In order to investigate the influence of aflatoxin B1 (AFB1) on intestinal bacterial flora, 24 Kunming mice (KM mice) were randomly placed into four groups, which were labeled as control, low-dose, medium-dose, and high-dose groups. They were fed intragastrically with 0.4 mL of 0 mg/L, 2.5 mg/L, 4 mg/L, or 10 mg/L of AFB1 solutions, twice a day for 2 months. The hypervariable region V3 + V4 on 16S rDNA of intestinal bacterial flora was sequenced by the use of a high-flux sequencing system on a Miseq Illumina platform; then, the obtained sequences were analyzed. The results showed that, when compared with the control group, both genera and phyla of intestinal bacteria in the three treatment groups decreased. About one third of the total genera and one half of the total phyla remained in the high-dose group. The dominant flora were Lactobacillus and Bacteroides in all groups. There were significant differences in the relative abundance of intestinal bacterial flora among groups. Most bacteria decreased as a whole from the control to the high-dose groups, but several beneficial and pathogenic bacterial species increased significantly with increasing dose of AFB1. Thus, the conclusion was that intragastric feeding with 2.5~10 mg/mL AFB1 for 2 months could decrease the majority of intestinal bacterial flora and induce the proliferation of some intestinal bacteria flora.

The northern root-knot nematode, Meloidogyne hapla, is a biotrophic parasite that infects many crops and causes severe economic losses worldwide. Rapid and accurate detection of M. hapla is crucial for disease forecasting and control. We developed a recombinase polymerase amplification combined with a lateral flow dipstick (RPA-LFD) assay for rapid detection of M. hapla. The primers and probe were designed based on the effector gene 16D10 sequence and were highly specific to M. hapla. The RPA reaction was performed at a wide range of temperatures from 25 to 45°C within 5 to 25 min, and the amplicon was visualized directly on the LFD within 5 min. The detection limits of the RPA-LFD assay were 10⁻³ females and 10⁻² second-stage juveniles/0.5 g of soil, which was 10 times more sensitive than the conventional PCR assay. In addition, the RPA-LFD assay can detect M. hapla from infested plant roots and soil samples, and the entire detection process can be completed within 1.5 h. These results indicate that the RPA-LFD assay is a simple, rapid, specific, sensitive, and visual method that can be used for rapid detection of M. hapla in the field and in resource-limited conditions.

In light of the increasingly adverse environmental conditions and the concomitant challenges to the survival of important crops, there is a pressing need to enhance the resilience of pepper seedlings to extreme weather. Carotenoid plays an important role in plants’ resistance to abiotic stress. Nevertheless, the relationship between carotenoid biosynthesis and sweet pepper seedlings’ resistance to different abiotic stresses remains uncertain. In this study, the carotenoid content in abiotic-stressed sweet pepper seedling roots was determined, revealing that carotenoid content was extremely significantly elevated by more than 16-fold under salt stress, followed by drought stress (8-fold), and slightly elevated by only about 1-fold under waterlogging stress. After that, serine/threonine-protein phosphatase 2A (PP2A) was found to be the suitable reference gene (RG) in sweet pepper seedling roots under different abiotic stresses by using RT-qPCR and RefFinder analysis. Subsequently, using PP2A as the RG, RT-qPCR analysis showed that the expression level of most genes associated with carotenoid biosynthesis was extremely significantly up-regulated in sweet pepper seedlings under salt and drought stress. Specifically, violoxanthin deepoxidase (VDE) was significantly up-regulated by more than 481- and 36-fold under salt and drought stress, respectively; lycopene epsilon cyclase (LCYE) was significantly up-regulated by more than 840- and 23-fold under salt and drought stress, respectively. This study contributes to a more comprehensive understanding of the carotenoid biosynthesis pathway serving as a major source of retrograde signals in pepper subjected to different abiotic stresses.

Bast fibrous plants are recognized as potential sources of pectin, yet the structural characteristics and functional properties of pectic polysaccharides derived from these plants remain insufficiently investigated. In this study, three pectic polysaccharides (HP, KP, and RP) were isolated from the bast fibers of Cannabis sativa L. (hemp), Hibiscus cannabinus L. (kenaf), and Boehmeria nivea L. (ramie) using an ammonium oxalate solution. Their chemical composition, monosaccharide profile, molecular weight, microstructure, and functional groups were analyzed by spectroscopic and chromatographic techniques. These polysaccharides exhibited remarkable uronic acid content (50.49–61.14%), a relatively low degree of esterification (19.51–34.26%), and high molecular weights ranging from 147.10 to 242.16 kDa. The predominant neutral sugars identified were rhamnose, arabinose, and galactose. Furthermore, HP, KP, and RP demonstrated superior thermal stability, emulsifying properties, water/oil holding capacity, and cholesterol binding ability compared with commercial citrus pectin (CP). They also exhibited stronger radical scavenging activity, with KP showing particularly notable antioxidant performance (IC₅₀ = 1856 and 1485 μg/mL for the DPPH and ABTS assays, respectively). Overall, these findings indicate that bast fibrous plants are promising alternative sources of pectic polysaccharides with favorable antioxidant properties, supporting their potential application as food additives or functional ingredients.

Cyperus difformis is a problematic annual weed in rice fields and is widely distributed throughout tropical to warm temperate regions of the world. In June 2019, many galls were observed on the roo...