Enrofloxacin Rapid Detection in Aquatic Foods: Based on DNA Aptamer Sensor.

Enrofloxacin (ENR) is widely used as a synthetic fluoroquinolone antibiotic for disease control in aquatic animals. ENR aptamers were screened in this study using the magnetic bead-SELEX method, and a graphene oxide fluorescent sensor was developed to detect the ENR residues in aquatic products. Firstly, ENR was conjugated to amino magnetic beads by amidation reaction, and then the aptamer sequences showing high affinity to ENR were screened step by step by using the SELEX screening method. Finally, after 10 rounds of SELEX screening, six candidate aptamers with high affinity were obtained. Among these, ENR-Apt 6 was selected based on its secondary structure features, high affinity (Kd = 35.08 nM), and high specificity to ENR. Furthermore, a fluorescent sensor was prepared using graphene oxide and ENR-Apt 6. The results showed that the linear range of the sensor could reach 600 nM (R2 = 0.986), while its optimal linear range was 1-400 nM (R2 = 0.991), with the lowest detection limit of 14.72 nM. The prepared sensor was successfully used for the detection of ENR in real samples, with a recovery range of 83.676-114.992% and a relative standard deviation < 10% for most of the samples.

Aptamer-Based Sensor for Rapid and Sensitive Detection of Ofloxacin in Meat Products.

Ofloxacin (OFL) is widely used in animal husbandry and aquaculture due to its low price and broad spectrum of bacterial inhibition, etc. However, it is difficult to degrade and is retained in animal-derived food products, which are hazardous to human health. In this study, a simple and efficient method was developed for the detection of OFL residues in meat products. OFL coupled with amino magnetic beads by an amination reaction was used as a stationary phase. Aptamer AWO-06, which showed high affinity and specificity for OFL, was screened using the exponential enrichment (SELEX) technique. A fluorescent biosensor was developed by using AWO-06 as a probe and graphene oxide (GO) as a quencher. The OFL detection results could be obtained within 6 min. The linear range was observed in the range of 10-300 nM of the OFL concentration, and the limit of the detection of the sensor was 0.61 nM. Furthermore, the biosensor was stored at room temperature for more than 2 months, and its performance did not change. The developed biosensor in this study is easy to operate and rapid in response, and it is suitable for on-site detection. This study provided a novel method for the detection of OFL residues in meat products.

Preparation of Sweet Potato Porous Starch by Marine Dextranase and Its Adsorption Characteristics.

Dextranase (EC 3.2.1.11) is primarily applied in food, sugar, and pharmaceutical industries. This study focuses on using a cold shock Escherichia coli expression system to express marine dextranase SP5-Badex; enzyme activity increased about 2.2-fold compared to previous expression. This enzyme was employed to produce sweet potato porous starch, with special emphasis on the pore size of the starch. The water and oil adsorption rates of the porous starch increased by 1.43 and 1.51 times, respectively. Extensive Fourier transform infrared spectroscopy and X-ray diffraction revealed that the crystal structure of the sweet potato starch was unaltered by enzymatic hydrolysis. The adsorption capacities of the porous starch for curcumin and proanthocyanidins were 9.59 and 12.29 mg/g, respectively. Notably, the stability of proanthocyanidins was significantly enhanced through their encapsulation in porous starch. After 2.5 h of ultraviolet irradiation, the free radical scavenging rate of the encapsulated proanthocyanidins remained at 95.10%. Additionally, after 30 days of sunlight exposure, the free radical scavenging rate of the encapsulated proanthocyanidins (84.42%) was significantly higher than that (24.34%) observed in the control group. These research findings provide substantial experimental evidence for preparing sweet potato porous starch using marine dextranase.

The Screening and Identification of a Dextranase-Secreting Marine Actinmycete Saccharomonospora sp. K1 and Study of Its Enzymatic Characteristics.

