Antiprotozoal activity of chloroquinoline based chalcones

A new series of chloroquinoline based chalcones were synthesized and evaluated for in vitro antiamoebic and antimalarial activities. The results showed that out of fifteen compounds, four were found to be more active against the Entamoeba histolytica; while one compound was moderatively active compared to the standard drug metronidazole (IC₅₀ = 1.46 μM). In contrast, in vitro antimalarial activity against the chloroquine-sensitive (3D7) strain of P. falciparum indicated relatively low activity when compared to controls such as chloroquine and quinine (IC₅₀ = 0.0065 μM and 0.14 μM, respectively). The toxicological studies of these compounds on human breast cancer MCF-7 cell line showed that all the compounds were non-toxic at the concentration range of 1.56-50 μM.     

Antiprotozoal activity of diospyrin towards Leishmania donovani promastigotes in vitro

Diospyrin, a bis-naphthoquinone derivative, isolated from a plant, known for its antitumour properties against Ehrlich ascites carcinoma in Swiss A mice, exhibits antiprotozoal activity towards L. donovani promastigotes in culture.     

国产红曲制品中桔青霉素污染水平研究

目的了解中国红曲制品中桔青霉素的污染水平。方法用高效液相色谱方法对采自市场或厂家送检的114个红曲产品进行了研究。结果114份样品中,桔青霉素阳性者68份,阳性率59.65%,污染水平范围0.18～1739.23mgkg,平均污染水平211.61mgkg(中位数6.62mgkg)。红曲产品种类不同,桔青霉素污染水平各异,以红曲红色素粉中桔青霉素含量最高,27份样品中有25份(92.59%)检出桔青霉素,污染水平范围0.85～1739.93mgkg,平均508.40mgkg(中位数169.88mgkg)。其次为红曲米粉原料,19份样品中有12份(63.16%)桔青霉素阳性,但83.33%阳性样品中桔青霉素水平在10mgkg以下;功能性红曲中84%样品桔青霉素水平在6mgkg以下。结论国产红曲制品不同程度被桔青霉素污染,所调查样品中有15份(13.16%)色价桔青霉素比值超过日本标准。     

大米中桔青霉素的薄层色谱测定

建立了大米中桔青霉素的薄层色谱测定方法。大米样品用含 10 %乙醇酸的乙腈溶液提取 ,经过净化 ,再用三氯甲烷溶液定容至 1ml。薄层板浸泡在含草酸的甲醇溶液中进行预处理。大米样品中桔青霉素的加入水平为 10 0～ 10 0 0 μg kg时 ,回收率为 80 %～ 12 0 % ,方法的灵敏度为 30 μg kg ,最低检出量为 0 0 0 3μg     

Cytotoxicity of citrinin in cultured kidney epithelial cell systems

Cytotoxicity of citrinin, a fungal metabolite and a common food contaminant, was evaluated in an established cell line, Madin-Darby bovine kidney (MDBK) cells and primary fetal bovine kidney (PFBK) cells. Citrinin is a known nephrotoxicant but produced a low order of cytotoxicity in cultured renal cells. A dose-dependent cytotoxic effect was observed at millimolar concentrations of the toxin. MDBK cells were more sensitive than the PFBK cells. The primary effect of this chemical was on the adherence of MDBK cells to the culture dish. Microscopic evaluation of morphologic changes indicated that cells elongated, flattened, swelled, and became rounded. The appropriateness of toxicity evaluation in culture systems in vitro is considered.     

液相色谱-串联质谱法检测食品中的桔霉素

目的:建立食品中桔霉素的液相色谱-质谱测定方法。方法:样品经处理后,以水(含0.1%甲酸) 乙腈=40 60作流动相,在HypersilGold液相色谱柱(150×2.1 mm,3μm)上进行分离;用三级四极质谱检测器:电喷雾源(ESI),正离子方式,选择反应监测(SRM)对桔霉素的母离子和子离子进行监测并定性定量。结果:本方法桔霉素的标准在0.01~100μg/L范围内线性良好,Y=1042863X-588493,r=0.9998,方法的精密度(RSD)为2.8%,样品回收率95.6%~98.0%,以母离子(m/z 251),子离子(m/z 233和m/z 205)为定性定量离子,检测限为0.01μg/L,取样品5 g,处理定容体积10.0 ml,样品中桔霉素最小检测浓度达0.02μg/kg。结论:本方法简便快速、灵敏、定性定量准确,适合食品中桔霉素的测定。     

Biochemical alterations induced by citrinin in cultured kidney epithelial cell systems

Citrinin is a fungal metabolite and a common food contaminant. Cytotoxicity of this nephrotoxic mycotoxin in renal epithelial cells was recently reported. The primary effect of this chemical was on the adherence of cells to the culture dish. We have evaluated the effect of citrinin on macromolecular syntheses and selected cellular enzymes in Madin-Darby bovine kidney (MDBK) cells and primary fetal bovine kidney (PFBK) cultures. Citrinin inhibited the synthesis of macromolecules, especially DNA, perhaps due to inhibition of the transport of precursor compounds into the cells. Protein and RNA synthesis followed a parallel trend. Enzyme activities, namely K⁺-dependent phosphatase, alkaline phosphatase and succinic dehydrogenase, were subsequently reduced. The cellular enzyme activities were not directly influenced by the presence of citrinin. Results suggested that citrinin affects cellular metabolism leading to cytotoxicity in renal cells.Published as Utah State University Agricultural Experiment State Journal Paper Number 3338.     

