MicroRNA signature in hepatocellular carcinoma patients: identification of potential markers

MicroRNAs (miRNAs) play important roles in liver pathologies and they are potential biomarkers for diagnosis of liver diseases progression. Changes in miRNA sera expression can be used as non-invasive biomarkers for hepatocellular carcinoma (HCC). The aim of the study was to identify the miRNome profiling of HCC and its diagnostic value in distinguishing HCC from healthy individuals. Expression profiles of miRNAs in serum samples of 20 HCC patients and 10 healthy controls were detected. Whole miRNome profiling was done using next generation sequencing. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic performance of the deregulated miRNAs for discriminating HCC cases from healthy controls. MiRNA 142 was highly expressed in HCC (P value?=?0.023) while miRNAs 191, 22, and 126 were higher in the controls (P value?=?0.005, 0.034, 0.010 respectively). We have identified 5 novel miRNAs and they were highly expressed in HCC than controls. Analysis of ROC curve demonstrated that these deregulated miRNAs can be used as a reliable biomarker for detection of HCC with high diagnostic accuracy (AUC?=?0.93). We have detected a panel of serum miRNAs that can be used as a reliable noninvasive screening biomarker of HCC. The study recommends further research to shed light on a possible role of the newly discovered novel miRNAs in HCC pathogenesis.

     

Implication of an Asp residue in the ribonucleolytic activity of hirsutellin A reveals new electrostatic interactions at the active site of ribotoxins

Ribotoxins are fungal extracellular ribonucleases that specifically cleave ribosomes leading to cell-death via apoptosis. α-Sarcin is the ribotoxin studied in deepest detail, and therefore constitutes the referential protein for the whole family. It has been demonstrated that ribotoxin activity depends on a very precise structural microenvironment in which electrostatic interactions among residues in the active site are of the highest importance. Hirsutellin A (HtA) has been recently described as the smallest ribotoxin known to date, encompassing all the abilities of previously characterized members of this family into a shorter sequence. Comparison of HtA and α-sarcin three-dimensional structures suggested that residues presumably forming the catalytic triad of HtA would be His 42, Glu 66, and His 113. Within this same idea, the presence of an Asp residue (Asp 40) in a position equivalent to α-sarcin Tyr 48 is highlighted as a novelty in this field. In this work, substitution mutants H42Q, E66Q and H113Q, as well as double and triple mutants in all possible combinations, are studied regarding their ribonucleolytic activity and cytotoxicity. Implication of these three residues in the ribotoxin activity of HtA is confirmed, though none of them is strictly essential for ribosomal cleavage. Studies with mutants D40N and D40N/E66Q demonstrate an important role for Asp 40 in the activity of HtA and establish a new set of electrostatic interactions different from the one described for already known ribotoxins.     

Isolation of Two Plasticizers,Bis(2-ethylhexyl) Terephthalate and Bis(2-ethylhexyl) Phthalate,from Capparis spinosa L. Leaves

Many plants have been known to be contaminated and accumulate plasticizers from the environment, including water sources, soil, and atmosphere. Plasticizers are used to confer elasticity and flexibility to various fiber and plastic products. Consumption of plasticizers can lead to many adverse effects on human health, including reproductive and developmental toxicity, endocrine disruption, and cancer. Herein, we report for the first time that two plasticizers, bis(2-ethylhexyl) terephthalate (DEHT) and bis(2-ethylhexyl) phthalate (DEHP), have been isolated from the leaves of Capparis spinosa L. (the caper bush), a plant that is widely used in food seasonings and traditional medicine. 297 mg/kg of DEHT and 48 mg/kg of DEHP were isolated from dried and grounded C. spinosa L. leaves using column chromatography and semi-preparative high-performance liquid chromatography. Our study adds to the increase in the detection of plasticizers in our food and medicinal plants and to the alarming concern about their potential adverse effects on human health.     

Synthesis and FTIR Conformational Studies of Peptides From the Basic Region of c-Jun: a Critical Analysis on the Basis of CD and NMR Data

Abstract

The peptide (35 residues) corresponding to the basic subdomain (bSD) of c-Jun (residues 252–281) and its fragments NP (N-terminal peptide, 1–19) and CP (C-terminal peptide, 1635) were synthesized in stepwise solid-phase using the tert-butyloxycarbonyl/benzyl strategy. In a previous paper, we have shown that during its binding to the DNA site CRE (cAMP- responsive element) the bSD structure was converted into α-helix from an initial random coil conformation [Krebs, D., Dahmani, B., El Antri, S., Monnot, M., Convert, O., Mauffret, O., Troalen, F. & Fermandjian, S. Eur. J. Biochem. 231, 370–380 (1995)]. Our results suggested both a high flexibility and a helical potential in bSD, these two properties seeming crucial for the accommodation of the basic subdomain of c-Jun to its specific DNA targets. In this work, we assessed the conformational variability of bSD through the study of the secondary structures of its NP and CP fragments in trifluoroethanol (TFE)/²H₂O mixtures, using Fourier transform infrared (FTIR) spectroscopy. The IR results were critically analyzed in light of our previously reported circular dichroism (CD) and NMR data [Krebs, D., Dahmani, B., Monnot, M., Mauffret, O., Troalen, F. & Fermandjian, S. Eur. J. Biochem. 235, 699–712 (1996)]. Upon addition of TFE, the relative areas of the seven components of the amide I band (1700–1620 cm^?1) reflected the conversion of a large amount of random coil conformation into α-helix for the two fragments and bSD. This effect was accompanied by more subtle variations of the less populated structures, in agreement with the results of CD and NMR experiments. The IR results stipulated the conservation of the parent bSD secondary structures in both fragments; however, NP and CP peptides did not display similar random-to-α-helix stabilization pattern upon additions of TFE to aqueous solutions. The profile from CD signal at 222 nm was found sigmoidal for NP and almost linear for CP, while that corresponding to the parent peptide bSD was just in between those of its fragments. Thus, the present study confirms the high flexibility and helix propensity of the c-Jun basic subdomain and suggests that the N- and C-terminal parts of the peptide do not follow the same random-to-helix conversion profile during their complexation with DNA.     

