Slavery in the subfamily dolichoderinae (F. Formicidae) and its ecological consequences

Summary Evidence of slave-making habits in 2 species of the subfamily Dolichoderinae has been found in arid habitats of western North America. The enslaved species are of the subfamilies Myrmicinae and Formicinae. In previously reported cases of slavery in ants, both the slave-making and enslaved species are of the subfamily Formicinae., In the 2 new cases of slavery reported here, presence of slaves of another species in a colony significantly increases the breadth of diet and/or the range of temperatures at which the colony forages.     

Steroidal cyclic ketals: The preparation of steroidalΔ 4-3-ethyleneketals

Zusammenfassung Ersatz vonp-Toluolsulfosäure durch Oxal- oder, bevorzugt, Adipinsäure in Salmis Methode für die Synthese von ⁵-3-Äthylendioxysteroiden führt zu ⁴-3-Äthylendioxysteroiden.

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Paper XXIV; paper XXIII seeS. Bernstein andR. Littell, J. org. Chem.26, 3610 (1961).     

Über die Geruchsspur vonLasius fuliginosus zwischen Nest und Futterquelle

Summary In this study it was found that the chemical trail laid by workers of the ant speciesLasius fuliginosus between their nest and a food source, is always laid in the direction food to nest. It was also found that this trail can be artificially created by dissolving the contents of the ant's hind-gut or stomach in water, and then spreading the resulting fluid on paths leading away from the nest. This artificial trail is only effective when moist, but can be reactivated by placing water on the dried remains of the trail.     

Isolation of a cDNA encoding the vascular type-1 angiotensin II receptor

Angiotensin II is an important effector molecule controlling blood pressure and volume in the cardiovascular system. Its importance is manifested by the efficacy of angiotensin-converting enzyme inhibitors in the treatment of hypertension and congestive heart failure. Angiotensin II interacts with two pharmacologically distinct subtypes of cell-surface receptors, AT1 and AT2. AT1 receptors seem to mediate the major cardiovascular effects of angiotensin II. Here we report the isolation by expression cloning of a complementary DNA encoding a unique protein with the pharmacological specificity of a vascular AT1 receptor. Hydropathic modelling of the deduced protein suggests that it shares the seven-transmembrane-region motif with the G protein-coupled receptor superfamily. Knowledge of the AT1 receptor primary sequence should now permit structural analysis, definition of the angiotensin II receptor gene family and delineation of the contribution of AT receptors to the genetic component of hypertension.     

A conserved RNA-binding protein controls germline stem cells in Caenorhabditis elegans

Germline stem cells are defined by their unique ability to generate more of themselves as well as differentiated gametes. The molecular mechanisms controlling the decision between self-renewal and differentiation are central unsolved problems in developmental biology with potentially broad medical implications. In Caenorhabditis elegans, germline stem cells are controlled by the somatic distal tip cell. FBF-1 and FBF-2, two nearly identical proteins, which together are called FBF ('fem-3 mRNA binding factor'), were originally discovered as regulators of germline sex determination. Here we report that FBF also controls germline stem cells: in an fbf-1 fbf-2 double mutant, germline proliferation is initially normal, but stem cells are not maintained. We suggest that FBF controls germline stem cells, at least in part, by repressing gld-1, which itself promotes commitment to the meiotic cell cycle. FBF belongs to the PUF family ('Pumilio and FBF') of RNA-binding proteins. Pumilio controls germline stem cells in Drosophila females, and, in lower eukaryotes, PUF proteins promote continued mitoses. We suggest that regulation by PUF proteins may be an ancient and widespread mechanism for control of stem cells.     

Fv2 encodes a truncated form of the Stk receptor tyrosine kinase.

The Friend virus susceptibility 2 (Fv2) locus encodes a dominant host factor that confers susceptibility to Friend virus-induced erythroleukaemia in mice. We mapped Fv2 to a 1.0-Mb interval that also contained the gene (Ron) encoding the stem cell kinase receptor (Stk). A truncated form of Stk (Sf-stk), which was the most abundant form of Stk in Fv2-sensitive (Fv2ss) erythroid cells, was not expressed in Fv2 resistant (Fv2rr) cells. Enforced expression of Sf-stk conferred susceptibility to Friend disease, whereas targeted disruption of Ron caused resistance. We conclude that the Fv2 locus encodes Ron, and that a naturally expressed, truncated form of Stk confers susceptibility to Friend virus-induced erythroleukaemia.