93 research outputs found
Overexpressing temperature-sensitive dynamin decelerates phototransduction and bundles microtubules in drosophila photoreceptors
shibire(ts1), a temperature-sensitive mutation of the Drosophila gene encoding a Dynamin orthologue, blocks vesicle endocytosis and thus synaptic transmission, at elevated, or restrictive temperatures. By targeted Gal4 expression, UAS-shibire(ts1) has been used to dissect neuronal circuits. We investigated the effects of UAS-shibire(ts1) overexpression in Drosophila photoreceptors at permissive (19 degrees C) and restrictive (31 degrees C) temperatures. At 19 degrees C, overexpression of UAS-shi(ts1) causes decelerated phototransduction and reduced neurotransmitter release. This phenotype is exacerbated with dark adaptation, age and in white mutants. Photoreceptors overexpressing UAS-shibire(ts1) contain terminals with widespread vacuolated mitochondria, reduced numbers of vesicles and bundled microtubules. Immuno-electron microscopy reveals that the latter are dynamin coated. Further, the microtubule phenotype is not restricted to photoreceptors, as UAS-shibire(ts1) overexpression in lamina cells also bundles microtubules. We conclude that dynamin has multiple functions that are interrupted by UAS-shibire(ts1) overexpression in Drosophila photoreceptors, destabilizing their neural communication irreversibly at previously reported permissive temperatures
Deposition of polymeric thin films from propane-butane in atmospheric pressure discharge
In our experimental work we prepared thin films via plasma polymerisation and characterized them. These films were prepared on a glass substrate in the dielectric barrier discharge (BDB). The wettability of the deposited layers was determined by measuring of the contact angle and the free surface energy of the layers using the SEE system apparatus. The atomic composition and the surface morphology of the thin layers was characterized by scanning electron microscopy (SEM). Performed biological tests of biocompatibility and antibacterial properties provided information on the viability of the cells on the layers and their antibacterial effects
Morphological Changes in the Hepatic Tissue at the Impact of Industrial Copper-bearing Dust in the Experiment
BACKGROUND: It is known that an increased intake of copper (Cu) has an adverse effect, and above all leads to the defeat of parenchymal organs, including liver tissue.
AIM: This study the morphological changes in the hepatic tissue at the impact of polymetallic Cu dust.
METHODS: An experimental study was carried out on the outbred white male rats. Dust was injected once intratracheally at a dose of 50 mg. For dynamic observation, the animals were killed in 1, 3, and 6 months with the control group using instant decapitation. The Balkhash industrial polymetallic dust with a predominant Cu content (Cu-0.6%) was used for the study. Morphological changes were assessed using histological and morphometric methods.
RESULTS: Morphometric examination of liver tissue at 30 days showed Vv necrosis increasing in 320 times in Group 2 (p < 0.001), Vv infiltrates – in 121 times (p < 0.001), Vv dystrophic altered hepatocytes – in 19.91 times (p < 0.001), Vv dual-core cells – in 23 times (p < 0.01), and Vv fibrosis – in 2.82 times (p < 0.001) in comparison with Group 1. Vv portal tracts are not reliably changed. In 90 days, there were also the following morphometric parameters increasing in comparison with the control group: Vv necrosis – in 522 times (p < 0.001), Vv infiltrates – in 395 times (p < 0.001), Vv dystrophic altered hepatocytes – in 26.7 times (p < 0.001), Vv dual-core cells – in 314 times (p < 0.01), and Vv fibrosis – in 13.27 times (p < 0.001). On the 180 day of the experiment, there was the increasing of Vv infiltrates in 421 times (p < 0.001), Vv dystrophic altered hepatocytes – in 34.09 times (p < 0.001), Vv dual-core cells – in 411 times (p < 0.001), and Vv fibrosis – in 54.09 times (p < 0.001)
CONCLUSION: The impact of polymetallic dust with 0.6% Cu concentration at the early stages leads to the changes in the liver in the form of reactive hepatitis with the following transformation into portal-type hepatitis
Electrochemical Aptasensor Based on a Macrocyclic Ligand Bearing Neutral Red