Foliar Application of Phosphorus Enhances Photosynthesis and Biochemical Characteristics of Maize under Drought Stress

Water is essential for the growth period of crops; however, water unavailability badly affects the growth and physiological attributes of crops, which considerably reduced the yield and yield components in crops. Therefore, a pot experiment was conducted to investigate the effect of foliar phosphorus (P) on morphological, gas exchange, biochemical traits, and phosphorus use efficiency (PUE) of maize (Zea mays L.) hybrids grown under normal as well as water deficit situations at the Department of Agronomy, University of Agriculture Faisalabad, Pakistan in 2014. Two different treatments (control and P @ 8 kg ha⁻¹ ) and four hybrids (Hycorn, 31P41, 65625, and 32B33) of maize were tested by using a randomized complete block design (RCBD) with three replications. Results showed that the water stress caused a remarkable decline in total soluble protein (9.7%), photosynthetic rate (9.4%) and transpiration rate (13.4%), stomatal conductance (10.2%), and internal CO₂ rate (20.4%) comparative to well-watered control. An increase of 37.1%, 36.8%, and 24.5% were recorded for proline, total soluble sugar, and total free amino acid, respectively. However, foliar P application minimized the negative impact of drought by improving plant growth, physio-biochemical attributes, and PUE in maize plants under water stress conditions. Among the hybrids tested, the hybrid 6525 performed better both under stress and non-stress conditions. These outcomes confirmed that the exogenous application of P improved drought stress tolerance by modulating growth, physio-biochemical attributes, and PUE of maize hybrids.     

Antitumor activity of antimicrobial peptides against U937 histiocytic cell line

We investigated cytotoxic activity of antimicrobial peptides of different origin (both naturally occurring and synthetic), structure and known mechanisms of action against human histiocytic lymphoma cell line U937. The strongest cytotoxic activity against U937 cell line was shown by Pexiganan MSI-78, followed by Citropin 1.1, Protegrin 1 and a synthetic lipopeptide, N-α-palmitoyl-L-lysyl-L-lysine amide (Pal-Lys-Lys-NH?). The cytotoxic activity of the peptides was more dependent on the time of incubation than concentration. Only for the lipopeptide, whose mode of action was restricted to disruption of electric potential of the cell membrane, the correlation between cytotoxicity and concentration was almost linear. The high cytotoxicity of Pexiganan MSI-78, Protegrin 1 and the lipopeptide could be basically explained by their membranolytic activity leading to necrosis. However, in the case of Citropin 1.1, the cell membrane integrity was disrupted only slightly and independently of the peptide concentration. Therefore, some other mechanism of action might be responsible for its strong dose-dependent cytotoxic activity, e.g., membranolytic activity leading to apoptosis. Furthermore, TNF-α production due to LPS (lipopolysaccharide) stimulation was suppressed by the presence of Citropin 1.1, Pexiganan MSI-78 or Protegrin 1, but not by Buforin 2 or the lipopeptide. Our experiments have shown that cytotoxic activity is not limited to some specific molecular structure of a peptide, but rather to the length of the peptide chain as it is likely to affect the efficiency of the tumor cell membrane disruption and interaction with LPS.     

High-performance reversed-phase chromatographic mapping of 2-pyridylamino derivatives of xyloglucan oligosaccharides.

Xyloglucan oligosaccharides from cotton cell walls and tamarind seeds were derivatized with 2-aminopyridine and subsequently separated by reversed-phase chromatography (r.p.c.) using an octadecylsilyl silica stationary phase and aqueous-organic eluents with 0.01% (v/v) trifluoroacetic acid. The chromatographic behavior of the 2-pyridylamino derivatives of xyloglucan oligosaccharides was examined under a wide range of elution conditions, including gradient steepness and shape, initial acetonitrile concentration in the eluent, and pore size of the r.p.c. packings. Relatively steep acetonitrile gradients resulted in poor resolution of the different xyloglucan fragments, which is believed to be the result of acetonitrile-induced conformational changes. Under these circumstances the elution order of the derivatized xyloglucan oligosaccharides was such that the smaller fragments eluted from the column before the larger ones. R.p.c. packing with a 70-A pore size necessitated relatively high acetonitrile concentration in the eluent when compared with 300-A stationary phase. The r.p.c. mapping of 2-pyridylamino derivatives of xyloglucan oligosaccharides was best achieved when both a wide-pore octadecyl-silyl silica stationary phase and a shallow gradient with consecutive linear segments of increasing acetonitrile concentration in the eluent were employed. This combination yielded rapid r.p.c. maps of the xyloglucan fragments from different sources with high separation efficiencies and concomitantly high resolution. The effects of the nature of the sugar residues in the xyloglucan oligomers and their degree of branching on r.p.c. retention and selectivity are also highlighted.