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At least 649 records · Page 36Linked to original sources
PubMed2002

Semiochemical-mediated flight responses of sap beetle vectors of oak wilt, Ceratocystis fagacearum.

The sap beetle, Colopterus truncatus (Coleoptera: Nitidulidae), is one of the primary vectors of the oak wilt pathogen, Ceratocystis fagacearum, in the north-central United States. Field behavioral assays utilizing various release rates and blends of three methyl-branched hydrocarbon aggregation pheromone components showed that flight responses of this beetle were similar in Illinois and Minnesota populations. In both locations, both sexes of the beetle responded synergistically to a combination of the three-component pheromone and fermenting whole-wheat bread dough. Further, Colopterus truncatus preferred a high release rate over a low release rate of the three-component blend. In both locations, the response of C. truncatus to a simplified version of the pheromone consisting of (2E,4E,6E)-3,5-dimethyl-2,4,6-octatriene (1) and (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-decatetraene (3) was not significantly different from the response to the three-component blend. An experiment in Illinois with all possible combinations of the components demonstrated that the decatetraene (3) was the crucial component in the blend; of all treatments, the maximal response was elicited by 3 + dough. Chipped bark, phloem, and xylem from northern pin oak, Quercus ellipsoidalis, was not attractive to C. truncatus in Minnesota. During a weekly survey over two seasons in Minnesota, C. truncatus flew in response to the three-component pheromone between early April and early July, with the maximum responses coming on May 4, 2000 and April 20, 2001. During both years, more than 98% of the beetles were trapped between April 14 and June 1. During the same survey, Glischrochilus spp. (Nitiduildae) flew during longer periods of the summer, particularly in 2001. The sex ratio of C. truncatus responding during all experiments was female-biased (1.8:1, female-male), which is characteristic of other male-produced coleopteran aggregation pheromones. Other sap beetles that play a minor role in the pathobiology of C. fagacearum also responded in experiments conducted in Minnesota. Carpophilus brachypterus Say was cross-attracted to the two- and three-component blends of the C. truncatus pheromone and dough, whereas two Glischrochilus spp. were attracted to all treatments that contained dough.

Animals↗
PubMed2001

Short-term changes in consumption and oviposition rates of Neoseiulus californicus strains (Acari: Phytoseiidae) after a diet shift.

Short-term effects on consumption and oviposition rates of four strains of Neoseiulus californicus (McGregor) after a diet shift were evaluated. The new feeding conditions experienced by the predators were six fixed densities of eggs or protonymphs of Tetranychus urticae Koch placed on excised strawberry leaflet discs and maintained under laboratory conditions (25 +/- 1 degrees C, 75-85% RH, 16L: 8D). The observations were made on the first and the fifth day of the experiment. The phytoseiids came from three long-term mass-reared strains fed on T. urticae, Dermatophagoidesfarinae Hughes, or Quercus spp. pollen, respectively. The fourth strain was collected directly in a strawberry field. Time since diet transfer can be added to the factors (i.e. feeding history and prey density) already known to affect the functional and numerical responses of N. californicus, both when it feeds on prey eggs and protonymphs. If consumption rates were averaged over all strains and densities, 9.04 and 11.41 eggs, and 6.97 and 6.48 protonymphs were consumed on the first and the fifth day, respectively. If the same was done for oviposition rates, predators feeding on eggs produced 1.46 and 2.36 eggs/female/day, whereas predators feeding on protonymphs produced 1.35 and 2.29 eggs/female/day. Time had the greatest impact on the functional response of the strain that had previously fed on tetranychids, while an effect of time on the numerical response was detectable in all strains.

Animals↗
PubMed2002

Comparison of different methods for lignin determination as a basis for calibration of near-infrared reflectance spectroscopy and implications of lignoproteins.

