A comparative proteome assay on the quality of yardlong bean pods as influenced by the organic and inorganic nourishment systems

The assumption of enhanced nutritional quality of food produced through the organic systems against the inorganic systems is under constant challenge. Changes in nutritional quality under varying methods of crop nourishment, if any, should be through the differential translation of proteins and hence should be reflected in the proteome profile. The present study was undertaken to understand the effect of organic and inorganic crop nourishments on the nutritional quality of yardlong bean, through two-dimensional proteome profiling. Yardlong beans were raised separately under organic and inorganic nourishment and the proteome of pods was profiled. The differentially expressed and upregulated proteins from immature and mature pods from both the systems were characterized through MALDI-ToF/MS. Under both the production systems, differentially expressed proteins were the contributors to antioxidant properties at different pod maturity stages and pod quality was proven to be independent of crop nourishment system. This study does not support the hypothesis that organically produced foods will be nutritionally superior.     

The very-high-density lipoprotein fraction of rabbit plasma is rich in tissue-derived cholesterol

When plasma from rabbits, which several weeks earlier had been infused with [3H]cholesterol, was subjected to equilibrium density gradient ultracentrifugation, the specific radioactivity of cholesterol in the very-high-density lipoprotein (VHDL) fraction (d 1.22-1.32 g/ml) was three to 8-fold greater (mean, 5.5-fold; P less than 0.001) than that in high-density lipoproteins (HDL; d 1.06-1.21 g/ml). On size exclusion chromatography of plasma, no increase in specific radioactivity was seen in particles smaller than HDL. These findings suggest that those apolipoprotein-lipid complexes that dissociate from HDL during ultracentrifugation to form the VHDL fraction contain proportionately more tissue-derived cholesterol than do those that are more tightly bound to HDL.     

Retinal Muller glia initiate innate response to infectious stimuli via toll-like receptor signaling

Ocular surgeries and trauma predispose the eye to develop infectious endophthalmitis, which often leads to vision loss. The mechanisms of initiation of innate defense in this disease are not well understood but are presumed to involve retinal glial cells. We hypothesize that retinal Muller glia can recognize and respond to invading pathogens via TLRs, which are key regulators of the innate immune system. Using the mouse retinal sections, human retinal Muller cell line (MIO-M1), and primary mouse retinal Muller cells, we show that they express known human TLR1-10, adaptor molecules MyD88, TRIF, TRAM, and TRAF6, and co-receptors MD2 and CD14. Consistent with the gene expression, protein levels were also detected for the TLRs. Moreover, stimulation of the Muller glia with TLR 2, 3, 4, 5, 7 and 9 agonists resulted in an increased TLR expression as assayed by Western blot and flow cytometry. Furthermore, TLR agonists or live pathogen (S. aureus, P. aeruginosa, & C. albicans)-challenged Muller glia produced significantly higher levels of inflammatory mediators (TNF-α, IL-1β, IL-6 and IL-8), concomitantly with the activation of NF-κB, p38 and Erk signaling. This data suggests that Muller glia directly contributes to retinal innate defense by recognizing microbial patterns under infectious conditions; such as those in endophthalmitis.     

LDL and HDL transfer rates across peripheral microvascular endothelium agree with those predicted for passive ultrafiltration in humans

The mechanisms by which LDLs and HDLs cross the vascular endothelium from plasma into interstitial fluid are not understood, and have never been studied in humans in vivo. We determined whether the plasma-to-lymph clearance rates of LDL and HDL conform with those predicted by passive ultrafiltration through intercellular pores, or if it is necessary to invoke an active process such as receptor-mediated transcytosis. Plasma and afferent peripheral lymph were collected under steady-state conditions from 30 healthy men, and assayed for seven globular proteins of molecular radii 2.89–8.95 nm, complement C3, and apo AI, apo AII, and apo B. Plasma-to-lymph clearance rates of the seven proteins fitted the relation expected for molecules of their size when transported through two populations of pores of radius 4.95 and 20.1 nm. The same model parameters were then found to accurately predict the clearance rates of both HDL and LDL. The apparent clearance of complement C3, previously shown to be secreted by cultured endothelium, exceeded that predicted by the model. We conclude that the transport of HDL and LDL from plasma into interstitial fluid across the peripheral vascular endothelium in healthy humans can be explained by ultrafiltration without invoking an additional active process such as transcytosis.     

