Analysis of phenolic compounds by high-performance liquid chromatography and liquid chromatography/mass spectrometry in potato plant flowers, leaves, stems, and tubers and in home-processed potatoes

Potato plants synthesize phenolic compounds as protection against bruising and injury from bacteria, fungi, viruses, and insects. Because antioxidative phenolic compounds are also reported to participate in enzymatic browning reactions and to exhibit health-promoting effects in humans, a need exists for accurate methods to measure their content in fresh and processed potatoes. To contribute to our knowledge about the levels of phenolic compounds in potatoes, we validated and used high-performance liquid chromatography and liquid chromatography/mass spectrometry to measure levels of chlorogenic acid, a chlorogenic isomer, and caffeic acid in flowers, leaves, stems, and tubers of the potato plant and in home-processed potatoes. The total phenolic acid content of flowers (626 mg/100 g fresh wt) was 21 and 59 times greater than that of leaves and stems, respectively. For all samples, chlorogenic acid and its isomer contributed 96-98% to the total. Total phenolic acid levels (in g/100 g fresh wt) of peels of five potato varieties grown in Korea ranged from 6.5 to 42.1 and of the flesh (pulp) from 0.5 to 16.5, with peel/pulp ratios ranging from 2.6 to 21.1. The total phenolic acid content for 25 American potatoes ranged from 1.0 to 172. The highest amounts were present in red and purple potatoes. Home processing of pulp with various forms of heat induced reductions in the phenolic content. The described methodology should facilitate future studies on the role of potato phenolic compounds in the plant and the diet.     

Wheat bran oil and its fractions inhibit human colon cancer cell growth and intestinal tumorigenesis in Apc(min/+) mice

This study was designed to investigate the cancer preventive activities of wheat bran (WB) oil. We studied the colon cancer preventive effects of WB oil and its subfractions in the Apc(min/+) mouse model, a recognized mouse model for human colorectal cancer, and used human colon cancer cell lines (HCT-116 and HT-29) to identify possible active fractions in WB oil. Our results showed that the oil fraction of WB was more active than the water fraction against the growth of human colon cancer cell lines and that 2% WB oil significantly inhibited the overall tumorigenesis by 35.7% (p < 0.0001) in the Apc(min/+) mouse model. The WB oil was further fractioned into nonpolar lipids and phytochemicals and the phytochemical fraction was fractionated into phytosterols and phytosterol ferulates, 5-alk(en)ylresorcinols, and unidentified constituents by normal phase silica gel column chromatography. Results on cell culture showed that the phytochemical fraction had a higher inhibitory effect on HCT-116 human colon cancer cells than that of WB oil, whereas the nonpolar lipid fraction had less growth inhibitory effectiveness. However, neither fractions showed a stronger inhibition than WB oil in the Apc(min/+) mouse model. The current results demonstrate, for the first time, the intestinal cancer preventive activity of WB oil. The active ingredients, however, remain to be identified.     

Isolation and antifungal and antioomycete activities of staurosporine from Streptomyces roseoflavus strain LS-A24

The actinomycete strain LS-A24 active against some plant fungal and oomycete pathogens was isolated from a soil sample of the Sunghwan Lake in Korea. The cell wall composition and spore shape of strain LS-A24 were LL-diaminopimelic acid and spiral type, respectively. On the basis of the physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, strain LS-A24 was identical to Streptomyces roseoflavus. An antifungal and antioomycete antibiotic was isolated from LS-A24 using various chromatographic procedures. The molecular formular of the antibiotic was determined to be C(28)H(26)N(4)O(3), and on the basis of the NMR data, the antibiotic was confirmed to be staurosporine, 2,3,10,11,12,13-hexahydro-10R-methoxy-9S-methyl-11R-methylamino-9S,13R-epoxy-1H,9H-diindolo[1,2,3-gh:3',2',1'-lm]pyrrolo[3,4-j][1,7]benzodiazonin-1-one. Staurosporine completely inhibited the mycelial growth of Colletotrichum orbiculare, Phytophthora capsici, Rhizoctonia solani, Botrytis cinerea, and Cladosporium cucumerinum with minimum inhibitory concentration (MIC) values of 1-50 microg/mL for MICs. Staurosporine also was active against Saccharomyces cerevisiae, Bacillus subtilis ssp. subtilis, and Xanthomonas vesicatoria. Staurosporine and the commercial fungicide metalaxyl inhibited the development of Phytophthora blight on pepper plants. However, the control efficacy of staurosporine against the Phytophthora disease was somewhat less than that of metalaxyl. This is the first study to isolate staurosporine from S. roseoflavus and demonstrate its in vitro and in vivo antioomycete activity against P. capsici.     