Three commonly employed methods for lignin determination, i.e., the thioglycolic acid (TGA), the acetylbromide (AB), and the acid detergent fiber (ADF) method, were compared using leaves and xylem tissue from five species (Nicotiana tabacum, Populus x canescens, Fagus sylvatica, Quercus robur, and Picea abies). In each case, cell walls were isolated before lignin determination. Each of the three methods estimated a different lignin concentration in a given tissue, except for spruce wood. The "lignin" concentration determined with the AB method was strongly dependent on whether or not the cell walls were subjected to alkaline hydrolysis to remove covalently bound aromatic nonligneous components before lignin determination. Lignin concentrations determined in hydrolyzed cell walls of different tissues and species by the AB method showed a good correlation with those obtained by the TGA method and, thus, were convertible. In contrast, gravimetrically estimated ADF lignins did not or only moderately correlate with lignins measured with methods based on the UV absorbance of the solubilized lignin degradation products. Leaves of a given species generally contained higher ADF-lignin concentrations than the corresponding stem tissue. Both ADF and TGA lignin data of beech were used to calibrate near-infrared reflectance spectra (NIRS) for lignin prediction. Both NIRS calibration procedures gave good statistical fits with correlation coefficients close to 1, indicating that TGA and ADF lignin concentrations of beech can be estimated by NIRS with high accuracy. However, the two calibrations were based on different empirical terms, showing that TGA and ADF lignins did not share the same physical basis for calibration. C/N analysis revealed the presence of 3.1 and 1.4% nitrogen in ADF lignins of beech leaves and wood, respectively. The major fraction of this nitrogen was recovered in amino acids, which corresponded to 14% and 3% protein in ADF lignins of leaves and wood, respectively. These results show that ADF lignins contain significant concentrations of lignin-bound proteins, which renders this method unsuitable to determine genuine lignin.

Calibration↗
PubMed2003

Detecting differences in crown transparency assessments between countries using the image analysis system CROCO.

Estimates of crown transparency calculated using the semi-automatic image analysis system CROCO were compared with the visual estimates of survey teams from 12 European countries. For each of five European species (Norway spruce (Picea abies (L.) Karst.), silver fir (Abies alba Mill.), Scots pine (Pinus sylvestris L.), beech (Fagus sylvatica L.), oak (Quercus robur L.)) 15 trees were assessed. In 64% of the comparisons, CROCO estimates and the survey teams' scores differed significantly, while differences between countries were significant in 58% of all comparisons. We calculated Spearman's rank correlation and the standard deviation of the differences between CROCO and each country and between pairs of countries. We then computed the medians for CROCO and each country. CROCO and only a few countries had for all species a higher median correlation and lower median standard deviation than the median for the comparison between countries. In addition no country had a consistently higher correlation or lower standard deviation than CROCO. We conclude that CROCO can provide more consistent and less variable estimates of crown transparency than visual assessments and that it can serve as a reference to detect differences in visual transparency assessments between countries over time.

Air Pollutants↗
PubMed2003

A new species of Protoachlya Upadhyay & Khulbe.

Protoachlya nainitalensis isolated from mixed oak forest soil (Quercus leucotrichophora & Q. floribunda) is described herein. The species is characterised by elongated, cylindrical, smooth walled zoosporangia; spherical and smooth walled oogonia with androgynous and rarely diclinous branches of antheridia. A simplified key of the known Protoachlya species has also been established.

India↗
PubMed2002

Genetic differentiation among host-associated Alebra leafhoppers (Hemiptera: Cicadellidae).

The limited importance ascribed to sympatric speciation processes via host race formation is partially due to the few cases of host races that have been reported among host populations. This work sheds light on the taxonomy of Alebra leafhoppers and examines the possible existence of host races among host-associated populations. The species of this genus show varying degrees of host association with deciduous trees and shrubs and, frequently, host populations of uncertain taxonomic status coexist and occasionally become pests. Allozyme electrophoresis of 21 Greek populations including sympatric, local and geographically distant samples collected on 13 different plant species, show that they represent at least five species: A. albostriella Fallén, A. viridis (Rey) (sensu Gillham), A. wahlbergi Boheman and two new species. Of these, one is associated to Quercus frainetto and other is specific to Crataegus spp. Significant genetic differences among sympatric and local host populations were found only in A. albostriella, between populations on Turkey oak, beech and common alder. It is suggested that the last two of these host populations may represent different host races. The results show that both the host plant and geographical distance affect the patterns of differentiation in the genus. The formation of some species seems to have been the result of allopatric speciation events while, for others, their origin can be equally explained either by sympatric or allopatric speciation.

