Peripheral blood Apolipoprotein E (ApoE) levels have been proposed as biomarkers of Alzheimer’s disease (AD), but previous studies on levels of ApoE in blood remain inconsistent. This meta-analysis was designed to re-examine the potential role of peripheral ApoE in AD diagnosis and its potential value as a candidate biomarker.
We conducted a systematic literature search of MEDLINE, EMBASE, the Cochrane library, and BIOSIS previews for case-control studies measuring ApoE levels in serum or plasma from AD subjects and healthy controls. The pooled weighted mean difference (WMD) and 95% confidence interval (CI) were used to estimate the association between ApoE levels and AD risk.
Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed. The pooled WMD from a random-effect model of AD participants compared with the healthy controls was −5.59 mg/l (95% CI: [−8.12, −3.06]). The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.
Our meta-analysis supports a lowered level of blood ApoE in AD patients, and indicates its potential value as an important risk factor for AD. Further investigation employing standardized assay for ApoE measurement are still warranted to uncover the precise role of ApoE in the pathophysiology of AD.
Ribose-phosphate pyrophosphokinase 1 (PRPS1) was identified and isolated as a differentially expressed gene between deltamethrin-susceptible (DS) and deltamethrin-resistant (DR) Culex pipiens pallens and Aedes albopictus C6/36 cell line through microarray and 2D-Gel. An open reading frame of PRPS1 cloned from C. pipiens pallens has 1,011 bp and encodes for a 336 amino acids protein which shares high homology with Culex quinquefasciatus. Real-time polymerase chain reaction was used to determine the transcript expression level of PRPS1 in DS and DR strains. The expression levels of PRPS1 were higher in DR laboratory strains and natural population JXZ-DR, JXZ-LDR. PRPS1 was also detected and expressed at all developmental stages of C. pipiens pallens and increased expression level in DR3 strain than DS strain in the third and fourth instar larvae, female and male stages. In addition, to further investigate the role of PRPS1 in deltamethrin resistance, PRPS1 was transiently expressed in A. albopictus C6/36 cells and detected by western blotting. Cells transfected with PRPS1 had an increased resistance to deltamethrin compared with control cells. These results suggested that the increased expression level of PRPS1 may play roles in the regulation of deltamethrin resistance.
Anopheles sinensis is an important mosquito vector of Plasmodium vivax, which is the most frequent and widely distributed cause of recurring malaria throughout Asia, and particularly in China, Korea, and Japan.
We performed 454 next-generation sequencing and obtained a draft sequence of A. sinensis assembled into scaffolds spanning 220.8 million base pairs. Analysis of this genome sequence, we observed expansion and contraction of several immune-related gene families in anopheline relative to culicine mosquito species. These differences suggest that species-specific immune responses to Plasmodium invasion underpin the biological differences in susceptibility to Plasmodium infection that characterize these two mosquito subfamilies.
The A. sinensis genome produced in this study, provides an important resource for analyzing the genetic basis of susceptibility and resistance of mosquitoes to Plasmodium parasites research which will ultimately facilitate the design of urgently needed interventions against this debilitating mosquito-borne disease.
Genome; Anopheles sinensis; Malaria
AIM: To assess the potential benefits of mosapride plus proton pump inhibitors (PPIs) in the treatment of gastroesophageal reflux disease.
METHODS: A literature search was performed through MEDLINE, EMBASE, and the ISI Web of Knowledge. The clinical trials that compared the benefit of mosapride plus PPI treatment with that of PPI monotherapy were analyzed. The rate of responders was evaluated by the pooled relative risk (PRR) and improvement in symptom scores was assessed by single effect size of a standardized mean, while Hedges’g was used as the effect size. Pooled effect sizes with 95%CIs were calculated using a fixed-effects model. Between-study heterogeneity was assessed using Q test and I2 analyses. In addition, studies that assessed the additional efficacy of mosapride in PPI-resistant patients were also reviewed.
