Superoxide dismutase, glutathione peroxidase, catalase, and lipid peroxidation in the major organs of the aging rats

Glutathione peroxidase (GSh-Px), superoxide dismutase (SOD), catalase (CAT) activities and malon-dialdehyde (MDA) content were determined in heart, liver, kidney and brain of rats. Two different age groups (4 months; 24 months) were considered. GSH-Px and SOD activities decrease significantly for the aged liver and kidney. During aging, the activity of catalase increase in cardiac muscle and, in contrast, decrease in other organs. Lipids peroxidation, expressed in term of MDA formation, decrease in all the organs of the aged rats. The results indicate that: 1) the liver and kidney antioxidative defense decrease with age; 2) the enzymatic activities evolve in a different manner for different enzymes and organs. Furthermore, the results suggest that there is not any correlation between the SOD, CAT, and GSH-Px activities and the peroxidative status of the organs; thus, the age-related increase in the MDA content proposed as a criterion of aging process should be considered with caution.     

Anti-idiotypic monoclonal antibody to a T-cell chronic lymphatic leukemia

Summary A murine anti-idiotypic monoclonal antibody (mAb), F1, (IgG_2a) was produced against the variable part of the T-cell receptor for antigen (T_i, /) on the tumor cells of a patient with T-cell chronic lymphatic leukemia (CD3⁺, 8⁺, 4^–). The molecular weight of the protein reactive with mAb F1, comodulation and coprecipitation with anti-CD3 antibody, and the restricted tumor-cell reactivity strongly support the anti-idiotypic nature of mAb F1. MAb F1 also stained 4% of peripheral blood lymphocytes of healthy donors. MAb F1 did not stimulate the tumor cells to DNA synthesis, but stimulated a fraction of the normal peripheral blood lymphocytes, mAb F1 did not mediate antibody-dependent cellular cytotoxicity or complement lysis to any significant degree in vitro. Three infusions of 1–10 mg anti-idiotypic mAb were given over a period of 4 weeks. The plasma half-life for mAb F1 was 3 h in the first 2 h after infusion and 44 h from 2 h to 120 h after infusion. After each treatment a rapid decrease of circulating tumor cells was seen. During the observation period an 80% reduction of the total circulating tumor cells was noted. After the second infusion, IgM and IgG antimouse antibodies were detected. Side-effects from therapy were fever, chills, nausea, vomiting, diarrhea, tachycardia, increase in systolic blood pressure and shortness of breath. Thus, in T-cell malignancies a major reduction of circulating tumor cells can be accomplished by low doses of anti-idiotypic mAb. Anti-idiotypic mAb might be a therapeutic agent of significant importance.     

Selenium concentrations in the human thyroid gland

Recently, we found that prediagnostic serum selenium concentration was significantly lower for cases developing thyroid cancer (n=43) than for controls. We assumed that redistribution of serum selenium into the affected tissue took place in the prediagnostic period. The present study was carried out to determine the physiological concentration of selenium in the thyroid, since very few data are available in the literature. The concentrations of selenium in the thyroid (n=45) and liver samples from Norwegians who had died because of acute illness or accidents were determined by hydride generation atomic absorption spectrometry. The mean selenium concentration was found to be 0.72±0.44 μg/g in the thyroid and 0.45±0.11 μg/g in the liver tissue. The surprisingly high concentration of selenium in apparently normal thyroids indicates that selenium has important functions in this organ. The remarkably broad range, together with the observation that no significant correlation exists between thyroid and liver concentrations, suggest that factors other than the selenium status are important determinants for the selenium concentration in the thyroid gland. This observation is consistent with our hypothesis that in carcinogenesis, prediagnostic processes influence the serum-/thyroid-ratio of selenium.     

Freeze-fracture study of rat liver peroxisomes: evidence for an induction of intramembrane particles by agents stimulating peroxisomal proliferation

The membrane ultrastructure of isolated rat liver peroxisomes has been observed by rapid freezing and freeze-fracture techniques. Unidirectional and rotary shadowing allows a clear visualization of the intramembrane particles (IMPs) on both the protoplasmic fracture (PF) leaflet and the endoplasmic fracture (EF) leaflet and reveals an asymmetric distribution of IMPs. Both fracture faces were uniformly studded by IMPs, and the frequency was about seven times higher on the P face (2322 per 1.0 micron2) than on the E face (322 per 1.0 micron2). Administration of the peroxisomal proliferator clofibrate (ethyl-p-chlorophenoxyisobutyrate) induced a marked increase in the frequency of IMPs on both the P face (2.2-fold) and the E face (1.7-fold). The average size decreased (P less than 0.001) from 45.7 +/- 16.5 nm2 to 35.2 +/- 10.8 nm2 on the P face. A similar increase in the frequency of IMPs was observed on the P face (1.8-fold) and the E face (1.8-fold) of peroxisomes from rats fed a semisynthetic diet containing 20% (w/w) of partially hydrogenated fish oil. The average size increased (P less than 0.001) from 36.6 +/- 19.7 to 50.0 +/- 23.5 nm2 on the E face. This study demonstrates alterations both in frequency and size distribution of IMPs in liver peroxisomal membranes on exposure of rats to agents known to induce peroxisomal proliferation. The increase in frequency of IMPs was as expected from the observed increase in one of the major integral membrane polypeptides, with apparent molecular mass of 69 (or 70) kDa, in proliferating rat liver peroxisomes.     

