A new density gradient system of modified gum acacia solution for the cell separation.
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Animals↗
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Acacias and Aesculapius. Walter Edmund Roth, 1861-1933.
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Anthropology↗
Hypoglycaemic and hypocholesterolaemic effects of proteins of Acacia milanoxylon and Bauhinia retusa wild leguminous seeds in young albino rats.
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Animals↗
[Poisoning of horses by the bark of the false acacia (Robinia pseudoacacia)].
The present study describes the poisoning due to Robinia pseudoacacia in two horses. One of the horses showed mainly intestinal symptoms such as decreased intestinal motility and obstipation of the pelvic flexure. In the second animal central nervous symptoms were predominant. It showed intermittent phases of somnolence alternating with phases of excitation and head pressing. In addition mydriasis and a lacking menace response could be observed. Sensation to the head and the spinal reflexes were reduced. Symptomatic treatment was initiated in both animals and recovery occurred within 2 days.
Animals↗
Evolutionary change from induced to constitutive expression of an indirect plant resistance.
Induced plant resistance traits are expressed in response to attack and occur throughout the plant kingdom. Despite their general occurrence, the evolution of such resistances has rarely been investigated. Here we report that extrafloral nectar, a usually inducible trait, is constitutively secreted by Central American Acacia species that are obligately inhabited by ants. Extrafloral nectar is secreted as an indirect resistance, attracting ants that defend plants against herbivores. Leaf damage induces extrafloral nectar secretion in several plant species; among these are various Acacia species and other Fabaceae investigated here. In contrast, Acacia species obligately inhabited by symbiotic ants nourish these ants by secreting extrafloral nectar constitutively at high rates that are not affected by leaf damage. The phylogeny of the genus Acacia and closely related genera indicate that the inducibility of extrafloral nectar is the plesiomorphic or 'original' state, whereas the constitutive extrafloral nectar flow is derived within Acacia. A constitutive resistance trait has evolved from an inducible one, obviously in response to particular functional demands.
Acacia↗
Characterization of tropical tree rhizobia and description of Mesorhizobium plurifarium sp. nov.
A collection of strains isolated from root nodules of Acacia species in Senegal was analysed previously by electrophoresis of total cell protein, auxanographic tests, rRNA-DNA hydridization, 16S rRNA gene sequencing, DNA base composition and DNA-DNA hybridization [de Lajudie, P., Willems, A., Pot, B. & 7 other authors (1994). Int J Syst Bacteriol 44, 715-733]. Strains from Acacia were shown to belong to two groups, Sinorhizobium terangae, and a so-called gel electrophoretic cluster U, which also included some reference strains from Brazil. Further taxonomic characterization of this group using the same techniques plus repetitive extragenic palindromic-PCR and nodulation tests is presented in this paper. Reference strains from Sudan and a number of new rhizobia isolated from nodules of Acacia senegal, Acacia tortilis subsp. raddiana and Prosopis juliflora in Senegal were included. As a result of this polyphasic approach, the creation of a new species, Mesorhizobium plurifarium, is proposed for a genotypically and phenotypically distinct group corresponding to the former cluster U and containing strains isolated from Acacia, Leucaena, Prosopis and Chamaecrista in West Africa (Senegal), East Africa (Sudan) and South America (Brazil). The type strain of Mesorhizobium plurifarium ORS 1032 has been deposited in the LMG collection as LMG 11892.
Acacia↗
Some preparative variables influencing the properties of W/O/W multiple emulsions.
Water-in-oil-in-water multiple emulsions of chloroquine diphosphate were prepared, using olive oil, arachis oil, Span 80, gelatin, acacia and Tween 80. Emulsifiers were employed individually or in combination. An attempt was made to correlate preparative variables with stability and drug release of multiple emulsions of roughly comparative particle size. When the emulsions were satisfactorily stabilized by the optimum blend of surfactants the rate of release varied with the nature and/or combination of emulsifiers employed. The possible effects of phase-inversion temperature, spontaneous emulsification and liquid crystal stabilization on the systems have been discussed. The mechanism probably involved complex interfacial adsorption and hydrodynamic phenomena in the presence of natural oils, co-surfactants and natural stabilizers of individual HLB number, particularly when acacia is present in the system. This could be attributed to the existence of protein in some species of acacia, since there are about 130 species of acacia, the gummy exudations of which are considered official in compendia. The protein content could be a reasonable additional specification for acacia as an emulsifier.
