Anaerobic Microbial Degradation of Polypropylene and Polyvinyl Chloride Samples

Microbiology - Resistance to biodegradation, which is among the most advantageous features of synthetic polymers, is also the reason for their accumulation in the environment and therefore...     

Localization of Crystallins in Muller Cells of Common Frog Retina

Cell localization of 23 kDa- and 35 kDa-crystallins in the retina of adult common frogs Rana temporaria L. was studied using indirect immunofluorescence. Intense specific fluorescence of both crystallins was observed all over the retina, in both periphery and central area. It was localized in elongated radially oriented cells, whose bodies were located in the inner nuclear layer. These cells gave many fluorescing processes in the same layer and main processes in the outer nuclear and ganglion layers, one in each. The processes formed a strong network of fibers around the photoreceptor and ganglion cells. Intense fluorescence was also observed in the layer of nerve fibers and adjoining inner limiting membrane. The distribution and morphology of crystalline-containing cells mostly coincides with what is known for the Muller cells of vertebrate eye. The identity of the cells we described and Muller cells was also confirmed using the antiserum to glial fibrillary acidic protein.     

A covalently bound photoisomerizable agonist. Comparison with reversibly bound agonists at electrophorus electroplaques

After disulphide bonds are reduced with dithiothreitol, trans-3- (α-bromomethyl)-3’-[α- (trimethylammonium)methyl]azobenzene (trans-QBr) alkylates a sulfhydryl group on receptors. The membrane conductance induced by this “tethered agonist” shares many properties with that induced by reversible agonists. Equilibrium conductance increases as the membrane potential is made more negative; the voltage sensitivity resembles that seen with 50 [mu]M carbachol. Voltage- jump relaxations follow an exponential time-course; the rate constants are about twice as large as those seen with 50 μM carbachol and have the same voltage and temperature sensitivity. With reversible agonists, the rate of channel opening increases with the frequency of agonist-receptor collisions: with tethered trans-Qbr, this rate depends only on intramolecular events. In comparison to the conductance induced by reversible agonists, the QBr-induced conductance is at least 10-fold less sensitive to competitive blockade by tubocurarine and roughly as sensitive to “open-channel blockade” bu QX-222. Light-flash experiments with tethered QBr resemble those with the reversible photoisomerizable agonist, 3,3’,bis-[α-(trimethylammonium)methyl]azobenzene (Bis-Q): the conductance is increased by cis {arrow} trans photoisomerizations and decreased by trans {arrow} cis photoisomerizations. As with Bis-Q, ligh-flash relaxations have the same rate constant as voltage-jump relaxations. Receptors with tethered trans isomer. By comparing the agonist-induced conductance with the cis/tans ratio, we conclude that each channel’s activation is determined by the configuration of a single tethered QBr molecule. The QBr-induced conductance shows slow decreases (time constant, several hundred milliseconds), which can be partially reversed by flashes. The similarities suggest that the same rate-limiting step governs the opening and closing of channels for both reversible and tethered agonists. Therefore, this step is probably not the initial encounter between agonist and receptor molecules.     

Ploidies of cardiomyocytes in human myocardial hypertrophy]

DNA cytophotometry has been performed in ventricular cardiomyocytes of hypertrophic human hearts. In the cases of hypertrophy in adults (generalized atherosclerosis, postinfarct scars), polyploidy expression did not exceed the limits of normal variability developed during childhood. In the cases of hypertrophy caused by congenital heart defects, high polyploidy has been revealed (the mean level 20c and more, where c is haploid DNA content), which considerably exceeded the upper limit of normal variability (approximately 10c). Our hypothesis has confirmed that heart hypertrophy in adults proceeds in conditions of stable genome rather than due to redundant polyploidization of the ventricular myocytes. The same idea assumes enhanced polyploidization of the myocytes in childhood in humans with congenital heart diseases.     

Neuropeptide Organization of the Nociceptive and Antinociceptive Brain Systems in the Cat

Using radioimmune techniques, we studied in detail the concentrations of -endorphin (-En), met- and leu-enkephalins (mE and lE, respectively), and substance P (SP) in a number of structures of the brainstem and forebrain of the cat. According to the proposed concept, these structures comprise the noci- and antinociceptive brain systems (NS and ANS). The above indices were measured in intact animals and in animals after nociceptive electrocutaneous stimulation (NECS) of the limb, stimulation of the ventrolateral zone of the midbrain central gray (vl SGC, a nociceptive midbrain structure), stimulation of the dorsolateral part of the above region and dorsal raphe nucleus (dl SGC and Rd, antinociceptive midbrain structures), and after combined stimulations (NECS preceded by conditioning stimulation of one of the above midbrain zones). We found that in the norm maximum SP concentrations were observed in the NS structures, while those of -En and mE were the highest in the hypothalamic nuclei belonging to the ANS and in its midbrain centers (dl SGC and Rd). Nociceptive ECS, stimulations of the studied midbrain zones, and combinations of these stimulations could result in specific and, in some cases, very significant (by an order of magnitude and more) shifts in the concentrations of the mentioned neuropeptides in the studied set of the central structures. After NECS and its combination with vl SGC stimulation, SP concentrations in the NS structures considerably increased, while -En and mE concentrations in the ANS components dropped. Stimulations of the dl SGC and Rd were accompanied by increases in the mE and -En levels and simultaneous drops in the SP concentrations in the ANS components; reciprocate shifts were observed within the NS. Changes in the lE level, which were related to the influences used, were less specific and mostly appeared as increases in this index in the structures of both the NS and ANS. Combinations of NECS with conditioning stimulations of the vl SGC, dl SGC, or Rd demonstrated that the latter exert significant modulatory effects on the NECS-induced shifts in the concentrations of the studied neuropeptides. Considering the obtained data, a hypothetical scheme of neuropeptide organization of the cerebral NS and ANS has been proposed. In the examined brain structures, there are neuronal populations belonging to the two main neurochemical systems. One of them is SP-ergic, while another consists of mE- and -En-ergic neurons; these systems are in antagonistic relations. Changes in the levels of mE and -En always induce the attended opposite shifts in the SP levels, and vice versa. The lE-ergic neuronal populations, which co-exist with the above neurochemical systems, are relatively nonspecifically activated by either (noci- and antinociceptive) drives, but, according to the pattern of its responses, the lE-ergic system is closer to the SP-ergic one. It is supposed that pain signals, when coming to the vl SGC, activate SP- and lE-ergic neuronal populations; later on, the posterior and lateral hypothalamic nuclei and preoptic region are involved in the transmission of the above signals. When released by the corresponding neuronal populations in the vl SGC, lE activates the key ANS structures (dl SGC and Rd), and the latter, in turn, activate other components of this system, which form its ascending compartment (ventromedial, dorsomedial, and paraventricular hypothalamic nuclei, septum, basolateral amygdala, hippocampal fields 3 and 4, and cingular cortex). In the ANS,-En and mE function as transmitters.     

