Identification and quantitation of usnic acid from the lichen Usnea species of Anatolia and antimicrobial activity

Six species of lichens, such as Usnea florida, Usnea barbata, Usnea longissima, Usnea rigida, Usnea hirta and Usnea subflorida, were collected from different areas of Anatolia (district of Antalya, Karabük, Qankiri, Giresun and Trabzon) in Turkey. Their usnic acid amounts in acetone extracts were determined by HPLC. In addition, antimicrobial activities of these extracts were determined against Escherichia coli (ATCC 35218), Enterococcus faecalis (RSKK 508), Proteus mirabilis (Pasteur Ens. 235), Staphylococcus aureus, Bacillus subtilis and Bacillus megaterium. It was shown that with increasing amount of usnic acid, the antimicrobial activity increased. Usnic acid contents of Usnea species varied between 0.22-6.49% of dry weight.     

NMR structures of the selenoproteins Sep15 and SelM reveal redox activity of a new thioredoxin-like family

Selenium has significant health benefits, including potent cancer prevention activity and roles in immune function and the male reproductive system. Selenium-containing proteins, which incorporate this essential micronutrient as selenocysteine, are proposed to mediate the positive effects of dietary selenium. Presented here are the solution NMR structures of the selenoprotein SelM and an ortholog of the selenoprotein Sep15. These data reveal that Sep15 and SelM are structural homologs that establish a new thioredoxin-like protein family. The location of the active-site redox motifs within the fold together with the observed localized conformational changes after thiol-disulfide exchange and measured redox potential indicate that they have redox activity. In mammals, Sep15 expression is regulated by dietary selenium, and either decreased or increased expression of this selenoprotein alters redox homeostasis. A physiological role for Sep15 and SelM as thiol-disulfide oxidoreductases and their contribution to the quality control pathways of the endoplasmic reticulum are discussed.     

Distinctive communication networks in inactive states of β2-adrenergic receptor: Mutual information and entropy transfer analysis

Mutual information and entropy transfer analysis employed on two inactive states of human beta-2 adrenergic receptor (β₂-AR) unraveled distinct communication pathways. Previously, a so-called “highly” inactive state of the receptor was observed during 1.5 microsecond long molecular dynamics simulation where the largest intracellular loop (ICL3) was swiftly packed onto the G-protein binding cavity, becoming entirely inaccessible. Mutual information quantifying the degree of correspondence between backbone-C_α fluctuations was mostly shared between intra- and extra-cellular loop regions in the original inactive state, but shifted to entirely different regions in this latest inactive state. Interestingly, the largest amount of mutual information was always shared among the mobile regions. Irrespective of the conformational state, polar residues always contributed more to mutual information than hydrophobic residues, and also the number of polar-polar residue pairs shared the highest degree of mutual information compared to those incorporating hydrophobic residues. Entropy transfer, quantifying the correspondence between backbone-C_α fluctuations at different timesteps, revealed a distinctive pathway directed from the extracellular site toward intracellular portions in this recently exposed inactive state for which the direction of information flow was the reverse of that observed in the original inactive state where the mobile ICL3 and its intracellular surroundings drove the future fluctuations of extracellular regions.     

The Glc7 phosphatase subunit of the cleavage and polyadenylation factor is essential for transcription termination on snoRNA genes

Glc7, the yeast protein phosphatase 1, is a component of the cleavage and polyadenylation factor (CPF). Here we show that downregulation of Glc7, or its dissociation from CPF in the absence of CPF subunits Ref2 or Swd2, results in similar snoRNA termination defects. Overexpressing a C-terminal fragment of Sen1, a superfamily I helicase required for snoRNA termination, suppresses the growth and termination defects associated with loss of Swd2 or Ref2, but not Glc7. Suppression by Sen1 requires nuclear localization and direct interaction with Glc7, which can dephosphorylate Sen1 in vitro. The suppressing fragment, and in a similar manner full-length Sen1, copurifies with the snoRNA termination factors Nrd1 and Nab3, suggesting loss of Glc7 from CPF can be compensated by recruiting Glc7 to Nrd1-Nab3 through Sen1. Swd2 is also a subunit of the Set1c histone H3K4 methyltransferase complex and is required for its stability and optimal methyltransferase activity.     

Seroprevalence of Borrelia burgdorferi infection among forestry workers and farmers in Duzce, north-western Turkey

Borrelia burgdorferi infection is the most frequent tick-transmitted disease worldwide. Our aim was to assess the seroprevalence of B. burgdorferi infection among forestry workers and farmers in Duzce, in the north-west region of Turkey. Blood samples from 349 forestry workers and farmers and 193 healthy blood donors were obtained to determine the presence of antibodies to B. burgdorferi. A two-step testing strategy was used; the sera were initially tested by ELISA and then by Western blot (WB) IgG. Demographic data regarding residence, age, gender, profession, tick bite history, contact with animals, and symptoms involving the skin, nervous system, and osteoarticular system were collected by questionnaire. All results were evaluated statistically using the chi2 test. The seroprevalence of B. burgdorferi was 10.9% (n=38) in forestry workers and farmers and 2.6% (n=5) in blood donors by ELISA, with a statistically significant difference (p<0.001). Seropositivity rates were related to age, gender, and common risk factors for the disease. IgG seropositivity was confirmed in four (1.1%) sera by WB. In this first seroepidemiological report from the northwest region of Turkey, tick bite exposure was found to be high, whereas B. burgdorferi infection was not common. Preventive measures against tick exposure and further studies to determine the distribution of Lyme disease in Turkey are proposed.     

