The effect of oral immuno-stimulation in juvenile carp (Cyprinus carpio L.)

The effect of a 2-week period of oral immuno-stimulation from the age of 2 or 6 weeks post-fertilisation (wpf; before and after reaching the ability to produce antibodies) onwards was investigated on various immune functions of the common carp, Cyprinus carpio. The immuno-stimulants Aeromonas salmonicida lipopolysaccharide, Yeast DNA (containing unmethylated CpG motifs) or high-M alginate (an extract of algae containing poly-mannuronic acid) were used. The effect of this treatment was studied on the kinetics of B cells in head kidney and peripheral blood leucocytes using flow cytometry, on the total plasma IgM level using ELISA, on cytokine and inducible nitric oxide synthase (iNOS) expression in the intestine, and acute phase protein expression in the liver, using real time quantitative PCR, and on exposure to Vibrio anguillarum. Oral administration of immuno-stimulants from 6 wpf resulted in decreased WCI12(+) (B) cell percentages in PBL (only after administration of LPS) and head kidney (all test groups), and a decreased total IgM level in plasma, suggesting that suppressive effects are strongly indicative of oral or juvenile tolerance. After administration from 2 wpf, the effects on WCI12(+) (B) cell percentages were less pronounced: the group fed with Yeast DNA showed higher percentages compared to the control group at 6 wpf, but lower percentages at 8 wpf. No changes were observed in the cytokine or iNOS expression levels in the intestine or acute phase protein expression in the liver. A challenge with V. anguillarum resulted in an initially higher cumulative mortality in the group fed with LPS, but lower mortality in the groups fed with Yeast DNA or high-M alginate compared to the control group, providing a provisional warning especially for the use of pathogen-derived immuno-stimulants, such as A. salmonicida LPS, in larval and juvenile fish.

Application of DNA from mushroom Pleurotus ostreatus for cancer biotherapy: a pilot study

AIM

In present work, the attempt to study immunomodulatory activity and biotherapeutical potential of DNA isolated from the fruit body of P. ostreatus was made.

METHODS

The efficacy of biotherapeutic application of mushroom DNA was evaluated on the BALB/c mice with subcutaneously transplanted Ehrlich carcinoma. The effect of Pleurotus ostreatus DNA on NK activity was studied in vitro using nonspecific cytotoxicity assay.

RESULTS

Application of mushroom DNA resulted in augmentation of NK cytotoxic activity in vitro and significant increase of the life span of mice with solid Ehrlich carcinoma.

CONCLUSION

The observed effects of P. ostreatus DNA administration can be probably explained by the presence of immunostimulatory unmethylated CpG motifs in DNA.

Transformation of yeast using calcium alginate microbeads with surface-immobilized chromosomal DNA

Yeast artificial chromosomes (YACs) are useful cloning vectors that have the capacity to carry large DNA inserts. The largest barrier to using such large DNA molecules in transformation experiments has been their physical instability in solution. We developed a new method of transforming yeast using chromosome-sized DNA. The method uses calcium alginate microbeads to immobilize high-density yeast chromosomal DNA. Chromosomal DNA immobilized on microbeads is physically stabilized compared with naked chromosomal DNA. The microbead-mediated transformation performed well, not only with respect to the transformation frequency with large DNA molecules (>100 kb) but also in successful transformation using split chromosome DNA that exceeded 450 kb.

High frequency gene transfer by microprojectile bombardment of intact conidia from the entomopathogenic fungus Paecilomyces fumosoroseus

Two different methods, (i) PEG and (ii) biolistic, were employed to transform protoplasts and conidia of Paecilomyces fumosoroseus using hygromycin resistance as selectable marker. Transformation frequencies varied from 1.9 to 2.5 transformants microgram-1 of DNA by the PEG method, and from 33 to 153 transformants microgram-1 of DNA by the biolistic procedure.

Interstitial telomeres are hotspots for illegitimate recombination with DNA molecules injected into the macronucleus of Paramecium primaurelia

DNA molecules injected into the macronucleus of Paramecium primaurelia replicate either as free linear telomerized or chromosome integrated molecules. In the present study we show that when a 1.77 kb BamHI DNA fragment harbouring the his3 gene of Saccharomyces cerevisiae was microinjected into the macronucleus, a fraction of the molecules are integrated into the chromosome via an illegitimate recombination process. The injected molecules were mostly inserted at their extremities at multiple points in the genome by replacing the Paramecium sequences. However, insertion sites were not totally at random. Roughly 30% of the molecules were integrated next to or in telomeric repeats. These telomeric repeats were not at the extremities of chromosomes but occupy an internal or interstitial position. We argue that such sites are hotspots for integration as the probability of random insertion near or in an interstitial telomeric site, of which there are 25-60 in a macronucleus is between 5 x 10(-4) and 3 x 10(-5).