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The acetone, alcohol and aqueous extracts of the fruits and stem bark of Acacia nilotica subspp. tomentosa, astringens and nilotica showed molluscicidal activity against the two snail species which transmit schistosomiasis in the Sudan. Being effective against Bulinus truncatus and Biomphalaria pfeifferi, extracts of the Acacia nilotica subspecies may be promising vegetable molluscicides.
The effect of capsule size on the permeability of gelatin-acacia microcapsules toward sodium chloride was investigated. Gelatin-acacia microcapsules containing olive oil were prepared by phase separation. The encapsulated olive oil was extracted with acetone and the acetone-loaded microcapsules dispersed in acetone were fractionated by a series of mesh screens. The core material of acetone than was replaced by water. The permeability of each capsule fraction toward sodium chloride was estimated from the change in electrical conductance with time of the mixture of microcapsule suspension and sodium chloride solution. The permeability decreased with decreasing capsule size. Structured water in and around the capsule wall may be the cause of the observed size effect.
Rhizobium wild-type strain GRH2 was originally isolated from the tree, Acacia cyanophylla, and has a broad host-range which includes herbaceous legumes, such as Phaseolus and Trifolium species. Here we show that strains of Rhizobium sp. GRH2, into which heterologous nodD alleles have been introduced, produce a large diversity of both sulphated and non-sulphated lipo-chitin oligosaccharides (LCOs). Most of the molecular species contain an N-methyl group on the reducing-terminal N-acetyl-glucosamine. The LCOs vary in the nature of the fatty acyl chain and in the length of the chitin backbone. The majority of the LCOs have an oligosaccharide chain length of five GlcNAc residues, but a few are oligomers having six GlcNAc units. LCOs purified from GRH2 are able to induce root hair formation and deformation on Acacia cyanophylla and A. melanoxylon plants. We show that an N-vaccenoyl-chitopentaose bearing an N-methyl group is able to induce nodule primordia on Phaseolus vulgaris, A. cyanophylla, and A. melanoxylon, indicating that for these plants an N-methyl modification is sufficient for nodule primordia induction.
The leaves of Robinia pseudo-acacia L. (Fabaceae) were evaluated as a biomonitors of heavy metal contamination in Denizli city, Turkey. Concentrations of Fe, Zn, Pb, Cu, Mn and Cd were determined in washed and unwashed leaves and soils collected from a wide range of sites with different degrees of metal pollution (industry, urban roadside, suburban) and from a rural (control) site by atomic absorption spectrometry. All the elements that measured were found to be at high levels in samples collected at industrial sites, except for lead and copper which were found at high levels in samples collected from urban roadsides that associated with the road traffic. The strong correlation between the degree of contamination and concentrations in all plant leaves assessed display that the leaves of R. pseudo-acacia reflect the environmental changes accurately, and that they seem as an effective biomonitor of environmental quality in areas subjected to industrial and traffic pollutions.
Entomophthora leyteensis Villacarlos & Keller sp. nov., a species of Entomophthorales infecting the whitefly Tetraleurodes acaciae on Gliricidia sepium in the Philippines is described. Disease prevalence monitored weekly for 8 weeks indicated that the fungus could cause 8-31% infection within the whitefly population. Epizootics due to this fungus occurred in Inopacan, Leyte. Sampling live whitefly adults and dissecting them on glass slides for microscopic examination of fungal structures was found to give a better measure of prevalence than actual counts of infected insect cadavers. E. leyteensis is an important mortality factor for T. acaciae. Some speculations on the origin of the fungus are discussed here.
A greenhouse study was conducted to evaluate the potential use of two legume species, Acacia auriculiformis and Leucaena leucocephala for growth on ameliorated lagoon ash with or without nitrogen (N(2))-fixing bacteria inoculation. Even though amendments of 30% (w/w) vermiculite or with sewage sludge compost were added to improve the chemical and physical limitations of lagoon ash, significant suppressions in biomass and plant nutrient content were found with ameliorated lagoon ash in comparison to an agricultural soil. The high proportion of clay-sized (<53 microm) ash particles limited root growth. In addition, heavy metal toxicity was a possible factor contributing to poor seedling growth. Higher plant productivity resulted from the sewage sludge compost-amended lagoon ash than with vermiculite due to a greater contribution of plant nutrients in the compost. Nodulation was inhibited in ameliorated lagoon ash but not in agricultural soil. High pH and electrical conductivity and elevated toxic metals may be important parameters that limit bacterial activity. Both species showed potential to establish on amended lagoon ash, with Acacia auriculiformis being the best adapted.
