Endometrial NK cells are special immature cells that await pregnancy

NK cells populate the human endometrium before pregnancy. Unlike decidual NK cells that populate the decidua during pregnancy, the NK cells present in the human endometrium, before pregnancy, have not been fully characterized. In this study, we provide a detailed analysis of the origin, phenotype, and function of endometrial NK cells (eNK). We show that eNK cells have a unique receptor repertoire. In particular, they are negative for NKp30 and chemokine receptor expression, which distinguishes them from any other NK subset described so far. We further show that eNK cells lack NK-specific functional phenotype and activity such as cytokine secretion and cytotoxicity, before IL-15 stimulation. Following such stimulation, endometrial NK cells acquire phenotype and function that are similar to those of decidual NK cells. We therefore suggest that eNK cells are inactive cells (before IL-15 activation and in relation to the known NK activity) that are present in the endometrium before conception, waiting for pregnancy.     

Role of Ser-340 and Thr-341 in transmembrane domain IX of the Na+/proline transporter PutP of Escherichia coli in ligand binding and transport

The Na+/solute symporter family comprises more than 400 members of pro- and eukaryotic origin. Using the Na+/proline transporter PutP of Escherichia coli as a model, the role of two conserved residues, Ser-340 and Thr-341, is investigated to obtain insights into the mechanism of transport catalyzed by members of this family. Substitution of these amino acids alters the transport kinetics of cells and proteoliposomes containing the PutP variants significantly. In particular, the apparent affinities for Na+ and Li+ are reduced by 2 orders of magnitude or more. Also proline binding is affected, albeit to a lesser extent than ion binding. Thereby, the presence of a hydroxyl group at position 341 is essential for high affinity ligand binding. Furthermore, Cys placed at position 340 or 341 reacts with sulfhydryl reagents of different polarity, indicating accessibility from the water phase. In addition, Cys cross-linking suggests proximity of the residues to other amino acids previously shown to be crucial for ligand binding. For these reasons it is suggested that Ser-340 and Thr-341 are located in a ligand translocation pathway. Furthermore, it is proposed that the side chain of Thr-341 directly participates in Na+ binding.     

Force-induced structural transitions in cross-linked DNA films

We report on the preparation and characterization of wet-spun films of sodium DNA in which intermolecular cross-links were introduced following formaldehyde treatment. Raman scattering shows that the DNA in moderately cross-linked films is mainly in the B conformation. Stretching experiments show a transition from plastic to elastomeric behavior with increasing exposure to the cross-linking agent. Elastomeric DNA films are strongly disordered. X-ray diffraction shows that stretching of moderately cross-linked films under controlled high humidity conditions results in increased molecular orientation as well as the appearance of meridional reflections at 7.4-7.8 and 8.2 A. These reflections are not observed for any of the classical conformations associated with mixed sequence DNA, and may arise from extended base-pair stacking in a stretched DNA structure.     

Effect of egg‐phosphatidylcholine on the chilling sensitivity and lipid phase transition of Asian elephant (Elephas maximus) spermatozoa

This study was conducted in an effort to improve our understanding of the response of Asian elephant (Elephas maximus, Em) spermatozoa to chilling. Semen was collected from two elephant bulls by means of the manual rectal stimulation method. Five out of seven semen collections were deemed to be suitable for use based on motility (ranging from 20% to 60%) and membrane integrity. We evaluated the chilling sensitivity by incubating the sperm with a fluorescent dye (5‐carboxyfluorescein diacetate (cFDA)) at 16°C, 12°C, 4°C, and 22°C (control). Cells with an intact membrane retained the dye and were identified as viable. The membrane lipid phase transition (LPT) temperature curve was determined with a Fourier transform infrared (FTIR) spectrometer connected to an FTIR microscope. The LPT center, T_m, was determined by statistical analysis. The LPT and T_m were also assessed in fresh spermatozoa and spermatozoa incubated with egg yolk or egg‐phosphatidylcholine (EPC) liposomes at 16°C, 12°C, 4°C, and 26°C (control). The results show that the membrane integrity of spermatozoa incubated at 16°C, 12°C, and 4°C decreased by 39%, 62%, and 67%, respectively, compared to the control. The LPT temperatures were between room temperature (26°C) and 10°C, with T_m at 14–16°C. The T_m for sperm incubated with liposomes or egg‐yolk extender was below the measured range (2°C). Chilling sensitivity was found at a wide range of temperatures and transition temperatures, suggesting the presence of a wide variety of fatty acids (FAs) in the membrane with a high ratio of saturated‐to‐polyunsaturated FAs. Here we show that the protection afforded by the presence of egg yolk or liposomes in the extender is accomplished by shifting the T_m to below the 4°C point at which chilled semen is maintained for transport, or the point at which fast freezing begins to minimize cellular damage. Zoo Biol 0:1–13, 2005. © 2005 Wiley‐Liss, Inc.     

Fluctuations of cellular, available zinc modulate insulin signaling via inhibition of protein tyrosine phosphatases.

Extracellular zinc ions are effectors of many signaling pathways in mammalian cells, including the insulin/IGF-1 pathway. Molecular targets of zinc are intracellular, however, because otherwise ineffective zinc concentrations alter the extent of protein phosphorylation only in the presence of the ionophore pyrithione. The tight inhibition of protein tyrosine phosphatases by zinc (nanomolar inhibition constants) is likely responsible for the known insulinomimetic effects of zinc ions, which increase net phosphorylation of the insulin/IGF-1-receptors and activate their signaling cascades. More importantly, not only do extracellular zinc ions affect signal transduction, but growth factors induce cellular zinc fluctuations that are of sufficient magnitude to inhibit protein tyrosine phosphatases. In conclusion, a pool of cellular, available zinc participates in phosphorylation/dephosphorylation cascades, suggesting the existence of a cellular signaling system based on zinc as a second messenger.     

