Strepolyketide D, a new SEK15-derived polyketide compound from salt-lake-derived Streptomyces sp. DBC5.

A new SEK15-derived polyketide compound, strepolyketide D (1), was isolated from salt-lake-derived Streptomyces sp. DBC5, together with two known analogues (2-3). Their structures were elucidated based on spectroscopic analysis of IR, MS, 1 D and 2 D NMR. Compound 2 elicited moderate antioxidation with IC50 value of 39.26 µg/ml. The results of the study revealed that salt-lake actinomycetes of Lake Dabancheng appear to have immense potential as a source of polyketide compounds.

The relationship between obstructive sleep apnea and Parkinson's disease: a systematic review and meta-analysis.

BACKGROUND: Obstructive sleep apnea (OSA) is a common sleep disorder in Parkinson's disease (PD). However, the relationship between OSA and PD is still inconsistent. Our study was aimed to evaluate the relationship between PD and OSA. METHODS: Studies on OSA and PD were searched using PubMed, Embase, Web of Science, Cochrane library, and Chinese National Knowledge Infrastructure databases. Review Manager 5.3 software was used to calculate the pooled estimate effect. The inverse variance model was used to pool the mean difference (MD) or hazard ratios (HRs); the Mantel-Haenszel method was used to pool the odds ratio (OR). Heterogeneity among the studies was assessed using I2 statistic and Q test. RESULTS: A total of 12 studies with 93,332 cases were deemed eligible and included in our meta-analysis. Overall, the occurrence of PD was more frequent in patients with OSA (HR 1.59, 95% CI, 1.36-1.85). The subgroup analysis demonstrated the risk similarly by sex. Male and female had HR of incident PD with OSA of 1.56 (95% CI, 1.30-1.87) and 1.60 (95% CI, 1.21-2.11), respectively. The incidence of OSA did not increase in PD patients (OR 0.89, 95% CI, 0.53-1.49). The MD of apnea-hypopnea index (AHI) in PD patients was also not statistically significant (P = 0.5). CONCLUSIONS: The results indicate that OSA is one of independent risk factors of PD. However, OSA does not seem to be abnormally frequent in PD.

Characterization of a liquid-filled nodeless anti-resonant fiber for biochemical sensing.

We theoretically and experimentally characterize a liquid-filled nodeless anti-resonant fiber (LARF) that could find versatile applications in biochemical sensing. When a hollow-core nodeless anti-resonant fiber (HARF) is filled with a low refractive index liquid such as water or aqueous solutions in the whole hollow area, it preserves its anti-resonant reflection waveguiding mechanism with attributes encompassing the broad transmission bandwidth in UV, visible, and near IR; the neglectable confinement loss; and the acceptable single-mode quality. In comparison with other forms of hollow fiber, the moderate core size of our ARF allows both a large analyte-light overlap integral and a fast liquid flow rate. Such a LARF platform offers a promising route for creating compact, integrable and biocompatible all-fiber multifunctional optofluidic devices for in-situ applications. A proof-of-concept experiment of Raman spectroscopy using ethanol is presented, and applications in fluorescence spectroscopy, resonant Raman spectroscopy, noninvasive biochemical analysis, and interferometric sensing are in prospect.

Nodeless hollow-core fiber for the visible spectral range.

We report on a hollow-core fiber (HCF) whose fundamental transmission band covers almost the whole visible spectral window, starting at 440 nm. This HCF, in the form of a nodeless structure (NL-HCF), exhibits unprecedented optical performance in terms of low transmission attenuation of 80 dB/km at 532 nm, a broad transmission bandwidth from 440 to 1200 nm, a low bending loss of 0.2 dB/m at 532 nm under 8 cm bending radius, and single-mode profile. When launched to high-power picosecond laser systems at 532 nm, the fiber, exposed to ambient air, could easily deliver an 80 ps, 58 MHz, 32 W average power laser pulse with no damage and a 20 ps, 1 kHz high-energy laser pulse with a damage threshold in excess of 144 µJ at a fiber output. A proof-of-concept experiment on Raman spectroscopy in ambient air shows the significance of this broadband visible guiding HCF for interdisciplinary applications in nonlinear optics, ultrafast optics, lasers, spectroscopy, biophotonics, material processing, etc.

