Competitive inhibition of the auxin-induced elongation by α-D-oligogalacturonides in pea stem segments

Branca, C, De Lorenzo, G. and Cervone, F. 1988. Competitive inhibition of the auxin-induced elongation by α-D-oligogalacturonides in pea stem segments. - Physiol. Plant. 72: 499–504.
α-D-galacturonide oligomers (OG) were prepared by partial hydrolysis of sodium polypectate with an homogeneous Aspergillus niger endopolygalacturonase (EC 3.2.1.15). OG, obtained after digestion for 10, 20, 30, 60, 120 min and 24 h, were assayed for their ability to interfere with the IAA-induced elongation of pea ( Pisum sativum L. cv. Alaska) stems. Maximum inhibiting activity was exhibited by oligomers with an approximate degree of polymerization higher than 8. Inhibition by longer OG was much lower, and the products of the 24 h digestion and the unhydrolysed polypectate were ineffective. The addition of OG to pea stems caused a parallel shift to the right of the IAA dose-effect curve. The shift depended on the amount of OG used, showing that oligogalacturonides behave as competitive antagonists of IAA. The presence of OG caused the disappearance of the second maximum of the elongation rate and reduced the first maximum. OG were also tested for their ability to inhibit IAA-induced ethylene evolution of pea stem segments. Maximal inhibition was obtained with OG of the same size as those that interfered with IAA-induced elongation. Inhibition of the auxin action seemed to be specific as OG did not interfere with the activity of gibberellic acid (GA₃) or kinetin. It was concluded that oligogalacturonides strongly interfere with the activity of IAA, although they are by themselves incapable to influence the elongation of pea stem segments directly.     

In vitro morphophysiological responses of Alternanthera tenella colla (Amaranthaceae) to stress induced by cadmium and the attenuating action of silicon

Plant Cell, Tissue and Organ Culture (PCTOC) - Despite having the ability to bioaccumulate trace elements such as cadmium (Cd), many species also present morphophysiological disorders that can...     

Synthesis,biological evaluation and molecular modeling of novel selective COX-2 inhibitors: sulfide,sulfoxide, and sulfone derivatives of 1,5-diarylpyrrol-3-substituted scaffold

A novel series of 1,5-diarylpyrrol-3-sulfur derivatives (10–12) was synthesized and characterized by NMR and mass spectroscopy and x-ray diffraction. The biological activity of these compounds was evaluated in in vitro and in vivo tests to assess their COX-2 inhibitory activity along with anti-inflammatory and antinociceptive effect.Results showed that the bioisosteric transformation of previously reported alkoxyethyl ethers (9a-c) into the corresponding alkyl thioethers (10a-c) still leads to selective and active compounds being the COX-2 inhibitory activity for most of them in the low nanomolar range. The oxidation products of 10a,b were also investigated and both couple of sulfoxides (11a,b) and sulfones (12a,b) showed an appreciable COX-2 inhibitory activity. Molecular modeling studies were performed to investigate the binding mode of the representative compounds 10b, 11b, and 12b into COX-2 enzyme and to explore the potential site of metabolism of 10a and 10b due to the different in vivo efficacy. Among the developed compounds, compound 10b showed a significant in vivo anti-inflammatory and antinociceptive activity paving the way to develop novel anti-inflammatory drugs.     

Defining freshwater as a natural resource: a framework linking water use to the area of protection natural resources

The International Journal of Life Cycle Assessment - While many examples have shown unsustainable use of freshwater resources, existing LCIA methods for water use do not comprehensively address...     

Solution structure and biochemical characterization of a spare part protein that restores activity to an oxygen-damaged glycyl radical enzyme

JBIC Journal of Biological Inorganic Chemistry - Glycyl radical enzymes (GREs) utilize a glycyl radical cofactor to carry out a diverse array of chemically challenging enzymatic reactions in...     

An Arabidopsis berberine bridge enzyme‐like protein specifically oxidizes cellulose oligomers and plays a role in immunity

The plant cell wall is the barrier that pathogens must overcome to cause a disease, and to this end they secrete enzymes that degrade the various cell wall components. Due to the complexity of these components, several types of oligosaccharide fragments may be released during pathogenesis and some of these can act as damage‐associated molecular patterns (DAMPs). Well‐known DAMPs are the oligogalacturonides (OGs) released upon degradation of homogalacturonan and the products of cellulose breakdown, i.e. the cellodextrins (CDs). We have previously reported that four Arabidopsis berberine bridge enzyme‐like (BBE‐like) proteins (OGOX1–4) oxidize OGs and impair their elicitor activity. We show here that another Arabidopsis BBE‐like protein, which is expressed coordinately with OGOX1 during immunity, specifically oxidizes CDs with a preference for cellotriose (CD3) and longer fragments (CD4–CD6). Oxidized CDs show a negligible elicitor activity and are less easily utilized as a carbon source by the fungus Botrytis cinerea. The enzyme, named CELLOX (cellodextrin oxidase), is encoded by the gene At4 g20860. Plants overexpressing CELLOX display an enhanced resistance to B. cinerea, probably because oxidized CDs are a less valuable carbon source. Thus, the capacity to oxidize and impair the biological activity of cell wall‐derived oligosaccharides seems to be a general trait of the family of BBE‐like proteins, which may serve to homeostatically control the level of DAMPs to prevent their hyperaccumulation.     

Estimating the Material Stock of Roads: The Vietnamese Case Study

This study is a pioneering effort to quantify the materials stocked in the road network of a developing country, Vietnam, and analyze its relationships to the country's recent economic development. National road networks function as capital and infrastructure investments that are necessary catalysts for countries’ development, while requiring the extraction of vast amounts of construction materials for expansion and maintenance causing environmental impacts. However, there has so far been little research on the subject, especially in developing countries. We compile material stock and flow accounts for Vietnam's roads from 2003 to 2013 on the national and provincial levels, finding that approximately 40% of the domestic consumption of construction materials is for expanding and maintaining the road network, and the materials stocked in the road network doubled from 1,321 million metric tons in 2003 to 2,660 million metric tons in 2012. Material stock growth rates closely resembled those of gross domestic product (GDP) in this period, suggesting a codependency of physical infrastructure development and economic development. On the provincial level, our results show local disparities in the stock and its capacity to support the transportation of passengers and freight, especially considering the surging growth of vehicles in urban centers. By showcasing the challenges of conducting a material flow and stock analysis in a developing country, this study not only sheds light on Vietnam's transportation material stock and its policy implications, but also serves as a case study for further work in similar countries.