抗桔青霉素单克隆抗体的研制与鉴定

目的制备抗桔青霉素的单克隆抗体。方法采用活性酯法、甲醛加成法和羰基二咪唑法制备了4种桔青霉素与载体蛋白的偶联物(A、B、C和D),免疫小鼠制备抗桔青霉素单克隆抗体。结果免疫原性鉴定证明偶联物C可刺激BALB/c小鼠产生抗桔青霉素的抗体,细胞融合后筛选到一株抗桔青霉素的单克隆抗体,单抗与赭曲霉毒素A、黄曲霉毒素B1和展青霉素等毒素交叉反应低于0.01%,在此基础上建立了竞争ELISA检测方法,线性范围为20~10,00ng/ml,检测下限为10ng/ml。在小麦样品中的加标回收率为95%~112%,变异系数为9.1%~18.6%。结论本研究成功筛选到抗桔青霉素单克隆抗体。     

食品工业用红曲菌株产桔青霉素能力的研究

为筛选出低产或不产桔青霉素的红曲霉菌株 ,选用 3 5株食品发酵工业用红曲霉 ,研究不同的培养条件对其产桔青霉素能力的影响。结果显示 ,所有菌株在大米培养基上均产桔青霉素 ,3 0个株菌 (85 71% )在液体培养基上产毒 ;两种培养基上的产毒范围分别为 0 2 8～ 2 458 80mg kg和 0 0 9～ 55 65mg kg ,毒素产量均数分别为 2 0 1 60mg kg和 11 99mg kg ,中位数分别为 61 99mg kg和 3 51mg kg ,同一菌株在大米培养基上产桔青霉素能力高于液体培养基。色价测定结果表明 ,菌株在大米培养基上的色素产量也高于液体培养基 (3～ 50 9倍 ,平均 93倍 )。本研究筛选出一株在大米培养基上色素产量最高 (113 4U g)而桔青霉素产量较低、适用于食品发酵工业用的红曲霉菌株。研究结果提示 ,用于生产食品或保健食品的红曲菌种在使用前必须进行安全性评价 ,并在全国范围内定期对生产厂家、菌种保藏单位使用和保藏的菌种进行产桔青霉素能力调查 ,对红曲发酵产品中桔青霉素污染水平进行监测 ,建立我国红曲制品中桔青霉素的限量标准迫在眉睫     

桔青霉素简介及其免疫学检测方法研究进展

桔青霉素是能引起肾脏毒性的真菌毒素 ,并有致癌性。本文综述了桔青霉素的物理、化学和生物学特性及其免疫学检测方法研究进展。     

In vitro effects of the nephrotoxins ochratoxin A and citrinin upon biochemical function of porcine kidney

Ochratoxin A and citrinin are nephrotoxic mycotoxins found in a variety of foods and feeds. Before studying possible interactions between these two toxins, their individual biochemical effects were examined in vitro by using renal cortical explants derived from male swine of the Hormel-Hanford strain. The following measurements were performed: macromolecule biosynthesis (protein, RNA, and DNA), respiration (¹⁴CO₂ from [¹⁴C]glucose), organic ion (tetraethyl ammonium acetate, i.e., TEA) transport, and membrane perturbation (protein leakage into medium). Levels of the toxins ranged from 0.001 to 1 mM. Ochratoxin A inhibited macromolecule biosynthesis at a lower concentration (0.001 mM) than did citrinin. Protein and DNA synthesis were particularly sensitive to ochratoxin A. Syntheses of protein and DNA were inhibited at ochratoxin A concentrations of 0.01 and 0.001 mM, respectively. RNA synthesis was less sensitive to the mycotoxin; it was inhibited only 60% at 1 mM, the highest concentration of ochratoxin A tested. Citrinin levels of 0.01 mM were required for inhibition of RNA, DNA, and protein synthesis. Inhibition by citrinin was approximately equal for all three classes of macromolecules. Citrinin was more effective than ochratoxin A in the inhibition of respiration and TEA transport; the minimum effective levels of citrinin were 1 and 0.01 mM, respectively. Serious membrane damage as evidenced by increased protein leakage was not caused by either toxin. Stimulation of respiration, perhaps reflective of uncoupling of oxidative phosphorylation, was produced by an ochratoxin A concentration of 1 mM. Inhibition of macromolecule biosynthesis does not seem to be related to the effect of either toxin upon respiration, although a causal relationship between the effects of ochratoxin A on respiration and TEA transport cannot be ruled out.     