Bending loss characterization in nodeless hollow-core anti-resonant fiber.

We report high performance nodeless hollow-core anti-resonant fibers (HARFs) with broadband guidance from 850 nm to >1700 nm and transmission attenuation of ~100 dB/km. We systematically investigate their bending loss behaviors using both theoretical and experimental approaches. While a low bending loss value of 0.2 dB/m at 5 cm bending radius is attained in the long wavelength side (LWS) of the spectrum, in this paper, we pursue light guidance in the short wavelength side (SWS) under tight bending, which is yet to be explored. We analytically predict and experimentally verify a sub transmission band in the SWS with a broad bandwidth of 110 THz and an acceptable loss of 4.5 dB/m at 2 cm bending radius, indicating that light can be simultaneously guided in LWS and SWS even under tight bending condition. This provides an unprecedented degree of freedom to tailor the transmission spectrum under a tight bending state and opens new opportunities for HARFs to march into practical applications where broadband guidance under small bending radius is a prerequisite.

[Effects of antibiotic stewardship on neonatal bloodstream infections].

OBJECTIVE: To investigate the effects of antibiotic stewardship on the pathogen and clinical outcome of neonatal bloodstream infections (BSIs). METHODS: A retrospective study was performed on neonates with BSIs who were admitted to the neonatal ward in the years of 2010 (pre-stewardship) and 2013 (post-stewardship) for pathogens, antibiotic resistance, antibiotic use, and clinical outcomes. RESULTS: The admission rate of BSIs (6.47% vs 2.78%) and the incidence of nosocomial BSIs (0.70% vs 0.30%) in 2013 were significantly higher than in 2010 (P<0.01). However, there were no signicant differences in the clinical outcomes between the years of 2010 and 2013 (P>0.05). The four most common pathogens isolated from blood cultures, Staphylococcus haemolyticus, Staphylococcus epidermidis, Klebsiella pneumoniae ssp pneumoniae and E.coli, were similar between the two years. There were no significant differences in the detection rates of extended spectrum ß-lactamase-positve Klebsiella pneumoniae ssp pneumoniae or E.coli between the two years. The detection rates of methicillin-resistant Staphylococcus/ß-lactamase-positive Staphylococcus haemolyticus and Staphylococcus epidermidis were similar between the two years (P>0.05). CONCLUSIONS: Since the implementation of antibiotic stewardship, there has been no marked variation in the common pathogens and their antibacterial resistance in neonatal BSIs. The antibiotic stewardship could promote the recovery of patients with BSIs.

Rapid and sensitive detection of human astrovirus in water samples by loop-mediated isothermal amplification with hydroxynaphthol blue dye.

BACKGROUND: The aim of this paper was to develop a reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for rapid, sensitive and inexpensive detection of astrovirus. RESULTS: The detection limit of LAMP using in vitro RNA transcripts was 3.6 × 10 copies·µL⁻¹, which is as sensitive as the presently used PCR assays. However, the LAMP products could be identified as different colors with the naked eye following staining with hydroxynaphthol blue dye (HNB). No cross-reactivity with other gastroenteric viruses (rotavirus and norovirus) was observed, indicating the relatively high specificity of LAMP. The RT-LAMP method with HNB was used to effectively detect astrovirus in reclaimed water samples. CONCLUSIONS: The LAMP technique described in this study is a cheap, sensitive, specific and rapid method for the detection of astrovirus. The RT-LAMP method can be simply applied for the specific detection of astrovirus and has the potential to be utilized in the field as a screening test.

The surface protease ompT serves as Escherichia coli K1 adhesin in binding to human brain micro vascular endothelial cells.

Escherichia coli (E. coli) K1 is the most common bacteria that cause meningitis in the neonatal period. But it's not entirely clear about how E. coli crosses the blood-brain barrier. The features of the ompT deletion in meningitic E. coli infection were texted in vitro. In comparison with the parent strain, the isogenic ompT deletion mutant was significantly less adhesive to human brain microvascular endothelial cells (HBMEC). The adhesion-deficient phenotype of the mutant was restored to the level of the wild-type by complementing with low-level OmpT expression plasmid. Interestingly, the adhesion was enhanced by point mutation at the OmpT proposed catalytic residue D85. Compared with the poor adhesive activity of bovine serum albumin-coated fluorescent beads, recombinant OmpT or catalytically inactive variant of OmpT-coated beads bound to HBMEC monolayer effectively. Our study suggests that OmpT is important for bacterial adhesion while entering into central nervous system, and the adhesion does not involve in the proteolytic activity of OmpT.

