Alteration of somatostatin receptor 2 expression in canine mammary gland tumor

Somatostatin receptor 2 (SSTR2) is a negative regulator of cell proliferation in human breast cancer. Since there is little information about SSTR2 in canine mammary gland tumor (MGT), we clarified its distribution and expression level in normal mammary gland, benign MGT and malignant MGT. SSTR2 expression determined by immunohistochemical staining was observed in the cytoplasm of luminal epithelial cells. The intensity was negatively correlated with malignancy: normal tissues and some of the benign tumors had the highest levels, while the malignant tumors had little or no SSTR2 expression. As for the Western blotting, SSTR2 protein level in benign tumors was significantly lower than the normal mammary gland. On the other hand, SSTR2 protein levels in two of three malignant tumors were higher than the other groups. These results suggest that SSTR2 expression alters according to the malignancy of canine MGT.     

Genetic characterization of bovine viral diarrhea virus strains in Beijing,China and innate immune responses of peripheral blood mononuclear cells in persistently infected dairy cattle

To acquire epidemiological data on the bovine viral diarrhea virus (BVDV) and identify cattle persistently infected (PI) with this virus, 4,327 samples from Holstein dairy cows were screened over a four-year period in Beijing, China. Eighteen BVD viruses were isolated, 12 from PI cattle. Based on genetic analysis of their 5''-untranslated region (5''-UTR), the 18 isolates were assigned to subgenotype BVDV-1m, 1a, 1d, 1q, and 1b. To investigate the innate immune responses in the peripheral-blood mononuclear cells of PI cattle, the expression of Toll-like receptors (TLRs), RIG-I-like receptors, interferon-α (IFN-α), IFN-β, myxovirus (influenza virus) resistance 1 (MX1), and interferon stimulatory gene 15 (ISG15) was assessed by qPCR. When compared with healthy cattle, the expression of TLR-7, IFN-α, and IFN-β mRNA was downregulated, but the expression of MX1 and ISG-15 mRNA was upregulated in PI cattle. Immunoblotting analysis revealed that the expression of interferon regulatory factor 3 (IRF-3) and IRF-7 was lower in PI cattle than in healthy cattle. Thus, BVDV-1m and 1a are the predominant subgenotypes in the Beijing region, and the strains are highly divergent. Our findings also suggest that the TLR-7/IRF-7 signaling pathway plays a role in evasion of host restriction by BVDV.     

Effect of lactoferrin on murine embryo development created from lipopolysaccharide-treated sperm

The effect of lactoferrin (LF) on embryo development was investigated by using lipopolysaccharide (LPS)-treated mouse sperm. For the development rate of the 2-cell stage embryo, the embryo derived from LPS- and LF-treated sperm showed similar survival rate to the control embryo. On day 12 after the embryo transfer into the recipient, the frequent abnormality was observed in the embryo derived from LPS-treated sperm, and the abnormality was tended to be inhibited in the embryo derived from LPS- and LF-treated sperm. These results imply that LF treatment on sperm contaminated with bacteria may facilitate the embryo development, which contribute to the improvement of infertility.     

基于田块尺度的农田土壤重金属污染评价及来源解析

基于田块尺度采集农田表层土壤样品120件,采用绝对因子分析/多元线性回归（APCS-MLR）受体模型与地统计学分析对研究区域内As、Cd、Cu、Cr、Mn、Ni、Pb和Zn这8种重金属污染空间分布特征及来源进行解析,利用地累积指数和潜在生态风险指数法评价土壤生态风险。研究结果表明：研究区表层土壤中8种重金属含量差异较大,As、Cd和Cr点位超标率分别为61.83%、90.83%和92.52%,土壤重金属Zn、Cu、Cr和Ni主要以残渣态存在（占比在80%以上）。土壤中Cd、Cr和Cu含量空间分布格局呈东南部较高、中部次之、西北部较低的趋势,而Mn、Ni、Pb和Zn含量的空间分布格局与此相反。APCS-MLR模型表明研究区域土壤重金属As、Cr、Cu和Ni的来源以自然源为主,占比分别为39.34%、47.32%、44.53%和50.23%; Pb、Zn的来源以工业活动源和交通源为主,占比分别为31.93%、30.53%和23.36%、22.17%; Cd的农业活动源占比为53.63%。土壤pH与有效态As、Cd、Cu和Ni含量呈极显著负相关性（P<0.01）,土壤有机质与有效态As、Cd和Cr呈极显著负相关性（P<0.01）。地累积指数显示土壤Cr总体处于中、重度污染水平,其次是Cd;生态危害指数也表明Cr和Cd是主要生态危害元素,潜在生态危害系数变化范围分别为5.20~41.12和11.56~113.35。总体来看,研究区域Cr和Cd污染较为严重,存在潜在风险,应采取安全利用和修复等措施,降低其风险水平。     

