Expression and antibody inhibition of P-type calcium channels in human small-cell lung carcinoma cells

P-type channels, a recently described form of voltage-gated calcium channels, are found in many central and peripheral neurons. In the present study, a partial cDNA clone sharing extensive nucleotide identity with a putative P-type voltage-gated calcium channel alpha 1 subunit was isolated from a small-cell lung carcinoma (SCLC) cell line. Anti-peptide antibodies generated to a unique acidic stretch in the IVS5-S6 linker region of the putative SCLC P-type channel reacted specifically with a SCLC fusion protein produced in bacteria and with a cell surface molecule in SCLC cells. Calcium currents in SCLC cells, measured by whole-cell patch clamp, were inhibited by these antibodies and by the P-type channel-specific toxin omega-agatoxin IVA. The inhibitory effects of the antibody and the toxin were not additive, consistent with their proposed action on the same type of channel. These results provide evidence for the expression of P-type calcium channels by SCLC cells. The expression of neuron-related molecules by these cells is of particular interest because small-cell lung carcinoma is frequently associated with paraneoplastic disorders affecting the nervous system

Lambert-Eaton syndrome antibodies inhibit acetylcholine release and P/Q-type Ca2+ channels in electric ray nerve endings

The types of voltage-dependent calcium channels (VDCCs) present in the cholinergic terminals isolated from the electric organ of the ray, Narke japonica, were characterized on the basis of their pharmacological sensitivity to specific antagonists. Inhibition of these channel types by autoantibodies from patients with the Lambert-Eaton syndrome (LES) was then studied to determine the specificity of the pathogenic IgG. In normal untreated synaptosomal preparations, maximal doses of N- and P and/or Q-type Ca2+ channel antagonists, -conotoxin GVIA and -agatoxin IVA, inhibited depolarization-evoked ACh release by 47 % and 43 %, respectively. Calciseptine, an L-type VDCC antagonist, caused a 20 % reduction in the release. This indicates that the exocytotic release process is predominantly mediated by N- and P/Q-type VDCCs. LES IgG or sera caused an inhibition of ACh release by 39-45 % in comparison with the control antibody-treated preparations. The ionomycin-induced ACh release, however, was not altered by the antibodies. Additionally, the same LES antibodies inhibited whole-cell calcium currents (ICa) in bovine adrenal chromaffin cells. Thus, the pathogenic antibodies exert their action on VDCCs present in the synaptosomes. The efficacy of three Ca2+ channel antagonists in blocking ACh release was determined in preparations pretreated with LES IgG. -Agatoxin IVA produced only an additional 3-5 % reduction in release beyond that obtained with LES antibodies. Despite the pretreatment with LES IgG, -conotoxin GVIA and calciseptine inhibited the release to nearly their control levels. These results indicate that LES antibodies mainly downregulate P/Q-type Ca2+ channels which contribute to presynaptic transmitter release from the cholinergic nerve terminals of electric organ. The present findings are consistent with the hypothesis that P/Q-type VDCCs at the neuromuscular junction are the target of LES antibodies and that their inhibition by the antibodies produces the characteristic neuromuscular defect in this disease

Challenges of operational river forecasting

Skillful and timely streamflow forecasts are critically important to water managers and emergency protection services. To provide these forecasts, hydrologists must predict the behavior of complex coupled human–natural systems using incomplete and uncertain information and imperfect models. Moreover, operational predictions often integrate anecdotal information and unmodeled factors. Forecasting agencies face four key challenges: 1) making the most of available data, 2) making accurate predictions using models, 3) turning hydrometeorological forecasts into effective warnings, and 4) administering an operational service. Each challenge presents a variety of research opportunities, including the development of automated quality-control algorithms for the myriad of data used in operational streamflow forecasts, data assimilation, and ensemble forecasting techniques that allow for forecaster input, methods for using human-generated weather forecasts quantitatively, and quantification of human interference in the hydrologic cycle. Furthermore, much can be done to improve the communication of probabilistic forecasts and to design a forecasting paradigm that effectively combines increasingly sophisticated forecasting technology with subjective forecaster expertise. These areas are described in detail to share a real-world perspective and focus for ongoing research endeavors

