Nematicidal Principles from Two Species of Lamiaceae

Aqueous extracts of Ocimum sanctum and O. basilicum leaves contained compounds that killed Meloidogyne incognita larvae in 160 min. Thin layer and gas-liquid chromatography, and infrared spectrophotometry indicated that the essential oils eugenol and linalool were the active nematicidal compounds.     

Changes in litter decomposition and soil organic carbon in a reforested tropical deciduous cover (India)

Soil organic carbon (SOC) up to 1 m depth originates from contemporary vegetation cover dating from past millennia. Deforestation and reforestation with economically important species is influencing soil carbon sequestration. An attempt has been made in this study to evaluate the impact of vegetation cover change (due to replacement of natural heterogeneous cover by teak and bamboo) on SOC using carbon isotopes (δ¹³C, ¹⁴C) in a tropical system (India). A litter decomposition study was carried out to understand the impact of differences in vegetation characteristics (specifically of leaves) on decomposition. Both experiments were carried out to look at the impact of changes in vegetation characteristics (specifically of leaves) on litter decomposition, and how these influence near term litter decomposition rates (k values) and long-term SOC content of the soil system beneath. Leaves of teak, bamboo and eight other species were selected for this study. The proportion of structural carbohydrates (lignin and cellulose) in leaves significantly (at 5 % level) influenced k values. The SOC and carbon isotope data collected in this study indicate that C₃ vegetation cover in the study area could be contemporary and dominant for the past few centuries. This can be extended up to ~2,200 years from the recorded ¹⁴C values of teak cover. The study confirms that k values of leaf litter influence SOC present beneath the vegetation cover at the decadal/century time scale.     

Purification and characterization of 9-O-acetylated sialoglycoproteins from leukemic cells and their potential as immunological tool for monitoring childhood acute lymphoblastic leukemia

Sialic acids as terminal residues of oligosaccharide chains play crucial roles in several cellular recognition events. Exploiting the selective affinity of Achatinin-H toward N-acetyl-9-O-acetylneuraminic acid-alpha2-6-GalNAc, we have demonstrated the presence of 9-O-acetylated sialoglycoproteins (Neu5,9Ac(2)-GPs) on lymphoblasts of 70 children with acute lymphoblastic leukemia (ALL) and on leukemic cell lines by fluorimetric HPLC and flow cytometric analysis. This study aims to assess the structural aspect of the glycotope of Neu5,9Ac(2)-GPs(ALL) and to evaluate whether these disease-specific molecules can be used to monitor the clinical outcome of ALL. The Neu5,9Ac(2)-GPs(ALL) were affinity-purified, and three distinct leukemia-specific molecular determinants (135, 120, and 90 kDa) were demonstrated by SDS-PAGE, western blotting, and isoelectric focusing. The carbohydrate epitope of Neu5,9Ac(2)-GPs(ALL) was confirmed by using synthetic sialic acid analogs. The enhanced presence of anti-Neu5,9Ac(2)-GP(ALL) antibody in ALL patients prompted us to develop an antigen-ELISA using purified Neu5,9Ac(2)-GPs(ALL) as coating antigens. Purified antigen was able to detect leukemia-specific antibodies at presentation of disease, which gradually decreased with treatment. Longitudinal monitoring of 18 patients revealed that in the early phase of the treatment patients with lower anti-Neu5,9Ac(2)-GPs showed a better prognosis. Minimal cross-reactivity was observed in other hematological disorders (n = 50) like chronic myeloid leukemia, acute myelogenous leukemia, chronic lymphocytic leukemia, and non-Hodgkin's lymphoma as well as normal healthy individuals (n = 21). This study demonstrated the potential of purified Neu5,9Ac(2)-GPs(ALL) as an alternate tool for detection of anti-Neu5,9Ac(2)-GP antibodies to be helpful for diagnosis and monitoring of childhood ALL patients.     

Plant cell walls are enfeebled when attempting to preserve native lignin configuration with poly-p-hydroxycinnamaldehydes: evolutionary implications