Molecular cloning and functional analysis of duck Toll-like receptor 5

Toll-like receptor 5 (TLR5) is responsible for the recognition of bacterial flagellin in vertebrates. In this study, we cloned the single-exon TLR5 gene of the Maya breed of Common Shelduck (Tadorna tadorna). The TLR5 open reading frame is 2580 bp in length and encodes an 859-amino acid protein. The putative amino acid sequence of duck TLR5 consisted of a signal peptide sequence, 11 leucine-rich repeat domains, a leucine-rich repeat C-terminal domain, a transmembrane domain, and an intracellular Toll-interleukin-1 receptor domain. The duck TLR5 gene was highly expressed in the lung, bone marrow, spleen, and liver; moderately expressed in kidney, small intestine, large intestine, and brain. A plasmid expressing duck TLR5 was constructed and transfected into HEK293T cells, and expression was confirmed by indirect immunofluorescence assay. HEK293T cells transfected with duck TLR5- and NF-κB-luciferase-containing plasmids significantly responded to flagellin from Salmonella typhimurium, indicating that it is a functional TLR5 homolog.     

The fate of chlortetracycline residues in a simulated chicken–fish integrated farming systems

Two experiments were conducted at the Asian Institute of Technology, Pathumthani, Thailand to investigate the fate of chlortetracycline (CTC) residue in chicken manure and its effect on integrated chicken–fish farming system. During the first experiment, broiler chickens were raised and CTC residues in their manure were analysed. Chicken fed diets containing 0, 50, 200 and 800 CTC mg kg^?1 had CTC residue levels of 0, 0.9, 3.8 and 6.5 CTC ng g^?1. Once the diet containing CTC was withdrawn, CTC in the manure dropped to negligible amounts (0, 0, 0.2 and 0.5 CTC ng g^?1) within 1 day. Integrated chicken–fish farming systems were simulated during the second experiment to determine the fate of antibiotic residues in chicken manure in aquaculture environment. Chickens were fed a CTC‐free diet and a feed containing CTC at 200 mg kg^?1. Ten 4 m³ square concrete tanks (2 × 2 × 1 m) were used for the experiment. Five tanks were fertilized with CTC‐contaminated manure and the remaining five tanks were fertilized with CTC‐free manure at a rate of 100 kg dry matter ha^?1 day^?1. Sex‐reversed Nile tilapia (Oreochromis niloticus) was stocked at 12 fish tank^?1 on the 14th day after chicken manure application. The immuno‐radio microbial receptor assay (Charm II test) revealed that edible fish muscle, fish intestinal tract and sediment were contaminated by CTC at rates of 7.21, 22.104 and 1.788 ng g^?1, respectively, after 45 days. Chlortetracycline was detected on day 20 in the water column and gradually increased from 0.26 to 12.13 ng g^?1. Chlortetracycline residues were not detected in fish or the aquatic environment of the CTC‐free treatment. The results demonstrate the potential for antibiotic residue accumulation in fish and aquatic environment when CTC‐contaminated chicken manure is used for pond fertilization.     

Electromechanical effects of acetylcholine on the atrial tissues of the cultured tilapia (Oreochromis nilotica × O. aureus)

The effects of acetylcholine (ACh) on the action potential and twitch force of atrial tissues isolated from 15 tilapia (Oreochromis nilotica × O. aureus) were studied by means of conventional microelectrode techniques. In isolated whole atrium or sinoatrial tissue, scattered pacemaker-like cells with spontaneous diastolic depolarization were found mainly near the sinoatrial junction but also occasionally throughout the atrial wall. However, most of the atrial cells recorded were myocardial fibers as judged by a stable diastolic potential and a markedly reduced action potential duration (APD) in response to low concentrations of ACh (0.1–1 M). The shortening in APD in atrial myocardial fibers was correlated with a significant fall in twitch force in the atrial preparations. ACh at high concentrations (10–300 M) decreased moderately the APD and the slope of diastolic depolarization of the pacemakers and prolonged the spontaneous cycle length but did not induce hyperpolarization. The negative chronotropic action of ACh was competitively inhibited by atropine, a muscarinic antagonist. The means (± SEM) negative logarithm of the dissociation constant (pK_b or pA₂ value) for atropine against the ACh action on muscarinic receptors were 9.10 (± 0.13) (n = 6), similar to those values obtained in mammalian atria. The present findings indicate that while the negative inotropic effects of ACh in tilapia atria are comparable to those observed in mammalian hearts, unique electrophysiological responses to ACh exist in different types of tilapia atrial cells.