High-Precision Determination of g Factors and Masses of ^{20}Ne^{9+} and ^{22}Ne^{9+}

We present the measurements of individual bound electron g factors of ^{20}Ne^{9+} and ^{22}Ne^{9+} on the relative level of 0.1 parts per billion. The comparison with theory represents the most stringent test of bound-state QED in strong electric fields. A dedicated mass measurement results in m(^{20}Ne)=19.992 440 168 77(9)  u, which improves the current literature value by a factor of 18, disagrees by 4 standard deviations, and represents the most precisely measured mass value in atomic mass units. Together, these measurements yield an electron mass on the relative level of 0.1 ppb with m_{e}=5.485 799 090 99(59)×10^{-4}  u as well as a factor of seven improved m(^{22}Ne)=21.991 385 098 2(26)  u.

Part-night exposure to artificial light at night has more detrimental effects on aphid colonies than fully lit nights

Artificial light at night (ALAN) threatens natural ecosystems globally. While ALAN research is increasing, little is known about how ALAN affects plants and interactions with other organisms. We explored the effects of ALAN on plant defence and plant-insect interactions using barley (Hordeum vulgare) and the English grain aphid (Sitobion avenae). Plants were exposed to 'full' or 'part' nights of 15-20 lux ALAN, or no ALAN 'control' nights, to test the effects of ALAN on plant growth and defence. Although plant growth was only minimally affected by ALAN, aphid colony growth and aphid maturation were reduced significantly by ALAN treatments. Importantly, we found strong differences between full-night and part-night ALAN treatments. Contrary to our expectations, part ALAN had stronger negative effects on aphid colony growth than full ALAN. Defence-associated gene expression was affected in some cases by ALAN, but also positively correlated with aphid colony size, suggesting that the effects of ALAN on plant defences are indirect, and regulated via direct disruption of aphid colonies rather than via ALAN-induced upregulation of defences. Mitigating ecological side effects of ALAN is a complex problem, as reducing exposure to ALAN increased its negative impact on insect herbivores. This article is part of the theme issue 'Light pollution in complex ecological systems'.

Stringent test of QED with hydrogen-like tin

Inner-shell electrons naturally sense the electric field close to the nucleus, which can reach extreme values beyond 1015 V cm-1 for the innermost electrons1. Especially in few-electron, highly charged ions, the interaction with the electromagnetic fields can be accurately calculated within quantum electrodynamics (QED), rendering these ions good candidates to test the validity of QED in strong fields. Consequently, their Lamb shifts were intensively studied in the past several decades2,3. Another approach is the measurement of gyromagnetic factors (g factors) in highly charged ions4-7. However, so far, either experimental accuracy or small field strength in low-Z ions5,6 limited the stringency of these QED tests. Here we report on our high-precision, high-field test of QED in hydrogen-like 118Sn49+. The highly charged ions were produced with the Heidelberg electron beam ion trap (EBIT)8 and injected into the ALPHATRAP Penning-trap setup9, in which the bound-electron g factor was measured with a precision of 0.5 parts per billion (ppb). For comparison, we present state-of-the-art theory calculations, which together test the underlying QED to about 0.012%, yielding a stringent test in the strong-field regime. With this measurement, we challenge the best tests by means of the Lamb shift and, with anticipated advances in the g-factor theory, surpass them by more than an order of magnitude.

The right not to know: Non-disclosure of primary genetic test results and genetic counselors' response

As part of clinical genetic counseling practice, patients may request that their primary genetic test results be disclosed to someone else, such as a relative or referring provider, or request that results be disclosed to no one (non-disclosure). In making these requests, patients employ the ethical principle of the "right not to know," which argues that autonomous individuals can choose not to know relevant health information. Although the right not to know has been well-studied in medicine in general, and in the return of genomic secondary findings, we are not aware of other studies that have explored the return of primary genetic test results when patients request non-disclosure or disclosure to another individual. This study aimed to describe common clinical scenarios in which these requests occur, how genetic counselors respond, and what ethical considerations they employ in their decision-making process. We recruited participants from the National Society of Genetic Counselors' (NSGC) "Student Research Surveys and Reminders" listserv and conducted semi-structured interviews with 11 genetic counselors in the United States who described genetic counseling cases where this occurred. Interviews were transcribed and coded inductively, and themes were identified. Case details varied, but in our study data the requests for non-disclosure were most commonly made by patients with poor, often oncologic, prognoses who requested their test results be disclosed to a family member instead of themselves. Genetic counselors considered similar factors in deciding how to respond to these requests: patient autonomy, medical actionability of results for the patient and family, the relationship between the patient and the person to whom results might be disclosed, and legal or practical concerns. Genetic counselors often made decisions on a case-by-case basis, depending on how relevant each of these factors were. This study adds to the growing body of literature regarding patients' "right not to know" and will hopefully provide guidance for genetic counselors who experience this situation in clinical practice.

Penning-Trap Mass Measurement of Helium-4

Light-ion trap (LIONTRAP), a high-precision Penning-trap mass spectrometer, was used to determine the atomic mass of ^{4}He. Here, we report a 12 parts-per-trillion measurement of the mass of a ^{4}He^{2+} ion, m(^{4}He^{2+})=4.001 506 179 651(48)  u. From this, the atomic mass of the neutral atom can be determined without loss of precision: m(^{4}He)=4.002 603 254 653(48)  u. This result is slightly more precise than the current CODATA18 literature value but deviates by 6.6 standard deviations.

