The Growth of Roots and Green Leaves of <i>Allium cepa</i>L. after the Removal of Different Parts of the Bulb

The dynamics of the growth of roots and leaves of the Allium cepa L. after the mechanical removal of a part of the root system or the bulb was studied. It was shown that, after surgical interference, the potency for organogenesis is retained, although it is weakened.

Combined Effect of Water Deficit and Salt Stress on the Structure of Mesophyll Cells in Wheat Seedlings

The purpose of the work was to assess the combined effect of drought and salinity (50, 100, 200 mМ NaCl) on the meso- and ultrastructure of mesophyll cells of wheat seedlings. Stress development was estimated by a decrease in the relative water content (RWC) and CO2-dependent O2 evolution (An) in leaves. The decrease in the RWC and in An occurred rapidly in the absence of salt in the substrate and slowly in the presence of salt, especially at a treatment of 100 mM NaCl. The resumption of watering led to the recovery of the both parameters in all variants except one with 200 mM NaCl. Structural studies showed that a weak drought stress (RWC 60%) without salinity led to the destruction of cell membranes and hyaloplasm, which did not occur in all salt treatments. By contrast, the ultrastructure of nuclei in weak drought without salinity remained unchanged, whereas in all salt treatments chromatin changed substantially. Heterochromatin underwent a strong condensation followed by the fusion into a united mass with the simultaneous loss of electron density. A strong water stress (RWC 40%) in all variants led to cell destruction and the hydrolysis of cell compounds. Under the drought without salinity, vacuoles disappeared, whereas in salt-treated samples they were retained and filled with organelles being at different degrees of degradation. Cell nuclei under strong drought stress lost their rounded shape, nuclear envelopes were destroyed, and at the end only a finely dispersed substance remained. Thus, under the combined action of drought and salt, there is some critical level of salt concentration in substrate above which the effect of NaCl changes to the adverse, which enhances the action of drought. Among structural components of mesophyll cells, the most sensitive parts to NaCl are nuclei and their chromatin.

Human photosynthesis, the ultimate answer to the long term mystery of Kleiber’s law or E = M^3/4: Implication in the context of gerontology and neurodegenerative diseases

Kleiber’s Law or E = M3/4 is a mathematical expression known since 1932 that outlines the relationship between mass (biomass) and the use of energy. It is compelling because it supports a long standing observation that larger animals appear to use energy more efficiently than smaller ones. For example, an elephant’s weight is 200,000 times of a mouse, but uses only about 10,000 fold energy;thus a cat, having a mass of about 100 times of a mouse, only spends roughly 33 fold energy. In other words, the bigger you are, the less energy per gram of tissue you actually need to stay alive. Many facts pertaining to animal size call for a rational explanation. This paper takes into account that the fascinating relationship between mass and energy use for any living thing is governed strictly by a mathematical universal formula across all living species, operating in the tiniest of bacteria to the biggest of whales and sequoia tress. For the first time, we report a capacity for the mammal eukaryotic cell to split, break or dissociate water molecules through melanin. Even though E = M3/4 was discovered eight decades ago, no proper satisfactory explanation exists. Nevertheless, our multiyear detailed study on the “Human Photosynthesis” or first found in the human retina and later in all eukaryotic cells, may finally unravel this mystery, namely, the bigger you are the more surface area you have to absorb electromagnetic radiation and the more potential exists to use that electromagnetic radiation spectra to perform work. We propose a future application of this theory in the context of human diseases, especially age-related disorders, such as retinopathy, cerebrovascular and Alzheimer disease and these implications may not only foster a better understanding of the pathobiology of these devastating diseases but also develop much more effective therapies in the foreseeable future.

