广州地区芥蓝、菜心和普通白菜中丙环唑和矮壮素残留及膳食暴露风险

为探明广州地区丙环唑和矮壮素在叶菜的残留以及膳食暴露风险情况,对2016年第2季度广州市9个区农贸市场和超市的芥蓝、菜心和普通白菜样品中丙环唑和矮壮素残留水平进行了分析。应用点评估和基于@Risk评估软件的概率评估方法 ,对这3种蔬菜中丙环唑和矮壮素残留膳食暴露风险进行了研究。结果显示,芥蓝、菜心、普通白菜中丙环唑残留均值为0.162 8~0.002 8 mg/kg,最高为芥蓝,与菜心和普通白菜差异显著,平均检出率为100%~70.25%,最高为芥蓝,与普通白菜差异显著。矮壮素残留平均值为0.010 9~0.001 0 mg/kg,最高为菜心,三者间差异不显著,平均检出率为14.99%~8.46%,最高为芥蓝,三者间差异不显著。通过膳食摄入3种蔬菜,丙环唑残留暴露急性风险熵为1.81~7.93,99%人群暴露慢性风险熵为1.02~25.03,0.1%人群存在芥蓝丙环唑膳食暴露慢性风险;矮壮素残留暴露急性风险熵为55.14~62.26,100%人群暴露慢性风险熵为3.26~8.11。3种蔬菜中丙环唑和矮壮素残留膳食暴露风险在可接受范围。     

Serologically defined Rhipicephalus (Boophilus) microplus larval antigens in BmLF3, a partially pure Sephacryl S-300 fraction of crude larval proteins

This report is designed to provide additional information regarding larval soluble proteins toward the planned development of a comprehensive database of Rhipicephalus (Boophilus) microplus proteins that elicit a humoral immune response in cattle as a result of natural ectoparasite infestation. Larval proteins of R. microplus are complex and the protein profile is not dominated by any major proteins. This report focuses upon an S-300 Sephacryl (molecular sieve) column fraction, fraction 3 (BmLF3). With the use of SDS-PAGE (without-2ME) and Western blotting with a composite pool of pre- and post-R. microplus larval infestation antiserum BmLF3 was found to contain 7 apparent common ixodid major antigens (207.3, 171.9, 98.0, 86.5, 65.7, 58.9, and 38.0 kDa), those potentially shared with other ixodid species, and 2 apparent R. microplus specific antigens evidenced by low-level antibody binding in crude BmLF3 (149.4 kDa) and HPLC peak 8 of BmLF3 (116.0 kDa). In addition, BmLF3 contains potent inhibitors of trypsin activity. However, these inhibitors of trypsin did not appear to elicit host antibodies as a result of natural ectoparasite exposure, as defined by Western blotting of reduced and denatured trypsin binding proteins purified by affinity chromatography.     

Evaluating the public health response to a mass bat exposure—Wyoming, 2017

Mass bat exposures (MBEs) occur when multiple people are exposed to a bat or a bat colony, often over an extended period. In August 2017, a public health investigation was started in response to an MBE that occurred during May–August 2017 at a national park research station in Wyoming. We identified 176 people who had slept primarily in two lodges (Lodges A and B) at the research station, and successfully contacted 165 (93.8%) of these individuals. Risk assessments (RAs) were administered to all 165 individuals to determine degree and type of exposures to bats (e.g., biting or scratching). Exposure status for research station guests was classified as “non‐exposed,” “low risk” or “high risk,” and counselling was provided to guide post‐exposure prophylaxis (PEP) recommendations. Prior to public health notification and intervention, 19 persons made the decision to pursue PEP. The healthcare‐seeking behaviours of this group were taken to represent outcomes in the absence of public health intervention. (These persons received a RA, and their risk classification was retrospectively assigned.) Approximately 1–2 weeks after conducting the RAs, we conducted a follow‐up survey to determine whether recommendations regarding PEP were ultimately followed. The proportion of individuals that unnecessarily pursued PEP was higher among the 19 individuals that sought health care prior to receiving the RA (p < 0.00001). Among those receiving the RA first, all persons classified as high risk followed public health guidance to seek PEP treatment. Despite this, upon re‐interview, only 21/79 (26.6%) of guests could accurately recall their risk classification, with most people (55.7%) overestimating their risk. Study findings demonstrate that early public health interventions such as RAs can reduce unnecessary use of PEP and that messaging used during rabies counselling should be clear.     

