Labdane and dehydronerolidol derivatives from Brickellia diffusa

An investigation of Brickellia diffusa afforded three new dehydronerolidol derivatives and five new labdane derivatives, all highly oxygenated. The structures were elucidated by spectroscopic methods and a few chemical transformations. The compounds isolated showed close relationships to those isolated from Brickellia sp.     

A dimeric germacranolide and other sesquiterpene lactones from Mikania species

The investigation of two Mikania species, both previously placed in the genus Kanimia, afforded in addition to known compounds several new germ     

Four guaianolides,a eudesmanolide and a germacranolide from Ursinia saxatilis

An investigation of Ursinia saxatilis afforded in addition to known compounds a new eudesmanolide derived from ursialpinolide, a germacranolide rel     

Types of sesquiterpenes from Artemisia douglasiana

Artemisia douglasiana afforded, in addition to known compounds, two new C₁₄-acetylenes, five longipinene derivatives, three nerolidol derivatives, a lactone and a ketone with a new carbon skeleton and lavendulol-2-methylbutyrate. The structures were elucidated by spectroscopic methods and some chemical transformations. The configurations of several oxo longipinene-7, 9-di- and 7, 8, 9-triesters isolated previously were corrected. The biogenesis of the new lactones is discussed briefly.     

Cellular proliferation kinetics of the murine sarcoma induced by the Moloney sarcoma virus

Abstract. Cell proliferation kinetics of the sarcoma induced by Moloney virus was studied in newborn Swiss OFl mice.
After in vivo injection of tritiated thymidine, followed by autoradiography, it was shown that the majority of cells were actively proliferating (labelling index; 31%, growth fraction 78%). The mean cell cycle was 16 hr and cell loss was relatively low (cell loss factor 48%). The study of tumour specific activity with time after a single [ in vivo ] injection of [³H]dR or [¹²⁵I]UdR did not demonstrate the same degree of cell loss as that calculated by autoradiography. This result is consistent with a massive reutilization of radioactivity released by normal tissues.     

Inheritance of susceptibility to the myeloproliferative sarcoma virus: effect of the Fv-2 locus and evidence for a myeloproliferative sarcoma virus resistance locus.

Myeloproliferative sarcoma virus (MPSV) causes a generalized stem cell leukemia with erythroid and myeloid hyperplasia in adult mice. MPSV also transforms fibroblasts. Mice congenic for the Fv-2 locus showed marked differences in susceptibility to MPSV according to the Fv-2 genotype. MPSV was injected into C57BL/6 Fvs and C57BL/6 Fv-2r mice congenic except for the Fv-2 locus. C57BL/6 mice with the Fvs genotype were much more susceptible to MPSV than were those with the Fvr genotype. Both DDD Fv-2r mice congenic with DDD Fv-2s mice except for the Fv-2 locus and DDD Fv-2s mice, however, were sensitive to spleen focus formation by MPSV. These data indicate that at least one additional resistance locus to MPSV is present in C57BL/6 mice but not in DDD mice. Both the Fv-2 locus and the putative MSPV resistance locus (loci) Mpsvr appear to be epistatic to either of the sensitivity loci. Fibroblast focus formation by MPSV was obtained well in C57BL/6 Fv-2r and C57BL/6 Fvs fibroblasts, indicating that the genes for MPSV resistance (Fv-2r and Mpsvr) were not operating in fibroblast cells. A model is proposed which may account for the differences in response of genetically different mice to MPSV and Friend spleen focus-forming virus.     

Two sesquiterpene lactones with an additional propiolactone ring from Disynaphia halimifolia

The investigation of D. halimifolia afrorded a new glaucolide and two sesquiterpene lactones with an additional propiolactone ring, one elemanolide and one modified germacranolide with an additional ring. Furthermore, two tremetone derivatives were present, a hydroxy-geranylgeraniol, also present in a Kingianthus species, and several known compounds.     

Trixikingolides and germacrene derivatives from Trixis species

The investigation of two further Trixis species afforded five new sesquiterpenes related to trixikingolide, six new germacrene derivatives and a sesquiterpene derived from rotundene. Some further known compounds were isolated too, which in part may be of chemotaxonomic significance. The structures were elucidated by spectroscopic methods and a few chemical transformations. The relative position of the ester groups in eight of the new sesquiterpenoids however, could not be established with certainty as partial saponifications were not successful.     

Myeloproliferative virus, a cloned murine sarcoma virus with spleen focus-forming properties in adult mice.

Myeloproliferative virus, derived from Moloney sarcoma virus, causes erythroleukemia and myeloid leukemia in adult mice. This virus is also capable of fibroblast transformation in vitro. The virus consists of two separable biological entities which have been cloned. The helper virus component caused no visible changes in adult mice, whereas the defective virus induced both spleen focus formation and a large increase in erythroid precursor cells but retained the sarcoma virus property of transforming fibroblasts in vitro. Thus, myeloproliferative virus is the first murine sarcoma virus which induces erythroleukemia in adult animals.