Gamma-tocopherol supplementation alone and in combination with alpha-tocopherol alters biomarkers of oxidative stress and inflammation in subjects with metabolic syndrome

Metabolic syndrome (MetS) is associated with increased incidence of diabetes and cardiovascular disease (CVD). Prospective clinical trials with alpha-tocopherol (AT) have not yielded positive results. Because AT supplementation decreases circulating gamma-tocopherol (GT), we evaluated supplementation with GT (800 mg/day), AT (800 mg/day), the combination or placebo for 6 weeks alone AT and GT concentrations, biomarkers of oxidative stress, and inflammation in subjects with MetS (n=20/group). Plasma AT and GT levels increased following supplementation with AT alone or GT alone or in combination. AT supplementation significantly decreased GT levels. Urinary alpha- and gamma-CEHC, metabolites of the respective Ts, also increased correspondingly, i.e., alpha-CEHC with AT and gamma-CEHC with GT supplementation, compared to placebo. HsCRP levels significantly decreased in the combined AT+GT group. LPS-activated whole blood release of IL-1 and IL-6 did not change. There was a significant decrease in TNF with AT alone or in combination with GT. Plasma MDA/HNE and lipid peroxides were significantly decreased with AT, GT, or in combination. Nitrotyrosine levels were significantly decreased only with GT or GT+AT but not with AT compared to placebo. Thus, the combination of AT and GT supplementation appears to be superior to either supplementation alone on biomarkers of oxidative stress and inflammation and needs to be tested in prospective clinical trials to elucidate its utility in CVD prevention.     

Vitamin E revisited: do new data validate benefits for chronic disease prevention?

PURPOSE OF REVIEW: Vitamin E benefits in human health and chronic disease prevention are evaluated with respect to established alpha-tocopherol functions during vitamin E deficiency, adequacy, and excess. RECENT FINDINGS: Baseline vitamin E status of the 29 092 Finnish men participating in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention study showed that the men in the highest compared with the lowest quintile of serum alpha-tocopherol had significantly lower incidences of total and cause-specific mortality. New findings from the Women's Health Study support a role for vitamin E supplements in decreasing the risk for sudden death from cardiovascular disease and from thromboembolism. We speculate that a potential mechanism may involve vitamin E interference in vitamin K activation. SUMMARY: alpha-Tocopherol acts as a peroxyl and alkoxyl radical scavenger in lipid environments, and thus it prevents lipid peroxidation in lipoproteins and membranes, especially nervous tissues. Decreased chronic disease incidence is associated with lifelong generous dietary vitamin E intakes, but more than 90% of Americans do not consume the recommended dietary amounts (15 mg/day). Vitamin E supplements can have beneficial effects on health beyond those from dietary amounts, perhaps because pharmacologic levels also upregulate hepatic xenobiotic pathways.     

Towards a unified paradigm for sequence‐based identification of fungi

The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for the exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference data set and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here, we report on progress in these regards through further development of the UNITE database ( http://unite.ut.ee ) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g. Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third‐party annotation effort. We introduce the term ‘species hypothesis’ (SH) for the taxa discovered in clustering on different similarity thresholds (97–99%). An automatically or manually designated sequence is chosen to represent each such SH. These reference sequences are released ( http://unite.ut.ee/repository.php ) for use by the scientific community in, for example, local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new Web‐based sequence management system in UNITE.     

Hereditary isolated renal magnesium loss maps to chromosome 11q23.

Hypomagnesemia due to isolated renal magnesium loss has previously been demonstrated in two presumably unrelated Dutch families with autosomal dominant mode of inheritance. Patients with magnesium deficiency may suffer from tetany and convulsions, but the patients with hereditary renal magnesium wasting can also be clinically nonsymptomatic. In a genomewide linkage study, we first excluded a possible candidate region, on chromosome 9q, that encompasses the gene for intestinal hypomagnesemia with secondary hypocalcemia and, subsequently, found linkage to markers on chromosome 11q23. Detailed haplotype analyses identified a common haplotype segregating in both families, suggesting both their relationship through a common ancestor and the existence of a single, hypomagnesemia-causing mutation within them. The maximum two-point LOD score (Zmax) was found for marker D11S4127 (Zmax=6.41 at a recombination fraction of. 00), whereas a multipoint analysis gave a Zmax of 8.24 between markers D11S4142 and D11S4171. Key recombination events define a 5. 6-cM region between these two markers on chromosome 11q23. We conclude that this region encompasses a gene, involved in renal magnesium handling, that is mutated in our patients and is different from the gene involved in intestinal magnesium handling.     

Phylogenetic taxonomy of Hymenochaete and related genera (Hymenochaetales)

Species delimitation in Hymenochaete sensu lato was evaluated based on partial nucLSU rDNA sequences, isoenzyme analyses and morphological data. Analyses of LSU data revealed Hymenochaete sensu stricto and Pseudochaete as distinct monophyletic genera. Transfer of Hydnochaete olivacea into genus Pseudochaete and Dichochaete setosa into genus Hymenochaete (as H. resupinata) was supported by the results of molecular analyses. A new species Hymenochaete koeljalgii from Tanzania was described. The species of genus Hymenochaete sensu stricto were divided into four well-supported clades possessing no distinctive morphological characters.