Lactose Intolerance

Characterization and Application of a New β-Galactosidase Gal42 From Marine Bacterium Bacillus sp. BY02

β-Galactosidase plays an important role in medicine and dairy industry. In this study, a new glycoside hydrolase family 42 (GH42) β-galactosidase-encoding gene, gal42, was cloned from a newly isolated marine bacterium Bacillus sp. BY02 and expressed in Escherichia coli. Structural characterization indicated that the encoding β-galactosidase, Gal42, is a homotrimer in solution, and homology modeling indicated that it retains the zinc binding sites of the Cys cluster. The reaction activity of Gal42 was significantly increased by Zn²⁺ (229.6%) and other divalent metal ions (Mn²⁺, Mg²⁺, and Co²⁺), while its activity was inhibited by EDTA (53.9%). Meanwhile, the thermo-stability of the Gal42 was also significantly enhanced by 5 and 10 mM of zinc ion supplement, which suggested that the “Cys-Zn” motif played important roles in both structural stability and catalytic function. Furthermore, Gal42 showed effective lactose hydrolysis activity, which makes the enzyme hydrolyze the lactose in milk effectively. These properties make Gal42 a potential candidate in food technology.

[Efficacy and safety of lactase additive in preterm infants with lactose intolerance: a prospective randomized controlled trial]

OBJECTIVE

To study the efficacy and safety of lactase additive in improving lactose intolerance in preterm infants.

METHODS

A total of 60 preterm infants with lactose intolerance who were admitted to the Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from January 2018 to December 2019 were randomly divided into a lactase treatment group and a control group, with 30 infants in each group. The infants in the lactase treatment group were given 4 drops of lactase additive (180 mg) added into preterm formula or breast milk, and those in the control group were given placebo, oral administration of probiotics (live combined Bifidobacterium, Lactobacillus and Enterococcus powder) at half an hour after feeding (1 g each time, twice a day), and clockwise abdominal massage around the belly button at 1 hour after feeding for 15 minutes each time, 3 times a day. Fecal pH, fecal reducing sugar, growth indicators, symptoms of lactose intolerance, and laboratory markers were measured at the end of the first and second weeks after intervention.

RESULTS

Finally 29 infants in the lactase treatment group and 26 infants in the control group completed the trial. At the end of the first week after intervention, compared with the control group, the lactase treatment group had significantly lower frequency of daily milk vomiting and gastric retention amount (P < 0.05) and a significantly higher proportion of infants with fecal pH > 5.0 (P < 0.05). At the end of the second week after intervention, compared with the control group, the lactase treatment group had significantly lower frequency of daily milk vomiting and 24-hour abdominal circumference difference (P < 0.05) and a significantly higher proportion of infants with the absence of gastric retention, fecal pH > 5.0, or negative reducing sugar in feces (P < 0.05). No adverse reactions associated with the lactase additive or probiotics were observed during the trial.

CONCLUSIONS

Lactase additive can safely and effectively improve the clinical symptoms caused by lactose intolerance in preterm infants.

Zirconia Hybrid Nanoshells for Nutrient and Toxin Detection

Monitoring milk quality is of fundamental importance in food industry, because of the nutritional value and resulting position of milk in daily diet. The detection of small nutrients and toxins in milk is challenging, considering high sample complexity and low analyte abundance. In addition, the slow analysis and tedious sample preparation hinder the large-scale application of conventional detection techniques. Herein, zirconia hybrid nanoshells are constructed to enhance the performance of laser desorption/ionization mass spectrometry (LDI MS). Zirconia nanoshells with the optimized structures and compositions are used as matrices in LDI MS and achieve direct analysis of small molecules from 5 nL of native milk in ≈1 min, without any purification or separation. Accurate quantitation of small nutrient is achieved by introducing isotope into the zirconia nanoshell-assisted LDI MS as the internal standard, offering good consistency to biochemical analysis (BCA) with R²  = 0.94. Further, trace toxin is enriched and identified with limit-of-detection (LOD) down to 4 pm, outperforming the current analytical methods. This work sheds light on the personalized design of material-based tool for real-case bioanalysis and opens up new opportunities for the simple, fast, and cost-effective detection of various small molecules in a broad field.

MTFR2 Promotes the Proliferation, Migration, and Invasion of Oral Squamous Carcinoma by Switching OXPHOS to Glycolysis

MTFR2 is an oncogene involved in the progression of cancer, its' potential mechanism in oral squamous carcinoma remains unknown. The aim of this study was to uncover the bio-function and the mechanism of MTFR2 in the progression of oral squamous carcinoma. We scanned TCGA database to identify MTFR2 as dysregulated genes. qRT-PCR and Western blotting assays were applied to detect the expression pattern of MTFR2 in oral squamous carcinoma. We next established stable MTFR2-overexpressing and MTFR2 knocking down cell lines. A series of experiments were applied and the results indicated that MTFR2 was upregulated in cancer tissue and negatively correlated with the overall survival (OS) of patients in both the TCGA database and our inhouse database. Following experiments showed that MTFR2 promotes proliferation, migration and invasion in an oral squamous carcinoma cell line by switching OXPHOS to glycolysis.

Effects of Prebiotic and Probiotic Supplementation on Lactase Deficiency and Lactose Intolerance: A Systematic Review of Controlled Trials

Lactose intolerance (LI) is characterized by the presence of primarily gastrointestinal clinical signs resulting from colonic fermentation of lactose, the absorption of which is impaired due to a deficiency in the lactase enzyme. These clinical signs can be modified by several factors, including lactose dose, residual lactase expression, concurrent ingestion of other dietary components, gut-transit time, and enteric microbiome composition. In many of individuals with lactose malabsorption, clinical signs may be absent after consumption of normal amounts of milk or, in particular, dairy products (yogurt and cheese), which contain lactose partially digested by live bacteria. The intestinal microbiota can be modulated by biotic supplementation, which may alleviate the signs and symptoms of LI. This systematic review summarizes the available evidence on the influence of prebiotics and probiotics on lactase deficiency and LI. The literature search was conducted using the MEDLINE (via PUBMED) and SCOPUS databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and included randomized controlled trials. For each study selected, the risk of bias was assessed following the Cochrane Collaboration methodology. Our findings showed varying degrees of efficacy but an overall positive relationship between probiotics and LI in relation to specific strains and concentrations. Limitations regarding the wide heterogeneity between the studies included in this review should be taken into account. Only one study examined the benefits of prebiotic supplementation and LI. So further clinical trials are needed in order to gather more evidence.