Effects of chronic hypobaric hypoxia exposure on dendritic spine morphological changes and filamin-A expression in neurons of mouse hippocampal CA1 region

AIM:To investigate the effects of hypobaric hypoxic exposure on the morphological changes of dendritic spines and the expression of filamin-A in the neurons of mouse hippocampal CA1 region. METHODS:C57BL/6 male mice (6~8-week-old) were divided into normoxia 7 d group, normoxia 14 d group, hypobaric hypoxia 7 d group and hypobaric hypoxia 14 d group. The mice in hypobaric hypoxia exposure groups were placed in a hypobaric chamber with hypobaric hypoxia exposure to simulate the plateau at an altitude of 6 000 m. Golgi staining assay was used to observe the branch number of dendrites, and the length and density of basal and apical dendritic spines in the hippocampal CA1 region. The protein expression of filamin-A in the hippocampus of the mice was determined by Western blot. The protein expression and distribution of filamin-A in the hippocampal CA1 region were detected by immunofluorescence staining. RESULTS:Compared with normoxia exposure group, no significant difference of the number of dendritic branches in the hippocampal CA1 region after hypobaric hypoxia exposure was observed. However, the length of basal spines and apical spines was increased significantly (P<0.05), and the density of basal spines and apical spines was significantly reduced after hypobaric hypoxia exposure (P<0.01). The results of Western blot showed that the protein expression of filamin-A in the hippocampus of the mice after hypobaric hypoxia exposure was lower than that in normoxia exposure group (P<0.01 or P<0.05). Immunofluorescence staining showed that the filamin-A protein was expressed in the mouse hippocampal CA1 region, and the expression level after hypobaric hypoxia exposure was lower than that in normoxia group. CONCLUSION:Chronic hypobaric hypoxia exposure affects the protein expression level of filamin-A in the mouse hippocampal CA1 region, thus leading to the morphological changes of dendritic spines in the hippocampal CA1 region.     

Risk for interspecies transmission of zoonotic pathogens during poultry processing and pork production in Peru: A qualitative study

Interspecies transmission of pathogens is an unfrequent but naturally occurring event and human activities may favour opportunities not previously reported. Reassortment of zoonotic pathogens like influenza A virus can result from these activities. Recently, swine and birds have played a central role as “mixing vessels” for epidemic and pandemic events related to strains like H1N1 and H5N1. Unsafe practices in poultry markets and swine farms can lead to interspecies transmission, favouring the emergence of novel strains. Thus, understanding practices that lead to interspecies interactions is crucial. This qualitative study aimed to evaluate poultry processing practices in formal and informal markets and the use of leftovers by swine farmers in three Peruvian cities: Lima (capital), Tumbes (coastal) and Tarapoto (jungle). We conducted 80 direct observations at formal and informal markets and interviewed 15 swine farmers. Processors slaughter and pluck chickens and vendors and/or processors eviscerate chickens. Food safety and hygiene practices were suboptimal or absent, although some heterogeneity was observed between cities and chicken vendors versus processors. Both vendors (76%) and processors (100%) sold the chicken viscera leftovers to swine farmers, representing the main source of chicken viscera for swine farms (53%). Swine farmers fed the chicken viscera to their swine. Chicken viscera cooking times varied widely and were insufficient in some cases. Non‐abattoired poultry leads to the sale of poultry leftovers to small‐scale swine farms, resulting in indirect but frequent interspecies contacts that can lead to interspecies transmission of bacterial pathogens or the reassortment of influenza A viruses. These interactions are exacerbated by suboptimal safety and hygiene conditions. People involved in these activities constitute an at‐risk population who could play a central role in preventing the transmission of pathogens between species. Educational interventions on hygiene and food safety practices will be important for reducing the risk of interspecies influenza transmission.     