The species of thrips found on Acacia constitute a major component of the Australian thrips fauna, with at least 235 species in more than 30 genera, many of these being in the process of description as new. These thrips exhibit social behaviours, ranging from solitary and colonial species to a variety of more complex social organisations. Furthermore, the domiciliary habits of these species include domicile construction, gall induction, and opportunistic use of abandoned galls and domiciles. This suite of thrips also includes a variety of inquiline and kleptoparasitic taxa. To understand how these various traits have evolved and interact in this diverse group, we have reconstructed a phylogeny for 42 species of thrips associated with Acacia around Australia. We obtained DNA sequence data from two nuclear genes (Elongation Factor-1alpha and wingless) and one mitochondrial gene (cytochrome oxidase I) and analysed these using maximum parsimony and maximum likelihood methods. A phylogeny resulting from such analysis allows inference of evolutionary transitions in domiciliary habits, social organisations, and parasitic behaviours. Gall induction and parasitic behaviour are postulated to each have a single origin, with no losses of either trait. Once parasitism evolved a remarkable radiation followed that allowed exploitation of very diverse hosts. Our data do not allow hypotheses of single versus multiple origins of domicile building to be resolved while opportunistic gall use appears to have arisen several times.
The main chemical and physical features of the Acacia senegal exudate gum and its molecular fractions isolated by chromatographies were determined using a wide variety of methods. Three main molecular fractions were isolated after hydrophobic interaction chromatography (HIC) and biochemical analyses confirmed the presence of an arabinogalactan-peptide (FI), an arabinogalactan-protein (FII), and a glycoprotein (FIII) fraction as described commonly in the literature. Further purification of FIII using size exclusion chromatography revealed three distinct populations. A wide molecular weight distribution within each population with the presence of at least two distinct molecular species per population was identified by high performance size exclusion chromatography coupled to on line multi-angle laser light scattering (HPSEC-MALLS). In addition, both sugars content (neutral and uronic acids) and UV profiles revealed that FIII was composed of a continuum of molecular species differing both by their protein-to-sugar ratio and molecular weight. FI and FII had average molecular weight M(w) of 2.86 x 10(5) and 1.86 x 10(6) g.mol(-1), respectively, and a low polydispersity index (M(w)()/M(n) approximately 1.3). The three populations identified in FIII after HIC separation had M(w) of 2.67 x 10(6), 7.76 x 10(5), and 2.95 x 10(5) g.mol(-1) and very low polydispersity indexes (1.13, 1.04, and 1.01). Estimation of the polypeptide backbone length in the three fractions gave 43, 2253, and 4443 amino acid residues, respectively, hydroxyproline (Hyp) and serine being the most prominent residues within FI and FII, Hyp and Asx (asparagine + aspartic acid) within FIII. Secondary structure prediction from circular dichroism data resulted in polyproline II, beta-sheet, and random coil structures for FII and FIII, whereas no secondary structure was identified in FI. The existence of exposed tryptophanyl residues to the solvent was noticed by fluorescence in FII and FIII, tryptophan residues being absent from FI. In addition, 8-5' non cyclic diferulic acid was identified to be covalently linked to carbohydrate moieties of FII. Infrared spectroscopy identified the different vibrations of saccharidic and peptidic bonds with absorbance amplitudes in agreement with sugar and protein elementary analyses. Titration measurements in order to evaluate the number of charges on total Acacia gum and its molecular fractions revealed that 100% of charges came from polysaccharidic moieties (i.e., glucuronic acids) in FI. Charges coming from polysaccharidic moieties were of 91.3% and 37.9% for FII and FIII, respectively, the remaining 8.7% and 62.1% charges in FII and FIII molecular fractions coming from the polypeptidic backbone.
The chemical composition, digestibility and toxin contents of two wild legumes: Styphnolobium burseroides and Acacia bilimekii, collected in a semi-arid zone of Mexico, were determined. Both legumes had a high fiber content. The seeds of Styphnolobium burseroides had a low protein content (14%), and the pod a high content of reducing sugars. However the seeds of Acacia bilimekii had a high protein concentration (35%). The seed proteins were low in sulphur amino acids and tryptophan in both legumes but were rich in lysine. Trypsin inhibitors and lectins were present in low concentrations; alkaloids and cyanogenic glucosides were not detected. The in vitro digestibility for monogastric animals was low but the same test with ruminal juice showed a high digestibility for both legumes. Based on their chemical composition and digestibility, these legumes could be a good alternative source in the feeding of ruminants.
