Endogenous stimulant of prostaglandin endoperoxide synthase activity in human amniotic fluid

In this study we describe the discovery and characterization of a substance in human amniotic fluid that stimulates prostaglandin biosynthesis by a microsome-enriched preparation of bovine seminal vesicles. The stimulatory activity is not retained substantially upon anisotropic ultrafiltration through a filter with a molecular weight exclusion limit of 500. Stimulation of prostaglandin biosynthesis by this substance is time- and concentration-dependent; maximal stimulation of approx. 200% being observed within 20 min of commencing incubation with 1 ml-equivalent of stimulant fraction. Stimulatory activity is demonstrable both in the presence of reduced glutathione (1.3 mM) and L-tryptophan (20 mM), either separately or combined, and in the presence of exogenous arachidonic acid (5-120 microM). In the absence of added cofactors, the stimulatory substance increases the rates of biosynthesis of prostaglandin E2 and prostaglandin F2 alpha to equal extents. The amount of stimulatory substance added to incubations is correlated positively with increased oxygen consumption during incubations. The stimulatory substance is stable to heating at 100 degrees C for 10 min but is inactivated substantially (to less than 20% of original activity) by treatment with pronase. It is concluded that human amniotic fluid contains a substance of relatively low molecular weight, which is proteinaceous in character, that stimulates prostaglandin endoperoxide synthase activity.     

Preparative purification of Escherichia coli heat-stable enterotoxin

Heat-stable enterotoxin (STa) isolated from bovine Escherichia coli strains was purified to homogeneity by growing the bacterial strains in a chemically defined medium, desalting, and concentrating the culture filtrate by batch adsorption chromatography on Amberlite XAD-2 resin, batch adsorption chromatography on reversed-phase silica, and preparative reversed-phase high-performance liquid chromatography. This rapid preparative purification scheme gave high recovery yields of pure STa which exhibited biochemical homology to STa purified by more complicated procedures.     

Synthesis of 2-acetamido-2-deoxy-4-O-β-d-galactopyranosyl-3-O-methyl-d-glucopyranose (N-acetyl-3-O-methyllactosamine) and its benzyl α-glycoside

Benzyl 2-acetamido-2-deoxy-3-O-methyl-α-d-glucopyranoside (3) was obtained by deacetalation of its 4,6-O-benzylidene derivative (2). Compound 2 was prepared by methylation of benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-α-d-glucopyranoside with methyl iodide-silver oxide in N,N-dimethylformamide. Diol 3 was selectively benzoylated and p-toluenesulfonylated, to give the 6-benzoic and 6-p-toluenesulfonic esters (4 and 5, respectively). Displacement of the sulfonyl group of 5 with sodium benzoxide in benzyl alcohol afforded the 6-O-benzyl derivative (6). Glycosylation of 4 with 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide (7) in dichloromethane, in the presence of 1,1,3,3-tetramethylurea, furnished the disaccharide derivative 8. Similar glycosylation of compound 6 with bromide 7 gave the disaccharide derivative 10. O-Deacetylation of 8 and 10 afforded disaccharides 9 and 11. The structure of compound 9 was established by ¹³C-n.m.r. spectroscopy. Hydrogenolysis of the benzyl groups of 11 furnished the disaccharide 2-acetamido-2-deoxy-4-O-β-d-galactopyranosyl-3-O-methyl-d-glucopyranose (N-acetyl-3-O-methyllactosamine).     

In vivo development and pathogenicity of Ascosphaera proliperda (Ascosphaeraceae) to the alfalfa leafcutting bee, Megachile rotundata

First instar larvae of the leafcutting bee, Megachile rotundata, were fed on either artificial or natural provisions containing spores of Ascosphaera proliperda. Two isolates were used as a source of inocula: one originated from in vitro isolates obtained while culturing what was thought to be pure spores of A. aggregata, the second originated from in vitro cultures from Denmark. Histological and scanning electron microscopy studies revealed that the spores germinated in the gut lumen and the developing hyphae invaded all tissues, after which they penetrated through larval integument and began the sexual phase of the life cycle aerially. Virtually all fungus-exposed larvae developed symptoms of disease regardless of source of inoculum, type of provision, and spore dose (1.5 × 10³ to 3 × 10⁶) per insect. It was concluded that the fungus was pathogenic to the alfalfa leafcutting bee under laboratory conditions and future studies should be conducted to determine its etiology, cross infectivity, and natural distribution in other bee taxa.     