An amperometric aptasensor has been developed by immobilization of DNA aptamer with Neutral Red (NR) on polycarboxylated thiacalix[4]arene onto the electropolymerized NR layer at a glassy carbon electrode. The NR reduction current recorded after 10min incubation decayed with increased thrombin concentration due to limitation of the electron exchange in the surface layer. The aptasensor makes it possible to determine 0.1-50nM of thrombin (limit of detection 0.05nM). The aptasensor can be used for the direct determination of thrombin in blood serum and does not exert any alteration of the response in the presence of 100 fold excess of serum proteins. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Label-free aptasensor for thrombin determination based on the nanostructured phenazine mediator
New aptasensors based on DNA aptamer and polycarboxylated thiacalix[4]arenes in cone, 1,3-alternate and partial cone configurations bearing Neutral Red (NR) at substituents at the lower rim have been developed and applied for thrombin detection. The assembly of the biorecognition layer was optimized by AFM and EIS study to reach the maximal coverage and regular composition of the surface layer. The interaction of the NR groups with thrombin suppressed the electron hopping between oxidized and reduced mediator groups. This regularly decreased the NR peak current and increased the resistance of the charge transfer. The aptasensor makes it possible to detect from 1 nM to 1 μM of thrombin with the detection limit of 0.05-0.5 nM. No effect of the 1000 excess of bovine serum albumin on the signal was observed. The influence of thiacalix[4]arene configuration on the sensitivity of aptasensor signal toward thrombin is discussed. © 2012 Elsevier B.V. All rights reserved
The H states studied in the reaction and evidence of extremely correlated character of the H ground state
The extremely neutron-rich system H was studied in the direct
H transfer reaction with a 26
MeV secondary He beam. The measured missing mass spectrum shows a
resonant state in H at MeV relative to the H+ threshold.
The population cross section of the presumably -wave states in the energy
range from 4 to 8 MeV is
b/sr in the angular range . The
obtained missing mass spectrum is free of the H events below 3.5 MeV
( b/sr in the same angular
range). The steep rise of the H missing mass spectrum at 3 MeV allows to
show that MeV is the lower limit for the possible resonant state
energy in H tolerated by our data. According to paring energy estimates,
such a MeV resonance is a realistic candidate for the H ground
state (g.s.). The obtained results confirm that the decay mechanism of the
H g.s.\ (located at 2.2 MeV above the H+ threshold) is the
``true'' (or simultaneous) emission. The resonance energy profiles and the
momentum distributions of the sequential H \,\rightarrow \,
^5H(g.s.)+n\, \rightarrow \, ^3H+ decay fragments were analyzed by the
theoretically-updated direct four-body-decay and sequential-emission
mechanisms. The measured momentum distributions of the H fragments in the
H rest frame indicate very strong ``dineutron-type'' correlations in the
H ground state decay.Comment: 9 pages, 11 figure
Study of Proton and Deuteron Pickup Reactions 2H(10Be,3He)9Li an 2H(10Be,4He)8Li with 44 A MeV 10Be Radioactive Beam at ACCULINNA-2 Fragment Separator
The proton and deuteron pickup reactions 2H(10Be,3He)9Li and\\
2H(10Be,4He)8Li radioactive beam produced by the new fragment separator
ACCULINNA-2 at FLNR, JINR\@. These measurements were initially motivated as
test reactions intended for the elucidation of results obtained in the study of
the extremely neutron-rich 7H and 6H systems created in the 2H(10Be,3He)9Li and
2H(10Be,4He)8Li reactions using the same setup. In the 2H(10Be,3He)9Li reaction
the 9Li ground-state () and its first excited state (2.69~MeV, )
were identified in the low-energy region of its excitation spectrum. The
differential cross sections for the 9Li g.~s.) population were extracted at
forward center-of-mass angles () and compared with the FRESCO
calculations. Spectroscopic factor of , derived by a model for the
10Be9Li(g.s.) clustering was found in accord with the experimental
data. The energy spectrum of 8Li populated in the 2H(10Be,4He)8Li reaction
shows the strong peak which corresponds to excitation of the second excited
state of 8Li (2.25 MeV, ). The fact that the ground and the first excited
states of 8Li were not observed is fully consistent with Shell-Model
calculations carried out for the 10Be g.\,s. and 8Li level structure applying
momentum selection rules
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