Li Qing-zhang

Morphological Changes to Early Stage Taenia solium Cysticerci Following Oxfendazole Treatment

The progressive morphological changes to early stage Taenia solium cysticerci following the treatment of pigs with a single therapeutic dose of oxfendazole (30 mg/kg), are described. On Day 1 after treatment, no obvious changes occurred in the general appearance of the larvae but alternations were seen by electron microscope, with an apparent reduction in the number of microtriches, and a complete disappearance of the tegument. Numerous granules were seen to have accumulated in the tegument cells. As treatment progressed, damage to the cysticerci was more serious and, by five days, all cysticerci were seen to be in an advanced stage of degeneration. By 45 days post-treatment, all cysts were calcified. These results suggest that oxfendazole is a highly effective drug against T. solium cysticerci in the early stages of development.

Proteomic Identification of Differentially Expressed Proteins in Vaccaria segetalis-treated Dairy Cow Mammary Epithelial Cells

To investigate the potential effects of Vaccaria segetalis, we employed the proteomic approach on the dairy cow mammary gland epithelial cells (DCMECs). A total of 35 differentially expressed nuclear proteins were visualized by 2-DE and silver nitrate staining. Of these, five proteins also displayed significant expression changes upon treatment of the water decoction from Vaccaria segetalis, and such alterations were further confirmed by RT-PCR. Together, at both the mRNA and protein levels, the water decoction from Vaccaria segetalis increased the expression of proteins ethylmalonic encephalopathy 1 (ETHE1), vesicle amine transport protein 1 homolog (VAT1), parkinson disease protein 7 homolog (Protein DJ-1), proteasome subunit alpha type-2 (PSMA2) and SUMO-activating enzyme subunit 1 (SAE1). This study would enable a better understanding of the molecular mechanisms underlying this water decoction effects at the protein level.

Expression and localisation of glucose transporter 1 (GLUT1) in dairy goat mammary gland at different physiological stages

Glucose is the major energy source for mammary epithelial cells, as well as an important substrate for lactose synthesis. Mammary epithelial cells take up glucose from extracellular fluid into the cell through glucose transporter (GLUT). This study was aimed at investigating the expression of GLUT1 glucose transporter in dairy goat mammary gland during puberty, pregnancy, lactation, and involution. Using real-time reverse transcription PCR (qRT-PCR) and Western blotting, we analyzed the expression of GLUT1 mRNA and protein in dairy goat mammary gland. GLUT1 mRNA and protein expression increased during pregnancy and lactation, especially at peak lactation, and decreased strongly after weaning. Furthermore, the location of GLUT1 protein was determined by immunofluorescence laser confocal microscopy. GLUT1 protein localised to the basal and apical plasma membrane of epithelial cells, and also in the cytoplasm. The results from this study showed that GLUT1 is expressed in the dairy goat mammary gland with the...

Effect of Different Roughages on Milk Protein and Milk Fat Synthesis in Dairy Cows

The main purpose of this study was to determine the effect of a corn straw or mixed diet on milk production, milk composition and the expression of genes associated with lactation in mid-lactation Chinese Holstein cows. In this study, 10 healthy Chinese Holstein cows were randomly assigned to two groups and fed with different diets respectively, corn straw (CS) or mixed forage (MF) diet. CS group was fed roughage consisting of 53.8% corn straw only and the forge to concentrate (F : C) ratio [dry matter (DM)] was about 40: 60. MF group was fed roughage consisting of 3.7% Chinese wildrye and 23.4% alfalfa hay, the forge to concentrate (F : C) ratio (DM) was 70: 30. All the cows were fed 8 weeks and body weight, dry matter intake, body condition score, fat, protein, lactose, milk yield, total solid and somatic cell count (SCC) were recorded. Quantitative real-time PCR (qRT-PCR) was used to analyze cow mammary gland samples representing two different diets. The results suggested that different diet types had significant effects on milk yield, lactose, milk fat, milk protein, dry matter intake and somatic cell count in dairy cows, and cows fed MF diet improved milk production and lactation performance clearly (P<0.05). In addition, mRNA expression of genes ACC, mTOR, STAT5, CSN2, PPARγ, FABP3 and PTEN in MF group was extremely significantly higher than that in CS group (P<0.05). mRNA expression of AKT1, FAS, SCD and SREBP1c in MF group was significantly higher than that in CS group (P<0.01). In summary, the milk yield and composition in mixed forage group were significantly improved than those in corn straw group.

