Massive Seed Predation of Pseudobombax grandiflorum (Bombacaceae) by Parakeets Brotogeris versicolurus (Psittacidae) in a Forest Fragment in Brazil1

Here we report massive seed predation of Pseudobombax grandiflorum (Bombacaceae) by Botogeris versicolurus (Psittacidae) in a forest fragment in Brazil. The intensity of seed predation was very high when compared to other studies in continuous forest, perhaps resulting from a scarcity of resources in such areas. This scarcity may limit the range of parrot's diet to a few plant species. It suggests that studies of Psittacidae seed predation may be important for conservation of some plants in fragments.     

High-performance liquid chromatographic separation of aprotinin-like inhibitors and their determination in very small amounts

A reversed-phase high-performance liquid chromatographic method for the determination and quantitative recovery of fully active aprotinin (the basic pancreatic trypsin inhibitor or Kunitz inhibitor) and aprotinin-like inhibitors in amounts down to 0.5 μg is reported. The method, which allows separation of aprotinin isoinhibitors characterized by small differences in the primary structure with respect to aprotinin itself, appears to be suitable for the quantitation and identification of aprotinin-like inhibitors in human biological fluids, in which they appear to be present at very low levels.     

Behaviour of the Common Moorhen in Rio Grande do Sul, Brazil

This study presents data on behavioural acts performed by the Common Moorhen Gallinula chloropus in southern Brazil, and compares these with the behaviours previously reported for other populations. Focal observations of individuals were conducted in the municipality of Santa Maria, in the central region of the state of Rio Grande do Sul, Brazil. The sampling was done in 2-hour sessions, between January and March of 2007. A total of 20 behavioural acts, grouped in seven categories, were identified and described: locomotion (N = 5 acts), grooming (N = 4), intra-specific behaviour (N = 2), inter-specific behaviour (N = 3), foraging (N = 2), reproduction (N = 2) and rest (N = 2). Among the observed behaviours were acts that are not described in the literature such as greeting of offspring and some feeding acts. Regarding the use of habitat, we observed that this species has a preference for water or aquatic macrophytes, which is contrary to other reports. In the analysis of behavioural daily variation, overall behavioural categories did not vary significantly throughout the day, whereas we observed a significant difference in the use of categories during the periods 11:00 am–1:00 pm, 1:00–3:00 pm and 5:00–7:00 pm. The contrasting data between studies indicate that the variation between habitats and ecological interactions may generate different selective pressures on the behaviour of G. chloropus.     

Persistence of the effect of frugivore identity on post‐dispersal seed fate: consequences for the assessment of functional redundancy

Large frugivores play an important role as seed dispersers and their extinction may affect plant regeneration. The consequences of such extinctions depend on the likelihood of other species being functionally redundant and on how post‐dispersal events are affected. We assess the functional redundancy of two seed dispersers of the Atlantic Forest, the muriqui (Brachyteles arachnoides) and the tapir (Tapirus terrestris) through the comparison of their seed dispersal quality, taking into account post‐dispersal events. We compare tapirs and muriquis for: (1) the dung beetle community associated with their feces; (2) the seed burial probability and burial depth by dung beetles; and (3) the seed mortality due to predators or other causes according to burial depth. We determine how seed burial affects seed dispersal effectiveness (SDE) and compare the dispersal quality of four plant species dispersed by these frugivores. Muriqui feces attract 16‐fold more dung beetles per gram of fecal matter and seeds experience 10.5‐fold more burial than seeds in tapir feces. In both feces types, seed mortality due to predation decreases with burial depth but seed mortality due to other causes increases. Total seed mortality differ within plant species according to the primary disperser. Therefore, the effect of seed burial on SDE varies according to the plant species, burial depth, and primary disperser. As tapirs and muriquis differently affect the seed fate, they are not functionally redundant. Since the effect of the primary disperser persists into the post‐dispersal events, we should consider the cascading effects of these processes when assessing functional redundancy.     

Overcoming phylogenetic and geographic uncertainties to test for correlates of range size evolution in gymnophthalmid lizards

