julilili42/papers huggingface dataset:
Selection favours low hsp70 levels in chronically metal-stressed soil arthropods
2000-07-01

Abstract Thirty-eight populations of woodlice (Oniscus asellus, Porcellio scaber) and millipedes (Julus scandinavius) from 28 differently metal-polluted field sites were analysed for their 70-kDa stress protein (hsp70) level. Although ANOVA revealed significant dependence of the hsp70 level on the concentrations of water-soluble lead, cadmium and zinc and the soil pH, each of these parameters accounted for at most 18% of the intersite variability of the stress protein level only. A multivariate model based on multiple regression analysis explained more than 96% of hsp70 variance and revealed both the pollution history of a site (strong metal contamination for more than 70 years) and invertebrate species identity to act as the most important parameters. The model accounted for the observation that most of the populations from long-term polluted sites exhibited comparatively low stress protein levels in response to their own (contaminated) habitats. In contrast, isopods (O. asellus) from a control site were not able to maintain a low hsp70 level when they were exposed to either an artificial metal cocktail or soil taken from one of the contaminated field sites. They did not acclimatize to the exposure conditions within 3 months. We propose that selection of insensitive phenotypes in long-term polluted soils has taken place so as to minimize the stress protein level which, in turn, is indicative of high intracellular protein integrity. Long-term selection for a high hsp70 level to compensate for adverse metal impact was not observed, which suggests that such a strategy may trade off against other fitness consequences. In this context, insensitivity to metal stress involved increased selectivity in food choice and reduced variability in stress response. Multiple regression models showed species-specificity in those abiotic factors which determined (1) high hsp70 levels in sensitive populations as well as (2) low hsp70 levels in insensitive ones. Therefore, abiotic factors can be assigned to act as the main components of selection: lead and cadmium for J. scandinavius and O. asellus, zinc for P. scaber.
Phospholipase A secreted byLegionella pneumophiladestroys alveolar surfactant phospholipids
2000-07-01

Destruction of alveolar surfactant phospholipids by bacterial phospholipases is suggested to be a major virulence factor involved in bacterial pneumonia. Since Legionella pneumophila secretes phospholipase A, we analyzed phospholipid degradation in natural bovine surfactant by L. pneumophila. Phospholipids were reduced in amount after incubation with bacteria or culture supernatant of L. pneumophila serogroup 6. Free fatty acids and lysophosphatidylcholine were formed, the latter is known to be highly cytotoxic. Surface tension of surfactant as determined by pulsating bubble surfactometer increased significantly compared to the control. Phospholipase A activity seems to be a powerful agent of legionellae in causing lung disease.
Improved sensitivity proteomics by postharvest alkylation and radioactive labeling of proteins
2000-07-01

We describe approaches to improve the detection of proteins by postharvest alkylation and subsequent radioactive labeling with either [3H]iodoacetamide or 125I. Database protein sequence analysis suggested that cysteine is not suitable for detection of the entire proteome, but that cysteine alkylating reagents can increase the number of proteins able to be detected by iodination chemistry. Proteins were alkylated with beta-(4-hydroxyphenyl)ethyl iodoacetamide, or with 1,5-l-AEDANS (the Hudson Weber reagent). Subsequent iodination using the Iodo-Gen system was found to be most efficient. The enhanced sensitivity obtainable by using these approaches is expected to be sufficient for visualization of the lowest copy number proteins from human cells, such as from clinical samples. However, we argue that significantly improved methods of protein separation will be necessary to resolve the large number of proteins expected to be detectable with this sensitivity.
Expression of the inducible nitric oxide synthase (iNOS) in human leukocytes: responses to running exercise
2000-07-01

Our investigations revealed an increased expression of iNOS at the transcriptional and translational level in response to vigorous exercise. This reflects an inflammatory response and may contribute to an exercise-induced rise of endogenous nitric oxide production. It remains unclear if these effects serve an in-vivo immunoregulatory or cell-damaging role.
Quality Assessment of Heparin Coatings by their Binding Capacities of Coagulation and Complement Enzymes
2000-07-01