RESULTS: This systematic review included information on a total of 587 patients based on 7 trials. Four trials compared the efficacy of combination therapy of mosapride plus a PPI with that of PPI monotherapy. The statistical analysis for the effect of additional mosapride showed equivocal results (PRR = 1.132; 95%CI: 0.934-1.372; P = 0.205; Hedges’g = 0.24; 95%CI: 0.03-0.46; P = 0.023). No heterogeneity and publication bias were found among the studies. Three open-labeled trials assessed the additional efficacy of mosapride in PPI-resistant patients. However, since these trials did not set the control group, the results may be considerably biased.
CONCLUSION: Mosapride combined therapy is not more effective than PPI alone as first-line therapy. Whether it is effective in PPI-resistant patients needs to be determined.
Mosapride; Proton pump inhibitor; Gastroesophageal reflux disease; Systematic review; Combined therapy
Post-transcriptional regulatory mechanisms are of fundamental importance to form robust genetic networks, but their roles in stem cell pluripotency remain poorly understood. Here, we use freshwater planarians as a model system to investigate this and uncover a role for CCR4-NOT mediated deadenylation of mRNAs in stem cell differentiation. Planarian adult stem cells, the so-called neoblasts, drive the almost unlimited regenerative capabilities of planarians and allow their ongoing homeostatic tissue turnover. While many genes have been demonstrated to be required for these processes, currently almost no mechanistic insight is available into their regulation. We show that knockdown of planarian Not1, the CCR4-NOT deadenylating complex scaffolding subunit, abrogates regeneration and normal homeostasis. This abrogation is primarily due to severe impairment of their differentiation potential. We describe a stem cell specific increase in the mRNA levels of key neoblast genes after Smed-not1 knock down, consistent with a role of the CCR4-NOT complex in degradation of neoblast mRNAs upon the onset of differentiation. We also observe a stem cell specific increase in the frequency of longer poly(A) tails in these same mRNAs, showing that stem cells after Smed-not1 knock down fail to differentiate as they accumulate populations of transcripts with longer poly(A) tails. As other transcripts are unaffected our data hint at a targeted regulation of these key stem cell mRNAs by post-transcriptional regulators such as RNA-binding proteins or microRNAs. Together, our results show that the CCR4-NOT complex is crucial for stem cell differentiation and controls stem cell-specific degradation of mRNAs, thus providing clear mechanistic insight into this aspect of neoblast biology.
Although transcriptional regulation in stem cells is a very active subject, much less is known about how post-transcriptional mechanisms of gene expression affect stem cells. Here, we use freshwater planarians in order to address this question. Planarians have a striking regenerative capacity driven by a population of pluripotent stem cells, the neoblasts. Control of both proliferation and differentiation is thought to rely heavily on post-transcriptional mechanisms, but their precise role is unknown. Poly(A) tail length regulation is an important mechanism of post-transcriptional control of gene expression as changes can be very rapid, and longer poly(A) tails are linked to increased mRNA stability and translational activity. We investigated the role of the CCR4-NOT complex, the major deadenylating complex in eukaryotes, by knocking down its main scaffolding subunit called Not1. Neoblasts in knock down animals are unable to differentiate and accumulate mRNAs with longer poly(A) tails. Our results show that the CCR4-NOT complex is needed for the targeted degradation of specific mRNAs expressed in stem cells, and the failure of this process likely prevents neoblasts from differentiating. These results reveal a new functional aspect of the CCR4-NOT complex and offer a mechanistic insight into the regulation of planarian stem cells.
Anti-apoptotic Bcl-2 family proteins, in particular, Mcl-1, are known to play a critical role in resistance of human melanoma cells to induction of apoptosis by endoplasmic reticulum stress and other agents. The present study examined whether the BH3 mimetics, Obatoclax and ABT-737, which inhibit multiple anti-apoptotic Bcl-2 family proteins, would overcome resistance to apoptosis. We report that both agents induced a strong unfolded protein response (UPR) and that RNAi knockdown of UPR signalling proteins ATF6, IRE1α and XBP-1 inhibited Mcl-1 upregulation and increased sensitivity to the agents. These results demonstrate that inhibition of anti-apoptotic Bcl-2 proteins by Obatoclax and ABT-737 appears to elicit a protective feedback response in melanoma cells, by upregulation of Mcl-1 via induction of the UPR. We also report that Obatoclax, but not ABT-737, strongly induces autophagy, which appears to play a role in determining melanoma sensitivity to the agents.
