Water permeability ofElodeacells and cytoplasm motion

The reduction of the rotational chloroplast motion velocity (CMV) during the exposure of Elodea cells to hypertonic solutions of PEG-4000 is satisfactorily described by an exponent. The dynamics of reduction correlates with the dynamic equilibration time (T_eq) between osmotic potentials of cell cytoplasm and external solution. The acceleration of the chloroplast motion, for example by gadolinium ions, results in the reduction of T_eq, and this is supposed to be due to the increase of the con tribution of the near-membrane Nernst layers to transmembrane transfer resistance resulting from the «blowing-off» of a part of the layer by moving cytoplasm.     

A novel mannitol teichoic acid with side phosphate groups of Brevibacterium sp. VKM Ac-2118.

The cell wall of Brevibacterium sp. VKM Ac-2118 isolated from a frozen (mean annual temperature -12 degrees C) late Pliocene layer, 1.8-3 Myr, Kolyma lowland, Russia, contains mannitol teichoic acid with a previously unknown structure. This is 1,6-poly(mannitol phosphate) with the majority of the mannitol residues bearing side phosphate groups at O-4(3). The structure of the polymer was established by chemical methods, NMR spectroscopy, and MALDI-TOF mass spectrometry.     

BIOLUMBASE--the database of natural and transgenic bioluminescent organisms.

The Institute of Biophysics SB RAS hosts and maintains a specialized collection of luminous bacteria (CCIBSO 836) containing over 700 strains isolated in various regions of the world's oceans. The culture collection is a source of lux genes and biologically active substances. The wide application of bioluminescence in medicine and ecology has given importance to analysing information on the structure and functioning of bioluminescence systems in natural and transgenic microorganisms, as well as on their features that are closely interrelated with bioluminescence. The aims of our BIOLUMBASE database are: gathering information on microorganisms with lux genes, their analysis and free access, and distribution of this data throughout the global network. The database includes two sections, natural and transgenic luminous microorganisms, and is updated by our own experimental results, the published literature and internet resources. For the future, a publicly available internet site for BIOLUMBASE is planned. This will list the strains and provide comprehensive information on the properties and functions of luminous bacteria, the mechanisms of regulation of bioluminescence systems, constructs with lux genes, and applications of bioluminescence in microbiology, ecology, medicine and biotechnology. It is noteworthy that this database will also be useful for evaluation of biological hazards of transgenic strains. Users will be able to carry out bibliographic and strain searches starting from any feature of interest.     

N-(5′-Phosphopyridoxyl)glutamic acid and N-(5′-phosphopyridoxyl)-2-oxopyrrolidine-5-carboxylic acid and their action on the apoenzyme of aspartate aminotransferase

1. N-(5'-Phosphopyridoxyl)-l-glutamic acid (P-Pxy-Glu, compound I) is readily converted at pH3 into a substance (P-Pxy-Glp, compound II) characterized as N-(5'-phosphopyridoxyl)-2-oxopyrrolidine-5-carboxylic acid. 2. The u.v., i.r. and fluorescence spectra of P-Pxy-Glu and P-Pxy-Glp have been determined; from the u.v. spectra their pK values have been found and compared. 3. The apoenzyme of aspartate aminotransferase is rapidly and irreversibly inactivated by P-Pxy-Glu, but is inactivated more slowly by P-Pxy-Glp. The complex with P-Pxy-Glp is stable enough to be isolated, but it is slowly reactivated in the presence of excess of pyridoxal phosphate. 4. The u.v. spectrum of the complex of apoenzyme and P-Pxy-Glp suggests that it contains a hydrogen bond between the phenolic hydroxyl group and the pyrrolidone nitrogen; this specifies the conformation of most of the molecule of P-Pxy-Glp. This conformation is similar to that previously postulated for the enzyme-glutamate complex except for the side chain of glutamate. Hence both the affinity of P-Pxy-Glp for the apoenzyme and the fact that it is more easily removed than P-Pxy-Glu are explicable.     

