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In order to investigate the effect of long-term consumption of yak milk on the intestinal flora and metabolism and to explore the correlation between acclimation to monodiet and yak milk intake in high-altitude pastoral areas, this study used metagenomics and metabolomics to evaluate the gut microbial community structure and metabolites of mice fed yak milk or Holstein cow milk. Results showed that compared with the control group (normal saline solution), at the phylum level, ingestion of yak milk improved the relative abundance of Actinobacteria (33.27%), Bacteroidetes (24.31%) and Verrucomicrobia (11.08%), while ingestion of Holstein cow milk increased the relative abundance of Firmicutes (43.74%) and Bacteroidetes (24.75%). At the genus level, yak milk consumption increased the relative abundance of Ackermania (11.80%), Bacteroides (6.09%) and Limosilactobacillus (4.77%), while Holstein cow milk consumption increased the relative abundance of Lactobacillus (28.62%), Duncaniella (6.15%) and Limosilactobacillus (6.49%). Both yak and Holstein cow milk up-regulated carbohydrate and nucleotide metabolism. Furthermore, yak milk significantly up-regulated amino acid metabolism, cofactor and vitamin metabolism, energy metabolism, the biosynthesis of secondary metabolites, and the biosynthesis and metabolism of peptidoglycan. Metabolomics revealed that yak milk increased the contents of metabolites such as VB1, (+/-) 12 (13)-DiHOME, coenzyme Q2 and sulfonymethazine, as well as steroid hormone biosynthesis, cofactor biosynthesis, 2-oxyarboxylate metabolism, VB6 metabolism and phenylalanine metabolism in mice. Investigation of intestinal tissue morphology showed that the intestinal wall became thicker with increasing diversity and richness of the gut microbiota and the intestinal villi became longer and denser without deformity or breakage. In conclusion, yak milk has a positive effect on the intestinal flora and metabolism in mice, and this study provides a scientific basis for further development and utilization of yak milk.

To investigate the inhibitory mechanism of small peptides on carbohydrate digestion, α-amylase and α-glucosidase inhibitory fractions from the water extract and the gastropancreatic digest of dry-cured ham muscle of Wanzhe spotted pigs were separated, purified, identified, and screened for peptide sequences. And the quantum chemical calculation was used to calculate structural and charge parameters including the distribution and energy of the frontier orbitals, electrostatic charge distribution and bond length, in order to speculate the active sites. It was found that the particle size of ham muscle decreased and its hypoglycemic activity increased after proteolysis. Two (S-I and S-II) and three fractions (WY-I, WY-II and WY-III) were obtained from the water extract and the digest after Sephadex column chromatography, respectively. Using mass spectrometry, 104 peptide sequences consisting of 8–24 amino acids were identified from fraction WY-II and five sequences with Peptide Ranker scores greater than 0.7 were selected. The highest occupied orbitals of the five sequences were mainly distributed in the guanidine groups of arginine and the groups close to the amino-terminal end, while the lowest unoccupied orbitals were in the carboxyl terminals and nearby groups. Sequences with lower ΔEL-H values, GPMGPSGPR, LGFGGPSGPNAGR and APAPAPAPAPPK, might be more active. According to Coulomb’s law, the active sites of these three peptides were located at –C106H108 of arginine, –C10H12 of leucine and –C176H177 of lysine, respectively. This study could provide theoretical support for understanding the blood glucose-regulating mechanism of peptides and the nutritional value of local pig breeds.

ObjectiveTo analyze the mental health status and its influencing factors in middle school students under the regular prevention and control of COVID-19， so as to provide references for the intervention and management of their mental health problems.MethodsFrom March 7 to 21， 2021， a stratified random sampling method was used to select 19 352 students from 17 schools in 3 districts and 9 counties of Linyi City， Shandong Province. Basic data were collected through a self-designed questionnaire. All students completed the Symptom Checklist 90 （SCL-90） to assess their mental health status. Then the factors affecting the mental health status of middle school students were screened using independent sample t-test， one-way ANOVA test and multiple stepwise regression analysis.Results① A total of 6 350 （32.81%） middle school students were found to have mental health problems. ② Each SCL-90 factor score and total average score yielded statistical difference among middle school students of different genders， relationships with classmate， closeness to friends， concerns about the epidemic， and pressure exerted by schoolwork （P

