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Extract Concentration (extract + concentration)
Selected AbstractsAllelopathic Effects of Parthenium hysterophorus Extracts on Seed Germination and Seedling Growth of Eragrostis tefJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2002T. Tefera The present study was conducted to investigate the allelopathic effects of Parthenium hysterophorus weed on seed germination and seedling growth of tef. Flower, stem, root and leaf aqueous extracts of Parthenium at 0, 1, 5, and 10 % concentrations were applied to determine their effect on tef seed germination and seedling growth under laboratory conditions. Increasing concentrations of aqueous extracts of Parthenium from leaf and flower inhibited seed germination and complete failure of seed germination was recorded when the extract concentration from the leaf part was 10 %. In contrast, aqueous extracts from stem and root had no effect on tef seed germination. Roots appeared more sensitive to allelopathic effect than shoots. Extracts from flower, root and stem had a stimulatory effect on shoot length at all concentration levels, as against an inhibitory effect of leaf extracts. Root extracts at low concentration (1 %) greatly promoted root length but aqueous extracts from leaf and flower inhibited root length. [source] Batch production of L(+) lactic acid from whey by Lactobacillus casei (NRRL B-441)JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2004Ali O Büyükkileci Abstract The effects of temperature, pH, and medium composition on lactic acid production by Lactobacillus casei were investigated. The highest lactic acid productivity values were obtained at 37 °C and pH 5.5. The productivity was 1.87 g dm,3 h,1 at 37 °C in shake flasks. In the fermenter, a productivity of 3.97 g dm,3 h,1 was obtained at pH 5.5. The most appropriate yeast extract concentration was 5.0 g dm,3. Whey yielded a higher productivity value than the analytical lactose and glucose. Initial whey lactose concentration did not affect lactic acid productivity. MnSO4 ·H2O was necessary for lactic acid production by L casei from whey. Product yields were approximately 0.93 g lactic acid g lactose,1. Copyright © 2004 Society of Chemical Industry [source] Production of ,-galactosidase from recombinant Saccharomyces cerevisiae grown on lactoseJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2004Lucília Domingues Abstract Improved productivity and costs reduction in fermentation processes may be attained by using flocculating cell cultures. The production of extracellular heterologous ,-galactosidase by recombinant flocculating Saccharomyces cerevisiae cells, expressing the lacA gene (coding for ,-galactosidase) of Aspergillus niger under the ADHI promotor and terminator in a bioreactor was studied. The effects of lactose concentration and yeast extract concentration on ,-galactosidase production in a semi-synthetic medium were analysed. The extracellular ,-galactosidase activity increased linearly with increasing initial lactose concentrations (5,150 g dm,3). ,-Galactosidase production also increased with increased yeast extract concentration. During the entire fermentation, no accumulation of the hydrolysed sugars, glucose and galactose, was observed. The catabolic repression of the recombinant strain when cultured in a medium containing equal amounts of glucose and galactose was confirmed. In complete anaerobiosis, the fermentation of lactose resulted in a very slow fermentation pattern with lower levels of ,-galactosidase activity. The bioreactor operation together with optimisation of culture conditions (lactose and yeast extract concentration) led to a 21-fold increase in the extracellular ,-galactosidase activity produced when compared with preliminary Erlenmeyer fermentations. Copyright © 2004 Society of Chemical Industry [source] Mutagenicity and Safety Evaluation of Water Extract of,Coriander sativum,LeavesJOURNAL OF FOOD SCIENCE, Issue 1 2010Mariana Ramírez Reyes ABSTRACT:, Coriander has been used as a spice and medicinal plant for centuries. Several studies have described its biological properties and some reports have indicated its pharmacological actions in some human pathology. However, data on its toxicity and metabolism are limited or null, and no research has been conducted with mammalian cells. The purpose of this study was to evaluate the mutagenicity and safety of,Coriandrum sativum,extract. The mutagenic effects of,C. sativum,extract were evaluated by Ames test. Mutagenicity was present when the,C. sativum,extract was used in high concentrations in both tested strains (Salmonella typhimurium,TA97 and TA102). Our research showed that,C. sativum,extract reduced the cell survival of human cell lines (WRL-68 and 293Q cells) by inducing apoptosis and necrosis in the cases where extract concentration was the highest. The,C. sativum,extract altered the cell cycle; it increased the G1 phase of hepatic cells and reduced the G2+M phase in both cell lines in a dose-response manner. These results showed correlation with a reduction in the mitotic index. The extract also induced severe malformations during embryonic development. Exposure of chicken embryos to the,C. sativum,extract resulted