Floral presence and flower identity alter cereal aphid endosymbiont communities on adjacent crops

Floral plantings adjacent to crops fields can recruit populations of natural enemies by providing flower nectar and non-crop prey to increase natural pest regulation. Observed variation in success rates might be due to changes in the unseen community of endosymbionts hosted by many herbivorous insects, of which some can confer resistance to natural enemies, for example, parasitoid wasps. Reduced insect control may occur if highly protective symbiont combinations increase in frequency via selection effects, and this is expected to be stronger in lower diversity systems.We used a large-scale field trial to analyse the bacterial endosymbiont communities hosted by cereal aphids Sitobion avenae collected along transects into strip plots of barley plants managed by either conventional or integrated (including floral field margins and reduced inputs) methods. In addition, we conducted an outdoor pot experiment to analyse endosymbionts in S. avenae aphids collected on barley plants that were either grown alone or alongside one of three flowering plants, across three time points.In the field, aphids hosted up to four symbionts. The abundance of aphids and parasitoid wasps was reduced towards the middle of all fields while aphid symbiont species richness and diversity decreased into the field in conventional, but not integrated, field-strips. The proportion of aphids hosting different symbiont combinations varied across cropping systems, with distances into the fields, and were correlated with parasitoid wasp abundances.In the pot experiment, aphids hosted up to six symbionts. Flower presence increased natural enemy abundance and diversity, and decreased aphid abundance. The proportion of aphids hosting different symbiont combinations varied across the flower treatment and time, and were correlated with varying abundances of the different specialist parasitoid wasp species recruited by different flowers. Synthesis and applications. Floral plantings and flower identity had community-wide impacts on the combinations of bacterial endosymbionts hosted by herbivorous insects, which correlated with natural enemy diversity and abundance. We recommend that integrated management practices incorporate floral resources within field areas to support a more functionally diverse and resilient natural enemy community to mitigate selection for symbiont-mediated pest resistance throughout the cropping area.

Direct Q-Value Determination of the β^{-} Decay of ^{187}Re

The cyclotron frequency ratio of ^{187}Os^{29+} to ^{187}Re^{29+} ions was measured with the Penning-trap mass spectrometer PENTATRAP. The achieved result of R=1.000 000 013 882(5) is to date the most precise such measurement performed on ions. Furthermore, the total binding-energy difference of the 29 missing electrons in Re and Os was calculated by relativistic multiconfiguration methods, yielding the value of ΔE=53.5(10)  eV. Finally, using the achieved results, the mass difference between neutral ^{187}Re and ^{187}Os, i.e., the Q value of the β^{-} decay of ^{187}Re, is determined to be 2470.9(13) eV.

g Factor of Lithiumlike Silicon: New Challenge to Bound-State QED

The recently established agreement between experiment and theory for the g factors of lithiumlike silicon and calcium ions manifests the most stringent test of the many-electron bound-state quantum electrodynamics (QED) effects in the presence of a magnetic field. In this Letter, we present a significant simultaneous improvement of both theoretical g_{th}=2.000 889 894 4 (34) and experimental g_{exp}=2.000 889 888 45 (14) values of the g factor of lithiumlike silicon ^{28}Si^{11+}. The theoretical precision now is limited by the many-electron two-loop contributions of the bound-state QED. The experimental value is accurate enough to test these contributions on a few percent level.

g Factor of Boronlike Argon ^{40}Ar^{13+}

We have measured the ground-state g factor of boronlike argon ^{40}Ar^{13+} with a fractional uncertainty of 1.4×10^{-9} with a single ion in the newly developed Alphatrap double Penning-trap setup. The value of g=0.663 648 455 32(93) obtained here is in agreement with our theoretical prediction of 0.663 648 12(58). The latter is obtained accounting for quantum electrodynamics, electron correlation, and nuclear effects within the state-of-the-art theoretical methods. Our experimental result distinguishes between existing predictions that are in disagreement, and lays the foundations for an independent determination of the fine-structure constant.

Effect of plant chemical variation and mutualistic ants on the local population genetic structure of an aphid herbivore

Plants exhibit impressive genetic and chemical diversity, not just between species but also within species, and the importance of plant intraspecific variation for structuring ecological communities is well known. When there is variation at the local population level, this can create a spatially heterogeneous habitat for specialised herbivores potentially leading to non-random distribution of individuals across host plants. Plant variation can affect herbivores directly and indirectly via a third species, resulting in variable herbivore growth rates across different host plants. Herbivores also exhibit within-species variation, with some genotypes better adapted to some plant variants than others. We genotyped aphids collected across 2 years from a field site containing ~200 patchily distributed host plants that exhibit high chemical diversity. The distribution of aphid genotypes, their ant mutualists, and other predators was assessed across the plants. We present evidence that the local distribution of aphid (Metopeurum fuscoviride) genotypes across host-plant individuals is associated with variation in the plant volatiles (chemotypes) and non-volatile metabolites (metabotypes) of their host plant tansy (Tanacetum vulgare). Furthermore, these interactions in the field were influenced by plant-host preferences of aphid-mutualist ants. Our results emphasise that plant intraspecific variation can structure ecological communities not only at the species level but also at the genetic level within species and that this effect can be enhanced through indirect interactions with a third species.

