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801.
Z. Campos F. Muniz A. L. J Desbiez W. E. Magnusson 《Journal of Natural History》2016,50(25-26):1543-1548
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. 相似文献
802.
Francisco Diogo R. Sousa Lourdes M.A. Elmoor-Loureiro Sandro Santos 《Journal of Natural History》2016,50(43-44):2727-2768
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 相似文献
803.
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 相似文献
804.
Huet J Wyckmans J Wintjens R Boussard P Raussens V Vandenbussche G Ruysschaert JM Azarkan M Looze Y 《Cellular and molecular life sciences : CMLS》2006,63(24):3042-3054
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 相似文献
805.
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 相似文献
806.
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 相似文献
807.
808.
Memories become stabilized through a time-dependent process that requires gene expression and is commonly known as consolidation. During this time, memories are labile and can be disrupted by a number of interfering events, including electroconvulsive shock, trauma and other learning or the transient effect of drugs such as protein synthesis inhibitors. Once consolidated, memories are insensitive to these disruptions. However, they can again become fragile if recalled or reactivated. Reactivation creates another time-dependent process, known as reconsolidation, during which the memory is restabilized. Here we discuss some of the questions currently debated in the field of memory consolidation and reconsolidation, the molecular and anatomical requirements for both processes and, finally, their functional relationship. 相似文献
809.
Betaine homocysteine S-methyltransferase: just a regulator of homocysteine metabolism? 总被引:1,自引:0,他引:1
Betaine homocysteine methyltransferase (BHMT), a Zn2+-dependent thiolmethyltransferase, contributes to the regulation of homocysteine levels, increases in which are considered
a risk factor for cardiovascular diseases. Most plasma homocysteine is generated through the liver methionine cycle, in which
BHMT metabolizes approximately 25% of this non-protein amino acid. This process allows recovery of one of the three methylation
equivalents used in phosphatidylcholine synthesis through transmethylation, a major homocysteine-producing pathway. Although
BHMT has been known for over 40 years, the difficulties encountered in its isolation precluded detailed studies until very
recently. Thus, the last 10 years, since the sequence became available, have yielded extensive structural and functional data.
Moreover, recent findings offer clues for potential new functions for BHMT. The purpose of this review is to provide an integrated
view of the knowledge available on BHMT, and to analyze its putative roles in other processes through interactions uncover
to date.
Received 26 May 2006; received after revision 3 July 2006; accepted 24 August 2006 相似文献
810.
Liver X receptors in cardiovascular and metabolic disease 总被引:5,自引:0,他引:5
Liver X receptors (LXRs) α and β are nuclear oxysterol receptors and metabolic sensors initially found to regulate cholesterol
metabolism and lipid biosynthesis. Recent studies have elucidated the importance of LXR in the development of cardiovascular
diseases and metabolic disorders. LXR agonists prevent development of atherosclerosis by modulation of metabolic as well as
inflammatory gene expression in rodent models. Moreover, LXR activation inhibits hepatic gluconeogenesis and lowers serum
glucose levels, indicating possible application of LXR activation in the treatment of diabetes mellitus. However, first-generation
LXR agonists elevate hepatic and serum trigylceride levels, making subtype-specific agonists and selective LXR modulators
rather than unselective LXR agonists a potential pharmacological strategy. This review summarizes the multiple physiological
and pathophysiological implications of LXRs and observations that identify LXRs as potential targets for therapeutic interventions
in human cardiovascular and metabolic disease.
Received 30 August 2005; received after revision 10 October 2005; accepted 4 November 2005 相似文献