Functional identification of organic cation transporter 1 as an atenolol transporter sensitive to flavonoids

Atenolol, a β1-adrenergic receptor blocker, is administered orally and its intestinal absorption has recently been indicated to be mediated by carrier protein and reduced markedly by ingestion of some fruit juices, such as apple and orange juices. This could be postulated to be a problem arising from the interaction of some components of fruit juices with atenolol at a transporter involved in its intestinal uptake, but the responsible transporter and its interacting components have not been identified yet. In an attempt to examine that possibility, we could successfully find that human organic cation transporter 1 (OCT1/SLC22A1), which is suggested to be expressed at the brush border membrane of enterocytes, is highly capable of transporting atenolol. In this attempt, OCT1 was stably expressed in Madin-Darby canine kidney II cells and the specific uptake of atenolol by the transporter was found to be saturable, conforming to the Michaelis-Menten kinetics with the maximum transport rate (V_max) of 4.00 nmol/min/mg protein and the Michaelis constant (K_m) of 3.08 mM. Furthermore, the OCT1-specific uptake was found to be inhibited by various flavonoids, including those contained in fruit juices that have been suggested to interfere with intestinal atenolol absorption. Particularly, phloretin and quercetin, which are major components of apple juice, were potent in inhibiting OCT1-mediated atenolol transport with the inhibition constants of 38.0 and 48.0 µM, respectively. It is also notable that the inhibition by these flavonoids was of the noncompetitive type. These results indicate that OCT1 is an atenolol transporter that may be involved in intestinal atenolol uptake and sensitive to fruit juices, although its physiological and clinical relevance remains to be further examined.     

Lycopene,tomatoes, and coronary heart disease

Tomato and its major antioxidant component lycopene have recently been focused as important antioxidant nutrients because of their ability to reduce reactive oxygen species and to provide health benefits. Most of the studies were undertaken to determine the usefulness of lycopene against cancer and cardiovascular diseases. Epidemiological studies, however, yielded conflicting results. This study was undertaken to compare cardioprotective abilities of tomato juice and lycopene. Rats were gavaged either tomato juice or lycopene for 3 weeks. At the end of 3 weeks, isolated hearts were subjected to 30?min ischemia followed by 2?h of reperfusion. Both tomato juice and lycopene reduced the extent of lipid peroxidation; but only tomato juice, but not lycopene, improved post-ischemic ventricular function, and reduced myocardial infarct size and cardiomyocyte apoptosis. The results indicated for the first time that tomato juice, but not lycopene, possesses cardioprotective ability.     

Characterization of Endo β-1,3-Glucanase IV from Flavobacterium dormitator var. glucanolyticae FA-5

Endo β-1,3-glucanase IV (E.C. 3.2.1.6, endo-1,3(4)-β-d-glucanase) from Flav. dormitator var. glucanolyticae FA-5 was shown to be a glycoprotein by gel filtration and sodium dodecyl sulfate gel electrophoresis. The carbohydrate moiety was composed of 17 hexose units. The enzyme had an apparent molecular weight of 3.3 x 10⁴, determined by gel filtration, sodium dodecyl sulfate gel electrophoresis and ultracentrifugation. The enzyme showed maximum reactivity at pH 6.0 and 6.5 for living yeast cells and laminaran, respectively. The enzyme predominantly released laminaripen-taose from a variety of linear β-1,3-glucans and showed transglucanosylation activity. The amino acid composition of the enzyme and some of its physicochemical and enzymatic properties are described.     

The sequence of the isoepoxydon dehydrogenase gene of the patulin biosynthetic pathway in <Emphasis Type="Italic">Penicillium</Emphasis> species

Interest in species of the genus Penicillium is related to their ability to produce the mycotoxin patulin and to cause spoilage of fruit products worldwide. The sequence of the isoepoxydon dehydrogenase (idh) gene, a gene in the patulin biosynthetic pathway, was determined for 28 strains representing 12 different Penicillium species known to produce the mycotoxin patulin. Isolates of Penicillium carneum, Penicillium clavigerum, Penicillium concentricum, Penicillium coprobium, Penicillium dipodomyicola, Penicillium expansum, Penicillium gladioli, Penicillium glandicola, Penicillium griseofulvum, Penicillium paneum, Penicillium sclerotigenum and Penicillium vulpinum were compared. Primer pairs for DNA amplification and sequencing were designed from the P. griseofulvum idh gene (GenBank AF006680). The two introns present were removed from the nucleotide sequences, which were translated to produce the IDH sequences of the 12 species for comparison. Phylogenetic relationships among the species were determined from rDNA (ITS1, 5.8 S, ITS2 and partial sequence of 28S rDNA) and from the idh nucleotide sequences minus the two introns. Maximum parsimony analysis showed trees based on rDNA and idh sequences to be congruent. It is anticipated that the genetic information obtained in the present study will aid in the design of probes, specific for patulin biosynthetic pathway genes, to identify the presence of these mycotoxigenic fungi. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