The Heidelberg compact electron beam ion traps

Electron beam ion traps (EBITs) are ideal tools for both production and study of highly charged ions (HCIs). In order to reduce their construction, maintenance, and operation costs, we have developed a novel, compact, room-temperature design, the Heidelberg Compact EBIT (HC-EBIT). Four already commissioned devices operate at the strongest fields (up to 0.86 T) reported for such EBITs using permanent magnets, run electron beam currents up to 80 mA, and energies up to 10 keV. They demonstrate HCI production, trapping, and extraction of pulsed Ar¹⁶⁺ bunches and continuous 100 pA ion beams of highly charged Xe up to charge state 29+, already with a 4 mA, 2 keV electron beam. Moreover, HC-EBITs offer large solid-angle ports and thus high photon count rates, e.g., in x-ray spectroscopy of dielectronic recombination in HCIs up to Fe²⁴⁺, achieving an electron-energy resolving power of E/ΔE > 1500 at 5 keV. Besides traditional on-axis electron guns, we have also implemented a novel off-axis gun for laser, synchrotron, and free-electron laser applications, offering clear optical access along the trap axis. We report on its first operation at a synchrotron radiation facility demonstrating the resonant photoexcitation of highly charged oxygen.

High-Precision Measurement of the Proton's Atomic Mass

We report on the precise measurement of the atomic mass of a single proton with a purpose-built Penning-trap system. With a precision of 32 parts per trillion our result not only improves on the current CODATA literature value by a factor of 3, but also disagrees with it at a level of about 3 standard deviations.

Four new mitochondrial genomes of the genus zosterops (aves: passeriformes: zosteropidae) from East Africa with a phylogenetic evaluation of the group

The white-eye birds of the genus Zosterops have been recognized for their high speciation rates in the past, but the relationships of the East African populations are not yet fully resolved. We sequenced and annotated mitogenomes of four populations currently assigned to three East African white-eye species, Zosterops senegalensis, Z. abyssinicus and Z. poliogaster. For Z. senegalensis specimens from two distant populations were sequenced; for the other taxa we used samples collected at one site. The mitogenomes ranged between 17,827 and 17,974 bp, in size similar to previously published mitogenomes analyzed for this genus from other geographic regions. The mitogenomes contain the classical set of 13 coding genes, two structural rRNA genes and 22 tRNA genes. We constructed a phylogeny using all complete mitogenomes currently available for the genus. The phylogeny supports an Asian or Oceanic origin of the genus Zosterops. The East African species represent a monophyletic clade, but the two specimens of Zosterops senegalensis from different regions do not group together, supporting previous hypotheses of cryptic species within the genus. The new genetic resources provided here may help to further explore the relationships and evolution of the genus.

Impact of adjustable cryogel properties on the performance of prostate cancer cells in 3D

Background

Biochemical and physical characteristics of extracellular environment play a key role in assisting cell behavior over different molecular pathways. In this study, we investigated how the presence of chemical binding sites, the pore network and the stiffness of designed scaffolds affected prostate cancer cells.

Methods

A blend of poly hydroxyethyl methacrylate–alginate–gelatin scaffold was synthesized by cryogelation process using polyethyleneglycol diacrylate (PEGda) and glutaraldehyde as cross linkers. The chemical and mechanical scaffold properties were varied by concentration of gelatin and PEGda, respectively. The pore network was modified by applying different ‘freezing time’. Growth, spheroid formation and localization of androgen receptor (AR) were measured to evaluate cell response within various cryogel types.

Results

Insufficient porosity in combination with a brittle nature affects cell growth negatively. Spheroid size was reduced by porosity, elasticity as well as by the absence of the cell adhesive motif composed of arginine, glycine und aspartic acid (RGD). Localization of AR indicates its activity and should be under normal culture conditions in the nucleus. But in this study, we could investigate for the first time that AR remains in the cytoplasm when AR positive prostate cancer cells are cultured in scaffolds without RGD as well as in case of an insufficient pore network (total porosity under 10 %) and a too less stiffness of around 10 kPa.

Conclusions

The results indicate that for getting a reliable preclinical drug screening a three-dimensional prostate model system with appropriate biochemical and physical surrounding is needed.

Surgical complications following ESIN for clavicular mid-shaft fractures do not limit functional or patient-perceived outcome

Elastic intramedullary nailing (ESIN) has been proposed as an alternative minimal-invasive method for the operative management of mid-shaft fractures of the clavicle. However, a relevant complication rate has been reported in previous cohorts. The present retrospective single-centre study aimed to analyse the complications following ESIN in adult patients with clavicular mid-shaft fractures (Allman type I) and their impact on functional and patient-perceived outcome measures. Results were compared to a control group receiving locking plate osteosynthesis. The clinical course and outcome of operatively managed patients with clavicular mid-shaft fractures were retrospectively analysed. Patients were assigned to group A (ESIN) and group B (plate fixation). Radiological, functional (Constant Murley Shoulder Outcome Score (CS), the Disabilities of the Arm, Shoulder and Hand (DASH) Score, the Oxford Shoulder Score (OSS)), and patient perceived aesthetic and clinical outcome were measured. A total of 47 (33 male, 14 female) operatively managed patients with a mean age of 26.7 ± 14.9 years and a follow up time of 38.1 ± 19.4 months were analysed. 36 patients were treated by ESIN (Group A), whereas 11 patients received open reduction and internal plate fixation (Group B). Patients were operatively treated with a mean delay of 7.4 ± 9.3 days (group A: 6.6 ± 8.7 days, group B: 10.2 ± 11.1 days, p=0.326) between trauma and the surgical index procedure. There were no significant differences in the functional (CS: p=0.338, DASH: p=0.247, OSS: p=0.434) and patient-perceived (p=0.346) outcome measures between both groups. Surgical complications were noted in 14 patients (group A: 12, group B: 2) and non-union in 4 patients (group A: 3, group B: 1). There was no correlation between the recorded complications as assessed by the Clavien and Dindo classification and the functional as well as the patient-perceived outcome measures. Despite a relevant incidence rate of surgical complications, ESIN provides good to excellent functional and patient-perceived results in the treatment of clavicular mid-shaft fractures.

