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At least 307 records · Page 17Linked to original sources
PubMed1997

Nutrient fluxes in splanchnic tissue of dairy cows: influence of grass quality.

A crossover design was used to investigate the effects of high (450 kg of N/ha) or low (150 kg of N/ha) N fertilization of ryegrass on fermentation and nutrient fluxes in splanchnic tissue of dairy cows fed those grasses. Grass that was fertilized with the high amount of N contained more N and less sugar than did grass that was fertilized with less N. In rumen fluid, the concentration of NH3 N was lower for ryegrass that was fertilized with the low amount of N. The NH3 release by portal-drained viscera and urea synthesis in the liver were higher for cows fed ryegrass that was fertilized with the high amount of N. The concentration of NH3 N in rumen fluid, NH3 N release in portal-drained viscera, urea synthesis in the liver, urea release from the liver, and urea concentrations in milk were highly correlated. The release of acetate and propionate in portal-drained viscera was similar for both grasses and was well correlated with the proportion of volatile fatty acids in rumen fluid. The proportion of butyrate in rumen fluid was closely correlated with the release of butyrate and beta-hydroxybutyrate in portal-drained viscera. Glucose synthesis in the liver indicated gluconeogenesis from amino acids, which corresponded well with urea synthesis in the liver. For the grass fertilized with more N, availability of energy sources for rumen microbes was low, and, therefore, cows did not use the N in that grass efficiently.

3-Hydroxybutyric Acid↗
PubMed2000

A human monoclonal IgE antibody defines a highly allergenic fragment of the major timothy grass pollen allergen, Phl p 5: molecular, immunological, and structural characterization of the epitope-containing domain.

Almost 90% of grass pollen-allergic patients are sensitized against group 5 grass pollen allergens. We isolated a monoclonal human IgE Fab out of a combinatorial library prepared from lymphocytes of a grass pollen-allergic patient and studied its interaction with group 5 allergens. The IgE Fab cross-reacted with group 5A isoallergens from several grass and corn species. By allergen gene fragmentation we mapped the binding site of the IgE Fab to a 11.2-kDa N-terminal fragment of the major timothy grass pollen allergen Phl p 5A. The IgE Fab-defined Phl p 5A fragment was expressed in Escherichia coli and purified to homogeneity. Circular dichroism analysis revealed that the rPhl p 5A domain, as well as complete rPhl p 5A, assumed a folded conformation consisting predominantly of an alpha helical secondary structure, and exhibited a remarkable refolding capacity. It reacted with serum IgE from 76% of grass pollen-allergic patients and revealed an extremely high allergenic activity in basophil histamine release as well as skin test experiments. Thus, the rPhl p 5A domain represents an important allergen domain containing several IgE epitopes in a configuration optimal for efficient effector cell activation. We suggest the rPhl p 5A fragment and the corresponding IgE Fab as paradigmatic tools to explore the structural requirements for highly efficient effector cell activation and, perhaps later, for the development of generally applicable allergen-specific therapy strategies.

Allergens↗
PubMed2004

Molecular characterization of polygalacturonases as grass pollen-specific marker allergens: expulsion from pollen via submicronic respirable particles.

Grass pollen belong to the most important allergen sources involved in the elicitation of allergic asthma. We have isolated cDNAs coding for Bermuda grass (Cynodon dactylon) and timothy grass (Phleum pratense) pollen allergens, belonging to a family of pectin-degrading enzymes (i.e., polygalacturonases). The corresponding allergens, termed Cyn d 13 and Phl p 13, represent glycoproteins of approximately 42 kDa and isoelectric points of 7.5. rPhl p 13 was expressed in Escherichia coli and purified to homogeneity. Immunogold electron microscopy using rabbit anti-rPhl p 13 Abs demonstrated that in dry pollen group 13, allergens represent primarily intracellular proteins, whereas exposure of pollen to rainwater caused a massive release of cytoplasmic material containing submicronic particles of respirable size, which were coated with group 13 allergens. The latter may explain respiratory sensitization to group 13 allergens and represents a possible pathomechanism in the induction of asthma attacks after heavy rainfalls. rPhl p 13 was recognized by 36% of grass pollen allergic patients, showed IgE binding capacity comparable to natural Phl p 13, and induced specific and dose-dependent basophil histamine release. Epitope mapping studies localized major IgE epitopes to the C terminus of the molecule outside the highly conserved functional polygalacturonase domains. The latter result explains why rPhl p 13 contains grass pollen-specific IgE epitopes and may be used to diagnose genuine sensitization to grass pollen. Our finding that rabbit anti-rPhl p 13 Abs blocked patients' IgE binding to the allergen suggests that rPhl p 13 may be used for immunotherapy of sensitized patients.

