Use of autonomous audio recordings for the rapid inventory of birds in the white‐sand forests of the Peruvian Amazon

White‐sand forests are patchily distributed ecosystems covering just 5% of Amazonia that host many specialist species of birds not found elsewhere, and these forests are threatened due to their small size and human exploitation of sand for construction projects. As a result, many species of birds that are white‐sand specialists are at risk of extinction, and immediate conservation action is paramount for their survival. Our objective was to evaluate current survey methods and determine the relative effect of the size of patches of these forests on the presence or absence of white‐sand specialists. Using point counts and autonomous recorders, we surveyed avian assemblages occupying patches of white‐sand forest in the Peruvian Amazon in April 2018. Overall, we detected 126 species, including 21 white‐sand forest specialists. We detected significantly more species of birds per survey point with autonomous recorders than point counts. We also found a negative relationship between avian species richness and distance from the edge of patches of white‐sand forest, but a significant, positive relationship when only counting white‐sand specialists. Although we detected more species with autonomous recorders, point counts were more effective for detecting canopy‐dwelling passerines. Therefore, we recommend that investigators conducting surveys for rare and patchily distributed species in the tropics use a mixed‐method approach that incorporates both autonomous recorders and visual observation. Finally, our results suggest that conserving large, continuous patches of white‐sand forest may increase the likelihood of survival of species of birds that are white‐sand specialists.     

Determination of AMP in the rat heart using skeletal muscle AMP deaminase

A new simple enzymatic method for measuring AMP content in freeze-clamped rat heart is presented. The method is based on the ammonia estimation after the deamination of 5'-AMP by muscle 5'-adenylic acid deaminase. The minimum detectable amount of AMP was about 1.5 nmol. The recovery of AMP added to the tissue homogenate was 94%. The variance coefficient evaluated by assaying five samples from one tissue extract was equal to 5%. AMP content of rat heart (0.28 mumol/g wet tissue) is comparable with the values reported by others.     

"Pertussis toxin induces tachycardia and impairs the increase in blood pressure produced by alpha 2-adrenergic agonists"

Administration of purified pertussis toxin to rats induced persistent tachycardia, (observed in conscious rats but not after pithing); as little as 0.05 microgram/100 g produced a significant effect. Pertussis toxin-treatment did not affected the pressor response produced in the pithed rats by the alpha 2-adrenergic agonist methoxamine but markedly diminished the pressor effect of the alpha 2-adrenergic agonists clonidine and azepexole. A role of adenylate cyclase inhibition in the action of postsynaptic vascular alpha 2-adrenergic receptors is suggested.     

The heparin binding domain of S-protein/vitronectin binds to complement components C7, C8, and C9 and perforin from cytolytic T-cells and inhibits their lytic activities

S-Protein/vitronectin is a serum glycoprotein that inhibits the lytic activity of the membrane attack complex of complement, i.e., of the complex including the proteins C5b, C6, C7, C8, and C9n. We show that intact S-protein/vitronectin or its cyanogen bromide generated fragments also inhibit the hemolysis mediated by perforin from cytotoxic T-cells at 45 and 11 microM, respectively. The glycosaminoglycan binding site of S-protein/vitronectin is responsible for the inhibition, since a synthetic peptide corresponding to a part of this highly basic domain (amino acid residues 348-360) inhibits complement- as well as perforin-mediated cytolysis. In the case of C9, the synthetic peptide binds to the acidic residues occurring in its N-terminal cysteine-rich domain (residues 101-111). Antibodies raised against this particular segment react 25-fold better with the polymerized form of C9 as compared with its monomeric form, indicating that this site becomes exposed only upon the hydrophilic-amphiphilic transition of C9. Since the cysteine-rich domain of C9 has been shown to be highly conserved in C6, C7, and C8 as well as in perforin, the inhibition of the lytic activities of these molecules by S-protein/vitronectin or by peptides corresponding to its heparin binding site may be explained by a similar mechanism.     

Extending the Cellulosome Paradigm: the Modular Clostridium thermocellum Cellulosomal Serpin PinA Is a Broad-Spectrum Inhibitor of Subtilisin-Like Proteases

Clostridium thermocellum encodes a cellulosomal, modular, and thermostable serine protease inhibitor (serpin), PinA. PinA stability but not inhibitory activity is affected by the Fn(III) and Doc(I) domains, and PinA is a broad inhibitor of subtilisin-like proteases and may play a key role in protecting the cellulosome from protease attack.     

Mysterious bio-duck sound attributed to the Antarctic minke whale (Balaenoptera bonaerensis)

For decades, the bio-duck sound has been recorded in the Southern Ocean, but the animal producing it has remained a mystery. Heard mainly during austral winter in the Southern Ocean, this ubiquitous sound has been recorded in Antarctic waters and contemporaneously off the Australian west coast. Here, we present conclusive evidence that the bio-duck sound is produced by Antarctic minke whales (Balaenoptera bonaerensis). We analysed data from multi-sensor acoustic recording tags that included intense bio-duck sounds as well as singular downsweeps that have previously been attributed to this species. This finding allows the interpretation of a wealth of long-term acoustic recordings for this previously acoustically concealed species, which will improve our understanding of the distribution, abundance and behaviour of Antarctic minke whales. This is critical information for a species that inhabits a difficult to access sea-ice environment that is changing rapidly in some regions and has been the subject of contentious lethal sampling efforts and ongoing international legal action.