Long-term effect of plastic feeding on growth and transcriptomic response of mealworms (Tenebrio molitor L.).

Plastic waste has been considered a serious global environmental problem for decades. Despite the high recalcitrance of synthetic plastics, the biodegradation of polyethylene (PE), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC) by some insect larvae has been reported; however, the mechanism of degradation remains largely unknown. We investigated the effects of plastics on the growth of mealworms (larvae of Tenebrio molitor) and their role in PS and PE degradation. Mealworms were capable of ingesting high-impact polystyrene (HIPS), expanded polystyrene (EPS) and low-density polyethylene (LDPE) but not linear low-density polyethylene (LLDPE) or polypropylene (PP). Plastic consumption was negatively dependent on plastic crystallinity. Transcriptome analysis and KEGG mapping revealed that mealworms act as downstream decomposers in plastic depolymerization and that fatty acid degradation pathways may play important roles in the digestion of plastic degradation intermediates produced by gut bacteria. In addition, PS and PE degradation was achieved via the diffusion of extracellular depolymerases, which probably acted on the distal backbone and produce shorter linear chains that containing ≤16 C atoms instead of branched chains. Additionally, the intermediates of PS degradation are expected to be further decomposed by mealworms as xenobiotics. This study provided a preliminary understanding of plastic degradation mechanism by mealworms.

Chromosomal-level reference genome of the incense tree Aquilaria sinensis.

Trees in the genus Aquilaria (Thymelaeaceae) are known as lign aloes, and are native to the forests of southeast Asia. Lign aloes produce agarwood as an antimicrobial defence. Agarwood has a long history of cultural and medicinal use, and is of considerable commercial value. However, due to habitat destruction and over collection, lign aloes are threatened in the wild. We present a chromosomal-level assembly for Aquilaria sinensis, a lign aloe endemic to China known as the incense tree, based on Illumina short-read, 10X Genomics linked-read, and Hi-C sequencing data. Our 783.8 Mbp A. sinensis genome assembly is of high physical contiguity, with a scaffold N50 of 87.6 Mbp, and high completeness, with a 95.8% BUSCO score for eudicotyledon genes. We include 17 transcriptomes from various plant tissues, providing a total of 35,965 gene models. We reveal the first complete set of genes involved in sesquiterpenoid production, plant defence, and agarwood production for the genus Aquilaria, including genes involved in the biosynthesis of sesquiterpenoids via the mevalonic acid (MVA), 1-deoxy-D-xylulose-5-phosphate (DXP), and methylerythritol phosphate (MEP) pathways. We perform a detailed repeat content analysis, revealing that transposable elements account for ~61% of the genome, with major contributions from gypsy-like and copia-like LTR retroelements. We also provide a comparative analysis of repeat content across sequenced species in the order Malvales. Our study reveals the first chromosomal-level genome assembly for a tree in the genus Aquilaria and provides an unprecedented opportunity to address a variety of applied, genomic and evolutionary questions in the Thymelaeaceae more widely.

Characterization of food waste from different sources in Hong Kong.

Food waste from different sources or at different generation stages may have different compositional characteristics and is therefore suitable for recycling into different products. To have a better understanding of their chemical composition, five food waste types were collected, namely, household kitchen waste (HH), preconsumption and postconsumption food waste from a hotel (Hpr and Hpo), wet market food waste (WM) and kitchen waste from a Chinese restaurant (CR), and their compositions were assessed monthly for 1 year. They served as suitable feedstock for various conversion technologies according to their chemical profiles. HH and CR had higher crude protein content (26%) and considerable amounts of minerals, making them nutritionally suitable for feeding animals. Preconsumption food wastes Hpr and WM had more favorable C:N ratios (16.5-17.4) and crude fat contents (4.6-6.5%) as feedstock for composting. Postconsumption food wastes were potential feedstock for the production of biogas and biodiesel because of the higher dry matter (>26%) and fat content (>13%). The coefficients of variation (CV) in all nutrients analyzed except Ca for postconsumption food wastes ranged from 5% to 37%, which showed lower temporal variability than preconsumption food wastes (CVs 10-131%). This implies that the composition of postconsumption food waste was relatively less fluctuating and can be considered a more reliable feedstock for food waste conversion. Implications: Characterization of food waste composition from different sources and determination of their temporal variation were performed to understand their characteristics and facilitate sound food waste management. Separating food wastes according to their sources and types helps reduce their composition variability, and thus increases the consistence in food-waste-derived products and recycling success. Study on temporal variation indicates that postconsumption food wastes varied less with time and could serve as reliable feedstocks for food waste conversion.

Inhibitory effects of Selaginella tamariscina on immediate allergic reactions.

The anti-allergic effects of a 70% ethanol extract from Selaginella tamariscina herb (EST) were evaluated in this study. EST given at the doses of 500 and 1000 mg/kg can inhibit mouse systemic anaphylactic shock induced by compound 48/80 in a dose-dependent manner. It can also dose-dependently block rat homologous passive cutaneous anaphylaxis and skin reactions caused by exogenous histamine and serotonin with a significant difference observed at the dose of 1000 mg/kg. In addition, EST can reduce histamine release from rat peritoneal mast cells triggered by compound 48/80 and an antigen in vitro. When incubated with rat mast cells, the extract (200 microg/ml) can significantly elevate the intracellular cAMP levels. The finding suggests that EST inhibits mast cell-dependent, immediate allergic reactions. Its effects appear to be mediated by reducing the release of vasoactive amines such as histamine from mast cells via stabilizing the cell membrane and weakening the inflammatory action of these amines. Based on these results, Selaginella tamariscina and one of its active components flavonoids may be useful as potential remedies for allergic rhinitis and other allergy-related diseases.

Antiallergic and anti-inflammatory properties of the ethanolic extract from Gleditsia sinensis.

This study was carried out to determine the effects of the 70% ethanolic extract from the anomalous fruits of Gleditsia sinensis LAM. (AFGS) on experimental allergic reactions and inflammation. AFGS (200, 500, 1000 mg/kg, p.o.) dose-dependently inhibited the systemic anaphylactic shock induced by compound 48/80 in mice and cutaneous reactions induced by histamine or serotonin in rats. At doses of 500 and 1000 mg/kg, AFGS showed a clear inhibition on homologous passive cutaneous anaphylaxis in rats. In vitro, AFGS significantly reduced histamine release from rat peritoneal mast cells triggered by compound 48/80 at concentrations of 20 and 50 micro/ml. Moreover, AFGS (500, 1000 mg/kg, p.o.) showed a significant inhibition on the hind paw edema in rats and ear swelling in mice caused by carrageenin and croton oil, respectively. It also clearly inhibited the vascular permeability induced by acetic acid in mice at a dose of 1000 mg/kg. These findings demonstrate that the ethanolic extract from the anomalous fruits of Gleditsia sinensis possesses antiallergic and anti-inflammatory activities, which may be mediated by reducing the release of mediators such as histamine from mast cells and weakening the inflammatory action of these mediators.