Bulb and Root Rot in Lily (Lilium longiflorum) and Onion (Allium cepa) in Israel

In the past 10 years, there has been a substantial increase in reports, from growers and extension personnel, on bulb and root rots in lily (Lilium longiflorum) in Israel. Rot in these plants, when grown as cut flowers, caused serious economic damage expressed in reduction in yield and quality. In lily, the fungal pathogens involved in the rot were characterized as binucleate Rhizoctonia AG‐A, Rhizoctonia solani, Pythium oligandrum, Fusarium proliferatum (white and purple isolates) and F. oxysporum, using morphological and molecular criteria. These fungi were the prevalent pathogens in diseased plants collected from commercial greenhouses. Pathogenicity trials were conducted on lily bulbs and onion seedlings under controlled conditions in a greenhouse to complete Koch's postulates. Disease symptoms on lily were most severe in treatments inoculated with binucleate Rhizoctonia AG‐A, P. oligandrum and F. proliferatum. Plant height was lower in the above treatments compared with the control plants. The least aggressive fungus was R. solani. In artificial inoculations of onion, seedling survival was significantly affected by all fungi. The most pathogenic fungus was F. proliferatum w and the least were isolates of F. oxysporum (II and III). All fungi were successfully re‐isolated from the inoculated plants.     

Rapid fluorescent assay for screening drugs on Leishmania amastigotes

A rapid fluorescent viability assay employing alamarBlue was optimized for use with Leishmania axenic amastigotes, the stage of the parasite responsible for disease pathology. The activity of two protein kinase inhibitors, Staurosporine and H-89, as well as Amphotericin B, on promastigotes and amastigotes of Leishmania donovani and Leishmania tropica was compared. Both protein kinase inhibitors inhibited promastigote growth at lower concentrations than amastigotes, while the GI(50) for Amphotericin B on both stages was similar. This assay only requires a limited number of axenic amastigotes (50,000 cells/well) and can be used to rapidly screen large chemical or natural product libraries for activity against amastigotes.     

A new Heck reaction modification using ketone Mannich bases as enone precursors: parallel synthesis of anti-leishmanial chalcones

A new Heck-type reaction for the synthesis of chalcones has been established using Mannich bases as enone precursors. The novel reaction proceeds rapidly in air atmosphere under ligandless conditions and can be adapted for library synthesis in a parallel reactor station. Screening of the synthesized chalcones revealed N-{4-[(1E)-3-oxo-3-(3-pyridinyl)-1-propenyl]phenyl}benzamide (3f) to be a potent anti-leishmanial agent.     

Overexpression of a diacylglycerol acyltransferase gene in Phaeodactylum tricornutum directs carbon towards lipid biosynthesis

Under nutrient deplete conditions, diatoms accumulate between 15% to 25% of their dry weight as lipids, primarily as triacylglycerols (TAGs). As in most eukaryotes, these organisms produce TAGs via the acyl‐CoA dependent Kennedy pathway. The last step in this pathway is catalyzed by diacylglycerol acyltransferase (DGAT) that acylates diacylglycerol (DAG) to produce TAG. To test our hypothesis that DGAT plays a major role in controlling the flux of carbon towards lipids, we overexpressed a specific type II DGAT gene, DGAT2D, in the model diatom Phaeodactylum tricornutum. The transformants had 50‐ to 100‐fold higher DGAT2D mRNA levels and the abundance of the enzyme increased 30‐ to 50‐fold. More important, these cells had a 2‐fold higher total lipid content and incorporated carbon into lipids more efficiently than the wild type (WT) while growing only 15% slower at light saturation. Based on a flux analysis using ¹³C as a tracer, we found that the increase in lipids was achieved via increased fluxes through pyruvate and acetyl‐CoA. Our results reveal overexpression of DAGT2D increases the flux of photosynthetically fixed carbon towards lipids, and leads to a higher lipid content than exponentially grown WT cells.     

Neuroprotective molecular mechanisms of (−)-epigallocatechin-3-gallate: a reflective outcome of its antioxidant, iron chelating and neuritogenic properties

Tea, the major source of dietary flavonoids, particularly the epicatechins, signifies the second most frequently consumed beverage worldwide, which varies its status from a simple ancient cultural drink to a nutrient component, endowed possible beneficial neuro-pharmacological actions. Accumulating evidence suggests that oxidative stress, resulting in reactive oxygen species generation, plays a pivotal role in neurodegenerative diseases, supporting the implementation of radical scavengers and metal chelating agents, such as natural tea polyphenols, for therapy. Vast epidemiology data indicate a correlation between occurrence of neurodegenerative disorders, such as Parkinson’s and Alzheimer’s diseases, and green tea consumption. In particular, recent literature strengthens the perception that diverse molecular signaling pathways, participating in the neuroprotective activity of the major green tea polyphenol, (−)-epigallocatechin-3-gallate (EGCG), renders this natural compound as potential agent to reduce the risk of various neurodegenerative diseases. In the current review, we discuss the studies concerning the mechanisms of action implicated in EGCG-induced neuroprotection and discuss the vision to translate these findings into a lifestyle arena.