Lack of mutagenicity of fasciolicides

Six fasciolicides, bithionol, bromofenofos, DS-6, nitroxynil, oxyclozanide and tribromsalan, were tested for mutagenicity in the Salmonella reverse mutation test using S. typhimurium tester strains TA100, TA98, TA1535, TA1537 and TA1538 and the micronucleus test in mice. None of the fasciolicides increased the number of revertant colonies in any tester strain in the presence and absence of S9 mix, nor did they induce a significant increase of the micronuclei in erythrocytes. Taking the high correlation between mutagenicity and carcinogenicity into consideration, these results suggest that the fasciolicides tested in this investigation are devoid of carcinogenic action.     

Lack of mutagenicity of fasciolicides

Six fasciolicides, bithionol, bromofenofos, DS-6, nitroxynil, oxyclozanide and tribromsalan, were tested for mutagenicity in theSalmonella reverse mutation test usingS.typhimurium tester strains TA100, TA98, TA153, TA1537 and TA1538 and the micronucleus test in mice. None of the fasciolicides increased the number of revertant colonies in any tester strain in the presence and absence of S9 mix, nor did they induce a significant increase of the micronuclei in erythrocytes. Taking the high correlation between mutagenicity and carcinogenicity into consideration, these results suggest that the fasciolicides tested in this investigation are devoid of carcinogenic action.     

Mutagenicity of airborne particulates in Sagamihara City.

Airborne particulates in Sagamihara city were collected on quartz fibre filters using a high-volume air sampler for 14 days in each month from July 1984 to June 1985. Organic components in airborne particulates were extracted by the ultrasonic extraction method using benzene-ethanol (3:1 v/v) as an extracting solvent. The mutagenecities of airborne particulates extract were measured by the pre-incubation method using Salmonella typhimurium strains TA100 and TA98 with and without S-9mix. The concentration of airborne particulates was nearly the same level throughout the survey period, but the content of extract in particulates of winter was higher than those of other seasons. All the airborne particulates extracts showed positive mutagenic response to both strains with and without S-9mix. The average of mutagenic activities (revertants/m3 air) in winter was significantly higher than those in summer and spring. Furthermore, mutagenic activities fluctuated sharply in one month from several to ten times compared with the normal level, depending upon sampling days, and tended to be lower on Sundays and holidays in summer and new year holidays. In many days mutagenic activities without S-9mix were comparatively higher than those with S-9mix. The existence of nitroarene was surveyed using TA98NR strain. Nitroarene was found to be higher concentration in summer than in winter.     

亚硒酸钠突变试验研究

为评价亚硒酸钠的致突变性,进行了Ames试验,结果表明：在5～0.008 mg亚硒酸钠/皿剂量范围内,在加S9混合物和不加S9混合物时,受试物对鼠伤寒沙门氏菌TA97、TA98、TA1535、TA100、TA102五株试验菌株,在加与不加S-9时试验结果均为阴性.     

橘皮素乙酰酯致突变性研究

橘皮素乙酰酯是搐皮素结构改造后获得的衍生物，是一种新型杀螨药物，通过Ames试验、小鼠骨髓细胞微核试验、精子畸形试验，考察了橘皮素乙酰酯的致突变性。结果：在活化与非活化条件下，诱发TA97、TA98、TAl00和TAl02的回变菌落数与自发回变菌落数相近，无剂量反应关系；各试验组微核率(2．20‰～2．40‰)与阴性(2．00‰)和溶剂对照组(1．88‰)相近；精子畸形率(2．48％～2．72％)与阴性(2．36％)和溶剂对照组(2．06％)比较也无显著差异。表明橘皮素乙酰酯无致突变性．     

紫锥菊提取物的Ames试验

通过对紫锥菊提取物进行昆明种小鼠伤寒沙门氏菌回复突变试验,评价该材料的潜在致突变性。用紫锥菊提取物制备混悬液进行Ames（致突变）试验,采用平板掺入法,计数TA97、TA98、TA100、TA102标准测试菌株在4个不同浓度下,于37℃培养48h后的回复突变菌落数。结果显示无论在＋S9和-S9的情况下,各剂量组均未引起测试菌株回变菌落数的明显增加,Ames试验结果为阴性。说明紫锥菊提取物不引起鼠伤寒沙门氏菌的回复突变数增加,无致基因突变性。     

