Propionate enhances the expression of key genes involved in the gluconeogenic pathway in bovine intestinal epithelial cells.

Approximately 15 to 50% of short-chain fatty acids (SCFA) reach the ruminant small intestine. Previous research suggests that activation of small intestinal gluconeogenesis induced by propionate has beneficial effects on energy homeostasis. However, the regulatory effect of propionate on key gluconeogenic genes in enterocytes of the bovine small intestine remains less known. Therefore, the purpose of this study was to establish the long-term cultures of bovine intestinal epithelial cells (BIEC) from bovine jejunum tissue using SV40T (1:200; Santa Cruz, Shanghai, China) and investigate the regulatory effect of propionate on the key gluconeogenic genes in BIEC. Our study showed that long-term BIEC cultures were established by SV40T-induced immortalization. Immortal BIEC were distinguished by the expression of cytokeratin 18, villin, fatty acid binding protein 2, and small intestine peptidase. The mRNA expression of genes involved in the SCFA transporters, monocarboxylate transporter 4, and Na+/H+ exchanger isoforms 1 were significantly elevated with 20 mM SCFA compared with untreated controls. In addition, BIEC exhibited significant uptake of propionate and butyrate from the culture medium. Remarkably, 3 mM propionate induced profound changes in mRNA level of key genes involved in gluconeogenesis, including phosphoenolpyruvate carboxykinase 2, pyruvate carboxylase, fructose-1,6-bisphosphatase 1, and peroxisome proliferator-activated receptor-γ coactivator 1α. Additionally, 3 mM propionate enhanced the expression of PGC1A mRNA at 3, 6, 12, and 24 h of incubation. These findings suggest that propionate controls the mRNA expression of genes involved in key enzymes for gluconeogenesis in the enterocytes of bovines.

Optimization of low-abundance protein extraction and abundant protein removal from defatted soybean meal.

The aim of this study was to optimize the conditions for the extraction of low-abundance proteins (LAPs) and the removal of abundant proteins (APs; ß-conglycinin and glycinin) from soybean meal. Single factor and orthogonal experiments were designed to determine the effects of four factors (isopropanol concentration, total extraction time, ultrasonic power, and ultrasonic time) on protein concentration in isopropanol extracts. Proteins in the isopropanol supernatant and the cold acetone precipitate of isopropanol were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS). The results showed that the optimal conditions were 50% isopropanol, ultrasonic pretreatment for 15 min at 350 W, and a total extraction time of 1 h. Under these conditions, the protein concentration in the isopropanol extracts reached 0.8081 g/L. Many LAPs were detected, including ß-amylase, soybean agglutinin, soybean trypsin inhibitor, fumarylacetoacetase-like, phospholipase D alpha 1-like, oleosin, and even some unknown soybean proteins. The soybean APs (ß-conglycinin and glycinin) were not found. The method may be useful for discovering new soybean proteins and extracting enough LAPs of soybean to allow further studies of their physiological effects on animals without the influence of APs.

Effects of alfalfa flavonoids extract on the microbial flora of dairy cow rumen.

OBJECTIVE: The effect of flavonoids from alfalfa on the microbial flora was determined using molecular techniques of 16S ribosome deoxyribonucleic acid (rDNA) analysis. METHODS: Four primiparous Holstein heifers fitted with ruminal cannulas were used in a 4×4 Latin square design and fed a total mixed ration to which alfalfa flavonoids extract (AFE) was added at the rates of 0 (A, control), 20 (B), 60 (C), or 100 (D) mg per kg of heifer BW. RESULTS: The number of operational taxonomic units in heifers given higher levels of flavonoid extract (C and D) was higher than for the two other treatments. The Shannon, Ace, and Chao indices for treatment C were significantly higher than for the other treatments (p<0.05). The number of phyla and genera increased linearly with increasing dietary supplementation of AFE (p<0.05). The principal co-ordinates analysis plot showed substantial differences in the microbial flora for the four treatments. The microbial flora in treatment A was similar to that in B, C, and D were similar by the weighted analysis. The richness of Tenericutes at the phylum level tended to increase with increasing AFE (p = 0.10). The proportion of Euryarchaeota at the phylum level increased linearly, whereas the proportion of Fusobacteria decreased linearly with increasing AFE supplementation (p = 0.04). The percentage of Mogibacterium, Pyramidobacter, and Asteroleplasma at the genus level decreased linearly with increasing AFE (p<0.05). The abundance of Spirochaeta, Succinivibrio, and Suttonella at the genus level tended to decrease linearly with increasing AFE (0.05

Establishment of primary bovine intestinal epithelial cell culture and clone method.