In vitro testing of blood contacting materials before clinical application is generally advisable. Four heparin coatings from different manufacturers were tested for adsorbed proteins and soluble activation markers. The surface with the highest antithrombin, thrombin, high-molecular-weight-kininogen (HMWK) and the lowest fibrinogen binding capacity (Carmeda, Medtronic) showed significantly lower levels of granulocytes and platelet activation (β-TG, PMN-elastase release). No statistically significant differences in soluble markers of the coagulation system could be detected (F1+2, TAT). Interestingly, complement activation (TCC) was significantly reduced within the group of the lowest adsorption of the complement factor C3. Our data demonstrate that there is a relation between the binding affinity of proteins (C1-inhibitor, C3-complement) and the consecutive changes in complement activation (TCC). Therefore, measuring adsorbed proteins on artificial surfaces is a suitable, sensitive and very reproducible method for assessing the thrombogenicity of biomaterials.
The ORF8 Gene Product of Agrobacterium rhizogenes TL-DNA Has Tryptophan 2-Monooxygenase Activity
2000-07-01

The open reading frame 8 (ORF8) is located on the TL-DNA of the phytopathogenic soil bacterium Agrobacterium rhizogenes strain A4. The predicted ORF8 protein has a particular structure and is possibly a natural fusion protein. The N-terminal domain shows homology to the A. rhizogenes rolB protein and may modulate the auxin responsiveness of host cells. The C terminus has up to 38% homology to tryptophan 2-monooxygenases (t2m). We show that ORF8 overexpressing plants contain a fivefold higher concentration of indole-3-acetamide (IAM) than untransformed plants. Protein extracts from seedlings and Escherichia coli overexpressing ORF8 show significantly higher turnover rates of tryptophan to IAM than negative controls. We conclude that the ORF8 gene product has tryptophan 2-monooxygenase activity.
Definition of peptide binding motifs amongst the HLA‐A*30 allelic group
2000-07-01

Abstract: HLA class I molecules present endogenously processed peptide ligands for surveillance by the T‐cell receptor. This potentially immunogenic surface of HLA and peptide is a consequence of the polymorphism found within the HLA molecule and its preference for ligand binding together with peptide conformation within the binding groove. To investigate the relation between the polymorphic differences between some closely related HLA alleles and their effect on peptide preference, transfectants were established, each containing one of four allelic variants of HLA‐A*30. Peptides from all four transfectants were eluted, and both individual ligands and peptide pools were sequenced. The data shows two distinct peptide motifs which distinguish A*3001 from the other three known A*30 variants. Differences in preferences at minor positions within the peptide sequence were noted between A*3002, A*3003 and A*3004, providing additional evidence of the implications of sequence polymorphism to HLA function.
Agonist-induced cytoplasmic volume changes in cultured rabbit parietal cells
2000-07-01

Concomitant Na + /H + and Cl − /HCO 3 − exchange activation occurs during stimulation of acid secretion in cultured rabbit parietal cells, possibly related to a necessity for volume regulation during the secretory process. We investigated whether cytoplasmic volume changes occur during secretagogue stimulation of cultured rabbit parietal cells. Cells were loaded with the fluorescent dye calcein, and the calcein concentration within a defined cytoplasmic volume was recorded by confocal microscopy. Forskolin at 10 −5 M, carbachol at 10 −4 M, and hyperosmolarity (400 mosmol) resulted in a rapid increase in the cytoplasmic dye concentration by 21 ± 6, 9 ± 4, and 23 ± 5%, respectively, indicative of cell shrinkage, followed by recovery to baseline within several minutes, indicative of regulatory volume increase (RVI). Depolarization by 5 mM barium resulted in a decrease of the cytoplasmic dye concentration by 10 ± 2%, indicative of cell swelling, with recovery within 15 min, and completely prevented forskolin- or carbachol-induced cytoplasmic shrinkage. Na + /H + exchange inhibitors slightly reduced the initial cell shrinkage and significantly slowed the RVI, whereas 100 μM bumetanide had no significant effect on either parameter. We conclude that acid secretagoguges induce a rapid loss of parietal cell cytoplasmic volume, followed by RVI, which is predominantly mediated by Na + /H + and Cl − /HCO 3 − exchange.
Genetic diversity of Plasmodium falciparum infections in one family in Lambaréné
2000-07-01

