Exploring the mechanism of transformation in Acacia nilotica (Linn.) triggered by colchicine seed treatment.

BACKGROUND: Acacia nilotica Linn. is a widely distributed tree known for its applications in post-harvest and medicinal horticulture. However, its seed-based growth is relatively slow. Seed is a vital component for the propagation of A. nilotica due to its cost-effectiveness, genetic diversity, and ease of handling. Colchicine, commonly used for polyploidy induction in plants, may act as a pollutant at elevated levels. Its optimal concentration for Acacia nilotica's improved growth and development has not yet been determined, and the precise mechanism underlying this phenomenon has not been established. Therefore, this study investigated the impact of optimized colchicine (0.07%) seed treatment on A. nilotica's morphological, anatomical, physiological, fluorescent, and biochemical attributes under controlled conditions, comparing it with a control. RESULTS: Colchicine seed treatment significantly improved various plant attributes compared to control. This included increased shoot length (84.6%), root length (53.5%), shoot fresh weight (59.1%), root fresh weight (42.8%), shoot dry weight (51.5%), root dry weight (40%), fresh biomass (23.6%), stomatal size (35.9%), stomatal density (41.7%), stomatal index (51.2%), leaf thickness (11 times), leaf angle (2.4 times), photosynthetic rate (40%), water use efficiency (2.2 times), substomatal CO2 (36.6%), quantum yield of photosystem II (13.1%), proton flux (3.1 times), proton conductivity (2.3 times), linear electron flow (46.7%), enzymatic activities of catalase (25%), superoxide dismutase (33%), peroxidase (13.5%), and ascorbate peroxidase (28%), 2,2-diphenyl-1-picrylhydrazyl-radical scavenging activities(23%), total antioxidant capacity (59%), total phenolic (23%), and flavonoid content (37%) with less number of days to 80% germination (57.1%), transpiration rate (53.9%), stomatal conductance (67.1%), non-photochemical quenching (82.8%), non-regulatory energy dissipation (24.3%), and H2O2 (25%) and O-2 levels (30%). CONCLUSION: These findings elucidate the intricate mechanism behind the morphological, anatomical, physiological, fluorescent, and biochemical transformative effects of colchicine seed treatment on Acacia nilotica Linn. and offer valuable insights for quick production of A. nilotica's plants with modification and enhancement from seeds through an eco-friendly approach.

Characterization of a plant S-adenosylmethionine synthetase from Acacia koa.

The Acacia koa S-adenosylmethionine (SAM) synthetase was identified from transcriptome data and cloned into the T7-expression vector pEt14b. Assays indicate a thermoalkaliphic enzyme which tolerates conditions up to pH 10.5, 55 °C and 3 M KCl. In vitro examples of plant SAM-synthetase activity are scarce, however this study provides supporting evidence that these extremophilic properties may actually be typical for this plant enzyme. Enzyme kinetic constants (Km = 1.44 mM, Kcat = 1.29 s-1, Vmax 170 µM. min-1) are comparable to nonplant SAM-synthetases except that substrate inhibition was not apparent at 10 mM ATP/L-methionine. Methods were explored in this study to reduce feedback inhibition, which is known to limit SAM-synthetase activity in vitro. Four single-point mutation variants of the Acacia koa SAM-synthetase were produced, each with varying degrees of reduced reaction rate, greater sensitivity to product inhibition and loss of thermophilic properties. Although an enhanced mutant was not produced, this study describes the first mutagenesis of a plant SAM-synthetase. Overcoming feedback inhibition was accomplished by the addition of organic solvent to enzyme assays. Acetonitrile, methanol or dimethylformamide, when included as 25% of the assay volume, improved total SAM production by 30-65%.

Amelioration of 5-Fluorouracil Induced Nephrotoxicity by Acacia catechu through Overcoming Oxidative Damage and Inflammation in Wistar Rats.