Allergens↗
PubMed2002

[Distribution characteristics and chemical pattern of cadmium in grasses planted in the cadmium contaminated soil].

In this paper, the distribution and chemical pattern of Cd in the grasses planted in Cd contaminated soil in western suburb of Shenyang were analyzed. The results showed that Cd was mainly distributed in the grass roots, and characteristics of Cd distribution in various grasses were different. Some grasses had resisting ability against Cd, some had strong capability of bio-accumulation for Cd. Results of different grasses extracted by different solvents showed that acid-soluble Cd in grasses was about 63.3% of total, and water-soluble and organic Cd were little, accounting for 0.7% and 0.4% of total respectively. Acid-soluble Cd was more active than the others during the transformation in the soil-plant system, while water-soluble Cd had certain regularity with the change of time and temperature, and organic Cd became more active with the increase of solvent polarity.

Cadmium↗
PubMed2002

Evaluation of urinalysis as an aid in the diagnosis of equine grass sickness.

To determine whether urinalysis can aid the diagnosis of equine grass sickness, samples of urine from 15 horses with acute grass sickness, eight horses with subacute grass sickness, 17 co-grazing horses and 17 stabled control horses were analysed. The samples from all of the horses with grass sickness had a significantly higher specific gravity, higher protein and creatinine concentrations and a significantly lower pH; the samples from the horses with acute grass sickness also had significantly higher glucose concentrations. These differences may support a diagnosis of grass sickness but they are not pathognomonic for the disease.

Acid-Base Equilibrium↗
PubMed2003

Grassed swales for stormwater pollution control during rain and snowmelt.

The retention of suspended solids, particles and heavy metals in different grassed swales during rain events and snowmelt is discussed. The experimental results derived from investigations performed in existing grassed swales in the Luleå region, Northern Sweden. During high pollutant loading rates, grassed swales retain significant amounts of pollutants, mainly due to sedimentation of particulate matter. Low to moderate removal efficiencies could be expected for heavy metals, especially metals in solution (i.e. the dissolved phase). When grassed swales receive urban runoff with low pollutant concentrations, they may release rather than retain pollutants. Swales are important snow deposit areas in the city and particle bound pollutants do to a large extent remain in the swale after snowmelt. However, dissolved pollutants (i.e. dissolved heavy metals) are likely to escape the swale with the melt water. Grassed swales may be regarded as facilities that even out the peaks in pollutant loads without being capable of producing consistent high removal rates. This suggests that swales should be considered as primary treatment devices. Possible design parameters for grassed swales are mean hydraulic detention time, surface loading rate or specific swale area.

Biodegradation, Environmental↗
PubMed1993

Increased concentrations of omega-3 fatty acids in milk and platelet rich plasma of grass-fed cows.

Epidemiological data indicate that omega-3 fatty acids protect from cardiovascular diseases and hyperlipidemia. Cold water fish is the major recognized source of omega-3 fatty acids but fish is not a staple food in many countries. Since terrestrial green plants may also represent a source of omega-3 fatty acids we tested the hypothesis that platelet rich plasma and milk from cows feeding exclusively on green grass contains more omega-3 fatty acids than milk from cows fed conserved grass. The relative concentrations of linolenic acid (18:3) and eicosapentaenoic acid (20:5) and the ratio of eicosapentaenoic acid to arachidonic acid (20:4) which is critical for the formation of omega-3 derived eicosanoids were significantly higher in milk from grass fed cows. Similar changes were seen in the fatty acid composition of platelets. Half a liter of milk from grass-fed cows provides approximately 191 mg 18:3 and 14 mg 20:5. In this regard milk from grass fed cows may be nutritionally superior to milk from cows eating conserved grass.

Analysis of Variance↗
PubMed1977

Comparison of the daily endogenous faecal magnesium excretion from sheep eating grass with high sodium or high potassium concentrations.