Azospirillum brasilense glutamine synthetase: influence of the activating metal ions on the enzyme properties

The kinetic properties of the Mg²⁺-activated and Mn²⁺-activated glutamine synthetase (GS) of Azospirillum brasilense in the biosynthetic reaction were studied. The Mg²⁺-supported and Mn²⁺-supported GSs in an average state of adenylylation varied in pH optimum, maximum activity, saturation functions for ammonium and glutamate, affinity to substrates, and in the Me²⁺-ATP ratio required for the optimal enzyme activity. Seventeen other cations were tested for the maintenance of GS activity. The level of the latter and the kinetic behavior of the GS in A.brasilense is suggested to depend essentially on the concentrations of Mg²⁺, Mn²⁺ and Co²⁺, as well as on their ratio     

Metabolomics of the human aqueous humor

Introduction

The optical elements of the eye—cornea, lens, and vitreous humor—are avascular tissues, and their nutrition and waste removal are provided by aqueous humor (AH). The AH production occurs through the active secretion and the passive diffusion/ultrafiltration of blood plasma. The comparison of the metabolomic profiles of AH and plasma is important for understanding of the mechanisms of biochemical processes and metabolite transport taking place in vivo in ocular tissues.

Objectives

The work is aimed at the determination of concentrations of a wide range of most abundant metabolites in the human AH, the comparison of the metabolomic profiles of AH and serum, and the analysis of the post-mortem metabolomic changes in these two biological fluids.

Methods

The quantitative metabolomic profiling was carried out with the use of two independent methods—high-frequency ¹H NMR spectroscopy and HPLC with high-resolution ESI-MS detection.

Results

The concentrations of 71 most abundant metabolites in blood serum and AH from living patients and human cadavers have been measured. It has been found that the level of ascorbate in AH is by two orders of magnitude higher than that in serum; the levels of other metabolites are either similar to that in serum, or differ from that by a factor of 2–5. The post-mortem metabolomic composition of both serum and AH undergoes rapid and strong changes.

Conclusion

The differences between the metabolomic profiles of AH and serum for majority of metabolites can be attributed to the metabolic activity of the ocular tissues leading to the lack or excess of some metabolites, while the high concentration of ascorbate in AH demonstrates the activity of ascorbate-specific pumps at the blood-aqueous border. The post-mortem metabolomic changes are caused by the disruption of the major biochemical cycles and cell lysis. These changes should be taken into account in the analysis of disease-induced changes in post-mortem samples of the ocular tissues.

     

Cytokine profiles of HIV patients with pulmonary tuberculosis resulting from adjunct immunotherapy with herbal phytoconcentrates Dzherelo and Anemin

Dzherelo (Immunoxel) and Anemin when combined with standard anti-tuberculosis therapy (ATT) were shown to produce better clinical outcome than chemotherapy alone. Sixty HIV-positive patients with active pulmonary TB were equally divided into three matched groups to receive either ATT, ATT + Dzherelo, or ATT + Dzherelo + Anemin. Peripheral blood samples were measured by ELISA for plasma levels of IL-2, IL-6, TNF-α, IFN-γ, and IFN-α. After 6 months of follow-up Dzherelo and Dzherelo + Anemin combinations produced 61% (P = 0.005) and 44.4% (P = 0.06) higher levels of IL-2, whereas in ATT group they were reduced by 33.1% (P = 0.002). The levels of IL-6 increased by 17% (P = 0.15) in ATT group, but declined in both immune intervention groups by 26.2% (P = 0.007) and 21.3% (P = 0.22). TNF-α was suppressed in two immunotherapy groups by 19.1% (P = 0.06) and 76.3% (P = 0.02), respectively, but had risen by 14% (P = 0.42) in ATT patients. The pattern of production of IFN-γ was opposite to that of TNF-α, but statistical significance was stronger in patients receiving ATT and Dzherelo + Anemin than in Dzherelo group: −34% (P = 0.004), +31.9% (P = 0.008), and +17.3% (P = 0.33), respectively. Moderately decreased levels of IFN-α were observed in all treatment arms (range 0.9–16.6%) but differences were not significant. Despite considerable intra-group variation in cytokine production, the baseline inter-group averages were not statistically different indicating that the results were not biased by sample heterogeneity. Immunomodulators used in this study possibly act by enhancing natural immune response against TB. Expanded study of other cytokines and correlates relevant to control and protection from TB and HIV is needed in order to identify biomarkers of favorable treatment outcome, which may aid design of better immune interventions and vaccines.