A型、C型肉毒毒素对鼠伤寒沙门氏菌的诱变性研究

应用鼠伤寒沙门氏菌4种组氨酸缺陷型菌株TA97、TA98、TA100、TA102的诱变试验来研究A型、C型肉毒毒素的诱变作用。A型、C型肉毒毒素通过点试法、渗入法（-S9和＋S9）及液体预保温培养法检测，结果均为阴性，说明A型、C型肉毒毒素对原核细胞无诱变性。     

Mutagenicity,Creatine and Nutrient Contents of Pan Fried Meat from Various Animal Species

The mutagenic activity in extracts of fried meat from 16 different animal species was studied in Salmonella typhimurium TA98. In each experiment, 1 meat sample together with a standard beef sample was fried, and the mutagenicity was expressed relative to the beef sample. All meat samples showed less mutagenic activity than beef. The contents of creatine, creatinine, water, protein, carbohydrate and fat in the meat samples were analyzed, but mutagenicity was not correlated with the concentration of any of these constituents. Beef meat treated with creatinase to remove creatine produced reduced mutagenic activity. Possibly a threshold concentration of creatine is necessary to give a high mutagenic response.     

新型饲料添加剂喹烯酮磺酸盐特殊毒理学研究

采用Ames试验、微核试验、精子畸形试验等,考察新型饲料添加剂喹烯酮磺酸盐的特殊毒理学特征。Ames试验结果表明,喹烯酮磺酸盐对鼠伤寒沙门氏菌TA98和TA100两个标准菌株均产生诱变性,并且在加入S9代谢活化系统后回复突变菌落数明显减少;小鼠体内微核试验和精子畸形试验结果均为阴性。     

鸡传染性支气管炎病毒中国地方分离株S1基因5′端的变异

对自海南省、广西省发生鸡传染性支气管炎 (IB)鸡群分离的 4株 IBV分离株 (Ha N- 1/95、Ha N- 2 /95、GX- 1/98、GX- 2 /98)的主要免疫原纤突蛋白 S1基因经 RT- PCR扩增其 5′端约 1.2 kb的目的片段 ,将其插入载体 p MD 18- T中 ,在大肠杆菌中实现目的基因的克隆。对克隆的目的基因经限制性酶切分析及 PCR鉴定后 ,以双脱氧链终止法测定其核苷酸序列 ,并与 Gen Bank中的参考毒株 (H12 0、SD- 1/97和 Holte)相应序列作比较 ,分析其同源性。结果表明 ,Ha N- 1/95、Ha N- 2 /95、GX- 1/98及 SD- 1/97与疫苗株 H12 0的核苷酸序列同源性分别为 99.5 %、99.2 %、97.9%和99.5 % ,其推导氨基酸序列同源性分别为 99.1%、98.9%、96 .9%和 99.2 %。 GX- 2 /98与 Holte株的核苷酸序列同源率为 99.0 % ,其推导的氨基酸序列同源性为 98.6 % ,而与其他中国分离株的核苷酸序列的同源性仅为 70 %左右 ,氨基酸序列的同源性仅为 6 8%左右。     

鼠伤寒沙门氏菌致突变试验的方法学研究

本文对鼠伤寒沙门氏菌致突变试验在国内实验条件下方法标准化进行了研究。国产试剂配制的营养肉汤可满足试验菌株的营养需求,烧瓶振荡培养10小时即可达1～2×10~9存活菌/ml,肉汤培养物稀释后测定OD650可监测细菌密度。国产五氯联苯和Aroclor 1254诱导的Sprague-Dawley及Wistar大鼠肝S9活化苯并(a)芘及2-乙酰氨基芴的能力相似(P>0.05)。本文还提出以点试验估计受试物毒性及以参比物减小或消除多次实验间的误差。     

Detection of Campylobacter jejuni strains in the water lines of a commercial broiler house and their relationship to the strains that colonized the chickens

Campylobacter jejuni is frequently present in the intestinal tract of commercial broiler chickens, and their drinking water has been proposed to be an initial source of bacteria for newly hatched chicks. We studied three sequential commercial broiler flocks raised in a house from which we had cultured C. jejuni from the nipple waters prior to placement of the first flock. Campylobacter cells were detected by immunofluorescence in the biofilm of the drinking nipples during the weeks when the flock was colonized with C. jejuni but not during weeks when the birds were negative. Campylobacter jejuni was isolated from the drinking water during the growth of the first flock and was present in the birds from all three flocks. Randomly amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR) typing with primer OPA11 indicated that seven distinct strains were present within the broiler house. One strain found in drinking water was similar to a strain found in birds in the second flock; however, RAPD-PCR with primer HLW85 showed that the strains were not identical. These results suggest that although the watering system is a potential source of C. jejuni in broiler flocks, the waterborne strain in this study was not detected in the birds.     

