Search

A novel moderately thermophilic heterotrophic bacterium, designated strain 143-21T, was isolated from a deep-sea hydrothermal chimney sample collected from the Central Indian Ridge at a depth of 2 440 m. Phylogenetic analysis indicated that strain 143-21T belongs to the genus Crassaminicella . It was most closely related to Crassaminicella thermophila SY095T (96.79 % 16S rRNA gene sequence similarity) and Crassaminicella profunda Ra1766HT (96.52 %). Genomic analysis showed that strain 143-21T shares 79.79–84.45 % average nucleotide identity and 23.50–29.20 % digital DNA–DNA hybridization with the species of the genus Crassaminicella , respectively. Cells were rod-shaped, non-motile, Gram-positive-staining. Terminal endospores were observed in stationary-phase cells when strain 143-21T was grown on Thermococcales rich medium. Strain 143-21T was able to grow at 30–60 °C (optimum, 50 °C), pH 6.5–8.5 (optimum, pH 7.0) and in 1.0–7.0 % NaCl (w/v; optimum 2.0 %, w/v). Strain 143-21T utilized fructose, glucose, maltose, mannose, ribose, N-acetyl-d-(+)-glucosamine and casamino acids, as well as amino acids including glutamate, lysine, histidine and cysteine. The main fermentation products from glucose were acetate (2.07 mM), H2 and CO2. It did not reduce elemental sulphur, sulphate, thiosulphate, sulphite, fumarate, nitrate, nitrite and Fe (III). The predominant cellular fatty acids were C14 : 0 (48.8 %), C16 : 0 (12.9 %), and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c; 10.2 %). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol, as well as two unidentified phospholipids and four unidentified aminolipids. No respiratory quinones were detected. Based on its phylogenetic analysis and physiological characteristics, strain 143-21T is considered to represent a novel species of the genus Crassaminicella , for which the name Crassaminicella indica sp. nov. is proposed. The type strain is strain 143-21T (=DSM 114408T= MCCC 1K06400T).

In this article, a novel p-GaN high-electron-mobility transistor (HEMT) with a built-in Schottky barrier diode (SBD) is proposed and investigated by TCAD simulation. The anode contact of the integrated SBD is isolated from the ohmic contact of the source electrode by a p-GaN isolation region. The cathode of the SBD is connected to the drain electrode. In the proposed Schottky barrier diode/HEMT (SB-HEMT), a channel under the p-GaN isolation region is turned on during forward conduction to further reduce the specific on-resistance ( $R_{{on},sp}$ ). With a minimum sacrifice on $R_{{on},sp}$ , the reverse on-state voltage, $V_{R-{on}}$ (at a current density of 50 mA/mm), for the SB-HEMT is reduced by 33% (from 2.43 to 1.62 V) when compared with a conventional HEMT (C-HEMT). Compared with the C-HEMT with a separate on-chip SBD (C-HEMT/SBD), the SB-HEMT shows much better trade-off between $V_{R-{on}}$ and $R_{{on},sp}$ . The total switching loss ( $E_{total}$ ) of the proposed SB-HEMT with resistive load is lower than that of the C-HEMT and is reduced by up to 21% when compared with that of the C-HEMT/SBD with different area ratio between the HEMT and SBD regions.

Conventional di/dt and dv / dt control and gate protection techniques for gallium nitride (GaN) power transistors usually employ external controllers, isolation circuits, discrete pull-up, and pull-down resistors. With large number of components, power modules become more complex and may introduce additional parasitic. Gate driver ICs with segmented output stages and dynamic gate driving have been reported previously to be effective in simultaneously suppressing gate ringing and overshoot voltage while maintaining fast switching speed. However, the programming for dynamic gate driving is rather complicated, requiring the user to load a sequence of driving patterns obtained from trial and error ahead of time. This article presents a gate driver IC for E-mode GaN power transistors with seven segmented output stages. More importantly, it offers a simplified programming method for the dynamic gate driving pattern. The optimal gate drive pattern can be defined by simply adjusting one external bias resistor. The proposed method eliminates the complex trial and error digital control, and can potentially promoting the wider acceptance of dynamic gate driving by the industry. The timing resolution for the gate drive pattern can be varied in steps from 0.5 to 5 ns. It can also be used to drive many commercially available GaN power transistors.

