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At least 127 records · Page 7Linked to original sources

PubMed2005

Genetic isolation between two sympatric host plant races of the European corn borer, Ostrinia nubilalis Hubner. II: assortative mating and host-plant preferences for oviposition.

The European corn borer, Ostrinia nubilalis Hubner, colonized maize (Zea mays L.) after its introduction into Europe about 500 years ago and is now considered one of the main pests of this crop. In northern France, two sympatric host races have been described: one feeding on maize and the other on mugwort (Artemisia vulgaris L.) and hop (Humulus lupulus L.). In a previous study, we showed that mating between the two races may be impeded by differences in the timing of moth emergence and in the composition of the sex pheromone produced by the females. In this study, we further investigated the genetic isolation of these two races using strains from the maize (Z strain) and mugwort (E strain) races selected for diagnostic alleles at two allozyme loci. In a cage containing maize and mugwort plants and located in natural conditions, mating between individuals of the same strain occurred more often than mating between males and females of the E and Z strains. In particular, we obtained no evidence for crosses between Z females and E males. We also found that females of the Z strain laid their eggs almost exclusively on maize, whereas females of the E strain laid their eggs preferentially, but not exclusively, on mugwort. These results suggest that the genetic differentiation between the two host races may also be favored by host-plant preference, one of the first steps toward sympatric speciation.

Animals↗

PubMed2006

Open, non-controlled clinical studies to assess the efficacy and safety of a medical device in form of gel topically and intravaginally used in postmenopausal women with genital atrophy.

Menopause is often associated with vaginal atrophy and related symptoms, such as vaginal dryness, burning, itching, and dyspareunia, decrease in libido and in general a decrease in the quality of life. The common treatment up to the 1990's has been the oral hormone replacement therapy (HRT), but this treatment has been consequently re-considered due to its adverse effects. Topical estrogenic products have been subsequently developed to minimize the systemic adverse effects of the oral HRT, but they are still considered at risk in case of prolonged use. As an alternative, two clinical trials were performed to investigate the effects of a medical device in the form of a gel, containing hyaluronic acid, liposomes, phytoestrogens from Humulus lupulus extract, and Vitamin E, with the aim of testing its safety and efficacy in post-menopausal women with urogenital atrophy. The first pilot study confirmed in 10 women the good safety profile, both locally and systemically, of the device applied on the external genitals at the dose of 1-2 g/day for 30 days. The second study was carried out, according to a multicenter, open, non-controlled design, in 100 post-menopausal women assigned to the vaginal application of 2.5 g of gel/day for 1 week followed by two applications/week for 11 weeks. The primary end-point was the evaluation of vaginal dryness assessed by a Visual Analogue Scale both by the investigator and the subject. Secondary endpoints were the evaluation of all other symptoms and signs associated with atrophic vaginitis (itching, burning, dyspareunia, vaginal inflammation/oedema and rash assessed by a 4-point scale and presence of vaginal abrasions and disepithelialisation), and the recording of adverse events during the study. At the end of the treatment, an overall judgment on the efficacy and safety of the device was made by the investigator and a judgment on the acceptability of the treatment was made by the subjects. The results showed a marked effect of the tested product on the vaginal dryness and on all other symptoms and signs with statistically significant reductions since the first week of treatment. No treatment-related adverse events were complained by the subjects and the treatment course showed a high level of acceptability by the subjects. This device could be considered an effective and safe alternative treatment of genital atrophy in post-menopausal women, especially when HRT is not recommended.

Administration, Intravaginal↗

PubMed2006

Influence of xanthohumol on the binding behavior of GABAA receptors and their lateral mobility at hippocampal neurons.

The influence of the xanthohumol from Humulus lupulus L. on the binding of muscimol-Alexa Fluor 532 (Mu-Alexa), a fluorescently labeled GABAA receptor agonist, was studied by fluorescence correlation spectroscopy. An incubation of hippocampal neurons with 75 nM of xanthohumol increased the specific Mu-Alexa binding by approximately 17%, which was selectively found in GABAA receptor Mu-Alexa complexes with hindered lateral mobility [D(bound2) = (0.11 +/- 0.03) microm2/s] as described with midazolam.

