Allomones confer resistance to Musa cultivar Pisanglilin against infestation by Odoiporus longicollis [Oliver] and characterization of Allomones

In bioassay guided extraction of pseudostem powder of Pisanglilin by organic solvents we found the larvicidal activity in acetone extract, whose column chromatography by methanol-chloroform mixture separated the extract into 9-fractions, of which the 8th fraction showed larvicidal activity. Subfractionation of the active fraction by column chromatography resulted in the isolation of two larvicidal molecules [Stigmasterol-3-O-glucoside (SOG) and Sulfoquinovosyl diacylglycerol (SQDG)]. Yield of SOG was 0.002 % and SQDG was 0.005 % and both were highly toxic to O. longicollis larvae with LD50 of 0.40 and 0.378 ppm, respectively. Larvae fed these compounds stopped feeding on third day and died within one week. SOG inhibited the amylase and protease activity of gut and induced histolysis in the mid gut. While SQDG inhibited the leucine amino peptidase and trypsin like serine protease activities, which decreased the content of total free amino acids. Imbalance in the activities of aspartate amino transferase and alanine amino transferase disrupted the aminoacid metabolism and the compound inhibited the activity of tyrosinase (an enzyme involved in cuticle development). SQDG toxicity caused accumulation of 20-hydroxyecdysone, the active moulting hormone in the hemolymph. Simultaneous action of two allomones present in Pisanglilin effectively resisted the attack of endophytic larvae in the pseudostem and thereby conferred resistance against infestation by O.longicollis. Preliminary study by intrapseudostem injection of Pisanglilin extract in susceptible M.paradisiaca cultivar Kappa, gave complete protection to it from attack by this pest, under field condition.

Maricaulis alexandrii sp. nov., a novel dimorphic prosthecate and active bioflocculants-bearing bacterium isolated from phycosphere microbiota of laboratory cultured highly-toxic Alexandrium catenella LZT09

An aerobic, Gram-stain-negative, straight or curved rods, prosthecate bacterium designated as LZ-16-1T was isolated from phycosphere microbiota of highly-toxic and laboratory cultured dinoflagellate Alexandrium catenella LZT09. This new isolate produces active bioflocculanting exopolysaccharides (EPS). Cells were dimorphic with non-motile prostheca, or non-stalked and motile by a single polar flagellum. Growth occurred at 10-40 °C, pH 5–9 and 1–8 % (w/v) NaCl, with optimum growth at 25 °C, pH 7–8 and 2-4 % (w/v) NaCl, respectively. Phylogenetic analysis based on 16S rRNA indicated that strain LZ-16-1T was affiliated to the genus Maricaulis, and closely related to Maricaulis parjimensis MCS 25T (99.48%) and M. virginensis VC-5T (99.04%),. However, based on genome sequencing and phylogenomic calculations, the average nucleotide identity (ANI) and digtal DNA-DNA genome hybridization (dDDH) values between the two strains were only 85.0 and 20.9%, respectively. Strain LZ-16-1T owned Q-10 as predominant isoprenoid quinone; summed feature 8, C16:0, C17:0, C18:0, C18:1 ω9c and summed feature 9 as dominant fatty acids; and sulfoquinovosyl diacylglycerol, glycolipids and unidentified phospholipid as major polar lipids. The genomic DNA G+C content is 63.6 mol%. Physiological and chemotaxonomic characterization further confirmed the distinctiveness of strain LZ-16-1T from other Maricaulis members. Thus, strain LZ-16-1T represents a novel species of the genus Maricaulis, for which the name Maricaulis alexandrii sp. nov. (type strain LZ-16-1T=KCTC 72194T=CCTCC AB 2019006T) is proposed .