In this study, an actinomycete was isolated from sea mud. The strain K1 was identified as Saccharomonospora sp. by 16S rDNA. The optimal enzyme production temperature, initial pH, time, and concentration of the inducer of this actinomycete strain K1 were 37 °C, pH 8.5, 72 h, and 2% dextran T20 of medium, respectively. Dextranase from strain K1 exhibited maximum activity at 8.5 pH and 50 °C. The molecular weight of the enzyme was <10 kDa. The metal ions Sr2+ and K+ enhanced its activity, whereas Fe3+ and Co2+ had an opposite effect. In addition, high-performance liquid chromatography showed that dextran was mainly hydrolyzed to isomaltoheptose and isomaltopentaose. Also, it could effectively remove biofilms of Streptococcus mutans. Furthermore, it could be used to prepare porous sweet potato starch. This is the first time a dextranase-producing actinomycete strain was screened from marine samples.

Morphological Changes and Strong Cytotoxicity in Yarrowia lipolytica by Overexpressing Delta-12-Desaturase.

In this study, delta-12 desaturase was overexpressed in Yarrowia lipolytica using the single-copy integrative vector pINA1312 and multicopy integrative vector pINA1292, resulting in the engineered yeast strains 1312-12 and 1292-12, respectively. The content of intracellular linoleic acid (LA) in the 1292-12 strain was much higher than in the 1312-12 strain and the control group. One interesting finding was that the 1292-12 strain showed obvious changes in surface morphology. The 1292-12 colonies were much smaller and smoother, whereas their single cells became much larger compared to the control strain. In addition, the dry cell weight (DCW) of the 1292-12 strain was obviously increased from 8.5 to 12.7 g/L, but the viable cell number sharply decreased from 107 to 105/mL. These results indicated that increased LA content in Yarrowia lipolytica could induce morphological changes or even oxidative stress-dependent cell death. The reactive oxygen species (ROS) and malondialdehyde (MDA) were accumulated in the 1292-12 strain, while the antioxidant activities of intracellular catalase (CAT) and superoxide dismutase (SOD) were significantly decreased by 27.6 and 32.0%, respectively. Furthermore, it was also revealed that these issues could be ameliorated by the exogenous supplementation of vitamin C, fish and colza oil.

CLDN5: From structure and regulation to roles in tumors and other diseases beyond CNS disorders.

Claudin-5 (CLDN5) is an essential component of tight junctions (TJs) and is critical for the integrity of the blood-brain barrier (BBB), ensuring homeostasis and protection from damage to the central nervous system (CNS). Currently, many researchers have summarized the role and mechanisms of CLDN5 in CNS diseases. However, it is noteworthy that CLDN5 also plays a significant role in tumor growth and metastasis. In addition, abnormal CLDN5 expression is involved in the development of respiratory diseases, intestinal diseases, cardiac diseases, and diabetic ocular complications. This paper aims to review the structure, expression, and regulation of CLDN5, focusing on its role in tumors, including its expression and regulation, effects on malignant phenotypes, and clinical significance. Furthermore, this paper will provide an overview of the role and mechanisms of CLDN5 in respiratory diseases, intestinal diseases, cardiac diseases, and diabetic ocular complications.

In Situ Surface Reconstruction toward Planar Heterojunction for Efficient and Stable FAPbI3 Quantum Dot Solar Cells.

Pure-phase α-FAPbI3 quantum dots (QDs) are the focus of an increasing interest in photovoltaics due to their superior ambient stability, large absorption coefficient, and long charge-carrier lifetime. However, the trap states induced by the ligand-exchange process limit the photovoltaic performances. Here, a simple post treatment using methylamine thiocyanate is developed to reconstruct the FAPbI3 -QD film surface, in which a MAPbI3 capping layer with a thickness of 6.2 nm is formed on the film top. This planar perovskite heterojunction leads to a reduced density of trap-states, a decreased band gap, and a facilitated charge carrier transport. As a result, a record high power conversion efficiency (PCE) of 16.23% with negligible hysteresis is achieved for the FAPbI3 QD solar cell, and it retains over 90% of the initial PCE after being stored in ambient environment for 1000 h.

Stable Electron-Transport-Layer-Free Perovskite Solar Cells with over 22% Power Conversion Efficiency.