Acacia↗
The mineral scoring technique and evaluation of indigenous browse species as natural mineral phytocentres for goats in African rangelands.
The utilization and evaluation of indigenous browse species as natural mineral phytocentres for goats was examined by the combined use of mineral concentrations, mineral scores, browse accessibility and abundance in the Ankole rangeland, Uganda. The species Grewia bicolor and Carissa edulis with > 140% mineral scores and > 70% accessibility were the most valuable mineral phytocentres and were the victims of overgrazing. Acacia albida and Acacia abyssinica with > 130% mineral scores but < 30% browse accessibility were valuable for the cut-and-carry feeding system. Species mineral scores at average and maximum dietary recommendations were < 60%, highlighting the mineral insufficiency of range browse for high-performance goats. Mineral supply potential was highest (35.0%) in the genus Acacia and lowest (5.3%) in Dichrostachsys. Browse accessibility was < 35%, in 69.2% of species. Acacia hockii was the most abundant species (24.5%) but had the lowest mineral score (17.7%). Browse species (90-100%) were deficient in Fe, Mn, Cu and Zn. The combined use of mineral concentrations and mineral scoring technique was superior to the use of mineral concentrations alone in defining mineral adequacy, deficiency and supply potential, making the mineral scoring technique a valuable tool in browse management.
Acacia↗
Postsecretory hydrolysis of nectar sucrose and specialization in ant/plant mutualism.
Obligate Acacia ant plants house mutualistic ants as a defense mechanism and provide them with extrafloral nectar (EFN). Ant/plant mutualisms are widespread, but little is known about the biochemical basis of their species specificity. Despite its importance in these and other plant/animal interactions, little attention has been paid to the control of the chemical composition of nectar. We found high invertase (sucrose-cleaving) activity in Acacia EFN, which thus contained no sucrose. Sucrose, a disaccharide common in other EFNs, usually attracts nonsymbiotic ants. The EFN of the ant acacias was therefore unattractive to such ants. The Pseudomyrmex ants that are specialized to live on Acacia had almost no invertase activity in their digestive tracts and preferred sucrose-free EFN. Our results demonstrate postsecretory regulation of the carbohydrate composition of nectar.
Acacia↗
A study of pollen prevalence in relation to pollen allergy in Malaysian asthmatics.
In this paper we report results of skin prick tests (SPT) using pollen extracts on 200 patients with clinical symptoms of asthma, and results of a parallel study in which pollen was collected and classified over a period of 18 months. The patients were outpatients from the University Hospital in Kuala Lumpur, Malaysia, while the pollen grains were collected with a spore trap placed in the campus of the University of Malaya, approximately one kilometer from the University Hospital. Pollen extracts of 3 grasses (Bahia, Bermuda, rough pigweed) and 2 flowering trees, Acacia and Melaleuca, were used in the SPT. Of the 29.5% asthmatics with positive SPT reactions, 21.5% were to one or more of the grass pollens, 21.5% to Acacia and 7.5% to Melaleuca pollen. Acacia and Bermuda grass extracts were the most allergenic, which agreed with results of the pollen collection which showed grass and Acacia pollen grains to be the two most commonly found pollens.
Acacia↗
Seasonal variation of macro and trace mineral contents in 14 browse species that grow in northeastern Mexico.