in a dose-dependent increase of anomalies. Present results show that,C. sativum,extract reduced the axial skeleton and affected the neural tube, the somites, the cardiovascular structures, and the eye. According to the present results, the,C. sativum,aqueous extract cannot be considered safe. These results indicate that some significant adverse effects of,C. sativum,extract could be observed,in vivo. [source] Anti-sickling potential of Aloe vera extractJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2008Agunna Everest Ejele Abstract The effect of Aloe vera extract on the gelling time of human HbSS erythrocytes was investigated. The results showed that A. vera extract increased the gelling time of HbSS blood and inhibited sickling in vitro. In addition, a linear relationship was found between extract concentration and gelling time, suggesting that A. vera extract may have great potential in the management of sickle cell disease. Copyright © 2008 Society of Chemical Industry [source] Inhibition of 304 stainless steel corrosion in acidic solution by Ferula gumosa (galbanum) extractMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 11 2009M. Behpour Abstract The inhibition effect of the extract of galbanum (Ferula gummosa Boiss.) on the corrosion of 304 stainless steel in 2 M HCl solution was studied by weight loss measurements, Tafel polarization, and electrochemical impedance spectroscopy (EIS) methods. It was found that the inhibition efficiency (IE) increases as the extract concentration is increased. Tafel polarization method revealed the mixed mode inhibition of galbanum extract (GE) with predominant control of anodic reaction. The effect of temperature on the corrosion behavior of steel indicates that inhibition efficiency of the natural substance increases with the rise in temperature. At all temperatures, the adsorption of the extract components onto the steel surface was found to follow the Temkin adsorption isotherm. [source] Effects of sediment eluates and extracts from differently polluted small rivers on zebrafish embryos and larvaeJOURNAL OF FISH BIOLOGY, Issue 1 2002M. Strmac The effects on newly fertilized eggs, embryos and larvae of zebrafish Danio rerio following exposure to sediment samples from the more heavily contaminated River Körsch, southern Germany, occurred earlier and were more prominent than in samples from the less contaminated Krähenbach. Dose- and time-related effects following exposure to Körsch sediment eluates and extracts included: (1) hatching failure and subsequent death of larvae exposed to undiluted aqueous sediment eluates and reduced hatching rates at sediment extract concentrations 0·0125%; (2) increased mortality after exposure to 25 and 50% dilutions of aqueous sediment eluates, and dilutions of 0·00625% sediment extracts; (3) reduction of heart beat frequency for 50% dilutions of sediment eluates and concentrations of 0·025% extracts; (4) increased frequency of heart and yolk sac oedema after exposure to 0·0125% sediment extracts. Since adverse effects of sediment extracts observed in zebrafish laboratory tests correlated with reproductive failure in natural populations of brown trout Salmo trutta f. fario in the severely polluted River Körsch, early life stages tests with zebrafish appear to be a suitable tool to assess the contamination rate of natural sediments. [source] AQUEOUS GARLIC EXTRACT AND MICROBIOLOGICAL QUALITY OF REFRIGERATED POULTRY MEATJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2005KEILY ALVES DE MOURA OLIVEIRA ABSTRACT The antibacterial effect of garlic extract (5, 10 and 15%) was investigated on poultry carcasses obtained from a slaughterhouse, stored under refrigeration, and evaluated at selected time intervals. The effect of the garlic extract on the microbial contaminants of the poultry carcass surface , Salmonella, strict and facultative aerobic, mesophilic, and total and fecal coliforms , was evaluated. The garlic extract exhibited a concentration-dependent reduction of microbial contamination. Garlic extract concentrations of 10 and 15% were the most effective. The bacteriostatic action of garlic extract against mesophilic microbiota can be observed until the third storage day. The count of total and fecal coliforms remained low during the storage period. Chicken feed was the apparent source of Salmonella contamination, and the aqueous garlic extract was not effective against Salmonella. [source] EFFECTS OF BARLEY STRAW EXTRACT ON GROWTH OF FIVE SPECIES OF PLANKTONIC ALGAEJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Holz, J. C.1, Fessler, C. J.2, Severn, A. A.1 & Hoagland, K. D.1 1School of Natural Resource Sciences, University of Nebraska, 103 Plant Industry Bldg., Lincoln, NE, 68583-0814; 2Biology Department, Nebraska Wesleyan University, 5000 St. Paul Ave., Lincoln, NE, 68504; Phone: 402-472-6648; Fax: 402-472-2964 The effects of exposure to barley straw extract and the timing of exposure on the growth of four common cyanophyte species and one species of green algae were investigated in two laboratory experiments. Clonal cultures of Anabaena cylindrica, Cylindrospermum sp., Gloeocapsa sp., Eucapsis sp., and Chlorella vulgaris were obtained from culture collections. In