Metabolism trials were conducted with two sheep to determine the daily endogenous faecal magnesium excretion and the true magnesium availability of grass which had either a high potassium or a high sodium content. The experiment was conducted as a simple cross-over design and the isotope dilution technique using 28Mg was employed. The sheep ate sodium fertilised grass containing 0-73 per cent Na and 1-55 per cent K and potassium fertilised grass containing 0-15 per cent Na and 3-12 per cent K in the dry matter. The daily endogenous faecal magnesium excretion was not found to be significantly different for each sheep on both grasses; this excretion was approximately 13 per cent of the total faecal magnesium output. The true availability of magnesium was greater in the sodium fertilised grass than in the potassium fertilised grass. It was concluded that the daily endogenous faecal magnesium excretion was not affected by altering the herbage levels of sodium and potassium.

Animal Feed↗
PubMed2002

New, quick tests for herbicide resistance in black-grass (Alopecurus myosuroides Huds) based on increased glutathione S-transferase activity and abundance.

Black-grass (Alopecurus myosuroides Huds) is a major grass weed in winter cereals in Europe. It reduces yields and can act as a secondary host for a range of diseases. Herbicide resistance in this species was first detected in the UK in the early 1980s, and has now been reported in thirty counties. To successfully manage herbicide resistance it is vital that suspect populations are tested so that appropriate action can be taken. Ideally, a test will be quick, cheap and easy to use. Furthermore, it should provide an unequivocal result before post-emergence herbicides are to be applied, allowing alternative strategies to be adopted where necessary. This paper reports the development of new tests for herbicide resistance based on our observation that the resistant black-grass biotype Peldon contains approximately double the activity of the enzyme glutathione S-transferase (GST) compared with susceptible biotypes. Data are presented on the production of a monoclonal antiserum to a novel 30 kDa GST polypeptide purified from the biotype Peldon. An ELISA using this antiserum is described and the utility of this assay to detect resistant black-grass biotypes in plants grown under glass and in the field is presented. In addition, a microtitre assay for GST activity is described, which allows the rapid assessment of GST activities of plants. Both abundance and activity of GSTs are discussed as markers for herbicide resistance in black-grass.

Drug Resistance↗
PubMed1993

Structural alterations of the chloroplast genome found in grasses are not common in monocots.

The distribution of structural rearrangements of the chloroplast genome found in grass cpDNA in comparison to that of tobacco was systematically checked in the cpDNAs of representative monocots. The physical map of lily cpDNA, which shares a key position in the diversity of monocotyledonous plants, was constructed to assess whether three inversions found in grass cpDNA are common in monocots. Specific probes for the detection of (1) intron loss in the rpoC1 gene, (2) insertional sequence gain in rpoC2, (3) deletion of ORF2280 in the inverted repeats, (4) non-reciprocal translocation of rpl23, and (5) rearrangements of ORF512, were hybridized to cpDNAs of lily, onion, spiderwort, two turf grasses, and wheat. The existence of intervening sequences in the rpoC1 and rpoC2 genes was also confirmed by PCR analysis. All markers used in the study revealed that structural rearrangements of the chloroplast genome were restricted to grasses, indicating that drastic structural alterations of the chloroplast genome had occurred in the ancestor(s) of grasses. These results also suggest that structural analysis of the chloroplast genome is applicable to the phylogenetic reconstruction of related plants.

Base Sequence↗
PubMed1984

The regulatory peptide system of the large bowel in equine grass sickness.

In recent years, distinct changes in regulatory peptides have been found in a number of gastrointestinal diseases. Grass sickness is a fatal disease of horses for which the etiology has yet to be fully ascertained. In this study, the peptide-containing nerves and ganglionic and mucosal endocrine cells of the ileum, colon and rectum were investigated in horses with sub-acute or chronic grass sickness and compared with normal controls using immunocytochemistry, at both the light and electron microscopical levels, and radioimmunoassay. A substantial loss of both peptide-containing cells and nerves was found in all of the sick horses, particularly in the ileum. Electron microscopy revealed marked degeneration of nerves in the gut wall. Fibers containing granules immunostained for substance P or VIP, using the immunogold staining technique, underwent extensive degranulation in grass sickness, with the formation of multiple vacuoles. Radioimmunoassay of peptide content also showed that the most drastic changes occurred in the ileum. For example, VIP content was significantly reduced from 109 +/- 19.8 (mean +/- SEM) pmoles/g in controls to 6.8 +/- 1.4 pmoles/g in grass sickness (p less than 0.001) and substance P from 65.9 +/- 8.1 to 31.3 +/- 9.5 (p less than 0.02). These results may have applications in the diagnosis and treatment of grass sickness.

