Cortical Phase-Amplitude Coupling in a Progressive Model of Parkinsonism in Nonhuman Primates.

Parkinson's disease is associated with abnormal oscillatory electrical activities of neurons and neuronal ensembles throughout the basal ganglia-thalamocortical network. It has recently been documented in patients with advanced parkinsonism that the amplitude of gamma-band oscillations (50-200 Hz) in electrocorticogram recordings from the primary motor cortex is abnormally coupled to the phase of beta band oscillations within the same signals. It is not known when in the course of the disease the abnormal phase-amplitude coupling (PAC) arises, and whether it is influenced by arousal or prior exposure to dopaminergic medications. To address these issues, we analyzed the relationship between the severity of parkinsonian motor signs and the extent of PAC in a progressive model of parkinsonism, using primates that were not exposed to levodopa prior to testing. PAC was measured in electrocorticogram signals from the primary motor cortex and the supplementary motor area in 3 monkeys that underwent weekly injections of small doses of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, rendering them progressively parkinsonian. We found that parkinsonism was associated with increased coupling between the phase of low-frequency (4-10 Hz) oscillations and the amplitude of oscillations in the high gamma band (50-150 Hz). These changes only reached significance when the animals became fully parkinsonian. The increased PAC was normalized after levodopa treatment. We also found a similar increase in PAC during sleep, even in normal animals. The identified PAC was independent of concomitant changes in spectral power in the 2.9-9.8Hz or 49.8-150.4 Hz ranges. We conclude that PAC is predominately a sign of advanced parkinsonism, and is, thus, not essential for the development of parkinsonism. However, increased PAC appears to correlate with the severity of fully developed parkinsonism.

Localisation of a carbohydrate epitope recognised by human IgE in pollen of Cupressaceae.

The objectives of the present study were: (1) to localise, at the subcellular level, the allergens in pollen of Cupressaceae species, using a monoclonal antibody (mAb 5E6) that is specific for carbohydrate epitopes of allergenic components of Cupressus arizonica pollen extract; (2) to determine whether the glycidic epitope recognised by mAb 5E6 was present in pollen of allergenic species taxonomically unrelated to Cupressaceae; and (3) to determine whether human IgE purified from monosensitive patients recognises the same epitope as mAb 5E6 in Cupressaceae pollen. Immunogold labelling of mAb 5E6 showed a high density of gold particles on the orbicules, supporting the hypothesis that they are important vectors of allergens. A high density was also found on the exine and in the cytoplasm, with the latter finding confirming that fragments of pollen ruptured under humid conditions can represent a vector. The glycidic epitope recognised by mAb 5E6 was detected in all of the species taxonomically unrelated to Cupressaceae, although with varying density. Human IgE recognised the same epitope as mAb 5E6. These findings are consistent with observations of diffuse allergenic cross-reactivity among various allergens. The in situ localisation of a common epitope recognised by both a monoclonal antibody and human IgE could be of importance in immunotherapy.

Evaluation of the fern Azolla for growth, nitrogen and phosphorus removal from wastewater.

Water fern (Azolla filiculoides Lam.) has been assessed for nitrogen and phosphorus removal in outdoor experiments comparing sewage water (S) from an experimental aquaculture plant, well water (W) and mineral growth medium Hoagland (H). The experiments were undertaken during the spring and the summer. The yield of fern biomass and nitrogenase activity was higher in H than in W and S waters. The enzyme activity had a decreasing trend with significant differences (p < 0.05) in the three waters. Peroxidase (POD) activity in April decreased with significative differences in W and S waters (p < 0.05). The electrical conductivity and the concentrations of NO3- in the three waters decreased significantly (p < 0.05). The highest removal of nitrate from the media was obtained in July. In S water, NO2- concentration decreased, while it increased in W water. PO(4)3- concentration was very low in W and S waters and decreased in H medium. The results obtained confirm the ability of the fern to grow in sewage water.

Effect of lonidamine on alpha2-macroglobulin, hemopexin and alpha1-antitrypsin in the rat testis and epididymis.

In a recent study (Leone et al., 2000) we reported that lonidamine (LND), an antispermatogenic drug, affected the concentration of selected testicular and epididymal proteins in the rat. Thus, the effect of LND on alpha2-macroglobulin (alpha2-M) and on other two acute phase proteins (APP), hemopexin (HPX) and alpha1-antitrypsin (alpha1-AT) was examined here. LND was administered orally at the dose of 100 mg/kg, the animals were killed after 24 and 48 hr and the samples were analyzed by immunoblotting. The drug did not induce any significant change of alpha2-M in the serum or testis and of HPX and alpha1-AT in the serum, testis or epididymis. Thus, the antispermatogenic action of LND was not accompanied by a significant change of these inflammatory markers, even if it did cause a decrease of alpha1-inhibitor-3, a negative APP, as previously reported (Leone et al., 2000).

Ionizing-radiation resistance in the desiccation-tolerant cyanobacterium Chroococcidiopsis.

