Characterization and application of Bacillus velezensis D6 co-producing α-amylase and protease.

BACKGROUND: Research on the co-production of multiple enzymes by Bacillus velezensis as a novel species is still a topic that needs to be studied. This study aimed to investigate the fermentation characteristics of B. velezensis D6 co-producing α-amylase and protease and to explore their enzymatic properties and applications in fermentation. RESULTS: The maximum co-production of α-amylase and protease reached 13.13 ± 0.72 and 2106.63 ± 64.42 U mL-1, respectively, under the optimal fermented conditions (nutrients: 20.0 g L-1 urea, 20.0 g L-1 glucose, 0.7 g L-1 MnCl2; incubation conditions: initial pH 7.0, temperature 41 °C, 8% inoculation size and 30% working volume). Moreover, the genetic co-expression of α-amylase and protease increased from 0 to 24 h and then decreased after 36 h at the transcriptional level, which coincided with the growth trend of B. velezensis D6. The optimal reaction temperature of α-amylase was 55-60 °C, while that of protease was 35-40 °C. The activities of α-amylase and protease were retained by over 80% after thermal treatment (90 °C, 1 h), which indicated that two enzymes co-produced by B. velezensis D6 demonstrated excellent thermal stability. Moreover, the two enzymes were stable over a wide pH range (pH 4.0-8.0 for α-amylase; pH 4.0-9.0 for protease). Finally, the degrees of hydrolysis of corn, rice, sorghum and soybeans by α-amylase from B. velezensis D6 reached 44.95 ± 2.95%, 57.16 ± 2.75%, 52.53 ± 4.01% and 20.53 ± 2.42%, respectively, suggesting an excellent hydrolysis effect on starchy raw materials. The hydrolysis degrees of mackerel heads and soybeans by protease were 43.93 ± 2.19% and 26.38 ± 1.72%, respectively, which suggested that the protease from B. velezensis D6 preferentially hydrolyzed animal-based protein. CONCLUSION: This is a systematic study on the co-production of α-amylase and protease by B. velezensis D6, which is crucial in widening the understanding of this species co-producing multi-enzymes and in exploring its potential application. © 2024 Society of Chemical Industry.

Photonic convolutional neural network with robustness against wavelength deviations.

We experimentally explore the practicality of integrated multiwavelength laser arrays (MLAs) for photonic convolutional neural network (PCNN). MLAs represent excellent performance for PCNN, except for imperfect wavelength spacings due to fabrication variation. Therefore, the performance of PCNN with non-ideal wavelength spacing is investigated experimentally and numerically for the first time. The results show that there exists a certain tolerance for wavelength deviation on the degradation of the structural information of the extracted feature map, leading to the robustness of photonic recognition accuracy under non-ideal wavelength spacing. The results suggest that scalable MLAs could serve as an alternative source for the PCNN, to support low-cost optical computing scenarios. For a benchmark classification task of MNIST handwritten digits, the photonic prediction accuracy of 91.2% for stride 1 × 1 scheme using the testing dataset are experimentally obtained at speeds on the order of tera operations per second, compared to 94.14% on computer. The robust performance, flexible spectral control, low cost, large bandwidth and parallel processing capability of the PCNN driven by scalable MLAs may broaden the application possibilities of photonic neural networks in next generation data computing applications.

Numerical modeling of submicron particles for acoustic concentration in gaseous flow.

This paper intends to explore the rationality and feasibility of modeling dispersed submicron particles in air by a kinetic-based method called the unified gas-kinetic scheme (UGKS) and apply it to the simulation of particle concentration under a transverse standing wave. A gas-particle coupling scheme is proposed where the gas phase is modeled by the two-dimensional linearized Euler equations (LEE) and, through the analogous behavior between the rarefied gas molecules and the air-suspended particles, a modified UGKS is adopted to estimate the particle dynamics. The Stokes' drag force and the acoustic radiation force applied on particles are accounted for by introducing a velocity-dependent acceleration term in the UGKS formulation. To validate this methodology, the computed concentration patterns are compared with experimental results in the literature. The comparison shows that the adopted LEE-UGKS coupling scheme could well capture the concentration pattern of suspended submicron particles in a channel. In addition, numerical simulations with varying standing wave amplitudes, different acoustic radiation force to drag force ratios, and mean flow velocities are conducted. Their respective influences on the particle concentration pattern and efficiency are analyzed.