AIM: The research intended to explore the possible nephroprotective potential of the ethyl acetate fraction derived from Acacia catechu leaves against nephrotoxicity brought about by 5-fluorouracil (5-FU) in Wistar rats. BACKGROUND: While possessing strong anticancer properties, 5-FU is hindered in its therapeutic application due to significant organ toxicity linked to elevated oxidative stress and inflammation. OBJECTIVE: The study is undertaken to conduct an analysis of the ethyl acetate fraction of A. catechu leaves both in terms of quality and quantity, examining its impact on different biochemical and histopathological parameters within the context of 5-FU-induced renal damage in rats and elucidation of the mechanism behind the observed outcomes. METHODOLOGY: Intraperitoneal injection of 5-FU at a dosage of 20 mg/kg/day over 5 days was given to induce nephrotoxicity in rats. The evaluation of nephrotoxicity involved quantifying serum creatinine, urea, uric acid, and electrolyte concentrations. Furthermore, superoxide dismutase, catalase antioxidant enzymes, and TNF-α concentration in serum were also measured. RESULTS: 5-FU injection led to the initiation of oxidative stress within the kidneys, leading to modifications in renal biomarkers (including serum creatinine, urea, uric acid, and Na+, K+ levels), and a reduction in antioxidant enzymes namely superoxide dismutase and catalase. Notably, the presence of the inflammatory cytokine TNF-α was significantly elevated due to 5-FU. Microscopic examination of renal tissue revealed tubular degeneration and congestion. However, treatment involving the ethyl acetate fraction derived from A. catechu leaves effectively and dose-dependently reversed the changes observed in renal biomarkers, renal antioxidant enzymes, inflammatory mediators, and histopathological features, bringing them closer to normal conditions. The observed recuperative impact was mainly attributed to the antioxidant and antiinflammatory properties of the fraction. CONCLUSION: The ethyl acetate fraction of A. catechu leaves exhibited a mitigating influence on the renal impairment caused by 5-FU, showcasing its potential as a nephroprotective agent capable of preventing and ameliorating 5-FU-induced nephrotoxicity.

Insulin secretory actions of ethanolic extract of Acacia arabica bark in high fat-fed diet-induced obese Type 2 diabetic rats.

Acacia arabica commonly known as 'babul' has been widely used for the treatment of numerous diseases, including diabetes due to their potential pharmacological actions. The aim of the present study was to investigate the insulinotropic and antidiabetic properties of ethanol extract of Acacia arabica (EEAA) bark through in vitro and in vivo studies in high fat-fed (HFF) rats. EEAA at 40-5000 µg/ml significantly increased (P<0.05-0.001) insulin secretion with 5.6 and 16.7 mM glucose, respectively, from clonal pancreatic BRIN BD11 ß-cells. Similarly, EEAA at 10-40 µg/ml demonstrated a substantial (P<0.05-0.001) insulin secretory effect with 16.7 mM glucose from isolated mouse islets, with a magnitude comparable to 1 µM glucagon-like peptide-1 (GLP-1). Diazoxide, verapamil, and calcium-free conditions decreased insulin secretion by 25-26%. The insulin secretory effect was further potentiated (P<0.05-0.01) with 200 µM isobutylmethylxanthine (IBMX; 1.5-fold), 200 µM tolbutamide (1.4-fold), and 30 mM KCl (1.4-fold). EEAA at 40 µg/ml, induced membrane depolarization and elevated intracellular Ca2+ as well as increased (P<0.05-0.001) glucose uptake in 3T3L1 cells and inhibited starch digestion, glucose diffusion, dipeptidyl peptidase-IV (DPP-IV) enzyme activity, and protein glycation by 15-38%, 11-29%, 15-64%, and 21-38% (P<0.05, 0.001), respectively. In HFF rats, EEAA (250 mg/5 ml/kg) improved glucose tolerance, plasma insulin, and GLP-1 levels, and lowered DPP-IV enzyme activity. Phytochemical screening of EEAA revealed the presence of flavonoids, tannins and anthraquinone. These naturally occurring phytoconstituents may contribute to the potential antidiabetic actions of EEAA. Thus, our finding suggests that EEAA, as a good source of antidiabetic constituents, would be beneficial for Type 2 diabetes patients.

