Microplastics in tea from planting to the final tea product: Traceability, characteristics and dietary exposure risk analysis.

Tea, sold as tea bags or loose tea, is a popular drink worldwide. We quantified microplastics in loose tea during various stages of production, from planting to processing and brewing. The quantity of microplastics in tea ranged from (70-3472 pcs/kg), with the highest abundance detected during processing, mainly in the rolling stage (2266 ± 1206 pcs/kg tea). Scanning electron microcopy revealed scratches and pits on the surface of microplastics fibers from tea plantation soil and processed tea, and their degradation was characterized by cracks and fractures. Exposure risks, based on an estimated dietary intake of 0.0538-0.0967 and 0.0101-0.0181 pcs /kg body weight /day for children and adults, respectively, are considered very low. This study not only evaluates the extent of research on microplastics pollution in tea, but also assess the risk of people's exposure to microplastics through drinking tea.

Virus-Induced Gene Silencing in the Tea Plant (Camellia sinensis).

The recent availability of a number of tea plant genomes has sparked substantial interest in using reverse genetics to explore gene function in tea (Camellia sinensis). However, a hurdle to this is the absence of an efficient transformation system, and virus-induced gene silencing (VIGS), a transient transformation system, could be an optimal choice for validating gene function in the tea plant. In this study, phytoene desaturase (PDS), a carotenoid biosynthesis gene, was used as a reporter to evaluate the VIGS system. The injection sites of the leaves (leaf back, petiole, and stem) for infiltration were tested, and the results showed that petiole injection had the most effective injection, without leading to necrotic lesions that cause the leaves to drop. Tea leaves were inoculated with Agrobacterium harboring a tobacco rattle virus plasmid (pTRV2) containing a CsPDS silencing fragment. The tea leaves exhibited chlorosis symptoms 7-14 days after inoculation, depending on the cultivar. In the chlorosis plants, the coat protein (CP) of tobacco rattle virus (TRV) was detected and coincided with the lower transcription of CsPDS and reduced chlorophyll content compared with the empty vector control, with 81.82% and 54.55% silencing efficiency of 'LTDC' and 'YSX', respectively. These results indicate that the VIGS system with petiole injection could quickly and effectively silence a gene in tea plants.

The Role of Catechins in Regulating Diabetes: An Update Review.

Catechins are key functional components in tea and have many health benefits, including relieving diabetes. Glucose is necessary for maintaining life. However, when the glucose in the serum exceeds the threshold, it will lead to hyperglycemia. Hyperglycemia is mainly caused by insufficient insulin secretion or insulin resistance. Persistent hyperglycemia can cause various disorders, including retinopathy, nephropathy, neurodegenerative diseases, cardiovascular disease, and diabetes. In this paper, we summarize the research on the underlying mechanisms of catechins in regulating diabetes and elaborate on the mechanisms of catechins in alleviating hyperglycemia by improving insulin resistance, alleviating oxidative stress, regulating mitochondrial function, alleviating endoplasmic reticulum stress, producing anti-inflammatory effects, reducing blood sugar source, and regulating intestinal function. This review will provide scientific direction for future research on catechin alleviating diabetes.

[Effects of early administration of imipenem on subeshcar and plasma TNF-alpha in rabbits with severe burns].

OBJECTIVE: To study the changes in subeschar fluid and plasma TNF-alpha in rabbits with severe burns in response to early administration of imipenem (IPM). METHODS: Sixteen rabbits with severe burns were randomized into 2 two equal groups to receive treatment with 100 mg (100 ml) of IPM q8 hx3 days and equivalent volume of saline , respectively. The levels of TNF-alpha in the subeschar tissue fluids and plasma were determined by double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) after the first initial dose of 100 mg of imipenem/cilastatin, lasting 3 days. RESULTS: The plasma TNF-alpha levels in rabbits increased after the burn injury, reaching the peak level 16 h postburn and sustained the high levels till 72 h. At the same time point, TNF-alpha levels in the subeschar tissue fluids increased evidently in comparison with the plasma level, but both were lowered with early administration of imipenem (P<0.05). CONCLUSION: Subeschar and plasma levels of TNFalpha can be significantly lowered with early-stage administration of imipenem, suggesting that IPM inhibits the release of TNFalpha and endotoxin to relieve or prevent endotoxemia after sever burn injury in rabbits.