Nasopharyngeal carcinoma is a common malignant tumor in the head and neck. Because of frequent recurrence and distant metastasis which are the main causes of death, better treatment is needed. Indole-3-carbinol (I3C), a natural phytochemical found in the vegetables of the cruciferous family, shows anticancer effect through various signal pathways. I3C induces G1 arrest in NPC cell line with downregulation of cell cycle-related proteins, such as CDK4, CDK6, cyclin D1 and pRb. In vivo, nude mice receiving I3C protectively or therapeutically exhibited smaller tumors than control group after they were inoculated with nasopharyngeal carcinoma cells. The expression of CDK4, CDK6, cyclin D1 and pRb in preventive treatment group and drug treatment group both decreased compared with the control group. We conclude that I3C can inhibit the growth of NPC in vitro and in vivo by suppressing the expression of CDK and cyclin families. The drug was safe and had no toxic effects on normal tissues and organs.
A current prevalence and relevant risk factors for impaired fasting glucose (IFG) have been reported by various ethnic groups and countries. By contrast, nationwide data for the incidence of IFG in Taiwan have not been presented in the past 15 years. The aim for this manuscript was to estimate the prevalence of IFG and associated risk factors in the population of Taiwan.
For this cross-sectional research, we used a nationally representative sample (N = 2604) obtained from the 2005–2008 Nutrition and Health Survey in Taiwan (NAHSIT), and adopted a stratified multistage sampling design. The tools employed for data collection included questionnaire interviews, anthropometry measurements, and laboratory analysis.
The prevalence of IFG among adults in Taiwan is 35.8% (a fasting glucose level between 100 and 125 mg/dl is considered abnormal). An estimated number of people with IFG is 6.5 million. A higher prevalence of IFG is observed in men younger than 65 years compared to women. However, this trend is reversed for the elderly population. The factors significantly associated with IFG include the following: sex, age, overweight (27 > BMI ≥ 24), obesity (BMI ≥ 27), waist circumference (men ≥ 90 cm, women ≥ 80 cm), hypertension, and hyperlipidemia.
IFG among adults in Taiwan is a health concern that requires attention. We recommend targeting the younger population, especially overweight and obese men between the ages of 19 and 40 years, to provide applicable healthy lifestyle counseling and services. Furthermore, appropriate screening of elderly people is required to detect undiagnosed IFG cases and provide early intervention and treatment.
Impaired fasting glucose (IFG); Prevalence; Adult; Epidemiology; Taiwan
In the title compound, C21H26O2SSe, the S atom adopts a pyramidal geometry (bond-angle sum = 304°) and the n-butyl chain shows an extended conformation. An intramolecular C—H⋯O hydrogen bond closes an S(8) ring. In the crystal, inversion dimers are formed with molecules linked by pairs of O—H⋯O=S hydrogen bonds, generating R
2(14) loops. Weak C—H⋯O interactions also occur.
Planarian adult stem cells (pASCs) or neoblasts represent an ideal system to study the evolution of stem cells and pluripotency as they underpin an unrivaled capacity for regeneration. We wish to understand the control of differentiation and pluripotency in pASCs and to understand how conserved, convergent or divergent these mechanisms are across the Bilateria. Here we show the planarian methyl-CpG Binding Domain 2/3 (mbd2/3) gene is required for pASC differentiation during regeneration and tissue homeostasis. The genome does not have detectable levels of 5-methylcytosine (5mC) and we find no role for a potential DNA methylase. We conclude that MBD proteins may have had an ancient role in broadly controlling animal stem cell pluripotency, but that DNA methylation is not involved in planarian stem cell differentiation.
•A single ancestral MBD2/3 protein is present in the planarian Schmidtea mediterranea.•The genome of S. mediterranea does not have pervasive cytosine methylation.•MBD2/3 is required for pluripotent stem cell differentiation down multiple but not all cell lineages.•MBD2/3 may have had an ancestral role in regulating stem cell pluripotency.