Construction of a replacement vector to disrupt pksCT gene for the mycotoxin citrinin biosynthesis in Monascus aurantiacus and maintain food red pigment production

More and more people pay attention to citrinin produced by Monascus, which has nephrotoxic activity in mammals. It was reported that pksCT gene is responsible for citrinin biosynthesis in Monascus purpureus. In this paper, two DNA fragments in both ends of pksCT were amplified by genomic PCR from fourteen Monascus spp. strains. The PCR products were gained from all of the strains. It is suggested that pksCT gene was highly conserved in different citrinin-producing Monascus strains. A pksCT-replacement vector (pHD106) was constructed to disrupt pksCT with a hygromycin resistance gene as the selection marker, and was transformed into M. aurantiacus Li AS3.4384. Three transformants (M. aurantiacus PHDS18, PHDS26, PHDS31) were selected from transformant selective plates. The targeting fragment D was gained by genomic PCR from PHDS18 and PHDS26 except PHDS31. The expressing citrinin capacities of PHDS26 was decreased by about 98%, while PHDS18 was reserved the high capacity of producing citrinin, after 10 days of growth on YM medium. The results indicated that PHDS26 is a pksCT-disrupted strain. There are maybe other genes besides pksCT responsible for citrinin biosynthesis in M. aurantiacus. It is the effective way to solve the problem of citrinin in M. aurantiacus products by constructing replacement vectors to disrupt the genes responsible for citrinin biosynthesis to reduce the capacity of expressing citrinin.     

Physical activity in pregnancy

Pregnancy is an important window in which to communicate to women about diet and lifestyle and encourage behaviour change. There appears to be an interest among pregnant women regarding how much and what kind of physical activity is appropriate during pregnancy. There are physiological changes that occur in pregnancy, which mean that pregnant women should be cautious when physically active and women should check with their midwife or general practitioner about what activities are suitable. For most women, moderate physical activity can be undertaken throughout pregnancy without adverse effects and physical activity can be beneficial for both mother and baby.     

Structurally related mycotoxins ochratoxin A, ochratoxin B, and citrinin differ in their genotoxic activities and in their mode of action in human-derived liver (HepG2) cells: implications for risk assessment

To elucidate the effects of three structurally related mycotoxins, namely, ochratoxin A (OTA), ochratoxin B (OTB), and citrinin (CIT), on human health, we investigated their acute toxic, mitogenic, and genotoxic effects in the human-derived liver cell line (HepG2). These compounds are found in moldy foods in endemic areas of nephropathy, which is associated with urinary tract cancers. In agreement with previous experiments, we found that OTA causes a dose-dependent induction of micronuclei (MN) and DNA migration in the single-cell gel electrophoresis (SCGE) assay, which was statistically significant at concentrations of > or =5 microg/ml. In contrast, OTB was devoid of genotoxic activity under identical conditions, but the compound caused pronounced inhibition of cell division even at doses lower than OTA (10 microg/ml). CIT caused an effect similar to that of OTA in MN assays (significant at dose levels of > or =2.5 microg/ml) but was negative in the SCGE test. All compounds failed to induce mutations in Salmonella/microsome assays in strains TA 98 and TA 100 after addition of HepG2-derived enzyme homogenate (S9-mix). By use of DNA-centromeric probes we found that induction of MN by OTA involves chromosome breaking effects (55-60% of the MN were centromere negative), whereas CIT-induced MN were predominantly centromere positive (78-82%). Our findings indicate that OTB is devoid of genotoxic activity in human-derived cells and therefore probably not a genotoxic carcinogen in humans. In contrast, CIT was an equally potent inducer of MN in HepG2 cells as OTA, but this effect is caused by a different mechanism, namely, aneuploidy. Furthermore, our data suggest that combined exposure to structurally related mycotoxins that cause DNA damage via completely different mechanisms may significantly increase the cancer risk of humans consuming moldy foods.     

Antioxidant activity in human faeces

Scarcely-absorbed antioxidants might reach the large bowel and exhibit antioxidant activity, opposing the action of reactive O species by bacterial and cellular metabolism and thus contributing to protection from oxidative damage-induced gastrointestinal diseases. This study was carried out to evaluate the antioxidant activity in the faeces of a group of healthy subjects on a freely-selected diet, and to look for possible associations with the intake of some macro- and micronutrients and food groups. Fourteen subjects recorded their food intake three times for a period of 2 d, each time collecting all the faeces passed during the next 24 h. Total antioxidant activity (TAA; mmol 6-hydroxy-2,5,7,8 tetramethylchroman-2-carboxylic acid (Trolox)/kg) of faecal suspensions was measured using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS(.+)) decolorisation assay. The average TAA value of faeces was 26.6 (sd 10.2) mmol Trolox/kg wet faeces (range 7.5-50.5). The total amount of antioxidant equivalents excreted over 24 h, derived by multiplying the TAA by the amount of faeces passed over 24 h, was 3.24 (sd 1.51) mmol Trolox (range 0.92-5.82) and this was significantly correlated with the average 24 h intake of coffee red wine and particularly to the sum of coffee and red wine In conclusion, the faeces of healthy subjects show detectable capacity to scavenge radical cations, suggesting that antioxidant activity occurs in the colonic lumen. Moreover, such activity seems at least in part to be related to dietary habits.