Alleles↗
PubMed2004

Two-generation analysis of pollen flow across a landscape V: a stepwise approach for extracting factors contributing to pollen structure.

Patterns of pollen dispersal are central to both the ecology and evolution of plant populations. However, the mechanisms controlling either the dispersal process itself or our estimation of that process may be influenced by site-specific factors such as local forest structure and nonuniform adult genetic structure. Here, we present an extension of the AMOVA model applied to the recently developed TWOGENER analysis of pollen pool structure. This model, dubbed the Stepwise AMOVA (StAMOVA), focuses on determining to what extent ecological, demographic, and/or environmental factors influence the observed genetic variation in spatially separated pollen pools. The analysis is verified for efficacy, using an extensive battery of simulations, illustrating: (1) how nonuniform adult genetic structure influences the differentiation of spatially separated pollen pools, and (2) how effectively the Stepwise analysis performs in carrying out the appropriate corrections. Finally, the model is applied to a Quercus alba data set, from which we have prior evidence that the adult genetic structure is nonuniformly distributed across the sampling landscape. From this data set, we show how the Stepwise model can be applied to remove the effects of spatial adult genetic structure on pollen pool differentiation and contrast these results with those derived from the original TWOGENER analysis.

Genetics, Population↗
PubMed1991

Enzymic synthesis of 1-O-(indol-3-ylacetyl)-beta-D-glucose. Purification of the enzyme from Zea mays, and preparation of antibodies to the enzyme.

The enzyme indol-3-ylacetylglucose synthase (UDP-glucose:indol-3-ylacetate beta-D-glucosyltransferase) catalyses the reaction: [formula: see text] This is the first step in the series of reactions leading to the indol-3-ylacetic acid conjugates found in maize. Previous attempts to purify this enzyme from the liquid endosperm of kernels of Zea mays (sweet corn) were not entirely successful owing to the lability of partially purified preparations during column chromatography. Thus this enzyme has not previously been purified to homogeneity. During the present study it was found that retention of enzyme activity required the combined presence of glycerol and dithiothreitol. Adding these requirements permitted purification of the enzyme to homogeneity with retention of catalytic activity. These purified preparations were used for preparation of rabbit polyclonal antibodies to the enzyme. Antibodies to the Zea mays endosperm enzyme cross-react with the enzyme from Zea mays vegetative tissues and with an enzyme from the liquid endosperm of oak acorns (Quercus sp). In this paper we report a simplified purification procedure adaptable to the preparation of milligram amounts of the enzyme.

Antibodies↗
PubMed1998

Chloroplast DNA recognizes three refugial sources of European oaks and suggests independent eastern and western immigrations to Finland.

Refugial differentiation and routes of postglacial migration are major determinants of the patterns of geographical variation we see in natural populations today. We used patterns of chloroplast DNA (cpDNA) variation to investigate the postglacial colonization history of the European oak species Quercus robur and Q. petraea. By sequencing two cpDNA segments using universal primers, we revealed four polymorphic sites which identify four cytotypes with characteristic geographical distributions. Of these, the principal eastern, central and western cytotypes divide the range into three longitudinal zones, each extending from the south to the north of Europe. This corroborates the idea that the postglacial colonization started from three distinct southerly refugia. The fourth cytotype, restricted to East Anglia, was probably derived from the western type postglacially. As a special problem, we addressed the controversial origin of Q. robur at its northern limits in south-western Finland, where it currently occupies a narrow coastal zone disjunct from the remaining oak range. Using a PCR-RFLP assay that discriminates the eastern cytotype, a contact zone of two cytotypes was identified in the region of the Salpausselkä ridges. This suggests that the marginal northern occurrence was independently colonized both from the east and from the west, across the Baltic Sea.

Chloroplasts↗
PubMed1997

Visualization of the cytoskeleton within the secondary vascular system of hardwood species.

