Potential output and risk of commonly administered veterinary antibiotics from small-scale livestock farms to surrounding areas in Northwest China.

The concern over antibiotic pollution from animal husbandry has significantly increased over recent years. However, few studies on output and environmental risk of veterinary antibiotics (VAs) throughout different exposure matrices from small-scale livestock farms (SSLFs) have been explored. This study explored the output and environmental risk of three classes of VAs (sulfonamides (SAs), tetracyclines (TCs), fluoroquinolones (FQs)) in three different types of environmental media (manure, soil, and plants/vegetables) derived from four livestock feedlots in the Hexi Corridor of Northwest China. Following, a risk assessment was conducted to identify the hazardous potential of these VAs on the ecological health of the surrounding environment. A total of 108 soil, 36 manure, 12 plants/vegetables, and 15 animal product samples were collected from the animal feedlots for analysis. The results showed that each of the three groups of VAs were detected in the soil, manure and plant samples derived from all four feedlots in varying levels. In the soil samples, the detection rate of SAs (68%) was higher than the TCs (57%) and the FQs (27%). The total concentration of VAs ranged from not detected (n.d.) to 275 ng/g, while chlortetracycline (CTC) was the most abundant (275 ng/g) of the VAs in soil samples. The SAs had the highest detection rate (100%), followed by TCs (89%), and FQs (78%) in manure samples. The total concentration of VAs residues ranged from n. d. to 105 ng/g, of which CTC was as high as 91 ng/g in manures. In the plant/vegetable samples, the TCs had the highest detection rate (58%), while sulfamethazine (SDM) was the most abundant (32 ng/g). The total concentration of the VAs ranged from n. d. to 65 ng/g in the plant/vegetable samples. The target VAs were not detected in animal products. Measurements of the composition of VAs in soil samples at different vertical depths as well as horizontal distances from the manure accumulation sites showed that VAs were partially retained in the soil of the feedlots and were distributed into the surrounding environment both horizontally and vertically. It is suspected that the detected VAs could be accumulated in agricultural soils since they could be found in most of the sampled manures and soils in SSLFs. These results highlighted the necessity of considering SSLF practices to mange the accumulation and disposal of manure mitigating and controlling VA pollution.

Status, Sources and Potential Risk of Polycyclic Aromatic Hydrocarbons in Soils from Hexi Corridor in Northwest China.

The Hexi Corridor is the main commodity grain base in northwest China and plays a special role in ensuring food security in northwest China. However, the multiple pollution transport pathways of PAHs and complex and co-existing potential pollution sources around the study areas require a combination of pollution status, source identification, and risk assessment to explore pollution distribution and potential risks. In this study, the total PAHs concentration (∑18PAHs) in soils ranged from 69.6 to 1300 ng/g. Spatially, the higher content of PAHs was detected in the Jinchang, followed by Jiayuguan, Jiuquan, Wuwei, and Zhangye, indicating a remarkable influence of different industrial activities. Although high-molecular-weight PAHs were predominated, the compositions of PAHs in most of the soil samples were varied. The isomer ratios of PAHs and principal component analysis were also revealed the PAHs probably originate from the sources different significantly. The total health risk values indicated a low health risk.

Single and competitive sorption of sulfadiazine and chlortetracycline on loess soil from Northwest China☆.

The fate of veterinary antibiotics (VAs) in soil environment is determined by the hydrophilic performance and solubility of VAs and the type of soil. In this study, sulfadiazine (SDZ) and chlortetracycline (CTC) were selected as target pollutants, and a batch sorption method was used to find out the single and sorption competitive behavior and mechanism of the target pollutants on loess soil. Kinetic studies showed the apparent sorption equilibrium was reached 0-6 h for CTC and 0-12 h for SDZ. The sorption kinetics of VAs on loess soil were fitted well with a pseudo-second order kinetic model. Sorption thermodynamic data indicated the isotherm sorption of both SDZ and CTC on loess soil was fitted well with Freundlich isothermal (R2, 0.960-0.975) and linear models (R2, 0.908-0.976). The sorption affinity of CTC (Kd, 290-1620 L/kg for CTC) was much greater than that of SDZ (Kd, 0.6-4.9 L/kg for SDZ). The results also suggest that SDZ may be easily mobilized or leached from loess soil at neutral and alkaline pH, while CTC may be easily mobilized or leached at neutral pH. The sorption of each single target pollutant on the outer layer complex decreased with increasing ionic strength. Higher initial concentrations resulted in greater sorption capacity of target pollutants on loess soil increased. The sorption capacities of CTC and SDZ in the mixed system were lower than the sorption capacity of each single system, showing a competitive sorption behavior of CTC and SDZ during the sorption process. Overall, CTC showed the highest sorption potential in loess soil, whereas SDZ showed a high leaching risk in loess soil. These findings contribute to understanding the fate of different VAs in loess in the natural environment.

Ankyrin exposure induced by activated protein kinase C plays a potential role in erythrophagocytosis.

BACKGROUND: In physiological and pathological conditions activated protein kinace C (PKC) has been observed in the erythrocytes. Externalization of ankyrin followed by Arg-Gly-Asp (RGD)/integrin recognition also triggers erythrophagocytosis. In the present study, to test whether activated PKC is associated with ankyrin exposure in erythrophagocytosis. METHODS: Phorbol 12-myristate-13-acetate (PMA)-induced PKC activation and ankyrin phosphorylation were tested, and under different treatment conditions the subpopulation of erythrocytes with ankyrin exposure and the levels of intracellular calcium were analyzed by flow cytometry. RESULTS: Results showed that treatment of erythrocytes with PMA in a calcium-containing buffer led to ankyrin exposure. In the absence of extracellular calcium, no ankyrin exposure was observed. PKC inhibition with calphostin C, a blocker of the PMA binding site, completely prevented the calcium entry, protein phosphorylation and ankyrin exposure. PKC inhibition with chelerythrine chloride, an inhibitor of the active site, diminished the level of ankyrin-exposing cells and ankyrin phosphorylation; however it even led to a higher percentage of cells with increased levels of calcium than with PMA treatment alone. Although PKC was activated and ankyrin phosphorylation occurred, no ankyrin exposure was observed in the absence of extracellular calcium. CONCLUSION: Analyses of results suggested that PMA induces calcium influx into the erythrocytes, leading to the activation of calcium-dependent enzymes and the phosphorylation of membrane proteins, ultimately inducing ankyrin exposure and erythrophagocytosis. This study may provide insights into the molecular mechanisms of removing aged or diseased erythrocytes.

[Increased oxidative damages of erythrocytes caused by declined blood oxygen saturation].

This paper was to explore the effect of blood oxygen saturation (SO2) on oxidative damages of erythrocytes under the condition of oxidative stress. Keeping SO2 of cultured erythrocytes in vitro at the states of 0.3, 0.5, 0.7, 0.9 and 0.98, respectively, we induced oxidative stress by tert-buthylhydroperoxide (BHP, 0.15 mmol/L of final concentration). After incubation, antioxidant capacity was assessed by measuring content of reduced glutathin hormone (GSH) in erythrocytes. Methemoglobin (MetHb) content, lipid peroxidation (thiobarbituric acid-reactive substances, TBARS) and denatured globin-chains on the plasma membrane were measured to assess the extent of oxidative damages. The results showed that in the presence of BHP, GSH contents increased from 0.3 to 0.98 groups; MetHb, TBARS and globin-chains levels all dropped with the rise of SO2. In conclusion, antioxidant capacity and oxidative damages of erythrocytes are closely related to SO2, declined SO2 could promote oxidative damages of erythrocytes.