Apoptosis,cytokine and chemokine induction by non-structural 1 (NS1) proteins encoded by different influenza subtypes

Background

Influenza pandemic remains a serious threat to human health. Viruses of avian origin, H5N1, H7N7 and H9N2, have repeatedly crossed the species barrier to infect humans. Recently, a novel strain originated from swine has evolved to a pandemic. This study aims at improving our understanding on the pathogenic mechanism of influenza viruses, in particular the role of non-structural (NS1) protein in inducing pro-inflammatory and apoptotic responses.

Methods

Human lung epithelial cells (NCI-H292) was used as an in-vitro model to study cytokine/chemokine production and apoptosis induced by transfection of NS1 mRNA encoded by seven infleunza subtypes (seasonal and pandemic H1, H2, H3, H5, H7, and H9), respectively.

Results

The results showed that CXCL-10/IP10 was most prominently induced (> 1000 folds) and IL-6 was slightly induced (< 10 folds) by all subtypes. A subtype-dependent pattern was observed for CCL-2/MCP-1, CCL3/MIP-1α, CCL-5/RANTES and CXCL-9/MIG; where induction by H5N1 was much higher than all other subtypes examined. All subtypes induced a similar temporal profile of apoptosis following transfection. The level of apoptosis induced by H5N1 was remarkably higher than all others. The cytokine/chemokine and apoptosis inducing ability of the 2009 pandemic H1N1 was similar to previous seasonal strains.

Conclusions

In conclusion, the NS1 protein encoded by H5N1 carries a remarkably different property as compared to other avian and human subtypes, and is one of the keys to its high pathogenicity. NCI-H292 cells system proves to be a good in-vitro model to delineate the property of NS1 proteins.

     

The Sexual and Mating System of the Shrimp Odontonia katoi (Palaemonidae,Pontoniinae), a Symbiotic Guest of the Ascidian Polycarpa aurata in the Coral Triangle

Theory predicts that monogamy is adaptive in symbiotic crustaceans inhabiting relatively small and morphologically simple hosts in tropical environments where predation risk away from hosts is high. We tested this prediction in the shrimp Odontonia katoi, which inhabits the atrial chamber of the ascidian Polycarpa aurata in the Coral Triangle. Preliminary observations in O. katoi indicated that males were smaller than females, which is suggestive of sex change (protandry) in some symbiotic organisms. Thus, we first investigated the sexual system of O. katoi to determine if this shrimp was sequentially hermaphroditic. Morphological identification and size frequency distributions indicated that the population comprised males that, on average, were smaller than females. Gonad dissections demonstrated the absence of transitional individuals. Thus, O. katoi is a gonochoric species with reverse sexual dimorphism. The population distribution of O. katoi in its ascidian host did not differ significantly from a random distribution and shrimps inhabiting the same host individual as pairs were found with a frequency similar to that expected by chance alone. This is in contrast to that reported for other socially monogamous crustaceans in which pairs of heterosexual conspecifics are found in host individuals more frequently than expected by chance alone. Thus, the available information argues against monogamy in O. katoi. Furthermore, that a high frequency of solitary females were found brooding embryos and that the sex ratio was skewed toward females suggests that males might be roaming among hosts in search of receptive females in O. katoi. Symbiotic crustaceans can be used as a model system to understand the adaptive value of sexual and mating systems in marine invertebrates.     

Diffusion of Mn2+ ions into liposomes mediated by phosphatidate and monitored by the activation of an encapsulated enzymatic system

Summary Transbilayer diffusion of Mn²⁺ ions occurred in liposomes formed from dipalmitoyl-phosphatidylcholine or egg-yolk phosphatidylcholine and egg-yolk phosphatidate (molar ratio 21) containing DNA and DNase I within their aqueous compartments. Cation diffusion was demonstrated by the hydrolytic activity of DNase I, activated by the Mn²⁺ ions that diffused into the vesicles, and this was confirmed by light scattering. Phosphatidate, a cone-shaped lipid which has been synthesized under simulated prebiotic conditions, was necessary for cation diffusion across the liposome membranes. Such liposomes represent a simple precellular system that interchanges cations with the surroundings and provides a microenvironment for enzymatic reactions, as evidenced by the hydrolysis of DNA by DNase I inside these closed lipid compartments.     

