQ) use and examined its impact on ciprofloxacin susceptibilities of gram-negative bacteria in a large 611-bed community hospital. A two-step ASP intervention was implemented: an electronic medical record algorithm that prompted physicians to re-evaluate FQ use shortly after admission and changed institutional UTI/pneumonia guidelines that recommended options alternate to FQs for first-line empiric antibiotic therapy in 2010 and 2011 respectively. Between 2007 and 2017 FQ use and ciprofloxacin susceptibilities of all non-duplicate cultured isolates of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa obtained ≥72 h after admission were reviewed. Ambulatory care isolates served as a comparison group. FQ utilization rates and relationships to ciprofloxacin susceptibility were evaluated using interrupted time series models. Over the 11-year period, FQ use decreased from 110.0 (2007) to 26.2 (2017) days of therapy/1000 days at risk (p < 0.001). Compared to pre-intervention, the estimated (post-intervention) reduction in FQ utilization was 28.4 (95% CI: 10.9-46) days of therapy/1000 days at risk. Reduced FQ utilization was correlated with increase susceptibilities to ciprofloxacin of hospital onset isolates of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis (p < 0.02), and Pseudomonas aeruginosa (p = 0.07). No significant susceptibility change was observed in the ambulatory care isolates. Persuasive interventions by an ASP successfully modified physicians' inpatient empiric antibiotic use, produced a sustained reduction in FQ utilization rates and increased ciprofloxacin susceptibility to four commonly encountered gram-negative bacteria in a community hospital.

Comparative transcriptome profile analysis of rice varieties with different tolerance to zinc deficiency

Zinc (Zn) is an indispensable element for rice growth. Zn deficiency results in brown blotches and streaks 2-3 weeks after transplanting, as well as stunting, reduced tillering, and low productivity of rice plants. These processes are controlled by different families of expressed genes. A comparative transcriptome profile analysis was conducted using the roots of two Zn deficiency tolerant varieties (UCP122 and KALIBORO26) and two sensitive varieties (IR26 and IR64) by merging data from untreated control (CK) and Zn deficiency treated samples. Results revealed a total of 4,688 differentially expressed genes (DEGs) between the normal Zn and deficient conditions, with 2,702 and 1,489 unique DEGs upregulated and downregulated, respectively. Functional enrichment analysis identified transcription factors (TFs), such as WRKY, MYB, ERF, and bHLH which are important in the regulation of the Zn deficiency response. Furthermore, chitinases, jasmonic acid, and phenylpropanoid pathways were found to be important in the Zn deficiency response. The metal tolerance protein (MTP) genes also appeared to play an important role in conferring tolerance to Zn deficiency. A heavy metal-associated domain-containing protein 7 was associated with tolerance to Zn deficiency and negatively regulated downstream genes. Collectively, our findings provide valuable expression patterns and candidate genes for the study of molecular mechanisms underlying the response to Zn deficiency and for improvements in breeding for tolerance to Zn deficiency in rice.

Silver Nanoparticles Induced Oxidative Stress and Mitochondrial Injuries Mediated Autophagy in HC11 Cells Through Akt/AMPK/mTOR Pathway

Silver nanoparticles (AgNPs) are widely used in industrial products, and they have good antibacterial properties, with potential for prevention and treatment of cow mastitis. However, concerns exist about the cytotoxicity of AgNPs. Thus, we have studied the role of autophagy in AgNP-induced cytotoxicity in mouse HC11 mammary epithelium cells. We found that AgNPs injured HC11 cells, with release of lactate dehydrogenase (LDH). AgNPs also induced autophagy in HC11 cells, which was associated with oxidative stress, as indicated by increased reactive oxygen species (ROS) and increased expression of hemoxygenase-1(HO-1) and Nrf2. Mitochondria were altered by AgNPs: mitochondrial membrane potential (MMP) was decreased and the expression of PINK1 and Parkin was increased. AgNPs also increased the expression of p-AMPK and decreased the expression of p-Akt and p-mTOR. The addition of 3-methyl adenine inhibited autophagy and enhanced the cytotoxicity of AgNPs, indicating that autophagy is protective against AgNP-induced cell death. In summary, AgNPs induced protective autophagy in HC11 cells via the Akt/AMPK/mTOR pathway, associated with cellular oxidative stress and mitochondrial alterations. Our research confirms that AgNPs may damage the breast tissue in clinical applications and should be used with caution. Further research is necessary to clarify whether the damage caused by AgNPs will affect the lactation function of the mammary glands and possible residues in milk.

Characterization of an antioxidant pectic polysaccharide from Platycodon grandiflorus

Platycodonis Radix is widely used as homology of medicine and food in China; polysaccharides are thought to be one of its functional constituents. In this study, a pectic polysaccharide, PGP-I-I, was obtained from the root of the traditional medicine plant Platycodon grandiflorus through ion exchange chromatography and gel filtration. This was characterized being mainly composed of 1,5-α-L-arabinan and both arabinogalactan type I (AG-I) and II chains linked to rhamnogalacturonan I (RG-I) backbone linked to longer galacturonan chains. In vitro bioactivity study showed that PGP-I-I could restore the intestinal cellular antioxidant defense under the condition of hydrogen peroxide (H₂O₂) treatment through promoting the expressions of cellular antioxidant genes and protect against oxidative damages.

