GISHGenomic in situ hybridization reveals cryptic genetic differences between maize and its putative wild progenitor Zea mays subsp. parviglumis.

The aim of this paper is to test with genomic in situ hybridization the genomic affinities between maize and its putative progenitor Zea mays subsp. parviglumis. Blocking procedures were applied for the purpose of improving discrimination among chromosome regions. Unlabeled genomic DNA from Z. mays subsp. parviglumis as a blocking agent and labeled genomic DNA from maize were hybridized on maize chromosomes. On the other hand, mitotic metaphases from Z. mays subsp. parviglumis were blocked with unlabeled genomic DNA of maize and hybridized with labeled genomic DNA from Z. mays subsp. parviglumis. Both experiments showed that either maize or Z. mays subsp. parviglumis chromosomes have their own unique sequences. This means an unexpected degree of divergence if Z. mays subsp. parviglumis is the only progenitor of maize, a result that is discussed in relation to our previous genomic in situ hybridization observations and to the different scenarios proposed about the origin of maize.     

Vitellogenin of Blattella germanica (L.) (Dictyoptera, blattellidae): nucleotide sequence of the cDNA and analysis of the protein primary structure

The cloning and sequencing of a cDNA of the vitellogenin gene from the cockroach Blattella germanica is reported. It is 5,749 nucleotides long and encodes an amino acid sequence of 1,862 residues (including a putative signal peptide of 17 residues). The vitellogenin sequence includes a long serine-rich stretch between amino acids 322 and 349, and two other stretches between amino acids 1691 and 1740. The vitellogenin of B. germanica shows a notable similarity (between 32 and 42%) to those described in other insects, and its alignment shows a high number of motifs conserved in all species, especially in the subdomains I-V. Non-parsimony methods (Neighbor Joining) of phylogenetic analysis of the insect vitellogenin sequences gave a tree showing a topology that is, in general, congruent with the currently accepted insect phylogenetic schemes. Arch.     

Root growth dynamics linked to above-ground growth in walnut (Juglans regia)

Background and Aims Examination of plant growth below ground is relatively scant compared with that above ground, and is needed to understand whole-plant responses to the environment. This study examines whether the seasonal timing of fine root growth and the spatial distribution of this growth through the soil profile varies in response to canopy manipulation and soil temperature.Methods Plasticity in the seasonal timing and vertical distribution of root production in response to canopy and soil water manipulation was analysed in field-grown walnut (Juglans regia ‘Chandler’) using minirhizotron techniques.Key Results Root production in walnuts followed a unimodal curve, with one marked flush of root growth starting in mid-May, with a peak in mid-June. Root production declined later in the season, corresponding to increased soil temperature, as well as to the period of major carbohydrate allocation to reproduction. Canopy and soil moisture manipulation did not influence the timing of root production, but did influence the vertical distribution of roots through the soil profile. Water deficit appeared to promote root production in deeper soil layers for mining soil water. Canopy removal appeared to promote shallow root production.Conclusions The findings of this study add to growing evidence that root growth in many ecosystems follows a unimodal curve with one marked flush of root growth in coordination with the initial leaf flush of the season. Root vertical distribution appeared to have greater plasticity than timing of root production in this system, with temperature and/or carbohydrate competition constraining the timing of root growth. Effects on root distribution can have serious impacts on trees, with shallow rooting having negative impacts in years with limited soil water or positive impacts in years with wet springs, and deep rooting having positive impacts on soil water mining from deeper soil layers but negative impacts in years with wet springs.     

Fast induction of vitellogenin gene expression by juvenile hormone III in the cockroach Blattella germanica (L.) (Dictyoptera, Blattellidae).

The present paper describes the effect of juvenile hormone III (JH III) upon vitellogenin (Vg) gene expression in cardioallatectomized females of Blattella germanica. Northern blot analyses of time course studies showed that Vg mRNA can be detected 2 h after the treatment with 1 microgram of JH III. Western blot analyses revealed that Vg protein is detectable 4 h after the same treatment. The study of the influence of the age showed that 48-h-old females seem more sensitive than 24-h-old females, whereas differences were less apparent between 48- and 72-h-old females. Dose-response studies indicated that 0.01 microgram of JH III is ineffective, whereas the doses of 0.1, 1 and 10 micrograms induced the synthesis of Vg in a dose-dependent fashion. Finally, the administration of three successive doses, of 0.01 microgram of JH III each, did not result in detectable Vg production, whereas two doses of 0.01 microgram followed by one of 1 microgram of JH III induced a greater response than that resulting from a sole dose of 1 microgram of JH III, which suggests that sub-effective doses of JH III elicit a priming effect on Vg production.     