Ligand-dependent differences in estrogen receptor beta-interacting proteins identified in lung adenocarcinoma cells corresponds to estrogenic responses

Background

A recent epidemiological study demonstrated a reduced risk of lung cancer mortality in breast cancer patients using antiestrogens. These and other data implicate a role for estrogens in lung cancer, particularly nonsmall cell lung cancer (NSCLC). Approximately 61% of human NSCLC tumors express nuclear estrogen receptor β (ERβ); however, the role of ERβ and estrogens in NSCLC is likely to be multifactorial. Here we tested the hypothesis that proteins interacting with ERβ in human lung adenocarcinoma cells that respond proliferatively to estradiol (E₂) are distinct from those in non-E₂-responsive cells.

Methods

FLAG affinity purification of FLAG-ERβ-interacting proteins was used to isolate ERβ-interacting proteins in whole cell extracts from E₂ proliferative H1793 and non-E₂-proliferative A549 lung adenocarcinoma cell lines. Following trypsin digestion, proteins were identified using liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS). Proteomic data were analyzed using Ingenuity Pathway Analysis. Select results were confirmed by coimmunoprecipitation.

Results

LC-MS/MS identified 27 non-redundant ERβ-interacting proteins. ERβ-interacting proteins included hsp70, hsp60, vimentin, histones and calmodulin. Ingenuity Pathway Analysis of the ERβ-interacting proteins revealed differences in molecular and functional networks between H1793 and A549 lung adenocarcinoma cells. Coimmunoprecipitation experiments in these and other lung adenocarcinoma cells confirmed that ERβ and EGFR interact in a gender-dependent manner and in response to E₂ or EGF. BRCA1 interacted with ERβ in A549 cell lines and in human lung adenocarcinoma tumors, but not normal lung tissue.

Conclusion

Our results identify specific differences in ERβ-interacting proteins in lung adenocarcinoma cells corresponding to ligand-dependent differences in estrogenic responses.

     

Using of 4-thiouridine and 4-thiothymidine for pyrimidine nucleoside phosphorylase studing

4-Thiouridine and 4-thiothymidine were developed as efficient substrates for spectrophotometric determination of uridine phosphorylase and thymidine phosphorylase activity. 4-Thiouridine has maximum absorbance at 330 nm (pH 7.5). The change in extinction coefficient for 4-thiouridine/4-thiouracil, deltaepsilon is 3000 M(-1) x cm(-1). It appeared that 4-thiouridine is a good substrate for uridine phosphorylase with Michaelis-Menten constant 130 microM and kcat 49 s(-1). In the case of 4-thiothymidine/4-thiothymine deltaepsilon is even larger: 5000 M(-1) x cm(-1) at 336 nm.     

Lung tissue extracellular matrix-derived hydrogels protect against radiation-induced lung injury by suppressing epithelial–mesenchymal transition

This study aimed to examine whether lung tissue extracellular matrix (ECM) hydrogels have protective effects on radiation-induced lung injury (RILI). The cytocompatibility and histocompatibility were tested for the obtained ECM-derived hydrogel. Sprague–Dawley rats were randomly divided into three groups (n = 18): control group (control); rats receiving irradiation and intratracheal injection of normal saline (IR + NS); and rats receiving irradiation and intratracheal injection of lung ECM-derived hydrogel (IR + ECM). The wet/dry weight ratio was used to evaluate the congestion and edema of the lungs. Histopathological analysis of lung tissues was performed using hemotoxylin and eosin staining and Masson's trichrome staining. Immunohistochemical staining and western blot analyses were carried out to determine the expression of epithelial–mesenchymal transition (EMT)-related proteins in lung tissues (E-cadherin, α-smooth muscle actin [α-SMA], and vimentin). In addition, tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1) and interleukin-6 (IL-6), hydroxyproline, malondialdehyde (MDA), and superoxide dismutase (SOD) levels were also evaluated. The ECM-derived hydrogels had good cytocompatibility and histocompatibility. ECM-derived hydrogel treatment improved lung histopathology injury and pulmonary edema. Higher expression of E-cadherin and lower expression of vimentin and α-SMA were found in the IR + ECM group compared with those in the IR + NS group. Hydroxyproline levels were reduced by ECM-derived hydrogel treatment compared with those in the IR + NS group. Obvious increases of TNF-α, IL-6, and TGF-β1 were identified following irradiation. Marked reductions in MDA content and increases in SOD were induced by ECM-derived hydrogel treatment in rats after radiation. ECM-derived hydrogels were shown to protect against RILI, potentially by reducing EMT, inflammation, and oxidative damage.