The alternative oxidase of Yarrowia lipolytica mitochondria is unable to compete with the cytochrome pathway for electrons

The activity of the cyanide-resistant alternative oxidase (pathway) of Y. lipolytica mitochondria was studied as a function of the activity of the major, cyanide-sensitive, cytochrome pathway. The contribution of the alternative oxidase to the total respiration of mitochondria was evaluated by measuring the rate of oxygen consumption in the presence of cyanide (an inhibitor of the cytochrome pathway). The potential activity of the cytochrome pathway was evaluated spectrophotometrically, by measuring the oxidation rate of cytochrome c by ferricyanide, which accepts electrons from complex III (cytochrome c) of this pathway. The oxidation of succinate by mitochondria in the presence of ferricyanide and cyanide was accompanied by oxygen consumption due to the transfer of electrons through the alternative pathway. The subsequent addition of ADP or FCCP (an uncoupler of oxidative phosphorylation in the cytochrome pathway) completely inhibited the consumption of oxygen by the mitochondria. Under these conditions, the inhibition of the alternative pathway by benzohydroxamic acid failed to affect the transfer of electrons from cytochrome c to ferricyanide. Benzohydroxamic acid did not influence the rate of ferricyanide reduction by the cytochrome pathway occurring in controlled state 4, nor could it change the phosphorylation quotient ATP/O upon the oxidation of various substrates. These findings indicate that the alternative pathway is unable to compete with the cytochrome respiratory chain for electrons. The alternative pathway transfers only electrons that are superfluous for the cytochrome chain.     

Characteristics of radish lines and hybrids from the spectrum of multiple molecular forms of enzymes

We characterized radish lines from a genetic collection on the basis of six enzyme systems, identified genes controlling these enzymes, and examined joint inheritance of some biochemical and morphological traits.     

Sequential isolation of superoxide dismutase and ajmaline from a tissue culture of Rauwolfia serpentina Benth

Two biologically active compounds, the enzyme superoxide dismutase (EC 1.15.1.1) and the antiarrhythmic indole alkaloid ajmaline, were isolated from a callus culture of Rauwolfia serpentina Benth. Sequential isolation of biologically active compounds by metal-chelate affinity chromatography followed by azoadsorbent affinity chromatography allowed us to obtain highly purified products. The yields of superoxide dismutase and ajmaline were 180 mg/kg biomass and 16.5 g/kg dry weight, respectively.     

Use of celluloselytic nitrogen-fixing bacteria in the enrichment of roughage with protein

A new strain of acid-tolerant facultative anaerobic cellulose-degrading bacteria Bacillus cytaseus 21 (Mc Bethe ef Scales, 1912), which are capable to fixing atmospheric nitrogen, was isolated. This strain is intended for solid-phase fermentation and enrichment with protein of cellulose-containing waste of plant cultivation.     

Ontogeny of different life forms of plants and specific features of age and spatial structure of their populations

Materials have been generalized that were accumulated in population-ontogenetic studies of plants and leading features of the ontogeny of plants have been noted that determine specific structural features of their populations. The described patterns allowed the authors to develop simulation models of plant population dynamics. The results of simulation are provided, and they are compared to the empirical data. Problems have been considered that concern the influence of specific features of development of different plant biomorphs on the genetic structure of populations and biocoenotic processes.     

Disruption of organization of mitotic microtubules in root meristem cells of Allium cepa induced by chloral hydrate

Data are presented on the effect of chlorahydrate on microtubule organization in the root meristem of Allium cepa. Our studies show that an incomplete preprophase band commonly appears during G2-prophase transition, yet the major effect is the lack of perinuclear microtubules, leading to inhibition of the prophase spindle formation and transition to C-mitosis. Upon chloralhydrate treatment of metaphase cells, we found cells with chromosomes regularly aligned within the metaphase plate and differently disorganized mitotic spindles. Concurrently, C-metaphase cells with remnants of kinetochore fibers were present. In addition, normal bipolar and abnormal irregular types of chromosome segregation were detected, this representing multipolar and diffuse anaphases. The major difference between them is the presence of polar microtubules during multipolar anaphase, and their lacking during diffuse anaphase. Alternatively, microtubule clusters between segregated groups of chromosomes are typical for cells with diffuse anaphase. During bipolar anaphase, excessive aster-like microtubules emanate from the spindle poles, and in telophase accessory phragmoplasts are observed at the cell periphery. The formation of incomplete phragmoplasts was observed after normal bipolar and abnormal chromosome segregation. We conclude that chloralhydrate may affect the nuclear surface capability to initiate the growth of perinuclear microtubules, thus blocking the prophase spindle formation. It also disturbs the spatial interaction between microtubules, which is crucial for the formation and functioning of various microtubular systems (preprophase band, spindle and phragmoplast).     

Prototype symbolization in hooded crows

The ability in prototype symbolization was studied in four crows trained in matching concept. The experimental approach was characterized by the absence of direct training providing an association between the pictured arrays and Arabic numerals. Experimental sessions were divided into demonstrative and test phases. In the demonstrative phases, the sample and the reinforced stimulus belonged to the same category: if the sample was a pictured array, the reinforced stimulus was also the pictured array, if the sample was a numeral, the reinforced stimulus was likewise a numeral. Matching-to-sample competence was sufficient to perform this task successfully. In case of a correct choice a crow received some mealworms, their number was equal to the number of items in the pictured array or the Arabic numeral. In the test phases, the sample and the comparison stimuli were of different categories. If the sample was a pictured array, the comparison stimuli were numerals; if the sample was a numeral, the comparisons were the pictured arrays. Such tests required the birds to choose a numeric symbol corresponding to the pictured array or to choose the array of pictured items numerically equal to the Arabic symbol. All four crows performed this task successfully. Birds were able to set up a correspondence between the Arabic numeral from 1 to 4 and the number of elements in pictured arrays by way of mental juxtaposition of the earlier received information. Similar experiments showed that crows are likely to be able to perform mental operations with numerals analogous to simple arithmetic addition.     

Role of the pro-inflammatory cytokines tumor necrosis factor-alpha,interleukin-1 beta,interleukin-6 and interleukin-8 in the pathogenesis of the otitis media with effusion

Inflammation in the middle ear mucosa, caused usually by bacterial and viral pathogens, is the primary event in the middle ear predisposing the development of otitis media with effusion (OME). Numerous inflammatory mediators have been identified in OME. However, cytokines play a central role as initiators, mediators and regulators of middle ear inflammation and subsequent molecular-pathological processes in middle ear tissues, leading to histopathological changes in the middle ear cavity and the pathogenesis of OME. In this article, we aim to present an overview of current research developments in the pro-inflammatory cytokine involvement in the aetiology of otitis media with effusion.