Journal Article Genetic diversity of Plasmodium falciparum infections in one family in Lambaréné Get access Michel A. Missinou, Michel A. Missinou 1Department of Parasitology, Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany2Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon Search for other works by this author on: Oxford Academic PubMed Google Scholar Oliver Dangelmaier, Oliver Dangelmaier 1Department of Parasitology, Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany2Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon Search for other works by this author on: Oxford Academic PubMed Google Scholar Jürgen F.J. Kun, Jürgen F.J. Kun ∗ 1Department of Parasitology, Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany ∗Author for conespondence: phone +49 7071 2980240, fax +49 707 1 295 189. juergen.kun@uni-tuebingen.de Search for other works by this author on: Oxford Academic PubMed Google Scholar Peter G. Kremsner Peter G. Kremsner 1Department of Parasitology, Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany2Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon Search for other works by this author on: Oxford Academic PubMed Google Scholar Transactions of The Royal Society of Tropical Medicine and Hygiene, Volume 94, Issue 4, July-August 2000, Page 376, https://doi.org/10.1016/S0035-9203(00)90109-3 Published: 01 August 2000 Article history Received: 17 January 2000 Revision received: 20 March 2000 Accepted: 11 April 2000 Published: 01 August 2000
The heterodimeric amino acid transporter 4F2hc/LAT1 is associated inXenopusoocytes with a non‐selective cation channel that is regulated by the serine/threonine kinase sgk‐1
2000-07-01

System L is the major Na(+)-independent amino acid transporter of mammalian cells. It is constituted of the type II membrane protein 4F2hc (CD98) which is covalently linked to the polytopic membrane protein LAT1 via a disulfide bridge. The transporter is known to be regulated by the mineral corticoid aldosterone in Xenopus A6 cells. To understand the regulation of the transporter, the 4F2hc/LAT1 heterodimer was functionally expressed in Xenopus laevis oocytes and its transport properties were analysed using flux measurements and the two-electrode voltage-clamp technique. Expression of 4F2hc/LAT1 resulted in a rapid increase in a Na(+)-independent neutral amino acid antiport activity and simultaneously gave rise to a cation conductance. The cation channel was non-rectifying and non-selective, conducting Li(+) > Cs(+) = Na(+) > K(+). After replacement of Na(+) by NMDG, however, the currents were suppressed almost completely. The cation channel was not inhibited by amiloride, Ba2(+), TEA, Hoe293B, flufenamic acid or substrates of the system L amino acid transporter. Significant inhibition, however, was observed in the presence of La3(+), Gd3(+) and quinidine. Channel activity was upregulated by coexpression of 4F2hc/LAT1 with the aldosterone-regulated protein kinase sgk-1. The cation conductance was sensitive to changes in the redox potential, being inhibited following incubation of the oocytes with DTE for 30 min. Mutation of either of the disulfide bridge-constituting cysteines to serine resulted in a loss of ion channel activity whereas amino acid transport was unaffected. It is concluded that the 4F2hc/LAT1 heterodimer regulates a closely associated cation channel or even constitutes a cation channel itself.
Luminescence of New 2,6- and 1,5-Naphthalene-Based PPV-TypeTrimers and Polymers
2000-07-01

A series of new soluble 2,6- and 1,5-conjugated naphthalene-based PPV-analogous trimers (1a,b−6a,b) and polymers (24, 25, 26) have been synthesized by means of Knoevenagel and Wittig reactions, combining appropriate 1,5- and 2,6-functionalized naphthylene or phenylene building blocks. The influence of cyano substituents at the vinylic double bonds of the aromatic chromophores, and of the way in which they are linked, on the absorption and photoluminescence spectra has been investigated. The electroluminescent behaviour of the new compounds has been studied in ITO/copper phthalocyanine (PcCu)/emitter (trimer or polymer)/Al devices, demonstrating the aptitude of trimeric and polymeric 1,5-naphthylenevinylenes for use in organic light-emitting diodes for the first time.
Chronic Schistosomiasis: Dendritic Cells Generated from Patients Can Overcome Antigen‐Specific T Cell Hyporesponsiveness
2000-07-01