Methyl binding domain; Pluripotency; Differentiation; Regeneration
Two novel cyclodepsipeptides containing an unusual anthranilic acid dimer and a d-phenyllactic acid residues, clavatustides A (1) and B (2), were identified from cultured mycelia and broth of Aspergillus clavatus C2WU isolated from Xenograpsus testudinatus, which lives at extreme, toxic habitat around the sulphur-rich hydrothermal vents in Taiwan Kueishantao. This is the first example of cyclopeptides containing an anthranilic acid dimer in natural products, and the first report of microbial secondary metabolites from the hydrothermal vent crab. Clavatustides A (1) and B (2) suppressed the proliferation of hepatocellular carcinoma (HCC) cell lines (HepG2, SMMC-7721 and Bel-7402) in a dose-dependent manner, and induced an accumulation of HepG2 cells in G1 phase and reduction of cells in S phase.
cyclodepsipeptide; Aspergillus clavatus; hydrothermal vent; carcinoma cycle inhibitory
Unlike those infected by H5N1, birds infected by the newly discovered H7N9 virus have no observable clinical symptoms. Public health workers in China do not know where the public health threat lies. In this study, we used a distributed focused crawler to analyze online knowledge of the live bird trade in first-wave provinces, namely, Jiangsu, Zhejiang, Anhui, and Shanghai, to track the new H7N9 virus and predict its spread. Of the 18 provinces proposed to be at high risk of infection, 10 reported human infections and one had poultry specimens that tested positive. Five provinces (Xinjiang, Yunnan, Guizhou, Shaanxi, and Tibet) as well as Hong Kong, Macao, and Taiwan were proposed to have no risk of H7N9 virus infection from the live bird trade. These data can help health authorities and the public to respond rapidly to reduce damage related to the spread of the virus.
H7N9; online knowledge; outbreak
Recently, plasma miRNAs have been reported as biomarkers for various diseases. However, the knowledge on the association of plasma miRNAs with ischemic stroke is still lacking. In this study, we investigated whether plasma concentrations of miR-30a, miR-126 and let-7b may be biomarkers for ischemic stroke in humans.
One hundred ninety seven patients with ischemic stroke were recruited and their blood samples were collected at 24 h, 1 week, 4 weeks, 24 weeks and 48 weeks after symptoms onset, and fifty healthy volunteers were selected as control. Levels of miRNA were quantified by quantitative real-time PCR. Relative expression level of miRNA was calculated using 2-ΔΔct method. The ability to distinguish the ischemic stroke group from control group was characterized by receiver operating characteristic (ROC) curve, and the area under ROC curve (AUC) was calculated.
Circulating miR-30a and miR-126 levels were markedly down-regulated in all patients with ischemic stroke until 24 weeks. However, circulating let-7b was lower in patients with large-vessel atherosclerosis than healthy volunteers, whereas circulating let-7b had higher level in patients with other kinds of ischemic stroke until 24 weeks. Among all patients, circulating miRNAs levels returned to normal 48 weeks after symptom onset. Receiver operating characteristic (ROC) curve analysis showed that the areas under the curve (AUC) of plasma miR-30a were 0.91, 0.91, 0.92 and 0.93, the miR-126 were 0.92, 0.94, 0.93 and 0.92, and let-7b were 0.93, 0.92, 0.92 and 0.91 at 24 h, 1 w, 4 w and 24 w, respectively.
These data suggest that miR-30a, miR-126 and let-7b might be useful biomarkers for ischemic stroke in humans.
Circulating miRNA; Biomarker; Stroke
We selected 180 clinical isolates of the Mycobacterium tuberculosis complex (MTBC) from patients in China and performed comparative sequence analysis of the mpt64 gene after amplification. From the results, we found that polymorphisms of the mpt64 gene in the MTBC may be the reason for changes in the antigen produced, which may in turn cause alterations of related functions, thereby allowing immune evasion.
