Pleiotropic effects of chitinase gene from Serratia plymuthica in transgenic potato

We estimate the influence of transgenic bacterial chitinase from soilborne Serratia plymuthica onto agronomical important traits of potato, such as productivity and non-specific resistance. Transgene has been delivered into potato variety Delfin via Agrobacterial transformation with pGreen0229 and pBI121-based vectors. Growth inhibition of chitin-containing pathogenic fungi was shown. However, over 40% oftransgenic lines demonstrated decreased non-specific resistance to late blight (down to 62% compared to control genotype), as well as 40-60% productivity drop.     

Leptinotarsa decemlineata Say sensitivity to ionizing radiation and pesticides

The effects of acute gamma-irradiation on the Colorado potato beetle (Leptinotarsa decemlineata Say) and sensitivity of insects, long time exposed on radioactively contaminated territories, to pesticides were studied. LD50 values of insects to ionizing radiation during the ontogenesis process was shown to increase (from 8 to 48 Gy). Differences were noted in the development rates of the natural population of beetles collected on agricultural lands with 137Cs contamination density of 0.05-1.2 MBq/m2, with the sensitivity to various pesticide groups being the same.     

Taphonomy and compositional fidelity of Quaternary fossil assemblages of terrestrial gastropods from carbonate-rich environments of the Canary Islands

Quaternary aeolian deposits of the Canary Islands contain well‐preserved terrestrial gastropods, providing a suitable setting for assessing the taphonomy and compositional fidelity of their fossil record over ~13 kyr. Nine beds (12, 513 shells) have been analysed in terms of multivariate taphonomic and palaeoecological variables, taxonomic composition, and the stratigraphic and palaeontological context. Shells are affected by carbonate coatings, colour loss and fragmentation. Shell preservation is size‐specific: juveniles are less fragmented and show colour preservation more commonly than adults. In palaeosols, the adult shell density correlates negatively with the proportion of fragmented adults, negatively with the proportion of juveniles, and positively with the proportion of adults with coatings. High bioturbation intensity in palaeosols is associated with low shell fragmentation and high proportion of shells with coatings. These relationships imply that high adult density in palaeosols was driven by an increase in shell production rate (related to a decrease in predation rates on adults and a decrease in juvenile mortality) and a decrease in shell destruction rate (related to an increase in durability enhanced by carbonate precipitation). In dunes, the relationships between taphonomic alteration, shell density and bioturbation are insignificant. However, dune assemblages are characterized by a lower frequency of shells with coatings and higher rates of colour loss, indicating lower shell durability in dunes than in palaeosols. Additionally, non‐random differences in the coating proportion among palaeosols imply substantial temporal variation in the rate of carbonate crust formation, reflecting long‐term changes in bioturbation intensity that covaries positively with shell preservation. Dunes and palaeosols do not differ in species abundances despite differences in the degree of shell alteration, suggesting that both weakly and strongly altered assemblages offer data with a high compositional fidelity. Carbonate‐rich terrestrial deposits originating in arid conditions can enhance the preservation of gastropods and result in fossil assemblages that are suitable for palaeoecological and palaeoenvironmental studies of terrestrial ecosystems.     

Applications of nanoparticles in biology and medicine

Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Their unique size-dependent properties make these materials superior and indispensable in many areas of human activity. This brief review tries to summarise the most recent developments in the field of applied nanomaterials, in particular their application in biology and medicine, and discusses their commercialisation prospects.     

Specific toxic effects of 2,4,6-trinitrotoluene on Bacillus subtilis SK1

Using Bacillus subtilis SK1 as an example, it was demonstrated for the first time that 2,4,6-trinitrotoluene (TNT) transformation pathways change with TNT concentration. The growth of cultured B. subtilis SK1, delayed at 20 mg/l TNT (minimum toxic concentration), was resumed following TNT transformation. Aromatic amines were predominant metabolites detected in the culture medium at early stages of TNT transformation. The culture growth was completely inhibited by 200 mg/l TNT. As this took place, nitrites accumulated in the culture medium.     