Ammonia dynamics in relation to hatching in Atlantic halibut (Hippoglossus hippoglossus L.)

Total ammonia content (T_Amm) and excretion (J_Amm), and ionic content (K⁺, Na⁺, Cl_-) have been studied in embryos and yolk-sac larvae of Atlantic halibut (Hippoglossus hippoglossus L.) maintained in darkness (6 °C and 34% S) or in light (light-arrested, nonon-hatching embryos). The T_Amm of the eggs increased from 250-300 nmol ind^-1 during the first 5-10 days post fertilization (dPF) to 400-500 nmol ind^-1 at the time of natural hatching in darkness. T_Amm did not start to decrease before 2-5 days after hatch, and yolk-sac larvae had a higher T_Amm compared to the light-arrested embryos of the same age and batch. J_Amm increased exponentially rom about 0.05 nmol ind^-1 h^-1 at 10 dPF to about 3 nmol ind^-1 h^-1 at hatch. Embryos undergoing hatching showed a significantly higher J_Amm than non-hatching, light-arrested embryos of the same age. The content of K+ in distilled water rinsed eggs declined from about 0.85 µmol ind^-1 at 2-4 dPF to about 0.15 µmol ind^-1 at hatch, while that of Cl^- remained constant at about t 0.85 µmol in^-1, and that of Na⁺ increased slowly from 0.10 to 0.20 µmol ind^-1 . Based on the measured ions, there was an anionic deficit in the egg, especially during the first week of development. When exposed to increased ambient total ammonia (0-27 mM NH4Cl), no mortality occurred, and no significant increase was found in the T_Amm of the Atlantic halibut egg before 9.2 dPF despite an estimated large inward diffusion gradient for the un-ionized ammonia species (NH₃). The delayed release of T_Amm comp ared to embryos and yolk-sac larvae of other marine teleosts, may relate to the deep-water spawning of the Atlantic halibut, and the buoyancy regulation of the yolk-sac larvae.     

氨氮胁迫对中国明对虾血淋巴氨氮、尿素氮含量和抗氧化能力的影响

将600尾体重为(5.0±1.2)g的健康中国明对虾(Fenneropenaeus chinensis)随机分为5组,每组6个重复,每个重复20尾虾,分别暴露于不同氨氮质量浓度(0 mg/L、2 mg/L、4 mg/L、6 mg/L和8 mg/L)海水中,于胁迫后6 h、24 h、48 h、72 h和96 h测定血淋巴氨氮、尿素氮含量、总抗氧化能力(T-AOC)、抗超氧阴离子活力和血淋巴细胞过氧化氢酶(CAT)基因、过氧化物还原酶(Prx)基因和含半胱氨酸的天冬氨酸蛋白水解酶(caspase)基因的相对表达量,以0 mg/L氨氮组作为对照。结果显示,随着氨氮胁迫时间的延长,中国明对虾血淋巴氨氮含量逐渐积累,以8 mg/L组对虾血淋巴氨氮含量最高,是对照组的5.85倍。氨氮胁迫6 h,胁迫组中国明对虾血淋巴尿素氮含量显著高于对照组(P0.05),其中6 mg/L组对虾血淋巴尿素氮含量最高,是对照组的2.22倍。氨氮胁迫下中国明对虾血淋巴T-AOC、Prx mRNA相对表达量随着取样时间推移先升高后降低,而血淋巴抗超氧阴离子活力、CAT和caspase mRNA相对表达量随时间增加呈现先上升后下降再上升的变化过程。氨氮胁迫下中国明对虾血淋巴抗氧化能力被显著诱导,这可能破坏机体的氧化-抗氧化系统的平衡,从而导致caspase mRNA相对表达量的上调。     