Evolution of snake venom disintegrins by positive Darwinian selection

PII-disintegrins, cysteine-rich polypeptides broadly distributed in the venoms of geographically diverse species of vipers and rattlesnakes, antagonize the adhesive functions of beta(1) and beta(3) integrin receptors. PII-disintegrins evolved in Viperidae by neofunctionalization of disintegrin-like domains of duplicated PIII-snake venom hemorrhagic metalloproteinase (SVMP) genes recruited into the venom proteome before the radiation of the advanced snakes. Minimization of the gene (loss of introns and coding regions) and the protein structures (successive loss of disulfide bonds) underpins the postduplication divergence of disintegrins. However, little is known about the underlying genetic mechanisms that have generated the structural and functional diversity among disintegrins. Phylogenetic inference and maximum likelihood-based codon substitution approaches were used to analyze the evolution of the disintegrin family. The topology of the phylogenetic tree does not parallel that of the species tree. This incongruence is consistent with that expected for a multigene family undergoing a birth-and-death process in which the appearance and disappearance of loci are being driven by selection. Cysteine and buried residues appear to be under strong purifying selection due to their role in maintaining the active conformation of disintegrins. Divergence of disintegrins is strongly influenced by positive Darwinian selection causing accelerated rate of substitution in a substantial proportion of surface-exposed disintegrin residues. Global and lineage-specific sites evolving under diversifying selection were identified. Several sites are located within the integrin-binding loop and the C-terminal tail, two regions that form a conformational functional epitope. Arginine-glycine-aspartic acid (RGD) was inferred to represent the ancestral integrin-recognition motif, which emerged from the subgroup of PIII-SVMPs bearing the RDECD sequence. The most parsimonious nucleotide substitution model required for the emergence of all known disintegrin's integrin inhibitory motifs from an ancestral RGD sequence involves a minimum of three mutations. The adaptive advantage of the emergence of motifs targeting beta(1) integrins and the role of positively selected sites located within nonfunctional disintegrin regions appear to be difficult to rationalize in the context of a predator-prey arms race. Perhaps, this represents a consequence of the neofunctionalization potential of the disintegrin domain, a feature that may underlie its recruitment into the venom proteome followed by its successful transformation into a toxin.     

Covalent cell surface functionalization of human fetal osteoblasts for tissue engineering

The chemical functionalization of cell-surface proteins of human primary fetal bone cells with hydrophilic bioorthogonal intermediates was investigated. Toward this goal, chemical pathways were developed for click reaction-mediated coupling of alkyne derivatives with cellular azido-expressing proteins. The incorporation via a tetraethylene glycol linker of a dipeptide and a reporter biotin allowed the proof of concept for the introduction of cell-specific peptide ligands and allowed us to follow the reaction in living cells. Tuning the conditions of the click reaction resulted in chemical functionalization of living human fetal osteoblasts with excellent cell survival.     

Life cycle assessment of construction and renovation of sewer systems using a detailed inventory tool

Purpose

The objective was to provide comprehensive life cycle inventories for the construction and renovation of sewers. A detailed inventory was provided with multiple options of pipe materials, diameters and site-specific characteristics, and was embedded into the Excel^®-based tool SewerLCA. The tool allows for life cycle evaluation of different sewers. It was applied to determine the most important phases, processes, and related parameters involved in the construction and renovation of sewers from an environmental and economical perspective.

Methods

Comprehensive life cycle inventories (LCIs) for sewers construction and renovation were obtained by first identifying all processes involved after interviewing construction experts and reviewing sewer construction budgets from a Catalan company; and second transforming the processes into masses of materials and energy usage using construction databases. In order to run the life cycle impact assessment (LCIA) the materials and energy typologies from the inventories were matched to their corresponding equivalents into available LCI databases. Afterwards the potential impacts were calculated through the use of LCIA characterization factors from ReCiPe. Life cycle assessment (LCA) was run several times to assess the construction of a 1-km-long sewer with varying pipe materials, life spans for each material, diameters, transport distances, site-specific characteristics, and pipe deposition options.

Results and discussion

The environmental impacts generated by construction and renovation of a 1 km Polyvinylchloride (PVC) pipe with a diameter of 40 cm are mainly associated with pipe laying and backfilling of the trench. The evaluation of several pipe materials and diameters shows that the exclusion of renovation would underestimate the impacts by 38 to 82 % depending on the pipe materials and diameters. Including end-of-life phase for plastic pipe materials increases climate change (up to an extra 71 %) and human toxicity (up to an extra 147 %) impacts (among all diameters). The preferred pipe materials from an environmental point of view are precast concrete and High-Density Polyethylene (HDPE). Site-specific characteristics (specially the presence of rocky soil and asphalt placement) and material life span have a high influence on the overall environmental profile, whereas changes in transport distances have only a minor impact (<4 %).

Conclusions

Environmental impacts during the construction and renovation of sewers are subject to differences in material type, site-specific characteristics and material life span. Renovation of sewers has a large influence on all potential environmental impacts and costs and, hence, should not be omitted in LCA studies. The treatment and disposal processes of plastic pipes at the end of their life has to be accounted in LCA studies.

     

Second-order functions are the simplest correlations between flow cytometric light scatter and bacterial diameter

Second-order mathematical relationships between bacterial cell diameter determined by electric particle analyser and flow cytometric forward light scatter in axenic cultures are obtained and discussed. Since it is technically impossible today to obtain both measurements for each individual cell, standard regression techniques cannot be applied. To overcome this limitation, we assume that these two parameters are related by a monotone increasing function that enables their mathematical relationships to be studied. Our conclusion is that forward light scatter data cannot be linearly transformed into bacterial size values by an accurate and universal function. However, second-order relationships seem to be the simplest satisfactory relationships between cell diameter and forward light scatter in eubacteria.