Effects of probiotics on the growth performance and intestinal micro flora of broiler chickens.

Antibiotics have been used in poultry industry for decades to promote growth and protect animals from diseases, followed by various side effects. In efforts of searching for a better alternative, probiotic is of extensive attention. We investigated the effects of Bacillus subtitles, Rhodopseudomonas palustris, Candida utilis and Lactobacillus acidophilus as 0.1% (W/W) feed additives on broiler growth performance and intestinal microflora. The results showed the probiotics treatments significantly improved growth of broilers. Broilers supplemented with B. subtilis and L. acidophilus weighed 18.4% and 10.1% more than birds in control group at 42 days of age. Furthermore the feed conversion ratios of the birds in the two groups were also improved, decreasing 9.1% and 12.9%, respectively. Further study indicated a significant increase of cecal Lactobacilli concentration in briolers supplemented with probiotics, expecially in L. acidophilus treatment group. Meanwhile, the count of cecal Actinomyces in birds treated with probiotics was significantly lower compared with the control group. In conclusion, probiotics such as B. subtitles and L. acidophilus are good alternatives to antibiotics in promoting growth resulting from a beneficial modulation of the intestinal micro flora, which leads to increased efficiency of intestinal digestion in the host animal.

Meta-analysis reveals variations in microbial communities from diverse stony coral taxa at different geographical distances.

Coral-associated microbial communities play a vital role in underpinning the health and resilience of reef ecosystems. Previous studies have demonstrated that the microbial communities of corals are affected by multiple factors, mainly focusing on host species and geolocation. However, up-to-date, insight into how the coral microbiota is structured by vast geographic distance with rich taxa is deficient. In the present study, the coral microbiota in six stony coral species collected from the coastal area of three countries, including United States of America (USA), Australia and Fiji, was used for analysis. It was found that the geographic influence on the coral microbiota was stronger than the coral host influence, even though both were significant. Interestingly, the contribution of the deterministic process to bacterial community composition increased as geographical distance grew. A total of 65 differentially abundant features of functions in coral microbial communities were identified to be associated with three geolocations. While in the same coastal area of USA, the similar relationship of coral microbiota was consistent with the phylogenetic relationship of coral hosts. In contrast to the phylum Proteobacteria, which was most abundant in other coral species in USA, Cyanobacteria was the most abundant phylum in Orbicella faveolata. The above findings may help to better understand the multiple natural driving forces shaping the coral microbial community to contribute to defining the healthy baseline of the coral microbiome.

A converging reputation ranking iteration method via the eigenvector.

Ranking user reputation and object quality in online rating systems is of great significance for the construction of reputation systems. In this paper we put forward an iterative algorithm for ranking reputation and quality in terms of eigenvector, named EigenRank algorithm, where the user reputation and object quality interact and the user reputation converges to the eigenvector associated to the greatest eigenvalue of a certain matrix. In addition, we prove the convergence of EigenRank algorithm, and analyse the speed of convergence. Meanwhile, the experimental results for the synthetic networks show that the AUC values and Kendall's τ of the EigenRank algorithm are greater than the ones from the IBeta method and Vote Aggregation method with different proportions of random/malicious ratings. The results for the empirical networks show that the EigenRank algorithm performs better in accuracy and robustness compared to the IBeta method and Vote Aggregation method in the random and malicious rating attack cases. This work provides an expectable ranking algorithm for the online user reputation identification.

Mesenchymal Stem Cells Improve Cognitive Impairment and Reduce Aß Deposition via Promoting AQP4 Polarity and Relieving Neuroinflammation in Rats With Chronic Hypertension-Induced Cerebral Small-Vessel Disease.