Antioxidant and Hepatoprotective Activities of Acacia jacquemontii Stem Extract against High-fat and CCl4-induced Liver Injury in Rat's Model.

BACKGROUND: Chronic liver injury leads to liver inflammation and fibrosis, activating myofibroblasts in the liver and secreting extracellular matrix proteins that make the fibrous scar. OBJECTIVES: The purpose of our study was to characterize the polyphenolic content present in Acacia jacquemontii stem and evaluate its antioxidant and hepatoprotective activity. METHODS: The phenolic contents in Acacia jacquemontii polyphenolic extract (AJPPE) were characterized using high-performance liquid chromatography (HPLC). The hepatoprotective and antioxidant activity of AJPPE were determined through biochemical parameters (ALT, AST, and ALP), lipid profile (TC, TG, HDL, and LDL), antioxidant biomarkers (SOD, LPO, GSH, and CAT), anti-fibrotic activity (collagen deposition), and histopathological analysis. RESULTS: HPLC analysis of AJPPE showed the presence of polyphenols, including chlorogenic acid, P-coumaric acid, caffeic acid, and kaempferol, in a remarkable therapeutic range. Results of the in vivo analysis showed a significant decrease in the level of lipid profile, including LDL (low-density lipoprotein), TC (total cholesterol), triglycerides, liver function markers (AST, ALT, and ALP), collagen deposition and significantly increased the level of anti-oxidative biomarkers (CAT, SOD, LPO, and GSH) by using AJPPE. CONCLUSION: The above-mentioned results have shown that AJPPE possesses significant antioxidative and hepatoprotective effects. Furthermore, histopathological results also supported the antioxidant and hepatoprotective potential of AJPPE.

Phytoremediation of crude oil contaminated soil using Sudanese plant species Acacia sieberiana Tausch.

Phytoremediation is a new technology for cleaning contaminated soil with crude oil. Oil pollution is a serious problem worldwide; the aim of this study was to use the plant for Phytoremediation. Leguminous plant Acacia seiberiana Tausch was tested for it is efficiency to remediate soil polluted with 0.5, 1, 1.5 and 2% (w/w) crude oil and it is the ability to enhance the activity of soil microorganisms. Plant parameters, degradation percentage, Total Petroleum Hydrocarbon and bacterial count were measured. Results showed that the concentration of the crude oil did not affect plant growth indicating the significant success of the Phytoremediation process. Shoot length and shoot and root weights have not been negatively affected by oil, compared to the control plant, up to a concentration of 1.5% for up to six months. Crude oil degradation percentages were found to be in the range of 49-79%. The highest degradation percentage was recorded for the soil collected from underneath A. sieberiana Tausch seedlings (79%). A total of 81 different hydrocarbons were detected in soil samples at zero time and most of them were found to be of long (≥30 carbon atoms) and moderate (10-29 C) hydrocarbon chains. Fraction analyses were conducted in plant A. sieberiana Tausch seedlings at intervals of 60, 120 and 180 days of incubation, six different hydrocarbons were detected. The most abundant hydrocarbon detected were Heneicosane (21 C), Tetracosane (24 C) and Octacosane (28 C). The viable microorganism's count in oil-contaminated soil at any of the concentrations tested was significantly (P ≤ 0.01) higher than that in oil-free soil at any sampling interval. High efficiency of biodegradation was achieved using A. seiberiana Tausch indicating the unique mechanism of this plant in remediating contaminated soil with crude oil.

Biofabrication of ZnO nanoparticles using Acacia arabica leaf extract and their antibiofilm and antioxidant potential against foodborne pathogens.