Neurotoxic,cytotoxic, apoptotic and antiproliferative effects of some marine algae extracts on the NA2B cell line

Oxidative stress contributes to cancer pathologies and to apoptosis. Marine algae exhibit cytotoxic, antiproliferative and apoptotic effects; their metabolites have been used to treat many types of cancer. We investigated in culture extracts of Petalonia fascia, Jania longifurca and Halimeda tuna to determine their effects on mouse neuroblastoma cell line, NA2B. NA2B cells were treated with algae extracts, and the survival and proliferation of NA2B cells were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The effects of algae extracts on oxidative stress in NA2B cells also were investigated using nitric oxide synthase (NOS) immunocytochemistry and apoptosis was assessed using terminal deoxynucleotidyl transferase dUTP nick end labeling. We observed significant neurite inhibition with moderate damage by the neurotoxicity-screening test (NST) at IC₅₀ dilutions of the extracts. MTT demonstrated that J. longifurca extracts were more toxic than P. fascia and H. tuna extracts. We found an increase of endothelial and inducible NOS immunostaining for oxidative stress and TUNEL analysis revealed increased apoptosis after application of extract. Our findings suggest that the algae we tested may have potential use for treatment of cancer.     

Regulators of complement activity mediate inhibitory mechanisms through a common C3b‐binding mode

Regulators of complement activation (RCA) inhibit complement‐induced immune responses on healthy host tissues. We present crystal structures of human RCA (MCP, DAF, and CR1) and a smallpox virus homolog (SPICE) bound to complement component C3b. Our structural data reveal that up to four consecutive homologous CCP domains (i–iv), responsible for inhibition, bind in the same orientation and extended arrangement at a shared binding platform on C3b. Large sequence variations in CCP domains explain the diverse C3b‐binding patterns, with limited or no contribution of some individual domains, while all regulators show extensive contacts with C3b for the domains at the third site. A variation of ~100° rotation around the longitudinal axis is observed for domains binding at the fourth site on C3b, without affecting the overall binding mode. The data suggest a common evolutionary origin for both inhibitory mechanisms, called decay acceleration and cofactor activity, with variable C3b binding through domains at sites ii, iii, and iv, and provide a framework for understanding RCA disease‐related mutations and immune evasion.     

Production and characterization of polyclonal and monoclonal antibodies against Aflatoxin B1 oxime-BSA in an enzyme-linked immunosorbent assay

From a single aflatoxin B₁ oxime — bovine serum albumin conjugate, polyclonal and monoclonal antibody preparations were produced. The four rabbit polyclonal antisera were specific for aflatoxin Bi in a microtitration plate enzyme — linked immunosorbent assay. The monoclonal antibodies showed a wide range of differing specificities, recognizing, for example, aflatoxins B₁, B₂, G₁ and G₂; B₁ and B₂; B₁ and G₁; and G₁ alone. No antibody preparations reacted with aflatoxin M₁. The significance of these results to the strategy of anti-aflatoxin antibody production for use in quantitative enzyme immunoassays is discussed.     

Lernaeopoda tenuis n. sp. andPseudolernaeopoda caudocapta n. g., n. sp. (Copepoda,Lernaeopodidae) parasitic onTriakis maculata (Kner & Steindachner) from the Chilean coast,South Pacific

Summary One new genus and two new species of the Lernaeopodidae (Copepoda: Siphonostomatoida), parasitic onTriakis maculata off the coast of Chile, are described and illustrated. The new genus,Pseudolernaeopoda, parasitizes the cloaca of its host. Its type-species,P. caudocapta, can be distinguished fromLernaeopoda by the absence of modified uropods. A new species ofLernaeopoda, L. tenuis, was found on the gills of the same host. In absence of the male, the generic affinities of this species must be considered only tentative. ac]19850409     

Softwood biodegradation by an ascomycete Chrysonilia sitophila (TFB 27441 strain)

Biodegradation of softwood ( Pinus radiata ) by the ascomycete Chrysonilia sitophila was dependent on the nitrogen and glucose concentrations in the culture medium. Optimization studies of the delignification process, in which the nitrogen (0–50mmol/l NH⁺₄) and glucose (0–2%) concentrations were varied, showed a maximal value of 17·8% for sawdust degradation in cultures containing 10 mmol/l NH₄⁺and 1·0% glucose. Solubility of the decayed sawdust in 1% NaOH at maximal delignification conditions showed a threefold increase and changes in the thermogravimetric pattern were also observed. Biodegraded wood chips showed significant decreases of the 280 and 310 nm characteristic lignin bands in the u.v. reflectance spectra.