Effects of prolonged hyperbarism on lipid peroxidation and structural-functional state of erythrocytes]

Prolonged helium-oxygen hyperbaric (pressure 3,6 MPa) increased diene conjugate and Schiff's base level in plasma and erythrocyte membranes of mice. In those conditions SOD and glucose 6-phosphate dehydrogenase activities were inhibited in erythrocytes. Lipid bilayer microviscosity and cholesterol content of erythrocyte membranes were increased.     

Elimination of Aspergillus fumigatus conidia from the airways of mice with allergic airway inflammation

Background

Aspergillus fumigatus conidia can exacerbate asthma symptoms. Phagocytosis of conidia is a principal component of the host antifungal defense. We investigated whether allergic airway inflammation (AAI) affects the ability of phagocytic cells in the airways to internalize the resting fungal spores.

Methods

Using BALB/c mice with experimentally induced AAI, we tested the ability of neutrophils, macrophages, and dendritic cells to internalize A. fumigatus conidia at various anatomical locations. We used light microscopy and differential cell and conidium counts to determine the ingestion potential of neutrophils and macrophages present in bronchoalveolar lavage (BAL). To identify phagocyte-conidia interactions in conducting airways, conidia labeled with tetramethylrhodamine-(5-(and-6))-isothiocyanate were administered to the oropharyngeal cavity of mice. Confocal microscopy was used to quantify the ingestion potential of Ly-6G⁺ neutrophils and MHC II⁺ antigen-presenting cells located in the intraepithelial and subepithelial areas of conducting airways.

Results

Allergen challenge induced transient neutrophil recruitment to the airways. Application of A. fumigatus conidia at the acute phase of AAI provoked recurrent neutrophil infiltration, and consequently increased the number and the ingestion potential of the airway neutrophils. In the absence of recurrent allergen or conidia provocation, both the ingestion potential and the number of BAL neutrophils decreased. As a result, conidia were primarily internalized by alveolar macrophages in both AAI and control mice at 24 hours post-inhalation. Transient influx of neutrophils to conducting airways shortly after conidial application was observed in mice with AAI. In addition, the ingestion potential of conducting airway neutrophils in mice with induced asthma exceeded that of control mice. Although the number of neutrophils subsequently decreased, the ingestion capacity remained elevated in AAI mice, even at 24 hours post-conidia application.

Conclusions

Aspiration of allergen to sensitized mice enhanced the ingestion potential of conducting airway neutrophils. Such activation primes neutrophils so that they are sufficient to control dissemination of non-germinating A. fumigatus conidia. At the same time, it can be a reason for the development of sensitivity to fungi and subsequent asthma exacerbation.     

Element Concentrations in Some Species of Seaweeds from La Paz Bay and La Paz Lagoon, South-Western Baja California, Mexico

La Paz Bay and La Paz Lagoon are water bodies of the Gulf of California that are influenced by waste water discharges from the City of La Paz and from activities of the phosphorite mining company “Rofomex”. Because seaweeds concentrate elements from the water and are used as effective indicators of contamination by metals, we investigated their usefulness in this region. Concentrations of certain major elements (Ca, Fe, K and Na) and trace elements (As, Ba, Co, Cr, Cs, Hf, Rb, Sb, Sc, Se, Sr, Ta, Th, U, Zn and Zr) were determined in 12 species of seaweeds from La Paz Bay and La Paz Lagoon using instrumental neutron activation analysis. The contents of trace elements of environmental importance (As, Co, Cr, Fe, Sb, Se and Zn) in all studied samples are within the range of typical levels for a pristine environment not subjected to anthropogenic impact. Somewhat higher concentrations of Cr (81mg kg⁻¹), Hf (4mg kg⁻¹), Rb (48mg kg⁻¹), Sc (6.3mg kg⁻¹), Ta (0.95mg kg⁻¹), Th (6.8mg kg⁻¹), U (33mg kg⁻¹) and Zn (90mg kg⁻¹) were found in the green seaweed species Ulva (formerly Enteromorpha) intestinalis, whereas such elements as As (77mg kg⁻¹), Sb (1.4mg kg⁻¹) and Se (1.8mg kg⁻¹) were mainly concentrated in the species Sargassum sinicola, Codium cuneatum and Padina mexicana respectively. Because of their higher abundance and heterogeneity in elemental composition the seaweeds species Ulva intestinalis and Caulerpa sertularioides seem to be more suitable for further biomonitoring of heavy metal pollution of the coastal waters in this zone.     

The Perfect Burrow,but for What? Identifying Local Habitat Conditions Promoting the Presence of the Host and Vector Species in the Kazakh Plague System

Introduction

The wildlife plague system in the Pre-Balkhash desert of Kazakhstan has been a subject of study for many years. Much progress has been made in generating a method of predicting outbreaks of the disease (infection by the gram negative bacterium Yersinia pestis) but existing methods are not yet accurate enough to inform public health planning. The present study aimed to identify characteristics of individual mammalian host (Rhombomys opimus) burrows related to and potentially predictive of the presence of R.opimus and the dominant flea vectors (Xenopsylla spp.).

