SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Zeitschrift fur Naturforschung. C, Journal of biosciences

22

Virus-induced gene silencing (VIGS) is an effective strategy for rapid gene function analysis. It is well established that the NAC transcription factor and salicylic acid (SA) signal pathway play essential roles in response to biotic stresses. However, simultaneous silencing of two target genes using VIGS in plants has been rarely reported. Therefore, in this report, we performed VIGS to silence simultaneously the SA-binding protein 2 (NbSABP2) and NbNAC1 in Nicotiana benthamiana to investigate the gene silencing efficiency of simultaneous silencing of two genes. We first cloned the full-length NbNAC1 gene, and the characterization of NbNAC1 was also analysed. Overlap extension polymerase chain reaction (PCR) analysis showed that the combination of NbSABP2 and NbNAC1 was successfully amplified. Bacteria liquid PCR confirmed that the combination of NbSABP2 and NbNAC1 was successfully inserted into the tobacco rattle virus vector. The results showed that the leaves from the NbSABP2 and NbNAC1 gene-silenced plants collapsed slightly, with browning at the base of petiole or veina. Quantitative real-time PCR results showed that the expression of NbSABP2 and NbNAC1 were significantly reduced in 12 days post silenced plants after tobacco rattle virus infiltration compared with the control plants. Overall, our results suggest that VIGS can be used to silence simultaneously two target genes.

22

The antibacterial-guided investigation of the stem bark extract of Pseudocedrela kotschyi led to the isolation of a new secotirucallane triterpene derivative: 4-hydroxy-3,4-secotirucalla-7,24-dien-3,21-dioic acid (1), together with the known one: 3,4-secotirucalla-4(28),7,24-trien-3,21-dioic acid (2) and 3-methyl ester 3,4-secotirucalla-4(28),7,24-trien-3,21-dioic (3). The structures of the isolated compounds were elucidated on the basis of extensive 1D- and 2D-NMR spectroscopy. Extracts, fractions and compounds (1-3) were tested in vitro for antibacterial activity against two Gram positive bacteria (Bacillus subtilis and Staphylococcus aureus ATCC 25923), and two Gram negative bacteria (Escherichia coli S2(1) and Pseudomonas aeruginosa). The MeOH extract and the Hex/CH2Cl2 (70:30) fraction showed significant levels of activity (MIC=64- 256 μg/mL) compared with the two reference drugs [ciprofloxacin: MIC (0.5-1 μg/mL) and amoxicillin: MIC (1-128 μg/mL)]. Moreover, the compound 2 isolated from this Hex/CH2Cl2 (70:30) fraction had the greatest potential value against S. aureus, E. coli and P. aeruginosa, with minimum inhibitory concentrations (MIC) ranging from 4-16 μg/mL.

Concepts: Bacteria, Microbiology, Antibiotic resistance, Escherichia coli, Pseudomonas aeruginosa, Gram negative bacteria, Gram-negative bacteria, Gram-positive bacteria

22

Lavandula stoechas subsp. stoechas and Mentha spicata subsp. spicata are used for the treatment of sinusitis in Turkish folk medicine. The components of essential oils obtained by hydrodistillation were determined by gas chromatography-flame ionization detector (GC-FID), gas chromatography/mass spectrometry (GC/MS), and thin layer chromatography (TLC). Major components of L. stoechas and M. spicata oils were determined as camphor (46.7%) and carvone (60.6%), respectively. The antibacterial activity of essential oils and their main components were tested against the common selected sinusitis pathogens Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, and Pseudomonas aeruginosa using in vitro agar diffusion, microdilution, and vapor diffusion methods. As a result, the tested plant materials, which are locally and natively used against sinusitis, were relatively mild antibacterial (in vitro MICs 310-1250 μg/mL) in action. To use essential oils and their components safely in sinusitis therapy, further detailed in vivo experiments are needed to support their efficacy.