Potential Genes for Regulation of Milk Protein Synthesis in Dairy Goat Mammary Gland

Abstract The lactating mammary gland is a prodigious protein-producing factory, but the milk protein synthesis mechanisms are not well understood. The major objective of this paper was to elucidate which genes and pathways were involved in the regulation of milk protein synthesis in the dairy goat mammary gland. Total 36 primiparous Guanzhong dairy goats were allotted in 12 groups according to their mammary development stages: days 90 and 150 of virgin, days 30, 90, and 150 of pregnancy, days 1, 10, 35, and 60 of lactation and days 3, 7, and 21 of involution (three animals per group). Mammary tissue RNA was isolated for quantitative real-time RT-PCR of four casein genes alpha-s1 casein (CSN1S1), alpha-s2 casein (CSN1S2), beta-casein (CSN2) and casein kappa (CSN3), four whey protein genes lactoglobulin (LGB), lactalbumin (LALBA), lactofarrin (LTF), and Whey acidic protein (WAP) and the genes which were potentially to regulate dairy goat milk protein synthesis at the level of transcription or translation [prolactin receptor (PRLR), AKT1, signal transducers and activators of transcription 5 (STAT5), E74-Like Factor 5 (ELF5), eukaryotic translation initiation factor 4E binding protein 1 (EIF4E-BP1), S6kinase (S6K) and caveolin 1]. The results showed that all genes were up-regulated in lactation period. The expressions of PRLR, AKT1, STAT5, ELF5, and S6K were similar to mRNA expressions of milk proteins. Our results indicated that milk protein synthesis in dairy goat mammary gland was possibly regulated by these genes.

Vaccaria segetalis activates cellular lactogenesis signaling pathway of dairy cow mammary epithelial cells in vitro

Vaccaria segetalis has very strong effect on lactogenesis, but the mechanism is still unknown. This study aims to reveal the influence of Vaccaria segetalis on cellular lactogenesis signaling pathway of dairy cow mammary epithelial cells (DCMECs). In this study the purified DCMECs was used to screen the most effective concentration of Vaccaria segetalis water decoction for lactogenesis. DCMECs were treated with prolactin (PRL), E (estrogen) or water extraction of Vaccaria segetalis, and many lactogenesis signal molecules in DCMECs including prolactin receptor (PRLR), estrogen receptor a (ERa), p-STAT5, p-mTOR, p100, GARS, PPARg and cyclinD1 were detected by using western blot assay. It was found that Vaccaria segetalis, E and PRL could promote lactogenesis of DCMECs and up-regulate these lactogenesis signal molecules except PPARg. These data reveals that Vaccaria segetalis has a similar role as E or PRL and activates cellular lactogenesis signaling pathway of DCMECs on both the translational and transcriptional levels.

Role of miRNA in Mammary Gland Development and Lactation

miRNA can regulate development and milk yield of the mammary gland through epigenetic mechanism. miRNA can directly and indirectly modulate the activity of the epigenetic machinery, target genes through post-inhibition of translation initiation, mediate miRNA decay, target genes and inhibit the positive regulation, regulate tone modification, and regulate DNA methylation of target genes. Here we reviewed the role of miRNAs in mammary gland development and lactation. Researching miRNA in mammary gland development and lactation process, and understanding the response of the epigenetic mechanisms to external stimuli will be an important necessity to devise new technologies for maximizing their activity and milk production in the dairy cow.