One-dimensional parallax-free position-sensitive detector for diffraction measurements based on a home-made thin THGEM.

A large parallax-free gas diffraction meter based on a thinner-THGEM (thick gaseous electron multiplier) has been developed at the Beijing Synchrotron Radiation Facility (BSRF). A thinner-THGEM of thickness 200 µm is adopted, which can be shaped into a curve to eliminate parallax-error effects. The detector is designed to have a 48° open angle positioned 20 cm from the powder samples. A front-end electronics board with 128 channels direct-current mode was adapted for the 8 keV BSRF beamline with 0.2 ns/100 ns stable duty cycle. Two powder samples, TiO2 and SnO2, were tested separately. The measured spectra with an angular resolution of 0.148 ± 0.081° are consistent with the data from the powder diffraction file. Combining the gas gain of the thinner-THGEM with the electronic circuit dynamic range, a very broad dynamic range of about 107 could be obtained.

Breaking Through the Signal-to-Background Limit of Upconversion Nanoprobes Using a Target-Modulated Sensitizing Switch.

Although lanthanide-doped upconversion nanoparticles (UCNPs) have shown great promise in biosensing and bioimaging owing to their excellent photophysical properties, researchers are facing a bottleneck of upconversion (UC) probes which is the limited signal-to-background ratio (SBR). Since UC nanoprobes are basically constructed with a luminescence resonance energy transfer (LRET) process to provide "off-on" signals, the SBR level is principally decided by the luminescence quenching efficiency which is very difficult to further improve through existing approaches. Herein, we put forward a new strategy for fabricating UC nanoprobes using an organic dye as target-modulated sensitizing switch. The dye functions as both the recognition unit for target and a potential sensitizer for upconversion luminescence (UCL). The reaction of the dye with target modulates its photophysical properties, which switches on the sensitization and affords a significantly improved SBR. The idea is validated with a proof-of-concept UC nanoprobe for glutathione (GSH) detection with the SBR of ∼30 (versus a SBR of less than 10 for most current UC nanoprobes). This probe showed good performance in GSH sensing both in vitro and in vivo. Our results indicate that the target-modulated sensitization is a useful new strategy to build UC nanoprobes. And we can reasonably expect that the breakthrough of SBR limit will make UC nanoprobe a more powerful tool in future studies.

Hypothyroidism and sinus dysfunction associated with lithium-paliperidone combination therapy for bipolar disorder with psychotic symptoms: a case report.

Background and aim: Lithium is considered to be the first-line treatment for bipolar disorder, and paliperidone was approved for the treatment of schizophrenia and acute bipolar manic/mixed episodes. However, both agents have been associated with thyroid dysfunction and cardiovascular adverse effects like subclinical hypothyroidism, bradycardia, and sinus arrest, even at therapeutic doses. Case presentation: Here, we reported a case of a 17-year-old Han Chinese female who developed symptomatic hypothyroidism, sinus bradycardia, and sinus arrest while being treated with lithium and paliperidone for bipolar disorder with psychotic features including auditory hallucinations. Her workup suggested that these adverse effects might be related to the combined lithium and paliperidone treatment, although other causes could not be ruled out. After discontinuing both medications, her thyroid function and heart rhythm normalized over 20 days. Conclusion: To our knowledge, hypothyroidism, sinus bradycardia, and sinus arrest associated with the combined use of lithium and paliperidone had not been reported previously. Further research is warranted to elucidate the potential risks and benefits of this combination therapy for bipolar disorder with psychotic symptoms.

Investigation of bioactive compounds and their correlation with the antioxidant capacity in different functional vinegars.

