Journal of Siberian Federal University 

About: Journal of Siberian Federal University is an academic journal. The journal publishes majorly in the area(s): Context (language use) & Population. Over the lifetime, 1261 publications have been published receiving 2888 citations.

Degradation of Polyhydroxyalkanoate (PHA): a Review

Abstract: Polyhydroxyalkanoate (PHA) is an attractive material due to its mechanical properties and biodegradability. As a result of its ability to degrade naturally in the environment, utilization of PHA is a step closer towards a greener environment with the aim of reducing the dependency on the nondegradable synthetic plastic. PHA is degraded by microorganisms that could secrete extracellular PHA depolymerase. Besides that, other factors that could affect the degradation of PHA include the environmental condition and the properties of PHA such as composition, crystallinity, additives and surface area of the PHA. This review provides a summary of intracellular and extracellular degradation, factors affecting the degradation of PHA and the application of PHA degradation.

Grafts of Woody Plants and the Problem of Incompatibility Between Scion and Rootstock (a review)

Abstract: Received 4.03.2011, received in revised form 11.03.2011, accepted 18.03.2011 Grafting can occur naturally between branches or more often roots of the same species, or artificially via asexual propagation where the tissues of two plants are encouraged to fuse with one another. Artificial grafting is commonly used for propagation to improve qualities of trees grown commercially via selecting for its roots (called the rootstock) and for stem, leaves, flowers or fruits (called the scion). It is often used to reduce the time to flowering and shorten the breeding program, improve quality and yield of fruits and seeds, improve hardiness in response to environmental conditions and pathogens resistance, and change cultivars. Incompatibility between rootstock and scion has been more often observed for inter-specific than intraspecific grafts, and might result in a dieback of a graft. The objective of this paper was to review the recent literature related to graft applications and incompatibility between scion and rootstock. Anatomical studies of incompatible grafts demonstrated a poor vascular connection, vascular discontinuity and phloem degeneration at the union area, which might be detected as early as few weeks after a graft establishment. These vascular fusion problems can disturb water, nutrient and assimilate flows in the plant and might result in a further breakdown of a union area. Incompatibility might be also a result of insufficient plasmodesmatal coupling at an early stage of development within one of the graft partners. Differences in abundance of phenol compounds and starch below and above the graft union, as well as peroxidase amount at the union might serve as biochemical markers of the rootstock/scion incompatibility. Genetically and biochemically similar scions and rootstocks could improve graft compatibility.

Silver nanoparticles as a new generation of antimicrobial prophylaxis

Abstract: Over the last 20 years, metallic silver in the form of Ag nanoparticles has made a remarkable comeback as an example of a nanomaterial for control of microorganisms. The purpose of our study was a) to quantitatively estimate the antimicrobial effect of silver nanoparticles compared with that of silver ions and b) to check the efficacy of nanosilver as an antimicrobial agent against a range of microbes on the surface of water-soluble paint, 100% cotton fabric, and fibrous chemisorbent. Minimum inhibitory concentration tests quantitatively showed that Ag nanoparticles were less efficient than Ag+ ions against representatives of gram-positive / gram-negative bacteria and cosmopolitan saprotrophic fungi. Antifungal/antibacterial effects against Aspergillus niger, Penicillium phoeniceum, and Staphylococcus aureus were confirmed for nanosilver concentrations of even 1 μg/cm2 on the surface of cotton fabric and 0.8 μg/cm2 in water-soluble paint. As the concentration of nanosilver in water-soluble paint/cotton fabric was increased to 7 μg/cm2, the growth of Bacillus subtilis and Escherichia coli was suppressed as well. Microbiological tests conducted over a period of 60 days showed that there was no biofilm growth on the surface of a silver nanoparticle-coated fiber sorbent during its everyday operation as a household water treatment filter. Thus, silver nanoparticles as an add-on to water-soluble paints, textile fabrics or fiber chemisorbents had a remarkable antibacterial/antifungal effect, although some of the Ag nanoparticles were agglomerated into larger colloidal clusters

Bioluminescent Bioassays Based on Luminous Bacteria

Abstract: Bioluminescent analysis is one of the most promising express methods for biologically monitoring the environment because the luminescent system is highly sensitive to even micro quantities of pollutants. Bioassays based on luminous bacteria give an integral estimation of toxicity and frequently surpass other known bioassays in speed, accuracy, sensitivity and simplicity. The enzymes of bacterial luminescent system are also used in developing highly sensitive analytical methods for practical purposes. This paper considers questions about the influence of different chemical substances on bacterial luminescence, development and using of bioluminescent bioassays. Luminous bacteria strains from the Culture Collection of Institute of Biophysics SB RAS (CCIBSO 836) are successfully used to produce new or improved microbiosensors based on lyophilized bacteria bearing the marker lux gene. Such biosensors are suitable for biotesting of water, air, soil, and the chemical substances used in everyday life. The \"know-how\" of kits for bioluminescent analysis and bioassays based on lyophilized natural luminous bacteria P.phosphoreum and recombinant Е.соli strain with cloned lux genes is developed. The bioluminescent assay has certificate and is recommended as an additional method of ecological monitoring in parallel with the other bioassays. The sensitivity of the biosensors developed in the IBP SB RAS is comparable to that of the foreign analogues Microtox ©TM , ToxAlert ©TM , etc.

Comparison of Effects of Uranium and Americium on Bioluminescent Bacteria

Abstract: Effect of UO2(NO3)2 on bioluminescent bacteria P.Phosphoreum was studied. It was compared with the effect of solutions of the more active radionuclide Am(NO3)3 studied earlier (Rozhko et al., 2007). Bioluminescence inhibition was observed under uranyl concentrations exceeding 10-7 M (30 Bq/l); and bioluminescence activation was not observed under all radionuclide concentrations and exposure times in the experiment. Effect of uranyl was attributed to chemical component of its impact, not radiation one. It was shown that solutions of Americium were detoxified by humic substances (0.25 mg/ml), but solutions of uranyl – are not.