AIMS: To assess the protective effect of gum acacia (GA) on the performance of Lactobacillus paracasei NFBC 338 during spray-drying, subsequent storage and exposure of the culture to porcine gastric juice. METHODS AND RESULTS: For these studies, Lact. paracasei NFBC 338 was grown in a mixture of reconstituted skim milk (10% w/v) and GA (10% w/v) to mid log phase and spray-dried at outlet temperatures between 95 and 105 degrees C. On spray drying at the higher air outlet temperature of 100-105 degrees C, the GA-treated culture displayed 10-fold greater survival than control cells. Probiotic lactobacilli in GA-containing powders also survived dramatically better than untreated cultures during storage at 4-30 degrees C for 4 weeks. A 20-fold better survival of the probiotic culture in GA-containing powders was obtained during storage at 4 degrees C while, at 15 and 30 degrees C, greater than 1000-fold higher survival was obtained. Furthermore, the viability of probiotic lactobacilli in GA-containing powders was 100-fold higher when exposed to porcine gastric juice over 120 min compared with the control spray-dried culture. CONCLUSIONS: The data indicate that GA has applications in the protection of probiotic cultures during drying, storage and gastric transit. SIGNIFICANCE AND IMPACT OF THE STUDY: Gum acacia treatment for the manufacture of probiotic-containing powders should result in more efficient probiotic delivery to the host gastrointestinal tract.
Water-soluble dietary fibers (WSDF) are generally thought to lower cholesterol. This study compared the cholesterol-lowering effects of a medium viscosity WSDF mixture (psyllium, pectin, guar gum and locust bean gum) with an equal amount of WSDF from acacia gum, which has a lower viscosity. Hypercholesterolemic males (n = 13) and females (n = 16) were randomly assigned to one of two WSDF treatments provided in a low-calorie powder form for mixing into beverages (< 4 kcal/serving). Subjects were instructed to mix powders into their usual beverages and to consume them three times daily (5 g WSDF/serving) for 4 weeks while consuming their typical fat-modified diets. Exercise and body weights were also held constant. The WSDF mixture yielded a 10% decrease in plasma total cholesterol (from 251 +/- 20 to 225 +/- 19 mg/dL; p < 0.01), and a 14% reduction in low-density lipoprotein cholesterol (from 167 +/- 14 to 144 +/- 14 mg/dL; p < 0.001). No significant changes in plasma high-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol or triglycerides were observed. In contrast, the acacia gum-treated group showed no change in any plasma lipid parameters. The WSDF treatments did not produce significant changes in mean dietary intakes within or between treatment groups. These data support previous findings that a diet rich in select WSDF can be a useful cholesterol-lowering adjunct to a fat-modified diet, but that caution should be exercised in ascribing cholesterol-lowering efficacy to dietary fibers based solely on their WSDF classification. Finally, WSDF viscosity is a potential cholesterol-lowering factor to be explored further.
Exudative gums from two Australian Acacia species (A. pycnantha and A. baileyana) and gum arabic (from A. senegal) were fed to rats at graded levels (0, 20, 40, 80 g/kg), replacing cellulose in purified diets containing cholesterol plus cholic acid. Compared with consumption of the control diet containing cellulose only, consumption of the gums had no significant effects on concentrations of plasma or liver cholesterol. Plasma triacylglycerol concentrations were higher in rats fed gum arabic, whereas liver triacylglycerols were lower in rats fed the gums. The gums did not affect the total pool of volatile fatty acids in the ceca, as compared with results in controls, but did promote the relative contribution of propionate at the expense of acetate. In rats fed the diet containing cellulose (80 g/kg) the proportions of cecal acetate:propionate:butyrate were 76:15:9, whereas in the rats fed A. pycnantha gum, gum arabic and A. baileyana gum (80 g/kg) the ratios were 42:54: 4, 35:46:19 and 43:53:4, respectively. The low apparent fermentability of the gums was confirmed by the accumulation of non-starch polysaccharides in cecal digesta. In rats fed 80 g/kg A. pycnantha gum, 3.44 g of soluble non-starch polysaccharides was measured in the ceca, which was 58% of the dry weight of the cecal contents. We conclude that the biological activities of the Australian Acacia gums were similar to those of gum arabic and that these gums may have potential value as human food ingredients.
Concentrations of extractable and total phosphorus in leaves, stem, root and nodules of 12-week-old seedlings of two provenances of Acacia mangium Willd. were analyzed to identify the fraction of phosphorus and the plant part most suitable for predicting the phosphorus nutritional status of the seedlings.For both provenances, concentrations of extractable phosphorus were more sensitive to changes in soil phosphorus status and varied less among different plant parts than concentrations of total phosphorus. Concentrations of extractable phosphorus in the youngest fully expanded leaf (Leaf 3 from the apex) and the next two older leaves correlated closely with seedling dry mass and may be used to assess the phosphorus nutritional status of Acacia mangium seedlings.