Hormonal determinants of apolipoprotein B,E receptor expression in human liver. Positive association of receptor expression with plasma estrone concentration in middle-aged/elderly women

The relationships of the expression of hepatic low-density lipoprotein (LDL) receptors (apo B,E receptors) to several plasma hormone concentrations were examined in 15 fasted women aged 37-75 years (mean, 57 years), who were undergoing laparotomy for non-neoplastic disease. No subject had clinical or biochemical evidence of familial hypercholesterolemia, renal disease, hepatic disease, or endocrine disease. Hepatic apo B,E receptor expression was quantified in vitro as the EDTA-suppressible binding of 125I-labeled human LDL (15 micrograms protein/ml) by liver homogenate at 37 degrees C; values were 23-75 ng LDL protein/mg cell protein (mean, 47 ng/mg). Receptor expression was strongly correlated with plasma estrone concentration (rs = +0.70, P = 0.035), but was unrelated to the concentrations of testosterone, thyroxine, free triiodothyronine, cortisol, sex hormone-binding globulin (SHBG) or cortisol-binding globulin. Insulin and estradiol concentrations were mostly very low. The correlation of receptor expression with plasma total estrone concentration reflected associations with both the albumin-bound (rs = +0.78, P = 0.014) and unbound (rs = +0.80, P = 0.009) fractions, but not with the SHBG-bound fraction (rs = -0.22, P = 0.574), of this hormone. As the non-SHBG-bound fractions of gonadal steroids are considered to be the biologically active components, these results are consistent with experimental evidence that the synthesis of apo B,E receptors in hepatocytes is stimulated by estrogens, and suggest that circulating estrone may be the major hormonal determinant of receptor expression in fasted middle-aged/elderly women.     

Intravenous apoA-I/lecithin discs increase pre-beta-HDL concentration in tissue fluid and stimulate reverse cholesterol transport in humans

The extent to which plasma HDL concentration regulates reverse cholesterol transport (RCT) is not known. The principal acceptors of unesterified cholesterol (UC) from cultured cells are small pre-beta-HDL, which we have shown increase in plasma during intravenous infusion of apolipoprotein A-I/phosphatidylcholine (apoA-I/PC) discs in humans. We have now examined the effects on tissue fluid HDL and RCT. ApoA-I/PC or proapoA-I/PC discs were infused into 16 healthy males. Eleven had been given intravenous radiocholesterol to label tissue pools; in 12 prenodal leg lymph was collected throughout; and in 8 all feces were collected. The rise in small pre-beta-HDL in plasma was associated with increases in 1) pre-beta-HDL concentration in lymph (all subjects), 2) the size of other lymph HDL (four of four subjects), 3) the cholesterol content of lymph lipoproteins relative to plasma lipoproteins (P < 0.01, n = 4), 4) cholesterol-specific radioactivity in lymph (five of nine subjects), 5) plasma lathosterol (P < 0.004, n = 4), 6) plasma cholesterol esterification rate (P < 0.001, n = 4), and 7) fecal bile acid excretion (P < 0.001, n = 8). These results support the hypothesis that small pre-beta-HDL generated in plasma readily cross endothelium into tissue fluid, and thereby promote efflux of UC from peripheral cells. After delivery to the liver, peripheral cholesterol appears to be utilized more for bile acid synthesis than for biliary cholesterol secretion in humans.     

Distribution of phospholipid transfer protein in human plasma: presence of two forms of phospholipid transfer protein, one catalytically active and the other inactive

Plasma phospholipid transfer protein (PLTP) plays an important role in the maintenance of plasma high-density lipoprotein (HDL) content and remodeling of HDL in the circulation. In the present study we have used different fractionation methods to investigate the distribution of PLTP in human plasma. A novel enzyme-linked immunosorbent assay developed during the study allowed for simultaneous assessment of both PLTP mass and activity in the fractions obtained. Size-exclusion chromatography and plasma fractionation by nondenaturing polyacrylamide gel electrophoresis (PAGE) yielded similar results demonstrating that PLTP associates in native plasma with two distinct particle populations, while ultracentrifugation with high salt leads to detachment of PLTP from lipoprotein particles and loss of a majority of its phospholipid transfer activity. Interestingly, analysis of the size-exclusion chromatography fractions demonstrated that PLTP exists in the circulation as an active population that elutes in the position of HDL corresponding to an average molecular mass of 160+/-40 kDa and an inactive form with an average mass of 520+/-120 kDa. The inactive fraction containing approximately 70% of the total PLTP protein eluted between HDL and low density lipoprotein (LDL). Thus, the two PLTP pools are associated with different types of lipoprotein particles, suggesting that the PLTP activity in circulation is modulated by the plasma lipoprotein profile and lipid composition.