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At least 847 records · Page 47Linked to original sources
PubMed1998

Pigweed (Amaranthus retroflexus) toxicosis in cattle.

Four of approximately 15 dry cows introduced on a 10-acre fescue-clover-orchard grass-Dallis grass pasture in East Tennessee became recumbent. Clinical findings included depression, muscle tremors, increased heart and respiratory rates, hypocalcemia, hypomagnesemia, hyperkalemia, azotemia, and elevated creatinine phosphokinase. Three cows recovered; 1 died. Differential diagnoses considered were hypocalcemia, hypomagnesemia, rabies and toxicoses from Amaranthus retroflexus (pigweed), Quercus spp (oak), Cassia spp (senna) oxalate (Aspergillus niger or flavus), mycotoxicosis, lead, arsenic or insecticides. Pigweed toxicosis was confirmed based on clinical and postmortem findings, partially ingested pigweed in the pasture, and ruling out other possible causes. Several factors probably contributed to this incident: since the cattle were newly introduced to the pasture, the cattle may have been attracted to the pigweed in the new pasture and became addicted to it; their rumen microflora had little time to acclimate to the pigweed; and dry weather produced poor forage quality thus forcing the cows to eat the pigweed.

Animals↗
PubMed1998

Comparison of the effects of various clinically applied mistletoe preparations on peripheral blood leukocytes.

The aim of the present study was to compare the biological effects of 12 different clinically applied mistletoe preparations (I, II, III and IV) from the host trees "pinus" (P), "malus" (M), "abies" (A) and "quercus" (Q) on human leukocytes. When the preparations I-P, II-P, III-P and IV-A were added to the whole blood cell cultures of 37 cancer patients (breast cancer, n = 22, colorectal cancer, n = 15) and 34 healthy controls, a significant induction of the cytokines IL-1-beta, IL-2, IL-6, IL-10 and TNF-alpha was found with preparation I-P. A significant induction of IL-1-beta and TNF-alpha was obtained with the preparations II-P and III-P as compared to the nonstimulated control cultures. Induction of IFN-gamma was not found with any preparation. Cytokine induction was comparable in the blood cell cultures of the tumor patients and the healthy controls. When the clinical preparations I-P, I-M, I-Q, II-P, II-M, II-A, III-P, III-M, III-A and IV-P, IV-M, IV-A were tested in cultures of peripheral blood mononuclear cells from 5 healthy donors, differences in the induction of cytokine production and apoptosis were seen after addition of the mistletoe preparations from different host trees. Increased levels of IL-1-beta were found after addition of the preparations I-P and I-M, increased levels of TNF-alpha were measured after addition of preparations I-P and III-A. Induction of apoptosis was most evident with the preparations I-M, I-Q, III-M and IV-A. Neither cytokine induction nor apoptosis could be correlated to the amount of lectins found in the preparations. Stimulation of separated CD4(+)-, CD8(+)- and CD14(+)-cells from 5 healthy donors with the above noted preparations revealed an induction of IL-1-beta and TNF-alpha production by the preparations I-P, I-M and I-Q mainly in monocytes and to a minimal extent in lymphocytes. Also apoptosis was seen mainly in CD14(+)-monocytes. From these results it is concluded that both, apoptosis and cytokine production are induced differentially in leukocyte cultures by clinically applied mistletoe preparations. However, there is no correlation between the biological effects and the lectin content of the various preparations and none of them were comparable with respect to the extent of these effects. Therefore, it may be expected that clinical studies with different preparations are not comparable either.

Adult↗
PubMedDate not supplied

Explorative kinetic study on the thermal degradation of five wood species for applications in the archaeological field.

Differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) were performed on wood samples of different essences (fir, chestnut, poplar, linden and oak) before consolidation. A kinetic analysis was applied on the two-steps decomposition processes occurring in all wood samples using either the multiheating rates Kissinger equation and the isoconversional Ozawa-Flynn-Wall method that enables the variation of activation energy to be determined as a function of the degree of reaction. Taking into account both decomposition temperature and activation energy for the first degradation step oak seems to be the less stable sample. The comparison of DSC curves performed in air with those in oxygen enables to consider the role of the partial pressure of oxygen in the mechanisms of both decompositions.

Abies↗
PubMedDate not supplied

Isolation of high-quality RNA from polyphenol-, polysaccharide- and lipid-rich seeds.

