Enhancing photosynthesis and root development for better fruit quality, aroma, and lessening of radioactive materials in key lime (Citrus aurantifolia) using Trichoderma harzianum and Bacillus thuringiensis.

The present study was conducted to investigate the effects of Trichoderma harzianum and Bacillus thuringiensis alone or with gradual levels of NPK on photosynthesis, growth, fruit quality, aroma improvement and reduced radionuclides of key lime fruits. The lemon seedlings were treated with (T0) without fertilizers as control, (T1) 100g of NPK at 100%, (T2) 5 g of Trichoderma. harzianum at 50% + 50 g of NPK at 50%, (T3) 5 g of Bacillus thuringiensis at 50% + 50 g of NPK at 50 %, (T4) 7.5 g of Trichoderma harzianum at 75% + 25 g of NPK at 25 %, (T5) 7.5 g of Bacillus thuringiensis at 75% + 25 g of NPK at 25 %, (T6) 10 g of Trichoderma harzianum at 100 % and (T7)10 g of Bacillus thuringiensis at 100 %. The results showed that T2 increased net photosynthetic rate, stomatal conductance, transpiration rate, internal CO2 concentration, fresh and dry root biomass by 209%, 74%, 56%, 376%, 69.4% and 71.6%, while, T5 increased root volume, root length, and root tip number by 27.1%, 167%, and 67%, respectively over the control trees. The microbial treatments developed cortex, vascular cylinder and tracheal elements of the root. Fruit number, length, diameter, weight, pulp thickness, pulp/peel ratio, juice, total soluble solids (TSS), pigment contents and antioxidant activity increased significantly in the T2 treatment. Vitamin C, total phenols, total flavonoids, and total sugar content increased by 1.59-, 1.66-, 1.44- and 2.07- fold in T5 treated fruits compared to the control. The two microbes increased volatile compounds and decreased radionucleotides in the fruit, moreover, 27 identified and 2 (two) unmatched volatile compounds were identified by GCMS analysis. It is concluded that T. harzianum and B. thuringiensis with 25-50 g NPK treatments improved photosynthesis, root structure, fruit growth, fruit quality, aroma and lessened radionuclides in key lime fruits.

Enhancing Rubisco gene expression and metabolites accumulation for better plant growth in Ficus deltoidea under drought stress using hydrogen peroxide.

Growth improvement of the medicinal plant, Ficus deltoidea (Mas Cotek) under drought conditions is a vital issue in Malaysia since it is a slow-growing plant and disposed to leaf damage under the stresses of drought. Therefore, investigation was done to examine the outcomes of hydrogen peroxide (H2O2) application on Rubisco gene expression and metabolites accumulation of stressed F. deltoidea plants, and thereby to record the changes in leaf histology, photosynthesis, biochemical properties, and the growth of the plant. H2O2 at the rates of 0, 5, 10, 15, and 20 mM were foliar sprayed biweekly on the drought stressed plants using a hand sprayer. The application of 20 mM H2O2 amplified leaf number, tallness, stomatal conductance, and photosynthetic yield by 143, 24, 88, and 18%, respectively, over the control plant. A reduced transpiration rate and improved chlorophyll fluorescence were also noted in H2O2-treated plants. The treatment produced a greater amount of chlorophyll a, total phenols, total flavonoids, sugar content, and antioxidant activities by 1.61-, 1.30-, 1.98-, 1.92-, and 1.53-fold, respectively. Application of 15 mM H2O2 enhanced net photosynthetic rate and internal CO2 concentrations by 1.05- and 1.25-fold, respectively. Additionally, H2O2 treatments promoted stomatal closure, increased stomata size, the number of stomata, improved vein structure, and reduced the damage of the leaf margin and mesophyll cells of drought stressed plants. The application of H2O2 also accumulated significantly higher contents of sodium (Na+), calcium (Ca2+), potassium (K+), magnesium (Mg+), and iron (Fe2+) in stressed plants. Although the amount of Arsenic (As+) and Antimony (Sb3+) increased to some extent, the increases were not at a toxic level. The use of H2O2 enhanced the Rubisco gene expression to a greater level and the ratio of Rubisco expression increased up to 16-fold. Finally, thirteen (13) identified and five (5) unmatched volatile compounds with a quality score above 70% were identified by gas chromatography-mass spectrometry (GCMS). The GCMS analysis showed that the foliar application of H2O2 accumulates a higher percentage of volatile components in plants which helps to mitigate the negative effects of drought stress. It is concluded that under drought stressed conditions the F. deltoidea plants should be treated with 10-15 mM of H2O2 twice a week to improve leaf histology, photosynthesis, the level of Rubisco gene expression and volatile compounds accumulation, and plant growth and development.

