Diversity of Novel Uncultured Prokaryotes in Microbial Communities of the Yessentukskoye Underground Mineral Water Deposit

Microbiology - Caucasian Mineral Waters is a unique territory, where various types of mineral waters with overall daily flow over 16 000 m3 are concentrated in a relatively small area. The...     

Uncharged Gemini-Amphiphiles as Components of Cationic Liposomes for Delivery of Nucleic Acids

Russian Journal of Bioorganic Chemistry - New uncharged gemini-amphiphiles have been synthesized. A series of cationic liposomes based on the polycationic amphiphile...     

Role of ORL1 receptors in the regulation of cardiac resistance to arrhythmogenic effects

It has been found that intravenous administration of nociceptin (0.4 mg/kg) prevents development of aconitine-induced arrhythmias but has no effect on the incidence of occlusion, reperfusion, CaCl2-induced arrhythmias, and exacerbates epinephrine-evoked dysrhythmias. Pretreatment with hexamethonium, atropine, guanethidine and naloxone did not abolish the arrhythmic effect of nociceptin. Intracerebroventricular infusion of orphanin FQ was shown to increase cardiac tolerance of arrhythmogenic influence of aconitine, but this effect is completely abolished by hexamethonium administration. It has been suggested that stimulation of both central and peripheral ORL1 receptors increases cardiac resistance against arrhythmogenic effect of aconitine via different mechanisms.     

Three-dimensional Optical-resolution Photoacoustic Microscopy

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As the mainstays of in vivo three-dimensional (3-D) optical microscopy, single-/multi-photon fluorescence microscopy and optical coherence tomography (OCT) have demonstrated their extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been assessable. The emergence of biomedical photoacoustics has led to a new branch of optical microscopy optical-resolution photoacoustic microscopy (OR-PAM)¹, where the optical irradiation is focused to the diffraction limit to achieve cellular¹ or even subcellular² level lateral resolution. As a valuable complement to existing optical microscopy technologies, OR-PAM brings in at least two novelties. First and most importantly, OR-PAM detects optical absorption contrasts with extraordinary sensitivity (i.e., 100%). Combining OR-PAM with fluorescence microscopy³ or with optical-scattering-based OCT⁴ (or with both) provides comprehensive optical properties of biological tissues. Second, OR-PAM encodes optical absorption into acoustic waves, in contrast to the pure optical processes in fluorescence microscopy and OCT, and provides background-free detection. The acoustic detection in OR-PAM mitigates the impacts of optical scattering on signal degradation and naturally eliminates possible interferences (i.e., crosstalks) between excitation and detection, which is a common problem in fluorescence microscopy due to the overlap between the excitation and fluorescence spectra. Unique for optical absorption imaging, OR-PAM has demonstrated broad biomedical applications since its invention, including, but not limited to, neurology^{5, 6}, ophthalmology^{7, 8}, vascular biology⁹, and dermatology¹⁰. In this video, we teach the system configuration and alignment of OR-PAM as well as the experimental procedures for in vivo functional microvascular imaging.Download video file.^{(52M, mov)}     

Functional properties of photosynthetic apparatus in three <Emphasis Type="Italic">Fucus</Emphasis> species inhabiting the White Sea: Effect of dehydration

Three species of Fucus inhabiting different zones at the littoral and sublittoral of the White Sea (F. vesiculosus L., F. serratus L., and F. distichus L.) were compared with regard to performance of the photosynthetic apparatus (PSA) and PSA changes upon prolonged desiccation of algae. The content of chlorophyll a and the total content of carotenoids were significantly higher in F. serratus than in F. vesiculosus. The potential quantum yield (F _v/F _m) of photosystem II (PSII) was 0.69–0.74 in all species. The highest effective quantum yield of PSII (Y _II) was observed in F. vesiculosus plants inhabiting zones with the most intense insolation. The ratio of non-photochemical quenching to photochemical quenching (qN/qP) increased with the depth of algal habitats in the row from F. vesiculosus to F. serratus. The fluorescence parameters F. serratus deviated during desiccation from their normal values and did not recover upon the subsequent return to water. By contrast, the fluorescence parameters of F. vesiculosus and F. distichus recovered gradually after the return of algae from air to sea water. It is supposed that F. serratus plants, unlike other species, are characterized by comparatively low physiological plasticity.     

Unusual polypeptide synthesis in the kinetoplast-mitochondria from Leishmania tarentolae. Identification of individual de novo translation products.

The de novo synthesis of cytochrome c oxidase subunits I, II (COI and COII), and apocytochrome b (Cyb) was investigated in kinetoplast-mitochondria of Leishmania. The organelles were isolated after breaking whole cells with nitrogen cavitation. Individual COI, COII, and Cyb polypeptides were identified by fractionation of the kinetoplast membranes, labeled with [(35)S]methionine and cysteine, using two-dimensional (9 versus 14% and 20 versus 11%) denaturing gel electrophoresis. The reaction did not require exogenous energy sources or amino acids. On the contrary, the presence of amino acids other than methionine somewhat inhibited the labeling reaction probably by competing with the uptake of labeled amino acids. The synthesis reaction was insensitive to 100 microg/ml chloramphenicol, gentamycin, paromomycin, lincomycin, hygromycin, and tetracycline, as well as cycloheximide. The process showed a linear increase in the amount of synthesized polypeptides during the first 2 h of incubation, followed by a slower accumulation of products for up to 4 h. The de novo synthesized polypeptides were stable for several additional hours. Their assembly into respiratory complexes, investigated using two-dimensional Blue Native/N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine-SDS gels, began early during the incubation and continued throughout the course of the synthesis. This work represents the first unequivocal identification of the polypeptide synthesis in kinetoplasts.