BackgroundNeuropsychiatric symptoms (NPSs) belong to a category of non-motor symptoms of Parkinson's disease (PD), which seriously compromise the quality of life and prognosis of PD. This study focused on the correlations between NPSs, free radicals, neuroinflammatory factors, and neuropathological proteins in cerebrospinal fluid (CSF) in patients with PD, aiming to provide insights into the potential mechanisms and therapeutic target for PD with NPSs (PD-NPSs).MethodsIn total, 129 patients with PD were enrolled and assessed by the Neuropsychiatric Symptoms Inventory (NPI); they were divided into the PD-NPSs group (75 patients) and PD with no NPSs (PD-nNPSs) group (54 patients). The levels of hydrogen peroxide (H2O2) and nitric oxide (NO), and hydroxyl radical (·OH), anti-oxidative enzyme, neuroinflammatory factors, and neuropathological proteins in CSF from patients with PD were measured. The levels of the above variables were compared between PD-NPSs and PD-nNPSs groups, and correlation analyses among the above variables were conducted.Results(1) The levels of H2O2 and NO in CSF from the PD-NPSs group were significantly elevated compared with the PD-nNPSs group (p = 0.001), and NPI score positively correlated with the levels of H2O2 and NO (r = 0.283, P = 0.001; r = 0.231, P = 0.008). Reversely, total superoxide dismutase (tSOD) activity in CSF from the PD-NPSs group was significantly reduced compared with the PD-nNPSs group (p = 0.011), and negatively correlated with NPI score (r = −0.185, p = 0.036). (2) The tumor necrosis factor (TNF)-α level in CSF from the PD-NPSs group was significantly decreased compared with the PD-nNPSs group (p = 0.002) and negatively correlated with NPI score (r = −0.211, p = 0.016). (3) The total tau (T-tau) level in CSF from the PD-NPSs group was significantly higher than in the PD-nNPSs group (p = 0.014) and positively correlated with the NPI score (r = 0.167, p = 0.060). (4) The levels of H2O2 and NO positively correlated with the T-tau level in CSF from the PD-NPSs group (r = 0.183, p = 0.039; r = 0.251, P = 0.004), and the levels of TNF-α and T-tau showed a negative correlation (r = −0.163, p = 0.067).ConclusionOxidative distress characterized by the elevations of H2O2 and NO levels may closely correlate with the neurodegeneration in brain regions related to PD-NPSs. Thus, therapeutic antioxidants may become an important target for PD-NPSs therapy.

Endosomal sorting complex required transport (ESCRT) III proteins are essential for membrane remodeling and repair across all domains of life. Eukaryotic ESCRT-III and the cyanobacterial homologs PspA and Vipp1/Imm30 remodel membrane into vesicles, rings, filaments and tubular rods structures. Here our microscopy analysis showed that multicellular bacteria, referred to as magnetoglobules, possess multiple compartments including magnetosome organelles, polyphosphate granules, vesicles, rings, tubular rods, filaments and MVB-like structures. Therefore, membrane remodeling protein PspA might be required for the formation of these compartments, and contribute to the morphogenesis and evolution of multicellularity. To assess these hypotheses, we sequenced nine genomes of magnetoglobules and found a significant genome expansion compared to unicellular magnetotactic bacteria. Moreover, PspA was ubiquitous in magnetoglobules and formed a distinct clade on the tree of eubacterial and archaeal ESCRT-III. The phylogenetic feature suggested the evolution of magnetoglobules from a unicellular ancestor of deltaproteobacterium. Hetero-expression of ellipsoidal magnetoglobulepspA2gene alone inEscherichia coliresulted in intracellular membrane aggregation. GFP fusion labeling revealed polar location of PspA2 in rod-shaped unicells and regular interval location in filamentous cells. Cryo-electron tomography analysis showed filament bundle, membrane sacculus, vesicles and MVB-like structure in the cells expressing PspA2. Moreover, electron-dense area with a similar distribution as GFP-PspA2 foci in filamentous cells changed the inward orientation of the septum, which might interfere with the cell division. Collectively, these results show the membrane remodeling function of magnetoglobule PspA proteins, which may contribute to morphogenesis and the evolution of multicellularity of magnetotactic bacteria.

