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Bovine mastitis is often taken as one of the most common diseases in dairy farms, which its pathophysiology leads to a reduction of milk production and its quality. The penetration of pathogenic bacteria into the mammary gland, through either a contagious or environmental approach, has been determined the way of infection. The mastitis derived bacteria have become a challenge in practice, since the increasing exposure of antimicrobial. In order to identify characteristics of the epidemiological regulation and drug resistance of the pathogenic bacteria of bovine mastitis in northern Jiangsu, 156 clinical mastitis milk samples were collected from 3 large-scale farms for the epidemiological investigation and analysis of the drug resistance of E. coli. The bacteria were positively isolated in a total of 143 milk samples. The results showed that 78 strains of E. coli were detected, with a prevalence rate of 26.99%, followed by 67 strains of K. pneumoniae, with a prevalence of 23.19%, and 38 strains of Staphylococcus, with a prevalence of spp. 13.15%. In addition, 78 strains of E. coli isolated from bovine mastitis were tested for susceptibility to 8 kinds of antibiotics. It was shown that gentamicin and tetracycline were the most effective against E. coli, with the susceptibility rate of 83.3%, followed by streptomycin and ciprofloxacin, with 73.1% and 71.8% respectively. However, β-lactams including penicillin, cefothiophene, and amoxicillin showed serious resistance to E. coli isolates. There were 12 drug resistance genes detected by PCR, including β-lactam (blaTEM, blaCTX-M, and blaSHV), aminoglycoside (armA and armB), tetracycline (tetA, tetB, and tetC), and quinolone (qnrS, qepA, oqxA, and oqxB) related genes. Notably, all E. coli isolates carried blaTEM gene (100%). The detection rate of blaCTX-M was 53.8%, followed by the detection of blaSHV (20.5%), armA (9.0%), tetA (26.9%), tetB (2.6%), tetC (20.5%), qnrS (29.5%), oqxA (37.2%) and oqxB (1.3%). The present study provides crucial information on the distribution of bovine mastitis derived bacterial pathogens in Jiangsu province, as well as highlighting the antimicrobial resistance which might help to improve the efficiency of antibiotics treatment on bovine mastitis. [ABSTRACT FROM AUTHOR]

In our study, four single nucleotide polymorphisms (SNPs) were identified in exon 2 of cofilin-1 (CFL1) gene in 488 Chinese Qinchuan (QC) cattle, which included two missense mutations T 2084G and G 2107C, two synonymous mutations T 2052C and T 2169C. Further, we evaluated haplotype frequency and linkage disequilibrium (LD) coefficient of four SNPs. At SNP T 2052C, G 2107C and T 2169C, the QC cattle population belonged to intermediate genetic diversity (0.25 < PIC-value < 0.5), whereas SNP T-2084G belonged to low polymorphism (PIC-value < 0.25). Haplotype analysis showed that 6 different haplotypes (frequency > 0.03). LD analysis showed that SNP G 2107C and T 2169C, SNP G 2107C and T 2084G were high LD, respectively (r2 > 0.33). Association analysis indicated that SNP T 2052C was significantly associated with body length, chest breadth, chest depth and body mass in the QC population (p < 0.01 or p < 0.05). SNP G 2107C was significantly associated with rump length (p < 0.05). SNP T 2169C was significantly associated with chest breadth and chest depth (p <.01 or p <.05). The results of our study suggest that the CFL1 gene may be a strong candidate gene that affects growth traits in the QC cattle breeding program. [ABSTRACT FROM AUTHOR]

