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Phosphatidylinositol 3-kinases (PI3Ks) are characterized by the presence of a C2 domain at the N-terminal end (class I, III); or at both the N-terminal and C-terminal ends (class II), sometimes including a Plextrin homology domain and/or a Ras domain. Plant PI3Ks are analogous to the class III mammalian PI3K. An N-terminal fragment (~170 aa) of the tomato PI3K regulatory domain including the C2 domain, was cloned and expressed in a bacterial system. This protein was purified to homogeneity and its physicochemical properties analyzed. The purified protein showed strong binding with monophosphorylated phosphatidylinositols, and the binding was dependent on calcium ion concentration and pH. In the overall tertiary structure of PI3K, C2 domain showed unique characteristics, having three antiparallel beta-sheets, hydrophobic regions, acidic as well as alkaline motifs, that can enable its membrane binding upon activation. To elucidate the functional significance of C2 domain, transgenic tobacco plants expressing the C2 domain of PI3K were generated. Transgenic plants showed defective pollen development and disrupted seed set. Flowers from the PI3K–C2 transgenic plants showed delayed wilting, and a decrease in ethylene production. It is likely that introduction of the PI3K–C2 segment may have interfered with the normal binding of PI3K to the membrane, delaying the onset of membrane lipid catabolism that lead to senescence. Image 1 • Tomato PI3K–C2 fragment was cloned, purified and biochemically characterized. • Transgenic tobacco plants expressing the C2-GFP domain were generated. • Flowers from the transgenic plants showed delayed flower senescence. • Over-expression of C2 may have interfered with the normal binding of PI3K to the membrane, delaying senescence. [ABSTRACT FROM AUTHOR]

Membrane deterioration is an inherent aspect of the advancement in senescence and loss in fruit quality during storage. Postharvest technologies used for extending shelf life and quality are targeted to reduce membrane damage through downregulating or blocking ethylene action. In this study, mature green tomato fruit were treated with inhibitors of ethylene receptor (ETR), phosphatidylinositol 3-kinase (PI3K) and phospholipase D (PLD), all recognized to be targets of regulation of fruit ripening. The inhibitors used included 1-methylcyclopropene (1-MCP, an ethylene receptor blocker), wortmannin (an inhibitor of PI3K), and hexanal (a PLD inhibitor). Fruit were treated at optimal levels of the inhibitors and were stored at 21 °C for 10 days. Color development was strongly delayed in wortmannin treated tomatoes just as in 1-MCP treated fruit; while, changes in respiration, firmness and ethylene evolution were very similar to that of control fruit. Hexanal delayed the initiation of these changes; while 1-MCP and wortmannin blocked the ripening process. Changes in expression levels of key genes involved in ethylene signalling, phosphoinositide metabolism, and lycopene synthesis that occurred in response to inhibitors, suggested potential roles for PI3K and PLD in ethylene signalling. Furthermore, fruit treated with all the three inhibitors showed a marked reduction in PLD transcript levels; suggesting that, regulation of PLD gene expression is a common critical regulatory point that regulates ripening. Lowered PLD levels may reduce membrane lipid catabolism and the generation of phosphatidic acid (PA), an intermediate in ethylene signalling regulation through downstream components. [ABSTRACT FROM AUTHOR]

Aqueous compositions of hexanal, an inhibitor of phospholipase D, has been shown to enhance the shelf life and quality of fruits and vegetables. In the present study, sweet bell pepper fruit were exposed to hexanal vapor and its effect on quality attributes, shelf-life, and antioxidant enzyme activities were evaluated during storage at 7 day intervals for 21 d. Peppers subjected to hexanal vapor treatments (0.005, 0.01, and 0.02%, w/w) showed a significant (p < 0.05) delay in ripening process and preservation of postharvest qualities than untreated peppers, even at 21 d of storage. Treated fruit were characterized by increased firmness, a reduction in physiological water loss and lower electrical conductivity than control fruit, which indicated better membrane preservation. These treatments also resulted in an increase in the levels of antioxidant enzyme activities, specifically that of superoxide dismutase, catalase, glutathione reductase and guaiacol peroxidase. Evidences from the present study indicate that postharvest hexanal vapor treatment at optimal levels can effectively enhance the quality and shelf life of sweet bell peppers. [ABSTRACT FROM AUTHOR]