The effect of X-ray irradiation on cell survival, induction, and repair of DNA damage was studied by using 10 Chroococcidiopsis strains isolated from desert and hypersaline environments. After exposure to 2.5 kGy, the percentages of survival for the strains ranged from 80 to 35%. In the four most resistant strains, the levels of survival were reduced by 1 or 2 orders of magnitude after irradiation with 5 kGy; viable cells were recovered after exposure to 15 kGy but not after exposure to 20 kGy. The severe DNA damage evident after exposure to 2.5 kGy was repaired within 3 h, and the severe DNA damage evident after exposure to 5 kGy was repaired within 24 h. The increase in trichloroacetic acid-precipitable radioactivity in the culture supernatant after irradiation with 2.5 kGy might have been due to cell lysis and/or an excision process involved in DNA repair. The radiation resistance of Chroococcidiopsis strains may reflect the ability of these cyanobacteria to survive prolonged desiccation through efficient repair of the DNA damage that accumulates during dehydration.

A method for DNA extraction from the desert cyanobacterium chroococcidiopsis and its application to identification of ftsZ

A method was developed for extraction of DNA from Chroococcidiopsis that overcomes obstacles posed by bacterial contamination and the presence of a thick envelope surrounding the cyanobacterial cells. The method is based on the resistance of Chroococcidiopsis to lysozyme and consists of a lysozyme treatment followed by osmotic shock that reduces the bacterial contamination by 3 orders of magnitude. Then DNase treatment is performed to eliminate DNA from the bacterial lysate. Lysis of Chroococcidiopsis cells is achieved by grinding with glass beads in the presence of hot phenol. Extracted DNA is further purified by cesium-chloride density gradient ultracentrifugation. This method permitted the first molecular approach to the study of Chroococcidiopsis, and a 570-bp fragment of the gene ftsZ was cloned and sequenced.

Age and forgetfulness: the effect of implicit priming.

Participants (i.e., perceivers) unscrambled either memory-related phrases (experimental group) or memory-neutral phrases (control group). Then perceivers read a vignette about a forgetful young, middle-aged, or old target person, after which they rated (a) the target's forgetfulness and (b) how difficult each of 12 tasks (4 low, 4 medium, and 4 high in memory load) would be for the target. High-memory-load tasks were rated as more difficult by perceivers in the experimental group than by perceivers in the control group. Thus, implicit priming of a forgetfulness schema resulted in harsher judgments about how difficult high-memory-load tasks would be for forgetful targets. However, this priming effect was no stronger for old than for young or middle-aged targets.

Age and forgetfulness: confidence in ability and attribution for memory failures.

Perceivers read a script of a forgetful young, middle-aged, or older male or female target being interviewed for a volunteer position. Afterward perceivers rated their opinion of the target's memory, confidence in the target's capability of performing tasks, and attributions for the target's memory failures. Perceivers were more confident and attributed failures more to lack of effort and attention when targets experienced episodic than semantic memory failures. Perceivers' memory opinion was less negative for older than for young and middle-aged targets, but their confidence ratings were equivalent across target age groups. Perceivers used an age-based double standard in their attribution ratings. However, double-standard evidence was not as strong as in prior studies using less evaluative contexts.

Age and forgetfulness: managing perceivers' impressions of targets' capability.

Two experiments investigated the effect of positive endorsement on perceivers' impressions of young and old female targets. In Experiment 1, 160 young adult perceivers listened to a tape of a young or old forgetful target being interviewed for a volunteer job. They read a nonelaborative or elaborative reference letter for the target either before or after listening to the tape. Perceivers who read the elaborative letter after listening to the tape rated themselves as more likely to assign tasks to both young and old targets and had a higher general capability opinion of old targets. In Experiment 2, 84 older adult perceivers read an elaborative letter and listened to one of the same taped interviews. Reading the letter after the tape resulted in higher task ratings than reading it before the tape, but letter order had no effect on general capability ratings. Results are discussed in terms of impression management.

Cytology of long-term desiccation in the desert cyanobacterium Chroococcidiopsis (Chroococcales).

Young and old cultures (up to 66 months) of two Chroococcidiopsis sp. strains isolated from the Negev desert, Israel, were examined by epifluorescence and electron microscopy. In old cultures, cell viability and autofluorescence were lower than in young cultures. An increase was seen with age in the polysaccharide content of the sheaths of nanocytes and nanocyte mother cells, and a decrease of phycobiliproteins was also seen. In the oldest cultures most of the cells were dead and in various stages of degeneration. Single living cells were scattered among the dead ones. No resting cells were formed in the oldest cultures, but many cell groups showed highly electron-dense sheaths and, in the cytoplasm, ribosomes and glycogen. These changes in cell structure may have a role in preventing water loss from the cell.

Immunochemical and immunohistochemical detection of S-100-like immunoreactivity in spinach tissues.

