Early Seedling Growth in Normal and Opaque-2 Zea mays L. cv. Maya: I. COMPOSITION AND MOBILIZATION OF THE ENDOSPERM PROTEIN RESERVE

Grain of op-2 Maya have a higher total protein content in bothendosperm and germ than normal maize. In large grain, differencesin total grain protein are due mainly to the endosperm whilein small grain, differences are due to the germ, particularlythe scutellum which is larger in op-2 kernels. Reserve proteincomposition was distinct: op-2 endosperms showed an increasein the proportions of albumins, globulins, and the glutelinG₃ fraction which was accompanied by a marked decrease in zeincontent in comparison with normal endosperms. During endosperm depletion there was a net increase in the salt-solublefraction prior to day 3 from imbibition; glutelins and zeinhowever decreased throughout, the former being degraded at initiallyfaster rates. In general, regardless of protein composition,the most abundant fraction was utilized most rapidly. Water uptake during imbibition was greater in op-2 grain, thoughno differences in axis growth in terms of dry weight or laminaarea were apparent at the end of reserve degradation. In bothnormal and op-2 seedlings, protein was mobilized both earlierand faster than endosperm dry matter and the shoot, principallythe first leaf lamina, received more reserve nitrogen than theroot.     

Assessing the nesting strategies of Late Cretaceous titanosaurs: 3‐D clutch geometry from a new megaloolithid eggsite

Vila, B., Galobart, À., Oms, O., Poza, B. & Bravo, A.M. 2009: Assessing the nesting strategies of Late Cretaceous titanosaurs: 3‐D clutch geometry from a new megaloolithid eggsite. Lethaia, Vol. 43, pp. 197–208. Detailed mapping and excavation at the egg locality of Font del Bullidor (Vallcebre Syncline, NE Iberian Peninsula) document various clutches with megaloolithid (Megaloolithus siruguei) eggs and provide significant information on the mode of incubation of Late Cretaceous titanosaurs. Clutches of eggs are preserved in a greyish lagoonal mudstone deposited overlying a sinuous channel infill. Despite the lithological uniformity of the mudstone, clutch architecture can be inferred from the topographical position of the eggs within some clutches. Mapping methods underscore the importance of documenting the spatial relationship of the egg‐bearing bed and the mapping plan, as well as an accurate 3‐D coordinate acquisition. Both geometry of the clutches and taphonomic observations on particular eggs indicate that eggs were laid in a shallow pit excavated into the substrate. Most of the eggs were incubated under a cover of sediment before hatching or cracking. This corroborates previous inferences on nesting mode. □Clutch, dinosaurs, eggs, Maastrichtian, Megaloolithus siruguei, Pyrenees.     

Cryptic diversity within the Moroccan endemic day geckos Quedenfeldtia (Squamata: Gekkonidae): a multidisciplinary approach using genetic,morphological and ecological data

Quedenfeldtia (Boettger, 1883) is a genus of diurnal geckos, endemic to the Atlas Mountains in Morocco, with two species being recognized: Quedenfeldtia moerens and Quedenfeldtia trachyblepharus. Quedenfeldtia moerens is found across a wide variety of habitats, from sea level to 3000 m a.s.l., whereas Q. trachyblepharus occupies exclusively high mountain regions reaching up to 4000 m a.s.l. This differentiation, offers an interesting model for study biogeographical patterns and evolutionary scenarios in a North African endemic. Analysis of two mitochondrial (12S rRNA and ND4) and four nuclear (ACM4, MC1R, PDC, and Rag1) DNA markers revealed high genetic variation, consistent with other recent phylogeographical studies, and with the two currently described species. However, within each species, a subdivision into two groups with geographical consistence was found. Multivariate morphological analyses confirmed the existence of two main phenotypes, whereas ecological niche modelling identified various environmental variables associated with the distribution of each species, and helped to predict occurrences outside the confirmed ranges. The results obtained in the present study indicate the possible existence of additional ‘cryptic’ species within this genus, a condition found in many North African reptiles, and particularly common in geckos. In general, North African montane fauna appears to reflect the occurrence of diverse palaeoendemics, as seen in Central Africa Mountain systems, rather than the pattern of recent postglacial recolonization observed in Europe. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Diversity patterns of stygobiotic crustaceans across multiple spatial scales in Europe

