Activities of antioxidant enzymes of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> plants during cold hardening to hypothermia

Changes in activities of the enzymes performing direct antioxidant functions were studied in 7–8-week-old plants Arabidopsis thaliana Heinh (L.) of Columbia (Col-0) ecotype. It was found that 5-day cold hardening at 2°C increased plant cold resistance to the subsequent stronger cooling. Under these conditions, the marked changes occurred in activities of superoxide dismutase and III type (guaiacol) peroxidses but not in that of catalase. The total peroxidase activity exceeded the catalase activity before cold hardening. Therefore, peroxidases are able to decompose more H₂O₂ than catalases and appear to make the dominant contribution to the protection from the cold damage.     

Efficiency of KrCl excilamp (222 nm) for inactivation of bacteria in suspension

Aims: To examine the killing efficiency of UV KrCl excilamp against Gram‐positive and Gram‐negative bacteria. Methods and Results: Vegetative cells of Bacillus cereus, Bacillus subtilis, Escherichia coli O157:H7, Staphylococcus aureus and Streptococcus pyogenes at initial populations from 10² to 10⁷ colony‐forming units (CFU) ml^?1 were treated by KrCl excilamp in sterile Ringer’s solution with and without H₂O₂. The number of viable cells was determined using spread plating techniques and nutrient agar method with subsequent incubation at 28°C or 37°C for 24 h. At estimated populations of 10²–10⁵ CFU ml^?1E. coli O157:H7 and Staph. aureus were the most sensitive and showed 100% disinfection within 15 s (29·2 mJ cm^?2). Bacillus subtilis was more sensitive to UV treatment than B. cereus. The UV/H₂O₂ inactivation rate coefficients within this population range were two times higher than those observed for UV treatment alone. No effect of H₂O₂ was observed at 10⁷ CFU ml^?1 for Bacillus sp. and Strep. pyogenes. Conclusions: The narrow‐band UV radiation at 222 nm was effective in the rapid disinfection of bacteria in aqueous suspensions. Significance and Impact of the Study: KrCl excilamps represent UV sources which can be applied for disinfection of drinking water in advanced oxidation processes.     

The crystal structure of a bacterial Sufu-like protein defines a novel group of bacterial proteins that are similar to the N-terminal domain of human Sufu

Sufu (Suppressor of Fused), a two‐domain protein, plays a critical role in regulating Hedgehog signaling and is conserved from flies to humans. A few bacterial Sufu‐like proteins have previously been identified based on sequence similarity to the N‐terminal domain of eukaryotic Sufu proteins, but none have been structurally or biochemically characterized and their function in bacteria is unknown. We have determined the crystal structure of a more distantly related Sufu‐like homolog, NGO1391 from Neisseria gonorrhoeae, at 1.4 Å resolution, which provides the first biophysical characterization of a bacterial Sufu‐like protein. The structure revealed a striking similarity to the N‐terminal domain of human Sufu (r.m.s.d. of 2.6 Å over 93% of the NGO1391 protein), despite an extremely low sequence identity of ～15%. Subsequent sequence analysis revealed that NGO1391 defines a new subset of smaller, Sufu‐like proteins that are present in ～200 bacterial species and has resulted in expansion of the SUFU (PF05076) family in Pfam.     

Exclusion of immune proteasomes from mouse ascitic carcinoma Krebs-II cells

Pools of 26S and 20S proteasomes were studied in the spleen, liver, lung, and ascitic carcinoma Krebs-II of mouse. Western blotting demonstrated that the pool of 26S proteasomes in ascitic carcinoma Krebs-II was twice that in control lung cells and did not significantly differ by total 26S proteasome quantities from the spleen and liver. At the same time, the level of immune subunit LMP7 was 12 times lower in it compared to lung proteasomes and 4–5 times lower compared to spleen and liver proteasomes. Immune subunit LMP2 was undetectable by this technique in the ascitic carcinoma in contrast to the lung, spleen, and liver. All immune subunits in the studied organs and ascitic carcinoma Krebs-II are components of 26S but not 20S proteasomes.     

The Structure of a Conserved Region of Porcine Genome,Represented in Human Genome by Chromosome 17

Radiation mapping of nine genes (H3F3B, HLR1, MYL4,STAT5B, THRA1, TOP2A, MCP1, NF1, and MPO) to porcine chromosome 12 was carried out. Also, subchromosomal location of the NF1 gene along with the two loci containing the DNA sequences homologous to the DNA of the two human BAC clones was determined. The NF1 position was ascertained via microdissection of chromosome 12 with subsequent PCR amplification of the gene fragment with specific primers. BAC clones were mapped using FISH. Comparative analysis of the gene order in porcine chromosome 12 and in the homologous human chromosome 17 was performed. It was demonstrated that the gene orders in these chromosomes differed relative to the position of the MPO gene.