Variations in Chemical Composition,Vasorelaxant and Angiotensin I‐Converting Enzyme Inhibitory Activities of Essential Oil from Aerial Parts of Seseli pallasii Besser (Apiaceae)

The present paper describes environmental and seasonal‐related chemical composition variations, vasorelaxant and angiotensin I‐converting enzyme (ACE) activities of essential oil from aerial parts of Seseli pallasii Besser . The composition was analyzed by GC and GC/MS. Monoterpenes were found to be the most abundant chemical class with α ‐pinene (42.7 – 48.2%) as the most prevalent component. Seseli pallasi essential oil relaxed isolated endothelium‐intact mesenteric arteries rings precontracted with phenylephrine with IC ₅₀ = 3.10 nl/ml (IC ₅₀ = 2.70 μg/ml). Also, S. pallasii essential oil was found to exhibit a dose‐dependent ACE inhibitory activity with an IC ₅₀ value of 0.33 mg/ml. In silico evaluation of ACE inhibitory activity of the individual components showed that spathulenol exhibited the best binding affinity with ACE, and the lowest binding energy of ?7.5 kcal/mol. The results suggested that combination of vasorelaxing and ACE inhibitory effects of the analyzed S. pallasii essential oil might have the potential therapeutic significance in hypertension.     

ZO-1- and ZO-2-dependent integration of myosin-2 to epithelial zonula adherens

For the zonula adherens (ZA) to be established by linear arrangement of adherens junctions (AJs) in epithelial sheet cells, critical for the epithelial cell sheet formation and intercellular barrier function, myosin-2 is supposedly integrated into the ZA with the result of overlapping localization of E-cadherin/actin/myosin-2. Here, we immunofluorescently showed that myosin-2 failed to be integrated into the ZA in cultured epithelial-type ZO1(ko)/2(kd) Eph4 cells lacking ZO-1 and -2 (zonula occludens-1 and -2) by knockout and knockdown, respectively. Instead, a linearized but fragmented arrangement of AJs was formed in the way that it was positive for E-cadherin/actin, but negative for myosin-2 (designated prezonula-AJ). Transfection of full-length ZO-1 or ZO-2, or ZO-1 lacking its PDZ (PSD-95/discs large/zonula occludens-1)-1/2 domains (but not one lacking PDZ-1/2/3) into ZO1(ko)/2(kd) Eph4 cells restored the junctional integration of myosin-2 with prezonula-AJ to establish the ZA. Transfection of dominant-active RhoA or Rho-kinase (ROCK), as well as administration of lysophosphatidic acid or Y27632, which activates RhoA or inhibits ROCK, respectively, suggested that RhoA regulated the junctional integration of myosin-2 into ZA in a manner such that ROCK played a necessary but not-sufficient role. Fluorescence resonance energy transfer analyses revealed that spatiotemporal Rho-activation occurred in a ZO-1/2–dependent way to establish ZA from primordial forms in epithelial cells.     

The lipid raft-anchored adaptor protein Cbp controls the oncogenic potential of c-Src

The tyrosine kinase c-Src is upregulated in various human cancers irrespective of its negative regulator Csk, but the regulatory mechanisms remain unclear. Here, we show that a lipid raft-anchored Csk adaptor, Cbp/PAG, is directly involved in controlling the oncogenicity of c-Src. Using Csk-deficient cells that can be transformed by c-Src overexpression, we found that Cbp expression is markedly downregulated by c-Src activation and re-expression of Cbp efficiently suppresses c-Src transformation as well as tumorigenesis. Cbp-deficient cells are more susceptible to v-Src transformation than their parental cells. Upon phosphorylation, Cbp specifically binds to activated c-Src and sequesters it in lipid rafts, resulting in an efficient suppression of c-Src function independent of Csk. In some human cancer cells and tumors, Cbp is downregulated and the introduction of Cbp significantly suppresses tumorigenesis. These findings indicate a potential role for Cbp as a suppressor of c-Src-mediated tumor progression.     