Resin bonding to zirconia cannot be established from standard methods that are currently utilized in conventional silica-based dental ceramics. The solution–gelatin (sol–gel) process is a well developed silica-coating technique used to modify the surface of nonsilica-based ceramics. Here, we use this technique to improve resin bonding to zirconia, which we compared to zirconia surfaces treated with alumina sandblasting and tribochemical silica coating. We used the shear bond strength test to examine the effect of the various coatings on the short-term resin bonding of zirconia. Furthermore, we employed field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier transform infrared spectroscopy to characterize the zirconia surfaces. Water–mist spraying was used to evaluate the durability of the coatings. To evaluate the biological safety of the experimental sol–gel silica coating, we conducted an in vitro Salmonella typhimurium reverse mutation assay (Ames mutagenicity test), cytotoxicity tests, and in vivo oral mucous membrane irritation tests. When compared to the conventional tribochemical silica coating, the experimental sol–gel silica coating provided the same shear bond strength, higher silicon contents, and better durability. Moreover, we observed no apparent mutagenicity, cytotoxicity, or irritation in this study. Therefore, the sol–gel technique represents a promising method for producing silica coatings on zirconia.
zirconia; bond; silica coating; tribochemical silica coating; biocompatibility
Chemical doping in materials is known to give rise to emergent phenomena. These phenomena are extremely difficult to predict a priori, because electron-electron interactions are entangled with local environment of assembled atoms. Scanning tunneling microscopy and low energy electron diffraction are combined to investigate how the local electronic structure is correlated with lattice distortion on the surface of Sr3(Ru1−xMnx)2O7, which has double-layer building blocks formed by (Ru/Mn)O6 octahedra with rotational distortion. The presence of doping-dependent tilt distortion of (Ru/Mn)O6 octahedra at the surface results in a C2v broken symmetry in contrast with the bulk C4v counterpart. It also enables us to observe two Mn sites associated with the octahedral rotation in the bulk through the “chirality” of local electronic density of states surrounding Mn, which is randomly distributed. These results serve as fingerprint of chemical doping on the atomic scale.
Cytokines such as IL-6 and G-CSF are important metastasis promoters. This study has investigated the functional significance of the increased circulation of galectin-3, a common feature in cancer patients and in particular those with metastasis, on cytokine secretion from the blood vascular endothelium in cancer.
The effects of galectin-3 on secretion of cytokines from human microvascular lung endothelial cells were assessed in vitro by cytokine array and in vivo in mice. The consequences of galectin-3-induced cytokine secretion on endothelial cell behaviors were determined and the relationship between the levels of circulating galectin-3 and cytokines in colorectal cancer patients with and without metastasis was investigated.
Galectin-3 at pathological concentrations found in cancer patients induces secretion of IL-6, G-CSF, sICAM-1 and GM-CSF from blood vascular endothelial cells in vitro and in mice. These cytokines autocrinely/paracrinely interact with the vascular endothelium to increase the expressions of endothelial cell surface adhesion molecules integrinαvβ1, E-selectin, ICAM-1 and VCAM-1, resulting in increased cancer cell-endothelial adhesion and increased endothelial cell migration and tubule formation. In patients with metastatic colon cancer, higher serum galectin-3 levels correlated significantly with increased serum G-CSF, IL-6 and sICAM1 concentrations.
The increased circulation of galectin-3 in cancer patients induces secretion of several metastasis-promoting cytokines from the blood vascular endothelium that enhances endothelial cell activities in metastasis. Targeting the actions of circulating galectin-3 in cancer patients therefore represents a promising therapeutic strategy to reduce metastasis and improve survival.
galectin-3; cytokines; adhesion; metastasis
TRIP6 is an adaptor protein that regulates cell motility and antiapoptotic signaling. Although it has been implicated in tumorigenesis, the underlying mechanism remains largely unknown. Here we provide evidence that TRIP6 promotes tumorigenesis by serving as a bridge to promote the recruitment of p27KIP1 to AKT in the cytosol. TRIP6 regulates the membrane translocation and activation of AKT and facilitates AKT-mediated recognition and phosphorylation of p27KIP1 specifically at T157, thereby promoting the cytosolic mislocalization of p27KIP1. This is required for p27KIP1 to enhance lysophosphatidic acid (LPA)-induced ovarian cancer cell migration. TRIP6 also promotes serum-induced reduction of nuclear p27KIP1 expression levels through Skp2-dependent and -independent mechanisms. Consequently, knockdown of TRIP6 in glioblastoma or ovarian cancer xenografts restores nuclear p27KIP1 expression and impairs tumor proliferation. As TRIP6 is upregulated in gliomas and its levels correlate with poor clinical outcomes in a dose-dependent manner, it may represent a novel prognostic marker and therapeutic target in gliomas.
