Degradation of 2-chlorobenzoic and 2,5-dichlorobenzoic acids in soil columns byPseudomonas stutzeri

The heterocontinuous flow cultivation technique was used for the study of 2-chlorobenzoic and 2,5-dichlorobenzoic acid degradation in soil columns inoculated withPseudomonas stutzeri. 2-Chlorobenzoic and 2,5-dichlorobenzoic acids disappeared from the soil columns within 8 and 12 d, respectively. The presence of the haloaromatics increased the survival of strain KS25 in soil. Viable cell numbers in the soil columns flushed with 2-chlorobenzoic and 2,5-dichlorobenzoic acids were 1.3 and 2 times higher, respectively, than those without the chlorobenzoic acids after 30 d of incubation.     

Is cobalt-binding capacity of serum a new perspective diagnostic marker?

The aim of this study was to determine the reference interval of serum cobalt-binding capacity (CoBC), and to estimate the effect of factors unrelated to oxidative modification of serum albumin on this diagnostic marker. Healthy volunteers (n = 194), patients with autoimmune diseases (n = 44) and patients with type 2 diabetes mellitus (n = 50) were enrolled in the study. The regional reference interval was found to be 0,462–0,744 mmol Co²⁺/L of serum. The study of serum CoBC in patients with autoimmune pathology and type 2 diabetes mellitus has shown that the CoBC level strongly depends on the serum protein profile. Therefore, this test may be used to diagnose the ischemia, although other pathologies associated with changes in the ratio of blood protein fractions can also influence the serum CoBC level.     

Use of mini-antibodies for detection of bacteriophages by the electroaucoustic analysis method

The possibility of detecting bacteriophages using phage mini-antibodies by the electroacoustic analysis method using bacteriophages FA1-59b was shown. It was found that the frequency dependence of the real and imaginary parts of the electrical impedance of a resonator with a suspension of phages and the appropriate antibodies significantly differs from that of the resonator with a control virus suspension without addition of mini-antibodies. The amount of FAl-Sp59b bacteriophage in the analyzed suspension varied from ~10¹⁰ to 10⁶ phage/mL; the analysis did not take longer than 5 min. The change in the real or imaginary parts of the electrical impedance at the fixed frequency near the resonance after addition of specific mini-antibodies in the suspension appeared to be an optimal information parameter to obtain reliable information. These results may allow the development of a biological sensor to identify and quantify viruses in the liquid phase.     

Hoarding patterns of sigmodontine rodent species in the Central Monte Desert (Argentina)

Hoarding food is an important strategy of rodents in desert environments characterized by unpredictable and poor food resource availability. In the Monte Desert, Prosopis produces abundant food, unevenly in time and space, in the form of pods and seeds. Sigmodontine rodents (Graomys griseoflavus, Akodon molinae, Eligmodontia typus and Calomys musculinus) use Prosopis propagules extensively, and they could be predators or dispersers depending on how they handle and where they leave the propagules. The objectives of this study were: (1) to know what rodent species transported propagules; (2) to evaluate what hoarding pattern was used by species that transport propagules (larder and scatterhoarding); and (3) to analyse in which condition were propagules left by the rodent species, both at the food source and in caches. Our results showed that all four species transported propagules, with G. griseoflavus and E. typus being the species that carried more seeds. Our study supported the evidence that food caching is common among species and that many species both larderhoard and scatterhoard food. Graomys griseoflavus and A. molinae, the largest species, larderhoarded more than did the smaller E. typus. These results uphold the hypothesis that larger species will show greater propensity to larderhoard than smaller species. Considering the interaction between seed‐hoarding patterns and plants, E. typus was the species that could most improve germination because it scatterhoarded propagules and left seeds out of pods. In contrast, G. griseoflavus could have a negative impact on plant populations because this was the species that predated more seeds and larderhoarded a high percentage of them. The smallest C. musculinus was the species that transported propagules least, and left them as seeds inside pods or pod segments mainly at the food source, which makes seeds more vulnerable to predation.     