Chronic infection with helminths is associated with down-regulated antigen-specific T cell responses. In order to determine whether schistosome-specific T cells are present, yet functionally unresponsive, or absent in the periphery of chronically infected persons, autologous granulocyte-macrophage colony-stimulating factor and dendritic cells (DC) derived from interleukin (IL)-4 were used as highly efficient antigen-presenting cells (APC). Peripheral blood mononuclear cells (PBMC) from persons harboring Schistosoma haematobium infection and hyporesponsive to parasite antigen were cocultured with autologous DC in the presence of adult worm antigen (AWA). In contrast to PBMC alone, DC-supplemented cultures responded to AWA by proliferation and by IL-4 and IL-5 production and, in some patients, by production of interferon-gamma. Thus, schistosome-specific T helper cells are present in the periphery but are functionally hyporesponsive during active infection with schistosomes. Cytokine responses representing the Th1 and (more importantly) Th2 types can be restored in vitro when DC are used as APC.
Sodium reabsorption in thick ascending limb of Henle's loop: effect of potassium channel blockade in vivo
2000-07-01

Based on previous in vitro studies, inhibition of K + recycling in thick ascending limb (TAL) is expected to lower Na + reabsorption through (i) reducing the luminal availability of K + to reload the Na + ‐2Cl − ‐K + cotransporter and (ii) diminishing the lumen positive transepithelial potential difference which drives paracellular cation transport. This issue was investigated in anaesthetized rats employing microperfusion of Henle's loop downstream from late proximal tubular site with K + ‐free artificial tubular fluid in nephrons with superficial glomeruli. The unselective K + channel blocker Cs + (5–40 m M ) dose‐dependently increased early distal tubular delivery of fluid and Na + with a maximum increase of ∼20 and 185%, respectively, indicating predominant effects on water‐impermeable TAL. The modest inhibition of Na + reabsorption in response to the 15 m M of Cs + but not the enhanced inhibition by 20 m M Cs + was prevented by luminal K + supplementation. Furthermore, pretreatment with 20 m M Cs + did not attenuate the inhibitory effect of furosemide (100 μ M ) on Na + ‐2Cl − ‐K + cotransport. Neither inhibitors of large (charybdotoxin 1 μ M ) nor low (glibenclamide 250 μ M ; U37883A 100 μ M ) conductance K + channels altered loop of Henle fluid or Na + reabsorption. The intermediate conductance K + channel blockers verapamil and quinine (100 μ M ) modestly increased early distal tubular Na + but not fluid delivery, indicating a role for this K + channel in Na + reabsorption in TAL. As observed for equieffective concentrations of Cs + (15 m M ), Na + reabsorption was preserved by K + supplementation. The results indicate that modest inhibition of K + channels lowers the luminal availability of K + and thus transcellular Na + reabsorption in TAL. More complete inhibition lowers paracellular Na + transport probably by reducing or even abolishing the lumen positive transepithelial potential difference. Under the latter conditions, transcellular Na + transport may be restored by paracellular K + backleak. British Journal of Pharmacology (2000) 130 , 1255–1262; doi: 10.1038/sj.bjp.0703429
Low-Dose Oral Clonidine as Premedication before Intraocular Surgery in Retrobulbar Anesthesia
2000-07-01

Purpose We investigated whether low-dosed oral clonidine premedication before elective intraocular surgery in retrobulbar anesthesia is effective in terms of anxiolysis, sedation, stable hemodynamics, lower intraocular pressure and perioperative endocrine stress response. Methods In a prospective, randomised, double-blind study, 44 patients scheduled for elective intraocular surgery received either 0.15 mg clonidine (n=22) or a matched placebo (n=22) orally 60 minutes before retrobulbar anesthesia. The main study parameters were sedation, anxiolysis, hemodynamics and intraocular pressure. Additionally, mediators of endocrine stress responses were measured five times, in 13 patients after clonidine and 12 after placebo. Results After clonidine 86% of the patients showed sedation and after placebo 90.9% showed no sedation (p&lt;0.01). Clonidine produced effective anxiolysis (Erlanger-Anxiety-Scale: 31.6 ± 2.6 points vs. 38.1 ± 8.5 points) before the operation (p&lt;0.01). Systolic blood pressure was significantly lower after clonidine. Effects on mean and diastolic blood pressure were small but statistically significant. Norepinephrine and cortisole plasma concentrations were significantly lower after clonidine. Intraocular pressure was significantly lower too (p&lt;0.05). No clinically relevant adverse effects were observed e.g. inappropriate sedation, hypotension (&lt;100 mmHg), bradycardia (&lt;50 bpm) or hypoxemia (SpO 2 &lt;90%). Conclusions Oral low-dose clonidine produces light sedation, significant anxiolysis and stable hemodynamics, and attenuates the endocrine response to perioperative stress. Thus, clonidine seems sufficient to increase patient comfort for intraocular surgery and might even offer clinically worthwhile benefits such as stable hemodynamics and a reduced response to perioperative stress.
Outcome at Age 4 Years in Offspring of Women With Maternal Phenylketonuria: The Maternal PKU Collaborative Study
2000-07-01

