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At least 55 records · Page 3Linked to original sources
PubMed1999

MADS-box genes active in developing pollen cones of Norway spruce (Picea abies) are homologous to the B-class floral homeotic genes in angiosperms.

The reproductive organs of conifers, the pollen cones and seed cones, differ in morphology from the angiosperm flower in several fundamental respects. In this report we present evidence to suggest that the two plant groups, in spite of these morphological differences and the long evolutionary distance between them, share important features in regulating the development of the reproductive organs. We present the cloning of three genes, DAL11, DAL12, and DAL13, from Norway spruce, all of which are related to the angiosperm B-class of homeotic genes. The B-class genes determine the identities of petals and stamens. They are members of a family of MADS-box genes, which also includes C-class genes that act to determine the identity of carpels and, in concert with B genes specify stamens in the angiosperm flower. Phylogenetic analyses and the presence of B-class specific C-terminal motifs in the DAL protein sequences imply homology to the B-class genes. Specific expression of all three genes in developing pollen cones suggests that the genes are involved in one aspect of B function, the regulation of development of the pollen-bearing organs. The different temporal and spatial expression patterns of the three DAL genes in the developing pollen cones indicate that the genes have attained at least in part distinct functions. The DAL11, DAL12, and 13 expression patterns in the pollen cone partly overlap with that of the previously identified DAL2 gene, which is structurally and functionally related to the angiosperm C-class genes. This result supports the hypothesis that an interaction between B- and C-type genes is required for male organ development in conifers like in the angiosperms. Taken together, our data suggests that central components in the regulatory mechanisms for reproductive organ development are conserved between conifers and angiosperms and, thus, among all seed plants.

Amino Acid Sequence↗
PubMed2000

Time measurement and the control of flowering in plants.

Many plants are adapted to flower at particular times of year, to ensure optimal pollination and seed maturation. In these plants flowering is controlled by environmental signals that reflect the changing seasons, particularly daylength and temperature. The response to daylength varies, so that plants isolated at higher latitudes tend to flower in response to long daylengths of spring and summer, while plants from lower latitudes avoid the extreme heat of summer by responding to short days. Such responses require a mechanism for measuring time, and the circadian clock that regulates daily rhythms in behaviour also acts as the timer in the measurement of daylength. Plants from high latitudes often also show an extreme response to temperature called vernalisation in which flowering is repressed until the plant is exposed to winter temperatures for an extended time. Genetic approaches in Arabidopsis have identified a number of genes that control vernalisation and daylength responses. These genes are described and models presented for how daylength might regulate flowering by controlling their expression by the circadian clock. BioEssays 22:38-47, 2000.

Acclimatization↗
PubMed2000

Evolutionary developmental genetics of floral symmetry: the revealing power of Linnaeus' monstrous flower.

Actinomorphic flowers have several planes of reflectional symmetry while zygomorphic flowers have just one. In a number of independent cases, actinomorphic flowers have arisen from zygomorphic ones during evolution. A famous example, studied by Linnaeus, is an actinomorphic variety of the common toadflax Linaria vulgaris. It has been shown now that this mutant carries a defect in LCYC, a homolog of the CYC gene, which controls zygomorphy in Antirrhinum majus.((1)) Interestingly, the mutant phenotype is not due to changes in the LCYC nucleotide sequence but rather to an extensive, heritable methylation of the gene.((1)) A second gene controlling zygomorphy in snapdragon, DICH, has recently also been shown to be a CYC homolog and both genes share significant sequence similarity with TB1, one of the key genes of maize domestication. The respective family of genes, probably encoding transcription factors, might thus become both a useful instrument and a target of future plant evolutionary developmental genetics.

Biological Evolution↗
PubMed1999

The effects of some herbs on the activities of thermophilic dairy cultures.

In this study, the effects of some herbs (Allium sp., Thymus sp., Anhriscus sp. and Ferule sp.) on growth and acid production of thermophilic cultures (Streptococcus thermophilus and Lactobacillus bulgaricus) were determined. The herbs were sterilized with gamma radiation and added to fermentation media at concentrations of 0.5, 1, 2 and 3% (w/w). Control medium was without herb. Results showed that increasing herb concentrations stimulated acid production by Streptococcus thermophilus and Lactobacillus bulgaricus.