Emergence of multidrug resistant pathogens is increasing globally at an alarming rate with a need to discover novel and effective methods to cope infections due to these pathogens. Green nanoparticles have gained attention to be used as efficient therapeutic agents because of their safety and reliability. In the present study, we prepared zinc oxide nanoparticles (ZnO NPs) from aqueous leaf extract of Acacia arabica. The nanoparticles produced were characterized through UV-Visible spectroscopy, scanning electron microscopy, and X-ray diffraction. In vitro antibacterial susceptibility testing against foodborne pathogens was done by agar well diffusion, growth kinetics and broth microdilution assays. Effect of ZnO NPs on biofilm formation (both qualitatively and quantitatively) and exopolysaccharide (EPS) production was also determined. Antioxidant potential of green synthesized nanoparticles was detected by DPPH radical scavenging assay. The cytotoxicity studies of nanoparticles were also performed against HeLa cell lines. The results revealed that diameter of zones of inhibition against foodborne pathogens was found to be 16-30 nm, whereas the values of MIC and MBC ranged between 31.25-62.5 µg/ml. Growth kinetics revealed nanoparticles bactericidal potential after 3 hours incubation at 2 × MIC for E. coli while for S. aureus and S. enterica reached after 2 hours of incubation at 2 × MIC, 4 × MIC, and 8 × MIC. 32.5-71.0% inhibition was observed for biofilm formation. Almost 50.6-65.1% (wet weight) and 44.6-57.8% (dry weight) of EPS production was decreased after treatment with sub-inhibitory concentrations of nanoparticles. Radical scavenging potential of nanoparticles increased in a dose dependent manner and value ranged from 19.25 to 73.15%. Whereas cytotoxicity studies revealed non-toxic nature of nanoparticles at the concentrations tested. The present study suggests that green synthesized ZnO NPs can substitute chemical drugs against antibiotic resistant foodborne pathogens.

Invasion of Native Riparian Forests by Acacia Species Affects In-Stream Litter Decomposition and Associated Microbial Decomposers.

The invasion of native riparian forests by exotic tree species can lead to profound changes in the ecological integrity of freshwater ecosystems. We assessed litter decomposition of native (Alnus glutinosa and Quercus robur) and invasive (Acacia melanoxylon and Acacia dealbata) tree species, and associated microbial activity and community structure, after being immersed for conditioning in 3 reference and 3 "invaded" streams in Serra da Lousã (central Portugal) and used in microcosms simulating stream conditions. Litter decomposition differed among species, in the order: Al. glutinosa > Q. robur > (Ac. melanoxylon ~ Ac. dealbata). Alnus glutinosa litter decomposed faster probably because it was soft and had high nitrogen concentration for decomposers. Quercus robur litter decomposed slower most likely because it was tough and had high polyphenol and low nitrogen concentrations. Acacia melanoxylon litter was the toughest and had a thick cuticle that likely acted as a physical barrier for microbial colonization. In Ac. dealbata, the small-sized leaflets and high lignin concentration may have limited microbial litter decomposition. Litter decomposition was faster in "invaded" streams, probably because they were N-limited and increases in nitrogen concentration in water, promoted by Acacia species invasion, stimulated microbial activity on litter. The aquatic hyphomycete community structure differed among litter species and between stream types, further suggesting that microbes were sensitive to litter characteristics and water nutrient concentrations. Overall, the invasion of native riparian forests by Acacia species may affect microbial decomposer activity, thus altering important stream ecosystem processes, such as litter decomposition and nutrient cycles.

Synthesis of AgNPs coated with secondary metabolites of Acacia nilotica: An efficient antimicrobial and detoxification agent for environmental toxic organic pollutants.