Glyceroglycolipid Metabolism Regulations under Phosphate Starvation Revealed by Transcriptome Analysis in Synechococcus elongatus PCC 7942

Glyceroglycolipids, abundant in cyanobacteria’s photosynthetic membranes, present bioactivities and pharmacological activities, and can be widely used in the pharmaceutical industry. Environmental factors could alter the contents and compositions of cyanobacteria glyceroglycolipids, but the regulation mechanism remains unclear. Therefore, the glyceroglycolipids contents and the transcriptome in Synechococcus elongatus PCC 7942 were analyzed under phosphate starvation. Under phosphate starvation, the decrease of monogalactosyl diacylglycerol (MGDG) and increases of digalactosyl diacylglycerol (DGDG) and sulfoquinovosyl diacylglycerol (SQDG) led to a decrease in the MGDG/DGDG ratio, from 4:1 to 5:3, after 12 days of cultivation. However, UDP–sulfoquinovose synthase gene sqdB, and the SQDG synthase gene sqdX, were down-regulated, and the decreased MGDG/DGDG ratio was later increased back to 2:1 after 15 days of cultivation, suggesting the regulation of glyceroglycolipids on day 12 was based on the MGDG/DGDG ratio maintaining glyceroglycolipid homeostasis. There are 12 differentially expressed transcriptional regulators that could be potential candidates related to glyceroglycolipid regulation, according to the transcriptome analysis. The transcriptome analysis also suggested post-transcriptional or post-translational regulations in glyceroglycolipid synthesis. This study provides further insights into glyceroglycolipid metabolism, as well as the scientific basis for glyceroglycolipid synthesis optimization and cyanobacteria glyceroglycolipids utilization via metabolic engineering.

Concise synthesis of sulfoquinovose and sulfoquinovosyl diacylglycerides, and development of a fluorogenic substrate for sulfoquinovosidases

A new and efficient synthesis of sulfoquinovose [including (13C6)-SQ] and of saturated and unsaturated sulfoquinovosyl diacylglycerol derivatives, and development of a fluorogenic glycoside useful for kinetic investigations on sulfoquinovosidases.

Synthesis of Sulfoquinovose and Sulfoquinovosyl Diacylglycerides, and a Fluorogenic Substrate for Sulfoquinovosidases

<p>The sulfolipid sulfoquinovosyl diacylglycerol (SQDG) and its headgroup, the sulfosugar sulfoquinovose (SQ), are estimated to harbour up to half of all organosulfur in the biosphere. SQ is liberated from SQDG and related glycosides by the action of sulfoquinovosidases (SQases). We report a 10-step synthesis of SQDG that we apply to the preparation of saturated and unsaturated lipoforms. We also report an expeditious synthesis of SQ and (¹³C₆)SQ, and X-ray crystal structures of sodium and potassium salts of SQ. Finally, we report the synthesis of a fluorogenic SQase substrate, methylumbelliferyl a-D-sulfoquinovoside, and examination of its cleavage kinetics by two recombinant SQases.</p>

Synthesis of Sulfoquinovose and Sulfoquinovosyl Diacylglycerides, and a Fluorogenic Substrate for Sulfoquinovosidases

<p>The sulfolipid sulfoquinovosyl diacylglycerol (SQDG) and its headgroup, the sulfosugar sulfoquinovose (SQ), are estimated to harbour up to half of all organosulfur in the biosphere. SQ is liberated from SQDG and related glycosides by the action of sulfoquinovosidases (SQases). We report a 10-step synthesis of SQDG that we apply to the preparation of saturated and unsaturated lipoforms. We also report an expeditious synthesis of SQ and (¹³C₆)SQ, and X-ray crystal structures of sodium and potassium salts of SQ. Finally, we report the synthesis of a fluorogenic SQase substrate, methylumbelliferyl a-D-sulfoquinovoside, and examination of its cleavage kinetics by two recombinant SQases.</p>

Re-modeling of foliar membrane lipids in a seagrass allows for growth in phosphorus deplete conditions

We used liquid chromatography high-resolution tandem mass spectrometry to analyze the lipidome of turtlegrass (Thalassia testudinum) leaves with extremely high phosphorus content and extremely low phosphorus content. Most species of phospholipids were significantly down-regulated in phosphorus-deplete leaves, whereas diacylglyceryltrimethylhomoserine (DGTS), triglycerides (TG), galactolipid digalactosyldiacylglycerol (DGDG), certain species of glucuronosyldiacylglycerols (GlcADG), and certain species of sulfoquinovosyl diacylglycerol (SQDG) were significantly upregulated, explaining the change in phosphorus content as well as structural differences in leaves of plants growing under diverse phosphate concentrations. These data suggest that seagrasses are able to modify the phosphorus content in leaf membranes dependent upon environmental phosphorus availability.