Bacterial biofilms are particularly problematic since they become resistant to most available antibiotics. Hence, novel potential antagonists to inhibit biofilm formation are urgent. Here the influences of two natural products, ursolic acid and resveratrol, on biofilm of the clinical methicillin-resistant Staphylococcus aureus (MRSA) isolate were investigated using RNA-seq, and the differentially expressed genes were analyzed using Cuffdiff. The results showed that ursolic acid inhibition of biofilm formation may reduce amino acids metabolism and adhesins expression and resveratrol may disturb quorum sensing (QS) and the synthesis of surface proteins and capsular polysaccharides. In addition, the transcriptome analysis of resveratrol and the combination of resveratrol with vancomycin inhibition of established biofilm revealed that resveratrol would disturb the expression of genes related to QS, surface and secreted proteins, and capsular polysaccharides. These findings suggest that ursolic acid and resveratrol could be useful to be adjunct therapies for the treatment of MRSA biofilm-involved infections.

Class I integrons were detected in 40.8% (40/98) of Pseudomonas aeruginosa strains and 52.8% (56/106) of Acinetobacter baumannii strains in the Nanjing area of China, including several cassette arrays not previously reported.The rapid dissemination of antibiotic resistance genes among bacterial isolates is an increasing problem in infectious disease. Recent studies have shown that a conserved DNA sequence, integron, may be carried on these episomal genetic structures (12,14). Integrons possess two conserved segments separated by a variable region that includes integrated cassettes, which often include antibiotic resistance genes (11). Many resistance genes are present as gene cassettes within integrons, which may themselves be located on transmissible plasmids and transposons (11). In China, resistance to various antibiotics is common in clinical isolates, often more so than in Western countries, especially among Pseudomonas aeruginosa and Acinetobacter baumannii isolates (7,8,16). However, the frequencies, characteristics, and roles of integrons and gene cassettes in the two species have not yet been investigated in a large-scale study.In order to study the roles of gene cassettes in the two species, we obtained 98 P. aeruginosa isolates and 106 Acinetobacter sp. isolates from four general hospitals in the Nanjing area of China during June 2003 and June 2005. The strains were randomly obtained from a variety of clinical specimens from diverse units of the four hospitals. All bacterial strains were identified by the analytical profile index procedure (API-20NE system; bioMerieux, France). Susceptibility to antimicrobial agents was tested by the disk diffusion method on Mueller-Hinton agar plates, according to Clinical and Laboratory Standards Institute guidelines (2). DNA used for PCR was prepared as described previously (9). All isolates were screened for integrons by PCR using degenerate primers hep35 (5Ј TGCGGGTYAARGATBTKGATTT 3Ј) and hep36 (5Ј CARCACATGCGTRTARAT 3Ј) and HinfI restriction analysis of the integrase gene product (18). Class I integron

Sterol regulatory element binding protein 1 (SREBP1; gene name SREBF1) is known to be the master regulator of lipid homeostasis in mammals, including milk fat synthesis. The major role of SREBP1 in controlling milk fat synthesis has been demonstrated in bovine mammary epithelial cells. Except for a demonstrated role in controlling the expression of FASN, a regulatory role of SREBP1 on milk fat synthesis is very likely, but has not yet been demonstrated in goat mammary epithelial cells (GMEC). To explore the regulatory function of SREBP1 on de novo fatty acids and triacylglycerol synthesis in GMEC, we overexpressed the mature form of SREBP1 (active NH2-terminal fragment) in GMEC using a recombinant adenovirus vector (Ad-nSREBP1), with Ad-GFP (recombinant adenovirus of green fluorescent protein) as control, and infected the GMEC for 48 h. In infected cells, we assessed the expression of 20 genes related to milk fat synthesis using real time-quantitative PCR, the protein abundance of SREBP1 and FASN by Western blot, the production of triacylglycerol, and the fatty acid profile. Expression of SREBF1 was modest in mammary compared with the other tissues in dairy goats but its expression increased approximately 30-fold from pregnancy to lactation. The overexpression of the mature form of SREBP1 was confirmed by >200-fold higher expression of SREBF1 in Ad-nSREBP1 compared with Ad-GFP. We observed no changes in amount of the precursor form of SREBP1 protein but a >10-fold increase of the mature form of SREBP1 protein with Ad-nSREBP1. Compared with Ad-GFP cells (control), Ad-nSREBP1 cells had a significant increase in expression of genes related to long-chain fatty acid activation (ACSL1), transport (FABP3), desaturation (SCD1), de novo synthesis of fatty acids (ACSS2, ACLY, IDH1, ACACA, FASN, and ELOVL6), and transcriptional factors (NR1H3 and PPARG). We observed a >10-fold increase in expression of INSIG1 but SCAP was downregulated by Ad-nSREBP1. Among genes related to milk fat synthesis and lipid droplet formation, only LPIN1 and DGAT1 were upregulated by Ad-nSREBP1. Compared with the Ad-GFP, the cellular triacylglycerol content was higher and the percentage of C16:0 and C18:1 increased, whereas that of C16:1, C18:0, and C18:2 decreased in Ad-nSREBP1 cells. Overall, the data provide strong support for a central role of SREBP1 in the regulation of milk fat synthesis in goat mammary cells.

Peroxisome proliferator-activated receptor-gamma (PPARG) is considered to be a central regulator of lipid metabolism in mammary cells. Adipose differentiation-related protein (ADRP), a member of PAT family (Perilipin, ADRP, TIP47 family), plays a key role in lipid accumulation in mammary gland. It has been found that PPARG significantly promoted lipid storage in goat mammary epithelial cells (GMEC), which was abolished after knockdown of ADRP gene. The results of real-time PCR, Western blot and luciferase reporter assay for goat ADRP promoter showed that ligand-activated PPARG up-regulated the ADRP gene expression and activity of ADRP promoter. Moreover, PPARG directly interacted with a PPRE (PPAR response element) spanning at -1003 to -990 on ADRP promoter. In this study, to our knowledge, we are the first to verify the function of PPARG on lipid storage on cellular level of goat mammary gland and our results revealed a novel pathway that PPARG may regulate lipid accumulation by controlling the expression of ADRP gene.