Due to their low cost and simplified production process, electron-transport-layer-free (ETL-free) perovskite solar cells (PSCs) have attracted great attention recently. However, the performance of ETL-free PSCs is still at a disadvantage compared to cells with a conventional n-i-p structure due to the severe recombination of charge carriers at the perovskite/anode interface. Here, we report a strategy to fabricate stable ETL-free FAPbI3 PSCs by in situ formation of a low dimensional perovskite layer between the FTO and the perovskite. This interlayer gives rise to the energy band bending and reduced defect density in the perovskite film and indirect contact and improved energy level alignment between the anode and perovskite, which facilitates charge carrier transport and collection and suppresses charge carrier recombination. As a result, ETL-free PSCs with a power conversion efficiency (PCE) exceeding 22% are achieved under ambient conditions.

Overexpression of Shinorhizobium meliloti flavohemoglobin improves cell growth and fatty acid biosynthesis in oleaginous fungus Mucor circinelloides.

Oxygen availability is a limiting factor for lipid biosynthesis in eukaryotic microorganisms. Two bacterial hemoglobins from Vitreoscilla sp. (VHb) and Shinorhizobium meliloti (SHb), which deliver oxygen to the respiratory chain to produce more ATP, were introduced into Mucor circinelloides to alleviate oxygen limitation, thereby improving cell growth and fatty acid production. The VHb and SHb genes were integrated into the M. circinelloides MU402 genome by homologous recombination. VHb and SHb protein expression was verified by carbon monoxide difference spectrum analysis. The biomass was increased by ~ 50% in the strain expressing SHb compared with VHb. The total fatty acid (TFA) content of the strain expressing SHb reached 15.7% of the dry cell weight (~ 40% higher than that of the control strain) during flask cultivation. The biomass and TFA content were markedly increased (12.1 g/L and 21.1% dry cell weight, respectively) in strains expressing SHb than strains expressing VHb during fermenter cultivation. VHb and SHb expression also increased the proportion of polyunsaturated fatty acids. Overexpressed bacterial hemoglobins, especially SHb, increased cell growth and TFA content in M. circinelloides at low and high aeration, suggesting that SHb improves fatty acid production more effectively than VHb in oleaginous microorganisms.

Liamocins biosynthesis, its regulation in Aureobasidium spp., and their bioactivities.

Liamocins synthesized by Aureobasidium spp. are glycolipids composed of a single mannitol or arabitol headgroup linked to either three, four or even six 3,5-dihydroxydecanoic ester tail-groups. The highest titer of liamocin achieved was over 40.0 g/L. The substrates for liamocins synthesis include glucose, sucrose, xylose, mannitol, and others. The Pks1 is responsible for the biosynthesis of the tail-group 3,5-dihydroxydecanoic acid, both mannitol dehydrogenase (MDH) and mannitol 1-phosphate 5-dehydrogenase (MPDH) catalyze the mannitol biosynthesis and the arabitol biosynthesis is controlled by arabitol dehydrogenase (ArDH). The ester bond formation between 3,5-dihydroxydecanoic acid and mannitol or arabitol is catalyzed by the esterase (Est1). Liamocin biosynthesis is regulated by the specific transcriptional activator (Gal1), global transcriptional activator (Msn2), various signaling pathways, acetyl-CoA flux while Pks1 activity is controlled by PPTase activity. The synthesized liamocins have high bioactivity against the pathogenic bacteria Streptococcus spp. and some kinds of cancer cells while Massoia lactone released liamocins which exhibited obvious antifungal and anticancer activities. Therefore, liamocins and Massoia lactone have many applications in various sectors of biotechnology.

The GATA type transcriptional factors regulate pullulan biosynthesis in Aureobasidium melanogenum P16.

Aureobasidium melanogenum P16, the high pullulan producer, had only one GATA type transcriptional activator AreA and one GATA type transcriptional repressor AreB. It was found that 2.4 g/L of (NH4)2SO4 had obvious nitrogen repression on pullulan biosynthesis by A. melanogenum P16. Removal of the AreB gene could make the disruptant DA6 produce 34.8 g/L pullulan while the P16 strain only produced 28.8 g/L pullulan at the efficient nitrogen condition. Further both removal of the native AreA gene and overexpression of the mutated AreAS628-S678 gene with non-phosphorylatable residues could render the transformant DEA12 to produce 39.8 g/L pullulan. The transcriptional levels of most of the genes related to pullulan biosynthesis in the transformant DEA12 were greatly enhanced. The mutated AreAS628-S678 was localized in the nuclei of the transformant DEA12 while the native AreA was distributed in the cytoplasm in A. melanogenum P16. This meant that nitrogen repression on pullulan biosynthesis in the transformant DEA12 was indeed significantly relieved. This was the first time to report that the GATA type transcriptional factors of nitrogen catabolite repression system could regulate pullulan biosynthesis in Aureobasidium spp.