Searching for the Optimal Sampling Solution: Variation in Invertebrate Communities, Sample Condition and DNA Quality

There is a great demand for standardising biodiversity assessments in order to allow optimal comparison across research groups. For invertebrates, pitfall or flight-interception traps are commonly used, but sampling solution differs widely between studies, which could influence the communities collected and affect sample processing (morphological or genetic). We assessed arthropod communities with flight-interception traps using three commonly used sampling solutions across two forest types and two vertical strata. We first considered the effect of sampling solution and its interaction with forest type, vertical stratum, and position of sampling jar at the trap on sample condition and community composition. We found that samples collected in copper sulphate were more mouldy and fragmented relative to other solutions which might impair morphological identification, but condition depended on forest type, trap type and the position of the jar. Community composition, based on order-level identification, did not differ across sampling solutions and only varied with forest type and vertical stratum. Species richness and species-level community composition, however, differed greatly among sampling solutions. Renner solution was highly attractant for beetles and repellent for true bugs. Secondly, we tested whether sampling solution affects subsequent molecular analyses and found that DNA barcoding success was species-specific. Samples from copper sulphate produced the fewest successful DNA sequences for genetic identification, and since DNA yield or quality was not particularly reduced in these samples additional interactions between the solution and DNA must also be occurring. Our results show that the choice of sampling solution should be an important consideration in biodiversity studies. Due to the potential bias towards or against certain species by Ethanol-containing sampling solution we suggest ethylene glycol as a suitable sampling solution when genetic analysis tools are to be used and copper sulphate when focusing on morphological species identification and facing financial restrictions in biodiversity studies.

Persistence-length renormalization of polymers in a crowded environment of hard disks

The most conspicuous property of a semiflexible polymer is its persistence length, defined as the decay length of tangent correlations along its contour. Using an efficient stochastic growth algorithm to sample polymers embedded in a quenched hard-disk fluid, we find apparent wormlike chain statistics with a renormalized persistence length. We identify a universal form of the disorder renormalization that suggests itself as a quantitative measure of molecular crowding.

Development and validation of a rapid ultra-high performance liquid chromatography diode array detector method for Vitex agnus-castus

A rapid ultra-high performance liquid chromatography diode array detector (UHPLC-DAD) method was developed and validated for the simultaneous determination of all classes of non-volatile phytochemicals (iridoids, flavonoids and diterpenes) in Vitex agnus-castus (Lamiaceae) fruits, a traditional medicinal plant used against premenstrual symptoms (PMS) and other disorders. Seven marker compounds, 3,4-dihydroxybenzoic acid, p-hydroxybenzoic acid, agnuside, 5-hydroxykaempferol-3,6,7,4'-tetramethylether, 1,2-dibenzoic acid glucose, methoxy-vitexilactone, and vitetrifolin D were isolated from the methanol extract of V. agnus-castus to be used as reference substances. Chromatographic separation was performed on a Zorbax Eclipse XDB-C18 (50mm×2.1mm) UHPLC column with 1.8μm particle size, within 20min. A solvent gradient from 0.5% acetic acid to acetonitrile at a flow rate of 0.6mL/min was used as mobile phase. Analyte detection and quantification was realized at 210nm and 260nm. The UHPLC-DAD assay was validated for the quantitative analysis of agnuside, isovitexin, casticin, 5-hydroxykaempferol-3,6,7,4'-tetramethylether and vitetrifolin D. It was found to be specific, accurate, precise, and reproducible for the quantification of these compound within a concentration range of 0.7-500.0μg/mL for casticin and 5-hydroxykaempferol-3,6,7,4'-tetramethylether, 1.4-1000.0μg/mL for isovitexin and agnuside, and 12.4-1000.0μg/mL for vitetrifolin D. Intra- and inter-day variations showed relative standard deviations (RSD) of less than 3.9% and 6.4%, respectively. Tentatively assignment of 62 chromatographic features found in the UHPLC-DAD assay was carried out by coupling the UHPLC instrument to a quadrupole time-of-flight mass spectrometer via an electrospray ionization interface (ESI-QTOF-MS) operated in positive and negative ion mode. By using the established quantitative UHPLC-DAD assay to asses agnuside, isovitexin, casticin, 5-hydroxykaempferol-3,6,7,4'-tetramethylether and vitetrifolin D in V. agnus-castus derived preparations as extracts, tinctures and tablets, the applicability of the developed assay to phytopharmaceuticals was successfully proven.

g Factor of lithiumlike silicon 28Si11+

The g factor of lithiumlike silicon (28)Si(11+) has been measured in a triple-Penning trap with a relative uncertainty of 1.1×10(-9) to be g(exp)=2.000 889 889 9(21). The theoretical prediction for this value was calculated to be g(th)=2.000 889 909(51) improving the accuracy to 2.5×10(-8) due to the first rigorous evaluation of the two-photon exchange correction. The measured value is in excellent agreement with the theoretical prediction and yields the most stringent test of bound-state QED for the g factor of the 1s(2)2s state and the relativistic many-electron calculations in a magnetic field.

g factor of hydrogenlike ²⁸Si¹³⁺

We determined the experimental value of the g factor of the electron bound in hydrogenlike ²⁸Si¹³⁺ by using a single ion confined in a cylindrical Penning trap. From the ratio of the ion's cyclotron frequency and the induced spin flip frequency, we obtain g = 1.995 348 958 7(5)(3)(8). It is in excellent agreement with the state-of-the-art theoretical value of 1.995 348 958 0(17), which includes QED contributions up to the two-loop level of the order of (Zα)² and (Zα)⁴ and represents a stringent test of bound-state quantum electrodynamics calculations.