2-硝基-4'-羟基二苯胺(HC Orange No.1)在鲫鱼肝脏中的富集及其对肝脏抗氧化指标的影响

采用室内模拟方法研究了2-硝基-4'-羟基二苯胺(HCOrangeNo.1)在鲫鱼(Carassiusauratus)肝脏中的富集规律及不同暴露时间对鲫鱼肝脏抗氧化指标的影响。结果表明,10d左右鲫鱼肝脏对HCOrangeNo.1的富集达到最大值,肝脏过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、谷胱甘肽硫转移酶(GST)及还原型谷胱甘肽(GSH)对HCOrangeNo.1都非常敏感,其中GST活性和GSH含量总体上被诱导增加;SOD和CAT活性基本上都是先升高后受到抑制。上述抗氧化指标可考虑作为水生生态系统中HCOrangeNo.1污染的生物监测指标。     

Tolerance of Atlantic salmon (Salmo salar) to dietborne endosulfan assessed by haematology,biochemistry, histology and growth

The inclusion of plant‐based ingredients in commercial fish feeds may pose a challenge because of the presence of undesirable substances, such as the pesticide endosulfan. Waterborne endosulfan is highly toxic to fish, whereas dietborne exposure has varied toxicity in different species. To investigate the systemic effects of endosulfan exposure, quadruplicate groups of Atlantic salmon (Salmo salar) were fed either 0 (control), 0.005 mg kg^?1; the European Union's maximum limit, or 10 or 20 times this level (0.05 and 0.1 mg kg^?1 respectively) for 95 days. There were no significant differences (P > 0.05) in liver somatic index, spleen somatic index, condition factor or growth among treatments. There were no indications of liver damage in fish from any of the groups in the biomarkers measured: plasma aspartate aminotransferase, plasma alanine aminotransferase and histopathology. Similarly, there were no apparent treatment‐related effects on the haematological parameters Hct, Hb, mean corpuscular volume, mean corpuscular haemoglobin concentration and mean corpuscular haemoglobin, and blood sodium, potassium, calcium and chloride levels were not significantly (P > 0.05) different among groups. Lipid digestibility, but not energy, protein, or glycogen digestibility, was significantly (P < 0.05) reduced at the highest exposure concentration. However, no significant differences were observed in lipid production value or lipid efficiency ratio. In contrast to previous studies, clinical histological abnormalities were not observed in the intestine, liver or spleen of endosulfan‐treated fish.     

Dietary α‐Ketoglutarate supplementation alleviates harmful effects of high environmental ammonia on grass carp,Ctenopharyngodon idella

Current intensive fish farming usually causes high environmental ammonia (HEA) in ponds that is toxic to fish. α‐Ketoglutarate (α‐KG) can be rapidly transaminated to glutamic acid and further aminated to glutamine. Therefore, we hypothesized that dietary α‐KG supplementation would alleviate HEA toxicity to fish. To test the hypothesis, 270 healthy grass carp (Ctenopharyngodon idella) juveniles were randomly assigned to control, HEA (18.37 mg/L ammonia) and HEA + α‐KG (0.75% of α‐KG) groups. Ammonia and free amino acid content in plasma and brain, liver glutamic pyruvic transaminase and glutamic oxaloacetic transaminase activity, and urea and glycogen content were measured on the first, seventh and 42nd days. Our results showed short‐term HEA exposure (1 day) led to a significant ammonia accumulation in the brain and plasma and significantly decreased glutamic and aspartic acid content in the brain and increased glutamine content in the brain and plasma. The long‐term HEA exposure (42 days) caused significant reductions in glycine and arginine content in the brain tissue. In most cases, dietary α‐KG supplementation alleviated the fluctuations in FAA content in the brain and plasma. Our results suggested dietary α‐KG alleviated HEA toxicity to grass carp.