Changes in Homogalacturonan Metabolism in Banana Peel during Fruit Development and Ripening.

Though numerous studies have focused on the cell wall disassembly of bananas during the ripening process, the modification of homogalacturonan (HG) during fruit development remains exclusive. To better understand the role of HGs in controlling banana fruit growth and ripening, RNA-Seq, qPCR, immunofluorescence labeling, and biochemical methods were employed to reveal their dynamic changes in banana peels during these processes. Most HG-modifying genes in banana peels showed a decline in expression during fruit development. Four polygalacturonase and three pectin acetylesterases showing higher expression levels at later developmental stages than earlier ones might be related to fruit expansion. Six out of the 10 top genes in the Core Enrichment Gene Set were HG degradation genes, and all were upregulated after softening, paralleled to the significant increase in HG degradation enzyme activities, decline in peel firmness, and the epitope levels of 2F4, CCRC-M38, JIM7, and LM18 antibodies. Most differentially expressed alpha-1,4-galacturonosyltransferases were upregulated by ethylene treatment, suggesting active HG biosynthesis during the fruit softening process. The epitope level of the CCRC-M38 antibody was positively correlated to the firmness of banana peel during fruit development and ripening. These results have provided new insights into the role of cell wall HGs in fruit development and ripening.

The association between maternal air pollution exposure and the incidence of congenital heart diseases in children: A systematic review and meta-analysis.

Congenital heart diseases (CHDs) are a prevalent form of congenital malformations in newborns. Although previous studies have explored the association between maternal exposure to ambient air pollution and congenital anomalies in offspring, the results still remain ambiguous. To fill the knowledge gap, we performed a systematic review and meta-analysis of existing literature. A comprehensive search of the literature was conducted in PubMed, Embase, and Web of Science until August 12, 2022. We analyzed the relationship between air pollution and multiple CHDs using either a fixed-effect model or a random-effects model. Summary risk estimates of pollution-outcome pairs were calculated based on (i) risk per increment of concentration and (ii) risk at high versus low exposure levels. Additionally, we performed leave-one-out analyses and used funnel plots to assess the potential publication bias. A total of 32 studies were included and four studies utilizing distributed lag nonlinear models (DLNM) models were added to our retrospective review. In the continuous exposure meta-analysis, there were statistically significant negative associations between sulfur dioxide (SO2) and transposition of the great arteries (OR = 0.96; 95 % CI: 0.93-0.99), pulmonary artery and valve defect (OR = 0.90; 95 % CI: 0.83-0.97), and ventricular septal defect (OR = 0.95; 95 % CI: 0.91-0.99). High versus low SO2 exposure was associated with a decreased risk of tetralogy of Fallot [OR = 0.83; 95 % CI: 0.69-0.99]. However, carbon monoxide (CO) increased risk estimates for tetralogy of Fallot in both continuous exposure (OR = 2.25; 95 % CI: 1.42-3.56) and high-low exposure (OR = 1.24; 95 % CI: 1.01-1.54). Particulate matter 10 (PM10) statistically significant increased in the risk of overall CHD with odds ratios of 1.03 (95 % CI: 1.01-1.05) and 1.04 (95 % CI: 1.00-1.09) in continuous and categorical exposure analysis, respectively. These findings provide potential evidence for the association between maternal air pollution exposure and CHDs.

Facile and Scalable Synthesis and Self-Assembly of Chitosan Tartaric Sodium.

Chitosan-based nanostructures have been widely applied in biomineralization and biosensors owing to its polycationic properties. The creation of chitosan nanostructures with controllable morphology is highly desirable, but has met with limited success yet. Here, we report that nanostructured chitosan tartaric sodium (CS-TA-Na) is simply synthesized in large amounts from chitosan tartaric ester (CS-TA) hydrolyzed by NaOH solution, while the CS-TA is obtained by dehydration-caused crystallization. The structures and self-assembly properties of CS-TA-Na are carefully characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H-NMR), X-ray diffraction (XRD), differential scanning calorimeter (DSC), transmission electron microscopy (TEM), a scanning electron microscope (SEM) and a polarizing optical microscope (POM). As a result, the acquired nanostructured CS-TA-Na, which is dispersed in an aqueous solution 20-50 nm in length and 10-15 nm in width, shows both the features of carboxyl and amino functional groups. Moreover, morphology regulation of the CS-TA-Na nanostructures can be easily achieved by adjusting the solvent evaporation temperature. When the evaporation temperature is increased from 4 °C to 60 °C, CS-TA-Na nanorods and nanosheets are obtained on the substrates, respectively. As far as we know, this is the first report on using a simple solvent evaporation method to prepare CS-TA-Na nanocrystals with controllable morphologies.

Ethanol-Precipitation-Assisted Highly Efficient Synthesis of Nitrogen-Doped Carbon Quantum Dots from Chitosan.

Nitrogen-doped carbon quantum dots (NCQDs) were prepared from chitosan through a hydrothermal reaction. When ethanol precipitation was used as the purification method, a high product yield of 85.3% was obtained. A strong blue fluorescence emission with a high quantum yield (QY) of 6.6% was observed from the NCQD aqueous solution. Physical and chemical characteristics of the NCQDs were carefully investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Raman spectra, X-ray photoelectron spectroscopy (XPS), and transient fluorescence spectra. Experimental results showed that diameters of the NCQDs were in the range of 2-10 nm. The carbon quantum dots possess good water dispersibility and precipitation by ethanol. When used for metal ion detection, the detection limit of the NCQDs for Fe3+ was as low as 1.57 µM. This work proposed a facile method to synthesize NCQDs from chitosan with high yield and demonstrated that carbon quantum dots derived from chitosan were promising for ion detection.