Animals↗

PubMed2005

Mechanisms of the antiangiogenic activity by the hop flavonoid xanthohumol: NF-kappaB and Akt as targets.

Xanthohumol (XN), the principal flavonoid of the hop plant (Humulus lupulus L.) and a constituent of beer, has been suggested to have potential cancer chemopreventive activities. We have observed that most cancer chemopreventive agents show antiangiogenic properties in vitro and in vivo, a concept we termed "angioprevention." Here we show for the first time that XN can inhibit growth of a vascular tumor in vivo. Histopathology and in vivo angiogenesis assays indicated that tumor angiogenesis inhibition was involved. Further, we show the mechanisms for its inhibition of angiogenesis in vivo and related endothelial cell activities in vitro. XN repressed both the NF-kappaB and Akt pathways in endothelial cells, indicating that components of these pathways are major targets in the molecular mechanism of XN. Moreover, using in vitro analyses, we show that XN interferes with several points in the angiogenic process, including inhibition of endothelial cell invasion and migration, growth, and formation of a network of tubular-like structures. Our results suggest that XN can be added to the expanding list of antiangiogenic chemopreventive drugs whose potential in cancer prevention and therapy should be evaluated.

3T3 Cells↗

PubMed2004

Expression of lipoxygenase during organogenic nodule formation from hop internodes.

Study of lipoxygenase expression (LOX; EC 1.13.11.12) during organogenic nodule formation in hop (Humulus lupulus var. Nugget) showed that LOXs are developmentally regulated throughout the process, suggesting their involvement in the response of internodes to wounding, nodule formation, and plantlet regeneration from these nodules. LOX activity and lipid peroxides exhibited a huge increase during the first week of culture, which may indicate a role for LOX and LOX products in response to wounding in hop, as reported for other systems. Western blotting analysis showed a de novo synthesis of LOX isoenzymes in response to wounding and the detection of three different isoenzymes. Confocal analysis of LOX immunofluorescence revealed the presence of the enzyme in cortical cells of induced internodes and in prenodular cells, mostly appearing as cytoplasmic spots. Some of them were identified as lipid bodies by cytochemical and double immunofluorescence assays, suggesting the involvement of a lipid body LOX during nodule formation. Immunogold labeling detected LOX in peroxisomes, lipid bodies, and plastids of nodular cells. Quantification of the labeling density provided statistical significance for the localization of LOX (three different isoenzymes) in the three compartments, which suggested a possible involvement of LOX in metabolic functions of these organelles during organogenic nodule formation and plantlet regeneration.

Fluorescent Antibody Technique↗

PubMed2006

Effects of hop extracts on nasal rubbing and sneezing in BALB/c mice.

The effects of hop extracts (Humulus lupulus L.) on histamine release from rat peritoneal mast cells and human basophilic KU812 cells were studied. Hop water extract (HWE) and XAD-4 50% methanol fraction of HWE (MFH) inhibited histamine release from rat mast cells induced by compound 48/80 at concentrations of 100 and 10 mug/ml, respectively. Almost the same findings were observed with A23187-induced histamine release from KU812 cells. Next, we studied the effects of hop extracts on antigen-induced nasal rubbing and sneezing in sensitized BALB/c mice. HWE caused a significant inhibition of nasal rubbing and sneezing at a dose of 500 mg/kg. MFH also inhibited nasal rubbing and sneezing dose-dependently. A significant difference was observed from 100 mg/kg in nasal rubbing and 200 mg/kg in sneezing. The effects of both extracts became clear after repeated administration. HWE and MFH significantly inhibited both nasal rubbing and sneezing, respectively, after consecutive treatment for 15 d at smaller doses compared with single administration. This finding indicates that the active component of hop is included in MFH, which was absorbed to Amberlite XAD-4 and eluted with 50% methanol. These results clearly demonstrated that hop extracts may be effective in the relief of symptoms of allergic rhinitis.