Animals↗
PubMed2006

Tall fescue genomic SSR markers: development and transferability across multiple grass species.

Simple sequence repeat (SSR) markers are highly informative and widely used for genetic and breeding studies. Currently, a very limited number of SSR markers are available for tall fescue (Festuca arundinacea Schreb.) and other forage grass species. A tall fescue genomic library enriched in (GA/CT)( n ) repeats was used to develop primer pairs (PPs) flanking SSRs and assess PP functionality across different forage, cereal, and turf grass species. A total of 511 PPs were developed and assessed for their utility in six different grass species. The parents and a subset of a tall fescue mapping population were used to select PPs for mapping in tall fescue. Survey results revealed that 48% (in rice) to 66% (in tall fescue) of the PPs produced clean SSR-type amplification products in different grass species. Polymorphism rates were higher in tall fescue (68%) compared to other species (46% ryegrass, 39% wheat, and 34% rice). A set of 194 SSR loci (38%) were identified which amplified across all six species. Loci segregating in the tall fescue mapping population were grouped as loci segregating from the female parent (HD28-56, 37%), the male parent (R43-64, 37%), and both parents (26%). Three percent of the loci that were polymorphic between parents were monomorphic in the pseudo F1 mapping population and the remaining loci segregated. Sequencing of amplified products obtained from PP NFFAG428 revealed a very high level of sequence similarity among the grass species under study. Our results are the first report of genomic SSR marker development from tall fescue and they demonstrate the usefulness of these SSRs for genetic linkage mapping in tall fescue and cross-species amplification.

Base Sequence↗
PubMed2005

Mapping and modeling the biogeochemical cycling of turf grasses in the United States.

Turf grasses are ubiquitous in the urban landscape of the United States and are often associated with various types of environmental impacts, especially on water resources, yet there have been limited efforts to quantify their total surface and ecosystem functioning, such as their total impact on the continental water budget and potential net ecosystem exchange (NEE). In this study, relating turf grass area to an estimate of fractional impervious surface area, it was calculated that potentially 163,800 km2 (+/- 35,850 km2) of land are cultivated with turf grasses in the continental United States, an area three times larger than that of any irrigated crop. Using the Biome-BGC ecosystem process model, the growth of warm-season and cool-season turf grasses was modeled at a number of sites across the 48 conterminous states under different management scenarios, simulating potential carbon and water fluxes as if the entire turf surface was to be managed like a well-maintained lawn. The results indicate that well-watered and fertilized turf grasses act as a carbon sink. The potential NEE that could derive from the total surface potentially under turf (up to 17 Tg C/yr with the simulated scenarios) would require up to 695 to 900 liters of water per person per day, depending on the modeled water irrigation practices, suggesting that outdoor water conservation practices such as xeriscaping and irrigation with recycled waste-water may need to be extended as many municipalities continue to face increasing pressures on freshwater.

Carbon↗
PubMed2005

Immunobiology of grass pollen allergens.

Among pollen allergens, grass pollen allergens are some of the most frequent contributors to allergic symptoms. Substantial progress has been made since the 1960s in the identification and characterization of the grass allergens. Members of this group belong to the Poaceae family, and have been classified into 13 distinct groups based on their structure, and their biological and immunologic properties. The major contributors to allergy and, hence, most studied among the grass allergens, are those belonging to groups 1 and 5. This review is focused on the structure and immunobiology of the grass allergens and highlights how recent advances in the field have contributed to superior diagnosis and immunotherapy for allergy to grass pollens.

Allergens↗
PubMed1983

IgG specific antibodies to rye grass and ragweed pollen antigens in the tear secretions of patients with vernal conjunctivitis.