This study concentrates on biosynthesis of Silver Nanoparticles (AgNPs) from stem extract of Acacia nilotica (A. nilotica). The reaction was completed at a temperature ~40-45 °C and time duration of 5 h. AgNPs were thoroughly investigated via advanced characterization techniques such as UV-Vis spectrophotometry (UV-Vis), Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffractometry (XRD), Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM), X-ray Photoelectron Spectroscopy (XPS), Thermo Gravimetric Analysis (TGA), Diffuse Reflectance Spectroscopy (DRS), Brunner-Emmett-Teller (BET), Dynamic Light Scattering (DLS), and Zeta potential analysis. AgNPs with average size below 50 nm were revealed by all the measuring techniques. Maximum surface area ~5.69 m2/g was reported for the as synthesized NPs with total pore volume ~0.0191 mL/g and average pore size ~1.13 nm. Physical properties such as size and shape have changed the surface plasmon resonance peak in UV-visible spectrum. Antimicrobial activity was reported due to denaturation of microbial ribosome's sulphur and phosphorus bond by silver ions against bacterium Methicillin Resistant Staphylococcus aureus (MRSA) and fungus Candida Albican (CA). Furthermore, AgNPs degraded toxic pollutants such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP) and various hazardous dyes such as Congo Red (CR), Methylene Blue (MB) and Methyl Orange (MO) up to 95%. The present work provided low cost, green and an effective way for synthesis of AgNPs which were utilized as potential antimicrobial agents as well as effective catalyst for detoxification of various pollutants and dyes.

Rhizosphere modifications of iron-rich minerals and forms of heavy metals encapsulated in sulfidic tailings hardpan.

Hardpan caps formed after extensive weathering of the top layer of sulfidic tailings have been advocated to serve as physical barriers separating reactive tailings in depth and root zones above. However, in a hardpan-based root zone reconstructed with the soil cover, roots growing into contact with hardpan surfaces may induce the transformation of Fe-rich minerals and release potentially toxic elements for plant uptake. For evaluating this potential risk, two representative native species, Turpentine bush (Acacia chisholmii, AC) and Red Flinders grass (Iseilema vaginiflorum, RF), of which pre-cultured root mats were interfaced with thin discs of crushed hardpan minerals in the rhizosphere (RHIZO) test. After 35 days, the surface dissolution of hardpan minerals occurred and Fe-rich cement minerals were transformed from ferrihydrite-like minerals to goethite-like and Fe(III)-carboxylic complexes, as revealed by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and synchrotron-based X-ray absorption fine structure spectroscopy (XAFS) analysis. This transformation may result from the functions of root exudates. The transformation of hardpan cement minerals caused the co-dissolution of Cu and Zn initially encapsulated in the cements and their uptake by plants. Nevertheless, only was the minority of the plant Cu and Zn transported into shoots.

Pea protein isolate-gum Arabic Maillard conjugates improves physical and oxidative stability of oil-in-water emulsions.

The present work investigated the impact of incubation time (0, 1, 3, and 5 day) on the properties and functionalities of conjugates formed between pea protein isolate (PPI) and gum Arabic (GA). The participation of both 11S and 7S to form conjugates with GA was proved by SDS-PAGE. The degree of conjugation reaction of conjugated was characterized by measuring the formation of Maillard reaction products, the loss of free amino groups, and color changes. The results suggested that PPI intimately incorporated into GA after 1 day incubation, giving a non-homogeneous microstructure with a reduction of nearly 18% available free amino and an increase of relative solubility to 15.5%. Additionally, emulsions prepared by PPI-GA conjugates showed smaller particle size, higher surface charge, and stronger steric hindrance to stabilize the emulsion droplets against environmental stresses and lipid oxidation. The findings provide a practical means to improve the functionality of pea proteins.

Discrimination of geographical origins of Chinese acacia honey using complex 13C/12C, oligosaccharides and polyphenols.