Twenty-three unsolved problems in hydrology (UPH) – a community perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come

Lambert-Eaton syndrome antibodies inhibit acetylcholine release and P/Q-type Ca2+ channels in electric ray nerve endings

The types of voltage-dependent calcium channels (VDCCs) present in the cholinergic terminals isolated from the electric organ of the ray, Narke japonica, were characterized on the basis of their pharmacological sensitivity to specific antagonists. Inhibition of these channel types by autoantibodies from patients with the Lambert-Eaton syndrome (LES) was then studied to determine the specificity of the pathogenic IgG.In normal untreated synaptosomal preparations, maximal doses of N- and P and/or Q-type Ca2+ channel antagonists, ω-conotoxin GVIA and ω-agatoxin IVA, inhibited depolarization-evoked ACh release by 47% and 43%, respectively. Calciseptine, an L-type VDCC antagonist, caused a 20% reduction in the release. This indicates that the exocytotic release process is predominantly mediated by N- and P/Q-type VDCCs.LES IgG or sera caused an inhibition of ACh release by 39-45% in comparison with the control antibody-treated preparations. The ionomycin-induced ACh release, however, was not altered by the antibodies. Additionally, the same LES antibodies inhibited whole-cell calcium currents (ICa) in bovine adrenal chromaffin cells. Thus, the pathogenic antibodies exert their action on VDCCs present in the synaptosomes.The efficacy of three Ca2+ channel antagonists in blocking ACh release was determined in preparations pretreated with LES IgG. ω-Agatoxin IVA produced only an additional 3-5% reduction in release beyond that obtained with LES antibodies. Despite the pretreatment with LES IgG, ω-conotoxin GVIA and calciseptine inhibited the release to nearly their control levels.These results indicate that LES antibodies mainly downregulate P/Q-type Ca2+ channels which contribute to presynaptic transmitter release from the cholinergic nerve terminals of electric organ.The present findings are consistent with the hypothesis that P/Q-type VDCCs at the neuromuscular junction are the target of LES antibodies and that their inhibition by the antibodies produces the characteristic neuromuscular defect in this disease

Current European flood-rich period exceptional compared with past 500 years

There are concerns that recent climate change is altering the frequency and magnitude of river floods in an unprecedented way1. Historical studies have identified flood-rich periods in the past half millennium in various regions of Europe2. However, because of the low temporal resolution of existing datasets and the relatively low number of series, it has remained unclear whether Europe is currently in a flood-rich period from a long-term perspective. Here we analyse how recent decades compare with the flood history of Europe, using a new database composed of more than 100 high-resolution (sub-annual) historical flood series based on documentary evidence covering all major regions of Europe. We show that the past three decades were among the most flood-rich periods in Europe in the past 500 years, and that this period differs from other flood-rich periods in terms of its extent, air temperatures and flood seasonality. We identified nine flood-rich periods and associated regions. Among the periods richest in floods are 1560-1580 (western and central Europe), 1760-1800 (most of Europe), 1840-1870 (western and southern Europe) and 1990-2016 (western and central Europe). In most parts of Europe, previous flood-rich periods occurred during cooler-than-usual phases, but the current flood-rich period has been much warmer. Flood seasonality is also more pronounced in the recent period. For example, during previous flood and interflood periods, 41 per cent and 42 per cent of central European floods occurred in summer, respectively, compared with 55 per cent of floods in the recent period. The exceptional nature of the present-day flood-rich period calls for process-based tools for flood-risk assessment that capture the physical mechanisms involved, and management strategies that can incorporate the recent changes in risk.Europäischer Forschungsrat (ERC)Fonds zur Förderung der wissenschaftlichen Forschung (FWF)Fonds zur Förderung der wissenschaftlichen Forschung (FWF)5605667Horizon 2020DFGSpanish Agency of ScienceSpanish Agency of ScienceSpanish Agency of ScienceSpanish Agency of ScienceMinistry of Education, Youth and Sports of the Czech Republi