Previous study demonstrated that miR-133a was released into blood from injured myocardium in cardiovascular diseases. However, the dynamic change of circulating miR-133a level in the early phase of acute myocardial infarction (AMI) and the correlation between miR-133a and severity of coronary stenosis in coronary heart disease (CHD) patients are not clear.
Methods and results
Three different cohorts (including 13 AMI patients, 176 angina pectoris patients and 127 control subjects) were enrolled to investigate the expression levels of circulating miR-133a in patients with myocardial ischemia and also the relationship between plasma miR-133a and severity of coronary stenosis. Plasma miR-133a levels of participants were examined by real-time quantitative PCR. Simultaneously, plasma cardiac troponin I (cTnI) concentrations were measured by ELISA assays. The results showed that circulating miR-133a level was significantly increased in AMI patients in time-dependent manner, and achieved a 72.1 fold peak at 21.6 ± 4.5 hours after the onset of AMI symptoms and exhibited a similar trend to plasma cTnI level. We also found that plasma miR-133a levels were higher in CHD patients than control group. Importantly, the levels of circulating miR-133a positively correlated with the severities of the coronary artery stenosis. Receiver operating characteristic (ROC) analysis revealed that circulating miR-133a had considerable diagnostic accuracy for CHD with an AUC of 0.918 (95% confidence interval 0.877-0.960).
Circulating miR-133a may be a new biomarker for AMI and as a potential diagnostic tool. And increased miR-133a level may be used to predict both the presence and severity of coronary lesions in CHD patients.
Biomarker; CHD; Circulating miRNA
E-readers are fast rivaling print as a dominant method for reading. Because they offer accessibility options that are impossible in print, they are potentially beneficial for those with impairments, such as dyslexia. Yet, little is known about how the use of these devices influences reading in those who struggle. Here, we observe reading comprehension and speed in 103 high school students with dyslexia. Reading on paper was compared with reading on a small handheld e-reader device, formatted to display few words per line. We found that use of the device significantly improved speed and comprehension, when compared with traditional presentations on paper for specific subsets of these individuals: Those who struggled most with phoneme decoding or efficient sight word reading read more rapidly using the device, and those with limited VA Spans gained in comprehension. Prior eye tracking studies demonstrated that short lines facilitate reading in dyslexia, suggesting that it is the use of short lines (and not the device per se) that leads to the observed benefits. We propose that these findings may be understood as a consequence of visual attention deficits, in some with dyslexia, that make it difficult to allocate attention to uncrowded text near fixation, as the gaze advances during reading. Short lines ameliorate this by guiding attention to the uncrowded span.
The association of functional polymorphisms in the promoter of the apoptosis gene FAS with systemic lupus erythematosus (SLE) susceptibility has been a controversial subject. We conducted a case-control study to investigate this association in a Chinese population and performed a meta-analysis in different populations. The single nucleotide polymorphisms (SNPs) rs2234767 (−1377G>A) and rs1800682 (−670A>G) were genotyped by TaqMan allelic discrimination assays in 552 Chinese SLE patients and 718 healthy controls. In our case-control study, we observed allelic association between the promoter SNP rs2234767 [P=0.033, odds ratio (OR)=0.836, 95% confidence interval (CI), 0.709–0.986] and SLE but not the SNP rs1800682. Haplotype analysis revealed that one haplotype of GA was significantly associated with the disease (P=0.039, OR=1.184, 95% CI, 1.009–1.391). In the meta-analysis available studies, including our data, were combined using the STATA software package v.7.0. The meta-analysis revealed a significant association between FAS polymorphisms and SLE (rs2234767 A vs. G allele; P=0.004, OR=0.819, 95% CI, 0.715–0.938, rs1800682 G vs. A allele: P=0.034, OR=0.791, 95% CI, 0.637–0.983). In conclusion, FAS gene polymorphisms may contribute to SLE susceptibility in the Chinese population, and the meta-analysis shows that FAS polymorphisms may be associated with SLE susceptibility in different populations.
