Exploration of pathogenic microorganism within the small intestine of necrotizing enterocolitis.

BACKGROUND: Necrotizing enterocolitis (NEC) is the most common severe gastrointestinal emergency in neonates. We designed this study to identify the pathogenic microorganisms of NEC in the microbiota of the small intestine of neonates. METHODS: Using the 16S ribosomal DNA (rDNA) sequencing method, we compared and analyzed the structure and diversity of microbiotas in the intestinal feces of different groups of neonates: patients undergoing jejunostomy to treat NEC (NP group), neonates undergoing jejunostomy to treat other conditions (NN group), and neonates with NEC undergoing conservative treatment (NC group). We took intestinal feces and saliva samples from patients at different time points. RESULTS: The beta diversities of the NP, NN, and NC groups were all similar. When comparing the beta diversities between different time points in the NP group, we found similar beta diversities at time points E1 to E3 but significant differences between the E2-E3 and E4 time points: the abundances of Klebsiella and Enterococcus (Proteobacteria) were higher at the E1-E3 time points; the abundance of Escherichia-Shigella (Proteobacteria) increased at the E2 time point, and the abundance of Klebsiella decreased significantly, whereas that of Streptococcus increased significantly at the E4 time point. CONCLUSIONS: Our results suggest that the pathological changes of intestinal necrosis in the small intestine of infants with NEC are not directly caused by excessive proliferation of pathogenic bacteria in the small intestine. The sources of microbiota in the small intestine of neonates, especially in premature infants, may be affected by multiple factors.

Quantitative analyses of the bitterness and astringency of catechins from green tea.

Bitterness and astringency are two important quality attributes of green tea infusion, and catechins are the main contributor to the bitterness and astringency. The aim of this work was to quantitatively analyse the bitterness and astringency of green tea infusion according to the concentrations of catechins. The concentration-taste curves of catechins showed a pattern that fit the cubic functions, and their R2 values were higher than 0.956. The bitterness of green tea was highly correlated with the concentrations of (-)-epigallocatechin gallate and (-)-epicatechin gallate (ECG) (R2 = 0.7769, p < 0.01), and the astringency (R2 = 0.7878, p < 0.01) was highly correlated with the concentrations of ECG and flavonol glycosides (myricetin 3-O-galactoside and quercetin-3-O-rutinoside). Taste interactions between different catechins and between catechins and other substances were determined. These results may enhance the understanding of tea chemistry for improving the taste of products from green tea.

Estimating the age of Lucilia illustris during the intrapuparial period using two approaches: Morphological changes and differential gene expression.

Lucilia illustris (Meigen, 1826) (Diptera: Calliphoridae) is a cosmopolitan species of fly that has forensic and medical significance. However, there is no relevant study regarding the determination of the age of this species during the intrapuparial period. In this study, we investigated the changes in both morphology and differential gene expression during intrapuparial development, with an aim to estimate the age of L. illustris during the intrapuparial stage. The overall intrapuparial morphological changes of L. illustris were divided into 12 substages. Structures such as the compound eyes, mouthparts, antennae, thorax, legs, wings, and abdomen, each capable of indicating age during the intrapuparial stage, were observed in detail, and the developmental progression of each of these structures was divided into six to eight stages. We recorded the time range over which each substage or structure appeared. The differential expression of the three genes 15_2, actin, and tbp previously identified for predicting the timing of intrapuparial development was measured during L. illustris metamorphosis. The expression of these genes was quantified by real-time PCR, and the results revealed that these genes can be used to estimate the age of L. illustris during the intrapuparial period, as they exhibit regular changes and temperature dependence. This study provides an important basis for estimating the minimum postmortem interval (PMImin) in forensic entomology according to changes in intrapuparial development and differential gene expression. Furthermore, combination of the two approaches can generate a more precise PMImin than either approach alone.

Development of the green bottle fly Lucilia illustris at constant temperatures.

Lucilia illustris (Meigen 1826) (Diptera: Calliphoridae) is a cosmopolitan species that commonly colonizes carcasses and occasionally acts as parasites of humans or livestock, making it an insect of significant importance in forensic, medical, and veterinary entomology. However, only a few studies have documented the development of L. illustris. Here, we studied the developmental duration and larval body length changes of L. illustris under nine constant temperatures ranging from 15.0 to 35.0°C. Using these results, we generated an isomorphen diagram, thermal summation model, and isomegalen diagram for L. illustris. Simulation equations of the variation in the larval body length with time after hatching and variation in time after hatching with the body length were also obtained. L. illustris could complete its life cycle in 15.0-32.5°C, while its development was incomplete at 35.0°C, where the pupae failed to transform into adults. The development duration was 955.5±16.9, 625.7±16.9, 509.3±18.3, 410.0±17.0, 346.7±12.2, 290.2±6.7, 257.1±8.9, and 234.8±3.2h at 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, and 32.5°C, respectively. The developmental threshold temperature and thermal constant were 9.30±0.19°C and 5367.2±98.3°Ch, respectively. These results provide an important basis for the use of L. illustris development-based estimation of the minimum postmortem interval (PMImin) in forensic entomology.

Improving the sweet aftertaste of green tea infusion with tannase.

The present study aims to improve the sweet aftertaste and overall acceptability of green tea infusion by hydrolyzing (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) with tannase. The results showed that the intensity of the sweet aftertaste and the score of overall acceptability of the green tea infusion significantly increased with the extension of the hydrolyzing treatment. (-)-Epigallocatechin (EGC) and (-)-epicatechin (EC) were found to be the main contributors for the sweet aftertaste, based on a trial compatibility with EGCG, ECG, EGC, and EC monomers, and a synergistic action between EGC and EC to sweet aftertaste was observed. A 2.5:1 (EGC/EC) ratio with a total concentration of 3.5 mmol/L gave the most satisfying sweet aftertaste, and the astringency significantly inhibited the development of the sweet aftertaste. These results can help us to produce a tea beverage with excellent sweet aftertaste by hydrolyzing the green tea infusion with tannase.