The aim of this study was to establish bovine intestinal epithelial cell (BIEC) line and provide a novel clone cell method. Although various strategies of bovine cell culture and clone techniques have been reported, these methods remain not established. Here, we culture successfully primary BIECs and establish a novel clone cell method. Our result showed that BIECs could be successfully cultured and passaged about generation 5. These cellular aggregates and clusters were adherent loosely at day 2 of culture. Cell aggregates and clusters start to proliferate after approximately 4 d. The BIECs showed positive reaction against cytokeratin 18, E-cadherin, and characteristics of epithelial-like morphology. In addition, the fatty acid-binding proteins (FABPs), villin, and intestinal peptidase (IP) band were positive in BIECs. Our results suggest that the establishment of culturing and clone BIEC methods will apply to isolate and clone other primary cells. These BIECs could therefore contribute to the study of bovine intestinal nutrient absorption and regulation, immune regulation, and the pathogenesis of the bovine intestinal disease, which will provide intestinal cell model in vitro.

Biological characterization of bovine mammary epithelial cell lines immortalized by HPV16 E6/E7 and SV40T.

Primary bovine mammary epithelial cells are not ideal models for long-term studies, because primary cells undergo a limited number of proliferations in vitro and enter into a growth-arrest stage called cell replicative senescence; we therefore must establish the immortalized bovine mammary epithelial cells (BMECs) in vitro. More importantly, the mechanisms of the relationship between immortalized and apoptotic cell remain unknown in BMECs. We therefore sought to elucidate the mechanisms of which immortalized cells escape the pathway of apoptotic signal. These cells were successfully immortalized without any signs of senescence. The maximum number of BMEC and E6E7 immortalized cells were reached after 6 d of culture. At this point, there were significantly more E6E7 immortalized cells than primary BMECs (P < 0.01). The population-doubling times of the E6E7 and SV40T immortalized cells were lowest at 48 and 72 h. We failed to detect the expression of the epithelial cell marker E-cadherin in BMECs; however, immortalized cells had low expression of E-cadherin. The expression of ß-catenin was markedly expressed in immortalized cells than in BMECs (P < 0.01). Caspase-3, caspase-9, and poly ADP-ribose polymerase (PARP) were detected; however, the cleavage of caspase-3 and PARP was not observed. Our data demonstrate that the expressions of caspase-9, caspase-3, and PARP are not sufficient for the apoptosis of immortalized cells and suggest that E-cadherin and ß-catenin might be an important indicator of the development of cancer.

[Significance of serum vascular endothelial growth factor test before radiotherapy in patients with nasopharyngeal carcinoma].

OBJECTIVE: To study the changes of serum vascular endothelial growth factor (VEGF) and beta 2-microglobulin levels before and after radiotherapy in 58 patients with nasopharyngeal carcinoma (NPC), and to elucidate the clinical significance of VEGF and beta 2-microglobulin test before radiotherapy. METHODS: Serum VEGF level was measured by sandwich ELISA in 58 patients with NPC and 24 healthy individuals, and the serum beta 2-microglobulin was assayed with time-resolved fluoroimmunoassay. RESULTS: The serum VEGF level in patients with NPC was (174.0+/-130.0) ng/L, higher than (134.1+/-66.6) ng/L of the healthy subjects, but the difference was not significant (P>0.05). The serum VEGF level was higher in T4 and IV a patients with NPC. No significant differences in the levels of serum VEGF were found among various N classifications in the patients with NPC. Patients with the serum VEGF level higher than 267.3 ng/L (mean+2 s of the serum VEGF level in the healthy individuals) had a shorter metastasis-free survival time (P<0.05). Although the patients with high beta 2-microglobulin level had a shorter survival time, the difference was not significant. CONCLUSION: The NPC patients with high serum VEGF level have a poor prognosis.