Studies on the rhizosphere mycoflora of broad bean and cotton. Effect of fungal filtrate on plant growth

The dominating rhizosphere fungi of broad bean (Vicia faba Linn.) variety “Giza 1”, and cotton (Gossypium barbadense Linn.) variety “Giza 47”, were grown in liquid medium. After 10 days, filtrates were obtained and sterilized by filtration through sintered-glass filter. Plants were grown in sterile sand which was supplemented with nutrient solution. Every plant was irrigated with fungal filtrate, unconsumed medium, and water. The filtrates of the rhizosphere fungi of both broad bean and cotton stimulated plant growth.     

Design and operation of a simple continuous-culture apparatus

A versatile and simple continuous-culture apparatus is described. With this apparatus, independent control of limiting growth factors and other nutrilites is possible and the conditions of each experiment are reproducible. In view of the synchronized speed of the feeder syringes, flow variation troubles are not encountered. The device allows the performance of growth experiments at different dilution rates simultaneously in a single run which makes the comparison of the results more reliable. The operation of the device has been tested successfully with a study of adenine deaminase induction in yeast.     

Petiolar felt-sheath of palm: A new matrix for fungal immobilization

Summary Petiolar felt-sheath of palm (Livistona chinensis) has been successfully used as a new biostructural matrix for the immobilization of fungal hyphae. The reticulated felt-sheath is made up of fibrous bundles having irregularly scattered membranous-foliose and fibrous outgrowths woven into a cohesive multi-layered mesh. Immobilization of Aspergillus niger was achieved with both spore and hyphal suspensions as the inoculum. Growth in immobilized cultures was 19% greater than in free cultures.     

The Potential Efficacy of Glycyrrhizic Acid and Its Nanostructure Against Brown Rot of Peach fruits

Production of peaches (Prunus persica (L.) Batsch) for both local market and export is increasing each year in Egypt. Brown rot disease, caused by Monilinia laxa and Monilinia fructigena, is considered one of the most important postharvest rots affecting peaches in Egypt and economic losses are increasing. Antifungal activity of glycyrrhizic acid nanoparticles (GA-NPs) and glycyrrhizic acid (GA) at 0.2 and 0.4 mmol/L was investigated as a control for both these brown rot pathogens on peach fruits in both in vitro and in vivo studies. In the in vitro studies, GA-NPs were the most effective as shown by the ability to decrease linear growth of both brown rot pathogens in potato dextrose agar (PDA) amended with 0.4 mmol/L GA-NPs. Micrographs of M. fructigena exposed to 0.4 mmol/LGA showed mycelial deformations, nodule formation, detachment of the cell wall, shrinkage and inhomogeneous cytoplasmic materials with large vacuoles. Mycelium of M. laxa exposed to 0.4 mmol/ LGA-NPs resulted in thinner and distorted hyphae, nodule formation, cell wall thinning, and swellings. The GANPs and GA treatments improved fruit quality by maintaining firmness and total soluble solids (TSS). GA-NPs were more effective in decreasing decay incidence than their bulk material. The 0.4 mmol/L GA-NPs completely inhibited the disease on naturally infected peach fruits for both seasons of 2018 and 2019. Furthermore, 0.4 mmol/L GA-NPs reduced the disease incidence in inoculated fruits by 95 (M. laxa) and 88% (M. fructigena) in 2018 season and 96 (M. laxa) and 85% (M. fructigena) in 2019 season. In conclusion, GA-NPs could enhance the resistance of peaches against brown rot caused by M. laxa and M. fructigena.     

Molecular phylogenetic study of flavonoids in medicinal plants: a case study family Apiaceae

Journal of Plant Research - The current study examined the phylogenetic pattern of medicinal species of the family Apiaceae based on flavonoid groups production, as well as the overall mechanism of...