Seed polyphenols, polysaccharides and lipids often interfere with or degrade RNA, restricting its yield and quality. Existing RNA isolation methods specifically alleviate one or two of these challenges, but are usually designed for a single species rather than for a broad biodiversity. Many protocols also do not eliminate chromosomal DNA, which causes false positives in gene expression studies. The method reported here addresses all of the above challenges. The concentration of the phenol blocker polyvinylpyrrolidone in the extraction buffer was optimised for use on a broader range of species. DNase I was added to eliminate chromosomal DNA and the timing of this step was optimised. Lipids were removed by centrifugation. Polysaccharides and proteins, including excess DNase I, were separated from RNA during ethanol precipitation of nucleic acids. In seeds of five plant species from four taxonomically distant families, significant amounts of RNA were isolated in less than half the time typically required by previously reported methods. Colorimetric tests showed that the isolated RNA was free from interfering contaminants. In addition, reverse transcription-PCR confirmed that the isolated RNA was of appropriate quality and integrity for gene expression studies.

Arabidopsis↗
PubMed2006

Variation in the holm oak leaf proteome at different plant developmental stages, between provenances and in response to drought stress.

Major proteins of the holm oak leaf proteome have been previously identified using a combination of 2-DE, MS analysis and BLAST similarity search (Jorge et al., Proteomics 2005, 5, 222-234). That study, conducted with field samples from mature trees, revealed the existence of a great variability in the 2-DE protein map, with qualitative as well as quantitative changes, both analytical and biological. A similar study has been carried out with 2-year-old seedlings to analyze and study: (i) changes in the 2-DE protein profile at different tree developmental stages; (ii) the 2-DE protein map variability between three different Spanish provenances; and (iii) variations in the 2-DE protein profile in response to drought stress. Although the protein profile of leaves from seedlings and mature trees was fairly similar, the biological variance found was lower in the former. In the present study, new proteins have been identified. At least four different protein spots differentiated Spanish provenances, two of them identified as an ATP synthase alpha chain, and a 2,3-bisphosphoglycerate-independent phosphoglycerate mutase. Fourteen different protein spots were qualitatively variable between well-watered and drought-stressed seedlings, with some of them corresponding to enzymes of carbohydrate and protein metabolism. Data presented indicated the mobilization of storage proteins and carbohydrates, as well as photosynthesis inhibition under drought conditions.

Dehydration↗
PubMed2002

Laboratory evaluation of two novel strategies to control first-instar gypsy moth larvae with spinosad applied to tree trunks.

Two strategies for controlling first-instar larvae of gypsy moth (Lymantria dispar (L)), insecticidal bait and contact insecticide applied directly to the tree trunk, were evaluated in the laboratory. Spinosad was selected as a candidate natural-product insecticide that is active both by contact and ingestion. Incorporated into artificial diet-based bait, spinosad was toxic to neonate larvae with a minimal 10-s feeding period, with an LC50 value of 20 (15-26, 95% confidence interval) mg liter-1. It was significant that neonate larvae did not discriminate between spinosad-treated and control diet. Efficacy of diet-based bait in the laboratory, however, was significantly impacted by previous exposure to diet; fed larvae did not stop at the bait and did not incur mortality, as compared to unfed larvae. Oak bark was a suitable substrate from which neonate larvae could contact spinosad residues. Spinosad applied directly to oak bark resulted in significant mortality after 1- and 4-min crawling contact exposure times (LC50 = 24 [20-29, 95% CI] and 8.7 [6.9-11, 95% CI] mg liter-1, respectively) and contact activity persisted for 2 weeks. While contact activity was more potent on glass surfaces than on oak bark, the LC50 values differed only by factors of 2.4 and 3.6, for 1- and 4-min exposures respectively.

Animals↗
PubMed2005

Assessing the pathogenic effect of Fusarium, Geosmithia and Ophiostoma fungi from broad-leaved trees.

Phytopathogenic effect of Geosmithia pallida, G. langdonii, Ophiostoma grandicarpum, O. querci, two isolates of O. piceae, and two isolates of Fusarium solani was compared using plant growth test (stem and root length of garden cress plants seeded on mycelium-covered potato carrot agar); Ophiostoma spp. and F. solani were isolated from oak, Geosmithia spp. from galleries of Scolytus intricatus on beech. All fungi inhibited more the root elongation than that of stems. F. solani led to plant collapse after briefly stimulating the growth of stem and in one case also root. G. langdonii inhibited stem and root growth to 20% and led to plant collapse. G. pallida inhibited root growth to 25% whereas stem growth was almost unimpaired. Ophiostoma spp. reduced stem growth to approximately 60-80% and root growth to 25-60%. O. piceae and O. querci caused plant collapse after 15-20 d.

