Halorussus halobius sp. nov., Halorussus marinus sp. nov. and Halorussus pelagicus sp. nov., isolated from salted brown alga Laminaria

Four halophilic archaeal strains, designated HD8-83T, LYG-36T, DLLS-82 and RC-68T, were isolated from the salted brown alga Laminaria of three different origins (Dalian, Lianyungang, Dalian and Rongcheng) in China. All strains had pleomorphic rod cells that were motile, lysed in distilled water, stained Gram-negative and formed red-pigmented colonies on agar plate, except DLLS-82 showing white colonies. Based on phylogenetic analyses of the 16S rRNA genes, strain HD8-83T was closely related to Halorussus litoreus HD8-51T (97.9 % similarity), strain LYG-36T and DLLS-82 were closely related to Halorussus rarus TBN4T (94.4 % and 94.7 % similarities, respectively), and strain RC-68T exhibit close to Halorussus salinus YJ-37-HT (96.9 % similarity). Phylogenetic analyses based on rpoB′ gene and 728 concatenated single-copy orthologous clusters also show these strains formed three different branches and clustered tightly with the Halorussus members. The ANI, AAI and isDDH values between strain LYG-36T and DLLS-82 were 98.9 %, 98 % and 92.4 %, showing they were different strains of same species. While those values between isolates and other Halorussus members with values below 84.7 %, 82.9 % and 28.9 %. Based on the phenotypic, chemotaxonomic and phylogenetic properties, the strains HD8-83T, LYG-36T, DLLS-82 and RC-68T represent three novel species of the genus Halorussus for which the names Halorussus halobius sp. nov. (type strain HD8-83T = CGMCC 1.15334T = JCM 31110T), Halorussus marinus sp. nov. (type strain LYG-36T = CGMCC 1.13606T = JCM 32952T, reference strain DLLS-82 = CGMCC 1.13604 = JCM 32951) and Halorussus pelagicus sp. nov. (type strain RC-68T = CGMCC 1.13609T = JCM 32953T) are proposed.

SPECTRUM OF OWN FREQUENCIES OF A SPATIAL SURFACING GIRDER

Statement of the problem. The scheme of a statically definable girder of a spatial rectangular surfacing is discussed. The problem is to identify the formula for the dependence of the lower estimate of the first frequency of the natural oscillations of the structure by means of the Donkerley method on the number of panels. The truss has supports on the sides and consists of separate rod cells connected in pyramids. Results. Based on the analysis of the sequence of analytical solutions for the first frequency of girders with a different number of panels by induction, the coefficients in the desired formula are derived. The common members of the sequences of coefficients are found as solutions of homogeneous recurrent equations formed according to the results of the calculations using Maple operators. The resulting dependences are obtained in the form of polynomials by the number of panels. A comparison of the analytical solution with the numerical one is provided.Conclusions. An algorithm for deriving an analytical estimate of the fundamental frequency of oscillations of a spatial structure depending on the number of panels, mass, size, and elastic properties of the material is shown. The spectrum of oscillation frequencies of the structure is analyzed. The resulting dependences can be employed in seismic and structural optimization problems.

Gypenosides Alleviate Cone Cell Death in a Zebrafish Model of Retinitis Pigmentosa

Retinitis pigmentosa (RP) is a group of visual disorders caused by mutations in over 70 genes. RP is characterized by initial degeneration of rod cells and late cone cell death, regardless of genetic abnormality. Rod cells are the main consumers of oxygen in the retina, and after the death of rod cells, the cone cells have to endure high levels of oxygen, which in turn leads to oxidative damage and cone degeneration. Gypenosides (Gyp) are major dammarane-type saponins of Gynostemma pentaphyllum that are known to reduce oxidative stress and inflammation. In this project we assessed the protective effect of Gyp against cone cell death in the rpgrip1 mutant zebrafish, which recapitulate the classical pathological features found in RP patients. Rpgrip1 mutant zebrafish were treated with Gyp (50 µg/g body weight) from two-months post fertilization (mpf) until 6 mpf. Gyp treatment resulted in a significant decrease in cone cell death compared to that of untreated mutant zebrafish. A markedly low level of reactive oxygen species and increased expression of antioxidant genes were detected in Gyp-incubated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Similarly, the activities of catalase and superoxide dismutase and the level of glutathione were significantly increased in Gyp-treated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Gyp treatment also decreased endoplasmic reticulum stress in rpgrip1 mutant eyes. Expression of proinflammatory cytokines was also significantly decreased in Gyp-treated mutant zebrafish eyes compared to that of untreated mutant zebrafish. Network pharmacology analysis demonstrated that the promotion of cone cell survival by Gyp is possibly mediated by multiple hub genes and associated signalling pathways. These data suggest treatment with Gyp will benefit RP patients.