粗毛栓菌诱变菌株SAH-12漆酶的分离纯化及酶学性质研究

粗毛栓菌Trametes gallica诱变菌株SAH-12是通过紫外诱变选育所得的漆酶高产菌株,Active-PAGE分析表明SAH-12在高氮低碳无机盐培养液（LM3）中至少分泌3种漆酶同工酶（Lac1、Lac2、Lac3）。采用硫酸铵盐析、透析和Sephadex-G75分子筛层析从其培养液中分离纯化得到电泳纯的Lac1,纯化倍数6.54,酶活性回收59.7%。Lac1经SDS-PAGE验证为一条带,其表观分子量为61.5kDa。Lac1为一种糖蛋白,含糖量11.6%,等电点pI 4.40,催化氧化底物ABTS的最适反应温度为60℃,最适pH为2.6,Km值为25μmol/L。Lac1在40℃（pH4.0）以下和pH1.5～5.0（28℃）范围内稳定。金属离子Fe²⁺、Ag⁺、Hg²⁺和Cr³⁺与抑制剂DTT、SDS、EDTA和DMSO对Lac1有抑制作用,其中Fe²⁺和DTT完全抑制酶活,而Cu²⁺对酶有明显激活作用,Mn²⁺、Zn²⁺对酶活影响不大。Lac1不仅可使一些合成染料明显脱色,而且对苹果汁多酚祛除也有较好效果。40℃用该酶（1U/mL）处理苹果汁5h,其多酚含量可降低40%。     

Apple juice and red wine induced mirror-image circular dichroism in quantum dots

Juices, wines, and extracts from plants contain high concentrations of various chiral compounds such as carboxylic acids or sugars. Several prior studies reported the synthesis of metallic and semiconducting nanoparticles relying on components of complex biological solutions. Herein, we present preparation of chiral CdS and CdSe quantum dots (QDs) using apple juice and red wine via phase transfer ligand exchange. Although both apple juice and red wine contain a complex mixture of chiral and achiral compounds, we have successfully used them for selective induction of predicted chiroptical properties and confirmed L-malic acid from the apple juice and L-tartaric acid from the red wine as the chiral inducers. This work illustrates the capability of using complex mixtures to construct chiral QDs with desired chiroptical properties as well as potential of QDs to selectively report a chiral molecule in a complex chiral mixture without the need for elaborate chiral recognition system.     

Efficiency of high pressure treatment for destruction of Listeria monocytogenes in fruit juices

The objective of this study was to compare high pressure resistance of Listeria monocytogenes strains at 25 degrees C and 50 degrees C at 350 MPa and to use high pressure (250 MPa and 350 MPa) at 30 degrees C and 40 degrees C for the inactivation of the relatively most pressure resistant strain inoculated in pasteurized apple, apricot, cherry and orange juices. L. monocytogenes CA was found to be the relatively most pressure resistant strain and increasing pressurization from 250 MPa to 350 MPa at 30 degrees C had an additional three to four log cycle reduction in viability, still leaving viable cells after 5 min. When 350 MPa at 40 degrees C for 5 min was applied more than eight log cycle reduction in cell population of all fruit juices was achieved. This study demonstrated that low temperature (40 degrees C) high pressure (350 MPa) treatment has the potential to inactivate relatively pressure resistant L. monocytogenes strains inoculated in different fruit juices within 5 min.     

Trypanosoma cruzi infection by oral route: how the interplay between parasite and host components modulates infectivity

Trypanosoma cruzi infection by oral route constitutes the most important mode of transmission in some geographical regions, as illustrated by reports on microepidemics and outbreaks of acute Chagas' disease acquired by ingestion of food contaminated with parasites from triatomine insects. In the mouse model, T. cruzi metacyclic trypomastigotes invade the gastric mucosal epithelium, a unique portal of entry for systemic infection. High efficiency of metacyclic forms in establishing infection by oral route is associated with expression of gp82, a stage-specific surface molecule that binds to gastric mucin and to epithelial cells. Gp82 promotes parasite entry by triggering the signaling cascades leading to intracellular Ca²⁺ mobilization. T. cruzi strains deficient in gp82 can effectively invade cells in vitro, by engaging the Ca²⁺ signal-inducing surface glycoprotein gp30. However, they are poorly infective in mice by oral route because gp30 has low affinity for gastric mucin. Metacyclic forms also express gp90, a stage-specific surface glycoprotein that binds to host cells and acts as a negative regulator of invasion. T. cruzi strains expressing gp90 at high levels, in addition to gp82 and gp30, are all poor cell invaders in vitro. Notwithstanding, their infectivity by oral route may vary because, unlike gp82 and gp30, which resist degradation by pepsin in the gastric milieu, the gp90 isoforms of different strains have varying susceptibility to peptic digestion. For instance, in a T. cruzi isolate, derived from an acute case of Chagas' disease acquired by oral route, gp90 is extensively degraded by gastric juice in the mouse stomach and this renders the parasite highly invasive towards target cells. If such an exacerbation of infectivity occurs in humans, it may be responsible for the severity of the disease reported in outbreaks of oral infection.