Interaction of fibronectin with polymorphonuclear leukocytes normally and in anaphylaxis

Fibronectin is known as an opsonic glycoprotein possessing a wide range of specificity. Fibronectin interaction with neutrophils (normal ones and those obtained at peak of anaphylactic shock) was studied. Neutrophils were brought in contact with purified homologous fibronectin previously bound to gelatin-Sepharose granules. The presence of fibronectin-binding proteins on the surface of human and rabbit neutrophils was demonstrated, the binding being strongly dependent on Ca2+ and especially Mg2+ ions. "Anaphylactic" neutrophils, in contrast to normal ones, did not interact with fibronectin, which may be important for the pathogenesis of the immediate type hypersensitivity reactions.     

Cloning, production and characterisation of wild type and mutant forms of the R.EcoK endonucleases.

The hsdR, hsdM and hsdS genes coding for R.EcoK restriction endonuclease, both with and without a temperature sensitive mutation (ts-1) in the hsdS gene, were cloned in pBR322 plasmid and introduced into E.coli C3-6. The presence of the hsdSts-1 mutation has no effect on the R-M phenotype of this construct in bacteria grown at 42 degrees C. However, DNA sequencing indicates that the mutation is still present on the pBR322-hsdts-1 operon. The putative temperature-sensitive endonuclease was purified from bacteria carrying this plasmid and the ability to cleave and methylate plasmid DNA was investigated. The mutant endonuclease was found to show temperature-sensitivity for restriction. Modification was dramatically reduced at both the permissive and non-permissive temperatures. The wild type enzyme was found to cleave circular DNA in a manner which strongly suggests that only one endonuclease molecule is required per cleavage event. Circular and linear DNA appear to be cleaved using different mechanisms, and cleavage of linear DNA may require a second endonuclease molecule. The subunit composition of the purified endonucleases was investigated and compared to the level of subunit production in minicells. There is no evidence that HsdR is prevented from assembling with HsdM and HsdSts-1 to produce the mutant endonuclease. The data also suggests that the level of HsdR subunit may be limiting within the cell. We suggest that an excess of HsdM and HsdS may produce the methylase in vivo and that assembly of the endonuclease may be dependent upon the prior production of this methylase.     

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.     

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.     

Characteristics of antitoxic and antibacterial immune response in nontoxic forms of oropharyngeal diphtheria

The enzyme immunoassay system (EIA) for differentiation of antibodies in therapeutic heterogeneous antitoxic serum and antibodies to Corynebacterium diphtheriae toxigenic strains in patients and carriers was developed. The use of EIA permitted the dynamic evaluation of the characteristics of humoral antitoxic and antibacterial immune response in 50 patients with the localized and disseminated forms of stomatopharyngeal diphtheria and 14 "healthy" carriers of toxigenic C. diphtheriae. As revealed in this study, the symptoms of the disease in patients with disseminated forms of stomatopharyngeal diphtheria developed in the presence of statistically significant low quantitative values of antitoxic and antibacterial antibodies to C. diphtheriae antigens. In the group of patients with the localized forms of the disease the initially low level of antitoxic antibodies was detected with the concentration of antibacterial antibodies remaining unchanged. During the period of convalescence the levels of antitoxic antibodies in both groups reached those of healthy persons. In case of localized forms of the disease the level of antibacterial antibodies decreased as compared with healthy persons, starting from the second week of the disease. The period of convalescence in the disseminated forms was characterized by the low concentration of antibacterial antibodies. Carrier state was formed in the presence of high levels of antitoxic antibodies and significantly low levels of antibacterial ones.     

The effect of Pseudomonas NCIMB 2021 biofilm on AISI 316 stainless steel

A bioreactor system operating in a continuous mode was designed to generate biofilms on polished and as-received surfaces of AISI 316 stainless steel coupons exposed for 36 d to a pure culture of marine Pseudomonas NCIMB 2021. Scanning electron microscopy (SEM) and atomic force microscopy were employed to determine the degree of surface colonisation and to examine corrosion damage of the steel. X-ray photoelectron spectroscopy analysis was carried out to characterise the chemistry of the passive layers on polished steel stored for a period of time, freshly re-polished coupons, and as-received steel. The effect of biofilms on the composition of layers formed on the steel specimens was evaluated. SEM revealed that the surfaces of polished and stored steel appeared to accumulate more biofilm compared to as-received specimens. Micropitting of steel occurred underneath the biofilm, regardless of surface finish. The concentration of elements in the passive layers differed significantly between freshly re-polished and as-received or polished and stored coupons. In the presence of Pseudomonas NCIMB 2021 biofilm, the composition of the passive layer on the as-received steel surface was considerably altered compared to unexposed steel or steel exposed to abiotic medium.     

Effect of dopamine antibodies on neuropathic pain syndrome in rats

Dopaminergic brain system plays an important role in regulation of pain sensitivity. However, the data on participation of antidopamine antibodies in the development of neurogenic pain are absent. This work was aimed at the study of the role of antidopamine antibodies in the development of pain syndrome induced by the injury of nn. ischiadic and saphenous in rats. It was shown that after the nerve injury, the behavioral reaction such as autotomy (self-injury) appeared as a feature of the experimental neuropathic pain syndrome. It was originally established that the development of neuropathic pain syndrome induced by the injury of peripheral nerves was accompanied by induction of dopamine autoantibodies. It was also shown that immunization of the animals with conjugated dopamine-protein autigen resulted in aninerease of autidopamine antibody level and an amplification of the experimental neuropathic pain syndrome, i.e., decrease in the latency of the first autotomy, increase in expression of autotomies, and increase in the number of animals with late autotomies.     

The relation of the X-ray B-factor to protein dynamics: insights from recent dynamic solid-state NMR data

In addressing the potential use of B-factors derived from X-ray scattering data of proteins for the understanding the (functional) dynamics of proteins, we present a comparison of B-factors of five different proteins (SH3 domain, Crh, GB1, ubiquitin and thioredoxin) with data from recent solid-state nuclear magnetic resonance experiments reflecting true (rotational) dynamics on well-defined timescales. Apart from trivial correlations involving mobile loop regions and chain termini, we find no significant correlation of B-factors with the dynamic data on any of the investigated timescales, concluding that there is no unique and general correlation of B-factors with the internal reorientational dynamics of proteins.