Spectrum of Own Frequencies of a Spatial Surfacing Grid

Постановка задачи. Рассматривается схема статически определимой фермы пространственного прямоугольного покрытия. Ставится задача найти формулу зависимости нижней оценки первой частоты собственных колебаний конструкции по методу Донкерлея от числа панелей. Ферма имеет опоры по сторонам и состоит из отдельных стержневых ячеек, соединенных в пирамиды. Результаты. Из анализа последовательности аналитических решений для первой частоты ферм с различным числом панелей методом индукции выводятся коэффициенты в искомой формуле. Общие члены последовательностей коэффициентов находятся как решения однородных рекуррентных уравнений, образованных по результатам расчетов с помощью операторов Maple . Найденные зависимости получены в виде полиномов по числу панелей. Дано сравнение аналитического решения с численным. Выводы. Приведен алгоритм вывода аналитической оценки основной частоты колебаний пространственной конструкции в зависимости от числа панелей, массы, размеров и упругих свойств материала. Проанализирован спектр частот колебаний сооружения. Найденные зависимости могут быть использованы в задачах сейсмостойкости и оптимизации конструкции. Statement of the problem. The scheme of a statically definable truss of a spatial rectangular covering is discussed. The problem is to identify the formula for the dependence of the lower estimate of the first frequency of the natural oscillations of the structure by means of the Donkerley method on the number of panels. The truss has supports on the sides and consists of separate rod cells connected in pyramids. Results. Based on the analysis of the sequence of analytical solutions for the first frequency of trusses with a different number of panels by induction, the coefficients in the desired formula are derived. The common members of the sequences of coefficients are found as solutions of homogeneous recurrent equations formed according to the results of the calculations using Maple operators. The resulting dependences are obtained in the form of polynomials by the number of panels. A comparison of the analytical solution with the numerical one is provided. Conclusions. An algorithm for deriving an analytical estimate of the fundamental frequency of oscillations of a spatial structure depending on the number of panels, mass, size, and elastic properties of the material is shown. The spectrum of oscillation frequencies of the structure is analyzed. The resulting dependences can be employed in seismic and structural optimization problems.

Development of Retinal Degenerative Model Using Lead Acetate (PbAc) in Zebrafish: Morphological and Behavioral Aspects

Lead intoxication reduces cGMP phosphodiesterase activity and enhances the influx of Ca2+ in photoreceptor cells that trigger ATP loss. Thus, releasing proapoptotic factors and activating caspase cascade results in retinal cell apoptosis. In the current study, lead acetate (PbAc) induced retinal degenerative model which mimics ocular degenerative disorders like macular degeneration and retinitis pigmentosa. Qualitative and quantitative analysis of retinal histology, with dose and time response parameters, showed 0.08mg/L concentration for 15 days of treatment was the appropriate dose to develop the retinal degeneration model. Its intoxication affected the photoreceptor cells thus contributing to above mentioned disorders. At an ultrastructural level, it was observed that PbAc induce retinal degeneration by damaging outer and inner segments of the photoreceptors especially the rod cells. Escape response behavior also showed a significant decrease in visual response to changing contrasts. Thus, PbAc was inducing degeneration of retina between pigmented epithelium and photoreceptor layer for further retinal regenerative studies. Lead intoxication reduces cGMP phosphodiesterase activity and enhances the influx of Ca2+ in photoreceptor cells that trigger ATP loss. Thus, releasing proapoptotic factors and activating caspase cascade results in retinal cell apoptosis. In the current study, lead acetate (PbAc) induced retinal degenerative model which mimics ocular degenerative disorders like macular degeneration and retinitis pigmentosa. Qualitative and quantitative analysis of retinal histology, with dose and time response parameters, showed 0.08mg/L concentration for 15 days of treatment was the appropriate dose to develop the retinal degeneration model. Its intoxication affected the photoreceptor cells thus contributing to above mentioned disorders. At an ultrastructural level, it was observed that PbAc induce retinal degeneration by damaging outer and inner segments of the photoreceptors especially the rod cells. Escape response behavior also showed a significant decrease in visual response to changing contrasts. Thus, PbAc was inducing degeneration of retina between pigmented epithelium and photoreceptor layer for further retinal regenerative studies.

Olfactory Rod Cells: A Rare Cell Type in the Larval Zebrafish Olfactory Epithelium With a Large Actin-Rich Apical Projection

We report the presence of a rare cell type, the olfactory rod cell, in the developing zebrafish olfactory epithelium. These cells each bear a single actin-rich rod-like apical projection extending 5–10 μm from the epithelial surface. Live imaging with a ubiquitous Lifeact-RFP label indicates that the olfactory rods can oscillate. Olfactory rods arise within a few hours of the olfactory pit opening, increase in numbers and size during larval stages, and can develop in the absence of olfactory cilia. Olfactory rod cells differ in morphology from the known classes of olfactory sensory neuron, but express reporters driven by neuronal promoters. A sub-population of olfactory rod cells expresses a Lifeact-mRFPruby transgene driven by thesox10promoter. Mosaic expression of this transgene reveals that olfactory rod cells have rounded cell bodies located apically in the olfactory epithelium and have no detectable axon. We offer speculation on the possible function of these cells in the Discussion.

