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Context: Silver banksia (Banksia marginata) savannas of south-eastern Australia were formerly widespread but are now largely cleared and fragmented, with small populations often showing recruitment limitation. Which may, in part, be due to seed predation by yellow-tailed black cockatoos (Zanda funerea), which have been observed foraging for seed. Aims: The study aimed to investigate the impact of pre-dispersal seed predation by yellow-tailed black cockatoos on fruit crop between early development and seed release. Additionally, we wanted to assess seed fitness from partially damaged and discarded cones. Methods: The study quantified silver banksia infructescence removal at four populations between early December and seed release in March. We also quantified seed mass and germinability of seeds from cones removed in December, February and March. Key results: All populations experienced significant seed predation (>50%), with almost complete removal of cones from some populations. Early removal limits seed release from cones (only 18% of early removed follicles released seed). Further, early removal also significantly reduced seed mass and germination. Conclusions: Pre-dispersal seed predation by cockatoos is likely to act as a strong filter for recruitment limitation in silver banksia, by negatively affecting annual seed crop size, seed fitness and germinability. Implications: Our study showed the potential impact fragmentation can have on antagonistic plant–animal interactions. Small, isolated B. marginata populations are likely to continue to decline without active strategies to remedy seed predation such as large-scale restoration. Photograph showing development stages of the infructescence and follicles. Fragmentation can interrupt many plant–animal interactions with lasting effects on plant populations. Silver banksia is a highly fragmented but functionally important tree species and important food plant for yellow-tailed black cockatoos. In this study, we document exceptionally high rates of seed predation, development-dependent failure of follicle release from discarded cones, and reduced seed fitness of discarded seeds in fragmented populations of silver banksia. [ABSTRACT FROM AUTHOR]

Proteins are highly complex systems, exhibiting a substantial degree of structural variability in their folded state. In the presence of denaturants, the heterogeneity is greatly enhanced, and fluctuations among vast numbers of folded and unfolded conformations occur via many different pathways. Here, we have studied the structure and dynamics of the small enzyme ribonuclease HI (RNase H) in the presence of the chemical denaturant guanidinium chloride (GdmCI) using single-molecule fluorescence microscopy, with a particular focus on the characterization of the unfolded-state ensemble. A dye pair was specifically attached to the enzyme to measure structural changes through Forster resonance energy transfer (FRET). Enzyme immobilization on star-polymer surfaces that were specially developed for negligible interaction with folded and unfolded proteins enabled us to monitor conformational changes of individual proteins for several hundred seconds. FRET efficiency histograms were calculated from confocal scan images. They showed an expansion of the unfolded proteins with increasing GdmCI concentration. Cross-correlation analysis of donor and acceptor fluorescence intensity time traces from single molecules revealed reconfiguration of the polypeptide chain on a timescale of [approximately equal to] 20 [micro]s at 1.7 M GdmCI. Slow conformational dynamics gave rise to characteristic, stepwise FRET efficiency changes. Transitions between folded and unfolded enzyme molecules occurred on the 100-s timescale, in excellent agreement with bulk denaturation experiments. Transitions between unfolded conformations were more frequent, with characteristic times of [approximately equal to] 2 s. These data were analyzed to obtain information on the free energy landscape of RNase H in the presence of chemical denaturants. fluorescence resonance energy transfer | guanidinium chloride | protein folding | RNase H | single-molecule spectroscopy

The biocompatibility of glass surfaces that are modified by protein layers or linear poly(ethylene glycol) (PEG) brushes are characterized to determine the optimal treatment for the immobilization of single biomolecules by specific attachment. The results indicate the importance of a thorough surface characterization and design in fluorescence studies of immobilized single biomolecules.

Research has been conducted on the bacteriorhodopsin. The temperature dependence of the bacteriorhodopsin's FT-IR spectra as a function of pH has been examined and the results indicate a strong dependence of the irreversible melting transition on the pH of the native bacteriorhodopsin.

The factors that control the structure and high stability of the protein bacteriohodopsin are determined by using calorimetry and spectroscopic experiments. Studies has reviewed that the unfolding of bR contributes much to its thermal stability.

CdSe/ZnS quantum dots (QDs) conjugated to biomolecules that quench their fluorescence, particularly dopamine, have particular spectral properties that allow determination of the number of conjugates per particle, namely, photoenhancement and [...]

The interacting surfaces that are fictionalized by suitable linker groups to immobilize proteins in their narrative confirmation can be prepared by the spin coating. These coatings form a versatile platform for biofunctional and biomimetic surfaces and single molecule fluorescence microscopy studies on immobilized proteins.

The development of the Sonic Pathfinder, a new electronic travel aid, is described. The aim has been to produce an aid that gives the user useful information for safe, stress-free travel rather than to provide an electronic surrogate for vision. (Author/CL)