Allium↗
PubMed1999

Antibacterial activity of Orobanche cernua extract.

The effect of the parasitic plant Orobanche cernua extract was evaluated on 5 different Gram-positive and Gram-negative bacteria. Dilution experiments show that the minimum inhibitory concentration (MIC; microgram/ml) of the extract was as follows: Staphylococcus aureus-1526.5; Streptococcus sp.-3125; Streptococcus pyogenes-25,000 and both for Bacillus cereus and Escherichia coli-50,000 micrograms/ml. Data indicated that the MIC of 3125 micrograms/ml is equal to cefotaxime (30 micrograms) and tobromycin (10 micrograms) activity against Streptococcus sp. and S. aureus, respectively; 25,000 and 50,000 micrograms/ml is equal to cefotaxime (30 micrograms) activity against S. pyogenes and B. cereus, respectively, and 50,000 micrograms/ml is equal to nalidixic acid (30 micrograms) activity against E. coli. It can be concluded that the O. cernua extract displays remarkable activity against some Gram-positive bacteria such as Streptococcus and Staphylococcus.

Anti-Bacterial Agents↗
PubMed1999

Phytotoxic lignans of Leucophyllum frutescens.

Bioassay-guided fractionation of the hexane:ethyl acetate (1:1) extract of the leaves of Leucophyllum frutescens (Berl.) I.M.Johnst (Scrophulariaceae) led to the isolation of its phytotoxic constituents diayangambin (1), epiyangambin (2), diasesartemin (3) and epiashantin (4). Phytotoxicity was demonstrated as inhibition of seed germination of Agrostis stolonifera cv. penncross (Poaceae) and inhibition of development of Lactuca sativa L. (Asteraceae) seedlings in a microassay using 24-well plates. Compound 1 was the most phytotoxic to L. sativa, showing strong inhibitory activity at 110 microM. Compound 1 was more active than 2 and 3 in inhibiting the growth of A. stolonifera with I(50) values of 160, 670 and 930 microM, respectively. At a concentration of 500 microM, these compounds inhibited all phases of onion root cell division. This is the first demonstration of antimitotic activity of these furofuran lignans, and the first report of their isolation from this species.

Germination↗
PubMed1979

Interaction of factors associated with cancer of the nasopharynx.

A retrospective study of nasopharyngeal carcinoma (NPC) revealed that smoking, working under poor ventilation, use of nasal balms or oil for nasal and throat troubles, use of herbal drugs, and anti-EBV antibody titer were found statistically associated. The dural interactions of these factors to the risk of NPC were presented. Except in work conditions with poor ventilation and when herbal drugs are used, all the combinations were synergistic. The synergistic actions were especially remarkable with smoking and other factors. The possible etiological mechanisms of NPC are discussed.

Antibodies, Viral↗
PubMed2000

Influence of mate drinking, hot beverages and diet on esophageal cancer risk in South America.

To estimate the effects of consuming hot beverages, including mate (an infusion of the herb Ilex paraguayensis), tea, coffee and coffee with milk, and other food items on esophageal cancer risk, we analyzed data from 830 cases and 1,779 controls participating in a series of 5 hospital-based case-control studies of squamous-cell carcinoma of the esophagus conducted in high-risk areas of South America. After adjusting for the strong effects of tobacco and alcohol consumption, both heavy mate drinking (>1 l/day) and self-reported very hot mate drinking were significantly associated with esophageal cancer risk in men and women. The magnitude and strength of the association for mate amount and, to a lesser extent, mate temperature were higher for women than men. The joint effects of mate amount and mate temperature were more than multiplicative, following a statistically significant synergistic interaction (p = 0.02) which was particularly evident among heavy drinkers (>1.50 l/day) of very hot mate (odds ratio = 4.14, 95% confidence interval: 2.24-7.67) compared to light drinkers (<0.50 l/day) of cold/warm/hot mate. Consumption of other very hot beverages, such as tea and coffee with milk but not coffee alone, was also significantly associated with an increased risk, in the 2- to 4-fold range. Statistically significant protective associations were identified for high consumption of vegetables, fruits, cereals and tea. In contrast, frequent consumption of meat, animal fats and salt was associated with a moderately increased risk. This pooled analysis adds evidence for a carcinogenic effect of chronic thermal injury in the esophagus induced by the consumption of very hot drinks, including mate. Our study further confirms the protective effect of a dietary pattern characterized by daily consumption of fruits and vegetables and low consumption of meat and animal fats.