systemic lupus erythematosus; FAS; single-nucleotide polymorphisms; meta-analysis
We report a facile and green method to synthesize a new type of catalyst by coating Pd nanoparticles (NPs) on reduced graphene oxide (rGO)-carbon nanotube (CNT) nanocomposite. An rGO–CNT nanocomposite with three-dimensional microstructures was obtained by hydrothermal treatment of an aqueous dispersion of graphene oxide (GO) and CNTs. After the rGO–CNT composites have been dipped in K2PdCl4 solution, the spontaneous redox reaction between the GO–CNT and PdCl42− led to the formation of nanohybrid materials consisting rGO–CNT decorated with 4 nm Pd NPs, which exhibited excellent and stable catalytic activity: the reduction of 4-nitrophenol to 4-aminophenol using NaBH4 as a catalyst was completed in only 20 s at room temperature, even when the Pd content of the catalyst was 1.12 wt%. This method does not require rigorous conditions or toxic agents and thus is a rapid, efficient, and green approach to the fabrication of highly active catalysts.
The microbial community dynamics play an important role during Massa Medicata Fermentata (MMF) fermentation. In this study, bacterial and fungal communities were investigated based on the culture-dependent method and polymerase chain reaction-denaturing gradient gel electrophoresis analysis. Meanwhile the dynamic changes of digestive enzyme activities were also examined. Plating results showed that MMF fermentation comprised two stages: pre-fermentation stage (0–4 days) was dominated by bacterial community and post-fermentation stage (5–9 days) was dominated by fungal community. The amount of bacteria reached the highest copy number 1.2 × 1010 CFU/g at day 2, but the fungi counts reached 6.3 × 105 CFU/g at day 9. A total of 170 isolates were closely related to genera Enterobacter, Klebsiella, Acinetobacter, Pseudomonas, Mucor, Saccharomyces, Rhodotorula, and Amylomyces. DGGE analysis showed a clear reduction of bacterial and fungal diversity during fermentation, and the dominant microbes belonged to genera Enterobacter, Pediococcus, Pseudomonas, Mucor, and Saccharomyces. Digestive enzyme assay showed filter paper activity; the activities of amylase, carboxymethyl cellulase, and lipase reached a peak at day 4; and the protease activity constantly increased until the end of the fermentation. In this study, we carried out a detailed and comprehensive analysis of microbial communities as well as four digestive enzymes' activities during MMF fermentation process. The monitoring of bacterial and fungal biodiversity and dynamics during MMF fermentation has significant potential for controlling the fermentation process.
Massa Medicata Fermentata fermentation; PCR-DGGE; Digestive enzyme; Bacterial community; Fungal community
Background: Esp, a secreted protease of Staphylococcus epidermidis, blocks biofilm formation of Staphylococcus aureus and its ability to colonize human nares.
Results: Esp cleaves autolysin, thereby preventing the release of staphylococcal DNA as biofilm matrix.
Conclusion: Secreted proteases control S. aureus biofilm development and host colonization.
Significance: Methods that promote autolysin degradation may also prevent S. aureus colonization of humans.
Staphylococcus epidermidis, a commensal of humans, secretes Esp protease to prevent Staphylococcus aureus biofilm formation and colonization. Blocking S. aureus colonization may reduce the incidence of invasive infectious diseases; however, the mechanism whereby Esp disrupts biofilms is unknown. We show here that Esp cleaves autolysin (Atl)-derived murein hydrolases and prevents staphylococcal release of DNA, which serves as extracellular matrix in biofilms. The three-dimensional structure of Esp was revealed by x-ray crystallography and shown to be highly similar to that of S. aureus V8 (SspA). Both atl and sspA are necessary for biofilm formation, and purified SspA cleaves Atl-derived murein hydrolases. Thus, S. aureus biofilms are formed via the controlled secretion and proteolysis of autolysin, and this developmental program appears to be perturbed by the Esp protease of S. epidermidis.
Bacterial Pathogenesis; Biofilm; Extracellular Matrix; Serine Protease; Staphylococcus aureus