1,25-Dihydroxyvitamin D3 inhibits ultraviolet B-induced apoptosis,Jun kinase activation,and interleukin-6 production in primary human keratinocytes

We investigated the capacity of 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] to protect human keratinocytes against the hazardous effects of ultraviolet B (UVB)-irradiation, recognized as the most important etiological factor in the development of skin cancer. Cytoprotective effects of 1,25(OH)(2)D(3) on UVB-irradiated keratinocytes were seen morphologically and quantified using a colorimetric survival assay. Moreover, 1,25(OH)(2)D(3) suppressed UVB-induced apoptotic cell death. An ELISA, detecting DNA-fragmentation, demonstrated that pretreatment of keratinocytes with 1,25(OH)(2)D(3) 1 microM for 24 h reduced UVB-stimulated apoptosis by 55-70%. This suppression required pharmacological concentrations 1,25(OH)(2)D(3) and a preincubation period of several hours. In addition, 1,25(OH)(2)D(3) also inhibited mitochondrial cytochrome c release (90%), a hallmark event of UVB-induced apoptosis. Furthermore, we demonstrated that 1,25(OH)(2)D(3) reduced two important mediators of the UV-response, namely, c-Jun-NH(2)-terminal kinase (JNK) activation and interleukin-6 (IL-6) production. As shown by Western blotting, pretreatment of keratinocytes with 1,25(OH)(2)D(3) 1 microM diminished UVB-stimulated JNK activation with more than 30%. 1,25(OH)(2)D(3) treatment (1 microM) reduced UVB-induced IL-6 mRNA expression and secretion with 75-90%. Taken together, these findings suggest the existence of a photoprotective effect of active vitamin D(3) and create new perspectives for the pharmacological use of active vitamin D compounds in the prevention of UVB-induced skin damage and carcinogenesis.     

Insights into the bile acid transportation system: the human ileal lipid-binding protein-cholyltaurine complex and its comparison with homologous structures

Bile acids are generated in vivo from cholesterol in the liver, and they undergo an enterohepatic circulation involving the small intestine, liver, and kidney. To understand the molecular mechanism of this transportation, it is essential to gain insight into the three-dimensional (3D) structures of proteins involved in the bile acid recycling in free and complexed form and to compare them with homologous members of this protein family. Here we report the solution structure of the human ileal lipid-binding protein (ILBP) in free form and in complex with cholyltaurine. Both structures are compared with a previously published structure of the porcine ILBP-cholylglycine complex and with related lipid-binding proteins. Protein structures were determined in solution by using two-dimensional (2D)- and 3D-homo and heteronuclear NMR techniques, leading to an almost complete resonance assignment and a significant number of distance constraints for distance geometry and restrained molecular dynamics simulations. The identification of several intermolecular distance constraints unambiguously determines the cholyltaurine-binding site. The bile acid is deeply buried within ILBP with its flexible side-chain situated close to the fatty acid portal as entry region into the inner ILBP core. This binding mode differs significantly from the orientation of cholylglycine in porcine ILBP. A detailed analysis using the GRID/CPCA strategy reveals differences in favorable interactions between protein-binding sites and potential ligands. This characterization will allow for the rational design of potential inhibitors for this relevant system.     

Synthesis and conformation of four 16,17-diols in the 3-methoxy-13alpha-estra-1,3,5(10)-triene series

All four diasteromeric 16,17-diols in the 3-methoxy-13alpha-estra-1,3,5(10)-triene series have been synthesized. The trans-diols 1 and 2 can be obtained by hydroborating the 17-enol acetate 6 (61%, ratio 27:73, preferred alpha attack). OsO(4) dihydroxylation of the olefin 7 yielded the cis-diols 3 and 4 (ratio 13:87). The dihydroxylation proceeds with preference for beta attack caused by a C-ring twist-boat form of 7. The conformations of the diols 2 and 4, the 17-benzyl-17-hydroxy compounds 9 and 10 (obtained by Grignard reaction), and the 16alpha-bromo-17beta-hydroxy compound 8 were determined by X-ray analysis and by 1H NMR spectroscopy in solution. Some compounds, in spite of a 17beta-hydroxy group, had a conformation with a ring C chair form (4, 8, 9) caused by intermolecular interaction in the solid state. The rest of the compounds studied here (2, 10) possessed a conformation with a ring C twist-boat form, which has been also found for all 17beta-substituted compounds in solution. The preferred conformation of the D-ring with 17beta-substituents seems to be the 16beta-envelope form or near this form, but the existence of the 16alpha-envelope form (inversion of the ring D) for some compounds showed great variance in the conformation of ring D, which is substituent dependent.     