Aged↗
PubMedDate not supplied

Controlling hyperhydration of carnations (Dianthus caryophyllus L.) grown in a mist reactor.

Carnations (Dianthus caryophyllus L.) grown in vitro often develop physiological abnormalities such as hyperhydration. The amount of hyperhydration and growth was compared between carnations grown in mist reactors and conventional semisolid micropropagation systems (vented or unvented GA7 culture boxes). Plants grown in the mist reactor with long misting times (10 min h(-1)) produced more dry mass than those grown with <10 min h(-1); however, more misting also produced more hyperhydrated plants (70% hyperhydration). Control of hyperhydration in the mist reactor involved either reducing the overall nutrient mist supply or altering the mist supply throughout the culturing period. Stepped decreases in the mist supply throughout the 3-week period or an overall decrease in the duration of misting reduced hyperhydration to 13% and 5%, respectively. However, for both misting regimes, the biomass of normal (healthy) plants (fresh and dry weights) was limited. Further analysis suggested that, although normal plant biomass increased with longer mist exposure, hyperhydration levels also increased while the water content, based on percent dry weight, approached that of hyperhydrated plants. Sufficient normal plant development (fresh weight, leaf and shoot numbers, height, and rooting) with < 50% hyperhydration was obtained by weekly, stepped increases in the nutrient mist supply.

Bioreactors↗
PubMed2000

Isolation of 5 alpha- and 5 beta-dihydrorubrosterone from Silene otites L. (Wib).

5 alpha-Dihydrorubrosterone (2 beta, 3 beta, 14 alpha, 17 beta-tetrahydroxy-5 alpha-androst-7-ene-6-one), a new 19-carbon 5 alpha-ecdysteroid, was isolated together with its 5 beta counterpart from the aerial parts of Silene otites L. (Wib.) (Caryophyllaceae) by a combination of solvent partition, low-pressure column chromatography, thin-layer chromatography (normal-phase and reversed-phase) and finally HPLC. Mass spectrometry and nuclear magnetic resonance spectroscopic procedures were used for compound characterization.

17-Ketosteroids↗
PubMed2000

Separation and determination of strychnine and brucine in Strychnos nux-vomica L. and its preparation by capillary zone electrophoresis.

A capillary zone electrophoresis method was developed for the separation and determination of strychnine and brucine in Strychnos nux-vomica L. and its preparation. The factors that could affect the separation were studied, such as the types and concentrations of electrolytes, pH, ionic strength and organic modifier. The optimum running buffer was 20 mmol/L of ammonium acetate containing 0.2 mol/L of glacial acetic acid (pH 3.64). The applied voltage was 25 kV and the wavelength of the UV detector was set at 214 nm. The established method with dopamine hydrochloride as internal standard was linear in the range of 5-100 microg/mL for both strychnine and brucine. The recovery was 102.96% for strychnine and 98.56% for brucine. The extracts of Strychnos nux-vomica and its preparation could be directly injected for analysis.

Buffers↗
PubMed2000

Antioxidants in medicinal plant extracts. A research study of the antioxidant capacity of Crataegus, Hamamelis and Hydrastis.

The antioxidant capacity of extracts of Crataegus oxyacantha, Hamamelis virginiana, Hydrastis canadensis, plants native to Europe and North America which have long been used in herbal medicine for the treatment of cardiac and circulatory functions, has been investigated. The total antioxidant potential conferred by all hydrogen donating antioxidants present in these extracts has been assessed by the ABTS assay and the relative order of antioxidant potential has been established. Gas chromatography coupled to mass spectrometry (GC-MS) has been used for the chemical identification of the antioxidant volatile compounds present in the extracts. The GC-MS data were related to the results obtained using the ABTS assay.