S-100 proteins represent a group of closely related acidic, calcium binding proteins originally isolated from the mammalian nervous system and later detected in non-neural cell types and in a wide variety of vertebrate and invertebrate species. The present study used immunochemical and immunohistochemical methods to extend the investigation of S-100 during phylogenesis to plant tissues. The presence of S-100-like immunoreactive material was detected in extracts of spinach (Spinacia oleracea L.) terminal buds and young leaves by the ELISA method and by Western blotting using different anti-S-100 rabbit antisera. Using the PAP method, serial sections of young spinach leaves treated with the same antisera exhibited an immunoreaction product that was confined to the cytoplasm and nucleus (but absent from the vacuoles) in meristematic, epidermal, and parenchymal cells. The present data enlarge the field of investigation of S-100 proteins in the search of the function(s) of S-100 in biological organisms.

Indole-3-acetic acid (IAA) production by Arthrobacter species isolated from Azolla.

Arthrobacter species, isolated from the leaf cavities and the microsporocarps of the aquatic fern species Azolla pinnata and Azolla filiculoides, produced indole-3-acetic acid (IAA) in culture when the precursor tryptophan was added to the medium. No IAA production was detected in the absence of tryptophan. Maximum IAA formation was obtained in the first 2 d of incubation. Part of the tryptophan was transformed to N alpha-acetyl-L-tryptophan.

Quantitative and qualitative DNA variations in Anabaena azollae Strasb. living in Azolla filiculoides lam.

Heterocysts and vegetative cells of the filamentous nitrogen-fixing Anabaena azollae isolated from the apex to the basal leaf cavities of Azolla filiculoides were examined by epifluorescent microscope after fluorochrome staining. Acridine orange (AO), DAPI, and chromomycin fluorochromes were used in order to evidence total DNA content and respectively, A + T and G + C bases. Measurements of fluorescence intensities were made on photographic prints by the automatic image analysis system Quantimet 970. Heterocysts contained higher amounts of DNA than did vegetative cells, and their content strongly increased in the basal leaf cavities. The heterocyst DAPI brightness was quite uniform, whereas in vegetative cells DAPI brightness increased from the apex to the basal groups. In vegetative cells from the apex to the median group, the percentage of DAPI brightness was 60-85% with respect to AO brightness, whereas in heterocysts of the same groups DAPI brightness was 40-50% with respect to AO brightness. In the basal group, brightness due to DAPI staining was comparable with those of previous group both in heterocysts and in vegetative cells, whereas chromomycin brightness increased strongly in heterocysts. These data show that heterocyst changes its DNA content and composition in the basal leaf cavities, suggesting that its lifetime is not completely over.

Purification of iron superoxide dismutase from the cyanobacterium Anabaena cylindrica Lemm. and localization of the enzyme in heterocysts by immunogold labeling.

Iron superoxide dismutase (Fe-SOD; EC 1.15.1.1) was isolated from the nitrogen-fixing cyanobacterium Anabaena cylindrica Lemm. Polyacrylamide gel electrophoresis separated the purified protein into three closely running, enzymatically active bands. The molecular weight of the enzyme was estimated by gel filtration to be about 40 kDa. Polyclonal antibodies were produced by immunization of rabbits with the isolated enzyme, and were purified on a column of protein A-Sepharose. The Fe-SOD antibody reacted with the purified Fe-SOD and also specifically recognized the protein in extracts of A. cylindrica. In the extracts, anti-Fe-SOD did not cross-react with Mn-SOD, an enzyme which belongs to an SOD class displaying high homology of primary and three-dimensional structure with respect to Fe-SOD. Iron superoxide dismutase was localized in heterocysts by immunogold labeling and transmission electron microscopy. These results are the first in-situ evidence for the presence of SOD in the cells specialized for nitrogenase activity.

Superoxide Dismutase in the Symbiont Anabaena azollae Strasb.

Superoxide dismutase was investigated in the symbiont Anabaena azollae Strasb. living in Azolla filiculoides Lam. In vegetative cells, three isoenzymatic forms of superoxide dismutase, containing manganese, iron, and the hybrid iron-manganese, respectively, were present. Hybrid superoxide dismutase, detected for the first time in cyanobacteria, was 7% of the total superoxide dismutase present in vegetative cells. All three superoxide dismutase forms increased in the Anabaena vegetative cells obtained from irradiated plants grown in winter. In heterocysts, only an iron superoxide dismutase was present, which amounted to 25% of total vegetative cell superoxide dismutase activity. Hybrid superoxide dismutase appeared in heterocysts after irradiation. In vegetative cells of Anabaena from plants grown in summer, the basal level of total superoxide dismutase increased by 60% as compared with winter, and was unaffected by irradiation. The levels of superoxide dismutase in heterocysts from control and exposed plants grown in summer were comparable to those observed in heterocysts obtained from the plants grown during winter. No direct correlation was found between nitrogenase activity and superoxide dismutase in heterocysts. The presence of cyanophycin granules, either within the heterocyst pore channel or close to the transversal septum of vegetative cells, suggested a mechanism to stop communications between vegetative cells and heterocysts.