Production,storability, and regeneration of shoot tips of potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) encapsulated in calcium alginate hollow beads

Summary Shoot tips, of four potato cultivars (Désirée, Genet, Tigoni, and Tomensa), 3–4 mm in size, were precultured for 2 d on Murashige and Skoog (MS) solid medium, then encapsulated in calcium alginate to produce hollow bead synthetic seed capsules averaging 0.78 cm in diameter. Regeneration and ‘regrowth’ were tested on MS solid medium and on soil in the greenhouse, respectively. The encapsulated shoot tips were stored at 4 and 10°C for up to 390 d. For all cultivars, the encapsulated shoot tips stored at both temperatures for 180 d and at 4°C,for 270 d, 100% regeneration on MS solid medium was recorded. After 360 d in storage at 4°C, 70.8% (Tigoni), 66.7% (Genet), 58.3% (Désirée), and 51.5% (Tomensa) regeneration was recorded on MS medium, reducing to 15% (Tigoni), 25% (Genet), 10% (Désirée), and 0% (Tomensa) regeneration after 390 d in storage. ‘Regrowth’ of 93–100% was recorded for non-stored encapsulated shoot tips, directly transferred on soil in the greenhouse after a 2 wk preculture on MS solid medium with an added fungicide (carbendazim) in the encapsulating gel. The ‘regrown’ shoot tips produced plants showing normal development. The results presented here demonstrate that hollow bead synthetic seed capsules are an alternative propagating method for potato seed production.     

Residues of the fourth transmembrane segments of the Na,K-ATPase and the gastric H,K-ATPase contribute to cation selectivity

We have generated protein chimeras to investigate the role of the fourth transmembrane segments (TM4) of the Na,K- and gastric H, K-ATPases in determining the distinct cation selectivities of these two pumps. Based on a helical wheel analysis, three residues of TM4 of the Na,K-ATPase were changed to their H,K-counterparts. A construct carrying three mutations in TM4 (L319F, N326Y, and T340S) and two control constructs were heterologously expressed in Xenopus laevis oocytes and in the pig kidney epithelial cell line LLC-PK(1). Biochemical ATPase assays demonstrated a large sodium-independent ATPase activity at pH 6.0 for the pump carrying the TM4 substitutions, whereas the control constructs exhibited little or no activity in the absence of sodium. Furthermore, at pH 6.0 the K(1/2)(Na(+)) shifted to 1.5 mM for the TM4 construct compared with 9.4 and 5.9 mM for the controls. In contrast, at pH 7.5 all three constructs had characteristics similar to wild type Na,K-ATPase. Large increases in K(1/2)(K(+)) were observed for the TM4 construct compared with the control constructs both in two-electrode voltage clamp experiments in Xenopus oocytes and in ATPase assays. ATPase assays also revealed a 10-fold shift in vanadate sensitivity for the TM4 construct. Based on these findings, it appears that the three identified TM4 residues play an important role in determining both the specific cation selectivities and the E(1)/E(2) conformational equilibria of the Na,K- and H,K-ATPase.     

Territorial- und Werbeverhalten des Chinahaselhuhns(Bonasa sewerzowi)

Zusammenfassung Zwischen 2. und 10. Mai 1997, dem Höhepunkt territorialer Aktivität, wurden im Lianhuashan-Reservat (Gansu, China) Territorial- und Werbeverhalten anhand von 18 farbberingten und besenderten Chinahaselhühnern mittels Ton- und Videotechnik verfolgt. Die Hähne markieren ihre Reviere durch instrumentale Flügelgeräusche, die durch Flattersprünge am Boden, seltener durch Revierflüge hervorgebracht werden. Die Flattersprunghäufigkeit kulminiert am frühen Morgen, die Nahrungsaufnahme am Abend. Die erste Paarung fand am 9. Mai statt.

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Territorial and courtship behaviour of Chinese Grouse(Bonasa sewerzowi)

Summary Field observations, sound and video recordings of the rare endemic Chinese Grouse were carried out during May 2 and 10, 1997, the optimal time to study display, in the Lianhuashan reserve (Gansu province) at altitudes between 2800 and 3200 m a.s.l. We found the density in spring extraordinarily high: 15 occupied territories/km² in the best studied plot. 18 colour-banded and radio-tagged birds were recorded. We were able to record on tape most of the vocal and instrumental sounds produced by the displaying grouse. Chinese grouse males perform a wing-beat display. The main elements of the territorial activity were variable flutter-jumps on the ground up to 1 m high and 2–4 m wide, sometimes also from a tree to the ground and vice-versa, producing instrumental sounds. An evident peak of flutter jumping activity was observed just after the birds left the roost tree in the morning (5.30 h local time) up to 8 o'clock. Noisy territorial flights in the crowns of trees were rarely observed. The low frequency sounds produced by the wings of the jumping cocks produced a typical impressive morning concert, especially, if 3–4 conflicting males came close together. First copulation was recorded on May 9. In the mating time, flutter jumping activity abated considerably.