A single fixation technique has been devised to demonstrate localization of alpha-tubulin (for microtubules) and F-actin (for microfilaments) within the secondary vascular system of hardwood trees by indirect immunofluorescence microscopy using butyl-methylmethacrylate-embedded material. Application of this technique to problems of cytomorphogenesis during secondary growth and its versatility are demonstrated with the hardwood species Aesculus hippocastanum L., Salix viminalis L., S. burjatica Nazarov x S. viminalis L., Hedera helix L., Acer platanoides L., Platanus sp., Quercus ilex L. and Liriodendron tulipifera L., and in the softwood Pinus pinea L. The methods employed have considerable scope for advancing knowledge of the role of the cytoskeleton in differentiation within the secondary vascular system of woody species.

Actins↗
PubMed1998

Comparative phylogeography and postglacial colonization routes in Europe.

The Quaternary cold periods in Europe are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in both animals and plants. The phylogeographies of 10 taxa, including mammals (Ursus arctos, Sorex spp., Crocidura suaveolens, Arvicola spp.), amphibians (Triturus spp.), arthropods (Chorthippus parallelus), and plants (Abies alba, Picea abies, Fagus sylvatica, Quercus spp.), were analysed to elucidate general trends across Europe. Only a small degree of congruence was found amongst the phylogeographies of the 10 taxa, but the likely postglacial colonization routes exhibit some similarities. A Brooks parsimony analysis produced an unrooted area phylogram, showing that: (i) the northern regions were colonized generally from the Iberic and Balkanic refugia; and (ii) the Italian lineages were often isolated due to the presence of the Alpine barrier. The comparison of colonization routes highlighted four main suture-zones where lineages from the different refugia meet. Some of the intraspecific genetic distances among lineages indicated a prequaternary divergence that cannot be connected to any particular cold period, but are probably related mainly to the date of arrival of each taxon in the European continent. As a consequence, molecular genetics so far appears to be of limited use in dating Quaternary events.

Animals↗
PubMed2001

The root rot fungus Armillaria mellea introduced into South Africa by early Dutch settlers.

Dead and dying oak (Quercus) and numerous other woody ornamental trees and shrubs showing signs and symptoms of Armillaria root rot were identified in the Company Gardens, Cape Town, South Africa, which were established in the mid-1600s by the Dutch East Indies Trading Company. Nineteen isolates from dying trees or from mushrooms were collected and analysed to identify and characterize the Armillaria sp. responsible for the disease. The AluI digestion of the amplified product of the first intergenic spacer region (IGS-1) of the rRNA operon of 19 isolates from the Company Gardens was identical to that of some of the European isolates of A. mellea s. s. The IGS-1 region and the internal transcribed spacers (ITS) were sequenced for some of the Cape Town isolates. Phylogenetic analyses placed the Cape Town isolates in the European clade of A. mellea, which is distinct from the Asian and North American clades of this species. Identification based on sexual compatibility was conducted using A. mellea tester strains in diploid-haploid pairings, which showed some compatibility between the Cape Town isolates and testers from Europe. Somatic compatibility tests (diploid-diploid pairings) and DNA fingerprinting with multilocus, microsatellite probes indicated that the Cape Town isolates were genetically identical and may have resulted from vegetative (clonal) spread from a single focus in the centre of the original Company Gardens (c. 1652). The colonized area is at least 345 m in diameter. Assuming a linear spread rate underground of 0.3 m/year to 1.6 m/year, the genet (clone) was estimated to be between 108 and 575 years old. These data suggest that A. mellea was introduced into Cape Town from Europe, perhaps on potted plants, such as grapes or citrus, planted in the Company Gardens more than 300 years ago.

Agaricales↗
PubMed2001

Differential success in northwards range expansion between ecotypes of the marble gallwasp Andricus kollari: a tale of two lifecycles.