Patterns of range size evolution are important for developing an evolutionary biogeographical theory and supporting conservation actions. Determining those patterns is however hampered by multiple factors acting on range size and by our uncertainty with regard to species' phylogenetic relationships and geographic distribution. In addition, given the diversity of analytic approaches existing in the literature, there are concerns regarding whether different methods might lead to different patterns. Here, we addressed these uncertainties in order to test for correlations between the evolution of morphology (body size and shape) and range size. We studied lizards of the family Gymnophthalmidae, representing changes of an order of magnitude in body size and also two independent lineages with limb‐reduced (snake‐like) morphs. We used phylogenetic multivariate methods (pPCA) to control for allometric effects of body size over shape. Then, we performed multiple regressions under three approaches: ‘naive’ least squares, Bayesian comparative methods that accounted for uncertainties in trait optimization, tree topology and branch length, and a novel permutative procedure based on phylogenetic generalized least squares (pGLS) to assess the robustness of our relationships to uncertainties in the range sizes of the species studied. All approaches led to the same answer: only body size was related to range size. While bigger gymnophthalmids tend to have relatively large ranges, small species can have either small or large ones. Our results’ robustness to strong uncertainties in both phylogenetic relationships and range sizes shows there are opportunities for overcoming those problems and produce reliable patterns of range size evolution. However, interpretation of the processes driving patterns of range size evolution will still require advances in phylogenetic and taxonomic knowledge. We discuss the application of morphology–range size relationships to conservation planning in the light of existing uncertainties in the geographic knowledge of our studied species group and workarounds for data availability.     

Mosquito traps designed to capture Aedes aegypti (Diptera: Culicidae) females: preliminary comparison of Adultrap, MosquiTRAP and backpack aspirator efficiency in a dengue-endemic area of Brazil

In this report, the efficiency of Adultrap under field conditions is compared to a CDC backpack aspirator and to MosquiTRAP. An urban dengue-endemic area of Rio de Janeiro was selected to evaluate the efficiency of mosquito traps in capturing Aedes aegypti females. Adultrap and aspirator captured similar numbers of Ae. aegypti females, with the former showing high specificity to gravid individuals (93.6%). A subsequent mark-release-recapture experiment was conducted to evaluate Adultrap and MosquiTRAP efficiency concomitantly. With a 6.34% recapture rate, MosquiTRAP captured a higher mean number of female Ae. aegypti per trap than Adultrap (chi2 = 14.26; df = 1; p < 0,05). However, some MosquiTRAPs (28.12%) contained immature Ae. aegypti after 18 days of exposure in the field and could be pointed as an oviposition site for female mosquitoes. Both trapping methods, designed to collect gravid Ae. aegypti females, seem to be efficient, reliable and may aid routine Ae. aegypti surveillance.     

Homologous recombination in real time: DNA strand exchange by RecA

Homologous recombination, the exchange of strands between different DNA molecules, is essential for proper maintenance and accurate duplication of the genome. Using magnetic tweezers, we monitor RecA-driven homologous recombination of individual DNA molecules in real time. We resolve several key aspects of DNA structure during and after strand exchange. Changes in DNA length and twist yield helical parameters for the protein-bound three-stranded structure in conditions in which ATP was not hydrolyzed. When strand exchange was completed under ATP hydrolysis conditions that allow protein dissociation, a "D wrap" structure formed. During homologous recombination, strand invasion at one end and RecA dissociation at the other end occurred at the same rate, and our single-molecule analysis indicated that a region of only about 80 bp is actively involved in the synapsis at any time during the entire reaction involving a long ( approximately 1 kb) region of homology.     

Mechanism of inhibition of wt-dihydrofolate reductase from E. coli by tea epigallocatechin-gallate

Dihydrofolate reductase (DHFR) is a ubiquitous enzyme involved in major biological process, including DNA synthesis and cancer inhibition, and its modulation is the object of extensive structural, kinetic, and pharmacological studies. In particular, earlier studies showed that green tea catechins are powerful inhibitors of bovine liver and chicken liver DHFR. In this article, we report the results of inhibition kinetics for the enzyme from another source (DHFR from E. coli) exerted by (-)-epigallocatechingallate (EGCG). Using different analytical techniques, we reported that EGCG acts as a bisubstrate inhibitor on the bacterial DHFR. Moreover, the combined approach of biosensor, kinetic, and molecular modelling analysis disclosed the ability of EGCG to bind to the enzyme both on substrate (DHF) and cofactor (NADPH) site. Collectively, our data have confirmed the selectivity of antifolate compounds with respect to the different source of enzyme (bacterial or mammalian DHFR) and the possible role of tea catechins as chemopreventive agents.     

Effective Binding Force Calculation in Dimeric Proteins

We apply the Blue Moon constrained Molecular Dynamics technique to study a particular case of molecular recognition, one of the main issues of modern molecular biology. We investigate the effects of mutation of interface residues on the binding strength of the dimeric protein superoxide dismutase from Photobacterium leiognathi. With our technique we produce a specific path describing the separation of the dimers and we calculate the effective mean force involved in the process. We apply the method to two mutants and compare the results with those obtained in an earlier calculation on the native enzyme. The method is sensitive to the mutations and allows us to establish a semi-quantitative hierarchy for the association strengths of the three enzymes.