Antioxidants↗
PubMed2001

Determination of the presence of antioxidants deriving from sage and oregano extracts added to animal fat by means of assessment of the radical scavenging capacity by photochemiluminescence analysis.

Herbs and their extracts with antioxidant capacity could be used directly as stabilisers of fat and indirectly as feed additives, in order to improve quality and shelf-life of meat and fat-containing food. In this work a sensitive analytical method is proposed for determination of the antioxidant activity measured by photochemiluminescence (PCL) in lard stabilised with extracts of sage (Salvia officinalis L.) or oreganum (Origanum vulgare L.). A prior step of purification of fat samples is required, in order to separate and concentrate the phenolics from lipidic substances. The method was validated by determination of recovery rate and repeatability. In addition fat samples originating from pigs fed with feed additives of Salviae folium or Origani herba were analysed to investigate the supposed antioxidative effects, that could increase the shelf-life of meat products. In contrast with lard mixed with extracts of sage or oregano, back fat samples originating from pigs fed with feed additives of the same herbs didn't show a higher antioxidant activity than the control group. On the one hand it seems possible to keep perishable fat-containing food longer by an addition of an extract of sage or oregano due to their antioxidative properties, on the other hand administration of feed additives of dried herbs to pigs had no effect on quality and shelf-life of fat obtained from these animals.

Animals↗
PubMed2001

Production of alpha-amylase with Aspergillus flavus on Amaranthus grains by solid-state fermentation.

The effects of the ingredients of the Rajgeera (Amaranthus paniculatas) medium designed for production by A. flavus was evaluated with the help of the fractional factorial method, 'The Plackett-Burman' design. Out of the fifteen medium components used in the design, four components, viz., corn steep liquor, ammonium hydrogen phosphate, sodium chloride and calcium chloride were selected based on the contrast coefficient values and further used as independent variables in the 'Box-Behnken' design. A polynomial multiple regression model was generated using the SPSS/PC + (version 7.5) statistical analysis package. Corn steep liquor, ammonium hydrogen phosphate, sodium chloride and calcium chloride contributed to the yield to the tune of 81.3% of which sodium chloride and calcium chloride affected the yield to the tune of 68.3%. The yield obtained from the optimized medium was 8 times that obtained from the original medium. Amaranthus paniculatas grains as a source of starch and carbon for production of alpha-amylase under solid-state fermentation has been studied for the first time.

Aspergillus flavus↗
PubMed2001

Metabolism of the herbicide glufosinate-ammonium in plant cell cultures of transgenic (rhizomania-resistant) and non-transgenic sugarbeet (Beta vulgaris), carrot (Daucus carota), purple foxglove (Digitalis purpurea) and thorn apple (Datura stramonium).

The metabolism of the herbicide glufosinate-ammonium was investigated in heterotrophic cell suspension and callus cultures of transgenic (bar-gene) and non-transgenic sugarbeet (Beta vulgaris). Similar studies were performed with suspensions of carrot (Daucus carota), purple foxglove (Digitalis purpurea) and thorn apple (Datura stramonium). 14C-labelled chemicals were the (racemic) glufosinate, L-glufosinate, and D-glufosinate, as well as the metabolites N-acetyl L-glufosinate and 3-(hydroxymethylphosphinyl)propionic acid (MPP). Cellular absorption was generally low, but depended noticeably on plant species, substance and enantiomer. Portions of non-extractable residues ranged from 0.1% to 1.2% of applied 14C. Amounts of soluble metabolites resulting from glufosinate or L-glufosinate were between 0.0% and 26.7% of absorbed 14C in non-transgenic cultures and 28.2% and 59.9% in transgenic sugarbeet. D-Glufosinate, MPP and N-acetyl L-glufosinate proved to be stable. The main metabolite in transgenic sugarbeet was N-acetyl L-glufosinate, besides traces of MPP and 4-(hydroxymethylphosphinyl)butanoic acid (MPB). In non-transgenic sugarbeet, glufosinate was transformed to a limited extent to MPP and trace amounts of MPB. In carrot, D stramonium and D purpurea, MPP was also the main product; MPB was identified as a further trace metabolite in D stramonium and D purpurea.

Aminobutyrates↗