Allelopathy and its coevolutionary implications between native and non‐native neighbors of invasive Cynara cardunculus L.

Invasive plants apply new selection pressures on neighbor plant species by different means including allelopathy. Recent evidence shows allelopathy functions as remarkably influential mediator for invaders to be successful in their invaded range. However, few studies have determined whether native and non‐native species co‐occurring with invaders have evolved tolerance to allelopathy. In this study, we conducted germination and growth experiments to evaluate whether co‐occurring native Juncus pallidus and non‐native Lolium rigidum species may evolve tolerance to the allelochemicals induced by Cyanara cardunculus in Australian agricultural fields. The test species were germinated and grown in pots filled with collected invaded and uninvaded rhizosphere soil of C. cardunculus with and without activated carbon (AC). Additionally, a separate experiment was done to differentiate the direct effects of AC on the test species. The soil properties showed invaded rhizosphere soils had higher total phenolic and lower pH compared with uninvaded soils. We found significant reduction of germination percentage and seedling growth in terms of above‐ and belowground biomass, and maximum plant height and root length of native in the invaded rhizosphere soil of C. cardunculus, but little effect on non‐native grass species. Even soil manipulated with AC showed no significant differences in the measured parameters of non‐native except aboveground biomass. Taken together, the results indicate allelochemicals induced by C. cardunculus exert more suppressive effects on native than non‐native linking the coevolved tolerance of those.     

Identification and Phytotoxicity Assessment of Phenolic Compounds in Chrysanthemoides monilifera subsp. monilifera (Boneseed)

Chrysanthemoides monilifera subsp. monilifera (boneseed), a weed of national significance in Australia, threatens indigenous species and crop production through allelopathy. We aimed to identify phenolic compounds produced by boneseed and to assess their phytotoxicity on native species. Phenolic compounds in water and methanol extracts, and in decomposed litter-mediated soil leachate were identified using HPLC, and phytotoxicity of identified phenolics was assessed (repeatedly) through a standard germination bioassay on native Isotoma axillaris. The impact of boneseed litter on native Xerochrysum bracteatum was evaluated using field soil in a greenhouse. Collectively, we found the highest quantity of phenolic compounds in boneseed litter followed by leaf, root and stem. Quantity varied with extraction media. The rank of phenolics concentration in boneseed was in the order of ferulic acid > phloridzin > catechin > p-coumaric acid and they inhibited germination of I. axillaris with the rank of ferulic acid > catechin > phloridzin > p-coumaric acid. Synergistic effects were more severe compared to individual phenolics. The litter-mediated soil leachate (collected after15 days) exhibited strong phytotoxicity to I. axillaris despite the level of phenolic compounds in the decomposed leachate being decreased significantly compared with their initial level. This suggests the presence of other unidentified allelochemicals that individually or synergistically contributed to the phytotoxicity. Further, the dose response phytotoxic impacts exhibited by the boneseed litter-mediated soil to native X. bracteatum in a more naturalistic greenhouse experiment might ensure the potential allelopathy of other chemical compounds in the boneseed invasion. The reduction of leaf relative water content and chlorophyll level in X. bracteatum suggest possible mechanisms underpinning plant growth inhibition caused by boneseed litter allelopathy. The presence of a substantial quantity of free proline in the target species also suggests that the plant was in a stressed condition due to litter allelopathy. These findings are important for better understanding the invasive potential of boneseed and in devising control strategies.     

Phorbol ester-induced shedding of the prostate cancer marker transmembrane protein with epidermal growth factor and two follistatin motifs 2 is mediated by the disintegrin and metalloproteinase-17

The transmembrane protein with epidermal growth factor and two follistatin motifs 2 (TMEFF2) is expressed in prostate and brain and shed from the cell surface in a metalloproteinase-dependent fashion. Neither the sheddase(s) responsible for TMEFF2 shedding nor the physiological significance or activity of the soluble TMEFF2 ectodomain (TMEFF2-ECD) has been identified. In the present study we present new evidence that a disintegrin and metalloproteinase-17 (ADAM17) is responsible for phorbol 12-myristate 13-acetate-induced release of TMEFF2-ECD using small interfering RNA to ablate ADAM17 expression or by inhibiting enzymatic activity. A single well shedding assay monitoring the release of alkaline phosphatase-tagged TMEFF2-ECD into medium and the generation of 22- and 14-kDa C-terminal fragments in lysates were dependent on ADAM17 activity. A gamma-secretase inhibitor prevented the formation of a 10-kDa fragment in cell lysates, thus establishing TMEFF2 as a novel substrate for regulated intramembrane proteolysis. We assigned proliferation-inducing activity to TMEFF2. Inhibition of TMEFF2 shedding using synthetic metalloproteinase inhibitors or small interfering RNA targeting TMEFF2 expression yielded a statistically significant reduction of cell proliferation in the lymph node-derived prostate cancer cells (LNCaPs) and a human embryonic kidney (HEK293) cell line overexpressing TMEFF2. The TMEFF2-ECD was able to induce ERK1/2 phosphorylation in an epidermal growth factor receptor (or ErbB1)-dependent manner in HEK293 cells. Our data suggest that TMEFF2 contributes to cell proliferation in an ADAM17-dependent autocrine fashion in cells expressing this protein.     

