Phylogenetic evidence for a flower size and number trade-off

The size and number of flowers displayed together on an inflorescence (floral display) influences pollinator attraction and pollen transfer and receipt, and is integral to plant reproductive success and fitness. Life history theory predicts that the evolution of floral display is constrained by trade-offs between the size and number of flowers and inflorescences. Indeed, a trade-off between flower size and flower number is a key assumption of models of inflorescence architecture and the evolution of floral display. Surprisingly, however, empirical evidence for the trade-off is limited. In particular, there is a lack of phylogenetic evidence for a trade-off between flower size and number. Analyses of phylogenetic independent contrasts (PICs) of 251 angiosperm species spanning 63 families yielded a significant negative correlation between flower size and flower number. At smaller phylogenetic scales, analyses of individual genera did not always find evidence of a trade-off, a result consistent with previous studies that have examined the trade-off for a single species or genus. Ours is the first study to support an angiosperm-wide trade-off between flower size and number and supports the theory that life history constraints have influenced the evolution of floral display.     

Factors Affecting the Chemical Durability of Glass Used in the Pharmaceutical Industry

Delamination, or the generation of glass flakes in vials used to contain parenteral drug products, continues to be a persistent problem in the pharmaceutical industry. To understand all of the factors that might contribute to delamination, a statistical design of experiments was implemented to describe this loss of chemical integrity for glass vials. Phase I of this study focused on the effects of thermal exposure (prior to product filling) on the surface chemistry of glass vials. Even though such temperatures are below the glass transition temperature for the glass, and parenteral compounds are injected directly into the body, data must be collected to show that the glass was not phase separating. Phase II of these studies examined the combined effects of thermal exposure, glass chemistry, and exposure to pharmaceutically relevant molecules on glass delamination. A variety of tools was used to examine the glass and the solution contained in the vial including: scanning electron microscopy and dynamic secondary ion mass spectroscopy for the glass; and visual examination, pH measurements, laser particle counting, and inductively coupled plasma–optical emission spectrometry for the analysis of the solution. The combined results of phase I and II showed depyrogenation does not play a significant role in delamination. Terminal sterilization, glass chemistry, and solution chemistry are the key factors in the generation of glass flakes. Dissolution of silica may be an effective indicator that delamination will occur with a given liquid stored in glass. Finally, delamination should not be defined by the appearance of visible glass particulates. There is a mechanical component in the delamination process whereby the flakes must break away from the interior vial surface. Delamination should be defined by the observation of flakes on the interior surface of the vial, which can be detected by several other analytical techniques.     

Effect of birth season on circadian typology appearing in Japanese young children aged 2 to 12 years disappears in older students aged 18 to 25 years

Several studies suggest that season of birth differentially affects the physiological characteristics of humans. Those living at relatively high latitude, such as Canada, Spain, and Italy (44°N-45°N), and born in the fall tended to be "morning-type" persons in comparison to those born in other seasons. There are relatively little data on the affect of season of birth on people residing at low latitude. Here the authors show that at low latitude, Kochi, Japan (33°N), the effect of season of birth on the morningness chronotype is confined to young children aged 1-12 yrs, disappearing in elderly persons. Only female participants aged 2-12 yrs born in the fall, especially in November, were significantly morning-typed (p < .001) in comparison to those born in the other seasons, whereas there were no such significant season-of-birth differences in morningness-eveningness preference among male participants. Moreover, both female and male participants aged 13-25 yrs showed no significant seasonal differences in morningness-eveningness preference. The small effects detected in this study might be due to smaller seasonal change in day length at the relatively lower latitude of Kochi.     

A new mitochondrial pH biosensor for quantitative assessment of pancreatic β-cell function