Leaves and twigs from shrub species consumed by range goats: Acacia berlandieri, Acacia farnesiana, Acacia greggii, Acacia rigidula, Celtis pallida, Cercidium macrum, Condalia obovata, Cordia boissieri, Desmanthus virgathus, Leucaena leucocephala, Leucophyllum texanum, Opuntia lindehimieri, Porlieria angustifolia, Prosopis glandulosa, and Ziziphus obtusifolia were evaluated for comparative seasonal contents of Ca, P, Mg K, Zn, Mn, Cu and Fe. Plants were collected in summer (September 12, 1992), fall (November 20, 1992), winter (February 20, 1993) and spring (May 22, 1993) in Marín, County, Nuevo Leon, Mexico. During spring and summer mineral concentrations were higher in general. Only Ca, Mg, K, and Fe were in substantial amounts in all seasons to meet adult goat requirements. With the exception of spring, shrubs had extremely low P concentrations. Manganese, Cu and Zn in most plants had low marginal levels to meet adult goat requirements. Moreover, potential intake of P, Mn, Cu and Zn in shrub species by goats weighing 50kg BW consuming 2.0kg per day DM was low. However, plants such as D. virgathus, L. texanum, P. glandulosa, L. leucocephala and C. macrum can be considered prominent components in diets of range goats because of their high mineral concentrations. It appears that ration formulations for range goats in northeastern Mexico should include P, Mn, Cu and Zn in all seasons of the year.
Journal Article↗
Kinetics of formation and functional properties of conjugates prepared by dry-state incubation of beta-lactoglobulin/acacia gum electrostatic complexes.
The formation of conjugates between beta-lactoglobulin and acacia gum based on electrostatic complexes formed at pH 4.2 was investigated upon dry-state incubation for up to 14 days at 60 degrees C and 79% relative humidity (RH). By means of SEC-HPLC and RP-HPLC, it was shown that the beta-lactoglobulin incubated alone was able to form polymers with molecular masses higher than 200 kDa until 50% of the initial monomeric protein disappeared after 14 days. In the presence of acacia gum at initial protein to polysaccharide weight mixing ratios of 2:1 and 1:2, only 35% of the initial beta-lactoglobulin monomers disappeared after 14 days. Using RP-HPLC, an apparent reaction order of 2 was found for the disappearance of monomeric beta-lactoglobulin both in the presence or absence of acacia gum. However, the reaction rate was faster in the absence of acacia gum. SDS-PAGE electrophoresis with silver staining confirmed the formation of beta-lactoglobulin/acacia gum conjugates. The solubility curves of the incubated beta-lactoglobulin showed a minimum around pH 4-5. By contrast, the minimum of solubility of the beta-lactoglobulin/acacia gum incubated mixtures shifted to lower pH values compared to initial mixtures. The conjugates exhibited higher foam capacity than the incubated protein as well as lower equilibrium air/water surface tension. Conjugation at ratio 1:2 led to increased interfacial viscosity (300 mN s m(-1) at 0.01 Hz) compared to beta-lactoglobulin alone (100 mN s m(-1) at 0.01 Hz), but similar interfacial elasticity (30-40 mN m(-1)). The foam capacity of the conjugates was significantly higher than that of the incubated beta-lactoglobulin as well as foam expansion and drainage time, especially at pH 5.3, i.e., higher than the pH of formation of the conjugates.
Chemical Phenomena↗
Novel yeast killer toxins provoke S-phase arrest and DNA damage checkpoint activation.
Certain strains of Pichia acaciae and Wingea robertsiae (synonym Debaryomyces robertsiae) harbour extranuclear genetic elements that confer a killer phenotype to their host. Such killer plasmids (pPac1-2 of P. acaciae and pWR1A of W. robertsiae) were sequenced and compared with the zymocin encoding pGKL1 of Kluyveromyces lactis. Both new elements were found to be closely related to each other, but they are only partly similar to pGKL1. As for the latter, they encode functions mediating binding of the toxin to the target cell's chitin and a hydrophobic region potentially involved in uptake of a toxin subunit by target cells. Consistently, mutations affecting the target cell's major chitin synthase (Chs3) protect it from toxin action. Heterologous intracellular expression of respective open reading frames identified cell cycle-arresting toxin subunits deviating structurally from the likewise imported gamma-subunit of the K. lactis zymocin. Accordingly, toxicity of both P. acaciae and Wingea toxins was shown to be independent of RNA polymerase II Elongator, which is indispensable for zymocin action. Thus, P. acaciae and Wingea toxins differ in their mode of action from the G1-arresting zymocin. Fluorescence-activated cell sorting analysis and determination of budding indices have proved that such novel toxins mediate cell cycle arrest post-G1 during the S phase. Concomitantly, the DNA damage checkpoint kinase Rad53 is phosphorylated. As a mutant carrying the checkpoint-deficient allele rad53-11 displays toxin hypersensitivity, damage checkpoint activation apparently contributes to coping with toxin stress, rather than being functionally implemented in toxin action.
