Nestmate recognition in a stingless bee: does the similarity of chemical cues determine guard acceptance?

The ability to discriminate nestmates from non-nestmates is critical to the maintenance of the integrity of social insect colonies. Guard workers compare the chemical cues of an incoming individual with their internal template to determine whether the entrant belongs to their colony. In contrast to honeybees, Apis mellifera, stingless bees have singly mated queens and, therefore, are expected to have a higher chemical homogeneity in their colonies. We tested whether aggressive behaviour of Frieseomelitta varia guards towards nestmate and non-nestmate foragers reflects chemical similarities and dissimilarities, respectively, of cuticular hydrocarbon profiles. We also introduced individuals of Lestrimelitta limao, an obligatory robber species, to test the ability of guards to react effectively to intruders from other taxa. We verified that foraging nestmates were almost invariably accepted, while heterospecific and conspecific non-nestmates were rejected at relatively high rates. However, non-nestmate individuals with higher chemical profile similarity were likely to be accepted by guards. We conclude that guards compare the chemical cuticular blend of incoming individuals and make acceptance decisions according to the similarity of the compounds between the colonies. (c) 2007 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Lobbying as a Guard against Extremism

This paper analyzes endogenous lobbying over a unidimensional policy issue. Individuals differ in policy preferences and decide either to join one of two opposite interest lobbies or not to take part in lobbying activities. Once formed, lobbies make contributions to the incumbent government in exchange for a policy favor as in a common-agency model. An equilibrium occurs only if no lobby member would prefer his lobby to cease to exist. I show the existence of an equilibrium with two organized lobbies. Individuals with more extreme preferences are more likely to join lobbying activities. Therefore, the lobbyists are rather extremists than moderates. However, the competition between those extreme lobbies results in a more moderate policy outcome relative to that initially preferred by the pro- or anti-policy government. Lobbies therefore guard against extremism, while acting as moderators of the government's preferences. JEL classification: D72. Keywords: common agency; endogenous lobbying; extremism.

Guard cell-specific calcium sensitivity of high density and activity SV/TPC1 channels.

The slow vacuolar (SV) channel, a Ca2+-regulated vacuolar cation conductance channel, in Arabidopsis thaliana is encoded by the single-copy gene AtTPC1. Although loss-of-function tpc1 mutants were reported to exhibit a stoma phenotype, knowledge about the underlying guard cell-specific features of SV/TPC1 channels is still lacking. Here we demonstrate that TPC1 transcripts and SV current density in guard cells were much more pronounced than in mesophyll cells. Furthermore, the SV channel in motor cells exhibited a higher cytosolic Ca2+ sensitivity than in mesophyll cells. These distinct features of the guard cell SV channel therefore probably account for the published stomatal phenotype of tpc1-2.