In this paper, in order to investigate the size effect on the flexural behavior of ultra-high-performance concrete (UHPC) beams, two groups UHPC beams with sizes of, (small) and (large), were tested through four-point bending test. Each group consists of four UHPC beams with different rebar type and reinforcement ratio. The experimental results showed that the flexural strength, normalized deflection, and fracture toughness of HRB400 steel reinforced UHPC beams was not affected by size effect. The normalized deflection at ultimate bearing capacity of GFRP reinforced UHPC beams is affected by size effect, but no size effect was shown for whole deflection process. The flexural strength and fracture toughness of GFRP reinforced UHPC beams changed from having size effect to no size effect with the increase of reinforcement ratio. Furthermore, the maximum crack width, number of cracks and average crack spacing of both UHPC beams were sensitive to the size of specimen, while no significant size effect was shown for ductility of both UHPC beams.

A miniaturized atomic spin-exchange relaxation-free (SERF) co-magnetometer measures angular velocity using a balanced polarimetry technique which is easily affected by the laser power. A laser power closed-loop control system is usually used to suppress the fluctuation of the laser power. Although this method can greatly eliminate the fluctuation of the in-loop laser power (the feedback laser), it cannot fully eliminate the fluctuation of the out-of-loop laser power (the signal measurement laser). This leads to SERF gyroscope laser power error, which reduces the inertial measurement accuracy. In this paper, the influence mechanism of the split ratio (the ratio of the in-loop laser power to the out-of-loop laser power) on the out-of-loop laser power control accuracy is analyzed by establishing a laser power transmission model inside and outside the loop. Moreover, a method is developed to improve the out-of-loop laser power stability by optimizing the split ratio. Comparative experiments showed that the relative Allan standard deviation of the out-of-loop laser power decreased from 5.48 × 10−6 to 2.62 × 10−6 at 100 s, and decreased by an order of magnitude from 1.76 × 10−5 to 3.30 × 10−6 at 1000 s. Correspondingly, the rate ramp coefficient in the Allan standard deviation curve of the SERF gyroscope test data decreased from 1.312 [(°/h)/h] to 0.246 [(°/h)/h]. And the bias stability increased from 0.032 °/h to 0.019 °/h. Therefore, the proposed method can improve the long-term stability of the probe laser power and effectively suppress the laser power error of the SERF gyroscope.

Deep-sea hydrothermal vents are known as chemosynthetic ecosystems. However, high temperature vents emit light that hypothetically can drive photosynthesis in this habitat. Metagenomic studies have sporadically reported the occurrence of phototrophic populations such as cyanobacteria in hydrothermal vents. To determine how geographically and taxonomically widespread phototrophs are in deep-sea hydrothermal vents, we collected samples from three niches in a hydrothermal vent on the Southwest Indian Ridge and carried out an integrated metagenomic analysis. We determined the typical community structures of microorganisms found in active venting fields and identified populations of known potential chlorophototrophs and retinalophototrophs. Complete chlorophyll biosynthetic pathways were identified in all samples. By contrast, proteorhodopsins were only found in active beehive smoker diffusers. Taxonomic groups possessing potential phototrophy dependent on semiconductors present in hydrothermal vents were also found in these samples. This systematic comparative metagenomic study reveals the widespread distribution of phototrophic bacteria in hydrothermal vent fields. Our results support the hypothesis that the ocean is a seed bank of diverse microorganisms. Geothermal vent light may provide energy and confer a competitive advantage on phototrophs to proliferate in hydrothermal vent ecosystems. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42995-021-00121-y.

A novel moderately thermophilic, anaerobic, heterotrophic bacterium (strain SY095T) was isolated from a hydrothermal vent chimney located on the Southwest Indian Ridge at a depth of 2730 m. Cells were Gram-stain-positive, motile, straight to slightly curved rods forming terminal endospores. SY095T was grown at 45–60 °C (optimum 50–55 °C), pH 6.0–7.5 (optimum 7.0), and in a salinity of 1–4.5 % (w/v) NaCl (optimum 2.5 %). Substrates utilized by SY095T included fructose, glucose, maltose, N-acetyl glucosamine and tryptone. Casamino acid and amino acids (glutamate, glutamine, lysine, methionine, serine and histidine) were also utilized. The main end products from glucose fermentation were acetate, H2 and CO2. Elemental sulphur, sulphate, thiosulphate, sulphite, fumarate, nitrate, nitrite and Fe(III) were not used as terminal electron acceptors. The predominant cellular fatty acids were C14 : 0 (60.5%) and C16 : 0 (7.6 %). The main polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, five unidentified phospholipids and two unidentified aminophospholipids. No respiratory quinones were detected. The chromosomal DNA G+C content was 30.8 mol%. The results of phylogenetic analysis of the 16S rRNA gene sequences indicated that SY095T was closely related to Crassaminicella profunda Ra1766HT (95.8 % 16S rRNA gene sequence identity). SY095T exhibited 78.1 % average nucleotide identity (ANI) to C. profunda Ra1766HT. The in silico DNA–DNA hybridization (DDH) value indicated that SY095T shared 22.7 % DNA relatedness with C. profunda Ra1766HT. On the basis of its phenotypic, genotypic and phylogenetic characteristics, SY095T is suggested to represent a novel species of the genus Crassaminicella , for which the name Crassaminicella thermophila sp. nov. is proposed. The type strain is SY095T (=JCM 34213=MCCC 1K04191). An emended description of the genus Crassaminicella is also proposed.