Methods

Over four seasons, burrow characteristics, their current occupancy status, and flea and tick burden of the occupants were recorded in the field. A second data set was generated of long term occupancy trends by recording the occupancy status of specific burrows over multiple occasions. Generalised linear mixed models were constructed to identify potential burrow properties predictive of either occupancy or flea burden.

Results

At the burrow level, it was identified that a burrow being occupied by Rhombomys, and remaining occupied, were both related to the characteristics of the sediment in which the burrow was constructed. The flea burden of Rhombomys in a burrow was found to be related to the tick burden. Further larger scale properties were also identified as being related to both Rhombomys and flea presence, including latitudinal position and the season.

Conclusions

Therefore, in advancing our current predictions of plague in Kazakhstan, we must consider the landscape at this local level to increase our accuracy in predicting the dynamics of gerbil and flea populations. Furthermore this demonstrates that in other zoonotic systems, it may be useful to consider the distribution and location of suitable habitat for both host and vector species at this fine scale to accurately predict future epizootics.     

Construction of the plasmid for expression of ETA-EGFP fusion protein under control of the cytomegalovirus promoter and its effects in HeLa cells

Tumor-targeted vectors encoding toxic protein genes are promising tools for treating malignant tumors. We used the pEGFP-N1 vector to construct a novel plasmid (pCMV-ETA-EGFP) for eukaryotic expression of a truncated Pseudomonas aeruginosa exotoxin A (ETA) that is known to inhibit protein synthesis, and subsequently induce cell death, by inactivation of elongation factor-2. ETA was linked to the enhanced green fluorescent protein (EGFP) gene, and ETA-EGFP gene expression was driven by the cytomegalovirus (CMV) promoter. The time-lapse effects of pCMV-ETA-EGFP expression were examined in transiently transfected HeLa cells. HeLa cells transfected with pCMV-ETA-EGFP or cotransfected with pCMV-ETA-EGFP and рЕGFP-N1 showed lower fluorescence intensity than cells transfected with pEGFP-N1 alone. Analysis of the number of dead cells further confirmed the highly toxic effect of the ETA-EGFP fusion protein on cells transfected with pCMV-ETA-EGFP or cotransfected with pCMV-ETA-EGFP and рЕGFP-N1. ETA-EGFP fusion protein induced apoptotic cell death through the caspase-3 activation. By using the antibody against a marker nucleolar antigen A3 [Grigoryev, A.A., Bulycheva, T.I., Sheval, E.V., Kalinina, I.A., Zatsepina, O.V., 2008. Cytological indicators of the overall suppression of protein synthesis revealed by staining with new monoclonal antibody. Cell Tissue Biol. 2, 191–199], the distribution of which changes when HeLa cells are treated with known translation inhibitors, we obtained evidence to support the idea that protein synthesis is inhibited in transfected cells in situ. ETA-EGFP fusion protein was identified in lysates of transfected cells using anti-GFP-BL antibodies. Collectively, our results indicate that HeLa cells transfected with pCMV-ETA-EGFP synthesize the ETA-EGFP fusion protein that efficiently inhibits protein synthesis, leading to massive cell death by an apoptosis-mediated pathway with a participation of caspase-3. The constructed vector can be used in suicidal gene therapy of cancer and may also be useful for investigating the general effects of translational downregulation in human cancer cells. We also suggest a novel approach for detecting the activity of new vectors in transfected cells, which is based on the redistribution of nucleolar proteins in transfected cells.     

Immunosuppressive activity of glycosphingolipids. Influence of serum factors on ganglioside inhibition of IL-4-dependent cell proliferation.

Gangliosides have been shown to inhibit proliferation of the interleukin-4 (IL-4) responsive cell line CT.4R. Kinetic analysis has revealed that ganglioside GT1b is a competitive inhibitor of proliferation, while GM and GM3 show a mixed pattern of inhibition, i.e., exhibit more than one inhibition type. Contribution of the competitive cell inhibition for GM1 and GM3 depends on serum factors added: the higher is the percentage of FCS, the larger is the contribution of competitive inhibition. The pattern of proliferation inhibition shown for GT1b does not depend on the FCS content. We have also studied the interaction of the recombinant IL-4 with fluorescent (anthrylvinyl-labelled) gangliosides GM1 and GM3 and lactosylceramide incorporated into liposomes. Dissociation constants of the IL-4-ganglioside complexes have been determined; lactosylceramide does not interact with rIL-4. The K(d) values for the lymphokine complexes with gangliosides support the conclusion based on the kinetic analysis that IL-4 has a higher affinity for GM3 (K(d) = 5 nM) than for GM1 (K(d) = 0.28 microM).     

Determination of the penicillin acylase activity of E. coli cultures using a method of gas-liquid chromatography]

Penicillinacylase activity was determined in E. coli by the product of benzylpenicillin destruction, i.e. phenylacetic acid formed under the effect of the enzyme. The determination was performed on a chromatograph. The immobile phase consisted of 10 per cent of ethylenglycol edipate on chromosorb A, modified with 2 per cent H3PO4. Nitrogen was used as the gaseous carrier. The method is rapid and handy for mass testing of the cultures with a purpose of detecting penicillinacylase-producing strains. It provided reliable determination of penicillinacylase in the cultures producing simultaneously beta-lactamase, another penicillin-destroying enzyme.