Efficiency and Mechanisms of Bactericidal Effect of Superhydrophilic Magnesium Alloy Surface against Escherichia coli

Microbiology - The surface of the MA8 magnesium alloy, modified by laser treatment, was found to acquire superhydrophilic properties and high bactericidal activity against Escherichia coli K12...     

Molecular forms of alpha-1-acid glycoprotein in human blood serum. Differences in levels of di-, tri-, and tetra-antennary N-linked carbohydrate chains]

alpha 1-Acid glycoprotein isolated from healthy individuals blood was separated on Con A-Sepharose into three fractions: non-bound (AGP-1, 84%, 43.5 kDa), Con A-bound (AGP-2, 14%, 41.3 kDa), and Con A-tightly bound (AGP-3, 2%, 39.6 kDa). Amino acid compositions of these fractions were similar but carbohydrate ones differed. HPLC analysis of 7-amino-4-methylcoumarin derivatives of the oligosaccharides in combination with their sequential exoglycosidase digestion showed that AGP-1, AGP-2, and AGP-3 have the same set of oligosaccharides and differ only by their proposition. A minor quantity of agalacto-oligosaccharides (with a terminal GlcNAc residue) was identified.     

Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves

The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –¹⁴CO₂ fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes.     

SOS-induction of the RP4 plasmid tet-determinant

Induction of the tetracycline-resistance genes function by the inducer of the DNA-repair and mutability SOS-system, UV-light, has been tested. Activity of the tet-genes residing on the plasmid RP4 in Escherichia coli cells has been shown to be inducible by the low doses of tetracycline as well as by the mutagenic doses of UV-light. The induction was quantitatively registered by measuring the activity of beta-galactosidase of bacteriophage Mud1 (Ap, Lac) inserted into the tet-genes of the plasmid RP4. The bacteriophage integration inactivates the tet-genes function of the constructed plasmid fusing the lac-operon to a promoter of inactivated genes. Precise excision of bacteriophage restores the activity of the tet-genes proving together with the plasmid DNA-restriction analysis the fusion of tet-promoter with Iac-operon. The tet-genes of RP4 are concluded to be a part of the SOS-regulon, a set of genes inducible by the conditions harming the bacterial cell. Preliminary data on the mutagenic activity of tetracycline obtained in the bacterial test-system of mutagens are discussed.     

Lecithotrophic development and metamorphosis in the Indo-West Pacific brittle star Ophiomastix venosa (Echinodermata: Ophiuroidea)

Summary

The larval development of the ophiocomid ophiuroid Ophiomastix venosais described using SEM. The gastrula transforms into a uniformly ciliated early larva which progressively changes into a lecithotrophic late premetamorphic larva with a continuous bilateral ciliated band. This stage is short-lived and equivalent to a highly reduced ophiopluteus. Comparisons between O. venosa and other ophiuroid species whose development has been investigated suggest that, whatever the developmental mode (lecithotrophic or planktotrophic), a pluteus stage always occurs in ophiuroids with planktonic development. Two metamorphic stages were identified, the late metamorphic larva differing from the early one by the closure of the larval mouth. The appearance of the permanent mouth marks the end of the metamorphosis. The postlarva still possesses remnants of larval features. The transformation of the reduced ophiopluteus into a barrel-shaped metamorphic larva with transverse ciliated bands, a vitellaria larva, is followed. The possible occurrence of a unique type of metamorphic larva in non-brooding ophiuroids is discussed. Verification of this, however, needs further SEM investigations on metamorphic larva from species having “regular” planktotrophic development.     

Specific biological features of opportunistic bacteria determining dysbacteriosis in the composition of the large intestine normal microflora

Dysbiotic manifestations in the gastrointestinal tract are widely spread. They are characterized by a prolonged, persistent course with the tendency to transition to the chronic form and poorly respond to corrective treatment. The occurrence of high concentrations is 70% for Klebsiella oxytoca, while for K. pneumoniae--within the limit of 30%. The most topical problem is colonization of the intestinal mucosa in children aged up to 1 year by Klebsiella, the seeded bacteria retaining their capacity for growth for up to 2-3 years despite the use of probiotics. As shown in this study, the occurrence of Klebsiella and the level of the antilysozyme and "antiinterferon" activity of these bacteria, their resistance to antimicrobial preparations increase, correlating with the level of dysbiotic disturbances.     

Interferon therapy of infectious diseases: the state of the problem and prospects

The data contained in literature and obtained in our own investigations, aimed at the evaluation of the significance of interferon preparations for the correction of immunological disturbances are presented. A special place is given to the role of mild medicinal forms of interferon, the necessity of their use is grounded and good prospects for their inclusion into the complex therapy of infectious diseases are shown.     

Influence of cytokine preparations on the in vitro resistance of bacteria to antibiotics

Recombinant tumor necrosis factor-alpha and gamma-interferon were found in vitro to increase the sensitivity of bacteria to antibiotics both alone and in combination; alpha2-interferon decreased this sensitivity.     

Modern methods of laboratory diagnostics of Chlamydia infections

Need for further improvement of methods for verification of etiological agent of urogenital and respiratory chlamydiosis on the basis of increased biotechnological requirements to antigens for serological reactions, primers for PCR assay (refinement of connection of primers with microorganism's zones of genome most significant for its life activity or formation of most diagnostically significant complexes of primers), and selection of cultivating conditions considering the predicted features of clinical strains of the agent was substantiated.