Animals↗

PubMedDate not supplied

The first occurrence in nature of two compounds from hops.

Two compounds, (p-methoxyphenyl) diphenylmethanol (1) and tribenzylamine (2), were isolated from Humulus lupulus. Their structures were established on the basis of spectral evidence (MS, IR, NMR, HMBC, HMQC, 1H-1H COSY experiments). Compounds 1 and 2 were found as natural products at the first time.

Benzylamines↗

PubMed2006

The hop phytoestrogen, 8-prenylnaringenin, reverses the ovariectomy-induced rise in skin temperature in an animal model of menopausal hot flushes.

The mechanisms underlying menopausal hot flushes are poorly understood, although it is generally assumed they result from disturbances of thermoregulatory centres in the hypothalamus. 8-Prenylnaringenin (8-PN) has been identified as a potent phytoestrogen in hops (Humulus lupulus) and there are claims that hop-containing preparations can reduce hot flushes. We have investigated the site of action of 8-PN in a rat model of menopausal hot flushes, in which the tail skin temperature (TST) is increased after oestrogen withdrawal induced by ovariectomy. Daily s.c. administration of either 17beta-oestradiol (E2; 4 microg/kg) or 8-PN (400 microg/kg) significantly reduced the elevated TST after 2 days of treatment. Subcutaneous co-administration of either E2 or 8-PN with the oestrogen receptor (ER) antagonist, ICI 182,780 (200 microg/kg), which is thought not to cross the blood-brain barrier, completely blocked the effect of E2 and 8-PN on TST. The ERalpha- and ERbeta-specific agonists, 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (100 microg/kg) and 2,3-bis(4-hydroxyphenyl)-propionitrile (60 microg/kg) respectively, both significantly reversed the raised TST in ovariectomised rats. These observations suggest that the regulation of the vasomotor response by oestrogens and phytoestrogens is mediated, at least in part, by peripheral mechanisms involving both ERalpha and ERbeta.

Animals↗

PubMed2002

Cancer chemopreventive activity of Xanthohumol, a natural product derived from hop.

Characterization and use of effective cancer chemopreventive agents have become important issues in public health-related research. Aiming to identify novel potential chemopreventive agents, we have established an interrelated series of bioassay systems targeting molecular mechanisms relevant for the prevention of tumor development. We report anticarcinogenic properties of Xanthohumol (XN), a prenylated chalcone from hop (Humulus Iupulus L.) with an exceptional broad spectrum of inhibitory mechanisms at the initiation, promotion, and progression stage of carcinogenesis. Consistent with anti-initiating potential, XN potently modulates the activity of enzymes involved in carcinogen metabolism and detoxification. Moreover, XN is able to scavenge reactive oxygen species, including hydroxyl- and peroxyl radicals, and to inhibit superoxide anion radical and nitric oxide production. As potential antitumor-promoting mechanisms, it demonstrates anti-inflammatory properties by inhibition of cyclooxygenase-1 and cyclooxygenase-2 activity and is antiestrogenic without possessing intrinsic estrogenic potential. Antiproliferative mechanisms of XN to prevent carcinogenesis in the progression phase include inhibition of DNA synthesis and induction of cell cycle arrest in S phase, apoptosis, and cell differentiation. Importantly, XN at nanomolar concentrations prevents carcinogen-induced preneoplastic lesions in mouse mammary gland organ culture. Because XN is easily cyclized to the flavanone isoxanthohumol, activities of both compounds were compared throughout the study. Together, our data provide evidence for the potential application of XN as a novel, readily available chemopreventive agent, and clinical investigations are warranted once efficacy and safety in animal models have been established.

Animals↗

PubMed2002

[Systemic urticaria induced by hops].