The offspring of women with untreated phenylketonuria(PKU) are at very high risk of being mentally retarded and microcephalic. Low birth weight and congenital heart disease also may occur. Whether dietary management during pregnancy improves developmental outcomes was examined in the Maternal PKU Collaborative Study, a longitudinal prospective trial started in 1984 at 78 metabolic clinics and obstetrical offices in the United States, Canada, and Germany. The 149 children whose mothers had PKU were followed to age 4 years, as were 33 children whose mothers had mild, untreated hyperphenylalaninemia and 71 children whose mothers had no metabolic disorders. The women with PKU were offered a low-phenylalanine diet intended to maintain the plasma phenylalanine concentration at 10 mg/dl or less. The McCarthy Scales of Children’s Abilities was the primary instrument used for assessment; this instrument was supplemented by the Test of Language Development– Primary, the Achenbach Child Behavior Checklist, and the Vineland Adaptive Behavior Scales. The Home Observation for Measurement of the Environment scale provided a measure of the physical features of the home and the experiences available to the child. McCarthy Scale scores dropped as the time to metabolic control increased, suggesting a dose-response relationship. Language dysfunction and abnormal perceptual performance/motor scores were especially evident. Children whose mothers achieved metabolic control after pregnancy began but within 6 weeks of birth did less well overall than those treated before conception. Language testing pointed to specific effects on expressive language and memory. In the behavioral realm, 30 percent of children received total behavior problem ratings in the clinical range, with an expected frequency of 18 percent. Few children had somatic problems, anxiety, or delinquency. Social skills seemed to develop more slowly than usual. The children whose mothers had PKU had significantly lower McCarthy Scale scores at age 4 than Bayley Scale scores at age 2 years. The best way to protect children of mothers with PKU is to ensure that women gain metabolic control before conception Maternal phenylalanine levels higher than 10 mg/dl during pregnancy clearly affect the fetus adversely. Children born to women with PKU closely resemble those whose mothers consume large amounts of alcohol. It is possible that, after birth, the home environment could moderate the negative effects of maternal PKU. JAMA 2000;283:756–762
Double-beta decay in gauge theories
2000-07-01

Neutrinoless double beta decay is a very important process both from the particle and nuclear physics point of view. Its observation will severely constrain the existing models and signal that the neutrinos are massive Majorana particles. From the elementary particle point of view it pops up in almost every model. In addition to the traditional mechanisms, like the neutrino mass, the admixture of right handed currents etc, it may occur due to the R-parity violating supersymmetric (SUSY) interactions. From the nuclear physics point of view it is challenging, because: 1) The relevant nuclei have complicated nuclear structure. 2) The energetically allowed transitions are exhaust a small part of all the strength. 3) One must cope with the short distance behavior of the transition operators, especially when the intermediate particles are heavy (eg in SUSY models). Thus novel effects, like the double beta decay of pions in flight between nucleons, have to be considered. 4) The intermediate momenta involved are about 100 MeV. Thus one has to take into account possible momentum dependent terms in the nucleon current. We find that, for the mass mechanism, such modifications of the nucleon current for light neutrinos reduce the nuclear matrix elements by about 25 per cent, almost regardless of the nuclear model. In the case of heavy neutrinos the effect is much larger and model dependent. Taking the above effects into account, the available nuclear matrix elements for the experimentally interesting nuclei A = 76, 82, 96, 100, 116, 128, 130, 136 and 150 and the experimental limits on the life times we have extracted new stringent limits on the average neutrino mass and on the R-parity violating coupling for various SUSY models.