Schistosoma mansoni: Effect of dietary zinc supplement on egg granuloma in Swiss mice treated with praziqantel

Schistosomiasis is one of the most important parasitic diseases in Egypt and chemotherapy is considered the most effective method of control. This study was conducted to assess the effectiveness of zinc administration against Schistosoma mansoni infection by evaluating the activities of arylesterase and paraoxonase (PON1) enzymes, and the degree of liver damage.One hundred and twenty albino mice were divided into two groups; one was an infected control and the other a treated group which was further subdivided into three according to the praziquantel and zinc supplementation given. Blood and liver samples, collected 10 weeks post-infection, were subjected to parasitological, histopathological, and enzyme assays, and immunological studies. The results showed that dietary zinc supplementation led to marked reduction in worm load, and egg deposition in the liver and intestine.Histopathological examination showed marked reduction in the number and diameter of hepatic granulomas in the treated groups. The activity of arylesterase and PON1 enzymes were partially restored in infected animals receiving zinc. IL-10 mRNA expression was higher in the treated groups than in the infection control group. In conclusion, zinc administration could be a promising adjuvant therapy for S. mansoni infection.     

Revisiting the planarity of nucleic acid bases: Pyramidilization at glycosidic nitrogen in purine bases is modulated by orientation of glycosidic torsion

We describe a novel, fundamental property of nucleobase structure, namely, pyramidilization at the N1/9 sites of purine and pyrimidine bases. Through a combined analyses of ultra-high-resolution X-ray structures of both oligonucleotides extracted from the Nucleic Acid Database and isolated nucleotides and nucleosides from the Cambridge Structural Database, together with a series of quantum chemical calculations, molecular dynamics (MD) simulations, and published solution nuclear magnetic resonance (NMR) data, we show that pyramidilization at the glycosidic nitrogen is an intrinsic property. This property is common to isolated nucleosides and nucleotides as well as oligonucleotides—it is also common to both RNA and DNA. Our analysis suggests that pyramidilization at N1/9 sites depends in a systematic way on the local structure of the nucleoside. Of note, the pyramidilization undergoes stereo-inversion upon reorientation of the glycosidic bond. The extent of the pyramidilization is further modulated by the conformation of the sugar ring. The observed pyramidilization is more pronounced for purine bases, while for pyrimidines it is negligible. We discuss how the assumption of nucleic acid base planarity can lead to systematic errors in determining the conformation of nucleotides from experimental data and from unconstrained MD simulations.     

Diacylglycerol Enrichment of Endoplasmic Reticulum or Lipid Droplets Recruits Perilipin 3/TIP47 during Lipid Storage and Mobilization

Fatty acid-induced triacylglycerol synthesis produces triacylglycerol droplets with a protein coat that includes perilipin 3/TIP47 and perilipin 4/S3-12. This study addresses the following two questions. Where do lipid droplets emerge, and how are their coat proteins recruited? We show that perilipin 3- and perilipin 4-coated lipid droplets emerge along the endoplasmic reticulum (ER). Blocking membrane trafficking with AlF₄⁻ during fatty acid-induced triacylglycerol synthesis drove perilipin 3 to the tubular ER. Forskolin, which like AlF₄⁻ activates adenylate cyclase, did not redistribute perilipin 3, but when added together with AlF₄⁻ perilipin 3 was recruited to lipid droplets rather than the ER. Thus inhibiting trafficking with AlF₄⁻ redistributed perilipin 3 differently under conditions of triacylglycerol synthesis (fatty acid addition) versus hydrolysis (forskolin) suggesting a shared acylglycerol-mediated mechanism. We tested whether diacylglycerol (DG), the immediate precursor of triacylglycerol and its first hydrolytic product, affects the distribution of perilipin 3. Stabilizing DG with the DG lipase inhibitor {"type":"entrez-protein","attrs":{"text":"RHC80267","term_id":"1470879788","term_text":"RHC80267"}}RHC80267 enhanced the perilipin 3 recruited to lipid droplets and raised DG levels in this fraction. Treating cells with a membrane-permeable DG recruited perilipin 3 to the ER. Stabilizing DG, by blocking its hydrolysis with {"type":"entrez-protein","attrs":{"text":"RHC80267","term_id":"1470879788","term_text":"RHC80267"}}RHC80267 or its acylation with triacsin C, enhanced recruitment of perilipin 3 to the ER. Expressing the ER enzyme DGAT1, which removes DG by converting it to triacylglycerol, attenuated perilipin 3 DG-induced ER recruitment. Membrane-permeable DG also drove perilipin 4 and 5 onto the ER. Together the data suggest that these lipid droplet proteins are recruited to DG-enriched membranes thereby linking lipid coat proteins to the metabolic state of the cell.     