Cerebral small-vessel disease (CSVD) is the main cause of vascular cognitive impairment (VCI), and the accumulation of amyloid ß-protein (Aß) may be significantly involved in CSVD-induced VCI. The imbalance between Aß production and clearance is believed to be an important pathological mechanism of Aß deposition in Alzheimer disease. In this study, we aimed to disclose the roles of aquaporin 4 (AQP4) and neuroinflammation in CSVD, which were the key factors for Aß clearance and production, respectively, and the effect of mesenchymal stem cells (MSCs) on Aß deposition and these two factors. The stroke-prone renovascular hypertensive (RHRSP) rats were grouped and received MSC and MSC + AS1517499 (an inhibitor of pSTAT6). The latter was used to explore the underlying mechanism. The cognitive function, white matter lesions, Aß expression, expression, and polarity of AQP4, neuroinflammation and the STAT6 pathway were investigated. Compared with sham-operated rats, RHRSP rats showed spatial cognitive impairment, white matter lesions and Aß deposition. Moreover, AQP4 polarity disorder and neuroinflammatory activation were found, which were linked to Aß deposition. Treatment with MSCs markedly improved cognitive tasks and reduced Aß deposition but failed to reduce white-matter lesions. Furthermore, MSCs not only promoted AQP4 polarity but also alleviated neuroinflammation probably through the STAT6 pathway. The present study demonstrated that Aß deposition, AQP4 polarity disorder and neuroinflammation might be involved in CSVD and the regulatory effects of MSCs on them suggested potential therapeutic value for CSVD.

Identifying the Dominant Role of Pyridinic-N-Mo Bonding in Synergistic Electrocatalysis for Ambient Nitrogen Reduction.

For electrochemical nitrogen reduction reaction (NRR), hybridizing transition metal (TM) compounds with nitrogen-doped carbonaceous materials has been recognized as a promising strategy to improve the activity and stability of electrocatalysts due to the synergistic interaction from the TM-N-C active sites. Nevertheless, up to date, the fundamental mechanism of this so-called synergistic electrocatalysis for NRR is still unclear. Particularly, it remains ambiguous which configuration of N dopants, either pyridinic N or pyrrolic N, when coordinated with the TM, predominately contributes to this synergy. Herein, a self-assembled three-dimensional 1T-phase MoS2 microsphere coupled with N-doped carbon was developed (termed MoS2/NC), showing an impressive NRR performance in neutral medium. The hybridization of MoS2 and N-doped carbon can synergistically enhance the NRR efficiency by optimizing the electron transfer of catalyst. Acidification/blocking/poisoning experiments reveal the decisive role of pyridinic-N-Mo bonding, rather than pyrrolic-N-Mo bonding, in synergistically enhancing NRR electrocatalysis. The electrochemical-based in situ Fourier transform infrared spectroscopy (in situ FTIR) technology provides deep insights into the substantial contribution of pyridinic-N-MoS2 sites to NRR electrocatalysis and further uncover the underlying mechanism (associative pathway) at a molecular level.

Tetrandrine inhibits proliferation of colon cancer cells by BMP9/ PTEN/ PI3K/AKT signaling.

Despite advances in screening and treatment, colon cancer remains one of the leading causes of cancer-related death. Finding novel and useful drug treatment targets is also an urgent need for clinical applications. Tetrandrine (Tet) is extracted from the Chinese medicinal herbal medicine, which is a well-known calcium blocker with a variety of pharmacological activities, including anti-cancer. In this study, we recruited cell viability assay, flow cytometry analysis, cloning formation to confirm that Tet can inhibit the proliferation of SW620 cells, and induce apoptosis. Mechanically, we confirmed that Tet up-regulates the mRNA and protein level of BMP9 in SW620 cells. Over-expression BMP9 enhances the anti-cancer effects of Tet in SW620 cells, but these effects can be partly reversed by silencing BMP9. Also, Tet reduces phosphorylation of Aktl/2/3 in SW620 cells, which could be elevated by overexpressed BMP9 and impaired by silencing BMP9. Furthermore, we demonstrated that Tet reduces phosphorylated PTEN, which can be promoted by overexpressed BMP9, analogously also be attenuated through silencing BMP9. Finally, we introduced a xenograft tumor model to investigate the anti-proliferative effect of Tet, further to explore the effects of BMP9 and PTEN in SW620 cells. Our findings suggested that the anti-cancer activity of Tet in SW620 cells may be mediated partly by up-regulating BMP9, followed by inactivation PI3K/Akt through up-regulating PTEN at least.