[The application of neonatal intensive care unit main caregiver ability evaluation index system in premature infants with hypoxic ischemic encephalopathy].

OBJECTIVE: To explore the effect of main caregiver ability evaluation index system (MCAEIS) in neonatal intensive care unit (NICU) in the treatment of hypoxic-ischemic encephalopathy (HIE). METHODS: One hundred and eight cases of HIE preterm infants treated in NICU of the First Hospital of Hebei Medical University from August 2018 to August 2019 were retrospectively analyzed. The infants were divided into routine nursing control group and MCAEIS group, 54 cases each. The control group recieved NICU routine care, and the MCAEIS group was given care by NICU MCAEIS. The nursing ability of the main caregivers in the two groups was evaluated by self-made caregiver ability self-assessment questionnaire; the neurological function was assessed by neonatal behavioral neurological score (NBNA) at discharge and one month after discharge; the incidence of neurological sequelae mental retardation [development quotient (DQ) < 75], epilepsy, cerebral palsy and so on were observed. RESULTS: There were no significant differences in the scores of nursing knowledge, nursing technology or nursing ability between the two groups at admission, but the above scores were significantly improved in the two groups at discharge, and the scores of nursing knowledge, nursing technology and nursing ability of main caregivers in the MCAEIS group were significantly higher than those in the routine nursing control group (nursing knowledge score: 29.84±3.47 vs. 20.83±3.94,nursing technology: 31.47±4.56 vs. 25.12±4.18,nursing ability: 17.28±2.39 vs.12.83±4.78), with significant differences (all P < 0.05). One month after discharge, the neurological function score in MCAEIS group was significantly higher than that of routine nursing control group (39.67±3.76 vs. 35.87±5.71, P < 0.001). The incidence of neurological sequelae in MCAEIS group was significantly lower than that in the routine nursing control group [1.85% (1/54) vs. 12.96% (7/54), P = 0.031]. CONCLUSIONS: NICU MCAEIS could scientifically and systematically evaluate the nursing ability of the main caregivers, improve the nursing ability of children, and provide a reference for clinical nursing, which is worthy of widely application.

Embolization of hepatic arterioportal shunt with ethanol-soaked gelatin sponge.

OBJECTIVE: The objective of this study is to investigate the effect of ethanol-soaked gelatin sponge (ESG) in the treatment of hepatic arterioportal shunt (APS). METHODS: Hepatocellular carcinoma (HCC) patients with APS were divided into experimental group (Group E) and control group (Group C). Patients in Group E were treated with ESG for APS embolization, whereas patients in Group C were treated with polyvinyl alcohol particles for APS embolization, with other treatment unchanged. APS and the Eastern Cooperative Oncology Group (ECOG) physical status scores of patients before and after the first treatment and further consultation in the 6th week and the survival rate in follow-up visit were recorded. The changes of liver function during treatment were monitored. RESULTS: Before the first treatment, there was no statistical significant difference in APS between two groups. After that, APS in Groups E (P = 2.49 × 10-7) and C (P = 2.10 × 10-4) was improved. In further consultation, APS in Groups E (P = 2.73 × 10-13) and C (P = 2.90 × 10-8) was further improved after examinations and corresponding treatment. After the first treatment and further consultation, APS score was lower in Group E than in Group C, and there were still five patients whose APS score was 2 in Group C. Quality of life in two groups was effectively controlled without getting worse and the ECOG score reduced. Liver function in the two groups did not worsen with the use of liver protective drugs. No deaths occurred in Group E, whereas two patients died in Group C during treatment and follow-up visit. CONCLUSION: The results show that ESG can effectively reduce APS score and improve the survival rate of HCC patients.