Metagenomics Reveals That Intravenous Injection of Beta-Hydroxybutyric Acid (BHBA) Disturbs the Nasopharynx Microflora and Increases the Risk of Respiratory Diseases

It is widely accepted that maintenance of microbial diversity is essential for the health of the respiratory tract; however, there are limited reports on the correlation between starvation and respiratory tract microbial diversity. In the present study, saline/β-hydroxybutyric acid (BHBA) intravenous injection after dietary restriction was used to imitate different degrees of starvation. A total of 13 healthy male yaks were imposed to different dietary restrictions and intravenous injections, and their nasopharyngeal microbiota profiles were obtained by metagenomic shotgun sequencing. In healthy yaks, the main dominant phyla were Proteobacteria (33.0%), Firmicutes (22.6%), Bacteroidetes (17.2%), and Actinobacteria (13.2%); the most dominated species was Clostridium botulinum (10.8%). It was found that 9 days of dietary restriction and 2 days of BHBA injection (imitating severe starvation) significantly decreased the microbial diversity and disturbed its structure and functional composition, which increased the risk of respiratory diseases. This study also implied that oral bacteria played an important role in maintaining nasopharynx microbial homeostasis. In this study, the correlation between starvation and nasopharynx microbial diversity and its potential mechanism was investigated for the first time, providing new ideas for the prevention of respiratory diseases.

Hsa_circ_0000515 is a novel circular RNA implicated in the development of breast cancer through its regulation of the microRNA-296-5p/CXCL10 axis

Cancer metastasis is a major cause of death among women afflicted with breast cancer (BC) and understanding the molecular processes involved is a major focus in BC research. Circular RNAs (circRNAs) have emerged as genomic regulatory molecules in carcinogenesis and metastasis; however, their role in BC is unclear. We characterized a novel circRNA, hsa_circ_0000515, in context of BC. We collected 340 cancerous tissues surgically resected from BC patients and found hsa_circ_0000515 was upregulated in BC tissues and associated with poor prognosis of BC. Silencing of hsa_circ_0000515 impaired cell cycle progression, cell proliferation, and invasion, attenuated inflammatory response, and reduced the proangiogenetic potential of BC cells. RNA pull-down and dual-luciferase reporter gene assays showed that hsa_circ_0000515 binds miR-296-5p, preventing it from repressing CXCL10 expression. We also observed that miR-296-5p inhibition or CXCL10 overexpression promoted cell cycle progression, restored proliferative, invasive and proangiogenetic abilities, and increased inflammatory response in MCF-7 cells in the absence of hsa_circ_0000515. In vivo analyses showed that partial loss of hsa_circ_0000515 reduced the tumor growth of MCF-7 cells in nude mice. The key findings from this study revealed that targeting hsa_circ_0000515 might be an effective strategy to combat BC.

Expression and Functional Characterization of c-Fos Gene in Chinese Fire-Bellied Newt Cynops Orientalis

c-Fos is an immediate-early gene that modulates cellular responses to a wide variety of stimuli and also plays an important role in tissue regeneration. However, the sequence and functions of c-Fos are still poorly understood in newts. This study describes the molecular cloning and characterization of the c-Fos gene (Co-c-Fos) of the Chinese fire-bellied newt, Cynops orientalis. The full-length Co-c-Fos cDNA sequence consists of a 1290 bp coding sequence that encoded 429 amino acids. The alignment and phylogenetic analyses reveal that the amino acid sequence of Co-c-Fos shared a conserved basic leucine zipper domain, including a nuclear localization sequence and a leucine heptad repeat. The Co-c-Fos mRNA is widely expressed in various tissues and is highly and uniformly expressed along the newt limb. After limb amputation, the expression of Co-c-Fos mRNA was immediately upregulated, but rapidly declined. However, the significant upregulation of Co-c-Fos protein expression was sustained for 24 h, overlapping with the wound healing stage of C. orientalis limb regeneration. To investigate if Co-c-Fos participate in newt wound healing, a skin wound healing model is employed. The results show that the treatment of T-5224, a selective c-Fos inhibitor, could largely impair the healing process of newt’s skin wound, as well as the injury-induced matrix metalloproteinase-3 upregulation, which is fundamental to wound epithelium formation. These data suggest that Co-c-Fos might participate in wound healing by modulating the expression of its potential target gene matrix metalloproteinase-3. Our study provides important insights into mechanisms that are responsible for the initiation of newt limb regeneration.

Structure of the multiple functional domains from coronavirus nonstructural protein 3

Coronaviruses (CoVs) are potential pandemic pathogens that can infect a variety of hosts and cause respiratory, enteric, hepatic and neurological diseases. Nonstructural protein 3 (nsp3), an essential component of the replication/transcription complex, is one of the most important antiviral targets. Here, we report the first crystal structure of multiple functional domains from porcine delta-coronavirus (PDCoV) nsp3, including the macro domain (Macro), ubiquitin-like domain 2 (Ubl2) and papain-like protease (PLpro) catalytic domain. In the asymmetric unit, two of the subunits form the head-to-tail homodimer with an interaction interface between Macro and PLpro. However, PDCoV Macro-Ubl2-PLpro mainly exists as a monomer in solution. Then, we conducted fluorescent resonance energy transfer-based protease assays and found that PDCoV PLpro can cleave a peptide by mimicking the cognate nsp2/nsp3 cleavage site in peptide substrates and exhibits deubiquitinating and de-interferon stimulated gene(deISGylating) activities by hydrolysing ubiquitin-7-amino-4-methylcoumarin (Ub-AMC) and ISG15-AMC substrates. Moreover, the deletion of Macro or Macro-Ubl2 decreased the enzyme activity of PLpro, indicating that Macro and Ubl2 play important roles in maintaining the stability of the PLpro domain. Two active sites of PLpro, Cys260 and His398, were determined; unexpectedly, the conserved site Asp412 was not the third active site. Furthermore, the motif "NGYDT" (amino acids 409-413) was important for stabilizing the enzyme activity of PLpro, and the N409A mutant significantly decreased the enzyme activity of PLpro. These results provide novel insights into the replication mechanism of CoV and new clues for future drug design.