To the analytical theory of the supercompensation phenomenon

The effect of supercompensation and the conditions of its origination have been analyzed using a special analytical solution of the equation of the overdamped Duffing oscillator. The threshold values of the functional shift after the exposure of a living organism to intensive external load have been found. If these values are exceeded, the restoration process goes through the stages of enhanced and lowered working capacity. Expressions for the times of transition to these phases after the onset of recovery and for the time of occurrence of the maxima of these phases have been obtained and analyzed.     

Obtaining phage mini-antibodies and using them for detection of microbial cells with an electroacoustic sensor

Phage mini-antibodies to bacterial cells of strain Azospirillum brasilense Sp245 were obtained, and the possibility of using them for detection of microbial cells with a lateral field excited piezoelectric resonator was studied. It has been found that the frequency dependences of the real and imaginary parts of electrical impedance of such a resonator loaded with a suspension of A. brasilense Sp245 cells with the mini-antibodies differ significantly from the dependences of the resonator with a control cell suspension without mini-anti-bodies. The limit of possible determination of the concentration of microbial cells is found to be 10³ cells/mL upon interaction with mini-antibodies. It has been ascertained that detection of A. brasilense Sp245 cells with the aid of mini-antibodies is possible even in the presence of other cultures, for example, E. coli BL-Ril and A. brasilense Sp7. Therefore, it has been shown for the first time that detection of microbial cells with an electroacoustic sensor is feasible.     

Fungal Azaphilone Pigments as Promising Natural Colorants

Microbiology - Microscopic fungi form and excrete numerous and diverse secondary metabolites, including pigments of various colors, which may be used as an alternative to chemical and plant...     

Receptor elements for biosensors in two ways of methylotrophic yeast immobilization

Receptor elements for biosensors based on Hansenula polymorpha NCYC 495 ln yeast cells for ethanol assay were developed using two ways of cell immobilization, i.e., physical adsorption on a glass fiber membrane and covalent binding on a modified nitrocellulose membrane. The linear diapason of ethanol assays for a biosensor based on yeast cells adsorbed on glass fiber was 0.05–1.18; for a biosensor based on yeasts immobilized on a nitrocellulose membrane, 0.2–1.53 mM. Receptor elements based on sorbed cells possessed 2.5 times higher long-term stability. The time response was 1.5 times less for cells immobilized using DEAE-dextran and benzoquinone. The results of ethyl alcohol assays using biosensors based on cells immobilized via adsorption and covalent binding, as well as using the standard areometric method, had high correlation coefficients (0.998 and 0.997, respectively, for the two ways of immobilization). The results indicate the possibility to consider the described models of receptor elements for biosensors as prototypes for experimental samples for practical use.     

Degradation of 2-chlorobenzoic and 2,5-dichlorobenzoic acids in pure culture byPseudomonas stutzeri

A strain ofPseudomonas stutzeri KS25 utilizing 2-chlorobenzoic and 2,5-dichlorobenzoic acids as the sole carbon and energy source was isolated from polychlorophenol-contaminated soil and sewage, using the method of enrichment cultures. This strain was also able to grow on 2-fluoro-, 2-iodo-, 2-bromo- and 2,5-dihydroxybenzoate, but did not utilize 3-, 4-chloro-, 2,4- and 2,6-dichlorobenzoates as the sole carbon and energy source, however, it cometabolized 3-chloro-, 2,4-and 2,6-dichlorobenzoates, but not 4-chlorobenzoate. The yield of released chlorine during utilization of 2-chloro- and 2,5-dichlorobenzoates amounted to 100 % of the theoretical. The concentration of 2-chloro- and 2,5-dichlorobenzoates, not substantially inhibiting the isolated microorganism, was within the range 0.25–0.5 and 2.5–3.0 g/L, respectively.