The aim of this study was to predict the geographical origin of acacia honey of China through analysis of physicochemical parameters combination with chemometrics. Samples from six different origins were investigated on parameters of δ13C value, oligosaccharides and polyphenols, using EA-IRMS/LC-IRMS, GC-MS and HPLC-MS, respectively. The results indicated that the δ13C value of honey from Gansu region were lower than those of other regions. Oligosaccharides of honey from Shanxi and Shaanxi regions were both higher than other four regions. Polyphenols of honey from Shandong region was the highest and were better parameters than both δ13C and oligosaccharides in discrimination of geographical origins. Partial Least Square Discriminant Analysis (PLS-DA) showed that when all 31 different parameters were combined, a correct classification rate of 94.12% could be achieved using external cross validation method. In conclusion, the method in discrimination of geographical can be used to provide reliable and useful reference information.

Novel bioactive peptides demonstrating anti-dengue virus activity isolated from the Asian medicinal plant Acacia Catechu.

The therapeutic activities of food-derived bioactive proteins and peptides are attracting increased attention within the research community. Medicinal plants used in traditional medicines are an excellent source of bioactive proteins and peptides, especially those traditionally prepared by water extraction for use as tea or food supplement. In this study, novel bioactive peptides were isolated from enzymatic digests of 33 Thai medicinal plants. The inhibitory activity of each against dengue virus (DENV) infection was investigated. Of 33 plants, peptides from Acacia catechu extract demonstrated the most pronounced anti-DENV activity. Half maximal inhibitory concentration of 0.18 µg/ml effectively inhibited DENV foci formation. Treatment with 1.25 µg/ml crude peptide extract could reduce virus production less than 100-fold with no observable cell toxicity. Peptide sequences were determined by high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry. Two bioactive peptides isolated from Acacia catechu inhibited DENV foci formation >90% at the concentration of 50 µM; therefore, they are recommended for further investigation as antiviral peptides against DENV infection.

Coordination between leaf, stem, and root hydraulics and gas exchange in three arid-zone angiosperms during severe drought and recovery.

The ability to resist hydraulic dysfunction in leaves, stems, and roots strongly influences whether plants survive and recover from drought. However, the coordination of hydraulic function among different organs within species and their links to gas exchange during drought and recovery remains understudied. Here, we examine the interaction between gas exchange and hydraulic function in the leaves, stems, and roots of three semiarid evergreen species exposed to a cycle of severe water stress (associated with substantial cavitation) and recovery. In all species, stomatal closure occurred at water potentials well before 50% loss of stem hydraulic conductance, while in two species, leaves and/or roots were more vulnerable than stems. Following soil rewetting, leaf-level photosynthesis (Anet ) returned to prestress levels within 2-4 weeks, whereas stomatal conductance and canopy transpiration were slower to recover. The recovery of Anet was decoupled from the recovery of leaf, stem, and root hydraulics, which remained impaired throughout the recovery period. Our results suggest that in addition to high embolism resistance, early stomatal closure and hydraulic vulnerability segmentation confers drought tolerance in these arid zone species. The lack of substantial embolism refilling within all major organs suggests that vulnerability of the vascular system to drought-induced dysfunction is a defining trait for predicting postdrought recovery.

Regulatory roles of 24-epibrassinolide in tolerance of Acacia gerrardii Benth to salt stress.

This experiment aimed to investigate the role of 24-epibrassinolide (EBL) against NaCl-induced salinity stress in Acacia gerrardii Benth. NaCl (200 mM) imparted deleterious effects on the growth and chlorophyll contents of A. gerrardii, but foliar application of EBL (1.0 mg/l; each plant received 2.5 ml) mitigated the negative effect considerably. NaCl reduced chlorophyll content but this was significantly ameliorated by the application of EBL. EBL reduced significantly NaCl-induced oxidative stress hence protect membranes and also improved the relative water content significantly by 6.6% as compared with control. Nitrate reductase activity declined after NaCl treatment but EBL application sustained its activity under normal and stressed conditions. Exogenous application of EBL significantly improved the activity of superoxide dismutase, catalase and the enzymes of the ascorbate-glutathione pathway thereby protecting the photosynthetic electron transport chain and other metabolic processes in A. gerrardii from NaCl-induced oxidative stress.

