Dibenzylideneacetone analogues as novel Plasmodium falciparum inhibitors

A series of dibenzylideneacetones (A1-A12) and some of their pyrazolines (B1-B4) were synthesized and evaluated in vitro for blood stage antiplasmodial properties in Plasmodium falciparum culture using SYBR-green-I fluorescence assay. The compound (1E, 4E)-1,5-bis(3,4-dimethoxyphenyl)penta-1,4-dien-3-one (A9) was found to be the most active with IC₅₀ of 1.97 μM against chloroquine-sensitive strain (3D7) and 1.69 μM against chloroquine-resistant field isolate (RKL9). The MTT based cytotoxicity assay on HeLa cell line has confirmed that A9 is selective in its action against malaria parasite (with a therapeutic index of 166). Our results revealed that these compounds exhibited promising antiplasmodial activities which can be further explored as potential leads for the development of cheaper, safe, effective and potent drugs against chloroquine-resistant malarial parasites.     

Waste biomass of Nostoc linckia as adsorbent of crystal violet dye: Optimization based on statistical model

The potential of spent biomass of a hydrogen producing cyanobacterial strain Nostoc linckia from a hydrogen fermentor was studied for decolorization of a tri-phenylmethane dye, crystal violet. The waste cyanobacterial biomass immobilized in calcium alginate was used as a biosorbent and the process variables were optimized for maximum dye removal using the statistical response surface methodology (RSM). Batch mode experiments were performed to determine the kinetic behavior of the dye in aqueous solution allowing the computation of kinetic parameters. Influence of interacting parameters like temperature (25-35 °C), pH (4-8), initial dye concentration (100-200 mg/L) and cyanobacterial dose (0.2-0.4 g) on dye removal were examined using central composite design (CCD) which included two additional levels for each parameter. Second-order polynomial regression model, was applied which was statistically validated using analysis of variance. Ability of the immobilized biomass to decolorize the dye was maximum (72%) at pH 8.0, temperature 35 °C, 200 mg/L initial dye concentration and 0.2 g cyanobacterial dose. Adsorption of the dye on cell surface was further confirmed by scanning electron micrographs of the biomass before and after dye loading. FT-IR studies revealed that decolorization was due to biosorption mediated mainly by functional groups like hydroxyl, amide, carboxylate, methyl and methylene groups present on the cell surface.     

NONOates--polyethylenimine hydrogel for controlled nitric oxide release and cell proliferation modulation

In recent years, numerous research activities have been devoted to the controlled release of nitric oxide (NO) due to its potential as a restenosis inhibitor which inhibits the proliferation of vascular smooth muscle cells, the apoptosis of vascular endothelial cells, and aggregation of platelets. This work has demonstrated the development of a novel NO-conjugated gel system comprising of thermosensitive Pluronic F127, branched polyethylenimine (BPEI), and diazeniumdiolates (NONOates). Synthesis of conjugated Pluronic-BPEI-NONOates involved coupling of activated F127 to BPEI followed by the installation of NONOates at the secondary amine sites of branched PEI backbone under high pressure. NO-conjugated gel system, F127-BPEI-NONOates, reduced the initial burst of NO release and prolonged NO release. Furthermore, F127-BPEI-NONOates polymer coated on cell culture dish displayed much higher increase of endothelial cell proliferation and reduction of smooth muscle cell proliferation than that exhibited by non-NO releasing control. Such an NO-releasing device can operate locally and has a great potential in several biomedical applications due to high biocompatibility imparted by the conjugated F127.     

Microautophagy of cytosolic proteins by late endosomes

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Highlights? Late endosomes take up cytosolic proteins through membrane invaginations ? Endosomal microautophagy (eMI) requires multivesicular body formation ? hsc70 mediates selective targeting of cytosolic proteins during eMI ? hsc70 binds to the endosomal membrane through its polybasic cluster     

Nutritional and hormonal control of lipolysis in isolated gilthead seabream (Sparus aurata) adipocytes

We examined the effects of diet composition and fasting on lipolysis of freshly isolated adipocytes from gilthead seabream (Sparus aurata). We also analyzed the effects of insulin, glucagon, and growth hormone (GH) in adipocytes isolated from fish fed with different diets. Basal lipolysis, measured as glycerol release, increased proportionally with cell concentration and time of incubation, which validates the suitability of these cell preparations for the study of hormonal regulation of this metabolic process. Gilthead seabream were fed two different diets, FM (100% of fish meal) and PP (100% of plant protein supplied by plant sources) for 6 wk. After this period, each diet group was divided into two groups: fed and fasted (for 11 days). Lipolysis was significantly higher in adipocytes from PP-fed fish than in adipocytes from FM-fed fish. Fasting provoked a significant increase in the lipolytic rate, about threefold in isolated adipocytes regardless of nutritional history. Hormone effects were similar in the different groups: glucagon increased the lipolytic rate, whereas insulin had almost no effect. GH was clearly lipolytic, although the relative increase in glycerol over control was lower in isolated adipocytes from fasted fish compared with fed fish. Together, we demonstrate for the first time that lipolysis, measured in isolated seabream adipocytes, is affected by the nutritional state of the fish. Furthermore, our data suggest that glucagon and especially GH play a major role in the control of adipocyte lipolysis.     

