It is well known that X-ray crystallography is based on X-ray diffraction (XRD) for atoms and molecules. The diffraction pattern arises as a result of scattering of incident radiation, which makes it ...possible to determine the structure of the scattering substance. With the advent of ultrashort radiation sources, the theory and interpretation of X-ray diffraction analysis have remained the same. This work shows that when an attosecond laser pulse is scattered on a DNA molecule, including during its nicking and bending, the pulse duration is an important characteristic of the scattering. In this case, the diffraction pattern changes significantly compared to the previously known scattering theory. The results obtained must be used in XRD theory to study DNA structures, their mutations and damage, since the previously known theory can produce large errors and, therefore, the DNA structure can be “decoding” incorrectly.
Currently, X-ray diffraction analysis (XRD) with high spatial and time resolution (TR-XRD) is based on the known theory of X-ray scattering, where the main parameter of USP-its duration-is not taken ...into account. In the present work, it is shown that, for scattering of attosecond USPs on DNA and RNA trinucleotides, the pulse length is the most important scattering parameter. The diffraction pattern changes considerably in comparison with the previously known scattering theory. The obtained results are extremely important in TR-XRD when using attosecond pulses to study trinucleotides of DNA and RNA, because with the previously known scattering theory, which does not take into account the duration of USP, one cannot correctly interpret, and therefore "decode", DNA and RNA structures.
The scattering of X-ray ultrashort pulses (USPs) is an important aspect of the diffraction analysis of matter using modern USP sources. The theoretical basis, which considers the specifics of the ...interaction of ultrashort pulses with complex polyatomic structures, is currently not well developed. In general, research is focused on the specifics of the interaction of ultrashort pulses with simple systems-these are atoms and simple molecules. In this work, a theory of scattering of X-ray ultrashort pulses by complex polyatomic structures is developed, considering the specifics of the interaction of ultrashort pulses with such a substance. The obtained expressions have a rather simple analytical form, which allows them to be used in diffraction analysis. As an example, it is shown that the obtained expressions can be used to study the structures of deoxyribonucleic (DNA) and ribonucleic (RNA) acids.
•Human fetal brain material was studied between the 8th gestational week and birth.•NeuN-, SYP-, NSE-, TH-, GFAP-, MBP- assays were used to record neuronal and glial development of the prepiriform ...cortex.•Four periods of the prepiriform cortex foetal development are suggested.•The prepiriform cortex approaches a state of maturation similar to that at birth on the 30th gestational week.•The prepiriform cortex is characterized by earlier developmental rates and matures prior to other pallial regions.
The prepiriform cortex is a part of the phylogenetically oldest pallial division (paleocortex) representing the primary olfactory cortex. While olfactory centers in laboratory animals have been extensively investigated, the developmental timetable of the human prepiriform area is poorly understood. Thus, in the present study we aim to examine the prepiriform cortex in human fetuses from eight postconceptional weeks to birth. Based on cytoarchitecture and immunohistochemistry analysis (NeuN-, SYP-, NSE-, TH-, GFAP-, MBP-) four main periods of the prepiriform cortex fetal development are suggested: the beginning of prefetal stage (the eighth week from conception), the period from the ending of prefetal stage (9–12 postconceptional weeks) to 17 weeks of gestation, 18–27 weeks of gestation and the late fetal period (29–40 gestational weeks). We found that the initial layer differentiation took place before the ninthtenth weeks from conception and by ten weeks the paleocortical plate of the prepiriform cortex was shaped. Both total cell density and NeuN-immunoreactive cell density peaked in the early fetuses and started to decrease after 17 gestational weeks, attaining intermediate values at 18–27 weeks and becoming significantly lower in the late fetuses. In contrast, the NeuN-immunoreactive cell ratio gradually increased over the whole examined period. The prepiriform cortex was defined as approaches the state at birth at 30 gestational weeks. The same developmental periods were observed with SYP- and NSE-assays. No significant distribution of TH immunoreactivity was described in the prepiriform cortex of human fetuses. The prior paleocortex development was demonstrated using glial markers: GFAPimmunoreactivity appeared in the prepiriform cortex at the middle of the early fetal period, ahead of the neocortex and insular cortex. The earlier rates of GFAP-immunoreactivity expansion in the prepiriform cortex, as compared to other pallial regions, persisted in the later fetuses. The first MBP-immunoreactive fibres within pallium were detected in the lateral olfactory tract at 30 weeks. Therefore, the prepiriform cortex approaches a level of maturation similar to that at birth already at the beginning of the late fetal period and matures prior to other pallial regions.