The heartbeat of the Oligocene climate system

A 13-million-year continuous record of Oligocene climate from the equatorial Pacific reveals a pronounced "heartbeat" in the global carbon cycle and periodicity of glaciations. This heartbeat consists of 405,000-, 127,000-, and 96,000-year eccentricity cycles and 1.2-million-year obliquity cycles in periodically recurring glacial and carbon cycle events. That climate system response to intricate orbital variations suggests a fundamental interaction of the carbon cycle, solar forcing, and glacial events. Box modeling shows that the interaction of the carbon cycle and solar forcing modulates deep ocean acidity as well as the production and burial of global biomass. The pronounced 405,000-year eccentricity cycle is amplified by the long residence time of carbon in the oceans.     

Metagenomic analysis of the human distal gut microbiome

The human intestinal microbiota is composed of 10(13) to 10(14) microorganisms whose collective genome ("microbiome") contains at least 100 times as many genes as our own genome. We analyzed approximately 78 million base pairs of unique DNA sequence and 2062 polymerase chain reaction-amplified 16S ribosomal DNA sequences obtained from the fecal DNAs of two healthy adults. Using metabolic function analyses of identified genes, we compared our human genome with the average content of previously sequenced microbial genomes. Our microbiome has significantly enriched metabolism of glycans, amino acids, and xenobiotics; methanogenesis; and 2-methyl-d-erythritol 4-phosphate pathway-mediated biosynthesis of vitamins and isoprenoids. Thus, humans are superorganisms whose metabolism represents an amalgamation of microbial and human attributes.     

羊进行性肺炎诊断的微量免疫扩散试验

本文论述检查和测定羊进行性肺炎抗体的二种微量免疫扩散试验(MIDT)、用含有各种盐的浓度和不同 pH 值的底物来测定本试验的最适条件。应用淘汰母羊血清,将两种微量免疫扩散试验和一种宏量免疫扩散试验进行比较。微量免疫扩散试验比宏量免疫扩散试验所需试剂少且反应敏感。延长试验物感作时间后,三种试验结果相近。     

红树内生菌代谢产物抑菌作用的初步观察

观察红树内生菌CⅢ-1代谢产物对金黄色葡萄球菌、表面葡萄球菌、大肠杆菌以及沙门氏菌等常见动物病原菌的抑菌效果。结果表明,CⅢ-1代谢产物对金黄色葡萄球菌、埃希氏大肠杆菌有较强的抑制作用,且抑菌活性随代谢产物浓度的增加而增加;金黄色葡萄球菌、表面葡萄球菌和埃希氏大肠杆菌对8倍浓缩的CⅢ-1代谢产物高度敏感,但沙门氏菌呈中度敏感。CⅢ-1浓缩样品与几种常用抗生素的抑菌效果相当。     

山羊α-干扰素基因克隆、原核表达及其抗病毒活性研究

为研究雷州山羊α-干扰素基因的遗传变异及重组α-干扰素的抗病毒活性，采用RT-PCR扩增雷州山羊α-干扰素基因，分析其核苷酸序列；采用PCR方法扩增山羊α-干扰素基因成熟肽编码序列，构建原核表达载体pET- mIFN-α，并在大肠杆菌BL21（DE3）诱导表达；采用SDS-PAGE和Western-blot检测重组蛋白rG-mIFN-α；通过细胞病变抑制法测定其抗小反刍兽疫病毒（PPRV）和山羊痘病毒（GPV）活性。结果表明，雷州山羊α-干扰素全基因由570个核苷酸组成，编码189个氨基酸；与GenBank 上发表的山羊、林麝、弯角大羚羊、黄牛、瘤牛、绵羊、猪、人和鼠的核苷酸序列同源性分别为99.8%、95.6%、96.8%、94.7%、94.7%、96.8%、81.6%、77.8%和70.0%；氨基酸序列同源性分别为100%、92.6%、94.7%、92.1%、93.2%、93.7%、67.9% 、61.6%和55.3%，提示反刍动物α-干扰素基因的核苷酸和氨基酸序列高度保守；rG-IFNα主要以包涵体形式存在，分子质量约32 ku；重组山羊α-干扰素能显著抑制PPRV和GPV感染引起的细胞病变，其抗PPRV和GPV效价分别为1.6×10⁴ U/mg和1.35×10⁴ U/mg。