Delayed biological consequences induced by gamma-radiation in human tumorigenic diploid line SK-UT-1B

The progeny of SK-UT-1B cells that survived gamma-irradiation with 4 Gy up to the 80th passage was examined. Descendants of irradiated cells lost p53 transactivation properties. Simultaneously, in the presence of nocodazole coordination between M and S phases was disrupted. Meanwhile, descendants of irradiated cells maintained the accurate spindle assembly checkpoint. These data suggest that p53 transactivation function may be required for coordination of M and S phases, rather than for spindle assembly checkpoint. Since it is known that p53 regulates both these processes on the basis of data obtained, we suggest that functions of p53 required for coordination of M and S-phases and for spindle assembly checkpoint are separated. Besides, the data obtained indicate that radiation-induced chromosomal rearrangements are associated with activation of DNA recombination process.     

Induced phytophthora resistance in transgenic potato tubers

Resistance of transgenic cultivars based on the expression of one or more resistance genes is sooner or later broken by pathogens whose race-producing rates are high. Thus, combining transgenesis with elicitor-induced resistance is a promising approach. The elicitor-induced resistance is based on the expression of multiple resistance genes, which can prevent the adaptation of pathogens to transgenic races, maintain the stability of cultivars, and increase their lifespan. In this work, we used transgenic potato cultivars Temp and Superior transformed with Bacillus thuringiensis delta-endotoxin gene and Lukyanovskii transformed with leukocyte alpha-interferon gene. Arachidonic acid (10(-8) M) and soluble chitosan (5 kDa, 100 micrograms/ml) were used as elicitors for tuber treatment. Our data showed that pretreatment with elicitors causes a 15-25% increase in both the systemic prolonged resistance of potato tubers to Phytophthora infestans and their ability to repair mechanical damage.     

Features of the toxic action of 2,4,6-trinitrotoluene on Escherichia coli K12

2,4,6-Trinitrotoluene present in a culture of Escherichia coli K12, at a concentration of 200 mg/l, caused a decrease in the total cell population and the population of colony-forming units, increased permeability of the external lipoprotein envelope, and increased the refractive index of cells. The shape of some cells changed from rod-like to coccoid, and cell size decreased. The specific rate of glucose consumption and the content of NADH (NADPH) in cells decreased. The changes of these morphological and physiological features were reversible, tending to normalize after reduction of 2,4,6-trinitrotoluene concentration in the course of cultivation.     

Use of monoclonal antibodies against horse immunoglobulin in an enzyme immunoassay of bacterial toxins and anatoxins

Immunization of BALB/c mice by horse antiserum against diphtheria made it possible to obtain IgG1 monoclonal antibodies (MoAbs) 2B7E4 specific for light chains of horse immunoglobulin (Ig). Unlike commercial preparations of anti-horse immunoglobulin antibodies, which are specific for the whole Ig molecule or its Fc-fragment, the peroxidase (HRP) conjugate of the MoAb, 2B7E4-HRP did not interact with human, mouse, rabbit, and sheep Igs, or horse albumin. The conjugate obtained was used with MoAbs against bacterial toxins and commercial horse anatoxins, as a universal reagent in sandwich enzyme immunoassay (ELISA) for bacterial toxins and anatoxins. The detection sensitivity of diphtheria toxin/anatoxin equaled 0.0005 Lf/ml; tetanus toxin and anatoxin were detected with sensitivities of 20 LD50/ml and 0.005 UI/ml, respectively. A similar sandwich ELISA for botulinum anatoxins (group measurement) allowed types A, B, and E to be detected at 0.02, 0.002, and 0.001 UI/ml, respectively; selective measurement was only possible in the case of type E anatoxin (0.001 UI/ml).     

Pentylenetetrazole kindling in rats: whether neurodegeneration is associated with manifestations of seizure activity?

Structural changes in neurons and oxidative stress in hippocampus were studied in rats "tolerant" (TR) and susceptible (SR) to tonic and clonic seizures in pentylenetetrazole (PTZ) kindling. The number of normal neurons was significantly decreased in CA1 subfield of TR hippocampus after 11 injections of PTZ, while in SR neuronal cell loss was evident in CA1 and fascia dentata. In both groups, neuronal cell loss was accompanied by increase in damaged neuron number in CA4 subfield. After 21 injections of PTZ, the decrease in normal neuron number was revealed in CA1 subfield of both TR and SR, while the number of damaged neurons was above the control level in hippocampal subfields CA1 and CA4 in TR only. Glutathione level was decreased in hippocampus of both TR and SR as compared with control rats. Thus, rats tolerant to PTZ-induced convulsions demonstrated oxidative stress and neurodegeneration in hippocampus. The results suggest that, in PTZ kindling model, oxidative damage of neurons resulting in neurodegeneration in hippocampus is not directly related to the convulsive activity.