Polysaccharides from lichen Xanthoria parietina: 1,4/1,6-α-d-glucans and a highly branched galactomannan with macrophage stimulating activity via Dectin-2 activation.

Hot-water soluble polysaccharides H-1-3 and H-2-1 were isolated from the thalli of the lichen Xanthoria parietina (L.) Th. Fr. and purified by ion exchange and gel permeation chromatography. Structure elucidation was mainly based on 2D-NMR and nano-ESI-Q-TOF MS/MS experiments. H-1-3 (13.7 kDa) was shown to be linear α-glucan with α-d-Glcp-(1 → [→[4)-α-d-Glcp-(1]2 → [6)-α-d-Glcp-(1]3 → 4)]n core backbone. The (1,4)- and (1,6)-α-d-Glcp linkages were in a 2:3 M ratio. H-2-1 (525 kDa) was characterized as a complex branched ß-galacto-α-mannan with →[6)-α-d-Manp-(1 → [2,6)-α-d-Manp-(1]2 → [2)-α-d-Manp-(1]2→]n core units and main side chains of (1,3)-ß-d-Galf linked at O-6 to →2)-α-d-Manp-(1→, together with minor terminal units of 1,4/1,6-α-D -Glcp units attached to the core chain at O-6 position and α-L-Rhap linked to Galf side chain at O-2 position (Manp: Galf: Glcp: Rhap linkage ratio = 9:3:2:1). H-2-1 exerted strong immunoactivity in vitro and activated murine RAW macrophages 264.7 towards significantly increased phagocytosis, TNF-α and IL-1ß secretion. These effects are due to an interaction of the galactomannan with the transmembrane pattern-recognition protein Dectin-2 of the macrophages.

Cytotoxic aaptamines from Malaysian Aaptos aaptos.

In a preliminary screen, Aaptos aaptos showed significant cytotoxic activity towards a panel of cell lines and was thus subjected to bioassay-guided isolation of the bioactive constituents. In addition to the known aaptamine, two new derivatives of the alkaloid were isolated from the bioactive chloroform fraction of the crude methanolic extract. Detailed analysis by NMR and mass spectroscopy enabled their identification to be 3-(phenethylamino)demethyl(oxy)aaptamine and 3-(isopentylamino)demethyl(oxy) aaptamine. The cytotoxic activities of the three alkaloids were further evaluated against CEM-SS cells.

Isolation of a sulphated polysaccharide from a recently discovered sponge species (Celtodoryx girardae) and determination of its anti-herpetic activity.

Exopolysaccharides (EPS) were extracted from a sponge, Celtodoryx girardae recently discovered in the Golfe du Morbihan in 2000. Sponge samples were collected monthly from November 2007 to May 2008. SEC analysis of EPS samples showed that they exhibit a unique molecular weight of approximately 800 kDa. However, infrared analysis revealed that structural seasonal variations occur. EPS fractions also exhibit significant sulphate contents and were screened in vitro for a potential antiviral activity against Herpes simplex virus type 1 (HSV-1). The best result was obtained with a sample collected in January which exhibits an EC(50) of 5.9 microg/mL without cytotoxicity on the Vero cell line. Experiments carried out to elucidate the mechanism of the EPS showed that the sulphated groups of EPS interact with the glycoproteins on the surface of the virus' membrane.