This research aimed to study the bacterial community, free amino acid and fatty acid composition in featured dry fermented dairy products from some major pastoral areas of China and to analyze the correlation between bacterial community and free amino acid and fatty acid composition. The V4–V5 region of the bacterial 16S rDNA gene from Suannai Geda from Xinjiang, Qula from Tibet, Naizhazi from Inner Mongolia and milk fan from Yunnan was sequenced by high-throughput sequencing. The contents of fatty acids and free amino acids in these dairy products were determined by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC), respectively. Finally, the correlation of bacterial community with α diversity, fatty acids and free amino acids was evaluated by redundancy analysis (RDA). High-throughput sequencing results showed that a total of 2 421 338 reads were obtained from these dry fermented dairy samples, of which 1 871 524 were clean reads. The bacterial Chao1 and Shannon indexes in milk fan were significantly higher than those in the other three dairy products. The bacterial community compositions in the four dairy products were significantly different, but Firmicutes was dominant in all these products, among which the relative abundance of Firmicutes in Suannai Geda was the highest. The relative abundance of Proteobacteria in Qula was the highest. At the genus level, the bacterial community compositions in the four dairy products were dominated by Lactococcus or Lactobacillus. The contents of 16 fatty acids in milk fan were higher than those in the other three products. A total of 24 free amino acids were detected, among which Suannai Geda contained the largest number (24) of free amino acids, and the contents of most free amino acids in Suannai Geda were higher than those in the other three products. Redundancy analysis showed that alanine was correlated with Acetobacter, Lactobacillus and Streptococcus, and acetic acid and butyric acid were correlated with Acinetobacter. The results of this study may provide a theoretical basis for the industrial production of traditional dry fermented dairy products in different provinces.

Chemotherapy is a commonly utilized treatment strategy for colon cancer, a prevalent malignancy. The study intends to probe the function and mechanism of protocadherin 7 (PCDH7) in colon cancer. Gain or loss of functional assays of PCDH7 was performed. MTT and colony formation assay monitored cell proliferation. Transwell measured migration and invasion. Real-time quantitative polymerase chain reaction and western blot verified the profiles of PCDH7 and the MEKl/2/ERK/c-FOS pathway. Western blot was implemented to confirm the profiles of PP1[alpha], MLC2, and p-MLC2 for evaluating the impact of PCDH7 on homotypic cells in cell (hocic) structures. Further, an in-vivo nude mouse model was engineered to figure out the function and mechanism of PCDH7 in tumor cell growth. As indicated by the data, PCDH7 knockdown boosted the cells' sensitivity to chemotherapy. PCDH7 overexpression facilitated their proliferation and invasion, altered autophagy, induced ferroptosis and hocic, and initiated the profile of the MEKl/2/ERK/c-FOS pathway. MEK1/2/ERK inhibition impaired the inhibitory impact of PCDH7 on colon cancer cells' chemotherapy sensitivity and dampened its pro-cancer function in the cells. In-vivo experiments displayed that PCDH7 overexpression stepped up tumor growth and pulmonary metastasis in colon cancer cells. All in all, the research has discovered that PCDH7 knockdown affects autophagy and induces ferroptosis, hence strengthening colon cancer cells' sensitivity to chemotherapy by repressing the MEKl/2/ERK/c-FOS axis. Key words: PCDH7, MEK, ERK, colon cancer, autophagy, ferroptosis La chimiotherapie est une strategie de traitement couramment utilisee dans le cancer du colon, une tumeur maligne repandue. Cette etude a pour but de sonder la fonction et le mecanisme d'action de la protocadherine 7 (PCDH7) dans le cancer du colon. Des tests de gain ou de perte de fonction de la PCDH7 ont ete realises. Le MTT et le test de formation de colonies ont permis de suivre la progression de la proliferation cellulaire. Le test sur Transwell a mesure la migration et l'invasion. La qRT-PCR et le transfert de western ont permis d'examiner les profils d'expression de la PCDH7 et de la voie MEKl/2/ERK/c-FOS. Le transfert de western a ete utilise pour confirmer les profils d'expression de PP1[alpha], MLC2 et p-MLC2 arm d'evaluer l'impact de PCDH7 sur les structures <> homotypiques (hocic; homotypic cell-in-cell). En outre, un modele de souris nues in vivo a ete concu pour comprendre la fonction et le mecanisme d'action de la PCDH7 dans la croissance des cellules tumorales. Comme l'indiquent les donnees, le knockdown de la PCDH7 accroissait la sensibilite des cellules a la chimiotherapie. La surexpression de la PCDH7 facilitait leur proliferation et leur comportement invasif, affectait l'autophagie, induisait la ferroptose et les structures hocic, et initiait la voie MEKl/2/ERK/c-FOS. L'inhibition de MEK1/2/ERK diminuait l'impact inhibiteur de PCDH7 sur la sensibilite des cellules cancereuses du colon a la chimiotherapie et attenuait sa fonction procancereuse dans les cellules. Des experiences in vivo ont montre que la surexpression de PCDH7 accelerait la croissance tumorale et la formation de metastases pulmonaires par les cellules de cancer du colon. Dans l'ensemble, la recherche a permis de decouvrir que le knockdown de PCDH7 affecte l'autophagie et induit la ferroptose, renforcant ainsi la sensibilite des cellules cancereuses du colon a la chimiotherapie en reprimant l'axe MEKl/2/ERK/c-FOS. [Traduit par la Redaction] Mots-cles : PCDH7, MEK, ERK, cancer du colon, autophagie, ferroptose, Introduction Colon cancer, a prevalent malignancy in the digestive system, is a leading contributor to cancer-associated death (Ruan et al. 2020). Therapies for it mainly revolve around surgery, coupled with [...]