Mechanisms of spacing in groups of juncos: Measurement of behavioural tendencies in social situations

To investigate behavioural mechanisms that regulate the spacing of individuals, we studied aggression, approach, and avoidance of captive male juncos (Junco hyemalis) in relation to the distance between individuals. We measured behavioural tendencies by analysing the terminations of social states so as to determine the instantaneous probability rates of terminal actions. These rates permit accurate comparisons of behavioural tendencies in different social situations. An individual's tendencies to supplant, approach, or withdraw from an opponent depended on the dominance relationship of the two birds and on the distance between them. Interactions did not vary with the magnitude of the difference between opponents' ranks. The dependence of aggression, approach, and avoidance on the distance between opponents controls the spacing of individuals.     

Induced recovery of a suppressed idiotype by immunization with anti-idiotype

Neonatal Balb/c mice were suppressed forthe H8/T15 idiotype by injection of homologous anti-H8 (D. S. Strayer, D. A. Rowley, and H. Köhler, et al J. Immunol.114, 722, 1975. Six to eight weeks later groups of these suppressed mice were immunized up to three times with isologous anti-H8 raised in Balb/c. After a rest of 4 weeks each group was challenged with R36a vaccine and bleedings were obtained before and after this challenge. All sera were assayed for total anti-PC and H8 idiotype amounts by solid-phase radioimmunoassay. After two-preimmunizations with isologous anti-H8 no increase of the H8 levels was observed though these mice responded to R36a immunization with an increase of total anti-PC antibodies. After the third preimmunization, however, the H8 idiotype was increased in sera taken before and after challenge with R36a. These findings demonstrate that the state of neonatal idiotype suppression can be broken by immunization with complementary anti-idiotype.     

PINEAL SEROTONIN N-ACETYLTRANSFERASE ACTIVITY: PROTECTION OF STIMULATED ACTIVITY BY ACETYL-CoA AND RELATED COMPOUNDS

—Rat pineal serotonin N—acetyltransferase activity increases 30–70-fold at night in the dark and then decreases rapidly when animals are exposed to light. Activity of the enzyme is also stimulated by l -norepinephrine in organ culture. When homogenates of glands stimulated by dark in vivo or NE in vitro are incubated at 37°C, enzyme activity will also rapidly decrease. This decrease can be prevented by one of the cosubstrates of the enzyme, acetyl–CoA. Protection can also be conferred by cysteamine (β-mercaptoethylamine, HS–CH₂–CH₂–NH₂) which is the terminal portion of the CoA molecule. This protection mechanism could be involved in the physiological control of enzyme activity.     

Control of the pericentrosomal H2O2 level by peroxiredoxin I is critical for mitotic progression

Proteins associated with the centrosome play key roles in mitotic progression in mammalian cells. The activity of Cdk1-opposing phosphatases at the centrosome must be inhibited during early mitosis to prevent premature dephosphorylation of Cdh1—an activator of the ubiquitin ligase anaphase-promoting complex/cyclosome—and the consequent premature degradation of mitotic activators. In this paper, we show that reversible oxidative inactivation of centrosome-bound protein phosphatases such as Cdc14B by H₂O₂ is likely responsible for this inhibition. The intracellular concentration of H₂O₂ increases as the cell cycle progresses. Whereas the centrosome is shielded from H₂O₂ through its association with the H₂O₂-eliminating enzyme peroxiredoxin I (PrxI) during interphase, the centrosome-associated PrxI is selectively inactivated through phosphorylation by Cdk1 during early mitosis, thereby exposing the centrosome to H₂O₂ and facilitating inactivation of centrosome-bound phosphatases. Dephosphorylation of PrxI by okadaic acid–sensitive phosphatases during late mitosis again shields the centrosome from H₂O₂ and thereby allows the reactivation of Cdk1-opposing phosphatases at the organelle.     