Anti­proliferative effect of honokiol on SW620 cells through upregulating BMP7 expression via the TGF­ß1/p53 signaling pathway.

Honokiol (HNK), a natural pharmaceutically active component extracted from magnolia bark, has been used for clinical treatments and has anti­inflammatory, antiviral and antioxidative effects. In recent years, anticancer research has become a major hotspot. However, the underlying molecular mechanisms of how HNK inhibits colorectal cancer have remained elusive. The present study focused on elucidating the effects of HNK on the expression of bone morphogenetic protein (BMP)7 and its downstream interaction with transforming growth factor (TGF)­ß1 and p53 in colon cancer. In in vitro assays, cell viability, cell cycle distribution and apoptosis were examined using Cell Counting Kit­8, flow cytometry and reverse transcription­quantitative PCR, respectively. In addition, the expression of BMP7, TGF­ß1 and relevant signaling proteins was determined by western blot analysis. In vivo, the anticancer effect of HNK was assessed in xenografts in nude mice. Furthermore, immunohistochemistry was performed to evaluate the association between BMP7 and TGF­ß1 expression in colon cancer. The results indicated that HNK inhibited the proliferation of colon cancer cell lines, with SW620 cells being more sensitive than other colon cancer cell lines. Furthermore, HNK markedly promoted the expression of BMP7 at the mRNA and protein level. Exogenous BMP7 potentiated the effect of HNK on SW620 cells, while knocking down BMP7 inhibited it. As a downstream mechanism, HNK increased the expression of TGF­ß1 and p53, which was enhanced by exogenous BMP7 in SW620 cells. In addition, immunohistochemical analysis indicated a positive association between BMP7 and TGF­ß1 expression. Hence, the present results suggested that HNK is a promising agent for the treatment of colon cancer and enhanced the expression TGF­ß1 and p53 through stimulating BMP7 activity via the non­canonical TGF­ß signaling pathway.

Electroacupuncture ameliorates cerebral ischemia/reperfusion injury by suppressing autophagy via the SIRT1-FOXO1 signaling pathway.

Cerebral ischemia/reperfusion (CIR) injury occurs when blood flow is restored in the brain, causing secondary damage to the ischemic tissues. Previous studies have shown that electroacupuncture (EA) treatment contributes to brain protection against CIR injury through modulating autophagy. Studies indicated that SIRT1-FOXO1 plays a crucial role in regulating autophagy. Here we investigated the mechanisms underlying the neuroprotective effect of EA and its role in modulating autophagy via the SIRT1-FOXO1 signaling pathway in rats with CIR injury. EA pretreatment at "Baihui", "Quchi" and "Zusanli" acupoints (2/15Hz, 1mA, 30 min/day) was performed for 5 days before the rats were subjected to middle cerebral artery occlusion, and the results indicated that EA pretreatment substantially reduced the Longa score and infarct volume, increased the dendritic spine density and lessened autophagosomes in the peri-ischemic cortex of rats. Additionally, EA pretreatment also reduced the ratio of LC3-II/LC3-I, the levels of Ac-FOXO1 and Atg7, and the interaction of Ac-FOXO1 and Atg7, but increased the levels of p62, SIRT1, and FOXO1. The above effects were abrogated by the SIRT1 inhibitor EX527. Thus, we presume that EA pretreatment elicits a neuroprotective effect against CIR injury, potentially by suppressing autophagy via activating the SIRT1-FOXO1 signaling pathway.

Correction to: Better survival in female SOD1-mutant patients with ALS: a study of SOD1-related natural history.

[This corrects the article DOI: 10.1186/s40035-018-0142-8.].

Better survival in female SOD1-mutant patients with ALS: a study of SOD1-related natural history.