both experiments, the algae were cultured in Guillard's WC medium at 20 °C on a 12:12 L/D photoperiod. In the first experiment, the algae were dosed with four concentrations of barley straw extract at the beginning of the experiment (day 0) and growth was monitored every second day using fluorometric detection of chlorophyll a for 14 d. In the second experiment, the algae were dosed with the same extract concentrations, but the extract was not added until the algae were in exponential growth phase (day 6). Both experiments also had control treatments (i.e. no extract) and each extract and control treatment was replicated five times. Growth of C. vulgaris was inhibited by all doses in both experiments, but inhibition was 22% greater when the extract was added on day 0. Growth Gleocapsa sp. was slightly inhibited by all doses when the extract was added on day 0, but not when it was added on day 6. No other species were inhibited, regardless of dose or timing of dose. The results of this study and other bioassay studies suggest that differential susceptibility to barley straw among algae is common and may reduce the effectiveness of barley straw as an algal control technique. [source] Antibacterial activities and total phenolic contents of grape pomace extractsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2004Gülcan Özkan Abstract The aim of this study was to determine the total phenolic contents and antibacterial effects of grape pomace extracts (cultivars Emir and Kalecik karasi) against 14 bacteria, and the effects of the extracts on the growth and survival of two of the bacteria during storage. The total phenolic contents of grape pomace of Emir and Kalecik karasi cultivars extracted with acetone/water/acetic acid (90:9.5:0.5) were 68.77 and 96.25 mg GAE g,1, respectively. The agar well diffusion method was used to test the antibacterial activity of the extracts at 1, 2.5, 5, 10 and 20% (w/v) concentrations in methanol on spoilage and pathogenic bacteria including Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, Escherichia coli O157:H7. Mycobacterium smegmatis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica. All the bacteria tested were inhibited by extract concentrations of 2.5, 5, 10 and 20%, except for Y enterocolitica which was not inhibited by the 2.5% concentration. However, pomace extracts at 1% concentration had no antibacterial activity against some of the bacteria. According to the agar well diffusion method, E coli O157:H7 was the most sensitive of the bacteria. Generally, using the serial dilution method, while the extracts at 0.5% concentration had bacteriostatic activities on E coli O157:H7 and S aureus, the extracts appeared to have bactericidal effects at 1 and 2.5% concentrations. In accordance with this method, S aureus was more sensitive than E coli O157:H7 to the extracts. Copyright © 2004 Society of Chemical Industry [source] Effect of X-Radiation on Lipid Peroxidation and Antioxidant Systems in Rats Treated with Saponin-containing CompoundsPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2008Omer Yalinkilic The aim of this study was to investigate the effect of three saponin-containing plant species extracts (Aesculuc hippocastanum L. seed extract [AHE], Medicago sativa L. extract [MSE] and Spinacia oleracea L. extract [SOE]) on lipid peroxidation and on antioxidant systems in rats exposed to X-rays (XR). The rats were divided into three categories. The first category served as controls and received only a standard diet. The second category served as the radiation group and received 5 and 10 Gy XR dose. The third category (XR+extract-treated) received plant extracts (25.0 or 50.0 mg kg,1 live weight) and 5 or 10 Gy XR dose. Blood samples were analyzed for their content of malondialdehyde (MDA), reduced glutathione (GSH), plasma vitamin C, ,-carotene and retinol. In animals receiving XR, the plasma MDA (P < 0.001) value significantly increased but the level of GSH (P < 0.01), vitamin C (P < 0.001), retinol and ,-carotene (P < 0.001) decreased significantly with increasing XR doses. In the XR+extract-treated groups, the concentrations of MDA increased significantly with increasing radiation but their concentrations decreased significantly with increasing extract concentrations. Plasma concentrations of GSH, ,-carotene, retinol and vitamin C in XR+extract-treated groups decreased significantly with increasing XR dose but their concentrations increased with increasing extract doses. Further, comparison of blood samples of XR+extract-treated groups with those from the control group showed that GSH, ,-carotene, retinol and vitamin C values increased significantly but that MDA values decreased significantly. The results showed that all extracts have enhanced the antioxidant status and decreased the incidence of free radical-induced lipid peroxidation in blood samples of rats exposed to XR. However, the antioxidant effect of AHE-administered animals was more effective than that of MSE- and SOE-administered whole-body XR rats. We conclude that the supplementation with saponin-containing extracts may serve to reinforce the antioxidant systems, thus having protective effect against cell damage by XR. [source] | ||||||||||||||||