Predation by squirrel monkeys and double-toothed kites on tent-making bats

Central American squirrel monkeys (Saimiri oerstedi) appear to recognize the modified leaves that phyllostomid bats utilize for diurnal roost sites. The monkeys visually and manually search these bat tents for both bats and insects. Adult males are the most successful at capturing bats. Nonvolant juvenile bats are more vulnerable to monkey predation than are adults. Bats that escape monkey predation frequently are captured by doubletoothed kites (Harpagus bidentatus) that tend foraging troops of monkeys. Predation by squirrel monkeys, coupled with that of double-toothed kites, may be a significant source of mortality for tent-making bats.     

Uncovering the evolutionary origin of blue anthocyanins in cereal grains

Functional divergence after gene duplication plays a central role in plant evolution. Among cereals, only Hordeum vulgare (barley), Triticum aestivum (wheat) and Secale cereale (rye) accumulate delphinidin‐derived (blue) anthocyanins in the aleurone layer of grains, whereas Oryza sativa (rice), Zea mays (maize) and Sorghum bicolor (sorghum) do not. The underlying genetic basis for this natural occurrence remains elusive. Here, we mapped the barley Blx1 locus involved in blue aleurone to an approximately 1.13 Mb genetic interval on chromosome 4HL, thus identifying a trigenic cluster named MbHF35 (containing HvMYB4H, HvMYC4H and HvF35H). Sequence and expression data supported the role of these genes in conferring blue‐coloured (blue aleurone) grains. Synteny analyses across monocot species showed that MbHF35 has only evolved within distinct Triticeae lineages, as a result of dispersed gene duplication. Phylogeny analyses revealed a shared evolution pattern for MbHF35 in Triticeae, suggesting that these genes have co‐evolved together. We also identified a Pooideae‐specific flavonoid 3′,5′‐hydroxylase (F3′5′H) lineage, termed here Mo_F35H2, which has a higher amino acid similarity with eudicot F3′5′Hs, demonstrating a scenario of convergent evolution. Indeed, selection tests identified 13 amino acid residues in Mo_F35H2 that underwent positive selection, possibly driven by protein thermostablility selection. Furthermore, through the interrogation of barley germplasm there is evidence that HvMYB4H and HvMYC4H have undergone human selection. Collectively, our study favours blue aleurone as a recently evolved trait resulting from environmental adaptation. Our findings provide an evolutionary explanation for the absence of blue anthocyanins in other cereals and highlight the importance of gene functional divergence for plant diversity and environmental adaptation.     

Welfare of Apes in Captive Environments: Comments On,and By,a Specific Group of Apes

Accurately determining the proper captive environment for apes requires adequately assessing the psychological similarities between apes and humans. Scientists currently believe apes lack mental complexity (Millikan, 2006 Millikan, R. G. 2006. “Styles of rationality”. In Rational animals?, Edited by: Hurley, S. and Nudds, M. 117–126. Oxford, , England: Oxford University Press.. [Crossref] , [Google Scholar]), raising questions concerning the evolution of human culture from ape-like societies (Tomasello, 1999 Tomasello, M. 1999. The cultural origins of human cognition, Cambridge, , MA: Harvard University Press..  [Google Scholar]). A long-term cultural study with bonobos suggests less intellectual divergence from humans than currently postulated (Savage-Rumbaugh, 2005 Savage-Rumbaugh, E. S. 2005. “Individual differences in language competencies in apes resulting from unique rearing conditions imposed by different first epistemologies”. In Symbol use and symbolic representation, Edited by: Namy, L. L. 199–219. Mahwah, , NJ: Lawrence Erlbaum Associates, Inc..  [Google Scholar]). Because humans view apes as mentally limited, some current captive environments may appear idyllic while offering only an illusion of appropriate care, derived from a simplistic view of what apes are, rather than what they might be. This perception of apes determines their handling, which determines their mental development, which perpetuates the prevailing perception. Only breaking this cycle will allow the current perception of apes to change. Their usual captive environment limits any demonstration of culture. However, the bonobo study reveals what ape culture can become, which should affect future welfare considerations for at least those species genetically close to humans (bonobos and chimpanzees). Development of a languaged bonobo culture allows these nonhuman animals to provide their own responses regarding adequate ape welfare.