Formation of core-shell and hollow nanospheres through the nanoscale melt-solidification effect in the Sm-Fe(Ta)-N system

Sm-Fe-Ta-N-O nanospheres were synthesized by pulsed-laser deposition from a Sm(13.8)Fe(82.2)Ta(4.0) target in a nitrogen atmosphere. Three structurally and compositionally distinct types were identified: amorphous, core-shell and hollow nanospheres. Amorphous spheres were compositionally homogeneous and completely oxidized. The core-shell spheres were composed of an iron-rich crystalline core with up to 10 at.% interstitially incorporated nitrogen, surrounded by an amorphous and oxidized shell. The hollow spheres were characterized by voids filled with N(2) gas. It was found that the formation of either amorphous or complex nanospheres is defined by an initial Fe/Sm ratio within the molten droplet. The formation of hollow spheres is believed to be related to the general affinity of liquid metals for gas intake. During rapid solidification the dissolved gas in the melt is trapped within the surrounding solid rim, preventing the outwards diffusion of gas. As long as the amount of gas atoms in the melt is kept below its solubility limits it can be completely interstitially incorporated into the solid, thus forming crystalline Fe(N)-rich cores. If the melt contains more than an equilibrium amount of nitrogen it is possible that the gas recombines to form N(2) molecules, which are condensed inside the spheres.

Genomic organization of the gene for mouse PIASgamma and analysis of its promoter

Signal transducer and transcriptional activator (STAT) proteins are latent cytoplasmic transcription factors that are activated in response to stimulation by various cytokines. Protein Inhibitors of Activated STAT (PIAS) proteins comprise a family of five mammalian proteins which have been identified as potentially important downregulators of the STAT signaling pathway. We have previously reported the identification and expression of the mouse homologue of PIAS family member PIASgamma. Here we report the isolation by genomic 5'-RACE PCR and in vitro analysis of the mouse PIASgamma promoter region and the genomic structure and organization of the mouse and human PIASgamma genes. Human PIASgamma spans approximately 23 kb on chromosome 19 and is organized into ten exons. The size of mouse PIASgamma is 16 kb and also organized into ten exons with the intron/exon structure of the two genes conserved in both species. As a result, considerable conservatism of the mouse and human intron sequences was observed. Analysis of a 1.4 kb genomic fragment containing the mouse PIASgamma promoter allowed us to map the transcription 'Start' site of the gene, determine the sequences essential for the activity of this promoter and to define a minimal promoter region.

Calcineurin A and calbindin immunoreactivity in the spinal cord of G93A superoxide dismutase transgenic mice

A qualitative immunohistochemical study was performed on calcineurin A- and calbindin-positive neurons in the spinal cord of transgenic mice, an animal model of amyotrophic lateral sclerosis, carrying the G93A mutation of the Cu/Zn-superoxide dismutase gene. The results show that calcineurin A-immunoreactive motoneurons are affected by the neurodegenerative process; in contrast, calbindin-positive cells are selectively spared. The findings suggest that calcineurin plays a role as an accessory factor responsible for selective vulnerability in the neurodegenerative process of amyotrophic lateral sclerosis.

New taxonomically significant sesquiterpenoids from Leontodon autumnalis

The methanolic extract of subaerial parts of Leontodon autumnalis afforded four new and two known sesquiterpenoids of the guaiane type. The known compounds were identified by means of (1)H and (13)C NMR spectroscopy as crepidiaside A (1) and B (2). The structures of the new compounds were determined by extensive 1D and 2D NMR experiments as 15-glucopyranosyloxy-2-oxo-guaia-3,11(13)-dien-1alp ha,5alpha, 6beta,7alpha,10alphaH-12,6-olide (3); 15-glucopyranosyloxy-2-oxo-guai-3-en-1alpha,5alpha+ ++,6beta,7alpha, 10alpha,11betaH-12,6-olide (4); 15-hydroxy-2-oxo-guai-3-en-1alpha, 5alpha,6beta,7alpha,10alpha,11betaH-12,6-+ ++olide (5); and 15-glucopyranosyloxy-2-oxo-guaia-3,11(13)-dien-1bet a,5alpha,6beta, 7alpha,10alphaH-12,6-olide (6), respectively. HPLC-DAD and HPLC-MS analyses of crude extracts of subaerial parts of 25 different taxa of the genus Leontodon revealed that compounds 1 and 2 occur in all investigated members of the section Oporinia (L. autumnalis, L. croceus, L. helveticus, L. montaniformis, L. montanus, L. pyrenaicus, and L. rilaensis) and in L. duboisii from the section Kalbfussia. Compounds 1-6 are detectable neither in other investigated taxa of Kalbfussia (L. cichoraceus, L. muelleri, and L. palisae) nor in any members of the subgenus Leontodon. Compounds 3-5 occur in high amounts only in L. croceus and L. pyrenaicus and in samples of L. autumnalis from northwestern Europe. In other members of the section Oporinia, in L. duboisii as well as in samples of L. autumnalis from the Pyrenees, the Alps, the Carpathians, and southern Central Europe, these substances occur only in trace amounts; in L. montanus and its closest relatives, compounds 3-5 are not detectable at all. Compound 6 is only detectable in samples of L. autumnalis, L. helveticus, L. pyrenaicus, L. rilaensis, and L. duboisii.

