What's inside a sauropod limb? First three-dimensional investigation of the limb long bone microanatomy of a sauropod dinosaur,Nigersaurus taqueti (Neosauropoda,Rebbachisauridae), and implications for the weight-bearing function

Various terrestrial tetrapods convergently evolved to gigantism (large body sizes and masses), the most extreme case being sauropod dinosaurs. Heavy weight-bearing taxa often show external morphological features related to this condition, but also adequacy in their limb bone inner structure: a spongiosa filling the medullary area and a rather thick cortex varying greatly in thickness along the shaft. However, the microanatomical variation in such taxa remains poorly known, especially between different limb elements. We highlight for the first time the three-dimensional microstructure of the six limb long bone types of a sauropod dinosaur, Nigersaurus taqueti. Sampling several specimens of different sizes, we explored within-bone, between-bones, and size-related variations. If a spongiosa fills the medullary area of all bones, the cortex is rather thin and varies only slightly in thickness along the shaft. Zeugopod bones appear more compact than stylopod ones, whereas no particular differences between serially homologous bones are found. Nigersaurus' pattern appears much less extreme than that in heavy terrestrial taxa such as rhinoceroses, but is partly similar to observations in elephants and in two-dimensional sauropod data. Thus, microanatomy may have not been the predominant feature for weight-bearing in sauropods. External features, such as columnarity (shared with elephants) and postcranial pneumaticity, may have played a major role for this function, thus relaxing pressures on microanatomy. Also, sauropods may have been lighter than expected for a given size. Our study calls for further three-dimensional investigations, eventually yielding a framework characterizing more precisely how sauropod gigantism may have been possible.     

Grooming-at-a-distance by exchanging calls in non-human primates

The ‘social bonding hypothesis'' predicts that, in large social groups, functions of gestural grooming should be partially transferred to vocal interactions. Hence, vocal exchanges would have evolved in primates to play the role of grooming-at-a-distance in order to facilitate the maintenance of social cohesion. However, there are few empirical studies testing this hypothesis. To address this point, we compared the rate of contact call exchanges between females in two captive groups of Japanese macaques as a function of female age, dominance rank, genetic relatedness and social affinity measured by spatial proximity and grooming interactions. We found a significant positive relationship between the time spent on grooming by two females and the frequency with which they exchanged calls. Our results conform to the predictions of the social bonding hypothesis, i.e. vocal exchanges can be interpreted as grooming-at-a-distance.     

Microsatellite markers for <Emphasis Type="Italic">Caesalpinia echinata</Emphasis> Lam. (Brazilwood), a tree that named a country

Caesalpinia echinata, commonly known as Pau-brasil (Brazilwood), the famous tree that named Brazil is native to the Atlantic forest. Men extensively exploited it ever since discovery and colonial times due to its value as a source of red dye. As a consequence, Brazilwood is a threatened species with populations reduced to small forest fragments. Ten polymorphic microsatellite loci were developed from an enriched genomic library. Using fluorescently-labeled primers, a total of 83 alleles were found after analyzing a sample of 44 trees. These high genetic information content markers should allow detailed investigations of mating systems, gene flow, population structure and paternity in natural populations.     

Quantifying structural changes and stoichiometry of protein interactions using size and density profiling

Summary The use of Dual Polarisation Interferometry, and emerging analytical biophysical technique, is described for the determination of the optogeometrical properties (thickness and density) at high resolution of adsorbed protein layers at the solid-liquid interface. The technique has been used to quantify, in real time and at subatomic resolution, the structural changes occurring in two well-characterised protein interaction systems, an antibody-antigen interaction and the biotin-streptavidin interaction. The realtime data obtained on structural changes during the interactions is in excellent agreement with previously reported X-ray crystallography and neutron reflection data. The precision of the measurements taken was of the order of 0.01 nm with respect to protein size. The dual-parameter approach also allowed the stoichiometry of both of these interactions to be calculated, giving values that confirm the current understanding of the interactions. This approach provides detailed insights into the inherent and subtle link between structural change and function in proteins, to a degree not previously possible through mass change measurements alone. The technique is expected to find utility in the increasingly important study of protein structure and function.     

Mild reductions in cytosolic NADP-dependent isocitrate dehydrogenase activity result in lower amino acid contents and pigmentation without impacting growth

Transgenic tomato (Solanum lycopersicum) plants were generated targeting the cytosolic NADP-dependent isocitrate dehydrogenase gene (SlICDH1) via the RNA interference approach. The resultant transformants displayed a relatively mild reduction in the expression and activity of the target enzyme in the leaves. However, biochemical analyses revealed that the transgenic lines displayed a considerable shift in metabolism, being characterized by decreases in the levels of the TCA cycle intermediates, total amino acids, photosynthetic pigments, starch and NAD(P)H. The plants showed little change in photosynthesis with the exception of a minor decrease in maximum photosynthetic efficiency (F _v/F _m), and a small decrease in growth compared to the wild type. These results reveal that even small changes in cytosolic NADP-dependent isocitrate dehydrogenase activity lead to noticeable alterations in the activities of enzymes involved in primary nitrate assimilation and in the synthesis of 2-oxoglutarate derived amino acids. These data are discussed within the context of current models for the role of the various isoforms of isocitrate dehydrogenase within plant amino acid metabolism.     

Clonal diversity amongst island populations of alien,invasive Lemna minuta kunth

Biological Invasions - Invasive alien species can negatively impact on newly colonised ecosystems. Thus, it is important to understand factors that facilitate invasiveness. Genetic diversity will...