We studied the tears of 30 patients (25 males and five females, ranging in age from 8 to 34 years) with vernal conjunctivitis for pollen-specific IgG antibodies to rye grass and ragweed antigen E by an enzyme-linked immunosorbent assay (ELISA). Eighteen of 30 (60%) and 20 of 30 (67%) patients with vernal conjunctivitis had significant levels (more than 2 S.D. from the mean of control tears) of IgG antibodies in their tear secretions to rye grass (geometric mean = 68.7 ELISA units) and ragweed antigen E (geometric mean = 50 ELISA units), respectively. In contrast, the control groups (eight atopic individuals, four with seasonal rhinitis, and 12 with allergic conjunctivitis) had low amounts of specific IgG antibodies to these two pollen antigens in their tears. Total IgG and IgM were also increased in the tears of patients with vernal conjunctivitis. To evaluate whether these immunoglobulins and specific IgG antibodies were locally produced by the conjunctival tissues, we used transferrin as a marker for the leakage of plasma proteins into tears. We found that the specific IgG antibodies to rye grass or ragweed antigen E, or both, in the tears were locally produced by the conjunctival tissues. The local production ranged from 20% to 99.9%. Of 17 patients with vernal conjunctivitis and undetectable pollen-specific IgE antibodies in their tears, 14 (82.4%) had tear specific IgG antibodies to rye grass or ragweed antigen E or both, whereas of those with measurable tear IgE antibodies, only nine of 13 (69%) had tear IgG antibodies to rye grass or antigen E or both. These results suggested that both IgE- and IgG-mediated immune mechanisms may be important in the pathogenesis of vernal conjunctivitis.

Adolescent↗
PubMed1994

Seasonal variations in the transfer of 137Cs and 40K to pasture grass and its ingestion by grazing animals.

Samples of grass and sheep faeces were taken monthly over a 12-month period from three pasture sites. Biomass, 137Cs and 40K were measured. The activity concentration of these two radionuclides in grass was influenced by season and soil type. The seasonal patterns of 137Cs and 40K transfer to grass were inversely related, but evidence is presented which suggests that soil contamination of grass samples contributed to the 137Cs and 40K activity concentrations of the grass and augmented the difference between their patterns of transfer. This was influenced by season, climate and farm management. A parallel seasonality was identified in the 137Cs activity concentration of the faeces of sheep grazing these pastures. This was not observed for 40K in sheep faeces.

Animals↗
PubMed1994

Assessment of the role of soil adhesion in the transfer of 137Cs and 40K to pasture grass.

137Cs and 40K were analyzed in pasture grass and soils throughout a 12-month period. The titanium content of the samples was determined as a marker of soil contamination of the grass samples. The 137Cs activity concentration in the grass was closely correlated with titanium and both increase in the winter months suggesting that increased soil contamination of grass is responsible for the increased 137Cs activity concentration observed at this time. The method greatly overestimates the contribution made by soil to the 137Cs activity concentrations of the grass samples and the results are highly variable. Some problems associated with the method are discussed and it is proposed that this method is unreliable.

Adhesiveness↗
PubMed1988

Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. II. Comparison between parameters assessing the efficacy of immunotherapy.

Specific immunotherapy is effective in alleviating symptoms in grass pollen-induced rhinitis, but there are no clear data demonstrating a correlation between symptom-medication scores and objective parameters. Twenty-five patients taking part in a double-blind, placebo-controlled immunotherapy with mixed grass pollen-formalinized allergoids were studied. All patients had the same investigations. Symptom-medication scores were significantly (p less than 0.005, Mann-Whitney U test) reduced in the treated group by comparison to the placebo-treated patients. Nasal challenges performed with threefold increasing numbers of orchard grass-pollen grains demonstrated that patients treated with allergoid tolerated a significantly (p less than 0.005, Wilcoxon W test) greater number of grains after treatment, whereas there was no mean difference in the placebo-treated patients. There was a significant (p less than 0.005, Spearman rank-correlation) correlation between nasal challenges and symptom scores during the season. The skin prick test end point was significantly (p less than 0.001, Wilcoxon W test) reduced after treatment in the allergoid-treated group and remained unchanged in the placebo-treated group. There was a significant (p less than 0.001) correlation between the skin prick test end point and symptom scores during the season. Serum grass-pollen IgG titrated by a solid-phase radioimmunoassay with Staphylococcus A protein was significantly (p less than 0.01, Wilcoxon W test) increased after treatment with allergoid, but there was no significant correlation between IgG titer and symptom scores during the season. Serum grass-pollen IgE increased (p less than 0.04, Wilcoxon W test) in the treated group but there was no correlation with symptom scores.

Adult↗