Cloning and analysis of a murine PIAS family member, PIASgamma, in developing skin and neurons

Signal transducer and activator of transcription (STAT) proteins are latent cytoplasmic transcription factors that become activated in response to stimulation by various cytokines. Recently a new family of five structurally related proteins, called PIAS (Protein Inhibitor of Activated STAT) has been identified as potentially important downregulators of this pathway. Members of the PIAS family of STAT inhibitors may play a prominent role in the downregulation of STAT-mediated signaling processes. In this article we describe the isolation of the cDNA and expression of the gene for the murine homologue of the human STAT inhibitor family member PIASgamma. The cDNA for mPIASgamma encodes a protein of 507 amino acids that is highly homologous to the human protein and is expressed in the mouse as early as d 7.5 of gestation. In situ hybridizations of staged mouse embryos localized the transcript for the PIASgamma gene to the limbs, neuroepithelium, and the inner root sheath of the hair follicle, suggesting a role in the development of these structures. Immunostaining studies with a polyclonal antibody (PAb) recognizing human PIASgamma localized the protein in the hair follicle of human scalp hair and in monkey neuronal cells. Thus PIASgamma exhibits a highly selective pattern of expression, suggesting that it modulates the response of cells to developmental cues.

Analysis of isoquinoline alkaloids in medicinal plants by capillary electrophoresis-mass spectrometry

The technique of capillary electrophoresis - mass spectrometry (CE-MS) was applied for determination of isoquinoline alkaloids in crude methanolic extracts of medicinal plants. For the CE separations ammonium formate buffer solutions (70 or 100 mM, pH 3.0 or 4.0) containing 10% methanol or 20-60% acetonitrile as additives were used. The applied voltage was 25 kV, the thermostating temperature was kept constant at 25 degrees C. Coupling with the mass spectrometer was performed via an atmospherical pressure ionization (API) interface and the electrospray ionization technique (ESI). As sheath liquid 5 mM formic acid in acetonitrile at a flow rate of 3 microL/min was used. The spray voltage was 4.5 kV and the temperature of the heated capillary was chosen to be 200 degrees C. Detection in the positive ionization mode resulted in mass spectra showing either the molecular ions [M]+ or the protonated molecular ions [M+H]+. The presented method allows detection and identification of isoquinoline alkaloids in crude methanolic extracts of medicinal plants as Eschscholzia californica CHAM. (Papaveraceae), Hydrastis canadensis L. (Ranunculaceae), Berberis vulgaris L. (Berberidaceae), Jateorhiza palmata (LAM.) MIERS (Menispermaceae) and Chelidonium majus L. (Papaveraceae).

Domains determining the functional distinction of the fission yeast cell cycle "start" molecules Res1 and Res2

In Schizosaccharomyces pombe the "start" of the cell cycle is regulated by two parallel, functionally overlapping complexes composed of Res1-Cdc10 and Res2-Cdc10. Res1 and Res2 are structurally very homologous and are required for the start of the mitotic and meiotic cycle, respectively. We have addressed the question which parts of the proteins are essential for function and determine the functional specificity. Several discrete domains in the nonconserved C-terminal region are essential for the mitotic and meiotic start function and determine the functional specificity independently of the structurally conserved motifs at the N-terminal end and in the center. One of these domains in Res2 restricts Res2 to interact only with Rep2. Res2 without this domain behaves like a functional chimera having the properties of Res2 and Res1. Likewise, internally truncated forms of Res1 lacking the centrally located ankyrin repeats and adjacent sequences can partially suppress the meiotic defect in res2- cells. These truncated Res1 molecules behave like functional chimeras with the properties of Res1 and Res2.

Lupane derivatives from Lophopetalum wallichii with farnesyl protein transferase inhibitory activity

Chloroform-soluble extracts of the stems and of the mixed stems and stem bark of Lophopetalum wallichii were found to be inhibitory in a farnesyl protein transferase (FPTase) bioassay system. During the course of activity-guided fractionation, the known lupane-type triterpenes, ochraceolide A (1), ochraceolide B (2), betulin, and lupeol and the new lupane lactone, dihydro ochraceolide A (4), were isolated. The stereochemistry of the epoxide group of ochraceolide B (2) was determined by preparation of both epoxide isomers [2, and the new semisynthetic derivative, 20-epi-ochraceolide B (3)] from 1. The structure of 4 was established by reduction of 1 with sodium borohydride. Compounds 1 and 2 exhibited significant inhibitory activity in the FPTase assay (IC50 values of 1.0 and 0.7 microgram/mL, respectively). Lupeol was found to be weakly active (IC50 65.0 micrograms/mL) in this test system, whereas no significant inhibition was detected for betulin or compounds 3 or 4. When evaluated against a panel of human cancer cells in culture, compounds 1 and 4 were modestly cytotoxic. Compounds 2 and 3 were not active in the panel.

Fission yeast Rep2 is a putative transcriptional activator subunit for the cell cycle ‘start’ function of Res2-Cdc10

In the yeast cell cycle 'start' requires sets of the Cdc10/ SWI family of transcriptional factors which activate the MCB cis elements contained in genes essential for S phase progression. Fission yeast possess two such overlapping systems, Res1-Cdc10 and Res2-Cdc10, both of which act to start the mitotic and meiotic cycles. We have recently isolated rep2+ as a multicopy suppressor of a temperature-sensitive cdc10 mutant which encodes a zinc finger protein. Here we show that the Rep2 zinc finger protein is an essential component of the active Res2-Cdc10 transcriptional regulator complex and likely to play a role in the control of cell cycle 'start'. Our data suggest that Rep2 is a transcriptional activator subunit which interacts with the MCB binding subunit complex formed by Res2 and Cdc10.