The concentration of ascorbic acid and glutathione in 13 provenances of Acacia melanoxylon.

Climate change can negatively affect sensitive tree species, affecting their acclimation and adaptation strategies. A common garden experiment provides an opportunity to test whether responses of trees from different provenances are genetically driven and if this response is related to factors at the site of origin. We hypothesized that antioxidative defence systems and leaf mass area ofAcacia melanoxylonR. Br. samples collected from different provenances will vary depending on local rainfall. Thirteen provenances ofA. melanoxylonoriginating from different rainfall habitats (500-2000 mm) were grown for 5 years in a common garden. For 2 years, phyllode samples were collected during winter and summer, for measurements of leaf mass area and concentrations of glutathione and ascorbic acid. Leaf mass area varied between seasons, years and provenances ofA. melanoxylon, and an increase was associated with decreasing rainfall at the site of origin. Ascorbic acid and glutathione concentrations varied between seasons, years (i.e., environmental factors) and among provenances ofA. melanoxylon In general, glutathione and ascorbic acid concentrations were higher in winter compared with summer. Ascorbic acid and glutathione were different among provenances, but this was not associated with rainfall at the site of origin.

The effects of acacia honey on in vitro corneal abrasion wound healing model.

BACKGROUND: Acacia honey (AH) has been proven to improve skin wound healing, but its therapeutic effects on corneal epithelium has not been elucidated to date. This study aimed to investigate the effects of AH on cultured corneal epithelial cells (CEC) on in vitro corneal abrasion wound healing model. Six New Zealand white rabbits' CEC were isolated and cultured until passage 1. Circular wound area was created onto a confluent monolayer CEC using a corneal trephine which mimicked corneal abrasion and treated with 0.025% AH supplemented in basal medium (BM) and complete cornea medium (CCM). Wound healing was measured as the percentage of wound closure by the migration of CEC on day 0, day 3 and day 6, post wound creation. The morphological changes of CEC were assessed via phase contrast microscopy. Gene and protein expressions of cytokeratin (CK3), fibronectin and cluster of differentiation 44 (CD44) in AH treated groups and control groups were determined by real-time PCR and immunocytochemistry, respectively. RESULTS: Cultured CEC exhibited similar morphology of polygonal shaped cells in all culture media. CEC cultured in AH-supplemented media showed higher percentage of wound closure compared to the controls. Gene expression of CK3 increased in AH-supplemented groups throughout the study. Fibronectin expression was increased at the initial stage while CD44 expression was increased at day 3, post wound creation. The protein expression of CEC cultured in all media was in accordance to their respective gene expressions. CONCLUSION: Supplementation of AH in BM and CCM media accelerates CEC wound closure of the in vitro corneal abrasion model by increasing the expression of genes and proteins associated with CEC wound healing.

Isolation and characterization of CCoAOMT in interspecific hybrid of Acacia auriculiformis x Acacia mangium--a key gene in lignin biosynthesis.

This study was directed at the understanding of the function of CCoAOMT isolated from Acacia auriculiformis x Acacia mangium. Full length cDNA of the Acacia hybrid CCoAOMT (AhCCoAOMT) was 1024-bp long, containing 750-bp coding regions, with one major open reading frame of 249 amino acids. On the other hand, full length genomic sequence of the CCoAOMT (AhgflCCoAOMT) was 2548 bp long, containing three introns and four exons with a 5' untranslated region (5'UTR) of 391 bp in length. The 5'UTR of the characterized CCoAOMT gene contains various regulatory elements. Southern analysis revealed that the Acacia hybrid has more than three copies of the CCoAOMT gene. Real-time PCR showed that this gene was expressed in root, inner bark, leaf, flower and seed pod of the Acacia hybrid. Downregulation of the homologous CCoAOMT gene in tobacco by antisense (AS) and intron-containing hairpin (IHP) constructs containing partial AhCCoAOMT led to reduction in lignin content. Expression of the CCoAOMT in AS line (pART-HAS78-03) and IHP line (pART-HIHP78-06) was reduced respectively by 37 and 75% compared to the control, resulting in a decrease in the estimated lignin content by 24 and 56%, respectively. AhCCoAOMT was found to have altered not only S and G units but also total lignin content, which is of economic value to the pulp industry. Subsequent polymorphism analysis of this gene across eight different genetic backgrounds each of A. mangium and A. auriculiformis revealed 47 single nucleotide polymorphisms (SNPs) in A. auriculiformis CCoAOMT and 30 SNPs in A. mangium CCoAOMT.