The Marble gallwasp Andricus kollari has a native range divided into two geographically separated lifecycles. In Eastern Europe and Turkey, the lifecycle involves a sexual generation on Turkey oak, Quercus cerris, while in Iberia and North Africa the sexual generation host is cork oak, Q. suber. Over the last 500 years, A. kollari has expanded its range into northern Europe, following human planting of Q. cerris from Italy and the Balkans. We ask: (i) what is the genetic relationship between eastern and western distributions of Andricus kollari? Can we determine which lifecycle is ancestral, and how long ago they diverged? (ii) To what extent have eastern and western native ranges contributed to northwards range expansion? (iii) Is there any evidence for hybridization between the two life cycle types? We present analyses of allozyme data for 13 polymorphic loci and of sequence variation for a 433 bp fragment of the mitochondrial cytochrome b gene. These show: (i) that four haplotype lineages (one in Spain, two in Hungary/Italy and one in Turkey) diverged more or less simultaneously between 1 and 2 million years ago, suggesting the existence of at least four refuges through recent ice age cycles. Our data cannot resolve which lifecycle type is ancestral. (ii) Populations north of putative refuges are divided into two sets. Populations in south-west France are allied to Spain, while all remaining populations in northern Europe have been colonized from Italy and the Balkans. (iii) The transition from one race to another in south-west France is marked by abrupt transitions in the frequency of refuge-specific private alleles and corresponds closely to the northern limit of the distribution of cork oak. Although hybrids were detected in north-west France, none were detected where the two lifecycles meet in south-western France. The biology of oak gallwasps predicts that any hybrid zone will be narrow, and limited to regions where Q. cerris and Q. suber meet. Our data suggest that eastern and western A. kollari are effectively separate species.

Alleles↗
PubMed2001

Molecular identification of fine roots of trees from the Alps: reliable and fast DNA extraction and PCR-RFLP analyses of plastid DNA.

Fine roots of trees are intensively used as indicators to assess soil alterations, e.g. those owing to atmospheric inputs of acidifying substances, but their identification to species with morphological criteria is difficult. In this study, we established molecular techniques in order to identify fine roots of the 30 most common tree species of the Alps. We developed a protocol for efficient isolation of DNA from fine roots with extraction of DNA in the presence of polyvinylpyrrolidone (PVP) and polyvinylpolypyrrolidone (PVPP). The trnL (UAA) intron of plastid DNA was used as a marker for fine root identification. We amplified and sequenced this intron with plant universal primers. The size of the sequences ranged from 444 to 672 bp. A synoptic key for species identification was designed on the basis of restriction fragment patterns predicted from sequence data. Using the restriction enzyme TaqI as key enzyme, and where necessary HinfI, RsaI and CfoI, 16 taxa, including Picea abies, Larix decidua, Abies alba, and Fagus sylvatica, the dominant tree species of the Alpine region could be identified by agarose gel electrophoresis of restriction fragments. Fourteen taxa could be identified to the genus level, among them Quercus, Salix and Populus species. In a field study, conducted in a 20 x 30 m plot of a mixed forest with five tree species, fine roots of 43 out of 46 samples were identified and their distributions were mapped. These results demonstrate the utility of our DNA extraction method and of the trnL intron for the identification of fine tree roots.

DNA, Plant↗
PubMed1992

An account of the ticks of the northeastern of Spain (Acarina: Ixodidae).

The tick species commonly collected at the Northeast of Spain are reported in this paper. Data on hosts, temperature and humidity requirements, vegetation relationships, altitudinal distribution, and seasonal activity are included. R. sanguineus is commonly collected in areas with Mediterranean vegetation, esteppe, and semi-desertic esteppe, ranging from 190 to 1,000 meters above the sea level. R. sanguineus is related with sparse vegetal areas, and it is absent from areas with dense shrub or forests of every kind; sometimes, small populations may be collected in ecotones between Pinus spp. and esteppe formations. R. pusillus is closely related to areas of Mesomediterranean vegetation, sometimes subordinate to Pinus spp. and Quercus spp. The climate to which the species ally is always of continental type, with a hot and dry summer, and cold winter; although the species is commonly restricted to its main host, Oryctolagus cuniculus, several specimens have been collected from V. vulpes. Our data display the clear affinity of I. ricinus to the Supramediterranean vegetation (Aceri-Quercion faginae), places of Quercetum-Buxetum, as well as the Iberian Oromediterranean vegetation (Pinus sylvestris-Buxus sempervirens). Captures are scarce in forest of Fagus sylvatica, but data suggest that the species may be locally common on such places. Climate for the zones of collection of I. ricinus is Atlantic attenuated, with mild summers and humid winters. D. marginatus is strongly related to the xerophilic vegetation, widely spread through the Mediterranean, Supramediterranean, and hill levels, but does not colonize the true Oromediterranean vegetation. In our captures, the species is commonly collected in pubescent oak formations, but it does not penetrate in true forest associations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Cushing's disease: a new approach to therapy in equine and canine patients.