Cell Cycle↗
Comparison of effects of surfactants with other MDR reversing agents on intracellular uptake of epirubicin in Caco-2 cell line.
P-glycoprotein (P-gp) actively pumps out a number of anticancer drugs, such as epirubicin, from tumor cells. P-gp is also expressed in the small intestine under normal physiological conditions. Inhibition of intestinal P-gp function using MDR reversing agents may enhance the oral bioavailability of some chemotherapeutic agents. Human colon adenocarcinoma (Caco-2) cell line expresses many characteristics of differentiated cells of the normal small intestine. Using Caco-2 as an in vitro intestinal model, the overall goal of the present study was to evaluate the MDR-reversing effects of some commonly used nonabsorptive pharmaceutical surfactants, such as Tween 20, Tween 80 and acacia on the intracellular accumulation of epirubicin by flow cytometry. Tween 20, Tween 80 or acacia all significantly increased intracellular accumulation of epirubicin with the highest enhancing effect for acacia and the lowest for Tween 20. Apart from progesterone, the enhancing effects of surfactants were better than those of non-surfactant MDR reversing agents such as verapamil, trifluoperazine and reserpine. In conclusion, our results demonstrate that progesterone, acacia, Tween 20 and Tween 80 are potent MDR modifiers of epirubicin in Caco-2 at concentrations that could be achieved in vivo. Use of surfactants in excipients may increase the intestinal absorption of some drugs through P-gp inhibition and thus improve drug bioavailability for P-gp substrate.
Antibiotics, Antineoplastic↗
Evaluation of five medicinal plants used in diarrhoea treatment in Nigeria.
Five medicinal plants [Acacia nilotica, Acanthospermun hispidum, Gmelina arborea, Parkia biglobosa and Vitex doniana] used in diarrhoeal treatment in Kaduna State, Nigeria, were investigated. This study was carried out on perfused isolated rabbit jejunum and castor oil-induced diarrhoea in mice. The aqueous methanol extracts (0.5, 1.0, 2.0 and 3.0 mg/ml) were generally found to cause a dose-dependent response in the isolated rabbit jejunum, though this was not uniform in all the plants. Gmelina arborea and Vitex doniana showed concentration dependent relaxation at low doses (0.5, 1.0 mg/ml), but showed no significant relaxation at higher doses (2.0, 3.0 mg/ml). Other extracts showed biphasic effects. For example, Acacia nilotica at 3.0 mg/ml caused initial relaxation quickly followed by contraction. In the castor oil-induced diarrhoeal, 100% protections were shown by extracts of Acacia nilotica and Parkia biglobosa (100, 200 mg/kg) while Vitex doniana showed a dose-dependent effect. The least protection was shown by Acanthospermun hispidum, at the same dose, when compared with the other four plants. The results obtained revealed that the aqueous methanol extracts of all the five medicinal plants investigated have pharmacological activity against diarrhoea. This may explain their use in traditional medicine for the treatment of diarrhoea.
Acacia↗
A land management history for central Queensland, Australia as determined from land-holder questionnaire and aerial photography.
Features of the land management history over a 125,755 km(2) area of central Queensland, Australia were determined from a variety of sources. A random sample of 205 site locations provided the basis for determining trends in land use. Trends in vegetation clearing were determined using sequential aerial photography for the sample sites, revealing a steady rate averaging nearly 1% of the region per annum over 41 years. This measure of sustained clearing over a large region is higher than recently published clearing rates from South America. Land types have been selectively cleared with over 90% of the Acacia on clay land type having been cleared. A land-holder questionnaire pertaining to the random sites yielded a response rate of 71% and provided information on vegetation clearing, ploughing, tree killing (ring-barking or tree poisoning), and fire frequency, season and intensity. The land-holder responses were compared with independent data sources where possible and revealed no mis-information. However, land-holders may have been marginally less likely to respond if the sample area had been cleared, although this effect was not statistically significant. Ploughing and tree killing are variable depending on land type, but the former has affected about 40% of the Acacia on clay land type, effectively eliminating options for natural regrowth. The proportion of decade-site combinations that were reported as having no fires increased from 22% in the 1950s to an average of 42% for subsequent decades, although the reporting of more than one fire per decade has been relatively constant through the study period. The reporting of at least one fire per decade varies from 46% for the Acacia on sand land type to 77% for the Eucalypt on sand land type for decade-site combinations. Fires are more intense when associated with clearing than in uncleared vegetation, but the proportion of cool and hot fires is relatively constant between land types in uncleared vegetation. Nearly all fires reported were either in spring or summer and this seasonally restricted regime is probably at variance with Aboriginal fire regimes. This study describes the rapid transformation of central Queensland. This has yielded substantially increased agricultural production but may also result in a range of negative impacts and these are discussed.