     

Linking Integrin α6β4-based Cell Adhesion to the Intermediate Filament Cytoskeleton: Direct Interaction between the β4 Subunit and Plectin at Multiple Molecular Sites

Recent studies with patients suffering from epidermolysis bullosa simplex associated with muscular dystrophy and the targeted gene disruption in mice suggested that plectin, a versatile cytoskeletal linker and intermediate filament-binding protein, may play an essential role in hemidesmosome integrity and stabilization. To define plectin's interactions with hemidesmosomal proteins on the molecular level, we studied its interaction with the uniquely long cytoplasmic tail domain of the β₄ subunit of the basement membrane laminin receptor integrin α₆β₄ that has been implicated in connecting the transmembrane integrin complex with hemidesmosome-anchored cytokeratin filaments. In vitro binding and in vivo cotransfection assays, using recombinant mutant forms of both proteins, revealed their direct interaction via multiple molecular domains. Furthermore, we show in vitro self-interaction of integrin β₄ cytoplasmic domains, as well as disruption of intermediate filament network arrays and dislocation of hemidesmosome-associated endogenous plectin upon ectopic overexpression of this domain in PtK2 and/or 804G cells. The close association of plectin molecules with hemidesmosomal structures and their apparent random orientation was indicated by gold immunoelectron microscopy using domain-specific antibodies. Our data support a model in which plectin stabilizes hemidesmosomes, via directly interlinking integrin β₄ subunits and cytokeratin filaments.     

European populations of Diabrotica virgifera virgifera are resistant to aldrin,but not to methyl‐parathion

The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of cultivated corn in North America and has recently begun to invade Europe. In addition to crop rotation, chemical control is an important option for D. v. virgifera management. However, resistance to chemical insecticides has evolved repeatedly in the USA. In Europe, chemical control strategies have yet to be harmonized and no surveys of insecticide resistance have been carried out. We investigated the resistance to methyl‐parathion and aldrin of samples from nine D. v. virgifera field populations originating from two European outbreaks thought to have originated from two independent introductions from North America. Diagnostic concentration bioassays revealed that all nine D. v. virgifera field populations were resistant to aldrin but susceptible to methyl‐parathion. Aldrin resistance was probably introduced independently, at least twice, from North America into Europe, as there is no evident selection pressure to account for an increase of frequency of aldrin resistance in each of the invasive outbreaks in Europe. Our results suggest that organophosphates, such as methyl‐parathion, may still provide effective control of both larval and adult D. v. virgifera in the European invasive outbreaks studied.     

Short-Term Heart Rate Variability—Influence of Gender and Age in Healthy Subjects

In the recent years, short-term heart rate variability (HRV) describing complex variations of beat-to-beat interval series that are mainly controlled by the autonomic nervous system (ANS) has been increasingly analyzed to assess the ANS activity in different diseases and under various conditions. In contrast to long-term HRV analysis, short-term investigations (<30 min) provide a test result almost immediately. Thus, short-term HRV analysis is suitable for ambulatory care, patient monitoring and all those applications where the result is urgently needed. In a previous study, we could show significant variations of 5-min HRV indices according to age in almost all domains (linear and nonlinear) in 1906 healthy subjects from the KORA S4 cohort. Based on the same group of subjects, general gender-related influences on HRV indices are to be determined in this study. Short-term 5-min HRV indices from linear time and frequency domain and from nonlinear methods (compression entropy, detrended fluctuation analysis, traditional and segmented Poincaré plot analysis, irreversibility analysis, symbolic dynamics, correlation and mutual information analysis) were determined from 782 females and 1124 males. First, we examined the gender differences in two age clusters (25–49 years and 50–74 years). Secondly, we investigated the gender-specific development of HRV indices in five age decade categories, namely for ages 25–34, 35–44, 45–54, 55–64 and 65–74 years. In this study, significant modifications of the indices according to gender could be obtained, especially in the frequency domain and correlation analyses. Furthermore, there were significant modifications according to age in nearly all of the domains. The gender differences disappeared within the last two age decades and the age dependencies disappeared in the last decade. To summarize gender and age influences need to be considered when performing HRV studies even if these influences only partly differ.