Russian Collaborative Development of Reproduction Technologies for the Sustainable Management of Amphibian Biodiversity

Reproduction technologies(RTs)can provide for the reliable reproduction of amphibians,as well as perpetuation of species genetic variation with the use of biobanks.In 1982,in anticipation of the biodiversity conservation crisis,major Russian institutions collaborated in a dynamic program to develop and implement RTs for the sustainable management of amphibian biodiversity.An initial primary focus was the captive breeding of threatened Russian endemic anuran and caudate species,using RTs that varied from environmental manipulation to the use of exogenous gonadotropic hormones to stimulate reproduction.These species were mostly from Palearctic or cool mountain regions,but also included a wide range of species from warm regions.Other early achievements included the successful cryopreservation of anuran spermatozoa and anuran diploid pluripotent cell nuclei,in order to store both the matrilineal and patrilineal genomes in biobanks,with their subsequent development to the blastula stage after implantation into enucleated oocytes.After the turn of the 21st Century,in support of the priorities of the Amphibian Conservation Action Plan(2007),we developed RTs for the refrigerated storage of testicular or urinary spermatozoa for days to weeks at 4℃,the cryopreservation of urinary spermatozoa using anovel cryoprotectant,the in vitro fertilisation of hormonally induced oocytes either fresh or after refrigerated ex situ or in situ storage,and the artificial insemination of salamanders with fresh spermatozoa.In this article,we describe previously unpublished techniques and techniques from obscure Russian sources.

Comparative Molecular Mechanics and Quantum Mechanics Study of Monohydration of Nucleic Acid Bases

DNA is the most important biological molecule and its hydration contributes essentially to the structure and functions of the double helix. We analyze the monohydration of the individual bases of nucleic acids and their methyl derivatives using methods of Molecular Mechanics (MM) with the Poltev-Malenkov (PM), AMBER and OPLS force fields, as well as ab initio Quantum Mechanics (QM) calculations at MP2/6-31G(d,p) level of theory. A comparison is made between the calculated interaction energies and the experimental enthalpies of microhydration of bases, obtained from mass spectrometry at low temperatures. Each local water-base interaction energy minimum obtained with MM corresponds to the minimum obtained with QM. General qualitative agreement was observed in the geometrical characteristics of the local minima obtained via the two groups of methods. MM minima correspond to slightly more coplanar structures than those obtained via QM methods, and the absolute MM energy values overestimate corresponding values obtained with QM. For Adenine and Thymine the QM local minima energy values are closer to those obtained by the PM potential (average of 0.72 kcal/mol) than by the AMBER force field (1.86 kcal/mol). The differences in energy between MM and QM results are more pronounced for Guanine and Cytosine, especially for minima with the water molecule forming H-bonds with two proton-acceptor centers of the base. Such minima are the deepest ones obtained via MM methods while QM calculations result in the global minima corresponding to water molecule H-bonded to one acceptor and one donor site of the base. Calculations for trimethylated bases with a water molecule corroborate the MM results. The energy profiles were obtained with some degrees of freedom of the water molecule being frozen. This data will contribute to the improvement of the molecular mechanics force fields.

Possible Nature of an Electron Dense Substance in the Thylakoid Lumen of Chloroplasts

The fixation of leaves of Tanacetum vulgare L. in glutaraldehyde makes it possible to isolate chloroplasts without sacrificing an electron dense substance in the thylakoid lumen. The extraction of lipids from the chloroplasts isolated from the leaves preliminarily fixed in glutaraldehyde has demonstrated that glycerolipids (galactolipids and phospholipids) are not manifested in TLC, whereas isoprenoid lipids (chlorophyll, carotenoids) are manifested. Presumably, isoprenoid lipids are not fixed with glutaraldehyde and are extracted from the thylakoid membrane. The ultrastructural control demonstrates that the electron dense substance from the thylakoid lumen is also extracted. It is possible that this substance is of isoprenoid nature.

