Spacing and kinship in the Formosan squirrel living in different habitats

Summary Spacing and kinship of the Formosan squirrel, Callosciurus erythraeus thaiwanensis, were studied in two different habitats. One, native habitat in the woods of Kenting, southern Formosa, was rich in available food throughout the year and had several species of predators. The other, a site in Kamakura, central Japan where squirrels had been introduced, had relatively scanty food and few potential predators. 1. Home ranges among males and between sexes overlapped extensively in both habitats. 2. Females occupied exclusive home ranges in Kamakura but had small overlapping home ranges in Ken-ting. 3. Most males disappeared from their natal areas at 1 year old in both habitats (86% in Kamakura and 93% in Ken-ting), but less females disappeared (36% in Kamakura and 35% in Ken-ting). 4. In Kamakura, daughters settled adjacent to the mother or inherited the home range of the mother, but never shared the mother's home range. In Ken-ting, 35% of daughters shared the home range with their mothers. 5. Tolerance among female kin in Ken-ting was probably facilitated by the richness of available food throughout the year, and functioned to reduce predation risk via alarm calling and mobbing.     

Existence of a Common Glycoprotein Homologous to S-Glycoproteins in Two Self-incompatible Homozygotes of Brassica campestris

S-Glycoproteins (S-locus-specific glycoproteins) in Brassicaspecies are present only in stigmas and thought to play an importantrole in self-incompatibility system. The stigma extract containsalso several other glycoproteins reacting with the antiserumto S-glycoproteins, among which some glycoproteins from S₈S₈-and S₉S₉-homozygotes have the same pI value. Both of the glycoproteinswhich were tentatively termed NS₈- and NS₈S₉-glycoproteins,respectively, were isolated and analyzed. Those were revealedto be identical. Its amino acid sequence was homologous withthe S-glycoproteins in Brassica species. The NS-glycoproteinswere expressed at the same time and only in stigma as S-glycoproteins. (Received July 19, 1988; Accepted September 7, 1988)     

Analysis of the replication mode of double minutes using the PCC technique combined with BrdUrd labeling

A cultured line of neuroblastoma cells (NB) was found to contain double minute chromosomes (DMs). DMs have been reported to be acentric and, therefore, to be segregated randomly into daughter cells without separating their sister elements. When NB cells were fused with Chinese hamster metaphase cells, prematurely condensed chromosomes (PCCs) were induced. DMs seen together with G₂ PCCs appeared to be closely paired, dot-like structures resembling DMs observable in metaphase cells. In contrast, DMs in G₁ cells showed a tendency to become single as the stage progressed so that the majority of DMs in late G₁ cells were actually no longer double. DMs in S-phase cells, however, again appeared double. These results clearly indicate why DMs are invariably double and never assume a quadruple configuration in metaphase cells in spite of their non-disjunctional segregation at anaphase. Such a characteristic mode of DM replication was further confirmed by a 5-bromo-2-deoxyuridine (BrdUrd) labeling experiment: when NB cells were exposed to BrdUrd for two successive rounds of DNA replication prior to PCC induction, half of the resulting single G₁ minutes as well as G₁ PCCs stained dark and the other half stained light after staining for sister chromatid differentiation.     

High-order structure of metaphase chromosomes: evidence for a multiple coiling model

When chromosome preparations made by the conventional air-drying method were processed with the OsO₄/TCH technique and examined by scanning electron microscopy (SEM), spiral structures in chromatids, which have been frequently observed to be present by light microscopy, were found to be composed of 30 nm fibres. In some portions these fibres appeared to be arranged in coils to form thicker fibres. When chromosome preparations were processed for SEM without air drying, chromosomes appeared to consist of fairly homogeneous thick fibrous structures measuring about 200 nm in diameter. In relatively condensed chromosomes, these 200 nm fibres appeared to be arranged perpendicular to the long axis of the chromatid. These findings suggest that chromatid spiral structures represent a regularly loosened state of the compactly spiralized 200 nm fibres which in turn consist of spiralized 30 nm fibres.     

Activated c-raf gene in a rat hepatocellular carcinoma induced by 2-amino-3-methylimidazo[4,5-f]quinoline

A rat hepatocellular carcinoma, IQ7, induced by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) gave two transformants of NIH 3T3 cells on DNA mediated gene transfer. One of these transformants was examined further and secondary and tertiary transformants were obtained. The secondary transformant was tumorigenic in nude mice. The activated oncogene in this primary transformant was identified as rat c-raf by Southern blot analysis.     

Location of polar substituents and fatty acyl chains on lipid A precursors from a 3-deoxy-D-manno-octulosonic acid-deficient mutant of Salmonella typhimurium. Studies by 1H, 13C, and 31P nuclear magnetic resonance

Eight anionic disaccharide precursors of lipid A accumulate at 42 degrees C in 3-deoxy-D-manno-octulosonic acid-deficient temperature-sensitive mutants of Salmonella typhimurium. These compounds comprise a series of lipids based on the minimal structure, O-[2-amino-2-deoxy-N2,O3-bis(3-hydroxytetradecanoyl)-beta-D-glucopyranos yl] -(1----6)-2-amino-2-deoxy-N2, O3-bis(3-hydroxytetradecanoyl)-alpha-D-glucopyranose 1,4'- bisphosphate (designated lipid IVA) that differ from each other by the presence of an additional phosphoethanolamine moiety (IIIA), or an aminodeoxypentose moiety (IIA), or both (IA). A homologous set of metabolites is further derivatized with a palmitoyl function; these are designated IVB, IIIB, IIB, and IB (Raetz, C. R. H., Purcell, S., Meyer, M. V., Qureshi, N., and Takayama, K. (1985) J. Biol. Chem. 260, 16080-16088). The attachment of the palmitoyl moiety, known to be on the reducing terminal GlcN residue by mass spectrometry, was determined to be O-beta of the N2-linked beta-hydroxymyristoyl group of that residue of IVB by 13C NMR and two-dimensional 1H chemical shift correlation spectroscopy experiments. 31P NMR indicated the presence of diphosphodiester moieties in IIIA, IIIB, and IA and monophosphodiester moieties in IIA and IA. Selective 1H decoupling of the 31P spectrum of IIIA demonstrated that the O-diphosphoethanolamine moiety is attached to the O4' position in IIIA. On the basis of the observed 31P chemical shifts it was concluded that the aminodeoxypentose is located at position 1 in IIA and IA, while diphosphoethanolamine is most likely located at O-4' in IA and IIIB, as in IIIA.