Molecular evolution of pteridophytes and their relationship to seed plants: Evidence from complete 18S rRNA gene sequences

Complete 18S ribosomal RNA sequence data from representatives of all extant pteridophyte lineages together with RNA sequences from different seed plants were used to infer a molecular phylogeny of vascular plants that included all major land plant lineages. The molecular data indicate that lycopsids are monophyletic and are the earliest diverging group within the vascular land plants, whereasPsilotum nudum is more closely related to the seed plants than to other pteridophyte lineages. The phylogenetic trees based on maximum likelihood, parsimony and distance analyses show substantial agreement with the evolutionary relationships of land plants as interpreted from the fossil record.     

Rapid reactions of spruce cells to elicitors released from the ectomycorrhizal fungus Hebeloma crustuliniforme, and inactivation of these elicitors by extracellular spruce cell enzymes

Elicitors released from hyphae or cell walls of the ectomycorrhizal fungus Hebeloma crustuliniforme (Bull. ex Fries.) Quél. induced in suspension-cultured cells of Picea abies (L.) Karst. a set of fast reactions: (i) an immediate efflux of Cl^– into the medium, followed by a K⁺ efflux; (ii) an influx of Ca²⁺ (measured as accumulation of ⁴⁵Ca²⁺ in the cells); (iii) a phosphorylation of a 63-kDa protein and dephosphorylation of a 65-kDa protein (detectable by 4 min after elicitor application); (iv) an alkalinization of the medium, and (v) a transient synthesis of H₂O₂. The removal of extracellular Ca²⁺ by EGTA delayed the elicitor-induced alkalinization. A further reduction of this response could be achieved by TMB-8 an inhibitor of Ca²⁺ release from intracellular stores. Moreover, the inhibition of protein kinase activity by staurosporine prevented the extracellular alkalinization completely. However, the effectiveness of the elicitors in inducing the extracellular alkalinization was strongly impaired by constitutively secreted enzymes of spruce cells which cleaved the elicitors to inactive fragments. It is suggested that in ectomycorrhizae the efficacy of elicitors released from fungal cell walls is controlled by apoplastic enzymes of the host; the plant itself is able to reduce the activity of fungal elicitors on their way through the plant cell wall. But those elicitors which finally reach the plasma membrane of host cells induce reactions that are similar to the early defense reactions in plant-pathogen interactions.Abbreviations DW dry weight - FW fresh weight - TMB-8 3,4,5 trimethoxybenzoic acid 8-(diethylamino)-octyl ester We thank Prof. M. Zenk (Universität München, Germany) for providing spruce cell cultures, and Dr. I. Kottke (Universität Tübingen, Germany) for isolates of Hebeloma crustuliniforme Tü 704. We are also thankful to Dr. W. Mayer (Universität Tübingen) for valuble discussions. This work was supported by Deutsche Forschungsgemeinschaft. B. Zitterell-Haid was financed by Graduiertenkolleg Interaktion in Waldökosystemen (supported by Deutsche Forschungsgemeinschaft) and G. Hebe by a scholarship of the Landesgraduiertenförderungsgesetz.     

Does the energy equivalence rule apply to intertidal macrobenthic communities?

Energy equivalence assumes equal contribution of large and small species to production and energy flow in communities. As in a double logarithmic plot, physiological rates decline with body weight by –0.25, log biomass should increase by 0.25 and log abundance decline by –0.75 with log species weight, when this concept is valid. This was tested with annual data sets of the macrobenthos of 4 intertidal sites in the German Wadden Sea (Königshafen) and 3 sites in a south Portuguese lagoon (Ria Formosa). Only abundance data from two of these sites displayed significantly negative slopes with mean body size of the species. Biomass and secondary production data were significantly positively correlated with mean body size for all Ria Formosa sites and also for the biomass of a mussel bed in Königshafen. However, high variation in body size of the individuals of a species limits interpretation of these plots.It is preferable to test this concept by body weight classes regardless of its species composition. At Königshafen, biomass and production displayed two distinct peaks. One peak at small body size was caused by browsing species. The other peak at larger body size was caused by animals which potentially extract their food from the water column. This bimodality was only vaguely reflected at one station in the Ria Formosa, possibly because of a dominance of detritus feeding species. In a normalized form (log biomass or production / width of size classvs. log size class), these spectra imply a dominance of small individuals in biomass and production at all sites (except for a mussel bank at Königshafen). This is interpreted as a consequence of permanent disturbances.     

Oxidatively Modified Plasma Phospholipids Containing Reactive Carbonyl Functions Measured by HPLC: Evidence for Phosphatidylcholine-Bound Aldehydes in Plasma of Burn Patients

A HPLC method has been developed to measure phosphatidylcholine (PC) containing reactive carbonyl functions in the sn-acyl residue in order to study processes in which such reactive carbonyls can be formed due to e.g. oxidative fragmentation. The method has been applied to determine PC-bound carbonyls as 2, 4-dinitrophenylhydrazones (DNPH) in plasma of burn patients. Plasma from healthy volunteers served as controls. Additionally, in vitro oxidation experiments (A: plasma, buffer diluted; B: plasma + iron-EDTA complex and C: plasma + iron-EDTA complex + H₂O₂) have been performed to obtain and to identify 2, 4-dinitrophenylhydrazine derivatizable carbonyl functions in plasma PC. Both, the PC-aldehydes and PC-aldehyde DNPH derivatives were cleavable with phospholipase C. Quantification was based on thin-layer chromatography purified soybean phosphatidylcholine, which was identically oxidized and derivatized as the plasma lipids in vitro.