The heterochromatin block that functions as a rod cell microlens in owl monkeys formed within a 15 million year time span

In rod cells of many nocturnal mammals, heterochromatin localizes to the central region of the nucleus and serves as a lens to send light efficiently to the photoreceptor region. The genus Aotus (owl monkeys) is commonly considered to have undergone a shift from diurnal to nocturnal lifestyle. We recently demonstrated that rod cells of the Aotus species A. azarae possess a heterochromatin block at the center of its nucleus. The purpose of the present study was to estimate the time span in which the formation of the heterochromatin block took place. We performed three-dimensional hybridization analysis of the rod cell of another species, A. lemurinus. This analysis revealed the presence of a heterochromatin block that consisted of the same DNA components as those in A. azarae. These results indicate that the formation was complete at or before the separation of the two species. Based on the commonly accepted evolutionary history of New World monkeys and specifically of owl monkeys, the time span for the entire formation process was estimated to be 15 million years at most.

Heterochromatin flexibility contributes to chromosome segregation in the cell nucleus

While there is a prevalent genome organization in eukaryotic cells, with heterochromatin concentrated at the nuclear periphery, anomalous cases do occur. Deviations of chromatin distribution are frequent, for example, upon aging, under malignant diseases, or even naturally in rod cells of nocturnal mammals. Using molecular dynamic simulations, we study the segregation of heterochromatin in the cell nucleus by modeling interphase chromosomes as diblock ring copolymers confined in a rigid spherical shell. In our model, heterochromatin and euchromatin are distinguished by their bending stiffnesses, while an interaction potential between the spherical shell and chromatin is used as a proxy for lamin-associated proteins. Our simulations indicate that in the absence of attractive interactions between the nuclear shell and the chromatin, the majority of heterochromatin segregates towards the nuclear interior due to depletion of less flexible heterochromatin segments from the nuclear periphery. This inverted chromatin distribution is in accord with experimental observations in rod cells. This “inversion” is also found to be independent of the heterochromatin concentration and chromosome number, and is further enhanced by additional attractive interactions between heterochromatin segments. as well as by allowing bond-crossing to emulate topoisomerase activity. The usual chromatin distribution, with heterochromatin at the periphery, can be recovered by further increasing the bending stiffness of heterochromatin segments or by turning on attractive interactions between the nuclear shell and heterochromatin. Overall, our results indicate that bending stiffness of chromatin could be a contributor to chromosome organization along with differential effects of HP1α-driven phase segregation and of loop extruders, and interactions with the nuclear envelope and topological constraints.

Visual adaptation of opsin genes to the aquatic environment in sea snakes

Background Evolutionary transitions from terrestrial to aquatic life history cause drastic changes in sensory systems. Indeed, the drastic changes in vision have been reported in many aquatic amniotes, convergently. Recently, the opsin genes of the full-aquatic sea snakes have been reported. However, those of the amphibious sea snakes have not been examined in detail. Results Here, we investigated opsin genes and visual pigments of sea snakes. We determined the sequences of SWS1, LWS, and RH1 genes from one terrestrial, three amphibious and four fully-aquatic elapids. Amino acid replacements at four and one spectra-tuning positions were found in LWS and RH1, respectively. We measured or predicted absorption of LWS and RH1 pigments with A1-derived retinal. During their evolution, blue shifts of LWS pigments have occurred stepwise in amphibious sea snakes and convergently in both amphibious and fully-aquatic species. Conclusions Blue shifted LWS pigments may have adapted to deep water or open water environments dominated by blue light. The evolution of opsins differs between marine mammals (cetaceans and pinnipeds) and sea snakes in two fundamental ways: (1) pseudogenization of opsins in marine mammals; and (2) large blue shifts of LWS pigments in sea snakes. It may be possible to explain these two differences at the level of photoreceptor cell composition given that cone and rod cells both exist in mammals whereas only cone cells exist in fully-aquatic sea snakes. We hypothesize that the differences in photoreceptor cell compositions may have differentially affected the evolution of opsins in divergent amniote lineages.

Inhibition of VCP preserves retinal structure and function in autosomal dominant retinal degeneration

ABSTRACTDue to continuously high production rates of rhodopsin (RHO) and high metabolic activity, photoreceptor neurons are especially vulnerable to defects in proteostasis. A proline to histidine substitution at position 23 (P23H) leads to production of structurally misfolded RHO, causing the most common form of autosomal dominant Retinitis Pigmentosa (adRP) in North America. The AAA-ATPase valosin-containing protein (VCP) extracts misfolded proteins from the ER membrane for cytosolic degradation. Here, we provide the first evidence that inhibition of VCP activity rescues degenerating P23H rod cells and improves their functional properties in P23H transgenic rat and P23H knock-in mouse retinae, both in vitro and in vivo. This improvement correlates with the restoration of the physiological RHO localization to rod outer segments (OS) and properly-assembled OS disks. As a single intravitreal injection suffices to deliver a long-lasting benefit in vivo, we suggest VCP inhibition as a potential therapeutic strategy for adRP patients carrying mutations in the RHO gene.