1. Using species distribution data from 111 aquifers distributed in nine European regions, we examined the pairwise relationships between local species richness (LSR), dissimilarity in species composition among localities, and regional species richness (RSR). In addition, we quantified the relative contribution of three nested spatial units – aquifers, catchments and regions – to the overall richness of groundwater crustaceans.
2. The average number of species in karst and porous aquifers (LSR) varied significantly among regions and was dependent upon the richness of the regional species pool (RSR). LSR–RSR relationships differed between habitats: species richness in karstic local communities increased linearly with richness of the surrounding region, whereas that of porous local communities levelled off beyond a certain value of RSR.
3. Dissimilarity in species composition among aquifers of a region increased significantly with increasing regional richness because of stronger habitat specialisation and a decrease in the geographic range of species among karst aquifers. Species turnover among karst aquifers was positively related to RSR, whereas this relationship was not significant for porous aquifers.
4. The contribution of a given spatial unit to total richness increased as size of the spatial unit increased, although 72% of the overall richness was attributed to among-region diversity. Differences in community composition between similar habitats in different regions were typically more pronounced than between nearby communities from different habitats.
5. We conclude by calling for biodiversity assessment methods and conservation strategies that explicitly integrate the importance of turnover in community composition and habitat dissimilarity at multiple spatial scales.     

cpFBPaseII, a novel redox-independent chloroplastic isoform of fructose-1,6-bisphosphatase

A full-length FBPase cDNA has been isolated from Fragaria  ×  ananassa (strawberry) corresponding to a novel putative chloroplastic FBPase but lacking the regulatory redox domain, a characteristic of the plastidial isoenzyme (cpFBPaseI). Another outstanding feature of this novel isoform, called cpFBPaseII, is the absence of the canonical active site. Enzymatic assays with cpFBPaseII evidenced clear Mg²⁺-dependent FBPase activity and a K _m for fructose-1,6-bisphosphate (FBP) of 1.3 m m . Immunolocalization experiments and chloroplast isolation confirmed that the new isoenzyme is located in the stroma. Nevertheless, unlike cpFBPaseI, which is redox activated, cpFBPaseII did not increase its activity in the presence of either DTT or thioredoxin f (TRX f ) and is resistant to H₂O₂ inactivation. Additionally, the novel isoform was able to complement the growth deficiency of the yeast FBP1 deletion fed with a non-fermentable carbon source. Furthermore, orthologues are restricted to land plants, suggesting that cpFBPaseII is a novel and an intriguing chloroplastic FBPase that emerged late in the evolution of photosynthetic organisms, possibly because of a pressing need of land plants.     

Greenhouse gas,upwelling‐favorable winds,and the future of coastal ocean upwelling ecosystems

Coastal ocean upwelling ecosystems generally represent the most productive large marine ecosystems of the world's oceans, in terms of both primary production rates and tonnages of exploitable fish produced. The Peruvian upwelling system, in particular, stands out as a major factor in world fish production. The Pacific trade winds have traditionally been considered to be the primary driving force for the upwelling system off Peru, but are projected to weaken as climate change proceeds. This leads to concern that the upwelling process in the Peru system, to which its productivity is linked, may likewise weaken. However, other mechanisms involving greenhouse‐associated intensification of thermal low‐pressure cells over the coastal landmasses of upwelling regions suggest general intensification of wind‐driven ocean upwelling in coastal upwelling regions of the world's oceans. But although certain empirical results have supported this expectation, it has not been consistently corroborated in climate model simulations, possibly because the scale of the coastal intensification may be small relative to the scales that are appropriately reflected in the standard models. Here we summarize available evidence for the intensification mechanism and present a proxy test that uses variations in water vapor, the dominant natural greenhouse gas, to offer multiple‐realization empirical evidence for action of the proposed mechanism in the real world situation. While many potential consequences to the future of marine ecosystems would codepend on climate change‐related changes in the thermocline and nutricline structures, an important subset, involving potential increased propensities for hypoxia, noxious gas eruptions, toxic red tide blooms, and/or jellyfish outbreaks, may depend more directly on changes in the upwelling‐favorable wind itself. A prospective role of fisheries in either mitigating or reinforcing this particular class of effects is suggested.