Cretaceous Therian Tarsals and the Metatherian-Eutherian Dichotomy

Diverse metatherian and eutherian tarsal remains from the Late Cretaceous (middle-late Turonian) Bissekty Formation, Kyzylkum Desert, Uzbekistan (ca 90 MYA) are described. Their functional and taxonomic properties, along with those of other tarsal evidence, led to a reassessment of polarity hypotheses of therian, metatherian, and eutherian cruropedal attributes, and the consequences of this for phylogeny of taxa. There are calcaneal remains of several types of marsupials, and a single astragalus that probably belongs to one of these. This represents greater taxonomic diversity than the dental record suggests. Exceptionally large and distally extending peroneal processes, and small and steeply angled calcaneocuboid articulations facing mediodistally, as seen in the Early Cretaceous Sinodelphys and other Cretaceous and Paleogene taxa, attest not only to the metatherian status of these specimens, but also to the retention of many ancestral therian features, even more so than in both the Tiupampa and Itaboraí marsupials of the South American Paleocene (both the calcanea and the astragalus suggest therian traits that are decidedly unlike those of symmetrodonts). Calcanea allocated to the deltatherioid species at Bissekty testify unequivocally to their metatherian affinity. The morphology of the best represented sample of eutherian calcanea from Bissekty, presumably of a number of zhelestid species, appears to be more derived than that of the Late Cretaceous/Paleocene Protungulatum in having a much more reduced peroneal process and a calcaneocuboid articulation that faces distally, oriented nearly at a 90° angle to the long axis of the calcaneus. In fact, this distally facing facet, common in later eutherians (except for lineages in the Paleogene record, and various Carnivora), may not be diagnostic of either the protoeutherian, or even of the protoplacentalian, in spite of its presence in Eomaia. Many putatively “basal” lineages have derived characters, hence such outgroups should not be considered the unequivocal repositories of only ancestral character states.     

3-[18F]Acetylcyclofoxy: a useful probe for the visualization of opiate receptors in living animals

A fluoro-analogue of the potent narcotic antagonist, naltrexone, was synthesized and shown to bind with high affinity to opiate receptors in vitro. 3-[18F]acetylcyclofoxy was prepared via a one-step triflate displacement reaction with the positron emitting 18F ion from tetraethylammonium [18F] fluoride. 3-[18F]acetylcyclofoxy accumulation in opiate receptor rich brain regions of both rat and baboon is shown to be completely displaced by the active enantiomer of naloxone [-)-naloxone) while the identical dose of the pharmacologically inert (+)-naloxone has no detectable effect. Moreover, both rat and baboon brain showed the well documented, typical opiate receptor distribution so that basal ganglia and thalamus are clearly visible in the living baboon brain up to 95 min after intravenous injection of 3-[18F] acetylcyclofoxy. We expect that 3-[18F )acetylcyclofoxy will be a useful probe for visualizing opiate receptors in living humans.     

Copolymerization of lobster lactate dehydrogenase isoenzymes with pig H4 isoenzyme in vitro

The simple isoenzymatic pattern for LDH in Crustacea and their restrictive ability to copolymerize with mammal isoenzymes indicate early divergence and different evolutionary pressure with respect to control of the catalytic activity.     

Volatile components of lemur scent secretions vary throughout the year

Olfactory signals can communicate a wide variety of information and are very important in many mammalian species. However, little is known about the olfactory communication of primates. This study used gas chromatography to examine the volatile components of the anogenital gland secretions of wild Milne-Edward's sifaka, Propithecus edwardsi (Primates, Indriidae) (n = 17), captured in Ranomafana National Park, Madagascar. We compared scent swabs of animals and examined differences between social group, age class, sex, and season. The only identified differences in the volatiles were between swabs from the different seasons; all other categories were statistically indistinguishable.     

新型抗肺癌转移药系列化合物的合成

本文以对氨基苯甲酸为原料,经过重氮化、偶合、成盐等反应,合成4个抗肺癌转移药,并作了红外鉴定。     

Relationship between cytotoxicity and induction of sister-chromatid exchanges in mouse foetal cells exposed to several doses of carcinogenic and non-carcinogenic chemicals.

The increase in sister-chromatid exchanges induced by 5 chemicals, with different DNA damaging and carcinogenic activities, was studied in short-term foetal-mouse cultures. A significant increase in SCE was induced by N-methyl-N'-nitro-N-nitrosoguanidine, N-diazoacetylglycine-amide, azaserine and methotrexate. k-Strophantin, on the contrary, was totally inactive. On a molar basis, MNNG was the most active chemical followed by MTX, AZS and DGA, in that order. At equitoxic concentrations (D37), the order of SCE-inducing abilities was MNNG, DGA, AZS and MTX. Compared with previous data, at equitoxic concentrations, the most DNA-damaging agents were also the most effective in inducing SCE. The SCE increase seems to correlate not with unspecific cytotoxicity but more with DNA damage or other damage at the genome level. MTX, a non-mutagen, which induced SCE only at toxic levels, could be considered a false positive because this positivity may reflect an enhancement of incorporation of 5-BrdUrd into DNA. The positive results obtained with AZS suggest a sufficient sensitivity of the method for detecting relatively weak carcinogens.     

Morphogenetic interactions occurring between blastemas and stumps after exchanging blastemas between normal and double-half forelimbs in the axolotl, Ambystoma mexicanum.

Regeneration blastemas were exchanged between surgically constructed forelimbs comprised of symmetrical tissues (double-anterior and double-posterior) and normal, unoperated forelimbs. Normal blastemas grafted at the stage of medium bud (MB) onto double-half forelimb stumps regenerated normal skeletal patterns in nearly all cases. Double-half blastemas transplanted at the stage of MB onto normal forelimb stumps did not regenerate complete limb patterns. These results indicate that a double-half blastema cannot be “rescued” by transplantation to a normal stump and that a double-half limb stump does not interfere with the ability of a normal blastema to distally transform. The regeneration blastema possesses sufficient positional information at the stage of MB to permit it to develop autonomously. Supernumerary forelimbs resulted from several types of graft-stump combinations. The location and handedness of these supernumerary limbs are predicted by the rules of a recently presented model for pattern regulation in epimorphic fields [French, V., Bryant, P. J., and Bryant, S. V. (1976). Science193, 969–981].