BACKGROUND: SOD1 mutations are the most common cause of amyotrophic lateral sclerosis (ALS) in non-Caucasian patients. Detailed natural history profiles of SOD1-mutant patients will be beneficial for the strategy and interpretation of future SOD1-targeted clinical practice. METHODS: Mutational distribution, age at onset (AAO), site of onset, diagnostic delay, disease progression (rate of ALSFRS-R decrease, ΔFS) and survival were analysed. Further comparisons between heredity of disease, gender, and mutations were performed. RESULTS: Sixty-six cases with 43 SOD1 mutations were included and analysed, with p.His47Arg as the leading mutation and seven novel variants identified. The mean (SD) AAO was 43.92 years (9.24) for all subjects, with a significant difference between patients carrying mutations in exon 2 (n = 24,46.83, 8.31) and exon 4 (n = 18, 37.75, 7.67) (p = 0.002). The median (IQR) diagnostic delay from symptom onset was 14.50 (6.00-36.50) months for all SOD1-mutant patients, 9.50 (4.75-24.25) months for males and 24.00 (9.50-47.50) months for females, revealing a gender difference (p = 0.009). Similar advantages in median (IQR) ΔFS [male: female, 0.55 (0.24-0.94) vs 0.19 (0.06-0.90), p = 0.041] and mean (95% CI) survival [57.4 (38.90-75.90) months vs 125.6 (99.80-151.50) months, p = 0.006] were also observed in females, both of which existed in sporadic ALS only when stratified by familiar or sporadic ALS. CONCLUSIONS: The results highlight a distinct mutational distribution and natural history spectrum in ALS patients carrying SOD1 mutations in China. A prominent mild disease progression was observed in female patients, which had rarely been reported in the previous literature. This finding, together with the detailed analysis of natural history among each mutation, can have important implications for future genetic counselling and SOD1-targeted clinical trials.

Prognostic factors in ALS: a comparison between Germany and China.

OBJECTIVE: Several independent prognostic factors, such as age of onset, type of onset, body mass index (BMI), and progression rate have been identified for amyotrophic lateral sclerosis (ALS) in Caucasians. The aim of this study was to identify such factors in Chinese patients and to compare their impact with German patients. METHODS: Comparison of prognostic factors was based on two hospital-based registries. The registry of the German Network for Motor Neuron Diseases contains 3100 patients with ALS. The Chinese registry comprises 2101 patients who were collected between 2003 and 2015 in the metropolitan area of Beijing. RESULTS: Disease progression was slower in China [median loss of 0.50 points (IQR 0.26-0.87 points) versus 0.55 points (IQR 0.28-1.00 points) of ALS functional rating scale revised (ALS-FRS-R) score per month; p < 0.0001]. Survival of patients with ALS was similar in Germany and China (p > 0.05). We found that younger age of onset (p < 0.0001), spinal onset (p < 0.0001), high BMI (p < 0.0001) and low progression rate (p < 0.0001) were positive prognostic factors in China as well as in Germany. INTERPRETATION: Prognostic factors, which are known to modify the course of disease in Caucasians, apply to Chinese patients as well. The results indicate that despite the apparent differences regarding genotype and clinical phenotype, findings from interventional studies in Caucasians aiming at disease-modifying prognostic factors (such as body weight) may be transferred to Chinese patients.

Comparison of three-way and four-way calibration for the real-time quantitative analysis of drug hydrolysis in complex dynamic samples by excitation-emission matrix fluorescence.

Multiway calibration in combination with spectroscopic technique is an attractive tool for online or real-time monitoring of target analyte(s) in complex samples. However, how to choose a suitable multiway calibration method for the resolution of spectroscopic-kinetic data is a troubling problem in practical application. In this work, for the first time, three-way and four-way fluorescence-kinetic data arrays were generated during the real-time monitoring of the hydrolysis of irinotecan (CPT-11) in human plasma by excitation-emission matrix fluorescence. Alternating normalization-weighted error (ANWE) and alternating penalty trilinear decomposition (APTLD) were used as three-way calibration for the decomposition of the three-way kinetic data array, whereas alternating weighted residual constraint quadrilinear decomposition (AWRCQLD) and alternating penalty quadrilinear decomposition (APQLD) were applied as four-way calibration to the four-way kinetic data array. The quantitative results of the two kinds of calibration models were fully compared from the perspective of predicted real-time concentrations, spiked recoveries of initial concentration, and analytical figures of merit. The comparison study demonstrated that both three-way and four-way calibration models could achieve real-time quantitative analysis of the hydrolysis of CPT-11 in human plasma under certain conditions. However, it was also found that both of them possess some critical advantages and shortcomings during the process of dynamic analysis. The conclusions obtained in this paper can provide some helpful guidance for the reasonable selection of multiway calibration models to achieve the real-time quantitative analysis of target analyte(s) in complex dynamic systems.