Ellagic acid induces apoptosis through inhibition of nuclear factor κB in pancreatic cancer cells

AIM:To determine the effect of ellagic acid on apop-tosis and proliferation in pancreatic cancer cells and to determine the mechanism of the pro-survival effects of ellagic acid. METHODS:The effect of ellagic acid on apoptosis was assessed by measuring Phosphatidylserine externalization,caspase activity,mitochondrial membrane potential and DNA fragmentation;and proliferation by measuring DNA thymidine incorporation. Mitochondrial membrane potential was measured in permeabilized cells,and in isolated mitochondria. Nuclear factor kB(NF-kB) activity was measured by electromobility shift assay(EMSA) . RESULTS:We show that ellagic acid,a polyphenolic compound in fruits and berries,at concentrations 10 to 50 mmol/L stimulates apoptosis in human pancreatic adenocarcinoma cells. Further,ellagic acid decreases proliferation by up to 20-fold at 50 mmol/L. Ellagic acid stimulates the mitochondrial pathway of apoptosis associated with mitochondrial depolarization,cytochrome C release,and the downstream caspaseactivation. Ellagic acid does not directly affect mitochondria. Ellagic acid dose-dependently decreased NF-kB binding activity. Furthermore,inhibition of NF-kB activity using IkB wild type plasmid prevented the effect of ellagic acid on apoptosis. CONCLUSION:Our data indicate that ellagic acid stimulates apoptosis through inhibition of the prosu-rvival transcription factor NF-kB.

Thymidine Glycol: The Effect on DNA Structure and DNA Binding by Site-Specific Proteins

Thymidine glycol (5,6-dihydroxy-5,6-dihydrothymidine, Tg) is a major type of oxidative damage in DNA. During chemical oligonucleotide synthesis, Tg residue was incorporated in the different positions of 17 b.p. DNA duplexes, which differ in one base pair in the internal part. According to UV-melting curves, Tg destabilizes the double helix in a sequence independent manner. In contrast, the localized alterations in duplex structure were shown by CD spectroscopy to depend on the type of base pairs flanking the Tg lesion. Molecular dynamics simulations demonstrate that Tg is partially out of the double helix. For the first time, Tg impact on several site-specific DNA-binding proteins is studied, namely p50 and p65 subunits of nuclear factor kappa-B (NF-κB) and DNA methyltransferase SsoII (M.SsoII). Our results show that p50/p50 and p65/p65 homodimers of NF-κB can tolerate a single Tg residue in the binding site quite well. Nevertheless the homodimers have different affinities to the oxidized κB site depending on the Tg position. M.SsoII can act as a transcription repressor when bound to the regulatory site. M.SsoII demonstrates decreased affinity and lowered methylation efficiency when its methylation site contains Tg in the central position. Single Tg in one half of the regulatory site decreases M.SsoII affinity to the oxidized DNA, whereas Tg presence in both half-sites prevents M.SsoII binding to such ligand.

Structural Features of Nuclei in Leaf Mesophyll Cells of Salt-Tolerant Artemisia marschalliana

All nuclei in mesophyll cells of Artemisia marschalliana are located in vacuoles and occupy up to 90% of their volume. The ultrastructural organization of chromatin in nuclei shows different degrees of its decondensation, up to complete separation of DNA from histones. It is possible that the separation of DNA from histones enables Artemisia to grow in soils with high salinity.

Structural modification of titanium surface by octacalcium phosphate via Pulsed Laser Deposition and chemical treatment

In the present study, the Pulsed Laser Deposition (PLD) technique was applied to coat titanium for orthopaedicand dental implant applications. Calcium carbonate (CC) was used as starting coating material.The deposited CC films were transformed into octacalcium phosphate (OCP) by chemical treatments. Theresults of X-ray diffraction (XRD), Raman, Fourier Transform Infrared Spectroscopy (FTIR) and scanningelectron microscopy (SEM) studies revealed that the final OCP thin films are formed on the titaniumsurface. Human myofibroblasts from peripheral vessels and the primary bone marrow mesenchymalstromal cells (BMMSs) were cultured on the investigated materials. It was shown that all the investigatedsamples had no short-term toxic effects on cells. The rate of division of myofibroblast cells growing onthe surface and saturated BMMSs concentration for the OCP coating were about two times faster than ofcells growing on the CC films.