Attenuation, safety, and efficacy of an infectious bronchitis virus GA98 serotype vaccine

In 1998, novel strains of infectious bronchitis virus (IBV) were identified in chickens from the southeastern United States and classified as a new serotype designated Georgia 98 (GA98). Because of the widespread nature of the GA98 virus in the southeastern United States and the lack of adequate protection with the DE072 vaccine, we developed a specific vaccine for the GA98 serotype. The GA98/0470/98 isolate of IBV was passaged in embryonating chicken eggs 70 times, and attenuation of the virus was determined in specific-pathogen-free chicks. Pass 70 of the GA98/0470/98 strain of IBV when given at 1 day of age by coarse spray and at 14 days of age in the drinking water at 1 x 10(4.5) 50% embryo infectious dose/bird protected against the homologous GA98 challenge as well as provided good protection against the DE072-type virus. In addition, the vaccine was shown to be adequately attenuated and safe at a 10x dosage.     

高钠所致肺动脉高压肉鸡肺细小动脉病理改变的图象分析

240羽健康AA肉鸡随机均分为试验1组，试验2组和对照组，从8日龄起分别饮用含Na^ 为0.06%、0.12%和0.0%的饮水，其它饲养管理条件相同，分别于12、19、30、34、39日龄抽取各组参试鸡，以右心室（Right ventricle,RV)与全心室（Total ventrcle,TV)的重量比（RV／TV）作为判定肺动脉高压的依据，用图象分析仪对肺细小动脉病理变化作定量检测。结果表明：34、39日龄时，试验1组和试验2组管壁面积／管总面积和中膜厚度占外径百分值明显大于对照组，肺小动脉密度明显低，其RV／TV值均大于0.25，表明试验组肉鸡发生了肺动脉高压。由此可见，由高钠引起肉鸡肺细小动脉血管重构的病变可能参与了肺动脉高压的形成过程。     

J亚群禽白血病病毒安徽分离株的鉴定及其gp85基因序列分析

从安徽省的黄羽肉鸡和罗曼蛋鸡中各分离鉴定出1株J亚群禽白血病病毒,克隆获得了2条相应的gp85基因序列,并与参考毒株进行序列比对。结果表明,两分离毒株与J亚群参考毒株同源性为82.1%~99.4%,分离毒株之间同源性为85.4%。其中肉鸡分离毒株与J亚群原型毒株HPRS-103同源性为97.1%,与J亚群国内毒株SD09TA04、SDYC02J同源性均为99.4%;蛋鸡分离毒株与HPRS-103的同源性为89.0%,与SD09TA04和SDYC02J同源性仅为88.6%。两分离毒株的gp85氨基酸序列出现突变和缺失,在高变区hr1、hr2变异明显。进化分析进一步表明,2个分离毒株亲缘关系较远,可能来源于不同的原始病毒株。     

高钼环境分布与家畜钼中毒研究

陕西省境内某钼矿的选矿废水常年排放到南洛河,污染了河水。家畜饮用污染废水或采食河边牧草后即发生以腹泻为主的钼中毒,发病率达18.74％,死亡率为9.41％,使该地区畜牧业损失严重。经对15个品种219份样品1800余样次毒源成分分析检测,结果表明,钼在水、土壤、植物和动物组织中的含量均属高浓度水平。家畜饮用含有高钼污水,摄入的钼量极易达到中毒标准而致病。冶金工业污染引起高水平钼在食物链上正相关分布与迁移即为中毒原因。单纯饮用高钼污水完全能够引起反刍动物中毒。     

Guinea pig (Cavia porcellus) drinking preferences: do nipple drinkers compensate for behaviourally deficient diets?

When offered diets with hay ad libitum, rabbits (Oryctolagus cuniculus) clearly prefer open dishes over nipple drinkers, but whether this preference also applies in guinea pigs (Cavia porcellus) is unsure. We tested the drinker preference of 10 guinea pigs when offered open dishes (OD) and nipple drinkers (ND) simultaneously and measured the amount of water consumed by each animal on four different diets (grass hay 100%, or as 10% of intake on diets of fresh parsley, seed mix or pelleted complete feed, respectively) on either of the drinking systems. All animals ingested the hay portion of the combined diets first. The amount of water consumed differed significantly between individual animals. Animals drank less water on parsley than on the other diets. Nine of 10 animals clearly preferred ND when having a choice, and eight of these drank more when on ND only. The difference between the drinking systems was not consistent across all diets: on hay, similar amounts of water were drunk when on OD or ND only. Differences in water intake were reflected in urine production. Because drinking from ND in guinea pigs involves jaw movements similar to those in chewing, the results could suggest that when motivation for oral processing behaviour is not satisfied by a diet, animals may respond in using ND beyond physiological water necessity. Whereas physiological water requirements are probably better investigated with other drinking systems due to a possible overestimation when using ND, offering ND to pet guinea pigs most likely offers a form of behavioural enrichment that at the same time may increase water intake and hence act as prophylaxis against urolithiasis.     