At high altitude, wastewater aeration efficiency is low, which is detrimental to nitrification in conventional biological nitrogen removal. The combined partial nitritation and anaerobic ammonium oxidation (CPNA) process requires little oxygen and can be appropriate in low-pressure conditions. As such, in this study, we investigated the effect of air pressure on CPNA using a laboratory-scale reactor. We found that low air pressure promoted the removal of total inorganic nitrogen (TIN), achieving a TIN removal rate of 43,000 mg·N/(kg·VSS·d). The secretion of extracellular polymeric substances under low air pressure was not significantly different from that under ordinary air pressure, indicating no adverse effects on microbial aggregation ability, stability, or settleability. The abundance of aerobic ammonia-oxidizing bacteria (AeAOB) increased from 0.2% to 5.6%, and the activity of anaerobic ammonia-oxidizing bacteria (AnAOB) enhanced, giving AeAOB and AnAOB a competitive advantage over nitrite-oxidizing bacteria, thus forming a microbial community structure favorable to the CPNA process. Our further analysis of the results of batch tests in serum bottles confirmed the positive effect of low air pressure on the anaerobic ammonium oxidation (anammox) process, with a 28.5% ± 1.9% improvement in the specific anammox rate at 70 kPa compared with 100 kPa. AnAOB activity increased, which was reflected in the intracellular heme content increasing from 0.56 ± 0.18 μmol/(g·VSS) at 100 kPa to 2.56 ± 0.20 μmol/(g·VSS) at 70 kPa. We clarified the CPNA-process-promoting effect of low air pressure, which shows potential for nitrogen removal in high-altitude regions.

Ethnopharmacological relevance Canarium album Raeusch. belongs to the Burseraceae family. Its ripe fruits, known as Qing Guo (QG) in Traditional Chinese Medicine (TCM), are used to treat sore throat, cough, and fish or crab poisoning. QG was reported to have antibacterial activity, and it exerted excellent anti-Helicobacter pylori (H. pylori) activity in our screening of abundant TCM. However, few studies have reported its anti-H. pylori activity and mechanism. Aim of study The commonly used eradication therapies for H. pylori infection are antibiotic-based therapies. With the increasing antibiotic resistance of H. pylori, interest in finding alternative therapies has been aroused. This study investigated the phytochemistry profile, in vitro anti-H. pylori activity and possible anti-bacterial mechanism of QG extracts. Materials and methods QG extracts were obtained by heat reflux extraction, ultrasonic extraction or liquid-liquid extraction with different solvents. The quantitative and qualitative phytochemical analyses were performed by colorimetric determination, high-performance liquid chromatography (HPLC), and UPLC-electrospray ionization mass spectrometry (ESI-MS). In vitro anti- H. pylori activity was assessed by broth micro-dilution method. Mechanism of action studies included morphological observation using electron microscopy, urease inhibition assay and determination of expression of virulence genes by RT-qPCR. Results All QG extracts especially ethyl acetate extract (QGEAE) were rich in phenolic components, with the minimum inhibitory concentrations (MICs) on H. pylori of 39–625 μg/ml and minimum bactericidal concentrations (MBCs) of 78–1250 μg/ml. Both aqueous extract (QGAE) and QGEAE could induce the morphological and structural changes of H. pylori, inhibit urease activity with IC50 of 1093 μg/ml and 332.90 μg/ml, respectively, and down-regulate the virulence genes, such as vacA and cagA. Conclusions QG may exhibit in vitro anti-H. pylori activity by inhibiting growth, destroying the bacterial structure and down-regulating the expression of virulence factors. Moreover, QG is the homology of food and TCM, which can be considered as a safe and convenient agent against H. pylori infection.