Potential for hydrogen and methane production from biomass residues in Canada

Canada generates approximately 1.45 x 10(8)t of residual biomass per year, containing an estimated energy value of 2.28 x 10(9)GJ, which is equivalent to about 22% of Canada's current annual energy use. Anaerobic digestion of these biomass residues using conventional technologies could generate 1.14 x 10(10)m(3)/year of CH(4) with a heating value of 4.56 x 10(8)GJ. Conversion of these residues using emerging technologies that favor the synthesis of H(2) and represses the synthesis of CH(4) could generate 1.47 x 10(10)m(3)/year renewable H(2), with a heating value of 1.89 x 10(8)GJ. While CH(4)-production results in a larger amount of energy recovery, generating H(2) from waste biomass is a renewable alternative that could fuel the hydrogen economy. Additional research to further both the technical and commercial development of microbial bio-energy from biomass is warranted.     

Effects of different levels of wheat bran, rice bran and maize powder supplementation with saw dust on the production of shiitake mushroom (Lentinus edodes (Berk.) Singer)

The cultivation of shiitake mushroom (Lentinus edodes) is increasing rapidly in Bangladesh due to its nutritional and medicinal importance with excellent flavor and longer shelf life. With the aim of increased production, we have cultivated L. edodes on saw dust (SD) supplemented with different levels (10%, 15%, 20%, 25%, 30%, 35% and 40%) of wheat bran (WB), rice bran (RB), maize powder (MP) and their combination (WB+RB+MP = 1:1:1) to investigate the growth, yield and quality of this mushroom. Most of the growth, yield and quality parameters varied significantly when mushrooms were cultivated with different levels of supplementation. The yield of mushroom was increased with the level of each supplementation upto a certain level, and then decreased. SD supplemented with 25% WB produced the highest number of fruiting bodies (34.8/500 g packet), highest biological yield (153.3/500 g packet), and biological efficiency (76.6%) of L. edodes. But the yield of the best quality mushroom was observed on SD with 40% WB supplementation; however, the qualities were not always supplementation dose dependent. In this study, we report that 25% WB supplementation with SD may be very effective for higher yield and 40% WB supplementation for better quality of L. edodes.     

Arginine methylation regulates DNA polymerase beta

Alterations in DNA repair lead to genomic instability and higher risk of cancer. DNA base excision repair (BER) corrects damaged bases, apurinic sites, and single-strand DNA breaks. Here, a regulatory mechanism for DNA polymerase beta (Pol beta) is described. Pol beta was found to form a complex with the protein arginine methyltransferase 6 (PRMT6) and was specifically methylated in vitro and in vivo. Methylation of Pol beta by PRMT6 strongly stimulated DNA polymerase activity by enhancing DNA binding and processivity, while single nucleotide insertion and dRP-lyase activity were not affected. Two residues, R83 and R152, were identified in Pol beta as the sites of methylation by PRMT6. Genetic complementation of Pol beta knockout cells with R83/152K mutant revealed the importance of these residues for the cellular resistance to DNA alkylating agent. Based on our findings, we propose that PRMT6 plays a role as a regulator of BER.     

Kinetics of medium-chain-length polyhydroxyalkanoate production by a novel isolate of Pseudomonas putida LS46

Six bacteria that synthesize medium-chain-length polyhydroxyalkanoates (mcl-PHAs) were isolated from sewage sludge and hog barn wash and identified as strains of Pseudomonas and Comamonas by 16S rDNA gene sequencing. One isolate, Pseudomonas putida LS46, showed good PHA production (22% of cell dry mass) in glucose medium, and it was selected for further studies. While it is closely related to other P.?putida strains (F1, KT2440, BIRD-1, GB-1, S16, and W619), P.?putida LS46 was genetically distinct from these other strains on the basis of nucleotide sequence analysis of the cpn60 gene hypervariable region. PHA production was detected as early as 12?h in both nitrogen-limited and nitrogen-excess conditions. The increase in PHA production after 48?h was higher in nitrogen-limited cultures than in nitrogen-excess cultures. Pseudomonas?putida LS46 produced mcl-PHAs when cultured with glucose, glycerol, or C(6)-C(14) saturated fatty acids as carbon sources, and mcl-PHAs accounted for 56% of the cell dry mass when cells were batch cultured in medium containing 20?mmol/L octanoate. Although 3-hydroxydecanoate was the major mcl-PHA monomer (58.1-68.8?mol%) in P.?putida LS46 cultured in glucose medium, 3-hydroxyoctanoate was the major monomer produced in octanoate medium (88?mol%).