Resistance to pathogens in terpene down-regulated orange fruits inversely correlates with the accumulation of D-limonene in peel oil glands

Volatile organic compounds (VOCs) are secondary metabolites acting as a language for the communication of plants with the environment. In orange fruits, the monoterpene D-limonene accumulates at very high levels in oil glands from the peel. Drastic down-regulation of D-limonene synthase gene expression in the peel of transgenic oranges harboring a D-limonene synthase transgene in antisense (AS) configuration altered the monoterpene profile in oil glands, mainly resulting in reduced accumulation of D-limonene. This led to fruit resistance against Penicillium digitatum (Pd), Xanthomonas citri subsp. citri (Xcc) and other specialized pathogens. Here, we analyze resistance to pathogens in independent AS and empty vector (EV) lines, which have low, medium or high D-limonene concentrations and show that the level of resistance is inversely related to the accumulation of D-limonene in orange peels, thus explaining the need of high D-limonene accumulation in mature oranges in nature for the efficient attraction of specialized microorganism frugivores.     

A New Method to Compare Statistical Tree Growth Curves: The PL-GMANOVA Model and Its Application with Dendrochronological Data

Growth curves are monotonically increasing functions that measure repeatedly the same subjects over time. The classical growth curve model in the statistical literature is the Generalized Multivariate Analysis of Variance (GMANOVA) model. In order to model the tree trunk radius (r) over time (t) of trees on different sites, GMANOVA is combined here with the adapted PL regression model Q = A·T+E, where for and for , A =  initial relative growth to be estimated, , and E is an error term for each tree and time point. Furthermore, Ei[–b·r]  = , , with TPR being the turning point radius in a sigmoid curve, and at is an estimated calibrating time-radius point. Advantages of the approach are that growth rates can be compared among growth curves with different turning point radiuses and different starting points, hidden outliers are easily detectable, the method is statistically robust, and heteroscedasticity of the residuals among time points is allowed. The model was implemented with dendrochronological data of 235 Pinus montezumae trees on ten Mexican volcano sites to calculate comparison intervals for the estimated initial relative growth . One site (at the Popocatépetl volcano) stood out, with being 3.9 times the value of the site with the slowest-growing trees. Calculating variance components for the initial relative growth, 34% of the growth variation was found among sites, 31% among trees, and 35% over time. Without the Popocatépetl site, the numbers changed to 7%, 42%, and 51%. Further explanation of differences in growth would need to focus on factors that vary within sites and over time.     

Data processing for solid substrate cultivation bioreactors

Successful scaling up of Solid Substrate Cultivation (SSC) bioreactors has been hampered by the lack of reliable models that describe such processes satisfactorily. Even though experimental data may be available for model development, data analysis is hindered by system heterogeneity and noisy measurements. This work presents a data processing procedure for periodically agitated SSC fixed bed reactors. The procedure considers several steps. First, all measurements were pre-processed on-line during the cultivation using a low pass fourth order Butterworth digital filter. Then, using this pre-processed data, the average bed temperature, evaporation rate, removed heat, and CO₂ production rate were computed off-line. The variables used to compute the evaporation rate and the removed heat were smoothed off-line with a peak shaving algorithm and a non-delay inducing forward/backward moving average scheme. Variables associated with biomass growth (CO₂ and metabolic heat) are known to evolve slowly. Hence, these were reprocessed with a smoothing procedure in order to diminish the effects of bioreactor heterogeneity. Here, moving average smoothing was applied using a larger window than for other variables, and determined empirically in order to smooth the pre-processed data and extract its real trend. The whole procedure was assessed with data from a 200 kg capacity SSC bioreactor in the cultivation of a filamentous fungus (Gibberella fujikuroi) on wheat bran.     

Radiation techniques used in patients with breast cancer: Results of a survey in Spain

AimTo evaluate the resources and techniques used in the irradiation of patients with breast cancer after lumpectomy or mastectomy and the status of implementation of new techniques and therapeutic schedules in our country.BackgroundThe demand for cancer care has increased among the Spanish population, as long as cancer treatment innovations have proliferated. Radiation therapy in breast cancer has evolved exponentially in recent years with the implementation of three-dimensional conformal radiotherapy, intensity modulated radiotherapy, image guided radiotherapy and hypofractionation.Material and MethodsAn original survey questionnaire was sent to institutions participating in the SEOR-Mama group (GEORM). In total, the standards of practice in 969 patients with breast cancer after surgery were evaluated.ResultsThe response rate was 70% (28/40 centers). In 98.5% of cases 3D conformal treatment was used. All the institutions employed CT-based planning treatment. Boost was performed in 56.4% of patients: electrons in 59.8%, photons in 23.7% and HDR brachytherapy in 8.8%. Fractionation was standard in 93.1% of patients. Supine position was the most frequent. Only 3 centers used prone position. The common organs of risk delimited were: homolateral lung (80.8%) and heart (80.8%). In 84% histograms were used. An 80.8% of the centers used isocentric technique. In 62.5% asymmetric fields were employed. CTV was delimited in 46.2%, PTV in 65% and both in 38.5%. A 65% of the centers checked with portal films. IMRT and hypofractionation were used in 1% and in 5.5% respectively.ConclusionIn most of centers, 3D conformal treatment and CT-based planning treatment were used. IMRT and hypofractionation are currently poorly implemented in Spain.     

