The indris of Anjanaharibe-Sud,northeastern Madagascar

During a short field trip to the Special Reserve of Anjanaharibe-Sud in northeastern Madagascar, data concerning pelage coloration, behavior (especially vocalization), and ecology of indris were collected. Anjanaharibe-Sud is the northernmost locality of indri distribution. In comparison to the better-known indris from the southern part of their distribution, the indris in this region show different pelage coloration. Several types of loud vocalizations are analyzed, based on a small sample of tape recordings. Their song structure is more complicated than previously reported, containing distinct sequences of duetting. Data on behavior and ecology were collected by interviewing guides and local inhabitants. Some information contrasts with reports on the more southern indri populations. The conservation status of indris in Anjanaharibe-Sud and the future of the reserve are outlined.     

Successful synthesis of a glial-specific blood–brain barrier shuttle peptide following a fragment condensation approach on a solid-phase resin

Successful manual synthesis of the TD2.2 peptide acting as a blood–brain barrier shuttle was achieved. TD2.2 was successfully synthesised by sequential condensation of four protected peptide fragments on solid-phase settings, after several unsuccessful attempts using the stepwise approach. These fragments were chosen to minimise the number of demanding amino acids (in terms of coupling, Fmoc removal) in each fragment that are expected to hamper the overall synthetic process. Thus, the hydrophobic amino acids as well as Arg(Pbf) were strategically spread over multiple fragments rather than having them congested in one fragment. This study shows how a peptide that shows big challenges in the synthesis using the common stepwise elongation methodology can be synthesised with an acceptable purity. It also emphasises that choosing the right fragment with certain amino acid constituents is key for a successful synthesis. It is worth highlighting that lower amounts of reagents were required to synthesise the final peptide with an identical purity to that obtained by the automatic synthesiser.     

Defining null expectations for animal site fidelity

Site fidelity—the tendency to return to previously visited locations—is widespread across taxa. Returns may be driven by several mechanisms, including memory, habitat selection, or chance; however, pattern-based definitions group different generating mechanisms under the same label of ‘site fidelity’, often assuming memory as the main driver. We propose an operational definition of site fidelity as patterns of return that deviate from a null expectation derived from a memory-free movement model. First, using agent-based simulations, we show that without memory, intrinsic movement characteristics and extrinsic landscape characteristics are key determinants of return patterns and that even random movements may generate substantial probabilities of return. Second, we illustrate how to implement our framework empirically to establish ecologically meaningful, system-specific null expectations for site fidelity. Our approach provides a conceptual and operational framework to test hypotheses on site fidelity across systems and scales.     

Stroke research in GenomEUtwin.

Stroke is one of the leading causes of severe disability and death in the world. In the present article we outline possibilities and limitations for future stroke research within the GenomEUtwin. The combined sample of twins born before 1958 from Denmark, Finland, and Sweden, and available for follow-up into the second millennium for non-fatal and fatal stroke events through national inpatient and death registers exceeds 70,000 twin pairs. This sample size will enable the study of genetic influences on stroke and major stroke subtypes. Large samples of twins in GenomEUtwin have been followed up repeatedly through interviews and questionnaires concerning a variety of exposures and potential risk factors for stroke. We briefly outline how this information can be combined with the health register information for epidemiologic and genetic epidemiologic studies of stroke. We also present the number of twin pairs concordant and discordant for stroke in Denmark, Finland and Sweden, and time lags between events for twins concordant for stroke. This information illustrates that the number of affected sib pairs for linkage studies is relatively limited, but the sample sizes are promising for association studies.     

Insertion mutations at the maizeOpaque2 locus induced by transposable element familiesAc, En/Spm andBg

Eight independently isolated unstable alleles of theOpaque2 (O2) locus were analysed genetically and at the DNA level. The whole series of mutations was isolated from a maize strain carrying a wild-typeO2 allele and the transposable elementActivator (Ac) at thewx-m7 allele. Previous work with another unstable allele of the same series has shown that it was indeed caused by the insertion of anAc element. Unexpectedly, the remaining eight mutations were not caused by the designatedAc element, but by other insertions that are structurally similar or identical to one of two different autonomous transposable elements. Six mutations were caused by the insertion of a transposable element of theEnhancer/Suppressor-Mutator (En/Spm) family. Two mutations were the result of the insertion of a transposable element of theBergamo (Bg) family. Genetic tests carried out with plants carrying the unstable mutations demonstrated that all were caused by the insertion of an autonomous transposable element.     

Molecular dynamics of alamethicin transmembrane channels from open-channel current noise analysis.

Conductance noise measurement of the open states of alamethicin transmembrane channels reveals excess noise attributable to cooperative low-frequency molecular dynamics that can generate fluctuations approximately 1 A rms in the effective channel pore radius. Single-channel currents through both persistent and nonpersistent channels with multiple conductance states formed by purified polypeptide alamethicin in artificial phospholipid bilayers isolated onto micropipettes with gigaohm seals were recorded using a voltage-clamp technique with low background noise (rms noise < 3 pA up to 20 kHz). Current noise power spectra between 100 Hz and 20 kHz of each open channel state showed little frequency dependence. Noise from undetected conductance state transitions was insignificant. Johnson and shot noises were evaluated. Current noise caused by electrolyte concentration fluctuation via diffusion was isolated by its dependence on buffer concentration. After removing these contributions, significant current noise remains in all persistent channel states and increases in higher conductance states. In nonpersistent channels, remaining noise occurs primarily in the lowest two states. These fluctuations of channel conductance are attributed to thermal oscillations of the channel molecular conformation and are modeled as a Langevin translational oscillation of alamethicin molecules moving radially from the channel pore, damped mostly by lipid bilayer viscosity.     

Structure and function of adenovirus type 12 defective virions.

Purified human adenovirus type 12 preparations contain defective virions with a lighter density. These defective virions were isolated, and their biological functions and DNA were characterized. They can induce early and late antigens in infected cells and tumors in newborn hamsters with similar efficiency as complete virions. The majority of the DNA molecules from light virions contain deletions mapping near 16% from the left-hand end of the genome. Mechanisms for the generation of these molecules are discussed.