Free and bound state structures of 6-O-methyl homoerythromycins and epitope mapping of their interactions with ribosomes

The solution and solid state conformations of several 6-O-methyl homoerythromycins 1–4 were studied using a combination of X-ray crystallography, NMR spectroscopy and molecular modelling calculations. In the solid state 1 was found to exist as the two independent molecules with similar structures termed 3-endo-folded-out. In solution a significant conformational flexibility was noticed especially in the C2 to C5 region. The compounds 1 and 2 unlike 14-membered macrolides adopted the 3-endo-folded-out conformation while 3 and 4 existed in the classical folded-out conformation. TrNOESY and STD experiments showed that 1 and 2 bound to the Escherichia coli ribosome while 3 and 4, lacking the cladinose sugar, did not exhibit binding activities, this being in accordance with biochemical data. The bound conformations were found to be very similar to the free ones, some small differences were observed and discussed. The STD experiments provided evidence on binding epitopes. The structural parts of 1 and 2 in close contact with ribosome were similar, however the degree of saturation transfer was higher for 2. The differences between tr-NOE data and STD enhancements in 1 and 2 arouse as a consequence of structural changes upon binding and a closer proximity of 2 to the ribosome surface. An understanding of the molecular mechanisms involved in the interaction of macrolides with ribosomes can help in developing strategies aiming at design of potential inhibitors.     

Hypoxia-inducible Factor-1-mediated Regulation of Semaphorin 4D Affects Tumor Growth and Vascularity

Tumor progression and metastasis depend on the ability of cancer cells to initiate angiogenesis to ensure delivery of oxygen, nutrients, and growth factors to tumor cells and provide access to the systemic circulation. Hypoxia-inducible factor-1 (HIF-1) can activate expression of a broad range of genes that mediate many of the adaptive responses to decreased oxygen concentration, such as enhanced glucose uptake and formation of new blood vessels. Acting through Plexin-B1 on endothelial cells, Semaphorin 4D (Sema4D) has been shown to promote angiogenesis and enhance invasive growth and proliferation in some tumors. Here we show that the gene for Sema4D, the product of which is elevated in head and neck squamous cell carcinoma (HNSCC) cells, contains upstream hypoxia response elements (HRE) and is strongly induced in hypoxia in a HIF-1-dependent manner. Knocking down Sema4D expression with short hairpin (sh) RNA reduces in vitro endothelial cell migration and growth and vascularity of HNSCC xenografts expressing a degradation resistant HIF-1α subunit. We also demonstrate a correlation between HIF-1 activity and Sema4D expression in HNSCC specimens. These findings indicate that Sema4D is induced by hypoxia in a HIF-1-dependent manner and influences endothelial cell migration and tumor vascularity. Expression of Sema4D may be a strategy by which carcinomas promote angiogenesis and therefore could represent a therapeutic target for these malignancies.     

Louse-borne bacterial pathogens in lice (Phthiraptera) of rodents and cattle from Egypt

We collected 1,023 lice, representing 5 species, from rats and domestic cattle throughout 13 governorates in Egypt and tested these lice for Anaplasma marginale, Bartonella spp., Brucella spp., Borrelia recurrentis, Coxiella burnetii, Francisella tularensis, and Rickettsia spp. by PCR amplification and sequencing. Five different louse-borne bacterial agents were detected in lice from rodents or cattle, including "Bartonella rattimassiliensis", "B. phoceensis", and Bartonella sp. near Bartonella tribocorum, Coxiella burnetii, and Rickettsia typhi. More lice from governorates bordering the Mediterranean and Red Seas contained pathogens. Our data indicate that lice of urban and domestic animals harbor pathogenic or potentially pathogenic bacterial agents throughout Egypt.