Predation on eggs of Schneider’s dwarf caiman,Paleosuchus trigonatus (Schneider, 1807), by armadillos and other predators

Nests of Schneider’s dwarf caiman, Paleosuchus trigonatus, were located in the forests around three streams that drain into the Xingu River, Brazilian Amazonia, in October 2014. Camera traps were installed at the edge of four nests to document predators and female parental care. At two nests, females unsuccessfully defended their nests against one or more giant armadillos, Priodontes maximus, and nine-banded armadillos, Dasypus novemcinctus. Both armadillo species responded to the attack by fleeing and returning on the opposite side of the nest by going around the tree under which the nest was located. Giant armadillos have never before been recorded consuming caiman eggs and their diet has been described as consisting mostly of ants and termites. Another species of armadillo, Cabassous unicinctus, was also registered digging into a nest and probably consuming eggs, though it is generally considered to be primarily insectivorous. A tayra (Eira barbara), lizard (Tupinambis teguixin) and coati (Nasua nasua) were also registered taking eggs from nests during the day, but we obtained no registers of nest defence by caimans during the day. The three nests were attacked after 60 days of incubation, when the eggs were well developed.     

Cryptic subarctic diversity: a new bumblebee species from the Yukon and Alaska (Hymenoptera: Apidae)

It is nearly 90 years since a bumblebee species has been described for the first time from Canada or the USA that was previously unrecognised by science. We describe and illustrate Bombus(Alpinobombus) kluanensis sp. nov. and begin to map its distribution. This species was discovered through analysis of Cytochrome c Oxidase subunit I barcodes and had been unsuspected on the basis of morphological and colour characteristics. So far, 247 female specimens considered to belong to this species are known from the subarctic mountains associated with the Denali Fault running from the Alaska Range (Alaska, USA) to Kluane in the Saint Elias Mountains (Yukon, Canada). A checklist of all species of the subgenus Alpinobombus worldwide is provided.

http://zoobank.org/urn:lsid:zoobank.org:pub:78D524DD-FFBA-4BC4-8D39-3EF4F6BDD39E     

New findings of Hexalona-branch representatives in Brazil,with a description of Prenda gen. nov. (Crustacea: Anomopoda: Aloninae)

Altogether, Coronatella and Hexalona-branches are considered the main lineages of Aloninae – a subfamily of common bottom-dwelling microcrustaceans in freshwater environments. Although the taxonomic features of Brazilian members of the Hexalona-branch have been summarised for species from the costata-group and affinis-group, a revision of other widely distributed species in the world is still lacking in this country. The aim of this paper was to study the morphology of Brazilian populations from the guttata-group and intermedia-group, and to describe a new genus from the Hexalona-branch. The parthenogenetic females of Alona cf. guttata from Brazil have similar morphology when compared to data from the literature, but the armature of the terminal claw of its males seems to be different from those of Alona guttata sensu stricto, Alona barbulata and Alona werestschagini. The intermedia-group is formed by Alona elisae sp. nov., which seems to be endemic to the Cerrado of Brazil Central, and Alona isabellae sp. nov., which is widely distributed in Brazil; this species has a labral keel armed with 2–4 setulae, and postabdomen with setulae of lateral fascicles longer than the level of marginal denticles, morphological traits that differentiate it from Alona elisae sp. nov. Another endemic species from the Hexalona-branch is Prenda arvensis gen. nov. and sp. nov., which has two main head pores, a reduced seta on endite 1 of the first limb, sixth limb is a wide lobe. The potential of biodiversity from the Hexalona-branch from Brazil is still underestimated, and a global revision of the guttata-group and intermedia-group is very important for the progress of Aloninae taxonomy and systematics.

http://zoobank.org/urn:lsid:zoobank.org:pub:0A2E4A30-0C9C-43E8-8E72-1DEDA6AFF3C3     

Taming theory with thought experiments: Understanding and scientific progress

I claim that one way thought experiments contribute to scientific progress is by increasing scientific understanding. Understanding does not have a currently accepted characterization in the philosophical literature, but I argue that we already have ways to test for it. For instance, current pedagogical practice often requires that students demonstrate being in either or both of the following two states: 1) Having grasped the meaning of some relevant theory, concept, law or model, 2) Being able to apply that theory, concept, law or model fruitfully to new instances. Three thought experiments are presented which have been important historically in helping us pass these tests, and two others that cause us to fail. Then I use this operationalization of understanding to clarify the relationships between scientific thought experiments, the understanding they produce, and the progress they enable. I conclude that while no specific instance of understanding (thus conceived) is necessary for scientific progress, understanding in general is.     