The exposure of electrospray droplets to vapors of reagents of various base strengths affects protein negative charge state distributions independent of initial solution conditions. Volatile bases ...are introduced into the counter-current nitrogen drying gas of an electrospray interface to interact with charged droplets as they undergo desolvation/disintegration, shifting charge state distributions of proteins to higher, more negative, charge states. Alterations of charge state distributions can implicate protein folding/unfolding phenomena. Species bound by relatively weak interactions can be preserved, at least to some extent, allowing for the observation of high charge states of protein−ligand complexes, such as high negative charge states of holomyoglobin. The binding of carbonic anhydrase with its Zn2+ cofactor is apparently preserved when the holo-form of the protein is exposed to basic vapors (i.e., the Zn2+ ion remains associated with the protein), but this prevents the appearance of charge states higher than −17. Charge state distributions of proteins containing disulfide bonds shift slightly with the leak-in of basic vapors, but when these disulfide bonds are reduced with dithiothreitol in solution, charge states higher than the number of acidic sites (Asp, Glu, and C-terminus) are observed. Since there is no observed change in the distributions of buffered proteins exposed to these reagent vapors, the charge state changes are attributed largely to a pH affect. High pK a and highly volatile reagents have been found to be the most effective in terms of observing the maximum negative charge state of the biomolecule of interest.
Reptiles in Space Missions: Results and Perspectives Gulimova, Victoria; Proshchina, Alexandra; Kharlamova, Anastasia ...
International journal of molecular sciences,
06/2019, Volume:
20, Issue:
12
Journal Article
Peer reviewed
Open access
Reptiles are a rare model object for space research. However, some reptile species demonstrate effective adaptation to spaceflight conditions. The main scope of this review is a comparative analysis ...of reptile experimental exposure in weightlessness, demonstrating the advantages and shortcomings of this model. The description of the known reptile experiments using turtles and geckos in the space and parabolic flight experiments is provided. Behavior, skeletal bones (morphology, histology, and X-ray microtomography), internal organs, and the nervous system (morphology, histology, and immunohistochemistry) are studied in the spaceflight experiments to date, while molecular and physiological results are restricted. Therefore, the results are discussed in the scope of molecular data collected from mammalian (mainly rodents) specimens and cell cultures in the parabolic and orbital flights and simulated microgravity. The published data are compared with the results of the gecko model studies after the 12-44.5-day spaceflights with special reference to the unique peculiarities of the gecko model for the orbital experiments. The complex study of thick-toed geckos after three spaceflights, in which all geckos survived and demonstrated effective adaptation to spaceflight conditions, was performed. However, future investigations are needed to study molecular mechanisms of gecko adaptation in space.
•Changes in Purkinje cells were detected in the vestibular cerebellum after a space flight.•These changes were nonspecific and reversible.•Thick-toed geckos are a useful model for space flight ...studies of the vertebrate cerebellum.
The aim of this study was to estimate the effects of long-term space flights on neuronal and glial cells of the vestibular cerebellum of C57/BL6N mice and thick-toed geckos (Chondrodactylus turnery GRAY, 1864). The cerebella from 26 mice and 13 geckos were used in this study. Ten mice and five geckos were flown aboard the BION-M1 biosatellite. The other animals were used as controls. We used immunohistochemical techniques and classical histological method to reveal cell types in the vestibular cerebellum. Nonspecific pathomorphological changes in the Purkinje cells (such as chromatolysis, vacuolization and hyperchromatosis) were observed in the flight groups. However, these changes are reversible and were also found in some neurons in the control groups. In addition, as the vestibular cerebellum is an evolutionarily stable structure, thick-toed geckos may be a useful model for space flight studies on the vertebrate cerebellum.
Usually in quantum optics, the theory of large- and small-scale waveguide beam splitters is the same. In this paper, it is shown that the theory of the nanoscale waveguide beamsplitter has a ...significant difference from a similar device, but of a larger scale. It is shown that the previously known theory of the waveguide beam splitter is a particular case of the theory presented here. The wave function at the output ports of the nanoscale beam splitter is analyzed. The results obtained are sensitive to the size of the beam splitter, the coupling parameter of the two waveguides, and the degree of nonmonochromaticity of the photons entering the first and second ports of the beam splitter. The results are important for quantum technologies using a nanosized beam splitter.
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