Proteomic Analysis of Nuclear Phosphorylated Proteins in Dairy Cow Mammary Epithelial Cells Treated with Prolactin

Abstract Prolactin (PRL) is a versatile signaling molecule and regulates a variety of physiological processes, including mammary gland growth and differentiation and the synthesis of milk proteins. While PRL is known to be necessary for high levels of milk protein expression, the mechanism by which the synthesis of milk proteins is stimulated at the transcript level is less known. A major modification in the transcript level is protein phosphorylation. To gain additional insights into the molecular mechanisms at the transcript level underlying PRL action on the dairy cow mammary epithelial cells (DCMECs), nuclear phosphoproteins whose expression distinguishes proliferating regulated by PRL in DCMECs were identified. A phosphoprotein-enriched fraction from nuclear proteins was obtained by affinity chromatography, and a two-dimensional gel electrophoresis (2-DE) and matrix assisted laser desorption/ionization time of matrix-assisted laser desorption/ionization/time of flight mass spectrometry (MALDI-TOF MS) were used to identify the changes of nuclear phosphoproteins in DCMECs treated with prolactin. Seven proteins displaying≥2-fold difference in abundance upon PRL treatment in DCMECs were identified by MALDI-TOF MS. The protein-GARS (GlyRS), which belonged to the class-II aminoacyl-tRNA synthetase family, played a global role in the milk protein synthesis. SERPINH1 (Heat shock protein 47), which was the first heat shock protein found to be a member of the serpin superfamily, regulated physiologic functions, such as complement activation, programmed cell death, and inflammatory processes. PRDX3, which belonged to a family of antioxidant enzymes, played an important role in scavenging intracellular reactive oxygen species (ROS). ACTR1A, belonged to the actin family, which was associated with transport of p53 to the nucleus. Annexin A2, a Ca 2+ -dependent phospholipid-binding protein, maintained the viability and cell cycle regulation of DCMECs. PSMB2 and PSMD10, which belonged to ubiquitin-proteasome system, were involved in several cellular processes, including cell cycle control, cellular stress response, intracellular signaling. This screening revealed that prolactin influenced the level of nuclear phosphoproteins in DCMECs. This result opens new avenues for the study of the molecular mechanism linked to the synthesis of milk proteins.

Impact of let-7g on Proliferation and Lactation of Mouse Mammary Epithelial Cells

let-7g, a member of the let-7 family, regulates gene expression at the post-transcriptional level. The study explored a series of biological effects of mouse mammary epithelial cells that let-7g was produced. The differential expression of let-7g was detected by qRT-PCR in different developmental stages of the mouse mammary gland. let-7g expression and impact of let-7g on mouse mammary epithelial cells were analyzed by CASY-technology, qRT-PCR, Western blotting and HPLC inhibited let-7g expression of mouse mammary epithelial cells through gene silencing. The results showed that qRT-PCR identified let-7g as being down-regulated in mouse mammary epithelial cells after it was inhibited. Mouse mammary epithelial cells with low expression of let-7g displayed higher expression of TGFβRⅠprotein than those with high expression of let-7g, suggesting that low let-7g expression contributed to TGFβRⅠover-expression. Finally, the expression of let-7g was down-regulated, which significantly enhanced the proliferation of mouse mammary epithelial cells, and increased expression of β-Casein. The data indicated that let-7g could negatively regulate the expression of target Tgfbr1 by complementary combination in mouse mammary epithelial cells, and then regulate the cell proliferation and expression of β-Casein by suppressing the TGFβRⅠexpression.

Screen of Bovine Mammary Gland Epithelial Cell Specifcity Promotor

Three lactoproteins (α-S1-casein, β-lactoglobulin, and β-casein) promotors were cloned, sequenced and compared relative luciferase expression. The results showed that the promotor activity of bovine α-S1-casein gene was the best, and would be used to produce pharmaceutically and medically important proteins in the mammary gland of transgenic animals and also for the construction of an inducible eukaryotic expression vector.