BdcA,a Protein Important for Escherichia coli Biofilm Dispersal,Is a Short-Chain Dehydrogenase/Reductase that Binds Specifically to NADPH

The Escherichia coli protein BdcA (previously referred to as YjgI) plays a key role in the dispersal of cells from bacterial biofilms, and its constitutive activation provides an attractive therapeutic target for dismantling these communities. In order to investigate the function of BdcA at a molecular level, we integrated structural and functional studies. Our 2.05 Å structure of BdcA shows that it is a member of the NAD(P)(H)-dependent short-chain dehydrogenase/reductase (SDR) superfamily. Structural comparisons with other members of the SDR family suggested that BdcA binds NADP(H). This was demonstrated experimentally using thermal denaturation studies, which showed that BcdA binds specifically to NADPH. Subsequent ITC experiments further confirmed this result and reported a K_d of 25.9 µM. Thus, BdcA represents the newest member of the limited number of oxidoreductases shown to be involved in quorum sensing and biofilm dispersal.     

Airborne Pollen Grains in Zonguldak,Turkey,2001-2002

The variation in airborne pollen concentration of the Zonguldak region, Turkey was studied for two consecutive years 2001-2002 using a Durham sampler. During this period, a total of 61 304 pollen grains belonging to 43 taxa were recorded. Of these 43 taxa, 26 belonged to arboreal and 17 to nonarboreal plants. The main pollen types were Pinaceae, Populus, Carpinus, Betula, Corylus, Fagus orientalis,Castanea sativa, Alnus glutinosa, Quercus, Cupressaceae, Chenopodiaceae and Gramineae, representing 96.7% of the pollen spectrum. Pollen concentration reached the highest level in March.     

Expression of glucose transporter 1 confers susceptibility to human T-cell leukemia virus envelope-mediated fusion

Human T-cell leukemia virus type 1 (HTLV-1) was the first human retrovirus identified and causes both adult T-cell leukemia/lymphoma and tropical spastic paraparesis/HTLV-1-associated myelopathy, among other disorders. In vitro, HTLV-1 has an extremely broad host cell tropism in that it is capable of infecting most mammalian cell types, although at the same time viral titers remain relatively low. Despite years of study, only recently has a bona fide candidate cellular receptor, glucose transporter 1 (glut-1), been identified. Although glut-1 was shown to bind specifically to the ectodomain of HTLV-1 and HTLV-2 envelope glycoproteins, which was reversible with small interfering RNA directed against glut-1, cellular susceptibility to HTLV upon expression of glut-1 was not established. Here we show that expression of glut-1 in relatively resistant MDBK cells conferred increased susceptibility to both HTLV-1- and HTLV-2-pseudotyped particles. glut-1 also markedly increased syncytium formation in MDBK cells after exposure to HTLV-1. Another assay also demonstrated HTLV-1 envelope-cell fusion in the presence of glut-1. Taken together, these results provide additional evidence that glut-1 is a receptor for HTLV.     

Restricted active site docking by enzyme-bound substrate enforces the ordered cleavage of prothrombin by prothrombinase

The preferred pathway for prothrombin activation by prothrombinase involves initial cleavage at Arg(320) to produce meizothrombin, which is then cleaved at Arg(271) to liberate thrombin. Exosite binding drives substrate affinity and is independent of the bond being cleaved. The pathway for cleavage is determined by large differences in V(max) for cleavage at the two sites within intact prothrombin. By fluorescence binding studies in the absence of catalysis, we have assessed the ability of the individual cleavage sites to engage the active site of Xa within prothrombinase at equilibrium. Using a panel of recombinant cleavage site mutants, we show that in intact prothrombin, the Arg(320) site effectively engages the active site in a 1:1 interaction between substrate and enzyme. In contrast, the Arg(271) site binds to the active site poorly in an interaction that is approximately 600-fold weaker. Perceived substrate affinity is independent of active site engagement by either cleavage site. We further show that prior cleavage at the 320 site or the stabilization of the uncleaved zymogen in a proteinase-like state facilitates efficient docking of Arg(271) at the active site of prothrombinase. Therefore, we establish direct relationships between docking of either cleavage site at the active site of the catalyst, the V(max) for cleavage at that site, substrate conformation, and the resulting pathway for prothrombin cleavage. Exosite tethering of the substrate in either the zymogen or proteinase conformation dictates which cleavage site can engage the active site of the catalyst and enforces the sequential cleavage of prothrombin by prothrombinase.     