Methionine sulfoxide reductase B (MsrB) is an enzyme that repairs oxidatively damaged proteins by specifically reducing methionine-R-sulfoxide back to methionine. Three MsrBs, localized in different cellular compartments, are expressed in mammals. However, the physiological roles of each MsrB with regard to its location remain poorly understood. Here, we expressed endoplasmic reticulum (ER)-targeted human MsrB3A (hMsrB3A) in Drosophila and examined its effects on various phenotypes. In two independent transgenic lines, both ubiquitous and neuronal expression of hMsrB3A rendered flies resistant to oxidative stress. Interestingly, these flies also showed significantly enhanced cold and heat tolerance. More strikingly, expression of hMsrB3A in the whole body and nervous system extended the lifespan of fruit flies at 29 °C by 43-50% and 12-37%, respectively, suggesting that the targeted expression of MsrB in the ER regulates Drosophila lifespan. A significant increase in lifespan was also observed at 25 °C only when hMsrB3A was expressed in neurons. Additionally, hMsrB3A overexpression significantly delayed the age-related decline in locomotor activity and fecundity. Taken together, our data provide evidence that the ER type of MsrB, MsrB3A, plays an important role in protection mechanisms against oxidative, cold and heat stresses and, moreover, in the regulation of fruit fly aging.     

The metabolic potential of the single cell genomes obtained from the Challenger Deep,Mariana Trench within the candidate superphylum Parcubacteria (OD1)

Candidate phyla (CP) are broad phylogenetic clusters of organisms that lack cultured representatives. Included in this fraction is the candidate Parcubacteria superphylum. Specific characteristics that have been ascribed to the Parcubacteria include reduced genome size, limited metabolic potential and exclusive reliance on fermentation for energy acquisition. The study of new environmental niches, such as the marine versus terrestrial subsurface, often expands the understanding of the genetic potential of taxonomic groups. For this reason, we analyzed 12 Parcubacteria single amplified genomes (SAGs) from sediment samples collected within the Challenger Deep of the Mariana Trench, obtained during the Deepsea Challenge (DSC) Expedition. Many of these SAGs are closely related to environmental sequences obtained from deep‐sea environments based on 16S rRNA gene similarity and BLAST matches to predicted proteins. DSC SAGs encode features not previously identified in Parcubacteria obtained from other habitats. These include adaptation to oxidative stress, polysaccharide modification and genes associated with respiratory nitrate reduction. The DSC SAGs are also distinguished by relative greater abundance of genes for nucleotide and amino acid biosynthesis, repair of alkylated DNA and the synthesis of mechanosensitive ion channels. These results present an expanded view of the Parcubacteria, among members residing in an ultra‐deep hadal environment.     

Isolation of Zoogloea ramigera I-16-M exopolysaccharide biosynthetic genes and evidence for instability within this region.

The genetics of the biosynthesis of an exocellular polysaccharide (EPS) from Zoogloea ramigera I-16-M is being investigated. Tn5 insertion mutants deficient in EPS production were isolated by screening for the absence of fluorescence on plates containing the dye Cellufluor (Polysciences Chemicals). Complementation of these mutations was achieved with a Z. ramigera I-16-M gene library constructed in a broad-host-range cosmid vector and introduced into the I-16-M mutants by conjugation. Four recombinant plasmids able to restore EPS production to all of these mutants were found to contain at least 14 kilobases of common insert DNA. Subcloning of the common region and restriction mapping the locations of Tn5 insertions have identified two complementation groups contained within a chromosomal segment of DNA that is between 4.6 and 6.5 kilobases in size. We have clearly demonstrated genetic instability in this region which leads to spontaneous deletions and possibly rearrangements resulting in the loss of EPS production.     

Sequence organisation in nuclear DNA from Physarum polycephalum. Arrangement of highly-repeated sequences

Recombinant plasmids containing highly repetitive Physarum DNA segments were identified by colony hybridisation using a radioactively-labelled total Physarum DNA probe. A large number of these clones also hybridised to a foldback DNA probe purified from Physarum nuclear DNA. The foldback DNA probe was characterised by reassociation kinetic analysis. About one-half of this component was shown to consist of highly repeated sequences with a kinetic complexity of 1100 bp and an average repetition frequency of 5200. Direct screening of 67 recombinant plasmids for foldback sequences using the electron microscope revealed that about one-half were located in segments of DNA containing highly repetitive sequences; the remainder were present in clones containing low-copy number repeated elements. Analysis of two DNA clones showed that they contained repetitive elements located in over half of all DNA segments containing highly repetitive DNA and that the foci containing these highly repetitive sequences had different sequence arrangements. The results are consistent with the hypothesis that the most highly repeated DNA sequence families in the Physarum genome are few in number and are clustered together in different arrangements in about one-sixth of the genome. Over one-half of the foldback DNA complement in the Physarum genome is derived from these segments of DNA.