Downregulation of the Host Gene jigr1 by miR-92 Is Essential for Neuroblast Self-Renewal in Drosophila

Intragenic microRNAs (miRNAs), located mostly in the introns of protein-coding genes, are often co-expressed with their host mRNAs. However, their functional interaction in development is largely unknown. Here we show that in Drosophila, miR-92a and miR-92b are embedded in the intron and 3’UTR of jigr1, respectively, and co-expressed with some jigr1 isoforms. miR-92a and miR-92b are highly expressed in neuroblasts of larval brain where Jigr1 expression is low. Genetic deletion of both miR-92a and miR-92b demonstrates an essential cell-autonomous role for these miRNAs in maintaining neuroblast self-renewal through inhibiting premature differentiation. We also show that miR-92a and miR-92b directly target jigr1 in vivo and that some phenotypes due to the absence of these miRNAs are partially rescued by reducing the level of jigr1. These results reveal a novel function of the miR-92 family in Drosophila neuroblasts and provide another example that local negative feedback regulation of host genes by intragenic miRNAs is essential for animal development.     

Electrochemical based detection of microRNA, mir21 in breast cancer cells

Hemagglutinin (HA) is a trimeric glycoprotein expressed on the influenza virus membrane. HA of influenza viruses binds to the host's cell surface complex glycans via a terminal sialic acid (Sia), as the first key step in the process of infection, transmission and virulence of influenza viruses. It is important to monitor and evaluate the receptor (glycan) binding preferences of the HAs derived from influenza A viruses, especially those originating from birds and swine, to understand their potential ability for interspecies transmission. From this viewpoint, in the present study, we have developed a protocol for analyzing the glycan-HA interactions efficiently and kinetically, based on surface plasmon resonance (SPR). Our results showed that glycan-HA binding analyses can be performed reliably and efficiently on Biacore-chips in the SPR system, using chemically synthesized biotinylated multivalent-glycans. Using the CAP-chip, we were able to regenerate the surface for multiple analyses, allowing us to derive, for the first time, the precise kinetic parameters for different HA-glycan complexes of newly emerging influenza viruses. These studies suggested that this SPR-based method is suitable for influenza surveillance to define the pandemic scenario as well as to screen of synthetic glycans and other compounds that may interfere with glycan-HA interactions.     

Inducible nitric oxide synthase and apoptosis in human B cell lymphomas

Nitric oxide synthases are isoenzymes that catalyse the synthesis of nitric oxide (NO). NO plays both pathological and physiological roles depending on its rate of synthesis and concentration in cellular source and microenvironment. Apoptosis is an important biological factor in lymphomas. This study evaluates expression of inducible nitric oxide synthase (iNOS) in human lymphomas and its relation with apoptosis. This study comprised 46 cases of B-cell lymphoma. The lymphomas were classified as 3 mantle cell, 5 marginal zone, 4 follicular, 2 Burkitt, 25 diffuse large cell, 2 anaplastic large cell, 3 lymphoblastic, 2 lymphoplasmacytic according to WHO classification of lymphoid neoplasms. Hematoxylin eosin slides of the cases were reviewed and immunoperoxidase technique was performed iNOS and Caspase monoclonal antibodies to selected sections of each case. Antigen staining was carried out with iNOS and Caspase proteins and Ultravision Polyvalent, HRP-AEC kit (Neomarkers-Biogen USA). For the evaluation of iNOS and Caspase, tumor areas with a high density of expression were chosen. Positive stained cells were counted in 5 different areas at a magnification ×40 by an Olympus B × 51 microscope in each case. The iNOS and Caspase expressions were independently recorded by four pathologists and the results were averaged. All of the cases were positive for the iNOS and Caspase. But there is not a statistically important relation between lymphoma grade and iNOS activity. We could not find a correlation between iNOS and patients age. This study reveals the capacity of B-cell neoplasms to express iNOS in situ. In conclusion, our study revealed that there is a positive relation between iNOS expression and apoptosis (p $=$ 0.032 spearman correlation).     

Ghrelin is present in human colostrum, transitional and mature milk

Ghrelin and its mRNA have recently been found in numerous human tissues including breast. The aim of this study was to compare the ghrelin levels in colostrum, mature and transitional milk and plasma in lactating women with plasma samples from non-lactating women. Venous blood samples were obtained from 17 healthy lactating women aged 22-35 years and from 16 age-matched controls. Colostrum, transitional and mature milk samples were collected just before suckling. The level of bioactive ghrelin was determined by RIA. Comparison of ghrelin values for lactating women showed significantly lower concentrations in colostrum (70.3 +/- 18 pg/ml), transitional milk (83.8 +/- 18pg/ml) and mature milk (97.3 +/- 13 pg/ml) than in the corresponding plasma samples (first day 95 +/- 16 pg/ml, 10th day 111 +/- 13 pg/ml and 15th day 135 +/- 16 pg/ml). The plasma concentrations were lower in the lactating than in the non-lactating women. Thus, the ghrelin levels in colostrum, transitional and mature milk were elavated concomitantly with increasing plasma ghrelin after delivery. The origin of milk ghrelin is not known, but it probably comes from the plasma.     