Tribbles: novel regulators of cell function; evolutionary aspects

Identification of rate-limiting steps or components of intracellular second messenger systems holds promise to effectively interfere with these pathways under pathological conditions. The emerging literature on a recently identified family of signalling regulator proteins, called tribbles gives interesting clues for how these proteins seem to link several ‘independent’ signal processing systems together. Via their unique way of action, tribbles co-ordinate the activation and suppression of the various interacting signalling pathways and therefore appear to be key in determining cell fate while responding to environmental challenges. This review summarises our current understanding of tribbles function and also provides an evolutionary perspective on the various tribbles genes. Received 10 January 2006; received after revision 20 March 2006; accepted 5 April 2006     

Structural characterization of two papaya chitinases, a family GH19 of glycosyl hydrolases

Two chitinases, able to use tetra-N-acetylglucosamine, chitin and chitosan as substrates, were characterized after purification from Carica papaya latex. The complete amino acid sequence of the major form and about 40% of the minor one were determined through proteolytic digestions and mass spectroscopy analysis. Sequencing demonstrated that both papaya chitinases are members of the family 19 of glycosyl hydrolases (GH19). Based on the known 3-D structures of other members of family GH19, it was expected that papaya chitinases would adopt all-alpha structures. However, circular dichroism and infrared spectroscopy indicated, for the papaya chitinases, a content of 15–20% of extended structures besides the expected 40% of alpha helices. Since the fully sequenced papaya chitinase contains a large number of proline residues the possibility that papaya chitinase contains polyproline II stretches was examined in the context of their resistance against proteolytic degradation. Received 11 July 2006; received after revision 13 October 2006; accepted 25 October 2006     

Snake venom components and their applications in biomedicine

Snake envenomation is a socio-medical problem of considerable magnitude. About 2.5 million people are bitten by snakes annually, more than 100,000 fatally. However, although bites can be deadly, snake venom is a natural biological resource that contains several components of potential therapeutic value. Venom has been used in the treatment of a variety of pathophysiological conditions in Ayurveda, homeopathy and folk medicine. With the advent of biotechnology, the efficacy of such treatments has been substantiated by purifying components of venom and delineating their therapeutic properties. This review will focus on certain snake venom components and their applications in health and disease. Received 6 July 2006; received after revision 14 August 2006; accepted 28 September 2006     

DNA methylation of fly genes and transposons

The use of anti-5-methylcytosine antibodies in affinity columns allowed the identification of methylated sequences in the genome of Drosophila melanogaster adults. In view of the presence of transposable elements amongst the identified sequences, it has been suggested that DNA methylation is involved in transposon control in the fly genome. On the contrary, a reanalysis of these data furnishes several intriguing elements that could raise new questions about the role that DNA methylation plays in the fly genome. The aim of the present paper is to discuss some features that emerge from the analysis of the identified methylated sequences. Received 26 January 2006; received after revision 8 May 2006; accepted 2 June 2006     

In vivo matrix-guided human mesenchymal stem cells

Microfracture of subchondral bone results in intrinsic repair of cartilage defects. Stem or progenitor cells from bone marrow have been proposed to be involved in this regenerative process. Here, we demonstrate for the first time that mesenchymal stem (MS) cells can in fact be recovered from matrix material saturated with cells from bone marrow after microfracture. This also introduces a new technique for MS cell isolation during arthroscopic treatment. MS cells were phenotyped using specific cell surface antibodies. Differentiation of the MS cells into the adipogenic, chondrogenic and osteogenic lineage could be demonstrated by cultivation of MS cells as a monolayer, as micromass bodies or mesenchymal microspheres. This study demonstrates that MS cells can be attracted to a cartilage defect by guidance of a collagenous matrix after perforating subchondral bone. Protocols for application of MS cells in restoration of cartilage tissue include an initial invasive biopsy to obtain the MS cells and time-wasting in vitro proliferation and possibly differentiation of the cells before implantation. The new technique already includes attraction of MS cells to sites of cartilage defects and therefore may overcome the necessity of in vitro proliferation and differentiation of MS cells prior to transplantation. Received 3 November 2005; received after revision 15 December 2005; accepted 4 January 2006