The Role of AtPHO1 in the Guard Cell Movements of Arabidopsis thaliana

In plants, stomatal opening and closing are driven by ion fluxes that cause changes in guard cell turgor and volume, a process that is in turn regulated by complex environ¬mental and hormonal signals such as light and the phytohormone abscisic acid (ABA). With this study, we present genetic evidence that stomatal movements in response to ABA are influenced by PHOl expression in guard cells of Arabidopsis thaliana. PHOl is a phosphate exporter involved in phosphate loading into the root xylem ves¬sels and, as a result, the phol mutant is characterized by low shoot phosphate lev¬els. In leaves, PHOl was found expressed at higher level in guard cells, and was quickly up-regulated following treatment with ABA. The phol mutant was unaffected in ROS production following ABA treatment, and in stomatal movements in response to different light cues, high extracellular calcium, auxin, and fusicoccin. However, stomatal movements in response to ABA treatment were severely impaired, both in terms of induction of closure and inhibition of opening. Stomatal movements in re¬sponse to hydrogen peroxide and reduced CO2 was altered as well. Micro-grafting a phol shoot scion onto wild-type root stock resulted in plants with normal shoot growth and Pi content, but failed to restore normal stomatal response to ABA treat-ment, showing that the impairment was not a simple pleiotropic consequence of phos¬phate deficiency. PHOl knockdown using RNAi specifically in guard cells of wild-type plants caused a reduced stomatal response to ABA. In agreement, specific expression of PHOl in guard cells of phol plants complemented the mutant guard cell phenotype and re-established ABA sensitivity, although full functional complementation was co- dependent on shoot Pi sufficiency. Down-regulation of PHOl in guard cells did not alter the expression of ABA marker genes, indicating that PHOl does not affect the ABA signal transduction cascade at the transcriptional level. Together, these data reveal an important role for phosphate and PHOl action in the stomatal response to ABA. Résumé L'ouverture et la fermeture des stomates des plantes sont des mouvements contrôlés par des flux d'ions causant des fluctuations de la turgescence des cellules de garde. Ce procédé est en retour régulé par des signaux environnementaux et hormonaux complexes, comme la lumière et l'hormone végétale acide abscissique (ABA). Nous présentons ici des preuves génétiques montrant que les mouvements stomatiques en réponse à l'ABA sont influencés par l'expression de PHOl dans les cellules de garde d'Arabidopsis thaliana. PHOl est un exporteur de phosphate, impliqué dans l'efflux de phosphate des cellules corticales racinaires vers les vaisseaux de xylème. En con¬séquence, le mutant phol est caractérisé par de faibles niveaux de phosphate dans les parties aériennes. Dans les feuilles, PHOl est exprimé préférentiellement dans les cellules de garde, comparé au mésophylle, et est rapidement induit par le traitement à l'ABA. Le mutant phol n'est pas affecté dans la perception de l'ABA, dans la pro¬duction de ROS en réponse à l'ABA, et dans la réponse des stomates aux traitements de lumière, à l'auxine, à la fusiccocine, et la forte concentration extracellulaire de cal¬cium. En revanche, les mouvements de stomates en réponse aux traitements à l'ABA sont fortement affectés, dans l'induction de la fermeture des stomates comme dans l'inhibition de leur ouverture. De plus, les mouvements de stomates en réponse au péroxyde d'hydrogène et à la diminution du CO2 sont aussi compromis. La création de micro-greffes composées d'une partie aérienne phol greffés sur un système racinaire sauvage génère des plantes avec une croissance et une teneur en phosphate normale, mais ne permet pas de restaurer la réponse des stomates à l'ABA, ce qui démontre que le défaut de réponse à l'ABA n'est pas une simple conséquence pléiotropique de la carence en phosphate. La répression par RNAi de l'expression de PHOl dans les stomates de plantes sauvages provoque une réduction de la réponse des stomates à l'ABA, mais n'affecte pas la réponse de gènes marqueurs à l'ABA, ce qui suggère que PHOl n'agit pas au niveau transcriptionnel. Parallèlement, l'expression de PHOl dans les cellules de gardes de mutants phol complémente le phénotype stomatique mutant et rétablit la réponse à l'ABA, bien que la totale complémentation nécessite l'apport normal de phosphate aux parties aériennes. Ensemble, ces résultats révè¬lent l'influence importante de PHOl et du phosphate dans la réponse des stomates à l'ABA.

Consumer Advisory Bulletin, Guard Your Bank Accounts!, June 2005

The Attorney General’s Consumer Protection Division receives hundreds of calls and consumer complaints every year. Follow these tips to avoid unexpected expense and disappointments. This record is about: Guard Your Bank Accounts!

Iowa National Guard Office of the Adjutant General Strategic Plan, 2008

This report outlines the strategic plan for Iowa National Guard Office of the Adjutant General, goals and mission.

Iowa National Guard Office of the Adjutant General Strategic Plan, 2010-2015

This report outlines the strategic plan for Iowa National Guard Office of the Adjutant General, goals and mission.

Iowa National Guard, Strategic Plan, 2010-2015

This report outlines the strategic plan for Iowa National Guard, goals and mission.

Carles Ros i Hebrera. Col·loqui nou, graciós i entretengut, on se referixen les festes celebrades en la ciutat de València a la proclamació de son rei i senyor nòstron Fernando Sext, que Déu guard, en los dies 19, 20 i 21 d'agost del present any 1746 : Edició crítica i estudi

En aquest treball es presenta una edició crítica del col·loqui sobre la proclamació del rei Ferran VI. També s'explica la relació dels col·loquis i el teatre breu, temes, llocs de representació, destinatari final i la funció dels seus creadors i recitadors anomenats col·loquiers. A més, s'explica el context sociopolític en què es varen concebre i unes pinzellades sobre el seu autor i la seua producció literària en català.

The Van-Guard (poem)

A poem "written at the front in memory of comrades fallen in action while fighting with the First Battalion of the 5th Field Artillery". The final verse of the poem reads, "But the van-guard on before you, who you follow as is meet, They're the lads you left behind you With the poppies and the wheat!"

Photograph - Governor General's Body Guard at Camp Niagara

Black and white photograph, mounted on board, 18 ½ cm. x 23 ½ cm. of the G.G.B.G. [Governor General’s Body Guard] on horseback at Camp Niagara.

Photograph - B Squadron of the G.G.B.G. [Governor General’s Body Guard] at Niagara

Black and white photograph, mounted on board, 13 cm x 20 cm of the B Squadron of the G.G.B.G. [Governor General’s Body Guard] at Niagara.

Chart of bill of timber in bridges, culverts, cattle-guard and roadways, signed by S.D. Woodruff

Chart of bill of timber in bridges, culverts, cattle-guard and roadways, signed by S.D. Woodruff, Oct. 18, 1855.