Apolipoprotein B gene variants are involved in the determination of blood glucose and lipid levels in patients with non-insulin dependent diabetes mellitus

We have examined the frequency of the EcoRI, XbaI and MspI RFLPs of the apolipoprotein B (apo B) gene in 110 type 2 diabetic patients and 91 healthy control subjects in order to ascertain whether variation in this gene may influence the development of non-insulin dependent diabetes mellitus (type 2 diabetes). Serum lipids including total-cholesterol (T-Chol), triacylglycerol (TAG), apolipoprotein E (apo E), apolipoprotein AI (apo AI), apolipoprotein B and lipoprotein (a) (Lp(a)) were analysed. Genomic DNA was extracted and the apo B polymorphic regions amplified by the polymerase chain reaction. Regions carrying EcoRI, XbaI, and MspI restriction sites present in the apo B gene were amplified and digested separately by the respective enzymes. No significant difference for genotypic frequencies was observed for the EcoRI, XbaI and MspI restriction sites in type 2 diabetic patients as compared to controls. Type 2 diabetic patients and controls with EcoRI +/+ and XbaI +/+ genotypes had higher apo E levels. The MspI +/+ genotype is more frequent in the patient and control groups with elevated T-Chol. Furthermore, the EcoRI -/-, XbaI -/-, and MspI +/+ genotypes were found to be significantly more frequent in type 2 diabetic patients with higher blood glucose levels. This study identifies the apo B gene polymorphisms in modulating plasma lipid/lipoprotein and glucose levels in patients with type 2 diabetes.     

A new active compound from Centaurea species

The extract containing sesquiterpene lactones of Centaurea iberica (Asteraceae) isolated was separated and a steroidal compound, which is stigmast-1,5-dien-3beta-ol, was purified. The chemical structure was established based on spectroscopic data (UV, IR, MS, 1H NMR, 13C NMR). Both the extract and the compound showed significant antioxidant and antimicrobial activities.     

Blind Test of Physics-Based Prediction of Protein Structures

We report here a multiprotein blind test of a computer method to predict native protein structures based solely on an all-atom physics-based force field. We use the AMBER 96 potential function with an implicit (GB/SA) model of solvation, combined with replica-exchange molecular-dynamics simulations. Coarse conformational sampling is performed using the zipping and assembly method (ZAM), an approach that is designed to mimic the putative physical routes of protein folding. ZAM was applied to the folding of six proteins, from 76 to 112 monomers in length, in CASP7, a community-wide blind test of protein structure prediction. Because these predictions have about the same level of accuracy as typical bioinformatics methods, and do not utilize information from databases of known native structures, this work opens up the possibility of predicting the structures of membrane proteins, synthetic peptides, or other foldable polymers, for which there is little prior knowledge of native structures. This approach may also be useful for predicting physical protein folding routes, non-native conformations, and other physical properties from amino acid sequences.     

Clinical and electrophysiologic findings in dialysis patients

The aim of this study was to quantitatively determine the electrophysiologic changes occurring in the peripheral nerves and muscles in patients with chronic renal failure (CRF) treated with haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD), and to determine which electrophysiologic parameters are most commonly abnormal in uraemic patients. We investigated the relationship between the parameters of neurography and quantitative electromyography (QEMG) and clinical findings.The study included 42 patients with CRF (30 on HD and 12 on CAPD). Nerve conduction studies (NCSs) of the median, ulnar, tibial, peroneal, and sural nerves, and QEMG of the tibialis anterior and biceps brachii muscles were performed.We found axonal and/or demyelinating polyneuropathies in 97.6% of the patients (100% of HD and 91.7% of CAPD patients), but were not able to verify any significant differences between the HD and CAPD patients using NCS or QEMG. Median, ulnar, sural sensory nerve action potential (SNAP) amplitudes, peroneal CV and F-latency were the most common abnormal parameters in sensory and motor NCSs, respectively. The clinical findings only correlated with the parameters of neurography, and not with the parameters of QEMG. Sural SNAP amplitudes, peroneal and tibial CVs, F-latencies also correlated with the severity of the clinical findings in these patients, suggesting that these parameters can be used in follow up studies in these patients.In this study, most of the uraemic patients were found to have already mild or moderate neuropathies in which the objective clinical signs might be absent, even if they have some clinical symptoms. NCS showed abnormality indicating polyneuropathy in 24 out of 25 patients with clinical neuropathy signs and in 17 out of 17 patients with no clinical signs. Thus, in subclinical conditions NCS is useful to detect the abnormalities in peripheral nerves of the ureamic patients under chronic dialysis.     

Ghrelin and obestatin expression in oral squamous cell carcinoma: an immunohistochemical and biochemical study

The underlying molecular mechanism of carcinogenesis in oral squamous cell carcinoma (OSCC) is poorly understood and appears to be controlled on many genetic, environmental, and hormonal factors. Obestatin and ghrelin, two recently discovered hormones, are co-expressed in endocrine cells. The purpose of this investigation was to examine the immunohistochemical features of OSCCs in relation to the tissue concentration of ghrelin and obestatin. The association between OSCC and Epstein Barr Virus (EBV) status was also explored. The expression of ghrelin and obestatin was examined by immunohistochemistry and immunoassay in oral biopsy specimens: 10 benign squamous epithelial cell samples, 10 microinvasive squamous cell carcinomas, and seven well-differentiated and seven poorly differentiated OSCCs. The presence of EBV was evaluated in these samples using immunohistochemistry. The concentrations of ghrelin and obestatin in tissue homogenates were measured by RIA and ELISA, respectively. Squamous cell carcinomas and benign tissue samples were positive for anti-EBV antibody, and obestatin and ghrelin were shown to be co-expressed in all stratified squamous epithelium samples. Expression of ghrelin and obestatin was decreased or absent in OSCCs in relation to the invasiveness of the carcinoma; ghrelin and obestatin levels in cancerous tissue homogenates were lower than in benign tissue homogenates. These results indicate that the concentrations and distribution of immunoreactive obestatin and ghrelin might be helpful in distinguishing OSCC from benign tumors. Maintaining normal levels of these hormones might be required for regulation of normal cell division. However, detailed studies will be required for better understanding of the complex mechanism of carcinogenesis relating to OSCCs.