Concepts: Bacteria, Pneumonia, Streptococcus pneumoniae, Chromatography, Haemophilus influenzae, Essential oil, Thin layer chromatography, Lavender

0

An ultra-high-performance liquid chromatography - high-resolution mass spectrometry profiling method was used for a comprehensive study of flavonoid and saponin-rich fractions from the aerial parts of wild spinach (Chenopodium bonus-henricus L.). Thirty-six compounds, respectively, 22 saponins of eight sapogenins (phytolaccagenin, bayogenin, medicagenic acid, 2β-hydroxygypsogenin, 2β-hydroxyoleanoic acid, 2-hydroxy-30-nor-gypsogenin, 2-hydroxyakebonic acid, and akebonic acid) together with 12 flavonoid glycosides of 6-methoxykaempferol, isorhamnetin, patuletin, spinacetin as well as two ecdysteroids (20-hydroxyecdysone and polypodine B) were detected. The occurrence of sapogenins 2-hydroxy-30-nor-gypsogenin, 2-hydroxyakebonic acid, and akebonic acid in the Chenopodium genus is reported here for the first time. The flavonoid and saponin-rich fractions showed in vitro hepatoprotective and antioxidant activity comparable to those of flavonoid complex silymarin (60 μg/mL) in a model of metabolic bioactivation, induced by CCl4. All tested fractions, compared to silymarin, significantly reduced the cellular damage caused by CCl4 in rat hepatocytes, preserved cell viability and GSH level, decreased LDH leakage, and reduced lipid damage. The results showed that saponin-rich fractions F3A and F3B possessed better hepatoprotective activity than flavonoid-rich fractions (F2A and F2B). The most active was fraction F3B and this is probably due to the synergism between the saponins and some acylated flavonol glycosides found there.

0

Since tyrosine phosphorylation appears to play important functions in photoreceptor cells, we searched here for retinal nonreceptor tyrosine kinases of the Src family. We demonstrated that Src family tyrosine kinases were present in the cytosolic fraction of extracted bovine retinas. A Src family tyrosine kinase with an apparent molecular mass of about 62 kDa was purified to homogeneity from the soluble fraction of dark-adapted bovine retinas after three consecutive purification steps: ω-aminooctyl-agarose hydrophobic chromatography, Cibacron blue 3GA-agarose pseudo-affinity chromatography, and α-casein-agarose affinity chromatography. The purified protein was subjected to N-terminal amino acid sequencing and the sequence Gly-Ile-Ile-Lys-Ser-Glu-Glu was obtained, which displayed homology with the first seven residues of the Src family tyrosine kinase c-Yes from Bos taurus (Gly-Cys-Ile-Lys-Ser-Lys-Glu). Although the cytosolic fraction from dark-adapted retinas contained tyrosine kinases of the Src family capable of phosphorylating the α-subunit of transducin, which is the heterotrimeric G protein involved in phototransduction, the purified tyrosine kinase was not capable of using transducin as a substrate. The cellular role of this retinal Src family member remains to be found.

0

Combination of various compounds and essential oils for pharmaceutical formulations withdraw attention. In this present study, it was aimed to evaluate the in vitro potential synergistic antibacterial effect of Lavandula latifolia (spike lavender) essential oil with camphor by using the checkerboard method against the human pathogens; Staphylococcus aureus and Listeria monocytogenes. Pharmacopoeia quality L. latifolia essential oil and racemic camphor were analyzed and verified by GC-FID and GC/MS, simultaneously. In vitro antibacterial activity of essential oil and camphor (MIC range: 0.16-20 mg/mL) and standard antimicrobial clarithromycin (MIC range: 0.125-16 μg/mL) were carried out by broth microdilution against S. aureus and L. monocytogenes standard strains, respectively. Resulting antibacterial effects were evaluated for their fractional inhibitory concentrations (FICs) as antagonistic, additive and synergistic effects. The analytical results showed that the major component of essential oil was linalool (45.2%) and 1,8-cineole (25.6%). Antibacterial effects of essential oil were determined as MIC 1.25-5 mg/mL. As a result of the experiments, L. latifolia essential oil-camphor combinations were identified as “synergistic (FIC ≤ 0.5), and additive (0.5 < FIC ≤ 1)" in the respective combinations, suggesting further evaluation for formulations for potential antimicrobial applications in food and pharmaceuticals.