There are complex and diverse substances in traditional vinegars, some of which have been identified as biologically active factors, but the variety of functional compounds is currently restricted. In this study, it was aimed to determine the bioactive compounds in 10 typical functional vinegars. The findings shown that total flavonoids (0.21-7.19 mg rutin equivalent/mL), total phenolics (0.36-3.20 mg gallic acid equivalent/mL), and antioxidant activities (DPPH: 3.17-47.63 mmol trolox equivalent/L, ABTS: 6.85-178.29 mmol trolox equivalent/L) varied among different functional vinegars. In addition, the concentrations of the polysaccharides (1.17-44.87 mg glucose equivalent/mL) and total saponins (0.67-12.46 mg oleanic acid equivalent/mL) were determined, which might play key role for the function of tested vinegars. A total of 8 organic acids, 7 polyphenol compounds and 124 volatile compounds were measured and tentatively identified. The protocatechuic acid (4.81-485.72 mg/L), chlorogenic acid (2.69-7.52 mg/L), and epicatechin (1.18-97.42 mg/L) were important polyphenol compounds in the functional vinegars. Redundancy analysis indicated that tartaric acid, oxalic acid and chlorogenic acid were significantly positively correlated with antioxidant capacity. Various physiologically active ingredients including cyclo (Pro-Leu), cyclo (Phe-Pro), cyclo (Phe-Val), cyclo (Pro-Val), 1-monopalmitin and 1-eicosanol were firstly detected in functional vinegars. Principle component analysis revealed that volatiles profile of bergamot Monascus aromatic vinegar and Hengshun honey vinegar exhibited distinctive differences from other eight vinegar samples. Moreover, the partial least squares regression analysis demonstrated that 11 volatile compounds were positively correlated with the antioxidant activity of vinegars, which suggested these compounds might be important functional substances in tested vinegars. This study explored several new functionally active compounds in different functional vinegars, which could widen the knowledge of bioactive factor in vinegars and provide new ideas for further development of functional vinegar beverages.

Bisulfite-free and quantitative detection of 5-formylcytosine in DNA through qPCR.

An easily operated bisulfite-free method was presented to detect and quantify 5fC through quantitative real-time PCR. Malononitrile can selectively label 5fC under mild reaction conditions causing a C-to-T conversion that affects the nick ligation of the complementary pairing oligos, and then the ligation product is amplified and visualized by qPCR.

Base-Resolution Analysis of Deoxyuridine at the Genome Scale Based on the Artificial Incorporation Modified Nucleobase.

Deamination of cytosine and dUMP misincorporation have been found to be capable of producing uracil in the genome. This study presents the AI-seq (artificial incorporation modified nucleobase for sequencing), a "base substitution", which not only is capable of profiling uracil at single-nucleotide resolution and showing its centromeric enrichment but could also reveal that the identified uracil sites are derived from cytosine deamination. All the results indicate the potential biological significance of uracil as the epigenetic modification.

Prevalence and risk factors of anxiety symptoms in first-episode and drug-naïve major depressive disorder patients with metabolic syndrome

Background and objectives Patients with major depressive disorder (MDD) have high comorbidity with metabolic syndrome (MetS), although anxiety is prevalent comorbidity in MDD patients. However, there is no study on anxiety symptoms (AS) in MDD patients with MetS. Therefore, we aimed to identify the prevalence and risk factors of AS in patients with MetS who experienced a first-episode and drug naïve (FEDN) of MDD. Methods In this cross-sectional study, 1718 FEDN of MDD outpatients with MetS were included. Sociodemographic data, clinical characteristics, suicidal attempts, and physical and biochemical parameters were collected. Hamilton Anxiety Rating Scale (HAMA), Hamilton Depression Rating Scale (HAMD), and Positive and Negative Syndrome Scale (PANSS) positive subscale were performed to detect the AS. Multiple linear regression analysis was used to analyze the correlation. Results The prevalence of AS in MDD patients with MetS was 85.96%, which was 1.79 times greater than that in patients with MDD alone (P<0.05). MDD patients with MetS had a greater rate of attempted suicide, a higher HAMD total score, and a higher diastolic blood pressure than MDD patients without AS (P<0.05). Their combination could distinguish AS in MDD patients. Moreover, HAMD score, thyroid-stimulating hormone (TSH) levels, PANSS positive score, and suicide attempts were related to HAMA scores in MDD patients with comorbid MetS (P<0.05). Conclusion There is a significant frequency of AS in MDD patients with MetS. Multiple clinical indicators and metabolic markers are associated with AS in patients with MDD and MetS. (AU)