The authors report a patient who presented 4 times a systemic urticaria with arthralgias and fever treated by corticosteroids with efficacy. Wild hop (Humulus lupulus) was finally proved to be the causal factor. H.L. belongs to the cannabinaceas family. Hop dermatitis in hop workers population is the main widely described clinical manifestation. Rhinitis, conjunctivitis, asthma are rare as soon as contact urticaria. IgE-anti Hop induced allergies are described in the literature. However, in some cases of reactions to hop the mechanisms are uncertain: toxicity--possible role of lupuline--or immunoallergic processus with immunocomplexes (IC) (with increased IC in serum) and systemic urticaria such as in our observation.

Aphonia↗

PubMed2002

Surveys of microfungi in a former industrial area in Duisburg-Nord.

One hundred and forty microfungi (Ascomycetes and Deuteromycetes) were collected in the "Landschaftspark Duisburg-Nord" located in North Rhine-Westphalia. New hosts for rarely found fungi are recorded for the first time. New for Germany are Massaria inquinans (Tode) De Not. and Nitschkia grevillei (Rhem) Nannf. on Acer pseudoplatanus L., Pirottaea nigrostriata Graddon on Artemisia vulgaris L., Ceratopycnis clematidis Höhn. on Clematis vitalba L., Dasyscyphus aff. humuli (W. Phillips) Dennis on Humulus lupulus L. and Leptosphaeria derasa (Berk. & Br.) Auersw. on Senecio inaequidens DC. New for North Rhine-Westphalia are Chaetosphaerella phaeostroma (Durieu & Mont.) E. Müller & Booth and Phomopsis platanoides (Cooke) Died. on Acer pseudoplatanus L., Microsphaeropsis pseudaspera Sutton, Mycosphaerella osborniae D. Hawksw. & Sivan. and Phomopsis oblita Sacc. on Artemisia vulgaris L., Leptosphaeria acuta (Fr.) P. Karst. and Leptosphaeria doliolum (Pers.) Ces. & De Not. on Bryonia dioica Jacq., Ophiobolus erythrosporus (Riess) G. Winter and Pleospora herbarum (Pers.) Rabenh. ex Ces. & De Not. on Dipsacus sylvestris (Huds), Keissleriella ocellata (Niessl) Bose on Hypericum perforatum L., Dactylaria aff. graminicola on Lolium perenne L., Siroplacodium aff. atrum on Oenothera beinnis L., Diatrypella favacea (Fr.) Sacc. on Prunus spec., Hapalosphaeria deformans (Syd.) Syd. and Microdiscula rubicola (Bres.) Höhn. on Rubus fructicosus agg. L., Cryptodiaporthe salicina (Pers.) Wehm. on Salix alba L. and Pleurophoma pleurospora (Sacc.) Höhn. on Salix caprea L.

Acer↗

PubMed2004

Exposure of hop growers to bioaerosols.

Air sampling was performed during picking and sorting of hop (Humulus lupulus) cones on 19 hop farms located in eastern Poland. The concentration and composition of airborne microflora and the concentration of airborne dust and endotoxin were determined. Additionally, 7 samples of settled hop dust were collected and examined for the presence of microorganisms and endotoxin. Total concentrations of airborne microorganisms were within a range of 2.08-129.58 x 10(3) cfu/m(3). Gram-positive bacteria formed 22.2-96 % of the total count. Among them, prevailed corynebacteria and endospore-forming bacilli. Fungi constituted 3.7-65.4 % of the total count. The dominant species were Penicillium citrinum, Alternaria alternata, and Cladosporium epiphyllum. Thermophilic actinomycetes and Gram-negative bacteria were detected in the air of only 10 and 6 farms, respectively. Airborne dust concentrations at the workplace ranged from 0.17-31.67 mg/m(3). The concentrations of airborne endotoxin were in the range of 26-6250 ng/m(3). In the samples of settled dust, the concentrations of total microorganisms ranged from 0.25 x 10(6) to 2.87 x 10(8) cfu/g. Gram-positive and Gram-negative bacteria constituted respectively 3.2-98 % and 0-93.5 % of the total count. Fungi formed 0-30.3 % of the total count. The most common species were Penicillium spp. and Alternaria alternata. The concentrations of endotoxin were in the range of 312.5-6250 microg/g (median 6250 microg/g). The presence of microorganisms and endotoxin in the samples of settled dust was confirmed by electron microscopy. The hop growers seem to be exposed to lower concentrations of dust, microorganisms and endotoxin compared to other branches of agriculture. This may be partly due to antimicrobial properties of hop plant. Among microbial factors associated with hop dust, bacterial endotoxin and allergenic fungi pose the greatest potential hazard for exposed hop farmers.

