The Content of Vitamin C in the Grape Grown under the Conditions of Southwestern Siberia

Russian Journal of Bioorganic Chemistry - The grape is a highly valuable food stuff owing to the presence of a number of biologically active substances, and vitamins occupy a special place among...     

Results of testing the comparatory method: The curvature of the shell valve frontal section is inappropriate as a systematic character for the freshwater pearl mussel of the genus Margaritifera

This paper continues a discussion on the number of pearl mussel species of the genus Margaritifera in northern Europe. A biometric study of 1711 pearl mussel Margaritifera margaritifera shells from 15 rivers in Russia and Latvia (basins of the White and Baltic seas) has been conducted. All the examined samples fall into two groups: the northern group (with the shells more flattened on average, f. margaritifera) and the southern one (with more convex shells, f. elongata); the boundary between these groups is at 63° N. Analysis of intrapopulation variation has shown that the samples contain individuals that correspond to f. margaritifera, f. elongata, and f. borealis. However, any hiatus between these forms is absent in all the samples, and individuals belonging to two intermediate forms are rather frequent. The hypothesis on the species specificity of the shell valve frontal section has not been confirmed based on examination of large shell samples. The pearl mussels inhabiting rivers of Northern Europe belong to a single species, M. margaritifera.     

Interactive effects of elevated temperature and CO2 levels on metabolism and oxidative stress in two common marine bivalves (Crassostrea virginica and Mercenaria mercenaria)

Marine bivalves such as the hard shell clams Mercenaria mercenaria and eastern oysters Crassostrea virginica are affected by multiple stressors, including fluctuations in temperature and CO₂ levels in estuaries, and these stresses are expected to be exacerbated by ongoing global climate change. Hypercapnia (elevated CO₂ levels) and temperature stress can affect survival, growth and development of marine bivalves, but the cellular mechanisms of these effects are not yet fully understood. In this study, we investigated whether oxidative stress is implicated in cellular responses to elevated temperature and CO₂ levels in marine bivalves. We measured the whole-organism standard metabolic rate (SMR), total antioxidant capacity (TAOC), and levels of oxidative stress biomarkers in the muscle tissues of clams and oysters exposed to different temperatures (22 and 27 °C) and CO₂ levels (the present day conditions of ~ 400 ppm CO₂ and 800 ppm CO₂ predicted by a consensus business-as-usual IPCC emission scenario for the year 2100). SMR was significantly higher and the antioxidant capacity was lower in oysters than in clams. Aerobic metabolism was largely temperature-independent in these two species in the studied temperature range (22–27 °C). However, the combined exposure to elevated temperature and hypercapnia led to elevated SMR in clams indicating elevated costs of basal maintenance. No persistent oxidative stress signal (measured by the levels of protein carbonyls, and protein conjugates with malondialdehyde and 4-hydroxynonenal) was observed during the long-term exposure to moderate warming (+ 5 °C) and hypercapnia (~ 800 ppm CO₂). This indicates that long-term exposure to moderately elevated CO₂ and temperature minimally affects the cellular redox status in these bivalve species and that the earlier observed negative physiological effects of elevated CO₂ and temperature must be explained by other cellular mechanisms.     

Metabolic effects of ganglioside GM1 on PC12 cells in oxidative stress depend on modulation of activity of tyrosine kinase Trk of receptors

There have been obtained evidences that not only GM1, but also other main brain gangliosides (GD1a, GD1b, and GT1b) increase viability of cells of the neuronal line PC12 under action of H₂O₂. By the example of GM1 and GD1a, gangliosides have been shown to produce a protective effect on PC12 cells under conditions of oxidative stress both at micro- and nanomolar concentrations that are physiological concentrations of gangliosides in cerebrospinal fluid. For the first time, GM1 at nanomolar concentrations was shown to decrease the H₂O₂-induced formation of reactive oxygen species (ROS). It was found that in the presence of inhibitor of tyrosine kinase Trk of receptors K-252a, GM1 at concentrations of 10 μM and 10 nM lost its ability to produce such metabolic effects as a decrease of ROS accumulation and of the degree of oxidative inactivation of Na⁺,K⁺-ATPase in PC12 cells, as well as ceased to increase viability of these cells under conditions of oxidative stress. The dependence of protective and metabolic effects of gangliosides GM1 in PC12 cells treated with H₂O₂ on modulation of activity of activity of tyrosine kinase Trk receptors (i.e., from the same signal system) agrees with concept about the essential role of oxidant effect of GM1 in its increase of cell viability.     

Intensive protein synthesis in neurons and phosphorylation of beta-amyloid precursor protein and tau-protein are triggering factors of neuronal amyloidosis and Alzheimer’s disease

Studies of Alzheimer’s disease have become particularly important and attract now much attention of scientists all over the world due to worldwide dissemination of this dangerous disorder. Causes of this pathology still remain unknown, while the final image, originally obtained on microscopic brain sections from patients with this disease more than a hundred years ago, is well familiar to clinicians. This includes deposition of amyloid-β (Aβ) in the brain tissue of senile plaques and fibrils. Many authors believe that the deposition of Aβ provokes secondary neuronal changes, responsible for death of neurons. Other authors associate the death of neurons with hyperphosphorylation of tau-proteins, which form neurofibrillar tangles inside nerve cells and cause their death. Creation of methods of preclinical diagnostics and effective treatment of Alzheimer’s disease requires novel knowledge: on the nature of triggering factors of sporadic forms of Alzheimer’s disease, on cause-effect relationships of phosphorylation of amyloid precursor protein with formation of pathogenic beta-amyloids, on the relationship between these factors underlying tau-protein hyperphosphorylation and neuron death. In this review we have analyzed reports describing increased intensity of protein synthesis in neurons under normal and various stress conditions, possibility of development of energy imbalance of neurons and activation of their protective systems. Phosphorylation and hyperphosphorylation of tau-proteins is also tightly associated with protective mechanisms of cells and with processes of evacuation of phosphates, adenosine monophosphates and pyrophosphates from the region of protein synthesis. Prolonged highly intensive protein synthesis causes overload of protective mechanisms and impairments in concerted metabolic processes. This leads to neuronal dysfunction, transport collapse, and death of neurons.     

