Vitamin B12 Enriched in Spinach and its Effects on Gut Microbiota.

Meat and fermented foods are the main source of vitamin B12 (cobalamin) for human beings. Therefore, daily cobalamin intake is a big problem for vegans. In this study, cyanocobalamin (CNCBL) was added to the culture broth for cobalamin enrichment in spinach. After 36 h of cultivation, the accumulated CNCBL in the spinach leaves (wet weight) was as high as 0.48% (concentration), and the leaves still contained 0.94 ± 0.11 µg/g CNCBL after boiling, which could provide consumer daily requirement of CNCBL. Because CNCBL supplementation had adverse effects on gut microbiota, this study focused on the effect of the combination of spinach and CNCBL on gut microbiota as well. After the boiled leaves were passed through an in vitro gastrointestinal tract simulation system, it was found that the spinach protected CNCBL against the low-pH gastric acid. Moreover, compared with the CNCBL supplement group, the relative abundances of Bacteroides and Firmicutes increased, and the relative abundance of Proteobacteria, especially Escherichia spp., reduced. Analysis of short-chain fatty acids (SCFAs) showed that cobalamin-rich spinach was positively correlated with Bacteroides, propionate, and butyrate. The results showed that the method of enriching spinach with CNCBL was effective and had beneficial effects on gut microbiota and SCFAs.

Gut microbiota affect the formation of calcium oxalate renal calculi caused by high daily tea consumption.

Kidney stones are a common and frequently occurring disease worldwide. Stones can cause urinary tract obstruction, pain, haematuria, and other symptoms. In this study, the relationship between calcium oxalate renal calculi and gut microbiota was considered. The dietary habits of 30 patients with calcium oxalate kidney stones and 30 healthy people were investigated. The 16S rDNA sequences and short-chain fatty acids (SCFAs) in their stool samples were analysed. We identified 5 genera of the gut microbiota as biomarkers for calcium oxalate renal calculi, namely, Bacteroides, Phascolarctobacterium, Faecalibacterium, Akkermansia, and Lactobacillus, with a receiver operating characteristic (ROC) curve value of 0.871 (95% confidence interval (CI) 0.785-0.957). Phascolarctobacterium and Faecalibacterium showed a positive relationship with SCFA synthesis to reduce the risk of kidney stones. Meanwhile, according to the analysis, Lactobacillus spp. made the largest contribution (79%) to prevent kidney stones caused by tea consumption, since tea offers the great parts of oxalate in kidney stone formation. Three strains of Lactobacillus spp. were isolated from stools of a healthy person with a high level of tea consumption who did not suffer from kidney stones. All these strains survived in the colon with supplementation of high concentrations of tea and efficiently degraded oxalic acid (Ca. 50%) in an in vitro colonic simulation. Therefore, a suitable adjustment of the gut microbiota or SCFA concentration enhanced the degradation of oxalate from food, which can be applied to prevent the formation of calcium oxalate renal calculi caused by tea. KEY POINTS: • Five genera, including Lactobacillus, were identified as biomarkers for calcium oxalate renal calculi. • Lactobacillus is a potential gut bacterium associated with preventing kidney stone formation. • Isolated Lactobacillus strains have the ability to degrade oxalic acid in vitro.

Fluorescent carbon dots derived from urine and their application for bio-imaging.

This study aims to obtain water-soluble fluorescent carbon dots (C-dots) from low-value metabolites through a simple, economical, one-step synthetic route. The urine C-dots (UCDs) and hydrothermally treated urine C-dots (HUCDs) were obtained, respectively, using straightforward Sephadex filtration method from human adults and hydrothermal reaction method. The UCDs and HUCDs emit fluorescence upon being excited with ultraviolet light with a quantum yield of 4.8% and 17.8%, respectively. TEM analysis revealed that UCDs and HUCDs had an average size of 2.5 nm and 5.5 nm, respectively. X-ray photoelectron spectroscopy (XPS) analysis showed the UCDs and HUCDs were mainly composed of carbon, oxygen and nitrogen. Fourier-transform infrared (FTIR) spectroscopy demonstrated the presence of functional groups, such as amino, hydroxyl, carboxylate and carbonyl groups onto the C-dots. The UCDs and HUCDs can be directly used for in vivo and in vitro imaging in Hela cells, Caenorhabditis elegans, onion epidermal cells and bean sprouts. The cytotoxicity study revealed that the UCDs and HUCDs were not toxic to normal rat kidney (NKR) cells with good biocompatibility. The results revealed that the C-dots derived from urine have good biocompatibility, strong fluorescence and may have potential to be a safe fluorescent probe for bio-imaging.

Neonatal hearing screening: a combined click evoked and tone burst otoacoustic emission approach.

OBJECTIVE: This study evaluated an alternative transient evoked otoacoustic emissions method for screening hearing in newborn babies that may reduce the referral rate of initial screening. METHODS: A total of 1,033 neonates (2,066 ears) from two hospitals were recruited. Subjects had their hearing screened in both ears using a combined approach-both click evoked OAEs (CEOAEs) and 1kHz tone burst evoked OAEs (TBOAEs). RESULTS: 1kHz TBOAEs were more robust than CEOAEs in terms of emission response level and signal-to-noise ratio (SNR) at both 1 and 1.5kHz frequency bands. The prevalence rate for CEOAE and TBOAE responses in these two frequency bands was significantly different. The combined protocol significantly reduced the referral rate-by almost 2 percentage points for first time screening. CONCLUSIONS: The implementation of a combined 1kHz TBOAE/CEOAE screening protocol is a feasible and effective way to reduce referral rates, and hence false positive rates, in neonatal hearing screening programs.