Mossbauer and magnetization studies of magnetic phase transitions in 0.5BiFeO_(3)-0.5NaNbO_(3)and 0.5LaFeO_(3)-0.5NaNbO_(3)solid solutions

0.5AFeO_(3)-0.5NaNbO_(3)(A=Bi,La)solid solution compositions were prepared using a solid phase reaction route from high-purity starting oxides.Mossbauer studies have shown that while for 0.5BiFeO_(3)-0.5NaNbO_(3)the magnetic phase transition temperature T_(M) value is about 150 K,for 0.5LaFeO_(3)-0.5NaNbO_(3),it is only≈25 K.This dramatic difference in T_(M) values seems to be due to additional contribution of the magnetic superexchange between Fe^(3+)ions via the empty 6p-states of Bi^(3+)ions to the overall superexchange.

Biocompatibility of biphasic α,β-tricalcium phosphate ceramics in vitro

The biocompatibility of biphasicα,β-tricalcium phosphate ceramics,obtained by annealing a compact preform based onβ-tricalcium phosphate powder,was studied in vitro.It was found that within 10–30 days the adhesion of primary dental pulp stem cells located on the surface of biphasicα,β-tricalcium phosphate ceramics is suppressed.Decrease of the cell number on the surface of biphasicα,β-tricalcium phosphate ceramics,most likely,can be associated with both the pH level(acidic)as a result of hydrolysis of the more soluble phase ofα-tricalcium phosphate and with the nature of surface that changes as a result of the formation and growth of hydroxyapatite crystals.

Surface bioactivation of PEEK by neutral atom beam technology

Polyetheretherketone(PEEK)is an alternative to metallic implants and a material of choice in many applications,including orthopedic,spinal,trauma,and dental.While titanium(Ti)and Ti-alloys are widely used in many intraosseous implants due to its biocompatibility and ability to osseointegrate,negatives include stiffness which contributes to shear stress,radio-opacity,and Ti-sensitivity.Many surgeons prefer to use PEEK due to its biocompatibility,similar elasticity to bone,and radiolucency,however,due to its inert properties,it fails to fully integrate with bone.Accelerated Neutral Atom Beam(ANAB)technology has been successfully employed to demonstrate enhanced bioactivity of PEEK both in vitro and in vivo.In this study,we further characterize surfaces of PEEK modified by ANAB as well as elucidate attachment and genetic effects of dental pulp stem cells(DPSC)exposed to these surfaces.ANAB modification resulted in decreased contact angle at 72.9±4.5°as compared to 92.4±8.5°for control(p<0.01)and a decreased average surface roughness,however with a nano-textured surface profile.ANAB treatment also increased the ability of DPSC attachment and proliferation with considerable genetic differences showing earlier progression towards osteogenic differentiation.This surface modification is achieved without adding a coating or changing the chemical composition of the PEEK material.Taken together,we show that ANAB processing of PEEK surface enhances the bioactivity of implantable medical devices without an additive or a coating.

Lipid droplets: could they be involved in cancer growth and cancer-microenvironment communications?

1 INTRODUCTION Common characteristics of tumor cells include the repro-gramming of glucose and lipid metabolism,especially the upregulation of glycolysis and lipogenesis accompanied by the accumulation of lipid droplets(LDs)predominantly in aggressive cancer cells and their microenvironment,such as the cancer cells and microenvironment in Zajdela ascites hepatoma(ZAH)[1,2].This work analyzed the hypothesis that LD-rich malignant ells gain an advantage for their survival,growth,and immune escape through cancer-derived LDs acting within malignant cells and their microenvironment in a synergistic manner.