We examined the influences of selected environmental variables on stomatal behavior and regulation of transpiration in 26-month-old Acacia koa Gray (koa) stands planted at spacings of 1 x 1 m or 2.5 x 2.5 m and grown without irrigation. Field measurements were made during recovery from an extended 60-day dry period with only 38 mm of precipitation. Biomass and leaf area were also measured at 3-month intervals over the first 24 months after planting and again following completion of the transpiration (T) and stomatal conductance (g(s)) measurements at about 26 months after planting. Transpiration was measured as sap flow through intact branches by a heat balance method. After a 22-day period during which 130 mm of rain were recorded, average T was substantially higher in the 2.5 x 2.5 m stand on both a leaf area and ground area basis even though leaf area index was about 3.5 times higher in the 1 x 1 m stand. After an additional 25 mm of rain during an 8-day period, T was still slightly higher on a leaf area basis in the 2.5 x 2.5 m stand but was about 3 times higher on a ground area basis in the 1 x 1 m stand. A strong stomatal response to humidity limited the increase in T with increasing evaporative demand. Values of g(s) in koa phyllodes were comparable to those reported for leaves of other mesic tropical forest trees, but were several times higher than those reported for Acacia species native to arid and semi-arid regions. The 1 x 1 m planting yielded three times more biomass per unit ground area than the 2.5 x 2.5 m planting. However, greater stand density, which resulted in more rapid depletion of soil water between rainfall inputs, was associated with lower growth efficiency and lower radiation conversion efficiency.
Thirteen Acacia species were classified into three groups according to effective nodulation response patterns with fast- and slow-growing tropical strains of Rhizobium. The first group nodulated effectively with slow-growing, cowpea-type Rhizobium strains; the second, with fast-growing Rhizobium strains; and the third, with both fast- and slow-growing Rhizobium strains. The Rhizobium requirements of the Acacia species of the second group were similar to those of Leucaena leucocephala.
The influences of seasons, plant age, and physicochemical properties of the soil on surface and deep biological arbuscular mycorrhizal fungus parameters associated with Acacia albida were assessed in different areas of Senegal. More indigenous arbuscular mycorrhizal propagules were found in the localities of the Sudano-Guinean zone (Djinaki and Kabrousse) than in those of the Sahelian zone (Louga and Diokoul), and species belonging to the genera Glomus, Gigaspora, Acaulospora, and Sclerocystis prevailed. The numbers of total and viable spores increased more during the rainy season than during the dry season (about 108% more total spores and 262% more viable spores). Similarly, both total and viable spores were more prevalent around young Acacia trees than old trees. However, the intensities of root colonization did not differ in each ecoclimatic zone.
Forty rhizobia nodulating four Acacia species (A. gummifera, A. raddiana, A. cyanophylla, and A. horrida) were isolated from different sites in Morocco. These rhizobia were compared by analyzing both the 16S rRNA gene (rDNA) and the 16S-23S rRNA spacer by PCR with restriction fragment length polymorphism (RFLP) analysis. Analysis of the length of 16S-23S spacer showed a considerable diversity within these microsymbionts, but RFLP analysis of the amplified spacer revealed no additional heterogeneity. Three clusters were identified when 16S rDNA analysis was carried out. Two of these clusters include some isolates which nodulate, nonspecifically, the four Acacia species. These clusters, A and B, fit within the Sinorhizobium lineage and are closely related to S. meliloti and S. fredii, respectively. The third cluster appeared to belong to the Agrobacterium-Rhizobium galegae phylum and is more closely related to the Agrobacterium tumefaciens species. These relations were confirmed by sequencing a representative strain from each cluster.
The aqueous extracts of Acacia nilotica and Hibiscus sabdariffa were tested for anti-inflammatory, analgesic and antipyretic activities in animal models. Acacia nilotica extract had an inhibitory effect on carrageenan induced paw edema and yeast-induced pyrexia in rats. It also produced a significant increase in the hot plate reaction time in mice. Hibiscus sabdariffa extract had no effect on paw edema but had an inhibitory effect on yeast induced pyrexia and a significant effect on the hot plate reaction time. Among the phytoconstituents found in both plants, flavanoids, polysaccharides and organic acids may be mainly responsible for their pharmacological activities.