Parazoanthus axinellae Extract Incorporated Hybrid Nanostructure and Its Potential Antimicrobial Activity**

This study, it was aimed to examine the change in the antimicrobial effect of sea anemone Parazoanthus axinellae extract by forming its nanoflowers. A scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) were expended to observe the morphologies of the Cu NFs that had been produced. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques were expended to analyze the managing assemblies in P. axinellae extract, which perform an effective part in the synthesis routine, as well as the crystal assembly of NFs. P. axinellae extract mediated the HNFs (Hybrid nanoflowers) are at high, pure crystalline nature, flower shape with a crystallographic system at the nanoscale with mean crystallite size 21.9 nm using XRD, and average particle size ~10 nm by SEM. The broad absorption band at 2981–2915 cm⁻¹ in the FT-IR spectra of anemone extract and Cu-anemone NFs represents the unique peak of hydroxy groups. In addition, Cu NFs were tested for their antibacterial properties. Cu NFs have been discovered to exhibit antibacterial properties. It is suggested that P. axinellae extract and various inorganic components be used to synthesize a variety of NFs and assess their suitability for usage in biomedical fields.     

PLCgamma participates in insulin stimulation of glucose uptake through activation of PKCzeta in brown adipocytes

Based on recent studies showing that PLCgamma associates to insulin receptor, we investigated its role in insulin stimulation of glucose transport in brown adipocytes. Insulin stimulation induced rapid PLCgamma association to phosphorylated insulin receptor, and activation of PLCgamma, as assessed by the mobilization of Ca(2+) from intracellular stores and by the production of the second messenger DAG. Both events are dependent on activation of PI3-kinase. Inhibition of PLCgamma activity either with the chemical compound U73122 or with an inhibitor peptide precluded insulin stimulation of glucose uptake, GLUT4 translocation, and actin reorganization, as wortmannin did. In contrast, the inactive analog U73343 did not have an inhibitory effect. Furthermore, translocation of GLUT4-GFP in response to insulin was completely abolished by cotransfection with a PLCgamma-inactive mutant in HeLa cells, a cell model sensitive to insulin that express PLCgamma. U73122 did not affect PI3-kinase nor Akt activation, but impaired PKCzeta activation by insulin, as wortmannin did. PLC activity renders two products, IP(3) and DAG, and DAG can be metabolized to PA by the action of DAG-kinase. Using the compound R54494, a DAG-kinase inhibitor, insulin-induced PKCzeta activation was also suppressed, this activity being restored by addition of PA. In summary, these data indicate that PLCgamma, activated at least partially by PI3-kinase, is a link between insulin receptor and PKCzeta through the production of PA and could mediate insulin-induced glucose uptake and GLUT4 translocation.     

A comparative study of cytotoxic, membrane and DNA damaging effects of Origanum majorana’s essential oil and its oxygenated monoterpene component linalool on parental and epirubicin-resistant H1299 cells

In this study, cytotoxic, membrane and DNA damaging effects of the essential oil from Origanum majorana and its oxygenated monoterpene component linalool were tested on parental and epirubicin-resistant (drug-resistant) human lung cancer cell lines (H1299). Essential oil’s and linalool’s cytotoxicities were examined and parental cells were found more sensitive to the essential oil’s and linalool’s cytotoxicities than drug-resistant cells. O. majorana essential oil had more effective membrane damaging effect than linalool on parental cells, while in drug-resistant H1299 cells, linalool had more effective membrane damaging effect than the essential oil. O. majorana essential oil possessed more effective DNA damaging effect than linalool on both parental and drug-resistant cells. The conclusions from this study suggest that O. majorana essential oil and linalool exhibit cytotoxic, membrane and DNA damaging effects. They thus need further investigation as potential therapeutic agents for human lung cancer.     

Developing a Valuation Function for the Preference-Based Multiple Sclerosis Index: Comparison of Standard Gamble and Rating Scale

ObjectiveThe standard gamble (SG) and rating scale (RS) are two approaches that can be employed to elicit health state preferences from patients in order to inform decision making. The objectives of this study were: (i) to contribute evidence towards the similarities and differences in the SG and the RS to reflect patient preferences, and (ii) to develop a multi-attribute utility function (MAUF) (i.e., scoring algorithm) for the PBMSI.ResultsThe mean RS values ranged from 0.39 to 0.65, whereas the mean SG values were much higher ranging from 0.80 to 0.91. Correlations between the two methods were very low ranging from -0.29 to 0.15. Bland-Altman plots revealed the extent of differences in values produced by the two methods.ConclusionIn contemplating trade-offs in the selection of a preference-based elicitation approach for a MAUF that could guide clinical decision making, results suggest the RS is preferable in terms of feasibility and validity for MS patients. The PBMSI with patient preferences shows promise as a measure of health-related quality of life for MS.