Animals↗
PubMed2006

Determination of volatile oak compounds in aged wines by multiple headspace solid-phase microextraction and gas chromatography-mass spectrometry (MHS-SPME-GC-MS).

Multiple headspace solid-phase microextraction (MHS-SPME) with gas chromatography-mass spectrometry is proposed for quantification of nine volatile oak compounds in aged wines. These compounds are formed and extracted by wine when it is matured in oak barrels and are responsible for particular organoleptic properties and the high quality of these wines. Some important variables of the extraction process, for example volume of sample and extraction time, were studied. Extraction of 50 microL wine was performed with a divinylbenzene-Carboxen-polydimethylsiloxane fibre at 55 degrees C for 60 min. For calibration the same conditions were used, except that the wine was substituted by 50 microL of a standard solution in synthetic wine. The linearity, detection limits, and repeatability of the method were determined by use of standard solutions in synthetic wine. Detection limits were between 0.01 and 10 microg L(-1) (for eugenol and furfural, respectively) and repeatability, expressed as relative standard deviation, was from 2 to 6%. The method was used to analyse six red wines and the concentrations obtained were statistically compared with those obtained by the standard addition method for the same wines.

Gas Chromatography-Mass Spectrometry↗
PubMed2006

Seasonal dynamics of microbial community composition and function in oak canopy and open grassland soils.

Soil microbial communities are closely associated with aboveground plant communities, with multiple potential drivers of this relationship. Plants can affect available soil carbon, temperature, and water content, which each have the potential to affect microbial community composition and function. These same variables change seasonally, and thus plant control on microbial community composition may be modulated or overshadowed by annual climatic patterns. We examined microbial community composition, C cycling processes, and environmental data in California annual grassland soils from beneath oak canopies and in open grassland areas to distinguish factors controlling microbial community composition and function seasonally and in association with the two plant overstory communities. Every 3 months for up to 2 years, we monitored microbial community composition using phospholipid fatty acid (PLFA) analysis, microbial biomass, respiration rates, microbial enzyme activities, and the activity of microbial groups using isotope labeling of PLFA biomarkers (13C-PLFA). Distinct microbial communities were associated with oak canopy soils and open grassland soils and microbial communities displayed seasonal patterns from year to year. The effects of plant species and seasonal climate on microbial community composition were similar in magnitude. In this Mediterranean ecosystem, plant control of microbial community composition was primarily due to effects on soil water content, whereas the changes in microbial community composition seasonally appeared to be due, in large part, to soil temperature. Available soil carbon was not a significant control on microbial community composition. Microbial community composition (PLFA) and 13C-PLFA ordination values were strongly related to intra-annual variability in soil enzyme activities and soil respiration, but microbial biomass was not. In this Mediterranean climate, soil microclimate appeared to be the master variable controlling microbial community composition and function.

Bacteria↗
PubMed2005

Myxobacterial biodiversity in an established oak-hickory forest and a savanna restoration site.

The purpose of this study was to establish the myxobacterial biodiversity of an established oak-hickory forest and a savanna restoration site that has been cut and subsequently burned on four occasions between 1993 and 1998 in an attempt to restore the land to the native savanna ecosystem. Soil and bark samples were processed through standard methods specifically for myxobacteria and numbers and types of species were recorded for both locations. Species were identified through morphology of fruiting bodies, SDS-PAGE of whole cell protein profiles, and 16S rRNA gene sequences. Statistical analyses were employed and suggested that significantly greater numbers and types of myxobacteria are present on the bark of the trees in the established oak-hickory forest than the bark of trees in the savanna restoration site, while little difference in numbers and types of species were observed between the soil samples of the two locations.

Base Sequence↗
PubMed2006

Transcriptional changes in two types of pre-mycorrhizal roots and in ectomycorrhizas of oak microcuttings inoculated with Piloderma croceum.

The formation of the ectomycorrhiza implies an alteration in gene expression of both the plant and fungal partners, a process which starts before the formation of any symbiotic interface. However, little is known on the regulation pattern occurring in different parts of the root system. Our experimental system consisting of a micropropagated oak with a hierarchical root system was shown to exhibit symbiosis functional traits prior to any mycorrhizal tissue differentiation after the inoculation with the basidiomycete Piloderma croceum. Using a cDNA array, the plant gene regulation was analyzed in the pre-mycorrhizal phase. Seventy-five transcripts showed differential expression in pre-mycorrhizal lateral and principal roots, and both root types exhibited different sets of responsive genes. For transcripts selected according to a statistical analysis, the alteration in gene expression was confirmed by RT-PCR and quantitative real-time PCR. Genes regulated in pre-mycorrhizal lateral roots displayed an almost identical expression in mycorrhizas. In contrast, genes regulated in pre-mycorrhizal principal roots were often regulated differently in ectomycorrhizas. Down-regulation affected most of the regulated genes involved in metabolism, whereas most of the regulated genes related to cell rescue functions, water regulation and defence response were up-regulated. Regulation of such genes could explain the increase of global resistance observed in mycorrhizal plants.