Aerosols↗

PubMed2003

Health effects of inhalation exposure to organic dust in hops farmers.

Medical examinations were performed in a group of 23 hops farmers exposed to organic dust from hop (Humulus lupulus). The examinations took place in individual farms during harvesting, sorting and transporting of hop cones. As a reference group, 50 urban dwellers not exposed to organic dust were examined. There were conducted physical examinations, interviews concerning the occurrence of respiratory disorders and work-related symptoms, lung function tests, determination of cytokines concentrations, and allergological tests comprising skin prick test with 4 microbial antigens associated with organic dust, precipitin test with 12 microbial antigens, and a test for inhibition of leukocyte migration. Five farmers (21.7%) reported occurrence of work-related symptoms, including dry cough and dyspnoea. Eight farmers (34.8%) reported symptoms of chronic bronchitis. Mean spirometric values were within normal ranges. The farmers showed positive responses in precipitin test and test for inhibition of leukocyte migration to antigens of environmental microbes, mainly to the antigen of Gram-negative bacterium Pantoea agglomerans. The results showed a potential risk of occupational respiratory diseases in the population of hops farmers.

Adult↗

PubMed2006

Identification of individual herbal drugs in tea mixtures using restriction analysis of ITS DNA and real-time PCR.

We have studied a sedative tea made of Valerianae radix (Valeriana officinalis L.), Lupuli strobuli (Humulus lupulus L.), Melissae folium (Melissa officinalis L.) and Menthae piperitae folium (Mentha piperita L.). In order to identify the constituent drugs a method was established involving amplification of the internal transcribed spacers (ITS) region of nuclear ribosomal DNA on the basis of restriction analysis and real-time PCR. ITS regions of individual drugs were amplified and sequenced. Restriction analysis was performed with selected restriction endonucleases Nae I, PshA I and Xcm I. Real-time PCR was carried out, using primers specifically designed for each individual herbal drug. Real-time PCR proved to be a method for identifying individual herbal drugs in a tea mixture with a single DNA extraction in a single PCR run, since its limit of detection is lower than that for restriction analysis.

DNA Fingerprinting↗

PubMed2000

Biotransformation of monoterpene alcohols by Saccharomyces cerevisiae, Torulaspora delbrueckii and Kluyveromyces lactis.

Monoterpenoids are important flavour compounds produced by many plant species, including grapes (Vitis vinifera) and hops (Humulus lupulus). Biotransformation reactions involving monoterpenoids have been characterized in filamentous fungi, but few examples have been observed in yeasts. As monoterpenoids are in contact with yeasts during beer and wine production, biotransformation reactions may occur during the fermentation of these beverages. This paper describes the biotransformation of monoterpene alcohols, of significance in the alcoholic beverage industries, by three yeast species. All three species analysed had the ability to convert monoterpenoids. Saccharomyces cerevisiae and Kluyveromyces lactis reduced geraniol into citronellol, whilst all three yeasts produced linalool from both geraniol and nerol. Monocyclic alpha-terpineol was formed from both linalool and nerol, by all three yeasts. alpha-Terpineol was then converted into the diol cis-terpin hydrate. K. lactis and Torulaspora delbrueckii also had the ability to form geraniol from nerol. Finally, the stereospecificity of terpenoid formation was analysed. Both (+) and (-) enantiomers of linalool and alpha-terpineol were formed in roughly equal quantities, from either geraniol or nerol.

