TY  - JOUR
A1  - De Palma, Adriana
A1  - Abrahamczyk, Stefan
A1  - Aizen, Marcelo A.
A1  - Albrecht, Matthias
A1  - Basset, Yves
A1  - Bates, Adam
A1  - Blake, Robin J.
A1  - Boutin, Céline
A1  - Bugter, Rob
A1  - Connop, Stuart
A1  - Cruz-López, Leopoldo
A1  - Cunningham, Saul A.
A1  - Darvill, Ben
A1  - Diekötter, Tim
A1  - Dorn, Silvia
A1  - Downing, Nicola
A1  - Entling, Martin H.
A1  - Farwig, Nina
A1  - Felicioli, Antonio
A1  - Fonte, Steven J.
A1  - Fowler, Robert
A1  - Franzen, Markus Franzén
A1  - Goulson, Dave
A1  - Grass, Ingo
A1  - Hanley, Mick E.
A1  - Hendrix, Stephen D.
A1  - Herrmann, Farina
A1  - Herzog, Felix
A1  - Holzschuh, Andrea
A1  - Jauker, Birgit
A1  - Kessler, Michael
A1  - Knight, M. E.
A1  - Kruess, Andreas
A1  - Lavelle, Patrick
A1  - Le Féon, Violette
A1  - Lentini, Pia
A1  - Malone, Louise A.
A1  - Marshall, Jon
A1  - Martínez Pachón, Eliana
A1  - McFrederick, Quinn S.
A1  - Morales, Carolina L.
A1  - Mudri-Stojnic, Sonja
A1  - Nates-Parra, Guiomar
A1  - Nilsson, Sven G.
A1  - Öckinger, Erik
A1  - Osgathorpe, Lynne
A1  - Parra-H, Alejandro
A1  - Peres, Carlos A.
A1  - Persson, Anna S.
A1  - Petanidou, Theodora
A1  - Poveda, Katja
A1  - Power, Eileen F.
A1  - Quaranta, Marino
A1  - Quintero, Carolina
A1  - Rader, Romina
A1  - Richards, Miriam H.
A1  - Roulston, T’ai
A1  - Rousseau, Laurent
A1  - Sadler, Jonathan P.
A1  - Samnegård, Ulrika
A1  - Schellhorn, Nancy A.
A1  - Schüepp, Christof
A1  - Schweiger, Oliver
A1  - Smith-Pardo, Allan H.
A1  - Steffan-Dewenter, Ingolf
A1  - Stout, Jane C.
A1  - Tonietto, Rebecca K.
A1  - Tscharntke, Teja
A1  - Tylianakis, Jason M.
A1  - Verboven, Hans A. F.
A1  - Vergara, Carlos H.
A1  - Verhulst, Jort
A1  - Westphal, Catrin
A1  - Yoon, Hyung Joo
A1  - Purvis, Andy
T1  - Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases
JF  - Scientific Reports
N2  - Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises.
KW  - bee community
KW  - land-use change
KW  - intensification
KW  - geographic biases
KW  - taxonomic biases
KW  - global dataset
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167642
VL  - 6
ER  - 
TY  - JOUR
A1  - Parker, H. E.
A1  - Adriaenssens, A.
A1  - Rogers, G.
A1  - Richards, P.
A1  - Koepsell, H.
A1  - Reimann, F.
A1  - Gribble, F. M.
T1  - Predominant role of active versus facilitative glucose transport for glucagon-like peptide-1 secretion
JF  - Diabetologia
N2  - Aims/hypothesis
Several glucose-sensing pathways have been implicated in glucose-triggered secretion of glucagon-like peptide-1 (GLP-1) from intestinal L cells. One involves glucose metabolism and closure of ATP-sensitive K\(^+\) channels, and another exploits the electrogenic nature of Na\(^+\)-coupled glucose transporters (SGLTs). This study aimed to elucidate the role of these distinct mechanisms in glucose-stimulated GLP-1 secretion.

Methods
Glucose uptake into L cells (either GLUTag cells or cells in primary cultures, using a new transgenic mouse model combining proglucagon promoter-driven Cre recombinase with a ROSA26tdRFP reporter) was monitored with the FLII\(_{12}\)Pglu-700μδ6 glucose sensor. Effects of pharmacological and genetic interference with SGLT1 or facilitative glucose transport (GLUT) on intracellular glucose accumulation and metabolism (measured by NAD(P)H autofluorescence), cytosolic Ca\(^{2+}\) (monitored with Fura2) and GLP-1 secretion (assayed by ELISA) were assessed.

Results
L cell glucose uptake was dominated by GLUT-mediated transport, being abolished by phloretin but not phloridzin. NAD(P)H autofluorescence was glucose dependent and enhanced by a glucokinase activator. In GLUTag cells, but not primary L cells, phloretin partially impaired glucose-dependent secretion, and suppressed an amplifying effect of glucose under depolarising high K\(^+\) conditions. The key importance of SGLT1 in GLUTag and primary cells was evident from the impairment of secretion by phloridzin or Sglt1 knockdown and failure of glucose to trigger cytosolic Ca\(^{2+}\) elevation in primary L cells from Sglt1 knockout mice.

Conclusions/interpretation
SGLT1 acts as the luminal glucose sensor in L cells, but intracellular glucose concentrations are largely determined by GLUT activity. Although L cell glucose metabolism depends partially on glucokinase activity, this plays only a minor role in glucose-stimulated GLP-1 secretion.
KW  - KATP channel
KW  - glucokinase
KW  - glucagon-like peptide-1 (GLP-1)
KW  - SGLT1
KW  - L cells
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125927
VL  - 55
IS  - 9
ER  -