Acacia↗
The development of immunoassays to identify and quantify species source of gum arabic.
Gum arabic from Acacia senegal is commonly used as an additive in foodstuffs. Adulteration of gum arabic by other gums is a potential problem for reasons of safety and quality. This study aimed to develop and evaluate the use of enzyme-linked immunosorbent assays (ELISAs) for the detection of potential adulterants of gum arabic. Indirect competitive ELISAs (IC-ELISAs) were developed using the monoclonal antibodies SY CC7 (A. senegal), SY HH3 (Acacia seyal), and SY J1A1 (Combretum erythrophyllum). All IC-ELISAs had a working range of 0.005-10 mg/mL. The antibodies used were tested using the IC-ELISAs for cross-reactivity with other Acacia species and other gums. The antibodies were very specific for their respective antigens. Significant cross-reactivity was found for SY CC7 (between A. senegal and A. melliferae) and SY J1A1 (between C. erythrophyllum and A. seyal). The IC-ELISA was adapted further to test confectionery samples for the presence of gum arabic, which was successful, although recovery rates were reduced. Both IC- and plate trapped antigen ELISA (PTA-ELISA) formats were able to distinguish an adulterated sample of gum arabic when blended with either A. seyal or C. erythrophyllum. The PTA-ELISA was more sensitive for A. seyal than the IC-ELISA, but both were equally sensitive for C. erythrophyllum. The results suggest that the antibodies SY CC7, SY HH3, and SY J1A1 could be used in combination with each other for the detection of potential adulterants of A. senegal and the detection of gum arabic in foodstuffs.
Acacia↗
Injury to murine airway epithelial cells by pollen enzymes.
BACKGROUND: Pollens are important triggers for asthma but the mechanism of sensitisation to their proteins remains poorly understood. The intrinsic protease activity of some allergens may contribute to sensitisation by disrupting the integrity of the airway epithelial barrier. Pollens release a variety of enzymes, including proteases, upon hydration. The hypothesis that such enzymes might be able to damage airway epithelial cells was therefore tested. METHODS: Diffusates from pollens of Lolium perenne (ryegrass), Poa pratensis (Kentucky bluegrass), Acacia longifolia (Sydney golden wattle), or Casuarina distyla (she-oak) were incubated with mouse tracheal epithelial cells in culture and cellular detachment was quantified using a methylene blue dye binding assay. RESULTS: Diffusates prepared using 100 mg/ml of pollen caused detachment of 30-90% of airway epithelial cells in separate experiments. Within each experiment comparable detachment was observed with all diffusates tested, although total protein in the diffusates varied markedly between species. Viability of the cells recovered after exposure to Acacia diffusate was higher than after detachment by exposure to Lolium diffusate. Cellular detachment by all of the diffusates could be almost completely inhibited by addition of 10% serum. Aprotinin, an inhibitor of serine proteases, partially blocked activity in diffusates of Lolium pollen but not of Acacia pollen. In contrast, alpha 1-protease inhibitor and secretory leucocyte protease inhibitor (SLPI) were not able to block the activity of either diffusate at concentrations which inhibited cellular detachment by trypsin. CONCLUSIONS: Proteases released by pollens are able to cause detachment of airway epithelial cells from their substratum in vitro and may not be effectively inhibited by endogenous antiproteases.
Acacia↗