Acyclic Monoterpenes↗

PubMed2001

Incidence and inheritance of resistance to METI-acaricides in European strains of the two-spotted spider mite (Tetranychus urticae) (Acari: Tetranychidae).

A strain of Tetranychus urticae (Koch; Acari: Tetranychidae), collected from hops (Humulus humuli L; Cannabaceae) in England with a short history of tebufenpyrad use, exhibited resistance to four METI (mitochondrial electron transport inhibitor)-acaricides; tebufenpyrad, pyridaben, fenazaquin and fenpyroximate. Resistance factors for these compounds in a microimmersion assay were 46, 346, 168 and 77 respectively, and corresponded to those exhibited by a Japanese METI-acaricide-resistant reference strain. Levels of resistance remained stable without further selection, and selection with tebufenpyrad did not increase them. The UK strain was also resistant (c 6-fold) to bifenthrin. Crosses of homozygous, diploid females with hemizygous, haploid males showed that, in the UK strain, METI-acaricide resistance was paternally and maternally inherited, and was an incompletely dominant trait. Another tebufenpyrad-resistant strain from the UK, originating from a chrysanthemum nursery (Chrysanthemum foeniculaceum Giseke; Asteraceae) was collected eight months later at a site c 210 km distant from the first. These are the first published incidences of METI-acaricide resistance in Europe and implications for the future use of these compounds are discussed.

Animals↗

PubMed2005

Diversity of the exoproteome of Fusarium graminearum grown on plant cell wall.

The exoproteome of the fungus Fusarium graminearum grown on glucose and on hop (Humulus lupulus, L.) cell wall has been investigated. The culture medium was found to contain a higher quantity of proteins and the proteins are more diverse when the fungus is grown on cell wall. Using both 1D and 2D electrophoresis followed by mass spectrometry analysis and protein identification based on similarity searches, 84 unique proteins were identified in the cell wall-grown fungal exoproteome. Many are putatively implicated in carbohydrate metabolism, mainly in cell wall polysaccharide degradation. The predicted carbohydrate-active enzymes fell into 24 different enzymes classes, and up to eight different proteins within a same class are secreted. This indicates that fungal metabolism becomes oriented towards synthesis and secretion of a whole arsenal of enzymes able to digest almost the complete plant cell wall. Cellobiohydrolase is one of the only four proteins found both after growth on glucose and on plant cell wall and we propose that this enzyme could act as a sensor of the extracellular environment. Extensive knowledge of this very diverse F. graminearum exoproteome is an important step towards the full understanding of Fusarium/plants interactions.

Cell Wall↗

PubMed2006

The combination of gas chromatography-olfactometry and multidimensional gas chromatography for the characterisation of essential oils.

A research area of great interest to the flavour industry is the analysis of odour active compounds in essential oils. In this paper, a methodology is presented for the identification of character-impact odorants in essential oil samples using (a) gas chromatography-olfactometry (GC-O); (b) comprehensive two-dimensional gas chromatography (GC x GC) combined to time-of-flight mass spectrometry (TOFMS) and (c) heart-cut multidimensional gas chromatography-olfactometry (MDGC-O). The specific advantages and limitations of each technique are discussed. The advantage of combining these techniques in a strategy to identify character-impact odorants is demonstrated using examples from coriander leaf (Coriandrum sativum) and hop (Humulus lupulus) essential oils. In particular, resolution of co-eluting regions of compounds and evaluation of their individual odour activity is discussed. In coriander leaf, only E-2-dodecenal was found to contribute to a co-eluting odour region, E-2-dodecen-1-ol and 1-dodecanol being present below detection threshold. Using MDGC on a hop essential oil sample, eight significant peaks were resolved from an 18 s heart-cut where a potent odorant was perceived during GC-O.

Chromatography, Gas↗