Expression of the Shigella dysenteriae type-1 lipopolysaccharide repeating unit in Escherichia coli K12/Shigella dysenteriae type-1 hybrids

The structures of the polysaccharide part of lipopolysaccharides isolated from eight Escherichia coli K12/Shigella dysenteriae type 1 hybrids have been determined using sugar and methylation analysis plus 1H- and 13C-nuclear magnetic resonance spectroscopy. The hybrids express parts of the S. dysenteriae type 1 O-antigen tetrasaccharide repeating unit because of the presence of pSS3, a plasmid expressing an alpha-galactosyl: lipopolysaccharide transferase and pSS9, a pBR322 plasmid expressing S. dysenteriae type 1 rfb genes. The various classes of hybrids are the result of transposon Tn 1000 insertions in pSS9 inactivating different rfb genes. The following structural elements were found. E. coli K12 (pSS3) and E. coli K12 (pSS3, pSS9-6; a class I hybrid); alpha-D-Galp(1-->3)beta-D-GlcpNAc(1-->. Class IV hybrids: E. coli K12 (pSS3, pSS9-36); (pSS3, pSS9-107) and (pSS3, pSS9-114); alpha-L-Rhap(1-->2)alpha-D-Galp(1-->3)beta-D-GlcpNAc(1-->. Class V hybrids: E. coli K12 (pSS3, pSS9-78) and (pSS3, pSS9-111); alpha-L-Rhap(1-->3)alpha-L-Rhap(1-->2)alpha-D-Galp(1-->3)bet a-D-GlcpNAc(1-->. The structural sequences are identical to those found in the lipopolysaccharide from native S. dysenteriae type 1. In the hybrid strains, the terminal non-reducing GlcNAc residue of the E. coli K12 core is fully substituted by S. dysenteriae type 1 repeating units, or parts thereof.

Detection of receptor-specific murine leukemia virus binding to cells by immunofluorescence analysis

Four classes of murine leukemia virus (MuLV) which display distinct cellular tropisms and bind to different retrovirus receptors to initiate virus infection have been described. In the present study, we describe a rapid, sensitive immunofluorescence assay useful for characterizing the initial binding of MuLV to cells. By using the rat monoclonal antibody 83A25 (L. H. Evans, R. P. Morrison, F. G. Malik, J. Portis, and W. J. Britt, J. Virol. 64:6176-6183, 1990), which recognizes an epitope of the envelope gp70 molecule common to the different classes of MuLV, it is possible to analyse the binding of ecotropic, amphotropic, or xenotropic MuLV by using only a single combination of primary and secondary antibodies. The MuLV binding detected by this assay is envelope receptor specific and matches the susceptibility to infection determined for cells from a variety of species. The binding of amphotropic MuLV to NIH 3T3 cells was shown to be rapid, saturable, and temperature dependent. Chinese hamster ovary (CHO-K1) cells normally lack the ability to bind ecotropic virus and are not infectible by ecotropic vectors. Expression of the cloned ecotropic retrovirus receptor gene (Rec) in CHO-K1 cells confers high levels of ecotropic virus-specific binding and confers susceptibility to infection. Characterization of MuLV binding to primary cells may provide insight into the infectibility of cells by retroviruses and aid in the selection of appropriate vectors for gene transfer experiments.

No retroviremia or pathology in long-term follow-up of monkeys exposed to a murine amphotropic retrovirus

Four monkeys were exposed to a retroviral vector and replication-competent murine amphotropic retrovirus in a bone marrow transplantation/gene transfer protocol (Kantoff et al., 1987). We have studied these animals 2 and 3 years post-transplantation and did not detect replicating virus in serum, peripheral blood mononuclear cells, or bone marrow cells. Amphotropic envelope sequences could not be detected in blood or bone marrow cells by Southern blotting or the polymerase chain reaction. Antibodies directed against the p30 and gp70 viral antigens were detected by Western blot and immunoprecipitation. The animals remain alive and well. Our findings suggest that primates can clear murine amphotropic retroviruses even when exposure occurs during a time of severe immunosuppression.

Amphotropic murine leukemia retrovirus is not an acute pathogen for primates

The in vivo fate of amphotropic murine leukemia retrovirus was studied in five rhesus monkeys. Retrovirus infused intravenously into 3 normal animals and 1 immunosuppressed animal was cleared rapidly from the circulation and subsequent viremia has not been detected (mean follow-up of 27.4 months). A fifth monkey was immunosuppressed and transplanted with virus-producing autologous fibroblasts in addition to an intraperitoneal injection of virus. This animal was viremic for 2 days and its lymph node cells and peripheral blood mononuclear cells were shown to be producing virus for up to 22 days post-inoculation, but subsequently has been negative after 17.0 months of analysis. In the 5 animals studied (combined mean follow-up of 25.7 months), clinical illness has not been identified at any time. Therefore, murine amphotropic retroviruses do not appear to pose an acute health risk.