Effect of components of green tea extracts, caffeine and catechins on hepatic drug metabolizing enzyme activities and mutagenic transformation of carcinogens

Green tea contains catechins and caffeine as major constituents. Treatment of rats with green tea (2.5% w/v) significantly increased 7-ethoxycoumarin O-deethylase (7-ECOD), caffeine N-1 demethylase (CN1D) and UDP-glucuronyltransferase (UGT) activities. Treatment with caffeine similarly activated CYP1A2 and related monooxygenases as well as UGT, while treatment with catechins induced UGT activity but not 7-ECOD or CN1D activity. Numbers of benzo[a]pyrene (BP)-induced revertant colonies in an Ames test (mutation assay) with S. typhimurium TA98 as the test strain were markedly larger when BP was preincubated with the liver S-9 (9000 x g supernatant of liver homogenate) from green tea-treated rats than when preincubated with that from control rats. In a modified Ames assay system in which UGT was activated by the addition of UDP-glucuronic acid to the preincubation mixture, the numbers of revertant colonies in the assay using liver S-9 from green tea-treated rats decreased to a similar level to that in the assay using S-9 from controls. The acceleration of two enzymatic reactions may contribute to the rapid elimination of BP; the first step, the formation of a metabolic intermediate (which is mutagenic) by CYP1A2 and the second, the conjugation of active metabolic intermediates by UGT. We speculated that green tea can reduce the amount of time carcinogens reside in the body and the chance that body tissues will be exposed to active metabolites of carcinogens thorough rapid elimination due to the simultaneous induction of CYP1A2 and UGT activities.     

Giardia in shellfish-farming areas: detection in mussels, river water and waste waters

Giardia cyst contamination of mussels (Mytilus galloprovincialis), raw and treated waste waters and water from rivers that flow into four Galician estuaries (NW Spain), where bivalve molluscs are cultured for human consumption, was studied. The high prevalence of contamination in mussels (41.8%, n=184), raw waste water (90.9%, n=11), treated waste water (87.5%, n=16) and in samples of river water (85.7%, n=7), with cyst counts of 9.8-1800.0, 7.0-2541.0 and 1.0-29.3 cysts l(-1), respectively, illustrate the wide distribution of this enteropathogen in the environment and the potential risk to public health associated with the consumption of raw or undercooking bivalves and use of these estuaries for recreational purposes.     

Antimutagenic and anticarcinogenic effect of methanol extracts of Petasites japonicus Maxim leaves

The methanol extract from the leaves of Petasites japonicus Maxim (PJ) was studied for its (anti-)mutagenic effect with the SOS chromotest and reverse mutation assay. The (anti-)carcinogenic effects were evaluated by the cytotoxicity on human cancer line cells and by the function and the expression of gap junctions in rat liver epithelial cell. PJ extracts significantly decreased spontaneous β-galactosidase activity and β-galactosidase activity induced by a mutagen, ICR, in Salmonella (S.) typhimurium TA 1535/pSK 1002. All doses of the extract (0.08-100 mg/plate) decreased the reversion frequency induced by benzo (α)pyrene (BaP) in S. typhimurium TA 98. It decreased not only the spontaneous reversion frequency but also that induced by BaP in S. typhimurium TA 100. PJ extract showed greater cytotoxic effects on human stomach, colon and uterus cancer cells than on other cancer cell types and normal rat liver epithelial cells. Dye transfers though gap junctions were significantly increased by PJ extracts at concentrations greater than 200 µg/mL and the inhibition of dye transfer by 12-O-tetradecanoylphorobol-13-acetate (TPA) was obstructed in all concentrations of PJ. PJ significantly increased the numbers of gap junction protein connexin 43, and increased the protein expression decreased by TPA in a dose-dependent manner. Based on these findings, PJ is suggested to contain antimutagenic and anticarcionogenic compounds.