Basidiomycota↗
PubMed2003

Controls on mass loss and nitrogen dynamics of oak leaf litter along an urban-rural land-use gradient.

Using reciprocal leaf litter transplants, we investigated the effects of contrasting environments (urban vs. rural) and intraspecific variations in oak leaf litter quality on mass loss rates and nitrogen (N) dynamics along an urban-rural gradient in the New York City metropolitan area. Differences in earthworm abundances and temperature had previously been documented in the stands along this gradient. Red oak leaf litter was collected and returned to its original source stand as native litter to measure decay rates along the gradient. To separate site effects from litter quality effects on decay, reciprocal transplants of litter were also made between stands at the extremes of the environmental gradient (urban and rural stands). Land-use had no effect on mass loss and N dynamics of native litter by the end of the 22-month incubation period. The lack of differences in native litter suggests the factors affecting decay were similar across the stands in this study. However, in the transplant study both environment and litter type strongly affected decay of oak leaf litter. On average urban and rural litter decomposed faster over the incubation period in urban than in rural stands (P=0.016 and P=0.001, respectively, repeated measures ANOVA). Differences in mass loss between urban and rural stands resulted in rural environments having less mass remaining than urban environments at the end of the incubation period (25.6 and 46.2% for urban and rural sites, respectively). Likewise, less N remained in leaf residue in urban sites (71.3%) compared to that in rural sites (115.1%). Litter type also affected mass loss rates during the 22-month incubation period. On average rural litter mass loss rates were faster than urban litter rates in both urban and rural stands (P=0.030 and P=0.026, respectively, repeated measures ANOVA). By the end of the incubation period, rural litter exhibited 43 and 20% greater mass loss and retained 44 and 5% less N than urban litter decomposing in the same urban and rural sites, respectively. These results suggest that different factors were controlling mass loss and N release rates along this urban-rural gradient. In urban stands, exotic earthworms and warmer temperatures may be compensating for what would otherwise be slowly decaying leaf litter because of its lower quality. Likewise, the lower quality litter produced in the urban stands may be decreasing the net release of N from litter despite higher temperatures and earthworm activity. Even though native litter decay rates were similar, the differential importance of the factors affecting decay along this gradient could alter the response of these forests to disturbance and variations in climate.

Animals↗
PubMed2003

Microbial community utilization of recalcitrant and simple carbon compounds: impact of oak-woodland plant communities.

Little is known about how the structure of microbial communities impacts carbon cycling or how soil microbial community composition mediates plant effects on C-decomposition processes. We examined the degradation of four (13)C-labeled compounds (starch, xylose, vanillin, and pine litter), quantified rates of associated enzyme activities, and identified microbial groups utilizing the (13)C-labeled substrates in soils under oaks and in adjacent open grasslands. By quantifying increases in non-(13)C-labeled carbon in microbial biomarkers, we were also able to identify functional groups responsible for the metabolism of indigenous soil organic matter. Although microbial community composition differed between oak and grassland soils, the microbial groups responsible for starch, xylose, and vanillin degradation, as defined by (13)C-PLFA, did not differ significantly between oak and grassland soils. Microbial groups responsible for pine litter and SOM-C degradation did differ between the two soils. Enhanced degradation of SOM resulting from substrate addition (priming) was greater in grassland soils, particularly in response to pine litter addition; under these conditions, fungal and Gram+ biomarkers showed more incorporation of SOM-C than did Gram- biomarkers. In contrast, the oak soil microbial community primarily incorporated C from the added substrates. More (13)C (from both simple and recalcitrant sources) was incorporated into the Gram- biomarkers than Gram+ biomarkers despite the fact that the Gram+ group generally comprised a greater portion of the bacterial biomass than did markers for the Gram- group. These experiments begin to identify components of the soil microbial community responsible for decomposition of different types of C-substrates. The results demonstrate that the presence of distinctly different plant communities did not alter the microbial community profile responsible for decomposition of relatively labile C-substrates but did alter the profiles of microbial communities responsible for decomposition of the more recalcitrant substrates, pine litter and indigenous soil organic matter.

Benzaldehydes↗