Primulina dryas ( P. dryas ), a popular ornamental plant species has recently gained interest among hobbyists and collectors due to its attractive foliage and flowers. An efficient protocol for in vitro regeneration of P. dryas from leaf and petiole explants was developed using thidiazuron (TDZ) as the sole inductive stimulus. The objective of this study was to evaluate the potential of P. dryas for mass propagation in vitro. Orientation of the explants on the culture medium also affected regeneration with significant enhancement in the number of shoots and somatic embryos when the abaxial surface of the leaf was in contact with the culture medium. Explants also showed a capacity to regenerate on a medium devoid of growth regulators indicating active endogenous hormone metabolism sufficient to stimulate de novo differentiation. The inhibitors of auxin biosynthesis and transport, p -chlorophenoxyisobutyric acid (PCIB) and 2,3,5-triiodobenzoic acid (TIBA) significantly reduced regeneration in an optimal growth environment suggesting the involvement of endogenous auxin in regeneration of P. dryas . Growth and development of regenerants was further improved in temporary immersion bioreactors and the resulting plants were successfully transplanted in the greenhouse. High efficiency and reproducibility of Primulina regeneration system reported here may facilitate large scale production of this ornamental species. [ABSTRACT FROM AUTHOR]

Highlights: [•] Quality of greenhouse tomato can be enhanced by preharvest application of hexanal-containing aqueous formulations and enhanced freshness formulation. [•] Postharvest dips in “enhanced freshness formulation” are also effective in enhancing shelf life of tomatoes. [•] Increased firmness, red colour, ascorbic acid levels, etc., are features observed in tomatoes treated with “enhanced freshness formulation” indicative of better quality. [Copyright &y& Elsevier]

Abstract: Sunflower (Helianthus annuus L.) is a commercially important oilseed crop. Previous studies proved that this crop is a promising plant species for phytoextraction of excess soil phosphorus (P) because of its superior P accumulating characteristics. Suppression subtractive hybridization (SSH) strategy was employed to isolate and characterize genes that are induced in response to high P in this crop. SSH library was prepared using cDNA generated from plants treated with high P as the ‘tester’. Based on the results of dot blot analysis, 360 positive cDNA clones were selected from the SSH library for sequencing. A total of 89 non-redundant expressed sequence tags (ESTs) were identified as high P-responsive genes and they were classified into 6 functional groups. Several genes involved in metabolism showed markedly preferential expression in the library. For further confirmation, thirteen of the representative ESTs were selected from all categories for RT-PCR analysis and the results showed up-regulation of these genes in response to high P-treatment. The gene expression data derived from this study suggested that several of the up-regulated genes identified under high P-treatment might be involved in P-accumulation and tolerance in this plant. [Copyright &y& Elsevier]

Abstract: Recurrent application of animal manure to the soil often results in accumulation of phosphorus (P) in the soil over time. Use of temperate forages like Lolium multiflorum capable of extracting excess P from manure impacted soil is an attractive strategy for P phytoremediation. Two genotypes of L. multiflorum, ‘Gulf and Marshall’ were grown in soil and hydroponic media containing various concentrations of poultry manure and their P accumulation potential was determined. A decline in the biomass with an increase in manure concentration beyond 10gkg−1 soil in Gulf and 25gkg−1 soil in Marshall was noticed. Gulf grass accumulated more P content (7gkg−1 dry weight) as compared to Marshall (6gkg−1 dry weight) in both roots and shoots. Maximum shoot P content was observed in the soil amended with 10g poultry manure, while root P was highest at the concentration of 50g poultry manurekg−1 in the soil. Both cultivars yielded the highest biomass when grown in the presence of 10g poultry manure in modified Hoagland''s media. Presence of chelators in the media did not produce any noticeable effect on P accumulation in either grass and the biomass was appreciably enhanced by all concentrations of the chelators. Gulf and Marshall ryegrass seedlings were grown hydroponically in various poultry manure fractions. Both phytase and acid phosphatase (APase) enzyme activities in the root increased substantially in response to P-sufficient condition. In the presence of various poultry manure fractions, an intermediate level of both enzymes was measured compared to the P-sufficient condition, while the lowest enzyme activity was observed in the absence of any P source in the media. The level of APase and phytase activities was more or less the same in the two grasses under various growth conditions. An additional APase isoform was induced specifically in response to P-starvation from the two grass cultivars. Phytase and APase assays carried out in the P-starved and P-replenished grass seedlings further confirmed that during P deficiency, the enzyme activity was lowest and results of PAGE indicated that an APase isoform was induced under P-starvation. [Copyright &y& Elsevier]