Effect of Thiolated Polymers to Textural and Mucoadhesive Properties of Vaginal Gel Formulations Prepared with Polycarbophil and Chitosan

The aim of this study was to design and evaluate of mucoadhesive gel formulations for the vaginal application of clomiphene citrate (CLM) for local treatment of human papilloma virus (HPV) infections. Chitosan (CHI) and polycarbophil (PC) were covalently modified using the thioglycolic acid and L-cysteine, respectively. The formation of thiol conjugates of chitosan (CHI-TG) and polycarbophil (PC-CYS) were confirmed by FT-IR analysis and PC-CYS and CHI-TG were found to have 148.42 ± 4.16 and 41.17 ± 2.34 μmol of thiol groups per gram of polymer, respectively. One percent CLM gels were prepared by combination of various concentrations of PC and CHI with thiolated conjugates of these polymers. Hardness, compressibility, elasticity, adhesiveness and cohesiveness of the gels were measured by Texture profile analysis and the vaginal mucoadhesion was investigated by mucoadhesion test. The increasing in the amount of the thiol conjugates was found to enhance the elasticity, cohesiveness, adhesiveness and mucoadhesion of the gel formulations but not their hardness and compressibility when compared to gels prepared using their respective parent formulations. Slower release rate of CLM from gels was achieved when the polymer concentrations were increased in the gel formulations. PC and its thiol conjugate were found to prolong the release of CLM longer than 70 h unlike gel formulations prepared using CHI and its thiol conjugate which were able to release CLM up to 12 h. Stability of CLM was preserved during the 3 month stability analysis under controlled room temperature and accelerated conditions.     

Anaerobic Biodegradation of Poly-3-Hydroxybutyrate (PHB) by Sulfate Reducing Bacterium Desulfotomaculum sp.

Poly-3-hydroxybutyrate (PHB) film pieces were degraded by sulfate reducing Desulfotomaculum sp. incubated under anaerobic laboratory conditions. Degradation started with adherence of the microbial cells and followed by formation of black colonies on the film surface. Scanning electron microscopic (SEM) observations revealed the presence of bacteria and formation of small holes on the film. After 60 days of incubation at 30°C, 10 % weight loss in polymer and 13 % sulfate reduction in the medium was observed. According to gel permeation chromatography (GPC) analysis, the molecular weight of the PHB decreased after 30 days and did not decrease further at a more extended incubation period. Loss of weight of PHB does not seem to be correlated with molecular weight decrease.     

Electronic Excited States of the CP29 Antenna Complex of Green Plants: A Model Based on Exciton Calculations

We have suggested a model for the electronic excited states of the minorplant antenna, CP29, by incorporating a considerable part of the currentinformation offered by structure determination, site-directed mutagenesis,and spectroscopy in the modeling.We have assumed that the electronic excited states of the complex havebeen decided by the chlorophyll-chlorophyll (Chl) and Chl-proteininteractions and have modeled the Coulombic interaction between a pairof Chls in the point-dipole approximation and the Chl-protein interactionsare treated as empirical fit parameters.We have suggested the Q_y dipole moment orientations and the siteenergies for all the chlorophylls in the complex through a simultaneoussimulation of the absorption and linear dichroism spectra.The assignments proposed have been discussed to yield a satisfactoryreproduction of all prominent features of the absorption, linear and circulardichroism spectra as well as the key spectral and temporal characteristics ofthe energy transfer processes among the chlorophylls.The orientations and the spectral assignments obtained by relatively simpleexciton calculations have been necessary to provide a good point ofdeparture for more detailed treatments of structure-function relationship inCP29. Moreover, it has been discussed that the CP29 model suggested canguide the studies for a better understanding of the structure-functionrelationship in the major plant antenna, LHCII.     

<Emphasis Type="Italic">Nonomuraea insulae</Emphasis> sp. nov., isolated from forest soil

Strain H2R21^T, a novel actinobacterium, isolated from a forest soil sample collected from Heybeliada, Istanbul, Turkey, and a polyphasic approach was used for characterisation of the strain. Chemotaxonomic and morphological characterisation of strain H2R21^T indicated that it belongs to the genus Nonomuraea. 16S rRNA gene sequence similarity showed that the strain is closely related to Nonomuraea purpurea 1SM4-01^T (99.1%) and Nonomuraea solani CGMCC 4.7037^T (98.4%). DNA–DNA relatedness values were found to be lower than 70% between the isolate and its phylogenetic neighbours N. purpurea 1SM4-01^T, N. solani CGMCC 4.7037^T and Nonomuraea rhizophila YIM 67092^T. The whole cell hydrolysates of strain H2R21^T were found to contain meso-diaminopimelic acid as the diagnostic diamino acid and glucose, madurose, mannose and ribose as the cell sugars. The polar lipids were identified as phosphatidylglycerol, diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, dihydroxy-phosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, two glycophospholipids and two unidentified lipids. The predominant menaquinones were identified as MK-9(H₄) and MK-9(H₆). The major fatty acids were found to be iso-C_16:0, iso-C_16:0 2OH and C_17:0 10-methyl. On the basis of DNA–DNA relatedness data and some phenotypic characteristics, it is evident that strain H2R21^T can be distinguished from the closely related species in the genus Nonomuraea. Thus, it is concluded that strain H2R21^T represents a novel species of the genus Nonomuraea, for which the name Nonomuraea insulae sp. nov. is proposed. The type strain is H2R21^T (= DSM 102915^T = CGMCC 4.7338^T = KCTC 39769^T).