Differential response of antioxidant enzymes in leaves of necrotic wheat hybrids and their parents

The leaves of necrotic hybrid of wheat ( Triticum aestivum L.) exhibited high superoxide content associated with increased lipid peroxidation and membrane damage in earlier studies (Khanna-Chopra et al. 1998, Biochem Biophys Res Commun 248: 712–715; Dalal and Khanna-Chopra 1999, Biochem Biophys Res Commun 262: 109–112). In the present study, we investigated the activities of the antioxidant enzymes in the leaves of necrotic wheat hybrids, Kalyansona×C306 (K×C) and WL711×C306 (WL×C) and their parents at different developmental stages. The K×C hybrid exhibited more severe necrosis than WL×C. In K×C, superoxide dismutase (SOD) activity showed no increase over the parents, while WL×C showed an early increase, but it was possibly insufficient to scavenge increased superoxide. Activities of guaiacol peroxidase, ascorbate peroxidase and glutathione reductase were enhanced, while catalase exhibited a decrease in activity, with the appearance of visible necrosis in both the hybrids. The isozyme profile of the antioxidant enzymes was similar in the hybrids and their parents. One existing isoform of guaiacol peroxidase showed an early appearance in the hybrid and increased in intensity with the progression of necrosis. The results reveal a differential response of antioxidant enzymes in necrotic wheat hybrids as compared to their parents. The response differed in magnitude at developmental stages of the leaves, which might be related to the intensity of necrosis expressed by the hybrids.     

Subject Index to Volume 24

Subject Index

Subject Index to Volume 24     

Renal vascular resistance in glomerular diseases--correlation of resistance index with biopsy findings

Duplex Doppler sonography has been recognized as a noninvasive method to evaluate hemodynamic features of renal blood in renal and intrarenal arteries in patients with various renal diseases. The significance of duplex Doppler sonography in the evaluation of renal vascular resistance in glomerular diseases has not yet been clearly determined. The aim of the present study was to evaluate renal vascular resistance in patients with glomerular diseases by measuring intrarenal arterial resistance (RI) and to correlate RI with renal functional tests and other clinical and laboratory data. The Doppler parameters were also correlated with histopathological findings in the kidney which underwent the percutaneous biopsy. Duplex Doppler sonography was used to measure RIs in intrarenal arteries in 50 patients with glomerular diseases and 60 age-matched control subjects. The renal vascular resistance index (RI) was determined by the use of Doppler sonography. The mean RI in 50 patients with glomerular diseases was 0.68 +/- 0.09, which was statistically significantly higher than in 60 control subjects (the mean RI was 0.596 +/- 0.035). In a group of patients with membranoproliferative glomerulonephritis the mean RI was 0.817 +/- 0.624 which was statistically significantly higher than in other groups of glomerulonephritis. The renal vascular (resistance) RI significantly correlated with serum creatinine, creatinine clearance and beta2 microglobulin. Qualitative duplex sonography measure of renal arterial resistance-resistive index does not appear to be reliable in distinguishing different types of glomerulonephritis.     

Separation of fluorescence signals from Ca2+ and NADH during cardioplegic arrest and cardiac ischemia

Determinations of intracellular [Ca(2+)](i) during ischemia using fluorescent indicators are hampered by overlapping cellular autofluorescence (AF), which largely depends on NADH. If Ca(2+) is to be determined under different kinds of ischemia, signal separation merits special attention. We used triple wavelength excitation fluorescence to separate autofluorescence from [Ca(2+)]-dependent fura-2 fluorescence. Excitation at 360 nm served as third, Ca(2+)-insensitive wavelength. Using an appropriate evaluation procedure, we separated Ca(2+)-dependent signals from autofluorescence which is semiquantitatively associated with NADH, an indicator of the cellular redox state. We compared changes of [Ca(2+)](i) in isolated hearts during ischemia following cardioplegic arrest with those after transient stop of nutritive perfusion. We observed [Ca(2+)] transients in spontaneously beating hearts, persisting during ischemic episodes, and an increase of mean [Ca(2+)](i). In contrast, cardioplegic arrest stopped periodical [Ca(2+)](i) transients and heart beats simultaneously. [Ca(2+)](i) remained at diastolic values, tended to decrease during the first minutes of cardioplegic arrest and then increased slowly. Autofluorescence increased under both conditions. During ischemia, this increase was faster than in cardioplegia experiments. It started after the last heart beat despite persisting perfusion. Our measurements demonstrate that rhythmical heart beat is essential for sufficient perfusion. Reduced [Ca(2+)](i) under cardioplegic arrest may influence metabolism.     

Targeted mutagenesis of the murine IRP1 and IRP2 genes reveals context-dependent RNA processing differences in vivo

We report the targeted mutagenesis of the murine iron regulatory protein (IRP)-1 and IRP2 genes, respectively, with a classical gene trap construct. Insertion of the targeting cassette into the second intron of either gene by homologous recombination interrupts their open reading frames near the N termini. Mice that are homozygous for the correctly modified IRP1 or IRP2 alleles, respectively, display a strong reduction (90%, IRP1(-/-)) or nondetectable levels (IRP2(-/-)) of the targeted proteins. Interestingly, the pre-mRNAs transcribed from the identical targeting cassettes are processed differently within the two different contexts. Detailed analysis of the respective products identifies the choice of alternative splice and 3' end processing sites in the same tissues in vivo. We discuss the implications for the understanding of RNA processing and for targeting strategies for functional genomics in the mouse.     

Disseminated lethal Encephalitozoon cuniculi (genotype III) infections in cotton-top tamarins (Oedipomidas oedipus)--a case report

For the first time, Encephalitozoon (E.) cuniculi genotype III ('dog strain') was verified in two cotton-top tamarins (Oedipomidas oedipus) by light microscopy, immunohistochemistry, electron microscopy, PCR and sequencing. The animals had a disseminated lethal infection with this protist. In earlier reports, genotype III had been found only in domestic dogs, man, emperor tamarins (Saguinus imperator) and golden lion tamarins (Leontopithecus rosalia). This investigation establishes now that the 'dog strain' can occur in cotton-top tamarins too. This is further evidence for the zoonotic potential of E. cuniculi. Furthermore, free E. cuniculi spores were identified also in blood vessels of several tissues. These findings indicate that during a disseminated infection E. cuniculi spores can occur in peripheral blood, too. We propose that blood should also be included in the investigations for the detection of microsporidia, so that a possible disseminated course of an infection can be detected.     

Plasmid condensation induced by cationic compounds: hydrophilic polylysine and amphiphilic cationic lipid

The construction of an efficient carrier for genetic material is a major research objective that needs to be achieved before gene therapy can become a viable pharmacological approach. Artificial aggregates containing nucleic acids are one of the options for the systemic delivery of genetic information. The diversity of functions the aggregate is expected to fulfill necessitates its complex architecture. In order to obtain a complex supramolecular aggregate, formed from elements that are themselves complex molecules, appropriate procedures based on the detailed understanding of processes at the molecular level are required. In this study, we investigated how the various properties of cationic compounds affect nucleic acid condensation. The combination of two condensing agents, differing in their affinity towards water, when mixed with plasmids, resulted in aggregates which are resistant to enzymatic digestion and which form particles with well-defined size distributions. Such uniform and well-defined complexes may subsequently be further modified in order to obtain a fully functional genetic material carrier.