• Hexanal exposure for a minimum of 6 h was essential to delay pepper fruit ripening. • Head space hexanal concentration decreased in the presence of pepper fruit. • Volatile emission was higher in hexanal treated fruit. • Hexanal repressed carotenoid biosynthesis gene expression in pepper. • Phospholipase Dα expression was lnhibited in hexanal treated fruit. Phospholipase D (PLD) is a key enzyme involved in membrane lipid catabolism. Hexanal, a C6 volatile aldehyde is a strong PLD -inhibitor, and has been observed to enhance the shelf life and quality of horticultural produce. In the present study, the effect of hexanal vapor exposure on the postharvest quality and ripening response of bell pepper fruit was evaluated. Hexanal exposure for a minimum of 6 h was found to be essential to delay ripening in bell pepper fruit. Quantification of head space hexanal levels in the presence of pepper fruit revealed a gradual decrease in concentration, while it remained relatively steady close to the peak value in the absence of pepper fruit. Hexanal treated bell peppers subjected to 21 d of postharvest storage evolved higher levels of aroma volatiles than untreated peppers. Hexanal vapor treatment induced significant alterations in the transcript accumulation and expression of genes involved in the carotenoid biosynthetic pathway, antioxidant enzyme systems, and the LOX pathway in stored pepper fruit. Real time PCR analysis also confirmed the near-complete downregulation of expression of genes encoding PLD α, β, δ and ζ isoforms in hexanal vapor treated peppers. The results suggest that hexanal vapor treatment can beneficially influence the expression of genes in multiple biochemical pathways, which could ultimately result in enhancing the shelf life and quality of horticultural produce. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the impact of injectable agents on subsequent incontinence surgery outcomes to assess safety and efficacy of this treatment combination. Periurethral bulking agents are a minimally invasive treatment option for stress urinary incontinence (SUI), but often lack durability necessitating further surgical intervention. Methods: Retrospective review of 43 patients with SUI following bulking agent who underwent subsequent sling placement from November 2000 to September 2009 were evaluated for demographics, symptoms, urodynamics (UDS), bulking agent characteristics, concomitant procedures, pad requirements per day (PPD), subjective outcomes, and complications. Results: Mean patient age was 67 years, with mean follow-up of 37.3 months. All demonstrated SUI, and mixed urinary incontinence (MUI) was noted in 81.4%. Almost half (48.8%) had undergone a prior antiincontinence procedure. Mean number of injections was 3. After a bulking injection, 25 autologous fascia pubovaginal slings, 13 midurethral slings, and 5 biological pubovaginal slings were placed. Concomitant pelvic surgery was performed in 37.2%. Postoperatively, mean PPD decreased from 5.3 to 0.65, with a 60.5% subjective cure rate (no pads or leakage under any circumstances). No association was seen between number or type of injection, or type of sling with regards to patient outcomes. Results were significantly related to concomitant surgery (P = .007). SUI recurred in 8 patients (18.6%), which was not statistically associated with other parameters. Complications included urinary retention (8 patients) de novo urgency (1 patient), UTI (4 patients), abdominal wound infection (3 patients), and cystotomy (1 patient). Conclusions: Prior treatment with bulking agents does not appear to negatively affect outcomes for future antiincontinence surgery in our patient population. [ABSTRACT FROM AUTHOR]