Effects of season, browse species and polyethylene glycol addition on gas production kinetics of forages in the subhumid subtropical savannah, South Africa.

BACKGROUND: This study was conducted to investigate the effects of season, species and polyethylene glycol addition on gas production (GP) and GP kinetic parameters by in vitro incubation (72 h) of five plant species from the subhumid subtropical savannah, South Africa. Plant species used were Acacia natalitia, Acacia nilotica, Dichrostachys cinerea, Scutia myrtina and Chromolaena odorata, leaves of which were harvested during the dry (June/July), early wet (November/December) and late wet (February/March) seasons. An automated in vitro gas production technique was used in two experiments carried out with nine replicates. The first experiment was to test the effect of season and species, while the second experiment tested the effect of tannins using polyethylene glycol 4000 (PEG). The PEG treatment was applied to samples in the early wet and late wet seasons. RESULTS: There were wide variations among seasons and species in crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and condensed tannin (CT). Season and species affected the maximum GP and GP kinetic parameters. During the three seasons, C. odorata had the highest CP (186-226 g kg(-1) dry matter (DM)) and GP (87-104 mL g(-1) DM) and S. myrtina had the lowest CP (105-129 g kg(-1) DM), while A. nilotica, A. natalitia, D. cinerea and S. myrtina had similar and low GP (23-50 mL g(-1) DM). The maximum GP, its degradation rate and GP from the soluble fraction were positively correlated with CP both without and with PEG. With PEG, GP from the soluble fraction was negatively correlated with NDF, ADL and CT; without PEG, it was negatively correlated with CT. CONCLUSION: Both season and species affected the GP parameters. The addition of PEG emphasises that the inhibitory effect of tannins on rumen microbes was greater for all but C. odorata, confirming that these browse species can be used as feed supplements.

Responses to water stress of gas exchange and metabolites in Eucalyptus and Acacia spp.

Studies of water stress commonly examine either gas exchange or leaf metabolites, and many fail to quantify the concentration of CO2 in the chloroplasts (C(c)). We redress these limitations by quantifying C(c) from discrimination against ¹³CO2 and using gas chromatography-mass spectrometry (GC-MS) for leaf metabolite profiling. Five Eucalyptus and two Acacia species from semi-arid to mesic habitats were subjected to a 2 month water stress treatment (Ψ(pre-dawn) = -1.7 to -2.3 MPa). Carbohydrates dominated the leaf metabolite profiles of species from dry areas, whereas organic acids dominated the metabolite profiles of species from wet areas. Water stress caused large decreases in photosynthesis and C(c), increases in 17-33 metabolites and decreases in 0-9 metabolites. In most species, fructose, glucose and sucrose made major contributions to osmotic adjustment. In Acacia, significant osmotic adjustment was also caused by increases in pinitol, pipecolic acid and trans-4-hydroxypipecolic acid. There were also increases in low-abundance metabolites (e.g. proline and erythritol), and metabolites that are indicative of stress-induced changes in metabolism [e.g. γ-aminobutyric acid (GABA) shunt, photorespiration, phenylpropanoid pathway]. The response of gas exchange to water stress and rewatering is rather consistent among species originating from mesic to semi-arid habitats, and the general response of metabolites to water stress is rather similar, although the specific metabolites involved may vary.