Forty-one cases of Cushing's Disease affecting both equine and canine patients were treated with an identical mixture of two homeopathically prepared remedies (ACTH 30c and Quercus robur 30c), and the clinical improvements seen in the cases assessed. Homeopathy has been described as a medicine that can only be prescribed on the basis of individual symptoms shown, fitting the remedy to the patient, not the disease. The aim of this study was to define whether a standardised approach, using homeopathically prepared remedies, was a valid system of therapy for this disease, and if so, whether results were repeatable between species. The overall success rate for the therapy was 80% and results were broadly similar between the two species, indicating that homeopathy lends itself to the treatment of Cushing's Disease, and also to both cohort studies and group medicine.

Adrenocorticotropic Hormone↗
PubMed2006

In vitro immunoreactivity towards lectin-rich or viscotoxin-rich mistletoe (Viscum album L.) extracts Iscador applied to healthy individuals.

The aim of the study was to investigate how exposure to mistletoe extracts in vivo may influence cellular immune reactions by peripheral blood mononuclear cells (PBMC). 47 healthy individuals were exposed for twelve weeks either to Iscador Quercus special (IQ; rich in mistletoe lectin [ML]) (n = 16), to Iscador Pinus (IP; poor in ML but rich in viscotoxin) (n = 15), or to placebo (physiological saline) (n = 16). PBMC were isolated before exposure, during exposure in week 4, 8 and 12, as well as 13 weeks after last exposure (week 25) and incubated for 7 days with IQ or IP. Proliferative response and cytokine release were determined (type 1 cytokines: interferon [IFN]-gamma, tumor necrosis factor [TNF]-gamma, type 2 cytokines: interleukin [IL]-5, IL-13, macrophage/ monocyte-cytokines: IL-1, TNFalpha). IP- and IQ incubation of PBMC from non-exposed individuals lead to a significant increase of proliferation and production of all cytokines. There was a significant increase of IQ-induced TNFalpha (but not IL-1) production by PBMC in week 25 in individuals receiv-type 2-cytokines IL-5 and IL-13 significantly decreased during the observation period (p < 0.05 compared to placebo in week 8). These data indicate that IP seems to contain an antigen, which decreases type 2 reactivity. Furthermore, a component present preferentially in IQ seems to activate the production of the monocyte/ macrophage-related cytokine TNFalpha by PBMC. Intriguingly, also in individuals receiving placebo injections immunological alterations were detected during the observation period.

Adult↗
PubMed2006

Nitric oxide involvement in the anti-tumor effect of mistletoe (Viscum album L.) extracts Iscador on human macrophages.

Lectins from different types of mistletoe (Viscum album, VA) have cytotoxic and immunomodulatory properties that may be relevant in the inhibition of tumor growth. The mechanism of this anti-tumoral activity remains unknown, although recent investigations point out the induction of anti-tumoral cytotoxic T cell activation. In this study therapeutically available mistletoe extracts (Iscador) prepared from Quercus (VA-Q), apple (Malus, VA-M) or pine (Pinus, VA-P) were used to investigate their capacity to induce tumor regression through the modulation of another T helper-1 (Th-1)-mediated anti-tumoral activity: the activation of macrophages. Macrophages are essential targets for both pro- or anti-inflammatory drugs and constitute an essential member of the anti-tumoral immune response. Freshly isolated human monocyte-derived macrophages are activated and various VA extracts are directly incorporated to cultures to assay their properties on the inflammatory and/or tumor cytotoxic responses. The data indicate that immunomodulatory activities of VA extracts differ according to their origin. VA-M and VA-P were able to increase anti-tumoral activity of activated human macrophages, with a possible role for nitric oxide in this effect.

Antineoplastic Agents, Phytogenic↗