As the main component of the Gram-negative bacterial cell wall, lipopolysaccharide (LPS) is well documented as an inducer of inflammation in bovine mammary cells. Lycium barbarum (goji) polysaccharides (LBP) have been used in nonruminants as prebiotics to improve growth performance, immune ability, and antioxidant capacity. We aimed to investigate the underlying effects of LBPs on proinflammatory responses in LPS-stimulated primary bovine mammary epithelial cells (bMECs). Cells were isolated from mammary tissue of three lactating Holstein cows without clinical disease (30.26 ± 3.1 kg/d of milk yield; 175 ± 6 DIM). For the pre-experimental treatment, bMECs were precultured with serum-free medium for 12 h. Treatments were as follows: pretreatment with culture medium devoid of LPS or LBP for 30 h (CON); CON for 24 h followed by challenge with 2 μg/mL LPS for 6 h (LPS); pretreatment with 100 or 300 μg/mL LBP for 24 h followed by LPS challenge (2 μg/mL) for 6 h (LBP(100)+LPS; LBP(300)+LPS). To further determine if the effect of LBP on immuneregulation is peroxisome proliferator-activated receptor-γ (PPARγ) activation dependent, an inhibitor of PPARγ, GW9662, at a concentration of 1 μM was used. Cells treated with LBP at 100, 300, and 500 μg/mL had upregulated protein abundance of PPARγ, while PGC1α had a higher expression only at 300 μg/mL of LBP treatment. Compared with CON, cells pretreated with LBP at 100 and 300 μg/mL had greater protein abundance of SCD1 and SREBP1. 5-Ethynyl-2′-deoxyuridine (EdU) staining and cell wound healing assays showed that the negative effect of LPS alone on cell proliferation was reversed by pretreatment with LBP at both 100 and 300 μg/mL. Upregulation of gene and protein abundance of proinflammatory factors and cytokines (COX-2, NLRP3, TNF-α, IL-1β, and IL-6) induced by LPS stimulation were alleviated by LBP pretreatment at 300 μg/mL (more than 2-fold decrease). Compared with LPS challenge alone, phosphorylation of proteins involved in NF-κB (IκBα and p65) and MAPK (p38, JNK, and ERK) pathways was downregulated following LBP treatment. Additionally, inhibition of PPARγ by GW9662 weakened the protective effect of LBP on LPS-induced protein abundance of phosphorylated p65, COX-2, IL-1β, and TNF-α. These results indicated that the protective effect of LBP on LPS-induced bMECs inflammatory responses is PPARγ activation-dependent. As such, this knowledge might help design strategies for intervening against the detrimental effects of bovine mastitis. Interpretive summary Current research examined Lycium barbarum polysaccharides (LBP) for combating LPS-induced inflammatory responses in primary bovine mammary epithelial cells. We uncovered a preventive role of LBP in reducing detrimental effects induced by LPS including inhibition of NF-κB and MAPK along with peroxisome proliferator-activated receptor-γ (PPARγ) activation. The decrease in cell proliferation due to LPS was curtailed by pretreatment with LBP. Moreover, the effect of LBP on regulation of inflammatory responses in bovine mammary epithelial cell was PPARγ dependent. Collectively, data suggest that LBP reverses LPS-induced inflammatory response via MAPK/NF-κB signaling in a PPARγ-activation-dependent manner. Thus, the study provides new insights into therapeutic strategies for combating mastitis using LBP and highlighted the link between PPARγ and regulation of mammary cell inflammation. [ABSTRACT FROM AUTHOR]

Polyimide (PI) foams have been developed for decades and widely used as thermal insulation materials. However, the limited mechanical and thermal properties continually being a serious problem that restrict their further applications. In this study, a series of rigid PI foams with excellent mechanical and thermal performance were fabricated by the reaction of benzophenone-3,3',4,4'-tetracarboxylic dianhydride (BTDA) with two diamines of 2–(4-aminophenyl)-5-aminobenzimidazole (BIA) and 4,4'-diaminodiphenyl ether (ODA) with various molar ratios, and the cis-5-norbornene-endo-2,3-dicarbox-ylic acid (NA) was introduced as end-capping and foaming agent. The results demonstrate that the foaming degree decreases with increasing the BIA molar ratio in the polymer chains owing to the elevated melt viscosity of precursor. Furthermore, the prepared rigid PI foams exhibit excellent thermal and mechanical properties. When the BIA contend up to 40 mol%, the glass transition temperature (Tg) and the temperature at 10% of weight loss (Td 10 %) of PI foam increased ∼80°C and ∼35°C in comparison with the pristine PI-0, respectively. In addition, the compressive strength and modulus at 10% strain of PI-4 reached to 5.48 MPa and 23.8 MPa, respectively. For the above-mentioned advantages, the prepared rigid PI foams are promising candidates as thermal insulation and structure support composite materials in the aerospace and aviation industries. [ABSTRACT FROM AUTHOR]