The Expanded mtDNA Phylogeny of the Franco-Cantabrian Region Upholds the Pre-Neolithic Genetic Substrate of Basques

The European genetic landscape has been shaped by several human migrations occurred since Paleolithic times. The accumulation of archaeological records and the concordance of different lines of genetic evidence during the last two decades have triggered an interesting debate concerning the role of ancient settlers from the Franco-Cantabrian region in the postglacial resettlement of Europe. Among the Franco-Cantabrian populations, Basques are regarded as one of the oldest and more intriguing human groups of Europe. Recent data on complete mitochondrial DNA genomes focused on macrohaplogroup R0 revealed that Basques harbor some autochthonous lineages, suggesting a genetic continuity since pre-Neolithic times. However, excluding haplogroup H, the most representative lineage of macrohaplogroup R0, the majority of maternal lineages of this area remains virtually unexplored, so that further refinement of the mtDNA phylogeny based on analyses at the highest level of resolution is crucial for a better understanding of the European prehistory. We thus explored the maternal ancestry of 548 autochthonous individuals from various Franco-Cantabrian populations and sequenced 76 mitogenomes of the most representative lineages. Interestingly, we identified three mtDNA haplogroups, U5b1f, J1c5c1 and V22, that proved to be representative of Franco-Cantabria, notably of the Basque population. The seclusion and diversity of these female genetic lineages support a local origin in the Franco-Cantabrian area during the Mesolithic of southwestern Europe, ∼10,000 years before present (YBP), with signals of expansions at ∼3,500 YBP. These findings provide robust evidence of a partial genetic continuity between contemporary autochthonous populations from the Franco-Cantabrian region, specifically the Basques, and Paleolithic/Mesolithic hunter-gatherer groups. Furthermore, our results raise the current proportion (≈15%) of the Franco-Cantabrian maternal gene pool with a putative pre-Neolithic origin to ≈35%, further supporting the notion of a predominant Paleolithic genetic substrate in extant European populations.     

An extra nucleotide in the consensus catalytic core of a viroid hammerhead ribozyme: implications for the design of more efficient ribozymes.

Hammerhead ribozymes catalyze self-cleavage of oligomeric RNAs generated in replication of certain viroid and viroid-like RNAs. Previous studies have defined a catalytic core conserved in most natural hammerheads, but it is still unknown why some present deviations from the consensus. We have addressed this issue in chrysanthemum chlorotic mottle viroid (CChMVd), whose (+) hammerhead has an extra A (A10) between the conserved A9 and the quasi-conserved G10.1. Effects of insertions at this position on hammerhead kinetics have not hitherto been examined. A10 caused a moderate decrease of the trans-cleaving rate constant with respect to the CChMVd (+) hammerhead without this residue, whereas A10-->C and A10-->G substitutions had major detrimental effects, likely because they favor catalytically inactive foldings. By contrast, A10-->U substitution induced a 3-4-fold increase of the rate constant, providing an explanation for the extra U10 present in two natural hammerheads. Because A10 also occupies a singular and indispensable position in the global CChMVd conformation, as revealed by bioassays, these results show that some hammerheads deviate from the consensus due to the involvement of certain residues in critical function(s) other than self-cleavage. Incorporation of the extra U10 into a model hammerhead also caused a similar increase in the rate constant, providing data for a deeper understanding of the hammerhead structural requirements and for designing more efficient ribozymes.     

Differences in prolyl-leucyl-glycinamide metabolism by hypothalamus,pituitary and cerebral cortex of male and female rats

l-Prolyl-l-leucyl-glycinamide is rapidly hydrolyzed by hypothalamic, hypophyseal and cortical homogenates from male or female rats. The peptidase activity is higher in the pituitary followed in decreasing order by the hypothalamus and the cerebral cortex. It is mostly localized in the supernatant fraction of a 100,000 g centrifugation and is inhibited by bacitracin.Tissues from female rats are half as active as those from male rats and show variations during the estrous cycle, with very low PLG metabolism at diestrus 1 in pituitary and hypothalamus. In contrast, the cerebral cortex at proestrus and estrus has significant lower hydrolyzing activity than at diestrus. No change of the peptidase activity is observed in tissues from ovariectomized animals after treatment with estrogen or progesterone.The results obtained suggest the existence of a correlation between peptidasic activity and melanotropin secretion.     

Use of recombinant inbred lines (RILs) to identify, locate and map major genes and quantitative trait loci involved with in vitro regeneration ability in Arabidopsis thaliana

The Landsberg erecta× Columbia recombinant inbred lines (RILs) of Arabidopsis have been used in order to identify and localize chromosome regions involved in the genetic control of the in vitro regeneration ability. Callus morphology (CM) and shoot regeneration (SR) traits have been considered for both leaf and root explants. The MAPMAKER analysis of leaf culture data has revealed at least one chromosome region involved with CM and several with SR, the 29–30 region of chromosome 1 being common for the two traits. Root explants did not segregate for CM but several QTLs have been detected for SR. The chromosome regions involved with leaf culture regeneration seem to be different from those of root cultures, although the regeneration of abnormal shoots in leaf explants share two chromosome regions with the regeneration of normal shoots in root cultures. Received: 19 April 2000 / Accepted: 12 May 2000