The biosorption of Pb(II) from aqueous solutions by lactic acid bacterium, Lactobacillus brevis, was studied. The effects of initial pH, contact time, initial Pb(II) concentration, bacterial concentration, rotate speed and temperature of biosorption of Pb(II) from aqueous solutions were investigated. The optimal condition for Pb²⁺ ions adsorption was observed at pH 6, with the rotate speed of 120 rpm.min⁻¹, bacterial concentration of 3 g.L⁻¹, temperature of 40 °C and contact time of 12 h. The correlation regression coefficients showed that the biosorption process can be well fitted with the Redlich-Peterson, Langmuir, Freundlich and Temkin isotherm models. The equilibrium adsorption capacity reached to 53.632 mg.g⁻¹. Binding energy value was 0.264 kJ/mol, it indicated that the adsorption process seemed to involve chemisorption and physisorption. Kinetics of adsorption was found to fit well with pseudo-second-order and Elovich kinetic equation. Thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of adsorption.

Vibrio parahaemolyticus biofilm poses a serious threat to food safety and human health. However, there is limited knowledge of transcriptional regulatory mechanism during the biofilm formation of this organism. Hence, the RNA sequencing technique was employed to compare the differences in transcriptome profiles between planktonic and biofilm state of V. parahaemolyticus ATCC33847 in this study. Collections of mRNA from planktonic and biofilm cells cultured at 25°C for 36 h were sequenced by studying their biological characteristics. The results showed that there were significant differences in the expression levels of 956 genes in biofilms compared with planktonic cells. These differences suggested that two-component regulatory system (TCS) and quorum sensing (QS) regulated V. parahaemolyticus biofilm formation by affecting important factors such as flagellar motility, Extracellular polymeric substance (EPS) secretion, tripartite ATP-independent (TRAP) transport system and ATP binding cassette (ABC) transport system. The present work in transcriptomics serves as a basis for future studies examining the complex network systems that regulate bacterial biofilm formation.

Aflatoxin B₁ (AFB₁) has mutagenesis, carcinogenesis and teratogenesis effects and mainly found in food crops and their processed foods. AFB₁ exposure can cause acute or chronic liver poisoning, but there were few studies on the persistent effects of acute AFB₁ exposure on the liver. In this study, rat liver injury models were established 2 and 7 days after single exposure to high and low doses of AFB₁. The persistent effects of AFB₁ single acute exposure (ASAE) on rat liver were analyzed from the phenotypic and genetic levels. The results showed that compared with the control group, liver function indexes, MDA content in liver and the number of apoptotic hepatocytes in model groups increased to the highest on the 2nd day after ASAE (p < 0.001). However, the changes of liver coefficient were most significant on the 7th day after ASAE (p < 0.01). The results of liver pathology showed that the liver injury was not alleviated and the activities of antioxidant enzymes GSH-Px and SOD were the lowest on the 7th day (p < 0.001). RNA-Seq results indicated that there were 236, 33, 679, and 78 significantly differentially expressed genes (DEGs) in the model groups (LA-2d, LA-7d, HA-2d, HA-7d) compared with the control group. Among them, the Gtse1 gene related to the proliferation, differentiation and metastasis of liver cancer cells, the Lama5 and Fabp4 gene related to the inflammatory response were significantly DEGs in the four model groups, and the differential expression of the immune system-related Bcl6 gene increased with the prolonged observation time after ASAE. In conclusion, ASAE can cause persistent liver damage in rats. The persistently affected genes Lama5, Gtse1, Fabp4, and Bcl6 possess the potential to be therapeutic targets for liver disease induced by AFB₁.

Aflatoxin B₁ (AFB₁) is extremely hepatotoxic, a causative agent of liver cancer, and can cause symptoms of acute or chronic liver damage. Chito-oligosaccharides (COS), obtained from the degradation of chitosan derived from shrimp and crab shells, is a natural antioxidant substance and its antitumor properties have been widely studied, but less research has been done on the prevention of AFB₁-induced acute liver injury. In this study, rats were acutely exposed to 1 mg/kg BW AFB₁ and simultaneously gavaged with different doses of COS for 8 days. The results showed that COS attenuated the hepatic histopathological changes and reduced serum biochemical indices (ALT, AST, ALP, and TBIL) in rats. It significantly inhibited MDA content and promoted SOD and GSH-Px activity production. Moreover, it also improved hepatocyte apoptosis. Furthermore, AFB₁-vs-HCOS differential genes were enriched with 622 GO entries, and 380 were Biological Processes, 170 were Molecular Functions, 72 were Cellular Components. Differentially expressed genes (DEGs) analyzed by KEGG enrichment were more enriched in pathways, such as metabolism, PPAR signaling pathway, and peroxisome. Q-PCR technique verified that Lama5, Egr1, Cyp2b1, and Gadd45g in DEGs were associated with oxidative stress damage and apoptosis. In conclusion, COS intervention reduces the effect of AFB₁ on hepatic genes and thus reduces the changes in hepatic gene function. Graphical abstract

A method was developed for the quantitative analysis of tetrodotoxin (TTX) in fermentation broth of distiller's yeast by ion chromatography. After extraction with acetonitrile solution (containing 0.1% phosphoric acid) and purification with an ion-exchange column, the tetrodotoxin was separated by ion chromatography and detected by a ultraviolet-visible (UV-VIS) absorbance detector. The experimental results showed that the tetrodotoxin had a good linearity (r2 = 0.997) in the range of 10 - 100 mg/L and the detection limit (3 of signal-to-noise ratio) was 1.0 mg/L. The average recoveries were between 90% - 103% with a relative standard deviation lower than 4.9%. The analysis of real samples verified the reliability of this method and demonstrated that the ion chromatography can be used for the quantification detection of the tetrodotoxin. The degradation experiment results suggested that distiller's yeast had a remarkable effect on the tetrodotoxin degradation.