The lignin deficient double mutant of cinnamyl alcohol dehydrogenase (CAD, cad-4, cad-5 or cad-c, cad-d) in Arabidopsis thaliana [Sibout, R., Eudes, A., Mouille, G., Pollet, B., Lapierre, C., Jouanin, L., Séguin, A., 2005. Cinnamyl alcohol dehydrogenase-C and -D are the primary genes involved in lignin biosynthesis in the floral stem of Arabidopsis. Plant Cell 17, 2059-2076], was comprehensively examined for effects on disruption of native lignin macromolecular configuration; the two genes encode the catalytically most active CAD's for monolignol/lignin formation [Kim, S.-J., Kim, M.-R., Bedgar, D.L., Moinuddin, S.G.A., Cardenas, C.L., Davin, L.B., Kang, C., Lewis, N.G., 2004. Functional reclassification of the putative cinnamyl alcohol dehydrogenase multigene family in Arabidopsis. Proc. Natl. Acad. Sci., USA 101, 1455-1460]. The inflorescence stems of the double mutant presented a prostrate phenotype with dynamic modulus properties greatly reduced relative to that of the wild type (WT) line due to severe reductions in macromolecular lignin content. Interestingly, initially the overall pattern of phenolic deposition in the mutant was apparently very similar to WT, indicative of comparable assembly processes attempting to be duplicated. However, shortly into the stage involving (monomer cleavable) 8-O-4' linkage formation, deposition was aborted. At this final stage, the double mutant had retained a very limited ability to biosynthesize monolignols as evidenced by cleavage and release of ca. 4% of the monolignol-derived moieties relative to the lignin of the WT line. In addition, while small amounts of cleavable p-hydroxycinnamaldehyde-derived moieties were released, the overall frequency of (monomer cleavable) 8-O-4' inter-unit linkages closely approximated that of WT for the equivalent level of lignin deposition, in spite of the differences in monomer composition. Additionally, 8-5' linked inter-unit structures were clearly evident, albeit as fully aromatized phenylcoumaran-like substructures. The data are interpreted as a small amount of p-hydroxycinnamaldehydes being utilized in highly restricted attempts to preserve native lignin configuration, i.e. through very limited monomer degeneracy during template polymerization which would otherwise afford lignins proper in the cell wall from their precursor monolignols. The defects introduced (e.g. in the vascular integrity) provide important insight as to why p-hydroxycinnamaldehydes never evolved as lignin precursors in the 350,000 or so extant vascular plant species. It is yet unknown at present, however, as to what levels of lignin reduction can be attained in order to maintain the requisite properties for successful agronomic/forestry cultivation. Nor is it known to what extent, if any, such deleterious modulations potentially compromise plant defenses. Finally, prior to investigating lignin primary structure proper, it is essential to initially define the fundamental characteristics of the biopolymer(s) being formed, such as inter-unit frequency and lignin content, in order to design approaches to determine overall sequences of linkages.     

Phenylalanine biosynthesis in Arabidopsis thaliana. Identification and characterization of arogenate dehydratases

There is much uncertainty as to whether plants use arogenate, phenylpyruvate, or both as obligatory intermediates in Phe biosynthesis, an essential dietary amino acid for humans. This is because both prephenate and arogenate have been reported to undergo decarboxylative dehydration in plants via the action of either arogenate (ADT) or prephenate (PDT) dehydratases; however, neither enzyme(s) nor encoding gene(s) have been isolated and/or functionally characterized. An in silico data mining approach was thus undertaken to attempt to identify the dehydratase(s) involved in Phe formation in Arabidopsis, based on sequence similarity of PDT-like and ACT-like domains in bacteria. This data mining approach suggested that there are six PDT-like homologues in Arabidopsis, whose phylogenetic analyses separated them into three distinct subgroups. All six genes were cloned and subsequently established to be expressed in all tissues examined. Each was then expressed as a Nus fusion recombinant protein in Escherichia coli, with their substrate specificities measured in vitro. Three of the resulting recombinant proteins, encoded by ADT1 (At1g11790), ADT2 (At3g07630), and ADT6 (At1g08250), more efficiently utilized arogenate than prephenate, whereas the remaining three, ADT3 (At2g27820), ADT4 (At3g44720), and ADT5 (At5g22630) essentially only employed arogenate. ADT1, ADT2, and ADT6 had k(cat)/Km values of 1050, 7650, and 1560 M(-1) S(-1) for arogenate versus 38, 240, and 16 M(-1) S(-1) for prephenate, respectively. By contrast, the remaining three, ADT3, ADT4, and ADT5, had k(cat)/Km values of 1140, 490, and 620 M(-1) S(-1), with prephenate not serving as a substrate unless excess recombinant protein (>150 microg/assay) was used. All six genes, and their corresponding proteins, are thus provisionally classified as arogenate dehydratases and designated ADT1-ADT6.     

Dibutyl phthalate, the bioactive compound produced by Streptomyces albidoflavus 321.2

It was found that the bioactive compound, dibutyl phthalate, was produced by a new soil isolate Streptomyces albidoflavus 321.2. Once this active compound was recovered by ethyl acetate from the fermented broth, being possible to isolate 13.4 mg/l, it was purified by paper, silica gel column, thin layer and gas chromatography. Structure was determined by analysing UV, IR and GC-MS spectra. During analysis, such active compound showed strong activity against gram-positive and gram-negative bacteria, as well as unicellular and filamentous fungi. The antimicrobial activity of the compound was reversed by the amino acid proline. No acute toxicity was observed.     

Insilico Study of Earthworm CCF1 Peptides in Earthworm

International Journal of Peptide Research and Therapeutics - The earthworms are known to possess a robust immune system that can combat pollutants and pathogens to which they are constantly exposed...