Cloning of the rfb gene region of Shigella dysenteriae 1 and construction of an rfb-rfp gene cassette for the development of lipopolysaccharide-based live anti-dysentery vaccines

Recent studies have shown that determinants for the production of O antigen lipopolysaccharide in Shigella dysenteriae 1 are distributed over two distinct genetic elements, the chromosome and a 9 kb plasmid designated pHW400. In this communication, we describe the cloning of all determinants necessary for S. dysenteriae 1 O antigen production in E. coli K-12 and their combination in a single plasmid. An RP4::miniMu R-prime plasmid, R-prime 40, containing the his-rfb (histidine biosynthesis-lipopolysaccharide biosynthesis) gene region of the Shigella dysenteriae 1 chromosome was generated. E. coli K-12 bacteria containing R-prime 40 and pSS8, a transposon Tn5-tagged derivative of pHW400, produced lipopolysaccharide indistinguishable from that of S. dysenteriae 1. Small DNA fragments containing the rfb gene cluster and the rfp gene were subcloned from R-prime 40 and pSS8 and subsequently combined in vector pACYC184 to produce pSS37. This latter plasmid when introduced by transformation into E. coli K-12 provoked the formation of S. dysenteriae 1 O-specific lipopolysaccharide, a feature that suggests it may be useful in the construction of LPS-based live vaccines against the Shiga bacillus.

Genetic and biochemical analysis of Shigella dysenteriae 1 O antigen polysaccharide biosynthesis in Escherichia coli K-12: 9 kb plasmid of S. dysenteriae 1 determines addition of a galactose residue to the lipopolysaccharide core

Production of the somatic antigen, O-specific polysaccharide of Shigella dysenteriae 1 is determined by the chromosomal rfb gene cluster and the rfp gene located on the 9 kb plasmid pHW400 carried by this organism. When transferred to Escherichia coli K-12, which produces lipopolysaccharide consisting only of core oligosaccharide linked to lipid A, rfp gene-containing plasmids caused modification of the core oligosaccharide leading to the appearance of core molecules with new electrophoretic mobilities. Chemical analysis of the modified core has shown that it is substituted with a galactose residue which is the first sugar of the O-polysaccharide repeat unit.

Genetic and biochemical analysis of Shigella dysenteriae 1 O antigen polysaccharide biosynthesis in Escherichia coli K-12: structure and functions of the rfb gene cluster

The genetic organization and functions of the Shigella dysenteriae 1 rfb gene cluster, which specifies the somatic O antigen in this organism, have been studied in Escherichia coli K-12 by insertion and deletion mutagenesis of pSS9, a pBR322 hybrid containing the Shigella rfb genes. On the basis of the sensitivity/resistance to rough-specific bacteriophage T3 of E. coli K-12 derivatives containing mutant pSS9 plasmids, of the banding patterns and immunoreactivity of LPS isolated from such derivatives and electrophoresed on SDS-polyacrylamide gels, and of the sugar composition of the polysaccharide portion of the LPS determined by chemical analysis, six determinants for O antigen production were identified and localized. At least two determinants are involved in synthesis of TDP-rhamnose and the transfer of a rhamnose residue to the galactose-substituted core. One of these functions is probably TDP-rhamnose synthetase. A third function effects the transfer of a second rhamnose residue to the rha----gal-substituted core. A fourth function, for which evidence was obtained for two determinants (cistrons), is N-acetylglucosamine transferase, whereas a sixth determinant is necessary for extension of the first completed side chain repeat unit to the full O antigen polymer. These results confirmed the previously-determined chemical composition of the S. dysenteriae 1 O antigen and demonstrated that the order of the sugars is glcNAc----rha----rha----gal with gal as the first sugar linked to the core. Evidence was obtained for at least two transcriptional units in the rfb gene cluster and the approximate locations of two promoters are suggested. The detection of new electrophoretic species of LPS that may correspond to LPS biosynthetic intermediates, and the finding on the cell surfaces of structures corresponding to LPS core substituted with one or more O-specific sugars, appear to be novel findings.

Immunoblotting procedure for the analysis of electrophoretically-fractionated bacterial lipopolysaccharide

A procedure is described for the efficient transfer of fractionated bacterial lipopolysaccharide (LPS) from SDS-polyacrylamide gels to nitrocellulose filters, and its subsequent display by a peroxidase-linked antibody. The method is sensitive, and reveals and resolves high molecular weight LPS molecules having side chain lengths of up to and greater than 30 repeat units. It is useful for the rapid analysis of LPS in bacterial outer membrane preparations.

The relationship between t and H-2 complexes in wild mice. I. The H-2 haplotypes of 20 t-bearing strains

Twenty t haplotypes were extracted from wild mice captured at several locations in Europe, Israel, North Africa, and South America. The haplotypes were designated tTuw1 through tTuw20. The H-2 haplotypes of the lines were defined using antisera and monoclonal antibodies specific for private antigenic determinants controlled by known H-2 alleles and by antisera produced using the new t lines as donors. The tTuw haplotypes fall into four groups according to the H-2 haplotype associated with them. Haplotypes tTuw10 through tTuw18 are associated with H-2W30, previously found to be linked with haplotypes of the tw1 group. Haplotypes tTuw1 through tTuw6 are associated with a new H-2 haplotype, H-2w36, characterized by the determinant H-2.107. Haplotypes tTuw7 through tTuw9 are associated with another new H-2 haplotype, H-2w37, characterized by determinants H-2.108 and H-2.111. And finally, haplotypes tTuw19 and tTuw20 are associated with yet another new H-2 haplotype, H-2w38, characterized by determinants H-2.33 and H-2.109. These findings suggest that the t polymorphism might be more extensive and more intricate than it was previously thought to be and that at least some of the t-associated H-2 haplotypes, and probably also the t haplotypes themselves, are related to one another in their origin.