0

Natural compound tetrandrine was reported to inhibit the proliferation of T cells by inhibiting activation of NF-κB. Chemically, isotetrandrine differs from tetrandrine only in the stereochemistry at the chiral centers. The present study aimed to compare their anti-proliferation effects on human T cells with a focus on NF-κB. The IC50 values of tetrandrine against MOLT-4 cells, MOLT-4/DNR cells, and concanavalin A-activated peripheral blood mononuclear cells of healthy subjects and dialysis patients were 4.43 ± 0.22, 3.62 ± 0.22, 1.91 ± 0.22 and 3.03 ± 0.28 μM, respectively. Whereas, the IC50 values of isotetrandrine against the above immune cells were 2.19 ± 0.27, 2.28 ± 0.33, 1.29 ± 0.14 and 1.55 ± 0.26 μM, respectively. The inhibitory effect of isotetrandrine against the proliferation of T cells was stronger than that of tetrandrine significantly (p < 0.05). Molecular mechanism investigation showed that 10 μM of isotetrandrine largely decreased the expression of p-NF-κB and NF-κB in both MOLT-4 and MOLT-4/DNR T cells (p < 0.05), whereas 10 μM of tetrandrine slightly inhibited the phosphorylation of p-NF-κB with little influence on the expression of NF-κB. Taken together, absolute configurations of tetrandrine and isotetrandrine are suggested to influence on their anti-proliferation effects in human T cells via different regulation of NF-κB.

0

Two new lignans, 3,4-(10-methoxy-phenylallyl)-9″-((10'-isopropanol-3',4'-furan)-phenylacetyl)-8″-dioxane-7″-O-β-d-glucopyranoside (1), 3,4-benzolactone-9″-((12'-isopropanol-3',4'-furan)-phenylbutenone)-8″-dioxane-7″-O-β-d-glucopyranoside (2), and nine known lignan derivatives (3-11) were isolated from the flower buds of Magnolia biondii Pamp. for the first time. Their structures were elucidated by 1D and 2D NMR, UV, IR, and MS data, as well as by comparison with those of the references. Compounds (1-11) were evaluated for their neuroprotective activities against 6-OHDA-induced cell death in SH-SY5Y cells. As a result, compounds 1, 2, and 5 exhibited significant neuroprotective activities with IC50 values in the range of 3.08-6.12 μM.

0

The fruits of Elaeocarpus floribundus Bl. (Elaeocarpaceae) are edible and are normally prescribed for treatment of diseases. The medicinal uses of the fruit create considerable quantities of seeds as wastes. In an attempt to valorise this biomass, we studied the antimicrobial and antioxidant activities of the ethanolic seed extract. The extract inhibited the growth of the tested pathogens and was also a very strong scavenger of DPPH free radicals. Consequently, the extract was phytochemically investigated and this study reports the initial isolation of five phenolic compounds from this source. The structures of the isolated compounds were elucidated by spectra analyses including HR-ESI-MS, 1D and 2D NMR experiments. The isolated compounds exhibited a wide range of antimicrobial activities against the tested pathogens. Gallic acid (4) showed the most activity against Bacillus subtilis with a minimum inhibitory concentration (MIC) value of 30 µg/mL, while the MIC values of the antimicrobial standards range between 10 and 35 µg/mL. Compound 4, crude ethanolic extract, and the ethyl acetate fraction were more a potent free radical scavenger of DPPH compared to ascorbic acid. Hence, the seeds of E. floribundus could be considered as a new source of bioactive compounds for pharmaceutical and food-related industries.

0

Root of Chrysopogon zizanioides (L.) Roberty has been used in Siddha system of medicine to treat hypertension. The present study was therefore to investigate the vasorelaxation effect of root essential oil of C. zizanioides using rat isolated thoracic aortic rings. Chemical characterization of root essential oil was carried out using Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS). Essential oil nanoemulsion (EONE) was prepared and characterized. Vasorelaxant effect of EONE in endothelium-intact aortic rings precontracted with phenylephrine (PE) (1 µM) or KCl (80 mM) was investigated. Role of Ca2+, nitric oxide and K+ channels in precontracted aortic rings were investigated to elucidate the mechanism of action of the essential oil. Further, the role of muscarinic and prostacyclin receptors in EONE induced relaxation was studied. The EONE significantly induced relaxation (Emax 77.1 ± 4.87%) in PE precontracted aortic rings. The nitric oxide synthase, and cyclooxygenase inhibitors and potassium channel blockers have not significantly inhibited the vasorelaxation induced by EONE. However, EONE induced relaxation in precontracted endothelium-intact aortic rings was significantly inhibited by muscarinic receptor and calcium channel. The root essential oil of C. zizanioides possesses vasorelaxant effect through muscarinic pathway as well as acts as calcium channel blocker.