Effects of low protein intake on extra-hepatic gluconeogenic enzyme expression and peripheral glucose phosphorylation in rainbow trout (Oncorhynchus mykiss)

The objective of the study described here was to analyze in rainbow trout (Oncorhynchus mykiss) the effects of low protein intake on peripheral glucose phosphorylation capacities and gluconeogenic enzymes in kidney and intestine. Fish were food-deprived for 14 days or kept under a low and a high protein intake regime using a pair feeding protocol in order to maintain constant carbohydrate and lipid intakes. We analyzed the effect of protein restriction on (i) hepatic, renal and intestinal fructose-1.6-bisphophatase (FBPase) and glucose-6-phosphatase (G6Pase) enzymes at the molecular and enzymatic levels and (ii) glucose phosphorylation activities (hexokinases) in the liver, peri-visceral adipose tissue, red muscle and white muscle. Irrespective of the nutritional status, we observed the same levels of hexokinase activities in all the tissues studied. Renal G6Pase and FBPase gene expression and activities were not modified among the groups. In contrast, there was increased intestinal FBPase gene expression in fish under a low protein intake and higher G6Pase activities in both groups of fed fish. This result differs from what is observed in rats and suggest a role of intestine in the regulation of postprandial gluconeogenesis in fed trout. In conclusion, our data did not demonstrate any specific effect of low dietary protein intake to either gluconeogenic capacities or glucose phosphorylation capacities in rainbow trout.     

Molecular characterization of gilthead sea bream (Sparus aurata) lipoprotein lipase. Transcriptional regulation by season and nutritional condition in skeletal muscle and fat storage tissues

Lipoprotein lipase (LPL) of gilthead sea bream (Sparus aurata) was cloned and sequenced using a RT-PCR approach completed by 3' and 5'RACE assays. The nucleotide sequence covered 1669 bp with an open reading frame of 525 amino acids, including a putative signal peptide of 23 amino acids long. Sequence alignment and phylogenetic analysis revealed a high degree of conservation among most fish and higher vertebrates, retaining the consensus sequence the polypeptide "lid", the catalytic triad and eight cysteine residues at the N-terminal region. A tissue-specific regulation of LPL was also found on the basis of changes in season and nutritional condition as a result of different dietary protein sources. First, the expression of LPL in mesenteric adipose tissue was several times higher than in liver and skeletal muscle. Secondly, the spring up-regulation of LPL expression in the mesenteric adipose tissue was coincident with a pronounced increase of whole body fat content. Thirdly, the highest expression of LPL in the skeletal muscle was found in summer, which may serve to cover the increased energy demands for muscle growth and protein accretion. Further, in fish fed plant-protein-based diets, hepatic LPL expression was up-regulated whereas an opposite trend was found in the mesenteric adipose tissue, which may contribute to drive dietary lipids towards liver fat storage. Finally, it is of interest that changes in circulating triglyceride (TG) levels support the key role of LPL in the clearance of TG-rich lipoproteins. This study is the first report in fish of a co-regulated expression of LPL in oxidative and fat storage tissues under different physiological conditions.     

Sufficient progesterone-priming prior to estradiol stimulation is required for optimal induction of the cervical prostaglandin system in pregnant sheep at 0.7 gestations

The purposes of this study were to determine the separate and interactive functions of progesterone and estradiol in regulating the cervical prostaglandin (PG) system in pregnant sheep at 0.7 gestations. At 106-108 days of gestational age (dGA), ewes were treated with vehicle for 14 days (n = 5) or vehicle for 12 days followed by estradiol 5 mg twice a day, intramuscularly for 2 days (n = 5) or progesterone 100 mg, twice a day, intramuscularly for 14 days (n = 5) or progesterone 100 mg twice a day, intramuscularly for 10 days and then 2 days vehicle followed by estradiol 5 mg twice a day intramuscularly for 2 days (n = 5). At 121-123 dGA, cervical tissues were obtained under halothane anesthesia. Cervical RNA and protein were extracted and analyzed for prostaglandin-endoperoxide synthase 2 (COX2), two PGE(2) receptors, PTGER2 and PTGER4, and estrogen receptor alpha (ESR1) by Northern and Western blot analysis. Immunocytochemistry and in situ hybridization were applied to localize cellular distribution of COX2, PTGER2, and PTGER4 in the cervix. Data were analyzed by ANOVA. COX2 and PTGER4 mRNAs and proteins were increased (P < 0.05) in ewes treated with combined estradiol and progesterone but not in ewes treated with estradiol or progesterone alone compared with controls. ESR1 mRNA was increased in ewes treated with progesterone and estradiol plus progesterone. In contrast, PTGER2 mRNA and protein remained the same after all treatments. COX2 mRNA and protein were localized only in cervical glandular epithelial cells, whereas PTGER2 and PTGER4 were localized in both cervical glandular epithelial and smooth muscle cells. In conclusion, these data suggest that additional progesterone priming at 0.7 gestations synergizes with estradiol to induce cervical COX2, PTGER4, and ESR1 and support our hypothesis that stimulation of the cervical PG system by estradiol is optimized by sufficient progesterone priming in the pregnant sheep cervix.