Ortho-phthalic acid esters in lipophilic extract from the cell culture of <Emphasis Type="Italic">Aconitum baicalense</Emphasis> Turcz ex Rapaics 1907

Optically active bis-2R(–)ethylhexyl o-phthalate was obtained with 0.18% yield from dry cultured cells of Aconitum baicalense Turcz ex Rapaics 1907 by extraction with petroleum ether followed by silica gel column chromatography. Its structure was confirmed by the analysis of ¹³C and ¹H NMR spectra. Seasonal fluctuations of quantitative phthalate content in A. baicalense cells were identified. The tests were performed under conditions excluding the presence of phthalates in reagents, materials, and laboratory dishes. The same substance was shown to be produced by cultivated cells of other plants. Biosynthesis of esters of ortho-phthalic acid by cultivated plant cells was discovered for the first time.     

Hydrocarbon biodegradation and surfactant production by acidophilic mycobacteria

Production of biosurfactants by acidophilic mycobacteria was demonstrated in the course of aerobic degradation of hydrocarbons (n-tridecane, n-tricosane, n-hexacosane, model mixtures of С₁₄–С₁₇, С₁₂?С₁₉, and С₉–С₂₁n-alkanes, 2,2,4,4,6,8,8-heptamethylnonane, squalane, and butylcyclohexane) and their complex mixtures (hydrocarbon gas condensate, kerosene, black oil, and paraffin oil) under extremely acidic conditions (pH 2.5). When grown on hydrocarbons, the studied bacterial culture AG_S10 caused a decrease in the surface and interfacial tension of the solutions (to the lowest observed values of 26.0 and 1.3 mN/m, respectively) compared to the bacteria-free control. The rheological characteristics of the culture changed only when mycobacteria were grown on hydrocarbons. Neither the medium nor the cell-free culture liquid had the surfactant activity, which indicated formation of an endotype biosurfactant by mycobacteria. Biodegradation of n-alkanes was accompanied by an increase in cell numbers, surfactant production, and changes in the hydrophobicity of bacterial cell surface and in associated phenomena of adsorption and desorption to the hydrocarbon phase. Research on AGS10 culture liquids containing the raw biosurfactant demonstrated the preservation of its activity within a broad range of pH, temperature, and salinity.     

Effect of partial hepatectomy on the invertor mechanism of regulation of the Na+,K+-ATPase activity in hepatocytes of rats of various ages]

Age peculiarities of partial hepatectomy effect on the hepatocytes plasma membrane Na+, K(+)-ATPase activity and its insulin-induced stimulation has been studied. It has been shown that partial hepatectomy does not change basal Na+, K(+)-ATPase activity in adult rats. In old partial hepatectomised rats Na+, K(+)-ATPase activity is slightly higher than in control old rats, although this increase is not statistically significant. At the same time, partial hepatectomy acts differently on the insulin-induced Na+, K(+)-ATPase activation in adult and old rats. Insulin activates Na+, K(+)-ATPase at the same extent both in control and partial hepatectomized adult animals. In old hepatectomized rats, but not in old control animals, insulin stimulates Na+, K(+)-ATPase activity as well as. Thus hepatectomy "rejuvenates" old hepatocytes and results in recovery of invertor mechanism of Na+, K(+)-ATPase activation.     

Obtaining mice that carry human mitochondrial DNA transmitted to the progeny

To study human diseases associated with mutations in mitochondrial DNA one needs an animal model in which the distribution of abnormal mtDNA and its impact on the phenotype might be followed. We isolated human mitochondria from HepG2 cell culture and microinjected them into murine zygotes, upon which those were transplanted to the pseudopregnant mice. PCR with species-specific primers allowed detecting human mtDNA in the tissues of 7-13-day embryos. No serious alterations in the development of transmitochondrial embryos were noticed. Among various organs/tissues of the 13-day embryos, human mtDNA was detected only in the heart, skeletal muscles, and stomach, which is in line with its uneven distribution among the blastomeres of an early mouse embryo that we described previously. In four recipient females, the microinjected zygotes were allowed to develop to term, the four neonate males of their joint litter were sacrificed, and in three of them human mtDNA was detected in the heart, skeletal muscles, stomach, brain, testes, and bladder. Six females of that joint litter were grown and mated to intact males. In the progeny (F1) of one of the females two mice were carrying human mtDNA in the heart, skeletal muscles, stomach, brain, lungs, uterus, ovaries, and kidneys. The study confirms the possibility to obtain transmitochondrial mice carrying human mtDNA that is transmitted to the animals of the next generation. Our results also indicate that among the organs to which human mtDNA is distributed some are more likely to receive it than others.     

Synthesis and Secretion of Proteinases by Bacillus intermedius in the Late Stages of Sporulation

In the late stages of sporulation, cells of Bacillus intermedius 3-19 secreted into the medium two proteinases, glutamyl endopeptidase and subtilisin, whose maximum activities were recorded in the 40th and 44th hours of growth, respectively. By estimating -galactosidase activity as a marker of cytoplasmic membrane integrity, it was revealed that the accumulation of these proteinases in the medium was a result of their secretion and not of lysis of the cell envelope. Concentrations of peptone and inorganic phosphate ensuring the maximum production of the enzymes were established. Ammonium ions were shown to inhibit the production of proteinases by the mechanism of repression by nitrogen metabolites.